NOTE ON THE OCCURRENCE OF SELECTED TRACE-METALS AND ORGANIC-COMPOUNDSIN WATER, SEDIMENT AND BIOTA OF THE CROCODILE RIVER, EASTERN TRANSVAAL, SOUTH-AFRICA

Samples of water, sediment and biota (7 species of fish and 2 species of macrophytic plant) were collected at a number of sites on the Croco dile River, E. Transvaal. These samples were analysed for the trace me tals arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), selenium (Se), zinc (Zn), manganese (Mn), aluminium (Al) and iron (Fe ), the pesticides DDT, DDE, DDD, Dieldrin, Heptachlor, Lindane and End osulfan, as well as the polychlorinated biphenyls Arochlor 1254 and Ar ochlor 1260. Acid-extractable concentrations of the detected metals ar e reported. Concentrations of As, Cd, Cu, Hg and Se never exceeded the ir respective detection limits in water samples. All the metals but Cd , Pb and Hg were detected in the sediment samples, and all but Cu, Pb and Hg were detected in muscle tissue of fish. Arsenic, Cu, Zn, Mn, Al and Fe were detected in plant tissue. The detected metals always occu rred at higher concentrations in the roots than in the leaves of the s ampled plants. None of the selected pesticides was detected in the sed iment samples and only p,p-DDE was found in muscle tissue of fish.