Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies

Migration of chemical substances from packaging materials to food

At present, active food packaging is favored by manufacturers and consumers from all over the world for various special functions. However, the potential migration of chemical substances from the packaging into the food during contact is a significant concern. Therefore, a detailed discussion of this topic is warranted. This paper begins with a thorough analysis of the migration mechanisms, mathematical models, and critical parameters involved in the migration of chemical substances from food packaging. On this basis, it summarizes relevant detection techniques, the selection of food simulants, and risk assessment, which are crucial for the accuracy of migration test results. In addition, specific attention was focused on the migration of antimicrobial agents in food packaging. Finally, non-destructive testing methods, international legislation, and current opportunities and challenges were discussed. The research provides important guidance and inspiration for investigating the migration of chemical substances from food packaging to food.

Cost-effective magnetic Nylon 6 composites for extraction of perfluorinated compounds in water and bottled beverage followed with LC-MS/MS analysis

Perfluorinated compounds are of extensive concern due to their prevalent use, persistence, and toxicities. There is a demand for extraction adsorbents that are efficient, easy to synthesize, and cost-effective. Herein, a magnetic nylon 6 nanocomposite (M-Ny6) was synthesized through a simple process and utilized as an adsorbent in magnetic solid-phase extraction (MSPE) of perfluorooctanoic acid (PFOA). The MSPE condition was optimized and the adsorption characteristics for PFOA was investigated. Based on the interaction between the amide groups on M-Ny6 and PFOA, the MSPE method was coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for analyzing trace levels of PFOA in environmental water and bottled beverages. The established method demonstrated a detection limit of 1.2 ng L-1 with linear range across 50-800 ng L-1 and satisfactory recoveries (82.3-113.0 %) in spiked samples. The experimental results indicated that M-Ny6 is a promising and cost-effective MSPE adsorbent offering potential for large-scale applications in food analysis.

Perfluoroalkyl acids (PFAAs) and their precursors in sediments and adjacent riparian soils from the Three Gorges Reservoir, China: Contamination characteristics, source apportionment and ecological risks

Information on the occurrence and spatial distribution of perfluoroalkyl acids (PFAAs) and their precursors in sediments and adjacent riparian soils of Three Gorges Reservoir (TGR), which is one of the largest reservoirs in the world, is still limited. In this study, The total concentrations of these per- and polyfluoroalkyl substances (PFASs) ranged from 2220 to 19,300 pg/g in sediments and 298-9540 pg/g in soils. PFOA was the dominant PFAS in sediments and soils, accounting for 23.4% and 30.7% of the total median cocentrations of PFASs, respectively. PFAA precursors, such as 4:2 fluorotelomer sulfonate (4:2 FTS), 6:2 fluorotelomer sulfonate (6:2 FTS), and perfluorooctane sulfonamide (FOSA), were widely detected in sediments and soils. The distribution of PFASs exhibited distinct spatial variations and was more influenced by anthropogenic activities. Positive matrix factorization (PMF) identified fire-fighting foams (AFFF) and legacy fluoropolymer industry/textile treatment were the dominant sources in sediments (31.5%) and soils (30.8%), respectively. Finally, the ecological risk assessment showed that PFOS exhibited low to medium risks. Our findings indicate that the contamination of PFAA precursors must be considered when developing management measures to protect the TGR region.

Exposure to Legacy Per- and Polyfluoroalkyl Substances from Diet and Drinking Water in California Adults, 2018-2020

People are exposed to per- and polyfluoroalkyl substances (PFAS) through multiple sources, with diet historically considered a major source in general populations. This study characterized legacy PFAS in serum from 700 California adults and examined contributions from diet and drinking water. We applied robust regression to estimate associations between nontransformed serum PFAS concentrations, self-reported food consumption, and drinking water PFAS concentrations measured under the USEPA's third Unregulated Contaminant Monitoring Rule (2013-2015). Detectable drinking water concentrations were associated with increased serum perfluorooctanoic acid (PFOA) (0.26 ng/mL; 95% CI: 0.077, 0.43), perfluorohexanesulfonic acid (PFHxS) (0.64 ng/mL; 95% CI: 0.058, 1.23), and perfluorooctanesulfonic acid (PFOS) (0.39 ng/mL; 95% CI: -0.76, 0.86). Seafood consumption was associated with increased perfluorononanoic acid (PFNA) (0.013 ng/mL; 95% CI: 0.0058, 0.021), perfluorodecanoic acid (PFDeA) (0.0059 ng/mL; 95% CI: 0.0026, 0.0092), and perfluoroundecanoic acid (PFUnDA) (0.010 ng/mL; 95% CI: 0.0054, 0.015), while eggs were associated with increased PFDeA (0.0035 ng/mL; 95% CI: 0.00010, 0.0069) and PFNA (0.0073 ng/mL; 95% CI: 0.00017, 0.014). Findings could indicate that dietary contributions may be less than those in earlier studies conducted in other populations, possibly due to shifts in PFAS production over the past 20 years, and that drinking water remains an important source of exposure to PFOA and PFHxS in this population.

Diet quality in relation to serum perfluoroalkyl substance concentrations in Canadian preadolescents

BACKGROUND

Exposure to perfluoroalkyl substances (PFAS) is concerning because some of these chemicals are associated with health effects. Preadolescents eat more food per body weight and may be more affected by substances in food compared to adults.

OBJECTIVE

Estimate how diet quality and nutrients are associated with concurrently measured PFAS concentrations in Canadian preadolescents.

METHODS

Using data from 157 participants (7-11 years) in a Maternal-Infant Research on Environmental Chemicals follow-up study (2018-2021), we analyzed serum concentrations of 9 PFAS, and derived 2019-Healthy Eating Food Index (HEFI-2019) scores and nutrient intakes from 24-h diet recalls. We used multivariable linear regression to estimate cross-sectional associations between diet and serum PFAS concentrations.

RESULTS

Saturated fat consumption was associated with higher serum perfluorooctanesulfonic acid (PFOS) concentrations. The fruits and vegetables score was associated with higher perfluorodecanoic acid (PFDA), and perfluorononanoic acid (PFNA); similar associations appeared with the HEFI-2019 total score. Percentage of energy intake (%E) from protein was associated with lower perfluorooctanoic acid (PFOA), PFOS, and perfluorohexanesulphonic acid (PFHxS) while %E from fat was associated with higher PFDA and PFOS. Fiber and iron intakes were associated with higher PFHxS. Vitamin D intake was associated with lower PFNA.

CONCLUSIONS

We observed some associations between diet and PFAS. Our findings may be partially explained by toxicokinetics and PFAS presence in Canadian food systems. However, our interpretation is hindered by lack of temporality and potential confounding. Additional investigations which integrate food systems information paired with PFAS concentrations from food and biomonitoring are required.

Comprehensive Screening of Per- and Polyfluoroalkyl Substances (PFAS) in Food Contact Materials: Utilizing Combustion Ion Chromatography for Total Organic Fluorine (TOF) Analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) comprise thousands of fluorinated chemicals. They are of growing concern because many PFAS compounds are persistent and toxic. Food contact materials (FCMs) containing PFAS pose multiple exposure pathways to humans, prompting 12 states to enact laws banning FCMs with PFAS levels exceeding 100 ppm total organic fluorine (TOF).

OBJECTIVE

While LC-MS is often used to measure targeted PFAS compounds, much of the total PFAS content in the sample may be missed. To understand organic fluorine content in samples more comprehensively, we developed a method using combustion ion chromatography (CIC) to measure TOF and extractable organic fluorine (EOF) in FCMs.

METHODS

This technology utilizes combustion under an oxygen and argon atmosphere. All gaseous, acidic combustion products are collected in water, with ions separated on an ion-exchange column and detected by conductivity. Total fluorine (TF) was measured by combusting 10-50 mg FCM. Total inorganic fluorine (TIF) was measured by extracting cryo-ground FCM with water followed by direct injection to the ion chromatography (IC) system. TOF was then calculated by subtracting TIF from TF. EOF was determined by CIC after extracting analytes from the ground FCM using methanol-acetonitrile (80 + 20, by volume).

RESULTS

The method detection limit (MDL) for TOF is 0.51 ppm, exceeding the sensitivity requirements of current state regulations. A comparison of EOF to TOF revealed that EOF constitutes less than 15% of the TOF in the FCM samples.

CONCLUSION

TOF is a critical metric for assessing PFAS contamination in FCMs, as targeted LC-MS approaches may miss much of the PFAS in the samples.

HIGHLIGHTS

We developed a sensitive and automated method to determine TOF and EOF in FCMs. The method can be used to screen for PFAS in FCMs, ensuring compliance with current regulations on PFAS contamination.

Evidence for widespread human exposure to food contact chemicals

BACKGROUND

Over 1800 food contact chemicals (FCCs) are known to migrate from food contact articles used to store, process, package, and serve foodstuffs. Many of these FCCs have hazard properties of concern, and still others have never been tested for toxicity. Humans are known to be exposed to FCCs via foods, but the full extent of human exposure to all FCCs is unknown.

OBJECTIVE

To close this important knowledge gap, we conducted a systematic overview of FCCs that have been monitored and detected in human biomonitoring studies according to a previously published protocol.

METHODS

We first compared the more than 14,000 known FCCs to five biomonitoring programs and three metabolome/exposome databases. In a second step, we prioritized FCCs that have been frequently detected in food contact materials and systematically mapped the available evidence for their presence in humans.

RESULTS

For 25% of the known FCCs (3601), we found evidence for their presence in humans. This includes 194 FCCs from human biomonitoring programs, with 80 of these having hazard properties of high concern. Of the 3528 FCCs included in metabolome/exposome databases, most are from the Blood Exposome Database. We found evidence for the presence in humans for 63 of the 175 prioritized FCCs included in the systematic evidence map, and 59 of the prioritized FCCs lack hazard data.

SIGNIFICANCE

Notwithstanding that there are also other sources of exposure for many FCCs, these data will help to prioritize FCCs of concern by linking information on migration and biomonitoring. Our results on FCCs monitored in humans are available as an interactive dashboard (FCChumon) to enable policymakers, public health researchers, and food industry decision-makers to make food contact materials and articles safer, reduce human exposure to hazardous FCCs and improve public health.

IMPACT STATEMENT

We present systematically compiled evidence on human exposure to 3601 food contact chemicals (FCCs) and highlight FCCs that are of concern because of their known hazard properties. Further, we identify relevant data gaps for FCCs found in food contact materials and foods. This article improves the understanding of food contact materials' contribution to chemical exposure for the human population and highlights opportunities for improving public health.

PFAS regulations and economic impact: A review of U.S. pulp & paper and textiles industries

Public concern over per- and polyfluoroalkyl substances (PFAS) continues to grow as evidence highlights their persistence, bioaccumulation potential, and adverse health effects. Increasing detections in drinking water, consumer products, and industrial discharges have intensified regulatory scrutiny. This review examines the evolving PFAS regulatory landscape in the United States, focusing on the pulp, paper, and textiles industries, which contribute significantly to PFAS contamination through wastewater discharges, end-product disposal, and the absence of dedicated removal technologies. PFAS emissions from food packaging alone are estimated at 2,300 kg annually. Addressing contamination presents substantial economic challenges, with wastewater treatment costs projected to reach USD 3 billion annually and growing risks of legal liabilities exemplified by paper mill settlements reaching USD 11.9 million for historical pollution. Large-scale remediation of PFAS remains financially prohibitive, with estimates exceeding the global gross domestic product (GDP) of USD 106 trillion. Additionally, healthcare costs for PFAS-linked diseases exceed USD 62 billion and further emphasize the need for prevention. State-level restrictions on PFAS-containing consumer products are expanding, particularly in food packaging and textiles, which are now the most regulated across the United States. As PFAS-containing products face increasing market limitations and potential loss of sustainability certifications, which have already reduced sales growth by 70% in some cases, transitioning to non-fluorinated alternatives could significantly mitigate economic risks for paper and textiles companies. Within this context, this review highlights the urgency of integrating policy, technological innovation, and economic incentives to accelerate the transition away from PFAS and mitigate long-term environmental and financial liabilities.

Molecular Mechanisms of Perfluoroalkyl Substances Integration into Phospholipid Membranes

Understanding the molecular interactions of per- and polyfluoroalkyl substances (PFAS) with phospholipids is crucial for elucidating their pathological mechanisms and developing PFAS remediation strategies. In this study, we employ atomistic molecular dynamics simulations to examine PFAS insertion into phospholipid bilayers, including anionic perfluorooctanesulfonic acid (PFOS), perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA), and perfluorododecanoic acid (PFDoA), as well as neutral polytetrafluoroethylene (PTFE). Our study shows that PFAS insertion into lipid bilayers is driven by the free energy gradient between bulk water and the lipid membrane. Positively charged trimethylammonium groups of phospholipids attract negatively charged PFAS, overcoming the surface hydration barrier. Hydrophobic interactions between PFAS fluoroalkyl tails and lipid chains generate a significant driving force for PFAS reorientation and insertion. The increase in electrostatic potential across the lipid surface aids anionic PFAS insertion, but their dehydration hinders further movement. PFAS insertion enhances membrane ordering and decreases lipid fluidity, potentially affecting cellular functions by modifying membrane rigidity. The extended chain length of PFAS facilitates its interactions with the lipid membrane, resulting in a more pronounced influence on altering its structural and dynamic properties.

Interpretable machine learning models reveal the partnership of microplastics and perfluoroalkyl substances in sediments at a century scale

It is challenging to explore the complex interactions between perfluoroalkyl substances (PFASs) and microplastics in lake sediments. The partnership of perfluoroalkyl substances (PFASs) and microplastics in lake sediments are difficult to determine experimentally. This study utilized sediment cores from Taihu Lake to reconstruct the coexistence history and innovatively reveal the collaboration between PFASs and microplastics by using post-hoc interpretable machine learning methods. Microplastics and PFASs emerged in the 1960s and have significantly increased since the 1990s. PFASs and microplastics had the highest growth rate in the 0-10 cm range, with average growth rates of 35.96 pg/g/year and 4.40 items/year per 100 g, respectively. Extreme gradient boosting demonstrated the best simulation of PFASs and microplastics in machine learning models. Feature importance and Shapley additive explanations semi-quantitatively clarified the importance of transparent and pellet microplastics on PFASs concentrations, as well as the importance of perfluorooctane sulfonate (PFOS) and ΣPFASs on microplastics. Moisture content, redox potential, χfd, and χARM were the key influencing factors on contaminants. Partial dependence plots showed the influencing thresholds were 0.30 ng/g for ΣPFASs and 0.15 ng/g for PFOS on microplastics, and 10 items per 100 g for pellets and 12 items per 100 g for transparent plastics on PFASs. This study elucidated the interactions between two typical emerging contaminants on a century-scale through the intersection of environmental geochemistry and interpretable machine learning.

DART isotope dilution high resolution mass spectrometry and 19F-NMR detection of fluorotelomeric alcohols in hydrolyzed food contact paper

Fluorotelomer-based acrylate polymers and surfactants used to grease-proof food contact paper (FCP) are potential sources of dietary exposure to perfluoroalkyl substances (PFAS). Food contact substances (FCS) containing polyfluorinated long-chains (≥C8) were voluntarily removed by their manufacturers from the U.S. market in 2011 due to health concerns and largely replaced with FCSs containing short-chain (≤C7) PFAS. In 2020, FDA findings of potential biopersistence of 6:2 FTOH (CF3(CF2)5CH2CH2OH) similarly prompted an additional voluntarily phase-out of FCSs containing 6:2 FTOH by their manufacturers that was completed by the end of 2023. To monitor the phase-out process, a screening method was developed to detect FCPs containing ester-linked polyfluorinated pendant chains. Direct Analysis in Real Time-Isotope Dilution-High Resolution Mass Spectrometry (DART-ID-HRMS) enabled rapid semi-quantitative detection of 6:2 FTOH in FCP saponification reaction headspace without requiring sample concentration or chromatography. 19F-NMR analysis confirmed 6:2 FTOH pendant chain identity and detection dependence on saponification. The speed and specificity of this approach arise from ester saponification in the presence of stable isotopically labeled 6:2 FTOH; high FTOH differential volatility relative to nonfluorinated matrix, and the facile production of FTOH gas-phase anions (e.g., [M + O2]·-, [M-H + CO2]-) under ambient ionization conditions. The efficiency of this simple workflow makes it well-suited for monitoring the phase-out of FCS containing ester-linked polyfluorinated chains from the U.S. marketplace.

Food packaging solutions in the post-per- and polyfluoroalkyl substances (PFAS) and microplastics era: A review of functions, materials, and bio-based alternatives

Food packaging (FP) is essential for preserving food quality, safety, and extending shelf-life. However, growing concerns about the environmental and health impacts of conventional packaging materials, particularly per- and polyfluoroalkyl substances (PFAS) and microplastics, are driving a major transformation in FP design. PFAS, synthetic compounds with dual hydro- and lipophobicity, have been widely employed in food packaging materials (FPMs) to impart desirable water and grease repellency. However, PFAS bioaccumulate in the human body and have been linked to multiple health effects, including immune system dysfunction, cancer, and developmental problems. The detection of microplastics in various FPMs has raised significant concerns regarding their potential migration into food and subsequent ingestion. This comprehensive review examines the current landscape of FPMs, their functions, and physicochemical properties to put into perspective why there is widespread use of PFAS and microplastics in FPMs. The review then addresses the challenges posed by PFAS and microplastics, emphasizing the urgent need for sustainable and bio-based alternatives. We highlight promising advancements in sustainable and renewable materials, including plant-derived polysaccharides, proteins, and waxes, as well as recycled and upcycled materials. The integration of these sustainable materials into active packaging systems is also examined, indicating innovations in oxygen scavengers, moisture absorbers, and antimicrobial packaging. The review concludes by identifying key research gaps and future directions, including the need for comprehensive life cycle assessments and strategies to improve scalability and cost-effectiveness. As the FP industry evolves, a holistic approach considering environmental impact, functionality, and consumer acceptance will be crucial in developing truly sustainable packaging solutions.

Perfluorinated compounds linked to central precocious puberty in girls during COVID-19: an untargeted metabolomics study

Background and objective

The incidence of central precocious puberty (CPP) in girls increased significantly during the COVID-19 pandemic. This study aimed to explore the impact of perfluorinated endocrine disruptors on CPP through metabolomics analysis in girls from Hainan Province, China.

Methods

Serum samples from 100 girls with CPP and 100 healthy controls were collected. Untargeted metabolomics profiling was performed using ultra-high performance liquid chromatography coupled with quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive-Orbitrap-MS). Differentially expressed metabolites (DEMs) were screened, and pathway enrichment analysis was conducted.

Results

Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) revealed distinct metabolic profiles between the CPP and control groups. A total of 511 metabolites were identified, including 296 up-regulated DEMs and 255 down-regulated DEMs. Three perfluorinated compounds-PFSM-perfluoroalkyl_sulfonamide_Me, PFSM-FSAA, and PFCA-unsaturated-were significantly upregulated in the CPP group. KEGG pathway enrichment analysis suggested the involvement of multiple pathways in the CPP process regulated by these compounds.

Conclusions

Perfluorinated compounds may promote CPP in girls by interfering with various pathways and affecting the hypothalamic-pituitary-gonadal axis function. This study highlighted the need for further research and public health measures to address environmental endocrine disruptors.

Concentration-dependent cellular responses of coontail (Ceratophyllum demersum) during the substitutions to perfluorooctanoic acid by its two alternatives

The substitutions of alternatives to legacy per- and polyfluoroalkyl substances (PFASs) may lead to unknown and variational joint toxicity on ecosystems. To comprehensively understand the effects of substitutions on aquatic ecosystems, the single and joint effects of perfluorooctanoic acid (PFOA) and its alternatives (perfluorobutanoic acid, PFBA; 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3,heptafluoropropoxy)propanoic acid, GenX) with various concentrations and compositions on a primary producer, coontail (Ceratophyllum demersum), were investigated at cellular level. Results showed that the substitutions of PFBA/GenX could alleviate the inhibition of PFOA on plant length, hydrogen peroxide accumulation, and chlorophyll b, due to the shifts of reactive oxygen species and their less toxicity to antioxidants. Significant up-regulations of superoxide dismutase, glutathione, and carotenoid implied their primary roles in defensing against PFASs (p < 0.05). Catalase/peroxidase was significantly up-regulated in PFBA/GenX substitutions (p < 0.05) to help alleviate stress. PFBA substitutions reduced 23.9 % of PFOA in organelle and GenX reduced the subcellular concentrations of PFOA by 1.8-17.4 %. Redundancy analysis suggested that PFOA, PFBA, and GenX in cell wall and organelle, as well as GenX in soluble fractions, were responsible for the cellular responses. These findings were helpful to understand the integrated effects on aquatic ecosystems during the substitutions to legacy PFASs by alternatives.

Bioaccumulation mechanisms of perfluoroalkyl substances (PFASs) in aquatic environments: Theoretical and experimental insights

Per- and polyfluoroalkyl substances (PFASs) are persistent, bioaccumulative contaminants found in water resources at levels hazardous to human health. However, the PFAS bioaccumulation mechanism remains poorly understood. In this study, we incorporated density functional theory (DFT), molecular dynamics (MD), and experiments to analyze the partitioning pathways and to establish the structure-bioaccumulation relationship. DFT- and MD-calculated environmental fate parameters, comprising LogPO,W, LogPA,W, and diffusion coefficients, coincide with experiments at various ranges of PFAS molecules, with a correction coefficient (R²) of 0.783. MD simulations revealed that medium or long-chain-length PFASs spontaneously aggregate into submicelles in aquatic environments, enhancing their bioaccumulation effect. The short-chain PFASs show weak aggregation, but they also permeate into biological membranes. Particularly, it was discovered that aggregating PFASs "dissolve" into the lipid membrane matrix, owing significantly to van der Waals interactions rather than electrostatic effects. Thermodynamic analysis suggests that PFAS translocation involves spatial flips along the free energy surface. Short-chain PFASs exhibit low steric hindrance, contributing to bioaccumulation-a factor previously neglected in research. PFAS bioaccumulation depends on chain length, as further confirmed by intracellular reactive oxygen species formation and live/dead quantification in HepG2 cells. These insights advance our understanding of PFAS bioaccumulation mechanisms and highlight critical factors influencing their environmental and biological behavior.

Aggregation, Not Micellization: Perfluorooctanoic Acid, Perfluorobutanesulfonic Acid, and Potassium Perfluorooctanesulfonate Behavior in Aqueous Solution

Surface tension, conductivity, and dynamic light scattering (DLS) measurements were used to examine the surface and bulk solution behaviors of three members of the PFAS family, perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS), and the potassium salt of perfluorooctanesulfonic acid (PFOS). Measurements were carried out in solutions having variable (acidic) pH and in solutions buffered to pH = 8.0. Surface tension data show traditional soluble surfactant behavior, and results illustrate that PFOA, PFBS, and PFOS surface activity depends sensitively on solution phase pH. The tightly packed monolayers formed by PFOA in mildly acidic solutions imply that the surface pH of PFOA solutions is several units lower than bulk. Results from conductivity experiments generally show increasing conductivity with increasing bulk solution surfactant concentration. In pH = 8.0 solutions, changes in conductivity slope with surfactant concentration suggest the onset of micelle formation at concentrations <1 mM, markedly lower than reported in literature. In general, apparent critical micelle concentrations (CMCs) determined from conductivity data agree with similar predictions made from surface tension results. DLS measurements show that at concentrations close to the predicted PFAS CMCs, objects with diameters ≤10 nm start to form. However, unlike micelles, these objects continue to grow with increasing bulk solute concentration. These aggregates form structures having diameters of 50-150 nm. Aggregate size shrinks modestly as solution phase temperature increases, and this behavior is reversible. Cryo-EM images of PFOA solutions confirm a broad distribution of particles, supporting the DLS measurements. Findings reported in this work represent the first evidence that these three EPA-regulated PFAS surfactants form aggregates rather than micelles in solution. Findings also begin to reconcile differences in reported surface behaviors that have led to CMC predictions in the literature varying by more than an order of magnitude.

Leaching of per- and polyfluoroalkyl substances (PFAS) from food contact materials with implications for waste disposal

Leaching of per- and polyfluoroalkyl substances (PFAS) during the post-consumer disposal of food contact materials (FCMs) poses a potential environmental threat but has seldom been evaluated. This study characterized the leaching behavior of PFAS and unidentified precursors from six common FCMs and assessed the impact of environmental conditions on PFAS release during disposal. The total concentration of 21 PFAS ranged from 3.2 to 377 ng/g in FCMs, with PFAS leachability into water varying between 1.1-42.8 %. Increasing temperature promoted PFAS leaching, with leached nine primary PFAS (∑9PFAS) reaching 46.3, 70.4, and 102 ng/L at 35, 45, and 55 ℃, respectively. Thermodynamic analysis (∆G>0, ∆H>0, and ∆S<0) indicated hydrophobic interactions control PFAS leaching. The presence of dissolved organic matter in synthetic leachate increased the leached ∑9PFAS from 47.1 to 103 ng/L but decreased PFBS, PFOS, and 6:2 FTS leaching. The total release of seven perfluorocarboxylic acids (∑7PFCAs) from takeaway food packaging waste was estimated to be 0.3-8.2 kg/y to landfill leachate and 0.6-15.4 kg/y to incineration plant leachate, contributing 0.2-4.8 % and 0.1-3.2 % of total ∑7PFCAs in each leachate type. While the study presents a refined methodology for estimating PFAS release during disposal, future research is needed on the indirect contribution from precursors.

Effects of perfluoroalkyl sulfonic acids on developmental, physiological, and immunological measures in northern leopard frog tadpoles

The chronic toxicity of short chain perfluoroalkyl sulfonic acids (PFSAs), such as perfluorobutanesulfonic acid (PFBS) and perfluorohexanesulfonic acid (PFHxS), are relatively understudied despite the increasing detection of these compounds in the environment. We investigated the chronic toxicity and bioconcentration of PFBS and PFHxS using northern leopard frog (Rana [Lithobates] pipiens) tadpoles. We exposed Gosner stage (GS) 25 tadpoles to either PFBS or PFHxS at nominal concentrations of 0.1, 1, 10, 100, and 1000 μg/L until metamorphosis (GS42). We then assessed tadpole growth, development, stress, and immune metrics, and measured fatty acid (FA) composition and PFSA concentrations in liver and whole-body tissues. Tadpole growth and development measures were relatively unaffected by PFSA exposure. However, tadpoles exposed to 1000 μg/L PFBS or PFHxS had significantly increased hepatosomatic indexes (HSI) relative to controls. Further, tadpoles from the 1000 μg/L PFHxS treatment had altered FA profiles relative to controls, with increased total FAs, saturated FAs, monounsaturated FAs, and omega-6 polyunsaturated FAs. In addition, tadpoles from the 1000 μg/L PFHxS treatment had a higher probability of waterborne corticosterone detection. These results suggest that PFBS and PFHxS influence the hepatic health of tadpoles, and that PFHxS may alter lipid metabolism in tadpoles. We also observed a higher probability of tadpoles being phenotypically female after exposure to an environmentally relevant concentration (0.1 μg/L) of PFHxS, suggesting that PFHxS may exert endocrine disrupting effects on tadpoles during early development. The measured bioconcentration factors (BCFs) for both compounds were ≤10 L kg-1 wet weight, suggesting low bioconcentration potential for PFBS and PFHxS in tadpoles. Many of the significant effects observed in this study occurred at concentrations several orders of magnitude above those measured in the environment; however, our work shows effects of PFSAs exposure on amphibians and provides essential information for ecological risk assessments of these compounds.