Virginie Boiteux

Mass flows and fate of per- and polyfluoroalkyl substances (PFASs) in the wastewater treatment plant of a fluorochemical manufacturing facility

Although industrial sites producing perfluoroalkyl and polyfluoroalkyl substances (PFASs) may introduce these chemicals into the aquatic environment, they are rarely investigated. This study entailed measuring concentrations, mass flows and the fate of 51 PFASs in an industrial wastewater treatment plant receiving raw effluents from a fluorochemical manufacturing facility. Grab and 24-h composite samples were collected at various stages of wastewater treatment over four sampling campaigns. One perfluoroalkyl carboxylic acid (PFCA) and nine fluorotelomers (FTs) were systematically detected in the facilitys raw effluent. The overall PFCA mass flow ranged from 0.6 to 8.6g/day and was negligible compared to the overall mass flow of FTs (from 647 to 2,892g/day). PFCA mass flows increased drastically after secondary treatment (degradation of precursors) and decreased notably after the floatation tank (adsorption onto floatation sludge), but remained at relatively high levels in the final effluent (from 21 to 247g/day). Similar patterns in mass flow were observed for the FTs, with mass loadings discharged into the river ranging from 1,623 to 6,963g/day. Despite analyzing dozens of PFASs, adsorbable organic fluorine determination and oxidative conversion of PFCA precursors showed that a significant part of PFASs remained unidentified. Nevertheless, two overwhelmingly predominant PFASs-6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) and 6:2 Fluorotelomer sulfonamide propyl N,N dimethylamine (M4)-were detected and quantified for the first time in water samples, accounting for >75% of the total PFAS mass flow in the final effluent. This study also provided evidence of soil contamination by the aerosol produced over the aeration basin and inadvertent spillage of pieces of sludge cake.

Analysis of 29 per- and polyfluorinated compounds in water, sediment, soil and sludge by liquid chromatography–tandem mass spectrometry

ABSTRACT Several analytical methods were optimised for the analysis of 29 per- and polyfluoroalkyl substances (PFASs), including perfluorocarboxylic acids, perfluoroalkyl sulphonic acids and fluorotelomers (FTs), such as sulphonate, saturated carboxylic acid, unsaturated carboxylic acid, sulphonamide and sulphonamide betaine (FTAB), in environmental samples in order to assess pollution by PFASs around heavily contaminated sites. Non-filtered water samples were extracted, purified and pre-concentrated by a solid-phase extraction (SPE) procedure. Solid samples (sediments, soils and sludges) were extracted through solvent extraction under acidic conditions and thereafter purified and pre-concentrated using the same SPE procedure as for the water samples. An ultra-high performance liquid chromatography coupled to tandem mass spectrometry in negative electrospray ionisation mode was employed to separate and detect targeted compounds. Twelve labelled internal standards were used to provide an adequate correction compensating for matrix effects. The limits of quantification (LOQs) were between 4 and 10 ng/L in water depending on the analytes. For solid samples, the LOQs were 2 ng/g dry weight (dw) in sediments and soils, and 20 ng/g dw in sludges for all analytes. A surrogate parameter method based on the carboxylation of perfluoroalkyl acid precursors under basic pH conditions was furthermore implemented to estimate the occurrence of non-targeted PFAS compounds. In order to evaluate the reliability of these analytical methods, environmental samples collected around a training area in France, where aqueous fire-fighting foam is used, were analysed. Of all the compounds detected in these environmental samples, 6:2 FTAB was found in the highest concentrations.

Simultaneous determination of perfluoroalkyl iodides, perfluoroalkane sulfonamides, fluorotelomer alcohols, fluorotelomer iodides and fluorotelomer acrylates and methacrylates in water and sediments using solid-phase microextraction-gas chromatography/mass spectrometry

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 20ng/L and 100ng/L depending on the analyte, with mean recoveries ranging from 76 to 126%. For sediments, LOQs ranged from 1 to 3ng/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.

Concentrations and patterns of perfluoroalkyl and polyfluoroalkyl substances in a river and three drinking water treatment plants near and far from a major production source

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 62km downstream from the manufacturing facility. 6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) was the predominant PFAS with a mass flow of 3830g/day 5.2km downstream from the facility. At all sampling points, PFAS concentrations in sediment were quite low (<6ng/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 60ng/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.

Deep seepage of per- and polyfluoroalkyl substances through the soil of a firefighter training site and subsequent groundwater contamination

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 grounds surface.

Tissue Uptake, Distribution, and Elimination of Perfluoroalkyl Substances in Juvenile Perch through Perfluorooctane Sulfonamidoethanol Based Phosphate Diester Dietary Exposure

Perfluorooctane sulfonamidoethanol based phosphate diester (SAmPAP) is a potential perfluorooctanesulfonate (PFOS) precursor. To examine whether SAmPAP exposure would result in fish contamination by perfluoroalkyl and polyfluoroalkyl substances (PFASs), juvenile Eurasian perch were dietarily exposed to this compound (dosed group) or exposed to the same tank water but fed control feed (control group). SAmPAP and metabolites were monitored in the muscle, liver, and serum during the 45-day exposure phase and 35-day depuration phase. SAmPAP was only detected in the dosed group and the absorption efficiency (0.04-2.25%) was very low, possibly related to its low bioavailability in the gastrointestinal tract, steric constraints in crossing biological membranes, and clearing by enterohepatic circulation. Although SAmPAP was biotransformed and eliminated at a slow rate (t1/2 > 18 days), its biomagnification factor was low. The observed metabolites in fish were N-ethyl perfluorooctane sulfonamidoacetic acid, perfluorooctane sulfonamidoacetic acid, perfluorooctane sulfonamide, and PFOS. Considering that SAmPAP was the only source of PFASs in the tanks, the occurrence of metabolites indicates that SAmPAP could be biotransformed in fish and contribute to PFOS bioaccumulation. However, levels of metabolites were not significantly different in the dosed and control groups, indicating that metabolite excretion followed by re-exposure to these metabolites from water was the main uptake route.