Polyfluoroalkyl Substances Concentrations Research Articles

Occurrence and Fate of Per- and Polyfluoroalkyl Substances (PFAS) in Atmosphere: Size-Dependent Gas-Particle Partitioning, Precipitation Scavenging, and Amplification.

The concerns about the fate of per- and polyfluoroalkyl substances (PFAS) in the atmosphere are continuously growing. In this study, size-fractionated particles, gas, and rainwater samples were simultaneously collected in Shijiazhuang, China, to investigate the multiphase distribution of PFAS in the atmosphere. Perfluoroalkyl carboxylic acids (PFCAs) dominated the total concentration of PFAS in atmospheric media. A strong positive relationship (0.79 < R2 < 0.99) was observed between the concentration of PFCAs and organic matter fraction (fOM) in different particle size fractions, while no such relationship for perfluoroalkyl sulfonic acids (PFSAs) and fOM, suggesting fOM may be an important factor influencing the size-dependent distribution of PFCAs. Temperature played a key role in the gas-particle partitioning of PFAS, while it did not significantly affect their particle-size-dependent distribution. The associative concentration fluctuation of particle and particle-bound PFAS during precipitation suggested that precipitation scavenging was an important mechanism for the removal of PFAS from the atmosphere. Furthermore, temporary increases in atmospheric PFAS concentrations were observed during the precipitation. Fugacity ratios of PFAS in rainwater and gas phase (log fR/fG ranged between 2.0 and 6.6) indicated a strong trend for PFAS to diffuse from the rainwater to the gas phase during the precipitation, which may explain that the concentration of PFAS in the gas phase continued to increase even at the end of the precipitation.

Total and Class-Specific Determination of Fluorinated Compounds in Consumer and Food Packaging Samples Using Fluorine-19 Solid-State Nuclear Magnetic Resonance Spectroscopy.

Hamburger wrapping paper, coated with water-based barrier coatings, used in the food packaging industry was studied by using the total organic fluorine (TOF) method based on combustion ion chromatography and fluorine-19 solid-state nuclear magnetic resonance (19F ss-NMR) spectroscopy. Although the TOF method is a fast and affordable method used to screen for per- and polyfluoroalkyl substances (PFAS), the amount of fluorine it measures is heavily dependent on the extraction step and, therefore could lead to inaccurate results. Fluorine-19 ss-NMR spectroscopy can differentiate between organic and inorganic fluorinated sources, eliminating the need for sample clean up. To illustrate this, the 19F ss-NMR spectra of clean coated paper samples that contained naturally occurring F- ions from the talc raw material and spiked samples containing perfluorooctanoic acid were compared. A range of experimental conditions was explored to improve sensitivity for low PFAS concentrations (in the order of 10-20 mg/kg). Despite the disadvantages of ss-NMR spectroscopy, such as the low limit of detection and resolution, the results demonstrate it can be a viable tool to directly detect PFAS moieties in consumer and food packaging. Therefore, 19F solid-state NMR spectroscopy challenges and complements current methods, which only provide indirect evidence of the presence of PFAS.

Adsorption dynamics of per- and polyfluoroalkyl substances (PFAS) on activated carbon: Interplay of surface chemistry and PFAS structural properties

Using activated carbon (AC) to adsorb per- and polyfluoroalkyl substances (PFAS) is highly practical for environmental remediation. However, examining the surface chemistry of carbonaceous material with regard to the removal of various PFAS has been limited, as the focus has often solely been on perfluorooctanoic acid and perfluorooctane sulfonic acid. Consequently, this study systematically explores the role of AC surface chemistry in the adsorption of PFAS with various structural properties using ACs that have been modified for different degrees of acidity, basicity, and hydrophobicity. Batch adsorption studies have demonstrated that the affinity of PFAS for the AC surface is negatively correlated with surface acidity. The removal performance at an adsorbent dose of 2 mg/L and an initial PFAS concentration of 600 ng/L is 27.4–91.4 %, 57.2–95.6 %, 92.4–99.2 %, and 89.1–99.6 % for an AC with an acidic surface, unmodified AC, defunctionalized AC, and AC with basic surface, respectively. Analyses of the adsorption isotherms, kinetics, and removal performance of the four types of ACs and 14 PFAS in water at different pH and ionic strengths reveal that hydrophobic, electron donor–acceptor, and electrostatic interactions, as well as negative charge-assisted hydrogen bond formation are necessary to describe the key adsorption characteristics observed in the experiments. The relative significance of the adsorption mechanisms depends on the PFAS structural properties, AC surface chemistry, and water composition. This extensive discourse contributes substantially to the design of an efficient carbonaceous adsorbent with specific surface moieties for removing PFAS from water.

Association of diet with per- and polyfluoroalkyl substances in plasma and human milk in the New Hampshire Birth Cohort Study

Per- and polyfluoroalkyl substances (PFAS) are related to various adverse health outcomes, and food is a common source of PFAS exposure. Dietary sources of PFAS have not been adequately explored among U.S. pregnant individuals. We examined associations of dietary factors during pregnancy with PFAS concentrations in maternal plasma and human milk in the New Hampshire Birth Cohort Study. PFAS concentrations, including perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), and perfluorodecanoate (PFDA), were measured in maternal plasma collected at ~28 gestational weeks and human milk collected at ~6 postpartum weeks. Sociodemographic, lifestyle and reproductive factors were collected from prenatal questionnaires and diet from food frequency questionnaires at ~28 gestational weeks. We used adaptive elastic net (AENET) to identify important dietary variables for PFAS concentrations. We used multivariable linear regression to assess associations of dietary variables selected by AENET models with PFAS concentrations. Models were adjusted for sociodemographic, lifestyle, and reproductive factors, as well as gestational week of blood sample collection (plasma PFAS), postpartum week of milk sample collection (milk PFAS), and enrollment year. A higher intake of fish/seafood, eggs, coffee, or white rice during pregnancy was associated with higher plasma or milk PFAS concentrations. For example, every 1 standard deviation (SD) servings/day increase in egg intake during pregnancy was associated with 4.4 % (95 % CI: 0.6, 8.4), 3.3 % (0.1, 6.7), and 10.3 % (5.6, 15.2) higher plasma PFOS, PFOA, and PFDA concentrations respectively. Similarly, every 1 SD servings/day increase in white rice intake during pregnancy was associated with 7.5 % (95 % CI: −0.2, 15.8) and 12.4 % (4.8, 20.5) greater milk PFOS and PFOA concentrations, respectively. Our study suggests that certain dietary factors during pregnancy may contribute to higher PFAS concentrations in maternal plasma and human milk, which could inform interventions to reduce PFAS exposure for both birthing people and offspring.

Per- and polyfluoroalkyl substances (PFAS) exposure in plasma and their blood–brain barrier transmission efficiency–A pilot study

Per- and polyfluoroalkyl substances (PFAS) have been shown to penetrate the blood–brain barrier (BBB) and accumulate in human brain. The BBB transmission and accumulation efficiency of PFAS, as well as the potential health risks from human co-exposure to legacy and emerging PFAS due to differences in transport efficiency, need to be further elucidated. In the present pilot study, 23 plasma samples from glioma patients were analyzed for 17 PFAS. The concentrations of PFAS in six paired brain tissue and plasma samples were used to calculate the BBB transmission efficiency of PFAS (RPFAS). This RPFAS analysis was conducted with utmost care and consideration amid the limited availability of valuable paired samples. The results indicated that low molecular weight PFAS, including short-chain and emerging PFAS, may have a greater potential for accumulation in brain tissue than long-chain PFAS. As an alternative to perfluorooctane sulfonic acid (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) exhibited brain accumulation potential similar to that of PFOS, suggesting it may not be a suitable substitute concerning health risk in brain. The BBB transmission efficiencies of perfluorooctanoic acid, PFOS, and 6:2 Cl-PFESA showed similar trends with age, which may be an important factor influencing the entry of exogenous compounds into the brain. A favorable link between perfluorooctane sulfonamide (FOSA) and the development and/or progression of glioma may be implicated by a strong positive correlation (r2 = 0.94; p < 0.01) between RFOSA and Ki-67 (a molecular marker of glioma). However, a causal relationship between RFOSA and glioma incidence were not established in the present study. The present pilot study conducted the first examination of BBB transmission efficiency of PFAS from plasma to brain tissue and highlighted the importance of reducing and/or controlling exposure to PFAS.

Per- and polyfluoroalkyl substances (PFAS) and fetal growth: A nation-wide register-based study on PFAS in drinking water

BackgroundThere is inconclusive evidence for an association between per- and polyfluoroalkyl substances (PFAS) and fetal growth. ObjectivesWe conducted a nation-wide register-based cohort study to assess the associations of the estimated maternal exposure to the sum (PFAS4) of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) with birthweight as well as risk of small- (SGA) and large-for-gestational-age (LGA). Materials and methodsWe included all births in Sweden during 2012–2018 of mothers residing ≥ four years prior to partus in localities served by municipal drinking water where PFAS were measured in raw and drinking water. Using a one-compartment toxicokinetic model we estimated cumulative maternal blood levels of PFAS4 during pregnancy by linking residential history, municipal PFAS water concentration and year-specific background serum PFAS concentrations in Sweden. Individual birth outcomes and covariates were obtained via register linkage. Mean values and 95 % confidence intervals (CI) of β coefficients and odds ratios (OR) were estimated by linear and logistic regressions, respectively. Quantile g-computation regression was conducted to assess the impact of PFAS4 mixture. ResultsAmong the 248,804 singleton newborns included, no overall association was observed for PFAS4 and birthweight or SGA. However, an association was seen for LGA, multivariable-adjusted OR 1.08 (95% CI: 1.01–1.16) when comparing the highest PFAS4 quartile to the lowest. These associations remained for mixture effect approach where all PFAS, except for PFOA, contributed with a positive weight. DiscussionsWe observed an association of the sum of PFAS4 – especially PFOS – with increased risk of LGA, but not with SGA or birthweight. The limitations linked to the exposure assessment still require caution in the interpretation.

Prenatal exposure to per- and polyfluoroalkyl substances, fetal thyroid function, and intelligence quotient at 7 years of age: Findings from the Sheyang Mini Birth Cohort Study

BackgroundPrenatal exposure to per- and polyfluoroalkyl substances (PFASs) influences neurodevelopment. Thyroid homeostasis disruption is thought to be a possible underlying mechanism. However, current epidemiological evidence remains inconclusive. ObjectivesThis study aimed to explore the effects of prenatal PFAS exposure on the intelligence quotient (IQ) of school-aged children and assess the potential mediating role of fetal thyroid function. MethodsThe study included 327 7-year-old children from the Sheyang Mini Birth Cohort Study (SMBCS). Cord serum samples were analyzed for 12 PFAS concentrations and 5 thyroid hormone (TH) levels. IQ was assessed using the Wechsler Intelligence Scale for Children-Chinese Revised (WISC-CR). Generalized linear models (GLM) and Bayesian Kernel Machine Regression (BKMR) were used to evaluate the individual and combined effects of prenatal PFAS exposure on IQ. Additionally, the impact on fetal thyroid function was examined using a GLM, and a mediation analysis was conducted to explore the potential mediating roles of this function. ResultsThe molar sum concentration of perfluorinated carboxylic acids (ΣPFCA) in cord serum was significantly negatively associated with the performance IQ (PIQ) of 7-year-old children (β = -6.21, 95 % confidence interval [CI]: −12.21, −0.21), with more pronounced associations observed among girls (β = -9.57, 95 % CI: −18.33, −0.81) than in boys. Negative, albeit non-significant, cumulative effects were noted when considering PFAS mixture exposure. Prenatal exposure to perfluorooctanoic acid, perfluorononanoic acid, and perfluorooctanesulfonic acid was positively associated with the total thyroxine/triiodothyronine ratio. However, no evidence supported the mediating role of thyroid function in the link between PFAS exposure and IQ. ConclusionsIncreased prenatal exposure to PFASs negatively affected the IQ of school-aged children, whereas fetal thyroid function did not serve as a mediator in this relationship.

Sources of per- and polyfluoroalkyl substances in an arid, urban, wastewater-dominated watershed

Per- and polyfluoroalkyl substances (PFAS) enter surface waters from various sources such as wastewater treatment plants, fire-fighting sites, and PFAS-producing and PFAS-using industries. The Las Vegas Wash in Southern Nevada of the United States (U.S.) conveys wastewater effluent from the Las Vegas metropolitan area to Lake Mead, a drinking water source for millions of people in the U.S. Southwest. PFAS have previously been detected in the Las Vegas Wash, but PFAS sources were not identified. In this study, upstream wash tributaries, wastewater treatment effluents, and shallow groundwater wells were sampled in multiple campaigns during dry-weather conditions to investigate possible PFAS sources. Out of 19 PFAS, two short-chain PFAS—perfluoropentanoic acid (48 % of the total molar concentration) and perfluorohexanoic acid (32 %)—comprised the majority of PFAS loading measured in the Las Vegas Wash, followed by perfluorooctanoic acid (9 %). On a mass loading basis, the majority of total measured PFAS (approximately 90 %) and at least 48 % of each specific PFAS in the Las Vegas Wash likely entered via municipal wastewater effluents, of which the main source was likely residential wastewater. One of the drainage areas with a major civilian airport was identified as a potential source of relatively enriched perfluorosulfonic acids to a small wash tributary and shallow groundwater samples. Nonetheless, that tributary contributed at most 15 % of any specific PFAS to the mainstem of the Las Vegas Wash. Total PFAS concentrations were relatively low for the small tributary associated with an urban smaller airport and the lack of flow in the tributary channel immediately downgradient of an Air Force Base indicates the smaller airport and base were unlikely significant PFAS sources to the Las Vegas Wash. Overall, this study demonstrated effective PFAS source investigation methodology and the importance of wastewater effluent as a PFAS environmental pathway.

Passive biomonitoring for per- and polyfluoroalkyl substances using invasive clams, C. fluminea

Per- and polyfluoroalkyl substances (PFAS) are a class of toxic manufactured chemicals in commercial and consumer products. They are resistant to environmental degradation and mobile in soil, air, and water. This study used the introduced bivalve Corbicula fluminea as a passive biomonitor at sampling locations in a primary drinking water source in Virginia, USA. Many potential PFAS sources were identified in the region. Perfluorohexane sulfonate (PFHxS) and 6:2 fluorotelomer sulfonic acid (6:2 FTS) levels were highest downstream of an airport. The highest levels of short-chain carboxylic acids were in locations downstream of a wastewater treatment plant. Measured PFAS concentrations varied by location in C. fluminea, sediment, and surface water samples. Two compounds were detected across all three mediums. Calculated partitioning coefficients confirm bioaccumulation of PFAS in C. fluminea and sorption to sediment. C. fluminea bioaccumulated two PFAS not found in the other mediums. Perfluoroalkyl carboxylic acids and short-chain compounds dominated in clam tissue, which contrasts with findings of accumulation of longer-chain and perfluorosulfonic acids in fish. These findings suggest the potential for using bivalves to complement other organisms to better understand the bioaccumulation of PFAS and their fate and transport in a freshwater ecosystem.

A Multiple Lines of Evidence Approach to Demonstrate Effectiveness of PFAS Remediation Technologies

AbstractSignificant investments have been made to develop treatment technologies, particularly destructive approaches, for a variety of per‐ and polyfluoroalkyl substances (PFAS) that are present in groundwater, surface water, and other environmental media. A multiple lines of evidence approach were developed to assist regulators, funding agencies, and practitioners in evaluating PFAS treatment technology performance. This article describes each of three lines of evidence that a technology is effective: (1) decrease in target PFAS concentrations is observed; (2) PFAS treatment transformation products are identified and quantified; and (3) a treatment mechanism is proposed that is consistent with previous studies and supported by data. Other considerations are also described to inform conclusions about knowledge gaps and priorities for future testing. Collectively, these lines of evidence and other considerations help communicate the complexities of PFAS treatment, strengthen research plans, standardize technology evaluator reviews, and inform realistic expectations of PFAS treatment technologies.

Changes in plasma concentrations of per- and Polyfluoroalkyl substances after bariatric surgery in adolescents from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) study

Exposure to per- and poly-fluoroalkyl substances (PFAS) is ubiquitous due to their persistence in the environment and in humans. Extreme weight loss has been shown to influence concentrations of circulating persistent organic pollutants (POPs). Using data from the multi-center perspective Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort, we investigated changes in plasma-PFAS in adolescents after bariatric surgery. Adolescents (Mean age = 17.1 years, SD = 1.5 years) undergoing bariatric surgery were enrolled in the Teen-LABS study. Plasma-PFAS were measured at the time of surgery and then 6-, 12-, and 36 months post-surgery. Linear mixed effect models were used to evaluate longitudinal changes in plasma-PFAS after the time of bariatric surgery. This study included 214 adolescents with severe obesity who had available longitudinal measures of plasma-PFAS and underwent bariatric surgery between 2007 and 2012. Underlying effects related to undergoing bariatric surgery were found to be associated with an initial increase or plateau in concentrations of circulating PFAS up to 6 months after surgery followed by a persistent decline in concentrations of 36 months (p < 0.001 for all plasma-PFAS). Bariatric surgery in adolescents was associated with a decline in circulating PFAS concentrations. Initially following bariatric surgery (0–6 months) concentrations were static followed by decline from 6 to 36 months following surgery. This may have large public health implications as PFAS are known to be associated with numerous metabolic related diseases and the significant reduction in circulating PFAS in individuals who have undergone bariatric surgery may be related to the improvement of such metabolic related diseases following bariatric surgery.

Associations between serum perfluoroalkyl and polyfluoroalkyl concentrations and diabetes mellitus in the Korean general population: Insights from the Korean National Environmental Health Survey 2018–2020

AimsRecent epidemiologic research has examined the relationship between perfluoroalkyl and polyfluoroalkyl substances (PFAS) and diabetes mellitus with inconclusive findings. In this cross-sectional study, we aimed to explore the association between serum PFAS concentrations and the prevalence of prediabetes and pre-diagnostic diabetes in the general Korean population as well as the combined effects of exposure to mixed PFAS compounds. MethodsWe analyzed data from participants aged ≥19 years enrolled in the Korean National Environmental Health Survey Cycle 4 (2018–2020). Individuals diagnosed with diabetes were excluded to minimize potential bias. We identified cases of pre-diagnostic diabetes based on the HbA1c level ≥6.5% and prediabetes as HbA1c levels of 5.7–6.49%. Serum concentrations of PFAS, including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDeA), perfluorohexane sulfonic acid (PFHxS), and perfluorooctane sulfonic acid (PFOS), were quantified using high-performance liquid chromatography-tandem mass spectrometry. Survey-weighted logistic regression models were used to assess the relationships between PFAS levels and diabetes risk, adjusting for covariates. Additionally, Bayesian kernel machine regression (BKMR) was used to investigate the combined effects of exposure to mixed PFAS compounds. ResultsIn the study population excluding participants with diagnosed diabetes (n = 2709), the prevalence of pre-diagnostic diabetes and prediabetes was 4.8% and 30.1%, respectively. Significant positive associations were found between serum PFHxS and PFOS quartiles and pre-diagnostic diabetes risk. Likewise, among those without diagnosed or pre-diagnostic diabetes (n = 2579), the highest quartiles of PFDeA, PFHxS, and PFOS and the overall PFAS level were associated with an increased risk of prediabetes compared with the lowest quartiles. BKMR analysis revealed a significant positive association between overall serum PFAS level and prediabetes risk, which was most marked for PFOS. ConclusionsThese findings highlight the potential health implications of PFAS exposure and prediabetes risk. Further research is needed to validate these associations and identify potential mechanistic pathways.

Characterization of per- and polyfluoroalkyl substances (PFAS) and other constituents in MSW landfill leachate from Puerto Rico

Elevated per- and polyfluoroalkyl substance (PFAS) concentrations have been reported in municipal solid waste (MSW) landfill leachate with higher levels in wet and warmer subtropical climates. Information about landfill leachate characteristics is much more limited in tropical climates. In this study, 20 landfill leachate samples were collected from three MSW landfills on the tropical island of Puerto Rico and results were compared against landfills nationally and within Florida, USA. The samples collected in Puerto Rico underwent physical-chemical analysis, as well as a quantitative analysis of 92 PFAS. Samples described in this study include discrete leachate types, such as leachate, gas condensate, and leachate which has undergone on-site treatment (e.g., RO treatment, phytoremediation, lagoons). A total of 51 PFAS were detected above quantitation limits, including perfluorohexylphosphonic acid, a perfluoroalkyl acid (PFAA) which has not been reported previously in landfill leachate. ∑PFAS concentrations in this study (mean: 38,000 ng L−1), as well as concentrations of individual PFAS, are significantly higher than other reported MSW landfill leachate concentrations. The profiles of leachates collected from on-site treatment systems indicate possible transformation of precursor PFAS as a result of treatment processes – oxidizing conditions, for example, may facilitate aerobic transformation, increase the concentrations of PFAAs, and possibly increase the apparent ∑PFAS concentration. Extreme climate events, including rising temperatures and more frequent hurricanes, have placed additional strain on the solid waste management infrastructure on the island – adding complexity to an already challenging PFAS management issue. As concern grows over PFAS contamination in drinking water, these findings should inform solid waste and leachate management decisions in order to minimize PFAS emissions in island environments.

Preliminary Screening of Per- and Polyfluoroalkyl Substances (PFAS) in Philippine Fast Food Packaging Using Liquid Chromatography–Mass Spectrometry (LC-MS)

Per- and polyfluoroalkyl substances (PFAS) on paper packaging resist water and oil to effectively contain food and beverages. However, previous studies have established correlations between PFAS and several diseases including COVID-19, cancers, and obesity. The goal of this collaborative research between the Philippines and Singapore is to set a baseline for PFAS levels in local packaging with the intended outcome of further increasing awareness on these contaminants in Southeast Asia, providing a starting point for migration experiments and risk assessments on PFAS in commercially-available food contact materials and articles, and initiating policy developments on these substances in the Philippines. In this study, 15 different types of PFAS were analyzed in selected paper packaging used by major quick service restaurants (QSRs) in Metro Manila. Using liquid chromatography-mass spectrometry (LC-MS), PFAS was detected in 100% of the samples with a total PFAS concentration range of 8.20-97.7 ng PFAS/100 cm2. The highest amount of PFAS compound measured across all samples was PF-3,7-DMOA (89.8 ng/100 cm2). PFAS compounds regulated in European packaging such as PFHpA, PFOA, PFNA and PFDA were also detected in all samples but at trace levels. Paper wrappers for rice and small burgers were found to have the highest total PFAS of 97.7 ng PFAS/100 cm2. This value translates to approximately 65.1 ng F/100 cm2 which is way below 10,000 ng F/100 cm2, the currently existing limit for PFAS in packaging set by the Danish Ministry of Environment and Food. While each packaging may be deemed safe compared to regulation, the compounded effects brought by use of multiple packaging, and high frequency and long-term exposures require further investigation.

Spatial distribution, source, and fate of per- and polyfluoroalkyl substances in the surrounding environment of closed and converted fluorochemical factories in Fujian, China

Following the closure of perfluorooctanesulfonic acid (PFOS) production to comply with the Stockholm Convention regulations or restrictions, manufacturers have shifted to developing short-chain alternatives like perfluorobutane sulfonic acid (PFBS). However, limited research has been conducted to evaluate the impact of this transition on the surrounding environment. This study focused on the spatial distribution, source, and fate of 18 per- and polyfluoroalkyl substances (PFAS) in the surrounding environment of the closure and transformation of two PFAS manufacturing plants in Fujian, China. The total concentrations of PFAS in surface water, sediment, and fish were within the range of 48.9–72,400 ng/L, 0.930–57.6 ng/g dw, and 3.33–1245 ng/g dw, respectively. The predominant compounds were PFBS, PFOS, and perfluorooctanoic acid (PFOA) among the three matrices. Principal component analysis highlighted significant differences in PFAS profiles across different regions of the Futun River, suggesting diverse sources of PFAS. Source apportionment indicated that despite being closed or converted for almost three years, the two factories still significantly impacted the surrounding environment. The shutdown factory mainly released PFAS characterized by perfluoroalkyl sulfonic acids. In contrast, the PFAS were released from conversion plant with the fingerprint being PFBS and perfluoroalkyl carboxylic acids. The conversion of the factories has resulted in the coexistence of long-chain and short-chain PFAS, which has complicated the composition of PFAS in the environment. As sewage treatment plant could not effectively remove PFBS and perfluorobutanoic acid (PFBA) in wastewater, and due to their strong migration ability, these chemicals had a wider impact range, increasing the difficulty of environmental restoration and management. Risk assessment showed that PFAS downstream of the two factories posed high or moderate ecological risks. Specifically, PFBS, PFOS, and PFOA displayed the highest risk quotients and should be paid further attention.

Incidence of per- and polyfluoroalkyl substances (PFAS) in private drinking water supplies in Southwest Virginia, USA

Per- and polyfluoroalkyl substances (PFAS) are a class of man-made contaminants of human health concern due to their resistance to degradation, widespread environmental occurrence, bioaccumulation in living organisms, and potential negative health impacts. Private drinking water supplies may be uniquely vulnerable to PFAS contamination in impacted areas, as these systems are not protected under federal regulations and often include limited treatment or remediation, if contaminated, prior to use. The goal of this study was to determine the incidence of PFAS contamination in private drinking water supplies in two counties in Southwest Virginia, USA (Floyd and Roanoke) that share similar bedrock geologies, are representative of different state Department of Health risk categories, and to examine the potential for reliance on citizen-science based strategies for sample collection in subsequent efforts. Samples for inorganic ions, bacteria, and PFAS analysis were collected on separate occasions by participants and experts at the home drinking water point of use (POU) for comparison. Experts also collected outside tap samples for analysis of 30 PFAS compounds. At least one PFAS was detectable in 95 % of POU samples collected (n = 60), with a mean total PFAS concentration of 23.5 ± 30.8 ppt. PFOA and PFOS, two PFAS compounds which presently have EPA health advisories, were detectable in 13 % and 22 % of POU samples, respectively. On average, each POU sample contained >3 PFAS compounds, and one sample contained as many as 8 compounds, indicating that exposure to a mixture of PFAS in drinking water may be occurring. Although there were significant differences in total PFAS concentrations between expert and participant collected samples (Wilcoxon, alpha = 0.05), collector bias was inconsistent, and may be due to the time of day of sampling (i.e. morning, afternoon) or specific attributes of a given home. Further research is required to resolve sources of intra-sample variability.

Per- and polyfluoroalkyl substances (PFAS), perceived stress, and depressive symptoms in a prospective cohort study of black women

BackgroundPer- and polyfluoroalkyl substances (PFAS) are endocrine-disrupting chemicals with neurotoxic properties. PFAS have been associated with depressive symptoms among women in some studies, but little research has evaluated the effects of PFAS mixtures. Further, no study has investigated interactions of PFAS-depression associations by perceived stress, which has been shown to modify the effects of PFAS on other health outcomes. ObjectiveIn a prospective cohort study of reproductive-aged Black women, we investigated associations between PFAS and depressive symptoms and the extent to which perceived stress modified these associations. MethodsWe analyzed data from 1499 participants (23-35 years) in the Study of Environment, Lifestyle, and Fibroids. We quantified concentrations of nine PFAS in baseline plasma samples using online solid-phase extraction-liquid chromatography-isotope dilution tandem mass spectrometry. Participants reported perceived stress via the Perceived Stress Scale (PSS-4; range = 0-16) at baseline and depressive symptoms via the Center for Epidemiologic Studies Depression Scale (CESD; range = 0-44) at the 20-month follow-up visit. We used Bayesian Kernel Machine Regression to estimate associations between PFAS concentrations, individually and as a mixture, and depressive symptoms, and to assess effect modification by PSS-4 scores, adjusting for confounders. ResultsBaseline perfluorodecanoic acid concentrations were associated with greater depressive symptoms at the 20-month follow-up, but associations for other PFAS were null. The PFAS were not associated with depressive symptoms when evaluated as a mixture. The association between the 90th percentile (vs. 50th percentile) of the PFAS mixture with CES-D scores was null at the 10th (β = 0.03; 95 % CrI = 0.20, 0.25), 50th (β = 0.02; 95 % CrI = -0.16, 0.19), and 90th (β = 0.01; 95 % CrI = 0.18, 0.20) percentiles of PSS-4 scores, suggesting perceived stress did not modify the PFAS mixture. ConclusionIn this prospective cohort study, PFAS concentrations—assessed individually or as a mixture—were not appreciably associated with depressive symptoms, and there was no evidence of effect modification by perceived stress.

Exposure to per- and polyfluoroalkyl substances in lung cancer patients and their associations with clinical health indicators

Per- and polyfluoroalkyl substances (PFASs) have potential carcinogenicity, immunotoxicity, and hepatotoxicity. Research has been conducted on PFAS exposure in people to discuss their potential health effects, excluding lung cancer. In this study, we recruited participants (n = 282) with lung cancer from Heilongjiang Province, northeast China. The PFAS concentrations were measured in their serum to fill the data gap of exposure, and relationships were explored in levels between PFASs and clinical indicators of tumor, immune and liver function. Ten PFASs were found in over 80 % of samples and their total concentrations were 5.27–152 ng/mL, with the highest level for perfluorooctanesulfonate (median: 12.4 ng/mL). Long-chain PFASs were the main congeners and their median concentration (20.5 ng/mL) was nearly three times to that of short-chain PFASs (7.61 ng/mL). Significantly higher concentrations of perfluorobutanoic acid, perfluorononanoic acid and perfluorohexanesulfonate were found in males than in females (p < 0.05). Serum levels of neuro-specific enolase were positively associated with perfluoropentanoic acid in all participants and were negatively associated with perfluorononanesulfonate in females (p < 0.05, multiple linear regression models). Exposure to PFAS mixture was significantly positively associated with the lymphocytic absolute value (difference: 0.224, 95% CI: 0.018, 0.470; p < 0.05, quantile g-computation models) and serum total bilirubin (difference: 2.177, 95% CI: 0.0335, 4.33; p < 0.05). Moreover, PFAS exposure can affect γ-glutamyl transpeptidase through several immune markers (p < 0.05, mediating test). Our results suggest that exposure to certain PFASs could interfere with clinical indicators in lung cancer patients. To our knowledge, this is the first study to detect serum PFAS occurrence and check their associations with clinical indicators in lung cancer patients.

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and associations with hypertensive disorders of pregnancy in the Atlanta African American Maternal-Child cohort

BackgroundPer- and polyfluoroalkyl substances (PFAS) are man-made chemicals that are slow to break down in the environment and widely detected in humans. Epidemiological evidence suggests that prenatal exposure to perfluorooctanoic acid (PFOA), a legacy PFAS, is linked to gestational hypertension and preeclampsia. However, the relationship between other PFAS, which are structurally similar, and these outcomes remains largely understudied, despite biologic plausibility. Here, we examined associations between serum PFAS mixtures in relation to hypertensive disorders of pregnancy within a birth cohort of African Americans. MethodsParticipants in the present study were enrolled in the Atlanta African American Maternal-Child cohort between 2014 and 2020 (n = 513). Serum samples collected between 8 and 14 weeks gestation were analyzed for four PFAS. Logistic regression was used to assess associations between individual natural log transformed PFAS and specific hypertensive disorders of pregnancy (preeclampsia, gestational hypertension), while quantile g-computation was used to estimate mixture effects. Preeclampsia and gestational hypertension were treated as separate outcomes in individual models. All models were adjusted for maternal education, maternal age, early pregnancy body mass index, parity, and any alcohol, tobacco, or marijuana use. ResultsThe geometric mean of PFOS and PFHxS was slightly lower among those with preeclampsia relative to those without a hypertensive disorder (e.g., geometric mean for PFOS was 1.89 and 1.94, respectively). Serum concentrations of PFAS were not strongly associated with gestational hypertension or preeclampsia in single pollutant or mixture models. For example, using quantile g-computation, a simultaneous one quartile increase in all PFAS was not associated with odds of gestational hypertension (odds ratio = 0.86, 95% CI = 0.60, 1.23), relative to those without a hypertensive disorder of pregnancy. ConclusionsIn this birth cohort of African Americans, there was no association between serum PFAS measured in early pregnancy and hypertensive disorders of pregnancy, which may be reflective of the fairly low PFAS levels in our study population.

Association between per- and poly-fluoroalkyl substances and nonalcoholic fatty liver disease: A nested case-control study in northwest China

Per- and poly-fluoroalkyl substances (PFAS) have been reported to have hepatotoxic effects. However, it is unclear whether they are linked to non-alcoholic fatty liver disease (NAFLD). This nested case-control study focused on the epidemiological links between PFAS and the prevalence of NAFLD. We selected 476 new cases of NAFLD and 952 age- and sex-matched controls from the Jinchang cohort population between 2014 and 2019. Serum concentrations of PFAS were measured using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Only PFAS with a detection rate of ≥90 % were included for analysis, which included PFPeA, PFOA, PFNA, PFHxS, PFOS, and 9Cl-PF3ONS. The relationship between single and co-exposure to PFAS and the occurrence of NAFLD was evaluated using conditional logistic regression, Quantile g-computation (QgC), and Bayesian kernel machine regression (BKMR) model. Logistic regression indicated that PFPeA, PFOA, and 9Cl-PF3ONS were positive correlation with the incidence of NAFLD after adjusting for confounders, with odds ratios (OR) and 95 % confidence interval (CI) of 3.13 (95 % CI: 2.53, 3.86), 1.39 (95 % CI: 1.12, 1.73), and 1.41 (95 % CI: 1.20, 1.66), respectively. PFNA, PFHxS, and PFOS were nonlinearly and negatively associated with the incidence of NAFLD, with OR (95 % CI) of 0.53 (0.46, 0.62), 0.83 (0.73, 0.95), and 0.52 (0.44, 0.61), respectively. QgC showed a significant joint effect of PFAS mixture on NAFLD onset (OR: 1.52, 95 % CI: 1.24, 1.88). BKMR showed a weak positive trend between PFAS mixtures and NAFLD incidence. Positive correlations were primarily driven by PFPeA and 9Cl-PF3ONS, while negative correlations were mainly influenced by PFNA and PFOS. The BKMR model also suggested that there was an interaction between PFOS and PFNA and other four PFAS compounds. In conclusion, our findings suggest that individual and co-exposure to PFAS is associated with a risk of NAFLD onset.