Sources and Seasonal Variations of Per- and Polyfluoroalkyl Substances (PFAS) in Surface Snow in the Arctic

• DOI: 10.1021/acs.est.4c08854
• Publication Date: 2024-11-26T13:01:18Z
• Authors: William F. Hartz; Maria K. Björnsdo...; Leo W. Y. Yeung; Jack D. Humby; Sabine Eckhardt; Nikolaos Evangeliou; Ingrid Ericson Jo...; Anna Kärrman; Roland Kallenborn
• Keywords: Hydroxyl radicals; GenX; atmospheric deposition; trifluoroacetic acid; Precursors; Trifluoroacetic acid; Atmospheric deposition; hydroxylradicals; Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss; solar flux; Svalbard; precursors; Ensure healthy lives and promote well-being for all at all ages; Responsible Consumption and Production; Solar flux

[Image: see text] Per- and polyfluoroalkyl substances (PFAS) are persistent anthropogenic contaminants, some of which are toxic and bioaccumulative. Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) can form during the atmospheric degradation of precursors such as fluorotelomer alcohols (FTOHs), N-alkylated perfluoroalkane sulfonamides (FASAs), and hydrofluorocarbons (HFCs). Since PFCAs and PFSAs will readily undergo wet deposition, snow and ice cores are useful for studying PFAS in the Arctic atmosphere. In this study, 36 PFAS were detected in surface snow around the Arctic island of Spitsbergen during January–August 2019 (i.e., 24 h darkness to 24 h daylight), indicating widespread and chemically diverse contamination, including at remote high elevation sites. Local sources meant some PFAS had concentrations in snow up to 54 times higher in Longyearbyen, compared to remote locations. At a remote high elevation ice cap, where PFAS input was from long-range atmospheric processes, the median deposition fluxes of C(2)–C(11) PFCAs, PFOS and HFPO–DA (GenX) were 7.6–71 times higher during 24 h daylight. These PFAS all positively correlated with solar flux. Together this suggests seasonal light is important to enable photochemistry for their atmospheric formation and subsequent deposition in the Arctic. This study provides the first evidence for the possible atmospheric formation of PFOS and GenX from precursors.