Variations of the Level, Profile, and Distribution of PFAS around POSF Manufacturing Facilities in China: An Overlooked Source of PFCA

Downward migration of per- and polyfluoroalkyl substances (PFAS) in lake sediments: Reconsideration of temporal trend analysis

Using sediment cores to reconstruct the contamination history of per- and polyfluoroalkyl substances (PFAS) is essential for chemical management but poses challenge. Herein, sediment cores, as well as surface water and sediments were taken from two Chinese lakes to investigate the vertical distribution and migration of PFAS. Wind wave, properties of sediment and water, and chemical characters of PFAS were examined to clarify the main factors influencing PFAS migration. Total PFAS concentrations in sediment cores ranged from 0.12 to 5.28 ng g-1 dry weight (dw) in Dianchi Lake and from 0.19 to 2.51 ng g-1 dw in Taihu Lake, respectively. Strong hydrodynamic disturbance (wind-wave erosion depth up to 30 cm) in Taihu Lake resulted in consistent PFAS levels and profiles throughout the sediment core, limiting its use for retrospective analysis. In Dianchi Lake, an increasing trend of total organic carbon-normalized PFAS indicated their persistent emission in China over the past decades. Perfluorooctane sulfonic acid increased markedly from early 2000s; temporal trend in composition for perfluorocarboxylates coincided with the global production transition. Finally, we proposed a three-step conceptual framework, including lake selection, key time point assessment, and contamination history reconstruction, to further improve the reliability of PFAS retrospective analysis in lake.

A clustering approach based on high-resolution ecological vulnerability index reveals spatial patterns of per- and polyfluoroalkyl substances pollution in lakes on the Tibetan Plateau

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants (POPs) with toxicity, chemical stability, and long-range transport potential. The transport and accumulation mechanisms of PFAS in specific or typical lakes have been reported. In the wake of global PFAS pollution, it is more important to unravel the distribution patterns of PFAS across larger-scale, multi-lake systems. However, traditional lake classification methods are often overly simplistic and inflexible to adapt to large lake systems with complex ecological characteristics. Here, an improved ecological vulnerability index (EVI) was introduced and applied for the first time to classify lakes in a regional, multi-lake study of PFAS pollution. We evaluated the effectiveness of EVI that integrated multi-dimensional environmental factors in revealing PFAS distribution in 12 lakes on the Tibetan Plateau. The results showed that the composition, concentration, and diversity of PFAS in water and sediment samples significantly differed between high-vulnerability lakes (HVL) and low-vulnerability lakes (LVL) clustered by EVI. The linear regression of PFAS concentration and diversity on EVI was most pronounced at the 1-km buffer zone scale compared to larger scales. EVI was strongly associated with PFAS concentration and diversity in HVL dominated by natural factors, and these associations were weakened in LVL with prevalent human interference. Our findings indicate the greater potential of EVI to predict the spatial patterns of PFAS in lakes at smaller scales and across regions with comparable dominance of natural factors. The proposed clustering approach is adaptable, as the indicators and weights in the EVI system can be adjusted based on regional ecological characteristics. This study provides a tool for unveiling the distribution patterns of PFAS and their driving mechanisms in complex lake environments.

A Critical Review of Populations with Occupational Exposure to Per- and Polyfluoroalkyl Substances: External Exposome, Internal Exposure Levels, and Health Effects

The relationship between per- and polyfluoroalkyl substances (PFAS) exposure and human health has received widespread attention. This review focuses on the key distinctions in PFAS exposure between the occupational population and the general population from different countries. A systematic summary is made from the external exposure environment, exposure pathways, internal exposure levels, and health effects of the occupational population. The manufacturing, use, and disposal processes of PFAS increase their concentration levels in the ambient environment, leading to significantly higher concentrations than background areas. Different PFAS exposure pathways may lead to different molecular initiating events and health outcomes in the occupational population and the general population. Moreover, the PFAS exposure levels of the occupational population are nearly one hundred times higher than those of the general population. Mixed exposure to more unknown PFAS is another important feature of the occupational population. Although occupational exposure to PFAS is not associated with mortality, PFAS exposure can significantly disrupt metabolic pathways and cause adverse effects on the liver, kidney, and lipid homeostasis. Therefore, more stringent occupational protections for the PFAS occupational population are necessary to reduce their health risks.

Interactive effects of soil dissolved organic matter (DOM) and Per- and polyfluoroalkyl substances on contaminated soil site: DOM molecular-level perspective

Dissolved organic matter (DOM), as the most active soil component, plays a crucial role in regulating the transport of contaminants. Per- and polyfluoroalkyl substances (PFAS) have been found to be widespread contaminants in the soil environment, and their migration would be also affected by DOM. Herein, the surface and subsurface soil samples collected from two PFAS manufacturing factories were studied for the variation characteristics of DOM under PFAS contamination, and the interaction between DOM and PFAS in soil was further explored. The results showed that PFAS contamination significantly reduced the richness of surface soil DOM. For the specific DOM components, the potential transformation of DOM in subsurface soil indicates that the presence of PFAS promotes the transformation of other DOM components to PA compounds. Moreover, a strong positive relationship was observed between the concentration of most perfluoroalkyl sulfonic acids (PFSAs) and the average unsaturation (DBE) and aromaticity index (AImod) of DOM, while no such relationship for perfluoroalkyl carboxylic acids (PFCAs), suggesting DBE and AImod may be a potential contributor influencing the distribution and transport of PFSAs. These findings highlight the interaction between DOM and the PFAS in the soil environment, which may enhance our understanding of the release and fate of PFAS in the soil environment.

Co-occurrence of PFASs, TPHs, and BTEX in subsurface soils: Impacts on native microbial communities and implications for bioremediation

This study investigates the co-occurrence of per- and polyfluoroalkyl substances (PFASs), petroleum hydrocarbons (TPHs) and benzene, toluene, ethylbenzene, and xylene (BTEX) and their effects on the indigenous microbial communities in soils at a contaminated site with a history of petroleum refinery operations. PFASs concentrations were in the range of 5.65-6.73 ng/g, and fluorooctane sulfonate (PFOS) and perfluorobutane sulfonic acid (PFBS) were the dominating compounds. No significant difference was observed in the PFASs concentration profiles between the site and background locations, indicating that PFASs detected in the soil samples were mainly contributed from non-point sources, due to the long-distance transport of PFASs in the region. The concentrations of TPHs and BTEX ranged from 227 to 72,360 mg/kg and 0.06-2109.77 mg/kg, respectively, mainly contributed by the historical refinery activities. The presence of PFASs, TPHs, and BTEX significantly impacted soil microbial community diversity and abundance, altering microbial compositions and enriching bacteria with higher resistance or metabolic capabilities against contamination. Strong correlations were observed between TPHs and its degraders such as Pseudomonas, Azoarcus, and Polaromonas. Significant positive relationship between PFASs and Trichlorobacter implied the potential defluorination capabilities of Trichlorobacter, warranting further investigation. Moreover, the higher energy metabolism including carbon, nitrogen and sulfur metabolisms and higher abundance of metabolic enzymes for alkane, cyclohexane and toluene in the refinery site revealed the potential occurrence of natural biodegradation of contaminants with indigenous microbial community. These findings highlight the complexity of sites contaminated with a mixture of traditional and emerging contaminants, providing valuable insights into the potential for biodegradation of mixed contaminants and underscoring the need for integrated approaches in environmental remediation strategies. This study contributes to understanding the ecological impacts of co-occurring contaminants and emphasizes the importance of considering multiple contaminant types in environmental risk assessments and remediation efforts.

Dynamic estimation of the soil environmental carrying capacity for Benzo(a)pyrene in an industrial city, China: Insight from both duration and rate of regional emission

An in-depth investigation of the maximum environmental load is crucial for soil security and pollution prevention. This research focused on soil environmental carrying capacity (SECC) for different risk receptors in a Chinese industrial city. By determining risk threshold for various land use types, we integrated mass balance and iterative models to capture dynamic net input fluxes with spatial heterogeneity. This enabled quantitative characterization of Benzo(a)pyrene (BaP) SECC through top-down and bottom-up approaches (corresponding to duration (D) and rate of regional emission, respectively). The thresholds were in the order of agricultural land < residential land < forest < industrial land < park. The top-down analysis showed D increased ∼1.5x with a 5% input flux decline until 2031. The bottom-up analysis suggested industrial emissions decreased by approximately 10% as the pollution control period was extended from 20 to 50 years. Both methods showed that at maximum background values (C0), D was ∼4x and the industrial emission rate was ∼10% higher than at minimum C0. SECC values near industrial areas significantly decreased, even reaching negative values, signifying complete carrying capacity loss. This study provided an approach to the dynamics of SECC under diverse scenarios, aiding informed decision-making for sustainable land management.

Legacy and Novel Per- and Polyfluoroalkyl Substances in Surface Soils across China: Source Tracking and Main Drivers for the Spatial Variation

China aims to actively control the contamination of globally concerning per- and polyfluoroalkyl substances (PFASs). Evaluation of the current situation can provide a critical reference point for tracking the effectiveness of ongoing progress. Herein, we present the first comprehensive assessment of the spatial variations of 20 legacy and 54 novel PFASs in Chinese background soils in 2021. Novel PFASs were extensively detected in 98.4% of the samples, with 21 species being first reported, which greatly facilitated the appointment of diverse emission sources that aligned with local industrial structures. However, legacy PFASs still dominated the ∑74PFAS profile (median 0.51 ng/g, 0.050-8.33 ng/g). The spatial heterogeneity of soil PFASs was positively driven by economic development and atmospheric deposition, enabling the establishment of predictive models to project the national distribution and temporal trends. Elevated PFAS levels were predominantly distributed in the more industrialized eastern and southern regions, as well as other coastal areas with greater precipitation. ∑74PFAS in surface soils was estimated to increase by 12.9 pg/(g year) over 2002-2021, which would continue alongside economic growth, albeit with greater contributions from novel alternatives. Our work provides comprehensive baseline and predictive data to inform policies toward PFAS control in China.

A combinational threat of micro- and nano-plastics (MNPs) as potential emerging vectors for per- and polyfluoroalkyl substances (PFAS) to human health

Micro- and nano-plastics (MNPs) and per- and polyfluoroalkyl substances (PFAS) are prevalent in ecosystems due to their exceptional properties and widespread use, profoundly affecting both human health and ecosystem. Upon entering the environment, MNPs and PFAS undergo various transformations, such as weathering, transport, and accumulation, potentially altering their characteristics and structural dynamics. Their interactions, governed by factors like hydrogen bonding, hydrophobic interactions, Van der Waals forces, electrostatic attractions, and environmental conditions, can amplify or mitigate their toxicity toward human health within ecological conditions. Several studies demonstrate the in vivo effects of PFAS and MNPs, encompassing growth and reproductive impairments, oxidative stress, neurotoxicity, apoptosis, DNA damage, genotoxicity, immunological responses, behavioral changes, modifications in gut microbiota, and histopathological alterations. Moreover, in vitro investigations highlight impacts on cellular uptake, affecting survival, proliferation, membrane integrity, reactive oxygen species (ROS) generation, and antioxidant responses. This review combines knowledge on the co-existence and adsorption of PFAS and MNPs in the environment, defining their combined in vivo and in vitro impacts. It provides evidence of potential human health implications. While significant research originates from China, Europe, and the USA, studies from other regions are limited. Only freshwater and marine organisms and their impacts are extensively studied in comparison to terrestrial organisms and humans. Nonetheless, detailed investigations are lacking regarding their fate, combined environmental exposure, mode of action, and implications in human health studies. Ongoing research is imperative to comprehensively understand environmental exposures and interaction mechanisms, addressing the need to elucidate these aspects thoroughly.

Co-emissions of fluoride ion, fluorinated greenhouse gases, and per- and polyfluoroalkyl substances (PFAS) from different fluorochemical production processes

Fluorochemical industry is an emerging industry leading to environmental emissions of fluoride ion, fluorinated greenhouse gases (GHGs) and per- and polyfluoroalkyl substances (PFASs) globally. Chlorofluorocarbon (CFCs) and hydrochlorofluorocarbon (HCFCs) are the primary causes of ozone layer depletion, and together with hydrofluorocarbons (HFCs), they contribute to global climate warming. PFAS are emerging persistent organic pollutants, comprising thousands of materials including perfluoroalkyl acids (PFAAs), perfluoroalkane sulfonamides (FASAs), and fluoropolymers.As the implementation of the Montreal Protocol and the Stockholm Convention makes progress, fluorochemical industry is searching for alternatives like HFCs, perfluoroalkyl ether carboxylic acids (PFECAs) and etc. Even though studies on chemical processes and environmental influences of the fluorochemical industry are plentiful, research on emissions of fluorine chemicals from different fluorochemical industry is still scarce. In this study, we conducted on-site sampling to analyze the distribution of fluorine chemicals in the surrounding environment of the fluorochemical industrial sites. The sampling sites represent different stages of fluorochemical industry production, including fluorite mining, synthesis of fluorochemical raw materials like fluorocarbons, and fine fluorine product processing which is mostly PFAS. Results show that at the fluorite mining stage, concurrent emissions of fluoride ion and CFC-12 contribute to the primary environmental issue. Perfluorooctanoic acid (PFOA) and some short-chain PFASs like perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), and perfluorobutanesulfonic acid (PFBS) are the main pollutants from fluocarbons production, accompanied by emissions of fluorinated GHGs such as HFC-32, and HCFC-22. At the fine fluorine product synthesis stage where produces fluoropolymers, perfluoropolyethers and fluorinated surfactants, PFAS especially for emerging alternatives PFECAs like hexafluoropropylene oxide dimer acid (HFPODA) and Perfluoro-4-oxapentanoic acid (PF4OPeA), as well as fluorinated GHGs like HFC-23 and HFC-227ea, require increasing attention.

Which pollutants and sources should be prioritized for control in multi-pollutants complex contaminated areas?

Risk assessment and source identification of multi-pollutants are essential for accurate control of soil contamination. However, complexity in pollutant properties and diversity in source types raise challenges to the target. Therefore, this study constructed a hierarchical ecological risk quantification method combined with risk ranking, risk of single pollutant using potential affected fraction (PAF), and joint risk of multi-pollutants employing msPAF. Taking regional contamination in South China as a case, the risk ranking was determined, while single and joint effects showed msPAF reaching 79.4 %, with risk as heavy metals (HMs) > per- and polyfluoroalkyl substances (PFASs) > polycyclic aromatic hydrocarbons (PAHs). Meanwhile, an integrated source apportionment method was established from three layers by principal component analysis to classify source types, multiple linear regression of distance to identify key sources, and positive matrix factorization to track omitted sources. Consequently, key sources were captured, with 80.8 %-93.2 % contribution of farmland and electroplating to three main HMs, 52.2 %-69.4 % contribution of roads to three main PAHs, and 71.1 %-73.2 % contribution of electroplating to two main PFASs. Further, omitted sources were tracked with contribution of 31.2 %-84.1 % to eight pollutants. The established methods can identify control targets, including high-risk pollutants and their key sources.

Natural mineral and industrial solid waste-based adsorbent for perfluorooctanoic acid and perfluorooctane sulfonate removal from surface water: Advances and prospects

PER: and polyfluorinated alkyl substances, especially perfluorooctanoic acid and perfluorooctane sulfonic acid (PFOX), have attracted considerable attention lately because of their widespread occurrence in aquatic environment and potential biological toxicity to animals and human beings. The development of economical, efficient, and engineerable adsorbents for removing PFOX in water has become one of the research focuses. This review summarized the recent progress on natural mineral and industrial solid based adsorbent (NM&ISW-A) and removal mechanisms concerning PFOX onto NM&ISW-A, as well as proposed the current challenges and future perspectives of using NM&ISW-A for PFOX removal in water. Kaolinite and montmorillonite are usually used as model clay minerals for PFOX removal, and have been proved to adsorb PFOX by ligand exchange and electrostatic attraction. Fe-based minerals, such as goethite, magnetite, and hematite, have better PFOX adsorption capacity than clay minerals. The adsorbent prepared from industrial solid waste by high temperature roasting has great potential application prospects. Fabricating nanomaterials, amination modification, surfactant modification, fluorination modification, developing versatile composites, and designing special porous structure are beneficial to improve the adsorption performance of PFOX onto NM&ISW-A by enhancing the specific surface area, positive charge, and hydrophobicity. Electrostatic interaction, hydrophobic interaction, hydrogen bond, ligand and ion exchange, and self-aggregation (formation of micelle or hemimicelle) are the main adsorption mechanisms of PFOX by NM&ISW-A. Among them, electrostatic and hydrophobic interactions play a considerable role in the removal of PFOX by NM&ISW-A. Therefore, NM&ISW-A with electrostatic functionalities and considerable hydrophobic segments enables rapid, efficient, and high-capacity removal of PFOX. The future directions of NM&ISW-A for PFOX removal include the preparation and regeneration of engineerable NM&ISW-A, the development of coupling technology for PFOX removal based on NM&ISW-A, the in-depth research on adsorption mechanism of PFOX by NM&ISW-A, as well as the development of NM&ISW-A for PFOX alternatives removal. This review paper would be helpful the comprehensive understanding of NM&ISW-A potential for PFOX removal and the PFOX removal mechanisms, and identifies the gaps for future research and development.

Spatial distribution, source, and fate of per- and polyfluoroalkyl substances in the surrounding environment of closed and converted fluorochemical factories in Fujian, China

Following the closure of perfluorooctanesulfonic acid (PFOS) production to comply with the Stockholm Convention regulations or restrictions, manufacturers have shifted to developing short-chain alternatives like perfluorobutane sulfonic acid (PFBS). However, limited research has been conducted to evaluate the impact of this transition on the surrounding environment. This study focused on the spatial distribution, source, and fate of 18 per- and polyfluoroalkyl substances (PFAS) in the surrounding environment of the closure and transformation of two PFAS manufacturing plants in Fujian, China. The total concentrations of PFAS in surface water, sediment, and fish were within the range of 48.9-72,400 ng/L, 0.930-57.6 ng/g dw, and 3.33-1245 ng/g dw, respectively. The predominant compounds were PFBS, PFOS, and perfluorooctanoic acid (PFOA) among the three matrices. Principal component analysis highlighted significant differences in PFAS profiles across different regions of the Futun River, suggesting diverse sources of PFAS. Source apportionment indicated that despite being closed or converted for almost three years, the two factories still significantly impacted the surrounding environment. The shutdown factory mainly released PFAS characterized by perfluoroalkyl sulfonic acids. In contrast, the PFAS were released from conversion plant with the fingerprint being PFBS and perfluoroalkyl carboxylic acids. The conversion of the factories has resulted in the coexistence of long-chain and short-chain PFAS, which has complicated the composition of PFAS in the environment. As sewage treatment plant could not effectively remove PFBS and perfluorobutanoic acid (PFBA) in wastewater, and due to their strong migration ability, these chemicals had a wider impact range, increasing the difficulty of environmental restoration and management. Risk assessment showed that PFAS downstream of the two factories posed high or moderate ecological risks. Specifically, PFBS, PFOS, and PFOA displayed the highest risk quotients and should be paid further attention.

Analysis of Legacy and Novel Neutral Per- and Polyfluoroalkyl Substances in Soils from an Industrial Manufacturing Facility

Per- and polyfluoroalkyl substances (PFASs) have been detected in an array of environmental media due to their ubiquitous use in industrial and consumer products as well as potential release from fluorochemical manufacturing facilities. During their manufacture, many fluorotelomer (FT) facilities rely on neutral intermediates in polymer production including the FT-alcohols (FTOHs). These PFAS are known to transform to the terminal acids (perfluoro carboxylic acids; PFCAs) at rates that vary with environmental conditions. In the current study on soils from a FT facility, we employed gas chromatography coupled with conventional- and high-resolution mass spectrometry (GC-MS and GC-HRMS) to investigate the profile of these precursor compounds, the intermediary secondary alcohols (sFTOHs), FT-acrylates (FTAcr), and FT-acetates (FTAce) in soils around the former FT-production facility. Of these precursors, the general trend in detection intensity was [FTOHs] > [sFTOHs] > [FTAcrs], while for the FTOHs, homologue intensities generally were [12:2 FTOH] > [14:2 FTOH] > [16:2 FTOH] > [10:2 FTOH] > [18:2 FTOH] > [20:2 FTOH] > [8:2 FTOH] ∼ [6:2 FTOH]. The corresponding terminal acids were also detected in all soil samples and positively correlated with the precursor concentrations. GC-HRMS confirmed the presence of industrial manufacturing byproducts such as FT-ethers and FT-esters and aided in the tentative identification of previously unreported dimers and other compounds. The application of GC-HRMS to the measurement and identification of precursor PFAS is in its infancy, but the methodologies described here will help refine its use in tentatively identifying these compounds in the environment.

Nontarget Discovery of Per- and Polyfluoroalkyl Sulfonyl Halides in Soils by Integration of Derivatization and Specific Fragment-Based Liquid Chromatography-High Resolution Mass Spectrometry Screening

Though long recognized as synthetic precursors to other poly- and perfluoroalkyl substances (PFASs), most poly- and perfluoroalkyl sulfonyl halides (PASXs) cannot be directly measured and have generally received minimal attention. Inspired by the redox reaction between sulfonyl halide groups and p-toluenethiol in organic chemistry, we developed a novel nontarget analysis strategy for PASXs by intergrating derivatization and specific fragment-based liquid chromatography-high resolution mass spectrometry screening for m/z 82.961 [SO2F-] and m/z 95.934 [S2O2-]. By using this strategy, we discovered 11 PASXs, namely, perfluoroalkyl sulfonyl fluorides (5), polyfluoroalkyl sulfonyl fluorides (2), unsaturated perfluoroalkyl sulfonyl fluoride (1), and perfluoroalkyl sulfonyl chlorides (3) in soil samples collected from an abandoned fluorochemical manufacturing park. These average ∑PASXs concentrations were 1120 μg kg-1 (range: 9.7-9860 μg kg-1), which were very likely to be the key intermediates and undesired byproducts of electrochemical fluorination processes. Spatial variation in the mass ratio of ∑PASXs to ∑PFSAs (range: 0.7-795%) also indicates their different transportation pathways. More importantly, the decline of PASXs and increase of perfluoroalkyl sulfonates (when compared to a prior study at this site) suggest the continued hydrolysis of PASXs and the relatively fast environmental transformation rates in the abandoned fluorochemical park soils. Overall, these findings demonstrated the utility of a novel nontarget analysis strategy, which may change most PASXs from inferred precursors to measured intermediates and further could be adapted for structures, distribution, and transformation studies of PFASXs in other matrices.

Spatial distribution, compositional characteristics, and source apportionment of legacy and novel per- and polyfluoroalkyl substances in farmland soil: A nationwide study in mainland China

China, as one of the largest global producers and consumers of per- and poly-fluoroalkyl substances (PFASs), faces concerning levels of PFAS pollution in soil. However, knowledge of their occurrence in agricultural soils of China on the national scale remains unknown. Herein, the first nationwide survey was done by collecting 352 soil samples from 31 provinces in mainland China. The results indicated that the Σ24PFASs concentrations were 74.3 - 24880.0 pg/g, with mean concentrations of PFASs in decreasing order of legacy PFASs > emerging PFASs > PFAS precursors (640.2 pg/g, 340.7 pg/g, and 154.9 pg/g, respectively). The concentrations in coastal eastern China were distinctly higher than those in inland regions. Tianjin was the most severely PFASs-contaminated province because of rapid urban industrialization. This study further compared the PFAS content in monoculture and multiple cropping farmland soils, finding the concentrations of PFASs were high in soils planted with vegetable and fruit monocultures. Moreover, a positive matrix factorization (PMF) model was employed to identify different sources of PFASs. Fluoropolymer industries and aqueous film-forming foams were the primary contributors. The contributions from different emission sources varied across the seven geographical regions. This study provides new baseline data for prevention and control policies for reducing pollution.

Crop Contamination and Human Exposure to Per- and Polyfluoroalkyl Substances around a Fluorochemical Industrial Park in China

Due to their significant environmental impact, there has been a gradual restriction of the production and utilization of legacy per- and polyfluoroalkyl substances (PFAS), leading to continuous development and adoption of novel alternatives. To effectively identify the potential environmental risks from crop consumption, the levels of 25 PFAS, including fourteen perfluoroalkyl acids (PFAAs), two precursor substances and nine novel alternatives, in agricultural soils and edible parts of various crops around a fluoride industrial park (FIP) in Changshu city, China, were measured. The concentration of ΣPFAS in the edible parts of all crops ranged from 11.64 to 299.5 ng/g, with perfluorobutanoic acid (PFBA) being the dominant compound, accounting for an average of 71% of ΣPFAS. The precursor substance, N-methylperfluoro-octanesulfonamidoacetic acid (N-MeFOSAA), was detected in all crop samples. Different types of crops showed distinguishing accumulation profiles for the PFAS. Solanaceae and leafy vegetables showed higher levels of PFAS contamination, with the highest ΣPFAS concentrations reaching 190.91 and 175.29 ng/g, respectively. The highest ΣAlternative was detected in leafy vegetables at 15.21 ng/g. The levels of human exposure to PFAS through crop consumption for various aged groups were also evaluated. The maximum exposure to PFOA for urban toddlers reached 109.8% of the standard value set by the European Food Safety Authority (EFSA). In addition, short-chained PFAAs and novel alternatives may pose potential risks to human health via crop consumption.

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.

Distribution of select per- and polyfluoroalkyl substances at a chemical manufacturing plant

Per- and polyfluoroalkyl substances (PFAS) are used in various industrial products; however, they pose serious health risks. In this study, soil, soil gas, and groundwater samples were collected at a PFAS manufacturing facility in New Jersey, USA, to determine the presence and distribution of PFASs from the soil surface to groundwater and at various distances from the presumed source. Fluorotelomer alcohols (FTOHs) were detected in soil (< 0.26-36.15 ng/g) and soil gas (160-12,000 E µg/m3), while perfluorinated carboxylic acids (PFCAs) were found in soil (4.3-810 ng/g), soil gas (<0.10-180 µg/m3), and groundwater (37-49 µg/L). FTOH and PFCA concentrations decreased as the distance from the presumed source increased, suggesting that PFCAs are likely to migrate in groundwater, whereas FTOHs primarily move in the vapor phase. The presence of PFAS in the groundwater, soil, and soil gas samples indicate its potential for vapor intrusion; thus, some PFAS may contribute to indoor air inhalation exposure. To the best of our knowledge, this is the first report on the quantification of volatile PFAS in soil gas at a PFAS manufacturing facility.

Efficient and fast remediation of soil contaminated by per- and polyfluoroalkyl substances (PFAS) by high-frequency heating

This study presents a novel thermal technology (high-frequency heating, HFH) for the decontamination of soil containing per- and polyfluoroalkyl substances (PFAS) and aqueous film-forming foams (AFFFs). Ultra-fast degradation of short-chain PFAS, long-chain homologs, precursors, legacy PFAS, emerging PFAS was achieved in a matter of minutes. The concentrations of PFAS and the soil type had a negligible impact on degradation efficiency, possibly due to the ultra-fast degradation rate overwhelming potential differences. Under the current HFH experiment setup, we achieved near-complete degradation (e.g., >99.9%) after 1 min for perfluoroalkyl carboxylic acids and perfluoroalkyl ether carboxylic acids and 2 min for perfluoroalkanesulfonic acids. Polyfluoroalkyl precursors in AFFFs were found to degrade completely within 1 min of HFH; no residual cationic, zwitterionic, anionic, or non-ionic intermediate products were detected following the treatment. The gaseous byproducts were considered. Most of gaseous organofluorine products of PFAS at low-and-moderate temperatures disappeared when temperatures reached 890 °C, which is in the temperature zone of HFH. For the first time, we demonstrated minimal loss of PFAS in water during the boiling process, indicating a low risk of PFAS entering the atmosphere with the water vapor. The findings highlight HFH its potential as a promising remediation tool for PFAS-contaminated soils.