Abstract  Perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), which are classified as perfluoroalkyl and polyfluoroalkyl substances (PFASs), have been widely used in industrial applications as a surface protectant. PFASs have been detected in wildlife and in humans around the globe. The purposes of this study are to develop and validate a physiologically based pharmacokinetic (PBPK) model for detecting PFNA and PFDA in male and female rats, and to apply the model to a human health risk assessment regarding the sex difference. A PBPK model of PFNA and PFDA was established based on an in vivo study in male and female rats. Analytes in biological samples (plasma, nine tissues, urine, and feces) were determined by ultra-liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS) method. PFNA and PFDA showed a gender differences in the elimination half-life and volume of distribution. The tissue-plasma partition coefficients were the highest in the liver in both male and female rats. The predicted rat plasma and urine concentrations simulated and fitted were in good agreement with the observed values. The PBPK models of PFNA and PFDA in male and female rats were then extrapolated to a human PBPK model based on human physiological parameters. The external doses were calculated at 3.35 ng/kg/day (male) and 17.0 ng/kg/day (female) for PFNA and 0.530 ng/kg/day (male) and 0.661 ng/kg/day (female) for PFDA. Human risk assessment was estimated using Korean biomonitoring values considering the gender differences. This study provides valuable insight into human health risk assessment regarding PFNA and PFDA exposure.

Abstract  The spatial and temporal distribution of per- and polyfluoroalkyl substances (PFASs) in the open Western Mediterranean Sea waters was investigated in this study for the first time. In addition to surface water samples, a deep water sample (1390 m depth) collected in the center of the western basin was analyzed. Perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were detected in all samples and were the dominant PFASs found. The sum of PFAS concentrations (ΣPFASs) ranged 246-515 pg/L for surface water samples. PFASs in surface water had a relatively homogeneous distribution with levels similar to those previously measured in the Atlantic near the Strait of Gibraltar, in water masses feeding the inflow to the Mediterranean Sea. Higher concentrations of PFHxA, PFHpA and PFHxS were, however, found in the present study. Inflowing Atlantic water and river/coastal discharges are likely the major sources of PFASs to the Western Mediterranean basin. Slightly lower (factor of 2) ΣPFASs was found in the deep water sample (141 pg/L). Such a relatively high contamination of deep water is likely to be linked to recurring deep water renewal fed by downwelling events in the Gulf of Lion and/or Ligurian Sea.

Abstract  Decomposition of perfluorinated chemicals is of significant interest in both scientific and industrial perspectives. Here, we report the decomposition of perfluorooctanoic acid (PFOA) under sonication-assisted photocatalysis by utilizing commercial TiO(2) (RdH) and home-made TiO(2) (sol-gel) as photocatalysts at ambient temperature, pressure and near neutral pH with the irradiation of 254nm UV light. PFOA was decomposed into fluoride ions and to several perfluorinated carboxylic acids (PFCAs) with a shorter carbon chain length such as perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropropanoic acid (PFPA), and trifluoroacetic acid (TFA). The efficiency of sonication-assisted photocatalysis was found to be 64%. In all the cases, higher efficiencies were obtained when sol-gel TiO(2) was used as a photocatalyst than the commercial RdH TiO(2) catalyst. The specific surface area is three times higher for sol-gel TiO(2) than commercial RdH TiO(2) and appears to be the probable reason for the observed differences in the corresponding efficiencies. It is also interesting to note that pH plays a determining role in the decomposition of PFOA and correspondingly photocatalyses were carried out under different controlled pH. Perfluoroalkyl radicals are presumably oxidized by superoxide and hydroxyl radicals generated during the TiO(2)-mediated photocatalysis at pH 4 and 10, respectively. The role of sonication in sonication-assisted photocatalysis was construed to be an aid to photocatalysis than a tool itself. Sonication enhances photocatalysis through physical dispersion of TiO(2) and eases mass transfer which keeps on rejuvenating the TiO(2) surface.

Abstract  The aim of this study was to investigate 12 perfluorinated compounds (PFCs) including perfluorinated carboxylates (C4-C12) and perfluorinated alkyl sulfonates (C4, C6, and C8) in river and seawater samples to determine contamination levels in the aquatic environment of Hyogo prefecture, Japan. High levels of perfluorohexanoic acid (PFHxA; 2300-16,000 ng/L) were detected in the Samondogawa River at Tatsumi Bridge downstream of a PFC production facility; this location also had the highest mass flow rate of PFCs (3900-29,000 kg/y). Widespread contamination of coastal waters was confirmed with PFHxA as the dominant compound. Perfluorooctanoic acid was also prevalent in coastal waters. The concentration of PFHxA in coastal seawater and the distance from the mouth of the Samondogawa River were inversely related. This discharge of high concentrations of PFHxA from the Samondogawa River may have affected concentrations of PFCs in Osaka Bay.

Abstract  To efficiently remove and recover perfluorinated compounds (PFCs) such as perfiuorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) from water, surface-tethered beta-cyclodextrins (CDs) on the surface of polystyrene (PS) particles (PS-beta-CDs) were prepared. The PS-beta-CDs with a 36% beta-CD content showed high adsorption capability against these PFCs from water via inclusion complex formation. The perfluorocarboxylic acids (PFCAs) adsorbed onto PS-beta-CDs were easily and quantitatively recovered by washing with acetone.

Abstract  BACKGROUND: A new method for the determination of four perfluoroalkyl carboxylic acids (from C5 to C8) and perfluorooctane sulfonate in human milk samples using stir-bar sorptive extraction-ultra-HPLC-MS/MS has been accurately optimized and validated.

METHODOLOGY: Polydimethylsiloxane and polyethyleneglycol modified silicone materials were evaluated.

DISCUSSION: Overall, polyethyleneglycol led to a better sensitivity. After optimizing experimental variables, the method was validated reaching detection limits in the range of 0.05-0.20 ng ml(-1); recovery rates from 81 to 105% and relative standard deviations fewer than 13% in all cases. The method was applied to milk samples from five randomly selected women. All samples were positive for at least one of the target compounds with concentrations ranging between 0.8 and 6.6 ng ml(-1), being the most abundant perfluorooctane sulfonate.

Abstract  In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF2 > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF2 > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples.

Abstract  This study demonstrated the 10-year trend of 13 perfluoroalkyl substances (PFASs) serum levels among 786 adults living in Seoul, Korea. PFAS levels gradually increased from 2006 to 2013, decreasing thereafter. We found that PFAS levels were higher in male than in female participants and were positively correlated with age. PFASs were not significantly correlated with body mass index, although we observed positive correlations with total cholesterol, low-density lipoprotein cholesterol, and triglycerides and negative correlations with high-density lipoprotein cholesterol. Uric acid and free thyroxine (fT4) also showed positive correlations with major congeners while correlations between thyroid stimulating hormone and PFASs were inconsistent. We demonstrated significant correlations between fT4 and perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS), and perfluorodecanoic acid (PFDA). There were significant differences in PFHxS and perfluorododecanoic acid (PFDoDA) levels between participants with and without diabetes. Furthermore, principal component analysis suggested possible differences in disease manifestation based on the congener distribution of PFASs. This study is the first study of temporal trends of 13 PFAS congeners in serum samples obtained from the Korean general population; it is currently longest and largest scale study of this type.

Abstract  Polyfluorinated compounds (PFCs) are authorized for use as greaseproofing agents in food contact paper. As C8-PFCs (8-carbons) are known to accumulate in tissues, shorter-chain C6-PFCs (6-carbons) have replaced C8-PFCs in many food contact applications. However, the potential of C6-PFCs for human biopersistence has not been fully evaluated. For the first time, we provide internal exposure estimates to key metabolites of 6:2 fluorotelomer alcohol (6:2 FTOH), a monomeric component of C6-PFCs, to extend our understanding of exposure beyond estimates of external exposure. Pharmacokinetic data from published rat and human studies on 6:2 FTOH were used to estimate clearance and area under the curve (AUC) for its metabolites: 5:3 fluorotelomer carboxylic acid (5:3 A), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA). Internal exposure to 5:3 A was the highest of evaluated metabolites across species and it had the slowest clearance. Additionally, 5:3 A clearance decreased with increasing 6:2 FTOH exposure. Our analysis provides insight into association of increased internal 5:3 A exposure with high biopersistence potential of 6:2 FTOH. Our results identify 5:3 A as an important biomarker of internal 6:2 FTOH exposure for use in biomonitoring studies, and are potentially useful for toxicological assessment of chronic dietary 6:2 FTOH exposure.

Abstract  This study aimed at bridging knowledge gaps regarding the land-sea transport of per- and polyfluoroalkyl substances (PFASs) through riverine discharge into coastal waters. The present survey was conducted in the Gironde estuary (southwestern France) where PFASs were ubiquitously detected albeit at low levels. Emerging PFASs such as fluorotelomer sulfonates or polyfluoroalkyl phosphate diesters accounted for a relatively minor proportion of ∑PFASs, while perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorohexanoate were the predominant congeners. Multiple linear regressions provided insights into the relative influence of factors controlling PFAS sediment levels. In that respect, the organic carbon fraction (strongly correlated to sediment grain size) appeared as a more important controlling factor than black carbon or distance from upstream sources for long-chain perfluoroalkyl acids. In the maximum turbidity zone (suspended solids up to 2600 mg L-1), the particle-associated fraction was almost consistently >50% for long-chain perfluoroalkyl carboxylates and sulfonates (≥C8 and ≥ C6, respectively). Empirical models of KDpartitioning coefficients were derived by integrating, for the first time, both particle-concentration and salting-out effects. These results represent significant progress toward the development of numerical transport models integrating both PFAS partitioning and 3D-hydrosedimentary dynamics, with a view to estimate PFAS mass budgets at the land-sea interface.

Abstract  The historical use of aqueous film forming foams (AFFF) containing perfluoroalkyl substances (PFASs) for firefighting and training activities has resulted in groundwater contamination. The competitive adsorption of PFASs and the effect of co-existing compounds on the removal of PFASs by anion-exchange resins were studied in this study. Perfluorohexane sulfonate (PFHxS) was selected as the representative PFAS, and resin IRA910 was found to be effective for PFHxS removal. When PFHxS was co-removed with other PFASs in bisolute system, it replaced the adsorbed PFASs with shorter C-F chains on the IRA910, while perfluorooctanesulfonate (PFOS) was not replaced by PFHxS. The competitive adsorption among PFASs decreased in the order of PFOS?>?PFHxS?>?PFOA?>?PFBS>PFHxA?>?PFBA, closely related to the hydrophobicity and functional groups of PFASs. The nonionic organic compounds could not interfere with the PFHxS removal, while ionic ones can reduce the sorption amount and their influence to the sorption of PFHxS was concentration dependent. The presence of inorganic anions slightly decreased the removal efficiency of PFHxS and the influence of different inorganic anions was similar due to multiple effects including competitive anion, screening effect, and salting-out effect in the adsorption process.

Abstract  Perfluorochemicals (PFC's) are widely spread in the environment and have been detected in blood of wildlife and humans world-wide. Recently, various toxic effects of PFC's in laboratory rats have been demonstrated, resulting in increased government concerns regarding the presence of PFC's in the environment and the implications they have on human health. In the last decade, various analytical methods have been developed for the analysis of PFC's in different matrices whereby the majority of methods have utilised liquid chromatography coupled with mass spectrometry (LC-MS). Here we describe an optimized method for the quantitation of PFC's, including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), in food packaging, polytetrafluoroethylene (PTFE) sealant tape and drinking water. The method involved PFC's extraction via off-line SPE followed by separation using reversed-phase liquid chromatography on a Phenyl-Hexyl column coupled with ion-trap (IT) mass spectrometric detection. The optimized approach minimized ion-suppression effects commonly seen with conventional elution buffers, improving detection limits down to 25 pg/mL and allowed effective quantitation down to 50 pg/mL for PFOA and PFOS. The optimized LC-MS method detected PFOA and other PFC's in microwave popcorn packaging and PFOA in PTFE sealant tape in the low μg/kg. In all samples, PFOS was not detected.

Abstract  The potential negative effects of perfluoroalkyl substances (PFASs) discharged into aquatic environments are drawing increasing attention. However, little research has been undertaken on PFASs in wastewater from electroplating industrial parks. In this study, the concentration profiles and geographical distribution of 11 PFASs were analyzed in water samples collected from different production workshops and an artificial landscaped lake. The total concentrations of PFASs (Σ11PFASs) at various points in the production drainage system range from 229.5 to 5410.6 ng/L, and are mainly contributed by nickel plating, pickling, and the cyanide bright silver plating procedure, which correspond to cyanide-containing and acid-alkali wastewater conditioning tanks. Wastewater treatment by oxidation and precipitation removed 52.6% and 20% of PFASs, respectively. Σ11PFASs in effluents is about 538 ng/L, which consists of perfluorooctanoic acid (PFOA, 430.5 ng/L), followed by perfluorooctane sulfonate (PFOS, 35.27 ng/L), perfluorohexane sulfonate (PFHxS, 28.05 ng/L), and perfluorohexanoic acid (PFHxA, 18.3 ng/L). Principal component analysis suggests that the Σ11PFASs in electroplating wastewater is very high and short-chain (C4-C8) PFASs have high detection and contribution rates. As a result, much attention should be paid to the increase in short-chain substitution effects and pollution around the factory area.

Abstract  Fluorochemicals have its applications in many fields, as in firefighting, electroplating and electronics industries. A number of novel approaches using fluorochemicals in textile processing are a portent area for better marketing of textile goods. Value added finishing of textiles is a new development in textiles processing and these fluorochemical finishes impart water repellency, oil repellency, soil repellency giving value addition to the textile substrate. Application of the fluorochemical finish has been found to be versatile in nature and can also be used to make fluoropolymer coatings and products that resist heat, oil, stains, grease, etc. In the recent times, C8 carbon atoms which was found to be carcinogenic in nature has been replaced by C6 and C4. C6 chemistry produces a byproduct called PFHA (perfluorohexanoic acid), which is supposed to be 40 times less bio accumulative than PFOA and found to be environment friendly. © 2018 Elsevier Ltd. All rights reserved.

Abstract  Objective: To explore the method to construct the progesterone receptor (PR)-superparamagnetic iron oxide (SPIO)-poly lactic-co-glycolic acid (PLGA) and perfluorohexane (PFP) molecular probe (PR-s-PFP/PLGA), and to investigate its targeted possibility of binding the breast cancer cells in vitro. Methods: The s-PFP/PLGA nanoparticles were prepared and the diameter and average potential of s-PFP/PLGA nanoparticles were detected. Cytotoxicity experiment was used to compare the relative proliferation rates (RGR) of cells with different concentrations of s-PFP/PLGA. The magnetic resonance imaging (MRI), photoacoustic imaging (PAI) and ultrasound imaging of s-PFP/PLGA nanoparticles were detected, and the echo intensity of s-PFP/PLGA nanoparticles was observed by high intensity focused ultrasound (HIFU) invitro. The PR-s-PFP/PLGA probe was prepared by carbodiimide method. The breast cancer cell line T-47d with high expression of PR was cultured in vitro. The T-47d cells with DiO green fluorescence were divided into targeted imaging agent group, non-targeted group and blank control group. The binding of the probe to the cells in various groups was observed. Results: The s-PFP/PLGA nanoparticles were spherical under transmission electron microscope (TEM). The SPIO particles were evenly distributed on the shell, the average particle size was (738. 5 + 181. 2) nm and the average potential was (-15. 8 + 5. 7) mV, and the obvious photoacoustic signals were found. The ultrasound imaging of s-PFP/PLGA nanoparticles in vitro showed a punctate high-level echo, and the echo intensity was enhanced after HIFU irradiation. With the increasing of iron concentrations, the MRI signals showed a increasing trend in T1W1. Under laser scanning confocal microscope, the s-PFP/PLGA nanoparticles, which was phagocytized by T-47d cells, emitted red fluorescence. Conclusion; PR-SPIO-PLGA has excellent physicochemical properties, good stability and strong targeting effect on the cancer cells. © 2018 Jilin University Press.All Rights Reserved.

Abstract  This chapter discusses the physical and chemical properties of perfluoroalkyl compounds. Some of the perfluoroalkyl compounds includes: perfluoro butyl sulfonate (PFBS), perfluorobutyrate (PFBA), perfluorohexane sulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluoroheptanoate (PFHpA), and perfluorooctane sulfonate (PFOS). It is believed that exposure to PFBS can result in acute effects, including changes in blood chemistry, hepatotoxicity, and nephrotoxicity. PFBA can result in acute effects, including changes in blood chemistry, hepatotoxicity, and thyroid dysfunction. Inhalation or dermal contact with PFBA can result in respiratory tract and skin irritation. Exposure to PFHxS was found to result in decreased body weight, decreased cholesterol levels, and increased prothrombin in rats. Some perfluoroalkyl chemicals, including PFHpA, have been linked to chronic effects associated with the liver, thyroid, and kidneys. Workers in direct or indirect contact may be at risk for PFUnA exposure. Inhalation and dermal contact are the most probable routes of exposure with ingestion not being likely. © 2015 by John Wiley & Sons, Inc. All rights reserved.

Abstract  The global problem of groundwater being contaminated with per- and polyfluoroalkyl substances (PFASs) originating from highly contaminated soils has created a need to remediate these locations. In situ immobilisation of PFASs in soil by applying sorbents is often a preferred low-cost technique to reduce their mobility and leaching to groundwater, but the long-term efficacy of sorbents has not yet been investigated. In this study, the longevity of remediation of two different soils by two common sorbents (RemBind®, and pulverized activated carbon, Filtrasorb™ 400) was assessed. Regulatory agencies often rely on standardised leaching procedures to assess the risk of contaminant mobility in soils. Hence, the Australian Standard Leaching Procedure and the U.S. EPA Leaching Environmental Assessment Framework were applied to quantify the desorption/leaching of a wide range of PFASs from unremediated and remediated soils under a range of pH conditions (pH 2 to 12). Ease of desorption and subsequent leaching from the unremediated soils was related to C-chain length; while short-chain PFASs were easily desorbed and leached, long-chain PFASs were more difficult to desorb. Desorption of long-chain PFASs was also pH dependent in unremediated soils, with desorption being greater at high pH. Both sorbents retained PFASs strongly in the remediated soils (> 99% for most PFASs) across a broad range of pH conditions, with only small differences between the sorbents in terms of efficacy. Both sorbents showed better retention of PFASs under low pH conditions. Remediation of PFAS-contaminated soils with these sorbents could be considered robust and durable in terms of changes in soil pH, with little risk of subsequent PFASs desorption under normal environmental pH conditions. Ultimately, to give regulators and site owners the greatest level of confidence that immobilisation is stable for the longer term, it should also be tested under repeated cycles of leaching and under different conditions. © 2020 Elsevier B.V.

Abstract  The development of high-throughput screening methodologies may decrease the need for laboratory animals for toxicity testing. Here, we investigate the potential of assessing immunotoxicity with high-throughput screening data from the U.S. Environmental Protection Agency ToxCast program. As case studies, we analyzed the most common chemicals added to food as well as per-and polyfluoroalkyl substances (PFAS) shown to migrate to food from packaging materials or processing equipment. The antioxidant preservative tert-butylhydroquinone (TBHQ) showed activity both in ToxCast assays and in classical immunological assays, suggesting that it may affect the immune response in people. From the PFAS group, we identified eight substances that can migrate from food contact materials and have ToxCast data. In epidemiological and toxicological studies, PFAS suppress the immune system and decrease the response to vaccination. However, most PFAS show weak or no activity in immune-related ToxCast assays. This lack of concordance between toxicological and high-throughput data for common PFAS indicates the current limitations of in vitro screening for analyzing immunotoxicity. High-throughput in vitro assays show promise for providing mechanistic data relevant for immune risk assessment. In contrast, the lack of immune-specific activity in the existing high-throughput assays cannot validate the safety of a chemical for the immune system. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Abstract  Per- and polyfluoroalkyl substances (PFASs), including fluorotelomer alcohols (FTOHs), perfluoroalkyl sulfonamidoethanols (FOSEs), and perfluoroalkyl sulfonamides (FOSAs), were assessed in 61 residential indoor air and 15 personal air samples collected in Oslo area, Norway. FTOHs were detected in all samples, and the median concentrations in residential indoor air were 2970, 10400, and 3120 pg m-3 for 6:2, 8:2, and 10:2 FTOH, respectively. This is similar to or higher than previously reported in studies from the same geographical area and worldwide. FOSEs and FOSAs were detected in 49-70% and 7-13% of the residential indoor air samples, respectively. The median FTOH concentrations observed in personal air were 1970, 7170, and 1590 pg m-3 for 6:2, 8:2, and 10:2 FTOH, respectively, which is 30 to 50% lower than the median concentrations in residential indoor air. No FOSEs or FOSAs were detected above the method detection limit (MDL) in the personal air samples. Intakes of perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), and perfluorooctyl sulfonate (PFOS) through inhalation and biotransformation of PFAS precursors in air were estimated. Median intakes of 1.7, 0.17, 5.7, 0.57, 1.8, 0.18, and 2.3 pg kg bw-1 day-1 were obtained in residential indoor air, while 1.0, 0.10, 3.3, 0.33, 0.88, and 0.09 pg kg bw-1 day-1 were found in personal air for PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, and PFOS, respectively. The median PFOA intakes from residential indoor air (5.7 pg kg bw-1 day-1) and personal air (3.3 pg kg bw-1 day-1) were both around 5 orders of magnitude lower than the tolerable daily intake (TDI) reported by the European Food Safety Authority (EFSA).

Abstract  A framework for characterizing per- and polyfluoroalkyl substances (PFASs) in life cycle impact assessment (LCIA) is proposed. Thousands of PFASs are used worldwide, with special properties imparted by the fluorinated alkyl chain. Our framework makes it possible to characterize a large part of the family of PFASs by introducing transformation fractions that translate emissions of primary emitted PFASs into the highly persistent terminal degradation products: the perfluoroalkyl acids (PFAAs). Using a PFAA-adapted characterization model, human toxicity as well as marine and freshwater aquatic ecotoxicity characterization factors are calculated for three PFAAs, namely perfluorooctanoic acid (PFOA) perfluorohexanoic acid (PFHxA) and perfluorobutanesulfonic acid (PFBS). The model is evaluated to adequately capture long-term fate, where PFAAs are predicted to accumulate in open oceans. The characterization factors of the three PFAAs are ranked among the top 5% for marine ecotoxicity, when compared to 3104 chemicals in the existing USEtox results databases. Uncertainty analysis indicates potential for equally high ranks for human health impacts. Data availability constitutes an important limitation creating uncertainties. Even so, a life cycle assessment (LCA) case study illustrates practical application of our proposed framework, demonstrating that even low emissions of PFASs can have large effects on LCA results.

Abstract  6:2 Fluorotelomer alcohol (6:2 FTOH) is a short-chain polyfluoroalkyl substance (PFAS) in polymeric PFAS used in fast food packaging and stain- and water-resistant textiles and may be degradation products of some components of aqueous film-forming foams (AFFF). The general population is exposed to 6:2 FTOH by inhalation of evaporates from treated surfaces or ambient concentrations in air, ingestion of indoor dust, or ingestion of food packaged in materials containing PFAS. Although exposure to 6:2 FTOH is pervasive, little is known concerning human health effects of this compound. Some published risk assessments have assumed that perfluorohexanoic acid (PFHxA), a metabolite of 6:2 FTOH, adequately models the human health effects of 6:2 FTOH. Recently identified studies conducted with 6:2 FTOH and its metabolite, 5:3 acid, have provided information that enables comparison of the toxicological profiles of PFHxA and 6:2 FTOH. This article summarizes a comparative analysis of the toxicological effects of PFHxA and 6:2 FTOH in rodents to determine whether data for PFHxA adequately models potential hazards of 6:2 FTOH exposure. Our analysis demonstrates that 6:2 FTOH is significantly more toxic than PFHxA. Use of toxicological studies conducted with PFHxA to assess 6:2 FTOH exposure may significantly underestimate human health risk.

Abstract  Advanced oxidation and reduction processes have been intensively investigated as potential methods to promote the decomposition of perfluoroalkyl substances (PFASs). However, extreme operational conditions such as highly acidic pH, high temperature, and high pressure are required to promote degradation reactions, which makes these technologies costly and less feasible for full-scale applications. The objective of this study was to evaluate the effectiveness of zero-valent iron (ZVI) alone and a mixture of ZVI and biochar (ZVI + BC) for removal of seven target PFASs from water under ambient environmental conditions. Target PFASs included three perfluoroalkyl carboxylic acids (PFCAs) [perfluorooctanoic acid (PFOA, C8-PFCA), perfluoroheptanoic acid (C7-PFCA), and perfluorohexanoic acid (C6-PFCA)] and four perfluoroalkyl sulfonic acids (PFSAs) [perfluorooctane sulfonic acid (PFOS, C8-PFSA), perfluoroheptane sulfonic acid (C7-PFSA), perfluorohexane sulfonic acid (C6-PFSA), and perfluorobutane sulfonic acid (C4-PFSA)]. Batch test results show that PFSAs (up to 94% removal) were more effectively removed than PFCAs (up to 60% removal) when utilizing either ZVI or (ZVI + BC). About 20-60% of input PFOA (~18,550 μg L-1) and 90-94% of input PFOS (~18,580 μg L-1) were removed by ZVI alone or the mixture of (ZVI + BC). The removal efficiencies of PFCAs and PFSAs by reactive media increased with increasing chain length, from 0 to 17% for short-chain PFCAs (C6-C7) and 20 to 70% for short-chain PFSAs (C4-C7). About 5-10% of input PFOA and PFOS was partially defluorinated by ZVI alone as indicated by F- release; however, the defluorination efficiency may be underestimated due to the sorption of F- by the reactive media. Overall, the reactive mixture (ZVI + BC) may be an effective and environmentally sustainable material for removing PFASs from water under ambient environmental conditions.