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Affinities of six anions (mesylate, acetate, trifluoroacetate, p‐toluenecarboxylate, p‐toluenesulfonate, and perfluorooctanoate) for three related Pt2+‐linked porphyrin nanocages were measured to probe the influence of different noncovalent recognition motifs (e. g. hydrogen bonding, electrostatics, π bonding) on anion binding. Two new hosts of M6L312+ (1b) and M4L28+ (2) composition (M=(en)Pt2+, L=(3‐py)4porphyrin) were prepared in a one‐pot synthesis and allowed comparison of hosts that differ in structure while maintaining similar N−H hydrogen‐bond donor ability. Comparisons of isostructural hosts that differ in hydrogen‐bonding ability were made between 1b and a related M6L312+ nanoprism (1a, M=(tmeda)Pt2+) that lacks N−H groups. Considerable variation in association constants (K1=1.6×103 M−1 to 1.3×108 M−1) and binding mode (exo vs. endo) were found for different host–guest combinations. Strongest binding was seen between p‐toluenecarboxylate and 1b, but surprisingly, association of this guest with 1a was only slightly weaker despite the absence of NH⋅⋅⋅O interactions. The high affinity between p‐toluenecarboxylate and 1a could be turned off by protonation, and this behavior was used to toggle between the binding of this guest and the environmental pollutant perfluorooctanoate, which otherwise has a lower affinity for the host. [ABSTRACT FROM AUTHOR]

Background: Exposures to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), environmentally persistent chemicals detectable in the blood of most Americans, have been associated with several health outcomes. To offer insight into their possible biologic effects, we evaluated the metabolomic correlates of circulating PFOS and PFOA among 3,647 participants in eight nested case-control serum metabolomic profiling studies from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Methods: Metabolomic profiling was conducted by Metabolon Inc., using ultra high-performance liquid chromatography/tandem accurate mass spectrometry. We conducted study-specific multivariable linear regression analyses estimating the associations of metabolite levels with levels of PFOS or PFOA. For metabolites measured in at least 3 of 8 nested case-control studies, random effects meta-analysis was used to summarize study-specific results (1,038 metabolites in PFOS analyses and 1,100 in PFOA analyses). Results: The meta-analysis identified 51 and 38 metabolites associated with PFOS and PFOA, respectively, at a Bonferroni-corrected significance level (4.8x10-5 and 4.6x10-5, respectively). For both PFOS and PFOA, the most common types of associated metabolites were lipids (sphingolipids, fatty acid metabolites) and xenobiotics (xanthine metabolites, chemicals). Positive associations were commonly observed with lipid metabolites sphingomyelin (d18:1/18:0) (P = 2.0x10-10 and 2.0x10-8, respectively), 3-carboxy-4-methyl-5-pentyl-2-furanpropionate (P = 2.7x10-15, 1.1x10-17), and lignoceroylcarnitine (C24) (P = 2.6x10-8, 6.2x10-6). The strongest positive associations were observed for chemicals 3,5-dichloro-2,6-dihydroxybenzoic acid (P = 3.0x10-112 and 6.8x10-13, respectively) and 3-bromo-5-chloro-2,6-dihydroxybenzoic acid (P = 1.6x10-14, 2.3x10-6). Other metabolites positively associated with PFOS included D-glucose (carbohydrate), carotene diol (vitamin A metabolism), and L-alpha-aminobutyric acid (glutathione metabolism), while uric acid (purine metabolite) was positively associated with PFOA. PFOS associations were consistent even after adjusting for PFOA as a covariate, while PFOA associations were greatly attenuated with PFOS adjustment. Conclusions: In this large metabolomic study, we observed robust positive associations with PFOS for several molecules. Further investigation of these metabolites may offer insight into PFOS-related biologic effects.

Many epidemiology studies have investigated associations of perfluorooctanoate (PFOA) exposures with a variety of adverse health outcomes for participants in the C8 Health Project. The exposure concentrations (i.e., air and groundwater) used in these studies were determined primarily based on participant's residential locations. However, for residential addresses that could not be geocoded to the street level, the exposure concentrations were assigned based on population-weighted ZIP code centroid, which may result in exposure mischaracterization. The aim of this current study is to evaluate the potential impact of mischaracterized exposure concentrations due to geocoding uncertainty on the predicted serum PFOA concentrations and the epidemiological association between PFOA exposure and preeclampsia. For both workplace addresses and incompletely geocoded residential addresses, we used Monte Carlo (MC) simulation to assign alternate geographic locations within the reported ZIP code (instead of population-weighted ZIP code centroids) and the corresponding exposure concentrations. We found that mischaracterization of residential exposure due to population-weighted ZIP code centroid assignment had no significant impact on the serum PFOA concentration predictions and the epidemiological association of PFOA exposure with preeclampsia. In contrast, the uncertainty in workplace exposure moderately impacted the rank exposure among the participants. We observed a 41% increase in the average adjusted odds ratio of preeclampsia occurrence that may be due to differing proportions of cases (64.3%) and controls (54.5%) with workplace address geocodes during pregnancy. This finding suggests that differential exposure mischaracterization can be reduced by obtaining accurate exposure information such as street addresses and tap water consumption, for both workplaces and residences. The analysis we present is one approach for estimating the potential impacts of positional errors in a geocoding-based exposure assessment on exposure estimates and epidemiological study results.

We recently utilized a suite of environmental fate and transport models and an integrated exposure and pharmacokinetic model to estimate individual perfluorooctanoate (PFOA) serum concentrations, and also assessed the association of those concentrations with preeclampsia for participants in the C8 Health Project (a cross-sectional study of over 69,000 people who were environmentally exposed to PFOA near a major U.S. fluoropolymer production facility located in West Virginia). However, the exposure estimates from this integrated model relied on default values for key independent exposure parameters including water ingestion rates, the serum PFOA half-life, and the volume of distribution for PFOA. The aim of the present study is to assess the impact of inter-individual variability and epistemic uncertainty in these parameters on the exposure estimates and subsequently, the epidemiological association between PFOA exposure and preeclampsia. We used Monte Carlo simulation to propagate inter-individual variability/epistemic uncertainty in the exposure assessment and reanalyzed the epidemiological association. Inter-individual variability in these parameters mildly impacted the serum PFOA concentration predictions (the lowest mean rank correlation between the estimated serum concentrations in our study and the original predicted serum concentrations was 0.95) and there was a negligible impact on the epidemiological association with preeclampsia (no change in the mean adjusted odds ratio (AOR) and the contribution of exposure uncertainty to the total uncertainty including sampling variability was 7%). However, when epistemic uncertainty was added along with the inter-individual variability, serum PFOA concentration predictions and their association with preeclampsia were moderately impacted (the mean AOR of preeclampsia occurrence was reduced from 1.12 to 1.09, and the contribution of exposure uncertainty to the total uncertainty was increased up to 33%). In conclusion, our study shows that the change of the rank exposure among the study participants due to variability and epistemic uncertainty in the independent exposure parameters was large enough to cause a 25% bias towards the null. This suggests that the true AOR of the association between PFOA and preeclampsia in this population might be higher than the originally reported AOR and has more uncertainty than indicated by the originally reported confidence interval.

Oily wastewater treatment is a global challenge due to the substantial amount of effluent resulted from many industrial and domestic activities. To overcome the challenge of using existing treatment approach and fouling, superoleophobic coatings were fabricated. In this study, a superoleophobic membrane surface was obtained using the sol-gel technique with perfluorooctanoate (PFO), poly (diallyl dimethylammonium chloride) (PDADMAC), and nanoparticles as complex-polymer nanocomposites. The effects of coating cycles on the surface structure, chemical properties, surface chemistry, and oleophobicity of the surface were examined using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and oil contact angle measurement. The results showed that the coated layer successfully adhered to the substrate surface. However, the chemical stability with respect to oil contact angle (OCA) revealed a decline at pH 7 and pH 9 and maintained stability at pH 3. Besides, oil flux at 63.0 L/m2. h was achieved for PDADMAC-Al 2 O 3 /44 wt% PFO and the highest separation efficiency of 98% was obtained. Furthermore, the oil rejection decreases as the oil concentration increases from 1 to 3 g/L. OCA of 155° was obtained after 5 coating cycles. Apart from mitigating substrate fouling, the superoleophobic and superhydrophilic coating can be applied to a ceramic-based hollow fibre membrane and efficiently used for the separation of oil from oily wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Perfluorooctanoate (PFOA) is widely used as a surfactant and has metabolic, immunologic, developmental, and genetic toxicity on marine organisms. However, the effects of PFOA on individual defense functions in mussels in the presence of titanium dioxide nanoparticles (nano-TiO 2) are poorly understood. To investigate the defense strategies and regulatory mechanisms of mussels under combined stressors, the thick-shell mussels Mytilus coruscus were exposed to different PFOA concentrations (0, 2 and 200 μg/L) and nano-TiO 2 (0 and 0.1 mg /L, size: 25 nm) for 14 days. The results showed that, compared to the control group, PFOA and nano-TiO 2 significantly reduced the number of byssal threads (NBT), byssal threads length (BTL), diameter of proximal threads (DPB), diameter of middle threads (DMB), diameter of distal byssal threads (DDB), adhesive plaque area (BPA), and breaking force of byssal threads (N). Under the influence of PFOA and nano-TiO 2 , the morphological surface smoothness of the fractured byssal threads surface increased, concurrently inducing an increased surface roughness in the adhesive plaques. Additionally, under the presence of PFOA and nano-TiO 2 , the foot displayed dispersed tissue organization and damaged villi, accompanied by an increased incidence of cellular apoptosis and an upregulation of the apoptosis gene caspase-8. Expression of the adhesion gene mfp-3 and byssal threads strength genes (preCOL-D, preCOL-NG) was upregulated. An interactive effect on the performance of byssal threads is observed under the combined influence of PFOA and nano-TiO 2. Under co-exposure to PFOA and nano-TiO 2 , the performance of the byssal threads deteriorates, the foot structure is impaired, and the genes mRNA expression of byssal thread secretory proteins have compensated for the adhesion and byssal threads strength by up-regulation. Within marine ecosystems, organic and particulate contaminants exert a pronounced effect on the essential life processes of individual organisms, thereby jeopardizing their ecological niche within community assemblages and perturbing the dynamic equilibrium of the overarching ecosystem. Perfluorooctanoic acid (PFOA) is prone to accumulate in marine organisms. TiO 2 nanoparticles (nano-TiO 2) are emerging environmental pollutants frequently found in marine environment. The effects of PFOA and nano-TiO 2 on marine mussels are not well understood, and their toxic mechanisms remain largely unknown. We investigated the impacts of PFOA and nano-TiO 2 on mussel byssus defense mechanisms. By assessing byssus performance indicators, morphological structures of the byssus, subcellular localization, and changes in byssal secretion-related genes, we revealed the combined effects and mechanisms through which these two types of pollutants may affect the functional capabilities and survival of mussels in the complex marine ecosystem. [Display omitted] • PFOA and nano-TiO 2 induce apoptosis in foot cells of mussels. • The expressions of some mussel foot proteins were up-regulated under PFOA and nano-TiO 2. • PFOA and nano-TiO 2 have negative impacts on the performance of mussel byssal threads. • PFOA and nano-TiO 2 cause damage to the structure of the foot. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are persistent anthropogenic chemicals that are widely distributed in the environment and pose significant risks to human health. Foam fractionation has emerged as a promising method to recover PFOS/PFOA from water. However, PFOS/PFOA concentrations in wastewater are often inadequate to generate stable foams due to their high critical micelle concentrations and the addition of a cosurfactant is necessary. In this study, we developed whey soy protein (WSP) as a green frother and collector derived from soybean meal (SBM), which is an abundant and cost-effective agro-industrial residue. WSP exhibited excellent foaming properties across a wide pH range and demonstrated strong collection capabilities that enhanced the recovery of PFOS/PFOA. The mechanism underlying this collection ability was elucidated through various methods, revealing the involvement of electrostatic attraction, hydrophobic interaction, and hydrogen bonding. Furthermore, we designed a double plate internal to improve the enrichment of PFOS/PFOA by approximately 2.3 times while reducing water recovery. Under suitable conditions (WSP concentration: 300 mg/L, pH: 6.0, air flowrate: 300 mL/min), we achieved high recovery percentages of 94–98% and enrichment ratios of 7.5–12.8 for PFOS/PFOA concentrations ranging from 5 to 20 mg/L. This foam fractionation process holds great promise for the treatment of PFOS/PFOA and other per- and polyfluoroalkyl substances. [Display omitted] • Whey soy protein (WSP) is developed as a frother and collector. • WSP significantly improves PFOS/PFOA foaming ability and stability. • Interaction mechanism between WSP and PFSO/PFOA is confirmed. • Double plate internal (DPI) have the ability to enhance the foam drainage. • PFOS/PFOA are effectively recovered by foam fractionation with WSP. [ABSTRACT FROM AUTHOR]

Background: The presence of perfluoroalkyl acids (PFAAs) in breast milk has been documented, but their lactational transfer has been rarely studied. Determination of the elimination rates of, these chemicals during breastfeeding is important and critical for assessing exposure in mothers, and infants., O b jectives: We aimed to investigate the association between breastfeeding and maternal serum, concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic, acid (PFNA), and perfluorohexane sulfonate (PFHxS). For a subset of the population, for, whom we also have their infants' measurements, we investigated associations of breastfeeding with, infant serum PFAA concentrations., Methods: The present analysis included 633 women from the C8 Science Panel Study who had, a child < 3.5 years of age and who provided blood samples and reported detailed information on, breastfeeding at the time of survey. PFAA serum concentrations were available for all mothers and, 8% (n=49) of the infants. Maternal and infant serum concentrations were regressed on duration of, breastfeeding. R esults: Each month of breastfeeding was associated with lower maternal serum concentrations, of PFOA (-3%, 95% CI:-5, -2%), PFOS (-3%, 95% CI:-3, -2%), PFNA (-2%, 95% CI, -2, -1%), and PFHxS (-1%, 95% CI:-2, 0%). The infant PFOA and PFOS serum concentrations, were 6% (95% CI: 1, 10%) and 4% (95% CI: 1, 7%) higher per month of breastfeeding., C onclusions: Breast milk is the optimal food for infants, but is also a PFAA excretion route for, lactating mothers and exposure route for nursing infants.

Among many short-term, subchronic, and chronic toxicology studies with ammonium perfluorooctanoate (PFOA), the gastrointestinal tract has not been identified as a target organ for PFOA-related toxicity in laboratory animals where the corresponding serum PFOA concentrations typically approach several orders of magnitude higher than the general human population. These lack of gastrointestinal tract-related findings were in direct contrast to an epidemiological observation where a positive trend was observed for ulcerative colitis, an idiopathic chronic inflammatory condition of the gut, in a Mid-Ohio River community whose drinking water contained higher levels of PFOA. This study was conducted to perform a histological reevaluation of large intestine sections in laboratory animals from 2 long-term toxicological studies: one was with Sprague Dawley rats that received ammonium PFOA in their diet for 2 years and the other one was with cynomolgus macaques that received daily capsules of ammonium PFOA for 6 months. In both studies, there was a lack of histological evidence of treatment-related inflammatory lesions that was suggestive of the occurrence of ulcerative colitis in these laboratory animals even under the most rigorous treatment schedules. These findings do not offer support for the biological plausibility of the epidemiological associations reported. [ABSTRACT FROM AUTHOR]

BACKGROUND: Drinking water in multiple water districts in the Mid-Ohio Valley has been contaminated with perfluorooctanoic acid (PFOA), which was released by a nearby DuPont chemical plant. Two highly contaminated water districts began granular activated carbon filtration in 2007. OBJECTIVES: To determine the rate of decline in serum PFOA, and its corresponding half-life, during the first year after filtration. METHODS: Up to six blood samples were collected from each of 200 participants from May 2007 until August 2008. The primary Source of drinking water varied over time for some participants; Our analyses were grouped according to water source at baseline in May-June 2007. RESULTS: For Lubeck Public Service District customers, the average decrease in serum PFOA concentrations between May-June 2007 and May-August 2008 was 32 ng/mL (26%) for those primarily consuming public water at home (n = 130), and 16 ng/mL (28%) for those primarily consuming bottled water at home (n = 17). For Little Hocking Water Association customers, the average decrease in serum PFOA concentrations between November-December 2007 and May-June 2008 was 39 ng/mL (11%) for consumers of public water (n = 39) and 28 ng/mL (20%) for consumers of bottled water (n = 11). The covariate-adjusted average rate of decrease in serum PFOA concentration after water filtration was 26% per year (95% confidence interval, 25-28% per year). CONCLUSIONS: The observed data are consistent with first-order elimination and a median serum PFOA half-life of 2.3 years. Ongoing follow-up will lead to improved half-life estimation.

Although many studies have evaluated the fate of per‐ and polyfluoroalkyl acids (PFAAs) in aquatic environments, few have observed their fate in terrestrial environments. It has been proposed that ingestion could be a major PFAA exposure route for humans. We determined PFAA uptake in radish, carrot, and alfalfa under a maximum bioavailability scenario. Bioconcentration factors (BCFs) were determined in the edible tissue of radish (perfluorobutanesulfonate [PFBS] = 72; perfluorohexanesulfonate [PFHxS] = 13; perfluoroheptanoate [PFHpA] = 65; perfluorooctanoate [PFOA] = 18; perfluorooctanesulfonate [PFOS] = 2.9; and perfluorononanoate [PFNA] = 9.6), carrot (PFBS = 5.9; PFHxS = 1.1; PFHpA = 29; PFOA = 3.1; PFOS = 1; and PFNA = 1.4), and alfalfa (PFBS = 107; PFHxS = 12; PFHpA = 91; PFOA = 10; PFOS = 1.4; and PFNA = 1.7). Some of these PFAA BCFs are as much as 2 orders of magnitude higher than those measured previously in plants grown in biosolid‐amended soils. Environ Toxicol Chem 2019;38:2497–2502. © 2019 SETAC [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Gamma and electron beam irradiation effective under reductive conditions. • Strong effect of dose-rate observed in electron beam (EB) irradiation. • Support of radiolytic decomposition by formate or nitrate in treated PFOA solutions. • EB irradiation decomposes PFOA in seconds at initial ppm level. • A successful kinetic modeling can be carried out based on known rate constants. Abstract It has been demonstrated through the use of both gamma-rays and beam of accelerated electrons (EB) for the radiolytic decomposition of PFOA in diluted aqueous solutions that the most reactive species among the products of water radiolysis are hydrated electrons e aq. The reaction of PFOA with the hydrated electrons takes place with the largest yield in strongly alkaline deaerated solutions. The PFOA decomposition performed at an initial concentration level of 1 mg/L by γ-irradiation requires the use of absorbed doses below 10 kGy, which, depending on the activity of employed 60Co source, requires 2–3 h irradiation time. Similar results were obtained at pH 12 in the presence and also in the absence of t -butanol in the treated solutions. In the case of EB irradiation in a wide range of the absorbed doses (up to 100 kGy), a very pronounced effect of the dose-rate was observed, which can be attributed to various recombination reactions of the products of water radiolysis. A significant improvement in the yield of the PFOA decomposition by EB irradiation can be observed in the presence of trace amounts of nitrate or 100 mM of a formate in the treated solutions. In optimized conditions, about 70–80% decomposition of the initial level of 1 ppm of PFOA can be obtained with an irradiation using 100 kGy absorbed dose, which corresponds to about 5 s treatment with the use of an employed electron accelerator. The acute toxicity measurements and a kinetic modeling are presented, together with a suggestion of the mechanism of radiolytic decomposition of PFOA. [ABSTRACT FROM AUTHOR]

Exposures to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), environmentally persistent chemicals detectable in the blood of most Americans, have been associated with several health outcomes. To offer insight into their possible biologic effects, we evaluated the metabolomic correlates of circulating PFOS and PFOA among 3,647 participants in eight nested case-control serum metabolomic profiling studies from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Metabolomic profiling was conducted by Metabolon Inc., using ultra high-performance liquid chromatography/tandem accurate mass spectrometry. We conducted study-specific multivariable linear regression analyses estimating the associations of metabolite levels with levels of PFOS or PFOA. For metabolites measured in at least 3 of 8 nested case-control studies, random effects meta -analysis was used to summarize study-specific results (1,038 metabolites in PFOS analyses and 1,100 in PFOA analyses). The meta -analysis identified 51 and 38 metabolites associated with PFOS and PFOA, respectively, at a Bonferroni-corrected significance level (4.8x10-5 and 4.6x10-5, respectively). For both PFOS and PFOA, the most common types of associated metabolites were lipids (sphingolipids, fatty acid metabolites) and xenobiotics (xanthine metabolites, chemicals). Positive associations were commonly observed with lipid metabolites sphingomyelin (d18:1/18:0) (P = 2.0x10-10 and 2.0x10-8, respectively), 3-carboxy-4-methyl-5-pentyl-2-furanpropionate (P = 2.7x10-15, 1.1x10-17), and lignoceroylcarnitine (C24) (P = 2.6x10-8, 6.2x10-6). The strongest positive associations were observed for chemicals 3,5-dichloro-2,6-dihydroxybenzoic acid (P = 3.0x10-112 and 6.8x10-13, respectively) and 3-bromo-5-chloro-2,6-dihydroxybenzoic acid (P = 1.6x10-14, 2.3x10-6). Other metabolites positively associated with PFOS included D-glucose (carbohydrate), carotene diol (vitamin A metabolism), and L-alpha-aminobutyric acid (glutathione metabolism), while uric acid (purine metabolite) was positively associated with PFOA. PFOS associations were consistent even after adjusting for PFOA as a covariate, while PFOA associations were greatly attenuated with PFOS adjustment. In this large metabolomic study, we observed robust positive associations with PFOS for several molecules. Further investigation of these metabolites may offer insight into PFOS-related biologic effects. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals that were widely used in manufacturing and are now present in the environment throughout the world. It is known that various PFAS are quantifiable in human in blood, but potential adverse health outcomes remain unclear. Sentinel and non-traditional model species are useful to study potential toxicity of PFAS in order to understand the relationship between environmental and human health. Here, we present a critical review of studies on the neurotoxicity of PFAS in sentinel and non-traditional laboratory model systems, including Caenorhabditis elegans (nematode), Dugesia japonica (planarian), Rana pipiens (frogs), Danio rerio and Oryzias melastigma (fish), and Ursus maritimus (polar bears). PFAS have been implicated in developmental neurotoxicity in non-traditional and traditional model systems as well as sentinel species, including effects on neurotransmitter levels, especially acetylcholine and its metabolism. However, further research on the mechanisms of toxicity needs to be conducted to determine if these chemicals are affecting organisms in a similar manner. Overall, findings tend to be similar among the various species, but bioaccumulation may vary, which needs to be taken into account in future studies by quantifying target organ concentrations of PFAS to better compare different species. Furthermore, data on the majority of PFAS is lacking in neurotoxicity testing, and additional studies are needed to corroborate findings thus far.

Highlights • PFOS and PFOA levels are suggestive of levels of industrialization and poor environmental awareness. • Concentrations of PFOS and PFOA in porewater were greater than those in surface water. • Results of this study provided additional understanding of PFOS and PFOA partitioning between sediment and porewater. • Field – based fate and partitioning of PFOS and PFOA were highly dependent on salinity gradients. • Adsorption of PFOS and PFOA can be greater than expected due salinity changes in aquatic environment. Abstract Global concern on emerging pollutants such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are well documented. Unfortunately, information is either scarce or non-existing on the presence of these chemicals in most developing nations like Nigeria. The current study examined the distribution pattern and trend of PFOS and PFOA in surface water, porewater (PW) and sediments collected from three geopolitical zones with different levels of industrialization in Nigeria. PFOS and PFOA were concentrated using solid-phase extraction, identified and quantified by high performance liquid chromatography interfaced to a triple quadruple mass spectrometer. Detection of both PFOS and PFOA in all samples suggested wide distribution across Nigeria. Generally, PFOS dominated aqueous concentrations ranging from 3.9 to 10.1 ng L−1 in surface water, 10.9 to 20.4 ng L−1 in PW and 5.1 to 10.4 ng g−1 in bottom sediment. Field-based partition coefficients (K d) for both PFOS and PFOA were significantly correlated with salinity (r 2 = 0.84 and 0.78 respectively, p < 0.01); The K d values increased exponentially as a function of salinity. The enrichment of both PFOS and PFOA on sediment increased with increasing organic matter while in water with increasing salinity. The detection of these chemicals across all samples suggested urgent attention in their risk assessment. [ABSTRACT FROM AUTHOR]

Exposure to perfluoroalkyl substances (PFAS) is associated with a range of adverse health effects. However, it remains unclear whether PFAS at environmentally relevant exposure levels are related to diabetes and metabolite concentrations in adults. Using cross-sectional data from 7904 adults (age ≥ 20 years) in the 2003–2012 National Health and Nutrition Examination Survey (NHANES), we examined the association of PFAS with the prevalence of diabetes and metabolite concentrations. A multivariate logistic regression was applied to investigate the associations of diabetes prevalence with serum perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorononanoate (PFNA) levels. A multivariate generalised linear regression was further performed to investigate the associations between PFAS exposure and some metabolites. We identified a strong positive association between serum PFOA and diabetes prevalence in men with an adjusted model (OR: 2.66, 95% CI: 1.63–4.35; P for trend = 0.001). No significant association between serum PFOA and diabetes prevalence was observed in women (OR: 1.47, 95% CI: 0.88–2.46; P for trend = 0.737). Furthermore, diabetes was not related to PFOS, PFHxS and PFNA, regardless of gender. In the gender-stratified generalised linear models, men and women with the highest PFOA levels demonstrated a 1.43% (95% CI: 0.62%–2.34%) and a 1.07% (95% CI: 0.27%–1.97%) greater increase in serum total cholesterol ( P for trend = 0.006 and 0.001) compared to those with the lowest PFOA levels. There were no significant associations between serum PFOA and other metabolites. These results provide epidemiological evidence that environment-related levels of serum PFOA may be positively associated with the prevalence of diabetes in men and with total cholesterol in adults. Further clinical and animal studies are urgently needed to elucidate putative causal relationships and shed light on the potential mode of action involved. [ABSTRACT FROM AUTHOR]

Perfluorooctanoate (PFOA) is a fully fluorinated eight-carbon fatty acid analog with exceptional stability toward degradation that has been used as an industrial surfactant and has been detected in environmental and biological matrices. Exposures to PFOA in the workplace and in the environment have continuously stimulated investigations into its potential human health hazards. In this article, the results of fifteen unpublished genotoxicity assays conducted with perfluorooctanoate (as either the linear or linear/branched ammonium salt (APFO) or the linear/branched sodium salt) are reported and include: seven mutation assays (three in vitro reverse mutation assays with histidine auxotrophic strains of Salmonella typhimurium, two in vitro reverse mutation assays with the tryptophan auxotrophic Escherichia coli WP2uvr strain, one in vitro mitotic recombination (gene conversion) assay with Saccharomyces cerevisiae D4, and an in vitro Chinese hamster ovary (CHO) HGPRT forward mutation assay); seven studies to assess potential for chromosomal damage (three in vitro CHO chromosomal aberration studies, an in vitro human whole blood lymphocyte chromosomal aberration study, and three in vivo mouse micronucleus assays); and an in vitro C3H 10T1/2 cell transformation assay. Although PFOA has not been demonstrated to be metabolized, all in vitro assays were conducted both in the presence and in the absence of a mammalian hepatic microsomal activation system. These assays were originally described in twelve contract laboratory reports which have been available via the United States Environmental Protection Agency public docket (Administrative Record 226) for over a decade; however, the details of these assays have not been published previously in the open scientific literature. With the exception of limited positive findings at high and cytotoxic concentrations in some assay trials which reflected the likely consequence of cytotoxic disruption of normal cellular processes and not a specific genotoxic effect, the results of the studies presented in this paper and other published results clearly demonstrate the absence of direct mutagenic or genotoxic risk associated with PFOA. This finding is consistent with the physical/chemical characteristics of PFOA and is supported by other published genotoxicity studies.

Two chronic dietary studies, conducted years apart, with ammonium perfluorooctanoate (APFO) in Sprague Dawley rats have been previously reported. Although both included male 300 ppm dietary dose groups, only the later study, conducted in 1990–1992 by Biegel et al., reported an increase in proliferative lesions (hyperplasia and adenoma) of the acinar pancreas. An assessment of the significance of the differences between both studies requires careful consideration of: the diagnostic criteria for proliferative acinar cell lesions of the rat pancreas (for example, the diagnosis of pancreatic acinar cell hyperplasia versus adenoma is based on the two-dimensional size of the lesion rather than distinct morphological differences); the basis for those criteria in light of their relevance to biological behavior; and the potential diagnostic variability between individual pathologists for difficult-to-classify lesions. A pathology peer review of male exocrine pancreatic tissues from the earlier study, conducted in 1981–1983 by Butenhoff et al., was undertaken. This review identified an increase in acinar cell hyperplasia but not adenoma or carcinoma in the earlier study. Both studies observed a proliferative response in the acinar pancreas which was more pronounced in the study by Biegel et al. Definitive reasons for the greater incidence of proliferative lesions in the later study were not identified, but some possible explanations are presented herein. The relevance of this finding to human risk assessment, in the face of differences in the biological behavior of human and rat pancreatic proliferative lesions and the proposed mechanism of formation of these lesions, are questionable.

Understanding sorption of PFOA on soil particles is crucial to evaluate its environmental risk. Here, sorption of PFOA onto ten agricultural soils was examined. The influence of soil physico-chemical properties on PFOA sorption was investigated. The sorption rate of PFOA followed a pseudo-second-order kinetics. Isotherm data of PFOA sorption was fitted with both Freundlich and linear models and the latter fitted better. The sorption-desorption of PFOA onto ten soil samples depended on soil organic carbon content and composition of soil minerals. The sorption and desorption isotherms of PFOA on ten soils were linear, except for the sorption of PFOA onto a few soils, which was described by the Freundlich equation with the parameter N >1. The main sorption mechanism of PFOA was hydrophobic interaction between the perfluorinated carbon chain and the organic matter of soil, as evidenced by the correlation between the solid-liquid distribution coefficient and the fraction of soil organic carbon. The sorption of PFOA in soils was highly irreversible. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Perfluorooctanoate (PFOA) has been associated with impaired lactation in mice. We examined whether maternal perfluorooctanesulfonate (PFOS) and PFOA concentrations correlated with duration of breastfeeding among women. METHODS: We randomly selected 1400 pregnant women from the Danish national birth cohort (1996–2002) and measured PFOS and PFOA concentrations in early pregnancy by using high performance liquid chromatography/tandem mass spectrometry. Self-reported data on the duration of any and exclusive breastfeeding were collected twice during telephone interviews around 6 and 18 months after the birth of the child. RESULTS: The duration of breastfeeding decreased with increasing concentrations of pregnancy PFOS and PFOA among multiparous women, for whom the adjusted odds ratios (OR) for weaning before 6 months of age were 1.20 (95% CI 1.06–1.37) per 10 ng/ml increase in PFOS concentrations and 1.23 (95% CI 1.13–1.33) per 1 ng/ml increase in PFOA concentrations. No consistent association was found for primiparous women. CONCLUSIONS: These findings suggest that PFOA and PFOS may reduce the ability to lactate, but could equally reflect reverse causation since no association was seen in primiparous women.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are found widespread in the environment and humans. The relation of PFASs to fertility has now been examined in a relatively large number of epidemiologic studies and a synthesis is in order. The aim of this study was to assess the current human epidemiologic evidence on the association between exposure to PFASs and measures of human fertility, with particular emphasis on perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). Systematic literature searches were initially conducted in MEDLINE and EMBASE and subsequently in references and citations of included papers. Studies were included if they assessed exposure to PFASs in biological samples in relation to reproductive hormones, semen characteristics, or time to pregnancy (TTP). Study characteristics and results were abstracted to predefined forms, and the studies were assessed for the risk of bias and confounding. Sixteen studies investigated the association between PFAS exposure in men and semen parameters, reproductive hormone levels, or TTP. There was a lack of consistent results among the numerous investigated exposure-outcome combinations. However, subtle associations between higher PFOS and lower testosterone or abnormal semen morphology cannot be excluded. Eleven studies assessed the association between PFAS exposure in women and TTP or reproductive hormones levels. Four of eight studies found prolonged TTP with higher PFOS or PFOA, but only one study found an association when restricting to nulliparous women. In men, there is little evidence of an association between PFAS exposure and semen quality or levels of reproductive hormones. For PFOS and PFOA, the literature indicates an association with female fecundability in parous women, which is most likely not causal. [ABSTRACT FROM PUBLISHER]

The sorption of perfluorooctanoate (PFOA) onto cyanobacterial biomass is critical to understand its subsequent transport and fate in aqueous environments, but the sorption mechanisms remain largely unknown. This study aimed to investigate the influences of pH, heavy metals, and phosphate on the sorption of PFOA onto cyanobacterial biomass. Results showed that an increase in pH led to a decrease in PFOA sorption, which may be due to electrostatic repulsion. PFOA sorption first decreased, then gradually increased and surpassed the blank in the presence of Pb2+. However, PFOA sorption was suppressed in the presence of Cu2+, Cd2+, and [ABSTRACT FROM AUTHOR]

Objectives: Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) have been widely used as industrial products, and are persistent organic pollutants due to their chemical stability. Previous studies suggested that PFOS and PFOA might disrupt thyroid hormone (TH) status. Although TH plays an important role in fetal growth during pregnancy, little attention has been paid to the relationships between maternal exposure to perfluorocarbons and TH statuses of mothers and fetuses. We investigated the effects of low levels of environmental PFOS and PFOA on thyroid function of mothers and infants. Methods: Of the eligible subjects in a prospective cohort, 392 mother-infant pairs were selected. Concentration of maternal serum PFOS and PFOA was measured in samples taken during the second and third trimesters or within 1 week of delivery. Blood samples for measuring thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels were obtained from mothers at early gestational stage (median 11.1 weeks), and from infants between 4 and 7 days of age, respectively. Results: Median concentrations of PFOS and PFOA were 5.2 [95 % confidence interval (CI) 1.6-12.3] and 1.2 (95 % CI limitation of detection-3.4) ng/mL, respectively. Maternal PFOS levels were inversely correlated with maternal serum TSH and positively associated with infant serum TSH, whereas maternal PFOA showed no significant relationship with TSH or FT4 among mothers and infants. Conclusions: These findings suggest that PFOS may independently affect the secretion and balances of maternal and infant TSH even at low levels of environmental exposure. [ABSTRACT FROM AUTHOR]

The consumption of lactic acid bacteria capable of binding or degrading food-borne carcinogens may reduce human exposure to these deleterious compounds. In this study, 25 Lactobacillus strains isolated from human, plant, or dairy environments were investigated for their potential probiotic capacity against perfluorooctanoate (PFOA) toxicity. The PFOA binding, tolerance ability, and acid and bile salt tolerance were investigated and assessed by principal component analysis. Additionally, the effect of different pH levels and binding times was assessed. These strains exhibited different degrees of PFOA binding; the strain with the highest PFOA binding capability was Lactobacillus plantarum CCFM738, which bound to 49.40 ± 1.5 % of available PFOA. This strain also exhibited relatively good cellular antioxidative properties, acid and bile salt tolerance, and adhesion to Caco-2 cells. This study suggests that L. plantarum CCFM738 could be used as a potential probiotic in food applications against PFOA toxicity. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are persistent organic pollutants in the environment and their occurrence causes toxicological effects on humans. We examined different conventional coagulant treatments such as alum, ferric chloride and polyaluminium chloride in removing these compounds. These were then compared with a natural coagulant (Moringa oleifera). We also investigated the powdered-activated carbon (PAC) and granular-activated carbon (GAC) for removing these compounds. At an initial dose of 5 mg/L, polyaluminium chloride led to a higher reduction of PFOS/PFOA compared with alum which in turn was higher than ferric. The removal efficiency increased with the increase in coagulant dose and decrease in pH.M. oleiferawas very effective in reducing PFOS and PFOA than conventional coagulants, with a reduction efficiencies of 65% and 72%, respectively, at a dose of 30 mg/L. Both PAC and GAC were very effective in reducing these compounds than coagulations. PAC led to a higher reduction in PFOS and PFOA than GAC due to its greater surface area and shorter internal diffusion distances. The addition of PAC (10 min contact time) with coagulation (at 5 mg/L dosage) significantly increased the removal efficiency, and the maximum removal efficiency was forM. oleiferawith 98% and 94% for PFOS and PFOA, respectively. The reduction efficiency of PFOS/PFOA was reduced with the increase in dissolved organic concentration due to the adsorption competition between organic molecules and PFOS/PFOA. [ABSTRACT FROM PUBLISHER]

Background Previous studies on the exposure to perfluoroalkyl acids (PFAAs) and female fertility have provided conflicting results. We aimed to investigate the association between several PFAAs and time to pregnancy among nulliparous women. Methods From 2008 to 2013, we included 1372 women from the Aarhus Birth Cohort, Aarhus University Hospital, Denmark, who provided data on time to pregnancy and a blood sample before 20 gestational weeks. We measured the levels of 16 PFAAs in maternal serum and report data for seven compounds with quantifiable values in at least 50% of samples. Fecundability ratios according to PFAA levels (quartiles or continuous levels) were estimated by discrete-time survival analyses, adjusted for potential confounders. We further investigated the association between PFAAs and infertility (time to pregnancy>12 months or infertility treatment prior to the studied pregnancy) by multivariable logistic regression. Results Median levels of perfluorooctane sulfonate and perfluorooctanoate were 8.3 and 2.0 ng/mL. Overall, no obvious associations were found between any PFAAs and fecundability or infertility. Adjusted fecundability ratios (95% confidence intervals) were 1.09 (0.92–1.29) for perfluorooctane sulfonate and 1.10 (0.93–1.30) for perfluorooctanoate (highest versus lowest quartile). Conclusions We found no evidence of an association between present serum levels of PFAAs and longer time to pregnancy or infertility in nulliparous women. This study further adds to the sparse knowledge on PFAAs besides perfluorooctane sulfonate and perfluorooctanoate. [ABSTRACT FROM AUTHOR]

The distribution and fate of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) were investigated in the water and sediment of Bohai Bay, China, during 2011–2013. A total of 360 water samples and 60 sediment samples were collected from 20 locations. The median concentrations of PFOS and PFOA were 4.8 and 12.15 ng/L in the water, and 2.65 and 0.62 ng/g-dry in the sediment, respectively. Significant enrichment were observed for PFOS and PFOA in water of sea surface microlayer. The concentrations of these two compounds showed an apparent gradient from nearshore to offshore stations. The correlation analysis and the distribution tendencies indicated that freshwater inflowing to the bay was the main source of PFOS and PFOA. The salinity of seawater and the total organic carbon (TOC) content of sediment heavily affected the spatial distribution and the partitioning of PFOS and PFOA in the sediment-water system. [ABSTRACT FROM AUTHOR]

While selected perfluoroalkyl acids/substances (PFAAs) like perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) have been detected and measured in laboratory, a method to estimate the total concentration of PFAAs (∑PFAA) in serum has not been developed. Because of the health concerns associated with PFAAs and because of the inability of every laboratory to measure every PFAA as well as because of the non-availability of sensitive enough equipment to be able to detect very small amounts of certain PFAAs, it is of interest to know ∑PFAA. We used data from the National Health and Nutrition Examination Survey for the years 2005–2012 to develop regression models to estimate ∑PFAA by using the levels of PFOA and PFOS only. While data for 2005–2008 were used to develop regression models, data for 2009–2012 were used to evaluate the accuracy of the developed models. Over 63% of observed values for evaluation data were found to be within 10% of the predicted values. The model so developed can be used with just the knowledge of the age, gender, and concentrations of PFOA and PFOS. While the data used to develop the model were generated in U.S., the model can be used to estimate ∑PFAA for data collected in North America and Europe and probably elsewhere in the world. [ABSTRACT FROM AUTHOR]

Background: We previously demonstrated an association between plasma perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) and longer time to pregnancy (TTP) in a sample from the Danish National Birth Cohort (DNBC, 1996-2002). In this study we investigated this association in a new sample from the same cohort. Methods: Sample 1 consisted of 440 women, and Sample 2 consisted of 1161 women from whom we previously published the associations between PFOS or PFOA and TTP. We performed sample-specific and pooled analyses using discrete-time survival analyses to estimate fecundability ratios according to PFOS and PFOA quartiles, adjusted for potential confounders chosen guided by a directed acyclic graph. We also estimated odds ratios for infertility (TTP > 12 months or infertility treatment) according to PFOS and PFOA by multivariable logistic regression. Results: In Sample 1 PFOS was not associated with lower fecundability ratios or infertility, and there was a tendency towards longer TTP with increasing PFOA only in parous women. In Sample 2 previously reported associations were again seen. In the pooled analyses including both parous and nulliparous women fecundability ratios were 13-22 % lower for the three higher quartiles of PFOS or PFOA compared to the reference quartile. Conclusions: The pooled analyses were driven by the larger old sample, but we did not corroborate our previous finding of an association between high PFOS and longer TTP in the new sample. The tendency towards an association for PFOA and TTP in parous women may be due to reverse causation. Results from the new sample are more in line with the recent literature. [ABSTRACT FROM AUTHOR]

Perfluorooctanoate (PFOA) is a persistent chemical that has been detected globally in the natural aquatic environment, while the waste discharge of fluoropolymer industry is one of the major sources of PFOA pollution. In this study, the removal and recovery of PFOA by nanofiltration (NF) were investigated with ammonium perfluorooctanoate model solutions under a wide range of PFOA concentrations. Performances of two commercially available NF membranes, namely NF270, NF90, were evaluated. The results show that the NF90 membrane offered a higher PFOA rejection (almost 100% at a PFOA concentration below 800 mg L −1 ). Using NF90 membrane, a model solution with a higher initial PFOA concentration of 1000 mg L −1 was used to further test the membrane performance. Both stable osmotic pressure at membrane surface and high PFOA rejection (99.3%) were obtained when the PFOA concentration was larger than a certain value due to the formation of micelles. Furthermore, membrane operation parameters (i.e. stirring speed, pH, temperature, and permeate flux) on the TMP and the PFOA concentration in permeate were investigated under a much higher initial PFOA concentration (10,000 mg L −1 ). The experimental results clearly confirm that recovery of highly concentrated PFOA of more than 117073.7 mg L −1 could be achieved by one-step NF treatment, while the permeate could be further treated by multi-stage NF to fully recover the PFOA. It was also found that the permeability of membrane could be recovered completely by simple water rinse, suggesting that NF is highly applicable for recovery of PFOA from wastewater in fluoropolymer production. [ABSTRACT FROM AUTHOR]

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), are a family of commonly used industrial chemicals whose persistence and ubiquity in blood samples of humans and wildlife have become a growing concern. Despite PFOS and PFOA having been found in human blood and tissue samples from occupationally exposed workers and the general worldwide population, little systematic knowledge has accrued with respect to exposure levels in Uyghurs in the Sinkiang-Uighur Autonomous Region of China, which is predominantly agricultural and pastoral. Our goal was to provide background data for biological monitoring in the general population of this region. In this study, 110 self-reported healthy human serum samples were collected from nonoccupationally exposed Uyghurs volunteers and analyzed by microbore HPLC-electrospray tandem mass spectrometry. Among the 110 blood specimens, PFOS was detected in 102 samples (93 %) and ranged from the lower limit of quantification of 0.01 to 22.63 μg/L with a median of 1.93 μg/L (interquartile range 1.00-3.43 μg/L). The median was higher among males (2.39 μg/L; interquartile range 1.23-4.40 μg/L) than that among females (1.20 μg/L; interquartile range 0.83-2.77 μg/L). No significant difference was observed with respect to age. The concentration of PFOA was lower than that of PFOS and was found only in seven samples (6 %) at concentrations above the limit of quantification. This study is the first investigation to reveal serum PFOS and PFOA levels in the general population of Uyghurs. PFOS and PFOA concentrations found in the present investigation were lower than those found in recent studies consisting of subjects from different geographic locations (PFOS 5.0-44.7 μg/L, PFOA 1.5-10 μg/L). [ABSTRACT FROM AUTHOR]

Background: Exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) is ubiquitous in most regions of the world. The most commonly studied PFASs are perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). Animal studies indicate that maternal PFAS exposure is associated with reduced fetal growth. However, the results of human studies are inconsistent. Objectives: To summarize the evidence of an association between exposure to PFASs, particularly PFOS and PFOA, and human fetal growth. Methods: Systematic literature searches were performed in MEDLINE and EMBASE. We included original studies on pregnant women with measurements of PFOA or PFOS in maternal blood during pregnancy or the umbilical cord and associations with birth weight or related outcomes according to the PFAS level. Citations and references from the included articles were investigated to locate more relevant articles. Study characteristics and results were extracted to structured tables. The completeness of reporting as well as the risk of bias and confounding were assessed. Results: Fourteen studies were eligible. In utero PFOA exposure was associated with decreased measures of continuous birth weight in all studies, even though the magnitude of the association differed and many results were statistically insignificant. PFOS exposure and birth weight were associated in some studies, while others found no association. Conclusions: Higher PFOS and PFOA concentrations were associated with decreased average birth weight in most studies, but only some results were statistically significant. The impact on public health is unclear, but the global exposure to PFASs warrants further investigation. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and accumulate in humans. PFAS are suspected to affect the neuropsychological function of children, but only few studies have evaluated the association with childhood attention and executive function. To investigate the association between intrauterine exposure to PFAS and offspring attention and executive function. A total of 1593 children from the Danish National Birth Cohort, born 1996–2003, were included. The levels of 16 PFAS were measured in maternal plasma during pregnancy. At 5 years of age, the Test of Everyday Attention for Children at Five (TEACh-5) and the Behavior Rating Inventory of Executive Function (BRIEF) were performed. TEACh-5 scores were standardized to a mean of 0 and standard deviation (SD) of 1. BRIEF scores were standardized to a mean of 50 and a SD of 10. The associations between levels of seven PFAS and TEACh-5 and BRIEF were examined by multivariable linear regression adjusted for potential confounders. Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention [standardized mean difference (95% confidence interval) −0.5 (−0.7, −0.3), highest versus lowest quartile]. Other PFAS were not clearly associated with selective attention, and we found no clear associations between PFAS exposure and sustained attention. For parent rated executive function, perfluorooctanoate (PFOA) was associated with poorer scores, standardized mean difference 3.8 (95% confidence interval 1.6, 6.0), highest versus lowest quartile. Regarding other PFAS, the associations were less clear. We found no clear associations between any PFAS and executive function rated by preschool teachers. Intrauterine exposure to PFOSA was associated with poorer selective attention, while PFOA was associated with poorer executive function. Given the widespread nature of PFAS exposure, these findings may have public health implications, warranting further investigation. • Plasma samples were obtained during pregnancy in 1593 Danish women. • Perfluoroalkyl and polyfluoroalkyl substances (PFAS) were measured in the plasma. • Attention and executive function was evaluated in the offspring at age 5. • Perfluorooctane sulfonamide (PFOSA) was associated with poorer selective attention. • Perfluorooctanoate (PFOA) was associated with poorer executive function. [ABSTRACT FROM AUTHOR]

Previous studies suggested that perfluorooctanoate (PFOA) could activate the estrogen receptor (ER). The present study examined the hypothesis that PFOA can activate ER using an in vivo uterotrophic assay in CD-1 mice and an in vitro reporter assay. Pre-pubertal female CD-1 mice fed an estrogen-free diet from postnatal day (PND)14 through weaning on PND18 were administered 0, 0.005, 0.01, 0.02, 0.05, 0.1, or 1 mg/kg PFOA or 17β-estradiol (E 2 , 0.5 mg/kg) from PND18–20. In contrast to E 2 , PFOA caused no changes in the relative uterine weight, the expression of ER target genes, or the morphology of the uterus/cervix and/or vagina on PND21. Treatment of a stable human cell line containing an ER-dependent luciferase reporter construct with a broad concentration range of PFOA caused no change in ER-dependent luciferase activity; whereas E 2 caused a marked increase of ER-dependent luciferase activity. These data indicate that PFOA does not activate mouse or human ER. [ABSTRACT FROM AUTHOR]

Rainbow trout ( Oncorhynchus mykiss ) confined to respirometer-metabolism chambers were dosed with perfluorooctanoate (PFOA) by intra-arterial (i.a.) injection and sampled to obtain concentration time-course data for plasma, urine, and expired water. The data were then analyzed by compartmental modeling to estimate rates of renal and branchial clearance. Averaged across all animals, the renal clearance rate (1.35 mL/h/kg) was more than ten times greater than the branchial clearance rate (0.12 mL/h/kg). The average whole-body elimination half-life was 12.6 d, which is somewhat longer than values obtained in previous studies with smaller trout. The tissue distribution of PFOA was assessed by collecting tissues at the end of chambered exposures and in a separate tissue time-course experiment. From the time-course study it appeared that an internal steady-state was established within 24 h of i.a. injection. Consistent with previous studies, the rank order of PFOA concentration in tissues at steady state was: plasma > liver > kidney > muscle. In a second set of chambered experiments, fish were exposed to PFOA in water to determine the rate of branchial uptake. Branchial uptake rates were too low to assess directly by measuring PFOA concentrations in inspired and expired water. Uptake rate constants (mean 0.19 L/d/kg; 0.1% uptake efficiency) were therefore estimated by compartmental modeling using plasma concentration time-course data and model parameters derived from the elimination experiments. It is clear from this effort that elimination of PFOA by trout occurs primarily via the renal route. This finding is consistent with numerous studies of mammals and suggests that trout possess membrane transporters that facilitate the movement of PFOA from plasma to urine. [ABSTRACT FROM AUTHOR]

Abstract: We examined whether perfluorooctanoate (PFOA) or perfluorooctane sulfonate (PFOS) had obesogenic effects and if they increased spontaneous intestinal tumorigenesis in the mouse model C57BL/6J-Min/+ (multiple intestinal neoplasia) after in utero exposure. The dams were exposed to PFOA or PFOS (0.01, 0.1 or 3.0mg/kg bw/day) by po gavage on GD1–17. The Min/+ and wild-type offspring were terminated at week 11 for examination of intestinal tumorigenesis or at week 20 for obesogenic effect, respectively. Body weights of the dams and pups were recorded throughout life. Food intake was determined at week 6 and 10. Blood glucose (non-fasted) was measured at week 6 and 11. No obesogenic effect of PFOA or PFOS was observed up to 20 weeks of age. PFOA or PFOS did not increase the incidence or number of tumors in the small intestine or colon of the Min/+ mice or affect their location along the intestines. Feed intake was not affected. There were some indications of toxicity of PFOA, but not of PFOS. There was lower survival of pups after 3.0mg/kg PFOA, lower body weight in pups after 3.0 and possibly 0.1mg/kg PFOA, and increased relative liver weight after 0.01 and possibly 0.1mg/kg PFOA. Plasma glucose was lower after 0.01 and 0.1mg/kg PFOA. In conclusion, exposure to PFOA and PFOS in utero with the doses used did not have obesogenic effect on either Min/+ or wild-type mice, at least not up to 11 or 20 weeks of age, nor increased intestinal tumorigenesis in Min/+ mice. [Copyright &y& Elsevier]

Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are ubiquitous synthetic chemicals with no known effect on human cancer development. This article systematically and critically reviews the epidemiologic evidence regarding the association between PFOA and PFOS exposure and cancer risk in humans. Eighteen epidemiologic studies - eight of PFOA, four of PFOS, and six of both PFOA and PFOS - have estimated associations of exposure to these chemicals with cancer incidence or mortality, with studies equally divided between occupational and nonoccupational settings. Although some statistically significant positive associations have been reported, for example, with cancers of the prostate, kidney, testis, and thyroid, the majority of relative risk estimates for both PFOA and PFOS have been between 0.5 and 2.0 (with 95% confidence intervals including 1.0), inconsistently detected across studies, counterbalanced by negative associations, not indicative of a monotonic exposure-response relationship, and not coherent with toxicological evidence in animals, in which the primary target organs are the liver, testis (Leydig cells), and pancreas (acinar cells). Many positive associations with PFOA exposure were detected in community settings without occupational exposure and were not supported by results in exposed workers. Given that occupational exposure to PFOA and PFOS is one to two orders of magnitude higher than environmental exposure, the discrepant positive findings are likely due to chance, confounding, and/or bias. Taken together, the epidemiologic evidence does not support the hypothesis of a causal association between PFOA or PFOS exposure and cancer in humans. [ABSTRACT FROM AUTHOR]

Editor’s Highlight: Vaccines and their possible adverse effects have received a great deal of popular attention, often based on sketchy science. In this issue of ToxSci, Luster and colleagues provide an example of how quality toxicological research can reveal connections between vaccines, immune function, and environmental exposures. The authors examined a human population that was exposed to perfluorooctanoate (PFOS) and how they responded to vaccines for influenza viruses. The results showed that individuals with high levels of PFOS had weaker antibody responses. Even though an increase in self-reported infections was not observed in this study, the fact that such inadvertent exposures can blunt one of the most important public health interventions demands further attention. Elderly and infirm populations often receive higher doses of vaccines to generate a more robust antibody response. The reported findings suggest that individuals exposed to certain environmental contaminants may also require higher doses of vaccines, or at least titer checks to confirm appropriate vaccine response. –Gary W. MillerSupported by several epidemiological studies and a large number of animal studies, certain polyfluorinated alkyl acids are believed to be immunotoxic, affecting particularly humoral immunity. Our aim was to investigate the relationship between the antibody response following vaccination with an inactivated trivalent influenza vaccine and circulating levels of perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS). The study population consisted of 411 adults living in the mid-Ohio region of Ohio and West Virginia where public drinking water had been inadvertently contaminated with PFOA. They participated in a larger cross-sectional study in 2005/2006 and were followed up in 2010, by which time serum levels of PFOA had been substantially reduced but were still well above those found in the general population. Hemagglutination inhibition tests were conducted on serum samples collected preinfluenza vaccination and 21±3 days postvaccination in 2010. Serum samples were also analyzed for PFOA and PFOS concentrations (median: 31.5 and 9.2ng/ml, respectively). Questionnaires were conducted regarding the occurrence and frequency of recent (during the last 12 months) respiratory infections. Our findings indicated that elevated PFOA serum concentrations are associated with reduced antibody titer rise, particularly to A/H3N2 influenza virus, and an increased risk of not attaining the antibody threshold considered to offer long-term protection. Although the direct relationship between weakened antibody response and clinical risk of influenza is not clear, we did not find evidence for an association between self-reported colds or influenza and PFOA levels nor between PFOS serum concentrations and any of the endpoints examined. [ABSTRACT FROM PUBLISHER]

This study examined the prevalence of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) in river water samples (n = 56) and suspended solids (n = 5) from three major Western Cape rivers, in South Africa. Solid phase extraction (SPE) followed by liquid chromatography combined with electrospray tandem mass spectrometry (LC-MS/MS) using an analytical method developed in ISO 25101 (2009), PFOS and PFOA concentration in river water and in suspended solids from the rivers was investigated and quantified. From the results, PFOA and PFOS were detected in all the river water samples and were found in concentrations up to 314 and 182 ng/L for Diep River; 390 and 47 ng/L for Salt River; and 146 and 23 ng/L for Eerste River, respectively. In suspended solids, concentrations for PFOS and PFOA were 28 and 26 ng/g for Diep River; 16 and less than limit of detection for Eerste River; and 14 and 5 ng/g for Salt River, respectively. Some of these concentrations are higher than those previously reported in similar studies in various countries, and this suggests there is a cause for concern, in the Western Cape, South Africa, particularly in catchments where river and ground water is drawn for agricultural purposes in the province. [ABSTRACT FROM AUTHOR]

Highlights: [•] Perfluorooctanoate in methanol solutions decreased with length of storage. [•] Methyl perfluorooctanoate and methyl formate increased with length of storage. [•] Methyl perfluorooctanoate increased with increase in methyl formate. [•] Methyl perfluorooctanoate increased when perfluorooctanoate decreased. [•] Variation in the solutions stored around 5°C was smaller than that at room temp. [ABSTRACT FROM AUTHOR]

In order to compare between in vivo toxicity studies, dosimetry is needed to translate study-specific dose regimens into dose metrics such as tissue concentration. These tissue concentrations may then be compared with in vitro bioactivity assays to perhaps identify mechanisms relevant to the lowest observed effect level (LOEL) dose group and the onset of the observed in vivo toxicity. Here, we examine the perfluorinated compounds (PFCs) perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS). We analyzed 9 in vivo toxicity studies for PFOA and 13 in vivo toxicity studies for PFOS. Both PFCs caused multiple effects in various test species, strains, and genders. We used a Bayesian pharmacokinetic (PK) modeling framework to incorporate data from 6 PFOA PK studies and 2 PFOS PK studies (conducted in 3 species) to predict dose metrics for the in vivo LOELs and no observed effect levels (NOELs). We estimated PK parameters for 11 combinations of chemical, species, strain, and gender. Despite divergent study designs and species-specific PK, for a given effect, we found that the predicted dose metrics corresponding to the LOELs (and NOELs where available) occur at similar concentrations. In vitro assay results for PFOA and PFOS from EPA’s ToxCast project were then examined. We found that most in vitro bioactivity occurs at concentrations lower than the predicted concentrations for the in vivo LOELs and higher than the predicted concentrations for the in vivo NOELs (where available), for a variety of nonimmunological effects. These results indicate that given sufficient PK data, the in vivo LOELs dose regimens, but not necessarily the effects, could have been predicted from in vitro studies for these 2 PFCs. [ABSTRACT FROM PUBLISHER]

Fetal exposure to the perfluoroalkyl acids, perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), has been associated with lower birth weight and lower weight and body mass index (weight (kg)/height (m)²) in early infancy. It is, however, unclear if exposure to prenatal PFOS and PFOA has a lasting influence on growth. We estimated the associations between the maternal plasma level of PFOS or PFOA and the children's body mass index, waist circumference, and risk of overweight at 7 years of age. A total of 1,400 women were randomly selected from the Danish National Birth Cohort among those who provided blood samples early in pregnancy and gave birth to liveborn singletons in 1996-2002. Weight and height information at 7 years was available for 811 children. Multiple linear and logistic regression models were used for analyses. Maternal PFOS and PFOA concentrations were overall inversely but nonsignificantly associated with the children's body mass index, waist circumference, and risk of overweight at 7 years of age. In conclusion, plasma levels of PFOS and PFOA in pregnant women did not seem to have any appreciable influence on their children's anthropometry at this point in childhood. [ABSTRACT FROM AUTHOR]

Abstract: Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are two emerging contaminants that have been detected in all environmental compartments. However, while most of the studies in the literature deal with their presence or removal in wastewater treatment, few of them are devoted to their detection in treated drinking water and fate during drinking water treatment. In this study, analyses of PFOS and PFOA have been carried out in river water samples and in the different stages of a drinking water treatment plant (DWTP) which has recently improved its conventional treatment process by adding ultrafiltration and reverse osmosis in a parallel treatment line. Conventional and advanced treatments have been studied in several pilot plants and in the DWTP, which offers the opportunity to compare both treatments operating simultaneously. From the results obtained, neither preoxidation, sand filtration, nor ozonation, removed both perfluorinated compounds. As advanced treatments, reverse osmosis has proved more effective than reverse electrodialysis to remove PFOA and PFOS in the different configurations of pilot plants assayed. Granular activated carbon with an average elimination efficiency of 64±11% and 45±19% for PFOS and PFOA, respectively and especially reverse osmosis, which was able to remove ≥99% of both compounds, were the sole effective treatment steps. Trace levels of PFOS (3.0–21ng/L) and PFOA (<4.2–5.5ng/L) detected in treated drinking water were significantly lowered in comparison to those measured in precedent years. These concentrations represent overall removal efficiencies of 89±22% for PFOA and 86±7% for PFOS. [Copyright &y& Elsevier]

Abstract: A novel SnO2-Sb/CA electrode, possessing high surface area, strong adsorption capacity, good electrical conductivity and electrocatalytic activity, was firstly proposed for ultrasonic electrochemical oxidation (US-EC) of persistent high concentration perfluorooctanoate (PFOA) in this study. The optimal calcination temperature for sinking micro-sized SnO2-Sb particles existed on the surface of CA into the structure of CA as nanoparticles was 600°C. Its application on degrading PFOA (60mL of 100mgL−1) exhibited efficient electrocatalytic performance. After 5h electrolysis, over 91% of PFOA was degraded with a first-order kinetic constant of 0.52h−1 and over 86% TOC removal was achieved, while 47% PFOA removal and 33% TOC removal were obtained in traditional electrochemical (EC) process. The main role of determining the decomposition efficiency, i.e., the mass transport, hydroxyl radical (·OH) generation and electrode surface reaction, were greatly enhanced in US-EC system. Additionally, the generated intermediates existing on electrode surface and in solution were separately detected after different electrolysis time and the proper mechanism for efficient removing PFOA in US-EC process was investigated in detail. At early reaction stage (<0.5h), the intermediate products on SnO2-Sb/CA surface were C5F11COO−, C4F9COO−, C3F7COO−, C2F5COO−, CF3COO−, while in solution were C5F11COO−, C4F9COO−, C3F7COO−. At late reaction stage (>5h), the intermediates either on electrode surface or in solution became the same including C5F11COO−, C4F9COO−, C3F7COO−. [Copyright &y& Elsevier]

Abstract: Exposure of mice to perfluorooctanoate (PFOA) evokes pronounced hepatomegaly along with significant alterations in both the histological structure and immune status of the liver. The present study was designed to evaluate the effects of this perfluorochemical on immune-mediated liver damage. In this connection, the influence of both sub-acute (10 days), moderate-dose (0.002% w/w=3±0.7mg/kg body weight/day) and short-term (28 days), low-dose (0.00005% w/w=70±2μg/kg body weight/day) dietary pretreatment with PFOA on the development of concanavalin A (Con A)-induced liver damage in mice was examined. With sub-acute, moderate, but not short-term, low-dose exposure, PFOA aggravated the acute liver damage caused by Con A, i.e., elevated serum levels of transaminases and led to more pronounced damage of hepatic tissue. This aggravation was associated with significantly enhanced hepatic level of interleukin-6 (IL-6), but unaltered hepatic levels of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin-4 (IL-4). Moreover, hepatic DNA fragmentation was not changed by sub-acute exposure to the moderate-dose. Our findings imply that exposure to PFOA may sensitize hepatic parenchymal cells to other toxicants that activate the hepatic immune system and thereby aggravate liver injury during acute inflammation. [Copyright &y& Elsevier]