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Okinawa gov. seeks immediate end to US disposal of possibly carcinogenic water into sewer

Okinawa Gov. Denny Tamaki is seen criticizing the U.S. response over potentially toxic water releases, at an emergency press conference at the Okinawa Prefectural Government building in Naha on Aug. 26, 2021. (Mainichi/Nozomu Takeuchi)

NAHA -- The governor of Okinawa Prefecture has sought an immediate stop to U.S. military disposal of water containing potentially carcinogenic substances into the local public sewage system.

    On Aug. 26, the U.S. Marine Corps in Okinawa announced it has begun to dump into the public sewage system, following water treatment, water containing purportedly carcinogenic organic fluorine compounds including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) kept in water tanks at Marine Corps Air Station Futenma in the city of Ginowan.

    The Okinawa Prefectural Government and the Ginowan Municipal Government have opposed the move. Gov. Denny Tamaki told an emergency press conference, "I am very angry about the U.S.'s one-sided release of the water," and called for an immediate halt.

    The U.S. Marine Corps notified the prefectural government of the release in an email at 9:05 a.m. on Aug. 26 -- 30 minutes before it started. The email also explained that the chemical amounts set for disposal were below the Japanese government-set provisional target values including for tap water, but it didn't specify exactly how much would be released.

    According to explanations provided so far by the U.S. Marine Corps to the prefectural government and other bodies, Marine Corps Air Station Futenma was previously using fire extinguisher foam concentrates containing PFOS in training. The contaminated water produced by these drills was stored in six water tanks at the air station.

    Until now the material had been entrusted to a contractor to incinerate, but due to cost and other factors, in July the Marines approached the national and prefectural governments about dumping the water into the sewage system. The prefectural government asked that the incineration disposal be continued.

    The national government's provisional limit for PFOS and PFOA in ground and tap water is 50 nanograms total (1 nanogram is one-billionth of a gram) per liter.

    Regarding the recent water release, the Marines said the total concentration of both compounds following decontamination was 2.7 nanograms or less per liter, or about 20 times cleaner than the provisional limit. The excluded harmful materials will reportedly be incinerated at a facility outside the prefecture. According to the Ginowan Municipal Government, the water will flow into the sea following sewage processing.

    In April 2020, there was an off-base leak of the fire extinguisher foam near the Futenma air station, and high concentrations of compounds including PFOS were recorded in springs and groundwater in the area.

    Many citizens are concerned by the activity. Ginowan Mayor Masanori Matsugawa has lodged a protest with the Ministry of Defense's Okinawa Defense Bureau and the Ministry of Foreign Affairs Okinawa Liaison Office, calling for the water releases to be suspended.

    (Japanese original by Takayasu Endo and Nozomu Takeuchi, Naha Bureau)

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