Health & Environmental Research Online (HERO)


PFHxA (307-24-4)


212 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

Spatial and temporal trends in perfluorooctanoic and perfluorohexanoic acid in well, surface, and tap water around a fluoropolymer plant in Osaka, Japan

Authors: Shiwaku, Y; Lee, P; Thepaksorn, P; Zheng, B; Koizumi, A; Harada, KH (2016) Chemosphere 164:603-610. HERO ID: 3859737

[Less] This study was conducted to clarify the spatial distributions of perfluorooctanoic acid (PFOA) and perfluorohexanoic . . . [More] This study was conducted to clarify the spatial distributions of perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) in well, surface and tap water around a fluoropolymer plant in Osaka between 2003 and 2016 and to predict the fate of those chemicals in these aquatic environments. We analyzed 44 well, six surface and six tap water samples collected within a 5 km radius of the plant. The PFOA concentrations in well water ranged from 45.2 to 7440 ng/L (median = 240 ng/L), while PFHxA concentrations ranged from 9.68 to 970 (median = 45.4 ng/L) in 2015-2016. The concentration of other perfluoroalkyl carboxylic acids were lower than PFOA and PFHxA in well water. Fixed-point observation showed that the levels of PFOA decreased greatly over the last few decades, whereas those of PFHxA increased in both well and surface water. Further monitoring and investigation are suggested to understand PFOA and PFHxA contamination and fate in the environment, as well as their potential for human exposure in this region.

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

Residual organic fluorinated compounds from thermal treatment of PFOA, PFHxA and PFOS adsorbed onto granular activated carbon (GAC)

Authors: Watanabe, N; Takemine, S; Yamamoto, K; Haga, Y; Takata, M (2016) HERO ID: 3859930

[Less] Perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA) and perfluorooctane sulfonate (PFOS) adsorbed . . . [More] Perfluorooctanoic acid (PFOA), perfluorohexanoic acid (PFHxA) and perfluorooctane sulfonate (PFOS) adsorbed onto granular activated carbon (GAC) were thermally treated in N-2 gas stream. The purpose was to assess the fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) during thermal regeneration of GAC, which had been used for water treatment. Mineralized F, residual PFASs including short-chained species, and volatile organic fluorine (VOF) were determined. In a temperature condition of 700 A degrees C, VOF were 13.2, 4.8, and 5.9 % as for PFOA, PFHxA, and PFOS. However, the VOF decreased to 0.1 %, if the GAC and off-gas were kept at 1000 A degrees C. No PFASs remained in GAC at 700-1000 A degrees C; at the same time, short-chained PFASs were slightly detected in the aqueous trapping of off-gas at 800 and 900 A degrees C conditions. The destruction of PFASs on GAC could be perfect if the temperature is higher than 700 A degrees C; however, the process is competitive against volatile escape from GAC. Destruction in gaseous phase needs a temperature as high as 1000 A degrees C. Destruction of PFASs on the surface of GAC, volatile escape from the site, and thermolysis in gas phase should be considered, as to thermal regeneration of GAC.

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 perfluoroalkyl substances (PFASs) in surface water and bottom water of the Shuangtaizi Estuary, China

Authors: Shao, M; Ding, G; Zhang, J; Wei, L; Xue, H; Zhang, N; Li, Y; Chen, G; Sun, Y (2016) Environmental Pollution 216:675-681. HERO ID: 3856470

[Less] Perfluoroalkyl substances (PFASs) have been recognized as emerging environmental pollutants. However, . . . [More] Perfluoroalkyl substances (PFASs) have been recognized as emerging environmental pollutants. However, there is limited information on the contamination level and spatial distribution of PFASs in the Shuangtaizi Estuary, where the Shuangtaizi Hekou Nature Reserve is located. In the present study, the contamination level and spatial distribution of PFASs in surface water (approximately 0.5 m below the surface) and bottom water (about 0.5 m above the bottom) of the Shuangtaizi Estuary were investigated. The data indicated that the Shuangtaizi Estuary was commonly contaminated by PFASs. The total concentration of PFASs in surface and bottom water of the Shuangtaizi Estuary ranged from 66.2 to 185 ng L(-1) and from 44.8 to 209 ng L(-1), respectively. The predominant PFASs were perfluorobutanoic acid (PFBA), perfluoropentanoic acid, perfluorooctanoic acid, perfluorohexanoic acid and perfluorobutane sulfonate (PFBS). In general, PFAS concentrations in surface water samples were lower than those in bottom water samples. The spatial distribution of PFASs in the Shuangtaizi Estuary was mainly affected by particular landform, tide and residual currents in Liaodong Bay. The total mass flux of 15 PFASs from the Shuangtaizi River to Liaodong Bay was estimated to be 352 kg year(-1), which was lower than the total flux from the Daling River and the Daliao River. As short-chain PFASs, such as PFBS and PFBA, have been the prevalent compounds in some places and are continuously produced and used, long-term monitoring and effective pollution controls are suggested.

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

Aerobic biotransformation of polyfluoroalkyl phosphate esters (PAPs) in soil

Authors: Liu, C; Liu, J (2016) Environmental Pollution 212:230-237. HERO ID: 3856871

[Less] Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) . . . [More] Microbial transformation of polyfluoroalkyl phosphate esters (PAPs) into perfluorocarboxylic acids (PFCAs) has recently been confirmed to occur in activated sludge and soil. However, there lacks quantitative information about the half-lives of the PAPs and their significance as the precursors to PFCAs. In the present study, the biotransformation of 6:2 and 8:2 diPAP in aerobic soil was investigated in semi-dynamics reactors using improved sample preparation methods. To develop an efficient extraction method for PAPs, six different extraction solvents were compared, and the phenomenon of solvent-enhanced hydrolysis was investigated. It was found that adding acetic acid could enhance the recoveries of the diPAPs and inhibit undesirable hydrolysis during solvent extraction of soil. However 6:2 and 8:2 monoPAPs, which are the first breakdown products from diPAPs, were found to be unstable in the six solvents tested and quickly hydrolyzed to form fluorotelomer alcohols. Therefore reliable measurement of the monoPAPs from a live soil was not achievable. The apparent DT50 values of 6:2 diPAP and 8:2 diPAP biotransformation were estimated to be 12 and > 1000 days, respectively, using a double first-order in parallel model. At the end of incubation of day 112, the major degradation products of 6:2 diPAP were 5:3 fluorotelomer carboxylic acid (5:3 acid, 9.3% by mole), perfluoropentanoic acid (PFPeA, 6.4%) and perfluorohexanoic acid (PFHxA, 6.0%). The primary product of 8:2 diPAP was perfluorooctanoic acid (PFOA, 2.1%). The approximately linear relationship between the half-lives of eleven polyfluoroalkyl and perfluoroalkyl substances (PFASs, including 6:2 and 8:2 diPAPs) that biotransform in aerobic soils and their molecular weights suggested that the molecular weight is a good indicator of the general stability of low-molecular-weight PFAS-based compounds in aerobic soils.

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

Use of Fenton reagent combined with humic acids for the removal of PFOA from contaminated water

Authors: Santos, A; Rodríguez, S; Pardo, F; Romero, A (2016) Science of the Total Environment 563-564:657-663. HERO ID: 3858272

[Less] Perfluorinated compounds (PFCs) are receiving significant attention due to its global distribution, . . . [More] Perfluorinated compounds (PFCs) are receiving significant attention due to its global distribution, high persistence, and bioaccumulation properties. Among them, perfluorooctanoic acid (PFOA) is one of the most commonly found in the environment. The strong bond C-F in PFOA is extremely difficult to degrade, therefore advanced oxidation processes (AOPs) at room temperature and pressure are not able to oxidize them, as was noticed here using Fenton like reagent (FR) or persulfate (PS) at 25°C. On the contrary, by using persulfate activated by heat (100mM and T=70°C) a complete defluorination of PFOA 0.1mM was noticed after 18h, with a sequential degradation mechanism of losing one CF2 unit from PFOA and its intermediates (perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPA) and perfluorobutanoic acid (PFBA)). Since this thermal treatment is not usually desirable from an economical point of view, alternative process has been tested. For this scope, a hybrid process is proposed in this work, by adding humic acid, HA, (600mgL(-1)) and FR, (165mM in H2O2 and 3mM in Fe(3+)) to the 0.1mM PFOA solution. It was found that the HA was oxidized by FR. PFOA was entrapped quantitatively and irreversibly during HA oxidation, resulting PFOA non-available to the aqueous phase. Oxidized HA with PFOA entrapped precipitates. Both, the leftover Fe(III) acting as a coagulant and neutral pH enhance the separation of this solid phase. The precipitation noticed by adding HA to the PFOA solution in absence of FR was negligible.

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

Elevated levels of short carbon-chain PFCAs in breast milk among Korean women: Current status and potential challenges

Authors: Kang, H; Choi, K; Lee, HS; Kim, DH; Park, NY; Kim, S; Kho, Y (2016) Environmental Research 148:351-359. HERO ID: 3859603

[Less] Breast milks can be contaminated with perfluoroalkyl substances (PFASs). Exposure to PFASs during early . . . [More] Breast milks can be contaminated with perfluoroalkyl substances (PFASs). Exposure to PFASs during early stages of life may lead to adverse health effects among breastfed infants. To date, perfluorootanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been most frequently measured PFASs in breast milks worldwide. Information on shorter carbon-chain PFASs in breast milk is scarce. In this study, breast milks were sampled from 264 Korean lactating women, and measured for seventeen PFASs, including ten perfluoroalkyl carboxylates (PFCAs), four perfluoroalkyl sulfonates, and three perfluoroalkyl sulfonamides. PFOA and PFOS were detected in 98.5% of the breast milk samples, with median concentrations of 0.072 and 0.050ng/mL, respectively. Perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), and perfluoroheptanoic acid (PFHpA) were detected in higher frequencies, ranging between 67.4% and 81.8%. The concentrations of short carbon-chain PFCAs in breast milk such as PFPeA and PFHxA were the highest ever reported to date, and were comparable to that of PFOS. Concentrations of shorter chain PFCA in breast milk tended to be higher among the women with longer lactation period, while those of PFOA showed the opposite trend, suggesting a possibility that breastfeeding might be an important route of excretion for PFOA among lactating women. Fish consumption and the use of consumer products, e.g., skin care products, cosmetics and non-stick coated cooking utensils, were identified as significant predictors of PFAS concentrations in breast milk. Health risks associated with PFOA and PFOS exposure through breastfeeding were estimated negligible, however, risks of the short carbon-chain PFCAs could not be assessed because of lack of relevant toxicological information. Further efforts for source identification and exposure management measures for shorter chain PFCAs are necessary.

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

Thermodynamic Study of Aggregation of Cholinium Perfluoroalkanoate Ionic Liquids

Authors: Florindo, C; Tome, LC; Marrucho, IM (2016) HERO ID: 3859910

[Less] To advance the ionic liquid (IL) platform to tailor fluorinated surfactant properties, the aim of this . . . [More] To advance the ionic liquid (IL) platform to tailor fluorinated surfactant properties, the aim of this work is to evaluate the surfactant properties of cholinium-based salts bearing perfluoroalkanoate anions. Novel surfactant ILs containing the cholinium cation [Ch](+) combined with different perfluoroalkanoate anions, namely perfluoropentanoate [PFPent](-), perfluorohexanoate [PFHex](-), perfluoroheptanoate [PFHept](-), and perfluorooctanoate [PFOct](-), were synthesized. The critical micelle concentrations (CMCs) were determined using an ionic conductivity method, at different temperatures. Thermodynamic parameters of micellization were also evaluated. The results indicate that the CMC value decreases in a linear manner with the increment of the fluoroalkyl chain length in the anion. The evaluation of the thermodynamic parameters shows that the micellization is spontaneous and entropically driven and that the enthalpy of micellization is very small. It was also observed that the introduction of the cholinium cation in these surfactants allows for smaller CMC values when compared to that of other tetraalkylammonium-based surfactants with the same fluorinated anions, in short to more efficient and green surfactants. This result is probably due to counterion association and not to counterion binding to micelle surface.

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 in Daliao River system of northeast China: determination, distribution and ecological risk

Authors: Gong, X; Liu, R; Li, Bin; Song, Y; Liu, Y (2016) Environmental Earth Sciences 75. HERO ID: 3858922

[Less] Perfluoroalkyl acids (PFAAs) in Daliao River system were simultaneously determined by UPLC-MS/MS coupled . . . [More] Perfluoroalkyl acids (PFAAs) in Daliao River system were simultaneously determined by UPLC-MS/MS coupled with SPE for water samples and with ultrasonication extraction for sediments. All samples were collected from the mainstreams of Hun River (HR) and Daliao River (DLR), as well as urban canal Xi River (XR) in Shenyang City, located in northeast China. Under the optimal conditions, the recoveries of most selected PFAAs were 61-131 % with RSD below 30 % for spiked water and sediment samples. The total average concentrations of PFAAs in surface water were 1.76-9.47 ng/L in the HR, 9.54-13.0 ng/L in the DLR and 33.5-50.7 ng/L in the XR. As the dominant PFAAs, perfluorooctanoic acid (PFOA) was detected at levels from 1.52 to 7.12 ng/L in the HR and DLR. PFOA, perfluoropentanoic acid (PFPA) and perfluorooctane sulfonic acid (PFOS) were the most abundant compounds detected in the XR with concentration ranges of 6.71-18.1, 9.7-26 and 0.81-13 ng/L, respectively. The average concentration of PFAAs in the sediments followed the sequence of the XR > DLR > HR. Perfluorodecanoic acid (PFHxA) was the dominant PFAA detected in 76.5 % of the sediment samples from the three rivers, with the concentrations of 0.07-0.49 ng/g dry mass. Both PFOS and PFOA were measurable in the sediments on very few occasions, with the concentration up to 0.84 ng/g dry mass. The calculated average partition coefficients (Log K-d, L/kg) of PFOA and PFOS between the sediment and water were 1.18 and 2.21, respectively. Given their exposure levels and risk quotient (RQ) values, PFOS and PFOA had no significant risk to aquatic organisms in the DLR system.

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

Transformation of polyfluorinated compounds in natural waters by advanced oxidation processes

Authors: Anumol, T; Dagnino, S; Vandervort, DR; Snyder, SA (2016) Chemosphere 144:1780-1787. HERO ID: 3859278

[Less] The presence of perfluorocarboxylic acids (PFCAs) in source and finished drinking waters is a concern . . . [More] The presence of perfluorocarboxylic acids (PFCAs) in source and finished drinking waters is a concern with studies showing bioaccumulation and adverse toxicological effects in wildlife and potentially humans. Per/Polyfluoroalkyl substances (PFAS) such as fluorotelomer alcohols have been identified as precursors for PFCAs in biological pathways. In this study, we investigated the fate of 6:2 and 8:2 homologues of the fluorotelomer unsaturated carboxylic acids (FTUCAs) during advanced oxidation process (AOPs). Results showed 6:2 FTUCA and 8:2 FTUCA transformed into 6-C PFCA (PFHxA) and 8-C PFCA (PFOA) respectively with very little other PFCA formation for all AOPs. The degradation of 6:2 FTUCA and 8:2 FTUCA was greater in the GW compared to SW for the ozone processes but similar for UV/H2O2. The formation of n-C PFCA followed O3>O3/H2O2 at same dose and UV/H2O2 had much lower formation at the doses tested. Non-targeted analysis with the LC-MS-qTOF indicated the production of other PFCAs which contribute to the total mass balance, although no intermediate product was discovered indicating a rapid and direct transformation from the FTUCAs to the PFCAs and/or significant volatilization of intermediates. With the use of AOPs essential to water reuse treatment schemes, this work raises concerns over the risk of potential formation of PFCAs in the treatment and their adverse health effects in finished drinking water.

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

Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing

Authors: Holmquist, H; Schellenberger, S; van der Veen, I; Peters, GM; Leonards, PE; Cousins, IT (2016) Environment International 91:251-264. [Review] HERO ID: 3859922

[Less] Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry . . . [More] Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (includes dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regards to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellence of non-fluorinated alternatives. It also shows that for all alternatives, impurities and/or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the environment and human health.