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Abstract Per- and polyfluoroalkyl substances (PFASs) are utilized in specific firefighting foams. The objectives of this study were i) to map PFAS distribution in the soil and groundwater of a firefighter training site active for more than 3 decades, ii) to locate the main points of entry of PFASs into the aquifer and iii) to identify which PFASs seeped most deeply into the soil. A total of 44 soil cores and 17 groundwater samples were collected. Perfluorooctane sulfonate (PFOS), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and 6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) were the most predominant PFASs in surface soil. The highest total PFAS concentrations (up to 357 μg/g) were measured in two areas. Both areas were considered as potential points of entry of PFASs into the aquifer since PFASs were detected in soil 15 m below the surface, despite the presence of clay layers. The highest total PFAS concentrations were recorded in the monitoring wells located in the perimeter of the firefighter training site and in the spring located downgradient in the direction of groundwater flow. They ranged from 300 to 8300 ng/L. The fluorotelomer 6:2 FTAB was quantified in 6 monitoring wells, suggesting that this FT can reach a water table 20 m below the ground's surface. Graphical abstract Image 1 Highlights • PFAS measurement in groundwater and soil cores impacted by firefighter training. • Deep seepage (−15 m) of many PFASs, including fluorotelomers, through soil. • Many monitoring wells and one drinking water resource were contaminated. • Many classes of key fluorinated ingredients of foams were detected. • Some fluorotelomers reached the groundwater despite overlying clay. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the viability of electrochemical oxidation to degrade and mineralize poly- and perfluoroalkyl substances (PFASs) in wastewaters from an industrial facility dedicated to the production of side-chain-fluorinated polymers and fluorotelomer-based products for fire-fighting foams. 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB, 1111 μg/L), 6:2 fluorotelomer sulfonic acid (6:2 FTSA, 242.5 μg/L) and 6:2 fluorotelomer sulfonamide propyl N,N dimethylamine (M4, 34.4 μg/L) were the most abundant PFASs in the industrial wastewater, that also contained perfluorocarboxylic acids (ΣPFCAs, 12.2 μg/L), high TOC and chloride as main anion. 2 L samples were treated in bench scale experiments performed at a current density of 50 mA/cm 2 , in a commercial cell equipped with a boron doped diamond (BDD) anode (70 cm 2 ). 97.1% of the initial PFASs content was removed after 8 h of electrochemical treatment. Furthermore, the TOC removal (82.5%) and the fluoride release confirmed the PFASs mineralization. Based on the evolution of the different PFASs, electrochemical degradation pathways were proposed. Fluorotelomers sulfonamides 6:2 FTAB and M4 would be degraded into 6:2 FTSA, which conversely would give rise to PFHpA and preferentially PFHxA. The latter PFCAs were transformed into shorter-chain PFCAs, and eventually into CO 2 and fluoride. The reported results support the technical viability of BDD electrooxidation for the treatment of PFASs in industrial wastewater. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are emerging contaminants that have been detected in the environment, biota and humans. Drinking water is a route of exposure for populations using water contaminated by PFAS discharges. This research entailed measuring concentrations, mass flows and investigating the fate of dozens PFASs in a river receiving effluents from a fluorochemical manufacturing facility. To measure the total concentration of perfluoroalkyl carboxylic acid (PFCA) precursors, an oxidative conversion method was used. Several dozen samples were collected in the river (water and sediment), in drinking water resources and at different treatment steps on four sampling dates. One PFCA and three fluorotelomers (FTs) were detected up to 62 km downstream from the manufacturing facility. 6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) was the predominant PFAS with a mass flow of 3830 g/day 5.2 km downstream from the facility. At all sampling points, PFAS concentrations in sediment were quite low (< 6 ng/g dw). Five of the 11 investigated wells showed detectable concentrations of PFASs. Interestingly, their profile patterns were different from those observed in the river, suggesting a transformation of PFCA precursors in the sediments of alluvial groundwater. Conventional drinking water treatments (aeration, sand or granular activated carbon filtration, ozonation or chlorination) did not efficiently remove PFASs. Furthermore, an increase in concentration of certain PFASs was observed after ozonation, suggesting that some FTs such as 6:2 FTAB can break down. Only nanofiltration was able to remove all the analyzed PFASs. In the treated water, total PFAS concentrations never exceeded 60 ng/L. The oxidative conversion method revealed the presence of unidentified PFCA precursors in the river. Therefore, 18 to 77% of the total PFCA content after oxidation consisted of unidentified chemical species. In the treated water, these percentages ranged from 0 to 29%, relatively and reassuringly low values. [ABSTRACT FROM AUTHOR]

Here, we developed and validated a headspace-solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS) method for the determination of 14 volatile perfluorinated alkylated substances (PFASs) in water and sediment samples according to SANTE 11945/2015 guidelines. Three fluorotelomer alcohols (FTOHs), two perfluoroalkyl iodides (PFIs), three fluorotelomer iodides (FTIs), four fluorotelomer acrylates and methacrylates (FTACs and FTMACs) and two perfluoroalkyl sulfonamides (FASAs) were analysed simultaneously to assess the occurrence of these compounds from their emission sources to the outlets in water treatment plants. Several SPME parameters were optimised for both water and sediment to maximise responses and keep analysis time to a minimum. In tap water, the limits of quantification (LOQs) were found to be between 20 ng/L and 100 ng/L depending on the analyte, with mean recoveries ranging from 76 to 126%. For sediments, LOQs ranged from 1 to 3 ng/g dry weight depending on the target compound, with mean recoveries ranging from 74 to 125%. SPME considerably reduced sample preparation time and its use provided a sensitive, fast and simple technique. We then used this HS-SPME-GC/MS method to investigate the presence of volatile PFASs in the vicinity of an industrial facility. Only 8:2 FTOH and 10:2 FTOH were detected in a few water and sediment samples at sub-ppb concentration levels. Moreover, several non-target fluorotelomers (12:2 FTOH, 14:2 FTOH and 10:2 FTI) were identified in raw effluent samples. These long-chain fluorotelomers have high bioaccumulative potential in the aquatic environment compared with short-chain fluorotelomers such as 6:2 FTOH and 6:2 FTI. [ABSTRACT FROM AUTHOR]