Per- and poly-fluoroalkyl substances (PFAS) and female reproductive outcomes: PFAS elimination, endocrine-mediated effects, and disease

Identification of new PFAS for severe interference with thyroid hormone transport: A combined in vitro/silico approach

A tiered in vitro/in silico approach was developed to screen 12,654 per- and polyfluoroalkyl substances (PFAS) for their potential to disrupt the thyroid hormone transport. Initially, a set of 45 PFAS was tested using TTR-TRβ-CALUX bioassay, which was subsequently employed to develop a classification model, distinguishing active and inactive PFAS. The model fulfills all good practices for QSAR model validation and can predict whether a given PFAS can disrupt plasma transport of the thyroid hormone (T4). Subsequently, active compounds were used to develop two regression approaches: (i) multiple linear regression MLR, and (ii) second approach aimed at identifying multiple valid QSAR models based on different data-splitting strategies. Finally, a comprehensive virtual screening of a large PFAS dataset was conducted to assess their potency in disrupting thyroid hormone transport. The predictions indicated that more than 7500 compounds were active with over 100 PFAS potentially causing even greater adverse effects than PFOA. These findings highlight the critical role of integrating New Approach Methodologies (NAM)-based in vitro toxicity testing with multifaceted molecular modeling in assessing the risks associated with PFAS contamination in environmental matrices.

Association and binding interaction between per- and polyfluoroalkyl substances and maternal thyroid hormones: A case study based on a prospective birth cohort in Wuxi, China

BACKGROUND AND AIM

The relationship between prenatal exposure to per- and polyfluoroalkyl substances (PFASs), a well-known endocrine disruptor, and thyroid hormones (THs) levels remains unclear. Therefore, this study aimed to investigate this relationship in a birth cohort during the second trimester.

METHOD

This prospective study included 562 pregnant women in the Wuxi Birth Cohort from 2019 to 2021 and quantified the serum concentrations of 23 PFASs and 5 THs. Multiple statistical models were used to assess the associations between individual or combined PFASs concentrations and THs, while molecular docking simulated the interactions between PFASs and four thyroid-related proteins.

RESULTS

The median concentration of ∑23PFASs was 71.91 ng/mL, with perfluorovaleric acid (PFPeA) (18.13 ng/mL) emerging as the predominant PFAS. Most PFASs were negatively associated with maternal free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels, whereas perfluorobutane sulfonate (PFBS) was positively correlated with TSH levels. A similar trend was observed in the weighted quantile sum (WQS) model, in which combined PFASs exposure was inversely associated with the FT4 and TSH levels. Molecular docking results showed that compared with TH natural ligand thyroxine (T4), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl- PFESA) exhibited relatively high binding affinity with thyroid-related proteins (-6.6 to -9.8 kcal/mol vs. T4: -5.6 to -8.6 kcal/mol). Furthermore, PFASs with medium chain lengths and sulfonic acid groups exhibited enhanced protein-binding properties.

CONCLUSION

PFASs exposure may affect THs homeostasis during pregnancy. Moreover, different types and concentrations of PFASs have different effects on THs in the maternal serum.

The Menstrual Cycle as a Vital Sign: a comprehensive review

Some medical professional organizations have advocated for including the menstrual cycle as a vital sign in adolescence, but not in adulthood. However, documenting menstrual cycle patterns is not routine clinical or research practice. Vital signs are used to predict health outcomes, indicate needed treatment, and monitor a clinical course. They can help identify pathologies, affirm wellness, and are responsive to exposures. Here we review the scientific evidence showing how the menstrual cycle meets these criteria and should therefore be treated as a vital sign. Using key words and controlled vocabulary terms, we carried out multiple literature searches, prioritizing the inclusion of systematic reviews, meta-analyses, and clinical practice guidelines. This review describes how the menstrual cycle is a health indicator, can cyclically impact health conditions, and its associations with long-term post-menopausal health outcomes. We review exposures influencing the menstrual cycle, evidence underlying its use to optimize wellness, and available tools for documenting cycles. Supplementary materials include patient handouts on menstrual cycle tracking, and an index of related clinical practice guidelines and reviews by subject. The menstrual cycle is a vital sign from menarche through menopause, an underutilized but powerful tool for understanding gynecological and general health.

Association Between Serum Levels of Perfluoroalkyl and Polyfluoroalkyl Substances and Dental Floss Use: The Double-Edged Sword of Dental Floss Use-A Cross-Sectional Study

BACKGROUND

Although evidence suggests that dental floss contains perfluoroalkyl and polyfluoroalkyl substances (PFASs), it is still uncertain whether the use of dental floss contributes to an increased risk of PFAS exposure.

METHODS

We analysed data on serum PFAS concentrations and dental floss usage in a cohort of 6750 adults who participated in the National Health and Nutrition Examination Survey (NHANES) from 2009 to 2020. In our study, we used logistic regression, a survey-weighted linear model, item response theory (IRT) scores, inverse probability weights (IPWs) and sensitivity analysis to assess the potential impact of dental floss usage on human serum PFAS levels.

RESULTS

The analysis of six PFASs revealed that dental floss users had higher serum concentrations of perfluorooctanoic acid (PFOA) compared with non-users, while serum concentrations of other PFASs were lower. Dental floss users recorded a lower level of overall PFAS burden score compared with non-users. Sensitivity analysis showed a statistically significant increase in serum PFOA concentration among dental floss users.

CONCLUSION

Our findings suggest that the use of dental floss may be associated differently with serum concentrations of specific PFASs. Among a large representative sample of U.S. adults, individuals reporting the use of dental floss had lower levels of serum PFASs overall, with the exception of PFOA, which was slightly elevated. Dental floss is an important oral hygiene tool, and further research is needed to clarify its role in PFAS exposure.

Integrated PBPK Modelling for PFOA Exposure and Risk Assessment

Per- and polyfluoroalkyl substances (PFASs) pose significant public health concerns due to their environmental persistence, bioaccumulation, and ubiquitous presence in human biomonitoring (HBM) data, despite regulatory restrictions. This study establishes a deterministic pharmacokinetic model for perfluorooctanoic acid (PFOA), enabling the estimation of PFOA concentrations in major human organs, even at low doses. The model integrates accumulation and recirculation mechanisms of PFOA in hepatic and renal tissues, leveraging publicly available HBM datasets (e.g., HBM4EU, NHANES, literature) to reconstruct bodyweight-normalized intake levels. Importantly, due to the extremely low urinary excretion concentrations of PFOA, most datasets were derived from blood-based measurements, particularly serum while confirming urine as unreliable biomarker of exposure. The analysis underscores the effectiveness of regulatory efforts in reducing PFOA exposures, as evidenced by declining time-trends in estimated exposure levels in recent studies. Risk characterization ratios were calculated based on recommended limits set by the European Food Safety Authority (EFSA), the United States, and Australia. While EFSA's tolerable weekly intake (TWI) indicated a high risk, other regulatory limits suggested less concern about risk at these intake levels. These findings highlight the need for continuous re-evaluation of exposures and targeted studies to identify key determinants of PFOA exposure, informing future regulatory measures. The study emphasizes the critical role of physiologically based pharmacokinetic (PBPK) modeling, HBM data, and exposure reconstruction in advancing chemical risk assessment. These tools form a science-based framework integral to the Chemical Strategy for Sustainability (CSS), enabling accurate predictions of internal exposure levels, empirical validation of models, and robust assessments of real-world exposure scenarios. The integration of these approaches supports the CSS goals of minimizing chemical risks while promoting innovation, ultimately contributing to a sustainable and protective regulatory landscape for human health and the environment.

United States Environmental Protection Agency's Perfluorooctanoic Acid, Perfluorooctane Sulfonic Acid, and Related Per- and Polyfluoroalkyl Substances 2024 Drinking Water Maximum Contaminant Level: Part 2 - Fifteen Misconceptions About the Health Hazards

This paper examines widely held beliefs about the six per- and polyfluoroalkyl substances (PFAS) addressed in the final U.S. Environmental Protection Agency's (EPA) rule on PFAS in drinking water (e.g., the Maximum Contaminant Levels - MCLs). Based on our understanding of the scientific literature and the comments submitted by stakeholders regarding the EPA's regulation that was promulgated in April 2024, we identified 15 misconceptions that had a weak scientific foundation. These are now memoralized in the MCLs for the six PFAS but remain debated due to ongoing ambiguous research findings. Many critics of the MCLs found the EPA's systematic review of the published relevant information, particularly the toxicology of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), to be inadequate. The following seven views are among the most important. First, the EPA asserted that the toxicology of these six chemicals was poorly understood and lacked sufficient data to determine a safe daily intake level for chronic health effects; nonetheless, they promulgated what may be the costliest environmental regulation to date. Notably, adverse effects remain difficult to demonstrate in occupationally exposed individuals even at blood concentrations 50-100 times higher than current background PFAS levels. Second, the Agency indicated that the epidemiology data showed that exposure to PFOA and PFOS caused kidney and potentially other cancers, yet the data were equivocal and do not support that assertion. Third, it was stated that specific non-cancer effects, such as heart disease, would be prevented under the promulgated rule; however, the studies that they relied upon do not show an increased incidence of heart disease even in highly exposed populations. Fourth, the Agency relied on animal data to support its views on the likely toxic effects in humans, despite ample toxicology data that animals, particularly rodents, are poor predictors of the human response to PFAS exposures. Fifth, the EPA predicted a reduction in healthcare expenditures that would offset much of the cost of complying with the MCL, but, they did not have adequate data to support this prediction. Sixth, the EPA suggested that these six PFAS act through a shared mechanism of action (i.e., PPARα pathway induction); however, data indicate that PPARα induction in humans may be 80% less than what is observed in rodents. Also, induction of the PPARα pathway is not a cause of systemic disease. Seventh, the Agency failed to disclose that achieving the new MCL would yield negligible reductions in blood PFAS levels even among highly exposed populations, given drinking water accounts for only 20% or less of total PFAS exposure. The survey that could answer that question, the EPA's fifth Unregulated Contaminant Monitoring Rule, was only 25% complete at the time the MCL was promulgated. Overall, our analysis concluded that while the EPA's intent to regulate these chemicals due to their environmental presence was necessary, the derivation of the MCLs and the alleged health effects was based on the application of the precautionary principle rather than robust scientific evidence.

Per- and polyfluoroalkyl substances (PFAS) in placental compartments: Histopathological and toxicological data integration in an Italian cohort

Per- and polyfluoroalkyl substances (PFAS) are synthetic environmental contaminants with widespread industrial and consumer applications, characterized by strong chemical stability and environmental persistence. Recent studies have highlighted placental permeability to PFAS, though evidence of direct histopathological impairment remains limited. This study aimed to investigate potential associations between PFAS exposure and histopathological abnormalities in placental samples. A total of 23 at-term pregnant women were recruited from two hospitals in Italy as part of a multicenter study. Placental samples, divided into maternal (decidua) and fetal (villi) compartments, were analyzed for PFAS concentration and histopathological alterations. PFAS were detected in 95.7 % of samples. The most frequently detected PFAS were PFOS (88 %), followed by PFHxS (83 %), PFOA (83 %), PFBS (54 %) and PFHxA (54 %). Preliminary findings suggest variable PFAS concentrations among subjects, with histopathological examination revealing placental alterations of potential clinical relevance. The observed histopathological alterations, particularly in cases of malperfusion and angiogenesis changes, suggest that PFAS may contribute to placental dysfunction, potentially affecting pregnancy outcomes. In particular, it could be hypothesized that PFHxA could exert an adverse influence on placental angiogenesis, due to pre-placental hypoxia stimulating the angiogenesis and resulting in increased ramification and number of branches. While direct causative links remain to be fully elucidated, these results underscore the need for further investigations into PFAS-related placental effects and their implications for fetal development.

A review of multi-contaminant risks in textile dyeing sludge pyrolysis: Transformation mechanisms and mitigation strategies

Textile dyeing sludge (TDS), an industrial byproduct containing various pollutants like heavy metals, polycyclic aromatic hydrocarbons (PAHs), microplastics, per- and poly-fluoroalkyl substances (PFAS), necessitates efficient treatment to mitigate environmental risks. Pyrolysis has become an effective alternative for treating TDS due to its advantages in carbon mitigation and resource utilization compared to incineration and landfilling. However, a comprehensive understanding of the generation and transformation mechanisms of multi-contaminants during pyrolysis is still lacking, hindering its large-scale application. This review systematically analyzes the behavior of multi-contaminants during pyrolysis, with a special concern on the emerging contaminants, including PAH derivatives, microplastics, and PFAS. The potential application and environmental risks of TDS-derived biochar are also outlined, followed by a comprehensive investigation on the pollution mitigation of pyrolysis regulation strategies. The evaluation of risks posed by emerging contaminants and long-term application of biochar, as well as the source control of multi-contaminants is recognized as the dilemma, which stems from the limitations in quantifying method of emerging pollutants, the variability of biochar properties, complicated environmental influences over long-term application, and the tradeoffs among multi-contaminants during pyrolysis regulation. Future research is proposed to prioritize (1) quantitative risk assessment of emerging contaminants and long-term application of biochar, (2) elucidating pollutant formation and transformation pathways under pyrolysis regulation strategies for targeted control, and (3) multi-objective optimization to balance product valorization and integrated risk of multi-contaminants. This review aims to provide guidance for the research on pollution risk evaluation and control in the pyrolysis process of TDS.

Insight into perfluorooctanoic acid-induced impairment of mouse embryo implantation via single-cell RNA-seq

Perfluorooctanoic acid (PFOA) is an environmentally persistent chemical that poses significant risks to human health. Studies have shown that PFOA affects female reproduction, but the specific impact on endometrial receptivity and the underlying mechanisms remain poorly understood. In this study, we investigated the effects of low-dose PFOA exposure through drinking water on endometrial receptivity in a murine model. Our results demonstrate that PFOA exposure significantly impaired endometrial receptivity, which led to a marked decrease in embryo implantation rates. Utilizing single-cell RNA sequencing technology, we conducted a comprehensive analysis that revealed specific mechanisms by which PFOA disrupts the function and development of endometrial epithelial cells. Notably, we identified dysregulation of the ANGPTL (angiopoietin-like) signaling pathway, which is critical for communication between endometrial stromal and epithelial cells, ultimately contributing to embryo implantation failure. These findings provide novel insights into the reproductive toxicity of PFOA and highlight potential targets for therapeutic interventions aimed at addressing infertility associated with environmental contaminants.

PFC/PFAS concentrations in human milk and infant exposure through lactation: a comprehensive review of the scientific literature

Per- and polyfluoroalkyl substances (PFAS), previously known as perfluorinated compounds (PFC), are a group of synthetic chemicals widely used over the past decades. Their extensive application, combined with their environmental persistence, has contributed to their ubiquitous presence in the environment and the associated toxicological risks. Regarding humans, blood serum testing remains the primary method for biomonitoring PFAS exposure, while breast milk has also been used due to the transfer of these substances from mothers to infants during lactation. This paper aims to review the scientific literature (using PubMed and Scopus databases) on PFAS concentrations in the breast milk of non-occupationally exposed women. Where available, the estimated daily intake of these compounds by breastfeeding infants is also examined. The reviewed studies are categorized by continent and country/region, revealing a significant lack of data for many countries, including both developed and developing nations. The findings indicate substantial variability in PFAS concentrations, influenced by factors such as geographic location, sampling year, and the specific PFAS analyzed. Among the identified compounds, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are most commonly detected, along with perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA), being the only PFAS with regulated maximum levels in certain foodstuffs. Most studies were conducted before the implementation of the current (updated) tolerable weekly intake (TWI) values for these substances. Consequently, the majority reported a low health risk for breastfeeding infants, even in high-intake scenarios. Nevertheless, biomonitoring studies are urgently needed in countries with limited or no data, and new investigations should assess whether current estimated intakes exceed the updated TWI. Special focus should be given to rural and industrial areas where exposure levels remain poorly understood.

PFAS regulations and economic impact: A review of U.S. pulp & paper and textiles industries

Public concern over per- and polyfluoroalkyl substances (PFAS) continues to grow as evidence highlights their persistence, bioaccumulation potential, and adverse health effects. Increasing detections in drinking water, consumer products, and industrial discharges have intensified regulatory scrutiny. This review examines the evolving PFAS regulatory landscape in the United States, focusing on the pulp, paper, and textiles industries, which contribute significantly to PFAS contamination through wastewater discharges, end-product disposal, and the absence of dedicated removal technologies. PFAS emissions from food packaging alone are estimated at 2,300 kg annually. Addressing contamination presents substantial economic challenges, with wastewater treatment costs projected to reach USD 3 billion annually and growing risks of legal liabilities exemplified by paper mill settlements reaching USD 11.9 million for historical pollution. Large-scale remediation of PFAS remains financially prohibitive, with estimates exceeding the global gross domestic product (GDP) of USD 106 trillion. Additionally, healthcare costs for PFAS-linked diseases exceed USD 62 billion and further emphasize the need for prevention. State-level restrictions on PFAS-containing consumer products are expanding, particularly in food packaging and textiles, which are now the most regulated across the United States. As PFAS-containing products face increasing market limitations and potential loss of sustainability certifications, which have already reduced sales growth by 70% in some cases, transitioning to non-fluorinated alternatives could significantly mitigate economic risks for paper and textiles companies. Within this context, this review highlights the urgency of integrating policy, technological innovation, and economic incentives to accelerate the transition away from PFAS and mitigate long-term environmental and financial liabilities.

Temporal and cross-sectional associations of serum per- and polyfluoroalkyl substances (PFAS) and lipids from 1986 to 2016 - The Tromsø study

INTRODUCTION

Per- and polyfluoroalkyl substances (PFAS) have been linked to effects on human lipid profiles, with several epidemiological studies reporting associations between specific PFAS and blood lipid concentrations. However, these associations have been inconsistent, and most studies have focused on cross-sectional analyses with limited repeated measurements.

OBJECTIVE

In this study, we investigated associations between serum PFAS concentrations and major blood lipid classes over a 30-year period (1986-2016) and up to five time points. Lipids analyzed included total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG).

METHODS

This study included 145 participants from The Tromsø Study, Norway, who donated plasma samples three to five times over the study period. Linear mixed-effects (LME) models assessed longitudinal associations between PFAS and lipid classes, while multiple linear regression (MLR) models were used for cross-sectional associations.

RESULTS

LME models demonstrated positive longitudinal associations between perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotridecanoic acid (PFTrDA) with TC. Additionally, PFOA, PFDA, PFUnDA, PFDoDA, and PFTrDA were associated with LDL-C, and PFUnDA and summed perfluorooctane sulfonate isomers (∑PFOS) with HDL-C. Cross-sectional analyses corroborated positive associations between the six PFAS compounds and TC at least three times, but the LDL-C and HDL-C associations were not confirmed. Summed perfluorooctane sulfonamide isomers (∑PFOSA) showed a negative association with LDL-C longitudinally, but this was not confirmed cross-sectionally. No associations were observed between PFAS and TG, longitudinally or cross-sectionally.

CONCLUSION

Concentrations of multiple PFAS were positively associated with blood lipids in longitudinal analyses, with the most consistent associations observed between six PFCA compounds and TC. These findings highlight the need for further investigation into these complex associations.

Per- and polyfluoroalkyl substances and type 2 diabetes among older adults: Synthesizing cross-sectional population study and meta-analysis

The effects of per- and polyfluoroalkyl substances (PFASs) on type 2 diabetes (T2D) remain unclear. We aimed to explore the effects of PFASs exposure on glucose metabolism disorders in older adults. We enrolled 704 elderly individuals aged over 65 years from Wuhan, China. Plasma concentrations of 12 PFASs were measured using liquid chromatography-mass spectrometry. Generalized linear models and quantile-based g computation (qgcomp) were employed to evaluate the effects of individual and combined PFAS exposures on T2D risk. Additionally, a meta-analysis was conducted to consolidate findings reported in the literature for validation purposes. The detection rate of all 12 PFASs exceeded 80%, with median concentrations ranging from 0.01 to 15.22 ng/mL. Single exposure analysis revealed an inverse association between perfluorododecanoic acid (PFDoA) and impaired fasting glucose (IFG), as well as between PFDoA, perfluoroundecanoic acid (PFUdA), perfluorodecanoic acid (PFDA), perfluorononanoic acid (PFNA), and perfluorooctanoic acid (PFOA) and T2D risk (P < 0.05). Quantile-based g-computation analysis showed an inverse association between the PFAS mixture and IFG and T2D risk, although these associations lacked statistical significance. PFDA exhibited the greatest weight in the negative associations with IFG and T2D. Meta-analysis demonstrated an inverse association between PFDA and PFUdA and T2D risk, and PFOA demonstrated an inverted U-shaped nonlinear dose-response relationship with the risk of T2D (Pnonlinear = 0.026). The potential impact of PFAS exposure on glucose metabolism merits attention, underscoring the need for a thorough comprehension of the biological mechanisms underlying PFAS-mediated metabolic effects to facilitate precise risk assessment.

Assessing the impact of per- and polyfluoroalkyl substances on pregnancy loss: An environmental-wide association study in Northwest China

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are emerging environmental contaminants with potential metabolic and endocrine-disrupting properties that may affect women's reproductive health. However, their specific role in pregnancy loss remains relatively understudied.

OBJECTIVES

This study aimed to assess the association between exposure to multiple PFAS and the association with pregnancy loss (PL) in a population from Northwest China using an environment-wide association study (EWAS) approach.

METHODS

A case-control study was conducted at a university-affiliated reproductive center, enrolling 348 women with a history of PL and 320 controls with at least one live birth and no history of pregnancy loss. Serum concentrations of ten PFAS were quantified using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) following a standardized extraction and purification protocol. Demographic and clinical data were collected via a structured questionnaire. An elastic net regression model (ENRM) was employed for variable selection, identifying PFASs to be included in the subsequent EWAS analysis. Associations between individual PFAS and PL were then evaluated using logistic regression, and EWAS was utilized to explore the overall associations between PFAS mixture exposure and PL, accounting for potential interactions and multicollinearity.

RESULTS

The EWAS identified five PFASs-PFPeS, PFHxS, PFOA, PFOS, and PFNA-with significantly higher exposure odds in pregnancy loss cases versus live birth controls (adjusted ORs: 1.82 [1.31-2.62], 1.34 [1.19-1.51], 1.73 [1.46-2.07], 1.33 [1.14-1.56], and 1.73 [1.40-2.15], respectively). Subgroup analyses confirmed robust associations, with PFOA consistently linked to elevated exposure odds across demographic and clinical strata.

CONCLUSION

This study demonstrates a significant association between exposure to multiple PFAS, notably PFPeS, PFHxS, PFOA, PFOS, and PFNA, and an increased risk of pregnancy loss in a Northwest Chinese population. The particularly robust association observed with PFOA across diverse subgroups underscores its potential as a significant environmental risk factor for PL. These findings highlight the need for further research to elucidate the underlying mechanisms and to develop strategies for reducing PFAS exposure among women of reproductive age.

Serum PFAS and lipid concentrations in Ecuadorian adolescents

There is growing evidence that per- and polyfluoroalkyl substances (PFAS) may alter serum lipid concentrations; however, this topic is understudied in adolescents and Latin American populations. We aimed to characterize these associations among adolescents in Ecuador's main floricultural region. This cross-sectional study included 97 adolescents ages 11-17 years from Pedro Moncayo County, Ecuador. Generalized estimating equation models were applied to estimate the associations of serum perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) concentrations with serum lipids. Models were adjusted for age, gender, height, body mass index (BMI), acetylcholinesterase (AChE) activity, and hemoglobin concentrations. Significant inverse relationships between PFAS and triglycerides were observed in females (% lipid difference per 50% increase in: PFOS= -15.0% [95%CI: -24.72, -4.06], PFNA= -25.49% [-36.93, -12.00], and PFOA= -16.55% [-28.16, -3.07]) but not in males. No associations were observed between total cholesterol, high-density lipoprotein (HDL), or low-density lipoprotein (LDL) cholesterol and any PFAS. PFOS, PFOA, and PFNA were inversely associated with triglycerides in adolescent females but not males. Further characterization of gender-specific associations of PFAS and blood lipids in adolescents is warranted.

Associations of exposure to individual polyfluoroalkyl substances and their mixtures with vitamin D biomarkers in postmenopausal women

The potential impact of polyfluoroalkyl substances (PFAS) on vitamin D status in postmenopausal women remains unexplored. This study examined the effects of individual PFAS and their combined exposures on vitamin D biomarkers among 2114 postmenopausal women utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2003-2018. The serum levels of four PFAS compounds, including perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), and perfluorononanoic acid (PFNA), were assessed alongside the 25-hydroxyvitamin D [25(OH)D] level. Our findings indicated that elevated log-transformed PFAS concentrations were significantly associated with reduced 25(OH)D levels (βPFOS: -15.969, 95 % CI: -19.154, -12.785; βPFOA: -17.288, 95 % CI: -22.446, -12.131; βPFNA: -8.510, 95 % CI: -12.148, -4.871; βPFHxS: -4.056, 95 % CI: -7.003, -1.110) and increased odds of vitamin D deficiency (ORPFOS: 2.495, 95 % CI: 1.685, 3.694; ORPFOA: 3.146, 95 % CI: 1.823, 5.429; ORPFNA: 1.906, 95 % CI: 1.357, 2.677; ORPFHxS: 1.480, 95 % CI: 1.109, 1.976). These associations were modified by race, the family incomepoverty ratio and the survey cycle. Notably, non-Hispanic White individuals presented a stronger inverse association between PFOS exposure and 25(OH)D levels. Bayesian kernel machine regression and weighted quantile sum analyses demonstrated that the effects of exposure to mixtures of the four studied PFAS were consistent with the effects of exposure to individual PFAS. These findings indicate that exposure to individual PFAS, particularly PFOA and PFOS, and their four mixtures may adversely affect serum 25(OH)D concentrations in postmenopausal women, underscoring the need for further investigation into the potential impact of PFAS on vitamin D status in this population.

Impact of Persistent Endocrine-Disrupting Chemicals on Human Nuclear Receptors: Insights from In Silico and Experimental Characterization

Endocrine-disrupting chemicals (EDCs) are notable for their persistence, bioaccumulation, and associations with cancer. Human nuclear receptors (hNRs) are primary targets disrupted by these persistent EDCs, resulting in alterations to xenobiotic metabolism, lipid homeostasis, and endocrine function, which can lead to carcinogenic effects. Despite their hazardous effects, comprehensive studies on EDC interactions and their impacts on hNRs remain limited. Here, we profiled the interactions of persistent EDCs, including PFAS, plastic additives, bisphenols, polybrominated diphenyl ethers, and phthalates, with key hNRs such as PXR, CAR, PPARα, PPARγ, PPARδ, AR, and RORγt. Through controlled molecular docking simulations, we observed strong binding of the EDCs to these receptors. Further analysis showed that EDCs exhibit strong binding activity towards hNRs by preferentially interacting with hydrophobic amino acids, namely leucine, isoleucine, methionine, and phenylalanine. PFAS demonstrated the highest binding affinity, characterized by a combination of complementary hydrophobic interactions from their fluorinated carbon chains and polar interactions from their functional groups (e.g., carboxylate, sulfonate) across all receptors. Distinct polycyclic and hydrophobic trends, contributing to strong NR binding, were evident in non-PFAS and nonplastic EDCs. The hNR activity assay in HepG2 cells revealed agonistic effects of dicyclohexyl phthalate (DCHP) and di-2-ethylhexyl phthalate (DEHP) on most receptors, except for PPARα. The hNR transcription factor pathway assay in HepG2 cells demonstrated increased gene expression of VDRE and PXR, suggesting potential chronic effects on xenobiotic metabolism and calcium homeostasis. Overall, our findings demonstrate the need for further research into the endocrine disruption and carcinogenic effects of these persistent EDCs.

Per- and polyfluoroalkyl substances in environment and potential health impacts: Sources, remediation treatment and management, policy guidelines, destructive technologies, and techno-economic analysis

Per- and polyfluoroalkyl Substances (PFAS), also known as forever chemicals and ubiquitous persistence, pose significant public health challenges due to their potential toxicity, particularly in drinking water and soil contamination. However, PFAS occurrence and their concentrations in different environmental matrices vary globally, but factors influencing trends, transport, fate, toxicity, and interactions with co-contaminants remain largely unexplored. Therefore, this review critically examines the state-of-the-art worldwide PFAS sources, distribution, and pathways, and evaluates how PFASs are processed in wastewater treatment, generally, which causes severe problems with the quality and safety of drinking water. Importantly, the review also underscores health issues due to PFAS consumption and recent research trends on developing effective treatment strategies to manage PFAS contamination. Potential effects of PFAS were linked to urban land use and the proportion of wastewater effluent in streamflow. Besides, major emphasis was provided on challenges for conventional treatment, destructive technologies, environmental accumulation, precursor transformation, and cost-investment related to PFAS removal technologies. To combat PFAS contamination, this review proposes a framework that promotes the comprehensive identification of prevalent compounds, with a focus on their eradication through knowledge-based and targeted analysis. Additionally, it explores the ongoing debate surrounding PFAS laws and legal frameworks, offering ideas for enhancing contamination management. Lastly, this review provides a strategic plan for improving response and preparedness, serving as a foundation for addressing future environmental challenges and informing health risk assessments.

The Association Between Per- and Polyfluoroalkyl Substances Exposure and Thyroid Hormones in Men and Non-Pregnant Women: A Systematic Review and Meta-Analysis

Studies have shown that per- and polyfluoroalkyl substances (PFAS) may impact thyroid function in human health. While the consistency between PFAS exposure and thyroid health effects in pregnant women has been validated, the effects on men and non-pregnant women remains inconclusive. To address this, a meta-analysis was carried out in this paper, with 14 eligible studies retrieved from Embase, PubMed, and Web of Science that were published up to 2 June 2024, focusing on the relationship between PFAS exposure and its effect on thyroid hormone levels in the human body. The thyroid function indexes analyzed included thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4). The estimated value (β) and the corresponding confidence interval (95% CI) were extracted from the literature. A heterogeneity test was carried out, and the sensitivity analysis and publication bias of the studies were analyzed using Stata 18.0. The results revealed that in men and non-pregnant women, PFOA was positively correlated with FT3 (β = 0.011, 95% CI = 0.001, 0.02, I2 = 13.4). However, no significant associations were found between exposure to other PFAS and thyroid hormones. A subgroup analysis further indicated that the correlations between PFAS exposure and thyroid hormone levels were more significant in adolescents, in both America and Europe.

Research Progress in Current and Emerging Issues of PFASs' Global Impact: Long-Term Health Effects and Governance of Food Systems

Per- and polyfluoroalkyl substances (PFASs) are found everywhere, including food, cosmetics, and pharmaceuticals. This review introduces PFASs comprehensively, discussing their nature and identifying their interconnection with microplastics and their impacts on public health and the environment. The human cost of decades of delay, cover-ups, and mismanagement of PFASs and plastic waste is outlined and briefly explained. Following that, PFASs and long-term health effects are critically assessed. Risk assessment is then critically reviewed, mentioning different tools and models. Scientific research and health impacts in the United States of America are critically analyzed, taking into consideration the Center for Disease Control (CDC)'s PFAS Medical Studies and Guidelines. PFAS impact and activities studies around the world have focused on PFAS levels in food products and dietary intake in different countries such as China, European countries, USA and Australia. Moreover, PFASs in drinking water and food are outlined with regard to risks, mitigation, and regulatory needs, taking into account chemical contaminants in food and their impact on health and safety. Finally, PFAS impact and activities briefings specific to regions around the world are discussed, referring to Australia, Vietnam, Canada, Europe, the United States of America (USA), South America, and Africa. The PFAS crisis is a multifaceted issue, exacerbated by mismanagement, and it is discussed in the context of applying the following problem-solving analytical tools: the Domino Effect Model of accident causation, the Swiss Cheese Theory Model, and the Ishikawa Fish Bone Root Cause Analysis. Last but not least, PFASs' impacts on the Sustainable Development Goals (SDGs) of 2030 are rigorously discussed.

Emerging per- and polyfluoroalkyl substance perfluoro-(3,5,7,9-tetraoxadecanoic) acid (PFO4DA) impairs steroidogenesis and spermatogenesis by suppressing StAR and CYP11A1 expression in mice

Perfluoroalkyl ether carboxylic acids (PFECA) represent an important group of emerging per- and polyfluoroalkyl substances (PFAS). PFECA have been found in a variety of environmental matrices. While legacy PFAS have been extensively documented for their reproductive toxicity, the health implications of emerging alternatives like PFECA remains unclear. The present study is aimed at investigating the potential reproductive toxicity of perfluoro-(3,5,7,9-tetraoxadecanoic) acid (PFO4DA), a type of PFECA, through combining in vivo and in vitro assays. Adult male BALB/c mice were exposed to 2 and 10 mg/kg body-weight/day of PFO4DA via oral gavage for four consecutive weeks. While no overt structural or morphological changes were observed in the testes following PFO4DA exposure, significant reductions in both sperm quantity and quality were evident, correlating with increased PFO4DA dosage. PFO4DA exposure compromised the integrity of the blood-testis barrier (BTB) and led to a moderate decrease in BTB-associated junction proteins, including Connexin-43 and Claudin-11. Notably, PFO4DA disrupted androgen production, resulting in a significant reduction in testosterone (T) levels (> 60 %) in both serum and testicular tissue. Mechanistic analysis revealed that PFO4DA significantly repressed the expression levels of steroidogenic genes StAR and CYP11A1 both in testes and in cultured Leydig cells (TM3). These findings suggest that PFO4DA primarily targets the steroidogenic pathway in Leydig cells by suppressing StAR and CYP11A1, thereby inhibiting T synthesis. The subsequent T deficiency impairs Sertoli cell function and BTB integrity, ultimately disrupting spermatogenesis and impacting male reproductive health.

Mitochondrial activity and steroid secretion in mouse ovarian granulosa cells are suppressed by a PFAS mixture

The accumulation of a number of per- and polyfluoroalkyl substances (PFASs) in ovarian follicular fluid (FF) has been documented, raising serious questions about their impact on female fertility. Here, we tested the hypothesis that a mixture of PFASs acts in a paracrine manner on granulosa cells (GCs) as a metabolism-disrupting chemical. We selected perfluorooctane sulfonate (PFOS; 22.4 ng/mL), perfluorooctanoic acid (PFOA; 14.5 ng/mL), perfluorohexane sulfonate (PFHxS; 21.3 ng/mL), perfluorodecanoic acid (PFDA; 0.9 ng/mL), perfluoroheptane sulphonate (PFHpA; 0.6 ng/mL), perfluoroundecanoic acid (PFUnDA; 0.4 ng/mL), and perfluorononanoic acid (PFNA; 2 ng/mL), which were the most commonly detected PFASs in FF of women undergoing assisted reproductive technology treatment. Exposure of mouse GCs to the PFAS mixture decreased the amount of active mitochondria and the mitochondrial membrane potential, which correlated with a reduction in ATP production and inhibition of oxidative phosphorylation (OXPHOS). At the same time, expression of the mitochondrial membrane-associated steroidogenic enzyme 3-beta-hydroxysteroid dehydrogenase (3βHSD) and production of the major steroids progesterone and estradiol were decreased. In addition, expression and activity of superoxide dismutase 1 (SOD1), an enzyme that neutralizes reactive oxygen species (ROS), were decreased while ROS levels and lipid peroxidation were increased without cell death, indicating that the PFAS mixture had subtoxic effects. Our results show that PFAS mixtures, at concentrations similar to those found in human FF led to GC dysfunction by impairing mitochondrial function and steroid secretions and therefore may have implications for reproductive health.

Sex-Specific Effects of Environmental Pollutants on Pulmonary Immune Responses

Environmental pollutants can adversely impact various physiological processes, affecting systems such as the respiratory and immune systems. Immune responses are influenced by various factors including age, hormonal status, genetic background, and notably, sex, with effects extending to both innate and adaptive immunity. External factors, like environmental pollutants, can also disrupt innate and/or adaptive immunity and compromise pathogen recognition and memory against future infections. Furthermore, environmental pollutants can play a pivotal role in the development and exacerbation of many chronic respiratory diseases. It is becoming increasingly evident that environmental pollutants elicit sex-specific effects across different species. This review highlights recent findings on the intricate interplay between sex differences and immune-related effects induced by environmental pollutants, with a particular focus on the dysregulation of pulmonary immune responses.

In Vitro Investigation of Perfluorooctane Sulphonate and Perfluorooctanoic Acid on Boar Spermatozoa Agglutination

Various toxic agents are associated with male infertility, including perfluoroalkyl substances (PFAS), which are emerging as significant contributors due to their physico-chemical properties that exhibit a propensity for bioaccumulation and potentially pose reproductive risks. The aim of this study was to analyse the effects of perfluorooctane sulphonate (PFOS) and perfluorooctanoic acid (PFOA) on boar spermatozoa during capacitation through a focus on agglutinate formation. A second objective was to assess the influence of d-penicillamine (d-Pen) on boar spermatozoa agglutinate prevention. PFOS and PFOA in sublethal concentrations reduced the proportion of spermatozoa that achieved capacitation, PFOS increased to 35% the spermatozoa mortality and both toxic compounds generated an abnormally excessive increase in rosette-type agglutinates that formed non-mobile aggregates (only vibrant), like those that form during physiological capacitation. This increase in agglutinates came at the expense of available free spermatozoa for fertilisation. Treatment with d-Pen, however, significantly reduced rosette formation by PFAS. Further study of the underlying mechanisms revealed that exposure to PFOS and PFOA led to decreased free sulfhydryl (SH) groups on the surface of the spermatozoa, likely due to oxidation caused by the PFAS. Administering d-Pen also reversed this effect, suggesting a possible involvement of S-S bond formation during spermatozoa agglutination. These findings not only shed light on how PFOS and PFOA affect boar spermatozoa capacitation, but also shows the mechanism associated with spermatozoa rosette-type agglutination provoked by PFOS and PFOA. Furthermore, they underscore the need to delve more deeply into the mechanisms that govern agglutinate formation during spermatozoa capacitation physiology to devise improved, targeted therapeutic strategies for male infertility and enhance animal reproduction.

Per- and polyfluoroalkyl substances as persistent pollutants with metabolic and endocrine-disrupting impacts

The widespread use of per- and polyfluoroalkyl substances (PFASs), and their resistance to degradation, renders human exposure to them inevitable. PFAS exposure disturbs endocrine function, potentially affecting cognitive development in newborns through thyroid dysfunction during pregnancy. Recent studies reveal varying male and female reproductive toxicity across PFAS classes, with alternative analogs affecting sperm parameters and legacy PFASs correlating with conditions like endometriosis. Metabolically, PFASs exposure is linked to metabolic disorders, including obesity, type 2 diabetes mellitus (T2DM), dyslipidemia, and liver toxicity, particularly in early childhood. This review focuses on the endocrine-disrupting impact of PFASs, particularly on fertility, thyroid, and metabolic functions. We highlight the complexity of the PFAS issue, given the large number of molecules and their extremely diverse mixed effects.

Per- and polyfluoroalkyl substances (PFAS) accumulation in fish occupying different trophic positions from East Canyon Creek, a seasonally effluent-dominated river, Utah, USA

Fish and seafood are considered a major source of human dietary exposure to per- and polyfluoroalkyl substances (PFAS). In this study, we examined levels of 35 PFAS in fish samples of brown trout and mottled sculpin, which occupy different trophic positions, collected in 2014 from East Canyon Creek in Utah, USA. We observed 20 PFAS with ∑20PFAS ranging from 0.46-63.9 ng/g and from Collapse

Key Words

• Bioaccumulation
• Fish
• Food safety
• PFAS
• Trophic position

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MESH Headings

• Animals
• Utah
• Water Pollutants, Chemical/metabolism
• Water Pollutants, Chemical/analysis
• Fluorocarbons/metabolism
• Fluorocarbons/analysis
• Environmental Monitoring
• Rivers/chemistry
• Food Chain
• Fishes/metabolism
• Trout/metabolism

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Grants Collapse

Affiliation(s)

Yelena Sapozhnikova USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA, USA.
Kevin M Stroski USDA, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA, USA; Center for Reservoir and Aquatic Systems Research, Department of Environmental Science, Baylor University, Waco, TX, USA
Samuel P Haddad Center for Reservoir and Aquatic Systems Research, Department of Environmental Science, Baylor University, Waco, TX, USA
S Rebekah Burket Center for Reservoir and Aquatic Systems Research, Department of Environmental Science, Baylor University, Waco, TX, USA
Michael Luers Snyderville Basin Water Reclamation District, Park City, UT, USA
Bryan W Brooks Center for Reservoir and Aquatic Systems Research, Department of Environmental Science, Baylor University, Waco, TX, USA

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Collaborators Collapse

Associations between per- and polyfluoroalkyl substances (PFAS) and female sexual function in a preconception cohort

BACKGROUND

Female sexual function is important for sexual well-being, general health, fertility, and relationship satisfaction. Distressing impairments in sexual function, clinically recognized as female sexual dysfunction (FSD), can manifest as issues with interest/desire, arousal, orgasm, and pain during vaginal penetration. Some evidence suggests that exposure to endocrine-disrupting chemicals may adversely affect female sexual function, but associations for per- and polyfluoroalkyl substances (PFAS) have not been previously evaluated.

OBJECTIVE

We investigated associations between serum PFAS concentrations and female sexual function among U.S. pregnancy planners.

METHODS

We used cross-sectional data from participants from Pregnancy Study Online (PRESTO), a prospective preconception cohort study. Participants reported sexual function and distress at baseline on two validated measures: a modified version of the Female Sexual Function Index-6 (FSFI-6) and the Female Sexual Distress Scale (FSDS). We quantified PFAS serum concentrations in samples collected in the preconception period (i.e., at baseline) using solid phase extraction-high performance liquid chromatography-isotope-dilution-mass spectrometry. Participants reported sociodemographic information on structured baseline questionnaires. We included 78 participants with complete PFAS and sexual function data and fit multivariable linear regression models to estimate mean differences in FSFI-6 scores (β) or percent differences (%) in FSDS scores per interquartile range (IQR) increase in PFAS concentrations, adjusting for age, annual household income, years of education, parity, and body mass index. We further investigated effect measure modification by parity (parous vs. nulliparous) in stratified models.

RESULTS

An IQR increase in perfluorohexanesulfonic acid was associated with a 1.0-point decrease (95% CI = -1.8, -0.1) in reported FSFI-6 scores, reflecting poorer sexual function. PFAS were consistently associated with lower FSFI-6 scores among parous participants. PFAS were also associated, though imprecisely, with greater sexual distress.

CONCLUSION

Some PFAS were associated with poorer sexual function among U.S. pregnancy planners, but future studies are needed to clarify the extent to which PFAS influences female sexual health.

Real-time wastewater quality monitoring by fluorescence sensors: Validation for COD and CEC monitoring and implication for carbon footprint reduction

This study investigated the applicability of a protein-like fluorescence sensor for wastewater quality monitoring. Several wastewater matrices, including raw, primary, secondary and tertiary effluents from three different wastewater treatment plants were used. Furthermore, the sensor was tested for the monitoring of quaternary effluent in a pilot scale plant installed downstream of a water reuse facility. The pilot plant involved advanced oxidation processes (AOPs) and granular activated carbon (GAC) adsorption. Corrections on excitation/emission matrices (EEMs), including Inner Filter Effect (IFE) and scattering, showed no effect on linear correlation (R2=0.99) between sensor measurement and either raw or corrected benchtop protein-like fluorescence data, suggesting that for this application the signal from the sensor might be interpreted without the need for further adjustments. Furthermore, the use of quenched, diluted and filtered samples did not affect such correlations. Overall, the fluorescence sensor showed a very high capability to monitor a wide range of wastewater matrices, including raw, primary, secondary, tertiary, and quaternary effluents, providing fast information on the efficiency of the processes. The protein-like fluorescence monitoring by the real-time sensor was validated online through 9 days of 24-hour continuous monitoring of tertiary wastewater effluents. The employed fluorescence sensor was validated for monitoring the removal of contaminants of emerging concern (CEC), including a wide range of pharmaceuticals, in different AOP systems (ozone and UV based). In view of the results reported in this study, possible environmental implications for the reduction of the carbon footprint have emerged: the use of fluorescence sensors may contribute to the optimization of processes and the reduction of secondary pollution.

PFAS (per- and polyfluorinated alkyl substances) as EDCs (endocrine-disrupting chemicals) - Identification of compounds with high potential to bind to selected terpenoids NHRs (nuclear hormone receptors)

The objective of the subsequent study was to examine the probability of PFAS (per- and polyfluorinated alkyl substances) binding to various NHRs (nuclear hormone receptors) and to identify their structural features that contribute most to the binding score (BS). We evaluated the BS for PFAS in relation to 7 selected NHRs - 4 with additional antagonist forms (Retinoid X receptor alpha - RXRα, Liver X receptor alpha - LXRα, Liver X receptor beta - LXRβ, Estrogen receptor alpha - ERα, Estrogen receptor alpha antagonist - anti-ERα, Estrogen receptor beta - ERβ, Estrogen receptor beta antagonist - anti-ERβ, Glucocorticoid receptor - GR, Glucocorticoid receptor antagonist - anti-GR, Androgen receptor - AR, Androgen receptor antagonist - anti-AR). We based our study on the results of molecular docking, which we used to develop MLR-QSAR (Multiple Linear Regression - Quantitative Structure-Activity Relationship) models. The models we developed allowed us to predict the BS for an extensive set of PFAS compounds from the NORMAN database (more than 4000) - virtual screening. The probability of PFAS binding to selected receptors was determined by structural features such as particle size, branching, and fluorine content. These variables were also identified in the literature reports of experimental studies as the most important for this group of compounds. The research focused on receptors from the terpenoid group. The RXRα, LXRα and β, GR, and anti-GR receptors were shown to be the group less likely to be affected by PFAS. Sex hormones such as AR, anti-AR, ERα and ERβ with their antagonist forms are the most affected.

Effects of Early-life PFAS Exposure on Child Neurodevelopment: A Review of the Evidence and Research gaps

PURPOSE OF REVIEW

Per- and polyfluoroalkyl substances (PFAS) are persistent chemicals with many modern applications, leading to widespread contamination and universal human exposure. PFAS exposure during early life is of particular concern, given susceptibility of the developing fetal and infant brain to toxic exposures. This review aims to synthesize current evidence, discuss methodological challenges, and highlight research gaps to guide future studies on the impact of PFAS on neurodevelopment.

RECENT FINDINGS

Sixty-one studies in total were published from 2008 to March 2024, with 35 in the last five years. Findings primarily link early life PFAS exposure to reduced cognitive, motor, and language development in infancy and increased behavioral issues like hyperactivity in childhood. Large studies have shown mixed results concerning child cognition, executive function, autism, and ADHD, with some indicating no association or unexpected protective findings. Sex-specific associations have been observed, but not consistently. Most research has addressed low-level exposure, suggesting subtle but potentially significant population-wide neurodevelopmental effects. Recent research also highlights concerns about newer, alternative PFAS, suggesting they too might affect neurodevelopment.  The effects of early-life PFAS exposure on neurodevelopment merit further study, particularly the cumulative effects of prenatal and postnatal exposures. Research has not fully explored sensitive subgroups or potential mitigating factors such as breastfeeding and nutrient intake, which will require larger, more diverse samples. Future directions include deeper study of PFAS mixtures, interactions with other neurotoxic environmental chemicals, and effects of newer PFAS types. There is also a need to focus on neuropsychological functioning in later childhood, using direct assessments for more reliable evaluations.

Per- and Polyfluoroalkyl Substances and Female Health Concern: Gender-based Accumulation Differences, Adverse Outcomes, and Mechanisms

The deleterious health implications of perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widely recognized. Females, in contrast to males, exhibit unique pathways for PFAS exposure and excretion, leading to complex health outcomes. The health status of females is largely influenced by hormone-related processes. PFAS have been reported to be associated with various aspects of female health, including reproductive system disorders and pregnancy-related diseases. In this article, we provide insights into the correlations between PFAS and female-prevalent diseases. Current epidemiological and toxicological evidence has demonstrated that the adverse effects of PFAS on the health of the female reproductive system are primarily attributed to the disruption of the hypothalamic-pituitary-gonadal (HPG) axis and hormonal homeostasis. However, these findings do not sufficiently elucidate the intricate associations between PFAS and specific diseases. Furthermore, autoimmune disorders, another category that is more prevalent in women compared to men, require additional investigation. Immune biomarkers pertinent to autoimmune disorders have been observed to be influenced by PFAS exposure, although epidemiological evidence is insufficient to substantiate these relations. Further thorough exploration encompassing epidemiological and toxicological studies is essential to elucidating the inherent influence of PFAS on human pathologies. Additionally, comprehensive investigations into female health issues beyond their reproductive functions is essential.

Enzymatic Degradation of PFAS: Current Status and Ongoing Challenges

Per- and polyfluoroalkyl substances (PFAS) are often considered the quintessential example of industrial chemical pollution - they are toxic and ubiquitous environmental contaminants that are extremely difficult to degrade. There has been a large research focus on the development of effective and renewable degradation technologies. In comparison to traditional pollutant degradation techniques, such as advanced oxidation processes and electrochemistry, degradation of PFAS using extracellular enzymes offers an eco-friendly solution as enzymes are biodegradable, recyclable and have low energy and chemical requirements. This review outlines the current understanding of extracellular enzymatic degradation of PFAS with a focus on reported results and proposed degradation mechanisms. More importantly, this review highlights limitations that hinder the application of enzymes for PFAS degradation and proposes critical future research that is needed to improve the applicability of this promising remediation strategy.

Prenatal exposure to phthalates and phthalate replacements in relation to chorionic plate surface vasculature at delivery

Pregnant people are ubiquitously exposed to endocrine-disrupting phthalates through consumer products and food. The placenta may be particularly vulnerable to the adverse effects of phthalates, with evidence from animal models suggesting impacts on placental development and vascularization. We translate this research to humans, examining gestational exposure to phthalates and phthalate replacements in relation to novel markers of chorionic plate surface vascularization. Phthalate and phthalate replacement metabolites were measured in first trimester urine from pregnant participants in the Understanding Pregnancy Signals and Infant Development (UPSIDE) cohort (n = 154). At delivery, placentae underwent specialized 2D and 3D digital imaging to quantify chorionic plate surface vasculature. Using weighted quantile g-computation mixtures methods as well as multivariable linear regression models examining individual metabolites, we evaluated associations with overall chorionic plate surface area and five chorionic plate surface vascular measures, adjusting for covariates. We additionally examined interactions with placental sex. Exposure to a phthalate mixture was associated with longer total arterial arc length (β = 9.64 cm; 95%CI: 1.68, 17.59), shorter mean arterial arc length (β = -0.07 cm; 95%CI: -0.14, -0.01), and more arterial branch points (β = 5.77; 95%CI: 1.56, 9.98), but not chorionic plate surface area. In models considering individual metabolites and their molar sums, results were strongest for the metabolites of Di-isobutyl phthalate (DiBP), Di-isononyl phthalate (DiNP), and Di(2-ethylhexyl) phthalate (DEHP). Associations with metabolites of phthalate replacements tended to be in the same direction but weaker. Few sex differences were observed. Gestational phthalate exposure may be associated with alterations in placental chorionic plate surface vasculature characterized by more branching and shorter segments. These alterations may have implications for placental perfusion and suggest a placental mechanism by which phthalates may impact fetal development.

Triglycerides mediate the relationships of per- and poly-fluoroalkyl substance (PFAS) exposure with nonalcoholic fatty liver disease (NAFLD) risk in US participants

Nonalcoholic fatty liver disease (NAFLD) is recognized as a significant public health problem worldwide. Several clinical studies have investigated the associations between Per- and poly-fluoroalkyl substances (PFAS) compounds with the risk of NAFLD in general adults, but the mediating effect of triglycerides (TG) was remained unexplored. In this study, 6990 individuals from the National Health and Nutrition Examination Survey (NHANES, 2003-2018) database were enrolled. Firstly, the results of generalized linear models (GLM) and restricted cubic splines (RCS) revealed positive associations of PFAS compounds with NAFLD risk score and liver function, and nearly linear E-R curves indicated no safe threshold. Meanwhile, weighted quantile sum (WQS) regression demonstrated the relationships between PFAS mixtures with NAFLD risk score and liver function, as well as perfluorooctanoic acid (PFOA) was identified as the main contributor to the increased NAFLD risk. Then, mediation analysis was conducted to explore whether serum lipids mediate the relationships. It further highlighted significant mediation effects of TG, with the mediated proportion ranging from 10.4 % to 42.9 %. Finally, sensitivity and stratified analyses were performed, confirming the reliability of these findings. Notably, significant associations were observed in individuals with a BMI ≥ 28, highlighting that these relationships were particularly evident in obese participants. In conclusion, our study suggested that PFAS mixtures exposure may influence NAFLD risk score by mediating TG in human metabolism. This result could provide more comprehensive epidemiological evidence and guide clinical applications.

PFAS and menopause onset: Is it just a matter of reverse causation? Cross-sectional and longitudinal analyses in highly exposed women in the Veneto Region

INTRODUCTION

Several cross-sectional studies have linked perfluoroalkyl substances (PFAS) to prevalence of menopause. These findings might be influenced by reverse causation mechanism, making longitudinal studies more suitable. However, existing longitudinal studies are limited and present conflicting results.

AIM

This study investigates the association between PFAS and both prevalence and incidence of menopause, using longitudinal designs to limit the impact of reverse causation.

METHODS

A surveillance program on a PFAS highly exposed population in the Veneto region started in 2017 with two rounds of screening, on average 3.8 years apart. Women who participated in the first screening (n = 11,046) were included in the cross-sectional analysis. Multivariate logistic regression models were used to estimate the Odds Ratios (ORs) of menopause associated with exposure to different PFAS. For incidence analysis a retrospective-prospective design used PFOA concentrations reconstructed to 2013 (n = 8536), and a prospective design involved women participating in both screenings (n = 1709), evaluating their baseline concentrations of PFOA, PFOS, and PFHxS. Cox proportional hazards models with age as the timescale were used to estimate Hazard Ratios (HRs), adjusting for sociodemographic and lifestyle factors.

RESULTS

Increased menopause prevalence was associated with higher ln-concentrations of PFOA, PFOS, and PFHxS, with ORs of 1.31 (CI: 1.25-1.38), 1.51 (CI: 1.38-1.66), and 1.42 (CI: 1.34-1.51), respectively. The retrospective-prospective study showed increased risk of menopause in higher PFOA reconstructed quartiles, with HRs of 1.01 (CI: 0.87-1.18), 1.17 (CI: 1.02-1.37), and 1.07 (CI: 0.93-1.23) for the second, third and fourth quartiles. The prospective longitudinal study found no association between PFAS and menopause onset.

CONCLUSIONS

Our results showed a strong cross-sectional association between PFAS exposure and menopause, a weak positive association in the retrospective-prospective study, and no association in the prospective study. This suggests that cross-sectional associations may largely result from reverse causality due to early menopause on reducing PFAS excretion.

Association of perfluoroalkyl substances (PFAS) with liver function biomarkers in the highly exposed population of the veneto region

INTRODUCTION

Epidemiological studies highlight the presence of associations between per- and polyfluoroalkyl substances (PFAS) exposure with liver damage. In 2013, PFAS contamination was discovered in Veneto (Italy), leading to the implementation of a Surveillance Program (SP). Our objective is to investigate the association between PFAS exposure and biomarkers of liver function using single-pollutant and mixture approaches, while exploring the sex-specific differences and the mediating role of obesity in the association.

METHODS

The study included 42,094 subjects aged ≥20 years participating in the SP. We used generalized additive models to investigate the association between several PFAS and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, adjusting for possible confounders and stratifying by sex. Results were back-transformed to show predicted percentage changes in outcomes per ln-unit increase in PFAS levels; furthermore, we explored the role of BMI in the abovementioned causal pathway, considering it as a potential confounder or mediator PFAS joint effect was investigated using Quantile G-computation.

RESULTS

One ln-unit increase in PFHxS concentrations was associated with a 1.49% (95%CI: 0.87, 2.12) and a 0.84% (95% CI: 0.27, 1.40) increase in ALT levels, in males and females respectively; one ln-unit increase in PFOA concentrations was associated with a 1.03% (95%CI: 0.50, 1.55) increase in ALT levels in males, and a 0.52% (95% CI: 0.22, 0.82) and a 0.60% (95% CI: 0.25, 0.96) increase in AST levels in females and males. PFOS showed no association with ALT and AST levels. Quantile G-computation revealed that an interquartile increase in the PFAS mixture was associated with a 3.02% increase (95% CI: 1.65, 4.43) and a 1.65% (95% CI: 0.77, 2.5) increase in ALT levels, in females and males. Mediation analysis suggested that BMI suppressed the association between PFAS and ALT levels, with positive direct effects higher than the total effects.

CONCLUSION

Our findings suggest sex-specific associations between PFAS exposure and liver function biomarkers and underscore the need for additional studies on potential mediators.

Neurotoxicity of per- and polyfluoroalkyl substances: Evidence and future directions

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals widely used in various products, including food packaging, textiles, and firefighting foam, owing to their unique properties such as amphiphilicity and strong CF bonds. Despite their widespread use, concerns have arisen due to their resistance to degradation and propensity for bioaccumulation in both environmental and human systems. Emerging evidence suggests a potential link between PFAS exposure and neurotoxic effects, spanning cognitive deficits, neurodevelopmental disorders, and neurodegenerative diseases. This review comprehensively synthesizes current knowledge on PFAS neurotoxicity, drawing insights from epidemiological studies, animal experiments, and mechanistic investigations. PFAS, known for their lipophilic nature, tend to accumulate in lipid-rich tissues, including the brain, breaching biological barriers such as the blood-brain barrier (BBB). The accumulation of PFAS within the central nervous system (CNS) has been implicated in a spectrum of neurological maladies. Neurotoxicity induced by PFAS manifests through a multitude of direct and indirect mechanisms. A growing body of research associated PFAS exposure with BBB disruption, calcium dysregulation, neurotransmitter alterations, neuroinflammation, oxidative stress, and mitochondrial dysfunction, all contributing to neuronal impairment. Despite notable strides in research, significant lacunae persist, necessitating further exploration to elucidate the full spectrum of PFAS-mediated neurotoxicity. Prospective research endeavors should prioritize developing biomarkers, delineating sensitive exposure windows, and exploring mitigation strategies aimed at safeguarding neurological integrity within populations vulnerable to PFAS exposure.

Per- and poly-fluoroalkyl substances (PFAS) accelerate biological aging mediated by increased C-reactive protein

Unhealthy biological aging is related to higher incidence of varied age-related diseases, even higher all-cause mortality. Previous small sample size study suggested that Per- and poly-fluoroalkyl substances (PFAS) was associated with biological aging, but the evidence of exposure-response relationships, potential effect modifiers, and potential mediators were not investigated. Therefore, we conducted a cross-sectional analysis of national study including 14, 865 adults in the US from 8 survey cycles of NHANES from 2003 to 2018, to investigate the associations of PFAS compounds in body serum, including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS), with biological aging. Generalized linear models showed that higher human exposure to PFAS was associated with accelerated biological aging. Importantly, human exposure to PFOA, PFOS, PFNA, and PFHxS with detected level (above 0.10 ng/mL) was associated with an average of 3.3 year (95 %CI: 2.7, 3.9, P < 0.001), 14.9 year (95 %CI: 7.2, 22.7, P < 0.001), 10.9 years (95 %CI: 3.9, 17.7, P < 0.001), and 8.8 years (95 %CI: 4.8, 12.9, P < 0.001) of biological aging acceleration. Cubic spline models indicated exposure-response relationships where there was no safe threshold of PFAS level regarding harms to human healthy aging. The weighted sum regression model found the significant associations of PFAS compound mixture with biological aging acceleration, and PFOA was the dominant contributor among 4 PFAS compounds. Mediation analysis suggested that C-reactive protein, one of the inflammation biomarkers, might play as mediator in PFAS-induced accelerated biological aging, but not Triglyceride-glucose index. In summary, our study suggests that the effects of PFAS on biological aging acceleration should be of concern and more action plans to address their negative impact on human health should be launched.

Environmental Exposure to Per- and Polyfluorylalkyl Substances (PFASs) and Reproductive Outcomes in the General Population: A Systematic Review of Epidemiological Studies

This Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review synthesized effects of background levels of per- and polyfluorylalkyl substance (PFAS) levels on reproductive health outcomes in the general public: fertility, preterm birth, miscarriage, ovarian health, menstruation, menopause, sperm health, and in utero fetal growth. The inclusion criteria included original research (or primary) studies, human subjects, and investigation of outcomes of interest following non-occupational exposures. It drew from four databases (Web of Science, PubMed, Embase and Health and Environmental Research Online (HERO)) using a standardized search string for all studies published between 1 January 2017 and 13 April 2022. Risk of bias was assessed by two independent reviewers. Data were extracted and reviewed by multiple reviewers. Each study was summarized under its outcome in terms of methodology and results and placed in context, with recommendations for future research. Of 1712 records identified, 30 were eligible, with a total of 27,901 participants (33 datasets, as three studies included multiple outcomes). There was no effect of background levels of PFAS on fertility. There were weakly to moderately increased odds of preterm birth with higher perfluorooctane sulfonic acid (PFOS) levels; the same for miscarriage with perfluorooctanoic acid (PFOA) levels. There was limited yet suggestive evidence for a link between PFAS and early menopause and primary ovarian insufficiency; menstrual cycle characteristics were inconsistent. PFAS moderately increased odds of PCOS- and endometriosis-related infertility, respectively. Sperm motility and DNA health were moderately impaired by multiple PFAS. Fetal growth findings were inconsistent. This review may be used to inform forthcoming drinking water standards and policy initiatives regarding PFAS compounds and drinking water. Future reviews would benefit from more recent studies. Larger studies in these areas are warranted. Future studies should plan large cohorts and open access data availability to capture small effects and serve the public. Funding: Great Lakes Water Authority (Detroit, MI), the Erb Family Foundation through Healthy Urban Waters at Wayne State University (Detroit, MI), and Wayne State University CLEAR Superfund Research (NIH P42ES030991).

Per- and polyfluoroalkyl substances (PFAS): Trends in mass spectrometric analysis for human biomonitoring and exposure patterns from recent global cohort studies

Per- and polyfluoroalkyl substances (PFAS) are widespread environmental contaminants that have been shown to contribute to human exposure, thereby raising a range of health concerns. In this context, human biomonitoring is essential for linking exposure levels of PFAS with their potential health risks. Mass spectrometry-based analytical techniques have been extensively adopted for the evaluation of PFAS levels across various cohorts. However, challenges arising from the use of biological samples (e.g., plasma, serum, urine, etc.) necessitate ongoing research and refinement of analytical methodologies. This review provides an overview of current trends in mass spectrometry-based approaches for human biomonitoring of PFAS, including sample collection and preparation, and instrumental techniques. We also explore analytical strategies to overcome challenges in obtaining PFAS-free blank matrices and address the risk of background contamination. Moreover, this review examines differing PFAS exposure patterns across regions by analyzing recent international cohort studies, specifically those conducted in the US and China over the past five years. Accordingly, several key research gaps in biomonitoring studies that need to be addressed moving forward are highlighted.

Predicting the molecular mechanisms of cardiovascular toxicity induced by per- and polyfluoroalkyl substances: an In Silico network toxicology perspective

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are human-made chemicals that accumulate in the human body and the environment over time. Humans are primarily exposed to PFAS through drinking water, food, consumer products, and dust. These exposures can have many adverse health effects, including cardiovascular diseases (CVDs) and factors contributing to CVDs. This study identified the molecular mechanisms of CVDs caused by PFAS.

METHODS

For this purpose, various computational tools, such as the Comparative Toxicogenomic Database, ShinyGO, ChEA3, MIENTURNET, GeneMANIA, STRING, and Cytoscape, were used to conduct in silico analyses.

RESULTS

The results showed that 10 genes were common between PFAS and CVDs, and among these common genes, the PPAR signaling pathway, fatty acid metabolic processes, and lipid binding were the most significantly associated gene ontology terms. Among the top 10 transcription factors (TFs) related to these common genes, peroxisome proliferator-activated receptor gamma and androgen receptor were the most prominent. Additionally, hsa-miR-130b-3p, hsa-miR-130a-3p, and hsa-miR-129-5p were featured microRNAs involved in PFAS-induced CVDs. Finally, PPARA and PPARG were identified as core genes involved in PFAS-induced CVDs.

CONCLUSION

These findings may contribute to a better understanding of the molecular mechanisms and reveal new potential targets in PFAS-induced CVDs.

The effects of perfluorooctanoic acid on breast cancer metastasis depend on the phenotypes of the cancer cells: An in vivo study with zebrafish xenograft model

Per- and polyfluorinated substances (PFAS) have been associated with numerous human diseases. Recent in vitro studies have implicated the association of PFAS with an increased risk of breast cancer in humans. This study aimed to assess the toxic effects of PFAS during the development of human breast cancer using a zebrafish xenograft model. Perfluorooctanoic acid (PFOA) was used as a PFAS chemical of interest for this study. Two common breast cancer cell lines, MCF-7 and MDA-MB-231, were used to represent the diversity of breast cancer phenotypes. Human preadipocytes were co-implanted with the breast cancer cells into the zebrafish embryos to optimize the microenvironment for tumor cells in vivo. With this modified model, we evaluated the potential effects of the PFOA on the metastatic potential of the two types of breast cancer cells. The presence of human preadipocytes resulted in an enhancement to the metastasis progress of the two types of cells, including the promotion of cell in vivo migration and proliferation, and the increased expression levels of metastatic biomarkers. The enhancement of MCF-7 proliferation by preadipocytes was observed after 2 days post injection (dpi) while the increase of MDA-MB-231 proliferation was seen after 6 dpi. The breast cancer metastatic biomarkers, cadherin 1 (cdh1), and small breast epithelial mucin (sbem) genes demonstrated significant down- and upregulations respectively, by the co-injection of preadipocytes. In the optimized xenograft model, the PFOA consistently promoted cell proliferation and migration and altered the metastatic biomarker expression in MCF-7, which suggested a metastatic effect of PFOA on MCF-7. However, those effects were not consistently observed in MDA-MB-231. The presence of the preadipocytes in the xenograft model may provide a necessary microenvironment for the progress of tumor cells in zebrafish embryos. The finding suggested that the impacts of PFOA exposure on different phenotypes of breast cancers may differ.

Transplacental transfer of perfluorinated and poly-fluorinated substances in maternal-cord serum and association with birth weight: A birth cohort study, China

Although the effects of traditional perfluorinated and polyfluorinated substances (PFASs) exposure have been extensively explored, research on novel PFASs remains limited, and there is a lack of data regarding their placental transfer and fetal impact. Herein, we aimed to examine maternal and fetal PFASs exposure levels, placental transfer efficiency (TTE), and the consequences of prenatal exposure on birth weight. The study included 214 mother-child pairs recruited in Wuxi birth cohort from 2019 to 2021. Twenty-three PFASs were quantified in maternal serum during the second trimester and umbilical serum during delivery. Median concentrations of ∑23PFASs in maternal and cord sera were 9.34 and 6.88 ng/mL, respectively. The novel alternatives exhibited elevated levels of maternal and fetal exposure, such as perfluorovaleric acid (PFPeA, 2.00 ng/mL and 1.66 ng/mL, respectively) and perfluorohexane sulfonate (PFHxS, 1.77 and 1.14 ng/mL, respectively). With increasing carbon chain length, the TTE of perfluorocarbonic acid (PFCAs) displayed a pattern of initially decreasing before subsequently increasing, with novel alternatives exhibiting a relatively high TTE. Multiple linear regression showed that exposure to perfluorobutane sulfonate (PFBS) and PFPeA in cord serum positively correlated with the birth weight of female infants (β = 231.04 g, 95% confidence interval [CI]: 21.73-440.36; β = 121.26 g, 95% CI: 29.51-213.00). No nonlinear relationship was observed between cord serum PFASs and birth weight. The weighted quantile sum (WQS) regression analysis has reaffirmed that PFPeA and PFBS were predominant contributors to the positive correlation observed between the mixture of PFASs and birth weight. Our findings suggest that novel PFASs may exhibit a heightened susceptibility for transplacental transfer and that exposure to PFBS and PFPeA during pregnancy could be linked to increased birth weight.

In vitro and in silico characterization of the transport of selected perfluoroalkyl carboxylic acids and perfluoroalkyl sulfonic acids by human organic anion transporter 1 (OAT1), OAT2 and OAT3

Perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) belong to the group of poly- and perfluoroalkyl substances (PFASs), which may accumulate in humans due to their limited excretion. To provide more insights into the active renal excretion potential of PFASs in humans, this work investigated in vitro the transport of three PFCAs (PFHpA, PFOA, PFNA) and three PFSAs (PFBS, PFHxS and PFOS) using OAT1-, OAT2- or OAT3-transduced human embryonic kidney (HEK) cells. Only PFHpA and PFOA showed clear uptake in OAT1-transduced HEK cells, while no transport was observed for PFASs in OAT2-transduced HEK cells. In OAT3-transduced HEK cells only PFHpA, PFOA, PFNA, and PFHxS showed clear uptake. To study the interaction with the transporters, molecular docking and dynamics simulations were performed for PFHpA and PFHxS, for which a relatively short and long half-lives in humans has been reported, respectively. Docking analyses could not always distinguish the in vitro transported from the non-transported PFASs (PFHpA vs. PFHxS), whereas molecular dynamic simulations could, as only a stable interaction of the PFAS with the inner part of transporter mouth was detected for those that were transported in vitro (PFHpA with OAT1, none with OAT2, and PFHpA and PFHxS with OAT3). Altogether, this study presents in vitro and in silico insight with respect to the selected PFASs transport by the human renal secretory transporters OAT1, OAT2, and OAT3, which provides further understanding about the differences between the capability of PFAS congeners to accumulate in humans.

Association between PFAS exposure and thyroid health: A systematic review and meta-analysis for adolescents, pregnant women, adults and toxicological evidence

A burgeoning body of epidemiological and toxicological evidence suggests that thyroid health may be significantly impacted by exposure to both long- and short-chain perfluoroalkyl substances (PFAS) compounds. We conducted a meta-analysis to examine the association between 16 PFAS compounds and five thyroid hormones (TSH, TT3, TT4, FT3, and FT4) in the serum of a pregnant women, adolescents, and adults. The dose-response relationship between some PFAS and thyroid hormones in different population subpopulation was found and the model was fitted. We also amalgamated data from 18 animal experiments with previously published in vitro studies to elucidate the toxicological mechanisms underlying the impact of PFAS on the thyroid gland. The results of the study showed that (a) both conventional and emerging PFAS compounds were identified in human samples and exhibited associations with thyroid health outcomes; (b) in animal studies, PFAS have been found to impact thyroid gland health through two primary mechanisms: by influencing the hypothalamic-pituitary-thyroid axis and by binding to thyroid receptors. This study provides a systematic description of the health effects and risk assessment associated with PFAS exposure on the thyroid gland. Furthermore, dose-response relationships were established through the Hill model in python.

Exposure to Per- and Polyfluoroalkyl Substances and Risk of Psoriasis: A Population-Based Study

PFAS are a group of synthetic chemicals that have been reported to be associated with adverse health outcomes. However, the relationship of PFAS exposure with psoriasis risk has not been reported. Utilizing data from the 2003-2018 NHANES, we explored the relationship of PFAS exposure with psoriasis risk. Our study included 5370 participants and examined serum levels of five PFAS compounds: PFOA, PFOS, PFHxS, PFNA, and PFDA, along with self-reported psoriasis status. Generalized linear regression, quantile g-computation, repeated hold out WQS regression, and BKMR models were employed to assess individual and combined effects of PFAS on psoriasis risk. We found each doubling the PFOS concentration was associated with a 19% increased risk of psoriasis (OR: 1.19; 95% CI: 1.01, 1.41) in the overall population. Sex-stratified analyses indicated significant associations between PFOA and PFNA exposure and psoriasis risk in females. Mixture analyses using WQS regression indicated that PFAS mixtures were associated with an 11% increased risk of psoriasis (OR: 1.11, 95% CI: 1.01, 1.22) in females in both the negative and positive direction. BKMR analyses also indicated a positive trend of PFAS mixtures with psoriasis risk in females. Our findings indicate a possible association between PFAS exposure and psoriasis risk, particularly in females.

An inhalation exposure assessment of Hexafluoroisobutylene in pregnant rats

Hexafluoroisobutylene (HFIB) is an important compound widely used in semiconductor lithography materials, refrigerants, fluorine coatings, and pharmaceutical intermediates in the fluorination industry. Owing to its toxicity, the occupational exposure in the workplace, especially for pregnant woman is the concern and there is still lack of the data of HFIB toxicity on pregnancy and fetal development. Here, for the first time, we investigated the effects of HFIB on pregnant rats and fetal development. The pregnant rats were exposed to different doses of HFIB (0 ppm, 27.2 ppm, 53.5 ppm, 105.6 ppm) via whole-body inhalation for the period of organogenesis, which from implantation (gestation day 5) to the day prior to scheduled caesarean section (gestation day 19). The results showed that the pregnant rats exposed to 105.6 ppm HFIB displayed systemic toxicity, including a decrease in body weight and food consumption, as well as tracheal inflammation, pulmonary interstitial inflammation and renal tubular swelling. Moreover, reduced fetal and placental weights, delayed ossification, and a reduced number of ossification centers were observed in fetuses delivered by pregnant rats exposed to 105.6 ppm. These effects were attributed to severe maternal weight loss. In addition, it would be useful to note that no whole-body, visceral or skeletal congenital malformations were observed. However, HFIB exposure at 53.5 ppm showed no significant adverse effects on pregnant rats and fetuses. These findings demonstrate that 105.6 ppm HFIB is a toxic concentration, while 53.5 ppm HFIB is the no-observed-adverse-effect concentration (NOAEC) for both pregnancy and fetal development. This study for the first time to provide evidence for the health risk of HFIB exposure on pregnancy and fetal development.

Innovative techniques for combating a common enemy forever chemicals: A comprehensive approach to mitigating per- and polyfluoroalkyl substances (PFAS) contamination

The pervasive presence of per and polyfluoroalkyl substances (PFAS), commonly referred to as "forever chemicals," in water systems poses a significant threat to both the environment and public health. PFAS are persistent organic pollutants that are incredibly resistant to degradation and have a tendency to accumulate in the environment, resulting in long-term contamination issues. This comprehensive review delves into the primary impacts of PFAS on both the environment and human health while also delving into advanced techniques aimed at addressing these concerns. The focus is on exploring the efficacy, practicality, and sustainability of these methods. The review outlines several key methods, such as advanced oxidation processes, novel materials adsorption, bioremediation, membrane filtration, and in-situ chemical oxidation, and evaluates their effectiveness in addressing PFAS contamination. By conducting a comparative analysis of these techniques, the study aims to provide a thorough understanding of current PFAS remediation technologies, as well as offer insights into integrated approaches for managing these persistent pollutants effectively. While acknowledging the high efficiency of adsorption and membrane filtration in reducing persistent organic pollutants due to their relatively low cost, versatility, and wide applicability, the review suggests that the integration of these methods could result in an overall enhancement of removal performance. Additionally, the study emphasizes the need for researcher attention in key areas and underscores the necessity of collaboration between researchers, industry, and regulatory authorities to address this complex challenge.

Destruction of Per- and Polyfluoroalkyl Substances in Reverse Osmosis Concentrate Using UV-Advanced Reduction Processes

UV-advanced reduction processes (UV-ARP), characterized by the strongly reducing aqueous electron (eaq -), have been shown to degrade perfluoroalkyl and polyfluoroalkyl substances (PFAS). Due to the high cost of PFAS destruction technologies, concentrated waste streams derived from physical treatment processes, such as ion exchange or membrane concentrates, are promising targets for implementation of these technologies. However, there are limited studies on the application of UV-ARP for PFAS destruction in concentrated waste streams. This study evaluates the effectiveness of the UV/sulfite ARP in reverse osmosis concentrate (ROC) containing high concentrations of dissolved organic carbon (DOC), nitrate, and carbonate species, spiked with mg/L concentrations of perfluorooctanesulfonic acid, perfluorobutanesulfonic acid, perfluorooctanoic acid, and perfluorobutanoic acid. We demonstrate that hardness removal and preoxidation of ROC with UV/persulfate enables >90% PFAS defluorination within 24 h of subsequent UV/sulfite treatment, a 3-fold enhancement in defluorination % compared to UV/sulfite treatment without preoxidation. This enhancement is shown to result from abatement of the light shielding and eaq - scavenging capacity of DOC during UV/persulfate oxidation. Collectively, these results demonstrate that appropriate pretreatment steps increase the effectiveness of PFAS destruction using UV-ARP, supporting the application of UV-ARP for PFAS destruction in ROC and other concentrated waste streams.

Towards a universal model for the foaming behavior of surfactants: a case study on per- and polyfluoroalkyl substances (PFAS)

Foam fractionation offers a promising solution for the separation of surface-active contaminants from water. Therefore, this work aims to comprehensively investigate foaming behavior and its correlations with the interfacial properties. As a case study, we evaluate foaming of per- and polyfluoroalkyl substances (PFAS), which are one of significant environmental issues worldwide due their pervasive presence in the environment. Since there is no universal model to describe the foaming behavior of surfactants that can be applied to PFAS, this research utilizes dimensional analysis to establish a correlation between the foaming behavior of PFAS solutions-characterized by expansion rate of foaming-and dimensionless numbers that represent both processing and interfacial characteristics. Foaming parameters, such as gas flow rate and aeration time, are varied to study their effect on PFAS foamability. In addition, we study PFAS with different headgroups and with different chain lengths in the presence of electrolytes with different concentrations. Our study elucidates distinct, condition-specific equations for individual PFAS, revealing that long-chain PFAS foaming is significantly influenced by interfacial property-related dimensionless numbers, such as the Boussinesq number. Additionally, the Froude number and Weber number affect the foamability of both long- and short-chain PFAS. Moreover, our study identifies specific trends, including a maximum foaming capacity at a certain Capillary number, aligning with the maximum in dilatational interfacial modulus. The results suggest more studies are needed on bubble interaction and foam film behavior.