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McDonough CA, Li W, Bischel HN, De Silva AO, DeWitt JC. Widening the Lens on PFASs: Direct Human Exposure to Perfluoroalkyl Acid Precursors (pre-PFAAs). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:6004-6013. [PMID: 35324171 PMCID: PMC10782884 DOI: 10.1021/acs.est.2c00254] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Determining health risks associated with per-/polyfluoroalkyl substances (PFASs) is a highly complex problem requiring massive efforts for scientists, risk assessors, and regulators. Among the most poorly understood pressing questions is the relative importance of pre-PFAAs, which are PFASs that degrade to highly persistent perfluoroalkyl acids. How many of the vast number of existing pre-PFAAs are relevant for direct human exposure, and what are the predominant exposure pathways? What evidence of direct exposure to pre-PFAAs is provided by human biomonitoring studies? How important are pre-PFAAs and their biotransformation products for human health risk assessment? This article outlines recent progress and recommendations toward widening the lens on human PFAS exposure to include the pre-PFAA subclass.
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Affiliation(s)
- Carrie A. McDonough
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Wenting Li
- Department of Civil & Environmental Engineering, University of California Davis, Davis, CA 95616 USA
| | - Heather N. Bischel
- Department of Civil & Environmental Engineering, University of California Davis, Davis, CA 95616 USA
| | - Amila O. De Silva
- Aquatic Contaminants Research Division, Water Science Technology Directorate, Environment and Climate Change Canada, Burlington, Ontario L7S 1A1, Canada
| | - Jamie C. DeWitt
- Department of Pharmacology & Toxicology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
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2
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Bai FY, Deng MS, Chen MY, Kong L, Ni S, Zhao Z, Pan XM. Atmospheric oxidation of fluoroalcohols initiated by ˙OH radicals in the presence of water and mineral dusts: mechanism, kinetics, and risk assessment. Phys Chem Chem Phys 2021; 23:13115-13127. [PMID: 34075970 DOI: 10.1039/d1cp01324f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ˙OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the presence of O2/NO/NO2 was studied by using density functional theory and the direct kinetic method. The formation mechanisms of perfluorocarboxylic/hydroperfluorocarboxylic acids (PFCAs/H-PFCAs), which were produced from the reactions of α-hydroxyperoxy radicals with NO/NO2 and the ensuing oxidation of α-hydroxyalkoxy radicals, were clarified and discussed. The roles of water and silica particles in the rate constants and ˙OH reaction mechanism with fluoroalcohols were investigated theoretically. The results showed that water and silica particles do not alter the reaction mechanism but obviously change the kinetic properties. Water could retard fluoroalcohol degradation by decreasing the rate constants by 3-5 orders of magnitude. However, the heterogeneous ˙OH-rate coefficients on the silica particle surfaces, including H4SiO4, H6Si2O7, and H12Si6O18, are larger than that of the naked reaction by 1.20-24.50 times. This finding suggested that these heterogeneous reactions may be responsible for the atmospheric loss of fluoroalcohols and the burden of PFCAs. In addition, fluoroalcohols could be exothermically trapped by H12Si6O18, H6Si2O7, and H4SiO4, in which the chemisorption on H12Si6O18 is stronger than that on H6Si2O7 or H4SiO4. The global warming potentials and radiative forcing of CF3CF2CF2CH2OH/CF3CHFCF2CH2OH were calculated to assess their contributions to the greenhouse effect. The toxicities of individual species were also estimated via the ECOSAR program and experimental measurements. This work enhances the understanding of the environmental formation of PFCAs and the transformation of fluoroalcohols.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Ming-Shuai Deng
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Mei-Yan Chen
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Lian Kong
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Shuang Ni
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China. and State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Chang Ping, Beijing 102249, P. R. China
| | - Xiu-Mei Pan
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
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Liu M, Munoz G, Vo Duy S, Sauvé S, Liu J. Stability of Nitrogen-Containing Polyfluoroalkyl Substances in Aerobic Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4698-4708. [PMID: 33739092 DOI: 10.1021/acs.est.0c05811] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Zwitterionic per- and polyfluoroalkyl substances (PFASs) used in aqueous film-forming foams (AFFFs) could face diverse environmental fates once released at military bases, airports, fire-training areas, and accidental release sites. Here, we studied for the first time the transformation potential of four electrochemical fluorination (ECF)-based PFAS zwitterions (two carboxyl betaines and two tertiary amines) in aerobic soils. The two perfluoroalkyl sulfonamide derivatives were precursors to perfluorooctanesulfonate (PFOS), while the amide derivatives were precursors to perfluorooctane carboxylate (PFOA). These zwitterions and four other previously reported zwitterions or cations were compared for their transformation pathways and kinetics. Structural differences, especially the nitrogen head groups, largely influenced the persistence of these compounds in aerobic soils. The perfluoroalkyl sulfonamide-based compounds showed higher microbial stability than the corresponding perfluoroalkyl amide-based ones. Their stability in aerobic soils is ranked based on the magnitude of DT50 (time for 50% of substance to disappear): quaternary ammonium ≈ carboxyl betaine ≫ tertiary amine > amine oxide. The PFASs containing quaternary ammonium or betaine groups showed high stability in soils, with the longest DT50 likely to be years or decades, while those with tertiary amine or amine oxide groups showed DT50 of weeks or months. These eight ECF-based precursors provide insights into the degradation pathways and persistence in surface soils of other perfluoroalkyl cations and zwitterions present in AFFFs.
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Affiliation(s)
- Min Liu
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada
| | - Gabriel Munoz
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada
- Department of Chemistry, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Sung Vo Duy
- Department of Chemistry, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Sébastien Sauvé
- Department of Chemistry, Université de Montréal, Montreal, QC H3C 3J7, Canada
| | - Jinxia Liu
- Department of Civil Engineering, McGill University, Montreal, QC H3A 0C3, Canada
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Khan MY, So S, da Silva G. Decomposition kinetics of perfluorinated sulfonic acids. CHEMOSPHERE 2020; 238:124615. [PMID: 31454742 DOI: 10.1016/j.chemosphere.2019.124615] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 05/28/2023]
Abstract
Perfluorooctanesulfonic acid (PFOS) is a widespread and persistent pollutant of concern to human health and the environment. Although incineration is often used to treat material contaminated with PFOS and related per- and polyfluoroalkyl substances (PFAS), little is known about the precise chemical mechanism for the thermal decomposition of these substances of concern. Here, we present the first study of the thermal decomposition kinetics of PFOS and related perfluorinated acids, using computational chemistry and reaction rate theory methods. We discover that the preferred channel for PFOS decomposition is via an α-sultone that spontaneously decomposes to form perfluorooctanal and SO2. At 1000 K the halflife for PFOS is predicted to be 0.2 s, decreasing sharply as temperature increases further. These results show that the acid headgroup in PFOS can be efficiently destroyed in incinerators operating at relatively modest temperatures. The new insights provided into the exact decomposition mechanism and kinetics of PFOS will help to improve remediation technologies actively under development.
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Affiliation(s)
- M Yasir Khan
- Department of Chemical Engineering, University of Melbourne, Victoria, 3010, Australia
| | - Sui So
- Department of Chemical Engineering, University of Melbourne, Victoria, 3010, Australia
| | - Gabriel da Silva
- Department of Chemical Engineering, University of Melbourne, Victoria, 3010, Australia.
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Martin D, Munoz G, Mejia-Avendaño S, Duy SV, Yao Y, Volchek K, Brown CE, Liu J, Sauvé S. Zwitterionic, cationic, and anionic perfluoroalkyl and polyfluoroalkyl substances integrated into total oxidizable precursor assay of contaminated groundwater. Talanta 2019; 195:533-542. [DOI: 10.1016/j.talanta.2018.11.093] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/23/2018] [Accepted: 11/24/2018] [Indexed: 12/26/2022]
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De Silva AO, Spencer C, Ho KCD, Al Tarhuni M, Go C, Houde M, de Solla SR, Lavoie RA, King LE, Muir DCG, Fair PA, Wells RS, Bossart GD. Perfluoroalkylphosphinic Acids in Northern Pike (Esox lucius), Double-Crested Cormorants (Phalacrocorax auritus), and Bottlenose Dolphins (Tursiops truncatus) in Relation to Other Perfluoroalkyl Acids. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10903-10913. [PMID: 27677975 DOI: 10.1021/acs.est.6b03515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Perfluoroalkyl phosphinic acids (PFPIAs) are perfluoroalkyl acids (PFAAs) that are used for their surfactant properties in a variety of applications, resulting in their presence in environmental waters; however, they have not been widely studied in biota. A survey of PFPIAs was conducted in fish, dolphins, and birds from various locations in North America. Northern pike (Esox lucius) were collected at two locations in 2011 near Montréal Island in the St. Lawrence River, Canada, double-crested cormorants (Phalacrocorax auritus) were collected from bird colonies in the Great Lakes in 2010-2012, and bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, FL and Charleston Harbor, SC were sampled in 2004-2009. PFPIAs had a detection frequency of 100% in all animals. This is the first report of PFPIAs in fish, dolphin, and bird plasma. Total PFPIA levels (mean ± standard deviation, 1.87 ± 2.17 ng/g wet weight (ww), range of 0.112-15.3 ng/g ww) were 1-2 orders of magnitude lower than those of perfluoroalkyl carboxylates (PFCA) and perfluoroalkanesulfonates (PFSA) in the same samples. The predominant congeners were 6:8 PFPIA (cormorants and pike) and 6:6 PFPIA (dolphins). Total PFPIAs in cormorants from Hamilton Harbour (5.02 ± 2.80 ng/g ww) were statistically higher than in other areas and taxonomic groups. The ubiquity of PFPIAs warrants further research on sources and effects of these unique compounds.
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Affiliation(s)
- Amila O De Silva
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Christine Spencer
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Ki Chung D Ho
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Mohammed Al Tarhuni
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Christopher Go
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Magali Houde
- Environment and Climate Change Canada, Centre Saint-Laurent , Montréal, Quebec H2Y 2E7, Canada
| | - Shane R de Solla
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Raphael A Lavoie
- Biology Department, Queen's University , 116 Barrie Street, Kingston, Ontario K7L3N6 Canada
| | - Laura E King
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Derek C G Muir
- Environment and Climate Change Canada, Canada Centre for Inland Waters , Burlington, Ontario, L7S 1A1, Canada
| | - Patricia A Fair
- Center for Coastal Environmental Health and Biomolecular Research, NOS, NOAA , 219 Fort Johnson Road, Charleston, South Carolina 29142, United States
| | - Randall S Wells
- Chicago Zoological Society's Sarasota Dolphin Research Program, Mote Marine Laboratory , 1600 Ken Thompson Parkway, Sarasota, Florida 34236, United States
- Georgia Aquarium , 225 Baker Street, Atlanta, Georgia 30313, United States
| | - Gregory D Bossart
- Georgia Aquarium , 225 Baker Street, Atlanta, Georgia 30313, United States
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Brumovský M, Karásková P, Borghini M, Nizzetto L. Per- and polyfluoroalkyl substances in the Western Mediterranean Sea waters. CHEMOSPHERE 2016; 159:308-316. [PMID: 27314632 DOI: 10.1016/j.chemosphere.2016.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/31/2016] [Accepted: 06/03/2016] [Indexed: 05/20/2023]
Abstract
The spatial and temporal distribution of per- and polyfluoroalkyl substances (PFASs) in the open Western Mediterranean Sea waters was investigated in this study for the first time. In addition to surface water samples, a deep water sample (1390 m depth) collected in the center of the western basin was analyzed. Perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were detected in all samples and were the dominant PFASs found. The sum of PFAS concentrations (ΣPFASs) ranged 246-515 pg/L for surface water samples. PFASs in surface water had a relatively homogeneous distribution with levels similar to those previously measured in the Atlantic near the Strait of Gibraltar, in water masses feeding the inflow to the Mediterranean Sea. Higher concentrations of PFHxA, PFHpA and PFHxS were, however, found in the present study. Inflowing Atlantic water and river/coastal discharges are likely the major sources of PFASs to the Western Mediterranean basin. Slightly lower (factor of 2) ΣPFASs was found in the deep water sample (141 pg/L). Such a relatively high contamination of deep water is likely to be linked to recurring deep water renewal fed by downwelling events in the Gulf of Lion and/or Ligurian Sea.
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Affiliation(s)
- Miroslav Brumovský
- RECETOX - Research Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic.
| | - Pavlína Karásková
- RECETOX - Research Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic
| | - Mireno Borghini
- CNR, Ist Sci Marine, I-19032 Pozzuolo di Lerici, La Spezia, Italy
| | - Luca Nizzetto
- RECETOX - Research Centre for Toxic Compounds in the Environment, Masaryk University, Kamenice 753/5, 625 00 Brno, Czech Republic; NIVA - Norwegian Institute for Water Research, Gaustadalléen 21, 0349 Oslo, Norway
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Anderson RH, Long GC, Porter RC, Anderson JK. Occurrence of select perfluoroalkyl substances at U.S. Air Force aqueous film-forming foam release sites other than fire-training areas: Field-validation of critical fate and transport properties. CHEMOSPHERE 2016; 150:678-685. [PMID: 26786021 DOI: 10.1016/j.chemosphere.2016.01.014] [Citation(s) in RCA: 203] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 12/15/2015] [Accepted: 01/05/2016] [Indexed: 05/22/2023]
Abstract
The use of aqueous film-forming foam (AFFF) to extinguish hydrocarbon-based fires is recognized as a significant source of environmental poly- and perfluoroalkyl substances (PFASs). Although the occurrence of select PFASs in soil and groundwater at former fire-training areas (FTAs) at military installations operable since 1970 has been consistently confirmed, studies reporting the occurrence of PFASs at other AFFF-impacted sites (e.g. emergency response locations, AFFF lagoons, hangar-related AFFF storage tanks and pipelines, and fire station testing and maintenance areas) are largely missing from the literature. Further, studies have mostly focused on a single site (i.e., FTAs at military installations) and, thus, lack a comparison of sites with diverse AFFF release history. Therefore, the purpose of this investigation was to evaluate select PFAS occurrence at non-FTA sites on active U.S. Air Force installations with historic AFFF use of varying magnitude. Concentrations of fifteen perfluoroalkyl acids (PFAAs) and perfluorooctane sulfonamide (PFOSA), an important PFOS precursor, were measured from several hundred samples among multiple media (i.e., surface soil, subsurface soil, sediment, surface water, and groundwater) collected from forty AFFF-impacted sites across ten installations between March and September 2014, representing one of the most comprehensive datasets on environmental PFAS occurrence to date. Differences in detection frequencies and observed concentrations due to AFFF release volume are presented along with rigorous data analyses that quantitatively demonstrate phase-dependent (i.e., solid-phase vs aqueous-phase) differences in the chemical signature as a function of carbon chain-length and in situ PFOS (and to a slightly lesser extent PFHxS) formation, presumably due to precursor biotransformation.
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Sun Y, Zhang Q, Wang H, Wang W. OH radical-initiated oxidation degradation and atmospheric lifetime of N-ethylperfluorobutyramide in the presence of O₂/NOx. CHEMOSPHERE 2015; 134:241-249. [PMID: 25957036 DOI: 10.1016/j.chemosphere.2015.04.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/20/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
The OH radical-initiated oxidation degradation of N-ethylperfluorobutyramide (EtFBA) in the presence of O2/NOx was investigated theoretically by using density functional theory (DFT). All possible pathways involved in the oxidation process were presented and discussed. The study shows that the H abstraction from the C(2)H(2) group in EtFBA is the most energetically favorable because of the lowest barrier and highest exothermicity. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants over the temperature range of 180-370 K. At 296 K, the calculated overall rate constant of EtFBA with OH radicals is 2.50 × 10(-12)cm(3)molecule(-1)s(-1). The atmospheric lifetime of EtFBA determined by OH radicals is short, about 4.6 days at 296K. However, the atmospheric lifetimes of its primary oxidation products, C3F7C(O)N(H)C(O)CH3, C3F7C(O)N(H)CH2CHO and C3F7C(O)NH2, are much longer, about 30-50 days. It demonstrates the possibility that the atmospheric oxidation degradation of polyfluorinated amides (PFAMs) contributes to the burden of observed perfluorinated pollutants in the Arctic region. This study reveals for the first time that the water molecule plays an important catalytic effect on several key elementary steps and promotes the degradation potential of EtFBA.
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Affiliation(s)
- Yanhui Sun
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China.
| | - Hui Wang
- School of Environment, Tsinghua University, Beijing 100084, PR China.
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
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Feng M, Qu R, Wei Z, Wang L, Sun P, Wang Z. Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment. Sci Rep 2015; 5:9859. [PMID: 25947254 PMCID: PMC5386195 DOI: 10.1038/srep09859] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 03/24/2015] [Indexed: 12/03/2022] Open
Abstract
The thermal decomposition of Nafion N117 membrane, a typical perfluorosulfonic acid membrane that is widely used in various chemical technologies, was investigated in this study. Structural identification of thermolysis products in water and methanol was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). The fluoride release was studied using an ion-chromatography system, and the membrane thermal stability was characterized by thermogravimetric analysis. Notably, several types of perfluorinated compounds (PFCs) including perfluorocarboxylic acids were detected and identified. Based on these data, a thermolysis mechanism was proposed involving cleavage of both the polymer backbone and its side chains by attack of radical species. This is the first systematic report on the thermolysis products of Nafion by simulating its high-temperature operation and disposal process via incineration. The results of this study indicate that Nafion is a potential environmental source of PFCs, which have attracted growing interest and concern in recent years. Additionally, this study provides an analytical justification of the LC/ESI-MS/MS method for characterizing the degradation products of polymer electrolyte membranes. These identifications can substantially facilitate an understanding of their decomposition mechanisms and offer insight into the proper utilization and effective management on these membranes.
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Affiliation(s)
- Mingbao Feng
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Ruijuan Qu
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Zhongbo Wei
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Liansheng Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Ping Sun
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Zunyao Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, P. R. China
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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. ENVIRONMENT INTERNATIONAL 2014; 70:62-75. [PMID: 24932785 DOI: 10.1016/j.envint.2014.04.013] [Citation(s) in RCA: 412] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [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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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. ENVIRONMENT INTERNATIONAL 2014; 69:166-76. [PMID: 24861268 DOI: 10.1016/j.envint.2014.04.006] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [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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Borduas N, da Silva G, Murphy JG, Abbatt JPD. Experimental and theoretical understanding of the gas phase oxidation of atmospheric amides with OH radicals: kinetics, products, and mechanisms. J Phys Chem A 2014; 119:4298-308. [PMID: 25019427 DOI: 10.1021/jp503759f] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Atmospheric amides have primary and secondary sources and are present in ambient air at low pptv levels. To better assess the fate of amides in the atmosphere, the room temperature (298 ± 3 K) rate coefficients of five different amides with OH radicals were determined in a 1 m(3) smog chamber using online proton-transfer-reaction mass spectrometry (PTR-MS). Formamide, the simplest amide, has a rate coefficient of (4.44 ± 0.46) × 10(-12) cm(3) molec(-1) s(-1) against OH, translating to an atmospheric lifetime of ∼1 day. N-methylformamide, N-methylacetamide and propanamide, alkyl versions of formamide, have rate coefficients of (10.1 ± 0.6) × 10(-12), (5.42 ± 0.19) × 10(-12), and (1.78 ± 0.43) × 10(-12) cm(3) molec(-1) s(-1), respectively. Acetamide was also investigated, but due to its slow oxidation kinetics, we report a range of (0.4-1.1) × 10(-12) cm(3) molec(-1) s(-1) for its rate coefficient with OH radicals. Oxidation products were monitored and quantified and their time traces were fitted using a simple kinetic box model. To further probe the mechanism, ab initio calculations are used to identify the initial radical products of the amide reactions with OH. Our results indicate that N-H abstractions are negligible in all cases, in contrast to what is predicted by structure-activity relationships. Instead, the reactions proceed via C-H abstraction from alkyl groups and from formyl C(O)-H bonds when available. The latter process leads to radicals that can readily react with O2 to form isocyanates, explaining the detection of toxic compounds such as isocyanic acid (HNCO) and methyl isocyanate (CH3NCO). These contaminants of significant interest are primary oxidation products in the photochemical oxidation of formamide and N-methylformamide, respectively.
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Affiliation(s)
- Nadine Borduas
- †Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Gabriel da Silva
- ‡Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia
| | - Jennifer G Murphy
- †Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Jonathan P D Abbatt
- †Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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15
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Liu J, Mejia Avendaño S. Microbial degradation of polyfluoroalkyl chemicals in the environment: a review. ENVIRONMENT INTERNATIONAL 2013; 61:98-114. [PMID: 24126208 DOI: 10.1016/j.envint.2013.08.022] [Citation(s) in RCA: 271] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 08/22/2013] [Accepted: 08/26/2013] [Indexed: 05/20/2023]
Abstract
Polyfluoroalkyl chemicals containing perfluoroalkyl moieties have been widely used in numerous industrial and commercial applications. Many polyfluoroalkyl chemicals are potential perfluoroalkyl acid (PFAA) precursors. When they are released to the environment, abiotic and microbial degradation of non-fluorinated functionalities, polyfluoroalkyl and perfluoroalkyl moieties can result in perfluoroalkyl carboxylic (PFCAs) and sulfonic acids (PFSAs), such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These highly persistent and ubiquitously detected PFAAs are the subjects of many regulations and actions due to their toxic profiles. In order to confidently evaluate the environmental fate and effects of these precursors and their links to PFSAs and PFCAs, we present the review into the environmental biodegradability studies carried out with microbial culture, activated sludge, soil and sediment in the past decade. First, we propose that the knowledge gap caused by the lack of direct detection of precursor chemicals in environmental samples can be bridged by laboratory investigations of important precursors such as fluorotelomer-based compounds and perfluoroalkane sulfonamido derivatives. Then we evaluate the experimental setups and methodologies, sampling and sample preparation methods, and analytical techniques that have been successfully applied. Third, we provide the most updated knowledge on quantitative and qualitative relationships between precursors and PFSAs or PFCAs, microbial degradation pathways, half-lives of precursors, defluorination potential, and novel degradation intermediates and products. In the end, we identify knowledge gaps and suggest research directions with regard to future biodegradation studies, environmental monitoring and ecotoxicological assessment of perfluoroalkyl and polyfluoroalkyl chemicals.
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Affiliation(s)
- Jinxia Liu
- Department of Civil Engineering, McGill University, Montreal, Quebec H3A 0C3, Canada.
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