The Japanese government has released the results of the first nationwide survey of the levels of certain types of PFAS in tap water. Some of these chemicals are said to be potentially harmful.

PFAS are a group of organic fluorine compounds, including PFOS, or perfluorooctanesulfonic acid, and PFOA, or perfluorooctanoic acid. PFOS and PFOA are considered potentially harmful. The government currently sets a provisional target for the two chemicals at a total 50 nanograms per liter for tap water.

The government asked local governments and water utilities to report on whether they have conducted tap water tests for PFAS between the fiscal 2020 and 2024. It also asked them to report on the maximum levels of the chemicals if detected.

The results showed that cases of contamination beyond the target were found in 14 of a total of 3,755 water treatment facilities from fiscal 2020 to 2023. In one case, 1,400 nanograms of PFAS per liter, or 28 times the target, were detected in the town of Kibichuo in Okayama Prefecture, western Japan, in fiscal 2022.

All 14 facilities have found alternative water sources and taken other measures and have not since reported PFAS levels exceeding the target.

The results also showed that all of the 1,745 facilities where tests were conducted this fiscal year reported PFAS levels below the target.

However, the results showed that PFAS with levels above 25 nanograms per liter, or half the target, were still detected at 30 facilities.

It is still not known how the chemicals are entered the water.

In Japan, 1,528 water treatment facilities, or about 40 percent of the total, have not yet carried out tests or reported the results. Many of them are small-scale facilities.

The government is considering whether to upgrade the provisional target to a water quality standard which could mandate tests and improvements on water providers.