Tissue concentrations of organochlorine compounds in common seals from the coast of Northern Ireland

Abstract

An epizootic of morbillivirus infection killed several hundred common seals ( Phoca vitulina) along the coast of Northern Ireland in 1988. Many dead and moribund seals were submitted to the Department of Agriculture for Northern Ireland, Veterinary Research Laboratories for necropsy. Samples of blubber, liver and kidney were collected from these animals ( n = 55) for analysis for a wide range of organochlorine pesticides and also total polychlorinated biphenyls (PCBs). The organochlorines found in highest concentrations in blubber were PCBs which were detected in all samples (mean, 26 μg g −1 wet wt). ΣDDT (mean, 2.63 μg g −1 wet wt) and chlordane (mean, 0.22 μg g −1 wet wt) were also present in all samples. Heptachlor including heptachlor epoxide (mean, 0.13 μg g −1 wet wt) was present in over 935 of samples. Seventy-four percent of samples contained αHCH (mean, 0.035 μg g −1 wet wt), 50% contained βHCH (mean, 0.026 μg g −1 wet wt) while γHCH (mean, 0.012 μg g −1 wet wt) was detected in 46% of samples. The organochlorine concentrations found in this study are at the lower end of the range previously reported for European common seals.