[Occurrence, Characterization, and Risk Assessment of PFASs in Soil Surrounding Fire-fighting Sites]

This study investigated the occurrence characteristics and environmental risks of per- and polyfluoroalkyl substances （PFASs） in 10 surface soil samples collected from the area surrounding the fire-fighting sites using the UPLC/MS-MS method. A total of 32 out of 34 PFASs were detected in the soils, with concentrations ranging from 9.87 to 1 086.95 ng·g^-1, with an average of 244.88 ng·g^-1. Perfluorocarboxylic acids （PFCAs） were dominated by shorter carbon chains, while other PFASs showed a prevalence of longer carbon chains. Perfluoropropionic acid （PFPrA） and perfluorooctane sulfonic acid （PFOS） were the primary PFCAs and perfluorosulfonates （PFSAs） in most of the samples, respectively. Among PFASs alternatives and precursors, 8∶2 fluorotelomer sulfonate （8∶2 FTSA） was the predominant pollutant, followed by 6∶2 fluorotelomer sulfonate （6∶2 FTSA）. PFASs concentrations in soils at all sampling points were likely influenced by the fire-fighting sites, which varied in different functional areas, following the order of industrial areas > residential areas > agricultural areas. Principal component and correlation analysis results indicated that the use of aqueous film-forming foams （AFFF） was one of the primary sources of PFASs in the soils surrounding the fire-fighting sites. Risk assessment indicated that the ecological and health risks of perfluorooctanoic acid （PFOA） and PFOS at all sampling points were relatively low.