| 1. |
- Weiner, Barbara, et al.
(författare)
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Organic fluorine content in aqueous film forming foams (AFFFs) and biodegradation of the foam component 6 : 2 fluorotelomermercaptoalkylamido sulfonate (6: 2 FTSAS)
- 2013
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Ingår i: Environmental Chemistry. - : CSIRO Publishing. - 1448-2517 .- 1449-8979. ; 10:6, s. 486-493
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Tidskriftsartikel (refereegranskat)abstract
- Environmental context Total organofluorine and known fluorosurfactants were quantified in 11 aqueous film forming foams (AFFFs) used to extinguish fires in Ontario, Canada, and one commercial AFFF product. By comparing the concentrations of known fluorosurfactants with the total organofluorine, less than 10% of the fluorosurfactants were identified in half of the samples. Our biodegradation experiment with one of the fluorosurfactants using waste-water treatment plant sludge showed that it was a potential source of perfluoroalkyl carboxylates, which are persistent in the environment. Abstract Eleven aqueous film forming foam (AFFF) samples that were used to extinguish fires in Ontario, Canada, and one commercial product, were analysed using a variety of analytical techniques to obtain structural information and quantities of organofluorine and known perfluoroalkyl and polyfluoroalkyl substances (PFASs). The NMR spectra of the foams distinguished the fluorosurfactants that were synthesised by either electrochemical fluorination or telomerisation. Total organofluorine content was quantified using total organofluorine-combustion ion chromatography (TOF-CIC), which revealed that the samples contained from 475 to 18000gFmL-1. The common AFFF component 6:2 fluorotelomermercaptoalkylamido sulfonate (FTSAS) was quantified by liquid chromatography tandem mass spectrometry (LC-MS/MS) together with perfluoroalkane sulfonates (PFSAs), perfluoroalkyl carboxylates (PFCAs) and fluorotelomer sulfonates (FTSAs); in five samples, 6:2 FTSAS was present in concentrations greater than 1000gmL-1. By comparing the concentrations of these quantifiable fluorochemicals with the total organofluorine content, it was evident that in half of the AFFF samples, less than 10% of the fluorochemicals were identified; in two of the samples, perfluorooctane sulfonate (PFOS) accounted for ∼50% of the total organofluorine content. Our degradation experiment with 6:2 FTSAS using waste-water treatment plant sludge showed that 6:2 FTSAS was a potential source of FTSAs, fluorotelomer alcohols and PFCAs in the environment.
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| 2. |
- Joudan, Shira, et al.
(författare)
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Biological cleavage of the C-P bond in perfluoroalkyl phosphinic acids in male Sprague-Dawley rats and the formation of persistent and reactive metabolites
- 2017
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Ingår i: Journal of Environmental Health Perspectives. - : National Institute of Environmental Health Sciences (NIEHS). - 0091-6765 .- 1552-9924. ; 125:11
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
- Loi, Eva I. H., et al.
(författare)
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Detections of Commercial Fluorosurfactants in Hong Kong Marine Environment and Human Blood : A Pilot Study
- 2013
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:9, s. 4677-4685
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Tidskriftsartikel (refereegranskat)abstract
- Previously, much of the perfluoroalkyl and polyfluoroalkyl substance (PFAS) research has focused on perfluoroalkyl carboxylates (PFCAs) or perfluoroalkane sulfonates (PFSAs). Recent studies indicate that known PFCAs and PFSAs accounted for 5-95% of the organofluorine (OF) in human and wild rat blood samples suggesting that a relatively large proportion of OF remained unknown. Until recently, some studies reported commercially available compounds such as polyfluoroalkyl phosphate diesters (diPAPs) and fluorotelomer sulfonates (FTSAs) in human blood and sludge samples. The present investigation is a pilot study aiming at surveying some newly identified PFASs such as diPAPs, FTSAs, and perfluorinated phosphinates (PFPiAs) in different environmental samples including surface water, sediment, sewage treatment plant influent and effluent, sludge, benthic worm, and human blood from Hong Kong. DiPAPs (6:2, 6:2/8:2, and 8:2) were detected in some of the samples at part-per-billion (ppb) levels in sludge, sub ppb levels in influent and effluent, sediment, worm, and human blood samples, and sub part-per-trillion (ppt) levels in surface waters. Sub ppt to ppb levels of 6:2 and 8:2 FTSAs were observed in worm, surface water, and human blood samples. PFPiAs were only observed in worm samples. The detected "new PFASs" accounted for a minor proportion (less than 5%) of the total PFASs in benthic worm and human blood, but up to 95% in sewage sludge samples from Hong Kong. This is the first report of commercial fluorosurfactants (PFPiAs, diPAPs, and FTSAs) in the samples from the environment and human blood in Hong Kong; further information on the distribution, fate, and transport of "new PFASs" in other Asian cities, as well as toxicity, is needed for further assessing the human exposure and risk.
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| 4. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Are humans exposed to increasing amounts of unidentified organofluorine?
- 2016
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Ingår i: Environmental Chemistry. - : CSIRO Publishing. - 1448-2517 .- 1449-8979. ; 13:1, s. 102-110
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Tidskriftsartikel (refereegranskat)abstract
- Samples of human plasma (n=122) from two German cities (collected in 1982-2009, excluding 1994) and whole blood (n=47) from seven Chinese cities (collected in 2004) were analysed for 52 polyfluoroalkyl/perfluoroalkyl substances (PFASs) using LC-MS/MS. Quantifiable PFASs included some newly identified and commercially available chemicals PFPAs, PFPiAs, FTSAs, PAPs and di-SAmPAP, metabolites of fluorotelomer-based products (FTCAs/FTUCAs), PFCAs, PFSAs, FASAs and FOSAAs. The blood samples were also analysed for extractable organofluorine (EOF) using total organofluorine combustion ion chromatography (TOF-CIC). Seven more PFASs (C7 and C10 PFSAs, FOSAA, MeFOSAA, EtFOSAA, C13 PFCA and 8 : 2 FTSA) were detected in the Chinese samples than had been previously reported. For the German samples, PFHpS, FOSA, MeFOSA, EtFOSA, FTSAs (6 : 2, 8 : 2), PFPAs (C6, C8) and PFPiAs (C6/C6, C6/C8, C8/C8) were additional chemicals identified that were not measured in the earlier studies. Those newly identified and commercially available PFASs were either at trace levels (pg mL-1) or not detected. A mass balance of fluorine between quantifiable PFAS and EOF in the Chinese samples indicated quantifiable PFASs accounted for 31-86% of EOF. For the German samples, the quantifiable PFAS accounted for 52-100% and 57-100% of EOF in Münster and Halle samples respectively. After the year 2000, an increasing amount and proportion of unidentified organofluorine were observed in Munster samples. The increasing trend of unidentified organofluorine in plasma samples suggested humans are being exposed to new and unidentified fluorinated products.
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| 5. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Bioconcentration of Aqueous Film-Forming Foam (AFFF) in Juvenile Rainbow Trout (Oncorhyncus mykiss)
- 2013
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:21, s. 12505-12513
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Tidskriftsartikel (refereegranskat)abstract
- This work investigated the bioconcentration of PFASs in juvenile rainbow trout by exposing the fish in separate tanks under flow-through conditions to water continuously spiked with either of the AFFFs FC-203CF light water AFFF 3% (3M) or Niagara 1-3 (Angus Fire); a nonspiked tank served as the control. Three fish in each tank were collected after 1, 3, 6, and 11 days of exposure, and 3, 7, 14, and 25 days of depuration. Liver and carcass homogenate samples were analyzed for 20 PFASs using LC-MS/MS. PFDS, PFOS, PFHxS, and EtFOSAA were detected in fish exposed to the 3M foam, while 6:2 and 8:2 FTSASs, 6:2 and 8:2 FTSAs, 5:3 and 7:3 FTCAs were measured in fish exposed to Angus Fire foam. Bioconcentration factors and rate constants for uptake and depuration were calculated. Total and extractable organofluorine were measured in the fish samples. After fish were exposed to AFFFs, not only known PFASs but also other unknown organofluorines were bioconcentrated. Compared to the control group, significantly greater amounts (at least 10-fold) and proportion of unidentified PFASs were found in both liver and carcass homogenate ranging from ∼50% in 3M foam up to 95% in the Angus Fire foam at the end of exposure.
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| 6. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Part I. A Temporal Study of PFCAs and Their Precursors in Human Plasma from Two German Cities 1982-2009
- 2013
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Ingår i: Environmental Science and Technology. - Washington, USA : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:8, s. 3865-3874
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Tidskriftsartikel (refereegranskat)abstract
- A total of 420 human plasma samples from two cities (Halle and Münster, Germany), collected between 1982 and 2009, were analyzed for a suite of PFCAs (C6−C12) and selected PFCA precursors (4:2-, 4:2/6:2-, 6:2-, 6:2/8:2-, 8:2-, 8:2/10:2-, and 10:2-diPAPs). PFCAs (C7−C11 and C13) were detected in over 80% of the samples (<0.005−39.4 ng/mL), while C12 PFCA was detected in fewer than 10% of the samples. In a range of 10−46% of the samples, 4:2-, 4:2/6:2-, 6:2, and 8:2-diPAPs were identified at concentrations of <0.0002−0.687 ng/mL; fewer than 10% of the samples had detectable 10:2-diPAP. Temporal trends (2000−2009) showed increasing concentrations of PFNA, PFDA, and PFUnDA, whereas PFOA concentrations were decreasing. Calculated population halving time for PFOA varied between 8.2−14.5 years, which contrasts to the generally accepted value of 3.8 years. This suggests an ongoing or additional exposure to PFOA or one of its precursor compounds. DiPAPs, known to metabolize rapidly to PFCAs, were detected in a significant number of samples and at concentrations that have not declined significantly over the past half-decade. The evidence suggests they have contributed to the continued presence of the longer chain PFCAs and perhaps contribute to the slow decline of PFOA.
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| 7. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Part II. A Temporal Study of PFOS and Its Precursors in Human Plasma from Two German Cities in 1982-2009
- 2013
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Ingår i: Environmental Science and Technology. - Washington, USA : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 47:8, s. 3875-3882
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Tidskriftsartikel (refereegranskat)abstract
- A total of 420 human plasma from two cities (Halle and Münster, Germany) collected between 1982 and 2009, were analyzed for a suite of PFSAs (C4, C6, C8, C10) and selected PFOS precursors (MeFOSAA, EtFOSAA, FOSAA, di-SAmPAP). Among these target analytes, only di- SAmPAP was used in consumer products. PFSAs (C6 and C8), MeFOSAA, EtFOSAA, and FOSAA were detected in over 95% of the samples (<0.0011−116.0 ng/mL), PFDS was detected in approximately 40% of the samples (<0.005−0.0998 ng/mL), and di-SAmPAP was detected in 17% of the samples (<0.005−0.0137 ng/mL). Significant positive correlations were found between PFOS and PFHxS, MeFOSAA, EtFOSAA, and FOSAA. Temporal trends of decreasing concentration were identified for PFOS, MeFOSAA, EtFOSAA, and FOSAA, but not for PFHxS. Di-SAmPAP, a common food-contact paper surfactant and expected PFOS precursor, was detected infrequently (25% in samples prior to 2000) in samples before 2006. Population halving times of PFOS, MeFOSAA, EtFOSAA, and FOSAA were estimated. The observed reduction of these chemicals over time in human plasma is presumably related to the phase-out of POSF-based products beginning in 2000. The detection of di-SAmPAP in human sera is significant because this chemical is expected to be metabolized or degraded to PFOS in humans and the environment. Our detection of di-SAmPAP is the first confirmation of human exposure to this commercially available product which is a plausible source of PFOS in humans.
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| 8. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Perfluoroalkyl substances and extractable organic fluorine in surface sediments and cores from Lake Ontario
- 2013
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 59, s. 389-397
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Tidskriftsartikel (refereegranskat)abstract
- Fourteen perfluoroalkyl substances (PFASs) including short-chain perfluorocarboxylates (PFCAs, C4-C6) and perfluoroalkane sulfonates (PFSAs, C4 and C6) were measured in surface sediment samples from 26 stations collected in 2008 and sediment core samples from three stations (Niagara, Mississauga, and Rochester basins) collected in 2006 in Lake Ontario. Perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), and perfluoroundecanoate (PFUnDA) were detected in all 26 surface sediment samples, whereas perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonamide (FOSA), perfluorododecanoate (PFDoDA) and perfluorobutanoate (PFBA) were detected in over 70% of the surface sediment samples. PFOS was detected in all of the sediment core samples (range: 0.492-30.1ngg-1 d.w.) over the period 1952-2005. The C8 to C11 PFCAs, FOSA, and PFBA increased in early 1970s. An overall increasing trend in sediment PFAS concentrations/fluxes from older to more recently deposited sediments was evident in the three sediment cores. The known PFCAs and PFSAs accounted for 2-44% of the anionic fraction of the extractable organic fluorine in surface sediment, suggesting that a large proportion of fluorine in this fraction remained unknown. Sediment core samples collected from Niagara basin showed an increase in unidentified organic fluorine in recent years (1995-2006). These results suggest that the use and manufacture of fluorinated organic compounds other than known PFCAs and PFSAs has diversified and increased.
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| 9. |
- Yeung, Leo W. Y., 1981-, et al.
(författare)
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Simultaneous analysis of perfluoroalkyl and polyfluoroalkyl substances including ultrashort-chain C2 and C3 compounds in rain and river water samples by ultra performance convergence chromatography
- 2017
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Ingår i: Journal of Chromatography A. - : Elsevier. - 0021-9673 .- 1873-3778. ; 1522, s. 78-85
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Tidskriftsartikel (refereegranskat)abstract
- An analytical method using ultra performance convergence chromatography (UPC(2)) coupled to a tandem mass spectrometer operated in negative electrospray mode was developed to measure perfluoroalkyl and polyfluoroalkyl substances (PFASs) including the ultrashort-chain PFASs (C2-C3). Compared to the existing liquid chromatography tandem mass spectrometry method using an ion exchange column, the new method has a lower detection limit (0.4pg trifluoroacetate (TFA) on-column), narrower peak width (3-6s), and a shorter run time (8min). Using the same method, different classes of PFASs (e.g., perfluoroalkyl sulfonates (PFSAs) and perfluorinated carboxylates (PFCAs), perfluorinated phosphonates (PFPAs) and phosphinates (PFPiAs), polyfluoroalkyl phosphate diesters (diPAPs)) can be measured in a single analysis. Rain (n=2) and river water (n=2) samples collected in Toronto, ON, were used for method validation and application. Results showed that short-chain PFAS (C2-C7 PFCAs and C4 PFSA) contributed to over 80% of the detectable PFASs in rain samples and the C2-C3 PFASs alone accounted for over 40% of the total. Reports on environmental levels of these ultrashort-chain PFASs are relatively scarce. Relatively large contribution of these ultrashort-chain PFASs to the total PFASs indicate the need to include the measurement of short-chain PFASs, especially C2 and C3 PFASs, in environmental monitoring. The sources of TFA and other short-chain PFASs in the environment are not entirely clear. The newly developed analytical method may help further investigation on the sources and the environmental levels of these ultrashort-chain PFASs.
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