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Subsurface Per- and Polyfluoroalkyl Substances (PFAS) Distribution at Two Contaminated Sites
Citation:
Schumacher, B., J. Zimmerman, K. Bronstein, R. Warrier, C. Lutes, E. Escobar, AND A. Williams. Subsurface Per- and Polyfluoroalkyl Substances (PFAS) Distribution at Two Contaminated Sites. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-23/294, 2023.
Impact/Purpose:
Certain per- and polyfluoroalkyl substances (PFAS) have sufficient vapor pressures to be designated as vapor-forming chemicals and; thus, be a concern for vapor intrusion into the indoor air of residences and buildings overlying a contaminated soil or groundwater source. Sampling and analytical methods for several PFAS were demonstrated. Multiple PFAS species were found in the groundwater, soil, soil gas, and subslab soil gas. With the presence of PFAS in soil, soil gas (including subslab soil gas), and groundwater, the potential for a vapor intrusion pathway has been recognized; however, the final confirmatory analysis of indoor air to complete the exposure pathway is lacking. The vapor intrusion of volatile PFAS may pose health risks to building occupants and should, therefore, warrant consideration during vapor intrusion assessments at facilities where high concentrations are present in shallow soils and groundwater.
Description:
At least four polyfluorinated organic substances (i.e., 4:2-, 6:2-, 8:2- and 10:2- fluorotelomer alcohols; FTOHs) have sufficient vapor pressure (VP) to be designated as vapor-forming chemicals. Based on current guidance, vapor-forming chemicals warrant investigation for vapor intrusion when they occur as subsurface contaminants at sites subject to a federal statute for land cleanup (e.g., CERCLA, RCRA corrective action). This investigation represents the U.S. Environmental Protection Agency’s initial research into whether the VI exposure pathway is pertinent to per- and polyfluoroalkyl substances (PFAS) chemicals with a focus on FTOHs, which are common chemical intermediaries and byproducts in some PFAS manufacturing operations. Several PFAS were found/detected in multiple subsurface matrices underlying a building in which PFAS are manufactured.