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Jonathan W. Martin - One of the best experts on this subject based on the ideXlab platform.

  • formation of c7f15cooh pfoa and other perfluorocarboxylic acids during the atmospheric oxidation of 8 2 Fluorotelomer alcohol
    Environmental Science & Technology, 2006
    Co-Authors: M D Hurley, David A. Ellis, Jonathan W. Martin, Donald J Wuebbles, Sanford Sillman, Joyce E Penner, O J Nielsen, M Sulbaek P Andersen
    Abstract:

    Calculations using a three-dimensional global atmospheric chemistry model (IMPACT) indicate that n-C8F17CH2CH2OH (widely used in industrial and consumer products) degrades in the atmosphere to give perfluorooctanoic acid (PFOA) and other perfluorocarboxylic acids (PFCAs). PFOA is persistent, bioaccumulative, and potentially toxic. Molar yields of PFOA depend on location and season, are in the range of 1−10%, and are of the correct order of magnitude to explain the observed levels in Arctic fauna. Fluorotelomer alcohols such as n-C8F17CH2CH2OH appear to be a significant global source of persistent bioaccumulative perfluorocarboxylic acid pollution. This is the first modeling study of the atmospheric chemistry of a Fluorotelomer alcohol.

  • Metabolic products and pathways of Fluorotelomer alcohols in isolated rat hepatocytes.
    Chemico-biological interactions, 2005
    Co-Authors: Jonathan W. Martin, Peter J. O'brien
    Abstract:

    Fluorotelomer alcohols (FTOHs; CF(3)(CF(2))(x)C(2)H(4)OH; where x=3, 5, 7, 9) are a novel class of polyfluorinated contaminants, recently detected in the North American atmosphere, that are possible precursors to the series of perfluoroalkyl carboxylates (PFCAs) in human blood. An in vivo rat study validated earlier independent work that poly- and per-fluoroalkyl carboxylates were metabolites of FTOHs, but our detection of several novel metabolites prompted us to examine their pathways in greater detail using isolated rat hepatocytes. Using 8:2 FTOH (i.e. where x=7) as a model compound, the metabolic products formed by isolated rat hepatocytes were identified, and three synthesized intermediates were incubated separately to elucidate the metabolic pathways. For 8:2 FTOH, a major fate was direct conjugation to form the O-glucuronide and O-sulfate. Using 2,4-dinitrophenylhydrazine (DNPH) trapping, the immediate oxidation product of 8:2 FTOH was identified as 8:2 Fluorotelomer aldehyde (8:2 FTAL; CF(3)(CF(2))(7)CH(2)C(H)O). 8:2 FTAL was transient and eliminated HF non-enzymatically to yield 8:2 Fluorotelomer alpha,beta-unsaturated aldehyde (8:2 FTUAL; CF(3)(CF(2))(6)CFCHC(H)O) which was also short-lived and reacted GSH and perhaps other endogenous nucleophiles. Four polyfluorinated acid intermediates were also detected, including 8:2 Fluorotelomer carboxylate (8:2 FTCA; CF(3)(CF(2))(7)CH(2)C(O)O(-)), 8:2 Fluorotelomer alpha,beta-unsaturated carboxylate (8:2 FTUCA; CF(3)(CF(2))(6)CFCHC(O)O(-)), tetrahydroperfluorodecanoate (CF(3)(CF(2))(6)(CH(2))(2)CO(2)(-)), and dihydroperfluorodecenoate (CF(3)(CF(2))(6)CHCHCO(2)(-)). The pathways leading to 8:2 FTCA and FTUCA involve oxidation of 8:2 FTAL, however, the pathways leading to the latter two polyfluorinated acids remain inconclusive. The fate of the unsaturated metabolites, 8:2 FTUAL and FTUCA, included conjugation with GSH and dehydrofluorination to yield alpha,beta-unsaturated GSH conjugates, and GS-8:2 FTUAL which was subsequently reduced to the corresponding alcohol. Perfluorooctanoate (PFOA) and minor amounts of perfluorononanoate (PFNA) were confirmed as metabolites of 8:2 FTOH, and the respective roles of beta- and alpha-oxidation mechanisms are discussed. The analogous acids, aldehydes, and conjugated metabolites of 4:2, 6:2, and 10:2 FTOH (i.e. where x=3, 5, and 9, respectively) were also detected, and metabolite profiles among FTOHs generally differed only in the length of their perfluoroalkyl chains. Preincubation with aminobenzotriazole, but not pyrazole, inhibited the formation of metabolites from all FTOHs, suggesting that their oxidation was catalyzed by P450, not alcohol dehydrogenase.

  • atmospheric chemistry of 4 2 Fluorotelomer alcohol cf3 cf2 3ch2ch2oh products and mechanism of cl atom initiated oxidation
    Journal of Physical Chemistry A, 2004
    Co-Authors: Michael D. Hurley, James C. Ball, T. J. Wallington, David A. Ellis, M Sulbaek P Andersen, Jonathan W. Martin
    Abstract:

    Smog chamber/FTIR techniques were used to study the products and mechanism of the Cl atom initiated oxidation of 4:2 Fluorotelomer alcohol (CF3(CF2)3CH2CH2OH) in 700 Torr of N2/O2 diluent at 296 K. CF3(CF2)3CH2CHO is the sole primary oxidation product. CF3(CF2)3CHO, CF3(CF2)3CH2COOH, and CF3(CF2)3CH2C(O)OOH are secondary oxidation products. Further irradiation results in the formation of CF3(CF2)3COOH, COF2, and CF3OH. CF3(CF2)3CHO, CF3(CF2)3CH2COOH, and CF3(CF2)3CH2C(O)OOH are formed from CF3(CF2)3CH2CHO oxidation in yields of 46%, 27%, and ≤27%, respectively. Using relative rate techniques, a value of k(Cl + CF3(CF2)3CH2CHO) = (1.84 ± 0.30) × 10-11 cm3 molecule-1 s-1 was determined. The yield of the perfluorinated acid, CF3(CF2)3COOH, from the 4:2 Fluorotelomer alcohol increased with the diluent gas oxygen concentration. For the experimental conditions used herein and employing >98% consumption of 4:2 Fluorotelomer alcohol, the molar yields of CF3(CF2)3COOH were <0.011, 0.031, 0.042, and 0.056 in experi...

  • Atmospheric Chemistry of 4:2 Fluorotelomer Alcohol (CF3(CF2)3CH2CH2OH): Products and Mechanism of Cl Atom Initiated Oxidation
    The Journal of Physical Chemistry A, 2004
    Co-Authors: Michael D. Hurley, James C. Ball, David A. Ellis, M. P. Sulbaek Andersen, Jonathan W. Martin
    Abstract:

    Smog chamber/FTIR techniques were used to study the products and mechanism of the Cl atom initiated oxidation of 4:2 Fluorotelomer alcohol (CF3(CF2)3CH2CH2OH) in 700 Torr of N2/O2 diluent at 296 K....

  • Atmospheric Lifetime of Fluorotelomer Alcohols
    Environmental science & technology, 2003
    Co-Authors: David A. Ellis, Scott A. Mabury, Michael D. Hurley, Jonathan W. Martin, M. P. Sulbaek Andersen
    Abstract:

    Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with a series of Fluorotelomer alcohols, F(CF2CF2)nCH2CH2OH (n = 2, 3, 4), in 700 Torr of N2 or air, diluent at 296 ± 2K. The length of the F(CF2CF2)n- group had no discernible impact on the reactivity of the molecule. For n = 2, 3, or 4, k(Cl + F(CF2CF2)nCH2CH2OH) = (1.61 ± 0.49) × 10-11 and k(OH + F(CF2CF2)nCH2CH2OH) = (1.07 ± 0.22) × 10-12 cm3 molecule-1 s-1. Consideration of the likely rates of other possible atmospheric loss mechanisms leads to the conclusion that the atmospheric lifetime of F(CF2CF2)nCH2CH2OH (n ≥ 2) is determined by reaction with OH radicals and is approximately 20 d.

Michael D. Hurley - One of the best experts on this subject based on the ideXlab platform.

  • Atmospheric chemistry of 4:2 Fluorotelomer iodide (n-C4F9CH2CH2I): kinetics and products of photolysis and reaction with OH radicals and Cl atoms.
    The journal of physical chemistry. A, 2008
    Co-Authors: Cora J. Young, Michael D. Hurley
    Abstract:

    Relative rate techniques were used to study the title reactions and determine rate constants of k(Cl + C4F9CH2CH2I) = (1.25 ± 0.15) × 10−12 and k(OH + C4F9CH2CH2I) = (1.2 ± 0.6) × 10−12 cm3 molecule−1 s−1 in 700 Torr total pressure at 295 K. The Fluorotelomer aldehyde (C4F9CH2CHO), perfluorinated aldehyde (C4F9CHO), Fluorotelomer acid (C4F9CH2C(O)OH), Fluorotelomer peracid (C4F9CH2C(O)OOH), and several perfluorocarboxylic acids were detected by in situ FTIR spectroscopy and offline analysis as products of the chlorine atom initiated oxidation of C4F9CH2CH2I in air. The UV−visible spectra of C4F9CH2CH2I and C2H5Cl were recorded over the range of 200−400 nm. Photolysis of C4F9CH2CH2I gives C4F9CH2CHO as the major observed product. By assumption of a photolysis quantum yield of unity, it was calculated that the atmospheric lifetime of C4F9CH2CH2I is determined by photolysis and is a few days. A mechanism for the atmospheric oxidation of Fluorotelomer iodides, (CxF2x+1CH2CH2I, where x = 2, 4, 6,...) is propos...

  • atmospheric chemistry of 4 2 Fluorotelomer alcohol cf3 cf2 3ch2ch2oh products and mechanism of cl atom initiated oxidation
    Journal of Physical Chemistry A, 2004
    Co-Authors: Michael D. Hurley, James C. Ball, T. J. Wallington, David A. Ellis, M Sulbaek P Andersen, Jonathan W. Martin
    Abstract:

    Smog chamber/FTIR techniques were used to study the products and mechanism of the Cl atom initiated oxidation of 4:2 Fluorotelomer alcohol (CF3(CF2)3CH2CH2OH) in 700 Torr of N2/O2 diluent at 296 K. CF3(CF2)3CH2CHO is the sole primary oxidation product. CF3(CF2)3CHO, CF3(CF2)3CH2COOH, and CF3(CF2)3CH2C(O)OOH are secondary oxidation products. Further irradiation results in the formation of CF3(CF2)3COOH, COF2, and CF3OH. CF3(CF2)3CHO, CF3(CF2)3CH2COOH, and CF3(CF2)3CH2C(O)OOH are formed from CF3(CF2)3CH2CHO oxidation in yields of 46%, 27%, and ≤27%, respectively. Using relative rate techniques, a value of k(Cl + CF3(CF2)3CH2CHO) = (1.84 ± 0.30) × 10-11 cm3 molecule-1 s-1 was determined. The yield of the perfluorinated acid, CF3(CF2)3COOH, from the 4:2 Fluorotelomer alcohol increased with the diluent gas oxygen concentration. For the experimental conditions used herein and employing >98% consumption of 4:2 Fluorotelomer alcohol, the molar yields of CF3(CF2)3COOH were <0.011, 0.031, 0.042, and 0.056 in experi...

  • Atmospheric Chemistry of 4:2 Fluorotelomer Alcohol (CF3(CF2)3CH2CH2OH): Products and Mechanism of Cl Atom Initiated Oxidation
    The Journal of Physical Chemistry A, 2004
    Co-Authors: Michael D. Hurley, James C. Ball, David A. Ellis, M. P. Sulbaek Andersen, Jonathan W. Martin
    Abstract:

    Smog chamber/FTIR techniques were used to study the products and mechanism of the Cl atom initiated oxidation of 4:2 Fluorotelomer alcohol (CF3(CF2)3CH2CH2OH) in 700 Torr of N2/O2 diluent at 296 K....

  • Atmospheric Lifetime of Fluorotelomer Alcohols
    Environmental science & technology, 2003
    Co-Authors: David A. Ellis, Scott A. Mabury, Michael D. Hurley, Jonathan W. Martin, M. P. Sulbaek Andersen
    Abstract:

    Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with a series of Fluorotelomer alcohols, F(CF2CF2)nCH2CH2OH (n = 2, 3, 4), in 700 Torr of N2 or air, diluent at 296 ± 2K. The length of the F(CF2CF2)n- group had no discernible impact on the reactivity of the molecule. For n = 2, 3, or 4, k(Cl + F(CF2CF2)nCH2CH2OH) = (1.61 ± 0.49) × 10-11 and k(OH + F(CF2CF2)nCH2CH2OH) = (1.07 ± 0.22) × 10-12 cm3 molecule-1 s-1. Consideration of the likely rates of other possible atmospheric loss mechanisms leads to the conclusion that the atmospheric lifetime of F(CF2CF2)nCH2CH2OH (n ≥ 2) is determined by reaction with OH radicals and is approximately 20 d.

Derek C. G. Muir - One of the best experts on this subject based on the ideXlab platform.

  • biotransformation pathways of Fluorotelomer based polyfluoroalkyl substances a review
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Craig M. Butt, Derek C. G. Muir
    Abstract:

    The study reviews the current state of knowledge regarding the biotransformation of Fluorotelomer-based compounds, with a focus on compounds that ultimately degrade to form perfluoroalkyl carboxylates (PFCAs). Most metabolism studies have been performed with either microbial systems or rats and mice, and comparatively few studies have used fish models. Furthermore, biotransformation studies thus far have predominately used the 8:2 Fluorotelomer alcohol (FTOH) as the substrate. However, there have been an increasing number of studies investigating 6:2 FTOH biotransformation as a result of industry's transition to shorter-chain Fluorotelomer chemistry. Studies with the 8:2 FTOH metabolism universally show the formation of perfluorooctanoate (PFOA) and, to a smaller fraction, perfluorononanoate (PFNA) and lower-chain-length PFCAs. In general, the overall yield of PFOA is low, presumably because of the multiple branches in the biotransformation pathways, including conjugation reactions in animal systems. There have been a few studies of non-FTOH biotransformation, which include polyfluoroalkyl phosphates (PAPs), 8:2 Fluorotelomer acrylate (8:2 FTAC), and Fluorotelomer carboxylates (FTCAs, FTUCAs). The PAPs compounds and 8:2 FTAC were shown to be direct precursors to FTOHs and thus follow similar degradation pathways.

  • Dietary exposure of rainbow trout to 8:2 and 10:2 Fluorotelomer alcohols and perfluorooctanesulfonamide: Uptake, transformation and elimination
    Chemosphere, 2010
    Co-Authors: Sicco H. Brandsma, Keith R. Solomon, Marla Smithwick, Jeff Small, Jacob De Boer, Derek C. G. Muir
    Abstract:

    Abstract The bioaccumulation of perfluorooctanesulfonamide (PFOSA) and two Fluorotelomer alcohols (8:2 FTOH, 10:2 FTOH) by rainbow trout (Oncorhynchus mykiss) through dietary exposure, including depuration rates and metabolism was investigated. Concentrations in the spiked feed ranged from 10.9 μg g−1 wet weight (wet wt) for PFOSA and 6.7 μg g−1 wet wt for 8:2 FTOH to 5.0 μg g−1 wet wt for 10:2 FTOH. Trout was fed at 1.5% body weight per day for 30 d and depuration was followed for up to 30 d following previously published dietary exposure protocols. Perfluorooctanesulfonate (PFOS) was the major perfluoroalkylsulfonate (PFSA) detected in fish following dietary exposure to PFOSA. Half-lives of PFOS and PFOSA were 16.9 ± 2.5 and 6.0 ± 0.4 d, respectively. A biomagnification factor (BMF) of 0.023 was calculated for PFOSA which indicates that dietary exposure to PFOSA does not result in biomagnification in the rainbow trout. PFOS had a BMF of 0.08. The Fluorotelomer saturated acids (8:2 FTCA, 10:2 FTCA) and Fluorotelomer unsaturated acids (8:2 FTUCA, 10:2 FTUCA) were the major products detected in rainbow trout following dietary exposure to 8:2 FTOH and 10:2 FTOH, respectively. Half-lives were 3.7 ± 0.4, 2.1 ± 0.5, 3.3, and 1.3 d for 10:2 FTCA, 10:2 FTUCA, 8:2 FTCA, and 8:2 FTUCA, respectively. Small amounts of perfluorooctanoate (PFOA) and perfluorodecanoate (PFDA) were also detected in the FTOH exposed fish.

  • Biotransformation of the 8:2 Fluorotelomer acrylate in rainbow trout. 2. In vitro incubations with liver and stomach S9 fractions
    Environmental toxicology and chemistry, 2010
    Co-Authors: Craig M. Butt, Derek C. G. Muir
    Abstract:

    The biotransformation of the 8:2 Fluorotelomer acrylate (C(8) F(17) CH(2) CH(2) OC(O)CH = CH(2) , 8:2 Fluorotelomer-based acrylate [FTAc]) was quantitatively investigated in cytosolic (S9) fractions isolated from rainbow trout stomach and liver. The in vitro studies presented in this manuscript compliment the whole body 8:2 FTAc dietary exposure study, presented as a companion paper. The S9 fractions were prepared in our laboratory, using fish that had previously been used as control animals in our in vivo study. Before 8:2 FTAc incubations, general carboxylesterase activity was determined using paranitrophenyl acetate (PNPA) as the substrate with formation of paranitrophenol monitored using an ultraviolet-vis spectrometer. In the 8:2 FTAc incubations, the degradation of the parent compound and 8:2 Fluorotelomer alcohol (FTOH) formation was monitored by gas chromatography-mass spectrometry. Incubations were performed in triplicate, over a range of concentrations encompassing two orders of magnitude, and the initial rate of 8:2 FTOH or paranitrophenol formation was determined. Enzyme kinetic parameters were determined by plotting the initial rate versus concentration, using nonlinear regression analysis. The maximum initial velocities of the enzyme-catalyzed reaction (V(max)) in the PNPA incubations were 614 ± 18 nmol/min/mg and 147 ± 16 nmol/min/mg for the liver and stomach fractions, respectively. These values are much faster than other phase I and II metabolism reactions. The calculated intrinsic clearance rates (CL(int)) for the 8:2 FTAc incubations were 1.7 and 0.40 ml/min/mg protein, respectively. These results show that the esterase activity toward the 8:2 FTAc is only fourfold greater in the liver as compared with the stomach. These trends demonstrate the potential for considerable extrahepatic metabolism of the 8:2 FTAc before uptake into the internal tissues, ultimately limiting the overall bioaccumulation.

  • Biotransformation of the 8:2 Fluorotelomer acrylate in rainbow trout. 1. In vivo dietary exposure.
    Environmental toxicology and chemistry, 2010
    Co-Authors: Craig M. Butt, Derek C. G. Muir
    Abstract:

    The bioaccumulation and biotransformation of the 8:2 Fluorotelomer acrylate (C8F17CH2CH2OC(O)CH = CH2, 8:2 FTAc) was investigated in rainbow trout via dietary exposure. The 8:2 FTAc is a monomer used in the manufacture of fluorinated polymers and has been widely detected in the atmosphere. The parent 8:2 FTAc and suspected intermediate and terminal metabolites were monitored in liver, blood, kidney, bile, and feces during the 5-d uptake and 8-d elimination phases using gas chromatography-mass spectrometry (GC-MS)- and liquid chromatography-tandem mass spectrometry (LC-MS/MS)- based methods. Very low levels of the 8:2 FTAc were detected in the internal tissues and feces, suggesting that the 8:2 FTAc was rapidly biotransformed in the gut or liver. Similarly, low concentrations of the 8:2 Fluorotelomer alcohol (FTOH) were accumulated in the fish tissues. The 8:2 saturated Fluorotelomer carboxylate (FTCA) was formed in the highest concentration, reaching steady-state tissue concentrations of approximately 1,000 to 1,400 ng/g wet weight. The 8:2 FTUCA and 7:3 FTCA were also accumulated in high levels, at levels approximately 10-fold lower than the 8:2 FTCA. Both the 7:3 FTCA and perfluorooctanoate (PFOA) showed increasing levels throughout the uptake phase and into the initial stages of the elimination phase, indicating continued formation through precursors still present in the body. Perfluorononanoate (PFNA) was formed in low nanogram per gram wet weight levels. The intermediate and terminal metabolites were also detected in the bile and feces, indicating an important elimination pathway for these compounds. In addition, the 8:2 FTOH glucuronide conjugate was measured in relatively high concentrations in the bile and feces. The results of the current study demonstrated a scenario in which a biologically labile compound is biotransformed to terminal metabolites that are much more biologically persistent. Environ. Toxicol. Chem. 2010;29:2726–2735. © 2010 SETAC

  • perfluoroalkyl contaminants in the canadian arctic evidence of atmospheric transport and local contamination
    Environmental Science & Technology, 2007
    Co-Authors: Naomi L Stock, Derek C. G. Muir, Vasile I Furdui, Scott A. Mabury
    Abstract:

    Perfluorosulfonates (PFSAs) and perfluorocarboxylates (PFCAs) have been hypothesized to reach remote locations such as the Canadian Arctic either indirectly as volatile precursor chemicals that undergo atmospheric transport and subsequent degradation, or directly via oceanic and atmospheric transport of the PFSAs and PFCAs themselves. Water, sediment, and air samples were collected from three Arctic lakes (Amituk, Char, and Resolute) on Cornwallis Island, Nunavut, Canada. Samples were analyzed for PFSAs and PFCAs, precursor chemicals including the Fluorotelomer alcohols (FTOHs) and polyfluorinated sulfonamides (FSAs), and precursor degradation products such as the Fluorotelomer unsaturated carboxylates (FTUCAs). PFSAs and PFCAs were detected in water and sediment of all three Arctic lakes (concentrations ranged from nondetect to 69 ng/L and nondetect to 85 ng/g dry weight, respectively). FTOHs and FSAs were observed in air samples (mean concentrations ranged from 2.8 to 29 pg/m3), and confirm that volatil...

Robert C Buck - One of the best experts on this subject based on the ideXlab platform.

  • Aquatic hazard, bioaccumulation and screening risk assessment for 6:2 Fluorotelomer sulfonate.
    Chemosphere, 2015
    Co-Authors: Robert A. Hoke, Robert C Buck, Diane L. Nabb, Barbra D. Ferrell, Timothy W. Ryan, Terry L. Sloman, John W. Green, Robert T. Mingoia, Stephen H. Korzeniowski
    Abstract:

    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

  • Toxicological evaluation of 6:2 Fluorotelomer alcohol
    Toxicology, 2014
    Co-Authors: Tessa L. Serex, Robert C Buck, S. Satheesh Anand, Susan M. Munley, E. Maria Donner, Steven R. Frame, Scott E. Loveless
    Abstract:

    Abstract 6:2 Fluorotelomer alcohol (6:2 FTOH; CF 3 [CF 2 ] 5 [CH 2 ] 2 OH, 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 (LD 50  = 1750 mg/kg), and dermal (LD 50  > 5000 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 5 mg/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 LD 50 of 1750 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 5 mg/kg/day. For risk assessment purposes, the recommended point of departure is the more conservative study NOAEL of 5 mg/kg/day.

  • evaluation of pfo formation from the biodegradation of a Fluorotelomer based urethane polymer product in aerobic soils
    Polymer Degradation and Stability, 2010
    Co-Authors: Mark H Russell, Bogdan Szostek, William R. Berti, Ning Wang, Robert C Buck
    Abstract:

    Abstract This study is the first to evaluate the rate of formation of perfluorooctanoate (PFO) from the aerobic biodegradation of a Fluorotelomer-based urethane polymer and to use this information to assess the global environmental significance of this source. A Fluorotelomer-based urethane polymer product test substance was studied in four aerobic soils over two years to determine the rate at which the Fluorotelomer side-chains covalently bonded to the polymer backbone were cleaved and subsequently transformed to form the anions of perfluorocarboxylic acids including PFO. Over the two year duration of the experimental study, a polymer biodegradation half-life of 102 years (range: 28–241) was calculated for the urethane polymer based on regression analysis of the rate of PFO formation in four test soils. When this half-life was applied to the estimated total historic production, use and disposal of Fluorotelomer-based urethane polymer, the annual potential global generation of PFO was estimated to be less than one tonne per year.

  • investigation of the biodegradation potential of a fluoroacrylate polymer product in aerobic soils
    Environmental Science & Technology, 2008
    Co-Authors: Mark H Russell, Bogdan Szostek, William R. Berti, Robert C Buck
    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 y...

  • In vitro metabolism of 8-2 Fluorotelomer alcohol: interspecies comparisons and metabolic pathway refinement.
    Toxicological sciences : an official journal of the Society of Toxicology, 2007
    Co-Authors: Diane L. Nabb, Bogdan Szostek, Robert C Buck, Matthew W. Himmelstein, Michael P. Mawn, Michael L. Gargas, Lisa M. Sweeney, Judith C. Stadler, William J. Fasano
    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.

X. Dauchy - One of the best experts on this subject based on the ideXlab platform.

  • efficient electrochemical degradation of poly and perfluoroalkyl substances pfass from the effluents of an industrial wastewater treatment plant
    Chemical Engineering Journal, 2017
    Co-Authors: Beatriz Gomezruiz, Virginie Boiteux, Adeline Colin, X. Dauchy, Sonia Gomezlavin, Nazely Diban, Ane Urtiaga
    Abstract:

    Abstract This paper reports the electrochemical treatment of poly- and perfluoroalkyl substances (PFASs) in the effluent from an industrial wastewater treatment plant (WWTP). While most of the previous research focused on the electrochemical degradation of perfluorooctanoic acid and perfluorooctane sulfonate in model solutions, this work studies the simultaneous removal of 8 PFASs at environmentally relevant concentrations in real industrial emissions, which also contained organic matter and inorganic anions. The overall PFASs content in the WWTP effluent was 1652 µg/L, which emphasized the need to develop innovative technologies for the management of PFASs emissions. 6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) and 6:2 Fluorotelomer sulfonate (6:2 FTSA) were the major contributors (92% w/w) to the overall PFASs content, that also contained significant amounts of short-chain perfluorocarboxylic acids (PFCAs). Using a boron doped diamond (BDD) anode of 0.0070 m 2 , the effluent (2 L) was treated by applying a current density of 50 mA/cm 2 for 10 h, that resulted in 99.7% PFASs removal. The operation at lower current densities (5 and 10 mA/cm 2 ) evidenced the initial degradation of 6:2 Fluorotelomers into perfluoroheptanoic and perfluorohexanoic acids, that were later degraded into shorter chain PFCAs. The high TOC removal, >90%, and the fluoride release revealed that PFASs mineralization was effective. These results highlight the potential of the electrochemical technology for the treatment of PFASs contained in industrial wastewaters, which nowadays stands as the main source of this group of persistent pollutants into the environment.

  • concentrations and patterns of perfluoroalkyl and polyfluoroalkyl substances in a river and three drinking water treatment plants near and far from a major production source
    Science of The Total Environment, 2017
    Co-Authors: Virginie Boiteux, Adeline Colin, Jessica Hemard, Christophe Rosin, Cristina Bach, X. Dauchy, Veronique Sagres, Jean-françois Munoz
    Abstract:

    Abstract Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are emerging contaminants that have been detected in the environment, biota and humans. Drinking water is a route of exposure for populations using water contaminated by PFAS discharges. This research entailed measuring concentrations, mass flows and investigating the fate of dozens PFASs in a river receiving effluents from a fluorochemical manufacturing facility. To measure the total concentration of perfluoroalkyl carboxylic acid (PFCA) precursors, an oxidative conversion method was used. Several dozen samples were collected in the river (water and sediment), in drinking water resources and at different treatment steps on four sampling dates. One PFCA and three Fluorotelomers (FTs) were detected up to 62 km downstream from the manufacturing facility. 6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) was the predominant PFAS with a mass flow of 3830 g/day 5.2 km downstream from the facility. At all sampling points, PFAS concentrations in sediment were quite low ( Only nanofiltration was able to remove all the analyzed PFASs. In the treated water, total PFAS concentrations never exceeded 60 ng/L. The oxidative conversion method revealed the presence of unidentified PFCA precursors in the river. Therefore, 18 to 77% of the total PFCA content after oxidation consisted of unidentified chemical species. In the treated water, these percentages ranged from 0 to 29%, relatively and reassuringly low values.

  • Mass flows and fate of per- and polyfluoroalkyl substances (PFASs) in the wastewater treatment plant of a fluorochemical manufacturing facility
    Science of the Total Environment, 2017
    Co-Authors: X. Dauchy, Virginie Boiteux, Adeline Colin, Jessica Hemard, Christophe Rosin, Cristina Bach, Jean-françois Munoz
    Abstract:

    Although industrial sites producing perfluoroalkyl and polyfluoroalkyl substances (PFASs) may introduce these chemicals into the aquatic environment, they are rarely investigated. This study entailed measuring concentrations, mass flows and the fate of 51 PFASs in an industrial wastewater treatment plant receiving raw effluents from a fluorochemical manufacturing facility. Grab and 24-h composite samples were collected at various stages of wastewater treatment over four sampling campaigns. One perfluoroalkyl carboxylic acid (PFCA) and nine Fluorotelomers (FTs) were systematically detected in the facility's raw effluent. The overall PFCA mass flow ranged from 0.6 to 8.6 g/day and was negligible compared to the overall mass flow of FTs (from 647 to 2,892 g/day). PFCA mass flows increased drastically after secondary treatment (degradation of precursors) and decreased notably after the floatation tank (adsorption onto floatation sludge), but remained at relatively high levels in the final effluent (from 21 to 247 g/day). Similar patterns in mass flow were observed for the FTs, with mass loadings discharged into the river ranging from 1,623 to 6,963 g/day. Despite analyzing dozens of PFASs, adsorbable organic fluorine determination and oxidative conversion of PFCA precursors showed that a significant part of PFASs remained unidentified. Nevertheless, two overwhelmingly predominant PFASs—6:2 Fluorotelomer sulfonamide alkylbetaine (6:2 FTAB) and 6:2 Fluorotelomer sulfonamide propyl N,N dimethylamine (M4)—were detected and quantified for the first time in water samples, accounting for > 75% of the total PFAS mass flow in the final effluent. This study also provided evidence of soil contamination by the aerosol produced over the aeration basin and inadvertent spillage of pieces of sludge cake.

  • Simultaneous determination of perfluoroalkyl iodides, perfluoroalkane sulfonamides, Fluorotelomer alcohols, Fluorotelomer iodides and Fluorotelomer acrylates and methacrylates in water and sediments using solid-phase microextraction-gas chromatograph
    Journal of chromatography. A, 2016
    Co-Authors: Cristina Bach, Virginie Boiteux, Adeline Colin, Jessica Hemard, Christophe Rosin, Jean-françois Munoz, X. Dauchy
    Abstract:

    Here, we developed and validated a headspace-solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS) method for the determination of 14 volatile perfluorinated alkylated substances (PFASs) in water and sediment samples according to SANTE 11945/2015 guidelines. Three Fluorotelomer alcohols (FTOHs), two perfluoroalkyl iodides (PFIs), three Fluorotelomer iodides (FTIs), four Fluorotelomer acrylates and methacrylates (FTACs and FTMACs) and two perfluoroalkyl sulfonamides (FASAs) were analysed simultaneously to assess the occurrence of these compounds from their emission sources to the outlets in water treatment plants. Several SPME parameters were optimised for both water and sediment to maximise responses and keep analysis time to a minimum. In tap water, the limits of quantification (LOQs) were found to be between 20ng/L and 100ng/L depending on the analyte, with mean recoveries ranging from 76 to 126%. For sediments, LOQs ranged from 1 to 3ng/g dry weight depending on the target compound, with mean recoveries ranging from 74 to 125%. SPME considerably reduced sample preparation time and its use provided a sensitive, fast and simple technique. We then used this HS-SPME-GC/MS method to investigate the presence of volatile PFASs in the vicinity of an industrial facility. Only 8:2 FTOH and 10:2 FTOH were detected in a few water and sediment samples at sub-ppb concentration levels. Moreover, several non-target Fluorotelomers (12:2 FTOH, 14:2 FTOH and 10:2 FTI) were identified in raw effluent samples. These long-chain Fluorotelomers have high bioaccumulative potential in the aquatic environment compared with short-chain Fluorotelomers such as 6:2 FTOH and 6:2 FTI.

  • Relationship Between Industrial Discharges and Contamination of Raw Water Resources by Perfluorinated Compounds: Part II: Case Study of a Fluorotelomer Polymer Manufacturing Plant.
    Bulletin of Environmental Contamination and Toxicology, 2012
    Co-Authors: X. Dauchy, Virginie Boiteux, Christophe Rosin, Jean-françois Munoz
    Abstract:

    In this study, the concentrations of 10 perfluorinated compounds (PFCs) were measured in effluents of a Fluorotelomer polymer manufacturing plant and its wastewater treatment plant. A 50-fold increase between the two effluents mass flows was observed. The water quality of two drinking water treatment plants located downstream at 15 and 25 km from the manufacturing plant was examined. An increase of the sum of PFCs was observed between the river (30 ng/L) and an alluvial well (70 ng/L), and between the raw water (9 ng/L) and the outlet of a biological treatment (97 ng/L). These results indicate a possible degradation of Fluorotelomers, occurring during wastewater treatment, sediment infiltration in the alluvial aquifer, and drinking water treatment.