Metal concentrations in Clarias gariepinus and Labeo umbratus from the Olifants and Klein Olifants River, Mpumalanga, South Africa: zinc, copper, manganese, lead, chromium, nickel, aluminium and iron

L Coetzee, HH Du Preez, JHJ Van Vuren
2002 Water S.A  
The upper catchment of the Olifants River, from its origin near Bethal to its confluence with the Wilge River, north of Witbank, and its 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. The major point sources of pollution in the study area include mines, industries and very importantly, combined sewage purification works that are located alongside
more » ... located alongside the river. In addition to oxidizable material, these sources contain detergents, nutrients and metals. It was therefore necessary to determine the extent to which these activities affect the water quality of the system. The bioaccumulation of zinc (Zn), copper(Cu), manganese (Mn), lead (Pb), chromium (Cr), nickel (Ni), aluminium (Al) and iron (Fe) in the skin, muscle, liver and gill tissues of Clarias gariepinus and Labeo umbratus from the Upper Olifants River and Klein Olifants River was investigated over the period February 1994 to May 1995. The highest concentrations of these metals were found in the gill and liver tissues of both species, with lower concentrations in the skin and muscle tissues. Bioaccumulation patterns were found to vary according to the species of the fish, mainly according to their different feeding habits and the routes of metal uptake. It also varied as a function of the different localities. Accumulation was size specific, with higher concentrations of metals found in smaller fish. 434 Available on website http://www.wrc.org.za thermal power stations in the country are located (six of the eight). These power stations receive imported water, with the Komati-, Hendrina-, Arnot-and Duhva Power Stations receiving water from the Komati system and the Kriel-and Matla Power Stations from the Usutu system. The operating mines in this region comprise of 37 coal, 6 brick, 17 sand, 4 felsite and 7 clay mines. Irrigation is a major water use sector in the upper catchment and at the time of the study, 4 760 ha of land was irrigated. Seven towns are situated in the upper catchment. The Witbank/Middelburg complex is a major industrial area with smaller towns Davel, Kinross, Trichardt, Hendrina and Ogies. Several magisterial districts fall partly inside the catchment boundaries, namely Bethal, Belfast, Ermelo, Highveld Ridge, Middelburg and Witbank. Results Fish size The total lengths of the fish ranged between 40.0 cm and 68.5 cm for C. gariepinus and 43.0 cm and 77.0 cm for L. umbratus, while the mass of the fish was in the range of 0.2 to 2.8 kg for C. gariepinus and 0.8 to 3.5 kg for L. umbratus. Bioaccumulation of Zn, Cu, Mn, Pb, Cr, Ni, Al and Fe in the skin, muscle, liver and gill tissue of C. gariepinus and L. umbratus
doi:10.4314/wsa.v28i4.4917 fatcat:j5gklpfumfgbbjbs54x7hr4rry