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Goukeh MN, Abichou T, Tang Y. Measurement of fluorotelomer alcohols based on solid phase microextraction followed by gas chromatography-mass spectrometry and its application in solid waste study. CHEMOSPHERE 2023; 345:140460. [PMID: 37852384 DOI: 10.1016/j.chemosphere.2023.140460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/13/2023] [Accepted: 10/14/2023] [Indexed: 10/20/2023]
Abstract
This work developed a method based on solid phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS) for the measurement of fluorotelomer alcohols (FTOHs) in gas samples. The method quantification limit (MQL) is 6-7 ng/L for 6:2 fluorotelomer alcohols (6:2 FTOH) and 8:2 fluorotelomer alcohols (8:2 FTOH). In contrast to common methods such as thermal desorption combined with GC-MS, it needs neither pre-concentration equipment nor large sample volume. The extraction-evaporation-GC/MS is commonly used in literature for FTOHs measurement in solids samples. We developed a method to measure FTOHs in solid samples by adding solvent extraction prior to headspace SPME-GC/MS. The extraction-headspace SPME-GC/MS method has a quantification limit of 40-43 ng per gram for 6:2 FTOH and 8:2 FTOH in solid samples. This is comparable to the MQLs for the extraction-evaporation-GC/MS method. Removing the solvent evaporation step decreased the risk of contamination and loss of analytes. The developed methods were successfully used in three examples of solid waste study: 1) measuring 6:2 FTOH and 8:2 FTOH above the MQL in gas emissions from a closed landfill, 2) finding 6:2 FTOH above MQL in 9 of 31 solid consumer products, and 3) finding that the release of 6:2 FTOH in simulated landfills containing popcorn bags was linear at a rate of 3.15 ng/g popcorn bags-day and that partial 6:2 FTOH was from the hydrolysis of precursors.
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Affiliation(s)
- Mojtaba Nouri Goukeh
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL, 32310, United States
| | - Tarek Abichou
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL, 32310, United States
| | - Youneng Tang
- Department of Civil and Environmental Engineering, FAMU-FSU College of Engineering, Florida State University, 2525 Pottsdamer Street, Tallahassee, FL, 32310, United States.
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2
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Wu S, Zhu L, Ye Q, Zhu Y, Zhang T, Chen X, Zhong W. Mechanisms for the structural dependent transformation of 6:2 and 8:2 polyfluoroalkyl phosphate diesters in wheat (Triticum aestivum L.). JOURNAL OF HAZARDOUS MATERIALS 2023; 454:131536. [PMID: 37146340 DOI: 10.1016/j.jhazmat.2023.131536] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/25/2023] [Accepted: 04/27/2023] [Indexed: 05/07/2023]
Abstract
Polyfluoroalkyl phosphate esters (PAPs) are widely used and detected in various environmental media and organisms, but little is known about their behaviors in plants. In this study, the uptake, translocation and transformation of 6:2 and 8:2 diPAP in wheat using hydroponic experiments were investigated. 6:2 diPAP was more easily taken up by roots and translocated to shoots than 8:2 diPAP. Their phase I metabolites were fluorotelomer saturated carboxylates (FTCAs), fluorotelomer unsaturated carboxylates (FTUCAs) and perfluoroalkyl carboxylic acids (PFCAs). PFCAs with even-numbered chain length were the primary phase I terminal metabolites suggesting that they were mainly generated through β-oxidation. Cysteine and sulfate conjugates were the primary phase II transformation metabolites. The higher levels and ratios of phase II metabolites in the 6:2 diPAP exposure group indicated that the phase I metabolites of 6:2 diPAP were more susceptible to phase II transformation than that of 8:2 diPAP, which was confirmed by density functional theory calculation. Enzyme activity analyses and in vitro experiments demonstrated that cytochrome P450 and alcohol dehydrogenase actively participated in the phase Ⅰ transformation of diPAPs. Gene expression analyses showed that glutathione S-transferase (GST) was involved in the phase Ⅱ transformation, and the subfamily GSTU2 played a dominant role.
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Affiliation(s)
- Sihan Wu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Qingqing Ye
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Yumin Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Tianxu Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Xin Chen
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China
| | - Wenjue Zhong
- Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education), Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China.
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Xia Y, Hao L, Li Y, Li Y, Chen J, Li L, Han X, Liu Y, Wang X, Li D. Embryonic 6:2 FTOH exposure causes reproductive toxicity by disrupting the formation of the blood-testis barrier in offspring mice. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 250:114497. [PMID: 36608565 DOI: 10.1016/j.ecoenv.2023.114497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/31/2022] [Accepted: 01/01/2023] [Indexed: 06/17/2023]
Abstract
Previous studies have revealed nephrotoxicity, hepatotoxicity, subchronic developmental and reproductive toxicity in rats exposed to fluorotelomer alcohol (FTOH). However, the effects of embryonic 6:2 FTOH exposure on the reproductive system of offspring mice remain unclear. The purpose of this study is to explore the reproductive toxic effects of embryonic 6:2 FTOH exposure on offspring male mice and the related molecular mechanisms. Therefore, the pregnant mice were given corn oil or 6:2 FTOH by gavage from gestational days 12.5-21.5. The results demonstrated that embryonic 6:2 FTOH exposure resulted in disrupted testicular structure, low expression of tight junction protein between Sertoli cells (SCs), impaired blood-testis barrier (BTB) formation and maturation, reduced sperm viability and increased malformation, and induced testicular inflammation in the offspring of mice. Further in vitro studies showed that 6:2 FTOH treatment upregulated MMP-8 expression by activating AKT/NF-κB signaling pathway, which in turn enhanced occludin cleavage leading to the disruption of SCs barrier integrity. In summary, this study demonstrated that 6:2 FTOH exposure caused reproductive dysfunction in male offspring through disruption of BTB, which provided new insights into the effects of 6:2 FTOH exposure on the offspring.
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Affiliation(s)
- Yunhui Xia
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Lanxiang Hao
- Endocrinology Department, Yancheng First Hospital, Affiliated Hospital of Nanjing University Medical School; The First people's Hospital of Yancheng, Yancheng, Jiangsu 224001, China
| | - Yueyang Li
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China
| | - Yifan Li
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Junhan Chen
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Lei Li
- Endocrinology Department, Yancheng First Hospital, Affiliated Hospital of Nanjing University Medical School; The First people's Hospital of Yancheng, Yancheng, Jiangsu 224001, China
| | - Xiaodong Han
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Yanmei Liu
- Endocrinology Department, Yancheng First Hospital, Affiliated Hospital of Nanjing University Medical School; The First people's Hospital of Yancheng, Yancheng, Jiangsu 224001, China.
| | - Xiaojian Wang
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing, Jiangsu 211816, China.
| | - Dongmei Li
- Immunology and Reproduction Biology Laboratory & State Key Laboratory of Analytical Chemistry for Life Science, Medical School, Nanjing University, Nanjing, Jiangsu 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu 210093, China.
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Kolanczyk RC, Saley MR, Serrano JA, Daley SM, Tapper MA. PFAS Biotransformation Pathways: A Species Comparison Study. TOXICS 2023; 11:toxics11010074. [PMID: 36668800 PMCID: PMC9862377 DOI: 10.3390/toxics11010074] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/05/2023] [Accepted: 01/07/2023] [Indexed: 05/30/2023]
Abstract
Limited availability of fish metabolic pathways for PFAS may lead to risk assessments with inherent uncertainties based only upon the parent chemical or the assumption that the biodegradation or mammalian metabolism map data will serve as an adequate surrogate. A rapid and transparent process, utilizing a recently created database of systematically collected information for fish, mammals, poultry, plant, earthworm, sediment, sludge, bacteria, and fungus using data evaluation tools in the previously described metabolism pathway software system MetaPath, is presented. The fish metabolism maps for 10 PFAS, heptadecafluorooctyl(tridecafluorohexyl)phosphinic acid (C6/C8 PFPiA), bis(perfluorooctyl)phosphinic acid (C8/C8 PFPiA), 2-[(6-chloro-1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl)oxy]-1,1,2,2-tetrafluoroethanesulfonic acid (6:2 Cl-PFESA), N-Ethylperfluorooctane-1-sulfonamide (Sulfuramid; N-EtFOSA), N-Ethyl Perfluorooctane Sulfonamido Ethanol phosphate diester (SAmPAP), Perfluorooctanesulfonamide (FOSA), 8:2 Fluorotelomer phosphate diester (8:2 diPAP), 8:2 fluorotelomer alcohol (8:2 FTOH), 10:2 fluorotelomer alcohol (10:2 FTOH), and 6:2 fluorotelomer sulfonamide alkylbetaine (6:2 FTAB), were compared across multiple species and systems. The approach demonstrates how comparisons of metabolic maps across species are aided by considering the sample matrix in which metabolites were quantified for each species, differences in analytical methods used to identify metabolites in each study, and the relative amounts of metabolites quantified. Overall, the pathways appear to be well conserved across species and systems. For PFAS lacking a fish metabolism study, a composite map consisting of all available maps would serve as the best basis for metabolite prediction. This emphasizes the importance and utility of collating metabolism into a searchable database such as that created in this effort.
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Affiliation(s)
- Richard C. Kolanczyk
- Great Lakes Toxicology and Ecology Division, Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Megan R. Saley
- Oak Ridge Institute for Science and Education, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Jose A. Serrano
- Great Lakes Toxicology and Ecology Division, Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Sara M. Daley
- Oak Ridge Institute for Science and Education, Great Lakes Toxicology and Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Mark A. Tapper
- Great Lakes Toxicology and Ecology Division, Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency, 6201 Congdon Blvd., Duluth, MN 55804, USA
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Amstutz VH, Cengo A, Gehres F, Sijm DTHM, Vrolijk MF. Investigating the cytotoxicity of per- and polyfluoroalkyl substances in HepG2 cells: A structure-activity relationship approach. Toxicology 2022; 480:153312. [PMID: 36075290 DOI: 10.1016/j.tox.2022.153312] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/25/2022] [Accepted: 09/02/2022] [Indexed: 11/18/2022]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a family of man-made chemicals with currently over 4'700 compounds identified. While toxicological data are available for some of the legacy PFAS, such as PFOA and PFOS, a knowledge gap remains concerning both emerging and legacy PFAS' toxicity due to the diversity of the PFAS. Therefore, a better understanding of the PFAS structure-activity relationship may prove helpful. The present study investigated a potential structure-activity relationship between PFAS and hepatotoxicity. As such, the effects of thirteen PFAS with varying carbon chain-length and functional head-groups (in a concentration range of 0-800 µM) on the cell viability of HepG2 cells and intracellular reactive oxygen species formation have been tested using the MTT and DCFH assay, respectively. The exposure times were either 3 or 24 h. In addition, intracellular PFAS levels were determined in HepG2 after 24 h exposure. The present study demonstrated that the cytotoxicity of PFAS is dependent on their chain-length as cell viability decreased with increasing chain-length at both exposure times. Calculated Relative Potency Factors (RPF), based on the TC50 values, were used for a tentative ranking of PFAS regarding their hepatotoxicity: PFNA ˃ PFDA ˃ PFOS ≥ PFOA ˃ PFHxS ˃ PFBS ˃˃ PFHpA = PFHxA = PFBA = PFPrA = 6:2 FTOH = 4:2 = FTOH = 3:1 FTOH. Similar results were observed regarding intracellular reactive oxygen species generation at both exposure times, with a tentative ranking of: PFNA ˃ PFOS ˃ PFOA ≥ PFDA ˃ PFHxS ˃ PFBS ˃ PFBA ˃ PFHpA ≥ PFHxA ˃ PFPrA ˃ 6:2 FTOH = 4:2 FTOH = 3:1 FTOH. Moreover, a concentration-dependent reactive oxygen species generation has been observed for all PFSAs and PFCAs, but not for the FTOHs. In conclusion, the carbon chain-length and functional head-group of a PFAS determine their in vitro toxicity for the two toxicological endpoints assessed in the present study. Moreover, no effects were observed for the tested FTOHs. As such, the present study established a potential structure-activity relationship that opens the possibility of developing a predictive model to help with the risk assessment of PFAS in the future.
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Affiliation(s)
- V H Amstutz
- Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands.
| | - A Cengo
- Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - F Gehres
- Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands; Office for Risk Assessment and Research, Netherlands Food and Consumer Product Safety Authority (NVWA), 3540 AA Utrecht, the Netherlands
| | - D T H M Sijm
- Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands; Office for Risk Assessment and Research, Netherlands Food and Consumer Product Safety Authority (NVWA), 3540 AA Utrecht, the Netherlands
| | - M F Vrolijk
- Department of Pharmacology and Toxicology, Maastricht University, 6229 ER Maastricht, the Netherlands
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Daramola O, Rand AA. Emerging investigator series: human CYP2A6 catalyzes the oxidation of 6:2 fluorotelomer alcohol. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1688-1695. [PMID: 34734218 DOI: 10.1039/d1em00307k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The biotransformation of 6:2 fluorotelomer alcohol (6:2 FTOH) results in the production of bioactive and persistent metabolites, including perfluorinated carboxylic acids (PFCAs). While the products of 6:2 FTOH metabolism have been elucidated in several animal models, the responsible cytochrome P450 (CYP) isoform(s) have not been reported. Here, we characterized the in vitro oxidation of 6:2 FTOH using human liver microsomes and recombinant human CYPs. Six major xenobiotic metabolizing CYPs were screened for their capacity to catalyze 6:2 FTOH oxidation using chemical inhibitors selective towards CYP isoforms. Of the CYP isoforms investigated, CYP2A6 was the only enzyme capable of catalyzing 6:2 FTOH in human liver microsomes, with KM and Vmax values of 4076 ng mL-1 and 69 ng mL-1 min-1, respectively. We further probed the metabolic mechanism by plotting the 6:2 FTOH kinetic profile and extrapolating data to several possible kinetic models. 6:2 FTOH oxidation followed the typical one-site Michaelis-Menten kinetic model. This study also reports that 6:2 FTOH loss is associated with active CYP2A6 by incubating microsomes with the selective CYP2A6 inhibitor tranylcypromine, which bound competitively to the enzyme as determined by an increased KM (8796 ng mL-1) but unchanged Vmax value. Collectively, these findings provide a mechanistic perspective on the potential importance of CYP2A6 in the metabolic activation and phase I elimination of 6:2 FTOH and indirect human exposure to PFCAs.
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Affiliation(s)
- Oluwadamilola Daramola
- Department of Chemistry and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
| | - Amy A Rand
- Department of Chemistry and Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
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Zhao S, Liu T, Zhu L, Yang L, Zong Y, Zhao H, Hu L, Zhan J. Formation of perfluorocarboxylic acids (PFCAs) during the exposure of earthworms to 6:2 fluorotelomer sulfonic acid (6:2 FTSA). THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 760:143356. [PMID: 33158528 DOI: 10.1016/j.scitotenv.2020.143356] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/22/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
6:2 fluorotelomer sulfonic acid (6:2 FTSA) is a novel perfluorooctane sulfonate (PFOS) alternative used globally in aqueous film forming foams (AFFFs). Although 6:2 FTSA has been recently detected in the environment, its fate in terrestrial invertebrates remains unclear. The uptake, elimination and biotransformation of 6:2 FTSA in earthworms (Eisenia fetida) were investigated after in vivo and in vitro exposure. 6:2 FTSA could be biodegraded by microorganisms in soil to trifluoroacetic acid (TFA), perfluoropropionic acid (PFPrA), perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA). The uptake rate constant (ku) and biota-to-soil accumulation factor (BSAF) of 6:2 FTSA in earthworms were 0.185 goc/gww/d and 0.685 goc/gww, respectively, indicating high bioaccumulative ability in earthworms. Five terminal perfluorocarboxylic acids (PFCAs) metabolites, including TFA, PFPrA, PFBA, PFPeA and PFHxA were observed in both in vivo and in vitro exposure tests, with TFA as the predominant metabolite. However, no perfluoroheptanoic acid (PFHpA) was observed in the present study. The elimination rate constants (ke) increased in the order: 6:2 FTSA (0.057/d) < TFA (0.058/d) < PFPrA (0.071/d) < PFBA (0.084/d) < PFHxA (0.182/d) < PFPeA (0.193/d). Biodegradation of 6:2 FTSA in the earthworm homogenates, cytolchrome P450 (CYP450) enzyme solutions and glutathione-s-transferase (GST) enzyme solutions fitted well with the first order kinetics. The biotransformation rate constants (k) were in the following order: homogenates (0.012/h) > CYP450 (0.009/h) > GST (0.007/h), implying that CYP450 and GST were involved in biotransformation of 6:2 FTSA in earthworms. This study provides important theoretical evidence for the fate of 6:2 FTSA in earthworms.
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Affiliation(s)
- Shuyan Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China.
| | - Tianqi Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Liping Yang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Yvlu Zong
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
| | - Huanting Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
| | - Longhui Hu
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
| | - Jingjing Zhan
- Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Ocean Science and Technology, Dalian University of Technology, Panjin 124221, Liaoning, PR China
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Yang Y, Meng K, Chen M, Xie S, Chen D. Fluorotelomer Alcohols' Toxicology Correlates with Oxidative Stress and Metabolism. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 256:71-101. [PMID: 33866421 DOI: 10.1007/398_2020_57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fluorotelomer alcohols (FTOHs) are widely used as industrial raw materials due to their unique hydrophobic and oleophobic properties. However, because of accidental exposure to products containing FTOHs or with the widespread use of FTOHs, they tend to contaminate the water and the soil. There are reports demonstrating that FTOHs can cause various harmful effects in animals and humans (for example, neurotoxicity, hepatotoxicity, nephrotoxicity, immunotoxicity, endocrine-disrupting activity, and developmental and reproductive toxicities). Oxidative stress is related to a variety of toxic effects induced by FTOHs. To date, few reviews have addressed the relationship between the toxicity of FTOHs and oxidative stress. This article summarises research demonstrating that the toxicity induced by FTOHs correlates with oxidative stress and metabolism. Furthermore, during the metabolic process of FTOHs, a number of cytochrome P450 enzymes (CYP450) are involved and many metabolites are produced by these enzymes, which can induce oxidative stress. This is also reviewed.
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Affiliation(s)
- Yujuan Yang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Kuiyu Meng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Min Chen
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Shuyu Xie
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China
| | - Dongmei Chen
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, China.
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China.
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Xie S, Cui Y, Yang Y, Meng K, Pan Y, Liu Z, Chen D. Tissue distribution and bioaccumulation of 8:2 fluorotelomer alcohol and its metabolites in pigs after oral exposure. CHEMOSPHERE 2020; 249:126016. [PMID: 32062561 DOI: 10.1016/j.chemosphere.2020.126016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
The tissue distribution and bioaccumulation of 8:2 fluorotelomer alcohol (8:2 FTOH) were evaluated in pigs after oral exposure of a dose of 5 mg/kg.b.w.d. for 7 d. The bioaccumulation of 8:2 FTOH and its metabolites showed significant differences among the various tissues. The parent compound was quickly depleted, and the main metabolites perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and 3-perfluoroheptyl propanoic acid (7:3 FTCA) were detected in all tissues examined. The relative elimination half-life (T1/2re) calculated by compound concentration of 7:3 FTCA and PFOA was longest in kidney tissue (8.60 and 23.9 d, respectively), while their absolute elimination half-life (T1/2ab) of 7:3 FTCA and PFOA calculated by compound amount was longest in kidney tissue (10.41 and 64.1 d, respectively). The T1/2re and T1/2ab for PFHpA was longest in heart tissue (19.3 d and 30.26 d, respectively).The accumulated PFOA in kidney and liver tissues was still above the detection limit (LOD) at 21 d postdosing. These results indicate that PFOA and the kidneys are the ideal biomonitoring marker and target tissue, respectively, for 8:2 FTOH pollution. The T1/2 values of the main metabolites were of long duration compared to the growth cycle of farmed pigs (approximately 180 d) before slaughter; therefore, pigs contaminated with 8:2 FTOH present a potential risk to humans.
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Affiliation(s)
- Shuyu Xie
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China
| | - Yonghui Cui
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yujuan Yang
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China
| | - Kuiyu Meng
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China
| | - Yuanhu Pan
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China
| | - Zhenli Liu
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China
| | - Dongmei Chen
- National Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues, Wuhan, Hubei, 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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10
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Joudan S, Liu R, D'eon JC, Mabury SA. Unique analytical considerations for laboratory studies identifying metabolic products of per- and polyfluoroalkyl substances (PFASs). Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.02.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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11
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Zhang H, Wen B, Huang H, Wang S, Cai Z, Zhang S. Biotransformation of 6:2 fluorotelomer alcohol by the whole soybean (Glycine max L. Merrill) seedlings. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 257:113513. [PMID: 31733959 DOI: 10.1016/j.envpol.2019.113513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/13/2019] [Accepted: 10/28/2019] [Indexed: 05/27/2023]
Abstract
Fluorotelomer alcohols (FTOHs) are important precursors of perfluorocarboxylic acids (PFCAs) in the environment and biota. With the growing application of 6:2 FTOH [F(CF2)6CH2CH2OH] in product formulation, it is becoming increasingly urgent to investigate its biological fates in different species. In this study, biotransformation of 6:2 FTOH by young soybean plants (Glycine max L. Merrill) were investigated using hydroponic experiments. During the 144 h-exposure, 6:2 FTCA [F(CF2)6CH2COOH], 6:2 FTUCA [F(CF2)5CFCHCOOH], 5:3 FTUCA [F(CF2)5CHCHCOOH], 5:3 FTCA [F(CF2)5CH2CH2COOH], PFHxA [F(CF2)5COOH] and PFPeA [F(CF2)4COOH] were phase I metabolites in soybean. At the end of exposure, 5:3 FTCA (5.08 mol%), PFHxA (2.34 mol%) and PFPeA (0.58 mol%) were three main metabolites in soybean-solution system. 5:3 FTCA was predominant in soybean roots and stems, while PFHxA was the most abundant product in leaves. PFBA [F(CF2)3COOH] and 4:3 FTCA [F(CF2)4CH2CH2COOH] detected in the hydroponic solution most-likely came from the transformation of 5:3 FTCA by root-associated microbes. Moreover, phase II metabolites of 6:2 FTOH were identified and monitored in soybean tissues. Alcohol dehydrogenase, aldehyde dehydrogenase and glutathione S-transferase were found to participate in 6:2 FTOH metabolism. Based on the phase I and phase II metabolism of 6:2 FTOH in soybean, this study for the first time provides evidences for the transformation pathways of 6:2 FTOH in plants.
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Affiliation(s)
- Hongna Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong 999077, China
| | - Bei Wen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Honglin Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Sen Wang
- Department of Environmental Sciences, College of Urban and Environmental Sciences, Northwest University, Xi'an, 710027, China
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong 999077, China
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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12
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Kabadi SV, Fisher JW, Doerge DR, Mehta D, Aungst J, Rice P. Characterizing biopersistence potential of the metabolite 5:3 fluorotelomer carboxylic acid after repeated oral exposure to the 6:2 fluorotelomer alcohol. Toxicol Appl Pharmacol 2020; 388:114878. [PMID: 31923437 DOI: 10.1016/j.taap.2020.114878] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/05/2019] [Accepted: 01/04/2020] [Indexed: 01/09/2023]
Abstract
Our previous report on pharmacokinetic (PK) evaluation of 6:2 fluorotelomer alcohol (6:2 FTOH) examined the biopersistence potential of its metabolites based on data published from single inhalation and occupational 6:2 FTOH exposure studies. We calculated internal exposure estimates of three key metabolites of 6:2 FTOH, of which 5:3 fluorotelomer carboxylic acid (5:3 acid) had the highest internal exposure and the slowest clearance. No oral repeated 6:2 FTOH exposure data were available at the time to fully characterize the biopersistence potential of the metabolite 5:3 acid. We recently received additional data on 6:2 FTOH and 5:3 acid, which included a 90-day toxicokinetic study report on repeated oral 6:2 FTOH exposure to rats. We reviewed the study and analyzed the reported 5:3 acid concentrations in plasma, liver, and fat using one-compartment PK modeling and calculated elimination rate constants (kel), elimination half-lives (t1/2) and times to steady state (tss) of 5:3 acid at three 6:2 FTOH doses. Our results showed that tss of 5:3 acid in plasma and evaluated tissues were approximately close to 1 year, such that the majority of highest values were observed at the lowest 6:2 FTOH dose, indicating its association with the biopersistence of 6:2 FTOH. The results of our PK analysis are the first to characterize biopersistence potential of the 5:3 acid after repeated oral exposure to the parent compound 6:2 FTOH based on steady state PK parameters, and therefore, may have an impact on future study designs when conducting toxicity assays for such compounds.
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Affiliation(s)
- Shruti V Kabadi
- FDA/CFSAN/OFAS/DFCS, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States of America.
| | - Jeffrey W Fisher
- FDA/NCTR/DBT, 3900 NCTR Road, Jefferson, AR 72079, United States of America
| | - Daniel R Doerge
- FDA/NCTR/DBT, 3900 NCTR Road, Jefferson, AR 72079, United States of America
| | - Darshan Mehta
- FDA/NCTR/DBT, 3900 NCTR Road, Jefferson, AR 72079, United States of America
| | - Jason Aungst
- FDA/CFSAN/OFAS/DFCS, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States of America
| | - Penelope Rice
- FDA/CFSAN/OFAS/DFCS, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States of America
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13
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Zhao S, Wang B, Zhong Z, Liu T, Liang T, Zhan J. Contributions of enzymes and gut microbes to biotransformation of perfluorooctane sulfonamide in earthworms (Eisenia fetida). CHEMOSPHERE 2020; 238:124619. [PMID: 31450114 DOI: 10.1016/j.chemosphere.2019.124619] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/18/2019] [Indexed: 06/10/2023]
Abstract
Perfluorooctane sulfonamide (FOSA) is known as a key intermediate of perfluorooctane sulfonic acid (PFOS) precursors, which can be frequently detected in the environment and biota. FOSA could be bioaccumulated in earthworms from soil, but the contributions of enzymes and gut microbes involved in the biotransformation of FOSA in earthworms have not been identified. Therefore, the effects of enzyme inhibitors and intestinal microflora on biotransformation of FOSA in earthworms were investigated in the present study. FOSA was biotransformed to form PFOS by earthworms obtained from in vivo and in vitro tests. The addition of FOSA had significantly positive effects on cytolchrome P450 (CYP450) and glutathione-s-transferase (GST) activities, suggesting CYP450 and GST are likely involved in the enzymatic transformation. In addition, both 1-Aminobenzotriazole (ABT) and ezatiostat hydrochloride (TLK199), which were selected to inhibit the CYP and GST enzymes, respectively, demonstrated inhibition effects on biotransformation of FOSA in earthworms with a dose-dependent relationship. However, the concentrations of FOSA weren't changed by the bacteria isolated from worm gut, suggesting that gut bacteria did not contribute to FOSA biotransformation in earthworms. The results of this study confirm that the transformation of FOSA in earthworms is mediated mainly by enzymes rather than by gut microbes.
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Affiliation(s)
- Shuyan Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China.
| | - Bohui Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Zhe Zhong
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Tianqi Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Tiankun Liang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Jingjing Zhan
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE),; School of Ocean Science and Technology, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
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14
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Zhao S, Liang T, Zhu L, Yang L, Liu T, Fu J, Wang B, Zhan J, Liu L. Fate of 6:2 fluorotelomer sulfonic acid in pumpkin (Cucurbita maxima L.) based on hydroponic culture: Uptake, translocation and biotransformation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:804-812. [PMID: 31200206 DOI: 10.1016/j.envpol.2019.06.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/27/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
6:2 fluorotelomer sulfonic acid (6:2 FTSA) is currently used as an alternative to perfluorooctanesulfonate (PFOS) and is widely detected in the environment. The uptake, translocation and biotransformation of 6:2 FTSA in pumpkin (Cucurbita maxima L.) were investigated by hydroponic exposure for the first time. The root concentration factor (RCF) of 6:2 FTSA was 2.6-24.2 times as high as those of perfluoroalkyl acids (PFAAs) of the same or much shorter carbon chain length, demonstrating much higher bioaccumulative ability of 6:2 FTSA in pumpkin roots. The translocation capability of 6:2 FTSA from root to shoot depended on its hydrophobicity. Six terminal perfluorocarboxylic acid (PFCA) metabolites, including perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), perfluorobutanoic acid (PFBA), perfluoropropionic acid (PFPrA) and trifluoroacetic acid (TFA) were found in pumpkin roots and shoots. PFHpA was the primary metabolite in roots, while PFBA was the major product in shoots. 1-aminobenzotriazole (ABT), a cytochromes P450 (CYPs) suicide inhibitor, could decrease the concentrations of PFCA products with dose-dependent relationships in pumpkin tissues, implying the role of CYP enzymes involved in plant biotransformation of 6:2 FTSA. This study indicated that the application of 6:2 FTSA can lead to the occurrence of PFCAs (C2-C7) in plants.
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Affiliation(s)
- Shuyan Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China.
| | - Tiankun Liang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, PR China
| | - Liping Yang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, PR China
| | - Tianqi Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Jia Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Bohui Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Jingjing Zhan
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Lifen Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
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15
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Wang X, Zhou C, He B, Kong B, Wei L, Wang R, Lin J, Shao Y, Zhu J, Jin Y, Fu Z. 8:2 Fluorotelomer alcohol causes G1 cell cycle arrest and blocks granulocytic differentiation in HL-60 cells. ENVIRONMENTAL TOXICOLOGY 2019; 34:666-673. [PMID: 30794351 DOI: 10.1002/tox.22733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/21/2019] [Accepted: 01/27/2019] [Indexed: 06/09/2023]
Abstract
Fluorotelomer alcohols (FTOHs) are fluorinated intermediates used in manufacturing specialty polymer and surfactants, with 8:2 FTOH the homologue of largest production. FTOHs were found to pose acute toxicity, hepatotoxicity, nephrotoxicity, developmental toxicity and endocrine-disrupting risks, whereas research regarding immunotoxicity and its underlying mechanism, especially on specific immune cells is limited. Here, we investigated the immunotoxicity of 8:2 FTOH on immature immune cells in an in vitro system. We observed that exposure of HL-60 cells, a human promyelocytic leukemic cell line, to 8:2 FTOH reduced cell viability in a dose- and time-dependent manner. In addition, 8:2 FTOH exposure caused G1 cell cycle arrest in HL-60 cells, while it showed no effect on apoptosis. Exposure to 8:2 FTOH inhibited the mRNA expression of cell cycle-related genes, including CCNA1, CCNA2, CCND1, and CCNE2. Moreover, exposure to 8:2 FTOH inhibited the mRNA expression of granulocytic differentiation-related genes of CD11b, CSF3R, PU.1, and C/EPBε in HL-60 cells . Furthermore, 8:2 FTOH exhibited no effect on intracellular ROS level, while hydralazine hydrochloride (Hyd), one reactive carbonyl species (RCS) scavenger, partially blocked 8:2 FTOH-caused cytotoxicity in HL-60 cells. Overall, the results obtained in the study show that 8:2 FTOH poses immunotoxicity in immature immune cells and RCS may partially underline its mechanism.
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Affiliation(s)
- Xia Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Chenqian Zhou
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Bingnan He
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Baida Kong
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Lai Wei
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Rong Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jiajia Lin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yiyan Shao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Jianbo Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Yuanxiang Jin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, China
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16
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Kong B, Wang X, He B, Wei L, Zhu J, Jin Y, Fu Z. 8:2 fluorotelomer alcohol inhibited proliferation and disturbed the expression of pro-inflammatory cytokines and antigen-presenting genes in murine macrophages. CHEMOSPHERE 2019; 219:1052-1060. [PMID: 30558807 DOI: 10.1016/j.chemosphere.2018.12.091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/23/2018] [Accepted: 12/11/2018] [Indexed: 06/09/2023]
Abstract
Fluorotelomer alcohols (FTOHs, F(CF2)nCH2CH2OH) are members of per- and polyfluoroalkyl substances (PFASs) and are increasingly used in surfactant and polymer industries. FTOHs pose hepatotoxicity, nephrotoxicity and endocrine-disrupting risks. Nevertheless, there is limited research on the immunotoxic effects of FTOHs. In this study, we examined the immunotoxicity of 8:2 FTOH (n = 8) on murine macrophage cell line RAW 264.7. The results showed that 8:2 FTOH exposure reduced cell viability in dose- and time-dependent manners, inhibited cell proliferation and caused cell cycle arrest. Exposure to 8:2 FTOH downregulated the mRNA expression of some cell cycle-related genes, including Cdk4, Ccnd1, Ccne1, and p53, but also upregulated the mRNA expression of other cell cycle related genes, including Ccna2, p21, and p27. Additionally, exposure to 8:2 FTOH under unstimulated and LPS-stimulated conditions downregulated the mRNA expression of pro-inflammatory genes, including Il1b, Il6, Cxcl1, and Tnfa, and secreted levels of IL-6 and TNF-α. Treatment with 8:2 FTOH upregulated the mRNA expression of antigen-presenting-related genes, including H2-K1, H2-Ka, Cd80, and Cd86. The abovementioned immunotoxic effects caused by 8:2 FTOH in RAW 264.7 cells were partially or completely blocked by co-treatment with hydralazine hydrochloride (Hyd), a reactive carbonyl species (RCS) scavenger. However, exposure to 8:2 FTOH did not exhibit any effects on intracellular reactive oxygen species (ROS) level with or without LPS stimulation. Taken together, these results suggest that 8:2 FTOH may have immunotoxic effects on macrophages and RCS may underlie the responsible mechanism. The present study aids in understanding the health risks caused by FTOHs.
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Affiliation(s)
- Baida Kong
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xia Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Bingnan He
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Lai Wei
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jianbo Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yuanxiang Jin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
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17
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Rewerts JN, Morré JT, Massey Simonich SL, Field JA. In-Vial Extraction Large Volume Gas Chromatography Mass Spectrometry for Analysis of Volatile PFASs on Papers and Textiles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10609-10616. [PMID: 30148348 DOI: 10.1021/acs.est.8b04304] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Volatile per- and polyfluorinated alkyl substances (PFASs) are found in consumer goods that contribute to human exposure to PFASs. Volatile PFAS precursors transform to perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) in both humans and the environment. Established methods for volatile PFASs in consumer goods exist, but higher sample throughput and greener sample preparation methods are needed to minimize analyte loss, while maintaining sensitivity. New analytical methodology was developed where a 1.5 × 1.5 cm piece of paper or textile is placed into an autosampler vial with solvent and mass-labeled internal standards, sonicated for 30 min, and directly injected without removal of material from the autosampler vial. Large volume injection (20 μL) gas chromatography mass spectrometry was applied for the quantification for 21 individual PFASs from five classes: fluorotelomer alcohols (FTOHs), fluorinated sulfonamides (N-MeFASA, N-EtFASA), and fluorinated sulfonamidoethanols (N-MeFASE, N-EtFASE). Nontargeted analysis revealed additional C2-C7 homologues of N-MeFASE and N-EtFASE, which accounted for 14-18% of the total volatile PFASs on three textiles. Overlooking short-chain (≤C7) N-MeFASE, N-EtFASE, and long-chained (10:2-14:2) FTOHs on older textiles from the 1980s leads to an underestimation of human and environmental exposure to volatile PFAS.
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Affiliation(s)
- Justin N Rewerts
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Jeffrey T Morré
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Staci L Massey Simonich
- Department of Environmental and Molecular Toxicology , Oregon State University , 1007 ALS Bldg., 2750 Campus Way , Corvallis , Oregon 97331 , United States
| | - Jennifer A Field
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
- Department of Environmental and Molecular Toxicology , Oregon State University , 1007 ALS Bldg., 2750 Campus Way , Corvallis , Oregon 97331 , United States
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Claesson A, Minidis A. Systematic Approach to Organizing Structural Alerts for Reactive Metabolite Formation from Potential Drugs. Chem Res Toxicol 2018; 31:389-411. [DOI: 10.1021/acs.chemrestox.8b00046] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Alf Claesson
- Awametox AB, Lilldalsvägen 17 A, SE-14461 Rönninge, Sweden
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19
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Kabadi SV, Fisher J, Aungst J, Rice P. Internal exposure-based pharmacokinetic evaluation of potential for biopersistence of 6:2 fluorotelomer alcohol (FTOH) and its metabolites. Food Chem Toxicol 2018; 112:375-382. [PMID: 29331735 DOI: 10.1016/j.fct.2018.01.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 11/26/2022]
Abstract
Polyfluorinated compounds (PFCs) are authorized for use as greaseproofing agents in food contact paper. As C8-PFCs (8-carbons) are known to accumulate in tissues, shorter-chain C6-PFCs (6-carbons) have replaced C8-PFCs in many food contact applications. However, the potential of C6-PFCs for human biopersistence has not been fully evaluated. For the first time, we provide internal exposure estimates to key metabolites of 6:2 fluorotelomer alcohol (6:2 FTOH), a monomeric component of C6-PFCs, to extend our understanding of exposure beyond estimates of external exposure. Pharmacokinetic data from published rat and human studies on 6:2 FTOH were used to estimate clearance and area under the curve (AUC) for its metabolites: 5:3 fluorotelomer carboxylic acid (5:3 A), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA). Internal exposure to 5:3 A was the highest of evaluated metabolites across species and it had the slowest clearance. Additionally, 5:3 A clearance decreased with increasing 6:2 FTOH exposure. Our analysis provides insight into association of increased internal 5:3 A exposure with high biopersistence potential of 6:2 FTOH. Our results identify 5:3 A as an important biomarker of internal 6:2 FTOH exposure for use in biomonitoring studies, and are potentially useful for toxicological assessment of chronic dietary 6:2 FTOH exposure.
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Affiliation(s)
- Shruti V Kabadi
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States.
| | - Jeffrey Fisher
- FDA/NCTR, 3900 NCTR Road, Jefferson, AR 72079, United States
| | - Jason Aungst
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States
| | - Penelope Rice
- FDA/CFSAN/OFAS/DFCN, 5001 Campus Drive, HFS 275, College Park, MD 20740, United States
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20
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Joudan S, Yeung LWY, Mabury SA. Biological Cleavage of the C–P Bond in Perfluoroalkyl Phosphinic Acids in Male Sprague-Dawley Rats and the Formation of Persistent and Reactive Metabolites. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:117001. [PMID: 29135439 PMCID: PMC5947941 DOI: 10.1289/ehp1841] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 05/27/2023]
Abstract
BACKGROUND Perfluoroalkyl phosphinic acids (PFPiAs) have been detected in humans, wildlife, and various environmental matrices. These compounds have been used with perfluoroalkyl phosphonic acids (PFPAs) as surfactants in consumer products and as nonfoaming additives in pesticide formulations. Unlike the structurally related perfluoroalkyl sulfonic and carboxylic acids, little is known about the biological fate of PFPiAs. OBJECTIVES We determined the biotransformation products of PFPiAs and some pharmacokinetic parameters in a rat model. METHODS Male Sprague-Dawley rats received an oral gavage dose of either C6/C8PFPiA, C8/C8PFPiA, or C8PFPA. Blood was sampled over time, and livers were harvested upon sacrifice. Analytes were quantified using ultra-high-performance liquid chromatography-tandem mass spectrometry or gas chromatography-mass spectrometry. RESULTS PFPiAs were metabolized to the corresponding PFPAs and 1H-perfluoroalkanes (1H-PFAs), with 70% and 75% biotransformation 2 wk after a single bolus dose for C6/C8PFPiA and C8/C8PFPiA, respectively. This is the first reported cleavage of a C-P bond in mammals, and the first attempt, with a single-dose exposure, to characterize the degradation of any perfluoroalkyl acid. Elimination half-lives were 1.9±0.5 and 2.8±0.8 days for C6/C8PFPiA and C8/C8PFPiA, respectively, and 0.95±0.17 days for C8PFPA. Although elimination half-lives were not determined for 1H-PFAs, concentrations were higher than the corresponding PFPAs 48 h after rats were dosed with PFPiAs, suggestive of slower elimination. CONCLUSIONS PFPiAs were metabolized in Sprague-Dawley rats to form persistent PFPAs as well as 1H-PFAs, which contain a labile hydrogen that may undergo further metabolism. These results in rats produced preliminary findings of the pharmacokinetics and metabolism of PFPiAs, which should be further investigated in humans. If there is a parallel between the disposition of these chemicals in humans and rats, then humans with detectable amounts of PFPiAs in their blood may be undergoing continuous exposure. https://doi.org/10.1289/EHP1841.
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Affiliation(s)
- Shira Joudan
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Leo W Y Yeung
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Scott A Mabury
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
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Zhao S, Zhu L. Uptake and metabolism of 10:2 fluorotelomer alcohol in soil-earthworm (Eisenia fetida) and soil-wheat (Triticum aestivum L.) systems. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 220:124-131. [PMID: 27639617 DOI: 10.1016/j.envpol.2016.09.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/09/2016] [Accepted: 09/11/2016] [Indexed: 05/27/2023]
Abstract
The behavior of 10:2 fluorotelomer alcohol (10:2 FTOH) in the systems of soil-earthworm (Eisenia fetida), soil-wheat (Triticum aestivum L.) and soil-earthworm-wheat, including degradation in soil, uptake and metabolism in wheat and earthworms were investigated. Several perfluorocarboxylic acids (PFCAs) as degradation products of 10:2 FTOH were identified in the soil, plant and earthworms. 10:2 FTOH could be biodegraded to perfluorooctanoate (PFOA), perfluorononanate (PFNA) and perfluorodecanoate (PFDA) in soil in the absence or presence of wheat/earthworms, and PFDA was the predominant metabolite. Accumulation of initial 10:2 FTOH and its metabolites were observed in the wheat and earthworms, suggesting that 10:2 FTOH could be bioaccumulated in wheat and earthworms and biotransformed to the highly stable PFCAs. Perfluoropentanoic acid (PFPeA), perfluorohexanoic (PFHxA) and PFDA were detected in wheat root, while PFDA and perfluoroundecanoic acid (PFUnDA) were detected in shoot. PFNA and PFDA were determined in earthworms and the concentration of PFDA was much higher. The presence of earthworms and/or plant stimulated the microbial degradation of 10:2 FTOH in soil. The results supplied important evidence that degradation of 10:2 FTOH was an important potential source of PFCAs in the environment and in biota.
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Affiliation(s)
- Shuyan Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Food and Environment, Dalian University of Technology, Panjin, Liaoning, 124221, PR China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, PR China.
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22
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Is there a human health risk associated with indirect exposure to perfluoroalkyl carboxylates (PFCAs)? Toxicology 2017; 375:28-36. [DOI: 10.1016/j.tox.2016.11.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/07/2016] [Accepted: 11/14/2016] [Indexed: 11/19/2022]
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23
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Zhang H, Wen B, Hu X, Wu Y, Pan Y, Huang H, Liu L, Zhang S. Uptake, Translocation, and Metabolism of 8:2 Fluorotelomer Alcohol in Soybean (Glycine max L. Merrill). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:13309-13317. [PMID: 27993068 DOI: 10.1021/acs.est.6b03734] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Biotransformation of fluorotelomer alcohols (FTOHs) is widely considered as an additional source of perfluorocarboxylic acids (PFCAs) in environmental biota. Compared with the extensive studies conducted in animals and microbes, biotransformation pathways of FTOHs in plants are still unclear. In this study, a hydroponic experiment was conducted to investigate the uptake, translocation and metabolism of 8:2 FTOH in soybean (Glycine max L. Merrill) over 144 h. 8:2 FTOH and its metabolites were found in all parts of soybean plants. At the end of the exposure, 7:3 FTCA [F(CF2)7CH2CH2COOH] was the primary metabolite in roots and stems, while PFOA [F(CF2)7COOH] was predominant in leaves. PFOA and 7:3 FTCA in the soybean-solution system accounted for 6.01 and 5.57 mol % of the initially applied 8:2 FTOH, respectively. Low levels of PFHpA [F(CF2)6COOH] and PFHxA [F(CF2)5COOH] in solutions and soybean roots resulted from microbial metabolism and plant root uptake. Glutathione-conjugated metabolites in soybean tissues were also identified. The activities of alcohol dehydrogenase, aldehyde dehydrogenase, and glutathione S-transferase in soybean roots increased during the exposure, suggesting their roles in 8:2 FTOH metabolism in soybean. This study provides important information for a better understanding of the uptake and metabolism of FTOHs and fluorotelomer-based compounds in plants.
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Affiliation(s)
- Hongna Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Bei Wen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
| | - Xiaoyu Hu
- Beijing Center for Disease Prevention and Control, Beijing 100020, China
| | - Yali Wu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Ying Pan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
- University of Chinese Academy of Sciences , Beijing 100049, China
| | - Honglin Huang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
| | - Liu Liu
- Beijing Center for Disease Prevention and Control, Beijing 100020, China
| | - Shuzhen Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing 100085, China
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24
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Dagnino S, Strynar MJ, McMahen RL, Lau CS, Ball C, Garantziotis S, Webster TF, McClean MD, Lindstrom AB. Identification of Biomarkers of Exposure to FTOHs and PAPs in Humans Using a Targeted and Nontargeted Analysis Approach. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:10216-25. [PMID: 27477586 PMCID: PMC5942555 DOI: 10.1021/acs.est.6b01170] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Although historic perfluorinated compounds are currently under scrutiny and growing regulatory control in the world, little is known about human exposure to other polyfluorinated compounds presently in use. Fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphate esters (PAPs) are known to degrade to terminal perfluorinated acids and toxic reactive intermediates through metabolic pathways. Therefore, it is important to characterize their human exposure by the identification of unique biomarkers. With the use of liquid chromatography-mass spectrometry-time-of-flight analysis (LC-MS-TOF), we developed a workflow for the identification of metabolites for the 8:2 FTOH and 8:2 diPAP. Analysis of serum and urine of dosed rats indicated the 8:2 FTOH-sulfate and the 8:2 diPAP as potential biomarkers. These compounds, as well as 25 other fluorinated compounds and metabolites, were analyzed in human serum and urine samples from the general population (n = 100) and office workers (n = 30). The 8:2 FTOH-sulfate was measured for the first time in human samples in 5 to 10% of the serum samples, ranging from 50 to 80 pg/mL. The 8:2 diPAP was measured in 58% of the samples, ranging from 100 to 800 pg/mL. This study indicates the FTOH-sulfate conjugate as a biomarker of exposure to FTOHs and PAPs in humans.
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Affiliation(s)
- Sonia Dagnino
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
- Oak Ridge Associated Universities, ORISE Program, Oak Ridge, Tennessee 37831, United States
- Corresponding Authors: S.G. phone: + 44-7480 127942; ; M.S. phone: 919-541-3706;
| | - Mark J. Strynar
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
- Corresponding Authors: S.G. phone: + 44-7480 127942; ; M.S. phone: 919-541-3706;
| | - Rebecca L. McMahen
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
- Oak Ridge Associated Universities, ORISE Program, Oak Ridge, Tennessee 37831, United States
| | - Christopher S. Lau
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
| | - Carol Ball
- Agilent Technologies, Inc., 13000 Weston Parkway, Cary, North Carolina 27510, United States
| | - Stavros Garantziotis
- Clinical Research Program and Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, United States
| | - Thomas F. Webster
- Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, T4W, Boston, Massachusetts 02118, United States
| | - Michael D. McClean
- Department of Environmental Health, Boston University School of Public Health, 715 Albany Street, T4W, Boston, Massachusetts 02118, United States
| | - Andrew B. Lindstrom
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, United States
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25
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Li ZM, Guo LH, Ren XM. Biotransformation of 8:2 fluorotelomer alcohol by recombinant human cytochrome P450s, human liver microsomes and human liver cytosol. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2016; 18:538-46. [PMID: 27152847 DOI: 10.1039/c6em00071a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Biotransformation of 8:2 fluorotelomer alcohol (8:2 FTOH) can form potentially more toxic metabolites. However, the responsible cytochrome P450 (CYP) isoform(s) and phase II metabolism have not been studied in humans. Here, we characterized the in vitro metabolism of 8:2 FTOH by recombinant human CYPs, human liver microsomes, and human liver cytosol. The results showed that among the 11 isoforms investigated, CYP2C19 was the only enzyme capable of catalyzing 8:2 FTOH with Km and Vmax values of 18.8 μM and 8.52 pmol min(-1) pmol(-1) P450, respectively. The phase I metabolite was identified as 8:2 fluorotelomer aldehyde (8:2 FTAL). HLMs also catalyzed 8:2 FTOH transformation, with the Vmax and intrinsic clearance (CLint) values similar to those of CYP2C19 after the protein content is taken into account. Molecular docking showed that the hydroxyl group of 8:2 FTOH accesses the heme iron-oxo of CYP2C19 in an energetically favored orientation. 8:2 FTOH was also transformed by phase II enzymes to form O-glucuronide and O-sulfate conjugates. The CLint values follow the order of sulfation > oxidation > glucuronidation, suggesting that conjugation is the major metabolic pathway, which explains the low yield of perfluoroalkyl acids (PFCAs). These results provide new insight into fluorotelomer alcohol biotransformation and indirect human exposure to PFCAs.
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Affiliation(s)
- Zhong-Min Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P. O. Box 2871, 18 Shuangqing Road, Beijing 100085, China.
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26
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Wang X, Sun M, New C, Nam S, Blackaby WP, Hodges AJ, Nash D, Matteucci M, Lyssikatos JP, Fan PW, Tay S, Chang JH. Probing Mechanisms of CYP3A Time-Dependent Inhibition Using a Truncated Model System. ACS Med Chem Lett 2015; 6:925-9. [PMID: 26288695 DOI: 10.1021/acsmedchemlett.5b00191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 07/12/2015] [Indexed: 12/17/2022] Open
Abstract
Time-dependent inhibition (TDI) of cytochrome P450 (CYP) enzymes may incur serious undesirable drug-drug interactions and in rare cases drug-induced idiosyncratic toxicity. The reactive metabolites are often generated through multiple sequential biotransformations and form adducts with CYP enzymes to inactivate their function. The complexity of these processes makes addressing TDI liability very challenging. Strategies to mitigate TDI are therefore highly valuable in discovering safe therapies to benefit patients. In this Letter, we disclose our simplified approach toward addressing CYP3A TDI liabilities, guided by metabolic mechanism hypotheses. By adding a methyl group onto the α carbon of a basic amine, TDI activities of both the truncated and full molecules (7a and 11) were completely eliminated. We propose that truncated molecules, albeit with caveats, may be used as surrogates for full molecules to investigate TDI.
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Affiliation(s)
- Xiaojing Wang
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Minghua Sun
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Connie New
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Spencer Nam
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Wesley P. Blackaby
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Alastair J. Hodges
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - David Nash
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Mizio Matteucci
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Joseph P. Lyssikatos
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Peter W. Fan
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Suzanne Tay
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
| | - Jae H. Chang
- Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States
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27
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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] [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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28
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Rand AA, Mabury SA. Protein binding associated with exposure to fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphate esters (PAPs) in rats. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2421-9. [PMID: 24460105 DOI: 10.1021/es404390x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The biotransformation of fluorotelomer-based compounds such as fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphate esters (PAPs) are sources of exposure to perfluorinated carboxylates (PFCAs), leading in part to the observation of significant concentrations of PFCAs in human blood. The biotransformation of FTOHs and PAPs yield intermediate metabolites that have been observed to covalently modify proteins. In the current investigation, the extent of covalent protein binding in Sprague-Dawley rats upon exposure to 8:2 FTOH and the 6:2 polyfluoroalkyl phosphate diester (6:2 diPAP) was quantified. The animals were administered a single dose of 8:2 FTOH or 6:2 diPAP at 100 mg/kg by oral gavage to monitor biotransformation and extent of protein binding within the liver, kidney, and plasma. In the 8:2 FTOH-dosed animals, perfluorooctanoate (PFOA) was produced as the primary PFCA, at 623.13 ± 59.3, 459.5 ± 171.8, and 397.3 ± 133.0 ng/g in the plasma, liver, and kidney, respectively. For the animals exposed to 6:2 diPAPs, perfluorohexanoate (PFHxA) was the primary PFCA produced, with maximum concentrations of 57.4 ± 6.5, 9.0 ± 1.2, and 25.3 ± 1.2 ng/g in the plasma, liver, and kidney, respectively. Protein binding was observed in the plasma, liver, and kidney after 8:2 FTOH and 6:2 diPAP exposure, with the most significant binding occurring in the liver (>100 nmol/g protein). This is the first study to link the exposure and in vivo biotransformation of fluorotelomer-based compounds to covalent protein binding.
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Affiliation(s)
- Amy A Rand
- University of Toronto , Department of Chemistry, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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29
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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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Rand AA, Mabury SA. Covalent binding of fluorotelomer unsaturated aldehydes (FTUALs) and carboxylic acids (FTUCAs) to proteins. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1655-63. [PMID: 23256684 DOI: 10.1021/es303760u] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fluorotelomer unsaturated carboxylic acids and aldehydes (FTUCAs and FTUALs) are intermediate compounds that form from the biotransformation of fluorotelomer-based compounds. Previous evidence that FTUCAs and FTUALs bind to biological nucleophiles has indicated that protein binding might give rise to toxicity resulting from protein function disruption. The current study assesses the reactivity of FTUALs and FTUCAs by probing the covalent interactions of FTUALs and FTUCAs with proteins present in rat liver microsomes and bovine blood plasma. The FTUALs exhibited significant levels of protein covalent binding, with binding levels ranging from 20.1 (±2.8)% to 71.3 (±19.5)% in microsomes and 24.0 (±1.5)% to 82.5 (±14.0)% in blood plasma. By contrast, the FTUCAs did not exhibit any apparent covalent binding. Bovine serum albumin (BSA) was extracted and isolated from the plasma after incubation of 8:2 FTUAL (5-100 μM). Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the stoichiometry of 8:2 FTUAL covalently bound to BSA; three measurable FTUAL adducts were formed with BSA. To compare the percent binding results from the FTUAL microsome incubation experiments, 8:2 FTOH was incubated in microsomes to determine the protein binding associated with the biotransformation of 8:2 FTOH. Results from this study showed that the biotransformation of 8:2 FTOH yielded 26.1 (±3.0)% binding, and was statistically similar to the percent binding associated with 8:2 FTUAL exposure (p > 0.05), indicating that the binding of 8:2 FTUAL to proteins might be a primary fate in the biotransformation of 8:2 FTOH.
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Affiliation(s)
- Amy A Rand
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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31
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Nilsson H, Kärrman A, Rotander A, van Bavel B, Lindström G, Westberg H. Biotransformation of fluorotelomer compound to perfluorocarboxylates in humans. ENVIRONMENT INTERNATIONAL 2013; 51:8-12. [PMID: 23138016 DOI: 10.1016/j.envint.2012.09.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 08/14/2012] [Accepted: 09/04/2012] [Indexed: 05/03/2023]
Abstract
Levels of perfluorocarboxylates (PFCAs) in biological compartments have been known for some time but their transport routes and distribution patterns are not properly elucidated. The opinions diverge whether the exposure of the general population occurs indirect through precursors or direct via PFCAs. Previous results showed that ski wax technicians are exposed to levels up to 92 000 ng/m(3) of 8:2 fluorotelomer alcohol (FTOH) via air and have elevated blood levels of PFCAs. Blood samples were collected in 2007-2011 and analyzed for C(4)-C(18) PFCAs, 6:2, 8:2 and 10:2 unsaturated fluorotelomer acids (FTUCAs) and 3:3, 5:3 and 7:3 fluorotelomer acids (FTCAs) using UPLC-MS/MS. Perfluorooctanoic acid (PFOA) was detected in levels ranging from 1.90 to 628 ng/mL whole blood (wb). Metabolic intermediates 5:3 and 7:3 FTCA were detected in all samples at levels up to 6.1 and 3.9 ng/mL wb. 6:2, 8:2 and 10:2 FTUCAs showed maximum levels of 0.07, 0.64 and 0.11 ng/mL wb. Also, for the first time levels of PFHxDA and PFOcDA were detected in the human blood at mean concentrations up to 4.22 ng/mL wb and 4.25 ng/mL wb respectively. The aim of this study was to determine concentrations of PFCAs and FTOH metabolites in blood from ski wax technicians.
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Affiliation(s)
- Helena Nilsson
- Man-Technology-Environment (MTM) Research Centre, Örebro University, SE-701 82 Örebro, Sweden.
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32
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Rand AA, Mabury SA. In vitro interactions of biological nucleophiles with fluorotelomer unsaturated acids and aldehydes: fate and consequences. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:7398-7406. [PMID: 22582947 DOI: 10.1021/es3008485] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fluorotelomer unsaturated aldehydes and acids (FTUALs and FTUCAs) are intermediate metabolites that form from the biotransformation of fluorotelomer-based chemicals. FTUALs and FTUCAs have been previously suggested to contribute to the toxicity associated with human exposure to fluorotelomer compounds by covalently binding to biological nucleophiles. However, the extent of their reactivity has only been assessed with glutathione. The purpose of the present study was to assess the reactivity of these intermediate metabolites with a series of nucleophilic amino acids and model proteins. In vitro experiments were carried out in an aqueous buffer system to determine the reactivity of nucleophilic amino acids with FTUCAs and FTUALs having varying fluorinated chain lengths. Using (19)F NMR spectroscopy to monitor the disappearance of the FTUCAs and FTUAL signals and the production of a fluoride signal, reaction rate constants were determined under pseudo-first-order conditions. The FTUCAs reacted only with cysteine with the following second order rate constants: 3.63 (± 1.37) × 10(-5) min(-1) mM(-1) (4:2 FTUCA), 1.19 (± 0.91) × 10(-5) min(-1) mM(-1) (6:2 FTUCA), and 4.56 (± 0.94) × 10(-5) min(-1) mM(-1) (8:2 FTUCA). The FTUALs were significantly more reactive than any of the FTUCAs with reactivity decreasing in the following order: cysteine >> histidine > lysine >> arginine. The following second-order rate constants were obtained: 5.7 (± 4.2) × 10(-4) min(-1) mM(-1) (histidine), 4.3 (± 1.4) × 10(-4) min(-1) mM(-1) (lysine), and 1.4 (± 0.73) × 10(-4) min(-1) mM(-1) (arginine). FTUCAs and FTUALs were also reacted with model proteins to assess their potential for forming covalent adducts. Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the stoichiometry of FTUCAs and FTUALs covalently bound to apomyoglobin (ApoMg) and human serum albumin (HSA). FTUCAs were not reactive, whereas two measurable FTUAL adducts were formed with both ApoMg and HSA at each of the FTUAL chain lengths (6:2, 8:2, and 10:2). This is the first study to probe the reactivity of FTUALs and FTUCAs with nucleophiles other than glutathione, further elucidating possible FTUAL and FTUCA fate within biological systems.
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Affiliation(s)
- Amy A Rand
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
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Rand AA, Mabury SA. Assessing the structure-activity relationships of fluorotelomer unsaturated acids and aldehydes with glutathione. Reactivity of glutathione with fluorotelomer unsaturated acids and aldehydes. Cell Biol Toxicol 2012; 28:115-24. [PMID: 22252736 DOI: 10.1007/s10565-012-9211-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 01/03/2012] [Indexed: 11/25/2022]
Abstract
Fluorotelomer alcohols (FTOHs) have been shown to degrade via abiotic and biotic mechanisms to perfluorocarboxylates (PFCAs) which are environmentally persistent and bioaccumulate in humans and wildlife depending on their chain length. Fluorotelomer unsaturated aldehydes (FTUALs) and acids (FTUCAs) are intermediate metabolites that form from the degradation of FTOHs. Their potential for toxicity is not yet defined and may be more significant compared to PFCAs. Past studies have shown that these intermediates form adducts with glutathione (GSH). The purpose of this study was to further assess the reactivity of these intermediate compounds. In vitro experiments were carried out in an aqueous buffer system (pH 7.4) where FTUCAs and FTUALs of varying chain lengths were reacted with GSH. To quantify the reactivity of FTUCAs and FTUALs, unreacted free GSH was derivatized with 5,5'-dithiobis(2-nitrobenzoic acid), its absorbance measured at 412 nm, and the percentage of unconjugated free GSH evaluated over time. EC50 values were obtained for the reactions of GSH with acrolein and methyl methacrylate to assess the accuracy of the method, as well as for acrylic acid, FTUCAs, and FTUALs. The results of this study indicated that α,β-unsaturated aldehydes are comparatively the most reactive and reaction with GSH may be influenced by the length of the fluorinated tail. This is the first study to examine the relationship of FTUCAs and FTUALs with biological nucleophiles by quantifying their intrinsic reactivity.
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Affiliation(s)
- Amy A Rand
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
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Fraser AJ, Webster TF, Watkins DJ, Nelson JW, Stapleton HM, Calafat AM, Kato K, Shoeib M, Vieira VM, McClean MD. Polyfluorinated compounds in serum linked to indoor air in office environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:1209-15. [PMID: 22148395 PMCID: PMC3262923 DOI: 10.1021/es2038257] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We aimed to investigate the role of indoor office air on exposure to polyfluorinated compounds (PFCs) among office workers. Week-long, active air sampling was conducted during the winter of 2009 in 31 offices in Boston, MA. Air samples were analyzed for fluorotelomer alcohols (FTOHs), sulfonamides (FOSAs), and sulfonamidoethanols (FOSEs). Serum was collected from each participant (n = 31) and analyzed for 12 PFCs including PFOA and PFOS. In air, FTOHs were present in the highest concentrations, particularly 8:2-FTOH (GM = 9920 pg/m(3)). FTOHs varied significantly by building with the highest levels observed in a newly constructed building. PFOA in serum was significantly correlated with air levels of 6:2-FTOH (r = 0.43), 8:2-FTOH (r = 0.60), and 10:2-FTOH (r = 0.62). Collectively, FTOHs in air significantly predicted PFOA in serum (p < 0.001) and explained approximately 36% of the variation in serum PFOA concentrations. PFOS in serum was not associated with air levels of FOSAs/FOSEs. In conclusion, FTOH concentrations in office air significantly predict serum PFOA concentrations in office workers. Variation in PFC air concentrations by building is likely due to differences in the number, type, and age of potential sources such as carpeting, furniture, and/or paint.
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Affiliation(s)
- Alicia J Fraser
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
| | - Thomas F Webster
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
| | - Deborah J Watkins
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
| | - Jessica W Nelson
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
| | - Heather M Stapleton
- Duke University, Nicholas School of the Environment, 450 Research Dr, Durham, NC 27708
| | - Antonia M Calafat
- Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy NE, Mailstop F53, Atlanta, GA 30341
| | - Kayoko Kato
- Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Hwy NE, Mailstop F53, Atlanta, GA 30341
| | - Mahiba Shoeib
- Environment Canada, Science and Technology Branch, 4905 Dufferin Street, Toronto, Ontario, M3H 5T4
| | - Verónica M Vieira
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
| | - Michael D McClean
- Boston University School of Public Health, 715 Albany St, T4W, Boston, MA 02118
- Corresponding author: Michael D. McClean, BUSPH Department of Environmental Health, 715 Albany Street, T4W, Boston, MA 02118, , Phone: 617-638-7755, Fax: 617-638-4857
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D'eon JC, Mabury SA. Is indirect exposure a significant contributor to the burden of perfluorinated acids observed in humans? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:7974-84. [PMID: 21630688 DOI: 10.1021/es200171y] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In comparison to other persistent organic pollutants, human fluorochemical contamination is relatively complicated. This complication arises at least in part from a disparity between the chemicals used commercially and those measured in the environment and humans. Commercial fluorochemical products are dominated by fluorinated polymers used in textile or carpet applications, or fluorosurfactants used in applications ranging from personal care products, leveling and wetting agents, to greaseproofing food-contact materials. Investigations into environmental and human fluorochemical contamination have focused on perfluorinated acids (PFAs), either the perfluorinated carboxylates (PFCAs) or sulfonates (PFSAs). In this review we will present an overview of data related to human fluorochemical exposure including a discussion of fluorochemical production, concentrations in exposure media, biotransformation processes producing PFAs, and trends in human sera. These data will be presented in the context of how they can inform sources of human PFA contamination, specifically whether the contamination results from direct PFA exposure or indirect exposure via the biotransformation of commercial fluorochemicals or their residuals. Concentrations of both perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) began to decrease in human sera around the year 2000, a change that mirrored the 2000-2002 phase-out of perfluorooctane sulfonyl fluoride (POSF) production. These temporal trends suggest exposure to current-use POSF-based materials was a significant source of PFOA and PFOS exposure prior to 2000. Relatively slow PFOA elimination and increasing concentrations of the C9 and C10 PFCAs in human sera suggest continued PFCA exposure, without similar exposure to PFOS, which is consistent with indirect exposure via the biotransformation of fluorotelomer-based materials. Conversely, human exposure models have suggested direct exposure to PFAs present in food items is the major source of human contamination. The data set presented here cannot unequivocally delineate between direct and indirect human exposure, however temporal trends in human sera and exposure media are consistent with indirect exposure representing a significant portion of observed human PFA contamination.
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Affiliation(s)
- Jessica C D'eon
- Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6 Canada
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Abstract
Investigations on diverse aspects of fluoro-organic compounds have rapidly increased during the past decades. Because natural sources of fluoro-organic compounds are extremely rare, the industrial synthesis of fluorinated organic compounds and production of fluorinated natural product derivatives have greatly expanded in recent years because of their increasing importance in the agrochemical and pharmaceutical industries. Due to structural complexity or instability, synthetic modification is often not possible, and various biofluorination strategies have been developed in recent years for applications in the anti-cancer, anti-viral and anti-infection fields. Despite the industrial importance of fluorinated compounds, there have been serious concerns worldwide over the levels and synthetic routes of certain fluorinated organic compounds, in particular perfluorinated chemicals (PFCs). PFCs are emerging and recalcitrant pollutants which are widely distributed in the environment and have been detected in humans and wildlife globally. PFCs have been demonstrated to be potentially carcinogenic, adversely affect the neuroendocrine and immune systems, and produce neurotoxicity, heptatotoxicity and endocrine disrupting effects in vertebrate animals. Here, we provide an overview of recent advances in our understanding of the biology of various fluoro-organic compounds and perspectives for new enzymes and metabolic pathways for bioremediation of these chemicals.
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Affiliation(s)
- Xiao-Jian Zhang
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong
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Butt CM, Muir DCG, Mabury SA. Biotransformation of the 8:2 fluorotelomer acrylate in rainbow trout. 1. In vivo dietary exposure. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:2726-2735. [PMID: 20836063 DOI: 10.1002/etc.349] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/21/2010] [Accepted: 05/13/2010] [Indexed: 05/29/2023]
Abstract
The bioaccumulation and biotransformation of the 8:2 fluorotelomer acrylate (C(8) F(17) CH(2) CH(2) OC(O)CH = CH(2) , 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.
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Affiliation(s)
- Craig M Butt
- Department of Chemistry, University of Toronto, 80 St George Street, Toronto, Ontario M5S 3H6, Canada
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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: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [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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Kinetics of 8-2 fluorotelomer alcohol and its metabolites, and liver glutathione status following daily oral dosing for 45 days in male and female rats. Chem Biol Interact 2009; 180:281-95. [DOI: 10.1016/j.cbi.2009.03.015] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 03/16/2009] [Accepted: 03/18/2009] [Indexed: 11/23/2022]
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D'Eon JC, Crozier PW, Furdui VI, Reiner EJ, Libelo EL, Mabury SA. Observation of a commercial fluorinated material, the polyfluoroalkyl phosphoric acid diesters, in human sera, wastewater treatment plant sludge, and paper fibers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:4589-4594. [PMID: 19603681 DOI: 10.1021/es900100d] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sources of human exposure to perfluorinated carboxylic acids (PFCAs) are not well-characterized. Polyfluoroalkyl phosphoric acids (PAPs) are fluorinated surfactants used in human food contact paper products. PAPs can migrate into food and food simulants, and their bioavailability and biotransformation into PFCAs has been demonstrated using a rat model. To characterize human exposure to PAP materials, we analyzed pooled human sera samples collected in 2004 and 2005 (n = 10) and 2008 (n = 10) from the midwestern United States for the 4:2 through 10:2 PAP diesters (diPAPs). The 2004 and 2005 sera samples contained 4.5 microg/L total diPAPs, with the 6:2 diPAP dominating the congener profile at 1.9 +/- 0.4 microg/L DiPAP concentrations observed in the 2004 and 2005 human sera samples were similar to those of the C8 to C11 PFCAs (0.13 +/- 0.01 to 4.2 +/- 0.3 microg/L) monitored in the same samples. 6:2 diPAP was also consistently observed in the 2008 human sera samples at a mean concentration of 0.63 +/- 0.13 microg/L As diPAPs have been shown to degrade to PFCAs in vivo, our observation of diPAPs in human sera may be a direct connection between the legacy of human PFCA contamination and PAPs commercial applications. Wastewater treatment plant (WWTP) sludge and paper fibers were analyzed for diPAPs as a proxy for human use and potential exposure to diPAPs. DiPAPs were observed in WWTP sludge at concentrations ranging from 47 +/- 22 to 200 +/- 130 ng/g, a range similar to perfluorooctane sulfonic acid (PFOS) (100 +/- 70 ng/g) and greater than the C8 to C11 PFCAs (1.6 +/- 0.6 to 0.17 +/- 0.10 ng/g) observed in the same samples. DiPAPs were observed in paper fiber extracts at concentrations ranging from 34 +/- 30 to 2200 +/- 400 ng/g. The high diPAP concentrations in WWTP sludge suggest PAP materials may be prevalent in our daily lives.
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Affiliation(s)
- Jessica C D'Eon
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
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