CCR Seminar: Residual Challenges, Occurrence and Transport of PFAS in Land Applied Biosolids

Abstract:

Per and polyfluoroalkyl substances (PFAS) do not degrade in conventional wastewater treatment processes and are found in wastewater effluent and biosolids. In 2022, 6.5 million tons of biosolids were generated in the US, and 23% were land applied in agricultural settings. Due to the ubiquity of PFAS in biosolids, there is increasing regulatory focus on the practice of land application, despite other benefits such as nutrient management. Here we established PFAS mass balances in 50 biosolids collected across the US using targeted analysis, nontargeted analysis, and the total oxidizable precursor (TOP) assay. Two biosolids were amended into unimpacted, agricultural soils for use in column transport experiments. Occurrence data showed occurrence of PFAS in 100% of biosolids analyzed with so-called "unknown" precursors comprising up to 90% of the total PFAS mass. When compared to provisional biosolids regulations adopted by many US states for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS),…