Perfluoroalkyl Substances Research Articles

Effluents from septic systems and impact on groundwater contamination: a systematic review.

Globally, 2.2 billion people rely on groundwater for their water supply, and 2.8 billion use onsite sanitation systems for their sanitation needs. Groundwater contamination from septic systems is a critical public health concern, linked with diseases related to water sanitation and hygiene. Despite the severe impacts of septic systems on groundwater quality, comprehensive global studies remain limited. This study conducted a systematic review of articles published between 2012 and 2023 on topics related to septic systems and groundwater contamination, and 82 peer-reviewed articles met the inclusion criteria. The review identified key contaminants, including E.coli, nitrate, Enterococcus spp., total coliform, ammonium, phosphate, chlorides, and pharmaceuticals. Research on microbial indicators is more prevalent in Africa, while research on nutrients is common in North America. Research on organic contaminants including polyfluoroalkyl substances (PFAS), pharmaceuticals, and personal care products (PCPPs) is limited, particularly in low-and middle-income countries. Critical factors contributing to groundwater contamination include soil, hydrogeological conditions, climate, septic system maintenance and functioning, and septic density. The goal of this study was to comprehensively assess the extent of groundwater contamination resulting from septic system effluents by identifying the major contaminants typically found in affected groundwater sources and exploring the factors contributing to contamination. Identifying the major contaminants and factors related to groundwater contamination from septic systems is crucial for developing effective management strategies to protect groundwater sources.

Legacy and Novel Per- and Polyfluoroalkyl Substances in Surface Soils across China: Source Tracking and Main Drivers for the Spatial Variation.

China aims to actively control the contamination of globally concerning per- and polyfluoroalkyl substances (PFASs). Evaluation of the current situation can provide a critical reference point for tracking the effectiveness of ongoing progress. Herein, we present the first comprehensive assessment of the spatial variations of 20 legacy and 54 novel PFASs in Chinese background soils in 2021. Novel PFASs were extensively detected in 98.4% of the samples, with 21 species being first reported, which greatly facilitated the appointment of diverse emission sources that aligned with local industrial structures. However, legacy PFASs still dominated the ∑74PFAS profile (median 0.51 ng/g, 0.050-8.33 ng/g). The spatial heterogeneity of soil PFASs was positively driven by economic development and atmospheric deposition, enabling the establishment of predictive models to project the national distribution and temporal trends. Elevated PFAS levels were predominantly distributed in the more industrialized eastern and southern regions, as well as other coastal areas with greater precipitation. ∑74PFAS in surface soils was estimated to increase by 12.9 pg/(g year) over 2002-2021, which would continue alongside economic growth, albeit with greater contributions from novel alternatives. Our work provides comprehensive baseline and predictive data to inform policies toward PFAS control in China.

The trends of per-and polyfluoroalkyl substances (pfas) in drinking water systems in Maryland United States

Per- and polyfluoroalkyl substances (PFAS) have become a major concern in water quality management because of their persistence in the environment and associated health risks. In Maryland, the diverse water resources and densely populated areas, faces unique challenges culminating from PFAS contamination. This research paper presents a comprehensive overview of PFAS contamination trends in Maryland's drinking water systems across four distinct phases, spanning from 2019 to 2022, it highlights the trends of PFAS contamination, environmental and public health risks, and strategies for effective management. Utilizing data from extensive monitoring efforts conducted in the state, the study reveals a persistent and evolving environmental health challenge characterized by the dominance of different PFAS compounds, particularly PFOS and PFOA, found at concerning concentrations. Mean concentrations of total PFOA/PFOS across the sampling periods were at 18.78 ng/L, 7.28 ng/L, 14.60 ng/L, 12.46 ng/L, significantly surpassing the EPA's 2024 maximum contaminant levels of 4 ng/L for PFOA and PFOS. Despite fluctuations observed across sampling phases, PFAS levels consistently surpass EPA health advisory levels, indicating widespread contamination. Potential sources, such as industrial sites and wastewater treatment plants, underscore the need for robust regulatory enforcement and innovative remediation strategies to safeguard public health. The findings emphasize the necessity for continuous monitoring and multi-faceted mitigation approaches to address PFAS contamination effectively, ensuring the safety of Maryland's water resources and the health of its residents.

The Global Threat from the Irreversible Accumulation of Trifluoroacetic Acid (TFA).

Trifluoroacetic acid (TFA) is a persistent and mobile substance that has been increasing in concentration within diverse environmental media, including rain, soils, human serum, plants, plant-based foods, and drinking water. Currently, TFA concentrations are orders of magnitude higher than those of other per- and polyfluoroalkyl substances (PFAS). This accumulation is due to many PFAS having TFA as a transformation product, including several fluorinated gases (F-gases), pesticides, pharmaceuticals, and industrial chemicals, in addition to direct release of industrially produced TFA. Due to TFA's extreme persistence and ongoing emissions, concentrations are increasing irreversibly. What remains less clear are the thresholds where irreversible effects on local or global scales occur. There are indications from mammalian toxicity studies that TFA is toxic to reproduction and that it exhibits liver toxicity. Ecotoxicity data are scarce, with most data being for aquatic systems; fewer data are available for terrestrial plants, where TFA bioaccumulates most readily. Collectively, these trends imply that TFA meets the criteria of a planetary boundary threat for novel entities because of increasing planetary-scale exposure, where potential irreversible disruptive impacts on vital earth system processes could occur. The rational response to this is to instigate binding actions to reduce the emissions of TFA and its many precursors.

Large scale study on PFASs levels in fruits, vegetables and soil from allotments and gardens contaminated by atmospheric deposition from a Dutch fluorochemical production plant

Citizens grow their own fruits and vegetables in allotment gardens in the vicinity of a fluorochemical production plant (FCPP) in The Netherlands. Historic emissions and the subsequent atmospheric deposition of perfluorooctanoic acid (PFOA) and GenX (hexafluoropropylene oxide-dimer acid / HFPO-DA) from the FCPP have resulted in the nearby environment being contaminated with per- and polyfluoroalkyl substances (PFASs). This research aimed to investigate the levels of PFASs in garden produce and whether a gradient can be observed in relation to distance from the FCPP. Furthermore, differences between certain types of fruits and vegetables were explored, as well as a potential relation between the measured concentrations in garden produce and soil. 737 fruit and vegetable samples were collected from 17 allotments and 4 gardens up to 20 kilometres from the FCPP, along with soil and water samples. Garden produce included fruits, potatoes, fruiting vegetables, brassicas, leafy vegetables, root vegetables, bulb vegetables, legumes and stem vegetables. PFASs concentrations in the samples were quantified using a very sensitive UPLC-MS/MS method. PFASs were detected in most samples above the analytical limit of detection (0.3 to 12.5 pg/g ww). PFOA and GenX were found in the highest concentrations (up to 5280 pg/g ww GenX and 3020 pg/g ww PFOA) in garden produce sampled downwind and close to the FCPP. Other PFASs were also found, but at (much) lower levels. Field-derived bioaccumulation factors (BAFs) were calculated for PFOA and GenX. The BAFs for PFOA were shown to be approximately 1 order of magnitude lower than BAFs from other studies. This may be explained by aging of the PFASs contamination and the intense cultivation of the garden plots. This study shows that PFOA and GenX can end up in garden produce and this will result in human exposure when the garden produce is consumed.

Aptamer-Triggered Nucleic Acid Amplification Strategy for the Electrochemiluminescence Detection of Perfluorooctanoic Acid.

Per- and polyfluoroalkyl substances (PFASs) are a class of persistent micropollutants. Due to their chemical stability and bioaccumulation, concentrations of PFASs in environmental media, even at ultratrace levels, pose significant environmental and health risks. However, currently reported detection methods lack an effective signal amplification strategy, and the detection sensitivity is limited, which can not meet the requirements of ultratrace detection. Herein, a groundbreaking aptamer-recognition-driven nucleic acid strategy was developed to significantly amplify the detection signal of perfluorooctanoic acid (PFOA). Furthermore, step pulse (SP) was used instead of cyclic voltammetry (CV) as an electrochemical excitation method to modulate the low electrochemiluminescence (ECL) triggering potential of poly [9,9-bis (3'-(N, N-dimethylamino) propyl) -2,7-fluorene]-alt-2,7-(9,9-dioctylfluorene)] (PFN) nanoparticles (NPs) so that a strong signal of +0.80 V was emitted without any exogenous coreactants. PFN NPs coupled rolling circle amplification-assisted PAM-free CRISPR/Cas12a system to construct an ultrasensitive ECL aptasensor for PFOA detection and the limit of detection was as low as 1.97 × 10-15 M. This ECL system integrated the advantages of no exogenous coreactants, low trigger potential, and nucleic acid amplification strategy and provided an ultrasensitive method for monitoring trace PFOA in the real water sample.

Forever Chemicals, Endless Testing? Expert Advice to Be Prepared for Per- and Polyfluoroalkyl Substances.

Forever Chemicals, Endless Testing? Expert Advice to Be Prepared for Per- and Polyfluoroalkyl Substances.

Non-target screening reveals 124 PFAS at an AFFF-impacted field site in Germany specified by novel systematic terminology.

The uncontrolled release of aqueous film-forming foam (AFFF) ingredients during a major fire incident in Reilingen, Germany, in 2008 led to significant soil and groundwater contamination. As the identity of fluorochemical surfactants in AFFF are often veiled due to company secrets, it is important to characterize AFFF contaminations and their impact on the environment comprehensively. In this study, we adapted a systematic approach combining a suitable extraction method with liquid chromatography high-resolution quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for an extensive non-targeted analysis. Our analysis identified 124 per- and polyfluoroalkyl substances (PFAS) from 42 subclasses in the contaminated soil (confidence levels of identification between 1 and 3). Typical for AFFF-impacted field sites, these included anionic, cationic, and zwitterionic substances with perfluoroalkyl chains spanning from 3 to 14 carbon atoms. Furthermore, we identified 1 previously unreported substance, and detected 9 PFAS subclasses for the first time in soil. AFFFs have long been employed to extinguish large hydrocarbon fires, yet their environmental consequences remain a concern. This study sheds light on the complex composition of AFFFs at this particularly contaminated area, emphasizing the necessity for extensive contaminant characterization as sound basis for informed management strategies to mitigate their adverse effects. AFFF PFAS are often named differently in the literature, leading to inconsistency in terminology. To address this issue, we introduced partially new terminology for AFFF-related PFAS to establish consistent terminology, to facilitate communication of identified compounds, and to ensure that the chemical structure can be directly derived from acronyms.

Destruction of Per- and Polyfluoroalkyl Substances in Reverse Osmosis Concentrate Using UV-Advanced Reduction Processes.

UV-advanced reduction processes (UV-ARP), characterized by the strongly reducing aqueous electron (eaq -), have been shown to degrade perfluoroalkyl and polyfluoroalkyl substances (PFAS). Due to the high cost of PFAS destruction technologies, concentrated waste streams derived from physical treatment processes, such as ion exchange or membrane concentrates, are promising targets for implementation of these technologies. However, there are limited studies on the application of UV-ARP for PFAS destruction in concentrated waste streams. This study evaluates the effectiveness of the UV/sulfite ARP in reverse osmosis concentrate (ROC) containing high concentrations of dissolved organic carbon (DOC), nitrate, and carbonate species, spiked with mg/L concentrations of perfluorooctanesulfonic acid, perfluorobutanesulfonic acid, perfluorooctanoic acid, and perfluorobutanoic acid. We demonstrate that hardness removal and preoxidation of ROC with UV/persulfate enables >90% PFAS defluorination within 24 h of subsequent UV/sulfite treatment, a 3-fold enhancement in defluorination % compared to UV/sulfite treatment without preoxidation. This enhancement is shown to result from abatement of the light shielding and eaq - scavenging capacity of DOC during UV/persulfate oxidation. Collectively, these results demonstrate that appropriate pretreatment steps increase the effectiveness of PFAS destruction using UV-ARP, supporting the application of UV-ARP for PFAS destruction in ROC and other concentrated waste streams.

A comprehensive review of emerging contaminants in water sources

The quality of water is crucial for the health of both the environment and humans, but new challenges from emerging contaminants threaten this vital resource. This paper reviews the origin and significance of water quality issues linked to emerging pollutants, including pharmaceuticals, personal care products, endocrine-disrupting chemicals, per- and polyfluoroalkyl substances, microplastics, pesticides, and industrial chemicals. These persistent chemicals exhibit complex behaviors and have the potential to impact ecological systems and human health significantly. The review comprehensively examines the pathways through which these pollutants enter water systems, such as agricultural runoff, industrial discharges, and urban stormwater runoff. It also covers the latest techniques for identifying these pollutants, emphasizing recent advancements in sampling methods and analytical techniques while highlighting the challenges of detecting contaminants at low concentrations. The discussion includes the environmental behavior of these contaminants, focusing on their properties, degradation mechanisms, and bioaccumulation potential. It further explores the impacts of these emerging contaminants on ecosystems and human health, examining both conventional and innovative treatment technologies. Additionally, the review identifies current research gaps and future trends in the analysis of new pollutants. It underscores the importance of public awareness, effective communication strategies, and innovative approaches to environmental protection.

Occurrence and efficient removal of PFAS from landfill leachates using on-site DTRO systems: A comprehensive analysis across 11 Chinese cities

Per- and polyfluoroalkyl substances (PFAS), known for their persistent toxicity and mobility, pose significant environmental and human health risks. Here we explored the occurrence and efficacy of on-site Double-Pass Reverse Osmosis (DTRO) systems in removing 30 different PFAS from landfill leachates in 11 diverse cities across China. PFAS concentrations in landfill leachate ranged from 938 to 32,491 ng/L, averaging 6,486 ng/L, predominantly comprising short-chain PFAS, notably perfluorobutane sulfonate (PFBS). Notable emerging substitutes like 6:2 fluorotelomer sulfonate, fluorobutane sulfonamide, and 9-chlorohexadecafluoro-3-oxanone sulfonate were also identified. The PFAS levels correlated positively (r2 = 0.79, p < 0.01) with regional economic development, with coastal areas exhibiting higher concentrations than inland regions. The DTRO membrane filtration and ion exchange resin achieved an average removal efficiency of 94 % for ∑30PFAS and even 99.97 % for PFBS (the concentration of PFBS in the raw leachate ranged from 226.36 ng/L to 27,935.61 ng/L, with an average concentration of 4,506.88 ng/L). The Na ion exchange resin had a limited effect on further reducing the PFAS concentration. Our findings not only contribute to the theoretical understanding of PFAS behavior in landfill leachates but also offer a practical engineering applications for global waste management practices.

Field versus laboratory measurements of PFAS sorption by soils and sediments

Sorption by soils and sediments is an important process that influences the distribution, transport, and fate of per and polyfluoroalkyl substances (PFAS) in the environment. Many laboratory studies have been conducted to quantify magnitudes of PFAS sorption as a function of the properties of the PFAS, solutions, and porous media. A critical question is how representative are laboratory-measured sorption magnitudes for field applications. To address this question, log Koc data were compiled from the literature for a range of PFAS of different chain lengths and functional groups. The aggregated field-based data consisted of two types, in-situ measurements comprising paired soil/sediment and water samples and ex-situ measurements obtained from laboratory desorption experiments employing field-contaminated media. These two sets of field-based measurements were compared to a comprehensive data set of standard laboratory batch-type measurements. The compiled data sets represent an extremely wide range of soil and sediment properties. One important novel outcome is the observation that the enhanced sorption of short-chain PFAS observed in several prior laboratory studies is also observed for the field data. This differential enhanced sorption should be accounted for in site investigations and modeling studies. Another relevant outcome is the observation of consistency between measurements obtained with standard batch adsorption experiments and those from desorption studies employing either field-contaminated or artificially-contaminated media. The mean log Koc values determined for the in-situ measured field data were generally larger than the mean laboratory-determined values, particularly for the short-chain PFAS. Notably, however, values for subsets of the laboratory data representing measurements for lower aqueous concentrations or for soils with low organic-carbon contents (<1 %) compared well to the in-situ field data. Measurements compiled for anionic-polyfluoroalkyl, neutral, and cationic PFAS compared well to those for PFCAs and PFSAs. Overall, the results indicate that the laboratory measurements of PFAS sorption were generally representative of the field-derived magnitudes when compared on a consistent basis.

Efficient Online TurboFlow Method for Simultaneous Determination of 60 Emerging Per- and Polyfluoroalkyl Substances in Milk.

Emerging perfluoroalkyl and polyfluoroalkyl substances (PFASs) have received much attention in recent years. Milk has usually low concentrations of PFASs, but it remains an important PFAS exposure route due to its high consumption. In this study, a method for simultaneous determination of 60 PFASs in milk was developed by online TurboFlow liquid chromatography-tandem mass spectrometry. A pH-dependent cold-induced liquid-liquid extraction was developed for precleanup and enrichment. Method quantification limits ranged from 0.003 to 0.500 ng/mL. For PFASs without corresponding isotope-labeled internal standards, Tanimoto coefficient and logP were introduced for the selection of internal standards. The matrix spiked recoveries ranged from 47 to 190%. The method was applied for PFAS analysis in 35 milk samples. PFBS, perfluorohexanesulfonic acid, perfluorooctanesulfonic acid, PFNS, PFPeA, perfluorooctanoic acid, PFNA, and 6:2 FTS were detected. The developed online TurboFlow method was simple, reliable, efficient, and applicable for trace analysis of PFASs in milk.

Predictions of groundwater PFAS occurrence at drinking water supply depths in the United States.

Per- and polyfluoroalkyl substances (PFAS), known colloquially as "forever chemicals", have been associated with adverse human health effects and have contaminated drinking water supplies across the United States owing to their long-term and widespread use. People in the United States may unknowingly be drinking water that contains PFAS because of a lack of systematic analysis, particularly in domestic water supplies. We present an extreme gradient boosting model for predicting the occurrence of PFAS in groundwater at the depths of drinking water supply for the conterminous United States. Our model results indicate that 71 to 95 million people in the conterminous United States potentially rely on groundwater with detectable concentrations of PFAS for their drinking-water supplies prior to any treatment.

Associations between gestational exposure to perfluoroalkyl substances, fetal growth, and the mediation effect of thyroid hormones

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) may cause adverse birth outcomes. Thyroid hormones may play a key role in mediating the effects of PFAS. We enrolled 374 mother-infant pairs from the Ezhou birth cohort study between 2019 and 2020. Eight PFASs and six thyroid hormones were measured in maternal serum during the first trimester of pregnancy. Neonatal growth metrics, including birth weight, length, head circumference, and gestational age, were acquired. Multivariate linear regression was performed to determine the associations between maternal serum PFAS and thyroid hormone levels and birth outcomes and a mediation analysis was also conducted. Except for perfluoroheptanoic acid (41.2%), the other seven PFAS detection rates were more than 85%, and the highest median concentration was observed for PFOSA with levels of 5.21 ng/mL. After controlling for typical confounders, we observed a decrease in birth length (cm) with increasing serum concentrations of perfluorononanoic acid (PFNA) (β = -0.54; 95% CI = -1.0, -0.08) and perfluorohexane sulfonate (PFHxS) (β = -0.64; 95% CI = -0.86, -0.42). Additionally, a decrease in birth head circumference was observed with increasing concentrations of perfluorooctanote (PFOA) (β = -0.73, 95% CI = -1.19, -0.27) and PFHxS (β = -0.30; 95% CI = -0.53, -0.07). Maternal free triiodothyronine (FT3) mediated 36.7% of the negative association between PFNA and birth length, and free thyroxine (FT4) mediated 30.8% of the effect of PFOA on head circumference. When performing stratified analysis by infant sex, the associations might differ between boys and girls. Our study suggested prenatal exposure to some PFASs was negatively associated with birth length and circumference, and FT3 and FT4 may partly mediate the association.

Perfluorobutanoic acid weakens the heterogeneous aggregation of microplastics and microalgae: Perspective from physicochemical properties, extracellular polymeric substances secretion and DLVO theory

Microplastics (MPs) and per- and poly-fluoroalkyl substances extensively coexist in aquatic environments and potentially endanger organisms. Microalgae may decrease the effective concentration of pollutants via hetero-aggregation with MPs and adsorption of emerging contaminants. However, the potential influence of coexistent pollutants on hetero-aggregation of MPs and microalgae remains unknown. This study investigated the hetero-aggregation process involving different sizes of polystyrene (PS, 3.0 and 50.0 μm) with Chlorella sorokiniana (C. sorokiniana) in the presence or absence of perfluorobutanoic acid (PFBA) along settling experiments, scanning electron microscope, and Derjaguin-Landau-Verwey-Overbeek (DLVO) model. We found that the hetero-aggregation between C. sorokiniana and 3 μm PS was more pronounced than with 50 μm PS, while PFBA inhibited this process. ΔOD1 values (reflected hetero-aggregation level) for 3PS-cells and 50PS-cells were 0.189 and 0.087, respectively, and PFBA decreased these values to 0.134 and 0.033. Furthermore, extracellular polymeric substances, known as inducer of hetero-aggregation, increased by 14.33% when exposed to 3 μm PS alone, whereas the co-exposure group showed a decrease of 4.52% compared to 3PS-cells group. PFBA also significantly decreased the protein/polysaccharide ratios in both MPs sizes, reducing hetero-aggregation. DLVO theory revealed that microalgae lowered the energy barrier significantly, while PFBA elevated it, indicating that hetero-aggregation was inhibited by PFBA. This study provides new perspectives for pollutant removal and toxicity variation in aquatic environments.

Statistical Mapping of PFOA and PFOS in Groundwater throughout the Contiguous United States.

Per-and polyfluoroalkyl substances (PFAS) are synthetic chemicals that are increasingly being detected in groundwater. The negative health consequences associated with human exposure to PFAS make it essential to quantify the distribution of PFAS in groundwater systems. Mapping PFAS distributions is particularly challenging because a national patchwork of testing and reporting requirements has resulted in sparse and spatially biased data. In this analysis, an inhomogeneous Poisson process (IPP) modeling approach is adopted from ecological statistics to continuously map PFAS distributions in groundwater across the contiguous United States. The model is trained on a unique data set of 8910 PFAS groundwater measurements, using combined concentrations of two PFAS analytes. The IPP model predictions are compared with results from random forest models to highlight the robustness of this statistical modeling approach on sparse data sets. This analysis provides a new approach to not only map PFAS contamination in groundwater but also prioritize future sampling efforts.

Ab Initio Investigation of Per- and Poly-fluoroalkyl Substance (PFAS) Adsorption on Zerovalent Iron (Fe0).

In this study, dispersion-corrected density functional theory (DFT) calculations were employed to investigate the adsorption of per- and poly-fluoroalkyl substances (PFAS) onto zerovalent iron (Fe0). The main objective of this investigation was to shed light on the adsorption properties, including adsorption energies, geometries, and charge transfer mechanisms, for four PFAS molecules, namely, perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorobutanoic acid (PFBA), on the most thermodynamically accessible Fe0 surface facets. Additionally, the DFT investigation examined the role of PFAS chain length, functional group, protonation/deprotonation state, and solvation in water in their adsorption to Fe0. Overall, the adsorption of the four PFAS molecules on various Fe0 surfaces exhibited thermodynamically favorable energetics. Nevertheless, solvation in water resulted in less exothermic adsorption energies, and the presence of preadsorbed oxygen blocked the Fe0 surface, preventing PFAS adsorption. Additionally, the inclusion of a monolayer of Ni on top of the Fe0 surface reduced the stability of PFAS adsorption compared to pristine Fe0. Results of the computational investigation were compared to experimental results from the literature for qualitative validation.

Side-Reactions of Polyvinylidene Fluoride and Polyvinylidene Chloride Binders with Aluminum Chloride-Based Ionic Liquid Electrolyte in Rechargeable Aluminum-Batteries

Abstract Rechargeable aluminum batteries (RABs) use a Lewis acidic aluminum chloride (AlCl3) and 1-Ethyl-3-methylimidazolium chloride (EMImCl) ionic liquid electrolyte. Electrode fabrication often relies on procedures from lithium-ion batteries (LIBs), including the use of Polyvinylidene fluoride (PVdF) as a binder. However, PVdF reacts with Al2Cl7- in the RAB electrolyte, making it unsuitable for new battery types. The literature lacks details on the products formed, changes in the ionic liquid electrolyte, and the implications for electrochemical performance. With potential European Chemical Agency restrictions on per- and polyfluoroalkyl substances (PFAS) by 2025, Polyvinylidene chloride (PVdC) is being explored as an alternative binder. In contact with AlCl3:EMImCl (1.50:1.00) electrolyte, both, PVdF and PVdC transform into amorphous carbon during dehydrofluorination and dehydrochlorination, respectively, as confirmed by Raman spectroscopy. Furthermore, via 19F-NMR, it is shown that the reaction time between the soaked polymers and the ionic liquid has a significant influence on the newly formed aluminum chlorofluoride complexes. Electrochemical tests of graphite-based electrodes indicate increasing specific capacity of PVdF compared to PVdC with a continuous number of cycles. Amorphous carbon can prevent the disintegration of graphite and enhance conductivity. Furthermore, newly formed AlF4- can run a co-intercalation and lead to increasing specific capacity.

Incorporating ultrashort-chain compounds into the comprehensive analysis of per- and polyfluorinated substances in potable and non-potable waters by LC-MS/MS

Ultrashort-chain (USC) per- and polyfluoroalkyl substances (PFAS) are small and very polar compounds with carbon chain lengths shorter than C4. Their ubiquitous and high levels of occurrence in environmental aquatic systems are emerging as a significant concern, rivaling the well-established issues associated with long-chain PFAS contamination. Therefore, it is important to analyze both USC and long-chain PFAS together in water samples to comprehensively assess and address the full spectrum of PFAS contamination. The high polarity of USC PFAS poses a challenge for standard chromatographic practices in PFAS analysis, primarily due to insufficient chromatographic retention. In this study, a simple and reliable workflow was developed for the simultaneous analysis of C1 to C14 perfluoroalkyl carboxylic and sulfonic acids, along with other groups of PFAS, in both potable and non-potable waters. The chromatographic separation was conducted using a polar-embedded reversed-phase LC column with an inert coating on the hardware. Three different water matrices (tap water, bottled water, sewage treatment wastewater) were chosen for method evaluation to demonstrate the applicability of the developed workflow for measuring 45 PFAS compounds in diverse water samples. A dilute-and-shoot workflow was evaluated by accuracy and precision analysis at five fortification levels, ranging from 2 to 250 ng/L. Eighteen isotopically labeled PFAS, serving as extracted internal standards, were added to the samples at 100 ng/L to validate the accuracy of the entire workflow. Calibration standards were prepared in reverse osmosis water due to its cleanliness for all analytes. The calibration ranges varied among different analytes, spanning from 1 – 1000 ng/L. All analytes and extracted internal standards exhibited recovery values ranging from 70% to 130% of the nominal concentration across all fortification levels. Satisfactory method precision was demonstrated with %RSD values below 20%. Additional potable and non-potable waters collected from various source waters were tested to further demonstrate that the established workflow is suitable for the accurate quantification of targeted PFAS in a wide range of water matrices.