Per- and polyfluoroalkyl substances (PFAS) are environmentally persistent contaminants with the potential to adversely affect ecosystem health. Characterizing the spatial dynamics, bioavailability, and potential for biomagnification within exposed ecosystems is necessary for gauging potential risk to wildlife and humans. In this study, we analyzed PFAS concentrations in surface waters, sediments, and biota collected from 30 locations across watersheds on the U.S. Department of Energy's Savannah River Site (SRS). The 800 km2 SRS was designated the nation's first National Environmental Research Park in 1972, and we contextualize measured PFAS concentrations within a rich history of environmental and ecotoxicological research. Concentrations of total PFAS ranged from nondetect to 2,226 ng/L in water, 65 ng/g in sediment, and 158 ng/g in mosquitofish. Per- and polyfluoroalkyl substance concentrations in fish were elevated despite relatively low concentrations in water and sediment at some locations, demonstrating the importance of including biota for bioavailability assessments. Co-occurrence analyses of PFAS with 22 metals/metalloids revealed strong positive correlations between PFAS and metal concentrations in sediment. At the landscape scale, we identify linkages between PFAS concentrations and watershed landcover dynamics, including watershed size, proportion of watershed development, and sediment composition. Additionally, we examine PFAS concentrations and stable isotope signatures in an affected stream community and find that sum PFAS, long-chain perfluoroalkyl carboxylic acid (C8 up to C14), perfluorooctane sulfonic acid, and 7:3 fluorotelomer carboxylic acid concentrations were positively related to nitrogen isotope signatures, indicating their potential biomagnification. Collectively, our study characterizes initial environmental and biological PFAS levels on the SRS within stream ecosystems and will serve as a guide for future ecotoxicological studies and risk assessments.

Portland Cement Concrete (PCC) pavement is a highly recycled material globally. Recently, it has been discovered that some PCC pavement at military installations, firefighting training sites, and aviation facilities was vulnerable to per- and polyfluoroalkyl substances (PFAS) exposure via use of aqueous film forming foams (AFFF). However, little is known about the distribution of PFAS within intact PCC pavements, nor the implications of recycling AFFF-impacted PCC pavements. In this study, approximately 4,500kg of PFAS-impacted concrete slabs collected from a former defense installation (in the United States) were processed in a full-scale recycling operation. Surface powder samples (< 0.25cm depth) and pavement cores were collected from select slabs to screen surficial PFAS concentrations and characterize PFAS as a function of pavement depth. Additional clean PCC was processed, after the impacted load, to monitor potential PFAS transfer to subsequent material prepared by the same recycling equipment. Samples were analyzed for 40 PFAS via ultra-high pressure liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). Weighted averages from PCC depth profile analysis were more effective in estimating the boundaries (1,300 – 4,300µg/kg) of expected sum of PFAS concentrations (ΣPFAS) in the homogenized final product (HFP) of crushed concrete (average 2,320µg/kg) than surface screening concentrations alone (504 – 60,400µg/kg). PFAS transfer to clean concrete crushed immediately following the PFAS-laden load was minimal, where the ƩPFAS decreased from 27µg/kg to 9µg/kg within 4,500kg of clean PCC processed, and to below limits of quantification within 5,400kg of clean PCC processed.

Per- and polyfluoroalkyl substances (PFAS) are widespread, highly persistent and mobile contaminants that accumulate and biomagnify in marine food webs. Although PFAS have been reported in several marine predators, data from long-lived Arctic species remain scarce. Here, we explored PFAS profiles in Greenland sharks (Somniosus microcephalus), from Svalbard, Norway, to evaluate their occurrence in one of the longest-lived vertebrates; many, if not all the sampled individuals in this study are likely to have been born before PFAS introduction. Plasma analysis from sharks (n = 43) revealed a range of long-chain PFAS, dominated by linear-perfluorooctane sulfonate (L-PFOS) and long-chain perfluoroalkyl carboxylic acids (PFCAs; C9-C14). The total concentration of detected PFAS (∑PFAS) ranged from 0.61 to 10.73 ng/g, with a median of 3.27 ng/g plasma. However, females (n = 27) contained higher concentrations of ∑PFAS, with median and range (4.13; 0.79-10.73 ng/g) values higher than males (n = 16) with ∑PFAS (2.33; 0.61-8.58 ng/g) (p < 0.05). Spearman correlation run on biological parameters showed that PFAS concentrations were positively correlated with girth and body mass but showed no association with the body length of these sharks. When compared to plasma PFAS in other marine predators from Svalbard, Greenland sharks showed lower levels except in select benthic-feeding pinnipeds, which had the lowest levels of PFAS particularly PFCAs (C10-C14). However, Greenland sharks are among the highest levels of ∑PFAS across the global cohort of shark plasma studied to date. Our findings highlight that sharks that live in cold and deep waters of the Arctic are exposed to PFAS, emphasizing the need for continued monitoring of emerging contaminants in remote environments and long-living predators.

The invasive Burmese python (Python bivittatus) is an optimal sentinel to monitor the presence and impact of chemicals of emerging concern in the Florida Everglades, a designated World Heritage Site. As a relatively long-lived apex predator, that is both a generalist and a holophagous consumer of prey, python tissue burdens can highlight the bioaccumulative potential of pollutants, reflecting what is present in the ecosystem. Further, as these invasive snakes are targeted for removal by the state, opportunistic sampling of this semi-aquatic apex predator reduces the need for handling of vulnerable native species. In this study, livers from 67 pythons, collected within or near the Greater Everglades Ecosystem, were monitored for 30 per- and polyfluoroalkyl substances (PFAS) using high-performance liquid chromatography-tandem mass spectrometry. Across all python livers, linear perfluorooctanesulfonic acid was the most prominent PFAS by both frequency (93%) and concentration (median 89 ng/g dw). While no statistical difference was determined in PFAS concentrations in livers collected from pythons sampled from eastern and western sampling locations (surrounding the Everglades), a sex-based difference was observed. Overall, males had a statistically higher ∑PFAS concentration (p < 0.0001) when compared to females. Further, females tended to have lower ∑PFAS concentrations as they become longer and heavier, suggesting potential maternal transfer. The median ∑PFAS concentration was 111 ng/g dw, which exceeded that observed in livers collected from native apex predators, American alligators (Alligator mississippiensis). As demonstrated herein, pythons represent an optimal sentinel for assessing the overall PFAS burden within the greater Everglades ecosystem.

Per- and polyfluoroalkyl substances (PFAS) are an emerging contaminant globally, with recent attention regarding their presence in South Africa; however, to date, most studies have focused on their presence and impact on aquatic systems. Few sentinels exist capable of defining the presence and role of PFAS in urban environments. Here, we have demonstrated the use of an opportunistic sampling strategy (e.g., roadkill), as a means to obtain specimens capable of defining the potential urban burden of PFAS. Within many urban environments in South Africa, snakes have become widespread, due to the abundance of food and shelter. Employing the roadkill sampling strategy, the livers of three species of apex venomous snakes, black mamba (BM, Dendroaspis polylepis, n = 28), eastern green mamba (Dendroaspis angusticeps, n = 5), and Mozambique spitting cobra (Naja mossambica, n = 6), were sampled. The snakes were then monitored for 30 PFAS in and around the urban center of Durban, South Africa, using liquid chromatography-tandem mass spectrometry. Overall, nine PFAS were quantified across the snakes sampled, dominated by long chain species, along with the presence of an emerging class of replacement PFAS, 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (6:2 Cl-PFESA). This study reports some of the highest ∑PFAS documented in South African biota at 1084 ng/g dry weight (dw; median ∑PFAS of 511 ng/g dw for BM). While there are obvious caveats to utilizing roadkill for PFAS monitoring, these opportunistic throw-away samples could become useful for tracking the fate of PFAS in threatened or dangerous species, especially within urban environments. Further, these urban sentinels can provide data for a current research gap (terrestrial fate and transport) and offer a glimpse into potential human exposure risks in regions where urban pollution is a growing concern.

Fly ash formed during municipal solid waste incineration (MSWI) contains constituents of concern including per- and polyfluoroalkyl substances (PFAS) and trace metals. However, PFAS occurrence in distinct fly ash fractions and the relationship between PFAS and metals in such systems is not well understood. This study investigated the occurrence and distribution of PFAS and trace metals (As, Ba, Cd, Cr, Pb, Sb, Se) in distinct MSWI fly ash fractions and the influence of physical-chemical characteristics (i.e. pH, particle size distribution, loss-on-ignition). In characterizing two, full-scale MSW combustors and their generated fly ashes, we demonstrated that PFAS and volatile metals (As, Cd, Pb, Sb) exhibit similar distributions, with concentrations in distinct FA fractions ranging from 0.007 - 0.830 ng/g and 1,080 - 3,640 mg/kg, respectively. PFAS and volatile metals concentrations exhibited positive correlations with loss-on-ignition and negative correlations with particle size, suggesting combustion efficiency, organic carbon content, and surface area to be primary drivers. A positive correlation exists between PFAS and volatile metals concentrations (rs > 0.7), suggesting they could be managed in concert. The highest constituent concentrations were observed in fly ash captured within the baghouse of both combustors, pointing to an opportunity for optimized management of fly ash through targeted segregation of baghouse residuals. This data provides the first comprehensive assessment of PFAS and metals in distinct FA fractions from US MSWIs and identified the drivers for PFAS and trace metals partitioning to inform safe and optimal management.

The historical release of aqueous film forming foams (AFFF) has contaminated surrounding concrete and asphalt pavements with per- and polyfluoroalkyl substances (PFAS). Recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP) are heavily recycled; one recycling route being bound recycling where RCA and RAP are incorporated into new pavements. As a proof-of-concept, sources of clean RCA and RAP were exposed to a legacy AFFF formulation in the laboratory and then recycled into new concrete and asphalt, respectively. Additionally, RCA exposed to AFFF at a defense site was incorporated into new concrete in the same manner. Intact and crushed specimens of the reformed pavements that contained AFFF-impacted recycled aggregates underwent leach testing. Samples were analyzed for 40 PFAS using ultra high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Leaching of intact specimens demonstrated ≥ 95% encapsulation of ∑40PFAS in both concrete and asphalt, where concrete incorporating field-collected RCA immobilized ∑40PFAS to the greatest extent (99% encapsulation). The degree of ∑40PFAS encapsulation was lower when reformed specimens were crushed and leached (44 – 60% encapsulation). The findings suggest that PFAS can be encapsulated during bound pavement recycling, but the greatest leaching risk is associated with the reformed pavement’s end-of-life when it is crushed/milled.

Since traditional management of landfill leachate at wastewater treatment plants was found to release per- and polyfluoroalkyl substances (PFAS), alternative technologies are being evaluated for PFAS treatment efficiency. Thermal evaporation is an emerging landfill leachate treatment option allowing for autonomous, onsite management of concentrated residuals while discharging the treated bulk as vapor. This study evaluated the potential of thermal evaporation for onsite PFAS retention by comparing PFAS concentrations in the inputs (leachate and landfill gas) and outputs (evaporation residuals and vapor) of a full-scale evaporator and explored PFAS deposition onto nearby soil. Liquid chromatography-tandem mass spectrometry analyzing 66 anionic PFAS (iPFAS) and gas chromatography-high resolution mass spectrometry analyzing 27 neutral PFAS (nPFAS) were employed. Both iPFAS and nPFAS were measured in vapor emissions (126 and 783 ng/m3, respectively). The percent removal of iPFAS from re-condensed vapor was > 92 % for six perfluoroalkyl acids, but only 32 % for 5:3 fluorotelomer carboxylic acid, the dominant iPFAS in vapor. However, the percent retention in evaporation residuals was only 48-82 % for the same perfluoroalkyl acids, and an added resin sampler captured additional gas-phase iPFAS emissions previously overlooked. iPFAS and nPFAS present in landfill gas (106 and 621,000 ng/m3, respectively) may also contribute to PFAS emissions due to incomplete combustion. Concentrations of iPFAS in soil within 100 m of the evaporator (0.174-4.87 ng/g) were higher (p-value < 0.01) than those in soil 1-4 km away (0.016-0.393 ng/g). These results demonstrate the need for further optimization of thermal evaporation systems to prevent airborne PFAS emissions.

Per- and polyfluoroalkyl substances (PFAS) are a resilient class of anthropogenic contaminants of emerging concern with over 12 000 individual compounds that have been noted for industrial applications, consumer goods, and food packaging materials. In general, the most common contributors to PFAS environmental pollution are aviation facilities, specifically those that use aqueous film forming foams (e.g., at military bases and airports). In this study, we examined the presence of PFAS across Okinawa Island (Japan) due to its large-scale U.S. military presence throughout the island. Surface water was collected at 61 sites across the island to achieve maximum geographical coverage of the island while also collecting near suspected PFAS sources; 31 PFAS were monitored using a 12 min HPLC-MS/MS method. A total of 15 PFAS were detected and quantified around the island with a mean Σ15PFAS of 16.3 ng L-1 and a maximum site concentration of 164.3 ng L-1. Region-specific PFAS profiles were observed across the island, including the overwhelming presence of PFHpA in the northern region of the island, revealing the possibility of multiple PFAS source points in Okinawa. The resultant data herein provides the first island-wide examination of PFAS "hotspots" across Okinawa and is a critical first step toward increasing PFAS awareness and action.

With thousands of documented perfluoroalkyl and polyfluoroalkyl substances (PFAS), novel methods are needed to comprehensively characterize these fluorinated compounds in the environment, biota, and humans. Despite being the most common approach, liquid chromatography high-resolution mass spectrometry (LC-HRMS) only covers a fraction of PFAS. To address this gap, we developed a nontargeted gas chromatography high-resolution mass spectrometry (GC-HRMS) workflow to extend coverage of the PFAS chemical space, developing and incorporating the most extensive GC HRMS PFAS libraries to date covering over 1,900 electron ionization (EI) and positive chemical ionization (PCI) predicted and experimental spectra. Five environmental and biological matrices were assessed: aqueous film forming foam (AFFF), industrial outfall, municipal leachate, residential floor dust, and human blood. A novel compound was identified (2-(perfluorohexyl)ethanethiol) in multiple AFFF formulations. A rarely monitored PFAS was additionally detected (N-methyl-N-(2-hydroxyethyl)perfluorooctanesulfonamide, N-MeFOSE) in human blood, industrial outfall, municipal leachate, and residential floor dust at high frequency and abundance. A comparison to LC-HRMS approaches for leachate and blood showed no overlap between annotated PFAS. The nontargeted workflow presented here provides essential tools to expand PFAS monitoring capabilities and identify previously undetected compounds that may pose significant health and environmental risks.

Per- and polyfluoroalkyl substances (PFAS) have garnered increasing attention in recent years and non-targeted analysis (NTA) has become essential for elucidating novel PFAS structures. NTA and PFAS research have been dominated by liquid chromatography - mass spectrometry (LC-MS) with gas chromatography - mass spectrometry (GC-MS) used less often as evidenced by bibliometrics. However, the performance of GC-MS in NTA studies (GC-NTA) rivals that of LC-ESI-MS and GC-MS is shown to cover a complimentary chemical space. An LC-ESI-MS amenability model applied to a list of approximately 12,000 PFAS revealed that less than 10% of known PFAS chemistry is predicted to be amenable to typical LC-MS analysis. Therefore, there is strong potential for applying GC-MS methods to more fully assess the PFAS environmental contamination landscape, uniquely shedding light on both known and novel PFAS, especially within the chemical space realm of volatile and semi-volatile PFAS. Waste streams from fluorochemical manufacturing facilities have been heavily studied using LC-MS and targeted GC-MS; however, GC-NTA is needed to discover novel PFAS that are not amenable to LC-MS emitted from facilities. Studies on the incineration of PFAS-containing materials, such as aqueous film forming foam, have focused on the destruction of parent compounds and little is known about the transformation products formed during such processes. GC-NTA holds the potential to elucidate transformation products formed when PFAS are incinerated. Wastewater treatment plants and landfills are known sources of PFAS to the environment, yet GC-NTA is needed to understand air emissions of PFAS and PFAS transformation products from these sources. Consumer products are known to lead to indoor exposures to PFAS via emissions to air and dust but research in this area has either used LC-MS or targeted GC-MS. Despite the challenges with advancing GC-NTA, we call on NTA researchers, grantors, managers, and other stakeholders to recognize the potential and necessity of GC-NTA in PFAS research so that we may face these challenges together.

Over the past several decades, coral reefs have faced a multitude of environmental stressors, resulting in major bleaching events all over the globe. Chemical stressors remain highly understudied in regards to their impact on the health of reef-building corals. Per- and polyfluoroalkyl substances (PFAS) are an expanding class of industrial chemicals that have high persistence in the environment, with many suspected adverse health impacts in vertebrate and invertebrate species. Unfortunately, there are little ecotoxicological data demonstrating possible impacts of PFAS on scleractinian corals with symbiotic algae, and there is no relevant literature that investigates their impact on coral larvae. Coral larvae are at high risk for PFAS exposure as they spend a prolonged period of dispersal drifting through the surface water prior to metamorphosis/settlement. The purpose of this study was to assess the impact of acute perfluorooctanesulfonic acid (PFOS) exposure on symbiotic and aposymbiotic Acropora aff. tenuis larvae to better understand possible ecosystem level impacts of PFAS exposure on coral reefs. Impacts to symbiont acquisition, metamorphosis, and lipidome of the larvae were investigated. Exposure to as low as 1 mg/L PFOS for 24-h decreased symbiont uptake in A. aff. tenuis larvae (p < 0.05). Further research is necessary to understand possible impacts of PFOS on metamorphosis of coral larvae. Additionally, significant alterations to the lipidome were detected following exposure to approximately 1.0 mg/L and approximately 6.7 mg/L PFOS in symbiotic A. aff. tenuis larvae, though no impact was detected in aposymbiotic A. tenuis larvae. Future research is needed to understand the impact of PFAS on the symbiotic relationship between the algae and corals as well PFAS impacts on free living Symbiodiniaceae.

Per- and polyfluoroalkyl substances (PFAS) have been detected in wildlife globally, yet limited research exists on their presence in terrestrial vertebrate hibernators, such as the American black bear (Ursus americanus). Our goal was to determine plasma PFAS fluctuations across physiological stages (hyperphagia, hypophagia, mid-hibernation, late-hibernation, and post-hibernation) and temporal trends in PFAS levels in black bears over a period of three decades. Plasma from individual black bears (n = 99) contained a range of perfluoroalkyl sulfonic acids (PFSAs; C6-8) and long-chain perfluoroalkyl carboxylic acids (PFCAs; C8-14). Total PFAS concentrations (∑₁₀PFAS) ranged from 6.55 to 113 ng/g plasma in all black bears combined. Linear mixed-effects models revealed significant increases in ∑PFSAs from hyperphagia to late-hibernation in female black bears, whereas ∑PFCAs remained stable or declined. Notably, both PFAS classes exhibited a marked decrease during post-hibernation arousal, highlighting the influence of distinct physiological stages on PFAS levels in plasma. ∑PFSA temporal trends between 1989 and 2015 peaked around year 2002 and steadily decreased, likely due to regulatory phase-outs of C8-based compounds. In contrast, several long-chain PFCAs showed increasing trends, suggesting continued environmental inputs potentially linked to ongoing production or degradation of PFCA precursors.

Systemic lupus erythematosus (SLE, lupus) is a chronic autoimmune disease which has a complex etiology and suffers from both high false positive rates and false negative rates in diagnosis and classification. Substantial lipid changes have been observed previously in lupus patients, hence we carried out the most comprehensive lipidomics study in lupus to date using LipidMatch Flow. In this study, we investigated various sub-categories of lupus including lupus nephritis, active versus non-active lupus, as well as comparisons to non-lupus controls. A total of 1105 unique lipids spanning 36 lipid classes (or sub-classes) were annotated in blood plasma samples; of these, 111 lipids changed significantly between controls and active lupus. We determined for the first time, specific oxidized lipid markers, with oxidized triacylglycerols being the most significantly increased lipid subclass in active lupus as compared to controls. Other indicators of oxidative stress included decreased lipids containing ether linkages and/or polyunsaturated fatty acids. Increased Cer(d18:1/16:0) and decreased C20-22 containing species (especially C20:4) indicated an inflammatory response in patients with active lupus. Furthermore, we determined a significant decrease of glycerophosphoserines, which are known inflammation suppressors, in patients with lupus and a decrease in Coenzyme Q9 and Q10; supplementation of lupus patients with Coenzyme Q10 has been shown to be protective [1-4]. Several unique lipids with unknown biology are also shown to significantly changed in active lupus. Many of these trends were also observed in non-active lupus, suggesting lipidomics related changes may occur early in disease development. In conclusion, this comprehensive lipidomics study expands our knowledge of the lipid alterations associated with lupus, providing insights into disease pathogenesis and depleted lipids, which could serve as therapeutic targets.

Per- and polyfluoroalkyl substances (PFAS) are a growing concern due to their persistence, bioaccumulation potential, and continued widespread use in consumer products. PFAS disposed of in landfills are emitted to the environment via leachate, which drives a need to better understand PFAS behavior in landfills and landfill liner systems. This study examines PFAS concentrations in primary and secondary leachate from three municipal solid waste landfills utilizing double HDPE geomembrane liner systems. Samples were also analyzed for physical-chemical constituents such as chloride, ammonia, chemical oxygen demand, and metals. On average, physical-chemical parameter concentrations were significantly lower in the secondary compared to the primary leachate, although PFAS concentrations were not significantly different between leachate sources. Concentrations of chloride in groundwater and primary leachate were used to calculate expected PFAS concentrations in the secondary leachate. PFAS concentrations in secondary leachate were often higher than expected, with PFAAs more likely to exceed expected levels. Of the 92 PFAS analyzed, 50 were quantified in primary leachates and 48 in secondary leachates. The ∑PFAS concentrations in primary leachate ranged from 3200-81,000 ngL-1, and secondary leachate ranged from 3300-96,000 ngL-1. Possible explanations for the disproportionately high PFAS concentrations in secondary leachates, including residence time, transformation, liner sorption, and other PFAS sources (e.g., landfill gas) are explored. While liner systems are highly effective, PFAS migration through landfill liners and potential groundwater impacts remain a concern. This study underscores the importance of continued research into PFAS migration mechanisms and the potential environmental impacts of unidentified precursor PFAS in landfills.

Per- and polyfluoroalkyl substances (PFAS) have been widely detected in various environmental media, attracting significant research and regulatory attention. This preliminary study investigated the occurrence and maternal transfer of PFAS in pregnant sharks (n = 6) from Florida's coastal waters, encompassing a combined 101 embryos examined. Liver and muscle samples were collected from both adult mothers and embryos, with additional uterine fluid obtained from two species. The highest ∑PFAS concentration among the shark embryos was found in the liver of bonnethead (Sphyrna tiburo, 4.15 ± 0.16 ng/g ww, n = 8), followed by the great hammerhead (Sphyrna mokarran, 1.60 ± 1.07 ng/g ww, n = 57), Atlantic sharpnose (Rhizoprionodon terraenovae, 1.41 ± 0.38 ng/g ww, n = 2), and the tiger shark (Galeocerdo cuvier, 0.20 ± 0.20 ng/g ww, n = 34). The maternal transfer assessment revealed that perfluorooctanesulfonate and long-chain perfluoroalkyl carboxylic acids (C12-C14) accumulated in embryonic tissues of sharks, highlighting that these chemicals were transferred efficiently during gestation. Spearman's rank correlations showed a significant positive relationship between the maternal transfer ratio and the protein-water partition coefficient in select species, suggesting that the protein binding affinity of PFAS may enhance their transfer efficiency across the placental membrane.

PFAS are ubiquitous in the environment and have been detected in remote areas due to their persistence and potential long-range transport capabilities. We conducted a survey to explore the distribution of PFAS in surface water and wildlife from the Galapagos archipelago. Overall, 8 out of 21 PFAS were detected in 24 surface water samples, with PFOA and PFNA having the highest detection rates (79 % of samples). Plasma samples were obtained from marine iguanas (n = 24), black-striped salemas (n = 6), and Galapagos sea lions (n =14). Marine iguanas and black-striped salemas had only PFNA and PFTrDA quantified, respectively, whereas Galapagos sea lions exhibited a myriad of long-chain PFAS, with L-PFOS and PFCAs (C9 - C13) showing 100 % detection rates. Our results confirmed the presence of PFAS in the Galapagos archipelago, emphasizing that further research is needed to better understand the impact of these contaminants in suspected pristine and remote ecosystems.

Per- and polyfluoroalkyl substances (PFAS) are highly mobile and widespread chemicals that are associated with an expanding list of adverse health effects. Given their ubiquity and high mobility, dust has become a suitable matrix for assessing potential indoor levels of PFAS. Currently, vehicles represent a largely underexplored source of PFAS contamination in dust. We propose that vehicle cabin air conditioning (AC) filters can be used as opportunistic sampling devices for exploring PFAS levels in dust inherently present within vehicles. This study monitored 47 PFAS in cabin AC filters (n = 10) and engine air filters (as a comparison, n = 10) via high performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). Cabin AC filters, which filter air circulated within the passenger compartment, contained higher PFAS concentrations (median ∑PFAS = 92 ng g-1) than the engine air filters, which filtered outdoor air feeding into the vehicle engine (median ∑PFAS = 2 ng g-1). In cabin AC filters, the dominant PFAS were polyfluoroalkyl phosphate esters (PAPs), which accounted for 45% of ∑PFAS by concentration. In engine filters, the dominant PFAS were fluorotelomer sulfonic acids (dominated by one engine filter) and perfluoroalkyl carboxylic acids, which represented 59% and 20% of the ∑PFAS, respectively. This study demonstrated that we are likely exposed to PFAS inside vehicle cabins and that cabin AC filters are a well-suited sampling matrix worth further exploration.