Abstract
o clarify the levels of organochlorine compounds (OCs) and the metabolism of OCs in the body of Steller sea lion Eumetopias jubatus migrating along the coast of Hokkaido, OCs in the sea lion's blubbers for each age, sex and reproductive status were determined by gas chromatography linked to ion trap mass spectrometer. In sea lions, the compounds accumulated in the highest concentrations are DDT and its metabolites (DDTs) suggesting these animals are still exposed to DDTs from the surrounding land. The levels of DDTs and polychlorinated biphenyls (PCBs) in sea lions may cause small effects such as the induction of drug metabolizing enzymes. The concentrations of DDTs, PCBs, hexachlorocyclohexanes and chlordanes in the old female sea lions were lower than those in the males and young females. This is most likely due to the loss of these compounds during nursing. In addition, the concentrations of each compound differed in the degree of difference between the young and the old females. This result may reflect ecological and physiological difference between the young and the old females. The proportions of tetrachlorinated biphenyl concentrations with vicinal hydrogen atoms in para- and meta- positions to total tetrachlorinated biphenyl concentrations were found to be higher in older animals implying low “phenobarbital inducible type” enzyme activity.
