EPA Releases Draft Risk Assessment to Advance Scientific Understanding of PFOA and PFOS in Biosolids

By: U.S. EPA

Jan 14, 2025

The U.S. Environmental Protection Agency (EPA) has released a draft risk assessment evaluating the potential health risks associated with toxic per- and polyfluoroalkyl substances (PFAS) in biosolids, commonly known as sewage sludge. The findings indicate possible health risks from exposure to two prominent PFAS chemicals, PFOA and PFOS, across all three primary methods of biosolid disposal: land application, landfill surface disposal, and incineration. While the assessment is still under review, it aims to provide federal and state agencies, wastewater systems, farmers, and other stakeholders with critical insights to mitigate PFAS exposure and protect public health. According to EPA Acting Administrator Jane Nishida, the draft represents an important step in advancing scientific understanding and informing future regulatory actions.

Biosolids, produced during wastewater treatment, are often reused as soil conditioners or fertilizers due to their nutrient content. However, the EPA’s draft assessment reveals that biosolids containing as little as one part per billion (ppb) of PFOA or PFOS can pose risks that exceed acceptable thresholds, particularly in scenarios involving repeated applications over decades or disposal in inadequately lined landfills. While risks from incineration could not be quantified due to data gaps, the analysis shows that the level of PFAS in biosolids directly correlates with the potential health risks. Despite this, EPA notes that biosolids account for less than 1% of fertilized agricultural land annually in the U.S., and the broader food supply appears unaffected. However, localized contamination “hot spots” may require targeted interventions to safeguard farmers and nearby communities.

Under its PFAS Strategic Roadmap, the EPA has made significant strides in regulating these “forever chemicals,” including setting new drinking water standards and classifying PFOA and PFOS as hazardous substances. To further address PFAS in biosolids, the EPA is considering additional measures under the Clean Water Act and collaborating with states to enhance monitoring and risk management. This assessment underscores the need for proactive policies to reduce PFAS at their source and highlights the importance of continued scientific research and cross-agency collaboration to protect public health.

For additional information, see the original article.