The U.S. Environmental Protection Agency (EPA) has issued a draft risk assessment examining the potential human health risks associated with per- and polyfluoroalkyl substances (PFAS) in biosolids, commonly referred to as sewage sludge. The study, released on January 14, 2025, evaluates the impact of PFAS chemicals PFOA and PFOS when sewage sludge is applied to land, disposed of in landfills, or incinerated.
According to the draft findings, exposure to these "forever chemicals" could pose health risks through all three methods of disposal or use. "Once finalized," said EPA Acting Administrator Jane Nishida, "the assessment will help EPA and its partners understand the public health impact of forever chemicals in biosolids and inform any potential future actions to help reduce the risk of exposure."
The report aims to guide federal and state agencies, wastewater systems, farmers, and other stakeholders on protecting people from PFAS exposure while supporting industry. The focus is on populations most likely to be exposed through land application of biosolids or consumption of products from affected areas.
Preliminary findings suggest that human health risks can exceed acceptable thresholds when biosolids containing even minimal amounts of PFOA or PFOS are applied repeatedly over decades. The draft also highlights scenarios where disposal units are inadequately lined. However, due to data gaps, risks related to incineration were not quantified.
The EPA noted that its analysis does not indicate a widespread impact on the general food supply but acknowledged potential "hot spots" where higher levels of contamination may occur. This underscores the importance of further collaboration with affected operations and federal agencies.
By lowering concentrations or reducing applications of contaminated biosolids, risks can be mitigated. Factors such as geography, climate, soil conditions, crop types, and nutrient needs also influence actual risk levels at specific sites.
The draft risk assessment supports proactive policies aimed at controlling PFAS at their source. Under its PFAS Strategic Roadmap initiative, EPA has provided tools for restricting environmental entry and holding polluters accountable.
PFOA and PFOS reach municipal wastewater treatment plants (WWTPs) from various sources including manufacturers using these substances or from consumer products washed down drains.
In line with ongoing efforts under its roadmap strategy—such as setting drinking water standards for PFAS—the agency seeks stakeholder feedback during a 60-day public comment period following publication in the Federal Register. A webinar discussing this topic is scheduled for January 15th at noon ET.
