By Fukui Maho and Kuniyoshi Mika
The U.S. military in Okinawa plans to release wastewater contaminated with organic fluorides such as perfluorooctanesulfonic acid (PFOS), which are suspected of being carcinogenic, into sewers outside its facility, sources informed The Asahi Shimbun. The U.S. military explained that the concentration of hazardous substances in the wastewater will be “reduced to a level equivalent to that in drinking water before release into sewers.” An expert points out that “there are safety concerns, as the amount of wastewater to be discharged is not known.”
Okinawa Prefecture made an inquiry to the Ministry of Defense Okinawa Defense Bureau to confirm the plan after local media reported that the U.S. had approached the Japanese side about the release of the wastewater. The U.S. Marine Corps reportedly plans to discharge wastewater outside Marine Corps Air Station Futenma (Ginowan City).
According to relevant authorities in the prefecture and Ginowan city governments, the U.S. side said that the wastewater had been treated by local contractors up to now, but that it would like to discharge the wastewater into sewers this time due to the cost. The U.S. reportedly explained that the concentration of the contaminants in the water would be reduced to a level lower than the benchmark value of Japanese water quality regulations. The amount of wastewater to be discharged was reportedly not disclosed. The prefecture is calling for the discharge to be postponed until safety is confirmed.
Prefectural sewage facilities do not lower the concentration of PFOS and other such hazardous substances, according to the prefecture. There is a strong likelihood that such substances would flow into the ocean if water containing these substances is discharged into sewers. The prefecture and the city do not have ordinances related to such matters and blocking the plan is seen to be difficult.
Kyoto University Associate Professor Harada Koji (health and environmental sciences) notes that “the environmental impact will depend on the amount of discharge.” Harada says that “the Japanese government should ask the U.S. to release information such as the total amount of wastewater,” and that “it is necessary to conduct a survey on whether the plan will affect the environment.”