Methyl Sulphone Metabolites of Polychlorinated Biphenyls (PCBs) in Cetaceans from the Irish and the Aegean Seas

The levels of PCBs and PCB methyl sulphone metabolites were determined in the blubber of six species of cetaceans that originated from the Irish Sea and the Aegean Sea (Mediterranean). Burdens ranging from 2.80 to 27.80 μg g−1 (lipid weight) total PCBs and 0.03 to 0.58 μg g−1 (lipid weight) total methyl sulphones were recorded. The highest cetacean methyl sulphone burden (0.58 μg g−1) was in an Irish Sea harbor porpoise (Phocoena phocoena). Methyl sulphone isomer formation capacity, as determined by PCB:MSF ratios, varied considerably between species as follows: harbour porpoise (1:10) > pilot whale (Globicephalus melas), white-sided dolphin (Lagenorhyncus acutus) (1:50) > common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), and striped dolphin (Stenella coerueoalba), (1:100), and was related to interspecific variation in PCB methyl sulphone formation capacity.