Polychlorinated biphenyl pollution from shipbuilding in Nagasaki Bay, Japan

Polychlorinated biphenyl (PCB) pollution from shipbuilding in Nagasaki Bay, Japan, was discussed by determining PCB concentrations in sediment, in water, and in biological samples. PCBs were detected in all samples, in which much higher concentrations, more than 10 micrograms/g, were found in three sediment samples where located near the shipyard drains. In general, PCB concentrations in sediments and organisms tended to increase toward the inner part of this bay. PCB isomer and congener compositions in organisms as well as sediments were composed mainly of higher chlorinated biphenyls and almost similar to Kanechlor 500 and 600 products (chlorine content 54 and 60%, respectively) that have been used for ship paints. These results strongly suggest that the shipbuilding is primarily responsible for the PCB pollution in Nagasaki Bay. Bioaccumulation factors of PCBs were different among the organisms according to their trophic levels. This might be a result of the predominant PCB transfer through the food chain in organisms and the discharge of bioaccumulative PCBs as higher chlorinated biphenyls from shipyards. These observations imply that the PCB pollution from shipbuilding would continue for a long time due to the accumulative characteristics of PCBs used for ship paints and the further discharge by scraping the stale paints in shipyards.