The U.S. EPA’s recent draft risk assessment (DRA) for PFOA and PFOS in biosolids has ignited discussions on biosolids management and its impact on utilities. While the EPA has previously used risk assessments to shape regulatory guidance, key differences in this DRA’s development have raised concerns. Academic experts and industry organizations will submit feedback, which may lead to modifications before finalization. However, the current draft introduces challenges that require an accurate understanding of the DRA and proactive planning.
The DRA is not a regulation and does not establish enforceable limits. Historically, risk assessments and risk management were considered together before regulations were proposed. The risk management analysis is still pending, indicating that national regulatory limits may not be imminent.
The DRA focuses on exposure risks for hypothetical "farm families"– those almost exclusively consuming meat, eggs, dairy, crops, and water from land where biosolids were applied. It does not reflect risks to the general public which has diverse food sources or the national food supply, as biosolids are applied to less than 1% of available U.S. agricultural land (National Research Council, Biosolids Applied to Land: Advancing Standards and Practices, 2002). EPA modeled exposure pathways and scenarios where biosolids with 1 part per billion PFOA and PFOS were applied to farmland once annually for 40 years. The assessment assumed that a farm family subsisted almost entirely on food and water from the farm for 10 years. Based on these assumptions, the EPA determined that some modeled scenarios exceeded acceptable health risk thresholds for the farm family.
The draft risk assessment indicated that 75 per cent of utilities’ management options represent risks from PFOS or PFOA under some scenarios
As of 2022, 56% of biosolids were land-applied, 3% monofilled, 16% incinerated, 24% landfilled, and 1% managed by other means. The DRA did not quantify risks from incineration but acknowledged likely risks. Landfilling was also excluded from the analysis, despite a generation of PFAS-containing leachate. In summary, the DRA indicated that 75% of utilities’ management options represent risks from PFOS or PFOA under some scenarios and the risk associated with landfilling remains unassessed. So what can utilities do?
Utilities can prepare now by focusing on data collection and risk mitigation. Recommended actions include conducting PFAS sampling in biosolids, updating industrial user inventories for better source control, and working with biosolids management partners to minimize risks from land application. Strategic planning is essential as states and localities may impose restrictions before federal regulations emerge. Some farmers may also refuse biosolids due to perceived risks. Utilities should explore diversified management strategies, including regional partnerships for centralized processing and advanced thermal technologies that show promise for PFAS destruction. However, most of these technologies are unproven at scale long-term and require significant investment, making feasibility assessments and discussions with regulators and stakeholders critical.
Clear communication with stakeholders — including regulators, legislators, and farmers — is crucial. While industrially impacted solids have caused real harm, it is essential to recognize that both farmers and utilities are receivers, not producers, of PFAS. Municipal biosolids remain a valuable resource for soil enrichment, supporting sustainable and cost-effective agriculture. Risk minimization strategies — such as applying biosolids to non-grazing fields and avoiding areas prone to surface water runoff — can help maintain these benefits while reducing PFAS concerns.
Balancing environmental protection with practical implementation is key. Collaboration among all stakeholders will be essential to develop sustainable biosolids management solutions. As the industry adapts to evolving PFAS regulations, maintaining open dialogue and sharing best practices will be crucial for navigating this complex landscape.