Polychlorinated Biphenyls and Hydroxylated Polychlorinated Biphenyls in the Blood of Toothed and Baleen Whales Stranded along Japanese Coastal Waters

In this study, we determined the residue levels and patterns of polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCBs) in the blood from eight species of toothed whales and three species of baleen whales stranded along the Japanese coast during 1999–2007. Pentathrough heptachlorinated congeners were the dominant homolog groups in all cetaceans. In contrast, specific differences in the distribution of dominant OH-PCB isomers and homologs were found among the cetacean species. In the seven species of toothed whales (except sperm whales), the predominant homolog group was OH-penta-PCBs followed by OH-tetra-PCBs and OH-tri-PCBs. The predominant OH-PCB isomers were para-OH-PCBs such as 4OH-CB26, 4′OH-CB25/4′OH-CB26/4OH-CB31, 4OH-CB70, 4′OH-CB72, 4′OH-CB97, 4′OH-CB101/4′OH-CB120, and 4OH-CB107/4′OH-CB108 in toothed whales. In three baleen whales (minke whale, Bryde’s whale, and humpback whale) and in sperm whale (which is a toothed whale), OH-octa-PCB (4OH-CB202) was the predominant homolog group accounting for 40–80% of the total OH-PCB concentrations. These results reveal that the accumulation profiles of OHPCBs in cetacean blood are clearly different from the profiles found in other mammals. This study is the first report to comprehensively document the accumulation profiles of OH-PCBs in cetaceans.