Health & Environmental Research Online (HERO)


PFHxA (307-24-4)


249 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

The use of carbon adsorbents for the removal of perfluoroalkyl acids from potable reuse systems

Authors: Inyang, M; Dickenson, ERV (2017) Chemosphere 184:168-175. HERO ID: 3858250

[Less] Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing . . . [More] Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing perfluoroalkyl acids (PFAA) from field waters, compared to granular activated carbon (GAC). Screening tests using organic matter-free water resulted in hardwood (HWC) (Kd = 41 L g(-1)) and pinewood (PWC) (Kd = 49 L g(-1)) biochars having the highest perfluorooctanoic acid (PFOA) removal performance that was comparable to bituminous coal GAC (Kd = 41 L g(-1)). PWC and HWC had a stronger affinity for PFOA sorbed in Lake Mead surface water (KF = 11 mg((1-n)) L(n) g(-1)) containing a lower (2 mg L(-1)) dissolved organic carbon (DOC) concentration than in a tertiary-filtered wastewater (KF = 8 mg((1-n)) L(n) g(-1)) with DOC of 4.9 mg L(-1). A pilot-scale study was performed using three parallel adsorbers (GAC, anthracite, and HWC biochar) treating the same tertiary-filtered wastewater. Compared to HWC, and anthracite, GAC was the most effective in mitigating perfluoropentanoic acid (PFPnA), perfluorohexanoic acid (PHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and DOC (45-67% removed at 4354 bed volumes) followed by HWC, and then anthracite. Based on bench- and pilot-scale results, shorter-chain PFAA [perfluorobutanoic acid (PFBA), PFPnA, or PFHxA] were more difficult to remove with both biochar and GAC than the longer-chain, PFOS and PFOA.

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

Tissue toxicokinetics of perfluoro compounds with single and chronic low doses in male rats

Authors: Iwabuchi, K; Senzaki, N; Mazawa, D; Sato, I; Hara, M; Ueda, F; Liu, W; Tsuda, S (2017) Journal of Toxicological Sciences 42:301-317. HERO ID: 3859701

[Less] To examine the kinetics of low doses of perfluoro compounds (PFCs), we administered perfluorohexanoic . . . [More] To examine the kinetics of low doses of perfluoro compounds (PFCs), we administered perfluorohexanoic acid (C6A), perfluorooctanoic acid (C8A), perfluorononanoic acid (C9A) and perfluorooctane sulfonate (C8S) with a single oral dose (50-100 μg/kg BW), and in drinking water at 1, 5, and 25 μg/L for one and three months to male rats; and examined the distribution in the brain, heart, liver, spleen, kidney, whole blood and serum. C6A was very rapidly absorbed, distributed and eliminated from the tissues with nearly the same tissue t1/2 of 2-3 hr. Considering serum Vd, and the tissue delivery, C6A was mainly in the serum with the lowest delivery to the brain; and no tissue accumulation was observed in the chronic studies as estimated from the single dose study. For the other PFCs, the body seemed to be an assortment of independent one-compartments with a longer elimination t1/2 for the liver than the serum. The concentration ratio of liver/serum increased gradually from C0 to a steady state. The high binding capacity of plasma protein may be the reason for the unusual kinetics, with only a very small fraction of free PFCs moving gradually to the liver. Although the tissue specific distribution was time dependent and different among the PFCs, the Vd and ke of each tissue were constant throughout the study. The possibility of extremely high C6A accumulation in the human brain and liver was suggested, by comparing the steady state tissue concentration of this study with the human data reported by Pérez et al. (2013).

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

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

Footprints of urban micro-pollution in protected areas: Investigating the longitudinal distribution of perfluoroalkyl acids in wildlife preserves

Authors: Rodriguez-Jorquera, IA; Silva-Sanchez, C; Strynar, M; Denslow, ND; Toor, GS (2016) PLoS ONE 11:e0148654. HERO ID: 3448334

[Less] Current approaches to protect biodiversity by establishing protected areas usually gloss over water . . . [More] Current approaches to protect biodiversity by establishing protected areas usually gloss over water pollution as a threat. Our objective was to determine the longitudinal and seasonal distribution of perfluoroalkyl acids (PFAAs) in water column and sediments from a wastewater dominated stream that enters preservation areas. Water samples were collected along the longitudinal section (six sites, 1000 m away from each other) of the stream during the dry and wet seasons. Sediments were collected from three sites along the stream from three depths. Water and sediments were analyzed for PFAAs using high performance liquid chromatography-tandem mass spectrometry. Eleven PFAAs with 5 to 14 carbon atoms were detected in the water column at all sampling points, with a minor reduction at the last point suggesting a dilution effect. The most detected PFAAs was PFOS, followed by perfluorooctanoic acid (PFOA), and perfluorohexanoic acid (PFHxA). Seasonal differences in PFAAs concentrations suggested contribution of stormwater runoff during the wet season. All analyzed PFAAs in sediments were under the limit of quantification, likely due to the high proportion of sand and low organic matter. However, high concentrations of PFAAs were detected in the water column inside the protected areas, which includes PFOS in concentrations considered not safe for avian wildlife. Water samples appear to be more relevant than sediments to determine PFAAs micro-pollution in water bodies with sandy sediments. Inclusion of a management plans on micro-pollution research, monitoring, and mitigation is recommended for protected areas.

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) 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.

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

Biotransformation potential of 6:2 fluorotelomer sulfonate (6:2 FTSA) in aerobic and anaerobic sediment

Authors: Zhang, S; Lu, X; Wang, N; Buck, RC (2016) Chemosphere 154:224-230. HERO ID: 3857383

[Less] Aqueous film-forming foam (AFFF) products are used in industrial and military firefighting around the . . . [More] Aqueous film-forming foam (AFFF) products are used in industrial and military firefighting around the globe. These products contain fluoroalkylthioamido sulfonates, fluoroalkylthiobetaine, and other related substances as the major ingredients, which can be biotransformed in the environment to form 6:2 fluorotelomer sulfonate (6:2 FTSA, F(CF2)6CH2CH2SO3-) as one of the major initial biotransformation products. Limited information is available on 6:2 FTSA aerobic biotransformation in activated sludge and pure microbial culture. This is the first study to report 6:2 FTSA biotransformation in aerobic and anaerobic sediment. 6:2 FTSA was rapidly biotransformed in aerobic river sediment with a half-life less than 5 d. Major stable transformation products observed after 90 d included 5:3 Acid [F(CF2)5CH2CH2COOH), 16 mol%), PFPeA [F(CF2)4COOH, 21 mol%] and PFHxA (F(CF2)5COOH, 20 mol%). 6:2 fluorotelomer alcohol [6:2 FTOH, F(CF2)6CH2CH2OH] was readily biotransfomed whereas 6:2 FTSA biotransformation did not occur in anaerobic sediment over 100 d, indicating that the enzymatic desulfonation step limited 6:2 FTSA biotransformation in anaerobic sediment. These results suggest that 6:2 FTSA related products, after release to the aerobic environment, is likely to biodegrade forming 5:3 Acid, PFPeA and PFHxA. This study also indicates that 6:2 FTSA formed from its aforementioned precursors may be persistent in the anaerobic environment after their potential release. This work provides insight to understanding the fate and environmental loading of AFFF-related products and their major transformation products 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

[Residue Characteristics of Perfluorinated Compounds in the Atmosphere of Shenzhen]

Authors: He, PF; Zhang, H; Li, J; He, L; Luo, J; Liu, GQ; Shen, JC; Yang, B; Cui, XY (2016) Huanjing Kexue / Chinese Journal of Environmental Science 37:1240-1247. HERO ID: 3859277

[Less] In order to explore the residual characteristics of perfluorinated compounds (PFCs) in the atmosphere . . . [More] In order to explore the residual characteristics of perfluorinated compounds (PFCs) in the atmosphere of Shenzhen, passive air samplers consisting of polyurethane foam (PUF) disks impregnated with XAD-4 power were deployed at 12 sites in Shenzhen from November 2014 to February 2015. Seven volatile and fifteen ionic PFCs were analyzed. The results indicated that ΣPFCs concentration ranged from 23.7 pg x m(-3) to 157 pg x m(-3) (mean: 79.0 pg x m(-3)), dominated by volatile PFCs, with 8:2 FTOITI, 6:2 FTOH, PFPeA, PFOA being the dominant compounds. The spatial distribution of volatile and ionic PFCs concentrations was the same, displaying the characteristic of "the northwest being higher than the southeast ". Furthermore, the concentrations of 6:2 FTOHs, 8:2 FTOHs, PFPeA, PFHxA and PFOA had positive correlations with PM2.5 and PM10 (P < 0.05, P < 0.01) and were more positively correlated with the levels of PM10 than those of PM2.5.

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.