Japan’s 5th expert meeting proposed 50 ng/L combined limit for PFOS/PFOA in water 
On December 24, 2024, Japan held an expert meeting to discuss provisional target values for PFOS and PFOA levels in tap water, as well as provisional guidelines for public water bodies and groundwater quality.
For PFOS and PFOA levels in tap water, the following draft policies were proposed:
- The current water quality target items will be reclassified to water quality standard items.
- The standard value for these substances will be set at 50ng/L as an aggregate value, erring on the side of caution maintaining the current approach used for the existing provisional target values.
- The frequency of water quality testing should be once every three months, consistent with that for organic compound levels in tap water.
- When the water quality target items for PFOS and PFOA are reclassified to water quality standard items, the testing methods for these substances should be incorporated to the relevant public notice.
- These standards will take effect on April 1, 2026.
Regarding the provisional guideline values for PFOS and PFOA in public waters and groundwater, it has been decided to continue evaluating their application within the Basic Principles for Establishing Water Quality Environmental Standards and Other Thresholds, taking the following circumstances into consideration.
- It is necessary to gather knowledge on the release and diffusion of these substances into the environment, and to obtain information on effective and efficient countermeasure technologies through the Project for Demonstration of PFAS Countermeasure Technologies (fiscal year [FY] 2024 supplementary budget).
- While providing local governments with the insight and knowledge obtained via item (1) above, it is necessary to study the effectiveness and feasibility of different countermeasures by type of contamination, and how effective the countermeasures should be in reducing health risks.
- It is also necessary to understand the knowledge on the effects of water pollution on food (characterization of transfer from water/soil to agricultural/fishery products, content levels of PFOS in foodstuffs.).
PFAS other than PFOS and PFOA
Since FY2021, Perfluorohexanesulfonic acid (PFHxS) has been designated as an item requiring consideration (no target value set), and some water utilities have been testing for PFHxS. However, knowledge on risk management measures for PFHxS remains insufficient, and according to the evaluation report by the Food Safety Commission of the Cabinet Office, establishing an index value is currently deemed difficult.
For PFASs, it is considered possible to measure multiple PFASs simultaneously by liquid chromatography-mass spectrometry. In September 2022, WHO published a draft background document for public review titled “PFOS and PFOA in Drinking Water” as a preparation for establishing WHO Guidelines for Drinking-water Quality. The document proposes to consider approximately 30 PFAS-related substances that can be measured using currently available methods as candidate substances, and among these, substances with certain levels detected are proposed to be designated as items requiring consideration as PFAS compounds.
Related URLs
- Revised Policy on Handling of PFOS and PFOA Levels in Tap Water (Draft)
https://www.env.go.jp/content/000276966.pdf - Handling of PFOS and PFOA (Provisional) in Public Waters and Groundwater
https://www.env.go.jp/content/000276973.pdf
