Perfluorooctane Sulfonate Concentrations Research Articles

Electrochemical destruction and mobilization of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in saturated soil

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have attracted attention due to their widespread distribution, recalcitrance, and substantial toxicity. In this work, high concentrations of PFOA and PFOS were degraded and mobilized through electrochemical treatments in a simulated source zone of saturated soil. Under a low constant voltage and direct current of 24 V and 467–690 mA, approximately 51.7% and 33% of PFOA and PFOS were degraded, respectively. Additionally, a total defluorination mass balance of 44.7% and 23% were detected for PFOA and PFOS, respectively, which indicates that the removal of PFOA and PFOS occurs through its destruction. Substantial electromigration causes the destruction and mobilization of solid PFOA and PFOS to shift into the water phase. Although electrochemical oxidation of PFAS (per- and polyfluoroalkyl substances) were previously reported and studied, this study is one of the few that focus on simultaneous desorption, mobilization, and destruction of PFAS in saturated soil containing a low-intensity electrical field.

Model-Based Assessment of Groundwater Contamination with PFOS due to Fire-Training Activities

Aqueous film-forming foams (AFFFs) containing perfluoro-octane sulfonate (PFOS) were commonly used in fire trainings until the awareness of their toxicity started to increase in the 2000s. Our objective was to build a modeling framework for estimating groundwater pollution with PFOS, utilizing dual-permeability modeling still novel for groundwater studies. The framework was applied to an existing contamination site. According to the results, only 27% of PFOS released from the fire-training area reached the aquifer. Adsorption to unburnt fuels and removal via oil separation wells before discharging to the aquifer can substantially reduce the PFOS contamination of groundwater. Despite this, the PFOS concentration in a groundwater intake area 1.9 km from the pollutant source was predicted to exceed the limits set for drinking water, in contrast to earlier predictions based solely on monitoring. The study demonstrates the importance of modeling for groundwater management as the data on AFFF usage and composition, and on soil and groundwater contamination with perfluorinated compounds and co-pollutants typically are limited in terms of the spatial and temporal scale of contamination.

Pregnancy per- and polyfluoroalkyl substances (PFAS) and hypertensive disorders of pregnancy in the Project Viva cohort

BACKGROUND AND AIM: Exposure to environmental chemicals may increase the risk of cardiovascular disease. However, data on associations between per- and polyfluoroalkyl substances (PFASs) and hypertensive disorders of pregnancy (HDP) are limited and inconsistent. We sought to determine the extent to which early-pregnancy PFAS concentrations are prospectively associated with HDP risk in a large cohort. METHODS: We studied 1,537 pregnant women from the Project Viva cohort in Boston, Massachusetts, USA. Using maternal plasma samples collected from 1999-2002 at a median of 9.7 gestational weeks, we quantified concentrations of eight PFAS [perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), perfluorononanoate (PFNA), 2-(N-ethyl-perfluorooctane sulfonamide) acetate (EtFOSAA), 2-(N-methyl-perfluorooctane sulfonamide) acetate (MeFOSAA), perfluorodecanoate (PFDeA), perfluorooctane sulfonamide (FOSA)]. PFDeA and FOSA were detected in 50% of samples and were not included in further analyses. We assessed HDP using clinical data and defined preeclampsia and gestational hypertension according to the National High Blood Pressure Education Program recommendations. We used multinomial logistic regression to estimate associations of log2-transformed continuous PFAS concentrations with categories of HDP [gestational hypertension, preeclampsia, normotensive (ref)], adjusting for age, race/ethnicity, education, smoking, marital status, and parity. RESULTS:A total of 56 (4%) of women developed preeclampsia and 106 (7%) developed gestational hypertension. We observed higher risk of gestational hypertension per doubling of concentrations of PFOS (odds ratio [OR] 1.28, 95% confidence interval [CI]: 0.96, 1.70), PFOA (OR 1.36, 95% CI: 0.99, 1.86), and PFHxS (OR 1.22, 95% CI: 1.01, 1.48). Associations with other PFAS were consistent in direction but smaller in magnitude (e.g., EtFOSAA: OR 1.14, 95% CI: 0.95, 1.38). We did not observe associations between PFAS concentrations and preeclampsia. CONCLUSIONS:Our results support the hypothesis that PFAS exposure during pregnancy may increase the risk of gestational hypertension. However, we did not observe associations between PFAS exposure and preeclampsia. KEYWORDS: PFAS, hypertensive disorders of pregnancy, gestational hypertension, preeclampsia, pregnancy

Sorption and desorption kinetics of PFOS to pristine microplastic

The sorption processes of persistent organic pollutants on microplastics particles are poorly understood. Therefore, the present study investigated the sorption processes of perfluorooctanesulfonate (PFOS) on polyethylene (PE) microplastic particles (MPs) which are representing a prominent environmental pollutant and one of the most abundant microplastic polymers in the aquatic environment, respectively. The focus was set on the investigation of the impact of the particle size on PFOS sorption using four different PE MPs size ranges. The sorption kinetics for 6 months was studied with one selected size range of PE MPs. Besides, the desorption of PFOS from PE MPs under simulated digestive conditions was carried out by using artificial gut fluid mimicking the intestinal juice of fish. The investigation of the size effects of particles over 6 months demonstrated a linear increase of PFOS concentration sorbed onto PE with a decrease of the particle size. Thus, our findings implicate efficient sorption of PFOS onto PE MPs of different sizes. The results showed that PFOS desorbed from the PE MPs into the artificial gut fluid with a rate of 70 to 80%. Besides, a longer exposure of PE MPs to PFOS leads to a higher concentration adsorbed by PE MPs, which may favor the ingestion of higher concentration of PFOS, and thus represents a higher risk to transfer relevant concentrations of PFOS during digestion.

Perfluorooctane Sulfonate in US Ambient Surface Waters: A Review of Occurrence in Aquatic Environments and Comparison to Global Concentrations

Perfluorooctane sulfonate (PFOS) is one of the dominant perfluoroalkyl substances (PFAS) detected in aquatic ecosystems. It has been used in a wide range of industrial and consumer products for decades. The unique properties of PFOS, including its stability and resistance to degradation, have made it highly persistent in the aquatic environment. Because of its persistence, potential toxicity, and occurrence in aquatic ecosystems, interest in PFOS has increased in recent decades. Despite this interest, current information on the environmental distribution of PFOS in ambient surface waters of the United States is fairly limited. This critical review summarizes the currently available literature on PFOS occurrence in surface waters across the United States and highlights existing data gaps. Available data are largely from a handful of study areas with known PFAS manufacturing or industrial uses, with much of the data collected from freshwater systems in eastern states and the upper Midwest. Measured PFOS concentrations in surface waters vary widely, over 8 orders of magnitude, with the highest concentrations occurring downstream from manufacturing and industrial use plants, areas near aqueous film-forming foam-use sites, and sites where PFOS precursors were used in textile treatment. Non-point source-related occurrences are highest near urbanized areas with high population densities. Current data illustrate the occurrence of PFOS in surface waters across multiple US states. Additional data are needed to better understand PFOS occurrence in US aquatic ecosystems, particularly in estuarine and marine systems and where monitoring data are not available (e.g., southwestern, central, and western United States). Additional PFOS occurrence data would provide valuable information on potential spatial and temporal variability in surface waters and possible risks posed to aquatic ecosystems. Environ Toxicol Chem 2021;40:2425-2442. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Exposure to perfluorooctane sulfonate reduced cell viability and insulin release capacity of β cells

Per- and polyfluoroalkyl substances (PFAS) are found to have multiple adverse outcomes on human health. Recently, epidemiological and toxicological studies showed that exposure to PFAS had adverse impacts on pancreas and showed association with insulin abnormalities. To explore how PFAS may contribute to diabetes, we studied impacts of perfluorooctane sulfonate (PFOS) on cell viability and insulin release capacity of pancreatic β cells by using in vivo and in vitro methods. We found that 28-day administration with PFOS (10 mg/(kg body weight•day)) caused reductions of pancreas weight and islet size in male mice. PFOS administration also led to lower serum insulin level both in fasting state and after glucose infusion among male mice. For cell-based in vitro bioassay, we used mouse β-TC-6 cancer cells and found 48-hr exposure to PFOS decreased the cell viability at 50 μmol/L. By measuring insulin content in supernatant, 48-hr pretreatment of PFOS (100 μmol/L) decreased the insulin release capacity of β-TC-6 cells after glucose stimulation. Although these concentrations were higher than the environmental concentration of PFOS, it might be reasonable for high concentration of PFOS to exert observable toxic effects in mice considering mice had a faster removal efficiency of PFOS than human. PFOS exposure (50 μmol/L) to β-TC-6 cells induced intracellular accumulation of reactive oxidative specie (ROS). Excessive ROS induced the reactive toxicity of cells, which eventually invoke apoptosis and necrosis. Results in this study provide evidence for the possible causal link of exposure to PFOS and diabetes risk.

Insights into the impacts of bioturbation by multiple benthic organisms on the bioavailability and toxic effects of perfluorooctane sulfonate in sediment

Sediment is an important reservoir for perfluorooctane sulfonate (PFOS) in the environment, which likely poses adverse effects to benthos. In this study, the impacts of bioturbation of three benthic organisms, i.e. Chironomus kiiensis, Hyalella azteca and Limnodrilus hoffmeisteri, on the release of PFOS from sediment were investigated, and the toxic effects of PFOS to C. kiiensis were explored in the presence of one or two of the other benthic organisms. Among the three organisms, C. kiiensis displayed the weakest effect on the distribution of PFOS between sediment and water (P＞0.05). The bioturbation of H. azteca and L. hoffmeisteri distinctly facilitated the suspension of sediment, leading to the enhanced amount of suspended particulate matter (SPM) and the flux of PFOS from sediment to SPM. Consequently, the concentrations of PFOS in the overlying water and pore water decreased significantly. Moreover, both H. azteca and L. hoffmeisteri affected the survival of C. kiiensis, and its mortality increased from 2.8% to 100% and 41.7% respectively. This study provides insights into the influences of bioturbation on the bioavailability of PFOS in sediments, and is helpful for accurately assessing the transport, toxicity and potential risks of PFOS in sediments.

The association between maternal perfluoroalkyl substances exposure and early attention deficit hyperactivity disorder in children: a systematic review and meta-analysis.

Some studies have shown that maternal exposure to perfluoroalkyl substances (PFASs) may be associated with early attention deficit hyperactivity disorder (ADHD) in children. The purpose of this systematic review and meta-analysis is to verify this association by reviewing existing studies and to provide a strong basis for preventing ADHD. The researchers searched electronic databases such as PubMed, Science Direct, Scopus, Google Scholar, Web of Science, and Embase for all studies published before October 2020. Finally, we included nine articles for analysis. Our meta-analysis showed that maternal exposure to PFASs was not significantly associated with the prevalence rate of early childhood ADHD (perfluorooctanoic acid (PFOA), odds ratio (OR) = 1.00, 95% confidence interval (95% CI) = 0.75-1.25; perfluorooctane sulfonate (PFOS), OR = 1.01, 95% CI = 0.88-1.14; perfluorohexane sulfonate (PFHxS), OR = 1.08, 95% CI = 0.80-1.09; perfluorononanoic acid (PFNA), OR = 1.13, 95% CI = 0.99-1.28; perfluorodecanoic acid (PFDA), OR = 1.23, 95% CI = 0.15-2.32). Due to significant heterogeneity, we subsequently performed subgroup analysis and sensitivity analysis. Through subgroup analysis, we found that PFOS concentration of children's blood and the prevalence rate of early childhood ADHD were statistically positively correlated, and there was also a positive correlation between PFOS exposure and the prevalence rate of early childhood ADHD in the America. Moreover, there was also a statistically positive correlation between PFNA concentration in maternal blood and the prevalence rate of early childhood ADHD. Sensitivity analysis showed that the final results did not change much, the sensitivity was low, and the results were relatively stable. In conclusion, a causal relationship between maternal PFASs exposure and ADHD in children was unlikely. Among them, PFOS, PFNA, and ADHD might have positive associations worthy of further investigation.

Invited Perspective: PFAS Bioconcentration and Biotransformation in Early Life Stage Zebrafish and Its Implications for Human Health Protection.

Invited Perspective: PFAS Bioconcentration and Biotransformation in Early Life Stage Zebrafish and Its Implications for Human Health Protection.

Modelling the transport of PFOS from single lined municipal solid waste landfill

The contaminant transport of perfluorooctane sulfonate (PFOS) through the base of a municipal solid waste landfill lined by a single composite liner comprised of a geomembrane over a geosynthetic clay liner (GCL) and a 3.75 m-thick attenuation layer underlain by an aquifer is examined. Both pure diffusive transport and advective transport through holed wrinkles are modelled. The peak concentrations of PFOS predicted for the aquifer beneath the landfill are compared to the maximum allowable PFOS concentration established by Australia, Canada, Europe, and various US states. The results show that (a) in most cases with zero leakage and pure diffusive transport, regulatory limits are met; however, (b) if there are holed wrinkles in the geomembrane, the impact is highly dependent on the length of holed wrinkle per hectare, the geomembrane-GCL interface transmissivity, and the GCL hydraulic conductivity. Factors affecting the length of holed wrinkles are discussed. In many of the cases examined, the peak concentrations of PFOS in the aquifer exceed the limits set by the different jurisdictions, indicating that a single composite liner may not be sufficient to contain PFOS acceptable level and recommends that realistic contaminant impact calculations be performed in each specific case.

Serum levels of perfluorooctanoic acid and perfluorooctane sulfonic acid in pregnant women: Maternal predictors and associations with birth outcomes in the PIPA Project.

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. 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. 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. 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.

Risk Assessment of Perfluorooctane Sulfonate (PFOS) using Dynamic Age Dependent Physiologically based Pharmacokinetic Model (PBPK) across Human Lifetime

The widespread use of Perfluorooctane sulfonate (PFOS) in everyday life, its long half-life, and the lipophilicity that makes it easily accumulate in the body, raises the question of its safe exposure among different population groups. There are currently enough epidemiological studies showing evidence of PFOS exposure and its associated adverse effects on humans. Moreover, it is already known that physiological changes along with age e.g. organ volume, renal blood flow, cardiac output and albumin concentrations affect chemicals body burden. Human biomonitoring cohort studies have reported PFOS concentrations in blood and autopsy tissue data with PFOS present in sensitive organs across all human lifespan. However, to interpret such biomonitoring data in the context of chemical risk assessment, it is necessary to have a mechanistic framework that explains show the physiological changes across age affects the concentration of chemical inside different tissues of the human body. PBPK model is widely and successfully used in the field of risk assessment. The objective of this manuscript is to develop a dynamic age-dependent PBPK model as an extension of the previously published adult PFOS model and utilize this model to predict and compare the PFOS tissue distribution and plasma concentration across different age groups. Different cohort study data were used for exposure dose reconstruction and evaluation of time-dependent concentration in sensitive organs. Predicted plasma concentration followed trends observed in biomonitoring data and model predictions showed the increased disposition of PFOS in the geriatric population. PFOS model is sensitive to parameters governing renal resorption and elimination across all ages, which is related to PFOS half-life in humans. This model provides an effective framework for improving the quantitative risk assessment of PFOS throughout the human lifetime, particularly in susceptible age groups. The dynamic age-dependent PBPK model provides a step forward for developing such kind of dynamic model for other perfluoroalkyl substances.

Adsorption behavior of perfluorooctanesulfonate (PFOS) onto activated spent coffee grounds biochar in synthetic wastewater effluent

Improved understanding of human health risks, environmental persistence, and widespread dispersion of per- and polyfluoroalkyl substances (PFAS) has driven ongoing development of stringent regulations for these compounds in water. Char materials produced from agricultural food waste have recently been explored as alternatives to granular activated carbon for PFAS removal in water. Herein, spent coffee grounds (SCG) were pyrolyzed, activated with alkaline hydroxide, and evaluated for perfluorooctanesulfonate (PFOS) adsorption. At environmentally-relevant PFOS concentrations, pyrolyzed SCG showed minimal PFOS removal while activated SCG removed 9.9%–99.6% of PFOS depending on activation conditions. SCGKOH (produced from a 1:1 mass ratio of pyrolyzed SCG and potassium hydroxide) had a maximum adsorption capacity of 43.4 mg/g compared to Filtrasorb® F300 activated carbon (55.7 mg/g) and a wood-based fly ash char (79.5 mg/g). All adsorbents display non-linear pseudo first-order adsorption behavior with rate constants of 0.414 h−1, 0.062 h−1, 0.090 h−1 for fly-ash biochar, SCGKOH and F300, respectively. Additionally, PFOS removal by all adsorbents decreased in the presence of simulated effluent organic matter. SCGKOH presents an exciting alternative to existing commercial char adsorbents. The widely available feedstock and low-input production process could make this material a viable water treatment option for resource-constrained communities.

Polyacrylonitrile fiber functionalized with fluorous hyperbranched polyethylenimine for selective removal of perfluorooctane sulfonate (PFOS) in firefighting wastewaters

Perfluorooctane sulfonate (PFOS) is a well-known persistent organic pollutant in water systems, especially in firefighting wastewaters. It is highly desirable to develop new adsorbents that can remove PFOS efficiently and selectively from firefighting wastewaters. In this work, polyacrylonitrile (PAN) fiber was functionalized by adding fluorous hyperbranched polyethylenimine (F-PEI) under hydrothermal conditions, generating a series of fluorous PAN-g-F-PEI fibers. Compared with the fiber without perfluoroalkyl chains, the existence of perfluoroalkyl chains significantly shortened the equilibrium adsorption time. Lowering solution pH and increasing the F-PEI content were two more efficient ways to improve the maximum equilibrium adsorption capacity. The introduction of enough perfluoroalkyl chains into the fiber effectively suppressed the adverse effect of zwitterionic surfactants, nonionic surfactants and organic solvents on the PFOS removal efficiency, and also alleviated the adverse effect of anionic surfactants. The PAN-g-F-PEI fiber with the largest amount of perfluoroalkyl chains could efficiently and selectively remove PFOS from the firefighting wastewaters containing a high concentration of PFOS and the residual PFOS concentration could reach below 10 ng/L, satisfying the standard of the U.S. Environmental Protection Agency. Moreover, after adsorption, PAN-g-F-PEIs could be easily regenerated by methanol washing and reused for five times without pronounced loss of adsorption capacity.

Sea turtles across the North Pacific are exposed to perfluoroalkyl substances.

Perfluorinated alkyl substances (PFASs) are global, persistent, and toxic contaminants. We assessed PFAS concentrations in green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles from the North Pacific. Fifteen compounds were quantified via liquid chromatography tandem mass spectrometry from 62 green turtle and 6 hawksbill plasma samples from Hawai'i, Palmyra Atoll, and the Northern Marianas Islands. Plasma from 14 green turtles severely afflicted with fibropapillomatosis, and eggs from 12 Hawaiian hawksbill nests from 7 females were analyzed. Perfluorooctane sulfonate (PFOS) predominated in green turtle plasma; perfluorononanoic acid (PFNA) predominated in hawksbill tissues. Concentrations were greater in hawksbill than green turtle plasma (p<0.05), related to trophic differences. Green turtle plasma PFOS concentrations were related to human populations from highest to lowest: Hawai'i, Marianas, Palmyra. Influence on fibropapillomatosis was not evident. PFASs were maternally transferred to hawksbill eggs, with decreasing concentrations with distance from airports and with clutch order from one female. A risk assessment of PFOS showed concern for immunosuppression in Kailua green turtles and alarming concern for hawksbill developmental toxicity. Perfluoroundecanoic (PFUnA) and perfluorotridecanoic (PFTriA) acid levels were correlated with reduced emergence success (p<0.05). Studies to further examine PFAS effects on sea turtle development would be beneficial.

Efficient PFOS decomposition in an alkaline ultrasonic system

Perfluorooctane sulfonate (PFOS) has attracted increasing attention due to its global distribution, high chemical stability and environmental persistence. An alkaline ultrasonic system was explored and used for PFOS decomposition in this study. kobs of PFOS decomposition in the investigated system was 0.0196 min−1, which was remarkably efficient than that in sole ultrasonic system. eaq − induced reductive decomposition and pyrolysis decomposition based on the collapse of cavitation bubble were found to be two main reasons contributing to PFOS decomposition. PFOS decomposition kinetics was boosted by increasing alkaline dosage and reaction temperature, but suppressed when increasing initial PFOS concentration.

Development of a Gestational and Lactational Physiologically Based Pharmacokinetic (PBPK) Model for Perfluorooctane Sulfonate (PFOS) in Rats and Humans and Its Implications in the Derivation of Health-Based Toxicity Values.

Background:There is a great concern on potential adverse effects of exposure to perfluorooctane sulfonate (PFOS) in sensitive subpopulations, such as pregnant women, fetuses, and neonates, due to its reported transplacental and lactational transfer and reproductive and developmental toxicities in animals and humans.Objectives:This study aimed to develop a gestational and lactational physiologically based pharmacokinetic (PBPK) model in rats and humans for PFOS to aid risk assessment in sensitive human subpopulations.Methods:Based upon existing PBPK models for PFOS, the present model addressed a data gap of including a physiologically based description of basolateral and apical membrane transporter–mediated renal reabsorption and excretion in kidneys during gestation and lactation. The model was calibrated with published rat toxicokinetic and human biomonitoring data and was independently evaluated with separate data. Monte Carlo simulation was used to address the interindividual variability.Results:Model simulations were generally within 2-fold of observed PFOS concentrations in maternal/fetal/neonatal plasma and liver in rats and humans. Estimated fifth percentile human equivalent doses (HEDs) based on selected critical toxicity studies in rats following U.S. Environmental Protection Agency (EPA) guidelines ranged from 0.08 to . These values are lower than the HEDs estimated in U.S. EPA guidance () using an empirical toxicokinetic model in adults.Conclusions:The results support the importance of renal reabsorption/excretion during pregnancy and lactation in PFOS dosimetry and suggest that the derivation of health-based toxicity values based on developmental toxicity studies should consider gestational/lactational dosimetry estimated from a life stage-appropriate PBPK model. This study provides a quantitative tool to aid risk reevaluation of PFOS, especially in sensitive human subpopulations, and it provides a basis for extrapolating to other per- and polyfluoroalkyl substances (PFAS). All model codes and detailed tutorials are provided in the Supplemental Materials to allow readers to reproduce our results and to use this model. https://doi.org/10.1289/EHP7671

Low-pressure volume retarded osmosis for removal of per- and polyfluoroalkyl substances

Forward osmosis is an energy efficient process that is capable of recovering high-quality water from secondary wastewater treatment. However, regeneration of the draw solution (DS) is a problem that needs to be addressed. Herein, we developed and optimized a one-step process that does not require additional treatment for the DS. This process, called pressure assisted-volume retarded osmosis (PA-VRO), utilizes naturally occurring pressure with the aid of a small inlet pressure (< 1 bar). Poly(styrenesulfonate) was employed as the DS, for its high solubility in water and large molecular size (∼70,000 Da). Accordingly, real wastewater was employed as the feed solution for 48 h to remove perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) through PA-VRO. The rejection rates for PFOA/PFOS and poly(sodium-4-styrenesulfonate) (PSS) were observed to exceed 98%, after 24 h and 99%, after 48 h. Moreover, there were no traceable amounts of PFOA/PFOS in the DS, and hence the detected concentrations of PFOA and PFOS can be attributed to the residuals from the equipment. Therefore, this well-optimized PA-VRO process can be utilized for potable water production from treated wastewater.

Uptake, Acropetal Translocation, and Enantioselectivity of Perfluorooctane Sulfonate in Maize Coexisting with Copper.

Plant uptake and translocation of perfluorooctane sulfonate (PFOS) are critical for food safety and raise major concerns. However, those processes are associated with many undisclosed mechanisms, especially when PFOS coexist with heavy metals. In this study, we investigated the effect of copper (Cu) on PFOS distribution in maize tissues by assessing the PFOS concentration and enantioselectivity. The presence of <100 μmol/L Cu exerted a limited effect on PFOS bioaccumulation, while >100 μmol/L Cu damaged the root cell membrane and increased root permeability, resulting in a higher PFOS concentration in roots. The suppression of acropetal translocation might be attributed to Cu inhibition of carrier proteins. The enantiomer fraction (EF) of 1m-PFOS at <100 μmol/L Cu was higher than that in a commercial product (0.5). Racemic PFOS was detected at >100 μmol/L Cu in roots and the EF variation changed from positive to negative in shoots. These EF results evidenced the existence of a protein-mediated uptake pathway. Besides, this study indicated the challenge of chiral signature application in PFOS source identification, given the effects of heavy metals and plants on PFOS enantioselectivity. The findings provide insight into PFOS bioaccumulation in plants cocontaminated with Cu and will facilitate environmental risk assessment.

Perfluorooctanoic acid (PFOA) or perfluorooctane sulfonate (PFOS) and DNA methylation in newborn dried blood spots in the Upstate KIDS cohort

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are persistent organic pollutants which may alter prenatal development, potentially through epigenetic modifications. Prior studies examining PFOS/PFOA and DNA methylation have relatively few subjects (n < 200) and inconsistent results.We examined relations of PFOA/PFOS with DNA methylation among 597 neonates in the Upstate KIDS cohort study. PFOA/PFOS were quantified in newborn dried blood spots (DBS) using high-performance liquid chromatography/tandem mass spectrometry. DNA methylation was measured using the Infinium MethylationEPIC BeadChip with DNA extracted from DBS. Robust linear regression was used to examine the associations of PFOA/PFOS with DNA methylation at individual CpG sites. Covariates included sample plate, estimated cell type, epigenetically derived ancestry, infant sex and plurality, indicators of maternal socioeconomic status, and prior pregnancy loss. In supplemental analysis, we restricted the analysis to 2242 CpG sites previously identified as Correlated Regions of Systemic Interindividual Variation (CoRSIVs) which include metastable epialleles.At FDR<0.05, PFOA concentration >90th percentile was related to DNA methylation at cg15557840, near SCRT2, SRXN1; PFOS>90th percentile was related to 2 CpG sites in a sex-specific manner (cg19039925 in GVIN1 in boys and cg05754408 in ZNF26 in girls). When analysis was restricted to CoRSIVs, log-scaled, continuous PFOS concentration was related to DNA methylation at cg03278866 within PTBP1.In conclusion, there was limited evidence of an association between high concentrations of PFOA/PFOS and DNA methylation in newborn DBS in the Upstate KIDS cohort. These findings merit replication in populations with a higher median concentration of PFOA/PFOS.