Ubiquitous Occurrence of Fluorotelomer Alcohols in Eco-Friendly Paper-Made Food-Contact Materials and Their Implication for Human Exposure

Identification and quantification of per- and polyfluorinated alkyl substances (PFAS) migrating from food contact materials (FCM)

Per- and polyfluorinated alkyl substances (PFAS) can be added to food contact materials (FCM) to increase their water and/or grease repellent properties. Some well-known PFAS are perfluoroalkyl carboxylic acids (PFCA), perfluoroalkyl sulfonic acids (PFSA), and polyfluorinated telomer alcohols (FTOH). Due to the strength of the carbon-fluorine bond, PFAS are chemically very stable and highly resistant to biological degradation, posing a risk to human health and the environment. To examine the presence of PFAS in paper-based FCM, various samples were collected, including popcorn bags, muffin cups, and pizza boxes with high total organic fluorine (TOF) content from the Danish and Spanish markets. The FCM composition was characterised by FTIR. Quantification of some well-known PFAS such as PFCA, PFSA, and FTOH was performed in food simulants using LC-MS/MS, and in addition a non-targeted screening approach was performed by LC-Orbitrap-HRMS. Among analysed samples, the highest concentrations of PFAS were found in a muffin cup made of cellulose (PFCA ∼ 1.41 μg kg-1 food, FTOH ∼ 11.5 μg kg-1 food), and the results were used to estimate dietary exposures to PFAS migrated from this FCM. Compared to measured TOF value in this sample, the fluorine from all quantified PFAS accounted for only 0.6%. Thus, a more powerful analytical approach was used to further investigate PFAS occurrence in this sample. Using non-targeted screening, an additional twenty compounds were identified, among them five with confidence level 1 and ten with confidence level 2. Many of them were either fluorotelomer carboxylic acids or sulfonic acids or ether-containing compounds.

External liquid calibration method for iodide chemical ionization mass spectrometry enables quantification of gas-phase per- and polyfluoroalkyl substances (PFAS) dynamics in indoor air

Per- and polyfluoroalkyl substances (PFAS) are manufactured chemicals that have been detected across the globe. Fluorotelomer alcohols (FTOHs) are one PFAS class commonly found in indoor air due to emissions from consumer products (e.g., textiles and food packaging) and are human metabolic, atmospheric oxidative, and industrial precursors of perfluoroalkyl carboxylic acids (PFCAs). We developed a quantitative method for real-time analysis of gas-phase FTOHs, perfluoroalkyl acids (PFCAs and GenX), one perfluorooctane sulfonamide (EtFOSA), one fluorotelomer diol (FTdiOH), and one fluorinated ether (E2) using high-resolution time-of-flight chemical ionization mass spectrometry equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Herein, we present a direct liquid injection method for external calibration, providing detection limits of 0.19-3.1 pptv for 3 s averaging and 0.02-0.44 pptv for 120 s averaging, with the exception of E2, which had detection limits of 1700 and 220 pptv for 3- and 120 s averaging, respectively. These calibrations enabled real-time gas-phase quantification of 6 : 2 FTOH in room air while microwaving popcorn, with an average peak air concentration of 31.6 ± 4.5 pptv measured 2 meters from a closed microwave. Additionally, 8 : 2 and 10 : 2 FTOH concentrations in indoor air were measured in the presence and absence of a rain jacket, with observed peak concentrations of 110 and 25 pptv, respectively. Our work demonstrates the ability of I-HR-ToF-CIMS to provide real-time air measurements of PFAS relevant to indoor human exposure settings and allow for PFAS source identification. We expect that real-time quantification of other gas-phase PFAS classes is possible, enabling advances in understanding PFAS sources, chemistry, and partitioning.

Emerging contaminants in food matrices: An overview of the occurrence, pathways, impacts and detection techniques of per- and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) have been used in industrial and consumer applications for ages. The pervasive and persistent nature of PFAS in the environment is a universal concern due to public health risks. Experts acknowledge that exposure to high levels of certain PFAS have consequences, including reduced vaccine efficacy, elevated cholesterol, and increased risk of high blood pressure. While considerable research has been conducted to investigate the presence of PFAS in the environment, the pathways for human exposure through food and food packaging/contact materials (FCM) remain unclear. In this review, we present an exhaustive overview of dietary exposure pathways to PFAS. Also, the mechanism of PFAS migration from FCMs into food and the occurrence of PFAS in certain foods were considered. Further, we present the analytical techniques for PFAS in food and food matrices as well as exposure pathways and human health impacts. Further, recent regulatory actions working to set standards and guidelines for PFAS in food packaging materials were highlighted. Alternative materials being developed and evaluated for their safety and efficacy in food contact applications, offering promising alternatives to PFAS were also considered. Finally, we reported on general considerations and perspectives presently considered.

Investigating the sources and fate of per- and polyfluoroalkyl substances (PFAS) in food waste compost

Composting municipal food waste is a key strategy for beneficially reusing methane-producing waste that would otherwise occupy landfill space. However, land-applied compost can cycle per- and polyfluoroalkyl substances (PFAS) back into the food supply and the environment. We partnered with a pilot-scale windrow composting facility to investigate the sources and fate of 40 PFAS in food waste compost. A comparison of feedstock materials yielded concentrations of ∑PFAS under 1 ng g-1 in mulch and food waste and at 1380 ng g-1 in leachate from used compostable food contact materials. Concentrations of targeted ∑PFAS increased with compost maturity along the windrow (1.85-23.1 ng g-1) and in mature stockpiles of increasing curing age (12.6-84.3 ng g-1). Among 15 PFAS quantified in compost, short-chain perfluorocarboxylic acids (PFCAs) - C5 and C6 PFCAs in particular - led the increasing trend, suggesting biotransformation of precursor PFAS into these terminal PFAS through aerobic decomposition. Several precursor PFAS were also measured, including fluorotelomer carboxylic acids (FTCAs) and polyfluorinated phosphate diesters (PAPs). However, since most targeted analytical methods and proposed regulations prioritize terminal PFAS, testing fully matured compost would provide the most relevant snapshot of PFAS that could be land applied. In addition, removing co-disposed food contact materials from the FW feedstock onsite yielded only a 37 % reduction of PFAS loads in subsequent compost, likely due to PFAS leaching during co-disposal. Source-separation of food contact materials is currently the best management practice for meaningful reduction of PFAS in food waste composts intended for land application.

Analysis of per- and polyfluoroalkyl substances (PFAS) in raw materials intended for the production of paper-based food contact materials - evaluating LC-MS/MS versus total fluorine and extractable organic fluorine

Per- and polyfluoroalkyl substances (PFAS) analysis has become crucial due to their presence in the environment, their persistence and potential health risks. These compounds are commonly used in food contact materials (FCM) as a coating to provide water and grease-repellent properties. One of the pathways for PFAS to enter the human body is either through direct consumption of contaminated food or indirectly through migration from FCM into food. The purpose of this study was to investigate where the initial contamination of paper FCM occurs. We analysed paper material consisting of fresh fibre and secondary materials, intended to produce food packaging for the presence of PFAS. The samples were extracted and analysed for 23 different PFAS substances using the targeted approach with LC tandem mass spectrometry (LC-MS/MS). This analytical technique detects specific, easily ionisable PFAS with high sensitivity. However, one drawback of this approach is that it allows the identification of less than 1% of the PFAS known today. For this reason, we used combustion ion chromatography (CIC) to determine the content of extractable organic fluorine compounds (EOF) and compare it to the total fluorine content. The targeted analysis using LC-MS/MS measured an average sum concentration of PFAS of 0.17 ng g-1 sample. Our research shows that the primary PFAS contamination happens during the recycling process since all of the samples in which the targeted PFAS were measured belonged to the secondary material. The most frequently detected analytes were PFOA and PFOS, detected in 90% and 62% of the samples, respectively, followed by PFBS (in 29% of the samples). CIC showed that measured PFAS via LC-MS/MS amount to an average of 2.7 × 10-4% of total fluorine content, whereas the EOF was under the LOD in all of the measured samples. This result highlights the complexity of the accurate determination of PFAS compounds, displaying what kind of information the chosen methods provide.

Predictors of Serum Per- and Polyfluoroalkyl Substances Concentrations among U.S. Couples Attending a Fertility Clinic

Previous studies have examined the predictors of PFAS concentrations among pregnant women and children. However, no study has explored the predictors of preconception PFAS concentrations among couples in the United States. This study included 572 females and 279 males (249 couples) who attended a U.S. fertility clinic between 2005 and 2019. Questionnaire information on demographics, reproductive history, and lifestyles and serum samples quantified for PFAS concentrations were collected at study enrollment. We examined the PFAS distribution and correlation within couples. We used Ridge regressions to predict the serum concentration of each PFAS in females and males using data of (1) socio-demographic and reproductive history, (2) diet, (3) behavioral factors, and (4) all factors included in (1) to (3) after accounting for temporal exposure trends. We used general linear models for univariate association of each factor with the PFAS concentration. We found moderate to high correlations for PFAS concentrations within couples. Among all examined factors, diet explained more of the variation in PFAS concentrations (1-48%), while behavioral factors explained the least (0-4%). Individuals reporting White race, with a higher body mass index, and nulliparous women had higher PFAS concentrations than others. Fish and shellfish consumption was positively associated with PFAS concentrations among both females and males, while intake of beans (females), peas (male), kale (females), and tortilla (both) was inversely associated with PFAS concentrations. Our findings provide important data for identifying sources of couples' PFAS exposure and informing interventions to reduce PFAS exposure in the preconception period.

Occurrence, behaviors, and fate of per- and polyfluoroalkyl substances (PFASs) in typical municipal solid waste disposal sites

Per- and polyfluoroalkyl substances (PFASs) have become a crucial environmental concern owing to their exceptional persistence, ability to bioaccumulate within ecosystems, and potential to adversely affect biota. Products and materials containing PFASs are usually discarded into municipal solid waste (MSW) at the end of their life cycle, and the fate of PFASs may differ when different disposal methods of MSWs are employed. To date, limited research has focus on the occurrence, behaviors, and fate of PFASs emitted from various MSW disposal sites. This knowledge gap may lead to an underestimation of the contribution of MSW disposal sites as a source of PFASs in the environment. In this review, we collated publications concerning PFASs from typical MSW disposal sites (i.e., landfills, incineration plants, and composting facilities) and explored the occurrence patterns and behaviors of PFASs across various media (e.g., landfill leachate/ambient air, incineration plant leachate/ash, and compost products) in these typical MSW disposal sites. In particular, this review highlighted ultrashort-chain perfluoroalkyl acids and "unknown"/emerging PFASs. Additionally, it meticulously elucidated the use of non-specific techniques and non-target analysis for screening and identifying these overlooked PFASs. Furthermore, the composition profiles, mass loads, and ecological risks of PFASs were compared across the three typical disposal methods. To the best of our knowledge, this is the first review regarding the occurrence, behaviors, and fate of PFASs in typical MSW disposal sites on a global scale, which can help shed light on the potential environmental impacts of PFASs harbored in MSWs and guide future waste management practices.

Phase transitions of fluorotelomer alcohols at the water|alkane interface studied via molecular dynamics simulation

Fluorosurfactants are long-lasting environmental pollutants that accumulate at interfaces ranging from aerosol droplet surfaces to cell membranes. Modeling of adsorption-based removal technologies for fluorosurfactants requires accurate simulation methods which can predict their adsorption isotherm and monolayer structure. Fluorotelomer alcohols with one or two methylene groups adjacent to the alcohol (7 : 1 FTOH and 6 : 2 FTOH, respectively) are investigated using the OPLS-AA force field at the water|hexane interface, varying the interfacial area per surfactant. The acquired interfacial pressure isotherms and monolayer phase behavior are compared with previous experimental results. The results are consistent with the experimental data inasmuch as, at realistic adsorption densities, only 7 : 1 FTOH shows a phase transition between liquid-expanded (LE) and 2D crystalline phases. Structures of the LE and crystalline phases are in good agreement with the sticky disc and Langmuir defective crystal models, respectively, used previously to interpret experimental data. Interfacial pressure of the LE phase agrees well with experiment, and sticky disc interaction parameters indicate no 2D LE-gas transition is present for either molecule. Conformation analysis reveals 7 : 1 FTOH favors conformers where the OH dipole is perpendicular to the molecular backbone, such that the crystalline phase is stabilized when these dipoles align.

Unveiling per- and polyfluoroalkyl substance contamination in Chinese paper products and assessing their exposure risk

The contamination characteristics, migration patterns and health risks of per- and polyfluoroalkyl substances (PFAS) were investigated in 66 Chinese paper products by using target and non-target screening methods. Among 57 target PFASs, 5 and 6 PFASs were found in the hygiene paper products ( Collapse

Key Words

• Migration
• Non-target analysis
• Paper products
• Per- and polyfluoroalkyl substances
• Risk assessment

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MESH Headings

• Humans
• Fluorocarbons/analysis
• Ethanol
• Food
• Food Safety
• China
• Alkanesulfonic Acids/analysis

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Affiliation(s)

Yan-Fei Chen SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China
Ting Liu SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China
Li-Xin Hu SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China
Chang-Er Chen SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China
Bin Yang SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China.
Guang-Guo Ying SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, Guangzhou 510006, China

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Assessing potential human health and ecological implications of PFAS from leave-in dental products

Contaminated water and food are the main sources of documented per- and polyfluoroalkyl substances (PFAS) exposure in humans. However, other sources may contribute to the overall PFAS intake. While several studies documented the presence of PFAS in consumer products, PFAS evaluation in dental products has been limited to floss and tape to date. This study estimated PFAS exposures from a convenience sample of leave-in dental products (night guards and whitening trays), which remain in contact with the mouth for longer durations than previously evaluated dental products. This analysis evaluated whether consumer usage of these dental products meaningfully contributes to oral exposure of PFAS. Leaching of PFAS upon disposal of products was also considered. Out of 24 PFAS measured, perfluorobutanoic acid (PFBA; 3.24-4.17 ng/product or 0.67-0.83 ng/g) and perfluorooctanesulfonic acid (PFOS; 7.25-16.45 ng/product or 1.2-2.3 ng/g) were detected in night guards, and no PFAS were detected in whitening trays. Non-targeted analysis showed additional possible PFAS, which could not be characterized. The findings showed that PFOS and/or PFBA present in night guards were unlikely to pose a health concern. From an ecological perspective, the dental products examined were shown to constitute a negligible contribution to environmental PFAS. In conclusion, the examined dental products do not represent a significant source of exposure to PFAS for humans or the environment. The study demonstrates how risk assessment can be integrated by the industry into product stewardship programs to evaluate the potential health and environmental impacts of chemicals in consumer products.

A critical review of perfluoroalkyl and polyfluoroalkyl substances (PFAS) landfill disposal in the United States

Landfills manage materials containing per- and polyfluoroalkyl substances (PFAS) from municipal solid waste (MSW) and other waste streams. This manuscript summarizes state and federal initiatives and critically reviews peer-reviewed literature to define best practices for managing these wastes and identify data gaps to guide future research. The objective is to inform stakeholders about waste-derived PFAS disposed of in landfills, PFAS emissions, and the potential for related environmental impacts. Furthermore, this document highlights data gaps and uncertainties concerning the fate of PFAS during landfill disposal. Most studies on this topic measured PFAS in liquid landfill effluent (leachate); comparatively fewer have attempted to estimate PFAS loading in landfills or other effluent streams such as landfill gas (LFG). In all media, the reported total PFAS heavily depends on waste types and the number of PFAS included in the analytical method. Early studies which only measured a small number of PFAS, predominantly perfluoroalkyl acids (PFAAs), likely report a significant underestimation of total PFAS. Major findings include relationships between PFAS effluent and landfill conditions - biodegradable waste increases PFAS transformation and leaching. Based on the results of multiple studies, it is estimated that 84% of PFAS loading to MSW landfills (7.2 T total) remains in the waste mass, while 5% leaves via LFG and 11% via leachate on an annual basis. The environmental impact of landfill-derived PFAS has been well-documented. Additional research is needed on PFAS in landfilled construction and demolition debris, hazardous, and industrial waste in the US.

Establishment of an Integrated Nontarget and Suspect Screening Workflow for Organophosphate Diesters (Di-OPEs) and Identification of Seven Previously Unknown Di-OPEs in Food Contact Plastics

In this study, an innovative, integrated nontarget and suspect screening workflow was developed for identifying organophosphate diesters (di-OPEs) using high-resolution mass spectrometry. The workflow featured the utilization of 0.02% acetic acid as a mobile-phase additive, differentiated screening methods for alkyl and aryl di-OPEs, and a combination of electrospray negative ionization and positive ionization. Using this workflow, 18 di-OPEs were identified in the extracts of 75 food contact plastic (FCP) samples sourced from South China. Among these, six alkyl and one aryl di-OPEs were previously unknown (one unequivocal identification and six probable structures based on diagnostic evidence). (Semi)quantification revealed that bis(2,4-di-tert-butylphenyl) phosphate was the major di-OPE in FCPs, with a median concentration of 1079 ng/g (range: 23.4-158,414 ng/g). The migration efficiencies of di-OPEs from an FCP sample to four kinds of food simulants were between 2.58 and 54.3%. This study offered a useful workflow for the comprehensive profiling of di-OPEs in FCPs.

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.

Nontarget Screening and Fate of Emerging Per- and Polyfluoroalkyl Substances in Wastewater Treatment Plants in Tianjin, China

Wastewater treatment plants (WWTPs) are typical point sources of per- and polyfluoroalkyl substances (PFAS) released into the environment. The suspect and nontarget screening based on gas chromatography or liquid chromatography-high resolution mass spectrometry were performed on atmosphere, wastewater, and sludge samples collected from two WWTPs in Tianjin to discover emerging PFAS and their fate in this study. A total of 40 PFAS (14 neutral and 26 ionic) and 64 PFAS were identified in the atmosphere and wastewater/sludge, respectively, among which 5 short-chain perfluoroalkyl sulfonamide derivatives, 4 ionic PFAS, and 15 aqueous film-forming foam-related cationic or zwitterionic PFAS have rarely or never been reported in WWTPs in China. Active air sampling is more conducive to the enrichment of emerging PFAS, while passive sampling is inclined to leave out some ultrashort-chain PFAS or unstable transformation intermediates. Moreover, most precursors and intermediates could be enriched in the atmosphere at night, while the PFAS associated with aerosols with high water content or particles enter the atmosphere easily during the day. Although most emerging PFAS could not be eliminated efficiently in conventional treatment units, deep bed filtration and advanced oxidation processes could partly remove some emerging precursors.

Measurement of fluorotelomer alcohols based on solid phase microextraction followed by gas chromatography-mass spectrometry and its application in solid waste study

This work developed a method based on solid phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS) for the measurement of fluorotelomer alcohols (FTOHs) in gas samples. The method quantification limit (MQL) is 6-7 ng/L for 6:2 fluorotelomer alcohols (6:2 FTOH) and 8:2 fluorotelomer alcohols (8:2 FTOH). In contrast to common methods such as thermal desorption combined with GC-MS, it needs neither pre-concentration equipment nor large sample volume. The extraction-evaporation-GC/MS is commonly used in literature for FTOHs measurement in solids samples. We developed a method to measure FTOHs in solid samples by adding solvent extraction prior to headspace SPME-GC/MS. The extraction-headspace SPME-GC/MS method has a quantification limit of 40-43 ng per gram for 6:2 FTOH and 8:2 FTOH in solid samples. This is comparable to the MQLs for the extraction-evaporation-GC/MS method. Removing the solvent evaporation step decreased the risk of contamination and loss of analytes. The developed methods were successfully used in three examples of solid waste study: 1) measuring 6:2 FTOH and 8:2 FTOH above the MQL in gas emissions from a closed landfill, 2) finding 6:2 FTOH above MQL in 9 of 31 solid consumer products, and 3) finding that the release of 6:2 FTOH in simulated landfills containing popcorn bags was linear at a rate of 3.15 ng/g popcorn bags-day and that partial 6:2 FTOH was from the hydrolysis of precursors.

Elevated Levels of Ultrashort- and Short-Chain Perfluoroalkyl Acids in US Homes and People

Per- and polyfluoroalkyl substances (PFAS) make up a large group of fluorinated organic compounds extensively used in consumer products and industrial applications. Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), the two perfluoroalkyl acids (PFAAs) with 8 carbons in their structure, have been phased out on a global scale because of their high environmental persistence and toxicity. As a result, shorter-chain PFAAs with less than 8 carbons in their structure are being used as their replacements and are now widely detected in the environment, raising concerns about their effects on human health. In this study, 47 PFAAs and their precursors were measured in paired samples of dust and drinking water collected from residential homes in Indiana, United States, and in blood and urine samples collected from the residents of these homes. Ultrashort- (with 2 or 3 carbons [C2-C3]) and short-chain (with 4-7 carbons [C4-C7]) PFAAs were the most abundant in all four matrices and constituted on average 69-100% of the total PFAA concentrations. Specifically, trifluoroacetic acid (TFA, C2) and perfluoropropanoic acid (PFPrA, C3) were the predominant PFAAs in most of the samples. Significant positive correlations (n = 81; r = 0.23-0.42; p < 0.05) were found between TFA, perfluorobutanoic acid (PFBA, C4), and perfluoroheptanoic acid (PFHpA, C7) concentrations in dust or water and those in serum, suggesting dust ingestion and/or drinking water consumption as important exposure pathways for these compounds. This study demonstrates that ultrashort- and short-chain PFAAs are now abundant in the indoor environment and in humans and warrants further research on potential adverse health effects of these exposures.

Perfluoroalkyl substances in food contact materials: preliminary investigation in Vietnam and global comparison

Per- and polyfluoroalkyl substances (PFASs) are a group of concerned persistent toxic substances, especially for their application or unintentional formation in food contact materials (FCMs). However, information about the occurrence, sources, and fate of these pollutants in food packaging materials from Vietnam as well as Southeast Asian countries is probably still obscured. In this study, levels of 13 perfluoroalkyl carboxylic acids (PFCAs) and 4 sulfonates (PFSs) were determined in various types of food packaging samples collected from Vietnamese markets. Generally low concentrations of total 17 PFASs (median 0.341; max 624 ng/g) suggested that these compounds were mainly inadvertently produced rather than intentionally added to the packaging materials. A few mochi paper tray samples had relatively high PFAS levels (372-624 ng/g), which were dominated by long-chain (C8-C12) PFCAs. A comprehensive and updated overview of PFASs in FCMs from different countries in the world was also provided. Current database could not provide conclusive trends of PFAS concentrations and profiles in FCMs between continents and countries. The highest levels up to ppm were reported for PFCAs (e.g., PFBA, PFHxA, PFOA, and PFDA) and several fluorotelomer alcohols and carboxylic acids, while PFSs were almost absent in FCMs. FPASs can emit from FCMs, migrate to food, and then contribute to dietary exposure in humans and animals. Additional investigations on the occurrence, sources, behavior and fate, and impacts of PFASs in FCMs are critically needed, especially in emerging and developing countries.

Rapid, efficient, and green analytical technique for determination of fluorotelomer alcohol in water by stir bar sorptive extraction

Fluorotelomer alcohols (FTOHs) are one of the major classes of per- and polyfluoroalkyl substances (PFAS). Due to their potential toxicity, persistence, and ubiquitous presence in the environment, some common PFAS are voluntarily phased out; while FTOHs are used as alternatives to conventional PFAS. FTOHs are precursors of perfluorocarboxylic acids (PFCAs) and therefore they are commonly detected in water matrices, which eventually indicate PFAS contamination in drinking water supplies and thus a potential source of human exposure. Even though studies have been conducted nationwide to evaluate the degree of FTOHs in the water environment, robust monitoring is lacking because of the unavailability of simple and sustainable analytical extraction and detection methods. To fill the gap, we developed and validated a simple, rapid, minimal solvent use, no clean-up, and sensitive method for the determination of FTOHs in water by stir bar sorptive extraction (SBSE) coupled with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Three commonly detected FTOHs (6:2 FTOH, 8:2 FTOH, and 10:2 FTOH) were selected as the model compounds. Factors such as extraction time, stirring speed, solvent composition, salt addition, and pH were investigated to achieve optimal extraction efficiency. This "green chemistry" based extraction provided good sensitivity and precision with low method limits of detection ranging from 2.16 ng/L to 16.7 ng/L and with an extraction recovery ranging 55%-111%. The developed method were tested on tap water, brackish water, and wastewater influent and effluent. 6:2 FTOH and 8:2 FTOH were detected in two wastewater samples at 78.0 and 34.8 ng/L, respectively. This optimized SBSE-TD-GC-MS method will be a valuable alternative to investigate FTOHs in water matrices.

Determination of several PFAS groups in food packaging material from fast-food restaurants in France

Per- and polyfluoroalkylated substances (PFAS) are a large group of toxic compounds which have been widely used in industrial and consumer applications, from where they can migrate into the environment. They can pose a risk to human health because they have been associated with several diseases. To obtain more information on the risk of PFAS in fast food packaging materials, several PFAS (perfluorocarboxylic acids or PFCAs (n = 16), perfluorosulfonic acids or PFSAs (n = 14), and a miscellaneous group constituted by sulfonamides (n = 5) and fluorotelomer phosphate esters or PAPs (n = 5)) were quantified in food contact materials (FCMs) from fast-food restaurants in France. Perfluorohexanoic acid (PFHxA), 6:2 fluorotelomer sulfonic acid (6:2 FTS) and 6:2/6:2 fluorotelomer phosphate diester (6:2/6:2 diPAP) were detected in all samples. PFCAs with shorter chain lengths (C4-C6) showed the highest concentrations compared to median (C7-C10) and longer chain length PFCAs (C11-C18). However, they had lower detection frequencies (DFs) (except for PFHxA, DF = 100%) with values of 36 and 34% for C4 and C5 PFCAs, respectively. The DF of longer chain length PFCAs was higher, especially those of the median chain length PFCAs (C8-C10, with DF = 79-98%). Analytes from the PFSA group with high DFs (70-98%) were perfluorobutane sulfonic acid (PFBS), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS, linear and branched) and 10:2 fluorotelomer sulfonic acid (10:2 FTS), with concentrations similar to some analytes from the PFCA group. 4:2 Fluorotelomer phosphate monoester (4:2 mPAP), 8:2 fluorotelomer phosphate monoester (8:2 mPAP) and 8:2/8:2 fluorotelomer phosphate diester (8:2/8:2 diPAP) were found with the highest concentrations (<0.006-42.7 ng g-1, <0.001-2.7 ng g-1 and <0.001-287 ng g-1, respectively) and the highest DFs (ranged 68-94%). Some correlations between analytes were found, indicating similar degradation routes or a common origin.

Non-extractable PFAS in functional textiles - characterization by complementary methods: oxidation, hydrolysis, and fluorine sum parameters

Per- and polyfluoroalkyl substances (PFAS) are widely used for durable water-repellent finishing of different fabrics and textiles such as outdoor clothing, carpets, medical textiles and more. Existing PFAS extraction techniques followed by target analysis are often insufficient for detecting widely used side-chain fluorinated polymers (SFPs) that are barely or non-extractable. SFPs are typically copolymers consisting of a non-fluorinated backbone with perfluoroalkyl side-chains to obtain desired properties. We compared the accessible analytical information and performance of complementary techniques based on oxidation (dTOP and PhotoTOP assays), hydrolysis (THP assay), standard extraction, extractable organic fluorine (EOF), and total fluorine (TF) with five functional textiles and characterized 7 further textiles only by PhotoTOP oxidation. The results show that when applied directly to textile samples, dTOP and PhotoTOP oxidation and also hydrolysis (THP) are able to capture large fractions of TF in the form of perfluoroalkyl side-chains present in the textiles while methods relying on extracts (EOF, target and non-target analysis) yield much lower fractions of TF (e.g., factor ∼25-50 lower). The conversion of large fractions of the measured TF into PFCAs or FTOHs from fluorinated side chains is in contrast to previous studies. Concentrations ranged from Collapse

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MESH Headings

• Fluorine
• Hydrolysis
• Textiles/analysis
• Fluorocarbon Polymers/analysis
• Fluorocarbon Polymers/chemistry
• Polymers
• Carboxylic Acids/analysis
• Fluorocarbons/analysis

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Affiliation(s)

Jonathan Zweigle Environmental Analytical Chemistry, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.
Catharina Capitain Environmental Analytical Chemistry, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.
Fabian Simon Federal Institute for Materials Research and Testing (BAM), Division 1.1 - Inorganic Trace Analysis, Richard-Willstätter-Straße 11, 12489 Berlin, Germany
Philipp Roesch Federal Institute for Materials Research and Testing (BAM), Division 4.3 - Contaminant Transfer and Environmental Technologies, Unter den Eichen 87, 12205, Berlin, Germany
Boris Bugsel Environmental Analytical Chemistry, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.
Christian Zwiener Environmental Analytical Chemistry, Department of Geosciences, University of Tübingen, Schnarrenbergstraße 94-96, 72076 Tübingen, Germany.

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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.

PFAS in municipal landfill leachate: Occurrence, transformation, and sources

To understand sources and processes affecting per- and polyfluoroalkyl substances (PFAS), 32 PFAS were measured in landfill leachate from 17 landfills across Washington State in both pre-and post-total oxidizable precursor (TOP) assay samples, using an analytical method that was the precursor to EPA Draft Method 1633. As in other studies, 5:3FTCA was the dominant PFAS in the leachate, suggesting that carpets, textiles, and food packaging were the main sources of PFAS. Total PFAS concentrations (Σ₃₂PFAS) ranged from 61 to 172,976 ng/L and 580-36,122 ng/L in pre-TOP and post-TOP samples, respectively, suggesting that little or no uncharacterized precursors remained in landfill leachate. Furthermore, due to chain-shortening reactions, the TOP assay often resulted in a loss of overall PFAS mass. Positive matrix factorization (PMF) analysis of the combined pre- and post-TOP samples produced five factors that represent sources and processes. Factor 1 consisted primarily of 5:3FTCA (intermediate of 6:2 fluorotelomer degradation and characteristic of landfill leachate), while factor 2 was dominated by PFBS (degradant of C-4 sulfonamide chemistry) and, to a lesser extent, by several PFCAs and 5:3FTCA. Factor 3 consisted primarily of both short-chain PFCAs (end-products of 6:2 fluorotelomer degradation) and PFHxS (derived from C-6 sulfonamide chemistry), while the main component of factor 4 was PFOS (dominant in many environmental media but minor in landfill leachate, perhaps reflecting a production shift from longer to shorter chain PFAS). Factor 5, highly loaded with PFCAs, was dominant in post-TOP samples and therefore represented the oxidation of precursors. Overall, PMF analysis suggests that the TOP assay approximates some redox processes which occur in landfills, including chain-shortening reactions which yield biodegradable products.

Category-Based Toxicokinetic Evaluations of Data-Poor Per- and Polyfluoroalkyl Substances (PFAS) using Gas Chromatography Coupled with Mass Spectrometry

Concern over per- and polyfluoroalkyl substances (PFAS) has increased as more is learned about their environmental presence, persistence, and bioaccumulative potential. The limited monitoring, toxicokinetic (TK), and toxicologic data available are inadequate to inform risk across this diverse domain. Here, 73 PFAS were selected for in vitro TK evaluation to expand knowledge across lesser-studied PFAS alcohols, amides, and acrylates. Targeted methods developed using gas chromatography-tandem mass spectrometry (GC-MS/MS) were used to measure human plasma protein binding and hepatocyte clearance. Forty-three PFAS were successfully evaluated in plasma, with fraction unbound (f_up) values ranging from 0.004 to 1. With a median f_up of 0.09 (i.e., 91% bound), these PFAS are highly bound but exhibit 10-fold lower binding than legacy perfluoroalkyl acids recently evaluated. Thirty PFAS evaluated in the hepatocyte clearance assay showed abiotic loss, with many exceeding 60% loss within 60 min. Metabolic clearance was noted for 11 of the 13 that were successfully evaluated, with rates up to 49.9 μL/(min × million cells). The chemical transformation simulator revealed potential (bio)transformation products to consider. This effort provides critical information to evaluate PFAS for which volatility, metabolism, and other routes of transformation are likely to modulate their environmental fates.

Health Risk Exposure Assessment of Migration of Perfluorooctane Sulfonate and Perfluorooctanoic Acid from Paper and Cardboard in Contact with Food under Temperature Variations

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are extensively used in food-contact paper and cardboard. However, they may migrate from food-contact materials to food, and the migration rate may be increased at elevated temperatures. In addition, there is a positive association of PFOS/PFOA levels with total cholesterol. Therefore, this study aims to assess the human health risk of increased total cholesterol associated with long-term exposure to PFOS and PFOA migration from food-contact paper and cardboard under temperature variation scenarios in adults. An exposure assessment was performed using an uptake dose model to estimate the uptake doses of PFOS and PFOA for the high-, intermediate-, and low-exposure scenarios. Benchmark dose (BMD) modeling was conducted to describe the dose-response relationships between PFOS/PFOA and total cholesterol levels. Finally, a margin of exposure (MOE) approach was used to characterize the risk. The results of the exposure assessment showed that PFOS and PFOA uptake doses in the high-exposure scenarios were around one and two orders of magnitude greater than those in the intermediate- and low-exposure scenarios, respectively. Under high-exposure scenarios, the uptake levels of hundredth-percentile PFOS and PFOA at high temperatures may raise health concerns (MOE < 1). This study provides a methodology to assess the health risks associated with exposure to migration of food contaminants from various types of paper and cardboard that come into contact with food.

Per- and Polyfluoroalkyl Substances in Canadian Fast Food Packaging

A suite of analytical techniques was used to obtain a comprehensive picture of per- and polyfluoroalkyl substances (PFAS) in selected Canadian food packaging used for fast foods (n = 42). Particle-induced gamma ray emission spectroscopy revealed that 55% of the samples contained <3580, 19% contained 3580-10 800, and 26% > 10 800 μg F/m2. The highest total F (1 010 000-1 300 000 μg F/m2) was measured in molded "compostable" bowls. Targeted analysis of 8 samples with high total F revealed 4-15 individual PFAS in each sample, with 6:2 fluorotelomer methacrylate (FTMAc) and 6:2 fluorotelomer alcohol (FTOH) typically dominating. Up to 34% of the total fluorine was released from samples after hydrolysis, indicating the presence of unknown precursors. Nontargeted analysis detected 22 PFAS from 6 different groups, including degradation products of FTOH. Results indicate the use of side-chain fluorinated polymers and suggest that these products can release short-chain compounds that ultimately can be transformed to compounds of toxicological concern. Analysis after 2 years of storage showed overall decreases in PFAS consistent with the loss of volatile compounds such as 6:2 FTMAc and FTOH. The use of PFAS in food packaging such as "compostable" bowls represents a regrettable substitution of single-use plastic food packaging.

Sources, Fate, and Detection of Dust-Associated Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS): A Review

The occurrence of sand and dust storms (SDSs) is essential for the geochemical cycling of nutrients; however, it is considered a meteorological hazard common to arid regions because of the adverse impacts that SDSs brings with them. One common implication of SDSs is the transport and disposition of aerosols coated with anthropogenic contaminants. Studies have reported the presence of such contaminants in desert dust; however, similar findings related to ubiquitous emerging contaminants, such as per- and poly-fluoroalkyl substances (PFAS), have been relatively scarce in the literature. This article reviews and identifies the potential sources of dust-associated PFAS that can accumulate and spread across SDS-prone regions. Furthermore, PFAS exposure routes and their toxicity through bioaccumulation in rodents and mammals are discussed. The major challenge when dealing with emerging contaminants is their quantification and analysis from different environmental media, and these PFAS include known and unknown precursors that need to be quantified. Consequently, a review of various analytical methods capable of detecting different PFAS compounds embedded in various matrices is provided. This review will provide researchers with valuable information relevant to the presence, toxicity, and quantification of dust-associated PFAS to develop appropriate mitigation measures.

Electrochemical-based approaches for the treatment of forever chemicals: Removal of perfluoroalkyl and polyfluoroalkyl substances (PFAS) from wastewater

Electrochemical based approaches for the treatment of recalcitrant water borne pollutants are known to exhibit superior function in terms of efficiency and rate of treatment. Considering the stability of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are designated as forever chemicals, which generating from various industrial activities. PFAS are contaminating the environment in small concentrations, yet exhibit severe environmental and health impacts. Electro-oxidation (EO) is a recent development that treats PFAS, in which different reactive species generates at anode due to oxidative reaction and reductive reactions at the cathode. Compared to water and wastewater treatment methods those being implemented, electrochemical approaches demonstrate superior function against PFAS. EO completely mineralizes (almost 100 %) non-biodegradable organic matter and eliminate some of the inorganic species, which proven as a robust and versatile technology. Electrode materials, electrolyte concentration pH and the current density applying for electrochemical processes determine the treatment efficiency. EO along with electrocoagulation (EC) treats PFAS along with other pollutants from variety of industries showed highest degradation of 7.69 mmol/g of PFAS. Integrated approach with other processes was found to exhibit improved efficiency in treating PFAS using several electrodes boron-doped diamond (BDD), zinc, titanium and lead based with efficiency the range of 64 to 97 %.

Dietary predictors of prenatal per- and poly-fluoroalkyl substances exposure

BACKGROUND

Per- and poly-fluoroalkyl substances (PFAS) are commonly detected in a variety of foods and food packaging materials. However, few studies have examined diet as a potential source of PFAS exposure during pregnancy. In the present cross-sectional study, we examined prenatal PFAS levels in relation to self-reported consumption of meats, dairy products, and processed foods during pregnancy.

METHODS

Participants were enrolled in the Chemicals in Our Bodies study, a demographically diverse pregnancy cohort in San Francisco, CA (N = 509). Diet was assessed using a self-reported interview questionnaire administered during the second trimester. Participants were asked on average how many times a day, week, or month they ate 11 different foods since becoming pregnant. Responses were categorized as at least once a week or less than once a week and foods were grouped into three categories: processed foods, dairy products, and meats. Twelve PFAS (ng/mL) were measured in second trimester serum samples. We investigated relationships between consumption of individual dairy products, meats, and processed foods and natural log-transformed PFAS using separate linear regression models adjusted for maternal age, education, race/ethnicity, and nativity.

RESULTS

Seven PFAS were detected in ≥65% of participants. Consumption of dairy milk and cheese at least once per week was moderately associated with elevated levels of perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDeA) relative to those who ate dairy products less than once week. The strongest associations observed were with PFDeA for dairy milk (β = 0.2, 95% confidence interval [CI] = 0.02, 0.39) and PFNA for cheese (β = 0.22, 95% CI = 0.02, 0.41). Eating fish, poultry, and red meat at least once per week was associated with higher levels of perfluoroundecanoic acid, PFDeA, PFNA, and perflucorooctane sulfonic acid.

CONCLUSIONS

Results indicate that consumption of animal products may contribute to elevated prenatal PFAS levels.

Perfluoroalkyl acid and bisphenol-A exposure via food sources in four First Nation communities in Quebec, Canada

OBJECTIVE

To document perfluoroalkyl acids (PFAA) and bisphenol-A (BPA) exposure in four First Nation communities in northern Quebec compared with the Canadian Health Measures Survey (CHMS Cycle 5 2016-2017) and examine the associations between dietary consumption and chemical exposure.

DESIGN

We used cross-sectional data from the JES-YEH! project conducted in collaboration with four First Nation communities in 2015. A FFQ collected information on diet, and PFAA and BPA were measured in biological samples. We used generalised linear models to test the associations between food intake and chemical biomarkers.

SETTING

Northern Quebec.

PARTICIPANTS

Youth aged 3-19 years (n 198).

RESULTS

Mean perfluorononanoic acid (PFNA) levels were significantly higher in JES-YEH! than CHMS, and BPA levels were higher among those aged 12-19 years compared with CHMS. Dairy products were associated with PFNA among Anishinabe and Innu participants (geometric mean ratio 95 % CI: 1·53 (95 % CI 1·03, 2·29) and 1·52 (95 % CI 1·05, 2·20), respectively). PFNA was also associated with ultra-processed foods (1·57 (95 % CI 1·07, 2·31)) among Anishinabe, and with wild fish and berries (1·44 (95 % CI 1·07, 1·94); 1·75 (95 % CI 1·30, 2·36)) among Innu. BPA was associated with cheese (1·72 (95 % CI 1·19, 2·50)) and milk (1·53 (95 % CI 1·02, 2·29)) among Anishinabe, and with desserts (1·71 (95 % CI 1·07, 2·74)), processed meats (1·55 (95 % CI 1·00, 2·38)), wild fish (1·64 (95 % CI 1·07, 2·49)) and wild berries (2·06 (95 % CI 1·37, 3·10)) among Innu.

CONCLUSIONS

These results highlight the importance of better documenting food-processing and packaging methods, particularly for dairy products, and their contribution to endocrine disruptors exposures as well as to promote minimally processed and unpackaged foods to provide healthier food environments for youth in Indigenous communities and beyond.

Discovery of 18 Organophosphate Esters and 3 Organophosphite Antioxidants in Food Contact Materials Using Suspect and Nontarget Screening: Implications for Human Exposure

In this study of extracts of 100 food contact material (FCM) samples collected from South China, we identified 21 organophosphate esters (OPEs) by suspect screening and seven novel OPEs by characteristic fragments-based nontarget screening. Six organophosphite antioxidants (OPAs) were further identified using a suspect list derived from these identified OPEs. Of these compounds, 18 OPEs and 3 OPAs were found for the first time in the extracts of FCMs. (Semi-)quantification revealed that seven of the OPEs [triphenyl phosphate, tris(2,4-di-tert-butylphenyl) phosphate (TDtBPP), bis(2,4-di-tert-butylphenyl) methyl phosphate, (2,4-di-tert-butylphenyl)pentaerythritol phosphate, triethyl phosphate, 2-ethylhexyl-diphenyl phosphate, and trimethyl phosphate] and two of the OPAs [tris(2,4-di-tert-butylphenyl) phosphite (TDtBPPi) and pentabutylated triphenyl phosphite] were present in more than 50 FCM samples and that TDtBPP and TDtBPPi were the dominant OPE and OPA in FCMs, respectively [with median concentrations of 7260 ng/g (range: <8.50-103,879 ng/g) and 31,920 ng/g (range: <9.80-657,399 ng/g), respectively]. A migration test revealed that the migration efficiencies of compounds from a plastic coffee cup to food simulants in the cup increased as the ethanol/water ratio in the food simulants increased. This study significantly enhanced our understanding on the diversity and occurrences of OPEs and OPAs in FCMs used in China and their FCM-to-food migration risk.

Use and release of per- and polyfluoroalkyl substances (PFASs) in consumer food packaging in U.S. and Canada

Numerous per- and polyfluoroalkyl substances (PFASs) occur in consumer food packaging due to intentional and unintentional addition, despite increasing concern about their health and environmental hazards. We present a substance flow analysis framework to assess the flows of PFASs contained in plant fiber-based and plastic food packaging to the waste stream and environment. Each year between 2018 and 2020, an estimated 9000 (range 1100-25 000) and 940 (range 120-2600) tonnes per year of polymeric PFASs were used in 2% of food packaging in the U.S. and Canada, respectively. At least 11 tonnes per year of non-polymeric PFASs also moved through the food packaging life cycle. Approximately 6100 (range 690-13 000) and 700 (range 70-1600) tonnes per year of these PFASs were landfilled or entered composting facilities in the U.S. and Canada, respectively, with the potential to contaminate the environment. The results suggest that minimal food packaging contains intentionally added PFASs which, nonetheless, has the potential to contaminate the entire waste stream. Further, this indicates that PFASs are not needed for most food packaging. These results serve as a benchmark to judge the effectiveness of future industry and government initiatives to limit PFAS use in food packaging.

Occurrence of Perfluoroalkyl and Polyfluoroalkyl Substances in Ice Cream, Instant Noodles, and Bubble Tea

Food consumption is a significant exposure route to perfluoroalkyl and polyfluoroalkyl substances (PFAS). The concentrations of 27 PFAS in fast food were determined by ultrahigh-performance liquid chromatography-high resolution mass spectrometry. In ice cream, instant noodles, and bubble tea, some PFAS were detected, among which perfluorooctanoic acid, perfluoro-n-butanoic acid, and 6:2 polyfluoroalkyl phosphate monoester showed relatively high concentrations. PFAS migrating from bubble tea cups to the food simulant of 50% ethanol aqueous solution showed a difference compared with those migrating into bubble tea matrices. The migration of 27 PFAS to bubble tea samples indicated that long storage time increased PFAS levels (up to 4.8 times) and so did high storage temperature (up to 7.3 times). The hazard ratio, defined as the ratio of the estimated daily intake and the reference dose, was calculated, and it suggests that the total PFAS exposure risk due to consumption of bubble tea should be of concern.

Investigating the cytotoxicity of per- and polyfluoroalkyl substances in HepG2 cells: A structure-activity relationship approach

Per- and polyfluoroalkyl substances (PFAS) are a family of man-made chemicals with currently over 4'700 compounds identified. While toxicological data are available for some of the legacy PFAS, such as PFOA and PFOS, a knowledge gap remains concerning both emerging and legacy PFAS' toxicity due to the diversity of the PFAS. Therefore, a better understanding of the PFAS structure-activity relationship may prove helpful. The present study investigated a potential structure-activity relationship between PFAS and hepatotoxicity. As such, the effects of thirteen PFAS with varying carbon chain-length and functional head-groups (in a concentration range of 0-800 µM) on the cell viability of HepG2 cells and intracellular reactive oxygen species formation have been tested using the MTT and DCFH assay, respectively. The exposure times were either 3 or 24 h. In addition, intracellular PFAS levels were determined in HepG2 after 24 h exposure. The present study demonstrated that the cytotoxicity of PFAS is dependent on their chain-length as cell viability decreased with increasing chain-length at both exposure times. Calculated Relative Potency Factors (RPF), based on the TC₅₀ values, were used for a tentative ranking of PFAS regarding their hepatotoxicity: PFNA ˃ PFDA ˃ PFOS ≥ PFOA ˃ PFHxS ˃ PFBS ˃˃ PFHpA = PFHxA = PFBA = PFPrA = 6:2 FTOH = 4:2 = FTOH = 3:1 FTOH. Similar results were observed regarding intracellular reactive oxygen species generation at both exposure times, with a tentative ranking of: PFNA ˃ PFOS ˃ PFOA ≥ PFDA ˃ PFHxS ˃ PFBS ˃ PFBA ˃ PFHpA ≥ PFHxA ˃ PFPrA ˃ 6:2 FTOH = 4:2 FTOH = 3:1 FTOH. Moreover, a concentration-dependent reactive oxygen species generation has been observed for all PFSAs and PFCAs, but not for the FTOHs. In conclusion, the carbon chain-length and functional head-group of a PFAS determine their in vitro toxicity for the two toxicological endpoints assessed in the present study. Moreover, no effects were observed for the tested FTOHs. As such, the present study established a potential structure-activity relationship that opens the possibility of developing a predictive model to help with the risk assessment of PFAS in the future.

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

Per- and polyfluoroalkyl substances (PFAS) are highly persistent, manufactured chemicals used in various manufacturing processes and found in numerous commercial products. With over 9000 compounds belonging to this chemical class, there is increasing concern regarding human exposure to these compounds due to their persistent, bioaccumulative, and toxic nature. Human exposure to PFAS may occur from a variety of exposure sources, including, air, food, indoor dust, soil, water, from the transfer of PFAS from non-stick wrappers to food, use of cosmetics, and other personal care products. This critical review presents recent research on the health-related impacts of PFAS exposure, highlighting compounds other than Perfluorooctanoic acid (PFOA) and Perfluoroctane sulfonate (PFOS) that cause adverse health effects, updates the current state of knowledge on PFAS toxicity, and, where possible, elucidates cause-and-effect relationships. Recent reviews identified that exposure to PFAS was associated with adverse health impacts on female and male fertility, metabolism in pregnancy, endocrine function including pancreatic dysfunction and risk of developing Type 2 diabetes, lipid metabolism and risk of childhood adiposity, hepatic and renal function, immune function, cardiovascular health (atherosclerosis), bone health including risk for dental cavities, osteoporosis, and vitamin D deficiency, neurological function, and risk of developing breast cancer. However, while cause-and-effect relationships for many of these outcomes were not able to be clearly elucidated, it was identified that 1) the evidence derived from both animal models and humans suggested that PFAS may exert harmful impacts on both animals and humans, however extrapolating data from animal to human studies was complicated due to differences in exposure/elimination kinetics, 2) PFAS precursor kinetics and toxicity mechanism data are still limited despite ongoing exposures, and 3) studies in humans, which provide contrasting results require further investigation of the long-term-exposed population to better evaluate the biological toxicity of chronic exposure to PFAS.

Detection methods for sub-nanogram level of emerging pollutants - Per and polyfluoroalkyl substances

Per- and polyfluoroalkyl substances (PFAS) are organofluorine compounds has been manufactured for more than five decades and used in different purposes. Among persistent organic pollutants, PFAS are toxic, bioaccumulative in humans, wildlife, and global environment. As per environmental protection agency (EPA) guidelines, the perfluorooctanoate and perfluorooctane sulfonate permissible limit was 0.07 ng/L in drinking water. When the concentration exceeds the acceptable limit, it has negative consequences for humans. In such a case, PFAS monitoring is critical, and a quick detection technique are highly needed. Health departments and regulatory agencies have interests in monitoring of PFAS presences and exposures. For the detection of PFAS, numerous highly precise and sensitive chromatographic methods are available. However, the drawbacks of analytical techniques include timely sample preparations and the lack of on-site applicability. As a result, there is an increasing demand for simple sensor systems for monitoring of PFAS in real field samples. In this review, we first describe the sample pre-treatment and analytical techniques for the detection of PFAS. Second, we broadly discussed available sensor system for the quantification of PFAS in different filed samples. Finally, future trends in PFASs sensor are also presented.

PFAS in drinking water and serum of the people of a southeast Alaska community: A pilot study

Per- and polyfluoroalkyl substances (PFAS) have become a target of rigorous scientific research due to their ubiquitous nature and adverse health effects. However, there are still gaps in knowledge about their environmental fate and health implications. More attention is needed for remote locations with source exposures. This study focuses on assessing PFAS exposure in Gustavus, a small Alaska community, located near a significant PFAS source from airport operations and fire training sites. Residential water (n = 25) and serum (n = 40) samples were collected from Gustavus residents and analyzed for 39 PFAS compounds. In addition, two water samples were collected from the previously identified PFAS source near the community. Fourteen distinct PFAS were detected in Gustavus water samples, including 6 perfluorinated carboxylic acids (PFCAs), 7 perfluorosulfonic acids (PFSAs), and 1 fluorotelomer sulfonate (FTS). ΣPFAS concentrations in residential drinking water ranged from not detected to 120 ng/L. High ΣPFAS levels were detected in two source samples collected from the Gustavus Department of Transportation (14,600 ng/L) and the Gustavus Airport (228 ng/L), confirming these two locations as a nearby major source of PFAS contamination. Seventeen PFAS were detected in serum and ΣPFAS concentrations ranged from 0.0170 to 13.1 ng/mL (median 0.0823 ng/mL). Perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) were the most abundant PFAS in both water and serum samples and comprised up to 70% of ΣPFAS concentrations in these samples. Spearman's correlation analysis revealed PFAS concentrations in water and sera were significantly and positively correlated (r = 0.495; p = 0.0192). Our results confirm a presence of a significant PFAS source near Gustavus, Alaska and suggest that contaminated drinking water from private wells contributes to the overall PFAS body burden in Gustavus residents.

Is the use of paper food contact materials treated with per- and polyfluorinated alkyl substances safe for high-temperature applications? - Migration study in real food and food simulants

Migration of per- and polyfluorinated alkyl substances (PFAS) from paper food contact materials (FCMs) can pose a consumer risk. However, risk assessment procedures typically do not consider PFAS contribution from FCMs. Moreover, migration studies are often limited to one subclass of PFAS or simplified by using food simulants (FS). To assess the risk comprehensively, migration of three PFAS subclasses (perfluorinated carboxylic acids/ sulfonic acids (PFCAs/PFSAs), polyfluoroalkyl phosphate esters (PAPs), and fluorotelomer alcohols (FTOHs)) from six FCMs were investigated to FS (50% and 20% ethanol) and food (oatmeal porridge, muffins, and tomato soup) under high-temperature conditions. Migration of PFCAs and FTOHs to all food samples was observed. Migration of PFCAs and FTOHs to 50% ethanol was significantly higher than migration to real food whilst FTOHs did not migrate into 20% ethanol. Estimated dietary PFAS exposure for children (1.06 - 5.67 ng/kgbw/day) exceeded EFSA's proposed safety threshold (0.63 ng/kgbw/day), risking consumer health.

A review on per- and polyfluorinated alkyl substances (PFASs) in microplastic and food-contact materials

Plastic, paper and cardboard are widely used as food contact materials (FCMs), due to its numerous favourable characteristics. However, they are usually coated with hazardous substances, such as per- and polyfluorinated alkyl substances (PFASs). PFASs, with its functional properties of oil- and water-repellency, can migrate from FCMs into the food and cause potential risk to human health. There are also increasing concerns about the harm that FCMs can cause to the environment. These concerns include accumulation of non-degradable plastics in the environment, generation of microplastics (MPs) and nanoplastics, and release of PFASs from FCMs. While many reviews have been conducted on PFASs in the environment, including their occurrence, fate, toxicity, biodegradation, migration in ecosystems and remediation technologies, a systematic review of PFASs in FCMs and MPs is currently lacking. In addition, our knowledge of the PFAS sorption processes on MPs is rather limited, and in particular their desorption processes. Thus, this review aims to (1) review the presence of various classes of PFASs in FCMs and their migration into food, (2) review the PFASs in MPs and summarize the sorption mechanisms, and factors that influence their sorption behaviour on MPs in the aquatic environment, and (3) identify the current research gaps and future research directions to predict the risks associated with the presence and sorption of PFASs in FCMs and MPs.

Mass-Labeled Fluorotelomer Alcohol Fragmentation Gives "False Positive" for Nonlabeled Fluorotelomer Alcohols with Implications for Consumer Product Analysis

Volatile per- and polyfluoroalkyl substances (PFAS) are detected in various consumer goods, raising concerns over environmental fate and human exposure. Volatile PFAS are commonly analyzed by gas chromatography-chemical ionization-mass spectrometry. Mass-labeled standards are used for quantitative analysis of volatile PFAS and to ensure quality control. However, mass-labeled fluorotelomer alcohol (FTOH) analyzed in positive chemical ionization produces signals corresponding to nonlabeled (native) FTOH ions, resulting in false positives. This observation was attributed to deuterium or hydrogen abstraction of mass-labeled standards. Deuterium abstraction of deuterated standards, including d₄-4:2 FTOH, ¹³C₂-d₂-6:2 FTOH, ¹³C₂-d₂-10:2 FTOH, and hydrogen abstraction of ¹³C-labeled standard ¹³C₂-8:2 FTOH are ionization artifacts that yielded responses for native FTOH m/z values. False positives for native (nonlabeled) FTOHs caused by the introduction of a mass-labeled surrogate can be controlled by blank subtracting or decreasing mass-labeled standard concentrations. Alternatively, different mass-labeled standards can also be used in sample analysis.

The impact of legacy and novel perfluoroalkyl substances on human cytochrome P450: An in vitro study on the inhibitory potential and underlying mechanisms

Per- and polyfluoroalkyl substances (PFASs) are a group of synthetic compounds with a wide range of industrial applications. PFOA and PFOS have been the most extensively studied and have been associated with hepatotoxicity. Recently, the interaction with cytochrome P450 (CYP) has been proposed as a potential key molecular event leading to PFAS-induced hepatotoxicity. In the present study, we aimed to determine a structure-activity relationship between thirteen PFASs and their inhibitory potential on the activities of four CYPs (CYP2E1, CYP2D6, CYP3A4 and CYP2C19). The influence of PFASs (5- 3200 µM) on CYP enzyme activities was measured using the Vivid® P450 metabolism assays. Using the same assays, Michaelis-Menten saturation curves were determined to explore the type of PFAS-induced CYP inhibition. Most PFASs were capable of inhibiting activity of the tested CYPs, as shown by their IC50 values. CYP2E1 is particularly inhibited by 3:1 FTOH, PFOA, and PFOS, whereas CYP2D6 is inhibited by PFHxS, PFHpA, PFOA, PFOS, PFNA, and PFDA. Additionally, CYP3A4 is most strongly inhibited by PFHxS, PFOA, PFOS, PFNA, and PFDA. Finally, CYP2C19 is inhibited by PFBS, PFHxS, PFHpA, PFOA, PFOS, PFNA, and PFDA. Interestingly, PFHxA and PFHxS induced an increase in CYP2E1 activity, whereas 4:2 FTOH strongly induced CYP2D6 activity. The mechanism of inhibition of CYPs by PFASs differed per CYP isoenzyme. CYP3A4 was competitively inhibited by PFBS, PFHxS, PFOS, PFNA and PFDA and non-competitively by PFOA. Additionally, CYP2C19 was competitively inhibited by PFHxA, PFOS and PFNA, whereas PFBS and PFHxS induced a mixed inhibition. Inhibition of CYP2C19 by PFHpA was atypical with an increased Vmax and a decreased Km. Finally, PFHxS competitively inhibited CYP2D6, whereas PFBS, PFOA, PFOS, PFDA and PFNA induced an atypical inhibition. Our results show that CYP inhibition by PFASs appears to be structure-dependent as well as CYP dependent. Inhibition of CYP2D6, CYP2C19 and CYP3A4 increased with increasing chain-lengths between six and nine carbons. The PFTOHs were only able to inhibit CYP2E1 and did not affect any of the other CYPS. Some PFASs remarkably induced the enzyme activity of CYPs. These results indicate that in addition to PFOA and PFOS, multiple novel PFASs may alter drug metabolism by the interference with CYPs.

Characterization of Per- and Polyfluorinated Alkyl Substances Present in Commercial Anti-fog Products and Their In Vitro Adipogenic Activity

Anti-fog sprays and solutions are used on eyeglasses to minimize the condensation of water vapor, particularly while wearing a mask. Given their water-repellent properties, we sought to characterize per- and polyfluorinated alkyl substance (PFAS) compounds in four anti-fog spray products, five anti-fog cloth products, and two commercial fluorosurfactant formulations suspected to be used in preparing anti-fog products. Fluorotelomer alcohols (FTOHs) and fluorotelomer ethoxylates (FTEOs) were detected in all products and formulations. While 6:2 FTOH and the 6:2 FTEO polymeric series were predominant, one anti-fog cloth and one formulation contained 8:2, 10:2, 12:2, 14:2, and 16:2 FTOH and FTEO polymeric series. PFAS concentrations varied in samples and were detected at levels up to 25,000 μg/mL in anti-fog sprays and 185,000 μg (g cloth)^-1 in anti-fog cloth products. The total organic fluorine (TOF) measurements of anti-fog products ranged from 190 to 20,700 μg/mL in sprays and 44,200 to 131,500 μg (g cloth)^-1 in cloths. Quantified FTOHs and FTEOs accounted for 1-99% of TOF mass. In addition, all four anti-fog sprays and both commercial formulations exhibited significant cytotoxicity and adipogenic activity (either triglyceride accumulation and/or pre-adipocyte proliferation) in murine 3T3-L1 cells. Results suggest that FTEOs are a significant contributor to the adipogenic activity exhibited by the anti-fog sprays. Altogether, these results suggest that FTEOs are present in commercial products at toxicologically relevant levels, and more research is needed to fully understand the health risks from using these PFAS-containing products.

Prevalence and Implications of Per- and Polyfluoroalkyl Substances (PFAS) in Settled Dust

PURPOSE OF REVIEW

Per- and polyfluoroalkyl substances (PFAS) are a family of more than 7,000 fluorinated compounds. The carbon-fluorine bond of PFAS provides desirable hydrophobic and oleophobic properties and stability that has led to widespread usage in consumer products and industrial applications. The strength of the carbon-fluorine bond also prevents appreciable degradation once released into the environment. Consequently, various household products can release volatile and nonvolatile PFAS into the indoor environment that often concentrate in dust. We discuss the diversity of PFAS in settled dust, emission sources of these chemicals, changes in PFAS profiles in dust over the past century, and the implications for human health.

RECENT FINDINGS

Sources of PFAS found in dust include building materials and furnishings and consumer products used in typical indoor spaces. Daycares and workplaces are emphasized as locations with widespread exposure due to the presence of treated carpeting and industrial-strength cleaners. Comparison and interpretation of findings across studies are complicated by the different ways in which PFAS are screened across studies. We further discuss recent developments in non-targeted software for the comprehensive annotation of PFAS in indoor dust and emphasize the need for comprehensive and harmonized analytical workflows. We highlight the detection and diversity of PFAS in settled dust collected from various indoor spaces, including locations with vulnerable subpopulations. There are opportunities for future research to leverage settled dust as a sentinel environmental matrix to evaluate the link between inhalation and ingestion routes of PFAS exposure to adverse health.

Occurrence, distribution, and risk assessment of perfluoroalkyl acids in drinking water sources from the lower Yangtze River

The occurrence, spatial distribution, potential sources, and risk assessment of 14 perfluoroalkyl acids (PFAAs), including 11 perfluoroalkyl carboxylic acids and 3 perfluoroalkyl sulfonates acids, were investigated in 21 drinking water sources from the lower Yangtze River in November 2019. The total PFAAs (∑PFAAs) concentrations ranged from 39.3 to 220.3 ng/L, and perfluorooctanoic acid and perfluorooctanesulfonate were predominant with average concentrations of 19.4 and 15.4 ng/L, respectively. The higher ∑PFAAs concentrations in the southern shore and downstream could be attributed to industrial development and surface runoff/tide currents, respectively. Principal component analysis-multiple linear regression revealed that the primary sources of PFAAs were fluororesin coatings/metal plating, surface runoff/textile, effluent discharge/food packaging, and leather/fabrics. Human intake risks of PFAAs were assessed by target hazard quotient (THQ), which showed that human health risks of PFAAs decreased with increasing age, excluding 13-17 years age group. Moreover, the total exposure risks of PFOA/PFOS in all sampling sites to people aged over 18 years calculated based on contribution from drinking water were noted to be at safe level. The results obtained were helpful for improving our understanding of human health risks of PFAAs, and expanding our knowledge on PFAAs in drinking water.

Per/polyfluoroalkyl substances production, applications and environmental impacts

The per/polyfluoroalkyl substances (PFAS) are growing contaminants which are extremely difficult to get degraded naturally. PFAS have been produced for nearly a century using electrochemical flourination and more relomerization processes. High chemical resistance, hydrophobicity, lipophobicity, heat resistace, extremly low friction coefficient make this class of chemicals invaluable for many applications. These same properties useful unfortunately make them 'forever chemicals' once released into the envrironment. This review focuses on the production and applications of PFAs, determining the concentration of PFAs in environmental and biological matrices and their efficient degradation. Various methods of detection of PFAS have been developed but insitu methods of detction are still in the early stages of development. Current chemical and biological remediation technologies are expensive/not effective and thus new remediation technolgies must be developed. It is imperative to focus on methods for detection of the short chain PFAS with their projected increased use.

Presence of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in Food Contact Materials (FCM) and Its Migration to Food

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are synthetic chemical compounds widely used in different industry fields including food contact materials (FCM), providing resistance to fat and humidity, and non-stick properties. PFAS enter into the food chain directly from the intake of contaminated food or indirectly from the migration of the FCM into the food. This exposure published in different research highlights a public health concern. Therefore, it is necessary to perform analysis of the content of different FCM and evaluate the migration from the FCM under normal conditions of use and storage. This bibliographical review proves that different perfluoroalkyl and polyfluoroalkyl compounds are detected in fast food packaging, microwave popcorn bags, and frying pans, among others. Furthermore, it shows the conditions or factors that favor the migration of the PFAS from the FCM into the food.

Investigating Molecular Mechanisms of Immunotoxicity and the Utility of ToxCast for Immunotoxicity Screening of Chemicals Added to Food

The development of high-throughput screening methodologies may decrease the need for laboratory animals for toxicity testing. Here, we investigate the potential of assessing immunotoxicity with high-throughput screening data from the U.S. Environmental Protection Agency ToxCast program. As case studies, we analyzed the most common chemicals added to food as well as per- and polyfluoroalkyl substances (PFAS) shown to migrate to food from packaging materials or processing equipment. The antioxidant preservative tert-butylhydroquinone (TBHQ) showed activity both in ToxCast assays and in classical immunological assays, suggesting that it may affect the immune response in people. From the PFAS group, we identified eight substances that can migrate from food contact materials and have ToxCast data. In epidemiological and toxicological studies, PFAS suppress the immune system and decrease the response to vaccination. However, most PFAS show weak or no activity in immune-related ToxCast assays. This lack of concordance between toxicological and high-throughput data for common PFAS indicates the current limitations of in vitro screening for analyzing immunotoxicity. High-throughput in vitro assays show promise for providing mechanistic data relevant for immune risk assessment. In contrast, the lack of immune-specific activity in the existing high-throughput assays cannot validate the safety of a chemical for the immune system.

Remediation of poly- and perfluoroalkyl substances (PFAS) contaminated soils - To mobilize or to immobilize or to degrade?

Poly- and perfluoroalkyl substances (PFASs) are synthetic chemicals, which are introduced to the environment through anthropogenic activities. Aqueous film forming foam used in firefighting, wastewater effluent, landfill leachate, and biosolids are major sources of PFAS input to soil and groundwater. Remediation of PFAS contaminated solid and aqueous media is challenging, which is attributed to the chemical and thermal stability of PFAS and the complexity of PFAS mixtures. In this review, remediation of PFAS contaminated soils through manipulation of their bioavailability and destruction is presented. While the mobilizing amendments (e.g., surfactants) enhance the mobility and bioavailability of PFAS, the immobilizing amendments (e.g., activated carbon) decrease their bioavailability and mobility. Mobilizing amendments can be applied to facilitate the removal of PFAS though soil washing, phytoremediation, and complete destruction through thermal and chemical redox reactions. Immobilizing amendments are likely to reduce the transfer of PFAS to food chain through plant and biota (e.g., earthworm) uptake, and leaching to potable water sources. Future studies should focus on quantifying the potential leaching of the mobilized PFAS in the absence of removal by plant and biota uptake or soil washing, and regular monitoring of the long-term stability of the immobilized PFAS.

Fluorotelomer Alcohols' Toxicology Correlates with Oxidative Stress and Metabolism

Fluorotelomer alcohols (FTOHs) are widely used as industrial raw materials due to their unique hydrophobic and oleophobic properties. However, because of accidental exposure to products containing FTOHs or with the widespread use of FTOHs, they tend to contaminate the water and the soil. There are reports demonstrating that FTOHs can cause various harmful effects in animals and humans (for example, neurotoxicity, hepatotoxicity, nephrotoxicity, immunotoxicity, endocrine-disrupting activity, and developmental and reproductive toxicities). Oxidative stress is related to a variety of toxic effects induced by FTOHs. To date, few reviews have addressed the relationship between the toxicity of FTOHs and oxidative stress. This article summarises research demonstrating that the toxicity induced by FTOHs correlates with oxidative stress and metabolism. Furthermore, during the metabolic process of FTOHs, a number of cytochrome P450 enzymes (CYP450) are involved and many metabolites are produced by these enzymes, which can induce oxidative stress. This is also reviewed.