Uncovering hydrothermal treatment of per- and polyfluoroalkyl substances
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PROVIDER: S-EPMC10702917 | biostudies-literature | 2023 Feb
REPOSITORIES: biostudies-literature
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Project description:Because of environmental and health concerns, legacy per- and polyfluoroalkyl substances (PFAS) have been voluntarily phased out, and thousands of emerging PFAS introduced as replacements. Traditional analytical methods target a limited number of mainly legacy PFAS; therefore, many species are not routinely assessed in the environment. Nontargeted approaches using high-resolution mass spectrometry methods have therefore been used to detect and characterize unknown PFAS. However, their ability to elucidate chemical structures relies on generation of informative fragments, and many low concentration species are not fragmented in typical data-dependent acquisition approaches. Here, a data-independent method leveraging ion mobility spectrometry (IMS) and size-dependent fragmentation was developed and applied to characterize aquatic passive samplers deployed near a North Carolina fluorochemical manufacturer. From the study, 11 PFAS structures for various per- and polyfluorinated ether sulfonic acids and multiheaded perfluorinated ether acids were elucidated in addition to 36 known PFAS. Eight of these species were previously unreported in environmental media, and three suspected species were validated.
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Project description:The determination of gas phase thermochemical properties of per- and polyfluoroalkyl substances (PFAS) is central to understanding the long-range transport behavior of PFAS in the atmosphere. Prior gas-phase studies have reported the properties of perfluorinated sulfonic acid (PFOS) and perfluorinated octanoic acid (PFOA). Here, this study reports the gas phase enthalpies of formation of short- and long-chain PFAS and their precursor molecules determined using density functional theory (DFT) and ab initio approaches. Two density functionals, two ab initio methods and an empirical method were used to compute enthalpies of formation with the total atomization approach and an isogyric reaction. The performance of the computational methods employed in this work were validated against the experimental enthalpies of linear alkanoic acids and perfluoroalkanes. The gas-phase determinations will be useful for future studies of PFAS in the atmosphere, and the methodological choices will be helpful in the study of other PFAS.
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Project description:To investigate the effects of Perfluorononanoic Acid (PFNA) exposure to 3D cultured ovarian follicles during gonadotrophin-dependent maturation and ovulation
2025-04-07 | GSE227267 | GEO
Project description:Wastewater treatment plants generate a solid waste known as biosolids. The most common management option for biosolids is to beneficially reuse them as an agricultural amendment, but because of the risk of pathogen exposure, many regulatory bodies require pathogen reduction before biosolids reuse. Per- and polyfluoroalkyl substances (PFAS) are well documented in biosolids, but limited information is available on how biosolids treatment processes impact PFAS. Furthermore, quantification of PFAS has focused on perfluoroalkyl acids (PFAAs) which are a small fraction of thousands of PFAS known to exist. The objective of this study was to quantify 92 PFAS in biosolids collected from eight biosolids treatment facilities before and after four pathogen treatment applications: composting, heat treatment, lime treatment, and anaerobic digestion. Overall, total PFAS concentrations before and after treatment were dominated by PFAA precursor species, in particular, diPAPs which accounted for a majority of the mass of the Σ92PFAS. This differs from historic data that found PFAAs, primarily PFOS, to dominate total PFAS concentrations. Treatment options such as heat treatment and composting changed the ratio of PFAA precursors to PFAAs indicating a transformation of PFAS during treatment. This study finds that PFAA precursors are likely underrepresented by other studies and make up a larger percentage of the total PFAS concentration in biosolids than previously estimated.
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Project description:We analyzed 72 children's textile products marketed as stain-resistant from US and Canadian stores, particularly school uniforms, to assess if clothing represents a significant route of exposure to per- and polyfluoroalkyl substances (PFAS). Products were first screened for total fluorine (total F) using particle-induced γ-ray emission (PIGE) spectroscopy (n = 72), followed by targeted analysis of 49 neutral and ionic PFAS (n = 57). PFAS were detected in all products from both markets, with the most abundant compound being 6:2 fluorotelomer alcohol (6:2 FTOH). Total targeted PFAS concentrations for all products collected from both countries ranged from 0.250 to 153 000 ng/g with a median of 117 ng/g (0.0281-38 100 μg/m2, median: 24.0 μg/m2). Total targeted PFAS levels in school uniforms were significantly higher than in other items such as bibs, hats, stroller covers, and swimsuits, but comparable to outdoor wear. Higher total targeted PFAS concentrations were found in school uniforms made of 100% cotton than synthetic blends. Perfluoroalkyl acids (PFAAs) precursors were abundant in school uniforms based on the results of hydrolysis and total oxidizable precursor assay. The estimated median potential children's exposure to PFAS via dermal exposure through school uniforms was 1.03 ng/kg bw/day. Substance flow analysis estimated that ∼3 tonnes/year (ranging from 0.05 to 33 tonnes/year) of PFAS are used in US children's uniforms, mostly of polymeric PFAS but with ∼0.1 tonne/year of mobile, nonpolymeric PFAS.
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Project description:Per- and polyfluoroalkyl substances (PFAS) are widely used in commercial products such textiles, firefighting foams, and surface coatings across the globe and some PFAS are known to be bioaccumulative in aquatic species. The ultimate sink for numerous anthropogenic chemicals is the sediments in lakes, rivers, and oceans. To understand the relationship between sediment and aquatic species, a literature search was performed and biota-sediment accumulation factors (BSAFs) data for 17 taxonomic classes were assembled. The carbonyl and sulfonyl PFAS classes were relatively data rich whereas phosphate (no measurements), ether (one chemical), and fluorotelomer (limited number of chemicals) PFAS classes were data poor. Taxonomic classes of Teleostei and Clitellata had the largest BSAFs whereas Magnoliopsida and Bivalvia had the smallest BSAFs, and BSAF values >1 (kg-OC/kg-wet wt) were very rare. Across all studies, median (±standard deviation) whole-body Teleostei BSAFs for perfluorooctane sulfonic acid and perfluorooctanoic acid (kg-OC/kg-wet wt) were 0.0580 (±0.445, n = 60) and 0.00283 (±0.103,24), respectively. Laboratory-measured BSAFs were consistently larger than field-measured BSAFs, that is, 53 of 67 comparisons were larger (80%). Comparing BSAFs across taxonomic classes, 72% of the BSAFs were significantly different (α = 0.05). Comparing BSAFs within a taxonomic class, BSAFs were significantly different for 63% of the taxonomic classes. Elimination kinetics for benthic invertebrates suggests steady-state conditions might be reached in the 28-day uptake portion of a laboratory bioaccumulation test for some test species. The largest data gaps, beyond limited measurements, are understanding the effects of concentration and mixtures on bioaccumulation from sediments, quantifying the difference, if any, in BSAFs between freshwater and brackish/marine ecosystems, and models for predicting BSAFs based on concentrations in sediment. Environ Toxicol Chem 2023;42:277-295. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
| S-EPMC11519828 | biostudies-literature
Project description:Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative chemicals that can be toxic at very low levels. Many of these compounds have unusual chemical properties that can have a large impact on analytical methods intended to quantitate them. When analyzing environmental samples, concentrating extraction eluents can greatly increase the sensitivity of PFAS extraction and analysis workflows. However, data on PFAS stability when evaporated under vacuum drying conditions are lacking. In this study two common sample preparation methods were replicated (methanol or methanolic ammonium hydroxide) to determine if PFAS material would undergo any observable loss during vacuum evaporation. Standards containing 49 different analytes from 7 different PFAS classes were evaporated to dryness under vacuum either with or without heat and reconstituted using one of two methods. It was found that recovery of some classes (e.g. PFSA, PFESA, FTS) was not greatly impacted by evaporation conditions or reconstitution method. Some analytes such as the very long chain PFCAs were not affected by evaporation conditions but saw drastic differences in recovery depending on the reconstitution method. Others analytes, for example PFSAms, experienced significant loss during evaporation that could not be mitigated by the chosen reconstitution method. This difference could be due to the number of fluorines present on the compound which correlated with a compound's hydrophobicity. Due to these findings, it is recommend that researchers consider PFAS class, chain length, and fluorine number when designing concentration and reconstitution protocols for PFAS to ensure conditions are optimal for the specific analytes of interest.
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Project description:These analyses set out to evaluate changes in microRNA signatures within extracellular vesicles isolated from liver cells exposed to a mixture of PFAS.
2023-05-01 | GSE200764 | GEO
Project description:Purpose of reviewPer- and polyfluoroalkyl substances (PFAS) are a diverse class of persistent, fluorinated surfactants used widely in industrial and commercial applications with known adverse health effects. Seafood consumption is thought to be an underappreciated source of PFAS exposure in the general population. This review synthesizes the current understanding of PFAS occurrence in shellfish, a term used to describe animals such as mollusk bivalves, certain gastropods (snails), cephalopods (e.g., octopuses and squid), and crustaceans, and highlights scientific gaps relative to bioaccumulation and the protection of shellfish consumers.Recent findingsA range of sampling methodologies are used across studies, and the suite of PFAS surveyed across studies is highly variable. Concentrations of PFAS observed in shellfish vary by geographic location, shellfish species, habitat, and across PFAS compounds, and studies informing estimates of bioaccumulation of PFAS in shellfish are extremely limited at this time. This review identifies several important opportunities for researchers to standardize PFAS sampling techniques, sample preparation, and analytical methodologies to allow for better comparison of PFAS analytes both within and across future studies. Increasing the range of geographic locations where samples are collected is also a critical priority to support a greater knowledge of worldwide PFAS contamination. When put into the context of risk to consumer, concentrations of PFAS, especially PFOS, found in shellfish collected from sites containing aqueous film-forming foam (AFFF) and industrial contamination may present risks to frequent consumers. Further research is needed to protect shellfish consumers and to inform shellfish advisories and health protective policies.
| S-EPMC9841895 | biostudies-literature
Project description:Per- and polyfluoroalkyl substances (PFAS) are widely used across the globe in commercial products such textiles, firefighting foams, and surface coatings. Some PFAS, such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are known to be bioaccumulative. Numerous terrestrial ecosystems including sites near PFAS manufacturing facilities, facilities using PFAS in their manufacturing processes, firefighting training areas, landfills, and agricultural fields treated with some pesticide formulations, have been contaminated with PFAS. Earthworms reside at the base of the terrestrial food chain and to perform risk assessments at terrestrial sites contaminated with PFAS, information on the bioaccumulation of PFAS is needed. To understand the bioaccumulation of PFAS by earthworms, a literature search was performed, and biota-soil accumulation factors (BSAFs), measured in laboratory tests and at field sites contaminated with PFAS, were assembled and evaluated in this review. Based on this review, we conclude that there is enough data available for carboxylic and sulfonic acid PFAS classes to derive useful BSAFs for terrestrial risk assessments. Laboratory tests with PFOS and PFOA will be close to or at steady-state conditions with standardized testing protocols, and for the longer chain carboxylic and sulfonic acids, it is unlikely they will reach steady-state with the completion of the uptake exposure. For PFAS classes beyond the carboxylic and sulfonic acids, data are limited and performing terrestrial risk assessments with these PFAS will be difficult. Lastly, additional measurements are needed for non-acid PFAS classes as well as from field settings for all PFAS classes. Across all studies, PFOS and PFOA had average (standard deviation, count) BSAFs (kg-OC/kg-ww) of 0.167 (0.311, 60) and 0.0413 (0.175, 47), respectively.
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