Evaluation of extraction workflows for quantitative analysis of per- and polyfluoroalkyl substances: A case study using soil adjacent to a landfill

Investigating the partitioning behavior of per- and polyfluoroalkyl substances (PFAS) during thermal landfill leachate evaporation

Thermal landfill leachate evaporator systems can reduce the volume of leachate by up to 97%, while releasing water vapor and producing residuals (volume-reduced leachate and sludge) that are managed on-site. On-site thermal evaporators offer landfill operators leachate management autonomy without being subject to increasingly stringent wastewater treatment plant requirements. However, little is known about the partitioning of PFAS within these systems, nor the extent to which PFAS may be emitted into the environment via vapor. In this study, feed leachate, residual evaporated leachate, sludge, and condensed vapor were sampled at two active full-scale thermal landfill leachate evaporators and from a laboratory-scale leachate evaporation experiment. Samples were analyzed for 91 PFAS via ultra-high pressure liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). Similar trends were observed from Evaporator 1, Evaporator 2, and the laboratory-scale evaporator; ∑PFAS were concentrated in the residual evaporated leachate during evaporation by a factor of 5.3 to 20. All condensed vapors sampled (n = 5) contained PFAS, predominantly 5:3 fluorotelomer carboxylic acid (5:3FTCA), (full-scale vapors 729 - 4087 ng/L PFAS; lab-scale vapor 61.0 ng/L PFAS). For Evaporators 1 and 2, an estimated 9 - 24% and 10%, respectively, of the PFAS mass entering the evaporators in leachate was released with vapor during the days of sample collection. '.

Per- and polyfluoroalkyl substances (PFAS) in construction and demolition debris (CDD): discerning sources and fate during waste management

As regulatory frameworks for per- and polyfluoroalkyl substances (PFAS) evolve, the solid waste community seeks to manage PFAS risks effectively. Despite extensive research on PFAS in municipal solid waste (MSW) and wastewater sludge, there is limited information on a major global waste stream which seldom gleans regulatory oversight - construction and demolition debris (CDD). This study sampled a CDD processing facility to provide material-specific information on the PFAS profile within CDD. The bulk CDD accepted by this facility was separated into major categories, representatively sampled, then characterized for total available PFAS (∑92PFAS). As reprocessed CDD is ultimately recycled or landfilled, often unencapsulated or in unlined landfills, the PFAS leaching potential was also examined using two leaching procedures. Among the categories assessed for total PFAS, carpeting, carpet padding, and gypsum drywall showed elevated concentrations compared to other components, with most of the PFAS mass contributed by precursor species. However, materials with the highest total PFAS, such as carpeting, did not necessarily exhibit the highest leaching, and leachate was predominantly composed of terminal species rather than precursors. Extrapolating these findings with national CDD generation and management data inventories suggests that despite MSW having higher total available PFAS concentrations, the leachability of PFAS from landfilled CDD is comparable, raising legitimate concerns with CDD disposal practices, particularly in unlined CDD landfills.

Assessing the suitability of leachability-based screening levels for per- and polyfluoroalkyl substances (PFAS) risk assessment

In recent years, soil screening levels have been adopted by regulatory agencies for certain per- and polyfluoroalkyl substances (PFAS) to assess the risk of groundwater contamination through leaching. These soil screening levels, determined using an established equilibrium-based partitioning equation, have high variability among regulatory groups largely attributed to the diverse reported partitioning coefficients in the literature. This variability between reported partitioning coefficients, and subsequently soil screening levels, is due to the complex leaching behavior of PFAS not being predicted well by the standard equilibrium-based model. This has led one regulatory group to require batch leaching to assess risk rather than setting default soil screening levels based on partitioning equations. In this work, we conducted leaching experiments on five field-sampled soils impacted by aqueous film-forming foams (AFFF), following Leaching Environmental Assessment Framework (LEAF) Method 1316 and compared the results to expected leaching utilizing an equilibrium-based partitioning equation commonly employed by regulatory agencies to establish soil screening levels. Our analysis found among the six PFAS detected in the soils, which have regulatory leaching thresholds established, the partitioning values assumed by the U.S. EPA exhibited the highest accuracy in predicting leachate concentrations. These partitioning values predicted actual leaching within a ± 20 % margin of error for approximately 50 % of sample points, highlighting limitations in relying solely on equilibrium-based partitioning values as predictors of leaching behavior. This discrepancy between predicted and actual leaching has implications for site managers and regulatory entities overseeing PFAS-contaminated sites, suggesting that soil screening level determinations for PFAS might need to be revised to account for the unique transport characteristics of PFAS.

External liquid calibration method for iodide chemical ionization mass spectrometry enables quantification of gas-phase per- and polyfluoroalkyl substances (PFAS) dynamics in indoor air

Per- and polyfluoroalkyl substances (PFAS) are manufactured chemicals that have been detected across the globe. Fluorotelomer alcohols (FTOHs) are one PFAS class commonly found in indoor air due to emissions from consumer products (e.g., textiles and food packaging) and are human metabolic, atmospheric oxidative, and industrial precursors of perfluoroalkyl carboxylic acids (PFCAs). We developed a quantitative method for real-time analysis of gas-phase FTOHs, perfluoroalkyl acids (PFCAs and GenX), one perfluorooctane sulfonamide (EtFOSA), one fluorotelomer diol (FTdiOH), and one fluorinated ether (E2) using high-resolution time-of-flight chemical ionization mass spectrometry equipped with iodide reagent ion chemistry (I-HR-ToF-CIMS). Herein, we present a direct liquid injection method for external calibration, providing detection limits of 0.19-3.1 pptv for 3 s averaging and 0.02-0.44 pptv for 120 s averaging, with the exception of E2, which had detection limits of 1700 and 220 pptv for 3- and 120 s averaging, respectively. These calibrations enabled real-time gas-phase quantification of 6 : 2 FTOH in room air while microwaving popcorn, with an average peak air concentration of 31.6 ± 4.5 pptv measured 2 meters from a closed microwave. Additionally, 8 : 2 and 10 : 2 FTOH concentrations in indoor air were measured in the presence and absence of a rain jacket, with observed peak concentrations of 110 and 25 pptv, respectively. Our work demonstrates the ability of I-HR-ToF-CIMS to provide real-time air measurements of PFAS relevant to indoor human exposure settings and allow for PFAS source identification. We expect that real-time quantification of other gas-phase PFAS classes is possible, enabling advances in understanding PFAS sources, chemistry, and partitioning.

Contamination of aquatic ecosystems by persistent organic pollutants (POPs) originating from landfills in Canada and the United States: A rapid scoping review

Persistent organic pollutants (POPs) are organic chemical substances that threaten human health and the planet's ecosystems due to their toxicity and their ability to remain intact for a long time, wide distribution throughout the environment, and accumulation and magnification in living organisms through the food chain. Discarded products from landfills and dumpsites are potential sources of POPs due to their persistence for several decades and constant release to surrounding environment. POPs in aquatic systems signal input predominantly from landfills, wastewater treatment plants, sewage, and urban runoff, suggesting a research gap to guide policies to address these unabated releases. This scoping review aims to rapidly identify the key concepts underpinning the containment, translation, and migration of POPs in Canadian and US landfill leachate. The review targeted multidisciplinary perspectives on the topic and spanned forensic biology, environmental sciences, chemistry, and geology. Contaminated municipal solid waste (MSW) landfill characteristics, as reported by government agencies in Canada and the US, were synthesized and harmonized to illustrate the geographical scope of MSW landfills releasing POPs into the surrounding environment. The knowledge and data gaps summarized in this study highlight the need to address the inadvertent release of POPs from Canadian and US landfills, particularly in consideration of dated and degrading landfill infrastructure, the proximity of marginalized people, and the implications of climate change on the countries' more vulnerable landscapes. This review is applicable to the development of future studies that aim to guide environmental protective policies.

Evaluation of per- and polyfluoroalkyl substances (PFAS) in landfill liquids from Pennsylvania, Colorado, and Wisconsin

PER: and polyfluoroalkyl substances (PFAS) have been measured in aqueous components within landfills. To date, the majority of these studies have been conducted in Florida. This current study aimed to evaluate PFAS concentrations in aqueous components (leachate, gas condensate, stormwater, and groundwater) from four landfills located outside of Florida, in Pennsylvania, Colorado, and Wisconsin (2 landfills). The Pennsylvania landfill also provided the opportunity to assess a leachate treatment system. Sample analyses were consistent across studies including the measurements of 26 PFAS and physical-chemical parameters. For the four target landfills, average PFAS concentrations were 6,900, 22,000, 280, and 260 ng L-1 in the leachate, gas condensate, stormwater, and groundwater, respectively. These results were not significantly different than those observed for landfills in Florida except for the significantly higher PFAS concentrations in gas condensate compared to leachate. For on-site treatment at the Pennsylvania landfill, results suggest that the membrane biological bioreactor (MBBR) system performed similarly as aeration-based leachate treatment systems at Florida landfills resulting in no significant decreases in ∑26PFAS. Overall, results suggest a general consistency across US regions in PFAS concentrations within different landfill liquid types, with the few differences observed likely influenced by landfill design and local climate. Results confirm that leachate exposed to open air (e.g., in trenches or in treatment systems) have lower proportions of perfluoroalkyl acid precursors relative to leachate collected in enclosed pipe systems. Results also confirm that landfills without bottom liner systems may have relatively higher PFAS levels in adjacent groundwater and that landfills in wetter climates tend to have higher PFAS concentrations in leachate.

Rapid detection of per- and polyfluoroalkyl substances (PFAS) using paper spray-based mass spectrometry

Traditional PFAS analysis by mass spectrometry (MS) is time-consuming, as laborious sample preparation (e.g., extraction and desalting) is necessary. Herein, we report fast detection of PFAS by paper spray (PS)-based MS techniques, which employs a triangular-shaped filter paper for sample loading and ionization (≤ 3 min per sample). In this study, PS-MS was first used for direct PFAS analysis of drinking water, tap water, and wastewater. Interestingly, food package paper materials can be directly cut and examined with PS-MS for possible PFAS contamination. For samples containing salt matrices which would suppress PFAS ion signal, desalting paper spray mass spectrometry (DPS-MS), was shown to be capable of rapidly desalting, ionizing and detecting PFAS species such as per-fluorooctanoic acid (PFOA) and per-fluorosulphonic acid (PFOS). The retention of PFAS on paper substrate while salts being washed away by water is likely due to hydrophilic interaction between the PFAS polar head (e.g., carboxylic acid, sulfonic acid) with the polar filter paper cellulose surface. The DPS-MS method is highly sensitive (limits of detection:1.2-4.5 ppt) and can be applicable for directly analyzing soil extract and soil samples. These results suggest the high potential of PS-MS and the related DPS-MS technique in real-world environmental analysis of PFAS.

Evaluation of per- and polyfluoroalkyl substances (PFAS) released from two Florida landfills based on mass balance analyses

Per- and polyfluoroalkyl substances (PFAS) have been found at high levels within landfill environments. To assess PFAS distributions, this study aimed to evaluate PFAS mass flux leached from disposed solid waste and within landfill reservoirs by mass balance analyses for two full-scale operational Florida landfills. PFAS mass flux in different aqueous components within landfills were estimated based on PFAS concentrations and water flow rates. For PFAS concentration, 26 PFAS, including 18 perfluoroalkyl acids (PFAAs) and 8 PFAA-precursors, were measured in samples collected from the landfills or estimated based on previous studies. Flow rates of aqueous components (rainfall, evapotranspiration, runoff, stormwater, groundwater, leakage, gas condensate, and leachate) were evaluated through the Hydrologic Evaluation of Landfill Performance model, water balance, and Darcy's Law. Results showed that the average PFAS mass flux leached from the solid waste standardized by area was estimated as 36.8 g/ha-yr, which was approximately 1 % to 3 % of the total amount of PFAS within the solid waste. The majority of PFAS leached from the solid waste (95 % to 97 %) is captured by the leachate collection system, with other aqueous components representing much smaller fractions (stormwater system at 3 % to 5 %, and gas condensate and groundwater at < 1 %). Also, based on the results, we estimate that PFAS releases will likely occur at least over 40 years. Overall, these results can help prioritize components for waste management and PFAS treatment during the anticipated landfill release periods.

The decomposition and emission factors of a wide range of PFAS in diverse, contaminated organic waste fractions undergoing dry pyrolysis

Current treatment options for organic waste contaminated with per- and polyfluoroalkyl substances (PFAS) are generally limited to incineration, composting or landfilling, all resulting in emissions. Dry pyrolysis is a promising emerging alternative to these practices, but there is uncertainty related to the fate of PFAS during this process. The present work first developed a robust method for the determination of PFAS in complex matrices, such as sewage sludge and biochar. Then, a mass balance was established for 56 different PFAS during full-scale pyrolysis (2-10 kg biochar hr^-1, 500-800 °C) of sewage sludges, food waste reject, garden waste and waste timber. PFAS were found in all wastes (56-3651 ng g^-1), but pyrolysis resulted in a ≥ 96.9% removal. Residual PFAS (0.1-3.4 ng g^-1) were detected in biochars obtained at temperatures up to 750 °C and were dominated by long chain PFAS. Emitted PFAS loads ranged from 0.01 to 3.1 mg tonne^-1 of biochar produced and were dominated by short chain PFAS. Emissions made up < 3% of total PFAS-mass in the wastes. Remaining uncertainties are mainly related to the presence of thermal degradation products in flue gas and condensation oils.

Immobilization of per- and polyfluoroalkyl substances (PFAS): Comparison of leaching behavior by three different leaching tests

The evaluation of PFAS immobilization performance in laboratory experiments, especially the long-term stability, is a challenge. To contribute to the development of adequate experimental procedures, the impact of experimental conditions on the leaching behavior was studied. Three experiments on different scales were compared: batch, saturated column, and variably saturated laboratory lysimeter experiments. The Infinite Sink (IS) test - a batch test with repeated sampling - was applied for PFAS for the first time. Soil from an agricultural field amended with paper-fiber biosolids polluted with various perfluoroalkyl acids (PFAAs; 655 μg/kg ∑¹⁸PFAAs) and polyfluorinated precursors (1.4 mg/kg ∑¹⁸precursors) was used as the primary material (N-1). Two types of PFAS immobilization agents were tested: treatment with activated carbon-based additives (soil mixtures: R-1 and R-2), and solidification with cement and bentonite (R-3). In all experiments, a chain-length dependent immobilization efficacy is observed. In R-3, the leaching of short-chain PFAAs was enhanced relative to N-1. In column and lysimeter experiments with R-1 and R-2, delayed breakthrough of short-chain PFAAs (C4) occurred (> 90 days; in column experiments at liquid-to-solid ratio (LS) > 30 L/kg) with similar temporal leaching rates suggesting that leaching in these cases was a kinetically controlled process. Observed differences between column and lysimeter experiments may be attributed to varying saturation conditions. In IS experiments, PFAS desorption from N-1, R-1, and R-2 is higher than in the column experiments (N-1: +44 %; R-1: +280 %; R-2: +162 %), desorption of short-chain PFAS occurred predominantly in the initial phase (< 14 days). Our findings demonstrate that sufficient operating times are essential in percolation experiments, e.g., in column experiments >100 days and LS > 30 L/kg. IS experiments may provide a faster estimate for nonpermanent immobilization. The comparison of experimental data from various experiments is beneficial to evaluate PFAS immobilization and to interpret leaching characteristics.

A systematic review on distribution, sources and sorption of perfluoroalkyl acids (PFAAs) in soil and their plant uptake

Perfluoroalkyl acids (PFAAs) are ubiquitous in environment, which have attracted increasing concerns in recent years. This study collected the data on PFAAs concentrations in 1042 soil samples from 15 countries and comprehensively reviewed the spatial distribution, sources, sorption mechanisms of PFAAs in soil and their plant uptake. PFAAs are widely detected in soils from many countries worldwide and their distribution is related to the emission of the fluorine-containing organic industry. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are found to be the predominant PFAAs in soil. Industrial emission is the main source of PFAAs contributing 49.9% of the total concentrations of PFAAs (Ʃ PFAAs) in soil, followed by activated sludge treated by wastewater treatment plants (WWTPs) (19.9%) and irrigation of effluents from WWTPs, usage of aqueous film-forming foam (AFFFs) and leaching of leachate from landfill (30.2%). The adsorption of PFAAs by soil is mainly influenced by soil pH, ionic strength, soil organic matter and minerals. The concentrations of perfluoroalkyl carboxylic acids (PFCAs) in soil are negatively correlated with the length of carbon chain, log K_ow, and log K_oc. The carbon chain lengths of PFAAs are negatively correlated with the root-soil concentration factors (RCFs) and shoot-soil concentration factors (SCFs). The uptake of PFAAs by plant is influenced by physicochemical properties of PFAAs, plant physiology and soil environment. Further studies should be conducted to make up the inadequacy of existing knowledge on the behavior and fate of PFAAs in soil-plant system.

Underestimation of Per- and Polyfluoroalkyl Substances in Biosolids: Precursor Transformation During Conventional Treatment

Wastewater treatment plants generate a solid waste known as biosolids. The most common management option for biosolids is to beneficially reuse them as an agricultural amendment, but because of the risk of pathogen exposure, many regulatory bodies require pathogen reduction before biosolids reuse. Per- and polyfluoroalkyl substances (PFAS) are well documented in biosolids, but limited information is available on how biosolids treatment processes impact PFAS. Furthermore, quantification of PFAS has focused on perfluoroalkyl acids (PFAAs) which are a small fraction of thousands of PFAS known to exist. The objective of this study was to quantify 92 PFAS in biosolids collected from eight biosolids treatment facilities before and after four pathogen treatment applications: composting, heat treatment, lime treatment, and anaerobic digestion. Overall, total PFAS concentrations before and after treatment were dominated by PFAA precursor species, in particular, diPAPs which accounted for a majority of the mass of the Σ92PFAS. This differs from historic data that found PFAAs, primarily PFOS, to dominate total PFAS concentrations. Treatment options such as heat treatment and composting changed the ratio of PFAA precursors to PFAAs indicating a transformation of PFAS during treatment. This study finds that PFAA precursors are likely underrepresented by other studies and make up a larger percentage of the total PFAS concentration in biosolids than previously estimated.

Concentrations of perfluoroalkyl and polyfluoroalkyl substances before and after full-scale landfill leachate treatment

Many consumer and industrial products, industrial wastes and dewatered sludge from municipal wastewater treatment plants containing per- and polyfluoroalkyl substances (PFAS) are disposed of in landfills at the end of their usage, with PFAS in these products leached into landfill leachates. On-site leachate treatment is one possible method to reduce PFAS in leachates. Many landfills are equipped with on-site leachate treatment systems, but few full-scale facilities have been systematically evaluated for PFAS concentration changes. The objective of this study was to evaluate a cross-section of full-scale on-site landfill treatment systems to measure changes in PFAS concentrations. Leachate samples were collected before and after treatment from 15 facilities and were evaluated for 26 PFAS, including 11 perfluoroalkyl carboxylic acids (PFCAs), 7 perfluoroalkyl sulfonic acids (PFSAs), and 8 perfluoroalkyl acid precursors (PFAA-precursors). Transformation of precursors was evaluated by the total oxidizable precursor (TOP) assay. Results showed no obvious reductions in total measured PFAS (∑26PFAS) for on-site treatment systems including ponds, aeration tanks, powdered activated carbon (PAC), and sand filtration. Among evaluated on-site treatment systems, only systems fitted with reverse osmosis (RO) showed significant reductions (98-99 %) of ∑26PFAS in the permeate. Results from the TOP assay showed that untargeted PFAA-precursors converted into targeted short-chain PFCAs increasing ∑26PFAS in oxidized samples by 30 %, on average. Overall, results of this study confirm the efficacy of RO systems and suggest the presence of additional precursors beyond those measured in this study.

An Integrated Approach for Determination of Total Per- and Polyfluoroalkyl Substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are difficult to analyze in environmental media due challenges such as extraction recovery and lack of analytical standards. The total oxidizable precursor (TOP) assay and suspect screening analysis coupled with semiquantitative (SQ) concentration estimates are two approaches to assess total PFAS in environmental media, but studies are needed to optimize workstreams for total PFAS analysis. This study applied two soil extraction methods, TOP assay, and SQ analysis to three aqueous film-forming foams (AFFFs) and three AFFF-impacted soils. In soils, the total PFAS estimated with results from an extraction method utilizing sequential acidic and basic solvents led to a 35% increase in precursors during TOP assay relative to results from a basic solvent only extraction in one of three soils tested, but concentrations did not increase significantly in remaining soils. Furthermore, sample-specific dilution schemes were required to overcome matrix effects caused by the acidic extraction step that influenced estimates of total PFAS by SQ analysis. The results highlight that there is not an advantage to routine application of an acid extraction step in PFAS-impacted soils. In three AFFFs, suspect screening of post-TOP samples identified eight classes of PFAS present after oxidation. Concentrations of three classes increased, suggesting they are new TOP end points. Concentrations of the remaining five classes either remained constant after TOP or exhibited slight decreases. As a result, combined TOP and SQ workstreams may yield the most representative assessment of total PFAS composition and concentration. The eight classes of PFAS present after TOP did not degrade in harsh conditions. Some are structurally similar to PFCAs and PFSAs and are known to occur in the environment, suggesting a similar degree of persistence and a need for more routine monitoring.

Background per- and polyfluoroalkyl substances (PFAS) in laboratory fish diet: Implications for zebrafish toxicological studies

Current attention is focused on determining the potential for per- and polyfluoroalkyl substances (PFAS) to adversely impact human health. Zebrafish are a popular biological model because they share early development pathways with humans. A dietary exposure paradigm is growing in popularity in the zebrafish model because the outcomes often translate to humans. To create a diet of known composition, it is crucial to understand background PFAS levels present in zebrafish diet. Background PFAS, if present, potentially confounds interpretation of toxicological data. To date, no studies document the PFAS background levels in laboratory fish diet and there is only limited information on some pet foods. The objective of this study was to develop and validate an analytical method for up to 50 target PFAS in high lipid and protein content laboratory fish diets and pet foods. Long-chain perfluoroalkyl carboxylic acids (C9-C13) and perfluorooctane sulfonate (PFOS) were quantified in 11 out of 16 laboratory fish diets and in three out of five pet fish foods. Foods for pet birds, lizards, and dogs were below the limit of detection for all PFAS. In two of the laboratory fish diets, PFOS concentrations were >1.3 ng/g and the total PFAS for the three laboratory fish diets exceeded 1.0 ng/g. Hundreds of biomedical laboratories across the world utilize these commercial laboratory fish diets, and these results indicate that numerous zebrafish colonies may be inadvertently receiving significant dietary PFAS exposures. In light of this new information, it is critical to design PFAS studies with appropriate controls with measured background PFAS concentrations in the diet and to urge caution when interpreting the results.

Survey of per- and polyfluoroalkyl substances (PFAS) in surface water collected in Pensacola, FL

As the persistence of per- and polyfluoroalkyl substances (PFAS) become a global concern, information about the occurrence and characteristics of PFAS in estuarine and marine ecosystems is poorly represented. In this study, the presence of 51 PFAS were monitored in the Pensacola Bay System (PBS), Florida, USA. Due to the presence of many potential PFAS sources in close proximity to the PBS (e.g., military bases, industries, airports and several firefighting stations), the distribution and concentration of PFAS in this estuarine environment provides insights into the fate of these complex compounds as well as the possible impacts on coastal systems. Surface water was collected and analyzed from 45 different sites via Strata-X-AW cartridge extractions and ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Recoveries for many PFAS (13/51) were >60% (mean 77 %), with relative standard deviations below 20%, except for N-methylperfluoro-1-octanesulfonamidoacetic acid (N-MeFOSAA) (22%). Of the perfluoroalkyl carboxylic acids (PFCAs), which comprised the majority of PFAS detected: perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were present in all samples; however, perfluoropentanoic acid (PFPeA) was the individual PFAS with the highest concentration of this group (51.9 ng.L⁻¹, at site 81). The PFAS detected at the highest concentrations were perfluoroalkyl sulfonic acids (PFSA), with perfluorooctane sulfonic acid (PFOS) having the highest detected concentration (269 ng.L⁻¹, at site 81). At all sites, at least eight or more PFAS were quantified. Past and current use of PFAS-containing materials and their fate in areas surrounding military bases, airports, and industries, require more in-depth monitoring efforts to better determine the need for regulation, management, and/or remediation. Here, sites located close to areas suspected of PFAS use had elevated concentrations. For example, one coastal location near an airfield had a ΣPFAS of 677 ng.L⁻¹. Expansion from these ongoing efforts will focus on assessment of PFAS-related effects in local wildlife and evaluating the distribution of PFAS at these “hotspot” sites during large episodic weather events, a critically understudied phenomenon regarding PFAS and vulnerable coastal environments.

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Elevated PFAS levels were quantified in Pensacola Bay surface water.

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ΣPFOS was the compound detected with the highest concentration between all PFAS.

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PFAS diversity increased near sites with industrial effluent and suspected AFFF usage.

Per- and Polyfluoroalkyl Substances (PFAS) in Street Sweepings

One hundred and seventeen street sweeping samples were collected and analyzed for per- and polyfluoroalkyl substances (PFAS). Fifty-six samples were collected in one city (Gainesville, Florida) allowing for an in-depth city-wide characterization. Street sweepings from five other urban areas, (Orlando, n = 15; Key West, n = 15; Pensacola, n = 12; Tampa, n = 13; and Daytona Beach, n = 6) were analyzed to provide a city-to-city comparison of PFAS. Within our analytical workflow, 37 PFAS were quantified across all samples, while the maximum number of PFAS quantified at one site was 26. Of those PFAS quantified in Gainesville, 60% were perfluoroalkyl acids (PFAAs) and 33% were precursors to PFAA. Among the PFAAs, short-chain perfluoroalkyl carboxylic acids (PFCAs) were the dominant class representing 26% of the total PFAS by concentration. In the comparison across different urban cities, the dominant compound by concentration and frequency of detection varied; however, perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonic acid (PFOS_lin) were the two PFAS that were detected the most frequently. This study documents the first-time detection of hexadecafluorosebacic acid and perfluoro-3,6,9-trioxaundecane-1,11-dioic acid within environmental samples.

Method for extraction and analysis of per- and poly-fluoroalkyl substances in contaminated asphalt

The legacy use of aqueous film-forming foam (AFFF) has led to the generation of large volumes of per- and poly-fluoroalkyl substances (PFAS)-contaminated asphalt materials, especially at airports and fire training areas. The management of such PFAS-contaminated asphalt materials requires an understanding of PFAS concentrations in these materials. This study, therefore, aimed to develop a suitable extraction methodology for the analysis of 22 target PFAS (i.e., carboxylic acids, sulfonic acids and fluorotelomers) in asphalt materials. A series of experiments was conducted to optimise extraction solvent composition, as well as to assess the performance of the chosen method under various conditions (i.e., sonication temperature, PFAS contamination level, asphalt core composition and timing of stable isotope addition used as internal standard). The methanol-based extractants performed best due to their accuracy and precision, which were within the acceptable range (extraction efficiency between 70 and 130% and RSD < 20%). The method which involved three successive extractions with methanol/1% NH₃ by ultrasonication at 25 °C was selected due to its performance and ease of operation. The mean recovery of a vast majority of PFAS was found to be in the acceptable range. Tests on the timing of addition of stable isotope (SI)-labelled PFAS internal standards indicate that the recoveries obtained, regardless of when the stable isotopes were added, were within the acceptable range for PFAS. The accuracy and precision of PFAS recoveries were not affected by PFAS spike level (2 μg kg^-1 and 200 μg kg^-1), as well as sample composition (based on the location of asphalt material in the field). Low RSDs were achieved for asphalt cores collected from a contaminated site covering a wide range of concentrations (from LOQ to 2135 mg kg^-1), demonstrating the suitability of the sample preparation method for real-world samples. The results from the interlaboratory testing were also in good agreement and validated the proposed PFAS extraction and analytical approach.

Extraction and Matrix Cleanup Method for Analyzing Novel Per- and Polyfluoroalkyl Ether Acids and Other Per- and Polyfluoroalkyl Substances in Fruits and Vegetables

Per- and polyfluoroalkyl ether acids (PFEAs) are a subclass of per- and polyfluoroalkyl substances (PFAS) that are detected with increasing frequency in environmental matrices. Diet can be an important route of PFEA exposure, but the presence of PFEAs in food is poorly understood. Extraction methods for food samples exist for traditionally studied PFAS, but their suitability for PFEAs and other novel PFAS remains unknown. In this study, an extraction and matrix cleanup method was developed to quantify 45 PFAS, including 13 PFEAs, 3 perfluoroalkane sulfonamides, and 6 fluorotelomer carboxylic acids in 10 types of fruits and vegetables. Homogenized samples were extracted with basic methanol, and resulting extracts were diluted with water and cleaned up using solid-phase extraction with weak anion-exchange cartridges. The method was validated by performing spike-recovery experiments at spike levels of 1 ng/g in all 10 matrices and 0.1 ng/g in 2 matrices. For PFAS without a corresponding isotopically labeled internal standard (IS), adopting an IS with a similar chromatographic retention time generated the most accurate recoveries. Dependent upon the matrix, recoveries of 38-44 PFAS (including 10-13 PFEAs) fell within 50-150% for samples spiked at 1 ng/g. Recoveries of 40 and 38 PFAS in blueberries and corn, respectively, fell within 50-150% for samples spiked at 0.1 ng/g. Method quantification limits (MQLs) of PFAS in pure solvents were determined as the lowest calibration level with an accuracy between 70 and 130%. To compensate for matrix effects, a matrix factor was applied on the basis of the analyte response in different matrices relative to the pure solvent. The MQLs of 45 PFAS (including 13 PFEAs) in 10 matrices ranged from 0.025 to 0.25 ng/g. Overall, this method is capable of sensitively quantifying 45 PFAS in many fruits and vegetables.

Recent advances in mass spectrometry analytical techniques for per- and polyfluoroalkyl substances (PFAS)

The ubiquitous presence of per- and polyfluoroalkyl substances (PFAS) in various environments has led to increasing concern, and these chemicals have been confirmed as global contaminants. Following the chemical regulatory restrictions imposed, PFAS alternatives that are presumed to be less toxic have been manufactured to replace the traditional ones in the market. However, owing to the original release and alternative usage, continuous accumulation of PFAS has been reported in environmental and human samples, with uncertain consequences for ecosystem and human health. It is crucial to promote and improve existing analytical techniques to facilitate the detection of trace amounts of PFAS in diverse environmental matrices. This review summarizes analytical methods that have been applied to and advanced for targeted detection and suspect screening of PFAS, which mainly include (i) sampling and sample preparation methods for various environment matrices and organisms, and quality assurance/quality control during the analysis process, and (ii) quantitative methods for targeted analysis and automated suspect screening strategies for non-targeted PFAS analysis, together with their applications, advantages, shortcomings, and need for new method development.

Per- and polyfluoroalkyl substances (PFAS) in sediments collected from the Pensacola Bay System watershed

Sediment samples from 25 locations in the Pensacola Bay System (PBS) watershed were analyzed for the presence of 51 per- and polyfluoroalkyl substances (PFAS) using ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) and selected reaction monitoring. Results revealed quantifiable concentrations of PFAS in all sampling locations. More specifically, perfluorobutanoic acid (PFBA) was present in every sediment sample with a minimum and maximum concentration of 0.04 to 0.48 ng g-1 dry weight, respectively, across the 25 sites with an average of 0.1 ± 0.09 ng g-1. While PFOS, with an average of 0.11 ± 0.14 ng g-1 (range: Collapse

Key Words

• Pensacola Bay System
• Per-and polyfluoroalkyl substances (PFAS)
• Sediment
• Storm events
• UHPLC-MS/MS

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MESH Headings Collapse

Grants

• EPA999999 Intramural EPA

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Affiliation(s)

Atiye Ahmadireskety Chemistry Department, University of Florida, Gainesville, Florida, USA
Bianca F. Da Silva College of Veterinary Medicine, Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA
Jill A. Awkerman Gulf Ecosystem Measurement & Modeling Division, US Environmental Protection Agency, Gulf Breeze, Florida, USA
Joe Aufmuth George A. Smathers Libraries, University of Florida, Gainesville, Florida, USA
Richard A. Yost Chemistry Department, University of Florida, Gainesville, Florida, USA
John A. Bowden Chemistry Department, University of Florida, Gainesville, Florida, USA College of Veterinary Medicine, Department of Physiological Sciences, University of Florida, Gainesville, Florida, USA

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Effects of hydrothermal treatments on destruction of per- and polyfluoroalkyl substances in sewage sludge

Sewage sludge has become a sink of per- and polyfluoroalkyl substances (PFAS) due to the ineffectiveness of PFAS removal during conventional activated sludge treatment process. In this study, we evaluated the performance of an enhanced method for PFAS extraction from sewage sludge. Significant matrix effect was observed for samples derived from untreated and hydrothermally treated sludge. Extra steps for removing potential interferences were thus needed to reduce these matrix effects and improve the accuracy of PFAS quantification. Hydrothermal treatment at 165 °C for 0.5/2 h and 250 °C for 0.5 h increased the concentration of extractable PFAAs in treated sludge. Increasing the temperature to 300 °C resulted in complete degradation of PFCAs after hydrothermal processing, but still increased the concentrations of PFSAs and PFAA precursors. The concentration increase could be due to the conversion of PFAA precursors to PFAAs and the release of PFAAs from sewage sludge during thermal treatment. Ca(OH)₂ addition to hydrothermal treatment completely removed PFAA precursors but significantly increased the extractable PFAAs, except PFHpA and PFHxS, at 165 °C and all PFSAs at 300 °C. This study revealed the difficulties in extracting and quantifying PFAS in sludge and demonstrated the need for further research on finding suitable solutions for complete removal or destruction of PFAS in highly heterogeneous sewage sludge.