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Korzeniowski SH, Buck RC, Newkold RM, Kassmi AE, Laganis E, Matsuoka Y, Dinelli B, Beauchet S, Adamsky F, Weilandt K, Soni VK, Kapoor D, Gunasekar P, Malvasi M, Brinati G, Musio S. A critical review of the application of polymer of low concern regulatory criteria to fluoropolymers II: Fluoroplastics and fluoroelastomers. Integr Environ Assess Manag 2023; 19:326-354. [PMID: 35678199 DOI: 10.1002/ieam.4646] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/07/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Fluoropolymers are a distinct class of per- and polyfluoroalkyl substances (PFAS), high molecular weight (MW) polymers with fluorine attached to their carbon-only backbone. Fluoropolymers possess a unique combination of properties and unmatched functional performance critical to the products and manufacturing processes they enable and are irreplaceable in many uses. Fluoropolymers have documented safety profiles; are thermally, biologically, and chemically stable, negligibly soluble in water, nonmobile, nonbioavailable, nonbioaccumulative, and nontoxic. Although fluoropolymers fit the PFAS structural definition, they have very different physical, chemical, environmental, and toxicological properties when compared with other PFAS. This study describes the composition, uses, performance properties, and functionalities of 14 fluoropolymers, including fluoroplastics and fluoroelastomers, and presents data to demonstrate that they satisfy the widely accepted polymer hazard assessment criteria to be considered polymers of low concern (PLC). The PLC criteria include physicochemical properties, such as molecular weight, which determine bioavailability and warn of potential hazard. Fluoropolymers are insoluble (e.g., water, octanol) solids too large to migrate into the cell membrane making them nonbioavailable, and therefore, of low concern from a human and environmental health standpoint. Further, the study results demonstrate that fluoropolymers are a distinct and different group of PFAS and should not be grouped with other PFAS for hazard assessment or regulatory purposes. When combined with an earlier publication by Henry et al., this study demonstrates that commercial fluoropolymers are available from the seven participating companies that meet the criteria to be considered PLC, which represent approximately 96% of the global commercial fluoropolymer market. Integr Environ Assess Manag 2023;19:326-354. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
| | | | | | | | - Evan Laganis
- AGC Chemicals Americas, Exton, Pennsylvania, USA
| | | | | | | | | | - Karl Weilandt
- Advanced Materials Division, 3M Center, 3M Company, St. Paul, Minnesota, USA
| | | | - Deepak Kapoor
- Gujarat Fluorochemicals GmbH, Regus Centre Watermark, Hamburg, Germany
| | | | - Marco Malvasi
- Solvay Specialty Polymers, V.le Lombardia, Bollate, (MI), Italy
| | - Giulio Brinati
- Solvay Specialty Polymers, V.le Lombardia, Bollate, (MI), Italy
| | - Stefana Musio
- Solvay Specialty Polymers, V.le Lombardia, Bollate, (MI), Italy
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Buck RC, Korzeniowski SH, Laganis E, Adamsky F. Identification and classification of commercially relevant per- and poly-fluoroalkyl substances (PFAS). Integr Environ Assess Manag 2021; 17:1045-1055. [PMID: 33991049 PMCID: PMC9292543 DOI: 10.1002/ieam.4450] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/11/2021] [Accepted: 05/06/2021] [Indexed: 05/04/2023]
Abstract
Per- and poly-fluoroalkyl substances (PFAS) are a universe of fluorinated organic substances with very different physical, chemical, and biological properties including polymers and non-polymers; solids, liquids, and gases. Commercial PFAS-based products have been used in a wide variety of industrial and consumer applications because they have unique performance properties of significant socioeconomic value. The PFAS definition has evolved and expanded over the years. Numerous lists of PFAS, some with thousands of entries, have been compiled, but none have clearly identified which of the substances are commercially relevant. This study is the first to use a bona-fide "bottom up" approach to identify how many of the 4730 PFAS substances listed in a 2018 OECD/UNEP Report are directly connected to commercial products based on input from three major global producers. This study provides new and valuable insight into the 2018 OECD/UNEP Report list of PFAS substances. The results show that 256, less than 6%, of the 4730 PFAS substances presented in the 2018 OECD/UNEP Report are commercially relevant globally. This study suggests that grouping and categorizing PFAS using fundamental classification criteria based on composition and structure can be used to identify appropriate groups of PFAS substances for risk assessment, thereby dispelling assertions that there are too many PFAS chemistries to conduct proper regulatory risk assessments for the commercially relevant substances. Integr Environ Assess Manag 2021;17:1045-1055. © 2021 The Chemours Company, Beach Edge Consulting, LLC, AGC Chemicals Americas Inc., Daikin America Inc. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Johnson MS, Buck RC, Cousins IT, Weis CP, Fenton SE. Estimating Environmental Hazard and Risks from Exposure to Per- and Polyfluoroalkyl Substances (PFASs): Outcome of a SETAC Focused Topic Meeting. Environ Toxicol Chem 2021; 40:543-549. [PMID: 32452041 PMCID: PMC8387100 DOI: 10.1002/etc.4784] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/27/2020] [Accepted: 05/20/2020] [Indexed: 05/08/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a group of highly fluorinated synthetic chemicals that were originally developed for uses as surfactants and surface protectors. Increasingly, specific substances of this class are being found in environmental media (e.g., surface water, soils, sediments, food sources), and concerns regarding exposure to humans and environmental receptors have been described by the public, legislators, and the general population. Data suggest that some PFAS (such as certain of the long-chain ones) bioaccumulate and have long biological half-lives, particularly in humans. Toxicity data in various organisms are variable as are their toxicokinetics. A Society of Environmental Toxicology and Chemistry (SETAC) Focused Topic Meeting and workshop entitled Environmental Risk Assessment of PFAS convened during 12 to 15 August, 2019 in Durham, North Carolina (USA) and brought together experts from around the globe to highlight recent advances in research pertinent to evaluating environmental and human health risks from exposures. The objectives of the Focused Topic Meeting and workshop were: 1) to review new and emerging information on PFAS chemical classification and grouping, environmental chemistry, detection technology, fate and transport, exposure potential, human health toxicity, and ecological toxicity; and 2) to harness the expertise of attendees to discuss and formulate a roadmap to prioritize the study of specific PFAS with the goal of developing a risk assessment approach that considers mechanistic (including computational) data for extrapolating exposure and data across different species/scenarios and compounds within environmental exposure pathways. We present the key issues that were discussed. Environ Toxicol Chem 2021;40:543-549. © 2020 SETAC.
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Affiliation(s)
- Mark S Johnson
- Army Public Health Center, Aberdeen Proving Ground, Maryland, USA
| | | | - Ian T Cousins
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Christopher P Weis
- National Institutes of Health/National Institute of Environmental Health Sciences, Bethesda, Maryland, USA
| | - Suzanne E Fenton
- Division of the National Toxicology Program/National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Henry BJ, Carlin JP, Hammerschmidt JA, Buck RC, Buxton LW, Fiedler H, Seed J, Hernandez O. A critical review of the application of polymer of low concern and regulatory criteria to fluoropolymers. Integr Environ Assess Manag 2018; 14:316-334. [PMID: 29424474 DOI: 10.1002/ieam.4035] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/16/2018] [Accepted: 01/30/2018] [Indexed: 05/20/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a group of fluorinated substances that are in the focus of researchers and regulators due to widespread presence in the environment and biota, including humans, of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). Fluoropolymers, high molecular weight polymers, have unique properties that constitute a distinct class within the PFAS group. Fluoropolymers have thermal, chemical, photochemical, hydrolytic, oxidative, and biological stability. They have negligible residual monomer and oligomer content and low to no leachables. Fluoropolymers are practically insoluble in water and not subject to long-range transport. With a molecular weight well over 100 000 Da, fluoropolymers cannot cross the cell membrane. Fluoropolymers are not bioavailable or bioaccumulative, as evidenced by toxicology studies on polytetrafluoroethylene (PTFE): acute and subchronic systemic toxicity, irritation, sensitization, local toxicity on implantation, cytotoxicity, in vitro and in vivo genotoxicity, hemolysis, complement activation, and thrombogenicity. Clinical studies of patients receiving permanently implanted PTFE cardiovascular medical devices demonstrate no chronic toxicity or carcinogenicity and no reproductive, developmental, or endocrine toxicity. This paper brings together fluoropolymer toxicity data, human clinical data, and physical, chemical, thermal, and biological data for review and assessment to show that fluoropolymers satisfy widely accepted assessment criteria to be considered as "polymers of low concern" (PLC). This review concludes that fluoropolymers are distinctly different from other polymeric and nonpolymeric PFAS and should be separated from them for hazard assessment or regulatory purposes. Grouping fluoropolymers with all classes of PFAS for "read across" or structure-activity relationship assessment is not scientifically appropriate. Integr Environ Assess Manag 2018;14:316-334. © 2018 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
| | | | | | | | | | - Heidelore Fiedler
- MTM Research Centre School of Science and Technology, Örebro University, Örebro, Sweden
| | - Jennifer Seed
- Risk Assessment Consultant, Alexandria, Virginia, USA
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Zhang S, Lu X, Wang N, Buck RC. Biotransformation potential of 6:2 fluorotelomer sulfonate (6:2 FTSA) in aerobic and anaerobic sediment. Chemosphere 2016; 154:224-230. [PMID: 27058914 DOI: 10.1016/j.chemosphere.2016.03.062] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/10/2016] [Accepted: 03/13/2016] [Indexed: 05/03/2023]
Abstract
Aqueous film-forming foam (AFFF) products are used in industrial and military firefighting around the globe. These products contain fluoroalkylthioamido sulfonates, fluoroalkylthiobetaine, and other related substances as the major ingredients, which can be biotransformed in the environment to form 6:2 fluorotelomer sulfonate (6:2 FTSA, F(CF2)6CH2CH2SO3-) as one of the major initial biotransformation products. Limited information is available on 6:2 FTSA aerobic biotransformation in activated sludge and pure microbial culture. This is the first study to report 6:2 FTSA biotransformation in aerobic and anaerobic sediment. 6:2 FTSA was rapidly biotransformed in aerobic river sediment with a half-life less than 5 d. Major stable transformation products observed after 90 d included 5:3 Acid [F(CF2)5CH2CH2COOH), 16 mol%), PFPeA [F(CF2)4COOH, 21 mol%] and PFHxA (F(CF2)5COOH, 20 mol%). 6:2 fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] was readily biotransfomed whereas 6:2 FTSA biotransformation did not occur in anaerobic sediment over 100 d, indicating that the enzymatic desulfonation step limited 6:2 FTSA biotransformation in anaerobic sediment. These results suggest that 6:2 FTSA related products, after release to the aerobic environment, is likely to biodegrade forming 5:3 Acid, PFPeA and PFHxA. This study also indicates that 6:2 FTSA formed from its aforementioned precursors may be persistent in the anaerobic environment after their potential release. This work provides insight to understanding the fate and environmental loading of AFFF-related products and their major transformation products in the environment.
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Affiliation(s)
- Shu Zhang
- Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Xiaoxia Lu
- Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
| | - Ning Wang
- E.I. du Pont de Nemours & Company, Inc., Wilmington, DE, USA.
| | - Robert C Buck
- The Chemours Company, 1007 Market Street, P.O. Box 2047, Wilmington, DE, 19899, USA
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Hoke RA, Ferrell BD, Sloman TL, Buck RC, Buxton LW. Aquatic hazard, bioaccumulation and screening risk assessment for ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate. Chemosphere 2016; 149:336-42. [PMID: 26874062 DOI: 10.1016/j.chemosphere.2016.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 12/18/2015] [Accepted: 01/04/2016] [Indexed: 05/26/2023]
Abstract
The fluoropolymer manufacturing industry is moving to alternative polymerization processing aid technologies with more favorable toxicological and environmental profiles as part of a commitment to curtail the use of long-chain perfluoroalkyl acids (PFAAs). To facilitate the environmental product stewardship assessment and premanufacture notification (PMN) process for a candidate replacement chemical, we conducted acute and chronic aquatic toxicity tests to evaluate the toxicity of ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate (C6HF11O3.H3N) or the acid form of the substance to the cladoceran, Daphnia magna, the green alga, Pseudokirchneriella subcapitata, and a number of freshwater fish species including the rainbow trout, Oncorhynchus mykiss, In addition, testing with the common carp, Cyprinus carpio, was conducted to determine the bioconcentration potential of the acid form of the compound. Based on the relevant criteria in current regulatory frameworks, the results of the aquatic toxicity and bioconcentration studies indicate the substance is of low concern for aquatic hazard and bioconcentration in aquatic organisms. Evaluation of environmental monitoring data in conjunction with the predicted no effect concentration (PNEC) based on the available data suggest low risk to aquatic organisms.
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Affiliation(s)
- Robert A Hoke
- E. I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, U.S.A.
| | - Barbra D Ferrell
- E. I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, U.S.A
| | - Terry L Sloman
- E. I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, U.S.A
| | - Robert C Buck
- The Chemours Company, 1007 Market Street, Wilmington, DE 19801, U.S.A
| | - L William Buxton
- The Chemours Company, 1007 Market Street, Wilmington, DE 19801, U.S.A
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Gannon SA, Fasano WJ, Mawn MP, Nabb DL, Buck RC, Buxton LW, Jepson GW, Frame SR. Absorption, distribution, metabolism, excretion, and kinetics of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid ammonium salt following a single dose in rat, mouse, and cynomolgus monkey. Toxicology 2015; 340:1-9. [PMID: 26743852 DOI: 10.1016/j.tox.2015.12.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/14/2015] [Accepted: 12/23/2015] [Indexed: 10/22/2022]
Abstract
Ammonium, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate has been developed as a processing aid used in the manufacture of fluoropolymers. The absorption, distribution, elimination, and distribution (ADME) and kinetic behavior of this substance has been evaluated in rats, mice, and cynomolgus monkeys by oral and intravenous routes of exposure and studied in both plasma and urine. The test substance is rapidly and completely absorbed in both rats and mice and both in vivo and in vitro experiments indicate that it is not metabolized. The test substance is rapidly eliminated exclusively in the urine in both rats and mice, with rats eliminating it more quickly than mice (approximately 5h elimination half-life in rats, 20 h half-life in mice). Pharmacokinetic analysis in monkeys, rats, and mice indicate rapid, biphasic elimination characterized by a very fast alpha phase and a slower beta phase. The beta phase does not contribute to potential accumulation after multiple dosing in rats or monkeys. Comparative pharmacokinetics in rats, mice, and monkeys indicates that the rat is more similar to the monkey and is therefore a more appropriate rodent model for pharmacokinetics in primates.
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Affiliation(s)
| | - William J Fasano
- E I. duPont de Nemours and Company, Haskell Global Centers for Health & Environmental Sciences, Newark, DE 19714, USA
| | | | - Diane L Nabb
- E I. duPont de Nemours and Company, Haskell Global Centers for Health & Environmental Sciences, Newark, DE 19714, USA
| | | | | | | | - Steven R Frame
- E I. duPont de Nemours and Company, Haskell Global Centers for Health & Environmental Sciences, Newark, DE 19714, USA
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Hoke RA, Ferrell BD, Ryan T, Sloman TL, Green JW, Nabb DL, Mingoia R, Buck RC, Korzeniowski SH. Aquatic hazard, bioaccumulation and screening risk assessment for 6:2 fluorotelomer sulfonate. Chemosphere 2015; 128:258-265. [PMID: 25725394 DOI: 10.1016/j.chemosphere.2015.01.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/06/2015] [Accepted: 01/08/2015] [Indexed: 06/04/2023]
Abstract
This study assessed the aquatic toxicity and bioaccumulation potential of 6:2 fluorotelomer sulfonate (6:2 FTSA). Acute and chronic aquatic hazard endpoints indicate 6:2 FTSA is not classified for aquatic hazard according to GHS or European CLP legislation. The aqueous bioconcentration factors for 6:2 FTSA were <40 and the dietary assimilation efficiency, growth corrected half-life and dietary biomagnification factor (BMF) were 0.435, 23.1d and 0.295, respectively. These data indicate that 6:2 FTSA is not bioaccumulative in aquatic organisms. Comparison of PNECs with the reported surface water concentrations (non-spill situations) suggests low risk to aquatic organisms from 6:2 FTSA. Future studies are needed to elucidate the biotic and abiotic fate of commercial AFFF surfactants in the environment.
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Affiliation(s)
- Robert A Hoke
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA.
| | - Barbra D Ferrell
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Tim Ryan
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Terry L Sloman
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - John W Green
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Diane L Nabb
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Robert Mingoia
- E.I. du Pont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19711, USA
| | - Robert C Buck
- E.I. du Pont de Nemours and Company, Inc., Chemicals & Fluoroproducts, Wilmington, DE 19805, USA
| | - Stephen H Korzeniowski
- E.I. du Pont de Nemours and Company, Inc., Chemicals & Fluoroproducts, Wilmington, DE 19805, USA
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Russell MH, Himmelstein MW, Buck RC. Inhalation and oral toxicokinetics of 6:2 FTOH and its metabolites in mammals. Chemosphere 2015; 120:328-35. [PMID: 25180935 DOI: 10.1016/j.chemosphere.2014.07.092] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 05/21/2023]
Abstract
The toxicokinetics of 6:2 fluorotelomer alcohol (6:2 FTOH) and its terminal perfluorinated and polyfluorinated metabolites (PFBA, PFHxA, PFHpA and 5:3 Acid) have been calculated from laboratory studies of rats and from a biomonitoring study of humans. In vitro studies with mouse, rat and human hepatocytes indicate qualitatively similar metabolic pathways of 6:2 FTOH. In a one-day inhalation study of 6:2 FTOH in rats, PFBA, PFHxA, PFHpA and 5:3 Acid were determined to be the major metabolites in plasma with calculated elimination half-lives of 1.3-15.4h and metabolic yields up to 2.7 mol%. In five-day and 23-day inhalation studies and a 90-day oral study of 6:2 FTOH, the plasma or serum concentration profile of 5:3 Acid was several-fold higher than concentrations observed in the single day study, resulting in an estimated elimination half-life of 20-30 d. In contrast, the concentrations of PFBA, PFHxA and PFHpA showed little or no concentration increase with repeated exposure. Elimination half-lives of PFHxA, PFHpA and 5:3 Acid in humans were estimated from a study of professional ski wax technicians who were occupationally exposed to aerosolized and volatilized components of fluorinated glide wax. The resulting human elimination half-life values of PFHxA, PFHpA and 5:3 Acid were 32, 70 and 43 d, respectively. Based on a one compartment toxicokinetic model, current environmental air concentrations of 6:2 FTOH are estimated to result in plasma concentrations of PFHxA, PFHpA and 5:3 Acid that are less than or equal to typical LOQ values, in agreement with extant biomonitoring results.
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Affiliation(s)
- Mark H Russell
- DuPont Haskell Centers for Health and Environmental Sciences, E. I. duPont de Nemours and Company, Inc., 1090 Elkton Road, Newark, DE 19711-3507, USA.
| | - Matthew W Himmelstein
- DuPont Haskell Centers for Health and Environmental Sciences, E. I. duPont de Nemours and Company, Inc., 1090 Elkton Road, Newark, DE 19711-3507, USA
| | - Robert C Buck
- E. I. duPont de Nemours and Company, Inc., Chemicals and Fluoroproducts, 974 Centre Road, Wilmington, DE 19805, USA
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Mukerji P, Rae JC, Buck RC, O'Connor JC. Oral repeated-dose systemic and reproductive toxicity of 6:2 fluorotelomer alcohol in mice. Toxicol Rep 2014; 2:130-143. [PMID: 28962345 PMCID: PMC5598097 DOI: 10.1016/j.toxrep.2014.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/01/2014] [Accepted: 12/01/2014] [Indexed: 01/28/2023] Open
Abstract
6:2 fluorotelomer alcohol (6:2 FTOH) was evaluated for potential systemic repeated-dose and reproductive toxicity in mice. 6:2 FTOH was administered by oral gavage to CD-1 mice as a suspension in 0.5% aqueous methylcellulose with 0.1% Tween-80 at dosages of 1, 5, 25, or 100 mg/kg/day. The no-observed-adverse-effect level (NOAEL) for systemic toxicity was 25 mg/kg/day (males) and 5 mg/kg/day (females), based on effects at higher doses on mortality, clinical observations, body weight, nutritional parameters, hematology (red and white blood cell), clinical chemistry (liver-related), liver weights, and histopathology (liver, teeth, reproductive tract, and mammary gland). However, 6:2 FTOH was not a selective reproductive toxicant. The NOAEL for reproductive toxicity was >100 mg/kg/day; no effects on reproductive outcome were observed at any dosage. The NOAEL for viability and growth of the offspring was 25 mg/kg/day, based on clinical signs of delayed maturation in pups, and reductions in pup survival and pup body weight during lactation at 100 mg/kg/day. While the severity of the effects was generally greater in mice than previously reported in CD rats, the overall NOAELs were identical in both species, 5 mg/kg/day for systemic toxicity and 25 mg/kg/day for offspring viability/growth. 6:2 FTOH was not a selective reproductive toxicant in either species; no effects on reproductive outcome occurred at any dose level, and any effects observed in offspring occurred at dose levels that induced mortality and severe toxicity in maternal animals.
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Affiliation(s)
- Pushkor Mukerji
- E I. duPont de Nemours and Company, Inc., Haskell Global Centers for Health & Environmental Sciences, P.O. Box 30, Newark, DE 19714, United States
| | - Jessica Caverly Rae
- E I. duPont de Nemours and Company, Inc., Haskell Global Centers for Health & Environmental Sciences, P.O. Box 30, Newark, DE 19714, United States
| | - Robert C Buck
- E I. duPont de Nemours and Company, Inc., Chemicals and Fluoroproducts, Wilmington, DE 19805, United States
| | - John C O'Connor
- E I. duPont de Nemours and Company, Inc., Haskell Global Centers for Health & Environmental Sciences, P.O. Box 30, Newark, DE 19714, United States
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Ruan T, Sulecki LM, Wolstenholme BW, Jiang G, Wang N, Buck RC. 6:2 Fluorotelomer iodide in vitro metabolism by rat liver microsomes: comparison with [1,2-(14)C] 6:2 fluorotelomer alcohol. Chemosphere 2014; 112:34-41. [PMID: 25048885 DOI: 10.1016/j.chemosphere.2014.02.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 02/20/2014] [Accepted: 02/22/2014] [Indexed: 06/03/2023]
Abstract
6:2 Fluorotelomer iodide [6:2 FTI, F(CF2)6CH2CH2I] is the industrial raw material used to manufacture 6:2 fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] and 6:2 FTOH-based products. During its manufacture and industrial use, workers may be exposed to via oral, dermal or inhalation of 6:2 FTI. Therefore it is useful to understand how 6:2 FTI may be metabolized and into what transformation products. 6:2 FTI in vitro rat liver microsomal metabolism was explored for the first time to compare its biotransformation potential with that of [1,2-(14)C] 6:2 FTOH [F(CF2)6(14)CH2(14)CH2OH]. 6:2 FTI and 6:2 FTOH metabolite yields were determined in closed-bottle systems using Sprague Dawley and Wistar Han rat microsomes after incubation at 37 °C for up to 6h with NADPH (reduced form of nicotinamide adenine dinucleotide phosphate)-addition and NADPH-regenerating systems, respectively. 5:3 acid [F(CF2)5CH2CH2COOH] was the most abundant metabolite for 6:2 FTI (3.3-6.3 mol%) and 6:2 FTOH (9-12 mol%). Perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), and perfluorohexanoic acid (PFHxA) in sum accounted for 1.3-2.2 mol% from 6:2 FTI and 2.7-4.4 mol% from 6:2 FTOH biotransformation. Perfluoroheptanoic acid (PFHpA) accounted for 0.14-0.36 mol% from 6:2 FTI but only 0.01-0.06 mol% from 6:2 FTOH biotransformation. These results suggest that mammalian systems exposed to 6:2 FTI or 6:2 FTOH would form 5:3 acid, PFBA, PFPeA, PFHxA as the primary stable metabolites, whereas more PFHpA would be expected from 6:2 FTI biotransformation.
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Affiliation(s)
- Ting Ruan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
| | - Lisa M Sulecki
- E.I. du Pont de Nemours & Company, Inc., Newark, DE, USA
| | | | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
| | - Ning Wang
- E.I. du Pont de Nemours & Company, Inc., Newark, DE, USA.
| | - Robert C Buck
- E.I. du Pont de Nemours & Company, Inc., Newark, DE, USA
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12
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Wang Z, Cousins IT, Scheringer M, Buck RC, Hungerbühler K. Global emission inventories for C4-C14 perfluoroalkyl carboxylic acid (PFCA) homologues from 1951 to 2030, Part I: production and emissions from quantifiable sources. Environ Int 2014; 70:62-75. [PMID: 24932785 DOI: 10.1016/j.envint.2014.04.013] [Citation(s) in RCA: 409] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 04/07/2014] [Accepted: 04/08/2014] [Indexed: 05/21/2023]
Abstract
We quantify global emissions of C4-C14 perfluoroalkyl carboxylic acid (PFCA) homologues during the life-cycle of products based on perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctane sulfonyl fluoride (POSF), and fluorotelomer compounds. We estimate emissions of 2610-21400 tonnes of C4-C14 PFCAs in the period from 1951 to 2015, and project 20-6420 tonnes to be emitted from 2016 to 2030. The global annual emissions steadily increased in the period 1951-2002, followed by a decrease and then another increase in the period 2002-2012. Releases from fluoropolymer production contributed most to historical PFCA emissions (e.g. 55-83% in 1951-2002). Since 2002, there has been a geographical shift of industrial sources (particularly fluoropolymer production sites) from North America, Europe and Japan to emerging Asian economies, especially China. Sources differ between PFCA homologues, sometimes considerably, and the relative contributions of each source change over time. For example, whereas 98-100% of historical (1951-2002) PFOA emissions are attributed to direct releases during the life-cycle of products containing PFOA as ingredients or impurities, a much higher historical contribution from PFCA precursor degradation is estimated for some other homologues (e.g. 9-78% for PFDA). We address the uncertainties of the PFCA emissions by defining a lower and a higher emission scenario, which differ by approximately a factor of eight.
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Affiliation(s)
- Zhanyun Wang
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Ian T Cousins
- Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden
| | - Martin Scheringer
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
| | - Robert C Buck
- E.I. du Pont de Nemours & Co. Inc., DuPont Chemicals and Fluoroproducts, 974 Centre Road, CRP 702-2211B, Wilmington, DE 19880-0702 USA
| | - Konrad Hungerbühler
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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13
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Wang Z, Cousins IT, Scheringer M, Buck RC, Hungerbühler K. Global emission inventories for C4-C14 perfluoroalkyl carboxylic acid (PFCA) homologues from 1951 to 2030, part II: the remaining pieces of the puzzle. Environ Int 2014; 69:166-76. [PMID: 24861268 DOI: 10.1016/j.envint.2014.04.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 05/17/2023]
Abstract
We identify eleven emission sources of perfluoroalkyl carboxylic acids (PFCAs) that have not been discussed in the past. These sources can be divided into three groups: [i] PFCAs released as ingredients or impurities, e.g., historical and current use of perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA) and their derivatives; [ii] PFCAs formed as degradation products, e.g., atmospheric degradation of some hydrofluorocarbons (HFCs) and hydrofluoroethers (HFEs); and [iii] sources from which PFCAs are released as both impurities and degradation products, e.g., historical and current use of perfluorobutane sulfonyl fluoride (PBSF)- and perfluorohexane sulfonyl fluoride (PHxSF)-based products. Available information confirms that these sources were active in the past or are still active today, but due to a lack of information, it is not yet possible to quantify emissions from these sources. However, our review of the available information on these sources shows that some of the sources may have been significant in the past (e.g., the historical use of PFBA-, PFHxA-, PBSF- and PHxSF-based products), whereas others can be significant in the long-term (e.g., (bio)degradation of various side-chain fluorinated polymers where PFCA precursors are chemically bound to the backbone). In addition, we summarize critical knowledge and data gaps regarding these sources as a basis for future research.
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Affiliation(s)
- Zhanyun Wang
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Ian T Cousins
- Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden
| | - Martin Scheringer
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
| | - Robert C Buck
- E.I. du Pont de Nemours & Co. Inc., DuPont Chemicals and Fluoroproducts, 974 Centre Road, CRP 702-2211B, Wilmington, DE 19880-0702, USA
| | - Konrad Hungerbühler
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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14
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Serex T, Anand S, Munley S, Donner EM, Frame SR, Buck RC, Loveless SE. Toxicological evaluation of 6:2 fluorotelomer alcohol. Toxicology 2014; 319:1-9. [PMID: 24576572 DOI: 10.1016/j.tox.2014.01.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 01/10/2014] [Accepted: 01/29/2014] [Indexed: 11/30/2022]
Abstract
6:2 fluorotelomer alcohol (6:2 FTOH; CF3[CF2]5[CH2]2OH, CAS# 647-42-7) was evaluated for acute, genetic, and subchronic toxicity using in vitro and in vivo methods. In rats, 6:2 FTOH was considered to be slightly toxic by the oral (LD50=1,750 mg/kg), and dermal (LD50 > 5,000 mg/kg) routes. In rabbits, 6:2 FTOH was not a primary skin or eye irritant, and it did not produce a dermal sensitization response in mice. In a 90-day subchronic study, 6:2 FTOH was administered to rats by oral gavage (0, 5, 25, 125, 250 mg/kg/day). Mortality was observed at 125 and 250 mg/kg/day; deaths occurred after approximately three weeks of dosing and continued sporadically. The NOAEL in the subchronic study was 5mg/kg/day based on hematology and liver effects. 6:2 FTOH was not mutagenic in the bacterial reverse mutation test or in the mouse lymphoma assay and was not clastogenic in a chromosome aberration assay in human lymphocytes. The hazard classification for human health endpoints of 6:2 FTOH according to the United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is Category 4 for acute oral toxicity based on an LD50 of 1,750 mg/kg. Other acute health endpoints including eye and skin irritation, skin sensitization, as well as genotoxicity, did not meet the criteria for hazard classification. Benchmark Dose Analysis was performed on the most sensitive endpoints from the 90-day oral gavage study and these levels were all above the study NOAEL of 5mg/kg/day. For risk assessment purposes, the recommended point of departure is the more conservative study NOAEL of 5mg/kg/day.
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Affiliation(s)
- Tessa Serex
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA; DuPont Crop Protection, Newark, DE, USA
| | - Satheesh Anand
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA
| | - Susan Munley
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA
| | - E Maria Donner
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA
| | - Steven R Frame
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA
| | - Robert C Buck
- E. I. duPont de Nemours and Company, Inc., Chemicals and Fluoroproducts, Wilmington, DE, USA
| | - Scott E Loveless
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE, USA.
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15
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Russell MH, Nilsson H, Buck RC. Elimination kinetics of perfluorohexanoic acid in humans and comparison with mouse, rat and monkey. Chemosphere 2013; 93:2419-2425. [PMID: 24050716 DOI: 10.1016/j.chemosphere.2013.08.060] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 08/12/2013] [Accepted: 08/16/2013] [Indexed: 05/27/2023]
Abstract
Major fluorinated chemical manufacturers have developed new short-chain per- and polyfluorinated substances with more favorable environmental, health and safety profiles. This study provides the first evaluation of the elimination half-life of perfluorohexanoic acid (PFHxA) from the blood of humans. PFHxA biomonitoring data were obtained from a recently published study of professional ski wax technicians. These data were analyzed to provide estimates of the apparent half-life of PFHxA from humans, and comparisons were made with kinetic studies of PFHxA elimination from mice, rats and monkeys. The apparent elimination half-life of PFHxA in highly exposed humans ranged between 14 and 49 d with a geomean of 32 d. The half-lives of PFHxA in mice, rats, monkeys and humans were proportional to body weight with no differences observed between genders, indicating similar volumes of distribution and similar elimination mechanisms among mammalian species. Compared to long-chain perfluoroalkyl acid analogs, PFHxA is rapidly cleared from biota. The consistent weight-normalized elimination half-lives for PFHxA in mammalian species indicates that results obtained from animal models are suitable for establishment of PFHxA benchmark dose and reference dose hazard endpoints for use in human risk assessments.
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Affiliation(s)
- Mark H Russell
- DuPont Haskell Global Centers for Health and Environmental Sciences, S320/214, P.O. Box 50, Newark, DE, USA.
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16
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Ruan T, Szostek B, Folsom PW, Wolstenholme BW, Liu R, Liu J, Jiang G, Wang N, Buck RC. Aerobic soil biotransformation of 6:2 fluorotelomer iodide. Environ Sci Technol 2013; 47:11504-11511. [PMID: 24021083 DOI: 10.1021/es4018128] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
6:2 FTI [F(CF2)6CH2CH2I] is a principal industrial raw material used to manufacture 6:2 FTOH [F(CF2)6CH2CH2OH] and 6:2 FTOH-based products and could enter aerobic environments from possible industrial emissions where it is manufactured. This is the first study to assess 6:2 FTI aerobic soil biotransformation, quantify transformation products, and elucidate its biotransformation pathways. 6:2 FTI biotransformation led to 6:2 FTOH as a key intermediate, which was subsequently biotransformed to other significant transformation products, including PFPeA [F(CF2)4COOH, 20 mol % at day 91], 5:3 acid [F(CF2)5CH2CH2COOH, 16 mol %], PFHxA [F(CF2)5COOH, 3.8 mol %], and 4:3 acid [F(CF2)4CH2CH2COOH, 3.0 mol %]. 6:2 FTI biotransformation also led to a significant level of PFHpA [F(CF2)6COOH, 16 mol % at day 91], perhaps via another putative intermediate, 6:2 FTUI [F(CF2)6CH ═ CHI], whose molecular identity and further biotransformation were not verified because of the lack of an authentic standard. Total recovery of the aforementioned per- and polyfluorocarboxylates accounted for 59 mol % of initially applied 6:2 FTI by day 91, in comparison to 56 mol % when soil was dosed with 6:2 FTOH, which did not lead to PFHpA. Thus, were 6:2 FTI to be released from its manufacture and undergo soil microbial biotransformation, it could form PFPeA, PFHpA, PFHxA, 5:3 acid, and 4:3 acid in the environment.
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Affiliation(s)
- Ting Ruan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Post Office Box 2871, Beijing 100085, People's Republic of China
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17
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Zhao L, McCausland PK, Folsom PW, Wolstenholme BW, Sun H, Wang N, Buck RC. 6:2 Fluorotelomer alcohol aerobic biotransformation in activated sludge from two domestic wastewater treatment plants. Chemosphere 2013; 92:464-470. [PMID: 23540810 DOI: 10.1016/j.chemosphere.2013.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 02/13/2013] [Accepted: 02/16/2013] [Indexed: 06/02/2023]
Abstract
6:2 Fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] is a major basic chemical being used to manufacture FTOH-based products. After the end of use, 6:2 FTOH-based products may be released to domestic wastewater treatment plants (WWTPs) as a first major environmental entry point. Activated sludge collected from two WWTPs was dosed with 6:2 FTOH to investigate its biotransformation rate and to identify major transformation products. The volatile 5:2 sFTOH [F(CF2)5CH(OH)CH3] is the most abundant transformation product and accounted for an average of 40mol% of initially dosed 6:2 FTOH after two months of incubation with activated sludge, with 30mol% detected in the headspace. PFPeA [F(CF2)4COOH] averaged 4.4mol% after two months, 2.4-7 times lower than that in sediment and soils. The much lower level of PFPeA formed in activated sludge compared with soil indicates that microbial populations in activated sludge may lack enzymes or suitable environment conditions to promote rapid 5:2 sFTOH decarboxylation to form PFPeA, resulting in more 5:2 sFTOH partitioned to the headspace. PFHxA [F(CF2)5COOH] and 5:3 [F(CF2)5CH2CH2COOH] acid are major non-volatile transformation products in activated sludge. For example, PFHxA averaged 11mol% after two months, which is about 30% higher compared with sediment and soils, suggesting that microbes in WWTPs may utilize similar pathways as that in sediment and soils to convert 5:2 sFTOH to PFHxA. 5:3 Acid averaged 14mol% after two months, comparable to that in soils and slightly lower than in sediment, further confirming that 5:3 acid is a unique product of 6:2 FTOH biotransformation in the environment.
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Affiliation(s)
- Lijie Zhao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, China
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18
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Zhang S, Szostek B, McCausland PK, Wolstenholme BW, Lu X, Wang N, Buck RC. 6:2 and 8:2 fluorotelomer alcohol anaerobic biotransformation in digester sludge from a WWTP under methanogenic conditions. Environ Sci Technol 2013; 47:4227-35. [PMID: 23531206 DOI: 10.1021/es4000824] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
6:2 FTOH and 8:2 FTOH [FTOHs, F(CF2)nCH2CH2OH, n = 6, 8] are the principal polyfluorinated raw materials used to manufacture FTOH-based products, which may be released to WWTPs during their product life cycle. For the first time, anaerobic biotransformation of FTOHs and key biotransformation intermediates in WWTP digester sludge under methanogenic conditions was investigated. 6:2 FTOH was transformed to 6:2 FTCA, [F(CF2)6CH2COOH, 32-43 mol %], 6:2 FTUCA [F(CF2)5CF═CHCOOH, 1.8-8.0 mol %], and 5:3 acid [F(CF2)5CH2CH2COOH, 18-23 mol %] by day 90 and day 176 in two separate studies. 8:2 FTOH was transformed by day 181 to 8:2 FTCA (18 mol %), 8:2 FTUCA (5.1 mol %), and 7:3 acid (27 mol %). 6:2 and 8:2 FTOH anaerobic biotransformation led to low levels of perfluorohexanoic acid (PFHxA, ≤0.4 mol %) and perfluorooctanoic acid (PFOA, 0.3 mol %), respectively. 6:2 FTUCA anaerobic biotransformation led to a newly identified novel transient intermediate 3-fluoro 5:3 acid [F(CF2)5CFHCH2COOH] and 5:3 acid, but not 5:2 sFTOH [F(CF2)5CH(OH)CH3] and α-OH 5:3 acid [F(CF2)5CH2CH(OH)COOH], two precursors leading to PFPeA (perfluoropentanoic acid) and PFHxA. Thus, FTOH anaerobic biotransformation pathways operated by microbes in the environment was likely inefficient at shortening carbon chains of FTOHs to form PFCAs (perfluorinated carboxylic acids). These results imply that anaerobic biotransformation of FTOH-based products may produce polyfluorinated acids, but is not likely a major source of PFCAs detected in anaerobic environmental matrices such as anaerobic digester sludge, landfill leachate, and anaerobic sediment under methanogenic conditions.
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Affiliation(s)
- Shu Zhang
- Laboratory for Earth Surface Processes, Ministry of Education, College of Urban and Environmental Sciences, Peking University, Beijing, China
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19
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Zhao L, Folsom PW, Wolstenholme BW, Sun H, Wang N, Buck RC. 6:2 fluorotelomer alcohol biotransformation in an aerobic river sediment system. Chemosphere 2013; 90:203-209. [PMID: 22840539 DOI: 10.1016/j.chemosphere.2012.06.035] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/21/2012] [Accepted: 06/26/2012] [Indexed: 06/01/2023]
Abstract
The 6:2 FTOH [F(CF(2))(6)CH(2)CH(2)OH] is a major raw material being used to replace 8:2 FTOH [F(CF(2))(8)CH(2)CH(2)OH] to make FTOH-based products for industrial and consumer applications. A novel aerobic sediment experimental system containing 20 g wet sediment and 30 mL aqueous solution was developed to study 6:2 FTOH biotransformation in river sediment. 6:2 FTOH was dosed into the sediment to follow its biotransformation and to analyze transformation products over 100 d. The primary 6:2 FTOH biotransformation in the aerobic sediment system was rapid (T(1/2)<2d). 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH] was observed as the predominant polyfluorinated acid on day 100 (22.4 mol%), higher than the sum of perfluoropentanoic acid (10.4 mol%), perfluorohexanoic acid (8.4 mol%), and perfluorobutanoic acid (1.5 mol%). Perfluoroheptanoic acid was not observed during 6:2 FTOH biotransformation. The 5:3 acid can be further degraded to 4:3 acid [F(CF(2))(4)CH(2)CH(2)COOH, 2.7 mol%]. This suggests that microbes in the river sediment selectively degraded 6:2 FTOH more toward 5:3 and 4:3 acids compared with soil. Most of the observed 5:3 acid formed bound residues with sediment organic components and can only be quantitatively recovered by post-treatment with NaOH and ENVI-Carb™ carbon. The 6:2 FTCA [F(CF(2))(6)CH(2)COOH], 6:2 FTUCA [F(CF(2))(5)CF=CHCOOH], 5:2 ketone [F(CF(2))(5)C(O)CH(3)], and 5:2 sFTOH [F(CF(2))(5)CH(OH)CH(3)] were major transient intermediates during 6:2 FTOH biotransformation in the sediment system. These results suggest that if 6:2 FTOH or 6:2 FTOH-based materials were released to the river or marine sediment, poly- and per-fluorinated carboxylates could be produced.
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Affiliation(s)
- Lijie Zhao
- MOE Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin, China
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Hoke RA, Bouchelle LD, Ferrell BD, Buck RC. Comparative acute freshwater hazard assessment and preliminary PNEC development for eight fluorinated acids. Chemosphere 2012; 87:725-33. [PMID: 22280982 DOI: 10.1016/j.chemosphere.2011.12.066] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 05/20/2023]
Abstract
Short-term 48, 72 and 96-h aquatic toxicity tests were conducted to evaluate the acute toxicity of eight fluorinated acids to the cladoceran, Daphnia magna, the green alga, Pseudokirchneriella subcapitata, and the rainbow trout, Oncorhynchus mykiss or the fathead minnow, Pimephales promelas. The eight fluorinated acids studied were tridecafluorohexyl ethanoic acid (6:2 FTCA), heptadecafluorooctyl ethanoic acid (8:2 FTCA), 2H-dodecafluoro-2-octenoic acid (6:2 FTUCA), 2H-hexadecafluoro-2-decenoic acid (8:2 FTUCA), 2H,2H,3H,3H-undecafluoro octanoic acid (5:3 acid), 2H,2H,3H,3H-pentadecafluoro decanoic acid (7:3 acid), n-perfluoropentanoic acid (PFPeA) and n-perfluorodecanoic acid (PFDA). The results of the acute toxicity tests conducted during this study suggest that the polyfluorinated acids, 8:2 FTCA, 8:2 FTUCA, 6:2 FTCA, 6:2 FTUCA, 7:3 acid and 5:3 acid, and the perfluorinated acids PFPeA and PFDA, are generally of low to medium concern based on evaluation of their acute freshwater toxicity (EC/LC50s typically between 1 and >100 mg L(-1)) using the USEPA TSCA aquatic toxicity evaluation paradigm. For the polyfluorinated acids, aquatic toxicity generally decreased as the number of fluorinated carbons decreased and as the overall carbon chain length decreased from 12 to 8. Acute aquatic toxicity of the 5 and 10 carbon perfluorocarboxylic acids (EC/LC50s between 10.6 and >100 mg L(-1)) was greater or similar to that of the 6-9 carbon perfluorocarboxylic acids (EC/LC50s>96.5 mg L(-1)). This study also provides the first report of the acute aquatic toxicity of the 5:3 acid (EC/LC50s of 22.5 to >103 mg L(-1)) which demonstrated less aquatic toxicity than the 7:3 acid (EC/LC50s of 0.4-32 mg L(-1)). The cladoceran, D. magna and the green alga, P. subcapitata had generally similar EC50 values for a given substance while fish were typically equally or less sensitive with the exception that PFPeA was most toxic to fish. Predicted no-effect concentrations (PNECs) were estimated using approaches consistent with REACH guidance and when compared with available environmental concentrations, these PNECs suggest that the fluorinated acids tested pose little risk for aquatic organisms.
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Affiliation(s)
- Robert A Hoke
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19714, USA.
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21
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Wang N, Buck RC, Szostek B, Sulecki LM, Wolstenholme BW. 5:3 Polyfluorinated acid aerobic biotransformation in activated sludge via novel "one-carbon removal pathways". Chemosphere 2012; 87:527-534. [PMID: 22264858 DOI: 10.1016/j.chemosphere.2011.12.056] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 12/20/2011] [Accepted: 12/22/2011] [Indexed: 05/27/2023]
Abstract
The polyfluorinated carboxylic acids 5:3 acid (C(5)F(11)CH(2)CH(2)CO(2)H) and 7:3 acid (C(7)F(15)CH(2)CH(2)CO(2)H) are major products from 6:2 FTOH (C(6)F(13)CH(2)CH(2)OH) and 8:2 FTOH (C(8)F(17)CH(2)CH(2)OH) aerobic biotransformation, respectively. The 5:3 and 7:3 acids were dosed into domestic WWTP activated sludge for 90 d to determine their biodegradability. The 7:3 acid aerobic biodegradability was low, only 1.7 mol% conversion to perfluoroheptanoic acid (PFHpA), whereas no transformation was observed previously in soil. In stark contrast, 5:3 acid aerobic biodegradability was enhanced 10 times in activated sludge compared to soil. The 5:3 acid was not activated by acyl CoEnzyme A (CoA) synthetase, a key step required for further α- or ß-oxidation. Instead, 5:3 acid was directly converted to 4:3 acid (C(4)F(9)CH(2)CH(2)CO(2)H, 14.2 mol%) and 3:3 acid (C(3)F(7)CH(2)CH(2)CO(2)H, 0.9 mol%) via "one-carbon removal pathways". The 5:3 acid biotransformation also yielded perfluoropentanoic acid (PFPeA, 5.9 mol%) and perfluorobutanoic acid (PFBA, 0.8 mol%). This is the first report to identify key biotransformation intermediates which demonstrate novel one-carbon removal pathways with sequential removal of CF(2) groups. Identified biotransformation intermediates (10.2 mol% in sum) were 5:3 Uacid, α-OH 5:3 acid, 5:2 acid, and 5:2 Uacid. The 5:2 Uacid and 5:2 acid are novel intermediates identified for the first time which confirm the proposed pathways. In the biodegradation pathways, the genesis of the one carbon removal is CO(2) elimination from α-OH 5:3 acid. These results suggest that there are enzymatic mechanisms available in the environment that can lead to 6:2 FTOH and 5:3 acid mineralization. The dehydrogenation from 5:3 acid to 5:3 Uacid was the rate-limiting enzymatic step for 5:3 acid conversion to 4:3 acid.
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Affiliation(s)
- Ning Wang
- E.I. du Pont De Nemours & Company, Inc., Wilmington, DE, USA.
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22
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Anand SS, Serex TL, Carpenter C, Donner EM, Hoke R, Buck RC, Loveless SE. Toxicological assessment of tridecafluorohexylethyl methacrylate (6:2 FTMAC). Toxicology 2012; 292:42-52. [DOI: 10.1016/j.tox.2011.11.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/14/2011] [Accepted: 11/23/2011] [Indexed: 11/25/2022]
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Cousins IT, Buck RC. Letter to the editor regarding, "Polyfluorinated compounds: past, present, and future". Environ Sci Technol 2011; 45:9821. [PMID: 22035063 DOI: 10.1021/es203530y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Himmelstein MW, Serex TL, Buck RC, Weinberg JT, Mawn MP, Russell MH. 8:2 fluorotelomer alcohol: a one-day nose-only inhalation toxicokinetic study in the Sprague-Dawley rat with application to risk assessment. Toxicology 2011; 291:122-32. [PMID: 22120539 DOI: 10.1016/j.tox.2011.11.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 11/10/2011] [Accepted: 11/11/2011] [Indexed: 11/30/2022]
Abstract
8:2 fluorotelomer alcohol (8:2 FTOH) inhalation exposure was investigated to (1) compare plasma metabolites to oral data, (2) conduct a route-to-route extrapolation (oral to inhalation), (3) develop a human equivalent air concentration (HEC) from a 90-day oral sub-chronic study in rats using BMD analysis, and (4) calculate a margin of exposure (MOE) between the HEC and measured air concentrations. Male and female rats were exposed nose-only for 6h at 3 or 30mg/m(3). Blood was collected at 1, 3 and 6h during exposure and 6 and 18h post exposure. Alcohol, perfluorocarboxylic acid and polyfluorinated acid metabolites were determined in plasma by LC-MS/MS. 8:2 FTOH was <LOQ (32nM) at the low exposure and quantifiable (37-69nM) at the high exposure. The quantifiable metabolites in plasma were dose proportional and comprised mainly of 8:2 FTCA, 7:3 Acid, and PFOA. By kinetic modeling, the yields of the terminal products 7:3 Acid (1.6-2.1 and 0.9mol%) and PFOA (1.0-1.2 and 0.3mol%) of the inhaled dose were low for male and female rats, respectively. The kinetic yield of PFOA after oral dosing was similar (1.1-1.7-fold) for male rats and greater (8-9-fold) for female rats relative to inhalation exposure, an observation confirmed by non-compartmental analysis. A BMDL10% (3.7mg/kg/day) was derived for mild hepatic necrosis observed in male rats following a 90-day oral dose study with 8:2 FTOH. The corresponding HECs were 1.8 and 3.7mg/m(3), which gave MOE values ranging from 1.8×10(4) to 6.1×10(6) based on reported ambient air concentrations of 0.3-209ng/m(3). These findings demonstrate rapid 8:2 FTOH uptake and clearance by the inhalation route and a consistent metabolite profile between inhalation and oral exposures in rats. No toxicity is expected in humans from typical ambient 8:2 FTOH air exposures.
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Affiliation(s)
- Matthew W Himmelstein
- E.I. DuPont de Nemours and Company, Inc., Haskell Global Centers for Health and Environmental Sciences, Newark, DE 19714-0050, USA.
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Buck RC, Franklin J, Berger U, Conder JM, Cousins IT, de Voogt P, Jensen AA, Kannan K, Mabury SA, van Leeuwen SPJ. Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins. Integr Environ Assess Manag 2011; 7:513-41. [PMID: 21793199 PMCID: PMC3214619 DOI: 10.1002/ieam.258] [Citation(s) in RCA: 2072] [Impact Index Per Article: 159.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 05/26/2011] [Accepted: 07/05/2011] [Indexed: 05/18/2023]
Abstract
The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers.
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Affiliation(s)
- Robert C Buck
- E.I. du Pont de Nemours & Co., Inc., DuPont Chemicals and FluoroproductsWilmington, Delaware, USA
| | - James Franklin
- CLF-Chem Consulting3 Clos du Châtaignier, BE-1390 Grez-Doiceau, Belgium
| | - Urs Berger
- Department of Applied Environmental Science (ITM), Stockholm UniversityStockholm, Sweden
| | | | - Ian T Cousins
- Department of Applied Environmental Science (ITM), Stockholm UniversityStockholm, Sweden
| | - Pim de Voogt
- Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, The Netherlands
| | - Allan Astrup Jensen
- Nordic Institute for Product Sustainability, Environmental Chemistry and Toxicology (NIPSECT)Frederiksberg, Denmark
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at AlbanyAlbany, New York, USA
| | - Scott A Mabury
- Department of Chemistry, University of TorontoToronto, Ontario, Canada
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Gannon SA, Johnson T, Nabb DL, Serex TL, Buck RC, Loveless SE. Absorption, distribution, metabolism, and excretion of [1-¹⁴C]-perfluorohexanoate ([¹⁴C]-PFHx) in rats and mice. Toxicology 2011; 283:55-62. [PMID: 21349313 DOI: 10.1016/j.tox.2011.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/09/2011] [Accepted: 02/15/2011] [Indexed: 01/09/2023]
Abstract
The absorption, tissue distribution, elimination, and metabolism of [1-¹⁴C]-PFHx in rats and mice dosed orally at 2 or 100 mg/kg was evaluated following a single dose or after 14 consecutive doses. Absorption was rapid in rats as evidenced by a short time to maximum concentration (C(max)) of 30 min in male rats and 15 min in female rats at both the 2 and 100mg/kg dose level. The plasma elimination half-life was somewhat longer in males (1.5-1.7 h) than in females (0.5-0.7 h). Absorption in the mouse was also rapid with the maximum plasma concentration occurring between 15 and 30 min after dosing. The maximum concentration was not appreciably different between male and female mice (8 μg equiv./g at 2 mg/kg; ~350 μg equiv./g at 100 mg/kg). The primary route of elimination was via the urine. PFHx was not metabolized in rat or mouse hepatocytes, nor were any metabolites observed after oral dosing in either rodent species. Essentially 100% of the dose was eliminated in urine within 24 h demonstrating that PFHx is readily absorbed and bioavailability approaches 100%, even at a dose as high as 100 mg/kg. The route and extent of elimination was unchanged after 14 days of daily dosing. Tissues were collected at three time points (rat: 0.5, 2, and 24 h; mice: 0.25, 1, and 24 h) after dosing to investigate the tissue clearance kinetics of PFHx following a single dose at 2 or 100 mg/kg. In all tissues except skin, PFHx was not quantifiable 24 h after dosing in both sexes of the two species.
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Affiliation(s)
- Shawn A Gannon
- DuPont Haskell Global Centers for Health and Environmental Sciences, Elkton Rd, Newark, DE 19714-0050, USA.
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Wang N, Liu J, Buck RC, Korzeniowski SH, Wolstenholme BW, Folsom PW, Sulecki LM. 6:2 fluorotelomer sulfonate aerobic biotransformation in activated sludge of waste water treatment plants. Chemosphere 2011; 82:853-8. [PMID: 21112609 DOI: 10.1016/j.chemosphere.2010.11.003] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/29/2010] [Accepted: 11/01/2010] [Indexed: 05/03/2023]
Abstract
The aerobic biotransformation of 6:2 FTS salt [F(CF2)6CH2CH2SO3- K+] was determined in closed bottles for 90d in diluted activated sludge from three waste water treatment plants (WWTPs) to compare its biotransformation potential with that of 6:2 FTOH [F(CF2)6CH2CH2OH]. The 6:2 FTS biotransformation was relatively slow, with 63.7% remaining at day 90 and all observed transformation products together accounting for 6.3% of the initial 6:2 FTS applied. The overall mass balance (6:2 FTS plus observed transformation products) at day 90 in live and sterile treatments averaged 70% and 94%, respectively. At day 90, the stable transformation products observed were 5:3 acid [F(CF2)5CH2CH2COOH, 0.12%], PFBA [F(CF2)3COOH, 0.14%], PFPeA [F(CF2)4COOH, 1.5%], and PFHxA [F(CF2)5COOH 1.1%]. In addition, 5:2 ketone [F(CF2)5C(O)CH3] and 5:2 sFTOH [F(CF2)5CH(OH)CH3] together accounted for 3.4% at day 90. The yield of all the stable transformation products noted above (2.9%) was 19 times lower than that of 6:2 FTOH in aerobic soil. Thus 6:2 FTS is not likely to be a major source of PFCAs and polyfluorinated acids in WWTPs. 6:2 FTOH, 6:2 FTA [F(CF2)6CH2COOH], and PFHpA [F(CF2)6COOH] were not observed during the 90-d incubation. 6:2 FTS primary biotransformation bypassed 6:2 FTOH to form 6:2 FTUA [F(CF2)5CF=CHCOOH], which was subsequently degraded via pathways similar to 6:2 FTOH biotransformation. A substantial fraction of initially dosed 6:2 FTS (24%) may be irreversibly bound to diluted activated sludge catalyzed by microbial enzymes. The relatively slow 6:2 FTS degradation in activated sludge may be due to microbial aerobic de-sulfonation of 6:2 FTS, required for 6:2 FTS further biotransformation, being a rate-limiting step in microorganisms of activated sludge in WWTPs.
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Affiliation(s)
- Ning Wang
- E.I. du Pont De Nemours, Co., Inc., Wilmington, DE, USA.
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Liu J, Wang N, Buck RC, Wolstenholme BW, Folsom PW, Sulecki LM, Bellin CA. Aerobic biodegradation of [14C] 6:2 fluorotelomer alcohol in a flow-through soil incubation system. Chemosphere 2010; 80:716-723. [PMID: 20591465 DOI: 10.1016/j.chemosphere.2010.05.027] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 05/18/2010] [Accepted: 05/19/2010] [Indexed: 05/27/2023]
Abstract
The aerobic biodegradation of [1,2-(14)C] 6:2 FTOH [F(CF(2))(6)(14)CH(2)(14)CH(2)OH] in a flow-through soil incubation system is described. Soil samples dosed with [1,2-(14)C] 6:2 FTOH were analyzed by liquid scintillation counting, LC/ARC (liquid chromatography/accurate radioisotope counting), LC/MS/MS, and thermal combustion to account for 6:2 FTOH and its transformation products over 84 d. Half of the [1,2-(14)C] 6:2 FTOH disappeared from soil in 1.3 d, undergoing simultaneous microbial degradation and partitioning of volatile transformation product(s) and the 6:2 FTOH precursor into the air phase. The overall (14)C (radioactivity) mass balance in live and sterile treatments was 77-87% over 84-d incubation. In the live test system, 36% of total (14)C dosed was captured in the airflow (headspace), 25% as soil-bound residues recovered via thermal combustion, and 16% as soil extractable. After 84 d, [(14)C] 5:2 sFTOH [F(CF(2))(5)CH(OH)(14)CH(3)] was the dominant transformation product with 16% molar yield and primarily detected in the airflow. The airflow also contained [1,2-(14)C] 6:2 FTOH and (14)CO(2) at 14% and 6% of total (14)C dosed, respectively. The other significant stable transformation products, all detected in soil, were 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH, 12%], PFHxA [F(CF(2))(5)COOH, 4.5%] and PFPeA [F(CF(2))(4)COOH, 4.2%]. Soil-bound residues as well as conjugates between fluorinated transformation products and dissolved soil components were only observed in the live test system and absent in the sterile soil, suggesting that such binding and complexation are microbially or enzymatically driven processes. At day 84, 5:3 acid is postulated to be the major transformation product in soil-bound residues, which may not be available for further biodegradation in soil environment.
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Affiliation(s)
- Jinxia Liu
- E.I. du Pont De Nemours & Co., Inc, Wilmington, DE, USA.
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Russell MH, Wang N, Berti WR, Szostek B, Buck RC. Comment on "Degradability of an acrylate-linked, fluorotelomer polymer in soil". Environ Sci Technol 2010; 44:848. [PMID: 20000611 DOI: 10.1021/es902348w] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Russell MH, Berti WR, Szostek B, Wang N, Buck RC. Evaluation of PFO formation from the biodegradation of a fluorotelomer-based urethane polymer product in aerobic soils. Polym Degrad Stab 2010. [DOI: 10.1016/j.polymdegradstab.2009.10.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Liu J, Wang N, Szostek B, Buck RC, Panciroli PK, Folsom PW, Sulecki LM, Bellin CA. 6-2 Fluorotelomer alcohol aerobic biodegradation in soil and mixed bacterial culture. Chemosphere 2010; 78:437-44. [PMID: 19931114 DOI: 10.1016/j.chemosphere.2009.10.044] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/16/2009] [Accepted: 10/19/2009] [Indexed: 05/24/2023]
Abstract
The first studies to explore 6-2 fluorotelomer alcohol [6-2 FTOH, F(CF(2))(6)CH(2)CH(2)OH] aerobic biodegradation are described. Biodegradation yields and metabolite concentrations were determined in mixed bacterial culture (90d) and aerobic soil (180d). 6-2 FTOH primary degradation half-life was less than 2d in both. The overall mass balance in mixed bacterial culture (day 90) was approximately 60%. At day 90, the molar yield was 6% for 6-2 FTA [F(CF(2))(6)CH(2)COOH], 23% for 6-2 FTUA [F(CF(2))(5)CFCHCOOH], 16% for 5-2 sFTOH [F(CF(2))(5)CHOHCH(3)], 6% for 5-3 acid [F(CF(2))(5)CH(2)CH(2)COOH], and 5% for PFHxA [F(CF(2))(5)COOH]. The overall mass balance in aerobic soil was approximately 67% (day 180). At day 180, the major terminal metabolites were PFPeA, [F(CF(2))(4)COOH, 30%], PFHxA (8%), PFBA [F(CF(2))(3)COOH, 2%], and 5-3 acid (15%). A new metabolite 4-3 acid [F(CF(2))(4)CH(2)CH(2)COOH] accounted for 1%, 6-2 FTOH for 3%, and 5-2 sFTOH for 7%. Based on 8-2 FTOH aerobic biodegradation pathways, PFHxA was expected in greatest yield from 6-2 FTOH degradation. However, PFPeA was observed in greatest yield in soil, suggesting a preference for alternate degradation pathways. Selected metabolites were also studied in aerobic soil. 5-3 Acid degraded to only 4-3 acid with a molar yield of 2.3%. 5-2 sFTOH degraded to PFPeA and PFHxA, and 5-2 FT Ketone [F(CF(2))(5)COCH(3)] degraded to 5-2 sFTOH, suggesting that 5-2 sFTOH is the direct precursor to PFPeA and PFHxA. Another new metabolite, 5-3 ketone aldehyde [F(CF(2))(5)COCH(2)CHO] was also identified in mixed bacterial culture. The formation of PFBA, PFPeA, and 4-3 acid indicates that multiple -CF(2)- groups in 6-2 FTOH were removed during microbial biodegradation.
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Affiliation(s)
- Jinxia Liu
- E.I. duPont de Nemours and Co., Inc., Wilmington, DE 19714-6300, USA
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Loveless SE, Slezak B, Serex T, Lewis J, Mukerji P, O’Connor JC, Donner EM, Frame SR, Korzeniowski SH, Buck RC. Toxicological evaluation of sodium perfluorohexanoate. Toxicology 2009; 264:32-44. [DOI: 10.1016/j.tox.2009.07.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 07/10/2009] [Accepted: 07/16/2009] [Indexed: 11/27/2022]
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Wang N, Szostek B, Buck RC, Folsom PW, Sulecki LM, Gannon JT. 8-2 fluorotelomer alcohol aerobic soil biodegradation: pathways, metabolites, and metabolite yields. Chemosphere 2009; 75:1089-96. [PMID: 19217141 DOI: 10.1016/j.chemosphere.2009.01.033] [Citation(s) in RCA: 204] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 01/07/2009] [Accepted: 01/08/2009] [Indexed: 05/19/2023]
Abstract
The biodegradation pathways and metabolite yields of [3-(14)C] 8-2 fluorotelomer alcohol [8-2 FTOH, F(CF(2))(7)(14)CF(2)CH(2)CH(2)OH) in aerobic soils were investigated. Studies were conducted under closed (static) and continuous headspace air flow to assess differences in degradation rate and metabolite concentrations in soil and headspace. Aerobic degradation pathways in soils were in general similar to those in aerobic sludge and bacterial culture. (14)C mass balance was achieved in soils incubated for up to 7 months. Up to 35% (14)C dosed was irreversibly bound to soils and was only recoverable by soil combustion. The average PFOA yield was approximately 25%. Perfluorohexanoic acid (PFHxA) yield reached approximately 4%. (14)CO(2) yield was 6.8% under continuous air flow for 33 days. Three metabolites not previously identified in environmental samples were detected: 3-OH-7-3 acid [F(CF(2))(7)CHOHCH(2)COOH], 7-2 FT ketone [F(CF(2))(7)COCH(3)] and 2H-PFOA [F(CF(2))(6)CFHCOOH]. No perfluorononanoic acid (PFNA) was observed. The formation of 2H-PFOA, PFHxA, and (14)CO(2) shows that multiple -CF(2)- groups were removed from 8-2 FTOH. 7-3 Acid [F(CF(2))(7)CH(2)CH(2)COOH] reached a yield of 11% at day 7 and did not change thereafter. 7-3 Acid was incubated in aerobic soil and did not degrade to PFOA. 7-2 sFTOH [F(CF(2))(7)CH(OH)CH(3)], a transient metabolite, was incubated and degraded principally to PFOA. 7-3 Acid may be a unique metabolite from 8-2 FTOH biodegradation. The terminal ratio of PFOA to 7-3 acid ranged between 1.8-2.5 in soils and 0.6-3.2 in activated sludge, sediment, and mixed bacterial culture. This ratio may be useful in evaluating environmental samples to distinguish the potential contribution of 8-2 FTOH biodegradation to PFOA observed versus PFOA originating from other sources.
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Affiliation(s)
- Ning Wang
- E.I. du Pont De Nemours & Co. Inc., Wilmington, DE, USA.
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Marchione AA, Buck RC. Complete multinuclear magnetic resonance characterization of a set of polyfluorinated acids and alcohols. Magn Reson Chem 2009; 47:194-198. [PMID: 19025971 DOI: 10.1002/mrc.2376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A complete (1)H, (19)F, and (13)C NMR assignment of a homologous series of polyfluorinated acids and alcohols is reported. These assignments were obtained chiefly through single and multiple-bond (1)H-(13)C and (19)F-(13)C correlation experiments (HSQC, HMBC). (19)F NOESY experiments were required for assignment of two compounds with diastereotopic (19)F nuclei in the CF(2)chain of the molecule.
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Affiliation(s)
- Alexander A Marchione
- DuPont Central Research and Development, Experimental Station, Wilmington, DE 19880, USA.
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Stadler JC, Delker DA, Malley LA, Frame SR, Everds NE, Mylchreest E, Munley SM, Loveless SE, Buck RC. Subchronic, reproductive, and developmental toxicity of a fluorotelomer-based urethane polymeric product. Drug Chem Toxicol 2008; 31:317-37. [PMID: 18622868 DOI: 10.1080/01480540701873418] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A commercial fluorotelomer-based urethane polymeric dispersion, consisting of polymer, surfactant, and water, was evaluated in subchronic, reproduction, and developmental toxicity studies. The dispersion was administered daily by gavage to rats at dosages of 0, 50, 250, or 1000 mg polymer/kg/day or with 70 mg/kg/day of the sulfonate surfactant. Dose levels of 0, 50, 250, or 1000 mg polymer/kg/day were also used for the reproductive and developmental studies. Nasal olfactory epithelial degeneration and necrosis occurred in all dose groups in the 90-day study. Nasal adhesions were observed only in rats administered surfactant alone. Liver-enzyme alterations at 250 and 1000 mg/kg were considered to be potentially adverse effects. The subchronic no-observed-adverse-effects level (NOAEL) was 50 mg/kg. For the reproduction study, rats were dosed for 10 weeks prior to cohabitation and throughout mating, gestation, and lactation. There were no effects on reproductive function in males or females at any dosage. Thyroid weight was decreased in the 250 and 1000 mg/kg day F(1) groups unaccompanied by microscopic effects. In the developmental toxicity study, female rats were dosed from gestation days 6-20; there was no test-substance-related embryolethality, nor was there any dose-related increase in either fetal malformations. Fetal weight was minimally decreased at 1000 mg/kg/day in the presence of slight maternal toxicity; the NOAEL for developmental parameters was 250 mg/kg/day. The polymeric product was not a specific developmental or reproductive toxin.
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Affiliation(s)
- Judith C Stadler
- DuPont Haskell Laboratory for Health and Environmental Sciences, Newark, Delaware 19714, USA
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36
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Fasano WJ, Carpenter SC, Gannon SA, Snow TA, Stadler JC, Kennedy GL, Buck RC, Korzeniowski SH, Hinderliter PM, Kemper RA. Absorption, Distribution, Metabolism, and Elimination of 8-2 Fluorotelomer Alcohol in the Rat. Toxicol Sci 2008. [DOI: 10.1093/toxsci/kfn039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Conder JM, Hoke RA, De Wolf W, Russell MH, Buck RC. Are PFCAs bioaccumulative? A critical review and comparison with regulatory criteria and persistent lipophilic compounds. Environ Sci Technol 2008; 42:995-1003. [PMID: 18351063 DOI: 10.1021/es070895g] [Citation(s) in RCA: 742] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Perfluorinated acids, including perfluorinated carboxylates (PFCAs), and perfluorinated sulfonates (PFASs), are environmentally persistent and have been detected in a variety of wildlife across the globe. The most commonly detected PFAS, perfluorooctane sulfonate (PFOS), has been classified as a persistent and bioaccumulative substance. Similarities in chemical structure and environmental behavior of PFOS and the PFCAs that have been detected in wildlife have generated concerns about the bioaccumulation potential of PFCAs. Differences between partitioning behavior of perfluorinated acids and persistent lipophilic compounds complicate the understanding of PFCA bioaccumulation and the subsequent classification of the bioaccumulation potential of PFCAs according to existing regulatory criteria. Based on available research on the bioaccumulation of perfluorinated acids, five key points are highlighted in this review: (1) bioconcentration and bioaccumulation of perfluorinated acids are directly related to the length of each compound's fluorinated carbon chain; (2) PFASs are more bioaccumulative than PFCAs of the same fluorinated carbon chain length; (3) PFCAs with seven fluorinated carbons or less (perfluorooctanoate (PFO) and shorter PFCAs) are not considered bioaccumulative according to the range of promulgated bioaccumulation,"B", regulatory criteria of 1000-5000 L/kg; (4) PFCAs with seven fluorinated carbons or less have low biomagnification potential in food webs, and (5) more research is necessary to fully characterize the bioaccumulation potential of PFCAs with longer fluorinated carbon chains (>7 fluorinated carbons), as PFCAs with longer fluorinated carbon chains may exhibit partitioning behavior similar to or greater than PFOS. The bioaccumulation potential of perfluorinated acids with seven fluorinated carbons or less appears to be several orders of magnitude lower than "legacy" persistent lipophilic compounds classified as bioaccumulative. Thus, although many PFCAs are environmentally persistent and can be present at detectable concentrations in wildlife, it is clear that PFCAs with seven fluorinated carbons or less (including PFO) are not bioaccumulative according to regulatory criteria.
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Affiliation(s)
- Jason M Conder
- ENVIRON International Corporation, 2010 Main Street, Suite 900, Irvine, California 92614, USA
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Russell MH, Berti WR, Szostek B, Buck RC. Investigation of the biodegradation potential of a fluoroacrylate polymer product in aerobic soils. Environ Sci Technol 2008; 42:800-7. [PMID: 18323105 DOI: 10.1021/es0710499] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biodegradation of fluorinated polymers is of interest to assess them as a potential source of perfluorocarboxylates (PFCAs) in the environment. A fluoroacrylate polymer product test substance was studied in four aerobic soils over two years to assess whether the fluorotelomer alcohol (FTOH) side chains covalently bonded to the polymer backbone may be transformed to form PFCAs. The test substance itself was not directly measured; instead, nine analytes were determined to evaluate biodegradation. Terminal biotransformation products measured included perfluorooctanoate (PFO), perfluorononanoate (PFN), perfluorodecanoate (PFD), perfluoroundecanoate (PFU), and pentadecafluorodecanoate (7-3 acid). The molar concentration of 8-2 fluorotelomer alcohol (8-2 FTOH) in the test substance, fluoroacrylate polymer and residual unreacted raw materials and impurities ("residuals") were compared with the molar concentrations of the terminal biotransformation products for mass balance and kinetic assessments. Over the two year time frame of the experimental study, the fluoroacrylate polymer showed a slight extent of potential biodegradation under the experimental conditions of the study. A biodegradation half-life of 1200-1700 years was calculated for the fluoroacrylate polymer based on the rate of formation of PFO in aerobic soils. When the degradation rates of the fluoroacrylate polymer and residuals were applied to estimated total historic fluoroacrylate polymer production, use and disposal, the biodegradation of fluoroacrylate polymer and residuals is calculated to contribute less than 5 tonnes of PFO per year globally to PFCAs present in the environment.
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Affiliation(s)
- Mark H Russell
- E. I. duPont de Nemours and Co., Inc., Wilmington, Delaware, USA.
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39
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Powley CR, George SW, Russell MH, Hoke RA, Buck RC. Polyfluorinated chemicals in a spatially and temporally integrated food web in the Western Arctic. Chemosphere 2008; 70:664-72. [PMID: 17698166 DOI: 10.1016/j.chemosphere.2007.06.067] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 06/21/2007] [Accepted: 06/25/2007] [Indexed: 05/03/2023]
Abstract
This study reports on an investigation of the presence of polyfluorinated chemicals in a spatially and temporally integrated set of biological samples representing an Arctic food web. Zooplankton, Arctic cod, and seal tissues from the western Canadian Arctic were analyzed for perfluoroalkyl sulfonates [PFAS], perfluorocarboxylates [PFCAs], and other polyfluorinated acids. Perfluorooctane sulfonate [PFOS] was found in all samples [0.20-34 ng/g] and in the highest concentrations. PFCAs from nine to 12 carbons were quantified in most of the samples [0.28-6.9 ng/g]. PFCAs with carbon chain lengths of eight or less were not detected. Likewise, 8-2 fluorotelomer acid [8-2 FTA] and 8-2 fluorotelomer unsaturated acid [8-2 FTUA], products of fluorotelomer environmental transformation, were not detected. 2H,2H,3H,3H, heptadecafluoro decanoic acid [7-3 Acid], an additional metabolite from fluorotelomer biological transformation, was detected only in seal liver tissue [0.5-2.5 ng/g]. The ratios of branched to linear PFOS isomers in fish and seal tissue were not similar and did not match that of technical PFOS as manufactured. No branched PFCA isomers were detected in any samples. It is concluded that differing pharmacokinetics complicate the use of branched to linear ratios of PFCAs in attributing their presence to a specific manufacturing process. A statistical analysis of the data revealed significant correlations between PFOS and the PFCAs detected as well as among the PFCAs themselves. The 7-3 Acid was not correlated with either PFCAs or PFAS, which suggests that it may have a different exposure pathway.
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Affiliation(s)
- Charles R Powley
- E.I. DuPont de Nemours & Co., Inc., P.O. Box 50, Newark, DE 19714-0050, USA.
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40
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Nabb DL, Szostek B, Himmelstein MW, Mawn MP, Gargas ML, Sweeney LM, Stadler JC, Buck RC, Fasano WJ. In Vitro Metabolism of 8-2 Fluorotelomer Alcohol: Interspecies Comparisons and Metabolic Pathway Refinement. Toxicol Sci 2007; 100:333-44. [PMID: 17785680 DOI: 10.1093/toxsci/kfm230] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The detection of perfluorinated organic compounds in the environment has generated interest in their biological fate. 8-2 Fluorotelomer alcohol (8-2 FTOH, C(7)F(15)CF(2)CH(2)CH(2)OH), a raw material used in the manufacture of fluorotelomer-based products, has been identified in the environment and has been implicated as a potential source for perfluorooctanoic acid (PFOA) in the environment. In this study, the in vitro metabolism of [3-(14)C] 8-2 FTOH and selected acid metabolites by rat, mouse, trout, and human hepatocytes and by rat, mouse, and human liver microsomes and cytosol were investigated. Clearance rates of 8-2 FTOH in hepatocytes indicated rat > mouse > human >/= trout. A number of metabolites not previously reported were identified, adding further understanding to the pathway for 8-2 FTOH metabolism. Neither perfluorooctanoate nor perfluorononanoate was detected from incubations with human microsomes. To further elucidate the steps in the metabolic pathway, hepatocytes were incubated with 8-2 fluorotelomer acid, 8-2 fluorotelomer unsaturated acid, 7-3 acid, 7-3 unsaturated acid, and 7-2 secondary fluorotelomer alcohol. Shorter chain perfluorinated acids were only observed in hepatocyte and microsome incubations of the 8-2 acids but not from the 7-3 acids. Overall, the results indicate that 8-2 FTOH is extensively metabolized in rats and mice and to a lesser extent in humans and trout. Metabolism of 8-2 FTOH to perfluorinated acids was extremely small and likely mediated by enzymes in the microsomal fraction. These results suggest that human exposure to 8-2 FTOH is not expected to be a significant source of PFOA or any other perfluorocarboxylic acids.
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Affiliation(s)
- Diane L Nabb
- DuPont Haskell Laboratory for Health and Environmental Sciences, Newark, DE 19714, USA.
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41
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Yarwood G, Kemball-Cook S, Keinath M, Waterland RL, Korzeniowski SH, Buck RC, Russell MH, Washburn ST. High-resolution atmospheric modeling of fluorotelomer alcohols and perfluorocarboxylic acids in the North American troposphere. Environ Sci Technol 2007; 41:5756-62. [PMID: 17874783 DOI: 10.1021/es0708971] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A high spatial and temporal resolution atmospheric model is used to evaluate the potential contribution of fluorotelomer alcohol (FTOH) and perfluorocarboxylate (PFCA) emissions associated with the manufacture, use, and disposal of DuPont fluorotelomer-based products in North America to air concentrations of FTOH, perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) in North America and the Canadian Arctic. A bottom-up emission inventory for PFCAs and FTOHs was developed from sales and product composition data. A detailed FTOH atmospheric degradation mechanism was developed to simulate FTOH degradation to PFCAs and model atmospheric transport of PFCAs and FTOHs. Modeled PFCA yields from FTOH degradation agree with experimental smog-chamber results supporting the degradation mechanism used. Estimated PFCA and FTOH air concentrations and PFCA deposition fluxes are compared to monitoring data and previous global modeling. Predicted FTOH air concentrations are generally in agreement with available monitoring data. Overall emissions from the global fluorotelomer industry are estimated to contribute approximately 1-2% of the PFCAs in North American rainfall, consistent with previous global emissions estimates. Emission calculations and modeling results indicate that atmospheric inputs of PFCAs in North America from fluorotelomer-based products will decline by an order of magnitude in the near future as a result of current industry commitments to reduce manufacturing emissions and lower the residual fluorotelomer alcohol raw material and trace PFCA product content.
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Affiliation(s)
- Greg Yarwood
- ENVIRON International Corporation, Golden Gate Plaza, 101 Rowland Way, Novato, California 94945, USA
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42
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Nakayama T, Takahashi K, Matsumi Y, Toft A, Andersen MPS, Nielsen OJ, Waterland RL, Buck RC, Hurley MD, Wallington TJ. Atmospheric chemistry of CF3CH=CH2 and C4F9CH=CH2: products of the gas-phase reactions with Cl atoms and OH radicals. J Phys Chem A 2007; 111:909-15. [PMID: 17266232 DOI: 10.1021/jp066736l] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
FTIR-smog chamber techniques were used to study the products of the Cl atom and OH radical initiated oxidation of CF3CH=CH2 in 700 Torr of N2/O2, diluent at 296 K. The Cl atom initiated oxidation of CF3CH=CH2 in 700 Torr of air in the absence of NOx gives CF3C(O)CH2Cl and CF3CHO in yields of 70+/-5% and 6.2+/-0.5%, respectively. Reaction with Cl atoms proceeds via addition to the >C=C< double bond (74+/-4% to the terminal and 26+/-4% to the central carbon atom) and leads to the formation of CF3CH(O)CH2Cl and CF3CHClCH2O radicals. Reaction with O2 and decomposition via C-C bond scission are competing loss mechanisms for CF3CH(O)CH2Cl radicals, kO2/kdiss=(3.8+/-1.8)x10(-18) cm3 molecule-1. The atmospheric fate of CF3CHClCH2O radicals is reaction with O2 to give CF3CHClCHO. The OH radical initiated oxidation of CxF2x+1CH=CH2 (x=1 and 4) in 700 Torr of air in the presence of NOx gives CxF2x+1CHO in a yield of 88+/-9%. Reaction with OH radicals proceeds via addition to the >C=C< double bond leading to the formation of CxF2x+1C(O)HCH2OH and CxF2x+1CHOHCH2O radicals. Decomposition via C-C bond scission is the sole fate of CxF2x+1CH(O)CH2OH and CxF2x+1CH(OH)CH2O radicals. As part of this work a rate constant of k(Cl+CF3C(O)CH2Cl)=(5.63+/-0.66)x10(-14) cm3 molecule-1 s-1 was determined. The results are discussed with respect to previous literature data and the possibility that the atmospheric oxidation of CxF2x+1CH=CH2 contributes to the observed burden of perfluorocarboxylic acids, CxF2x+1COOH, in remote locations.
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Affiliation(s)
- T Nakayama
- Solar-Terrestrial Environment Laboratory and Graduate School of Science, Nagoya University, Honohara 3-13, Toyokawa, Aichi, 442-8507 Japan
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43
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Armitage J, Cousins IT, Buck RC, Prevedouros K, Russell MH, MacLeod M, Korzeniowski SH. Modeling global-scale fate and transport of perfluorooctanoate emitted from direct sources. Environ Sci Technol 2006; 40:6969-75. [PMID: 17154003 DOI: 10.1021/es0614870] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The long-term (1950-2050) global fate of perfluorooctanoate (PFO) is investigated using the global distribution model, GloboPOP. The model is used to test the hypotheses that direct PFO emissions can account for levels observed in the global oceans and that ocean water transport to the Arctic is an important global distribution pathway. The model emission scenarios are derived from historical and projected PFO emissions solely from direct sources. Modeled ocean water concentrations compare favorably to observed PFO concentrations in the world's oceans and thus ocean inventories can be accounted for by direct sources. The model results support the hypothesis that long-range ocean transport of PFO to the Arctic is important and estimate a net PFO influx of approximately 8-23 tons per year flowing into the model's Northern Polar zone in 2005, an amount at least 1 order of magnitude greater than estimated PFO flux to the Arctic from potential indirect sources such as atmospheric transport and degradation of fluorotelomer alcohols. Modeled doubling times of ocean water concentrations in the Arctic between 1975 and 2005 of approximately 7.5-10 years are in good agreement with doubling times of PFO in Arctic biota estimated from monitoring data. The model is further applied to predict future trends in PFO contamination levels using forecasted (2005-2050) direct emissions, including substantial reductions committed to by industry. Modeled ocean water concentrations in zones near to sources decline markedly after 2005, whereas modeled concentrations in the Arctic are predicted to continue to increase until approximately 2030 and show no significant decrease for the remaining 20 years of the model simulation. Since water is the primary exposure medium for Arctic biota, these model results suggest that concentrations in Arctic biota may continue to rise long after direct emissions have been substantially reduced or eliminated.
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Affiliation(s)
- James Armitage
- Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden
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44
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Chiappero MS, Malanca FE, Argüello GA, Wooldridge ST, Hurley MD, Ball JC, Wallington TJ, Waterland RL, Buck RC. Atmospheric Chemistry of Perfluoroaldehydes (CxF2x+1CHO) and Fluorotelomer Aldehydes (CxF2x+1CH2CHO): Quantification of the Important Role of Photolysis. J Phys Chem A 2006; 110:11944-53. [PMID: 17064182 DOI: 10.1021/jp064262k] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The UV absorption spectra of CF(3)CHO, C(2)F(5)CHO, C(3)F(7)CHO, C(4)F(9)CHO, CF(3)CH(2)CHO, and C(6)F(13)CH(2)CHO were recorded over the range 225-400 nm at 249-297 K. C(x)F(2)(x)(+1)CHO and C(x)F(2)(x)(+1)CH(2)CHO have broad absorption features centered at 300-310 and 290-300 nm, respectively. The strength of the absorption increases with the size of the C(x)F(2)(x)(+1) group. There was no discernible (<5%) effect of temperature on the UV spectra. Quantum yields for photolysis at 254 and 308 nm were measured. Quantum yields at 254 nm were 0.79 +/- 0.09 (CF(3)CHO), 0.81 +/- 0.09 (C(2)F(5)CHO), 0.63 +/- 0.09 (C(3)F(7)CHO), 0.60 +/- 0.09 (C(4)F(9)CHO), 0.74 +/- 0.08 (CF(3)CH(2)CHO), and 0.55 +/- 0.09 (C(6)F(13)CH(2)CHO). Quantum yields at 308 nm were 0.17 +/- 0.03 (CF(3)CHO), 0.08 +/- 0.02 (C(4)F(9)CHO), and 0.04 +/- 0.01 (CF(3)CH(2)CHO). The quantum yields decrease with increasing size of the C(x)F(2)(x)(+1) group and with increasing wavelength of the photolysis light. The photolysis quantum yield at 308 nm for CF(3)CHO measured here is a factor of at least 8 greater than that reported previously. Photolysis is probably the dominant atmospheric fate of C(x)F(2)(x)(+1)CHO (x = 1-4) and is an important fate of C(x)F(2)(x)(+1)CH(2)CHO (x = 1 and 6). These results have important ramifications concerning the yield of perfluorocarboxylic acids in the atmospheric oxidation of fluorotelomer alcohols.
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Affiliation(s)
- Malisa S Chiappero
- INFIQC, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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45
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Fasano WJ, Carpenter SC, Gannon SA, Snow TA, Stadler JC, Kennedy GL, Buck RC, Korzeniowski SH, Hinderliter PM, Kemper RA. Absorption, Distribution, Metabolism, and Elimination of 8-2 Fluorotelomer Alcohol in the Rat. Toxicol Sci 2006; 91:341-55. [PMID: 16543293 DOI: 10.1093/toxsci/kfj160] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The absorption, distribution, metabolism, and elimination of [3-14C] 8-2 fluorotelomer alcohol (8-2 FTOH, C7F1514CF2CH2CH2OH) following a single oral dose at 5 and 125 mg/kg in male and female rats have been determined. Following oral dosing, the maximum concentration of 8-2 FTOH in plasma occurred by 1 h postdose and cleared rapidly with a half-life of less than 5 h. The internal dose to 8-2 FTOH, as measured by area under the concentration-time curve to infinity, was similar for male and female rats and was observed to increase in a dose-dependent fashion. The majority of the 14C 8-2 FTOH (> 70%) was excreted in feces, and 37-55% was identified as parent. Less than 4% of the administered dose was excreted in urine, which contained low concentrations of perfluorooctanoate (approximately 1% of total 14C). Metabolites identified in bile were principally composed of glucuronide and glutathione conjugates, and perfluorohexanoate was identified in excreta and plasma, demonstrating the metabolism of the parent FTOH by sequential removal of multiple CF2 groups. At 7 days postdose, 4-7% of the administered radioactivity was present in tissues, and for the majority, 14C concentrations were greater than whole blood with the highest concentration in fat, liver, thyroid, and adrenals. Distribution and excretion of a single 125-mg/kg [3-14C] 8-2 FTOH dermal dose following a 6-h exposure in rats was also determined. The majority of the dermal dose either volatilized from the skin (37%) or was removed by washing (29%). Following a 6-h dermal exposure and a 7-day collection period, excretion of total radioactivity via urine (< 0.1%) and feces (< 0.2%) was minor, and radioactivity concentrations in most tissues were below the limit of detection. Systemic availability of 8-2 FTOH following dermal exposure was negligible.
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Affiliation(s)
- William J Fasano
- DuPont Haskell Laboratory for Health and Environmental Sciences, Newark, Delaware 19714, USA.
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46
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Cobranchi DP, Botelho M, Buxton LW, Buck RC, Kaiser MA. Vapor pressure determinations of 8-2 fluorortelomer alcohol and 1-H perfluorooctane by capillary gas chromatography. J Chromatogr A 2006; 1108:248-51. [PMID: 16443234 DOI: 10.1016/j.chroma.2006.01.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 01/09/2006] [Indexed: 11/18/2022]
Abstract
Two distinctly different capillary gas chromatographic methods were used to determine the vapor pressure of 8-2 fluorotelomer alcohol (8-2 FTOH) and 1-H perfluoroheptane at several temperatures. For measurements employing the relative retention-time method, a short polymethylsiloxane column was used from 25 to 65 degrees C. For the 8-2 FTOH, hydrocarbon alcohols and perfluoroalcohols were used as reference standards. For 1-H perfluoroheptane, hydrocarbons were used as reference standards. Vapor pressure estimates could differ by as much as an order of magnitude compared to published results determined by other (nonchromatographic) methods. This variance may be a function of solvent-solute interactions within the gas chromatographic column and the infinite dilution assumption, both used in the relative retention method. For comparison, data were also gathered using headspace gas chromatography (GC) with atomic emission detection (AED). The results from this novel GC/AED method were consistent with prior nonchromatographic results. A discussion of why headspace is the preferred technique for the determination of vapor pressure for fluorinated compounds is presented.
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Affiliation(s)
- Daryl P Cobranchi
- DuPont Corporate Center for Analytical Sciences, PO Box 80402, Wilmington, DE 19880-0402, USA
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47
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Larsen BS, Stchur P, Szostek B, Bachmura SF, Rowand RC, Prickett KB, Korzeniowski SH, Buck RC. Method development for the determination of residual fluorotelomer raw materials and perflurooctanoate in fluorotelomer-based products by gas chromatography and liquid chromatography mass spectrometry. J Chromatogr A 2006; 1110:117-24. [PMID: 16473361 DOI: 10.1016/j.chroma.2006.01.086] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 01/16/2006] [Accepted: 01/19/2006] [Indexed: 11/24/2022]
Abstract
The methodology for the determination of perfluorooctanoate (C(7)F(15)COO-, PFO), fluorotelomer alcohols (FTOHs: 6-2, 8-2, and 10-2), perfluorooctyl iodide (PFOI), and 8-2-8 fluorotelomer alcohol ester in complex fluorotelomer-based commercial products has been demonstrated and validated. Sample preparation procedures allowing determination of residual levels of these compounds were developed. The analytes were detected either by LC/MS/MS (PFO), LC/MS (FTOHs), or GC/MS (PFOI, 8-2-8 ester). The methods were validated by investigating the recoveries of analytes spiked at multiple levels to authentic sample matrices. The recoveries generally were between 70 and 130%. The limits of detection were in sub-microg/g range and the limits of quantitation were in the mug/g range. The methods were applied to fluorotelomer-based raw materials and fluorotelomer-based surfactants and polymeric products and represent methods useful for the determination of higher carbon chain length homologs as well.
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Affiliation(s)
- Barbara S Larsen
- DuPont Corporate Center for Analytical Sciences, Central Research and Development, Experimental Station, Wilmington, DE 19880, USA.
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48
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Szostek B, Prickett KB, Buck RC. Determination of fluorotelomer alcohols by liquid chromatography/tandem mass spectrometry in water. Rapid Commun Mass Spectrom 2006; 20:2837-44. [PMID: 16941535 DOI: 10.1002/rcm.2667] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Fluorotelomer alcohols (FTOHs) are important polyfluorinated raw materials that belong to the general category of perfluoroalkyl substances (PFAS). PFAS, including perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates, have recently attracted considerable attention because they are persistent and found globally in the environment. FTOHs are precursors that may degrade in the environment to PFCAs. The development of analytical methods for determination FTOHs in environmental samples is necessary to determine the environmental presence of FTOHs. This work presents the development and validation of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of FTOHs (6-2, 8-2, 10-2) in aqueous samples. Chromatographic conditions were optimized in order to obtain focused FTOH chromatographic peaks. The mobile phase and mass spectrometric conditions were optimized to enable formation of deprotonated FTOH molecules in the negative ion electrospray mode. Two extraction methods were investigated using acetonitrile and methyl tert-butyl ether (MTBE). These methods were validated for a range of environmental water samples fortified with FTOHs at three different levels. Both extraction methods resulted in recoveries from 70 to 120%. Detection limits of FTOHs were estimated to be approximately 0.09 ng/mL for LC/MS/MS detection. An LC/MS method was also developed for FTOH determination with an estimated 1.2 ng/mL limit of detection. Various sample storage scenarios were investigated. It was determined that the aqueous samples of FTOHs are best preserved by storing them frozen in sealed vials with aluminum foil lined septa.
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Affiliation(s)
- Bogdan Szostek
- DuPont Haskell Laboratory for Health and Environmental Sciences, 1090 Elkton Rd., Newark, DE 19714-0050, USA.
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49
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Abstract
This review describes the sources, fate, and transport of perfluorocarboxylates (PFCAs) in the environment, with a specific focus on perfluorooctanoate (PFO). The global historical industry-wide emissions of total PFCAs from direct (manufacture, use, consumer products) and indirect (PFCA impurities and/or precursors) sources were estimated to be 3200-7300 tonnes. It was estimated that the majority (approximately 80%) of PFCAs have been released to the environment from fluoropolymer manufacture and use. Although indirect sources were estimated to be much less importantthan direct sources, there were larger uncertainties associated with the calculations for indirect sources. The physical-chemical properties of PFO (negligible vapor pressure, high solubility in water, and moderate sorption to solids) suggested that PFO would accumulate in surface waters. Estimated mass inventories of PFO in various environmental compartments confirmed that surface waters, especially oceans, contain the majority of PFO. The only environmental sinks for PFO were identified to be sediment burial and transport to the deep oceans, implying a long environmental residence time. Transport pathways for PFCAs in the environment were reviewed, and it was concluded that, in addition to atmospheric transport/degradation of precursors, atmospheric and ocean water transport of the PFCAs themselves could significantly contribute to their long-range transport. It was estimated that 2-12 tonnes/ year of PFO are transported to the Artic by oceanic transport, which is greater than the amount estimated to result from atmospheric transport/degradation of precursors.
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Affiliation(s)
- Konstantinos Prevedouros
- Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden
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50
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Yamada T, Taylor PH, Buck RC, Kaiser MA, Giraud RJ. Thermal degradation of fluorotelomer treated articles and related materials. Chemosphere 2005; 61:974-84. [PMID: 16257319 DOI: 10.1016/j.chemosphere.2005.03.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 03/09/2005] [Accepted: 03/11/2005] [Indexed: 05/05/2023]
Abstract
This study reports the first known studies to investigate the thermal degradation of a polyester/cellulose fabric substrate ("article") treated with a fluorotelomer-based acrylic polymer under laboratory conditions conservatively representing typical combustion conditions of time, temperature, and excess air level in a municipal incinerator, with an average temperature of 1000 degrees C or greater over approximately 2s residence time. The results demonstrate that the polyester/cellulose fabric treated with a fluorotelomer-based acrylic polymer is destroyed and no detectable amount of perfluorooctanoic acid (PFOA) is formed under typical municipal incineration conditions. Therefore, textiles and paper treated with such a fluorotelomer-based acrylic polymer disposed of in municipal waste and incinerated are expected to be destroyed and not be a significant source of PFOA in the environment.
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Affiliation(s)
- Takahiro Yamada
- Environmental Engineering Group, University of Dayton Research Institute, 300 College Park, Dayton, OH 45469-0114, USA
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