Legacy and emerging poly- and perfluorochemicals in seawater and sediment from East China Sea

Regulation of terrestrial input and ocean processes on the occurrence and transport of traditional and emerging per- and polyfluoroalkyl substances in the inner shelf of the East China Sea

Coastal oceans, serving as transitional zones between land and sea, possess unique geographical features and complex hydrological conditions, functioning as regional reservoirs and crucial transport pathways for anthropogenic pollutants such as per- and polyfluoroalkyl substances (PFASs) to the open ocean. This study comprehensively investigates traditional perfluoroalkyl carboxylic and sulphonic acids (PFCAs and PFSAs) and emerging perfluoroalkyl ether carboxylic and sulfonic acids (PFECAs and PFESAs), fluorotelomer sulfonates (FTSAs) in seawater columns and surface sediments from the inner shelf of the East China Sea, by integrating hydrological and biogeochemical data. Comparable levels of traditional and emerging PFASs were observed in seawater samples, in contrast to higher concentrations of traditional PFASs in surface sediments. Waterborne PFASs exhibited a nearshore-to-offshore decreasing trend and a surface enrichment pattern in offshore waters, typically influenced by terrestrial inputs and oceanic processes. Significant terrestrial inputs for waterborne PFASs were identified, including large rivers like the Changjiang River (Yangtze) and semi-enclosed coastal bays such as Xiangshan Port and Sanmen Bay, where prolonged hydraulic retention times contribute to PFAS accumulation. The source apportionment model demonstrated that emerging fluorochemical manufacturing, textile production, and high-performance fluoropolymer materials are primary sources, consistent with PFAS releases from commercial products and industrial processes along the Changjiang River and in Xiangshan County. Hydrologically, the offshore transport barrier effect created by river plume fronts, and the vertical stratification of different water masses were significant for PFASs. Sediment inputs and resuspension also played a crucial role, with surface sediment-bottom water partitioning behavior primarily regulated by the hydrophobicity of PFASs and salting-out effects. While the overall ecological risks of PFASs were low, elevated risks associated with legacy perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and emerging hexafluoropropylene oxide dimer acid (HFPO-DA) warrant closer attention due to their accumulation in the environment. The methodologies and findings of this research provide valuable insights into PFAS cycling in coastal oceans worldwide.

Spatial heterogeneity of per- and polyfluoroalkyl substances caused by glacial melting in Tibetan Lake Nam Co due to global warming

Per- and polyfluoroalkyl substances (PFASs) in high-latitude polar regions and the Tibetan Plateau have received widespread international attention. Here, we measured 18 PFASs and 11 major isomers in the lake water, sediment, and surrounding runoff of Lake Nam Co in 2020. The concentrations of ultrashort-chain trifluoroacetic acid (TFA) and perfluoropropanoic acid (PFPrA) and major isomers of perfluoooctanoic acid (PFOA) and perfluoooctane sulfonate acid (PFOS) in water bodies in high-latitude polar regions and the Tibetan Plateau are reported for the first time. The results showed that the concentration of ∑PFASs in glacial runoff was approximately 139 % greater than that in nonglacial runoff. The concentrations of ∑PFASs in the lake water and sediment in the southern lake with multiple glacial runoff events were approximately 113 % and 108 % higher, respectively, than those in the northern lake. The concentrations of short-chain perfluorobutanoic acid (PFBA) and ultrashort-chain TFA and PFPrA, which may be indicators of ice and snow melt, exhibited significant spatial heterogeneity. Overall, the spatial heterogeneity of PFAS concentrations in the water, sediment and surrounding runoff of Lake Nam Co may be caused mainly by glacial melting.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) and nutrients from two constructed wetlands in a city of southeastern China

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large class of toxic contaminants. Nutrients are closely related to the ecological health of aquatic systems. Both have received widespread global attention. This study investigated the concentrations, compositions, and spatial distributions of PFAS and nutrients in surface water from two constructed wetlands and the nearby drinking water treatment plants (DWTPs). We explored the natural environmental factors and human activities that affect the composition and distribution of pollutants in wetlands and assessed the ability of the DWTPs to remove contaminants. Concentrations of ∑32PFAS varied from 153 to 405 ng/L. Hexafluoropropylene oxide trimer acid (HFPO-TA) was the predominant substance accounting for 45 % of ∑32PFAS concentrations. It might originate from the emissions of indirect sources of PFAS related manufacturers. The detection rate of 6:2 fluorotelomer carboxylic acid (6:2 FTCA) was 100 % with concentrations ranging from 0.915 to 19.7 ng/L 6:2 FTCA might come from the biotransformation of indirect sources in the air. Concentrations of total nitrogen (TN) and total phosphorus (TP) were from 1.47 to 3.54 mg/L, and non-detect (ND) to 0.323 mg/L, respectively. Constructed wetlands could effectively remove PFAS under nutrient stress, however, the removal of PFAS depends on the characteristics of specific compounds and their sources. The removal rates for PFAS and nutrients could be promoted through artificial dredging. But wetland bioremediation could have two opposing effects. On the one hand, plants can take up pollutants from water via roots, leading to pollutant removal and purification. On the other hand, plants may also absorb precursor intermediates from the air through leaves and release them into the water, leading to increased pollutant concentrations. Thirty-two emerging PFAS were identified by high resolution mass spectrum. The drinking water treatment process removed PFAS and nutrients below the drinking water quality standards of China, however, 9 non-target PFAS compounds were still found in tap water. These results provide case support and a theoretical basis for the pollution control and sustainable development of typical ecological wetlands used as drinking water sources.

Disruption of zebrafish sex differentiation by emerging contaminants hexafluoropropylene oxides at environmental concentrations via antagonizing androgen receptor pathways

As alternatives of perfluorooctanoic acid (PFOA), hexafluoropropylene oxide dimeric acid (HFPO-DA) and trimeric acid (HFPO-TA) have been detected increasingly in environmental media and even humans. They have been shown to exhibit reproductive toxicity to model species, but their effects on human remain unclear due to the knowledge gap in their mode of action. Herein, (anti-)androgenic effects of the two HFPOs and PFOA were investigated and underlying toxicological mechanism was explored by combining zebrafish test, cell assay and molecular docking simulation. Exposure of juvenile zebrafish to the chemicals during sex differentiation promoted feminization, with HFPO-TA acting at an environmental concentration of 1 μg/L. The chemicals inhibited proliferation of human prostate cells and transcriptional activity of human and zebrafish androgen receptors (AR), with HFPO-TA displaying the strongest potency. Molecular docking revealed that the chemicals bind to AR in a conformation similar to a known AR antagonist. Combined in vivo, in vitro and in silico results demonstrated that the chemicals disrupted sex differentiation likely by antagonizing AR-mediated pathways, and provided more evidence that HFPO-TA is not a safe alternative to PFOA.

Amino Group-Driven Adsorption of Sodium p-Perfluorous Nonenoxybenzene Sulfonate in Water by the Modified Graphene Oxide

Sodium p-perfluorous nonenoxybenzene sulfonate (OBS) is one of the key alternatives to perfluoroalkyl substances (PFASs). Its widespread tendency has increased extensive contamination in the aquatic environment. However, the present treatment technology for OBS exhibited insignificant adsorption capacity and long adsorption time. In this study, three proportions (1:5, 3:5, and 10:1) of chitosan-modified amino-driven graphene oxide (CS-GO) were innovated to strengthen the OBS adsorption capacity, compared with graphene oxide (GO) and graphene (GH). Through the characterization of SEM, BET, and FTIR, it was discovered that CS was synthetized on GO surfaces successfully with a low specific surface area. Subsequently, batch single influence factor studies on OBS removal from simulated wastewater were investigated. The optimum removal efficiency of OBS could be achieved up to 95.4% within 2 h when the adsorbent was selected as CS-GO (10:1), the dosage was 2 mg, and the pH was 3. The addition of inorganic ions could promote the adsorption efficiency of OBS. In addition, CS-GO presented the maximum adsorption energy due to additional functional groups of -NH3, and electrostatic interaction was the foremost motive for improving the adsorption efficiency of OBS. Moreover, OBS exhibited the fastest diffusion coefficient in the CS-GO-OBS solution, which is consistent with the fitting results of adsorption kinetics.

Perfluorooctane sulfonate (PFOS) induces apoptosis and autophagy by inhibition of PI3K/AKT/mTOR pathway in human granulosa cell line KGN

Perfluorooctane sulfonate (PFOS) is recognized as an environmental endocrine disruptor with widespread use in industrial manufacturing and daily life, contributing to various public health concerns. However, the precise impacts of PFOS on the ovary and its regulatory mechanisms remain unclear. This study aims to delineate the ovarian toxicity of PFOS and scrutinize its effects on apoptosis and autophagy through modulation of the PI3K/AKT/mTOR pathway in the human granulosa cell line (KGN). Cell viability, assessed via the Cell Counting Kit-8 (CCK8), revealed a dose-dependent reduction in cell viability upon PFOS exposure. Flow cytometry analysis demonstrated an elevated proportion of apoptotic cells following PFOS treatment. Western blot analyses unveiled increased expression of Bax, Cyt c, cleaved caspase-9, and LC3-II/I, coupled with decreased expression of Bcl-2 and p62. Transmission electron microscopy (TEM) observations illustrated a heightened number of autophagosomes induced by PFOS. Molecular docking investigations, in conjunction with Western blot experiments, substantiated PFOS's significant inhibition of the PI3K/AKT/mTOR signaling pathway. These findings collectively underscore that PFOS induces apoptosis and autophagy in KGN cells through modulation of the PI3K/AKT/mTOR pathway, providing experimental evidence for PFOS-induced ovarian toxicity and elucidating the underlying regulatory mechanisms in KGN cells.

Legacy and Emerging Per- and Polyfluoroalkyl Substances in a Subtropical Marine Food Web: Suspect Screening, Isomer Profile, and Identification of Analytical Interference

The ban/elimination of legacy per- and polyfluoroalkyl substances (PFASs) has led to a dramatic increase in the production and use of various emerging PFASs over the past decade. However, trophodynamics of many emerging PFASs in aquatic food webs remain poorly understood. In this study, samples of seawaters and marine organisms including 15 fish species, 21 crustacean species, and two cetacean species were collected from the northern South China Sea (SCS) to investigate the trophic biomagnification potential of legacy and emerging PFASs. Bis(trifluoromethylsulfonyl)imide was found in seawater via suspect screening (concentration up to 1.50 ng/L) but not in the biota, indicating its negligible bioaccumulation potential. A chlorinated perfluorooctane sulfonate (PFOS) analytical interfering compound was identified with a predicted formula of C14H23O5SCl6- (most abundant at m/z = 514.9373). Significant trophic magnification was observed for 22 PFASs, and the trophic magnification factors of cis- and trans-perfluoroethylcyclohexane sulfonate isomers (1.92 and 2.25, respectively) were reported for the first time. Perfluorohexanoic acid was trophic-magnified, possibly attributed to the PFAS precursor degradation. The hazard index of PFOS was close to 1, implying a potential human health risk via dietary exposure to PFASs in seafood on the premise of continuous PFAS discharge to the SCS.

Legacy and novel perfluoroalkyl substances in major economic species of invertebrates in South China Sea: Health implication from consumption

Continuously release of perfluoroalkyl substances (PFASs) would pose non-negligible impacts on environment, organisms, and human health. In present study, 18 PFASs in 7 typical economic invertebrates and their habitats were investigated from the South China Sea. The higher concentrations of PFASs in the nearshore water (6.61-15.54 ng/L) and sediment (0.82-8.84 ng/g) obviously due to frequent human activities. Long-chain PFASs have tendency to accumulate in sediment, however, short-chain PFASs dominated in biota. The acute reference dose (%ARfD) and hazard ratios (HR) of major PFASs in biota were all <100 %, and also below 1, respectively, which means that consumption of PFASs from seafood does not pose risk and threat to human health. However, it should be taken into account that the HR of PFHxA in Mimachlamys nobilis reached 0.82. Potential adverse effects toward human health induced by short-chain PFASs (such as <6 C) via invertebrate seafood consumption should be concerned.

Emerging poly- and perfluoroalkyl substances in water and sediment from Qiantang River-Hangzhou Bay

Many emerging poly- and perfluoroalkyl substances (PFASs) are being used in China, due to the gradual phase out of legacy PFASs. Occurrence and environmental behaviors of emerging PFASs in Chinese fresh water environment are still not well known. In this study, 31 PFASs, including 14 emerging PFASs, were measured in 29 pairs of water and sediment samples from Qiantang River-Hangzhou Bay, an important drinking water resource for cities in Yangtze River basin. Perfluorooctanoate was consistently the predominant legacy PFAS in water (8.8-130 ng/L) and sediment (3.7-49 ng/g dw). Twelve emerging PFASs were detected in water, with the dominance of 6:2 chlorinated polyfluoroalkyl ether sulfonates (6:2 Cl-PFAES; mean 11 ng/L, 0.79-57 ng/L) and 6:2 fluorotelomer sulfonate (6:2 FTS; 5.6 ng/L, < LOD-29 ng/L). Eleven emerging PFASs were found in sediment, and were also dominated by 6:2 Cl-PFAES (mean 4.3 ng/g dw, 0.19-16 ng/g dw) and 6:2 FTS (2.6 ng/g dw, < LOD-9.4 ng/g dw). Spatially, sampling sites closed to the surrounding cities had comparatively higher water concentrations of PFASs. Among emerging PFASs, 8:2 Cl-PFAES (3.0 ± 0.34) had the highest mean field-based log-transformed organic‑carbon normalized sediment-water partition coefficient (log K_oc), followed by 6:2 Cl-PFAES (2.9 ± 0.35) and hexafluoropropylene oxide trimer acid (2.8 ± 0.32). p-perfluorous nonenoxybenzene sulfonate (2.3 ± 0.60) and 6:2 FTS (1.9 ± 0.54) had relatively lower mean log K_oc values. To our knowledge, this is the most comprehensive study investigating the occurrence and partitioning behaviors of emerging PFASs in Qiantang River.

The novel polyfluoroalkyl benzenesulfonate OBS exposure induces cell cycle arrest and senescence of rat pituitary cell GH3 via the p53/p21/RB pathway

Sodium p-perfluorous nonenoxybenzene sulfonate (OBS), an economical alternative to perfluorooctane sulfonate (PFOS) in multiple industrial fields, is widely detected in the environment. The toxicity of OBS has received increasing attention. Pituitary cells are components of the endocrine system and act as vital regulators of homeostatic endocrine balance. However, the effects of OBS on pituitary cells remain unknown. The present study explores the effects of OBS (0.5, 5, and 50μM) on GH3 rat pituitary cells after treatment for 24, 48, and 72h. We found that OBS significantly inhibited cell proliferation in GH3 cells with remarkable senescent phenotypes, including enhanced SA-β-gal activity and expression of senescence-associated secretory phenotype (SASP)-related genes, cell cycle arrest, and upregulation of the senescence-related proteins γ-H2A.X and Bcl-2. OBS caused significant cell cycle arrest of GH3 cells at the G1-phase and concomitantly downregulated the expression of some key proteins for the G1/S transition, including cyclin D1 and cyclin E1. Consistently, the phosphorylation of retinoblastoma (RB), which plays a central role in regulating the cell cycle, was prominently reduced after OBS exposure. Furthermore, OBS notably activated the p53-p21 signalling pathway in GH3 cells, as evidenced by increased p53 and p21 expressions, enhanced p53 phosphorylation, and augmented p53 nuclear import. To our knowledge, this study is the first to reveal that OBS triggers senescence in pituitary cells via the p53-p21-RB signalling pathway. Our study demonstrates a novel toxic effect of OBS in vitro, and provides new perspectives for understanding the potential toxicity of OBS.

Spatial distribution and risk assessment of conazole fungicides in surface seawater of the East China Sea

Conazole fungicides (CFs), the common-used pesticide in agriculture distributed widely in the environment. This research analyzed the occurrence, potential sources, and risks of eight CFs in the East China Sea surface seawater in the early summer of 2020. The total CF concentration ranged from 0.30 to 6.20 ng/L, with an average value of 1.64 ± 1.24 ng/L. Fenbuconazole, hexaconazole, and triadimenol were the major CFs that comprised >96 % of the total concentration. The Yangtze River was identified as the significant source of CFs from the coastal regions to the off-shore inputs. Ocean current was the first-order factor controlling the content and distribution of CFs in the East China Sea. Although risk assessment revealed CFs posed a low or no substantial risk to ecology and human health, long-term monitoring was also encouraged. This study provided a theoretical foundation for assessing CFs' pollution levels and potential risks in the East China Sea.

Bioaccumulation and biomagnification of emerging poly- and perfluoroalkyl substances in marine organisms

Accumulating evidence has demonstrated the wide environmental presence of 6:2 chlorinated polyfluoroalkyl ether sulfonates (6:2 Cl-PFAES) and p-perfluorous nonenoxybenzene sulfonate (PFNOBS). However, data on the bioaccumulation and trophic magnification of these emerging poly- and perfluoroalkyl substances (PFASs) in subtropical marine environment is still limited. In this study, seawater (n = 17), sediment (n = 14), and marine organism (27 species; n = 177) samples were collected from East China Sea, and analyzed them for legacy and emerging PFASs. Besides perfluoroalkyl carboxylates and perfluorooctane sulfonate (PFOS), 6:2 Cl-PFAES was always among the predominant PFASs detected in seawater, sediment, and marine organism. For emerging PFASs, 6:2 Cl-PFAES (mean ± SD, 3.1 ± 0.17), 8:2 Cl-PFAES (3.3 ± 0.35), and PFNOBS (3.3 ± 0.19) had lower bioaccumulation factors (BAF) than PFOS (3.4 ± 0.22) in marine fish. In crab, PFNOBS (3.7 ± 0.33) had a lower biota-sediment accumulation factor (BSAF) than PFOS (3.9 ± 0.45). In snail, among all detected PFASs, PFNOBS (4.0 ± 0.42) had the highest mean log BSAF value. 8:2 Cl-PFAES consistently had a higher log BSAF value than 6:2 Cl-PFAES in snail and crab. Notably, these differences in BAF and BSAF are not significant. Among PFASs, 6:2 Cl-PFAES (2.3; 95 % confidence interval, CI: 1.9-2.6) displayed the highest trophic magnification factor (TMF). PFNOBS had the lowest TMF value (1.8, 95 % CI: 1.4-2.1), but which still indicates its weak biomagnification through the current marine food web. This is the first study reporting the bioaccumulation and biomagnification of PFNOBS in marine organisms, which deepens the understanding of its environmental behavior in the marine ecosystem.

The Need for Testing Isomer Profiles of Perfluoroalkyl Substances to Evaluate Treatment Processes

Many environmentally relevant poly-/perfluoroalkyl substances (PFASs) including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) exist in different isomeric (branched and linear) forms in the natural environment. The isomeric distribution of PFASs in the environment and source waters is largely controlled by the source of contamination and varying physicochemical properties imparted by their structural differences. For example, branched isomers of PFOS are relatively more reactive and less sorptive compared to the linear analogue. As a result, the removal of branched and linear PFASs during water treatment can vary, and thus the isomeric distribution in source waters can influence the overall efficiency of the treatment process. In this paper, we highlight the need to consider the isomeric distribution of PFASs in contaminated matrices while designing appropriate remediation strategies. We additionally summarize the known occurrence and variation in the physicochemical properties of PFAS isomers influencing their detection, fate, toxicokinetics, and treatment efficiency.

Developing a QSPR Model of Organic Carbon Normalized Sorption Coefficients of Perfluorinated and Polyfluoroalkyl Substances

Perfluorinated and polyfluoroalkyl substances (PFASs) are known for their long-distance migration, bioaccumulation, and toxicity. The transport of PFASs in the environment has been a source of increasing concerned. The organic carbon normalized sorption coefficient (Koc) is an important parameter from which to understand the distribution behavior of organic matter between solid and liquid phases. Currently, the theoretical prediction research on log Koc of PFASs is extremely limited. The existing models have limitations such as restricted application fields and unsatisfactory prediction results for some substances. In this study, a quantitative structure–property relationship (QSPR) model was established to predict the log Koc of PFASs, and the potential mechanism affecting the distribution of PFASs between two phases from the perspective of molecular structure was analyzed. The developed model had sufficient goodness of fit and robustness, satisfying the model application requirements. The molecular weight (MW) related to the hydrophobicity of the compound; lowest unoccupied molecular orbital energy (ELUMO) and maximum average local ionization energy on the molecular surface (ALIEmax), both related to electrostatic properties; and the dipole moment (μ), related to the polarity of the compound; are the key structural variables that affect the distribution behavior of PFASs. This study carried out a standardized modeling process, and the model dataset covered a comprehensive variety of PFASs. The model can be used to predict the log Koc of conventional and emerging PFASs effectively, filling the data gap of the log Koc of uncommon PFASs. The explanation of the mechanism of the model has proven to be of great value for understanding the distribution behavior and migration trends of PFASs between sediment/soil and water, and for estimating the potential environmental risks generated by PFASs.

Evaluated serum perfluoroalkyl acids and their relationships with the incidence of rheumatoid arthritis in the general population in Hangzhou, China

Perfluoroalkyl acids (PFAAs) are widely present in human blood, and have many toxic effects on humans. However, effects of PFAA exposure on the risk of rheumatic immune diseases are limited. In the present study, occurrence of 7 PFAAs, including perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnA), perfluorododecanoate (PFDoA), and perfluorotrdecanoate (PFTrA), were measured in serum samples from 156 healthy people (controls) and 156 rheumatoid arthritis (RA) cases living in Hangzhou, China. We also investigated the relationships among cumulative PFAA levels in serum, some immune markers, and the incidence of RA. The results showed that PFOA (6.1 and 11.8 ng/mL) had the highest mean serum concentrations, followed by PFOS (3.2 and 3.4 ng/mL) and PFDA (0.86 and 2.6 ng/mL), in both controls and RA cases. Cumulative exposure to PFOA in the study population were positively correlated with the levels of rheumatoid factors (r_s = 0.69, p < 0.01) and anti-cyclic citrullinated peptide antibody (r_s = 0.56, p < 0.05). Moreover, significant associations of PFOA concentrations with odds ratios (OR) of RA (OR = 1.998, confidence interval (CI): 1.623, 2.361, p = 0.01) were found by adjusting for various covariates. The crude and adjusted OR for RA was respective 1.385 (95% CI: 1.270, 1.510, p = 0.04) and 1.381 (95% CI: 0.972, 1.658, p = 0.06) for a unit increase in serum PFOS levels, but the adjusted results were not significant. Overall, this case-control study found that human serum PFOA concentrations were positively correlated with RF and ACPA levels.

Aberrant hepatic lipid metabolism associated with gut microbiota dysbiosis triggers hepatotoxicity of novel PFOS alternatives in adult zebrafish

Perfluorooctane sulfonate (PFOS) has been reported to induce hepatotoxicity in wildlife and humans. Novel PFOS alternatives have been widely used following restrictions on PFOS, but little is known about their potential toxicity. Here, the first comprehensive investigation on the chronic hepatotoxicity and underlying molecular mechanisms of PFOS, 6:2Cl-PFESA (F-53B), and sodium p-perfluorous nonenoxybenzene sulfonate (OBS) was carried out on adult zebrafish through a histopathological examination, biochemical measurement, and multi-omics analysis. PFOS and its alternatives caused changes in liver histopathology and liver function indices in the order of F-53B > PFOS > OBS, which was consistent with their concentration in the liver. In silico modeling and transcriptional profiles suggested that the aberrant hepatic lipid metabolism induced by F-53B and PFOS was initiated by the action on peroxisome proliferator-activated receptor γ (PPARγ), which triggered changes in downstream genes transcription and led to an imbalance between lipid synthesis and expenditure. Gut microbiome analysis provided another novel mechanistic perspective that changes in the abundance of Legionella, Ralstonia, Brevundimonas, Alphaproteobacteria, Plesiomonas, and Hyphomicrobium might link to alterations in the PPAR pathway based on their significant correlation. This study provides insight into the molecular mechanisms of hepatotoxicity induced by PFOS and its novel alternatives and highlights the need for concern about their environmental exposure risks.

Spatiotemporal distribution, partitioning behavior and flux of per- and polyfluoroalkyl substances in surface water and sediment from Poyang Lake, China

Thirty-five legacy and emerging per- and polyfluoroalkyl substances (PFAS) were analyzed in surface water and sediments collected from Poyang Lake, the largest freshwater lake in China. The ƩPFAS concentrations ranged from 23 to 1000 ng/L in water dissolved phase, 1.3-9.8 ng/L in suspended particulate matters, and 0.26-2.9 ng/g dry weight in sediments. Short-chain and emerging PFAS were predominant in surface water and sediments, rather than legacy perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Hexafluoropropylene oxide dimer/trimer acid (HFPO-DA/TA), 6:2 and 8:2 chlorinated polyfluorinated ether sulfonic acids (6:2 and 8:2 Cl-PFESAs), 6:2 fluorotelomer sulfonate (6:2 FTS), and sodium p-perfluorous nonenoxybenzene sulfonate (OBS) were detected in all samples, indicating that these emerging PFAS have been widely produced and used in this region. The high concentrations of HFPO-DA/TA, 6:2 FTS, 6:2, 8:2 Cl-PFESAs, and OBS in sediments and their higher water-sediment distribution coefficients than those of predecessors (PFOA or PFOS) suggest that lake sediments could be an important long-term sink for these emerging alternatives. The positive matrix factorization model demonstrated that food packaging and textile treatments (50%) and fluoropolymer manufacturing (26% for alternative sources and 8.2% for legacy sources) were the two major sources of PFAS in Poyang Lake. The influx and outflux of total PFAS in Poyang Lake were 9.0 and 12.8 ton/year, respectively, and the OBS flux was estimated for the first time. The results provide insights into the environmental behavior and fate of emerging PFAS in freshwater ecosystems.

Per-/polyfluoroalkyl substance concentrations in human serum and their associations with liver cancer

Per-/polyfluoroalkyl substances (PFASs) are widespread in global human blood, and have some toxic effects on liver. However, effects of PFAS exposure on human liver cancer (LC) risk are still not known. In this study, 203 LC patients and 203 controls were recruited, and their serum samples were collected between 2019 and 2021. We determined the residues of 12 PFASs in serum from all participants and quantified their association with LC incidence and tumor markers. PFOS (9.8 ng/mL) had the highest mean concentration in human serum, followed by PFOA (8.3 ng/mL) and 6:2 Cl-PFESA (3.9 ng/mL). We found that concentrations of PFOS and 6:2 Cl-PFESA in human serum were significantly correlated with the levels of alpha fetoprotein (AFP) (β_PFOS = 0.13, 95% confidence interval (CI_PFOS): 0.088, 0.17; β_{6:2 Cl-PFESA} = 0.070, CI_{6:2 Cl-PFESA}: 0.036, 0.10). A positive association of PFOS and 6:2 Cl-PFESA with odds ratios (OR) of LC (OR_PFOS = 0.609, CI_PFOS: 1.179, 4.029, P = 0.001; OR_{6:2 Cl-PFESA} = 1.844, CI_{6:2 Cl-PFESA}: 1.176, 2.512, P = 0.02) were found, after adjusting for different covariates. Moreover, serum PFOA concentrations were associated with carcinoembryonic antigen (CEA), but their correlation with the LC incidence was not statistically significant. This new finding supports the evidence for the positive associations among PFAS exposure, change of specific tumor marker, and LC risks.