PFAS levels found to exceed gov't cap in 22 of Japan's 47 prefectures

The Mainichi

26-04-2025

TOKYO (Kyodo) -- Potentially harmful PFAS chemicals have been detected at high levels in rivers and groundwater across 22 of Japan's 47 prefectures, a government survey conducted in fiscal 2023 showed Friday.
The survey, which covered approximately 2,000 sites in 39 prefectures, found that PFAS levels exceeded the government's provisional cap of 50 nanograms per liter in 242 locations. The highest level was detected in groundwater in Settsu, Osaka Prefecture, at 26,000 nanograms per liter, or 520 times the upper target.
PFAS is a general term for a group of over 10,000 artificial chemicals that include PFOS, or perfluorooctanesulfonic acid, and PFOA, or perfluorooctanoic acid. They are used in various products, such as frying pan coatings and water-repellent clothing.
There is currently no concrete evidence of adverse health impacts from PFAS, although some researchers have warned of potential effects, including an increased risk of cancer.
Of the 242 sites where high PFAS levels were found, 42 sites across nine prefectures showed levels above the provisional cap for the first time and 97 locations had previously exceeded the cap and remain under monitoring, while 103 sites were those close to locations which exceeded the cap in past surveys and monitored to identify the extent of past contamination.
PFAS contamination is frequently detected near factories, U.S. military bases, and Japan Self-Defense Forces facilities. The Environment Ministry, however, has not disclosed the specific testing sites.
Local governments have identified the source of contamination in only four cases, including Kibichuo, a town in Okayama Prefecture, where disposed activated carbon was determined to be the cause.
At sites where the polluted water had been used for drinking, authorities have already taken measures such as switching water sources or restricting consumption.
Other areas where high levels were detected included groundwater in Higashihiroshima, Hiroshima Prefecture, at 15,000 nanograms per liter, a river in Ayabe, Kyoto Prefecture, at 4,600 nanograms, and groundwater in Ginowan, Okinawa Prefecture, at 2,200 nanograms.
The data was compiled based on studies conducted by the ministry as well as local government-led investigations. Eight prefectures did not provide responses to the voluntary survey.
While high PFAS levels were detected in 111 sites across 16 prefectures in the previous study in fiscal 2022, the ministry noted that direct comparison was difficult due to differing survey conditions.