EPA Publishes Draft Risk Assessment for PFAS in Biosolids

On January 14, 2025, released its Draft Sewage Sludge (biosolids) Risk Assessment for PFOA and PFOS. EPA uses the term “biosolids” to mean sewage sludge that has been treated to meet the Clean Water Act (CWA) requirements and is intended to be applied to land as a soil amendment or fertilizer. This assessment estimates potential human exposures and risks for 1) people living on or near sites where sewage sludge has been disposed or applied on land, or 2) for people that primarily rely on their products (e.g., food crops, animal products, drinking water). The draft risk calculations are not conservative estimates and do not account from multiple pathways, multiple sources of exposure, and multiple PFAS, where the estimates would be greater than presented in this assessment. This assessment is not a regulation and is not EPA guidance.

Based on modeling, EPA found that human health risks may exceed acceptable thresholds for some pasture farm, food crop farm, and reclamation scenarios when land-applied sewage sludge contains 1 part per billion (ppb) of PFOA or PFOS. EPA also found that there may be human health risks associated with drinking contaminated groundwater sourced near a surface disposal site when sewage sludge containing 1 ppb of PFOA or sewage sludge containing 4 to 5 ppb of PFOS is disposed in an unlined or clay-lined surface disposal unit. In addition, EPA provides a qualitative description of the potential risks to communities living near a sewage sludge incinerator (SSI).

For more information and to view the fact sheets, visit EPA’s website.