Concentration and characteristics of polychlorinated biphenyls in the sediments of sea and river in Nagasaki Prefecture, Japan

Environmental pollution with polychlorinated biphenyls (PCBs) continues in Japan due to their high persistency, although their manufacture and use have already been prohibited. In this study, PCBs in sediments at 67 sites in Nagasaki Prefecture were determined by GC-MS, and their profiles were compared with those of commercial PCBs (Kanechlor KC300-600). The concentrations of PCBs in the sediments of sea and river areas in Nagasaki Prefecture were found to be up to 2.5 and 0.035 μg/g, respectively. Higher concentrations of PCBs in the sediments of the sea compared to those from river were observed (except area D vs N). The profile of PCB homologues in the sediments of the sea areas was similar to that of Kanechlor KC600, whereas the profile of PCB homologues in the river sediments was similar to that of Kanechlor KC500. Moreover, the source contribution was estimated by a chemical mass balance (CMB) method using the composition ratio of major congeners of Kanechlor. As a result, it was found that the contributions of KC600 and KC500 were higher in sea sediments (ca. 60%) than in river sediments (ca 50%)