Read the full article by Yuji Moronaga, Kei Fujiyama and Ayako Suzuki (The Asahi Shimbun)

“High levels of harmful organic chemicals were detected in a well in the vicinity of Yokota Air Base, and Japanese authorities suspect the contamination may be due to activity at the U.S. military facility in western Tokyo.

The Tokyo metropolitan government noted that the contamination was about 19 times the level set by a U.S. drinking water health advisory.

Officials asked the Defense Ministry to contact U.S. military authorities to ascertain the levels of such chemicals in groundwater within the air base, but as yet has received no response.

Checks for the presence of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) were conducted after Jon Mitchell, a British journalist working in Japan, filed a report in December 2018 about the leakage of firefighting foam from a storage tank at Yokota Air Base in 2012.

Mitchell used the U.S. Freedom of Information Act to obtain documents that included reports of past leakages of various chemicals not only at Yokota, but also at U.S. facilities in Okinawa Prefecture and elsewhere.

Four wells in the vicinity of Yokota Air Base were monitored for levels of PFOS and PFOA. Japan has banned the production, importation and use of PFOS since 2010. The decision came a year after PFOS was included in the Stockholm Convention on Persistent Organic Pollutants. The convention added PFOA to its list in 2019, and the government is seeking to extend its ban to PFOA this year.

Metropolitan government officials said they were unable to conclude that the well water outside the Yokota facility was contaminated by chemicals in the base, given the complicated nature of the underground structure.

Their efforts to get U.S. military officials to divulge the state of water quality within the base as well as explain the use of firefighting foam went nowhere as U.S. authorities have not cooperated with such requests…

According to metropolitan government officials, the well with high levels of organic chemicals was not being used as a source for drinking water at the time of the detection.

A drinking water health advisory issued by the U.S. Environmental Protection Agency limits the combined presence of PFOS and PFOA to 70 nanograms per liter of water…

The Environment Ministry is planning to establish its own guidelines for the two organic chemical groups this spring.

Of the four wells checked, one in Tachikawa, also in western Tokyo, had a combined total of 1,340 nanograms of the two chemicals.

A well in Musashi-Murayama, which is also in western Tokyo, was found to contain a total of 143 nanograms of PFOS and PFOA…”