Forever Chemicals : EPA warns of health and environmental risks of PFAS in biosolids

On January 14, 2025, the U.S. Environmental Protection Agency (EPA) released a draft risk assessment addressing the presence of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in sewage sludge, commonly referred to as biosolids. This assessment underscores potential health risks associated with the land application, surface disposal, or incineration of biosolids containing these persistent chemicals.

PFOA and PFOS are part of the per- and polyfluoroalkyl substances (PFAS) family, often labeled as "forever chemicals" due to their resistance to environmental degradation. These compounds have been linked to various health issues, including certain cancers, liver damage, and developmental challenges in children. The EPA's draft assessment specifically highlights elevated risks for individuals residing near or consuming products from farms utilizing such sludge.

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The role of biosolids in waste management and agriculture cannot be overlooked. Derived from treated sewage sludge, biosolids are often repurposed as fertilizers or used in land reclamation due to their nutrient-rich content. However, their application introduces risks when contaminated with PFAS like PFOA and PFOS. The draft risk assessment evaluates three main biosolid management pathways:

1. Land Application: The use of biosolids as agricultural fertilizers.
2. Surface Disposal: The long-term storage or disposal of biosolids in designated areas.
3. Incineration: Burning biosolids to reduce waste volume and generate energy, which may release PFAS into the air.

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The assessment highlights several pathways through which humans could be exposed to PFOA and PFOS:

• Dietary Exposure: Consuming food grown in soils treated with contaminated biosolids.
• Drinking Water: PFAS leaching into groundwater or surface water sources.
• Airborne Exposure: Inhalation of particulates or fumes from biosolid-incineration facilities.
• Soil and Dust Ingestion: Direct exposure to contaminated soils or dust in areas where biosolids have been applied.

Using toxicity reference values (TRVs) established from studies on these chemicals, the draft ties exposure to potential health effects such as cancer, developmental issues in infants, liver dysfunction, and immune system suppression. These findings point to the importance of stricter regulations and monitoring of biosolid use.

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The EPA's draft also underscores the environmental risks of PFAS, given their persistence and mobility. Key concerns include:

• Water Contamination: Runoff from biosolid-treated fields can introduce PFAS into water bodies.
• Soil Contamination: Persistent accumulation of PFAS in soils could affect long-term agricultural productivity.
• Bioaccumulation: PFAS entering the food chain may pose extended risks to both wildlife and humans.

The release of this draft aligns with the broader environmental objectives of the Biden administration, which prioritizes addressing climate change and reducing hazardous substance exposure. Early in his term, President Biden issued an executive order emphasizing urgent climate action, alongside the creation of the National Climate Task Force. This draft complements ongoing efforts, including:

• The establishment of federal drinking water standards for PFAS.
• Proposed rulemaking to designate PFOA and PFOS as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
• Research into PFAS destruction technologies such as thermal treatment and chemical degradation.

Future regulations based on this assessment could lead to stricter limits on PFAS concentrations in biosolids, more rigorous treatment standards, and enhanced source-reduction strategies at the municipal level.

The EPA’s commitment to transparency is evident in its call for public feedback. Stakeholders, including scientists, municipal agencies, environmental advocates, and the general public, are encouraged to submit comments on the draft until March 17, 2025. The final assessment will use this input to shape policies that mitigate PFAS risks while addressing practical biosolid management challenges.