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Per- and polyfluoroalkyl substances (PFAS) are persistent, non-degradable chemicals that threaten ecological health and food safety in agricultural systems. Widespread contamination arises from the use of PFAS-polluted wastewater for irrigation and land application of polluted-biosolids, resulting in PFAS accumulation in soil and subsequent uptake by crops. Biochar, a cheap and readily available material produced from biomass through pyrolysis, has been recognized as an efficient and sustainable soil amendment to mitigate PFAS bioavailability; however, practical implementation remains challenging due to a lack of pilot-scale studies, limited understanding of biosolids-biochar-soil-plant interactions, and reduced effectiveness for short-chain PFAS.

This pilot study aimed to clarify the mechanisms by which biochar mitigates PFAS accumulation in plants and to explore strategies for enhancing its effectiveness. Large-pot experiments (50 kg sandy soil per pot) were conducted focusing on six PFAS: three perfluorocarboxylates (PFBA, PFOA, PFNA) and three perfluorosulfonates (PFBS, PFHxS, PFOS), representing short- to long-chain compounds. Two PFAS sources—irrigation wastewater (100 ng/mL) and biosolids (100 ng/g dry weight)—were compared. Two types of biochar—biosolid biochar (BBC) and pine biochar (PBC)—were separately applied to the sandy soils. Spinach was chosen as the model crop and cultivated outdoors in California from May to June 2025, with daily irrigation. PFAS concentrations in dried leaves and roots were quantified using LC-MS/MS, and the mitigation efficiency of biochar was assessed by comparing the bioconcentration factor ratio (BCFcontrol/BCFbiochar).

Mitigation was stronger for biosolid-derived PFAS compared to irrigation-derived PFAS. For example, biochar treatments decreased BCFs in leaves by 1–2-fold for irrigation sources but by 2–200-fold for biosolid sources, likely due to longer adsorption times and enhanced PFAS–biochar interactions in biosolid matrices.

BBC and PBC effectively reduced accumulation of PFBA, PFOA, PFNA, PFHxS, and PFOS in leaves and roots, with minimal influence on PFBS. Moreover, PBC yielded higher mitigation efficiency than BBC for long chain PFAS due to higher specific surface area and point of zero charge, and lower O/C ratio.

The interactions among biosolids-soil-biochar were investigated by varying the mixing sequence: PFAS-contaminated biosolids were either pre-mixed with BBC for 7 days prior to soil incorporation (premix) or mixed with soil and BBC simultaneously. Premixing enhanced mitigation of long-chain PFAS but diminished mitigation of short-chain PFAS, indicating competitive adsorption in which long-chain PFAS preferentially occupy biochar sorption sites.

In addition, PBC was post-heat treated to enhance its capacity to retain short-chain PFAS such as PFBA and PFBS. Compared with untreated PBC, this modification significantly improved mitigation efficiency, increasing the capacity (BCFcontrol/BCFbiochar) for PFBS from 1.5× to 3.9× and for PFBA from 1.6× to 50×, indicating that post-heat treatment is an effective strategy for short-chain PFAS control.

This work provides a pilot-scale demonstration of biochar-mediated PFAS mitigation under realistic soil conditions. The results highlight biochar as a practical and scalable solution for reducing PFAS bioavailability from both irrigation water and biosolid sources, supporting safer crop production and sustainable management of contaminated agricultural soils.

PFAS enter publicly owned treatment works (POTWs) through residential and industrial inputs and hauled-in wastes (e.g., landfill leachate, septage). Quarterly PFAS monitoring under recent NPDES permits highlights the increasing regulatory focus on POTWs, which do not produce PFAS. POTWs must address influent loads from industrial and domestic users, and there are limited treatment options, emphasizing the need for coordinated management strategies. The Massachusetts Department of Environmental Protection (MassDEP) recently undertook two statewide studies to improve understanding of PFAS occurrence, fate, and transport in wastewater systems and accelerate data collection: The PFAS and Residuals Technology and Management Study and the PFAS Testing Study at NPDES POTWs combined desktop analyses of regional sludge management and the Commonwealth’s growing wastewater PFAS database with sampling all 114 NPDES-permitted POTWs.

PFAS in wastewater influent, effluent, and sludge samples were characterized using EPA Methods 537M and 1633, the Total Oxidizable Precursor (TOP) assay, and EPA Method 1622 for adsorbable organic fluorine (AOF). Complementary targeted and non-targeted methods offer insight into PFAS profiles, oxidizable precursor compounds, and sludge sequestration, with important implications for data quality and source reduction.

Influent and effluent PFAS profiles were dominated by short-chain PFCAs, with comparable concentrations across facilities suggesting common, domestic sources. Sludge showed a distinct profile enriched in fluorotelomers and sulfonates and consistently exhibited the highest total PFAS concentrations. PFAS accumulation in sludge through sorption or biological activity was a dominant transport/transformation pathway. These findings indicate that sludges can be long-term PFAS reservoirs, complicating management given constrained disposal outlets across New England: Wastewater sludge management has become increasingly challenging as concerns over PFAS health impacts have grown and as available options have declined, driving up costs.

Effluent concentrations were generally comparable between targeted and TOP analyses, reflecting precursor oxidation during treatment. Influent and sludge showed higher precursor fractions, underscoring the potential value of TOP assays for these matrices. However, poor precursor conversion and inflated detection limits demonstrated the need for improved methods to better quantify PFAS mass flows in POTWs.

Industrial impacts were highly variable, with dischargers contributing 5% to 40% of influent PFAS mass loadings for some species, consistent with localized industrial use and reflecting industrial legacy and urbanization patterns. Some industries (e.g., landfill leachate, specialty manufacturers) also exhibited unique PFAS profiles, offering opportunities for forensic source attribution.

Nevertheless, PFAS characterization remains confounded by analytical and reporting challenges, including variability in duplicate samples and matrix-dependent reporting inconsistencies. These issues underscore the need for optimized analytical and reporting approaches along with strategic metadata collection to enable reliable quantification and meaningful cross-facility and interstate comparisons.

Effective PFAS management must incorporate upstream source reduction and industrial pretreatment complemented by the development of practical treatment technologies. Robust site characterization and harmonized analytical methods are critical to understanding PFAS fate and transport, supporting regulation, and guiding sustainable sludge management. As disposal options for sludge, septage, and leachate remain regionally constrained, MassDEP continues to develop an approach that considers regulatory, technical, economic, and logistical realities while protecting public health and water quality.

The Agency for Toxic Substances and Disease Registry (ATSDR) previously created the PFAS Blood Level Estimation Tool to estimate perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexanesulfonate (PFHxS) serum concentrations resulting from drinking PFAS contaminated water , calibrating model parameters for biological half-life (T½) and volume of distribution using Bayesian methods. Based on stakeholder feedback, we improved functionality to allow for batch processing, inclusion of multiple water concentrations and variable non-drinking water exposures through time, and changes in time-step calculations (mass vs. concentration). We also updated the breastfeeding pathway.

Using simulated exposures for individuals with known PFAS water and serum concentrations, we compared predicted serum PFAS concentrations resulting from each model change to both the measured and originally predicted serum levels. We then evaluated if these model changes, individually and combined, improved fit.

The original model accurately estimates serum levels for each PFAS for most adults, but somewhat overestimated serum concentrations for children. Results indicate that changes in moving PFAS mass rather than concentration to the next time-step improve model fit overall, particularly for children. Incorporating higher historic non-drinking water exposure, and changes to placental transfer assumptions had little change on overall prediction accuracy. Changing to an age independent volume of distribution resulted in slightly increased overestimates in children’s serum levels and was not implemented.

Preliminary results indicate updates to the ATDSR tool modestly improve serum PFAS predictions. However, remaining sources of uncertainties include accuracy in historical water concentrations, exposure from non-drinking water sources, and life-history characteristics of individuals.

Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of Abt, Texas A&M, CDC or ATSDR.

Developing effective soil management strategies to limit PFAS bioavailability in agricultural lands historically amended with PFAS-containing residuals is an important problem to solve, as grasses and other forages can transfer PFAS into livestock and ultimately humans.

This research investigates whether the incorporation of two carbon-based amendments—biochar and high carbon ash—into soil can reduce PFAS uptake in grasses and improve soil health in contaminated agricultural fields. The field trial is located in Maine on farmland heavily contaminated with PFAS due to historical applications of high PFAS-containing residuals. Both biochar and high carbon ash have sorptive properties; published research shows that biochar can immobilize PFAS compounds, and may reduce their bioavailability. In this research, field plots were established using a randomized block design with two amendment application rates. Plots were seeded with a grass mixture, and crop uptake of PFAS compounds is being monitored. Results from amended plots are compared to untreated controls. At present, complete data are available from one growing season, and monitoring is ongoing in a second season.

To complement the field trial, greenhouse experiments were conducted at Purdue University, using soils collected from the field site. The greenhouse trials tested high carbon ash applied at rates similar to the rates used in the field plots, and used the same grass seed mixture. Results from the greenhouse trials show statistically significant reductions in PFAS uptake in pots amended with high carbon ash compared to controls, indicating that sorption can reduce PFAS bioavailability under controlled conditions. In contrast, results from the field trial show minimal differences in PFAS uptake between amended and control plots, although additional data are still being collected and analyzed.

These findings suggest that biochar and high carbon ash have potential to immobilize PFAS in soils, but their effectiveness in the field may be constrained by factors such as soil moisture and amendment–soil interactions. The discrepancy between greenhouse and field outcomes highlights the need for long-term monitoring of the field plots and continued research. Ultimately, this work contributes to a better understanding of amendment-based remediation approaches and their potential role in remediating PFAS-contaminated soil.

Per- and polyfluoroalkyl substances (PFAS) have been a focus of public drinking water regulations in recent years. Policy makers at both the national and state levels have been seeking to identify which PFAS need to be prioritized and regulated in public drinking water. Part of this assessment involves reviewing occurrence data to determine frequency, geographic distribution, and concentration ranges for this class of compounds.

New York State began regulating perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) in public drinking water supplies in 2020. In addition to reporting PFOA and PFOS, over 2,000 (90%) public water systems have monitored for additional PFAS. The occurrence data for 29 PFAS collected over the past 5 years was analyzed. Several analyses were performed including frequency and spatial analysis of detections, co-occurrence, as well as a comparison of results to available benchmarks. In addition, PFAS occurrence data collected under the Environmental Protection Agency’s fifth Unregulated Contaminant Monitoring Rule (UCMR 5) was summarized. The frequency of detection analysis of the federal dataset was compared with the NYS regulatory dataset.

The results indicate that there is a difference in the frequency with which individual PFAS compounds occur, with an infrequent detection of certain PFAS compounds in public water systems. When PFAS compounds are detected in public water systems, they are rarely detected without the presence of PFOA and/or PFOS. The compound specific frequency of detection varied between datasets; however, the prevalence of certain individual compounds was consistent.

The occurrence within the class of PFAS can vary greatly and should be considered when discussing risk management decisions for public water systems. It is important to understand the limitations of any occurrence dataset when assessing the potential impact of proposed drinking water regulations, as the frequency of detections may differ. Co-occurrence of PFAS should continue to be discussed among policy makers as the data indicates regulation of PFOA and PFOS in public water systems is likely to capture the presence of other PFAS compounds.

Dietary intervention is considered an effective strategy to lower blood pressure (BP) and prevent hypertension. Diet is also a major exposure source to per- and polyfluoroalkyl substances (PFAS). Exposure to PFAS has been associated with elevated BP. However, few studies have assessed whether diet can modify the associations between PFAS and BP. We aim to examine the associations between PFAS and BP and how these associations vary by consumption of various types of food.

In 2021-2023, we enrolled adult participants (ages 18+) in Hyannis and Ayer, MA, in the Massachusetts PFAS and Your Health Study, part of the ATSDR Multi-site Study, a cross-sectional study on health effects of PFAS in communities in eight U.S. states. Participants (n=630) provided blood samples and completed body measurements and questionnaires about demographics, lifestyle, health conditions, and diet. Our food frequency questionnaire collected one-month consumption frequencies for specific foods previously associated with blood PFAS levels. Blood serum samples were analyzed for PFOA, PFOS, PFNA, PFHxS, PFDA, PFUnDA, and MeFOSAA. We used multivariable linear regression to assess associations of food consumption frequencies with serum PFAS, and of individual serum PFAS with systolic BP (SBP) and diastolic BP (DBP) in 423 participants not taking anti-hypertensive medications. Models were stratified by consumption frequencies of individual foods to assess effect modification, adjusting for age, sex, race and ethnicity, education, and body mass index.

Among the four most frequently detected PFAS, we found positive associations for dairy consumption with PFOS and PFNA, and for fish consumption with PFNA. Serum PFHxS, PFOS, and PFNA were positively associated with SBP and DBP. Each doubling of serum PFOS was associated with 1.3 mmHg (95% CI: 0.1, 2.4) and 1.4 mmHg (0.5, 2.2) increases in SBP and DBP, respectively. The associations of PFAS with SBP or DBP vary by consumption frequency of certain types of foods. We found stronger associations among participants who consumed dairy, fast food, or store-bought fish more frequently. For instance, each doubling of PFOS was associated with a 2.3 mmHg (0.2, 4.4) increase in DBP among participants who consumed fast food >once/week, compared to a 0.3 mmHg (-1.0, 1.5) change among participants who never consumed fast food. By contrast, we observed stronger associations between PFAS and BP among participants who never consumed beans or soy compared to those who reported consuming these foods. For instance, each doubling of PFOS was associated with a 3.6 mmHg (0.9, 6.3) increase in DBP among participants who never consumed beans, compared to a 0.9 mmHg (-0.3, 2.2) change among participants who consumed beans >once/week.

Ours is the first analysis to demonstrate that PFAS-BP associations can vary by consumption of certain types of foods. These differences may be due to a combination of factors, including associations of certain foods with chronic inflammation and with serum PFAS. Given the importance of dietary interventions to prevent hypertension, more longitudinal research is needed to fully understand the interactions among diet, PFAS, and cardiometabolic health.

Per- and polyfluoroalkyl substances (PFAS) in agricultural soils pose a serious threat to food safety, environmental quality, and farm livelihoods. Compounds such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), and perfluorobutanoic acid (PFBA) are highly persistent and resist natural breakdown. Crops like lettuce and tomato can accumulate PFAS and transform precursors, leading to dietary exposure through edible tissues. In Maine, over 50 farms have been impacted by past applications of PFAS-contaminated biosolids, resulting in production losses, farmer uncertainty, and urgent regulatory concern. There is a clear need for remediation strategies that are cost-effective and practical for field use.

Our research investigates the use of woody biochar as a soil amendment to adsorb PFAS and reduce their mobility and uptake by plants. While biochar has shown promise for PFAS sorption, most studies have been limited to controlled lab conditions, and its field performance remains uncertain. To address this gap, we conducted a pot study at UMaine Extension’s greenhouse and a field study at Hunter Farm, Unity, Maine, in 2023. Adding biochar at 30% by volume to PFAS-contaminated soil stabilized all PFAS types and reduced their uptake, particularly long-chain compounds, in both lettuce leaves and tomato fruits. Lettuce accumulated higher concentrations and a broader spectrum of PFAS than tomato.

In summer 2025, we conducted a field study to assess the effect of biochar aging on PFAS uptake. We also conducted a greenhouse pot study to develop a predictive model for optimal biochar application rates based on soil PFAS levels. The field-applied biochar had been in soil for nearly two years, likely undergoing chemical and physical changes—such as surface oxidation and formation of functional groups—that may influence PFAS sorption. Lettuce and tomato were grown again for comparison. We hypothesize that (1) aged biochar will exhibit enhanced PFAS sorption due to chemical and physical changes, and (2) higher application rates will result in greater PFAS stabilization and reduced crop uptake.

In the pot study, PFBA and PFBS were spiked into the soil at 100 ppb, then treated with biochar at 0% (control), 5%, 10%, and 15% by volume. The biotransformation of the PFOS precursor, N-ethyl perfluorooctane sulfonamidoacetic acid (NEtPFOSAA), in lettuce was also studied by spiking PFOS and/or NEtPFOSAA at 10 ppb into the soil/biochar mixture. Soil, leachate, and plant tissues will be collected at harvest. PFAS concentrations will be measured using high-sensitivity liquid chromatography–mass spectrometry (LC-MS) at Brown University. Data will be evaluated with ANOVA and regression to test the effects of biochar aging, application rate, and their interaction.

At the conference, we will present results showing how biochar aging alters PFAS retention, how application rate affects crop uptake, and how responses differ between lettuce and tomato. These findings will help define when and how biochar should be applied in PFAS-contaminated soils and highlight key trade-offs for field deployment. This represents one of the first studies to directly evaluate biochar aging under real agricultural conditions in Maine and provides actionable insights for farmers, regulators, and remediation professionals.

In 2023, the Vermont Department of Environmental Conservation initiated a two-phase project aimed at quantifying and characterizing PFAS in the wastewater of all municipal POTWs in Vermont and identifying areas for source reduction. Phase I involved one year of quarterly sampling and analysis via modified EPA Method 537.1 and total oxidizable precursor assay (TOPA). Results from Phase I identified seasonal variability in total PFAS mass discharged in effluent. Total PFAS discharged as measured via target analysis was significantly greater in the summer, perhaps as a result of increased biological degradation of precursor PFAS during warmer months. Phase I data allowed for calculation of mass loading in influent and effluent, and mass discharge rates in effluent on a community and per capita basis across the state. Information generated during Phase I was used to develop a ranking matrix for identifying communities for target sampling in Phase II. Phase II will be complete in 2025 and involves assessment of PFAS loading to POTWs in upstream sewersheds with varying potential sources of PFAS.  This information has provided valued insight for targeted source reduction in these communities. This presentation summarizes the collection approach, the data analysis approach, and key findings from the two-phase study.

Since the early 2000s, industries have shifted away from the more studied long-chain PFAS toward replacement and alternative PFAS, with poorly characterized health effects. An industrial polymer manufacturing facility in New Jersey used a perfluorononanoic acid (PFNA)-based processing aid to produce polyvinylidene fluoride. Starting in 1996, a mixture of chloroperfluoropolyether carboxylates (ClPFPECAs) was used concurrently in limited amounts until the PFNA-mixture was phased out in 2010, after which ClPFPECA use substantially increased. ClPFPECAs were used until the facility ceased use of fluorosurfactants in 2021. To our knowledge, these compounds have only been used at facilities in New Jersey and Italy. Among exposed Italian workers, ClPFPECAs had a half-life similar to that of perfluorooctanoic acid (PFOA) and were associated with increased serum lipids and other health biomarkers. No human biomonitoring or health effects studies have examined ClPFPECAs in US populations. This study investigated plasma ClPFPECA concentrations and their association with serum lipid levels among residents of a community neighboring the New Jersey facility, whose drinking water was historically contaminated with PFAS.

In this cross-sectional study, six ClPFPECA congeners (denoted by their number of ethyl and propyl [e,p] groups: 0,1; 0,2; 1,1; 1,2; 0,3; and 0,4) were quantified in plasma using LC-MS/MS from a convenience sample of current and former adult residents. This analysis was restricted to 499 participants not taking lipid-lowering medications. Single pollutant multivariable linear regression models assessed associations between ln-transformed congener concentrations and total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and non-HDL cholesterol, adjusting for sex, age, race-ethnicity, body-mass index, education, household income, cigarette usage, and alcohol consumption. Bayesian kernel machine regression (BKMR) assessed PFAS mixture effects incorporating ClPFPECA-0,1, ClPFPECA-0,2, PFOA, PFOS, PFNA, and PFHxS.

The mean age of participants was 44.5 years; the majority were female (63%), non-Hispanic Black (66%), and low-income. Only two congeners – 0,1 and 0,2 – were detected in >85% of samples (median concentrations 0.045 and 0.010 ng/mL, respectively); the remaining congeners were detected in <7% of samples and excluded from further analysis. In adjusted single pollutant models, both congeners showed consistent positive associations with TC, LDL-C, HDL-C, and non-HDL, and inverse associations with TG. Associations were statistically significant for ClPFPECA-0,1 with TC, LDL-C, and HDL-C, and for ClPFPECA-0,2 with HDL-C and TG. In BKMR, the overall PFAS mixture was positively associated with TC, LDL-C, and non-HDL at higher exposure quantiles, with diluted posterior inclusion probabilities (PIPs) suggesting a shared mixture signal. The dominant drivers for associations with HDL-C and TG were ClPFPECA-0,1 (PIP=0.47) and ClPFPECA-0,2 (PIP=0.63), respectively.

ClPFPECAs were detectable in community residents and associated with altered lipid profiles at very low plasma concentrations. To our knowledge, this is the first study to investigate ClPFPECA health effects in a non-occupationally exposed population, underscoring the need for additional research and continued surveillance of alternative PFAS – particularly in environmental justice communities.

High exposure to per- and polyfluoroalkyl substances (PFAS) has been linked to an increased risk of kidney and testicular cancers. The International Agency for Research on Cancer has recently classified PFOA as a Group 1: carcinogenic to humans, and PFOS as a Group 2B: possibly carcinogenic to humans. Despite growing concerns, there's a lack of data on PFAS levels in human tissues, especially in cancer tumors. The extent of PFAS bioaccumulation in human tissues and their role in cancer development are still poorly understood. This study examines PFAS presence and levels in surgical tumor tissues from firefighters with cancer, providing direct evidence of the presence of PFAS tumors.

Tumor samples from five firefighters (one kidney and four thyroid tumors) with cancer were collected at Vincere Cancer Center in Scottsdale, Arizona, and shipped on dry ice. For analysis, a portion of the tissue was spiked with PFAS internal standards, ground, and processed through solid phase extraction for analysis. Both targeted and untargeted PFAS analyses were performed. A list of 47 PFAS compounds was quantified using LC-ESI-MS/MS for targeted analysis. Additionally, an untargeted analysis was employed using LC-HR-QTOF-MS/MS and MSDial software against a PFAS library of approximately 7,000 compounds. Total organic fluorine was measured using combustion ion chromatography.

All tumor samples contained 2 to 6 PFAS species, with concentrations ranging from 99.3ng/g to 920.2 ng/g. The highest concentration was PFOA (361.71 ng/g), followed by PFBS (286.13 ng/g) and PFPrA (225.99 ng/g). Other common PFAS included PFHxA, PFBA, PFPrS, and PFHpA. Untargeted analysis identified 12 to 20 PFAS species per sample, including those from the targeted analysis, many with high confidence. Ultrashort-chain PFAS such as TFA and PFPrA, along with fluorotelomer ethers, were detected at moderate levels. PFBA, PFHxA, PFOA, PFOS, and PFDS were present in all samples. Perfluoro keto and peroxidized compounds were also identified. Total organic fluorine from the targeted analysis ranged from 0.01% to 9% of the total organic fluorine in the tissue.

This study highlights the widespread presence of PFAS in tumor tissues of cancer patients, with concentrations exceeding national averages. These findings emphasize the need for further research into health risks associated with PFAS exposure, especially ultra-short-chain PFAS, whose toxicological profiles remain largely unexplored.

Reconstructing substance release, including estimating when a release occurred and/or when impacts from those releases first reached groundwater is critical for source identification and cost allocation among potentially responsible parties. For per- and polyfluoroalkyl substances (PFAS), this requires understanding their retention and transport in the vadose zone (i.e., unsaturated zone), which can be a long-term source of some PFAS to groundwater, with impacts potentially occurring over several years or decades following their initial release(s).

In this study, we used an advanced numerical modeling approach to estimate the timing of PFAS migration from surface soils to groundwater at a site with documented historical PFAS releases dating back to early 1980s. Using site-specific geologic and hydrogeochemical data, we constructed transient flow and transport models (HYDRUS-1D coupled with USGS MODFLOW/MT3DMS) to simulate vertical migration of select PFAS through a 1.1-acre sandy source area where surface soils currently contain up to 1 mg/kg of the primary legacy PFAS. Additionally, we conducted sensitivity analyses to identify the input parameters that most strongly influence the estimation of travel times for select PFAS.

Model results indicated that groundwater beneath the source area exceeded state regulatory limits for the primary legacy PFAS within 10 years of the initial release. Within the following decade, predicted concentrations increased to tens of thousands of nanograms per liter (ng/L), consistent with the levels measured in groundwater today. The simulations predicted a vertical migration rate of the primary legacy PFAS through the vadose zone at approximately 2 feet/year.

The model was calibrated against long-term average concentrations (2014-2024) of the primary legacy PFAS, measured in two monitoring wells in the vicinity and immediately downgradient of the source area. Calibrated model parameters, including hydraulic conductivity, dispersivity, recharge rate, and partition coefficients of the primary legacy PFAS at the solid–water and air–water interfaces were within the range of measured site-specific values and literature data. Sensitivity analysis identified the organic carbon–water partition coefficient (Koc) as the most influential parameter, emphasizing the need to constrain Koc for reliable PFAS transport predictions in unsaturated systems. Air–water partitioning affected the retention of the primary legacy PFAS in the vadose zone but played a less significant role compared to organic carbon partitioning.

Several key limitations of this modeling effort should be noted: (i) the simulations did not account for the potential competitive adsorption of PFAS mixtures or interactions with other hydrocarbon surfactants/co-solvents, which could influence PFAS retention and transport; (ii) there are uncertainties in reconstructing time-varying source concentrations in surface soils, and (iii) the model did not account for potential precursor transformations through biotic or abiotic processes that could alter the composition of PFAS and their mobility in groundwater. Despite these constraints, the study demonstrates a robust framework for estimating release-to-impact timelines for select PFAS and provides insight into the factors that influence transport of PFAS in the vadose-zone.

Per- and polyfluoroalkyl substances (PFAS) are used in construction materials including paints, varnishes, adhesives, and coatings. However, little is known about their use, workplace exposures, or body burden in construction workers. This study aimed to characterize PFAS exposure in two groups of construction workers through product analysis and urinary biomonitoring.

We recruited 72 industrial painters and spray polyurethane foam (SPF) insulation workers from 28 construction sites in Massachusetts. Participants provided matched pre- and post-shift urine samples. All urine samples (n=144) and nine construction products were analyzed for 30 PFAS compounds using liquid chromatography–electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Field observations documented tasks, products, personal protective equipment (PPE) use, and site conditions. This work was conducted as part of a larger study focused on assessing occupational exposures to reactive chemical systems in construction.

Bulk product analysis identified three short-chain PFAS at varying concentrations, PFBuS (293 µg/g), PFBuA (16.6 µg/g), and GenX (5.0 µg/g); none disclosed in product safety data sheets. Urinary biomonitoring detected nine PFAS: five short-chain (PFBuA, PFBuS, PFPeS, PFHxA, GenX) and two ultra short-chain compounds (PFPrA, PFPrS) were present in >80% of samples. Long-chain PFAS (PFOA, PFOS, PFNA) were not detected in the tested products and urine samples. Urinary concentrations of ultra-short-chain PFAS exceeded those of short-chain species. PFBuA levels were significantly higher in SPF workers than in coating workers (p < 0.05), consistent with its presence in SPF products. Among coating workers, PFPrS and NBP2 increased significantly post-shift (p < 0.05). Urinary concentrations of ultra-short-chain PFAS in coating workers were up to 100 times higher than previously reported in the general population.

This study demonstrates that occupational exposures contribute to PFAS body burden among SPF and coating workers. Our findings underscore the need for expanded biomonitoring efforts, including serum PFAS assessment, as well as identification of critical exposure sources and pathways to guide strategies that protect worker health in the construction industry.

Since 2016, NHDES has requested contaminated sites to assess the potential for PFAS to have impacted groundwater quality, and now, approximately ten years later, the NHDES Hazardous Waste Remediation Bureau (HWRB) actively oversees varying phases of characterization, monitoring, and remediation at more than 550 PFAS contaminated sites. This presentation will discuss the sources of contamination, the range of contaminants detected and the significance of the impacts to groundwater and other media, observed trends where available, remedial progress, and regulatory changes.

Although the first major PFAS discovery in NH was associated with the Pease Air Force Base in 2014, it was the discovery of contamination from an industrial facility in 2016 that rapidly spurred investigation in the following years into the potential for groundwater contamination at existing contaminated sites and landfills throughout the state.

Currently, more than 96 percent of the active state-listed hazardous waste, CERCLA and Brownfields sites that have sampled have detected PFAS in groundwater samples, and of those sites, nearly 80 percent have PFAS at levels greater than the applicable Ambient Groundwater Quality Standards (AGQS). Similarly, more than 90 percent of the unlined and/or lined solid waste disposal facilities and synthetic lined wastewater treatment lagoons managed by HWRB have detected PFAS in groundwater samples, and of those sites, nearly 75 percent have PFAS at levels greater than the applicable AGQS. New sites continue to be identified.

The sources of groundwater contamination at HWRB sites include, but are not limited to: applications of class B foam (e.g., aqueous film forming foam [AFFF]), manufacturing of textiles and paper, metal working and plating, waste management facilities (e.g., landfills), discharges of commercial wastewater, car washes, dry cleaners, scrap and metal recycling facilities, semi-conductor manufacturing, and use of consumer products, as well as a significant number of unknown (yet to be confirmed) and mixed sources. PFAS are not the only regulated contaminants detected, as other contaminants of concern are also present in groundwater at many of these sites.

New Hampshire’s regulatory landscape for PFAS has evolved over the past ten years: from establishment of PFAS AGQS in 2016 with subsequent reduction in the AGQS values in 2019/2020;  development of direct contact soil screening values in 2018, evaluation of occurrence in shallow soil and leaching potential in 2021/2022 and promulgation of PFAS Soil Remediation Standards (SRS) that incorporate groundwater protection in 2024; and publication of surface water standards in 2025. These changes have influenced the progress of assessment and remediation at these sites, prompting evaluation and risk assessment for additional matrices, including soil, sediment, surface water, stormwater, and fish tissue.

Firefighters may experience firefighting and non-firefighting related PFAS exposures. Exposure to certain PFAS compounds has been associated with a host of adverse human health outcomes, including changes to lipid concentrations such as elevated total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Healthy lipid profiles are critical to cardiovascular health, particularly for firefighters. Firefighters experience one of the highest risks of job-related cardiovascular deaths of all U.S. occupations. While volunteer firefighters make up a majority of the U.S. fire service (65%), and may have unique PFAS exposure profiles, the associations between their PFAS exposures and serum lipid profiles have not been well studied. We aimed to assess the associations between serum lipid measures and serum PFAS concentrations in a large study of U.S. volunteer firefighters.

Seven lipid measures and 12 PFAS were quantified in serum of volunteer firefighters from 9 U.S. states enrolled in the Cancer Assessment and Prevention Study (CAPS). Participants under age 50 were included in primary analyses (n = 354). Possible confounders were obtained from surveys administered at study enrollment and included age, sex, alcohol use, income, primary occupation, monthly fire calls, and firefighting tasks. We used linear mixed models to assess the association between each lipid measure and each log2-transformed PFAS, adjusted for covariates. Fire department region was included as a random effect. We also assessed the combined effects of 6 PFAS with high detection frequencies (>70%) using Bayesian Kernel Machine Regression (BKMR) and quantile g-computation (q-g-comp).

In this majority non-Hispanic White (87%), male (85%) cohort under age 50, between 21-51% had TC, LDL-C, high density lipoprotein (HDL-C), triglycerides (TG), non-HDL-C, VLDL-C, or TC: HDL-C ratio outside of the clinically recommended range.  PFOA, PFOS, PFNA, PFHxS, PFDA, and PFUnDA were detected in >70% of participants. PFOS was the compound with the highest average concentration (geometric mean: 2.50 ng/mL). MeFOSAA, PFHpA, FOSA, PFBS, PFDoDA, and EtFOSAA were detected in <50% of participants.

PFOA, PFOS, PFNA, PFHxS, and PFDA were positively associated with TC, LDL-C, triglycerides (TG), and non-HDL-C in single pollutant models. For example, a doubling in serum PFOA was associated with a 6.19 mg/dL (95% CI: 1.69 – 10.68) increase in TC. Associations between these compounds and HDL-C, VLDL-C and TC: HDL, as well as associations between the less frequently detected PFAS compounds and all lipid measures, tended to be of a lower magnitude and less precise. Mixture model results were generally consistent with the results of single-pollutant models.

Serum concentrations of PFOA, PFOS, PFNA, PFHxS, and PFDA were positively associated with adverse lipid profiles in this cross-sectional study of U.S. volunteer firefighters. These findings are broadly consistent with studies of other occupational and general populations. Our study adds to the literature by including additional clinically relevant lipid measures and less frequently studied PFAS compounds. Ongoing follow-up with this cohort will be important to understand the potential impact of exposures of concern. Tailored interventions to reduce PFAS exposure and improve cardiometabolic health in this public service population may be needed.

Co-authors and affiliations:

• Abigail Bline, Maine Center for Disease Control and Prevention
• Rebecca DeVries, Eastern Research Group
• Naida Gavrelis, Eastern Research Group
• Philippe Grandjean, University of Southern Denmark
• Emily Heckel, Silent Spring Institute
• Marlee R. Quinn, Harvard T.H. Chan School of Public Health
• Mary Beth Terry, Silent Spring Institute
• Tamarra James-Todd, Harvard T.H. Chan School of Public Health
• Laurel Schaider, Silent Spring Institute

The year 2026 marks 10 years since discovery of releases associated with the former Saint-Gobain Performance Plastics facility in Merrimack, NH. The detection of per- and polyfluoroalkyl substances (PFAS) in water samples collected by Saint-Gobain from the Merrimack Village District public water system prompted NHDES to immediately initiate an investigation into the source and extent of PFAS contamination. Early in the investigation it became apparent that airborne transport of PFAS from the Saint-Gobain facility was an important pathway for regional groundwater contamination in several of the surrounding towns. A major effort to sample water supply wells, both public and private, expanded outward from the facility into the surrounding communities.

The scope of the drinking water sampling effort, including the identification of supply wells at risk and provision of alternate water, has morphed over time based on the changing regulatory framework of these contaminants. Initial sampling in 2016 was guided based on the US EPA long-term health advisory level for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) of 70 parts per trillion (ppt), which was adopted by NHDES under emergency rulemaking as an enforceable Ambient Groundwater Quality Standard (AGQS). By 2018, numerous water supply wells had been identified that exceeded the 70 ppt AGQS, with many impacted residences being connected to public water. In March 2018, NHDES and Saint-Gobain entered into a Consent Decree that identified an area encompassing the wells that exceeded 70 ppt and formalized a path forward to provide additional impacted well owners with a permanent remedy. The Consent Decree also established an “Outer Boundary” for investigation that consisted of a 65 square mile area encompassing portions of six municipalities.

As ever-changing science on these contaminants continued to be reviewed and evaluated, the state AGQS and MCLs for PFAS were updated in September 2019. The update lowered the AGQS for PFOA to 12 ppt and resulted in the need for expanded drinking water monitoring and additional alternate water remedies within the Outer Boundary of the 2018 Consent Decree. Since 2019, Saint-Gobain has been identifying and sampling water supply wells potentially at risk of contamination from Saint-Gobain’s releases. This effort has included the collection of drinking water samples from approximately 2,600 properties and ongoing monitoring to evaluate fluctuations in contaminant concentrations and support the establishment of a groundwater management zone and groundwater management permit. As drinking water samples are collected and exceedances of state standards are observed, Saint-Gobain continues to provide bottled water as an interim measure and propose permanent alternate water remedies. In total, nearly 900 properties have been designated for POETs and more than 1,100 properties for municipal water service connections across the six municipalities.

This presentation will cover an overview of the Saint-Gobain project, touching upon NHDES response efforts, investigation and work completed by Saint-Gobain and NHDES, stakeholder involvement through the process, current status of the project, changes to the regulatory framework during the 10 years of project activity, impacts to other NHDES programs and initiatives, and lessons learned.

While EPA and other federal agencies have undertaken regulatory actions ranging from establishing drinking water standards for PFAS to requiring PFAS reporting, EPA is reconsidering several regulations in light of legal or practical challenges.  In response, states are increasingly taking the lead in identifying contaminated resources (e.g., drinking water, fish tissue, and surface waters) and implementing measures to reduce PFAS exposures.

A growing number of states are targeting PFAS in products—from cosmetics to textiles—as part of broader efforts to protect public health, safeguard environmental quality, and reduce long-term remediation costs. To date, there are approximately 13 states with 35 proposed laws and 18 states with approximately 50 enacted laws that seek to ban or manage products containing PFAS.

As a leading provider of technical and policy support to states grappling with a range of PFAS issues, including through support of NEWMOA’s Interstate Chemicals Clearinghouse (IC2) High Priority Chemical Data Reporting System, ERG offers valuable insights into strategies for addressing exposures to PFAS in consumer and other products.  This presentation will cover the ABCs of state actions on PFAS in products, including:

• Approaches: States are considering or employing a variety of approaches to regulate or address exposures to intentionally added PFAS in products. Methods can include prohibiting the sale or distribution of products containing PFAS, communicating the health and environmental impacts of PFAS found in products, labeling products to communicate PFAS content or absence, requiring testing and reporting on products containing PFAS, or some combination of all of these approaches.
• Building Blocks: Building blocks for state solutions include: how best to obtain stakeholder buy in; what products to consider for prohibition, exemption, or regulation; understanding of primary and secondary audiences for product labels or public education campaigns; what chemical/product information the state would want to collect if they adopt reporting requirements; and reporting system design.
• Collaboration: States may have opportunities to collaborate to improve outcomes. For example, states may agree to accept designations made by other states related to unavoidable uses of PFAS in certain products. They may also engage in data sharing related to certain reporting requirements. This type of collaboration may reduce burden both on the responsible parties engaged in reporting and on state departments that must process and review the submitted information.

Through this presentation, attendees will learn about emerging state strategies for PFAS in products and the foundational elements needed to support effective state programs.

Part 1 presented RSVRA site characterization and fate and transport of AFFF-derived PFAS in the overburden, including the distribution of PFAS compounds in different source areas. Part 2 first creates a 3D conceptual site model (CSM) for the FRA by integrating physical and chemical characterization techniques and then incorporates the spatial and temporal variability and transformation of PFAS compounds into this framework.

The RSVRA sits on a broad plateau of intermediate elevation (238m) between the higher Green Mountains (730m+) to the east and the lower Otter Creek valley (165m) to the west. This plateau is underlain by Cambrian dolomitic rocks that were folded into a map-scale anticline-syncline pair dissected by ~E-W fractures zones and separated from the siliceous mountains (east) and mixed carbonate and siliceous valley (west) by faults. Groundwater recharge in the Green Mountains is defined as distal and on the RSVRA plateau as local. Artificial fill and Pleistocene till overlie bedrock on the RSVRA plateau. Bedrock outcrops are common around the RSVRA indicating a surficial aquifer of variable thickness and extent over the FRA.

By plotting recharge ages (CFC11, CFC12, CFC113) vs. alkalinity for wells and springs, there are 3 distinct groundwater groups: 1) Green Mt. Distal Recharge- low alkalinity (70-120 ppm), recharge ages 45-60+ years, and non-detect (nd) total regulated PFAS (< 2 ppt); 2) Old Local Recharge- high alkalinity (275-315 ppm), recharge ages 50-55 years, and PFAS 5-49 ppt; and 3) Young Local Recharge- high alkalinity (214-382 ppm), recharge ages 30-40 years, and PFAS nd-607 ppt.

Group 1 groundwater represents distal recharge into siliceous rocks of the Green Mts. with long residence times and flow paths to the FRA in the southeastern area of the RSVRA plateau, with one isolated well to the NW. Group 2 groundwater was recharged locally into carbonates of the RSVRA plateau prior to and synchronous with the early stages of PFAS application and is only found on the western side of the airport. Group 3 groundwater was also locally recharged during the main phase of PFAS testing and occurs in wells between groups 1 and 2.

Wells closest to the AFFF testing site exhibit 90-270 ng/L (ppt) 6:2 fluorotelomer sulfonates (FTS) whereas downgradient wells have no detectable FTS and are dominated by perfluorocarboxylic acids (PFCAs). Shorter-chain perfluorohexanoic acid (PFHxA) and perfluoropentanoic acid (PFPeA) are prevalent in wells closer to the AFFF source while longer-chain perfluorooctanoic acid (PFOA) is prevalent in distal wells. Temporal variability (2018-2024) is indicated by changing PFAS ratios over time, which is especially evident in wells closest to the AFFF source where decreasing 6:2 FTS occurs in conjunction with increasing PFHxA and PFPeA over time. This statistically significant trend is consistent with transformation of 6:2 FTS to PFHxA and PFPeA in groundwater. The map and cross sections in the CSM indicate that folding and fracturing of the RSVRA ridge strongly influenced groundwater flow, and the distribution and transformation of PFAS compounds over time.

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants that bioaccumulate in aquatic ecosystems, raising major concerns for food safety and coastal economies reliant on seafood. On August 19, 2024, approximately 1,450 gallons of PFAS-laden aqueous film-forming foam (AFFF) spilled from the former Brunswick Naval Air Station into watersheds draining into Harpswell Cove, Maine. This cove supports valuable shellfish harvesting and aquaculture activities, and the spill has heightened concern among harvesters, regulators, and consumers about the safety and marketability of seafood. In Maine alone, the shellfish industry contributes hundreds of millions of dollars annually to the state’s economy, and contamination events can trigger fishery closures, consumer advisories, and long-term economic disruption.

This study tracks the spatiotemporal fate and impact of the spill by characterizing PFAS types and levels (ng/g) in sediments and six seafood species (hard shell clam, soft shell clam, green crab, golden mussel, oyster, and blue mussel) sampled at three sites over eight time points (October 2024–June 2025). Predictive models are being developed to link PFAS occurrence with spatial and temporal drivers, while multi-objective optimization evaluates remediation scenarios. By integrating field sampling with these advanced analytics, this study provides post-spill PFAS assessments in seafood-dependent coastal ecosystems, supporting both public health and economic resilience.

In 2025, the Toxics in Packaging Clearinghouse (TPCH) and the Interstate Chemical Clearinghouse (IC2) partnered to host a series of workgroup meetings on state regulation of PFAS in Packaging. In the wake of several states passing laws or considering them to ban the use of PFAS in food-contact packaging, this group of state regulators met to discuss topics such as: What does testing for PFAS in packaging look like without a national standard? How does a manufacturer demonstrate compliance with "no intentionally added" PFAS? Are there third party certifications that could help demonstrate compliance? Are domestic or foreign packaging manufacturers already phasing out their use?  This session will cover the findings of the workgroup, and propose the next questions to answer in the regulation of PFAS in food packaging.

Many areas across New England have been impacted by the presence of aqueous film-forming foams (AFFF) containing per- and polyfluoroalkyl substances (PFAS), historically applied during firefighting activities. These applications have resulted in persistent groundwater contamination and the formation of extensive subsurface plumes. Predicting the fate and transport of PFAS in these environments is essential for mitigating risks associated with exposure to contaminated soil and groundwater. While numerous studies have investigated PFAS behavior in both laboratory settings and field sites, there remains a significant gap in understanding the specific interfacial interactions between PFAS compound, and particularly perfluorooctanesulfonic acid (PFOS) and soils. Sorption processes play a critical role in reactive transport, as the partitioning of PFAS to the solid phase strongly influences their mobility in the saturated zone. These interactions are highly sensitive to site-specific geochemical conditions, making their accurate representation essential for reliable transport modeling. Incorporating these processes into reactive transport models is crucial for improving the predictive accuracy of PFAS fate and transport in subsurface environments. This presentation will highlight key insights into PFAS reactive transport based on two primary study areas: Killingworth, Connecticut, and the tanker truck rollover site in Cape Cod, Massachusetts. These investigations provide a deeper understanding of PFAS mobility under variable field conditions and inform more effective modeling and remediation strategies.

PART 1: 

The County of Barnstable (County) and GZA will present a case study of the County’s historical and recent PFAS investigation and remediation efforts at the County’s former municipal fire training facility (MFTF) in Hyannis, Massachusetts.

The MFTF site was operated as a fire training facility for municipal fire departments throughout Cape Cod, as well as other first responders.  When operational, PFAS-containing aqueous fire-fighting foam (AFFF) was released to the environment during these training activities, resulting in residual contaminated soil, groundwater, surface water, and sediments. The use of AFFF was discontinued at the site by approximately 2015, and fire training activities, including water training activities, ceased in 2019.

The site is located on approximately 70 feet of Barnstable glacial outwash plain deposits and along the eastern shore of Flintrock Pond. There are 10 municipal water supply wells located within approximately 1.3 miles of the site. PFAS constituents were first detected in the hydraulically downgradient water supply wells in 2014. In addition to the MFTF, there are multiple other known or potential PFAS sources in the vicinity of the site. The site is classified as Tier I, pursuant to the Massachusetts Contingency Plan (MCP).

This presentation will focus on the detailed hydrogeologic investigations and initial response actions that the County has performed, including:

• Development of an external stakeholders working group to foster improved and efficient data sharing and collaboration;
• Hydrogeologic site investigations and characterization;
• Numerical groundwater flow modeling;
• Forensic data analyses to identify the source and travel pathways of multiple PFAS plumes; and
• Ecological risk assessment.

Based on the findings of our work, a permeable reactive barrier (PRB) was selected as an appropriate remedial measure to limit further PFAS migration from the site.  Between 2024 and 2025, a PRB pilot-test and subsequent full-scale PRB injection utilizing colloidal activated carbon (CAC) was performed as an Immediate Response Action (IRA) pursuant to the requirements of the MCP.  The design and implementation of the pilot- and full-scale PRB will be discussed in Part 2.

PART 2:

The County of Barnstable (County), GZA, and Regenesis will be pleased to co-present the second part of a very interesting case study of the County’s investigation and remediation efforts at the County’s former municipal fire training facility (MFTF) in Hyannis, Massachusetts.  Part 1 of this presentation will focus on the County’s investigation and remedial planning efforts.  This second part of our presentation strategy will focus on the County’s selection, design, pilot testing and full scale implementation of a permeable Reactive Barrier to limit further migration of PFAS-impacted groundwater from the MFTF site.

The site is located on approximately 70 feet of Barnstable glacial outwash plain deposits and located along the eastern shore of Flintrock Pond.  There are 10 municipal water supply wells located within __ miles of the site.  PFAS constituents were first detected in the hydraulically downgradient water supply wells in 2015.  The site is classified as Tier I disposal site, pursuant to the Massachusetts Contingency Plan (MCP).  The municipal water supply is currently treated for PFAS removal using granular activated carbon.

Residual impacted groundwater exists at the site at PFAS6 concentrations up to 341,400 ng/l.  To mitigate further contaminant migration from the site towards the down-gradient municipal water supply wells, a Permeable Reactive Barrier (PRB) was selected as an appropriate remedial measure.  The PRB, combined with a surface cap installed over the impacted areas of the MFTF, is expected to significantly contain PFAS6 constituents in the vicinity of the site, thus improving future downgradient groundwater quality at the municipal water supply wells.

In 2024, GZA and Regenesis initiated a PRB pilot-test to verify the effectiveness of a PRB by injecting colloidal activated carbon (CAC) into the subsurface.  The pilot test also allowed for assessing constructability information for the full-scale implementation.  In 2025, based on positive initial pilot test results, a full-scale CAC PRB was injected along the hydraulically downgradient property line of the MFTF as an Immediate Response Action (IRA) pursuant to the requirements of the MCP.

By July 1st 2026, any manufacturer selling a product containing PFAS into the state of Minnesota must report required information to the state through the new PFAS Reporting Information System for Manufacturers (PRISM). The Minnesota Pollution Control Agency (MPCA) has contracted with ERG and NEWMOA to create the PRISM system to accept the required information from manufacturers to satisfy the reporting requirements set forth in Minnesota's Products Containing PFAS law, now know as Amara's law. This session will provide a brief overview of the reporting requirements of Amara's law, showcase the reporting systems functionality, and what data the public can access once reports are published.

The North Carolina Department of Environmental Quality (NCDEQ) has expanded its analytical capabilities to address both legacy and emerging per- and polyfluoroalkyl substances (PFAS), including perfluoroether carboxylic acids (PFECAs). This presentation outlines the laboratory’s current targeted LC-MS/MS workflows for quantifying PFAS in environmental matrices, with a focus on method performance, compound-specific recovery, and matrix interferences.

A case study will be presented detailing the occurrence and enrichment of PFAS in surface water foam collected from impacted freshwater systems. Analytical results demonstrate significant partitioning of PFAS into foam, with concentration factors exceeding those in the underlying water by several orders of magnitude. These findings have implications for environmental fate modeling and risk assessment.

We will also highlight a collaborative study with the U.S. Environmental Protection Agency aimed at harmonizing analytical protocols and evaluating inter-laboratory reproducibility for PFAS quantitation in complex matrices. Additionally, preliminary results from in-lab foam fractionation experiments will be discussed, exploring the selective removal of PFAS via aeration and skimming. These experiments provide insight into the physicochemical drivers of PFAS behavior at air–water interfaces and their potential application in passive remediation strategies.

This work underscores the importance of integrated analytical, field, and experimental approaches to better understand PFAS distribution and inform mitigation strategies.

Growing concern over the ubiquity of per- and poly-fluorinated alkyl substances (PFAS) in environmental media and growing evidence of adverse human health and ecological effects from this family of chemicals is driving the need to identify effective PFAS remediation and destruction technologies. Due to the strength of multiple carbon-fluorine (C-F) chemical bonds in these compounds, many PFAS are difficult to degrade, both in-situ by either normal environmental degradation pathways or in-situ treatment technologies, or ex-situ by various treatment technologies. Although they share the common characteristic of multiple C-F bonds, the PFAS category contains thousands of different chemical species. This makes RCRA permitted thermal destruction proven technology for eliminating “environmentally terminal” (not easily degraded further in the environment) PFAS chemicals.

Clean Harbors Environmental Services (CHES) is the leading provider of hazardous waste treatment and disposal services in North America and operates ten hazardous waste combustors (HWCs) at five locations.

CHES recently completed the third full-scale PFAS destruction testing at its HWC in Aragonite, Utah collaborating with EPA ORD and DoD SERPD. CHES previously completed testing in 2021 and 2022.

The testing included feeding AFFF concentrate and nine PFAS spiking chemicals, all having EPA developed toxicity data. The test included sampling and analysis of process waste feed streams, treatment chemical feed streams, solid and liquid process residue streams, and incinerator stack gases. No water is discharged from this facility and all solids generated are sent to a RCRA hazardous waste landfill for secure disposal.

EPA Test Methods OTM-45, OTM-50 and 0010 were all employed for sampling stack gas and analyses during the testing.

The results of the testing demonstrate that common legacy PFAS are effectively destroyed in the Aragonite incineration system at levels exceeding 99.9999 percent (%) destruction removal efficiency (DRE).

• 99.9999% DRE for seven spiked PFAS compounds during spiking runs
• 99.99 to 99.9999% for PFNA
• 99.99% for HFPO-DA. (Stack gas samples believed to have been contaminated from sampling glassware. This chemical is destroyed at 194°F and was below MDL in the two prior tests)

Stack gas emissions were modeled using EPA’s AERMOD program and were 2 to 8 orders of magnitude lower than any state ambient air quality limit or guideline in effect. The twelve compounds for which ambient impacts were modeled include PFBA, PFHxA, PFOA, PFNA, PFDA, PFDoA, PFBS, PFHxS, PFOS, FOSA, HPFO-DA and 6:2 FTS.

PFAS treatment and destruction technologies have been studied, demonstrated and commercialized over time. As the technologies are advanced, more PFAS removal and destruction mechanisms continue to be discovered and explored.  The verification of PFAS destruction and removal efficiency (DRE) adopted by the technology developers has ranged from monitoring of only a few regulatory PFAS, to comprehensive monitoring of nontarget PFAS for products of incomplete destruction (PID), and to total fluorine mass balance.  While a greater and deeper understanding of mechanisms, pathways and kinetics are needed to avoid discharges of PIDs and harmful terminal products, the growth of emerging technologies also increases the global needs of technical guidance and strategies on verifying the readiness and acceptance of different technologies.

USEPA PFAS technology evaluation framework (TEF) identified the key factors to verify PFAS treatment technologies, however, it has not introduced the methods, tools, approaches and strategies that can be used to guide on technology evaluation, selection, and ultimately management of PFAS treatment systems.  Through a demonstrated project to destroy PFAS in the spent PFAS-laden ion exchange resin, supercritical water oxidation (SCWO) was thoroughly examined using common and emerging methods to verify PFAS DRE, PID associated with non-target PFAS, corrosion concerns and generation of unwanted non-PFAS parameters in the solid, gas and liquid effluent discharges from the system.  Through this case study, it reveals the concern of state agencies on PFAS destruction technology, the essentiality of PFAS destruction verification strategy to mitigate known and unknown consequences from any aggressive reactions that destroy PFAS.  This is the first study that uses comprehensive monitoring program to verify PFAS destruction using SCWO.

Such strategy is applicable to other technologies and different industrial applications. The presentation will evaluate how such verification strategy can be applied and adjusted based on different goals and purposes in a semiconductor industry, such as:

• Decentralized vs centralized (end of pipe) treatment processes.
• Reclaim goals –higher reclaim rates lead to concentrated waste streams which may lead to ZLD or MLD.
• Segregation and collection of PFAS sources (especially around the Lithography tools) for reducing the PFAS load in the waste streams.
• Potential to generate or alter concentrations, types and composition of PFAS in Point of Use abatement units.
• PFAS in solids vs liquid streams, recyclable and reusable wastes.

Additionally, the PFAS destruction verification strategy should consider the stakeholder acceptance.  A summary of state programs on PFAS treatment technology evaluation criteria highlighting their concern of GHG, energy consumption and sustainability comparing between technologies for protection of human health and the environment beyond PFAS will be included in the presentation.

The widespread and pervasive nature of PFAS contamination necessitates the development and implementation of effective destruction technologies. However, because of the strength of the carbon-fluorine bond, PFAS are extremely difficult to break down. The application of destruction technologies may leave behind products of incomplete destruction or create reaction conditions that transform the structures into new, potentially more toxic or persistent chemicals. Characterization of the efficiency of PFAS destruction therefore requires careful documentation of all organofluorine going into and out of a treatment system.

In this talk, we will present a framework for the evaluation of PFAS treatment technologies within a regulatory context. We will discuss how to incorporate analytical techniques such as aggregate methods, target analysis, and emerging methods to track PFAS in various media, emphasizing the importance of a mass-balance approach to track the organofluorine mass throughout treatment systems.

PFAS releases from Aqueous Film-Forming Foam (AFFF) use at the Rutland – Southern Vermont Regional Airport (RSVRA) have been documented since the 1980s. The PFAS contamination at the RSVRA and in nearby drinking-water supplies provide a unique study area to examine PFAS transport and transformation in both the overburden and fracture rock aquifer. Stone Environmental in collaboration with Vermont Geological Survey performed site characterization at source areas and used analytical results in several media types to better understand the fate and transport of PFAS in the environment. Stone’s session will focus on source area investigation, fate and transport of PFAS in unconsolidated materials and stormwater infrastructure, and potential pathways to the bedrock aquifer.

The study area is unique because of many aspects, including multiple source areas and varying ages of the AFFF releases within the 37 sq. mi. RSVRA, and varying environmental factors influencing PFAS transport. The predevelopment overburden geology at the airport has been significantly reworked by human activity with blasting, cutting, and filling to create the runways and buildings. The thickness of unconsolidated materials overlying bedrock varies from 3 feet up to 62 feet below ground surface. Saturated conditions in the overburden are variable and many of the borings did not encounter groundwater or had shallow groundwater. The combination of shallow fractured bedrock overlain by PFAS contaminated soil and shallow groundwater creates vulnerable conditions for the transport of PFAS to the bedrock aquifer.

Groundwater and stormwater hydraulic divides exist at the Site. Direction of groundwater flow generally mimics the sitewide topography and flows radially from the topographic highs defined by the runways. Stormwater conveyance systems discharge runoff and shallow overburden groundwater at eleven outflows across the RSVRA. Receiving waters to the north and east of the airport include an unnamed tributary to Otter Creek and to the west and south include the riparian zone of the Mill River. The stormwater conveyance system is accelerating the transport of PFAS and ultimately creating secondary source areas that may be contributing to bedrock contamination.

Analytical results were interpreted using pie charts to look at the dominant PFAS compound in each source area, linking source areas to downgradient and offsite contamination based on PFAS ratios. Organic content, top assay, and leachability were also assessed to better understand the movement of PFAS in the environment. Based on the PFAS signatures in groundwater, it is likely that the two main AFFF products used at the RSVRA are the PFOS formulations, such as those manufactured by 3M, and non-PFOS formulations, such as Lodyne® and Ansul®, which are fluorotelomer based.

Materials to be presented include surface water characterization during different flow regimes and analysis of hydrographs and stormwater infrastructure, how source area data was evaluated to better understand the type of AFFF release, how PFAS is transforming from the source area to the impacted sensitive receptor, and the structure and variability of the unconsolidated materials. This session will discuss the in-depth conceptual site model and will segue into the bedrock aquifer physical and chemical characterization presented by VGS.

Please join us for a light breakfast and refreshments from 8-8:30 AM (provided).

Per- and polyfluoroalkyl substances (PFAS) become distributed in the environment after release from a source.  This distribution occurs through a series of transport and transformation mechanisms.  Atmospheric releases that lead to wet or dry deposition have not been well characterized and play an important role in understanding sources, migration patterns, and areas of impact.  The New Jersey Department of Environmental Protection (NJDEP) has conducted a two-year study entitled, “PFAS in Precipitation and Ambient Air” which included up to six precipitation collection sites and two high volume ambient air samplers set across the state to understand areas of release, transport, and deposition.  Site selection focused on sites included in the National Atmospheric Deposition Network (NADN).  Year 1 sites were set at active NADN National Trends Network (NTN) or Mercury Deposition Network (MDN) sites.  Sample collection and analytical methods all followed optimized procedures established by the Wisconsin State Laboratory of Hygiene, the sole analytical laboratory for the NADN. Weekly precipitation samples were collected at four sites in Year 1 and six sites in Year 2. Thirty 24-hour ambient air samples were collected at two sites for one annual cycle. Thirty-three per- and polyfluoroalkyl analytes were quantified in the Year 1 samples.  These 33 analytes included eleven perfluorocarboxylic acids (PFCAs, e.g. PFOA and PFNA), eight perfluorosulfonic acids (PFSAs, e.g. PFOS), three n-fluorotelomer sulfonic acids (FTSAs), seven perfluoroalkyl sulfidimides (FASAs) and four individual PFAS of concern (e.g. HFPO-DA, a GenX chemical).  An analytical method to quantify an additional PFAS, the novel, newly discovered ClPFPECA (a.k.a. monofunctional surfactant, or MFS) was added to the method for the Year 2 samples.  Year 1 data show a high percentage of detections for multiple PFAS at all sites, with PFCAs dominating the total PFAS detected at most sites.  However, unique fingerprints at specific sites included large periodic contributions from HFPO-DA (a GenX chemical) and PFOS that were evident and are expected to contribute to source identification.  Analysis of Year 1 data shows the importance of determining the flux (ng/m2/yr) of PFAS deposited to land/water as opposed to the concentration levels (ng/L).  The highest flux of PFAS was found at the site that had relatively lower concentrations of PFAS and was dependent on the amount of precipitation that fell at that site.  Preliminary results for Year 1 indicate an annual flux of 2,035 ng/m2/yr at the Washington Crossing site, 2,256 ng/m2/yr at the Edwin B. Forsythe National Wildlife Refuge, 3358 ng/m2/yr at the Cattus Island site, and up to 6,316 ng/m2/yr at the Rutgers New Brunswick sample collection site.  The Cattus Island site showed a larger contribution of perfluoroalkyl sulfonates (PFSAs) to the total PFAS flux, and the flux determined at the Rutgers New Brunswick site was dominated by GenX, with 3,482 ng/m2/yr of GenX contributing to the total flux at this site.  Data for the six Year 2 wet deposition sites and two ambient air sample collection sites is currently being evaluated and will be included in the presentation.

Per- and polyfluoroalkyl substances (PFAS) are found in the environment throughout the world. Background concentrations of PFAS in soils in New England and the central Atlantic region are currently a topic of interest, particularly in terms of how the background concentrations compare to concentrations at sites with discharges and how PFAS background is regulated. In this presentation, we will take a closer look at the PFAS occurrence data for shallow soil in New Hampshire compiled by the United States Geological Survey (USGS), including a look at confirmatory data collected at a subset of sites, and what the data tell us about “background” PFAS concentrations in shallow New Hampshire soil. We will also describe how New Hampshire’s Soil Remediation Standards (SRS), which went into effect in December 2024, were developed, noting that New Hampshire is one of the few states in the nation that currently regulates PFAS in soil at contaminated sites at levels protective of groundwater quality. In addition, we will look at how the background threshold values (BTVs) for perfluorooctanoic acid (PFOA), perfluorooactanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS) in shallow soil were developed by the New Hampshire Department of Environmental Services (NHDES) and how the BTVs, and the occurrence data in general, relate to NHDES’ SRS for PFAS.

The primary objective of the study was to quantify how representative a single point-in-time sample is when PFOA or PFOS concentrations fall between 3.5 and 10 ppt, or when the Hazard Index  exceeds 1 while PFOA and PFOS remain below 2 ppt, or when test results are close to the Maine Interim Drinking Water Standard for PFAS, currently  20 ng/L for the sum of six PFAS (PFHpA, PFHxS, PFOA, PFOS, PFNA, and PFDA) or SUM6. The study proposed sampling 11 locations for 10 months to assess variability by using consistent sampling personnel and methods. A secondary objective was to determine whether the new EPA Method 1633 would produce data comparable to results obtained using the methodology DEP currently utilizes for evaluating PFAS in drinking water, a Modified EPA Method 537 with Isotope Dilution (537MOD).  To further evaluate geochemical variation between the study sites, the samples were analyzed for general water chemistry during two rounds, using a standard DEP analyte list in August and December. This parameter list is commonly used by MEDEP to assess ground and surface water chemistry at landfill sites. These parameters were evaluated to assess water chemistry variations between locations and potential correlation to PFAS concentrations or variability.

Overall, the data quality seen throughout this study is comparable to PFAS data routinely collected by DEP. It is not uncommon to have occasional batches of data affected by laboratory QC issues, for which applicable biases are noted. Importantly, no SUM6 analytes had to be rejected for data quality issues, and the dataset as a whole is considered suitable for meaningful analyses.  Data were evaluated in several ways to assess the representativeness of a single residential well sample result relative to the Maine SUM6 or to the federal MCL values for PFOA and PFOS. SUM6 concentrations were evaluated to assess seasonal variability of the highest and lowest value for each sample point throughout the study period. At seven out of eleven locations the lowest SUM6 sample point values occurred in sampling events 9 and 10 (November and December); this may be more attributable to hydrogeological reasons than analytical chemistry reasons. By comparison, five locations had their highest SUM6 detection in Sample Events 1 and 3 (March and May.  Results showed that variability in samples collected over multiple events in succession was low, across SUM6 concentrations spanning multiple orders of magnitude. The relative percent difference (RPD) was used to assess field duplicate results, and to compare results from the repeated sample events to initial data and to the means for all data in the study. For all locations, calculated RPDs for PFOS ranged from 0.26 to 11.6, for PFOA from 2.41 to 20.67, and for the SUM6 from 1.71 to 30.39. RPD values are all within the typical validation standard of < 30% for aqueous duplicates.  Additional methods were employed to evaluate potential correlations between measured PFAS and water quality parameters such as pH, total organic carbon, dissolved oxygen, and sulfate.

The Environmental Protection Agency published detailed guidelines for the analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous, Solid, Biosolids, and Tissue Samples in December 2024. To internally harmonize and automate data processing and quality control (QC), we distilled the guidelines into their most relevant components and introduced practical simplifications and modifications. Many of the requirements remain difficult to interpret, and some QC criteria cannot be easily evaluated, even when using reports from accredited laboratories.

In this work, we compare various reports, highlight common misinterpretations, and present strategies to ensure that reported PFAS concentrations are accurate and reliable. We provide practical guidance on how to apply the EPA criteria using the information typically available in laboratory reports. The focus is on interpretations of the retention time criteria and ion abundance ratios, both critical for avoiding ghost peaks and matrix interference common in environmental and biological matrices. Because these parameters are often missing in reports, we demonstrate how they can be derived from available data.

This approach provides a practical framework for applying EPA guidelines in real-world contexts and supports consistency in PFAS QC across disciplines.

EPA 1633A has a standardized on a list of 40 PFAS. While this list represents a good base of PFAS and precursors of regulatory interest, it is a short subset of PFAS that are present in the environment, missing shorter chain sulfonamides, phosphate based PFAS, neutral PFAS such as fluorotelomer alcohols and more.  One of the major challenges with PFAS are their sheer diversity of structure, which makes the design of extended target list methods challenging as any approach needing a pre-concentration step such as solid phase extraction (SPE) for lowered reporting limits is also selective, Weak Anion Exchange (WAX) for example selecting for anionic PFAS. While non-target analysis can provide extended information, it is not quantitative. With the objective of increasing quantitative PFAS coverage and extending EPA 1633, we pre-selected nearly 100 PFAS as candidates, validated both direct-injection and SPE LC-MS/MS methods, assessed fit to 1633A, and analyzed samples from various sources including ambient sites, contaminated sites and waste streams.

We selected PFAS based on literature review and standards availability, including chain length extensions for PFAAs from C2 (TFA)-C18, fluorotelomer alcohols, phosphates such as 6:2 DiPAP, AFFF active ingredients, C4-C6 sulfonamides such as FBSA and PFHxSA, ethers such as Nafion BP2 and more.

Results showed that the PFAS fell into four types: 1) Thirty-five of the new PFAS studied including 6:2 DiPAP and short chain sulfonamides were reportable through an extended 1633A approach. 2) Fluorotelomer alcohols needed an independent workflow. 3) Ultrashorts, such as TFA, needed a separate instrumental run partially compatible with 1633A. 4) Several other PFAS such as cationic and zwitterionic AFFF ingredients were not compatible with 1633A preparation or analysis. Preliminary results show 6:2 DiPAP was present at high levels in municipal waste effluents/biosolids and TFA was high in municipal leachate. Our study provides a blueprint for the extension of 1633A-type target analysis methods.

Advancements in high-resolution mass spectrometry (HRMS) have significantly improved the detection and characterization of contaminants of emerging concern (CECs) through non-targeted analysis (NTA). NTA enables the investigation of analytes without prior knowledge of site-specific contaminants or the use of reference standards. These workflows can be tailored to project-specific needs, offering detailed characterization of site-relevant analytes. NTA is particularly effective for identifying complex contaminants such as per- and polyfluoroalkyl substances (PFAS) across diverse applications, including environmental forensics, water quality monitoring, food safety, toxicology, and human exposure assessment.

In this study, we present laboratory results from the 2024 PFAS-NTAIL study conducted by NIST, showcasing NTA methodology using a representative dataset. Data were acquired using HRMS for precise mass accuracy and ion mobility-mass spectrometry (IM-MS) for enhanced separation of branched isomers. Multiple analytical workflows were employed to identify precursor PFAS compounds from the NIST PFAS Suspect List. Each identified compound was assigned a Confidence Level based on the strength of supporting experimental evidence.

This approach is adaptable to a wide range of field investigations and complements standard analytical methods. For sites requiring detailed characterization of individual PFAS or other CECs, NTA offers a powerful tool for comprehensive contaminant profiling.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with increasing evidence of bioaccumulation in the human food chain. Animal-derived proteins such as eggs, pork, poultry, and beef, as well as certain fruits and vegetables, represent potential exposure pathways. Contamination may occur through feed, water, soil, or other environmental inputs. In recognition of these risks, the European Union has established maximum levels for four PFAS compounds (PFOA, PFOS, PFNA, PFHxS) in eggs and meats, while U.S. regulatory and public health interest continues to expand.

To address these emerging concerns, two complimentary approaches were developed. For eggs, an automated solvent extraction and dual-phase SPE cleanup was developed, reducing analyst involvement, improving reproducibility, and increasing throughput. The automated extraction requires less than 15 minutes per sample, and the dual-phase SPE GCB/WAX (Graphitized Carbon Black + Weak Anion Exchange) processes up to eight samples in under 70 minutes, ensuring robust cleanup for complex matrices. Data will be presented comparing PFAS concentrations in cage-free store-bought eggs and backyard chicken eggs. When evaluating meats and plant-based matrices, a scaled-down QuEChERS-based approach where sample volumes and salts were reduced to minimize solvent use, lower costs, and generate less hazardous waste. Dual-phase SPE GCB/WAX cartridges were then applied for cleanup, and increased LC-MS/MS sensitivity ensures reliable detection at this smaller scale. The reduced sample and salt amounts improve efficiency and throughput, as there is less material to homogenize and smaller salt packs dissolve more easily with less clumping for easier handling.

Together, these approaches aim to provide a more comprehensive understanding of PFAS occurrence across the food supply chain and demonstrate how automation and adaptable sample preparation can support regulatory compliance and public health decision making. Importantly, these approaches are designed to be transferable, enabling other researchers to adapt them to their own workflows for broader PFAS monitoring efforts.

Plant uptake from contaminated soils is a major pathway by which per-and polyfluoroalkyl substances (PFAS) enter our food system. Accurately characterizing that uptake is key to assessing the risk of PFAS contamination and to developing effective mitigation strategies. A survey of 15 contaminated farm fields in perennial grass-based hay and pasture in Maine showed high variability in soil-to-plant PFAS transfer factors (TFs), with perfluorooctanesulfonic acid (PFOS) TFs varying tenfold. That study highlighted the need to identify soil and plant characteristics that could explain this variability. The current study builds on that research by both increasing the number of sites sampled and expanding the suite of potential explanatory variables measured. Eleven additional fields were sampled in 2023 for soil and plant PFAS concentrations using a co-located sampling approach as in the original study. A suite of soil properties measured included soil texture, pH, organic matter, cations, cation exchange capacity, and bulk density, whereas plant-level measurements included species composition, cut number, biomass, growth stage, and forage quality parameters. Principle components analysis followed by multivariate regression analysis were used to identify plant and soil parameters that significantly influence PFOS TFs. In preliminary analyses, soil characteristics, such as iron and aluminum (oxides) and organic matter, that affect the concentrations of soil exchange sites for potentially binding PFOS were inversely associated with TFs. The most abundant PFOS precursors detected in soils were NEtFOSAA and PFOSA, and both showed positive associations with PFOS TFs. Among the plant characteristics, cut number had the strongest effect with PFOS concentrations being higher at second cut than first cut. Uptake of PFOS precursors into aboveground tissues was consistently low. Collectively, these preliminary results provide some of the first landscape-level documentation that both soil chemical properties and plant management factors may jointly shape PFOS uptake, offering critical insights for risk assessment and mitigation in forage systems. Detailed results will be presented at the forum.

Soil contamination with perfluoroalkyl and polyfluoroalkyl substances (PFAS) from historical sludge applications is an emerging agricultural crisis. In Maine and elsewhere, forage producers (dairy, beef, and hay) are one of the most impacted groups. The goal of this project was to identify strategies to reduce risks associated with growing forages on PFAS-contaminated land. A replicated field trial was initiated in late 2023 on a PFAS-impacted farm to investigate the effects of various forage management practices on perfluorooctane sulfonate (PFOS) uptake by selected perennial and annual forage plants. Experimental treatments included crop species, harvest timing, harvested product, cutting height, and seasonality. PFOS uptake was determined in 2024 and 2025 by analyzing co-located plant and soil samples and calculating PFOS transfer factors (TF; plant concentration divided by the soil concentration, both on a dry matter basis). Forage quality characteristics, leaf:stem:seed head mass ratios, and estimated evapotranspiration were also evaluated as possible explanatory variables. First year results indicate that seasonality (i.e., growing period) has a strong effect on PFOS levels of perennial species, where PFOS TFs of aftermath growth harvested in August were 35-109% higher than TFs of the original spring growth harvested in May and June for each perennial species. Seasonality may also play a role with annuals as PFOS TFs of the two summer annuals (pearly millet and corn) were higher than the two spring annuals (oat and pea). Harvested product also had a substantial effect. In all cases tested (winter triticale, spring oat, field pea, and corn), PFOS TFs in grain was zero or close to zero as compared with TFs from 0.025 to 0.225 for the whole plant forages of these species. For corn, harvesting snaplage (cob, grain, and husk) is another promising strategy to reduce PFOS concentrations, with a TF of 0.01 compared with 0.06 for whole plant corn silage. Results from the second year of the trial will be incorporated and presented, and together they offer farmers and decision-makers actionable information to guide recommendations and management options for PFAS-impacted farms.

Agricultural communities impacted by land spreading of biosolids can be exposed to PFAS through multiple exposure pathways. In Maine, statewide investigations have identified high soil concentrations of PFAS in farm fields with a history of biosolids application and contamination of nearby private wells, with some wells reporting PFAS levels in the hundreds to thousands of parts per trillion. Elevated PFAS levels have also been measured in freshwater fish, turkey, and deer near impacted fields, prompting consumption advisories for people eating sport-caught fish and game. Blood testing can provide information about potential exposures from these various pathways and can help to inform health monitoring and interventions. Previously reported blood serum levels from a limited number of Maine residents with highly contaminated private wells reported PFOA and PFOS serum concentrations above 600 ng/mL and 2,000 ng/mL, respectively. In response to widespread PFAS contamination, the State of Maine provides funding to support blood testing for individuals working on or living near contaminated farmland and established public health oversight by making PFAS blood testing results a notifiable condition in June 2025. For serum levels sufficiently above background, case follow-up will be undertaken to investigate possible exposure sources and inform strategies for exposure reduction. We will describe the framework used for electronic PFAS blood test reporting in Maine, an update on tests reported to date, and how toxicokinetic modeling based on PFAS concentrations measured in water, agricultural products, and fish and game can be used to identify possible exposures that could result in elevated serum levels. Serum levels can be compared to existing human biomonitoring (HBM) guidance values to support decision making, including guidance values used by the National Academies of Science, Engineering, and Medicine (NASEM). In the first four months since the rule went into effect, 35 PFAS test results have been reported, 10 of which exceed NASEM’s recommended guidance for additional clinical follow up. We will discuss the different components of public health oversight of PFAS blood testing, including approaches for determining when to do case follow-up, and efforts to support clinicians treating patients with elevated PFAS exposures.

The SCDES Office of Science Services (OSS) has collected more than 1200 PFAS private well drinking water samples as part of its ongoing state-wide assessment project. SCDES has developed an effective risk communication tailored to the residents’ existing awareness of the issue and the magnitude of the PFOA and PFOS impacts identified in their well water. Communicating results to residents, many of whom are not familiar with PFAS, the “forever chemicals” detected in their well water, presents substantial challenges to OSS staff, particularly in cases where the impacts may originate from the resident's own wastewater. The issue is further complicated by the substantial PFAS exposures project participants receive from their diets, consumer goods, and other environmental pathways.

PFAS were identified in roughly half of the well water samples collected. Eighteen percent of the samples contained PFOA or PFOS concentrations greater than the 2023 Maximum Contaminant Levels, which are used as the project’s screening levels. SCDES has discovered several previously unknown areas of PFAS contamination in groundwater during the project, which can be differentiated by the profiles of PFAS detected. PFAS released in wastewater, either from on-site septic systems or public sanitary infrastructure, appears to be the most widespread contributor to PFOA and PFOS contamination in well water in South Carolina, though several other potential releases have been identified.

The project is funded by a $10 million budgetary Proviso allocated by the State Legislature to assess and mitigate emerging contaminants in private well water and small public drinking water supplies. The funding covers outreach and sampling efforts carried out by SCDES and the implementation of risk management measures, consisting of the provision of point-of-use water filtration (POU) or the extension of public water service.

SCDES communicates directly with residents when elevated PFOA or PFOS are detected in a sample, providing a letter describing the results and information about how individuals can reduce their risk of exposures to PFAS, along with a POU water filter. Fundamental structures and properties of fluorocarbons are described with reference to petroleum hydrocarbons, which residents are familiar with from their life experiences. PFAS results, expressed as parts per trillion in water, are described using analogies to concepts that are understandable to the participant, such as teaspoons of water in a local reservoir.

Potential health effects associated with PFAS exposure are discussed with the residents, emphasizing kidney and liver disease, cholesterol dysregulation, and childhood immunosuppression for childbearing-aged residents. All potential adverse health effects are discussed with a focus on chronic exposures, with the historical decreases in PFOA and PFOS observed by the NHANES blood serum analysis presented for context.

Without exception, residents who participate in the project express gratitude for the attention and comprehensibility that the SCDES risk communication strategy brings to the issue. The strategy is also successfully employed in other forums where PFAS impacts to the environment are discussed, such as public meetings related to contaminated sites and academic presentations.

In 2023, the United States Geological Survey found PFAS in 45 percent of tap water samples collected across the country. Meanwhile, the National Gardening Association estimates more than 43 percent of US households are growing some form of food in a home garden. Given these statistics, potential uptake of PFAS from irrigation water into homegrown produce is a public health concern. This is especially true for residents with home gardens and private wells near hazardous waste sites impacted by PFAS contamination.

Potable use regulations exist to protect human health from PFAS in drinking water, but irrigation-based regulations incorporating PFAS uptake from water into produce have not been established. Although sampling has been conducted at multiple sites and research is ongoing, knowledge gaps exist regarding the mechanisms associated with PFAS uptake and accumulation in plants from irrigation water. Uptake studies have primarily been conducted in controlled settings, such as soil pot or hydroponic studies. These studies often include high PFAS concentrations and limited plant species, and either omit soil or focus on uptake from soil, and therefore, are unlikely to yield results that are representative of real-world field conditions. This complicates the interpretation of results, and therefore, the ability to develop appropriate regulations.

This presentation provides empirical data and results from sites showing limited transfer from irrigation water to plants, summarizes supporting peer-reviewed literature, and discusses the current regulatory status. Results are placed into context showing a low potential for human health risk for this migration pathway. This presentation concludes with a summary of the data gaps and recommendations for further research that are needed to definitively answer the reoccurring question: is this water safe for irrigating my vegetable garden?

PFAS are known contaminants in many industrial and commercial waste streams and are also increasingly being detected in domestic wastewater. Residential wastewater is commonly discharged through decentralized onsite septic systems that can be point sources for PFAS contamination of groundwater, necessitating an understanding of the types and levels of PFAS in septic system wastewater effluent. Monthly effluent sampling of four community septic systems indicates total PFAS concentrations (∑40) ranging from 6 - 97 ng/L, primarily attributed to PFOA, PFPeA, and PFHxA.  Two of the sites rely on simple settling tanks prior to effluent discharge, while the other two sites possess a secondary treatment unit (biological trickling filter) installed for effluent nitrate removal. PFAS composition is variable over time at the two sites with simple settling tanks, implying that residential wastewater discharges may be episodic depending on consumer behavior and product use. In contrast, PFAS profiles are fairly consistent at the two sites which have secondary treatment units, suggesting that, similar to treatment trains at publicly owned treatment works facilities (POTWs), septic system treatment installations may interact with PFAS through biochemical transformations or sorption mechanisms. In conjunction with statewide sampling efforts indicating low-level PFAS in nearly all raw water sources for public water systems, this work underscores the need for PFAS source reduction to protect groundwater from further PFAS contamination.

In 2020, the Town of Nantucket (the Town) initiated a voluntary, multi-phase assessment program to better understand the presence of per- and poly-fluoroalkyl substances (PFAS) in the environment. This effort has focused on assessing PFAS presence at Town facilities and developing an understanding of the transport mechanisms and migration pathways by which PFAS compounds reach potential receptors, whether by human transport or environmental migration. A primary step in the process of understanding the island-wide PFAS cycle has been to obtain an improved understanding of potential PFAS sources contributing to the Surfside Wastewater Treatment Facility (WWTF) as well as relative to the Surfside WWTF’s management and disposal of biosolids. This understanding is now driving efforts to break-the-cycle by assessing opportunities for source reduction and control. To-date, three years of sample collection and analysis have been completed to evaluate PFAS concentrations and loads throughout the Town’s wastewater system.

Guided by a Wastewater Decision Matrix developed as a road map to identify and assess PFAS sources received at the Town’s Surfside WWTF, the sampling effort transformed over time to accommodate findings and adapt to new understandings of PFAS sources and potential mitigation points. Loading analyses were crucial in the evolution of sampling and analysis. In high load-contributing non-point sources such as the collection system, sampling has expanded into subareas to aid source identification.

The Town will also be considering future pilot studies focused on PFAS removal from two high PFAS load points identified during the sampling assessment – landfill leachate and dewatering centrate. Landfill leachate was determined to contribute approximately 59% of the PFAS load that enters the Surfside WWTF per results from years 1 and 2. Bench studies conducted during year 2 suggested the leachate could be a good candidate for PFAS removal via foam fractionation. Dewatering centrate was added as a sampling point during year 3 after initial investigations determined that the centrate was recycling a significant load of PFAS from sludge dewatering back to the treatment train. Additional studies are needed to determine the best course of treatment for centrate, but initial tests suggest it may respond well to foam fractionation as well.

This presentation will walk listeners through the execution and results of three years of PFAS sampling efforts on Nantucket, results from the initial bench studies investigating both landfill leachate and centrate, as well as the actionable next steps the Town will be considering as they take a proactive approach to tackling PFAS in wastewater.

Per- and polyfluoroalkyl substances (PFAS) remain one of the most difficult contaminants to address for waste and wastewater managers. Historically used in industries such as plating, finishing, semiconductors, and chemical manufacturing, PFAS continues to accumulate in surface water, sludge, landfills, and treatment systems, posing long-term liability. Traditional treatment and disposal methods such as granular activated carbon, ion exchange, and offsite incineration or disposal often fall short by transferring the problem to secondary waste streams, leaving facilities exposed to cost and liability. This presentation describes the transition from laboratory validation through pilot-scale testing to the first full-scale integrated foam-fractionation (FF) and electrochemical oxidation (EOx) treatment train designed to permanently destroy PFAS in metal finishing wastewater.

Encouraged by promising laboratory and pilot data, the customer advanced to full-scale implementation at three facilities in total. Standardized, containerized electraCLEAR™ systems were deployed, each capable of treating up to 100 gallons per day of concentrated foamate with influent PFAS levels as high as 83 mg/L and total organic carbon up to 950 mg/L. Prior to electrochemical oxidation, a full-scale foam-fractionation unit concentrates raw wastewater—up to 70,000 gallons per day—by three orders of magnitude. Each modular treatment system included dual electrochemical reactors, integrated gas and vapor controls, batch tanks, and safety systems, all within a climate-controlled 20-foot container for rapid deployment and ease of integration.

Performance data confirmed the robustness of the integrated approach. Laboratory testing demonstrated PFAS destruction exceeding 99.9%, with some compounds achieving greater than 99.99% removal within 48 hours. The degradation pathway showed transient short-chain intermediates that were subsequently mineralized, a conclusion supported by Total Oxidizable Precursor assays. Pilot-scale testing validated these results under field conditions, demonstrating 98.8% fluoride recovery—evidence of near-complete mineralization to non-toxic end products.

Full-scale operation began in April 2025. Within the first three months, a single system processed 8,365 gallons of concentrated foamate, destroying approximately 2.5 kilograms (5.4 pounds) of PFAS. Across the entire treatment train, more than 8.3 million gallons of raw wastewater were managed onsite during this period, reducing reliance on offsite disposal. The success of this initial system has prompted expansion to two additional facilities scheduled for 2026 and 2027.

The project also underscored the importance of incremental scale-up. Laboratory results guided electrode material selection and process parameters, while pilot testing revealed operational nuances such as vapor-phase PFAS risks, which were mitigated through closed-loop condensers and activated carbon polishing. These lessons directly informed full-scale design, resulting in a resilient, energy-efficient, and automated treatment platform capable of consistent performance under variable influent conditions.

This case study demonstrates that integrating foam-fractionation with electrochemical oxidation provides a technically validated and field-proven pathway for onsite PFAS destruction. By coupling concentration and mineralization, the system offers a scalable, cost-effective, and sustainable solution that moves beyond capture-and-dispose strategies toward true elimination of PFAS at industrial facilities.

This presentation summarizes key considerations and lessons learned from PFAS sampling and analysis at two sites where over 4,000 groundwater samples have been collected since 2017. During this period, PFAS analytical methods evolved from laboratory-specific modified Method 537 (537Mod), to methods compliant with Department of Defense Quality Systems Manual (DoD QSM) Table B-15, and ultimately to the draft and final versions of EPA Method 1633. Many wells were sampled repeatedly over the years, allowing comparison between results generated by 537Mod/QSM Table B-15 methods and those obtained using Method 1633. This presentation will evaluate the comparability of historical PFAS data to results produced by Method 1633.

One of the major challenges in PFAS groundwater sampling and analysis is the proper handling of aqueous samples with elevated levels of suspended solids, both in the field and laboratory. Our sampling programs included the collection of vertical aquifer profile (VAP) samples, which are discrete groundwater samples taken at multiple depths from temporary boreholes to assess PFAS transport through the aquifer. Due to their grab-sample nature, VAP samples often contain high suspended solids. Additionally, samples from permanent monitoring wells can also exhibit elevated solids, despite proper well development and low-flow sampling protocols. High solids content can clog solid-phase extraction (SPE) cartridges during laboratory extraction, often requiring additional preparation steps such as extra cartridges, sample dilution, or centrifugation. Moreover, depending on the project’s data quality objectives (DQOs), PFAS concentrations in solids-laden samples may not accurately represent aquifer conditions, as particle-bound PFAS may not migrate with the dissolved phase in groundwater.

This presentation will share our experiences and lessons learned from managing suspended solids in groundwater samples over multiple years of PFAS investigations. Topics will include:

1. Evaluation of drilling technologies used for VAP sample collection and their influence on suspended solids generation;
2. Use of field turbidity measurements to inform laboratory preparation procedures;
3. Impact of laboratory preparation procedures on PFAS concentrations in VAP samples, including centrifugation vs. no centrifugation, timing of extraction internal standards (EIS) spike (pre- vs. post-centrifugation), and sample volume (500 mL vs. 125 mL);
4. Comparisons between VAP and corresponding permanent monitoring well results to assess sample representativeness and potential bias associated with elevated solids.

Our experience highlights the importance of earlier project planning and proactive communication among project team, data users, and laboratories to ensure alignment of sampling, preparation, and analytical protocols in support of generating accurate, defensible PFAS data.

In Summer 2025, the Town of Nantucket (the Town) conducted surface water and foam surveillance for PFAS at its public bathing beaches. The surface water sampling campaign was conducted in accordance with the Massachusetts Department of Public Health’s (DPH) May 2024 Operational Guidance for Bathing Beaches at PFAS-Impacted Waterbodies. This guidance establishes surface water action levels for eight individual PFAS, with an initial screening value of 20 nanograms per liter (ng/L). Across two sampling events, the Town collected a total of 40 surface water samples from 16 coastal beaches and harbors, three inland ponds, and two nearshore “background” locations. During both sampling events, foam was identified at two beaches. Surface water and foam samples were analyzed for 40 PFAS using EPA Method 1633A.

In July 2025, PFAS were detected in surface water at 12 of 21 locations. PFAS were not detected at the two background locations. The most commonly detected compound was PFOA (48%), which had a maximum detected concentration of 3.9 ng/L. Of the eight PFAS applicable to DPH’s established action level, PFBA was detected at the highest concentration (10 ng/L). No PFAS measurements exceeded the action level. One compound without an established action level (PFPeA) was detected at a concentration of 210 ng/L. When that location was resampled, PFPeA was not detected.

PFAS levels in foam were higher than surface water. One location had an individual compound (PFOS) detected as high as 30,000 ng/L. However, that sample did not meet the laboratory’s quality control (QC) requirements; the extracted internal standards were outside of acceptance criteria, and there was insufficient sample volume for re-extraction. At the other foam sampling location, an individual compound (again PFOS) was detected as high as 8,300 ng/L, in this case with no qualifier indicating that the extracted internal standard was outside of acceptance criteria. Because of the high concentrations detected in foam, the Town issued a foam advisory urging beachgoers to avoid contact with foam and to wash off after coming into contact with foam.

In both foam locations, all individual PFAS compounds in paired surface water samples were less than 20 ng/L.

Data from the August 2025 sampling event are pending.

This presentation will provide an overview of sampling methodologies for surface water and foam, analytical challenges associated with these environmental media, and an analysis of the spatial and temporal variation of PFAS concentrations seen on Nantucket. This presentation will also provide guidance for results interpretation and communication.

Questions have recently been raised about the suitability of using porewater samples collected with suction lysimeters to estimate PFAS mass discharge in the vadose zone. Multiple lines of evidence were evaluated to determine if porewater samples collected during a data gaps investigation (DGI) in the former fire training area (FFTA) at Ellsworth Air Force Base were reproducible and representative. Lines of evidence used include supplemental geologic and hydrogeologic data which show the presence of a semi-continuous silt/clay layer directly above the water table throughout much of the FFTA, and gravimetric moisture content results that demonstrate vertical groundwater flow at a depth of 15 ft is substantially limited due to semi-arid climatic conditions. Radial diagrams were used to visually demonstrate that there was negligible variability in porewater concentrations caused by varying sample yields in the deep zone. Additional lysimeters installed in the FFTA during the remedial investigation (RI) resulted in a small decline in the estimated PFAS mass discharge at the FFTA, which demonstrates that the number of lysimeter sampling points in this area is sufficient. Strong attenuation in total PFAS soil concentrations with depth validates the order(s) of magnitude reduction between shallow and deep porewater sample results. Recommendations for field data collection and guidance for estimating PFAS mass discharge in the vadose zone are presented.

In New England, seafood consumption is a major pathway for PFAS exposure, and American lobsters (Homarus americanus) have been found to contain some of the highest concentrations among commonly consumed seafood. As an iconic species central to the economy and culture of Maine and New Hampshire, PFAS levels in lobster tissue have implications for both consumer health and the resilience of fishing communities.

This study evaluates spatial patterns of PFAS contamination in Maine lobsters in relation to coastal land use. Lobsters were collected by the Maine Department of Environmental Protection in 2021 from 18 areas spanning seven lobster management zones. Shorter chained 5:3 FTC and 7:3 FTC along with long-chain perfluorocarboxylic acids (PFCAs), including PFTeDA, PFTrDA, and PFUnDA, were consistently the most abundant compounds across sites, while PFOS was consistently found in lower concentrations.

To explore potential drivers of contamination, land cover metrics from the National Land Cover Database including impervious surfaces, forested areas, and farmland, are being used in regression analyses to examine relationships between PFAS concentrations and nearby coastal land use. Early trends suggest that lobsters from more developed coastal waters may exhibit higher PFAS concentrations, supporting the hypothesis that land-based activities are a key source of marine contamination.

This study enhances understanding of how coastal land use shapes PFAS patterns in lobsters and provides critical information for identifying high-risk areas for further monitoring. By linking land use to contaminant exposure in lobsters, an economically and culturally important species, this work informs seafood safety considerations, fisheries management, and coastal community resilience in the face of emerging chemical threats.

On August 19, 20On August 19, 2024, there was a failure of the fire suppression system inside an airplane hangar at the Brunswick Executive Airport.  Approximately 1,450 gallons of aqueous film-forming foam (AFFF) concentrate mixed with 50,000 gallons of water were released.  Only a small portion of the AFFF was captured in cleanup efforts.   Some of the foam made its way into a Merriconeag Stream and Mare Brook, which flows into the ocean water in Harpswell Cove.  Some of the foam entered the sewer system and went to the Brunswick wastewater treatment plant, which discharges to the Androscoggin River.  Following the release, the Department of Environmental Protection (DEP) collected weekly water samples at several locations along the Androscoggin River, Merriconeag Stream, Mare Brook, and Harpswell Cove. The AFFF contained large quantities of perfluorooctane sulfonic acid (PFOS), which bioaccumulates in fish.  To determine the extent of PFOS bioaccumulation, DEP collected freshwater fish and marine fish and shellfish.  Preliminary results show minimal PFOS contamination resulting from the AFFF release in the Androscoggin River and severe PFOS contamination in Merriconeag Stream and Mare Brook.  Concentrations of PFOS in Harpswell Cove were high, prompting a temporary closure of clam flats to harvesting, and decreased in the months following the spill.24, there was a failure of the fire suppression system inside an airplane hangar at the Brunswick Executive Airport.  Approximately 1,450 gallons of aqueous film-forming foam (AFFF) concentrate mixed with 50,000 gallons of water were released.  Only a small portion of the AFFF was captured in cleanup efforts.   Some of the foam made its way into a Merriconeag Stream and Mare Brook, which flows into the ocean water in Harpswell Cove.  Some of the foam entered the sewer system and went to the Brunswick wastewater treatment plant, which discharges to the Androscoggin River.  Following the release, the Department of Environmental Protection (DEP) collected weekly water samples at several locations along the Androscoggin River, Merriconeag Stream, Mare Brook, and Harpswell Cove. The AFFF contained large quantities of perfluorooctane sulfonic acid (PFOS), which bioaccumulates in fish.  To determine the extent of PFOS bioaccumulation, DEP collected freshwater fish and marine fish and shellfish.  Preliminary results show minimal PFOS contamination resulting from the AFFF release in the Androscoggin River and severe PFOS contamination in Merriconeag Stream and Mare Brook.  Concentrations of PFOS in Harpswell Cove were high, prompting a temporary closure of clam flats to harvesting, and decreased in the months following the spill.

Due to the widespread nature of per- and polyfluoroalkyl substances (PFAS), large nationwide datasets containing measured PFAS concentrations in many media and matrices have been collected. To explore the extent of PFAS contamination in the USA and threats to aquatic resources, we retrieved surface water PFAS data warehoused in the USEPA’s Water Quality Portal (WQP) and fish tissue data from the National Aquatic Resource Surveys (NARS). For WQP surface water data, the EPATADA compiler and data quality system identified issues related to duplicate entries and lack of QC information; allowing for data cleaning prior to analysis. For samples above detection limits, perfluorooctanoic acid (PFOA) concentrations ranged from 0.17 to 248,000 ng/L and perfluorooctane sulfonate (PFOS) concentrations ranged from 0.20 to 1,860,000 ng/L. Less than 1% of all data were at or above chronic aquatic life criteria. NARS fish tissue data were converted from tissue concentrations to estimated water concentrations using the mean bioaccumulation factors (+/- upper and lower bounds) reported in Burkhard, 2021 for teleost fish. Fish represent a living passive sampler of sorts, accumulating PFAS over time prior to their collection and analysis. Estimated surface water concentrations were generally lower than the values report in the WQP, with PFOA ranging from 0.17 to 76 ng/L, and PFOS ranging from <0.01 to 1,000 ng/L when using the mean BAF to calculate water concentration. When evaluating estimated in-water concentrations using BAF, there were no samples estimated to exceed acute or chronic criteria, even when using the upper and lower boundary BAF values. Overall, this study demonstrates a range of methodologies for handling and cleaning national datasets to extract valuable information on the state of PFAS contamination in surface waters in respect to threats to aquatic life.

The extensive use of per- and polyfluoroalkyl substances (PFAS) in aqueous film-forming foam (AFFF) has led to widespread environmental contamination. In response, many responsible parties have undertaken large-scale investigations to characterize PFAS contamination across multiple environmental media. Since the mid-late 2000’s, remedial investigations conducted at the 29 sites included in this study have generated vast amounts of analytical data, often encompassing hundreds or thousands of samples at a single site across multiple environmental media (soil, sediment, surface water, groundwater, porewater), each with dozens of PFAS detections. This results in a complex, high-dimensional dataset that can be difficult to interpret using conventional univariate or bivariate analysis alone.

PFAS fate and transport in the environment is highly dependent on their perfluorinated chain length and functional group as well as a variety of site-specific factors including lithology, meteorology, hydrogeology, source composition, nature and extent of contaminant release, and physicochemical interactions with other contaminants. The relative contributions and interaction among these various factors on the overall magnitude of PFAS retention in the vadose zone and PFAS leaching to underlying groundwater remains somewhat uncertain and can only be fully interrogated by large empirical datasets from a diverse portfolio of contaminated sites. Therefore, there is a critical need to identify key compositional patterns, source signatures, and spatial trends across media and sites to improve the effectiveness and efficiency of current and future investigation and remediation efforts across different media and at PFAS-impacted sites.

This presentation will demonstrate the utility of multivariate statistical tools for simplifying and interpreting large PFAS datasets.  Specifically, this study applies conventional and multivariate statistical tools [specifically, Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA)] to a large PFAS dataset collected from 29 different sites across the continental United States to identify compositional patterns, source signatures, and spatial trends across groundwater, porewater, surface water, soil, and sediment. PCA revealed distinct clustering among PFAS differentiated by chain length and environmental media, with short-chain PFAS being far more common in aqueous media and long-chain PFAS being much more prevalent in soil and sediment. Notably, PFHxS was the most abundant PFAS in groundwater and porewater whereas PFOS dominated in surface water and solid media. Estimated PFAS vadose zone dilution attenuation factors (DAFs), which are the porewater-to-groundwater concentration ratios, were strongly correlated with chain length, reflecting differences in sorption behavior and mobility. PFAS concentration and composition profiles in soil indicated that the maximum total PFAS concentration in soil typically occurs in the upper 3 ft in arid climates but occurs deeper (3-5 ft) in sub-humid regions, highlighting the influence of hydraulic flux on vertical transport. PCA and HCA also revealed site-specific PFAS fingerprints and associations with geospatial and hydroclimatic variables such as temperature, precipitation, and depth to groundwater. PCA results also suggest that PFAS contamination at many sites is more spatially diffuse than traditional point-source plumes, likely due to the nature of AFFF application and historical usage.

Biosolids are impacted by Per- and Polyfluoroalkyl Substances (PFAS) through the concentration and accumulation of these compounds during wastewater treatment processes. PFAS enters the wastewater system from domestic sewage, landfill leachate, industrial processes (such as manufacturing of non-stick coatings, waterproof materials, firefighting foams, and metal plating facilities), and consumer products (clothing, food packaging, cosmetics), and subsequently becomes concentrated in biosolids as these persistent compounds partition into sludge during treatment. PFAS poses challenges to traditional biosolids management practices, as these compounds resist degradation during biosolids processing and can persist in the final biosolids product.

Characterization of the PFAS load in biosolids is critically important to determine the concentrations of PFAS that accumulate during wastewater treatment and to assess potential environmental impacts from land application and disposal practices.

In this study, select biosolids samples were analyzed for an extensive list of targeted analytes under an expanded EPA 1633A. This expanded method includes additional groups of analytes not included in published method, including Perfluoroalkyl Phosphinates (PFPIA), Polyfluoroalkyl Phosphate di-esters (diPAP), Fluorotelomer unsaturated carboxylic acids (FTUCA), perfluorinated sulfonylimides (PFSI), and “diprotics” which are notable for having two functional groups.

Results and discussion – results are compiled and discussed regarding composition of analytes in biosolids. Analytical considerations for the extraction and analysis of biosolids, including variable solid content and sample heterogeneity, will be discussed. Trends in PFAS accumulation and speciation in biosolids will be discussed as well as the implications for biosolids management and beneficial use applications across the types of PFAS present in the samples.

State regulatory agencies that have promulgated migration or impact to groundwater standards for soil often incorporate background concentrations, method detection limits, risk levels, and a model to estimate potential soil leaching. Soil leaching models for organic compounds typically rely on soil density, porosity, and a distribution coefficient based on organic carbon content. Many PFAS, however, are surface-active compounds that also sorb to the air-water interface (AWI) in unsaturated soil. This additional AWI sorption further reduces the potential for PFAS to leach from soil into groundwater. Other factors affecting these standards are that some agencies have adopted background soil concentrations that do not reflect site-specific or regional conditions, and some models may not consider appropriate dilution-attenuation factors. As a result, default migration to groundwater soil standards for PFAS are frequently overly conservative and overestimate the potential for PFAS to leach from soil into groundwater at concentrations exceeding drinking water or other applicable standards. The Massachusetts Contingency Plan (MCP) standards are used as an example. Default MCP Method 1 S-1/GW-1 standards (which are the most stringent soil standards and apply to drinking water source areas) for the six PFAS compounds regulated in Massachusetts range from 0.2 to 0.72 µg/kg and are based on background concentrations estimated for the adjacent state of Vermont. We applied the MCP framework to develop site-specific Method 2 standards that better reflect current scientific understanding of PFAS fate and transport and regional background concentrations. This approach incorporated current risk-based concentrations, Massachusetts surface soil background data, and a sorption model that includes AWI sorption. The resulting soil leaching Method 2 soil standards are between four times and more than an order of magnitude higher than the default Method 1 S-1/GW-1 standards. These results demonstrate that incorporating updated scientific understanding of PFAS behavior, particularly AWI sorption and realistic background concentrations, can lead to more accurate, scientifically defensible soil leaching standards and reduce unnecessary investigation and remediation while still protecting groundwater quality.

PFAS testing for soil and water has long been established in the environmental community. However, understanding PFAS destruction, removal, or capture from air emissions is a relatively new area of focus. The regulatory landscape is increasingly demanding more emissions data from various sources to assess their treatment capabilities and environmental health impacts.

In 2021, the EPA introduced Other Test Method 45 (OTM-45) for semi-volatile PFAS compounds, which was revised in 2024. Additionally, in 2024, the EPA issued OTM-50 for collecting volatile PFAS compounds in stack gas. The EPA continues to develop methodologies for capturing other PFAS compounds that may not be covered by these two methods and ambient systems are being evaluated as part of some source testing programs to determine the influence of outside contributors. These test procedures require a deeper understanding of how to structure a test program and recognize potential sources of sample contamination that could bias the results.

This presentation will focus on covering the basic principles, procedures, and recent updates in test guidance to determine PFAS emission rates from stationary sources.

On August 19, 2024, 1,450 gallons of aqueous film-forming foam (AFFF) mixed with 50,000 gallons of water was released from a hangar at the former Brunswick Naval Air Station (BNAS) in Maine. AFFF entered storm water drains and contaminated surface waters and resulted in the airborne dispersal of foam by wind. In response to community concerns about the potential for ongoing air exposures, the Maine Department of Environmental Protection and Maine Center for Disease Control and Prevention collaborated on a study to investigate ambient air concentrations of per-and polyfluoroalkyl substances (PFAS) in the area of the AFFF release. An initial sampling took place in November 2024. In April 2025, a second round of testing was conducted to determine whether PFAS concentrations were changing.  Samples were collected when wind conditions were considered favorable for collection sites being impacted by wind from known soil and surface water contamination. Ambient air samples were collected using high-volume active samplers deployed for 72 hours. PFAS bound to particulate matter was collected onto a quartz-fiber filter, and a PUF/XAD-2/PUF media was used to collect PFAS present in the nanoparticle or gaseous phase. Air samples were analyzed at SGS AXYS in British Columbia for a suite of 30 PFAS using isotope dilution LC/MS-MS. A total of five 72-hour ambient air samples were collected at the former BNAS for PFAS analysis. An additional 72-hour ambient air sample was collected in Acadia National Park in Bar Harbor to better understand background levels of PFAS in ambient air without a known PFAS source. There was good agreement with duplicate ambient air samples that were collocated and collected at one of the BNAS sampling locations. At the former BNAS, individual PFAS results for the samples collected in November 2024 ranged from 1 to 70 picograms per cubic meter of air (pg/m3) with the higher results found for PFBA, 6:2 FTS, PFHxA, PFOS, and PFOA. Measured levels were substantially lower for the samples collected in April 2025 with all PFAS other than PFBA detected at less than 10 pg/m3. Results from the April 2025 BNAS sampling were similar to results from sampling ambient air at Acadia National Park. There were differences among individual PFAS in the proportion of mass collected on the quartz filter versus the PUF/XAD-2 resin. For PFOA, generally equal amounts were found on the quartz filter and the PUF/XAD-2 resin. Other shorter chain PFAS were predominately detected in the PUF/XAD-2 resin. For PFOS, the percent recovered from the quartz fiber filter decreased from nearly 50% in November 2024 BNAS samples to approximately 25% in the April 2025 samples. For the Acadia site, the percent of PFOA and PFOS detected on the quartz filter was approximately 50% and 6%, respectively.

This investigation demonstrated it was feasible to sample ambient air for PFAS and detect low pg/m3 levels and monitor changes in air levels over time at an AFFF spill site. The collection methods were capable of partitioning  PFAS into a particle bound phase and either nanoparticle or gaseous phase.

The State of Maine was recently authorized by statute to establish maximum levels for PFAS in farm products. Food consumption rates are needed to provide the scientific basis for setting such levels. The Maine Center for Disease Control and Prevention (Maine CDC) previously used the United States Department of Agriculture’s (USDA) Food Patterns Equivalent Database (FPED) to calculate estimated consumption rates for milk and beef when developing action levels for these foods in 2017 and 2020, respectively. Since that time, the United States Food and Drug Administration (FDA) released its own Food Disaggregation Database (FDA-FDD) for the specific purpose of facilitating chemical exposure assessment for individual foods. In contrast, USDA’s FPED was developed to assess the nutritional quality of Americans’ diets. When linked by USDA food code to National Health and Nutrition Examination Survey (NHANES) dietary intake data, both FPED and FDA-FDD can be used to estimate individual-level consumption rates for foods within each database. We compared consumption rates for milk and beef, plus six additional foods (eggs, lettuce, pork, potato, spinach, and yogurt), calculated using FPED versus FDA-FDD data sets combined with NHANES data for the 2005-2006 through 2017-2018 survey cycles. FPED or FDA-FDD data sets were merged with NHANES individual food frequency survey data, as well as with NHANES demographics and body measures data. We calculated food consumption rates as the two-day mean grams of food per kilograms of body weight for consumers only (i.e., food consumption reported on one or both survey days). We estimated 90th percentile consumption rates for child (0-6 years) and adult (20+ years) populations using the “survey” package in R to account for the complex NHANES survey design. We found the 90th percentile beef consumption rate for children was 12% higher using FPED than FDA-FDD, while the consumption rate for adults differed by only 1%. 90th percentile milk consumption rates differed by less than 5% for both children and adults. When considering other foods, consumption rate estimates were generally higher using FPED than FDA-FDD. The starkest contrast was for spinach, with a consumption rate 65% higher for adults and nearly 3 times higher for children using FPED data. Using standard risk assessment calculations, maximum PFAS levels in foods are inversely proportional to food consumption rates. Therefore, our analysis demonstrates that the choice of database used for calculating food consumption rates can lead to as much as a 2-fold difference in maximum PFAS levels for some foods.

Per- and polyfluoroalkyl substances (PFAS) are widely used for their chemical stability and omniphobic properties, resulting in their pervasive presence in the environment and finished consumer products. Recent medical research highlights significant health risks associated with PFAS exposure in humans and animals. Global regulatory efforts, advocacy from industry associations such as INDA and EDANA, and initiatives by individual brands have driven progress toward reducing or eliminating PFAS in absorbent hygiene products (AHP). A 2023 study, analyzing menstrual products from 2020–2022, detected PFAS in nearly half of the samples. Coupled with evidence of transdermal absorption of PFAS, these findings raise concerns about potential health risks from contaminated products. This talk examines the key risks associated with the presence of contaminants in these products and presents a strategy for assessing levels of contaminants, exploring the difference between “tested” and “certified” PFAS-free product claims.

Currently the FDA uses method C-010.03 for the detection of PFAS in food and feed and the USDA uses method CLG-PFAS 2.04 for the detection of PFAS in cattle, swine, poultry and Siluriformes muscle and cattle plasma.  Between the two federal agencies, there is overlap on the matrices analyzed for research and regulatory purposes.  In order to have consistency and agreement among federal agencies, a new method was developed by USDA-ARS, USDA-FSIS, and FDA scientists.  This method focuses on the priority food matrices which are of interest to both agencies, including milk, eggs, muscle tissue, and seafood.  The analytical method and validation results will be presented.

The Delaware Department of Natural Resources and Environmental Control (DNREC) has launched a comprehensive PFAS investigation and mitigation initiative in the Piedmont region, a geologically distinct area with vulnerable groundwater and surface water systems and legacy industrial activity. This project integrates multi-phase sampling, hydrogeologic modeling, and community engagement to address emerging PFAS contamination in public and private water supplies. Our presentation will include a description of our targeted sampling approach, integrating data from groundwater, surface water, thermal imaging surveys, and borehole geophysics. We will discuss the preliminary observations in PFAS profiles in different media and locations, risk communication approaches, and our interagency approach to this issue. DNREC’s adaptive management framework emphasizes transparency, equity, and science-based decision-making, offering a replicable model for other states confronting similar challenges.

This presentation will share lessons learned, data visualization tools, and potential policy implications for regional PFAS response strategies.

The Massachusetts Toxics Use Reduction Institute (TURI) addresses PFAS pollution by integrating research, policy, and technical support. TURI aims to reduce or eliminate PFAS use while ensuring regulatory compliance and offering resources to industries, communities, and policymakers.

TURI collaborates with researchers and industries to develop safer alternatives to PFAS across various applications:

• Functional Textile Coatings: TURI supports the development of PFAS-free liquid-repellent coatings, which provide comparable performance for textiles in apparel, automotive upholstery, and protective gear.
• Surfactants for Semiconductors: TURI has advanced PFAS-free surfactants for semiconductor etching processes. These alternatives match the performance of PFAS-based surfactants and offer significant cost savings while ensuring compatibility with acidic solutions and long shelf life.
• Refrigerants and Heat Transfer Fluids: TURI evaluated safer alternatives to F-gases in refrigeration and PFAS-containing liquid heat transfer fluids for high-performance computing. Research highlights concerns regarding volatile PFAS exposure, trifluoroacetic acid (TFA) byproducts, and global warming potential. Viable non-F-gas options include CO2 systems, propane (with safety standards allowing indoor use), ammonia for industrial applications, and solid-state technologies. These market-ready alternatives provide operational savings, enabling adoption in supermarkets, warehouses, and household appliances.
• Food Packaging: TURI is testing biobased coatings that provide water—and oil-repellent properties to offer a sustainable alternative to PFAS-based coatings with comparable performance to commercial products.
• Solvents: Some flashpoint inerted solvents (e.g., transDCE) contain PFAS. TURI’s lab work identifying safer solvents supports replacing these PFAS-laden options.
• Emerging Focus Areas: TURI is exploring supply chain mapping and PFAS use in electronics components. Additionally, TURI conducts cost-benefit analyses to evaluate transition strategies, helping industries adopt safer alternatives economically.

TURI plays a critical role in shaping PFAS-related policies in MA:

• Defining PFAS: In collaboration with the TURA Science Advisory Board, TURI helps establish PFAS regulatory categories to ensure clear guidelines for identification and regulation.
• Business Support: TURI guides businesses on identifying, tracking, and reporting PFAS use, ensuring compliance with state and federal regulations.
• Industry Research: TURI investigates PFAS applications in industries such as metal finishing, electronics, textiles, and refrigeration, providing data to inform regulatory decisions.

TURI extends its efforts to promote PFAS alternatives in community settings:

• Artificial Turf: TURI promotes PFAS-free artificial turf in schools or methods that preserve natural grass fields, reducing children exposure risks.
• Firefighting: TURI provided technical and financial support to reduce PFAS in firefighter gear, collaborating with unions for PFAS-free PPE by 2027.
• Community Detection Tools: TURI funded particle-induced gamma emission (PIGE) for total fluorine detection (limit ≈10 ppm) in cosmetics, children’s products, plastics, and water samples. This enables communities and organizations to sort and identify PFAS sources.

TURI’s approach to PFAS pollution is proactive, emphasizing safer alternatives, informed policies, and community solutions. By supporting businesses, researchers, and policymakers with technical data, TURI promotes eliminating hazardous PFAS while ensuring functionality and economic viability.

Limited research has been conducted related to investigation and analytical methods to characterize per- and polyfluoroalkyl substances (PFAS) in fractured bedrock.  Unlike volatile organic compounds (VOCs), there is limited understanding on how sample collection, preparation, extraction, analysis methods influence the interpretation of PFAS transport and fate in bedrock.  Further, the phase relationship of PFAS in bedrock/porewater is not well understood.  This presentation will provide a summary of the application and modification of the COREDFN sampling and analysis methodology to inform the phase relationship and related occurrence of PFAS in bedrock groundwater at a site with a known comingled VOC and PFAS groundwater contamination plume in the northeastern United States.

In order to quantify the concentrations PFAS in pore water of the bedrock, there were necessary adaptations from the COREDFN sampling and extraction methods typically used for VOCs. Supplies, equipment, and sampling were modified to use materials compatible with PFAS sampling. Two extraction methods were compared including a conventional time-series extraction approach and a more time-efficient cryogenic milling method.  The results of this comparison validated application of the cryogenic milling method for most of the samples.

In contrast with well-established methods used for VOC partitioning assessment, there is significant uncertainty in what factors dominate solid-liquid partitioning of PFAS in rock. An experimental/empirical partitioning coefficient (Kd) approach was used, where Site-specific Kd values were derived from batch tests using crushed rock and reagent water. Physiochemical properties of bedrock were analyzed and compared to evaluate potential key factors for adsorption (e.g., TOC, pH, exchange capacity). The Kd values were then used to calculate PFAS rock matrix porewater concentrations that could be used for evaluating transport and fate of PFAS in fractured rock. These data were incorporated into the Conceptual Site Model (CSM) and were instrumental to inform the design of a remediation strategy.

Throughout northeastern Massachusetts, PFAS have been found in public and private water supplies in areas with no readily apparent industrial or historical source. Concentrations in these wells are significant, often exceeding the Massachusetts MCL for PFAS6, and it was suspected that the PFAS may originate from residential septic systems given (1) the lack of evidence pointing to other source contributions and (2) other studies confirming PFAS is present in residential wastewater. To better understand the potential impacts of septic systems on PFAS concentrations in water supplies, field investigations were conducted in two residential areas with impacted water supplies and no sewer service. In both areas, direct push wells were installed to evaluate PFAS concentrations and compositions in shallow groundwater; PFAS were detected up to 54 ng/L PFAS6 and the composition was consistent with nearby water supply wells. The results suggest that residential wastewater may be an important source of PFAS to public and private water supplies in some areas.

These data were compared to Massachusetts-wide datasets of PFAS in public water supplies, private wells, and surface waters to identify other waters that may be impacted by residential wastewater. Similar chemical signatures were observed throughout the state, in surface water, shallow overburden wells, and bedrock wells, indicating the potential for widespread impacts, particularly in dense areas with no or incomplete sewer systems.

The study has important implications regarding treatment (at the receptor vs. at the source) and plume delineation for discrete sources located in areas with a high density of on-property residential wastewater disposal systems. In particular, the relative proportion of short-chain PFAS may be useful for differentiating residential wastewater PFAS from legacy sources.

Per- and poly-fluoroalkyl substances (PFAS) pose serious environmental health risks. Aqueous Film-Forming Foams (AFFF), a major source of PFAS environmental contamination, are being replaced by Fluorine-Free Foams (FFF). Hundreds of FFF have entered the market, many with limited chemical and toxicological characterization and no understanding of their behavior under fire conditions and associated thermal degradation products (TDP).

Objective: To characterize the chemical composition of new FFF foams, including PFAS content, surfactants, and other additives, and investigate their thermal degradation behavior and byproducts.

Twenty-two FFF products were obtained from their original containers at various firefighting stations. The foams were characterized for PFAS using targeted and untargeted analysis, total fluorine content, as well as matrix composition (e.g. surfactants, corrosion inhibitors, and antimicrobial agents). An optimized experimental testing platform was used to study thermal degradation behavior and physicochemical transformations of 7 FFF products under controlled conditions from 25°C - 800°C (10°C/min) in an O2-rich environment (21%). Emissions were characterized using real-time instruments for nano aerosol number, size, and mass distribution as a function of temperature, as well as HF gas, toxic gases CO, SO2, NO, and volatile organic compounds (VOCs). Integrated sampling characterized PFAS mass size distribution, reactive oxygen species (ROS) generation, 12 aldehydes and ketones, as well as foam matrix components using a suite of instruments and analytical methods. One-hour-aged aerosols were investigated for similar endpoints. FFF foams and their TDPs were compared and studied in the context of PFAS content and their profiles.

Targeted analysis detected two PFAS in 5/22 FFF (0.04-0.5ppm total), while 17 other FFF did not contain PFAS. In untargeted analysis, 3-5 PFAS were identified in 21 FFFs, while one product had no PFAS across all tests. In 18/22 FFF, total organic fluorine (TOF) ranged from 0.05-262ppm, with five FFF containing over 40ppm. Supply chain contamination was a likely source of their PFAS in most cases, though for at least five products, PFAS was likely added intentionally. TDP of FFF-produced nano aerosols with a median particle size of 13-90nm. We also quantified 14 matrix components in the foams and aerosol phase, including surfactants, corrosion inhibitors, and antimicrobial agents, which varied between classes of analytes and FFF foams. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyl compounds in all foams. Toxic gases released during combustion included CO, SO₂ & NO, while HF and ROS were not detected.

A direct comparison of replacement FFFs with conventional AFFF foams favors FFF replacements as notably safer alternatives, even though our data suggest that ‘safer’ does not necessarily equate to ‘safe.’

Private well water testing for PFAS is expensive with costs ranging from $250 to $500 for an individual test from commercial laboratories accredited by the State of Maine. This cost can be a barrier for many homeowners wanting to test their well water for PFAS. The company Cyclopure provides a $79 PFAS water testing kit and is easily purchased online directly from the company. However, the Cyclopure test kit sampling procedure and analytical method are not accredited methods for PFAS analysis by the State of Maine. To date, there are limited published data on how well Cyclopure PFAS water test results compare with standard water sample collection methods and PFAS analysis following well accepted, published analytical methods for drinking water. To help fill this data gap the Maine Center for Disease Control and Prevention (Maine CDC) in collaboration with the Maine Department of Environmental Protection (Maine DEP) are collecting paired well water samples at 25 homes in Maine using standard well water collection methods and the Cyclopure test kit collection method. The PFAS analyses were conducted by a commercial lab accredited by the State of Maine and Cyclopure. Homes were identified where Maine DEP previously tested and found levels of PFHxS, PFOS, PFHpA, PFOA, PFNA, or PFDA either individually or the sum of >20 part per trillion (ppt) and were part of ongoing, routine well water testing. Homes were selected where prior testing had identified PFAS water concentrations for the sum of these six PFAS ranging from 20 to >1000 ppt. An additional set of five homes were selected with PFAS well water test results <20 ppt. Homes were selected that had both a mix of PFAS in their well water and a mix of potability parameters (e.g., pH, Fe, Mn). As part of Maine DEP’s ongoing well water testing for PFAS at these homes, a water sample was collected before entering any treatment system and sent to Pace Analytical. PFAS were measured at Pace using their lab developed isotope dilution method based on the EPA 537 method for drinking water. Immediately following the collection of the standard water sample a Cyclopure test kit sample was collected and shipped to Cyclopure for PFAS measurement. Initial results from testing 6 homes found relative percent differences between Pace and Cyclopure measured levels of PFOS and PFOA ranging from 0.5 to 26% and 4 to 43%, respectively, with results for Cyclopure consistently lower. Similar results were obtained for PFHxs, PFHpA, PFNA, and PFDA. For short chain PFCAs the Cyclopure results were also consistently lower. RPDs ranged from 102 to 161% for PFBA, 46 to 85% for PFPeA, and 18 to 98% for PFHxA. These data will be used to help inform responses to homeowners who test their well water using a Cyclopure test and whether additional PFAS water testing may be warranted.

The provision of alternate water supplies (AWS) to prevent exposure is a vital component of our work at NYS Department of Environmental Conservation (NYSDEC) – Division of Environmental Remediation (DER). However, the pervasiveness of PFAS contamination in the environment has caused DER to re-examine when, and under what circumstances, AWS is provided as part of our remedial program. Based on our understanding of PFAS in the environment and NYSDEC’s statutory/ regulatory limitations, NYS needs another resource to assist private well owners with background PFAS contamination in drinking water (i.e., PFAS contamination unrelated to an industrial source).

As a pilot program, NYS (collectively NYS Department of Health, NYS Environmental Facilities Corporation, and NYSDEC) will offer PFAS testing to private well owners in participating counties at no cost. Based on the testing results, owners will be eligible for a mitigation rebate from the county: up to $5000 for a point-of-entry treatment (POET) system or $10,000 for connection to a municipal public water supply, if available. The program will also provide up to $1500 to owners where NYSDEC formerly installed and maintained a POET or point-of-use treatment (POUT) system based on an exceedance of PFAS Maximum Contaminant Levels (MCLs), but an industrial source could not be established.

DEC developed criteria to evaluate risk to background PFAS in groundwater, including relative population density and the presence of private wastewater treatment (septic), sole source aquifers, and disadvantaged communities. These criteria were applied statewide to identify counties to target for participation in the pilot program. We will review how our understanding of PFAS in groundwater evolved over the past 10 years from a remedial perspective, why the program is needed, and how the program works.

Learning Objectives

• Provide an overview of how alternate water supplies are provided at NYSDEC and the impact of PFAS.
• The ubiquity of PFAS in the environment has put private well owners in NYS at greater risk.
• Private well owners in NYS need another resource to mitigate exposure to PFAS outside of NYSDEC’s remedial program.
•  NYSDEC developed criteria to evaluate risk to private well owners from background PFAS contamination.
• Describe the pilot program and how it's administered.

Please join us for a light breakfast and refreshments from 8-8:30 AM (provided).

Within the last few years, the PFAS treatment and destruction technology market has expanded significantly, offering owners new options for PFAS-impacted residuals management in addition to traditional disposal means (e.g., permitted landfills, solidification, deep well injection). Selecting a destruction technology for PFAS-impacted waste management can prevent the material from reentering the environment (e.g., landfill leachate) and eliminate long-term liability for the waste owner. There are well over a dozen (and counting) distinct destruction technologies available. These technologies span a range of commercial readiness from bench-scale with limited case studies, to rigorous testing at the bench, pilot, and commercial-scale. The objective of this discussion is to identify several developing and commercial PFAS treatment and destruction technologies and provide an overview of previous and ongoing projects that focus on demonstrating the destruction removal efficiency (DRE) and economic viability of the technologies for different matrices (i.e. leachate, wastewater, groundwater, AFFF). The technologies to be highlighted and discussed include foam fractionation, supercritical water oxidation (SCWO), hydrothermal alkaline treatment (HALT), electrochemical oxidation (EO), photochemical/UV, electron beam, sonolysis, Galvanic/Electrolytic Cell, and non-thermal plasma.

Recent case studies and projects from the last year 2024-2025 will be shared to provide data and state of maturity in the market for these different technologies and different vendors of each technology type. Case studies that will be discussed include:

• Case Study 1 - Defense Innovation Unit (DIU) and ESTCP awarded projects for onsite field demonstrations to evaluate supercritical water oxidation (SCWO) and hydrothermal alkaline treatment (HALT) to treat several matrices including foamate, media regenerant still Bottoms, spent GAC, spent IX, and AFFF
• Case Study 2 - Department of Defense (DoD) funded project for field demonstration of SCWO, HALT, and sonolysis to treat AFFF.
• Case Study 3 – Commercial Landfill Leachate – Foam Fractionation treatment and destruction of foamate pilot testing by SCWO, HALT, plasma, electrochemical oxidation, photochemical/UV, electron beam, and sonolysis.
• Case Study 4 – Foam transition and decontamination destruction bench testing of rinsate and spent cleaning agents with sonolysis, electrochemical oxidation, photochemical, plasma, Galvanic/Electrolytic Cell.

This presentation will provide an overview on innovative PFAS treatment and destruction approaches from various technology vendors while using real world case studies to provide data and status on their maturity and use in the industry. A main takeaway is to recognize that the “best” treatment approach is often site specific and requires a treatment train approach of various technologies for successful PFAS treatment and waste management overall.

TRS Group (TRS) has completed three field demonstrations, using thermal conduction heating (TCH) to treat PFAS contaminated soil. TCH involves heating steel casings inserted into soil to hundreds of degrees Celsius (⁰ C). The heat propagates from the casings, heating the surrounding soil, volatilizing PFAS, which is then captured and treated.

The field demonstrations include:

• Treatment of an existing soil pile at Eielson Air Force Base
• In situ treatment of soil in a fire-training area at Beale Air Force Base
• Treatment in an engineered soil pile at Joint Base Elmendorf Richardson (JBER)

TRS has demonstrated the effectiveness of PFAS thermal desorption at temperatures between 350 and 700⁰ C, most recently at JBER near Anchorage, Alaska. Incorporating lessons from earlier demonstrations, TRS heated 2,000 cubic yards of soil over three months to an average temperature of 638⁰ C. To evaluate performance, 30 soil samples were collected- all showed PFAS concentrations below USEPA and Alaska DEC soil criteria. The combined sample was non-detect for all targeted PFAS, analyzed by EPA Method 1633.

A total of 710,000 kilowatt-hours (kWh) of energy were applied to the soil stockpile, which equates to 355 kWh/yd3- which is low compared to other thermal solutions. An analysis completed by the US Navy TRS’s treatment at Beale AFB more sustainable than alternatives such as excavation, off-site disposal, or incineration. Vapors were treated via cooling, condensation and filtration, meeting all local air and water discharge requirements.

Thermal treatment works for all soil fractions, including fine particles like clay and silt, construction debris, asphalt and concrete. Final waste is minimal, mostly composed of spent activated carbon, which can be regenerated or destroyed Nearly all treatment equipment components can be reused or recycled.

Public water systems (PWS) across the United States, especially smaller and rural communities, face significant challenges in addressing per- and polyfluoroalkyl substances (PFAS) contamination under the U.S. Environmental Protection Agency’s new National Primary Drinking Water Regulation (NPDWR). With maximum contaminant levels (MCLs) as low as 4 ppt and compliance required by 2031, utilities must identify effective and sustainable treatment strategies quickly. Four best available technologies (BATs), granular activated carbon (GAC), ion exchange (IX), nanofiltration (NF), and reverse osmosis (RO), are widely used to remove PFAS, but each has unique trade-offs in cost, energy and media use, waste generation, and operational complexity. Existing guidance tools are either too generalized or require detailed engineering design, creating barriers for many resource-limited systems. To bridge this gap, we are developing a streamlined, interactive decision-support tool that allows utilities to compare PFAS treatment options with minimal input data. Built on robust statistical analysis of more than 300 design and operational parameters and validated through extensive Monte Carlo simulations (160,000 trials), the tool distills critical drivers of treatment performance, including flow rate, GAC bed contact time, number of redundant filters, and backwash intervals, into a simplified decision framework. This approach enables utilities to assess upfront and lifetime costs, energy demand, and filter media use while transparently highlighting environmental and operational trade-offs. Unlike prior comprehensive but cumbersome spreadsheet-based decision tools, this application, designed in Microsoft PowerBI and hosted at the University of Maine, the tool emphasizes usability and accessibility. Partnerships with the Maine Water Utilities Association and Maine Rural Water Association provide direct feedback from PWS stakeholders, ensuring the tool meets real-world needs. This presentation will highlight tool development, case study applications from Maine systems with high PFAS levels, and expected benefits including reduced costs, lower energy and material consumption, and improved decision-making capacity. The project provides an urgently needed resource to support science-based, sustainable PFAS treatment decisions that protect both public health and the environment.

Keywords: PFAS treatment technologies, Decision-support tool, Public water systems (PWS), Sustainable treatment selection, Cost and energy optimization

Perfluorooctane sulfonic acid (PFOS) is an anthropogenic chemical found in aqueous film-forming foams (AFFFs) and many consumer products. Despite its environmental ubiquity and persistence, little is known about the effects of PFOS on stress levels in wild animals. Here, we examined PFOS bioaccumulation and correlations between PFOS exposure and oxidative stress in snapping turtles (Chelydra serpentina) downstream of Griffiss Air Force Base in Rome, New York, a known source of AFFF contamination. Maximum concentrations of PFOS were extrapolated as 41.7 ppb and 498 ppb in water and turtle samples, respectively; in comparison, the proposed United States national advisory concentration of PFOS in drinking water is currently 0.00002 ppb. PFOS concentrations declined with distance downstream from the base and were lower in other local water bodies. Indices of oxidative stress were positively correlated with plasma PFOS concentrations in snapping turtles. These data illuminate the potential for bioaccumulation and increasing oxidative stress levels associated with PFOS contamination in a wild population of aquatic turtles.

Freshwater turtles can be important bioindicators of aquatic pollutants because of their longevity and wide- spread distribution, moreover, because of their restricted home-range and highly aquatic habits, their chemical profile likely reflects contamination in the local aquatic environment. AFFFs are a source of PFAS contamination with long-

term, global implications for wildlife health, including the elevated oxidative stress that we report in this study.

Global environmental contamination has been caused by the use of AFFF at military bases, fire departments, and

airports and PFAS concentrations in surface and ground waters around these sites can be millions of times higher than health advisory concentrations. By some estimates, it can take more than 1000 years for PFAS to biodegrade under normal soil conditions. Given the persistence of existing contamination in the environment, PFAS is likely to have long-term consequences for the health of aquatic wildlife and humans in AFFF contamination sites.

The land application of treated wastewater solids (biosolids) as fertilizer has led to contamination of agricultural sites with persistent organic chemicals that are not removed during wastewater treatment, including per- and polyfluoroalkyl substances (PFAS). Over a 40-year span (1978–2018), over 2 million cubic yards of biosolids were applied as soil amendments to more than 1,300 licensed agricultural fields in Maine. While several studies have examined PFAS accumulation in beef and fish, there is a notable lack of data on poultry and eggs as dietary exposure sources. We assess soil-to-egg PFAS transfer on a farm and homestead with two distinct contamination profiles: one dominated by perfluorooctane sulfonate (PFOS), a legacy compound and current regulatory focus, and another characterized by elevated levels of fluorotelomer precursors, which remain unregulated. We also measure PFAS concentrations in feed, water, vegetation, and earthworms to evaluate additional exposure pathways contributing to PFAS uptake in poultry. To complement targeted PFAS measurements, we construct an organofluorine mass balance to identify the fraction of total extractable organofluorine (EOF) not accounted for by commonly monitored compounds. Preliminary results indicate the abundant presence of ultra-short-chain PFAS, including trifluoroacetic acid (TFA), in exposure sources and eggs, highlighting the need to broaden monitoring efforts beyond legacy targets such as PFOS. The ultra-short-chain PFAS were found in all feed, water, soil, and egg samples suggesting a widespread presence and not solely related to biosolids-contaminated soil. By examining both direct and indirect exposure routes, and comparing measured versus unidentified organofluorine, this work aims to inform the development of risk-based soil screening values to support farmers in evaluating land suitability for poultry production and identifying effective mitigation strategies.

Per- and polyfluoroalkyl substances (PFAS) have been shown to bioaccumulate in fish.  Bioconcentration factors have been computed for certain PFAS in laboratory studies with controlled doses of PFAS, however it is uncertain if wild fish experience similar bioaccumulation rates.   Field studies including PFAS measurements in water and fish have also been used to compute bioaccumulation factors (BAFs), however many aspects of the waterbodies and wild fish are inherently variable.  The current study examined PFAS bioaccumulation of hatchery-raised brook trout that were stocked in the late fall in two small ponds with high concentrations of PFAS in the water.  The age of the fish and duration of exposure were controlled but the fish were in a natural environment rather than a laboratory setting.  Two age classes of trout were included in the study, including fall fingerlings (½ year old) and fall yearlings (1 ½ year old).  Fish and water samples were collected before stocking and 1, 2, 4, and 10 weeks after stocking.  In addition, passive PFAS samplers were deployed in one of the ponds. Twenty-eight kinds of PFAS were analyzed for the fish and water samples.  The PFAS with the highest concentrations in the fish included PFOS, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, and PFOSA.  PFOSA and PFUnDA had the highest BAFs.  The yearling trout had lower concentrations of PFAS and lower BAFs compared to the younger, fingerling trout.  Fish collected later in the study had higher PFAS concentrations and BAFs than fish collected earlier in the study.  The BAFs observed in this study were generally less than BAFs computed in other studies, perhaps due to the cold water and short duration of the study.  BAFs were also computed with the passive sampler data.  Overall, this study demonstrated that brook trout that are stocked in waterbodies with high concentrations of PFAS can rapidly accumulate unsafe levels of PFAS.  A “do not eat” fish consumption advisory was issued for the ponds.

Per- and poly-fluoroalkyl substances (PFAS) have impacted hundreds of private drinking water wells across Washington state. In rural areas, the same well water that people drink is often used to water chickens, cows and pigs raised for personal consumption. Studies in other states and countries have shown that livestock with dietary exposure to PFAS can have contaminated meat, milk, and eggs. Residents in two rural communities with PFAS-contaminated well water (East Selah, Yakima County and West Plains, Spokane County) asked the Washington State Department of Health (WDOH) to evaluate the safety of consuming their home-raised livestock.

Between December 2023 and April 2025, WDOH collected 74 samples from home-raised livestock for food safety evaluation, including 20 samples of meats (beef, pork, chicken, turkey), 45 samples of chicken and duck eggs, and plasma from 8 beef cattle. Samples were analyzed for 16-18 PFAS by the US Department of Agriculture, Food Safety Inspection Service using their method CLG-PFAS 2.04, or by Enthalpy Analytical lab using EPA method 1633. The 36 participating households had PFAS contamination in their drinking water wells ranging from less than 10 parts per trillion (ppt) to over 1000 ppt with PFOS and PFHxS predominating.  WDOH applied the approach we use to set fish consumption advisories to develop household consumption advice based on food sample results. We used a conservative serum/meat ratio of 9.1 when estimating PFOS in meat from PFOS serum results in live beef cattle. We also included advice about how to reduce PFAS in the foods, including switching animals to clean water and moving poultry to new ground. We offered limited retesting after action was taken to track the efficacy of our recommendations.

PFOS and PFHxS were frequently detected in chicken and duck eggs and less frequently in poultry meat, pork and beef. Other PFAS were infrequently detected. A majority of participating households were advised to reduce their average weekly consumption of at least one home-raised food until PFAS levels in food were lowered. Specifically, 80% of the households that provided eggs and 25% of households that provided a meat sample or had live cows tested for PFAS, had a test result that prompted a recommended consumption limit. Estimated human exposure from regular ingestion of the tested foods was comparable or higher than that from ingesting drinking water at state and federal drinking water action levels. Retesting showed that switching to clean water usually reduced levels of PFAS in the foods but also that further investigation and action is needed to restore the safety of these foods for regular human consumption.

Our project demonstrates that meats and eggs can be an important secondary exposure to people living with PFAS contamination in their drinking water supply. Absent national food standards, direct food testing can guide when action is needed to reduce significant human exposures.  There is an urgent need to investigate and mitigate these exposures where PFAS contaminates rural drinking water supplies.

Per- and polyfluoroalkyl substances (PFAS) testing in fish has found them to be nearly ubiquitous, often at concentrations of concern for human consumption. Yet very little is known about concentrations in waterfowl, and whether these concentrations are high enough to pose a concern for human or other wildlife consumers. A large proportion of New York’s waterfowl harvest is associated with the Great Lakes. Ample boat launches and state-owned properties open to waterfowl hunting make the Great Lakes region a premiere destination for waterfowl hunters. Approximately 30% of New York’s mallard and black duck harvest occurs in the counties bordering Lakes Erie and Ontario and the Niagara and St. Lawrence Rivers, even though they represent just 13% of the state’s landmass. In an effort to update consumption advisories, wildlife agencies in NY and PA collected samples of waterfowl during the hunting seasons in 2023 and 2024 and analyzed them for legacy contaminants (e.g., dioxins, mercury, organochlorine pesticides, polychlorinated biphenyls), as well as PFAS. We collected 125 birds from 8 species from the counties bordering Lake Erie, and the New York Counties bordering the Niagara River, Lake Ontario, and the St. Lawrence River. These birds were analyzed for PFAS by SGS-AXYS (Sidney, BC) using USEPA Method 1633. To facilitate the evaluation of risk to human health we primarily analyzed samples of homogenized breast muscle, skin, and fat from each bird. Twenty percent of samples had breast muscle and skin plus fat analyzed separately to assess partitioning between the tissue types. Similar to fish, perfluorooctanesulfonic acid (PFOS) was the most commonly detected PFAS compound, being found in all but one bird. PFOS detections ranged from just above the reporting limit to 53.3 ng/g. While the highest PFOS result was in a Common Goldeneye (Bucephala clangula), concentrations in this species were varied. Both the Red-breasted and Common Mergansers (Mergus serrator and M. merganser, respectively) had more consistently elevated PFOS. The other PFAS compounds most commonly detected in fish (perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnA), and perfluorododecanoic acid (PFDoA)), were regularly detected in these waterfowl, but at substantially lower concentrations than PFOS. The fluorotelomer carboxylate precursor compound, 2H, 2H, 3H, 3H-perfluorodecanoic acid (7:3 FTCA), was detected regularly in Red-breasted Mergansers, sometimes at levels exceeding PFOS. Interestingly, PFOS does not appear to partition strongly between breast muscle and the skin plus fat components, with variable ratios across and within species. Conversely, 7:3 FTCA partitions into the skin plus fat, with paired samples often below detection in breast muscle and elevated in the skin plus fat. This study adds to the growing evidence that PFAS are entering human and wildlife food-chains and should be broadly surveyed, including evaluations of a larger selection of commonly consumed game species.

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and have been identified in livestock, raising concerns about human exposure through food consumption. Laying hens may be exposed to PFAS through contaminated water, soil, or feed. Limited data exist on the bioavailability, absorption, accumulation, distribution, and excretion of PFAS in laying hens during lifetime exposures to environmental levels of PFAS as well as depuration from contaminated birds. The relationship between PFAS intake by laying hens, distribution in tissues, and depuration after lifetime exposure was assessed. Fifty-five layer chicks were exposed to 25 PFAS compounds. The PFAS mixture included 13 perfluorocarboxylic acids (4–18 carbons; PFCA) and 12 perfluorosulfonates (4–13 carbons; PFSA), administered at 100 ng/L each in drinking water from 2 days of age through 32 weeks of age. Birds were harvested periodically (1, 2, 4, 6, 10, 14, 18, 22, 26, 32 weeks) to measure PFAS accumulation in tissues, including plasma, liver, breast and thigh muscle, egg yolk and egg white, followed by a 9-week (33, 35, 38, 41 weeks) depuration to assess decontamination of laying hens. Samples were analyzed using established in-lab methods with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). ƩPFSA and ƩPFCA levels in plasma increased from week 1 to week 18, however at week 18 the levels decreased as egg lay started. Liver had higher concentrations than plasma and showed similar increasing levels until egg lay started at week 18. As observed in other animals, the muscle levels are approximately 10% of the plasma levels in laying hens. Plasma and liver analysis shows that PFSAs of 6-10 carbon chain length are absorbed and accumulated in the plasma and liver of laying hens over 32 weeks of exposure and growth. Currently, kidney, skin, and egg samples are being extracted and analyzed. Preliminary exposure estimates will compare our results with existing reference doses to evaluate whether laying hen tissues and products contribute to overall PFAS exposure in the diet.

PFAS exposure levels and sources among children in communities with contaminated drinking water supplies have been understudied. In communities where PFAS-contaminated drinking water is being treated, there are gaps in understanding the associations of early-life PFAS exposure from drinking water and long-term serum PFAS levels in children and in characterizing non-water PFAS exposure sources specific to children.  The public drinking water supplies serving the Pease Tradeport, NH, and Hyannis and Ayer, MA, previously had elevated PFAS levels, mainly from the use of aqueous film-forming foam (AFFF) at nearby fire training areas. All three water systems have installed filtration to comply with state standards. The aims of this study were to compare serum PFAS levels among children in these communities following water filtration, evaluate how serum PFAS levels have changed over time, and characterize potential ongoing exposure contributions from diet and consumer products.

Between 2021 and 2024, we collected serum samples from 87 children (ages 4-17 years) likely exposed to PFAS from drinking water serving the Pease Tradeport, Hyannis, and Ayer as part of the PFAS-REACH Study and the MA PFAS & Your Health Study. Parents/guardians completed a questionnaire about their child’s duration of time in the study area, drinking water and breast milk consumption history, current dietary behavior, and recent use of PFAS-relevant consumer products. Serum samples were analyzed for 24 targeted PFAS. We compared serum PFAS levels across study communities and developed multivariable linear regressions to evaluate potential associations of serum PFAS with diet and home-based consumer product use.

Twelve PFAS were detected in at least one sample, and three (PFHxS, PFOA, PFOS) were detected in 100% of samples. The median serum level for PFHxS was higher among children in Pease (1.22 ng/mL, IQR: 0.79-1.58 ng/mL) compared to Hyannis (0.99 ng/mL, IQR: 0.78-1.61 ng/mL) and Ayer (0.55 ng/mL, IQR: 0.37-0.91 ng/mL), consistent with the relative levels of historic PFAS contamination among the three water systems. Median levels were similar among the three communities for PFOS (range: 1.91-2.09 ng/mL), PFOA (0.67-0.85 ng/mL) and PFNA (0.15-0.17 ng/mL). Analyses focused on associations of serum PFAS among children in our three communities and diet and consumer product use are ongoing.

For children at Pease, we compared our results to prior community-level blood testing data collected in 2015 by NH DHHS and 2019-2021 by the ATSDR Pease Study. We found that serum levels of PFOS, PFOA, PFHxS and PFNA all decreased. For instance, median serum PFHxS levels among Pease children dropped substantially from 4.24 ng/mL in 2015 to 1.8 ng/mL in 2019-2021 and 1.22 ng/mL in 2023-2024 among our PFAS-REACH participants at Pease. Nevertheless, the median levels of PFHxS from Pease and Hyannis remained higher than children in the general U.S. population based on testing by the CDC from 2017-2020 (0.7 ng/mL), even 4-10 years after PFAS in treatment in drinking water began.

These findings demonstrate the importance of prompt action to address PFAS drinking water contamination and the need to evaluate ongoing non-water PFAS exposures to understand individual and community-level exposures in children.

Co-authors and affiliations:

• Courtney Carignan, Michigan State University
• Abigail Bline, Maine Center for Disease Control and Prevention
• Phil Brown, Northeastern University
• Yuting Wang, Silent Spring Institute
• Emily Heckel, Silent Spring Institute
• Rebecca DeVries, Eastern Research Group
• Tamarra James-Todd, Harvard T.H. Chan School of Public Health
• Marlee Quinn, Harvard T.H. Chan School of Public Health
• Douglas Walker, Emory Rollins School of Public Health
• Laurel Schaider, Silent Spring Institute

The increasing use of biosolids for soil enrichment introduces PFAS into agroecosystems, where they interact with plants, soils, and microbial communities in complex ways that remain poorly understood. While research has largely focused on PFAS mobility and plant uptake, much less is known about their distribution, fractionation, and microbial effects, which are critical insights needed for ecological risk assessment, sustainable management, and regulatory frameworks. This greenhouse study investigated six common PFAS, including PFOA, PFOS, , PFNA, PFHxS, PFBS, and HFPO-DA (GenX), in vegetated soils amended with Class A or Class B biosolids, with emphasis on their distribution, fractionation, and microbial impacts. The results revealed contrasting behaviors between short and long-chain PFAS. Short-chain PFAS were evenly distributed throughout the 8-cm soil column in growth containers, whereas long-chain PFAS accumulated in deeper layers. Sequential soil extraction for PFAS showed that short-chain PFAS dominated the water-leachable fraction, while long-chain PFAS were enriched in the methanol-extractable fraction. Plant cultivation promoted redistribution of long-chain PFAS from the water-leachable to the methanol-extractable fraction, potentially reducing their mobility. Elevated PFBS levels in the alkaline-hydrolysable fraction indicated the release of PFAS precursors from soil organic matter, contributing to enhanced plant uptake of PFBS. Moreover, both biosolid class and PFAS exposure significantly affected soil microbial diversity. Microbial stratification appeared to be linked to vertical PFAS distribution: microbiomes in the upper soil layers were influenced by GenX and PFBS, while PFOA, PFOS, and PFHxS shaped those in the deeper layer. These findings suggest that chemical partitioning directly impacted microbial ecology, with potential consequences for nutrient cycling and soil health. Overall, this work provides insights to inform biosolid land application policies, guide phytoremediation and soil management strategies, and highlight the need to address both regulated PFAS and precursors in regulatory frameworks.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that resist degradation and pose long-term risks to groundwater and receptors. Effective treatment requires addressing both vadose zone soils and the saturated source area to halt ongoing mass discharge. Activated carbon is a promising and widely available adsorbent that effectively immobilizes PFAS, significantly reducing the mass flux of these contaminants.

In this study, a dual format in situ remediation approach using a low dust microaggregate sorbent that combines powdered activated carbon (PAC) with colloidal activated carbon (CAC) and a suspension of micron-scale CAC particles, designed to be applied into the capillary fringe and saturated zones. was mixed into a Northern Michigan site soils to stabilize the soils and prevent PFAS leaching. These CAC based technologies address PFAS in a way that prevents continued plume development and supports long-term retention through a process known as PFAS Enhanced Retention (PER).

The presentation will highlight a field demonstration of the PER approach at a PFAS-impacted military airport site in the Midwest, targeting vadose zone soils and groundwater to immobilize PFAS and reduce leachability. The microaggregate, upon contact with water and soil, rapidly disperses and coats the soil matrix, improving blend uniformity and maximizing contact between the sorbent and PFAS contamination. Our results show over a 99% PFAS reduction in leachability via the synthetic precipitation leaching procedure (SPLP). The data highlight the importance of addressing the capillary fringe within source zones and homogeneous amendment distribution for soil stabilization.  Additionally, the presentation will show >5 years of PFAS concentration reductions in groundwater following the injection of liquid CAC. Overall, our results highlight the significance of the carbon-based in situ treatment in halting PFAS migration

Objective: Epidemiological studies investigating potential links between contaminant exposures from drinking water and adverse outcomes often face challenges due to sparse water concentration data. For emerging contaminants like per- and polyfluoroalkyl substances (PFAS), drinking water measurements are rarely available for >5-10 years, limiting assessments of associations with health outcomes over time. Furthermore, reconstructing exposures among participants is complicated by varying residential histories and water-related behaviors. As part of the Agency for Toxic Substances and Disease Registry’s Multi-Site PFAS Health Study (MSS), we reconstructed historical serum concentrations for individual study participants for perfluorooctanoate (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoate (PFNA).

Methods: The MSS is a cross-sectional epidemiological investigation that enrolled over 5,700 adults (ages 18+) and 700 children (ages 4-17) in communities with a history of PFAS drinking water contamination within eight U.S. states. Participants completed questionnaires (2019-2023) that captured residential histories back to 2000 and water-related behaviors (tap/bottled water, home filtration) and provided blood samples for serum PFAS analysis. As a longitudinal component, historical concentrations of PFAS in drinking water were estimated using hydrogeological and numerical modeling approaches and used to estimate monthly serum concentrations for each participant back to 2000 using a one-compartment pharmacokinetic model. To evaluate model performance, we compared measured concentrations to modeled serum concentrations (matched by month and year).

Results: Geometric mean serum concentrations varied 3- to 7-fold across sites, reflecting differential patterns in water contamination. Historically reconstructed serum concentrations were substantially higher than recent serum measurements, reflecting declining exposures following water remediation and population-level declines in background exposures.

Conclusion: Reconstructed serum levels provide insight into past exposures among study participants within and across sites. Results will be used in ongoing MSS assessments of potential associations of health biomarkers and disease prevalence with chronic PFAS exposure from drinking water over time.

Disclaimer:  These findings and conclusions have not been formally disseminated by the Agency for Toxic Substances and Disease Registry and should not be construed to represent any agency determination or policy.

Co-authors and Affiliations:

• Aaron Maruzzo, Silent Spring Institute
• Scott Bartell, University of California, Irvine
• Claire Lay, Abt Global Inc.
• Meghan Lynch, Abt Global Inc.
• Rachel Rogers, Gradient
• Jason Sautner, Agency for Toxic Substances and Disease Registry
• John Adgate, Colorado School of Public Health
• Abigail Bline, Maine Center for Disease Control and Prevention
• Linda Brown, RTI International
• Weihsueh Chiu, Texas A&M University
• Russ Detwiler, University of California, Irvine
• Tim Fennell, RTI International
• Panos Georgopoulos, Rutgers University
• Yerin Jung, University of Southern California
• Ben Lanava, Harvard T.H. Chan School of Public Health
• Ted Lillys, RTI International
• Xiang Ren, Rutgers University
• Steve Shost, New York State Department of Health
• Joost van ’t Erve, Michigan Department of Health and Human Services
• Brent Windebank, Colorado School of Public Health
• Meghan Weems, Agency for Toxic Substances and Disease Registry
• Marian Pavuk, Agency for Toxic Substances and Disease Registry

As part of Maine’s LD 1600 investigation, the Maine DEP investigated, or contracted environmental professionals to investigate, all sites licensed to land apply septage. This talk (poster) presents a high-level look at PFAS fingerprint patterns in both soil and groundwater derived from analysis of this statewide dataset. The analysis includes soil and groundwater from the spreading area, as applicable, as well as groundwater from off-site receptors around licensed septage land-application areas The scope is intentionally first-pass/descriptive, and is designed to uncover clear, high-level patterns without advanced source apportionment. The goal of this analysis is to make appropriate conclusions from a large dataset that are accessible to policymakers and the public while providing useful analysis for regulators and technical users. The overarching goal of the analysis that has led to this presentation is to better understand how soil and groundwater have been affected by historical septage spreading which occurred at sites within the State of Maine.

We used straightforward steps to harmonize data from multiple laboratories and focused on the consistent treatment of censored results to generate compositional summaries and pattern families based on class (PFCAs, PFSAs, Precursors, FTSs), chain-length, and ratios. We pair these fingerprints with spatial summaries such as counts and rates of detections by distance from Site boundaries and general down-gradient aligning of detections, with contrasts by aquifer and geologic setting, when possible. Graphics are designed to be intuitive to keep the analysis accessible and transparent.

Through a Defense Innovation Unit-funded project, ECT2 designed and built a mobile prototype of a regenerable anion exchange resin (AER) treatment system for PFAS treatment in groundwater and demonstrated it over an 8-month period at the former Naval Air Station Joint Base Willow Grove in Willow Grove, Pennsylvania. Groundwater with high levels of PFAS, up to 50 micrograms per liter, were pumped from an aqueous film forming foam- impacted source area extraction well. Three loading and regeneration cycles were performed and a total of 2.5 million gallons of groundwater were treated. The demonstration showed that groundwater with very high levels of PFAS could be treated to non-detect levels for a wide variety of PFAS; for compounds with USEPA MCLs, bed life was approximately 30,000 bed volumes before breakthrough above MCLs and for PFBA, bed volumes were approximately 7,500 bed volumes before breakthrough above its treatment goal of 100 ng/L. Upon AER bed exhaustion, the vessels were taken offline for 24 hours for PFAS desorption with an alcohol brine solution. Following regeneration, the AER vessels were returned to groundwater treatment and the regeneration solution was distilled to recover alcohol and leave a PFAS-waste concentrate referred to as still bottoms. A process concentration factor of 20,000 was observed, meaning one gallon of PFAS waste concentrate was generated per 20,000 gallons of water treated. The AER was demonstrated to return to virgin conditions after each regeneration cycle, supported by repeatable breakthrough curves for each treatment cycle, non-detect concentrations immediately after regeneration in vessel effluent, and complete recovery of PFAS in the regeneration solution. The high PFAS, low volume regenerant solution was delivered to multiple PFAS destruction companies for demonstration of a complete treatment and destruction solution. A technoeconomic analysis of the regenerable AER product was performed, with comparison in lifecycle costs to single use AER and foam fractionation at varying scales of system sizes.

Drinking water remains an important source of exposure to per- and polyfluoroalkyl substances (PFAS). The National Academies of Sciences, Engineering, and Medicine (NASEM) recently recommended clinical risk thresholds for specific PFAS concentrations in serum. Several authoritative bodies have adopted these recommendations to guide decision-making.  Relating the NASEM clinical thresholds in serum to drinking water levels can allow regulatory bodies to identify and prioritize individuals and communities at high risk due to PFAS in drinking water. With this objective, the Massachusetts Department of Environmental Protection’s Office of Research & Standards (ORS) developed a probabilistic population toxicokinetic (TK) model that predicts the distribution of serum concentrations in defined populations from drinking water concentrations for the six PFAS regulated in MA (perfluorooctanoic acid, perfluorooctane sulfonic acid, perfluorohexane sulfonic acid, perfluorononanoic acid, perfluorodecanoic acid, and perfluoroheptanoic acid). The population PFAS TK model builds from an existing one-compartment probabilistic toxicokinetic model for four PFAS, significantly revising the underlying framework, input distributions, calculation methods and utility. Population distributions for exposure factors and chemical-specific toxicokinetic parameters are combined using Monte Carlo methods to predict population serum PFAS concentrations based on specified drinking water exposures and accounting for transgenerational transfer and exposure from non-drinking water sources. Modeling is implemented in R and uses the integrated rate law to increase computational efficiency and precisely calculate the population distribution of serum PFAS concentrations at any timepoint in the modeling period. Model performance was evaluated using published studies reporting drinking water PFAS concentrations and the observed distribution of serum PFAS concentrations in the study population. Modeled serum PFAS concentrations were within two-fold of the observed concentrations for studies with different age populations, PFAS, exposure concentrations, and for populations in different geographic regions. The population PFAS TK model was implemented to calculate drinking water concentrations for six PFAS that maintained serum PFAS concentrations below NASEM clinical guidance thresholds for sensitive populations. Important drivers of the resulting clinical guidance-based drinking water concentrations include half-life and ability to transfer via breastmilk. The population PFAS TK model is a useful tool that can support regulatory decision making by relating drinking water levels to clinical guidance thresholds for serum in a population.

This project aimed to conduct targeted analyses of per- and polyfluoroalkyl substances (PFAS) in the Delaware and Schuylkill Rivers. Water samples were collected from several locations and analyzed using the EPA 1633 method for PFAS. The results indicate the widespread presence of various PFAS compounds, with PFBA, 6:2 FTS, PFOA, and PFOS being the most abundant in the Schuylkill River, detected at nearly all sampling locations. In the Delaware River, the prevalent compounds shifted from PFTeDA, PFTrDA, and PFDS in 2019 to 6:2 FTS and PFOA in 2021. Factors such as population density, proximity to industrial sites, and other pollution sources appear to influence these distribution patterns, particularly as concentrations of targeted PFAS compounds increase from Pottstown in the Schuylkill River and Trenton in the Delaware River toward central Philadelphia. Risk assessments, based on EPA advisory levels for PFOA and PFOS, using the Risk Quotient method and proposed Hazard Index, revealed that at least 60% of samples from both rivers presented a medium risk profile according to 2016 EPA guidelines, while 70% of samples fell into the high-risk category under 2024 EPA regulations. This evaluation is crucial, as both rivers are sources of drinking water and serve multiple wastewater and water treatment facilities.

Foam Fractionation has emerged as a leading method of removing PFAS from water. Utilizing rising bubbles of gas, particularly ambient air, foam fractionation takes advantage of PFAS’s amphiphilic properties to temporarily bind PFAS to the air-water interface of rising bubbles which may be collected as they separate from water. This method allows for efficient capture of PFAS without the use of solid media. Surface Active Foam Fractionation (SAFF®) is a commercially available implementation of foam fractionation that has been tested at numerous sites.

Different subject waters necessitate differing approaches non-PFAS constituents that can affect PFAS removal rates during foam fractionation. SAFF® has been used to successfully remove PFAS from many different water sources. PFAS removal rates, volumetric waste concentration factors, and throughput vary across water types due to differences in water chemistry and co-contaminants. For example, landfill leachate has much higher total dissolved solids (TDS) and biochemical oxygen demand (BOD) than other waters, resulting in more rapid foam production and the need for enhanced foam management. Reverse osmosis (RO) reject water has high TDS but is lacking in many of the other organics present in landfill leachate, resulting in better bubble integrity which can effect PFAS removal. Within these two matrices high variances can occur.

Allonnia (Boston MA) has collected significant data on foam fractionation of leachate, groundwater, RO Reject, stormwater, and process water during SAFF® deployments. This study aims to compare PFAS removal, foam production, and volumetric concentration across different water types. Allonnia is the distributor of SAFF® in North America.

This presentation will review trends in EPA’s Chemical Data Reporting (CDR) data for PFAS production and import and compare the chemicals reported to CDR to those included in EPA’s published test methods and the chemicals actually found in environmental sampling. The presentation will also include qualitative review of the CDR trends.

Every four years, US manufacturers and importers must report data including the manufacture or import quantity (together, “production volume”) for each chemical the company manufactures or imports. We reviewed six cycles of CDR data, dating back to the 1998 IUR, to assess changes in the PFAS chemicals reported over time. Compared to non-PFAS chemicals, qualitative assessment shows much more churn in PFAS reporting (i.e., chemicals are less likely to continue to be reported year over year). For instance, only 38% of new PFAS chemicals reported in the 2016 CDR were reported in the 2020 CDR, compared to 57% for all chemicals.

CDR data were compared to validated EPA test methods such as the drinking water test method 537.1. Many PFAS produced in large volumes are not included in validated test methods. For example, production of 1H,1H,2H,2H-perfluorooctyl iodide was reported by 6 sites in the 2016 CDR, with national production volume between 1 and 10 million pounds, but this PFAS is not included in Method 537.1 or Method 8372.

While the identity of PFAS reported in the environment depends on existing test methods, there remain notable differences in PFAS reported in the environment and in production even considering the limitations of existing test methods. Two known reasons for this phenomenon are legacy contamination, such as past use of fire fighting foams containing PFOS and PFOA, and degradation of PFAS in the environment to more stable metabolites such as PFBS.

This session will also incorporate data from EPA’s Toxics Release Inventory (TRI). TRI requires covered facilities to report on releases or disposal of any of nearly 200 covered PFAS. Facilities use available data sources such as SDSs and other supplier notifications to identify chemicals for TRI reporting, so TRI data are not contingent on the existence of test methods. TRI data can help to further identify gaps in test methods, based on the individual chemicals that facilities report disposing of or otherwise releasing to the environment.

Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants of emerging concern in agricultural systems, with legacy land application of biosolids leaving soils in many regions highly impacted. While ingestion of food and water is generally recognized as the primary route of PFAS exposure, airborne transfer of PFAS-laden soil particles during agricultural activities remains a critical knowledge gap. Farmers and farmworkers frequently disturb soils through tillage, creating conditions for particle entrainment and inhalation exposure. Bulk soil PFAS concentrations are commonly used in exposure assessments, yet these measures may underrepresent PFAS concentrations in the specific particle size fractions most relevant to dust generation, atmospheric transport, and respiratory uptake. Smaller particles, enriched in organic matter, are both more likely to sorb PFAS and to remain airborne. Addressing this gap is essential for accurate risk assessment and management of contaminated agricultural lands.

To close some of these knowledge gaps, the FLOAT project investigates the distribution of PFAS across soil particle size fractions and their potential for airborne transfer under conditions simulating farm operations. In a greenhouse study, we conducted controlled tillage of a PFAS-contaminated agricultural soil and measured airborne particles over a 24-hour period. Dust was captured using multiple complementary approaches: (1) passive dry deposition samplers to integrate across total suspended material; (2) active high-volume samplers collecting total suspended particles (<100 µm) on quartz filters with downstream polyurethane foam (PUF) or resin to capture fine particles and semi-volatile compounds; and (3) a PM2.5 selective sampler isolating respirable fine particles (<2.5 µm). Together, these methods provide a comprehensive picture of PFAS occurrence across particle sizes and phases (solid vs. vapor).

In a second phase, bulk soils from multiple PFAS-contaminated agricultural sites were dry-sieved into fractions (<65 µm, 65–125 µm, 125–500 µm, and 500–2000 µm) to quantify PFAS content as a function of particle size. This fractionation directly tests the hypothesis that smaller particles are enriched in PFAS due to elevated organic matter content and surface area, and thus more relevant to airborne transfer and off-site movement. Comparing these results across soils with contrasting textures and organic matter provides the basis to extrapolate findings beyond the initial study site.

PFAS concentrations in bulk soils and their particle-size fractions across multiple soil types will be presented. Furthermore, PFAS concentrations in airborne particulate matter following simulated tillage, as well as a comparison of passive and active air sampling strategies for characterizing agricultural dust, will be discussed. These data will inform exposure assessments for farmers, improve modeling of PFAS movement from agricultural land via wind, and provide new parameters for PFAS fate and transport models. More broadly, this work highlights the importance of understanding media transfer between soils and air, and demonstrates the value of integrating soil characterization, particle-size distribution, and air sampling into PFAS site assessments to advance knowledge of environmental fate and transport in agricultural contexts.

As federal and state regulators begin to implement or evaluate PFAS effluent discharge limitations and biosolids regulations, the landscape for wastewater utilities is rapidly evolving. These changes are driven by forthcoming updates to the U.S. EPA’s Effluent Limitation Guidelines (ELGs) and a growing emphasis on contaminants such as nutrients, PFAS, microplastics, and other emerging contaminants. In response, utilities are progressively adopting forensic tools to not only characterize influent sources but also trace pollutant pathways and develop cost-effective treatment strategies.

This presentation will provide a national and local update on the current regulatory status of ELGs. It will delve into key drivers behind proposed revisions to these guidelines and highlight significant state-level actions. The session will then explore how wastewater utilities can leverage forensic tools, ranging from advanced chemical analysis to sophisticated data-analytical methods, to proactively prepare for and respond to these evolving standards.

Attendees of this session will gain insights into several cutting-edge techniques. The role of compound-specific isotope analysis, chemical fingerprinting, and high-resolution mass spectrometry will be examined, illustrating how these methods can effectively identify sources of PFAS and other emerging contaminants. Furthermore, the presentation will discuss the application of statistical and machine learning models that enable the correlation of influent trends with industrial discharge patterns, offering a deeper understanding of pollutant dynamics.

The use of wastewater-based source tracking will be highlighted as a strategic tool to support pretreatment programs and load reduction planning. This approach not only aids in regulatory compliance but also may enhance operational efficiency of wastewater treatment processes. Case studies highlighting where forensic methods have been successfully employed will be discussed.

In addition to technical insights, the session will address how forensic findings can play a crucial role in improving communications. Due to the large number of potential sources of PFAS, it can be important for entities to differentiate among discrete releases of PFAS. While some PFAS, like PFOS and PFOA, have been used in many different applications, distinguishing among different sources of PFAS can be accomplished using a multiple-lines-of-evidence approach.

This presentation will educate attendees with a comprehensive understanding of the current regulatory landscape and innovative forensic tools available to help them prepare for future regulations. Enhancing public transparency and trust enhances better relationships with stakeholders and builds resilience in their operations. By embracing these methodologies, wastewater utilities can navigate the complexities of regulatory compliance and drive towards sustainable, resilient operational practices.

In 2023, NYSDEC issued final ambient water quality guidance values for PFOA and PFOS for the protection of human health and aquatic life, along with a supplemental guidance document which established how the guidance values are applied to State Pollutant Discharge Elimination System (SPDES) permits to optimize environmental protection and minimize financial impacts (Technical Operational Guidance Series (TOGS) 1.3.13: “Industrial Permitting Strategy for Implementing Guidance Values for PFOA, PFOS, and 1,4-Dioxane”). The guidance outlines NYSDEC’s prioritization strategy, focusing on industries with both the greatest potential to have these emerging contaminants present in their wastewater, and those most likely to impact human health.

In addition to the guidance implementing actions to control industrial discharges, NYSDEC will finalize guidance this year to address emerging contaminants discharged through Publicly Owned Treatment Works (POTWs).

This presentation will focus on NYSDEC Division of Water’s emerging contaminant policies and the implementation of strategies in SPDES permits to reduce discharges of PFAS to waters of the state. An overview of monitoring results and source control efforts will also be discussed.

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals known for their environmental persistence, bioaccumulation, and potential toxicity. Due to widespread use in industrial and consumer applications, PFAS are commonly detected in soil, water, and biota. To support regulatory efforts the New York State Department of Environmental Conservation (NYSDEC) conducted a statewide assessment to develop anthropogenic background threshold values (BTVs) for PFAS in rural soils. The study involved the collection of 548 soil samples from 116 rural properties, using a design consistent with NYSDEC’s 2005 Rural Soil Survey. Sample types included 232 source-distant, 232 remote, 58 near-source, and 26 field duplicate samples, collected from two depth intervals: 0–2 inches and 2–12 inches. Samples were analyzed for 40 PFAS compounds using USEPA Draft Method 1633, with data validated according to NYSDEC DER-10, USEPA Region II, and NYSDEC PFAS guidance. After removing duplicates and invalid results, statistical evaluations were conducted by combining sample types within each depth interval to represent rural population exposures. Summary statistics were compiled for all 40 analytes, including sample counts, percent nondetects (NDs), concentration ranges, and reporting limits. PFAS were detected above reporting limits for 19 analytes in 0–2 inch samples and 25 analytes in 2–12 inch samples. Analytes with ≤85% nondetects were retained, resulting in 9 (0–2 inch) and 8 (2–12 inch) analytes for BTV development. Distribution testing and outlier analysis were conducted using USEPA ProUCL Version 5.2. Goodness-of-fit (GOF) tests were used to identify appropriate statistical distributions (normal, gamma, or lognormal), with nonparametric methods applied when no fit was found. To confirm that data reflected diffuse anthropogenic background, an environmental forensic analysis using principal component analysis (PCA) and hierarchical clustering was performed. This confirmed the absence of point-source clustering and validated the dataset’s use for background characterization. BTVs were calculated using the 95% upper tolerance limit with 95% coverage (UTL95_95), along with UPLs and upper percentiles. Censored data were addressed using the Kaplan-Meier method.

Recommended BTVs for two key PFAS include:

•    PFOS: 3.000 µg/kg (0–2 in), 0.801 µg/kg (2–12 in)

•    PFOA: 1.500 µg/kg (0–2 in), 1.200 µg/kg (2–12 in)

With EPA and state interest in reducing PFAS in wastewater treatment plant biosolids and effluent discharges to the environment, wastewater treatment plants (WWTPs) need to identify viable and cost-effective strategies to maintain sustainable operations and reduce long-term liability.

The most efficient approach involves targeting PFAS at point sources, where volumes are limited but concentrations are elevated as opposed to treating the WWTP effluent and biosolids. This strategy can include pre-treating PFAS in industrial discharges before they reach WWTPs—either at the industrial facility in alignment with Industrial Pretreatment Permit requirements, or at the WWTP for hauled-in wastewaters, with appropriate surcharges applied. Specifically, pre-treatment of landfill leachate is an effective strategy, as it represents a significant PFAS source for many WWTPs; a 2021 U.S. EPA study identified PFAS in 95% of surveyed landfill leachate samples. The pre-treatment of these point sources effectively reduce PFAS entering the WWTPs and by extension, the PFAS levels in biosolids and discharged effluents.

This presentation details the execution of a successful onsite pilot campaign utilizing a closed-loop PFAS removal, concentration, and destruction treatment train at a municipal WWTP in the Northeastern United States. The project focuses on evaluating pre-treatment strategies for landfill leachate that is hauled-in to the facility. Additionally, the presentation will provide performance data, compare various operating conditions, and address challenges encountered during the onsite implementation, emphasizing key insights now informing the development of a full-scale commercial system design.

The demonstrated treatment train uses Foam Fractionation (FF) to remove and concentrate PFAS, followed by Electro-Oxidation (EO) for their destruction. FF leverages PFAS's surfactant properties to separate and concentrate them as foamate, which is then fed into EO—a proven, energy-efficient onsite method for PFAS breakdown. The treated EO effluent is then returned to the FF unit for further processing, resulting in a cost-effective, closed-loop PFAS removal, concentration and destruction solution.

The most proactive and cost-effective approach to preventing impacts associated with the release of PFAS is to raise user awareness to enable and encourage businesses to reduce the use of these materials. This sounds basic and most would assume that this has been accomplished, however over the past two years I have visited multiple industrial facilities ranging from small to Fortune 100 facilities and found that none of facilities had attempted to identify PFAS in their supply chain or chemical inventory. In most cases, site leadership and EHS teams were not familiar with what PFAS were or the concern associated with these materials. This finding suggests current outreach efforts merit modification to better connect with PFAS users.

The following options for raising awareness and supporting change will be reviewed:

1.    All agencies and organizations responsible for the management, disposal or treatment of PFAS should review and modify their public outreach to better target PFAS users. These entities should actively ask businesses if they are using PFAS during each communication or encounter. Where possible, industry or audience specific messaging should be developed. Opportunities for information sharing should be identified and promoted.

2.    Federal regulations require manufacturers and distributors to inform consumers if their products contain PFAS. Most businesses are not aware of this requirement. Businesses should be instructed how they could use this tool to screen their chemical inventories and supply chains for PFAS. An effective approach is to list this requirement on a purchase order when purchasing chemicals and requiring the submittal of certificate of analysis to demonstrate the product is free of PFAS. This places the cost and responsibility on the supplier to demonstrate the product is PFAS free.

3.    Regulatory agencies and NGOs should work together to spotlight specific PFAS products that have widespread use is specific industrial sectors and where alternatives are readily available. Common examples include portable fire extinguishers containing AFFF are consistently found in facilities using flammable liquids, and Trifluoroacetic Acid (TFA) which is commonly used in HPLC analysis by the healthcare and life science can easily be replaced using less toxic reagents. Cleaning compounds have numerous industrial applications and pose another opportunity for promoting change both by the user and the manufacturer. Efforts should be made to create a public listing of commercial products found to contain PFAS so that others can consult the list.

4.    Financial cost or risk often motivates change. Many insurance companies have adopted PFAS limits or exclusions to their pollution liability insurance policies. As a result, facilities may have limited or no coverage for PFAS releases. This can be a valuable talking point because production managers are not always aware of terms of their insurance coverage. A lack of coverage could motivate a facility to reconsider its chemical usage.

These suggestions could help organizations tasked with managing PFAS releases and impacts to better educate and inform the users of these materials while also offering strategies that could allow industrial users to reduce the use of these materials.

From 2023-2025, the New Jersey Department of Environmental Protection (NJDEP) conducted a statewide soil study to evaluate per- and polyfluoroalkyl substance (PFAS) occurrence, fate, and transport. The primary goal of this study was to investigate potential PFAS soil impacts due to atmospheric deposition. A total of 157 samples were collected from surficial soils (0-6 inches below ground surface) in all 21 New Jersey counties at locations spatially distant from known PFAS contamination or presumptive sources of potential PFAS contamination. Samples were analyzed for 40 PFAS compounds using EPA Method 1633. In addition, the synthetic precipitation leaching procedure (SPLP) was used to evaluate contaminant leachability and assess the potential for current PFAS levels in soil to impact co-located ground water.

In total, 23 PFAS compounds were detected in at least one sample and 17 PFAS compounds were not detected in any sample. Perfluoroundecanoic acid (PFUnA) (98.7%), perfluorooctane sulfonic acid (PFOS) (98.1%), perfluorodecanoic acid (PFDA) (97.5%), perfluorononanoic acid (PFNA) (96.2%), and perfluorooctanoic acid (PFOA) (94.3%) were the most frequently detected compounds. The composition and sum of total PFAS varied significantly across the state (Figure 1), with statistically significant differences in individual PFAS concentrations identified between many counties indicating the presence of localized areas with greater impacts. A statistically significant increase in PFAS concentration was also observed in urban areas relative to rural areas for certain longer-chain PFAS compounds.

SPLP results were used to calculate sample-specific soil-water partitioning coefficients (Kd values) and evaluate the migration to ground water exposure pathway. Compound-specific Kd values were found to vary by many orders of magnitude, suggesting that differences in soil type can have a large impact on PFAS retention in soils. Lastly, PFAS concentration results were compared to the results from studies conducted by other states in the northeast United States and to NJDEP’s interim soil remediation standards for PFOA, PFNA, PFOS, and hexafluoropropylene oxide dimer acid and its ammonium salt (Gen-X chemicals).

The results from this study were published in a report on the NJDEP website on September 15, 2025.

Wastewater treatment plants (WWTPs) are recognized as sources of PFAS releases to surface water. Landfill leachate is suspected to be one of the most significant sources of PFAS loading into WWTPs. EPA is studying pretreatment requirements under its Plan 15 effluents guidelines program. However, some research/investigations have shown that landfill leachate may only contribute to small portions of the total input. Identifying feasible and cost-effective treatment technologies for the overall WWTP influent can be challenging due to the plant size and water chemistry. Further, in the case study examined, despite frequent sampling of PFAS in WWTP influent, effluent, and sewer systems, the mass balance, transport, and transformation of PFAS through WWTP units—especially digesters—remain not fully understood.

A comprehensive investigation was implemented for landfill leachate and the associated WWTP receiving the leachate in March 2025. Multiple innovative methodologies were employed to assess overall PFAS transport:

•    PFAS analysis (using methods 1633 and 8421) and chemical characterization of landfill leachate were performed under both high- and low-flow conditions to evaluate variation due to precipitation.

•    For the sewer system and WWTP process units, 72-hour composite samples were collected for PFAS and chemical characterization to capture the variability, rather than grab samples.

•    PFAS and chemical profiles were evaluated for all WWTP units (Figure 1). Aerobic digester sampling included vertical profiling, foam, and aerosol collection. Aerosol samples were taken using mesh-framed baskets filled with sorbent sampling media placed above the digester. Fluorotelomer alcohols (FTOH), also present in leachate and landfill gases, were analyzed to track their transport and transformation.

The results quantified the contribution of PFAS loading from different sources to the overall influent of the WWTP and provided the basis for the strategies of reducing WWTP loading and PFAS treatment.

•    Mass Balance: During periods of low and high leachate flow events, PFAS from landfill leachate comprised more than 90% and less than 50%, respectively, of the total PFAS load entering WWTP. Septic sludge represented the second largest PFAS source to the WWTP. Biosolids exhibited elevated concentrations of PFAS, particularly long-chain compounds such as PFOA, PFOS, and FTCA. The PFAS mass in biosolids constituted 40% of the total PFAS loading into the WWTP (Figure 2). The PFAS mass contained in biosolids and effluent was approximately equivalent to the total influent PFAS mass.

•    PFAS Transformation: Differences in PFAS composition were observed between the effluent and influent of the WWTP, with the septic sludge indicating a high potential for precursor transformation. The aerobic digester converted precursors to regulated PFAS such as PFOA, PFHxS, and PFOS. Samples from the post clarifier contained negligible amounts of precursor compounds. FTOH results are pending while preliminary data indicate both active transformation and volatilization in the aerobic digester.

•    Treatment Considerations: Leachate treatment can be crucial in reducing PFAS loading and effluent concentrations. Foams collected from the anoxic tank and aerobic digester contained PFOA and PFOS at levels 1000 times higher than those in the influent, indicating that foam removal may be a practical method for reducing effluent levels.

EPA’s PFAS Analytic Tools provide a powerful resource for examining publicly available PFAS data across the United States. Developed by Eastern Research Group (ERG) in collaboration with EPA, this place-based platform integrates information from EPA, states, Tribes, and localities to support understanding of where PFAS have been manufactured, released, managed as wastes, and detected in the environment. This session will offer a practical update on recent enhancements to the tools, including expanded datasets related to drinking water, surface water, fish tissue, and Clean Water Act permitting and water quality impairments (ERG anticipates these will be loaded by the time of the Conference). Presenters will share tips for navigating the tools effectively, explain the tools’ relevance and value for water quality decision-making, describe opportunities to contribute additional information, and discuss important limitations and caveats.

We will explore how the tools have evolved over time and what the data reveal about where PFAS contamination is occurring, how geographic coverage has shifted, and where important gaps remain. A focused analysis of drinking water data will include trends observed through UCMR 5 and any more recent additions, as well as discuss coverage of small and Tribal systems.  We will also share insights that help contextualize EPA’s announced revisions to the final PFAS drinking water rule—offering a preview of what’s next for drinking water protection. Environmental sampling data—including fish tissue sampling results—will be examined alongside Clean Water Act datasets to help attendees identify patterns in PFAS exposure, understand whether these patterns relate to permitting and impairment decisions, and evaluate how environmental data can inform regulatory and monitoring strategies. We’ll share case studies and illustrative examples of how EPA’s PFAS Analytic Tools have been—and could be—used to identify potential sources of contamination, support local decision-making and stakeholder engagement, and identify data gaps.

By the end of this session, participants will be able to:

•    Navigate EPA’s PFAS Analytic Tools to locate and interpret PFAS data relevant to their community or region.

•    Identify key data sources and recent enhancements, including updates related to drinking water, environmental sampling, and Clean Water Act programs.

•    Understand data limitations and gaps, and recognize opportunities to contribute additional data to improve national PFAS mapping

•    Apply insights from the Analytic Tools to support local research and decision-making.

Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic compounds known for their environmental persistence, bio-accumulative nature, and widespread detection in aquatic environments. To evaluate the extent and magnitude of PFAS contamination in Massachusetts, the Watershed Planning Program within the Massachusetts Department of Environmental Protection (MassDEP) conducted a study in the summer and fall of 2024 to investigate PFAS concentrations at 10 freshwater and 26 coastal locations. Most sampling locations in the study were selected based on proximity to known or suspected PFAS sources, but sites also included five “reference” waterbodies not near to known sources. Freshwater samples consisted of whole fish (41), fish filets (33), composite invertebrates (45), and surface water (10). Coastal samples included fish filets (89), composite shellfish (81 from 380 individual specimens), and surface water (27). Samples were analyzed for 40 PFAS using EPA Method 1633A.

Study data were analyzed by sample type and PFAS analyte. In addition, PFAS concentrations were compared across several variables, including waterbody characteristics (e.g., region, reference versus non-reference) and sample characteristics (e.g., species). The contribution of individual PFAS analytes to the total PFAS detected in a sample were examined for surface water and biota. Where possible, bioaccumulation factors were calculated using co-located tissue and surface water samples for a subset of PFAS detected in both media. Sample results were also compared to final recommended ambient water quality criteria (AWQC) and benchmarks for the protection of aquatic life, and draft recommended AWQC for the protection of human health, both published by the U.S. Environmental Protection Agency, as well as screening values from the Massachusetts Department of Public Health. Overall, this study confirms the widespread presence of PFAS in Massachusetts surface waters and aquatic biota, with generally higher concentrations observed in freshwater systems and near known sources. The findings underscore the importance of bioaccumulation in aquatic organisms and enable preliminary evaluation of associated risks to aquatic life and human health.

There is significant confusion regarding the validity and applicability of various analytical techniques for assessing per- and polyfluoroalkyl substances (PFAS) in consumer products. Specifically, the type and scope of information provided by commonly used PFAS-related analytical assays, both individually and in combination, have not been thoroughly evaluated using consumer product examples. Although reviews of these methodologies exist, no study has translated their theoretical capabilities into practical applications using real-world products (Md et al. 2020).

TRC, in partnership with Pace® Analytical Services, performed a study that aimed to quantify PFAS and fluorine content in three distinct consumer products using total fluorine, total inorganic fluoride, solvent extraction, and leachate analyses to assess PFAS presence and bioavailability of PFAS to consumers.  To maximize public relevance and the likelihood of detecting measurable PFAS concentrations, we selected consumer products that have been alleged in recent media reports for potential PFAS content.  By comparing results across these assays, we will present the strengths and limitations of each method and assess how data interpretation varies depending on the analytical approach used. Leachate analyses will be used to evaluate arguments surrounding polymeric vs. nonpolymeric PFAS (i.e., what remains bound in a matrix vs. what is bioavailable to us).  It will allow us to evaluate if PFAS detection necessarily indicates PFAS exposure or risks to human health.

Understanding the results of this study will be critical as PFAS-related litigation on consumer products continues to escalate. Given the ongoing debate over which PFAS testing methods are legally and scientifically defensible, our presentation may be usable as a precedent and will include a well-documented understanding of method limitations and analytical challenges of consumer products.  Part of the presentation will include a discussion of why a multi-method approach may be necessary for risk assessment in some contexts.

Md, Zahra S, Yanju L, Raja D, Sreenivasulu C, Ravi N, et al. 2020. Recent advances in the analysis of per- and polyfluoroalkyl substances (PFAS)—A review. Environmental Technology & Innovation. 19: 100879.

The Texas Commission on Environmental Quality (TCEQ) has been a leader in addressing environmental contamination by various per- and polyfluoroalkyl substances (PFAS). In response to PFAS measured at one of the sites in the TCEQ remediation program, in 2011 the TCEQ developed reference doses for 16 PFAS that were used to derive protective concentration levels (PCLs) for various environmental media. In February 2023, TCEQ updated the reference doses (RfDs) for 3 of these PFAS chemicals, primarily based on recent derivations conducted by the U.S. Environmental Protection Agency. Currently, TCEQ is in the process of systematically updating toxicity factors for the remaining 13 PFAS.

Using the procedures outlined in the TCEQ Guidelines for Developing Toxicity Factors, TCEQ derives toxicity factors and documents the derivation by providing the scientific background, rationale, and details of the dose-response assessment that forms the basis of chemical-specific toxicity factors. TCEQ staff will discuss the derivation of the toxicity factor values for two of these PFAS: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). TCEQ toxicologists will outline the systematic review process, available evidence, and steps used for deriving RfDs for these PFAS. These RfDs will be used to update environmental media-specific (e.g., soil, groundwater) values for use with screening and cleanup of remediation sites in Texas. These cleanup levels are being applied to the more than 50 sites in Texas that have PFAS contamination. TCEQ will also discuss data on the occurrence of PFAS in public drinking water in Texas that was collected as part of EPA’s fifth Unregulated Contaminant Monitoring Rule (UCMR5).

Per- and polyfluoroalkyl substances (PFAS) are of forefront concern by regulatory agencies. The long-term stability, environmental pervasiveness, and health effects of PFAS occurring at relatively low concentrations make environmental characterization a high priority. The New York State Department of Environmental Conservation (NYSDEC) Division of Water began its ambient surface water monitoring program in 2022 to better understand the types and concentrations of PFAS observed within the State’s lakes and streams. Here NYSDEC evaluates effectiveness of two monitoring designs weighted at different spatial scales: a basin-scale design versus a statewide scale design. Due to uncertain PFAS occurrence and variability, two monitoring strategies were investigated to better understand the necessary scale and sample frequency needed to adequately estimate PFAS regionally.  While a basin-scale design provides a better understanding of local conditions, it is significantly more resource intensive, requiring more sites, cost, and staff compared to a statewide design. A full basin schedule would require a 5-year cycle to capture all 17 major drainage basins in NYS. In contrast, a statewide design, would characterize patterns over a 2-year timeframe reducing cost and staff time but at a less localized scale.  While a statewide scale is preferable for efficiency, it may not adequately estimate predominant trends if there is considerable basin to basin variability. For both designs, monitoring sites were selected using a probability-based approach weighted by Strahler order (streams) and waterbody area (lakes) to estimate PFAS.  Each year sample collection occurred between June and October as single site visits at approximately 40 lake and 40 stream sites using EPA Method 1633 to measure 40 PFAS. Basin-scale monitoring occurred in 2022 and 2023, where we sampled three different drainage basins each year. Statewide scale monitoring occurred in 2024 and 2025. Overall PFAS findings were similar across spatial designs, where more than half of the 40 chemicals examined were never detected in the environment above applicable reporting limits. The most frequently detected chemicals included PFBA, PFOA, PFOS, PFBS, PFHpA, and PFHxA. These detections were frequently observed at very low concentrations near or slightly below reporting limits. All PFOA and PFOS observations were below the NYSDEC guidance values protective of aquatic life (fishing) and only a few sites had detections slightly above the guidance values protective of drinking water sources. Our findings indicate that PFAS found in lakes and streams generally occur at low concentrations and that a statewide design is a rapid, cost-effective means to estimate PFAS in ambient surface waters. These findings will help inform future PFAS priorities and assessment strategies.

Granular activated carbon (GAC) anionic exchange resin (IX), and surface-modified clay, e.g., Fluoro-sorb (FS) are regularly used for PFAS removal.  As more PFAS systems are being designed, utilizing long duration and expensive field pilots becomes impractical.  Rapid Small-scale Column Tests (RSSCTs) have been around for several decades and were developed around the use of GAC as the adsorbent and more conventional organic compounds as the adsorbate.  Recently RSSCTs have become more accepted for use in PFAS applications but are often considered a screening step preceding a field-scale pilot.  Moreover, they are generally recognized as useful for comparative media performance but often lack confidence to accurately predict field-scale performance.  Moreover, there is more comfort with utilizing RSSCTs for GAC, and less comfort with using RSSCTs for IX or FS.

Of concern is the lack of standardization of RSSCT designs.  Current approaches to RSSCT designs and operation have evolved past the only available standardized methodology (ASTM D6586) which was not developed with trace contaminants such as PFAS in mind.  Furthermore, it is exclusively focused on GAC and does not address using RSSCTs for other relevant size-reducible media.  It is important to recognize that published papers utilize different designs and configurations and may not provide adequate similitude.

As such it is important to identify key design parameters to maintain consistency between tests.   This presentation will discuss key aspects of design including RSSCT scale factor, use of hydrodynamic relationships through Sherwood, Schmidt and Reynolds numbers, and physical dimensions (related to column diameter, depth, and media particle size and distributions).  A description of why each parameter is important and how to best design the RSSCT will be discussed.

When implementing these tests, assembling the RSSCT set-up in a specific way is important.  Specifically, practice of prefiltration is not consistent.  Some arrangements have negated pre-filtration which is problematic given increasingly smaller media sizes used in RSSCTs.  The lack of pre-filtration increases the probability of column clogging or flowrates not being maintained, which can invalidate testing. Moreover, specific to PFAS, the common practice of bulk pre-filtration has shown to be problematic due to loss of long-chain sulfonates across the filter.   More consistent results have been observed with in-line filtration.  However, a pre-saturation step must be conducted.  A detailed presentation of pre-filtration data will be provided and discussed.  A recommended methodology for filter pre-saturation will be presented.

Lastly, there are recently published means to provide refined scale-up of the data, which will be discussed with project examples.  These include approaches such as scale-factor corrections for GAC (Hopkins & Knappe 2024) hydrodynamic corrections for IX (Cheng & Knappe 2024).  Example results using published data from combined RSSCT / field-scale projects (Pannu et al, 2023; Medina et. al. 2022) and Water Research Project (WRF) 5153 will be provided to show paired RSSCT and field-scale data with correction factors applied.

Elevated PFOS concentrations in soil, feed, and milk have been measured at several Maine dairy farms with historical biosolids application. In 2020, Maine CDC developed soil screening levels (SSLs) for land used to grow feed for dairy cattle using an existing U.S. EPA model that incorporates contaminant transfer from soil to plants, cattle feed intake, incidental soil ingestion while grazing, and contaminant transfer from feed intake to milk. Maine CDC is updating these SSLs in response to expanded and Maine-specific data on PFOS uptake in grass-based forages and corn, and PFOS transfer from contaminated feed into milk.  Expanded data on PFOS transfer from soil to plants includes recently published data on grass-based forages (Simones et al. 2024) and new data from co-located sampling of soil and corn harvested as silage and snaplage, with mean soil-to-plant transfer factors of 0.13 (SD 0.1) for grasses, 0.06 (SD 0.04) for corn silage, and 0.008 (SD 0.008) for corn snaplage. Published data on PFOS transfer from feed to cow’s milk are limited and variable. At a Maine dairy farm with relatively stable, low level PFOS milk levels resulting from feed grown in contaminated soils, monthly paired feed and milk samples were collected over a three-month period to derive a mean PFOS intake-to-milk transfer factor of 0.025 day/kg (SD 0.007). Other SSL model inputs were set to U.S. EPA default values or adjusted to reflect Maine agricultural practices. SSLs were derived for three farming scenarios: 1) a 100% grass-fed farm, 2) a mixed diet of grass-based forage, corn silage, and grain, and 3) a diet including corn snaplage as a grain replacement. Each crop-specific SSL assumes any additional feed does not contain any PFOS. SSLs were calculated for each farming scenario as a function of a range of target PFOS milk levels. The upper milk limit was based on Maine’s current action level for PFOS in milk of 210 ng/L, and the lower limit was based on the current commercial laboratory method reporting limit of 24 ng/L. Resulting SSLs ranged from 0.3 to 2.9 ng/g for grass-based forage, 2.3 to 20 ng/g for corn silage, and 27 to 232 ng/g for corn snaplage. Data from a Maine dairy farm where cattle graze on contaminated land were used to check model performance with inputs adjusted to account for available farm-specific exposure information. Using the average soil-to-grass transfer factor of 0.13, the model-estimated PFOS milk were 7 to 8-fold greater than measured levels. Adjusting to a site-specific plant transfer factor near the low end of values reported by Simones et al. (2024) resulted in model-estimated PFOS milk levels within 2-fold of measured levels. These SSLs are intended as a preliminary evaluation tool for dairy farms with elevated PFOS soil levels to determine when further site-specific assessment is recommended, allowing for continued model refinement with site-specific data.

Per- and polyfluoroalkyl substances (PFAS) are persistent manufactured contaminants of growing concern for both environmental and human health. Due to their ability to partition into both aqueous and carbon-rich matrices such as sediment and tissue, their concentration and distribution can vary greatly in the environment. In Maine, many widely-studied terrestrial PFAS sources such as farmland biosolid application can ultimately impact coastal water quality and estuary organisms through riverine transport.  However, there is limited understanding of the transport and fate of PFAS in estuarine and coastal environments across the state. To address this knowledge gap, three comprehensive PFAS sampling campaigns across more than 90 sites in different seasons within Maine’s Casco Bay Estuary were completed, with the ultimate goal to characterize spatial and temporal PFAS patterns and gain insights into potential PFAS sources. In response to an aqueous film-forming foam (AFFF) spill at the former Brunswick Naval Air Base, select stations in Harpswell Cove were sampled more frequently over the course of one year. All samples were analyzed using EPA Method 1633. PFAS were detected at all sampling locations across the bay, with distinct source-specific composition patterns present at river mouths and the AFFF spill site. In rivers, legacy compounds such as PFOA and PFOS were present in the highest concentration, followed by PFHpA and PFHxA. Using our data, we estimated the importance of various sources for PFAS inputs into Casco Bay. PFAS input via wastewater treatment plants appears to contribute very minimally to the overall input of PFAS in the bay, while other non-point sources entering the rivers, such as upstream agricultural or landfill runoff, seem to dominate. The detailed monitoring around the spill site enabled the tracking of the AFFF-related PFAS transport through the impacted bay. Samples near the spill site exhibited elevated levels of 6:2 FTS, a compound associated with AFFF, which was only detected at trace levels at other sites. This finding suggests that this compound can be used as a tracer for the spill. Furthermore, our results also showed a relatively fast dynamic of a pulse of PFAS moving through Harpswell Cove. Concentrations at five stations along a transect up to 10 miles from the spill peaked at approximately 10-100 times pre-spill concentration. About three months after the spill, concentrations returned to pre-spill levels, primarily due to tidally-driven gradual dilution. Overall, this study is the first of its kind in Maine to investigate PFAS at a large scale in the coastal environment. Additionally, this study highlights the value of comprehensive sampling surveys to provide information for PFAS exposure assessment and source control in coastal ecosystems.

The ongoing regulatory scrutiny of PFASs has been focused on the use of fluorosurfactants in firefighting foams, with regulatory action to phase the products out in most of the world. Understanding the self-assembly of amphiphilic PFASs and their propensity to form highly stable supramolecular assemblies sheds light on mechanisms by which they attach to surfaces within fire suppression systems. Multilayered supramolecular assemblies comprise concentrated forms of crystalline PFASs which require removal as part of fire suppression system decontamination to prevent significant rebound of PFASs into F3 foams. Current challenges transitioning to F3 foams include decontamination of PFASs from within fire suppression systems, with reports showing rebound of up to 1.6 g/L PFASs into F3 foam following a double water rinse of the fire suppression system.

All fluorinated firefighting foam contain fluorosurfactants (i.e., polyfluoroalkyl PFASs) for which there are no analytical standards. As the vast majority of PFASs in firefighting foams are not detected using targeted chemical analytical methods (i.e., USEPA Method 1633A), a more comprehensive approach is required to prove fire suppression system decontamination has been effective. As a result of a detailed understanding of how PFASs attach to surfaces in the form of supramolecular assemblies, a surface swabbing method and chemical analytical method for detection PFAS on non-porous surfaces has been developed.

Swabbing is done repeatedly within a 100 cm2 area and are extracted using a sequential base-acid approach that has been proven on soils. The analytical method includes the Total Oxidisable Precursor (TOP) assay, to provide assurance that both per- and polyfluoroalkyl PFASs present in firefighting foams can be detected. The triple swabbing method has been shown to be effective for assessment of PFASs impacted pipework by measuring the total elemental content of the pipe surfaces using Time of Flight Elastic Recoil Detection (TOF-ERD). The difference in surface elemental composition of PFAS-impacted pipework on an area that had been swabbed using this method compared to an unswabbed area demonstrated that the swabs remove over 95% of the fluorine associated with the pipe surface. The swabbing procedure, extraction approach, and analytical method were tested and shown to be effective for assessment of PFASs on surfaces. The method is now commercially available and quantifies PFASs on the inner surface of fire suppression systems to validate that equipment decontamination has been successful.

Recent full scale decontamination projects have established that some fire suppression system components can be effectively decontaminated as proven using the surface swab data. Swab samples collected after decontamination by vendors using proprietary solutions shows significant PFASs remaining on the interior of fire suppression systems. This presentation will discuss the concerns of incomplete PFASs decontamination of equipment that currently and/or historically contain(ed) PFAS-containing fire fighting foam. The initial focus will be on published results of supramolecular structures coating the wetted interiors of fire suppression systems. A discussion on the insufficient characterization of water rinses will be presented, supported by analytical results from field-scale decontamination efforts. Lastly, side-by-side comparisons of decontamination data incorporating the swab method described herein will demonstrate the risks.