Per- and polyfluoroalkyl substances (PFAS) associated with contamination from aqueous film forming foams are persistent, mobile contaminants that pose risks to groundwater and ecosystems. This study evaluated the effectiveness of granular activated carbon (GAC) application (1% w/w), with and without vegetation cover (perennial ryegrass), in reducing PFAS mobility under controlled laboratory-based rainfall simulation conditions using trays with (L50 ×W20 ×H5cm) dimensions. Two soils with contrasting textures but similar PFAS contamination levels were used in the experiment. Leaching behaviour was evaluated over one year with simulated rainfall events using the laboratory rainfall simulator, capturing both infiltration and surface runoff, as well as particulates in the runoff. PFAS mobility was influenced by soil texture, groundcover and wetting and drying cycles. Soil A (sandy clay loam) generated more runoff, while Soil B (sandy loam) allowed greater initial infiltration. Perfluorooctane sulfonic acid (PFOS) concentration was increased in the runoff of untreated soil after a prolonged drying cycle due to the upward flux of PFOS during the drying period. GAC reduced PFAS concentrations by up to 97% in runoff and 99% in infiltration across both soil types, even over a year with multiple wetting and drying cycles. Groundcover initially increased PFAS concentrations in runoff, likely due to upward transport and evapotranspiration, but this effect diminished as vegetation was established. Combined GAC and vegetation treatments achieved > 99% PFAS reduction in most cases, with plant effects more evident after 60 days. These findings support in-situ GAC application, with or without vegetation, as a viable approach for managing PFAS-contaminated soils. Plants may cause a temporary increase in PFAS mobility during the initial period following plant application, with or without GAC, and management practices should account for this risk.

Per- and polyfluoroalkyl substances (PFAS) represent a large—and structurally diverse—group of contaminants that have become ubiquitous in our environment. PFAS are all extremely persistent while some are also bioaccumulative, mobile and/or toxic, which gives rise to significant environmental and health concerns. Despite more than a decade of intensive research, the management of PFAS is still associated with considerable challenges. It is evident that a holistic approach is required to address the challenging global problem of PFAS. This roadmap features expert perspectives from world-renowned leading researchers and practitioners on how best to manage PFAS. The 15 topics cover different facets of the complex PFAS issue, providing a multidisciplinary and multisectoral overview. For each topic, we reflect on the current status of knowledge and offer recommendations on science and technology advances that will help meet current and future challenges. Taken together, the 15 topics cover the entire life cycle of PFAS—from their sources to their destruction. Important themes such as monitoring and analysis, understanding and predicting fate, source controls (regulation and replacement), and existing and emerging strategies for remediation (capture and destroy) are highlighted throughout the roadmap. Overall, there are many recent scientific and technological advancements that show promise for the management of PFAS. However, it is also clear that there is no ‘silver bullet’ and multifaceted solutions will be needed. Long-term success hinges on sustained collaboration among researchers, policymakers, industries, and communities, which we hope this roadmap will help to catalyze.

An increasingly common technique for managing per- and polyfluoroalkyl substances (PFAS)-contaminated vadose soils is immobilisation using sorbents. However, uncertainty remains regarding the long-term stability of PFAS immobilisation. This study investigated the effects of different environmental aging processes, physical (wetting-drying cycles), chemical, and biological, on the performance of widely used sorbents for PFAS immobilisation in soil using accelerated aging to simulate long-term environmental conditions. Six sorbents were evaluated, including two granular activated carbons (GAC), two powdered activated carbons (PAC), colloidal activated carbon (CAC), and biochar. Simulated physical and biological aging caused the greatest reductions in sorption efficiency, likely due to pore blockage, as confirmed by material characterisation, including surface area measurement and scanning electron microscopic images. Sorbent type significantly influenced performance, with PAC being the least affected by aging and biochar the most susceptible. When soils and sorbents were aged together, sorbent responses differed between soil types, with sorption efficiency decreasing after chemical aging in sandy soil and after physical aging in high-clay soil compared with other aging treatments. Despite these deliberately harsh simulated conditions, activated carbon-based sorbents remained highly effective, maintaining over 85% PFAS immobilisation in most scenarios, including highly contaminated soils (∑PFAS > 20 mg/kg). Overall, these findings demonstrate that although aging alters sorbent properties, activated carbon-based sorbents remain durable and effective for sustainable PFAS management under diverse environmental conditions.

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.

The potential of kinetic passive samplers to monitor per and polyfluoroalkyl substance (PFAS) concentrations in wastewater treatment plants (WWTPs) was evaluated using microporous polyethylene tube (MPT) passive samplers containing hydrophilic-lipophilic-balanced (HLB) or weak-anion-exchange (WAX) sorbents. Sampling rates (R-s) from 28 day deployments in WWTP effluent were consistent with principal resistance to PFAS accumulation in wastewater-filled micropores of the polyethylene tube. Considering both sorbents, PFAS R-s in the influent were smaller than in the effluent by a factor of 3.7, attributed to micropore clogging from a colloidal material but not biofilm formation. Combined Isolute ENV+ R-s values in the influent and effluent were 2.1 times larger than for Evolute WAX. Exploring their wider applicability, samplers with Sepra ZT-WAX were deployed in six other WWTPs with varying catchment characteristics. R-s values were significantly greater than those of Evolute WAX, indicating cationic charge center possession alone is an insufficient criterion for sorbent performance. Based on longer linear uptake timespans (e.g., >10(4) days for PFOA) and provision of time-weighted average concentrations, Evolute WAX was the best sorbent investigated. PFAS concentrations in wastewater derived from MPT samplers gave comparable accuracy to current grab sampling methods (i.e., EPA Method 1633). Findings demonstrate that MPT samplers are useful tools for monitoring PFAS in WWTPs.

Per- and polyfluoroalkyl substances (PFAS) are a broad group of persistent organic compounds with vastly differing physicochemical and toxicological properties. Some jurisdictions have proposed to regulate PFAS as a single class to overcome the limitations of regulating such a diverse group on a chemical-by-chemical basis. Implications of regulating PFAS as a single class have been discussed for PFAS production and use, but equivalent discussion of implications for managing contaminated sites is largely lacking. This opinion piece summarizes the views of a group of environmental consultants, environmental regulators, land managers, and academics with significant experience in researching or managing PFAS. The group considered that neither a single PFAS class approach nor a chemical-by-chemical approach is well suited to managing risks from PFAS in a contaminated site setting, and defining PFAS subgroups would have value. Second, some but not all in the group, hypothesize that PFAS properties that drive fate and transport are those that influence toxicity and bioaccumulation in animals. This may be a valuable observation for future discussions on dividing PFAS into subclasses for contaminated site regulation based on physicochemical properties rather than purely structural definitions.

The historical use and storage of aqueous film-forming foams (AFFF) containing per- and poly-fluoroalkyl substances (PFAS) at a range of sites including airports, defence, and port facilities have resulted in a legacy of contaminated infrastructure such as concrete. Contaminated concrete constitutes an ongoing source of PFAS contamination requiring management to ensure the protection of human health and the environment. In this study, modified Leaching Environmental Assessment Framework (LEAF) and Australian Standard Leaching Procedure (ASLP) were used to examine the leachability of PFAS, specifically, perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorohexanoic acid (PFHxA) from AFFF-contaminated concrete collected from an Australian Defence Fire Training Area (FTA). In general, PFAS readily leached from intact contaminated concrete monoliths with the cumulative proportion (%) decreasing in the order: PFHxA (>95%) > PFOS (26-84%) approximate to PFHxS (14-78%) > PFOA (<1-54%). Higher leachability for PFHxA from concrete is consistent with previous findings for solids, however, inconsistent for PFOA with higher retention (lower leachability) in concrete as compared to PFOS. Duration of exposure to water (0.5-48 h) and temperature (25 degrees C and 50 degrees C) had little influence on the proportion of PFAS leachability from powdered concrete. A higher proportion of PFAS leached from a <2 mm concrete powder size fraction as compared to 2-20 mm and 20 mm size fractions. This behavior reflects an increase in surface area with decreasing concrete particle size. Reducing the particle size could enhance PFAS removal from waste concrete.

Monitoring contamination from per- and polyfluoroalkyl substances (PFASs) in water systems impacted by aqueous film-forming foams (AFFFs) typically addresses a few known PFAS groups. Given the diversity of PFASs present in AFFFs, current analytical approaches do not comprehensively address the range of PFASs present in these systems. A suspect-screening and nontarget analysis (NTA) approach was developed and applied to identify novel PFASs in groundwater samples contaminated from historic AFFF use. A total of 88 PFASs were identified in both passive samplers and grab samples, and these were dominated by sulfonate derivatives and sulfonamide-derived precursors. Several ultrashort-chain (USC) PFASs (≤C3) were detected, 11 reported for the first time in Australian groundwater. Several transformation products were identified, including perfluoroalkane sulfonamides (FASAs) and perfluoroalkane sulfinates (PFASis). Two new PFASs were reported (((perfluorohexyl)sulfonyl)sulfamic acid; m/z 477.9068 and (E)-1,1,2,2,3,3,4,5,6,7,8,8,8-tridecafluorooct-6-ene-1-sulfonic acid; m/z 424.9482). This study highlights that several PFASs are overlooked using standard target analysis, and therefore, the potential risk from all PFASs present is likely to be underestimated.

Per- and poly-fluoroalkyl substances (PFAS) are prevalent environmental contaminants detected in materials such as soils, biosolids, and wastes. Understanding PFAS leaching is crucial for assessing risks associated with leaving impacted material in place, reuse, or disposal. However, there is limited guidance on laboratory methods to measure extent and rate of leaching. This review aims to identify the best methods for assessing PFAS leaching that are reflective of relevant release scenarios. Various methods have been applied to assess PFAS leaching from contaminated materials. The most common are batch leaching methods that simulate particular conditions (e.g. rainfall, landfill), with the intention of providing conservative estimates (worst-case scenarios) of cumulative PFAS release over time. Columns, static leaching, and rainfall simulators are also used to simulate less aggressive field-like conditions. While less common, pan and suction lysimeters have been used to measure PFAS leaching in situ. Most methods use saturated conditions that do not account for the possible influence of air–water interface accumulation and wetting–drying cycles on leaching. A notable gap is the scarcity of data benchmarking laboratory-leached concentrations with real-world PFAS concentrations. Establishing this relationship is crucial for reliable laboratory protocols. This article reviews methods for estimating leaching of PFAS from contaminated materials. Given the variety of methods, selecting those that best simulate assessment objectives is essential. Specific scenarios requiring PFAS leaching assessment, such as leaving materials in place, reuse, and disposal, are discussed. The knowledge gaps presented could be used to improve existing leaching methods for better predictions and understanding of PFAS leachability.

Ultrashort-chain per- and polyfluoroalkyl substances (PFASs) are an emerging class of contaminants that remain underexplored in environmental research. This study examines their distribution in Australian drinking tap water, environmental waters, and wastewaters (n = 63) using nontarget analysis via high-resolution mass spectrometry. Thirteen ultrashort-chain PFASs were identified, including novel compounds such as perfluoroalkane sulfinate (PFPSi), hydrogen-substituted perfluoroalkyl carboxylate (H-PFCA), chloro-perfluoroalkanesulfonate (Cl-PFSA), and bis-perfluoroalkyl sulfonamide (bis-FASIs). Perfluoropropanesulfonic acid (PFPrS) was the most prevalent, detected in 83% of surface, groundwater, and wastewater samples, and in 67% of tap water samples from major Australian cities. Concentrations of PFPrS and perfluoroethanesulfonic acid (PFEtS) ranged from <0.02 to 8000 ng/L. Ultrashort-chain perfluoroalkane sulfonamides (FASAs) and perfluoroalkane sulfates (PFA-OS) were predominantly found in wastewater. These findings highlight the widespread presence of ultrashort-chain PFASs in Australian water systems and underscore the need for ongoing monitoring and research due to their potential ecological and human health impacts. This study provides essential baseline data that could inform future regulatory measures and environmental management strategies.

Effective monitoring tools, including passive samplers, are essential for the wide range of per- and polyfluoroalkyl substances (PFASs) in aquatic matrices. However, knowledge of the extent and mechanisms of PFASs sorption with sorbents in a passive sampling context is limited. To address this, sorption behavior of 45 anionic, neutral and zwitterionic PFASs ranging in perfluorocarbon chain length (C3-C16) and functional groups with 11 different commercial sorbents (cross-linked β-cyclodextrin polymers, activated carbon, anion exchange (AE), cation exchange, hydrophilic-lipophilic balanced (HLB) and non-polar) was investigated. A broad range of equilibrium sorbent-MilliQ water (MQ) distribution coefficients (Kd) were observed (10-1.95 to 108.30 mL g-1). Similar sorbent types (e.g., various AE and HLB sorbents) exhibited very different sorption behavior, likely due to their different polymeric structures and relative importance of sorbate/sorbent interactions other than coulombic interactions. HLB and AE with hydroxyl functionalities are most effective for sampling of the full suite of PFASs. Reduced sorptive affinity was observed in the presence of matrix co-constituents in wastewater influent for most PFASs. HLB had the smallest reduction in log Kd in wastewater suggesting that these sorbents are appropriate for applications in complex matrices. Sufficient sorbent capacity was observed for linear uptake of many target analytes which facilitates passive sampling.

Purpose of Review The unique properties of per- and polyfluoroalkyl substances (PFASs) have seen their widespread adoption, subsequent accumulation in the environment and concern regarding potential environmental effects. Globally, airfields and paved firefighting training surfaces are hotspots for accumulation of PFAS due to extensive use of aqueous film-forming foams (AFFF). Evidence from contaminated concrete and asphalt airfield and training pavements suggests they may serve as an enduring PFAS source. This review investigates sealants as remediation technologies to minimise PFAS mobilisation from pavements drawing on current knowledge of remediation options for soils, sediments, surface and groundwaters. Recent Findings The review did not identify any published sealant information specific to PFAS. Our analysis showed that surface and penetrative sealants may offer an immediate solution via encapsulation of PFAS residues in concrete and asphalt. The most promising surface sealants likely to minimise water ingress and PFAS leaching are selected polymers and (modified) bitumen, owing to the relatively low cost, good adhesion, trafficability and chemical, heat and UV resistance. Potential also exists to enhance PFAS immobilisation using additives to absorb or otherwise chemically bind PFAS. Prospective penetrative sealants include silicates or siloxanes that bind to internal mineral surfaces and/or fill pores to restrict PFAS mobility. It is likely that combinations of surface and penetrative sealants will be required to meet functional, operational and management requirements with respect to new or existing contamination in concrete or asphalt pavements. Summary At present, few if any sealants have been evaluated for their ability to bind or mitigate PFAS mobility. This review serves as a starting point for further studies to evaluate their short or long-term effectiveness in immobilisation of PFAS residues in in situ or ex situ concrete and asphalt. Several knowledge gaps along with suggestions for future research have been made.

Historical use of aqueous film forming foams (AFFF) containing per- and poly-fluoroalkyl substances (PFAS) for fire-fighting activities has contributed to widespread contamination of infrastructure which can represent an ongoing source of PFAS to the surrounding environment. A concrete fire training pad with historical use of Ansulite and Lightwater AFFF formulations had PFAS concentrations measured to quantify spatial variability of PFAS within the pad. Surface chips and whole cores of concrete through to the underlying aggregate base were collected over the 24 × 9 m concrete pad and depth profiles of PFAS concentrations in nine cores were analysed. PFOS and PFHxS dominated the PFAS for surface samples, along the depth profile of cores and in the underlying plastic and aggregate material, with substantial variability in the concentrations of PFAS in the samples. Although there was variability of individual PFAS along the depth profile, higher surface concentrations of PFAS generally followed the designed movement of water across the pad. Total oxidisable precursor (TOP) assessments of one core indicated additional PFAS were present along the entire length of the core. This study highlights concentrations of PFAS (up to low μg/kg) from historical use of AFFF can occur throughout concrete, with the variable concentrations throughout the profile.

Immobilisation/stabilisation is one of the most developed and studied approaches for treating soils contaminated with per-and poly-fluoroalkyl substances (PFAS). However, its application has been inhibited by insufficient understanding of the effectiveness of added soil sorbents over time. Herein, we present results on the effec-tiveness of select carbon-based sorbents, over 4 years (longevity) and multiple laboratory leaching conditions (durability). Standard batch leaching tests simulating aggressive, worst-case scenario conditions for leaching (i. e., shaking for 24-48 h at high liquid/solid ratios) were employed to test longevity and durability of stabilisation in clay-loam and sandy-loam soils historically contaminated with PFAS (2 and 14 mg/kg n-ary sumation 28 PFAS). The different sorbents, which were applied at 1-6% (w/w), reduced leaching of PFAS from the soils to varying de-grees. Among the 5 sorbents tested, initial assessments completed 1 week after treatment revealed that 2 powdered activated carbon (PAC) sorbents and 1 biochar were able to reduce leaching of PFAS in the soil by at least 95%. Four years after treatment, the performance of the PAC sorbents did not significantly change, whilst colloidal AC improved and was able to reduce leaching of PFAS by at least 94%. The AC-treated soils also appeared to be durable and achieved at least 95% reduction in PFAS leaching under repetitive leaching events (5 times extraction) and with minimal effect of pH (pH 4-10.5). In contrast, the biochars were affected by aging and were at least 22% less effective in reducing PFAS leaching across a range of leaching conditions. Sorbent per-formance was generally consistent with the sorbent's physical and chemical characteristics. Overall, the AC sorbents used in this study appeared to be better than the biochars in stabilising PFAS in the long term.

Immobilisation/stabilisation is one of the most developed and studied remediation approaches for treating soils contaminated with per- and polyfluoroalkyl substances (PFAS). However, its application has been inhibited by insufficient understanding of the effectiveness of added soil sorbents over time. Herein, we present results on effectiveness of select carbon-based sorbents with different properties, under long-term dry storage over 4 years (longevity) and multiple laboratory leaching conditions (durability). Reduction of leaching of a range of PFAS from contaminated soils was tested using 2 powdered activated carbon (AC) sorbents, 1 colloidal AC, and 2 biochars applied at 1-6%. Standard batch leaching tests simulating aggressive, worst-case scenario conditions for leaching were employed to test longevity and durability of stabilisation in clayey and sandy soils at concentrations typical of contaminated sites (2 and 14 mg/kg perfluorooctane sulfonate, PFOS). The different sorbents reduced leaching of PFAS from the soils, albeit to varying degrees. Among the 5 sorbents, 2 powdered AC and 1 biochar were initially able to reduce leaching of perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA) and PFOS by at least 95%. Aging for 4 years did not significantly affect the performance of the powdered AC sorbents with respect to PFAS leaching, though an improvement was observed in the soils treated with colloidal AC, reaching close to 95% reduction in leachable PFHxS, PFOS and PFOA. The AC-treated soils also appeared to be durable – still achieving at least 95% reduction in leaching under repetitive leaching events and with minimal effect of pH. In contrast, the biochars were affected by aging and were less effective in reducing PFAS leaching across a range of leaching conditions (reductions being lower than 95%). Results were generally consistent with the sorbent’s measured physical and chemical characteristics.

Environmental context In previous instances of global impacts from chemicals, there were significant gaps between the onset of use and observations that triggered management. The lessons of the past have informed the development of strong paradigms for chemical management, but at some point, major impacts will again emerge, not covered by these paradigms. Holistic observation of the environment and collaborative reporting are needed to identify signals of future major issues. Abstract Increasing concern over per- and polyfluoroalkyl substances (PFAS) in the environment, in the last decade, has sparked an interest in emerging chemicals more broadly, leading to the development or strengthening of many useful programs for understanding and prioritising environmental hazards and risks for chemicals. While important and useful, such efforts mostly rely on comparing chemical properties with paradigms generated from previous environmental issues. The lessons of the past demonstrate that, at some point, major challenges to our existing paradigms will eventuate. Key to addressing these challenges is our ability for early identification of ‘blind spots’ not covered by our existing paradigms. Furthermore, if we only look for gross observable changes in the environment, we will only ever be able to respond with reactive measures. We suggest that while various relevant monitoring programs are in place and have been proposed, encouraging those processes to look beyond existing hazard paradigms and look for more subtle environmental signals will improve the ability to respond proactively when harm is still limited.

The mobilization and transport of per- and poly-fluoroalkyl substances (PFASs) via surface runoff (runoff) from aqueous film-forming foam (AFFF)-contaminated soils during rainfall, flooding, or irrigation has not been thoroughly evaluated, and the effectiveness of carbonaceous sorbents in limiting PFASs in runoff is similarly unquantified. Here, laboratory-scale rainfall simulations evaluate PFAS losses in runoff and in leaching to groundwater (leachate) from AFFF-contaminated soils varying in texture, PFAS composition and concentration, and remediation treatment. Leaching dominated PFAS losses in soils with a concentration of ∑PFAS = 0.2-2 mg/kg. However, with higher soil PFAS concentrations (∑PFAS = 31 mg/kg), leachate volumes were negligible and runoff dominated losses. The concentration and variety of PFASs were far greater in leachates regardless of the initial concentrations in soil. Losses of PFASs were dependent on the C-chain length for leachates and more on the initial concentration in soil for runoff. Suspended materials did not meaningfully contribute to runoff losses. While concentrations of most PFASs declined significantly after the first rainfall event, desorption and transport in both runoff and leachates persisted over several rainfall events. Finally, results showed that sorption to AC mostly occurred during, not prior to, rainfall events and that 1% w/w AC substantially reduced losses in runoff and leachates from all soils.

Poly and perfluorinated alkyl substances (PFASs) are persistent organic pollutants (POPs) that are highly resistant to environmental degradation, and have been detected in a broad range of terrestrial and aquatic species. Portunid crabs have been shown to accumulate comparatively high concentrations of PFASs, but previous work examining depuration in crabs was inconclusive. Here, we trialled a novel experimental design to study depuration of PFASs from edible tissues of portunid crabs, using paired claw samples, and trial this design with Giant Mud Crab Scylla serrata exposed to the contaminant under natural conditions. We found evidence for depuration of perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA), but with depuration half-lives as high as 40 days (for PFOS). We also observed substantial variability in the data, including differences in PFAS concentrations between claws from the same individuals, potentially resulting from claw loss and re-growth prior to capture. These results have broad implications for assessing and minimising exposure risk in seafood species.