Sources Of Polyfluoroalkyl Substances Research Articles

Predicting the risk of GenX contamination in private well water using a machine-learned Bayesian network model

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants that pose significant challenges in mechanistic fate and transport modeling due to their diverse and complex chemical characteristics. Machine learning provides a novel approach for predicting the spatial distribution of PFAS in the environment. We used spatial location information to link PFAS measurements from 1207 private drinking water wells around a fluorochemical manufacturing facility to a mechanistic model of PFAS air deposition and to publicly available data on soil, land use, topography, weather, and proximity to multiple PFAS sources. We used the resulting linked data set to train a Bayesian network model to predict the risk that GenX, a member of the PFAS class, would exceed a state provisional health goal (140 ng/L) in private well water. The model had high accuracy (ROC curve index for five-fold cross-validation of 0.85, 90% CI 0.84–0.87). Among factors significantly associated with GenX risk in private wells, the most important was the historic rate of atmospheric deposition of GenX from the fluorochemical manufacturing facility. The model output was used to generate spatial risk predictions for the study area to aid in risk assessment, environmental investigations, and targeted public health interventions.

Sources, Fate, and Plant Uptake in Agricultural Systems of Per- and Polyfluoroalkyl Substances

Abstract Purpose of Review Per- and polyfluoroalkyl substances (PFAS) are a family of > 4700 recalcitrant compounds, many of which are ubiquitous in the environment. This review aims to (1) identify PFAS sources and fate processes relevant to agricultural systems and (2) expand on plant uptake mechanisms and plant responses to PFAS. Recent Findings The number of PFAS being quantified in studies involving soil, water, and plants is increasing. Transformation of precursors that tend to stay in the rhizosphere can lead to long-term PFAS reservoir to plants. Some PFAS are readily taken up, particularly the shorter-chain PFAS, and can evoke metabolic responses and phytotoxic effects at high concentrations. PFAS translocation from roots to shoots occurs through both active and passive transport mechanisms. Both PFAS uptake and effects vary between and within species. Summary As new PFAS emerge, it will be necessary to continue expanding the list of PFAS quantified in land-applied media and assessing their accumulation potential in plants. While controlled laboratory or greenhouse studies have merit, comprehensive field studies are needed to provide clarity on PFAS fate and their relative risk in agricultural systems. Field studies should include identifying site-specific PFAS sources, quantifying a broader suite of PFAS and identifying potential precursors, evaluating plant uptake of replacement PFAS, reporting of soil properties and climatic conditions, and assessing risk of impacts to source and irrigation waters. This information can be utilized to inform future studies towards evaluating and mitigating risks to our food chain associated with PFAS in agricultural systems.

Identifying and Managing Aqueous Film-Forming Foam-Derived Per- and Polyfluoroalkyl Substances in the Environment.

The use of aqueous film‐forming foam (AFFF) has resulted in the widespread occurrence of per‐ and polyfluoroalkyl substances (PFAS) in groundwater, drinking water, soils, sediments, and receiving waters throughout the United States and other countries. We present the research and development efforts to date by the Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) to measure PFAS in the environment, characterize AFFF‐associated sources of PFAS, understand PFAS fate and behavior in the environment, assess the risk to ecological receptors, develop in situ and ex situ treatment technologies for groundwater, treat soils and investigation‐derived wastes, and examine the ecotoxicity of PFAS‐free fire suppression formulations. Environ Toxicol Chem 2021;40:24–36. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Per- and Polyfluoroalkyl Substances in Ducks and the Relationship with Concentrations in Water, Sediment, and Soil.

The present study examined the occurrence and concentration of per- and polyfluoroalkyl substances (PFAS) measured in game ducks (13 compounds), water, sediment, and soils (33 compounds) in waterways in Victoria, Australia. The study aimed to identify potential ecological and human health risks from measured PFAS concentrations. Four species of duck and samples of water, sediment, and soil were collected from 19 wetlands, which were chosen based on their popularity as hunting locations. The risks posed by 3 PFAS (perfluorooctanoic acid, perfluorohexane sulfonic acid [PFHxS], and perfluorooctane sulfonic acid [PFOS]) to the environment and human health were assessed using available national ecological and human health guidelines. A diverse range of short- and long-chain carboxylic and sulfonic acids were found in the environment and in ducks. Concentrations were generally low and varied between wetlands, duck species, tissue analyzed (breast or liver), and environmental compartment (water, sediment, soil). Higher PFOS concentrations in water and sediments were observed at wetlands near sources of contamination (i.e., a defense base or urban environment). Elevated PFOS and PFOS + PFHxS concentrations in ducks were observed near local point sources but also at wetlands with no known point sources of contamination. There were clear differences in PFAS concentrations detected in duck tissues versus the environment, highlighting complexities of bioaccumulation, movement of animals, and spatiotemporal variation and raising questions about the relevance of using abiotic criteria to assess risk to biota. Human health risk assessment showed that only ducks inhabiting wetlands near local sources of PFAS were likely to pose a risk to consumers. Further studies are required to improve our knowledge of PFAS toxicokinetics and chronic impacts in biota to guide management decisions. Environ Toxicol Chem 2021;40:846-858. © 2020 SETAC.

Bioaccumulation of Per- and polyfluoroalkyl substances (PFASs) in a tropical estuarine food web

The biomagnification of per- and polyfluoroalkyl substances (PFASs) was investigated in a tropical mangrove food web from an estuary in Bahia, Brazil. Samples of 44 organisms (21 taxa), along with biofilm, leaves, sediment and suspended particulate matter were analyzed. Sum (∑) PFAS concentrations in biota samples were dominated by perfluorooctane sulfonate (PFOS, 93% detection frequency in tissues; 0.05 to 1.97 ng g−1 ww whole-body (wb)), followed by perfluorotridecanoate (PFTrDA, 57%; 0.01 to 0.28 ng g−1 ww wb). PFOS precursors such as perfluorooctane sulfonamide (FOSA, 54%; 0.01 to 0.32 ng g−1 ww wb) and N-ethyl perfluorooctane sulfonamide (EtFOSA; 30%; 0.01 to 0.21 ng g−1 ww wb) were also detected. PFAS accumulation profiles revealed different routes of exposure among bivalve, crustacean and fish groups. Statistics for left-censored data were used in order to minimize bias on trophic magnification factors (TMFs) calculations. TMFs >1 were observed for PFOS (linear + branched isomers), EtFOSA (linear + branched isomers), and perfluorononanoate (PFNA), and in all cases, dissimilar accumulation patterns were observed among different trophic positions. The apparent biodilution of some long-chain PFCAs through the food chain (TMF < 1) may be due to exposure from multiple PFAS sources. This is the first study investigating bioaccumulation of PFASs in a tropical food web and provides new insight on the behavior of this ubiquitous class of contaminants.

Legacy and emerging semi-volatile organic compounds in sentinel fish from an arctic formerly used defense site in Alaska

The Arctic is subject to long-range atmospheric deposition of globally-distilled semi-volatile organic compounds (SVOCs) that bioaccumulate and biomagnify in lipid-rich food webs. In addition, locally contaminated sites may also contribute SVOCs to the arctic environment. Specifically, Alaska has hundreds of formerly used defense (FUD) sites, many of which are co-located with Alaska Native villages in remote parts of the state. The purpose of this study was to investigate the extent of SVOC contamination on Alaska’s St. Lawrence Island through the analysis of sentinel fish, the ninespine stickleback (Pungitius pungitius), collected from Troutman Lake located within the watershed of an FUD site and adjacent to the Yupik community of Gambell. We measured the concentrations of legacy and emerging SVOCs in 303 fish samples (81 composites), including polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organophosphate esters (OPEs) and their diester metabolites, and per- and poly-fluoroalkyl substances (PFAS). PBDEs and PCBs were the most abundant SVOC groups found in stickleback with ΣPBDE and ΣPCB median concentrations of 25.8 and 10.9 ng/g ww, respectively, followed by PFAS (median ΣPFAS 7.22 ng/g ww). ΣOPE and ΣOPE metabolite concentrations were lower with median concentrations of 4.97 and 1.18 ng/g ww, respectively. Chemical patterns and distributions based on correlations and comparison with SVOC concentrations in stickleback from other parts of the island suggest strong local sources of PCBs, PBDEs, and PFAS on St. Lawrence Island.

Per‐ and polyfluoroalkyl substances in commercially available biosolid‐based products: The effect of treatment processes

Per- and polyfluoroalkyl substances (PFAS) have been used in a variety of consumer and industrial products and are known to accumulate in sewage sludge due to sorption and their recalcitrant nature. Treatment processes ensure safe and high-quality biosolids by reducing the potential for adverse environmental impacts such as pathogen levels; however, they have yet to be evaluated for their impact on the fate of PFAS. The objective of this study was to compare PFAS concentrations in four commercially available biosolid-based products that received different types of treatments: heat treatment, composting, blending, and thermal hydrolysis. Seventeen perfluoroalkyl acids (PFAAs) were quantified using liquid chromatography with tandem quadrupole time-of-flight mass spectrometry followed by screening for 30 PFAA precursors. Treatment processes did not reduce PFAA loads except for blending, which served only to dilute concentrations. Several PFAA precursors were identified with 6:2 and 8:2 fluorotelomer phosphate diesters in all samples pre- and post-treatment. PRACTITIONER POINTS: Heat treatment and composting increased perfluoroalkyl acid (PFAA) concentrations. Only dilution from blending with non-PFAS material decreased PFAA concentrations. Thermal hydrolysis process had no apparent effect on PFAA concentrations. PFAS sources are a greater driver of PFAS loads in biosolid-based products than treatment processes.

A framework and simple decision support tool for groundwater contamination assessment in an urban redevelopment precinct

Overcoming barriers to large-scale urban redevelopment on brownfield land is an essential step in the global drive toward achieving the UN’s sustainable development goals. Arguably the most significant barrier is site contamination. Decision support tools (DSTs) are potentially effective ways to assess contaminated sites and evaluate different remediation/management strategies as appropriate to local conditions. Whilst there has been extensive development of DSTs for single contaminated sites, only a limited number are available for assessing contamination at the ‘precinct’ (district) scale. This paper presents a framework and simple DST for the assessment of contaminated groundwater, using Australia’s largest urban redevelopment project, Fishermans Bend in Melbourne, as a case study. The value of the inclusion of precinct-wide data into individual site-scale investigations is demonstrated via the DST. Common contaminant sources identified across Fishermans Bend include fill contaminated with heavy metals, legacy landfill leachate containing heavy metals and per- and poly-fluoroalkyl substances (PFAS), and naturally occurring ammonia and methane in organic-rich sediments. By comparison, point sources of heavy metals and PFAS appear related to industrial sources. By using the DST, environmental practitioners and auditors can more effectively separate background conditions from point sources, characterise the ambient conditions of the aquifer and their relationships to natural and anthropogenic processes, and use contaminant data to inform remedial options assessment. Where these increasingly complex and varied environmental datasets can be collected, stored and managed within one central database, cross- or inter-disciplinary collaborations may drive improvements in solving environmental problems which typically arise during the redevelopment process.

Effectiveness of point-of-use/point-of-entry systems to remove per- and polyfluoroalkyl substances from drinking water.

The contamination of groundwater sources with per- and polyfluoroalkyl substances (PFAS) in the United States is a widespread problem for the drinking water industry. Well water supplies in the municipalities of Fountain, Security, and Widefield, Colorado, contain perfluorooctanoic acid and perfluorooctane sulfonate levels greater than the U.S. Environmental Protection Agency (USEPA) health advisory level of 70 ng/L. The source of PFAS has been associated with aqueous film-forming foam at Peterson Air Force Base. To assist property owners and limit the exposure of PFAS to residential drinking water systems, treatability studies were conducted by the USEPA on the PFAS removal effectiveness of commercially available point-of-use/point-of-entry units using reverse osmosis treatment and granular activated carbon adsorbents. Household water systems were tested with a test water containing the water quality characteristics and six PFAS contaminants found in Widefield aquifer region groundwater samples. This study also documents the installation, startup, and continuous/intermittent operation of the treatment systems.

Distribution, partitioning behavior and positive matrix factorization-based source analysis of legacy and emerging polyfluorinated alkyl substances in the dissolved phase, surface sediment and suspended particulate matter around coastal areas of Bohai Bay, China

The concentrations and spatial occurrences of 17 legacy per- and polyfluoroalkyl substances (PFAS) and 4 emerging PFAS in the coastal water-dissolved phase, surface sediment phase and suspended particulate matter (SPM) in the coastal areas of Bohai Bay were investigated. In addition, the partition behaviors of PFAS in the water-SPM system and water-sediment system and the potential sources of PFAS in the marine environment were revealed. The total concentrations of PFAS (∑PFAS) in the water-dissolved phase, surface sediment and SPM were 20.5–684 ng/L, 2.69–25.0 ng/g dry weight (dw) and 4.39–527 ng/g dw, respectively. The level of PFAS contamination in the coastal areas of Shandong Province was higher than that in other areas. The average partition coefficients (log Kd) of PFAS in the water-SPM system and water-sediment system were 1.56–3.57 and 0.72–2.95, respectively. Long-chain PFAS and PFECHS (perfluoroethylcyclohexane sulfonate) have a higher log Kd than that of short-chain PFAS. PFAS with short carbon chains were mainly detected in the water-dissolved phase, but long-chain PFAS mainly occurred in the surface sediment and SPM phases. Source analysis based on the positive matrix factorization (PMF) model found that erosion inhibitor factories, aqueous film-forming foam factories, metal plating plants, fluoropolymer chemical manufacture and food contact materials were the main sources of PFAS in Bohai Bay. These results improved our understanding of the partitioning behavior and sources of PFAS in aquatic environments.

Association between Per- and Polyfluoroalkyl Substances (PFASs) and Thyroid Hormones in a High- Exposed Swedish Population

Per- and polyfluorinated compounds (PFASs) have endocrine disrupting properties. Alterations in thyroid hormone homeostasis have also been observed in animal experimental studies, and in some cross-sectional studies in the general population, often with ambiguous results, and data for other PFASs than PFOA and PFOS is scarce.In December 2013 high levels of PFASs were detected in one out of two waterworks in Ronneby, a municipality with 28000 inhabitants. This waterworks supplied 1/3 of the households. The source of PFASs was groundwater contamination from firefighting foam. This &amp;#8220;natural experiment&amp;#8221; enables epidemiological investigations over a wide exposure span, dominated by exposure to PFOS and PFHxS.Between 2014-15, 3285 individuals with a wide age span from the municipality and a nearby reference community participated in open blood samplings. We investigated thyroid hormone levels in this combined group, having serum levels for PFOS median 160 (10, 90 percentiles 11, 560) ng/ml, PFHxS 140 (6, 540) and PFOA 9 (2, 29) ng/ml. The associations between PFASs and thyroid hormone were assessed using linear regression in stratified groups of gender and age (2-11, 12-19, 20-49, 50&amp;#43;).It was found that in girls aged 2-11, there were significant positive associations between PFASs and free T3 (fT3). A doubling of PFASs level was associated with 1-2% increase. In other age groups of female, there were no significant associations. In males, no significant associations were found between PFASs and fT3 in any age groups. For fT4, a weak positive association (p&amp;lt;0.1) were observed in females aged 12-19. In boys aged 2-11, there were positive association. Statistically significant associations between PFASs and TSH were not observed in any age groups neither for females or males.In general, females were more sensitive to PFASs with respected to thyroid hormones. Prepubertal girls in this highly exposed group showed a small increase of free T3 with increasing PFAS exposure.

Sulfluramid use in Brazilian agriculture: A source of per- and polyfluoroalkyl substances (PFASs) to the environment

N-Ethyl perfluorooctane sulfonamide (EtFOSA) is a perfluorooctane sulfonate (PFOS) precursor and the active ingredient in sulfluramid, a pesticide which is used extensively in Brazil for management of leaf cutting ants. Here we investigate the occurrence of EtFOSA, PFOS, and other per- and polyfluoroalkyl substances (PFASs) in soil, eucalyptus leaves, water (ground, riverine, and coastal (estuarine/marine)) and coastal sediment from an agricultural region of Bahia State, Brazil. This area contains a larger number of eucalyptus plantations where sulfluramid is suspected to be applied. Soil, leaves, and coastal water (marine/estuarine) contained ∑PFAS concentrations of up to 5400 pg g−1, 979 pg g−1, and 1020 pg L−1, respectively, with PFAS profiles generally dominated by PFOS and perfluorooctane sulfonamide (FOSA). Coastal sediment contained ∑PFAS concentrations of up to 198 pg g−1, with PFOS, FOSA, and perfluorooctanoic acid (PFOA) being the most frequently observed PFASs. These substances are all potential EtFOSA transformation products, pointing to sulfluramid as a possible source. In riverine water, ∑PFAS concentrations of up to 8930 pg L−1 were observed. PFOS and PFOA were detected in all river water samples. Groundwater also exhibited PFAS contamination (5730 pg L−1 ∑PFASs), likely from sulfluramid use. The observation of other PFASs (e.g. perfluorobutanoic acid) in freshwater suggests that other PFAS sources (in addition to sulfluramid) may be important in this region. Overall, these data support the hypothesis that sulfluramid use contributes to the occurrence of PFASs in the Brazilian environment.

Evaluation and Management Strategies for Per- and Polyfluoroalkyl Substances (PFASs) in Drinking Water Aquifers: Perspectives from Impacted U.S. Northeast Communities

Background:Multiple Northeast U.S. communities have discovered per- and polyfluoroalkyl substances (PFASs) in drinking water aquifers in excess of health-based regulatory levels or advisories. Regional stakeholders (consultants, regulators, and others) need technical background and tools to mitigate risks associated with exposure to PFAS-affected groundwater.Objectives:The aim was to identify challenges faced by stakeholders to extend best practices to other regions experiencing PFAS releases and to establish a framework for research strategies and best management practices.Methods and Approach:Management challenges were identified during stakeholder engagement events connecting attendees with PFAS experts in focus areas, including fate/transport, toxicology, and regulation. Review of the literature provided perspective on challenges in all focus areas. Publicly available data were used to characterize sources of PFAS impacts in groundwater and conduct a geospatial case study of potential source locations relative to drinking water aquifers in Rhode Island.Discussion:Challenges in managing PFAS impacts in drinking water arise from the large number of relevant PFASs, unconsolidated information regarding sources, and limited studies on some PFASs. In particular, there is still considerable uncertainty regarding human health impacts of PFASs. Frameworks sequentially evaluating exposure, persistence, and treatability can prioritize PFASs for evaluation of potential human health impacts. A regional case study illustrates how risk-based, geospatial methods can help address knowledge gaps regarding potential sources of PFASs in drinking water aquifers and evaluate risk of exposure.Conclusion:Lessons learned from stakeholder engagement can assist in developing strategies for management of PFASs in other regions. However, current management practices primarily target a subset of PFASs for which in-depth studies are available. Exposure to less-studied, co-occurring PFASs remains largely unaddressed. Frameworks leveraging the current state of science can be applied toward accelerating this process and reducing exposure to total PFASs in drinking water, even as research regarding health effects continues. https://doi.org/10.1289/EHP2727

Occurrence and behavior of per‐ and polyfluoroalkyl substances from aqueous film‐forming foam in groundwater systems

AbstractPer‐ and polyfluoroalkyl substances (PFAS) are fluorinated compounds and the active ingredient in aqueous film‐forming foam (AFFF). AFFF has been identified as a significant source of PFAS contamination in groundwater. PFAS are also present in many other industrial and consumer products and their manufacture and use has led to numerous contaminated sites. Human health risks have been identified with studies linking firefighter cancers to training facilities where AFFF was used. Given the widespread release of these compounds to the environment and their potential health risks, understanding their mobility characteristics is important. This article details the occurrence and behavior of these substances in groundwater systems to help guide the emerging fields of PFAS investigation and remediation. Background is presented on AFFF and PFAS source characteristics, including common industrial and consumer PFAS sources. In addition, chemical properties, sorption and retention parameters, and observed transformation properties of PFAS and related compounds are discussed. Finally, knowledge gaps are identified for future laboratory and field studies.

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.

Release of Per- and Polyfluoroalkyl Substances (PFASs) from Carpet and Clothing in Model Anaerobic Landfill Reactors.

Discarded carpet and clothing are potential sources of per- and polyfluoroalkyl substances (PFASs) in landfill leachate, but little is known about their release when disposed in landfills. The concentrations of 70 PFASs in the aqueous phase of anaerobic model landfill reactors filled with carpet or clothing were monitored under biologically active and abiotic conditions. For carpet, total PFAS release was greater in live than abiotic reactors, with an average of 8.5 nmol/L and 0.62 nmol/L after 552 days, respectively. Release in live carpet reactors was primarily due to 5:3 fluorotelomer carboxylic acid (FTCA - 3.9 nmol/L) and perfluorohexanoic carboxylic acid (PFHxA - 2.9 nmol/L). For clothing, release was more dependent on sample heterogeneity than the presence of biological activity, with 0.63, 21.7, 2.6, and 6.3 nmol/L for two live and two abiotic reactors after 519 days, respectively. Release in the clothing reactors was largely due to perfluorooctatonic carboxylic acid (PFOA), with low relative concentrations of measured biotransformation precursors (FTCAs). For carpet and clothing reactors, the majority of PFAS release was not measured until after day 100. Results demonstrate that carpet and clothing are likely sources of PFASs in landfill leachate.

Distribution and primary source analysis of per- and poly-fluoroalkyl substances with different chain lengths in surface and groundwater in two cities, North China

Per- and poly-fluoroalkyl substances (PFASs) have been widely detected in the hydrosphere. The knowledge on the distribution and composition patterns of PFAS analogues with different chain length significantly contribute to their source analysis. In the present study, a regional scale investigation of PFASs in surface river waters and adjacent ground waters was carried out in two cities of China with potential contamination, Tianjin and Weifang. A total of 31 water samples were collected, and 20 PFASs therein were measured by a high-performance liquid chromatograph–tandem mass spectrometer (HPLC–MS/MS). The possible sources of PFASs in the aquatic environment were assessed primarily by concentration patterns as well as hierarchical cluster analysis. In all 4 rivers investigated in the two cities, perfluoroalkyl carboxylic acids (PFCAs) were the dominant compounds contributing over 70% of the PFASs detected. Perfluorooctanoic acid (PFOA) was the dominant PFCA with a concentration range of 8.58–20.3ng/L in Tianjin and 6.37–25.9ng/L in Weifang, respectively. On the average, the highest concentration was observed in samples from Dagu Drainage Canal (Dagu) in Tianjin and those short-chain PFASs (C4–C6) was detected with a comparable level of the longer-chain PFASs (>C6). Specifically, perfluorobutanoic acid (PFBA) was dominant in the short-chain analogues. This indicates that a remarkably increasing input of short-chain PFASs might be related to wastewater treatment plant effluent or industrial discharges, which could be possibly due to the switch of manufacturing to short-chain products. In Weifang, precipitation and subsequent surface runoff as non-point sources could be significant inputs of PFASs into surface water while groundwater was possibly subjected to severe point sources with ∑PFASs concentration up to ~100ng/L. The inconsistent distribution patterns in groundwater suggest complicated pathways of contamination.

Distribution and sources of polyfluoroalkyl substances (PFAS) in the River Rhine watershed

The concentration profile of 40 polyfluoroalkyl substances (PFAS) in surface water along the River Rhine watershed from the Lake Constance to the North Sea was investigated. The aim of the study was to investigate the influence of point as well as diffuse sources, to estimate fluxes of PFAS into the North Sea and to identify replacement compounds of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In addition, an interlaboratory comparison of the method performance was conducted. The PFAS pattern was dominated by perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) with concentrations up to 181 ng/L and 335 ng/L, respectively, which originated from industrial point sources. Fluxes of ΣPFAS were estimated to be ∼6 tonnes/year which is much higher than previous estimations. Both, the River Rhine and the River Scheldt, seem to act as important sources of PFAS into the North Sea.