Expedite Surveys to Find Sources of Discharge, Purification Efforts

Hazardous chemicals have been detected at high levels in rivers and groundwater across Japan. The government must not underestimate the situation; it must expedite such measures as conducting surveys to identify the sources of the discharge and making efforts for purification.

According to a water quality survey conducted by the Environment Ministry in fiscal 2021, concentrations of per- and polyfluoroalkyl substances (PFAS), which are feared to be carcinogenic, exceeded national targets at a total of 81 sites in Tokyo and 12 prefectures, including Osaka, Kanagawa and Oita prefectures.

PFAS chemicals, which repel water and oil and resist heat, are used as components in frying pan coatings and foam fire extinguishing agents. They are also used in semiconductor manufacturing, among other things.

There are various types of PFAS, and substances called perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are seen as especially problematic in terms of toxicity. Introduced into the body in large quantities, they may cause cancer and hyperlipidemia.

The government banned the manufacture and import of these two substances by the end of 2021. It has set a maximum of 50 nanograms per liter as a target for the amount in drinking water that does not affect health.

Although no health hazards have been confirmed so far in Japan, PFAS are hardly broken down naturally and remain in water and the ground for a long period of time. It is important to continue to examine the effects on health.

PFAS leaks have been confirmed at locations including airports and at a factory of a manufacturer of air conditioning equipment, but the leakage from U.S. military bases in Japan has been a particular problem.

According to the Defense Ministry, foam fire extinguishing agents containing PFAS leaked at the U.S. Yokota Air Base on a total of three occasions in 2010 and 2012. Leakage was also confirmed at the Futenma Air Station in Okinawa Prefecture in 2020 as well as the Yokosuka and Atsugi bases in 2022.

The Environment Ministry conducted on-site inspections at the Yokosuka and Atsugi bases in accordance with a supplementary agreement on the environment to the Japan-U.S. Status of Forces Agreement and confirmed that there were no problems with the purification process used by the U.S. military following the leakage.

However, the U.S. side did not initially notify Japan of the leakage at the Yokota base. As for the surveys by the Okinawa prefectural government, the release of the survey results was delayed because the U.S. side did not agree to the move. Residents in the vicinity of both facilities were concerned about possible health hazards, and blood tests were conducted among groups of people as a result.

The stationing of U.S. forces in Japan is the foundation of the Japan-U.S. alliance, and the understanding of local residents is essential to the operation. It is hoped that U.S. forces will sincerely respond to consultations with the Japanese side on the matter and cooperate with surveys.

According to the Environment Ministry, foam fire extinguishing agents in large quantities remain in Self-Defense Forces facilities and fire departments, among other places, across Japan. The government should secure funding and actively conduct high-temperature incinerations and purify groundwater and other resources.

(From The Yomiuri Shimbun, July 31, 2023)