Per-and Polyfluoroalkyl Substances (PFAS) Distribution in Landfill Gas Collection Systems: Leachate and Gas Condensate Partitioning

By Thomas J. Smallwood, Nicole M. Robey, Yalan Liu, John A. Bowden, Thabet M. Tolaymat, Helena M. Solo-Gabriele, and Timothy G. Townsend
J. Haz. Mat.
January 31, 2023
DOI: 10.1016/j.jhazmat.2023.130926

While per- and polyfluoroalkyl substances (PFAS) have been reported extensively in municipal solid waste (MSW) landfill leachate, PFAS have not been quantified in landfill gas or in discrete landfill liquids such as gas condensate (LGC), and the potential for PFAS to partition to the condensate has not been reported. LGC and leachate collected from within gas wells (GWP) from three MSW landfills underwent physical-chemical characterization and PFAS analysis to improve understanding of the conditions under which these liquids form and to illuminate PFAS behavior within landfills. LGC was observed to be clear liquid containing ammonia and alkalinity while GWP strongly resembled leachate – dark in color, high in chloride and ammonia. Notably, arsenic and antimony were found in concentrations exceeding regulatory thresholds by over two orders of magnitude in many LGC samples. LGC contained a lower average concentration of ΣPFAS (19,000 ng L^-1) compared to GWP (56,000 ng L^-1); however, LGC contained more diversity of PFAS, with 53 quantified compared to 44 in GWP. LGC contained proportionally more precursor PFAS than GWP, including more semi-volatile PFAS which are rarely measured in water matrices, such as fluorotelomer alcohols and perfluoroalkane sulfonamido ethanols. This study provides the first detailed comparison of these matrices to inform timely leachate management decisions.

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