Derivation of Provisional Drinking Water Tolerance Values for Several PFAS Not Included in the Austrian Drinking Water Regulation.

Per- and polyfluorinated alkyl substances (PFAS) comprise a wide range of industrial chemicals that are currently being evaluated worldwide for their toxic and bioaccumulative properties. Some of these chemicals are already subject to restrictions. The Austrian Drinking Water Regulation (Trinkwasserverordnung, BGBl. II Nr. 304/2001, consolidated version of 16.05.2024) sets a limit of 0.1 μg/L for the sum of 20 PFAS in drinking water from 12 January 2026 as prescribed by Directive (EU) 2020/2184 [1]. However, a large number of PFAS are not covered by this Directive. For some of these compounds, provisional drinking water tolerance values for both adults and infants have been derived in this work. Toxicological assessments and drinking water guideline values derived by other authorities as well as scientific studies were used for this purpose. These provisional tolerance values were compared with the occurrence data of Austrian drinking water and groundwater, as were the health-based guidance values (HBGVs) with the estimated exposure. The tolerance values for adults were not exceeded; however, some measurements for GenX were above the derived provisional tolerance values for infants. The estimated exposures based on the concentrations of PFAS in ground or drinking water did not exceed the HBGVs, yet for infants, the highest levels reached 45 % of the HBGV in the case of GenX. While no immediate health risks are to be anticipated, it is important to ensure that concentrations of PFAS do not increase further.