By Sano Katsuyuki
With regards to the detection of PFOS and PFAS, organic fluorine compounds hazardous to health, in effluent released from a wastewater treatment facility inside the U.S. Fleet Activities Yokosuka (Yokosuka City), the municipal government of Yokosuka announced on Sept. 30 that the concentration level of organic fluorine compounds detected in a third investigation conducted by the U.S. military was 171 higher than Japan’s provisional target value. The cause of the leak has not been identified yet. Mayor Kamiji Katsuaki demanded the U.S. military immediately suspend the discharge of wastewater and that the Japanese government conduct an on-site investigation.
The city was notified by the government of the results of an investigation that the U.S. military conducted on Aug. 29. [According to the results,] 8,592 nanograms of organic fluorine compounds (combined amount of PFOS and PFAS) were detected at a domestic wastewater discharge point. This topped the provisional target value of 50 nanograms per liter that the Ministry of the Environment sets for potable water. At an industrial wastewater discharge point, 5,450 nanograms per liter were detected. The level was 109 greater than Japan’s provisional target value.
The U.S. military conducted an investigation in May and a second one in July following the discovery of foam at a wastewater treatment facility. While the two investigations show that 112 nanograms of organic fluorine compounds per liter were detected, the contamination level detected in the third investigation was conspicuously high. The U.S. military has explained to the Japanese government as well as the municipal office that it is taking steps including the removal of sludge inside the facility every day and has continued to discharge the wastewater into the sea.
“The U.S. military has explained that it is conducting an investigation in a sincere manner and removed sludge from the facility, but look at what happens,” Mayor Kamiji said to the central government official who oversees such issues. “We cannot help feeling anger and we have no trust in the U.S. military per se.” He called for an on-site investigation by the government based on the Japan-U.S. Status of Forces agreement and demanded “the suspension of wastewater discharge.”
The U.S. military has expressed reluctance to suspend the discharge of wastewater as this involves the suspension of water services and of maintenance work at wastewater storage facilities inside bases. On Sept. 30, the U.S. military explained to the Japanese government that it will perform construction work to install filters that use granular active carbon to absorb organic fluorine substances in effluents.
PFOS and PFAS have been also detected near Camp Zama (Zama City and Sagamihara City) and near U.S. military bases in Okinawa. (Abridged)