Per- and polyfluoroalkyl substances (PFAS) represent one of the most intractable challenges in contemporary water treatment, owing to the extreme strength of the C–F bond (∼488 kJ/mol), pronounced mobility, and detection at trace levels in drinking, surface, and groundwater worldwide. Conventional adsorbents such as granular activated carbon and ion-exchange resins offer practical robustness but suffer rapid saturation, slow kinetics, and poor selectivity toward short- and ultra-short-chain PFAS. Metal–organic frameworks (MOFs) have emerged as a transformative adsorbent class, offering ultra-high surface areas (up to ∼7000 m² g⁻¹), atomically tunable pore environments, and unsaturated metal sites that enable cooperative electrostatic, hydrophobic/fluorophilic, π-type, hydrogen-bonding, and Lewis acid–base interactions with diverse PFAS. This review critically synthesizes recent advances in MOF design across the IR, MIL, UiO, ZIF, PCN, PCP, and composite families, linking framework topology, linker chemistry, and metal-node identity to adsorption capacity, kinetics, and selectivity. We benchmark headline performance, for example, Zr-based PCN-999 achieving 1089 mg g⁻¹ for PFOA, approximately 50% above the previous MOF benchmark, against the practical realities of competing ions, natural organic matter fouling, and hydrolytic instability. To bridge the persistent laboratory-to-field gap, we propose a "metrics-first" evaluation framework that prioritizes hydrolytic stability, regeneration efficiency, and kinetic performance in complex water matrices over equilibrium capacity in deionized water. In order to solve the crucial selectivity–stability trade-off, this review presents a mechanism-guided, metrics-first paradigm that offers useful design guidelines for creating long-lasting and scalable MOF adsorbents for actual PFAS remediation. Finally, we contextualize MOF-based PFAS treatment within circular-economy principles and the United Nations Sustainable Development Goals (SDGs 6, 9, 12), outlining a process-engineering roadmap toward scalable, durable, and economically viable deployment.

Excessive contamination of per- and polyfluoroalkyl substances (PFAS) has posed a serious threat to water matrices. The development of efficient and eco-friendly water treatment technology is critically important. Herein, we report a non-thermal atmospheric pressure plasma jet (APPJ) that enables highly efficient degradation of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexanoic acid (PFHxA). Box-Behnken Design (BBD)-Response Surface Methodology (RSM) uncover an evaluation for plasmaalone and bubbles indicate that a combination on power and gas flow rate of 600 W; 4 L/min produce a stable plasma jet, a uniform bubble distribution throughout the reactor volume with a mean diameter of 3000-4000 mu m, and an optimal peak removal rate. The degradation rates after 10 min of treatment for PFOS, PFOA, and PFHxA had maximum removal rates of 86.68, 99.77, and 99.91% at a concentration of 50 mu g/L, respectively. Proposed degradation pathways suggest that chain breakdown begins at the hydrophobic head due to e((aq))(-), followed by center dot H acting as agents that break C-F bonds. Meanwhile, center dot OH acts as an agent for C-C bond scission, followed by decarboxylation-hydroxylation-elimination-hydrolysis (DHEH) processes until complete mineralization. Furthermore, several distinctive advantages of this study became evident with the low energy consumption to achieve maximum removal rates for PFOS, PFOA, and PFHxA, which only required 8.17, 2.70, and 1.70 kWh/m3, respectively. In addition, non-thermal APPJ is capable of treating PFAS-contaminated water without requiring additional catalysts while achieving high degradation efficiency and energy efficiency.

Sorption loss of per- and polyfluoroalkyl substances (PFAS) during filtration has been a known issue, impeding studies of PFAS partitioning between dissolved and particulate phases in water. In this study, we demonstrated the use of large-volume filtration through capsule filters to reduce PFAS sorption loss. Membrane materials of polypropylene (PP), poly(ether sulfone) (PES), nylon, polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), and glass fiber (GF) were selected to evaluate the sorption loss of 40 PFAS at environmentally relevant concentrations in pure water and seawater. The overall performance of the tested membranes ranks as follows: GF > PES approximate to PP > PTFE > PVDF > nylon. GF membranes exhibited the lowest sorption loss (<10% for most PFAS), and no isomeric composition was altered during filtration. Compared to pure water, seawater increased the sorption loss of ultralong-chain PFAS and precursors, likely due to high salinity and pH, which cause salting-out and cation-bridging effects and alter PFAS speciation. Our results highlight that large-volume filtration using GF membranes effectively minimizes the sorption loss of many legacy and emerging PFAS to achieve accurate dissolved-phase PFAS concentrations, enhancing current sampling methods for PFAS phase-partitioning studies, especially for PFAS in estuarine and coastal waters.

Per- and polyfluoroalkyl substances (PFAS) are a globally pervasive class of persistent and potentially toxic contaminants. This study investigates the prevalence, transport, and partitioning behavior of 19 PFAS within Georgica Pond (NY, USA), a shallow, temporarily-open estuary fed by groundwater historically impacted by aqueous film forming foam (AFFF). PFAS concentrations were measured in groundwater, groundwater seepage, sediments, and surface waters to evaluate the abundance, distribution, and the influence of environmental factors on PFAS fate and transport. Perfluorooctane sulfonate (PFOS; 32 ± 13 ng L-1) and perfluorohexane sulfonate (PFHxS; 30 ± 17 ng L-1) were the dominant PFAS detected in groundwater, while short-chain perfluoroalkyl acids (PFAAs) perfluorobutane sulfonate (PFBS) (9.8 ± 6.9 ng L-1) and perfluorohexanoic acid (PFHxA) (10.2 ± 5.7 ng L-1) were most abundant compounds in Georgica Pond surface waters. In sediments, PFBS (1.5 ± 0.91 μg kg-1) was most abundant in tributaries, while 6:2 fluorotelomer sulfonic acid (6:2 FTS) (1.5 ± 0.91 μg kg-1 d.w) was dominant in estuarine sediments. ∑PFAS and individual PFAS concentrations in surface waters were significantly (p < 0.001) and inversely correlated with salinity, suggesting dilution and/or enhanced sorption of PFAS in marine waters. Additionally, ∑PFAS as well as PFBS and PFHxS concentrations in sediment were strongly and significantly correlated with sediment organic matter content, indicating preferential accumulation in organic-rich substrates. These findings highlight the combined influence of salinity dynamics and in situ physical processes governing PFAS distribution and partitioning. Collectively, these results underscore the complex transformations of PFAS as they traverse the groundwater-to-sediment-to estuarine continuum that have direct implications for contaminant persistence and bioavailability.

Hydrophobic ion pairing (HIP) was used as a novel pretreatment approach to enhance the removal of short-chain per- and polyfluoroalkyl substances (PFAS) by granular activated carbon (GAC). The formation of ion pairs between PFAS and cationic surfactants was tested through controlled batch experiments with varying types and dose of HIP (e.g., cetyltrimethylammonium chloride (CTAC)) and surface tension measurements. Interactions between PFAS and CTAC were observed to be disturbed in high ionic strength solution, likely due to competitive electrostatic interactions from the presence of inorganic ions. Addition of CTAC (2 μM) prior to GAC treatment in batch adsorption experiments greatly improved the sorption of short-chain PFAS (C7) by 23-96%. The changes in sorption capacities were hypothesized to result from the altered physicochemical properties of the formed ion pair complex, thereby affecting its uptake on GAC. Both the linear free energy relationship (LFER) calculation and molecular dynamic (MD) simulation suggested that short-chain PFAS sorption was improved via enhanced hydrophobicity of formed ion pairs with a low self-assembly tendency, while long-chain PFAS sorption was inhibited due to the formation of large complexes with a high self-assembly tendency. Rapid small-scale column tests were performed for tap water spiked with an equal mass of perfluorobutanoate (PFBA), perfluorobutanesulfonate (PFBS), and perfluorooctanesulfonate (PFOS). The bed volume for 50% breakthrough was improved by 350% and 230% for PFBA and PFBS, respectively, in the presence of CTAC and PFOS.

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants in estuaries. In this study, 19 PFAS were quantified in surface waters, sediments, marine invertebrates (aquatic worms, Eastern oysters, and blue crab), and forage fish (Atlantic silverside, four-spine stickleback, mummichog, sheepshead minnow, and rainwater killifish) in an aqueous film forming foam (AFFF)-contaminated estuary, Georgica Pond (NY, USA). Carbon and nitrogen stable isotopes (δ13C and δ15N) were used to determine trophic position of organisms and to identify modes of PFAS exposure. The influence of salinity (8 to 26 practical salinity units, PSU) on the relative and absolute abundance of PFAS in all matrices was also investigated. Eleven long- and short-chain perfluoroalkyl acids (PFAAs) were found to have bioaccumulation potential (bioaccumulation factor, BAF; biota-sediment accumulation factor, BSAF) and were positively correlated with relative trophic position. Among these, long-chain PFAAs (perfluorohexanesulfonic acid, PFHxS; perfluorooctane sulfonic acid, PFOS; perfluorooctanoic acid, PFOA; perfluorononanoic acid, PFNA) were the greatest contributors to total body burden and bioaccumulated in all organisms, with PFOS (log BAF = 3.55 ± 0.83) and PFNA (log BAF = 3.17 ± 0.46) having the highest mean values of all compounds. PFOS was present in all biota samples and concentrations significantly increased with food web trophic position (ranging from 0.18 to 777 μg kg-1). Perfluorobutane sulfonic acid (PFBS) was also ubiquitous among all organisms, bioaccumulating in both invertebrate and vertebrate species. Total PFAS concentrations in aquatic worms were significantly higher in lower salinity water while the PFAS profile of Eastern oysters shifted from predominately perfluorocarboxylic acids (66 % of total composition) to perfluorosulfonic acids (62 %) as the ecosystem transitioned from low (9 PSU) to high (25 PSU) salinity. Collectively, this study demonstrates the utility of applying δ13C and δ15N to determine bioaccumulation patterns of both legacy PFAS and short-chain replacement compounds and underscores how shifts in salinity can alter the concentration and speciation of PFAS in estuaries.

The widespread detection of per- and polyfluoroalkyl substances (PFAS) in environmental compartments across the globe has raised several health concerns. Destructive technologies that aim to transform these recalcitrant PFAS into less toxic, more manageable products, are gaining impetus to address this problem. In this study, a 9 MeV electron beam accelerator was utilized to treat a suite of PFAS (perfluoroalkyl carboxylates: PFCAs, perfluoroalkyl sulfonates, and 6:2 fluorotelomer sulfonate: FTS) at environmentally relevant levels in water under different operating and water quality conditions. Although perfluorooctanoic acid and perfluorooctane sulfonic acid showed >90% degradation at <500 kGy dose at optimized conditions, a fluoride mass balance revealed that complete defluorination occurred only at/or near 1000 kGy. Non-target and suspect screening revealed additional degradation pathways differing from previously reported mechanisms. Treatment of PFAS mixtures in deionized water and groundwater matrices showed that FTS was preferentially degraded (similar to 90%), followed by partial degradation of long-chain PFAS (similar to 15-60%) and a simultaneous increase of short-chain PFAS (up to 20%) with increasing doses. The increase was much higher (up to 3.5X) in groundwaters compared to deionized water due to the presence of PFAS precursors as confirmed by total oxidizable precursor (TOP) assay. TOP assay of e-beam treated samples did not show any increase in PFCAs, confirming that e-beam was effective in also degrading precursors. This study provides an improved understanding of the mechanism of PFAS degradation and revealed that short-chain PFAS are more resistant to defluorination and their levels and regulation in the environment will determine the operating conditions of e-beam and other PFAS treatment technologies.

Per- and polyfluoroalkyl substances (PFAS) enter the marine food web, accumulate in organisms, and potentially have adverse effects on predators and consumers of seafood. However, evaluations of PFAS in meso-to-apex predators, like sharks, are scarce. This study investigated PFAS occurrence in five shark species from two marine ecosystems with contrasting relative human population densities, the New York Bight (NYB) and the coastal waters of The Bahamas archipelago. The total detected PFAS (& sum;PFAS) concentrations in muscle tissue ranged from 1.10 to 58.5 ng g(-1) wet weight, and perfluorocarboxylic acids (PFCAs) were dominant. Fewer PFAS were detected in Caribbean reef sharks (Carcharhinus perezi) from The Bahamas, and concentrations of those detected were, on average, similar to 79% lower than in the NYB sharks. In the NYB, & sum;PFAS concentrations followed: common thresher (Alopias vulpinus) > shortfin mako (Isurus oxyrinchus) > sandbar (Carcharhinus plumbeus) > smooth dogfish (Mustelus canis). PFAS precursors/intermediates, such as 2H,2H,3H,3H-perfluorodecanoic acid and perfluorooctanesulfonamide, were only detected in the NYB sharks, suggesting higher ambient concentrations and diversity of PFAS sources in this region. Ultralong-chain PFAS (C >= 10) were positively correlated with nitrogen isotope values (delta N-15) and total mercury in some species. Our results provide some of the first baseline information on PFAS concentrations in shark species from the northwest Atlantic Ocean, and correlations between PFAS, stable isotopes, and mercury further contextualize the drivers of PFAS occurrence.

Several studies have demonstrated that air-bubbling and foam fractionation techniques can efficiently remove long-chain PFAS from contaminated water. However, removing short-chain PFAS is challenging due to its lower surface activity and inability to form self-assembly structures at the air-water interface. In this study, we tested various additives, including salts, surfactants, and polymers, to improve short-chain PFAS (e.g., perfluorobutanesulfonic acid (PFBS) and perfluorobutanoic acid (PFBA)) removal in non-foaming solutions using a bench-scale system. We found that in the presence of cetyltrimethylammonium chloride (CTAC) and salt, air-bubbling can significantly remove 0.5 μg L-1 of PFBS and PFBA in deionized water by >99% (15 min) and 81% (60 min), respectively. The decline of surface tension and the formation of thin foam-like layers during bubbling, controlled by the concentration of CTAC, significantly improved the removal of short-chain PFAS. Adding anionic and neutral surfactants showed no removal of short-chain PFAS during bubbling, suggesting the importance of the electrostatic interactions between short-chain PFAS and the cationic CTAC. We observed a 1:1 molar ratio between CTAC and PFBS removed from the solution, suggesting the formation of ion pairs in the solution and enhancing the surface activity of the overall neutral (PFAS-CTAC) complex. A mass balance of the system revealed that the primary mechanism by which PFAS was removed from non-foaming waters was through aerosol generation (70−100%). Using the optimized condition, PFAS mixtures (short- and long-chain PFAS, including five recently regulated PFAS by USPEA, 2 nM each) in deionized water and natural groundwater were successfully removed to below detection (>99% removal; <2 ng L-1), except for PFBA (25−73% removal). These results provide an improved understanding of the mechanism by which PFAS is removed during foam fractionation and highlight the need for capturing aerosols enriched with PFAS to prevent secondary contamination.

A novel composite hydrogel bead composed of sodium alginate (SA) and aldehyde cellulose nanocrystal (DCNC) was developed for antibiotic remediation through a one-step cross-linking process in a calcium chloride bath. Structural and physical properties of the hydrogel bead, with varying composition ratios, were analyzed using techniques such as BET analysis, SEM imaging, tensile testing, and rheology measurement. The optimal composition ratio was found to be 40% (SA) and 60% (DCNC) by weight. The performance of the SA–DCNC hydrogel bead for antibiotic remediation was evaluated using doxycycline (DOXY) and three other tetracyclines in both single- and multidrug systems, yielding a maximum adsorption capacity of 421.5 mg g−1 at pH 7 and 649.9 mg g−1 at pH 11 for DOXY. The adsorption mechanisms were investigated through adsorption studies focusing on the effects of contact time, pH, concentration, and competitive contaminants, along with X-ray photoelectron spectroscopy analysis of samples. The adsorption of DOXY was confirmed to be the synergetic effects of chemical reaction, electrostatic interaction, hydrogen bonding, and pore diffusion/surface deposition. The SA–DCNC composite hydrogel demonstrated high reusability, with more than 80% of its adsorption efficiency remaining after five cycles of the adsorption–desorption test. The SA–DCNC composite hydrogel bead could be a promising biomaterial for future antibiotic remediation applications in both pilot and industrial scales because of its high adsorption efficiency and ease of recycling.

1,4-Dioxane is a recalcitrant pollutant in water and is ineffectively removed during conventional water and wastewater treatment processes. In this study, we demonstrate the application of nitrifying sand filters to remove 1,4-dioxane from domestic wastewater without the need for bioaugmentation or biostimulation. The sand columns were able to remove 61 ± 10% of 1,4-dioxane on average (initial concentration: 50 μg/L) from wastewater, outperforming conventional wastewater treatment approaches. Microbial analysis revealed the presence of 1,4-dioxane degrading functional genes (dxmB, phe, mmox, and prmA) to support biodegradation being the dominant degradation pathway. Adding antibiotics (sulfamethoxazole and ciprofloxacin), that temporarily inhibited the nitrification process during the dosing period, showed a minor effect in 1,4-dioxane removal (6–8% decline, p < 0.05), suggesting solid resilience of the 1,4-dioxane-degrading microbial community in the columns. Columns amended with sodium azide significantly (p < 0.05) depressed 1,4-dioxane removal in the early stage of dosing but followed by a gradual increase of the removal over time to >80%, presumably due to a shift in the microbial community toward azide-resistant 1,4-dioxane degrading microbes (e.g., fungi). This study demonstrated for the first time the resilience of the 1,4-dioxane-degrading microorganisms during antibiotic shocks, and the selective enrichment of efficient 1,4-dioxane-degrading microbes after azide poisoning. Our observation could provide insights into designing better 1,4-dioxane remediation strategies in the future.

The ecology and life-histories of white sharks make this species susceptible to mercury bioaccumulation; however, the health consequences of mercury exposure are understudied. We measured muscle and plasma total mercury (THg), health markers, and trace minerals in Northwest Atlantic white sharks. THg in muscle tissue averaged 10.0 mg/kg dry weight, while THg in blood plasma averaged 533 mu g/L. THg levels in plasma and muscle were positively correlated with shark precaudal length (153-419 cm), and THg was bioaccumulated proportionally in muscle and plasma. Nine sharks had selenium:mercury molar ratios in blood plasma >1.0, indicating that for certain individuals the potential protective effects of the trace mineral were diminished, whereas excess selenium may have protected other individuals. No relationships between plasma THg and any trace minerals or health markers were identified. Thus, we found no evidence of negative effects of Hg bioaccumulation, even in sharks with very high THg.

Although 1,4-dioxane contamination of drinking water is primarily associated with historical disposal practices and unintended industrial releases, the abundant presence of 1,4-dioxane in personal care and cleaning products and subsequent releases to domestic wastewater serves as a constant source of contamination of water resources. Drinking water contamination of 1,4-dioxane from the use of consumer products is currently underappreciated, in many cases unrecognized, and, as a result, few efforts have been dedicated to understanding this ongoing issue. A few U.S. states, like New York and California, are proactively addressing this important issue by acknowledging the need to restrict 1,4-dioxane in consumer products. In this review we summarize the (i) occurrence of 1,4-dioxane in consumer products, (ii) pathways by which consumer products can contaminate drinking water, (iii) current policies surrounding 1,4-dioxane in consumer products, and (iv) future research needs.

Quaternized nanocellulose (QNC), synthesized in this study, showed improved removal of both short chain and long chain PFAS by increasing the electrostatic interactions between the anionic functional groups of PFAS and the cationic quaternary ammonium groups of QNC.

1,4-Dioxane is a contaminant of emerging concern that has been commonly detected in groundwater. In this study, a stable and robust 1,4-dioxane degrading enrichment culture was obtained from uncontaminated soil. The enrichment was capable to metabolically degrade 1,4-dioxane at both high (100 mg L−1) and environmentally relevant concentrations (300 μg L−1), with a maximum specific 1,4-dioxane degradation rate (qmax) of 0.044 ± 0.001 mg dioxane h−1 mg protein−1, and 1,4-dioxane half-velocity constant (Ks) of 25 ± 1.6 mg L−1. The microbial community structure analysis suggested Pseudonocardia species, which utilize the dioxane monooxygenase for metabolic 1,4-dioxane biodegradation, were the main functional species for 1,4-dioxane degradation. The enrichment culture can adapt to both acidic (pH 5.5) and alkaline (pH 8) conditions and can recover degradation from low temperature (10°C) and anoxic (DO < 0.5 mg L−1) conditions. 1,4-Dioxane degradation of the enrichment culture was reversibly inhibited by TCE with concentrations higher than 5 mg L−1 and was completely inhibited by the presence of 1,1-DCE as low as 1 mg L−1. Collectively, these results demonstrated indigenous stable and robust 1,4-dioxane degrading enrichment culture can be obtained from uncontaminated sources and can be a potential candidate for 1,4-dioxane bioaugmentation at environmentally relevant conditions. •1,4-Dioxane degrading enrichment was obtained from uncontaminated soil. • The enrichment culture could degrade 1,4-dioxane to below 10 μg L−1. •Low Ks and low cell yield of the enrichment benefit its application in bioremediation.

The application of electron beam technology for water treatment has been proposed as a faster & safer approach to decomposing persistent contaminants, because it can rapidly generate high amounts of both oxidizing and reducing reactive species without added chemicals.

Background The application of wastewater-based epidemiology to track the outbreak and prevalence of coronavirus disease (COVID-19) in communities has been tested and validated by several researchers across the globe. However, the RNA-based surveillance has its inherent limitations and uncertainties. Objective This study aims to complement the ongoing wastewater surveillance efforts by analyzing other chemical biomarkers in wastewater to help assess community response (hospitalization and treatment) during the pandemic (2020–2021). Methods Wastewater samples ( n = 183) were collected from the largest wastewater treatment facility in Suffolk County, NY, USA and analyzed for COVID-19 treatment drugs (remdesivir, chloroquine, and hydroxychloroquine (HCQ)) and their human metabolites. We additionally monitored 26 pharmaceuticals including common over-the-counter (OTC) drugs. Lastly, we developed a Bayesian model that uses viral RNA, COVID-19 treatment drugs, and pharmaceuticals data to predict the confirmed COVID-19 cases within the catchment area. Results The viral RNA levels in wastewater tracked the actual COVID-19 case numbers well as expected. COVID-19 treatment drugs were detected with varying frequency (9–100%) partly due to their instability in wastewater. We observed a significant correlation ( R = 0.30, p < 0.01) between the SARS-CoV-2 genes and desethylhydroxychloroquine (DHCQ, metabolite of HCQ). Remdesivir levels peaked immediately after the Emergency Use Authorization approved by the FDA. Although, 13 out of 26 pharmaceuticals assessed were consistently detected (DF = 100%, n = 111), only acetaminophen was significantly correlated with viral loads, especially when the Omicron variant was dominant. The Bayesian models were capable of reproducing the temporal trend of the confirmed cases. Impact In this study, for the first time, we measured COVID-19 treatment and pharmaceutical drugs and their metabolites in wastewater to complement ongoing COVID-19 viral RNA surveillance efforts. Our results highlighted that, although the COVID-19 treatment drugs were not very stable in wastewater, their detection matched with usage trends in the community. Acetaminophen, an OTC drug, was significantly correlated with viral loads and confirmed cases, especially when the Omicron variant was dominant. A Bayesian model was developed which could predict COVID-19 cases more accurately when incorporating other drugs data along with viral RNA levels in wastewater.

We determined concentrations of Hg, Pb, Cd, Cr, As, Ni, Ag, Se, Cu, and Zn in muscle tissue of six commonly consumed Long Island fish species (black seabass, bluefish, striped bass, summer flounder, tautog, and weakfish, total sample size = 1211) caught off Long Island, New York in 2018 and 2019. Long-term consumption of these coastal fish could pose health risks largely due to Hg exposure; concentrations of the other trace elements were well below levels considered toxic for humans. By combining the measured Hg concentrations in the fish (means ranging from 0.11 to 0.27 mg/kg among the fish species), the average seafood consumption rate, and the current US EPA Hg reference dose (0.0001 mg/kg/d), it was concluded that seafood consumption should be limited to four fish meals per month for adults for some fish (bluefish, tautog) and half that for young children. Molar ratios of Hg:Se exceeded 1 for some black seabass, bluefish, tautog, and weakfish.

Advanced oxidation processes (AOPs) are popular technologies employed across the U.S. for wastewater reclamation and drinking water treatment of recalcitrant chemicals. Although there is consensus about the ineffectiveness of AOPs to treat perfluoroalkyl substances (PFASs; not polyfluoro compounds by definition here), there is a lack of field data demonstrating their impact on the transformation of unknown PFAS precursors during groundwater treatment. In this study, the fate of PFASs in seven pilot-scale AOPs, including four different technologies (UV/H2O2, UV/Cl2, UV/TiO2, and O3/H2O2), was assessed at four drinking water systems across New York State (NYS), USA. Seven of 18 PFASs were detected in the influent at concentrations ranging from below method detection to 64 ng/L. Across all systems, all detected PFASs showed an increase in concentration after treatment presumably due to unknown precursor transformation with specific increases for perfluorobutane sulfonate (PFBS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorohexane sulfonate (PFHxS), perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorononanoic acid (PFNA) averaging 405 (range: 0 - 1220) %, 1.0 (-7 - 9) %, 3.8 (0 - 9.5) %, 3.3 (-11 - 13) %, 14 (0 - 48) %, 13 (3 - 25) %, and 2 (0 - 5.2) %, respectively. The increase in PFAS concentration was dependent on UV and oxidant dose, further confirming that transformation reactions were occurring due to AOPs similar to a total oxidizable precursor assay. At one of the sites, PFOA levels exceeded the current NYS drinking water standard of 10 ng/L after, but not before treatment, highlighting the importance of considering the potential impact of AOP on treated water quality when designing treatment systems for regulatory compliance. The increase in PFAS concentration in the AOP systems positively correlated (r = 0.91) with nitrate levels in groundwater, suggesting that onsite septic discharges may be an important source of PFAS contamination in these unsewered study areas. Results from this pilot-scale demonstration reveal that hydroxyl radical-based AOPs, although ineffective in treating PFASs, can help to reveal the true extent of PFAS contamination in source waters.