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Thyroid cancer incidence has been steadily increasing over the past decade in the United States (US). A discussion exists regarding the potential contribution of exposure to endocrine-disrupting chemicals, encompassing certain per- and poly-fluoroalkyl substances (PFASs). This ecological study evaluated the potential correlation between PFAS levels in drinking water and thyroid cancer incidence in the US. Data on age-adjusted thyroid cancer incidence rate (per 100,000 persons) by county were obtained from the Centers for Disease Control and Prevention (CDC) for US counties with available data in 2015-2019. Data on PFAS concentrations in the drinking water of selected community water systems (CWSs) were obtained from the CDC National Environmental Public Health Tracking Network in 2013-2015. The correlation between PFASs in CWSs and thyroid cancer incidence was calculated using Spearman correlation. A statistically significant correlation was found between perfluorooctanoic acid (PFOA) (r = 0.031; p = 0.043), perfluorononanoic acid (PFNA) (r = 0.058; p ≤ 0.001), and thyroid cancer incidence. The results suggest a potential link between certain PFAS exposures and thyroid cancer risk. However, due to the nature of an ecological study, no conclusions can be drawn at the individual level or causality. More research is needed, particularly on an individual level to allow for more detailed exposure assessment.

Background: Lifestyle and environmental pollution harm male fertility. Perfluoroalkyl substances (PFAS) are bio-accumulates in the environment as well as in several human tissues, and one of the most common PFAS is perfluorooctanoic acid (PFOA). Therefore, this study aimed to evaluate the in vitro effects of PFOA with hydrophobic and waterproofing properties on motility and bio-functional sperm parameters. Methods: To accomplish this, 50 healthy men with normozoospermia and not exposed to high doses of PFAS were enrolled. Their spermatozoa were incubated for 3 h with increasing concentrations of PFOA (0, 0.01, 0.1, and 1 mM) to evaluate its effects. In particular, we evaluated the effects of PFOA on total and progressive sperm motility and, by flow cytometry, on the following bio-functional sperm parameters: degree of chromatin compactness, viability, early and late apoptosis, mitochondrial membrane potential, the degree of lipoperoxidation, and concentrations of mitochondrial superoxide anion. Results: The results showed that PFOA decreased both total and progressive sperm motility, impaired chromatin compactness, and increased sperm lipid peroxidation and mitochondrial superoxide anion levels. Conclusions: This study showed that PFOA alters several sperm parameters and thus it may play a negative role in male fertility. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a persistent environmental contaminant that can accumulate in the human body due to its long half-life. This substance has been associated with liver, pancreatic, testicular and breast cancers, liver steatosis and endocrine disruption. PFOA is a member of a large group of substances also known as "forever chemicals" and the vast majority of substances of this group lack toxicological data that would enable their effective risk assessment in terms of human health hazards. This study aimed to derive a health-based guidance value for PFOA intake (ng/kg BW/day) from in vitro transcriptomics data. To this end, we developed an in silico workflow comprising five components: (i) sourcing in vitro hepatic transcriptomics concentration-response data; (ii) deriving molecular points of departure using BMDExpress3 and performing pathway analysis using gene set enrichment analysis (GSEA) to identify the most sensitive molecular pathways to PFOA exposure; (iii) estimating freely-dissolved PFOA concentrations in vitro using a mass balance model; (iv) estimating in vivo doses by reverse dosimetry using a PBK model for PFOA as part of a quantitative in vitro to in vivo extrapolation (QIVIVE) algorithm; and (v) calculating a tolerable daily intake (TDI) for PFOA. Fourteen percent of interrogated genes exhibited in vitro concentration-response relationships. GSEA pathway enrichment analysis revealed that "fatty acid metabolism" was the most sensitive pathway to PFOA exposure. In vitro free PFOA concentrations were calculated to be 2.9% of the nominal applied concentrations, and these free concentrations were input into the QIVIVE workflow. Exposure doses for a virtual population of 3,000 individuals were estimated, from which a TDI of 0.15 ng/kg BW/day for PFOA was calculated using the benchmark dose modelling software, PROAST. This TDI is comparable to previously published values of 1.16, 0.69, and 0.86 ng/kg BW/day by the European Food Safety Authority. In conclusion, this study demonstrates the combined utility of an "omics"-derived molecular point of departure and in silico QIVIVE workflow for setting health-based guidance values in anticipation of the acceptance of in vitro concentration-response molecular measurements in chemical risk assessment. [ABSTRACT FROM AUTHOR]

The UV treatment of 6:2 FTAB involves the mitigation of this persistent chemical by the impact of ultraviolet radiation, which is known for its resistance to environmental breakdown. UV treatment of PFOA and/or 6:2 FTAB, and the role of responsible species and their mechanism have been presented. Our investigation focused on the degradation of perfluorooctanoic acid (PFOA) and 6:2 fluorotelomer sulfonamide alkyl betaine (6:2 FTAB, Capstone B), using UV photolysis under various pH conditions. Initially, we used PFOA as a reference, finding a 90% decomposition after 360 min at the original (unadjusted) pH 5.6, with a decomposition rate constant of (1.08 ± 0.30) × 10−4 sec−1 and a half-life of 107 ± 2 min. At pH 4 and 7, degradation averaged 85% and 80%, respectively, while at pH 10, it reduced to 57%. For 6:2 FTAB at its natural pH 6.5, almost complete decomposition occurred. The primary UV transformation product was identified as 6:2 fluorotelomer sulfonic acid (6:2 FTSA), occasionally accompanied by shorter-chain perfluoroalkyl acids (PFAAs) including PFHpA, PFHxA, and PFPeA. Interestingly, the overall decomposition percentages were unaffected by pH for 6:2 FTAB, though pH influenced rate constants and half-lives. In PFOA degradation, direct photolysis and reaction with hydrated electrons were presumed mechanisms, excluding the involvement of hydroxyl radicals. The role of superoxide radicals remains uncertain. For 6:2 FTAB, both direct and indirect photolysis were observed, with potential involvement of hydroxyl, superoxide radicals, and/or other reactive oxygen species (ROS). Clarification is needed regarding the role of e a q − in the degradation of 6:2 FTAB. [ABSTRACT FROM AUTHOR]

The presence of per- and polyfluoroalkyl substances (PFASs) in aquatic environments is often persistent and widespread. Understanding the potential adverse effects from this group of chemicals on aquatic communities allows for better hazard characterization. This study examines impacts on zebrafish (Danio rerio) embryo physiology, behavior, and lipid levels from exposure to perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and heptadecafluorooctanesulfonic acid (PFOS). Embryos were exposed to lethal and sublethal levels of each chemical and monitored for alterations in physiological malformations, mortality, lipid levels, and behavior (only PFOA and PFHxS). The predicted 50% lethal concentrations for 120 hpf embryos were 528.6 ppm PFOA, 14.28 ppm PFHxS, and 2.14 ppm PFOS. Spine curvature and the inability of the 120 hpf embryos to maintain a dorsal-up orientation was significantly increased at 10.2 ppm PFHxS and 1.9 ppm PFOS exposure. All measured 120 hpf embryo behaviors were significantly altered starting at the lowest levels tested, 188 ppm PFOA and 6.4 ppm PFHxS. Lipid levels decreased at the highest PFAS levels tested (375 PFOA ppm, 14.4 PFHxS ppm, 2.42 ppm PFOS). In general, the PFAS chemicals, at the levels examined in this study, increased morphological deformities, embryo activity, and startle response time, as well as decreased lipid levels in 120 hpf zebrafish embryos. [ABSTRACT FROM AUTHOR]

Vertical transmission of metabolic constituents from mother to child contributes to the manifestation of disease phenotypes in early life. This study probes the vertical transmission of metabolites from mothers to offspring by utilizing machine learning techniques to differentiate between true mother–child dyads and randomly paired non-dyads. Employing random forests (RF), light gradient boosting machine (LGBM), and logistic regression (Elasticnet) models, we analyzed metabolite concentration discrepancies in mother–child pairs, with maternal plasma sampled at 24 weeks of gestation and children's plasma at 6 months. The propensity of vertical transfer was quantified, reflecting the likelihood of accurate mother–child matching. Our findings were substantiated against an external test set and further verified through statistical tests, while the models were explained using permutation importance and SHapley Additive exPlanations (SHAP). The best model was achieved using RF, while xenobiotics were shown to be highly relevant in transfer. The study reaffirms the transmission of certain metabolites, such as perfluorooctanoic acid (PFOA), but also reveals additional insights into the maternal influence on the child's metabolome. We also discuss the multifaceted nature of vertical transfer. These machine learning-driven insights complement conventional epidemiological findings and offer a novel perspective on using machine learning as a methodology for understanding metabolic interactions. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous and persistent environmental contaminants originating from many everyday products. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are two PFAS that are commonly found at high concentrations in aquatic environments. Both chemicals have previously been shown to be toxic to fish, as well as having complex and largely uncharacterized mixture effects. However, limited information is available on marine and estuarine species. In this study, embryonic and larval sheepshead minnows (Cyprinodon variegatus) were exposed to several PFAS mixtures to assess lethal and sublethal effects. PFOS alone was acutely toxic to larvae, with a 96 h LC50 of 1.97 mg/L (1.64–2.16). PFOS + PFOA resulted in a larval LC50 of 3.10 (2.62–3.79) mg/L, suggesting an antagonistic effect. These observations were supported by significant reductions in malondialdehyde (105% ± 3.25) and increases in reduced glutathione concentrations (43.8% ± 1.78) in PFOS + PFOA exposures compared to PFOS-only treatments, indicating reduced oxidative stress. While PFOA reduced PFOS-induced mortality (97.0% ± 3.03), perfluorohexanoic acid (PFHxA) and perfluorobutanoic acid (PFBA) did not. PFOS alone did not affect expression of peroxisome proliferator-activated receptor alpha (pparα) but significantly upregulated apolipoprotein A4 (apoa4) (112.4% ± 17.8), a downstream product of pparα, while none of the other individually tested PFAS affected apoa4 expression. These findings suggest that there are antagonistic interactions between PFOA and PFOS that may reduce mixture toxicity in larval sheepshead minnows through reduced oxidative stress. Elucidating mechanisms of toxicity and interactions between PFAS will aid environmental regulation and management of these ubiquitous pollutants. [ABSTRACT FROM AUTHOR]

Studies comparing the ocular toxicity potential between legacy and alternative PFAS are lacking. To address this research gap, zebrafish larvae were exposed to both legacy PFAS (i.e., perfluorooctanesulfonic acid [PFOS] and perfluorooctanoic acid [PFOA]) and their corresponding alternatives (i.e., perfluorobutanesulfonic acid [PFBS] and perfluorobutanoic acid [PFBA]). Alterations in their visual behaviors, such as phototactic and optomotor responses (OMR), were assessed at sublethal concentrations. Gene expression variations in visual function-associated pathways were also measured. Visual behavioral assessment revealed that PFOS exposure resulted in concentration-dependent reductions in phototactic responses at 10–1000 μg/L, with PFOA exerting reduction effects only at 100 mg/L. However, their two alternatives had no effect at all tested concentrations. Following an improved contrast-OMR (C-OMR) assessment, PFOS decreased the OMR to a water flow stimulus at 10, 100, and 1000 μg/L. The gene expression analysis revealed that PFOS exposure markedly downregulated most genes involved in the opsins in the photoreceptor and phototransduction cascade, which explains the observed visual behavior changes well. Our findings indicate that PFOS is the most likely PFAS to cause visual toxicity, with PFOA present but less likely, and their substitutes, PFBS and PFBA, cannot be classified as visually toxic to zebrafish. [ABSTRACT FROM AUTHOR]

Information regarding per- and polyfluorinated substances concentrations in biological samples from the Thai population was still lacking. A sensitive bioanalytical method was developed and validated for the quantification of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) levels in human plasma. Simple protein precipitation and LC–MS/MS techniques were used with stable isotope internal standards of 13C8–PFOS and 13C8–PFOA. The validated method followed the ICH bioanalytical validation guideline, and the results showed good accuracy, precision, and reproducibility. The validated analytical method was then applied to determine PFOS and PFOA concentrations in 50 human plasma samples from the National Blood Center, Thai Red Cross Society. The concentrations were found to be in ranges of <0.91–6.27 ng/mL for PFOS and <0.49–2.72 ng/mL for PFOA. PFOS was also measured separately for its isomers, and the geometric means of the linear isomer (L–PFOS) and branched isomer (br–PFOS) in plasma samples were at 1.85 and 0.41 ng/mL, respectively. Both PFOS and PFOA concentrations were lower in comparison to previous reports from other countries. The present study showed the application of our reliable method to determine PFOS and PFOA in biological samples in order to monitor the human exposure of both chemicals in Thailand. [ABSTRACT FROM AUTHOR]

The extensive use and bioaccumulation of Perfluoroalkyl Substances (PFAS) over time raise concerns about their impact on health, including mental issues such as depression. This study aims to evaluate the association between PFAS and depression. In addition, considering the importance of PFAS as an endocrine disruptor and in adipogenesis, the analyses will also be stratified by body fat status. A cross-sectional study with 479 subjects (56.4% women, 25–89 years) was conducted. Four PFAS were measured: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluorooctane sulfonate (PFOS). The Poisson regression model was applied using robust error variances. The fully adjusted model included age, sex, educational level, income, smoking, physical activity, body fat percentage, and the questionnaire to assess depression. The prevalence of depression and high body fat was 7.9% and 41.1%, respectively. Only PFOA was significantly associated with depression in the entire sample (prevalence rate (PR): 1.91; confidence interval (CI95%): 1.01–3.65). However, in the group with normal adiposity, PFOA (3.20, CI95%: 1.46–7.01), PFNA (2.54, CI95%: 1.29–5.00), and PFDA (2.09, CI95%: 1.09–4.00) were also significant. Future research should investigate the role of obesity as well as the biological plausibility and possible mechanisms increasing the limited number of evidences between PFAS and depression. [ABSTRACT FROM AUTHOR]

Thyroid cancer incidence has been steadily increasing over the past decade in the United States (US). A discussion exists regarding the potential contribution of exposure to endocrine-disrupting chemicals, encompassing certain per- and poly-fluoroalkyl substances (PFASs). This ecological study evaluated the potential correlation between PFAS levels in drinking water and thyroid cancer incidence in the US. Data on age-adjusted thyroid cancer incidence rate (per 100,000 persons) by county were obtained from the Centers for Disease Control and Prevention (CDC) for US counties with available data in 2015–2019. Data on PFAS concentrations in the drinking water of selected community water systems (CWSs) were obtained from the CDC National Environmental Public Health Tracking Network in 2013–2015. The correlation between PFASs in CWSs and thyroid cancer incidence was calculated using Spearman correlation. A statistically significant correlation was found between perfluorooctanoic acid (PFOA) (r = 0.031; p = 0.043), perfluorononanoic acid (PFNA) (r = 0.058; p ≤ 0.001), and thyroid cancer incidence. The results suggest a potential link between certain PFAS exposures and thyroid cancer risk. However, due to the nature of an ecological study, no conclusions can be drawn at the individual level or causality. More research is needed, particularly on an individual level to allow for more detailed exposure assessment. [ABSTRACT FROM AUTHOR]

Introduction: Neurological diseases can stem from environmental influences such as antecedent viral infections or exposure to potential toxicants, some of which can trigger immune responses leading to neurological symptoms. Theiler's murine encephalomyelitis virus (TMEV) is used to model human neurological conditions associated with prior viral infections, with outcomes partly attributable to improper induction and regulation of the immune response. Perfluorooctanoic acid (PFOA) can alter pathologies known to influence neurological disease such as inflammatory responses, cytokine expression, and glial activation. Co-exposure to TMEV and PFOA was used to test the hypothesis that early life exposure to the potential immunotoxicant PFOA would affect immune responses so as to render TMEV-resistant C57BL/6J (B6) mice susceptible to viral-induced neurological disease. Methods: Neonate B6 mice were exposed to different treatments: non-injected, sham-infected with PBS, and TMEV-infected, with the drinking water of each group including either 70 ppt PFOA or filtered water. The effects of PFOA were evaluated by comparing neurological symptoms and changes in immune-related cytokine and chemokine production induced by viral infection. Immune responses of 23 cytokines and chemokines were measured before and after infection to determine the effects of PFOA exposure on immune response. Results: Prior to infection, an imbalance between Th1, Th2, and Treg cytokines was observed in PFOA-exposed mice, suppressing IL-4 and IL-13 production. However, the balance was restored and characterized by an increase in proinflammatory cytokines in the non-infected group, and a decrease in IL-10 in the PFOA + TMEV group. Furthermore, the PFOA + TMEV group experienced an increase in seizure frequency and severity. Discussion: Overall, these findings provide insight into the complex roles of immune responses in the pathogenesis of virus-associated neurological diseases influenced by co-exposures to viruses and immunotoxic compounds. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are a category of persistent, non-degradable pollutants that are widespread in the environment and in humans. They have attracted considerable attention due to their high bioaccumulation, multiple toxicities, long-term stability, and, in particular, their effects on human health. Therefore, there is an urgent need for highly efficient technologies and systematic mechanisms for the degradation of PFOS and PFOA. Therefore, we summarize four mainstream technologies for the degradation of PFOS and PFOA in water and their research progress in this review, namely adsorption, advanced oxidation processes, microbial treatment, and membrane separation. Among them, adsorption technology is the earliest and relatively mature, the advanced oxidation process has relatively high treatment efficiency, there are deep and broad development prospects for microbial treatment in the future, and membrane separation technology can recycle raw materials and help to save resources. Based on the analysis of the advantages and disadvantages of the existing technologies, the development prospect of reasonable optimization technology is prospected, with a view to providing a practical scientific reference for the research and engineering practice of PFOS and PFOA pollution control in China. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFASs) and perfluoroalkyl ether carboxylic acids (PFECAs) are organic chemicals that are widely used in the manufacture of a wide range of human-made products. Many monitoring findings revealed the presence of PFASs and PFECAs in numerous environmental sources, including water, soil, and air, which drew more attention to both chemicals. Because of their unknown toxicity, the discovery of PFASs and PFECAs in a variety of environmental sources was viewed as a cause for concern. In the present study, male mice were given orally one of the typical PFASs, perfluorooctanoic acid (PFOA), and one of the representative PFECAs, hexafluoropropylene oxide-dimer acid (HFPO-DA). The liver index showing hepatomegaly rose significantly after 90 d of exposure to PFOA and HFPO-DA, respectively. While sharing similar suppressor genes, both chemicals demonstrated unique hepatotoxic mechanisms. In different ways, these two substances altered the expression of hepatic stress-sensing genes as well as the regulation of nuclear receptors. Not only are bile acid metabolism-related genes in the liver altered, but cholesterol metabolism-related genes as well. These results indicate that PFOA and HFPO-DA both cause hepatotoxicity and bile acid metabolism impairment with distinct mechanisms.

The perfluoroalkyl substances (PFAS) represent a persistent class of synthetic chemicals that spread in the environment as a result of industrialization. Due to their bioaccumulative and endocrine disruption implications, these chemicals can affect food quality and human health, respectively. In the present study, the bioconcentration and biotransformation of perfluorooctanoic acid (PFOA) in common carp (Cyprinus carpio) were evaluated in a biphasic system (exposure and depuration). Carp were continuously exposed, under laboratory conditions, to 10 (Experiment 1) and 100 (Experiment 2) µg/L PFOA for 14 weeks, followed by a wash out period of 3 weeks. Fish organs and tissues were collected at 8, 12, 14 weeks of exposure and at week 17, after the depuration period. The results obtained from the LC-MS/MS analysis showed the presence of PFOA in all studied organs. The highest values of PFOA were identified in the gallbladder (up to 2572 ng/g d.w.) in Experiment 1 and in the gallbladder (up to 18,640 ng/g d.w.) and kidneys (up to 13,581 ng/g d.w.) in Experiment 2. The average BCF varied between 13.4 and 158 L/Kg in Experiment 1 and between 5.97 and 80.3 L/Kg in Experiment 2. Four biotransformation products were identified and quantified in all organs, namely: PFBA, PFPeA, PFHxA, and PFHpA. PFBA was proven to be the dominant biotransformation product, with the highest values being determined after 8 weeks of exposure in the kidney, gallbladder, brain, liver, and gonads in both experiments. Because freshwater fish are an important food resource for the human diet, the present study showed the fishes' capacity to accumulate perfluoroalkyl substances and their metabolites. The study revealed the necessity of monitoring and risk studies of new and modern synthetic chemicals in aquatic resources. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a new type of organic pollutant in wastewater that is persistent, toxic, and accumulates in living organisms. The development of rapid and sensitive analytical methods to detect PFOA in environmental media is of great importance. Fluorescence detection has the advantages of high efficiency and low cost, in which fluorescent probes have excellent fluorescence properties, excellent bio-solubility, and remarkable photostability. It is necessary to review the fluorescence detection routes for PFOA. In addition, the up-conversion of fluorescent materials (UCNPs), as fluorescent materials to prepare fluorescent probes with, has significant advantages and also attracts the attention of researchers, however, reviews related to their application in detecting PFOA and comparing them with other routes are rare. Furthermore, there are many strategies to improve the performance of up-conversion fluorescent probes including SiO2 modification and amino modification. These strategies can enhance the detection effect of PFOA. Thus, this work reviews the types of fluorescence detection, the design, and synthesis of UCNPs, their recognition mechanism, properties, and their application progress. Moreover, the development trend and prospects of these detection probes are given. [ABSTRACT FROM AUTHOR]

Amongst per- and polyfluoroalkyl substances (PFAS) compounds, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have a high persistence in physicochemical and biological degradation; therefore, the accumulation of PFOS and PFOA can negatively affect aquatic organisms and human health. In this study, two microalgae species (Chlorella vulgaris and Scenedesmus obliquus) were exposed to different concentrations of a PFOS and PFOA mixture (0 to 10 mg L−1). With increases in the contact time (days) and the PFAS concentration (mg L−1) from 1 to 7, and 0.5 to 10, respectively, the cell viability, total chlorophyll content, and protein content decreased, and the decrease in these parameters was significantly greater in Scenedesmus obliquus. As another step in the study, the response surface methodology (RSM) was used to optimize the toxicity effects of PFAS on microalgae in a logical way, as demonstrated by the high R2 (>0.9). In another stage, a molecular docking study was performed to monitor the interaction of PFOS and PFOA with the microalgae, considering hydrolysis and the enzymes involved in oxidation-reduction reactions using individual enzymes. The analysis was conducted on carboxypeptidase in Chlorella vulgaris and on c-terminal processing protease and oxidized cytochrome c6 in Scenedesmus obliquus. For the enzyme activity, the affinity and dimensions of ligands-binding sites and ligand-binding energy were estimated in each case. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid is an artificial and non-degradable chemical. It is widely used due to its stable nature. It can enter the human body through food, drinking water, inhalation of household dust and contact with products containing perfluorooctanoic acid. It accumulates in the human body, causing potential harmful effects on human health. Based on the biodegradability and bioaccumulation of perfluorooctanoic acid in the human body, there are increasing concerns about the adverse effects of perfluorooctanoic acid exposure on kidneys. Research shows that kidney is the main accumulation organ of Perfluorooctanoic acid, and Perfluorooctanoic acid can cause nephrotoxicity and produce adverse effects on kidney function, but the exact mechanism is still unknown. In this review, we summarize the relationship between Perfluorooctanoic acid exposure and kidney health, evaluate risks more clearly, and provide a theoretical basis for subsequent research. [ABSTRACT FROM AUTHOR]

This study represents a first time that perstraction was assessed as a process to remove perfluorooctanoic acid (PFOA) from water. In the perstraction process, PFOA permeates through a membrane from water to a solvent. The membrane used in this study was polydimethylsiloxane (PDMS). The experimental approach included the following: (1) measurement of partition coefficients for PFOA between water and selected solvents; (2) determination of solubility and diffusivity of the solvents in PDMS; (3) determination of the uptake of PFOA in PDMS; (4) determination of the effects of selected particles imbedded in the PDMS on PFOA uptake and solvent absorption; and (5) demonstration of the perstraction process to remove PFOA from water. PFOA preferentially partitioned to alcohols over water. In addition, ZnO and CuO particles in PDMS significantly enhanced the rate at which PFOA was absorbed in PDMS from deionized water due to ionic interactions. The perstraction of PFOA from deionized water into hexanol was demonstrated. However, perstraction was not successful at removing PFOA from tap water. While the application of perstraction to removing PFOA from water is limited, the idea was demonstrated and information contained within this manuscript is new. [ABSTRACT FROM AUTHOR]

Soil contamination with perfluorooctanoic acid (PFOA) is a global concern. PFOA in soil can enter plants, affect plant growth and threaten food safety. Therefore, understanding the plant utilization and phytotoxicity of PFOA is conducive to assessing the environmental risk of soil contaminated with PFOA. This review analyzed recent studies about the uptake and effects of PFOA on terrestrial plants from the aspects of absorption, transport, distribution, phytotoxicity, and the underlying mechanism. Based on current research, PFOA was predominantly taken by plant roots and showed adverse effects on plants by affecting the antioxidant system and metabolic process. Research in field or higher terrestrial plants is still very scarce. Given the importance of exploring the potential remediation methods for PFOA, more research with comprehensive consideration of soil and environmental factors should be carried out to tell its specific mechanisms of plant utilization and toxicity action. [ABSTRACT FROM AUTHOR]

Research on combined phytotoxicity of perfluorooctanoic acid (PFOA) and nanoparticles is very important for the remediation of PFOA contaminated soil and further assessment for the potential of nano-enhanced phytoremediation. Here, joint effects of PFOA and CuO nanoparticles (nCuO) in plants were studied by exposing radish (Raphanus sativus L.) to PFOA (4 mg/kg) and nCuO (200 and 400 mg/kg) for 30 days, and measuring for contaminant accumulation, radish biomass, photosynthesis profiles and nutrient contents. Results showed that PFOA accumulated highly in radish organs but showed limited effects on radish biomass. nCuO could increase the transfer rate of PFOA from root to shoot and reduce PFOA accumulation in edible root part, but higher nCuO lead to decreased radish biomass. Reversely, PFOA alleviated the adverse effects of nCuO on leaf photosynthesis and root metabolism of vitamins and amino acids. These results provided basics for exploring possibility of nano-enhanced phytoremediation for PFOA soil pollution. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is an artificially synthesized perfluorinated chemical widely used in industries. It is often released into the environment without treatment, which causes pollution in groundwater. Recently, we have reported a rapid and efficient removal of PFOA in aqueous solution by using a fountain-strip dielectric barrier discharge reactor (SF-DBD). This design allows for the gaseous–liquid interaction to happen in a large space at atmospheric pressure, so it is a promising method to efficiently remove PFOA from water. Recently, we reported the effects of the process parameters, including power mode, pulse time, sinusoidal wave discharge, the discharge gas, initial concentration, pH, conductivity, and positive and negative discharges, on the efficiency of this method for PFOA degradation. Understanding the reaction mechanism is key to further improve the efficiency of the system. In this work, we reported the decomposition mechanism of the SF-DBD for PFOA degradation. The mass spectrum (MS) showed that PFOA was degraded to perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, perfluorobutanoic acid, perfluoropropionic acid, and trifluoroacetic acid after the plasma treatment. The optical emission spectroscope (OES) and the radical scavenger experiments indicated that the excited argon atoms and hydroxyl radicals played a major role in PFOA degradation, while the contributions from the solvated electrons (e−aq), superoxide anion radical (·O2−), and singlet oxygen (1O2) were negligible in initiating the cleavage reaction. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is an artificially synthesized per-fluorinated chemical widely used in industry. It is often released into the environment without treatment and causes pollution in groundwater. In this paper, we employed a strip fountain dielectric barrier discharge (SF-DBD) plasma source to degrade PFOA from the water. The effects of power supply mode, discharge gases, pH, the conductivity of the solution, concentration, etc., on the degradation efficiency were studied. For a 200 mL sample of 75 mg/L PFOA, a 99% degradation efficiency with a 204.5 μg/kJ energy production rate was achieved using an average power of 43 W negative pulse argon plasma for 50 min at atmospheric pressure. The total organic carbon concentration (TOC) decreased by 63% after a 60 min treatment. The SF-DBD proves to be a promising and energy-saving technique to efficiently remove PFOA from water. [ABSTRACT FROM AUTHOR]

• Electrochemical Sensing of PFOA with Nanoenabled Functionalized electrodes. • Highly sensitive and selective PFOA sensor with 24 ppt LOD and 80 LOQ. • Sensor is stable over at least 200 cycles with 97 % reproducibility. • Detection in matrices with interferents shows a 100 ± 10 % recovery. • Proposed mechanism to explain the electrochemical reduction of PFOA. Perfluorooctanoic acid (PFOA) is a pollutant of emerging concern due to its high persistence, bioaccumulation, and potential toxicity. Numerous studies report its presence in water sources, soils, and food at sub-ppb levels. Here, we describe the design of an electrochemical sensor based on a self-assembled monolayer (SAM) of the 1H,1H,2H,2H -Perfluorodecanethiol (PFDT), into gold nanoparticles (AuNPs) electrodeposited on glassy carbon electrode (GCE) for PFOA detection. The GCE coated with AuNPs was characterized using scanning electron microscopy (SEM). The average size of AuNPs is estimated as 16 nm ± 07 nm, and the electrode surface coverage is 39 % ± 2%. The calculated coverage of (Γ*) of chemisorbed PFDT molecules was found to be 8.26 × 10−10 mol cm−2. PFOA electroanalysis and quantification were performed by square wave adsorptive cathodic stripping voltammetry (SW-AdCSV) and measurements were verified by liquid chromatography-tandem mass spectrometry LC/MS-MS. We worked in a range of 100 to 5000 ppt, the PFOA concentration has a linear relationship with the stripping current (R2 = 0.996). The limits of detection (LOD) and quantification (LOQ) are 24 and 80 ppt, respectively. Analyses of tap and brackish samples performed by spiking tap water with known PFOA concentrations show precision and accuracy above 95%. The nano-enabled electrode is stable for at least 200 cycles. The reproducibility across similarly prepared but different electrodes is above 97%. The sensor shows the ability to quantify PFOA even in a matrix with other perfluoroalkyl substances as interferents, with a recovery percentage (Δi 0 –Δi int)/Δi 0) within of 100 ± 10%. [ABSTRACT FROM AUTHOR]

A 3-D transport and dispersion model was applied to study the recent past and future dynamics of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) concentrations in the Black Sea for the 2016–2030 period. The modelled surface concentrations show a distinct seasonal behaviour, shaped by winter to spring convective mixing. A significant increasing long-term trend in PFOS concentrations is established, with concentrations in water layers 200 m below the surface increasing at 4–8% per year. Driving mechanisms for PFOA and PFOS transport and accumulation in the subsurface and deeper layers are the cooling of the surface water in winter and the transport of water masses from the North Western Shelf (NWS) of the Black Sea. A simulated 50% phase-out of PFOA and PFOS from 2020 to 2030 shows a 21% reduction in PFOA, while PFOS continues to increase. • Recent past and future distributions of PFOA and PFOS in the Black Sea are simulated. • A key mechanism for removing dissolved substances is proposed. • Modelling suggests mean PFOS concentration in the Black Sea is above 0.18 μg m−3. • More than a 50% reduction in PFOS imports is needed to prevent its future increase. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) and atrazine are two endocrine disruptors that are widely found in waters. Negative effects of PFOA and atrazine have been studied individually, but few data have focused on their combined effects. Here, zebrafish embryos were used as model to investigate the combined toxicity of PFOA and atrazine. The acute toxicity of atrazine (11.9 mg/L) to zebrafish embryos was much higher than that of perfluorooctanoic acid (224.6 mg/L) as shown by the 120h-LC 50 value. Developmental effects, including delayed yolk sac absorption, spinal curvature, and liver abnormalities, were observed in both one- and two-component exposures. Notably, the rate of embryonic malformations in the co-exposure group was more than twice as high as that of single component exposure in the concentration range of 1/8-1/2 EC 50 , which indicated a synergistic effect of the binary mixture. The synergistic effect of PFOA-atrazine was further validated by combinatorial index (CI) modeling. In addition, changes of amino acid metabolites, reactive oxygen species and superoxide dismutase indicated that oxidative stress might be the main pathway for enhanced toxicity under co-exposure condition. Overall, co-exposure of PFOA and atrazine resulted in stronger developmental effects and more complicated amino acid metabolic response toward zebrafish, compared with single component exposure. [Display omitted] • Atrazine and PFOA induced yolk sac, liver and spinal abnormalities in zebrafish. • Atrazine and PFOA act in synergistic manner when inducing developmental toxicity. • Oxidative stress might be a main pathway mediating the toxic enhancement. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) have already drawn a lot of attention for their accumulation and reproductive toxicity in organisms. Perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), two representative PFAS, are toxic to humans and animals. Due to their widespread use in environmental media with multiple toxicities, PFOA and PFOS have been banned in numerous countries, and many substitutes have been produced to meet market requirements. Unfortunately, most alternatives to PFOA and PFOS have proven to be cumulative and highly toxic. Of the reported multiple organ toxicities, reproductive toxicity deserves special attention. It has been confirmed through epidemiological studies that PFOS and PFOA are not only associated with reduced testosterone levels in humans, but also with an association with damage to the integrity of the blood testicular barrier. In addition, for women, PFOA and PFOS are correlated with abnormal sex hormone levels, and increase the risk of infertility and abnormal menstrual cycle. Nevertheless, there is controversial evidence on the epidemiological relationship that exists between PFOA and PFOS as well as sperm quality and reproductive hormones, while the evidence from animal studies is relatively consistent. Based on the published papers, the potential toxicity mechanisms for PFOA, PFOS and their substitutes were reviewed. For males, PFOA and PFOS may produce reproductive toxicity in the following five ways: (1) Apoptosis and autophagy in spermatogenic cells; (2) Apoptosis and differentiation disorders of Leydig cells; (3) Oxidative stress in sperm and disturbance of Ca2+ channels in sperm membrane; (4) Degradation of delicate intercellular junctions between Sertoli cells; (5) Activation of brain nuclei and shift of hypothalamic metabolome. For females, PFOA and PFOS may produce reproductive toxicity in the following five ways: (1) Damage to oocytes through oxidative stress; (2) Inhibition of corpus luteum function; (3) Inhibition of steroid hormone synthesis; (4) Damage to follicles by affecting gap junction intercellular communication (GJIC); (5) Inhibition of placental function. Besides, PFAS substitutes show similar reproductive toxicity with PFOA and PFOS, and are even more toxic to the placenta. Finally, based on the existing knowledge, future developments and direction of efforts in this field are suggested. [Display omitted] [ABSTRACT FROM AUTHOR]

The International Agency for Research on Cancer (IARC) classifies PFOA as a Class 1 carcinogen. Here, a new naked-eye PFOA immunochromographic strip was developed to recognize PFOA in domestic water and real human samples within 10 min based on a novel custom designed anti-PFOA monoclonal antibody (mAb) 2A3, which was firstly an immune rapid detection method for PFOA has been proposed. Using computer simulation techniques such as quantum computing to assist in designing the structural formula of PFOA semi antigen, which hapten was firstly proposed. The half maximal inhibitory concentration of PFOA monoclonal antibody (mAb) 2A3 was 2.4 μg/mL. Using mAb 2A3, we developed an immunochromatographic strip (ICS) for detecting PFOA in real samples. The developed method generated results in 10 min, with visual detection limits of 20, 20, and 200 μg/mL and limit of detection of 50, 200, and 500 μg/mL for water, blood and urine samples, respectively. The established ICS and indirect competitive enzyme-linked immunosorbent assay were used to analyze the actual samples, and the results were confirmed by LC-MS/MS. Our study findings showed that the ICS and ic-ELISA can quickly detect PFOA in actual samples. [Display omitted] • A new hapten of perfluorooctanoic acid was synthesized successfully. • The rapid strip biosensor was firstly established for perfluorooctanoic acid. • The visual cut-off values for perfluorooctanoic acid was 20 μg/mL. • The strip assay can be applied for on-site monitoring of water and human samples. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate oxidative stress induced by perfluorooctanoic acid (PFOA) in the brain and liver tissues of Balb/c mice as well as protective effects of taurine and coenzyme Q10 (CoQ10) in both organs. For this purpose, animals were treated with PFOA (15 and 30 mg/kg) orally and their lipid peroxidation, total glutathione levels (GSH), and antioxidant enzyme activities measured and both tissues analysed for histopathological changes. Our results showed a dose-dependent decrease in body weight and increase in relative brain and liver weights, PFOA-induced lipid peroxidation and reduced glutathione peroxidase (GPx) activity in the brain tissue, and changes in GSH levels, GPx, superoxide dismutase (Cu-Zn SOD), and catalase (CAT) activities in the liver tissue. Pre-treatment with taurine or CoQ10 provided protection against PFOA-induced Cu-Zn SOD reduction in the liver tissue. Our findings evidence the depleting effect of PFOA on antioxidative systems and confirm that PFOA exerts its (neuro)toxicity through oxidative stress, but further research is needed to identify the exact toxicity mechanisms, especially in the brain. [ABSTRACT FROM AUTHOR]

Detailed in vitro studies on the effects of perfluorooctanoic acid (PFOA) have demonstrated that activation of peroxisome proliferator-activated receptor a (PPARa) is a key process by which PFOA affects the malignancy of estrogen receptor a (ERa)-positive breast cancer cells. However, there is very little information on the PPARa-regulated genes responsible for the effects of PFOA in ERa-negative breast cancer cell malignancy. We recently demonstrated that fatty acid 2-hydroxylase (FA2H) stimulates the migration of ERa-negative human MDA-MB-231 cells, and PPARa is a key factor for the induction of FA2H in these cells. However, evidence for the relationship between PFOA exposure and PPARa-FA2H axis-driven migration has not been obtained. Here we analyzed the effects of PFOA on PPARa transcription and FA2H expression in relation to MDA-MB-231 cell migration. We found that simultaneously with stimulated migration, PFOA upregulated FA2H and activated the transcription of PPARa. FA2H-selective siRNA, but not siRNA control, clearly dampened PFOA-mediated cell migration. There is an inhibitory interaction between PPARa and PPARß/d (i.e., PPARß/d can suppress PPARa-mediated transcription) in MDA-MB-231 cells, but even in the presence of PPARß/d expression, PFOA appeared to free PPARa to upregulate FA2H. Collectively, our findings show that i) PFOA activates PPARa-mediated transcription, ii) PFOA stimulates migration dependent on FA2H expression, and iii) mechanistically, PFOA relieves PPARß/d suppression of PPARa activity to upregulate FA2H in MDA-MB-231 cells. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) enables trace-detection for biosensing and environmental monitoring. Optimized enhancement of SERS can be achieved when the energy of the localized surface plasmon resonance (LSPR) is close to the energy of the Raman excitation wavelength. The LSPR can be tuned using a plasmonic superstructure array with controlled periods. In this paper, we develop a new technique based on laser near-field reduction to fabricate a superstructure array, which provides distinct features in the formation of periodic structures with hollow nanoclusters and flexible control of the LSPR in fewer steps than current techniques. Fabrication involves irradiation of a continuous wave laser or femtosecond laser onto a monolayer of self-assembled silica microspheres to grow silver nanoparticles along the silica microsphere surfaces by laser near-field reduction. The LSPR of superstructure array can be flexibly tuned to match the Raman excitation wavelengths from the visible to the infrared regions using different diameters of silica microspheres. The unique nanostructure formed can contribute to an increase in the sensitivity of SERS sensing. The fabricated superstructure array thus offers superior characteristics for the quantitative analysis of fluorescent perfluorooctanoic acid with a wide detection range from 11 ppb to 400 ppm. [ABSTRACT FROM AUTHOR]

With the restricted use of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), a number of alternatives to PFOS and PFOA have attracted great interest. Most of the alternatives are still characterized by persistence, bioaccumulation, and a variety of toxicity. Due to the production and use of these substances, they can be detected in the atmosphere, soil and water body. They affect human health through several exposure pathways and especially enter the gut by drinking water and eating food, which results in gut toxicity. In this review, we summarized the effects of PFOS, PFOA and 9 alternatives on pathological changes in the gut, the disruption of physical, chemical, biological and immune barriers of the intestine, and the gut-organ axis. This review provides a valuable understanding of the gut toxicity of PFOS, PFOA and their alternatives as well as the human health risks of emerging contaminants. [Display omitted] • PFOS, PFOA and their alternatives cause pathological alterations in the gut. • PFOS, PFOA and their alternatives disrupt the four intestinal barriers. • PFOS, PFOA and their alternatives affect the gut-brain axis and gut-liver axis. • Some alternatives cause greater intestinal damages than PFOS and PFOA. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PFAS removal performance with different iron minerals were discussed in CWs. • Iron minerals reduced PFAS content in water and substrate and promoted plant uptake. • Iron minerals increased the EPS capacitance and promoted electron transfer in CWs. • Gene relate to EPS synthesis and defluorination were enriched in iron-based CWs. Perfluorooctanoic acid (PFOA) and perfluorooctane sulphonic acid (PFOS) pollution existed widely in constructed wetlands (CWs). Iron minerals have been proved to enhance PFOS and PFOA removal in CWs. However, the microbial extracellular electron transfer mechanisms mediated by iron minerals remain unclear. To strengthen the removal of PFOA and PFOS, and explore the mechanisms, in this study, four kinds of iron-based CWs were constructed with magnetite, siderite, sponge iron, and hematite. Results reflected that the addition of iron minerals increased the PFOS and PFOA removal by 7.27 %-16.42 % than that in control group. XRD and XPS results show that iron minerals can promote the formation of Fe(Ⅲ) (hydrogen)oxides that conducive to electron transfer. The electrochemical characterization of extracellular polymer (EPS) and microbial electron transport activity showed that iron minerals improve the capacitance and electron transfer properties of EPS. Microbial results showed that magnetite and siderite improved the diversity of microorganisms that associated with PFOA and PFOS degradation (e.g. Geobacter, Shewanella, and Pseudomonas). Furthermore, both magnetite and siderite can promote extracellular protein secretion (p < 0.05), and increase the abundance of genes that related to extracellular-related cytochrome synthesis pathway (K02275, K01784), EPS synthesis (pgi, pgm, ugp), and defluorine (K01560, K01561, K01563). This study provides insight into the mechanisms of the PFOA and PFOS removal process and contributes a new perspective to further enhance the treatment of new pollutants in CWs. [ABSTRACT FROM AUTHOR]

Perfluorinated compounds (PFCs), organofluoride compounds comprising carbon–fluorine and carbon–carbon bonds, are used as water and oil repellents in textiles and pharmaceutical tablets; however, they are associated with potential neurotoxic effects. Moreover, the impact of PFCs on neuronal survival, activity, and regulation within the brain remains unclear. Additionally, the mechanisms through which PFCs induce neuronal toxicity are not well-understood because of the paucity of data. This study elucidates that perfluorooctanoic acid (PFOA) and perfluoroheptanoic acid (PFHpA) exert differential effects on the survival and activity of primary cortical neurons. Although PFOA triggers apoptosis in cortical neurons, PFHpA does not exhibit this effect. Instead, PFHpA modifies dendritic spine morphogenesis and synapse formation in primary cortical neuronal cultures, additionally enhancing neural activity and synaptic transmission. This research uncovers a novel mechanism through which PFCs (PFHpA and PFOA) cause distinct alterations in dendritic spine morphogenesis and synaptic activity, shedding light on the molecular basis for the atypical behaviors noted following PFC exposure. Understanding the distinct effects of PFHpA and PFOA could guide regulatory policies on PFC usage and inform clinical approaches to mitigate their neurotoxic effects, especially in vulnerable population. [Display omitted] • PFOA induces cortical neuron apoptosis. • PFHpA induces spontaneous neural network activity in cortical neuron cultures. • PFCs (PFHpA or PFOA) affect dendritic spine and synapse formation in cortical neuron cultures. • PFC exposure differentially changes gene expression in primary cortical neurons. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2D MOFs-based nanosheets with rich oxygen vacancies were designed. • The Kirkendall effect successfully regulated the oxygen vacancies. • The presence of oxygen vacancies improved the photocatalytic ability of the cathode. • PFOA degradation and TOC removal efficiency reached 93 % and 92 % in 180 min. • The mechanism of adsorption and degradation of PFOA in heterogeneous systems was described clearly. In heterogeneous solar photo-electro-Fenton (SPEF) degradation of perfluorooctanoic acid (PFOA), improving the binding energy between the catalyst and PFOA on a surface molecular level to facilitate absorption, diffusion, and degradation is a great challenge. Herein, we attained this goal in two steps: First, developing of two-dimensional (2D) MOFs-based CoFe nanosheets with layered structures as photo-electrocatalysts, which own abundant unsaturated coordination sites to accelerate rapid mass transport and charge transfer. Secondly, the construction of abundant oxygen vacancies (OVs) at low temperatures in 2D CoFe causes hybridization of the d-band of Fe and LUMO orbital of O in PFOA, enhancing PFOA's binding capacity by theoretical analysis. OVs also reduced the band gap of CoFe and increased the efficiency of electron-hole separation, thereby improving photo-electrocatalytic activity and enabling rapid degradation of PFOA. Moreover, it can maintain a good degradation effect in complex ionic background conditions and actual water samples. These findings extend the applications of catalysts and consolidate the effect of OVs on photo-electrocatalysis for wide environmental applications. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a widely used industrial compound that has been found to induce intestinal toxicity. However, the underlying mechanisms have not been fully clarified and effective interventions are rarely developed. Inulin, a prebiotic, has been used as a supplement in human daily life as well as in gastrointestinal diseases and metabolic disorders. In this study, male mice were exposed to PFOA with or without inulin supplementation to investigate the enterotoxicity and potential intervention effects of inulin. Mice were administered PFOA at 1 mg/kg/day, PFOA with inulin at 5 g/kg/day, or Milli-Q water for 12 weeks. Histopathological analysis showed that PFOA caused colon shortening, goblet cell reduction, and inflammatory cell infiltration. The expression of the tight junction proteins ZO-1, occludin and claudin5 significantly decreased, indicating impaired barrier function. According to the RNA-sequencing analysis, PFOA exposure resulted in 917 differentially expressed genes, involving 39 significant pathways, such as TNF signaling and cell cycle pathways. In addition, the protein expression of TNF-α, IRG-47, cyclinB1, and cyclinB2 increased, while Gadd45γ, Lzip, and Jam2 decreased, suggesting the involvement of the TNF signaling pathway, cell cycle, and cell adhesion molecules in PFOA-associated intestinal injury. Inulin intervention alleviated PFOA-induced enterotoxicity by activating the PI3K/AKT/mTOR signaling pathway and increasing the protein expression of Wnt1, β-catenin, PI3K, Akt3, and p62, while suppressing MAP LC3β, TNF-α, and CyclinE expression. These findings suggested that PFOA-induced intestinal injury, including inflammation and tight junction disruption, was mitigated by inulin through modifying the PI3K/AKT/mTOR signaling pathways. Our study provides valuable insights into the enterotoxic effects of PFOA and highlights the potential therapeutic role of inulin. [Display omitted] • PFOA induced intestinal inflammation and tight junction disruption. • TNF pathway and cell cycle protein were implicated in PFOA-related enterotoxicity. • Inulin restored the intestinal injury by activating the PI3K/AKT/mTOR pathway. [ABSTRACT FROM AUTHOR]

Even though the endocrine-disrupting potential of perfluorooctanoic acid (PFOA) is well known, the mechanisms underlying its cellular and epigenetic toxicity at the critical stage of hypothalamic development are poorly understood. This is why we studied its effects on the embryonic mouse hypothalamic cell line N46 (mHypoE-N46) with a hope to shed more light on the mechanisms through which PFOA causes embryonic hypothalamic cell damage. To do that, we studied cell viability, global DNA methylation, and gene expression in cells exposed to PFOA. As the PFOA dose increased, cell viability decreased, while global DNA methylation increased. PFOA also significantly altered the expression of genes related to the apoptosis and cell cycle, neurotrophic genes, and the Tet, Dnmt, and Mecp2 genes. Our findings suggest that exposure to PFOA affects cell survival through the reprogramming of embryonic hypothalamic DNA methylation patterns and altering cell homeostasis genes. DNA methylation and changes in the Mecp2 gene expression induced by PFOA also imply wider ramifications, as they alter genes of other major mechanisms of the embryonic hypothalamus. Our study may therefore serve as a good starting point for further research into the mechanisms of PFOA effect of hypothalamic development. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a prevalent, persistent organic pollutant (POP) in the environment. The potential toxic impacts of PFOA on human and ecological health is becoming an increasing concern worldwide. In this study, we investigated the acute toxicity of PFOA in terms of growth, mortality, lifespan, neurobehaviour, fecundity and livelihood in Caenorhabditis elegans (C. elegans), a free-living ecologically important animal model species. The acute toxicity (LC50) of PFOA was found to be 4.42 µM (1.83 mg/L). PFOA exposure induced alteration in locomotor behaviour in C. elegans. The reproduction capacity of C. elegans was also reduced after exposure to 0.1 µM (41.4 µg/L) PFOA. Similarly, developmental toxicity was also documented with the reduction in lifespan and alteration in chemotaxis plasticity above 1 µM (414 µg/L) PFOA. C. elegans bioaccumulated PFOA about 520 times than the surrounding concentration when exposed to 0.41 ug/L PFOA. Given that PFOA has demonstrated its toxicological impacts on the reproductive capacity and lifespan of C. elegans at the concentrations that are commonly found at contaminated areas, it is likely that the contamination of PFOA will have detrimental effects on the food chain in both terrestrial and aquatic ecosystems. Thus, the results of this study have significant implications for the ecological risk assessment and remediation of PFOA.

[Display omitted] • A novel CN layer coated flower-like WO 3 /W photoanode was successfully synthesized. • The photoelectrode exhibited sunlight-driven photocatalytic and reusability. • The photoelectrode used to degrade PFOA and generate electricity. • A new electron transfer channel is constructed due to the formation of W–N–C bond. • The PFOA degradation mechanism and decomposion pathway were analyzed. Photoelectrocatalysis (PEC) system has been proven to be effective in degrading perfluorooctanoic acid (PFOA) and generating electricity as a goal to solve the problems of environmental pollution and energy shortages simultaneously. In this study, we utilized a flower-like WO 3 in-situ generated on tungsten foil (WO 3 /W), and then doped with a CN layer by immersing it in urea solution and then undergoing calcination (CN-WO 3 /W), to degrade PFOA and generate electricity. The growth mechanism of WO 3 /W with different morphologies prepared under various experimental conditions was analyzed in order to explain the reasons for the superior performance of the flower-like structure compared to other morphologies. Under the irradiation of simulated sun-light, the power density reached its peak at 0.11 mW/cm2 when current density was 0.14 mA/cm2 with PFOA as fuel. CN-WO 3 /W displayed a steady state photocurrent density of 6.1 mA/cm2 at 1.2 V (vs. Ag/AgCl) under simulated sun-light irradiation and a high PFOA degradation of 95 %, which is much higher than that of WO 3 /W. Due to distinctive flower-like structure, stable W–N–C bond, narrower energy band (from 2.67 to 2.41 eV), more acquisition of visible light, and strong oxidation capability, the CN-WO 3 /W exhibited high stability and reusability for simultaneous PEC degradation of PFOA (almost unchanged after 9 cycles) and electricity generation (without activity loss during the 24 h test) under simulated sun-light irradiation. Based on the scavenger-quenching experiments the possible degradation pathways of PFOA were suggested. This work provides a way to design and synthesize the photoanode to construct reaction system for high-performance photocatalytic PFOA degradation and electricity generation. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA), a synthetic alkyl chain fluorinated compound, has emerged as a persistent organic pollutant of grave concern, casting a shadow over both ecological integrity and humans. Its insidious presence raises alarms due to its capacity to bioaccumulate within the human liver, potentially paving the treacherous path toward liver cancer. Yet, the intricate mechanisms underpinning PFOA's role in promoting the growth of hepatocellular carcinoma (HCC) remain shrouded in ambiguity. Here, we determined the proliferation and transcription changes of HCC after PFOA exposure through integrated experiments including cell culture, nude mice tests, and colony-forming assays. Based on our findings, PFOA effectively promotes the proliferation of HCC cells within the experimental range of concentrations, both in vivo and in vitro. The proliferation efficiency of HCC cells was observed to increase by approximately 10% due to overexposure to PFOA. Additionally, the cancer weight of tumor-bearing nude mice increased by 87.0% (p < 0.05). We systematically evaluated the effects of PFOA on HCC cells and found that PFOA's exposure can selectively activate the PI3K/AKT/mTOR/4E-BP1 signaling pathway, thereby playing a pro-cancer effect on HCC cells Confirmation echoed through western blot assays and inhibitor combination analyses. These insights summon a response to PFOA's dual nature as both an environmental threat and a promoter of liver cancer. Our work illuminates the obscured domain of PFOA-induced hepatoxicity, shedding light on its ties to hepatocellular carcinoma progression. [Display omitted] • PFOA can promote the proliferation of liver cancer in vitro and in vivo. • PFOA exposure caused changes in expression of various oncogenes in liver cancer. • MTOR pathway plays a significant role in liver cancer caused by PFOA. • PFOA decreased the sensitivity of liver cancer to mTOR inhibitors. [ABSTRACT FROM AUTHOR]

Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), as emerging endocrine-disrupting chemicals (EDCs), pose adverse effects on aquatic organisms. Conventional ecological risk assessment (ERA) not fully considering the mode of toxicity action of PFOS and PFOA, may result in an underestimation of risks and confuse decision-makers. In the study, we developed species sensitivity weighted distribution (SSWD) models based on adverse outcome pathway (AOP) networks for deriving predicted no-effect concentrations (PNECs). Three kinds of weighting criteria (intraspecies variation, trophic level abundance, and data quality) and weighted log-normal distribution methods were adopted. The developed models considered the inter/intraspecies variation and integrated nontraditional endpoints of endocrine-disrupting effects. The PNECs of endocrine disruption effects were derived as 2.52 μg/L (95% confidence intervals 0.667–9.85 μg/L) for PFOS and 18.7 μg/L (5.40–71.0 μg/L) for PFOA, which were more conservative than those derived from the SSD method and were comparable with the values in the literature based on the chronic toxicity data. For PFOS, the effect of growth and development was the most sensitive; however, for PFOA, the effect of reproduction was the most sensitive in the effects of growth and development, reproduction, biochemistry and genetics, and survival. The endocrine-disrupting effects of PFOS and PFOA are significant and need to be fully recognized in the ERA. This study provided an ERA framework that can improve the ecological relevance and reduce the uncertainty of PNECs of EDCs. [Display omitted] • SSWD considers the inter/intraspecies variation and data quality of toxicity. • AOP network integrates endocrine disruption effects of muti-biological levels. • PNECs of endocrine disruption effects as 2.52 (PFOS) and 18.7 (PFOA) μg/L. • SSWD-based PNECs are more conservative than those from SSD models. • AOP-SSWD improves ecological relevance and reduce uncertainty of PNEC. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) has been widely utilized, leading to serious contamination. Iron (hydr)oxide transformation was varied in media. Whereas, dynamic transformation effect was extensively unclear. Here, iron (hydr)oxide dynamic transformation-induced PFOA transport and attenuation was investigated by emphasizing initial goethite (α -FeOOH) and associated minerals content and groundwater type based on the multi-process attenuation model. Results revealed that groundwater type did not affect the PFOA attenuation pathway. However, it controlled the iron (hydr)oxide dynamic transformation differences. PFOA transport behavior (retardation factor R from 2.61 to 1.91) was significantly affected by iron (hydr)oxide dynamic transformation. Iron (hydr)oxide transformation induced the greatest PFOA transport risk (R = 1.91, attenuation rate λ = 0.0001 min−1) in SO 4 2− environment, where complex α -FeOOH, Fe 3 O 4 , and β -Fe 2 O 3 ·H 2 O transformed to simplex β -FeOOH, leading to instantaneous (K d) and kinetic (α) two-site sorption fraction change. Furthermore, the associated mineral Fe 3 O 4 of goethite was crucial in PFOA attenuation (λ from 0.0001 to 0.0002 min−1). Fe 3 O 4 released Fe2+ and the oxidation of Fe2+ to Fe3+ provided electrons, facilitating the formation of F–(CF 2) 7 –COO· radicals, which played a key role in the following cycle attenuation process. This study provides a theoretical basis for understanding the interaction mechanism of PFOA and iron (hydr)oxide dynamic transformation under groundwater differences. [Display omitted] • Associated mineral Fe 3 O 4 (releasing Fe2+) of goethite plays a key role in PFOA attenuation. • Groundwater type control iron (hydr)oxide dynamic transformation differences. • PFOA transport behavior is significantly affected by iron (hydr)oxide dynamic transformation. • Iron (hydr)oxide transformation induces the greatest PFOA transport risk in SO 4 2− groundwater. • SO 4 2− environment-induce α -FeOOH, Fe 3 O 4 , and β -Fe 2 O 3 ·H 2 O transform to β -FeOOH. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) constitute a large group of compounds that are water, stain, and oil repellent. Numerous sources contribute to the blood levels of PFAS in the European population. The main contributor for perfluorooctanoic acid (PFOA) is food, house dust, consumer products and personal care products (PCPs). The purpose of the present work is to calculate the dietary and dermal external exposure to PFOA, estimate the aggregated internal exposure from diet and PCPs using a PBPK model, and compare estimates with measured concentrations. Detailed information on diet and PCP use from the EuroMix study is combined with concentration data of PFOA in food and PCPs in a probabilistic exposure assessment. A physiologically based pharmacokinetic model (PBPK) was further refined by incorporating a dermal exposure pathway, and changes in the kidney and faecal excretion. The aggregated internal exposure using the PBPK model shows that the major contributor to the internal exposure is diet for both males and females. The estimated internal exposure of PFOA for the EuroMix population was in the same range but lower than the measured blood concentrations using the lower bound (LB) external exposure estimates, showing that the LB estimates are underestimations. For seven females the internal exposure of PFOA were higher from PCPs than from diet. PCPs and diet contributed in the same range to the internal PFOA exposure for several women participating in EuroMix. This calls for additional studies on exposure to PFOA and possibly other PFAS from PCPs, especially for women. Overall, PBPK modelling was shown as valuable tool in understanding the sources of PFOA exposure and in guiding risk assessments and regulatory decisions. • The aggregated internal exposure to PFOA using the PBPK model shows that the major contributor to the internal exposure is diet. • For seven females the internal exposure of PFOA were higher from PCPs than from diet. • Our work demonstrates the importance of creating awareness of among PCP users, especially women, on the potential PFAS exposure from PCPs. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous throughout the United States. Previous studies have shown PFAS exposure to be associated with a reduced immune response. However, the relationship between serum PFAS and antibody levels following SARS-CoV-2 infection or COVID-19 vaccination has not been examined. We examined differences in peak immune response and the longitudinal decline of antibodies following SARS-CoV-2 infection and COVID-19 vaccination by serum PFAS levels in a cohort of essential workers in the United States. We measured serum antibodies using an in-house semi-quantitative enzyme-linked immunosorbent assay (ELISA). Two cohorts contributed blood samples following SARS-CoV-2 infection or COVID-19 vaccination. We used linear mixed regression models, adjusting for age, race/ethnicity, gender, presence of chronic conditions, location, and occupation, to estimate differences in immune response with respect to serum PFAS levels. Our study populations included 153 unvaccinated participants that contributed 316 blood draws over a 14-month period following infection, and 860 participants and 2451 blood draws over a 12-month period following vaccination. Higher perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) concentrations were associated with a lower peak antibody response after infection (p = 0.009, 0.031, 0.015). Higher PFOS, perfluorooctanoic acid (PFOA), PFHxS, and PFNA concentrations were associated with slower declines in antibodies over time after infection (p = 0.003, 0.014, 0.026, 0.025). PFOA, PFOS, PFHxS, and PFNA serum concentrations prior to vaccination were not associated with differences in peak antibody response after vaccination or with differences in decline of antibodies over time after vaccination. These results suggest that elevated PFAS may impede potential immune response to SARS-CoV-2 infection by blunting peak antibody levels following infection; the same finding was not observed for immune response to vaccination. • Effect of serum PFAS on immune response to COVID-19 examined here. • Found relationship between serum PFAS and post-SARS-CoV-2 infection immune response. • High serum PFAS concentration may dampen response to SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel biochar modified by wet ball-milling with FeCl 3 and pyrolysis. • Modified biochar has dispersed Fe0/Fe 3 C, multi-stage pores, and graphitized carbon. • PFAS sorption is enhanced by pore-filling, electrostatic and hydrophobic interaction. • PFBA sorption on Fe/C composite depends more on electrostatic interaction than PFOA. • Our novel sorbent excellent co-removal of various chain length PFAS in natural water. Legacy long-chain per-/polyfluoroalkyl substances (PFAS) are being replaced by short-chain homologs, which have been widely detected in the environment. To achieve the co-removal of different chain length PFAS, this study systematically explored the single and synergistic effects of FeCl 3 -impregnation, wet ball-milling and different carbonization temperatures on the surface chemistry and pore structures of different biochars as well as sorption performances and mechanisms towards long-chain perfluorooctanoic acid (PFOA) and short-chain perfluorobutyric acid (PFBA). As a consequence, we presented a new method to synthesize magnetic sorbents by wet ball-milling with FeCl 3 solution and high-temperature carbonization. Through this process, we tailored a magnetic porous Fe-doped graphitized biochar (named Fe-M−BC 900) that contains abundant dispersed positive iron sites with stable Fe0/Fe 3 C, multi-stage pore structure, highly hydrophobic graphite-like carbon, and O-containing functional groups. Fe-M−BC 900 exhibited a high sorption capacity of 10.1 mg PFBA/g and 39.1 mg PFOA/g. PFAS sorption on Fe-M−BC 900 was mainly governed by pore-filling, electrostatic interaction, and hydrophobic partitioning. The sorption of PFBA on Fe-doped biochars depends more on electrostatic interaction and is less affected by hydrophobic partitioning compared to PFOA. Finally, we demonstrated that Fe-M−BC 900 performed high co-removal rates (>96 %) for a wide range of legacy and emerging PFAS with different chain lengths and functional groups in natural waters (∑PFAS: 142 ∼ 265 μg/L) and simulated wastewater (∑PFAS: 600 μg/L), with a high relative sorption capacity of > 91 %, even after four consecutive recycling processes. This new adsorbent could help water facilities comply with upcoming PFAS regulations if tested on a larger scale. [ABSTRACT FROM AUTHOR]

Owing to the strong C–F bond in nature and the rigidity of the poly-fluoroalkyl chain, perfluorooctanoic acid (PFOA) is difficult to be eliminated by reactive species and microbes in environments, thus posing a serious threat to ecosystems. Vitamin B 12 as a cofactor for enzymes, and biochar as the electron providers and conductors, were integrated to enhance PFOA biodegradation. The raw material of biochar was the sludge after dewatering by adding 50 mg/g DS of Fe(III). After pyrolysis under high temperature (800 °C), biochar (SC800) detected high content of Fe(II) (197.64 mg/g) and abundant oxygen-containing functional groups, thus boosting PFOA biodegradation via donating electrons. 99.9% of PFOA could be removed within 60 d as 0.1 g/L SC800 was presented in the microbial systems containing vitamin B 12. Moreover, vitamin B 12 facilitated the evolution of Sporomusa which behaved the deflorination. Via providing reactive sites and mediating direct inter-species electron transfer (DIET), SC800 boosted PFOA biodegradation. Corresponding novel results in the present study could guide the development of bioremediation technologies for PFOA-polluted sites. [Display omitted] • Sporomusa initiated PFOA biodegradation via cometabolic reductive dehalogenation. • Vitamin B 12 enabled the evolution of Sporomusa for PFOA biodegradation. • Biochar-mediated DIET promoted Sporomusa to achieve 99.9% of PFOA removal. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) present in various water sources have raised a serious concern on their health risk worldwide. Anion exchange is known to be one of the effective treatment methods but the resin properties suitable for theses contaminants have not been fully understood. We examined four commercially available anion exchange resins with different properties (DIAION™ PA312, HPA25M, UBA120, and WA30) and one polymer-based adsorbent (HP20), for their PFOA and PFOS removal in the batch experiment. All or a part of the selected resins were further characterized for their functional group, surface morphology and pore size distribution. The 72 h batch experiment with the 100 mg/L PFOA or PFOS in the laboratory pure water matrix showed a superior capacity of the strong base anion exchange resins, the porous-type HPA25M and PA312, and the gel-type UBA120, for PFOA removal (92.6–97.9%). Among those resins, the high porous HPA25M was suggested most effective due to its remarkably high reaction rate and effectiveness to PFOS (99.9%). In the groundwater matrix, however, the performance of the those anion exchange resins was generally suppressed, causing up to 71% decrease in their removal rates. The least matrix impact was observed for PFOS removal by HPA25M, which indicated the resin's high selectivity to the contaminant. The physiochemical analysis indicated that the presence of relatively large pores (1 nm–10 nm) over HPA25M played an important role in the PFAS removal. [Display omitted] • Anion exchange resins with different properties were examined for PFOA and PFOS removal from different water matrix. • The high porous strong base anion exchange resin was most effective in adsorption capacity and rate. • Groundwater matrix had a larger impact on tested resins in PFOA removal than in PFOS removal. • Large pores with 1∼10 nm size may contribute efficient and robust PFOS removal from groundwater. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl acids (PFAAs) are persistent, synthetic compounds that are used in a number of consumer products. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been associated with cardiovascular risk factors, and changes in gene expression and DNA methylation in animals and cellular systems. However, whether PFAA exposure is associated with LINE-1 DNA methylation, a potential marker of cardiovascular risk, in humans remains unknown. We sought to evaluate the cross-sectional associations between serum PFAAs and LINE-1 DNA methylation in a population highly exposed to PFOA. We measured serum PFAAs twice four to five years apart in 685 adult participants (47% male, mean age±SD=42±11years). We measured percent LINE-1 DNA methylation in peripheral blood leukocytes at the second time point (follow-up), and estimated absolute differences in LINE-1 methylation associated with an interquartile (IQR) shift in mean PFAA serum levels. IQR increases in mean serum PFOA, PFOS, perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) were associated with differences of -0.04 (p=0.16), 0.20 (p=0.001), 0.06 (p=0.19), and 0.02 (p=0.57), respectively, in % LINE-1 methylation at follow-up after adjustment for potential confounders. We observed a monotonic increase in LINE-1 DNA methylation across tertiles of PFOS and PFNA (ptrend=0.02 for both associations), but not across tertiles of PFOA or PFHxS (ptrend=0.71 and 0.44, respectively). In summary, serum PFOS was associated with LINE-1 methylation, while serum PFOA, PFHxS, and PFNA were not. Additional research is needed to more precisely determine whether these compounds are epigenetically active.