Although there has been a lot of attention focused on the presence of per- and polyfluoroalkyl substances (PFAS) in landfill leachate, landfills are also likely emitting PFAS to ambient air. This talk will focus on what is known about PFAS emissions to air, focusing on recent research that will be shedding light on PFAS emissions. About 10 years ago, research studies identified landfills as a possible source of emissions of PFAS (e.g., Ahrens et al., 2011). Samples collected in ambient air near landfills were found to have higher levels of fluorotelomer alcohols (FTOHs), which are a category of PFAS that have replaced compounds such as PFOA and PFOS in commerce. Unlike PFOA and PFOS, FTOHs are highly volatile, and are likely present in landfill gas. Hence, fugitive emissions of FTOHs in uncollected landfill gas may be a relevant emission source, as well as any FTOHs in collected landfill gas that are not destroyed by combustion. Studies of PFAS emissions from landfills are being conducted, and information will soon be available. A nationwide study on PFAS in landfill gases (LFG) is underway at NC State University (NC State), and preliminary LFG analyses has identified and confirmed the presence of FTOHs in landfill gas (de la Cruz, 2021) consistent with published PFAS measurements in ambient air near landfills. The NC State study will not examine destruction/transformation of PFAS in flares and energy recovery devices that combust LFG. However, we are collaborating with the University of Vermont on a study funded by the Environmental Research and Education Fund to measure PFAS destruction in landfill gas-to-energy engines and landfill gas flares. Data and information available from these studies will be presented, as well as interpretation as to its importance. Emissions estimates will be used in conjunction with other inputs to the U.S. EPA’s AERMOD system to estimate PFAS concentrations in ambient air due to representative facility emissions. Incremental impacts will be compared to reported background concentrations of PFAS in ambient air, and potential incremental exposure to PFAS will be compared to estimates of background exposure to PFAS in order to gauge the importance of PFAS emissions from combustion devices and fugitive emissions.
References
Ahrens et al. (2011). Wastewater Treatment Plant and Landfills as Sources of Polyfluoroalkyl Compounds to the Atmosphere. Environ Sci Technol 45:8098-8105. de la Cruz (2021). Personal communication with Dr. Tino de la Cruz, NC State University.
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