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Lin HC, Sakolish C, Moyer HL, Carmichael PL, Baltazar MT, Ferguson SS, Stanko JP, Hewitt P, Rusyn I, Chiu WA. An in vitro-in silico workflow for predicting renal clearance of PFAS. Toxicol Appl Pharmacol 2024; 489:117015. [PMID: 38917890 DOI: 10.1016/j.taap.2024.117015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 06/27/2024]
Abstract
Per- and poly-fluoroalkyl substances (PFAS) have a wide range of elimination half-lives (days to years) in humans, thought to be in part due to variation in proximal tubule reabsorption. While human biomonitoring studies provide important data for some PFAS, renal clearance (CLrenal) predictions for hundreds of PFAS in commerce requires experimental studies with in vitro models and physiologically-based in vitro-to-in vivo extrapolation (IVIVE). Options for studying renal proximal tubule pharmacokinetics include cultures of renal proximal tubule epithelial cells (RPTECs) and/or microphysiological systems. This study aimed to compare CLrenal predictions for PFAS using in vitro models of varying complexity (96-well plates, static 24-well Transwells and a fluidic microphysiological model, all using human telomerase reverse transcriptase-immortalized and OAT1-overexpressing RPTECs combined with in silico physiologically-based IVIVE. Three PFAS were tested: one with a long half-life (PFOS) and two with shorter half-lives (PFHxA and PFBS). PFAS were added either individually (5 μM) or as a mixture (2 μM of each substance) for 48 h. Bayesian methods were used to fit concentrations measured in media and cells to a three-compartmental model to obtain the in vitro permeability rates, which were then used as inputs for a physiologically-based IVIVE model to estimate in vivo CLrenal. Our predictions for human CLrenal of PFAS were highly concordant with available values from in vivo human studies. The relative values of CLrenal between slow- and faster-clearance PFAS were most highly concordant between predictions from 2D culture and corresponding in vivo values. However, the predictions from the more complex model (with or without flow) exhibited greater concordance with absolute CLrenal. Overall, we conclude that a combined in vitro-in silico workflow can predict absolute CLrenal values, and effectively distinguish between PFAS with slow and faster clearance, thereby allowing prioritization of PFAS with a greater potential for bioaccumulation in humans.
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Affiliation(s)
- Hsing-Chieh Lin
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Courtney Sakolish
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Haley L Moyer
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Paul L Carmichael
- Unilever Safety and Environmental Assurance Centre, Bedfordshire MK44 1LQ, UK
| | - Maria T Baltazar
- Unilever Safety and Environmental Assurance Centre, Bedfordshire MK44 1LQ, UK
| | - Stephen S Ferguson
- Division of Translational Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Jason P Stanko
- Division of Translational Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC 27709, USA
| | - Philip Hewitt
- Chemical and Preclinical Safety, Merck Healthcare KGaA, 64293 Darmstadt, Germany
| | - Ivan Rusyn
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Weihsueh A Chiu
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
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2
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Marumure J, Simbanegavi TT, Makuvara Z, Karidzagundi R, Alufasi R, Goredema M, Gufe C, Chaukura N, Halabowski D, Gwenzi W. Emerging organic contaminants in drinking water systems: Human intake, emerging health risks, and future research directions. CHEMOSPHERE 2024; 356:141699. [PMID: 38554874 DOI: 10.1016/j.chemosphere.2024.141699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/24/2024] [Accepted: 03/11/2024] [Indexed: 04/02/2024]
Abstract
Few earlier reviews on emerging organic contaminants (EOCs) in drinking water systems (DWS) focused on their detection, behaviour, removal and fate. Reviews on multiple exposure pathways, human intake estimates, and health risks including toxicokinetics, and toxicodynamics of EOCs in DWS are scarce. This review presents recent advances in human intake and health risks of EOCs in DWS. First, an overview of the evidence showing that DWS harbours a wide range of EOCs is presented. Multiple human exposure to EOCs occurs via ingestion of drinking water and beverages, inhalation and dermal pathways are discussed. A potential novel exposure may occur via the intravenous route in dialysis fluids. Analysis of global data on pharmaceutical pollution in rivers showed that the cumulative concentrations (μg L-1) of pharmaceuticals (mean ± standard error of the mean) were statistically more than two times significantly higher (p = 0.011) in South America (11.68 ± 5.29), Asia (9.97 ± 3.33), Africa (9.48 ± 2.81) and East Europe (8.09 ± 4.35) than in high-income regions (2.58 ± 0.48). Maximum cumulative concentrations of pharmaceuticals (μg L-1) decreased in the order; Asia (70.7) had the highest value followed by South America (68.8), Africa (51.3), East Europe (32.0) and high-income regions (17.1) had the least concentration. The corresponding human intake via ingestion of untreated river water was also significantly higher in low- and middle-income regions than in their high-income counterparts. For each region, the daily intake of pharmaceuticals was highest in infants, followed by children and then adults. A critique of the human health hazards, including toxicokinetics and toxicodynamics of EOCs is presented. Emerging health hazards of EOCs in DWS include; (1) long-term latent and intergenerational effects, (2) the interactive health effects of EOC mixtures, (3) the challenges of multifinality and equifinality, and (4) the Developmental Origins of Health and Disease hypothesis. Finally, research needs on human health hazards of EOCs in DWS are presented.
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Affiliation(s)
- Jerikias Marumure
- Department of Physics, Geography and Environmental Science, School of Natural Sciences, Great Zimbabwe University, Masvingo, Zimbabwe; Department of Life and Consumer Sciences, School of Agriculture and Life Sciences, College of Agriculture and Environmental Sciences, University of South Africa, South Africa
| | - Tinoziva T Simbanegavi
- Department of Soil Science and Environment, Faculty of Agriculture, Environment, and Food Systems, University of Zimbabwe, P. O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Zakio Makuvara
- Department of Physics, Geography and Environmental Science, School of Natural Sciences, Great Zimbabwe University, Masvingo, Zimbabwe; Department of Life and Consumer Sciences, School of Agriculture and Life Sciences, College of Agriculture and Environmental Sciences, University of South Africa, South Africa
| | - Rangarirayi Karidzagundi
- Materials Development Unit, Zimbabwe Open University, P.O. Box MP1119 Mount Pleasant, Harare, Zimbabwe
| | - Richwell Alufasi
- Biological Sciences Department, Bindura University of Science Education, 741 Chimurenga Road, Off Trojan Road, P. Bag 1020, Bindura, Zimbabwe
| | - Marvelous Goredema
- Biological Sciences Department, Bindura University of Science Education, 741 Chimurenga Road, Off Trojan Road, P. Bag 1020, Bindura, Zimbabwe
| | - Claudious Gufe
- Department of Veterinary Technical Services, Central Veterinary Laboratories, Box CY55, 18A Borrowdale Road, Harare, Zimbabwe
| | - Nhamo Chaukura
- Department of Physical and Earth Sciences, Sol Plaatje University, Kimberley, 8301, South Africa
| | - Dariusz Halabowski
- University of Lodz, Faculty of Biology and Environmental Protection, Department of Ecology and Vertebrate Zoology, Lodz, Poland
| | - Willis Gwenzi
- Currently: Biosystems and Environmental Engineering Research Group, 380, New Adylin, Westgate, Harare, Zimbabwe; Formerly: Alexander von Humboldt Fellow & Guest/Visiting Professor, Grassland Science and Renewable Plant Resources, Faculty of Organic Agricultural Sciences, Universität Kassel, Steinstraße 19, D-37213, Witzenhausen, Germany; Formerly: Alexander von Humboldt Fellow and Guest Professor, Leibniz-Institut für Agrartechnik und Bioökonomie e.V. (ATB), Max-Eyth-Allee 100, D-14469 Potsdam, Germany.
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3
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Su A, Cheng Y, Zhang C, Yang YF, She YB, Rajan K. An artificial intelligence platform for automated PFAS subgroup classification: A discovery tool for PFAS screening. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171229. [PMID: 38402985 DOI: 10.1016/j.scitotenv.2024.171229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/27/2024] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Since structural analyses and toxicity assessments have not been able to keep up with the discovery of unknown per- and polyfluoroalkyl substances (PFAS), there is an urgent need for effective categorization and grouping of PFAS. In this study, we presented PFAS-Atlas, an artificial intelligence-based platform containing a rule-based automatic classification system and a machine learning-based grouping model. Compared with previously developed classification software, the platform's classification system follows the latest Organization for Economic Co-operation and Development (OECD) definition of PFAS and reduces the number of uncategorized PFAS. In addition, the platform incorporates deep unsupervised learning models to visualize the chemical space of PFAS by clustering similar structures and linking related classes. Through real-world use cases, we demonstrate that PFAS-Atlas can rapidly screen for relationships between chemical structure and persistence, bioaccumulation, or toxicity data for PFAS. The platform can also guide the planning of the PFAS testing strategy by showing which PFAS classes urgently require further attention. Ultimately, the release of PFAS-Atlas will benefit both the PFAS research and regulation communities.
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Affiliation(s)
- An Su
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Pharmaceutical Engineering of Zhejiang Province, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China.
| | - Yingying Cheng
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China; Key Laboratory of Pharmaceutical Engineering of Zhejiang Province, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, PR China
| | - Chengwei Zhang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yun-Fang Yang
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China
| | - Yuan-Bin She
- State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Key Laboratory of Green Chemistry-Synthesis Technology of Zhejiang Province, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, China.
| | - Krishna Rajan
- Department of Materials Design and Innovation, University at Buffalo, Buffalo, NY 14260-1660, United States.
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Judson RS, Smith D, DeVito M, Wambaugh JF, Wetmore BA, Paul Friedman K, Patlewicz G, Thomas RS, Sayre RR, Olker JH, Degitz S, Padilla S, Harrill JA, Shafer T, Carstens KE. A Comparison of In Vitro Points of Departure with Human Blood Levels for Per- and Polyfluoroalkyl Substances (PFAS). TOXICS 2024; 12:271. [PMID: 38668494 PMCID: PMC11053643 DOI: 10.3390/toxics12040271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/29/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are widely used, and their fluorinated state contributes to unique uses and stability but also long half-lives in the environment and humans. PFAS have been shown to be toxic, leading to immunosuppression, cancer, and other adverse health outcomes. Only a small fraction of the PFAS in commerce have been evaluated for toxicity using in vivo tests, which leads to a need to prioritize which compounds to examine further. Here, we demonstrate a prioritization approach that combines human biomonitoring data (blood concentrations) with bioactivity data (concentrations at which bioactivity is observed in vitro) for 31 PFAS. The in vitro data are taken from a battery of cell-based assays, mostly run on human cells. The result is a Bioactive Concentration to Blood Concentration Ratio (BCBCR), similar to a margin of exposure (MoE). Chemicals with low BCBCR values could then be prioritized for further risk assessment. Using this method, two of the PFAS, PFOA (Perfluorooctanoic Acid) and PFOS (Perfluorooctane Sulfonic Acid), have BCBCR values < 1 for some populations. An additional 9 PFAS have BCBCR values < 100 for some populations. This study shows a promising approach to screening level risk assessments of compounds such as PFAS that are long-lived in humans and other species.
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Affiliation(s)
- Richard S. Judson
- US Environmental Protection Agency, Research Triangle Park, NC 27711, USA; (D.S.); (M.D.); (J.F.W.); (B.A.W.); (K.P.F.); (G.P.); (R.S.T.); (R.R.S.); (J.H.O.); (S.D.); (S.P.); (J.A.H.); (T.S.); (K.E.C.)
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5
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Villeneuve DL, Blackwell BR, Bush K, Harrill J, Harris F, Hazemi M, Le M, Stacy E, Flynn KM. Transcriptomics-Based Points of Departure for Daphnia magna Exposed to 18 Per- and Polyfluoroalkyl Substances. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2024. [PMID: 38450772 DOI: 10.1002/etc.5838] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/08/2024] [Accepted: 01/27/2024] [Indexed: 03/08/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) represent a large group of contaminants of concern based on their widespread use, environmental persistence, and potential toxicity. Many traditional models for estimating toxicity, bioaccumulation, and other toxicological properties are not well suited for PFAS. Consequently, there is a need to generate hazard information for PFAS in an efficient and cost-effective manner. In the present study, Daphnia magna were exposed to multiple concentrations of 22 different PFAS for 24 h in a 96-well plate format. Following exposure, whole-body RNA was extracted and extracts, each representing five exposed individuals, were subjected to RNA sequencing. Following analytical measurements to verify PFAS exposure concentrations and quality control on processed cDNA libraries for sequencing, concentration-response modeling was applied to the data sets for 18 of the tested compounds, and the concentration at which a concerted molecular response occurred (transcriptomic point of departure; tPOD) was calculated. The tPODs, based on measured concentrations of PFAS, generally ranged from 0.03 to 0.58 µM (9.9-350 µg/L; interquartile range). In most cases, these concentrations were two orders of magnitude lower than similarly calculated tPODs for human cell lines exposed to PFAS. They were also lower than apical effect concentrations reported for seven PFAS for which some crustacean or invertebrate toxicity data were available, although there were a few exceptions. Despite being lower than most other available hazard benchmarks, D. magna tPODs were, on average, four orders of magnitude greater than the maximum aqueous concentrations of PFAS measured in Great Lakes tributaries. Overall, this high-throughput transcriptomics assay with D. magna holds promise as a component of a tiered hazard evaluation strategy employing new approach methodologies. Environ Toxicol Chem 2024;00:1-16. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Daniel L Villeneuve
- Great Lakes Toxicology and Ecology Division, US Environmental Protection Agency, Duluth, MN, USA
| | - Brett R Blackwell
- Great Lakes Toxicology and Ecology Division, US Environmental Protection Agency, Duluth, MN, USA
- Bioscience Division, Biochemistry and Biotechnology Group, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Kendra Bush
- Oak Ridge Institute for Science and Education Research Participant at US EPA, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Joshua Harrill
- Biomolecular and Computational Toxicology Division, United States Environmental Protection Agency, NC, USA
| | - Felix Harris
- Oak Ridge Institute for Science and Education Research Participant at US EPA, Biomolecular and Computational Toxicology Division, Oak Ridge, NC, USA
| | - Monique Hazemi
- Oak Ridge Institute for Science and Education Research Participant at US EPA, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Michelle Le
- Oak Ridge Institute for Science and Education Research Participant at US EPA, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Emma Stacy
- Great Lakes Toxicology and Ecology Division, US Environmental Protection Agency, Duluth, MN, USA
| | - Kevin M Flynn
- Great Lakes Toxicology and Ecology Division, US Environmental Protection Agency, Duluth, MN, USA
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Ford LC, Lin HC, Tsai HHD, Zhou YH, Wright FA, Sedykh A, Shah RR, Chiu WA, Rusyn I. Hazard and risk characterization of 56 structurally diverse PFAS using a targeted battery of broad coverage assays using six human cell types. Toxicology 2024; 503:153763. [PMID: 38423244 PMCID: PMC11214689 DOI: 10.1016/j.tox.2024.153763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/13/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
Per- and poly-fluoroalkyl substances (PFAS) are extensively used in commerce leading to their prevalence in the environment. Due to their chemical stability, PFAS are considered to be persistent and bioaccumulative; they are frequently detected in both the environment and humans. Because of this, PFAS as a class (composed of hundreds to thousands of chemicals) are contaminants of very high concern. Little information is available for the vast majority of PFAS, and regulatory agencies lack safety data to determine whether exposure limits or restrictions are needed. Cell-based assays are a pragmatic approach to inform decision-makers on potential health hazards; therefore, we hypothesized that a targeted battery of human in vitro assays can be used to determine whether there are structure-bioactivity relationships for PFAS, and to characterize potential risks by comparing bioactivity (points of departure) to exposure estimates. We tested 56 PFAS from 8 structure-based subclasses in concentration response (0.1-100 μM) using six human cell types selected from target organs with suggested adverse effects of PFAS - human induced pluripotent stem cell (iPSC)-derived hepatocytes, neurons, and cardiomyocytes, primary human hepatocytes, endothelial and HepG2 cells. While many compounds were without effect; certain PFAS demonstrated cell-specific activity highlighting the necessity of using a compendium of in vitro models to identify potential hazards. No class-specific groupings were evident except for some chain length- and structure-related trends. In addition, margins of exposure (MOE) were derived using empirical and predicted exposure data. Conservative MOE calculations showed that most tested PFAS had a MOE in the 1-100 range; ∼20% of PFAS had MOE<1, providing tiered priorities for further studies. Overall, we show that a compendium of human cell-based models can be used to derive bioactivity estimates for a range of PFAS, enabling comparisons with human biomonitoring data. Furthermore, we emphasize that establishing structure-bioactivity relationships may be challenging for the tested PFAS.
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Affiliation(s)
- Lucie C Ford
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Hsing-Chieh Lin
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Han-Hsuan D Tsai
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Yi-Hui Zhou
- Department of Biological Sciences and Statistics, North Carolina State University, Raleigh, NC 27695, USA; Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695, USA
| | - Fred A Wright
- Department of Biological Sciences and Statistics, North Carolina State University, Raleigh, NC 27695, USA; Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695, USA
| | | | | | - Weihsueh A Chiu
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA
| | - Ivan Rusyn
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX 77843, USA.
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7
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Tsai HHD, Ford LC, Chen Z, Dickey AN, Wright FA, Rusyn I. Risk-based prioritization of PFAS using phenotypic and transcriptomic data from human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes. ALTEX 2024; 41:363-381. [PMID: 38429992 PMCID: PMC11305846 DOI: 10.14573/altex.2311031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/20/2024] [Indexed: 03/03/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are chemicals with important applications; they are persistent in the environment and may pose human health hazards. Regulatory agencies are considering restrictions and bans of PFAS; however, little data exists for informed decisions. Several prioritization strategies were proposed for evaluation of potential hazards of PFAS. Structure-based grouping could expedite the selection of PFAS for testing; still, the hypothesis that structure-effect relationships exist for PFAS requires confirmation. We tested 26 structurally diverse PFAS from 8 groups using human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes, and tested concentration-response effects on cell function and gene expression. Few phenotypic effects were observed in hepatocytes, but negative chronotropy was observed in cardiomyocytes for 8 PFAS. Substance- and cell type-dependent transcriptomic changes were more prominent but lacked substantial group-specific effects. In hepatocytes, we found upregulation of stress-related and extracellular matrix organization pathways, and down-regulation of fat metabolism. In cardiomyocytes, contractility-related pathways were most affected. We derived phenotypic and transcriptomic points of departure and compared them to predicted PFAS exposures. Conservative estimates for bioactivity and exposure were used to derive a bioactivity-to-exposure ratio (BER) for each PFAS; 23 of 26 PFAS had BER > 1. Overall, these data suggest that structure-based PFAS grouping may not be sufficient to predict their biological effects. Testing of individual PFAS may be needed for scientifically-supported decision-making. Our proposed strategy of using two human cell types and considering phenotypic and transcriptomic effects, combined with dose-response analysis and calculation of BER, may be used for PFAS prioritization.
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Affiliation(s)
- Han-Hsuan D Tsai
- Interdisciplinary Faculty of Toxicology, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Lucie C Ford
- Interdisciplinary Faculty of Toxicology, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
| | - Zunwei Chen
- Interdisciplinary Faculty of Toxicology, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
- Current address: Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Allison N Dickey
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | - Fred A Wright
- Interdisciplinary Faculty of Toxicology, College Station, TX, USA
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
- Department of Statistics and Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | - Ivan Rusyn
- Interdisciplinary Faculty of Toxicology, College Station, TX, USA
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, TX, USA
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8
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Fischer FC, Ludtke S, Thackray C, Pickard HM, Haque F, Dassuncao C, Endo S, Schaider L, Sunderland EM. Binding of Per- and Polyfluoroalkyl Substances (PFAS) to Serum Proteins: Implications for Toxicokinetics in Humans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1055-1063. [PMID: 38166384 PMCID: PMC11149785 DOI: 10.1021/acs.est.3c07415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a diverse class of highly persistent anthropogenic chemicals that are detectable in the serum of most humans. PFAS exposure has been associated with many adverse effects on human health including immunotoxicity, increased risk of certain cancers, and metabolic disruption. PFAS binding to the most abundant blood serum proteins (human serum albumin [HSA] and globulins) is thought to affect transport to active sites, toxicity, and elimination half-lives. However, few studies have investigated the competitive binding of PFAS to these proteins in human serum. Here, we use C18 solid-phase microextraction fibers to measure HSA-water and globulin-water distribution coefficients (DHSA/w, Dglob/w) for PFAS with carbon chains containing 4 to 13 perfluorinated carbons (ηpfc = 4-13) and several functional head-groups. PFAS with ηpfc < 7 were highly bound to HSA relative to globulins, whereas PFAS with ηpfc ≥ 7 showed a greater propensity for binding to globulins. Experimentally measured DHSA/w and Dglob/w and concentrations of serum proteins successfully predicted the variability in PFAS binding in human serum. We estimated that the unbound fraction of serum PFAS varied by up to a factor of 2.5 among individuals participating in the 2017-2018 U.S. National Health and Nutrition Examination Survey. These results suggest that serum HSA and globulins are important covariates for epidemiological studies aimed at understanding the effects of PFAS exposure.
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Affiliation(s)
- Fabian Christoph Fischer
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Sophia Ludtke
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Colin Thackray
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Heidi M Pickard
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Faiz Haque
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Clifton Dassuncao
- Eastern Research Group, Inc. (ERG), Arlington, Virginia 22201, United States
| | - Satoshi Endo
- National Institute for Environmental Studies (NIES), Health and Environmental Risk Division, Onogawa 16-2, Tsukuba, Ibaraki 305-8506, Japan
| | - Laurel Schaider
- Silent Spring Institute, Newton, Massachusetts 02460, United States
| | - Elsie M Sunderland
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, United States
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, Massachusetts 02138, United States
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9
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Wu Y, Bao J, Liu Y, Wang X, Lu X, Wang K. In Vitro and In Silico Analysis of the Bindings between Legacy and Novel Per- and Polyfluoroalkyl Substances and Human Serum Albumin. TOXICS 2024; 12:46. [PMID: 38251003 PMCID: PMC10818824 DOI: 10.3390/toxics12010046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/29/2023] [Accepted: 01/05/2024] [Indexed: 01/23/2024]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are emerging contaminants of concern that can enter the human body through a variety of pathways and thereby cause harmful effects. Exposure of pregnant women to PFASs could even affect both the mother and the child. Human serum albumin (HSA) is considered to be the primary transport protein for a variety of substances in body fluids. It can be bound to different contaminants and might result in possible effects on human health. Yet, few studies are available on the binding affinity of legacy PFASs and their novel alternatives to HSA. In this study, the binding mechanisms of HSA to both legacy PFASs and their novel alternatives were investigated using fluorescence spectroscopy, together with further molecular docking. The results show that all the target PFASs were statically quenched against HSA with binding ratios of 1:1. The binding constants of long-chain PFASs and novel alternatives of perfluoroalkanesulfonic acids (PFSAs) were greater than 102, whereas those of short-chain PFASs alternatives and novel alternatives of perfluorocarboxylic acids (PFCAs) were less than 102. In general, the binding affinities of PFCAs on HSA were less than that of PFSAs, while the binding affinities of short-chain PFASs alternatives on HSA were smaller than those of long-chain PFASs and their novel alternatives. Therefore, bindings to HSA could be considered as an important influencing factor for the bioaccumulation of legacy and novel PFASs in the human body.
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Affiliation(s)
- Yuqing Wu
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Jia Bao
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Yang Liu
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Xin Wang
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Xinyi Lu
- School of Environmental and Chemical Engineering, Shenyang University of Technology, Shenyang 110870, China
| | - Ke Wang
- Department of Clinical Nutrition, Second Affiliated Hospital of Dalian Medical University, Dalian 116023, China
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10
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Peng M, Xu Y, Wu Y, Cai X, Zhang W, Zheng L, Du E, Fu J. Binding Affinity and Mechanism of Six PFAS with Human Serum Albumin: Insights from Multi-Spectroscopy, DFT and Molecular Dynamics Approaches. TOXICS 2024; 12:43. [PMID: 38250999 PMCID: PMC10819430 DOI: 10.3390/toxics12010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/30/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024]
Abstract
Per- and Polyfluoroalkyl Substances (PFAS) bioaccumulate in the human body, presenting potential health risks and cellular toxicity. Their transport mechanisms and interactions with tissues and the circulatory system require further investigation. This study investigates the interaction mechanisms of six PFAS with Human Serum Albumin (HSA) using multi-spectroscopy, DFT and a molecular dynamics approach. Multi-spectral analysis shows that perfluorononanoic acid (PFNA) has the best binding capabilities with HSA. The order of binding constants (298 K) is as follows: "Perfluorononanoic Acid (PFNA, 7.81 × 106 L·mol-1) > Perfluoro-2,5-dimethyl-3,6-dioxanonanoic Acid (HFPO-TA, 3.70 × 106 L·mol-1) > Perfluorooctanoic Acid (PFOA, 2.27 × 105 L·mol-1) > Perfluoro-3,6,9-trioxadecanoic Acid (PFO3DA, 1.59 × 105 L·mol-1) > Perfluoroheptanoic Acid (PFHpA, 4.53 × 103 L·mol-1) > Dodecafluorosuberic Acid (DFSA, 1.52 × 103 L·mol-1)". Thermodynamic analysis suggests that PFNA and PFO3DA's interactions with HSA are exothermic, driven primarily by hydrogen bonds or van der Waals interactions. PFHpA, DFSA, PFOA, and HFPO-TA's interactions with HSA, on the other hand, are endothermic processes primarily driven by hydrophobic interactions. Competitive probe results show that the main HSA-PFAS binding site is in the HSA structure's subdomain IIA. These findings are also consistent with the findings of molecular docking. Molecular dynamics simulation (MD) analysis further shows that the lowest binding energy (-38.83 kcal/mol) is fund in the HSA-PFNA complex, indicating that PFNA binds more readily with HSA. Energy decomposition analysis also indicates that van der Waals and electrostatic interactions are the main forces for the HSA-PFAS complexes. Correlation analysis reveals that DFT quantum chemical descriptors related to electrostatic distribution and characteristics like ESP and ALIE are more representative in characterizing HSA-PFAS binding. This study sheds light on the interactions between HSA and PFAS. It guides health risk assessments and control strategies against PFAS, serving as a critical starting point for further public health research.
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Affiliation(s)
- Mingguo Peng
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Yang Xu
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Yao Wu
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Xuewen Cai
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Weihua Zhang
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Lu Zheng
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Erdeng Du
- School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China; (Y.X.); (Y.W.); (X.C.); (W.Z.); (L.Z.)
| | - Jiajun Fu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
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11
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Renyer A, Ravindra K, Wetmore BA, Ford JL, DeVito M, Hughes MF, Wehmas LC, MacMillan DK. Dose Response, Dosimetric, and Metabolic Evaluations of Replacement PFAS Perfluoro-(2,5,8-trimethyl-3,6,9-trioxadodecanoic) Acid (HFPO-TeA). TOXICS 2023; 11:951. [PMID: 38133352 PMCID: PMC10747602 DOI: 10.3390/toxics11120951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/20/2023] [Accepted: 11/18/2023] [Indexed: 12/23/2023]
Abstract
Few studies are available on the environmental and toxicological effects of perfluoroalkyl ether carboxylic acids (PFECAs), such as GenX, which are replacing legacy PFAS in manufacturing processes. To collect initial data on the toxicity and toxicokinetics of a longer-chain PFECA, male and female Sprague Dawley rats were exposed to perfluoro-(2,5,8-trimethyl-3,6,9-trioxadodecanoic) acid (HFPO-TeA) by oral gavage for five days over multiple dose levels (0.3-335.2 mg/kg/day). Clinically, we observed mortality at doses >17 mg/kg/day and body weight changes at doses ≤17 mg/kg/day. For the 17 mg/kg/day dose level, T3 and T4 thyroid hormone concentrations were significantly decreased (p < 0.05) from controls and HFPO-TeA plasma concentrations were significantly different between sexes. Non-targeted analysis of plasma and in vitro hepatocyte assay extractions revealed the presence of another GenX oligomer, perfluoro-(2,5-dimethyl-3,6-dioxanonanoic) acid (HFPO-TA). In vitro to in vivo extrapolation (IVIVE) parameterized with in vitro toxicokinetic data predicted steady-state blood concentrations that were within seven-fold of those observed in the in vivo study, demonstrating reasonable predictivity. The evidence of thyroid hormone dysregulation, sex-based differences in clinical results and dosimetry, and IVIVE predictions presented here suggest that the replacement PFECA HFPO-TeA induces a complex and toxic exposure response in rodents.
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Affiliation(s)
- Aero Renyer
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37830, USA;
| | - Krishna Ravindra
- Oak Ridge Associated Universities (ORAU), Oak Ridge, TN 37830, USA;
| | - Barbara A. Wetmore
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
| | - Jermaine L. Ford
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
| | - Michael DeVito
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
| | - Michael F. Hughes
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
| | - Leah C. Wehmas
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
| | - Denise K. MacMillan
- Center for Computational Toxicology and Exposure, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Durham, NC 27709, USA; (B.A.W.); (J.L.F.); (M.D.); (M.F.H.); (L.C.W.)
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12
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de Schepper JKH, van Oorschot Y, Jaspers RJ, Hamers T, Lamoree MH, Behnisch P, Besselink H, Houtman CJ. The contribution of PFAS to thyroid hormone-displacing activity in Dutch waters: A comparison between two in vitro bioassays with chemical analysis. ENVIRONMENT INTERNATIONAL 2023; 181:108256. [PMID: 37862862 DOI: 10.1016/j.envint.2023.108256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/12/2023] [Accepted: 10/09/2023] [Indexed: 10/22/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a group of xenobiotics that are widely distributed throughout the aquatic environment. Many PFAS are possible thyroid hormone (TH) system disrupting compounds, because they have the capacity to -amongst other- inhibit the TH thyroxine (T4) from binding to its transport protein transthyretin (TTR). This study investigated the occurrence of TH-displacing activity in the Dutch water cycle, and more specifically, the contribution of PFAS to this effect. Over one year of monitoring data of 29 PFAS (linear and branched) showed the continuous presence of PFAS in drinking waters and their surface water sources. Secondly, the FITC-T4 and TTR-TRβ-CALUX bioassays were mutually compared using positive (HPLC-grade water spiked with PFOA) and negative control samples (HPLC-grade water), as well as relative potency factors (RPFs) of up to 20 PFAS congeners. Both assays were found to be suitable for measuring TH-displacing activity in water samples. As a third aim, a field study was performed in the Dutch water cycle that was comprised of samples from drinking water, surface water, PFAS contaminated sites, and 2 wastewater treatment plants. All samples were analyzed with 1. chemical analysis for 29 PFAS, 2. the FITC-T4 bioassay, and 3. the TTR-TRβ-CALUX bioassay. The bioassays mutually showed good correlation (R2 0.85). Bioanalytical equivalent concentrations (BEQ) based on chemically-determined concentrations and RPFs (BEQchem) revealed that analyzed PFAS only explained ≤4.1 % of their activity in water extracts measured by both bioassays (BEQbio). This indicated that as yet unknown compounds contribute to the majority of the measured TH-displacing activity. Moreover, water treatment processes (e.g. DW production from SW) showed a larger contribution of target PFAS to the BEQbio. This could be a first lead to identify unknown compounds that contribute to this activity, and as such, enable the assessment of possible risks associated by the occurrence of TH-displacing activity in water.
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Affiliation(s)
- J K H de Schepper
- The Water Laboratory, 2031 BE Haarlem, the Netherlands; Amsterdam Institute for Life and Environment (A-LIFE), Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands.
| | | | - R J Jaspers
- The Water Laboratory, 2031 BE Haarlem, the Netherlands
| | - T Hamers
- Amsterdam Institute for Life and Environment (A-LIFE), Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - M H Lamoree
- Amsterdam Institute for Life and Environment (A-LIFE), Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - P Behnisch
- BioDetection Systems B.V. (BDS), 1098 XH Amsterdam, the Netherlands
| | - H Besselink
- BioDetection Systems B.V. (BDS), 1098 XH Amsterdam, the Netherlands
| | - C J Houtman
- The Water Laboratory, 2031 BE Haarlem, the Netherlands; Amsterdam Institute for Life and Environment (A-LIFE), Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
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13
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Kreutz A, Clifton MS, Henderson WM, Smeltz MG, Phillips M, Wambaugh JF, Wetmore BA. Category-Based Toxicokinetic Evaluations of Data-Poor Per- and Polyfluoroalkyl Substances (PFAS) using Gas Chromatography Coupled with Mass Spectrometry. TOXICS 2023; 11:toxics11050463. [PMID: 37235277 DOI: 10.3390/toxics11050463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/28/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023]
Abstract
Concern over per- and polyfluoroalkyl substances (PFAS) has increased as more is learned about their environmental presence, persistence, and bioaccumulative potential. The limited monitoring, toxicokinetic (TK), and toxicologic data available are inadequate to inform risk across this diverse domain. Here, 73 PFAS were selected for in vitro TK evaluation to expand knowledge across lesser-studied PFAS alcohols, amides, and acrylates. Targeted methods developed using gas chromatography-tandem mass spectrometry (GC-MS/MS) were used to measure human plasma protein binding and hepatocyte clearance. Forty-three PFAS were successfully evaluated in plasma, with fraction unbound (fup) values ranging from 0.004 to 1. With a median fup of 0.09 (i.e., 91% bound), these PFAS are highly bound but exhibit 10-fold lower binding than legacy perfluoroalkyl acids recently evaluated. Thirty PFAS evaluated in the hepatocyte clearance assay showed abiotic loss, with many exceeding 60% loss within 60 min. Metabolic clearance was noted for 11 of the 13 that were successfully evaluated, with rates up to 49.9 μL/(min × million cells). The chemical transformation simulator revealed potential (bio)transformation products to consider. This effort provides critical information to evaluate PFAS for which volatility, metabolism, and other routes of transformation are likely to modulate their environmental fates.
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Affiliation(s)
- Anna Kreutz
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Road, Oak Ridge, TN 37830, USA
| | - Matthew S Clifton
- US Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Research Triangle Park, NC 27711, USA
| | - W Matthew Henderson
- US Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Athens, GA 30605, USA
| | - Marci G Smeltz
- US Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Research Triangle Park, NC 27711, USA
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC 27711, USA
| | - Matthew Phillips
- Oak Ridge Associated Universities, 100 ORAU Way, Oak Ridge, TN 37830, USA
| | - John F Wambaugh
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC 27711, USA
| | - Barbara A Wetmore
- US Environmental Protection Agency, Office of Research and Development, Center for Computational Toxicology and Exposure, Research Triangle Park, NC 27711, USA
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