Nationwide Estimate of Volatile Per- and Polyfluoroalkyl Substance (PFAS) Emissions from U.S. Landfills via Landfill Gas

Estimates of annual per- and polyfluoroalkyl substances (PFAS) emissions from landfill gas (LFG) using data from a nationwide sampling campaign have not been reported. The objective of this study was to characterize volatile PFAS in LFG and to estimate the annual mass of volatile PFAS released from US landfills. LFG samples were collected from 30 landfills in 17 states represented by different annual precipitation regions. PFAS concentrations varied by orders of magnitude, with a median concentration of 19,000 ng/m 3. Fluorotelomer alcohols, 6:2 and 8:2 FTOH, are the dominant PFAS in LFG, accounting for more than 95% of the total PFAS concentration. Minor components such as fluorotelomer olefins (FTOs) are also present, with concentrations ranging from 0–28,000 ng/m 3 and a median of 316 ng/m 3. The variability in PFAS concentrations was influenced by precipitation, as well as temporal and site-specific factors. By coupling the median concentration of PFAS with an estimate of US LFG emissions, it is estimated that 836 kg/yr of volatile PFAS are emitted from US landfills in uncollected gas with a 95% confidence interval (2.5% to 97.5% of the distribution) of 15–5,590 kg/yr. This estimate is comparable to ∼600 kg of PFAS released annually into landfill leachate.