Health & Environmental Research Online (HERO)


GenX Chemicals (CASRN 13252-13-6 and CASRN 62037-80-3)


143 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

Development of an oral reference dose for the perfluorinated compound GenX

Authors: Thompson, CM; Fitch, SE; Ring, C; Rish, W; Cullen, JM; Haws, LC (2019) Journal of Applied Toxicology 39:1267-1282. HERO ID: 5381282

[Less] Ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate, also known as GenX, is a processing . . . [More] Ammonium 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)-propanoate, also known as GenX, is a processing aid used in the manufacture of fluoropolymers. GenX is one of several chemistries developed as an alternative to long-chain poly-fluoroalkyl substances, which tend to have long clearance half-lives and are environmentally persistent. Unlike poly-fluoroalkyl substances, GenX has more rapid clearance, but has been detected in US and international water sources. There are currently no federal drinking water standards for GenX in the USA; therefore, we developed a non-cancer oral reference dose (RfD) for GenX based on available repeated dose studies. The review of the available data indicate that GenX is unlikely to be genotoxic. A combination of traditional frequentist benchmark dose models and Bayesian benchmark dose models were used derive relevant points of departure from mammalian toxicity studies. In addition, deterministic and probabilistic RfD values were developed using available tools and regulatory guidance. The two approaches resulted in a narrow range of RfD values for liver lesions observed in a 2-year bioassay in rats (0.01-0.02 mg/kg/day). The probabilistic approach resulted in the lower, i.e., more conservative RfD. The probabilistic RfD of 0.01 mg/kg/day results in a maximum contaminant level goal of 70 ppb. It is anticipated that these values, along with the hazard identification and dose-response modeling described herein, should be informative for risk assessors and regulators interested in setting health-protective drinking water guideline values for GenX.

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

Occurrence and distribution of per- and polyfluoroalkyl substances (PFASs) in the seawater and sediment of the South China sea coastal region

Authors: Wang, Q; Tsui, MMP; Ruan, Y; Lin, H; Zhao, Z; Ku, JPH; Sun, H; Lam, PKS (2019) Chemosphere 231:468-477. HERO ID: 5381284

[Less] Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are anthropogenic chemicals widely used in industrial . . . [More] Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are anthropogenic chemicals widely used in industrial and consumer products. PFASs can be readily transported by water due to their relatively high solubility and polarity, and oceans are believed to be their final global sink. The heavily industrialized and urbanized Pearl River Delta in South China represents a major source of PFASs. In the present study, samples of surface waters, bottom waters, and sediments of the South China Sea (SCS) were collected during summer 2017 and 2018 to determine the level, distribution, and potential regional risk of PFASs. The PFAS concentrations in surface seawater, bottom seawater, and sediment were 125-1015 pg/L, 38-779 pg/L, and 7.5-84.2 pg/g dry weight, respectively. Perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) were the dominant PFASs in seawater, while perfluorooctanesulfonic acid (PFOS) was dominant in sediment. The PFAS alternatives 6:2 and -8:2 Cl-polyfluorinated ether sulfonate (6:2 and 8:2 Cl-PFESA) as well as hexafluoropropylene oxide dimer (HFPO-DA) were detected in the SCS for the first time. The spatial distribution of PFASs in seawater and sediment were impacted by river outflows and sea currents, and concentrations decreased from the estuaries to the offshore regions due to the dilution effect. PFAS concentrations were relatively low compared to other coastal regions worldwide, and a preliminary environmental hazard assessment showed that PFASs posed minimal risk to marine organisms in the coastal region of the SCS, with the exception of PFOS.

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

Electrochemical Oxidation of Hexafluoropropylene Oxide Dimer Acid (GenX): Mechanistic Insights and Efficient Treatment Train with Nanofiltration

Authors: Pica, NE; Funkhouser, J; Yin, Y; Zhang, Z; Ceres, DM; Tong, T; Blotevogel, J (2019) Environmental Science and Technology. HERO ID: 5883625

[Less] Hexafluoropropylene oxide dimer acid (HFPO-DA, trade name GenX) is a perfluoroalkyl ether carboxylic . . . [More] Hexafluoropropylene oxide dimer acid (HFPO-DA, trade name GenX) is a perfluoroalkyl ether carboxylic acid (PFECA) that has been detected in watersheds around the world. Similar to other per- and polyfluoroalkyl substances (PFASs), few processes are able to break HFPO-DA's persistent carbon-fluorine bonds. This study provides both experimental and computational lines of evidence for HFPO-DA mineralization during electrochemical oxidation at a boron-doped diamond anode with a low potential for the generation of stable organofluorine intermediates. Our density functional theory calculations consider the major operative mechanism, direct electron transfer, throughout the entire pathway. Initial oxidative attack does not break the ether bond, but leads to stepwise mineralization of the acidic side chain. Our mechanistic investigations reveal that hydroxyl radicals are unreactive toward HFPO-DA, while electrochemically activated sulfate facilitates its oxidation. Furthermore, we demonstrate that an NF90 membrane is capable of removing 99.5% of HFPO-DA from contaminated water. Electrochemical treatment of the nanofiltration rejectate is shown to reduce both energy and electrode costs by more than 1 order of magnitude compared to direct electrochemical treatment of the raw water. Overall, a nanofiltration-electrochemical oxidation treatment train is a sustainable destructive approach for the cost-effective elimination of HFPO-DA and other PFASs from contaminated water.

Journal Article
Journal Article

Analysis of F-53B, Gen-X, ADONA, and emerging fluoroalkylether substances in environmental and biomonitoring samples: A review

Authors: Munoz, G; Liu, J; Duy, SV; Sauvé, S (2019) Trends in Environmental Analytical Chemistry 23. HERO ID: 5381327

[Less] The persistent, bioaccumulative, and toxic properties of certain per- and polyfluoroalkyl substances . . . [More] The persistent, bioaccumulative, and toxic properties of certain per- and polyfluoroalkyl substances (PFAS) raise concerns for environmental and human health. This has led to the gradual phase-out from production and commerce of some legacy PFAS. Fluoroalkylether compounds (ether-PFAS) are among the fluorinated alternative chemicals that are beginning to be reported in impacted and background environments. Extensive monitoring activities were conducted since 2015–2019 to bridge knowledge gaps on the environmental fate and effects of ether-PFAS including F-53B (6:2 chlorinated polyfluoroalkyl ether sulfonate [6:2 Cl-PFAES] and 8:2 Cl-PFAES), Gen-X (hexafluoropropylene oxide dimer acid [HFPO-DA]), and ADONA (dodecafluoro-3H-4,8-dioxanonanoate). In recent years, advances in nontarget screening using high-resolution mass spectrometry have revealed the identities of other infrequently monitored ether-PFAS. In this critical review, we provide an up-to-date inventory of the structures of ether-PFAS discovered in the recent literature. Their environmental occurrence, fate, and effects are discussed on a comparative perspective with some legacy PFAS such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Information on the methods employed for the quantitative and semi-quantitative analysis of ether-PFAS is also provided, including sample preparation and mass spectrometry analysis, analytical performance, and limitations. In particular, the compiled database of MS/MS fragment ions (n = 111) can be useful in spectrum interpretation of novel ether-PFAS. The concluding remarks open on possible research avenues and the challenges that remain to be addressed.

Technical Report
Technical Report

Annex XV report: Proposal for identification of a substance of very high concern on the basis of the criteria set out in REACH Article 57

Author: ECHA (2019) The Netherlands: ECHA. HERO ID: 5883637

[Less] 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid, its salts and its acyl halides (covering any . . . [More] 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid, its salts and its acyl halides (covering any of their individual isomers and combinations thereof), further denoted as HFPO-DA, are identified as substances of very high concern in accordance with Article 57(f) of Regulation (EC) 1907/2006 (REACH) because in water under environmental conditions these substances exist in the form of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate, for which there is scientific evidence of probable serious effects to the environment and human health which give rise to an equivalent level of concern to those of other substances listed in points (a) to (e) of Article 57 of REACH.

Technical Report
Technical Report

Support document for identification of 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propionic acid, its salts and its acyl halides (covering any of their individual isomers and combinations thereof) as substances of very high concern because of their hazardous properties which cause probable serious effects to human health and the environment which give rise to an equivalent level of concern to those of CMR1 and PBT/vPvB2 substances (article 57f)

Author: ECHA (2019) The Netherlands: ECHA. HERO ID: 5883639


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

Detection of Microbiota in Post Radiation Sinusitis

Authors: Stoddard, TJ; Varadarajan, VV; Dziegielewski, PT; Boyce, BJ; Justice, JM (2019) HERO ID: 5381313

[Less] OBJECTIVES: A shift in the microbiota of chronic rhinosinusitis has been described . . . [More] OBJECTIVES: A shift in the microbiota of chronic rhinosinusitis has been described after radiotherapy to the sinonasal cavity and skull base. There is a paucity of literature characterizing the bacteriology of post radiation sinusitis using next-generation gene sequencing techniques. This study aims to describe and compare the microbial flora of rhinosinusitis after radiotherapy using both culture and molecular techniques for microbial DNA detection.

METHODS: The medical records of patients treated with external beam radiation for sinonasal, nasopharyngeal, or skull base malignancy were reviewed at a tertiary care facility. Patients' sinonasal cavities were swabbed for routine culture or brushed for molecular gene sequencing. Swab specimens were processed for standard microbial culture, and brush specimens were sent for gene sequencing at Micro GenX Laboratory (Lubbock, Texas, USA).

RESULTS: Twenty-two patients were diagnosed with chronic sinusitis after undergoing radiotherapy. Staphylococcus aureus was the most common organism identified by both culture and gene sequencing, followed by Pseudomonas aeruginosa. Several additional organisms were detected by gene sequencing that were not isolated by routine culture techniques. Gene sequencing identified pathogens differing from culture results in 50% of patients examined.

CONCLUSION: The bacteriology of post radiation sinusitis appears to resemble the microorganisms responsible for chronic sinusitis in healthy adults. Next generation gene sequencing techniques may reveal additional organisms responsible for sinusitis and provide complementary results that may impact the medical treatment of post radiation sinusitis.

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

Efficient removal of GenX (HFPO-DA) and other perfluorinated ether acids from drinking and recycled waters using anion exchange resins

Authors: Dixit, F; Barbeau, B; Mostafavi, SG; Mohseni, M (2019) HERO ID: 5883626

[Less] Carcinogenic GenX chemicals, heptafluoropropylene-oxide-dimer-acid (HFPO-DA), have been recently detected . . . [More] Carcinogenic GenX chemicals, heptafluoropropylene-oxide-dimer-acid (HFPO-DA), have been recently detected in surface, ground and recycled water sources worldwide. However, GenX removals under the influence of variable characteristics of the organic and inorganic compounds present in the natural water sources, have often been overlooked in scientific literature. This is critically important given that the ionic composition and characteristics of organic matter in natural waters are spatially and seasonally variable. A strongly basic anion exchange (IX) resin was used to remove GenX and two other perfluorinated ether acids (PFEAS) from natural surface and recycled water sources. Factors influencing the uptake behavior included the PFEAS concentrations, resin dosage, and background anion characteristics. The equivalent background compound was employed to evaluate the competitive uptake between natural organic matter (NOM), inorganic ions and PFEAS in natural water matrices. Experimental data were compared with different mathematical and physical models and it was depicted that approximately 4-6% of the initial NOM competed with PFEAS for active exchange sites. Further, IX was able to achieve complete PFEAS removal (Cfinal<10 ng/L) with simultaneous removal of>60% NOM and >80% inorganic ions. Results of this study indicate that IX exhibits great potential for PFEAS removal from natural drinking water sources.

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

Analysis of hexafluoropropylene oxide-dimer acid (HFPO-DA) by Liquid Chromatography-Mass Spectrometry (LC-MS): Review of Current Approaches and Environmental Levels

Authors: Mullin, L; Katz, D; Riddell, N; Plumb, R; Burgess, JA; Yeung, LWY; Jogsten, IE (2019) HERO ID: 5883629

[Less] Emerging per- and polyfluorinated compounds (PFAS) compounds are of increasing interest for environmental . . . [More] Emerging per- and polyfluorinated compounds (PFAS) compounds are of increasing interest for environmental monitoring, one being hexafluoropropylene oxide-dimer acid (HFPO-DA), commonly referred to as GenX. The following review describes existing liquid chromatography-mass spectrometry (LC-MS) methods used to analyze HFPO-DA, including sample preparation and method sensitivity relative to other PFAS. Analytical challenges are also described, in particular the significant formation of in-source fragmentation, dimer and dimer adducts which detract from [M-H]- signal. Lastly, detected levels of HFPO-DA in environmental and biological samples are compared across the limited number of available field exposure studies, which found several μg/L concentrations in water samples taken near fluorochemical plant discharges.

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

Enhanced host-guest complexation of short chain perfluoroalkyl substances with positively charged beta-cyclodextrin derivatives

Authors: Weiss-Errico, MJo; O'Shea, KE (2019) HERO ID: 5883630