CONCENTRATION OF CD, CU, NI, PB, ZN AND MN IN BREAM, OREOCHROMIS MACRUCHIR, DURING THE 1996 MASS FISH DEATHS IN LAKE CHIVERO, ZIMBABWE

The results of analysis for selected toxic heavy metals of samples of dead bream, Oreochromis macruchir, collected during the mass fish deat hs in Lake Chivero, Zimbabwe, in March-April 1996 are presented. When compared to results for bream samples collected in April-August 1994, the 1996 results show that levels of Cd, Cu, Ni, Pb, and Zn in the mus cle of the dead bream had risen by factors of 5, 77, 15, 384, and 17 r espectively. Analysis of the lake water confirmed the pollution of the lake by heavy metals, especially Cd, Ni and Pb, at the time of the fi shkill. Possible sources of the heavy metal pollution are discussed.