A further investigation into the bioaccumulation of lead and zinc in the organs and tissues of the African sharptooth catfish, Clarias gariepinus from two localities in the Olifants River, Kruger National Park

The bioaccumulation of lead and zinc in the gills, liver, muscle and skin of Ciarias gariepimis from two locations, Mamba and Balule, on the Olifants River within the Kruger National Park is reported here. Over a one year period (1994), four surveys (February, May, July and November) were undertaken. Atomic absorption spectrophotometry was used to determine the concentrations of both metals in the tissues. The gills were the major route of uptake, with the liver accumulating high lead and zinc concentrations. The concentration of metals in the fish found at Mamba and Balule were found to be significantly different from each other. However, it could not be established at which location the greatest amount of bioaccumulation had taken place. The influences of temperature, alkalinity, salinity and pH on metal toxicity, bioavailability and bioaccumulation rates are discussed in detail. It is imperative that pollution levels in the Olifants River and its effect on fish is continually monitored and captured, so as to maintain and conserve this river and the biota dependant on it.