Nitrates and Salinity CD No Maps

Bundesanstalt für Geowissenschaften und Rohstoffe

Nitrate hotspots and salinity levels in groundwater in the Central District of Botswana

by Horst Vogel, Kentlafetse Mokokwe, and Thato Setloboko

November 2004

TABLE OF CONTENTS Page

1 INTRODUCTION ...... 1

2 OBJECTIVES ...... 2

3 GEOGRAPHY OF THE STUD Y AREA ...... 2 3.1 Mining ...... 2 3.2 Physiography and geology ...... 3 3. 3 Climate ...... 6 3.4 Groundwater and water use ...... 6

4 GROUNDWATER QUALITY INDICATORS ...... 7 4.1 Salinity ...... 7 4.1.1 Total dissolved solids (TDS) ...... 8 4.1.2 Electrical conductivity (EC) ...... 8 4.1.3 Sodium (Na+) ...... 9 4.1.4 Chloride (Cl-) ...... 9 2- 4.1.5 Sulphate (SO4 ) ...... 10 - 4.2 Nitrate (NO3 ) ...... 11 4.2.1 Nitrate health problems ...... 11 4.2.2 Nitrate cycle in dryland environments ...... 12 4.2.2.1 Cattle posts ...... 13 4.2.2.2 Termites and ants ...... 13 4.2.2.3 Biological soil crusts ...... 14

5 METHODS AND MATERIALS ...... 14

6 RESULTS ...... 15 6.1 Groundwater nitrate hotspots ...... 16 6.2 Total dissolved solids in groundwater ...... 19 6.3 Selected groundwater salinity indicators ...... 19

7 DISCUSSION AND CONCLUSIONS ...... 20

8 REFERENCES ...... 22

9 APPENDICES ...... 27 I Map of groundwater nitrate hotspots ...... 28 II Map of total dissolved solids (TDS) in groundwater ...... 29 III Map of selected groundwater salinity indicators ...... 30 IV Guidelines for groundwater sampling ...... 31

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LIST OF FIGURES

Page

Figure 1: Administrative district boundaries in Botswana ...... 3 Figure 2: Physiographic units of Botswana ...... 4 Figure 3: The Makgadikgadi Pans complex ...... 5 Figure 4: Degraded landscape near Rakops, mid-Boteti area ...... 7 Figure 5: Fluctuation of nitrate concentrations in Kgagodi in 1998 ...... 17 Figure 6: Development of nitrate concentrations in Mathathane between 1979 and 2002 . 18 Figure 7: Nitrate concentrations at police station in Martin’s Drift ...... 18 Figure 8: Nitrate concentrations at Machaneng ...... 18 Figure 9: Chloride versus sodium concentrations at 1396 sites in the Central District ...... 20

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1. Introduction

The very first steps that eventually led to the preparation of this report date back to July 1999 when two of the authors visited the diamond mine in Orapa on a fact finding mission concerning environmental geology problems. While groundwater salinity was known to be conspicuous in many parts of Botswana, the reported high levels of nitrate were not clearly understood (Mokokwe, 1999).

That is why the Environmental Geology Division in October 1999 proposed setting up a nitrate research project that eventually commenced in 2001. The prime objective of this project is to investigate the processes that lead to nitrate enrichment in the Ntane sandstone aquifer between Serowe and Orapa. The quintessential findings of this research project are that cattle posts, pans, and termite mounds are definitely locations of extreme nitrate enrichment in soils but the observed highly heterogeneous nitrate distribution in groundwater could not be attributed to obvious point sources (Stadler et al., 2004a).

During the intervening time, that is prior to the commencement of the nitrate research project, the Environmental Geology Division embarked on a first groundwater sampling campaign in the area between Serowe (recharge area) and Orapa (discharge area). She also began to compile groundwater quality data from external sources, in particular from the Department of Lands. These activities led to the compilation of a digital draft map on groundwater quality in the Ntane sandstone aquifer between Serowe and Orapa (Mokokwe & Wolff, 2001). The map depicts the spatial distribution of nitrates and total dissolved solids (TDS) along with piezometric surfaces and water types, though based on a limited data pool. Because both staff moved on shortly after the draft map was made, both the study and the map were not finished.

A parallel stepping stone in collecting data was an in-depth study into the environmental hydrogeology of Orapa (Matthes, 2002). No hard-and-fast conclusions could be drawn from this study with regards to the origin of nitrates. But there were indications that up-welling of groundwater (along fault lines and/or fractured zones in dolerite dykes ) from strata deeper than the Ntane sandstone could be a source of increased nitrate levels in the Ntane sandstone. Another possible source of nitrates in the immediate vicinity of the open pit was assumed to be explosives used in pit blasting.

Similar assumptions emerged from a second in-depth study that was carried out at the neighbouring diamond mine and village of Letlhakane (Keipeile, 2004) . This study also confirmed that nitrate levels in the groundwater pumped from the Ntane sandstone aquifer were highly variably. Some had very low concentrations, while others featured high ones.

An opportunity to collect data in an adjacent area arose through a collaborative exercise with the Department of Water Affairs (Setloboko, 2003). This study provided access to data from the area of the river Boteti, which until lately used to discharge remnant water from the Okavango delta into the Makgadikgadi Pan complex of the Central District. The study concluded that there was no clear-cut correlation between nitrate levels and land use, and that most nitrates occurring in the study area could be of biogenic origin.

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2. Objectives

The objectives of this report are manifold. First and foremost it assesses important groundwater quality indicators against the national water quality guidelines for drinking water (BOS, 2000) with a view to provide guidance to groundwater users, policy makers, and those government agencies in charge in one way or the other of groundwater resources. This objective goes hand in hand with the attempt to provide guidance levels on these groundwater quality indicators for livestock watering.

Second, the study intends to highlight the wealth of data that already exists within various government departments and private consultancy firms alike. Most often these data rest idle once the particular project, which had led to its collection and/or generation, has come to an end. Yet, such data may be collated into data bases, reports, and geographic information coverage for further regional and national elucidation.

Third, the study aims to highlight the usefulness of maps in assisting with water quality planning and research efforts. If put into Geographical Information System (GIS) formats, such maps may easily and readily be updated and improved upon as new data becomes available.

3. Geography of the study area

The study area covers the entire Central District (Fig. 1) plus a small portion of the Ngamiland District east of Gweta and around Motopi. The Central District is the heartland of Botswana, in particular when it comes to her breathtaking economic development over the last three decades (cf. BNA, 2001; Solomon, 2000; Coakley, 2001 and 2002).

3.1 Mining

The diamond sector, which continues to be the mainstay of Botswana’s economy, was born in the Central District. The discovery of the Orapa diamond mine by De Beers’ geologists in April 1967 and commencement of mining in 1971 marked the beginning of the country’s economic upturn.

In 2004, Debswana Diamond Co. (Proprietary) Ltd. produced diamonds in the Central District from the original Orapa and Letlhakane mines plus the newly commissioned Damtshaa mine, which is also located within the Orapa -Letlhakane diamond province. Thus three out of four diamond mines in Botswana are located in the Central District. In fact, over 55 kimberlite pipes are known within the Orapa -Letlhakane province, which is located within the 2.5 billion year old Kalahari Craton and kimberlite emplacement age is Late Cretaceous (approx. 90 million years). A feature of this region are dolerite dykes that reflect a major crustal weakness. The regional geology is dominated by Stormberg basalt and Ntane sandstone.

Nickel, copper, soda ash, and coal production also play significant though smaller roles in the national economy. They are also all located within the Central District. The second biggest mining company after Debswana is BCL Limited (formerly Bamangwato Concessions Limited), which produces copper, nickel, and cobalt, and operates a concentrator and smelter at Selebi-Phikwe. The Selibe-Phikwe base metal mine is located on a contact zone of intense mineralization at the edge of a large Gaborone Granite formation, which is part of the Kalahari Craton.

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Figure 1: Administrative district boundaries in Botswana (Source: http://eol.jsc.nasa.gov - modified)

Botswana Ash (Proprietary) Ltd. (Botash) pumps salt brines from nearly 100 wells to nearby large evaporation ponds at Sowa Pan. The Botash soda ash and salt extraction plant is situated on a spit at the north-eastern edge of Sowa Pan, which is part of the Makgadikgadi Pan complex, one of the largest salt pans in the world .

In addition, the country has coal reserves in the Karoo System rocks in the Central District, which are mined by the Morupule Colliery (Proprietary) Ltd. at Morupule. The thermal power plant at Morupule supplies more than 50 % of Botswana’s electricity requirements. Apart from this, the colliery supplies both BCL and Botash with coal for their operations. This makes the mine a critical component of the country’s mineral diversification programme despite its comparatively small size and low quality produc t.

3.2 Physiography and geology

The Central District is dominated by four physiographic units, namely the hardveld to the East, the sandveld (Kalahari) to the West, the Makgadikgadi Pans complex to the North, and, complementary to the latter, the alluvial systems of the rivers Boteti and Nata (Fig. 2; May, 1985; BNA, 2001).

The hard- and the sandveld are separated along the Eastern Escarpment, which zigzags in roughly NE-SW direction and cuts through the western fringe of the administrative district center of Serowe. The smaller hardveld region owes its name to the fact that the rock of this area is near the surface, so there is also surface flow of water. The region is characterized by

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inselbergs and sand rivers, which drain to the river Limpopo. The Limpopo basin is located over the northern part of the Kalahari Craton, with the Limpopo river valley marking the approximate position of the Limpopo Mobile Belt where considerable mineralization has taken place (Ashton et al., 2001). The Archaean Craton rocks comprise predominantly crystalline granitic and gneissic rocks, intruded by various Greenstone belts as well as dolerite dykes and sills.

Figure 2: Physiographic units of Botswana (Source: BNA, 2001)

The Motloutse, Lotsane, and Mahalapye are the largest sand rivers in the Central District. They rise in a range of low hills at the eastern edge of the Kalahari and flow eastwards to the Limpopo. Water flow in these sand rivers is entirely seasonal or episodic , but despite their ephemeral flow these rivers are an important source of water locally, due to the reliable groundwater reserves within their beds. All settlements in the hardveld region rely on whatever water they can obtain from the local sand rivers, as well as an extensive system of boreholes. The cities and large villages nowadays draw much water from the North-South Carrier pipeline, which is fed by the Letsibogo dam along the river Motloutse close to Selebi- Phikwe.

The rocks of the Kalahari Craton underlie the Precambrian hardveld region in the Central District (Ashton et al., 2001) . Large areas have exposures of Gaborone and Mahalapye

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granites, as well as rocks of the Palapye Suite and the Lebung Formation of the Karoo System.

Most of the sandveld region is covered by sediments of the Kalahari beds. The Kalahari beds are comprised of unconsolidated to semi-consolidated fine- to medium-grained sands, silty sands, sandy silts, silcretes, calcretes, and silts interlayered with clays (Thangarajan et al., 1999). The dominant sands, which comprise both windblown sand and, in the north, sand from river and/or lake deposition, take in rain fairly swiftly, so that surface water is rare. This sedimentary cover is of Tertiary to recent age, and it provides the region with an elevation of approximately 1,000 m, with very little variation. The Kalahari plateau extends across much of central Southern Africa.

Over the sandveld region, surface drainage and groundwater recharge by direct rainfall infiltration is mainly restricted to pans (shallow depr essions) and dry valleys. Throughout the Kalahari plateau there are thousands of pans, which hold water for short periods of time after good rains. It is interesting to note that the initiation and location of the pans is thought to be controlled by geological structure since they are prominently located along distinct trends that can be related to previously recognised regional-scale fracture/fault sets (Wormald et al., 2003).

Figure 3: The Makgadikgadi Pans complex (Source: http://eol.jsc.nasa.gov - modified)

One of the largest saltpan complexes in the world, the Makgadikgadi Pans, dominate the northern part of the Central District (Figure 3). The complex consists of two major pans, namely Ntwetwe Pan and Sowa Pan. Sowa Pan is sustained by freshwater from the river Nata, which originates in Zimbabwe to the East and is the most important river in the complex. The bigger Ntwetwe Pan used to receive inflow from the river Boteti. The Boteti used to irregularly flow out of the Okavango Delta through a break in the Thamalakane fault

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(southern extremity of the East African Rift Valley) and emptied into the southern portion of Ntwetwe Pan (cf. Fig. 1). However, for the last two decades the Boteti has been dry except for isolated pools of water.

3.3 Climate

The Central District lies in a semi-arid environment that is characterized by overall low rainfall and low air humidity, high summer temperatures, and thus high rates of potential evapotranspiration (cf. Thomas & Shaw, 1991; BNA, 2001). The rainy season occurs in summer and lasts from October to March with periodic drought being typical. Not only is the annual rainfall low, but it also has a high spatial and temporal variability. Lots of rains fall as rather localize d thunderstorms of high intensities. Singular downpours delivering up to 100 mm and more within a few hours are possible.

Mean annual rainfall in the Central District ranges from about 400 mm in the East to 500 mm in the North, with approximately 50 % variability from year to year. Droughts are frequent and occur in two years out of five. Severe droughts can be expected in an approximately seven-year cycle.

Temperatures are typical of a continental climate, with high diurnal and seasonal ranges. In winter (June/July), early morning temperatures may drop below freezing, in particular in the Kalahari, while in summer (December/January) temperatures may exceed 40° C.

3.4 Groundwater and water use

Botswana is a water-stressed country. Because of very limited surface water, most of the human and animal populations are dependent on groundwater. Traditionally, groundwater abstraction took place by means of shallow hand-dug wells of usually no more than 10 m depth (BNA, 2001). However over the past three decades the massive extension of deep drilled boreholes has become the common method of groundwater exploitation. Close to 20000 boreholes are now registered with the National Borehole Archive.

The livestock sector is a major consumer of groundwater in the Central District, as is the mining industry. In the Orapa-Letlhakane area huge amounts of groundwater are being extracted for mining purposes. Similarly, close to Serowe (Paje), groundwater is mined for use by the Morupule Power Station.

A major problem in the livestock sector is that the unplanned ad hoc drilling of boreholes continues without any real control. Owing to the steady expansion of boreholes, extensive seasonal livestock production has increasingly been replaced by intensive permanent production systems. Also, the drilling of deep boreholes in the Kalahari has substantially increased the spatial distribution and density of livestock and in its wake spread conditions of overstocking and environmental degradation on a large scale (Darkoh, 1997). An area particularly hard hit since the 1980’s is the region along the river Boteti, where desertification is wide-spread (Fig. 4) and groundwater resources steadily deteriorate both in quantity and quality. Country-wide, the present reliance on groundwater cannot be sustained in future (ADB, 1995) . The growing water shortage in Botswana prompted the construction of the North-South Carrier, a pipeline system that carries water from the Motloutse River (Letsibogo dam) southwards to the capital of Gaborone.

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Figure 4: Degraded landscape near Rakops, mid-Boteti area.

4. Groundwater quality indicators

Salinity and nitrates have been selected as general indicators of groundwater quality (chemistry) in the Central District because they are of major concern in this semi-arid environment. In addition, they are some of the few parameters with long data records.

4.1 Salinity

Salinity is a measure of the concentration of inorganic and organic matter dissolved (ionized) in water (cf. Appelo & Postma, 1999; Hitchon et al., 1999). It is measured by a variety of methods and units but is generally reported as total dissolved solids (TDS) in mg/L. The surrogate, EC (electrical conductivity), is a measure of the electrical conductivity of water expressed as µS/cm (EC units) at 25 degrees celcius (°C).

2– Because it is difficult to simplify salinity to just one or two parameters, sulphate (SO4 ), chloride (Cl-), and sodium (Na+) were also employed in this study. Especially sodium and chloride levels are of great concern when it comes to salinity in groundwater that is earmarked for agricultural purposes.

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4.1.1 Total dissolved solids (TDS)

Total dissolved solids (TDS, also called total filterable residue ) is defined as the quantity of dissolved material in water, and depends mainly on the solubility of rocks and soils the water moves through. Water is a good solvent and picks up impurities easily as it travels along mineral surfaces in the pores or fractures of the unsaturated zone and the aquifer. Some dissolved solids may also originate from the rainwater (cyclic salts) or river water that recharges the aquifer.

Except for some small amounts of organic matter originating from soils, all of the naturally occurring dissolved solids are inorganic constituents, namely minerals, nutrients, and trace elements including trace metals. A list of dissolved solids in any water is long, but common dissolved solids are sodium, chloride, sulphate, calcium, bicarbonate, nitrate, and phosphate.

The most important aspect of TDS with res pect to drinking water quality is its effect on taste (palatability of the water). The palatability of drinking water with a TDS level less than 450 mg/L is considered to be ideal (BOS, 2000). At a high TDS level, groundwater becomes saline. The maximum allowable TDS level for drinking water in Botswana is 2000 mg/L.

At even higher TDS concentrations, water can also start to cause problems with the health and growth of livestock. A level of 10000 mg/L is considered unsatisfactory for all classes of livestock (Jaikaran, 1993; Bauder, 1998; Thiex & German, 2004).

Although high TDS levels do not per se mean that the water is a health hazard, some of the individual components of TDS such as nitrates can have adverse effects on human health. Also, with regards to trace metals, elevated TDS concentrations may suggest that toxic metals may be present. Hence, high TDS concentrations warrant getting a clear understanding of their cause.

4.1.2 Electrical conductivity (EC)

Electrical conductivity (EC) and TDS are two separate measures of the same thing. They measure the presence of all negatively charged ions (anions) and positively charged ions (cations) in water, yet in different ways. But like TDS, EC also does not give specific information about the chemical species present in the water.

In natural groundwater, anions and cations are present in balanced proportions that are determined by equilibrium between the solution and the geologic formation. The presence of these mainly inorganic chemical constituents gives water the ability to conduct electricity. Organic compounds like oil, phenol, alcohol, and sugar do not conduct electrical current very well and therefore have a low conductivity when in water. EC is thus dependant upon the total and relative concentrations of ions, their valence, and mobility.

Unlike TDS, EC is also dependent on temperature, increasing by about 2 percent for each 1°C for most water types. For this reason, conductivity is reported at 25 °C. EC is the reciprocal of electrical resistivity and, for drinking water, is expressed in terms of microsiemens (mS) per centimeter.

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EC and TDS are related, but the relationship is not a constant. In reality it is a function of the type and nature of the dissolved constituents and possibly the nature of any suspended materials. The relationship between EC and TDS for dilute solutions is:

TDS (mg/L) = ƒ × EC (µS/cm), where the proportionality constant, ƒ, varies between 0.55 and 0.85, depending on water type (DEH, 2003).

The Botswana drinking water standard classifies an electrical conductivity (specific conductance) of up to 700 µS/cm as ideal, up to 1500 µS/cm as acceptable, and 3100 µS/cm as maximum allowable concentration (BOS, 2000).

4.1.3 Sodium (Na+)

As mentioned, TDS and EC levels do not tell the nature of the ions present nor ion relationships. These tests also do not provide insight into specific water quality issues such as salty taste, corrosiveness, or irrigation water suitability. To address such aspects individual constituents need to be looked into.

As far as human drinking water supplies are concerned, the major concern with salt pollution of groundwater is the potential threat to human health through increased sodium levels. Sodium in drinking water is not a health concern for most people but may be an issue for someone with high blood pressure, kidney disease, or on a sodium-restricted diet. Yet, the amount of sodium in drinking water is normally insignificant compared to the sodium consumed in the average diet. As no firm conclusions can be drawn regarding the health effects of sodium, no health-based guideline value has been derived (WHO, 1993).

Sodium concentrations in excess of 200 mg/L usually produce a noticeable taste in drinking water. This constitutes the acceptable upper limit according to the Botswana drinking water standard, while the maximum allowable concentration is 400 mg/L (BOS, 2000).

Sodium is particularly important in irrigation because it can have very adverse effects on soil physical structure and plant growth even when overall salinity is low. Soils with a high concentration of sodium are notorious for reduced permeability, drainage, trafficability, and increased erodibility.

High levels of sodium may also cause plant toxicity or induce deficiencies of other elements. A toxicity problem is different from a salinity problem in that a toxicity occurs within the plant itself as a result of the uptake of certain constituents from the irrigation water. The toxic constituents of particular concern are sodium, chloride, and boron. Toxicity symptoms of sodium and chloride can occur with almost any crop if concentrations are high enough. They often accompany and complicate a salinity problem (www.clemson.edu/agsrvlb/IRRWAT. htm).

4.1.4 Chloride (Cl-)

Chloride, sulphate, and bicarbonate are the three most common anions in groundwater. If the water contains high levels of chloride it will usually have high levels of sodium, however the reverse is not true . The reason for this is that chloride in groundwater normally originates

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from the dissolution of halite (NaCl) and related minerals (Hem, 1985). Close to settlements, chloride is indicative of anthropogenic contamination in the form of human, animal, and/or industrial wastes.

High concentrations of chloride give an undesirable taste to water. Taste thresholds for chloride depend on the associated cation and are in the range of 200–300 mg/L for sodium, potassium, and calcium chloride. The acceptable upper limit in Botswana is 200 mg/L, while the maximum allowable concentration is 600 mg/L (BOS, 2000). Again, no health-based international guideline value has been proposed for chloride so far (WHO, 1993).

Water high in chloride is very corrosive. It may damage plumbing and water heaters. Where only water of very high natural chloride content is available, reverse osmosis or electro- dialysis units may be used to produce potable water.

Chloride behaves similarly to sodium in the plant giving similar toxicity symptoms. Chloride- sensitive plants may experience burning of leaf tips and/or margins, and leaf splitting. In addition, reduced root growth leads to lower plant growth rate.

2– 4.1.5 Sulphate (SO 4 )

2– Sulphate, measured as SO 4 , is the most common form of sulphur in natural waters (Hem, 1985). Hexavalent sulphur (S6+), a non-metallic element that occurs naturally in numerous 2- minerals, combines with oxygen to form the divalent sulphate anion (SO4 ). Possible mineral sources of sulphate include evaporite minerals such as gypsum (CaSO 4-2H2O) and anhydrite (CaSO 4), and other minerals such as barite (BaSO4), celestite (SrSO 4), epsomite (MgSO4- 1 7H2O), marcasite (FeS2), pyrite (FeS2), arsenopyite (FeAsS), and chalcopyrite (CuFeS2).

The amounts in groundwater are related primarily to dissolution or weathering of these naturally occurring minerals in geologic deposits and soils in the recharche area. Another source of sulphur in deep groundwater includes decomposition and combustion of organic matter, for example from coal deposits. Atmospheric sulphate input has become a major indicator of sulphur dioxide (SO2) air pollution.

As sulphate is one of the least toxic anions, no health-based guideline value has been derived (WHO, 1993). But big amounts of sulphate in combination with other ions (especially sodium) can cause bad odours and a bitter taste to water. Sulphates also may clog plumbing due to scale build -up in water pipes and stain clothing. In addition, sulphate occurring in groundwater as magnesium sulphate (Epsom salt) and sodium sulphate (Glauber's salt) can have temporary laxative effects (diarrhea) on humans and livestock not used to the water (cf. Jaikaran, 1993; www.ianr.unl.edu/pubs/water/g1275.htm). This can lead to dehydration and is of special concern for infants and young livestock. With time, however, people and livestock will become used to the sulphate and the symptoms disappear.

Sulphate is important as an oxidant (electron receptor) and can be reduced to sulphide (S2-) and hydrogen sulphide (H2S) gas under reducing, low or zero oxygen conditions (Hem, 1985; White, 2003). Hydrogen sulphide produces an offensive rotten-egg odour and taste in the water, especially when the water is heated (heat forces the gas to escape into the air). Sulphate -reducing (sulphide -producing) bacteria, which use sulphur as an energy source in

1 Pyrite is a polymorph of marcasite, which means that it has the same chemistry (FeS2) as marcasite but a different structure and, therefore, different symmetry and crystal shapes. - 10 -

their metabolism of organic matter, are the primary producers of large quantities of hydrogen sulphide in deep wells and aquifers. Hydrogen sulphide is corrosive to metals and, if oxidation to sulphuric acid occurs, concrete pipes.

The Botswana Bureau of Standards has adopted a concentration of 400 mg/L as the maximum allowable concentration of sulphate in drinking water (BOS, 2000). Reverse osmosis, ion exchange, or electro-dialysis can be used to reduce sulphate concentrations.

- 4.2 Nitrate (NO3 )

- Nitrate (NO3 ) is the end product of oxidation of nitrogen (N) in the soil environment and is an essential plant nutrient (cf., for example, Schimel et al., 1997; Vogel, 2002; White, 2003). Nitrogen cycles through the soil, moving through a series of soil mineralization steps from + - - organic matter to ammonium (NH4 ) to nitrite (NO2 ) to nitrate (NO3 ) as it is broken down by bacteria. This conversion of nitrogen to nitrate in the soil by bacterial processes is termed nitrification.

In water, nitrate is undetectable without testing because it is colourless, odourless, and tasteless. Like chloride, nitrate is not adsorbed by soils and biodegrades but readily moves with water through the soil profile. If there is excessive rainfall, nitrate will be quickly leached below the plant's root zone and may eventually reach groundwater. Once there, it is hard to remove.

Nitrate in groundwater may result from both natural and anthropogenic sources, which in turn may be point or non-point sources. Frequently identified point sources are, for example, sewage systems and livestock facilities, while fertilized cropland and nitrogen-bearing bedrock are examples for non-point sources.

4.2.1 Nitrate he alth problems

Nitrate is a good indicator of groundwater quality because of the associated health problems. Although nitrate itself is a relatively non-toxic substance, bacterial conversion of nitrate to nitrite poses a real health hazard. This bacterial conversion occurs in the environment, in foods, and in the human mouth and gastrointestinal tract.

Nitrate converted to toxic nitrite oxidizes iron in the haemoglobin of the red blood cells to form methemoglobin, which lacks the oxygen-carrying ability of haemoglobin. This reduces the blood’s ability to transport sufficient oxygen from the lungs to individual cells of the body, a condition known as methemoglobinemia. Sometimes it is also referred to as “blue baby syndrome” because it mostly affects infants in whom it is visible in form of a blue skin tone. The condition leads to shortness of breath, heart attacks and suffocation and, if untreated, can be fatal.

In most humans the enzyme systems for rapidly reducing (metabolizing) methemoglobin back to oxyhemoglobin are intact. Hence, the total amount of methemoglobin within the red blood cells remains low even during periods of relatively high levels of nitrate/nitrite intake. But apart from infants, pregnant women, nursing mothers, elderly people, and even livestock are at risk of nitrate poisoning.

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The World Health Organisation (WHO, 1993) and the Botswana Bureau of Standards (BOS, 2000) have set a maximum contaminant level of 45 mg/L for nitrate in drinking water. When measured as nitrate-nitrogen, the limit is 10 mg/L (cf. Vogel, 2002).

If a water source features excessive nitrate levels, there are two basic choices. Either an alternative water supply is made available, or else, the water needs to be treated so as to remove the nitrate. In industrialise d countries, nitrate is generally removed from drinking water by means of distillation, reverse osmosis, or ion exchange. But these three methods are relatively expensive since they require ex situ treatment plants. That is why cheaper in situ methods are being researched and developed that may provide a viable, cost-effective alternative (Tredoux et al., 2004).

4.2.2 Nitrate cycle in dryland environments

After water, nitrogen is often assumed to constitute the second most limiting resource for plant growth in dry environments (Heaton, 1984). Yet, substantial quantities of nitrogen, as – NO3 , are known to get flushed through the unsaturated soil zone in dry regions by occasional deep-wetting leaching events during particularly heavy rainfall years (Barnes et al., 1992) . This episodic soil flushing has led to the accumulation of large reservoirs of nitrates in subsoil zones of dry environments throughout the world over the last 11000 years, that is during the Holocene (Walvoord et al., 2003).

– Why is not all NO3 N produced in dryland soils and assumed to constitute a limited plant nutrient consumed by plants but rather leached into deeper subsoil levels? The hypothesis is postulated that water-limited systems experience increases in their nitrogen pools (Swap et al., 2004). These pools are then subject to microbial processes at two levels: (1) almost constant, background activity at slow rates during extended dry periods and (2) intense episodic activity at high rates during the onset of the rainy season. Pos sibly because of the scarcity of denitrifying bacteria and limited bio -available carbon reserves during prevailing long dry spells (Barnes et al., 1992) , the more arid ecosystems appear to have a more open N cycle (open to losses of excess N), with more losses relative to turnover as total rainfall decreases (Aranibar et al., 2003).

Obviously, large subsoil nitrate pools also have implications for groundwater quality, in particular as far as shallow groundwater is concerned (Walvoord et al., 2003). Evidence from all over the world confirms that high nitrate concentrations are a widespread natural phenomenon of groundwater in semi-arid and arid regions, albeit spatially highly variable (Heaton, 1985; Barnes et al., 1992; Edmunds & Gaye, 1997; Tredoux, 2004). High spatial variability in groundwater quality is indicative of point sources of pollution and/or distinct preferential flow patterns (Heaton, 1984; MAF, 2000) .

In the absence of immediate human pollution there are several other potential sources for high nitrate levels in groundwater in dry environments, namely rain and dry atmospheric deposition of cyclic nitrate salts, fixation of atmospheric dinitrogen (N2) by nodulation on the root system of leguminous plants followed by mineralisation and nitrification processes in the soil, geologic nitrate loading from nitrate -bearing minerals in bedrock or evaporite deposits, and animal waste (Heaton et al., 1983; Barnes et al., 1992; Edmunds & Gaye, 1997; Holloway & Dahlgren, 2002). In the case of Botswana, leaching of animal waste at cattle posts, and nitrate fixation by bacteria in termite mounds and bacteria in biological soil crusts provide likely explanations.

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4.2.2.1 Cattle posts

Recent deep soil profiling in the Central District of Botswana revealed high concentrations of nitrate in kraals and next to watering tanks at cattle posts (Schwiede et al., 2004; Stadler et al., 2004a). At such sites the average concentration recorded was 54 mg NO3-N per kg of dry soil. With growing distance from the cattle posts levels dropped off sharply. At a distance of more than 1000 meters from the cattle post the measured concentration was only 1 mg NO3-N/kg soil. The latter figure, assumed to represent the natural background level, was still higher than expected for the prevalent sandy soils in this semi-arid environment.

Nitrate leaching is generally greatest in aerated, freely draining coarse-textured sandy soils, although poorly drained heavily textured soils such as Vertisols may also experience high losses in the presence of large deep vertical cracks (MAF, 2000; Vogel, 2002). In the absence of such cracks, poorly drained soils are bound to experience reduced nitrate leaching losses because of enhanced gaseous losses in the wake of denitrification (soil nitrate is converted to nitrous oxide ). In contrast, denitrification is likely to be insignificant under the oxidizing conditions of most dry environments, where under normal conditions the levels of both soil water and organic C are low.

The herding together of cattle in kraals and their moving together at watering points supplies leachable nitrogen, mainly urine, to the soil in a concentrated form (Heaton, 1985; MAF, 2000). Grazing animals excrete 70 % of the nitrogen they ingest in urine and 30 % in manure. Urine may contain up to 20 % nitrogen as mainly urea or ammonia. Outside the body, urea is also quickly converted into ammonia, which will be easily oxidized by nitrifying bacteria into nitrates, or else, may escape into the atmosphere.

The potential for nitrate leaching losses from such urine spots is very high. Up to 60 % of nitrogen is being volatilised or leached at urine spots (MAF, 2000). The localized return of nitrogen in urine spots creates biogeochemical hotspots and thus high spatial variability in the amounts of nitrate leached from different portions within cattle-grazed areas.

In contrast, the potential for leaching losses from non-urine patches in grazing areas is relatively small. First, because the solid waste of cattle contains much less nitrogen than urine does. Second, because nitrogen in manure is predominantly in the organic form of stable proteins. Unlike the inorganic ammonia, the organic form is only slowly released as mineral nitrogen, which in turn is largely taken up by plants or lost to the environment in pathways other than leaching (MAF, 2000).

4.2.2.2 Termites and ants

The aforementioned deep soil profiling in the Central District also revealed high concentrations of nitrate associated with termite mounds (Schwiede et al., 2004; Stadler et al., 2004a). At the base of termite mounds extremely high concentrations of up to 750 mg NO3-N per kg of soil were measured. In between two termite mounds the concentrations were comparable to the levels found under natural vegetation.

Similar results come from other dryland environments worldwide. Research studies in Australia on termite mounds (Barnes et al., 1992) and in the USA on ant nests (Wagner, 1997; Wagner et al., 1997; Wagner et al., 2004; Wagner & Jones, 2004) confirm that such sites do indeed also constitute biogeochemical hotspots.

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Bacteria associated with the termites appear to fix nitrogen, which eventually appears in an inorganic form, mainly as ammonia. This ammonia is in turn oxidized by other bacteria to nitrate and leached to the mound surface by capillary action. Sporadic soil flushing due to extreme rainfall events may eventually flush the nitrate down into the groundwater (Barnes et al., 1992).

The modifying effects of ants on the soil are perhaps less substantial than those of termites, especially when it comes to underground tunnelling, but soil from beneath plants with ant nests were also found to contain significantly higher concentrations of ammonium and nitrate. Similarly, soil from nest mounds also had significantly higher nitrogen mineralisation rates (Wagner, 1997). The mineral N concentration was found to be 600 to 800 % higher in ant nests than surrounding soils (Wagner et al., 2004). Ant nests also contained high concentrations of organic C and available P (Wagner & Jones, 2004). Nest mounds thus generate strong spatial heterogeneity in soil chemistry in arid grasslands.

4.2.2.3 Biological soil crusts

Biological soil crusts are dominant features of many dryland ecosystems worldwide (Evans & Belnap, 1999). Yet, few people are aware of the existence of biological soil crusts, let alone their status as one of the most important biological entities found on arid and semi-arid lands.

Biological soil crusts are concentrated in the top few mm of soil. They are formed by microscopic organisms (cyanobacteria, algae, micro-fungi, lichens, and mosses) and their by- products, creating a crust of soil particles bound together by organic materials. (Johnston, 1997). This soil microbial community and interactions between soil microorganisms and plants can control ecosystem nitrogen cycling. Soil microbes are the dominant force behind the nitrogen cycle in soil and their activity may determine the amount of nitrogen available for plant uptake (Hawkes, 2003).

Biological soil crusts are well adapted to severe growing conditions, but poorly adapted to livestock trampling. Trampling breaks up the sheaths and filaments holding the soil together and drastically reduces the capability of the soil organisms to function, particularly in nitrogen fixation (Johnston, 1997). Nitrogen fixation by soils along animal trails was found to be significantly lower than the overall average crust fixation (Hawkes, 2003).

Although biological soil crusts have been widely studied all over the world, only little information is as yet available for Southern Africa. One study, carried out in the year 2000, reported that nitrogen fixation by soil crusts was generally low and lower than in most other drylands (Aranibar et al., 2003). This finding may, however, have been influenced by the exceptionally high rains that fell in 2000. The same study suggests that plant types or individual species affect N cycling in the soil (Aranibar et al., 2003).

5. Methods and materials

The data for this report were gathered from various sources. Starting point were studies carried out by the Environmental Geology Division (Matthes, 2000; Keipeile, 2004) including one that up to now had only yielded a draft map for a spatially confined area (Mokokwe & Wolff, 2001), and an MSc study that had been initiated and supported by the division (Setloboko, 2003). The data from these studies were complemented by pulling together data from the national borehole archive data sets at the Dept. of Water Affairs in Gaborone and the

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Dept. of Geological Survey in Lobatse. In addition, data were collected from private consultancy firms that had carried out projects in the Central District. These comprised Hydrogeo Consultant, Water Surveys Botswana, and Wellfields Consulting Services.

All data were thoroughly screened for their suitability. Out of close to 10000 records that were initially available, just 2001 were utilized in the end. The reasons for this were manifold but often boiled down to poor recording during sampling and/or poor record keeping. A point in case was frequently inaccurate recording or even total absence of geographical coordinates, which rendered the data useless. Similarly, 1155 records stated that the year of sampling had been 1900. These records were also discarded.

Three maps were produced from the above data records employing the ESRI (www.esri.com) GIS software ArcView (Vers. 3.2) (Appendices I, II, III). First, a map on groundwater nitrate hotspots (Appendix I), which not only depicts sites that featured alarmingly high and thus - potentially health-hazardous nitrate (NO3 ) concentrations but provides information on all concentration ranges encountered. Second, a map showing the amount of total dissolved solids (TDS) in the groundwater, which is the prime indicator of gr oundwater salinity risk (Appendix II). Third, a composite map depicting additional key salinity indicators, namely - + 2- electrical conductivity (EC), chloride (Cl), sodium (Na ), and sulphate (SO 4 ) (Appendix III). Without doubt, the level of salinity is the most common groundwater quality concern in Botswana, especially chloride, sodium, and sulphate levels.

The hardcopies of all three maps are of size A0 and feature a recent satellite image as backdrop. This satellite image has been removed from the attached maps (Appendices I-III) except for the inlays of the map of nitrate hotspots so as to reduce the digital size of the report. For the first time, the maps were saved in the PDF format in the GIS software environment rather than as image files. This allows to zoom into the maps on screen and for excellent print quality both free of blur.

The legends for all three thematic maps were developed with regard to potential health hazards to humans and livestock, and the suitability of groundwater for drinking and other uses. The basic approach was to employ the upper threshold levels (maximum allowable concentrations) as per the Botswana drinking water standard (BOS, 2000). Classification beyond these threshold levels was done on the basis of information that was gleaned from various Internet sources (Jaikaran, 1993; Zublena et al., 1993; Bauder, 1998; Stoltenow & Lardy, 1998; Undersander et al., 2001; Yaremcio, 2001¸ Thiex & German, 2004). The classes are to be treated as guidance levels for human and livestock consumption.

6. Results

The total of 2001 site records finally deemed usable for map production cover the period 1970 to 2003 but with emphasis on the years 1990 to 2003 (Volume II). Surely, because of the long time period over which the mapped data stretch, results given are of indicative rather than absolute nature. Since chemical constituents in groundwater may change swiftly both in space and time, especially in the case of a pollutant such as nitrate, groundwater quality maps do not provide an image of reality that lasts for an indefinitely long period of time. But they certainly do highlight areas and spots where problems existed in the past, where problems may still exist or may yet again develop in future. The attached groundwater quality maps are thus designed to help policy makers and organizations that are involved in the administration and development of groundwater resources to find general information and to encourage them to ascertain facts. - 15 -

6.1. Groundwater nitrate hotspots

The map on groundwater nitrate hotspots (Appendix I) highlights 10 areas and/or spots where highly elevated groundwater nitrate concentrations (440 to 1000 mg/L) were present at a certain point in time. Seven of these areas are emphasised on the map in the form of separate inlays.

Commencing from East to West, the first hotspot that catches the eye is the intensively farmed area around Sherwood Ranch on the border to South Africa. Another nitrate hotspot within the Tuli block farms is Baine’s Drift further to the NE, in the wider vicinity of which there are also hotspots of lesser magnitude (180-440 mg/L), as is the case at Sherwood Ranch. Although it is mere speculation, what springs to mind is that farming was the likely source of the observed excessive nitrate concentrations in the affected boreholes.

Not surprisingly, some boreholes in the more densely populated settlements of Palapye and Serowe also stick out as nitrate hotspots. Given the experience made in similar built-up areas in eastern Botswana one is inclined to attribute most of these hotspots to sanitation (Lewis et al., 1980; Lagerstedt et al., 1994; Jacks et al., 1999; Mafa, 2003; Staudt, 2003).

A conspicuous assemblage of hotspots is visible in the diamond-mining triangle Letlhakane - Orapa -Damtshaa. In the immediate vicinity of the mines, ammonium nitrate -based explosives may play a certain role as may sanitation and landfills (Mokokwe, 1999; Matthes, 2002; Keipeile, 2004). These potential sources are however most unlikely to have caused singular hotspots with outstandingly high nitrate concentrations exceeding 440 mg/L. Similarly, the few hotspots south of Letlhakane with concentration between 180 to 440 mg/L must have been due to causes other than mining, sanitation, or landfills. The same applies to the outstanding hotspots west of Orapa and east of Rakops.

In the absence of industrial and urban activities, cattle posts are assumed to play a key role when it comes to singular boreholes boasting exceptionally high nitrate concentrations, especially after particularly high rainfall (see, e.g., Heaton, 1984). Surely, heavily loaded point sources such as cattle posts are the most likely cause for such phenomena, possibly enhanced in places by preferential groundwater flow.

In this context it is interesting to note that recent research concludes that present cattle farming does not yet affect current nitrate concentrations in the Ntane sandstone aquifer in the area between Serowe and Orapa, in spite of the high soil nitrogen loads observed at cattle posts (Schw iede et al., 2004; Stadler et al., 2004a; Stadler et al., 2004b). The results of these studies point to only a slow progression of soil nitrates towards the groundwater, due to the observed long residence times (solute travel times) in the unsaturated zone. All the same, their results still imply a soil source ascribable to natural accumulation processes in the soil.

Maximum concentrations of up to 250 mg/L encountered during sampling for the above study, which took place between June 2002 and May 2004, were way below the levels documented for a series of boreholes that were available for this report. Amongst them were 28 boreholes that featured between 300 to 945 mg of nitrate per litre of water at one point in time. In one truly remarkable case, a borehole in Damtshaa (borehole no. 1694) that was sampled by the Environmental Geology Division after the heavy rains in the year 2000,

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revealed a staggering nitrate concentration of 2000 mg/L2. Several goats that drank water spilled from this borehole during the course of groundwater sampling died.

The months February and early March 2000 had experienced exceptionally high rainfall. Time and again, overland flow was rampant all over the Kalahari sandveld and land depressions such as pans were filled in no time. In these depressions water did not reside until it had totally evaporated over subsequent weeks or months but instead visible drops in water levels were observed within days. It is therefore assumed that immediate downpour recharge does occur in depressions such as pans. Such rare recharge (flushing) events in the wake of torrential rainfall have also been reported from dryland environments in Australia (Barnes et al., 1992).

For a few boreholes for which data was available for longer periods of time, time series were done. Although the nitrate concentrations at these particular sites were not awfully high, they nevertheless underlined that nitrate concentrations in groundwater may be highly variable both within a single rainfall season and across years.

An illustration of significant variability within a single rainfall season came from Kgagodi, where nitrate levels in 1998 shot up very briefly in early March (Fig. 5). The Kgagodi example also highlights how crucial the date of sampling is. In fact, in this particular case it appears that hit or miss was a matter of days only.

50 40 30 20

NO3 mg/L 10 0

29.01.1998 11.03.1998 20.03.1998 03.04.1998 25.04.1998 19.11.1998

Figure 5: Fluctuation of nitrate concentrations in Kgagodi in 1998

A case in point for annual fluctuation came from Mathathane (Fig. 6). In some ye ars, nitrate concentrations were close to or even above the maximum allowable limit of 45 mg/L (BOS, 2000), while in most other years they were low to non-existent.

An example for a virtually unaltered level of nitrate in groundwater came from the police station in Martin’s Drift (Fig. 7). There, nitrate concentrations appear to remain fairly stable after an initial rise subsequent to the year 1987.

An instance that may point to the exceptional situation in the year 2000 came from Machaneng (Fig. 8). While for many years nitrate concentrations appear to have been low and stable, they all of a sudden showed a marked rise in March 2000. Immediately thereafter, in May 2000, they had fallen back to just above the previously typical level.

2 Since the nitrate concentration measured for this borehole was a real exception, no new class was added to the legend of the map on groundwater nitrate hotspots but the site mapped as part of the 880-1000 mg/L category. - 17 -

80 60 40 20 NO3 mg/L 0

09.10.197912.08.198115.08.198116.08.198810.09.198803.09.198929.09.199715.07.199807.08.200129.01.2002

Figure 6: Development of nitrate concentrations in Mathathane between 1979 and 2002

40 30 20 10 NO3 mg/L 0

08.09.1987 29.11.1993 04.06.1997 07.07.2000 04.09.2000 16.01.2003

Figure 7: Nitrate concentrations at police station in Martin’s Drift

80 60 40 20 NO3 mg/L 0

20.09.197825.09.197901.02.199009.03.199002.03.199308.08.199530.06.199806.07.199809.07.199801.03.200007.03.200002.05.2000

Figure 8: Nitrate concentrations at Machaneng

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6.2. Total dissolved solids in groundwater

The map of total dissolved solids in groundwater (Appendix II) indicates yet again areas where either human factors may have contributed to high TDS levels, or else, where natural sources seem to prevail.

Anthropogenic pollution may have been the dominant factor that gave rise to the observed few high TDS concentrations in boreholes located along the major population axis in the East, from Dibete in the SW to Tutume in the NE via Mahalapye, Palapye, and Serule. A number of boreholes along this line featured highly saline water (10000 to 44999 mg/L) that is considered unsatisfactory for all classes of livestock. The observed concentrations may have been caused by human factors such as sewage, landfills, and livestock production.

The highest occurrence and concentrations of TDS were found in a more or less crescent- shaped region around the western fringe of Ntwetwe pan from Letlhakane -Orapa to east of Gweta via Rakops and Motopi. Clearly, these are the natural discharge areas for regional groundwater flow both from the SE (Serowe) and the NW (Okavango). Obviously, over geological time the Makgadikgadi pan complex has been a natural salt trap. The horizontal salinity gradient from the Ntane sandstone escarpment near Serowe to the discharge area west of Orapa makes this visible. It appears safe to assume that the same gradient exists from the Okavango delta region down the river Boteti.

The conspicuously high TDS levels in the area between Orapa and Rakops, and again around Motopi, may to a considerable amount also stem from wind-blown salts from the evaporative deposits of the Makgadikgadi pan complex. According to Wood et al. (2004) over three million metric tons of chloride, sodium, and bicarbonate are transported each year to adjacent land west of the pan complex. Low river gradients and very limited rainfall prevent thorough flushing of the accumulated salts.

Another conspicuous area of hyper-saline groundwater (45000 to 94999 mg/L) is Maitengwe, located NE of Nata, on the border to Zimbabwe. The extremely high salinity groundwaters in this area coincide with a structural geologic feature, namely the Bushman lineament, which turns the previously sloping freshwater aquifer abruptly into a flat and much deeper saline aquifer (Karen, 2005).

6.3. Selected groundwater salinity indicators

As was to be expected, the composite map of selected groundwater salinity indicators (Appendix III) supports the TDS picture, although the elevated sites along the eastern population axis are not as eye-catching on this map at first sight. The reason for this is that far fewer data were available for electrical conductivity. Hence, the indicator that depicts total salinity is underrepresented. However, a closer look at the individual indicators chloride, sulphate, and sodium points to the same few elevated sites in the east of the Central District.

The horizontal salinity gradient along the general flow path from the Serowe escarpment towards Ntwetwe pan is again visible. The highest chloride, sodium, and sulphate concentrations were found west of Orapa, that is farthest from the recharge area. The same applies to electrical conductivity. Similarly, the highly mineralized groundwaters in the western crescent around Ntwetwe Pan and also in the Maitengwe area, again stand out.

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A linear regression analysis of sodium versus chloride concentrations was carried out for only those boreholes, which had results for both indicators and where the data were greater than zero. These conditions applied to 1396 sites. The analysis produced a correlation coefficient of 0.96. This linear relation suggests that halite (NaCl) dissolution was the mineral source of both sodium and chloride for the vast majority of groundwaters at the 1396 sites (Figure 9). Because sodium and chloride ions enter solution in equal quantity during the dissolution of halite (Hem, 1985).

70000 60000 50000 40000 30000 20000

Sodium (mg/L) 10000 0 0 10000 20000 30000 40000 50000 60000 70000 80000 90000

Chloride (mg/L)

Figure 9: Chloride versus sodium concentrations at 1396 sites in the Central District

7. Discussion and conclusions

Groundwater quality mapping in the Central District confirmed that there is reason for concern because elevated nitrate and salinity levels render groundwater unsuitable for human and livestock consumption in many places. With regards to nitrate contamination the hazard in rural areas may be more of a sporadic nature, though of a frighteningly high magnitude at times.

The latter underlines that nitrates are at least an annual sampling requirement for all drinking water supply boreholes and wellfields. Ideally, sampling should be done around the same time of the year, preferably just after the rainy season. If time and resources allow, an extra sampling should be carried out just before the rains commence so as to obtain a dry and rainy season comparison.

The study also highlighted that sampling must follow guidelines as were developed for the Environmental Geology Division (Appendix IV). Meticulous record keeping that includes detailed geographical co-ordinates is of equal importance. Neither appeared to have been of high standard in many instances in the past. In addition, groundwater quality monitoring has hitherto suffered from lack of consistency, which makes reporting on the state and trends in groundwater quality difficult.

The data analysed for this report and their graphing and mapping revealed that processes of nitrate generation and its subsequent transport into groundwater are, for the most part, characterised by high spatial and temporal variability. Also, the patchy distribution of

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boreholes that constituted nitrate hotspots suggests that the nitrate was derived from point sources.

The observed variability was certainly also influenced by complex hydrogeological settings that affect the movement of groundwater to an important degree (cf. Matthes, 2002; Stadler et al., 2004a; Stadler et al., 2004b). In many areas, surface and groundwater interactions, and recharge and discharge relationships, are likely to be strongly modified by structural features such as intrusions of dolerite dykes and faulting.

The complex hydrogeological settings made it difficult to generalize about district-wide groundwater quality. As a result, mapped groundwater quality data indicate only the water quality at a specific location and depth in an aquifer. One must also keep in mind that concentrations may change swiftly and abruptly with sudden groundwater recharge, massive groundwater abstraction (groundwater mining), and severe point pollution.

The picture appeared to have been further complic ated by dispersive mixing of groundwaters and some vertical nitrate stratification in the saturated zone (Stadler et al., 2004a; Stadler et al., 2004b). Given the physics of groundwater recharge, nitrates are expected to be found mostly in boreholes that are sunk into shallow water table s, and in boreholes that are finished at shallow depths within aquifers, because most nitrate sources are at the land surface and also because nitrate is associated with dissolved oxygen (DO) in the upper sections of aquifers (Moore & Fenelon, 1996). Unless there is mixing of the aquifer, deep boreholes tend to be anoxic and hence nitrate deficient because when oxygen is depleted, denitrifying microbes in the presence of reduced reactive organic carbon3 take away oxygen from the nitrate ion and eventually turn it into gaseous nitrogen. Depending on the pH, nitrate is one of the strongest oxidizers after oxygen.

When groundwater is pumped from boreholes with long screens, stratification is integrated and a mixed sample is obtained, which is less variable (MAF, 2000). Ideally, borehole details (e.g. screen length), abstraction method (e.g. multi-level sampling), and abstraction depth ought to be taken into account when interpreting data on nitrate concentrations in groundwater. The same applies to the employed salinity indicators.

Clearly, groundwater research and monitoring must be ongoing and long-term so as to ensure a high degree of certainty in the accuracy of findings. This is of particular relevance where results are influenced by nonlinear climatic factors, nitrogen inputs from various natural and human sources, and complex hydrogeological settings, all of which apply to the Central District of Botswana.

3 Organic carbon is the major control of redox reactions. Oxidation of organic carbon essentially generates electrons, i.e. electron donor. - 21 -

8. References

ADB (1995): Country Environmental Profile Botswana . Environment and Social Policy Working Paper Series, The African Development Bank Group, African Development Fund, September 1995, 55 p.

Appelo, C.A.J., and D. Postma (1999): Geochemistry, groundwater and pollution. A.A. Balkema, Rotterdam, The Netherlands, 536 pp.

Aranibar, J.N., Anderson, I.C., Ringrose, S., and S.A. Macko (2003): Importance of nitrogen fixation in soil crusts of southern African arid ecosystems: acetylene reduction and stable isotope studies. Journal of Arid Environments 54: 345-358.

Ashton, P.J., Love, D., Mahachi, H., and P.H.G.M. Dirks (2001): An overview of the impact of mining and mineral processing operations on water resources and water quality in the Zambezi, Limpopo and Olifants catchments in Southern Africa. Contract Report to the Mining, Minerals and Sustainable Development (SOUTHERN AFRICA) Project, by CSIR- Environmentek, Pretoria, South Africa and Geology Department, University of Zimbabwe, Harare, Zimbabwe. Report No. ENV-P -C 2001-042. xvi + 336 pp.

Barnes C.J., Jacobson G., and G.D. Smith (1992): The origin of high-nitrate groundwaters in the Australian arid-zone. Journal of Hydrology 137: 181-197.

Bauder, J. (1998): When is water good enough for livestock? Montana State University, Extension Service (http://www.montana.edu/wwwpb/ag/baudr146.html).

BNA (2001): Botswana National Atlas. The Department of Surveys and Mapping, Gaborone, Botswana.

BOS (2000): Water quality – Drinking water – Specification. BOS 32, Botswana Bureau of Standards, Gaborone, Botswana.

Coakley, G.J. (2001): The Mineral Industry of Botswana in 2000. 4 p. (http://minerals.usgs.gov/minerals/pubs/country/2000/bcmyb00.pdf).

Coakley, G.J. (2002): The Mineral Industry of Botswana in 2001. 4 p. (http://minerals.usgs.gov/minerals/pubs/country/2001/bcmyb01.pdf).

Darkoh, M.B.K. (1997): Desertification in Botswana. Rala Report No. 200, pp. 61-74.

DEH, 2003: Groundwater Salinity/Baseflow Salinity. Department of the Environment and Heritage (DEH), Australian Government (http://www.deh.gov.au/nrm/monitoring/indicators/ salinity/pubs/groundwater.pdf)

Evans, R.D., and J. Belnap (1999): Long–term consequences of disturbance on nitrogen dynamics in an arid grassland ecosystem. Ecology 80: 150-160.

Edmunds , W.M., and C.B. Gaye (1997): Naturally high nitrate concentrations in groundwaters from the Sahel. - Journal of Environmental Quality 26 :1231-1239.

Hawkes, C.V. (2003): Nitrogen cycling mediated by biological soil crusts and arbuscular mycorrhizal fungi. Ecology, 84(6): 1553–1562. - 22 -

Heaton, T.H.E, Talma, A.S, and J.C. Vogel (1983): Origin and history of nitrate in confined groundwater in the Western Kalahari. Journal of Hydrology 62: 243-262.

Heaton, T.H.E. (1984): Sources of the nitrate in phreatic groundwater in the western Kalahari. Journal of Hydrology 67: 249-295.

Heaton, T.H.E. (1985): Isotopic and chemical aspects of nitrate in the groundwater of the Springbok Flats. Water SA 11(4): 199-208.

Hem, J.D. (1985): Study and interpretation of the chemic al characteristics of natural water. U.S. Geological Survey Water-Supply Paper 2254, 3rd Ed., 264 pp., Washington, D.C.

Hitchon, B., Perkins, E.H., and W.D. Gunter (1999): Introduction to ground water geochemistry. Geoscience Publishing Ltd., Sherwood Park, Alberta, Canada, 310 p.

Holloway, J.M., and R.A. Dahlgren (2002): Nitrogen in rock: Occurrences and biogeochemical implications.Global Biogeochemical Cycles 16(4): 65/1-65/17.

Jacks, G., Sefe, F., Hammar, M. & Letsamao, P. (1999): Tentative nitrogen budget for pit latrines, Eastern Botswana, Environmental Geology, 38(3): 199-203.

Jaikaran, S. (1993): Water analysis interpretation. Alberta Agriculture, Food and Rural Development, Agdex 400/716-2 (http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/ agdex718).

Johnston, R. (1997): Introduction to microbiotic crusts. United States Department of Agriculture, Natural Resources Conservation Service, Soil Quality Institute, Grazing Lands Technology Institute, 16 p.

Karen, M. (2005): The hydrogeology of the Ntane sandstone, Botswana. In: Vogel, H. (Ed.): Environmental Geology in Semi-Arid Environments. Proceedings of a workshop held at the Syringa Lodge, Selebi-Phikwe, 11-12 November 2004, Dept. of Geological Survey, Lobatse, Botswana (in preparation).

Keipeile, K. (2004): Environmental hydrogeology of Letlhakane. Report by the Environmental Geology Division, Dept. of Geological Survey (DGS), 52 p., Lobatse, Botswana.

Lagerstedt, E., Jacks, G. & Sefe, F. (1994): Nitrate in groundwater and N circulation in Eastern Botswana. Environmental Geology 23: 60-64.

Lewis, W.J., Farr, J.L. & Foster, S.S.D. (1980): The pollution hazard to village water supplies in eastern Botswana. Proc. Instn, Civ.Engrs 2( 69): 281-293.

MAF (2000). Implications of groundwater nitrate standards for agricultural management. Ministry of Agriculture and Forestry, Technical Paper 2000/15, 177 p., New Zealand.

Mafa, B. (2003): Environmental Hydrogeology of Francistown. Effects of Mining and Urban Expansion on Groundwater Quality. Report by the Environmental Geology Division, 24 p. plus Appendices, Dept. of Geological Survey (DGS), Lobatse, Botswana.

- 23 -

Matthes, L. (2002): Environmental hydrogeology of Orapa. Report by the Environmental Geology Division, Dept. of Geological Survey (DGS), 67 p., Lobatse, Botswana.

May, D.G. (1985): A Geography of Botswana. Macmillan Boleswa Publishers, Manzini, Swaziland.

Mokokwe, K. (1999): Occurrence of groundwater with high nitrate content, Orapa wellfields. Inception report, Dept. of Geological Survey (DGS), Lobatse, Botswana (unpublished).

Mokokwe, K., and A. Wolff (2001): Piezometry and Hydrochemistry. Origin of elevated nitrate in the Ntane sandstone aquifer between Serowe and Orapa. Draft digital map. Environmental Geology Division, Dept. of Geological Survey (DGS), Lobatse, Botswana.

Moore, R.C., and J.M. Fenelon (1996): Occurrence of nitrate in ground water in the White River Basin, Indiana, 1994-95. U.S. Geological Survey Fact Sheet 110-96, 4 p.

Schimel, D.S., Braswell, B.H., and W.J. Parton (1997): Equilibration of the terrestrial water, nitrogen, and carbon cycles. Proc. Natl. Acad. Sci. 94: 8280–8283.

Schwiede, M., Duijnisveld, W., and J. Böttcher (2004): Nitrate in soils and the vadose zone above the Ntane Sandstone aquifer – Sources, balance and depth distribution. In: Proceedings of the Conference “Environmental Geology in Semi-Arid Regions”, Selebi-Phikwe, 11-12 Novmeber 2004, Dept. of Geological Survey (DGS), Botswana.

Setloboko, T.S. (2003): Nitrate concentration in groundwater in correlation to land use. Boteti Area, Central Botswana. MSc thesis, Institute for Geoscience, Center for Applied Geoscience, Eberhard Karls Universität, Tübingen, Germany (unpublished).

Solomon, M.H. (2000): Growth and diversification in mineral economies. Planning and incentives for diversification. 23 p., UNCTAD regional workshop, Cape Town, South Africa, 7-9 November 2000 (http://www.natural-resources.org/minerals/CD/docs/unctad/ solomon. pdf).

Stadler, S., von Hoyer, M., Duijnisveld, W.H.M., Himmelsbach, T., Schwiede, M., Böttcher, J., H. and H. Hötzl (2004a): Investigation of natural enrichment processes of nitrate in soil and groundwate r of semi-arid regions: case-study Botswana. In: Stephenson, D., Shemang, E.M. and T.R. Choaka (Eds.): Water Resources of Arid Areas. Proceedings of the International Conference on Water Resources of Arid and Semi Arid Regions of Africa (WRASRA), 3-6 Augus t 2004, Gaborone, Botswana, pp. 379-388.

Stadler, S., von Hoyer, M., and T. Himmelsbach (2004b): Natural nitrate in the Ntane sandstone aquifer: Origin, fate and impacts on groundwater management. In: Proceedings of the Conference “Environmental Geology in Semi-Arid Regions”, Selebi-Phikwe, 11-12 Novmeber 2004, Dept. of Geological Survey (DGS), Botswana.

Staudt, M. (2003): Environmental Hydrogeology of Ramotswa. Report by the Environmental Geology Division, 36 p. plus Appendices, Dept. of Geological Survey (DGS), Lobatse, Botswana.

Stoltenow, Ch., and G. Lardy (1998): Nitrate Poisoning of Livestock. North Dakota State University, NDSU Extension Service (http://www.ext.nodak.edu/extpubs/ansci/ livestoc/v8339htm).

- 24 -

Swap, R.J., Aranibar, J.N., Dowty, P.R., Gilhooly, W.P., and S.A. Macko (2004): Natural 13 15 abundance of C and N in C3 and C4 vegetation of southern Africa: patterns and implications. Global Change Biology 10(3): 350-358.

Thangarajan, M., L inn, F., Uhl, V., Bakaya, T., and G. Gabaake (1999): Modelling an inland Delta aquifer system to evolve pre-development management schemes: a case study in Upper Thamalakane River valley, Botswana, southern Africa. Environmental Geology 38 (4): 285 – 295.

Thiex, N., and D. German (2004): Interpretation of water analysis for livestock suitability. College of Agriculture & Biological Sciences, South Dakota State University, USDA, Cooperative Extension Service, ExEx 2042, Animal and Range Sciences (http://agbiopubs.sdstate.edu/articles/ExEx2042.pdf)

Thomas, D.S.G., and P.A. Shaw (1991): The Kalahari environment. Cambridge Univ. Press, 284 p.

Tredoux; G. (2004): Nitrate and associated hazard quantification and strategies for protecting rural water supplies. Report to the Water Research Commission, No. 1058/1/04, 75 p. plus appendices, Stellenbosch, Republic of South Africa.

Tredoux, G., Clarke, S., and L. Cavé (2004): The feasibility of in situ groundwater remediation as robust low-cost water treatment option. Report to the Water Research Commission, No. 1325/1/04, 59 p. plus appendices, Stellenbosch, Republic of South Africa.

Undersander, D., Combs, D., Howard, T., Shaver, R., Siemens, M., and D. Thomas (2001): Nitrate Poisoning in Cattle, Sheep and Goats. University of Wisconsin, Cooperative Extension (http://www.uwex.edu/ces/forage/pubs/nitrate.htm).

Vogel, H. (2002): The soil nitrogen cycle. Report by the Environmental Geology Division, Dept. of Geological Survey (DGS), 25 pp., Lobatse, Botswana.

Wagner, D. (1997): The influence of ant nests on Acacia seed production, herbivory and soil nutrients. Journal of Ecology 85: 83-93.

Wagner, D., Brown, M.J.F., and D.M. Gordon (1997): Harvester ant nests, soil biota and soil chemistry. Oecologia 11: 232-236.

Wagner, D., Jones, J.B., and D.M. Gordon (2004): Development of harvester ant colonies alters soil chemistry. Soil Biology & Biochemistry 36: 797-804.

Wagner, D., and J.B. Jones (2004): The contribution of harvester ant nests, Pogonomyrmex rugosus (Hymenoptera, Formicidae), to soil nutrient stocks and microbial biomass in the Mojave Desert. Environmental Entomology: (accepted for publication).

Walvoord, M.A., Phillips, F.M., Stonestrom, D.A., Evans, R.D., Hartsough, P.C., Newman, B.D., and R.G. Striegl (2003): A reservoir of nitrate beneath desert soils. Science 302: 1021- 1024.

White, W.M. (2003): Geochemistry. An on-line textbook, Cornell Univ., U.S.A. (http://www.geo.cornell.edu/geology/classes/geo455/Chapters.HTML).

- 25 -

WHO (1993): Guidelines for drinking-water quality, 2nd ed. Vol. 1. Recommendations. World Health Organization, Geneva, Switzerland.

Wood, W.W., Eckardt, F., Kraemer, T.T. and K. Eng (2004): Quantitative eolian transport of evaporate salts from the Makgadikgadi Depression (Ntwetwe and Sua Pans) in northeastern Botswana. Implicatio ns for regional ground-water quality. In: Sabka Ecosystems Volume 3, Africa. Barth, H.-J. and B. Böer (Eds.), Kluwer (in press).

Wormald, R.J., Eckardt, F.D., and J. and S. Vearncombe (2003): Spatial distribution analysis of pans in Botswana: The importance of structural control. South African Journal of Geology 106: 287-290.

Yaremcio, B. (2001): Nitrate Poisoning and Feeding Nitrate Feeds to Livestock. Alberta Agriculture, Food and Rural Development, Agdex 400/60-1 (http://www.agric.gov.ab.ca/ agdex/ 400/0006001.html).

Zublena, J.P., Cook, M. G. and M. B. St. Clair (1993): Pollutants in groundwater: Health effects. North Carolina Cooperative Extension Service, Publication AG-439-14 (http://www.soil.ncsu.edu/publications/Soilfacts/AG-439-14/).

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APPENDICES

- 27 - PR° PS° PT° PU° PV° PW° PHHHHH QHHHHH RHHHHH SHHHHH THHHHH UHHHHH

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Appendiix IV: Guidelines for groundwater sampling

In order to obtain accurate results from groundwater quality studies, some precautions must be taken in collecting the sample. Many testing laboratories insist on the use of certain sample bottles or containers and supply instructions for collecting, preserving and handling samples. To get specific instructions one must therefore contact the laboratory that will be running the tests prior to sampling.

Please also note that some pollutants may be more present during certain times of the year. For example, nitrates are often most likely to be found during wet weather. Hence, in order to adequately assess the year-round safety of drinking water, samples ought to be collected when contaminants are most likely to be present.

The following general sampling guidelines were developed for the Environmental Geology Division at the Botswana Department of Geology:

(1) In order to achieve data comparability it is necessary and essential that groundwater samples be collected under the same conditions, that is at the same time, or else, over a short period of time (possibly days).

(2) Certain groundwater characteristics must be recorded in the field. These include hydrogen ion concentration (pH), oxidation-reduction (redox) potential (Redox in mV, has to be re- calculated to EH), dissolved oxygen (O2 in mg/L and % saturation), temperature (°C), and specific electrical conductivity (EC in µS/cm at 25°C)4.

- 5 Bicarbonate (HCO3 ) and carbon dioxide (CO2) contents are also determined in the field but 6 - by titration (see, for example, www.merck.de). Alkalinity (HCO3 -concentration) is ascertained by drop-wis e titration with a strong acid (e.g. HCl, H2SO4) to an endpoint signaled by a change in colour of an added indicator (e.g. Phenolphthalein, Bromcresol Green-Methyl Red). Knowing the volume of the water sample (V), the volume of the acid solution required to reach the endpoint (V 0) and the normality of the acid (Nacid), one can calculate the alkalinity. In the case of CO2, titration is with a base (NaOH), again to an endpoint signaled by a change in colour of the phenolphthalein indicator.

Titration should be carried out in the shade and against a white background. In order to verify the result, titration may be repeated once or twice and a mean value taken.

4 In the past, the project used single meters for measuring these field parameters but lately acquired a multi- parameter instrument (www.WTW.com). 5 – – At low pH, CO2 predominates. As the pH increases, the HCO3 concentration increases. Eventually HCO3 passes up CO2, and bicarbonate becomes the predominant carbonate species. At even higher pH, carbonate 2- (CO3 ) eventually predominates. The carbon dioxide-bicarbonate crossover, where carbon dioxide starts decreasing, lies around pH 6.4, while the bicarbonate-carbonate crossover, when bicarbonate starts decreasing, lies around pH 10.3. The carbon dioxide-carbonate crossover point, when carbon dioxide activity falls sharply below carbonate activity lies around pH 8.2. 6 Titration is based on the fact that acids and bases do neutralize each other. The most important tool with titration is a buret or flask. Select the appropriate sample volume and refer to the titration instructions specific to the method in use. Add the indicator to the sample and titrate (by adding incremental amounts - drop by drop - of the acid used) until the added indicator indicates the endpoint. The concentration of the sample can then be determined through calculation or by means of tables. - 31 -

All field parameters must be recorded in a consistent manner and entered into a field data sheet. General information such as coordinates, depth of borehole filter, geology, and vegetation also ought to be recorded.

(3) Prior to pumping, the static water level in the wells, boreholes or piezometers must be measured by means of an electric dipper and the sampling depth recorded.

Please note that pumping should be at a rate that makes a small drawdown possible. The maximum drawdown must be measured and recorded. Actual sampling should be done at a constant pumping rate.

(4) After the water level has been recorded, all stagnant water must be removed from the borehole. Generally, this is achieved by pumping out a volume of water equal to three times the bore casing.

Purging all stagnant water ensures that only groundwater from the in situ aquifer is collected, that is groundwater representative of the geologic material under investigation. Employing our mobile Grundfos MP1 submersible pump (www.grundfos.com) this may require 1 to 2 hours of pumping. In order to collect representative groundwater samples from pump- equipped production boreholes, samples should be taken from the tap only after the pump had been in operation for a while.

Once the levels of EC and pH, measured permanently by electrode in a flow through cell (in order to prevent air admission), remain constant for at least 5 minutes the sample may be taken (because steadied EC and pH levels indicate that groundwater quality has stabilized).

The EC and pH meters should be calibrated at least once daily but preferably before every measurement. The flow rate from the pump also has to be determined by means of a bucket and a stopwatch and a written note of it must be made into the field data sheet (L/min).

(5) All sample bottles, syringes and filters must be “conditioned” with the groundwater under investigation, that is they must be thoroughly rinsed twice with water from the borehole before the final sample is taken. The water used to condition the sampling tools and bottles must be discarded.

(6) Since the analyses of cations and anions require different conservation methods, all groundwater samples must at least be taken in duplicate. Quite often a 100 ml bottle is used for the cation and trace element analysis, and a 250 ml bottle for the anion analysis.

(a) Please note that only transparent bottles made from polyethylene (PE) may be used so as to see whether the sample contains any suspended material. Coloured bottles obscure suspended matter. They are to be avoided by all means since they often conta in metals. The metals may enter into the water, in particular in the case of acidified samples. A third glass bottle (alternatively a PFA bottle) is therefore often introduced for the analysis of trace elements.

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(b) Ideally, the bottles also ought to feature a wide bottleneck so as to be able to insert an electrode. In order to determine any possible influence of the bottle on the sample, please submit 1 extra bottle filled with distilled water (aqua dest).

(c) The samples meant for cation (and possibly t race element) analysis need to be acidified so as to ensure a low pH value. This helps prevent precipitation and also limits sorption to the bottle walls before the samples are analysed in the laboratory (sample conservation). Preferably HNO3 is used at a concentration of 1 Vol.-%, which means that 1 ml of concentrated HNO3 is added into each and every 100 ml bottle. Actual acidification is done after the sample bottle has been filled approximately halfway with water. After acidification the bottle is fille d to the top edge so that in case of spillage no volume of acid will be lost.

Along with the acidified samples at least 1, better 2, 50 ml samples of the acid used ought to be submitted (for safety reasons dilute 1:1 with distilled water).

(d) Prior to acidification, groundwater samples have to be filtered to remove suspended material, which may otherwise dissolve. The standard procedure is to fill the water into a 50 ml syringe – after the syringe has been conditioned twice and the water used to conditio n has been discarded - and then push it into the sample bottle through 0.45 µm membrane filters. The first 10 ml of the filtrate also have to be discarded. In the presence of colloidal Fe - and Al-oxyhydroxides, the use of 0.1 µm filters may be the better option.

(e) It is of prime importance that the sample bottles are filled to the rim so as to avoid air being trapped in the bottle (the plastic bottles may be gently squeezed upon closing the lid).

(f) The 250 ml samples taken for anion analysis must neither be acidified nor filtered. If available, they may be treated with a bacteria inhibitor so as to prevent bacteria from altering the concentration of nitrate and ammonia in the sample prior to the laboratory analysis. The addition of a bacteria inhibitor - if available - is advisable for the analysis of the nitrogen - - compounds NO3 and NO2 .

(7) If the samples are to be analysed at the BGR laboratory in Hannover, Germany, and if you can obtain clear groundwater samples, then the following set of samples has to be submitted:

(a) 500 ml PE bottle for anion analysis. They must neither be acidified nor filtered.

(b) 100 ml PE bottle for cation analysis. They must be filtered (0.45 µm membrane filter) and then acidified (1 ml concentrated HNO3 per each 100 ml sample).

(c) 125 ml narrow-mouth Nalgene PFA bottles for trace element analysis. Again, they must first be filtered through 0.45 µm membrane filters and then acidified with 1.25 ml concentrated HNO3 per each 125 ml sample.

(d) If, and only if the total trace element concentrations are required then, again, 125 ml PFA bottles are used. These samples, however, must not be filtered but only acidified with 1.25 ml conc. HNO3 per each 125 ml sample.

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With regards to the analysis of trace elements, the quality of the acid may constitute a problem. In order to determine any possible influence, it is advisable to submit the followings extras:

1 sample of the acid used in 125 ml PFA bottle. This sample ought to be diluted down to a non-smoking concentration (for example, 1:4 concentration).

1 sample of the distilled water used, also in a 125 ml PFA bottle.

(8) Once the samples have been taken, the equipment including that used for titration must be rinsed (decontaminated) thoroughly with distilled water so as to avoid cross contamination at the next sampling site.

(9) All filled sample bottles must be stored in cool conditions and protected against direct sunlight exposure. Ideally, all samples should be analysed as soon as possible so as to ensure accurate results. If the samples cannot be transported immediately then they need to be refrigerated (do not freeze). While on transport, they also ought to be stored in a cooler box or a mobile 12V refrigerator.

PROJECT MANAGER

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