Health & Environmental Research Online (HERO)


Per- and Polyfluoroalkyl Substances (PFAS)


86 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Synthesis of fluorinated polycarbonate-based polyurethane acrylate for UV-curable coatings

Authors: Liu, J; Wang, B; Yuan, Yan; Liu, Ren; Li, Z; Liu, X (2017) HERO ID: 3859231

[Less] Fluorinated polycarbonate-based UV-curable polyurethane acrylate (F-PCUA) was synthesized by incorporating . . . [More] Fluorinated polycarbonate-based UV-curable polyurethane acrylate (F-PCUA) was synthesized by incorporating 1H, 1H, 2H, 2H-Perfluoro-1-octanol to the end of polycarbonate-based PUA chains. The structure of F-PCUA was determined by H-1-NMR, F-19-NMR, and FTIR analyses. The physical, surface, and thermal properties of F-PCUA were also examined. The F-PCUA was used as a hydrophobic additive in PUA coatings, and the water and oil wettability of the UV-cured film was investigated by contact angle measurements. The results showed that the coating system had great hydrophobicity. Furthermore, X-ray photoelectron spectroscopy research confirmed that a hydrophobic fluorine-enriched surface was obtained in the coating system. Moreover, the mechanical and chemical properties of the hydrophobic coatings did not show deterioration with the introduction of elemental F.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Fluorinated Candle Soot as the Lubricant Additive of Perfluoropolyether

Authors: Huang, G; Yu, Q; Ma, Z; Cai, M; Zhou, F; Liu, W (2017) Tribology Letters 65. HERO ID: 3857371

[Less] In order to improve the tribological properties of perfluoropolyethers (PFPE), fluorinated candle soot . . . [More] In order to improve the tribological properties of perfluoropolyethers (PFPE), fluorinated candle soot is adopted as the lubricant additive because of their special onion-like structure. The candle soot particles (CSP) are modified by 1H, 1H, 2H, 2H-perfluorooctanol (CSP-PFHE nanoparticles), and after the fluorination, they exhibit good dispersivity in PFPE. The mixtures composed of CSP-PFHE nanoparticles and PFPE possess better tribological performance than neat PFPE under different test conditions including variable temperature, the irradiation of atomic oxygen and extreme pressure. The reason can be attributed to that the graphene layers are exfoliated from the surfaces of nanoparticles and adhere onto the steel surfaces to form the tribofilm, which can protect the sliding pairs surfaces from friction and severe wear. Meanwhile, the redundant nanoparticles act as the rolling bearing between the sliding surfaces to decrease the wear and some are packed into the corrosion pits generated by PFPE to prevent further erosion in the process of friction. At the end, the lubricating mechanism of CSP-PFHE nanoparticles as additives of PFPE is proposed based on the test results of scanning electron microscope, contact electrical resistance and X-ray photoelectron spectroscopy.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Fluorophilicity and lipophilicity of fluorinated rhodamines determined by their partition coefficients in biphasic solvent systems

Authors: Jbeily, M; Kressler, J (2017) HERO ID: 3859230

[Less] The 1-octanol/water (In P-o/w) and perfluoro(methylcyclohexane)/toluene (In P-PFMC/Tol) partition coefficients . . . [More] The 1-octanol/water (In P-o/w) and perfluoro(methylcyclohexane)/toluene (In P-PFMC/Tol) partition coefficients were measured for four fluorinated rhodamine-based fluorescence dyes (F-rhodamines) functionalized with F-ponytails of various lengths CnH2n-CmF2m+1 (n = 1,2 and m = 3,7,8,10) at both amine groups. Here, the In P-o/w accounts usually for the lipophilic-hydrophilic ratio in ageous (biological) media whereas the In P-PFMC/Tol is a standard value for the description of the fluorophilic-lipophilic ratio. Both partition coefficients correlated with the CmF2m+1/CnH2n ratio, but not directly with the length of the F-ponytails. The ability of the F-rhodamines to incorporate into the hydrophobic part of the bilayer of giant unilamellar vesicles (GUVs) of 1,2-dioleoyl-sn-glycero-3-phosphbcholine (DOPC) mixed with 1H,1H,2H,2H-perfluoro-1-octanol (F6H2OH) using confocal laser scanning microscopy was tested and the partitioning of the F-rhodamines into the mixed GUVs could not be explained exclusively using the two In P values mentioned above. Two other partition coefficients between F6H2OH/W (In P-F6H2OH/W) and perfluoro-n-octane/n-octane (In PF-oct/oct) were measured. The In PF-oct/oct correlated in a comparable way with the In P-PFMC/Tol, whereas In P-F6H2OH/W accounting for the fluorophilic-hydrophilic ratio correlated with the length of the F-ponytails and additionally clarified the different staining abilities of the synthesized F-rhodamines in the mixed GUVs. (C) 2016 Elsevier B.V. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Impact of 6:2 fluorotelomer alcohol aerobic biotransformation on a sediment microbial community

Authors: Zhang, S; Merino, N; Wang, N; Ruan, T; Lu, X (2017) Science of the Total Environment 575:1361-1368. HERO ID: 3857384

[Less] Sediment microbial communities are responsible for many chemical biotransformation processes in the . . . [More] Sediment microbial communities are responsible for many chemical biotransformation processes in the aquatic environment and play a critical role in various ecosystems and biogeochemical cycling. However, the impact of polyfluoroalkyl substances on sediment microbial communities remains unclear. These substances are increasingly being used in consumer and industrial products to replace environmentally persistent perfluoroalkyl substances. In this study, we investigated the effects of low (5mg/L) and high (15mg/L) doses of 6:2 fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] on the structure of a sediment microbial community. 6:2 FTOH biotransformation was rapid in the sediment mixture with a half-life <3days, regardless of the initial doses. After 28days, major products produced in the high dose condition included 28mol% 5:2 sFTOH [F(CF2)5CH(OH)CH3], 9.6mol% 5:3 Acid [F(CF2)5CH2CH2COOH] and 11mol% PFHxA [F(CF2)5COOH], while 73mol% 5:2 sFTOH, 23mol% 5:3 Acid and 26mol% PFHxA were observed in the low dose condition. In the original (control) sediment without 6:2 FTOH dosing, Proteobacteria was the predominant microorganism (18%), followed by Chloroflexi (14%), Verrucomicrobia (13%), Firmicutes (3.4%), Bacterioidetes (2.4%), Actinobacteria (1.7%) and Planctomycetes (1.3%). The presence of 6:2 FTOH and the accumulation of transient transformation products in the sediment exerted selection pressure on the microbial taxonomic distribution and diversity. Our observations indicate that potential 6:2 FTOH degraders and tolerant strains, such as Dokdonella spp., Thauera spp., Albidovulum spp. and Caldanaerovirga spp., existed in the sediment mixture and began to dominate over time. This suggests that these genera might have higher tolerance towards elevated 6:2 FTOH and its transformation products. These findings on the characterization of sediment microbial community stability and dynamics will help predict changes in response to perfluoroalkyl and polyfluoroalkyl substances and also help identify robust microbial strains to degrade polyfluoroalkyl substances in the environment.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Is there a human health risk associated with indirect exposure to perfluoroalkyl carboxylates (PFCAs)?

Authors: Rand, AA; Mabury, SA (2017) Toxicology 375:28-36. [Review] HERO ID: 3455968

[Less] The production and widespread use of poly- and perfluoroalkyl substances (PFAS) has led to their presence . . . [More] The production and widespread use of poly- and perfluoroalkyl substances (PFAS) has led to their presence in the environment, wildlife, and humans. Particularly, the perfluoroalkyl carboxylates (PFCAs) are pervasive throughout the world and have been found at ng/mL concentrations in human blood. PFCAs, especially those having longer carbon chain lengths (≥C6), are associated with developmental and hormonal effects, immunotoxicity, and promote tumor growth in rodents through their role as PPARα agonists. Humans are directly exposed to PFCAs primarily through contaminated food, drinking water, and house dust. However, indirect exposure to PFCAs through the biotransformation of fluorotelomer-based substances may also be a significant, yet relatively underappreciated pathway. We are exposed to fluorotelomer-based substances through use of consumer products, ingestion of food, or from inhalation of dust particles, but the risk of this exposure has been largely uncharacterized. Here, we summarize the work that has been done to characterize toxicity of the classes of fluorotelomer-based substances shown to biotransform to PFCAs: the polyfluoroalkyl phosphate esters (PAPs), fluorotelomer alcohols (FTOHs), fluorotelomer iodides (FTIs), and fluorotelomer acrylate monomers (FTAcs). These fluorotelomer-based substances biotranform to yield PFCAs, yet also form bioactive intermediate metabolites, which have been observed to be more toxic than their corresponding PFCAs. We address what is known regarding the toxicity of the fluorotelomer-based substances and their metabolites, with focus on covalent binding to biological nucleophiles, such as glutathione, proteins, and DNA, as a possible mechanism of toxicity that may influence the risk of indirect exposure to PFCAs.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Perfluoroalkyl acids and their precursors in indoor air sampled in children's bedrooms

Authors: Winkens, K; Koponen, J; Schuster, J; Shoeib, M; Vestergren, R; Berger, U; Karvonen, AM; Pekkanen, J; Kiviranta, H; Cousins, IT (2017) Environmental Pollution 222:423-432. HERO ID: 3857420

[Less] The contamination levels and patterns of perfluoroalkyl acids (PFAAs) and their precursors in indoor . . . [More] The contamination levels and patterns of perfluoroalkyl acids (PFAAs) and their precursors in indoor air of children's bedrooms in Finland, Northern Europe, were investigated. Our study is among the most comprehensive indoor air monitoring studies (n = 57) and to our knowledge the first one to analyse air in children's bedrooms for PFASs (17 PFAAs and 9 precursors, including two acrylates, 6:2 FTAC and 6:2 FTMAC). The most frequently detected compound was 8:2 fluorotelomer alcohol (8:2 FTOH) with the highest median concentration (3570 pg/m(3)). FTOH concentrations were generally similar to previous studies, indicating that in 2014/2015 the impact of the industrial transition had been minor on FTOH levels in indoor air. However, in contrast to earlier studies (with one exception), median concentrations of 6:2 FTOH were higher than 10:2 FTOH. The C8 PFAAs are still the most abundant acids, even though they have now been phased out by major manufacturers. The mean concentrations of FOSE/As, especially MeFOSE (89.9 pg/m(3)), were at least an order of magnitude lower compared to previous studies. Collectively the comparison of FTOHs, PFAAs and FOSE/FOSAs with previous studies indicates that indoor air levels of PFASs display a time lag to changes in production of several years. This is the first indoor air study investigating 6:2 FTMAC, which was frequently detected (58%) and displayed some of the highest maximum concentrations (13 000 pg/m(3)). There were several statistically significant correlations between particular house and room characteristics and PFAS concentrations, most interestingly higher EtFOSE air concentrations in rooms with plastic floors compared to wood or laminate.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

HPLC-MS/MS methods for the determination of 52 perfluoroalkyl and polyfluoroalkyl substances in aqueous samples

Authors: Gremmel, C; Frömel, T; Knepper, TP (2017) Analytical and Bioanalytical Chemistry 409:1643-1655. HERO ID: 3859232

[Less] Two quantitative methods using high-performance liquid chromatography (HPLC) combined with triple quadrupole . . . [More] Two quantitative methods using high-performance liquid chromatography (HPLC) combined with triple quadrupole tandem mass spectrometry (MS/MS) were developed to determine perfluoroalkyl and polyfluoroalkyl substances (PFASs) in aqueous samples. The first HPLC-MS/MS method was applied to 47 PFASs of 12 different substance classes with acidic characteristics such as perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs), as well as precursor substances and biotransformation intermediates (e.g., unsaturated fluorotelomer carboxylic acids). In addition, 25 (13)C-, (18)O-, and (2)H-labeled PFASs were used as internal standards in this method. The second HPLC-MS/MS method was applied to fluorotelomer alcohols (FTOHs) and perfluorooctane sulfonamidoethanols as these compounds have physicochemical properties different from those of the previous ones. Accuracy between 82% and 110% and a standard deviation in the range from 2% to 22% depending on the substances were determined during the evaluation of repeatability and precision. The method quantification limit after solid-phase extraction ranged from 0.3 to 199 ng/L depending on the analyte and matrix. The HPLC-MS/MS methods developed were suitable for the determination of PFASs in aqueous samples (e.g., wastewater treatment plant effluents or influents after solid-phase extraction). These methods will be helpful in monitoring campaigns to evaluate the relevance of precursor substances as indirect sources of perfluorinated substances in the environment. In one exemplary application in an industrial wastewater treatment plant, FTOHs were found to be the major substance class in the influent; in particular, 6:2-FTOH was the predominant compound in the industrial samples and accounted for 74% of the total PFAS concentration. The increase in the concentration of the transformation products of FTOHs in the corresponding effluent, such as fluorotelomer carboxylic acids, unsaturated fluorotelomer carboxylic acids, n:3 polyfluorinated saturated carboxylic acids (n indicates the number of nonfluorinated carbon atoms), and PFCAs, indicated biotransformation of FTOHs or their derivatives during wastewater treatment. However, only 33 mol% of the total amount of PFASs present in the influent was quantified in the corresponding effluent. Graphical abstract Method development of an HPLC-MS/MS multi-method for the determination of PFASs in aqueos samples.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Preparation and characterization of yellowing resistance and low volume shrinkage of fluorinated polysiloxane urethane acrylate

Authors: Ping, Tuo; Zhou, Y; He, Y; Tang, Y; Yang, J; Akram, MY; Nie, Jun (2016) Progress in Organic Coatings 97:74-81. HERO ID: 3857376

[Less] Fluorinated polysiloxane urethane acrylates were synthesized by 1H,1H,2H,2H-Perfluorooctanol (F13), . . . [More] Fluorinated polysiloxane urethane acrylates were synthesized by 1H,1H,2H,2H-Perfluorooctanol (F13), polysiloxane (PSi), isophorone diisocyanate (IPDI) and 2-hydroxyethyl acrylate (HEA). The molecular structure was characterized by FTIR, GPC, and XPS. The yellowing resistance was measured by sphere Spectrophotometer and ultraviolet-visible spectrophotometer. The volume shrinkage was measured by laser displacement sensor (LDS). The glass-transition temperature (Tg) and storage modulus (E') were measured by dynamic mechanical analysis (DMA). Real time infrared (RTIR) spectroscopy was used to investigate the reaction kinetics of photopolymerization of synthesized fluorinated polysiloxane urethane acrylate (PSi-IPDI-HEA-F13). It was proved that the introduced of 1H,1H,2H,2H-Perfluorooctanol into the system of polysiloxane urethane acrylates (PSi-IPDI-HEA) could increase the yellowing resistance and decrease the volume shrinkage. Thermal stability was reduced by a small amount. (C) 2016 Elsevier B.V. All rights reserved.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Engineering artificial communities for enhanced FTOH degradation

Authors: Lewis, M; Kim, MH; Wang, N; Chu, KH (2016) Science of the Total Environment 572:935-942. HERO ID: 3859228

[Less] Fluorotelomer alcohols (FTOHs, [F(CF2)nCH2CH2OH]) are concerned environmental pollutants with perfluorinated . . . [More] Fluorotelomer alcohols (FTOHs, [F(CF2)nCH2CH2OH]) are concerned environmental pollutants with perfluorinated carbon chains. FTOHs can be biotransformed; however, the extent, the pace of the defluorination, and types of metabolites produced vary depending on degradative microorganisms under different environment. In this study, we examined ways to increase the effectiveness of the FTOH defluorination process to less persistent major metabolites. Defined mixed cultures and bioaugmented microbial cultures were engineered to study their ability to biotransform 6:2 fluorotelomer alcohol [F(CF2)6CH2CH2OH]. The effects of carbon sources and the concentration of carbon sources were also examined. All experiments resulted in 5:2 sFTOH [F(CF2)5CH(OH)CH3] as the primary metabolite at the end point. The carbon sources resulted in different amounts of pathway utilization as well as overall changes in effectiveness. The best overall effectiveness was observed when cosubstrate carbon was kept at low concentrations. Pathway II was best utilized by the P. butanovora+P. fluorescens mixed culture, with lactate having a slight negative impact on pathway II utilization. Additional carbon to augmented activated sludge resulted in decreased 6:2 FTOH biotransformation by 60%. Enrichment cultures showed that shorter chain FTOHs are easier to degrade, with the n-octane enriched culture transforming 20% of 8:2 FTOH, 60% of 6:2 FTOH and 70% of 4:2 FTOH. The microbial communities of the enrichment cultures and the alkane hydroxylase gene were also examined to help understand FTOH biotransformation mechanisms.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

Neutral polyfluoroalkyl substances in the atmosphere over the northern South China Sea

Authors: Lai, S; Song, J; Song, T; Huang, Z; Zhang, Y; Zhao, Y; Liu, G; Zheng, J; Mi, W; Tang, J; Zou, S; Ebinghaus, R; Xie, Z (2016) Environmental Pollution 214:449-455. HERO ID: 3359624

[Less] Neutral Polyfluoroalkyl substances (PFASs) in the atmosphere were measured during a cruise campaign . . . [More] Neutral Polyfluoroalkyl substances (PFASs) in the atmosphere were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. Four groups of PFASs, i.e., fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAs), fluorooctane sulfonamides (FOSAs) and fluorooctane sulfonamidoethanols (FASEs), were detected in gas samples. FTOHs was the predominant PFAS group, accounting for 95.2-99.3% of total PFASs (ΣPFASs), while the other PFASs accounted for a small fraction of ΣPFASs. The concentrations of ΣPFASs ranged from 18.0 to 109.9 pg m(-3) with an average of 54.5 pg m(-3). The concentrations are comparable to those reported in other marine atmosphere. Higher concentrations of ΣPFASs were observed in the continental-influenced samples than those in other samples, pointing to the substantial contribution of anthropogenic sources. Long-range transport is suggested to be a major pathway for introducing gaseous PFASs into the atmosphere over the northern SCS. In order to further understand the fate of gaseous PFASs during transport, the atmospheric decay of neutral PFASs under the influence of reaction with OH radicals and atmospheric physical processes were estimated. Concentrations of 8:2 FTOH, 6:2 FTOH and MeFBSE from selected source region to the atmosphere over the SCS after long-range transport were predicted and compared with the observed concentrations. It suggests that the reaction with OH radicals may play an important role in the atmospheric decay of PFAS during long-range transport, especially for shorted-lived species. Moreover, the influence of atmospheric physical processes on the decay of PFAS should be further considered.