Long-term trends of fluorotelomer alcohols in a wastewater treatment plant impacted by textile manufacturing industry

Embryonic exposure to 6:2 fluorotelomer alcohol mediates autism spectrum disorder-like behavior by dysfunctional microbe-gut-brain axis in mice

6:2 fluorotelomer alcohol (6:2 FTOH) is considered an emerging contaminant as a substitute for perfluoroalkyl and polyfluoroalkyl substances. Autism spectrum disorder (ASD) is a highly heterogeneous childhood neurodevelopmental disorder, the prevalence of which has been significantly increasing globally, possibly due to rising exposure to environmental pollutants. Additionally, the microbe-gut-brain axis plays a crucial role in the development of ASD. The purpose of study was to investigate the impact of embryonic 6:2 FTOH exposure on neurological development in mice and explore the potential involvement of the microbe-gut-brain. Pregnant mice were orally administered 6:2 FTOH from gestation day 8.5 until delivery, and follow-up testing was performed on day 22 post-delivery. The findings revealed that embryonic exposure to 6:2 FTOH led to ASD-like symptoms, cortical neuron apoptosis, glial cell activation, and abnormal synapse formation in mice. Furthermore, impairment of colonic barrier function, inflammatory response, and dysbiosis in gut microbiota were observed. Interestingly, supplementation with Lactobacillus rhamnosus GG during embryonic development mitigated these adverse outcomes. This study enhances our understanding of how environmental pollutants can impact neurological development in children and provides valuable insights for clinical prevention, diagnosis, and treatment strategies for non-genetic ASD.

Nexus of Soil Microbiomes, Genes, Classes of Carbon Substrates, and Biotransformation of Fluorotelomer-Based Precursors

The unpredictable biodegradation of fluorotelomer (FT)-based per- and polyfluoroalkyl substances (PFAS) causes complicated risk management of PFAS-impacted sites. Here, we have successfully used redundancy analysis to link FT-based precursor biodegradation to key microbes and genes of soil microbiomes shaped by different classes of carbon sources: alcohols (C2-C4), alkanes (C6 and C8), an aromatic compound (phenol), or a hydrocarbon surfactant (cocamidopropyl betaine [CPB]). All the enrichments defluorinated fluorotelomer alcohols (n:2 FtOH; n = 4, 6, 8) effectively and grew on 6:2 fluorotelomer sulfonate (6:2 FtS) as a sulfur source. The butanol-enriched culture showed the highest defluorination extent for FtOHs and 6:2 FtS due to the high microbial diversity and the abundance of desulfonating and defluorinating genes. The CPB-enriched culture accumulated more 5:3 fluorotelomer carboxylic acid, suggesting unique roles of Variovorax and Pseudomonas. Enhanced 6:2 FtOH defluorination was observed due to a synergism between two enrichments with different carbon source classes except for those with phenol- and CPB-enriched cultures. While the 6:2 fluorotelomer sulfonamidoalkyl betaine was not degraded, trace levels of 6:2 fluorotelomer sulfonamidoalkyl amines were detected. The identified species and genes involved in desulfonation, defluorination, and carbon source metabolism are promising biomarkers for assessing precursor degradation at the sites.

Analysis of Legacy and Novel Neutral Per- and Polyfluoroalkyl Substances in Soils from an Industrial Manufacturing Facility

Per- and polyfluoroalkyl substances (PFASs) have been detected in an array of environmental media due to their ubiquitous use in industrial and consumer products as well as potential release from fluorochemical manufacturing facilities. During their manufacture, many fluorotelomer (FT) facilities rely on neutral intermediates in polymer production including the FT-alcohols (FTOHs). These PFAS are known to transform to the terminal acids (perfluoro carboxylic acids; PFCAs) at rates that vary with environmental conditions. In the current study on soils from a FT facility, we employed gas chromatography coupled with conventional- and high-resolution mass spectrometry (GC-MS and GC-HRMS) to investigate the profile of these precursor compounds, the intermediary secondary alcohols (sFTOHs), FT-acrylates (FTAcr), and FT-acetates (FTAce) in soils around the former FT-production facility. Of these precursors, the general trend in detection intensity was [FTOHs] > [sFTOHs] > [FTAcrs], while for the FTOHs, homologue intensities generally were [12:2 FTOH] > [14:2 FTOH] > [16:2 FTOH] > [10:2 FTOH] > [18:2 FTOH] > [20:2 FTOH] > [8:2 FTOH] ∼ [6:2 FTOH]. The corresponding terminal acids were also detected in all soil samples and positively correlated with the precursor concentrations. GC-HRMS confirmed the presence of industrial manufacturing byproducts such as FT-ethers and FT-esters and aided in the tentative identification of previously unreported dimers and other compounds. The application of GC-HRMS to the measurement and identification of precursor PFAS is in its infancy, but the methodologies described here will help refine its use in tentatively identifying these compounds in the environment.

Non-target and target screening and risk assessment of per- and polyfluoroalkyl substances in textile wastewater and receiving river

Textile industry uses varieties of chemicals including per- and polyfluoroalkyl substances (PFAS). PFAS are known to be persistent and incompletely removed in wastewater treatment plants (WWTPs). So far, little is known about what types of PFAS are used in the textile industry and their potential risks. Here we investigated PFAS in two WWTPs and a receiving river of a textile industrial park in Guangxi, China, by using both target and non-target analyses over a two-year period. The target analysis identified 11 specific PFAS, while the non-target analysis revealed a list of 648 different PFAS, including both legacy and emerging substances. Notably, perfluorooctanoic acid (PFOA) was still the most prevalent compound detected. Of particular concern was the finding that the investigated WWTPs, which employs an A/O (Anaerobic/Aerobic) process, exhibited a poor removal efficiency for PFAS. The average removal rate was only 22.0 %, indicating that the current treatment processes are inadequate in effectively mitigating PFAS contamination. Correlation analysis further highlighted the potential for PFAS to be transported from WWTPs to the receiving river, revealing a significant and strong positive correlation between the PFAS in the WWTP effluent and those of the river. Perfluorooctanesulfonic acid (PFOS) and two emerging PFAS (DTXSID30240816 and DTXSID90240817) were identified to have high ecological risks in the receiving river. Notably, these two emerging PFAS are homologues, and their presence in WWTPs has been poorly reported. The findings highlight the wide use and persistence of PFAS in current textile WWTPs, indicating potential long term risks to the receiving environment.

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.

Tissue-specific distribution and bioaccumulation of perfluoroalkyl acids, isomers, alternatives, and precursors in citrus trees of contaminated fields: Implication for risk assessment

The ingestion of fruits containing perfluoroalkyl acids (PFAAs) presents potential hazards to human health. This study aimed to fill knowledge gaps concerning the tissue-specific distribution patterns and bioaccumulation behavior of PFAAs and their isomers, alternatives, and precursors (collectively as per-/polyfluoroalkyl substances, PFASs) within citrus trees growing in contaminated fields. It also assessed the potential contribution of precursor degradation to human exposure risk of PFASs. High concentrations of total target PFASs (∑PFASstarget, 92.45-7496.16 ng/g dw) and precursors measured through the total oxidizable precursor (TOP) assay (130.80-13979.21 ng/g dw) were found in citrus tree tissues, and short-chain PFASs constituted the primary components. The total PFASs concentrations followed the order of leaves > fruits > branches, bark > wood, and peel > pulp > seeds. The average contamination burden of peel (∑PFASstarget: 57.75%; precursors: 71.15%) was highest among fruit tissues. Bioaccumulation factors (BAFs) and translocation potentials of short-chain, branched, or carboxylate-based PFASs exceeded those of their relatively hydrophobic counterparts, while ether-based PFASs showed lower BAFs than similar PFAAs in above-ground tissues of citrus trees. In the risk assessment of residents consuming contaminated citruses, precursor degradation contributed approximately 36.07% to total PFASs exposure, and therefore should not be ignored.

Target and non-target analyses of neutral per- and polyfluoroalkyl substances from fluorochemical industries using GC-MS/MS and GC-TOF: Insights on their environmental fate

Novel and emerging per- and polyfluoroalkyl substances (PFAS) are a key issue of concern in global environmental studies. In this study, air, sediment, and wastewater samples were collected from areas in and/or surrounded by fluorochemical-related industrial facilities to characterize the contamination profiles of neutral and novel PFAS (n-PFAS) using a gas chromatograph-based target and non-target analyses. Fluorotelomer alcohols were predominant in the samples, accounting for 80 % of the n-PFAS, followed by fluorotelomer acrylates. Air samples collected proximate to the durable water repellent (DWR) facility had the highest concentration of n-PFAS, which was approximately two orders of magnitude higher than those found in others. Non-target analysis identified fluorotelomer iodides and fluorotelomer methacrylate in multiple matrices near DWR facilities, indicating significant contamination of n-PFAS. Levels of both C6- and C8-based PFAS reflected a shift in usage patterns from C8- to C6-based fluorochemicals. Matrix-dependent profiles of n-PFAS revealed that shorter-chain (e.g., C6) and longer-chain (>C8) PFAS were predominant in air and sediment, respectively, implying that air and sediment are mobile and secondary sources of PFAS. Untreated and treated industrial wastewater also contained n-PFAS and their transformation products. The findings shed light on our understanding of the multi-matrix distribution and transport of PFAS.

Rapid, efficient, and green analytical technique for determination of fluorotelomer alcohol in water by stir bar sorptive extraction

Fluorotelomer alcohols (FTOHs) are one of the major classes of per- and polyfluoroalkyl substances (PFAS). Due to their potential toxicity, persistence, and ubiquitous presence in the environment, some common PFAS are voluntarily phased out; while FTOHs are used as alternatives to conventional PFAS. FTOHs are precursors of perfluorocarboxylic acids (PFCAs) and therefore they are commonly detected in water matrices, which eventually indicate PFAS contamination in drinking water supplies and thus a potential source of human exposure. Even though studies have been conducted nationwide to evaluate the degree of FTOHs in the water environment, robust monitoring is lacking because of the unavailability of simple and sustainable analytical extraction and detection methods. To fill the gap, we developed and validated a simple, rapid, minimal solvent use, no clean-up, and sensitive method for the determination of FTOHs in water by stir bar sorptive extraction (SBSE) coupled with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Three commonly detected FTOHs (6:2 FTOH, 8:2 FTOH, and 10:2 FTOH) were selected as the model compounds. Factors such as extraction time, stirring speed, solvent composition, salt addition, and pH were investigated to achieve optimal extraction efficiency. This "green chemistry" based extraction provided good sensitivity and precision with low method limits of detection ranging from 2.16 ng/L to 16.7 ng/L and with an extraction recovery ranging 55%-111%. The developed method were tested on tap water, brackish water, and wastewater influent and effluent. 6:2 FTOH and 8:2 FTOH were detected in two wastewater samples at 78.0 and 34.8 ng/L, respectively. This optimized SBSE-TD-GC-MS method will be a valuable alternative to investigate FTOHs in water matrices.