PCB and DDT Marine Pollution in Japanese Coastal Waters - May 1998

PCB and DDT Marine Pollution in Japanese Coastal Waters - May 1998

A research team from Ehime University conducted a survey in 1998 and found high concentrations of hazardous chemicals such as PCB (Polychlorinated Biphenyl) and DDT (Dichlorodiphenyltrichloroethane) in the bodies of marine mammals (pilot whales and orcas) captured in Japanese coastal waters, particularly around the Seto Inland Sea and off the coast of Kyushu. The fat of orcas contained 400 micrograms of PCB per gram, approximately 4,000 times the concentration found in land animals. Additionally, pilot whales were found to have 200 micrograms of DDT, highlighting the severity of the pollution.

The cause of this pollution has been attributed to improper waste disposal in developing Asian countries, particularly in China and Indonesia. In these countries, electronic devices and pesticides have been improperly discarded, allowing PCBs and DDT to flow into the air, rivers, and oceans. These chemicals are carried by ocean currents such as the Kuroshio Current and accumulate in marine life in Japanese waters, including the Seto Inland Sea and off Kyushu.

Domestically, past use of PCB that has not been properly managed also likely affects the water quality around Tokyo Bay. PCB from electrical equipment and building materials discarded in the 1970s is still a major concern, and improper waste management in Japan has also contributed to this pollution.

In response to this investigation, the Ministry of the Environment has strengthened monitoring of Japanese coastal waters and is working on measures to prevent further expansion of pollution from PCB and DDT.