Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water

Polystyrene nanoplastics amplify the toxic effects of PFOA on the Chinese mitten crab (Eriocheir sinensis)

Nanoplastics (NPs), the final form of degraded microplastics in the environment, can adsorb PFOA (an emerging organic pollutant in recent years) in several ways. Current research on these has focused on bony fishes and mollusks, however, the combined toxicity of PFOA and NPs remains unknown in Eriocheir sinensis. Therefore, the effects of single or combined exposure to PFOA and NPs were investigated. The results showed that NPs aggravated PFOA exposure-induced oxidative stress, serum lipid disorders, immune responses, and morphological damage. DEGs altered by NPs-PFOA exposure were predominantly enriched in GO terms for cell lumen, and organelle structure, and KEGG terms for spliceosome and endocrine disorders-related diseases. Notably, the apoptotic pathway plays a central role enriched under different exposure modes. PFOA or NPs-PFOA exposure disrupted the levels of lipids molecules-related metabolites by mediating the glycerophospholipid pathway, and the NPs mediated the ferroptosis pathway to exacerbate PFOA-induced metabolic toxicity. In addition, NPs exacerbated the inflammatory response and metabolic imbalance by mediating Fusobacterium ulcerans in the intestinal. In conclusion, this study provides a valuable reference for the characterization of NPs-PFOA combined pollution and a scientific basis for the development of environmental protection policies and pollution management strategies.

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.

Differential hepatic activation of mouse and human peroxisome proliferator-activated receptor-α by perfluorohexane sulfonate

Exposure of perfluorohexane sulfonate (PFHxS) is associated with hepatomegaly and accumulation of lipids that may be mediated by nuclear receptors like peroxisome proliferator-activated receptor-α (PPARα), constitutive androstane receptor (CAR), or pregnane X receptor (PXR). This study tested the hypotheses that: (i) PFHxS causes changes in liver by activating PPARα, CAR, or PXR, and (ii) there is a species difference in PPARα activity by PFHxS. Wild-type, Ppara-null, and PPARA-humanized mice were fed either a control diet, or one containing 2.2 mg PFHxS/kg diet or 25.8 mg PFHxS/kg diet for either 7 or 28 days, and target gene expression was examined. Relative liver weights were similar after 7 days with either 2.2 or 25.8 mg PFHxS/kg dietary exposure compared with controls. Relative liver weights were higher after treatment for 28 days in all 3 genotypes fed 25.8 mg PFHxS/kg diet compared with controls. The concentration of PFHxS was dose-dependently increased in serum and liver compared with controls. PFHxS exposure of 2.2 and 25.8 mg PFHxS/kg diet caused an increase in expression of PPARα target genes in wild-type mice and this effect was not observed in similarly treated Ppara-null mice or PPARA-humanized mice. Administration of PFHxS caused increased expression of the CAR target gene Cyp2b10 in all 3 genotypes at both timepoints, and the PXR target gene Cyp3a11 in all 3 genotypes after 28 days. Exposure to PFHxS can increase liver weight due in part to the activation of mouse, but not human, PPARα. Activation of CAR and PXR by PFHxS also likely contributes to the observed hepatomegaly in all 3 genotypes.

Exposure-effect of PFOS and PFOA on lung function: An integrated approach with epidemiological, cellular, and animal studies

Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are increasingly recognized for their adverse impact on human health, particularly on lung function. However, current research results are inconsistent and molecular mechanisms remain unclear, with no studies combining epidemiological, in vivo and in vitro investigations. Our population-based study revealed that PFOS and PFOA exposure is negatively associated with lung function. In vitro, PFOS and PFOA exposure significantly downregulated SP-B mRNA and protein levels, and SP-B expression was restored by overexpression of HSD17B1. PFOS induced hypermethylation and downregulated expression of HSD17B1 in tandem with SP-B. Notably, expression of SP-B was restored after treatment with demethyltransferase inhibitor. In vivo studies corroborated these findings, where PFOS exposure resulted in impaired lung function, histopathological changes, and decreased expression of SP-B and HSD17B1 in lung tissues. Our research demonstrates that PFOS downregulates SP-B expression by inducing hypermethylation and downregulating expression of HSD17B1, leading to impaired lung function.

Longitudinal association of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) exposure with lipid traits, in a healthy unselected population

BACKGROUND

Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) are synthetic substances with long half-lives. Their presence is widespread and pervasive, and they are noted for their environmental persistence. Research has shown these chemicals to be associated with dyslipidaemia, although few studies have considered the long-term associations in the general population.

OBJECTIVES

The aim of this study was to consider the longitudinal and cross-sectional associations with lipid phenotypes.

METHODS

We investigated the association of these chemicals with total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides (TG), and the total cholesterol: high-density lipoprotein ratio (TC:HDL), in a healthy unselected British population of twins (n = 2069), measured at three timepoints between 1996 and 2014.

RESULTS

Serum levels of PFOA and PFOS decreased over time during this period. We demonstrate longitudinal associations across serum levels of both PFOA and PFOS, finding positive associations with TC (PFOA:β = 0.51, p = 1.9e-07; PFOS:β = 0.24, p = 3.8e-05) and LDL (PFOA:β = 0.61, p = 1.7e-11; PFOS:β = 0.42, p = 1.6e-14), and consistent negative associations with HDL and PFOA (β = -0.12, p = 0.003) and PFOS (β = -0.25, p = <2e-16). We also observe cross-sectional associations of PFAS with lipids across all three timepoints.

IMPACT

PFAS remain persistent in the environment, despite regulations, due to their structural properties, leaving humans open to exposure. There is less understanding of how chronic low exposure to these chemicals, particularly within an unselected population, may impact health outcomes. This study reports the longitudinal associations of PFOA and PFOS over an 18-year window with 5 lipid phenotypes, highlighting that despite falling serum levels, PFAS exposure may lead to hyperlipidaemia. We further investigate the cross-sectional associations across three timepoints to understand time-dependent effects, demonstrating associations persist. This work aids our understanding on the long-term effect of chronic PFAS exposure.

Embryonic exposure to GenX causes reproductive toxicity by disrupting the formation of the blood-testis barrier in mouse offspring

As a replacement for perfluorooctanoic acid, hexafluoropropylene oxide dimer acid, commercially referred to as "GenX", has attracted significant attention. However, a comprehensive understanding of the reproductive systems of male offspring exposed to GenX is lacking. This study aimed to investigate how embryonic exposure to GenX affects the reproductive development of male offspring and the underlying mechanisms. We administered GenX daily via gavage (2 mg/kg body weight/day) to the mice from day 12.5 of pregnancy until delivery. Our results suggested that embryonic exposure to GenX led to delayed onset of puberty in male offspring, with destruction of the testicular structure, disruption of the blood-testis barrier, decreased serum testosterone levels, decreased sperm count, impaired sperm motility, and increased rates of sperm abnormalities. We investigated the mechanism of blood-testis barrier breakdown in vitro by treating Sertoli cells (TM4) with GenX. GenX exposure caused the accumulation of senescent TM4 cells, decreased their glutathione (GSH) levels, and increased their oxidized glutathione levels. GenX inhibited glutaminase activity in TM4 cells, leading to decreased GSH synthesis, increased intracellular oxidative stress, and subsequent TM4 cell senescence, ultimately compromising the blood-testis barrier. Our findings indicated that embryonic exposure to GenX may cause Sertoli cell senescence by altering glutamine metabolism, disrupting the blood-testis barrier, and resulting in abnormal reproductive development in male offspring.

Perfluorooctane sulfonic acid: a possible risk factor of endothelial dysfunction based on in silico and in vitro studies

Perfluorooctane sulfonic acid (PFOS) is a fluorinated chemical utilized in a variety of industrial and household products. PFOS has been detected in human serum and is associated with multiple human adverse health effects. Epidemiological evidence has linked PFOS exposure to endothelial dysfunction, which is a key contributor to atherosclerosis. However, the underlying mechanisms of PFOS-induced endothelial dysfunction associated atherosclerosis has not been investigated. In the present study, human microvascular endothelial cells (HMEC-1) exposed to PFOS (15 μM) for 72 h, mimicking long-term exposure. We further employed integrated RNA-sequencing (RNA-seq) and transcriptomic analysis to identify differentially expressed genes (DEGs) for biological alterations: gene ontology (GO), pathway enrichment analysis (KEGG), protein-protein interaction network and modular clustering analysis. Furthermore, the Metascape database was used for disease association, tissue specificity, and transcription factor analysis. Hub genes were verified using atherosclerosis patient data sets from the GEO dataset. Alteration of hub genes in patients was then validated using immunoblotting and ELISA. Our results revealed that PFOS altered amino acid biosynthesis, lipid metabolism and induced the ER-stress response through the HRI/eIF2α/ATF4 pathway, leading to endothelial dysfunction. Interestingly, we found that PFOS induced inflammation by increasing COX-2, ICAM-1 and IL-6 expression through NF-κB and JAK2/STAT3 pathway in endothelial cells. Moreover, up-regulated C/EBPβ and ATF4 were observed in both patients and PFOS-exposed endothelium, which may use as an early biomarker and may have a potential role in PFOS-induced endothelial dysfunction. These findings provide novel insight into the underlying molecular mechanisms of PFOS-induced endothelial dysfunction associated with atherosclerosis.

Perfluorooctanoic acid serum concentrations and half-lives in a community exposed to contaminated drinking water in New York State

BACKGROUND

Investigations during 2014-2016 in two communities in New York State showed perfluorooctanoic acid (PFOA) in a public system serving 3800 residents (Hoosick Falls) averaging 534 ppt and in a smaller system serving 200 residents (Petersburgh) averaging 92.5 ppt. Bottled water (2015-2016) was provided until filtration brought PFOA levels to non-detectable (2016-2017).

OBJECTIVE

The New York State Department of Health (NYSDOH) sought to address community questions about exposures and evaluate reductions in serum concentrations.

METHODS

NYSDOH tested serum PFOA in 2016 just after drinking water exposure mitigation and again in 2018. Descriptive statistics for serum PFOA by sex, age, length of residence, and water consumption were evaluated using multiple regression, and half-lives were estimated.

RESULTS

Using the serum PFOA GM and median for tests occurring within 3 months of exposure mitigation (N = 1121) (47.5, 54.2) produced serum to water ratios of 89.0 and 101.6. A total of 1573 Hoosick Falls public water consumers (337

IMPACT

This biomonitoring project assisted communities with PFOA-contaminated drinking water by providing comparative exposure information and tracking body burden reductions to confirm exposures were minimized. These data are also critical for filling gaps in knowledge about PFOA modes of action and for the conduct of studies that can identify exposure concentrations associated with health risks. The detailed PFOA serum findings described here are being used to construct and validate pharmacokinetic models that will estimate exposures over the lifespan. These findings provide a foundation for PFOA exposure assessment that will benefit the national Multi-Site PFAS Health Study and future studies as well.

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Key Words

• Biomonitoring
• Drinking water contamination
• Half-life
• Perfluorooctane sulfonate (PFOS)
• Perfluorooctanoic acid (PFOA)

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Affiliation(s)

Elizabeth L Lewis-Michl New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA.
Steven P Forand New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA
Wan-Hsiang Hsu New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA
Sanghamitra S Savadatti New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA University at Albany, Department of Epidemiology & Biostatistics, Rensselaer, NY, USA
Ming Liu New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA
June Moore New York State Department of Health, Bureau of Environmental & Occupational Epidemiology, Division of Environmental Health Assessment, Albany, NY, USA
Qian Wu New York State Department of Health, Wadsworth Center, Division of Environmental Health Science, Albany, NY, USA
Elizabeth J Mullin New York State Department of Health, Wadsworth Center, Division of Environmental Health Science, Albany, NY, USA
Kenneth M Aldous New York State Department of Health, Wadsworth Center, Division of Environmental Health Science, Albany, NY, USA

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Characterization of POP mixture redistribution and identification of their molecular signature in xenografted fat mice

Persistent organic pollutants (POPs) are associated with many adverse health effects in humans, including cancers, immune, reproductive, neurological disorders and metabolic diseases. These chemicals are known to accumulate in fatty tissues, from which they can be released in other tissue compartments of living organisms, in particular, upon weight loss. This dynamic distribution of POPs remains, however poorly investigated. In this study, a xenografted POP-contaminated adipose tissue (AT) model was used to assess 1) their concentrations in the ATs, the liver and the brain and 2) their associated effects by transcriptomics, metabolomics and lipidomics approaches. In the ATs, the liver and the brain of mice grafted with POP-contaminated fat pad, most of POPs were detected 3 days and 21 days after the graft with the highest concentrations in the ATs and the lowest concentrations in the brain. Conversely, per- and polyfluoroalkyl substances presented a distinct profile as they persist in the liver but not in the ATs or in the brain. In the AT of POP-exposed mice, the most dysregulated pathways were related to mitochondrial functions, endobiotic (carbohydrate, lipid, amino acid) and xenobiotic metabolism and inflammatory response. In the liver of grafted mice, many pathways related to mitochondrial functions and metabolism were dysregulated. These results support that realistic mixture of POPs that accumulate in AT and liver induces a systemic metabolic dysfunction which may represent the mechanisms by which the POPs can promote metabolic diseases such as obesity, type 2 diabetes and cardiovascular diseases.

Current understanding of human bioaccumulation patterns and health effects of exposure to perfluorooctane sulfonate (PFOS)

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant of global concern due to its environmental presence,bioaccumulative potential and toxicological impacts. This review synthesizes current knowledge regarding PFOS exposure, bioaccumulation patterns and adverse health outcomes in human population. Analysis of worldwide biomonitoring data, and epidemiological studies reveals PFOS systemic effects, including immunological dysfunction (decreased vaccine response), developmental toxicity (reduced birth weight), hepatic metabolic disruption, potential carcinogenogenicity, and reproductive abnormalities. At the molecular level, PFOS induces toxicity through multiple pathways, including PI3K/AKT/mTOR pathway inhibition, PPARα activation, NF-κB signaling modulation, and oxidative stress induction. Recent advances in analytical methodologies have enhanced our understanding of PFOS distribution and fate, while evolving egulatory frameworks attempts to address its risk. This review identifies critical research gaps and emphasized the need for coordinated multidisciplinary approaches to address this persistent environmental contaminant.

Serum concentrations of per- and poly-fluoroalkyl substances (PFAS) in Danish pregnant women-temporal trends during pregnancy, correlations with partners, associations with physical activity, and blood lipid concentrations

BACKGROUND

Per- and polyflouralkyl substances (PFAS) are a group of persistent chemicals used extensively in industries and consumer products due to their water-repellent properties. Studies have linked PFAS exposure to adverse health effects, and human exposure to PFAS, especially during pregnancy, is of great concern. In this study, we report how serum PFAS concentrations during pregnancy correlated with serum PFAS of partners from the same household. Further, we report how serum PFAS concentrations change during the course of pregnancy and associations between PFAS and blood lipid concentrations as well as exploratory analyses of associations between physical activity and PFAS concentrations.

METHODS

In this secondary analysis of data from the FitMum study conducted from 2018 to 2021, 216 healthy, pregnant women, and 110 of their partners were included. Non-fasting venous blood samples were collected from the mothers at three test visits during pregnancy and at delivery, where blood from partners were also collected. Serum samples from all timepoints were analyzed for 15 short- and long-chained PFAS using liquid chromatography triple quadrupole linear ion trap mass spectrometry. Total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and triglyceride blood concentrations were measured at three test visits during pregnancy and at delivery. Physical activity was measured with a wrist-worn activity tracker 24/7 from inclusion before gestational age week 15 + 0 and throughout pregnancy.

RESULTS

In serum samples we detected the following PFAS: PFOS, PFOA, PFHxS, PFNA, PFDA, and PFUnDA. The maternal median concentrations at baseline were: PFOS: 4.09 ng/mL, PFOA: 0.81 ng/mL, PFHxS: 0.29 ng/mL, PFNA: 0.42 ng/mL, PFDA: 0.25 ng/mL, and PFUnDA: 0.19 ng/mL. Partner serum PFAS concentrations were 3-145% higher than maternal concentration (except for PFUnDA). PFAS concentrations correlated within couples. All PFAS decreased significantly during pregnancy (PFOS -23.1 percent 95%-CI [-31.9;-13.2] from baseline to delivery). All PFAS concentrations were associated with increased HDL-C concentrations. No associations between physical activity and maternal PFAS concentrations were found.

CONCLUSIONS

Overall, serum PFAS concentrations decreased during pregnancy. PFAS concentrations within households were strongly correlated. PFAS and HDL-C concentrations were positively associated. We found no associations between physical activity and serum PFAS concentrations.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov; NCT03679130; 20/09/2018.

Per- and polyfluoroalkyl substances (PFAS) exposure in the U.S. population: NHANES 1999-March 2020

Per- and polyfluoroalkyl substances (PFAS), also known as "forever chemicals" because of their persistence in the environment, have been used in many commercial applications since the 1940s. Of late, the detection of PFAS in drinking water throughout the United States has raised public and scientific concerns. To understand PFAS exposure trends in the general U.S. population, we analyzed select PFAS serum concentration data from participants ≥12 years old of nine National Health and Nutrition Examination Survey (NHANES) cycles. Our goals were to a) evaluate concentration changes of four legacy PFAS-perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) from 1999 to 2000 to 2017-March 2020, b) discuss serum concentrations and assess demographic predictors of two PFAS measured for the first time in 2017-2018, perfluoro-1-heptanesulfonic acid (PFHpS) and 9-chlorohexadecafluoro-3-oxanonane-1-sulfonic acid (9CLPF), and c) compare concentration profiles of legacy PFAS in NHANES to profiles in exposed communities. We report a decrease in geometric mean concentrations of the four legacy PFAS (16%-87%, depending on the PFAS) from 1999 to 2000, although in 2017-March 2020, more than 96% of people aged 12-19 years, some of whom were born after PFAS production changes started in the early 2000s, had measurable concentrations of these PFAS. An estimated 78% of the U.S. general population had detectable concentrations of PFHpS, and 8% had detectable concentrations of 9CLPF (>44% of whom self-identified as Asian). Comparing profiles in NHANES and people living in communities with PFAS contamination can help identify exposure sources and evaluate and monitor exposures in select areas or among specific population groups. Collectively, our findings highlight the usefulness of NHANES data to help researchers, public health officials, and policy makers prioritize investigations, monitor exposure changes, and evaluate effectiveness of efforts to limit exposures.

Plasma perfluoroalkyl substances and breast cancer risk in Brazilian women: a case-control study

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants, and have been detected in human blood. Although PFAS may increase the risk of breast cancer in humans, findings from previous epidemiological studies on the link between PFAS and breast cancer are controversial. Additionally, most studies of PFAS to date did not distinguish between isomers. Here, we examined the association of PFAS exposure and breast cancer risk in Brazilian women, who represent a racially and ethnically diverse group.

METHODS

We conducted a case-control study of 471 women with breast cancer and 471 matched controls attending hospitals in São Paulo, Brazil from 2001 to 2006. Plasma concentrations of PFAS congeners were measured using in-port arylation gas chromatography-isotope dilution mass spectrometry with electron capture negative ionization. Linear and branched PFAS isomers were isolated and quantified separately. We derived multivariable-adjusted odds ratios and 95% confidence intervals for breast cancer and hormone-receptor subtypes according to plasma PFAS concentration.

RESULTS

In overall analyses, higher plasma concentrations of n-perfluoroheptane sulfonate (n-PFHpS), perfluoro-3-methyl-heptane sulfonate (3 m-PFOS), and n-perfluorononanoic acid were significantly associated with increased risk of breast cancer. Adjusted odds ratios for low, medium, and high n-PFHpS concentrations were 1.00, 1.28, and 2.00 (95% confidence interval = 1.15, 3.48), respectively (P for trend = 0.015). Furthermore, plasma 3 m-PFOS concentration and total perfluorooctanoic acid concentration were significantly associated with increased risk of breast cancer among mixed-ethnicity women. In Caucasian women, a higher plasma perfluoro-4-methyl-heptane sulfonate concentration was also associated with increased risk of breast cancer. Increased plasma n-PFHpS concentration was significantly associated with higher risk of hormone receptor-positive breast cancer but not with increased risk of hormone receptor-negative breast cancer.

CONCLUSIONS

Several plasma PFAS appear to increase the risk of breast cancer. Our findings suggest the importance of isomer analysis, subgroup analysis by ethnicity, and breast cancer subtype analysis for accurately characterizing this risk.

CLINICAL TRIAL NUMBER

Not applicable.

Association between exposure to per- and polyfluoroalkyl substances and kidney function: a population study

Background

The relationship between per- and polyfluoroalkyl substances (PFAS) and kidney function markers remains uncertain.

Methods

We used PFAS detection data from 5,947 adults in NHANES 2005-2012. We employed multivariable linear regression models to examine associations between PFAS and estimated glomerular filtration rate (eGFR), urine creatinine (UCR), urine albumin (UAL), and urine albumin/creatinine ratio (UACR). To capture non-linear trends, restricted cubic splines were applied. The WQS (weighted quantile sum) and Q-gcomp (quantile g computation) models were used for the mixture analysis. Subgroup analyses were conducted to explore potential interactions.

Results

Perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), 2-(N-methyl-perfluorooctane sulfonamido) acetic acid (N-MEFOSAA), and perfluorononanoic acid (PFNA) were negatively related to eGFR (β = -2.04, 95% CI = -2.85, -1.23; β = -0.97, 95% CI = -1.78, -0.16; β = -1.50, 95% CI = -2.24, -0.76; β = -0.49, 95% CI = -1.25, 0.27; β = -0.68, 95% CI = -1.46, 0.10). PFOA and PFOS were positive associated with UCR (β = 10.61, 95% CI = -1.89, 23.11; β = 12.98, 95% CI = 0.56, 25.41). PFOA, PFOS, PFHxS, PFNA, and PFUA were negatively related to UAL (β = -0.53, 95% CI = -0.73, -0.32; β = -0.39, 95% CI = -0.59, -0.18; β = -0.59, 95% CI = -0.78, -0.40; β = -0.42, 95% CI = -0.65, -0.19; β = -0.04, 95% CI = -0.22, 0.14). PFDA, PFOA, PFOS, PFHxS, and PFNA are significantly inversely associated with UACR (β = -0.01, 95% CI = -0.16, 0.14; β = -0.52, 95% CI = -0.69, -0.35; β = -0.50, 95% CI = -0.67, -0.33; β = -0.49, 95% CI = -0.64, -0.33; β = -0.27, 95% CI = -0.44, -0.10). Nonlinear relationships were found between PFAS and all kidney function indicators. Mixed PFAS exposure showed a negative association with eGFR, UAL and UACR, while showed a positive relationship with UCR. Interactions between PFASs and most subgroups were observed.

Conclusion

Our study revealed significant associations between PFAS exposure and various kidney function indicators. These findings provide an epidemiological perspective on how PFAS may lead to kidney dysfunction.

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.

Prenatal PFAS exposure associates with DXA assessed markers of adiposity in 7-year-old children from the Odense Child Cohort

The global increase in childhood overweight and obesity presents significant public health concerns due to its long-term health implications. Emerging evidence suggests that exposure to endocrine disrupting chemicals, such as per- and polyfluoroalkylated substances (PFAS), may be obesogenic and contribute to adiposity. This study aimed to investigate the association between prenatal PFAS exposure and markers of adiposity in 7-year-old children, focusing on potential sex-specific differences. Data was analyzed from 881 mother-child pairs in the Odense Child Cohort, Denmark. Maternal serum concentrations of perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were measured in early pregnancy. At age 7, body composition, including body mass index (BMI), lean mass and fat distribution (total, gynoid, and android), was assessed using dual-energy X-ray absorptiometry (DXA). The median (25th;75th percentile) concentrations of PFHxS, PFOS, PFOA, PFNA, and PFDA were 0.4 (0.2;0.5), 7.6 (5.6;10.4), 1.7 (1.1;2.3), 0.6 (0.5;0.8), and 0.3 (0.2;0.4) ng/mL, respectively. Multiple linear regressions were used to assess sex specific associations between maternal PFAS concentrations and markers of adiposity. In girls, 1 ng/mL increase in maternal PFOA was associated with 2.0 % (95 % confidence interval: 0.3; 3.7) increase in total fat, 1.3 % (-0.3; 2.9) increase in gynoid fat, and 3.8 % (0.6; 7.0) increase in android fat. Associations for PFNA and PFDA followed similar trends, whereas higher maternal PFOS concentrations were associated with lower BMI among both girls and boys. These findings suggest that prenatal exposure to certain PFAS may influence the accumulation of excess fat in girls. Our findings highlight the importance of studying sex specific differences and using accurate measures of body composition as BMI may not adequately reflect body fat in children during growth.

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.

Common infections in children aged 6 months to 7 years after high prenatal exposure to perfluoroalkyl substances from contaminated drinking water in Ronneby, Sweden

BACKGROUND

Perfluorinated alkyl substances (PFAS) are suggested to impair immune function in children. Previous studies investigating associations between prenatal PFAS exposure and common infections were performed in background-exposed populations whilst studies from high-exposed populations are lacking.

OBJECTIVES

To investigate the association between prenatal PFAS exposure from contaminated drinking water and common infections in children aged 6 months to 7 years in Ronneby, Sweden.

METHODS

The cohort included 17,051 children, born 2003-2013, to mothers residing in Blekinge County at least one year within the five years before childbirth. Primary care diagnoses of infections in eyes, ears, respiratory- and urinary tract were retrieved from the Blekinge Healthcare Register. The residential history of the mothers served as a proxy for prenatal exposure; very high, high, intermediate, and background. We estimated hazard ratios (HR) by Cox proportional hazards regression with the Andersen and Gill extension for recurring events.

RESULTS

We observed an increased risk for ear infections (HR 1.28; 95% CI 1.03-1.58) in children with very high prenatal PFAS exposure, as well as suggestive but non-significant associations with eye- and urinary tract infections. Children with intermediate prenatal exposure had a reduced risk of eye infections (HR 0.86; 95% CI 0.77-0.95). No increased risk of respiratory tract infections was observed in any of the exposure categories.

DISCUSSION

This study was the first to investigate the association between high prenatal PFAS levels and common infections diagnosed in primary care, and it adds to a growing body of evidence of the potential immunotoxicity of early-life PFAS exposure.

Assessment of modeled serum per- and polyfluoroalkyl substances concentrations from exposure estimates for pregnant women in the general population in comparison to previously measured serum concentrations

When drinking water is uncontaminated, exposure to PFAS is thought to occur primarily via ingestion of food and indoor dust. To understand the background exposure during prenatal periods, this study examined whether published estimates of PFAS exposure rates from dietary and dust ingestion provide reasonable predictions of PFAS serum concentrations among pregnant women in the general population. This study estimated serum concentrations of four PFAS during pregnancy based on published PFAS intake rates for food and indoor dust reported in the peer-reviewed literature, a pharmacokinetic model using two different sets of parameters, and Monte Carlo simulation to account for variability/uncertainty. Historical dietary ingestion rate was reconstructed using serum PFAS concentrations of pregnant women from NHANES. The estimated serum concentrations for different exposure scenarios were then compared with measured maternal serum levels reported in published studies of populations without known PFAS water contamination. Mother-child dyad models showed no substantial change in serum PFAS concentrations during pregnancy. Lower published estimates of dietary intake and historical reconstruction, resulted in good prediction of maternal serum concentrations for PFOA, PFOS, and PFHxS. Higher published estimates of dietary intake overestimated maternal serum concentrations, especially for PFNA. Although some discrepancies exist among published estimates of indoor dust intake, half-life, and volume of distribution for PFAS, any combination of selected estimates from literature along with lower published dietary intake estimates are sufficient to provide reasonable prediction of maternal serum concentrations at population-level.

Perfluorohexane Sulfonic Acid Disrupts the Immune Microenvironment for Spermatogenesis by Damaging the Structure of the Blood-Testis Barrier in Mice

Perfluorohexane sulfonic acid (PFHxS) is extensively used in waterproof coatings and fire-fighting foams, and several studies have found it to be a potential health hazard, but there is still unknown about its effects on spermatogenesis. Our results showed that PFHxS-treated mice have significant reproductive toxicity, including a decrease in sperm count and motility, and the levels of sex hormones (P < 0.05). Concurrently, structural abnormalities are observed in sperm, affecting ≈60-75% of those in the PFHxS-treated group. Additionally, it is found that the structure of the blood-testis barrier (BTB) is damaged after PFHxS treatment, leading to higher expression levels of inflammatory cytokines in the microenvironment for spermatogenesis. Moreover, the expression of proteins associated with mitochondrial biogenesis, including PTEN-induced kinase 1 (PINK1) and NADPH oxidase 4 (NOX4), is dysregulated in the testes after PFHxS treatment. Based on metabolome data, the differential metabolite 3-hydroxybutanoic acid is identified in the PFHxS-treated group, which can regulate the histone Kac levels, especially H3K4ac and H3K9ac. In summary, the results of this study suggest that in the testes of PFHxS-treated mice, inflammatory factors disrupt the mitochondrial function and metabolic profiles and hinder the progress of gene transcription through histone Kac, ultimately causing sperm dysfunction.

Hidden link between endocrine-disrupting chemicals and pediatric obesity

The increasing prevalence of pediatric obesity has emerged as a significant public health concern. Among various contributing factors, exposure to endocrine-disrupting chemicals (EDCs) has gained recognition for its potential role. EDCs, including bisphenols, phthalates, per- and polyfluoroalkyl substances, polycyclic aromatic hydrocarbons, and organochlorines, disrupt hormonal regulation and metabolic processes, contributing to alterations in fat storage, appetite regulation, and insulin sensitivity. This study offers a comprehensive review of the current research linking EDC exposure to pediatric obesity by integrating the findings from experimental and epidemiological studies. It also addresses the complexities of interpreting this evidence in the context of public health, highlighting the urgent need for further research.

Perfluorooctane sulfonate mediates GSH degradation leading to oral keratinocytes ferroptosis and mucositis through activation of the ER stress-ATF4-CHAC1 axis

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant that induces inflammatory response and oxidative stress in oral mucosa. Ferroptosis, a form of cell death characterized by iron-dependent lipid peroxidation (the oxidative degradation of lipids), was believed to play a crucial role in pathogenesis of oral mucositis; however, the involvement of PFOS-induced ferroptosis remained unclear. Our findings demonstrated that PFOS inhibited proliferation and induced pro-apoptotic effects in oral cells, with the most pronounced effects observed in human oral keratinocytes (HOK). PFOS significantly increased reactive oxygen species (ROS) and lipid peroxidation, and depleted glutathione (GSH) in HOK cells. Notably, PFOS decreased glutathione peroxidase 4 (GPX4) expression and elevated Fe2 + levels, suggesting a potential induction of ferroptosis. Ferroptosis inhibitors mitigated PFOS-induced lipid peroxidation and GSH depletion, subsequently enhancing cell viability. Mechanistically, PFOS-induced endoplasmic reticulum (ER) stress contributed to the increased expression and nuclear translocation (from the cytoplasm into the nucleus) of activating transcription factor 4 (ATF4) and up-regulated its downstream target gene Chac1. Glutathione-specific gamma-glutamylcyclotransferase 1 (CHAC1) catalyzed the conversion of GSH into cysteinylglycine and 5-oxoproline, resulting in GSH depletion-a critical factor in PFOS-induced ferroptosis. Knocking down CHAC1 attenuated PFOS-induced ferroptosis. Tauroursodeoxycholic acid (TUDCA), the classical ER stress inhibitor, attenuated PFOS-induced oral keratinocytes ferroptosis and mucositis by inhibiting ATF4/CHAC1 pathway activation. These findings elucidated the toxicological mechanisms of PFOS and proposed potential therapeutic strategies to counteract PFOS exposure induced oral mucositis.

Associations of PFAS and OH-PCBs with risk of multiple sclerosis onset and disability worsening

Exposure to per- and polyfluorinated substances (PFAS) and hydroxylated polychlorinated biphenyls (OH-PCBs) is associated with adverse human health effects, including immunosuppression. It is unknown if these substances can affect the course of autoimmune diseases. This study was based on 907 individuals with multiple sclerosis (MS) and 907 matched controls, where the MS cases were followed longitudinally using the Swedish MS register. We demonstrate sex- and disease-specific differences in serum PFAS concentrations between individuals with MS and controls. Moreover, two OH-PCBs (4-OH-CB187 and 3-OH-CB153) are associated with an increased risk of developing multiple sclerosis, regardless of sex and immigration status. With a clinical follow-up time of up to 18 years, an increase in serum concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and perfluorodecanoic acid (PFDA) decreases the risk of confirmed disability worsening in both sexes, as well as perfluoroheptanesulfonic acid (PFHpS) and perfluorononanoic acid (PFNA), only in males with MS. These results show previously unknown associations between OH-PCBs and the risk of developing MS, as well as the inverse associations between PFAS exposure and the risk of disability worsening in MS.

Evaluation of the validity of a perfluorooctane sulfonic acid exposure reconstruction using a measured serum concentration among workers with a wide range of exposure

BACKGROUND

Studies among workers with a wide range of exposure to perfluoroalkyl substances inform risk assessments. Perfluorooctane sulfonate (PFOS), a ubiquitous environmental contaminant, was recently examined in relation to mortality and cancer incidence in an occupationally exposed population by Alexander et al. in 2024. In that study, cumulative occupational exposure (mg/m3 PFOS-equivalents in air) was reconstructed using a job-exposure matrix and individual work history. While the exposure reconstruction had good face validity, an assessment of its performance in relation to serum PFOS levels would allow improved interpretation of the occupational epidemiology findings.

OBJECTIVE

The objective of this study was to assess the validity of the exposure reconstruction used by Alexander et al. (2024).

METHODS

A previous study by Olsen et al. (2003) measured serum PFOS levels in 1998 for 260 workers and because these workers were included in the epidemiologic study by Alexander et al. (2024), the study reported herein compared serum PFOS levels to those predicted using a simple compartmental pharmacokinetic model.

RESULTS

The Pearson correlation coefficient between the observed and pharmacokinetic model-predicted serum PFOS concentration was 0.80 (95% confidence interval, 0.75 to 0.84). The median ratio of predicted to observed serum concentrations was 12 (i.e. actual exposure was significantly less than predicted). The predicted serum PFOS concentrations were not sensitive to the parameters used in the pharmacokinetic model other than exposure concentration or absorption.

CONCLUSIONS

The model did not predict absolute exposure well, probably because of personal protective equipment use not being accounted for and absorption of PFOS or precursors being lower than modeled. On the other hand, the model did a reasonably good job of ranking the workers' exposure, thus classification of workers according to relative amount of cumulative PFOS-equivalents was reasonably accurate in the study by Alexander et al. (2024) when validated using the measured serum PFOS data.

Maternal concentrations of perfluoroalkyl sulfonates and alterations in white matter microstructure in the developing brains of young children

BACKGROUND

Maternal exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to child neurodevelopmental difficulties. Neuroimaging research has linked these neurodevelopmental difficulties to white matter microstructure alterations, but the effects of PFAS on children's white matter microstructure remains unclear. We investigated associations between maternal blood concentrations of six common perfluoroalkyl sulfonates and white matter alterations in young children using longitudinal neuroimaging data.

METHODS

This study included 84 maternal-child pairs from a Canadian pregnancy cohort. Maternal second trimester blood concentrations of perfluorohexanesulfonate (PFHxS) and five perfluorooctane sulfonate (PFOS) isomers were quantified. Children underwent magnetic resonance imaging scans between ages two and six (279 scans total). Adjusted linear mixed models investigated associations between each exposure and white matter fractional anisotropy (FA) and mean diffusivity (MD).

RESULTS

Higher maternal concentrations of perfluoroalkyl sulfonates were associated with higher MD and lower FA in the body and splenium of the corpus callosum of young children. Multiple sex-specific associations were found. In males, PFHxS was negatively associated with FA in the superior longitudinal fasciculus, while PFOS isomers were positively associated with MD in the inferior longitudinal fasciculus (ILF). In females, PFOS isomers were positively associated with FA in the pyramidal fibers and MD in the fornix, but negatively associated with MD in the ILF.

CONCLUSION

Maternal exposure to perfluoroalkyl sulfonates may alter sex-specific white matter development in young children, potentially contributing to neurodevelopmental difficulties. Larger studies are needed to replicate these findings and examine the neurotoxicity of these chemicals.

Association of per- and polyfluoroalkyl substances with gout risk: a cross-sectional analysis of NHANES 2007-2018 data emphasizing mixture effects

Objective

This study examined associations between serum concentrations of per- and polyfluoroalkyl substances (PFASs) and gout risk in the U.S. adult population using the National Health and Nutrition Examination Survey (NHANES) 2007-2018 data. And assessing the potential intermediary effect of uric acid.

Methods

The study included 8,494 participants, with 385 having gout. Four PFAS compounds (PFOA, PFOS, PFHxS, PFNA) were measured. PFOS is the most prevalent PFAS in the environment, biota, and human tissues. It is rapidly absorbed and accumulates in the liver, kidneys, and blood, binding to serum albumin and low-density lipoprotein. PFOA is highly persistent in the body, mainly accumulating in the kidneys and liver through enterohepatic circulation, posing risks due to its difficulty in metabolism and excretion. PFHxS has the longest metabolic half-life in humans (7.3 years) and bioaccumulates in the endocrine, immune, nervous, and reproductive systems. PFNA is the second most detected PFAS in human serum after PFOS. It is more likely to accumulate and express toxicity in the reproductive organs, liver, and immune system compared to PFOS and PFOA. Multivariate logistic regression and weighted quantile sum regression were used to assess individual and mixture effects. Mediation analysis was conducted to estimate effect of uric acid.

Results

In fully adjusted model, the associations were nonsignificant, with PFOA showing a marginally positive association. Mixture analysis revealed a significant positive association with gout risk across all models. PFOS was the largest contributor to the mixture effect. Stronger associations were observed in old people and females. Sensitivity analyses confirmed the robustness of these findings. Mediation analysis indicated significant intermediary effect of uric acid in the associations of PFAS with risk of gout, with the mediated proportion ranging from 48 to 77%.

Conclusion

This study provides evidence for a potential link between PFAS exposure and gout risk, particularly when considering mixtures. While associations with individual PFASs are largely explained by demographic and lifestyle factors, the persistent association of mixtures with gout risk highlights the importance of considering combined exposures in environmental health research. Uric acid level plays a crucial intermediary effect.

Association between plasma perfluoroalkyl substances and high-grade serous ovarian cancer overall survival: A nested case-control study

BACKGROUND

Although evidence suggests that perfluoroalkyl and polyfluoroalkyl substances (PFASs) are positively correlated to several disease risks, no studies have proven if plasma PFASs are related to ovarian cancer survival.

OBJECTIVE

To explore the association between plasma PFASs and high-grade serous ovarian cancer (HGSOC) overall survival (OS) in the population who did not smoke.

METHODS

We conducted a nested case-control study within the Ovarian Cancer Follow-Up Study, matching 159 dead patients and 159 survival ones based on body mass index, sample date, and age at diagnosis. Nine plasma PFASs were extracted by solid phase extraction and measured using a liquid chromatography system coupled with tandem mass spectrometry. Baseline plasma concentrations of perfluorinated carboxylic acids (PFCAs) [perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroheptanoic acid (PFHpA)] and perfluorinated sulfonic acids (PFSAs) [perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS)] were calculated. Odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) were calculated via conditional logistic regression models. To elucidate the combined effects, Bayesian kernel machine (BKMR), and regression quantile g-computation (QGC) models were utilized.

RESULT

In full-adjusted model, significant differences were observed between HGSOC survival and perfluorobutane sulfonic acid, PFHpA, PFHxS, PFOS, PFCA, and PFSA. ORs and 95 %CIs were 2.74 (1.41-5.31), 1.97 (1.03-3.76), 2.13 (1.15-3.95), 2.28 (1.16-4.47), 3.74 (1.78-7.85), and 2.56 (1.31-5.01), respectively for the highest tertile compared with the lowest tertile. The QGC and BKMR models indicated that elevated concentrations of PFAS mixtures were associated with poor OS in HGSOC.

CONCLUSIONS

Both individual and mixed plasma PFASs may relate to poor OS of HGSOC. Further research is necessary to establish causality, and it is recommended to reinforce environmental risk mitigation strategies to minimize PFAS exposure.

Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) from contaminated water and risk of childhood cancer in California, 2000-2015

Background

Few studies have investigated associations between per- and polyfluoroalkyl substances (PFAS) and childhood cancers. Detectable levels of PFAS in California water districts were reported in the Third Unregulated Contaminant Monitoring Rule for 2013-2015.

Methods

Geocoded residences at birth were linked to corresponding water district boundaries for 10,220 California-born children (aged 0-15 years) diagnosed with cancers (2000-2015) and 29,974 healthy controls. A pharmacokinetic model was used to predict average steady-state maternal serum concentrations of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) from contaminated drinking water. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) per doubling of background exposure were calculated for cancers with at least 90 cases.

Results

Predicted PFOS and PFOA maternal serum concentrations ranged from background (5 ng/ml PFOS and 2 ng/ml PFOA) to 22.89 ng/ml and 6.66 ng/ml, respectively. There were suggestive associations between PFOS and nonastrocytoma gliomas (n = 268; AOR = 1.26; 95% CI: 0.99, 1.60), acute myeloid leukemia (n = 500; AOR = 1.14; 95% CI: 0.94, 1.39), Wilms tumors (n = 556, AOR = 1.15; 95% CI: 0.96, 1.38), and noncentral system embryonal tumors (n = 2,880; AOR = 1.07; 95% CI: 0.98, 1.17), and between PFOA and non-Hodgkin lymphoma (n = 384; AOR = 1.19; 95% CI: 0.95, 1.49). Among children of Mexico-born mothers, there was increased risk of Wilms tumor (n = 101; AORPFOS = 1.52; 95% CI: 1.06, 2.18; AORPFOA = 1.59, 95% CI: 1.12, 2.24) and noncentral system embryonal tumors (n = 557; AORPFOS = 1.24, 95% CI: 1.03, 1.50; AORPFOA = 1.19, 95% CI: 0.98, 1.45).

Conclusion

Results suggest associations between predicted prenatal maternal PFAS serum concentrations and some childhood cancers. Future analyses are warranted.

Assessing PFAS in drinking water: Insights from the Czech Republic's risk-based monitoring approach

This study investigates the presence of perfluoroalkyl substances (PFAS) in the drinking water supplies in the Czech Republic using a risk-based monitoring approach. Tap water samples (n = 27) from sources close to areas potentially contaminated with PFAS were analysed. A total of 28 PFAS were measured using ultra-performance liquid chromatography with tandem mass spectrometry after solid phase extraction. Total PFAS concentrations (∑PFAS) varied from undetectable to 90.8 ng/L, with perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA) and perfluorobutane sulfonic acid (PFBS) being the most abundant, detected in over 70% of samples. Risk-based monitoring in drinking water showed that commercial wells had higher PFAS levels compared to tap water, particularly C4-C9 perfluorocarboxylic acids (PFCAs), possibly due to proximity to industrial areas. However, the hypothesis that risk-based monitoring is more effective than random monitoring was not confirmed, possibly because specific sources did not produce the target PFAS or because of the wide range and less obvious sources of potential contamination. The study also assessed exposure risks and compliance with regulatory thresholds. Weekly intake estimates for adults and children indicated that regular consumption of most contaminated water sample would exceed the tolerable weekly intake. Compared to EU regulations, none of the tap water samples exceeded the 'Sum of PFAS' parametric value of 100 ng/L, though one sample approached this limit. In addition, surface water samples from the Jizera River (n = 21) showed a wider range of PFAS, with C7-C10 PFCAs, PFBS, and perfluorooctane sulfonic acid (PFOS) in every sample, with higher PFOS concentrations at a median of 2.56 ng/L. ∑PFAS concentrations increased downstream, rising from 1.08 ng/L near the spring to 26 ng/L downstream. This comprehensive analysis highlights the need for detailed/areal monitoring to also address hidden or non-obvious sources of PFAS contamination.

Perfluorooctane sulfonate causes HK-2 cell injury through ferroptosis and endoplasmic reticulum stress pathways

Perfluorooctane sulfonate (PFOS) is a synthetic persistent organic compound that is widely used in industrial products. Studies have shown that PFOS can accumulate in environment and pose a threat to human health. As the kidney is the main excretory organ for PFOS, it is important to study PFOS damage to the kidney to investigate its toxicity. Human proximal tubular epithelial cells (HK-2) were treated with 200 μM PFOS or 1 μM Fer-1. Cell viability, the levels of MDA, GSH, intracellular iron ion, and GPX-4 were determined. The expression of KIM-1 and endoplasmic reticulum stress (ERS) related proteins were determined. The expression levels of KIM-1, a marker of renal tubular injury, and ERS-related proteins, GRP78, ATF6, IRE1, and PERK, were significantly increased in HK-2 cells exposed to PFOS. The levels of MDA and intracellular total iron ion also were significantly increased in HK-2 cells exposed to PFOS and the levels of GSH and GPX-4 were significantly decreased. PFOS can damage HK-2 cells through ferroptosis and endoplasmic reticulum stress, which provides a theoretical foundation for exploring the toxicity of PFOS to the kidney.

Protective Effects of Resveratrol Against Perfluorooctanoic Acid-Induced Testicular and Epididymal Toxicity in Adult Rats Exposed During Their Prepubertal Period

The antioxidant properties of resveratrol (RES) against oxidative toxicity induced by testicular toxicants are well documented. The current study aimed to investigate the probable beneficial role of RES on male reproduction in adult rats following prepubertal exposure to perfluorooctanoic acid (PFOA). Healthy rats of the Wistar strain (23 days old) were allocated into four groups. Rats in group I did not receive any treatment, while rats in groups II, III, and IV received RES, PFOA, and RES + PFOA, respectively, between days 23 and 56 and were monitored for up to 90 days. Exposure to PFOA resulted in a significant reduction in spermiogram parameters, testicular 3β- and 17β-HSD activity levels, and circulatory levels of testosterone. A significant elevation in LPx, PCs, H2O2, and O2-, associated with a concomitant reduction in SOD, CAT, GPx, GR, and GSH, was noticed in the testes, as well as region-specific changes in pro- and antioxidants in the epididymides of exposed rats compared to controls. A significant increase in serum FSH and LH, testicular cholesterol levels, and caspase-3 activity was observed in PFOA-exposed rats compared to controls. Histological analysis revealed that the integrity of the testes was deteriorated in PFOA-exposed rats. Transcriptomic profiling of the testes and epididymides revealed 98 and 611 altered genes, respectively. In the testes, apoptosis and glutathione pathways were disrupted, while in the epididymides, glutathione and bile secretion pathways were altered in PFOA-exposed rats. PFOA exposure resulted in the down-regulation in the testes of 17β-HSD, StAR, nfe2l2, ar, Lhcgr, and mRNA levels, associated with the up-regulation of casp3 mRNA, and down-regulation of alpha 1 adrenoceptor, muscarinic choline receptor 3, and androgen receptor in the epididymides of exposed rats compared to the controls. These events might lead to male infertility in PFOA-exposed rats. In contrast, restoration of selected reproductive variables was observed in RES plus PFOA-exposed rats compared to rats exposed to PFOA alone. Taken together, we postulate that prepubertal exposure to PFOA triggered oxidative damage and altered genes in the testes and epididymides, leading to suppressed male reproductive health in adult rats, while RES, with its steroidogenic, antiapoptotic, and antioxidant effects, restored PFOA-induced fertility potential in rats.

Association Kinetics for Perfluorinated n-Alkyl Radicals

Radical-radical reaction channels are important in the pyrolysis and oxidation chemistry of perfluoroalkyl substances (PFAS). In particular, unimolecular dissociation reactions within unbranched n-perfluoroalkyl chains, and their corresponding reverse barrierless association reactions, are expected to be significant contributors to the gas-phase thermal decomposition of families of species such as perfluorinated carboxylic acids and perfluorinated sulfonic acids. Unfortunately, experimental data for these reactions are scarce and uncertain. Furthermore, obtaining reliable theoretical predictions for such reactions is a laborious and computationally intensive task. In this work, the chemical kinetics of the various association/decomposition reactions producing/decomposing the C2-C4 series of unbranched n-perfluoroalkanes (C2F6, C3F8, and C4F10) are examined using state-of-the-art ab initio transition-state-theory-based master-equation calculations. The variable-reaction-coordinate transition-state theory (VRC-TST) formalism is employed in computing the microcanonical and canonical rates for the association reactions. Reaction thermochemistry is obtained via composite quantum chemistry calculations and the laddering of error-canceling reaction schemes via a connectivity-based hierarchy approach employing ANL1/ANL0-style reference energies. Lennard-Jones collision model parameters for the considered systems were estimated by a direct dynamics approach, and collisional energy transfer parameters were obtained from analogies to systems of similar size and heavy-atom connectivity. A one-dimensional master equation approach was used to convert the microcanonical rate coefficients from the VRC-TST analysis into temperature- and pressure-dependent rate constants for the association reactions and the reverse dissociation reactions. The data are reported in standardized formats for usage in comprehensive chemical kinetic models for PFAS thermal destruction.

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.

Perfluorohexanesulfonic Acid (PFHxS) Induces Hepatotoxicity through the PPAR Signaling Pathway in Larval Zebrafish (Danio rerio)

In recent years, the industrial substitution of long-chain per- and polyfluoroalkyl substances (PFAS) with short-chain alternatives has become increasingly prevalent, resulting in the widespread environmental detection of perfluorohexanesulfonic acid (PFHxS), a short-chain PFAS. However, there remains limited information about the potential adverse effects of PFHxS at environmental concentrations to wildlife. Here, early life stage zebrafish (Danio rerio) were exposed to environmentally relevant concentrations of PFHxS to better characterize the adverse effects of PFHxS on aquatic organisms. Nontargeted, transcriptomic analysis revealed potential hepatotoxic effects in exposed larvae, including macrovesicular and microvesicular hepatic steatosis, as well as focal liver necrosis. Morphological, histological, biochemical, and targeted transcript expression profiles further confirmed significant alterations in hepatocellular lesion numbers, liver pathological structures, relative liver size, liver biochemical parameters, and liver function genes. To validate the PPAR-mediated toxicological mechanism identified as an enriched pathway through in silico bioinformatics analysis, we tested the coexposure to an antagonist and PPAR morpholino knockdown. This intervention alleviated PFHxS-induced hepatic effects, including reductions in the levels of aspartate aminotransferase, alanine aminotransferase, total cholesterol, and total triglycerides. Our results demonstrate that environmentally relevant concentrations of PFHxS can impair liver development and function in fish, which could have potential risks to aquatic organisms.

Per- And Poly-Fluoroalkyl Substances (PFAS) Exposure and Risk of Breast, and Female Genital Cancers: A Systematic Review and Meta-Analysis

BACKGROUND

PFASs, synthetic chemicals, can be encountered by humans through occupational or environmental exposure, and some reports suggest that they can disrupt endocrine and hormonal activities. In this comprehensive review and meta-analysis, we explored the connection between exposure to PFASs and the risks of breast and female genital cancers.

METHODS

We systematically reviewed the literature from IARC Monographs, ATSDR documents, and PubMed (as of January 2024) for cohort, case-control, and ecological studies on PFAS exposure and breast or female genital cancers. Four reviewers independently screened studies, and data extraction included study design, patient characteristics, and effect size measures. The quality of studies was assessed using the modified version of the Newcastle-Ottawa Scale (NOS). Forest plots of relative risks (RR) were constructed for breast and female genital cancer. Meta-analyses were conducted using random-effects models, stratified analyses, dose-response assessments, and publication bias evaluation.

RESULTS

The meta-analysis included 24 studies, comprising 10 cohort, 13 case-control, and one ecological study. The summary relative risk (RR) of breast cancer for PFOA exposure was 1.08 (95% CI = 0.97-1.20; n=21), and for PFOS was 1.00 (95% CI = 0.85-1.18; n=12). The RR for ovarian cancer and PFAS was 1.07 (95% CI = 1.04-1.09; n=12). The stratification by quality score, year of publication, and exposure source did not reveal any differences. However, analysis by geographical region (p=0.01) and study design (p=0.03) did show differences, particularly in terms of incidence. Stratified analyses of the dose-response relationship did not reveal a trend in the risk of breast cancer or female genital cancers, and no publication bias was found for either cancer type. No results were available for cervical and endometrial cancers.

CONCLUSION

In summary, we have found an association between PFAS exposure and ovarian cancer and a possible effect on breast cancer incidence in some specific groups. Although potential bias and confounding prevent conclusions regarding causality, these findings may hold significance for females who encounter such pollutants in their occupational or daily environments.

Early pregnancy serum PFAS are associated with alterations in the maternal lipidome

Per- and polyfluoroalkyl substances (PFAS) have been detected in the blood of humans and animals worldwide. Exposure to some PFAS are associated with multiple adverse pregnancy outcomes. Existing literature has identified a strong association with PFAS exposure and metabolic dysfunction in humans, including modification of lipid metabolism. Using a subset of the Michigan Mother-Infant Pairs cohort (n = 95), this study investigated associations between first trimester plasma levels of PFAS and maternal lipids and metabolites in the first trimester (T1), at the time of delivery (T3), and in the infant cord blood (CB) using untargeted shotgun lipidomics and metabolomics. Identifying PFAS-induced alterations in the maternal lipid- or metabolome at specific timepoints may help elucidate windows of susceptibility to adverse pregnancy outcomes. Out of 9 PFAS measured, 7 were detected in at least 20% of samples and were used for further analyses. PFOS and PFHxS were measured at the highest concentrations with medians of 5.76 ng/mL and 3.33 ng/mL, respectively. PFOA, PFNA, and PFDA had lower measured values with medians of <1.2 ng/mL. PFHxS concentrations were positively associated with monounsaturated sphingomyelins (SMs) in T1 maternal plasma in adjusted models, determined by an adjusted p-value (q) < 0.1. PFHxS was positively associated with saturated and polyunsaturated SMs and inversely associated with saturated diacylglycerols in T1. Following metabolite-specific analysis, two mono-unsaturated diacylglycerols with carbon chain lengths of 32 and 35 were inversely associated with PFHxS in T1. In T3, only the association between PFHxS and SMs remained, but was attenuated. In addition, PFDA was associated with an increase in polyunsaturated plasmenyl-phosphatidylethanolamines in T3. No associations were identified between PFAS and infant cord blood lipids. Continued research into PFAS associated disruptions in lipid metabolism at sensitive stages of gestation may provide insight into the mechanisms that lead to adverse birth and pregnancy outcomes.

Occurrence, Fate, and Removal of Per- and Polyfluoroalkyl Substances (PFAS) in Small- and Large-Scale Municipal Wastewater Treatment Facilities in the United States

Wastewater treatment plants (WWTPs) could be conduits of polyfluoroalkyl substances (PFAS) contaminants in the environment. This study investigated the fate of 40 PFAS compounds across nine municipal WWTPs with varying treatment capacity and processes. High concentrations of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) were detected in wastewater, with the ratio of their total concentrations (∑PFCAs/∑PFSAs) always greater than one. Transformation of precursors by activated sludge processes significantly increased the concentrations of short-chain PFCAs (e.g., perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA)), while further advanced treatment processes offered minimal removal of perfluoroalkyl acids. Treatment capacity and PFAS removal efficiency showed no apparent correlation. The maximum possible PFAS loads discharged from WWTPs were 340-9645 g·year-1, similar to those entering the WWTPs. Among six regulated PFAS compounds, detection frequency was 100% for five (perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorobutanesulfonic acid (PFBS), and perfluorohexanesulfonic acid (PFHxS)) and 67% for hexafluoropropylene oxide dimer acid (HFPO-DA) (Gen-X). Concentrations of PFOA and PFOS in WWTP discharges consistently exceeded 4 ng·L-1. The hazard index (HI) for mixtures containing two or more of the four PFAS (PFNA, PFBS, PFHxS, and HFPO-DA) ranged from 0.2 to 6.1. These findings indicate that wastewater discharges may pose a risk, emphasizing the need for enhanced PFAS removal strategies in wastewater treatment processes.

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 exposure and risk of gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Per- and poly-fluoroalkyl substances (PFASs) are a group of synthetic chemicals used since the 1940s in industrial and consumer applications. These substances are known or suspected to cause cancer, particularly kidney and testicular cancer. However, their association with other types of cancer is not well understood. This review aims to investigate the link between PFAS exposure and the risks of other cancers, including gastrointestinal cancers such as esophageal, gastric, colorectal, and pancreatic cancer.

METHODS

We conducted a systematic review of literature from the International Agency for Research on Cancer Monographs, Agency for Toxic Substances and Disease Registry documents, and PubMed (up to January 2024) focusing on the association between PFAS exposure and gastrointestinal cancers. Four independent reviewers screened the studies, extracted the information, and evaluated the quality of the studies using a modified Newcastle-Ottawa Scale. Meta-analyses were performed with random-effects models, including stratified analyses and dose-response assessments.

RESULTS

The meta-analysis included 17 studies. The summary relative risks (RR) of esophageal cancer for perfluorooctanoic acid (PFOA) exposure was 0.75 (95% confidence interval [CI], 0.35-1.60; n = 2), and for perfluorooctane sulfonic acid (PFOS) was 1.76 (95% CI, 0.32-9.68; n = 1). The RR for gastric cancer and PFOA was 0.59 (95% CI, 0.28-1.21; n = 2) and PFAS was 0.96 (95% CI, 0.83-1.12; n = 2). The RR for colorectal cancer and PFOA was 0.83 (95% CI, 0.65-1.06; n = 6) and PFOS was 0.71 (95% CI, 0.22-2.27; n = 4). The RR for pancreatic cancer was 1.02 (95% CI, 0.90-1.15; n = 9) and PFOS was 0.92 (95% CI, 0.76-1.11; n = 2). Stratified analyses by geographical region, study design, quality score, year of publication, gender, and outcome revealed no associations for colorectal and pancreatic cancers. No dose-response trends were identified. Publication bias was suggested for gastric cancer.

CONCLUSION

Our study suggested no association between PFAS exposure and esophageal, gastric, colorectal, or pancreatic cancer. More rigorous research is needed to investigate this relationship in different settings, with precise PFAS quantification, a wider range of compounds, larger sample sizes for specific cancers, and better control for potential confounders. Our meta-analysis suggests inconclusive evidence, highlighting the need for further research.

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).

Perfluoroalkyl substances exposure and the risk of breast cancer: A nested case-control study in Jinchang Cohort

BACKGROUND

As persistent organic pollutants (POPs), perfluoroalkyl substances (PFAS) may potentially impact human health. Our study aimed to investigate the prospective association between PFAS exposure and the incidence risk of breast cancer in females.

METHODS

By fully following the Jinchang Cohort after a decade, we conducted this nested case-control study with 135 incidence cases of breast cancer (BC) and 540 bias-paired controls. The PFAS levels were tested by baseline serum samples. Conditional logistic regression and a restricted cubic spline model were employed to investigate the BC incidence risks and the dose-response associated with single PFAS component exposure. Furthermore, the Quantile g-computation model (Qgc), random forest model (RFM), and bayesian kernel machine regression models (BKMR) were integrated to estimate the mixed effects of PFAS exposure on the incidence risk of BC.

RESULTS

Exposures to specific PFAS components were positively associated with an increased incidence risk of breast cancer. By grouping the study population into different baseline menopausal statuses, PFHxS, PFNA, PFBA, PFUdA, PFOS, and PFDA demonstrated a similarly positive correlation with BC incidence risks. However, the increased incidence risks of BC associated with PFOA, PFOS, PFUdA, and 9CL-PF3ONS exposure were exclusively found in the premenopausal population. Both BKMR and Qgc revealed that exposure to mixed PFAS was associated with an increased risk of breast cancer, with Qgc specifically indicating an odds ratio (OR) of 2.21 (95% CI: 1.53, 3.19). Random forests showed that PFBA, PFOS, PFHxS, and PFDA emerged as predominant factors potentially influencing breast cancer incidence.

CONCLUSION

Our findings suggest a strong association between PFAS exposure and the incidence of breast cancer. Premenopausal women should exercise more caution regarding PFAS exposure.

Per- and polyfluoroalkyl substances (PFAS) and hypertensive disorders of Pregnancy- integration of epidemiological and mechanistic evidence

BACKGROUND

Hypertensive disorders of pregnancy (HDP) remain a significant global health burden despite medical advancements. HDP prevalence appears to be rising, leading to increased maternal and fetal complications, mortality, and substantial healthcare costs. The etiology of HDP are complex and multifaceted, influenced by factors like nutrition, obesity, stress, metabolic disorders, and genetics. Emerging evidence suggests environmental pollutants, particularly Per- and polyfluoroalkyl substances (PFAS), may contribute to HDP development.

OBJECTIVE

This review integrates epidemiological and mechanistic data to explore the intricate relationship between PFAS exposure and HDP.

EPIDEMIOLOGICAL EVIDENCE

Studies show varying degrees of association between PFAS exposure and HDP, with some demonstrating positive correlations, particularly with preeclampsia. Meta-analyses suggest potential fetal sex-specific differences in these associations.

MECHANISTIC INSIGHTS

Mechanistically, PFAS exposure appears to disrupt vascular hemodynamics, placental development, and critical processes like angiogenesis and sex steroid regulation. Experimental studies reveal alterations in the renin-angiotensin system, trophoblast invasion, oxidative stress, inflammation, and hormonal dysregulation - all of which contribute to HDP pathogenesis. Elucidating these mechanisms is crucial for developing preventive strategies.

THERAPEUTIC POTENTIAL

Targeted interventions such as AT2R agonists, caspase inhibitors, and modulation of specific microRNAs show promise in mitigating adverse outcomes associated with PFAS exposure during pregnancy.

KNOWLEDGE GAPS AND FUTURE DIRECTIONS

Further research is needed to comprehensively understand the full spectrum of PFAS-induced placental alterations and their long-term implications for maternal and fetal health. This knowledge will be instrumental in developing effective preventive and therapeutic strategies for HDP in a changing environmental landscape.

E-waste in the environment: Unveiling the sources, carcinogenic links, and sustainable management strategies

E-waste refers to the electrical and electronic equipment discarded without the intent of reuse or at the end of its functional lifespan. In 2022, approximately 62 billion kg of e-waste, equivalent to 7.8 kg per capita, was generated globally. With an alarming annual growth of approximately 2 million metric tonnes, e-waste production may exceed 82 billion kg by 2030. Improper disposal of e-waste can be detrimental to human health and the entire biosphere. E-waste encompasses a wide range of materials, including heavy metals, Polychlorinated Biphenyls (PCBs), Per- and Polyfluoroalkyl Substances (PFAS), Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated Dibenzo-dioxins and -furans (PCDD/Fs), Polybrominated Diphenyl Ethers (PBDEs), and radioactive elements. E-waste, when disposed inappropriately can directly contaminate the aquatic and terrestrial environment, leading to human exposure through ingestion, inhalation, dermal absorption, and trans-placental transfer. These detrimental contaminants can directly enter the human body from the environment and may fuel carcinogenesis by modulating cell cycle proteins, redox homeostasis, and mutations. Heavy metals such as cadmium, mercury, arsenic, lead, chromium, and nickel, along with organic pollutants like PAHs, PCBs, PBDEs, PFAS, and radioactive elements, play a crucial role in inducing malignancy. Effective collection, sorting, proper recycling, and appropriate disposal techniques are essential to reduce environmental contamination with e-waste-derived chemicals. Hence, this comprehensive review aims to unravel the global environmental burden of e-waste and its links to carcinogenesis in humans. Furthermore, it provides an inclusive discussion on potential treatment approaches to minimize environmental e-waste contamination.

Associations between per- and poly-fluoroalkyl substance (PFAS) exposure and immune responses among women in the California Teachers study: A cross-sectional evaluation

INTRODUCTION

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that have been linked to a number of health outcomes, including those related to immune dysfunction. However, there are limited numbers of epidemiological-based studies that directly examine the association between PFAS exposure and immune responses.

METHODS

In this cross-sectional study nested in the California Teachers Study cohort, we measured nine PFAS analytes in serum. Of the 9 analytes, we further evaluated four (PFHxS [perfluorohexane sulfonate], PFNA [perfluorononanoic acid], PFOA [perfluorooctanoic acid], PFOS [perfluorooctanesulfonic acid]) that had detection levels of > 80 %, in relation to 16 systemic inflammatory/immune markers and corresponding immune pathways (Th1 [pro-inflammatory/macrophage activation], B-cell activation, and T-cell activation). Study participants (n = 722) were female, completed a questionnaire regarding various health measures and behaviors, and donated a blood sample between 2013-2016. The association between PFAS analytes and individual immune markers and pathways were evaluated by calculating odds ratios (OR) and 95 % confidence intervals (CI) in a logistic regression model. PFAS analytes were evaluated both as a dichotomous exposure (above or below the respective median) and as a continuous variable (per 1 unit increase [ng/mL]).

RESULTS

The prevalence of detecting any PFAS analyte rose with increasing age, with the highest PFAS prevalence observed among those aged 75 + years and the lowest PFAS prevalence observed among those aged 40-49 years (study participant age range: 40-95 years). Significant associations with BAFF (B-cell activating factor) levels above the median were observed among participants with elevated (defined as above the median) levels of PFHxS (OR=1.53), PFOA (OR=1.43), and PFOS (OR=1.40). Similarly, there were statistically significant associations between elevated levels of PFHxS and TNFRII (tumor necrosis factor receptor 2) levels (OR=1.78) and IL2Rα (interleukin 2 receptor subunit alpha) levels (OR=1.48). We also observed significant inverse associations between elevated PFNA and sCD14 (soluble cluster of differentiation 14) (OR=0.73). No significant associations were observed between elevated PFNA and any immune marker. Evaluation of PFAS exposures as continuous exposures in association with dichotomized cytokines were generally consistent with the dichotomized associations.

CONCLUSIONS

PFAS exposure was associated with altered levels of circulating inflammatory/immune markers; the associations were specific to PFAS analyte and immune marker. If validated, our results may suggest potential immune mechanisms underlying associations between the different PFAS analytes and adverse health outcomes.

Fate of per- and polyfluoroalkyl substances at a 40-year dedicated municipal biosolids land disposal site

The fate of per- and polyfluoroalkyl substances (PFAS) was evaluated at a site where municipal biosolids have been applied annually for 38 years as a waste management strategy. Soil cores (1.8 m in 30-cm sections), groundwater from four wells, and biosolids applied in 2022 were analyzed for PFAS (54 targeted, 17 semi-quantified) using liquid chromatography high resolution mass spectrometry including suspect screening. Total PFAS concentrations decreased with soil depth from 1700 ng/g to 2.06 ng/g. PFAS distribution in 2022 biosolids were 60 mol% perfluoroalkyl acid (PFAA) precursors and intermediates. The surface soil was dominated by long-chain PFAAs (67-76 mol%) reflecting precursor degradation after biosolids application. Presence of semi-quantified intermediates further reflects precursor degradation in surface soil. Long-chain PFAAs diminished with depth while short-chain PFAAs increased with up to 98 and 96 mol% short-chain PFAAs in the bottom depth and groundwater, respectively. PFAS distribution with depth is consistent with chain-length dependent sorption-impacted transport and the high organic carbon content of the surface soil (15.2 % OC) which subsequently decreased with depth (~2-3 % OC at >60 cm). High organic carbon content in the upper horizon is likely from decades of high biosolids application rates, which contributed to minimizing leaching of long-chain PFAS. While the well within the dedicated land disposal is not drinking water, for comparison only, PFAS concentrations in this well only marginally exceeded the EU drinking water directive for total PFAS and a few individual short-chain PFAS, but did exceed tenfold, the USEPA drinking water standard for PFOA.

Association between exposure to per- and polyfluoroalkyl substances and missed miscarriage: A hospital-based case-control study in Shanghai, China

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants linked to reproductive disruptions. This study investigated the relationship between PFAS exposure and missed miscarriage in a hospital-based, case-control study in Shanghai, China. There were 393 women in our research, including 198 cases and 195 controls. Concentrations of 30 PFAS in plasma were quantified using HPLC-MS/MS, and 15 PFAS were detected at a rate greater than 90 percent. PFOA, L-PFOS, and PFOS isomers were significantly higher in the cases than those in the controls. 13 PFAS showed significant positive associations with miscarriage risk after adjustment for confounders, particularly PFOA (OR: 2.99, 95 % CI: 1.96-4.68) and various PFOS isomers. BKMR analysis confirmed higher overall PFAS levels were associated with increased miscarriage risk. These findings highlight the potential reproductive toxicity of PFAS and underscore the need for further investigations and regulatory actions to mitigate PFAS exposure in pregnant women.

Advancing PFAS risk assessment: Integrative approaches using agent-based modelling and physiologically-based kinetic for environmental and health safety

Per- and polyfluoroalkyl substances (PFAS), ubiquitous in a myriad of consumer and industrial products, and depending on the doses of exposure represent a hazard to both environmental and public health, owing to their persistent, mobile, and bio accumulative properties. These substances exhibit long half-lives in humans and can induce potential immunotoxic effects at low exposure levels, sparking growing concerns. While the European Food Safety Authority (EFSA) has assessed the risk to human health related to the presence of PFAS in food, in which a reduced antibody response to vaccination in infants was considered as the most critical human health effect, a comprehensive grasp of the molecular mechanisms spearheading PFAS-induced immunotoxicity is yet to be attained. Leveraging modern computational tools, including the Agent-Based Model (ABM) Universal Immune System Simulator (UISS) and Physiologically Based Kinetic (PBK) models, a deeper insight into the complex mechanisms of PFAS was sought. The adapted UISS serves as a vital tool in chemical risk assessments, simulating the host immune system's reactions to diverse stimuli and monitoring biological entities within specific adverse health contexts. In tandem, PBK models unravelling PFAS' biokinetics within the body i.e. absorption, distribution, metabolism, and elimination, facilitating the development of time-concentration profiles from birth to 75 years at varied dosage levels, thereby enhancing UISS-TOX's predictive abilities. The integrated use of these computational frameworks shows promises in leveraging new scientific evidence to support risk assessments of PFAS. This innovative approach not only allowed to bridge existing data gaps but also unveiled complex mechanisms and the identification of unanticipated dynamics, potentially guiding more informed risk assessments, regulatory decisions, and associated risk mitigations measures for the future.

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.

A portable fluorescence sensing system for timely onsite perfluorooctane sulfonate detection based on an aggregate induced emission fluorescence sensor

Perfluorooctane sulfonate (PFOS), a ubiquitous persistent organic pollutant, has aroused growing concern due to its adverse effects on human health. Timely onsite monitoring of PFOS in heavily contaminated areas is crucial for effective pollution management and prevention of its spread. However, relevant PFOS detection methods have rarely been reported. Herein, we developed a fluorescence sensing system capable of achieving timely onsite detection of PFOS under outdoor conditions. First, aggregate induced emission (AIE) fluorescence sensors, TPE-PAs, were synthesized. The optimized sensor could selectively interact with PFOS through electrostatic attraction and hydrogen bonding and exhibited prominent fluorescence enhancement after treating with PFOS. There was a good linear relationship between the fluorescence enhancement and PFOS concentration in the range of 0.05-30 ppm, and the limit of detection was measured to be 0.047 ppm. In addition, owing to the AIE fluorescence mechanism and high concentration of TPE-PAs in the sensing medium, the sensor demonstrated excellent anti-interference performance. Second, we developed a portable fluorometer, by modifying the power supply and sample cell of a tiny fluorometer, and further integrated this modified fluorometer, the prepared fluorescence sensor, standard PFOS solutions and other consumables into a portable test system. This test system showed good detection accuracy and reliability and successfully achieved timely onsite PFOS detection in real water samples.

Metabolic changes associated with PFAS exposure in firefighters: A pilot study

This pilot study investigated the association between occupational exposure to per- and polyfluoroalkyl substances (PFASs) and metabolic profiles among two groups of aviation firefighters (n = 37), with an average of 6 and 31 years of working experience (here referred as junior and senior firefighters) at airports across Australia, with samples collected in 2013. PFAS levels in serum were determined in a previous study to be >17 times higher in the senior firefighter group, reflecting the difference in their occupational exposure to fluorosurfactants among the groups. The aim was to examine metabolic patterns across a broad range of PFAS exposure by comparing metabolic differences and their associations with PFAS levels. In this cross-sectional study, the length of firefighting experience and PFAS levels in serum were both further associated with changes in several classes of metabolites, including free fatty acids, bile acids, amino acids, lipids and metabolites related to gut microbial metabolism. The metabolites associated with the length of firefighting experience showed similarities with the metabolites associated with PFAS levels. A non-monotonic response to PFAS concentrations, particularly in saturated fatty acids, was also observed. In the junior firefighter group, the PFAS concentrations were positively associated with saturated fatty acids, i.e., the saturated fatty acid levels increased with increased PFAS levels. In the senior firefighter group, the trend was opposite, with saturated fatty acids decreasing with increasing levels of PFAS. Accounting for potential confounding factors such as BMI and age could not explain the results. While the study population was small, our results plausibly indicate that PFAS exposure can lead to a metabolic compensation strategy that is disrupted at high, long-term exposures. Our study also suggests that serum metabolites serve as better effect-based markers of the impact of exposure than the traditional clinical measurements alone, such as total triglycerides or total cholesterol.