Biosolids as a PFAS Source
Biosolids — treated municipal wastewater solids applied as fertilizer on agricultural land — are a significant pathway for PFAS introduction into farmland soils. Wastewater treatment plants receive PFAS from multiple household and industrial sources in their service areas. While treatment processes remove some dissolved PFAS, the compounds concentrate in the solid sludge fraction. Land application of PFAS-containing biosolids has contaminated agricultural soils and shallow groundwater at farms across the country, with documented impacts on livestock, produce, and water supplies.
Maine’s Biosolids Crisis
Maine emerged as a focus of the biosolids contamination issue after widespread application of PFAS-contaminated biosolids between the 1980s and early 2000s. Farmers, whose land was promoted as suitable for biosolids application, later found their soil, groundwater, milk, and livestock contaminated with PFAS. Some Maine farms were subsequently taken out of production, with significant economic consequences for farm families. Maine now has comprehensive biosolids PFAS regulations and is pursuing litigation against biosolids brokers and municipalities.
Regulatory Response
The EPA has begun developing PFAS limits for biosolids under the Clean Water Act, following years of regulatory inaction on this pathway. Several states — including Maine, Michigan, and Connecticut — have established interim limits or outright bans on land application of biosolids with detected PFAS. The challenge is that essentially all biosolids contain measurable PFAS, making zero-tolerance standards impractical without alternative disposal pathways.
Food Safety Implications
FDA testing of produce and dairy products from farms with documented biosolids PFAS contamination has found elevated PFAS in some food products. The combination of contaminated irrigation water and PFAS-containing biosolids creates multiple soil and water contact pathways for crop PFAS uptake. Consumers near farms with known biosolids histories and households relying on well water near biosolid application areas face compounded PFAS exposure risk from both food and water pathways.