As part of the agency’s efforts to regulate per- and polyfluoroalkyl substances (PFAS), the EPA released a draft risk assessment for use of sewage sludge that is land-applied as a soil conditioner or fertilizer. Public comments on the assessment are due by March 17, 2025. About 31% of such material is treated to become biosolids applied to agricultural lands.
The EPA performed modeling which suggests that land application of biosolids that contain detectable PFAS “could result in human health risks exceeding the agency’s acceptable thresholds for cancer and non-cancer effects.” Even at this low level (1 ppb) the models showed excess risk via consumption of drinking water, fish, beef, milk, eggs, and certain fruits and vegetables. In some circumstances, a single application of biosolids could result in risks that exceed acceptable levels. The risks increase with the amount of a person’s diet that comes from farms which use PFAS-contaminated biosolids, so farm families would be particularly affected. The assessment also identified risks to drinking water from unlined and clay-lined surface disposal sites.
After it receives public comment, the EPA will finalize its risk assessment and conduct additional surveys and studies. The agency stated it might propose restrictions on land application of PFAS-contaminated biosolids under its authority in section 405 of the Clean Water Act.. Maine, Connecticut, and Michigan have already restricted land application of biosolids, and several other states are in the process of regulation.
Discovery of PFAS contamination on farms has led to Clean Water Act litigation, including some filed by agricultural producers against PFAS manufacturers and suppliers. Another suit has been brought by farmers who seek to accelerate the agency’s regulatory action in order to receive clear guidance on acceptance and use of biosolids from wastewater treaters. The EPA also designated PFAS as a hazardous substance under the Superfund law in May 2024, which means that parties who engage in cleanup efforts might seek reimbursement for those costs via future litigation.
