Occurrence of different classes of perfluorinated compounds in Greek wastewater treatment plants and determination of their solid-water distribution coefficients

Exploring the variability of PFAS in urban sewage: a comparison of emissions in commercial versus municipal urban areas

Per- and polyfluoroalkyl substances (PFAS) are recognized for their persistence and ubiquitous occurrence in different environmental compartments. Conventional wastewater treatment plants (WWTPs) cannot effectively remove PFAS from wastewater, and a better understanding of the occurrence and sources of PFAS in this medium would enable effective source abatement. We compared sewage from urban areas exhibiting differentiating characteristics with respect to activities in their catchments. These included a sewer that serves primarily a municipal area, with no commercial activities involving PFAS emissions being identified, another sewer with a strong influence of commercial activities potentially related to PFAS emissions, and the influent of the whole city sewage network. The year-long monitoring campaign consisted of flow-proportional, monthly composite samples and targeted analysis of 29 PFAS compounds. Principal component analysis was used to investigate the relationships between selected PFAS and standard water quality parameters such as ammonium, a known tracer of urine and thus of typical municipal wastewater. Notable findings were seen for PFOS and 6:2 FTS, whose concentrations were most negatively correlated with ammonium. Ammonium concentration data allowed for a normalized per-person median load calculation, which resulted in loads of the observed PFAS ranging from below 0.4 up to 4.7 μg per person per day. Both the commercial area sewer and the city influent exhibited significantly higher (p < 0.05) median loads (>0.9 μg per person per day) in the case of 6:2 FTS and PFOS, compared to the municipal sewer (<0.6 μg per person per day). No statistically significant difference was found for other compounds, such as PFBA, PFHxA, PFOA, and PFHxS. We argue that this approach demonstrates that PFAS can differ in speciation and quantity within an urban wastewater setting, and consideration of both municipal and commercial activities is needed for a proper understanding of sources and emission pathways within the urban environment.

Microplastics and per- and polyfluoroalkyl substances (PFAS) in landfill-wastewater treatment systems: A field study

Landfills and wastewater treatment plants (WWTP) are point sources for many emerging contaminants, including microplastics and per- and polyfluoroalkyl substances (PFAS). Previous studies have estimated the abundance and transport of microplastics and PFAS separately in landfills and WWTPs. In addition, previous studies typically report concentrations of microplastics as particle count/L or count/g sediment, which do not provide the information needed to calculate mass balances. We measured microplastics and PFAS in four landfill-WWTP systems in Illinois, USA, and quantified mass of both contaminants in landfill leachate, WWTP influent, effluent, and biosolids. Microplastic concentrations in WWTP influent were similar in magnitude to landfill leachates, in the order of 102 μg plastic/L (parts-per-billion). In contrast, PFAS concentrations were higher in leachates (parts-per-billion range) than WWTP influent (parts-per-trillion range). After treatment, both contaminants had lower concentrations in WWTP effluent, although were abundant in biosolids. We concluded that WWTPs reduce PFAS and microplastics, lowering concentrations in the effluent that is discharged to nearby surface waters. However, partitioning of both contaminants to biosolids may reintroduce them as pollutants when biosolids are landfilled or used as fertilizer.

Biochar from Co-Pyrolyzed Municipal Sewage Sludge (MSS): Part 1: Evaluating Types of Co-Substrates and Co-Pyrolysis Conditions

With the increasing production of municipal sewage sludge (MSS) worldwide, the development of efficient and sustainable strategies for its management is crucial. Pyrolysis of MSS offers several benefits, including volume reduction, pathogen elimination, and energy recovery through the production of biochar, syngas, and bio-oil. However, the process can be limited by the composition of the MSS, which can affect the quality of the biochar. Co-pyrolysis has emerged as a promising solution for the sustainable management of MSS, reducing the toxicity of biochar and improving its physical and chemical properties to expand its potential applications. This review discusses the status of MSS as a feedstock for biochar production. It describes the types and properties of various co-substrates grouped according to European biochar certification requirements, including those from forestry and wood processing, agriculture, food processing residues, recycling, anaerobic digestion, and other sources. In addition, the review addresses the optimization of co-pyrolysis conditions, including the type of furnace, mixing ratio of MSS and co-substrate, co-pyrolysis temperature, residence time, heating rate, type of inert gas, and flow rate. This overview shows the potential of different biomass types for the upgrading of MSS biochar and provides a basis for research into new co-substrates. This approach not only mitigates the environmental impact of MSS but also contributes to the wider goal of achieving a circular economy in MSS management.

Can on-site leachate treatment facilities effectively address the issue of perfluoroalkyl acids (PFAAs) in leachate?

In recent decades, the presence of perfluoroalkyl acids (PFAAs) in municipal solid waste leachate has emerged as a growing concern. Research has focused on PFAA release and occurrence characteristics in landfill and waste-to-energy leachate, highlighting their significant impact when released into wastewater treatment plants. Given the extremely high loading rate faced by current on-site leachate treatment plants (LTPs), the objective of this study is to assess whether the current "anaerobic/aerobic (A/O) + membrane bioreactor (MBR) + nanofiltration (NF) + reverse osmosis (RO)" configuration is effective in PFAAs removal. Concentrations of raw and treated leachate in 10 on-site LTPs with same treatment configuration and varying landfill ages were measured, and a comprehensive mass flow analysis of each treatment process was conducted. The results indicate that A/O treatment has limited capacity for PFAA removal, while NF and RO processes reached 77.44 % and 94.30 % removal rates of ∑PFAAs concentration, respectively. Short-chain PFAAs (> 80 % detected frequency) primarily influenced the distribution and variations of PFAAs in leachate and tend to disperse in the water phase. Correlation analysis revealed the current on-site LTPs exhibit a more efficient removal capacity for long-chain PFAAs.

Analysis of perfluorinated compounds in sewage sludge and hydrochar by UHPLC LTQ/Orbitrap MS and removal assessment during hydrothermal carbonization treatment

Wastewater treatment plants have been recognized as important sinks for per- and polyfluoroalkyl substances (PFAS) because of their ineffectiveness in removing them reflecting both water and sewage sludge discharge routes. Hydrothermal treatment represents an alternative technology for treating sludge to recover energy and other valuable products. In this study, 15 PFAS were determined in sludge and hydrochar substrates using sonication-solid phase extraction procedure and analyzed using LC-Orbitrap-High Resolution-MS/MS. The method was fully validated, exhibiting very good linearity, recoveries in the range of 48 to 126 %, low detection and quantification limits with expanded uncertainty and precision below 32 % and 21.9 %, respectively. The method was applied to sludge samples from the WWTP of Ioannina city (Greece), as well as to hydrothermally treated samples under various conditions. The most abundant PFAS were PFHxA (0.5-38.3 ng g-1) and PFOS (4.4-22.1 ng g-1). Finally, the hydrothermally treated sludge samples spiked with PFAS presented removal efficiencies for total PFAS of 86.9 %, 91.8 % and 95.7 % at three spiking levels namely 10, 50 and 200 ng g-1, respectively. Results indicated that PFCAs were almost completely removed, except for PFOA, while the concentrations of PFSAs increased in the produced hydrochar with the formation of several intermediates, as detected by HR-LC-MS/MS. The results of this study demonstrate the effect of hydrothermal treatment to the fate of PFAS in sewage sludge and contribute for further studies on design and scale up of hydrothermal carbonization technology as a management option for safer disposal of municipal wastewater sludge.

Eco-toxicological and climate change effects of sludge thermal treatments: Pathways towards zero pollution and negative emissions

The high moisture content and the potential presence of hazardous organic compounds (HOCs) and metals (HMs) in sewage sludge (SS) pose technical and regulatory challenges for its circular economy valorisation. Thermal treatments are expected to reduce the volume of SS while producing energy and eliminating HOCs. In this study, we integrate quantitative analysis of SS concentration of 12 HMs and 61 HOCs, including organophosphate flame retardants (OPFRs) and per- and poly-fluoroalkyl substances (PFAS), with life-cycle assessment to estimate removal efficiency of pollutants, climate change mitigation benefits and toxicological effects of existing and alternative SS treatments (involving pyrolysis, incineration, and/or anaerobic digestion). Conventional SS treatment leaves between 24 % and 40 % of OPFRs unabated, while almost no degradation occurs for PFAS. Thermal treatments can degrade more than 93% of target OPFRs and 95 % of target PFAS (with the rest released to effluents). The different treatments affect how HMs are emitted across environmental compartments. Conventional treatments also show higher climate change impacts than thermal treatments. Overall, thermal treatments can effectively reduce the HOCs emitted to the environment while delivering negative emissions (from about -56 to -111 kg CO2-eq per tonne of sludge, when pyrolysis is involved) and producing renewable energy from heat integration and valorization.

Biosolids, an important route for transporting poly- and perfluoroalkyl substances from wastewater treatment plants into the environment: A systematic review

The pervasive presence of poly- and perfluoroalkyl substances (PFAS) in diverse products has led to their introduction into wastewater systems, making wastewater treatment plants (WWTPs) significant PFAS contributors to the environment. Despite WWTPs' efforts to mitigate PFAS impact through physicochemical and biological means, concerns persist regarding PFAS retention in generated biosolids. While numerous review studies have explored the fate of these compounds within WWTPs, no study has critically reviewed their presence, transformation mechanisms, and partitioning within the sludge. Therefore, the current study has been specifically designed to investigate these aspects. Studies show variations in PFAS concentrations across WWTPs, highlighting the importance of aqueous-to-solid partitioning, with sludge from PFOS and PFOA-rich wastewater showing higher concentrations. Research suggests biological mechanisms such as cytochrome P450 monooxygenase, transamine metabolism, and beta-oxidation are involved in PFAS biotransformation, though the effects of precursor changes require further study. Carbon chain length significantly affects PFAS partitioning, with longer chains leading to greater adsorption in sludge. The wastewater's organic and inorganic content is crucial for PFAS adsorption; for instance, higher sludge protein content and divalent cations like calcium and magnesium promote adsorption, while monovalent cations like sodium impede it. In conclusion, these discoveries shed light on the complex interactions among factors affecting PFAS behavior in biosolids. They underscore the necessity for thorough considerations in managing PFAS presence and its impact on environmental systems.

Occurrence and fate of pharmaceuticals and personal care products in a wastewater treatment plant with Bacillus bio-reactor treatment

Pharmaceuticals and personal care products (PPCPs) have attracted wide attention due to their environmental impacts and health risks. PPCPs released through wastewater treatment plants (WWTPs) are estimated to be 80 %. Nevertheless, the occurrence of PPCPs in the WWTPs equipped with Bacillus spec.-based bioreactors (BBR) treatment system remains unclear. In this study, sludge and waste water samples were collected during separate winter and summer sampling campaigns from a typical BBR treatment system. The results indicate that out of 58 target PPCPs, 27 compounds were detected in the waste water (0.06-1900 ng/L), and 23 were found in the sludge (0.6-7755 ng/g dw). Paraxanthine was the chemical of the highest abundance in the influent due to the high consumption of the parent compounds caffeine and theobromine. The profile for PPCPs in the wastewater and sludge exhibited no seasonal variation. Overall, the removal of target PPCPs in summer is more effective than the winter. In the BBR bio-reactor, it was found that selected PPCPs (at ng/L level) can be completely removed. The efficiency for individual PPCP removal was increased from 1.0 % to 50 % in this unit, after target specific adjustments of the process. The effective removal of selected PPCPs by the BBR treatment system is explained by combined sorption and biodegradation processing. The re-occurrence of PPCPs in the wastewater was monitored. Negative removal efficiency was explained by the cleavage of Phase II metabolites after the biotransformation process, and the lack of equilibrium for PPCPs in the sludge of the second clarifier. A compound specific risk quotient (RQ) was calculated and applied for studying the potential environmental risks. Diphenhydramine is found with the highest environmental risk in wastewater, and 15 other PPCPs show negligible risks in sewage sludge.

Occurrence, fate, and remediation for per-and polyfluoroalkyl substances (PFAS) in sewage sludge: A comprehensive review

Addressing per-and polyfluoroalkyl substances (PFAS) contamination is an urgent environmental concern. While most research has focused on PFAS contamination in water matrices, comparatively little attention has been given to sludge, a significant by-product of wastewater treatment. This critical review presents the latest information on emission sources, global distribution, international regulations, analytical methods, and remediation technologies for PFAS in sludge and biosolids from wastewater treatment plants. PFAS concentrations in sludge matrices are typically in hundreds of ng/g dry weight (dw) in developed countries but are rarely reported in developing and least-developed countries due to the limited analytical capability. In comparison to water samples, efficient extraction and cleaning procedures are crucial for PFAS detection in sludge samples. While regulations on PFAS have mainly focused on soil due to biosolids reuse, only two countries have set limits on PFAS in sludge or biosolids with a maximum of 100 ng/g dw for major PFAS. Biological technologies using microbes and enzymes present in sludge are considered as having high potential for PFAS remediation, as they are eco-friendly, low-cost, and promising. By contrast, physical/chemical methods are either energy-intensive or linked to further challenges with PFAS contamination and disposal. The findings of this review deepen our comprehension of PFAS in sludge and have guided future research recommendations.

Occurrence of traffic related trace elements and organic micropollutants in tunnel wash water

Substantially polluted tunnel wash water (TWW) is produced during road tunnel maintenance. Previous literature has reported the presence of trace elements and polycyclic aromatic hydrocarbons (PAHs). However, it was hypothesized that other organic pollutants are present, and more knowledge is needed to prevent environmental harm. This study reveals for the first time the presence of four short- and 17 long-chained per- and polyfluoroalkyl substances (PFASs), three benzothiazoles (BTHs), six benzotriazoles (BTRs), four bisphenols, and four benzophenones in TWW from a Norwegian road tunnel over a period of three years. Concentrations of PAHs, PFASs, BTHs, and BTRs were higher than previously reported in e.g., road runoff and municipal wastewater. Trace elements and PAHs were largely particulate matter associated, while PFASs, BTHs, BTRs, bisphenols, and benzophenones were predominantly dissolved. 26 of the determined contaminants were classified as persistent, mobile, and toxic (PMT) and are of special concern. It was recommended that regulations for TWW quality should be expanded to include PMT contaminants (such as PFPeA, PFBS, BTR, and 4-OH-BzP) and markers of pollution (like 2-M-BTH, 2-OH-BTH, and 2-S-BTH from tire wear particles). These findings highlight the need to treat TWW before discharge into the environment, addressing both, particulate matter associated and dissolved contaminants.

The significance of fluorinated compound chain length, treatment technology, and influent composition on per- and polyfluoroalkyl substances removal in worldwide wastewater treatment plants

Wastewater treatment plants (WWTPs) are deemed major conveyors and point sources of per- and polyfluoroalkyl substances (PFAS) to the environment. This statistical meta-analysis of existing literature from the past 15 years focused on the significance of treatment type for PFAS removal efficiencies and the influence of PFAS sources (domestic vs. industrial) on their removal. Different sampling events, WWTPs across the world, different treatment technologies, configurations, and processes, as well as different PFAS classes and compounds were considered. This study evaluated 13 PFAS analyzed predominantly in 161 WWTPs across the world. The statistical test results revealed that these 13 frequently detected and reported PFAS can be divided into four groups based on their behavior during wastewater treatment, namely (1) C6-10 perfluorocarboxylic acids (PFCAs), (2) C4,5,11,12 PFCAs, (3) C4,6,8 perfluoroalkane sulfonic acids (PFSAs), and (4) C10 PFSA. In this study, biological treatments such as (1) membrane bioreactors, (2) combination of two or more biological treatments, and (3) biofilm processes revealed the highest PFAS removals, although the addition of a tertiary treatment actually had a nonbeneficial effect on PFAS removal. Moreover, a strong statistical correlation was observed between industrial wastewater sources and the presence of high influent PFAS concentrations in the receiving WWTPs. This indicates that industrial sources were the main contributors of the PFAS load in the analyzed WWTPs. Integr Environ Assess Manag 2024;20:59-69. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Microbial and thermal treatment techniques for degradation of PFAS in biosolids: A focus on degradation mechanisms and pathways

Per- and polyfluoroalkyl substances (PFAS) are persistent organic chemicals detected in biosolids worldwide, which have become a significant concern for biosolids applications due to their increasing environmental risks. Hence, it is pivotal to understand the magnitude of PFAS contamination in biosolids and implement effective technologies to reduce their contamination and prevent hazardous aftermaths. Thermal techniques such as pyrolysis, incineration and gasification, and biodegradation have been regarded as impactful solutions to degrade PFAS and transform biosolids into value-added products like biochar. These techniques can mineralize PFAS compounds under specific operating parameters, which can lead to unique degradation mechanisms and pathways. Understanding PFAS degradation mechanisms can pave the way to design the technology and to optimize the process conditions. Therefore, in this review, we aim to review and compare PFAS degradation mechanisms in thermal treatment like pyrolysis, incineration, gasification, smouldering combustion, hydrothermal liquefaction (HTL), and biodegradation. For instance, in biodegradation of perfluorooctane sulfonic acid (PFOS), firstly C-S bond cleavage occurs which is followed by hydroxylation, decarboxylation and defluorination reactions to form perfluoroheptanoic acid. In HTL, PFOS degradation is carried through OH^-catalyzed series of nucleophilic substitution and decarboxylation reactions. In contrast, thermal PFOS degradation involves a three-step random-chain scission pathway. The first step includes C-S bond cleavage, followed by defluorination of perfluoroalkyl radical, and radical chain propagation reactions. Finally, the termination of chain propagation reactions produces very short-fluorinated units. We also highlighted important policies and strategies employed worldwide to curb PFAS contamination in biosolids.

Smouldering to treat PFAS in sewage sludge

Wastewater treatment plants are accumulation points for per- and polyfluoroalkyl substances (PFAS), and are threfore important facilities for PFAS treatment. This study explored using smouldering combustion to treat PFAS in sewage sludge. Base case experiments at the laboratory scale (LAB) used dried sludge mixed with sand. High moisture content (MC) LAB tests, 75% MC sludge by mass, explored impacts of MC on treatment and supplemented with granular activated carbon (GAC) to achieve sufficient temperatures for thermal destruction of PFAS. Additional LAB tests explored using calcium oxide (CaO) to support fluorine mineralization. Further tests performed at an oil-drum scale (DRUM) assessed scale on PFAS removal. Pre-treatment sludge and post-treatment ash samples from all tests were analyzed for 12 PFAS (2C-8C). Additional emissions samples were collected from all LAB tests and analyzed for 12 PFAS and hydrogen fluoride. Smouldering removed all monitored PFAS from DRUM tests, and 4-8 carbon chain length PFAS from LAB tests. For base case tests, PFOS and PFOA were completely removed from sludge; however, high contents in the emissions (79-94% of total PFAS by mass) showed volatilization without degradation. Smouldering high MC sludge at ∼ 900 °C (30 g GAC/kg sand) improved PFAS degradation compared to treatment below 800 °C (<20 g GAC/kg sand). Addition of CaO before smouldering reduced PFAS content in emissions by 97-99% by mass; with minimal PFAS retained in the ash and minimal hydrofluoric acid (HF) production, as the fluorine from the PFAS was likely mineralized in the ash. Co-smouldering with CaO had dual benefits of removing PFAS while minimizing other hazardous emission by-products.

Sewage sludge biochars as effective PFAS-sorbents

The use of sewage sludge to produce biochar-based sorbents for per- and polyfluoroalkyl substances (PFAS) removal from water and soil may be an economically and environmentally sustainable waste management option. This study compared the sorption of six perfluorinated carboxylic acids (PFCAs) by two sewage sludge biochars (SSBCs) and one wood chip biochar (WCBC), dry pyrolyzed at 700 °C. Batch sorption tests were conducted by adding individual PFCAs and a PFCA-mixture to pure biochars and mixtures of biochar and a sandy soil (1.3% TOC). PFAS-sorption to the SSBCs exhibited log-linear biochar-water distribution coefficients (log K_d), comparable to those previously reported for commercial activated carbons (e.g., 5.73 ± 0.02 for perfluorooctanoic acid at 1 µg/L). The strong sorption of PFCAs was attributed to the SSBCs relatively high pore volumes in the pore size range that can accommodate these compounds. Sorption was attenuated by the presence of soil (by factors 3-10), by the presence of a mixture of PFCAs (by factors of 6-532) and by both together (by factors of 8-6581), indicating strongly competitive sorption between PFCA-congeners, and less severe sorption attenuation by soil organic matter. These findings could enable sustainable value chains for SSBs in soil remediation and water filtration solutions.

Novel method in emerging environmental contaminants detection: Fiber optic sensors based on microfluidic chips

Recently, human industrial practices and certain activities have caused the widespread spread of emerging contaminants throughout the environmental matrix, even in trace amounts, which constitute a serious threat to human health and environmental ecology, and have therefore attracted the attention of research scholars. Different traditional techniques are used to monitor water pollutants, However, they still have some disadvantages such as high costs, ecological problems and treatment times, and require technicians and researchers to operate them effectively. There is therefore an urgent need to develop simple, inexpensive and highly sensitive methods to sense and detect these toxic environmental contaminants. Optical fiber microfluidic coupled sensors offer different advantages over other detection technologies, allowing manipulation of light through controlled microfluidics, precise detection results and good stability, and have therefore become a logical device for screening and identifying environmental contaminants. This paper reviews the application of fiber optic microfluidic sensors in emerging environmental contaminant detection, focusing on the characteristics of different emerging contaminant types, different types of fiber optic microfluidic sensors, methodological principles of detection, and specific emerging contaminant detection applications. The optical detection methods in fiber optic microfluidic chips and their respective advantages and disadvantages are analyzed in the discussion. The applications of fiber optic biochemical sensors in microfluidic chips, especially for the detection of emerging contaminants in the aqueous environment, such as personal care products, endocrine disruptors, and perfluorinated compounds, are reviewed. Finally, the prospects of fiber optic microfluidic coupled sensors in environmental detection and related fields are foreseen.

Review of influence of critical operation conditions on by-product/intermediate formation during thermal destruction of PFAS in solid/biosolids

Poly- and perfluoroalkyl substances (PFAS) are a large group of synthetic organofluorine compounds. Over 4700 PFAS compounds have been produced and used in our daily life since the 1940s. PFAS have received considerable interest because of their toxicity, environmental persistence, bioaccumulation and wide existence in the environment. Various treatment methods have been developed to overcome these issues. Thermal treatment such as combustion and pyrolysis/gasification have been employed to treat PFAS contaminated solids and soils. However, short-chain PFAS and/or volatile organic fluorine is produced and emitted via exhaust gas during the thermal treatment. Combustion can achieve complete mineralisation of PFAS at large scale operation using temperatures >1000 °C. Pyrolysis has been used in treatment of biosolids and has demonstrated that it could remove PFAS completely from the generated biochar by evaporation and degradation. Although pyrolysis partially degrades PFAS to short-chain fluorine containing organics in the syngas, it could not efficiently mineralise PFAS. Combustion of PFAS containing syngas at 1000 °C can achieve complete mineralisation of PFAS. Furthermore, the by-product of mineralisation, HF, should also be monitored due to its low regulated atmospheric discharge values. Alkali scrubbing is normally required to lower the HF concentration in the exhaust gas to acceptable discharge concentrations.

Per- and polyfluoroalkyl substances (PFAS) in sludge from wastewater treatment plants in Sweden - First findings of novel fluorinated copolymers in Europe including temporal analysis

Thousands of per- and polyfluoroalkyl substances (PFAS) are on the global market, while only a minor proportion is monitored regularly in the environment. Wastewater treatment plants (WWTPs) have been suggested to be a point source for PFAS to the environment due to emission of effluent and sludge. In this study, 81 PFAS including two rarely studied perfluoroalkyl sulfonamide-based (FASA) copolymers were analyzed in sludge samples to understand the usage of PFAS in the society. Sludge samples (n = 28) were collected at four WWTPs in Sweden between 2004 and 2017. The total levels of 79 measured PFAS were between 50 and 1124 ng/g d.w. All sludge samples showed detectable levels of both C8- and C4-FASA-based copolymers. The concentrations of the FASA-based copolymers were proposed to be reported in fluorinated side-chain equivalents (FSC eq.), in order to compare the levels of the copolymers with the other neutral and anionic PFAS, as no authentic standards were available. The concentrations of the FASA-based copolymers in sludge were between 1.4 and 22 ng FSC eq./g d.w. A general predomination of precursor and intermediate compounds was observed. A lower contribution of perfluoroalkyl carboxylic acids was noted for the WWTPs more influenced by domestic emission when compared with more influenced by industrial emission. An overall declining trend in the total PFAS concentration was seen between the years 2004 and 2017. The present study observed a shift from the C8-based chemistry toward shorter chain lengths, included a declining trend for C8-FASA-based copolymer over the entire study period. These findings further demonstrate the occurrence of side-chain fluorinated copolymers in Sweden and that sludge is a useful matrix to reflect the usage of PFAS in society and the potential for environmental exposure.

6:2 Chlorinated polyfluoroalkyl ether sulfonate as perfluorooctanesulfonate alternative in the electroplating industry and the receiving environment

Electroplating industry is an important application field of per- and polyfluoroalkyl substances (PFASs) as the chromium mist suppressants. 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFAES) and perfluorooctanesulfonate (PFOS) have been the two widely used mist suppressants, and after the ban of PFOS, 6:2 Cl-PFAES will become the dominant suppressant. The behavior and mechanisms of 6:2 Cl-PFAES in the electroplating industry and the receiving environment were studied and compared with PFOS. 6:2 Cl-PFAES behaved similarly with PFOS due to their similar chemical structure. However, some difference exists for the relatively stronger hydrophobicity of 6:2 Cl-PFAES. Up to 35.7 mg/L of PFOS and 13.4 mg/L of 6:2 Cl-PFAES were found in the industrial wastewater influents, and were effectively reduced to 0.3-0.8 mg/L by the interaction with chromium hydroxide through hydrophobic interaction and ligand exchange. The stronger hydrophobicity of 6:2 Cl-PFAES than PFOS resulted in its accumulation in the surface of foams and comparable or less removal during the industrial and municipal wastewater treatment. 6:2 Cl-PFAES exhibited higher bioaccumulation potential than PFOS in the surface water. 6:2 Cl-PFAES emitted by both mists and water may pose health risks to humans. More attentions towards 6:2 Cl-PFAES are needed after the replacement of PFOS by it in the electroplating industry as a global contaminant of emerging concerns.

Global patterns and temporal trends of perfluoroalkyl substances in municipal wastewater: A meta-analysis

Despite increasing regulatory efforts to reduce production of per- and polyfluoroalkyl substances (PFAS), continued human and ecological exposure to PFAS has led to concerns about historical releases. Municipal wastewater treatment plants (WWTPs) provide important conduits between waste sources and the environment. We present a meta-analysis of results reported in 44 peer-reviewed publications that include 460 influent and 528 effluent samples, collected from 21 countries, for which some or all of five perfluorinated carboxylic acids (PFCAs) and three perfluorinated sulfonic acids (PFSAs) were measured. Our meta analysis revealed global patterns and trends that, to our knowledge, have not been reported elsewhere. Regression analyses of samples collected from 2004 to 2020 quantified the temporal trends of global wastewater effluent concentrations of each of the PFAS and the corresponding mean concentration for each country. Although legacy compounds, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), have been reported with the highest measured concentrations, their global temporal trends are lowest of all PFAS considered. Concentrations of most PFAS analyzed in wastewater in the United States have not changed significantly with time, whereas reported PFAS concentrations in wastewater effluent from China have increased from 11% to 37% per year. In addition, our results show significant positive correlations between previous wastewater effluent concentrations of individual PFAS and the gross domestic product per capita of each country. Our analysis of this global data set also confirmed conclusions from previous studies on smaller data sets: (i) none of the PFAS studied are effectively removed by conventional treatment processes; (ii) effluents from treatment plants that include a significant industrial component to their influent tend to have higher PFAS concentrations; and (iii) the few studies that measured both aqueous concentrations and concentrations adsorbed to suspended particulate matter (SPM) indicate that PFAS adsorbed to SPM can contribute significantly to the total PFAS load.

Distributions and sources of traditional and emerging per- and polyfluoroalkyl substances among multiple environmental media in the Qiantang River watershed, China

The presence of per- and polyfluoroalkyl substances (PFASs) in the food chain poses a threat to human health. Water and the atmosphere are the major transport pathways for PFASs in the environment, while water, soil and sediment are sinks. Herein, the concentrations and distributions of traditional and emerging PFASs in multi-environmental media samples in the Qiantang River watershed were comprehensively investigated. Twenty-five PFASs, including seven emerging PFASs, were identified. The concentrations in water, soil, sediment and PM2.5 ranged from 3.58 to 786 ng L-1, 0.72 to 12.3 ng g-1, 0.73 to 6.60 ng g-1, and 93.9 to 255 pg m-3, respectively, with mean concentrations of 149 ng L-1, 4.70 ng g-1, 4.31 ng g-1, and 156 pg m-3. Perfluorooctanoic acid (PFOA) was the dominant contaminant in water, soil, and sediment, and perfluoropentanoic acid (PFPeA) was the dominant contaminant in PM2.5. Hexafluoropropylene oxide-dimer acid (HFPO-DA) and 6 : 2 chlorinated polyfluorinated ether sulfonate (6 : 2 Cl-PFESA), as substitutes for PFOA and perfluorooctane sulfonate (PFOS), were detected, indicating the gradual replacement of traditional PFOA and PFOS in this area. Perfluoro-3,6-dioxaheptanoic acid (NFDHA), as a component of the aqueous film-forming foam FN-3, was first detected in this area. Short-chain PFASs were mainly distributed in water and PM2.5, while long-chain PFASs were distributed in the solid phase, such as soil, sediment, and PM2.5. Based on principal component analysis (PCA), the major PFAS sources were emulsifiers from fluorine polymerization and surface-active agents from the textile, papermaking, leather, and other industries. In addition, correlation analysis showed that water was the main source and transport pathway of short-chain perfluoroalkyl carboxylic acid (PFCA), HFPO-DA, and NFDHA in this area, while the atmosphere combined with PM2.5 was the main transport pathway for both short- and long-chain PFCAs, PFOS, and 6 : 2 Cl-PFESA.

Formation and fate of perfluoroalkyl acids (PFAAs) in a laboratory-scale urban wastewater system

The fate and formation of perfluoroalkyl acids (PFAAs) have been investigated during wastewater treatment processes but studies for the entire urban wastewater system comprising the sewage transport and wastewater and sludge treatment processes are scarce. This work performs an integrated assessment of the formation and fate of PFAAs in the urban wastewater system together with their behavior in separate components of the system. To achieve this, PFAAs were monitored over five weeks in a laboratory-scale urban wastewater system comprising sewer reactors, a wastewater treatment reactor, and an anaerobic sludge digester. The system was fed with real domestic wastewater. The total mass of 11 PFAAs flowing out of the laboratory wastewater system significantly (p < 0.05) increased by 112 ± 14 (mean ± standard error)% compared to that entering the system. Formation of PFAAs was observed in all three biological processes of the system. In anaerobic sewer process, perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), and perfluorooctane sulfonate (PFOS) exhibited significant formation (p < 0.05) with the mass flow increased by 79 ± 24%, 109 ± 31%, and 57 ± 17%, respectively. During the wastewater treatment process, perfluorohexanoic acid (PFHxA), perfluorooctanoic acid (PFOA), and perfluorododecanoic acid (PFDoDA) demonstrated significant increase (p < 0.05) in their mass flows by 176 ± 56%, 92 ± 21%, and 516 ± 184%, respectively. In contrast, only PFHxA was found to significantly (p < 0.05) increase by 130 ± 40% during anaerobic digestion process. The total mass of 11 PFAAs discharged through the effluent (201 ± 24 ng day^-1) was 5 times higher than that through the digested sludge (29 ± 6 ng day^-1).

Occurrence and risk assessment of trace organic contaminants and metals in anaerobically co-digested sludge

Anaerobic co-digestion of sludge increases biogas production and maintains anaerobic digestion stability. However, it is unclear whether the addition of co-substrates may increase the concentration of trace organic contaminants (TrOCs) and metals, limiting potential resource recovery opportunities when applied to agricultural land. This study explored the occurrence of 20 TrOCs and 18 metals in wastewater sludge anaerobically co-digested with beverage rejects (cola, beer and juice) and food wastes. TrOCs results showed that cola reject caused an accumulation of caffeine in final digestate. Bisphenol A also significantly increased in food waste co-digestion when compared with the mono-digestion (control). No significant difference in TrOCs was observed in the juice reject co-digestion. Analysis of the metal composition revealed a significant increase in Cr and Al in juice reject co-digested sludge. While restaurant food waste increased concentrations of K and Ca, both of which may be beneficial when applied to land. All metals in this study were below the maximum permissible concentrations specified for agricultural land use in Australia. Environmental risk assessment of sludge when used as soil fertiliser, showed that caffeine, diuron, triclocarban, triclosan, Cu and Zn exhibited high risks, with the largest risk quotient (RQ) posed by caffeine. Estrone and naproxen implied medium risks, and ibuprofen implied a high risk except for the co-digestion using cola reject (RQ = 0.9, medium risk). The results emphasise the importance for wastewater utility operators to understand the impact of co-substrate selection on the quality of sludge to minimise environmental risk from the use of biosolids on agricultural land.

An amine-functionalized olefin-linked covalent organic framework used for the solid-phase microextraction of legacy and emerging per- and polyfluoroalkyl substances in fish

Due to the environmental persistence and various health problems associated with per- and polyfluoroalkyl substances (PFASs), they have come under increased public scrutiny. However, the efficient extraction of PFASs from complex media remains challenging. Herein, an olefin-linked covalent organic framework (COF-CN) has been prepared via a Knoevenagel condensation reaction, followed by reduction using LiAlH₄ to form an amine-functionalized COF (COF-NH₂). The characterization results demonstrated that the crystal structure was maintained during the post-modification step. Isothermal and kinetic adsorption studies showed the higher affinity of COF-NH₂ toward PFASs. Based on density functional theory, the adsorption mechanism of the stable six-member-ring structure formed between COF-NH₂ and PFASs via hydrogen bonding was tentatively revealed. After optimizing the solid-phase microextraction parameters, legacy and emerging PFASs were efficiently extracted from fish using the COF-NH₂ coating, followed by detection using ultra-performance liquid chromatography-tandem mass spectrometry. The method exhibited ideal linearity, low limits of quantification, excellent precision, and high relative recoveries. Finally, the bioconcentration kinetics for goldfish was studied, which can provide a feasible platform for investigating the accumulate ion and toxicity of PFASs.

Assessment of a wide array of organic micropollutants of emerging concern in wastewater treatment plants in Greece: Occurrence, removals, mass loading and potential risks

Exploring the contamination profile of multi-class emerging contaminants (ECs) in wastewater is highly desirable. To this end, the occurrence, removal, mass loading and risks associated with a large panel of pharmaceuticals and personal care products, illicit drugs, perfluorinated compounds and organophosphate flame retardants in two wastewater treatment plants (WWTPs) in the region of Thessaloniki (Greece) after a survey is illustrated. Influent and effluent wastewaters were submitted to solid phase extraction on Oasis HLB cartridges, followed by ultra-high-performance liquid chromatography Orbitrap high-resolution mass spectrometry (UHPLC-Orbitrap MS). Influent concentrations in both WWTPs were notably higher than effluent, with caffeine, acetaminophen, irbesartan and valsartan being the most ubiquitous compounds, exhibiting elevated concentrations. Average effluent concentrations ranged from below the method quantification limits (<MQL) to remarkably high values (μg L^-1 scale), such as for caffeine, acetaminophen, diclofenac, irbesartan and valsartan, among others. Removal efficiencies ranged between -273% for lamotrigine and 100%, i.e., for the UV filter BP1. Notably, the polar compounds such as cytarabine, methotrexate and capecitabine were removed at a rate >80% in both WWTPs, allowing the correlation between logK_ow and removals. Interesting trends for the illicit drugs were revealed by means of mass loading estimation, as in the case of benzoylecgonine (71.6 mg/day/1000 inhabitants). Ecotoxicological risk assessment was evaluated for both single components and mixture, using three approaches: risk quotient (RQ), risk quotient considering frequency (RQ_f) and toxic units (TU). Irbesartan and telmisartan posed a high risk in all trophic levels, while fish was the most sensitive taxa for diclofenac. This work aspires to intensify the surveillance programs for the receiving water bodies, as well as to motivate the investigation of toxicity to non-target organisms.

Concentration profiles of per- and polyfluoroalkyl substances in major sources to the environment

A review of published literature was conducted to present the concentrations and composition profiles of per- and polyfluoroalkyl substances (PFAS) from significant sources to the environment. The major sources of PFAS to the environment are categorized under direct and indirect sources. The characteristic compounds and concentrations are summarized as found from direct sources such as manufacturing facilities, aqueous film-forming foam (AFFF) applications, metal coating operations, and textile and paper coating operations; and from indirect sources such as landfills and wastewater treatment plants (WWTPs). The major findings are: 1) among the aqueous matrices for which data were reviewed, groundwater impacted by AFFF contamination showed the highest median concentrations for both perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), while the second-highest median concentrations were associated with landfill leachates for PFOA and metal-plating sources for PFOS; 2) many of the unknown polyfluorinated precursors present in AFFF-impacted sites could potentially convert to persistent PFAS by abiotic or biotic transformation, and therefore could act as the long-term source of contamination to the environment; 3) part per billion (ppb) concentrations of PFAS were detected in water bodies surrounding fluorochemical manufacturing plants; 4) in consumer products such as textile, paper, and personal care products, PFOA concentrations were an order of magnitude higher compared to other PFAS; 5) biotransformation products such as fluorotelomer carboxylic acids (FTCAs) and perfluoroalkyl acids (PFAAs) are detected in landfill leachates and WWTP effluents; and 6) many studies have shown increased PFAA concentrations in WWTP effluents compared to influents. This work provides a comprehensive review of the literature on the PFAS concentration and composition trends of select non-polymeric PFAS in different sources.

Exploring the integrity of targeted PFASs in extracted wastewater samples during transport and storage stages

Little information exists on the effects of shipping and handling on per- and polyfluoroalkyl substances (PFASs) in environmental samples. Thus, we evaluated the integrity of dried wastewater extracts and the sensitivity of our high-resolution mass spectrometry (HRMS) instrument to perform such analyses by monitoring 13 representative PFASs in samples extracted, evaporated, and stored at room temperature up to one month. Relative to zero-day recoveries of six detected PFASs ranged between 94 and 124% (RSD <38%) for influents, between 88 and 126% (RSD <18%) for effluents after 28 days. Larger variabilities are tentatively associated with the lack of specific mass-labeled standards and the interactions between analytes and remaining matrix components over time. In a second stage, a mix of local and international dry-shipped wastewater samples were analyzed and the same PFASs were quantified. Up to six PFASs were identified, with median concentrations ranging from 1.3 (perfluoro butyl sulfonate (PFBS)) to 7.7 ng/L (perfluoro hexanoic acid (PFHxA)) and from 1.5 (PFBS) to 13.8 ng/L (PFHxA) in local influents and effluents respectively; and from 0.7 (perfluoro hexyl sulfonate (PFHxS)) to 52.8 ng/L (PFHxA) and from 0.5 (PFHxS) to 21.4 ng/L (PFHxA) in Greek influents and effluents, respectively. The importance of this study lies on the need to consider the wider recovery shifts and expanded variability ranges of PFASs derived from the transport and storage times of dried extracts, particularly when applied to HRMS and wide-scope screening approaches.

Distribution, behaviour, bioavailability and remediation of poly- and per-fluoroalkyl substances (PFAS) in solid biowastes and biowaste-treated soil

Aqueous film-forming foam, used in firefighting, and biowastes, including biosolids, animal and poultry manures, and composts, provide a major source of poly- and perfluoroalkyl substances (PFAS) input to soil. Large amounts of biowastes are added to soil as a source of nutrients and carbon. They also are added as soil amendments to improve soil health and crop productivity. Plant uptake of PFAS through soil application of biowastes is a pathway for animal and human exposure to PFAS. The complexity of PFAS mixtures, and their chemical and thermal stability, make remediation of PFAS in both solid and aqueous matrices challenging. Remediation of PFAS in biowastes, as well as soils treated with these biowastes, can be achieved through preventing and decreasing the concentration of PFAS in biowaste sources (i.e., prevention through source control), mobilization of PFAS in contaminated soil and subsequent removal through leaching (i.e., soil washing) and plant uptake (i.e., phytoremediation), sorption of PFAS, thereby decreasing their mobility and bioavailability (i.e., immobilization), and complete removal through thermal and chemical oxidation (i.e., destruction). In this review, the distribution, bioavailability, and remediation of PFAS in soil receiving solid biowastes, which include biosolids, composts, and manure, are presented.

Occurrence and ecotoxicological risk assessment of perfluoroalkyl substances in water of lakes along the middle reach of Yangtze River, China

Polyfluoroalkyl substances (PFASs) are widely distributed in aquatic environment, and the potential ecological risk of PFASs has become a new challenge in recent years. But there were few integrated studies about the distribution, source appointment and risk assessment of PFASs in water of lakes along the middle reach of Yangtze River, China. Hence, this study investigated the pollution characteristics, source apportionment, ecological risks assessment of eleven PFASs from the surface water in this region. The total concentrations of PFASs (∑PFASs) ranged from 12.43 to 77.44 ng L^-1 in this region. The ∑PFASs in Hong and Poyang Lakes were higher than those in Dongting Lake and middle reach of Yangtze River (p < 0.05). The compositions of PFASs in the middle reach of Yangtze River and along three lakes were similar, being with a larger proportion of short-chain PFACs. The food packaging and metal plating sources were identified as the main sources by two models. The total risk quotients (∑RQs) showed the ecological risk for algae in the middle reach of Yangtze River, Dongting and Poyang Lakes were negligible, but the low risk in some sites of Hong Lake. The EDIs of ∑PFASs were much lower than the tolerable daily intake recommended by the European Food Safety Authority. The results of this study were significant for developing effective strategies (e.g. short-chain substitution and restriction) of controlling PFASs pollution in the middle reach of Yangtze River and along lakes.

Serum per- and polyfluoroalkyl substance (PFAS) concentrations and predictors of exposure among pregnant African American women in the Atlanta area, Georgia

Exposure to per- and polyfluoroalkyl substances (PFAS) has been associated with adverse health outcomes, especially when exposure occurs within sensitive time windows such as the pre- and post-natal periods and early childhood. However, few studies have focused on PFAS exposure distribution and predictors in pregnant women, especially among African American women. We quantified serum concentrations of the four most common PFAS collected in all 453 participants and an additional 10 PFAS in 356 participants who were pregnant African American women enrolled from 2014 to 2018 in Atlanta, Georgia, and investigated the sociodemographic predictors of exposure. Additional home environment and behavior predictors were also examined in 130 participants. Perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) were detected in >95% of the samples with PFOS having the highest concentrations (geometric mean (GM) 2.03 ng/mL). N-Methyl perfluorooctane sulfonamido acetic acid (NMeFOSAA), perfluoropentanoic acid (PFPeA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were found in 40-50% of the samples, whereas the detection frequencies for the other six PFAS were below 15%. When compared to National Health and Nutrition Examination Survey (NHANES) participants matching sex, race, and age with this study, our results showed similar concentrations of most PFAS, but higher concentrations of PFHxS (GM 0.99 ng/mL in this study; 0.63 and 0.4 ng/mL in NHANES, 2014-2015 and 2016-2017 cycles). A decline in concentrations over the study period was found for most PFAS but not PFPeA. In adjusted models, education, sampling year, parity, BMI, tobacco and marijuana use, age of house, drinking water source, and cosmetic use were significantly associated with serum PFAS concentrations. Our study reports the first PFAS exposure data among pregnant African American women in the Atlanta area, Georgia. The identified predictors will facilitate the setting of research priorities and enable development of exposure mitigation strategies.

A review of the occurrence, transformation, and removal of poly- and perfluoroalkyl substances (PFAS) in wastewater treatment plants

Poly- and perfluoroalkyl substances (PFAS) comprise more than 4,000 anthropogenically manufactured compounds with widescale consumer and industrial applications. This critical review compiles the latest information on the worldwide distribution of PFAS and evaluates their fate in wastewater treatment plants (WWTPs). A large proportion (>30%) of monitoring studies in WWTPs were conducted in China, followed by Europe (30%) and North America (16%), whereas information is generally lacking for other parts of the world, including most of the developing countries. Short and long-chain perfluoroalkyl acids (PFAAs) were widely detected in both the influents (up to 1,000 ng/L) and effluents (15 to >1,500 ng/L) of WWTPs. To date, limited data is available regarding levels of PFAS precursors and ultra-short chain PFAS in WWTPs. Most WWTPs exhibited low removal efficiencies for PFAS, and many studies reported an increase in the levels of PFAAs after wastewater treatment. The analysis of the fate of various classes of PFAS at different wastewater treatment stages (aerobic and/aerobic biodegradation, photodegradation, and chemical degradation) revealed biodegradation as the primary mechanism responsible for the transformation of PFAS precursors to PFAAs in WWTPs. Remediation studies at full scale and laboratory scale suggest advanced processes such as adsorption using ion exchange resins, electrochemical degradation, and nanofiltration are more effective in removing PFAS (~95-100%) than conventional processes. However, the applicability of such treatments for real-world WWTPs faces significant challenges due to the scaling-up requirements, mass-transfer limitations, and management of treatment by-products and wastes. Combining more than one technique for effective removal of PFAS, while addressing limitations of the individual treatments, could be beneficial. Considering environmental concentrations of PFAS, cost-effectiveness, and ease of operation, nanofiltration followed by adsorption using wood-derived biochar and/or activated carbons could be a viable option if introduced to conventional treatment systems. However, the large-scale applicability of the same needs to be further verified.

Distribution and fate of per- and polyfluoroalkyl substances (PFAS) in wastewater treatment facilities

Anthropogenic compounds known as per- and polyfluoroalkyl substances (PFAS) represent a major class of contaminants of emerging concern composed of nearly 5000 chemicals. Many PFAS are persistent, bioaccumulative and toxic, and their widespread use makes their environmental distribution a growing concern. Wastewater treatment facilities (WWTFs) are a conduit of PFAS to the environment, integrating common household products from municipal sewage, industrial wastewater sources, septic materials, and firefighting wastewaters in effluent and sludge. This study investigated the distribution and fate of twenty-four PFAS within six New Hampshire municipal WWTFs applying a range of biological and disinfection unit processes. PFAS quantification was conducted using two approaches: (1) liquid chromatography with tandem mass spectrometry (LC-MS/MS) of 24 known compounds and (2) a total oxidizable precursor assay (TOP assay) followed by LC-MS/MS to determine the total oxidizable PFAS concentration. Of the 24 PFAS analyzed, up to 7 and 12 constituents were detected in influent and effluent of WWTFs, respectively, with concentrations ranging from 30 to 128 ng L-1 in March. Effluent ΣPFAS concentration increased during July, with concentrations between 70 and 198 ng L-1 for the same detected constituents. Short-chain PFAS were dominant in both influent and effluent, while long-chain compounds dominated in WWTF sludge. The increase in terminal end-products after oxidation by the TOP assay indicates the presence of unquantified PFAS precursors in both influent and effluent. A significantly lower proportion of oxidizable PFAS precursors were detected in July influent and effluent relative to March, indicating a possible role of season or temperature on microbial transformation of these compounds prior to reaching WWTFs and during treatment. These results provide new insight into PFAS distribution and fate during two seasons in New England municipal WWTFs.

Legacy and emerging per- and polyfluoroalkyl substances (PFASs) in Australian biosolids

Biosolids samples were collected from 19 Australian WWTPs during 2018 that cover a range of catchment types (urban, rural, industrial waste discharges) and treatment technologies. Samples were analysed for 44 PFAS using isotope dilution and alkaline extraction coupled with quantification with LC-MS/MS. The Σ₄₄PFAS mean concentration was 260 ng/g dry weight (dw) and ranged between 4.2 and 910 ng/g dw. The dominant compound class detected were the di-substituted phosphate esters (Σ₃PAPs mean 140 ng/g dw; range ND - 730 ng/g dw) which contributed 45% of the total mean Σ₄₄PFAS mass, followed by perfluoroalkyl carboxylic acids (Σ₁₁PFCAs mean 39 ng/g dw; range 2.3-120 ng/g dw) contributing 17%, and the perfluoroalkyl sulfonates (Σ₈PFSAs mean 28 ng/g dw; range 0.9-220 ng/g) which contributed 16%. Using the population data supplied by the participating WWTPs, the mean annual estimated biosolids-associated PFAS contribution is 6 mg per person per year and ranged between 0.6 mg and 15 mg. A similar population normalised concentration regardless of WWTP, region or capacity suggests that the domestic environment provides the baseline PFAS loading. Statistically significant higher Σ₄₄PFAS and PFOS concentrations were observed at urban locations. A weak correlation was observed between annual mass of PFAS associated with each individual WWTP and their percentage industrial waste contribution. This may be important for elevated PFAS concentrations observed in WWTPs with higher industrial waste inputs and requires further research.

Effects of co-existence of organic matter and microplastics on the rejection of PFCs by forward osmosis membrane

Perfluorinated chemical (PFC)-based materials have been widely applied in industry. In this study, the influence of PFCs on the physicochemical properties of membranes and that of the co-existence of organic matter and microplastics on the removal rate in the process of forward osmosis (FO) was examined. The water flux, reverse salt flux, and rejection of PFCs were evaluated under w and w/o contaminants. The lowest rejection rates of PFCs in FO membranes were observed to be 92.2% and 90.4% for FO-TFC and PA-Aqua FO membranes, respectively. The main rejection mechanism of the FO membrane is the sieving effect (p-value: PA-TFC-0.015, PA-Aqua-0.002) based on molecular volume, which is more dominant than the electrostatic repulsive force and hydrophobic interaction, the major rejection mechanisms of existing trace contaminants. In addition, we observed that the effects of co-existing pollutants in raw water have an insignificant effect on the rejection of PFCs because of the physical and chemical stability of PFCs. According to the results of this study, using the FO membrane, PFCs can effectively control not only their self-existence but also when contaminants co-exist with them in water bodies.

Formation and partitioning behaviour of perfluoroalkyl acids (PFAAs) in waste activated sludge during anaerobic digestion

The formation and fate of perfluoroalkyl acids (PFAAs) in sludge during anaerobic digestion (AD) is of global importance since the sludge is a significant source of PFAAs to the environment. The formation of PFAAs from polyfluorinated compounds, namely PFAA precursors, is poorly understood in AD. This study aims to investigate the formation of PFAAs from precursors and their partitioning behaviour in waste activated sludge (WAS) during AD process. To achieve this, three isotope-labelled PFAAs were spiked and monitored along with indigenous PFAAs and precursors over eight weeks in a laboratory-scale anaerobic digester, fed with sludge from a local wastewater treatment plant and operated with a hydraulic retention time of 12 days under 35 ℃. In addition to isotope-labelled PFAAs, twelve native PFAAs and eight polyfluorinated compounds were detected in the feed and digested sludges. A mass-balance model, validated by the spiking experiment, was applied to predict the concentrations of PFAAs and precursors assuming no formation/degradation in AD. The measured concentrations of short-chain PFAAs (perfluoroalkyl carboxylates (PFCAs): C < 8; perfluoroalkane sulfonates (PFSAs): C < 6) in the AD sludge were significantly (p < 0.05) higher than the model-predicted concentrations, indicating the formation of these PFAAs from precursors in AD. In contrast, the formation of long-chain PFAAs (PFCAs: C ≥ 8; PFSAs: C ≥ 6) was not observed. Moreover, the degradation of two polyfluoroalkyl phosphates (PAPs) (6:2 PAP and 6:2/8:2 diPAP) occurred, evidenced by their measured concentrations that were statistically lower than the mass-balance predictions. Further, the AD process reduced the amount of PFAAs absorbed/adsorbed to sludge, particularly for the long-chain ones, due to the breakdown of solids.

Assessment of PFAS fate, transport, and treatment inhibition associated with a simulated AFFF release within a WASTEWATER treatment plant

Sequencing batch reactors (SBRs) were operated for 36 days to simulate the potential wastewater treatment impacts as well as fate and transport of per- and polyfluoroalkyl substances (PFAS) that could be associated with a release of alcohol resistant aqueous film forming foam (AR-AFFF) from on-site methanol fire suppression systems. The results of this study indicate that two days of exposure to AFFF were associated with small reductions in mixed liquor solids content and nitrification rates. No impacts on denitrification or biological phosphorus removal were observed. The addition of AFFF was associated with increases in 6:2 fluorotelomer sulfonate (6:2 FTS) in influent, effluent, and solids samples in the SBR. The following biotransformation pathway is proposed: an unidentified fluorotelomer precursor quickly degraded to 6:2 FTS, which then slowly degraded to several identified degradation intermediates and terminal, short-chain perfluorocarboxylic acid products. Data for 6:2 FTS, which was used as a proxy for AFFF-associated PFAS, were extrapolated to estimate that a removal of approximately 70% of AFFF via effluent and solids wasting would occur after 4 days at a full-scale treatment plant. This information can be used to better understand potential impacts on downstream processes, including potable reuse and biosolids production.

Association between prenatal exposure to perfluoroalkyl substances and respiratory tract infections in preschool children

BACKGROUND

Prenatal exposure to perfluoroalkyl substances (PFAS) is considered to affect adversely the immune function. However, the effect of prenatal PFAS exposure on respiratory tract infections (RTIs) in children is unclear. Thus, we evaluated whether cord blood PFAS levels were associated with RTI in the first 5 years of life.

METHODS

The Shanghai Prenatal Cohort is an on-going birth cohort, which included all the mothers during pregnancy. Children were followed by paediatricians once a year after birth. The levels of 10 PFAS in cord blood were tested using liquid chromatography-mass spectrometry. RTIs were diagnosed based on face-to-face interviews with the parents and review of medical records. Immunoglobulin G (IgG) and immunoglobulin E (IgE) levels, as biomarkers of humoral immunity, were assessed using enzyme-linked immunosorbent assay at age 5 years. Multivariable logistic and linear regression models were applied to study the association between prenatal PFAS exposure and RTIs.

RESULTS

A total of 743 children completed the follow-up, 344 of them had detail information of cord blood PFAS, IgG, and IgE concentrations. Eight PFAS were detected in more than 90% of the cord blood samples, except for perfluoroheptanoic acid (PFHpA) and perfluorooctane sulfonamide (FOSA). During the 5-year follow-up period, the frequency of RTIs increased with age, reaching a peak at age 4. Moreover, 20.6% of the children were diagnosed with recurrent RTIs. Children with recurrent RTIs had higher prenatal perfluorobutane sulfonic acid (PFBS) concentration. Higher prenatal PFBS concentration was positively associated with total RTI frequency (β = 6.05, 95% CI [0.84, 11.26]) in first 5 years of life and negatively associated with IgG level (β = -0.82, 95% CI [-1.67, -0.01]) at age 5.

CONCLUSIONS

Children with higher prenatal PFBS were more vulnerable to RTIs in early life, which may be attributed to immunosuppression of IgG production. These findings need to be further verified in larger prospective studies.

Environmental levels and human body burdens of per- and poly-fluoroalkyl substances in Africa: A critical review

Per- and polyfluoroalkyl substances (PFASs) are known organic pollutants with adverse health effects on humans and the ecosystem. This paper synthesises literature about the status of the pollutants and their precursors, identifies knowledge gaps and discusses future perspectives on the study of PFASs in Africa. Limited data on PFASs prevalence in Africa is available because there is limited capacity to monitor PFASs in African laboratories. The levels of PFASs in Africa are higher in samples from urban and industrialized areas compared to rural areas. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are the dominant PFASs in human samples from Africa. Levels of PFOS and PFOA in these samples are lower than or comparable to those from industrialized countries. PFOA and PFOS levels in drinking water in Africa are, in some cases, higher than the EPA drinking water guidelines suggesting potential risk to humans. The levels of PFASs in birds' eggs from South Africa are higher, while those in other environmental media from Africa are lower or comparable to those from industrialized countries. Diet influences the pollutant levels in fish, while size and sex affect their accumulation in crocodiles. No bioaccumulation of PFASs in aquatic systems in Africa could be confirmed due to small sample sizes. Reported sources of PFASs in Africa include municipal landfills, inefficient wastewater treatment plants, consumer products containing PFASs, industrial wastewater and urban runoff. Relevant stakeholders need to take serious action to identify and deal with the salient sources of PFASs on the African continent.

Non-target and suspect screening of per- and polyfluoroalkyl substances in Chinese municipal wastewater treatment plants

Wastewater treatment plant (WWTP) is one of the major sources of per- and polyfluoroalkyl substances (PFASs) to the aquatic environment. In this study, wastewater samples were collected from 17 WWTPs in 17 cities of China to investigate emerging PFASs in WWTPs. To comprehensively identify PFASs in the wastewater samples, an integrated suspect screening, homologue-based and fragment-based non-target screening method is proposed. Sixty-three PFASs from 13 classes (25 subclasses) were identified, including 14 legacy and 49 emerging PFASs, and this study is the first to report on 12 of these PFASs. We found that emerging PFASs concentration had a significantly positive correlation with the gross domestic product, indicating more substitution of legacy PFASs in the developed area of China. We also analyzed the removal of the 13 PFAS classes, and found that all discovered PFAS classes were not completely removed after the treatment process, whereas the class of perfluoroalkyl ether alcohols significantly increased. All of these results imply that the release of emerging or unknown PFASs from WWTPs is a universal but not negligible problem in China.

Removal of COD, NH4-N, and perfluorinated compounds from wastewater treatment plant effluent using ZnO-coated activated carbon

This study investigated the removal of chemical oxygen demand (COD), NH₄-N, and perfluorinated compounds (PFCs) in the effluent from a wastewater treatment plant (WWTP) using ZnO coated activated carbon (ZnO/AC). Results suggested that the optimal dosage of the ZnO/AC was 0.8 g/L within 240 min of contact time, at which the maximum removal efficiency of COD was approximately 86.8%, while the removal efficiencies of PFOA and PFOS reached 86.5% and 82.1%. In comparison, the removal efficiencies of NH₄-N, PFBA, and PFBS were lower, at approximately 47.9%, 44.0%, and 55.4%, respectively. In addition, COD was preferentially adsorbed before PFCs and NH₄-N, when the contact time ranged from 0 to 180 min, and the order of PFCs removal showed a positive correlation with C-F chain length. The kinetic study revealed that the removal of COD, NH₄-N, and PFCs could be better depicted and predicted by the Lagergren quasi-second order dynamic model with high correlation coefficients, which involved liquid membrane diffusion, intraparticle diffusion, and photocatalytic reactions. The saturated ZnO/AC was finally regenerated using ultrasound for 3 h and retained excellent performance, which proved it could be considered as an effective and alternative technology.

Contamination profiles and health risks of PFASs in groundwater of the Maozhou River basin

Per-and polyfluoroalkyl substances (PFASs) are a group of chemicals with a wide range of industrial and commercial applications, but little is known about the contamination of PFASs in groundwater and their linkage to surface water. Here we investigated the occurrence of PFASs in groundwater and surface water at the Maozhou River basin in order to understand their contamination profiles and potential health risks. The results showed that total PFASs concentrations ranged from 9.9 to 592.2 ng/L, 50.2-339.9 ng/L and 3.7-74.3 ng/g in groundwater, river water and sediment, respectively. The detection frequencies of C4-C8 chains (C₄-C₈) PFASs were higher than C9-C14 chains PFASs in the river and groundwater. Statistical analysis showed an obvious correlation between the major contaminants in the river and those in the groundwater, indicating the potential linkage of PFASs in the groundwater to the surface water. The wastewater indicator found in groundwater suggested domestic wastewater was only one of the source for the PFASs in the river and groundwater of Maozhou River basin. Moreover, human health risk assessment showed low risks from the PFASs to the residents by drinking groundwater.

Contamination profiles and risk assessment of per- and polyfluoroalkyl substances in groundwater in China

Per- and polyfluoroalkyl substances (PFASs) have attracted attention due to the potential risk they pose to ecosystems and human health. A total of 169 groundwater samples were collected from four representative regions in order to analyze PFASs concentrations in China. The total concentration of PFASs (∑PFASs) in groundwater ranged from 0.05 to 198.80 ng L^-1, with an average of 3.97 ng L^-1. All targeted PFASs were detected in the studied areas. The detection frequency and average concentration of perfluorooctanoic acid (PFOA) were the highest (79.29% and 1.61 ng L^-1, respectively). The contamination profiles of PFASs in each study area varied due to natural geographical conditions and human activities. According to the results of the potential source identification, the point sources of perfluorooctane sulfonate (PFOS) were mainly concentrated in Lanzhou, and the distribution of PFASs was slightly affected by atmospheric deposition in all the studied areas. The obtained concentrations of PFOA and PFOS may pose no threat to the residents due to water consumption.

Per- and polyfluoroalkyl substances in commercially available biosolid-based products: The effect of treatment processes

Per- and polyfluoroalkyl substances (PFAS) have been used in a variety of consumer and industrial products and are known to accumulate in sewage sludge due to sorption and their recalcitrant nature. Treatment processes ensure safe and high-quality biosolids by reducing the potential for adverse environmental impacts such as pathogen levels; however, they have yet to be evaluated for their impact on the fate of PFAS. The objective of this study was to compare PFAS concentrations in four commercially available biosolid-based products that received different types of treatments: heat treatment, composting, blending, and thermal hydrolysis. Seventeen perfluoroalkyl acids (PFAAs) were quantified using liquid chromatography with tandem quadrupole time-of-flight mass spectrometry followed by screening for 30 PFAA precursors. Treatment processes did not reduce PFAA loads except for blending, which served only to dilute concentrations. Several PFAA precursors were identified with 6:2 and 8:2 fluorotelomer phosphate diesters in all samples pre- and post-treatment. PRACTITIONER POINTS: Heat treatment and composting increased perfluoroalkyl acid (PFAA) concentrations. Only dilution from blending with non-PFAS material decreased PFAA concentrations. Thermal hydrolysis process had no apparent effect on PFAA concentrations. PFAS sources are a greater driver of PFAS loads in biosolid-based products than treatment processes.

Adsorption of perfluoroalkyl and polyfluoroalkyl substances (PFASs) from aqueous solution - A review

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have gained increasingly global attention in recent years. Due to their unique amphiphilic properties and stability, PFASs are recognized as highly persistent, toxic, and environmentally bioaccumulative. Among several physicochemical technologies, adsorption has been extensively used and proved to be an effective method for removing PFASs from aqueous environment. In this review article, the technical feasibility of the use of different adsorbents, such as activated carbon, ion exchange resins, minerals, molecularly imprinted polymer (MIP), carbon nanotubes (CNTs), and a wide range of potentially low-cost biosorbents, for PFASs removal from water or wastewater is critically reviewed. The evaluation and comparison of their PFASs sorption behavior in terms of kinetics and isotherms is presented. The mechanisms involved in PFASs adsorption processes, such as diffusion, electrostatic interaction, hydrophobic interaction, ion exchange and hydrogen bond, are discussed. The effects of the parameters variability on sorption process are highlighted. Based on the literature reviewed, a few recommendations for future research on PFASs adsorption are also elaborated. Capsule: The adsorption behavior and mechanisms of perfluoroalkyl and polyfluoroalkyl substances (PFASs) on various adsorbents are reviewed.

Characteristics and human inhalation exposure of ionic per- and polyfluoroalkyl substances (PFASs) in PM10 of cities around the Bohai Sea: Diurnal variation and effects of heating activity

Atmospheric PM₁₀ (particulate matter with aerodynamic diameter <10 μm) samples were collected in the cities along the Bohai Sea Rim during heating and non-heating periods, and ionic per- and polyfluoroalkyl species (PFASs) in the PM₁₀ were measured. The total concentration of ionic PFASs ranged from 21.8 to 87.0 pg/m³, and the mean concentration of ionic PFASs during the day (42.6 pg/m³) was slightly higher than that at night (35.1 pg/m³). Generally, diurnal variations in the levels of ionic PFASs were consistent with those in the PM₁₀ concentrations. Perfluorooctanoic acid (PFOA, 23.5-33.7%), perfluoropentanoic acid (PFPeA, 28.3-39.9%) and perfluorobutyric acid (PFBA, 17.1-20.1%) accounted for the dominant compositional contributions. Significant positive correlations (p < 0.05) between the main components of PFASs and O₃ implied that oxidative degradation (O₃ served as the main oxidant) in the period of non-heating may affect the short-chain PFASs. The clustering analysis of a 72-h backward trajectory indicated that cross-provincial transport contributed to ionic PFASs at the sampling sites. Compared with ingestion via daily diet, the inhalation of PM₁₀ exhibited an insignificant contribution to the estimated average daily intakes (ADIs) of PFASs by different age groups. In addition, the calculated hazard ratios (HRs) for the non-cancer respiratory risk, based on the air concentrations of PFOA and perfluorooctane sulfonate (PFOS), also manifested lower non-cancer risk through inhalation exposure. CAPSULE: The effects of heating and non-heating activity and diurnal variation on the concentrations of PFASs, dominated by PFOA, PFPeA, and PFBA in PM₁₀, were determined, and atmospheric trans-provincial input served as an important source.

Occurrence, distribution and behavior of emerging persistent organic pollutants (POPs) in a Mediterranean wetland protected area

The analysis of perfluoroalkyl substances (PFASs) and organophosphate flame retardants (PFRs) in the different environmental compartments of a characteristic coastal wetland, the Albufera Natural Park (Valencia, Spain), is required for understanding the transport, accumulation and fate of these pollutants in an area under high anthropogenic pressure. Samples included 13 wastewater treatment plant influents, 13 effluents, 12 surface water, 19 sediment samples and 10 fish individuals from the Albufera Natural Park and the surrounding area. Tris(2-chloroisopropyl) phosphate (TCIPP) and perfluorooctane sulfonate (PFOS) were at the highest concentrations in water, 330.2 ng L^-1 and 47.8 ng L^-1, respectively. In fish and sediment PFOS was also the most detected while perfluorooctanoic acid (PFOA) was in all types of water. Higher levels of target compounds (mainly PFASs) in wastewater effluents compared to influent suggested both, formation from precursors during treatment and poor removal efficiency. Mean levels of PFOS in water and fish were higher than the environmental quality standards (EQS) established by the European Union Directive 2013/39/EU. The influence of the metropolitan area of Valencia and its surrounding industrial belt could explain the significantly higher levels reported in the northern part (influenced by the Turia River).

Occurrence and partitioning behavior of perfluoroalkyl acids in wastewater effluent discharging into the Long Island Sound

Perfluoroalkyl acids (PFAAs) were measured in aqueous and suspended particulate matter (SPM) fractions in the final effluents from 12 wastewater treatment facilities located around the Connecticut shoreline. Aqueous phase concentrations ranged from 53 to 198 ng/L for ∑PFAAs with ≤7 perfluorinated carbons (CF₂) and 2-73 ng/L for >7 CF₂ PFAAs. Predominant PFAAs associated with effluent derived SPM were perfluorodecanoic acid and perflurorooctane sulfonic acid, detected in 48% and 52% of samples in concentrations ranging from <LOQ-1770 ng/g and <LOQ-2750 ng/g respectively. Based on the range of concentrations detected and the average flow of final effluent to the Long Island Sound (LIS), average total annual PFAA mass loads from wastewater treatment facilities to the LIS is estimated in the range of 70-315 kg/year, with 4-100 kg/year consisting of >7 CF₂ PFAAs. Partitioning coefficients (log K_OC) derived for effluent water and SPM phases (4.2 ± 0.3, 4.4 ± 0.4, 5.1 ± 0.2 and 5.3 ± 0.2 for PFOA, PFNA PFDA and PFUnA; 4.5 ± 0.2 and 5.2 ± 0.2 for PFOS and PFHsX respectively) were found to be of similar magnitude to aeration tank particles, though 0.5 to 2 log units greater than sludge solids and to natural system particulates including riverine SPM, estuarine SPM and sediments. Results from this study suggest that effluent derived suspended particulate matter could be an effective vector in the transport of long-chained PFAAs through wastewater treatment into receiving waters, and a potential vector to the local food chain.