Chlorinated hydrocarbons and heavy metal in crocodile eggs from Zimbabwe

Crocodile eggs in 1981-82, from several localities in Zimbabwe were analysed fro residues of chlorinated hydrocarbon pesticides and for Hg, Se, Cd, Pb and Zn. All eggs analysed showed residues of DDT and its metabolites. Total DDT+DDE+DDD levels varied from 3.14 mg/kg to 25.91 mg/kg on a dry-mass basis, and these levels were related to the type of land use in the areas from which the eggs were collected. Residues of the isomer of HCH were detected at low levels in most samples, and toxaphene was recorded in eggs from cattle ranching areas. Polychlorinated biphenyls were recorded in all samples, but only in industrialized areas were the levels in excess of 1 mg/kg on a dry-mass basis. Levels of Hg were higher in eggs from the Sengwa river than in eggs from elsewhere in Zimbabwe, and Pb levels ranged from 1.250 mg/kg to 10.21 mg/kg on a dry-mass basis, being highest in eggs from where the bedrock was granite. Levels of Se, Cd, and Zn did not show consistent variation in accordance with the area where the eggs were collected.