2026 Volume 36 Issue Special_Issue Pages s79-s89
Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were designated as “complementary items” in Japan’s drinking water quality management in 2020. A provisional target value of 50 ng/L was set for the combined value of these two substances. Perfluorohexanesulfonic acid (PFHxS) was classified as a “items for further study” in 2021 due to the lack of established toxicity assessments and unclear detection status in tap water, and no target value has been set for it yet. Currently, it has been decided that PFOS and PFOA in tap water will be upgraded to “water quality standards” subject to mandatory testing in April 2026. Further, seven PFASs other than PFHxS have been newly added to the items for further study. The standard analytical method for PFAS in drinking water (the notification method) is notified by the Ministry of the Environment, targeting PFOS, PFOA, and PFHxS. However, with the re-elevation of PFOS and PFOA to the water quality standards, the testing method are currently underway revisions. This review paper explains the trends and challenges in the regulation and testing methods for PFAS in Japan’s drinking water quality management.
