Perfluoroalkyl Substances Research Articles

From wastewater to feed: Understanding per- and polyfluoroalkyl substances occurrence in wastewater-irrigated crops.

Reusing treated wastewater for irrigation is a sustainable way to recycle nutrients and reduce freshwater use. However, wastewater irrigation inadvertently introduces per- and polyfluoroalkyl substances (PFAS) into agroecosystems, causing concerns regarding potential adverse effects to ecosystem, animal, and human health. Therefore, a better understanding of the pathways by which PFAS accumulate in forage crops is needed. A greenhouse study was conducted to (1) quantify the contribution of root uptake versus foliar sorption of PFAS in corn (Zea mays) and orchard grass (Dactylis glomerata), (2) assess effects of PFAS-impacted wastewater irrigation on plant health, and (3) determine the potential implications for bioaccumulation. The greenhouse study was composed of four treatments for each forage crop to isolate the relative contribution of two uptake pathways. Results suggested that foliar sorption was an unlikely contributor to PFAS concentrations observed in crop tissue. Root uptake was identified as the predominant uptake pathway. PFAS were detected more frequently in orchard grass samples compared to corn silage samples. Additionally, corn exhibited a lower uptake of long-chain PFAS compared to grass. Overall, no plant health effects on growth attributable to PFAS concentrations were observed.Forage data suggest cattle exposure to PFAS would be largely short-chain PFAS or long-chain "replacement" compounds(>50%). However, cattle may still be exposed to potentially harmful long-chain PFAS; levels in the forage crops exceeded the tolerable weekly intake set by the European Food Safety Authority. This study provides insights on PFAS entry into the food chain and potential implications for livestock and human health.

Toxic-Free Environment: Forever Chemicals Removal from Water and Wastewater

Per- and polyfluoroalkyl substances (PFAS), commonly known as "forever chemicals," are persistent synthetic compounds that have been widely utilized since the mid-20th century across various industries. Due to their environmental persistence and potential health risks, PFAS has become a significant concern, particularly in relation to water and wastewater contamination. This paper investigates the complex challenges associated with PFAS, focusing on existing regulatory frameworks, treatment strategies, and innovative clean technologies that aim to reduce or eliminate these harmful substances. The study emphasizes the importance of advanced treatment methods such as electrochemical degradation, nanofiltration, adsorption, and biodegradation, each offering varying degrees of success. Despite advancements in treatment technologies, prevention remains the most effective strategy to minimize PFAS pollution. The paper calls for collaborative efforts from regulatory bodies, industries, and communities to implement more sustainable practices, ensuring a toxic-free environment and aligning with circular economy principles. Continuous research and international cooperation are crucial for developing effective long-term solutions to address PFAS contamination and safeguard both public health and the environment.

Kinetics of 15 per- and polyfluoroalkyl substances (PFAS) after single oral application as a mixture – A pilot investigation in a male volunteer

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with half-lives in humans in the range of years in case of the long-chain compounds, leading to accumulation and measurable levels in plasma. In contrast, short-chain and “alternative” PFAS have lower levels or are not detectable in humans with background exposure. This may be due to lower exposure, but also due to much shorter half-lives compared to long-chain compounds. To get better data on kinetics, a healthy volunteer orally ingested a mixture of fifteen predominantly 13C-labeled PFAS (“MPFAS”) in a pilot investigation (MPFBA, MPFPeA, MPFHxA, MPFHpA, MPFOA, MPFNA, MPFDA, MPFUdA, MPFDoA, PFBS, MPFHxS, MPFOS, DONA, HFPO-DA, 6:2FTS). After application, concentrations were measured over 450 days in plasma, urine and feces, using UHPLC-MS/MS analysis after extraction. The compounds were absorbed quickly and almost completely. Data analysis revealed volumes of distribution between 110 and 177 mL/kg bw for most compounds, but higher values for MPFDA, MPFUdA and MPFDoA (maximum of 354 mL/kg bw). Half-lives were found to vary extremely, from 0.5 days (MPFPeA) and 1.5 days (MPFHxA) to 51 days (PFBS) and 152 days (MPFHpA) in case of the short-chain and “alternative” compounds. For the long-chain compounds, half-lives in the range of several years were confirmed for MPFOA, MPFNA, MPFHxS and MPFOS, but with even higher chain-lengths of the carboxylic acids, the half-lives were found to decrease, with the shortest half-life for MPFDoA (295 days). Elimination from the body was completely explained by the urinary losses in case of the short-chain and “alternative” PFAS, and in part by the fecal losses in case of the long-chain PFCA. Overall, elimination kinetics seem to be determined by several different renal and gastrointestinal factors (fraction unbound in plasma, binding affinity to organic anion transporters causing netto secretion or reabsorption, fecal loss with mechanisms to be clarified).

Evaluation of per- and polyfluoroalkyl substances (PFAS) toxic effects on the acute inflammatory response in the medicinal leech Hirudoverbana

Per- and polyfluoroalkyl (PFAS) substances are a large group of chemicals with elevated water and oil-resistance properties, widely implicated in various applicative fields. Due to the extensive use and high resistance to degradative factors, these compounds pose a significant risk of environmental spreading, bioaccumulating also in living organisms. In this context, despite many researches have been performed to demonstrate “legacy” PFAS harmfulness, only few data are still available about all the emerging fluorinated molecules, industrially introduced to replace the previous ones. For this reason, we proposed the medicinal leech Hirudo verbana as consolidated invertebrate model to assess the effects of four different PFAS (HFPO-DA, PFMoBa, PFOA and PFMOPrA) following freshwater dispersion. Morphological, immunohistochemical and molecular analyses demonstrate that, despite all the compounds basically induce an acute inflammatory and oxidative stress response, a different cellular and molecular response has been observed. Whereas for PFOA and PFMOPrA an increase in the tested concentration leads to a corresponding rise in the immune response, HFPO-DA and PFMoBa trigger an entirely opposite effect. Indeed, the significant recruitment of both granulocytes and macrophage like cells, typically involved in the removal of non-self, is inhibited with increasing concentrations of these compounds. The data collected revealed a different sensitivity of the leech immune system following PFAS exposure, requiring to deepen the current knowledge on the potential toxicity of these compounds.

A Conceptual Site Model for Per‐ and Polyfluoroalkyl Substance Water Supply Impacts in a Residential Community

ABSTRACTAt a Class 4 State Superfund site located in a densely developed residential/commercial area in a suburb of New York City, emerging contaminant sampling for PFAS was performed as part of a statewide data‐gathering project. Two per‐ and polyfluoroalkyl substances (PFAS), perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), were detected at concentrations in excess of drinking water standards in bedrock and overburden monitoring wells at the State Superfund site. A bedrock private water supply well sampling program and a PFAS source investigation, consisting of overburden investigations near potential sources (i.e., sites with a history of known or suspected use, storage, or discharge of PFAS), were undertaken to assess exposures and identify and potentially eliminate sources of PFAS contaminants in the bedrock drinking water supply.Relative ratios of PFAS (i.e., PFAS signatures) were plotted geospatially to facilitate comparison of the characteristics of overburden groundwater sampling results to that of nearby bedrock private water supply sampling results. In addition, total PFAS concentrations in overburden groundwater and bedrock private water supply samples were compared to identify potential sources of bedrock groundwater impacts. The PFAS signature analysis revealed that (1) PFAS signatures of overburden groundwater samples were generally consistent with nearby bedrock private water supply samples; (2) total PFAS concentrations detected in overburden groundwater samples were marginally higher than concentrations detected in nearby bedrock private water supplies; (3) there was generally low variability in PFAS signatures throughout the study area (Assessment Area); and (4) overburden groundwater and bedrock private water supply PFAS signatures were similar to that of the nearby wastewater treatment plant effluent discharge, which represents a composite average PFAS signature for domestic wastewater from the area. Finally, septic system tracers were also detected in bedrock private water supply and overburden groundwater samples. Based on the results of the investigation, multiple lines of evidence support the Conceptual Site Model, which is likely applicable to many PFAS‐contaminated drinking water supplies with conditions similar to the Assessment Area: consumer product use and discharge to domestic septic systems in a densely developed residential area, lacking area‐wide municipal water and sewer, with shallow groundwater and bedrock, and a vertical downward groundwater gradient, have resulted in the widespread presence of PFAS in private water supply wells.

Efficient removal of per- and polyfluoroalkyl substances (PFASs) from stored rainwater by composite metal salt /polydimethyldiallylammonium chloride coagulants

Stored rainwater, the primary source of drinking water in the villages and towns of the Loess Plateau in northwest China, has been found to contain per- and polyfluoroalkyl substances (PFASs) and lacks necessary treatment measures. Coagulation is a common water treatment process, and enhancing its efficacy in removing PFASs can significantly improve treatment efficiency, reduce costs, and minimize the environmental and health risks associated with perfluorinated compounds. This study investigated the removal efficiency of perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) using inorganic salt coagulants alone and in combination with polydimethyldiallylammonium chloride (PDMDAAC). The results indicated that the removal efficiencies of the four PFASs by polyferric chloride (PFCl) and polyaluminum chloride (PACl) increased with alkalinity. PDMDAAC significantly enhanced the coagulation removal efficiency of the four PFASs. The removal efficiency of the four PFASs was highest when the raw water pH was near 7. Within the molecular weight range of 0–500,000 for PDMDAAC, the removal efficiency of the four PFASs increased with increasing molecular weight. Charge neutralization is the primary coagulation mechanism for the removal of anionic PFASs. Therefore, this study provides guidance for selecting coagulants to remove PFASs from stored rainwater.

Determination of per- and polyfluoroalkyl substances (PFAS) in six different fish species from Swiss lakes

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants with bioaccumulation potential, particularly affecting aquatic ecosystems and human health also via fish consumption. There is therefore a need for reliable extraction methods and studies to accurately assess PFAS levels in fish, crucial for understanding bioaccumulation and potential toxicological effects on both fish and humans through consumption. This study investigated PFAS levels in freshwater fish from Swiss lakes, focusing on six common species: Coregonus wartmanni, Cyprinus carpio, Oncorhynchus mykiss, Perca fluviatilis, Salmo trutta, and Squalius cephalus. Utilizing an optimized QuEChERS extraction method, 15 PFAS were analyzed in 218 fish fillet samples using liquid chromatography-mass spectrometry (LC–MS/MS). The results were compared to EU regulations and EFSA guidelines for tolerable weekly intake (TWI), with a specific focus on correlations between fish size and PFAS concentration. Our findings reveal significant PFAS contamination, particularly in Perca fluviatilis with perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS) levels often exceeding EU safety limits. TWI, calculated for a person of 70 kg body weight and an intake of 200 g of fish fillet, is exceeded in 95% of Coregonus wartmanni, 100% of Squalius cephalus, and in 55%, 50%, and 36% of the specimens Oncorhynchus mykiss, Salmo trutta, and Perca fluviatilis respectively. Correlation analysis between PFAS concentration and fish size in 121 Salmo trutta specimens revealed significant positive correlations for perfluorobutane sulfonic acid (PFBS), perfluorodecanoic acid (PFDA), and perfluorohexane sulfonic acid (PFHxS), and a negative correlation for perfluoropentanoic acid (PFPeA). These results underscore the critical need for continuous monitoring and regulatory efforts to mitigate PFAS exposure risks to both ecosystems and human health.

A Comprehensive Review of the Occurrence, Distribution, Characteristics and Fate of Per- and Polyfluoroalkyl Substances in the African Continent

AbstractPer- and polyfluoroalkyl substances (PFAS) represent synthetic organic compounds extensively utilized in a variety of domestic and industrial products due to their distinctive characteristics. Designated as persistent organic pollutants (POPs) by the Stockholm Convention, PFAS are recognized for their long-lasting presence, widespread prevalence, and adverse impacts on both the environment and human health. Recently, the United States Environmental Protection Agency (US EPA) revised the guideline limits for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in drinking water, setting them at 0.02 and 0.004 ng/L, respectively. Despite the global emphasis on the necessity for monitoring and treating PFAS in environmental media, there is a scarcity of information on PFAS studies in Africa. This gap may be attributed to a lack of modern laboratory facilities, weak governance, and the enforcement of environmental regulations. This study comprehensively reviews PFAS, focusing on key areas such as global guidelines and regulations, sources and distribution in the environmental matrix in Africa, characteristics, environmental fate, reported methods for sampling and analysis in Africa, and the role of government in the National Implementation Plan (NIP) on the continent. Additionally, the study offers recommendations and identifies knowledge gaps. In Africa, PFAS have been detected in various environmental compartments, including drinking water ranging from 0.03 to 200 ng/L, surface water ranging from 0.0254 to 788 ng/L, sediment ranging from 0.50 to 248.14 ng/g, wastewater ranging from 0.9 to 507 ± 257.6 ng/L, seafood ranging from 0.12 to 179.2 ng/g, sludge ranging from 0.01 to 0.098 ng/g, plants ranging from 0.160 to 29.33 ng/g, and indoor dust ranging from 1.3 to 69 ng/g. Notably, perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are prevalent in samples from various environmental matrices across Africa. Reported sources of PFAS in African countries include municipal waste, hospital waste from medical equipment, discharge from industries, and wastewater treatment plants. Urgent attention is required from decision-makers and researchers in Africa to address PFAS monitoring, regulation, and treatment within the continent. Graphical abstract

Bridging the Technology Gap for Cost‐Effective and Sustainable Treatment of Per‐ and Polyfluoroalkyl Substances in Surface Water and Stormwater

ABSTRACTThis article addresses the urgent need for cost‐effective and sustainable methods to mitigate per‐ and polyfluoroalkyl substances (PFAS) contamination in surface water and stormwater. Although the majority of PFAS research and development to date has focused on groundwater and soil treatment technologies, in some cases there may be a greater risk posed by the high mobility and potential for direct contact with PFAS in surface water and stormwater. Based on the evolving regulatory landscape and the elevated PFAS concentrations observed in available stormwater data near some fire training facilities, additional attention to this topic is needed to support the development of effective and practical treatment technologies for PFAS in surface water and stormwater. We propose addressing the need to bridge the current technology gap between (1) expensive mechanical and/or construction‐intensive technologies and (2) the development of cost‐effective and sustainable surface water and stormwater PFAS treatment options. We envision a future where nature‐based approaches could be employed for stand‐alone PFAS treatment. Alternatively, nature‐based approaches could be used for initial PFAS mass removal as a pretreatment step within a treatment train followed by engineered adsorbents or other technologies, if needed to achieve low concentration cleanup thresholds. We provide an example of a potential nature‐based treatment train that would rely on the natural propensity of PFAS to accumulate in surface water foams using foam‐enhancing weirs and flumes (FWFs), combined with the demonstrated treatment potential of constructed floating wetlands (CFWs). Additional research into the validation, optimization, and site‐specific design factors of nature‐based treatment trains, such as the FWF+CFW approach, warrants future research and development.

Aggregated health risk assessment of perfluoroalkyl acids migrated from convenience food contact materials.

Ingestion of perfluoroalkyl acids (PFAAs) via contaminated food contact materials (FCMs) is an important human exposure source. This study adopts a toxicity equivalent approach to evaluate the collective health risk of multiple PFAAs in FCMs. A comprehensive extraction and analysis of 21 PFAAs in FCMs was performed. Among the analyzed substances, 15 PFAAs were detected. Migration experiment using three food simulants revealed the migration range of seven PFAAs from FCMs into the simulant to be 0.47-46.7ng/cm2. The hazard quotient results suggest minimal health risk, except for 9% of packaged samples where perfluorooctanoic acid (PFOA) poses a higher risk. Utilizing PFOA toxic equivalent concentrations, comprehensive risk calculations showed ∼77% of samples potentially posing elevated health risks due to PFAA exposure. This emphasizes the substantial contribution of PFAAs beyond PFOA and underscores the importance of considering them in related assessments. The aggregated risk assessment reflects actual exposure circumstances more accurately.

Serum concentrations of per- and polyfluorinated substances and risk of B-cell non-Hodgkin lymphoma

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants that are detectable in the serum of most U.S. adults. Some studies of highly-exposed individuals have suggested positive associations between PFAS and B-cell non-Hodgkin lymphoma (B-NHL). To investigate whether associations exist at lower exposure levels, we conducted a nested case-control study investigating serum PFAS concentrations and B-NHL within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. We measured pre-diagnostic serum concentrations of five PFAS among 706 cases (age at diagnosis = 55–93 years, median 73 years) and 706 controls individually matched on age at blood draw, sex, self-reported race and ethnicity, study center, and year of blood collection (the median follow-up years = 10). We estimated odds ratios (ORs) and 95 % confidence intervals (CIs) for PFAS concentrations in relation to B-NHL, both overall and for selected histologic subtypes [diffuse large B cell lymphoma (DLBCL), follicular lymphoma (FL), and marginal zone lymphoma (MZL)] using conditional logistic regression. We found no evidence of a positive association with B-NHL for any of the five PFAS. In analyses of histologic subtypes, perfluorohexane sulfonate (PFHxS) was significantly associated with DLBCL in a model adjusting for all other PFAS (OR for highest vs. lowest quintile = 2.19, 95 % CI = 1.21, 3.95; Ptrend = 0.02), but not in a model without mutual adjustment (OR = 1.37, 95 % CI = 0.82, 2.29; Ptrend = 0.26). We also observed an inverse association between perfluorononanoate and DLBCL (mutually-adjusted OR = 0.83, 95 % CI = 0.69, 0.99 per doubling in concentration), although the association was null among participants with blood drawn prior to 1997 (OR<1997 = 1.00, 95 % CI = 0.82, 1.21; OR≥1997 = 0.65, 95 % CI = 0.53, 0.79; Pinteraction = 0.0003). In conclusion, our findings from a prospective cohort study with PFAS serum concentrations comparable to that of the general population do not support an association with increased risk of B-NHL overall. The suggestive evidence of a positive association between PFHxS and DLBCL warrants further investigation.

Per- and polyfluoroalkyl substances in food and beverages: determination by LC-HRMS and occurrence in products from the Belgian market

Per- and polyfluoroalkyl substances (PFAS) are industrial chemicals encompassing thousands of compounds. Due to their persistent, bioaccumulative and toxic character, PFAS have become environmental contaminants, and exposure to these chemicals may lead to adverse health effects. This study aimed to provide a sensitive analytical method for the quantification of 25 PFAS in food including food for the young population and beverages, and to gather the missing occurrence data for the dietary exposure evaluation for the Belgian population. More than a decade ago, such assessment was performed only for PFOS and PFOA and is currently outdated. For the determination of PFAS in foodstuffs, an extraction based on a “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) protocol and combined with a two-step purification using solid-phase extraction (SPE) was optimised. The quantitative analysis was performed by liquid chromatography high-resolution mass spectrometry (LC-HRMS). The method was validated, and the achieved limits of quantification (LOQs) ranged from 0.002 to 0.3 μg/kg, with the exception of HFPO-DA (1 μg/kg). The LC-HRMS analysis of 268 food products from the Belgian market demonstrated that 43% of samples contained at least one PFAS with a maximum of eleven PFAS measured in a stew of wild pork. PFOS was the most detected compound found in 19% of samples, followed by PFBA (18%) and PFOA (15%), while PFTeDA, PFPeS, PFHpS, PFDS, PFUnDS, PFDoDS, PFTrDS, Minor F53B and HFPO-DA were not detected. The concentrations of the different PFAS in commercial food varied from <LOQ to 2.85 μg/kg, with only one crab sample exceeding the maximum level for PFOA set by the Commission Regulation (EU) 2023/915.

Associations of pre- and postnatal per- and polyfluoroalkyl substance exposure with adolescents' eating behaviors.

Per- and polyfluoroalkyl substances (PFAS), persistent environmental chemicals, may act as obesogens by interacting with neuroendocrine pathways regulating energy homeostasis and satiety signals influencing adolescent eating behaviors. In 211 HOME Study adolescents (Cincinnati, OH; recruited 2003-2006), we measured PFAS concentrations in serum collected during pregnancy, at delivery, and at ages 3, 8, and 12 years. Caregivers completed the Child Eating Behavior Questionnaire (CEBQ) at age 12, and we calculated food approach and food avoidance scores. Using quantile-based g-computation, we estimated covariate-adjusted associations between a mixture of four gestational PFAS and CEBQ scores. We identified high (n = 76, 36%) and low (n = 135, 64%) longitudinal PFAS mixture exposure profiles between delivery and age 12 years using latent profile analysis and related these to CEBQ scores. We examined whether child sex or physical activity modified these associations. We observed no association of gestational PFAS mixture with food approach or food avoidance scores. Children in the higher longitudinal PFAS mixture profile had slightly higher food approach scores (β: 0.47, 95% CI: -0.27, 1.23) and similar food avoidance scores (β: -0.15, 95% CI: -0.75, 0.46) compared with children in the lower profile. We found some evidence that higher physical activity favorably modified the association between longitudinal PFAS mixture profiles and emotional overeating (interaction P value = 0.13). Child sex did not consistently modify any associations. Serum PFAS concentrations were not consistently linked to adolescent eating behaviors in this study, suggesting alternative pathways, such as metabolic rate, may underlie previously observed associations between PFAS exposure and childhood obesity.

Insights into PFAS contaminants before and after sewage discharges into a marine protected harbour

Per and polyfluoroalkyl substances (PFAS) and their degradation products are a concern to human and ecosystem health. Wastewater treatment plants are not efficient at removing PFAS compounds and are thought to be a major source of these compounds to marine environments. The sewerage infrastructure in the UK, has over 20,000 combined stormwater overflows (CSOs). These CSOs are relief values whereby untreated wastewater can discharge under permit from the Environment Agency with exceptional rain/snowfall conditions. CSOs discharged 3.6 million monitored hours of untreated wastewater into English rivers and coasts in 2023. Concerns have been raised about the proximity of these CSO discharges to highly protected marine habitats. This study is the first to determine that PFAS concentrations are elevated in a highly protected marine bay (Langstone Harbour, England) following recent sewage releases compared to an extended period without discharge. Analysis was carried out into a suite of 54 PFAS compounds of which only one (PFHpA) was detectable above LOD prior to discharges but 8 afterwards. These included banned PFOS (Linear and Branched 8.6 ng/L ∓ 0.90) and PFOA (2.9 ng/L ∓ 0.29) which were above annual average EQS for inland and ‘other’ surface waters. Most of the PFAS compounds detected doubled in concentration above LODs. These two-fold increases we discuss are likely conservative estimates based on the use of LODs and tidal conditions. Additional Oysters (Crassostrea gigas) and Seaweed (Fucus vesiculosus) were taken revealing high concentrations of the shorter chain PFBA (6.99μg/kg ∓ 2.42 ww) in seaweed samples. These seaweeds were calculated to have conservative bioaccumulation factors (BAF) > 6000 for PFBA indicating these algae might be an important reservoir of some PFAS contamination. We discuss these results in the context of the largescale discharges of untreated wastewater nationally and globally, and call upon a need for a better understanding of the transfer of PFAS contaminants into marine food chains.

Comparison of Environmental Footprint for Per‐ and Polyfluoroalkyl Substances Liquids and Solids Treatment Technologies

ABSTRACTPer‐ and polyfluoroalkyl substances (PFAS) contamination is a critical worldwide issue due to their widespread industrial use and persistence in the environment. PFAS treatment technologies are being applied to address the challenges associated with these substances. Selection of the appropriate treatment technology requires the assessment of many variables before full‐scale implementation. Factors such as cost, effectiveness, availability, and expected treatment duration are commonly considered; however, it is important to also consider the environmental footprint, which is the impact on the environment from the energy and materials used in implementing the treatment technology itself. The low PFAS treatment levels promulgated thus far, such as US Environmental Protection Agency drinking water Maximum Contaminant Levels of 4 ng/L for perfluorooctane sulfonate and perfluorooctanoic acid, as well as future low cleanup standards for other compounds and impacted media, will require long‐term remedial actions. Understanding the environmental impacts for PFAS treatment technologies can provide additional insights to be considered during the remedy selection. The authors conducted a comparison study of a wide range of PFAS treatment technology types for both liquids and solids, operating under limited but realistic hypothetical scenarios. The results present the approximate expected greenhouse gas (GHG) emissions of each technology type and scenario, compared to one another for the treatment of two key target compounds: perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). The liquid treatment technology types considered in this evaluation include technologies that concentrate or separate PFAS from the liquid media (such as ion exchange, granular activated carbon, and foam fractionation), technologies that destroy PFAS (such as supercritical water oxidation and electrochemical oxidation), and landfill disposal via solidification. In practice, remedial solutions for a given site might include both a concentration/separation step and a destruction step. These combinations were not evaluated in this comparison. The solids treatment technologies considered included thermal desorption, soil washing, soil stabilization, and excavation and disposal at a landfill. The factors included in each scenario were material production, material and equipment transportation, equipment and energy use, and material disposal, as these were considered to be the largest contributors to GHG emissions.

In Vitro Per- and Polyfluoroalkyl Substances (PFAS) Adsorption Assessment through Mesoporous Styrene-Divinylbenzene Sorbent Cartridge

In Vitro Per- and Polyfluoroalkyl Substances (PFAS) Adsorption Assessment through Mesoporous Styrene-Divinylbenzene Sorbent Cartridge

The influence of functional groups on the pyrolysis of per- and polyfluoroalkyl substances

Thermal treatment is a widely used remediation strategy for PFAS-contaminated materials such as soil, spent sorbents, and domestic waste. To better understand the effectiveness and environmental impact of thermal treatments for PFAS-contaminated materials, a fundamental understanding of PFAS thermal degradation mechanisms is required. This work aims to study the pyrolysis of six representative PFAS compounds, all of which have an eight-carbon length but with different functional groups. To assess the thermal stability and pyrolysis products of these six PFAS compounds, evolved gas analysis (EGA) was performed using thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) coupled with an infrared spectrometer (IR) and a mass spectrometer (MS), as well as pyrolysis-GCMS (Pyr-GCMS). The EGA data demonstrates that compounds with lower estimated vapor pressures were generally found to be more thermally labile, and the presence of an ionic bond necessitates higher temperatures for pyrolysis. Pyrolysis at 900 °C yielded a variety of fluorinated organic compounds at significant signals. Tetrafluoroethene constituted the majority of the Pyr-GCMS signal for all the compounds. Moreover, a significant fraction of detected products was unable to be identified, underscoring a need for better tools to help with the identification of unknowns. Pyrolysis can occur through random chain scission, scission of the functional group, scission of the terminal CF3 group, and HF elimination. Some compounds may undergo more complete beta-scission to produce smaller pyrolysis products compared to others. The presence of acidic protons within the functional group can help facilitate HF elimination, whereas the salt form of a PFAS compound is less likely to undergo HF elimination. Termination of radical intermediates can either be recombination with a CF3 radical or hydrogen abstraction (H-abstraction). Observed hydrogen-substituted products indicate that functional groups with higher hydrocarbon character may lead to more H-abstraction terminated products. Overall findings show that the functional group of a PFAS may decrease or increase its thermal stability and lead to different profiles of pyrolysis products.

Transition-metal-free defluorinative cyclization of perfluoroalkyl alkenyl iodides with C,N-dinucleophiles: Synthesis of (E)-perfluoroalkenyl pyrroles

Functionalization of the C-F bond in perfluoroalkyl substances represents an emerging focus in organic chemistry. We report here a transition-metal-free intermolecular defluorinative cyclization of perfluoroalkyl alkenyl iodides with C,N-dinucleophiles. This method enables highly chemo-, regio-, and stereoselective 2-fold C (sp3)-F bond cleavage at two vicinal carbon centers in the perfluoroalkyl chain, resulting in the assembly of a five-membered N-heterocycle with a structurally privileged (E)-prefluoroalkenyl unit. The success of partial defluorination is mainly attributed to the pre-installed alkenyl functionality and iodide atom in perfluoroalkyl substances.

Integration of vacuum UV/peroxydisulfate and reductive processes for the thorough defluorination of 8:3 fluorotelomer carboxylates: The critical contribution of preoxidation

Fluorotelomers have been systematically developed in bulk quantities and extensively applied in the fluoropolymer industry. Reductive treatments of fluorotelomers are different from those of perfluoroalkyl substances. In this study, vacuum UV/peroxydisulfate (VUV/PDS) was used for the first time to preoxidize 8:3 fluorotelomer carboxylates (8:3FTCA). Subsequently, it was integrated with the VUV/sulfite/iodide reductive process to accomplish the comprehensive defluorination of the oxidized products. The performance and mechanisms of 8:3FTCA degradation in the preoxidation process were mainly explored. pH values from 6.0 to 8.0 were conducive to 8:3FTCA decomposition. Hydrogen peroxide, hydroxyl radical (•OH), and hydroperoxyl radical (HO2•) were observed to be in a dynamic equilibrium state of mutual transformation, and the contributions of •OH and HO2• were 76.8 % and 17.4 %, respectively. The investigation of the influences of background water matrices demonstrated minimal adverse effects of sulfate and chloride, whereas bicarbonate, carbonate, and natural organic matter exhibited inhibitory effects. The degradation pathways of 8:3FTCA were speculated through density functional theory calculation and intermediate identification. The Ecological Structure–Activity Relationships simulation showed that VUV/PDS preoxidation decreased the aquatic toxicity of 8:3FTCA. These findings provide valuable insights for addressing challenges associated with fluorotelomer carboxylates.

Association of perfluoroalkyl substances (PFAS) with liver function biomarkers in the highly exposed population of the veneto region

IntroductionEpidemiological studies highlight the presence of associations between per- and polyfluoroalkyl substances (PFAS) exposure with liver damage. In 2013, PFAS contamination was discovered in Veneto (Italy), leading to the implementation of a Surveillance Program (SP). Our objective is to investigate the association between PFAS exposure and biomarkers of liver function using single-pollutant and mixture approaches, while exploring the sex-specific differences and the mediating role of obesity in the association. MethodsThe study included 42,094 subjects aged ≥20 years participating in the SP. We used generalized additive models to investigate the association between several PFAS and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, adjusting for possible confounders and stratifying by sex. Results were back-transformed to show predicted percentage changes in outcomes per ln-unit increase in PFAS levels; furthermore, we explored the role of BMI in the abovementioned causal pathway, considering it as a potential confounder or mediator PFAS joint effect was investigated using Quantile G-computation. ResultsOne ln-unit increase in PFHxS concentrations was associated with a 1.49% (95%CI: 0.87, 2.12) and a 0.84% (95% CI: 0.27, 1.40) increase in ALT levels, in males and females respectively; one ln-unit increase in PFOA concentrations was associated with a 1.03% (95%CI: 0.50, 1.55) increase in ALT levels in males, and a 0.52% (95% CI: 0.22, 0.82) and a 0.60% (95% CI: 0.25, 0.96) increase in AST levels in females and males. PFOS showed no association with ALT and AST levels. Quantile G-computation revealed that an interquartile increase in the PFAS mixture was associated with a 3.02% increase (95% CI: 1.65, 4.43) and a 1.65% (95% CI: 0.77, 2.5) increase in ALT levels, in females and males. Mediation analysis suggested that BMI suppressed the association between PFAS and ALT levels, with positive direct effects higher than the total effects. ConclusionOur findings suggest sex-specific associations between PFAS exposure and liver function biomarkers and underscore the need for additional studies on potential mediators.