Per- and polyfluoroalkyl substances (PFAS) are common contaminants of drinking water globally. Due to their large number and diversity, extractable organofluorine (EOF) has been employed as a sum parameter measurement to capture known and unknown PFAS in environmental samples. However, current methods for determining drinking water EOF perform poorly for trifluoroacetic acid (TFA) and provide limited insights into the nature of unidentified fluorine occurring in samples. To address this, we developed and validated a solid-phase extraction procedure for EOF determination in drinking water with improved TFA recovery, which removes and/or accounts for different species of inorganic fluorine. The method produces two fractions: one containing mostly polar fluorinated substances (e.g., TFA, tetrafluoroborate, and trifluoromethanesulfonate) and another containing longer-chain PFAS. Hexafluorophosphate was distributed across both fractions. Application of the method to Stockholm drinking water revealed a closed fluorine mass balance in fraction I, predominantly (93%) consisting of TFA. In fraction II, however, 67% of the fluorine was unidentified, pointing to unknown fluorinated substance(s) with similar physical-chemical properties to PFAS in this fraction (e.g., perfluorooctanesulfonate). In addition to providing clues for identifying EOF, the method improves estimation of “PFAS Total” for comparison to limits under the European Drinking Water Directive.

Per- and polyfluoroalkyl substances (PFAS) are used in a wide range of different industrial and consumer applications. However, due to their extreme environmental persistence and their impacts on human and ecosystem health, PFAS have been subject to many regulatory activities, including initiatives to incentivize industry to transition toward PFAS-free alternatives. Although efforts have been made to map all uses of PFAS, work is still needed to provide an overview of their potential alternatives. Based on the functional substitution approach, this study develops an online database that documents all known uses of PFAS, describes the functions provided by PFAS in these uses, lists potential alternatives that can deliver equivalent or similar functions to PFAS, and evaluates the suitability of the identified alternatives to replace PFAS. Overall, the database lists 325 different applications of PFAS across 18 use categories. In total, 530 PFAS-free alternatives are identified. Based on a screening of potential concerns of the identified alternatives, their performance compared to PFAS, and their availability on the market, it is concluded that potentially suitable alternatives to PFAS are available for 40 different applications. For 83 applications, no alternatives could be identified at the time of the study and should be the focus of further research activities.

Increased awareness of pervasive per- and polyfluoroalkyl substances (PFAS) contamination and the need for zero-pollution treatment solutions necessitate the scientific and engineering community to respond urgently and systematically. Existing approaches lack reproducible and standardized methods to report the technological treatment capabilities. Consequently, it is difficult to compare innovations and accurately assess their potential. In this Perspective, we shed light on hurdles encountered in the lab-scale research and development of aqueous PFAS destruction technologies with a focus on chemical methods and offer recommendations for overcoming them. Best practices are provided for developing robust PFAS laboratory protocols covering crucial aspects such as experimental planning, sample storage and analysis, and waste management. Further, we present five criteria to standardize reporting on performance and advances in PFAS degrading technologies: 1) scope, 2) defluorination efficiency, 3) relative energy consumption, 4) material stability, and 5) unit process considerations. Through the dissemination of these insights, we aim to foster progress in the development of highly effective treatment solutions.

The Stockholm Convention and the EU REACH Regulation are two key pieces of legislation on chemicals at the global and European levels, respectively. Discussions have taken place on revising them. For instance, the European Commission is considering implementing the “essential-use” concept in the REACH Regulation to guide decision-making for phasing-out the use of the most harmful chemicals. By assessing 34 existing cases under the Stockholm Convention and 45 restrictions and 544 applications for authorization under the REACH regulation (as of November 2023), this study aims to capture how the essential-use concept may inform decision-making on exemptions and provide insights on its implementation. By conducting a detailed case study of the REACH restriction on intentionally added microplastics, this study also aims to explore how the existing data requirements in regulatory processes could be used in an essentiality assessment. Overall, this study suggests that the Stockholm Convention and the REACH Regulation already consider elements of the concept in their decision-making and that no drastic changes in the data requirements are necessary to apply the concept in decision-making processes.

This study investigated the particle size distribution and atmospheric transport potential of perfluoroalkyl carboxylic acids (PFCAs) and certain perfluoroalkyl ether carboxylic acids (PFECAs) emitted from a mega fluoropolymer industrial park (FIP) in China. Ambient aerosols sampled in a residential area near the FIP were separated by a cascade impactor into five size fractions (<0.15 to 12.15 μm). Homologues of PFCAs (C5-C11) and five PFECAs were frequently detected in the samples (detection frequencies 40-100%), albeit not in all size fractions. Perfluorooctanoic acid (PFOA) exhibited the highest concentrations (6.5 to 2900 pg m-3). A noticeable mass mode in the >1 μm size range was observed for PFCAs and PFECAs in the samples that were directly influenced by wind from the direction of the FIP. Based on the PFOA concentrations in the aerosol samples, the emission rate of PFOA to air from the FIP was estimated to be 0.4-1.3 t year-1. Modeling results demonstrated that around 67% of the PFOA air emission was transported in the atmosphere above 1500 m in a 7 day continuous emission scenario, implying that the PFOA on <12.15 μm particles undergoes long-range atmospheric transport after being emitted from the FIP.

Emissions of historical fluorinated processing aids used in fluoropolymer production are known to have contributed significantly to environmental levels of persistent perfluoroalkyl acids (PFAAs). Less is known about emissions of contemporary processing aids and the efficacy of technology used to contain them. To address this, we investigated the occurrence of hexafluoropropylene oxide dimer acid (HFPO-DA) and other per- and polyfluoroalkyl substances (PFAS) in airborne PM10 near a fluoropolymer production plant in the Netherlands. The 20-week high-volume air sampling campaign coincided with installation of emission abatement systems. HFPO-DA levels ranged from below detection limits to 98.66 pg m-3 when the wind came from the plant, and decreased to a maximum of 12.21 pg m-3 postabatement. Lagrangian dispersion modeling using FLEXPART revealed good concordance between measured and modeled HFPO-DA concentrations (Pearson’s r = 0.83, p ≤ 0.05, Wilmott’s d = 0.71, mean absolute error = 3.66 pg m-3), providing further evidence that the plant is a point source. Modeling also suggested that HFPO-DA could undergo long-range atmospheric transport with detectable HFPO-DA air concentrations predicted up to several thousand kilometers away. Besides HFPO-DA, the fluorinated processing aid 6:2 fluorotelomer sulfonate and the suspected polymerization byproducts, hydrogen-substituted perfluoroalkyl carboxylic acids, were also observed, highlighting the complex mixture of PFAS emitted by the plant.

The production and use of PFAS in some countries, coupled with uncertainties about their applications across Asia, underscore the urgent need to assess human exposure—particularly beyond China, Japan, and South Korea, which account for 80–90% of existing environmental PFAS studies. Exposure levels vary significantly across the region, with industrial activities, including textile and automotive manufacturing, contributing to severe contamination, especially in freshwater sources. Studies have detected PFAS in surface and groundwater across 20 Asian countries (∼3000 samples), sometimes at concerning concentrations. Contamination extends to drinking water and food products, further increasing human exposure risks. There is now substantial evidence, particularly from China, South Korea, and Japan, indicating a widespread presence of long-chain PFAS in human serum and breast milk. Additionally, replacement compounds and their degradation products, such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and the dimer and trimer acids of hexafluoropropylene oxide (HFPO-DA, and HFPO-TA), are increasingly detected in human samples in China, where they are produced. Although the situation in the rest of Asia is currently unclear due to limited data, given the widespread PFAS contamination in water and food sources in the studied areas of Asia, human exposure is highly likely. Beyond direct contamination, additional risk factors in certain Asian regions are likely to exacerbate exposure, including industrially impacted freshwater resources, self-supplied and untreated drinking waters, and high reliance on fish and seafood (including wastewater-fed fisheries) in some countries. Conversely, dietary patterns, such as vegetarianism in some regions (e.g. India), may influence PFAS exposure differently. Despite these concerns, PFAS regulations in Asia typically fall behind those in Western countries, resulting in significant gaps in risk assessment and regulatory oversight. There is also less pressure to systematically characterize exposure levels and associated health risks. This article examines the pathways of PFAS exposure in Asia, focussing on East Asia due to the availability of data. It examines the main factors contributing to exposure, including PFAS production and associated industries, as well as the consumption of contaminated food and water. The article also identifies future research needs aimed at enhancing the understanding and mitigation of PFAS risks in Asia.

Multiple target and suspect per- and polyfluoroalkyl substances (PFAS), including the replacement fluorinated processing aid perfluoro(2-ethoxy-2-fluoroethoxy)-acetic acid ("EEA"), were measured in both air and surface water in the vicinity of a fluoropolymer production plant (FPP) in Thornton-Cleveleys (United Kingdom) during sampling campaigns in 2021 and 2023, respectively. Targeted and suspect screening methods were conducted using ultrahigh-performance liquid chromatography (UHPLC) coupled with Q-Exactive HF Orbitrap high-resolution mass spectrometry (HRMS). Summed PFAS levels in water nearby the plant ranged from 30 to 22,542 ng/L and were dominated by perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl ether carboxylic acids (PFECAs), most notably perfluorooctanoic acid (PFOA; up to 20,624 ng/L), EEA (up to 1744 ng/L), H-PFOA (up to 1027 ng/L), and perfluorohexanoic acid (PFHxA; up to 650 ng/L). Additionally, various homologous series of PFAS suspects, such as hydrogen-substituted PFCAs (H-PFCAs), chlorine-substituted PFCAs (Cl-PFCAs), and monoether perfluoroether alkyl carboxylic acids (ME-PFECAs) were identified, some for the first time in Europe. In air, PFOA was detected in all but one sample collected 20 km from the plant at concentrations ranging from 0.51 to 2.50 pg/m3. The three air samples that showed detectable EEA concentrations also displayed evidence of long-chain targets and suspects and were associated with high wind speeds from a southwesterly direction. Overall, this study shows that this site continues to be a source of a complex mixture of legacy and scarcely monitored PFAS that occur in multiple environmental media. This highlights the importance of further research that assesses the toxicity of these substances and the resulting impacts on humans and wildlife.

It is now well understood that an individual’s unique characteristics arise from the intricate interaction between genes and a vast range of nongenetic factors. While only a small fraction of diseases can be solely attributable to genetics, studies of nongenetic factors have been sporadic and mostly focused on a single factor or limited factors. To address this imbalance, the concept of the exposome has emerged, offering a broader perspective on human health. The exposome represents the comprehensive collection of all physical, chemical, biological, and psychosocial factors to which individuals are exposed from conception onward, along with their internal biological responses, which collectively shape health outcomes. (1) Because of remarkable advances in measurement techniques and analytical methods, the exposome has become increasingly prominent in environmental and biomedical research. This paradigm shift has enabled the identification of causal relationships between nongenetic factors and specific health outcomes. For example, exposure to certain chemical mixtures, whether voluntary or involuntary, has been linked to the onset of various diseases and metabolic disorders. (2) Notably, recent exposome-wide association studies (EWAS) on aging and mortality within the UK Biobank, encompassing nearly half a million participants, have demonstrated that all-cause mortality is influenced more by the exposome than by the genome. (3) Despite these advancements, studying the exposome remains highly complex. Its dynamic nature, the wide diversity of exposures, and the continuous variation of these factors over a lifetime present significant challenges. To fully comprehend the exposome’s impact on health, a multidisciplinary approach is essential. Integration of expertise from diverse fields, such as analytical chemistry, toxicology, epidemiology, environmental science and engineering, clinical medicine, omic and data science, etc., is necessary. Such a comprehensive framework is key to unraveling the intricate connections between environmental exposures and human health. As we advance the frontiers of environmental and biomedical research, the exposome provides a critical pathway for understanding disease etiology, fostering personalized and preventive healthcare strategies, and offering a holistic view of the profound links between the environment and human health.