Which recommendations should be made regarding the presence of PFAS in sludge from urban or industrial wastewater treatment plants ? To address this question, the High Council for Public Health (HCSP) mobilized its standing working group on water safety, which conducted several hearings. 

The issue of sludge applied to land necessarily requires considering all intentional applications to the soil of materials containing PFAS molecules, and taking total annual surface loading rates into account, when developping land application plans. Consequently, the HCSP has included all fertilizing materials ans soil amendments (MFAS) in its deliberations and recommendations. 

There is currently no international consensus on management values for PFAS in materials applied to land. While a common basis regarding the list of PFAS molecules to be included in regulatory values can be identified, this framework must be adaptable to specific local contexts, incorporating additional PFAS based on their presence, as well as known PFAS precursors where applicable.

The HCSP recommends, in particular:

• Systematically implementing policies to reduce PFAS contamination of wastewater at the source, involving the identification and elimination of the most significant sources of PFAS discharge into urban wastewater collection systems;
• Modifying the lists of molecules to be considered for regulatory sums and monitoring, based on HCSP proposals derived from an analysis of measurement campaign results for PFAS-containing materials, to better reflect their representativeness and occurence;
• Classifying PFAS-containing materials into three categories based on measurement campaign results; the first category corresponds to a sum of the 37 analysed PFAS of less than 100 µg/kg dry matter (DM), a PFOA concentration of less than 5 µg/kg DM, or a PFOS concentration of less than 10 µg/kg, with associated maximum surface flux values.

Land application will be authorized, subject to the protection of drinking water abstraction zones and a total annual input limited to specified flux levels for type 1 and type 2 PFAS-containing materials. For drinking water abstraction catchment areas, it is advisable to limit inputs to materials with total PFAS levels below 2 µg/kg DM. Owners of the affected land must be informed of the PFAS concentration levels found in the materials they use.