Analysis of perfluoroalkyl acids (PFAAs) in contaminated soils from Bennington, VT

Perfluoroalkyl acids (PFAAs) are compounds used and produced by industrial companies for their unique characteristics like hydrophobicity, hydrophilicity, chemical stability, thermal stability, and non-flammability.  Most commonly, PFAAs are used in the manufacture of everyday household products like paper plates, pizza boxes, non-stick pans, and microwaveable popcorn bags. They are also found in substantial industrial uses like fire-fighting foam, semiconductors, and hydraulic fluids. In 1968, PFAAs were detected in human blood serum, which later caused the EPA to pressure industrial Teflon companies to phase out the C8 chemistry voluntarily. These chemicals were deemed Contaminants of Emerging Concern (CECs) because of their persistence, bioaccumulation, and toxicity. Although industrial companies have agreed to phase out perfluorooctanoic acid (PFOA) use, the replacement compounds may present the same issues. Although there is an EPA health advisory level of no more than 70 parts per trillion for the combined concentrations of PFOA and perfluorooctane sulfonate (PFOS) in drinking water, there is a lack of regulation. Though PFAAs have been extensively studied in water, at the moment, there is no EPA-certified method for the analysis of PFAAs in soils. In this work, an efficient soil extraction method is presented and applied to contaminated soils from Bennington, Vermont, where PFOA concentrations in soil have been found to be in the parts per billion (ng/g) range. In this study, PFOA concentrations in soils were found to range from 0.79 - 142 ng/g wet weight, within the Vermont Department of Health soil screening level of 300 parts per billion, and consistent with what the Vermont Agency of Natural Resources in the Department of Environmental Conservation reported in 2016.