Health-related toxicity of emerging per- and polyfluoroalkyl substances: Comparison to legacy PFOS and PFOA

Associations of perfluoroalkyl substances with metabolic-associated fatty liver disease and non-alcoholic fatty liver disease: NHANES 2017-2018

OBJECTIVES

This study investigated the potential effects of perfluoroalkyl substance (PFAS) in serum on MAFLD, NAFLD, and liver fibrosis.

METHODS

Our sample included 696 participants (≥ 18 years) from the 2017-2018 NHANES study with available serum PFASs, covariates, and outcomes. Using the first quartile of PFAS as the reference group, we used weighted binary logistic regression and multiple ordered logistic regression used to analyze the relationship between PFAS and MAFLD, NAFLD, and liver fibrosis and multiple ordinal logistic regression to investigate the relationship between PFAS and MAFLD, NAFLD, and liver fibrosis and calculated the odds ratio (OR) and 95% confidence interval for each chemical. Finally, stratified analysis and sensitivity analysis were performed according to gender, age, BMI, and serum cotinine concentration.

RESULTS

A total of 696 study subjects were included, including 212 NAFLD patients (weighted 27.03%) and 253 MAFLD patients (weighted 32.65%). The quartile 2 of serum PFOA was positively correlated with MAFLD and NAFLD (MAFLD, OR 2.29, 95% CI 1.05-4.98; NAFLD, OR 2.37, 95% CI 1.03-5.47). PFAS were not significantly associated with liver fibrosis after adjusting for potential confounders in MAFLD and NAFLD. Stratified analysis showed that PFOA was strongly associated with MAFLD, NAFLD, and liver fibrosis in males and obese subjects. In women over 60 years old, PFHxS was also correlated with MAFLD, NAFLD, and liver fibrosis.

CONCLUSION

The serum PFOA was positively associated with MAFLD and NAFLD in US adults. After stratified analysis, the serum PFHxS was correlated with MFALD, NAFLD, and liver fibrosis.

How Per- and Poly-Fluoroalkyl Substances Affect Gamete Viability and Fertilization Capability: Insights from the Literature

There has been emerging research linking per- and poly-fluoroalkyl substances (PFAS) to gamete viability and fertility. PFAS, prevalent in the environment and water supplies, undergo slow degradation due to their C-F bond and a long half-life (2.3-8.5 years). In females, PFAS inhibit the hypothalamic-pituitary-gonadal (HPG) axis, reducing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels, leading to the inhibition of androgen and estradiol production. PFAS have been found to cause detrimental effects on egg quality through impairing folliculogenesis. In males, PFAS can impair sperm motility and morphology: two fundamental qualities of successful fertilization. PFAS exposure has been proven to inhibit testosterone production, sperm capacitation, and acrosomal reaction. After fertilization, the results of PFAS exposure to embryos have also been investigated, showing reduced development to the blastocyst stage. The aim of this review is to report the main findings in the literature on the impact of PFAS exposure to gamete competency and fertilization capability by highlighting key studies on both male and female fertility. We report that there is significant evidence demonstrating the negative impacts on fertility after PFAS exposure. At high doses, these environmentally abundant and widespread compounds can significantly affect human fertility.

Modulating the ion-transfer electrochemistry of perfluorooctanoate with serum albumin and β-cyclodextrin

Per- and polyfluoroalkyl substances (PFAS) are durable synthetic pollutants that persist in the environment and resist biodegradation. Ion-transfer electrochemistry at aqueous-organic interfaces is a simple strategy for the detection of ionised PFAS. Herein, we investigate the modulation of the ion transfer voltammetry of perfluorooctanoate (PFOA) at liquid-liquid micro-interface arrays by aqueous phase bovine serum albumin (BSA) or β-cyclodextrin (β-CD) and examine the determination of association constants for these binding interactions. By tracking the ion transfer current due to ionised, uncomplexed PFOA as a function of BSA or β-CD concentration, titration curves are produced. Fitting of a binding isotherm to these data provides the association constants. The association constant of PFOA with the BSA determined in this way was ca. 105 M-1 assuming a 1 : 1 binding. Likewise, the association constant for PFOA with β-CD was ca. 104 M-1 for a 1 : 1 β-CD-PFOA complex. Finally, the simultaneous effect of both BSA and β-CD on the ion transfer voltammetry of PFOA was studied, showing clearly that PFOA bound to BSA is released (de-complexed) upon addition of β-CD. The results presented here show ion transfer voltammetry as a simple strategy for the study of molecular and biomolecular binding of ionised PFAS and is potentially useful in understanding the affinity of different PFAS with aqueous phase binding agents such as proteins and carbohydrates.

Association of Combined PFOA, PFOS, Metals and Allostatic Load on Hepatic Disease Risk

This study utilizes the National Health and Nutrition Examination Survey (NHANES) 2017-2018 data to explore the relationship between exposure to perfluoroalkyl substances (specifically perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), metals lead (Pb), mercury (Hg), and cadmium (Cd), allostatic load, and hepatic disease markers, including the fatty liver index a measure of the likelihood of non-alcoholic fatty liver disease, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin. The paper identified significant associations and interaction effects by employing descriptive statistics, Spearman's correlation analysis, linear regression, and Bayesian kernel machine regression (BKMR). Descriptive statistics highlight sex-specific differences in contaminant levels. Spearman's analysis underscores strong correlations among metals and per- and polyfluoroalkyl substances (PFAS). Linear regression reveals significant impacts of specific contaminants on AST, ALT, ALP, and bilirubin levels, adjusting for age and alcohol consumption. BKMR results further elucidate the complex, potentially synergistic relationships between these environmental exposures and the likelihood of non-alcoholic fatty liver disease, offering nuanced insights into their combined effects on liver health. The findings emphasize the intricate dynamics of environmental exposures on hepatic function, advocating for targeted public health interventions.

Personal Strategies to Reduce the Cardiovascular Impacts of Environmental Exposures

Ubiquitous environmental exposures increase cardiovascular disease risk via diverse mechanisms. This review examines personal strategies to minimize this risk. With regard to fine particulate air pollution exposure, evidence exists to recommend the use of portable air cleaners and avoidance of outdoor activity during periods of poor air quality. Other evidence may support physical activity, dietary modification, omega-3 fatty acid supplementation, and indoor and in-vehicle air conditioning as viable strategies to minimize adverse health effects. There is currently insufficient data to recommend specific personal approaches to reduce the adverse cardiovascular effects of noise pollution. Public health advisories for periods of extreme heat or cold should be observed, with limited evidence supporting a warm ambient home temperature and physical activity as strategies to limit the cardiovascular harms of temperature extremes. Perfluoroalkyl and polyfluoroalkyl substance exposure can be reduced by avoiding contact with perfluoroalkyl and polyfluoroalkyl substance-containing materials; blood or plasma donation and cholestyramine may reduce total body stores of perfluoroalkyl and polyfluoroalkyl substances. However, the cardiovascular impact of these interventions has not been examined. Limited utilization of pesticides and safe handling during use should be encouraged. Finally, vasculotoxic metal exposure can be decreased by using portable air cleaners, home water filtration, and awareness of potential contaminants in ground spices. Chelation therapy reduces physiological stores of vasculotoxic metals and may be effective for the secondary prevention of cardiovascular disease.

Temporal Trend of Serum Perfluorooctanoic Acid and Perfluorooctane Sulfonic Acid among U.S. Adults with or without Comorbidities in NHANES 1999-2018

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are associated with adverse health effects. This study examined the trend of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) levels in individuals with and without pre-existing comorbidities. We analyzed the characteristics of 13,887 participants across nine U.S. NHANES cycles (1999-2000 to 2017-2018) and calculated the geometric mean (GM) of PFOA and PFOS levels, standardized by sex and age. A joinpoint regression model was used to analyze the temporal trends of serum PFOA and PFOS levels. We observed declining PFOA and PFOS serum levels among adults in NHANES from 1999-2000 to 2017-2018. Serum PFOA and PFOS concentrations were higher in men, smokers, and individuals with pre-existing CKD, hyperlipidemia, CVD, and cancer. We observed faster decline rates in PFOA levels among individuals with diabetes and CKD and faster decline rates in PFOS levels among individuals with diabetes and those without CKD. This study provided evidence of varying levels and changing trends of PFOA and PFOS between groups with and without established chronic disease, highlighting the role of environmental chemicals in the onset and development of chronic diseases.

Electrochemical Reduction of Perfluorooctanoic Acid (PFOA): An Experimental and Theoretical Approach

Perfluorooctanoic acid (PFOA) is an artificial chemical of global concern due to its high environmental persistence and potential human health risk. Electrochemical methods are promising technologies for water treatment because they are efficient, cheap, and scalable. The electrochemical reduction of PFOA is one of the current methodologies. This process leads to defluorination of the carbon chain to hydrogenated products. Here, we describe a mechanistic study of the electrochemical reduction of PFOA in gold electrodes. By using linear sweep voltammetry (LSV), an E0' of -1.80 V vs Ag/AgCl was estimated. Using a scan rate diagnosis, we determined an electron-transfer coefficient (αexp) of 0.37, corresponding to a concerted mechanism. The strong adsorption of PFOA into the gold surface is confirmed by the Langmuir-like isotherm in the absence (KA = 1.89 × 1012 cm3 mol-1) and presence of a negative potential (KA = 3.94 × 107 cm3 mol-1, at -1.40 V vs Ag/AgCl). Based on Marcus-Hush's theory, calculations show a solvent reorganization energy (λ0) of 0.9 eV, suggesting a large electrostatic repulsion between the perfluorinated chain and water. The estimated free energy of the transition state of the electron transfer (ΔG‡ = 2.42 eV) suggests that it is thermodynamically the reaction-limiting step. 19F - 1H NMR, UV-vis, and mass spectrometry studies confirm the displacement of fluorine atoms by hydrogen. Density functional theory (DFT) calculations also support the concerted mechanism for the reductive defluorination of PFOA, in agreement with the experimental values.

Lactational exposure to perfluorooctane sulfonate remains a potential risk in brain function of middle-aged male mice

Perfluorooctane sulfonate (PFOS) exerts adverse effects on neuronal development in young population. Limited evidences have shown that early-life PFOS exposure holds a potential risk for developing age-related neurodegenerative diseases such as Alzheimer's disease later in life. The present study investigated the effects of lactational PFOS exposure on cognitive function using one-year-old mice. Dams were exposed to PFOS (1 mg/kg body weight) through lactation by gavage. Male offspring were used for the behavior test battery to assess cognitive function. Western blot analysis was conducted to measure the levels of proteins related to the pathogenesis of Alzheimer's disease. PFOS-exposed mice displayed a mild deficiency in social recognition. In the hippocampus, the expression of tau protein was significantly increased. These results underline a mild effect of developing PFOS exposure on cognitive function and neurodegeneration. The present study presents the long-lasting effects of PFOS in middle-aged period and warrants a potential aftermath.

Characterizing Volatile Emissions and Combustion Byproducts from Aqueous Film-Forming Foams Using Online Chemical Ionization Mass Spectrometry

Aqueous film-forming foams (AFFFs) are used in firefighting applications and often contain per- and polyfluoroalkyl substances (PFAS), which can detrimentally impact environmental and biological health. Incineration is a potential disposal method for AFFFs, which may produce secondary PFAS and other air pollutants. We used online chemical ionization mass spectrometry (CIMS) to measure volatile PFAS emissions from incinerating AFFF concentrate solutions. We quantified perfluorinated carboxylic acids (PFCAs) during the incineration of legacy and contemporary AFFFs. These included trifluoroacetic acid, which reached mg m-3 quantities in the incinerator exhaust. These PFCAs likely arose as products of incomplete combustion of AFFF fluorosurfactants with lower peak furnace temperatures yielding higher PFCA concentrations. We also detected other short-chain PFAS, and other novel chemical products in AFFF combustion emissions. The volatile headspace above AFFF solutions contained larger (C ≥ 8), less oxidized PFAS detected by CIMS. We identified neutral PFAS resembling fluorotelomer surfactants (e.g., fluorotelomer sulfonamide alkylbetaines and fluorotelomer thioether amido sulfonates) and fluorotelomer alcohols in contemporary AFFF headspaces. Directly comparing the distinct chemical spaces of AFFF volatile headspace and combustion byproducts as measured by CIMS provides insight toward the chemistry of PFAS during thermal treatment of AFFFs.

Association of per- and polyfluoroalkyl substances (PFAS) with periodontitis: the mediating role of sex hormones

OBJECTIVES

To investigate the association between serum per- and polyfluoroalkyl substances (PFAS) and periodontitis, and further explore the possible mediating role of sex hormones in this association.

METHODS

We extracted data from National Health and Nutrition Examination Survey (NHANES) 2009-2014. Univariable and multivariable logistic regression models were performed to investigate the association between serum levels of seven PFASs and periodontitis. Bayesian kernel machine regression (BKMR) was conducted to assess the joint effect of PFASs in mixtures. Mediation analyses were used to explore the potential mediating role of sex hormones.

RESULTS

Participants with periodontitis had higher concentrations of serum perfluorooctane sulfonate (PFOS) and perfluorononanoic acid (PFNA) than those without periodontitis (both P < 0.05). In fully adjusted models, high serum concentrations of PFOS and PFNA were positively associated with periodontitis (tertile 3 vs. tertile 1: prevalence ratio (PR) = 1.19 for PFOS, 95% CI: 1.01-1.39; PR = 1.17 for PFNA, 95% CI: 1.02-1.34). The results from the BKMR models consistently showed a positive association between PFAS mixtures and periodontitis. Of note, testosterone and the ratio of testosterone to estradiol significantly mediated the relationship between high level of PFOS and periodontitis, accounting for 16.5% and 31.7% of the total effect, respectively. Sensitivity analyses yielded similar results when using periodontal clinical indices (mean loss of attachment, mean periodontal probing depth, and the number of teeth) as dependent variables.

CONCLUSIONS

These findings provide evidence to support a positive association between certain PFASs and periodontitis, which might be partially mediated by sex hormones.

A Non-Bonding Interaction-Based Fluorescent Probe for Detection of Halogenated Carbonyl Compounds

The fluorescent detection of neutral and volatile carbonyl halogenated compounds had not been studied before. We describe here a simple and sensitive turn-on rhodamin fluorescent probe for the selective detection of fluorinated/brominated/chlorinated/iodinated carbonyl compounds. A wide range of linear or cyclic volatile organic halides was detected with a limit of detection as low as 45.6 nM within 1 min. Mechanistic experiments and DFT calculations indicate the reversible formation of a 1:1 complex of sensor and analyst through non-bonding interaction.

Is it raining PFAS in France? An analysis of 52 PFAS at nanogram per liter levels in French rainwaters during autumn season

Per- and polyfluoroalkyl substances (PFAS) are of increasing concern due to their pervasive nature, high persistence, and their impacts on human health and the environment. Many studies have attempted to assess the presence of PFAS along the water cycle, but few have analyzed rainwater PFAS content and its contribution to water contamination. The present study aims to improve knowledge by providing the first analysis of PFAS rainwater samples from France. A total of 52 PFAS were analyzed at nanogram per liter levels in rainwater samples collected in 14 locations in France using a cutting-edge liquid chromatography-tandem mass spectrometry (LC/MS/MS) method for multiresidue determination. Depending on the quantity of rainwater collected, the PFAS concentrations were analyzed either by direct injection or after solid-phase extraction (SPE), allowing to quantify 20 PFAS with a limit of quantification (LOQ) ≤ 100 ng/L and 52 PFAS with a LOQ ≤ 1 ng/L, respectively. For the five locations for which the collected samples were analyzed by direct injection, no PFAS could be detected (i.e., their concentrations in the samples were below the LOQs of the method). The samples from four locations out of the nine analyzed by SPE-LC/MS/MS show results above the method's LOQs for up to 10 PFAS. Among the quantified PFAS, three compounds (perfluorononanoic acid, perfluoroundecanoic acid, and perfluorohexanoic acid) have been found to be of most significance. These results bring out the presence of PFAS in rainwater samples in France, highlighting the need for PFAS environmental surveillance and risk assessment and the necessity of continuous improvement of existing analysis methods.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

IMPACT

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

The sources and bioaccumulation of per- and polyfluoroalkyl substances in animal-derived foods and the potential risk of dietary intake

Per- and polyfluoroalkyl substances (PFAS) have attracted increasing attention due to their environmental persistence and potential toxicity. Diet is one of the main routes of human exposure to PFAS, particularly through the consumption of animal-derived foods (e.g., aquatic products, livestock and poultry, and products derived from them). This review summarizes the source, bioaccumulation, and distribution of PFAS in animal-derived foods and key influential factors. In most environmental media, perfluorooctanoic acid and perfluorooctane sulfonate are the dominant PFAS, with the levels of short-chain PFAS such as perfluorobutyric acid and perfluorohexane sulfonate surpassing them in some watersheds and coastal areas. The presence of PFAS in environmental media is mainly influenced by suspended particulate matter, microbial communities as well as temporal and spatial factors, such as season and location. Linear PFAS with long carbon chains (C ≥ 7) and sulfonic groups tend to accumulate in organisms and contribute significantly to the contamination of animal-derived foods. Furthermore, PFAS, due to their protein affinity, are prone to accumulate in the blood and protein-rich tissues such as the liver and kidney. Species differences in PFAS bioaccumulation are determined by diet, variances in protein content in the blood and tissues and species-specific activity of transport proteins. Carnivorous fish usually show higher PFAS accumulation than omnivorous fish. Poultry typically metabolize PFAS more rapidly than mammals. PFAS exposures in the processing of animal-derived foods are also attributable to the migration of PFAS from food contact materials, especially those in higher-fat content foods. The human health risk assessment of PFAS exposure from animal-derived foods suggests that frequent consumption of aquatic products potentially engender greater risks to women and minors than to adult males. The information and perspectives from this review would help to further identify the toxicity and migration mechanism of PFAS in animal-derived foods and provide information for food safety management.

Perfluorooctanoic acid induces behavioral impairment and oxidative injury in Nauphoeta cinerea nymphs

Perfluorooctanoic acid (PFOA) is a persistent organic contaminant with potential health threats to both animals and humans. However, the impact of PFOA on insects, which play significant roles in ecosystems, is understudied. We evaluated the toxicological impact of ecologically relevant concentrations of PFOA (0, 25, 50, 100, and 200 µg L-1) on Nauphoeta cinerea nymphs following exposure for 42 consecutive days. We analyzed the behavior of the insects with automated video-tracking software and processed the head, midgut, and fat body for biochemical assays. PFOA-exposed insects exhibited significant reductions in locomotory abilities and an increase in freezing time. Furthermore, PFOA exposure reduced acetylcholinesterase activity in the insect head. PFOA exposure increased the activities of superoxide dismutase, glutathione peroxidase, and catalase in the head and midgut, but decreased them in the fat body. PFOA also significantly increased glutathione-S transferase activity, while decreasing glutathione levels in the head, midgut, and fat body. Additionally, PFOA exposure increased reactive oxygen and nitrogen species, nitric oxide, lipid peroxidation, and protein carbonyl contents in the head, midgut, and fat body of the insects. In conclusion, our findings indicate that PFOA exposure poses an ecological risk to Nauphoeta cinerea.

Serum albumin mitigated perfluorooctane sulfonate-induced cytotoxicity by affecting the cellular responses

During the wide applications of perfluorinated materials such as perfluorooctane sulfonate (PFOS) in commercial and industrial products, the potential toxicity of these engineered compounds has attracted more and more attention. As a typical environmental pollutant, PFOS could preferentially bind to albumin protein in vivo. However, the role of protein-PFOS interactions in the cytotoxicity of PFOS was not stressed enough. Herein, we investigated the interactions of PFOS with human serum albumin (HSA, the most abundant protein in human plasma) using both experimental and theoretical approaches. It was demonstrated that PFOS could mainly bind to the Sudlow site I of HSA to generate HSA-PFOS complex through hydrogen bonds and van der Waals forces. Toxicity assays with endothelial cells illustrated that the binding of HSA could significantly attenuate the intracellular uptake and subcellular distribution of PFOS, thereby inhibiting the formation of reactive oxygen species and toxicity for those HSA-bound PFOS. Similarly, the presence of fetal bovine serum in the cell culture media greatly reduced PFOS-caused cytotoxicity. Conclusively, our study reveals that the binding of albumin protein to PFOS could mitigate its toxicity by the modulation of cellular responses. The formation of protein-complexed contaminants would significantly reduce the bioavailability of these chemicals and subsequently mitigate their environmental toxicology to the human health.

Research Progress of Perfluoroalkyl Substances in Edible Oil-A Review

Perfluoroalkyl substances (PFASs) have been widely used in different types of consumer and industrial applications such as surfactants, household cleaning products, textiles, carpets, cosmetics, firefighting foams, and food packaging because of their good stability and special physicochemical properties of hydrophobicity, oleophobicity, high temperature resistance, etc. Meanwhile, PFASs are considered an emerging organic pollutant due to their persistence and potential toxicity to human health. PFASs occur in edible oil, an important component of the global diet, mainly in three ways: raw material contamination, process contamination, and migration from oil contact materials. Thus, the occurrence of PFAS in edible oils has drawn more and more attention in recent years. In this work, the pertinent literature of the last two decades from the Web of Science database was researched. This review systematically addressed the potential sources, the contamination levels, and the progress of the determination of PFASs in edible oil. It aims to provide a relatively whole profile of PFASs in edible oil, render assistance to minimise human exposure to PFASs, and standardise the detection methods of perfluoroalkyl substances in edible oil.

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

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

Perfluorooctanoic acid (PFOA) exposure in relation to the kidneys: A review of current available literature

Perfluorooctanoic acid is an artificial and non-degradable chemical. It is widely used due to its stable nature. It can enter the human body through food, drinking water, inhalation of household dust and contact with products containing perfluorooctanoic acid. It accumulates in the human body, causing potential harmful effects on human health. Based on the biodegradability and bioaccumulation of perfluorooctanoic acid in the human body, there are increasing concerns about the adverse effects of perfluorooctanoic acid exposure on kidneys. Research shows that kidney is the main accumulation organ of Perfluorooctanoic acid, and Perfluorooctanoic acid can cause nephrotoxicity and produce adverse effects on kidney function, but the exact mechanism is still unknown. In this review, we summarize the relationship between Perfluorooctanoic acid exposure and kidney health, evaluate risks more clearly, and provide a theoretical basis for subsequent research.

Implications of the changing epidemiology of inflammatory bowel disease in a changing world

The epidemiology of inflammatory bowel disease (IBD) has undergone considerable shifts since its emergence in the Western world over a century ago, especially in the last few decades, with increasing global burden of disease. IBD incidence continues to rise in developed countries in all age groups which is contributing to compounding prevalence. Further, IBD incidence is rising sharply in Asia and other recently developed and developing countries. In this review, we discuss the implications of changing trends of IBD epidemiology. First, changing patterns provide insights into IBD causes, as they occur concurrent with shifts in the environment, cultures, and attitudes. Understanding the impact of the environment on IBD risk can help towards prediction and prevention strategies. Second, we must prepare healthcare systems for the rising burden of IBD and address it at various levels towards improving outcomes and health, overall.

An Overview of Chemical Additives on (Micro)Plastic Fibers: Occurrence, Release, and Health Risks

Plastic fibers are ubiquitous in daily life with additives incorporated to improve their performance. Only a few restrictions exist for a paucity of common additives, while most of the additives used in textile industry have not been clearly regulated with threshold limits. The production of synthetic fibers, which can shed fibrous microplastics easily (< 5 mm) through mechanical abrasion and weathering, is increasing annually. These fibrous microplastics have become the main composition of microplastics in the environment. This review focuses on additives on synthetic fibers; we summarized the detection methods of additives, compared concentrations of different additive types (plasticizers, flame retardants, antioxidants, and surfactants) on (micro)plastic fibers, and analyzed their release and exposure pathways to environment and human beings. Our prediction shows that the amounts of predominant additives (phthalates, organophosphate esters, bisphenols, per- and polyfluoroalkyl substances, and nonylphenol ethoxylates) released from clothing microplastic fibers (MFs) are estimated to reach 35, 10, 553, 0.4, and 568 ton/year to water worldwide, respectively; and 119, 35, 1911, 1.4, and 1965 ton/year to air, respectively. Human exposure to MF additives via inhalation is estimated to be up to 4.5–6440 µg/person annually for the above five additives, and via ingestion 0.1–204 µg/person. Notably, the release of additives from face masks is nonnegligible that annual human exposure to phthalates, organophosphate esters, per- and polyfluoroalkyl substances from masks via inhalation is approximately 491–1820 µg/person. This review helps understand the environmental fate and potential risks of released additives from (micro)plastic fibers, with a view to providing a basis for future research and policy designation of textile additives.