Health & Environmental Research Online (HERO)


Per- and Polyfluoroalkyl Substances (PFAS)


398 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

Temporal trends of PFSAs, PFCAs and selected precursors in Australian serum from 2002 to 2013 : Supplementary materials

Authors: Eriksson, U; Mueller, JF; Toms, LL; Hobson, P; Kärrman, A (2017) Environmental Pollution 220. HERO ID: 3981676

Abstract: Supplemental materials

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

An investigation of the effects of geometry design on refrigerant flow mal-distribution in parallel flow condenser using a hybrid method of finite element approach and CFD simulation

Authors: Shojaeefard, MH; Nourbakhsh, SD; Zare, J (2017) HERO ID: 3859952

[Less] Flow mal-distribution in tubes is an important problem in parallel flow heat exchangers (PFHXs) which . . . [More] Flow mal-distribution in tubes is an important problem in parallel flow heat exchangers (PFHXs) which should be considered in heat exchanger modeling. In the present study, a hybrid method is developed for flow distribution forecasting based on simultaneous use of computational fluid dynamics (CFD) simulation for 3D analysis of flow in PFHX headers and finite element model for solving flow within tubes. The developed method forecasts are verified against the experimental data of a parallel flow condenser (PFC) performance. The method is then utilized to investigate the effects of tube protrusion depth, inlet tube location, inlet tube diameter and combination of tube protrusion depth and inlet tube location on refrigerant flow mal-distribution. The data indicate flow mal-distribution increment (increase of standard deviation (STD) from 0.51% to 1.77%) by increasing the tube protrusion depth from 1/4 to 3/4 of header diameter which results in about 14% increment in pressure drop and 3.9% decrement in capacity. Also, reduction of flow mal-distribution in cases of increasing the inlet tube diameter and locating the header inlet on the top of the header, a small distance away from the first tube is observed. The presented model and results can be used to accurately design PFCs. (C) 2016 Elsevier Ltd. All rights reserved.

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

Developing a hybrid procedure of one dimensional finite element method and CFD simulation for modeling refrigerant flow mal-distribution in parallel flow condenser

Authors: Shojaeefard, MH; Zare, J; Nourbakhsh, SD (2017) HERO ID: 3859953

[Less] Mal-distribution of refrigerant flow in flat tubes is an important problem in parallel flow heat exchangers . . . [More] Mal-distribution of refrigerant flow in flat tubes is an important problem in parallel flow heat exchangers (PFHXs) which should be considered in heat exchanger modeling. In the present study, a hybrid method is developed for flow distribution forecasting based on simultaneous use of computational fluid dynamics (CFD) simulation for 3D analysis of flow in PFHX headers and one dimensional finite element model for solving flow within flat tubes. The experimental data of a parallel flow condenser (PFC) performance is collected to verify the developed method. The average absolute deviations of 2.8%, 4.1% and 3% from experimental data for pressure drop, capacity and outlet temperature respectively, indicate the model validity. Slight increase of mass flow rate with moving toward the bottom tubes of the inlet header shows insignificant effect of gravity when vapor-phase flow is present. Also, comparing the pressure drop data of the developed method with those of uniform distribution model demonstrates reduction of average absolute deviation from 28.7% to 2.8%. The proposed model has the advantage of predicting PFC overall performance and can be used to accurately design and optimize headers and multiport flat tubes. (C) 2016 Elsevier Ltd and IIR. All rights reserved.

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

A Robust Method for Routine Analysis of Perfluorooctane Sulfonate (PFOS) and Perfluorohexane Sulfonate (PFHxS) in Various Edible Crop Matrices

Authors: Xiang, Lei; Sun, TFei; Chen, Lei; Xiao, Tao; Cai, QY; Li, Hui; He, DeC; Wong, MH; Li, YanWen; Mo, CeHui (2017) HERO ID: 3859955

[Less] A reliable, sensitive, and efficient method was developed for routine analysis of perfluorooctane sulfonate . . . [More] A reliable, sensitive, and efficient method was developed for routine analysis of perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) in various edible crop matrices including cereal (grain), root vegetable (carrot), leafy vegetable (lettuce), and melon vegetable (pumpkin). The target analytes were extracted by ion-pair approach followed by solid-phase extraction clean-up and HPLC-MS/MS. The type of extraction solvent, clean-up cartridge, and the usage of Supelclean graphitized carbon were evaluated to reach an optimized pretreatment procedure. The matrix-matched standard calibrations relative to the isotope-labeled internal standard were used in the developed method to obtain more reliable quantitative results. The average recoveries at four spiked levels (0.5, 10, 25, 50 ng/g) in the diverse matrices ranged from 70.9 to 114.6% with relative standard deviations (RSD) lower than 11.5%. The matrix-dependent method detection limits using the common equipment (HPLC-MS/MS) were between 0.020 and 0.140 ng/g (dw), equivalent to the 3-130 pg/g (fw), corresponding to the sensitivity of superior equipment (e.g., UPLC-MS/MS and HPLC-QTOF-HRMS). Furthermore, the developed method was conferred with the practicality through determination of the analytes in actual crops sampled from several farms in China's Pearl River Delta.

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

Early-life exposure to perfluoroalkyl substances and childhood metabolic function

Authors: Fleisch, AF; Rifas-Shiman, SL; Mora, AM; Calafat, AM; Ye, X; Luttmann-Gibson, H; Gillman, MW; Oken, E; Sagiv, SK (2017) Environmental Health Perspectives 125:481-487. HERO ID: 3858513

[Less] BACKGROUND: Perfluoroalkyl substances (PFASs) are synthetic chemicals that may persist . . . [More] BACKGROUND: Perfluoroalkyl substances (PFASs) are synthetic chemicals that may persist in the environment and in humans. There is a possible association between early-life PFAS exposure and metabolic dysfunction in later life, but data are limited.

METHODS: We studied 665 mother-child pairs in Project Viva, a Boston, Massachusetts-area cohort recruited 1999-2002. We quantified concentrations of PFASs [perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHxS), and perfluorodecanoate (PFDeA)] in maternal plasma collected at the first prenatal visit (median, 9.6 weeks gestation) and in child plasma from the mid-childhood research visit (median, 7.7 years). We assessed leptin, adiponectin, and homeostatic model assessment of insulin resistance (HOMA-IR) in mid-childhood. We fit covariate-adjusted linear regression models and conducted stratified analyses by child sex.

RESULTS: Children with higher PFAS concentrations had lower HOMA-IR [e.g., -10.1% (95% CI: -17.3, -2.3) per interquartile range increment in PFOA]. This inverse association between child PFAS and HOMA-IR was more pronounced in females [e.g., PFOA: -15.6% (95% CI: -25.4, -4.6) vs. -6.1% (95% CI: -16.2, 5.2) for males]. Child PFAS plasma concentrations were not associated with leptin or adiponectin. Prenatal PFAS plasma concentrations were not associated with leptin, adiponectin, or HOMA-IR in offspring.

CONCLUSIONS: We found no evidence for an adverse effect of early-life PFAS exposure on metabolic function in mid-childhood. In fact, children with higher PFAS concentrations had lower insulin resistance. Citation: Fleisch AF, Rifas-Shiman SL, Mora AM, Calafat AM, Ye X, Luttmann-Gibson H, Gillman MW, Oken E, Sagiv SK. 2017. Early-life exposure to perfluoroalkyl substances and childhood metabolic function. Environ Health Perspect 125:481-487; http://dx.doi.org/10.1289/EHP303.

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

Prenatal exposure to perfluoroalkyl substances and adiposity in early and mid-childhood

Authors: Mora, AM; Oken, E; Rifas-Shiman, SL; Webster, TF; Gillman, MW; Calafat, AM; Ye, X; Sagiv, SK (2017) Environmental Health Perspectives 125:467-473. HERO ID: 3859823

[Less] BACKGROUND: Few studies have examined whether prenatal exposure to perfluoroalkyl substances . . . [More] BACKGROUND: Few studies have examined whether prenatal exposure to perfluoroalkyl substances (PFASs) is associated with childhood adiposity.

OBJECTIVE: We examined associations of prenatal exposure to PFASs with adiposity in early and mid-childhood.

METHODS: We measured plasma PFAS concentrations in 1,645 pregnant women (median, 9.6 weeks gestation) enrolled in Project Viva, a prospective pre-birth cohort study in Massachusetts (USA), between 1999 and 2002. We assessed overall and central adiposity in 1,006 children in early childhood (median, 3.2 years) and 876 in mid-childhood (median, 7.7 years) using anthropometric and dual X-ray absorptiometry (DXA) measurements. We fitted multivariable linear regression models to estimate exposure-outcome associations and evaluated effect modification by child sex.

RESULTS: Median (25-75th percentiles) prenatal plasma perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and perfluorononanoate (PFNA) concentrations in children assessed in early childhood were 5.6 (4.1-7.7), 24.8 (18.4-33.9), 2.4 (1.6-3.8), and 0.6 (0.5-0.9) ng/mL, respectively. Among girls, each interquartile range increment of prenatal PFOA concentrations was associated with 0.21 kg/m(2) (95% CI: -0.05, 0.48) higher body mass index, 0.76 mm (95% CI: -0.17, 1.70) higher sum of subscapular and triceps skinfold thickness, and 0.17 kg/m(2) (95% CI: -0.02, 0.36) higher DXA total fat mass index in mid-childhood. Similar associations were observed for PFOS, PFHxS, and PFNA. We observed null associations for boys and early-childhood adiposity measures.

CONCLUSIONS: In this cohort, prenatal exposure to PFASs was associated with small increases in adiposity measurements in mid-childhood, but only among girls. Citation: Mora AM, Oken E, Rifas-Shiman SL, Webster TF, Gillman MW, Calafat AM, Ye X, Sagiv SK. 2017. Prenatal exposure to perfluoroalkyl substances and adiposity in early and mid-childhood. Environ Health Perspect 125:467-473; http://dx.doi.org/10.1289/EHP246.

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

A nationwide survey of perfluorinated alkyl substances in waters, sediment and biota collected from aquatic environment in Vietnam: Distributions and bioconcentration profiles

Authors: Lam, NH; Cho, CR; Kannan, K; Cho, HS (2017) Journal of Hazardous Materials 323:116-127. HERO ID: 3859829

[Less] Water, sediment, various tissues of fish, crustacean, gastropod and bivalve were collected from major . . . [More] Water, sediment, various tissues of fish, crustacean, gastropod and bivalve were collected from major river basins in Vietnam and analyzed for the presence of perfluorinated alkyl substances (PFASs). Furthermore, the occurrence of PFASs in coastal, tap and well waters collected from eight different regions in Vietnam was investigated. PFOA and PFOS were consistently detected as the dominant PFASs in surface waters. The greatest concentrations of PFOA (53.5ngL(-1)) and PFOS (40.2ngL(-1)) were found in a surface water sample collected from a channel that receives wastewater treatment plant discharges. PFOS and PFHxS were found as the predominant PFASs in sediments. The greatest PFAS concentration in biota was 16.9ng PFUnDA g(-1) wet weight found in a fish liver. Some long-chain PFCAs including PFNA, PFUnDA and PFTrDA as well as PFHxS were more abundant than short-chain PFASs in biota tissues. The measured concentrations of PFOS and PFOA in surface and tap waters were below the provisional health advisory. The rank order of mean bioconcentration factor of PFOS in biota was; crustacean (115L/kg), gastropod (1117L/kg), fish (1120L/kg) and bivalve (2110L/kg). This study provides baseline information for a better understanding of PFASs contamination in Vietnam.

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

Predictors of per- and polyfluoroalkyl substance (PFAS) plasma concentrations in 6-10 year old American children

Authors: Harris, MH; Rifas-Shiman, SL; Calafat, AM; Ye, X; Mora, AM; Webster, TF; Oken, E; Sagiv, SK (2017) Environmental Science and Technology 51:5193-5204. HERO ID: 3859811

[Less] Certain per- and polyfluoroalkyl substances (PFASs) are suspected developmental toxicants, but data . . . [More] Certain per- and polyfluoroalkyl substances (PFASs) are suspected developmental toxicants, but data on PFAS concentrations and exposure routes in children are limited. We measured plasma PFASs in children aged 6-10 years from the Boston-area Project Viva prebirth cohort, and used multivariable linear regression to estimate associations with sociodemographic, behavioral, and health-related factors, and maternal PFASs measured during pregnancy. PFAS concentrations in Project Viva children (sampled 2007-2010) were similar to concentrations among youth participants (aged 12-19 years) in the 2007-8 and 2009-10 National Health and Nutrition Examination Survey (NHANES); mean concentrations of most PFASs declined from 2007 to 2010 in Project Viva and NHANES. In mutually adjusted models, predictors of higher PFAS concentrations included older child age, lower adiposity, carpeting or a rug in the child's bedroom, higher maternal education, and higher neighborhood income. Concentrations of perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexanesulfonate (PFHxS), and 2-(N-methyl-perfluorooctane sulfonamido) acetate (Me-PFOSA-AcOH) were 26-36% lower in children of black mothers compared to children of white mothers and increased 12-21% per interquartile range increase in maternal pregnancy PFASs. Breastfeeding duration did not predict childhood PFAS concentrations in adjusted multivariable models. Together, the studied predictors explained the observed variability in PFAS concentrations to only a modest degree.

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 perfluoroalkyl substances in cord serum and association with growth indicators in newborns from Beijing

Authors: Shi, Y; Yang, L; Li, J; Lai, J; Wang, Y; Zhao, Y; Wu, Y (2017) Chemosphere 169:396-402. HERO ID: 3827535

[Less] Perfluoroalkyl substances (PFASs), a group of environmental pollutants, persistently exist in the environment. . . . [More] Perfluoroalkyl substances (PFASs), a group of environmental pollutants, persistently exist in the environment. To investigate the associations between PFASs levels in cord serum and birth weight, birth length and ponderal index, we measured PFASs in cord serum samples from 170 infants from Feb. 2012 to Jun. 2012 in Beijing, China. The mean concentrations in cord serum samples for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnA) were 1.285 ng/mL, 1.228 ng/mL, 0.230 ng/mL, 0.224 ng/mL, 0.100 ng/mL and 0.085 ng/mL, respectively. First-born children had slightly higher exposure levels of PFHxS (p < 0.001) and PFOA (p = 0.03) than second-born or third-born children. The spearman correlation coefficients with gestation time were individually 0.160 (p = 0.038) for PFHxS and 0.202 (p = 0.008) for PFOA. Both univariate and multivariate linear regression analysis showed that the exposure levels of PFASs had no statistically significant associations with birth weight, birth length or ponderal index in the present population. For male infants, we observed that PFHxS positively correlated with birth length, but the levels of PFUnA were negatively associated with birth length.

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 perfluoroalkyl substances on neurosteroid synthetic enzymes in the rat

Authors: Xu, R; Shen, Q; Li, S; Li, X; Li, H; Lü, Y; Lian, QQ; Ge, RS (2017) Chemico-Biological Interactions 272:182-187. HERO ID: 3856450

[Less] Perfluoroalkylated substances (PFASs), including perfluorooctyl sulphonate (PFOS) and perfluorooctane . . . [More] Perfluoroalkylated substances (PFASs), including perfluorooctyl sulphonate (PFOS) and perfluorooctane acid (PFOA), have been classified as persistent organic pollutants and are known to cause endocrine-disrupting effects in humans. The objective of the present study was to compare the potencies of four different PFASs, PFOS, PFOA, perfluorohexyl sulfonate (PFHxS), and perfluorobutyl sulfonate (PFBS), to inhibit neurosteroidogenic 5α-reductase 1 (SRD5A1), 3α-hydroxysteroid dehydrogenase (AKR1C9), and retinol dehydrogenase 2 (RoDH2) in rats. The potencies of PFASs to inhibit SRD5A1 are PFOS > PFOA > PFHxS = PFBS, with IC50 values of PFOS and PFOA of 1.92 ± 0.07 and 14.24 ± 0.07 μM and no effects for PFHxS and PFBS at 100 μM, respectively. The potencies of PFASs to inhibit AKR1C9 and RoDH2 are PFOS > PFOA > PFHxS = PFBS, with IC50 values of PFOS and PFOA on these two enzymes about 100 μM and no effects for PFHxS and PFBS at 100 μM, respectively. PFOS and PFOA competitively inhibited rat SRD5A1. In conclusion, PFOS and PFOA are potent inhibitors of rat SRD5A1, thereby controlling the biosynthesis of neurosteroids.