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Jiang W, Zhang Y, Zhu L, Deng J. Serum levels of perfluoroalkyl acids (PFAAs) with isomer analysis and their associations with medical parameters in Chinese pregnant women. ENVIRONMENT INTERNATIONAL 2014; 64:40-47. [PMID: 24361923 DOI: 10.1016/j.envint.2013.12.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/06/2013] [Accepted: 12/02/2013] [Indexed: 05/28/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are a group of chemicals used for many applications and widely present in the environment and humans. In this study, serum levels of PFAAs and isomers of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) were analyzed in 141 Chinese pregnant women. Among all the samples, total PFOS (∑PFOS, mean concentration 7.32ng/mL) was predominant, followed by ∑PFOA (mean 4.78ng/mL) and perfluorodecanoate (PFDA, mean 1.45ng/mL). On average, the proportion of linear PFOS (n-PFOS) was 66.7% of ∑PFOS, which was higher than the general population, implying that maternal women could excrete branched PFOS isomers to the fetus by transplacental transfer. Moreover, the proportion of n-PFOS decreased significantly with the increasing concentration of ∑PFOS in the serum samples (r=-0.342, p<0.001). The mean proportion of n-PFOA in the serum samples was 99.0%, which was much higher than the technical ECF (electrochemical fluorination) products (ca. 70%). The small proportion of branched isomers of PFOA suggests that there is still a source of ECF PFOA in China. Significant correlations (p<0.005) were observed between the concentrations of some PFAAs with certain medical parameters in the pregnant women. For example, the levels of most perfluorinated carboxylic acids (PFCAs) were found to correlate with albumin significantly, which might be a sign of immunotoxicity of these chemicals. The adverse effects of PFAA exposure to pregnant women may increase the health risk of the fetus. Interestingly, not only the PFAA concentrations but also the percentages of PFOS and PFOA isomers were correlated with certain medical parameters. This implies that the compositions of PFOS or PFOA should be considered in human health risk assessment in the future.
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Affiliation(s)
- Weiwei Jiang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Yifeng Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
| | - Lingyan Zhu
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China.
| | - Jimin Deng
- Maternity and Child Care Center, Heping District, Tianjin 300071, PR China
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Zhang Y, Beesoon S, Zhu L, Martin JW. Biomonitoring of perfluoroalkyl acids in human urine and estimates of biological half-life. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:10619-27. [PMID: 23980546 DOI: 10.1021/es401905e] [Citation(s) in RCA: 337] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are persistent and bioaccumulative compounds that have been associated with adverse health outcomes. In human blood, PFAAs exist as both linear and branched isomers, yet for most linear homologues, and for all branched isomers, elimination rates are unknown. Paired blood and urine samples (n = 86) were collected from adults in China. They were analyzed by a sensitive isomer-specific method that permitted the detection of many PFAAs in human urine for the first time. For all PFAAs except perfluoroundecanoate (PFUnA), levels in urine correlated positively with levels in blood. Perfluoroalkyl carboxylates (PFCAs) were excreted more efficiently than perfluoroalkane sulfonates (PFSAs) of the same carbon chain-length. In general, shorter PFCAs were excreted more efficiently than longer ones, but for PFSAs, perfluorooctanesulfonate (PFOS, a C8 compound) was excreted more efficiently than perfluorohexanesulfonate (PFHxS, a C6 compound). Among PFOS and perfluorooctanoate (PFOA) isomers, major branched isomers were more efficiently excreted than the corresponding linear isomer. A one-compartment model was used to estimate the biological elimination half-lives of PFAAs. Among all PFAAs, the estimated arithmetic mean elimination half-lives ranged from 0.5 ± 0.1 years (for one branched PFOA isomer, 5m-PFOA) to 90 ± 11 years (for one branched PFOS isomer, 1m-PFOS). Urinary excretion was the major elimination route for short PFCAs (C ≤ 8), but for longer PFCAs, PFOS and PFHxS, other routes of excretion likely contribute to overall elimination. Urinary concentrations are good biomarkers of the internal dose, and this less invasive strategy can therefore be used in future epidemiological and biomonitoring studies. The very long half-lives of long-chain PFCAs, PFHxS, and PFOS isomers in humans stress the importance of global and domestic exposure mitigation strategies.
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Affiliation(s)
- Yifeng Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University , Tianjin 300071, P.R. China
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53
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The determination of perfluoroalkyl substances, brominated flame retardants and their metabolites in human breast milk and infant formula. Talanta 2013; 117:318-25. [PMID: 24209347 DOI: 10.1016/j.talanta.2013.08.040] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/22/2013] [Accepted: 08/25/2013] [Indexed: 12/23/2022]
Abstract
In the present study, a novel analytical approach for the simultaneous determination of 18 perfluoroalkyl substances (PFASs) and 11 brominated flame retardants (BFRs) including their hydroxylated metabolites and brominated phenols has been developed and validated for breast milk and infant formula. The sample preparation procedure based on extraction using acetonitrile and subsequent purification by dispersive solid-phase extraction (d-SPE) employing C18 sorbent is rapid, simple and high-throughput. Ultra-high performance liquid chromatography (UHPLC) interfaced with a tandem mass spectrometry (MS/MS) was employed for the identification/quantification of these compounds. The method recoveries of target compounds for both matrices ranged from 80% to 117% with relative standard deviations lower than 28% and quantification limits in the range of 3-200 pg/mL for milk and 5-450 pg/g for infant formula. Within the pilot study, the new method was used for the analysis of PFASs and BFRs in 50 human breast milks and six infant formulas. In the breast milk samples the total contents of PFASs and BFRs were in the range of 38-279 and 45-16,200 pg/mL, respectively. The most abundant PFASs detected in all tested breast milk samples were perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), the latter contaminant was present not only as a linear form but also as a branched isomers. The incidence of BFRs was lower, the only representatives of this group, tetrabromobiphenol A (TBBPA) and α-hexabromocyclododecane (α-HBCD), were detected in less than 30% of breast milk samples. None of the infant formulas contained BFRs, traces of either PFOS, PFOA or PFNA were found in three samples.
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54
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Xu W, Wang X, Cai Z. Analytical chemistry of the persistent organic pollutants identified in the Stockholm Convention: A review. Anal Chim Acta 2013; 790:1-13. [DOI: 10.1016/j.aca.2013.04.026] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 04/08/2013] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
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55
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A rapid method for the determination of perfluoroalkyl substances including structural isomers of perfluorooctane sulfonic acid in human serum using 96-well plates and column-switching ultra-high performance liquid chromatography tandem mass spectrometry. J Chromatogr A 2013; 1305:164-70. [PMID: 23891383 DOI: 10.1016/j.chroma.2013.07.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 01/09/2023]
Abstract
To facilitate high-throughput analysis suitable for large epidemiological studies we developed an automated column-switching ultra-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for determination of perfluorocarboxylic acids (PFCAs; C5, C6, C7, C8, C9, C10, C11, C12, and C13), perfluoroalkyl sulfonic acids (PFSAs; C4, C6, C8, and C10), perfluorooctane sulfonamide (PFOSA), and five groups of structural perfluorooctane sulfonic acid (PFOS) isomers in human serum or plasma. The analytical procedure involves rapid protein precipitation using 96-well plates followed by an automated sample clean-up using an on-line trap column removing many potentially interfering sample components while through the mobile phase gradient the target analytes are eluted onto the analytical column for further separation and subsequent mass detection. The method was linear (R(2)<0.995) at concentrations ranging from 0.01 to 60ngmL(-1) with method detection limits ranging between 0.01 and 0.17ngmL(-1) depending on the analyte. The developed method was precise, with repeatability (n=7) and reproducibility (n=103) coefficients of variation between 2% and 20% for most compounds including PFOS (2% and 8%) and its structural isomers (2-6% and 4-8%). The method was in conformity with a standard reference material. The column-switching HPLC-MS/MS method has been successfully applied for the determination of perfluoroalkyl substances including structural PFOS isomers in human plasma from an epidemiological study.
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56
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Kärrman A, Lindström G. Trends, analytical methods and precision in the determination of perfluoroalkyl acids in human milk. Trends Analyt Chem 2013. [DOI: 10.1016/j.trac.2012.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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57
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Zhang Y, Beesoon S, Zhu L, Martin JW. Isomers of perfluorooctanesulfonate and perfluorooctanoate and total perfluoroalkyl acids in human serum from two cities in North China. ENVIRONMENT INTERNATIONAL 2013; 53:9-17. [PMID: 23314039 DOI: 10.1016/j.envint.2012.12.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 12/12/2012] [Accepted: 12/17/2012] [Indexed: 06/01/2023]
Abstract
The sources and pathways of human exposure to perfluoroalkyl acids (PFAAs) are not well characterized, particularly in China where many perfluorinated substances are now manufactured. Here, isomer-specific PFAA analysis was used for the first time to evaluate exposure sources for Chinese people, by applying the method to 129 serum samples collected in two typical cities (Shijiazhuang and Handan) in North China. Among all samples, total perfluorooctanesulfonate (∑PFOS, mean 33.3 ng/ml) was the predominant PFAA followed by perfluorohexanesulfonate (2.95 ng/ml), total perfluorooctanoate (∑PFOA, 2.38 ng/ml), and perfluorononanoate (0.51 ng/ml). The level of ∑PFOS was higher than in people from North America in recent years. The mean concentrations of ΣPFAAs in the participants living in urban Shijiazhuang (59.0 ng/ml) and urban Handan (35.6 ng/ml) were significantly higher (p<0.001 and p=0.041, respectively) than those living in the rural district of Shijiazhuang (24.3 ng/ml). The young female sub-population had the lowest ΣPFAA concentrations compared with older females and all males. On average, the proportion of linear PFOS (n-PFOS) was only 48.1% of ∑PFOS, which is much lower than what was present in technical PFOS from the major historical manufacturer (ca. 70% linear), and which is also lower than data reported from any other countries. Moreover, the proportion of n-PFOS decreased significantly with increasing ∑PFOS concentration in the serum samples (r=-0.694, p<0.001). Taken together, the data lend weight to previous suggestions that i) high branched PFOS content in serum is a biomarker of exposure to PFOS-precursors, and ii) that people with the highest ∑PFOS concentrations are exposed disproportionately to high concentrations of PFOS-precursors. On average, linear PFOA (n-PFOA) contributed 96.1% of ∑PFOA, significantly higher than in technical PFOA (ca. 75-80% linear), but lower than in Americans, suggesting higher exposure to electrochemically fluorinated PFOA than in other countries, including the United States.
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Affiliation(s)
- Yifeng Zhang
- Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, PR China
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58
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Ma W, Kannan K, Wu Q, Bell EM, Druschel CM, Caggana M, Aldous KM. Analysis of polyfluoroalkyl substances and bisphenol A in dried blood spots by liquid chromatography tandem mass spectrometry. Anal Bioanal Chem 2013; 405:4127-38. [PMID: 23404131 DOI: 10.1007/s00216-013-6787-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 12/20/2012] [Accepted: 01/24/2013] [Indexed: 11/27/2022]
Abstract
Dried blood spots (DBS), collected as part of the newborn screening program (NSP) in the USA, is a valuable resource for studies on environmental chemical exposures and associated health outcomes in newborns. Nevertheless, determination of concentrations of environmental chemicals in DBS requires assays with great sensitivity, as the typical volume of blood available on a DBS with 16-mm diameter disc is approximately 50 μL. In this study, we developed a liquid-liquid extraction and high-performance liquid chromatography/tandem mass spectrometry method for the detection of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), and bisphenol A (BPA) in DBS. The method was validated for accuracy, precision, and sensitivity, by spiking of target chemicals at different levels on Whatman 903 filter cards, which is used in the collection of DBS by the NSP. Contamination arising from collection, storage, and handling of DBS is an important issue to be considered in the analysis of trace levels of environmental chemicals in DBS. For the evaluation of the magnitude of background contamination, field blanks were prepared from unspotted portions of DBS filter cards collected by the NSP. The method was applied for the measurement of PFOS, PFOA, and BPA in 192 DBS specimens provided by NSP of New York State. PFOS and PFOA were detected in 100 % of the specimens analyzed. The concentrations of PFOS and PFOA measured in DBS were similar to those reported earlier in the whole blood samples of newborns. BPA was also found in 86 % of the specimens at concentrations ranging from 0.2 to 36 ng/mL (excluding two outliers). Further studies are needed to evaluate the sources of BPA exposures and health outcomes in newborns.
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Affiliation(s)
- Wanli Ma
- Wadsworth Center, New York State Department of Health, School of Public Health, State University of New York at Albany, Albany, NY 12201-0509, USA
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59
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Benskin JP, Li B, Ikonomou MG, Grace JR, Li LY. Per- and polyfluoroalkyl substances in landfill leachate: patterns, time trends, and sources. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:11532-40. [PMID: 23030600 DOI: 10.1021/es302471n] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Concentrations and isomer profiles for 24 per- and polyfluoroalkyl substances (PFASs) were monitored over 5 months (February-June, 2010) in municipal landfill leachate. These data were used to assess the role of perfluoroalkyl acid (PFAA) precursor degradation on changes in PFAA concentrations over time. The influence of total organic carbon, total suspended solids, pH, electrical conductivity (EC), leachate flow rates, and meteorological data (precipitation, air temperature) on leachate PFAS concentrations was also investigated. Perfluoropentanoate and perfluorohexanoate were typically the dominant PFASs in leachate, except for March-April, when concentrations of perfluorooctane sulfonate, perfluorooctanoate, and numerous PFAA-precursors (i.e., (N-alkyl) perfluorooctane sulfonamides and fluorotelomer carboxylic acids) increased by a factor of 2-10 (~4 μg/L to ~36 μg/L ΣPFASs). During this time, isomer profiles of PFOA became increasingly dominated by the linear isomer, likely from transformation of linear, telomer-manufactured precursors. While ΣPFAA-precursors accounted for up to 71% of ΣPFASs (molar basis) in leachate from this site, leachate from a second landfill displayed only low concentrations of precursors (<1% of ΣPFASs). Overall, degradation of PFAA-precursors and changes in leachate pH, EC, and 24-h precipitation were important factors controlling PFAS occurrence in leachate. Finally, 8.5-25 kg/yr (mean 16 kg/yr) of ΣPFASs was estimated to leave the landfill via leachate for subsequent treatment at a wastewater treatment plant.
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Affiliation(s)
- Jonathan P Benskin
- AXYS Analytical Services Ltd., 2045 Mills Road West, Sidney BC, Canada, V8L 5X2.
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60
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Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food. Anal Bioanal Chem 2012; 404:2193-201. [DOI: 10.1007/s00216-012-6374-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 08/14/2012] [Accepted: 08/17/2012] [Indexed: 01/09/2023]
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61
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Glynn A, Berger U, Bignert A, Ullah S, Aune M, Lignell S, Darnerud PO. Perfluorinated alkyl acids in blood serum from primiparous women in Sweden: serial sampling during pregnancy and nursing, and temporal trends 1996-2010. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:9071-9. [PMID: 22770559 DOI: 10.1021/es301168c] [Citation(s) in RCA: 317] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We investigated temporal trends of blood serum levels of 13 perfluorinated alkyl acids (PFAAs) and perfluorooctane sulfonamide (FOSA) in primiparous women (N = 413) from Uppsala County, Sweden, sampled 3 weeks after delivery 1996-2010. Levels of the short-chain perfluorobutane sulfonate (PFBS) and perfluorohexane sulfonate (PFHxS) increased 11%/y and 8.3%/y, respectively, and levels of the long-chain perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) increased 4.3%/y and 3.8%/y, respectively. Concomitantly, levels of FOSA (22%/y), perfluorooctane sulfonate (PFOS, 8.4%/y), perfluorodecane sulfonate (PFDS, 10%/y), and perfluorooctanoate (PFOA, 3.1%/y) decreased. Thus, one or several sources of exposure to the latter compounds have been reduced or eliminated, whereas exposure to the former compounds has recently increased. We explored if maternal levels of PFOS, PFOA, and PFNA during the early nursing period are representative for the fetal development period, using serial maternal serum samples, including cord blood (N = 19). PFAA levels in maternal serum sampled during pregnancy and the nursing period as well as in cord blood were strongly correlated. Strongest correlations between cord blood levels and maternal levels were observed for maternal serum sampled shortly before or after the delivery (r = 0.70-0.89 for PFOS and PFOA). A similar pattern was observed for PFNA, although the correlations were less strong due to levels close to the method detection limit in cord blood.
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Affiliation(s)
- Anders Glynn
- Department of Research and Development, National Food Agency, P.O. Box 622, SE-751 26 Uppsala, Sweden.
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62
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Asher BJ, Wang Y, De Silva AO, Backus S, Muir DCG, Wong CS, Martin JW. Enantiospecific perfluorooctane sulfonate (PFOS) analysis reveals evidence for the source contribution of PFOS-precursors to the Lake Ontario foodweb. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:7653-60. [PMID: 22676298 DOI: 10.1021/es301160r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Exposure to perfluorooctane sulfonate (PFOS) may arise directly, from emission and exposure to PFOS itself, or indirectly via the environmental release and degradation of PFOS-precursors. Human serum enantiomer fractions (EFs) of 1m-PFOS have been shown to be nonracemic, suggesting that PFOS-precursors are a significant source of PFOS in humans, but little is known about the importance of PFOS-precursors in ecosystems. In the current work, concentrations of PFOS, perfluorooctane sulfonamide (PFOSA), PFOS isomer profiles, and EFs of 1m-PFOS were determined in Lake Ontario water, sediment, fishes and invertebrates. Concentrations of PFOS and PFOSA were highest in slimy sculpin and Diporeia, and concentrations of the two compounds were often correlated. 1m-PFOS was racemic in sediment, water, sculpin and rainbow smelt, but nonracemic in the top predator, lake trout, and all invertebrate species. Furthermore, EFs were correlated with the relative concentrations of PFOS and PFOSA in invertebrates. Overall, these empirical observations with a new analytical tool confirm previous suggestions that PFOS-precursors contribute to PFOS in the food web, likely via sediment. Implications are that future PFOS exposures in this ecosystem will be influenced by an in situ source, and that the apparent environmental behavior of PFOS (e.g., bioaccumulation potential) can be confounded by precursors.
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Affiliation(s)
- Brian J Asher
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada, T6G 2G2
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63
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Rapid characterization of perfluoralkyl carboxylate, sulfonate, and sulfonamide isomers by high-performance liquid chromatography–tandem mass spectrometry. J Chromatogr A 2012; 1247:165-70. [DOI: 10.1016/j.chroma.2012.05.077] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 04/30/2012] [Accepted: 05/23/2012] [Indexed: 11/22/2022]
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64
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Olsen GW, Lange CC, Ellefson ME, Mair DC, Church TR, Goldberg CL, Herron RM, Medhdizadehkashi Z, Nobiletti JB, Rios JA, Reagen WK, Zobel LR. Temporal trends of perfluoroalkyl concentrations in American Red Cross adult blood donors, 2000-2010. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:6330-6338. [PMID: 22554481 DOI: 10.1021/es300604p] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Eleven perfluorinated alkyl acids (PFAAs) were analyzed in plasma from a total of 600 American Red Cross adult blood donors from six locations in 2010. The samples were extracted by protein precipitation and quantified by using liquid chromatography tandem mass spectrometry (HPLC/MS/MS). The anions of the three perfluorosulfonic acids measured were perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS). The anions of the eight perfluorocarboxylic acids were perfluoropentanoate (PFPeA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnA), and perfluorododecanoate (PFDoA). Findings were compared to results from different donor samples analyzed at the same locations collected in 2000-2001 (N = 645 serum samples) and 2006 (N = 600 plasma samples). Most measurements in 2010 were less than the lower limit of quantitation for PFBS, PFPeA, PFHxA, and PFDoA. For the remaining analytes, the geometric mean concentrations (ng/mL) in 2000-2001, 2006, and 2010 were, respectively, PFHxS: (2.25, 1.52, 1.34); PFOS (34.9, 14.5, 8.3); PFHpA (0.13, 0.09, 0.05); PFOA (4.70, 3.44, 2.44); PFNA (0.57, 0.97, 0.83); PFDA (0.16, 0.34, 0.27), and PFUnA (0.10, 0.18, 0.14). The percentage decline (parentheses) in geometric mean concentrations from 2000-2001 to 2010 were PFHxS (40%), PFOS (76%), and PFOA (48%). The decline in PFOS suggested a population halving time of 4.3 years. This estimate is comparable to the geometric mean serum elimination half-life of 4.8 years reported in individuals. This similarity supports the conclusion that the dominant PFOS-related exposures to humans in the United States were greatly mitigated during the phase-out period.
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Affiliation(s)
- Geary W Olsen
- 3M Company, Medical Department, St. Paul, Minnesota, United States.
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65
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Reiner JL, O'Connell SG, Butt CM, Mabury SA, Small JM, De Silva AO, Muir DCG, Delinsky AD, Strynar MJ, Lindstrom AB, Reagen WK, Malinsky M, Schäfer S, Kwadijk CJAF, Schantz MM, Keller JM. Determination of perfluorinated alkyl acid concentrations in biological standard reference materials. Anal Bioanal Chem 2012; 404:2683-92. [PMID: 22476786 DOI: 10.1007/s00216-012-5943-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/05/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022]
Abstract
Standard reference materials (SRMs) are homogeneous, well-characterized materials used to validate measurements and improve the quality of analytical data. The National Institute of Standards and Technology (NIST) has a wide range of SRMs that have mass fraction values assigned for legacy pollutants. These SRMs can also serve as test materials for method development, method validation, and measurement for contaminants of emerging concern. Because inter-laboratory comparison studies have revealed substantial variability of measurements of perfluoroalkyl acids (PFAAs), future analytical measurements will benefit from determination of consensus values for PFAAs in SRMs to provide a means to demonstrate method-specific performance. To that end, NIST, in collaboration with other groups, has been measuring concentrations of PFAAs in a variety of SRMs. Here we report levels of PFAAs and perfluorooctane sulfonamide (PFOSA) determined in four biological SRMs: fish tissue (SRM 1946 Lake Superior Fish Tissue, SRM 1947 Lake Michigan Fish Tissue), bovine liver (SRM 1577c), and mussel tissue (SRM 2974a). We also report concentrations for three in-house quality-control materials: beluga whale liver, pygmy sperm whale liver, and white-sided dolphin liver. Measurements in SRMs show an array of PFAAs, with perfluorooctane sulfonate (PFOS) being the most frequently detected. Reference and information values are reported for PFAAs measured in these biological SRMs.
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Affiliation(s)
- Jessica L Reiner
- Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8392, USA.
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Ross MS, Wong CS, Martin JW. Isomer-specific biotransformation of perfluorooctane sulfonamide in Sprague-Dawley rats. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:3196-3203. [PMID: 22339592 DOI: 10.1021/es204028v] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Great variability exists in perfluorooctane sulfonate (PFOS) isomer patterns in human and wildlife samples, including unexpectedly high percentages (e.g., >40%) of branched isomers in human sera. Previous in vitro tests showed that branched PFOS-precursors were biotransformed faster than the corresponding linear isomer. Thus, high percentages of branched PFOS may be a biomarker of PFOS-precursor exposure in humans. We evaluated this hypothesis by examining the isomer-specific fate of perfluorooctane sulfonamide (PFOSA), a known PFOS-precursor, in male Sprague-Dawley rats exposed to commercial PFOSA via food for 77 days (83.0 ± 20.4 ng kg(-1) day(-1)), followed by 27 days of depuration. Elimination half-lives of the two major branched PFOSA isomers (2.5 ± 1.0 days and 3.7 ± 1.2 days) were quicker than for linear PFOSA (5.9 ± 4.6 days), resulting in a depletion of branched PFOSA isomers in blood and tissues relative to the dose. A corresponding increase in the total branched isomer content of PFOS, the ultimate metabolite, in rat serum was not observed. However, a significant enrichment of 5m-PFOS and a significant depletion of 1m-PFOS were observed, relative to authentic electrochemical PFOS. The data cannot be directly extrapolated to humans, due to known differences in the toxicokinetics of PFOS in rodents and humans. However, the results confirm that in vivo exposure to commercially relevant PFOS-precursors can result in a distinct PFOS isomer profile that may be useful as a biomarker of exposure source.
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Affiliation(s)
- Matthew S Ross
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2 Canada
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67
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Young WM, South P, Begley TH, Diachenko GW, Noonan GO. Determination of perfluorochemicals in cow's milk using liquid chromatography-tandem mass spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:1652-1658. [PMID: 22243628 DOI: 10.1021/jf204565x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This study describes a new method developed for detection of 10 different perfluorochemicals (PFCs) in cow's milk, seven perfluorinated carboxylates and three perfluorinated sulfonate salts. After attempting multiple methods employing both acidic and basic extractions, a basic extraction using 10 mM sodium hydroxide in methanol digestion along with weak anion-exchange solid-phase extraction was employed. Vortex mixing and varying sonication times were compared as part of sample processing. Results show that sonication during sample processing yield decreased recovery of longer chain perfluorinated carboxylates. The final method developed was used to determine the concentration of PFCs in 12 raw and 49 retail milk samples from across the United States. With the exception of a single raw milk sample obtained from a dairy farm that had applied PFC containing biosolids to its fields, there were no milk samples containing PFCs.
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Affiliation(s)
- Wendy M Young
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, Maryland 20740, United States.
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68
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O'Brien JM, Austin AJ, Williams A, Yauk CL, Crump D, Kennedy SW. Technical-grade perfluorooctane sulfonate alters the expression of more transcripts in cultured chicken embryonic hepatocytes than linear perfluorooctane sulfonate. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2011; 30:2846-2859. [PMID: 21994020 DOI: 10.1002/etc.700] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Recently it was discovered that the perfluorooctane sulfonate (PFOS) detected in wildlife, such as fish-eating birds, had a greater proportion of linear PFOS (L-PFOS) than the manufactured technical product (T-PFOS), which contains linear and branched isomers. This suggests toxicological studies based on T-PFOS data may inaccurately assess exposure risk to wildlife. To determine whether PFOS effects were influenced by isomer content, we compared the transcriptional profiles of cultured chicken embryonic hepatocytes (CEH) exposed to either L-PFOS or T-PFOS using Agilent microarrays. At equal concentrations (10 µM), T-PFOS altered the expression of more transcripts (340, >1.5-fold change, p < 0.05) compared with L-PFOS (130 transcripts). Higher concentrations of L-PFOS (40 µM) were also less transcriptionally disruptive (217 transcripts) than T-PFOS at 10 µM. Functional analysis showed that L-PFOS and T-PFOS affected genes involved in lipid metabolism, hepatic system development, and cellular growth and proliferation. Pathway and interactome analysis suggested that genes may be affected through the RXR receptor, oxidative stress response, TP53 signaling, MYC signaling, Wnt/β-catenin signaling, and PPARγ and SREBP receptors. In all functional categories and pathways examined, the response elicited by T-PFOS was greater than that of L-PFOS. These data show that T-PFOS elicits a greater transcriptional response in CEH than L-PFOS alone and demonstrates the importance of considering the isomer-specific toxicological properties of PFOS when assessing exposure risk.
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Affiliation(s)
- Jason M O'Brien
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, Ontario, Canada.
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69
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Wang Y, Beesoon S, Benskin JP, De Silva AO, Genuis SJ, Martin JW. Enantiomer fractions of chiral Perfluorooctanesulfonate (PFOS) in human sera. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:8907-8914. [PMID: 21882865 DOI: 10.1021/es2023434] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is the most prominent perfluoroalkyl contaminant in humans and wildlife, but there is great uncertainty in exposure pathways, particularly with respect to the importance of PFOS-precursors (PreFOS). We explored the hypothesis that nonracemic proportions of chiral PFOS in serum are qualitative and semiquantitative biomarkers of human PreFOS exposure. A new chiral HPLC-MS/MS method was developed for alpha-perfluoromethyl branched PFOS (1m-PFOS, typically 2-3% of total PFOS) and applied to enantiomer fraction (EF) analysis in biological samples. In blood and tissues of rodents exposed subchronically to electrochemical PFOS, 1m-PFOS was racemic (EF = 0.485-0.511) and no evidence for enantioselective excretion was found in this model mammal. 1m-PFOS in serum of pregnant women, from Edmonton, was significantly nonracemic, with a mean EF (±standard deviation) of 0.432 ± 0.009, similar to pooled North American serum. In a highly exposed Edmonton family (mother, father, and 5 children) living in a house where ScotchGard had been applied repeatedly to carpet and upholstery, EFs ranged from 0.35 to 0.43, significantly more nonracemic than in pregnant women. Semiquantitative estimates of % serum 1m-PFOS coming from 1m-PreFOS biotransformation in both subpopulations were in reasonable agreement with model predictions of human exposure to PFOS from PreFOS. The data were overall suggestive that the measured nonracemic EFs were influenced by the relative extent of exposure to PreFOS. The possibility of using 1m-PFOS EFs for assessing the relative contribution of 1m-PreFOS (or PreFOS in general) in biological samples requires further application before being fully validated, but could be a powerful tool for probing general sources of PFOS in environments where the importance of PreFOS is unknown.
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Affiliation(s)
- Yuan Wang
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
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70
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Buck RC, Franklin J, Berger U, Conder JM, Cousins IT, de Voogt P, Jensen AA, Kannan K, Mabury SA, van Leeuwen SPJ. Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2011; 7:513-41. [PMID: 21793199 PMCID: PMC3214619 DOI: 10.1002/ieam.258] [Citation(s) in RCA: 2139] [Impact Index Per Article: 164.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 05/26/2011] [Accepted: 07/05/2011] [Indexed: 05/18/2023]
Abstract
The primary aim of this article is to provide an overview of perfluoroalkyl and polyfluoroalkyl substances (PFASs) detected in the environment, wildlife, and humans, and recommend clear, specific, and descriptive terminology, names, and acronyms for PFASs. The overarching objective is to unify and harmonize communication on PFASs by offering terminology for use by the global scientific, regulatory, and industrial communities. A particular emphasis is placed on long-chain perfluoroalkyl acids, substances related to the long-chain perfluoroalkyl acids, and substances intended as alternatives to the use of the long-chain perfluoroalkyl acids or their precursors. First, we define PFASs, classify them into various families, and recommend a pragmatic set of common names and acronyms for both the families and their individual members. Terminology related to fluorinated polymers is an important aspect of our classification. Second, we provide a brief description of the 2 main production processes, electrochemical fluorination and telomerization, used for introducing perfluoroalkyl moieties into organic compounds, and we specify the types of byproducts (isomers and homologues) likely to arise in these processes. Third, we show how the principal families of PFASs are interrelated as industrial, environmental, or metabolic precursors or transformation products of one another. We pay particular attention to those PFASs that have the potential to be converted, by abiotic or biotic environmental processes or by human metabolism, into long-chain perfluoroalkyl carboxylic or sulfonic acids, which are currently the focus of regulatory action. The Supplemental Data lists 42 families and subfamilies of PFASs and 268 selected individual compounds, providing recommended names and acronyms, and structural formulas, as well as Chemical Abstracts Service registry numbers.
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Affiliation(s)
- Robert C Buck
- E.I. du Pont de Nemours & Co., Inc., DuPont Chemicals and FluoroproductsWilmington, Delaware, USA
| | - James Franklin
- CLF-Chem Consulting3 Clos du Châtaignier, BE-1390 Grez-Doiceau, Belgium
| | - Urs Berger
- Department of Applied Environmental Science (ITM), Stockholm UniversityStockholm, Sweden
| | | | - Ian T Cousins
- Department of Applied Environmental Science (ITM), Stockholm UniversityStockholm, Sweden
| | - Pim de Voogt
- Institute for Biodiversity and Ecosystem Dynamics, University of AmsterdamAmsterdam, The Netherlands
| | - Allan Astrup Jensen
- Nordic Institute for Product Sustainability, Environmental Chemistry and Toxicology (NIPSECT)Frederiksberg, Denmark
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at AlbanyAlbany, New York, USA
| | - Scott A Mabury
- Department of Chemistry, University of TorontoToronto, Ontario, Canada
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71
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Simultaneous determination of perfluoroalkyl phosphonates, carboxylates, and sulfonates in drinking water. J Chromatogr A 2011; 1218:6388-95. [DOI: 10.1016/j.chroma.2011.07.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/21/2011] [Accepted: 07/01/2011] [Indexed: 11/23/2022]
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72
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Berger U, Kaiser MA, Kärrman A, Barber JL, van Leeuwen SPJ. Recent developments in trace analysis of poly- and perfluoroalkyl substances. Anal Bioanal Chem 2011; 400:1625-35. [DOI: 10.1007/s00216-011-4823-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 02/16/2011] [Accepted: 02/19/2011] [Indexed: 10/18/2022]
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Gannon SA, Johnson T, Nabb DL, Serex TL, Buck RC, Loveless SE. Absorption, distribution, metabolism, and excretion of [1-¹⁴C]-perfluorohexanoate ([¹⁴C]-PFHx) in rats and mice. Toxicology 2011; 283:55-62. [PMID: 21349313 DOI: 10.1016/j.tox.2011.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/09/2011] [Accepted: 02/15/2011] [Indexed: 01/09/2023]
Abstract
The absorption, tissue distribution, elimination, and metabolism of [1-¹⁴C]-PFHx in rats and mice dosed orally at 2 or 100 mg/kg was evaluated following a single dose or after 14 consecutive doses. Absorption was rapid in rats as evidenced by a short time to maximum concentration (C(max)) of 30 min in male rats and 15 min in female rats at both the 2 and 100mg/kg dose level. The plasma elimination half-life was somewhat longer in males (1.5-1.7 h) than in females (0.5-0.7 h). Absorption in the mouse was also rapid with the maximum plasma concentration occurring between 15 and 30 min after dosing. The maximum concentration was not appreciably different between male and female mice (8 μg equiv./g at 2 mg/kg; ~350 μg equiv./g at 100 mg/kg). The primary route of elimination was via the urine. PFHx was not metabolized in rat or mouse hepatocytes, nor were any metabolites observed after oral dosing in either rodent species. Essentially 100% of the dose was eliminated in urine within 24 h demonstrating that PFHx is readily absorbed and bioavailability approaches 100%, even at a dose as high as 100 mg/kg. The route and extent of elimination was unchanged after 14 days of daily dosing. Tissues were collected at three time points (rat: 0.5, 2, and 24 h; mice: 0.25, 1, and 24 h) after dosing to investigate the tissue clearance kinetics of PFHx following a single dose at 2 or 100 mg/kg. In all tissues except skin, PFHx was not quantifiable 24 h after dosing in both sexes of the two species.
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Affiliation(s)
- Shawn A Gannon
- DuPont Haskell Global Centers for Health and Environmental Sciences, Elkton Rd, Newark, DE 19714-0050, USA.
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74
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Malinsky MD, Jacoby CB, Reagen WK. Determination of perfluorinated compounds in fish fillet homogenates: Method validation and application to fillet homogenates from the Mississippi River. Anal Chim Acta 2011; 683:248-57. [DOI: 10.1016/j.aca.2010.10.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 10/19/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
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75
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Sharpe RL, Benskin JP, Laarman AH, Macleod SL, Martin JW, Wong CS, Goss GG. Perfluorooctane sulfonate toxicity, isomer-specific accumulation, and maternal transfer in zebrafish (Danio rerio) and rainbow trout (Oncorhynchus mykiss). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:1957-66. [PMID: 20821653 DOI: 10.1002/etc.257] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Perfluorooctane sulfonate (PFOS; C(8)F(17)SO(3) (-)) bioaccumulation and toxicity have been demonstrated in both aquatic and terrestrial organisms. The majority of investigations have examined total PFOS concentrations in wildlife and in toxicity testing, but isomer-specific monitoring studies are less common, and no laboratory-based study of PFOS isomer accumulation in fish has been reported. The present study examined accumulation and maternal transfer of PFOS isomers in zebrafish and tissue-specific accumulation of PFOS isomers in trout parr. A median lethal dose (LC50) of 22.2 and 2.5 mg/L was calculated for adult zebrafish and trout parr, respectively. A two-week PFOS exposure resulted in tissue-specific PFOS accumulation in trout, with maximum concentrations identified in the liver tissue (>50 microg/g). Prior exposure to PFOS as alevin did not affect the accumulation of PFOS in tissues later in life. In both species, accumulation of branched PFOS isomers generally occurred to a lesser extent than linear PFOS, which may explain the relative deficiency of branched PFOS isomers in some aquatic species in the field. Analysis of exposed trout tissues indicated that isomer discrimination may occur at the level of elimination or uptake and elimination processes in the kidney or gill, respectively. When zebrafish underwent a reproductive cycle in the presence of PFOS, approximately 10% (wt) of the adult PFOS body burden was transferred to the developing embryos, resulting in a higher total PFOS concentration in eggs (116 +/- 13.3 microg/g) than in the parent fish (72.1 +/- 7.6 microg/g). The isomer profile in eggs was not significantly different from that of adults, suggesting that the maternal transfer of branched and linear PFOS isomers in fish is largely nonisomer specific.
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Affiliation(s)
- Rainie L Sharpe
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T5G 2E9, Canada
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76
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Lee WW, Chang WH, Pyo HS, Kang TS, Hong JK. Analytical trend of perfluorinated compounds in environmental and biota samples. ANALYTICAL SCIENCE AND TECHNOLOGY 2010. [DOI: 10.5806/ast.2010.23.4.331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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77
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Richardson SD. Environmental Mass Spectrometry: Emerging Contaminants and Current Issues. Anal Chem 2010; 82:4742-74. [DOI: 10.1021/ac101102d] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Susan D. Richardson
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Athens, Georgia 30605
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Benskin JP, De Silva AO, Martin JW. Isomer profiling of perfluorinated substances as a tool for source tracking: a review of early findings and future applications. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 208:111-60. [PMID: 20811863 DOI: 10.1007/978-1-4419-6880-7_2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The two major manufacturing techniques for perfluorochemicals can be distinguished based on the isomeric profile of their products. ECF (major use from 1950s to 2002) results in a product containing both linear and branched isomers, while telomerization (major use from 2002 to present) typically yields an isomerically pure, linear product. Among the most important question today, which has implication for future regulation of these chemicals, is to what extent human and environmental exposure is from historical products (i.e., ECF) versus currently manufactured fluorochemicals (i.e., telomer). Perfluoroalkyl-chain branching can also affect the physical and chemical properties of these chemicals, which may influence their environmental transport and degradation, partitioning, bioaccumulation, pharmacokinetics, and toxicity. Unless perfluorinated substances are considered as individual isomers, much of this information will be overlooked or missed altogether, which could potentially lead to inaccuracies in human and environmental risk assessments. In this review, we have highlighted novel findings, current knowledge gaps, and areas for improvement based on early experiments on the disposition of PFA and PFA-precursor isomers in the environment. We have also emphasized the wealth of information that can potentially be gleaned from future work in this area, which renders routine adoption of isomer-specific methodologies an attractive and logical next step in the progression of fluorochemicals analysis. However, despite vast improvements in recent years, a fast and comprehensive method capable of separating all major PFA and PFA-precursor isomers, while removing interferences is still required before these methods becomes routine in most labs. Purified and characterized standards of PFOA and PFOS that have isomer profiles consistent with those of historically produced (i.e., 3M) PFOS and PFOA are also required. The limited data available on PFA isomer profiles that exist in the environment and the biological properties of each isomer suggest that examination of isomer profiles may yield clues on the source of PFA contamination to human and the environment. For example, contributions from historical versus current PFOA emissions can be quantified by examining the isomer profile in abiotic samples . Similarly, residual PFOS/PFOA in pre-2002 consumer products may be distinguished from directly emitted PFOS/PFOA by the existence of slight difference in isomer profile. PFOS signatures may also have the potential to distinguish between indirect exposure (via precursors) versus direct exposure (via the sulfonate), based on findings of isomer-specific and/or enantiospecific biotransformation in vitro. Isomer-specific monitoring extended to longer-chain PFAs may also be informative in determining current and historical exposure sources. Finally, given the recent increase of production of PFOSF-based chemicals, following their 2002 phase out, the ability of using isomer profiles to distinguish between historical and currently produced PFOS may also be possible.
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Affiliation(s)
- Jonathan P Benskin
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, T6G 2G3, Canada.
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79
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Hanssen L, Röllin H, Odland JØ, Moe MK, Sandanger TM. Perfluorinated compounds in maternal serum and cord blood from selected areas of South Africa: results of a pilot study. ACTA ACUST UNITED AC 2010; 12:1355-61. [DOI: 10.1039/b924420d] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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80
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Benskin JP, Holt A, Martin JW. Isomer-specific biotransformation rates of a perfluorooctane sulfonate (PFOS)-precursor by cytochrome P450 isozymes and human liver microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:8566-72. [PMID: 20028053 DOI: 10.1021/es901915f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The exposure sources of perfluorooctane sulfonate (PFOS) in humans and wildlife are not well characterized. Human biomonitoring data show that PFOS profiles may consist of up to approximately 50% branched isomers, despite the fact that historical direct manufacturing of PFOS generally resulted in products containing no more than approximately 30% branched isomers. These observations cannot be explained based on what is known about the pharmacokinetics of branched PFOS isomers; thus, here we examined the relative isomer-specific biotransformation rates of a model PFOS-precursor (N-ethylperfluorooctane sulfonamide, NEtFOSA) with human microsomes and recombinant human cytochrome P450s (CYPs) 2C9 and 2C19. Using solid phase microextraction-gas chromatography-electron capture detection to monitor NEtFOSA disappearance, and liquid chromatography-tandem mass spectrometry to monitor product formation, we showed that, in general, human microsomes and CYP isozymes transformed the branched isomers more rapidly than linear NEtFOSA. Among branched isomers, perfluoroalkyl branching geometry significantly influenced the rate of biotransformation. As a result, PFOS isomer patterns in biota exposed predominantly to precursors could be much different than expected from the isomer pattern of the precursor. While these data are suggestive that the relatively high abundance of branched PFOS isomers present in some humans, or wildlife, may be explained by substantial exposure to PFOS-precursors, in vivo studies with other relevant PFOS-precursors are warranted to validate this as a biomarker of exposure source.
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Affiliation(s)
- Jonathan P Benskin
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine, University of Alberta, Canada
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