Current Status and Response to PCB/DDT Contamination in Tokyo Bay and Osaka Bay - 2020s

Current Status and Response to PCB/DDT Contamination in Tokyo Bay and Osaka Bay - 2020s

In the 2020s, marine pollution from polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) remains a serious problem in Tokyo Bay and Osaka Bay in Japan. These toxic substances, which were banned in the 1970s, have accumulated in the ocean as industrial waste over the years. In particular, in some areas of Tokyo Bay, PCB concentrations exceeding 100 nanograms/liter were identified in a 2020 survey and continue to far exceed environmental standards.

Similarly, PCBs and DDT have accumulated in bottom sediments in Osaka Bay, with high concentrations of PCBs detected in some sediments in the 2021 survey. The effects of past industrial activities in the Hanshin Industrial Zone remain, and contamination is still ongoing. PCB contamination has also been confirmed in Kushiro Marsh, and there are concerns about the impact on waterfowl and fish.

The main cause of this contamination is that PCBs and DDT used in the past were not properly treated and leaked into the ocean as waste. Particularly in Japan, PCBs are contained in electrical equipment and paints manufactured before the 1970s, and these wastes have flowed into oceans and rivers. Furthermore, past cases of contamination, such as the Kanemi oil spill incident, are also relevant and may still be having an impact.

Japan Environmental Safety Corporation (JESCO) is playing a central role in promoting the disposal of PCB waste throughout Japan, but there are many issues to be addressed before the 2027 disposal deadline. In particular, small and medium-sized enterprises and local governments are not making progress in treatment, and the limitation of treatment capacity is becoming an issue.

Companies such as Hitachi, Ltd. and Kawasaki Heavy Industries, Ltd. have developed technologies to render PCBs and other hazardous substances harmless, contributing to pollution control measures in Japan and abroad, but monitoring systems remain inadequate in some areas.

In the future, the Japanese government will have an urgent need to address new contaminants such as perfluoroalkyl compounds (PFAS) in parallel with the treatment of PCB waste. International cooperation is required to provide technology and strengthen policies to prevent environmental pollution throughout the Asian region.