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This study explores the impact of environmental pollutants on nuclear receptors (CAR, PXR, PPARα, PPARγ, FXR, and LXR) and their heterodimerization partner, the Retinoid X Receptor (RXR). Such interaction may contribute to the onset of non-alcoholic fatty liver disease (NAFLD), which is initially characterized by steatosis and potentially progresses to steatohepatitis and fibrosis. Epidemiological studies have linked NAFLD occurrence to the exposure to environmental contaminants like PFAS. This study aims to assess the simultaneous activation of nuclear receptors via perfluorooctanoic acid (PFOA) and RXR coactivation via Tributyltin (TBT), examining their combined effects on steatogenic mechanisms. Mice were exposed to PFOA (10 mg/kg/day), TBT (5 mg/kg/day) or a combination of them for three days. Mechanisms underlying hepatic steatosis were explored by measuring nuclear receptor target gene and lipid metabolism key gene expressions, by quantifying plasma lipids and hepatic damage markers. This study elucidated the involvement of the Liver X Receptor (LXR) in the combined effect on steatosis and highlighted the permissive nature of the LXR/RXR heterodimer. Antagonistic effects of TBT on the PFOA-induced activation of the Pregnane X Receptor (PXR) and Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) were also observed. Overall, this study revealed complex interactions between PFOA and TBT, shedding light on their combined impact on liver health. [ABSTRACT FROM AUTHOR]

Perfluorooctane sulfonate (PFOS) is a prominent perfluorinated compound commonly found in the environment, known to pose various risks to human health. However, the removal of PFOS presents significant challenges, primarily due to the limited discovery of bacteria capable of effectively degrading PFOS. Moreover, single degradation bacteria often encounter obstacles in individual cultivation and the breakdown of complex pollutants. In contrast, microbial consortia have shown promise in pollutant degradation. This study employed a continuous enrichment method, combined with multiple co-metabolic substrates, to investigate a microbial consortium with the potential for PFOS degradation. By employing this methodology, we effectively identified a microbial consortium that demonstrated the capacity to reduce PFOS when exposed to an optimal concentration of methanol. The consortium predominantly comprised of Hyphomicrobium species (46.7%) along with unclassified microorganisms (53.0%). Over a duration of 20 days, the PFOS concentration exhibited a notable decrease of 56.7% in comparison to the initial level, while considering the exclusion of adsorption effects. Furthermore, by comparing the predicted metabolic pathways of the microbial consortium with the genome of a known chloromethane-degrading bacterium, Hyphomicrobium sp. MC1, using the KEGG database, we observed distinct variations in the metabolic pathways, suggesting the potential role of the unclassified microorganisms. These findings underscore the potential effectiveness of a "top-down" functional microbial screening approach in the degradation of stubborn pollutants. [ABSTRACT FROM AUTHOR]

Exposure to poly- and perfluoroalkyl substances (PFASs) can result in bioaccumulation. Initial findings suggested that PFASs could accumulate in tissues rich in both phospholipids and proteins. However, our current understanding is limited to the average concentration of PFASs or phospholipid content across entire tissue matrices, leaving unresolved the spatial variations of lipid metabolism associated with PFOA in zebrafish tissue. To address gap, we developed a novel methodology for concurrent spatial profiling of perfluorooctanoic acid (PFOA) and individual phospholipids within zebrafish hepatic tissue sections, utilizing matrix-assisted laser desorption/ionization time of flight imaging mass spectrometry (MALDI-TOF-MSI). 5-diaminonapthalene (DAN) matrix and laser sensitivity of 50.0 were optimized for PFOA detection in MALDI-TOF-MSI analysis with high spatial resolution (25 μm). PFOA was observed to accumulate within zebrafish liver tissue. H&E staining results corroborating the damage inflicted by PFOA accumulation, consistent with MALDI MSI results. Significant up-regulation of 15 phospholipid species was observed in zebrafish groups exposed to PFOA, with these phospholipid demonstrating varied spatial distribution within the same tissue. Furthermore, co-localized imaging of distinct phospholipids and PFOA within identical tissue sections suggested there could be two distinct potential interactions between PFOA and phospholipids, which required further investigation. The MALDI-TOF-IMS provides a new tool to explore in situ spatial distributions and variations of the endogenous metabolites for the health risk assessment and ecotoxicology of emerging environmental pollutants. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is used in a variety of industries and is highly persistent in the environment, with potential human health risks. Photocatalysis has been extensively used for the decomposition of various organic pollutants, yet its simulation and modeling are challenging. This research aimed to establish different machine learning (ML) algorithms which can simulate and predict the photocatalytic degradation of PFOA. The published results were used to estimate and predict the photocatalytic degradation of PFOA. Statistical criteria including the coefficient of determination (R2), mean absolute error (MAE), and mean squared error (MSE) were considered in assessing the best method of modeling. Among the seven ML algorithms pre-screened, Adaptive Boosting (AdaBoost), Gradient Boosting Machine (GBM), and Random Forest (RF) showed the best performance and were chosen for deep modeling and analysis. Grid search was used to optimize the models developed by AdaBoost, GBM, and RF; and permutation variable importance (PVI) was used to analyze the relative importance of different variables. Based on the modeling results, GBM model (R2 = 0.878, MSE = 106.660, MAE = 6.009) and RF model (R2 = 0.867, MSE = 107.500, MAE = 6.796) showed superior performances compared with AdaBoost model (R2 = 0.574, MSE = 388.369, MAE = 16.480). Furthermore, the PVI results suggested that the GBM model provided the best outcome, with the light irradiation time, type of catalyst, dosage of catalyst, solution pH, irradiation intensity, initial PFOA concentration, oxidizing agents (peroxymonosulfate, ammonium persulfate, and sodium persulfate), irradiation wavelength, and solution temperature as the most important process variables in decreasing order. [ABSTRACT FROM AUTHOR]

Cold plasma is gaining increasing attention as a novel tool to activate energy demanding chemical processes, including advanced reduction/oxidation processes (AROPs) of organic pollutants in water. The very complex milieu generated by discharges at the water/plasma interface comprises photons, strong oxidants and strong reductants which can be exploited for achieving the degradation of most any kind of pollutants. Despite the complexity of these systems, the powerful arsenal of mechanistic tools and chemical probes of physical organic chemists can be usefully applied to understand and develop plasma chemistry. Specifically, the added value of air plasma generated by in situ discharge with respect to ozonation (ex situ discharge) is demonstrated using phenol and various phenol derivatives and mechanistic evidence for the prevailing role of hydroxyl radicals in the initial attack is presented. On the reduction front, the impressive performance of cold plasma in inducing the degradation of recalcitrant perfluoroalkyl substances, which do not react with OH radicals but are attacked by electrons, is reported and discussed. The widely different reactivities of perfluorooctanoic acid (PFOA) and of perfluorobutanoic acid (PFBA) underline the crucial role played in these processes by the interface between plasma and solution and the surfactant properties of the treated pollutants. [ABSTRACT FROM AUTHOR]

The influence of solution electrical conductivity and ion composition on the performance of plasma reactors for water treatment applications is only partially understood. This study uses a point–point discharge over the surface of water in argon gas to determine the influence of solution conductivity, in the range of 0.3–45 mS/cm, on the physiochemical properties of spark discharges and the removal of two organic contaminants: perfluorooctanoic acid (PFOA) and Rhodamine B dye. The influence of various ions was also explored using chlorine and non-chlorine salts to adjust solution conductivity. The removal of PFOA increased with conductivity regardless of the salt type due to the salting out effect which increased PFOA's interfacial concentration. The removal of Rhodamine B dye depended on both salt type and solution electrical conductivity. In the presence of non-chorine salts, UV photolysis was the main mechanism for the dye degradation and its removal rate did not change with conductivity. The dye removal rate was the highest in the presence of chloride-based salts at the highest values of solution conductivities. In the presence of chorine salts, OH radicals are produced by the discharge generated hypochlorous acid, which is mixed into the bulk solution to react with the Rhodamine B dye. The generation rate of hydroxyl radicals appears to decrease with increasing solution conductivity, and these species are not directly involved in the degradation of the two compounds investigated in this study. [ABSTRACT FROM AUTHOR]

As a short-chain PFAS (per- and polyfluoroalkyl substance), GenX was produced in recent years to replace traditional long-chain PFASs, such as perfluorooctanoic acid (PFOA). However, GenX turns out to be more toxic than people originally thought, posing health risks as a persistent environmental pollutant. In this research, for the first time, we incorporated chlorella, a single-celled green freshwater microalga that grows worldwide, with polyacrylonitrile (PAN) in equal amounts in electrospun nanofibers and studied the capability of the electrospun PAN/Algae bicomponent nanofibrous membrane (ES(PAN/Algae)) to bind and remove GenX from water. The incorporation of algae demonstrated a synergistic effect and significantly improved the GenX removal efficiency of the nanofibrous membrane. The maximum GenX removal capacity reached 0.9 mmol/g at pH 6, which is significantly higher than that of most of the reported GenX adsorbents as well as activated carbon. The GenX removal mechanism was investigated and discussed by using water contact angle, zeta potential, FTIR, and XPS techniques. This research demonstrated the potential to make highly efficient adsorbent/filter materials from common and economic materials to practically remediate short-chain PFASs from various water bodies. [ABSTRACT FROM AUTHOR]

Water organic pollution has become a major issue. A large number of people suffer from the decline in water quality. In addition, polluted water can lead to health problems or excessive deaths. In this regard, an increasingly important method for efficient water treatment is electrocoagulation (EC), the technology that encompasses a small equipment size combined with a simple operation compared to other water treatment methods. The importance of EC is especially accentuated by the recent decarbonization efforts due to the increasing availability of renewable electricity systems. This review provides an overview of the most recent developments in EC technology as it pertains to wastewater treatment. The EC is preferred for organic wastewater treatment over other traditional treatment methods due to its easy setup and low material costs. Moreover, the EC is very powerful in destabilizing organic impurities by charge neutralization and then coagulating to form flocs. In addition, EC has shown high efficiency not only in removing various organic pollutants but also in emerging persistent contaminants, such as microplastics. For these reasons, the EC mechanisms and related functional modalities are reviewed, as well as extensive details are provided on the diversity of the removed contaminants. Overall, this review provides significant new knowledge of interest for environmental chemical researchers in particular and engineers in general on the details of the EC technology for wastewater treatment and water purification. [ABSTRACT FROM AUTHOR]

The globally widespread perfluorooctanoic acid (PFOA) is a concerning environmental contaminant, with a possible toxic long-term effects on the environment and human health The development of sensible, rapid, and low-cost detection systems is a current change in modern environmental chemistry. In this context, two triamine-based chemosensors, L1 and L2, containing a fluorescent pyrene unit, and their Zn(II) complexes are proposed as fluorescent probes for the detection of PFOA in aqueous media. Binding studies carried out by means of fluorescence and NMR titrations highlight that protonated forms of the receptors can interact with the carboxylate group of PFOA, thanks to salt bridge formation with the ammonium groups of the aliphatic chain. This interaction induces a decrease in the fluorescence emission of pyrene at neutral and slightly acidic pH values. Similarly, emission quenching has also been observed upon coordination of PFOA by the Zn(II) complexes of the receptors. These results evidence that simple polyamine-based molecular receptors can be employed for the optical recognition of harmful pollutant molecules, such as PFOA, in aqueous media. [ABSTRACT FROM AUTHOR]

Cardiovascular disease (CVD) poses the leading threats to human health and life, and their occurrence and severity are associated with exposure to environmental pollutants. Per- and polyfluoroalkyl substances (PFAS), a group of widely used industrial chemicals, are characterized by persistence, long-distance migration, bioaccumulation, and toxicity. Some PFAS, particularly perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS), have been banned, leaving only legacy exposure to the environment and human body, while a number of novel PFAS alternatives have emerged and raised concerns, such as polyfluoroalkyl ether sulfonic and carboxylic acid (PFESA and PFECA) and sodium p-perfluorous nonenoxybenzene sulfonate (OBS). Overall, this review systematically elucidated the adverse cardiovascular (CV) effects of legacy and emerging PFAS, emphasized the dose/concentration-dependent, time-dependent, carbon chain length-dependent, sex-specific, and coexposure effects, and discussed the underlying mechanisms and possible prevention and treatment. Extensive epidemiological and laboratory evidence suggests that accumulated serum levels of legacy PFAS possibly contribute to an increased risk of CVD and its subclinical course, such as cardiac toxicity, vascular disorder, hypertension, and dyslipidemia. The underlying biological mechanisms may include oxidative stress, signaling pathway disturbance, lipid metabolism disturbance, and so on. Various emerging alternatives to PFAS also play increasingly prominent toxic roles in CV outcomes that are milder, similar to, or more severe than legacy PFAS. Future research is recommended to conduct more in-depth CV toxicity assessments of legacy and emerging PFAS and explore more effective surveillance, prevention, and treatment strategies, accordingly. [ABSTRACT FROM AUTHOR]

Perfluorinated alkyl substances (PFAS) are ubiquitous environmental contaminants that are widely used in consumer products and fire suppression foams. The presence of PFAS in ground and surface water can create a route for PFAS to enter the soil, exposing ecosystems (including agroecosystems), where they will move through the food web via biomagnification. The toxicity of PFAS to plants, particularly in agricultural ecosystems, is of emerging concern due to the application of biosolids that are often contaminated with PFAS. Nevertheless, due to the low concentrations of PFAS in most agricultural soils, the direct impact of PFAS on plant health is not well understood. We used 1H‐nuclear magnetic resonance (NMR) metabolomics to explore the effects of exposure of two key PFAS, perfluorooctanoic acid and perfluorooctanesulfonic acid, on Arabidopsis thaliana, a model organism. We found that Arabidopsis exhibited an accumulation of multiple metabolites, including soluble sugars (glucose and sucrose), multiple amino acids, and tri‐carboxylic acid (TCA) cycle intermediates, suggesting that PFAS exposure impacts the metabolism of plants by causing an accumulation of stress‐related amino acids and soluble sugars that drives increased activity of the TCA cycle. The present study shows that 1H‐NMR metabolomics is a viable tool for investigating changes in the metabolic profile of plants exposed to PFAS and can be used to illuminate the stress response of plants in a high‐throughput, nonbiased manner. Environ Toxicol Chem 2023;42:663–672. © 2022 SETAC [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a persistent compound which is associated with many negative effects on human health. In this study, possible oxidative stress inducing effects of PFOA and protective effects of taurine and coenzyme Q10 (CoQ10) in lung, heart and testes of mice were investigated. Animals were administered 15 and 30 mg/kg doses of PFOA orally for 10 days. All three organ weights were found to be affected in response to PFOA while taurine seemed to be effective against absolute heart weight reduction. PFOA was also found to induce histopathological changes in lung tissue. 15 mg/kg of PFOA reduced catalase (CAT) activity in lung; increased malondialdehyde (MDA) and total glutathione (GSH) levels, activities of superoxide dismutase (Cu-Zn SOD) and CAT in heart; and increased GSH levels and reduced Cu-Zn SOD and CAT activities in testes. On the other hand, 30 mg/kg PFOA treatment led to Cu-Zn SOD activity increase in lung; GSH level and Cu-Zn SOD activity increase in heart; and reduction of all three enzyme activities in testes. Taurine was found to be protective against Cu-Zn SOD activity increase in both lung and heart tissues, as well as against reduction of glutathione peroxidase (GPx) and CAT activities in the testes. CoQ10 seemed to protect against PFOA-induced increases in MDA levels in the heart tissue. These results suggest the oxidative stress involvement in the toxicity mechanism of an important environmental pollutant, PFOA, in lung, heart and testes of mice. Moreover, taurine and CoQ10 have protective role to some extent against PFOA-induced toxicity. [ABSTRACT FROM AUTHOR]

The extensive use of petrochemicals has produced serious environmental pollution problems; fortunately, bioremediation is considered an efficient way to fight against pollution. In line with Synthetic Biology is that robust microbial chassis with an expanded ability to remove environmental pollutants are desirable. Pseudomonas putida KT2440 is a robust lab microbe that has preserved the ability to survive in the environment and is the natural host for the self‐transmissible TOL plasmid, which allows metabolism of toluene and xylenes to central metabolism. We show that the P. putida KT2440 (pWW0) acquired the ability to use octane as the sole C‐source after acquisition of an almost 62‐kb ICE from a microbial community that harbours an incomplete set of octane metabolism genes. The ICE bears genes for an alkane monooxygenase, a PQQ‐dependent alcohol dehydrogenase and aldehyde dehydrogenase but lacks the electron donor enzymes required for the monooxygenase to operate. Host rubredoxin and rubredoxin reductase allow metabolism of octane to octanol. Proteomic assays and mutants unable to grow on octane or octanoic acid revealed that metabolism of octane is mediated by redundant host and ICE enzymes. Octane is oxidized to octanol, octanal and octanoic acid, the latter is subsequently acylated and oxidized to yield acetyl‐CoA that is assimilated via the glyoxylate shunt; in fact, a knockout mutant in the aceA gene, encoding isocitrate lyase was unable to grow on octane or octanoic acid. [ABSTRACT FROM AUTHOR]

In this study, a novel granular activated carbon (GAC) gravity-driven membrane (GDM) hybrid system with a ceramic membrane was developed for the production of high quality water. The operational performance in water permeability; removal of organic matter; and contaminants of emerging concern (CECs) including microplastics, larvae, and perfluorinated compounds (i.e., perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid(PFOS)) was evaluated. The experimental results indicate that the GAC-GDM hybrid system can overcome the limitations of the GAC (i.e., low rejection efficiency of particulates) and GDM (i.e., low rejection efficiency of organics) processes. The GDM process showed higher removal rates of microplastics and larvae than the GAC process (i.e., 77.9% and 100% vs. 16.6% and 70%, respectively), and the GAC process exhibited higher removal rates of organic matter and perfluorinated compounds (PFOA and PFOS) than the GDM process (i.e., 54.8%, 90.9% and 99.1% vs. 17.6%, 23% and 31.8%, respectively). In the GAC-GDM hybrid system, stable water flux was observed with the efficient removal of CECs and organic matter during operation. This study implies that the GAC-GDM system can be used as a distributed water treatment system in remote areas such as islands and mountains because the GAC-GDM system is able to minimize the operation scale. [ABSTRACT FROM AUTHOR]

Environmental contaminants perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are present in human serum at the highest concentration among all per- and polyfluoroalkyl substances (PFAS). Serum concentrations as high as 500 ng and 3000 ng PFOA/ml have been detected in individuals living near contamination sites and those occupationally exposed, respectively. Animal and human studies indicated that PFOA and PFOS at these serum concentrations perturb the immune system. The aim of this study was to examine the effects of in vitro exposure of human peripheral blood mononuclear cells (PBMC) to 1, 10, or 100 µM PFOA or PFOS in a medium with serum (RPMI-1640 + 5% human AB serum) on the measurement of proliferation, T cell activation, generation of memory T cells, and cytokine production/secretion. In addition, these immune system parameters were assessed for PBMC in a serum-free medium (OpSFM), which was stimulated with phytohemagglutinin (PHA) (2.5 µg/ml) or influenza vaccine antigen (0.625 µg/ml Flu Ag). PFOS decreased proliferation stimulated by PHA or Flu Ag. With Flu Ag stimulation, PFOA and PFOS inhibited the generation of memory T cells in a concentration-dependent manner. In OpSFM, PFOA and PFOS produced no marked change in proliferation and no inhibition of T cell activation. Cytokines measured in the media with Luminex methodology indicated decreased PBMC secretion of IFN-γ by PFOA and PFOS in medium with serum, but no alteration in OpSFM. The results indicated that changes in immune parameters due to PFOA or PFOS following Flu Ag stimulation are medium (±serum) dependent. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are recognized as emerging environmental pollutants due to their high persistence and toxicities to humans and animals. Understanding the temporal trend of PFAS in the environment is important for their pollution control and making appropriate policies. Many studies have reported the PFAS concentrations in Taihu Lake, the third largest lake in China, while their temporal trend during the years was seldom investigated. This study summarizes the PFAS concentrations in the water, sediment and organisms in Taihu Lake from 2009 to 2020 to depict their temporal trends. Meanwhile, the ecological model of AQUATOX was applied to evaluate and predict the potential risks of PFAS from 2012 to 2030. The results showed that the total PFAS concentrations varied but without distinct increase or decrease in both water and sediment during the years, while PFAS concentrations in organisms significantly decreased. The yearly mean concentrations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in the water were 21.7–25.4 ng/L and 9.7–26.5 ng/L respectively, lower than the Standards for Drinking Water Quality of China and the suggested water quality criteria to protect the aquatic organisms. In sediment, PFOA and PFOS concentrations were 0.16–0.69 ng/g and 0.15–0.82 ng/g respectively, much lower than the recommended sediment quality guideline values. Based on the AQUATOX prediction, there will be no major threats caused by PFAS to the growth of biota in Taihu Lake in the near future, while the biomass of some species (e.g. carp) will be affected under the perturbation of PFAS. Both field investigation and AQUATOX simulation showed that PFOS concentrations in invertebrates and fish descend steadily, while no remarkable decrease in PFOA concentrations was expected. This study suggests a decreasing ecological risk of PFAS in Taihu Lake, while highlights the necessity of continuous monitoring of PFAS contamination. [Display omitted] • No distinct increase in PFAS concentrations is observed in water and sediment. • PFOA and PFOS concentrations are lower than the environmental quality standards. • PFOS in organisms are descending steadily base on investigation and model prediction. [ABSTRACT FROM AUTHOR]

• TOF quantified in 38 of 40 sample locations. • TOF captures up to 98 % more organic fluorine than target LC-MS/MS. • High TOF does not correlate to high quantified PFAS concentrations and vice-versa. Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants of concern due to their long persistence in the environment, toxicity, and widespread presence in humans and wildlife. Knowledge regarding the extent of PFAS contamination in the environment is limited due to the need for analytical methods that can reliably quantify all PFAS , since traditional target methods using liquid chromatography (LC)-mass spectrometry (MS) fail to capture many. For a more comprehensive analysis, a total organic fluorine (TOF) method can be used as a screening tool. We combined TOF analysis with target LC-MS/MS analysis to create a statewide PFAS hotspot map for surface waters throughout South Carolina. Thirty-eight of 40 locations sampled contained detectable concentrations of organic fluorine (above 100 ng/L). Of the 33 target PFAS analyzed using LC-MS/MS, the most prevalent were perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA), and perfluorohexanesulfonate (PFHxS). On average, LC-MS/MS only accounted for 2 % of the TOF measured. Locations with high TOF did not necessarily correlate to high total quantified PFAS concentrations and vice-versa, demonstrating the limitations of target PFAS analysis and indicating that LC-MS may miss highly contaminated sites. Results suggest that future surveys should utilize TOF to more comprehensively capture PFAS in water bodies. [Display omitted] [ABSTRACT FROM AUTHOR]

Fourteen legacy organochlorine (OC) contaminants and 12 perfluoroalkyl substances (PFASs) were measured in eggs of tawny owls (Strix alueco) in central Norway (1986–2019). We expected OCs to have reached stable equilibrium levels due to bans, and that recent phase‐out of some PFASs would have slowed the increase of these compounds. ∑OC comprised on average approximately 92% of the measured compounds, whereas ∑PFAS accounted for approximately 8%. However, whereas the ∑OC to ∑PFAS ratio was approximately 60 in the first 5 years of the study, it was only approximately 11 in the last 5 years. Both OC pesticides and polychlorinated biphenyls (PCBs) showed substantial declines over the study period (~85%–98%): hexachlorocyclohexanes and chlordanes seemed to be levelling off, whereas p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE) and hexachlororbenzene (HCB), and most PCB congeners still seemed to decline at a more or less constant rate. While the concentration of perfluorooctane sulfonic acid (PFOS), the dominating PFAS, was reduced by approximately 43%, other perfluorinated sulfonates (PFSAs) showed only minor changes. Moreover, the median concentrations of seven perfluorinated carboxylic acids (PFCAs) increased approximately five‐fold over the study period. Perfluorononanoic acid and perfluoroundecanoate acid, however, seemed to be levelling off in recent years. In contrast, perfluorododecanoic acid, perfluorodecanoate acid, perfluorotridecanoic acid, and perfluorotetradecanoic acid seemed to increase more or less linearily. Finally, perfluorooctanoic acid (PFOA) was increasingly likely to be detected over the study period. Hence, most legacy OCs and PFOS have not reached a lower threshold with stable background levels, and voluntary elimination of perfluoroalkyl carboxylates still has not resulted in declining levels in tawny owls in central Norway. Environ Toxicol Chem 2022;41:1508–1519. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States. Perfluorooctanoic acid (PFOA), a persistent environmental pollutant, has been shown to induce pancreatic acinar cell tumors in rats. Human epidemiologic studies have linked PFOA exposure to adverse chronic health effects including several types of cancer. Previously, we demonstrated that PFOA induces oxidative stress and focal ductal hyperplasia in the mouse pancreas. Here, we evaluated whether PFOA promotes pancreatic cancer using the LSL-KRasG12D;Pdx-1 Cre (KC) mouse model of pancreatic cancer. KC mice were exposed to 5 ppm PFOA in drinking water starting at 8 weeks of age and analyzed at 6 and 9 months of age. At the 6-month time point, PFOA exposure increased pancreatic intraepithelial neoplasia (PanIN) area by 58%, accompanied by a 2-fold increase in lesion number. Although PanIN area increased at 9 months, relative to 6 months, no treatment effect was observed. Collagen deposition was enhanced by PFOA at both the 6- and 9-month time points. PFOA also induced oxidative stress in the pancreas evidenced by elevated antioxidant activity of superoxide dismutase (Sod), catalase and thioredoxin reductase, and a ~3-fold increase in Sod1 mRNA and protein levels at 6 months. Although antioxidant activity was not enhanced by PFOA exposure at the 9-month time point, increased pancreatic oxidative damage was observed. Collectively, these results show that PFOA elicited temporal increases in PanIN lesion area and desmoplasia concomitant with the induction of oxidative stress, demonstrating that it functions to promote pancreatic cancer progression. [ABSTRACT FROM AUTHOR]

The History of PFAS Litigation and Current Trends in Emerging Lawsuits The origins of PFAS litigation. Litigation involving PFAS has ballooned in recent years, suggesting that PFAS-related litigation could be akin to asbestos litigation. Per- and polyfluoroalkyl substances (PFAS) are manufactured chemicals used around the globe and have left a lasting impact on our planet. Introduction to PFAS Invented in the 1940s and entering mainstream production in the 1950s, some estimate over 4,700 chemicals exist in the PFAS family, and the number of PFAS chemicals grows by the year.2 This includes the widely known perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), GenX, and thousands more. [Extracted from the article]

Contamination and adverse effects from various pollutants often appear in abandoned industrial regions. Thus, nine groundwater samples were collected from the vicinity of the fluorochemical industry in Fuxin City, Liaoning Province, to determine concentrations of the ten heavy metals arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), manganese (Mn), zinc (Zn), iron (Fe) and mercury(Hg), as well as those of fluorine (F−) and eighteen poly- and perfluorinated substances (PFASs), analyse correlation relationships, and assess the health risks for different age groups. The results showed that the levels of fluorine (F−) (0.92–4.42 mg·L−1), Mn (0.0005–4.91 mg·L−1) and Fe (1.45–5.61 mg·L−1) exceeded the standard limits for drinking water. Short chain perfluorobutanoic acid (PFBA) (4.14–2501.42 ng·L−1), perfluorobutane sulfonate (PFBS) (17.07–51,818.61 ng·L−1) and perfluorohexanoic acid (PFHxA) (0.47–936.32 ng·L−1) were the predominant substances from the PFASs group. No individual PFASs levels had significant relationships with F− or heavy metal contents. There was a positive relationship between short chain PFASs concentrations and water depth and a negative relationship between long chain PFASs concentration and water depth. The hazard quotient (HQ) decreased in the order F− > heavy metals > PFASs and also decreased for older age groups. In addition, As, Fe, Mn and perfluorooctanoic acid (PFOA) were the main sources of risk from the heavy metal and PFASs groups, respectively. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is a widespread environmental pollutant of the perfluoroalkyl substance (PFAS) class that is extremely resistant to environmental and metabolic degradation, leading to bioaccumulation. PFOA exposure has been linked to many health effects including endocrine disruption and metabolic dysregulation, but our understanding of the molecular mechanisms resulting in these outcomes remains incomplete. One target affected by PFOA is the ligand regulated nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) which plays a critical role in controlling metabolic homeostasis through regulating processes such as adipogenesis, glucose homeostasis, inflammation and osteogenesis. It has been previously established that PFOA activates PPARγ through binding to the PPARγ ligand binding domain (PPARγ LBD) leading to increased expression of PPARγ controlled target genes. However, the mechanism by which PFOA achieves this has remained elusive. Here, we employed a combination of X-ray crystallography and fluorescence polarization assays to provide a structural basis for PFOA mediated activation of PPARγ via binding to the PPARγ LBD. Using X-ray crystallography, the cocrystal structure of the PPARγ LBD:PFOA complex was solved. This revealed that PFOA occupies three distinct sites, two within the PPARγ LBD and one within the activation function 2 (AF2) on the protein surface. Structural comparison of PFOA binding with previously reported PPARγ:ligand complexes supports that PFOA activates PPARγ by a partial agonist mechanism at micromolar concentrations. Fluorescence polarization assays also revealed that PFOA binding to the AF2 is unlikely to occur in a cellular context and confirmed that PFOA behaves as a partial agonist in vitro , weakly recruiting a coactivator peptide to the AF2 of the PPARγ LBD. This discovery provides an advancement in understanding PFOA mediated regulation of PPARγ, giving new insight regarding regulation of PPARγ by PFAS and PFAS substitutes in general and can be applied to the design and assessment of safer PFAS. [Display omitted] • The molecular interactions of PFOA and PPARγ were revealed by X-ray crystallography. • Three distinct PFOA binding sites were observed in the PPARγ ligand binding domain. • PFOA behaves as a partial agonist of PPARγ by a Helix 12 independent mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poly- and perfluoroalkyl substances are among the pollutants of environmental concern. • An LCMS method was developed to monitor PFOA and PFOS in sediments. • The ∑ PFOA in the surface sediment samples collected was 7.50 ng/g dw. • The total concentration of PFOS in the sediments was 2.79 ng/g dw. Poly- and perfluoroalkyl substances (PFAS) are among the pollutants of environmental concern besides pharmaceuticals and personal care products, microplastics, and other persistent organic pollutants. Of all the different PFASs reportedly present in the environment, the most researched are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). In this study, these pollutants were detected using a precise, selective, and sensitive liquid chromatographic-electrospray ionization single quadrupole mass spectrometric (LC-ESI–Q-MS) method within a linear range of 0.002–0.02 μg/mL. The method developed was thereafter validated according to the ICH validation parameters. This method was used to monitor PFOA and PFOS in selected surface sediments collected within the environs of two prominent rivers in the KwaZulu-Natal province of South Africa: Umgeni and Palmiet Rivers. While the PFOA levels varied from not detected to 1.490 ng/g dw, and PFOS levels ranged from 0.206 ng/g dw to 0.426 ng/g dw, the total PFOA and PFOS concentration (∑ PFOA and ∑ PFOS) in the surface sediment samples collected were 7.50 ng/g dw and 2.79 ng/g dw, respectively. The percent positive occurrence of PFOA and PFOS in all the tested sediment samples was 81.8 % and 100 %, respectively. This study becomes an eye opener to the commencement of research works with respect to developing remediation strategies for the removal of PFAS in the environment, especially the African environment. [ABSTRACT FROM AUTHOR]

Certain environmental chemicals affect the body's energy balance and are known as metabolism disrupting chemicals (MDCs). MDCs have been implicated in the development of metabolic diseases, such as obesity and type 2 diabetes. In contrast to their well-known impact on developing adipocytes, MDC effects leading to altered energy balance and development of insulin resistance in mature white adipocytes, constituents of adult adipose tissue, are largely unclear. Here, we investigated the effects of six well-established environmental MDCs (bisphenol A (BPA), perfluorooctanoic acid (PFOA), triclosan (TCS), p,p-dichlorodiphenyl-dichloroethylene (ppDDE), tributyltin chloride (TBT) and triphenyl phosphate (TPP)) on mature human white adipocytes derived from mesenchymal stem cells in vitro. We aimed to identify biomarkers and sensitive endpoints of their metabolism disrupting effects. While most of the tested exposures had no effect on adipocyte glucose consumption, lipid storage and assessed gene expression endpoints, the highest concentration of triclosan affected the total lipid storage and adipocyte size, as well as glucose consumption and mRNA expression of the glucose transporter GLUT1, leptin and adiponectin. Additionally, an increased expression of adiponectin was observed with TPP and the positive control PPARγ agonist rosiglitazone. In contrast, the lipidomic analysis of the cell culture medium after a 3-day exposure was extremely sensitive and revealed concentration-dependent changes in the extracellular lipidome of adipocytes exposed to nearly all studied chemicals. While some of the extracellular lipidome changes were specific for the MDC used, some effects were found common to several tested chemicals and included increases in lysophosphatidylcholines, glycerophospholipids and ceramides and a decrease in fatty acids, with possible implications in inflammation, lipid and glucose uptake. This study points to early signs of metabolic disruption and likely systemic effects of mature adipocyte exposure to environmental chemicals, as well as to the need to include lipidomic endpoints in the assessment of adverse effects of MDCs. [Display omitted] • Certain environmental contaminants are metabolism disrupting chemicals (MDCs). • MDCs strongly change extracellular lipidome of mature white adipocytes in vitro. • Changes indicate possible systemic effects and implication in metabolic diseases. • In addition, triclosan affects energy balance, and endocrine function of adipocytes. • MDCs could cause adverse effects in the white adipose tissue of adults. [ABSTRACT FROM AUTHOR]

Introduction: Poly-/per-fluoroalkyl substances (PFAS) are widespread environmental pollutants that may induce metabolic perturbations in humans, including particularly alterations in lipid profiles. Prenatal exposure to PFAS can cause lasting effects on offspring metabolic health, however, the underlying mechanisms are still unknown. Objectives: The goal of the study was to investigate the impact of prenatal PFAS exposure on the lipid profiles in cord blood. Methods: Herein, we combined determination of bile acids (BAs) and molecular lipids by liquid chromatography with ultra-high-resolution mass spectrometry, and separately quantified cord blood concentrations of sixteen PFAS in a cohort of Chinese infants (104 subjects) in a cross-sectional study. We then evaluated associations between PFAS concentration and lipidome using partial correlation network analysis, debiased sparse partial correlation, linear regression analysis and correlation analysis. Results: PFAS levels showed significant associations with the lipid profiles; specifically, PFAS exposure was positively correlated with triacylgycerols (TG) and several bile acids. Importantly, exposure to perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) were associated with increased levels of TGs with saturated fatty acids while multiple classes of phospholipids were decreased. In addition, several free fatty acids showed significant positive correlations with PFOS. Conclusions: Our results indicated that prenatal exposure to PFAS mediated metabolic changes, which may explain the associations reported between PFAS exposure and metabolic health later in life. [ABSTRACT FROM AUTHOR]

Male hypogonadism is a clinical syndrome caused by testosterone deficiency. Hypogonadism can be caused by testicular disease (primary hypogonadism) or hypothalamic-pituitary dysfunction (secondary hypogonadism). The present strategy for treating hypogonadism is the administration of exogenous testosterone. But exogenous testosterone is reported to have negative side effects including adverse cardiovascular events and disruption of physiological spermatogenesis probably due to its inability to mimic the physiological circadian rhythm of testosterone secretion in vivo. In recent years, a growing number of articles demonstrated that stem Leydig cells (SLCs) can not only differentiate into functional Leydig cells (LCs) in vivo to replace chemically disrupted LCs, but also secrete testosterone in a physiological pattern. The proliferation and differentiation of SLCs are regulated by various factors. However, the mechanisms involved in regulating the development of SLCs remain to be summarized. Factors involved in the regulation of SLCs can be divided into environmental pollutants, growth factors, cytokine and hormones. Environmental pollutants such as Perfluorooctanoic acid (PFOA) and Triphenyltin (TPT) could suppress SLCs proliferation or differentiation. Growth factors including FGF1, FGF16, NGF and activin A are essential for the maintenance of SLCs self-renewal and differentiation. Interleukin 6 family could inhibit differentiation of SLCs. Among hormones, dexamethasone suppresses SLCs differentiation, while aldosterone suppresses their proliferation. The present review focuses on new progress about factors regulating SLC's proliferation and differentiation which will undoubtedly deepen our insights into SLCs and help make better clinical use of them. [ABSTRACT FROM AUTHOR]

We studied the ability of a bacterial strain isolated from soil contaminated by chemical waste to use perfluorooctane sulfonate (PFOS) as the sole source of carbon and energy. Based on the combination of cultural, morphological, physiological and biochemical characteristics, 16S rRNA gene analysis, and phylogenetic data analysis, we identified the isolated strain as Ensifer moralensis H16. The strain completely utilizes perfluorooctane sulfonate in a liquid medium under the batch fermentation conditions for 120 hours. The strain biodegrades perfluorooctane sulfonate into perfluoroheptanoic acid with the release of four F-ions from one PFOS molecule into the medium (final PFOS concentration is 152 mg/L; initial PFOS concentration in the medium is 1,000 mg/L). In this study 88% of PFOS was decomposed by the new strain after treating contaminated soil in a model experiment. The isolated strain Ensifer moralensis H16 can be used in development of biological products for the utilization of environmental pollution caused by organofluorine compounds. [ABSTRACT FROM AUTHOR]

Aim: Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are persistent pollutants associated with adverse birth outcomes. This study aimed to identify predictors of blood PFOA and PFOS concentrations in pregnant women and to estimate their associations with birth outcomes in Brazil. Methods: We conducted a cross‐sectional study with 139 pregnant women enrolled in the pilot study of the Rio Birth Cohort Study on Environmental Exposure and Childhood Development (PIPA Project). Multiple linear regression was used to estimate associations between PFOA and PFOS with maternal predictors and birth outcomes. Results: Higher levels of PFOA were observed in women aged 16–19 and 20–39 years, while fish consumption from 0.6 to 2.0 times per week was associated with lower levels of the substance. PFOS levels were higher in women living in houses with up to four rooms but lower in those who reported passive exposure to smoking. Increased newborn length and head circumference were also associated with higher maternal levels of PFOA. Conclusions: In our study, age, fish consumption, passive smoking, and the number of rooms in the house were predictors of maternal PFAS levels. However, we did not observe significant associations between maternal plasma PFAS concentrations and birth outcomes. [ABSTRACT FROM AUTHOR]

Background: Per- and polyfluoroalkyl substances (PFAS) are highly persistent chemicals that have been detected in the serum of over 98% of the US population. Studies among highly exposed individuals suggest an association with perfluorooctanoic acid (PFOA) exposure and kidney cancer. It remains unclear whether PFOA or other PFAS are renal carcinogens or if they influence risk of renal cell carcinoma (RCC) at concentrations observed in the general population.Methods: We measured prediagnostic serum concentrations of PFOA and 7 additional PFAS in 324 RCC cases and 324 individually matched controls within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Multivariable conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CIs) relating serum PFAS concentrations and RCC risk. Individual PFAS were modeled continuously (log2-transformed) and categorically, with adjustment for kidney function and additional potential confounders. All statistical tests were 2-sided.Results: We observed a positive association with RCC risk for PFOA (doubling in serum concentration, ORcontinuous = 1.71, 95% CI = 1.23 to 2.37, P = .002) and a greater than twofold increased risk among those in the highest quartile vs the lowest (OR = 2.63, 95% CI = 1.33 to 5.20, Ptrend = .007). The association with PFOA was similar after adjustment for other PFAS (ORcontinuous = 1.68, 95% CI = 1.07 to 2.63, P = .02) and remained apparent in analyses restricted to individuals without evidence of diminished kidney function and in cases diagnosed 8 or more years after phlebotomy.Conclusions: Our findings add substantially to the weight of evidence that PFOA is a renal carcinogen and may have important public health implications for the many individuals exposed to this ubiquitous and highly persistent chemical. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFAS) are surface‐active agents used in diverse industrial and commercial applications. They contaminate both freshwater and marine ecosystems, are highly persistent, and accumulate through trophic transfer. Seabirds are exposed to environmental contaminants due to their high trophic position in food webs and relatively long lifespan. We measured levels of 10 perfluoroalkyl acids (PFAAs) in egg yolks of yellow‐legged gulls (Larus michahellis) breeding in the northern Adriatic Sea (Northeast Italy). We examined variations in PFAAs within clutches (between eggs of different laying order) and among clutches. Perfluorooctane sulfonate (PFOS) was the most abundant yolk PFAA (mean = 42.0 ng/g wet wt), followed by perfluorooctanoic acid (PFOA; 3.8 ng/g wet wt) and perfluorododecanoic acid (PFDoDa; 2.8 ng/g wet wt). The ∑PFAAs averaged 57.4 ng/g wet weight, ranging between 26.5 and 115.0 ng/g wet weight. The PFAA levels varied substantially among clutches (0.29–0.79 of the total variation), whereas the effects of laying order were considerably weaker (0.01–0.13). Egg‐laying order effects were detected for ∑PFAAs, PFOS, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and PFDoDa, whereby the last‐laid eggs exhibited lower PFAA concentrations than early‐laid eggs. Our results indicate that seagulls from the northern Adriatic basin deposit measurable amounts of PFAAs in their eggs. The large among‐clutches differences in PFAAs suggest that exposure of yellow‐legged gull females to these compounds is highly variable. Environ Toxicol Chem 2021;40:744–753. © 2020 SETAC [ABSTRACT FROM AUTHOR]

Perfluoroalkyl acids (PFAAs) are persistent environmental contaminants that are associated with various adverse health outcomes. Perfluorooctanoic acid (PFOA) is one of the most prominently detected PFAAs in the environment, which is now replaced with shorter chain carbon compounds including perfluorohexanoic acid (PFHxA) and perfluorobutyric acid (PFBA). The aim of this study was to compare the toxicity of four PFAAs as a function of chain length and head group (carboxylate versus sulfonate) with in vitro and in vivo zebrafish assessments, which were subsequently compared to other cell and aquatic models. Mortality rate increased with chain length (PFOA > PFHxA ≫ PFBA) in both whole embryo/larvae and embryonic cell models. The sulfonate group enhanced toxicity with perfluorobutane sulfonate (PFBS) showing higher toxicity than PFBA and PFHxA in both larvae and cells. Toxicity trends were similar among different aquatic models, but sensitivities varied. Discrepancies with other zebrafish studies were confirmed to be associated with a lack of neutralization of acidic pH of dosing solutions in these other investigations, demonstrating the need for rigor in reporting pH of exposure solutions in all experiments. The zebrafish embryonic cell line was also found to be similar to most other cell lines regardless of exposure length. Overall, results agree with findings in other cell lines and organisms where longer chain length and sulfonate group increase toxicity, except in investigations not neutralizing the exposure solutions for these acidic compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • SSC influences the microscopic morphology of BiOCl. • Thin-sheet like structure enhances the absorption of light. • Level of OVs has been promoted. • Photogenerated charge pairs separation efficiency has been boosted. In this work, a one-pot hydrothermal method was employed to fabricate sorghum straw carbon (SSC) modified BiOCl catalysts. SSC not only operates as a template agent to regulate the microscopic morphology of BiOCl to form thinner lamellar structures but also constructs oxygen vacancies (OVs), which together enhance the photocatalytic ability. The samples were researched by Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD) and scanning electron microscope (SEM). Addition of SSC induce BiOCl to form a flower spherical-like structure assembled by thin sheets. Surface photovoltage spectroscopy (SPS) and electrochemical experiments confirm that the dense interlayer stacking provides more pathways for the separation of charges from bulk to the surface, and the thinner sheet thickness shortens the separation time for the charges, boosting the activity of the photocatalysts. The existence of the main reactive radicals (O 2 – and h+) in the photocatalytic system was investigated by trapping experiments. Photocatalytic activity of the samples was assessed by destruction of rhodamine B (RhB), tetracycline (TC) and perfluorooctanoic acid (PFOA). When the mass ratio of SSC/BiOCl is 0.75%, the catalyst shows the best photocatalytic activity. A reasonable photocatalytic enhancement mechanism was proposed in combination with the observation results. [ABSTRACT FROM AUTHOR]

Landfill leachates are complex mixtures containing very high concentrations of biodegradable and recalcitrant toxic compounds. Understanding the major contaminant components and microbial community signatures in global landfill leachates is crucial for timely decision-making regarding contaminant management and treatment. Therefore, this study analyzed leachate data from 318 landfill sites primarily used for municipal solid waste disposal, focusing on their chemical and microbiological characteristics. The most prevalent and dominant components in landfill leachates are the chemical oxygen demand (COD, 3.7–75.9 × 103 mg/L) and NH 4 + (0.03–0.81 × 104 mg/L), followed by salt species such as SO 4 2- (0.03–5.25 × 103 mg/L), Cl- (3.2–7.8 × 103 mg/L), K+ (0.58–4.20 × 103 mg/L), Na+ (1.3–13.0 × 103 mg/L) and Ca2+ (2.35–230.23 × 103 mg/L), which exhibit significant fluctuations. Heavy metals and metalloids are widely distributed in most landfill leachates but at relatively low concentrations (<182.8 mg/L) compared to conventional parameters. Importantly, there is a distinct global variation in the occurrence of emerging environmental contaminants (ECs). Among these compounds, perfluorooctanoic acid (PFOA, 0.02–7.50 × 103 μg/L) of per- and poly-fluoroalkyl substances (PFAS), bisphenol A (BPA, 0.01–33.46 × 103 μg/L) belonged to endocrine-disrupting compounds (EDCs), together with di-ethyltoluamide (DEET, 1.0–1.0 × 103 μg/L) affiliated to pharmaceuticals and personal care products (PPCPs) are the most frequently detected in landfill leachates. Additionally, the microbial community compositions in most leachates are primarily dominated by Proteobacteria, Bacteroidota, Firmicutes, and Chloroflexi, and some of their abundances are correlated with the concentrations of NH 4 +, NO 3 -, Cl-, Na+ and Cr. Notably, the leading microbes driving advanced removal of inorganic nitrogen in the treatment systems are Candidatus Brocadia (anammox), denitrifying Thauera , nitrite-oxidizing bacteria Nitrospira , along with ammonia-oxidizing bacteria Nitrosomonas and Nitrosospira. The findings of this work provide a deeper insight into the leachate characteristics and the sustainable management of landfill leachates, especially presenting a snapshot of the global distribution of pollutants and also the microbiome. [Display omitted] • Large regional variations are detected among 318 landfill leachates globally. • Heavy metals and new emerging contaminants are prevalent in leachates. • Major microbes driving nitrogen turnover are identified in leachate treatment. • Correlation exists between specific microorganisms and leachate parameters. • Leachate parameters are determinants for the specific microbes. [ABSTRACT FROM AUTHOR]

[Display omitted] • The two-component oxidant system persulfate + MnO 2 is active at low temperatures. • MnO 2 is a primary oxidant rather than a catalyst. • Persulfate acts as a secondary oxidant which re-oxidizes MnO x. • The advantage of MnO 2 over direct persulfate oxidation is highest at low temperatures. • Singlet oxygen 1O 2 does not play a major role in the oxidation process. MnO 2 can be used in advanced oxidation processes to activate peroxydisulfate (PS) and generate reactive species such as sulfate radicals (SO 4 •-), hydroxyl radicals (•OH) and singlet oxygen (1O 2) for the abatement of organic water contaminants. Alternatively, one can use MnO 2 as particulate oxidant which, in contrast to PS, is active already at low temperatures. This low-temperature activity is particularly attractive for in situ groundwater treatment. The roles of PS and MnO 2 as oxidant and catalyst, respectively, may invert: MnO 2 functions as primary oxidant and PS works as re-oxidant of reduced Mn-oxides. In this way, the limited oxidation capacity of particulate MnO 2 can be overcome. So far, such reaction systems have not been extensively explored. In the present study, the degradation of 4-hydroxybenzoic acid (HBA) by PS + MnO 2 was studied under various experimental conditions, by varying reaction temperature (15–45 °C), reagent concentrations, and water matrix. Both PS and MnO 2 alone have the ability to effect the oxidation of HBA. In the co-presence of PS and MnO 2 , a fast removal of HBA from water was achieved even at low temperatures (half-life of HBA about 0.5 h with 2.4 g L-1 MnO 2 at 25 °C), owing to a synergic effect between the two components. Quenching experiments indicate that the primary HBA oxidation step is a heterogeneous reaction on the MnO 2 surface rather than a homogeneous reaction driven by SO 4 •- or 1O 2 , as frequently reported in literature. This is in line with results from the PS driven oxidation of perfluorooctanoic acid which is not significantly enhanced in the presence of MnO 2. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large category of crucial environmental contaminants of global concerns. There are limited data on PFAS in surface water around international airports in China. The present study investigated the concentrations, distributions, and sources of emerging and legacy PFAS in surface waters around Beijing Capital International Airport (BC), Shanghai Pudong International Airport (SP), and Guangzhou Baiyun International Airport (GB) in China. Twenty-seven target compounds were quantified. The Σ 27 PFAS concentrations ranged from 19.0 to 62.8 ng/L (mean 36.1 ng/L) in BC, 25.6–342 ng/L (mean 76.0 ng/L) in SP, 7.35–72.7 ng/L (mean 21.6 ng/L) in GB. The dominant compound was perfluorooctanoic acid (PFOA), which accounted for an average of 27% (5%–65%) of the Σ 27 PFAS concentrations. The alternatives with –C 6 F 12 - group had detection frequencies ranging from 72% to 100%. The partition coefficient results indicate that the longer chain PFAS (C > 8) tend to be more distributed in the particle phase. Fifty suspect and nontarget PFAS were identified. In GB, 44 PFAS were identified, more than SP of 39 and BC of 38. An ultra short-chain (C = 2) precursor, N-methylperfluoroethanesulfonamido acetic acid (MeFEtSAA), was identified and semi-quantified. Domestic wastewater discharges might be the main sources around BC, while industrial and aviation activities might be the main sources around SP and GB. [Display omitted] • C ≤ 8 PFAS were widespread in the environment around airports. • PFOA was the dominant compound. • The alternatives with –C 6 F 12 - group had detection frequencies ranging from 72% to 100%. • The ultra short-chain precursor MeFEtSAA (C = 2) was identified and semi-quantified. • The sources of PFAS in the surface water around the three airports were different. [ABSTRACT FROM AUTHOR]

[Display omitted] • BiOCl with riched oxygen vacancies was prepared. • The level of ·O 2 – is significantly increased. • The separation efficiency of photoinduced charge pairs has been enhanced. • Rich oxygen vacancies facilitate photocatalytic performance of BiOCl. In this demonstration, SiO 2 /BiOCl composites were fabricated by loading SiO 2 nanoparticles onto the surface of BiOCl nanosheets through a conventional hydrothermal approach. SiO 2 /BiOCl photocatalysts were studied by specific surface area analysis, X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV–Vis diffuse reflection spectroscopy (UV–Vis DRS) and electron spin resonance (ESR) techniques. In light of the rich pore structures of BiOCl modified by SiO 2 , the photogenerated carriers separation efficiency of SiO 2 /BiOCl is significantly improved. Therefore, SiO 2 /BiOCl composite nanosheets show high efficiency towards degradation of perfluorooctanoic acid (PFOA) and rhodamine B (RhB), and the composites display exceptional stability. In comparison to the pure BiOCl, photocatalytic degradation activity of 4.4 % SiO 2 /BiOCl (mass ratio of SiO 2 /Bi(NO 3) 3 ·5H 2 O is 4.4 %) for RhB and PFOA increases by 100 % and 50 %, respectively. The result from the radical capture experiments suggests that holes (h+) and superoxide radicals (·O 2 –) play a crucial role as the primary active species in degradation of organic pollutants. The enhanced photocatalytic efficiency of the SiO 2 /BiOCl composites can be primarily ascribed to the construction of numerous oxygen vacancies (OVs), which effectively promote the adsorption of organic pollutants, boost light responsiveness, and expedite the separation of photoinduced e-/h+ pairs. [ABSTRACT FROM AUTHOR]

• A novel electrified membrane was fabricated to remove and degrade organic pollutants. • Sequential anodic oxidation and cathodic electro-Fenton was created in a Janus membrane. • Organic pollutants were first directly oxidized on the Ti 4 O 7 anode. • The cathodic ·OH further enhanced the mineralization of organic pollutants. • The reagent-free electrified membrane is competitive and universal in pollutant removal. Electrified membrane technologies have recently demonstrated high potential in tackling water pollution, yet their practical applications are challenged by relying on large precursor doses. Here, we developed a Janus porous membrane (JPEM) with synergic direct oxidation by Magnéli phase Ti 4 O 7 anode and electro-Fenton reactions by CuFe 2 O 4 cathode. Organic pollutants were first directly oxidized on the Ti 4 O 7 anode, where the extracted electrons from pollutants were transported to the cathode for electro-Fenton production of hydroxyl radical (·OH). The cathodic ·OH further enhanced the mineralization of organic pollutant degradation intermediates. With the sequential anodic and cathodic oxidation processes, the reagent-free JPEM showed competitive performance in rapid degradation (removal rate of 0.417 mg L−1 s−1) and mineralization (68.7 % decrease in TOC) of sulfamethoxazole. The JPEM system displayed general performance to remove phenol, carbamazepine, and perfluorooctanoic acid. The JPEM runs solely on electricity and oxygen that is comparable to that of PEM relies on large precursor doses and, therefore, operation friendly and environmental sustainability. The high pollutant removal and mineralization achieved by rational design of the reaction processes sheds light on a new approach for constructing an efficient electrified membrane. [Display omitted] [ABSTRACT FROM AUTHOR]

Molecular design of redox‐materials provides a promising technique for tuning physicochemical properties which are critical for selective separations and environmental remediation. Here, the structural tuning of redox‐copolymers, 4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TMA) and 4‐methacryloyloxy‐2,2,6,6‐tetramethylpiperidine (TMPMA), denoted as P(TMAx‐co‐TMPMA1−x), is investigated for the selective separation of anion contaminants ranging from perfluorinated substances to halogenated aromatic compounds. The amine functional groups provide high affinity toward anionic functionalities, while the redox‐active nitroxyl radical groups promote electrochemically‐controlled capture and release. Controlling the ratio of amines to nitroxyl radicals provides a pathway for tuning the redox‐activity, hydrophobicity, and binding affinity of the copolymer, to synergistically enhance adsorption and regeneration. P(TMAx‐co‐TMPMA1−x) removes a model perfluorinated compound (perfluorooctanoic acid (PFOA)) with a high uptake capacity (>1000 mg g−1) and separation factors (500 vs chloride), and demonstrates exceptional removal efficiencies in diverse per‐ and polyfluoroalkyl substances (PFAS) and halogenated aromatic compounds, in various water matrices. Integration with a boron‐doped diamond electrode allows for tandem separation and destruction of pollutants within the same electrochemical cell, enabling the energy integration of the separation step with the catalytic degradation step. The study demonstrates for the first time the tuning of redox‐copolymers for selective remediation of organic anions, and integration with an advanced electrochemical oxidation process for energy‐efficient water purification. [ABSTRACT FROM AUTHOR]

The development of effective remedial technologies for the destruction of environmental pollutants requires the ability to clearly monitor degradation processes. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for understanding reaction progress; however, practical considerations often restrict the application of NMR spectroscopy as a tool to better understand the degradation of environmental pollutants. Chief among these restrictions is the limited access smaller environmental research labs and remediation companies have to suitable NMR facilities. Benchtop NMR spectroscopy is a low‐cost and user‐friendly approach to acquire much of the same information as conventional nuclear magnetic resonance (NMR) spectroscopy, albeit with reduced sensitivity and resolution. This paper explores the practical application of benchtop NMR spectroscopy to understand the degradation of perfluorooctanoic acid using sodium persulfate, a common reagent for the destruction of groundwater contaminants. It is found that Benchtop 19F NMR spectroscopy is able to monitor the complete degradation of perfluorooctanoic acid into fluoride; however, the observation of intermediate degradation products formed, which can be observed using a conventional NMR spectrometer, cannot be readily distinguished from the parent compound when measurements are performed using the benchtop instrument. Under certain reaction conditions, the formation of fluorinated structures that are resistant to further degradation is readily observed. Overall, it is shown that benchtop 19F NMR spectroscopy has potential as a quick and reliable tool to assist in the development of remedial technologies for the degradation of fluorinated contaminants. [ABSTRACT FROM AUTHOR]

• UV single treatment could not degrade HFPO-TA efficiently. • Reductive active species played dominant roles in HFPO-TA photodegradation. • HFPO-TA transformed to HFPO-DA, then PFA and TFA in degradation pathway. • Acidic condition promoted HFPO-TA photodegradation under anaerobic condition. • High concentration of humic acid restrained HFPO-TA photodegradation. As a novel alternative to traditional perfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), hexafluoroproplyene oxide trimer acid (HFPO-TA) has been detected worldwide in surface water. Moreover, recent researches have demonstrated that HFPO-TA has stronger bioaccumulation potential and higher hepatotoxicity than PFOA. To treat these contaminants e.g. PFOA and PFOS, some photochemical techniques by adding exogenous substances had been reported. However, there is still no report for the behavior of HFPO-TA itself under direct UV irradiation. The current study investigated the photo-transformation of HFPO-TA under UV irradiation in aqueous solution. After 72 hr photoreaction, 75% degradation ratio and 25% defluorination ratio were achieved under ambient condition. Reducing active species, i.e., hydrated electrons and active hydrogen atoms, generated from water splitting played dominant roles in degradation of HFPO-TA, which was confirmed by different effects of reaction atmospheres and quenching experiments. A possible degradation pathway was proposed based on the products identification and theoretical calculations. In general, HFPO-TA would be transformed into shorter-chain PFASs, including hexafluoropropylene oxide dimer acid (HFPO-DA), perfluoropropionic acid (PFA) and trifluoroacetate (TFA). This research provides basic information for HFPO-TA photodegradation process and is essential to develop novel remediation techniques for HFPO-TA and other alternatives with similar structures. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Removals were 59–68% of PFOA and 66–96% of PFOS, depending on the concentrations. • Adsorption on the sludge was the main responsible of the removal, particularly for PFOS. • Loss from the system was observed, due to processes other than biological and adsorption. • The inhibition index was found equal to 14 % at 4000 ng/L concentrations. • Adsorbed pollutants were released from the sludge for less than 1 %. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the most investigated compounds in the class of perfluoroalkyl substances for their persistence and wider diffusion in the environment. However, fate and behaviour of PFOA and PFOS in the Wastewater Treatment Plants (WWTPs) have not been fully understood yet. The aim of the present study was to obtain a better understanding of the processes occurring to PFOS and PFOA in the activated sludge reactor. Several experimental tests were performed in the presence of activated sludge and sterilized sludge. PFOA and PFOS showed removals from the liquid phase from 59 % to 68 % and from 66 % to 96 %, respectively, for initial concentrations from 200 ng/L to 4000 ng/L in the presence of activated sludge. A significant fraction of the initial contaminant load was found adsorbed on the sludge, mainly in the case of PFOS. Other processes occurred, not fully identified, which were responsible of a further loss from the system. Leaching tests showed negligible release of the adsorbed pollutants from the sludge. Carbon and ammonia removal in the activated sludge reactor were not significantly affected by the presence of PFOA and PFOS. The pseudo-second order kinetic model and the Freundlich isotherm provided the best fitting of the experimental data. [ABSTRACT FROM AUTHOR]

Background: Perfluoroalkyl substances (PFASs) are persistent organic pollutants that are suspected to be neurodevelopmental toxicants, but epidemiological evidence on neurodevelopmental effects of PFAS exposure is inconsistent. We investigated the associations between prenatal exposure to PFASs and symptoms of attention-deficit/hyperactivity disorder (ADHD) and cognitive functioning (language skills, estimated IQ and working memory) in preschool children, as well as effect modification by child sex.Material and Methods: This study included 944 mother-child pairs enrolled in a longitudinal prospective study of ADHD symptoms (the ADHD Study), with participants recruited from The Norwegian Mother, Father and Child Cohort Study (MoBa). Boys and girls aged three and a half years, participated in extensive clinical assessments using well-validated tools; The Preschool Age Psychiatric Assessment interview, Child Development Inventory and Stanford-Binet (5th revision). Prenatal levels of 19 PFASs were measured in maternal blood at week 17 of gestation. Multivariable adjusted regression models were used to examine exposure-outcome associations with two principal components extracted from the seven detected PFASs. Based on these results, we performed regression analyses of individual PFASs categorized into quintiles.Results: PFAS component 1 was mainly explained by perfluoroheptane sulfonate (PFHpS), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA). PFAS component 2 was mainly explained by perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorononanoic acid (PFNA). Regression models showed a negative association between PFAS component 1 and nonverbal working memory [β = -0.08 (CI: -0.12, -0.03)] and a positive association between PFAS component 2 and verbal working memory [β = 0.07 (CI: 0.01, 0.12)]. There were no associations with ADHD symptoms, language skills or IQ. For verbal working memory and PFAS component 2, we found evidence for effect modification by child sex, with associations only for boys. The results of quintile models with individual PFASs, showed the same pattern for working memory as the results in the component regression analyses. There were negative associations between nonverbal working memory and quintiles of PFOA, PFNA, PFHxS, PFHpS and PFOS and positive associations between verbal working memory and quintiles of PFOA, PFNA, PFDA and PFUnDA, with significant relationships mainly in the highest concentration groups.Conclusions: Based on our results, we did not find consistent evidence to conclude that prenatal exposure to PFASs are associated with ADHD symptoms or cognitive dysfunctions in preschool children aged three and a half years, which is in line with the majority of studies in this area. Our results showed some associations between PFASs and working memory, particularly negative relationships with nonverbal working memory, but also positive relationships with verbal working memory. The relationships were weak, as well as both positive and negative, which suggest no clear association - and need for replication. [ABSTRACT FROM AUTHOR]

In order to characterize exposure of the Canadian population to environmental chemicals, a human biomonitoring component has been included in the Canadian Health Measures Survey (CHMS). This nationally-representative survey, launched in 2007 by the Government of Canada, has measured over 250 chemicals in approximately 30,000 Canadians during the last decade. The capacity to interpret these data at the population level in a health risk context is gradually improving with the development of biomonitoring screening values, such as biomonitoring equivalents (BE) and human biomonitoring (HBM) values. This study evaluates recent population level biomonitoring data from the CHMS in a health risk context using biomonitoring screening values. Nationally representative biomonitoring data for fluoride, selenium, molybdenum, arsenic, silver, thallium, cyfluthrin, 2,4-dichlorophenoxyacetic acid (2,4-D), 3-phenoxybenzoic acid (3-PBA), chlorpyrifos, deltamethrin, bisphenol A, triclosan, acrylamide, cadmium, perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), bromoform, chloroform, benzene, toluene, xylene, ethylbenzene, styrene and tetrachloroethylene were screened as part as this study. For non-cancer endpoints, hazard quotients (HQs) were calculated as the ratio of population level concentrations of a specific chemical at the geometric mean and 95th percentile to the corresponding biomonitoring screening value. Cancer risks were calculated at the 5th, 25th, 50th, 75th and 95th percentiles of the population concentration using BEs based on a risk specific dose. Most of the chemicals analyzed had HQs below 1 suggesting that levels of exposure to these chemicals are not a concern at the population level. However, HQs exceeded 1 in smokers for cadmium, acrylamide and benzene, as well as in the general population for inorganic arsenic, PFOS and PFOA, 3-PBA and fluoride. Furthermore, cancer risks for inorganic arsenic, acrylamide, and benzene at most population percentiles of exposure were elevated (>10−5). Specifically, for inorganic arsenic in the general population, the HQ was 3.13 at the 95th percentile concentration and the cancer risk was 3.4 × 10−4 at the 50th percentile of population concentrations. These results suggest that the levels of exposure in the Canadian population to some of the environmental chemicals assessed might be of concern. The results of this screening exercise support the findings of previous risk assessments and ongoing efforts to reduce risks from exposure to chemicals evaluated as part of this study. Although paucity of biomonitoring screening values for several environmental contaminants may be a limitation to this approach, our assessment contributes to the prioritization of a number of chemicals measured as part of CHMS for follow-up activities such as more detailed characterization of exposure sources. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFASs) have become an important class of global environmental contaminants, yet their vertical profile in the marine water column is still less understood, especially for the semi-closed seas. In this study, the contamination level and spatial distribution of 8 PFASs were investigated in both surface and vertical water samples from two semi-closed seas, the Japan Sea and the Mediterranean Sea. Similar levels and compositions of PFASs were found between these two seas. The vertical profile of PFASs in the Mediterranean Sea was variable while that was relatively steady in the Japan Sea, probably due to their different pollution sources. The accumulation rate of PFASs from the East China Sea to the Japan Sea was calculated, for which perfluorooctanesulfonic acid and perfluorooctanoic acid were found to have high accumulation potency in both surface and deep water; most of the investigated PFASs were accumulated in the deep water due to the long residence time while they were more likely to escape to the Pacific Ocean in the surface water. This work aimed (i) to study the distribution of PFASs in both surface and vertical water samples in two semi-closed seas, namely the Japan Sea and for the first time the Mediterranean Sea, (ii) to assess the temporal trend in the Japan Sea, and (iii) to firstly investigate the potential transport of PFASs from the East China Sea and Taiwan Strait in order to estimate the inventory of PFASs in whole water mass in the Japan Sea. Image 1 • A remarkable increase in PFASs levels was found in the Japan Sea from 2005 to 2010. • The inventory of PFASs in whole water mass was firstly assessed in semi-closed sea. • The annual ΣPFASs inflow from the East China Sea to the Japan Sea was around 70.8 t. • The PFASs vertical profile in the Mediterranean Sea implied a few pollution sources. • PFOA predominated in the Japan Sea, the Mediterranean Sea, and the East China Sea. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances are synthetic environmental pollutants previously used for packaging applications as a grease, oil, and water-resistant coating. Exposure reported in previous studies highlighting potential concerns with public health. This study evaluated performance of coated paper packaging used for microwave popcorn, snacks, and sandwich bags for presence of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Current paper packaging materials: seven popcorn bags and three snack and sandwich bags were analysed for PFOA and PFOS and compared to concentrations in microwave popcorn bags between 2005 and 2018. Only two microwave popcorn bags had average PFOA content above the limit of quantitation of 5.11 ng g−1 paper. All other sample types had PFOA and PFOS values below the limit of detection (LOD) of 1.53 and 0.63 ng g−1 paper, respectively. Results of this study follow trends from 2005 to 2018 suggesting a reduction in PFOS and PFOA concentrations in microwave packaging. [ABSTRACT FROM AUTHOR]

Summary: Organic pollutants (OPs) are critically toxic, bioaccumulative and globally widespread. Moreover, several OPs negatively influence aquatic wildlife. Although bacteria are major drivers of the ocean carbon cycle and the turnover of vital elements, there is limited knowledge of OP effects on heterotrophic bacterioplankton. We therefore investigated growth and gene expression responses of the Baltic Sea model bacterium Rheinheimera sp. BAL341 to environmentally relevant concentrations of distinct classes of OPs in 2‐h incubation experiments. During exponential growth, exposure to a mix of polycyclic aromatic hydrocarbons, alkanes and organophosphate esters (denoted MIX) resulted in a significant decrease (between 9% and 18%) in bacterial abundance and production compared with controls. In contrast, combined exposure to perfluorooctanesulfonic acids and perfluorooctanoic acids (denoted PFAS) had no significant effect on growth. Nevertheless, MIX and PFAS exposures both induced significant shifts in gene expression profiles compared with controls in exponential growth. This involved several functional metabolism categories (e.g. stress response and fatty acids metabolism), some of which were pollutant‐specific (e.g. phosphate acquisition and alkane‐1 monooxygenase genes). In stationary phase, only two genes in the MIX treatment were significantly differentially expressed. The substantial direct influence of OPs on metabolism during bacterial growth suggests that widespread OPs could severely alter biogeochemical processes governed by bacterioplankton. [ABSTRACT FROM AUTHOR]

• UiO-66 and UiO-67 MOFs have been used for the extraction of pollutants from aqueous solution. • Both materials present a high sorption capacity to remove the pollutants. • Sorption isotherms were obtained and revealed different mechanisms of sorption depending of the cavity size. Zirconium Metal-organic frameworks (MOFs, UiO-66 and UiO-67) have been used for the removal from aqueous solutions of persistent fluorinated pollutants, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). The two isostructural materials differ in cavity size, defined by the ligand, bdc (benzene-dicarboxylic acid) or bpdc (biphenyl-dicarboxylic acid) for UiO-66 and UiO-67 respectively. Both materials enable efficient sorption of PFOA and PFOS. Sorption kinetics and isotherms have been experimentally determined, and thermodynamic parameters ΔH°, ΔS° and ΔG° have been determined. UiO-67 shows higher sorption capacities (up to 743 mg·g−1 for PFOA and 585 mg·g−1 for PFOS) compared to these of UiO-66 (388 and 160 mg·g−1 for the sorption of PFOA and PFOS respectively) with a change in the sorption mechanism. [ABSTRACT FROM AUTHOR]

Hazardous chemicals, such as perfluoroalkyl substances (PFASs) and antibiotics, coexist in aquatic environments and pose a severe threat to aquatic organisms. However, research into the toxicity of these pollutants on submerged macrophytes and their periphyton is still limited. To assess their combined toxicity, Vallisneria natans (V. natans) was exposed to perfluorooctanoic acid (PFOA) and sulfadiazine (SD) at environmental concentrations. Photosynthetic parameters such as chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids were lower in the SD exposure group, indicating that SD had a significant effect on the photosynthesis of aquatic plants. Single and combined exposures effectively induced antioxidant responses, with increases in superoxide dismutase, peroxidase activities, and ribulose-1,5-bisphosphate carboxylase concentrations, as well as malondialdehyde content. Accordingly, antagonistic toxicity was assessed between PFOA and SD. Furthermore, metabolomics revealed that V. natans improved stress tolerance through changes in enoic acid, palmitic acid, and palmitoleoyloxymyristic acid related to the fatty acid metabolism pathway responding to the coexisting pollutants. Additionally, PFOA and SD in combination induced more effects on the microbial community of biofilm. The alternation of α- and β- D -glucopyranose polysaccharides and the increased content of autoinducer peptides and N -acylated homoserine lactones indicated that PFOA and SD changed the structure and function of biofilm. These investigations provide a broader perspective and comprehensive analysis of the responses of aquatic plants and periphyton biofilms to PFAS and antibiotics in the environment. [Display omitted] • Antagonistic toxicity was assessed between PFOA and SD. • V. natans improved stress tolerance through the fatty acid metabolism pathway. • AHL was the dominant signaling molecules changed in biofilms. [ABSTRACT FROM AUTHOR]

[Display omitted] Per- and polyfluoroalkyl substances (PFAS) are persistent and ubiquitous environmental contaminants with well-documented hepatotoxicity. However, the mechanistic linkage between PFAS exposure and non-alcoholic fatty liver disease (NAFLD) remains largely elusive. This study aimed to explore PFAS-to-NAFLD link and the relevant molecular mechanisms. The cross-sectional analyses using National Health and Nutrition Examination Survey (NHANES) data were conducted to investigate the association between PFAS exposure and NAFLD. A combination of in silico toxicological analyses, bioinformatics approaches, animal experiments, and in vitro assays was used to explore the molecular initiating events (MIEs) and key events (KEs) in PFAS-induced hepatic lipid metabolism disorders. The cross-sectional analyses with NHANES data revealed the significant association between PFAS exposure and hepatic steatosis/NAFLD. The in silico toxicological analyses showed that PPARα activation induced by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), prototypical representatives of PFAS, is the critical MIE associated with NAFLD-predominant liver diseases. Transcriptome-based bioinformatic annotation and analyses identified that transcriptional upregulation of hepatic acyl-CoA oxidase 1 (ACOX1) in PPARα-regulated peroxisomal β-oxidation pathway was the KE involved with PFOA/PFOS-perturbed hepatic lipid metabolic pathways in humans, mice and rats. The in vivo and in vitro assays further verified that ACOX1-mediated oxidative stress contributed to mitochondrial compromise and lipid accumulation in PFOA/PFOS-exposed mouse hepatocytes, which could be mitigated by co-treatment with ACOX1 inhibitor and mitochondria ROS scavenger. Additionally, we observed that besides PFOA and PFOS, hepatic ACOX1 exhibited good-fit response to short-term exposures of long-chain (C7-C10) perfluoroalkyl carboxylic acids (PFHpA, PFNA, PFDA) and perfluoroalkyl sulfonic acids (PFHpS, PFDS) in human hepatocyte spheroids through benchmark dose (BMD) modeling. Our study unveils a novel molecular target for PFAS-induced hepatic lipid metabolic disorders, shedding new light on prediction, assessment, and mitigation of PFAS hepatotoxicity. [ABSTRACT FROM AUTHOR]

Abstract Measurement and reporting of concentrations of contaminants of emerging concern such as per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA), is an integral part of most investigations. Occurrence of sorption losses of PFAS analytes onto particular laboratory-ware (e.g. glass containers) has been suggested in the published literature but has not been investigated in detail. We examined sorption losses from aqueous PFOA solutions in contact with different commonly-used materials in filter units and centrifuge tubes (glass and plastics). Sorption of PFOA onto different filter membrane types ranged from 21–79% indicating that filtration can introduce a major source of error in PFOA analysis; pre-treatment of filter membranes with phosphate or methanol solutions did not improve PFOA recovery. Substantial adsorption of PFOA was also observed on tubes made from polypropylene (PP), polystyrene (PS), polycarbonate (PC), and glass where losses observed were between 32–45%, 27–35%, 16–31% and 14–24%, respectively. Contrary to suggestions in the literature, our results indicated that the greatest sorption losses for PFOA occurred on PP, whereas losses on glass tubes were much lower. Variations in ionic strength and pH did not greatly influence PFOA recovery. When PFOA concentrations were increased, the percent recovery of PFOA increased, indicating that binding sites on tube-walls were saturable. This study draws attention towards analytical bias that can occur due to sorption losses during routine procedures, and highlights the importance of testing the suitability of chosen laboratory-ware for specific PFAS analytes of interest prior to experimental use. Highlights • Sorption of PFOA onto lab-ware can cause analytical bias during routine procedures. • Filtration of PFOA solutions can lead to underestimation of dissolved concentrations. • Sorption losses of PFOA onto polypropylene tubes was greater than on glass tubes. • Sorption losses decreased when concentrations of PFOA in test solutions increased. [ABSTRACT FROM AUTHOR]