Health & Environmental Research Online (HERO)


PFHxA (307-24-4)


327 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

Perfluorohexanoic acid toxicity, part I: Development of a chronic human health toxicity value for use in risk assessment

Authors: Luz, AL; Anderson, JK; Goodrum, P; Durda, J (2019) Regulatory Toxicology and Pharmacology 103:41-55. HERO ID: 5080589

[Less] Perfluorohexanoic acid (PFHxA) is a short-chain, six-carbon perfluoroalkyl acid (PFAA) and is a primary . . . [More] Perfluorohexanoic acid (PFHxA) is a short-chain, six-carbon perfluoroalkyl acid (PFAA) and is a primary impurity, degradant, and metabolite associated with the short-chain fluorotelomer-based chemistry used globally today. The transition to short-chain fluorotelomer-based products as a cornerstone in replacement fluorochemistry has raised questions regarding potential human health risks associated with exposure to fluorotelomer-based substances and therefore, PFHxA. Here, we present a critical review of data relevant to such a risk assessment, including epidemiological studies and in vivo and in vitro toxicity studies that examined PFHxA acute, subchronic, and chronic toxicity. Key findings from toxicokinetic and mode-of-action studies are also evaluated. Sufficient data exist to conclude that PFHxA is not carcinogenic, is not a selective reproductive or developmental toxicant, and does not disrupt endocrine activity. Collectively, effects caused by PFHxA exposure are largely limited to potential kidney effects, are mild and/or reversible, and occur at much higher doses than observed for perfluorooctanoic acid (PFOA). A chronic human-health-based oral reference dose (RfD) for PFHxA of 0.25 mg/kg-day was calculated using benchmark dose modeling of renal papillary necrosis from a chronic rat bioassay. This RfD is four orders of magnitude greater than the chronic oral RfD calculated by the U.S. Environmental Protection Agency for PFOA. The PFHxA RfD can be used to inform public health decisions related to PFHxA and fluorotelomer precursors for which PFHxA is a terminal degradant. These findings clearly demonstrate that PFHxA is less hazardous to human health than PFOA. The analyses presented support site-specific risk assessments as well as product stewardship initiatives for current and future short-chain fluorotelomer-based products.

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 paired serum, urine, and hair samples: Correlations with demographic factors and dietary habits

Authors: Kim, DH; Lee, JH; Oh, JE (2019) Environmental Pollution 248:175-182. HERO ID: 5080622

[Less] We analyzed paired serum, urine, and hair samples from 94 Korean children and adults to investigate . . . [More] We analyzed paired serum, urine, and hair samples from 94 Korean children and adults to investigate levels of 11 perfluoroalkyl acids (PFAAs). The effects of demographic factors and dietary habits on PFAA exposure were also assessed based on the paired samples. The total PFAA concentrations were 2.4-31 ng/mL in serum, not detected-9.5 ng/mL in urine, and 0.48-15 ng/g in hair. Levels of perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), which have short carbon chains, were 1.5-5 fold higher in urine and hair than in serum. The PFAA concentrations in serum exhibited a decreasing trend with age from young childhood to adolescence, followed by an increasing trend after adolescence. For most PFAA species, concentrations in serum were higher in adult males than in adult females (p < 0.01). No sex difference was evident in the urine and hair samples. In addition, there was no age difference in the urine samples, but in the hair samples, we observed higher concentrations of PFAAs in children than in the other age groups (p < 0.01). The consumption rates of fish and water showed significant correlations with serum (positive correlation) and hair (negative) concentrations, respectively. No relationships between serum and hair/urine levels for most PFAAs were observed, except between serum and hair levels for perfluorooctanoic acid (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

Perfluoroalkyl acids in drinking water of China in 2017: Distribution characteristics, influencing factors and potential risks

Authors: Li, Y; Li, J; Zhang, L; Huang, Z; Liu, Y; Wu, N; He, J; Zhang, Z; Zhang, Y; Niu, Z (2019) Environment International 123:87-95. HERO ID: 5080645

[Less] Perfluoroalkyl acids (PFAAs) are a group of emerging persistent organic pollutants (POPs), which have . . . [More] Perfluoroalkyl acids (PFAAs) are a group of emerging persistent organic pollutants (POPs), which have been ubiquitously detected in the environmental media. However, national scale investigations on their occurrence and distribution in drinking water are still insufficient. In this study, we detected the 17 priority PFAAs in drinking water from 79 cities of 31 provincial-level administrative regions throughout China, and investigated their occurrence and distribution. Additionally, we also analyzed the influencing factors on their profiles, such as the existence of industrial sources, socioeconomic factors (population density and GDP), and assessed levels of risk associated with contaminated drinking water. On the national scale, the sum concentrations of the 17 PFAAs (∑17PFAAs) in drinking water was in a range of 4.49-174.93 ng/L with a mean value of 35.13 ng/L. Among the 17 individual PFAAs, perfluorobutanoic acids (PFBA) was the most abundant individual PFAAs with the median concentration of 17.87 ng/L, followed by perfluorooctanoic acid (PFOA, 0.74 ng/L), perfluorononanoic acid (PFNA, 0.40 ng/L) and perfluorooctane sulfonic acid (PFOS, 0.25 ng/L). The geographic distribution characteristic of ∑17PFAAs in drinking water was in a descending order of Southwestern China (57.67 ng/L) > Eastern coastal China (32.85 ng/L) > Middle China (29.89 ng/L) > Northwestern China (28.49 ng/L) > Northeastern China (22.03 ng/L), and in general, the existence of the industrial sources could positively affect the contamination levels of PFAAs in drinking water. The pollution level of PFAAs in drinking water also varied among the three different city levels (medium-sized city > big city > town). In towns, the positive correlations were observed between the population density and the ∑17PFAAs (R2 = 0.45, p < 0.01), and the individual concentration of PFHxA, PFBS, and PFOA (p < 0.01). Moreover, besides PFAAs in Yunnan, Jiangsu, and Jiangxi, concentrations of related PFAAs in drinking water from 28 provinces were less than the suggested drinking water advisories. The relatively higher concentrations of PFAAs in Yunnan, Jiangsu, and Jiangxi suggest that further studies focusing on their sources and potential health risk to humans are needed.

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

Subtle morphometric, behavioral and gene expression effects in larval zebrafish exposed to PFHxA, PFHxS and 6:2 FTOH

Authors: Annunziato, KM; Jantzen, CE; Gronske, MC; Cooper, KR (2019) Aquatic Toxicology 208:126-137. HERO ID: 5080590

[Less] Recent studies of perfluoroalkylated substances (PFASs) have focused on the toxicity of long chain PFASs, . . . [More] Recent studies of perfluoroalkylated substances (PFASs) have focused on the toxicity of long chain PFASs, such as PFOS or PFOA, which have been demonstrated to cause an array of developmental and behavioral effects. However, less is known about low molecular weight PFASs and alternatives. This study examined the morphometric and behavioral effects in zebrafish following developmental exposures of C6 PFASs: perfluorohexanoic acid, PFHxA, perfluorohexane sulfonate, PFHxS, and 6:2 fluorotelomer alcohol, 6:2 FTOH. Embryos were exposed to 0.02-20 μM concentrations of these compounds from the high stage (˜3 h post fertilization, hpf) until 120 hpf. Morphometric and gene expression endpoints were examined at 120 hpf. Genes selected for analysis were previously shown to be altered in zebrafish developmentally exposed to PFOS and PFOA. Additionally, exposed larvae were transferred to clean water and reared until 14 days post fertilization, dpf, when behavioral assays were completed and morphometric endpoints examined. While PFHxA was found to be the most acutely toxic at 120 hpf, few morphometric effects were observed. Gene expression was the most sensitive endpoint with significant increased tgfb1a, bdnf, and ap1s1 expression observed with PFHxA exposure. PFHxS exposure produced morphometric effects in the larvae, specifically increased length and yolk sac area at 2 and 20 μM. This phenotype persisted to the 14 dpf time point, where these larvae additionally displayed decreased distance traveled and crosses through the center of the arena of the behavioral assay. Exposure to 6:2 FTOH caused no morphometric effects at 120 hpf, and this compound was the least acutely toxic. However, expression of both tgfb1a and bdnf were increased by greater than 2 fold change at this time point. Effects also persisted to 14 dpf where a significant increase in distance traveled and velocity were observed in the behavioral assay. This study demonstrates effects on behavioral, morphometric and gene expression endpoints with developmental PFHxA, PFHxS, and 6:2 FTOH exposures in zebrafish.

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 of perfluorinated compounds in agricultural environment, vegetables, and fruits in regions influenced by a fluorine-chemical industrial park in China

Authors: Li, P; Oyang, X; Zhao, Y; Tu, T; Tian, X; Li, L; Zhao, Y; Li, J; Xiao, Z (2019) Chemosphere 225:659-667. HERO ID: 5079816

[Less] The occurrence of perfluorinated compounds (PFCs) in vegetables and fruits, as well as agricultural . . . [More] The occurrence of perfluorinated compounds (PFCs) in vegetables and fruits, as well as agricultural environment, was investigated in the downstream regions of Changshu fluorine-chemical industrial park (CFCIP) in China. Twenty-one PFCs were analyzed in irrigation water, agricultural soil, typical vegetables, and fruits, with the maximum total PFC concentrations of 369.9 ng/L, 64.7 ng/g dw, 11.5 ng/g ww, and 10.5 ng/g ww, respectively. Short-chained perfluoroalkyl carboxylic acids (PFCAs) such as perfluorooctanoic acid (PFOA), perfluorobutanoic acid (PFBA), and perfluorohexanoic acid were the dominant PFCs in terms of their concentrations and detection frequency. PFCs in irrigation water and agricultural soils showed a decreasing trend with increasing distance from CFCIP, while this pattern was not observed in agricultural products. The predominant compounds varied in different vegetables and fruits. Simultaneous bioaccumulation of PFBA and PFOA was found in melons and solanaceous species and pears. Leafy vegetables and grapes exhibited high bioaccumulation of PFOA and PFBA, respectively. Health risk assessment by calculating estimated daily intake showed that no direct risk was caused by the consumption of vegetables and fruits for the residents in the investigated regions. However, the tolerable weekly intake of PFOA exceeded the established thresholds for the adult residents. A comprehensive health assessment of the dietary exposure of PFCs, including all exposure pathways, in fluorine-chemical industrial park-impacted regions is needed.

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

Effects of fluorescent dissolved organic matters (FDOMs) on perfluoroalkyl acids (PFAAs) in lake and river water

Authors: Liu, WX; He, W; Wu, JY; Wu, WJ; Xu, FL (2019) Science of the Total Environment 666:598-607. HERO ID: 5080217

[Less] This study presents the effects of fluorescent dissolved organic matters (FDOM) on perfluoroalkyl acids . . . [More] This study presents the effects of fluorescent dissolved organic matters (FDOM) on perfluoroalkyl acids (PFAAs) in western Lake Chaohu and its inflow rivers. The surface water samples from the 27 sites in western Lake Chaohu and its inflow rivers were collected in March and September 2013. The contents of PFAAs and the FDOM in the water samples were measured by a high-performance liquid chromatograph - mass spectrometer (HPLC-MS) and by a fluorescence spectrophotometer, respectively. The temporal-spatial distributions of PFAAs and FDOM, as well as their interrelationships, were investigated. Eleven PFAA components were detected, and the mean concentration of total PFAAs (TPFAAs) in western Lake Chaohu and its inflow rivers were 12.93 ± 5.19 ng/L and 11.84 ± 9.50 ng/L, respectively. PFOA was the predominant contaminant in two regions (7.13 ± 3.07 ng/L and 4.30 ± 2.14 ng/L) followed by PFHxA (1.72 ± 0.80 ng/L and 1.42 ± 1.41 ng/L) and PFBA (1.44 ± 0.78 ng/L and 1.37 ± 0.78 ng/L). The mean concentration of total FDOM in western Lake Chaohu and its inflow rivers were 220.0 ± 40.30 μg quinine sulfate units (Q.S.)/L and 406.3 ± 213.1 μg Q.S./L, respectively. The significant, positive correlations were observed between the PFAAs and FDOMs in both the lake area and the inflow rivers. However, no significant correlation was observed between PFAAs and the dissolved organic carbon (DOC) in the lake area. This finding indicated that the residues and distributions of PFAAs were significantly dependent on the compositions of dissolved organic matters (DOM) and not on the total content of DOM.

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

Response to "Overgeneralization by Anderson et al. and Luz et al. regarding safety of fluorotelomer-base chemistry"

Authors: Anderson, JK; Luz, AL; Goodrum, P (2019) Regulatory Toxicology and Pharmacology. [Letter] HERO ID: 5097905


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

Perfluorohexanoic acid toxicity, part II: Application of human health toxicity value for risk characterization

Authors: Anderson, JK; Luz, AL; Goodrum, P; Durda, J (2019) Regulatory Toxicology and Pharmacology 103:10-20. HERO ID: 5097906

[Less] Perfluorohexanoic acid (PFHxA) is a short-chain, six-carbon PFAA and is a primary impurity, degradant, . . . [More] Perfluorohexanoic acid (PFHxA) is a short-chain, six-carbon PFAA and is a primary impurity, degradant, and metabolite associated with the short-chain fluorotelomer-based chemistry used in the United States, Europe and Japan today. With the shift towards short-chain PFAA chemistry, uncertainties remain regarding human health risks associated with current exposure levels. Here, we present a critical review and assessment of data relevant to human health risk assessment to today's short-chain PFAA chemistry. Human biomonitoring surveys indicate that PFHxA is infrequently detected in the environment as well as in human serum and urine; however, human health concerns may persist in locations where PFHxA is detected. In a companion paper (Luz et al., 2019) we comprehensively evaluate the available toxicity data for PFHxA, and derive a chronic human health-based reference dose (RfD) for PFHxA of 0.25 mg/kg-day based on benchmark dose modeling of renal papillary necrosis in chronically exposed female rats. In this paper, we apply this RfD in human health-based screening levels calculations, and derive a drinking water lifetime health advisory of 1400 μg/L and a residential groundwater screening level for children of 4000 μg/L. Compared to environmental concentration data, even sites with more elevated concentrations of PFHxA in the environment are at least an order of magnitude lower than these screening levels. Available PFHxA human serum and urine biomonitoring data, used as a biomarker for general population exposure, demonstrates that the general human population exposures to PFHxA are low. Previous estimates of daily intake rates for infants exposed to PFHxA through breast milk, formula, and baby foods (Lorenzo et al., 2016) combined with the most conservative PFHxA peer-reviewed toxicity value (Luz et al., 2019) demonstrate that the margin of safety for PFHxA is high. Therefore, PFHxA and related fluorotelomer precursors currently appear to present negligible human health risk to the general population and are not likely to drive or substantially contribute to risk at sites contaminated with PFAS mixtures. PFHxA may also represent a suitable marker for the safety of fluorotelomer replacement chemistry used today.

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

Addendum to Iwai and Hoberman (2014)-Reassessment of Developmental Toxicity of PFHxA in Mice

Authors: Iwai, H; Hoberman, AM; Goodrum, PE; Mendelsohn, E; Anderson, JK (2019) International Journal of Toxicology 1091581819837904. HERO ID: 5097907

[Less] This article presents a supplemental data analysis and evaluation of the findings from an oral (gavage) . . . [More] This article presents a supplemental data analysis and evaluation of the findings from an oral (gavage) combined developmental and perinatal/postnatal reproduction toxicity study of the ammonium salt of perfluorohexanoic acid (CASRN: 21615-47-4) in Crl: CD-1(ICR) mice. The original study has been cited as supporting a lowest-observed-adverse-effects level of 175 mg/kg/d and no-observed-adverse-effects level of 35 mg/kg/d for developmental effects from perfluorohexanoic acid (PFHxA, CASRN: 307-24-4) in mice. The statistical analysis reported in 2014 was accurate in terms of quantifying statistical significance within phase 2 of the study. However, given the low incidence of findings, the purpose of this article is to extend the analysis and interpretation of findings by pooling the control group information from both phases of the same study, comparing the study findings to the incidence rates for stillbirths and postpartum viability for this species and strain of mouse observed for similar studies conducted by the same laboratory, and evaluating data on the incidence and range of spontaneous eye abnormalities reported in the literature. Based on this supplemental evaluation, the original study supports a NOAEL of 175 mg/kg/d for PFHxA in mice, which is a factor of 5-fold higher than previously reported. Furthermore, to the extent that this study may be considered in the selection of a point of departure for PFHxA in mice, it is noted that 175 mg/kg/d for maternal exposure is an unbounded NOAEL for developmental effects, meaning that the study did not establish a dose at which developmental effects may occur.

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

Selection of High Flux Membrane for the Effective Removal of Short-Chain Perfluorocarboxylic Acids

Authors: Soriano, A; Gorri, D; Urtiaga, Ane (2019) HERO ID: 5079967