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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.’

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?

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.

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.

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 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.

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.

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.

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 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.

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.

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

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

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.

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.

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.

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.

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).

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.