BIOACCUMULATION OF METALS IN SELECTED FISH SPECIES AND THE EFFECT OF PH ON ALUMINIUM TOXICITY IN A CICHLID OREOCHROMIS MOSSAMBICUS
BY LIZET COETZEE
THESIS
SUBMITTED IN FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE MASTER OF SCIENCES
IN ZOOLOGY
IN THE
FACULTY OF NATURAL SCIENCES
AT THE RAND AFRIKAANS UNIVERSITY
SUPERVISOR: PROF H.H. DU PREEZ CO-SUPERVISOR: PROF J.H.J. VAN VUREN
MAY 1996 - ACKNOWLEDGEMENTS -
Special thanks to:
My Lord for the wisdom, strength and insight He gave me:
" By wisdom the Lord laid the earth's foundation; By understanding He set the heavens in place" "Wisdom is supreme, therefore get wisdom, though it cost all you have; get understanding" Proverbs 3:19; 4:7
My supervisor, Prof H.H. du Preez and co-supervisor, Prof J.H.J. van Vuren, for their support, motivation and guidance throughout the project
Prof J.H. Swanepoel, the head of Department Zoology, for the use of the facilities and the opportunity to perform this study
My parents for their patience, love and financial support during my studies
My husband for his love, support and motivation; without him it wouldn't have been possible
The Rand Afrikaans University, Water Research Board and the Foundation for Research Development for their financial support
The Institute for Water Quality Studies, Department of Water Affairs and Forestry for the chemical analysis of the water samples
Dirk Erlank Gabriel Motlhabane, Solomon Kwapa (Switch) and Solomon Tshabala (Sony) for their assistance with the experimental systems and my work in the aquarium
Naas and Reinette Ferreira for the use of their computer and all their support
Irma Naude for linguistically attending to my thesis
Gail Nussey for all her support and advise -ABSTRACT-
The Upper catchment of the Olifants River, from its origin near Bethal, to its confluence with the Wilge River, north of Witbank, as well as it tributaries, are being subjected to increasing afforestation, mining, power generation, irrigation, domestic and industrial activities. These activities have a profound effect on the water quality and the major point sources of pollution in this area include mines, industries and very importantly, combined sewage purification works, located alongside the river, which, in addition to oxidizable material contains detergents, nutrients, and metals. It was therefore necessary to determine the extent to which these activities affect the water quality of the system. The impact of these activities was therefore addressed by a Water Research Commision Project namely "Lethal and sublethal effects of metals on the physiology of fish" of which the present study investigated effects at two localities, namely in the Olifants River (locality OR1) before its confluence with the Klein Olifants River and a locality in the Klein Olifants River (locality KOR1). Apart from the field study, toxicity tests were also performed in a laboratory, in order to determine the effects of low pH and elevated aluminium concentrations on the haematology, osmoregulation and carbohydrate metabolism of the Mozambique Tilapia, Oreochromis mossambicus as the acidification of soil systems may cause the transfer of aluminium into aqueous solutions, where it may be present in different forms. During the field study, the chemical and physical characteristics of the river water were evaluated, with special attention to the concentrations of certain metals (manganese, copper, chromium, lead, nickel, zinc, iron and aluminium) in the water and sediment, as well as in fish, which are known to accumulate the elements supra and are therefore valuable as indicators of these pollutants.
ii The two fish species used for the investigations were the African sharptooth catfish, Clarias gariepinus and the moggel, Labeo umbratus. Four tissue types were dissected, namely the muscle, liver, skin and gill tissues. The metal concentrations in these organs/tissues, as well as in the water and sediment, were determined in a laboratory with an atomic absorption spectrophotometer. Statistical analyses were performed on the results obtained from this study and the order and extent of bioaccumulation of these metals in the water and sediment were determined, as well as in the fish organs/tissues. Its dependence on the size, sex and species of the fish and the localities and seasons were investigated.
The selected water quality variables were mostly well within the guideline limits proposed for the protection of aquatic life, except for the phosphate concentrations, which were much higher than the permitted level of 1 mg/I for effluent water. The high phosphate concentrations in the water were due to effluent received from combined sewage purification works in the area of localities KOR1 and OR1, informal settlements situated alongside the river and agricultural runoff. With the exception of manganese, copper and zinc, the metal concentrations were higher than the recommended guideline limits. All the selected metals were, however, present in much higher concentrations in the sediments, especially iron and aluminium, with the highest concentrations found in the smallest particle sizes of the sediments. The high metal concentrations in the water and sediment indicated some degree of metal pollution, but due to the hardness of the water, these metals were not necessarily acutely toxic to the aquatic organisms. The general order of bioaccumulation of the selected metals was, in decreasing concentrations: Fe, Cr, Al, Ni, Pb, Zn, Mn and Cu in the water and: Al, Fe, Mn, Cu, Cr, Ni, Zn and Pb for the sediment, with exceptionally high concentrations of aluminium and iron. The different organs/tissues of the two species bioaccumulated different levels of the metals and it was clear which organs/tissues accumulated higher concentrations of a certain metal. The gills and liver tissues bioaccumulated the highest metal concentrations, with
iii the highest concentrations of copper and iron found in the liver.
These tissues should therefore be used for determining of the bioaccumulation of these metals in the fish. Although the lowest metal concentrations were found in the muscle and skin tissues, these tissues should always be included in general biomonitoring programmes, as it is consumed by humans and especially in this case, by the people from informal settlements located alongside the river, as well as anglers at locality OR1. High metal concentrations were found in the fish tissue, but concentrations in the muscle and skin tissue were still fit for human consumption. These concentrations should, however, always be monitored, as locality KOR1 receives effluent from combined sewage purification works located upstream from it, as well as raw sewage from informal settlements, different industries and urban and agricultural runoff. In addition to these sources, locality OR1 also receives effluent from mainly coal mines, situated in the catchment area. The results showed dependence of the bioaccumulation of most of the metals in the tissues/organs of both species, on the species and lengths of the fish, as well as the localities where the fish were collected. It is widely accepted that the water characteristics may influence the chemical form, availability and toxicity of various metals to aquatic organisms. The establishment of a general biomonitoring programme is therefore needed, where the hydrological and geomorphological characteristics, the chemical and physical water quality and the riparian vegetation are also considered, because these all affect the aquatic ecosystem.
Identification of the lethal as well as sublethal effects of chemicals on living organisms is critical in evaluating and predicting the impacts of metal pollution. As previously stated, sublethal exposure of fish was performed to investigate the effects of aluminium and low pH, as these have caused fish kills in the catchment. Aluminium has different effects at different pH values and maximum toxicity occurs over the pH range 5.0 - 5.5. The fish were therefore exposed to pH 5.2, as well as combinations of pH 5.2 and
iv different concentrations of aluminium. These concentrations were chosen with respect to concentrations found in the Olifants River and its tributaries during the present study. The results indicated sublethal effects (especially on the carbohydrate metabolism) of the fish at these concentrations and pH value. The pH values at the two localities used for description in this study were much higher, thus no serious aluminium toxicity to aquatic organisms is proposed. There are, however, problems with low pH at other localities of the upper catchment. Decreases in the pH values at localities KOR1 and OR1 due to acid mine drainage or low flow of the river, could cause serious problems, as the aluminium concentrations at these two localities in the sediments are very high and can lead to fish kills.
Nutritionally and recreationally, fish constitute the most important segment of the aquatic ecosystem and therefore metal concentrations in fish are obviously of great concern. High concentrations of metals are toxic to the ecosystem as a hole and to humans in particular, since they are at the end of a variety of food chains by virtue of a varied diet. Further research is therefore needed as high concentrations of metals were found in the tissues and organs of the fish, as well as the sediment and water. It is suggested that the sources of pollution in the study area should be further investigated to fully understand the impact they have on the deteriorating environment. A detailed water quality biomonitoring programme of the study area should also be established by the Department of Water Affairs and Forestry and conducted as frequently as possible. The laboratory investigations on the sublethal and lethal effects of metals on indigenous fish species should be continued and expanded as this would enable scientists to update the Water quality index, Water 2, currently being assessed as a management tool to protect aquatic freshwater fish species.
v -UITTREKSEL-
Die bolope van die Olifantsrivier, vanaf die oorsprong naby Bethal tot die samevloei met die Wilgerivier noord van Witbank, asook die sytakke, word beinvloed deur bedrywighede soos boomaanplantings, mynbou, kragopwekking, besproeiing, verstedeliking en nywerheidsontwikkeling. Hierdie aktiwiteite het beslis 'n effek op die waterkwaliteit van die rivier. Die belangrikste puntbronne van besoedeling in die studie gebied sluit myne en industries in, maar die belangrikste is naasliggende gekombineerde riool suiweringswerke. Die behandelde rioolwater bevat oksideringstowwe, wasmiddels, nutriente en metale. Die mate waartoe hierdie aktiwiteite die waterkwaliteit van die rivier beinvloed, moes daarom vasgestel word. Hierdie doel is bereik deur die chemiese en fisiese eienskappe van die rivierwater te bepaal en te evalueer teenoor bestaande waterkwaliteitsriglyne. Spesiale aandag is aan die konsentrasies van geselekteerde metale in die water en sediment, asook in sekere vis spesies gegee, wat daarvoor bekend is om hierdie elemente te akkumuleer.
Die bioakkumulering van mangaan, koper, lood, chroom, yster, sink, nikkel en aluminium in die water en sediment is ook ondersoek. Vis is by die twee lokaliteite gedissekteer waar monitering plaasgevind het. Die lokaliteite is voor die samevloei van die Olifants- rivier (lokaliteit OR1) en die Klein Olifantsrivier (lokalitiet KOR1) gegee. Die skerptand baber, Clarias gariepinus en die moggel Labeo umbratus is vir analise versamel. Vier weefsel tipes naamlik spier-, lewer-, vel- en kieuweefsel is uitgedissekteer. Die konsentrasies van mangaan, koper, lood, chroom, nikkel, aluminium, yster en sink in hierdie organe en weefsels, sowel as in die water en sediment, is in die laboratorium met behulp van 'n Atoomabsorpsiespektrofotometer bepaal. Die resultate verkry is statisties ge-analiseer om die graad van bioakkumulering van hierdie metale in die water en sediment vas te stel. Die vlakke van bioakkumulering in die visweefsel en organe en
vi die afhanldikheid daarvan van die grootte, geslag en spesie van die vis, asook die lokaliteite en seisoene waartydens die vis versamel is, is ook bestudeer.
Daar is bevind dat die waterkwaliteitsveranderlikes meestal binne die voorgestelde grense van die waterkwaliteitsriglyne was, behalwe die fosfaatkonsentrasies, wat aansienlik hoer was as die toelaatbare 1 mg/1 vir afloop water. Hierdie hoe fosfaatkonsentrasies in die water, kan toegeskryf word aan afvloei vanaf gekombineerde rioolsuiweringswerke in the omgewing van die twee lokaliteite. Rou riool vanaf informele huisvestings en afvloei vanaf landerye het ook hiertoe bygedra. Met die uitsondering van mangaan, koper en sink, was die metaalkonsentrasies in die water hoer as die toelaatbare perke. Hierdie metale was egter teenwoordig in baie hoer konsentrasies in die sediment, veral yster en aluminium, met die hoogste konsentrasies in die kleinste partikel groottes van die sediment. Die hoe metaalkonsentrasies in die water en sediment dui op 'n bepaalde vlak van metaalbesoedeling, maar omdat die water van die Olifants Rivier redelik hard is, is die toestande nie noodwendig toksies vir die akwatiese lewe nie. Die algemene vlak van bioakkumulering van die geselekteerde metale is, in afnemende konsentrasies, soos volg: Fe, Cr, Al, Ni, Pb, Zn, Mn en Cu in die water, en: Al, Fe, Mn, Cu, Cr, Ni, Zn en Pb in die sediment met uitsonderlike hoe konsentrasies van aluminium en yster. Die verskillende organe en weefseltipes van die twee spesies, het die metale op verskillende vlakke bevat en daar kon duidelik afgelei word watter organe of weefseltipes die hoogste konsentrasies van 'n bepaalde metaal ge-akkumuleer het. Die kieu- en lewerweefsel het die hoogste konsentrasies van die metale getoon, met koper- en ysterkonsentrasies, die hoogste in die lewer. Hierdie organe kan dus altyd nuttig gebruik word vir die bepaling van die bioakkumulering van die genoemde metale in vis. Alhoewel die laagste metaal konsentrasies in die spier- en velweefsel teenwoordig is, is dit noodsaaklik dat hierdie weefsels altyd ingesluit moet word in algemene biomoniteringsprogramme, aangesien dit die eetbare deel van die vis is. Die bevolking van informele behuising benut vis uit die natuurlike strome as voedselbron. Die geskiktheid van die vis as
vii proteIen bron moet daarom vasgestel word. Ten spyte van die hoe metaalkonsentrasies in organe soos die kieue en lewer is die metaalvlakke in die vel- en spierweefsel binne perke. Hierdie vis kan daarom as voedselbron benut word. Metaal konsentrasies moet daarom altyd gemoniteer word, aangesien lokaliteit KOR1 afvloei ontvang vanaf gekombineerde rioolsuiweringswerke (stroom-op), sowel as rou riool vanaf die informele huisvestings. Afloopwater van verskeie kragsentrales, industries en stedelike gebiede en landelike omgewing hou ook 'n besoedelings gevaar in. Bykomend tot hierdie bronne, ontvang lokaliteit OR1 nog afloopwater vanaf steenkoolmyne in die area. Die resultate het 'n athanldikheid- van die bioakkumulering van die meeste metale in die organe en weefsel van die twee spesies getoon, met die spesifieke spesie en lengtes van die visse, sowel as die lokaliteite waar hierdie visse gevang is. Waterkwaliteitseienskappe beinvloed die chemiese vorme, beskikbaarheid en toksisiteit van verskeie metale vir akwatiese organismes. Daarom is die daarstelling van 'n algemene biomoniteringsprogram van groot belang, waar die hidrologiese en geomorfologiese eienskappe, die chemiese en fisiese water kwaliteit en die oewer plantegroei ook in ag geneem word. Hierdie faktore bepaal die eienskappe van akwatiese ekosisteme.
Identifisering van die effekte van chemikaliee op lewende organismes is belangrik om sodoende die metaalbesoedeling te kan beheer. Bykomend tot die veldstudie, is toksisiteitstoetse ook in die laboratorium uitgevoer, om sodoende die effekte van laer pH vlakke en verhoogde konsentrasies van aluminium op die hematologie, osmoregulering en koolhidraatmetabolisme van die bloukurpur, Oreochromis mossambicus, te bepaal. Die pH waarde van 5.2 is gebruik aangesien die maksimum toksisiteit van aluminium tussen pH 5.0 en 5.5 aangetref word. Aluminium het verskillende effekte by verskillende pH waardes en blootstelling aan 'n lae pH is gedoen, aangesien versuring die oplossing van aluminium in akwatiese sisteme veroorsaak. Die aluminiumkonsentrasies gebruik in hierdie studie, is gekies volgens die konsentrasies teenwoordig in die Olifantsrivier en die sytakke soos gedurende die huidige studie vasgestel. Die resultate het definitiewe
viii subletale effekte getoon, veral op koolhidraatmetabolisme. Die pH-vlakke by die twee lokaliteite wat bestudeer is, is aansienlik hoer as die pH waarby die eksperimente uitgevoer is. Geen ernstige aluminiumtoksisiteit vir akwatiese organismes kan daarom by die betrokke twee lokaliteite verwag word nie. Die lae pH by ander lokaliteite in die opvangsgebied van die Olifantsrivier en verlaging van die pH vlakke by lokaliteite KOR1 en OR1, as gevolg van suur afloop vanaf myne of laagvloei van die rivier, kan die voortbestaan van die vis bedreig. Die rede hiervoor is die hoe aluminiumkonsentrasies by hierdie twee lokaliteite in die sediment en oplossing daarvan in die water deur verlaagde pH wat tot visvrektes kan lei.
Uit die oogpunt van voeding en ontspanning, beslaan vis die belangrikste posisie in die akwatiese ekosisteem en daarom is die vlak van metaalkonsentrasies in visweefsel vanselfsprekend van groot belang. Hoe konsentrasies van metale is toksies vir die ekosisteem as 'n geheel en veral vir die mens wat die eindverbruiker in 'n verskeidenheid voedselkettings is. Verdere navorsing is nodig, aangesien hoe konsentrasies van metale in die weefsels en organe van die vis, asook in die sediment en water voorkom. Navorsing behoort op die bronne van besoedeling in die studie area toegespits te wees sodat die impak daarvan op die agteruitgang van die omgewing vasgestel kan word. Vanuit die bevindinge van hierdie studie is dit duidelik dat 'n gereelde moniteringsprogram wat waterkwaliteit en bioakkumulering insluit, deur die Departement van Waterwese en Bosbou oorweeg behoort te word.
ix - TABLE OF CONTENTS -
INTRODUCTION 1-1
1.1 References 1 - 7
THE OLIFANTS RIVER BASIN AND LOCALITY DESCRIPTION 2 - 1
2.1 General description 2-1 2.2 Sources of water 2-3 2.2.1 Groundwater 2-3 2.2.2 Surface water 2-4 2.2.3 Reuse of effluent 2-7 2.3 Water user sectors 2-7 2.3.1 Afforestation 2-7 2.3.2 Power generation 2-10 2.3.3 Mining 2-10 2.3.4 Irrigation 2-11 2.3.5 Stock watering 2-11 2.3.6 Domestic and industrial 2-11 2.4 Water quality 2-12 2.5 The study area 2-17 2.6 References 2-20
WATER AND SEDIMENT 3 - 1
3.1 Introduction 3-1 3.2 Materials and methods 3-4 3.2.1 Water 3-4 3.2.2 Sediment 3-5 3.2.3 Data processing 3-7 3.3 Results 3-7 3.3.1 Water 3-7 3.3.2 Sediment 3-23 3.4 Discussion 3-35 3.4.1 Physical and chemical characteristics of the river water 3-35 3.4.2 Metal concentrations in the water and sediment 3-43 3.5 Conclusion 3-46 3.6 References 3-49 3.7 Appendixes 3-56
1 BIOACCUMULATION OF ZINC AND COPPER IN THE TISSUES AND ORGANS OF GLARUS GARIEPINUS AND LABEO UMBRATUS 4-1
4.1 Introduction 4-1 4.2 Materials and methods 4-4 4.2.1 Field sampling 4-4 4.2.2 Laboratory procedures 4-4 4.2.3 Statistical procedures 4-8 4.3 Results 4-9 4.3.1 Fish size 4-9 4.3.2 Differences in bioaccumulation of zinc and copper in the different tissues/organs 4-9 4.3.3 Species differences 4-16 4.3.4 Relationship between lengths and zinc and copper concentrations 4-20 4.3.5 Differences between males and females 4-20 4.3.6 Seasonal differences 4-26 4.3.7 Localities differences 4-26 4.4 Discussion 4-30 4.5 Conclusion 4-40 4.6 References 4-42 4.7 Appendixes 4-48
BIOACCUMULATION OF MANGANESE AND LEAD IN THE TISSUES AND ORGANS OF CLARIAS GARIEPINUS AND LABEO UMBRATUS 5-1
5.1 Introduction 5-1 5.2 Materials and methods 5-3 5.3 Results 5-3 5.3.1 Differences in bioaccumulation of manganese and lead in the different tissues/organs 5-3 5.3.2 Species differences .5-7 5.3.3 Relationship between lengths and manganese and lead concentrations 5-11 5.3.4 Differences between males and females 5-11 5.3.5 Seasonal differences 5-11 5.3.6 Localities differences 5-15 5.4 Discussion 5-19 5.5 Conclusion 5-29 5.6 References 5-30 5.7 Appendixes 5-33
2 BIOACCUMULATION OF CHROMIUM AND NICKEL IN THE TISSUES AND ORGANS OF CLARIAS GARIEPINUS AND LABEO UMBRATUS 6-1
6.1 Introduction 6-1 6.2 Materials and methods 6-3 6.3 Results 6-3 6.3.1 Bioaccumulation of chromium and nickel in the different tissues/organs 6-3 6.3.2 Species differences 6-11 6.3.3 Relationship between lengths and chromium and nickel concentrations 6-11 6.3.4 Differences between males and females 6-11 6.3.5 Seasonal differences .6-14 6.3.6 Localities differences 6-14 6.4 Discussion 6-21 6.5 Conclusion .6-27 6.6 References 6-29 6.7 Appendixes 6-34
BIOACCUMULATION OF ALUMINIUM AND IRON IN THE TISSUES AND ORGANS OF CLAMS GARIEPINUS AND LABEO UMBRATUS 7-1
7.1 Introduction 7-1 7.2 Materials and methods 7-3 7.3 Results 7-3 7.3.1 Differences in bioaccumulation of aluminium and iron in the different tissues/organs 7-3 7.3.2 Species differences 7-11 7.3.3 Relationship between lengths and aluminium and iron concentrations 7-11 7.3.4 Differences between males and females 7-16 7.3.5 Seasonal differences 7-16 7.3.6 Localities differences 7-16 7.4 Discussion 7-20 7.5 Conclusion 7-27 7.6 References 7-28 7.7 Appendixes 7-32
THE EFFECTS OF LOW PH AND ALUMINIUM ON THE HAEMATOLOGY, OMOREGULATION AND CARBOHYDRATE METABOLISM OF OREOCHROMIS MOSSAMBICUS 8-1
8.1 Introduction 8-1
3 8.2 Materials and methods 8-3 8.2.1 Experimental procedure 8-6 8.2.1.1 Exposure of the test organism 8-6 8.2.1.2 Controls 8-16 8.2.1.3 Blood sampling 8-16 8.2.1.4 Measurement of variables .8-16 8.2.1.5 Data processing 8-20 8.3 Results 8-20 8.4 Discussion 8-26 8.5 Conclusion 8-38 8.6 References 8-40 8.7 Appendixes .8-47
9. SUMMARY AND RECOMMENDATIONS 9 - 1
9.1 General summary 9-1 9.1.1 Water and sediment .9-1 9.1.2 Bioaccumulation of the selected metals in the tissues and organs of C. gariepinus and L.umbratus 9-3 9.1.3 Toxicity tests of low pH and elevated aluminium concentrations on the haematology, osmoregulation and carbohydrate metabolism of the Mozambique tilapia, Oreochromis mossambicus 9-6 9.2 Recommendations 9-7
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INTRODUCTION
The use of metals for industrial, mining and agricultural purposes and the subsequent occurrence as trace contaminants, have resulted in increased loadings thereof in the aquatic environment. Diffuse and point source pollution from these activities contribute significantly towards metal and organic contamination, acidification and mineralization of the surface waters. Many potential contaminants, for example metals, ultimately find their way into surface waters which are the natural habitats for a large variety of aquatic species. It is therefore of primary importance to determine the effects of these contaminants on the water and sediment quality, as well as the degree of bioaccumulation of these pollutants by the fish and other aquatic biota.
All metal ions are potentially harmful to organisms at some level of exposure and absorption. The ecological significance of metals stems from their general toxicity and the fact that they are non-biodegradable. Metals vary widely in their physical, chemical and biological properties and can be found in several different forms after entering the water (Fig 1-1). In the aquatic environment, metals may exist in the dissolved form as free hydrated ions; as complex and chelated ions with inorganic ligands, including OH -, C032-, Cl- or as organic ligands including amines, proteins, humic acids and fulvic acids, or as part of organic molecules. Metals can also exist in the particulate form as colloidal complexes or aggregates, adsorbed on different types of particles, precipitated (for example as metal coatings on particles), or incorporated in organic particles such as plankton.
1-1 •
Introduction
Metal form -) Inorganic Soluble -> Ion Complex --+ Chelate -+ Molecule
-> Organic Particulate -■ Colloid Adsorption -> Suspended
-> Carrier particles -+ Mineral detritus Clay minerals Humic substances Lipids --* Residual organics --* Hydrous Fe/Mn oxides Carbonates