-1-
GEOCHEMICAL STUDIES ON HEAVY METALS IN WATERS
AND SEDIMENTS IN MINSTERLEY BROOK, SHROPSHIRE
AND THE RIVER ECCLESBOURNE, DERBYSHIRE
by Brian Reynolds
A Thesis presented for the degree of Doctor of
Philosophy in the University of London
Department of Geology
Imperial College of Science and Technology
London SW7.
September 1981 Abstract
The dispersion patterns downstream, from localised
sources for Cu, Pb, Zn, Cd, Fe, Mn, Ca, and Mg, in river
sediment, "dissolved" water ( < .45 pn) and suspended particulate phases have been described for two river
systems contaminated by historic mining. To determine
the extent of seasonal variation in the levels of metal
in each phase, metal concentrations and water pH were monitored at 10 to 12 sites in each river at two monthly
intervals for a year. The effects of river flow, and
the relationships between metals within the three phases were investigated to identify the factors con-
trolling metal dispersion and transport. The role of
pH, the relationship of metal concentration to sediment
grain size and the ratio of residual to non-residual
metals in the sediments were also studied. Specific
sources for metals within each catchment were identified,
and these included mine adit drainage, collapse and
run-off from mine waste and contaminated bank material
and effluent discharge. -3-
Acknowledqements
I should like to thank my supervisor, Dr. I. Thorntonp for his help and encouragement throughout the project,
Dr. L. Thorne for his guidance and advice, the staff of the Applied Geochemistry Research Group for the provision of laboratory facilities and assistance with the analytical work, and NERC for financial support. I should also like to acknowledge Dr. A. Marples, Dr. S.
Mancey and Miss A. Vernon for their help at various times during the work.
My particular thanks go to Dr. D. Moss of ITE,
Bangor, for much time and energy spent in assistance with the statistics and computing and to ITE for making time and facilities available. I should like to record my sincere thanks to my wife Rachel, for her continued patient support and encouragement and for typing the first draft, and finally my thanks to Mrs. J. Lander for typing the final copy. -4-
CONTENTS
PAGE
Title 1
Abstract 2
Acknowledgements 3
Contents 4
List of Figures 10
List of Tables 13
CHAPTER 1 Introduction 18
1.1 Metalliferous Mining as a Source of _ft Heavy Metals in River Waters
1.2 Toxic Effects of Heavy Metals and Limits 9f. to Water Quality
1.3 Regional Geochemical Data and Water ^ Quality
CHAPTER 2 Literature Review 31
2.1 Amounts of Heavy Metals in Waters 31
2.1.1 Seasonal Variations in Metal Concentrations 31 in Water
2.1.2 Effects of Stream Discharge on Metal Concentrations 34
2.2 Sampling River Water 38
2.2.1 Selection of Sample Sites 39
2.2.2 Sampling Devices and Sample Storage 40
2.3 Filtration of Water Samples 45
2.3.1 Types of Filters 47
2.3.2 Contamination and Adsorption by Filters 50 -5-
CONTENTS
PAGE
2.4 Analysis of Filtrate 51
2.4.1 Chelation - Solvent Extraction 52
2.4.2 Chelating - Ion Exchange Resins 55
2.4.3 Evaporation 57
2.4.4 Co-Precipitation - 58
2.5 Analysis of Suspended Particulates 59
2.6 Forms of Metals in Solution 61
2.6.1 Classification of Metal Species 61
2.6.2 Chemical Modelling 63
2.6.3 Direct Measurement of Metal Species 65
2.6.4 Dissolved Inorganic Species 68
2.6.5 Metal-Organic Species 71
2.7 Levels of Heavy Metals in Stream Sediments 75
2.7.1 Seasonal Variations in Metal Concentrations 7 D in Sediments
2.7.2 Mode of Occurrence of Heavy Metals in Stream Sediments 80
2.8 Chemical Analysis of Stream Sediments 81
2.8.1 Partial Extraction Methods 81
2.8.2 Total Attacks 86
2.8.3 Intermediate Acid Attacks 87
2.9 Particle Size Fractionation of Stream 87 Sediments
2.10 Water-Sediment Interactions 90
2.10.1 Oxidation and Reduction Reactions 90
2.10.2 Interactions with Clays 92
2.10.3 Interactions with Iron and Manganese Oxides 94
2.10.4 Interactions with Organic Matter 97 -6-
CONTENTS
PAGE
2.10.5 Re-mobilisation of Heavy Metals from ^q^ Sediments
2.11 Water-Suspended Sediment Interactions 102
CHAPTER 3 Description of Field Areas 105
3.1 The Minsterley Brook - Rea Brook Catchment 105
3.1.1 General Description 105
3.1.2 Solid Geology of the Minsterley - Rea Brook 109 Catchment
3.1.3 Pleistocene and Recent Deposits in the Minsterley - Rea Brook Catchments
3.1.4 History of Metalliferous and Coal Mining 118 in West Shropshire
3.1.5 Description of Mine Drainage I24
3.1.6 Description of Mine Dumps at Gravels 125
3.2 The River Ecclesbourne Catchment 127
3.2.1 General Description 127
3.2.2 Geology of the Wirksworth Area 131
3.2.3 Geology of the Ecclesbourne Valley 134
3.2.4 Mineralisation and Mining 137
3.2.5 Mine Drainage and Lead Smelting 138
3.3 The Rowberrow Bottom Catchment 139
3.3.1 General Description 139
3.3.2 Geology of the Area Surrounding Rowberrow ^4^ Bottom
3.3.3 Outline History of Mining in the Shipham ^45 Orefield
3.3.4 Sources of Contamination in Rowberrow Bottom 147 -7-
CONTENTS
• PAGE
CHAPTER 4 Geochemical Reconnaissance 149
4. 1 Introduction 149
4. 2 Collection of Stream Sediment Samples 149
4. 3 Analysis of Stream Sediment Samples 153
4. 4 Collection of Stream Water -Samples 153
4. 5 Analysis of Stream Water Samples 156
4. 6 Sample Contamination 158
4. 7 Results and Discussion 160
4. 8 Conclusions 178
CHAPTER 5 A Comparison of Filter Types and Methods for the Determination of Heavy Metals in 180 Suspended Particulate Matter
5. 1 Introduction 180
5. 2 Experimental Methods 182
5. 2. 1 Total Digestion of Membrane Filters 182
5. 2. 2 Leaching of Heavy Metals from Filters 182
5. 3 Determination of Heavy Metals in Suspended 183 Particulates
5. 3. 1 Comparison Between the Existing Method and 183 Wet Acid Digestion
5. 3. 2 Comparison Between the Existing Method and 184 Cold Acid Leaching
5. 3. 3 Total Heavy Metals by Sample Evaporation and 186 Acid Digestion
5. 4 Results and Discussion 186
5. 5 Conclusions 201
CHAPTER 6 Experimental Procedures 203
6.1 Seasonal Stream Sediment and Water Sampling Programme -8-
CONTENTS
PAGE
6.1.1 Sample Collection and Pretreatment 203
6.1.2 Chemical Analysis of Seasonal Samples 205
6.1.3 Assessment of Sampling and Analytical 207 Variation in Seasonal Sediment Data
6.2 Partitioning of Heavy Metals within Stream 207 Sediments
6.2.1 Determination of Residual and Non-residual Heavy Metals in Sediments 208
6.2.2 Size Fractionation of Stream Sediments 208
6.3 Measurement of River Discharge 210
6.4 The Determination of Heavy Metals in Soils, 213 Alluvium and Mine Waste
6.4.1 Sample Collection 213
6.4.2 Chemical Analysis 215
6.5 Determination of Heavy Metals in Shallow 215 Groundwater and Mine Drainage
CHAPTER 7 Analytical Results and Discussion for 2j7 Minsterley Brook and the River Ecclesbourne
7.1 Introduction 217
7.2 Heavy Metals in Alluvium, Mine Waste, Soils 218 and Effluents
7.2.1 Minsterley Brook 218
7.2.2 River Ecclesbourne 235
7.3 Patterns of Metal Dispersion 239
7.3.1 Metal Dispersion in Sediments in Minsterley 240 Brook
7.3.2 Metal Dispersion in Sediments in the River 244 Ecclesbourne
7.3.3 Variations in Minsterley Brook Sediment Data 248
7.3.4 Variations in River Ecclesbourne Sediment Data 258 -9-
CONTENTS
PAGE
7.3.5 Metal Dispersion in Waters in Minsterley 262 Brook
7.3.6 Metal Dispersion in Waters in the River - 269 Ecclesbourne
7.3.7 Variations in Metal Concentrations in Water 276
7.4 Seasonal Variations in Geochemical Data 296
7.4.1 Stream Sediments 296
7.4.2 Filtrable Stream Water Data 304
7.5 Relationships Between Sample Types 310
7.6 Interelement Correlations 321
7.7 Partitioning of Heavy Metals in Stream 33^ Sediments
7.8 Distribution of Metals in Relation to 345 Sediment Grainsize
7.9 Relationships Between Metal Concentrations 3^^ and River Flow
7.10 Analytical Control Data 372
CHAPTER 8 Conclusions and Recommendations for 3QQ Further Research
Bibliography 394
Appendix 1 423
Appendix 2 432
Appendix 3 436
Appendix 4 444
Appendix 5 467 -10-
LIST OF FIGURES
PAGE
FIGURE
1.1 Interim Line Printer Geochemical Map for 30 Cadmium
2.1 Types of Metal Species in Water 62
2.2 Effects of Reaction Temperature and Time on the Extraction of Cu from Sediments 85
2.3 The Relationship Between Surface Area and Trace Metal Adsorption in Sediments 89
3.1 Drainage Plan of Minsterley Brook 106
3.2 Simplified Geology of the Minsterley Brook Catchment 112
3.3 Plan of the Roman Gravels Mine Dump 126
3.4 Drainage Plan of the River Ecclesbourne 128
3.5 Simplified Geology of the River Ecclesbourne Catchment 135
3.6 Drainage Plan of Rowberrow Bottom 142
3.7 Simplified Geology of the Area Surrounding Rowberrow Bottom 143
4.1 Stream Sample Sites, Minsterley Brook 151
4.2 Stream Sample Sites, River Ecclesbourne 152
4.3 Pb in Stream Sediments - Minsterley Brook 162
4.4 Pb in Stream Water - Minsterley Brook 165
4.5 Pb Dispersion in Sediments and Water - Minsterley Brook 166
4.6 Cd Dispersion in Sediments and Water - Rowberrow Bottom 169
4.7 Zn in Stream Sediments - River Ecclesbourne 172
4.8 Zn in Stream Water - River Ecclesbourne 173
4.9 Zn Dispersion in Sediments and Water - River Ecclesbourne 174
6.1 Stream Discharge Measurement by Partial Area Method 211 -11-
LIST OF FIGURES
PAGE
6.2 Soil Sampling Transects across Minsterley Catchment 214
7.1 Description of Dump Borehole at Gravels Mine 221 and Profiles for Pb, Znf Cd and Fe
7.2A Pb in Soils of the Minsterley Catchment - Transect A and B 229
7.2B Pb in Soils of the Minsterley Catchment - Transect C 230
7.3 Pb in Minsterley Brook Bank Soils 232
7.4 Cd in Minsterley Brook Bank Soils 233
7.5 Downstream Distribution of Zn in River Ecclesbourne Bank Soils 235
7.6 Downstream Distribution of Cd in River Ecclesbourne Bank Soils
7.7 Dispersion Plots for Cu, Pb, Zn and Cd in Sediments - Minsterley Brook 241
7.8 Dispersion Plots for Fe, Mn, Ca and Mg in Sediments - Minsterley Brook 243
7.9 Dispersion Plots for Cu, Pb, Zn and Cd in Sediments - River Ecclesbourne
7.10 Dispersion Plots for Fe, Mn, Ca and Mg in Sediments - River Ecclesbourne
7.11 Dispersion Plots for Filtrable Cu, Pb, Zn and Cd - Minsterley Brook 263
7.12 Dispersion Plots for Total Exchangeable Cu, Pb, Zn and Cd - Minsterley Brook 264
7.13 Dispersion Plots for Filtrable and Total Exchangeable Fe and Mn - Minsterley Brook 6
7.14 Dispersion Plots for Filtrable Ca and Mg and pH - Minsterley Brook 267
7.15 Dispersion Plots for Filtrable Cu, Pb, Zn and Cd - River Ecclesbourne 270
7.16 Dispersion Plots for Total Exchangeable Cu, Pb, Zn and Cd - River Ecclesbourne 1 -12-
LIST OF FIGURES
PAGE
7.17 Dispersion Plots for Filtrable and Total 214 Exchangeable Fe and Mn - River Ecclesbourne
7.18 Dispersion Plots for Filtrable Ca and Mg and 275 pH - River Ecclesbourne
7.19A Variations in Metal Concentrations in Stream 298 Sediments with Time - Minsterley Brook
7.19B Variations in Metal Concentrations in Stream 299 Sediments with Time - River Ecclesbourne
7.20A Variations in Filtrable Metal Concentrations 306 with Time - River Ecclesbourne
7.20B Variations in Filtrable Metal Concentrations 307 with Time - Minsterley Brook
7.21 Variations in Mean River Flow with Time 308
7.22 Filtrable Metal Concentrations in Effluent _nq from Wirksworth Water Reclamation Works
7.23 Non-Residual Metal Content of Sediments as a 347 Function of Particle Size - Sites 033 and 10, Minsterley Brook
7.24 Non-Residual Metal Content of Sediments as a Function of Particle Size - Sites 321 and 348 336, River Ecclesbourne
7.25 Non-Residual Cd (Site 33) and Cu (Site 28) Content of Sediments as a Function of Particle 351 Surface Area (Minsterley Brook)
7.26 Non-Residual Cd Content of Sediments as a Function of Particle Surface Area - Sites 03 352 and 31 (Minsterley Brook)
7.27 Non-Residual Cd Content of Sediments as a Function of Particle Diameter (Linear Scale 353 Plot) - Sites 03 and 31, Minsterley Brook
7.28 Regression Plots of Log^Q Discharge with Log^g ^^ Load for Mg and Cu - River Ecclesbourne
7.29 Regression Plots of Log^g Concentration with Log^Q Discharge for Pb, Zn, Cd and Ca - 371 Minsterley Brook -13-
LIST OF TABLES
PAGE
TABLE
1.1 Toxic Levels of Dissolved Heavy Metals iri Fresh Water 22
1.2 Factors Influencing the Toxicity of Heavy 24 Metals in Solution to Aquatic Organisms
1.3 EEC Commission Directives for Levels of Heavy Metals in Waters Used for Drinking Water 25 Abstraction
1.4 Highest Desirable Limits for Trace Heavy Metals in Drinking Water (WHO 1971) 26
1.5 Recommended Limits for the Concentration of 27 Metals in River Water Used for Irrigation
2.1 Reported Average Concentrations and Ranges in 32 Concentration for Metals in River Water
2.2 The Occurrence of Metals in Stream Sediments 76 of England and Wales
3.1 Effluent Analyses - Minsterley Brook 110
3.2 Names and Locations of Drainage Adit Portals and Some Mines in the Minsterley Brook 119 Catchment
3.3 Effluent Analyses - River Ecclesbourne 132
3.4 Names and Locations of Soughs Draining into 140 the Ecclesbourne Catchment
3.5 Levels of Heavy Metals in Soils from Rowberrow ^g Bottom
4.1 Resonance Lines, Sensitivities and Detection Limits for the Perkin-Elmer 403 Atomic 154 Absorption Spectrophotometer
4.2 Detection Limits for Stream Sediment Analyses, Nitric Acid Attack
4.3 Detection Limits for Water Analyses Following ^g Solvent Extraction
4.4 Mean Concentrations of Metals in Control ^g Analyses -14-
LIST OF TABLES
PAGE
TABLE
4.5 Mean Percentage Recoveries from Spiked ^g Samples of DIW
4.6 Pb*, Zn and Cd Concentrations in Stream Sediments from Minsterley Brook
4.7 Filtrable and Total Pb, Zn and Cd Concentra- tions in Minsterley Brook Water
4.8 Pb, Zn and Cd Concentrations in Stream 168 Sediments from Rowberrow Bottom
4.9 Filtrable and Total Pb, Zn and Cd Concentra- 168 tions in Water from Rowberrow Bottom
4.10 Pb, Zn and Cd Concentrations' in Stream Sediments from the River Ecclesbourne
4.11 Filtrable and Total Pb, Zn and Cd Concentra- ^^ tions in Water from the River Ecclesbourne
4.12 Filtrable Ca and Mg Concentrations and pH ^77 of Water from Minsterley Brook and the River Ecclesbourne
5.1 Mean Metal Contents of Sartorius Filters 188
5.2 Trace Metal Contents of Whatman GF/C Filters 188
5.3 Mean Metal Contents of Samples of DIW 188
5. A Filtrable and Suspended Particulate Concentra- tions of Heavy Metals in Rowberrow Bottom 190 Samples
5.5 Filtrable Metal Concentrations in River -^3 Ecclesbourne Samples
5.6 Results of MtM-test Comparing Filtrable Metal Data
5.7 Particulate Metal Concentrations in River ^94 Ecclesbourne Samples
5.8 Total Exchangeable Metal Concentrations in River Ecclesbourne Samples
5.9 Results of "t"-tests Comparing Data in Table 5.7 -15-
LIST OF TABLES
PAGE
TABLE
5.10 Total Exchangeable Metal Concentrations in Duplicate Samples
7.1 Mean Concentrations of Metals in Mine Waste from Gravels Dump 220
7.2 Chemical Data for Mine Dump Borehole 220
7.3 Heavy Metal Content of Ore Samples from 220 Gravels Mine
7.4 Chemical Data for Mine Dump Drainage and Groundwater
7.5 Concentrations of Metals in Drainage Adit Effluents 222
7.6 Concentrations of Metals in Shale Samples ^oo from Minsterley Brook
7.7 Heavy Metals in Effluent from Wirksworth W.R.W. 238
7.8 Statistics for Replicate Sediment Analyses 250
7.9 Results of 1-Way ANOVA Performed on Replicate ? Sediment Data
7.10 Results of 2-Way ANOVA Performed on Minsterley _ Sediment Data b
7.11 Results of 2-Way ANOVA Performed on Ecclesbourne Sediment Data 261
7.12 Analyses of Replicated Water Samples from Minsterley Brook 278
7.13 Analyses of Replicated Water Samples from the River Ecclesbourne 282
7.14 Concentrations of Suspended Solids in Streamwater Samples 287
7.15 Chemical Composition of Suspended Solids from ? _ Minsterley Brook - Sampling Occasion 08/78
7.16 Chemical Composition of Suspended Solids from the River Ecclesbourne - Sampling Occasion 291 08/78 -16-
LIST OF TABLES
PAGE
TABLE
7.17 Results of 1-Way ANOVA Performed on Replicate Samples from Minsterley Brook and the River 293 Ecclesbourne
7.18 Results of 2-Way ANOVA Performed on Minsterley 2 . Water Data
7.19 Results of 2-Way ANOVA Performed on River 295 Ecclesbourne Water Data
7.20 Correlations of Concentration of Metals in ^00 Stream Sediments with River Flow - Minsterley Brook
7.21 Correlations of Concentration of Metals in Stream Sediments with River Flow - River 300 Ecclesbourne
7.22 Correlations between Sample Types - 312 Minsterley Brook
7.23 Correlations between Sample Types - River ^14 Ecclesbourne
7.24 Mean Percentage Filtrable Heavy Metals - 3^ Minsterley Brook
7.25 Mean Percentage Filtrable Heavy Metals - 320 River Ecclesbourne
7.26 Interelement Correlations for Minsterley 323 Seasonal Data
7.27 Interelement Correlations for River 325 Ecclesbourne Seasonal Data
7.28 Interelement Correlations for Nitric-Perchloric^27 Attack Data
7.29 Proportions of Non-Residual Heavy Metals in 333 Minsterley Sediments
7.30 Proportions of Non-Residual Heavy Metals in 334 River Ecclesbourne Sediments
7.31 Analyses of Heavy Minerals Separated from 335 Minsterley Sediments
7.32 Ratios of Mn/metal and" Fe/metal for Oxide Coatings - Minsterley Brook 340 -17-
LIST OF TABLES
PAGE
TABLE
7.33 Ratios of Mn/metal and Fe/metal for Oxide 344 Coatings --River Ecclesbourne
7.34 Weights of Sediment Size Fractions 346
7.35 Values of River Discharge for Rea Brook (Site 134) and the River Ecclesbourne 358 (Site 327)
7.36 Coefficients for Load and Concentration 359 Regression Equations for Minsterley Brook
7.37 Coefficients for Load and Concentration 360 Regression Equations for the River Ecclesbourne
7.38 Estimated Losses of Dissolved Metals from the g^g Rea Brook Catchment, Nov 1977 - Oct 1978
7.38A Estimated Losses of Metals Associated With ^^4 Suspended Solids from Rea Brook
7.39 Estimated Losses of Dissolved Metals from the River Ecclesbourne Catchment, Oct 1977 - 366 Sept 1978
7.39A Estimated Losses of Metals Associated With Suspended Solids from the River Ecclesbourne
7.40 River Flow at Sample Sites on Minsterley Brook 368
7.41 Regression Coefficients for Concentration - -^-jq Flow Equations for Minsterley Brook
7.42 Results of Analyses of Replicate Bulk Water ^74 Samples
7.43 Recoveries from "Spiked" and Control Samples 07c of DIW
7.44 Analyses of Standardised Sediment Samples 376 -18-
CHAPTER I
INTRODUCTION
Metalliferous Mining as a Source of Heavy Metals
in River Waters
The presence of anomalous concentrations of trace metals in stream sediments, waters and soils in the vicinity of ore deposits is well known and forms the basis of several methods used in explor- ation geochemistry. The exploitation of ore dep- osits leads to the exposure of large quantities o^nA So of waste rockj^to accelerated weathering conditions
(Leckie and James 1974). Although material in waste dumps is usually too low grade to be of interest economically, it is still highly concen- trated in trace metals compared with background levels, often containing >1% and occasionally
>4% w/w residual metals (Johnson and Bradshaw
1977). Metals may be released to the environment through mining, ore processing and smelting via mine drainage, process water, surface run-off from spoil tips and by volatilisation. Once introduced into standing water, heavy metals tend to remain there, though diurnal and annual cycling can cause alteration of metal form and location.
After initial mixing, heavy metals entering stream water are diluted only by inputs from uncontaminated -19- streams or by incorporation into stream sediments. They tend to concentrate in estuaries and sheltered coastal waters (Thornton et al 1975). Heavy metals may enter groundwater by percolation or when mining has penetrated the watertable. As natural filtra- tion rates are slow, these metals may be very per- sistent in groundwater (Down and Stocks 1977).
Metalliferous mining on the scale of the "New Lead Belt" in Missouri, U.S.A., or the gold fields of the Witwatersrand in South Africa, does not occur in England and Wales at present. However, the remains of historic mining can have a signif- icant effect on water quality. In mid-Wales for example, in the catchment of the River Ystwyth, lead and zinc were mined from Roman times to the end of the 19th. century. The contamination of this river and the adjacent River Rheidol by lead and zinc has been well documented (e.g. Carpenter 1924, Jones 1940, 1958, Davies and Lewin 1974, Grimshaw et al 1976). These rivers are also thought to provide the dominant source for marine metal pollutants in Cardigan Bay (Abdullah et al 1972). Seasonal variations in the heavy metal content of a number of marine organisms in Cardigan Bay have been related to seasonal variations in the supply of the metals by the rivers to the bay. (Grimshaw et al 1976). -20-
Past lead-zinc mining in the Llanrwst area
to the west of the Conway river in North Wales
caused considerable contamination of local streams.
Sediments of streams draining the disused mines
to the west of Llanrwst contained up to 1% of lead
and*zinc accompanied by up to 3,000 yxq/l Zn in the
contaminated water compared with 25 ug/l in uncon-
taminated tributaries. Water in the Conway estuary
was found to have 100 )iq/l Zn compared with 9 )xq/l
in local sea water (Elderfield et al 1971). These
results have been related to problems at an oyster
hatchery in the Conway valley (Elderfield et al
1971). Similar studies can also be cited for a
number of rivers in Cornwall (Thornton et al 1975,
Aston and Thornton 1977), the River Tawe in South
Wales (Vivian et al 1977), and rivers in Derbyshire.
1.2 Toxic Effects of Heavy Metals and Limits to Water
Quality
An element is said to be toxic if it injures
the growth or metabolism of an organism when sup-
plied above a certain concentration. Heavy metals
can be classified into thosej
i) Essential for growth i.e. Cr, Co, Cu, Fe,
Mn, Zn.
ii) Possibly essential i.e. Ni. -21- iii) Non-essential for growth i.e. Pb, Cd - toxic
even at low concentrations (Morris 1978).
Essential heavy metals as micro-nutrients
in minute concentrations may be highly toxic
when present in excess even at low absolute
* concentrations.
The adverse effects of heavy metals on human health have long been recognised. However, in connection with mining, immediate effects of en- vironmental exposure on human health are rare
(although the effects of long term exposure to low levels of toxic heavy metals are as yet largely unknown). The greatest impact is normally in the aquatic ecosystem (Down and Stocks 1977). An exception to this was the outbreak of the cadmium- induced "itai-itai" disease in the Zinzu River area of Japan between 1940 and 1965 (Nomiyama 1975).
The source of the cadmium was thought to be the
Mitsui Mine (Pb/Zn) some 50 km upstream of the affected area.
The toxicity of a number of heavy metals to freshwater aquatic organisms is shown in Table 1.1.
The toxic effects of copper on many species of algae is well known, and the effects of zinc, copper, cadmium and chromium iv have been discussed in detail (FWPC 1968). Additionally, many organisms and plants can markedly concentrate metals from -22-
Table 1.4
Toxic Levels of Dissolved Heavy Metals in Fresh Water
Metal * Lethal Concentration Organism (mq/l)
Cu 0.01 - 0.02 • Fish*
Cu (as CuS04) 0.14 Trout Cu i« 0.75 Perch
Cu •• 2.1 Black Bass
Cu •• 0.1 Blue-green Algae Zn 0.15 - 0.7 •Fish* Be 0.2 Fathead Minnows
Cr (as NaCr04) 0.1 Water Fleas
Cr •• 20.0 • Fish* Pb (0.1) -0.5 - 1.0 Bacteria
Pb 0.01 - 10.0 Water Fleas Pb 3.3 - 10.0 Tadpoles
Pb (as PbCl2) 3.0 - 60.0 Green Algae Pb 2.4 (soft water) Fathead Minnows Pb >75.0 ' (hard water) Fathead Minnows
(From Down and Stocks 1977) -23-
water (Burton and Peterson 1979, Ray and White
1976) , and this can lead to the possibility of
transfer of harmful concentrations through the food
chain. The terminal consumer (man) may thus ingest
a damaging quantity of metal (Down and Stocks 1977)•
The 'toxicity of heavy metals in solution to aquatic
organisms is determined by a number of factors,
summarised in Table 1.2. For example, toxicity
depends on the chemical species as well as concen-
tration (Bryan 1971).
The growing need to use river water as a source
of drinking water also throws emphasis on the per-
missible concentrations of heavy metals in waters.
The EEC and the WHO have recommended concentration
limits for surface waters intended for drinking
water abstraction. These levels are given in Tables
1.3 and 1.4. Stringent limits have also been sug-
gested for the concentrations of several metals in
river waters intended for irrigation; these are
shown in Table 1.5.
1.3 Regional Geochemical Data and Water Quality
The application of regional stream sediment
geochemical reconnaissance data to the prediction
of the trace element composition of river waters
for drinking water abstraction was suggested by
Webb (1973). Since that time a number of inves-
tigations concerning this application have been -24-
Table 1.2
Factors Influencing the Toxicity of Heavy Metals in
Solution to Aquatic Organisms
i) Form of metal in water
ion complex ion inorganic soluble chelate molecule
colloidal organic particulate precipitated adsorbed
ii) Presence of other metals or poisons, iii) Factors influencing physiology of organisms and
possible form of metal in water: temperature, pH,
dissolved oxygen, light, salinity,
iv) Condition of organism, e.gj stage (egg, larva etc.),
changes in life cycle (moulting, reproduction), age,
sex, nutrition, activity, adaption to metals.
(From Thorne 1978) A1(G) A1(I) A2(G) A2(I) A3(G) A3(I)
pH 6.5 8.5 5.5 9.0 5.5 4.0
Conductivity 1000 1000 1000
Fe 0.1 0.3 1
Mn 0.5 0.1 1
Cu 0.02 0.05 0.05 1
Zn 0.05 3 1 5 1 5 V 0.05 0.05 0.05
As 0.01 0.05 0.05 0.10 Cd 0.001 0.005 0.001 0.005 0.001 0.005 Cr 0.05 0.05 0.05 Pb 0.05 0.05 0.05
Sc 0.01 0.01 0.01
Hg 0.0005 0.001 0.005 0.001 0.0005 0.001
G = Guide value I = Mandatory value Al Rapid filtration A2 Physical filtration A3 Intensive refining
Water which contains metals greater than the directives concentrations derived solely from natural geoehemical inputs are exempted. Levels in mgl * at abstraction points. -26-
Table 1.4
Highest Desirable Limits for Trace Heavy Metals in * Drinking Water (WHO 1971)
Element HDL Value (pg/l)
Fe 100 Mn 500 Cu 50 Pb 50 Zn 5000
Cd 10 As 50 -27-
Table 1.2
Recommended Limits for the Concentrations of
Metals in River Water used for Irrigation
Concentration Metal Limit (uq/l)
Aluminium 1,000
Beryllium 500
Cadmium 5
Chromium 5,000
Cobalt 200
Copper 200
Molybdenum 5
Nickel 500
Zinc 500
From t FWPCA (1968) -28- conducted, (Aston and Thornton 1975 and 1977, Aston et al 1974). Regional geochemical data based on the sampling and multi-element analysis of active tributary drainage sediments is thus intended to provide useful ancillary information on the likely rancfe of concentrations of potentially toxic ele- ments in river waters. The publication of the
Wolfson Geochemical Atlas of England and Wales
(Webb et al 1978) has extended the possibilities for the use of stream sediment geochemical data in this context to a wide geographical area. This atlas comprises lasergraphically printed colour maps at 1:2000,000 scale depicting the regional distribution of twenty one elements in active stream sediments collected at 50,000 sites through- out England and Wales. This gives a mean sampling density of one sample per square mile. In addition to single element maps, combined element maps are included for Cu-Co-Zn, Mo-Cu, Pb-Cu-Zn and Cd-Zn-Pb.
The latter two combinations are particularly use- ful for delineating former base metal mining areas.
An example of an interim line printer map for Cd, produced in 1974, is shown in Figure 1.1.
The trace element composition of stream sed- iments has been shown to provide a stable indica- tion of the composition of associated river water
in a number of geochemical environments. A detailed study of seasonal variations in trace element com- -29- positions of sediments and waters was conducted by Aston and Thornton in 1977. This work was done in a "soft water" area in south west England. The work described in this thesis extended the inves- tigations into hard water areas. In addition some* of the processes controlling the distribution of heavy metals in waters and sediments have been examined. The preliminary choice of field areas for study was made using the Wolfson Geochemical
Atlas of England and Wales, see Figure 1.1. The areas delineated on the small scale maps were ex- amined more closely using point source data ret- rieved from computer file storage and plotted at
1:50,000 scale. Three catchments were selected from point source maps, namely Minsterley Brook,
Shropshire (Area I, Figure 1.1), the River
Ecclesbourne, Derbyshire (Area 2, Figure 1.1) and
Rowberrow Warren, Mendip Hills in Somerset (Area 3,
Figure 1.1). All three catchments are situated in areas of historic base metal mining and are contaminated to some extent by Cu, Pb, Zn, and Cd.
A pilot reconnaissance study was conducted to investigate the suitability of the catchments for the intended work. -30-
Fi^ure 1.1. Interim Line Printer Geochemical Map for Cadmium
Cadmium (ppm)
< 1 111! 1-2 MS -31-
CHAPTER 2
LITERATURE REVIEW
2.1 Amounts of Heavy Metals in Water
Table 2.1 gives reported average concentrations
and ranges in concentration for a number of heavy
metals. The table is adapted from Wilson (1976),
who has recently reviewed several hundred papers
containing data on concentrations of metals in river
water.
In considering the chemistry of trace elements
in river waters it is clear that large variations
in concentrations can occur. A single determination
of a given element concentration in a river cannot
be considered typical of the whole system. Values
based on a single water sample can vary by 200% or
more from the mean concentration determined for the
river (Angino et al 1969). Two important factors
that can contribute to these variations are con-
sidered below.
2.1.1 Seasonal Variations in Metal Concentrations in Water
A number of authors mention seasonal effects
on the concentrations of trace metals in water,
including Angino et al (l969), Kharkar et al (l968),
Depetris (1976), Silker (l964^ Gibbs (l97 2), Webb and
Millman (1950). However, as Wilson (1976) points Table 2.1 Reported Average Concentrations and Ranges in Concentration for Metals in River Water
Riley & Chester Bowen Durum & Haffty Turekian Wilson (1971) (1966) (1963) (1971). (1976)
Cu 5 10 5.3 7 7 0.6-400 0.8-105 0.5-50
Pb 3 5 4 3 5 0.6-120 0-55 1-100
Zn 10 10 0 20 25 0.2-1000 0-215 2-200
Cd - 0.08 - - 1 0.1-10
Fe 670 670 300 - 35 10-1400 31-1670 3-300
Mn 5 12 20 7 5 0.02-130 0-185 1-100
Co 0.2 0.9 0 0.2 0.5 0-6 0-5.8 0.1-10 i Ni 0.3 10 10 0.3 10 0.2-20 0-71 0.5-50
Modified from Wilson (1976) Units t jmg/l -33- out, although many reasons are apparent for such effects many authors have not distinguished true seasonal effects, i.e. those due to biological and chemical activity, from those associated with discharge. Elder et al (1976) have shown that seasohal variations in iron concentrations in one particular stream reflect both biological activity and the influences of run-off and discharge. The availability of iron in the stream was related to algal activity and its transport to snow melt run-off.
Aston and Thornton (1977) in a study on some
Cornish rivers showed that the greatest seasonal range in concentrations of heavy metals occurred in the mineralised/mined tributaries. This was explained as a consequence of the physical and chemical mobilisation of abundant metal sources in the soils and groundwater of the mineralised catchment during the seasons.
There have been few studies providing unequivocal evidence for short term fluctuations in metal content. Downing and Edwards (1969) quote results for Cu in a river which display regular diurnal fluctuations in concentration, with maxima and minima of approximately 250 jig/l and 60 yg/l Cu respectively. They give no reason for the pattern, but it is possible that an effluent -34-
discharge could have been involved. Lee and
Hoadley (1967) have suggested that variations in
metal concentration of this sort may occur as a
result of the diurnal cycle of biotic activity.
Recently Whiting (1978) studied the variations
in metal levels in the water of the River Hayle,
Cornwall, occurring between sites, between days
and between times within a day. The data were
analysed statically using 2-way analysis of
variance. A pronounced and consistent variation
in metal concentration was demonstrated between
sample sites. However, no significant variation
occurred between days or between times and no
consistent patterns were identified. Exceptions
were Zn and Ni, where the highest concentrations
were consistently found early in the day.
2.1.2 Effects of Stream Discharge on Metal Concentrations
Many authors have mentioned the effects of
flow related to seasonal variability in trace
metal concentrations in water. In considering
the relationship between concentration and discharge,
the general pattern seems to be one of no consistent
effects (Andelman 1973, Durum and Haffty 1961 and
1963). One interpretation of the various inter-
actions that affect the discharge/concentration
relationship for both the filtrable and particulate
phases has been presented'by Wilson (1976). Two -35- important processes are suggestedi i) a decrease in the filtrable concentration by dilution, and ii) an increase in the suspended solid load by re-entrainment of bed sediments with increased discharge (Williams et al 1973) . Though -these processes may operate in general terms for most metals, their relative and absolute magnitudes will depend on a number of variables e.g. ratio of dissolved to particulate metals, metal content of sediment, adsorption of dissolved metals by sediments etc. Also the applicability of this hypothetical scheme can often be at variance with results determined in the field. The scheme does not account for the trace element load associated with water of varying quality entering the main system from tributaries. Silker (1964) found that the annual spring increase in the concentrat- ions of As, Mn, Cu, and La in the Columbia river could be related directly to the increased contri- butions of these elements by one tributary.
Angino et al (1974), in a detailed study of some Kansas rivers, found that correlations between trace element concentrations and discharge were infrequently seen. This applied equally to the filtrable and non-filtrable phases. This feature relating to particulates has also been reported by
Turekian and Scott (1967).
It seems unlikely that the real effects of -36- discharge on metal concentration will be established without detailed investigations at many different discharges, of both filtrable and non-filtrable metal concentrations. Some studies of this sort exist e.g. Edwards 1973b, Glover and Johnson 1974,
Walling and Foster 1975, but these have been mainly concerned with major cations, i.e. Ca^+, Mg^ + , K+, and Na+, and anions. Walling and Foster (1975) have found that even in a small stream, the behaviour of dissolved elements in response to increasing discharge is very variable. Certain solute species such as K and NO^ may increase rather than decrease in concentration with increased discharge.
The behaviour of elements displaying dilution, such as Ca and Mg, is often complicated by an initial flushing effect. This is a process whereby a large proportion of the weathered salts, accumulated in the soil profile during warm dry weather prior to a storm, is rapidly removed to the stream during the first, but not necessarily the largest, pulse of run-off. Flushing occurs a short period before discharge has significantly increased, and can lead to very high metal levels in the stream.
Clearly, antecedent weather conditions are important in this process. Grimshaw et al (1976) found that the highest concentrations of Zn throughout the period of study on the River Ystwyth were associated -37- with these flushing events. After flushing had occurred the dissolved Zn concentration decreased with increasing discharge due to dilution.
K and NO^ can also exhibit a varying response
to different events, sometimes showing an increase
in concentration with discharge, sometimes a decrease. The chemical response of a stream can also lag behind, sometimes by several hours, the stream flow response. For example, a lag of 14.5 hours between chemical and stream flow responses has been demonstrated for a small stream in Devon
(Glover and Johnson 1974).
The importance of conditions prior to the onset of a storm have also been stressed. Walling and Foster (1975) have stated that all the processes interposed between storm rainfall and channel input occurring over the entire catchment must be con- sidered if a full understanding of the chemical
response of a stream to increased discharge is to be attained. This would include factors such as soil moisture status of the catchment prior to
rainfall, the location of elements within the soil profile and the nature of the run-off component such as land drains, surface flow and ditches.
Another important consideration, particularly with summer convective storms, is the possibility of unevenly distributed rainfall over a catchment. -38- This will directly affect the source areas for
run-off. This is especially significant in areas
where sources of heavy metals are localised, as in
mine dumps and mineral veins, (Grimshaw et al 1976)
The run-off from these areas will carry a higher —
metal load than that from non-mineralised regions.
Although the relationship between metal
concentration and discharge is complex, the solute
load of individual elements is discharge dependent,
(Edwards 1973a). Similarly, the element load
associated with suspended matter is also dependent
on discharge; doubly so, as the total suspended
solid concentration is also dependent on discharge
(Angino et al 1974). Thus an appreciation of the
flow pattern of a river is essential in determining
trace element budgets and in the prediction of peak
concentrations of pollutants.
» 2.2 Sampling River Water
The first step, and by some considered the
most important in the analysis of trace metals in
waters,is sample collection (Hamilton 1976). The
sample must obviously represent the quality of the
water of interest, and though the error for a
particular analytical method may be low, consi-
derable errors can be introduced during sampling
and sample storage (Batley and Gardner 1977).
These errors can be very-significant when working -39- at the pg/l level (Tolg 1972, Mitchell 1973).
2.2.1 Selection of Sample Sites
The concentration of a metal at a given point
on a river may vary with depth and distance from
the'bank. This inhomogeneity is particularly
significant where particulate forms of the metal
are present, and/or discharges or tributaries enter
the main stream a short distance upstream from the
sample point. It is important to sample at points
where the metal concentrations will be uniformly
distributed throughout the cross-section of the
river, (Cheeseman and Wilson 1973). If this is
not possible then any time-based sampling should
be carried out from the same location each time.
When taking the sample, it is important to avoid
any surface material, such as floating organic
debris or oil, that might enter the sampling
container and contaminate the sample.
The concentration of metals has been shown
to vary even along a river which is unpolluted
(Angino et al 1974, Turekian et al 1967, Kharkar
et al 1968). Thus it has been stressed that a single
sample from a river cannot be considered represent-
ative of that river (Wilson 1976, Angino et al 1974).
Large variations in metal concentration can occur
for a number of reasons on a temporal basis and this -40-
must be considered when planning a sampling programme
(Wilson 1976, Angino et al 1974).
2.2.2 Sampling Devices and Sample Storage
Natural waters are-mixtures containing biolo-
gical and chemical species in dynamic equilibrium.
When a water sample is brought into contact with
oxygen and container walls or subjected to physical
changes of temperature and pressure, this equilib-
rium may be disturbed (Batley and Gardner 1977) .
In unfiltered samples, contact of the dissolved
fraction with particulate matter can cause changes
in the distribution of chemical species within the
water. Equilibrium times for sorption and desorption
processes are rapid (Gardiner 1974b), and with any
change in solution equilibrium adsorption sites on
particulate matter can form a pathway for the
removal of metals from solution (Murray and Meinke
1974). Desorption of adsorbed metal is also possible
under certain conditions.
High bacterial concentrations can lead to
depletion in soluble species (Lee and Hoadley 1967).
The nature of algal growth in stored untreated water
samples is unpredictable (Moebus 1972). Growth of
organisms involving photosynthesis and respiration
will produce a change in the carbon dioxide content
of the water. Changes in water pH may then occur, -41- which can result in precipitation of metal salts, or changes in complexation and adsorptive behaviour of heavy metals. Thus filtration should be performed as soon "as possible after collection of the sample.
If this-is not done, chilling to 4°C will retard bacterial growth in the unfiltered samples (Carpenter J.H, et al 1975).
Losses of heavy metals by adsorption to container walls can also occur (American Public
Health Association 1971). This process has been studied by a number of workers, including Smith
1973a and 1973b, Streumpler 1973, and Robertson
1968b; work undertaken by the latter author probably represents the most extensive study. Acidification of the sample to pH <1.5 with concentrated nitric or hydrochloric acid (Smith 1973a and 197313 will eliminate or at least very much reduce losses by adsorption presumably by the preferential adsorption of H* ions from solution. Even so, Streumpler found that up to 60% of the lead was lost from solution by adsorption to container walls in samples stored in polyethylene or polypropylene bottles at pH <2.
Borosilicate glass was effective at maintaining lead in solution at pH 2 however. Elderfield (1971) has shown that water samples acidified to pH 2 are stable with respect to soluble trace metal content for up to 20 days, and Ediger (1973) has claimed
that acidified samples are stable for 30 days. -42-
As can be seen acidification of the water sampl is desirable in order to preserve it. This is not feasible however until after filtration in cases where analysis of the particulate matter is required
Where metal speciation studies are to be conducted, acidification is not possible. Florence (1977) has shown that storage, after filtration, at 4°C will minimise losses by adsorption and changes in metal speciation. Freezing is not recommended as changes in metal speciation can occur, although the total metal concentration may remain the same (Florence
1977) .
The choice of materials for sample containers can also affect the adsorption behaviour of trace metals. In general adsorption losses appear to be lower on polyethylene and Teflon than on Pyrex
(borosilicate) glass (Batley and Gardner 1977).
The application of hydrophobic silicone coatings to Pyrex glass has been shown to reduce the adsorp- tion of a number of heavy metals (Eicholz et al
1965) . It should also be noted that whilst acid leaching is essential for the removal of surface contamination from sample bottles, this process can also re-activate adsorption sites capable of removing trace elements from solution. For this reason, it is important to rinse containers well with deionised water and sample water before collection of the required sample, (Batley and -43-
Gardner 1977). Aged sample containers with fewer active surface sites are preferable to new ones,
(Smith 1973a). Ntlrmberg et al (1976) recommend that sample containers be conditioned before use.
This is achieved by allowing the containers to stand for several hours filled with a solution containing lg/1 CaSO^ and lg/l MgSO^. Adsorption losses at natural pH for a number of trace elements were virtually eliminated by this process.
Containers are also potential sources of contamination, even when apparently thoroughly cleaned. Ediger (1973) has stressed the need for contaminant free containers and recommends Teflon, with polyethylene as an alternative. Robertson
(1968a) has made an extensive study into contamin- ation in trace metal analysis and has shown that polyethylene contains extremely small concentrations of metals. As mentioned, Pyrex glass can also be used for containers although some contamination by this material has been reported (Robertson 1968a).
In general, however, surface metal impurities can be removed by acid leaching. Karin et al (197 5) recommend a three day leach with 8N nitric acid for optimum removal of trace metals from polyethy- lene surfaces. Watling (1974) found that leaching with 10% v/v nitric acid for a minimum of twenty four hours was sufficient to clean aged bottles though more intensive treatment was required for -44- new ones. Streumpler (1973) found however, that polypropylene containers remained severely contam-
inated with Zn and Cd even after thorough acid washing.
For the collection of samples in the field, polyethylene is to be recommended in preference
to glass as it is less liable to breakage. High
density polyethylene bottles should be used for
sampling as water vapour can pass through the low
density material causing changes in metal concen-
tration (Robertson 1968a, Cox 1953). Contamination
can also occur by leaching of material from caps
and stoppers, and rubber, metal, or cardboard
inserts should be removed.
Ideally it should be possible to circumvent
the many problems associated with sampling and
storage of water by in-situ analytical methods.
Measurement probes for Cu, Pb, Cd and other metals
do exist (Orion Research Inc. 1975, Alexander 1976).
Their detection limits are, however, of the order —7 —8
of 10 to 10 M under optimum conditions, which
precludes their use in all except highly polluted
waters. There are also possibilities for in-situ
measurements using Anodic Stripping Voltammetry,
(Zirino and Lieberman 1975). Other analytical
techniques require some form of sample pre-
concentration; preventing their use for in-situ
measurements. In-situ sampling and pre-concentration -45-
have been reported for river water (Shuman and
Dempsey 1977), and sea-water (Davey and Soper 1975).
These use continuous flow filtration and ion exchange
resins. Although this eliminates the uncertainties
related to the unpreserved storage of samples,
heavy metals bound to organic colloids and fine
particulates will not be removed from the sample
using resins such as Chelex-100 at the natural pH
of the water (Florence and Batley 1976).
2.3 Filtration of Water Samples
Metals in water can occur in soluble or
particulate forms, and it is often desirable to
determine the concentrations of each form. Although
this can be achieved by the choice of a suitable
analytical procedure such as ion selective electrodes
which only respond to free hydrated metal ions, it
is generally necessary to achieve some form of
physical separation of the phases and to analyse
them individually.
This separation can be achieved by centrifu-
gation, commonly by use of continuous flow ultra-
centrifugation (Benes and Stemnes 1975, Perhac
and Whelan 1972, Lammers 1967) . There are numerous
disadvantages, however, in its application to routine
water analysis. Large volumes of water are required
and samples are susceptible to contamination (Batley
and Gardner 1977, Abdullah'et al 1976 ) . Separation -46- is achieved as a function of centrifuge speed, time, and particle density. Fine grained organic material can have a density close to that of water, thus making separation difficult even at high speeds
(Gibbs 1974). Additionally the equipment required is very expensive (Perhac and Whelan 1972). Thus filtration is the only technique generally in use at present (Cheeseman and Wilson 1973, Stiff 1971b).
The separation achieved by filtration is not absolute, and depending on the pore size used, undissolved material such as colloids may pass through the filter. Many different types of filter have been used, thus care must be exercised in the comparison and interpretation from the literature of results for "dissolved" metal species obtained by different workers (Wilson 1976) .
A number of workers have recommended the use of membrane filters with a pore size of 0.45 pm to distinguish particulate from "dissolved" species
(Parker 1972, Riley el-~ ' 1975, Strickland and Parsons 1967, United States Environmental
Protection Agency 1971). It has also been recom- mended (American Public Health Association 1971,
Wilson 1976) that the terms "filtrable" and "non- filtrable" be used rather than "dissolved" and
"undissolved". This allows recognition of the fact that species which are not truly dissolved such as finely dispersed colloids can pass through -47-
the pores of a 0.45 pm membrane filter (Hem 1972a) .
A number of these colloidal species are thought
to have a significant effect upon metal speciation.
Sorption onto colloidal hydrous iron and manganese
oxides is thought to be very important (Jenne 1968),
and metal-clay colloid ion exchange reactions and
sorption onto humic acid-clay -colloids may also be
important processes controlling speciation (Guy et al
1975).
2.3.1 Types of Filters
In selecting a filter the following criteria
should be satisfied (Riley el-al l«p5-):-
(i) the filter should have a uniform and
reproducible pore size;
(ii) the rate of filtration should be high and
the filter should not clog easily;
(iii) the non-filtrable material should not
penetrate into the filter but should be
retained on the surface so that it can be
removed easily;
(iv) the filter should not adsorb trace elements;
(v) the filter should contain no loose fibres since
these may contaminate the water or the non-
filtrable material.
Common membrane filters consist of discs of
incompletely cross-linked polymers of partially -48-
substituted cellulose acetate or nitrate (Cheeseman
and Wilson 1973). The disc is approximately 0.15 mm
thick and resembles an intricate cellular network
of pores (Gibbs 1974). Pore sizes show a high"
degree of uniformity within a filter and between
filters. Despite this, filters of the same nominal
pore size have been shown to vary in speed of fil-
tration and particulate retention (Wagemann and
Brunskill 1975). The pore volume is about 80% of
the total filter volume so that relatively rapid
filtration rates are possible. An alternative to
this type of membrane is the Nuclepore type filter, made of polycarbonate. In these filters, the pores
follow a straight path passing through the filter
disc. These filters are thinner than cellulose
ester membranes. Nuclepore filters are lighter
than their cellulose counterparts, and thus more
suitable for very low concentrations of suspended matter (Gibbs 1974). However, because of the straight pore pathway, they clog rapidly which makes them unsuitable for use with river waters.
To obtain practically desirable rates of fil-
tration, it is advisable to filter under vacuum or under pressure. The latter offers advantages in terms of speed, particularly with samples with a high suspended solid concentration (Batley and
Gardner 1977). However, recent work has indicated that depending on the system used, the problems -49-
of sample contamination can be extreme with pressure
filtration cells (Mill 1976, Whiting 1979).
With either vacuum or pressure filtration, low
pressures should be used. Filters of 0.45 pm pore
size retain all phytoplankton and most-bacteria,
and high pressures can cause rupture of phytoplank-
ton cells and release of heavy metals to the filtrate
(Batley and Gardner 1977). Changes in speciation can also result due to an increase in the dissolved organic content of the water.
Membrane filters are chemically quite stable and may be treated with a number of reagents to
remove contaminants (Cheeseman and Wilson 1973).
Continued filtration can lead to clogging of the filter pores and retention of particles smaller than the nominal pore size of the filter (Sheldon and Sutcliffe 1969). This, and the resulting reduction in filtration rate,can be overcome by stirring or frequent replacement of the filters
(Batley and Gardner 1977).
Whatman glass-fibre filters are often employed as an alternative to membrane filters. These are discs consisting of an intermeshed network of glass fibres. These filters remove particles throughout their thickness rather than on the surface (Cheeseman and Wilson 1973). Although this leads to more rapid filtration, removal of the material collected by the -50-
filter is difficult. The Whatman GF/C type filter
has an effective pore size of 0.5 - 1.5^pm. They
are cheap and convenient to use and have been recom-
mended by Strickland and Parsons(1967). However,
preliminary studies by the Water Research Association
have'indicated that a 0.5 ^pm membrane removes apprec-
iably more iron from Thames river water than a GF/C
filter (Cheeseman and Wilson 1973). This indicates
that fine particulate matter, such as aggregated
Fe colloids are passing through the coarser pore
sized GF/C filter into the filtrate. A glass-fibre
filter of effective pore size of 0.7 jam (GF/F) can
also be employed, and has been reported to have the
advantage of higher filtration rates over membrane
filters (Cheeseman and Wilson 1973). Glass-fibre
filters contain no binder or organic materials, and
can withstand most laboratory reagents and temper-
atures up to 500°C. This facilitates cleaning to
remove residual contamination and dissolution of
materials retained by the filter.
2.3.2 Contamination and Adsorption by Filters
Metallic impurities within membrane and glass-
fibre filters can be sufficiently high to cause
problems in trace metal analysis at the yg/1 level.
Spencer and Mannheim (1969) have reported that the
principal contaminants of Millipore filters were
Al, Cr, Cu, Fe, and Zn. Additionally Zirino and -51-
Healey (1971) found that relatively large amounts
of Zn were leached from Millipore and Gellman filters .
This was eliminated, however, by pre-treatment with
one litre of 3% (v/v) nitric acid followed by
deionised-water. Mill (1976) reported extremely
high 'levels of Zn (approximately 30,000 ppm) in
GF/C filters which were totally digested in hydro-
fluoric acid. However, aliquots of deionised water
passed through GF/C filters pre-washed with acid
have shown little contamination. Similarly results
for acid washed Sartorius membrane filters obtained
during this study have revealed little significant
contamination, (see Chapter 5).
Loss of trace metals by adsorption onto filters
has also been reported (Batley and Gardner 1977,
Marvin et al 1970). Gardiner (1974b) found that 1%
of the Cd was lost from 25 ml of tapwater irrespective
of the initial Cd concentration. Adsorption losses
are a particular problem with glass fibre filters.
Owing to their structure, a large surface area of
glass is presented to the filtrate. This area contains
an enormous number of reactive sites which facilitate
the removal of trace metals from solution by adsorp-
tion. Pre-treatment of the filter for example by
silanisation, may overcome this problem.
2.4 Analysis of Filtrate
With the possible exception of anodic stripping -52-
voltammetry, instrumental methods for the analysis
of trace metals in water require an initial precon-
centration step, as concentrations encountered
naturally are usually below instrumental detection
limits. Four concentration procedures are generally
available for atomic absorption analysis! chelation-
solvent extraction, chelation-ion exchange, evapor-
ation, co-precipitation (Watling 1974).
2.4.1 Chelation-Solvent Extraction
Solvent extraction is that process whereby two
immiscible liquids are brought into contact so as
to effect a transfer of one or more elements from
one liquid phase to the other (Mulford 1966).
Metallic species are usually more soluble in aqueous
media than in organic solvents due to their ionic
nature. To extract a metal ion into an organic phase,
therefore, it is first necessary to convert the ion
into an uncharged species. Most metals will form
stable neutral and extractable complexes with organic
chelating agents. The organic solvent must completely
dissolve the metal chelate and be immiscible with the
sample solution (Watling 1974).
Solvent extraction techniques are useful when
applied to water analysis, in both concentrating
specific metals and removing them from interfering
matrices, for example major salts in sea-water (Brooks
et al 1967, Joyner and Fihley 1966, Olsen and Somerfield -53-
1973). A further advantage of this method is the
increased signal obtained when an organic solvent
is directly aspirated. This enhancement can be of
the order of three to five times depending on the
solvent, and is due to increased nebulizer efficiency
(Parker 1972).
Although a wide range of-organic chelating
agents are available, ammonium pyrollidine
dithiocarbamate (APDC) and sodium diethyldithio- carbamate (SDDC) have been most commonly used.
Methylisobutyl ketone (MIBK) is the most commonly used solvent as it can be aspirated directly into
an AA spectrophotometer (Kinrade and Van Loon
1974).
A wide range of metals have been extracted using the APDC - MIBK system, for example Cd, Cr,
Co, Cu, Ni, and Pb from freshwater (Brown et al
1970), Co, Cu, Fe, Pb, Ni, and Zn from saline waters
(Brooks et al 1967), As, Bi, Fe, Se, Tn, and Zn,
from prepared solutions (Mulford 1966), and Cd and
Pb from tapwater (Cockcroft et al 1977). Additionally
Nix and Goodwin (1970) have used SDDC - MIBK to ex-
tract Cu, Co, Fe, Mn, Ni, Cr, Pb, and Zn, from
reservoir and lake waters.
The instability of a number of APDC-metal chelates in solution, particularly that of Mn, has been reported (Brown et al 1970, Jenne and Ball 1972, -54-
Olsen and Somerfield 1973, Kinrade and Van Loon
1974) . Thus it has been recommended that analysis for Mn, at least, should be conducted immediately after extraction (Nix and Goodwin 1970). Olsen and Somerfield (1973) showed that evaporation of the MIBK extract to dryness followed by re-solution with hydrochloric acid and acetone stabilised the extracted chelate for at least two weeks.
Metal complexes can also be extracted into chloroform (Adam et al 1972, Oki and Terada 1974,
Lakanen 1966, Watling 1974). The organic phase can be evaporated and the residue destroyed by the
addition of acid. In this way the sample extracts
can be stored in an inorganic state pending
analysis (Watling 1974).
A number of workers have reported interfer-
ences in the extraction of trace metals due to organic compounds occurring in polluted and in
unpolluted waters. Joyner and Finley (1966),
using SDDC, reported that at the natural pH of
sea-water, recovery of the organically bound
portions of Fe and Mn could not be guaranteed.
Florence and Batley (1976) reported similar findings
for Pb and Zn extracted from sea-water by APDC.
Using artificial solutions, a number of other
interferences have been reported (Pakalns and Farrar
1977). For example, soap was found to interfere in -55-
the extraction of Cu using APDC-MIBK• EDTA at a
concentration of 25 mg/l completely prevented the
extraction of Ni and Fe by APDC as the EDTA-chelate
formed was too strong. However, addition of
aluminium nitrate overcame this problem for Mn,
Zn, and Co. In experiments on natural waters, the
addition of aluminium nitrate and a reaction time
of twenty minutes at pH 4.6 was found to release
all the metals of interest (Cu, Pb, Zn, Cd, Co, Fe,
and Mn) from any organic chelates present and to
make them available to form extractable APDC
complexes (Pakalns and Farrar 1977). Kinrade and
Van Loon (1974) have also reported interferences
due to biodegradable detergents.
2.4.2 Chelatinq-ion Exchange Resins
Chelating resins have been used extensively
for the concentration of trace metals from sea-
water. Riley and Taylor (1968a) describe the
concentration of metals from sea-water and distilled
water using Chelex-100 and Permutit S1005. They
give retention and recovery data for 29 elements,
and suggest that the prime advantage of the ion
exchange methods lies in the high concentration
factors obtainable.
Elderfield (1971), using 10 litre samples,
employed Chelex-100 resin to concentrate metals
in estuarine samples prior to analysis by AAS. -56-
Abdullah and Royle (1972b) used Chelex in the Ca- form with solutions buffered at pH 4-8 in conjunc- tion with pulse polarography to determine concen- trations of Cu, Pb, Cd, Zn, Ni, and Co in samples of sea-water, freshwater and synthetic mixtures.
They 'checked recoveries from Chelex using water stripped of metals by passage through the column and spiked with ionic solutions of the various metals. They recorded complete recovery of the metals by this technique.
Florence and Batley (1976), however, have shown conclusively that a significant proportion of the heavy metals in sea-water exist in a form not retained by Chelex resins or extracted by APDC when concentration procedures are performed at pH 4-8. Analysis by anodic stripping voltammetry
(ASV) suggested that the unavailable metals were adsorbed on,or occluded in^organic or inorganic colloidal particles. In conjunction with this, the solvent extraction technique was found to be more efficient than Chelex-100 in recovering trace metals from sea-water. This was probably due to the solubility of the organic colloidal particles in the MIBK solvent. Gentle boiling of the sample adjusted to pH 0.7 before concentration by the resin or APDC, was found to release the bound portion of the metals.
As a result of this work Florence and Batley -57-
(1976) criticize the use of ionic spikes in estimat-
ing the recoveries of extraction procedures. They
point out that the metal may not exist in the purely
ionic form in the sample, but may be in a complexed
or colloidal form, which will not equilibrate with
the ionic spike at the time of the separation ex-
periment.
A similar study conducted by Abdullah et al (1976 ) confirmed the results of Florence and
Batley (1976). Centrifugation showed that the
metal liberated by acid digestion prior to concen-
tration by Chelex-100 was associated with colloidal
and fine particulate matter capable of passing
through a 0.45 ym filter. The portion of the
metals sorbed to these colloids and fine particu-
lates was not affected or removed by the resin^
2.4.3 Evaporation
This method is simple and requires a minimum
of reagents, and involves concentration of the
sample by reduction of its volume by evaporation.
The method has been employed in river water analysis
by Angino et al (1969).
It has a number of disadvantages, however!
a) It is a slow method, often requiring 1-2
days to evaporate a litre sample. This gives
rise to considerable risk of contamination. -58-
b) If large quantities of dissolved solids are
present in the sample, precipitation can occur
as the volume decreases. This problem can be
overcome by evaporation to dryness and re-
dissolving the salts with dilute acid and
making up to a known volume. Solid particles
in the sample solutions can also cause light
scattering interferences during flame AAS
analysis.
c) The salt concentration can be high and cause
interferences in AAS analysis. Nebulizer
efficiency can be reduced with very high
total dissolved solid concentrations, and
in extreme cases blockage of the nebulizer
may occur (Parker 1972).
2.4.4 Co-Precipitation
Trace metals have been preconcentrated from
sea-water samples using co-precipitation with ferric
hydroxide (Burrel 1967) and sodium carbonate (Joyner
et al 1967). Both methods involved further separa-
tion from the precipitating agent prior to analysis.
Joyner and Finley (1966) investigated trace metal
concentration by co-precipitation using Mn-hydroxide
as the carrier. They reported interference when the
redissolved precipitate was aspirated directly into
the flame. Co-precipitation followed by solvent
extraction with SDDC/MIBK was also investigated, -59-
but the results indicated that single step solvent
extraction (using SDDC/MIBK) was more efficient
at concentrating the trace metals than the two step
procedure. Additionally, co-precipitation is time
consuming, tedius and prone to contamination
(Florence and Batley 1976).
2.5 Analysis of Suspended Particulates
There are a number of approaches to the ex-
amination of the solid material collected on a
filter membrane. Acids of varying strength can be
used to leach heavy metals from the particulate
material. Dilute acid leaches, such as 0.1 M
hydrochloric acid (Foster et al 1978), or 0.5 M
hydrochloric acid (Thorne 1978) can be used to
recover exchangeable or non-residual metals from
the particulate. Gibbs (1973 and 1977) used a
sequence of leaching agents to partition the metals
amongst a number of phases, for example; ion
exchangeable, associated with metallic (Fe, Mn)
coatings, associated with organic matter, and
residual metals in crystal lattices.
The total concentration of heavy metals can
be obtained by either wet or dry ashing techniques.
The former technique was used by Rantala and Loring
(1977) to decompose the suspended matter collected
on Nuclepore filters using a mixture of aqua regia
and hydrofluoric acid in a closed Teflon vessel. -60-
Redistilled concentrated nitric acid may also be used (Kopp and Kroner 1967). Examples of dry ashing include work by Angino et al (1974) who analysed the residue by emission spectrography.
Montgomery and Santiago (1978) analysed for Zn and Cu in particulate matter by dry ashing at
400°C and dissolving the residue in concentrated hydrochloric acid. The solutions were then ana- lysed by AAS. With both "total" methods, it is necessary to know the metal content of the filter.
This can be considerable and can vary between filters. Additionally, loss of metals by volat- ilisation can occur using dry ashing techniques.
An alternative to chemical attack is to use
X-ray fluorescence for total metal determinations.
Elder et al (1976) used this method to determine
iron concentrations in freshwater suspended matter collected on Millipore filters. The method has also been applied to marine samples (Cann and
Winter 1971).
An important facet of the study of suspended matter is the mineralogy of the material present
(Angino et al 1974) . This can be determined by
X-ray diffraction techniques. Wood (1978) found
that the mineralogy of the bedrock, soils and
alluvium over which a river flows is only reflec-
ted to a limited extent in the suspended solids. -61-
He concluded that controls on the suspended solid
mineralogy were, i) ratio of the ground-water
contributions to surface run-off contributions to
river flow, ii) the rate of reaction of soil and
bedrock to rainfall, iii) the preferential settling
of platy grains in quiet stretches of water, iv)
precipitation of material from solution. It is
clear from this work that study of the mineralogy
of suspended sediment is important for a full under-
standing of the geochemistry of the associated
metals.
2.6 Forms of Metals in Solution
Metals can exist in rivers in a large number
of different chemical and physical forms, e.g.
dissolved^colloidal, undissolved, chelated with
organic ligands etc. It has become well established
in recent years that in order to understand the
behaviour of a metal in a river, that is, the
factors affecting its transport, removal from the
water body and its toxicity to aquatic life, a
knowledge of these various forms is essential
(Florence and Batley 1977, Durum and Hem 1972,
Andelman 1973, Stumm and Bilinski 1973).
2.6.1 Classification of Metal Species
Several schemes of classification of metal
species exist and that of Stumm and Bilinski (1973),
is given in Figure 2.1. A similar scheme for copper -62-
Flgure 2.1 Types of Metal Species in Water
Metal ' Range of diameters Examples* species (pn)
24 34 Free CU(H20)6 , Fe(H20)6 . metal ions
24 Simple uo2 , vo3~. radicals
w 24 2 Inorganic Cu2(0H)2 , Pb(C03)2 ", CuC03°, ion-pairs ffl + and < AgSH°, CdCl , C0OH*, Zn(0H)3~. complexes u « w n Organic 0.001 A •4 Me - 00CR *. CH. C —< O complexes, « chelates & 0) HgR < M < 2* H2N. compounds m Xu >« on >4 W t* o NH. < a \ < M 0"C CH/. tn «OS Metals Me - humic/fulvic acid polymers. bound to x high W molecular 0.01 weight X organic materials Highly- FeOOH, Mn (IV) hydrous oxides, dispersed colloids
I n+ Metals 0.1 Me.aq , Men(OH) Me C03, sorbed on colloids etc. on clays, FeOOh, organic colloids.
Precipitates, Cu C03, ZnSi03, CdS in FeS, mineral particles PbS. organic particles Metals Metals in algae. present in live & dead biota
* Me » metal, R «= alkyl (based on S^^-n Bilinski 1973) -63-
has been proposed by Kamp-Nielsen (1972). A large
body of literature now exists concerning trace
metal speciation in water, and there have been a
number of recent reviews dealing with various aspects
of the subject in fresh water, estuarine and sea-
watet. (Florence and Batley 1977, Wilson 1976,
Jones 1978). In addition a number of books dealing
with the chemistry of metals in water have relevant
chapters (Rubin 1974, Krenkel 1975, Singer 1973).
Hem (1970) also outlines the aqueous chemistry of
the more uncommon metals.
There have been essentially two major approaches
to the problem of identifying dissolved metal species
in water, namely theoretical by the use of chemical
modelling, and analytical, by attempts to make
measurements of the concentrations of individual
species present. A number of studies have used a
combination of the two (e.g. Gardiner 1974a, Stiff
1971b).
2.6.2 Chemical Modelling
In principle it is possible, given the total
metal concentration, and a number of chemical
parameters e.g.t stability constants of aqueous
species, solubility products of insoluble species,
pH, concentrations of inorganic and organic ligands
etc., to calculate both the concentrations of all
the dissolved metal species present and the nature -64- of any insoluble species in equilibrium with the solution.
Many relevant papers involving computations of this sort for a variety of metals in a number of different systems of varying complexity have been published (see Wilson 1976). Several comp- uter programmes are available -to cope with the calculations (e.g. Truesdell and Jones 1974, Perrin and Sayce 1967, Morel and Morgan 1972). The methods and principles have been described by Stumm and
Morgan (1970) and for simpler systems involving
Eh and pH by Garrels and Christ (1965). A recent paper by Vuceta and Morgan (1978) gives an example of a particularly complex study involving four major cations, nine trace metals, three types of adsorbent surface of varying surface area, five organic ligands and pH. However)even in view of the complexity of such models, the results give only an approximate indication of the species likely to be present. The equilibrium distribution model will be affected by the choice of metals and ligands inserted into the calculation (Vuceta and Morgan
1978). Additionally, the stability constants for all the complexes and chelates and solubility product data for solids are not always available and are often uncertain (Wilson 1976, Truesdell and Jones
1974, Vuceta and Morgan 1978).
Finally, owing mainly to the restrictions -65-
imposed by considering a limited number of variables
in a model, several factors, known by experiment to
be important, have often been ignored. These include
processes such as exchange and adsorption to surfaces
(particulate or bed sediment) (Leckie-and James 1974) ,
the effects of biota in either releasing metals to or
removing them from solution (Lee and Hoadley 1967),
and particularly the complexation of metals by organic
compounds (Wilson 1976, Reuter and Perdue 1977).
2.6.3 Direct Measurement of Metal Species
The other approach to the problem of metal
speciation has been to attempt direct measurement
of the concentrations of the various species thought
to be present. Again a vast literature exists on
this subject alone, and the review by Florence and
Batley (1977) is particularly useful. A large
variety of techniques exist, and some selected
examples are given below.
Several authors have used methods such as di-
alysis, ultrafiltration, gel filtration chromatog-
raphy and ion exchange resins to separate "ionic"
forms from metals associated with colloidal material.
For example, Bender et al (1970) and Means and Crerar
(1977) have demonstrated the use of gel filtration
chromatography to isolate the soluble metal bearing
organic fractions of sewage effluent and river water
respectively. Using humic materials separated from -66-
lake, river and sea-water and gel filtration chromat- ography, Mantoura et al (1978) have determined con-
ditional stability constants for a number of metal- humic complexes.
Mill (1976) and Ramamoorthy and Kushner (1975)
have used ultrafiltration to separate dissolved macro molecular organic species from river water, and
Florence and Batley (1976) have proposed the use of
Chelex-100 ion exchange resin to separate colloidally bound metals. Relatively large volumes of water are
required in gel filtration and ultrafiltration, often making metallic contamination a considerable problem
in the application of these techniques (Florence and
Batley 1977, Mill 1976).
Ion selective electrodes (ISE) which measure
free hydrated metal ions but do not respond to complexed forms have also been used (Ramamoorthy
and Kushner 1975, Stiff 1971b). Stiff (1971b) has developed an analytical scheme to determine the chemical forms of copper in polluted water based on the use of the copper ISE. A number of diffic- ulties exist, however, in the use of ISEs, in terms of the reproducibility of the measurements, the stability of the electrode and reference electrode, and the limitations imposed by the measurable con- centrations (Minear and Murray 1973).
The most commonly used electrochemical technique -67-
in speciation studies is anodic stripping voltammetry
(ASV). There are numerous reports in the literature of the use of this technique usually combined with various chemical pretreatments (e.g. Gardiner and
Stiff 1975, Florence 1977, Batley and Florence 1976) , or theoretical chemical models (e.g. Gardiner 1974a,
Stumm and Bilinski 1973) to further elucidate the
nature of the metal species present.
Florence (1977) has applied a comprehensive scheme of analysis to samples of fresh water using differential pulse anodic stripping voltammetry
(DPASV) and a number of chemical pretreatments to yield seven groups of metal species. However, as
the author points out, there are disadvantages in
the method, namely that the various operationally defined metal classifications given by his analyt- ical scheme cannot be identified with exact chemical species in the sample. In common with all experi- mental measurements of speciation, some disturbance of the equilibrium of the species within the sample is also inevitable. The possibility of intermetallic compounds forming in the amalgam of the electrode, which affects the stripping characteristics is a special problem associated with ASV measurements
(Laitinen 1975, Gardiner and Stiff 1975).
As mentioned, contamination problems in practical speciation studies are extreme, with the purity of -68-
reagents and apparatus being critical (Florence and
Batley 1977). Samples usually have to be stored
without preservation for varying periods of time
before analysis, and this can cause loss of trace
metals by adsorption to container walls and changes
in chemical speciation (Benes and Steinnes 1975).
For speciation work Florence (1977) and Batley
and Gardner (1977) have shown that storage at 4°C
in high density polyethylene or Teflon bottles is
the preferred technique.
As can be seen from Figure 2.1 a large number
of dissolved species can exist. The distribution
of a metal amongst the various species is the result
of interactions between the available ligands present,
both organic and inorganic, potential adsorbent
surfaces e.g. organic colloids, colloidal iron and
manganese oxides, clay minerals etc.
Types of metal species can be broadly separated
into two major groups, dissolved inorganic species
and dissolved metal-organic species. The volume of
literature on the subject is immense; selected
examples to illustrate the main points are given
below.
2.6.4 Dissolved Inorganic Species
Within this category are included species such 2 + as hydrated metal ions, e.g. Cu(H90)A , and in- -69- 2 + organic ion pairs and complexes e.g. Ci^fOH^ >
CuCO°.
Florence (1977) has concluded that the principal forms of Cd and Zn in fresh water are as ionic labile forms for Cd and ionicj^and stable inorganic complexes for Zn. These findings confirm the work of Gardiner (1974a), who concluded that a large pro- portion of the Cd present in fresh water was in the 2 + form of the free hydrated ion Cd aq. Its concen- tration in this form would be reduced in the pres- ence of strong complexing agents. The results of these experimental studies can be compared with the model proposed by Vuceta and Morgan (1978). The model indicates that most of the dissolved Cd will
2 + be as Cd aq ions, and that given the correct alkalinity and pH solid cadmium carbonate will precipitate, as shown experimentally by Gardiner
(1974a). Hem (1972a) concluded that cadmium car- bonate would be the limiting solubility species for Cd. Vuceta and Morgan (1978) have concluded that Zn will exist in solution predominantly as free hydrated Zn ions, though with an increase in adsorbent surface area and organic ligand concen- tration, some adsorption and complexation of Zn will occur.
Florence (1977) found that Pb occurred mainly as non-labile inorganic complexes, and this again -70- compares well with the chemical models of Vucetta
* and Morgan (1978) and Rickard and Nriagu (1978).
These latter authors concluded that lead carbonate would dominate the inorganic chemistry of Pb, though they pointed out that their model "played down" the dffects of adsorption by organic and mineral particulates. Vucetta and Morgan (1978) suggested that the distribution of Pb between dissolved and adsorbed phases would be dependent mainly on the availability of the surface area of adsorbant.
Hem and Durum (1973) also concluded that the carbonate or hydroxide of Pb would impose an upper limit to its solubility. However, in a later paper
(1976) Hem also shows that the concentration of dissolved Pb can be maintained well below that pre- dicted on the basis of equilibrium solubility products by ion exchange with clays.
Many metals can also exist in more than one oxidation state. Theoretical studies allow the prediction of stable oxidation states of metals in a given system, however there have been few studies on actual river water (Wilson 1976). The redox potential and pH will also affect the speciation of trace metals in solution. Theis and Singer (1973) have reported that ferrous forms of Fe can be stabilised by organic materials such as humic acids in water. -71-
2.6.5 Metal-organic Species
There has been much discussion on the occurrence
and extent of metal organic complexes in water (Stumm
and Bilinski 1973, Reuter and Perdue 1977), and the
subject has been examined in detail by Reuter and
Perdue (1977) and Singer (1973).
Two types of species can be distinguished:
a) truly dissolved metal complexes and chelates,
e.g: those with citrates, EDTA and NTA.
b) metal-organic associations with high molecular
weight materials of the humic acid type.
A number of theoretical studies have included
compounds such as NTA and citrate within their
calculations. These have indicated that complexes
might exist and that they could exert a considerable
influence on metal speciation (Vucetta and Morgan
1978, Morel et al 1973, Lerman and Childs 1973).
From experimental studies, Stiff (1971b) has
quoted stability values for Cu-amino-acid chelates
in river water, though his results are inferred
rather than direct observations. The presence and
biodegradation of metal chelates (Swisher et al
1973) and the remobilisation of heavy metals from
sediments by NTA and EDTA have been demonstrated
experimentally (Banat et al 1974, Barica et al
1973). The extent to which the results of the -72-
above studies can be extrapolated to the natural
environment is unknown.
The pH of the water is important, as protons
can compete with the metals for compounds such as
NTA; the amount of metal decreases markedly with
pH decreasing below neutral. Increased pH may also
decrease the amount of metal chelated due to increased
competition by 0H~ ions with the chelator. Phosphate,
sulphate, carbonate, silicate, sulfide etc. will all
compete with a chelator depending on the solubility
products of their corresponding metal salts (Swisher
et al 1973). Many natural organic chelators are
also present in water and these in turn will compete
with compounds such as EDTA and NTA for available
major and trace metals.
Lerman and Childs (1973) have studied the
behaviour of NTA and citrate in a water of "average"
river water composition using thermodynamic model-
ling. They found that strong complexes are formed
with heavy metal ions, and weaker complexes with 2+ 2 + the major cations Ca and Mg . The model predicts
that all the available Co, Fe, Pb, Ni, Cu, and Zn
will be complexed, and when no more of these metal
ions are available, then complexes with Ca and Mg
will be formed. Complexing of Ca would become
significant at total ligand concentrations of 2mg/l
to 15 mg/l. Thus the effect of NTA and similar -73- compounds would be to seriously perturb the natural ion balance in river waters. However, with the biodegradation of these compounds, it is thought that a return to natural equilibria would be ~ achieved.
Of the second class of compounds it is well established that many metals can form associations with high molecular weight organic species (Gamble and Schnitzer 1973). A number of conditional stability constants for metal organic complexes of the humic acid type have been experimentally determined (Mantoura et al 1978, Florence and
Batley 1976).
On the basis of such data, Mantoura et al
(1978) have calculated that most of the Cu present in fresh water will be complexed by humic materials.
This would confirm earlier work by Florence (1977).
Benes et al (1976) who indicated that Cu, Zn and Co were strongly complexed by humic acids, and Gardiner
(1974a) formed a similar conclusion for Cd in fresh water. The stability of ferrous Fe in solution by fulvic acid has also been demonstrated. Stumm and
Bilinski (1973) have pointed out that although there is circumstantial evidence (of the kind quoted above) for the existence of soluble metal chelates in natural waters, there is no direct proof.
Care must be exercised in the interpretation -74- of experimental results and theoretical calculat- ions, that full allowance is made for the compet- ition between trace metals and Ca and Mg for the organic ligand. Stumm and Bilinski (1973) argue that the functional groups typically encountered
in dissolved organic substances, e.g. -COOH, -NH2,
-OH, -SH show little specificity for individual
metal ions. Hence}the co-ordination tendencies of 2+ 2+ most ligands will be satisfied by Ca and Mg usually present at concentrations at least a thousand fold larger than those of the trace metals or of the chelate forming substances.
Therefore, although it is well established that heavy metals can form complexes with high molecular weight organic substances, it does not necessarily follow that these complexes will form under con- ditions typically encountered in natural waters.
More recently Mill (1976) has separated colloidal and macro-molecular organic species from river waters using ultra-filtration. He was able to show that with the exception of Fe, the major proportion of the heavy metals in the waters was associated with low molecular weight organic fractions (Mol wt <500) and small organic and inorganic species. Preliminary elemental and structural analysis of the macromolecular materials collected on the filters indicated that they were similar to soil humic substances. Chemical -75-
analysis revealed that the lighter elements, such
as the alkali metals and Al were the principal metals
associated with these materials and only trace con-
centrations of the heavy metals were found.
2.7 Levels of Heavy Metals in Stream Sediments
Regional geochemical reconnaissance maps based
on multi-element analysis of tributary drainage
sediments have been applied to problems in agri-
culture, fundamental geology, pollution studies
and mineral exploration (Webb et al 1978). It has
also been suggested that stream sediment concen-
trations of heavy metals may provide an indication
of the long term heavy metal status of the associated
waters (Aston et al 1974, Aston and Thornton 1977).
As stream sediments can act as both sources
and sinks for heavy metals, it is important to have
an understanding of the location of heavy metals
within sediments, and the processes which control
removal from or release to the water body.
An indication of the frequency of occurrence
of trace metals in stream sediments throughout
England and Wales is given in Table 2.2. The data
for this table were compiled from the Wolfson
Geochemical Atlas of England and Wales. Table 2.2 The Occurrence of Metals in Stream Sediments of England and Wales
In yig/g Stream Sediments data i 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 99%
Li 0.1 6 10 17 23 28 33 38 45 55 79 97 137 Mg% .01 1.48 1.80 2.04 2.21 2.38 2.60 2.91 3.32 3.82 4.72 5.57 7.49 Al% .01 2.32 2.81 3.36 3.81 4.21 4.58 5.05 5.61 6.42 7.57 8.119 9.84 Sl% 21.04 23.44 25.82 27.41 28.64 29.65 30.76 32.0 32.81 34.36 35.4 36.92 K% 0 .39 .478 .607 .685 .734 .855 .944 1.015 1.148 1.326 1.495 2.004 Ca% .01 .31 .38 .51 .65 .85 1.15 1.62 2.60 4.18 6.83 10.2 20.01 Se .01 .7 1.2 2.4 3.5 4.3 4.9 5.0 6.5 7.7 10.00 11.9 16 V .1 8 13 19 25 31 38 45 52 .62 70 88 108 Cr .1 13 19 25 30 34 40 44 50 56 66 74 98 Mn .1 167 212 279 331 385 444 521 628 818 1324 2080 5346 Fe% .01 1.58 1.79 2.10 2.36 2.59 2.82 3.09 3.44 3.82 4.42 4.93 5.95 Co .01 1.1 2.1 3.9 5.3 6.7 8.2 9.9 11.6 14.1 18.4 23.4 48.4 Ni .1 4 5 9 13 15 19 22 27 32 40 46 60 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 95% 99%
Ca .1 5 6 9 12 14 17 19 22 25 31 40 72 Zn .1 41 49 59 79 80 91 104 118 141 182 228 419 Ga .01 1.5 2.3 3.5 4.4 5.1 6.2 7.2 8.4 10.2 13.6 16.9 21 As .1 2 3 4 6 8 9 10 12 15 . 20 27 66 Sr .1 17 21 27 31 36 42 48 58 74 100 134 265 Mo .01 .3 .4 .6 .7 .8 .9 1.0 1.1 1.3 1.7 2.1 3.9 Sn 0 2 3 4 5 9 22 1059 Br .1 92 109 132 149 164 181 198 216 242 196 382 946 Pb .1 10 13 17 20 23 26 30 36 46 68 99 259
Data derived from Webb et al 1978 Explanation - e.gj 5% of sediments have 6 ug/g Li or less and 1% have 137 pg/g Li or more. -78-
2.7.1 Seasonal Variations in Metal Concentrations in
Sediments
There have been relatively few reported studies
concerning either long or short term temporal var-
iations in stream sediment composition. Two early
studies by De Grys (1963) and Govett (1960) indi-
cated considerable seasonal variations in the con-
centrations of heavy metals in drainage sediments.
These studies were, however, conducted in the
Chilean Andes and Northern Rhodesia respectively;
two areas with extreme climates. The applicability
of the results to the temperate climate of Britain
is therefore doubtful.
Studies on the Cu content of stream sediments
in temperate regions of Canada indicated that there
was no significant variation in concentration on
a seasonal basis (Hoffman and Fletcher 1972, Barr
and Hawkes 1963). Chork (1977) studied the varia-
tion in stream sediment concentration of a number
of metals in background and anomalous streams.
Two-way analysis of variance was used to determine
whether there was any significant variation in
metal contents between sampling times and between
sample sites. It was concluded that variations
due to seasonal effects were slight and insigni-
ficant compared with the regional variation.
Fanta (1972) studied the problem on a regional -79- basis in North Wales. He chose 23 sites in seven streams, which were sampled at monthly intervals for a year. Comparison of the mean monthly metal concentrations for all the sites showed that Mn, Ni, and Co varied seasonally with an autumn maximum and winter and spring minimums. Cd, Zn and Pb showed great fluctuations in concentration, which could not be correlated with seasonal effects, and Cu and
Fe remained constant. However in a more detailed study, involving intense sampling of two tributaries and similar methods of data analysis, clear seasonal patterns in metal levels could be distinguished.
Fanta (1972) pointed out that sampling frequency is an important consideration in seasonal studies.
Infrequent sampling will not detect short term temporal variations, whereas long term variations cannot be identified with certainty unless the study period is long enough to include several episodes.
More recently Aston and Thornton (1977) have measured the trace element composition of stream sediments from eight tributaries in four catchments in Cornwall at monthly intervals for a year. They also compared mean monthly metal concentrations for each tributary. In all four catchments considerable variations occurred, on a temporal basis, in the concentrations of all the trace elements studied, with the greatest variations being found in miner- -80-
alised tributaries. The variations were thought
to be related to changes in bed load resulting from
fluctuations in weathering and changes in the grain
size distribution of the sediments.
In a study on a small contaminated tributary
in Wales, Lewin and Wolfenden (1978) were able to
show a marked seasonal variation in Pb concentration
in the sediments. They found a considerable increase
in metal concentration at a time of low summer flow
which also coincided with an increase in the organic
content of the sediment. A strong correlation between
sediment organic content and Pb concentration through-
out the year was also observed. It would seem that
the Pb was being fixed by accumulating organic
matter by adsorption and/or chelation anchor by
biotic activity in the undisturbed sediments. In-
creased metal concentrations with increased sediment
organic content at a time of low summer flow were
also noted by De Grys (1963).
2.7.2 Mode of Occurrence of Heavy Metals in Stream Sediments
Important modes of occurrence of trace elements
in stream sediments include the following:
1) Occurrence as a major element in a trace mineral
e.g. Zn in sphalerite, Pb in anglesite (PbSO^).
2) Occurrence as a trace constituent in a mineral
inherited from weathered local parent material -81-
e.g. Cu in biotite, Zn in magnetite.
3) Occurrence as a trace constituent in the lattice
of a mineral formed during weathering or occluded
as a trace element in such a phase, or adsorbed ~
in such a mineral and covered by further pre- —
ci'pitation e.g. Zn in the octahedral sites of
montmorillonite clays or Cu in Fe and Mn coat-
ings and encrustations.
4) Occurrence due to adsorption onto the surface
of an iron or manganese oxide, colloidal clay,
oxide or organic particle.
Of these four occurrences, the latter two are
of particular importance to the environmental
chemistry of heavy metals. Elements held in sites
listed under (4) above are very sensitive to changes
in the composition of the enclosing solution, and
may be released from a river sediment to the water
body under certain conditions (Malo 1977). The
availability of metals in (3) above will be con-
trolled largely by the properties of the host
mineral. However, because these minerals are often
fine grained with imperfectly formed crystal lattice
structures, elements contained within them can be
available to surrounding solutions (Rose 1975).
2.8 Chemical Analysis of Stream Sediments
2.8.1 Partial Extraction Methods
Partial extraction techniques have been employed -82-
for many years by exploration geochemists and have
particular usefulness in distinguishing hydromorphic
stream sediment anomalies (i.e. those due to the
action of contaminated water upon sediments) from
- mechanically derived anomalies (i.e. due to the
movement and accumulation of discrete grains weath-
ering from an ore body, (Levinson 1974). Further,
to improve the contrast between background and
anomalous areas, the fraction of the metals asso-
ciated with the stable rock forming silicate miner-
als, common to both areas, may be excluded by partial
chemical analysis. This is also of importance to
the environmental geochemist who will want to dis-
tinguish between metals held weakly within sediments,
which include those derived from pollution sources,
and those held in the rock matrix.
Agemian and Chau (1976) have presented a useful
comparison between a number of extraction techniques
for the determination of metals in sediments. They
propose the simple subdivision into residual and
non-residual metal phases. The former consist of
metals contained within inert silicate minerals and
the latter include exchangeable metals, carbonate,
organic and sulphide phases as well as iron and
manganese oxides. The efficiences of cold 0.5M
hydrochloric acid, 0.05M EDTA, 1M hydroxylammonium
hydrochloride and 25% acetic acid in extracting
heavy metals from a number of sediments were com- -83- pared. It was concluded that 0.5M HC1 gave the best measure of the non-residual metal fraction. Malo
(1977) in a similar but independent study, also concluded that cold HC1 of similar strength should be used to liberate the metals associated with the surface coatings of sediments. Both studies showed that primary silicate minerals were attacked only slightly by the weak acid leaches.
Partial extraction techniques can be used to leach, selectively, metals associated with specific phases within a sediment. An example is the use of hydroxylamine hydrochloride, usually at pH 1-4 to remove manganese oxides and metals associated with them. Rose (1975) has reviewed this aspect of partial extraction techniques, and some examples of procedures available are given below.
Removal of manganese oxides - hydroxylamine hydrochloride at pH 2 (Chao 1972).
Removal of ferromanganese minerals, carbonates and adsorbed trace elements - 25% hydroxylamine hydrochloride and 25% acetic acid (Chester and Hughes
1967).
Ferro-manganese oxides - 2% w/v hydroxylamine hydrochloride + 0.3M ammonium citrate at pH 7
(Whitney 1975).
Organic matter - sodium hypochlorite (Gibbs
1973). -84-
Sulphides - hydrogen peroxide + ascorbic acid
(Lynch 1971).
A number of trace metal partitioning schemes also exist for the successive selective dissolution of different sediment phases (Nissenbaum 1972,
Nissenbaum 1974, Gupta and Chen 1975).
Although techniques of this sort are useful
% in indicating the probable sites of heavy metals in sediments many factors are involved in determ- ining what proportion of the metal content will be released by a particular extractant. These include the nature and strength of the extractant, the leach- ing time and the temperature of the reaction (Levinson
1974). The diagrams in figure 2.2 illustrate the effects of a number of these variables.
Selective chemical extractions are not always exclusive in their action and may affect phases other than those of interest. Subramanian (1975) has shown, using Mtfssbauer spectrometry, that a number of extraction techniques e.g. sodium citrate, peroxide and sodium dithionite can attack clay lattices, for example.
Guy et al (1978) investigated the effects of dilute nitric acid (total specifically adsorbed metal), 1M ammonium chloride (ion-exchangeable) and hydrogen peroxide (organic) on a model sediment artificially comprising hydrous manganese oxide, -85- Fiqure 2.2
Effects of Reaction Temperature and Time on the Extraction of Cu from Sediments.
400
ppm .Cu 200
SO 100 Temp (C)
200 ppm Cu
100
5 "10 15 Time (hours)
A s 30% HN03 for 1 hour
B s Cold 30% HN03 ftc^iAtt <7W U-tvri -86-
solid humic acid and bentonite clay. Their results
indicated that dilute nitric acid did not remove
all the Pb from the oxide phase. Also>interference
between phases prevented 100% extraction efficiency
by peroxide and ammonium chloride. —
It is clear that the results of selective
chemical leaches should be interpreted with caution,
as these procedures do not determine unequivocally
the sites of metals in sediments.
2.8.2 Total Attacks
To achieve a total destruction of sediments
is difficult. Hydrofluoric acid is usually chosen
for this purpose commonly in conjunction with other
acids such as perchloric and nitric. Agemian and
Chau (1976) used a PTFE bomb with a mixture of these
three acids; however the process is lengthy and
the bomb is expensive. Langmyhr and Sveen (1965)
used PTFE beakers with the same reagents, boiling
to dryness twice before taking up the residue in
1M hydrochloric acid. Even with this acid mixture,
minerals such as sphene, magnetite, zircon, chromite,
and ilmenite may not be completely decomposed.
(Levinson 1974). An additional drawback with the
use of PTFE beakers is that elements such as cadmium
can be lost through selective volatilisation (Chapman
et al 1949). -87-
2.8.3 Intermediate Acid Attacks
Three acid combinations are commonly used in
these digestionsjnamely boiling nitric, aqua regia
(1i3 mixture of nitric and hydrochloric) and a
perchloric-nitric acid mixture.
Agemian and Chau (1976) found that the latter
gave the closest approximation to the hydrofluoric
acid total attack, and the method is generally
accepted as yielding an extraction of 95% of the
metals present in sulfides and weathered products,
with a variable and unpredictable degree of attack
upon the primary silicates (Levinson 1974). Aqua
regia will digest all the sulphides, and about 90%
extraction is usually obtained. Boiling nitric
acid was found by Agemian and Chau to yield 76%
of Fe, 75% of Mn, 10% of Cd, 88% of Cu, 70% of Pb,
and 75% of Zn.
2.9 Particle Size Fractionation of Stream Sediments
Stream sediments are usually dried and sieved
in order to obtain a fairly homogeneous and rep-
resentative sample of the original sediment. Oliver
(1973) has shown that the extraction of heavy metals
from sediments is strongly influenced by the grain
size. He found that the highest metal concentration
was associated with the finest grain size sediment.
This is related to the higher surface area and -88- consequent greater adsorption capacity of the fine grained material (see Fig 2.3). Statistically significant correlations were found by Oliver between metal concentration and surface area, con- firming this hypothesis.
Whitney (1975) also found that the maximum concentration of trace metals-occurred in the finest
(silt and clay) fraction of stream sediments. He detected a secondary maximum in the coarser fractions
(coarse sand) and a minimum in the fine and medium sand fractions. The secondary maximum was related to Fe and Mn oxide deposition.
Hawkes and Webb (1965) suggest that the -80 mesh (less than 200 pm) fraction of a sediment provides an homogeneous sample and the greatest contrast between background and anomalous samples.
Sieving is the most convenient way of separating size fractions and is also rapid and sufficiently accurate for most purposes (Allen 1975). To avoid contamination, nylon sieve cloths mounted in plastic frames should be used.
Perhac and Whelan (197 2) showed that the<5 jam fraction (i.e. clay size fraction) was considerably enriched with trace metals compared with the bulk sediment. This fraction consisted predominantly of clay minerals and this coupled with a large surface area contributed jointly to the greater -89- Fiqure 2.3
The Relationship between Surface Area and Trace Metal Adsorption in Sediments.
increasing surface area
or.vj^ (yw) -90-
adsorption capacity of this fraction for trace
metals. Similar results were reported by Glenn
and Van Atta (1973), who found that organic material
(measured by C and N concentrations), cation exchange
capacity and metal concentration increased with
decreasing particle size and increasing clay
mineral content. Their results indicate the im-
portance of organic matter and clay minerals in
removing trace elements from the water column by
sorption processes.
2.10 Water-Sediment Interactions
When solutions of trace heavy metals come
into contact with solid phases, the concentration
of the metal usually decreases through its asso-
ciation with the solid phase. A number of processes
have been suggested to account for the uptake of
aqueous metal ions from solution e.g. adsorption,
chelation, ion exchange and co-precipitation.
These processes may be responsible for reducing
the concentrations of dissolved metals in natural
waters below the concentration prescribed by equi-
librium solubility models. The association of
metals with particulate matter may also affect
the distribution pattern of metals in the aqueous
environment.
2.10.1 Oxidation and Reduction Reactions
The redox potential (Eh) of a system is a -91- measure of the oxidising or reducing potential of
the system. Natural waters are generally highly
dynamic with respect to redox reactions, often far
from an equilibrium state. Changes in the redox
environment can affect trace metals in aquatic —
systems in two ways, 1) by direct changes in the
oxidation state of the metal ion and/or 2) by redox
changes in available and competing ligands or chel-
ates (Leckie and James 1974). Eh-pH diagrams can
be used to predict the stability fields of various metal species, and have been used in the theoretical
chemical modelling of metal speciation for example
by Hem (1972a), Garrels and Christ (1965), and
Hansuld (1966). Although calculations of this
sort are useful in aiding understanding of the
behaviour of metals in water, the complexity of
natural aquatic systems is a clear limitation to
their use. Additionally direct meaningful redox measurements are generally not possible in natural
watexs (Leckie and James 1974, Morris and Stumm
1967). Thus most estimates of the redox environ- ment are indirect or semiquantitative. The beha-
viour of Fe, however, is very accurately described
by Eh-pH conditions.
Lu and Chen (1977) studied the release of
metals from sediments under various oxidising and
reducing conditions. They used sediments of vary-
ing grain size compositions, contaminated by heavy -92-
metals from polluted sources. Mn and Fe were re-
leased to the water column under reducing conditions.
Similarly, Pb and Cd were mobilised under reducing
conditions, but only slightly mobilised under oxi-
dising conditions. Zn, Ni and Cu were effectively
released from the sediment under oxidising condi-
tions, but removed from the water column under
reducing conditions. Cr was not released under
any conditions, due to the slowness of oxidation
from Cr III to Cr IV. Lu and Chen (1977) were
able to conclude that the sediment type does not
control the transport of the metals, the principal
factor being the redox conditions. Metal release
was primarily due to the formation of chloride,
hydroxide, carbonate and organic complexes. The
concentration of metals in the sediment was not
found to affect the amount released to the water
column.
2.10.2 Interactions With Clays
Clays are essentially aluminium and magnesium
silicates with layer like structures. They have
a large surface area per unit weight, and a net
negative charge which enhances the adsorption of
metal ions (Levinson 1974). Mechanisms believed
to be responsible for this charge phenomenon are
i) isomorphous substitution - e.g. Al III for
Si IV in tetrahedral layers (Guy et al 1975). -93-
ii) broken bonds and iii) lattice defects. The
negative charge can be balanced by counter-ions 2 + + + such as Ca , Na and K held between the layers,
usually with envelopes of water morecules. The
exchange capacity of a clay is, therefore, essen-
tially fixed by the nature of the basic clay lat-
tice. It will be relatively insensitive to changes
in the surrounding solution up to the point at
which the clay mineral is no longer stable. (Rose
1975).
Reactions for trace metals in the exchange
sites of clays are of the type:
ox 2 + Ca-clay +Zn * Zn-clay + Ca
Ca-clay represents the clay with Ca 2 + i. n the exchange site, Zn-clay the clay with Zn 2+ i. n the 2+ 2 + exchange site. Zn and Ca are the aqueous species. Clearly if both solution species are • present, the clay will have a mixed population of ions in the exchange sites. The Zn content of the 2 + clay will be dependent on the Ca in solution as well as the Zn 2 + concentration (Rose 1975).
In general, ions of higher effective charge are preferred in the exchange sites. Some univa- lent ions, however, (K & form strong bonds in the interlayer space, and can cause collapse of this space. In this manner, trace metals can -94-
be occluded in the lattice structure and be unav-
ailable for further exchange reactions. The
release of trace elements occluded in the clay
lattice will be a function of the stability of the
-mineral, and the prevailing conditions in the sur-
rounding solution. The dissolution of clays will
be controlled largely by the solubility of alum-
inium (Rose 1975). Within the pH range 5-8,
aluminium solubility is low (Parks 1972). At pH
values less than 3, clays dissolve significantly
and trace elements will be released.
Ion exchange reaction rates are rapid in dis-
persed clays, where solutions have ready access
to exchange sites. If the clays are agglomerated
as in many natural situations, reaction rates are
reduced.
2.10.3 Interactions with Iron and Manganese Oxides
There are many accounts of the scavenging
properties of hydrous Fe and Mn oxides for trace
heavy metals in river waters in the literature.
Jenne (1968), reviewing the available information
on Co, Ni, Cu, Zn, in soils, fresh water sediments
and fresh water, has concluded that hydrous oxides
of Fe and Mn exert major controls on the availa-
bility of these metals in the environment. Adsor-
ption, (or desorption) of heavy metals will occur
in response to the following: -95-
i) aqueous content of the metal in question
ii) aqueous content of the competing metals
iii) pH and Eh of the system
iv) concentration of other ions capable of
forming inorganic complexes
v)« the type and concentration of organic
chelates
The ubiquitous nature of the oxides of Fe and
Mn in soils, clays and sediments as partial coatings on silicates rather than as discrete well crystallised minerals allows them to exert a chemical activity far out of proportion to their actual concentration
(Jenne 1968). Mn oxides, for example, may have surface areas of as much as a few hundred metres per gramme and a larger cation exchange capacity than some clay minerals (Morgan and Stumm 1964).
The processes of scavenging of heavy metals are complex and ill understood (Levinson 1974).
Five mechanisms have been detailed by Chao and
Theobald (1976)i i) co-precipitation, ii) adsorp-
tion, iii) surface complex formation, iv) ion exchange, v) penetration of the crystal lattice. Redox processes involving trace metals at the oxide surfaces are also thought to be important (Hem
1977 and 1978).
Clearly these mechanisms will not act in
isolation, but interactions involving some or all -96-
the processes may take place. The pH sensitivity
and the reversibility of adsorption reactions are
important features of adsorption processes at oxide
surfaces. The age of the oxide precipitates and
the role of organic matter are also important.
Freshly precipitated oxides have markedly different
sorption characteristics from aged oxides. As the
oxides age, molecular rearrangements can occur, which improve the crystallinity of the material.
Other materials may also be sorbed by the oxides
and both processes will tend to reduce the sorption
capacity of the aging oxide precipitates (Lee 1975).
Organic material can have a three-fold role. It may produce a periodic reducing environment, main-
taining Mn and Fe oxides in a hydrous micro-
crystalline condition (Jenne 1968); it may solu-
bilise the oxides under prolonged reducing condi-
tions and it may chelate metal ions, thereby increa-
sing their mobility and dispersion (Chao and Theobald
1976).
Carpenter et al (1978) and Carpenter and Hayes
(1978) have proposed a geochemical model, consistent
with observed field relationshipsjfor Fe and Mn
oxide formation in stream sediments. Coatings are
usually best developed on boulders and large pebbles
and outcrops in moderate to swift flowing shallow
streams. They are generally absent in swampy areas.
Coatings rarely extend below the sediment water -97-
interface and transported boulders, partially cover-
ed in sediment, typically show bleached surfaces
below the sediment water interface. The oxide
surfaces are often extremely biologically active
and a number of photosynthetic organisms have been
found on them (Carpenter and Hayes 1978) . The 2 + proposed model involves the introduction of Fe 2+ and Mn and other metal ions into the stream from
groundwater percolating upwards into the stream
beds. As the reduced groundwater meets oxygenated
surface water, nucleation and precipitation of
Fe-Mn oxides can occur. Other trace metals may be
incorporated by co-precipitation or various sorption
mechani sms. They suggest that micro—organisms may
play an active part in oxide precipitation processes.
Bacteria can provide some chemical conditioning
of fresh rock surfaces and may metabolise and re-
deposit some of the metals. Photosynthesizers
(e.g. diatoms, phytoflagellates, and filamentous
algae) release large quantities of oxygen near the
rock-water interface where Fe-Mn oxides are pre-
cipitating (Carpenter et al 1978).
2.10.4 Interactions with Organic Matter
The role of soluble organic materials in forming
stable metal-organic complexes in solution has already
been discussed (see Section 2.6.5). Organic matter
is also an important factor in the adsorption and -98- binding of certain heavy metals in stream sediments, although there are diverse opinions as to its imp- ortance in comparison with hydrous Fe-Mn oxides
(Levinson 1974). Rashid (1974) has demonstrated that sedimentary humic materials are capable of removing metals from the water column. The proces- ses involved were thought to be ion-exchange, che- lation and surface adsorption. Under experimental conditions, Cu was found to be preferentially bound)
ral^ev tw* Zn, Ni, Co, and Mn. Cu also exhibited the highest binding strength in comparison with the other metals. Gardiner (1974b) argues that humic materials in river muds are the major component responsible for the adsorption of Cd. He also noted that rates of adsorption and desorption were rapid. Ramamoorthy and Rust (1978) found a direct correlation between the binding capacity of river sediments for metals and organic matter content.
Guy et al (1975), have suggested mechanisms for the sorption of metals to sedimentary humic materials in particulate matter. They conclude that the amount of metal sorbed is proportional to the number of available complexing sites, lead- ing to a limiting sorption value. The relative affinity of different metals for humic materials will be a function of the availability of the ions to form metal chelates. The pH of the solution is also an important control", as the conditional sta- -99- bility constants of the metal complex decrease in magnitude with pH (due to competition by H+ for sites) . At low pH, the complex is destabilised and the metal desorbed into~solution.
In the natural environment the interpretation of metal-organic binding phenomena in sediments (as in solution) must take into account the competition by major cations and Fe for binding sites. There is again no reason to suppose, at present, that the sites available in humic materials for metal com- plexation show any preference towards heavy metals.
Cu failed to show preferential adsorption to humic material, when adsorption experiments were conducted using sea-water (Rashid 1974). Large quantities of alkaline and alkaline earth metals were adsorbed onto the peat, and Rashid (1974) concluded that the presence of large quantities of K, Na, Ca, and Mg in sea-water and the undersaturation of the tran- sition metals would limit the adsorption of the latter.
The role of organic material in association with hydrous Fe-Mn oxides has already been mentioned.
Jenne (1968) argues that the general role of organic material in soils and sediments is to produce a periodic reducing environment necessary to maintain
Fe-Mn oxides in a hydrous micro-crystalline condi- tion. It is thought that this indirect process is -100- usually the major role of organic matter in soils and sediments, the principal direct control on heavy metal availability being exerted by hydrous Fe-Mn oxides (Jenne 1968). Organic matter will, however, play a direct role in the following* i) during periods of low Eh (and pH) where organic complexes will serve to reduce the amount of metal removed by water passing through the sediment, and ii) in highly organic sediments when the sheer quantity of organic matter will dominate the availability of the heavy metals (Jenre 1968) .
Humic substances are also known to have an affinity for clay minerals, ferric hydroxide, and calcium carbonate (Thorne 1978). The relationships between clays and organic substances have been re- viewed by Mortland (1970) and Greenland (1971).
The main reaction mechanisms between clays and humic materials are i) anionic exchange reactions or non- specific adsorption, ii) ligand exchange reactions or specific adsorption, and iii) hydrogen bonding.
Clays may protect humic materials from bio-degra- dation and conversely the clay sorption capacity can be reduced. Clays may be kept in suspension due to a surface covering of humic material which can prevent flocculation in estuarine environments.
Linking of organic matter to clay particles via polyvalent cations can also occur (Edwards and
Bremmer 1967). In this situation, microaggregates -101-
of very small particle size may be formed. The
removal of metal ions from solution will occur by
a mixture of mechanisms, for example adsorption onto
clay and precipitation by the organic material.
2.10.5 Re-mobilisation of Heavy Metals from Sediments
The re-mobilisation of heavy metals from sediments
in response to changes in Eh and pH have already been
mentioned (Section 2.10.1). In addition to stabi-
lising heavy metals in solution (Theis and Singer
1973), soluble organic material of humic acid type
have been found to re-mobilise metals from sediments
(Jackson and Skippen 1978). The results of labora-
tory model experiments indicated that Cu, Ni, Zn
and Pb were stabilised in solution in the presence
of sorbing media such as clays and Mn02» Hydrolysis
and adsorption to clays tended to destabilise the Zn
and Ni organic complexes, and the Pb-complex tended
to coagulate to form colloids. All four metals
were remobilised from the sediment phase by humic
and fulvic acids in solution. The presence of
bicarbonate/carbonate in the water was found to
decrease Ni and Zn solubilities possibly due to
interference by carbonate reactions. Experimentally,
shaking sediments with solutions containing NTA has
been shown to release heavy metals from sediments
(Banat et al 1974).
In experiments using lake sediments and NTA, -102-
EDTA, and TPP (Tripolypnospnate), levels of Fe, Mn,
Pb, and Zn were found to be elevated in standing
water to which the organic compounds had been added.
For a flowing system, however, only the concentration
of Zn in the water was significantly raised (Barica
et al 1973). However, NTA-metal chelates are bio-
degradable in river water at environmentally real-
istic concentrations (Swisher et al 1973). There
seems little reason to suppose that NTA-metal
chelates would accumulate in the environment, even
with the extensive use of NTA in detergent formu-
lations. The presence of NTA, EDTA and TPP in
detergents present at high concentrations in waste
water discharges, could cause mobilisation of heavy
metals from sediments. Although the metal chelates
themselves might be degradable with time, this could
still cause enhanced dispersion of metals in a river
system.
2.11 Water-Suspended Sediment Interactions
The sorption of heavy metals by suspended
solids has been shown to be a function of the nature
of the material, its size, and the metal being ad-
sorbed (Kharkar et al 1968). Particulate organics,
such as humic and fulvic substances and hydrous
oxides of Fe and Mn have the ability to bind metals
in the particulate phase (Williams et al 1973). In
addition, the physical and chemical conditions of -103- the system can affect the distribution of the metals between suspended load and solution (Leckie and
James 1974). In common with sediments, the amount of metal adsorbed increases with decreasing particle size and increasing surface area (Andelman 1973).
Processes involved for heavy metals in particulate/ water interactions are essentially analagous to
those found in the deposited sediments.
Guy et al (1975), arranged a simple chemical model to investigate the mechanisms controlling
the partitioning of metals between soluble and
particulate phases. They found that at pH 5.0 and
above, 50% of Cu in the water was sorbed on par-
ticulate matter. The soluble Cu was in the form
of an organo-metallic complex. Between pH 6.0
and pH 3.8, the soluble Cu was equally distributed
between organic complexes and "free" hydrated ions.
Between pH 4.2 and pH 2.5 Cu was progressively
desorbed from the particulate, with all the Cu
existing as "free" ionic species below pH 2.5.
Gardiner (1974b) found that Cd was only predomi-
nantly associated with suspended particulates at
relatively high suspended solids concentrations.
Gibbs (1973 & 1977) has investigated the
partitioning of trace metals among mineral organic
and Fe-oxide phases of suspended particulate, in
the Amazon and Yukon river systems. Ni and Mn -104- were mainly associated with metallic coatings in
with transport in crystalline particles of secondary importance. For Fe, the two phases were of approximately equal importance.
Co and Cu were mainly carried in crystalline par- ticles.
Desorption of metals from particulates is also possible where dramatic changes in water composition are encountered. This is particularly significant in estuaries, or where acidic mine drainage enters a river (Thorne 1978). The amount of suspended matter carried by a river is affected by the flow (Angino et al 1974), and fine grained bottom sediment may be re-entrained during periods of storm flow (Williams et al 1973). An appreci- ation of the flow characteristics of a river is therefore important in interpreting heavy metal/ particulate concentrations. -105-
CHAPTER 3
DESCRIPTION OF FIELD AREAS
3.1 The Minsterley Brook - Rea Brook Catchment
3.1.1 General Description
Minsterley Brook, known also as Hope Brook
in its upper reaches, rises as a small seepage in
marshy ground in an upland area to the north west
of Shelve in Shropshire, (Figure 3.1). It flows
north-eastwards from this point for a distance of
approximately % km before running underground in
an area of marshy land adjacent to the spoil heaps
at Gravels. The stream reappears from a portal
beneath the main dump about 200 m further north
east. It continues to flow as a small stream through
a steep sided valley for 6 km before reaching the
edge of the Rea Brook floodplain. At Malehurst,
approximately 10.5 km from its source, Minsterley
Brook joins the larger Rea Brook which fl'ows north
eastwards for 19 km through a broad floodplain to
join the River Severn at Shrewsbury. The catch-
ment of Minsterley Brook has an area of approxi-
mately 21 km 2 . The total area of the Rea Brook 2 catchment, including Minsterley Brook, is 178 km
(Severn Trent Water Authority 1978).
The topography of the upper reaches of iH-
a> u)
fc> H- pj ot) fD ^ IH pa
o |H> 0 H- cr1> |W (D I H h ltd o oJ* -107-
Key to Figure 3.1
($> Stream sample site
• Lead Mine
& Drainage adit
• Mineral processing works
^ Abstraction point
fJ Effluent input
M Permanent river guaging station
K\M Built-up area
See text for details of letter and number codes.
SoOvLO ^nVa •. ;
ms ferocW AllfeuV (m?)
(KVNJl foinVs Tr««lr uiak* Cm*) -108-
Minsterley Brook consists of steep sided, rounded hills reaching a maximum height of 502 m. above sea level along the Stiperstones to the east and
400 m above sea level in the west. The vegetation is principally rough grassland and heath with
Forestry Commission conifer plantations. North- eastwards the land becomes fla.tter and is domina- ted by the floodplain of Rea Brook and, further to the north east, that of the River Severn. The floodplain mainly supports arable farming and gra- zing pasture.
In the village of Minsterley there is some light industry, the largest concern being that of the Express Dairy. This company extracts water from the brook at the site marked A3 shown in
Figure 3.1 and discharges an effluent of cooling water and site drainage into the Brook at SJ 377054
Site El, Figure 3.1. The effluent input has an average flow of 0.14 Ml/day (Severn Trent Water
Authority 1978) and chemical data for the effluent are shown in Table 3.1.
Water reclamation works at SJ 373058 (site
E3, Figure 3.1) near Minsterley and at SJ 400065
(site E2, Figure 3.1) near Pontesbury also disch- arge effluent into the Brook. Their average daily flows are 0.36 Ml/day and 0.27 Ml/day respectively.
Results of chemical analyses of the effluent are -109-
snown in Table 3.1.
Water is abstracted from Minsterley Brook (at
sites A4 and A5, Figure 3.1) by Th. S. Van der Lann
(U.K.) Ltd. for the industrial unit at Minsterley,
the water being used for cooling. Boycott Farm
(SJ 387074) also abstracts water from Rea Brook at
two points (SJ 389078, SJ 385070; site Al and site
A2, Figure 3.1) for spray irrigation.
The flow of Rea Brook is measured at a perma-
nent gauging station by the Severn Trent Water
Authority at Hook-a-Gate (SJ 466092). Sample site
134 is located adjacent to this point. The mean
daily flow for the period October 1977 to September
1978 was 130.68 Ml/day. The highest mean daily
flow was 896.6 Ml/day in February 1978 and the
lowest was 20.1 Ml/day in September 1978.
3.1.2 Solid Geology of the Minsterley - Rea Brook Catchment
The geology of the upper part of this catchment
consists of the Ordovician rocks of the Shelve inlier
west of the Stiperstones quartzite, see Figure 3.2.
Over 3,700 m of Ordovician strata exist in this area
and full accounts of the sedimentary rocks are given
by Watts (1925), Whittard (1931) and (1952) and of
the volcanic and igneous rocks by Blyth (1938) and
(1944) and Watts (1925). Only the lithologies re-
levant to this research have been listed and des- -110-
Table 3.1
Effluent Analyses - Minsterley Brook
BOD SS (-NH-JN pH n
Minsterley WRW 12 17 1.9 —
Pontesbury WRW 32 30 9.5 -
Express Dairy 12 16 2.7 7.9
BOD Biochemical oxygen demand (mg/l)
SS Suspended solids (mg/l)
(NH^)N Nitrogen as ammonia (mg/l)
n No. of determinations
WRW Water Reclamation Works
- No data available
All results, mean values. For years 1976 - 1977 -111- cribed.
i) Stiperstones Quartzite - Resting unconformably
on Cambrian shales, a hard white or grey sili-
ceous sandstone with beds of conglomerate and
occasional thin shale beds.
ii) Mytton and Tankerville Beds - Bluish grey
shales and brown weathering micaceous silt-
stones . iii) Hope Shales - A thick sequence (240 m +) of
soft black shales with beds of very fine
grained tuff in the middle and upper parts.
iv) Stapeley Volcanic Group - Waterlain andesites
tuffs and breccias with some lavas and inter-
bedded shales.
v) Hagley Volcanic Group - Massive crystal and
lithic tuffs, often brecciated with occasional
lavas.
vi) Igneous Intrusions - Dolerite sills and dykes
with affinities to alkaline plateau basalt or
olivine basalt magma type.
The general dip of the strata is westwards, though there are two folds, a syncline with an axis trending north northeast about 2.5 km west of the
Stiperstones ridge and a complementary anticline, -112-
Fiqure 3.2 Simplified Geology of the Minsterley Brook
Catchment Key to Figure 3.2. -113-
Alluvium River Terraces Recent Deposits Fluvio-Glacial Flood Gravels
Lower Mottled Sandstone Triassic
Keele Beds • Carboniferous
Coed yr Allt Group ( U%Coal Measures)
vVenlock Shales Silurian
Upper Weston Grits Weston Shales Lower Weston Grits Stapeley Shales Stapeley Volcanic Group Ordovician Hope Shales Mytton and Tankerville Flags Stiperstones Quartzite
Shineton Shales Cambrian
Longmyndian Pre-Cambrian Uriconian
Dolerite Intrusions
tk «A [VKZ) -114- of similar trend, about 1.6 km further west and running through the village of Shelve. This anti- cline is important as it brings the ore bearing Mytton Beds to the surface as an inlier surround- ing Shelve. The major faults in the Ordovician rocks trend northwest and north northeast, with mi- nor faults trending east northeast.
The intrusive rocks in the area can be divi- ded into two groups on the basis of age. The earlier occupy the north northeasterly trending fault fissures and are probably early Silurian in age being associated with folding (Dines 1958). The later dykes occupy fissures with northwest and east northeast trends, that is fissures with the same trend as those bearing mineral veins. Where the two intersect, the dyke rock is sericitized (Hall 1922, Morton 1869). This proves that the igneous rocks are older and implies that there is no close genetic connection between them and the mineral veins.
The more important mineral veins also have two trends, either north west or east northeast. The latter trend contains the principal ore bodies which often occur at fault intersections. The miner- alisation, however, appears to post-date the faulting as a few ore bodies are themselves faulted. Where later movement has occurred, the vein breccias are -115- in no cases known to be cemented (Dines 1958). Subsidiary ore bodies also occur between bedding planes where bedding-plane slip has allowed the mineralising fluids to enter (Hall 1922). The prin- cipal minerals found in the main lodes are galena and sphalerite with strings of chalcopyrite. Barite, calcite and quartz constitute -the gangue minerals. At East Roman Gravels the mineral veins occur close to Minsterley Brook, however there is no field evi- dence of outcrop in the stream bed.
The country rock controls the distribution of the faulting and the mineralisation to a considerable extent. Faults are developed best in the competent rocks of the Mytton Beds and Stapely Volcanics, where they may extend for considerable distances. In the less competent shaley horizons the faults tend to die out, or where they do occur to form shatter zones. The Hope Shales do not contain any workable ore deposits and have tended to act as a cap rock to the passage of mineralising fluids from the underlying Mytton Beds. Consequently there is no mineralisation in the bed of Minsterley Brook or the land immediately north west of the brook at East Roman Gravels. A trial shaft sunk in this area proved only barren shales. The Mytton Beds have therefore been exploited by mining, though at the top of the sequence where intercalations of -116-
shale occur, these too have proved barren. There are mineral veins in higher stratigraphic horizons, for example in the Stapley Volcanics and the Hagley Volcanics where escape of mineral bearing fluids through the shales has occurred. Such veins contain barite with only traces of galena and sphalerite.
Morton (1869), Dines (1958) and Hall (1922) all suggest a zonation of the mineralisation with depth. The sequence proposed, from shallowest to deepest, being barite, lead, zinc. The copper zone, usually accepted as being below the zinc, is absent.
To the north of the village of Hope, the Ordovician shales are overlain unconformably by the Silurian Kenley Grits, a coarse yellow-brown sand- stone with locally developed conglomerate and pebble beds (Pocock et al 1938). These in turn are overlain unconformably by the Coed-yr-Allt and Keele Beds of the Upper Coal Measures. The former consist of alternating beds of sandstones, shales and marls with a persistent limestone band and three workable coal seams. The Keele Beds consist of marls and sandstones with calcareous lenses (Earp and Hains 1971). These two constitute the Hanwood Coalfield.
3.1.3 Pleistocene and Recent Deposits in the Minsterley - Rea Brook Catchment
Much of the younger strata to the north of the -117-
Ordovician are covered by boulder clay. In the valley of Rea Brook, deposits of fluvio-glacial flood-gravels occur. These are predominantly coarse gravels containing some angular blocks of up to 300 cm in size and lenticles of coarse sand with a clay matrix. Three river terraces have been recognised (Pocock et al 1938). and these consist of clayey, fairly coarse, river gravels.
In the upper sections of Minsterley Brook little alluvium has accummulated and the stream runs directly over exposed bedrock. Bedrock is also exposed in the valley sides, though where these are less steep alluvial deposits occur which eventually coalesce with those of Rea Brook. Stream sediment in the upper reaches of the brook are com- posed mainly of fine grained mine waste and shale fragments. The former is recognisable as white cleavage fragments of calcite. These particles become less frequent in occurrence and smaller and more rounded. Discrete calcite fragments still occur in the sediment at site 126. Since no other sources of calcite in this form are known in the catchment, they must have their origin at Gravels some 18 km upstream. Below Minsterley, the fine sediment ( <2 mm) becomes scarce and occurs as small accummulations behind the large angular boulders that make up the stream bed. These boulders are set in a hard substrate of yellow clay. Banks of -118-
gravels and fine materials also occur on the in- sides of some of the meander bends. Iron and manganese oxide staining on boulders and stones is generally scarce.
3.1.4 History of Metalliferous and Coal Mining in West Shropshire •
Lead mining in the Shelve district is known to date back to Roman times, when veins outcrop- ping on the hill slopes at mines now known as Roman Gravels and East Roman Gravels as well as other localities, were worked (Figure 3.1, Table 3.2). The Roman excavations at Roman Gravels are reputed to be over 30 m in depth (Morton 1869), which, due to the topography and with aid from short drainage adits, would de-water easily. Roman re- mains have been found in the old workings, notably lead pigs bearing the stamp of the Emperor Hadrian (AD 117 - 138).
The area was actively worked in the 12th and 13th centuries at Hope and East Grit Mine, and during the early 19th century Batholes, Roman Gravels, East Roman Gravels, East Grit, White Grit, Pennerley and Bog Mines were active. Few records exist, however, of the mines or the deposits ex- ploited apart from the accounts by Murchison (1839) and Morton (1869). Published records of lead pro- -119-
Table 3.2
Names and Locations of Drainaqe Adit Portals and some Mines in the Minsterley Brook Catchment
Drainaqe Adits Ref.to Name NGR Fig.3.1 i Brick Kiln Level Not known - Wood Level SJ 336007 A Boat Level SO 358999 B Snailbeach Level SJ 364025 C Gate Level SJ 336007 D Leigh Level SJ 330036 E
Closure Mines NGR Ore Type date Ref. (Approx) Fiq. Knick Knolls SJ 342005 Ba 1876 1 Batholes SJ 335003 Pb 1877 2 East Roman Gravels SJ 334002 Pb Zn Ca 1901 3 Roman Gravels SO 333999 Pb Zn Ba 1912 4 Sth. Roman Gravels SO 342996 Pb Ba 1882 5 Ladywell SO 327994 Pb 1880 6
The Grits SO 320980 Pb Zn 1901 — Snailbeach SJ 375022 Pb Zn Ba 1920 8 New Central SJ 369016 Pb 1872 9 Myttons Beach SJ 369005 Pb c 1800 10 Perkins Beach SJ 365998 Pb Ba 19 24 11 Burgam so 358996 Pb Zn Ba 1961 12 Roundhill so 351996 Pb Ba 1913 13 Tankerville so 355995 Pb Ba 1894 14 Potters Pit so 357993 Pb 1868 15 Pennerley so 353988 Pb Zn Ba 1895 16 Ritton Castle so 345977 Pb c 1800 - Bog so 357978 Pb Zn 1915 18
[ -120-
Table 3.2 contd.
Closure Mines NGR Ore Type date Ref. to (Approx) Fiq . 3.1 Wrentnall* SJ 417032 Ba 1925 19 Huglith SJ 405015 Ba 1945 20 Westcott SJ 405013 Cu . 7 21 Cothercott SJ 407002 Ba 1928 22 Hanwood Colliery SJ 436093 1941 23
Locations of Ore Processing Sites in the Minsterley Brook Catchment
Ore Ref.to Treated NGR Fig.3.1 Pontesford Pb SJ M 3 Malehurst Pb Ba SJ M 2 Cliffdale Ba SJ M 1 Hanwood Ba SJ M 4
NGR = National Grid Reference
Source of Data s Adams (1967) : Brook and Allbutt (1973) : Brown (1976) s Dines (1958) -121- duction commenced in 1845, though for a number of mines their most productive period was probably prior to this date. There seemed to have been little demand for zinc before 1858 and barytes before 1860. The peak period of production for the whole area was between 1870 and 1885 but by the beginning of the 20th century production had declined. Only three mines, Snailbeach, East Roman Gravels and Perkinsbeach, were yielding significant amounts of lead by 1913. All lead production in the area had ceased by 1915.
The production of zinc, about a tenth of lead, followed much the same trend, with a few mines con- tinuing in the 20th century to raise zinc after the lead ore bodies had been exhausted. Barytes, with calcite as a by-product, was the last mineral seriously mined in the area, and production con- tinued into the 1940,s.
The total output of lead ore for the area between 1845 and 1913 amounted to 235,630 tons, with a peak of 8,000 tons per year in the late 18701s. Output of zinc between 1858 and 1913 to- talled 18,994 tons, with 914 tons as the highest yearly figure in 1882. The recorded output of barytes between 1860 and 1913 amounted to 271,397 tons with a maximum of 13,772 tons in 1913. From this period production from all mines declined -122- with the exception of Huglitn mine, which raised 295,108 tons between 1914 and 1944.
To the north of the lead mining area and asso- ciated with Carboniferous strata is the small Hanwood Coalfield. This provided fuel for the steam pumping and winding engines at the lead mines and the smelt mills in the area. Often collieries and mills were owned and operated by the lead min- ing companies, as was the case, for example, of the pits and mill at Pontesford owned by the oper- ators of Snailbeach mine (Brook and Allbutt 1973).
Mining in the Hanwood Coalfield extends back at least to the beginning of the 19th century, as it was observed in 1839 by Murchison that mining operations had been continuing for at least 20 years. Three seams were worked, the Thin or Deep Coal (0.38 m - 0.53 m thick), the Yard Coal (0.76 m - 0.91 m thick) and the Half Yard Coal (approx. 0.38 m thick). The Deep Coal was the better quality seam and most extensively worked, the maximum depth of workings being about 150 m (Earp and Haines 1971).
The majority of the mines in the western part of the coalfield appear to have closed by the mid- nineteenth century, whilst those centred around Asterley and Pontesbury continued working until the end of the century (Pocock et al 1938). The last important colliery, situated near Great Hanwood -123-
(at SJ 436093 No.23 Figure 3.1), closed in 1941, whilst a small pit near Pontesbury continued work- ing until 1947 (Earp and Haines 1971).
Smelting before 1700 was carried out in simple furna'ces built on open hillsides using a wood fire with the south westerly winds to create a draught. The history of the smelting industry in the area is poorly documented, although before 1932 works existed at Pontesford (SJ 409061 site M3, Figure 3.1), near Pontesbury (Wadlow 1959). As mentioned above, these works were owned and operated by the Snailbeach Mining Company, but in 1863 the works were abandoned in favour of new ones built at Snailbeach Mine itself. Generally, during the 1860's mines sold their lead ore directly to big smelting companies and no longer operated their own mills (Brook and Allbutt 1973).
Another lead smelting works was situated at Malehurst (SJ 384060 site M2, Figure 3.1) along with a small colliery, but its history is not known. A barytes mill operated on the site from 1922 to 1948, and since 1956 the mill has been used for the preparation of animal foodstuffs (Brown 1976). A barytes mill also worked at Cliffdale (SJ 365025 site Ml, Figure 3.1) powered by water draining from the Snailbeach mines. The history is again unknown. A third mill operated at Hanwood (SJ 441093 site M4, -124-
Figure 3.1) again treating barytes, from 1886 to 1922 (Brown 1976).
3.1.5 Description of Mine Drainaqe
'Figure 3.1 shows the location of the principal mine adits in the area and Table 3.2 gives the grid references of adit entrances and mines mentioned in the text. The adits draining New Central Mine and Batholes Mine (the Brick Kiln Level) were not located during this study or by an earlier detailed survey of the area conducted by Adams (1967). Their location is thus approximate and is taken from Adams (1967).
Wood Level and Boat Level (sites A & B, Figure 3.1) both have significant flows of water. The former drains the mines known as East Grit, Ladywell, Roman Gravels and East Roman Gravels. The latter drains the Burgam, Tankerville, Potters Pit, Pennerley and Bog Mines. Snailbeach Adit (site C, Figure 3.1) which joins Minsterley Brook at the Cliffdale Barytes mill has a small though steady flow. Gate Level (site D, Figure 3.1) is merely a seepage, as the entrance has caved in.
It is thought that Minsterley Brook is receiv- ing mine drainage water in large quantities from a point below the dump at Gravels. As mentioned earlier, the stream disappears underground in an -125-
area of marshy ground, re-appearing at a portal located in Figure 3.3. The volume of water leaving the tunnel appears, by observation, to be far larger than that flowing in the brook at the point of dis- appearance. In addition the sound of falling water can be heard distinctly from the mouth of the tunnel, suggesting that the brook is receiving water from a confined source underground. There is no record in the literature of subsidiary drainage of the Gravels mines into Minsterley Brook other than by the Wood Level. A section of the workings on Roman Vein drawn by the mining engineer Arthur Waters in 1892 for the Roman Gravels Mining Company shows a level which continues beneath the road (now the A488) to a point below the mine waste, where it stops. It is possible that this, or water from collapsed workings, are draining into the brook beneath the mine dump.
3.1.6 Description of the Mine Dumps at Gravels
Large dumps of waste material covering an area 2 of some 1,900 m occur on the eastern bank of Min- sterley Brook in the vicinity of Gravels (Figure 3.3). The material is waste from both mining oper- ations and ore dressing processes, and consist of two distinct types of material. The first, which predominates in quantity, has a particle size range of 500 mm down to less than 61 ^im and is composed -126-
Plan of the Roman Gravels Mine Dump
Area of waste material
Sample site -127- mainiy of caicite with country rock (shale) and ore minerals. This material is the waste product of ore dressing. The remaining material, which was not treated, consists of blocks and boulders of country rock ranging in size from 10 cm to 30 cm, and similar sized blocks of caicite. This material would have been raised during -shaft sinking and opening of unproductive ground near the surface. Boulders of caicite up to 0.5 m across have also been seen on the dump, along with blocks of sphal- erite up to 30 cm across. Along the south-eastern bank of the stream the dump material collapses freely into the stream channel and comprises the stream sediment at this point.
3.2 The River Ecclesbourne Catchment
3.2.1 General Description
The River Ecclesbourne rises as two tributaries immediately to the south of the small market town of Wirksworth in Derbyshire. The western tribut- ary rises as a spring in wooded ground, and the eastern one emerges from underground via a culvert at the eastern edge of the town. The river flows south-eastwards from the junction of the two feeder tributaries for approximately 15 km to meet the River Derwent at Duffield (Figure 3.4). The area of the Ecclesbourne catchment is 50.40 sq km (Severn -128-
Fiaure 3.4 Drainage Plan of the River Ecclesbourne -129-
Key to Figure 3.4
O Stream Sample site w • Works T Drainage sough entrance c ® Cupola smelter site b ® Bole-hill smelter site Permanent river guaging station Built-up area
See text for details of letter and number codes -130-
Trent Water Authority 197?) .
The river valley is broad and flat based. At its northeastern edge the land rises steeply to the plateau formed by the Millstone Grit, at a height of bdtween 250 m and 300 m above sea level. To the vest and southwest the topography is more rounded, reaching between 200 m and 250 m above sea level with gentler slopes. The higher ground on both sides of the valley is dissected by a number of tributaries flowing into the Ecclesbourne.
The area is rural, and the valley floor is dominated by grazing pastureland. There is light industry at Wirksworth, in particular a clothing and dye works (SK 284526 site W4, Figure 3.4) is situated adjacent to the river on the southern out- skirts of the town. No effluent is discharged into the river by the works (Severn Trent Water Authority pers. comm. 1978) .
Two hundred metres further downstream is the Wirksworth Water Reclamation Works (WRW) (SK 284523 site W1, Figure 3.4) which discharges effluent into the river at an average flow of 2.0 Ml/day (Severn Trent Water Authority 1978). Work is currently being undertaken (1977/78) to improve the effluent quality of this works. Two small WRW's located at Idridgehay (SK 289485) and Turnditch (SK 305467) (sites W2 & W3, Figure 3.4) discharge very small -131- voiumes of effluent into the river ( <0.06 Ml/day/ works) (Severn Trent Water Authority 1978). The results of chemical analyses of the effluents per- formed by the Severn Trent Water Authority are shown in Table 3.3. The effluent discharge rates can be compared with the mean river discharge rate for the period October 1977 - September 1978 of 57.6 Ml/day measured at the guaging station near Duffield at SK 320447. The maximum mean daily flow for this period was 1131.32 Ml/day in January 1978 and the minimum daily flow was 11.06 Ml/day in September 1978.
3.2.2 Geology of the Wirksworth Area
The Carboniferous limestone to the north of Wirksworth consists of three groups, which are, from oldest to youngest:
Hoptonwood Group - pale grey, coarse to medium grained limestone with few macrofossils except those in isolated thin bands. In the vicinity of Wirksworth the topmost beds pass into dis- turbed and brecciated strata.
Matlock Group - this is a predominantly grey to dark grey medium grained limestone with fossiliferous bands and local developments of chert. The beds thin southwards and approaching Wirksworth non-sequences and breccias become evident. Both groups are Effluent Analyses - River Ecclesbourne cj Mcr fl> SS Alk. T. Chloride n U) 2H BOD N(NH3I NGR Hardness CI. • U)
Worksworth 7.1 12.8 21 3.0 109 215 93 SK 284523 9
Kirk Ireton - 30 31 9.5 - - - SK 270498 12
Turnditch - 33 39 11.0 - - - SK 305467 12
w rlo Alk. = Alkalinity as CaC03 (mg/l)
T. Hardness = Total hardness as CaC03 (mg/l)
N(NH3) = Nitrogen as ammonia (mg/l) SS = Suspended Solids (mg/l) BOD = Biochemical Oxygen Demand (mg/l) NGR = National Grid Reference n = Number of determinations = No data available
Results are means of the n determinations covering the years 1976 and 1977 ( Seuuvx l/Oah>„ /WW'.U W*) -133-
believed to be cut out by an unconformity below the Cawdor Group, south of Wirksworth.
Cawdor Group - a variable fossiliferous lime- stone commonly thinly bedded dark and cherty •with reef knolls and crinoidal beds at the base.
The Hoptonwood and Matlock Groups are typical massif facies limestones. In the Wirksworth area, where the sequence thins and becomes disturbed, it is thought that the rocks form part of an apron-reef complex largely concealed by the overlying Cawdor Group and Namurian Shales.
The beds of the Hoptonwood and Matlock Groups are extensively secondarily dolomitised, and inter- bedded with them are lavas, tuffs and clay bands (wayboards), alteration products of the igneous rocks. The lavas are olivine basalts, often amygdaloidal and altered at the margins to soft green clay. The lavas in the vicinity of Wirksworth belong to the Matlock Lower Lava Group.
The Cawdor Group limestones are overlain by dark shales with thin limestone bands. These pass, possibly unconformably, into the overlying shales of the Millstone Grit Series.
The lowest Namurian beds are mudstones which gradually become more silty and merge into the inter- -134-
bedded siItstones and sandstones of the Ashover Grit. This is a massive, medium to coarse grained pebbly sandstone and forms the escarpment and gently inclined Cromford Moor to the east of Wirksworth.
A.bove the Ashover Grit, dark grey muds tones and shales occur and these in turn are succeeded by massive medium grained sandstones and micaceous siItstones of the Chatsworth Grit.
3.2.3 Geology of the Ecclesbourne Valley
The river Ecclesbourne runs through a narrow strip of alluvium over the shales of the Millstone Grit Series (Figure 3.5). To the north east, the higher ground is composed of the Ashover and Chatsworth Grits. To the south west, below the Namurian Shales, the Widmerpool Formation occurs. This consists of calcareous mudstones, thin limestones and calcareous sandstones. This formation is succeeded unconformably by the following rocks of Permo-Triassic age* Pebble- beds, the Waterstones and the Keuper Marl. As their names imply, these consist of pebble beds and coarse sandstones, siltstones and marls respectively.
A number of outliers of the pebble beds also occur in the area of Namurian shales north of the main outcrop. Areas of boulder clay occur in the river valley, and at the south eastern end a few small river terraces have been formed. Figure 3.5 Simplified Geology of the River Ecclesbourne Catchment -136-
Key to Figure 3.5
Alluvium - j •• River Terraces •Recent Deposits Boulder Clay Pebble Beds -Permo-Triassic Ashover and Kinderscout Grits Namurian Shales Widmerpool Formation m (calcareous mudstone & thin limestone bands) Carboniferous Matlock Limestone
iii Hoptonwood Limestone i. •. > TZ Dolomitised limestones of I •• I •• I Hoptonwood & Matlock groups Doleri te Igneous Rocks Vent Agglomerate Mineral Veins •q Built-up Area
Bo^iJt Ow -XG-s st^ul- MS. andI Swv'.W <1 (nui) -137-
3.2.4 Mineralisation and Mining
The limestone north of Wirksworth is heavily mineralised and has been extensively mined. The principal vein mineral is galena, though other minerals recorded from the area include cerussite (PbCOg), pyrite, sphalerite, calamine (ZnCO^), fluorite , calcite, baryte, ochre and "wad"
(Mn02). (Smith et al 1967). Galena was the mineral of main economic interest to the miners, though sphalerite, calamine and ochre were important sub- sidiaries (Ottery 1969). The Dove Gang Vein, and the Gulf Fault Veins and Yokecliff Rake were prob- ably the richest veins in terms of the quantity of lead produced.
The ore bodies occur as
i) veins varying in size from large major ore bodies to minor mineralisation on joint planes (serins)
ii) replacement deposits
iii) cavity in-fillings
The major veins generally have an easterly trend and many are intruded along steeply dipping faults. The smaller veins often follow joint planes and may form intersecting serins. The veins often cut the lavas but the extent of the mineralisation is usually reduced. -138-
Irregular replacement deposits, termed flats, roughly follow the dip of the rocks. They are mostly initiated around intersecting serins and their deposition is controlled by the bases of the impervious lavas, clays, shales and dolomite masses (Smith et al 1967) . Cavity in-fillings occur in pre-mineralisation cavities and post-mineralisation solution cavities where ore bodies have been red- uced to a clayey rubble. They can also occur along fault planes. »
Lead mining in the area is thought to date back to Roman times, though the evidence is incon- clusive (Ford and Rieuwerts 1968). There are, however, records of lead mining at Wirksworth from Saxon times (approx. AD 714), and the town is men- tioned in connection with lead mining in the Domesday Book (Kirkham 1968) . The peak of lead production was reached in the 18th century, in particular the 1780*s. It then declined slowly and steadily, and. large scale mining in the vicinity of Wirksworth ceased in the latter half of the 19th century. This decline was related to the falling price of lead and the increase of mining costs due to drainage problems associated with deep mining (Ottery 1969) .
3.2.5 Mine Drainage and Lead Smelting
The mines were drained by soughs (large drain- -139-
age adits). The two major ones were the Cromford Sough (SK 295568), draining the western group of mines, and the Meerbrook Sough (SK 327552) which drained mines further east. This sough was later extended to drain mines to below the level of the Cromford Sough. Both soughs drain into the River Derwent with a resultant lowering of the water table and a reduction of the volume of water entering the River Ecclesbourne (Ottery 1969). Other smaller soughs drain into the Ecclesbourne and their loc- ation is shown in Figure 3.4 and their names listed in Table 3.4. These and a number of other soughs, whose exact location is now unknown, have been listed by Rieuwerts (1966) and (1969).
Five cupola lead smelter sites are situated in the vicinity of Wirksworth (Ottery 1969) . However, only the Washgreen Cupola (SK 295538) - (site C, Figure 3.4) is close to the Ecclesbourne. This works ceased operation in about 1825 when the site was used for a dyeworks. Since World War I there has been a farm at this locality (Willies 1969)• Three bolehill smelter sites are also located in the area (Taylor 1968) and these are shown in Figure 3.4 (sites B1 - B3).
3.3 The Rowberrow Bottom Catchment
3.3.1 General Desciption
The valley of Rowberrow Bottom lies between -140-
Table 3.4
Names and Locations of Soughs Draining into the Ecclesbourne Catchment
Name NGR Ref. to Fig.3.4
Lees SK 288535 S 1 Warmbrook SK 287534 S 2 Hannage SK 288533 S 3
NGR - National Grid Reference Source of Data s Rieuwerts (1966) and (1969) -141-
the village of Shipharr. to the south west and Rowberrow Warren and Dolebury Warren to the north east. The stream flowing through the Bottom is small, being just over 4 km in length. It rises in an area of marshy ground about 500 m north west of Tynings Farm (ST 470565) and flows north westwards until it disappears underground adjacent to the road (A38) Figure 3.6 (ST 447593).
The valley is narrow with moderately steep sides, which become very steep indeed close to Dolebury Warren. The stream first runs through thick coniferous woodland for 1 km. A thin strip of mixed woodland then persists on either bank until a sharp turn westwards is made at the base of Dolebury Warren. From here the woodland continues on the southern and western bank of the stream only.
2 The catchment area is approximately 4.8 km . The stream is not gauged at any point and hence no flow data is available.
3.3.2 Geology of the Area Surrounding Rowberrow Bottom
As can be seen from Figure 3.7 the stream rises in the Carboniferous Lower Limestone Shale on the southern limb of the Blackdown Pericline. The stream then flows northwards across the fold to disappear close to the junction of the Black Rock Limestone and the Burrington Oolite on the northern limb. -14 2-.
Chuichill Upper Langford
Dolebur.y Warren
Roberrow Warren Shipham 9 S Holloway I Rocks (
0 Scale
Tynings Farm
Figure 3.6 Drainage"Plan of Rowberrow Bottom
® Stream sample site
H Soil sample site ( PWf \ SI Built-up Area -143- Fiq 3.7 Simplified Geology of the Area Surrounding Rowberrow Bottom Head Keuper I*larl -Triassic Dolomite Conglomerate /Clifton Down Limestone /Burrington Oolite Carboniferous ESP /Black Rock Limestone /Lower Limestone Shale v77Z /Portishead Beds -Upper Old Red Sandstone i v v v^/Buil t-up Area H K\y y-^xMineraW l Veins -144- Th e succession encountered is listed in strati- graphic order below. The principal features of each lithology are also given. Detailed accounts of local variations within lithologies, largely unim- portant to this work, are contained in Green and Welch (1965). i) Portishead Beds (Upper Old Red Sandstone) This is a feldspathic and often quartzitic red-brown sandstone containing layers of quartz conglomerate interbedded with bands of red and purple coloured micaceous sandy mudstone. In the lower part of the succession lenticles of quartz conglomerate are developed. ii) Lower Limestone Shale (Carboniferous) This consists of grey green shales with local developments of crinoidal and oolitic limestone. iii) Black Rock Limestone (Carboniferous) This is a dark grey to black fine grained crinoidal limestone. Two horizons character- ised by chert occur at 30 m and 150 m above the base of the limestone. The top of the limestone in this area is dolomitised. iv) Burrinqton Oolite (Carboniferous) Massive light grey oolitic and crinoidal -145- oolitic limestone. The remainder of the Carboniferous succession is: v) Clifton Down Limestone vi) Hotwells Limestone vii) Dolomitic Conglomerate (Triassic) This is a breccia or conglomerate largely composed of fragments of Carboniferous lime- stone, and locally Old Red Sandstone, cemented in a matrix of sandy marl or fine grained lime- stone debris. Within this area considerable dolomitisation has taken place, causing hyd- ration of the haematite present to limonite, imparting a yellow colour to the rock. About 200 m to the south of Holloway Rocks the uncon- formable junction of the Conglomerate with the underlying Old Red Sandstone is exposed. Less than 1 km to the west of Rowberrow Bottom, the Dolomitic Conglomerate is heavily mineralised with zinc (calamine) and to a lesser extent lead (galena) and forms the well known Shipham ore field. Four small veins are indicated on the geological map for Cheddar (sheet ST45) outcropping in the Bottom itself. Close field examination of the outcrop" at Holloway Rocks -146- revealed only one possible vein, the others were not located. The stream sediments are composed largely of red sand and silt. Black manganese oxide •coatings are commonly present on the larger pebbles and rocks in the stream bed. 3.3.3 Outline History of Mining in the Shipham Orefield Mining began in the Mendips in Roman times and went on intermittently up to the beginning of the 20th century. Detailed information about the work- ings is remarkably scarce, however, with few if any mine plans or maps of the orefield. Most of the mining areas today remain as "gruffy grounds" which are waste areas covered with grass, bracken and gorse, and consisting of a maze of crop workings and old shafts interspersed with dumps of mine debris (Green 1958). Gough (1967) has written a general account of the history of mining in the Mendips. He records that a calciner was located in Rowberrow Bottom. This was used to convert the calamine ore mined at Shipham to zinc oxide, and operated in the late 18th century. In the mid to late 19th century ochre was worked in the hill of Dolebury Warren. The ochre was washed in a small oblong walled enclosure formed by damming -147- the stream in Rowberrow Bottom below Rowberrow Church (Gough 1967). No evidence of this operation exists today, however. 3.3.4 Sources of Contamination in Rowberrow Bottom The mineral veins outcropping in the Bottom provide an intense but localised source of Pb, Zn and Cd contamination. In the vicinity of Shipham and the associated orefield the soils are heavily contaminated by these elements (sites 6-10 Figure 3.6 and Table 3.5) (Marples 1979). A soil profile examined by Marples (1979) on the eastern bank of the stream (site P Figure 3.6) also revealed considerable contamination by Pb, Zn and Cd (Table 3.5). It is thought that the profile is located on the site of the calciner (see above). -148- Table 3.5 Levels of Heavy Metals in Soils from Rowberrow Bottom Site No. Cd Pb Zn NGR 6 800 4,500 62,400 ST 451578 7 95 1,375 5,500 ST 452580 8 40 1,500 1,750 ' ST 455580 9 40 2,125 3,250 ST 455576 10 150 9,250 18,000 ST 460571 All >ig/g dry weight Surface soil 0 - 15 cm Soil Profile P (ST 459570) Depth (cm) Cd Pb Zn 0-10 299 8,000 36,400 10 - 25 428 10,400 42,000 25 - 30 432 13,600 21,600 30 - 35 1,680 14,400 50,000 35 - 60 484 12,400 24,000 60 -100 328 10,400 26,000 NGR - National Grid Reference Data reproduced by kind permission of A. E. Marples. -149- CHAPTER 4 GEOCHEMICAL RECONNAISANCE 4.1 Introduction This work was undertaken in order to make a detailed assessment of the geochemistry of the catch- ments selected using the Wolfson Geochemical Atlas, so as to determine their suitability for futther study. The choice of methods was largely governed by the following criteria: i) The desire to provide geochemical data complementary to those provided by earlier studies within the Applied Geochemistry Research Group, such as Aston (1974), Watling (1974) and Mill (1976). ii) To provide data comparable with those being obtained by related projects being undertaken at the time by other Group members. iii) To confirm and supplement the information contained within the Wolfson Geochemical Atlas of England and Wales (Webb et al 1978). 4.2 Collection of Stream Sediment Samples Additional sites were chosen in each area to supplement those of the Wolfson Geochemical Atlas -150- and to provide a more comprehensive picture of the geochemistry of each catchment. Sites sampled during the compilation of the Wolfson Geochemical Atlas were also re-sampled. The following criteria were observed in the selection of each new sampling sites i) Sites were selected on each tributary upstream of the confluence of two streams. ii) To avoid the effects of local contamination, samples were taken upstream, preferably by a distance of at least 200m, of villages, road bridges, effluent discharge pipes etc. Locally, care was taken to avoid areas of collapsed bank material, cattle crossings and land drains. Drainage maps displaying the location of sample sites in each area are shown in Figures 4.1, 4.2, and 3.6. Samples of active stream sediment were collected by hand or by using a small plastic mug, from the centre of the stream, and placed in labelled Kraft "wet-strength" paper bags. It was found necessary to collect between 250g and 500g of sediment to provide sufficient -200 pm material for analysis, as in most cases the streams sampled were rapid flowing with mainly coarse grained sediments. Accumulations of organic debris and litter were avoided where possible. -152- Duf field -153- 4.3 Analysis of Stream Sediment Samples Samples were oven dried in bags at a temper- ature of c. 105°C for a period of between three and four days. The dried material was then carefully disaggregated, without crushing, in a porcelain mortar. The -200 fraction was separated using nylon sieve cloth mounted in a plastic frame. Following sample digestion, using a hot nitric * acid attack (see Appendix 1) the concentrations of Cu, Pb, Zn, Cd, Fe, Mn, Ca and Mg were determined using a Perkin-Elmer model 403 atomic absorption spectrophotometer with an air-acetylene flame. Tables 4.1 and 4.2 give the resonance lines used, the instrument sensitivities and detection limits for each element. For calcareous sediments, a calcium correction was applied to the concentrations measured for Pb, Zn, and Cd (see Appendix 5) . To suppress chemical interferences in the analyses for Ca and Mg, the sample solutions were diluted in the ratio of one to ten with a solution of 0.5% lanathanum oxide in one molar hydrochloric acid (HC1). 4.4 Collection of Stream Water Samples Water samples were taken only at selected "key" sites to give an outline of the pattern of heavy metal dispersion within the stream or river water in each catchment. This vas done to reduce * A mWk auA uoav ckosi*) asW «. ra.f'id. Cr<_o cKc^lsY* ^ Cvovaf , -154- Table 4.1 Resonance Lines, Sensitivities and Detection Limits for the Perkin-Elmer 403 Atomic Absorption Spectro- photometer Element Wavelength Sensitivity Detection n. m. 1% Absorption Limit yg/ml pg/ml Cu 324.7 0.15 0.005 Pb 283.3 0.70 0.03 Zn 213.8 0.025 0.002 Cd 228.8 0.04 0.004 Fe 248.7 0.15 0.01 Mn 279.5 0.10 0.005 Ca 422.7 0.09 0.002 Mg 285.2 0.01 0.0003 (Perkin--Elmer 1971) Table 4.2 Detection Limits for Stream Sediment Analyses, Nitric Acid Attack Element Detection Limit Cu 0.2 Pb 2.0 Zn 0.1 Cd 0.1 Fe 0.1 Mn 0.2 Units t pg/g -155- the workload at this stage, since the analysis of large numbers of water samples is very time consuming. One litre high density polyethylene bottles were used for the collection of water samples. The bottles were cleaned before use by filling them with 10% v/v nitric acid (HNOg) and leaving them to stand for at least 24 hours. They were then emptied, rinsed three times with de-ionised water (DIW) and stoppered. At each site, the sample bottle was rinsed twice with stream water prior to being filled and sealed. Samples were taken from the centre of the stream, at a point just below the water surface (Levinson 1974). The precautions observed for the collection of the stream sediment samples to avoid local contamination were applied to the water sampling. Particular care was taken to ensure that any fine material brought into suspension by the action of walking in the stream or by the collection of sediment samples did not enter the sampling bottles. Thus water sampling was com- pleted before stream sediment sampling. Two separate one litre samples were taken at each site, one was acidified immediately to pH<2 by the addition of 5ml of concentrated HNO^, and the other left untreated. The latter sample was used for the determination of the "filtrable" fraction of the -156- heavy metals, and the former for the "total" heavy metal concentration. The concentration of the metal associated with the suspended particulate matter in one litre of water is then equal to the concentration of metal in the "total" determination minus that in the "filtrable". The terms "filtrable" and "non- filtrable" have been adopted in preference to "dissolved" and "un-dissolved", following the recom- mendations of the American Public Health Association (1971) and the Water Research Centre (Cheeseman and Wilson 1973, Wilson 1976). The pH of each sample was determined in the field using a Pye Unicam model 293 pH meter. 4•5 Analysis of Stream Water Samples Unacidified water samples were returned to the laboratory for filtration as soon as possible after collection. This was done in order to minimise the loss of metals from solution by adsorption onto container walls and to minimise the interaction between dissolved metals and suspended particulates. The samples for the "filtrable" determinations were filtered under vacuum through acid washed GF/C filters (pore size 0.5-1.0 ^um). The sample bottle was rinsed with a small volume of DIW (c. 50ml) to remove any residual particulate matter and the filtered sample returned to it. The sample was then acidified to pH<2 with 5ml of concentrated HNO^. -157- This procedure stabilizes the concentration of trace elements within the samples for at least 30 days (Elderfield 1971, Watling 1974). Any metals adsorbed from solution onto the container walls prior to filtration are also leached and returned to sol- ution in the acidified sample. Samples acidified in the field for "total" metal determinations were allowed to stand for four days before filtration. This period is re- commended as sufficiently long to leach available heavy metals from the particulate matter (Watling 1974, AGRG 1975). The filtration apparatus was rinsed between successive samples with 10% v/v HN03 followed by DIW. Filters were washed in 10% v/v HNO^ and subsequently twice with DIW before use. Filters were handled with blunt ended plastic forceps to minimise contamination. For the determination of Ca and Mg an aliquot of 2ml of water was taken from the acidified filtered samples and diluted with an equal volume of lanthanum solution prior to determination by AAS. Prior to trace element analysis by AAS, water samples were pre-concentrated by chelation solvent extraction (see Appendix 1). Extracts were analysed for Cu, Pb, Zn, Cd, Fe, and Mn using a Perkin-Elmer model 403 atomic absorption spectrophotometer as -158- before. The detection limits for the method are from AGRG (1975) and are quoted in Table 4.3. The reagents used in all aspects of the analysis of the sediment and water samples were of BDH "AnalaR" gradfe, and DIW was used throughout for rinsing glass- ware and diluting reagents. All glassware was cleaned thoroughly before use by successive washing in 5% v/v "Decon" solution, 10% v/v HN03 and DIW. Sample Contamination Control determinations were performed at regular intervals, approximately one every tenth sample, throughout the analytical programme to determine the extent of contamination due to reagents, glassware or DIW. For the analysis of water samples, the procedure followed was simply to substitute one litre of DIW in place of a sample. Control digestions were performed for stream sediment analyses. A control value determined for a particular element was subtracted from a sample result if the value of the control constituted 10% or more of the de- termined result.' Table 4.4 gives the mean values of controls determined throughout the analysis of the reconnaissance samples. To ensure the correct operation of the solvent- extraction procedure, one litre samples of DIW, spiked with known concentrations of the metals of -159- Table 4.3 Detection limits for Water Analyses Following Solvent. Extraction Element Detection Limit Cu 0.5 Pb 0.4 Zn 0.4 Cd 0.2 Fe 1.6 Mn 2.0 (AGRG 1975) Units t Jig/1 Table 4.4 Mean Concentrations of Metals in Control Analyses Cu Pb Zn Cd Fe Mn n Stream Sediments N.D. N.D. 1.1 N.D. N.D. N.D. 15 (pg/g) Water 0.2 0.1 0.9 0.3 3.0 N.D. 12 (yg/D n = number of determinations N.D. = element not detected Table 4.5 Mean Percentage Recoveries from Spiked Samples of DIW Cu Pb Zn Cd Fe Mn n Mean Recovery 95 83 100 98 92 94 8 S.D. 2.7 16.7 2.5 1.6 13.6 9.8 C.V.(%) 2.8 20.1 2.5 1.6 14.8 10.4 S.D. = Standard Deviation C.V. = Coefficient of Variation n = Number of Determinations Concentration of added metals = 10 metal/l -160- interest, were analysed periodically. This was usually done at the beginning and end of each batch of SDDC/buffer solution. The mean percentage re- coveries for eight spiked samples are given in Table 4.5. 4.7 Results and Discussion The stream sediment data for Minsterley Brook for Pb, Zn, and Cd, the major contaminants in the system, are given in Table 4.6 for mainstream sites and for three control sites. The data for Pb has also been plotted in Figures 4.3 and 4.5 to illustrate the major trends, common to all three elements. The full data listing, sediment and water, is given in Appendix 3. It is evident from the results that the sediments of Minsterley Brook, particularly in the upper reaches, are heavily contaminated with Pb, Zn, and Cd. High levels of Cu also occur here - see data in Appendix 3. The sediments are still contaminated, compared with control sites, as far downstream as site 134, some 20km from Gravels, the major source of heavy metals. These data confirm those of the Wolfson Geochemical Atlas. The chief sources of contamination are the mine workings and mineralisation at Gravels, although further inputs to the system come from tributaries draining other disused mines to the east, see Figure 4.3. A secondary source of contamination partic— -161- Table 4.6 Pb, Zn and Cd Concentrations in Stream Sediments from Minsterley Brook . Mainstream Minsterley Brook Control Sites Site Pb Zn Cd Site Pb Zn Cd 131 1348 839 4.8 2 200 224 0.8 129 108 264 2.3 132 104 208 2.0 33 20800 15600 137 135 76 260 1.2 31 22800 28000 236 30 15108 20000 164 28 5680 8800 94 128 5668 6239 42 21 6148 4319 30 107 4120 5200 41 17 3400 4040 34 10 8400 5400 41 9 3160 2760 19 3 1720 1760 12 125 580 639 4 126 508 591 3.5 133 640 712 4 134 680 920 8 Units s yg/g ZfM! Rta Brook Jl |lO C m—i U> Pontesbury Pb in Stream Sediments — Fig 4.3 Minsterley Brook ppm Pb • <100 • 100-300 I 0 301-600 | % 601-1000 £ 1001-2000 0 1 2km ^ >2000 -163- ularly evident from the dispersion plot (Fig 4.5) and common to all three elements occurs at site 10. This probably relates to the ore dressing plant that formerly occupied the adjacent land (Chapter 3). • The data for the filtrable and total exchangeable metals in water samples are given in Table 4.7. The data are also illustrated for filtrable Pb in Figures 4.4 and 4.5. The extent of the contamination of the stream water in this area by heavy metals is similar to that found in the sediments. The water of Minsterley Brook is heavily contaminated with Pb, Zn and Cd and the concentrations of Pb and Zn remain elevated above control site concentrations at site 134. Apart from those draining mines in the head- waters of the Brook, the majority of tributaries in the system show little contamination. The secondary peak occurring in sediments at site 10 is also re- flected in the waters. Figure 4.5 illustrates the dispersion of Pb for all three phases in the mainstream of Minsterley and Rea Brook. Zn and Cd follow similar patterns. The patterns of decay of metal concentration with distance from the metal source are well defined, with the mines and mineralisation at Gravels acting together as a point, source of contamination to the system. The other contaminated tributaries in the headwaters of Minsterley Brook appear to have little -164- Table 4.7 Filtrable and Total Pb, Zn and Cd Concentrations in Minsterley Brook Water Filtrable Total Site Pb Zn Cd ' Pb Zn Cd 131 3 25 1.2 N.S. N.S. N.S. 129 3 100 0.8 6 40 0.7 33 19 1430 21.0 110 1430 23.0 31 N.S. N.S. N.S. 128 2130 25.0 30 25 1900 21.5 48 1880 22.0 28 15 800 10.0 14 7 20 10.0 107 7.5 695 5.7 11 690 6.8 10 25 500 3.4 27 420 3.3 9 11 250 1.3 16 223 1.5 3 8 250 1.0 13 153 1.5 126 13 150 1.6 16 150 1.1 134 9 108 0.7 9 260 5.1 Control Sites Filtrable Total Site Pb Zn Cd Pb Zn Cd 2 2.5 116 0.4 5 40 3.5 132 2.5 40 0.9 5 100 0.5 135 2.5 50 0.9 5 115 0.6 Units : yg/1 N.S. - no sample Shr#w»bury /Rea Brook I ID C —) 0) jMinsterley Pb in Stream Water Fig L.l.j Minsterley Brook I Minsterley ppb Pb • <5 Brook | • 51-10 1 0 10-1-25 # 25-1-50 2km 0 50-1-100 ° 1— 0 >100 •f1 Vv -167- impact upon these patterns. The situation apparent in Minsterley Brook makes the system particularly suitable for the purposes of this study. Table 4.8 gives the sediment concentrations of Pb, Zn, and Cd in Rowberrow Bottom. The data are illustrated for Cd in Figure 4.6. The contam- ination of the sediments below site 226 with Pb, Zn and Cd is considerable. The mineral veins at Holloway Rocks and the contaminated soils (Chapter 3), account for this. The levels of metals in the sedi- ments increase downstream, however, falling slightly at site 231 close to the point where the stream disappears. This pattern of metal dispersion makes this stream unsuitable for further study in the context of this project. The results for the water, Table 4.9, are rather ambiguous owing to the onset of heavy rain whilst the water samples were being collected. As the stream is short and drains steep sided limestone terrain, it responded rapidly to the increased surface run-off and rise in ground-water levels. The turbidity of the water increased markedly as the stream rose, reflecting the increased suspended solid load. This effect is demonstrated by the large increases in total metal compared with fil- trable metal shown in Figure 4.6. Water samples at site nos. 206, 230, 226 and 231 and all the stream -168- Table 4.8 Pb, Zn and Cd Concentrations in Stream Sediments from Rovberrov Bottom Site Pb Zn Cd 230 40 . 463 5.2 226 116 304 4.8 228 4280 11400 116 227 2440 10400 92 229 8000 17600 188 231 3308 14399 132 Control Site 206 64 148 2.0 Units s Table 4.9 Filtrable and Total Pb, Zn and Cd Concentrations in Water from Rowberrow Bottom Filtrable Total Site Pb Zn Cd Pb Zn Cd 230 2.5 22 0.7 N.S. N.S. N.S 226 3.5 20 1 .0 2.5 40 1.6 228 2.5 30 0.7 19 80 2.0 227 18.0 259 4.3 172 520 8.2 s r C O 229 23.0 310 • 500 1840 26 231 5.0 80 1.6 70 360 6.2 Control Site 206 2.5 66 1 .9 5.0 26 2.4 Units : yg/l N.S. = no sample -169- j » Fig £.6 Cd Dispersion in Sediments and Water Rowberrow Bottom -170- sediment samples were taken during the dry weather immediately preceding the storm. Thus heavy rain- fall following a period of dry weather coupled with a rapid increase in discharge can produce a pulse in the total metal concentrations related to the increased suspended sediment load. Clearly this phenomenon must be considered*in planning water sampling regimes and in the interpretation of hydro- chemical data. Stream sediment and stream water data for Pb, Zn, and Cd for the River Ecclesbourne are contained in Tables 4.10 and 4.11. Figures 4.7 and 4.8 illus- trate the distribution of Zn in sediments and waters respectively. Figure 4.9 illustrates the dispersion of Zn in the sediments, filtrable metal and total exchangeable metal phases. Similar patterns are exhibited by Pb and Cd. The drainage pattern within the Ecclesbourne catchment is far more complex than in the other areas investigated. Apart from the two "feeder" tributaries in the north, however, the others joining the main stream are uncontaminated as far as can be ascertained from the data. Stream sediment concen- trations of Pb (1000 Jig/g) , Zn (520 ^ig/g) and Cd (4 yg/g) at the lowest site sampled (327) are still elevated above those^j found at the control sites 331 and 332. (Site 331 j Pb" 56 yg/g, Zn 87 yg/g, -171- Table 4.10 Pb, Zn and Cd Concentrations in Stream Sediments from the River Ecclesbourne Site Pb Zn Cd 315 538 512 10.8 344 3480 1640 26.4 318 19200 1760 32.0 328 100*00 1360 19.2 321 9600 1080 12.4 324 3600 1360 16.0 336 5120 600 6.4 325 1560 544 5.6 327 1000 520 4.0 Control Sites 331 56 87 1.6 332 64 112 2.0 Units : yg/g Table 4.11 Filtrable and Total Pb, Zn and Cd Concentrations in Water from the River Ecclesbourne Filtrable Total Site Pb Zn Cd Pb Zn Cd 315 3.5 88 4.0 28 113 4.4 318 5.0 111 2.0 30 145 3.2 328 5.0 74 1.3 24 101 2.4 321 5.5 46 0.9 22 69 1.6 324 5.0 38 0. 8 18 59 1.4 325 4.0 35 1.0 14 49 1.3 327 3.5 28 1.7 14 51 1.7 Control Sites 331 2.5 16 0.7 7.0 40 2.1 332 2.5 28 1.6 4.0 20 1.0 Units i ^g/l -173- iWirksworth Zn in Stream Water- River Ecclesbourne ppb Zn • 420 • 21-30 • 31-50 '0 51-100 ^ >100 Fig L8 f N 2km Duffield -174- sample sites (L___l_Jkm Fig L.9 Zn Dispersion in Sediments and Water- River Ecclesbourne -175- Cd 1.6 ug/g). Metal levels in the water at site 327 are comparable with control site concentrations. For example, at site 327 filtrable Zn is 28 )ig/l and filtrable Cd is 1.7 yg/l compared with 16 ^g/l Zn and 0.7 yg/\ Cd at site 332. Both the feeder tributaries of the Ecclesbourne receive drainage from a number of mine soughs and this accounts, at least in part, for the high levels of metals encountered. Contributions to the metal burden of the western stream would also be received from contaminated ground-water and run-off from the mineralised area immediately to the north. Addition- ally in the eastern tributary great difficulty was experienced in avoiding the large amounts of domestic rubbish that litter the stream for much of its length. Of greater importance though, are the high concentrations of Pb, Zn and Cd in the water and stream sediment associated with site 318, which mostly exceed those at the above mentioned local- ities. Closer examination of the area revealed that effluent from the Wirksworth Water Reclamation Works (WRW) entered the stream from a pipe 150m above site 318. The effluent was not sampled on this occasion and further work, (Chapters 6 and 7), investigated the impact of the effluent on local concentrations of heavy metals in the river. From site 318, concentrations of Pb, Zn and Cd in the sediments decay steadily with distance -176- downstream. Total Pb shows an erratic decay from a peak concentration at site 318. Filtrable Pb remains virtually unchanged in concentration through out the entire length of the stream. This obser- vation may be significant and indicate a tendency for Pb to be associated with suspended particulates in river water (Yates 1978). ' The water pH of Minsterley Brook and the Ecclesbourne varies between 6.5-8.5, Table 4.12. Concentrations of Ca and Mg (Table 4.12) in both rivers are indicative of •'hard" water regimes. The analytical methods used were suitable for this work. The nitric acid attack is rapid and straightforward to perform. The technique of water analysis, although time consuming, was also adequate. The recoveries of metals from the spikes are good, with the exception of Pb. Watling (1974) also noted that this element had a poor recovery. This is partly due to the poor analytical sensi- tivity of Pb in flame AAS analysis and the inter- ference by other elements which are often present in equal or higher concentrations. The blank deter- minations indicate no significant levels of contam- ination due to reagents or apparatus. An undesirable feature of the method for obtaining the concentration of non-filtrable heavy metals was noticed from the results. In several -177- Table 4.12 Filtrable Ca and Mq Concentrations and pH of Water from Minsterley Brook and the River Ecclesbourne Minsterley Brook Site Ca Mg pH 131 18 4.8 7.1 129 33 7.4 6.9 33 57 8.4 6.8 30 58 7.4 6.9 28 53 8.0 7.2 107 54 6.6 7.5 10 54 8.8 8.0 9 82 13.0 8.0 3 83 13.2 8.3 126 78 12.0 8.5 134 97 16.0 8.6 River Ecclesbourne Site Ca Mg pH 315 49 6.2 7.0 318 78 9.8 7.2 328 66 9.0 7.0 321 54 9.0 7.1 324 52 8.8 7.0 325 52 8.8 6.8 327 60 11.0 7.0 Units : Ca , Mg pg/ml -178- instances, total determinations yielded concentra- tions of metals less than those in the respective filtrable samples. Even allowing for an occasional error in labelling sample bottles in the field, the feature was persistent, as for example with Zn in the Minsterley samples which had low suspended solids concentrations. It is not possible to say specifically where the error lies, although the situation could be avoided by determining the non- filtrable metal fraction by a direct method of an- alysis rather than indirectly, by difference, as in this case. 4.8 Conclusions The broad patterns of trace metal distribut- ion in the waters and stream sediments of the three catchments studied were established. Stream sedi- ments and waters containing anomalous concentrations of heavy metals with respect to control sites were found in each area. In particular, anomalies found in the stream sediments of the Minsterley Brook — Rea Brook system and the River Ecclesbourne confirm patterns established by the Wolfson Geochemical Atlas of England and Wales. Minsterley Brook and the River Ecclesbourne both have single, well defined, major sources of heavy metal contamination, though a number of minor sources are also evident. Dispersion patterns of -179- decreasing concentration with distance downstream from the major source of metals are well defined for Pb, Zn, Cd (and Cu) in the stream sediments and the waters of Minsterley Brook and the River Ecclesbourne. However, the sources of metals and their dispersion patterns are not so clearly de- fined in Rowberrow Bottom. This is due to the short length of this stream and the extensive con- tamination of the bank soils within the valley for almost its entire length. The River Ecclesbourne and Minsterley Brook were both considered suitable areas for continued, more detailed study, in the context of this project. No further work was con- sidered for Rowberrow Bottom. The procedure employed for the determination of the non-filtrable metal concentration appeared unsuitable. This was apparent in the uncertainty in a number of the results obtained and the addi- tional sample handling and analysis required to analyse two samples from each site. Finally, the results from Rowberrow Bottom illustrated the effects of weather and stream discharge upon the concentrations of heavy metals in water. -180- CHAPTER 5 A COMPARISON OF FILTER TYPES AND METHODS FOR THE DETERMINATION OF HEAVY METALS IN SUSPENDED PARTICULATE MATTER 5.1 Introduction The results of the reconnaissance work revealed several deficiencies in the methods of filtration used and the determination of concentrations of heavy metals in suspended matter. These were* i) A number of meaningless results (i.e. negative) were obtained for the concentration of metals in the suspended solid phase, due probably to interactions between dissolved metals and suspended particulates in the sample during storage before filtration (Thorne 1980, pers. comm.). ii) The relatively high ratio of filter weight to that of the material collected meant that weights of particulate were not easily obtained. Difficulty was also encountered in obtaining a constant weight for the dry filters, iii) The large and indefinite pore size of GF/C's makes the comparison of results with other published work difficult, iv) GF/C filters by nature of their construction make a large surface area available for the adsorption of heavy metals in unacidified samples. -181- v) Two water samples have to be collected at each site, this doubles the time required for an already lengthy analytical procedure. In view of these criticisms, membrane filters were investigated as an alternative to GF/C filters. The following features of 47 mm diameter, 0.45 jam pore size Sartorius cellulose nitrate membranes and Whatman GF/C filters were examined: i) Total metal content of the filters as determined by complete digestion. The results of Mill (1976) for GF/C's were used for comparison in this instance, ii) The extent to which metals may be leached from filters during the passage of water samples and the effects of dilute acid as a cleaning agent. iii) Qualitative comparison of filtration rates including 0.4 pore size Nuclepore filters, iv) Methods for the determination of metals in the particulate phase were also investigated and compared. Sartorius filters were chosen in preference to Millipore purely on the grounds of cost, the former being considerably less expensive. Chemical investigations were not made on the Nuclepore filters as they were rejected on the basis of their slow filtration rate, see below. -182- 5.2 Experimental Methods 5.2.1 Total Digestion of Membrane Filters Filters were placed in 50 ml stoppered Erlen- meyer flasks and digested in a mixture of concen- trated HN03, 1 ml of concentrated H2S04 and 1 ml of DIW. Initially the filters formed a gel which rapidly dissolved on warming. The flasks were heated on a hot plate until all the S03 vapour had been driven off and a white powdery residue remained. This residue was dissolved in 5 ml of 1M HCL and the solutions analysed for metals by flame AAS. Filters were washed by soaking in 10% v/v HNOg followed by several rinses in DIW. All re- agents used were of BDH AnalaR grade and blunt ended plastic forceps were used for handling the filters. Reagent contamination was checked on control determinations and suitable corrections have been applied to the results to account for this. 5.2.2 Leaching of Heavy Metals from Filters The results of the total digestions and the reports of several workers e.g. Mill (1976) and Zirino and Healy (1971), indicate that filters should be acid washed before use. The following experiments were therefore conducted only on acid washed filters. One litre aliquots of DIW were passed through GF/C and membrane filters and then analysed for -183- heavy metals. Similarly, 11, aliquots of DIW acidified to pH <,2 with 5 ml of concentrated HNO^ were also filtered and analysed as above. DIW both direct from the supply and acidified with HNO^ were also analysed to determine background metal levels. 5.3 Determination of Heavy Metals in Suspended Particulates 5.3.1 Comparison between the Existing Method and Wet Acid Digestion Two sets of six duplicate samples were collected from Rowberrow Bottom. One set of samples was acidified to pH <2 with 5 ml of concentrated HNO^ immediately after collection. They were left to stand for four days before filtration through acid washed GF/C's. Heavy metals were determined on the samples using the standard procedures already described. The second set of samples was filtered through acid washed membranes and returned to their original bottles. Metal concentrations were also determined on these samples. The filters were dried in a desiccator and then transferred to stoppered 50 ml Erlenmeyer flasks in which they were digested using the method described above. The extracts were analysed for heavy metals by flame AAS. Filters used in the experiment were all from the same batch and four control determinations were performed on acid washed filters alone. -184- 5.3.2 Comparison between the Existing Method and Cold Acid Leaching Three ten litre bulk water samples were collected from site 347 on the River Ecclesbourne. These were shaken well and split to givei i) 6 x 11 subsamples, filtered through membrane filters to yield a "membrane filtrable" metal value. ii) 6 x 11 subsamples, filtered through GF/C filters to yield a "GF/C filtrable" metal value. iii) 6 x 11 subsamples, acidified to pH <2 with HNOg and filtered four days later to give a « "total" metal concentration. The membrane filters were washed with 10% v/v HN03, rinsed with DIW and then dried to a constant weight before use. It is necessary to wash the membranes before weighing, as they are coated with a wetting agent which is removed during filtration. This can cause a weight loss of the same order as the weight of the collected material (Biscaye and Eittreim 1974) . Membrane filters also have to be moistened as, in a dry condition, they crease and may crack when placed under vacuum. After filtration the membranes were placed in numbered plastic petri dishes and dried to constant weight. The dried filters were carefully transferred -185- to 50 ml stoppered Erlenmeyer flasks and 5 ml of 0.5M HC1 added. They were then leached for one hour in a mechanical shaker. The leachates were poured into small test-tubes for analysis by AAS. Metal concentrations in the waters were determined following the standard procedures described already and control samples for reagertt contamination were also analysed. Total exchangeable metal concentrations in duplicate samples were compared using the two methods described above. Seventeen duplicate samples from various sites were collected throughout the seasonal sampling programme. One of these was acidified in the field to pH<2 and filtered through GF/C • s to give the "total" value as above. The other was filtered through Sartorius membranes which were leached with 0.5M HC1 as described above. Addition of the result obtained from the HC1 leach to the filtrable metal result gives the total exchangeable metal concentration of the sample. This value should be equivalent to the "total" value obtained from the acidified samples. The data from the two techniques were compared statistic- ally using a paired "t"-test. An indication of the reliability of the HC1 leach method and its compati- bility with the method used previously was thus obtained. -186- 5.3.3 Total Heavy Metals by Sample Evaporation and Acid Digestion Six subsamples of 200 ml were also taken from the bulk samples, acidified with 3 ml of concentrated HNO^i and evaporated to dryness in 250 ml beakers. Care was taken not to boil the samples. The residue was refluxed with a further 3 ml of concentrated HNO^ with a watch glass covering the beaker. The acid was then again taken to dryness with the watch glass removed. The final residue was taken up in 1M HC1 which was carefully washed down the sides of the beaker. The solutions were made up to 10 ml in volumetric flasks with extra acid and the metal content determined by AAS. 5.4 Results and Discussion The qualitative comparison of filtration speeds showed, as expected, that the filtration rate for the GF/C was considerably higher than for either of the other two filters considered. The filtration speed for the Sartorius membrane was, however, acceptable for the river water samples generally encountered. Samples with a high suspended solids load required several filters, approximately twice the number of GF/C's needed for similar samples. The filtration rate for the Nuclepore filters was prohibitively slow, with clogging occurring after several seconds even with relatively low particulate -187- concentrations. These observations reflect the differences in pore size and structure of the filters commented on in Chapter 2. The chemical data are given in Tables 5.1 - 5.10.* The contrast in the chemical composition of the two types of filter is very marked, particularly for Zn, Tables 5.1 and 5.2. The acid washed GF/C contains nearly 3% w/w Zn as opposed to only 15 ppm Zn in the unwashed and 8.7 ppm in the washed membrane filters. The effects of acid washing are evident for Cu and Zn in the membranes. Approximately 50% of the Cu and 40% of the Zn are removed by the acid, whilst the Fe content remains about the same (Table 5.1). Unfortunately, similar data are not available for the GF/C•s. The data in Table 5.3 show that sample contamination by the filters is only significant for Cu and Zn. Filtration of DIW (pH approximately 5.5) through acid washed filters removes twice as much Zn from GF/Cfs (4.3^ig/l) as from membrane filters (2.2 pg/1) and three times as much Cu (0.7 pg/l GF/C ; 0.23 ^jg/1 membrane). Levels of the other metals in the filtered water are generally the same as in the control sample of DIW. Although values are quoted for Pb (1.1 >Jg/l and 0.5 jug/l for the membranes and 0.5 pg/l for GF/C*s) these are very close to the detection limits of the method and are probably -188 - Table 5.1 Mean Metal Contents of Sartorius Filters Cu Pb Zn Cd Fe Mn n Unwashed 2.8 nd 14.8 nd 91.4 nd 6 Acid Washed 1.4 nd 0 . nd 93.6 nd 4 Units _= pg/g n = no. of replicates nd = none detected Table 5.2 Trace Metal Contents of Whatman GF/C Filters Cu Pb Zn Cd Fe Mn Acid Washed 4.5 7.9 29750 3.2 650 53 (pg/g) Table 5.3 Mean Metal Contents of Samples of DIW Cu Pb Zn Cd Fe Mn n Unacidified, through 0.23 1.1 2.2 0.2 3.3 0.3 4 Sartorius filters Acidified - Sartorius 0.33 0.5 1.4 0.3 2.8 nd 4 filters Unacidified - 0.7 0.5 4.3 0.3 2.2 nd 4 GF/C filters Unacidified - nd nd 0.6 0.3 2.3 nd 4 unfiltered Acidified - 0.2 nd 0.9 0.4 3.0 nd 4 unfiltered Units s= pg/l n = no. of replicates nd = none detected All filters acid washed -189 - not highly significant. The mobile fraction of the metals is very small when compared with total metal content of the filters, especially for the GF/C's. The relative contribution by the filters to the metal levels found in the river water samples generally encountered is small, with the possible exception of Cd, c.f. Table 5".3 with Tables 5.4A and 5.5. The results for the samples from Rowberrow Bottom (Tables 5.4A-E) clearly indicate the compar- ibility of these two methods for determining particulate metal concentrations. An obvious practical drawback to the wet digestion method is the large residual Fe and Zn contents of the filters themselves. This means that large numbers of control analyses have to be performed. Metal levels in filters may also vary a great deal between batches. The digestion is time consuming and prone to contaminationy particularly during the evaporation of the I^SO^. The good agreement between the results is surprising. Acidification of one litre of water with 5 ml of 16M HNO^ gives a solution which is + approximately 0.1 M with respect to H , assuming that the water has negligible buffer capacity and a pH of 7. This represents a very weak acid leach of the particulate compared with the effects of a total digestion, although the leaching period is quite long (four days). It could be concluded -190 - Table 5.4 Filtrable and Suspended Particulate Concentrations of Heavy Metals in Rowberrow Bottom Samples 5.4A Filtrable Metal, 0.45 yon Sartorius Membrane Site Cu Pb Zn Cd Fe Mn (pq/l) 230 0.5 <2.5 22 0.7 13.0 4.0 226 1.0 3.5 20 1.0 13.5 5.5 228 0.6 <2.5 30 0.7 12.5 5.0 227 0.6 18.0 259 4.3 35.5 7.5 229 2.4 23.0 310 4.8 80.0 37.5 231 0.4 5.0 80 1.6 9.5 2.5 5.4B Suspended' Particulate , by Wet Digestion Method Site Cu Pb Zn Cd Fe Mn (uq/1) 230 0.2 5.0 16.9 0v9 261 26 226 0.4 5.0 10.1 0.1 151 11 228 0.6 12.0 43 0.6 271 16 227 0.2 174 381 4.9 1411 73 229 8.6 498 1590 19.3 8016 444 231 1.2 50 161 1.4 681 24 5.4C Total Metal Concentration, by Addition of Table 5.4A + Table 5 . 4B Site Cu Pb Zn Cd Fe Mn (uq/1) 230 0.7 7.5 39 1.6 274 30 226 1.4 8.5 30 1.1 165 17 228 1.2 14.5 73 1.3 284 21 227 0.8 192 640 9.2 1447 81 229 11.0 521 1900 24.1 8096 482 231 1.6 55 241 3.0 3.0 27 -191 - Table 5i4 (contd.) 5.4D Total Exchangeable Metal Concentration, by Acidification to pH<2 Prior to Filtration Site Cu • Pb Zn Cd Fe Mn 230* — — — — — — 226 0.8 2.5 40 1.6 140 23 228 1.5 19 80 2.0 170 19 227 2.4 172 520 8.2 440 63 229 8.8 500 1840 26.0 1550 460 231 2.3 70 360 6.2 220 28 * Sample lost during analysis. Reagent and filter blanks subtracted from results. 5.4E Results of Paired "t"-test Comparing Table 5.9C with Table 5.9D Element Value of "t" Significance Cu 0.006 N.S. Pb 0.808 N.S. Zn 0.220 N.S. Cd 1.501 N.S. Fe 1.316 N.S. Mn 1.274 N.S. N.S. = no significant difference -192 - that the metals in the particulate are mainly in the non-residual phase and are thus susceptible to the weak acid. Only a few samples were analysed, however, and this limits the conclusions that may be safely made. The replicate data from the River Ecclesbourne also provide information on filtrable metals. (Tables 5.5 to 5.9). Te and Pb show results that are significantly different between the filter types. The concentrations are greater in the GF/C filtered water; 67 jig/l Fe and 6.8 ;ug/l Pb compared with 18 jig/l Fe and 4.3 jig/l Pb in the membrane filtered water. These results reflect the difference between the pore sizes of the filters. Pb and Fe are almost exclusively associated with the particulate phase in these samples (approximately 98% of the total Fe and total Pb). Thus the effect of the larger pore size in allowing the passage of fine material, containing these elements, into the filtrate is well illustrated. The work of Kennedy and Zellweger (1974), which compares the effects of filters of 2 jim (glass fibre), 0.45 jam and 0.1 >im (membrane) pore size on the analysis of filtrable metals (notably Fe, Mn A1 and Ti) parallels these results. Total exchangeable metal values determined by the two filtration methods agree closely, Table 5.8. The results of the acid digestion, however. -193 - Table 5.5 Filtrable Metal Concentrations in River Ecclesbourne Samples Cu Pb Zn Cd Fe Mn Mean 3.0 4.5 95 1.5 18.3 76 Membrane S .D. 0.4 1.0 11.4 0.2 3.1 12 Filtered C.V. (%) 12 15 16 (pg/1) 14 22 17 n. 6 6 6 6 6 16 Cu Pb Zh Cd Fe Mn Mean 3.2 6.8 93 1.6 68 70 GF/C S .D. 0.2 0.7 5.6 0.2 7.5 5.5 Filtered C.V. 8 (pg/1) 6 10 6 13 11 n. 6 6 6 6 6 6 Table 5.6 Results of "t"-test Comparing Filtrable Metal Data (Table 5.4) Element Value of "t" Significance Cu -1.17 N.S. Pb -6.32 P 0.01 Zn 0.41 N.S. Cd -1.23 N.S. Fe -3.38 P 0.02 Mn 1.30 N.S. N.S. = no significant difference. Where results do differ significantly, probability value is quoted. -194 - Table 5.7 Particulate Metal Concentrations in River Ecclesbourne Samples Cu Pb Zn Cd Fe Mn Mean i n 183 111 2.7 993 75 per S.D. 0.4 11 5.5 0.2 65 4.3 volume ipg/1) C.V.(%) 7- 6 5 8 7 6 n. . 6 6 6 4 6 6 wtfacfc Mean 91 3045 1849 .45 16542 1252 32.2 dry S.D. 6.6 215 43 3.9 719 53 4.0 weight C.V.(%) 7 7 2 9 4 4 12 (pg/g) n. 6 6 6 4 6 6 6 Table 5.8 Total Exchangeable Metal Concentrations in River Ecclesbourne Samples Cu Pb Zn Cd Fe Mn A Mean 8.5 187 206 4.2 1012 151 Filtrable + S .D. 0.8 11.6 11.6 0.3 66 11 leached particulate c.v.(%) 9 6 6 6 7 7 ipg/1) n. 6 6 6 6 6 6 B Mean 8.2 178 229 3.1 1073 155 By acidific- S.D. 0. 2 13 12 0.2 44 8 ation prior to f iltration av.(%) 2 7 5 7 4 5 Oig/i) n. 4 4 4 4 4 4 c Mean 13.1 205 246 4.5 2292 150 Total diges- S .D. 1.3 24 8 0.3 113 7 tion of sample C.V.(%) (Total metals) 10 12 3 7 5 5 ipg/D n. 6 6 6 6 6 6 I Results of t-tests Comparing Data in Table 5.7 (A, B and C) C-J3 cr M fD v£> Combination Cu Pb Zn Cd Fe Mn A-B N.S. N.S. N.S. N.S. N.S. .N.S. VO A-C p<0.001 N.S. N.S. p<0.001 p<0.001 N.S. en I B-C p<0.001 N.S. p<0.01 p <0.05 p CO. 001 N.S. N.S. = no significant difference. Values of P are quoted for results that differ significantly. -196 - Table 5.10 Total Exchangeable Metal Concentrations in Duplicate Samples 5.10A Results from Acidification Prior to GF/C Filtration Sample No.* Cu Pb Zn Cd Fe Mn 08/78/3IT 5.0 113 2325 22.7 130 41 08/78/327T 4.0 15 25 1.2 450 60 06/78/28T 5.0 36 462 5.3 170 31 10/78/10T 4.0 19 450 3.1 170 48 08/78/126T 3.0 18 148 2.0 240 74 06/78/3IT 4.5 138 1495 16.6 180 85 08/78/10T 2.5 25 674 4.4 170 52 10/78/28T 3.0 25 1086 10.9 140 38 10/78/352T 4.0 25 81 2.0 680 205 08/78/336T 3.0 30 26 2.5 520 58 06/7 8/126T 2.5 15 128 2.0 440 90 04/78/31T 7.5 313 1550 16.8 550 113 08/78/318T 8.0 28 117 1.8 500 160 10/78/3IT 2.5 90 2480 21.8 140 90 04/78/126T 2.0 18 180 1.8 390 85 10/78/126T 2.0 21 170 2.2 210 - 04/78/10T 14.0 400 1460 12.5 1495 263 Units = pg/l - = missing result -197 - Table 5.10 Total Exchangeable Metal Concentrations in Duplicate Samples 5.10B Results from Sartorius Filtration and 0.5M HC1 leach Sample No. ' Cu Pb Zn Cd Fe Mn 08/78/31 4.4 89 2003 17.9 158 44 08/78/327 3.4 13 14 - 425 50 06/78/28 4.2 39 736 8.9 140 30 10/78/10 3.7 27 783 6.1 126 42 08/78/126 3.0 17 151 1.6 225 69 06/78/31 4.3 124 1455 16.5 127 75 08/78/10 2.9 16 605 3.9 144 45 10/78/28 2.8 23 1050 11.3 98 36 10/78/352 4.2 36 114 1.5 610 163 08/78/336 4.5 38 26 1.1 538 58 06/78/126 3.0 13 119 1.5 209 68 04/78/31 6.9 264 1493 17.7 491 112 08/78/318 8.0 21 62 2.1 428 114 10/78/31 3.3 83 2146 23.6 138 89 04/78/126 3.0 10 150 1.5 229 72 10/78/126 2.4 15 162 1.1 150 23 04/78/10 11.4 314 1220 11.1 1550 200 Units = ^g/l - = missing result -198 - Table 5.10 Total Exchangeable Metal Concentrations in Duplicate Samples 5.IPC . Results of Paired "f'-test Comparing Table 5.10A with Table 5.10B Element Value of "t" Significance Cu 0.295 N.S. Pb 1.906 N.S. Zn 0.817 N.S. Cd 0.157 N.S. Fe 2.835 P 0.02 Mn 2.915 P 0.02 N.S. = no significant difference -199- are generally higher than those for the other methods, as would be expected; c.f. Table 5.8C with Tables 5.8A and 5.8B. Pb and Mn do not differ significantly for the three methods, mean concen- trations for Pb being 190 Mg/l f 178 pg/l, 205 ,pg/l; for Mn 149 pg/l, 155 yg/1 and 150 >ig/l for the three methods respectively. It would appear from this that Mn, and to a lesser extent Pb, are readily available to the lower strength acids, suggesting that they occur as non-residual metals. Practically, the digestion technique is very slow even with small volumes of water. Extreme care has to be taken in avoiding contamination during the evaporation stage from airborne particulates. The data from the experiment comparing the two methods for total exchangeable metals using seven- teen duplicate samples are given in Table 5.10. No significant differences between the results occur except for Fe and Mn. This feature is not easily explained, especially in the light of the data presented in Table 5.8. Apart from the acid strength, the two methods also differ in the length of leaching time. It is possible that longer exposure to acid conditions causes slow release of Fe and Mn from the more resistant oxide phases and silicates in the particulate which does not occur during a shorter leach period. This suggests, perhaps, that time rather than acid strength is a more -200 - important factor controlling the extent of metal release by partial extraction techniques such as these. The reproducibility, as expressed by the coefficient of variation (C.V.), of the results for the filtrable metals using GF/C filters is better than for the membranes. This is surprising in view of the more specific separation between filtrable and non-filtrable metals which is achieved using the membranes. The Pb data for the membranes contain two results which differ by +55% and -17% from the remainder. If these are removed and the statistics re-calculated, then the Pb mean = 4.2 pg/l, S.D. = 0.35, C.V. = 8.3%. A similar situation exists with Fe where two outlying results, 47% and 30% greater than any of the others, contribute to the majority of the variation expressed by the statistics. Re- calculation, removing these results, gives mean Fe = 16.3 jug/1, S.D. = 0.43 and C.V. = 2.6%. The data for the other elements are, however, uniformly scattered about their respective means with no spurious values. The precisions for the particulate determinations (Table 5.7) and the total exchangeable metals (Tables 5.8A and B) are good, with C.V.'s of the same order of magnitude. The precisions for the Pb and Cu data for the total digestion method are poorer, however. Again the major contribution to -201 - the high C.V. for Pb comes from two results which differ from the others by about +20% and -20%. If these are removed, and the statistics recalculated, then the Pb mean becomes 203 ;ug/l, S.D. =4.3 and C.V. = 2.1%. The Cu results are, in contrast, uniformly scattered about the mean. 5.5 Conclusions Filtration of water samples through Sartorius membrane filters and extraction of heavy metals from the particulate by an acid leach, provides a method of analysis which is rapid and requires the minimum of sample handling. Reproducible results for the particulate analyses are obtained, with C.V.'s of less than 10%. There are few contamination problems and the weights of particulate can easily be obtained. Agreement between the two methods for total exchangeable metals is good, allowing comparison of the results. GF/C filters are probably unsuitable for water analysis due to their large pore size. This allows the passage of fine particulates, containing metals, into the filtrate and this clearly affects the analysis of the latter. Results obtained for Pb and Fe are particularly susceptible to error in this case, and this must be considered when comparisons are made between data from GF/C and membrane filtered water. Membrane filters of 0.45 ^m pore -202 - size also allow very fine particulate material to pass into the filtrate, (Kennedy and Zellweger 1974). A filter with a pore size of the order of 0.1 - 0.2 pm is required to separate truly dissolved species from colloidal suspensions (Harding and Whitton 1978 and Kennedy and Zellweger 1974). / -203 - CHAPTER 6 EXPERIMENTAL PROCEDURES 6.1 Seasonal Stream Sediment and Water Sampling Programme An interval of _two months was chosen for the sampling programme designed to cover seasonal variations in metal concentrations in waters and sediments. This interval was considered sufficient to detect seasonal patterns, whilst also allowing time for samples to be processed and analysed between collections. Samples of stream sediment and water were collected from Minsterley Brook and the River Ecclesbourne from December 1977 to' October 1978 inclusive. The collection months have been given the following notation: December 1977 12/77 February 1978 02/78 April 1978 04/78 ... • . . • . . October 1978 10/78 Sample collections were made on the same day of each month whenever possible, or within two days either side. 6.1.1 Sample Collection and Pretreatment All sediment samples were collected by hand, dried at 105 C and sieved to -200 ^im following the procedures described in Chapter 4. Sample sites were chosen so as to be easily recognizable during repeated visits. -204 - The procedures for the collection and storage of water samples and the preparation of sample bottles have already been described (Chapter 4). To reduce the losses of heavy metals by adsorption onto container walls, bottles were conditioned in the following manner. At the site the sample bottle was rinsed with river water and then filled and allowed to stand for five minutes. This water was then discarded and the sample taken. This procedure has been shown to reduce adsorption losses considerably (Nlirmberg et al 1976) . It is thought that available metal binding sites on the bottle walls are rapidly occupied by major ions during the conditioning process. These sites may be reactivated during acid washing of the bottles between sampling occasions. On return to the laboratory exactly one litre of each sample was taken and vacuum filtered through Sartorius membrane filters, (cellulose nitrate, 0.45 ^pm pore size, 47 mm diameter). The filters were prewashed in 10% v/v HNOg and rinsed with DIW before being dried and weighed. Dry filters were moistened with DIW to prevent creasing when the vacuum was applied. Samples were filtered into Buchner flasks containing 5 ml of concentrated HNO^, giving a final sample pH^2. The sample bottle was rinsed with a small volume of DIW to remove stray particulates and the filtered sample returned to it. Filters were dried and weighed and stored in plastic petri dishes pending -205 - analysis. All glassware was silanised (coated with trimethylsilane) to reduce adsorption losses of metals, 6.1.2 Chemical Analysis of Seasonal Samples All sediments were digested using the nitric acid attack described in Appendix I. The method was modified slightly for samples "not analysed the day following the attack. In these instances, solutions were decanted into clean tubes and covered with clear plastic film for storage. This prevented continued leaching of the sediment by the dilute acid solution above it. Samples collected on the following occasions were also leached using cold 0.5M HC1; Hinsterley Brook: 12/77, 02/78, 06/78, 10/78; River Ecclesbournei 06/78 and 08/78. This particular leach was chosen following the work reported by Agemian and Chau (1976), Malo (1977) and Thorne (1978). It is claimed to yield the non-residual phase of the metals in the sediments. The method used was that described by Agemian and Chau (1976) except thats i) lg of sediment (-200 ,pm) to 20 ml of acid was used ii) a leaching time of four hours was found sufficient to extract all the available heavy metals (Vernon pers comm 1978). Extra acid was added to highly calcareous sediments ( >10% w/w Ca) in 2 ml aliquots to overcome the neutralising effects of the carbonate, and to give a final solution pH of -206 - less than two. The details of the method are given in Appendix I. The concentrations of the metals Cu, Pb, Zn, Cd, Fe, Mn, Ca and Mg were determined following each attack using a Perkin-Elmer model 403 flame AAS. Ca and Mg determinations were made on 2 ml aliquots of sample solution diluted in the ratio of 1:1 with 0.5% v/v LaCl^ solution to over- come interference effects. Details of operating conditions for the instrument are given in Chapter 4. Water samples were analysed by flame AAS for the suite of heavy metals listed above following solvent-extraction as described previously (Appendix I). Ca and Mg were determined on 2 ml aliquots of water diluted 1:1 with 0.5% LaCl3 solution. The pH of water samples was determined within a few hours of collection using a Pye Unicam model 293 pH meter. Particulate material was analysed for heavy metals following the leaching procedure described in Chapter 5 using cold dilute HC1. Estimates of the efficiency of the solvent- extraction method and its precision were made on samples of DIW to which known concentrations of heavy metals had been added. Additional data on precision were obtained from analyses of replicate water samples. Reagent and glassware contamination was checked by the analysis of control samples of DIW and acid washed filters. -207 - 6.1.3 Assessment of Sampling and Analytical Variation in Seasonal Sediment Data In any experiment designed to investigate the seasonal variation of a particular parameter, it is important to estimate the variations due to the analytical and sampling errors inherent in the results. Therefore, five bulk samples of sediment were taken from each of the following sitest 031 and 126 on Minsterley Brook and 328 and 351 on the River Ecclesbourne. These represented contaminated and background sites respectively from the two rivers. Each bulk sample was dried and sieved to -2 mm, carefully homogenised and split into five sub- samples using a sample splitter. Each sub-sample was then sieved to -200 ^m. Separate aliquots were taken and analysed following the nitric attack procedure described earlier. This design thus gives an estimate of sampling error from the bulk samples and analytical error from the sub-samples. The two sources of error can be compared using a one-way analysis of variance (ANOVA). Estimates of analytical precision were also made by replicate analyses of a standard stream sediment throughout the analytical programme. 6.2 Partitioning of Heavy Metals within Stream Sediments Heavy metals may be partitioned within a sediment either chemically or physically. The -208 - former was investigated following the simple distribution between residual and non-residual phases (Agemian and Chau 1976). The distribution of non-residual heavy metals was also examined in relation to the grain-size of the sediments. This part of the work was restricted to samples collected on one occasion each from Mins'terley Brook (10/78) and the River Ecclesbourne (06/78). 6.2.1 Determination of Residual and Non-residual Heavy Metals in Sediments The seasonal sediment samples were used for this investigation i.e. oven dried at 105°C and sieved to -200 ^m. Non-residual heavy metals were determined using the 0.5M HC1 acid leach described above. The total heavy metal concentration was determined using a nitric acid-perchloric acid attack (see Appendix I). Although some resistant silicate minerals are not digested by this attack, it gives a result which is a close approximation to the total heavy metal content of the sediment (Agemian and Chau 1976). The residual portion of the heavy metals is thus equal to t total metal - non-residual metals. 6.2.2 Size Fractionation of Stream Sediments Five bulk samples of sediment were taken from each river. The sites were chosen so as to represent -209 - the dispersion pattern of heavy metals in each river. The sites were: River Ecclesbourne Minsterley Brook 352 33 328 31 336 28 325 10 321 03 The sediment samples were split into the following six fractions belonging to the Wentworth class- ification of particle sizes. Particle Size (jam) Name -2000 +1000 Very Coarse Sand -1000 +500 Coarse Sand -500 +250 Medium Sand -250 +125 Fine Sand -125 +61 Very Fine Sand -61 Silt A stack of five Perspex sieves holding 1000 um, 500 jam, 250 ^pm, 125 pm, and 61 ^m nylon bolting cloth respectively was assembled using PVC insulating tape. The coarsest sieve was placed at the top of the stack and a Perspex lid and base were used to retain the sample. Samples were oven dried at 105°C, very lightly disaggregated in a pestle and mortar and manually sieved to -2000 Jim. The weighed sample was placed in the top sieve of the assembled stack and the lid secured. The stack was placed on a mechanical sieve shaker -210 - and shaken for two periods of 30 minutes. The individual fractions were carefully removed, weighed and placed in paper bags. The sieves were cleaned between each sample using dilute HNO^, followed by rinsing with DIW and drying. Unground portions (lg) of each fraction were leached with cold 0.5M HC1 following the method'given in Appendix I. 6.3 Measurement of River Discharge Discharge data for the River Ecclesbourne and Rea Brook were provided by the Severn-Trent Water Authority from permanent weirs. Discharge was also measured at several sample sites on the following occasions in Minsterley Brook; 04/78, 06/78, 10/78. Measurements were made using a hand held current meter (Ott model CI, coupled to a 12-001 Battery operated Revolution Counter). Flow measurements were made as close to sample sites as the following criteria allowed; i) straight reach of water with parallel velocity threads - avoiding bends, ii) Stable stream bed free of large rocks, weeds and other obstructions likely to cause turbulence, iii) A flat stream bed profile to eliminate vertical velocity components. Measurement at the upstream edge of riffles was avoided. The method of measurement used is given in detail by Bidewell (1971) and will not be repeated here. The principal however, is to divide the given -211 - FIGURE 6.1 Stream Discharge Measurement by Partial Area Method EXPLANATION 1,2,3, n Observation points bl,b2,b3,...bn Distance, (m), from initial point to observation point dl,d2,d3...,dn Depth of water, (m), at observation point ______Boundary of partial area imi) -212 - section of stream into a number of partial areas, the exact number being determined by stream width and flow pattern. A current measurement is then the summation of the products of the partial areas and their respective average velocities. The total discharge for the stream at that point is represented by the formula: n Q = (a.v.) where i Q = total discharge l ii a individual partial i " area cross-sections v. = corresponding mean 1 velocity of the flow normal to the partial area All current meter measurements were made by the midstream method. This method assumes that the average velocity at each vertical location represents the mean velocity in a partial rectangular area. This area extends from half the distance from the preceding meter location to half the distance to the next meter location, and vertically, from the water surface to the stream bottom. See Figure 6.1. The meter was set to 0.6 of the depth of the stream at each meter location, as recommended by Bidwell (1971). Depths were measured using a graduated staff, and the section widths were read from a nylon tape stretched across the stream. The flow velocity at each point is determined from the formula: -213 - v = r x c where t v = velocity t r e number of revolutions of the meter propeller c « constant for the propeller, determined experimentally t = time in seconds 6.4 The Determination of Heavy Metals in soils, Alluvium and Mine Waste 6.4.1 Sample Collection An estimate was made of the areal extent of the heavy metal contamination in the Minsterley catchment by a series of soil samples taken along three transects across the valley (Fig.6.2). Samples were taken at depths of 0-15 cm and 30-45 cm using a 25 mm screw auger. Five subsamples were collected from each site and bulked in the field for sieving and analysis. Samples were collected in Kraft paper envelopes and oven dried at 105°C. When dry, the samples were disaggregated with a pestle and mortar and passed through a 2000 ^pm nylon sieve to remove stones. Material less than 2000 />im was collected and ground to pass a 200 jam sieve. Samples of alluvium were collected at river sample sites from both banks to estimate the potential input of metals to the river system by bank erosion and surface run-off. Surface samples were collected (0-15 cm) using a soil auger or stainless steel -214 - N A FIGURE 6.2 Soil sampling transects across Minsterley catchment KEY • Lead mine Soil sample site Built-up area -215 - trowel for unconsolidated material. Three to five subsamples were taken at each site and bulked as before. Sample treatment was as for the soils. Samples of mine waste were collected from the dump at Gravels, on a grid from depths of 0-15 cm and 30 cm using an auger or trowel. (See Fig 3.3). Samples were dried at 105°C and sieved through a 200 ^m sieve without grinding. A deeper profile was collected using a 75 mm diameter Jarret auger whilst boring a hole to collect shallow groundwater beneath the dump. Samples were taken from 1.0 m, 1.5m, 2.0 m, and 3.0 m. Hand specimens of Galena, Sphalerite and Chalcopyrite were collected from the dump. These were crushed in a jaw crusher to 1 cm and the pieces hand picked to separate pure ore samples from those associated with gangue minerals and wall-rock. The pure ore samples were further ground in an agate pestle and mortar to -190 +110 jam. This fraction was further purified by heavy liquid separation using tetra-bromo ethane. 6.4.2 Chemical Analysis All samples of soil, bank material and mine waste were analysed for Cu, Pb, Zn, Cd, Fe, Mn, Ca and Mg by flame AAS following a nitric acid attack. (Appendix 1). Three replicate samples of each ore -216 - mineral were analysed for heavy metals following a nitric-perchloric acid attack (Appendix 1). 6.5 Determination of Heavy Metals in Shallow Groundwater and Mine Drainage Samples of drainage water were collected from accessible mine adits draining"into the Minsterley catchment (see Fig 3.1). Those entering the Ecclesbourne at Wirksworth were not located. Samples were taken with regular seasonal samples from the adit at Cliffdale Mill, two occasions each from Wood Level and Boat Level (08/78 and 10/78) and once from Gate Level (10/78). Water samples were also collected from small seepages at the base of the dump at Gravels, at the junction of the dump with underlying Hope Shales, in October 1978. A hole was drilled through the dump using a 75 mm auger to the zone of shattered shale and clay. This was left overnight to fill and two samples of water collected using a glass bottle weighted with glass beads and lowered into the hole. Care was taken not to dislodge material from the sides of the hole during the raising and lowering of the bottle. Samples were transferred to one litre polythene bottles at the surface. Water samples were filtered and analysed following the procedures described earlier. ' -217- CHAPTER 7 ANALYTICAL RESULTS AND DISCUSSION FOR MINSTERLEY BROOK AND THE RIVER ECCLESBOURNE 7.1 Introduction This chapter describes and discusses the results obtained from the more detailed investigations on Minsterley Brook and the River Ecclesbourne out- lined in Chapter 6. These results have been summ- arised where possible to avoid including large numbers of data in the text. Statistical summaries of the seasonal data and data for replicate analyses are included in Appendix 4. These tables are ref- erred to in the text by using *A4f to prefix the table number. The complete data listings are given in Appendix 5. Units used in tables of results are summarised below: i) Solid Materials, e.g. stream sediments, soils. All values for chemical analyses are given as ppm (parts per million) dry weight = pg/g dry weight. Occasionally results for Fe and Ca are quoted as 4 % where 1% dry weight = 10 ppm. ii) Water Analyses. Trace metal analyses are quoted as ppb (parts per -218 - billion) equivalent to Jig/l. Values for Ca and Mg are quoted in ppm. pH is quoted in pH units. Fil- trable metal concentrations are denoted by (F) and total exchangeable metals by (T). N.D. signifies that values were not detected - i.e. below detection limit for the element of interest. iii) Statistical Notation The number of samples taken to give a mean value are denoted by N = no. of samples, S.D. denotes standard deviation (CT2) and C.V. denotes the co- efficient of variation. This term is defined as, S.D./Mean x 100%. Where 't' or • f* tests have been performed, significant differences are indicated by quoting the value of the probability p at which the test proved significant, e.g. p = 0.001. N.S. denotes non-significant result. Sampling occasions are referred to by the not- ation 02/78, 04/78 giving the month and year, i.e. February 1978, April 1978. Left hand and right hand river banks are referred to facing upstream. 7.2 Heavy Metals in Alluvium, Mine Waste, Soils and Effluents 7.2.1.Minsterley Brook The results of analyses of the mine waste samples from Gravels mine are presented as a mean value for -219 - the twelve samples in Table 7.1. Although there is considerable variation in the data, the exercise was not intended to give a detailed breakdown of variation in metal distribution within the dump but rather to obtain an overall realistic estimate of the levels of heavy metals present. The sample sites and that of the borehole are shown in Figure 3.3. The data for the borehole (surface to 3.0 m) are shown in Table 7.2, with the distributions for Pb, Zn, Cd, and Fe shown diagrammatically in Figure 7.1. A visual description of the profile is also given. Table 7.3 gives the results of analyses of samples of galena, sphalerite and chalcopyrite collected from the dump; the results are the means of three replicate analyses. Results for dump drainage and groundwater are given in Table 7.4. Four drainage levels in the catchment were located and identified during the study. These weres Wood Level, Gate Level, Boat Level and Snailbeach Level (see Figure 3.1). Effluent ana- lyses are given in Table 7.5; the values for Snailbeach are a mean over six sampling occasions. The results for site 124 (see Figure 3.1) are also given as these indicate the levels of metals enter- ing Minsterley Brook from Boat Level. Concentrations of metals in soils 0-15 cms and 30 - 45 cms depth are'given in Table A4.1. Levels of Pb and Cd in bank alluvial soils are -220 - Table 7.1 Mean Concentrations of Metals in Mine Waste from Gravels Dump Cu Pb(%) Zn(%) Cd Fe Mn Ca(%) Mg Mean 419 2.27 1.86 154 6883 6800 29.64 298 S.D. 111 0.91 0.82 60 1117 482 2.23 45 C.V.(%) 27 39.9 44.2 39 16 7.1 7.5 15 Units s ppnr No. of samples = 12 Sample depth 15cm Table 7.2 Chemical Data for Mine Dump Borehole Sample depth Code Cu Pb Zn Cd Fe Mn "»> Mg PH (m) DPI 278 15000 13220 122 6400 6320 27 284 7.1 0 DP2 168 19400 7680 69 6000 6200 27 268 7.0 1.0 DP3 206 22000 8120 71 25000 2960 10 1500 6.9 1.6 DP4 44 6400 7400 36 20600 180 1.43 1200 6.5 2.2 DP5 56 1740 2120 13 47000 240 1.23 2285 6.5 2.8 DP6 48 760 522 5 37200 360 1.65 — 6.4 3.2 Units : ppm Table 7.3 Heavy Metal Content of Ore Samples from Gravels Mine Ore Cu Pb Zn Cd Fe Mn ZnS 1460 553 647000 4230 19800 N.D. PbS 4 70300 103 4.3 173 N.D. Cu-FeS 367000 427 6070 39 316700 N.D. Units s ppm N.D. = not detected Mean of 3 replicates -221 - Mine waste > Fragments of shale calcite & ore ( Black organic rich clay Grey-green clay Grey-green clay + shale fragments (<5mm) + orange Fe-hydroxide streaks Khaki-brown clay • 1cm shale fragments Zn Pb Fe log metal concentration 10 Figure 7.1 Description of Dump Borehole at Gravels Mine and Profiles for Pb, Zn, Cd and Fe. -222 - Table 7>4 Chemical Data for Mine Dump Drainage and Groundwater Cu Pb Zn Cd Fe Mn Ca Mg pH Ground Water (F) 2.3 557 9500 19.8 833 1500 240 14.6 6.5 Drainage Water (F) 2.5 200 32185 445 85 250 160 5.0 6.8 Units t heavy metals ppb t Ca & Mg ppm Table 7.5 Concentrations of Metals in Drainage Adit Effluents Wood Level Cu Pb Zn Cd Fe Mn Ca Mg pH 08/78 (F) 2.7 7.5 800 6.1 43 25 54 5.2 7.2 10/78 (F) 2.5 3.8 805 6.2 22 32 56 5.6 7.0 08/78 (T) . 4.9 11.5 808 6.3 76 33 - - — 10/78 (T) 3.9 6.3 808 6.4 68 35 - - - Boat Level Cu > Pb Zn Cd Fe Mn Ca Mg pH 08/78 (F) 0.2 9.0 5250 21.5 140 110 52 4.4 6.8 10/78 (F) 1.0 7.5 5195 23.5 140 110 54 4.6 6.7 08/78 (T) 0.4 14.0 5260 21.7 230 110 10/78 (T) 1.2 12.5 5210 23.6 260 111 Gate Level Cu Pb Zn Cd Fe Mn Ca Mg pH 10/78 (F) 0.5 6.3 120 1.0 29 49 54 6.2 l.l 10/78 (T) 0.6 11.3 132 1.3 73 67 Snailbeach Level (F) Cu Pb Zn Cd Fe Mn Ca Mg pH Mean 1.05 95 678 5.6 17 30 66 8.1 7. S.D. 0.17 15.3 57 0.2 84 11.4 6.4 2.3 0.. C.V. (%) 16.2 16.1 8.4 4.1 49.5 38.1 9.7 28.5 l.< N = 6 -223 - (Table 7.5 contd.) Snailbeach Level (T) Cu Pb Zn Cd Fe Mn Mean 1.4 106 682 5.9 26.4 34 S.D. 0.23 19.2 63.7 0.38 10.6 11. C.V. (%) 16.4 18.1 9.3 6.4 40 34. N = 6 Site 124 Cu Pb Zn Cd Fe Mn Ca Mg pH 08/78 (F) 1.0 14.0 1600 6.5 80 40 32 4.2 7.e 10/78 (F) 1.0 8.8 2520 9.8 42 55 34 7.6 7.5 08/78 (T) 1.2 25.0 1640 6.9 122 48 10/78 (T) 1.2 14.8 2580 10.5 77 64 Units t heavy metals ppb N = number of samples : Ca & Mg ppm - = no analysis performed Table 7.6 Concentrations of Metals in Shale Samples from Minste'rley Brook Cu Pb Zn Cd Fe • Mn Ca Mg (%) 29/R 21 76 82 0.8 3.60 60 1680 3680 31/R 24 20 124 1.2 4.00 112 1000 6080 32/R 27 20 78 1.2 2.96 56 320 4400 S 50 20 100 0.2 850 S = 1 Typical Shale* after Levinson (1974) Units = ppm = no data given -224 - shown as profiles down the river in Figures 7.3 and 7.4. The complete data are tabulated in Table A4.2. Tributary bank soils are shown in Table A4.3. Three "grab" samples of weathered shale out- cropping in the river bank were also taken and ana- lysed. The analyses of these are shown in Table 7.6. These samples were collected from the upper part of the Minsterley catchment and are dark grey to black rusty weathering shales. They are very fine grained and non-micaceous, belonging to the Hope Shales group. The site numbers correspond to stream sample points (see Figure 3.1). Concentrations of Pb and Zn in the mine dump are high, as would be expected; the concentration of Ca is similarly high. Iron levels are lower than would be anticipated considering the concen- trations present in the sphalerite, chalcopyrite, and Hope shale. It would seem that Fe must be quite mobile, being rapidly leached and removed by percolating rainfall, despite the high pH in the surface layers of the dump. (c. 7.0). The borehole drilled through the dump indicates that there is some 1.5 m of waste material above the original ground level, marked by the organic rich reduced layer. Below this a metre of grey- green clay occurs indicating a reducing environment and this passes sharply into brown clay with shale fragments ~ a form of C horizon. The distribution -225 - of Fe and Mg reflect the differences in these horizons veil, with a sharp increase in concentration of both elements in the organic layer. The leached horizon below this then shows depletion in these elements, with a second enrichment occurring above the bottom layer of clay with shale fragments. Cu, Pb, and Zn all show a degree of enrichment in the organic horizon and depletion in the clays below. Cd, however, shows a steady decrease with depth. Ca and Mn exhibit the most marked differences in dis- tribution between the dump and the underlying clay. In both cases the organic horizon contains inter- mediate concentrations of these elements. The organic zone appears to act as a buffer preventing the movement of Cu, Pb, and Zn out of the dump into the underlying clay. This could be achieved by complexation with organic materials or secondary sulphide mineral deposition. This material had a very sulphurous odour to it. The impervious nature of the clay also causes water percolating through the dump to run across the interface between the waste and the clay. This form of water movement was observed and sampled in the river bank adjacent to site 33 (Seepage sample). This sample contains very high concentrations of Zn and Cd; three to four times the Zn and over twenty times the Cd concentration of the dump groundwater sample, sug- gesting that leaching of metals by circulating water does occur despite the high pH values. -226 - Boat Level is the largest contributor of heavy metals amongst the various drainage adits entering the Minsterley Brook catchment. The levels of Zn (F) and Cd (F) are still high at site 124 which is about 1.5 km downstream from the entrance to the level. The level drains the Bog and Tankerville mines which were primarily Zn "producers. Although the adits are potential sources of heavy metals to the drainage system, the flows at Gate Level and Snailbeach Level are very low when compared with the flow in the river which they join. Wood Level contains a larger volume of water, though again it is doubtful whether it supplies a very significant amount of water to the main river chan- nel except during times of low base flow. At this time the levels would become important contributors to the heavy metal load of the stream, particularly as they tend to maintain fairly constant flows of water even during times of drought. For example, Wood Level continued to flow during the 1976 drought period when flow in the river itself at this point had virtually ceased (information supplied by local farmer). During the period of this study Snail- beach level maintained a fairly constant flow inde- pendent of weather conditions and the state of the main stream. The potential impact of Boat Level upon the mainstream is clearly much larger, as it is part of the source flow for the tributary enter- ing Minsterley Brook at site 124. A significant -227 - local problem is the apparent use of the stream near the level entrance for watering livestock. The particulate load for the drainage levels is generally small and the majority, that is betw- een 6"0 to 100% of the heavy metals are in the fil- trable phase for all the adits. This is significant when metal concentrations are compared with WHO Highest Desirable Limits (HDL), and EEC recommended limits (Tables 1.3 and 1.4). In all cases except Gate Level, the EEC limits for Cd in water intended for drinking water abstraction are exceeded (Table 1.3). At Boat Level, the Cd concentration (=^=22 ppb) is over four times the irrigation water limit of the FWPCA (5 ppb),(Table 1.5). Levels of Zn ( > 5000 ppb) and Fe (140 ppb) at the entrance to this level also exceed the WHO HDLs (Zn; 5000 ppb, Fe; 100 ppb) . Clearly drainage from metal mines of this type would be considered unsuitable as a water source simply on the grounds of its origin. The impact of this drainage on surface water quality is considerable, and is clearly illustrated by the filtrable Cd levels (7-10 ppb) at site 124, which still exceed the FWPCA limits for irrigation waters. The results for the mineral analyses corres- pond well with theoretical mineral compositions for zinc blende and chalcopyrite. Pure zinc blende (ZnS) should contain 67% Zn, and pure chalcopyrite (CuFeS_) 34.63% Cu and 30.43% Fe (Table 7.3). Thus -228 - the efficiency of the analytical method at these high concentrations of metals is confirmed. The digests of the galena samples all contained a white insoluble precipitate. This was probably lead sulphate formed by oxidation of the sulphide by the nitric and perchloric acids. Consequently the results for this analysis are lower, at least for Pb, than would be expected from the mineral species present. The three soil transects across the Minsterley Brook valley all illustrate the historic effect of metal contamination of alluvial soils adjacent to the river (see Figures 7.2A and 7.2B). This point is clearly made when the average abundances given by Levinson (1974) (see below) for trace elements in soils are considered alongside the present results in Table A4.1. Average Abundance in Soils, after Levinson (1974). Cu Pb Zn Cd Mn Units ; ppm 2-100 2-200 10-300 1.0 850 Transect A also has elevated levels of Zn at site A8 which is near an old mineral railway line. Traverse C shows the obvious marked effect of the mining and mineralisation on soil heavy metal con- centrations (Figure 7.2B). The effect is quite restricted, however; site C3 is less than 200 m from the mine dump and site C6 is about 500 m away, -229- 1000 ppm Pb 5 00 A1 A2 A3 A5 A6 A7 A8 A9 Brook 15600 600 ppm Pb 200 30-£5cm B1 B2 B3 B4 JB5 B6 B7 B8 Brook 0 1km Ficure 7. 2A Pb in Soils of the Kinsterley Catchment - Transect A and B. Figure 7.2B Pb in Soils of the Minsterley Catchment - Transect C. -231 - but at the top of a hill overlooking the mine. Metal levels become elevated again in the vicinity of the Pennerley mines (sites CIO and C12). The source of the metals at site C3 is probably wind blown dust as the underlying rocks probably con- tain no mineralisation (see Section 3.1.2). The site is also elevated above the river bed and is unlikely to be affected by flooding or ground- water seepage. Concentrations of Cd, Cu, Pb and Zn in allu- vial soils in Minsterley Brook are elevated and reflect the high levels encountered in the sedi- ments (Table A4.2, Figures 7.3 (Pb) and 7.4 (Cd)). The clearly defined dispersion patterns of the metals down the river from site 33 described by the sediments do not occur in the bank soils. The low levels at site 30, left bank looking upstream, are conspicuous compared with those on the right bank (e.g. 30Ri Cu=228 ppm, Zn=13200 ppm, Cd=88 ppm, /30Lt Cu=81 ppm, Zn=204 ppm, Cd=1.2 ppm). The left bank is steep and contains outcropping shale and thin soil, and no alluvium has been deposited. Shale sampled from this bank has a trace element composition within the limits of a "typical shale" as given by Levinson (1974) (see Table 7.6). The Cd level is somewhat enriched, but the Mn value is low. Site 10 is adjacent to the former Barytes mill (? Pb ore treatment works), and this is re- -232 - -233 - -234 - flected in the high metal levels (lOLi Pb=2.86%, Zn=9080 ppm, Cd=82 ppm). Site 105 on Rea Brook has also been contaminated by this mill, reflected in Pb levels of 3.2% and 2.8% for the left and right banks respectively and Cd levels of 100 ppm and 92 ppm. The calcium concentration in the right bank (17%) is also very high Ccfs site 10L, 12.4%, site 31L, 1.92%) and is thought to be related to dumping of mill waste material. At site 9, the river had been dredged at an earlier date and sediment deposited on the fields adjacent to it (information given by land owner). The contamination is obvious (i.e. 09L, Pb=1.2%, Cd=34 ppm; 09R, Pb=2.4%, Cd=28.4 ppm). The pas- ture grass now growing on the dumped sediment has a distinctive yellow colour. Below site 9 levels decrease towards those at control sites. Two conclusions can be drawn from these results. Firstly the bank soils constitute a source of heavy metals to the water course by means of leaching and physical collapse. A cycle can be envisaged here as sediment deposited on the insides of meander bends becomes incorporated into the alluvial flood plain, whilst material deposited at an earlier date is eroded from the outside of the bend. Secondly, the practice of dredging watercourses to improve flood control and depositing the sediment on ad- jacent farmland can have deleterious effects on -235 - the quality of the land. 7.2.2. River Ecclesbourne Samples of bank alluvial soil were taken from both banks at each river sampling point. Figures 7.5 and 7.6 illustrate the downstream distribution of Zn and Cd in these soils. -The data for all the elements are given in Table A4.4. Levels of metals in tributary bank soils are shown in Table A4.5. No samples were taken at site 328 as both banks had standing crops to which access was restricted. Data for the effluent from the Wirksworth water reclamation works are given in Table 7.7. A mean value for four sampling occasions has been given. No mine adits were located in the Eccles- bourne catchment during this study, and soil tran- sect data across the catchment were not obtained. The soils adjacent to sites 318 and 352 con- tain highly anomalous metal concentrations. Down- stream from site 321 to 351 levels of Pb and Zn decline gradually, whilst those for Cu and Cd remain approximately constant on both sides of the river. The effect of the heavy metal input at the headwaters of the river upon the bank soils is still apparent at site 351. Concentrations of Pb, Cu, Zn, and Cd are often more than twice those at un- contaminated control sites (e.g. 351R; Pb=1120 ppm, -236 - Fiqure 7.5 Downstream Distribution of Zn in River Ecclesbourne Bank Soils -237 - o LD OL O Fiaure 7.6 Downstream Distribution of Cd in River Ecclesbourne Bank Soils -238 - Table 7.7 Heavy Metals in Effluent from Wirksworth W.R.W. Filtrable Cu Pb Zn Cd Fe Mn PH Mean 13.4 8.0 83 1.2 75 39 7.2 S.D. 4.5 3.5 21.2 0.3 28.7 30 0.1 Max. 20.4 15.8 108 1.6 113 90 7.3 Min. 9.0 5.0 54 0.7 45 18 6.95 C.V. (%) 33.6 44 26 27.5 38.3 76 1.8 Total Cu Pb Zn Cd Fe Mn Mean 28.1 27.4 138 2.6 205 53.5 S.D. 8.6 3.7 12.4 0.8 25.7 25.7 Max. 38 32.5 155 3.6 245 97 Min. 16 23.0 120 1.7 180 34 C.V. (%) 30 13.4 9.0 29 12.6 48 No. of samples = 4 Units * ppb Samples taken on following occasions I 10/77, 12/77, 04/78, 08/78. -239- Zn=548 ppm, 322R; Pb=560 ppm, Zn=168 ppm, 331R; Pb=440 ppm, Zn=140 ppm). The historic accumulation of heavy metals in the alluvium and its effects on land now used for agriculture is again illustrated. The input of heavy metals by the water rec- lamation works shows some considerable variation over the four samples taken. (See Section 7.4.2.). For the heavy metals, approximately 48% Cu, 29% Pb, 60% Zn, 46% Cd, 37% Fe and 73% Mn are in the fil- trable form. None of the heavy metal concentrations, however, exceed either the WHO HDL's or EEC recom- mended levels for drinking water abstraction. 7.3 Patterns of Metal Dispersion Sediment metal concentrations (nitric attack), filtrable metal and total exchangeable metal con- centrations are considered in this section for the sites sampled regularly during the yearly programme. The data have been condensed into tables giving the mean, standard deviation (S.D.), coefficient of variation (C.V.), and maximum and minimum metal concentrations for each type of sample at each site over the year (Tables A4.6 to A4.13). The data for control sites are also included. The complete data are given in Appendix 5. The summarised results are also visually expressed in Figures 7.7 to 7.18. These show the mean, maximum and minimum metal con- centrations plotted against distance ^oiowsWtavn. \-*o»m. SVOW . -240 - 7.3.1. Metal Dispersion in Sediments in Minsterley Brook Cu, Pb, Zn, Cd Plots of metal concentration against distance yield similarly shaped curves for these four ele- ments (see Figure 7.7). Peak Zn and Cd concentra- tions on the yearly mean plots occur at site 31, whereas those for Cu and Pb occur at the mine site (33) . This pattern is not consistent for Cu and Pb, although it is so for Zn and Cd for all six occasions (see data listing, Appendix 5). The contrast between the peak concentrations at sites 33 and 30 (31 OOOppm Pb, 34 OOOppm Zn, 206ppm Cd) and those at control sites such as 129, 134, 132 and 02 is large. Peak levels for Cu, Pb, Zn and Cd are 50, 103, 23 and 80 times respectively, higher than background values calculated as the means of the yearly means at the four control sites listed above (Cu=21ppm, Pb=300ppm, Zn=380ppm, Cd=2.7ppm). Despite the very high levels at the mine site, sediment concentrations at site 134 are at or very close to levels at the control sites (02, 105, 132). Fe and Mn The pattern of Fe concentration with distance (Figure 7.8) contrasts markedly with elements such as Cu and Pb. The mean level of Fe rises steadily soooo 2000 50000 Lead ppm \T Fig 7.7 1391) 11 10 2ft 107 10 Dispersion Plots for Cu.Pb.Zn and Cd in Sediments - Minsterley Brook -242 - from ^ 1% at the mine site to about 3% at site 28. Between these sites, the sediments take on a brown colour due to iron staining of the grains. This was confirmed by optical examination of thin sections of sediment. Amorphous "iron-oxide" par- tides were also seen, though no chemical analyses were performed. (The sections were cut from samples of sediment impregnated with epoxy resin) . The mean level pf Fe continues at about 3% dropping to about 2.3% at sites 126 and 134. Manganese yields a similar pattern to the other heavy metals, with peak concentrations occurr- ing at site 33, although levels equivalent to those at control sites of the order of 1200 ppm are attai- ned by site 107. / Ca and Mq Levels of Mg increase sharply from lOOOppm at site 33 to 3000ppm at site 28 (Figure 7.8). The levels then continue to rise and plateau at about 3500 ppm in Rea Brook. This pattern appears to reflect a steady input from the soil. Ca follows a similar pattern to the heavy metals and reflects the decrease in the calcite grains visible in the sediment. A deviation in the curve occurs at site 10. This is probably the influence of the high bank soil Ca (12.4% in left bank) which is either a product of the Ba mill or agricultural liming Iron i 129 33 31 30 2t 107 10 9 3 126 111 Fig 7.8 Dispersion Plots for Fe.Mn.Ca and Mg in Sediments - Minsterley Brook -244 - of the soil. 7.3.2. Metal Dispersion in Sediments in the River Ecclesbourne Cu, Pb, Zn, Cd — Levels of Cu, Zn and Cd in contaminated sedi- ments at site 318 are generally lower than those at equivalent "peak" sites on Minsterley Brook (cf mean values for Cux 75ppm vs llOOppm, Znx 2000ppm vs 26-30 OOOppm, Cdi 30ppm vs 200-240ppm for the two rivers respectively) . Mean Pb levels are fairly similar between the two rivers for the highly contaminated sites (cf site 318, mean Pb=700ppm, site 33, 30 OOOppm, site 31, 24 OOOppm, (Figure 7.9)). The ranges in Pb concentrations are very similar (e.g. site 318; 6320-52 OOOppm, site 31; 4360- 68 OOOppm). Mean concentrations at control sites for Cu and Cd tend to be similar (e.g. site 02; Cu~14ppm, site 331; Cu=18ppm, site 02; Cd=1.3ppm, site 331; Cd=2ppm). Levels of Pb and Zn at control sites tend to be higher in the Minsterley Brook catchment (e.g. at site 02; Pb=250ppm, Zn=196ppm, and at site 331 (Ecclesbourne); Pb=75ppm, Zn=91ppm), The reasons for the high levels of Pb at site 318 are not clear. Sites 352, 347 and 315 upstream have sediment Pb concentrations ranging between approximately 1000 to 4000ppm over the year (see Tables A4.12 and A4.13),"suggesting a localised source for Pb contamination around site 318. There 2000. ppm Zinc ppm Ki 1000 3$1318 328 I 2km N) U1 352 31 & 328 321 33S 325 127 3Si I r/ i Codmium ppm Lwd ppm 383 318 328 321 138 32S J27 351 Fig 7.9 Dispersion Plots for Cu, Pb,Zn and Cd in Sediments-R.Ecclesbourne nmi 32a 371 ns JJJ 127 ))1 -246 - is no evidence for mineralisation, mining or mineral processing in the immediate vicinity of the site however, although alluvial soil on the left bank is very high in Pb ( y25000ppm). In addition pieces of slag and pebbles containing traces of galena have been found in the river sediments here. Several farm tracks and a railway embankment come close to or cross the river near this site and at points imm- ediately upstream. The use of smelter slag and mine waste is quite common in the construction of these features and would provide a suitable local source for the Pb contamination. Although site 318 dep- icts a site of extreme local Pb contamination, levels of Cu, Pb, Zn, and Cd at sites 352, 315 and 347 illustrate the high levels of sediment conta- mination due to the mining and mineralisation in the area to the north of the catchment. Mean levels are elevated several times above control concentrations (e.g. site 352; mean Cu=76ppm, Pb=4400ppm, Zn=1950ppm, Cd=26ppm compared with site 331; (control site) mean Cu=18.4ppm, Pb=75ppm, Zn=91ppm, Cd=2.1ppm). Metal concentrations decrease steadily downstream, and approach control values at site 351. Fe and Mn Mean levels of Fe and Mn follow similar di- stributions downstream (Figure 7.10) with minimum values at site 321 (Fe=1.75%, Kn=580ppm), inc- Iron 152 31ft 126 321 336 325 127 1 51 Fig 7.10 Dispersion Plots for Fe.Mn.Ca and Mg in Sediments 152 316 326 3J1 336 325 327 351 River Ecclesbourne -248 - reasing to Fe=2.5% and Mn=1000ppm and remaining approximately at this level for the remaining sites. No explanation can be given for this distribution on the basis of the present data. Levels are si- milar to those at the control site 331. At site 315; mean Fe=5.07%, mean Mn=2616ppm and at site 322; mean Fe=4.11%, and mean'Mn=1347ppm. Pebbles stained with Fe and Mn occur abundantly in the streambeds at both these sites, in contrast to the other sites in the catchment. Ca and Mq Ca and Mg show similar distributions (Figure 7.10), falling steadily in concentration downstream from peak values of c. 10% w/w Ca and c. 3500ppm Mg at site 352. This distribution relates to the decreasing influence of the calcareous rocks in the headwaters of the Ecclesbourne upon the sedi- ment geochemistry. The elevated Mg concentrations at the headwater sites reflect the dolomitic lime- stones that occur north of Wirksworth. The small secondary peak in the mean Mg distribution could relate to the gypsum occurring in the Triassic rocks in the west of the catchment. Levels of Ca at the "peak" sites are approximately 30% of those at site 33 in Minsterley Brook. 7.3.3. Variations in Minsterley Brook Sediment Data The mean metal dispersion plots in Figure 7.7 -249 - for Cu, Pb, Zn and Cd show that the range in con- centration decreases in magnitude away from the mine site. The C.V. values, however, (Table A4.6) do not exhibit any consistent trend, except that they are about 60% for all metals at site 33. The range of values displayed by Fe (Figure 7.8) ex- hibit no definite trend, whilst for Mn, the range remains fairly consistent. Calcium (Figure 7.8), in common with Cu, Pb, Zn, and Cd (Figure 7.7) shows a decrease in concentration range with dis- tance away from Gravels, whereas Mg levels vary by approximately the same amount at each site (Figure 7.8). As can be seen from Tables A4.6 and A4.7 listing maximum and minimum data, the actual differences over the year can be very large (e.g. Zn; site 33: 7000ppm to 46 400ppm, mean=26 433ppm, Cu; site 33: 2480ppm to 256ppm, mean=1103ppm) . Sampling and Analytical Error To interpret seasonal results, the data for the replicate analyses of samples from 08/78/31 and 08/78/03 have to be considered. Table 7.8 gives the statistics for all 30 samples considered as a complete population. Values of C.V. vary between 4% and 28% for site 31, and 3% and 18% for site 03, depending upon the metal considered. These values represent the combined within site sampling error and the analytical variation in the data. For Cu, Pb, Zn and Cd this variation is greater at the contaminated 1 Statistics for Replicate Sediment Analyses cr c A) Sites on River Ecclesbourne M 3 H* fl> 08/78/328 -J W Cu Pb Zn Cd Fe% Mn Ca Mg N=30 CD Mean 43.4 7310 1304 17.7 1.99 793 3.32% 1623 T> 5.23 3 S.D. 811.8 180.4 3.55 0.15 109.6 0.37 110.5 C.V. 12.1 11.11 13.8 20.1 7.5 13.8 608 fD 11.1 X Max. 52.0 10040 1936 26.4 2.32 1000 4.24 1840 O ft) Min. 36.0 5760 1068 12.8 1.76 640 2.92 1480 08/78/351 ppm N=30 2 t V Mean 29.3 841 462 3.7 2.92 —. 3154 1024 II ft) i h S.D. 2.60 65.8 20.9 0.65 0.14 — 227.1 60 M C.V. 8.9 7.8 4.5 17.6 4.8 7.2 U1 3 ft) — 5.9 0 3 W Max. 36.0 1004 512 4.8 3.24 — 3600 1120 1 or Min. 24.0 732 416 2.0 2.72 — 2680 920 fD DJ H ft- (D 0Hi Q» B) Sites on Minsterley Brook M OJ I 3 08/78/31 N=30 U II Mean 730 21502 26020 196.9 1.96 3871 15.03 1920 3 H* S.D. 202.5 2978 5534 35.2 0.07 1.00 114.1 W 161.6 W C .V. 27.7 13.9 21.3 17.9 3.6 4.2 6.7 5.9 H« Max. 1120 29400 42040 272 2.08 4200 17.00 2120 IQ Min. 400 17920 19640 148 1.84 3520 13.20 1760 a (JU+ 08/78/03 N=30 0) Mean 49.3 1511 • 1807 14.1 3.27 1907 1.17 4221 S.D. 8.8 234 56 1.43 0.11 172 0.08 172.9 C .V. 17.9 15.5 3. 10.1 3.4 9.1 6.8 4.1 Max. 76.0 2000 1920 16.4 3.56 46 Min. 2280 1.32 00 39. 2 1120 1704 12,0 3.04 1560 1 .04 4000 -251 - site 31 than at 03, For the other elements, errors are of the same order of magnitude at both sites. A further breakdown of the data into results for the individual samples at each site (Table A4.18) shows that variation due to analytical error, with one exception, is quite low at both sites. It is generally less than 5% and often as low as 1-2% for all the elements. The variation between subsamples within sites has been compared with the between replicate var- iation using 1-Way Analysis of Variance (1-Way ANOVA). The results are given in Table 7.9A. For the Minsterley sites (031 and 03), with the exception of Cu and Zn at site 03, the between sample variation is generally highly significant compared with the variation between analytical replicates. This confirms the comments above in- dicating that sampling error is the more signifi- cant component of the variation found in the data. The variation between subsamples has also been compared with the variation between the sites using 1-Way ANOVA. The results are given in Table 7. 9B and indicate, as would be expected, that the diff- erences between the sites are highly significant. The test simply shows that the variability in the data due to sampling/analytical errors does not mask the difference between the sites. This would be anticipated from the choice of sites; i.e. a -252- Table 7.9 Results of 1-Way ANOVA Performed on Replicate Sediment Data. A Between Samples Sites on Minsterley Brook Element F-Ratio Site 03 , Site 31 Cu 37.40** 2.50 Pb 22.32** 24.79** Zn 18.42** 2.62 Cd 51.28** 173.09** Fe 3.08* 11.46** Mn 16.16** 6.68** Ca 3.13* 14.62** Mg 78.49** 31.73** Sites on River Ecclesbourne Element F-Ratio Site 328 Site 351 Cu 10.26** 2.03 Pb 4.31** 1.74 Zn 3.50* 2.08 Cd 26.77** 0.99 Fe 15.04** 23.52** Mn — — Ca 13.69** 15.66** Mg 11.91** 5.23** * Significant at p = 0.05 ** Significant at p = 0.01 -253- (Table 7.9 contd.) B Between Sites Minsterley Brook Sites 03 and 031 Element F-Ratio Cu 65.92** Pb 291.41** Zn 125.52** Cd 152.50** Fe 890.83** Mn 534.41** Ca 2486.49** Mg 716.50** River Ecclesbourne Sites 328 and 351 Element F-Ratio Cu 50.05** Pb 691.84** Zn 265.13** Cd 94.40** Fe 138.15** Mn — Ca 351.87** Mg 175.21** -254- highly contaminated site and a control site. The test would have been more significant for sites where the contrast was less extreme. The above results show that even within a distance of 50 m considerable detailed variation in stream sediment trace metal geochemistry occurs. This variation must clearly be minimised for re- petitive seasonal sampling. Marking sampling sites in the field is one way in which this can be achieved. The variations in data due to analytical errors are relatively small, and generally about half that of the sampling errors. Sampling error is greater at the upstream contaminated site (31) than at the downstream site (03) for Cu, Pb, Zn and Cd. This might be anti- cipated from the nature of the stream sediments at site 31. Here the sediment comprises poorly sorted shoals of mine waste with some locally der- ived shale material. In addition the metals occur commonly in discrete sulphide mineral grains (see Section 7.7). These factors will both contribute to problems in obtaining homogeneous samples re- presentative of the sediments at the site. The situation at site 03 is very different; sediments occurring in a well mixed bank with fewer sulphide minerals present, making representative sampling easier. -255- To relate these observations to the Minsterley seasonal data is difficult as the experimental design does not allow strict statistical comparison of the variations of different origins. That is, the %sampling/analytica l component of the variation cannot be separated from any component due to sea- sonal effects. An experimental design similar to that employed by Chork (1977) is necessary to achieve this. However, if the C.V. values for the replicate data for sites 31 and 03 are compared visually with the corresponding coefficients of variation for the year, the latter are generally higher. This implies that variations in sediment metal concentrations occur which are additional to the variation that can be expected from sampling and chemical analysis. The C.V.s for the year's Pb data are of the same order as the replicate values at both sites, 14% and 16% respectively, suggesting that most of the variation in this data is due to sampling error and, to a lesser extent analytical error. Analy- tical error will become a more major factor in data variation where the element occurs at con- centrations close to the detection limit. This is the case for Cd at such sites as 02 and 132 where the annual C.V. values are very large ( } 50%) (see Table A4.7). A lot of this variation is attrib- utable to analytical "noise" which becomes more apparent at low level determinations. Where a dilution factor is employed in the analytical % HtsVeA (\wo\s^*>\<> cjl \Jcx.»\ technique, this noise is multiplied thus giving a disproportionately high degree of variation to the data. The significance of the variation between sampling occasions has been compared with the bet- ween site variation using a 2-Way Analysis of Var- iance (2-Way ANOVA) Davis (1973) (Table 7.10). The between occasion variation is statistically sig- nificant relative to the between site variation for Cu, Zn, Fe and Mn, but not for the other ele- ments. The results for Cu and Zn contrast with those of Chork (1977) who found no such differences between sampling periods. He only sampled on three occasions, however, and does not quote data for Ca and Mg. The largest variations in sediment concent- ration occur at site 33. Here the mine dump is adjacent to the river and is the principal contri- butor to the stream sediment. This can be seen from the high Ca levels in the sediment which are identical to those in the dump itself (c. 30% w/w Ca in waste material compared with 0.1% in local shales). The inhomogeneity of the dump material for Cu, Pb, Zn and Cd is evident from the analyses quoted in Section 7.1. This will lead to variation in the sediments, probably on quite a localised scale leading to high sampling errors. In addi- tion, during high stream flows and heavy rainfall, -257- Table 7.10 Results of 2-Way ANOVA Performed on Minsterley Sediment Data Cu F Sig Pb F Sig B.S. 86.836 P< 0.01 B.S. 86.431 P< 0.01 B.O. 2.914 P <0.05 B.O. 0.216 N.S. Zn F Sig Cd F- Sig B.S. 141.55 P< 0.01 B.S. 116.924 P < 0.01 B.O. 2.924 P< 0.05 B.O. 2.109 N.S. Fe F Sig Mn F Sig B.S. 85.127 P < 0.01 B.S. 56.873 P< 0.01 B.O. 6.241 P < 0.01 B.O. 3.752 P < 0.01 Ca F Sig Mg F Sig B.S. 80.735 P < 0.01 B.S. 13.202 P< 0.01 B.O . 0.595 N.S. B.O. 2.237 N.S. B.S. Between Site F = Variance Ratio B.O. Between Occasions Sig - Significance N.S, Not Significant -258- large quantities of material are eroded from the dump and washed downstream. Shoals and banks of sediment present at one occasion may have disappeared completely by the next sampling occasion. Small dis- crete mineral particles also tend to be winnowed away by reworking of sediment banks, causing de- pletion in heavy metals. This process is important here as it is probable that thfe majority of the metals occur as discrete sulphide grains derived from the mine dump (see Section 7.7). 7.3.4. Variations in River Ecclesbourne Sediment Data Similar observations concerning the decrease in the range in metal concentrations over the year from anomalous to control sites can be made for the data collected from sites on the River Ecclesbourne. In particular the range in values for Pb at the highly anomalous site 318 (max=52 OOOppm, min=6320ppm) is very large (see Figure 7.9). Reference to the replicate sediment analyses for site 328 (anomalous) and site 351 (control) (Tables 7.8 and A4.18) reinforces the earlier points concerning sampling and analytical variability. Analytical precision expressed by C.V. values is consistently good for all elements at both sites - generally between 1% and 6%, though for Cd it is higher - between 5% and 20%. The results of the 1-Way ANOVA comparing samples -259- and replicates (Table 7.9A) show that for site 328 (contaminated) the between sample variation is statistically significant compared with the between replicate variation for all elements. For site « 351, with the exception of Fe, Ca, and Mg, all elements show statistically significant variation between subsamples compared with the between re- plicate variation. The values for the subsample C.V.s for each element for site 351 (Table A4.18) are similar to those for the total population (Table 7.8). There is also appreciable decrease in analytical precision (except for Cd) for the replicates at this site compared with the replicate analyses for other sites (Table A4.18). The results of the 1-Way ANOVA for Cu, Pb, Zn, Cd and Mn at site 351 are thought therefore to be due to decreased sampling errors related, perhaps, to better sorted sediments in this part of the river. Table 7.9B shows that between site variation is highly statistically significant compared with between subsample within site variation. This would again be anticipated from the choice of sites used in this experiment. The inference can again be drawn from the data that the sampling error for Cu, Pb, Zn and Cd at the contaminated site is higher than at background areas. The reason for this is thought to be rel- ated to the occurrence of discrete mineral grains -260- in the sediments such as those found at site 318. A visual comparison between the C.V.s for sites 4 328 and 351 for the years data (Table A4.12) and those for the replicate analyses (Table 7.8) again indicates that a variation in concentration occurs for most elements which is apart from simple sam- pling errors. There are exceptions to this, how- ever. The C.V. at site 328 for Mn for the years data is nearly the same as for the replicate data and data for the six sampling occasions for Ca at both sites have a smaller C.V. than the replicate data. This could suggest that very small variat- ions occur between sampling occasions but that re- presentative sediment sampling for Ca is difficult. At site 328, Mg exhibits similar behaviour. The results of the 2-Way ANOVA (Table 7.11) contrast with those of Minsterley Brook in that significant differences between occasions only occur for Fe and Mn. Differences between sites are statistically significant for all elements. The results for Fe and Mn would be anticipated from the plots of these two elements (Figure 7.10), which show that the range in concentrations which occur over the year are of the same order of mag- nitude, and are occasionally much greater than the between sites variation. -261- Table 7.11 Results of 2-Way ANOVA Performed on Ecclesbourne Sediment Data Cu F • Sig Pb F Sig B.S. 79.951 P 0.01 B.S. 50.377 P 0. B.O. 1.546 N.S. B.O. 0.176 N.S Zn F Sig Cd F Sig B.S. 84.129 P 0.01 B.S. 84.129 P 0.01 B.O. 0.585 N.S. B.O. 0.585 N.S. Fe F Sig Mn F Sig B.S. 14.858 P 0.01 B.S. 6.572 P 0.01 B.O. 2.671 P 0.05 B.O . 3.997 P 0.05 Ca F Sig Mg F Sig B.S. 76.605 P 0.01 B.S. 180.77 P 0.01 B.O. 1.474 N.S. B.O. 1.190 N.S. B.S. = Between Sites Not Significant B.O. =• Between Occasions Significance -262- 7.3.5. Metal Dispersion in Waters in Minsterley Brook Cu, Pb, Zn and Cd The copper dispersion for filtrable and total exchangeable heavy metals contrast with the Cu plot for sediments (see Figures 7.7, 7.11 and 7.12). Filtrable Cu concentrations decline grad- ually from 4ppb to control levels of about 2.5ppb at site 134. Total Cu levels rise from site 33 (5ppb) to a maximum mean value of 6ppb at sites 28 and 30 before declining to 3ppb at site 134. Total Cu concentrations at control sites (02 and 132) are approximately 3ppb. The plot for filtr- able Pb (Figure 7.11) is a better defined curve than for Cu. Peak Pb values occur at site 31 (about 57ppb). However, levels at site 134 (about 6ppb) are still twice those at control sites (about 3ppb). Mean concentrations for total exchangeable Pb describe a less well defined curve. The peak mean level is 175ppb at site 31 falling to 15ppb at site 134. This figure is still over twice levels at control sites (about 6ppb). The mean Zn plots, both total and filtrable (Figures 7.11 and 7.12) show two peaks; the first at site 31 (1420ppb (F), 1600ppb (T)) and the se- cond at site 107 (700ppb (F) , 990ppb (T)). A sec- ondary peak in the data at site 107 probably re- lates to the input of Zn from the Boat Level adit 2000 -Cadmium Copper ppb iku Ji n j PPb l\ •rTf 129 33 31 30 2S 107 Fig 7.11 \r Dispersion Plots for Filtrable Cu Pb Zn and Cd Minsterley Brook Ni N^t 129 73 31 30 28 107 10 9 3 126 2000 Copper .Zinc. ppb ppb TI A 129 33 31 30 26 107 10 9 3 12« 134 N. 129 33 31 30 28 107 10 9 3 12S 0 2 ikm Leod Cadmium ppb 20 ppb 10 VLi 1 1 T_ 129 i 3 31 30 2 8 107" 10 9 3 126 "Fig 7.12 7i TS—; Dispersion Plots for Total Exchangeable 129 33 31 30 2? 107 10 5 3 i?5 fit" Cu(Pb,Zn and Cd - Minsterley Brook -265- via the tributary stream entering below site 28. High levels of Zn were found in this water (site 124, filtrable Zn=1600-2500ppb). Levels of Zn at site 134 are still elevated above those at control sites (site 134, Zn (F) = 79ppb, Zn (T) = 103ppbj control levels, Zn (F) = 6-lppb, Zn (T) = 12-60ppb.). The cadmium levels decline steadily from site 33, and do not display the secondary peak at site 107. Concentrations at site 134 correspond closely to control site values of c. 0.5ppb filtrable Cd and 0.7ppb total Cd. Fe and Mn The dispersion plots (Figure 7.13) for these elements show no distinct trends. The dispersion of total exchangeable metals follows the filtrable patterns quite closely. Ca, Mqt and pH The Ca and Mg dispersion plots follow similar patterns (Figure 7.14), with concentrations increa- sing slowly from site 33 to site 10, then with a sharp rise in Rea Brook (sites 9-134). The dis- persion of Ca in water contrasts with the sediment dispersion pattern. The shape of the Ca and Mg plots also reflect the very different major cation chemistries of Rea Brook and Minsterley Brook. The former has a mean Ca concentration of 90ppm and Iron Mongontse 400] ppb ppb 2001 Kj I/. 1A NlH "XT: i i 129 33 31 30 28 107 10 9 3 128 129 3 3 31 30 2 8 107 10 9 3 1J6 0 2 tkm Manganese dotal) 200 Iron (tolol) ppb 1500 100 i\ PPb ...— —' 1 I ^ 1000 111 i 129 33 31 30 2 8 107 10 9 3 128 131 Fig 7.13 /i /I Dispersion Plots for Filtrable and Total Exchangeable Fe and Mn-Minsterley Brook 129 33 31 30 28 107 10 9 3 1:8 134 100 Calcium ppm 50 J I J y rr 129 33 31 30 28 107 10 9 3 126 0 2 tkm 129 33 31 30 28 107 10 9 3 126 134 Magnesium Fig 7.U ppm Dispersion Plots for Filtrable Ca and Mg and pH - Minsterley Brook r-T rJL J^i 'ft1! 129 33 31 30 2ft 107 10 9 3 126 131 -268- mean Mg of 13ppm, (site 105, Table A4.9), contras- ting with mean levels 45ppm Ca and 7ppm Mg at site 28, for example. Some dilution of Rea Brook obv- iously occurs with the input of Minsterley Brook and this is reflected in the dispersion patterns for Ca and Mg. The mean pH of the river water gradually in- creases from c. 7.0 at site 33 to c. 8.0 at site 134 (Figure 7.14) . These values are typical for a non-polluted river, which usually range between 6.5 and 8.5 (Hem 1970). A pH of 6.0-7.0 is high, however, for sulphide mine drainage water which is often as low as 2.0 or 3.0 (Foster et al 1978). The dissolution of CaCO^, abundant as calcite gangue mineralisation, probably neutralises the acidic water giving the relatively high pH. The higher Ca concentrations, and pH, in Rea Brook probably reflect the geology of the Rea Brook valley. This lies between the Shelve inlier in the south east and the Long Mountain in the north east. The rocks comprising this narrow band belong to the Wenlock series, consisting, in this area, of cal- careous siltstones and shales. An additional factor is the intensive agriculture, largely arable, which is practised in the.Rea Brook floodplain. This will contribute Ca to the brook in run-off waters from limed and fertilised fields. Although lower Ca levels occur in Minsterley Brook, they are higher -269- than would be anticipated from the geology of the area. The calcite occurring in the mineralised areas is probably the major influence on the Ca chemistry here, although agricultural lime may again constitute an additional source. 7.3.6. Metal Dispersion in Waters in' the River Ecclesbourne Cu, Pb, Zn, Cd Dispersion for Cu (filtrable and total) and Zn, (filtrable and total) follow well defined curves downstream from maxima at site 318 (Figures 7.15 and 7.16). Mean Cu values peak at 6.3ppb (F), llppb (T) , and Zn 85ppb (F) and 124ppb (T). Total and filtrable levels of these elements have reached control site concentrations at site 325 (c. 30ppb Zn (F), c. 40ppb Zn (T), c. 3ppb Cu (F) and c. 4ppb Cu (T)). The concentrations of Pb, Zn and Cd are generally lower than mean peak values at sites 33 and 31 on Mins- terley Brook (cf site 31, Pb (F) = 57ppb, site 31, Pb (T) = 175ppb, site 31, Zn (F) = 1432ppb, site 33, Cd (F) = 17ppb). The peak mean Cu concentration is higher in the Ecclesbourne (site 318, Cu (F) = 6.3ppb, compared with site 33 Cu (F) = 3.9ppb). Downstream dispersions for Pb and Cd for both total and filtrable phases follow no specific trends (Figures 7.15 and 7.16). Peak mean filtrable Pb occurs at site 352 with a value of c. 13ppb, with a corresponding mean maximum total Pb of c. 40ppb. 10 Copper 300 .Zinc. ppb 200 ppb 100 i i" 3S2 316 328 321 338 325 327 351 i N) 0 1 352 JIB 328 321 336 325 327 351 0 i 2km Codmium ppb Ki ppb 1 1 352 318 328 321 338 325 327 351 Fig 7.15 \J Dispersion Plots for Filtrable Cu Pb Zn and Cd — River Ecclesbourne \L \ r i 352 31® 324 321 336 325 3 27 351 Copper 200 •Cqdrclum. ppb 1 1 352 318 328 Fig 7.16 Dispersion Plots for Total Exchangeable Cu.Pb.Zn and Cd River Ecclesbourne -272- Mean maximum Cd values are 1. 5ppb (F) and 2.1ppb (T) both occurring at site 318. Secondary lesser maxima for both elements in both phases occur at site 336 (llppb Pb (F) , 1. 2ppb Cd (F), 41ppb Pb (T) and 1.8ppb Cd (T)). This might reflect a run-off input from the nearby railway embankment, although corresponding changes in concentration are hot apparent for the other heavy metals. Levels very close to those at control sites are attained for both metals by site 351 (Tables A4.14 and A4.15). Concentrations at control sites for the four elements are essentially the same for the two areas. Fe and Mn Mean levels of total and filtrable Fe decrease sharply away from maxima at site 352, to minimum values at site 328 (Figure 7.17). The level of filtrable Fe then gradually rises with distance downstream from this site. Mean total exchangeable Fe is more erratic in behaviour, but generally dis- plays a trend of increasing concentration downstream. Mean levels of total and filtrable Mn also fall sharply from maxima at site 352 (159ppb (F), 216ppb (T)) and continue to decline steadily downstream to mean values of 39ppb (F) and lOlppb (T) at site 351. The high concentrations of Fe and Mn encoun- tered at site 352 reflect the. input of these metals from the western tributary sampled at site 315. -273- Mean levels of Fe and Mn in both sediments and water are higher here than anywhere else in the catchment (Fe (S) = 5.09% w/w, Fe (F) = 80ppb, Fe (T) = 512ppb, Mn (S) = 2616ppm, Mn (F) = 230ppb, Mn (T) = 357ppb) . The origin of these high levels in this tributary is not clear. A single sample was taken at site 315/A (SK279528) about 400 m upstream of site 315. Levels of Fe and Mn in se- diments are the same as for site 315 (Fe 5.48% w/w, Mn 3280ppm) and soluble and total levels are also very similar. There are no buildings in the upper part of the stream above site 315/A, although its course runs close to mineralised limestone outcrops. Mn mineralisation (known as "wad") along with pyrite are common secondary minerals associated with the lead veins and could account for the elevated levels of these elements in this stream. Ca, Mg and pH The dispersions for Ca and Mg contrast markedly (Figure 7.18). Ca falls steadily from a peak mean value of 88ppm at site 352 to 57ppm at site 351. The mean Mg level rises, however, from lOppm at site 352 to 12.4ppm at site 351. The Ca dispersion reflects the increasing dilution of calcium car- bonate rich sources of water of the Ecclesbourne in the limestone north of Wirksworth by ground and run-off water derived from the sandstones and shales of the Millstone Grit series and Triassic pebble beds. 300 J iCflCL Mongonese ppb 2004 T T T T Nl i T i i i 1 -IV 321 338 325 327 351 Jil 328 331 338 325 327 HI 0 1 2km 1175 ppb Mongoneselto(ol) 500^ ppb 352 318 328 338 325 Fig 7.17 Dispersion Rots for Filtrable and Total Exchangeable Fe and Mn - River Ecclesbourne jijjia Jit «t J38 J25 JJr JJT 100 Calcium N 352 318 326 321 336 325 327 351 0 1 2km Y1 352 318 328 321 336 325 327 351 Fig 7,18 Dispersion Plots for Filtrable Ca and Mg and pH - River Ecclesbourne -276- Levels of Ca in the upper part of the Ecclesbourne are comparable to those occurring in Rea Brook. The pattern of Mg dispersion is not easily accounted for, but is perhaps influenced by run-off from the Triassic rocks, containing gypsum along the south western edge of the catchment. Studies conducted by the Applied Geochemistry Research Group on other rivers have also shown an " increase in Mg concentration^ It is thought that this may reflect an input from the soil (Thornton, 3981, pers. comm). The mean pH of the Ecclesbourne drops by c.O.lpH units downstream from the sewage effluent (Figure 7.18). It then rises to and remains at approximately 7.6. This value lies almost exactly in the centre of the range suggested by Hem (1970) for unpolluted river water (pH 6.5-8.5). The sewage effluent which enters just upstream of site 318 has a mean pH of 7.15, which is reflected in the river water pH at this site. 7.3.7. Variations in Metal Concentrations in Water Large variations in the data occur through- out the year for both filtrable and total exchan- geable heavy metals. There is a general trend amongst filtrable Cu, Pb, Zn and Cd for a greater variation to be present at contaminated sites (see Figures 7.11 and 7.15). However, this is not as clearly established as for sediment data. The -277- relative amounts of variation, as expressed by C.V. values are similar for the two catchments for fil- trable Cu and Pb (Tables A4.8 and A4.14). Greater variation (x 2 approx) is found in the Zn and Cd data for the Ecclesbourne. The relative variations for filtrable Fe and Mn are also similar in size for the two rivers and for individual sites on the rivers (Figures 7.13 and 7.17). Typically C.V. values are about 50%, although sites on Minsterley Brook have C.V.s of c. 100%. Ca, Mg and pH tend to have lower C.V. values for both rivers, usually c. 10% for Ca and Mg and 2-4% for pH. The data for replicated filtrable water samples (Tables 7.12 and 7.13) show that for most elements the levels of precision expressed by the C.V. are generally less than 10% and often less than 5%. These values are quite acceptable for these analyses. Where elements occur at concentrations close to the detection 1 imit, reproducibility decreases and is usually greater than 15% and can be as high as 50% (see for example Cd, site 02). The replicate total exchangeable metal data usually have C.V. values higher than the corresponding filtrable samples. Possible reasons for this are given below. However, values of the C.V. are generally of the order of 5%, though again, for metals at levels close to the detection limit, values of C.V. of 15% to 20% occur. -3 Analyses of Replicated Water Samples from Minsterley Brook DJ tr H fD Site 31 - Filtrable 02/78 Cu Pb Zn Cd Fe Mn Ca Mg NJ Mean 4.4 31.5 695 8.3 64 88 S.D. 0.18 1.1 8.7 0.28 4.1 2.5 — — C.V. 4.1 3.5 1.3 3.4 6.4 2.8 — - 06/78 Mean 3.1 68 1359 13 52.5 70* 49.5 6.1 S.D. 0.18 4.92 47.2 0.35 7.5 0 0.86 0.09 C.V. 5.9 7.2 3.5 2.7 14.3 0 1.8 1.4 I tsJ 08/78 CD I Mean 3.6 54 1930 16.8 41 103 4.8 7.0 S.D. 0.1 2.7 41 0.4 3.8 4.3 1.1 0.3 C.V. 3.4 5.1 2.1 2.6 9.3 4.2 2.4 3.7 10/78 Mean 2.5 52 2069 21.5 34 85 57 6.3 S.D. 0 1.5 16 1.8 1.5 3.5 2.2 0.2 C.V. 0 2.9 0.8 8.4 4.4 4.2 3.9 2.7 Site 31 - Total Exchangeable 0»-J3 or 02/78 Cu Pb Zn Cd Mn M (D -J Mean 8.7 381 1012 12.7 146 S.D. 0.36 7.35 19.6 3.56 3.40 C.V. 4.1 1.9 1.9 28.0 2.3 t\) O 0 06/78 3 rt a Mean 4.2 125 1454 16.5 74.5* S.D. 0.23 5.79 47.2 0.59 C.V. 5.5 4.6 3.2 3.6 N) 08/78 I Mean 4.4 89 2003 19.9 44 S.D. 0.11 4.74 37.28 0.55 4.10 C.V. 2.5 5.3 1.9 2.8 9.3 10/78 Mean 3.3 83 2146 23.4 89 S.D. 0.19 0.83 17.01 1.78 3.37 C.V. 5.8 1.0 0.8 7.6 3.8 Units i heavy metals t ppb Number of replicates = 4 Ca and Mg i ppm * i N =2 -280- Table 7.12 (contd.) ID H O^ 00 CN «H ID n ch cn ... • • • • • • 2 r* O rH r- o o r- o cn. a> O CN m rr00i r^- O ... O cr> o r- vo ro VD CN r-4 • • . . in . O ^ ^ H (N O CN ID CN in CN o vd in ^ o ^ ^ n ^ h ... (N CTi • • • • • • O 00 oo o ^ en o ^ r- o cn in rOH• • H• o oo n h in cn cu cn f—i ^J* LO iH • • o • • ft. r- o o oo HCOh ro in CN 00 (D CO CN r- rH CN V • • • ... U o o o o o cn o o 00 o o r- V CN in 00 tH »—1 in CO 00 NT cr> ^r "^r O CO CO CO ^ CO ja • • • • • • • • • m a, CN O ^ CN O ^ noH inoM . 1 « rH rH rH «—i 0) H unj 4-» in in r- rH in i—1 CJiOvD fO OH ro cn cn CN rH o •H p • • • • * • • • • • . • u HON cn o n cm O cr> rH o cn 1 rH CN O CO 00 00 00 Q) C • • r- C - • r- C • • C • • rt Q> \ rtf Q > fd Q > \ rt Q > -H \ Q) . . <£> Q) • • \0 0 Q) • . o Q) . . W o 2 o o o s w a o 2 w U rH S w O Site 02 - Total Exchangeable BJ 04/78 Cu Pb Zn Cd Xf Fe Mn Hfl> Mean 2.2 5.4 6.8 0.3* 167* 16.6 S.D. 0.11 0.42 0.70 0.55 C.V. 4.9 7.8 9.7 3.3 N3 o o 06/78 rt a Mean 2.7 2.9 5.6 0.3 167.5 17.9 S.D. 0.08 0.41 0.37 0.04 17.5 1.43 C.V. 3.0 14.4 6.6 13.3 10.4 8.0 i NJ 08/78 CO Mean 2.6 6.1 9.7 0.5- 258 20.8 S.D. 0.15 0.74 0.59 25.6 2.08 C.V. 5.8 12.1 6.1 9.9 10.0 10/78 Mean 1.3 5.8 28.0 0.9 101 19.7 S.D. 0.1 0.83 1.30 0.15 4.15 0.96 C.V. 7.7 14.3 4.6 16.7 4.1 4.9 Units t heavy metals : ppb N = 4 except for *, where N = 2 Ca and Mg : ppm Table 7.13 Analyses of Replicate Water Samples from the River Ecclesbourne Site 318 - Filtrable 02/78 Cu Pb Zn Cd Fe Mn Ca Mg Mean 2.7 2.5 84 1.65 11.75 92.5 S.D. 0.07 0 1.09 0.15 0.75 4.33 C.V. 2.6 0 1.3 9.1 6.4 4.7 04/78 Mean 4.4 2.5 41 0.8 12.3 12.3 88 10.9 S.D. 0.07 0 1.87 0.17 0.62 7.1 4.90 1.03 C.V. 1.6 0 4.6 21.5 5.1 57.8 5.6 9.4 06/78 i ro Mean 7.8 5.4 44.8 86.3 55 00 <0.2 M S.D. 0.48 0.22 2.27 0 8.2 3.54 I C.V. 6.1 4.0 5.1 0 9.5 6.4 08/78 Mean 5.4 4.8 32 0.8 84 48 89 10.55 S.D. 0.27 0.56 0.83 0.04 4.15 2.12 1.73 0.17 C.V. 5.0 11.7 2.6 5.0 4.9 0.5 1.9 1.6 Site 318 - Total Exchangeable »-3 tf H ro 02/78 Cu Pb Zn Mn Mean 4.8 28.4 111 114 S.D. 0.19 3.05 3.77 2.05 u> C.V. 4.0 10.7 3.4 1.8 o o ri- 04/78 a Mean 9.9 25.4 85 124 S.D. 0.38 3.58 7.28 15.94 C.V. 3.8 14.1 8.6 12.8 i NJ 06/78 00 OIJ Mean 19.7 36 96.5 179 S.D. 1.54 2.03 3.57 9.60 C.V. 7.8 5.6 3.7 5.4 08/78 Mean 8.1 22.0 61.5 427.5 115 S.D. 15.8 0.9 2.5 16.01 2.38 C.V. 14.3 4.1 . 4.0l 3.7 2.10 Units i heavy metals t ppb Ca and Mg i ppm N = 4 Site 331 - Filtrable 0) 02/78 Cu Pb Zn Fe Mn Ca Mg tr w Mean 1.65 <2.5 8.5 22.5 (D 12 -J S.D. 0.30 0 0.5 3.35 0.71 C.V. 18.2 0 5.9 14.9 5.9 M. (jJ o 04/78 o rt a Mean 2.0 <2.5 6.15 33.8 59.5 14.3 S.D. <2.0 0.12 0 0.09 3.63 0 2.18 0.59 C.V. 6.1 0 1.4 10.8 0 3.7 4.1 06/78 N) 00 Mean 3.8 <2.5 26.1 246 455* S.D. 0.55 0 2.01 37.8 0 I C.V. 14.5 0 7.7 15.4 0 08/78 Mean 2.8 4.0 7.0 160 51 65 15.25 S.D. 0.23 0.94 0.47 17.68 0.83 0.33 C.V. 1.0 8.2 23.5 6.7 11.1 1.6 1.5 2.2 02/78 Cu Pb Zn Cd Fe Mn Mean 2.0 5.25 12.1 0.8 159 20.5 S.D. 0.36 0.25 0.43 0.15 14.9 1.37 C.V. 18.0 4.8 3.6 18.8 9.4 6.7 04/78 Mean 2.6 ^2.5 10.3 0.75 174 17.6 S.D. 0.15 0 0.51 0.17 21.17 2.53 C.V. 5.8 0 4.95 22.7 12.2 14.4 06/78 Mean 5.15 <2.5 35.7 0.95 541 557.5 S.D. 0.26 0 1.08 0.15 22.19 61.9 C.V. 5.0 0 3.0 15.8 4.1 1.1 08/78 Mean 4.45 11.1 14.6 1.3 670 89 S.D. 0.32 0.41 1.07 0.13 74.6 4.06 C.V. 7.2 3.7 7.3 10.0 11.1 4.6 Units i heavy metals i ppb N as 4, except when shown Ca and Mg i ppm where N = 2. -286- Total exchangeable heavy metals in both rivers exhibit consistently large variations throughout the year. (see Figures 7.12, 7.16 and 7.17, and Tables A4.10 and A4.16). For example, total Pb in Minsterley Brook ranges between 31ppb and 585ppb (mean = 169ppb) at site 30 and between 83ppb and 392ppb (mean * 175ppb) at site 31. Iron shows similar large variation, for example, the concen- tration of total Fe has a range of 1600ppb at site 107 (mean = 551ppb) • Equivalent variations for filtrable metals at the same site aret site 31; Pb, 32-69ppb (mean = 57ppb) , site 30; Pb, 20-85ppb (mean = 44ppb) , and site 107; Fe, 30-413ppb (mean = 159ppb) . It is evident from this, and by com- parison of the data for total and filtrable metals that, relatively, the variation in total metal data is greater. This would be anticipated as the total exchangeable metal values contain a measure of the heavy metals associated with particulate matter. Two variables are introduced, the actual concentration of particulate matter in the sample, and secondly the amount of metal associated with it. The former is highly variable and very dependant on flow as can be seen from Table 7.14. The data for 04/78 Minsterley illustrates the effect of a large and sudden storm on suspended solids concentration. Sites 3 to 134 were sampled before the others, and during the intervening 8 hours a large storm occurred which more than doubled the flow in the river and had a similar effect on the suspended solids concen- Table 7.14 Concentrations of Suspended Solids in Streamvater Samples Minsterley Brook Date 129 33 31 30 28 107 10 9 3 126 134 • Flow 04/78 35.9 26.7 21.8 28.9 87.8 81.2 64.1 65.6 7.5 9.1 10.1 1.851/0884 06/78 22.7 5.4 6.6 4.3 5.5 4.2 9.2 12.0 12.7 9.6 10.6 0.641 08/78 10.8 12.2 1.9 2.8 3.7 6.7 7.2 12.8 9.0 9.8 7.7 0.397 10/78 13.2 4.3 3.7 1.0 3.6 2.5 8.0 7.3 7.8 4.5 6.4 0.260 River Ecclesbourne Date 352 318 328 321 336 325 327 351 Flow 02/78 17.0 13.2 14.1 a. 8.2 7.7 7.4 8.2 1.016 04/78 7.4 12.6 7.5 7.8 5.3 4.8 3.6 49.4 0.443 06/78 4.9 22.3 5.5 5.5 2.0 3.4 0.7 4.7 0.158 08/78 10.8 33.2 10.1 7.4 15.3 4.9 5.8 5.8 0.476 Units i Suspended Solids % ppm t Flow i Cumecs Flow recorded at site 327 on the Ecclesbourne and site 134 on Minsterley Brook. Flow Data for 04/78 on Minsterley Brook split to show the effect of the storm referred to in the text. -288- tration. The large value at site 04/78/351, was a result of engineering works on the river channel about 2.5 Km upstream of the site. As can be seen, the work disturbed large quantities of river sedi- ment and soil from the banks. The variations due to the hydrodynamics of suspended solids is additional to the variations in the metal chemistry of the material itself. Variations in* the chemistry of the suspended solids are complex and insufficient detailed data is available in this work. In addi- tion to chemical reactions, e.g. adsorption-desorption processes and precipitation, the nature and origin of the material will vary with flow conditions. That is, during low flow, fine material largely derived from the water channel itself will be en- trained in suspension. With increase in flow larger particles will be entrained, leading ultimately, at high flows when the critical erosion velocity is ex- ceeded, to transport of bedload. In addition, higher water levels will flood otherwise dry parts of the chan nel and will erode additional material with a resultant increase in the suspended load. A further complication to the interpretation of chemical data for suspended solids is that the material sampled at a point in the river will have been derived both from sources upstream of that point as well as at the site itself. Material can be derived from clastic erosion of contaminated river banks as well as resuspension of bed sediments. -289- This combination of processes makes it difficult to relate data for suspended sediments to that for bed sediments (see Section 7.5). Suspended mat- erial, during normal flow regimes will typically comprise clay particles, organic material, Fe and Mn oxide particles, minerals and precipitates and diatoms, between 0.5 and 3 in size (Wood 1978) . The clays, oxide particles and certain organic material are highly surface active and can adsorb large amounts of trace elements. If the chemical compositions of the suspended solids are expressed on a dry weight basis, it can be seen that very high concentrations of heavy metals occur (see Table 7.15 and 7.16). Levels of metals in suspended particulates decrease steadily downstream. This can be due either to desorption of trace metals and dissol- ution of precipitates or to "dilution" with suspended matter low in trace metal content. The latter case seems more likely for both rivers, as the high pH of the water would tend to favour adsorption and precipitation reactions. There are also many pot- ential sources from non-contaminated tributaries for sediment of lower metal content (e.g. site 02, Minsterley Brook, site 331, River Ecclesbourne). Potential variation in the total exchangeable data will be further increased as the method of determination is by adding two measurements, the -290- Table 7.15 Chemical Composition of Suspended Solids from Minsterley Brook - Sampling Occasion 08/78 Cu« Pb Zn Cd Fe Mn 129 37 463 648 83 34722 3796 33 57 2049 8279 iao 22541 2705 31 421 18421 38421 1632 28947 1316 30 321 6964 15000 393 16071 1071 28 189 3243 7838 189 14865 1622 107 104 1716 6866 209 5672 1194 10 56 1042 7639 139 15972 1389 9 39 1289 4766 63 14063 2109 3 56 1167 3556 67 16666 3111 126 41 1020 2449 82 16837 4388 134 52 909 1948 26 17532 4675 Tributary Sites 029 26 1948 2273 40 23377 2727 105 50 417 300 17 20833 2500 02 51 525 390 34 23729 2170 132 29 377 176 0 23529 4118 Units : ppm (dry wt.) -291- Table 7.16 Chemical Composition of Suspended Solids from the River Ecclesbourne - Sampling Occasion 08/78 Cu Pb Zn Cd Fe Mn 352 120 2315 2685 65 42593 7222 318 84 512 904 39 10361 2018 328 168 2475 1782 40 43564 6040 321 176 5135 1892 41 65541 4459 336 105 2288 869 39 31046 2288 325 102 1837 918 61 55102 3673 327 86 1379 724 - 47414 3621 351 121 2069 966 17 54310 2931 Tributary Sites Cu Pb Zn Cd Fe Mn 347 229 4571 5429 171 120000 2571 315 140 1105 977 58 59302 3837 322 87 673 288 96 50000 3462 331 159 664 720 65 47664 3551 Units t ppm (dry vt.) -292- filtrable metal and particulate metal concentrations. Errors involved in the two methods will be added when the results are combined to give the total metal value. Despite this, the precision (expressed by C.V.) for the total metal values is not signif- icantly worse than that for filtrable metal deter- minations (Tables 7.12 and 7.*13), implying that analytical error is not a significant factor in the variation found in total metal concentrations. The variability of the data for heavy metals in water can be related more closely to sampling and analytical error than was possible for sedi- ments. On four occasions, at two sites on each river, four replicate water samples were taken. The sites were chosen to represent anomalous and control sites in each catchment. Using 1-Way ANOVA the variation between replicates can be compared with that between sampling occasions. The results of the analyses are given in Table 7.17. It can be seen from the tables that with three exceptions, for each site on a given occasion the between sample variation is not significant in comparison with the between occasion variations. This means that for studying seasonal variations in metal concen- trations in water the sampling and analytical errors of the methods used are acceptable, and that the variations observed in the data are not just caused by experimental error. A further discussion of -293- Table 7.17 Results of 1-Way ANOVA Performed on Replicated Samples from Minsterley Brook and the River Ecclesbourne 31F F Sig 31T F f Sig Cu 96.843 N .S. Cu 358.994 N .S. Pb 78.060 Pb 2493.43 Zn 1113.88 Zn 777.97 Cd 103.844 Cd 65.809 Fe 107*. 574 Fe 943.69 Mn 56.599 Mn 600.28 02F F Sig 02T F Sig Cu 79.75 N .S. Cu 94.342 N .S. Pb 26.039 Pb 16.639 Zn 723.856 Zn 498.141 Cd 14.094 Cd 21.465 Fe 226.14 Fe 50.734 Mn 121.755 Mn 5.405 P=0.01 318F F Sig 318T F Sig Cu 177.574 N S. Cu 192.762 N.S. Pb 75.261 Pb 15.992 Zn 598.456 Zn 60.347 Cd 42.98 Cd 3.478 P=0.05 Fe 248.015 Fe 19.045 N.S. Mn 199.761 Mn 47.536 1 331F F Sig 331T F Sig Cu 24.179 N. S. Cu 80.934 N 7.714 Pb 467.933 Pb 1 Zn 239.425 .1 Zn 602.187 Cd 5.652 P=0.01 Cd 7.915 ' Fe 77.906 N. S. Fe 119.674 Mn 3199.16 N. s. Mn 611.99 N.S. s Not Significant F s Variance Ratio Sig t Significance -294- Table 7.18 Results of 2-Way ANOVA Performed on Minsterley Water Data Filtrable Cu F Sig Pb F Sig B.S. 3. 179 P < 0.01 B.S.— 16.594 P <0.01 B.O. 11. 623 P <0.01 B.O. 1.949 N.S. Zn F Sig Cd F Sig B.S. 74. 942 P < 0.01 B.S. 34.480 P <0.01 B.O. 3. 259 P <0.05 B.O. 1.827 N.S. Fe F Sig Mn F Sig B.S. 8.338 P <0.01 B.S. 4.809 P <0.01 B.O. 8.418 P <0.01 B.O. 3.752 P <0.01 Ca F Sig Mg F Sig B.S. 38.295 P <0.01 B.S. 95.917 P <0.01 B.O. 5.651 P <0.01 B.O. 16.978 P <0.01 Total Exchangeable Cu F Sig Pb F Sig B.S. 3.020 P <0.01 B.S. 8.789 P <0.01 B.O. 19.662 P <0.01 B.O. 11.883 P <0.01 Zn F Sig Cd F Sig B.S. 73.450 P <0.01 B.S. 29.636 P <0.01 B.O. 1.238 N.S. B.O. 2.533 P <0.05 F Sig Fe F Sig Mn 1 B.S. 4.328 P < 0.01 B.S. 4.303 ] P <0.01 B.O. 18.610 P <0.01 B.O. 18.298 j P <0.01 B.S. t Between Site F t Variance Ratio B.O. i Between Occasion N.S. t Not Significant Sig : Significance -295- Table 7.18 Results of 2-Way ANQVA Performed on River Ecclesbourne Water Data Filtrable — Cu F Sig Pb F Sig B.S. 8 s935 P <0.01 B.S. 2.022 N.S. B.O. 13.007 P <0.01 B.O. 14.358 P <0.01 Zn F Sig Cd F Sig B.S. 86.730 P <0.01 B.S. 1.731 N.S. B.O. 93.949 P <0.01 B.O. 6.189 P <0.01 Fe F Sig Mn F Sig B.S. 1.757 N.S. B.S. 11.129 P <0.01 B.O. 18.313 P <0.01 B.O. 6.380 P <0.01 Ca F Sig Mg F Sig B.S. 17.078 P <0.01 B.S. 5.589 P <0.01 B.O. 5.704 P < 0.01 B.O. 21.511 p <0.01 Total Exchangeable Cu F Sig Pb F Sig B.S. 9.200 P < 0.01 B.S. 3.299 p <0.01 B.O. 4.083 P < 0.01 B.O. 2.829 p <0.05 Zn F Sig Cd F Sig B.S. 9.606 P <0.01 B.S. 3.500 p <0.01 B.O. 12.732 P < 0.01 B.O. 7.520 p <0.01 Fe F Sig Mn F Sig B.S. 1.661 N.S. B.S. 7.317 p <0.01 B.O. 2.528 P < 0.01 B.O. 6.176 p <0.01 B.S. : Between Site Sig i Significance B.O. : Between Occasion N.S. s Not Significant F : Variance Ratio -296- the analytical and sampling errors is given in Section 7.10. A series of 2-Way ANOVAs were performed on the water data, the results being given in Tables 7.18 and 7.19. The F-values for the total and filtrable data from Minsterley Brook are significant for bet- ween site variation and between.occasion variation, with the exception of filtrable Pb and Cd and total Zn. The Ecclesbourne data show similar features in that between occasion variation is significant for all the elements. Filtrable Pb, Cd, Fe and total Fe show no signif- icant variation between sites as might be expected from the dispersion plots. The inference from these results is that for a study concerned with examining trace heavy metals in river water, seasonal fluc- tuations in metal concentrations must be considered. 7.4. Seasonal Variations in Geochemical Data 7.4.1.Stream Sediments Two sites were selected from each river to examine seasonal variations in sediment data. The sites were chosen to represent contaminated and control environments respectively, and were sites 31 and 134 on Minsterley Brook and sites 318 and 327 on the River Ecclesbourne. Sites 134 and 327 are also the locations of permanent flow measuring dev- ices operated by the Severn Trent Water Authority who have kindly provided data from them. -297- The data for site 31 and 134 are plotted against time in Figure 7.19A. At site 31, there is a general trend for winter (Feb., Dec.) peaks in concentration for Cu, Pb, Zn, Cd and Ca with a minimum in concen- tration occurring in June. Fe and Mg, however, have minimum concentrations in December and there is a steady increase in concentration throughout the year. At site 134, Ca, Mn and Cd follow similar general trends with a gradual increase in concentra- tion through the year. For Ca and Cd this is the reverse of the pattern at site 31. At both sites there is a general tendency towards an early summer (April, June) minimum in concentration, but with the exceptions of Cd at both sites and Fe and Mn at site 31. River flow is a variable that is thought to have an influence on stream sediment composition. Two measures of flow have been used; the mean flow on the day of sampling and the mean daily flow for the two months preceeding the sampling. This esti- mate was chosen as it is representative of river conditions influencing stream sediment composition during the period between samples. The flow data is plotted in Figure 7.21. To quantify relation- ships between flow and concentration at each site correlation coefficients were determined and are presented in Table 7.20. The flow data from site 134 will only give an estimate of the relative -298- Site 31 2000 J0000 50000 400 Cu Pb Zn Cd concn ppm ppm D F A J AuO 20000 D FAJAuO DFAJA-0 DFAJ AuO 30000 500Q 20. 2000 Fe Mn Co Mg r— % concn ppm ppm ppm D 3000 1000 10000 D F A J Au 0 wuu D F A J A. 0 DFAJ Aw 0 D F A J A» 0 Site 134 800 800' Cu Pb Zn Cd concn ppm ppm ppm 400 600l DFAJAuO DFAJ A-0 DFAJ AuO D F A J A« 0 ^4000 2000 10000 4000 Fe Mn Co Mg concn ppm 20000 2000 DFAJ AuO DFAJ A-0 D F A J A- 0 D F A J A- 0 Key: 0=0ctober, D=December, F=February, A=April, J=June, Au=August. Figure 7.19A Variations in Metal Concentrations in Stream Sediments vith Time - Minsterley Brook -299- Site 318 100 50000 3000 Cu Pb Zn Cd concn ppm ppm ppm SOL • m 1000 20 '0 D F A J A* ODFAJA* ODFAJA- 0 D F A J A»j 30000 1000, 1Q 3000 Fe Mn Co Mg — % concn ppm ppm 20000 ZD 600 • 2000 ODFAJAu ODFAJAu 0 D F A J A« ODFAJA- Site 327 30 1000 Cu .Pb Zn Cd concn ppm ppm ppm 20 600 200 ODFAJA- ODFAJAu ODFAJA- 0 D F A J A, 30000 2000 Fe Mn CQ Mg concn ppm 10000 500 ODFAJA- ODFAJA- iDO°0 DFAJA- ODFAJA Keys 0=0ctober, D=December, F=February, A=April, J=June, Au=August. Figure 7.19B Variations in Metal Concentrations in Stream Sediments with Time - River Ecclesbourne Correlations of Concentration of Metals in Stream Sediments with River Flow Table 7.20 - Minsterley Brook Site 31 Cu Pb Zn Cd Fe Mn Ca Mg Daily Flow .962*** .789** .861** .974*** -.666 .417 .848** -.997*** 2. PWHv Flow .818* .583 .690* .895*** -.783** .561 .937*** -.925*** Site 134 Daily Flow -.020 .923*** -.002 .810** -.107 .626 -.641 .675* X WoaHN FUva -.140 .799** -.106 .694* -.193 .803** -.741* .779** Correlation of Concentration of Metals in Stream Sediments with River Flow. Table 7.21 River Ecclesbourne Site 318 Daily Flow -.026 .674 .445 .544 -.083 .454 Z Flow -.559 .462 .076 .628 -.107 -.065 Site 327 Daily Flow -.614 .542 .734* -.737* -.661 .691* -.057 -.561 ZWca+K Flow -.683* .719* .816** -.734* -.656 .820** -.816** -.572 -301- variation in flow between different occasions at site 31. However, for a catchment of this size it is considered that the data can be used in this manner and that the river flow measured at site 134 will represent conditions at site 31. From both the plots and Table 7.20, the concentrations of several elements are quite highly correlated with river flow. From this it is reasonable to suggest that the behaviour of several metals is quite closely related to river flow conditions, both antecedent and at the time of sampling. Cu, Zn, Cd and Ca are significantly correlated with flow at site 31. At site 134, however, the relationship between con- centration and flow either becomes non-significant or negatively significant. At site 31, this result is thought to reflect the erosion into the river and transport of mine waste and contaminated bank material containing sulphide minerals from the area surrounding Gravels mine. This process may dominate over the action of winnowing of fine grained metal rich material at high flows. Thus metals would tend to accumulate at high flows particularly if they were present as heavy sulphide mineral grains. At site 134, about 24 km from Gravels, the influence of the mine dump as a source of sediment is prob- ably much diminished. Thus the removal of fine grained particles, for example, clays and Fe/Mn oxides containing heavy metals, may occur at high flows. Such a process would explain the negative -302- correlations of metals such as Cd and Mn with river flow. The negative correlation of Fe with flow at site 31 and the plot for Fe for site 134 (except for February) suggest that the winnowing process may be important in controlling Fe concentrations in the sediments. The high concentrations of Fe, Mg and Cu in sediments at site 134 on the February sampling occasion may be related to the very high river flow which occurred at this time (Figure 7.2lf\) . Erosion of river banks, for example, may have intro- duced large quantities of material directly into the stream causing the concentrations of these metals in the sediments to be increased. For the River Ecclesbourne, the plots of sedi- ment concentration against time are shown in Figure 7.19B. With the exception of Ca and Mg at site 318, all metals tend to exhibit low concentrations during the winter months (December and February) . At site 327 there is also a trend for peak metal levels to occur in autumn (October) and the summer months (June and August). Although several metals also follow a similar trend at site 318, the behaviour of individual metals is not so uniform. Relationships between river flow and concen- tration have been examined in a similar manner to Minsterley Brook and correlation coefficients are -303- given in Table 7.21. River flow is plotted in Figure 7.21. A general inverse relationship between flow and concentration is evident particularly at site 327, though it is only weakly developed at site 318 for a few elements. At site 327 the correlation coefficients are generally higher for the two monthly- mean daily flows. This suggests that the river con- ditions for the period between sampling occasions may be a more important control on sediment chemistry than those at the time of sampling. This comment applies only to a few metals at the Minsterley Brook sites. That a reverse relationship exists probably suggests that the mechanism of removal of fine grained material during high river flows is operating. The poor relationships at site 318 clearly suggest that other processes are more important in causing seas- onal variations. The extent, for example, of the influence of the building works at the Wirksworth sewage works on the trace element composition of the sediment is largely unknown. Additionally var- iation in the input of trace metals from sewage effluent is not fully known for this period (see Section 7.4.2). Two significant and related environmental fac- tors which could also influence seasonal variations in sediment heavy metal concentrations are river temperature and biological activity. Biological activity involving the accumulation of metals in -304- sediments by micro-organisms and the removal of metals from the water column by plants and macro- organisms will clearly influence seasonal variations in trace metal concentrations. This activity it- self will be constrained by variations in the nu- trient status of the stream and by fluctuations in river temperature and dissolved oxygen concentra- tion. Although no measurement was made of "biolo- gical activity" during this project, the increase in sediment concentration of many metals during the spring/summer months might be ascribed to a possible increase in the activity of micro-organisms in the sediments. This may cause an increase in metal concentration either by direct uptake in the organism itself or by indirect involvement of the organism with precipitation/adsorption reactions (Carpenter and Hayes 1978). The death of annual aquatic plants in the autumn (October-November) may also release heavy metals accumulated during the growing season to the water column. These may be taken up by sediments and be responsible, in part, for the high sediment levels of many metals in the October samples. Accordingly low concentrations of metals in sediments in winter months may be re- lated to low biological activity during these months. 7.4.2.Filtrable Stream Water Data River Ecclesbourne For the heavy metals apart from Cu, there is -305- a general trend of a decrease in concentration to- wards the summer months from autumn and winter high levels, although detailed exceptions do occur (Figure 7.20A). This pattern may reflect an increase in the uptake of metals by the biota during the growing season with death, decay and subsequent release of mfetals during autumn and winter. The major cations follow no general trends, although levels of Mg at site 3X8 tend to increase throughout the year (Figures 7.20A). Mg is the only element at site 327 to correlate with river flow on the day of sampling (see Table 7.37 and Section 7.9). River flow may be a controlling factor in the behaviour of this metal. Unfortunately, there is no data for two of the sampling occasions for the sewage works effluent. This makes the impact of this effluent on the sol- uble metal chemistry difficult to interpret. The data for the effluent have been plotted however (Figure 7.22) and for Cu, Pb and Zn there are simi- larities between these plots and the plots for site 318. It is probable* that variations in effluent quality may influence the variation in the concen- trations of Cu, Pb, and Zn in the recieving waters. The quantity of effluent discharged in relation to the amount of river flow also has to be considered. Minsterley Brook Trends for the two sites are different for -306- Site 318 to Cu Pb Zn Cd concn ppb ppb ppb ppb n ixb o , 0 D F A J A» ODFAJAa 0 D F A J A* ODFAJA* 100 Fe Mn Co Mg concn ppb ppb m . 0 0 F A J A« 0 DFAJ A«. ODFAJAw ODFAJA-. Site 327 100 Cu Pb Zn Cd concn ppb ppb ppb ppb EEh . ODFAJA. ODFAJA- ODFAJA-. ODFAJA- 100 70 Fe Mn Ca Mg concn ppb ppb Ld ODFAJA- ODFAJA- ODFAJAu ODFAJA. Keys 0October, D=December, F=February, A=April, J=June, Au=August. Figure 7.20A Variations in Filtrable Metal Concentrations vith Time - River Ecclesbourne -307- Site 31 6 7S 2000 20 Cu Pb Zn Cd ppb ppb ppb ppb • 25 PFAJA-0 DFAJA.0 DFAJAuO DFAJ A«0 80 6q 200 Fe Mn Co Mg concn ppb ppb J 20 DFAJAuO DFAJA.0 DFAJ A-0 DFAJAuO Site 134 100 Cu [—I Zn Cd Pb ppb ppb ppb ppb 60 1 . DFAJ AvO DFAJA-0 DFAJ A- 0 DFAJ A-0 50 100 o u 200 Fe Mn Ca Mg concn ppb ppb • • 60 DFAJ A- O DFAJA-0 DFAJA-0 DFAJA-0 Keyx 0=0ctober, D=December, F=February, A=April, J=June, Au=August. Figure 7.20B Variations in Filtrable Metal Concentrations with Time - Minsterley Brook -308- 300 300 B River Row Ml/day Ml/day DFAJ Ah 0 DFAJ AuO Minsterley Brook site 134 200 200 River Flow Ml/day Ml/day ODFAJA* ODFAJAu River Ecclesbourne site 327 Key: 0=0ctober, D=December, F=February, A=April, J=June, Au=August. Figure 7.21 Variations in Mean River Flow with Time A \ Mean River Flow on Day of Sampling C ) B > Mean Daily River Flow During Two Month Sampling D ) AA,=C11 J Interval. Key: 0=0ctober, D=December, F=February, A=April, J=June, Au=August. Figure 7.22 Filtrable Metal Concentrations in Effluent from Wirksworth Water Reclamation Works. -310- many of the metals (Figure 7.20B). Levels of Ca • and Mg, however, tend to rise at both sites through the year from December. Unlike the Ecclesbourne, Mg concentrations at site 134 are not correlated with river flow on the day of sampling. Zn and Cd tend to follow Ca and Mg at site 31. The levels of Fe and Mn at site 134 are positively correlated with river flow (see Table 7.36 and Section 7.9). Apart from the patterns mentioned above, trends common to a number of elements cannot be recognised. This apparent scatter in the data is thought to occur because the sampling interval may be too long. It is possible that significant changes in stream water chemistry may happen in response to climatic/ biological processes occurring on a shorter time scale than two months. These short term variations may mask seasonal patterns when a relatively long time interval occurs between samples (see Sections 2.1.1 and 2.2.1). The data probably give an ade- quate estimate of the range of concentrations that may be expected, however. They also point to the unreliability of using single annual or biannual water samples to represent the dissolved metal status of a river. 7.5 Relationships between Sample Types The relationship of stream sediment geochemical data to water quality and its use as a predictive -311- tool has been discussed on a number of occasions (e.g. Aston and Thornton 1977, Webb 1973). To investigate this relationship for the data from Hinsterley Brook and the Ecclesbourne, correl- ation 'matrices, interelating sample types, were computed for each element. The correlation matrices were prepared using the statistical computer package GENSTAT V, Mark 4.02 on line to ITE Bangor from Cambridge University. Log transformed data for all six occasions were combined for sites 129-134 on Minsterley Brook and sites 352-351 on the Ecclesbourne. The results are given in Tables 7.22 and 7.23. Sev- eral of the significant correlations obtained would be anticipated from the nature of the samples. Thus nitric attack and 0.5M HC1 leach data correlate sig- nificantly for all elements, as do total and fil- trable heavy metals". The latter two sets of results are not strictly independent, however, as the fil- trable metal data are an element in the calculation of the total metal concentrations. Significant correlations are found between sediment concentrations (HNO^ and HC1) and water metal concentrations, (filtrable and total) for Pb, Zn, and Cd in Minsterley Brook and for Zn in the Ecclesbourne. The correlations are not maintained for Pb and Cd in the Ecclesbourne, however. Sedi- ment water relationships for Cu, Fe, and Mn are poor in both catchments, with few statistically Table 7.22 Correlations Between Sample Types - Minsterley Brook Nit Hcl 1.0000 0.7931* 1.0000 0.4119* 0.2965 1.0000 0.3365* 0.1557 0.9447* 1.0000 0.3209 0.6164* 0.0104 •0.0918 1.0000 Nit Hcl P 1.0000 0.9435* 1.0000 0.7197* 0.7487* 1.0000 i 0.5796* 0.5165* 0.8500* 1.0000 »-L»J 0.7822* 0.7742* to 0.7652* 0.5647* 1.0000 i Nit Hcl 1.0000 0.9339* 1.0000 0.8289* 0.8956* 1.0000 0.8283* 0.8835* 0.9749* 1.0000 0.8249* 0.9097* 0.8570* 0.8102* 1.0000 Nit Hcl P 1.0000 0.9283* 1.0000 0.8727* 0.8573* 1.0000 0.8411* 0.8634* 0.9421* 1.0000 0.7477* 0.8355* 0.7223* 0.6750* 1.0000 Table 7.22 (contd.) Fe Nit Hcl Nit 1.0000 Hcl 0.6723* 1.0000 F -0.5399* -0.2579 1.0000 T -0.3943* -0.3488 0.6841* 1.0000 P -0.5123* -0.4290* 0.0094 0.0896 1.0000 Mn Nit Hcl P Nit 1.0000 Hcl 0.9711* 1.0000 F 0.4315* 0.4807* 1.0000 T 0.1898 0.1829 0.5864* 1.0000 P -0.1206 -0.2784 •0.1302 0.2319 1.0000 i »-u>» Ca Nit Hcl u> Nit 1.0000 I Hcl 0.9219* 1.0000 F -0.7741* -0.7672* 1.0000 Mg Nit Hcl F Nit 1.0000 Hcl 0.5192* 1.0000 F 0.3663* 0.1511 1.0000 Nit Nitric attack ) -sediments Hcl 0.5M Hcl leach) F Filtrable metal ) T Total exchangeable metal) -water P Particulate metal ) Denotes significant correlation at p = 0.01 Table 7.23 Correlation Between Sample Types - River Ecclesbourne Cu N F H N 1.0000 F 0.3636 1.0000 T 0.4657* 0.8449* 1.0000 P 0.2779 0.7005* 0.7188* 1.0000 H 0.9407 0.1228 0.1980 0.0661 1.0000 Pb N F H N 1.0000 F 0.1918 1.0000 T 0.4077* 0.6032* 1.0000 P 0.0950 0.3417 0.4522* 1.0000 i H 0.9801* 0.3306 0.6151* -.1773 1.0000 W Zn N F H N 1.0000 i F 0.5222* 1.0000 T 0.5876* 0.8524* 1.0000 P 0.5587* 0.5047* 0.3591 1.0000 H 0.9533* 0.8473* 0.6150* 0.6346* 1.0000 Cd N F H N 1.0000 F 0.3232 1.0000 T 0.3851 0.7449* 1.0000 P 0.3114 0.0747 0.2785 H 0.9529* 0.1839 0.4648* 0.3228 1.0000 Table 7.23 (contd.) Fe N H N 1.0000 F 0.1890 1.0000 T 0.0390 0.4183* 1.0000 P 0.2036 0.0252 0.2077 1.0000 H 0.5236* -.0445 0.0718 0.4102* 1.0000 Mn N H N 1.0000 F -0.2589 1.0000 T -.2011 0.6494* 1.0000 P 0.1221 •0.1041 0.3150 1.0000 H 0.5605* -.0252 •0.1709 0.5294* 1.0000 Ca N H N 1.0000 F 0.6872* 1.0000 H 0.9816* 0.8378* 1.0000 Mg N F H N 1.0000 F -0.2387 1.0000 H 0.9172* -.4691* 1.0000 N Nitric attack ) -sediments H 0.5M Hcl leach) F filtrable metal ) T total exchangeable) waters P particulate metal ) * - denotes significant correlation at p = 0.01 -316- significant correlations and none of these greater than 0.5000. Iron in the sediments (HN03 attack) is significantly negatively correlated with fil- trable Fe in Minsterley Brook (r = -0.5399). Rela- tionships between sediment Ca and filtrable Ca are very different in the two rivers. In Minsterley Brook, the two are strongly negatively correlated, (r = -0.7741, Nit/F, and r = -0.7672, HCl/F), as might be expected from the shapes of the mean dispersion plots for nitric attack and filtrable Ca. A positive correlation (r = 0.6872, Nit/F, and r = 0.8378, HCl/F) exists for the Ecclesbourne data. Correlations for Mg are also poor and inconclusive. For a particular river, the relationships out- lined above suggest that stream sediment data only provide a means of predicting water quality crit- eria for pollutant elements with point sources and well defined and similar concentration decay curves, as for Pb, Zn and Cd in Minsterley Brook and Zn in the River Ecclesbourne. These elements are present at contaminated sites in concentrations which cont- rast highly with background levels in both the water and sediment phases. All these factors appear to be important in determining the reliability of correlations between element concentrations in water and sediments in a particular river system. The relationship between the composition of stream sediment and suspended solids can be examined -317- using the correlations between particulate data and sediment data (HN03 and HC1) in Tables 7.22 and 7.23. For Minsterley Brook levels of Cu, Pb, Zn and Cd in suspended solids correlate with those found in both sediment phases. Fe has a negative correlation and there is no correlation between the phases for Mn. These results could indicate that Cu, Pb, Zn and Cd in suspended solids are derived from clastic erosion of contaminated bank material whose chemistry re- flects that of the stream sediments. The result for Mn reflects different behaviour suggesting that its chemistry in the suspended solids phase may be controlled by dissolution/precipitation reactions. The negative correlation for Fe, although not highly statistically significant, may indicate that resus- pension of fine grained bed sediment, perhaps during high river flow, is a dominant control. This would cause a drop in the levels of Fe in the sediments reflected by a rise in the Fe concentration in the suspended solids. The results for the River Ecclesbourne contrast with those for Minsterley Brook. With the exception of Zn, no correlations occur between metals in sus- pended solids and stream sediments for the HNO^ attack. Positive correlations occur for Zn, Cd, Fe and Mn between suspended solids and the non- residual sediment phase (HCl). The difference bet- ween the results for the two rivers is thought to be related to the different sources for heavy metals in -318- the two catchments. That is, predominantly in sol- ution in the Ecclesbourne and both in solution and by the clastic erosion of mine waste/contaminated bank materials in Minsterley Brook. Thus in the Ecclesbourne the chemistry of metals in the suspen- ded solids and stream sediments may be dominated by adsorption/precipitation reactions (see Section 7.7) and hence correlations with the non-residual phase in the sediments. In Minsterley Brook, how- ever, the significant correlations between suspen- ded solids and both the HC1 and the HNO^ sediment data, suggest that clastic erosion (in addition to chemical reactions) may be an important process controlling the heavy metal composition of suspen- ded solids. Tables 7.24 and 7.25 give proportions of fil- trable to non-filtrable heavy metals in the catch- ments. These data were derived from the mean con- centrations for the yearly period. The proportion is simply the evaluation ofJ Mean Total Exchangeable - Filtrable 100% Total Exchangeable 1 The similarity in the data for Cu, Pb, Zn and Cd both between the two rivers and amongst sample sites within the rivers is striking. The high input of dissolved metals from the mine site at Gravels is reflected in the high percentage of filtrable metals at site 33, (Cu 79%; Zn 91%, Cd 90%). The percentages decrease away from this site implying -319- Table. 7.24 Mean Percentage Filtrable Heavy Metals - Minsterley Brook Site Cu Pb Zn Cd Fe Mn 129 77 29 59 68 37 38 33 79 32 91 90 36 55 31 67 33 89 81 36 75 30 64 26 86 85 34 66 28 63 19 78 70 40 49 107 60 15 77 69 29 30 10 70 23 80 62 31 44 9 67 19 62 58 22 46 3 76 26 75 38 14 44 126 76 35 77 63 28 46 134 83 47 77 44 32 48 Mean 71 28 77 66 31 49 Tributary Sites Cu Pb Zn Cd Fe Mn 02 70 43 52 71 33 36 105 67 44 65 50 39 55 29 68 18 56 50 27 25 132 69 53 20 57 26 44 Mean 69 40 48 57 31 40 -320- Table 7.25 Mean Percentage Filtrable Heavy Metals - River Ecclesbourne Site Cu Pb Zn Cd Fe- Mn 352 65 33 76 58 28 74 318 57 24 73 71 28 63 328 63 28 60 56 21 45 321 70 18 74 65 20 53 336 74 26 73 67 23 48 325 80 27 59 64 27 43 327 86 38 81 70 38 54 351 68 20 64 54 23 39 Mean 70 27 70 63 25 52 Tributary Sites Cu Pb Zn Cd Fe Mn 322 71 48 96 112 32 32 331 67 40 67 53 44 55 Mean 69 44 82 83 38 44 -321- a transfer of metals to particulate matter as the pH increases. Processes of adsorption and mineral precipitation are probably responsible for this. The percentages of filtrable Fe and Mn are reason- ably constant for both rivers at all the sites. Pb and Fe tend to be predominantly associated with the particulate phase in both rivef-s. Approximately 75% of the total exchangeable Pb is associated with the particulate phase and about 70% of the Fe. Yates (1978) and Whiting (1979) noted a similar association for Pb with particulate matter in rivers of south west England, although these are "soft water" systems. The percentage of filtrable Pb tends to be higher at the highly contaminated sites 33 and 31, and this may be due to the input of dissolved metal at these sites. The percentages are again elevated at the background sites 02, 132 and 134 where the amounts of Pb present associated with the particulate phase are very low indeed, and close to the detection limit of the method. 7. 6 Interelement Correlations Relationships between individual elements were investigated by "least squares" regression analysis utilising the GENSTAT computer package. Combined data for all six occasions were used for sites 33-134 Minsterley Brook and similarly combined data for sites 352-351 were used for the River Ecclesboume. The data were amalgamated in this manner in order -322- to produce more reliable statistics using a larger data set. Site 129 on Minsterley Brook and tribu- tary sites for both rivers were omitted from the data analysis as the purpose was to investigate fac- tors controlling the dispersion of metals downstream from the pollution sources. Site 352 was chosen as the upper site on the Ecclesbourne. Upstream of this site, the river is divided into two tributaries. These both carry contaminated water into the main river and may be regarded together as a pollutant "source". The western limb receives drainage from the mining area to the west of Wirksworth, and the eastern one drainage from the town itself and prob- ably three mine adits. Interelement correlations were determined for all elements for nitric acid attack and 0.5M HC1 leach data for sediments, filtrable water data, total exchangeable metal data and dry weight part- iculate data. The statistics were computed on log transformed data in order to overcome the inherent bias in the distribution of the data. (Chork 1979, pers. comm., Moss 1980, pers. comm.). The correl- ation matrices obtained, giving values of the cor- relation coefficient 1 r', are contained in Tables 7.26 and 7.27. Significant correlations at p=0.05 are marked *. In addition, between element correl- ations were calculated for the HNO^ - HCIO^ data obtained for occasion 10/78 for Minsterley Brook and 06/78 for the Ecclesbourne (Table 7.28). Table 7.26 Interelement Correlations for Minsterley Seasonal Data Nitric Acid Attack d.f. = 60 Cu Pb Zn Cd Fe Mn Ca Mg 1.0000 0.9646* 1.0000 0.9661* 0.9803* 1.0000 0.9672* 0.9654* 0.9825* 1.0000 •0.1638 -0.1613 •0.1840 •0.1656 1.0000 0.8534* 0.8646* 0.8884* 0.8893* -0.2684 1.0000 0.9104* 0.9150* 0.9343* 0.9338* 0.8515* 1.0000 -0.5746* -0.6108* •0.5830* -0.5452* •0.5523* 0.7429* •0.7632* •0.6594* 1.0000 0.5M Hcl leach d.f. * 46 i OJ Cu Pb Zn Cd Fe Mn Ca Mg to 1.0000 u> I 0.8750* 1.0000 0.9049* 0.8811* 1.0000 0.9017* 0.8647* 0.9817* 1.0000 0.1507 •0.0851 0.0277 0.0437 1.0000 0.8555* 0.8713* 0.8348* 0.8333* -0.0669 1.0000 0.7915* 0.9029* 0.8943* -0.3511 0.8734* 1.0000 •0.2071 0.8812* •0.2885 •0.1522 •0.1447 0.5600* •0.4492* •0.3237 1.0000 Table 7.26 (contd.) Filtrable Metals d.f. e 61 Cu Pb Zn Cd Fe Mn Ca Mg pH 1.0000 0.7279* 1.0000 0.3305 0.7656* 1.0000 0.4346* 0.8053* 0.9387* 1.0000 0.6689* 0.5335* 0.1778 0.2833 1.0000 0.3834 0.4245* 0.1699 0.2821 0.3843 1.0000 -0.3238 -0.3115 •0.1248 -0.3320 -0.5444* •0.1647 1.0000 -0.4306* -0.5948* -0.4734* -0.6164* -0.4605* -0.1928 0.8378* 1.0000 -.5405* -.5616* -.4836* -.6470* -.5886* -.5352* 0.6632* 0.6766* 1.0000 Total Exchangeable Metals d.f. 52 i u> Cu Pb Zn Cd Fe Mn to 1.0000 I 0.9242* 1.0000 0.4560* 0.6660* 1.0000 0.5365* 0.7042* 0.9266* 1.0000 0.7825* 0.6376* -0.0202 0.0515 1.0000 0.6871* 0.5752* 0.0035 0.1118 0.8634* 1.0000 Particulate Heavy Metals d.f. = 34 Cu Pb Zn Cd | Fe Mn 1.0000 0.7646* 1.0000 0.7897* 0.8481* 1.0000 0.8109* 0.7674* 0.9094* 1.0000 0.3208 0.0194 0.0607 0.0482 1.0000 -.2733 -0.5173* •0.5081* •0.4790* 0.6645* 1.0000 Significant Correlations are Marked* Table 7.27 Interelement Correlations for River Ecclesbourne Seasonal Data Nitric Acid Attack d.f. 42 Cu Pb Zn Cd Fe Mn Ca Mg 1.0000 0.5752* 1.0000 0.8701* 0.8421* 1.0000 0.8602* 0.8337* 0.9807* 1.0000 0.3245 -0.2810 0.0036 0.0023 1.0000 0.0809 -0.3779 •0.1969 •0.1903 0.7431* 1.0000 0.8338* 0.8156* 0.9352* 0.9344* -0.0964 •0.3078 1.0000 0.9459* 0.6117* 0.8984* 0.8905* 0.2143 •0.0700 0.8838* 1.0000 Filtrable Metals d.f. > 44 l U> Cu Pb Zn Cd Fe Mn Ca Mg pH to 1.0000 Ln 1i I 0.5792* 1.0000 0.2856 0.2851 1.0000 1 I 0.4184* 0.4561* 0.6578* 1.0000 0.5077* 0.6399* 0.1886 0.1969 1.0000 -0.0379 0.1208 0.6338* 0.3304 -0.0067 1 .0000 0.3557 0.3204 0.2833 0.1467 0.4173* 0 .3832 1 .0000 0.0386 0.0211 -0.6742* -0.5023* 0.2070 -0 .4906* 0 .0151 1 .0000 -0.1524 -0.2656 -0.4995* -0.4682* 0.0746 -0 .5122* 0 .1757 0 .4280* 1.0000 Total Exchangeable Metals d.f. c 44 Cu Pb Zn Cd Fe Mn 1.0000 0.4688* 1.0000 0.4944* 0.5469* 1.0000 0.4897* 0.5728* 0.7491* 1.0000 0.2283 0.6050* 0.0858 0.0358 1.0000 0.3195 0.3739 0.6812* 0.4691* 0.3459 1 .0000 Table 7.27 (contd.) Particulate Metals d.f. e 26 Cu Pb Zn Cd Fe Mn Cu 1.0000 Pb 0.1842 1.0000 Zn 0.6035* 0.2422 1.0000 Cd 0.4055* 0.0219 0.7220* 1.0000 Fe 0.1374 0.5347* 0.2717 0.2114 1.0000 Mn 0.5232* 0.0906 0.7228* 0.6127* 0.5674* 1.0000 0.5M Hcl Leach d.f. 14 Cu Pb Zn Cd Fe Mn Ca Mg Cu 1.0000 i u> Pb 0.5911* 1.0000 NJ Zn 0.7792* 0.9248* 1.0000 I Cd 0.8189* 0.9047* 0.9925* 1.0000 Fe 0.4377 0.0540 0.2989 0.2837 1.0000 Mn -0.0422 -0.5650* -0.3916 -0.3888 0.6795* 1.0000 Ca 0.8831* 0.8046* 0.8980* 0.9321* •0.3529, 1.0000 Mg 0.2106 0.9169* 0.5483* 0.7578* 0.7965* 0.4754 0.0371 0.8772* 1.0000 Significant correlations are marked * Table 7.28 Interelement Correlations for Nitric-Perchloric Attack Data Minsterley Brook d.f. 10 10/78/ Cu Pb Zn Cd Fe Mn Ca Mg Cu 1.0000 Pb 0.9761* 1.0000 • Zn 0.9806* 0.9890* 1 .0000 Cd 0.9831* 0.9834* 0 .9959* 1 .0000 Fe 0.8337* 0.8090* 0 .8138* 0 .7980* 1 .0000 Mn 0.6917* 0.6930* 0 .7140* 0 .6610* 0 .7880 1 .0000 Ca 0.9791* 0.9901* 0 .9993* 0 .9962* 0 .8096* 0 .6982* 1 .0000 Mg 0.6569* 0.6589* 0 .6804* 0 .6480* 0 .6005* 0 .8031* 0 .6738* 1.0000 River Ecclesbourne d.f. = i 06/78 Cu Pb w Zn Cd Fe Mn Ca Mg to Cu 1.0000 Pb 0.5756 1.0000 Zn 0.8458* 0.9085* 1 .0000 Cd 0.8759* 0.8690* 0 .9893* 1 .0000 Fe 0.1542 0.3423 0 .1450 0 .1864 1 .0000 Mn 0.2129 0.5957 0 .5109 0 .5550 0 .8943* 1 .0000* Ca 0.9067* 0.6700* 0 .8700* 0 .9305* 0 .1879 0 .5210 1 .0000 Mg 0.8551* 0.2056 0 .5288 0 .5580 0 .6001 0 .2797 0 .6359* 1.0000 Significant Correlations are Marked * -328- The correlation matrices give valuable insights into processes controlling the chemistry of the heavy metals. The correlations are compiled from data sets which differ in size, and hence degrees of freedom. This has to be considered when the data are inter- preted as it affects the values of r for which cor- relations are significant. For example, at p=0.05 and for 10 degrees of freedom a value of r=0.5760 is significant, whereas a value of r=0.3809 is sig- nificant for 25 degrees of freedom. Several points can be madeJ i) Highly significant correlations exist between the elements Cu, Pb, Zn, Cd and Mn in sediments for both the HN03 attack and 0.5M HC1 leach for Minsterley Brook. There are no signifi- cant correlations between these elements and Fe. These results reflect the coincident dis- tribution patterns of Cu, Pb, Zn, Cd and Mn in the sediments (see Figures 7.7 and 7.8). Fe, however, follows a different pattern (Figure 7.8). This suggests that Mn oxides may exert considerable control over the chem- istry and distribution of the available or non-residual phases of Cu, Pb, Zn and Cd in these sediments by processes such as adsorp- tion and co-precipitation, but that iron ox- ides are probably not so important ,in this scavenging process in this instance. -329- ii) The HN03 - data for Minsterley Brook show significant correlations for all six heavy metals. These data give the total metal concentrations which will include organic mat- erial and minerals resistant to the other at- tacks. These results indicate the similar behaviour of Cu, Pb, Zn and Cd in this phase, and in contrast to the above suggest that Fe and Mn may both be important in controlling the metal distributions. The contradictory evidence suggested by these correlations and those in i) above reflect the difference in the chemical attacks used. It is probable that the HNO^ attack and the 0.5M HC1 leach did not completely dissolve aged Fe oxide precipitates present in the sediments, thus giving an underestimate of the influence of Fe on the geochemistry of the other elements. iii) For the River Ecclesbourne, Cu, Pb, Zn and Cd correlate significantly in all three sets of sediment data, except that Cu vs Pb correla- tions are not significant for nitric and nitric- perchloric data. Few significant correlations occur with Fe and Mn, although these elements correlate significantly with each other. It would thus appear that although Cu, Pb, Zn and Cd behave similarly in the sediment of this river system, Fe and Mn oxides may not be im- -330- portant in controlling the trace element geo- chemistry. v) Highly significant correlations are found for Cu, Pb, Zn and Cd with Ca in the sediments of both the Ecclesbourne and Minsterley Brook. These correlations reflect the similarity in the shape of the dispersion curves for the heavy metals and Ca. This in turn is probably related to the physical dispersion in the sedi- ments of calcite grains and sulphide mineral particles derived from the dump at Gravels. v) The most important correlations relating to processes amongst the filtrable water data are those with pH. All six heavy metals are sig- nificantly negatively correlated with pH in Minsterley Brook, but only the correlations (negative) with Zn, Cd, and Mn are significant for the Ecclesboume. Correlations Ca vs pH and Mg vs pH are significant and positive for Minsterley Brook although only Mg is correlated significantly (positive) with pH in the Eccles- bourne. These results indicate the importance of pH in controlling the solubility of heavy metals in stream water through processes of hydrolysis and the precipitation of insoluble salts. In view of the large amounts of car- bonate available in both rivers, it is likely that carbonates are an important control on -331- metal solubility at the neutral to alkaline pH's encountered. In nearly all the water samples taken, apart from mine adits and occas- ional samples from sites 129, 33 and 31, the pH' required for hydrolysis of Cu, Pb, Zn and Cd are exceeded. Eh - pH diagrams given by Garrels and Christ (1965) 'for Cu, Zn and Pb also indicate that oxides, hydroxides and car- bonates tend to limit metal solubilities at pH >7.0 in typical river systems. vi) Correlations between Cu, Pb, Zn and Cd in the particulate phases of both rivers are positive and significant. For Minsterley Brook signi- ficant negative correlations occur between these metals and Mn and no significant corr- elations occur with Fe except for Mn vs Fe. These results are difficult to interpret without more detailed study, but they certainly imply that particulate organic material and suspended clay sized particles, rather than Mn and Fe oxides may exert control over Cu, Zn and Cd. 7.7 Partitioning of Heavy Metals in Stream Sediments The ratio of the results for the 0.5M HC1 leach to those of. the HNO^ - HCIO^ attack were calculated for the data for 10/78 Minsterley Brook and 06/78, River Ecclesbourne. The ratios have been expressed as percentages, assuming that the HN0_ - HC10. attack -332- gives the total metal concentration of the sedi- ments. The ratios are thus the proportions of non- residual heavy metals in the sediments. (Agemian and Chau 1976). The results are given in Tables 7.29 and 7.30. A number of results of greater than 100% were obtained. This is due to the errors in both of the methods which are additive when ratios of this sort are calculated. The two chemical at- tacks were performed on separate subsamples rather than sequentially on the same sample of material. Clearly had the latter method been adopted, the results would never exceed 100%. Data for Ca are not given as the ratio is greater than 100% in all cases. Table 7.31 shows the results of analyses of heavy minerals separated from the Minsterley sedi- ments (10/78). The figures are given as ppm dry weight of the heavy mineral constituent, not as the dry weight of sediment sample. The non-residual fraction of the heavy metals represents metals adsorbed to Fe and Mn oxide coa- tings, on clay exchange sites, easily solubilised mineral precipitates and organic exchange complexes. (Agema m and Chau 1976) . It thus also gives a measure of the pool of more readily available heavy metals in the sediment (Malo 1977). The data for Cu, Pb, Zn, and Cd from Minsterley show a gradual increase in the proportion of non-residual metals from the -333- Table 7.29 Proportions of Non-Residual Heavy Metals in Minsterley Sediments Site Cu Pb Zn Cd Fe Mn Mg 129 27 59 31 40 14 56 7 33 2 15 18 19 19 77 27 31 6 73 21 27 13 101 9 30 9 93 36 39 14 87 10 28 8 88 50 55 9 89 7 107 17 116 63 61 9 80 6 10 8 109 58 61 9 87 12 9 16 104 49 56 14 62 6 3 33 78 45 55 9 70 6 I Tributaries Cu Pb Zn Cd Fe Mn Mg 29 33 77 58 74 12 70 8 105 40 57 38 40 17 72 7 02 34 85 22 33 5 43 5 132 40 32 25 25 9 66 5 Units : % -334- Table 7.29 Proportions of Non-Residual Heavy Metals in River Ecclesbourne Sediments Site Cu Pb Zn Cd Fe Mn Mg 352 58 111 64 73 . 25 84 48 318 57 64 93 83 30 80 28 328 56 116 61 72 23 80 25 321 54 98 51 71 21 78 17 336 46 100 59 77 22 73 17 325 37 124 51 70 16 76 20 327 48 94 46 85 17 83 16 351 50 99 45 77 17 72 20 Tributaries Site Cu Pb Zn Cd Fe Mn Mg 322 41 88 44 75 17 72 23 331 29 89 34 63 17 67 10 Units i % -335- Table 7.29 Analyses of Heavy Minerals Separated from Minsterley Sediments Site Cu Pb Zn Cd Fe Mn 33 8760 > 40000 160000 1224 18000 600 31 10400 >40000 320000 28000 38800 2560 28 1000 >40000 260000 2088 88230 2941 10 4200 23800 80000 640 87000 1500 3 540 1150 9300 89 230000 1750 126 68 516 672 6 208000 1120 Units : ppm -336- highly contaminated sites 33 and 31 to the less contaminated site 134. The proportions found at site 134 approximate to those found at background tributary sites such as 132, 105, and 129. The ratios for Zn and Cd at background sites 132 and 02, however, are approximately half those found at site 134. In order to interpret these observations, the data for the heavy mineral analyses must be consi- dered. The results of these analyses for Cu, Pb, Zn, and Cd are characterised by the decrease in concentration away from the mine site. This ref- lects the decreasing proportion of primary sulphide grains in the sediments, an inference confirmed by microscopical observation of non-separated samples of the -190 - 120 Jim size fraction used in heavy mineral analysis. Therefore to account for the patterns in the non-residual data a process involving the decrease in sulphide mineral content of the sedi- ments associated with an increase in the proportion of metals adsorbed to oxide surfaces, clays etc. can be envisaged. The dispersion of the sulphide grains will be connected to the physical process of sediment transport during which abrasion and chemical dissolution will occur. Abrasion of the sulphide will lead to a decrease in grain size with associated increase in surface area and vulnerabi- lity to chemical attack. Given a sufficiently high -337- Eh, dissolution (oxidation) of sulphides will occur at the surface of the sediments at the pH values observed in the stream water^ Typically river water of pH 7 will have an Eh of 0.4 volts (Levinson 1974). This value would probably be great enough to ensure oxidation of the sulphides, although at higher pH regimes >7.5 - 8.0 the redox potentials of sulphides tend to become pH dependent as hydro- lysis will control the metal ion activities (Hansuld 1966). Below the sediment surface highly reducing conditions can prevail in the interstitial waters causing the precipitation of secondary metal sul- phides. Decomposing organic matter collecting in areas of still water can provide a source of sulphur for these reactions (Jackson 1978). At the same time other processes are occurring in the sediments. With increasing distance from the mine dump, the influence of the waste material as a source of sedi- ment to the river decreases. This is evidenced particularly by the decrease in the calcium (calcite) content of the sediments. Additionally there is an increase in the proportion of material of silt size and less (-61 jim, see Table 7.34). The proportion of organic matter can also be expected to increase downstream. These factors will combine to increase the capacity of the sediments to adsorb heavy metals. This process will be encouraged by the increase in the water pH which, particularly in clays, greatly -338- increases the adsorption capacity due to the red- + uced competition with H for adsorption sites. The pH increase will also favour precipitation of secondary minerals. The role of Fe and Mn in the sediment geo- chemistry of the heavy metals is not easily ass- essed. The proportion of non-residual Fe decreases from 19% at the upper sites to between 5 and 9% further downstream. The proportion of non-residual Mn remains fairly constant, around 70 - 90% at all sites with no consistent patterns of variation em- erging. The concentration of Fe in the heavy min- eral phases rises from 18,OOOppm to 208fOOOppm from sites 33 to 126. The concentration of Mn is very low at site 33 (600ppm), rises to 2941ppm at site 28, and then declines to 1120ppm at site 126. The occurrence of Mn in the heavy mineral phases appears to be related to coatings on mineral grains, rather than discrete Mn minerals. The dispersion of Fe in the sediments seems to be related to two processes occurring simultan- eously. Firstly sulphide minerals containing Fe are being physically dispersed in the sediments from the mine dump. Secondly, amorphous Fe oxide coatings are being formed on sediment grains along with amor- phous "iron oxide" particles (see Section 7.3.1). The increasing concentrations of Fe in the heavy mineral phase seems to be related to this rather -339- th an to the occurrence of primary iron containing heavy minerals such as ilmenite and garnet. Evi- dence from optical examination of the separated heavy minerals is cited here. Unfortunately, the non-residual Fe data is ambiguous in that the prim- ary sulphides such as chalcopyrite and pyrite will be at least partially dissolved by 0.5M HC1. This might explain the decrease in the proportion of non-residual Fe to a fairly constant level of c. 10% downstream from site 33. The process of Fe precipitation can be demonstrated from the chemical data available for sites 33 and 31. In water emer- ging from underground at Gravels, the pH (and Eh) rise as the water equilibrates with CO2 in the at- mosphere (site 33 mean pH = 7.3, site 31 mean pH = 7.5). The filtrable Fe concentration drops sharply, from a mean concentration of 210ppb to a concent- ration of 94ppb. This is coupled with an increase in non-filtrable Fe from 36% to 46%, and an increase in the mean sediment Fe concentration (HNO^ attack) from 8100ppm at site 33 to 19500ppm at site 31. These data suggest a transfer of Fe from the disso- lved to the particulate and sediment phases of the stream. It can be anticipated that the mode of occurrence of other heavy metals will be affected by the reactions affecting Fe due to processes of co-precipitation and adsorption onto freshly formed amorphous Fe oxides. It is difficult to fully account for the sedi- -340- ment geochemistry of Mn using the present data. As with Fe, reagents capable of exclusively sepa- rating Fe and Mn phases from the sediments were not employed in this study. It is not possible, there- fore, to relate directly the geochemistry of the other heavy metals to that of Fe and Mn. Some pebbles stained with Mn oxides were observed in stream beds. No encrustations were found, however. Several stained pebbles were crudely analysed by dissolving the coatings in 4M HC1 (Whitney 1975) , which dissolves both Fe and Mn oxide coatings. Attempts were made to obtain weight loss due to dissolution of the coatings and thus produce res- ults on a dry weight basis. This approach had to be abandoned, however, as it was impractical for the small weight losses encountered. Two pebbles were analysed from each of four sites; three anom- alous (31, 30 and 28), one background (129). The results are shown in Table 7.32 as mean Mn/metal and Fe/metal ratios for each pair of analyses. This ratio was employed in preference to metal/Fe used by Carpenter R.H. et al (197 5) as the trends are more easily appreciated. Whitney (1975) also used Mn/metal and Fe/metal ratios. Table 7.32 Ratios of Mn/metal and Fe/metal for oxide Coatings - Minsterley Brook Mn/Cu Fe/Cu Mn/Pb Fe/Pb Mn/Zn Fe/Zn Mn/Cd Fe/Cd 129 1074 811 162 124 23 17 1812 141 31 337 269 1.2 1.0 1.4 1.1 236 188 30 140 133 2.3 0.8 2.3 1.1 199 246 28 226 1.2 1.1 1.1 1.9 1.3 150 411 -341 - The first observation that can be made is that ratios for the contaminated sites are between 1 and 2 orders of magnitude greater than the background site, with the exception of Fe/Cd. These general findings were also reported by Whitney (1975) and j-or in Hu Carpenter et al >. It can be seen from this that the oxides of Fe and 'Mn are acting as effective scavengers for heavy metals in Minsterley Brook. The data also show for Cu, Pb, and Zn that these metals are fairly equally partitioned between the two oxide phases at all the sites. The part- itioning of Cd changes, however, from predominance in the Fe oxide phase at sites 129 and 31 to enrich- ment in the Mn phase at sites 30 and 28. The data are too few to draw any firm conclusions on detailed element partitioning between the phases. It can be surmised, though, that oxides of Fe and Mn do play a very important role in controlling the geochem- istry of the other trace metals studied in Minsterley Brook. The data for the River Ecclesbourne are less complete, as no heavy mineral analyses were under- taken. Several features of the data reflect the differences between the catchments, however. The proportions of non-residual Pb remain fairly constant in the stream for its entire length, at approximately 100% (Table 7.30). This clearly reflects the general absence of discrete Pb minerals such as occurred in -342- Minsterley Brook. Site 318 however, is interesting in that the proportion of non-residual Pb drops to 64%, Lead minerals (galena) and smelter slag de- rived from road foundations have been found in this sediment, as mentioned, and this would account for the lowering in the ratio of non-residual metals. Zn and Cd behave differently, with an increase in the proportion of non-residual metals at this site. It is thought that the input from the sewage eff- luent of organic matter, Zn and Cd influence these results. Levels of total Zn and Cd in the effluent are equivalent to those occurring in water at site 352, upstream. Particulate organic matter contained in the effluent which might settle out at times of low flow in the river would also act as an effici- ent sink for Zn and Cd. Thus it might be antici- pated that levels of non-residual Zn and Cd would be elevated at this site. Oliver (1973) found a similar elevation of "available metals" in sediments directly below a municipal sewage works outfall in the Ottawa River. Iron behaves similarly to Zn and Cd with the proportion of non-residual metal elevated at site 318. The ratio then decreases downstream, possibly due to an input of Fe rich stable heavy minerals from the sandstones and pebble beds around the perimeter of the catchment. Cu does not behave in the same manner as Zn, Cd and Fe at site 318. Over the "period of sampling there is an increase in the mean filtrable Cu concentration -343- of 125% and in the mean particulate Cu of 220% be- tween sites 352 and 318. Filtrable Zn shows a slight decrease ( - 1%) and Fe a 16% decrease in concentration. Mean particulate Zn increases by 14% whereas mean particulate Fe shows a 16% decrease in concentration. Mn concentrations decrease between the two sites and the mean Cd concentration shows little change. The input of Cu from the sewage works has a significant effect on the chemical com- position of the river water. There is, however, no response to the input in the non-residual sedi- ment phase implying that Cu may be maintained in the water column. This may be due to complexation of the dissolved Cu by soluble organic matter in the effluent. The difference in the proportions of non-residual Cu, Zn and Cd between the two catch- ments is a result of the input of these metals in discrete mineral form to the Minsterley sediments. Oxide coatings on pebbles were collected and analysed as before. The data are shown as the mean for pairs of samples in Table 7.33, though unfort- unately no samples were obtained from a background tributary site. The increase in metal/Mn and metal/Fe ratios away from contaminated sites is again apparent. Metals are enriched in the Mn phase for all the sites except 321, but the data are again insuf- ficient to allow fuller comment. It can be infer- red, though lack of data for a background site make -344- Table 7.33 Ratios of Mn/metal and Fe/metal for Oxide coatings - River Ecclesbourne Site Cu/Mn Cu/Fe Pb/Mn Pb/Fe Zn/Mn Zn/Fe 321 1132 638 17 8 10 5 336 713 1900 17 42 14 36 325 319 1500 136 1462 20 218 Site Cd/Mn Cd/Fe 321 785 429 336 930 2355 325 1893 2036 -345- this difficult, that Fe and Kn oxides play an im- portant role in controlling the dispersion of heavy metals in the Ecclesbourne catchment. 7.8 Distribution of Metals in Relation to Sediment Grains!ze The chemical data for different size fractions in the sediments (non-residual heavy metals) are plotted in Figures 7.23 and 7.24. This form of data presentation clearly demonstrates the trends present. The chemical data are listed in Appendix 5, and the weights of each sediment fraction in Table 7.34. The metal concentrations are plotted on a log^Q scale to accommodate the wide range of values. The grain sizes are plotted on a Si scale' where 0 = - log2 S and S = grain diameter in millimetres. The data are plotted at the midway point of each fraction. Several features can be seen from the plots. A) Minsterley Brook i) The distributions for Cu, Pb, Zn, Cd and Fe tend to be similar at each site with minimum concentrations in the coarse (lmm-2mm) fraction and maxima in the fine silt fractions. This pattern is similar to that noted by Oliver (1973). ii) Mn tends to be uniformly distributed through out the grainsizes. -346- Table 7.25 Weights of Sediment Size Fractions Minsterley Brook 10/78 -2000+1000 -1000+500 -500+250 -250+l-25j -125+61 -61 33 186 135 70 20.5 3.7 2.1 31 165 240 222 78 23.5 6.5 28 202 229 185 31.8 14.5 7.2 10 153 86 53 31.8 14.8 8.9 03 221 187 155 25.0 10.3 7.6 River Ecclesbourne 06/78 -2000+1000 -1000+500 -500+250 -250+125 -125+61 -61 352 127.6 95 46.7 19.5 10.3 5.7 328 145.3 146.6 79.9 25.0 8.9 5.1 336 89.9 116.4 104.6 44.2 11.1 3.4 325 82.3 76.7 50.2 9.9 3.5 2.2 321 40.6 47.1 80.0 48.5 20. 3 8.4 Units i Weights of each fraction : g Grain sizes t pm -347- Site 31 Site 10 Ca 5 Ca. .Pb log ppm Mg - 2 4 .Cd Cu Cu Cd Cu. -1 -1 1 2 ^(=-log2particle diameter) s* Figure 7.23 Non-residual Metal Content of Sediments as a Function of Particle Size - Sites 33 and 10, Minsterley Brook -348- Site 321 Site 336 log ppm -1 -1 1 2 0 (0 = -log2 particle diameter) Figure 7.24 Non-residual Metal Content of Sediments as a Function of Particle Size - Sites 321 and 336, River Ecclesbourne -349- iii) Ca in all but site 33, has a maximum concen- tration in the coarse fraction and falls to a minimum in the fine. B) River Ecclesbourne i) The patterns for Cu, Zn, Cd, Fe, and Mn show that there is a maximum concentration in the fine fraction (silt) and a minimum in the fine and medium sand fractions. A second maximum occurs in the coarse sand fraction. These distributions which contrast with the Minsterley data are very similar to those found by Whitney (1975). ii) Pb behaves rather differently from the other elements. Maximum concentrations occur in the fine and medium sand fractions with minima in the coarsest and finest fractions. iii) Ca and Mg follow the trends of the heavy metals other than Pb. The trends observed are difficult to account for. The heavy metals in the Minsterley sediments correspond to a principle of increasing concentra- tion with increased surface area as proposed by Oliver (1973). This principle was further investi- gated by plotting the results for a number of ana- lyses against surface area of the sediment size fractions. The surface area was calculated as the specific surface area per unit weight using the -350- following relationship J S = 6 (Milner 1962) v d P vs where S^ = specific surface area <*vs = mean diameter of spheres P = density of spheres The assumption that the grains are spherical is probably valid for the particle sizes analysed here. The value of P was taken as the density of quartz (2.66g/cm ). The specific surface areas calculated on this basis are given below. Size Fraction Mean Particle Specific surface (cm) Diameter (d, ) Area0(S ) / v VS Z / w (cm) cm /g 0.2 - 0.1 0.15 15.04 0.1 - 0.05 0.075 30.08 0.05 - 0.025 0.0375 60.15 0.025 - 0.0125 0.01875 120.30 0.0125 - 0.00625 0.009375 240.60 < 0.00625 0.003125 721.80 The size fractions are given in cm. units as this greatly simplifies the final result of the calculation of surface area. Plots of Cd concen- tration against specific surface area for samples 10/78/31 and 10/78/03 are shown in Figure 7.25. Similar plots for Cd, sample 10/78/33, and Cu, sample 10/78/28, are contained in Figure 7.26. By way of comparison, the concentration of Cd in samples 10/78/31 and 10/78/03 are plotted against particle size (in mm) in Figure 7.27. Oliver (1973) calcul- -351- Fiqure 7.25 Non-residual Cd (Site 33) and Cu (Site 28) Content of Sediments as a Function of Particle Surface Area (Minsterley Brook) o in IC o o O£ £p as a Function of Particle Surface Area - Sites 03 and 31 (Minsterley Brook) 353- Figure 7.27 Non-residual Cd Content of Sediments as a Function of Particle Diameter (Linear Scale Plot) - Sites 03 and 31 Minsterley Brook -354- ated the surface area of Ottawa and Rideau river sediments using gas adsorption data. His data rep- resent the surface area of the total unfractionated sediment sample and it was this value which was plot- ted against the "available" heavy metal concentration. Despite this, the plots obtained in this work are very similar to those of Oliver (1973). Thus it can be seen that for the Minsterley sediments the concentrations of heavy metals are dependent on particle surface areas. Clearly the finer grained sediments will act as more effective "sinks" for heavy metals in the water column, since the increa- sed surface area will make large numbers of adsor- ption sites available for heavy metals. The beha- viour of Mn and to a'lesser extent Fe contrasts with that of the other heavy metals. In the samples from Minsterley, other than 10/78/03, the Mn con- centration decreases with decreasing grain size or remains constant, as in the case of sample 10/78/33. In sample 10/78/03, Mn follows the pat- tern of the other heavy metals, suggesting that it is itself adsorbed onto the exchange sites of clays or organic material, or that it coats the sediment particles at this site. At the other sites the distribution of Mn may be related to discrete min- eral phase such as nodules of Mn oxide derived from the bank soils. Further work is required to confirm these propositions. The element distributions in the Ecclesbourne -355- sediments are very similar to those reported by Whitney (1975). He related the patterns to the deposition of Mn oxide, suggesting that the heaviest deposition of the oxides occurred in fast moving, shallow, well oxygenated streams primarily on the surfaces of coarse particles. Subsequent transport and abrasion of the coarse material then leads to secondary concentration of oxides in the fine sed- iments augmented by Mn deposition directly onto clay and silt particles. This explanation gener- ally accords with the situation in the Ecclesbourne, which is a shallow fast stream at the sites sampled. Deposition of Mn oxide coatings on pebbles ( > 5mm diameter) was also noted at three of the sites (336, 325, and 321), and the significance of the coatings in controlling the heavy metal geochemistry in the stream has already been mentioned. In addition, the presence of organic matter in the fine fraction plus the effects of particle surface area noted with Minsterley sediments will tend to increase the con- centration of metals in the fine fraction. 7.9 Relationships between Metal Concentrations and River Flow Several relationships have been derived to ex- press the variation of solute concentration with discharge (e.g. Hall (1970) Johnson et al (1969)). The simplest model for a solute in a given stretch of river is one which assumes that a constant total -356- load of solute is entering upstream and that the observed concentration of that solute at the samp- ling point varies according to dilution by run-off. The simple equation C1Q1 + °2Q2 = + C3 ^ can be constructed where Q^ = volume of flow before dilution C^ = concentration of solute before dilution ~ volume of dilution water C2 = concentration of solute in diluting water C^ = final concentration observed The three terms in the equation represent loads of solute, and a balance of inflow with outflow is assumed (Hem 1970). If C-jQ^ is assumed constant (b) and C2 = 0, then b/ (Q + Q2) = C3, lo (Q + Q (2) i.e. log10C3 = log10*> - 9i0 l 2^ This equation is a straight line of slope -1. It is improbable, however, that or that will be constant; C2 may equal zero for the case of a specific pollutant entering a river e.g. from an out- fall, which is absent upstream of that source. If (Qj + C^) = Q 9 the river discharge and where C2>0 then log10Cij = a log10Qj + log10b (3) C^ is the concentration of constituent i of a sample j, and Q j is the discharge at the time of collecting j. (Edwards 1973b) The relationship may also be expressed as« C. . = fcQ^ where a = constant (4) 11 -357- The load (L. .) of a solute of concentration C. . is 1 j i j equal to C. . x Q thus L = bQ® x Q . = fcQ?+1 ij J J J J L or log10 ij = log1Qb + (a+1) log1()Q . (5) i.e. log1QL = mlog^gQ + log1Qb (6), where m = (a+l). Equations (3) and (6) have been evaluated for data from Minsterley Brook and the River Ecclesbourne. Sites 134 and 327 coincided with permanent flow measur- ing equipment of the Severn Trent Water Authority who have provided the relevant flow data (Table 7.35). VcuY H^V R\iv* a.*-*. The|relatively few chemical data must be considered when evaluating the results of the calcu- lations for the two rivers. These results are given in Tables 7.36 and 7.37. The regression lines for the elements Cu and Mg for the River Ecclesbourne are plotted as examples to illustrate the results in Figure 7.28. Estimates of losses of "dissolved" metals from each catchment were also made. This was done by eval- uating the load regression equations for each mean daily discharge value and summing over the yearly period covered by the chemical data. That is, November 1977 to October 1978 for Minsterley Brook and October 1977 to September 1978 for the River Ecclesbourne. The estimates are given in Tables 7.38 and 7.39. These estimates were checked by a simple calculation of the sum of the metal load for each two month period as followss -358- Table 7.25 Values of River Discharge for Rea Brook (Site 134) and the River Ecclesbourne (Site 327) 1) Rea Brook Date Flow (Kl/day) 20.12.77 186.4 23.02.78 269.0 26.04.78 159.9 5.06.78 55.4 24.08.78 34.3 18.10.78 22.9 2) River Ecclesbourne Date Flow (Ml/day) 20.10.77 14.3 9.12.77 159.0 9.02.78 87.8 12.04.78 38.3 12.06.78 13.6 9.08.78 41.1 -359- Table 7.39A Coefficients for Load and Concentration Regression Eguations for Minsterley Brook . log1QL = m log10Q + log b (1) log10C = 3 logm10Q ' + lo9 b Load equations (1) m log10b Cu 1.0282 0.3347 0.9726 Pb 1.1011 0.5789 0.8878 Zn 1.0941 1.7130 0.9800 Cd 0.8230 0.2822 0.8147 Fe 1.7332 0.4082 0.9805 Mn 1.8517 -0.2220 0.9722 Ca 0.9605 2.0077 0.9934 Mg 1.1038 0.9517 0.9701 Concentration equation (2) a log1Qb Cu 0.0282 0.3347 0.1141 Pb 0.1011 0.5789 0.1745 Zn 0.0941 1.7130 0.3902 Cd 0.1770 0.2822 0.2893 Fe 0.7332 0.4082 0.90361 Mn 0.8518 -0.2222 0.8858' Ca -0.0395 2.0077 0.3348 Mg 0.1038 0.9517 0.3517 * denotes values of r significant at p = 0.05 -360- Table 7.39A Coefficients for Load and Concentration Regression Eguations for the River Ecclesbourne log L = m log1QQ + log1Qb (1) log C = a log1QQ + log1Qb (2) Load eguations (1) m log^gb r Cu 0.9755 0.4538 0.9679 Pb 1.0447 0.6932 0.9347 Zn 1.4633 1.5016 0.9175 Cd 1.1585 -0.1510 0.9457 Fe 1.0178 2.0198 0.8250 Mn 1.2393 1.6899 0.9525 Ca 0.9710 1.7511 0.9981 Mg 0.7978 1.0286 0.9993 Concentration equations (2) lo b r a 910 Cu -0.0243 0.4538 0.0957 Pb 0.0447 0.6932 0.1117 Zn 0.4630 1.5016 0.5894 Cd 0.1573 -0.1510 0.3702 Fe 0.0179 2.0199 0.0257 Mn 0.2391 1.6899 0.5165 Ca -0.0276 1.7511 0.4166 Mg -0.2022 1.0286 0.98971 * denotes values of r significant at p = 0.05 -361- Load log1QL = log1QQ = l>og^Q Discharge Figure 7.28 Regression Plots of Log^Discharqe with Log n Load for Mq and Cu - River Ecclesbourne -362- T = H (C.Q.n.) where C.i = metal concentration ) • • )for the 11th sampling )occasion (i = 1-6) and Q^ = mean daily flow ) and n. = the number of days within the two month period covered by the sample i. T = total weight of dissolved metal lost from the catchment for the year. These estimates are also given in Tables 7.38 and 7.39. The estimated losses calculated in this manner must be treated extremely caoViousl^ Although high correlation coefficients were obtained when cal- culating the load/discharge regressions, it should be noted that the discharge term appears on both sides of the equation. For Minsterley Brook the loss estimates from the simplified calculations agree well with those obtained using the regression equations for Cu, Pb, Cd and Ca (3-11% difference). There is poor agree- ment for Zn, Fe, Mn and Mg which differ by 30 - 70%. This feature reflects the greater dependence of con- centration on river flow for the latter elements. Iron and Mn concentrations especially are correlated highly with flow (r=0.9036 and r=0.8858 respectively). The good agreement between the two methods of calcul- ation for Cu, Pb, Cd and Ca does to some extent help to validate the estimates. The metal loss estimates -363- Table 7.38 Estimated Losses of Dissolved Metals from the Rea Brook Catchmentj Nov. 1977 - Oct. 1978 1. Calculation from Regression Equations Cu Pb Zn Cd Fe Mn Ca Mg 115 298 3906 35 6645 3075 3800 713 2. Simplified Calculation Cu Pb Zn Cd Fe Mn Ca Mg 112 316 2153 40 1972 1170 3621 506 Units : Heavy metals, Kg Ca and Mg, Tonnes -364- Table 7.38A Estimated Losses of Metals Associated with Suspended Solids from Rea Brook Concentrations of Metals in Suspended_Solids (Dry Weight) Occasion Cu Pb Zn Cd Fe Mn 04/78 45 693 3465 139 19307 3465 06/78 47 1206 1934 47 151000 4953 08/78 52 909 1948 26 17532 4675 10/78 63 625 1141 31 14844 4453 Units : ppm dry weight Concentration Weight of Flow of (ppm) Suspended Solids (Ml/day) Suspended Solids (kg) 10.1 76.4 771.64 10.6 55.4 587.24 7.7 34.3 264.11 6.4 22.5 144.00 Metal losses (kq) Occasion Cu Pb Zn Cd Fe Mn 04/78 34.7 534 .8 2673.7 107 .3 14898.1 2673.7 06/78 27.6 708 .2 1135.7 27 .6 88673.2 2908.6 08/78 13.7 240 .1 514.5 6 .9 4630.4 1234.7 10/78 9.1 90 .0 164.3 4 .5 2137,5 641.2 -365- for the Ecclesbourne show good agreement between the two methods of calculation. The values obtained for Cu, Pb, Cd, Mn, Ca and Mg agree within 2-12%, despite the dependence of the concentration of Mn, Ca and Mg on river flow. The two values for Fe differ by 27% and yet this element has a very low correlation between metal concentration and river flow. The actual amounts of metal lost from each catchment show clearly that even when low concen- trations of metals are present in solution (tens of ppb), significant quantities of metal are tran- sported simply because large volumes of water are involved. An estimate of the particulate load has been made for the occasions on which the concen- tration of particulate material in the water sample was obtained. The product of this and the mean flow for the day of sampling then gives a value for the amount of material lost. The quantity of metal lost can then be estimated as the product of the amount of particulate material lost and the dry weight concentration of the heavy metal. Tables 7.38A and 7.39A give the results of these calcul- ations. The values obtained apply only to the day of sampling. Calculations based on load/discharge regressions were not attempted as there were only four data points, and hence the data cannot be extrapolated to cover a year. However, the esti- mates give an indication of the quantities of metal -366- Table 7.25 Estimated iLosse ——s of Dissolved Metals from —-—————the Rive—r Ecclesbourne Catchment, Oct. 1977 - Sept. 1978 1. Calculation from Regression Equations Cu Pb Zn Cd Fe Mn Ca Mg 60 105 786 16 2214 1087 1189 227 2. Simplified Calculations Cu Pb Zn Cd Fe Mn Ca Mg 65 119 1078 15 2994 1216 1215 235 Units : Heavy metals, Kg Ca and Mg, Tonnes -367- Table 7.39A Estimated Losses of Metals Associated with Suspended Solids from the River Ecclesbourne Concentrations of Metals in Suspended Solids Occasion Cu Pb Zn Cd . Fe Mn 02/7 8 88 1284 1189 34 29054 2297 04/78 194 1111 2583 194 59722 15278 06/78 786 10000 8000 429 428571 45000 08/78 86 1379 724 - 47414 3621 Units t ppm dry weight Concentration Flow Weight of of (ppm) (Ml/day) Suspended Solids Suspended Solids (kg) 8.2 87.8 720.0 49.4 38.3 1892.0 4.7 13.6 63.9 5.8 41.1 238.4 Metal losses (kg) Occasion Cu Pb Zn Cd Fe Mn 02/78 63.4 924.5 856.1 24.5 20918.9 1653.8 04/78 367.0 2102.0 4887.0 367.0 113* 28906.0 06/78 50.2 639.0 511.2 27.4 27385.7 2875.5 08/78 20.5 328.8 172.6 11303.5 863. 2 * Metric tonnes -368- lost from contaminated catchments in the partic- ulate phase. The high concentration of suspended solids in the Ecclesbourne on occasion 04/78 was caused by excavation works on the river "banks about lkm upstream of the sample site. The work had the effect'of disturbing large quantities of bed sedi- ment and bank soil, giving the water an opaque brown appearance. River flow was measured at between 6 and 7 sites on Minsterley Brook using a hand held current meter on three sampling occasions, the data for which are given in Table 7.40. Table 7.40 River Flow at Sample Sites on Minsterley Brook Occasion Site 06/78 08/78 10/78 30 32.3 15.2 13.3 28 49.1 28.4 19.9 107 133. 2 75.9 59.6 10 136.4 - - 3 406.0 241.4 183.3 126 509.8 299.7 208.4 134 641.2 397.0 269.7 The flow at site 10 was not measured on 08/78 and 10/78 owing to the poor defination of the stream channel at this point during low flow conditions. The values for 134 are those taken from the Severn Trent Water Authority permanent installation. Flow was also measured at site 33. However it was moving through thick gravel, deposits at this point -369- making the validity of even crude estimates rather doubtful. In order to relate the values of flow to metal concentration the equation log C = log b - a log Q (equation 5 above) was evaluated using the obser- ved filtrable metal concentrations and the measured values of flow for each site. The regression co- efficients and r values are given in Table 7.41, and plots for Pb, Zn, Cd and Ca for 06/78 to illus- trate the relationships are given in figure 7.29. The regression equation fits the majority of the data very well, often with highly significant values of r (e.g. 06/78 Pb, r=0.9742, 08/78 Cd, r=0.9820, 08/78 Pb, r=0.9888). The coefficient 'a' for the heavy metals is always negative, signify- ing that dilution is occurring with increased flow. The value of 'a' for Zn and Cd approaches very closely to -1 (e.g. 06.78 Zn, a= -0.9224, 08/78 Cd, a= -0.9974) which means that the theoretical condi- tions for the simple dilution model are virtually satisfied. In reality this probably indicates that the concentrations of these elements in di- luting waters are very low compared with levels in the mainstream. The assumption that (e<3ua~ tion 5) is constant is probably valid for the time period required to make the flow measurements. Chemical data for tributaries entering Minsterley Brook and Rea Brook confirm the presence of low -370- Table 7.39A Regression Coefficients for Concentration - Flow Equations for Minsterley Brook 06/78 a log b r Cu -0.1312 0.7191 0.8212 Pb -0.6762 2.5411 0.9742 Zn -0.9224 4.5187 0.9445 Cd -1.1920 2.9898 0.9740 Fe - .2838 2.3564 0.6091 Mn -0.2668 2.0599 0.5142 Ca 0.2045 1.3117 0.8992 Mg 0.1870 0.5147 0.8513 08/78 a log b r Cu -0.0486 0.5253 0.4999 Pb -0.3861 1.8211 0.9888 Zn -0.8605 4.2861 0.9695' Cd -0.9974 2.4382 0.9820' Fe -0.2256 2.2965 0. 9388' Mn -0.0977 1.6420 0.3575 Ca 0.1547 1.5046 0.8612' Mg 0.2071 0.5603 0.8168' 10/78 a log b r Cu -0.0399 0.4665 0.2826 Pb -0.2461 1.5064 0.88011 Zn -0.9751 4.4296 0.92961 Cd -0.8371 2.1656 0.9360" Fe -0.3985 2.3398 0.91441 Mn -0.5942 2.4318 0.7955' Ca 0.1913 1.4777 0.9511' Mg 0.2119 0.6101 0.89851 ^denotes values of r significant at P = 0.05 -371- [Pkl Log^C = Log^Q Metal Concentration Log^^Q = Log^Q Discharge Figure 7.29 Regression Plots of Log^Q Concentration with Log^ Discharge for Pbt Zn, Cd and Ca - Minsterley Brook -372- IGVGIS of Zn and Cd in at least some of tho dilu- ting vaters. The other heavy metals all have values of 'a' which are considerably less than -1. Where significant regressions exist, these indicate that chemical processes as well as dilution are control- ling the element concentration in the water. That is, the concentration of a particular metal in the water at each site is less than that predicted on the bases of a simple dilution model. The positive values of 'a' for Ca and Mg reflect the increase in concentration of these components with increas- ing discharge. Important sources of Ca and Mg to the system are tributary drainage (see Ca and Mg d?ta for sites 105 and 132, Table A4.9) and run- off from cultivated agricultural land. These are probably more significant than the dissolution of Ca and Mg minerals in the stream sediments, espe- cially in view of the high pH of the river water. 7.10 Analytical Control Data Adequate "quality control" data for the water analyses were difficult to obtain in quantity owing to the lengthy nature of the sample preparation. Several replicate analyses for filtrable metal and total exchangeable metal concentrations were performed on samples collected from sites 031 and 02 (Minsterley Brook) and sites 318 and 331 (River Ecclesbourne). The sites were chosen to represent -373- anomalous and background levels of metals found in the rivers. Summarised results are given in Tables 7.12 and 7.13. In addition 6 bulk water samples were taken from the Ecclesbourne, split into 25 replicates of 1 litre each (i.e. 5 from each bulk sample) and each replicate analysed. The summarised results for this study are given in Table 7.42. The results of the analyses of "spiked" samples (15) of Deionised Water (DIW) and control samples (20) of DIW are given in Table 7.43. The results for the former are expressed in terms of the percentage recoveries from the samples. Table 7.44 contains summarised data for samples M203 and D319 which were analysed repeatedly fol- lowing nitric acid attack, 0.5M HC1 leach and HNO^ - HCIO^ attack. Summarised results are given in Tables 7.8 and A4.18 for the analyses of the sed- iment samples collected from each of the following sites: 08/78/31 and 08/78/03 on Hinsterley Brook and 08/78/328 and 08/78/351 on the River Ecclesbourne. Six samples were collected at each site and five replicates were analysed from each sample using a nitric acid attack. A 1-Way ANOVA was per- formed on the results to compare the variation bet- ween samples at a given site with the between replicate -374- Table 7.42 Results of Analyses of Replicate Bulk Water Samples Replicate Means for Each Subsample (Filtrabl e Metals) Subsamplp Cu Pb Zn Cd Fe Mn 1 1.1 4.9 22.3 0.33 30.0 3.1 2 1.5 6.3 38.9 . 0.50 30.2 3.4 3 0.9 4.7 18.1 0.66 28.9 3.2 4 1.1 4.9 19.2 0.42 30.2 2.9 5 1.0 4.9 17.3 0.32 29.6 3.2 6 0.8 5.1 20.3 0.30 28.8 3.3 Units : ppb N = 5 replicates Statistics for Combined Subsamples Cu Pb Zn Cd Fe Mn Mean 1.1 5.2 22.7 0.43 29.6 3.2 S.D. 0.32 0.63 7.50 0.18 0.97 0.30 C.V.% 29 12 33 42 3 9 Max. 2.2 7.0 40.0 0.3 33.0 3.5 Min. 0.7 4.0 16.0 1.0 28.0 2.5 N = 30 Results for 1-Way ANOVA Element F ratio Cu 5.60 Pb 11.76 Zn 239.94 Cd 4.48 Fe 2.63* Mn 1.78** * significant at p 0.01 ** significant at p 0.05 -375- Table 7.25 Recoveries from "Spiked" and Control Samples of DIW "Spiked " samples, N == 15 Cu Pb Zn Cd Fe Mn Mean 100.67 96.5 109.0 99.1 125.4 97.6 S.D. 4.53 6.24 5.67 3.37 8.24 4.91 C.V. 4.5% 6.5% 5. 2% 3.4% 6.6% 5.0% Max. 106.5 110 122.5 105 137.5 105 Min. 88 90 100 90 105 90 Control Samples , N = 17 Cu Pb Zn Cd Fe Mn Mean 0.29 N.D. 1.72 0.15 3.61 N.D. S.D. 0.15 - 1.23 0.01 2.75 - C.V. 52% - 7 2% 6.7% 76% - Max. 0.60 - 5.55 0.4 9.5 - Min. N.D. _ 0.5 N.D. N.D. — Units : ppb N.D. s none detected -376- Table 7.44 Analyses of Standardised Sediment Samples Sample M203 (Nitric Attack) Cu Pb Zn Cd Fe% Mn Ca/b Mg Mean 7-9 269 658 4.72 1.92 322 3,38 5969 S.D. 0.56 19. 5 70? 3 0.51 0.13 19.4 0.10 173.4 C.V.% 7.11 7. 25 10.68 10.80 6.69 6.0 3.0 2.9 N = 15, Units : ppm Sample D319 (Nitric Attack) Cu Pb Zn Cd Fe% Mn Mean 6.0 773 159 1.5 1.14 303 S.D. 0.44 42.3 13.1 0.48 0.034 11.8 C.V.% 7.4 5.5 8.2 32 3 3.9 N = 8, Units x ppm Sample M203, 0.5M Hcl leach Cu Pb Zn Cd Fe Mn Ca Mg Mean 2.67 173.5 231 3.3 913 222 3.25 4567 S.D. 0.3 10.1 18.9 0.13 86.2 15.9 0.31 299 C.V.% 11.8 5.8 8.2 3.9 9.5 7.2 9.51 6.55 N = 11, Units i ppm Sample M203, HNO., - HC10 wt -4 Cu Zn Fe% Mn Ca% Mg Pb Cd Mean 9.1 626 2.62 331 3.09 6889 292 4.9 S.D. 0.89 45.1 0.12 15.2 0.05 215 22.9 0.25 C.V.% 10.0 7.0 4.6 5.0 2.0 3.0 8.0 5.0 N = 9, Units * ppm -377- variations. Results for this are given in Table 7.9 (see also Sections 7.3.3 and 7.3.4). The cal- culations were performed using the GENSTAT package. The bulk of the results presented here are commented on in Sections 7.3.3, 7.3.4 and 7.3.7. The element recovery data for the solvent extrac- tion shows that the method works well, at least for simple deionised water - metal systems. Un- fortunately no data were obtained for spiked samples of river water. The high mean recoveries for Zn and Fe represent contamination by these elements, also detected in the control DIW samples. Iron contam- ination is extremely difficult to avoid. In a laboratory where acid vapours are present, any un- painted metal surface soon becomes coated with "rust". Dust from this source can easily be tran- sferred to samples at any stage of the processing and analysis. Additionally, the location of the laboratory in central London means that the air generally contains a high particulate loading rich in heavy metals. Zinc, the other major contaminant in the analyses, occurs in most of the reagents used in the analysis of samples and cleaning of glassware. Often zinc occurs in these reagents at greater concentrations than Fe, for example, hydrochloric acid 22ppb Zn, approx 2ppb Fe (Robert- son 1968a). A major potential source of zinc con- tamination is "Kimwipe" laboratory tissue which -378- has been found to contain 48ppm Zn and lppm Fe (Robertson 1968a). This material was used exten- sively in the laboratory for tasks such as wiping glassware and clearing spillages until the potential contamination problem was realised, from which time its use was restricted. Lead recoveries were generally the lowest for the elements determined during this study. This was also reported by Watling (1974), who was in part responsible for the development of the method. The poor recovery is probably due to the extraction pH (4.6 - 5.2) used in this method being slightly higher than that which is optimal for Pb (3.6) (Olsen and Sommerfield (1973)). However, as several elements were to be extracted at once, this compromise in the extraction pH was adopted. In addition the sensitivity of flame AAS analysis for Pb is poor, making precise determinations at low concentrations difficult. The analytical precision for the replicated water analyses (Table 7.42) as expressed by the C.V. values for each replicate are generally poorer than for spiked samples of DIW as would be expected. The variation in the Cu and Cd data is particularly large, reflecting a fall off in precision as the concentrations approach the detection limit of the method (0.5 ppb for Cu and 0.2 ppb for Cd) . The results for the nested 1-Way ANOVA indicate -379- however, that the between replicate variation is not statistically significant, with the exception of Zn. However, the between sample variation is significant except for Fe and Mn. Thus, apart from these two elements, sampling error constitutes a more significant source of data variability than analytical error, even for elements occurring at low concentrations. The replicate sediment data for samples D319 and M203 give a measure of the analytical precis- ion between batches of samples. All three methods of sample attack have good precision, with CV's in the range of 3-11%. These values agree well with those obtained from the replicate analyses of sed- iments already reported for the four sitesi 351, 328, 031, 03. These precisions are certainly ad- equate for the work in this project. The coeffi- cient of variation for Cd for sample D319, is very high (32%). This is probably because the low Cd concentrations in the sample solutions are very close to the detection limit for the method. -380- CHAPTER 8 CONCLUSIONS AND RECOMMENDATIONS FOR FURTHER RESEARCH 1. Gravels mine dump in the headwaters of Mins- terley Brook provides a unique point source of heavy metals to the sediments and water of the river system. This occurs both by physical col- lapse and degradation of the waste material and by the input of metal laden drainage water leach- ing through the dump. Mine drainage adits located at Gravels, its immediate vicinity, and elsewhere in the catchment constitute secondary sources of soluble and particulate heavy metals. These adits can be very important locally as the WHO * s Highest Desirable Limits (HDL) for drinking water are ex- ceeded for Cd in most cases by the adit effluents. The adits also provide a fairly consistent water supply during periods of drought. This permits them to exert a much increased and important inf- luence on the heavy metal chemistry of the stream. Although draining a sulphide mineralised area, drainage and stream waters in Minsterley Brook have a high pH (6.0 - 8.5) reflecting the buffer- ing capacity of the abundant calcite mineralisation. The historic influence of the mineralisation and mining on the catchment can be seen from the con- tamination of river banks-and soils within the river valley. Soil contamination is generally -381- restricted to the immediate vicinity of the brook and to mined areas and associated features such as disused mineral railway lines and mineral processing plants. Contaminated river bank material can form a source of heavy metals to the system through collapse and leaching. 2. The major source of metals to the Ecclesbourne is thought to be the mineralisation at the head of the catchment. Two other secondary sources of contamination were identified in the head waters of the river. These were* i) Mine waste material utilised in a road and a railway embankment adjacent to the river at sites 318 and 352. These provided a source of galena to the river sediments. ii) A water reclamation works discharging effluent into the Ecclesbourne upstream from site 318. A number of heavy metals are carried | into the river of which Cu appears to have fche most significant effect on the chemical composition of the stream water. Bank alluvial soils in the catchment reflect the historic accumulation of heavy metals in the river sediments. -382- Dispersion of Cu, Pb, Zn and Cd in the sedi- ments of Minsterley Brook and the River Ecclesbourne follows consistent well defined patterns with dis- tance over the six sampling occasions. Ca and Mn in sediments in Minsterley Brook also conform to similar patterns. Between occasion variation occurs in the stream sediment data, but this is usually statistically insignificant compared with between site variation and does not often influence the data sufficiently to mask dispersion trends. For Fe and Mn in both catchments the variation between occasions at each site is statistically significant compared with the between site variation, and apart from Mn in Minsterley Brook, these elements do*^not exhibit well defined dispersion curves. A high degree of variation in the sediment data occurs at highly anomalous sites, and seems to be related to problems of representative sam- pling in addition to any seasonal effects. Con- siderable sampling variation can occur on a very localised scale (within 100m) and this can cons- titute a very major source of error in seasonal stream sediment geochemical data. In addition, a high degree of analytical variation can also be expected at sites where the element occurs at concentrations close to the detection limit. In general, the methods of analysis used in this work for stream sediment analyses provide data with -383- adequate accuracy and precision for seasonal studies. The downstream dispersion patterns of heavy metals in water are not always so clearly defined as in the sediments, with the exception of filtra- ble Zn, Pb and Cd in Minsterley Brook. This prob- ably relates to the poorer contrast between control and anomalous sites in water compared with sediment data. Between occasion variations occur in the data for both filtrable and total exchangeable heavy met- als. These variations, for each river, are stat- istically significant compared with the between site variation, with few exceptions. Clearly, seasonal fluctuations in metal concentration in waters must be considered in any examination of trace heavy metals in river systems. Sampling and analytical variations in the data are generally insignificant in relation to the between occasion variations. The variation occurring in the total exchan- geable metal data for waters at individual sites is particularly large. Two variables are intro- duced with this measurement; the concentration of metal associated with the suspended particulate material and the quantity of particulate matter actually present in the water at the time of samp- ling. This latter factor" is highly dependent on flow rates. Consequently, dispersion patterns for -384- total exchangeable heavy metals tend to vary appre- ciably between sampling occasions. For these reasons it is considered that "total metal" determinations are unsuitable for monitoring heavy metals in stream water. More consistent and useful information can be obtained from the analysis of filtrable metals. Work reported by Thorne (1980,'pers. comm.) suggests that filtration on site followed by acidification is preferable for filtrable metal analyses in order to prevent changes in metal speciation and the exchange of metals between "dissolved" and partic- ulate phases. 7. Seasonal variations occur in the stream sedi- ment data, though the trends differ between the river systems and between sites within each system. Important mechanisms thought to be in part respon- sible for the variations include* i) The introduction of fresh material to the river during periods of high river flow by erosion of mine waste and contaminated river bank material. This is thought to be parti- cularly relevant at the contaminated sites in the headwaters of Minsterley Brook. ii) The removal of fine grained metal rich sedi- ment during high river flow. Additionally the effects of river temperature -385- on biological activity, though unmeasured, are also thought to be significant controls on the variation in stream sediment data. Variations also occur seasonally in the fil- trable -water data, though again trends differ between the rivers and between sites within the rivers. In the Ecclesbourne, concentrations of heavy metals, with the exception of Cu, tend to decrease in the summer months from high levels in autumn and winter. However, detailed variations from this trend do occur. It is thought that the general pattern may reflect a seasonal cycle of biological activ- ity. For Minsterley Brook, trends are not easily recognised although the major cations tend to in- crease in concentration through the year from December. 8. The two month sampling period for stream waters is probably too long. It is thought that short term variations in stream water chemistry in response to climatic/biological processes may mask seasonal trends measured on a relatively coarse time interval. For the pollutant elements, the stream sedi- ment data generally provide a more seasonally stable assessment of the metal status of the river system than the filtrable water data. Thus -386- stream sediment data can be used to predict stream water quality in the rivers examined in the study. Two criteria have to be satisfied for this appli- cation to be successful: i) the pollutant must enter the system from a point source ii) the concentration decay curve with distance for the element must be well defined and similar in both the dissolved water and stream sediment phases. Consistently high correlations between filtrable metal levels and the concentrations of metals in sediments can therefore be expected. It is then possi- ble, given suitable sediment threshold values related to water quality limits, to predict from the sediment data likely points in a river where these limits might be exceeded. However, the correlations are of restricted value unless an acceptable threshold value for the sediments can be established. Aston and Thornton (1977) have suggested tentative sediment threshold values for water quality assessment applicable to soft water areas. These are shown belowt -387- Element WHO Highest Desirable Tentative Sediment Limit (ppb) Threshold Value (ppm) Fe 100 6% w/w Mil 500 1000 Cu 50 1000 Pb 50 500 Zn 5000 2000 Cd 10 10 (after Aston and Thornton 1977) The WHO HDL's are only exceeded for Pb, Cd and Fe in Minsterley Brook and Fe in the River Ecclesbourne. The sites at which the recorded maximum filtrable metal concentration exceeds the HDL are given below, along with the respective mean sediment values. Minsterley Brook Element Site Sediment Concentration (ppm) Pb 10 3407 Cd 28 , 75 * (10) (35.4) Fe 351 2.21% w/w River Ecclesbourne Fe 351 2.70% w/w At the site marked *, the EEC recommended limit for Cd in drinking water (5 ppb) is exceeded by the maximum recorded filtrable metal concentration. It is clear from these data, that for Pb and Cd the values suggested -388- by Aston and Thornton (1977) are far exceeded in the sediments, whereas for Fe the recommended thres- hold value is too conservative. The recommended value for Zn is exceeded at site 9 (2440 ppm) in Minsterley, yet the maximum recorded Zn concen- tration is only 400 ppb. Even at highly contam- inated sites, where mean sediment Zn concentrations exceed 34000 ppm, the highest recorded filtrable Zn concentration (2069 ppb) is less than half the WHO HDL. The available data are too few to suggest sediment threshold values for hard water rivers. The extent of the problem has been highlighted, however. 9. In Minsterley Brook, the sediment geochemistry of Cu, Pb, Zn and Cd is probably dominated by pro- cesses involving the decrease in the primary sul- phide mineral content of the sediments by abrasion and dissolution, coupled with an increasing capacity of the sediments to sorb trace elements. This in- creased capability for sorption can be related to an increase in the -61 jam material in the sediments. This is accompanied by the scavenging activity of hydrous oxides of Fe and Mn. The increase in -61 jam material occurs as the influence of the mine dump as a source of sediment to the river decreases. This can be conveniently indexed by the decreasing Ca concentration in the sediments. The increasing pH of the river water will tend to promote sorption -389- reactions and will also favour the precipitation of secondary mineral species, such as carbonates and hydroxides. It is important not to underest- imate the significance of this latter process in Minsterley Brook. A process that also affects the levels of dissolved constituents in Minsterley stream water is that of dilution. A simple dilution model has been used to account for the observed dispersion patterns of filtrable Zn and Cd on three separate occasions. It is not possible, however, to assess the significance of dilution relative to chemical processes in the geochemistry of heavy metals in Minsterley Brook as Zn and Cd will not act as chem- ically inert species. However, it appears that dilution is a major process accounting for the dispersion of these elements in the water of the Brook. The data for the River Ecclesbourne are less detailed, but the geochemistry of this river may still be compared with that of Minsterley Brook in several ways. The absence of a source of dis- crete sulphide minerals is reflected in the increa- sed proportions of non-residual metals in the sedi- ments. The small localised source at site 318 is however highlighted. Sulphide mineral degradation is not an important geochemical process in these -390- sediments. It is probable that the other geochemical processes controlling or influencing metal dispersion in the Ecclesbourne are similar to those in Minsterley Brook. Precipitation of Fe and Mn oxides are shown to influence the geochemistry of the trace metals, and the high pH regime and abundance of carbonate species may also promote precipitation of secondary mineral species. The input of effluent from the Water Reclamation Works modifies the trace element geochemistry of the river. The proportions of non-residual Zn, Cd and Fe in the sediments adja- cent to the outfall are higher than those at the site upstream of the works. There is also a sig- nificant input of Cu from the works, but this metal tends to remain in solution. The relationships between heavy metal concen- trations and sediment grain size exhibit a contrast between the two rivers. In Minsterley Brook, the finer grained material clearly acts as a more effec- tive sink for heavy metals than the coarser particles. The clearly defined relationship between element concentration and particle surface area confirms this. The distribution of heavy metals with re- spect to grain size is different for the River Ecclesbourne, and is probably related to the de- position of Mn oxides on coarse particles followed by reworking and concentration in the finer frac- tions. -391- The loss of trace metals from river systems is an important environmental consideration even when the metals are present in relatively low con- centrations (tens of ppb). Although not directly relevant to these systems, it is clear that even mildly polluted rivers can have a very significant impact on lakes and estuaries ("sink" areas for heavy metals). Recommendati ons The work reported in this thesis has inevit- ably suggested several areas for further research. In particular, a more detailed and specific exam- ination of the processes proposed as controls on the heavy metal geochemistry of Minsterley Brook is required. Avenues of approach would include I i) the speciation of dissolved heavy metals using electrochemical techniques ii) the speciation of heavy metals in sediments using selective chemical leaching and/or electron microprobe or SEM microanalysis of resin impregnated thin sections of sedi- ments . iii) an examination of the role played by organic material in sediments, suspended solids and in solution in controlling heavy metal geo- chemistry. -392- Similar studies should be conducted to examine in detail the effects of sewage effluent on trace metal speciation in the River Ecclesbourne. The methods of analysis used in this work generally provided data of suitable accuracy and precision for the research programme conducted. It is desirable, however, to develop a rapid routine method for the analysis of trace metals in water which does not require a preconcentration technique. Modern AAS equipment utilising flameless atomisation or inductively coupled plasma source emission spec- troscopy could provide this. The latter instrument also offers the advantage of multi-element analyses from single samples. Any new method of analysis should be accompanied by the revised sampling methods suggested by Thorne (1980, pers. comm.) and mentioned in chapter 7. The relationship between trace metal concen- trations and river discharge remains an area where much work is required, covering items such as de- tailed variation during storm events as well as longer term relationships. This work could clearly be coupled with an examination of seasonal varia- tions (i.e. variations over yearly periods) using a monitoring programme extending over several (at least three) years. To investigate the mechanisms responsible for seasonal variations in metal con- centrations in sediments and water a measurement -393- of the impact of the biological activity in a stream upon trace metal behaviour is required. Thus a detailed seasonal study would also need to examine topics such as the uptake and release of metals by organisms during growth, death and decay and the variations in biological activity which occur throughout the year. Suitable sediment threshold concentration values for water quality assessment are still required. A simple comparison between this work and that of Aston and Thornton (1977) highlights the extent of the problem. The examination of a large number of rivers encompassing a wide variety of geochemical environments is necessary before truly realistic values of widespread application can be determined. -394- BIBLIOGRAPHY -395- Abdullah, M.I. and Royle, L.G. (1972). 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(Ed) Advances in Chemistry Series, 147, 82-98. ACS, Washington. -423- APPENDIX 1 Methods of Chemical Analysis -42 4- Nitric Acid Attack for Soils and Stream Sediments 1) Place 0.25g of dried sample (-200^im) into a clean dry 180 x 18mm rimlessJ^test tube. 2) Add 1ml of concentrated (16M) nitric acid and leach for 1 hour at 105°C to 110°C. 3) Allow to cool, and dilute to 10ml by the addition of 9ml of DIW. 4) Mix the solutions thoroughly and allow to stand overnight before analysis by AAS. Notes i) Nitric acid must be of BDH AnalaR grade or equivalent. ii) Perform one control digestion for every 9 samples to check for reagent and glassware contamination. iii) The final volume of solution gives a dilution factor of x 40. Thus the concentration of metal in the original sample = the analytical result x 40ppm (pg/g). -425- Cold 0.5M Hydrochloric Acid Leach for Stream Sediments 1) Place lg of dried sediment (-200 ^im) into a clean dry screw-top hard polythene bottle, (150ml - capacity). 2) Add 20ml of 0.5M hydrochloric acid and shake for 4 hours on a reciprocal shaker. 3) Filter the solution through an acid washed Whatman No 40 filter paper (9cm diameter) into a clean dry test tube. 4) Cover tubes with clear polythene film until analysis by AAS. Notes i) It is important to ensure that the polythene bottles have water-tight lids. Cardboard inserts and rubber sealing rings should be removed from the lids to prevent contamination. Leaking bottles may be sealed, however, with white PTFE tape. ii) With highly calcareous samples, (>10% w/w CaCO^), the pH of the solution should be checked after 10-15 minutes. Further acid may be added in 5ml aliquots to restore the solution to pH <2. -426- iii) For the analysis of 8 elements 10-15ml of filtered solution is sufficient. iv) Perform a control determination for every 9 samples to check for reagent and glassware contamination. v) Acid should be of BDH AnalaH*grade or equivalent. -427- Nitric Acid - Perchloric Acid Attack on Stream Sediments 1) Place 0.25g of dried sample ti(-200 um) into a clean dry 180 x 18mm rimless test tube. 2) Add 4ml of concentrated nitric acid and 1ml of concentrated perchloric acid; 3) Heat at 140-160°C until about 1ml of the original solution remains. 4) Increase the heat to 180°C and fume down solutions to approaching dryness (pale yellow colour). Take care not to char the residue at this stage. 5) Allow to cool and leach residue at 55-60°C with 2ml of 6M hydrochloric acid for 20-30 minutes. 6) Add 8ml of DIW to give a final solution volume of 10ml. Notes i) All acids must be BDH AnalaR grade or equiv- alent. ii) The final volume of solution gives a dilution factor of x 40. Thus, the concentration in the original sample = the analytical result x 40 ppm, -428- Chelation-Solvent Extraction System for the Determination of Cd, Cut Fe, Mn, Pb and Zn in Natural Waters A. Extraction Procedure 1) Place 1000ml of sample into a 21 separating funnel and adjust the pH to approximately 7 by the addition of ammonia solution. 2) Add 20ml of SDDC/buffer solution and adjust the pH to 5.8-6.1 by the dropwise addition of either ammonia solution or 16M nitric acid. Shake for c. 10 seconds after each addition to ensure complete mixing. 3) Add 25ml of chloroform and shake for 5 minutes. 4) Allow phases to separate and run the chloroform layer into a 100ml Quickfit Erlenmeyer flask. 5) Add a further 25ml of chloroform to the separ- ating funnel and shake for 5 minutes. Add the separated phase to the initial extract. 6) Add 1ml of 16M nitric acid for every 25ml of chloroform extract and place the flask on a hot plate. 7) Gently evaporate the combined chloroform extracts to dryness, without boiling. t -429- 8) The residue in the flask should be a white colour. If darker than pale yellow, add a further 1ml of 16M nitric acid and evaporate to dryness. Repeat, if necessary, until all the organic matter has been destroyed and a pale yellow/white residue remains. 9) Take up the salt residue in exactly 5ml of 1M hydrochloric acid, stopper, and leave over- night to ensure complete dissolution. 10) Swirl the flask contents to ensure mixing and determine the metal concentrations by AAS. 11) Perform a control determination, repeating steps 1-10 on 1000ml of DIW. B. Preparation of the Sodium Diethyldithiocarbamate (SDDC) / Buffer Solution Add 250g of sodium acetate trihydrate to 500ml of DIW and mix to dissolve. Pour 6ml of glacial acetic acid into the solution and mix thoroughly. Add 50ml of SDDC to this buffer solution and mix thoroughly. Check the pH and adjust to 7.0-8.0 with ammonia solution. Hake up the SDDC/buffer solution to 1000ml with DIW and pour into a 21 separating funnel. If the buffer is correctly prepared, the pH at this stage should be 8-9. Extract any SDDC-metal complexes by successive -430- extractions with 25ml of chloroform, until consecutive extracts are colourless. Notes i) All* reagents must be of BDH AnalaR grade or equivalent. Fison's Distol grade chloroform was used. The ammonia solution is isothermally distilled 0.880 SG AR grade. That is, the ammonia gas is allowed to equilibrate, in a closed system at room temperature, between the original ammonia solution and a similar volume of DIW. ii) Cleanliness of apparatus and precautions against contamination at all stages are essential. Glass- ware should be soaked in 2% v/v DECON 90 solution followed by soaking in 10% v/v nitric acid and 4 rinses with DIW. Before beginning a series of extractions, the separating funnel should be cleaned by shaking with SDDC/buffer solution and rinsing with DIW 4 times. iii) A piston type "Oxford" pipette proved convenient for dispensing SDDC/buffer solution and hydro- chloric acid. iv) The pH values in Al, A2 and B are checked by removing a drop on a glass rod from the flask and using the appropriate narrow range test paper. -431- v) Where high trace element concentrations are evi- dent, i.e. an immediate deep colour or precip- itate is formed on the addition of the SDDC/ buffer solution, carry out a 30ml and then a 20ml chloroform extraction before continuing at A2. vi) The SDDC/buffer solution is unstable under acid conditions and rapidly decomposes. The pH of the solution on standing for a short while after preparation should be approximately 9. At this pH, the SDDC solution has been shown to be stable for at least one month, (AGRG 1975). -432- APPENDIX 2 Sample Sites and Grid References -433- Minsterley Brook Site Grid Reference Site Grid Reference No. No. 001 SJ 348023 034 SJ 349011 002 SJ 407074 035 SJ 351011 003 SJ 407076 036 SJ 346001 004 SJ 353038 037 SJ 348002 005 , SJ 369059 038 SJ 349001 006 SJ 383066 088 SO 384996 007 SJ 381077 089 . SO 383998 008 SJ 390080 090 SJ 397002 009 SJ 388077 091 SJ 398003 010 SJ 384061 092 SJ 390007 011 SJ 386068 093 SJ 391010 012 SJ 389064 094 SJ 396011 012-A SJ 390063 095 SJ 397013 013 SJ 393057 096 SJ 398019 015 SJ 401068 097 SJ 399019 016 SJ 412063 '098 SJ 398021 017 SJ 374049 099 SJ 402024 018 SJ 373043 101 SJ 403035 019 SJ 372037 102 SJ 396033 020 SJ 372042 104 SJ 390022 021 SJ 367035 105 SJ 383064 021-A SJ 366033 107 SJ 371042 022 SJ 368027 122 SJ 341063 023 SJ 369015 123 SJ 341036 024 SJ 365015 124 SJ 364022 025 SJ 363007 125 SJ 418083 026 SJ 362006 126 SJ 430095 027 SJ 360007 128 SJ 364024 028 SJ 362021 129 SO 330998 029 SJ 350015 131 SO 326997 030 SJ 349014 132 SJ 432099 031 SJ 340011 133 SJ 447097 032 SJ 339012 134 SJ 466092 033 SJ 334001 135 SJ 460087 -434- River Ecclesbourne Site Grid Reference Site Grid Reference No. N No. 315 SK 283529 328 SK 285512 315-A _ SK 279528 329 SK 270482 316 SK 289531 331 SK 306473 317 ' SK 280520 332 SK 307499 318 SK 284521 335 SK 291488 319 SK 289518 336* SK 293480 320 SK 276512 343 SK 295522 321 SK 287497 344 SK 288534 322 SK 294478 345 SK 290535 323 SK 285495 346 SK 289536 324 SK 290489 347 SK 285528 325 SK 303499 350 SK 285522 326 SK 313452 351 SK 335440 327 SK 319447 352 SK 284525 Rowberrow Bottom Site Grid Reference No. 206 ST 415569 226 ST 460570 227 ST 456578 228 ST 458572 229 ST 453585 230 ST 463567 231 ST 446588 -435- Minsterley Brook Catchment Soil Sample Sites Site Grid Reference No. A1 SJ 363044 A2 SJ 365042 A3 SJ 366039 A4 SJ 367038 A5 SJ 372036 A6 SJ 376034 A7 SJ 377034 A8 SJ 379033 A9 SJ 384028 A10 SJ 378034 B1 SJ 354027 B2 SJ 357025 B3 SJ 359024 B4 SJ 363023 B5 SJ 363022 B6 SJ 356020 B7 SJ 367018 B8 SJ 369017 CI SJ 326014 C2 SJ 328009 C3 SJ 331006 C4 SJ 333001 C5 SJ 334000 C6 SO 336996 C7 SO 343991 C8 SO 348989 CIO SO 354988 Cll SO 353988 CI2 SO 351988 C13 SO 335998 -436- APPENDIX 3 Reconnaissance Data -437- Minsterley Brook Stream Sediments (HNO~ attack) Cu i Pb ; Zn Cd Fe Mn Ca Mg i 01 34.8 184 384 2.4 3.48 760 - - 02 12.6 200 224 0.8 2.44 580 0.43 2766 03 50.0 1720 1760 12.1 3.16 1400 1.2 - 04 T8.0 96 144 0.8 2.88 680 - i ~~ 05 25.6 108 176 0.8 3.28 880 - 1- 06 23.2 164 224 1.2 2.72 760 - - 07 28.8 64 460 2.4 4.20 2480 - - 08 20.0 66 128 0.8 2.44 680 - - 09 19.6 3160 2760 18.7 2.80 1280 1.9 - 010 160 8400 5400 41.0 2.60 1720 5.8 - 11 89.6 6160 2200 6.4 3.28 1160 - - 12 20.8 236 276 2.4 2.84 920 - - 12a 18.0 216 300 1.6 3.24 1080 - - 13 9.6 136 248 0.8 2.20 600 - - 15 36.8 200 400 2.0 2.16 560 - - 16 15.2 92 156 1.6 1.08 640 - - 17 81.6 3400 4040 34.4 2.64 1560 - - 18a 19.2 328 439 4.0 2.28 960 0.36 2680 19 12.0 84.0 152 2.0 2.08 520 - - 21 160 6148 4319 29.6 2.40 1320 3.44 2680 22 32.0 14000 2080 28.0 2.40 1080 - - 23 60.0 1240 840 4.8 2.96. 1200 - - 24 29.6 2920 4480 29.2 2.88 1120 - - 25 16.0 2640 640 4.8 2.32 132 - - 26 40.8 10,000 7840 43.6 2.52 1800 - - 27 11.2 1480 1000 10.0 2.56 1320 - - 28 312 5680 8800 0.94 2.80 3040 7.0 - 29 21.6 1640 1800 12.8 3.44 1720 - - 30 504 15,108 20,000 164 2.00 3040 15.0 1840 31 800 22,800 28,000 236 1.56 4320 24.0 - 32 24.0 440 440 2.4 3.72 1200 - - 33 568 20800• 15,600 137 0.68 4120 26.4 — -438- Cu Pb Zn Cd Fe , Mn Ca |Mg 34 21.6 2280 2560 17.2 3.52 1360 - - 35 13.6 1640 2200 1.2 3.20 1560 - - 36 16.4 1960 280 2.0 3.20 680 - - 37 19.6 5880 4400 28.0 2.48 1960 - - 38 42.8 7360 5200 50.0 2.36 1840 - - 88 22.0 280 300 2.4 4.56 1680 - - 89 32.0 •60 204 2.0 5.20 1240 - - 90 26.4 60 172 1.2 3.28 1040 - - 91 14.0 96 64 0.8 1.76 264 - - 92 20.4 192 176 1.2 4.12 1360 - - 93 24.0 88 240 2.4 4.20 2080 - - 94 20.0 176 220 2.0 3.84 1360 - - 95 16.4 48 128 1.2 1.76 520 - - 96 17.2 92 152 2.0 2.40 520 - - 97 94.0 92 248 2.0 2.04 1320 - - 98 28.0 44 124 1.2 4.00 1000 - - 99 16.0 48 71 1.2 1.84 480 - - 101 18.0 72 116 0.8 2.40 480 - - 102 19.2 132 116 1.2 2.72 560 - - 104 11.2 576 128 1.2 2.52 400 - - 105 24.4 540 340 2.4 4.00 2360 0. 92 - 107 140 4120 5200 40.8 2.68 1520 3. 7 - 122 39.2 132 224 1.2 3.30 600 - - 123 21.2 268 248 1.2 3.80 840 - - 124 20.4 1348 2079 8.4 2.88 960 0. 24 3840 125 32.0 580 639 4.0 2.36 760 0. 52 3600 126 13.6 508 591 3.5 2.00 680 0. 48 2960 128 312 5668 6239 41.6 2.48 1600 5. 2 2920 129 28.0 108 264 2.3 3.28 680 0. 26 3560 131 55.2 1348 839 4.8 3.20 1840 0. 72 3640 132 17.2 104 208 2.0 2.40 2040 0. 56 4200 133 23.6 640 712 4.0 2.10 1400 0. 56 3400 134 38.4 680 920 8.0 2.20 1120 0. 80 3600 135 23.2 76 260 1.2 2.20 960 0. 48 2920 -439- Minsterley Brook Filtrable Metals Cu Pb Zn Cd Fe Mn Ca Mg pH 02 1.8 <2.5 116 0.4 55 7.0 58 9.0 8.3 03 2.8 6.0 250 1.0 27 23.0 83 13.2 8.3 04 2.0 <2.0 5.0 2.0 38 3.0 - - 6.1 06 1.2 0.5 11 1.2 57 115.0 - - 6.8 09 2.0 11.0 250° 1.3 29 21.5 82 13.0 8.0 010 3.0 25.0 500 3.4 66 43.0 54 8.8 8.0 028 10.7 15.0 800C 10.0 150 11.0 53 8.0 7.2 029 1.5 6.5 112 0.6 105 1.0 45 8.6 7.8 030 3.4 25.0 1900 21.5 30 41.5 58 7.4 6.9 033 3.3 19.0 1430 21.0 270 75.0 57 8.4 6.8 105 1.9 <5.0 87 0.4 115 20.0 88 13.8 8.0 107 2.3 7.5 695C 5.7 14 6.5 54 6.6 7.5 122 1.8 2.0 8.0 0.6 55 13.0 - - 7.1 124 0.8 3.5 1850C 8.3 19 37.0 45 5.1 7.7 126 2.9 13.0 150C 1.6 31 9.0 78 12.0 8.5 129 2.9 3.0 100 0.8 74 39.0 33 7.4 6.9 131 2.5 3.0 25 1.2 189 36.0 18 4.8 7.1 132 1.3 <2.5 40° 0.9 65 24.0 140 23.0 7.7 134 2.6 9.0 108 0.7 26 8.5 97 16.0 8.6 135 1.6 <2.5 50 0.9 38 13.0 106 17.4 - W. Wheel 0.9 75 762 5.5 16 54.0 63 7.4 6.6 031 4.2 105 2120 23.0 29 29 53 6.0 6.9 19 1.3 - 2.7 0.7 24 1.0 - - - 11 0.8 1.5 43 0.6 18 10 — - - Units : heavy metals ppb Ca and Mg ppm -440- Minsterlev Brook Total Exchangeable Metals Cu Pb Zn Cd Fe Mn 2 2.7 5.0 40 3.5 130 15 3 3.0 13 153 1.5 130 46 - - — 4 - - - - - — 6 - - - • 9C 2.4 16 223 1.5 150 51 10 3.2 27 420 3.3 94 35 28° 3.2 14 720 10.0 34 11 29 1.9 14 68 2.1 220 20 30 3.8 48 1880 22 58 45 33 2.9 110 1430 23 380 87 105 2.1 <5.0 37 0.5 250 62 107° 2.6 11 690 6.8 34 5 - - - 122 - - - 124° 1.0 6 2100 8.7 38 40 126C 3.2 16 150 1.1 72 11 129 2.6 6 40 0.7 540 76 - - — 131 - - - 132C 2.2 <5.0 100 0.5 130 15 134 3.3 9.0 260 5.1 85 16 135 1.8 5.0 115 0.6 86 20 S/B 1.0 90 700 5.2 30 52 31 3.9 128 2130 25 28 32 Uni ts : ppb -441 - Rowberrow Bottom Stream Sediments (HN0~ attack) Cu Pb Zn Cd Fe Mn Ca Mg 230 4.0 40 463 5.2 0.80 560 0.20 800 226 2.4 116 304 4.8 0.57 440 - - 228 8.6 4280 11400 116 0.96 560 - - 227 8.0 ,2440 10400 92 1.24 560 - - 229 28.0 8000 17600 188 1.84 1040 - - 231 20.0 3308 14399 132 2.08 1240 0.40 4800 Background Site 206 25.2 64 148 2.0 1.28 344 - - Units s ppm Ca and Fe s % - Filtrable Metals Cu Pb Zn Cd Fe Mn Ca Mg pH 230 0.5 2.5 22.0 0.7 13.0 4.0 64 4.8 8.2 226 1.0 3.5 20.2 1.0 13.5 5.5 68 5.0 8.1 228 0.6 2.5 30.0 0.7 12.5 5.0 64 5.2 7.9 227 0.6 18.0 259.2 4.3 35.5 7.5 42 6.4 7.9 229 2.4 23.0 310 4.8 80.0 37.5 40 5.4 7.8 231 0.4 5.0 80.0 1.6 9.5 2.5 44 6.6 8.0 206 1.6 2.5 66.0 1.9 18.5 16.5 — — — Total Exchangeable Metals 230 226 0.8 2.5 40 1.6 140 23 228 1.5 19 80 2.0 170 19 227 2.4 172 520 8.2 440 63 229 8.8 500 1840 26 1550 460 231 2.3 70 360 6.2 220 28 206 1.1 5.0 26 2.4 110 18 Units s heavy metals : ppb, Ca and Mg : ppm -442- River Ecclesbourne Stream Sediments - (HNO^ attack) Cu Pb Zn Cd Fe Mn 315-A 68 538 512 10.8 5.48 3280 316 13.* 2 398 470 6.4 1.30 340 317 30.0 880 248 5.6 2.96 840 318 91.2 19200 1760 32.0 2.56 1560 319 6.8 760 168 2.0 1.20 300 320 17.6 592 268 3.6 3.40 2080 321 26.8 9600 1080 12.4 2.16 680 322 6.4 536 280 4.4 5.00 1240 323 14.0 712 90 1.2 1.88 480 324 29.6 3600 1360 16.0 2V60 920 325 28.4 1560 544 5.6 2.84 1000 326 16.4 116 332 4.6 1.54 420 327 28.8 1000 520 4.0 3.44 960 328 40.0 10,000 1360 19.2 2.00 1000 329 44.8 440 192 3.6 4.36 840 331 26.0 56 87 1.6 2.00 400 332 4.8 64 112 2.0 0.64 104 335 30.4 600 200 3.2 3.20 1760 336 62.8 5120 600 6.4 4.08 520 343 8.8 575 188 2.6 1.36 312 344 49.6 3480 1640 26.4 2.08 760 345 47.2 272 200 3.2 3.48 480 346 47.6 4000 1760 28.0 1.96 640 Units s ppm Fe s % \ -443- River Ecclesbourne Filtrable Metals Cu Pb Zn Cd Fe Mn Ca Mg pH 315 2.5 3.5 88 4.0 15 290 49 6.2 7.0 317 3.9 7.0 23 1.2 225 170 52 8.4 6.8 318 4.6 5.0 111 2.0 50 130 78 9.8 7.2 319 0.8 4.5 18 1.0 39 21 34 9.7 7.2 320 1.3 5.5 29 1.2 100 50 36 8.0 6.8 321 2.0 • 5.5 46 0.9 75 80 54 9.0 7.1 324 1.8 5.0 38 0.8 55 80 52 8.8 7.0 325 2.0 4.0 35 1.0 75 105 52 8.8 6.8 327 1.8 3.5 28 1.7 60 80 60 11.0 7.0 328 2.7 5.0 74 1.3 55 90 66 9.0 7.0 331 1.6 <2.5 16 0.7 70 38 65 12.6 7.2 332 0.9 <2.5 28 1.6 31 18 43 11.8 6.8 River Ecclesbourne Total Exchangeable Metals Cu Pb Zn Cd Fe Mn 315 5.6 27.5 113 4.4 600 375 316 1.2 2.0 12 0.5 155 20 317 6.7 25.0 44 3.0 606 191 318 7.6 29.5 145 3.2 230 135 319 1.4 22.5 31 1.1 390 50 320 3.5 67.5 47 1.4 1525 162 321 3.2 22.3 69 1.6 386 106 324 3.0 17.5 59 1.4 430 122 325 2.9 14.0 49 1.3 334 127 327 3.0 13.5 51 1.7 343 117 328 4.9 23.5 101 2.4 250 108 331 2.9 7.0 40 2.1 329 56 332 1.0 4.0 20 1.0 190 16 Units heavy metals s ppb Ca and Mg t ppm -444- APPENDIX 4 -445- Table A4.1 Chemical Data for Soil Samples from the Minsterley Brook Catchment Traverse A 0-15 cm Cu . Pb Zn Cd Fe • Mn Ca Mg All 16.0 160 192 1.6 2.8 600 4760 2720 A21 22.8 264 352 2.0 2.8 800 2920 3000 A31 26.0 540 296 2.0 3.2 920 4440 3720 A41 28.0 880 332 2.4 2.84 840 5440 3760 A51 12.8 164 176 1.2 2.28 1160 3160 2600 A61 16.0 300 188 1.6 3.08 1320 2680 3680 A71 11.6 140 113.6 1.2 2.64 760 2240 3120 A81 18.8 296 364 1.6 2.64 1040 3280 3000 A91 13.6 240 144 1.2 2.72 480 3280 3040 A101 120 28800 9000 100 1.88 6000 35.6% 600 30-45 cm Cu Pb Zn Cd Fe Mn Ca Mg A12 8.8 64 113.6 0.8 2.28 360 2480 2280 A22 53.6 184 280 2.0 3.04 1480 2080 3360 A32 20.6 260 180 0.8 3.24 840 2520 3880 A42 23.2 880 348 4.0 3.20 840 6000 3800 A52 13.6 144 144 1.2 3.08 1600 3080 3520 A62 17.2 136 124 0.8 3.80 840 2200 4120 A72 17.6 68 97.2 1.2 4.00 320 2720 4160 A82 15.6 116 228 1.6 3.44 1200 2040 4160 A92 13.2 80 92 0.8 3.44 480 1880 4400 -446- Table A4.1 contd. Traverse B 0-15 cm Cu . Pb Zn Cd Fe Mn Ca i Mg Bll 13.2 140 180 1.2 3.48 680 2320 3280 B21 27.2 400 368 2.4 3.36 1000 4600 4040 B31 19.2 104 184 1.6 3.88 880 4400 3760 B41 140 108 116 1.2 3.08 400 3320 3640 B51 228 15600 13000 91 .6 2.56 2440 66000 1800 B61 24.0 400 272 1.6 3.72 920 14000 2600 B71 16.0 272 128 0.8 3.00 640 14600 1868 B81 16.0 440 196 0.4 2.52 400 12360 1400 30-45 cm Cu Pb Zn Cd Fe Mn Ca Mg B12 12.0 36.0 132 0.8 4.2 520 1600 4000 B22 20.0 200.0 244 2.0 3.60 1240 2800 4400 B32 16.0 60.0 144 1.2 3.76 640 4360 3840 B42 11.2 80.0 96 1.2 3.08 320 1760 3640 B52 272 20000 7240 50.4 3.28 3040 76000 1932 B62 16.0 172 148 1.6 3.64 920 9600 2668 B72 20.0 132 108 0.8 4.64 280 10600 2668 B82 8.0 400 88 0.4 3.64 680 5800 1868 -447- Table A4.1 (contd.) Traverse C 0-15 cm Cu Pb Zn Cd Fe Mn Ca Mg Cll 10.4 68 112 0.8 2.44 800 1560 2800 C21 11.2 140 128 0.8 1.72 400 560 2080 C31 12.0 188 244 1.2 2.44 288 2440 2240 C41 124 5440 3520 29. 2 3.56 1360 6880 2680 C51 196 1.04% 3000 28.0 2.08 1880 7400 1680 C131 23.2 528 136 1.2 3.16 800 3480 2720 C61 17.6 376 116 1.2 3.08 880 2480 720 C71 15.2 268 124 0.8 2.92 720 2080 3480 C81 20.0 296 348 2.0 2.64 680 3240 2480 C121 19.2 480 308 2.8 2.04 280 4280 1720 C101 13.2 1040 208 2.4 0.96 180 3000 760 30-45 cm Cu Pb Zn Cd Fe Mn Ca Mg C12 13.6 84 128 2.0 3.32 920 1400 3720 C22 11.2 32 85? 0.8 2.6 560 320 3800 C32 10.0 80 156 1.6 2.92 320 1360 3520 C42 24.0 2400 768 6.0 3.24 2000 2800 3000 C52 C132 22.6 548 128 0.8 3.12 640 2880 2920 C62 19.6 180 97 1.2 3.36 520 640 3200 C72 16.8 300 124 1.2 3.68 880 680 3880 C82 20.0 136 176 0.8 3.64 720 1000 4480 C122 13.6 108 132 1.6 3.12 200 1400 3600 C102 6.4 392 204 1.2 2.96 720 1360 1880 Uni ts i ppm ; Fe t % -448- Table A4.2 Heavy Metals in Bank Soils from Mainstream Sites - Minsterley Brook Cu Pb Zn Cd Fe Mn Ca Mg 129/1 48.8 400 560 5.2 3.68 1320 0.14 3400 129/R 33.6 480 468 3.2 4.24 1280 0.18 4320 33/R 116 6600 4240 44.4 2.6 1640 3.4 2080 31/L 228 6000 13200 88 3.88 1880 1.92 4320 31/R 80.8 5040 1480 6.8 3.72 1560 0.32 3920 30/L 40 80 204 1.2 4.64 280 0.18 1352 30/R 168 14400 7600 48.8 3.48 2080 1.12 3360 28/L 384 8400 7400 62.0 3.40 2440 5.12 3760 28/R 208 6800 7200 60.0 3.2 2360 5.04 3400 107/L 164 10800 4760 37.6 2.68 1840 4.8 2132 107/R 132 8000 4840 36.0 2.92 1880 4.2 3640 010/L 152 286400 9080 82 2.16 3160 12.4 2560 010/R 94.8 10000 3800 40.8 2.56 2000 5.32 3800 009/L 80.0 12000 4160 34.0 2.52 1360 4.00 3600 009/R 128 24000 3320 28.4 2.4 2240 2132 03/L 50.0 2520 1680 10.8 2.56 1120 1.08 3600 03/R 36.0 920 904 5.6 3.04 1080 0.65 4360 126/L 28 1240 976 5.6 2.72 1040 0.16 2400 126/R 44 1600 1112 7.2 2.84 1040 0.18 2600 134/L concrete embankment 134/R 28 920 712 1 4.4 2.52 | 920 8.6 2468 Units : ppm 5 Fe and Ca : % L t signifies left hand bank facing upstream R : " right " •• -449- Table A4.3 Heavy Metals in Bank Soils from Tributary Sites - Minsterley Brook Cu Pb Zn Cd Fe Mn . Ca Mg 029/L 18.0 840 176 1.2 3.60 920 0.08 3840 029/R 30.8 2440 800 4.8 3.44 1160 0.32 3600 Sn/Bch 252 14% 3200 18.8 2.00 1560 1.6 1360 Dump 105/L 91.2 32000 11120 100 2.12 3080 21.2 27 20 105/R 216 28000 9160 92 1.72 3600 17.0 1268 02/L 20.0 1600 248 0.8 2.16 760 0.79 2268 02/R concrete erribankmen t 132/L 28 240 420 2.4 3.6 1280 0.13 3532 132/R 60 200 588 1.6 3.52 960 0.18 2600 124/L 23.6 2480 4040 20.0 3.28 2800 0.23 3800 124/R 21.6 1440 1400 9.6 3.28 440 0.44 3680 L t signifies left hand bank facing upstream R t " right •• Units s ppm ; Fe and Ca t % -450- Table A4.4 Heavy Metals in Bank Soils from Mainstream Sites - River Ecclesbourne Site Cu Pb Zn Cd Fe Mn Ca Mg 352R 96 5600 2960 42.8 2.84 1080 - 1668 352L 100 7 200 2800 38.4 4.04 1480 6.32 1600 318R 120 4400 2520 40.8 3.24 1152 10.00 1732 318L 76 26400 1840 17.6 3.54 860 1.80 1132 328R ------ 328L ------321R 56 3200 1276 17.6 2.88 1160 20.00 1200 321L 48 2000 988 9.2 4.32 1328 - 1196 336R 48 2400 920 9.2 3.00 1240 2.14 1132 336L 44 1600 744 7.6 3.32 1048 1.64 1264 325R 44 1480 692 9.2 3.44 1400 1.52 932 325L 56 1120 800 7.6 7.64 1680 1.12 1064 327R 36 1360 560 6.0 3.24 1080 1.34 868 327L 44 1360 684 8.4 3.52 1480 1.34 1600 351R 40 1120 548 6.8 3.76 1640 1.28 868 351L 48 1200 600 9.2 3.64 1320 1.70 2268 Uni ts i ppm ; Ca and Fe t % Table A4.5 Heavy Metals in Bank Soils from Tributary- Sites - River Ecclesbourne Site Cu Pb Zn Cd Fe Mn Ca Mg 322R 52 560 168 3.2 5.24 1880 0.44 932 322L 40 400 200 4.0 4.88 1412 0.64 996 331R 20 400 140 3.2 1.76 320 0.45 932 331L 32 1000 100 3.2 2.56 2600 0.75 1396 Units s ppm ; Ca and Fe % Table A4.6 Sunvmarised Sediment Data for Minsterley Brook Table- A4 . fe (contd,) Cd Fe Mn Ca Mg Stat. Cu Pb Zn Cd Fe Mn Ca Kean 29.4 298 393 3.0 3.8 Mg 870 0.28 3602 Mean 101 2207 2440 S.D. 5.1 58 103 0.6 0.54 95 18.5 2.79 1353 1.90 3469 0.14 593 S.D. 16.6 369 757 C.V. 17.3 19.6 26 20 20 6.8 0.13 276 0.35 740 11V 50 16.5 C.V. 16.4 16.7 31 KdX. 39.2 400 584 4.0 4.96 36.6 4.6 20.5 18.4 21.3 3160 0.56 4160 Max. 125 2720 3840 Min. 24.0 224 300 28.8 3.80 1760 2.44 4320 2.4 3.40 760 0.20 2532 Min. 74 1720 1520 10.4 2.52 1040 1.32 2480 Mean 1103 30660 26433 206 0, ,81 6300 29. ,3 1080 S.D. Mean 58 1418 1643 10.6 2.95 715 19659 15222 122 0. ,19 764 2. .1 920 1351 1.36 3723 C.V. S.O. 15 148 177 2.1 0.19 65 64 58 59 24 12.1 7 85 C.V. 286 0.20 647 hax. 2400 68000 26 10.4 10.8 19.8 6.6 21.1 14.5 17.4 46400 384 1. .12 7200 31. .6 3000 Max. 85 Kin. 256 4360 1600 1880 14.1 3.27 1907 1.72 421B 7000 56 0. .47 5000 25, .0 440 Min. 48 1200 1392 8.0 2.80 1040 1.17 2320 Mean 983 24117 29937 239 1, ,95 4045 17. .1 1733 Mean 25 699 766 S.D. 439 2773 9569 79 0..3 9 5.1 2.24 968 0.55 3264 231 3, .26 233 S.D. 8.8 107 47 C.V. 44.7 11.5 32 33 0.6 0.07 214 0.06 521 20 5.7 19, .1 13.4 126 C.V. 34.8 15.3 6.0 Max. 1600 28000 25600 360 11.5 3.2 22 10.2 16 2. .80 4400 21, .0 2000 Max. 38 Min. 588 20000 19600 840 820 5.6 2.32 1360 0.60 3800 144 1. .64 3800 11, .0 1400 Min. 16 568 688 4.0 2.12 760 0.48 22b0 Mean 459 22467 18100 135 2, .43 3393 12, .8 2347 Mean S.D. 152 23 556 745 4.8 2.27 1200 10929 3769 22.7 0,.2 0 252 1.,5 2 370 S.D. 0.77 3251 C.V. 33 4.9 124 61 1.5 0.09 370 49 21 16.9 8, .1 7.4 11, .9 15.8 134 C.V. 0.49 575 21 22 8.2 30.7 4.0 31 Max. 720 44000 24400 176 2, ,80 3800 15, .4 2760 64 17.7 Max. 30 760 808 7.0 2.40 1960 Min. 292 10800 12800 104 2, .16 3080 11, .0 1720 Min. 1.76 4000 16.8 400 672 2.4 2.16 920 0.20 2120 Mean 297 9266 6900 75 2, .92 2233 6. 26 3027 S.D. 88 4474 1913 15.6 0,.1 6 191 1.5 2 581 C.V. 29.5 48.3 21 21 5. .6 8.6 24 19.2 Max. 404 18000 11200 88 3, .24 2640 8.4 3800 Min. 184 5600 6560 48 2. .72 2040 5. 04 2400 Units i ppm Mean 226 5420 5430 42.9 2, .76 1350 3. 63 2893 S.D. I Fe and Ca, % 106 1406 891 7.9 0. .07 71.4 0.2 7 677 C.V. 47 26 16.4 18.6 2. .7 5.3 7. 44 23 Max. 408 7640 6600 56.0 2. .88 1440 4. 00 3680 Min. • 152 4040 4240 35.2 2, .68 1280 3. 60 2120 Mean 134 3407 4433 35.4 2. ,81 1393 3. 26 3358 S.D. 22.4 441 503 6.9 0, ,09 137 0.4 9 495 C.V. 16.7 12.9 11.3 19.5 3. ,2 9.9 15 14.7 *ax. 160 4000 5200 41.2 2. ,92 1600 3. 88 3800 Min. 104 2560 3640 22 2. ,64 1200 2. 56 2468 -452- Tablo A4.7 Summarised Sediment Data for Minsterley Brook Tributaries Mn Ca Mg Site Stat. Cu Pb Zn Cd Fe ' 567 0.21 3415 Mean 13.8 248 196 1.3 2.18 84.59 0.02 151.44 S.D. 1.65 42.77 26.63 0.71 0.41 18.8 14.9 9.5 4.4 02 C.V.% 12.0 17.2 13.6 54.6 3.04 720 0.25 3600 Max. 16.0 320 252 2.0 1.84 480 0.20 3200 Min. 11.6 200 172 0 0.62 3980 25.1 528 335 2 .7 3. 29 1750 Mean 703.92 0.6E 1058.87 S.D. 6.43 153.15 93.23 0 .52 0.3 6 40.2 82.9 26.6 C.V.% 25.6 29.0 27.8 19 .3 10. 9 105 2520 2.0 5400 Max. 36.0 720 488 3 .6 3. 88 880 0.4 2920 Min. 19.2 304 244 2 .4 2. 92 1368 0.66 3818 Mean 30.7 1896 1850 14.0 3.42 248.39 0.45 844.34 S.D. 10.74 477.06 343.93 2.54 0.20 5.8 18.2 68.2 22.1 029 C.V. 35 25.2 78.9 18.1 2000 18.0 3.72 1840 1.5E 4720 Max. 46.4 2800 0.26 2680 Min. 20.0 1440 . 1572 10.4 3.16 1120 0.3E 3766 Mean 18.5 85 174 1.6 2.45 1808 0.05 769.25 S.D. 4.71 31.33 18. 0.84 0.24 416.77 23.1 13.2 20.4 C.V. 25.5 36.9 10.3 52.5 9.8 332 2520 0.44 4680 Max. 27.0 124 204 3.2 2.88 1360 0.32 2680 Min. 13.2 48 156 0.8 2.16 Units « ppm, Ca and Mg i * -453- in kinstvrlLX Tabji- A4.B BrooK Mn Ca Mg pH Site Stat. Cu Pb Zn Cd Fe 58 31 7.0 7.2 Mean 3.0 4.8 23 1.3 311 31.0 3.0 0.51 0.32 S.D. 0.91 1.72 10.3 1.4 36.4 54 9.7 7.2 4.4 C.V. 30 36 45 11.5 11.7 129 120 34 7.6 7.7 Max. 4.1 7.0 34 4.4 360 28 26 6.4 6.8 Min. 1.5 2.5 8 0.2 245 67 42 7.2 7.3 Mean 3. ,9 18.6 1061 17 210 27 10.4 0.9 0.26 S.D. 1.,2 4.6 598 8.7 51.6 41 25 12.9 3.6 C.V. 30. ,2 25.0 56.4 51 25 33 115 56 8.4 7.6 Max. 6. ,2 25 1850 28 273 32 26 5.6 6.9 Min. 2. ,5 10 260 6.2 140 47 6.2 7.5 3.6 57 1432 14.1 94 66 Mean 9 0.5 0.29 0.6 12.8 463 4.5 49 16 S.D. 19.2 7.6 3.9 17.6 22.6 32 32 53 25 31 C.V. 57 7.0 7.8 4.4 69 2069 22 178 88 Max. 41 32 5.4 6.9 Min. 2.5 32 695 8.3 34 63 47 6.9 7.6 Mean 3. 7 44 1325 13.3 124 15 5 0.4 0.31 S.D. 0. 7 21.8 361 2.7 50 24 11 6.0 4.1 C.V. 19. 4 50 27 20 40.6 30 85 54 7.5 8.0 5. 2 85 1860 17.6 210 Max. 44 38 6.2 7.0 Min. 3. 0 20 890 10.0 60 34 46 7.2 7.5 Mean 3.7 27 667 7.4 193 9.5 6.7 1.0 0.26 S.D. 1.1 14 226 1.9 151 15 14 3.5 C.V. 30.2 50 34 26 78 28 28 54 54 8.6 7.8 Max. 5.2 54 1020 9.8 460 23 36 5.8 7.0 Min. 2.5 15 360 4.0 65 24 47 6.3 7.6 Mean 3.0 21 757 6.1 159 9.3 7.2 0.6 0.22 S.D. 1.3 12 233 1.3 144 38 15 10.4 2.9 43 55 31 22 91 107 C.V. 37 58 7.6 7.9 5.5 4.0 1175 8.2 413 Max. 15 36 5.6 7.2 Min. 2.0 8.8 470 3.8 30 35 54 7.6 7.8 Mean 3.5 18.6 596 4.1 138 15 6.9 1.0 0.08 S.D. 1.7 16 111 1.0 204 43 12.8 12.7 1.0 C.V. 47 86 19 25 148 10 56 66 8.8 7.9 Max. 7.0 54 727 . 5.3 590 12 44 6.4 7.7 Min. 1.9 8 401 2.7 21 127 57 79 11.0 7.8 Mean 3.0 12.8 237 1.8 134 17 10 0.9 0.27 S.D. 1.3 10.1 103 0.7 105 29 13 8.3 3.5 C.V. 45 79 44 37 09 420 80 100 12.0 8.2 Max. 5.4 35 400 3.0 29 32 66 9.4 7.5 Min. 1.8 5 150 1.0 44 82 11.9 8.0 2.6 6.2 358 1.3 50 Mean 15 7.2 0.7 0.31 S.D. 0.4 2.5 25 0.6 26 53 35 8.8 5.6 3.9 03 C.V. 17 40 36 45 105 75 96 13.0 8.3 Max. 3.2 8.5 202 2.3 29 30 74 11.2 7.5 Min. 2.0 2.5 130 0.7 11.0 8.2 7.0 119 1.0 89 34 79 Mean 2.5 6.0 0.8 0.40 S.D. 0.7 3.3 19 0.4 88 22 99 64 7.6 7.4 4.9 126 C.V. 29 48 16 40 280 67 88 12.0 8.7 Max. 4.0 12.0 151 1.7 24 13 72 30.0 7.6 Min. 1.8 3.0 89 0.5 12.5 8.2 79 0.7 79 31 86 Mean 2.5 6.6 1.4 0.29 17 0.3 65 21 8.7 S.D. 0.6 3.1 11.3 3.5 46 21 48 82 67 10.0 134 C.V. 23 96 14.8 8.4 3.6 11.8 303 2.2 218 63 Max. 5.0 72 11.0 7.7 Min. 1.8 2.5 62 0.4 20 Units i Heavy metals ppb Ca and Mg, ppm -454- TabjP A4.9 Surprised for FiltrabTe Metals in Minsterlej; DrooH Tributaries pH Cd Fe Mn Ca He Site Stat. Cu Pb Zn 36.7 7.4 7.88 2.9 6.0 0.5 76.5 9.1 , Mean 2.1 3.06 7.45 1.23 0.39 0.64 0.17 1.44 0.41 22.13 S.D. 34 20.3 16.6 4.9 30.5 5.9 24.0 82.0 28.9 02 C.V. 15 46.5 9.6 8.5 3.3 3.0 7.7 1.4 105 Max. 41 6.6 28 5.8 7.5 Min. 1.2 2.5 4.0 0.2 90 13.0 7.67 5.2 17.0 0.5 220 83.5 Mean 2.4 6.26 0.85 0.32 2.27 8.94 0.13 133.42 25.04 S.D. 0.84 7.0 4.2 52.6 0.3 60.6 30 6.6 105 C.V.* 35 43.7 102 14.2 8.3 36.0 0.7 430 110 Max. 3.7 9.0 84 12.1 7.3 Min. 1.5 2.5 8.3 0.3 83 39 214 28 40 9.1 7.55 Mean 2.4 19.7 117 1.2 129.74 13.5 4.96 1.31 0.33 S.D. 1.20 13.6 80.55 0.44 60.6 48.2 12.4 14.4 4.4 C.V. 50 68.8 68.8 36.7 029 500 43 46 12.0 7.9 Max. 4.5 47.0 259 1.9 130 12 32 8.2 6.9 Min. 1.4 10.0 40 0.6 7.88 0.4 148 67 117 22.6 Mean 2.4 3.4 31.3 0.13 0.17 66.08 37.87 18.09 5.89 S.D. 0.77 0.95 5.28 1.6 46.7 42.5 44.7 56.5 15.5 26.1 132 C.V. 32.1 27.9 8.0 5.0 20.0 0.7 270 120 138 33.2 Max. 3.8 86 15.8 7.7 Min. 1.7 2.5 7.0 0.2 75 25 Units i heavy metals, ppb Ca and Mg, ppm -455- •j R_A 4.-.L2 Su-rarist-d I)at a_lotJLc:I*l_J- Ml''1 Ali-LD Hi nsu-rlev BrooV Fe Mn Site* Stat, Cu Pb Zn Cd 152 Mean 3.9 16.3 38.7 1.9 837 92 S.D. 1.4 10.5 1G.8 1.7 336 60.5 C.V. 35.9 64.4 43.4 89 40.1 129 1360 307 Hax. 5.8 37 58 5.5 348 75 Hin. 2.0 6 16 0.3 Kc?an 4.9 59 1172 18.9 576 121 S.D. 1.6 43.8 583 8.9 225 54 44.6 33 C.V. 32.6 74.2 49.7 47 39.1 1023 212 Hax. 7.3 155 1951 30.1 273 55 Hin. 2.7 29 335 7.6 5.4 175 1602 17.4 264 88 1.9 115 375 3.2 186 33.5 35.2 65.7 23.4 18.4 70.5 38.1 8.8 392 2146 23.4 554 145 3.3 83 1015 12.8 79 44 5.8 169 1533 15.7 370 95 3.12 194 254 2.4 344 46 54 114 16.5 15.5 93 48 12.6 585 1699 18.5 940 168 3.4 31 1165 12.4 12.0 47 Hean 5.9 145 852 10.6 479 70 S.D. 3.6 158 98 2.0 481 51 73 28 C.V. 61 109 11.5 18.9 100.4 Max. 11.5 404 1050 14.0 1250 159 Min. 2.8 23 736 7.9 98 30 Mean 5.0 141 988 8.9 551 79 S.D. 3.4 169 162 2.8 658 82.4 104 107 C.V. 68 120 16.4 31.5 119 Max 10.5 423 1194 14.2 1693 227 Min. 2.2 12 804 6.6 44 18 Mean 5.0 80 746 6.6 444 79 S.D. 3.16 107 238 2.52 521 59 117 74.7 10 C.V. 63.2 134 31.9 38.2 Max. 11.4 314 1220 11.1 1550 200 Min. 2.1 16 486 3.9 73 25 Mean 4.5 68 3B5 3.1 566 125 S.D. 2.83 8.21 249 2.47 462 63 09 C.V. 62.9 12.1 64.7 79.7 81.6 50.6 Max. 10.0 265 930 8.6 1510 246 Min. 2.3 11 206 1.5 229 64 99 Mean 3.4 24 211 3.4 355 30 S.D. 1.14 18.7 26 2.6 245 69 30.3 03 C.V. 33.5 77.9 12.3 76.5 895 140 Max. 5.7 65 260 9.0 200 63 Min. 2.1 10 183 1.5 74 Mean 3.3 20 155 1.6 321 1.3 14.5 25 0.43 223 33.6 S.D. 45.4 126 C.V. 39.4 72.5 16.1 26.9 69.5 6.0 52 203 2.5 810 138 Hax. 23 Hin. 2.1 10 119 1.1 150 65 Hean 3.0 14 103 1.6 245 0.49 3.4 20.6 0.63 88 17.1 S.D. 26.3 134 C.V. 16.3 24.3 20 39.4 35.9 4.0 19 131 2.5 373 90 Hax. 35 Min. 2.5 8 72 0.9 115 Units i ppb. -456- Tablf A4.ll Surmari sod Data for Total Exchangeable Metals in Minstcrley Brook Tributaries Mn Site Stat. Cu Pb Zn Cd Fe 3.0 6.7 11.5 0.7 232 25.1 Hean 11.53 S.D. 0.85 1.85 7.35 0.47 106.75 45.9 C.V. 28.3 27.6 63.9 67.1 46.0 02 50 4.2 10.5 27.7 1.6 <425 Max. 16.6 Kin. 2.4 5.4 6.8 0.3 101 151.5 Mean 3.6 11.7 76. 0 1.0 570 58.1 S.D. 1.04 3.50 10. 26 0.41 262.69 46.1 38.3 105 C.V. 0.3 29.9 39. 5 41 40. 7 1.7 1090 232 Max. 5.2 18.0 54 Min. 2.2 7.5 14. 3 0.5 220 111 Mean 3.5 109 211 2 .4 801 S.D. 2*31 129.4129^48 163.43 1.61 .65 709.55 120.39 88.6 029 C.V. 66 118.8 77.5 68 .7 " - 108.5 Max. 7.7 66 494 5 .8 2220 363 Min. 1.6 1.6 91 0 .9 235 32 Mean 3 .5 6.4 55.7 0.7 567 152 S.D. 1 .16 1.88 7.46 0.15 331.43 90.61 132 C.V. 33 .1 29.4 1.8 21.4 58.5 59.6 Max. 5 .A 10.0 25.8 0.8 1050 280 Min. 2 .4 5.0 8.0 0.4 185 62 Units i ppb -457- Table A4.1 ? Surprised Sedinfnt Data for the River Ecci r.'.hou r m- Si te Cu rb Zn Cd Fe Mn Ca Kg 352 Mean 76.5 4432 1947 25 .9 21695 797 86700 3358 S.D. 18.33 923.21 215.65 1 .99 519.38 207.24 37859 230.67 C.V. 23.9 20.8 11.1 7 .7 2.4 26.0 43.7 6.9 Max. 104 5600 2200 27 .6 22600 1160 110000 3720 Min. 60 3080 1640 22 .8 21200 560 10200 3080 31 f? Mean 74.2 20666 2046 28 .5 23600 750 70960 2811 S.D. 14.70 16794 368.71 4 .69 1752.7 97.78 10180.7 234.24 C.V. 19.8 81.3 18.0 16 .5 7.4 13.0 14.4 8.3 Max. 91.0 52000 2560 35, .2 25600 880 81200 2960 Mi*h. 56.0 6320 1680 23, .2 20400 640 57600 2400 328 Mean 45.8 10485 1544 19. 6 22853 932 31590 1780 S.D. 5.74 3423.99 265.15 2. ,03 4224.63 124.61 1249 144.78 C.V. 12.5 32.7 17.2 10. ,4 18.'5 13.4 4.0 8.1 Max. 54 15200 2040 23. 2 30800 1120 33150 2000 Min. 40.0 6000 1305 17. 6 19920 793 30000 1623 321 Mean 23 6393 894 10. 4 17833 583 12960 1070 S.D. 2.93 1707.3 128.64 1.6 0 2347 132.9 1512 33.2 C.V. 12.7 26.7 14.4 15. 4 13.2 22.8 11.7 3.1 Max. 27.0 9600 1080 12. 4 20600 760 14000 1120 Min. 19.0 4880 736 8. 4 14800 400 10400 1040 336 Mean 17 .8 3416 543 5.6 17066 680 6520 839 S.D. 2 .32 1156 115.9 1.48 1782 158 821 83.9 C.V. 13 .0 33.8 21.3 26.4 10.4 23.2 12.6 10.0 Max. 20 .0 5360 680 7.6 19200 920 8000 960 Min. 14 .0 2040 428 4.0 14400 560 5600 760 325 Mean 25 .2 1486 569 6.2 25500 980 5083 1184 S.D. 3 .92 334 71 1.1 2275 236 796 104 C.V. 15 .6 22.5 12.5 17.7 8.9 24.1 15.7 8.8 Max. 30 .0 1840 656 7.6 28000 1320 6000 1264 Min. 21, .0 1040 464 4.8 21600 640 4000 1000 327 Mean 23.2 753 411 3.8 22600 1027 3000 940 S.D. 3.48 167 86.3 1.45 3611 360 358 182 C.V. 15.0 22.2 21.0 38.2 16.0 35.1 11.9 19.4 Max. 28.0 1000 536 5.6 28800 1480 3400 1280 Min. 20.0 616 320 2.0 20000 640 2400 800 351 Mean 24.8 820 441 4.2 27033 1019 3089 957 S.D. 2.93 75 30.7 0.85 1977 179 211 63.3 C.V. 11.8 9.2 7.0 20.2 7.3 17.6 6.8 6.6 Max. 29.0 920 -4B8 5.6 29200 1229 3280 1024 Min. 22.0 720 408 3.2 24400 760 2700 880 I'ni ts f ppm -458- Surm.a ri sed s^^nnl Data for River Led t-sbourng Tri butaries Fe Mn Ca Mg Site Cu Pb Zn Cd 322 4.11 1347 0.47 1665 Mean 37.7 347 295 4.3 0.58 334.4 0.31 594.91 S.D. 4.87 47.85 74.20 0.85 14.11 24.8 66.0 35.7 C.V. 12.89 13.8 25.2 19.8 5.12 2040 1.12 2800 Max. 46.0 420 456 4.4 3.20 1080 0.20 1080 Min. 31.2 288 240 3.2 331 369 0.29 1106 18.4 75 90.5 2.1 1.47 Mean 93.91 0.34 157.49 6.81 38.12 30.10 0.88 0.43 S.D. 25.4 117.2 14.2 37.0 50.8 33.3 41.9 29.3 C.V. 520 0.96 1400 28 160 156 4.0 2.00 Max. 1.00 260 0.09 960 Min. 11.2 56 64 1.6 347 720 12.5 3233 78 3849 1990 28.7 1.90 Mean 0.25 256.1 1.12 87.7 10.1 345.6 302.4 3.2 S.D. 13.2 35.6 9.0 2.7 13.0 9.0 15.2 11.2 C.V. 1160 14.0 3360 94 4480 2560 34.4 2.20 Max. 1.40 320 11.0 3080 Min. 66 3600 1680 24.8 315 5.07 2616 2.66 1517 69 1056 707 12.9 Mean 0.45 364.5 1.06 249.5 S.D. 5.2 285.4 162.6 2.10 8.9 13.9 39.9 16.5 C.V. 7.5 27.0 23.0 16.3 5.72 3280 4.0 1920 Max. 76 1280 920 16.0 4.56 2200 0.68 1268 Min. 62 538 512 14.4 Units » ppm Ca and Mg « * -459- Table A4.14 Su-.-.arisrd Data for F i ltjraM_£_MM_aJ r _ij5_Hi_lIlL Lccl esbournc Ca pH Si to Cu I'b Zn Cd Fe Mn 35? 147 159 87.7 10.0 7.53 Moan 2.8 13.3 92 1.1 0.15 53.5 0.7 116 84 8.2 1.08 S.D. 1.06 12.36 2.0 63.6 78.9 52.8 9.4 10.8 C.V. 37.9 93.0 58.2 11.2 7.7 Max. 4.6 35 190 2.2 363 263 100 76 8.2 7.3 Kin. 1.4 4.0 36 0.2 50 75 318 7. .37 91 1..5 124 91 75 9. 5 Mean 6.3 11.0 .07 81.8 0..9 2 42.1 39.8 10.5 1.6 2 0. S.D. 2.65 13.76 0.,9 42.1 125.1 90 61. .3 34.0 43.7 14.0 17. 1 C.V. 11. 3 7. ,4 Max. 10.0 38 250 3, .0 200 160 89 66 7. 6 7. .2 Min. 2.7 2.5 32 0..6 84 48 328 68 10.3 7.56 Mean 4.4 6.4 59 1.0 69 58 8.4 1.76 0.17 S.D. 1.01 2.38 46 0.35 31 22 12.4 17.1 2.3 C.V. 23.0 37.2 78.0 35.0 44.9 37.9 78 12.0 7.9 Max. 5.6 10.0 138 1.4 105 82 32 60 8.0 7.4 Min. 3.3 4.0 28 0.6 40 321 57 60 10.4 7.57 Mean 3.5 7.9 43 1.1 82 20.7 5.7 1.86 0.19 S.D. 1.44 5.19 40.1 0.59 48 36.3 9.5 17.9 2.5 C.V. 41.1 65.7 93.3 53.6 58.5 68 13.2 7.8 Max. 5.8 18.0 122 2.0 165 80 32 52 8.0 7.3 Min. 1.8 3.5 15 0.5 24 336 10.8 7. 53 3.4 10.5 36.8 1.2 96 46 56 Mean 2.04 0.1 9 1.58 13.9 39.2 0.9 0 73.4 14.5 6.2 S.D. 2. 5 46.5 132.4 106.5 75. 0 76.5 31.5 11.1 18.9 C.V. 7. 8 6.4 39 116 2. 9 230 65 64 13.2 Max. 8.0 7. 3 Min. 1.8 3.0 13 0.5 39 23 46 325 10.7 7.62 3.3 5.4 31.7 0.7 100 44.5 57 Mean 2.33 0.29 0.95 2.91 32.5 0.24 56 18.6 14.8 S.D. 21.8 3.8 28.8 53.9 102.5 34.3 56.0 41.8 26.0 C.V. 14.0 8.2 Max. 4.6 11.0 96 1.1 195 75 86 46 7.3 Min. 1.9 3.0 10.0 0.5 31 27 8.0 327 12.7 7.65 3.0 5.1 30 0.7 123 44 58 Mean 2.47 0.23 0.67 2.01 28.9 0.23 69.9 19.4 3.7 S.D. 19.5 3.0 C.V. 22.3 39.4 96.3 32.9 56.8 44.1 6.4 3.5 8.0 87 0.9 202 72 62 16 8.1 Max. 9.4 7.4 Min. 1.9 3.0 10.0 0.3 38 23 52 351 57 12.4 7.58 Mean 2.8 6.3 37 0.7 112 39 3.0 2.54 0.13 S.D. 0.62 2.62 43 0.37 72.7 20.5 22.1 41.6 116 52.9 64.9 52.6 5.3 20.5 1.7 C.V. 15.6 7.7 Max. 3.4 9.5 125 1.4 200 69 60. 52 7.3 Min. 1.8 2.5 13 0.4 25 19 8.8 Units i Heavy metals ppb Ca and Mg ppm -460- jablf A4.15 ^ a^inatJL^^ - ~ Eccli'j.bnurrir Tributaries Fe Mn Ca Mg pH Site CU Pb Zn Cd 327 67 44 10.4 7.49 4.2 29.2 1.01 185 Mean 3.0 22.25 1.50 2.32 0.20 0.61 1.44 33.95 0.75 98. 28 S.D. 53.1 33.2 2.3 22.3 2.7 20.3 34.3 116.3 74.3 C.V. 335 90 46 13.6 7.8 4.0 6.0 96 1.95 7.15 Max. 0.3 55 30 42 7.2 Kin. 2.3 2.5 5.6 331 63.5 14 .7 7. 5 24.3 0.64 124.5 92.5 Mean 2.6 2.8 7.39 2 .55 0.1 7 S.D. 0.73 0.69 24.0 0.20 82.22 112.16 2. 3 0.3 66.0 121.3 11.6 17 .3 C.V. 28.1 24.6 98.8 7. 7 1.05 254 334 78 18 .0 Max. 3.9 4.0 75.0 7. 2 0.4 22 12 54 11 .6 Kin. 1.6 2.0 6.2 347 84 10.1 7.4 93 1.5 114 143 • Mean 2.4 7.7 13.1 1.03 0.2 61.9 0.65 86.7 56.0 S.D. 0.53 3.6 15.6 10.2 2.7 22.1 46.8 66.6 43.3 76.1 39.2 C.V. 295 250 104 11.6 7.6 3.1 14.0 217 2.1 Max. 0.2 46 74 70 8.8 7.1 Min. 1.4 3.5 33 315 230 71 8.7 7.4 Mean 2.9 5.4 26 1.2 80 50.8 69.9 8.9 2.1 0.1 S.D. 0.84 3.8 8.7 0.64 1.4 63.5 30.4 12.5 24.1 C.V. 29.0 70.4 33.5 53.3 7.5 185 345 88 12.0 Max. 4.5 13.6 38 2.4 7.2 0.4 29 140 62 6.0 Min. 1.7 3.0 12 Units t heavy metals t ppb t Ca and Mg » PP"> -461- TaUr A'l.lf £ ur ".a r j Data for Total ExcKaticrc abl < Metal the Pivtr Feel fstx.urnc Site Cu f'b ZT, Cd Fr Mn 35? Mean 4.3 40.7 121 1.9 527 216 S.D. 1.39 20.02 54.7 0.98 149.3 67.8 C.V. 32.3 49.6 51.6 2b.3 31.4 Max. 5.7 65.0 216 3.3 750 305 Hin. 1.8 12.0 51.0 0.5 365 137 318 Moan 11.1 46 124 2, .1 442 144 S.D. 6.37 41.47 55.97 0. ,32 147.4 38.76 C.V. 57.4 90.2 45.1 15. ,2 33.4 26.9 Max. 20 130 205 2. ,3 700 205 Min. 4.7 21.0 62- 1. ,5 265 114 328 Mean * 7 .0 22 .6 98.4 1. ,8 326 128 S.D. 0 .73 8 .38 85.7 0. .83 163 20.8 C.V. 10 .4 37, .1 87.1 46. ,1 50.0 16.3 Max. 8 .0 35, .0 250 3. ,0 545 160 Min. 6 .1 13, .0 46.0 0. ,9 131 109 321 Mean 5 .0 44. ,8 58.5 1. 7 421 107 S.D. 1, .64 27. .7 38.0 0. 75 129.1 40.4 C.V. 32, .8 61. ,8 65.0 44. 1 30.7 37.8 Max.8 7. .0 86. 0 130 2. 7 600 181 Min. 2. .8 19. 0 29.0 0. 8 274 65 336 Mean 4. 6 41 .0 50.2 1.8 420 95 S.D. 1. 28 27 .8 36.4 0.86 115.1 45.8 C.V. 27. 8 67 .8 72.5 47.8 27.4 48.2 Max. 6. 7 80 .0 120 2.9 538 178 Min. 2. 8 12 .0 27.0 1.0 250 58 325 Mean 4 .1 20 53.7 1.1 366 104 S.D. 1 .09 12.3 46.8 0.44 73.0 47.8 C.V. 26 .6 61.5 87.2 40.0 20.0 46.0 Max. 5 .2 44.0 145 1.7 450 195 Min. 2 .6 9.0 21.0 0.7 253 52.0 327 Mean 3.5 13. 6 37.2 1.0 325 82 S.D. 0.61 8. 6 27.0 0.70 93.7 26.2 C.V. 17.4 63. 2 72.6 70.0 28.8 32.0 Max. 4.2 30. 0 88 2.0 425 123 Kin. 2.6 6. 5 14.0 0.0 190.0 50.0 351 Mean 4.1 31 57.5 1.3 498 101 S.D. 1.17 27.7 63.1 0.99 343 63.0 C.V. 28.5 89.4 109.7 76.2 68.9 62.4 Max. 5.7 85 185 3.1 1175 196 Min. 2.4 13 22.0 0.5 215 43 -462- Tablr A4.17 Surr.ii r i bfd Data for Total Exchaj-rraMc _Hntaj rjvff Ecclt sbournc "Tributaries Si te Co Pb Zn Cd Fe Mn 322 208 Mean 4. 2 8, ,7 30.3 0.9 579 S.D. 1. 52 5. ,25 26.32 0.47 178.34 155.03 C.V. 36. 2 11. ,5 86.9 52.2 30.8 74.5 Kax. 7. 1 19. ,0 82 1.7 915 489 67 Kin. 3. 0 5. ,0 8.7 0.4 405 331 168 Kcan 3. 88 7. ,0 36.2 1.2 280.5 200.06 S.D. 1. 82 3. .65 27.52 0.41 256.7 C.V. 46. 9 52. ,1 76.0 34.2 91.5 119.1 Kax. 7. 3 15. ,1 91.0 1.9 830 601 20 Min. 2. 01 5. ,0 10.4 0.7 49 347 Mean 4. ,0 34.7 119 2.4 479 224 S.D. 0. .7 10.7 36.3 1.1 117 85 C.V. 17. .5 30.8 30.5 45.8 24.4 38.0 Kax. 5. ,4 52 175 4.3 635 370 Min. 2. ,7 23.5 62 0.8 337 120 315 Mean 5. ,6 31.4 105 2.2 512 357 S.D. 2. ,2 32.1 131 1.0 115 115.7 C.V. 39. 3 102.2 124.8 45.5 22.5 32.4 Kax. 8. ,5 100 395 3.5 665 603 Min. 2. ,9 7.5 28,2 0.7 314 255 Units i ppb -463- Table A4.18_ Individual Subsample Statistics for Replicate Sediment Analyses Attack Sample 08/78/31 mo3 Cu Mean Min. Max. S.D. C.V. A 520 400 600 72 13.76 B 504 480 520 20 3.89 C 7 20 680 800 51 7.03 D 912 7 20 1040 117 12.83 E 708 660 760 35 4.93 F 1016 920 1120 64 6.27 Pb Mean Min. Max. S.D. C.V. A 18118 17920 18840 361 2.00 B 19264 17920 20600 1198 6.22 C 23496 22360 24960 848 3.61 D 25880 24120 29400 ' 1846 7.13 E 21832 19720 23240 1317 6.03 F 20424 18840 22360 1167 5.72 Zn Mean Min. Max. S.D. C.V. A 20480 19640 21440 814 3.97 B 20232 19640 20840 424 2.10 C 25728 24120 27400 1044 4.06 D 31768 26800 42040 5356 16.86 E 25384 23520 25920 1270 5.00 F 32552 28600 34600 2089 6.42 Cd Mean Min. Max S.D. C.V. A 156 148 168 6.9 4.39 B 158 148 168 6.5 4.10 C 200 176 216 13.4 6.69 D 218 208 232 8.2 3.79 E 197 192 208 5.9 2.99 F 252 232 272 15.6 6.19 Fe(%) Mean Min. Max. S.D. C.V. A 1.95 1.86 2.00 0.05 2.64 B 2.04 2.00 2.08 0.03 1.24 C 1.98 1.88 2.04 0.05 2.75 D 1.92 1.86 2.00 0.07 2.42 E 1.92 1.84 1.98 0.05 2.49 F 1.92 1.84 2.02 0.07 3.64 Mn Mean Min. Max. S.D. C.V. A 3752 3720 3800 30 0.80 B 3624 3520 3760 78 2.16 C 3896 3800 3960 54 1.39 D 3952 3880 4080 78 1.96 E 3976 3840 4080 86 2.17 F 4024 3920 4080 106 2.64 Ca(%) Mean Min. Max. S.D. C.V. A 14.8 14.6 14.8 0.08 0.54 B 14.2 13.2 17.0 1.43 10.08 C 14.8 14.4 15.0 0.20 1.33 D 15.3 14.8 16.6 0.71 4.64 E 15.0 14.8 15.6 0.32 2.14 F 16.2 15.0 17.0 0.90 5.58 Mg Mean Min. Max. S.D. C.V. A 1976 1920 2000 32 1.62 B 2112 2080 2120 16 0.76 C 1928 1880 2000 39 2.03 D 1808 1800 1840 16 0.88 E 1912 1880 1920 16 0.84 F 1784 1760 1840 32 1.79 -464- Table A4.18 (contd.) - 2 Sample 08/78/03 HN03. Attack Cu Mean Min. Max. S.D. C.V. A 45.8 39.6 59.2 72 15.8 B 44.3 40.0 50.0 3.5 7.82 C 45.2 39.2 50.8 4.3 9.4 D 52.3 42.0 68.0 8.6 16.38 E 58.8 50.0 76.0 9.7 16.43 F 49.5 40.0 58.8 6.8 13.49 Pb Mean Min. Max. S.D. C.V. A 1420 1400 1440 18.0 1.26 B 1438 1400 1520 44 3.06 C 1210 1120 1320 64 5.28 D 1830 1600 2000 156 8.56 E 1720 1520 1880 • 121 7.05 F 1430 1400 1480 30 2.07 Zn Mean Min. Max. S.D. C.V. A 1773 1752 1800 17 0.94 B 1780 1704 1900 65 3.67 C 1873 1840 1920 26 1.41 D 1801 1744 1880 45 2.47 E 1799 1720 1860 45 2.52 F 1813 1740 1872 49 2.71 Cd Mean Min. Max. S.D. C.V. A 14.2 14.0 14.4 0.18 1.26 B 16.0 15.6 16.4 0.25 1.58 C 15.5 15.2 16.0 0.30 1.91 D 12.7 12.4 12.8 0.15 1.22 E 12.1 12.0 12.4 0.15 1.28 F 14.1 13.6 14.4 0.30 2.10 Fe(%) Mean Min. Max. S.D. C.V. A 3.25 3.20 3.32 0.05 1.43 B 3.43 3.32 3.56 0.08 2.26 C 3.20 3.12 3.28 0.05 1.58 D 3.16 3.04 3.24 0.07 2.12 E 3.33 3.24 3.40 0.05 1.59 F 3.27 3.20 3.32 0.05 1.42 Mn Mean Min. Max. S.D. C.V. A 1920 1880 2000 44 2.28 B 2130 1960 2280 102 4.81 C 1860 1640 2000 120 6.45 D 1690 1560 2000 163 9.63 E 1930 1800 2160 125 6.47 F 1910 1840 2000 53 2.77 Ca(%) Mean Min. Max. S.D. C.V. A 1.18 1.16 1.20 0.02 1.52 B 1.08 1.04 1.12 0.04 3.31 C 1.28 1.28 1.28 0 0 D 1.16 1.08 1.20 0.04 3.78 E 1.22 1.16 1.32 0.05 4.40 F 1.12 1.08 1.20 0.04 3.91 Mg Mean Min. Max. S.D. C.V. A 4290 4240 4320 30 0.69 B 4170 4000 4280 93 2.22 C 4540 4480 4600 40 0.88 D 4060 4000 4080 31 0.76 E 4120 4000 4240 80 1.94 F 4130 4080 4240 59 1.42 -465- Table A4.18 (contd.) - 2 Sample 08/78/328 HNO3 Attack Max. S.D. C.V. SubsampleMean Min. 0 on A 48.8 48 52 1.6 3. 28 B 48.0 44 52 2.5 5.27 C 42.0 40 44 1.8 4.26 D 42.4 36 52 5.4 12.79 E 43.2 40 48 3.0 6.93 F 36.0 — - 0 0 Pb Mean Min. Max. S.D. C.V. A 7408 7000 7600 228 3.08 B 7536 7 240 7760 169 2.24 C 7592 7120 8280 456 6.01 D 8048 10040 6360 ' 1208 15.02 E 6976 6440 7320 303 4.35 F 6304 5760 6720 415 6.59 Zn Mean Min. Max. S.D. C.V. A 1534 1248 1936 224 14.64 B 1314 1216 1368 67 5.13 C 1223 1068 1456 148 12.08 D 1325 1216 1424 79 5.97 E 1265 1128 1544 147 11.65 F 1169 1068 1276 67 5.72 Cd Mean Min. Max. S.D. C.V. A 24.6 21.6 26.4 1.8 7.30 B 17.0 15.6 18.4 0.9 5.29 C 14.9 12.8 16.8 1.3 8.74 D 17.7 14.8 20.4 1.9 10.84 E 16.5 15.6 18.0 0.9 5.41 F 15.8 14.4 16.8 0.9 5.92 Fe(%) Mean Min. Max. S.D. C.V. A 2.03 1.96 2.10 0.06 3.09 B 2.20 2.06 2.32 0.09 3.92 C 2.08 1.96 2.18 0.07 3.39 D 1.90 1.80 2.08 0.1 5.08 E 1.94 1.84 2.04 0.07 3.41 F 1.80 1.76 1.84 0.03 1.47 Mn. Mean Min. Max. S.D. C.V. A 976 960 1000 19.6 2.01 B 880 800 920 50.6 5.75 C 684 640 720 26.5 3.88 D 704 640 760 40.8 5.79 E 768 760 800 16.0 2.08 F 744 .. 720 760 15.0 2.01 C a (%) Mean Min. Max. S.D. C.V. A 4.10 4.0 4.24 0.1 2.52 B 3.25 3.2 3.32 0.04 1.21 C 3.08 2.92 3.16 0.09 2.85 D 3.15 3.10 3.2 0.03 1.11 E 3.06 3.0 3.16 0.06 2.03 F 3.25 3.2 3.32 0.05 1.54 Mg Mean Min. Max. S.D. C.V. A 1792 1680 1840 64 3.57 B 1648 1600 1720 46 2.83 C 1664 1560 1760 74 4.46 D 1560 1480 1640 56 3.63 E 1552 1480 1640 59 3.79 F 1520 1480 1600 44 2.88 Units 1 ppm except where stated otherwise -466- Table A4.18 (contd.) - 2 Sample 08/78/351 HNO3 Attack Cu Subsample Mean Min. Max. S.D. C.V. A 29 28 32 1.6 5.56 B 30.4 28 32 1.9 6.45 C 26.4 24 28 2.0 7.42 D 30.0 28 32 1.8 5.96 E 29.6 28 32 2.0 6.62 F 30.4 28 36 3.2 10.53 Pb Mean Min. Max. S.D. C.V. A 851 796 916 52 6.15 B 774 732 796 23 2.94 C 871 784 956 61 7.01 D 830 776 916 47 5.71 E 872 828 1004 77 8.88 F 846 788 916 57 6.75 Zn Mean Min. Max. S.D. C.V. A 468 456 480 9.0 1.87 B 461 452 488 14 3.03 C 449 424 488 23 5.12 D 474 460 488 10 2.18 E 446 416 464 17 3.70 F 475 436 512 24 5.09 Cd Mean Min. Max. S.D. C.V. A 3.8 3.2 4.0 0.32 8.33 B 3.8 3.2 4.4 0.48 12.77 C 3.2 2.0 4.4 0.76 23.72 D 4.0 3.2 4.0 0.51 12.65 E 3.6 2.8 4.4 0.67 18.59 F 3.9 3.2 4.8 0.64 16.33 Fe(%) Mean Min. Max. S.D. C.V. A 2.81 2.72 2.92 0.07 2.32 B 2.96 2.88 3.12 0.09 2.96 C 2.84 2.80 2.88 0.03 0.89 D 3.17 3.08 3.24 0.05 1.68 E 2.82 2.80 2.88 0.03 1.13 F 2.94 2.88 3.00 0.05 1.63 Mn Mean Min. Max. S.D. C.V. A 1216 1160 1240 32 2.63 B 1216 1200 1240 19.6 1.61 C 1084 1040 1120 26.5 2.44 D 1304 1240 1400 54.26 4.16 E 1264 1240 1320 32 2.53 F 1292 1240 1340 34.87 2.70 Ca Mean Min. Max. S.D. C.V. A 3108 3080 3140 24 0.77 B 3292 3120 3520 153 4.64 C 2768 2680 2880 78 2.80 D 3200 3080 3320 80 2.50 E 3164 3120 3360 100 3.16 F 3392 3120 3600 155 4.56 Mg Mean Min. Max. S.D. C.V. A 1024 960 1120 60 5.85 B 1048 1000 1120 39 3.74 C 936 920 960 20 2.09 D 1040 1000 1080 25 2.43 E 1024 960 1080 41 3.98 F 1072 1000 1120 47 4.35 -467- APPENDIX 5 -468- Data Listing This Appendix contains the data which have been presented only in summarised form in the text. The units used are as follows: i) Stream sediments, soils and mine waste; ppm except Fe and Ca which are usually expressed as % dry weight. ii) Water analyses; ppb except Ca and Mg which are expressed as ppm. iii) Where no sample/analysis was available this is shown: —, ND signifies concentration below the detection limit. iv) Sampling occasions for Minsterley Brook were 12/77 — 10/78 at two monthly intervals and for the River Ecclesbourne 10/77 — 08/78 also at two monthly intervals. -469- Results for the Digestion of Sartorius Filters Unwashed Filters Sample Cu Pb Zn Cd Fe Mn 096 2.7 ND 16.5 ND 76.3 ND 097 2.2 13.3 98.1 098 1.6 12.1 87.2 099 2.7 14.8 98.1 100 3.2 15.5 79.5 179 4.3 16.8 109.0 Acid Washed Filters Sample Cu Pb Zn Cd Fe Mn 083 2.4 ND 10.1 ND 90.1 ND 085 1.2 8.7 111.3 087 1.2 8.7 79.5 094 0.6 7.4 95.4 Units j ppm dry wt. Heavy Metal Content of Filtered DIW Unacidified through Sartorius Filters Cu Pb Zn Cd Fe Mn SI 0.25 1.0 2.0 0.5 3.0 ND S2 0.20 1.0 2.4 0.2 3.5 0.5 S3 0.15 1.0 2.5 ND 3.0 ND S4 0.30 1.5 2.5 0.1 3.5 0.5 Acidified through Sartorius Filters Cu Pb Zn Cd Fe Mn S5 0.3 0.5 1.40 ND ND ND S6 0.3 0.5 1.35 0.2 4.0 S7 0.4 0.5 1.45 0.4 3.0 S8 0.3 0.5 1.10 0.6 4.0 -470- Unacidified through GFC Filters CU Pb Zn Cd Fe G1 0.45 ND 5.4 0.3 2.5 G2 1.25 0.5 3.1 0.3 • 2.0 G3 0.50 ND 4.5 0.3 7.0 G4 0.35 1.5 4.3 0.3 2.0 Unacidified Unfiltered Cu Pb Zn Cd Fe Mn W1 0.2 ND 0.25 0.5 2.5 ND i W2 ND 1 0.70 ND 2.5 Acidified Unfiltered Cu Pb Zn Cd Fe W3 0.3 ND 0.9 0.4 2.5 W4 0.4 1.5 0.8 0.5 4.5 Units i ppb -471- Data for Bulk Water Samples from the River Ecclesbourne Site 347 Filtrable - Sartorius Filters Cu Pb Zn Cd Fe Mn A5 3.5 6.5 115 1.1 24 89 A6 ?.5 4.8 88 1.4 21 68 B5 2.7 4.0 87 1.3 17 64 B6 2.9 4.0 82 1.8 . 16 62 C5 2.3 3.5 105 1.6 16 93 C6 3.0 3.0 93 1.6 16 78 Filtrable - GFC Filters Cu Pb Zn Cd Fe Mn A9 3.4 7.5 90 1.7 75 68 A10 3.3 7.5 95 1.3 75 70 B9 3.2 6.5 92 1.6 65 69 BIO 2.9 7.0 83 1.5 60 65 C9 3.5 5.5 100 1.7 55 82 CIO 3.1 6.5 98 2.0 70 67 Particulate - Sartorius Filters Wt.Parti- Cu Pb Zn Cd Fe Mn culate A3 5.4 200 114 1.6 990 78 57.8 A4 5.8 190 120 1.5 1100 81 65.0 B3 5.3 170 108 2.6 1000 77 61.4 B4 5.5 180 112 2.5 930 76 61.0 C3 4.8 170 102 2.5 905 70 55.7 C4 6.3 185 110 3.0 1035 69 59.4 Total metals - GFC Filters Cu Pb Zn Cd Fe Mn All 8.0 170 215 2.8 1000 147 B12 8.0 160 220 3.3 1075 169 Cll 8.5 190 235 3.2 1100 152 CI 2 8.2 190 245 -3.2 1115 151 -47 2- Total metals - acid digestion Cu Pb Zn Cd Fe Mn Al 12.5 250 250 5.0 ' 2100 146 A2 14.0 210 255 4.0 2450 162 B1 13.0 170 255 4.5 2400 156 B2 11.5 200 235 4.5 2250 144 CI 15.5 200 240 4.5 2300 150 C2 12.3 200 238 4.3 2250 144 Units s metals ppb s weight of particulate ppm -473- Analyses of Mine Dump Material from Gravels Mine Sample Cu Pb Zn Cd Fe Mn Ca Mg D/l/A 316 3. 84 2. 56 180 0. 64 6800 30 .0 308 D/l/B 312 3. 80 2. 64 192 0. 60 6800 32 .0 280 D/2/A 472 3. 68 1. 69 132 0. 76 6800 30 .0 300 D/2/B 516 4. 12 3. 08 228 0. 80 6800 30 .0 292 D/3/A 532 3. 28 0. 73 60 0. 57 •7200 30 .0 260 D/3/B 476 2. 64 0. 85 68 0. 56 7200 32 .0 268 D/4/A 400 2. 24 2. 24 188 0. 80 6800 28 .0 372 D/4/B 460 1. 40 4. 00 332 0. 96 6000 28 .0 520 D/5/A 416 1. 84 3. 60 284 0. 88 6800 - - D/5/B 664 1. 76 4. 40 372 1. 00 6000 - - D/6/A 616 2. 12 2. 4 212 0. 84 5600 24 .0 3680 D/6/B 300 1. 20 1. 16 136 0. 70 6400 - - D/l/A 392 1. 96 1. 43 132 0. 72 6400 28 .0 328 D/7/B 544 3. 04 1. 10 164 0. 72 6000 28 .0 320 D/8/A 380 1. 88 1. 28 124 0. 56 7600 32 .0 228 D/8/B 296 1. 84 0. 94 100 0. 52 7600 - - D/9/A 172 2. 64 1. 76 152 0. 76 6640 30 .0 1680 D/10/A 450 3. 27 1. 01 92 0. 63 6880 30 .0 292 D/10/B 536 3. 68 0. 95 84 0. 64 6800 - - D/ll/A 336 4. 64 2. 68 200 0. 60 7200 32 .0 260 D/ll/B 312 4. 12 2. 84 204 0. 56 6800 - - D/12/A 468 3. 51 0. 90 83 0. 58 7120 32 .0 268 D/12/B 424 3. 48 0. 88 80 0. 56 6800 - - Note, Units : Zn and Pb are expressed as % O -474- Analyses of Ore Minerals Chalcopyri.te Cu(%) Pb Zn Cd . Feb) Mn Co 37 420 6100 40 31 ND 3700 37 590 6100 40 31 ND 3700 36 270 6000 38 33 ND 3200 Sphalerite Cu Pb Zn(%) Cd Fe (%) Mn Co 1210 490 64 4400 1.95 ND 160 1140 270 60 4200 2.00 ND 170 2040 900 67 4100 2.00 ND 170 Galena Cu Pb(%) Zn Cd Fe(ppm) Mn Co 4 6.8 103 5 200 ND ND 4 7.1 4 5 120 3 7.2 6 3 200 o -475- Heavy Metals in-Sewage Effluent - Wirksworth Water Reclamation Works Sewage Effluent Filtrable Ipp^ Cfp^ Cu Pb Zn Cd Fe Mn Ca Mg pH 10/77 20.4 13.8 98 1.6 113 24 60 9.6 6.95 12/77 10.0 7.5 108 1.3 93 23 76 9.0 7.30 04/78 9.0 5.0 73 0.7 45 90 114 13.6 7.15 08/78 14 5.5 54 1.3 50 18 92 11.0 7.20 Total Exchangeable Cu Pb Zn Cd Fe Mn 10/77 34 29 155 3.6 180 34 12/77 16 23 120 1.7 185 35 04/78 24.5 32.5 139.5 2.1 210 97 08/78 38 25 136 3.1 245 48 ko Minsterley Brook Site 33 31 30 28 107 10 126 134 Distance (km) 0 1.20 2.60 4.20 6.85 9.35 11.55 13.95 17.40 22.20 Site 352 318 328 321 336 325 327 351 Distance (km) 0 0.40 1.60 3.57 5.50 7.10 10.10 12.50 w H- ft (D 0 H- W ri- 01 3n (D M -477- Sf-asor.al Data - Hinstcrlev brook Nitric Attack Site Cu Pb Zn Cd Mn C»[c/c) Mg 39 .2 224 .0 304 .0 2.4 3.80 920 .0 0.22 4160 .0 27 .2 268 .0 392 .0 2.8 3.60 760 .0 0.56 3400 .0 24 .0 288 .0 300 .0 2.4 3.40 800 .0 0.20 3920 .0 3 29 28, .8 312, .0 384 .0 3.2 3.50 1000 .0 0.24 4000, .0 28. ,0 400. .0 584, .0 4.0 4.96 3160, .0 0.20 2532, .0 1200. ,0 4360. ,0 28000. ,0 208.0 .0.80 5600. ,0 30.00 480. ,0 2480. 0 32000. 0 46400. 0 336.0 0.88 5000. 0 30.00 1400. ,0 516. 0 34400. 0 9200. 0 73.6 0.47 6400. 0 31.60 440. 0 33 256. 0 29200. 0 7000. 0 56.0 0.80 6800. 0 30.40 680. 0 864. 0 68000. 0 24000. 0 180.0 1.12 7200. 0 25.00 480. 0 1300. 0 16000. 0 44000. 0 384.0 0.76 6800. 0 29.00 3000. 0 1600 .0 26800.0 37200 .0 332.0 3.64 4400 .0 21 .00 1400.0 1600 .0 28000.0 45600 .0 360.0 3.72 3880 .0 19 .60 3440.0 744 .0 24000.0 25600 .0 212.0 3.76 4000 .0 17 .60 3760.0 31 588, .0 20000.0 19600 .0 188.0 3.84 4320 .0 18 .00 3880.0 730, .0 21502.0 26024 .0 197.0 3.96 3873, .0 15, .00 3920.0 636. ,0 24400.0 51200. .0 144.0 2.80 3800, .0 11. .00 2000.0 720. ,0 26800.0 20800. .0 176.0 2.48 3600. ,0 35. ,40 2440.0 504. ,0 20000.0 18800. ,0 140.0 2.32 3080. 0 33. ,60 2480.0 560. 0 20000.0 16000. 0 124.0 2.36 3120. 0 32. 80 2680.0 30 292. 0 13200.0 15800. 0 120.0 2.36 3400. 0 32. 80 2760.0 312. 0 10800.0 12800. 0 304.0 2.48 3360. 0 31. 00 3720.0 368. 0 44000.0 24400. 0 344.0 2.80 3800. 0 33. 00 2000.0 360.0 8000.0 11200 .0 88.0 2.88 2640.0 8 .40 3200.0 384.0 12000.0 11120 .0 84.0 2.72 2240.0 6 .40 3240.0 240.0 6000.0 6560 .0 48.0 2.92 2160.0 5 .08 3800.0 28 404.0 18000.0 9800 .0 81.0 2.80 2040.0 0, .56 3400.0 184.0 6000.0 6760 .0 58.0 2.96 2160.0 5. .04 2120.0 212.0 5600.0 7960, .0 88.0 3.24 2160.0 5. ,04 2400.0 408.0 7640.0 6600. ,0 42.4 2.76 1400.0 3. 60 3440.0 307 380.0 4040.0 5000. 0 35.2 2.68 1280.0 3. 24 3080.0 152.0 5600.0 4240. 0 38.0 2.72 .1280.0 2. 68 2120.0 162.0 4400.O 5880. 0 56.0 2.88 3440.0 4. 00 2332.0 V_) \y\J<\o ' tr -478- Seasonal Data - Kinr.terley Brook Nitric Attack (contd.) Site Cu Pb Zn Cd Mn cfc) Mg 160.0 3680.0 5200.0 37 .6 2.64 1470.0 3.60 3520.0 109.0 3440.0 4400.0 31 .0 2.80 1400.0 3.72 3800.0 10 128.0 3480.0 3640.0 22 .0 2.76 1240.0 2.88 3720.0 144.0 3280.0 4800.0 40 .8 2.88 1440.0 3.68 3720.0 104.0 2560.0 4520.0 41 .2 —2.84 1200.0 2.92 2920.0 160.0 4000.0 4040.0 40 .0 2.92 1600.0 2.56 2468.0 82.0 2320.0 2400.0 16, ,0 2.52 1040.0 1.60 3400.0 99.0 1880.0 1840.0 12, .0 2.92 1160.0 1.70 4200.0 9 74.0 1720.0 1520.0 10, .4 .2.80 1120.0 1.32 4320.0 108.0 2720.0 3640.0 28. ,8 2.84 1360.0 2.44 3880.0 120.0 2600.0 2880.0 26. ,0 2.88 1680.0 2.08 2480.0 125.0 2000.0 2160.0 18. 0 3.80 1760.0 2.06 2532.0 48.0 1520.0 1880.0 8. 0 2.80 1080.0 1.40 3880.0 85.0 1600.0 1680.0 10. 0 2.80 1040.0 1.48 3920.0 3 72.0 1440.0 1440.0 8. 4 2.80 1280.0 1.20 4200.0 51.0 1200.0 1660.0 11. 2 2.84 1400.0 1.20 3800.0 48.0 1508.0 1807.0 14. 1 3.27 1907.0 1.17 4218.0 44.0 1240.0 1392.0 12. 0 3.16 1400.0 1.72 2320.0 38.0 840.0 688.0 5.2 2.12 760.0 0.48 3320.0 16.0 800.0 820.0 4.0 2.20 800.0 0.60 3360.0 126 20.0 688.0 808.0 5.6 2.28 1000.0 0.60 3800.0 19.0 568.0 752.0 5.2 2.28 920.0 0.48 3560.0 34.0 600.0 760.0 5.6 2.32 1360.0 0.58 2280.0 18.0 760.0 808.0 2.4 2.16 920.0 0.60 3440.0 30.0 680.0 672.0 4.0 2.40 1040.0 0.20 4000.0 134 17.0 504.0 800.0 4.8 2.16 960.0 0.48 3480.0 20.0 472.0 704.0 6.0 2.24 960.0 0.68 3400.0 28.0 400.0 680.0 4.4 2.28 1360.0 0.76 2120.0 24.0 520.0 806.0 7.0 2.36 1960.0 0.88 3068.0 VJ V\A /V) *** -479- Seasonal Data - Hinr.terley BrooV. 0.5M HCl leach Site Cu Pb Zn Cd Fe(ppm) Mn Ca(ppm) Mg 7 .0 146 .0 80 .0 1.2 2180.0 360 .0 2400.0 400.0 8 .4 184 .0 72 .0 1.2 2760.0 360 .0 1800.0 360.0 129 ------10 .2 234 .0 100 .0 1.8 3400.0 620 .0 2400.0 380.0 10, .0 190. .0 154, .0 1.6 5000.0 1160. .0 3400.0 360.0 18. ,6 6600. 0 3700. ,0 23.2 920.0 4000. 0 196000.0 160.0 J J 30. 0 21560. 0 2744. 0 28.0 . 2436.0 5880. 0 207000.0 196.0 34. 0 21250. 0 4000. 0 37.5 2600.0 4800. 0 195000.0 200.0 26. 0 4500. 0 7425. 0 62.5 1325.0 4150. 0 210000.0 150.0 ______20.4 16800. 0 2600. 0 25. 2 1000, .0 4000. 0 196000, ,0 200.0 33.6 16320. 0 3960. 0 35. 5 2448. .0 4080. 0 220800. ,0 216.0 37.2 15320. 0 4219. 0 36. 5 2454. ,0 3263. 0 139000. 0 266.0 35.4 15000. 0 4080. 0 40. 8 2640. 0 3160. 0 132000. 0 260.0 36. ,4 16000.0 3660. ,0 29. ,4 3360. ,0 3480. ,0 148000.0 340.0 30 27. 6 16000.0 3000. 0 22. 8 2380. 0 2980. 0 134000.0 280.0 30. 0 10800.0 4000. 0 32. 4 3000. 0 3000. 0 122000.0 380.0 32. 8 •10000.0 3720. 0 31. 0 2880. 0 2520. 0 10200.0 360.0 36. 0 10000.0 5340. 0 43. 6 3480. 0 2780. 0 88000.0 420.0 21.6 8800.0 2400.0 17.3 2600.0 2200.0 92000.0 360.0 28 26.4 11000.0 3080.0 29.2 3280.0 1740.0 54000.0 420.0 23.6 4600.0 2740.0 28.0 3000.0 1560.0 48000.0 340.0 16.0 3360.0 3080.0 35.0 2800.0 1420.0 46000.0 380.0 21.6 5600.0 1840.0 10.0 1920.0 1020.0 44000.0 7.2 1240.0 790.0 6.2 2480.0 580.0 56000.0 580.0 107 17.4 3740.0 2520.0 14.6 2900.0 1000.0 30400.0 380.0 27.6 4200.0 2160.0 20.0 2420.0 880.0 26600.0 280.0 29.8 3620.0 2180.0 20.0 2440.0 900.0 24000.0 300.0 -480- Seasonal Data -Hin sterley Brook - 0.5H HCl leach (contd) Si te Cu" Pb Zn Cd Fe(ppm) Hn Ca(ppm) Mg 14 .0 340 .0 3840.0 30.4 2440.0 1020.0 40000.0 440.0 10 ------18 .4 3120 .0 2580.0 26.0 3120.0 1320.0 34200.0 500.0 35 .2 3 960 .0 2940.0 25.6 2620.0 840.0 24000.0 880.0 17 .4 3040 .0 2920.0 33.0 2480.0 1040.0 32000.0 600.0 10 .6 2200 .0 830.0 5.6 2600.0 840.0 23200.0 300.0 11 .0 3660, .0 740.0 5.8 2800.0 660.0 16400.0 320.0 Q 14, .4 2540. .0 3200.0 9.0 4000.0 1100.0 23600.0 360.0 15. .6 3740. ,0 3300.0 33.6 3580.0 1100.0 18200.0 340.0 14. ,0 3660. ,0 808.0 7.'6 4120.0 820.0 13600.0 320.0 12. 3 3300. 0 696.0 5.4 2880.0 760.0 15400.0 380.0 10. 6 3380. 0 680.0 4.6 2680.0 660.0 15000.0 320.0 3 15. 0 3 3 60. 0 3040.0 8.6 3800.0 1160.0 12000.0 400.0 19. 2 3387. 0 3063.0 10.4 4261.0 1182.0 10700.0 474.0 18. 0 3000. 0 630.0 7.2 2860.0 820.0 9400.0 320.0 8.0 680.0 390.0 3.0 2980.0 520.0 5200.0 560.0 6.4 680.0 332.0 2.6 1960.0 400.0 6600.0 240.0 126 7.4 540.0 422.0 4.0 2560.0 640.0 4800.0 280.0 6.0 400.0 408.0 3.2 2260.0 640.0 4200.0 240.0 7.2 560.0 348.0 2.4 2880.0 520.0 5400.0 380.0 8.0 600.0 372.0 3.0 2800.0 640.0 5600.0 300.0 134 7.6 420.0 290.0 2.6 2280.0 520.0 5000.0 280.0 11.2 340.0 404.0 3.0 2700.0 760.0 5000.0 320.0 8.4 320.0 348.0 3.6 2300.0 920.0 4600.0 280.0 V_) WA. Xo fr -481 - Seasonal Data - Minr.trrley Brook FiltrabJe Metals Site Cu Pb Zn Cd Fe Mn Ca Mg 2.3 3.5 34.0 1.1 298.0 60.0 26.0 6.6 4.0 7.0 31.0 4.4 320.0 120.0 34.0 129 4.1 7.0 29.0 0.9 360.0 67.0 30.0 6.4 3.2 5.0 9.6 0.2 245.0 30.0 28.0 6.8 3.1 2.5 27.0 0.5 300.0 43.0 32.0 7.6 1.5 3.8 8.0 0.4 340.0 28.0 34.0 7.6 3.0 18.3 847.0 13.5 266.0 50.0 34.0 6.4 4.4 10.0 260.0 6.2 140.0 83.0 25.0 6.5 33 4.0 25.0 415.0 7.0 273.0 32.0 38.0 7.6 6.2 22.0 1640.0 28.0 2*20.0 70.0 46.0 7.2 3.5 18.0 1850.0 25.0 210.0 49.0 56.0 7.8 2.5 17.5 1355.0 23.0 148.0 115.0 52.0 8.4 3.7 65.0 1394.0 14.4 133.0 55.0 40.0 6.0 4.4 32.0 695.0 8.3 64.0 88.0 32.0 5.4 31 4.1 69.0 1143.0 9.9 178.0 59.0 45.0 6.4 3.1 68.0 1359.0 13.0 53.0 70.0 50.0 6.2 3.6 54.0 1930.0 17.0 103.0 41.0 57.0 7.0 2.5 52.0 2069.0 22.0 34.0 85.0 57.0 6.3 3.6 43.3 1174.0 1 2.4 1 21.0 50.0 38.0 6.2 5.2 85.0 890.0 11.0 210.0 80.0 48.0 7.5 30 4.0 55.0 1150.0 10.0 165.0 55.0 44.0 7.0 3.3 33.0 1100.0 13.0 60.0 65.0 48.0 6.6 3.3 25.0 1775.0 16.0 95.0 44.0 . 54.0 7.0 3.0 20.0 1860.0 17.6 91.0 85.0 52.0 7 .2 2.8 22.0 709.0 7.5 103.0 31.0 40.0 7.0 5.2 54.0 420.0 6.2 340.0 54.0 44.0 5.8 28 5.1 38.0 360.0 4.0 460.0 31.0 36.0 6.2 3.5 22.0 670.0 7.8 85.0 23.0 46.0 7.6 2.8 16.0 820.0 9.1 105.0 32.0 54.0 8.2 2.5 15.0 1020.0 9.8 65.0 32.0 54.0 8.6 2.2 16.0 799.0 5.7 78.0 20.0 36.0 5.6 4.0 33.0 470.0 8.2 300.0 37.0 50.0 5.8 107 5.5 40.0 510.0 3.8 413.0 37.0 40.0 6.4 2.2 14.0 760.0 5.9 55.0 20.0 46.0 6.2 2.2 13.0 825.0 5.8 80.0 15.0 50.0 6.0 2.0 8.8 1175.0 7.0 30.0 16.0 5B.0 7.6 -482- Seasonal Data - Kinstf-rley BrooK - Filtrable Metals (contd.) Site Cu Pb Zn Cd Fe Mn Ca Mg 1.9 e.e 727.0 5.1 36 .0 21 .0 44 .0 6.4 3.9 13.0 547.0 4.0 40, .0 37 .0 66, .0 6.7 10 7.0 54.0 650.0 5.3 59, .0 50, .0 50, .0 7.0 2.9 14.0 401.0 2.7 110, ,0 56, ,0 50. ,0 7.8 2.5 8.0 550.0 2.9 30. ,0 35. ,0 56. ,0 8.8 * 3.0 14.0 700.0 4.6 21. 0 12. ,0 56. 0 8.8 1.8 5, .0 199.0 1.8 58.0 80 .0 76.0 10.6 4.2 8, .0 150.0 1.9 120.0 . 71 .0 100.0 10.5 5.4 35, .0 400.0 3.0 420.0 56, .0 66.0 9.4 2.2 12. ,0 166.0 1.0 65.0 65, .0 74.0 11.2 2.2 8. ,0 245.0 1.1 70.0 40. .0 78.0 12.0 2.0 8. 8 341.0 1.7 29.0 32. ,0 82.0 12.0 2.0 2.5 174.0 - 48.0 75.0 78.0 11.2 3.2 7.0 130.0 2.3 105.0 45.0 96.0 — 3 2.1 3.0 133.0 1.0 30.0 33.0 86.0 12.0 2.4 8.0 146.0 0.7 29.0 44.0 74.0 11.2 2.6 8.5 165.0 0.9 50.0 35.0 78.0 12.0 3.0 8.2 202.0 1.7 35.0 30.0 80.0 13.0 1.8 4.6 122.0 1.1 78.0 ' 67.0 72.0 10.0 4.0 12.0 121.0 1.7 280.0 62.0 88.0 10.0 126 2.1 3.0 105.0 0.9 60.0 22.0 84.0 11.0 2.4 4.0 89.0 0.5 24.0 15.0 74.0 11.0 2.6 7.0 127.0 0.8 60.0 26.0 74.0 12.0 2.0 10.0 151.0 0.9 30.0 13.0 82.0 12.0 1.8 6.0 84.0 0.6 78.0 63.0 72.0 11.2 3.6 11.8 98.0 1.1 218.0 56.0 96.0 11.8 134 2.1 2.5 63.0 1.1 50.0 22.0 80.0 12.4 2.3 4.0 62.0 0.4 55.0 17.0 84.0 11.0 2.7 6.5 103.0 0.8 50.0 25.0 90.0 14.0 2.5 8.8 65.0 2.2 20.0 50.0 96.0 14.8 o \AA ho w CcV Streamvater pH Occasion Site 12/77 02/78 04/78 06/78 08/78 10/78 129 7.2 6.8 6.9 6.9 7.7 7.4 33 7.3 6.9 7.1 7.1 7.6 7.6 31 7.6 6.9 7.5 7.5 7.8 7.7 30 7.6 7.0 7.6 7.6 8.0 7.8 28 7.5 7.0 7.6 7.6 7.8 7.7 107 7.6 7.2 7.6 7.6 7.9 7.8 10 7.7 7.9 7.8 7.8 7.9 7.9 9 7.5 7.5 7.8 7.8 8.2 8.1 3 7.5 7.6 8.2 8.2 8.3 7.9 126 7.7 7.6 8.4 8.4 8.7 8.3 134 7.8 7.7 8.4 8.4 8.4 8.2 -403- Srasonal Data - Hinst«T)ey BropV Total Exchanoeable Metal« Site Cu Pb 2n Cd Fe Mn 2.4 6.0 55.0 1.6 348.0 75.0 5.3 21.0 50.0 5.5 - 250.0 129 5.B 37.0 58.0 1.7 1360.0 307.0 4.3 15.0 19.0 0.3 810.0 110.0 3.5 8.0 34.0 1.4 675.0 84.0 2.0 11.0 16.0 0.7 990.0 83.0 3.3 30.0 894.0 12.4 273.0 55.0 6.0 29.0 335.0 7.6 600.0 166.0 33 5.8 155.0 665.0 10.6 .1023.0 212.0 7.3 48.0 1738.0 30.1 550.0 84.0 4.2 43.0 1951.0 27.2 485.0 82.0 2.7 46.0 1447.0 25.2 523.0 126.0 4.8 96.0 2500.0 15.9 173.0 60.0 8.8 392.0 1015.0 12.8 554.0 145.0 31 6.9 264.0 1493.0 17.7 491.0 112.0 4.3 124.0 1455.0 16.5 127.0 75.0 4.4 89.0 2003.0 17.9 158.0 44.0 3.3 83.0 2146.0 23.4 79.0 89.0 4.7 85.0 1520.0 12.4 138.0 52.0 12.6 585.0 1400.0 18.0 940.0 168.0 30 4.1 64.0 1165.0 15.2 120.0 70.0 4.2 45.0 1817.0 17.1 140.0 47.0 3.4 31.0 1899.0 18.5 121.0 87.0 3.2 46.0 794.0 7.9 168.0 35.0 10.4 404.0 820.0 11.7 1250.0 159.0 28 11.5 328.0 865.0 14.0 1060.0 121.0 4.2 39.0 736.0 8.9 140.0 30.0 3.5 28.0 849.0 9.8 160.0 39.0 2.8 23.0 1050.0 11.3 98.0 36.0 2.4 29.0 849.0 6.7 123.0 26.0 9.0 423.0 1070.0 14.2 1230.0 157.0 107 10.5 330.0 1170.0 10.8 1693.0 227.0 2.7 24.0 804.0 6.6 300.0 23.0 2.9 25.0 841.0 7.2 118.0 23.0 2.2 12.0 1194.0 7.9 44.0 18.0 -484- Seasonal Data - Kinsterlcy BrooK - Total Exchangeable Metals {contd. Site Cu Pb Zn Cd Fe Mn 2.1 22.0 789.0 5.2 73.0 25.0 6.4 79.0 590.O 8.8 570.0 97.0 10 11.4 314.0 1220.0 11.1 1550.0 200.0 3.4 24.0 486.0 4.7 200.0 65.0 2.9 16.0 605.0 3.9 144.0 45.0 3.7 27.0 783.0 6.1 126.0 42.0 2.3 11.0 229.0 1.5 353.0 100.0 6.4 66.0 272.0 2.6 780.0 161.0 9 10.0 265.0 930.0 8.6 1510.0 246.0 2.9 23.0 206.0 2.1 275.0 110.0 2.7 25.0 306.O 1.9 250.0 67.0 2.6 15.0 366.0 2.1 229.0 64.0 2.1 13.0 199.0 2.0 323.0 85.0 5.7 65.0 260.0 3.4 895.0 140.0 2.6 10.0 183.O 9.0 220.0 136.0 3 3.2 23.0 196.0 2.2 254.0 104.0 3.1 19.0 197.0 1.5 200.0 63.0 3.6 16.0 228.0 2.2 235.0 68.0 2.1 13.0 145 .0 1.4 303.0 75.0 6.0 52.0 203, • O 2.5 810.0 138.0 3.0 10.0 150. .0 1.5 229.0 72.0 3.0 13.0 119. O 1.5 209.0 68.0 3.0 17.0 151. 0 1.6 225.0 69.0 2.4 15.0 162. 0 1.1 150.0 23.0 2.5 14.0 131.0 1.5 373.0 90.0 4.0 19.0 115.0 1.3 336.0 76.0 2.6 8.0 98.0 2.5 245.0 57.0 2.8 17.0 83.0 0.9 215.0 70.0 3.1 14.0 118.0 1.0 185.0 61.0 2.9 13.0 72.0 2.4 115.0 35.0 -485- Seasonal Data - Kinnterlev Brook Particulates Site Cu Pb Zn Cd Fe Mn 129 23.7 4ie.o 397.0 11.1 13928.0 3343.0 48.5 441.0 401.0 4.4 24900.0 3524.0 37.0 463.0 648.0 83.0 34722.0 3796.0 38.0 492.0 598.0 23.0 49242.0 4167.0 33 38.0 2434.0 4682.0 67.0 14045.0 3371.0 204.0 4814.0 18148.0 389.0 61100.0 2592.0 57.0 2049.0 8279.0 180.0 22541.0 2705.0 47.0 6512.0 21395.0 581.0 87209.0 2558.0 31 131.0 8716.0 16055.0 349.0 14220.0 2523.0 182.0 8530.0 14469.0 530.0 11800.0 803.0 421.0 18421.0 38421.0 1632.0 28947.0 1316.0 216.0 8378.0 20811.0 514.0 12162.0 1081.0 30 68.0 5190.0 8478.0 97.0 20588.0 3114.0 186.0 7209.0 15000.0 511.0 13900.0 1046.0 321.0 6964.0 15000.0 393.0 16071.0 1071.0 400.0 10500.0 38500.0 900.0 30000.0 1500.0 28 36.0 1652.0 2876.0 57.0 3417.0 513.0 127.0 3181.0 8273.0 200.0 10000.0 1273.0 189.0 3243.0 7B38.0 189.0 14865.0 1622.0 83.0 2222.0 8333.0 417.0 9167.0 1111.0 07 31.0 1786.0 4064.0 43.0 7882.0 1170.0 119.0 2381.0 10476.0 167.0 10600.0 714.0 104.0 1716.0 6866.0 209.0 5672.0 1194.0 80.0 1200.0 7600.0 360.0 5600.0 600.0 Sr«»«w>r,el Data - Kin-.terlcy BrooK - Particulates (rontd.) Site Cu Pb Zn " Cd Fe Hn 34.0 2028.0 4446.0 45.0 7488.0 1170.0 10 54.0 1087.0 9239.0 217.0 9800.0 978.0 56.0 1042.0 7639.0 139.0 15972.0 1389.0 88.0 1625.0 10312.0 188.0 13125.0 3688.0 35.0 1753.0 4040.0 43.0 8308.0 1448.0 9 58.0 875.0 3292.0 92.0 17500.0 3750.0 39.0 1289.0 4766.0 63.0 14063.0 2109.0 82.0 822.0 3425.0 55.0 27397.0 4384.0 67.0 867.0 6667.0 107.0 25333.0 6667.0 3 63.0 1142.0 3937.0 118.0 17700.0 4724.0 56.0 1167.0 3556.0 67.0 16666.0 3111.0 77.0 962.0 3333.0 64.0 25641.0 4808.0 99.0 714.0 4945.0 66.0 18132.0 5495.0 26 63.0 885.0 3125.0 104.0 19300.0 5469.0 41.0 1020.0 2449.0 82.0 16837.0 4388.0 89.0 1111.0 2400.0 44.0 26667.0 2222.0 45.0 693.0 3465.0 139.0 19307.0 3465.0 134 47.0 1206.0 1934.0 47.0 15100.0 4953.0 52.0 909.0 1948.0 26.0 17532.0 4675.0 63.0 625.0 1141.0 31.0 14844.0 4453.0 0\AA fc Tf -487- Seasonal D.f - Fiv' Eccl t-sbourr.e Nitric Attack Mn Ca Ma Site Cu Pb Zn Cd Fe 780 .0 1.02 3080, .0 64 .0 4160.0 2000 .0 22. 8 2.18 800 .0 10.40 3240, .0 60 .0 4520.0 2160 .0 26. 4 2.16 640 .0 9.60 3200, .0 352 63 .0 5600.0 2200 .0 27. 2 2.12 .0 10.40 37 20,. 0 74 .0 4800.0 1640 .0 27. 2 2.17 560 840 .0 9.60 3440, .0 104 .0 3080.0 1880 .0 27. 6 2.26 2.12 1160 .0 11.00 3468, .0 94 .0 - 1800 .0 24. 0 2.56 780.0 91 .0 19200.0 1760 .0 32. 0 2.40 8.00 2920.0 86 .0 6880.0 1680 .0 24. 8 880.0 2.32 680.0 8.12 2960.0 318 56 .0 6320.0 1840 .0 23. 2 2.44 840.0 5.76 2400.0 72 .0 23600.0 2560 .0 30. 0 2.40 7.20 2840.0 82 .0 52000.0 2000 .0 25. 5 680.0 2.04 640.0 6.40 2936.0 56 .0 16000.0 2440 .0 35. 2 1360 .0 19. 2 2.00 1000.0 40 .0 10000.0 3.00 1720.0 2040 .0 23. 2 2.44 1120.0 52 .0 15200.0 3.08 1720.0 12000.0 1600 .0 20. 0 2.08 800.0 328 42 .0 920.0 3.16 1840.0 12400.0 1440 .0 17. 6 2.12 44 .0 960.0 3.24 2000.0 6000.0 1520 .0 20. 0 3.08 54 .0 793.0 3.32 1623.0 43 .0 7311.0 1305 .0 17. 8 1.99 680.0 27 .0 9600.0 1080 .0 12. 4 2.06 1.80 520.0 1.28 1040.0 22 .0 5120.0 864 .0 10. 0 1.52 500.0 1.36 1040.0 321 23 .0 6560.0 1016 .0 8. 8 1.48 400.0 1.40 1120.0 .0 4880.0 736 .0 8. 4 19 760.0 1.04 1080.0 26 .0 5800.0 824 .0 11. 2 1.92 640.0 1.40 1070.0 22 .0 6400.0 844 .0 11. 6 1.92 7.2 1.88 920.0 0.80 760.0 20.0 3600.0 680.0 760.0 3360.0 432.0 4.0 1.60 560.0 0.60 14.0 0.64 920.0 5360.0 680.0 7.6 1.68 600.0 336 17.0 0.56 800.0 2040.0 428.0 4.4 1.44 600.0 17.0 840.0 0.64 960.0 19.0 3680.0 480.0 5.2 1.72 1.92 560.0 0.67 832.0 20.0 2460.0 556.0 5.2 1240.0 608.0 6.0 2.80 960.0 0.52 30.0 1040.0 0.50 1120.0 24.0 1360.0 512.0 5.2 2.48 920.0 640.0 0.44 1000.0 325 22.0 1800.0 616.0 6.4 2.16 560.0 7.6 2.64 1160.0 0.40 1240.0 30.0 1200.0 1240.0 1840.0 656.0 7.2 2.50 880.0 0.60 21.0 0.59 1264.0 24.0 1680.0 464.0 4.8 2.72 1320.0 1480.0 0.32 1280.0 27.0 1000.0 536.0 4.0 2.88 720.0 0.34 840.0 20.0 640.0 332.0 2.4 2.00 640.0 0.24 800.0 327 20.0 620.0 320.0 2.0 2.00 368.0 3.6 2.08 800.0 0.28 960.0 22.0 616.0 0.32 960.0 22.0 720.0 432.0 5.2 2.52 1120.0 1400.0 0.30 800.0 28.0 920.0 480.0 5.6 2.08 0.33 880.0 23.0 760.0 448.0 3.2 2.60 1080.0 840.0 0.30 960.0 24.0 920.0 416.0 4.8 2.90 760.0 0.27 880.0 351 23.0 800.0 408.0 4.0 2.44 488.0 5.6 2.80 1120.0 0.32 1000.0 28.0 880.0 0.32 1000.0 720.0 424.0 4.0 2.56 1080.0 22.0 1229.0 0.31 1024.0 29.0 841.0 462.0 3.7 2.92 V3 VVA Xo Gov a. ^jl y Seasonal Data - River Ecclesboume 0.5M HC1 leach Site Cu Pb Zn Cd Fe(ppm) Mn Ca(ppm) Mg Occasion 70.0 2920.0 1020.0 21.0 6000.0 94000.0 352 640.0 2140.0 06/78 144.0 5600.0 1100.0 21.0 5200.0 720.0 82000.0 1840.0 08/78 48.0 20000.0 3360.0 318 46.0 6800.0 540.0 32000.0 780.0 06/78 28.0 13200.0 1500.0 24.0 3320.0 380.0 48000.0 1100.0 08/78 328 31.0 5000.0 920.0 15.0 6800.0 680.0 28200.0 760.0 06/78 25.0 5906.0 676.0 12.0 4706.0 629.0 27920.0 678.0 08/78 15.0 5400.0 442.0 8.0 321 4000.0 560.0 8600.0 320.0 06/78 13.0 4660.0 408.0 6.8 3480.0 440.0 9800.0 300.0 08/78 11.0 1840.0 304.0 4.6 5400.0 06/78 336 4400.0 640.0 260.0 10.0 1640.0 242.0 3.6 3560.0 560.0 4600.0 260.0 08/78 18.0 1640.0 348.0 5.0 06/78 325 8000.0 1280.0 4800.0 820.0 13.0 1120.0 170.0 2.6 4400.0 600.0 2400.0 260.0 08/78 3.4 327 12.0 700.0 182.0 4600.0 800.0 3000.0 320.0 06/78 14.0 620.0 160.0 2.8 5000.0 760.0 2920.0 320.0 08/78 11.0 620.0 3.4 06/78 351 186.0 4400.0 700.0 2400.0 340.0 14.0 654.0 181.0 3.0 4776.0 788.0 2904.0 330.0 08/78 -489- Srasonal Data - River Eccleshourne Filtrable Metals Ca Mg Site Cu ' Pb Zn Cd Fe Mn 94, .0 1.6 363, .0 263.0 100 .0 11.2 4.6 35. .0 10.0 2.5 190. .0 0.8 70. ,0 154.0 90 .0 .0 8.2 352 2.3 8. ,5 95. .0 2.2 50. .0 115.0 84 .0 9.6 3.1 8. ,5 53. .0 1.0 170, .0 75.0 84 .0 11.0 1.4 4. .0 36, .0 0.2 80. .0 260.0 76 .0 10. 2 2.9 10. .5 85. .0 0.8 150, .0 85.0 92 66 .0 7.6 10.0 38, .0 92. .0 1.9 200, .0 87.0 8.0 7.4 13. .0 250, .0 3.0 131. ,0 160.0 70 .0 68 .0 8.6 318 2.7 2, .5 84, .0 1.6 118. .0 93.0 4.4 2, .5 41. .0 0.8 123, .0 100.0 88 .0 10.9 11.3 7.9 5. .4 45, .0 0.6 87. ,0 56.0 69 .0 10.6 5.3 4, .8 32, .0 0.8 84. .0 . 48.0 89 .0 3 3 5.0 138.0 1.4 58.0 82.0 64.0 8.0 3 4 4.0 61.0 1.3 43.0 80.0 62.0 8.8 328 4 7 7.5 33.0 0.8 100.0 46.0 76.0 11.4 V.l 5.5 37.0 0.6 40.0 32.0 60.0 12.0 5.0 10.0 28.0 0.8 105.0 48.0 78.0 11-2 5.8 18.0 45.0 1.0 165.0 37.0 64.0 11.3 2.7 6.0 122.0 1.5 90.0 70.0 56.0 8.0 1.8 3.5 34.0 1.0 24.0 75.0 52.0 9.0 321 3.0 6.0 18.0 0.5 95.0 32.0 60.0 9.8 4 5 5.5 25.0 2.0 55.0 80.0 58.0 13.2 2 [g 8.5 15.0 0.5 65.0 47.0 68.0 11.2 6.4 39.0 28.0 2.9 230.0 41.0 64.0 12.0 2.7 6.0 116.0 1.3 72.0 42.0 54.0 8.0 1.8 4.5 27.0 0.9 39.0 65.0 46.0 8.6 336 3.7 5.1 18.0 0.7 131.0 56.0 54.0 11.6 3 o 5.5 19-0 0.6 45.0 50.0 58.0 13.2 2]g 3.0 13.0 0.5 60.0 23.0 60.0 11.4 4 6 11.0 32.0 0.9 195.0 30.0 60.0 14.0 4 0 4.6 96.0 1.1 93.0 48.0 52.0 8.0 325 1.9 3.0 23.0 0.8 31.0 75.0 46.0 8.4 3 4 3.5 15.0 0.6 105.0 32.0 86.0 11.6 2*7 4.5 14.0 0.5 60.0 55.0 50.0 12.2 3'.! 6.0 10.0 0.5 115.0 27.0 50.0 10.0 3 5 8.0 28.0 0.9 195.0 32.0 60.0 16.0 3*5 7.0 87.0 0.7 202.0 72.0 56.0 9.4 1*9 4.0 24.0 0.8 38.0 60.0 52.0 10.6 327 3*.5 3.0 15.0 0.8 90.0 23.0 60.0 12.6 2 5 3.5 14.0 0.3 60.0 50.0 56.0 14.8 2.*9 5.0 10.0 0.5 1 50.0 29.0 62.0 1 2.6 3 4 9.0 26.0 0.5 200.0 29.0 60.0 15.6 3*4 5.0 125.0 1.4 113.0 69.0 56.0 8.8 lie 2.5 26.0 0.6 25.0 60.0 52.0 10.4 351 2.4 9.5 13.0 0.9 185.0 19.0 56.0 12.8 2 7 5.5 18.0 0.4 110.0 29.0 56.0 14.6 2*9 6.0 16.0 0.6 36.0 26.0 60.0 12.0 \ Ov ^ -490- Seasonal Data - River Ecclesbourne Total Exchangeable Metals Site Cu Pb Zn Cd Fe Mn 5.5 65.0 125.0 1.7 750.0 290.0 5.7 50.0 216.0 3.3 385.0 207.0 352 4.3 56.0 129.0 2.7 365.0 137.0 4.4 25.0 91.0 2.0 460.0 195.0 1.8 12.0 51.0 0.5 590.0 305.0 4.2 - 36.0 114.0 1.5 610.0 163.0 18.0 • 130.0 205.0 2.3 700.0 205.0 6.2 33.0 180.0 2.3 265.0 120.0 318 4.7 29.0 111.0 2.3 346.0 114.0 9.8 27.0 89.0 1.9 440.0 133.0 20.0 36.0 97.0 1.5 478.0 180.0 8.0 21.0 62.0 2.1 428.0 114.0 7.4 13.0 250.0 3.0 131.0 160.0 6.7 26.0 81.0 2.1 253.0 111.0 328 6.1 18.0 57.0 1.6 270.0 136.0 8.0 21.0 58.0 0.9 435.0 127.0 6.7 35.0 46.0 1.2 545.0 109.0 6.4 69.0 70.0 1.5 385.0 65.0 5.8 86.0 130.0 2.7 600.0 181.0 321 2.8 26.0 50.0 1.4 274.0 94.0 3.9 19.0 37.0 1.1 315.0 112.0 7.0 22.0 35.0 2.4 400.0 108.0 4.1 47.0 29.0 0.8 550.0 80.0 6.7 80.0 60.0 2.9 435.0 58.0 5.0 70.0 120.0 2.8 530.0 178.0 336 2.8 22.0 38.0 1.2 250.0 86.0 4.6 12.0 29.0 1.0 319.0 114.0 4.0 24.0 27.0 2.0 450.0 74.0 4.5 38.0 27.0 1.1 538.0 58.0 5.0 18.0 38.0 1.6 365.0 52.0 5.0 44.0 60.0 1.7 428.0 195.0 325 2.6 15.0 33.0 1.0 253.0 93.0 5.2 9.0 25.0 0.8 315.0 97.0 3.3 19.0 21.0 0.7 450.0 95.0 3.6 15.0 145.0 0.8 385.0 90.0 3.5 6.5 44.0 0.9 190.0 4.1 30.0 88.0 2.0 419.0 123.0 327 2.6 14.0 33.0 1.1 253.0 77.0 4.2 7.0 24.0 1.5 305.0 78.0 3.1 11.0 20.0 0.6 360.0 82.0 3.4 13.0 14.0 0.0 425.0 50.0 3.8 19.0 34.0 0.7 375.0 60.0 5.7 36.0 185.0 3.1 485.0 196.0 351 2.4 13.0 32.0 0.8 215.0 74.0 5.1 85.0 48.0 1.7 1175.0 164.0 3.9 15.0 24.0 0.5 385.0 68.0 3.6 18.0 22.0 0.7 351.0 43.0 0 ^A X/) - -491- Seasonal Data - River Ecclesbourne Particulate Site Cu Pb Zn Cd Fe Mn 118.0 2794.0 2000.0 29.4 18529.0 1265.0 352 176.0 2162.0 5068.0 122.0 39189.0 16216.0 82.0 1633.0 3020.0 61.0 104082.0 9148.0 120.0 2315.0 2685.0 65.0 42593.0 7222.0 154.0 2024.0 2045.0 52.0 19345.0 1616.0 318 429.0 1960.0 3786.0 87.0 25158.0 9762.0 534.0 1372.0 2323.0 39.0 17534.0 5561.0 84.0, 512.0 904.0 39.0 10361.0 2018.0 234.0 1560.0 1418.0 58.0 14894.0 2199.0 328 187.0 1400.0 3133.0 100,0 22667.0 12000.0 400.0 2727.0 3727.0 55.0 71818.0 17273.0 168.0 2475.0 1782.0 40.0 43564.0 6040.0 321 109.0 1667.0 2436.0 77.0 28205.0 10256.0 291.0 2909.0 1764.0 73.0 62727.0 5091.0 176.0 5135.0 1892.0 41.0 65541.0 4459.0 122.0 2012.0 1378.0 37.0 25700.0 2561.0 336 164.0 1226.0 2057.0 57.0 35472.0 10943.0 105.0 2288.0 869.0 39.0 31046.0 2288.0 325 91.0 1493.0 1312.0 26.0 28571.0 2403.0 375.0 1042.0 2125.0 42.0 43750.0 13542.0 162.0 4117.0 1971.0 59.0 114706.0 11764.0 102.0 1837.0 918.0 61.0 55102.0 3673.0 88.0 1284.0 1189.0 34.0 29054.0 2297.0 327 194.0 1111.0 2583.0 194.0 59722.0 15278.0 86.0 1379.0 724.0 - 47414.0 3621.0 61.0 1220.0 756.0 24.0 22561.0 1646.0 351 55.0 1518.0 709.0 15.0 20040.0 2935.0 181.0 1809.0 1223.0 21.0 58511.0 7979.0 121.0 2069.0 966.0 17.0 54310.0 2931.0 Units t ppm dry weight -492- Streamvater pH Occasion Site 10/77 12/77 02/78 04/78 06/78 08/78 352 7.4 7.5 7.3 7.7 7.7 7.6 318 7.2 7.4 7.4 7.4 7.4 7.4 328 - 7.5 7.4 7.9 7.5 7.5 321 7.3 7.5 7.4 7.8 7.6 7.8 336 7.3 7.5 7.3 7.8 7.6 7.7 325 7.5 7.4 7.3 8.2 7.7 7.6 327 7.5 7.5 7.4 8.1 7.7 7.7 351 7.6 7.6 7.3 7.6 7.7 7.7 -493- Seasonallv Sampled Tributary Sites - Minsterley Brook Site 029 Sediments - HN03 Attack (ff~\ Cu Pb Zn Cd Fe % Mn Ca 7. Mg 12/77 40.8 1440 1880 10.4 3.72 1120 0.60 4520 02/78 N.S. N.S. 04/78 46.4 1920 1880 12.4 3.16 1240 0.44 4720 06/78 22.4 1680 2000 14.4 3.36 1280 0.48 4240 08/78 20.0 1640 1572 14.8 3.28 1360 1.58 2680 10/78 24.0- 2800 1920 18.0 3.56 1840 0.26 2932 Filtra ble Metals *5H 12/77 1.4 11.0 259 1.9 133 40 38 8.2 7.7 02/78 3.6 27.0 113 1.1 190 40 42 12.0 6.9 04/78 4.5 47.0 184 1.3 500 .43 32 8.5 7.7 06/78 1.6 11.5 65 0.7 155 13 38 8.4 7.7 08/78 1.4 11.5 40 0.6 175 18 46 8.6 7.9 10/78 2.0 10.0 42 1.4 130 12 46 9.0 7.4 Total Exchangeable Metal s Cft\>) 12/77 1.9 25 334 2.4 500 56 02/78 5.6 187 241 2.5 1190 150 04/78 7.7 367 494 5.8 2220 363 06/78 2.0 30.5 91 1.0 305 32 08/78 1.6 26.5 57.5 0.9 355 39 10/78 2.3 20.0 49.2 1.7 235 24.5 Site 02 Sediments - HNO- Attack Cff**) Cu Pb Zn Cd Fe % Mn Ca % Mg 12/77 13.2 200 196 N.D. 1.84 520; 0.20 3200 02/78 14.8 236 176 0.8 2.00 520 0.21 3560 04/78 11.6 252 196 1.2 1.88 480 0.20 3600 06/78 15.2 280 172 2.0 2.00 520 0.21 3520 08/78 16.0 320 184 2.0 2.32 720 0.20 3280 10/78 12.0 200 252 1.6 3.04 640 0.25 2332 Filtrable Metals CmA^ pH 12/11 1.7 3.0 7.7 1.4 100 15 28 6.2 7.5 02/78 3.3 2.5 4.0 0.6 41 N.S. 28 5.8 7.6 04/78 2.0 2.9 5.1 0.3 72 6.6 46.5 7.6 06/78 2.3 2.9 4.8 0.3 81 7.3 41.0 7.4 08/78 2.1 3.0 7.5 0.2 105 7.5 44.0 7.8 8.5 10/78 1.2 2.9 7.0 0.4 60 9.3 33.0 9.6 7.9 Total Exchangeable Metals C fY^>) 12/77 4.2 10.5 27.7 1.6 425 50 02/78 4.2 7.5 10.0 1.0 296 26 04/78 2.2 5.4 6.8 0.3 158 16.6 06/78 2.7 5.4 6.8 0.3 167 17.9 08/78 2.4 6.1 9.8 0.4 245 20.3 10/78 2.4 5.4 8.0 0.6 101 19.7 -494- Site 105 Sediments - HNO~ Attack (y^ Cu Pb Zn Cd Fe Mn Ca % Mg 12/11 No sample 02/78 No sample 04/78 22.4 304 244 2.4 2.92 880 0.40 5400 06/78 19.2 488 280 2.4 3.20 1240 0.44 4600 08/78 36.0 600 328 2.4 3.16 2360 2.00 2920 10/78 23.0 72.0 488 3.6 3.88 2520 0.43 3000 Filtrable Metals C W pH 12/77 1.5 , 2.5 13.5 0.5 83 107 84 12.2 7.4 02/78 3.4 5.0 18.0 0.6 430 110 102 12.1 7.3 04/78 3.7 9.0 36 0.5 348 100 86 12.4 7.7 06/78 1.8 2.5 8.3 0.3 115 . 70 84 13.2 7.7 08/78 1.9 6.0 12.5 0.4 95 39 90 14.2 8.3 10/78 2.0 6.3 14.0 0.7 250 75 92 14.0 7.6 Total Exchangeable Metals Lift) 12/77 3.7 7.5 15.5 1.4 583 232 02/78 5.2 18.0 32.0 0.8 1090 207 04/78 4.3 14.0 40.7 1.7 478 126 06/78 3.5 11.5 34.8 0.8 460 130 08/78 2.2 8.5 14.3 0.5 220 54 10/78 2.4 10.8 18.6 0.8 ' 590 160 -495- Snailbeach Level Filtrable Metals V.?? fv* W Cu Pb Zn Cd Fe Mn Ca Mg pH 7.3 12/77 0.7 91 674 5.2 6.5 21 64 6.6 02/78 1.2 100 730 5.8 20.0 26 80 13.2 7.1 04/78 1.1 120 558 5.4 33.0 34 66 7.0 7.2 06/78 1.2 106 720 5.6 10 12 60 6.8 7.2 08/78 1.1 80 685 5.8 17 41 64 7.6 7.5 10/78 1.0 75 702 5.8 18 45 64 7.4 7.1 12/77 Total Exchangeable Metals 02/78 1.7 123 740 5.9 40 35 04/78 1.4 127 560 6.7 38 34 06/78 1.5 112 721 5.6 15 12 08/78 1.1 86 684 5.8 17 41 10/78 1.1 80 704 5.9 22 46 Site 132 Sediments - HNO~ Attack ( ?f«*i) Cu Pb Zn Cd Fe 7o Mn Ca % Mg 12/77 13.2 48 156 0.8 2.16 1440 0.32 4000 02/78 04/78 16.8 72 164 1.2 2.32 1960 0.36 4680 06/78 19.6 124 204 1.2 2.40 1360 0.44 4400 08/78 16.0 120 160 3.2 2.48 1760 0.43 2680 10/78 27.0 60 184 1.6 2.88 2520 0.35 3068 >le Metals ^V) m 12/77 1.7 2.5 11.5 0.2 150 105 86 15.8 7.7 02/78 3.8 5.0 13.0 0.5 270 120 116 33.2 7.7 04/78 1.7 2.5 4.8 0.3 135 42 114 18.8 8.0 06/78 2.3 3.0 20.0 0.4 75 25 - - 8.0 08/78 _ _ — — 132 23 8.0 10/78 2.5 3.8 7.0 0.7 110 44 138 22.4 7.9 Total Exchangeable Metals ( ffV) 12/77 4.3 5.0 25.8 0.6 1050 280 02/78 5.4 10.0 22.5 0.7 850 240 04/78 2.4 5.0 8.9 0.8 465 112 06/78 2.8 5.5 22.0 0.4 285 67 08/78 2.6 6.3 8.0 0.8 185 62 -496- Seasonally Sampled Tributary Sites - River Ecclesbourne HN0 Attack v ff v*; Stream Sediments - 3 347 Cu Pb Zn Cd Fe Mn Ca^ Mg 10/77 81 4160 2200 30 2.2 1160 14 3080 12/77 94 3616 2560 34.4 1.4 800 14 3280 02/78 86 3640 1680 24.8 1.92 800 12.0 3200 04/78 66 4480 1760 26.0 1.92 560 12.0 3280 06/78 68 3600 1840 27.2 1.88 320 12.0 3360 08/78 72 3600 1900 30.0 2.08 680 11.0 3200 315 10/77 68 538 512 10. 8 5. 48 3280 - - 12/77 76 1240 716 14. 4 4. 56 2400 2. 2 1520 02/78 68 1200 920 14. 4 4. 72 2640 4. 0 1920 04/78 62 800 548 11. 6 4. 88 2200 0. 88 1360 06/78 35. 2 1280 628 10. 4 - - 3. 24 — 08/78 76 1280 916 16. 0 5. 72 2560 3. 00 1268 >le Metals 347 Cu Pb Zn Cd Fe Mn Ca Mg 10/77 28 14 60 1.7 295 165 104 11.6 12/77 2.3 5.0 217 2.0 55 126 72 8.8 02/78 2.5 8.0 122 2.1 52 100 70 8.8 04/78 3.1 10.5 78 1.6 143 74 82 10.0 06/78 1.4 5.0 33 0.2 90 250 78 10.8 08/78 2.3 3.5 50 1.1 46 140 100 10.6 315 Cu Pb Zn Cd Fe Mn Ca Mg 10/77 3.0 13.6 38 1.1 185 165 88 12.0 12/77 4.5 6.0 22.7 2.4 75 140 62 6.0 02/78 2.6 3.0 35 1.6 29 240 64 6.2 04/78 2.8 3.5 23 0.8 88 205 68 9.2 06/78 1.7 3.0 22 0.4 50 345 76 10.0 08/78 2.6 3.0 12 1.0 50 285 66 9.0 Total Exchangeable Metals 347 Cu Pb Zn Cd Fe Mn pH 10/77 3.8 31 95 1.6 615 255 7.4 12/77 4.4 52 175 4.3 359 162 7.45 02/78 4.0 46 149 2.6 337 120 7.1 14.6 04/78 3.9 24 113 2.5 415 160 7.45 06/78 2.7 31 62 0.8 635 276 7.3 08/78 5.4! 23.5 119 2.8 512 370 315 Cu Pb Zn Cd Fe Mn pH 10/77 3.95 100 395 3.5 540 343 7.3 12/77 8 37 92 3.1 665 300 7.45 02/78 8.5 17 52 2.4 314 255 7.2 04/78 3.7 11.5 34.5 1.2 433 280 7.40 06/78 2.9 7.5 28.2 0.2 510 360 7.5 08/78 6.4 L5.5 32.0 2.5 610 603 7.4 -497- 322 Cu Pb Zn Cd Fe Mn Ca Mg Sediment - HN03 Attack V f f**) % % 10/77 38. 4 340 272 4. 0 4.16 1440 0.40 1400 12/77 31. 2 288 264 3. 2 3.80 1080 0.22 1080 02/78 40. 8 420 240 4. 0 4.40 1080 0.20 1360 04/78 33. 2 304 456 6. 0 3.20 1160 0.56 2800 06/78 36. 8 332 296 4. 4 4.00 1280 0.32 2080 08/78 46. 0 400 244 4. 4 5.12 2040 1.12 1268 Filtrable Metals I U'H Cw^ PH 10/77 3.0 5.0 22.5 1.95 250 67 46 13.6" 7.4 12/77 4.0 5.0 96 1.90 164 90 44 7.2 7.45 — 02/78 — - - - _ — 7.15 04/78 2.3 2.5 15 0.4 120 30 46 9.4 7.8 06/78 2.4 2.5 5.8 0.3 55 .90 42 12.4 7.65 08/78 3.1 6.0 6.7 0.5 335 60 44 9.2 7.5 Total Exchangeable Metals (.ffb) 10/77 3.4 5.0 23 0.5 530 67 12/77 4.5 8.0 82 1.7 463 260 04/78 3.0 6.0 21.5 0.7 405 110 06/78 3.2 5.5 8.7 0.4 580 113 08/78 7.1 19.0 16.4 1.1 915 489 331 Cu Pb Zn Cd Fe Vo Mn Ca Vo Mg Sediment Iw^-) 10/77 26.0 56 87 1.6 2.00 400 — 12/11 11.2 56 76 1.6 1.04 268 0.12 960 02/18 12.0 56.0 64 1.6 1.12 260 0.09 1000 04/78 12.8 68 80 1.6 1.00 324 0.12 1040 06/78 20.4 56 80 2.4 1.72 440 0.16 1400 08/78 28 160 156 4.0 1.96 520 0.96 1132 y> Filtrable (tn pH 10/77 2.4 2.0 22.0 0.7 180 105 60 18 7.2 12/11 2.8 3.5 75.0 1.05 97 33 78 11.6 7.5 02/78 1.6 2.5 8.5 0.6 22 12 54 11.6 7.3 04/78 2.0 2.5 6.2 0.4 34 20 60 14.3 7.7 06/78 3.9 2.5 27 0.5 254 334 64 17.6 7.6 08/78 2.8 4.0 7.0 0.6 160 51 65 15.3 7.5 Total ( 10/77 2.8 5.5 45 1.1 305 155 12/77 3.4 r 6.0 91 1.5 167 58 02/18 2.01 5.3 12 0.8 158 20 04/78 2.6 5.0 10.4 0.7 174 35 06/78 5.2 5.0 37 1.0 49 601 08/78 7.3 15.1 21.7 1.9 830 140 -498 - Replicate Water Analyses - Minsterlev Brook Filtrable Metals - Site 02 110/78 Cu 02/78 06/78 08/78 10/78 Mn 02/78 06/78 08/78 1 9 1) 0.8 2.2 2.1 1.0 1) 24 7.5 7.5 2) 0.8 2.3 2.2 1.0 2) 23 7.5 8.5 9 10 3) 1.0 2.3 2.6 1.3 3) 27 7.0 8.0 9 4) 1.0 2.4 2.1 1.3 4) ' 30 7.5 8.0 Pb Ca 1) 5.0 3.0 3.0 6.3 1) 42 44 66 2) 5.0 2.5 3.5 4.4 2) _ 40 44 62 44 66 3) 5.0 2.5 2.5 6.5 3) _ 42 42 64 4) 5.0 3.5 3.0 6.0 4) - 40 Zn Mg 9.6 1) 6.1 3.5 7.5 28.5 1) . _ 7.4 7.4 2) 5.4 3.8 7.7 27.5 2) — 7.4 7.8 9.6 9.2 3) 6.3 3.7 6.6 25.5 3) _ 7.4 • 8.0 10.0 4) 6.8 3.6 7.7 26.0 4) - 7.4 8.0 Cd 1) 0.2 0.3 0.2 0.6 2) 0.2 0.3 0.4 0.5 3) 0.2 0.3 0.1 0.7 4) 0.3 0.2 0.4 0.8 Fe 1) 260 75 105 65 2) 220 80 125 60 3) 230 85 115 55 4) 230 85 125 60 Filtrable Metals Site 31 Cu 02/78 06/78 08/78 10/78 Mn 02/78 06/78 08/78 10/78 1) 4.6 3.0 3.7 2.5 1) 90 70 38 85 2) 4.5 2.8 3.4 2.5 2) 89 50 37 90 85 3) 4.2 3.1 3.6 2.5 3) 90 70 44 4) 4.2 3.3 3.7 2.5 4) 84 65 46 80 Pb Ca 1) 30 65 51 53 1) 50 46 60 2) 31 62 52 50 2) 48 48 58 3) 32 72 55 53 3) 50 47 56 4) 33 74 58 50 4) 50 49 54 Zn Mg 1) 680 1380 1950 2055 1) 6.0 7.2 6.4 2) 700 1280 1860 2070 2) 6.0 6.8 6.4 3) 700 1370 1950 2095 3) 6.2 7.2 6.0 4) 700 1405 1960 2055 4) 6.0 6.6 6.4 Cd 1) 8.0 13 16.5 22.0 2) 8.0 12.5 16.5 24.0 ?r 3) 8.6 13 16.5 19.0 4) 8.5 13.5 17.5 21.0 C Total Exchangea ble Metals - Site 31 10/78 Cu 02/78 06/78 08/78 10/78 Mn 02/78 06/78 08/78 89 1) 9.0 4.1 4.4 3.0 1) 151 74.5 40.0 93.5 2) 8.9 4.0 4.2 3.2 2) 145 74.5 39.5 89.5 4.2 4.3 3.5 3) 143 - 46.5 3) 8.2 84.0 4) 8.7 4.6 4.5 3.4 4) 146 - 49.0 Pb 1) 390 125 83 83 2) 380 118 90 83 3) 372 123 87 82 4) 381 134 96 81 Zn 1) 1000 1471 2020 2130 2) 1040 1380 1940 2148 3) 997 1456 2015 2173 4) 1012 1510 2037 2133 Cd 1) 12.6 16.3 19.5 23.9 2) 12.8 16.0 19.8 25.8 3) 12.6 16.2 19.4 20.9 4) 12.7 17.5 20.8 22.8 Fe 1) 520 120 160 79 2) 580 110 165 75 3) 550 135 155 82 4) - 135 150 79 -500- Replicate Water Analyses - River Ecclesbourne Filtrable Metals - Site 318 Cu 02/78 04/78 06/78 08/78 Mn 02/78 04/78 06/78 p8/78 45 1) 2.8 4.4 8.1 5.0 1) 100 20 60 2) 2.6 4.5 8.1 5.2 2) 90 14 55 47 50 3) 2.7 4.4 8.1 5.5 3) 90 22 55 4) 2.7 4.3 7.0 5.7 4) 90 10 50 50 Pb 1) 2.5 2.5 5.5 4.5 2) 2.5 2.5 5.5 4.0 —• 3) 2.5 2.5 5.5 5.5 4) 2.5 •2.5 5.0 5.0 Zn 1) 84 44 46 31 2) 82 40 45 31 3) 84 41 47 32 4) 85 39 41 33 Cd 1) 1.8 0.6 0..6 0.8 2) 1.5 0.7 0.6 0.8 3) 1.5 1.1 0.6 0.8 4) 1.8 0.9 0.6 0.7 Fe 1) 12.0 13.0 100 80 2) 10.5 12.5 80 80 3) 12.5 9.5 85 90 4) 12.0 11.5 80 85 Filtrable Metals - Site 331 Cu 02/78 04/78 06/78 08/78 Mn 02/78 04/78 06/78 08/78 1) 1.7 2.1 3.3 2.6 1) 13 2.0 450 50 2) 2.1 2.0 3.3 2.5 2) 12 2.0 460 50 3) 1.5 2.1 4.6 3.0 3) 11 2.0 445 52 4) 1.3 1.8 4.1 3.0 4) 12 2.0 480 51 Pb 1) 2.5 2.5 2.5 5.5 2) 2.5 2.5 2.5 3.5 2.5 4.0 3) 2.5 2.5 \J ^ Ajo 4) 2.5 2.5 2.5 3.0 Zn Cc\ a 1) 9.3 6.3 28.5 7.0 2) 8.4 6.1 27.0 6.2 3) 8.4 6.1 26.0 7.4 4) 7.9 6.1 23.0 7.3 Cd 1) 0.6 0.4 0.5 0.6 2) 0.5 0.3 0.4 0.5 3) 0.8 0.5 0.4 0.7 4) 0.5 0.4 0.4 0.7 Fe 1) 22 34 280 140 2) 28 38 285 145 3) 21 35 225 180 4) 19 28 195 175 -501- Total Exchangeable Metals - Site 318 Cu 02/78 04/78 06/78 08/78 Mn 02/78 04/78 06/78 08/7 8 1) 4.5 9.5 20.2 7.9 1) 117 205 175 112 2) 5.0 10.4 21.4 8.0 2) 114 240 195 116 113 3) 4.7 10.2 20.0 8.2 3) 112 180 170 118 4) 4.7 9.6 17.2 8.3 4) 112 205 175 Pb — 1) 25.5 27.5 38.5 20.5 2) 33.5 29.5 35.5 22.0 3) 27.5 20.0 37.0 21.5 4) 29.5 27.5 33.0 23.0 Zn 1) 105 88 97 39 2) 115 94 101 64 * 3) 110 74 97 59 4) 113 84 91 64 Cd 1) 2.3 1.4 1.5 2.7 2) 2.0 1.8 1.5 2.2 3) 2.2 1.7 1.5 1.8 4) 2.8 2.4 1.5 1.5 Fe 1) 237 293 480 410 2) 291 363 550 450 3) 263 245 485 415 4) 267 332 383 435 Total Exchangeable Metals - Site 331 Cu 02/78 04/78 06/78 08/78 Mn 02/78 04/78 06/78 08/78 1) 2.0 2.7 5.4 4.1 1) 20.0 14.5 745 85 2) 2.6 2.8 4.8 4.2 2) 22.0 21.0 660 85 92 3) 1.9 2.6 5.4 4.6 3) 18.5 16.0 730 94 4) 1.6 2.4 5.0 4.9 4) 21.5 19.0 795 Pb 1) 5.0 5.0 5.0 11.5 2) 5.5 5.0 5.0 10.5 3) 5.0 5.0 5.0 11.5 \AA X? y Vi 4) 5.5 5.0 5.0 11.0 Zn 1) 12.5 10.1 34.9 13.3 2) 12.5 11.1 34.9 14.1 3) 11.6 9.7 35.3 14.9 4) 11.7 10.4 37.5 16.2 Cd 1) 0.8 0.6 0.8 1.2 2) 0.7 1.0 0.8 1.2 3) 1.0 0.8 1.1 1.5 4) 0.6 0.6 1.1 1.2 Fe 1) 147 169 515 560 2) 183 208 575 655 3) 146 150 530 700 4) 159 168 540 765 -502- Analyses of Replicate Subsamples of Stream Sediments - HNOo Attack Sample 08/78/328 Sample Cu A B C D E F 1 48 • 44 40 52 40 36 2 48 48 44 44 44 36 3 48 48 40 36 44 36 4 52 52 44 40 40 36 5 48 48 42 40 48 36 Pb A B C D E F 1 7600 7240 7120 10040 6440 5840 2 7520 7600 8280 6360 7160 6720 3 7000 7520 7440 7400 7080 6640 4 7320 7560 7160 8280 7320 5760 5 7600 7760 7960 8160 6880 6560 Zn A B C D E F 1 1936 1368 1068 1424 1188 1068 2 1484 1216 1336 1248 1544 1156 3 1248 1368 1128 1368 1188 1188 4 1456 1368 1128 1368 1128 1276 5 1544 1248 1456 1216 1276 1156 Cd A B C D E F 1 2.6 16.8 14.4 18.4 16.8 15.2 2 25.6 16.8 15.2 18.4 18.0 14.4 3 21.6 17.2 12.8 16.4 15.6 16.8 4 23.6 18.4 15.2 20.4 15.6 16.8 5 26.4 15.6 16.8 14.8 16.4 15.6 -503- Sample 08/78/328 (contd.) Sample Fe A B C D E F 1 2.10 2+16 1.96 2.08 1.92 1.80 2 1.96 # 2.06 2.18 1.80 1.98 1.84 3 1.96 2.24 2.08 1.88 2.04 1.82 4 2.04 2.20 2.10 1.92 . 1.94 1.80 5 2.10 2.32 2.08 1.84 1.84 1.76 Mn A B C D E F 1 1000 840 640 760 760 760 2 960 800 680 640 760 720 3 960 920 680 720 800 740 4 960 920 720 720 760 760 5 1000 920 700 680 760 740 Ca A B C D E F 1 4.2 3. 2 3.08 3.2 3.00 3.24 2 4.0 3. 32 3.16 3.12 3.0 3.20 3 4.0 3. 24 2.92 3.10 3.16 3.20 4 4.04 3. 24 3.16 3.16 3.04 3.30 5 4.24 3. 24 3.10 3.16 3.10 3.32 Mg A B C D E F 1 1840 1680 1600 1640 1480 1520 2 1760 1600 1720 1480 1600 1520 3 1680 1600 1560 1520 1640 1480 4 1840 1640 1760 1600 1520 1480 5 1840 1720 1680 1560 1520 1600 0 V\A /Q Cc^ -t F-l Y,0 -504- Sample 08/78/351 Sample Cu A B C D E F 1 28 32 28 32 32 32 -2 32 32 24 28 28 28 3 28 . 28 24 28 28 28 4 28 28 28 32 28 28 5 28 32 28 30 . 32 36 Pb A B C D E F 1 796 732 916 800 912 912 2 828 788 956 828 1004 828 3 912 768 872 916 828 916 4 916 784 784 828 828 788 5 084 796 828 776 788 788 Zn A B C D E F 1 464 452 440 460 452 480 2 464 452 488 476 456 472 3 480 460 432 488 444 472 4 476 452 424 464 416 436 5 456 488 460 480 464 512 Cd A B C D E F 1 4.0 4.0 3.2 4.0 3.2 3.2 2 4.0 3.2 3*2 4.0 3.2 3.2 3 4.0 4.0 2.0 3.2 2.8 4.4 4 3.2 3.2 3.2 4.8 4.4 4.0 5 4.0 4.4 4.4 4.0 4.4 4.8 -505- Sample 08/78/328 (contd.) Fe A B C D E F 1 2.72 2.88 2.84 3.08 2.88 3.0 2 2.80 2.96 2.84 3.16 2.80 2.92 3 2.92 2.88 2.80 3.20 2.80-- 2.92 4 2.IB, 2.96 2.88 3.16 2.80 2.88 5 2.82 3.12 2.84 3.24 2.84 3.00 Ca(ppm) A B C D E F 1 3120 3400 2880 3080 3120 3600 2 3120 3520 2800 3320 3120 3440 3 3140 3280 2680 3200 3360 3400 4 3080 3140 2800 3240 3080 3120 5 3080 3120 2680 3160 3140 3400 m A B C D E F i 1040 1000 920 1000 1080 1080 2 1120 1120 960 1040 1040 1120 3 1040 1040 920 1040 1000 1040 4 960 1040 960 1080 960 1000 5 960 1040 920 1040 1040 1120 Mn A B C D E F 1 1200 1200 1080 1240 1240 1280 2 1240 1240 1120 1400 1240 1280 3 1240 1200 1100 1280 1320 1320 4 1240 1200 1080 1320 1240 1240 5 1160 1240 1040 1280 1280 1340 jj5 y nA\ -506- Sample 08/78/31 Sample Cu A B C D E F 1 400 520 680 840 720 1020 2 600 480 680 - 1000 660 1020 3 560 % 520 760 720 680 1000 4 560 520 680 960 720 920 5 480 480 800 1040 760 1120 Pb A B C D E F 1 17948 17920 24960 24120 23240 18840 2 17920 19280 23240 29400 21480 20600 3 17920 17920 23240 25000 19720 19720 4 17960 20600 22360 25000 23240 22360 5 18840 20600 23680 25880 21480 20600 Zn A B C D E F 1 19640 19920 27400 42040 27400 33400 2 21440 19640 24120 29200 25040 28600 3 19640 20840 25600 29200 23520 34600 4 20240 20520 25600 26800 25040 32480 5 21440 20240 25920 31600 25920 33680 Cd A B C D E F. 1 148 160 280 220 196 248 2 152 148 176 208 196 232 3 160 160 200 232 192 272 4 156 156 200 212 192 240 5 168 168 216 216 208 268 -507- Sample 08/78/328 (contd.) Fe A B C D E F 1 1.86 2.04 2.00 1.88 1.96 1.84 2 2.0 2.00 1.88 2.00 1.92 2.02 -3 1.96 2.04 2.00 1.86 1.84 1.92 4 1.94, 2.04 1.96 1.86 1.92 1.96 5 2.0 2.08 2.04 2.00 1.98 1.84 Mn A B C D E F 1 3720 3760 3880 4000 4000 4000 2 3720 3520 3960 3880 3920 3920 3 3760 3640 3920 3920 3840 4200 4 3800 3600 3800 3880 4040 3920 5 3760 3600 3920 4080 4080 4080 Ca A B C D E F 1 14.8 17.0 15.0 16.6 15.6 17.0 2 14.8 14.0 14.8 15.6 14.8 15.0 3 14.8 13.2 14.8 14.8 14.8 17.0 4 14.8 13.6 14.8 14.8 15.2 5 14.6 13.2 14.4 14.8 16.8 Mg A B C D E F 1 2000 2120 1920 1800 1880 1760 2 2000 2120 1880 1840 1920 1840 3 1920 2120 1920 1800 1920 1760 4 1960 2080 1920 1800 1920 1800 5 2000 2120 2000 1800 1920 1760 0 im )o> ^ oj^k. Co, V Sample Cu A B C D E F 1 45.2 41.6 48.8 49.6 49.2 54.4 2 59.2 50.0 42.0 68.0 60.0 58.8 3 39.2 45.6 50.8 49.6 76.0 44.8 4 39.6 40.0 39.2 42.0 50.0 40.0 5 45.8 44.3 45.2 52.3 58.8 49.5 Pb A B C D E F 1 1440 1520 1120 2000 1520 1480 2 1400 1400 1200 1720 1880 1400 3 1400 1400 1320 1600 1800 1400 4 1440 1440 1200 2000 1680 1440 5 1420 1430 1210 1830 1720 1430 Zn A B C D E F 1 1780 1752 1872 1800 1720 1860 2 1800 1760 1860 1880 1800 1780 3 1752 1900 1840 1744 1816 1740 4 1760 1704 1920 1780 1860 1872 5 1773 1780 1873 1801 1800 1813 Cd A B D D E F 1 14.4 15.6 15.6 12.8 12.0 14.0 2 14.4 16.4 15.2 12.8 12.0 14.4 3 14.0 16.0 15.2 12.8 12.0 13.6 4 14.0 16.0 16.0 12.4 12.4 14.4 5 14.2 16.0 15.5 12.7 12.1 14.1 -509- 08/78/03 (contd.) Fe A B C D E F 1 3.28 3.32 3.12 3.04 3.40 3.32 2 3.20 3.44 3.20 3.20 3.36 3.32 3 3.20 3.40 3.20 3.16 3.24 3.24 4 3.32. 3.56 3.28 3.24 3.32 3.20 5 3.25 3.42 3.20 3.16 3.33 3.27 Mn A B C D E F 1 1880 2160 1920 1560 1920 1920 2 2000 1960 1640 2000 2160 1840 3 1880 2120 1880 1640 1800 1880 4 1920 2280 2000 1560 1840 2000 5 1920 2130 1860 1690 1930 1910 Ca A B C D E F 1 1.16 1.12 1.28 1.08 1.20 1.08 2 1.16 1.04 1.28 1.16 1.32 1.08 3 1.20 1.04 1.28 1.20 1.16 1.12 4 1.20 1.12 1.28 1.20 1.20 1.20 5 1.18 1.08 1.28 1.16 1.22 1.12 Mcl A B C D E F 1 4240 4000 4560 4080 4160 4240 2 4320 4200 4520 4080 4240 4080 3 4320 4280 4480 4080 4000 4080 4 4280 4200 4600 4000 4080 4120 5 4290 4170 4540 4060 4120 4130 Units : ppm except Fe and Ca which are expressed as % dry wt. -510- Results for HN0-, - HC10 „ Attack on Stream Sediments H Minsterley Brook - Occasion 10/78 Cu Pb Zn Cd Fe Mn Ca Mg 129 37 320 492 4 3.60 2080 0.35 5480 33 1100 29200 41200 3 28 0.69 5360 29.20 560 31 552 19600 19600 152 2.00 3120 14.40 29 20 30 384 •10800 14880 112 2.52 3200 10.40 4040 28 200 3840 6120 64 3.08 1600 4.84 53 20 107 172 3120 3440 33 2.76 1120 2.60 5000 10 224 2800 5040 54 2.80 1200 3.76 5160 9 88 1600 1640 14 2.92 1320 1.40 5280 3 54 1280 1360 13 3.36 1160 1.04 5200 126 - 134 21 376 664 5 4.48 1320 0.52 4400 105 28 1160 468 4 3.24 220 0.88 6480 29 26 1280 1520 15 3.12 1480 0.44 6240 132 18 120 196 1.6 4.00 1680 0.44 5600 02 16 176 216 1.2 3.92 560 0.24 48O0 River Ecclesbourne - Occasion 06/78 Cu Pb Zn Cd Fe Mn Ca Mg 352 120 2640 1600 28.8 2*40 760 10.00 4480 318 85 31200 3600 47.6 2.24 680 3.68 2760 328 55 4320 1520 20.8 2.92 840 3.12 3000 321 28 5520 876 11.2 1.92 720 1.04 1840 336 24 1840 520 6.0 2.04 880 0.68 1560 325 49 1320 680 7.2 4.92 1680 0.60 4200 327 25 748 400 4.0 2.64 960 0.32 2000 351 22 624 412 4.4 2.56 960 0.31 1720 331 21 52 107 1.6 1.68 360 0.15 2280 322 39 320 288 4.0 4.04 1160 0.33 3520 347 73 3120 1640 26.0 2.00 680 11.20 3680 315 63 1280 864 16.4 3.56 840 10.00 4760 0 Ccv Si f < 0 wlr -511- Analyses of Size Fractioned Sediments Minsterley Brook 33 Cu Pb Zn Cd Fe(ppm) Mn Ca (30 Mg A 15.5 1000 1450 13.8 1500 4300 21. 25 175 B 12.5 900 1600 16.3 1400 4250 21. 25 150 C 12.5 1675 2375 20.0 1475 4300 22. 00 150 D 14.5 2675 2275 27.0 1350 4300 21. 0 175 E 15.8 5300 2725 37.5 1350 4250 22. 25 175 F _ 16.0 5750 3000 46.0 1225 4750 - 31 Cu .Pb Zn Cd Fe Mn Ca Mg A 6.8 500 974 12.0 1140 3460 17. 20 160 B 8.4 780 1300 13.8 1080 3400 17. 00 140 C 9.6 1440 2000 19.6 940 3440 16. 80 160 D 13.0 4100 2120 27.0 760 3600 17. 00 180 E 35.6 14800 5000 38.4 2220 3640 14. 80 220 F 55.2 15400 6800 48.0 3420 2720 8. 20 300 28 Cu Pb Zn Cd Fe Mn Ca Mg A 10.0 660 1200 10.0 1800 3400 17. 20 256 B 12.4 1480 1900 15.0 3000 3200 14. 80 306 C 13.0 2240 2460 20.0 3200 2200 9. 00 324 D 15.2 2760 2860 35.0 3200 1840 6. 50 340 E 17.6 4600 3020 44.2 2800 1320 3. 88 400 F 22.0 2860 3700 52.4 2900 1180 2. 11 448 10 Cu Pb Zn Cd Fe Mn Ca Mg A 9.4 880 1960 8.4 2800 1760 8. 00 290 B 11.0 1180 2120 11.2 3700 2200 10. 00 426 C 13.4 1800 2680 15.4 4100 2200 8. 80 392 D 18.8 2960 3680 31.8 3400 1340 4. 99 572 E 18.0 2960 3600 37.0 2600 880 3. 05 782 F 21.0 2460 4300 54.6 2800 1440 2. 11 748 03 Cu Pb Zn Cd Fe(ppm) Mn Ca Mg A 11.0 660 700 4.2 4400 620 0. 94 300 B 10.0 720 860 6.8 5200 760 1. 38 358 C 11.0 820 860 8.6 4600 800 1. 66 374 D 14.0 980 880 10.2 2780 940 1. 33 306 E — 1180 1100 17.0 3400 1360 0. 98 578 F 17.0 880 1200 22.8 3000 1460 0. 61 544 o VAA.I/) C River Ecclesbourne 352 Cu Pb Zn Cd Fe(ppm) Mn Ca Mg A 31.4 1540 600 14.6 5200 520 14, 80 3740 B 40.0 1580 1200 23.6 5000 600 14. 20 3400 C 41.2 1940 840 19.0 5400 540 8. 80 1700 D 47.0 2360 720 17.2 4600 480 8. 00 1700 E 66.2 2820 1000 22.0 6800 700 8. 91 810 F 84.0 • 2660 1140 29.0 7600 960 9. 20 2040 328 Cu Pb Zn Cd Fe Mn Cu Mg A 19.9 3695 4375 71.5 5120 460 9. 92 1264 B 18.9 4040 2085 40.9 5580 488 9. 08 1348 C 18.1 3790 1400 24.7 4100. 435 4. 09 799 D 18.9 5440 705 12.2 3800 430 2. 24 527 E 38.1 5520 1100 20.6 7160 824 2. 79 846 F 53.7 4150 1764 34.3 8580 1176 3. 40 1066 336 Cu Pb Zn Cd Fe Mn Ca Mg A 45.2 1080 2460 33.6 1200 1440 1. 94 680 B 13.0 2000 1100 14.6 8600 1080 0. 89 408 C 7.8 1220 4220 6.0 4100 560 0. 39 27 2 D 9.0 1320 2480 4.4 3600 460 0. 33 204 E 14.0 1940 3260 6.80 5000 600 0. 50 306 F 31.0 1840 7200 15.6 9600 1740 0. 91 646 325 Cu Pb Zn Cd Fe Mn Ca Mg A 17.4 720 4520 4.0 9400 1440 0. 50 562 B 13.0 2920 4900 4.6 7400 880 0. 39 510 C 7.8 1740 2600 3.0 3400 580 0. 24 340 D 29.8 1900 2300 4.0 4800 760 0. 28 562 E 22.0 1800 3600 6.8 8200 1540 0. 54 1156 F 33.2 1440 5320 12.2 10400 2800 0. 80 163 2 321 Cu Pb Zn Cd Fe(ppm) Mn Ca Mg A 34.2 2920 1440 210 7600 1060 3. 00 554 B 23.4 2400 2820 57.8 7800 880 3. 77 816 C 10.0 2400 580 9.6 2880 440 1. 09 272 D 10.6 5200 380 7.0 2640 400 0. 57 188 E 15.2 1220 420 8.6 3700 560 0. 72 334 F 24.6 2040 720 17.0 5800 1020 1. 00 510 0 V\A )q y CCK Vo d^M ia/J"" . -513- Analyses of Control Samples of DIW Cu Pb Zn Cd Fe Mn 0.25 N.D. 1.1 0.1 4.5 N.D. 0.15 1.0 0.1 9.0 0.10 0.5 0.1 2.5 0.60 1.0 0.1 4.0 N.D. 2.5 0.15 7.5 1.25 0.25 N.D. 0.35 3.15 0.2 12.5 0.5 0.40 2. 5 5.55 0.4 7.5 N.D. 0.20 N. D. 3.4 0.15 N.D. 0.45 2.0 0.15 3.5 0.35 2.1 0.10 4.5 0.3 10.8 0.2 9.5 0.45 10.4 0.35 12.5 0.50 2.5 N.D. 3.65 0.20 1.1 0.2 1.0 0.3 12.5 N.D. 1.0 0.25 0.85 0.2 2.5 0.25 0.85 0.1 2.5 0.40 1.1 0.25 1.0 0.30 0.8 0.1 1.5 0.40 0.6 N.D. 2.5 O iAA A -514- Analyses of Spiked Samples of DIW Cu Pb Zn Cd Fe Mn Spike Conon 10.1 9.5 10.55 9.75 12.5 9.5 10 10.65 10.0 10.6 10.0 13.5 10.0 10 19.75 19.5 20.5 19.5 25.0 19.0 20 19.75 18.0 21.0 "19.5 26.5 18.0 20 10.25 11.0 11.25 9.90 11.65 9.6 10 10.25 11.0 12.25 10.25 12.75 9.60 10 8.80 9.5 10.0 9.50 12.0 9.0 10 9.50 9.0 10.65 9.00 12.5 10.0 10 21.0 19.0 23.0 20.0 23.0 19.5 20 21.0 18.0 21.0 20.0 27.5 20.0 20 20.0 18.5 21.5 20.0 21.0 18.0 20 24.5 22.5 26.5 25.0 32.5 25.5 25 20.3 19.0 23.0 20.5 25.0 21.0 20 21.0 19.5 22.5 21.0 26.0 20.5 20 20.5 20.0 22.5 20.0 26.5 21.0 20 o Percentage Recoveries from Spiked Samples of DIW 101 95 106 97.5 125 95 106.5 100 106 100 135 100 98.8 97.5 102.5 97.5 125 95 98.8 90 105 97.5 132.5 90 102.5 110 112.5 99 116.5 96 102.5 110 122.5 102.5 127.5 96 88 95 100 95 120 90 95 90 106.5 90 125 100 105 95 115 100 115 97.5 105 90 105 100 137.5 100 100 92.5 107.5 100 105 90 98 90 106 100 130 102 101.5 95 115 102.5 125 105 105 97.5 112.5 105 130 102.5 102.5 100 112.5 100 132.5 105 -515- Calcium Corrections Date Ca _ Apparent Concentration (ppm) Concen Zn Cu Pb Cd (ppm) 3/5/78 480 0.025 0.03 - 0.01 720 0.04 0.03 0.1 0.02 i200 0.06 0.04 0.2 0.03 2400 0.11 0.05 0.5 0.06 4800 0.21 0.08* 0.8 0.12 7000 0.29 0.10 1.1 0.17 30/5/78 720 0.04 0.02 0.1 0.02 1200 0.06 0.04 0.2 0.04 2400 0.12 0.06 0.5 0.06 4800 0.20 0.08 0.8 0.11 7200 0.27 0.12 1.2 0.16 1/8/78 720 0.05 0.02 0.2 0.02 1200 0.07 0.02 0.3 0.04 2400 0.105 0.05 0.5 0.06 4800 0.20 0.08 0.9 0.14 7200 0.27 0.11 1.4 0.20 12000 0.42 0.18 2.1 0.53 25/1/79 1200 0.06 0.03 0.3 0.05 2400 0.12 0.04 0.7 0.10 4800 0.21 0.08 1.3 0.17 7200 0.32 0.12 1.8 0.24 -516- Analyses of Replicate Subsamples of Stream Water from the River Ecclesbourne Sample Cu A B C D E 1 1.3 1.5 0.8 1.3 0.9 2 1.2 1.3 0.9 1.0 1.7 T 3 1.2 1.3 1.0 1.5 0.9 Replicat,i< e 4 1.0 1.4 _ 0.9 1.0 0.8 5 0.9 2.2 1.0 1.0 0.8 1 Pb A B C D E 1 5.0 5.5 5.0 4.5 5.0 2 5.0 7.0 5.0 5. Q 5.0 3 5.0 6.5 4.0 5.5 4.5 4 4.5 6.5 5.0 5.0 5.0 5 5.0 6.0 4.5 4.5 5.0 Zn A B C D E 1 21.5 37.5 17.5 19.0 17.0 2 23.0 40.0 21.0 19.0 19.5 3 22.0 38.0 18.5 20.0 16.0 4 23.5 40.0 16.5 20.0 16.5 5 21.5 39.0 17.0 18.0 17.0 Cd A B C D E 1 0.4 0.3 0.5 0.3 0.3 2 0.3 0.5 0.9 0.4 0.3 3 0.3 0.4 0.6 0.7 0.3 4 0.4 0.5 0.4 0.5 0.4 5 0.3 0.7 1.0 0.3 0.3 Fe A B C D E 1 30.5 30.0 29.0 29.5 30.5 2 29.5 30.0 29.5 29.0 30.5 3 30.0 30.0 29.0 33.0 28.5 4 30.0 30.0 28.0 30.5 29.0 5 30.0 31.0 29.0 29.0 29.5 Mn A B C D E 1 3.0 3.5 3.5 3.0 3.5 2 3.0 3.5 3.0 3.0 3.5 3 3.0 3.5 3.5 3.0 2.5 4 3.5 3.0 3.0 3.0 3.5 5 3.0 3.5 3.0 2.5 3.0 -517- Analyses of Standardised Sediment Sample M203 HNCU Attack Cu Pb Zn Cd Fe Mn Ca Mg 7.2 220 544 4.8 1.72 284 - - 6.8 264 712 6.0 1.84 344 -- - - 7.2 260 572 5.2 1.64 320 3.44 6160 8.4 256 • 644 4.4 1.84 320 3.40 6120 7.6 268 768 5.2 1.92 312 3.36 6120 7.6 280 632 5.2 1.92 300 3.28 6120 8.4 264 680 4.8 2.08 320 3.32 6120 8.4 256 632 4.0 1.96 316 3.28 6000 8.4 280 652 4.8 2.04 336 3.36 6040 8.0 288 780 4.8 1.96 324 3.48 5800 7.2 268 616 4.0 1.96 328 3.40 5720 8.0 264 600 4.4 1.96 304 3.32 5600 8.0 272 620 4.4 1.84 324 3.32 5800 8.0 288 780 4.4 2.00 324 3.36 6000 8.8 312 640 4.4 2.16 372 3.68 6000 0.5M HC1 Leach Cu Pb Zn Cd Fe Mn Ca Mg 2.6 180 256 3.2 0.10 240 3.60 5000 2.6 180 256 3.2 0.10 240 3.66 5000 3.0 180 232 3.4 0.86 220 3.56 5000 2.2 168 212 3.0 0.80 220 3.56 4600 3.2 184 244 3.2 0.98 220 3.20 4400 3.0 184 250 3.4 0.10 240 3.30 4600 2.8 186 242 3.2 0.10 240 3.32 4600 2.8 162 210 3.4 0.84 200 2.92 4260 2.4 162 220 3.2 0.88 200 2.92 4300 2.4 162 212 3.4 0.82 220 2.80 4320 2.4 160 204 3.4 0.82 200 2.88 4160 HC10 „ Attack hno3 - 4 Cu Pb Zn Cd Fe Mn Ca Mg 8.8 276 608 4.8 2.52 332 3.04 7040 9.2 276 588 4.8 2.44 344 3.20 7200 8.0 264 616 4.4 2.56 332 3.04 6600 L0.8 276 600 5.2 2.72 320 3.12 6800 9.2 284 572 5.2 2.64 324 3.08 6600 9.6 312 604 4.8 2.84 368 3.12 7200 LO.O 288 640 5.2 2.52 320 3.08 6760 8.0 340 720 4.8 2.6 320 3.12 6960 8.4 ,312 684 4.8 2.72 320 3.04 6840 C Analyses of Standardised Sediment Sample D319 HNCU Attack Cu Pb Zn Cd Fe Mn 6.8 . 760 168 2.0 1.20 300 6.0 760 160 1.2 1.16 292 6.4 760 148 1.6 1.16 280 5.5 752 146 1.6 1.12 312 5.5 840 170 2.0 1.12 320 5.5 708 154 2.0 1.08 304 6.0 760 144 0.8 1.12 312 6.0 840 184 0.8 1.12 300 0 va/A^ ^ p /) w\