| Summary: | Harp seals (Phoca groenlandica) from the Barents Sea were analyzed for blubber levels of polychlorinated biphenyls(PCBs), polychlorinated camphenes (PCCs; toxaphenes), DDT and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexanes(HCHs), and the cyclodiene pesticides, including dieldrin, endrin, and the chlordanes. Also, the hepatic cytochrome P450(CYP) enzyme activities were measured to assess a possible relation between CYP activities and pesticide levels. Furthermore, thebioaccumulation potential and persistency of these compounds were evaluated. PCCs were the dominant contaminants, exceedingthe PCB concentrations. Individual PCC congener levels (Tox 26 and 50) were fourfold greater than those in the Canadian Arcticand 20-fold greater than those in seals from the west coast of Svalbard, suggesting that the Barents Sea is exposed to PCCs by alocal source. The biomagnification factor and the metabolic index were greatest for p,p-DDT, HCB, b-HCH, and the chlordanestrans-nonachlor and U82. The other pesticides showed lesser values, suggesting metabolism. The ethoxyresorufin-O-deethylationactivity (CYP1A) was high and not correlated with any of the pesticides, whereas a high correlation (r2 adjusted . 50%) was foundbetween the PCCs and testosterone 6-b hydroxylation activities (CYP3A). This suggests an induction of CYP3A-like activity byPCC exposure.
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