Health assessment of freshwater fish species from Albasini Dam, outside a DDT-sprayed area in Limpopo province, South Africa: a preliminary study

References

• Adams SM, Brown AM, Goede RW. 1993. A quantitative Health Assessment Index for rapid evaluation of fish condition in the field. Transactions of the American Fisheries Society 122: 63–73. doi: 10.1577/1548-8659(1993)122<0063:AQHAIF>2.3.CO;2
   Web of Science ®Google Scholar
• Adeyemo OK, Agbede SA, Olaniyan AO, Shoaga OA. 2003. The haematological response of Clarias gariepinus to changes in acclimation temperature. African Journal of Biomedical Research 6: 105–108.
   Google Scholar
• Addo-Bediako A, Marr SM, Jooste A, Luus-Powell WJ. 2014. Are metals in the muscle tissue of Mozambique tilapia a threat to human health? A case study of two impoundments in the Olifants River, Limpopo, South Africa. International Journal of Limnology 50: 201–210. doi: 10.1051/limn/2014091
   Web of Science ®Google Scholar
• Akan JC, Mohmoud S, Yikala BS, Ogugbuaja VO. 2012. Bioaccumulation of some heavy metals in fish samples from River Benue in Vinikilang, Adamawa State, Nigeria. American Journal of Analytical Chemistry 3: 727–736. doi: 10.4236/ajac.2012.311097
   Google Scholar
• APHA (American Public Health Association). 1992. Standard methods for the examination of water and wastewater (18th edn). Washington, DC: American Public Health Association.
   Google Scholar
• ATSDR (Agency for Toxic Substances and Disease Registry). 1992. Toxicological profile for aluminium. Atlanta, Georgia: ATSDR (TP-91/01), US Department of Health and Human Services, Public Health Service.
   Google Scholar
• ATSDR (Agency for Toxic Substances and Disease Registry). 1994. Toxicological profile for chlordane. Atlanta, Georgia: ATSDR, US Department of Health and Human Services, Public Health Service.
   Google Scholar
• ATSDR (Agency for Toxic Substances and Disease Registry). 2002. Toxicological profile for methoxychlor. Atlanta, Georgia: ATSDR, US Department of Health and Human Services, Public Health Service.
   Google Scholar
• Avenant-Oldewage A, Marx HM. 2000. Bioaccumulation of chromium, copper and iron in organs and tissues of Clarias gariepinus in the Olifants River, Kruger National Park. Water SA 26: 569–582.
   Web of Science ®Google Scholar
• Barnhoorn IEJ, Bornman MS, Pieterse GM, van Vuren JHJ. 2004. Histological evidence of intersex in feral sharptooth catfish (Clarias gariepinus) from an estrogen-polluted water source in Gauteng, South Africa. Environmental Toxicology 19: 603–608. doi: 10.1002/tox.20068
   PubMed Web of Science ®Google Scholar
• Barnhoorn IEJ, van Dyk JC, Genthe B, Harding WR, Wagenaar GM, Bornman MS. 2015. Organochlorine pesticide levels in Clarias gariepinus from polluted freshwater impoundments in South Africa and associated human health risks. Chemosphere 120: 391–397. doi: 10.1016/j.chemosphere.2014.08.030
   PubMed Web of Science ®Google Scholar
• Barnhoorn IEJ, van Dyk JC, Pieterse GM, Bornman MS. 2010. Intersex in feral indigenous freshwater Oreochromis mossambicus from various parts in the Luvuvhu River, Limpopo Province, South Africa. Ecotoxicology and Environmental Safety 73: 1537–1542. doi: 10.1016/j.ecoenv.2010.07.026
   PubMed Web of Science ®Google Scholar
• Bernet D, Schmidt H, Meier W, Burkhardt-Holm P, Wahli T. 1999. Histopathology in fish: proposal for a protocol to assess aquatic pollution. Journal of Fish Diseases 22: 25–34. doi: 10.1046/j.1365-2761.1999.00134.x
   Web of Science ®Google Scholar
• Bester BM. 2014. An assessment of the health status and edibility of fish from three impoundments in the North West Province, South Africa. MSc thesis, University of Johannesburg. Available at http://hdl.handle.net/10210/11404.
   Google Scholar
• Bornman MS, Barnhoorn IEJ, Genthe B (eds). 2010. DDT for malaria control: effects in indicators and health risk. WRC Report No. 1674/1/09. Pretoria: Water Research Commission.
   Google Scholar
• Botha AM, Oberholster PJ. 2007. PCR-Based Markers for Detection and identification of toxic cyanobacteria. WRC Report No. K5/1502/01/07. Pretoria: Water Research Commission.
   Google Scholar
• Botha TL. 2011. A histology-based fish health assessment to determine the health and reproductive status of Clarias gariepinus in the Hartbeespoort Dam, South Africa. MSc thesis, University of Johannesburg, South Africa. Available at https://ujdigispace.uj.ac.za/ [accessed 20 June 2013].
   Google Scholar
• Bouwman H. 2004 South Africa and the Stockholm convention on persistent organic pollutants. South African Journal of Science 100: 323–328.
   Web of Science ®Google Scholar
• Camargo JA, Alonso A, Salamanca A. 2005. Nitrates toxicity to aquatic animals: A review with new data for freshwater invertebrates. Chemosphere 58: 1255–1267. doi: 10.1016/j.chemosphere.2004.10.044
   PubMed Web of Science ®Google Scholar
• Cardwell RD, Foreman DG. Payne TR, Wilbur DG. 1977. Acute and chronic toxicity of chlordane to fish and invertebrates. EPA 600/3-77-019. U.S. Environmental Protection Agency. Available at http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=9101XGCJ.PDF [accessed 08 September 2015].
   Google Scholar
• Carlander KD (ed.). 1969. Handbook of freshwater fishery biology. Iowa: Iowa State University Press.
   Google Scholar
• Carpenter DO. 2013. Effects of persistent and bioactive organic pollutants on human health (1st edn). Hoboken, New Jersey: John Wiley and Sons.
   Google Scholar
• DAFF (Department of Agriculture, Forestry and Fisheries). 2010. Fertilizers, farm feeds, agricultural remedies and stock remedies act, 1947 (Act No. 36 of 1947): adoption of pesticide management policy for South Africa. General Notice 1120 of 2010. Government Gazette, South Africa 546(33899). Available at http://www.environment.co.za/environmental-laws-and-legislation-in-south-africa/pesticide-management-policy-for-south-africa.html [accessed 20 August 2014].
   Google Scholar
• Danish Veterinary and Food Administration. 2003. Combined actions and interactions of chemicals in mixtures: the toxicological effects of exposure to mixtures of industrial and environmental chemicals. Fødevare Rapport 2003:12 (1st edn). Available at www.fdir.dk [accessed 25 August 2015].
   Google Scholar
• DEAT (Department of Environmental Affairs and Tourism). 2006. South Africa environment outlook. A report on the state of the environment. Executive summary and key findings. Pretoria: DEAT.
   Google Scholar
• de Boek G, Eyckmans M, Lardon I, Bobbaers R, Sinha AK, Blust R. 2010. Metal accumulation and metallothionein induction in the spotted dogfish Scyliorhinus canicula. Comparative Biochemistry and Physiology, Part A 155: 503–508. doi: 10.1016/j.cbpa.2009.12.014
   PubMed Web of Science ®Google Scholar
• DWAF (Department of Water Affairs and Forestry). 1996. South African water quality guidelines. Vol. 7: aquatic ecosystems. Pretoria: Department of Water Affairs and Forestry.
   Google Scholar
• DWAF (Department of Water Affairs and Forestry). 2001. State of the rivers report: the Letaba and Luvuvhu River systems. The River Health Programme. Pretoria: Department of Water Affairs and Forestry.
   Google Scholar
• DWAF (Department of Water Affairs and Forestry). 2003. National Eutrophication monitoring programme (2002–2003). Pretoria: Department of Water Affairs and Forestry. Available at http://www.dwaf.gov.za/iwqs/eutrophication/NEMP/report/NEMP_2002-10-01_2003-03-31.htm [accessed 7 November 2014].
   Google Scholar
• Faires ML. 1993. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory determination of metals in water by Inductively Coupled Plasma-Mass Spectrometry. Open-File Report No. 92–634. Colorado: U.S Geological Survey.
   Google Scholar
• Fanta E, Rios FS, Romao S, Vianna ACC, Freiberger S. 2003. Histopathology of the fish Corydoras paleatus contaminated with sub lethal levels of organophosphorus in water and food. Ecotoxicology and Environmental Safety 54: 119–130. doi: 10.1016/S0147-6513(02)00044-1
   PubMed Web of Science ®Google Scholar
• FAO (Food and Agriculture Organization). 1994. Population and water resources. FAO and POPIN (United Nations Population Information Network). Available at http://www.un.org/popin/fao/water.html [accessed 17 November 2014].
   Google Scholar
• Freedman B. 1995. Environmental ecology: the ecological effects of pollution, disturbance, and other stresses (2nd edn). San Diego: Academic Press.
   Google Scholar
• Geissen V, Mol H, Klumpp E, Umlauf G, Nadal M, van der Ploeg M, van de Zee SEATM, Ritsema CJ. 2015. Emerging pollutants in the environment: A challenge for water resource management. International Soil and Water Conservation Research 3: 57–65. doi: 10.1016/j.iswcr.2015.03.002
   Web of Science ®Google Scholar
• Gilbert B, Avenant-Oldewage A. 2014. Arsenic, chromium, copper, iron, manganese, lead, selenium and zinc in the tissues of the largemouth yellowfish, Labeobarbus kimberleyensis (Gilchrist and Thompson, 1913), from the Vaal Dam, South Africa, and associated consumption risks. Water SA 40: 739–748. doi: 10.4314/wsa.v40i4.19
   Web of Science ®Google Scholar
• Grobler DF, Kempster PL, van der Merwe L. 1994. A note on the occurrence of metals in the Olifants River, Eastern Transvaal, South Africa. Water SA 20: 195–204.
   Web of Science ®Google Scholar
• Hedden S, Cilliers J. 2014. Parched prospects: the emerging water crisis in South Africa. African Futures Paper 11. Institute for Security Studies (ISS). Available at https://www.issafrica.org/publications/papers/parched-prospects-the-emerging-water-crisis-in-south-africa [accessed 23 August 2015].
   Google Scholar
• Hogan CM. 2014. Encyclopedia of Earth: water pollution. Available at http://www.eoearth.org/view/article/156920/ [accessed 17 November 2014].
   Google Scholar
• Humason GL. 1979. Animal tissue techniques (4th edn). New York: Freeman and Company.
   Google Scholar
• Jezierska B, Sarnowski P. 2002. The effect of mercury, copper and cadmium during single and combined exposure on oxygen consumption of Oncorhynchus mykiss Wal. and Cyprinus carpio L. larvae. Archives of Polish Fisheries 10: 15–22.
   Google Scholar
• Jezierska B, Witeska M. 2001. Metal toxicity to fish. Siedlce: University of Podlasie.
   Google Scholar
• Jooste A, Marr SM, Addo-Bediako A, Luus-Powell WJ. 2015. Sharptooth catfish shows its metal: a case study of metal contamination at two impoundments in the Olifants River, Limpopo river system, South Africa. Ecotoxicology and Environmental Safety 112: 96–104. doi: 10.1016/j.ecoenv.2014.10.033
   PubMed Web of Science ®Google Scholar
• Kongtorp RT, Halse M, Taksdal T, Falk K. 2006. Longitudinal study of a natural outbreak of heart and skeletal muscle inflammation in Atlantic salmon, Salmo salar L. Journal of Fish Diseases 29: 233–244. doi: 10.1111/j.1365-2761.2006.00710.x
   PubMed Web of Science ®Google Scholar
• Laetz CA, Baldwin DH, Collier TK, Hebert V, Stark JD, Scholz NL. 2009. The synergistic toxicity of pesticide mixtures: implications for risk assessment and the conservation of endangered pacific salmon. Environmental Health Perspectives 117: 348–353. doi: 10.1289/ehp.0800096
   PubMed Web of Science ®Google Scholar
• Lawrence A, Hemingway KL (eds). 2003. Effects of pollution on fish: molecular effects and population responses. Oxford: Blackwell.
   Google Scholar
• Lewis M. 1978. Acute toxicity of copper, zinc and manganese in single and mixed salt solutions to juvenile longfin dace, Agosia chrysogaster. Journal of Fish Biology 13: 695–700. doi: 10.1111/j.1095-8649.1978.tb03483.x
   Web of Science ®Google Scholar
• Lujić J, Matavulj MD, Poleksic V, Raskovic B, Marinovic Z, Kostic DS, Miljanovic BM. 2015. Gill reaction to pollutants from the Tamis River in three freshwater fish species, Esox lucius L. 1758, Sander lucioperca (L. 1758) and Silurus glanis L. 1758: A comparative study. Anatomia, Histologia, Embryologia 44: 128–137. doi: 10.1111/ahe.12119
   PubMed Web of Science ®Google Scholar
• Mallatt J. 1985. Fish gills structural changes induced by toxicants and other irritants: a statistical review. Canadian Journal of Fisheries and Aquatic Sciences 42: 630–648. doi: 10.1139/f85-083
   Web of Science ®Google Scholar
• Marchand MJ. 2006. Histopathological assessment of selected organs as a bio-monitoring tool to assess the health status of Clarias gariepinus in two dams in the Rietvlei Nature Reserve. MSc thesis, University of Johannesburg, South Africa. Available at https:ujdigispace.uj.ac.za [accessed 10 October 2014].
   Google Scholar
• Marchand MJ, Pieterse GM, Barnhoorn IEJ. 2008. Preliminary results on sperm motility and testicular histology of two feral fish species, Oreochromis mossambicus and Clarias gariepinus, from a currently DDT-sprayed area, South Africa. Journal of Applied Ichthyology 24: 423–429. doi: 10.1111/j.1439-0426.2008.01141.x
   Web of Science ®Google Scholar
• Marchand MJ, van Dyk JC, Barnhoorn IEJ, Wagenaar GM. 2012. Histopathological changes in two potential indicator fish species from a hyper-eutrophic freshwater ecosystem in South Africa: a baseline study. African Journal of Aquatic Science 37: 39–48. doi: 10.2989/16085914.2011.636902
   Web of Science ®Google Scholar
• Marchand MJ, van Dyk JC, Pieterse GM, Barnhoorn IEJ, Bornman MS. 2009. Histopathological alterations in the liver of the sharptooth catfish Clarias gariepinus from polluted aquatic systems in South Africa. Environmental Toxicology 24: 133–147. doi: 10.1002/tox.20397
   PubMed Web of Science ®Google Scholar
• Marx HM, Avenant-Oldewage A. 1998. A further investigation into the bioaccumulation of lead and zinc in the organs and tissues of the African catfish Clarias gariepinus from two localities in the Olifants River, Kruger National Park. Koedoe 41: 27–43. doi: 10.4102/koedoe.v41i2.251
   Google Scholar
• McHugh KJ, Smit NJ, van Vuren JHJ, van Dyk JC, Bervoets L, Covaci A, Wepener V. 2011. A histology-based fish health assessment of the tigerfish Hydrocynus vittatus from a DDT-affected area. Physics and Chemistry of the Earth 36: 895–904. doi: 10.1016/j.pce.2011.07.077
   Web of Science ®Google Scholar
• Mlambo SS, van Vuren JHJ, Barnhoorn IEJ, Bornman MS. 2009. Histopathological changes in the reproductive system (ovaries and testes) of Oreochromis mossambicus following exposure to DDT. Environmental Toxicology and Pharmacology 28: 133–139. doi: 10.1016/j.etap.2009.03.011
   PubMed Web of Science ®Google Scholar
• Mooney A. 2012. An assessment of the health status and edibility of fish from three impoundments in the North West Province, South Africa. MSc thesis, University of Johannesburg. https:ujdigispace.uj.ac.za [accessed 09 October 2014].
   Google Scholar
• Odiyo JO, Chimuka L, Mamali MA, Fatoki OS. 2012. Trophic status of Vondo and Albasini Dams; impacts on aquatic ecosystems and drinking water. International Journal of Environmental Science and Technology 9: 203–218. doi: 10.1007/s13762-012-0034-x
   Web of Science ®Google Scholar
• Olujimi OO, Fatoki OS, Odendaal JP, Okonkwo JO. 2010. A review of endocrine disrupting chemicals (phenol and phthalates) in the South African environment: a need for more monitoring. Water SA 36: 671–682. doi: 10.4314/wsa.v36i5.62001
   Web of Science ®Google Scholar
• Palacios G, Lovoll M, Tengs T, Hornig M, Hutchison S, Hui J et al. 2010. Heart and skeletal muscle inflammation of farmed salmon is associated with infection with a novel reovirus. PLoS ONE 5: e11487. doi: 10.1371/journal.pone.0011487
   Google Scholar
• Perschbacher PW, Wurts WA. 1999. Effects of calcium and magnesium hardness on acute copper toxicity to juvenile channel catfish Ictalurus punctatus. Aquaculture 172: 275–280. doi: 10.1016/S0044-8486(98)00499-2
   Web of Science ®Google Scholar
• Pieterse GM, Marchand MJ, van Dyk JC, Barnhoorn IEJ. 2010. Histological alterations in the testes and ovaries of the sharptooth catfish (Clarias gariepinus) from an urban nature reserve in South Africa. Journal of Applied Ichthyology 26: 789–793. doi: 10.1111/j.1439-0426.2010.01557.x
   Web of Science ®Google Scholar
• Quin LP, de Vos BJ, Fernandes-Whaley M, Roos C, Bouwman H, Kylin H et al. 2011. Pesticide use in South Africa: one of the largest importers of pesticides in Africa. In: Stoytcheva M (ed.), Pesticides in the modern world: pesticides use and management,. Rijeka: InTech. pp 49–96.
   Google Scholar
• Rašković B, Jarić I, Koko V, Spasić M, Dulić Z, Marković Z, Poleksić V. 2013. Histopathological indicators: a useful fish health monitoring tool in common carp (Cyprinus carpio Linnaeus, 1758) culture. Central European Journal of Biology 8: 975–985.
   Google Scholar
• Reddy PB, Rawat SS. 2013. Assessment of aquatic pollution using histopathology in fish as a protocol. International Research Journal of Environment Science 2: 79–82.
   Google Scholar
• Roberts RJ. 2001. Fish pathology (3rd edn). Philadelphia, Pennsylvania: WB Saunders.
   Google Scholar
• Robinson J, Avenant-Oldewage A. 1997. Chromium, copper, iron and manganese bioaccumulation in some organs and tissues of Oreochromis mossambicus from the lower Olifants River inside the Kruger National Park. Water SA 23: 387–403.
   Web of Science ®Google Scholar
• Roy R, Campbell PGC. 1995. Survival time modelling of exposure of juvenile Atlantic salmon (Salmo salar) to mixtures of aluminium and zinc in soft water at low pH. Aquatic Toxicology 33: 155–176. doi: 10.1016/0166-445X(95)00019-Z
   Web of Science ®Google Scholar
• Saraiva A, Costa J, Serrão J, Cruz C, Eiras JC. 2015. A histology-based fish health assessment of farmed seabass (Dicentrarchus labrax L.). Aquaculture (Amsterdam, Netherlands) 448: 375–381. doi: 10.1016/j.aquaculture.2015.06.028
   Web of Science ®Google Scholar
• Sivarajah H, Franklin CS, Williams WP. 1978. Some histopathological effects of Aroclor 1254 on the liver and gonads of rainbow trout, Salmo gairdneri, and carp, Cyprinus carpio. Journal of Fish Biology 13: 411–414. doi: 10.1111/j.1095-8649.1978.tb03448.x
   Web of Science ®Google Scholar
• Skelton P. 2001. A complete guide to the freshwater fishes of southern Africa (2nd edn). Cape Town: Struik.
   Google Scholar
• Takashima F, Hibiya T. 1995. An atlas of fish histology: normal and pathological features (2nd edn). Stuttgart: Gustav Fischer Verlag.
   Google Scholar
• Thornton JA, Harding WR, Dent M, Hart RC, Lin H, Rast CL et al. 2013. Eutrophication as a ‘wicked’ problem. Lakes and Reservoirs: Research and Management 18: 298–316. doi: 10.1111/lre.12044
   Google Scholar
• Tresise MM. 2014. The use of selected biomarkers to determine the effects of veterinary growth stimulants in the Mozambique tilapia (Oreochromis mossambicus). MSc thesis, University of Johannesburg, South Africa. Available at https:ujdigispace.uj.ac.za [accessed 09 October 2014].
   Google Scholar
• UNEP (United Nations Environment Programme). 2005. Ridding the world of POPs: a guide to the Stockholm convention on persistent organic pollutants. Available at http://www.pops.int/documents/guidance/begguide.pdf [accessed 19 November 2014].
   Google Scholar
• UNEP (United Nations Environment Programme). 2008. Water quality for ecosystems and human health (2nd edn). UNEP Global Environment Monitoring System (GEMS) Water Programme. Available at http://www.unwater.org/wwd10/downloads/water_quality_human_health.pdf [accessed 17 November 2014].
   Google Scholar
• USEPA (United States Environmental Protection Agency). 1999a. Integrated Risk Information System (IRIS) on chlordane. Washington, DC: Office of Research and Development, National Center for Environmental Assessment. Available at http://www.epa.gov/airtoxics/hlthef/chlordan.html [accessed 09 September 2015].
   Google Scholar
• USEPA (United States Environmental Protection Agency). 1999b. Integrated Risk Information System (IRIS) on methoxychlor. Washington, DC: Office of Research and Development, National Center for Environmental Assessment. Available at http://www.epa.gov/airtoxics/hlthef/methoxyc.html [accessed 8 September 2015].
   Google Scholar
• USEPA (United States Environmental Protection Agency). 2000. Guidance for assessing chemical contaminant data for use in fish advisories. Vol. 1: Fish sampling and analysis (3rd edn). Washington, DC: Office of Science and Technology, Office of Water, US Environmental Protection Agency.
   Google Scholar
• USEPA (United States Environmental Protection Agency). 2003. Biopesticides Registration Action Document: 2,6-Diisopropylnaphthalene (PC Code 055803). USEPA, Office of Pesticide Programs. Available at http://www.epa.gov/opp00001/chemsearch/reactions/registration/decisionPC0558031-Oct-03.pdf [accessed 7 November 2014].
   Google Scholar
• USEPA (United States Environmental Protection Agency). 2009. National primary and secondary drinking water regulations. EPA 816-F-09-004. United States Environmental Protection Agency. Available at http://www.epa.gov/ogwdw/consumer/pdf/mcl.pdf [accessed 18 November 2014].
   Google Scholar
• USEPA (United States Environmental Protection Agency). 2014. Nitrogen pollution in water. Available at http://www2.epa.gov/nutrientpollution/problem [accessed 19 November 2014].
   Google Scholar
• Vallack HW, Bakker DJ, Brandt I, Brostrom-Lunden E, Brouwer A, Bull KR, et al. 1998. Controlling persistent organic pollutants – what next? Environmental Toxicology and Pharmacology 6: 143–175. doi: 10.1016/S1382-6689(98)00036-2
   PubMed Web of Science ®Google Scholar
• van Dyk JC. 2006. A qualitative and quantitative assessment of the normal histology of selected target organs of Clarias gariepinus and Oreochromis mossambicus. PhD thesis, University of Johannesburg, South Africa. Available at https:ujdigispace.uj.ac.za [accessed 10 October 2014].
   Google Scholar
• van Dyk JC, Bouwman H, Barnhoorn IEJ, Bornman MS. 2010. DDT contamination from indoor residual spraying for malaria control. Science of the Total Environment 408: 2745–2752. doi: 10.1016/j.scitotenv.2010.03.002
   PubMed Web of Science ®Google Scholar
• van Dyk JC, Marchand MJ, Smit NJ, Pieterse GM. 2009a. A histology-based fish health assessment of four commercially and ecologically important species from the Okavango Delta panhandle, Botswana. African Journal of Aquatic Science 34: 273–282. doi: 10.2989/AJAS.2009.34.3.9.985
   Web of Science ®Google Scholar
• van Dyk JC, Marchand MJ, Pieterse GM, Barnhoorn IEJ, Bornman MS. 2009b. Histological changes in the gills of Clarias gariepinus (Teleostei: Clariidae) from a polluted South African urban aquatic system. African Journal of Aquatic Science 34: 283–291. doi: 10.2989/AJAS.2009.34.3.10.986
   Web of Science ®Google Scholar
• van Dyk JC, Pieterse GM, van Vuren JHJ. 2007. Histological changes in the liver of Oreochromis mossambicus (Cichlidae) after exposure to cadmium and zinc. Ecotoxicology and Environmental Safety 66: 432–440. doi: 10.1016/j.ecoenv.2005.10.012
   PubMed Web of Science ®Google Scholar
• van Ginkel CE. 2011. Eutrophication: present reality and future challenges for South Africa. Water SA 37: 693–701. doi: 10.4314/wsa.v37i5.6
   Web of Science ®Google Scholar
• Wepener V. 1997. Metal ecotoxicology of the Olifants River in the Kruger National Park and the effect thereof on fish haematology. PhD thesis, Rand Afrikaans University, South Africa.
   Google Scholar
• Wepener V, van Vuren JHJ, du Preez HH. 2001. Uptake and distribution of copper, iron and zinc mixture in gill, liver and plasma of a freshwater teleost, Tilapia sparrmanii. Water SA 27: 99–108.
   Web of Science ®Google Scholar
• WHO (World Health Organization). 2010. Persistent organic pollutants: impacts on child health. Geneva: WHO.
   Google Scholar
• WHO (World Health Organization). 2011. Guidelines for drinking-water quality (4th edn.) Geneva: World Health Organization.
   Google Scholar
• Wu Z, Yu Z, Song X, Yuan Y, Cao X, Liang Y. 2013. Application of an integrated methodology for eutrophication assessment: a case study in the Bohai Sea. Chinese Journal of Oceanology and Limnology 31: 1064–1078. doi: 10.1007/s00343-013-2286-9
   Web of Science ®Google Scholar
• Yafa C, Farmer GJ. 2006. A comparative study of acid-extractable and total digestion methods for the determination of inorganic elements in peat material by inductively coupled plasma-optical emission spectrometry. Analytica Chimica Acta 557: 296–303. doi: 10.1016/j.aca.2005.10.043
   Web of Science ®Google Scholar
• Yaru BT, Bainok D, Day GM. 1999. Determination of Cd, Cu, Pb, and Zn in biological tissues using Zeeman Graphite Furnace AAS after microwave digestion in non-pressurized, semi-closed vessel. Atomic Spectroscopy 20: 33–38.
   Web of Science ®Google Scholar