Source Apportionment of Per- and Polyfluoroalkyl Substances in Landfill Leachate, Including Total Oxidizable Precursor Assay

Event Type: Webinar (Zoom Access)

Speaker: Staci Capozzi, Indiana University in Bloomington

Abstract:

Per- and polyfluoroalkyl substances (PFAS) are difficult to characterize in the environment with existing analytical approaches along with complex sources, fate, and transport. We evaluated PFAS in leachate combining pre- and post-total oxidizable precursor (TOP) assay samples from 17 landfills across Washington State using positive matrix factorization (PMF). Total PFAS concentrations (Σ30PFAS) ranged from 61-173,000 ng/L and 580-36,000 ng/L in pre-TOP and post-TOP leachate samples, respectively. PMF modeling produced five-factors. Factor 1 was dominated by 5:3FTCA where Σ30PFAS was 61% and 1.5% in pre-TOP and post-TOP samples, respectively. Factor 2 contained primarily 5:3FTCA and PFBS (20% of Σ30PFAS in pre-TOP and 26% post-TOP). Factor 3 is thought to represent a stage of oxidation and consisted primarily of shorter-chain congeners with PFHxS (8% of Σ30PFAS in pre-TOP and 19% post-TOP). Factor 4 was dominated by PFOS and has minor contributions to Σ30PFAS. Factor 5, highly loaded with PFCAs, represented oxidation of precursors, and explained 10% of PFAS in the pre-TOP samples suggesting the TOP assay approximates the same oxidative process that occurs in landfills. We speculate main sources of PFAS in Washington landfill leachate were primarily carpet, textiles, and food packaging based on the dominance of 5:3FTCA.