CONCENTRATIONS OF HEAVY METALS (Cd, Cu, Pb, Ni & Zn) AND ORGANOCHLORINE CONTAMINANTS (PCBs, DDT, DDE & DDD) IN THE BLUBBER OF CAPE FUR SEALS ARCTOCEPHALUS PUSILLUS PUSILLUS OFF THE EASTERN CAPE COAST OF SOUTH AFRICA

The concentration of heavy metals (Cd, Cu, Pb, Ni and Zn) and organochlorine contaminants (PCBs, DDT, DDE and DDD) in the blubber of 12 adult male Cape fur seals, Arctocephalus pusillus pusillus, inadvertently caught in trawl nets off the Eastern Cape coast of South Africa during commercial fishing operations between May 1993 and October 1994, was investigated. The median and range of concentrations for each metal were, in μg/g wet weight: Cd, 0.4 (<0.04-0.53); Cu, 2.6 (2.17-7.43); Pb, 0.7 (0.54-0.99); Ni, 17.7 (9.39-23.18) and Zn, 11.5 (3.14-16.65). Dry weights were: Cd, 0.5 (<0.04-0.59); Cu, 2.9 (2.47-8.45); Pb, 0.6 (0.54-1.14); Ni, 17.0 (10.79-28.22) and Zn, 12.8 (3.61-20.26). Concentrations of Cd, Pb and Zn were in the limits of reported values; however Cu and Ni levels were considerably higher. There is no evidence that the elevated levels of Cu and Ni reported in this study would pose a serious threat to the health of individual animals; however, high concentrations of these metals may be sufficient to result in some additional stress to animals when they mobilise their lipid reserves during illness or starvation. Ni and Cd concentrations appeared to increase with age; however, small sample size prevented statistical analysis. Concentrations of organochlorines (μg/g wet weight) were below the limit of detection.