Evidence of Air Dispersion: HFPO-DA and PFOA in Ohio and West Virginia Surface Water and Soil near a Fluoropolymer Production Facility

Rethinking alternatives to fluorinated pops in aqueous environment and corresponding destructive treatment strategies

Alternatives are being developed to replace fluorinated persistent organic pollutants (POPs) listed in the Stockholm Convention, bypass environmental regulations, and overcome environmental risks. However, the extensive usage of fluorinated POPs alternatives has revealed potential risks such as high exposure levels, long-range transport properties, and physiological toxicity. Therefore, it is imperative to rethink the alternatives and their treatment technologies. This review aims to consider the existing destructive technologies for completely eliminating fluorinated POPs alternatives from the earth based on the updated classification and risks overview. Herein, the types of common alternatives were renewed and categorized, and their risks to the environment and organisms were concluded. The efficiency, effectiveness, energy utilization, sustainability, and cost of various degradation technologies in the treatment of fluorinated POPs alternatives were reviewed and evaluated. Meanwhile, the reaction mechanisms of different fluorinated POPs alternatives are systematically generalized, and the correlation between the structure of alternatives and the degradation characteristics was discussed, providing mechanistic insights for their removal from the environment. Overall, the review supplies a theoretical foundation and reference for the control and treatment of fluorinated POPs alternatives pollution.

PFOA-contaminated soil remediation: a comprehensive review

Soil and groundwater contamination has been raised as a concern due to the capability of posing a risk to human health and ecology, especially in facing highly toxic and emerging pollutants. Because of the prevalent usage of perfluorooctanoic acid (PFOA), in industrial and production processes, and subsequently the extent of sites contaminated with these pollutants, cleaning up PFOA polluted sites is paramount. This research provides a review of remediation approaches that have been used, and nine remediation techniques were reviewed under physical, chemical, and biological approaches categorization. As the pollutant specifications, environmental implications, and adverse ecological effects of remediation procedures should be considered in the analysis and evaluation of remediation approaches, unlike previous research that considered a couple of PFAS pollutants and generally dealt with technical issues, in this study, the benefits, drawbacks, and possible environmental and ecological adverse effects of PFOA-contaminated site remediation also were discussed. In the end, in addition to providing sufficient and applicable understanding by comprehensively considering all aspects and field-scale challenges and obstacles, knowledge gaps have been found and discussed.

Adapting to PFAS contamination of private drinking water wells near a PFAS production facility in the US Atlantic Coastal Plain of North Carolina

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widespread groundwater contaminants and are present in over 7000 drinking water wells near a North Carolina (NC) PFAS plant (Chemours). To understand options available to affected residents, we used new and previously existing water quality data to investigate deeper aquifers as alternate drinking water supplies and compared the regulatory responses near Chemours and three other PFAS production facilities with nearby contaminated wells. Data from >100 wells show that GenX concentrations decrease with increasing depth through the four aquifers in the study area: surficial, Black Creek, Upper Cape Fear, and bedrock. This illustrates the extent of vertical PFAS penetration through the aquifer sequence following roughly 40 years of atmospheric emissions. Detailed data on 143 water quality parameters in nine deep wells (two Upper Cape Fear, seven bedrock) revealed only eight exceedances of drinking water standards (one each for arsenic, perfluorooctanoic acid [PFOA], iron, chloride, and gross alpha, and three for manganese) and nine exceedances of health advisories (all for sodium). Regulatory responses to PFAS contamination of wells in four states included mention of deeper wells as an alternate water source only for nonresidential users in NC and residential users in Vermont. The bedrock aquifer is currently used by some residents and may be a viable alternative to shallower groundwater, though arsenic treatment may be beneficial at some deep wells and long-term sustainability of the aquifer should be evaluated. PRACTITIONER POINTS: GenX concentrations decreased with increasing depth in four aquifers near a PFAS plant. A few exceedances of drinking water standards and health advisories were found in deep bedrock wells. New bedrock wells could be part of the response to PFAS issues in shallower wells. In the long term, deep bedrock wells might be a less expensive option for some residents.

[Synthesis of fluorinated nitrogen-rich porous organic polymers and removal of perfluorooctanoic acid from water]

Perfluorooctanoic acid (PFOA) is a persistent contaminant with detrimental effects on the natural environment. This persistence leads to potential enrichment and osmotic transfer, which can affect normal circulation in the environment. PFOA poses significant threats to both the natural environment and human health. Therefore, the development of cost-effective, highly efficient, and environment-friendly PFOA adsorbents is a crucial endeavor. This paper presents the catalyst-free one-pot synthesis of fluorinated nitrogen-rich porous organic polymers (POP-3F) via a Schiff-base condensation reaction. The reaction between the nitrogen-rich compound 1,4-bis(2,4-diamino-1,3,5-triazine)benzene and p-trifluoromethylbenzaldehyde yielded POP-3F. The introduction of fluorine atoms into the nitrogen-rich porous organic polymer enhanced its hydrophobicity, thereby facilitating favorable fluoro-fluorine interactions with PFOA and, thus, improving the efficacy of the adsorbent. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), solid-state nuclear magnetic resonance (ssNMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis, and thermogravimetric analysis (TGA) were used to confirm the successful synthesis and characterization of POP-3F. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was conducted in negative electrospray ionization (ESI) mode coupled with multi-reaction monitoring mode (MRM). The instrument was equipped with an Atlantis T3 column (100 mm×2.1 mm, 3 μm), and analysis was conducted using an external standard method. The influences of various factors on PFOA adsorption by POP-3F, including pH, salt concentration, and humic acid presence, were investigated. The highest PFOA removal rate (98.6%) was achieved at a pH of 2, indicating the applicability of POP-3F for the effective removal of PFOA from acidic industrial wastewater. The removal rate of PFOA was unaffected by increases in NaCl concentration. This phenomenon can be attributed to electrostatic interactions between the protonated secondary amines in POP-3F and deprotonated PFOA. Upon the addition of NaCl, a double electric layer is formed on the POP-3F surface, with Cl- ions in the outer layer and Na+ ions in the inner layer, which weakened these interactions. Humic acid is competitively adsorbed with PFOA. However, POP-3F demonstrated good removal rates even in the presence of high humic acid concentrations in water. Adsorption isotherm and kinetics experiments were conducted at the optimal pH to explore the relevant adsorption mechanism. The results showed a rapid initial adsorption rate, with 95.4% PFOA removal within 5 min. Optimal adsorption equilibrium was achieved within 6 h, and the removal rate decreased by only 0.3% after 24 h. This finding indicates that POP-3F exhibits sustained efficacy for PFOA removal. Langmuir fitting analysis revealed a theoretical maximum adsorption capacity of 191 mg/g for POP-3F; this value surpasses those of activated carbon materials and most other adsorbents, highlighting the superior PFOA-adsorption performance of POP-3F. Additionally, matrix effects minimally affected the removal of PFOA by POP-3F, with only a slight reduction (0.1%) observed in simulated natural water. The recyclability of POP-3F was assessed over five adsorption-desorption cycles. The removal efficenecy exhibited a minor decrease of only 0.67% after five cycles. These results demonstrate the recyclability of the proposed adsorbent, which translates into cost reduction through reusability. This characteristic renders POP-3F a promising candidate for the economical and efficient removal of PFOA from wastewater in practical applications.

Environmental occurrence, bioaccumulation and human risks of emerging fluoroalkylether substances: Insight into security of alternatives

Per- and polyfluoroalkyl substances (PFASs) are widely used due to their unique structure and excellent performance, while also posing threats on ecosystem, especially long-chain perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). As the control of conventional PFASs, fluoroalkylether substances (ether-PFASs) as alternatives are constantly emerging. Subsequently, the three representative ether-PFASs, chlorinated polyfluoroalkyl ether sulfonic acid (F-53B), hexafluoropropylene oxide-dimer acid (HFPO-DA), and 4,8-Dioxa-3H-perfluorononanoicacid (ADONA) are discovered and have received more attention in the environment and ecosystem. But their security is now also being challenged. This review systematically assesses their security from six dimensions including environmental occurrence in water, soil and atmosphere, as well as bioaccumulation and risk in plants, animals and humans. High substitution level is observed for F-53B, whether in environment or living things. Like PFOS or even more extreme, F-53B exhibits high biomagnification ability, transmission efficiency from maternal to infant, and various biological toxicity effects. HFPO-DA still has a relatively low substitution level for PFOA, but its use has emerged in Europe. Although it is less detected in human bodies and has a higher metabolic rate than PFOA, the strong migration ability of HFPO-DA in plants may pose dietary safety concerns for humans. Research on ADONA is limited, and currently, it is detected in Germany frequently while remaining at trace levels globally. Evidently, F-53B has shown increasing risk both in occurrence and toxicity compared to PFOS, and HFPO-DA is relatively safe based on available data. There are still knowledge gaps on security of alternatives that need to be addressed.

Structural dependence of PFAS oxidation in a boron doped diamond-electrochemical system

Driven by long-term persistence and adverse health impacts of legacy perfluorooctanoic acid (PFOA), production has shifted towards shorter chain analogs (C4, perfluorobutanoic acid (PFBA)) or fluorinated alternatives such as hexafluoropropylene oxide dimer acid (HFPO-DA, known as GenX) and 6:2 fluorotelomer carboxylic acid (6:2 FTCA). Yet, a thorough understanding of treatment processes for these alternatives is limited. Herein, we conducted a comprehensive study using an electrochemical approach with a boron doped diamond anode in Na2SO4 electrolyte for the remediation of PFOA common alternatives, i.e., PFBA, GenX, and 6:2 FTCA. The degradability, fluorine recovery, transformation pathway, and contributions from electro-synthesized radicals were investigated. The results indicated the significance of chain length and structure, with shorter chains being harder to break down (PFBA (65.6 ± 5.0%) < GenX (84.9 ± 3.3%) < PFOA (97.9 ± 0.1%) < 6:2 FTCA (99.4 ± 0.0%) within 120 min of electrolysis). The same by-products were observed during the oxidation of both low and high concentrations of parent PFAS (2 and 20 mg L-1), indicating that the fundamental mechanism of PFAS degradation remained consistent. Nevertheless, the ratio of these by-products to the parent PFAS concentration varied which primarily arises from the more rapid PFAS decomposition at lower dosages. For all experiments, the main mechanism of PFAS oxidation was initiated by direct electron transfer at the anode surface. Sulfate radical (SO4•-) also contributed to the oxidation of all PFAS, while hydroxyl radical (•OH) only played a role in the decomposition of 6:2 FTCA. Total fluorine recovery of PFBA, GenX, and 6:2 FTCA were 96.5%, 94.0%, and 76.4% within 240 min. The more complex transformation pathway of 6:2 FTCA could explain its lower fluorine recovery. Detailed decomposition pathways for each PFAS were also proposed through identifying the generated intermediates and fluorine recovery. The proposed pathways were also assessed using 19F Nuclear Magnetic Resonance (NMR) spectroscopy.

PFAS remediation in soil: An evaluation of carbon-based materials for contaminant sequestration

The presence of per- and poly-fluoroalkyl substances (PFAS) in soils is a global concern as these emerging contaminants are highly resistant to degradation and cause adverse effects on human and environmental health at very low concentrations. Sequestering PFAS in soils using carbon-based materials is a low-cost and effective strategy to minimize pollutant bioavailability and exposure, and may offer potential long-term remediation of PFAS in the environment. This paper provides a comprehensive evaluation of current insights on sequestration of PFAS in soil using carbon-based sorbents. Hydrophobic effects originating from fluorinated carbon (C-F) backbone "tail" and electrostatic interactions deriving from functional groups on the molecules' "head" are the two driving forces governing PFAS sorption. Consequently, varying C-F chain lengths and polar functional groups significantly alter PFAS availability and leachability. Furthermore, matrix parameters such as soil organic matter, inorganic minerals, and pH significantly impact PFAS sequestration by sorbent amendments. Materials such as activated carbon, biochar, carbon nanotubes, and their composites are the primary C-based materials used for PFAS adsorption. Importantly, modifying the carbon structural and surface chemistry is essential for increasing the active sorption sites and for strengthening interactions with PFAS. This review evaluates current literature, identifies knowledge gaps in current remediation technologies and addresses future strategies on the sequestration of PFAS in contaminated soil using sustainable novel C-based sorbents.

Occurrence and concentrations of traditional and emerging contaminants in onsite wastewater systems and water supply wells in eastern North Carolina, USA

Onsite wastewater treatment systems (OWTSs) and private wells are commonly used in Eastern North Carolina, USA. Water from private wells is not required to be tested after the initial startup, and thus persons using these wells may experience negative health outcomes if their water is contaminated with waste-related pollutants including bacteria, nitrate or synthetic chemicals such as hexafluoropropylne oxide dimer acid and its ammonium salt (GenX). Water samples from 18 sites with OWTSs and groundwater wells were collected for nitrate, Escherichia coli (E. coli), total coliform, and GenX concentration analyses. Results showed that none of the 18 water supplies were positive for E. coli, nitrate concentrations were all below the maximum contaminant level of 10 mg L-1, and one well had 1 MPN 100 mL-1 of total coliform. However, GenX was detected in wastewater collected from all 18 septic tanks and 22% of the water supplies tested had concentrations that exceeded the health advisory levels for GenX. Water supplies with low concentrations of traditionally tested for pollutants (nitrate, E. coli) may still pose health risks due to elevated concentrations of emerging contaminants like GenX and thus more comprehensive and routine water testing is suggested for this and similar persistent compounds.

Exploring the Potential Link between PFAS Exposure and Endometrial Cancer: A Review of Environmental and Sociodemographic Factors

This exploratory narrative review paper delves into the intricate interplay between per- and polyfluoroalkyl substances (PFAS) exposure, sociodemographic factors, and the influence of stressors in the context of endometrial cancer. PFAS, ubiquitous environmental contaminants notorious for their persistence in the ecosystem, have garnered attention for their potential to disrupt endocrine systems and provoke immune responses. We comprehensively examine the various sources of PFAS exposure, encompassing household items, water, air, and soil, thus shedding light on the multifaceted routes through which individuals encounter these compounds. Furthermore, we explore the influence of sociodemographic factors, such as income, education, occupation, ethnicity/race, and geographical location and their relationship to endometrial cancer risk. We also investigated the role of stress on PFAS exposure and endometrial cancer risk. The results revealed a significant impact of sociodemographic factors on both PFAS levels and endometrial cancer risk. Stress emerged as a notable contributing factor influencing PFAS exposure and the development of endometrial cancer, further emphasizing the importance of stress management practices for overall well-being. By synthesizing evidence from diverse fields, this review underscores the need for interdisciplinary research and targeted interventions to comprehensively address the complex relationship between PFAS, sociodemographic factors, stressors, and endometrial cancer.

Kinetics and proposed mechanisms of hexafluoropropylene oxide dimer acid (GenX) degradation via vacuum-UV (VUV) photolysis and VUV/sulfite processes

We investigated the degradation of hexafluoropropylene oxide dimer acid (GenX) in water via VUV photolysis and VUV/sulfite reactions under nitrogen-saturated conditions. Approximately 35% and 90% of GenX were degraded in 3 h in the VUV photolysis and VUV/sulfite reaction. While GenX removal rate was highest at pH 6 in VUV photolysis, it increased under alkaline pHs, especially at pH 10, in VUV/sulfite reaction. Radical scavenging experiments showed that, while both eaq- and •H contributed to VUV photolysis, eaq- played a significant role and •OH had a negative effect during VUV/sulfite reaction. Two transformation products (TPs) (TFA and PFPrA) were identified in VUV photolysis, whereas five TPs (TFA, PFPrA, TP182, TP348, and TP366) were identified in VUV/sulfite reaction by LCMS/MS and LCQTOF/MS. Defluorination of GenX was observed with the defluorination efficiency after 6 h reaching 17% and 67% in the VUV photolysis and VUV/sulfite reactions, respectively. Degradation mechanism for GenX based on the identified TPs and the theoretical calculation confirmed the susceptibility of GenX to nucleophilic attack. The initial reactions for GenX decomposition were C-C and C-O bond cleavage in both reactions, whereas sulfonation followed by decarboxylation was observed only in the VUV/sulfite reaction. ECOSAR ecotoxicity simulation showed that the toxicities of the TPs were not as harmful as those of GenX.

Concentrations of 45 Per- and Polyfluoroalkyl Substances in North American River Otters (Lontra canadensis) from West Virginia, USA

North American river otters (Lontra canadensis) are top predators in riverine ecosystems and are vulnerable to per- and polyfluoroalkyl substance (PFAS) exposure. Little is known about the magnitude of exposure and tissue distribution of PFAS in river otters. We measured 45 PFAS in various tissues of 42 river otters collected from several watersheds in the state of West Virginia, USA. The median concentrations of ∑All (sum concentration of 45 PFAS) varied among tissues in the following decreasing order: liver (931 ng/g wet weight) > bile > pancreas > lung > kidney > blood > brain > muscle. Perfluoroalkylsulfonates (PFSAs) were the predominant compounds accounting for 58-75% of the total concentrations, followed by perfluoroalkyl carboxylates (PFCAs; 21-35%). 8:2 fluorotelomer sulfonate (8:2 FTS), 10:2 FTS, and 6:2 chlorinated polyfluoroalkyl ether sulfonate were frequently found in the liver (50-90%) and bile (96-100%), whereas hexafluoropropylene oxide dimer acid (HFPO-DA) was rarely found. The hepatic concentrations of ∑All in river otters collected downstream of a fluoropolymer production facility located along the Ohio River were 2-fold higher than those in other watersheds. The median whole body burden of ∑All was calculated to be 1580 μg. PFOS and perfluorooctanoic acid (PFOA) concentrations in whole blood of some river otters exceeded the human toxicity reference values, which warrant further studies.

GenX Disturbs the Indicators of Hepatic Lipid Metabolism Even at Environmental Concentration in Drinking Water via PPARα Signaling Pathways

Hexafluoropropylene oxide dimer acid (HFPO-DA; trade name GenX), as a substitute for perfluorooctanoic acid (PFOA), has been attracting increasing attention. However, its impact and corresponding mechanism on hepatic lipid metabolism are less understood. To investigate the possible mechanisms of GenX for hepatotoxicity, a series of in vivo and in vitro experiments were conducted. In in vivo experiment, male mice were exposed to GenX in drinking water at environmental concentrations (0.1 and 10 μg/L) and high concentrations (1 and 100 mg/L) for 14 weeks. In in vitro experiments, human hepatocellular carcinoma cells (HepG2) were exposed to GenX at 10, 160, and 640 μM for 24 and 48 h. GenX exposure via drinking water resulted in liver damage and disruption of lipid metabolism even at environmental concentrations. The results of triglycerides (TG) and total cholesterol (TC) in this study converged with the results of the population study, for which TG increased in the liver but unchanged in the serum, whereas TC increased in both liver and serum concentrations. KEGG and GO analyses revealed that the hepatotoxicity of GenX was associated with fatty acid transport, synthesis, and oxidation pathways and that Peroxisome Proliferator-Activated Receptor (PPARα) contributed significantly to this process. PPARα inhibitors significantly reduced the expression of CD36, CPT1β, PPARα, SLC27A1, ACOX1, lipid droplets, and TC, suggesting that GenX exerts its toxic effects through PPARα signaling pathway. In general, GenX at environmental concentrations in drinking water causes abnormal lipid metabolism via PPARα signaling pathway.

Association between exposure to per- and perfluoroalkyl substances (PFAS) and reproductive hormones in human: A systematic review and meta-analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) is persistent endocrine disrupting chemicals. Previous evidence suggests that exposure to PFAS is associated with reproductive hormone levels, but the results of relevant studies are inconsistent. The objective of our study is to determine the association between exposure to PFAS and reproductive hormone levels in gender-specific general population.

METHOD

Based on scientific search strategies, we systematically searched PubMed, Web of Science, Embase, Medline, and Scopus to obtain the eligible studies published before January 21, 2023. The quality of the included articles was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias tool. We combined the β coefficient and 95% confidence intervals (CI) using Stata.17 with random-effect model or fixed-effect model. We also performed subgroup analysis, sensitivity analysis, and Begger's and Egger's tests.

RESULTS

Eleven studies involving 7714 participants were included. Meta-analysis showed that PFHxS exposure was positively associated with estradiol (E2) levels in female [β = 0.030, 95% CI: (0.013, 0.046), P = 0.000]. A negative association was found between PFOA [β = -0.012, 95% CI: (-0.023, -0.002), P = 0.017] and PFOS [β = -0.011; 95% CI: (-0.021, -0.000), P = 0.042] exposure with male testosterone (TT) levels. In the subgroup analysis, there were stronger associations in children than in adults. And the high heterogeneity was mainly due to the cross-sectional studies. Publication bias was not found in most of the analyses.

CONCLUSION

Our study showed that PFAS exposure was significantly associated with reproductive hormone levels. Further related studies are needed to identify the association and potential mechanism in the future.

Association of adverse fetal outcomes with placental inflammation after oral gestational exposure to hexafluoropropylene oxide dimer acid (GenX) in Sprague-Dawley rats

Hexafluoropropylene oxide dimer acid (HFPO-DA), known as "GenX" for its trade name, is gradually taking the place of Perfluorooctanoic acid (PFOA). However, there is a poor understanding of the developmental effects of GenX. This study aims to explore whether GenX produces adverse effects on offspring development in Sprague-Dawley (SD) rats and the underlying mechanisms. Pregnant rats were orally administered with GenX (0, 1, 10 and 100 mg/kg/day) from gestational 0.5-19.5 days. Experimental data showed that the exposure to GenX resulted in increased rats' gestational weight gain, whereas both body weight and body length of their fetuses born naturally were significantly reduced. This could contribute to the developmental delays of fetal body weight, body length and tail length from postnatal 1-21 days. Histopathological evaluation of placenta indicated that GenX exposure led to neutrophil infiltration in decidual zone and congestion in labyrinth zone. Moreover, placental proteomics showed changes at the expression levels of the inflammation-related proteins in the Rap1 signaling pathway. In conclusion, gestational exposure to GenX induced fetal intrauterine and extrauterine development retardation in SD rats. Placental inflammation may play a key role in this process through the Rap1 signaling pathway.

Combustion of high-calorific industrial waste in conventional brick kilns: An emerging source of PFAS emissions to agricultural soils

The brick kilns in the South Asian region are widely documented to partially combust high-calorific waste components of synthetic-industrial origin, which contain hazardous constituents, including per- and polyfluoroalkyl substances (PFAS). Correspondingly, these establishments are necessarily built on agricultural land to easily acquire clay by excavating soil horizons, thus making cultivation soils vulnerable to PFAS contaminations. In this pioneering study, the occurrence, distribution profile, traceability and human health risk exposure to forty-four legacy and novel PFAS homologues, including two ultrashort-chain (C2-C3) PFAS, were investigated in agricultural soils around thirty-two conventional brick kilns across three districts of Pakistan. ⅀44PFAS concentrations ranged from 14.3 to 465 ng/g (median: 28.2 ng/g), which were 2 to 70 folds higher than those in background soils, and slightly higher than those reported in agricultural soils in the global literature. The highest occurrence was observed for PFAS alternatives, i.e., 6:2 fluorotelomer sulfonate (6:2 FTSA) (40 %) and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) (4.5 %). A significant positive correlation (p < 0.01) was observed among the concentrations of short-chain perfluoroalkyl acids (C4-C7) and novel PFOS substitutes, implying their origin from common sources. Furthermore, ultrashort-chain and short-chain perfluorocarboxylic acids (PFCA) (89 %) and perfluorosulfonic acids (PFSA) (63 %) dominated over long-chain's PFCA (11 %) and PFSA (37 %), respectively. The estimated daily intake to children exposed in surrounding inhabited communities, at 95th percentile concentrations was found to be approaching the European tolerable daily intake limit of 0.63 ng/kg bw/day. Therefore, the brick manufacturing industry is identified as a novel source of PFAS in the adjacent environment and for residents. This suggests the need for further investigations to elucidate the origin of emerging contaminants in the waste streams of the region to safeguard ecological integrity.

Per- and polyfluoroalkyl ether acids in well water and blood serum from private well users residing by a fluorochemical facility near Fayetteville, North Carolina

BACKGROUND

A fluorochemical facility near Fayetteville, North Carolina, emitted per- and polyfluoroalkyl ether acids (PFEAs), a subgroup of per- and polyfluoroalkyl substances (PFAS), to air.

OBJECTIVE

Analyze PFAS in private wells near the facility and in blood from well users to assess relationships between PFEA levels in water and serum.

METHODS

In 2019, we recruited private well users into the GenX Exposure Study and collected well water and blood samples. We targeted 26 PFAS (11 PFEAs) in water and 27 PFAS (9 PFEAs) in serum using liquid chromatography-mass spectrometry. We used regression modeling to explore relationships between water and serum PFAS. For the only PFEA detected frequently in water and serum, Nafion byproduct 2, we used generalized estimating equation (GEE) models to assess well water exposure metrics and then adjusted for covariates that may influence Nafion byproduct 2 serum concentrations.

RESULTS

We enrolled 153 participants ages 6 and older (median = 56 years) using 84 private wells. Most wells (74%) had ≥6 detectable PFEAs; median ∑PFEAs was 842 ng/L (interquartile range = 197-1760 ng/L). Low molecular weight PFEAs (PMPA, HFPO-DA [GenX], PEPA, PFO2HxA) were frequently detected in well water, had the highest median concentrations, but were not detectable in serum. Nafion byproduct 2 was detected in 73% of wells (median = 14 ng/L) and 56% of serum samples (median = 0.2 ng/mL). Cumulative dose (well concentration × duration at address) was positively associated with Nafion byproduct 2 serum levels and explained the most variability (10%). In the adjusted model, cumulative dose was associated with higher Nafion byproduct 2 serum levels while time outside the home was associated with lower levels.

IMPACT

PFAS are a large class of synthetic, fluorinated chemicals. Fluorochemical facilities are important sources of environmental PFAS contamination globally. The fluorochemical industry is producing derivatives of perfluoroalkyl acids, including per- and polyfluoroalkyl ether acids (PFEAs). PFEAs have been detected in various environmental samples but information on PFEA-exposed populations is limited. While serum biomonitoring is often used for PFAS exposure assessment, serum biomarkers were not good measures of long-term exposure to low molecular weight PFEAs in a private well community. Environmental measurements and other approaches besides serum monitoring will be needed to better characterize PFEA exposure.

Nontarget Identification of Novel Per- and Polyfluoroalkyl Substances (PFAS) in Soils from an Oil Refinery in Southwestern China: A Combined Approach with TOP Assay

Oil refinery activity can be an emission source of perfluoroalkyl and polyfluoroalkyl substances (PFAS) to the environment, while the contamination profiles in soils remain unknown. This study investigated 44 target PFAS in soil samples collected from an oil refinery in Southeastern China, identified novel PFAS, and characterized their behaviors by assessing their changes before and after employing advanced oxidation using a combination of nontarget analysis and a total oxidizable precursor (TOP) assay. Thirty-four target PFAS were detected in soil samples. Trifluoroacetic acid (TFA) and hexafluoropropylene oxide dimer acid (HFPO-DA) were the dominant PFAS. Twenty-three novel PFAS of 14 classes were identified, including 8 precursors, 11 products, and 4 stable PFAS characterized by the TOP assay. Particularly, three per-/polyfluorinated alcohols were identified for the first time, and hexafluoroisopropanol (HFIP) quantified up to 657 ng/g dw is a novel precursor for TFA. Bistriflimide (NTf2) potentially associated with an oil refinery was also reported for the first time in the soil samples. This study highlighted the advantage of embedding the TOP assay in nontarget analysis to reveal not only the presence of unknown PFAS but also their roles in environmental processes. Overall, this approach provides an efficient way to uncover contamination profiles of PFAS especially in source-impacted areas.

Predictions of PFAS regional-scale atmospheric deposition and ambient air exposure

Per- and polyfluoroalkyl substances (PFAS) are a large class of human-made compounds that have contaminated the global environment. One environmental entry point for PFAS is via atmospheric emission. Air releases can impact human health through multiple routes, including direct inhalation and contamination of drinking water following air deposition. In this work, we convert the reference dose (RfD) underlying the United States Environmental Protection Agency's GenX drinking water Health Advisory to an inhalation screening level and compare to predicted PFAS and GenX air concentrations from a fluorochemical manufacturing facility in Eastern North Carolina. We find that the area around the facility experiences ~15 days per year of GenX concentrations above the inhalation screening level we derive. We investigate the sensitivity of model predictions to assumptions regarding model spatial resolution, emissions temporal profiles, and knowledge of air emission chemical composition. Decreasing the chemical specificity of PFAS emissions has the largest impact on deposition predictions with domain-wide total deposition varying by as much as 250 % for total PFAS. However, predicted domain-wide mean and median air concentrations varied by <18 % over all scenarios tested for total PFAS. Other model features like emission temporal variability and model spatial resolution had weaker impacts on predicted PFAS deposition.

Dose Response, Dosimetric, and Metabolic Evaluations of Replacement PFAS Perfluoro-(2,5,8-trimethyl-3,6,9-trioxadodecanoic) Acid (HFPO-TeA)

Few studies are available on the environmental and toxicological effects of perfluoroalkyl ether carboxylic acids (PFECAs), such as GenX, which are replacing legacy PFAS in manufacturing processes. To collect initial data on the toxicity and toxicokinetics of a longer-chain PFECA, male and female Sprague Dawley rats were exposed to perfluoro-(2,5,8-trimethyl-3,6,9-trioxadodecanoic) acid (HFPO-TeA) by oral gavage for five days over multiple dose levels (0.3-335.2 mg/kg/day). Clinically, we observed mortality at doses >17 mg/kg/day and body weight changes at doses ≤17 mg/kg/day. For the 17 mg/kg/day dose level, T3 and T4 thyroid hormone concentrations were significantly decreased (p < 0.05) from controls and HFPO-TeA plasma concentrations were significantly different between sexes. Non-targeted analysis of plasma and in vitro hepatocyte assay extractions revealed the presence of another GenX oligomer, perfluoro-(2,5-dimethyl-3,6-dioxanonanoic) acid (HFPO-TA). In vitro to in vivo extrapolation (IVIVE) parameterized with in vitro toxicokinetic data predicted steady-state blood concentrations that were within seven-fold of those observed in the in vivo study, demonstrating reasonable predictivity. The evidence of thyroid hormone dysregulation, sex-based differences in clinical results and dosimetry, and IVIVE predictions presented here suggest that the replacement PFECA HFPO-TeA induces a complex and toxic exposure response in rodents.

Influence of dietary bioactive compounds on the bioavailability and excretion of PFOA and its alternative HFPO-TA: Mechanism exploration

Oral ingestion is considered an important route of human exposure to perfluorooctanoic acid (PFOA) and its alternative hexafluoropropylene oxide trimer acid (HFPO-TA). Bioactive compounds are widely used as dietary supplements and food additives. However, little is known about the influence of dietary bioactive compounds on the bioavailability of PFOA and HFPO-TA. Here, three dietary bioactive compounds, β-carotene, quercetin and curcumin, were selected to study their influence on the relative bioavailability (RBA) of PFOA and HFPO-TA in soil using a mouse model. Compared to the control group (68.7 ± 6.27 %), quercetin and curcumin at medium and high doses (20 and 100 mg/kg/d) significantly (p < 0.05) decreased PFOA RBA to 55.2 ± 4.85-56.4 ± 4.57 % and 48.3 ± 5.49-48.6 ± 5.44 %, respectively. Mechanism study showed that medium- and high-dose quercetin as well as high-dose curcumin increased urinary excretion of PFOA by 33.6-35.6 % and 32.2 % through upregulating renal expression of multidrug resistance protein 2 (Mrp2) (1.52-1.63 folds) and Mrp4 (1.26-1.53 folds), thereby reducing PFOA accumulation. In PFOA-treated groups, quercetin at medium and high doses dramatically downregulated the hepatic expression of organic anion transport polypeptides (Oatp1a6, Oatp1b2), organic anion transport proteins (Oat1, Oat2), and fatty acid binding proteins (FABP4, FABP12), while curcumin at medium and high doses inhibited the hepatic expression of Oatp1a6, Oat1 and Oat2. These downregulated genes may reduce the transport of PFOA from blood to liver, and in turn decrease the PFOA RBA. However, β-carotene, quercetin and curcumin exhibited no significant effect on RBA and excretion of HFPO-TA (p > 0.05). This indicated the different absorption mechanisms between PFOA and HFPO-TA, and further research is warranted. This study provided a novel perspective for establishing environmentally friendly ways to reduce health hazards from per- and polyfluoroalkyl substances (PFASs).

Investigation of Sources of Fluorinated Compounds in Private Water Supplies in an Oil and Gas-Producing Region of Northern West Virginia

Per- and polyfluoroalkyl substances (PFASs) are a class of toxic organic compounds that have been widely used in consumer applications and industrial activities, including oil and gas production. We measured PFAS concentrations in 45 private wells and 8 surface water sources in the oil and gas-producing Doddridge, Marshall, Ritchie, Tyler, and Wetzel Counties of northern West Virginia and investigated relationships between potential PFAS sources and drinking water receptors. All surface water samples and 60% of the water wells sampled contained quantifiable levels of at least one targeted PFAS compound, and four wells (8%) had concentrations above the proposed maximum contaminant level (MCL) for perfluorooctanoic acid (PFOA). Individual concentrations of PFOA and perfluorobutanesulfonic acid exceeded those measured in finished public water supplies. Total targeted PFAS concentrations ranged from nondetect to 36.8 ng/L, with surface water concentrations averaging 4-fold greater than groundwater. Semiquantitative, nontargeted analysis showed concentrations of emergent PFAS that were potentially higher than targeted PFAS. Results from a multivariate latent variable hierarchical Bayesian model were combined with insights from analyses of groundwater chemistry, topographic characteristics, and proximity to potential PFAS point sources to elucidate predictors of PFAS concentrations in private wells. Model results reveal (i) an increased vulnerability to contamination in upland recharge zones, (ii) geochemical controls on PFAS transport likely driven by adsorption, and (iii) possible influence from nearby point sources.

Target and nontarget analysis of per- and polyfluoroalkyl substances in surface water, groundwater and sediments of three typical fluorochemical industrial parks in China

The objectives of this study were to identify both legacy and emerging per- and polyfluoroalkyl substances (PFAS) from three typical fluoridated industrial parks (FIPs) in China, and to assess their environmental occurrence and fate. Complementary suspect target and nontarget screening were implemented, and a total of 111 emerging PFAS were identified. Based on the multi-mass scale analysis, 25 emerging PFAS were identified for the first time, including 24 per- and polyfluoroalkyl ether carboxylic acids (PFECAs) and 1 ultra-short chlorinated perfluoroalkyl carboxylic acids (Cl-PFCAs, C2), with a maximum percentage of 48.2 % in nontarget PFAS (exclude target PFAS). The composition of PFAS identified in different media was influenced by functional groups, carbon chain length, substituents and ether bond insertion, with poly-hydrogen substituted being preferably in water and a more diverse pattern of PFECAs in sediments. The patterns of PFAS homologs revealed distinct differences among the three typical FIPs in the shift of PFAS production patterns. The C4-PFAS and short-chain carboxylic acids (≤C6) were the main PFAS in the Fuxin and Changshu, respectively. In contrast, perfluorooctanoic acid (PFOA, C8) remained dominant in Zibo, and the highest point concentrations in water and sediment were up to 706 µg/L and 553 µg/g, respectively.

The wide presence of fluorinated compounds in common chemical products and the environment: a review

The C-F bonds, due to their many unique features, have been incorporated into numerous compounds in countless products and applications. These fluorinated compounds eventually are disposed of and released into the environment through different pathways. In this review, we analyzed the occurrence of these fluorinated compounds in seven types of products (i.e., refrigerants/propellants, aqueous film-forming foam, cosmetics, food packaging, agrochemicals, pharmaceuticals, coating materials) and discussed their fate in the environment. This is followed by describing the quantity of fluorinated compounds from each source based on available data. Total on- and off-site disposal or other releases of 536 fluorinated compounds in 2021 were analyzed using the data sourced from the U.S. EPA Toxics Release Inventory (TRI). Among the chemicals examined, chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) were the primary contributors in terms of total mass. Upon examining the seven sources of fluorinated compounds, it became evident that additional contributors are also responsible for the presence of organofluorine compounds in the environment. Although various toxic degradation products of fluorinated compounds could form in the environment, trifluoroacetic acid (TFA) was specifically highlighted in this review given the fact that it is a common dead-end degradation product of > 1 million chemicals. This paper ended with a discussion of several questions raised from this study. The path forward was elaborated as well for the purpose of protecting the environment and human health.

Perfluorooctanoic Acid Promotes Recruitment and Exocytosis of Rodlet Cells in the Renal Hematopoietic Tissue of Common Carp

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants, with perfluorooctanoic acid (PFOA) being a prominent member. PFOA poses a risk to aquatic ecosystems and human health due to its presence in water, environmental persistence, and bioaccumulation. Since rodlet cells (RCs) have emerged as potential biomarkers for chemical stressors, this study aimed to investigate the effects of sub-chronic PFOA exposure on RCs in the renal hematopoietic tissue of common carp. Three groups of fish were used: an unexposed control group and two groups exposed to environmentally relevant (200 ng L-1) and elevated (2 mg L-1) PFOA concentrations. Light and transmission electron microscopy were employed to assess RCs' distribution patterns and exocytosis, while biometry quantified RCs in the hematopoietic tissue. The results showed that, even at environmentally relevant concentrations, PFOA significantly influenced RCs' distribution patterns, leading to increased occurrence and cluster formation, as well as heightened exocytosis activity. This research highlights PFOA's immunotoxicity in fish and suggests the potential of RCs as sentinel cells in the immunological response to environmental contaminants. These findings enhance our understanding of PFAS toxicity and emphasise the importance of monitoring their impact on fish as representative vertebrates and reliable animal models.

Algae-Enhanced Electrospun Polyacrylonitrile Nanofibrous Membrane for High-Performance Short-Chain PFAS Remediation from Water

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.

Evidence of large-scale deposition of airborne emissions of per- and polyfluoroalkyl substances (PFASs) near a fluoropolymer production plant in an urban area

Airborne emissions of per- and polyfluoroalkyl substances (PFASs) from fluoropolymer manufacturing facilities-especially those producing polyvinylidene (PVDF)-have rarely been investigated. Once PFASs are released into the air from the facility stacks, they settle in the surrounding environment, contaminating all surfaces. Human beings living in close proximity to these facilities can be exposed through air inhalation and ingestion of contaminated vegetables, drinking water or dust. In this study, we collected nine surface soil and five outdoor settled dust samples within 200 m of the fence line of a PVDF and fluoroelastomer production site near Lyon (France). Samples were collected in an urban area including a sports field. High concentrations of long-chain perfluoroalkyl carboxylic acids (PFCAs) (C ≥ 9) were found at sampling points downwind of the facility. Perfluoroundecanoic acid (PFUnDA) was the predominant PFAS in surface soil (12-245 ng/g dw), whereas perfluorotridecanoic acid (PFTrDA) was in outdoor dust (<0.5-59 ng/g dw). The PFAS profiles observed in soil and dust samples very likely originate from the processing aids used for PVDF and fluoroelastomer production. To our knowledge, long-chain PFCA concentrations as high as reported herein have never been found outside the perimeter fencing of a fluoropolymer plant. PFAS concentrations in other environmental compartments (such as air, vegetables or groundwater) should be monitored to assess all potential pathways to exposure of nearby residents before carrying out human biomonitoring.

PFAS soil concentrations surrounding a hazardous waste incinerator in East Liverpool, Ohio, an environmental justice community

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic compounds widely used in industrial and consumer products. While PFAS provide product durability, these chemicals are ubiquitous, persistent, bioaccumulative, and toxic. These characteristics make the ultimate disposal of PFAS a challenge. One current disposal method is incineration; however, little research has been conducted on the safety and effectiveness of PFAS incineration. The characteristics of communities with hazardous waste incinerators that have received PFAS shipments indicate that more individuals with lower incomes and individuals with less education than the US average are at higher risk of exposure, which presents important environmental justice and health equity concerns of PFAS incineration. Situated in eastern Ohio, East Liverpool is an Appalachian community that is home to a large hazardous-waste incinerator, operated by Heritage WTI, that began accepting PFAS in 2019. Residents are concerned that the disposal lacks the research necessary to assure safety for the residents. Due to both community interest and data gaps regarding PFAS incineration, our research team conducted a pilot study to examine the distribution and concentration of PFAS in soil samples surrounding the incinerator. All 35 soil samples had measurable amounts of PFAS including perfluorobutanesulfonic acid (PFBS), perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and hexafluoropropylene oxide dimer acid (HFPO-DA)/GenX. PFOS was measured in the majority of soil samples (97%) with a range of 50-8,300 ng/kg. PFOA was measured in 94% of soil samples with a range of 51 ng/kg to 1300 ng/kg. HFPO-DA/GenX was measurable in 12 soil samples with concentrations of ranging from 150 ng/kg to 1500 ng/kg. Further research on PFAS disposal will advance knowledge and action related to regulatory requirements and exposure prevention, ultimately improving individual and community protections and health equity.

Environmental and health impacts of PFAS: Sources, distribution and sustainable management in North Carolina (USA)

Poly- and perfluoroalkyl substances (PFAS) are a class of manufactured chemicals that have recently attracted a great deal of attention from environmental regulators and the general public because of their high prevalence, resistance to degradation, and potential toxicity. This review summarizes the current state of PFAS and its effects on the environment of North Carolina, USA. Specific emphasis has been placed to identify i) the sources of PFAS in North Carolina ii) distribution of PFAS in different environmental segments of North Carolina, including surface water, groundwater, air, and sediment iii) drinking water contamination iv) impact of PFAS on human health v) PFAS accumulation in fish and other biota vi) status of PFAS removal from drinking water and finally vi) socioeconomic impact of PFAS uncertainties. Continuous discharges of PFAS occur in the North Carolina environment from direct and indirect sources, including manufacturing sites, firefighting foam, waste disposal and treatment plants, landfill leachate, and industrial emissions. PFAS are widespread in many environmental segments of North Carolina. They are more likely to be detected in surface and groundwater sediments and can enter aquatic bodies through direct discharge and wet and dry deposition of emissions. Eventually, some adverse effects of PFAS have already been reported in North Carolina residents who could have been exposed to the chemicals through contaminated drinking water. Furthermore, PFAS were also found in blood samples from fish and alligators. PFAS were confirmed to be present in water, sediment, organic compounds, and aquatic species at all levels of the food web. However, there is still a substantial amount of work to be done to understand the actual contamination by PFAS in North Carolina comprehensively.

Environmental Fate of Cl-PFPECAs: Accumulation of Novel and Legacy Perfluoroalkyl Compounds in Real-World Vegetation and Subsoils

Per- and polyfluoroalkyl substances (PFAS) are globally distributed and potentially toxic compounds. We report accumulation of chloroperfluoropolyethercarboxylates (Cl-PFPECAs) and perfluorocarboxylates (PFCAs) in vegetation and subsoils in New Jersey. Lower molecular weight Cl-PFPECAs, containing 7-10 fluorinated carbons, and PFCAs containing 3-6 fluorinated carbons were enriched in vegetation relative to surface soils. Subsoils were dominated by lower molecular weight Cl-PFPECAs, a divergence from surface soils. Contrastingly, PFCA homologue profiles in subsoils were similar to surface soils, likely reflecting temporal-use patterns. Accumulation factors (AFs) for vegetation and subsoils decreased with increasing CF2, 6-13 for vegetation and 8-13 in subsoils. In vegetation, for PFCAs having CF2 = 3-6, AFs diminished with increasing CF2 as a more sensitive function than for longer chains. Considering that PFAS manufacturing has transitioned from long-chain chemistry to short-chain, this elevated vegetative accumulation of short-chain PFAS suggests the potential for unanticipated PFAS exposure levels globally in human and/or wildlife populations. This inverse relationship between AFs and CF2-count in terrestrial vegetation is opposite the positive relationship reported in aquatic vegetation suggesting aquatic food webs may be preferentially enriched in long-chain PFAS. AFs normalized to soil-water concentrations increased with chain length for CF2 = 6-13 in vegetation but remained inversely related to chain length for CF2 = 3-6, reflecting a fundamental change in vegetation affinity for short chains compared to long.

A review on simultaneous heavy metal removal and organo-contaminants degradation by potential microbes: Current findings and future outlook

Industrial processes result in the production of heavy metals, dyes, pesticides, polyaromatic hydrocarbons (PAHs), pharmaceuticals, micropollutants, and PFAS (per- and polyfluorinated substances). Heavy metals are currently a significant problem in drinking water and other natural water bodies, including soil, which has an adverse impact on the environment as a whole. The heavy metal is highly poisonous, carcinogenic, mutagenic, and teratogenic to humans as well as other animals. Multiple polluted sites, including terrestrial and aquatic ecosystems, have been observed to co-occur with heavy metals and organo-pollutants. Pesticides and heavy metals can be degraded and removed concurrently from various metals and pesticide-contaminated matrixes due to microbial processes that include a variety of bacteria, both aerobic and anaerobic, as well as fungi. Numerous studies have examined the removal of heavy metals and organic-pollutants from different types of systems, but none of them have addressed the removal of these co-occurring heavy metals and organic pollutants and the use of microbes to do so. Therefore, the main focus of this review is on the recent developments in the concurrent microbial degradation of organo-pollutants and heavy metal removal. The limitations related to the simultaneous removal and degradation of heavy metals and organo-pollutant pollutants have also been taken into account.

Pre-differentiation GenX exposure induced neurotoxicity in human dopaminergic-like neurons

GenX, also known as hexafluoropropylene oxide dimer acid (HFPO) was introduced as a safer alternative to perfluorooctanoic acid (PFOA) in 2009. After nearly two decades of applications there are increasing safety concerns about GenX due to its association with various organ damages. Few studies, however, have systematically assessed the molecular neurotoxicity of low-dose GenX exposure. Here, we evaluated the effects of pre-differentiation exposure of GenX on dopaminergic (DA) -like neurons using SH-SY5Y cell line; and assessed changes in epigenome, mitochondrion, and neuronal characteristics. Low dose GenX exposure at 0.4 and 4 μg/L prior to differentiation induces persistent changes in nuclear morphology and chromatin arrangements, manifested specifically in the facultative repressive marker H3K27me3. We also observed impaired neuronal network, increased calcium activity along with alterations in Tyrosine hydroxylase (TH) and α-Synuclein after prior exposure to GenX. Collectively, our results identified neurotoxicity of low-dose GenX exposure in human DA-like neurons following a developmental exposure scheme. The observed changes in neuronal characteristics suggest GenX as a potential neurotoxin and risk factor for Parkinson's disease.

Comprehensive target analysis and TOP assay of per- and polyfluoroalkyl substances (PFAS) in wild boar livers indicate contamination hot-spots in the environment

The suitability of wild boar liver as a bioindicator of per- and polyfluoroalkyl substances (PFAS) in the terrestrial environment was investigated. Samples from 50 animals in three different areas associated with (1) contaminated paper sludges distributed on arable land (PS), (2) industrial emissions of PFAS (IE) and (3) background contamination (BC) were analyzed for 66 PFAS, including legacy PFAS, novel substitutes and precursors of perfluoroalkyl acids (PFAAs). Additionally, the Total Oxidizable Precursor (TOP) assay was performed to determine the formation potential of PFAAs from precursors. In total, 31 PFAS were detected with site-specific contamination profiles. PFAS concentrations in livers from area PS and IE (567 and 944 μg kg^-1 wet weight, respectively) were multiple times higher than from area BC (120 μg kg^-1). The dominating PFAS were the legacy compounds perfluorooctane sulfonic acid (PFOS) in areas PS and BC (426 and 82 μg kg^-1, respectively) and perfluorooctanoic acid (PFOA) in area IE (650 μg kg^-1). In area IE, the compounds 4,8-dioxa-3H-perfluorononanoic acid (DONA) and hexafluoropropylene oxide dimer acid (HFPO-DA) - which are used as substitutes for PFOA - were determined at 15 and 0.29 μg kg^-1, respectively. The formation potential of PFAAs was highest in area PS, but generally lower than the contamination with PFAAs. The pattern of perfluoroalkyl carboxylic acids (PFCAs) in wild boar liver reflects the contamination of the local soil at the two hot-spot areas IE and PS. This first comparison of PFAS contamination between wild boars and soil suggests that wild boar livers are suitable bioindicators for PFAS contamination in the terrestrial environment. Moreover, in terrestrial samples from area IE, legacy PFAS were found to be retained for a longer period as compared to riverine samples (suspended particulate matter and chub filet).

Tubing material considerably affects measurement delays of gas-phase oxygenated per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants associated with negative health impacts. Assessments of tubing-related measurement bias for volatile PFAS are lacking, as gas-wall interactions with tubing can delay quantification of gas-phase analytes. We use online iodide chemical ionization mass spectrometry measurements to characterize tubing delays for three gas-phase oxygenated PFAS - 4:2 fluorotelomer alcohol (4:2 FTOH), perfluorobutanoic acid (PFBA), and hexafluoropropylene oxide dimer acid (HFPO-DA). Perfluoroalkoxy alkane and high-density polyethylene tubing yielded relatively short absorptive measurement delays, with no clear dependence on tubing temperature or sampled humidity. Sampling through stainless steel tubing led to prolonged measurement delays due to reversible adsorption of PFAS to the tubing surface, with strong dependence on tubing temperature and sample humidification. Silcosteel tubing afforded shorter measurement delays than stainless steel due to diminished surface adsorption of PFAS. Characterizing and mitigating these tubing delays is crucial for reliable quantification of airborne PFAS.Implications: Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants. Many PFAS are sufficiently volatile to exist as airborne pollutants. Measurements and quantification of airborne PFAS can be biased from material-dependent gas-wall interactions with sampling inlet tubing. Thus, characterizing these gas-wall interactions are crucial for reliably investigating emissions, environmental transport, and fates of airborne PFAS.

The use of gas chromatography - high resolution mass spectrometry for suspect screening and non-targeted analysis of per- and polyfluoroalkyl substances

This study is a workflow development for the analysis, identification, and categorization of per- and polyfluoroalkyl substances (PFAS) using gas chromatography-high resolution mass spectrometry (GC-HRMS) with non-targeted analysis (NTA) and suspect screening techniques. The behavior of various PFAS in a GC-HRMS was studied with regards to retention indices, ionization susceptibility, fragmentation patterns, etc. A custom PFAS database was constructed from 141 diverse PFAS. The database contains mass spectra from electron ionization (EI) mode, as well as MS and MS/MS spectra from positive and negative chemical ionization (PCI and NCI, respectively) modes. Common fragments of PFAS were identified across a diverse set of 141 PFAS analyzed. A workflow for suspect screening of PFAS and partially fluorinated products of incomplete combustion/destruction (PICs/PIDs) was developed which utilized both the custom PFAS database and external databases. PFAS and other fluorinated compounds were identified in both a challenge sample (designed to test the identification workflow) and incineration samples suspected to contain PFAS and fluorinated PICs/PIDs. The challenge sample resulted in a 100% true positive rate (TPR) for PFAS which were present in the custom PFAS database. Several fluorinated species were tentatively identified in the incineration samples using the developed workflow.

High density polyethylene (HDPE) and thermoplastic polyurethane (TPU) wristbands as personal passive samplers monitoring per- and polyfluoroalkyl substances (PFASs) exposure to postgraduate students

Per- and polyfluoroalkyl substances (PFASs) present adverse effects for human health, which result in strong needs for reliable tools monitoring personal exposure to PFASs. This study manufactured two wristbands of high density polyethylene (HDPE) and thermoplastic polyurethane (TPU), and used the wristbands to monitor PFASs personal exposure. The analytical method was developed to measure 32 PFASs in the paired HDPE and TPU wristbands worn by 60 postgraduates. Twenty-nine of 32 PFASs were detected and hexafluoropropylene oxide dimer acid (HFPO-DA) was predominant individual PFASs with median concentrations of 337 and 554 pg/g for HDPE and TPU wristbands respectively. The gender and grade of students had moderate effects on PFASs distribution in the wristbands. Higher PFASs levels were determined in the two wristbands worn by the male students compared to the females, and the greatest PFASs concentration was observed in the wristbands worn by the first-year postgraduates, follow by second- and third-year postgraduates. Additionally, significant correlations between paired HDPE and TPU wristbands were observed for perfluorobutanoic acid (PFBA), perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonic acid (PFOS), and HFPO-DA. These results suggest that HDPE and TPU wristbands can be used as effective tools for monitoring personal PFAS exposure.

Occurrence of perfluoroalkyl substances in the environment compartments near a mega fluorochemical industry: Implication of specific behaviors and emission estimation

With the stringent restrictions on long-chain per- and polyfluoroalkyl substances (PFASs), ether-PFASs are being widely used as alternatives. We estimated that the mega fluorochemical industrial park (FIP) in Shandong, China, had emitted a maximum of 5040 kg and 1026 kg of hexafluoropropylene oxides (HFPOs), and 7560 kg and 1890 kg of perfluorooctanoic acid (PFOA) to water and air during 2021. In the surface water, groundwater, outdoor dust, soil, tree leaf and bark collected in the vicinity of the FIP, PFOA was predominant, followed by HFPOs. The much higher percentage of HFPO dimer acid (HFPO-DA) in groundwater than in surface water verified that this compound was more mobile in porous media. The strong correlations between the main PFASs in outdoor dust and surface soil suggested that the soil PFASs were mainly derived from air deposition, particularly for HFPO trimer acid (HFPO-TA), which has a stronger binding affinity with particles than PFOA. High percentage of the hydroxylated product of 6:2 polyfluorinated ether sulfonic acid was observed in groundwater, implying reductive dechlorination might occur in groundwater. Strong correlations between PFASs in outdoor dust and those in tree leaf and bark magnified that tree could serve as a sampler to effectively monitor airborne PFASs. This study provides the first line of information about the discharge, transport, and fate of novel ether-PFASs in the multiple environmental media near a point source.

Per- and polyfluoroalkyl substances (PFAS) exposure through munitions in the Russia-Ukraine conflict

Considered contaminants of emerging concern, per- and polyfluoroalkyl substances (PFAS) are a class of toxic, manufactured chemicals found in commercial and consumer products such as nonstick cookware, food packaging, and firefighting foams. Human exposure to PFAS through inhalation and ingestion can cause a variety of harmful effects and negative health outcomes. Per- and polyfluoroalkyl substances possess high polarity and chemical stability, enabling them to resist degradation in most environmental conditions. These characteristics allow PFAS to be mobile in soil, air, and water, and bioaccumulate in living organisms. Due to their thermally resistant chemical properties, PFAS are used as binders in polymer-bonded explosives (PBX) and in various components of munitions. Thus, when munitions are detonated, PFAS are released into the environment as aerosols and can deposit in the soil, surface water, or biota. Air emission modeling suggests that ground-level and airborne detonation of munitions can increase PFAS deposition both locally and long range. Further, if industrial facilities with PFAS are damaged or destroyed, there is greater potential for environmental degradation from increased release of PFAS into the environment. As a consequence of their persistent nature, PFAS can remain in an environment long after armed conflict, indirectly affecting ecosystems, food sources, and human health. The toxic contamination from munitions could present a greater hazard to a larger population over time than acute detonation events. This article discusses methods for estimating war-related damage from PFAS by exploring predictive modeling approaches and postwar ground validation techniques. Integr Environ Assess Manag 2023;19:376-381. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Effects of perfluorooctanoic acid on endoplasmic reticulum stress and lipid metabolism-related genes in human pancreatic cells

Perfluorooctanoic acid (PFOA) is environmentally persistent and has been classified by The International Cancer Research Agency (IARC) as a possible human pancreatic carcinogen. In this study, the epigenetic alteration, the changes in the expression levels of endoplasmic reticulum stress-related and metabolism-related genes, as well as DNA methyltransferase expression were investigated using RT-PCR and ELISA assays. PFOA induced a significant increase in the methylation ratio (5-mC%), impacted DNA methylation maintenance gene expression and decreased lipid metabolism-related genes except for PPARγ (≥ 13-fold increase). While PFOA induced the expression of ATF4 (≥ 5.41-folds), CHOP (≥ 5.41-folds) genes, it inhibited the expression of ATF6 (≥ 67.2%), GRP78 (≥ 64.3%), Elf2α (≥ 95.8%), IRE1 (≥ 95.5%), and PERK (≥ 91.7%) genes. It is thought that epigenetic mechanisms together with disruption in the glucose-lipid metabolism and changes in endoplasmic reticulum stress-related genes may play a key role in PFOA-induced pancreatic toxicity.

Toxicity assessment of hexafluoropropylene oxide-dimer acid on morphology, heart physiology, and gene expression during zebrafish (Danio rerio) development

Hexafluoropropylene oxide-dimer acid (HFPO-DA) is one of the emerging replacements for the "forever" carcinogenic and toxic long-chain PFAS. HFPO-DA is a polymerization aid used for manufacturing fluoropolymers, whose global distribution and undetermined toxic properties are a concern regarding human and ecological health. To assess embryotoxic potential, zebrafish embryos were exposed to HFPO-DA at concentrations of 0.5-20,000 mg/L at 24-, 48-, and 72-h post-fertilization (hpf). Heart rate increased significantly in embryos exposed to 2 mg/L and 10 mg/L HFPO-DA across all time points. Spinal deformities and edema phenotypes were evident among embryos exposed to 1000-16,000 mg/L HFPO-DA at 72 hpf. A median lethal concentration (LC₅₀) was derived as 7651 mg/L at 72 hpf. Shallow RNA sequencing analysis of 9465 transcripts identified 38 consistently differentially expressed genes at 0.5 mg/L, 1 mg/L, 2 mg/L, and 10 mg/L HFPO-DA exposures. Notably, seven downregulated genes were associated with visual response, and seven upregulated genes were expressed in or regulated the cardiovascular system. This study identifies biological targets and molecular pathways affected during animal development by an emerging, potentially problematic, and ubiquitous industrial chemical.

Tissue-specific accumulation, depuration, and effects of perfluorooctanoic acid on fish: Influences of aqueous pH and sex

Perfluorooctanoic acid (PFOA) is widely distributed in nature, particularly in aquatic environments. Its bioaccumulation and toxicity in aquatic organisms can be affected by both the chemical status of PFOA in water and the physiology of the organism. However, research on the patterns of these effects is scarce. In this study, we investigated the influence of aqueous pH (pH 6, acidic; pH 7.5, neutral; pH 9, basic) and fish sex on PFOA uptake, clearance, and biochemical effects in crucian carp (C. auratus) using flow-through exposure. In the 17-d kinetic experiment, PFOA bioaccumulation adhered to a uniform first-order model in which PFOA uptake rates from water to blood and liver in acidic conditions were faster than those in other conditions, indicating possible acidic pH influence on PFOA uptake. PFOA clearance rates in these compartments of males were slower than in females, which was attributed to the notably stronger expression of Oat2 (organic anion transporter 2, responsible for reabsorption) in the kidneys of males. Similar responses were observed for peroxisome proliferation-related biomarkers at different pH levels and in different sexes. These biochemical responses were driven by the internal concentrations of PFOA. The inhibition acetylcholinesterase activity in the fish brain was closely linked to changes in P-glycoprotein content, demonstrating a protective relationship. Collectively, an aqueous pH lower than 7.5 might affect the uptake of PFOA by fish. The clearance discrepancies between the sexes highlight the importance of anion carriers for ionizable organic compounds in aquatic organisms.

PFAS on atmospheric aerosol particles: a review

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants of concern to human health. These synthetic chemicals are in widespread use for consumer products, firefighting foams, and industrial applications. They have been detected all over the globe, including at remote locations distant from any possible point sources. One mechanism for long-range transport of PFAS is through sorption to aerosol particles in the atmosphere. PFAS can be transferred from the sea surface to sea spray aerosol particles through wave breaking and bubble bursting, and PFAS emitted to the atmosphere in the gas phase can sorb to particulate matter through gas-particle partitioning. Here we present a comprehensive review of global measurements of PFAS on ambient particulate matter dating back to the first reports from the early 2000s. We summarize findings for the historically important C8 species, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), including detection of isomers and size-segregated measurements, as well as studies of newer and emerging PFAS. We conclude that long-term monitoring of PFAS on particulate matter should be expanded to include more measurement sites in under-sampled regions of the world and that further non-targeted work to identify novel PFAS structures is needed as PFAS manufacturing and regulations continue to evolve.

Removal and destruction of perfluoroalkyl ether carboxylic acids (PFECAs) in an anion exchange resin and electrochemical oxidation treatment train

Perfluoroalkyl ether carboxylic acids (PFECAs) are a group of emerging recalcitrant contaminants that are being developed to replace legacy per- and polyfluoroalkyl substances (PFAS) in industrial applications and that are generated as by-products in fluoropolymer manufacturing. Here, we report on the removal and destruction of four structurally different PFECAs using an integrated anion exchange resin (AER) and electrochemical oxidation (ECO) treatment train. Results from this work illustrated that (1) flow-through columns packed with PFAS-selective AERs are highly effective for the removal of PFECAs and (2) PFECA affinity is strongly correlated with their hydrophobic features. Regeneration of the spent resin columns revealed that high percentage (e.g., 80%) of organic cosolvent is necessary for achieving 60-100% PFECA release, and regeneration efficiency was higher for a macroporous resin than a gel-type resin. Treatment of spent regenerants showed (1) >99.99% methanol removal was achieved by distillation, (2) >99.999% conversion of the four studied PFECAs was achieved during the ECO treatment of the still bottoms after 24 hours with an energy per order of magnitude of PFECA removal (EE/O) <1.03 kWh/m³ of total groundwater treated, and (3) >85% of the organic fluorine was recovered as inorganic fluoride. Trifluoroacetic acid (TFA), perfluoropropionic acid (PFPrA), and perfluoro-2-methoxyacetic acid (PFMOAA) were confirmed via high-resolution mass spectrometry as transformation products (TPs) in the treated still bottoms, and two distinctive degradation schemes and four reaction pathways are proposed for the four PFECAs. Lastly, dissolved organic matter (DOM) inhibited uptake, regeneration, and oxidation of PFECAs throughout the treatment train, suggesting pretreatment steps targeting DOM removal can enhance the system's treatment efficiency. Results from this work provide guidelines for developing effective separation-concentration-destruction treatment trains and meaningful insights for achieving PFECA destruction in impacted aquatic systems.

Occurrence, spatial distribution, and sources of PFASs in the water and sediment from lakes in the Tibetan Plateau

Per-and polyfluoroalkyl substances (PFASs) are omnipresent globally and received increasing attention recently. However, there are limited data on PFASs in the Tibetan Plateau (TP), a remote high-altitude mountain region, which is regard as an important indicator region to study long-range transport behaviors of contaminants. This study investigates the occurrence, distribution, partitioning behavior, and sources of 26 PFASs in water and sediments from the four lakes of TP. The ΣPFAS concentrations ranged from 338 to 9766 pg L^-1 in water, and 12.2-414 pg g^-1 dry weight in sediments. Perfluorobutanonic acid (PFBA) and perfluorooctane sulfonate (PFOS) were detected in all samples. Qinghai Lake had the highest ΣPFAS concentrations in both water and sediments, while the Ranwu Lake had the lowest. The functional groups and CF₂ moiety units were investigated as essential factors influencing the partition behavior. Principal component analysis (PCA) combined back-trajectory was used to infer possible sources of PFASs. The results suggested that the main source of PFASs in Yamdrok Lake, Namco Lake, and Ranwu Lake on southern TP were mainly originated from South Asia via long-range atmospheric transport (LRAT); while for the Qinghai Lake of northern TP, LRAT, local emissions, and tourism activities were the primary sources of PFASs.

Impacts of PFOAC8, GenXC6, and their mixtures on zebrafish developmental toxicity and gene expression provide insight about tumor-related disease

Concerns about per- and polyfluoroalkyl substances (PFASs) have grown in importance in the fields of ecotoxicology and public health. This study aims to compare the potential effects of long-chain (carbon atoms ≥ 7) and short-chain derivatives and their mixtures' exposure according to PFASs-exposed (1, 2, 5, 10, and 20 mg/L) zebrafish's (Danio rerio) toxic effects and their differential gene expression. Here, PFOA_C8, GenX_C6, and their mixtures (v/v, 1:1) could reduce embryo hatchability and increase teratogenicity and mortality. The toxicity of PFOA_C8 was higher than that of GenX_C6, and the toxicity of their mixtures was irregular. Their exposure (2 mg/L) caused zebrafish ventricular edema, malformation of the spine, blood accumulation, or developmental delay. In addition, all of them had significant differences in gene expression. PFOA_C8 exposure causes overall genetic changes, and the pathways of this transformation were autophagy and apoptosis. More importantly, in order to protect cells from PFOA_C8, GenX_C6, and their mixtures' influences, zebrafish inhibited the expression of ATPase and Ca²⁺ transport gene (atp1b2b), mitochondrial function-related regulatory genes (mt-co2, mt-co3, and mt-cyb), and tumor or carcinogenic cell proliferation genes (laptm4b and ctsbb). Overall, PFOA_C8, GenX_C6, and their mixtures' exposures will affect the gene expression effects of zebrafish embryos, indicating that PFASs may pose a potential threat to aquatic biological safety. These results showed that the relevant genes in zebrafish that were inhibited by PFASs exposure were related to tumorigenesis. Therefore, the effect of PFASs on zebrafish can be further used to study the pathogenesis of tumors.

The Association between Prenatal Per- and Polyfluoroalkyl Substances Exposure and Neurobehavioral Problems in Offspring: A Meta-Analysis

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy has been suggested to be associated with neurobehavioral problems in offspring. However, current epidemiological studies on the association between prenatal PFAS exposure and neurobehavioral problems among offspring, especially attention deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), are inconsistent. Therefore, we aimed to study the relationship between PFAS exposure during pregnancy and ADHD and ASD in offspring based on meta-analyses. Online databases, including PubMed, EMBASE, and Web of Science, were searched comprehensively for eligible studies conducted before July 2021. Eleven studies (up to 8493 participants) were included in this analysis. The pooled results demonstrated that exposure to perfluorooctanoate (PFOA) was positively associated with ADHD in the highest quartile group. Negative associations were observed between perfluorooctane sulfonate (PFOS) and ADHD/ASD, including between perfluorononanoate (PFNA) and ASD. There were no associations found between total PFAS concentration groups and neurobehavioral problems. The trial sequential analyses showed unstable results. Our findings indicated that PFOA and PFOS exposure during pregnancy might be associated with ADHD in offspring and that prenatal PFOS and PFNA exposure might be associated with ASD in offspring. According to the limited evidence obtained for most associations, additional studies are required to validate these findings.

Fluoropolymer: A Review on Its Emulsion Preparation and Wettability to Solid-Liquid Interface

In the preparation of a superamphiphobic surface, the most basic method is to reduce the surface free energy of the interface. The C-F bond has a very low surface free energy, which can significantly change the wettability of the solid-liquid interface and make it a hydrophobic or oleophobic, or even superamphiphobic surface. Based on the analysis of a large number of research articles, the preparation and application progress in fluoropolymer emulsion were summarized. After that, some corresponding thoughts were put forward combined with our professional characteristics. According to recent research, the status of the fluoropolymer emulsion preparation system was analyzed. In addition, all related aspects of fluoropolymer emulsion were systematically classified in varying degrees. Furthermore, the interaction between fluoropolymer structure and properties, especially the interaction with nanomaterials, was also explored. The aim of this review is to try to attract more scholars' attention to fluorocarbon interfacial materials. It is expected that it will make a certain theoretical and practical significance in the preparation and application of fluoropolymer.

Legacy and emerging airborne per- and polyfluoroalkyl substances (PFAS) collected on PM2.5 filters in close proximity to a fluoropolymer manufacturing facility

Large fluoropolymer manufacturing facilities are major known sources of per- and polyfluoroalkyl substances (PFAS), many of which accumulate in groundwater, surface water, crops, wildlife, and people. Prior studies have measured high PFAS concentrations in groundwater, drinking water, soil, as well as dry and wet deposition near fluoropolymer facilities; however, much less is known about near-source PFAS air concentrations. We measured airborne PFAS on PM2.5 filters in close proximity to a major fluoropolymer manufacturing facility (Chemours' Fayetteville Works) located near Fayetteville, North Carolina, USA. Weekly PM2.5 filter samples collected over a six-month field campaign using high-volume air samplers at locations 3.7 km apart, north-northeast and south-southwest of the facility were analyzed for thirty-four targeted ionic PFAS species by liquid chromatography coupled to electrospray ionization tandem mass spectrometry. Twelve emerging and ten legacy PFAS compounds were detected. Thirteen PFAS were found at higher concentrations in these nearfield samples than at regional background sites, suggesting a local source for these compounds. Five emerging and five legacy PFAS compounds had maximum concentrations exceeding 1 pg m-3. PFBA, PFHxA, PFHxDA, PFOS, PMPA, NVHOS, PFO5DoA, and Nafion BP1 contributed the most to the total (legacy + emerging) PFAS concentration (86%). Six PFAS, specifically PFBA, PFOS, PFO5DoA, Nafion BP1, Nafion BP2, and Nafion BP4, provide a consistent representative profile of elevated species across the two sites (with detection frequency >50%). To our knowledge, this is the first study to report both legacy and emerging ionic PFAS in air in close proximity to a U.S. fluoropolymer manufacturing facility.

Vital Environmental Sources for Multitudinous Fluorinated Chemicals: New Evidence from Industrial Byproducts in Multienvironmental Matrices in a Fluorochemical Manufactory

Direct emissions from fluorochemical manufactory are an important source of per- and polyfluoroalkyl substances (PFASs) to the environment. In this study, a wide range of PFASs, including 8 legacy PFASs, 8 long-chain perfluoroalkyl carboxylic acids (PFCAs), and 40 emerging PFASs, were investigated through a target screening in multienvironmental matrices from a fluorochemical manufactory in China. Indoor dust was the most polluted matrix, wherein 52 PFASs were detected, and the median concentration of long-chain PFCA was 276 ng/g. A high level of short-chain PFAS in total suspended particles (median concentration = 416 ng/m³) and the effluent in the manufactory (Σ₄₈PFAS = 212 μg/L) will undoubtedly increase the burden on the surrounding environment. Twenty-four industrial byproducts were ascertained to be generated during the electrochemical fluorination (ECF) process, and eight fluorinated alternatives were considered to be produced during product development. Twelve PFASs were quantified for the first time in the working environments. Perfluoropropane sulfonic acid, perfluoro (2-ethoxyethane) sulfonic acid (PFEESA), and 2-perfluorohexyl ethanoic acid are abundant fluorinated alternatives, with median levels of 1187-17204 ng/g in the dust. Significant positive correlations between ECF-related PFAS products and byproducts indicate that the detected values are strongly connected with the industrial source. Hierarchical cluster analysis further manifests their affiliation. Our findings raise the need for further investigations of emerging PFAS (including the first report of PFAS, such as PFEESA, in the environment) which may be released during the production process in the fluorochemical manufactories.

Home-produced eggs: An important human exposure pathway of perfluoroalkylated substances (PFAS)

Humans are generally exposed to per- and polyfluoroalkyl substances (PFAS) through their diet. Whilst plenty of data are available on commercial food products, little information exists on the contribution of self-cultivated food, such as home-produced eggs (HPE), to the dietary PFAS intake in humans. The prevalence of 17 legacy and emerging PFAS in HPE (N = 70) from free-ranging laying hens was examined at 35 private gardens, situated within a 10 km radius from a fluorochemical plant in Antwerp (Belgium). Potential influences from housing conditions (feed type and number of individuals) and age of the chickens on the egg concentrations was examined, and possible human health risks were evaluated. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were detected in all samples. PFOS was the dominant compound and concentrations (range: 0.13-241 ng/g wet weight) steeply decreased with distance from the fluorochemical plant, while there was no clear distance trend for other PFAS. Laying hens receiving an obligate diet of kitchen leftovers, exhibited higher PFOS and PFOA concentrations in their eggs than hens feeding only on commercial food, suggesting that garden produce may be a relevant exposure pathway to both chickens and humans. The age of laying hens affected egg PFAS concentrations, with younger hens exhibiting significantly higher egg PFOA concentrations. Based on a modest human consumption scenario of two eggs per week, the European health guideline was exceeded in ≥67% of the locations for all age classes, both nearby and further away (till 10 km) from the plant site. These results indicate that PFAS exposure via HPE causes potential human health risks. Extensive analysis in other self-cultivated food items on a larger spatial scale is highly recommended, taking into account potential factors that may affect PFAS bioavailability to garden produce.