Hazardous levels of toxic chemicals like those used at a U.S. military base in Okinawa Prefecture turned up in rivers and groundwater nationwide, according to the Environment Ministry on June 11.

Two types of organic fluorine compound, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), were found in 37 locations that exceeded safe levels, the ministry said.

Sites of contamination were found in Tokyo and 12 prefectures.

These chemicals were present in firefighting foam that leaked from the U.S. Marine Corps Air Station Futenma in Ginowan, Okinawa Prefecture, in April. The chemicals are also used in other substances.

The ministry's survey, the first of its kind, centered around facilities considered to be a potential source of PFOS and PFOA, such as U.S. bases, airports and chemical company plants in fiscal 2019.

Extremely high levels of the toxic materials were detected in three locations close to U.S. bases in Okinawa Prefecture.

The ministry in May set a provisional target level for the concentration of PFOS and PFOA combined in rivers and underwater at 50 nanograms per liter, after studying the effects of the chemicals on the human body.

The concentration of the chemicals detected in the 37 locations were higher than the target level.

The locations were scattered through Tokyo, Saitama, Chiba, Kanagawa, Aichi, Mie, Kyoto, Osaka, Hyogo, Nara, Fukuoka, Oita and Okinawa prefectures.

The highest concentration, 1,855.6 nanograms per liter, was detected under water in Settsu, Osaka Prefecture, where a chemical manufacturer has a plant nearby.

In seven locations in Okinawa Prefecture, the concentration of the chemicals exceeded the standard.

The chemical concentrations exceeded 1,000 nanograms per liter in a river in the city of Okinawa and water from a spring in Nakagami county, both close to the U.S. Kadena Air Base.

In the city of Ginowan, chemical levels exceeding 1,000 nanograms per liter were found in spring water near the Futenma air base.

The water at sites with excessive concentrations of chemicals is not used for drinking.

However, the ministry asked the local governments concerned to alert the public about the danger of drinking water from these sources.


Locations with high PFOS, PFOA concentrations

*In order of city, type of water, investigation point, concentration

*Provisional target level is 50 nanograms per liter

Saitama Prefecture

Honjo, Motokoyamagawa river, Shinsen bridge, 51.8

Chiba Prefecture

Shiroi, Kanayamaotoshi waterway, Nauchi bridge, 349.2

Kashiwa, Teganuma lake, Shimoteganumachuo, 191.0

Ichihara, Heizogawa river, Ikazuchi bridge, 128.6


Tachikawa, groundwater, 337.2

Tachikawa, groundwater, 67.7

Kunitachi, groundwater, 84.4

Nerima Ward, groundwater, 108.4

Nerima Ward, groundwater, 93.0

Hino, groundwater, 94.1

Fuchu, groundwater, 301.8

Chofu, groundwater, 556.0

Shibuya Ward, groundwater, 154.2

Ota Ward, groundwater, 135.1

Kanagawa Prefecture

Yamato, Hikijigawa river, Fukudaichigo bridge, 213.3

Yamato, Hikijigawa river, Sanno bridge, 248.5

Fujisawa, Hikijigawa, Mutsuai bridge, 110.5

Fujisawa, Hikijigawa, Shimotsuchidana Ohashi bridge, 126.8

Fujisawa, Hikijigawa, Akimoto bridge, 107.0

Fujisawa, Hikijigawa, Fujimi bridge, 91.5

Aichi Prefecture

Nagoya, Arakogawa river, Arakogawa pumping station, 107.7

Mie Prefecture

Yokkaichi, Kaizogawa river, Kaizo bridge, 102.3

Kyoto Prefecture

Yawata, groundwater, 85.3

Osaka Prefecture

Settsu, groundwater, 1,855.6

Hyogo Prefecture

Kobe, Akashigawa river, Tamatsu Ohashi bridge, 145.6

Kobe, Akashigawa river, Josuigenshusuiguchi, 105.4

Kasai, ground water, 73.1

Nara Prefecture

Ikoma, Tomiogawa river, Shiba, 64.4

Fukuoka Prefecture

Chikujo town, Miyanokawa river, Kawajiri bridge, 145.9

Oita Prefecture

Oita, Otozugawa river, Beppo bridge, 142.6

Okinawa Prefecture

Okinawa, Tengangawa river, Motokawa bridge, 475.0

Okinawa, Dakujaku river, Dakujaku river, 1,508.1

Ginowan, spring water, Chunnaga, 1,303.0

Ginowan, spring water, Hiyakaga, 168.8

Ginowan, spring water, Mendakarihiga, 815.3

Nakagami county, spring water, Shiriga, 1,188.0

Nakagami county, spring water, Inga, 63.2