EPA’s draft PFAS risk assessment: implications for biosolids management

The U.S. Environmental Protection Agency (EPA) recently released a draft risk assessment (DRA) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in biosolids, prompting discussion across the water sector. In Smart Water Magazine, Carollo’s Wastewater Practice Director, Rashi Gupta, examines the key takeaways from this assessment and its potential impact on utilities managing biosolids.

How the EPA’s Draft Risk Assessment Differs from Past Approaches

Historically, the EPA has used risk assessments to guide regulatory decisions, considering both risk evaluation and management before setting enforceable limits. This DRA follows a different approach. While it does not establish regulatory limits, it raises concerns about potential risks associated with land application of biosolids, particularly for hypothetical “farm families” that consume food and water exclusively from land treated with biosolids. According to Rashi, the absence of a risk management analysis indicates that national regulatory limits are not imminent, but the assessment could still influence future state or local policies.

Rashi emphasizes that the assessment focuses on a limited set of exposure scenarios rather than evaluating risks for the general public. The EPA modeled situations where biosolids containing one part per billion of PFOA and PFOS were applied to farmland once a year for 40 years. Under these assumptions, some modeled scenarios exceeded acceptable health risk thresholds.

Uncertainty for Biosolids in Landfills

The draft assessment could have significant implications for biosolids management strategies. Currently, more than half of biosolids are land-applied, while others are incinerated, landfilled, or managed through other methods. The EPA’s analysis primarily focused on land application, leaving risks associated with incineration and landfilling largely unaddressed. Despite acknowledging potential risks, the DRA did not quantify the impact of biosolids incineration. Similarly, it did not evaluate the risks posed by PFAS-containing leachate from landfills, leaving utilities without clear guidance on whether landfill disposal is a safer alternative.

Rashi points out that 75 percent of biosolids management options identified in the DRA could pose risks under certain conditions, while the risks associated with landfilling remain uncertain. Given this lack of clarity, utilities may face restrictions before federal regulations are finalized, either from state-level policies or from farmers who may refuse biosolids due to perceived risks.

Biosolid Management: Moving Forward with Collaboration

As regulations continue to evolve, communication among utilities, regulators, and agricultural stakeholders will be essential. Rashi underscores the importance of recognizing that utilities and farmers are not the source of PFAS contamination but rather recipients of these persistent chemicals. While industrial discharges have contributed to PFAS pollution, municipal biosolids remain a valuable resource for soil enrichment and sustainable agriculture. Risk minimization strategies, such as applying biosolids to non-grazing fields and avoiding areas prone to surface runoff, can help maintain these benefits while addressing environmental concerns.

Navigating the complexities of biosolids management in the context of emerging PFAS regulations will require collaboration, adaptability, and ongoing dialogue. Read Rashi’s full analysis in Smart Water Magazine for a deeper dive into the challenges and opportunities facing utilities.