PCBs and chlorinated hydrocarbon insecticide residues in birds and fish from the Wilderness Lakes System, South Africa

Concentrations of DDT and PCB residues were determined in the tissues of fish (9 species) and birds (6 species) collected from the Wilderness Lakes System during 1983. Species included permanent and semi-permanent residents, plus occasional visitors. Mean total DDT residue concentrations were 0.14 and 0.11 ug per g in fish and bird samples respectively. The mean concentration of PCB residues in birds was 0.19 ug per g. No PCB residues were detected in fish. Average total DDT and PCB residue concentrations in bird brain (suggested to be the best tissue for diagnostic determination of lethal contamination) were 0.09 and 0.06 ug per g respectively. Comparison with values reported for fish and birds in other areas of the world indicated that contaminant levels in the Wilderness Lakes System and surrounding regions were low.