Organochlorine pesticides and PCBs in the east ice harp seal (Phoca groenlandica) population

Blubber samples from the Eastern harp seal (Phoca groenlandica) population were obtained during the moulting season in the Russian sector outside of the White Sea, in April and May 1993. Subcutaneous blubber of adult males and females, and juveniles of both sexes was sampled. The following organochlorines were determined: the industrial chemicals PCBs (polychlorinated biphenyls; 21 individual PCB congeners) and HCB (hexachlorobenzene); and the organochlorine pesticides DDT (dichlorodiphenyltrichloroethane); ΣHCH (sum of hexachlorocyclohexane isomers; α-, β- and γ-HCH); and ΣCHL (sum of chlordane metabolites; oxy chlor done, cis-chlordane and trans-nonachlor). A total of 16 PCB congeners, the p,p′-DDT metabolites, and all the pesticides, except γ-HCH, were detected in all animals. The concentrations of ΣPCB (sum of concentrations of 21 PCB congeners) and ΣDDT (sum of concentrations of p,p′-DDT, p,p′-DDE, p,p′-DDD, o,p′-DDT and o,p′-DDD) ranged from 0.8–9.8 and 0.6–7.9 μg g−1 lipid weight, respectively. The median concentrations of HCB, the chlordane metabolites oxychlordane, cis-chlordane and trans-nonachlor, and the HCH isomers were all < 1 μg g−1 lipid weight. When comparing two adult male groups caught early and late in the moulting period, significantly higher HCB levels were found in the latter and leanest group. Although not statistically significant, the same trend was observed in the case of ΣPCB, ΣDDT, ΣCHL and ΣHCH. There is probably a differentiated relative release of organochlorines from the blubber reservoir during the moult in adult males. Significantly higher concentrations of the three major pollutants (ΣPCB, ΣDDT and ΣCHL) were found in adults as compared to the juveniles, while no such relations were found for ΣHCH or ΣHCB. Although the concentrations of ΣPCB, ΣDDT, ΣCHL and ΣHCH in blubber of different harp seal groups were not significantly different with respect to sex, a multiple regression analysis including LMD-index, sex and age indicated that there were lower concentrations of PCB, DDT, CHL and ΣHCH in adult female seals compared to males and juveniles.