A province-wide mapping of per- and polyfluoroalkyl substances (PFAS) in surface waters of the St. Lawrence River watershed, Québec, Canada

作者：Termeh Teymoorian, Gabriel Munoz, Sung Vo Duy, Marc-Antoine Vaudreuil, Min Liu, Jinxia Liu, Sébastien Sauvé · 发表于：The Science of The Total Environment · 年份：2025 · DOI：10.1016/j.scitotenv.2025.180429 · 被引用次数：6 · 研究领域：Per- and polyfluoroalkyl substances research、Toxic Organic Pollutants Impact、Atmospheric chemistry and aerosols

This study investigates the spatial distribution of per - and polyfluoroalkyl substances (PFAS) in surface waters of the St. Lawrence watershed, Québec, Canada. Water samples (232 sites, overall n = 447) were collected along a ~ 700-km longitudinal gradient of the St. Lawrence as well as in tributary rivers, streams, creeks, and lakes with different anthropogenic pressures. St. Lawrence samples had a mean and median Σ 77 PFAS both at ~12 ng/L (the maximum at 26 ng/L) and PFAS composition profiles dominated by perfluorooctane sulfonate (PFOS: 19 % of the summed PFAS), perfluorobutanoic acid (PFBA: 16 %), and perfluorooctanoic acid (PFOA: 14 %). Samples were also characterized by frequent detections of perfluorobutane sulfonamide and perfluoroethylcyclohexane sulfonate. PFAS concentrations slightly decreased from west to east along the St. Lawrence River and cross-sections revealed higher levels in the Great Lakes/Central water mass than in the Ottawa River/Northern water mass. Tributary rivers displayed a much wider span of PFAS levels and were influenced by local point sources, with common PFAS signatures revealed by a Kohonen mapping (artificial neural networks). Top hotspots (Σ 77 PFAS = ~100–3600 ng/L) included watersheds downstream three airports, where positive ion mode fluorotelomer betaines 6:2 FTAB and 5:1:2 FTB also occurred at the highest levels (max = 156 and 570 ng/L, respectively). A mass balance analysis indicated, however, that tributaries contributed marginall...