A two-generation oral gavage reproduction study with potassium perfluorobutanesulfonate (K+PFBS) in Sprague Dawley rats

Hepatic transcriptomic assessment of Sprague Dawley rats in response to dietary perfluorobutane sulfonate (PFBS) ingestion

Perfluorobutane sulfonate is a short-chain PFAS that is a less toxic replacement for the rather more toxic long-chain perfluorooctane sulfonate. PFBS is widespread in the environment and has raised environmental and health concerns. The study goal was to investigate whether dietary ingestion of PFBS would induce hepatic damage. Sprague-Dawley rats were assigned to three PFBS treatment groups for 11 weeks followed by clinical markers analyses in the serum and liver. There was a significant increase in liver and body weights of PFBS rats. Total antioxidant capacity was significantly reduced in the PFBS-treated group. ALT levels increased based on concentration ingested. Close to 1000 gene transcripts were differentially expressed. Further, transmembrane transport and oxidation-reduction processes were the most up-regulated biological processes. Inflammatory genes were up-regulated in the exposed group and those associated with oxidative damage were down-regulated. In conclusion, PFBS ingestion produced mild effects in the liver of Sprague Dawley rats.

Multi-omics reveal disturbance of glucose homeostasis in pregnant rats exposed to short-chain perfluorobutanesulfonic acid

Perfluorobutanesulfonic acid (PFBS), a short-chain alternative to perfluorooctanesulfonic acid (PFOS), is widely used in various products and is increasingly present in environmental media and human bodies. Recent epidemiological findings have raised concerns about its potential adverse health effects, although the specific toxic mechanism remains unclear. This study aimed to investigate the metabolic toxicity of gestational PFBS exposure in maternal rats. Pregnant Sprague Dawley (SD) rats were randomly assigned to three groups and administered either 3% starch gel (control), 5, or 50 mg/kg bw·d PFBS. Oral glucose tolerance tests (OGTT) and lipid profiles were measured, and integrated omics analysis (transcriptomics and non-targeted metabolomics) was employed to identify changes in genes and metabolites and their relationships with metabolic phenotypes. The results revealed that rats exposed to 50 mg/kg bw·d PFBS exhibited a significant decrease in 1-h glucose levels and the area under the curve (AUC) of OGTT compared with the starch group. Transcriptomics analysis indicated significant alterations in gene expression related to cytochrome P450 exogenous metabolism, glutathione metabolism, bile acid secretion, tumor pathways, and retinol metabolism. Differentially expressed metabolites (DEMs) were enriched in pathways such as pyruvate metabolism, the glucagon signaling pathway, central carbon metabolism in cancer, and the citric acid cycle. Co-enrichment analysis and pairwise correlation analysis among genes, metabolites, and outcomes identified several differentially expressed genes (DEGs), including Gstm1, Kit, Adcy1, Gck, Ppp1r3c, Ppp1r3d, and DEMs such as fumaric acid, L-lactic acid, 4-hydroxynonenal, and acetylvalerenolic acid. These DEGs and DEMs may play a role in the modulation of glucolipid metabolic pathways. In conclusion, our results suggest that gestational exposure to PFBS may induce molecular perturbations in glucose homeostasis. These findings provide insights into the potential mechanisms contributing to the heightened risk of abnormal glucose tolerance associated with PFBS exposure.

Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies

PFASs are linked to serious health and environmental concerns. Among their widespread applications, PFASs are known to be used in food packaging and directly contribute to human exposure. However, information about PFASs in food packaging is scattered. Therefore, we systematically map the evidence on PFASs detected in migrates and extracts of food contact materials and provide an overview of available hazard and biomonitoring data. Based on the FCCmigex database, 68 PFASs have been identified in various food contact materials, including paper, plastic, and coated metal, by targeted and untargeted analyses. 87% of these PFASs belong to the perfluorocarboxylic acids and fluorotelomer-based compounds. Trends in chain length demonstrate that long-chain perfluoroalkyl acids continue to be found, despite years of global efforts to reduce the use of these substances. We utilized ToxPi to illustrate that hazard data are available for only 57% of the PFASs that have been detected in food packaging. For those PFASs for which toxicity testing has been performed, many adverse outcomes have been reported. The data and knowledge gaps presented here support international proposals to restrict PFASs as a group, including their use in food contact materials, to protect human and environmental health.

Hypoxic and temporal variation in the endocrine disrupting toxicity of perfluorobutanesulfonate in marine medaka (Oryzias melastigma)

Perfluorobutanesulfonate (PFBS) is an emerging pollutant capable of potently disrupting the sex and thyroid endocrine systems of teleosts. However, the hypoxic and temporal variation in PFBS endocrine disrupting toxicity remain largely unknown. In the present study, adult marine medaka were exposed to environmentally realistic concentrations of PFBS (0 and 10 µg/L) under normoxia or hypoxia conditions for 7 days, aiming to explore the interactive behavior between PFBS and hypoxia. In addition, PFBS singular exposure was extended till 21 days under normoxia to elucidate the time-course progression in PFBS toxicity. The results showed that hypoxia inhibited the growth and caused the suspension of egg spawn regardless of PFBS exposure. With regard to the sex endocrine system, 7-day PFBS exposure led to an acute stimulation of transcriptional profiles in females, which, subsequently, recovered after the 21-day exposure. The potency of hypoxia to disturb the sex hormones was much stronger than PFBS. A remarkable increase in estradiol concentration was noted in medaka blood after hypoxia exposure. Changes in sex endocrinology of coexposed fish were largely determined by hypoxia, which drove the formation of an estrogenic environment. PFBS further enhanced the endocrine disrupting effects of hypoxia. However, the hepatic synthesis of vitellogenin and choriogenin, two commonly used sensitive biomarkers of estrogenic activity, failed to initiate in response to the estrogen stimulus. Compared to sex endocrine system, disturbances in thyroidal axis by PFBS or hypoxia were relatively mild. Overall, the present findings will advance our toxicological understanding about PFBS pollutant under the interference of hypoxia.

Transcriptomics integrated with metabolomics reveals perfluorobutane sulfonate (PFBS) exposure effect during pregnancy and lactation on lipid metabolism in rat offspring

Emerging epidemiological evidence indicates potential associations between gestational perfluorobutane sulfonate (PFBS) exposure and adverse metabolic outcomes in offspring. However, the underlying mechanisms remain unclear. Our study aimed to investigate PFBS exposure effects during pregnancy and lactation on rat offspring lipid profiles and the possible underlying mechanisms. Although the biochemical index difference including total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), alanine amino transaminase (ALT), aspartate amino transferase (AST), and fasting blood glucose between exposed groups and the control group was not significant, transcriptome analyses showed that the differentially expressed genes (DEGs) in the 50 mg/kg/day PFBS exposure group were significantly related to protein digestion and absorption, peroxisome proliferator activated-receptor (PPAR) signaling pathway, xenobiotic metabolism by cytochrome P450, glycine, serine and threonine metabolism, β-alanine metabolism, bile secretion, unsaturated fatty acid (FA) biosynthesis, and alanine, aspartate and glutamate metabolism. Untargeted metabolomics analyses identified 17 differential metabolites in the 50 mg/kg/day PFBS exposure group. Among these, phosphatidylserine [PS (18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z))], lysoPE (18:1(11Z)/0:0), and PS (14:0/20:4(5Z,8Z,11Z,14Z)) were significantly correlated with phospholipid metabolism disorders. Correlation analysis indicated the DEGs, including FA binding protein (Fabp4), spermine oxidase (Smox), Fabp2, acyl-CoA thioesterase 5 (Acot5), sarcosine dehydrogenase (Sardh), and amine oxidase, copper-containing 3 (Aoc3) that significantly enriched in xenobiotic metabolism by cytochrome P450 and glycine, serine, and threonine metabolism signaling pathways were highly related to the differential metabolite pantetheine 4'-phosphate. Pantetheine 4'-phosphate was significantly negatively associated with non-high-density lipoprotein (non-HDL) and TC levels. Collectively, our study indicated that maternal PFBS exposure at a relatively low level could alter gene expression and metabolic molecules in lipid metabolism-related pathway series in rat offspring, although the effects on metabolic phenotypes were not significant within the limited observational period, using group-wise and trend analyses.

Novel insights into perfluorinated compound-induced hepatotoxicity: Chronic dietary restriction exacerbates the effects of PFBS on hepatic lipid metabolism in mice

Perfluorobutane sulfonates (PFBS) have garnered extensive utilization because of their distinctive physicochemical properties. The liver acts as a key target organ for toxicity within the body and is vital for regulating metabolic processes, particularly lipid metabolism. However, there is currently a significant research gap regarding the influences of PFBS on hepatic lipid metabolism, especially in individuals with different dietary statuses. Here, the objective of this research was to examine the effects of PFBS on hepatic function under different dietary conditions. The results suggested that the levels of liver injury biomarkers were significantly upregulated, e.g., transaminase (GPT, GOT), while liver lipid levels were downregulated after exposure to PFBS at concentration of 50 μg/L for 42 days. Moreover, restricted diet further intensified the adverse effects of PFBS on the liver. Metabolomics analysis identified significant alterations in lipid-related metabolites in PFBS-induced hepatotoxicity, PFBS exposure induced a decrease in lysophosphatidylethanolamine and lysophosphatidylcholine. PFBS exposure caused an increase in aldosterone and prostaglandin f2alpha under restricted diet. In PFBS treatment group, histidine metabolism, beta-alanine metabolism, and arginine biosynthesis were the main pathway for PFBS toxicity. Aldosterone-regulated sodium reabsorption as a vital factor in inducing PFBS toxicity in the RD-PFBS treatment group. The analysis of 16S rRNA sequencing revealed that exposure to PFBS resulted in imbalance of gut microbial communities. PFBS exposure induced a decrease in Akkermansia and Lactobacillus, but an increase in Enterococcus. PFBS exposure caused the abundance of Lachnospiraceae_NK4A136_group was significantly elevated under restricted diet. Additionally, disruptions in the expression of genes involved in lipid production and consumption may significantly contribute to lipid imbalance in the liver. This study underscores the importance of recognizing the harmful impact of PFBS on liver function, along with the biotoxicity of contaminant influenced by dietary habits.

Significant Variability in the Developmental Toxicity of Representative Perfluoroalkyl Acids as a Function of Chemical Speciation

Current toxicological data of perfluoroalkyl acids (PFAAs) are disparate under similar exposure scenarios. To find the cause of the conflicting data, this study examined the influence of chemical speciation on the toxicity of representative PFAAs, including perfluorooctanoic acid (PFOA), perfluorobutane carboxylic acid (PFBA), and perfluorobutanesulfonic acid (PFBS). Zebrafish embryos were acutely exposed to PFAA, PFAA salt, and a pH-negative control, after which the developmental impairment and mechanisms were explored. The results showed that PFAAs were generally more toxic than the corresponding pH control, indicating that the embryonic toxicity of PFAAs was mainly caused by the pollutants themselves. In contrast to the high toxicity of PFAAs, PFAA salts only exhibited mild hazards to zebrafish embryos. Fingerprinting the changes along the thyroidal axis demonstrated distinct modes of endocrine disruption for PFAAs and PFAA salts. Furthermore, biolayer interferometry monitoring found that PFOA and PFBS acids bound more strongly with albumin proteins than did their salts. Accordingly, the acid of PFAAs accumulated significantly higher concentrations than their salt counterparts. The present findings highlight the importance of chemical forms to the outcome of developmental toxicity, calling for the discriminative risk assessment and management of PFAAs and salts.

Toxicity of perfluorobutanesulfonate on gill functions of marine medaka (Oryzias melastigma): A time course and hypoxia co-exposure study

Perfluorobutanesulfonate (PFBS) is found in hypoxia regions. Results of previous studies have shown that hypoxia was capable of altering the inherent toxicity of PFBS. However, regarding gill functions, hypoxic influences and time course progression of toxic effects of PFBS remain unclear. In this study, with the aim to reveal the interaction behavior between PFBS and hypoxia, adult marine medaka Oryzias melastigma were exposed for 7 days to 0 or 10 μg PFBS/L under normoxic or hypoxic conditions. Subsequently, to explore the time-course transition in gill toxicity, medaka were exposed to PFBS for 21 days. The results showed that hypoxia dramatically increased the respiratory rate of medaka gill, which was further enhanced by exposure to PFBS; although exposure to PFBS under normoxic conditions for 7 days did not alter respiration, exposure to PFBS for 21 days significantly accelerated the respiration rate of female medaka. Concurrently, both hypoxia and PFBS were potent to interrupt the gene transcriptions and Na⁺, K⁺-ATPase enzymatic activity that play pivotal roles in the osmoregulation in gills of marine medaka, consequently disrupting homeostasis of major ions in blood, such as Na⁺, Cl^-, and Ca²⁺. In addition, composition and diversity of the microbiome residing on surfaces of the gill were profiled by using amplicon sequencing. Acute exposure to hypoxia for only 7 days caused a significant decrease in diversity of the bacterial community of gill whatever the presence of PFBS, while PFBS exposure for 21 days increased the diversity of gill microbial community. Principal component analysis revealed that, compared with PFBS, hypoxia was the predominant driver of gill microbiome dysbiosis. Depending on duration of exposure, a divergence was caused in the microbial community of gill. Overall, the current findings underline the interaction between hypoxia and PFBS on gill function and demonstrate the temporal variation in PFBS toxicity.

Association between maternal exposure to per- and polyfluoroalkyl substances and serum markers of liver function during pregnancy in China: A mixture-based approach

Previous studies have shown that per- and polyfluoroalkyl substances (PFAS) may have hepatotoxic effects in animals. However, epidemiological evidence in humans, especially pregnant women, is limited. This study aimed to assess the association of single and multiple PFAS exposure with serum markers of liver function in pregnant women. A total of 420 pregnant women from the Guangxi Zhuang Birth Cohort were enrolled from June 2015 to April 2019. Nine PFAS were measured in the maternal serum in early pregnancy. Data for liver function biomarkers, namely, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), total bilirubin (TBIL), direct bilirubin (DBIL), and indirect bilirubin (IBIL), were obtained from medical records. In generalized linear model (GLM), there was a positive association of perfluorooctane sulfonate (PFOS) with ALT, perfluorodecanoic acid (PFDA) and perfluorobutanesulfonic acid (PFBS) with GGT, and perfluorohexane sulfonate (PFHxS) with TBIL and IBIL. In contrast, there was a negative association of perfluoroheptanoic acid (PFHpA) with TBIL. There were inverse U-shaped relationships of PFUnA with ALT and AST and PFDA with ALT by restricted cubic spline. The weighted quantile sum (WQS) regression model revealed the positive effects of the PFAS mixture on GGT, TBIL, DBIL, and IBIL. Bayesian kernel machine regression (BKMR) analysis confirmed that the PFAS mixture was positively associated with GGT, and PFBS was the main contributor. In addition, the BKMR model showed a positive association of individual PFBS with GGT, individual PFHxS with TBIL and IBIL, and a negative association of individual PFHpA with TBIL. Our findings provide evidence of an association between individual PFAS, PFAS mixture and maternal serum markers of liver function during pregnancy. Additionally, these findings also enhance concerns over PFAS exposure on maternal liver function and PFAS monitoring in pregnancy, reducing the effect of maternal liver dysfunction on maternal and infant health.

Perfluorobutanesulfonate exposure induces metabolic disturbances in different regions of mouse gut

Perfluorobutanesulfonate (PFBS), an alternative to perfluorooctanesulfonate (PFOS), has raised many health concerns. However, PFBS toxicity in the mammalian gut remains unclear. C57BL/6 mice were exposed to 10 μg/L and 500 μg/L PFBS or 500 μg/L PFOS in their water supply for 28 days. PFBS toxicity in the ileum and colon was explored and compared to that of PFOS. Biochemical analysis showed that tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) levels increased in the ileum exposed to 10 μg/L PFBS, whereas no significant changes were observed in those levels in the colon. Catalase (CAT) activity, malondialdehyde (MDA), TNF-α, and IL-1β levels increased and glutathione (GSH) levels decreased in the ileum of the 500 μg/L-PFBS group, whereas only MDA levels increased in the colon of the 500 μg/L-PFBS group. The results showed that more severe damage occurred in the ileum than in the colon after PFBS exposure, and these align with the 500 μg/L-PFOS group exposure as well. Furthermore, metabolomic analysis revealed glutathione metabolism as a vital factor in inducing PFBS and PFOS toxicities in the ileum. Steroid hormone and amino acid metabolisms were other important factors involved in PFBS and PFOS toxicities, respectively. In the colon, GSH, pyrimidine, and glucose (especially galactose) metabolism was the main contributor to PFBS toxicity, and sulfur amino acid metabolism was the main pathway for PFOS toxicity. This study provides more evidence of the health hazards due to low-dose PFBS exposure in the mammalian gut.

Dysfunction of liver-gut axis in marine medaka exposed to hypoxia and perfluorobutanesulfonate

With objectives to explore the interactive mode on the function of liver-gut axis, adult marine medaka were exposed for 7 days to environmentally realistic concentrations of perfluorobutanesulfonate (PFBS) (0 and 10 μg/L) under normoxia or hypoxia condition. Furthermore, PFBS exposure was extended to 21 days to reveal the temporal progression in toxicity. The results showed that hypoxia exposure significantly disturbed lipid metabolism, caused oxidative damage, and induced inflammation in the livers of medaka. The composition of gut microbiota was also drastically shifted by hypoxia acute exposure. In contrast, the effect of PFBS was much milder. Hypoxia was thus the determinant of the combined toxicity. Depending on the exposure duration, a time-course recovery from PFBS innate toxicity was generally noted. Overall, the present study underlines the hypoxic and temporal variation in the dysregulation of liver-gut axis by PFBS, which is expected to support a comprehensive ecological risk assessment.

Maternal exposure to perfluorobutane sulfonate (PFBS) during pregnancy: evidence of adverse maternal and fetoplacental effects in New Zealand White (NZW) rabbits

Perfluorobutanesulfonic acid (PFBS) is a replacement for perfluorooctanesulfonic acid (PFOS) that is increasingly detected in drinking water and human serum. Higher PFBS exposure is associated with risk for preeclampsia, the leading cause of maternal and infant morbidity and mortality in the United States. This study investigated relevant maternal and fetal health outcomes after gestational exposure to PFBS in a New Zealand White rabbit model. Nulliparous female rabbits were supplied drinking water containing 0 mg/l (control), 10 mg/l (low), or 100 mg/l (high) PFBS. Maternal blood pressure, body weights, liver and kidney weights histopathology, clinical chemistry panels, and thyroid hormone levels were evaluated. Fetal endpoints evaluated at necropsy included viability, body weights, crown-rump length, and liver and kidney histopathology, whereas placenta endpoints included weight, morphology, histopathology, and full transcriptome RNA sequencing. PFBS-high dose dams exhibited significant changes in blood pressure markers, seen through increased pulse pressure and renal resistive index measures, as well as kidney histopathological changes. Fetuses from these dams showed decreased crown-rump length. Statistical analysis of placental weight via a mixed model statistical approach identified a significant interaction term between PFBS high dose and fetal sex, suggesting a sex-specific effect on placental weight. RNA sequencing identified the dysregulation of angiotensin (AGT) in PFBS high-dose placentas. These results suggest that PFBS exposure during gestation leads to adverse maternal outcomes, such as renal injury and hypertension, and fetal outcomes, including decreased growth parameters and adverse placenta function. These outcomes raise concerns about pregnant women's exposure to PFBS and pregnancy outcomes.

Boosting degradation and defluorination efficiencies of PFBS in a vacuum-ultraviolet/S(Ⅳ) process with iodide involvement

Perfluorobutane sulfonate (PFBS) is considered to be a promising alternative of perfluorooctane sulfonates (PFOS), while it is also hazardous. The UV/S (Ⅳ) system has been confirmed to be effective for PFOS removal from water, while it is inefficient for PFBS decomposition. A hybrid vacuum-ultraviolet (VUV)/S (Ⅳ)/KI process was investigated for the degradation of PFBS in aqueous solution. With KI involvement, the degradation rate of PFBS was boosted from 1.8802 μg h^-1 up to 3.5818 μg h^-1 in the VUV/S (Ⅳ) process. Alkaline conditions significantly increased the degradation efficiency of PFBS, which can be explained that S (Ⅳ) was dominated by SO₃^2- rather than HSO₃^- and H₂SO₃ in alkaline conditions. Cl^-, HCO₃^-, NO₃^-, NO₂^-, and HA would inhibit the performance of the VUV/S (Ⅳ)/KI process via various reactions. In addition, the toxicity of PFBS was significantly reduced by the VUV/S (Ⅳ)/KI process. Even in actual waters, the VUV/S (Ⅳ)/KI process also presented a satisfying performance in the degradation of PFBS.

Effects of perfluorobutane sulfonate and perfluorooctane sulfonate on lipid homeostasis in mouse liver

Perfluorobutane sulfonate (PFBS), an alternative to perfluorooctane sulfonate (PFOS), has been increasingly used in recent years. However, emerging evidence has raised concerns about the potential health risks of PFBS. Here, the toxicityof low-dose PFBS on livers was explored and compared with that of PFOS. Adult C57BL/6 mice were exposed to 10 μg/L, 500 μg/L PFBS, or 500 μg/L PFOS for 28 days through drinking water. At the phenotypic level, no liver damage was observed in the 10 μg/L PFBS group. The cell apoptosis and decrease of CAT activities were observed in the 500 μg/L PFBS group, while accumulation of lipid droplets, increase of CAT activities and TAG levels were found in the 500 μg/L PFOS group. Lipidomics analysis revealed that 138, 238, and 310 lipids were significantly changed in the 10 μg/L, 500 μg/L PFBS and 500 μg/L PFOS groups, respectively. The two PFBS-treated groups induced similar global lipid changes in a dose-dependent manner, which were distinct from PFOS. Overall, PFBS exposure induced an increase in phosphatidylcholines and sphingomyelins, but a decrease in phosphatidylinositol. PFOS exposure caused an increase in triacylglycerols. This study provides more evidence on the health hazards caused by exposure to low-dose PFBS.

Cumulative maternal and neonatal effects of combined exposure to a mixture of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) during pregnancy in the Sprague-Dawley rat

Globally, biomonitoring data demonstrate virtually all humans carry residues of multiple per- and polyfluoroalkyl substances (PFAS). Despite pervasive co-exposure, limited mixtures-based in vivo PFAS toxicity research has been conducted. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are commonly detected PFAS in human and environmental samples and both produce adverse effects in laboratory animal studies, including maternal and offspring effects when orally administered during pregnancy and lactation. To evaluate the effects of combined exposure to PFOA and PFOS, we orally exposed pregnant Sprague-Dawley rats from gestation day 8 (GD8) to postnatal day 2 (PND2) to PFOA (10-250 mg/kg/d) or PFOS (0.1-5 mg/kg/d) individually to characterize effects and dose response curve parameters, followed by a variable-ratio mixture experiment with a constant dose of PFOS (2 mg/kg/d) mixed with increasing doses of PFOA (3-80 mg/kg/d). The mixture study design was intended to: 1) shift the PFOA dose response curves for endpoints shared with PFOS, 2) allow comparison of dose addition (DA) and response addition (RA) model predictions, 3) conduct relative potency factor (RPF) analysis for multiple endpoints, and 4) avoid overt maternal toxicity. Maternal serum and liver concentrations of PFOA and PFOS were consistent between the individual chemical and mixture experiments. Combined exposure with PFOS significantly shifted the PFOA dose response curves towards effects at lower doses compared to PFOA-only exposure for multiple endpoints and these effects were well predicted by dose addition. For endpoints amenable to mixture model analyses, DA produced equivalent or better estimates of observed data than RA. All endpoints evaluated were accurately predicted by RPF and DA approaches except for maternal gestational weight gain, which produced less-than-additive results in the mixture. Data support the hypothesis of cumulative effects on shared endpoints from PFOA and PFOS co-exposure and dose additive approaches for predictive estimates of mixture effects.

Molecular and genetic analyses revealed the phytotoxicity of perfluorobutane sulfonate

Perfluorobutane sulfonate (PFBS) has oily and hydrophobic characteristics similar to those of perfluorooctane sulfonic acid (PFOS), which is an environmental organic pollutant and has gradually become the main substitute for PFOS in industry. Several studies have revealed the potential toxicity of PFBS in animals. PFBS can be taken up and accumulate in plants; however, whether and how PFBS affects plant growth remain largely unclear. A low concentration of PFBS did not affect plant growth, indicating that it had higher environmental safety than other perfluorinated compounds; however, a high concentration of PFBS (>1 mM) markedly inhibited primary root growth in Arabidopsis thaliana. Subsequently, we investigated the molecular mechanisms underlying plant growth mediated by high concentrations of PFBS. First, a genome-wide transcriptomic analysis revealed that PFBS altered the expression of genes associated with phytohormone signaling pathways. Combining physio-biochemical and genetic analyses, we next demonstrated that PFBS reduced the contents of indole-3-acetic acid (IAA) and abscisic acid (ABA), and disrupted the two signaling pathways in plants, finally inhibiting root growth. Moreover, a high concentration of PFBS also inhibited photosynthesis by comprehensively repressing the expression of genes related to the Calvin cycle and the photosynthetic apparatus. Such an understanding is helpful for elucidating the phytotoxicity of PFBS and provides a new strategy for toxicology research on organic pollutants in plants.

Young fecal transplantation modulates the visual toxicity of perfluorobutanesulfonate in aged zebrafish recipients

Perfluorobutanesulfonate (PFBS) is an emerging pollutant of potent toxicity to impair visual system. Previous studies highlighted the applicability of gut microbiota manipulation to mitigate the toxicities of PFBS. However, it remains unknown whether transplantation of whole fecal microbiota to PFBS-disturbed gut can restore the health of the recipient animals, especially for aged fish that are of high susceptibility. In the present study, aged zebrafish of 3 years old were first transplanted with feces from young counterparts and then exposed to environmentally relevant concentrations of PFBS. After exposure, toxic effects of PFBS on visual system of aged zebrafish were elucidated based on transcriptional, proteomic, biochemical, histological, and behavioral evidences. In addition, interaction between young fecal transplant and innate visual toxicity of PFBS was further explored in the aged. The results showed that PFBS singular exposure induced lipid peroxidation (by 1.9-fold) in aged male eyes, which were alleviated by young fecal transplantation. PFBS also disturbed the retinal structure of the aged, which was characterized by increases in plexiform layers, but decreases in ganglion neuron number (by 26.8% and 26.0% in males and females, respectively) and optic nerve width (by 14.1% and 12.7% in males and females, respectively). It was unexpected that young fecal transplant was very potent in re-organizing the histological assembly of aged eyes regardless of PFBS coexposure, underlining the intimate interplay between gut and retina. Proteomic profiling provided more clues about the visual toxicology mechanism of PFBS, which was found to typically interfere with synaptic neurotransmission occurring in plexiform layers. However, proteome perturbation of aged eyes by PFBS exposure was effectively shifted by the transplantation of young feces towards the control phenotype, suggesting the high ameliorative potential of young fecal transplantation along the gut-retina axis. Overall, the present study pinpoints the potent visual toxicity of PFBS in aged animals and highlights the efficacy of young fecal transplant to regulate the inherent toxicity of PFBS. Future studies are necessitated to sequence the gut microbiota and unveil the underlying interactive routes between gut microbes and visual system.

Joint toxicity mechanisms of binary emerging PFAS mixture on algae (Chlorella pyrenoidosa) at environmental concentration

Since traditional Per- and polyfluoroalkyl substances (PFAS) were banned in 2009 due to their bioaccumulation, persistence and biological toxicity, the emerging PFAS have been widely used as their substitutes and entered the aquatic environment in the form of mixtures. However, the joint toxicity mechanisms of these emerging PFAS mixtures to aquatic organisms remain largely unknown. Then, based on the testing of growth inhibition, cytotoxicity, photosynthesis and oxidative stress, and the toxicity mechanism of PFAS mixture (Perfluorobutane sulfonate and Perfluorobutane sulfonamide) to algae was explored using the Gene set enrichment analysis (GSEA). The results revealed that all three emerging PFAS treatments had a certain growth inhibitory effect on Chlorella pyrenoidosa (C. pyrenoidosa), but the toxicity of PFAS mixture was stronger than that of individual PFAS and showed a significant synergistic effect at environmental concentration. The joint toxicity mechanisms of binary PFAS mixture to C. pyrenoidosa were related to the damage of photosynthetic system, obstruction of ROS metabolism, and inhibition of DNA replication. Our findings are conductive to adding knowledge in understanding the joint toxicity mechanisms and provide a basis for assessing the environmental risk of emerging PFAS.

Young fecal transplantation mitigates the toxicity of perfluorobutanesulfonate and potently refreshes the reproductive endocrine system in aged recipients

The aging process leads to the gradual impairment of physiological functions in the elderly, making them more susceptible to the toxicity of environmental pollutants. In this study, aged zebrafish were first transplanted with the feces from young donors and subsequently exposed to perfluorobutanesulfonate (PFBS), an emerging persistent toxic pollutant. The interaction between young fecal transplant and PFBS inherent toxicity was investigated, focusing on reproductive performance and the underlying endocrine mechanism. The results showed that PFBS single exposure increased the percentage of primary oocytes in aged ovaries, implying a blockage of oogenesis. However, transplantation of young feces completely abolished the effects of PFBS and promoted oocyte growth, as inferred by the obviously lower percentage of primary oocytes, accompanied by a higher percentage of cortical-alveolar oocytes. Measurement of sex hormones found that PFBS significantly increased the blood concentration of estradiol and disrupted the balance of sex hormones in the elderly, which were, however, efficiently ameliorated by young fecal transplantation. Based on gene transcription along the hypothalamic-pituitary-gonadal axis, hierarchical clustering analysis showed similar profiles of the reproductive endocrine system between young zebrafish and their aged counterparts transplanted with young feces, implying that young fecal transplantation might refresh the endocrine system of aged recipients, regardless of PFBS exposure. The increased transcription levels of mRNAs encoding vitellogenin, activinBA, and membrane bound progestin receptors would cooperatively enhance the growth and maturation of oocytes in the ovaries of aged zebrafish receiving young fecal transplantation. Overall, the findings highlighted the potent efficacy of young fecal transplantation to improve the reproductive function of the elderly and to mitigate the endocrine disruption of an environmental pollutant. These findings are expected to broaden our understanding of the efficacy, mechanisms, and application of fecal transplantation.

Internal Relative Potency Factors for the Risk Assessment of Mixtures of Per- and Polyfluoroalkyl Substances (PFAS) in Human Biomonitoring

BACKGROUND

In human biomonitoring, blood is often used as a matrix to measure exposure to per- and polyfluoroalkyl substances (PFAS). Because the toxicokinetics of a substance (determining the steady-state blood concentration) may affect the toxic potency, the difference in toxicokinetics among PFAS has to be accounted for when blood concentrations are used in mixture risk assessment.

OBJECTIVES

This research focuses on deriving relative potency factors (RPFs) at the blood serum level. These RPFs can be applied to PFAS concentrations in human blood, thereby facilitating mixture risk assessment with primary input from human biomonitoring studies.

METHODS

Toxicokinetic models are generated for 10 PFAS to estimate the internal exposure in the male rat at the blood serum level over time. By applying dose-response modeling, these internal exposures are used to derive quantitative internal RPFs based on liver effects.

RESULTS

Internal RPFs were successfully obtained for nine PFAS. Perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), perfluorononanoic acid (PFNA), perfluorododecanoic acid (PFDoDA), perfluorooctane sulfonic acid (PFOS), and hexafluoropropylene oxide-dimer acid (HFPO-DA, or GenX) were found to be more potent than perfluorooctanoic acid (PFOA) at the blood serum level in terms of relative liver weight increase, whereas perfluorobutane sulfonic acid (PFBS) and perfluorohexane sulfonic acid (PFHxS) were found to be less potent. The practical implementation of these internal RPFs is illustrated using the National Health and Nutrition Examination Survey (NHANES) biomonitoring data of 2017-2018.

DISCUSSION

It is recommended to assess the health risk resulting from exposure to PFAS as combined, aggregate exposure to the extent feasible. https://doi.org/10.1289/EHP10009.

Perfluorooctane sulfonate (PFOS) induces several behavioural defects in Caenorhabditis elegans that can also be transferred to the next generations

Perfluorooctane sulfonate (PFOS) is a well-known global persistent organic pollutant of grave concern to ecological and human health. Toxicity of PFOS to animals and humans are well studied. Although few studies have reported the behavioral effect of PFOS on nematode Caenorhabditis elegans, it's transgenerational effects were seldom studied. Therefore, we investigated the toxicity of PFOS on several behavioral responses besides bioaccumulation and transgenerational effects in C. elegans. In contrast to the several published studies, we used lower concentrations (0.5-1000 μg/L or 0.001-2.0 μM) that are environmentally relevant and reported to occur close to the contaminated areas. The 48 h median lethal concentration of PFOS was found to be 3.15 μM (1575 μg/L). PFOS (≥0.01 μM) caused severe toxicity to locomotion, and this effect was even transferred to progeny. However, after a few generations, the defect was rectified in the progeny of single-time exposed parent nematodes. Whereas, continuous exposure at 0.001 μM PFOS, no visible defects were observed in the progeny. PFOS (≥0.01 μM) also significantly decreased the brood size in a concentration-dependent manner. Besides, lifespan was affected by the higher concentration of PFOS (≥1.0 μM). These two behavioral endpoints, lifespan and reproduction defects, became less severe in the progeny. Chemotaxis plasticity was also significantly retarded by ≥ 1.0 μM PFOS compared to the control group. Results indicate that PFOS can exert severe neurobehavioral defects that can be transferred from parents to their offspring. The findings of this study have significant implications for the risk assessment of perfluorinated substances in the environment.

Metabolomic profiles in zebrafish larvae following probiotic and perfluorobutanesulfonate coexposure

Probiotic supplements are able to attenuate the developmental toxicity of perfluorobutanesulfonate (PFBS) pollutant. However, the underlying mechanisms remain unexplored. To this end, the present study acutely exposed zebrafish larvae for 4 days to 0 and 10 mg/L of PFBS, with or without the addition of probiotic Lactobacillus rhamnosus in the rearing water. The metabolomics approach was used to reveal the combined effects of PFBS and probiotics on metabolic dynamics, based on which gene transcriptions, enzymatic activities, and behavioral endpoints were further examined. The results showed that probiotic supplements were the major driver of the metabolomic fingerprints in coexposed zebrafish larvae. The addition of probiotic bacteria significantly decreased the methylation potential whilst up-regulating the demethylation process of genomic DNA, which may globally stimulate the gene expression to improve somatic growth. Acute exposure to PFBS significantly increased the cortisol concentration in zebrafish larvae, subsequently inducing stress response and hyperactive behavior. In contrast, probiotic supplementation promoted the degradation of cortisol, thus alleviating the stressful state. Antagonistic action of probiotics against PFBS developmental toxicity was also noted regarding the locomotor behavior. In addition, gut microbiota-mediated production of secondary bile acids was remarkably enhanced by probiotic supplements regardless of PFBS exposure. Overall, the present study underlines the efficacy of probiotic bacteria to protect zebrafish larvae from the metabolic disturbances of PFBS, thereby providing more evidence to support the application of probiotics in aquaculture and fishery as an environmentally-friendly choice.

Developmental toxicity of Nafion byproduct 2 (NBP2) in the Sprague-Dawley rat with comparisons to hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX) and perfluorooctane sulfonate (PFOS)

Nafion byproduct 2 (NBP2) is a polyfluoroalkyl ether sulfonic acid that was recently detected in surface water, drinking water, and human serum samples from monitoring studies in North Carolina, USA. We orally exposed pregnant Sprague-Dawley rats to NBP2 from gestation day (GD) 14-18 (0.1-30 mg/kg/d), GD17-21, and GD8 to postnatal day (PND) 2 (0.3-30 mg/kg/d) to characterize maternal, fetal, and postnatal effects. GD14-18 exposures were also conducted with perfluorooctane sulfonate (PFOS) for comparison to NBP2, as well as data previously published for hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX). NBP2 produced stillbirth (30 mg/kg), reduced pup survival shortly after birth (10 mg/kg), and reduced pup body weight (10 mg/kg). Histopathological evaluation identified reduced glycogen stores in newborn pup livers and hepatocyte hypertrophy in maternal livers at ≥ 10 mg/kg. Exposure to NBP2 from GD14-18 reduced maternal serum total T₃ and cholesterol concentrations (30 mg/kg). Maternal, fetal, and neonatal liver gene expression was investigated using RT-qPCR pathway arrays, while maternal and fetal livers were also analyzed using TempO-Seq transcriptomic profiling. Overall, there was limited alteration of genes in maternal or F1 livers from NBP2 exposure with significant changes mostly occurring in the top dose group (30 mg/kg) associated with lipid and carbohydrate metabolism. Metabolomic profiling indicated elevated maternal bile acids for NBP2, but not HFPO-DA or PFOS, while all three reduced 3-indolepropionic acid. Maternal and fetal serum and liver NBP2 concentrations were similar to PFOS, but ∼10-30-fold greater than HFPO-DA concentrations at a given maternal oral dose. NBP2 is a developmental toxicant in the rat, producing neonatal mortality, reduced pup body weight, reduced pup liver glycogen, reduced maternal thyroid hormones, and altered maternal and offspring lipid and carbohydrate metabolism similar to other studied PFAS, with oral toxicity for pup loss that is slightly less potent than PFOS but more potent than HFPO-DA.

The Nrf2a pathway impacts zebrafish offspring development with maternal preconception exposure to perfluorobutanesulfonic acid

Since the voluntary phaseout of perfluorooctanesulfonic acid (PFOS), smaller congeners, such as perfluorobutanesulfonic acid (PFBS) have served as industrial replacements and been detected in contaminated aquifers. This study sought to examine the effects of a maternal preconception PFBS exposure on the development of eggs and healthy offspring. Adult female zebrafish received a one-week waterborne exposure of 0.08, 0.14, and 0.25 mg/L PFBS. After which, females were bred with non-exposed males and embryos collected over 5 successful breeding events. PFBS concentrations were detected in levels ranging from 99 to 253 pg/embryo in the first collection but were below the limit of quantitation by fourth and fifth clutches. Therefore, data were subsequently binned into early collection embryos in which PFBS was detected and late collections, in which PFBS was below quantitation. In the early collection, embryo 24 h survival was significantly reduced. In the late collection, embryo development was impacted with unique patterns emerging between Nrf2a wildtype and mutant larvae. Additionally, the impact of nutrient loading into the embryos was assessed through measurement of fatty acid profiles, total cholesterol, and triglyceride content. There were no clear dose-dependent effects, but again unique patterns were observed between the genotypes. Preconception PFBS exposures were found to alter egg and embryo development, which is mediated by direct toxicant loading in the eggs, nutrient loading into eggs, and the function of Nrf2a. These findings provide insight into the reproductive and developmental effects of PFBS and identify maternal preconception as a novel critical window of exposure.

Probiotic supplementation mitigates the developmental toxicity of perfluorobutanesulfonate in zebrafish larvae

Perfluorobutanesulfonate (PFBS) is an emerging pollutant of international concern, which is found to impair the early embryonic development of fishes. In the context of ubiquitous and persistent pollution, it is necessary to explore mitigatory strategies against the developmental toxicity of PFBS. In this study, zebrafish larvae were acutely exposed to 0, 1, 3.3 and 10 mg/L of PFBS till 168 h post-fertilization (hpf), during which probiotic Lactobacillus rhamnosus bacteria were administered via the exposure media. After the singular or combined exposure, interaction between PFBS and probiotics on the growth of zebrafish larvae was measured. PFBS exposure significantly decreased the larval body weight, weight gain and specific growth rate, while probiotic supplementation efficiently inhibited the growth retardation caused by PFBS. Furthermore, PFBS and probiotic combinations remarkably activated the antioxidant capacity to timely scavenge the reactive oxidative species and protect the larvae from lipid peroxidation. Biochemical assay and fluorescent staining verified that PFBS exposure significantly promoted the production of bile acids, which were further enhanced by the probiotics. In coexposed zebrafish larvae, up-regulation of peroxisome proliferator-activated receptor (PPARb) would enhance the β-oxidation of fatty acids to meet the energy demand from larval growth, subsequently decreasing fatty acid concentrations. In addition, probiotic supplements masked the dysbiosis of PFBS and potently shaped the gut microbiota, which closely modulated the production of bile acids. Overall, the present findings underline the beneficial effects of probiotics to protect the developing larvae from the aquatic toxicities of PFBS, thus highlighting the potential application values of probiotic recipe in aquaculture and ecological reservation.

Probiotic intervention mitigates the metabolic disturbances of perfluorobutanesulfonate along the gut-liver axis of zebrafish

Probiotic supplementation is effective to modulate the metabolic disorders caused by perfluorobutanesulfonate (PFBS). However, the underlying mechanisms remain unclear. To this end, the present study exposed adult zebrafish to PFBS (0 and 10 μg/L), probiotics, or their binary combinations for 40 days. After the exposure, the nutritional stores, intestinal organization, and metabolic activities along the gut-liver axis were investigated. The results showed that PFBS exposure decreased the nutrient reserves significantly, especially the lipid content, which was alleviated by the probiotic administration. Intestinal mucus secretion was promoted remarkably in the presence of the probiotic, which enhanced epithelial protection against PFBS damage. Metagenomic analysis showed that PFBS alone induced gut microbial dysbiosis, which was efficiently antagonized by the probiotic bacteria. Intestinal metabolomic profiling revealed that ferroptosis occurred because of the unrestricted lipid peroxidation following PFBS exposure. However, probiotic administration prevented the ferroptotic symptoms induced by PFBS, further highlighting the beneficial effects of the probiotic on the host. In PFBS-exposed livers, high levels of bile acid metabolites (e.g., taurochenodeoxycholic acid) accumulated, implying the induction of cholestasis. Notably, probiotic addition recovered the metabolomic homeostasis under PFBS stress, probably resulting from the activation of detoxification pathways based on the pentose and glucuronate interconversion. Overall, the present study provides systematic evidence of the antagonistic interaction between PFBS and the probiotic regarding the metabolic activities along the microbe, gut and liver axis, highlighting the application values of probiotic recipe in aquaculture industry and ecological reservation.

Rapid Removal of Perfluoroalkanesulfonates from Water by β-Cyclodextrin Covalent Organic Frameworks

Adsorption is an effective method for the removal of perfluoroalkanesulfonates (PFSAs) from water, and the limitation of the adsorption rate of existing adsorbents motivates efforts to develop novel adsorbents. Here, we developed four β-cyclodextrin covalent organic frameworks (β-CD-COFs) with a rapid removal rate and high adsorption capacity for four PFSAs in water including perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS), perfluorohexanesulfonate (PFHxS), and chlorinated polyfluorinated ether sulfonate (F53B). All β-CD-COFs exhibited extremely fast adsorption (adsorption equilibrium <2 min) for PFSAs with high adsorption capacities (0.33-1.51 mmol/g), which were significantly better than those of traditional resins and activated carbons, probably due to the ordered pores of β-CD-COFs and the electron-deficient cavity β-CD. Density functional theory (DFT) calculations also showed that PFSAs could be captured in the β-CD cavity through strong interactions with a high binding energy. The novel β-CD-COFs were highly selective to PFSAs in simulated wastewater impacted by aqueous film-forming foams, and they could also rapidly remove them from an actual chrome plating wastewater within 2 min. Additionally, the β-CD-COFs could be regenerated by methanol with relatively good reusability in four cycles, further highlighting their application potential as PFAS adsorbents in water or wastewater.

Deoxyfluorination of alcohols with aryl fluorosulfonates

Aryl fluorosulfonates are developed as a deoxyfluorinating reagent in the transformation of primary and secondary alcohols into the corresponding alkyl fluorides. These reagents feature easy availability, low-cost, high stability and high efficiency. Diverse functionalities including aldehyde, ketone, ester, halogen, nitro, alkene, and alkyne are well tolerated under mild reaction conditions.

Antagonistic interaction between perfluorobutanesulfonate and probiotic on lipid and glucose metabolisms in the liver of zebrafish

Perfluorobutanesulfonate (PFBS) and probiotic bacteria can interact to induce hepatic hypertrophy. However, the molecular events occurring in the hypertrophic liver are still unknown. Therefore, we performed this follow-up study using adult zebrafish that were exposed for 40 days to 0 and 10 μg/L PFBS, with or without dietary supplementation of probiotic Lactobacillus rhamnosus. After PFBS or/and probiotic exposures, proteome perturbation, histological pathogenesis and glucose metabolism were investigated in the livers. Proteomic analysis showed potent intervention of PFBS or/and probiotic with hepatic functions. PFBS single exposure caused marked disturbances in lipid metabolisms, which may underlie the severe vacuolization in male liver. The addition of probiotic alleviated the lipid metabolic disorders of PFBS. Furthermore, probiotic supplementation enhanced ATP energy production using glucose in mitochondrial respiratory chain of male fish. However, PFBS alone caused remarkable increase in blood glucose level (by 2.5-fold relative to the control), underlining the onset of hyperglycemia symptom. In contrast, the liver of male fish from the coexposure group functioned appropriately, which immediately increased insulin levels by 2.2-fold to reduce the glucose accumulation in blood. In female liver, PFBS alone significantly decreased the blood glucagon concentration by 2.9-fold. The deficiency of glucagon hormone consequently contributed to the accumulation of glycogen (3.2-fold) therein. Vigorous antagonistic interaction between PFBS and probiotic was noted with respect to glucose metabolism, which restored ATP, glucose, glycogen and glucagon to the control levels. Overall, the present study finds that probiotic L. rhamnosus is efficient to mitigate the metabolic disorders of PFBS on lipid and glucose, highlighting the potential values of probiotic bacteria to protect the aquatic ecosystem.

Probiotic Lactobacillus rhamnosus modulates the impacts of perfluorobutanesulfonate on oocyte developmental rhythm of zebrafish

Potent interaction between probiotic bacteria and perfluorobutanesulfonate (PFBS), an aquatic pollutant of emerging concern, was previously reported on reproduction of zebrafish. However, the underlying mechanism is largely unexplored. In this regard, the present study continued to focus on the interactive modes between probiotics and PFBS. Adult zebrafish were exposed for 28 days to 0 and 10 μg/L PFBS with or without dietary supplementation of probiotic Lactobacillus rhamnosus. With the relevance to fecundity outcome, a suite of reproductive indices at transcriptional, hormonal, proteomic and histological levels of biological organization were measured herein. The fecundity monitoring results showed that probiotic additive shifted the impacts of PFBS on egg spawn, gradually approaching the control level. Based on ovary histological observation, oocyte growth was significantly promoted by probiotics or/and PFBS exposures, while the presence of probiotic bacteria partially antagonized the effects of PFBS on oocyte growth. The combination of probiotics and PFBS increased the concentration of maturation inducing hormones in ovary. Despite the enhanced hormonal signals, gene transcriptions of ovarian local auto/paracrine factors were consistently decreased in all exposure groups, suggesting the blocked transition from oocyte growth phase toward oocyte maturation phase. Ovary proteomic analysis found that PFBS exposure with or without probiotic bacteria mainly affected the RNA metabolic processes, although the addition of probiotics exerted extra influences on amino acid metabolism. Overall, the present study provided more mechanistic evidence about the interactive behavior between probiotic bacteria and PFBS pollutant. Feed additive of probiotic bacteria modulated the impacts of PFBS on egg production rhythm through oocyte growth and maturation phases.

Acute Toxicity and Transgenerational Effects of Perfluorobutane Sulfonate on Caenorhabditis elegans

Perfluorobutane sulfonate (PFBS), due to its increasing use as an alternative to perfluooctane sulfonate (PFOS), is widely detected in humans and the environment, necessitating the evaluation of its potential ecotoxicological risk. We assessed the toxicity and bioaccumulation potential of PFBS in Caenorhabditis elegans, using lethality, locomotion, reproduction, life span, growth, and chemotactic behavior as the effect parameters. In addition, a total of 6 generations of exposed parent animals were monitored for locomotion, brood, and life span behaviors. Life span and brood size were significantly reduced in parent nematodes (P0) following exposure to ≥0.1 mM PFBS, but these negative effects did not transfer to the progeny. Although there was no remarkable effect on reproduction and life span in parent worms exposed to ≤0.01 mM PFBS, multigenerational exposure at 0.0005 mM significantly affected the F4 and F5 progeny. Furthermore, 0.01 to 2.0 mM of PFBS substantially retarded the locomotion behavior of P0 worms. At higher concentrations such as 1.0 mM, this negative effect on locomotion was transferred to the next generation (F1) but later recovered from F2 progeny onward. Our findings demonstrate for the first time that chronic exposure to PFBS at higher concentrations can cause behavioral toxicity and could be transferred to the progeny. These findings have significant implications for the environmental risk assessment of PFBS. Environ Toxicol Chem 2021;40:1973-1982. © 2021 SETAC.

Per- and polyfluoroalkyl substances (PFAS) in livestock and game species: A review

Per- and polyfluoroalkyl substances (PFAS) are synthetic, organic chemicals that resist environmental breakdown. The properties that made PFAS into an industrial success also led to their persistence and bioaccumulation. As PFAS were widely used for many decades their presence is evident globally, and their persistence and potential for toxicity create concern for human, animal and environmental health. Following the precautionary principle, a reduction in human exposure is generally recommended. The most significant source of human exposure to PFAS is dietary intake (food and water) with additional exposure via dust. As PFAS concentrations have been more frequently studied in aquatic food sources, there is less understanding of exposure via terrestrial animals. To further define human exposure via animal products, it is necessary to determine PFAS concentrations and persistence in terrestrial livestock and game species. Studies assessing ambient concentrations of PFAS have noted that, aside from point sources of contamination, there is generally low input of PFAS into terrestrial agricultural food chains. However, livestock and game species may be exposed to PFAS via contaminated water, soil, substrate, air or food, and the contribution of these exposures to PFAS concentrations in food products is less well studied. This review focuses on perfluoroalkyl substances (PFAAs) and compiles information from terrestrial livestock and game species as a source of dietary exposure in humans, and discusses toxicokinetics and health effects in animals, while identifying future focus areas. Publications describing the transfer of PFAAs to farmed and hunted animals are scarce, and demonstrate large variability in distribution and elimination. We outline several relatively small, short-term studies in cattle, sheep, pigs and poultry. While negative effects have not been noted, the poultry investigations were the only studies to explicitly assess health effects. Comparative information is presented on PFAA concentrations in livestock products and edible tissues of game animals.

Interaction between probiotic additive and perfluorobutanesulfonate pollutant on offspring growth and health after parental exposure using zebrafish

Perfluorobutanesulfonate (PFBS) pollutant and probiotic bacteria can interact to affect the reproductive outcomes of zebrafish. However, it is still unexplored how the growth and health of offspring are modulated by the combination of PFBS and probiotic. In the present study, adult zebrafish were exposed to 0 and 10 μg/L PFBS for 40 days, with or without dietary supplementation of probiotic Lactobacillus rhamnosus. After parental exposure, the development, growth and viability of offspring larvae were examined, with the integration of molecular clues across proteome fingerprint, growth hormone/insulin-like growth factor (GH/IGF) axis, calcium homeostasis, hypothalamic-pituitary-adrenal (HPA) axis and nutrient metabolism. Parental probiotic supplementation significantly increased the body weight and body length of offspring larvae. Despite the spiking of PFBS, larvae from the combined exposure group still had longer body length. RNA processing and ribosomal assembly pathways may underlie the enhancement of offspring growth by probiotic bacteria. However, the presence of PFBS remarkably increased the concentrations of cortisol hormone in offspring larvae as means to cope with the xenobiotic stress, which required more energy production. As evidenced by the proteomic analysis, the addition of probiotic bacteria likely alleviated the energy metabolism disorders of PFBS, thus allocating more energy for the larval offspring growth from the combined group. It was noteworthy that multiple molecular disturbances caused by PFBS were antagonized by probiotic additive. Overall, the present study elucidated the intergenerational interaction between PFBS and probiotic on offspring growth and health after parental exposure.

Suggestions for Improving the Characterization of Risk from Exposures to Per and Polyfluorinated Alkyl Substances

Many state and federal environmental and health agencies have developed risk-based criteria for assessing the risk of adverse health effects of per- and polyfluorinated alkyl substances (PFAS) exposure to humans and the environment. However, the criteria that have been developed vary; drinking water criteria developed for perfluorooctanoic acid, for example, can vary by up to 750 fold. This is due to differences and variability in the data and information used, study/endpoint selection, assumptions and magnitude of uncertainty factors used in the absence and extrapolation of critical effect data, differences in underlying approaches to addressing exposure within criteria development, and/or policy decisions on levels of acceptable risk. We have critically evaluated the methods used to develop these criteria while focusing on derivation and application of drinking water criteria and discuss a range of improvements to risk-characterization practice recently presented at a Focused Topic Meeting on PFAS conducted by the Society of Environmental Toxicology and Chemistry in Durham, North Carolina, USA, 12 to 15 August 2019. We propose methods that consider maximizing the use of disparate data streams, seeking patterns, and proposing biologically based approaches to evidence integration toward informed criteria development. Environ Toxicol Chem 2021;40:883-898. © 2020 SETAC.

Suspect and Nontarget Screening Revealed Class-Specific Temporal Trends (2000-2017) of Poly- and Perfluoroalkyl Substances in St. Lawrence Beluga Whales

The global use of >3000 per- and polyfluoroalkyl substances (PFASs) has given rise to chemical regulatory action. However, limited information exists regarding current and historical emissions for the majority of PFASs under currently implemented regulations. This study employed suspect and nontarget screening to examine the temporal trends of legacy and unregulated PFASs in liver of the endangered beluga whale (Delphinapterus leucas) population from the St. Lawrence Estuary in Canada collected from 2000 to 2017. A suite of 54 PFASs were tentatively identified, and were grouped into nine structurally distinct classes. Single-hydrogenated perfluoro carboxylic acids (H-PFCAs), single-hydrogenated sulfonamides (H-Sulfonamides), as well as other select sulfonamides were detected for the first time in wildlife. Greater concentrations of the majority of PFASs were determined in newborns and juveniles than in adults, suggesting effective placental and lactational transfer of PFASs. Legacy per- and polyfluoroalkyl acids and perfluorooctane sulfonamide in beluga whale liver were found to significantly decrease in concentration between 2000 and 2017, while unregulated short-chain PFAS alternatives, H-PFCAs, and odd-chain FTCAs were found to increase over time. The implementation of suspect and nontarget screening revealed class-specific temporal trends of PFASs in SLE beluga whales, and supported continuous emissions of unregulated PFASs into the environment.

Perfluorooctanesulfonic acid (PFOS) and perfluorobutanesulfonic acid (PFBS) impaired reproduction and altered offspring physiological functions in Caenorhabditis elegans

Perfluorobutanesulfonic acid (PFBS), a shorter chain Per- and polyfluoroalkyl substances (PFASs) cognate of perfluorooctanesulfonic acid (PFOS), has been used as replacement for the toxic surfactant PFOS. However, emerging evidences suggest safety concerns for PFBS and its effect on reproductive health is still understudied. Therefore, the current work aimed to investigate the effect of PFBS, in comparison to PFOS, on reproductive health using Caenorhabditis elegans as an in vivo animal model. PFOS (≥10 μM) and PFBS (≥1000 μM) significantly impaired the reproduction capacity of C. elegans, represented as reduced brood size (total egg number) and progeny number (hatched offspring number), without affecting the hatchability. Additionally, the preconception exposure of PFOS and PFBS significantly altered the embryonic nutrient loading and composition, which further led to abnormalities in growth rate, body size and locomotive activity in F1 offspring. Though the effective exposure concentration of PFBS was approximately 100 times higher than PFOS, the internal concentration of PFBS was lower than that of PFOS to produce the similar effects of PFOS. In conclusion, PFOS and PFBS significantly impaired the reproductive capacities in C. elegans and the preconception exposure of these two compounds can lead to offspring physiological dysfunctions.

Binary exposure to hypoxia and perfluorobutane sulfonate disturbs sensory perception and chromatin topography in marine medaka embryos

Perfluorobutane sulfonate (PFBS), an environmental pollutant of emerging concern, is previously shown to dynamically interact with hypoxia on aquatic developmental toxicities. However, the molecular mechanisms underlying the interaction remain unknown. In this follow-up study, marine medaka embryos were exposed to 0 and 3.3 mg/L of PFBS under normoxia (6.9 mg/L) or hypoxia (1.7 mg/L) condition till 15 days post-fertilization. High-throughput transcriptomic sequencing was employed to filter differentially expressed genes and provide mechanistic insight into interactive action between hypoxia and PFBS. The results showed that hypoxia alone and the coexposure paradigm were similarly potent to modify transcriptional profiles, with the majority of genes significantly down-regulated. In contrast, transcriptional toxicity of PFBS was relatively milder. Functional annotation analyses found that hypoxia and coexposure groups mainly impacted phototransduction signaling by decreasing the transcriptions of cyclic nucleotide-gated (CNG) cation channels and retinol transport genes. However, this study demonstrated the first toxicological evidence that toxic effects of PFBS targeted the perception of chemical stimulus through olfactory and gustatory receptors. The addition of PFBS moderately exacerbated the toxic actions of hypoxia, which largely shaped the transcriptional pattern of coexposure group. In addition, gene interactive networks were constructed for hypoxia and coexposure groups, underlining the increased chromatin deacetylation and methylation to epigenetically repress genome-wide transcriptional initiation. Overall, PFBS and hypoxia interact to interrupt the embryonic development of sensory systems, which may compromise the individual fitness and survival, especially during early life stages when precocious perception of food and escape from predators are essential.

Probiotic modulation of perfluorobutanesulfonate toxicity in zebrafish: Disturbances in retinoid metabolism and visual physiology

Perfluorobutanesulfonate (PFBS), an aquatic pollutant of emerging concern, is found to disturb gut microbiota, retinoid metabolism and visual signaling in teleosts, while probiotic supplementation can shape gut microbial community to improve retinoid absorption. However, it remains unknown whether probiotic bacteria can modulate the toxicities of PFBS on retinoid metabolism and visual physiology. In the present study, adult zebrafish were exposed for 28 days to 0, 10 and 100 μg/L PFBS, with or without dietary administration of probiotic Lactobacillus rhamnosus. Interaction between PFBS and probiotic was examined regarding retinoid dynamics (intestine, liver and eye) and visual stimuli transmission. PFBS single exposures remarkably inhibited the absorption of retinyl ester in female intestines, which were, however, restored by probiotic to normal status. Although coexposure scenarios markedly increased the hepatic storage of retinyl ester in females, mobilization of retinol was reduced in livers by single or combined exposures regardless of sex. In the eyes, transport and catalytic conversion of retinol to retinal and retinoic acid were interrupted by PFBS alone, which were efficiently antagonized by probiotic presumably through an indirect action. In response to the availability of retinal chromophore, transcriptions of opsins and arrestin genes were altered adaptively to control visual perception and termination. Neurotransmission across retina circuitry was changed accordingly, centering on epinephrine and norepinephrine. In summary, the present study found the efficient modulation of probiotic on retinoid metabolic disorders of PFBS pollution, which subsequently impacted visual signaling. A future work is warranted to provide mechanistic clues in retinoid interaction.

Dietary administration of probiotic Lactobacillus rhamnosus modulates the neurological toxicities of perfluorobutanesulfonate in zebrafish

Perfluorobutanesulfonate (PFBS), an aquatic pollutant of emerging concern, is found to disturb the neural signaling along gut-brain axis, whereas probiotic additives have been applied to improve neuroendocrine function of teleosts. Both PFBS and probiotics can commonly target nervous system. However, whether and how probiotic bacteria can modulate the neurotoxicities of PFBS remain not explored. It is thus necessary to elucidate the probiotic modulation of PFBS neurotoxicity, which can provide implications to the application of probiotic bacteria in aquaculture industry. In the present study, adult zebrafish were exposed to 0, 10 and 100 μg/L PFBS with or without dietary administration of probiotic Lactobacillus rhamnosus. Interaction between PFBS and probiotic along gut-brain axis was examined, covering three dominant pathways (i.e., neurotransmission, immune response and hypothalamic-pituitary-adrenal (HPA) axis). The results showed that, compared to the single effects, PFBS and probiotic coexposure significantly altered the acetylcholinesterase activity and neurotransmitter profiles in gut and brain of zebrafish, with mild effects on neuronal integrity. Neurotransmitters closely correlated reciprocally in intestines, which, however, was distinct from the correlation profile in brains. In addition, PFBS and probiotic were combined to impact brain health through absorption of bacterial lipopolysaccharides and production of inflammatory cytokines. Relative to neurotransmission and immune signaling, HPA axis was not involved in the neurotoxicological interaction between PFBS and probiotic. Furthermore, it needs to point out that interactive modes between PFBS and probiotic varied a lot, depending on exposure concentrations, sex and toxic indices. Overall, the present study provided the first evidence that probiotic supplement could dynamically modulate the neurotoxicities of PFBS in teleost.

Parental exposure to perfluorobutane sulfonate disturbs the transfer of maternal transcripts and offspring embryonic development in zebrafish

Parental exposure to perfluorobutane sulfonate (PFBS), an aquatic pollutant of emerging concern, is previously found to impair the embryonic development of offspring. However, the impairing mechanisms remain to clarify. In the present study, adult zebrafish were exposed to 0, 10 and 100 μg/L PFBS for 28 d, after which disturbances in maternal transcript transfer and offspring embryogenesis were investigated. Prior to zygotic genome activation, high-throughput transcriptomic sequencing revealed that parental PFBS exposure significantly altered the transcript profile of maternal origin in offspring eggs, while toxic actions varied as a function of PFBS concentrations. In offspring eggs derived from 10 μg/L exposure group, differential transcripts were mainly associated with the histone-DNA interaction of nucleosome, which would modify the compacted chromatin configuration and accessibility of transcriptional factors to DNA sequences. In this regard, the timing of zygotic genome activation was presumably disrupted. Parental exposure to 100 μg/L PFBS primarily interrupted the maternal transfer of adherens junction transcripts, which was supposed to dysregulate the cell-cell adhesion during early embryo formation. Development and growth of offspring embryos were significantly compromised by parental PFBS exposure, as exemplified by higher mortality, delayed hatching, slower heart rate, reduced body weight and neurobehavioral disorders. Overall, the present study presented the first toxicological evidence about the disturbances of PFBS in maternal transcript transfer, although the inherent linkage between maternal transcript modifications and offspring development defects still needs future works to construct.

Risk to human health related to the presence of perfluoroalkyl substances in food

The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluoroalkyl substances (PFASs) in food. Based on several similar effects in animals, toxicokinetics and observed concentrations in human blood, the CONTAM Panel decided to perform the assessment for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS. These made up half of the lower bound (LB) exposure to those PFASs with available occurrence data, the remaining contribution being primarily from PFASs with short half-lives. Equal potencies were assumed for the four PFASs included in the assessment. The mean LB exposure in adolescents and adult age groups ranged from 3 to 22, the 95th percentile from 9 to 70 ng/kg body weight (bw) per week. Toddlers and 'other children' showed a twofold higher exposure. Upper bound exposure was 4- to 49-fold higher than LB levels, but the latter were considered more reliable. 'Fish meat', 'Fruit and fruit products' and 'Eggs and egg products' contributed most to the exposure. Based on available studies in animals and humans, effects on the immune system were considered the most critical for the risk assessment. From a human study, a lowest BMDL 10 of 17.5 ng/mL for the sum of the four PFASs in serum was identified for 1-year-old children. Using PBPK modelling, this serum level of 17.5 ng/mL in children was estimated to correspond to long-term maternal exposure of 0.63 ng/kg bw per day. Since accumulation over time is important, a tolerable weekly intake (TWI) of 4.4 ng/kg bw per week was established. This TWI also protects against other potential adverse effects observed in humans. Based on the estimated LB exposure, but also reported serum levels, the CONTAM Panel concluded that parts of the European population exceed this TWI, which is of concern.

Scientific Basis for Managing PFAS as a Chemical Class

This commentary presents a scientific basis for managing as one chemical class the thousands of chemicals known as PFAS (per- and polyfluoroalkyl substances). The class includes perfluoroalkyl acids, perfluoroalkylether acids, and their precursors; fluoropolymers and perfluoropolyethers; and other PFAS. The basis for the class approach is presented in relation to their physicochemical, environmental, and toxicological properties. Specifically, the high persistence, accumulation potential, and/or hazards (known and potential) of PFAS studied to date warrant treating all PFAS as a single class. Examples are provided of how some PFAS are being regulated and how some businesses are avoiding all PFAS in their products and purchasing decisions. We conclude with options for how governments and industry can apply the class-based approach, emphasizing the importance of eliminating non-essential uses of PFAS, and further developing safer alternatives and methods to remove existing PFAS from the environment.

Association between Prenatal Exposure to PFAS and Fetal Sex Hormones: Are the Short-Chain PFAS Safer?

Epidemiologic evidence regarding the effects of in utero exposure to per- and polyfluoroalkyl substances (PFAS), particularly short-chain PFAS, on fetal reproductive hormones is limited and inconsistent. This study aimed to assess the relationship between maternal PFAS exposure and fetal reproductive hormones. A total of 752 mother-infant pairs who were recruited in the Shanghai Birth Cohort Study between 2013 and 2016 were selected. We quantified 10 PFAS, including two short-chain PFAS congeners (perfluorobutanesulfonate, PFBS and perfluoroheptanoic acid, PFHpA), in maternal blood plasma in early pregnancy. Dehydroepiandrosterone sulfate (DHEA-S), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and total testosterone (TT) were measured in the umbilical cord blood using chemiluminescence kits. Free androgen index (FAI) was calculated by TT divided by SHBG. Multiple linear regression found that one ln-unit increase in maternal PFBS was associated with decreases in FSH (-0.159; 95% CI: -0.290, -0.029), LH (-0.113; 95% CI: -0.221, -0.004), and FAI (-0.009; 95% CI: -0.017, -0.001). In addition, PFHpA showed negative associations with LH (-0.154; 95% CI: -0.297, -0.011) and FAI (-0.008; 95% CI: -0.014, -0.002). When PFAS were analyzed in quartiles, significant negative associations were observed between PFBS and FSH, and between PFHpA and FAI. Overall, prenatal exposure to PFBS and PFHpA was associated with the disturbance of fetal gonadotropins as well as free androgen level in this prospective cohort, suggesting that the reproductive toxicity of short-chain PFAS may not be neglected.

Probiotic Modulation of Lipid Metabolism Disorders Caused by Perfluorobutanesulfonate Pollution in Zebrafish

To determine whether and how probiotic supplement can alter gut microbiota dysbiosis and lipid metabolism disorders caused by perfluorobutanesulfonate (PFBS), the present study exposed adult zebrafish to 0, 10, and 100 μg/L PFBS for 28 days, with or without dietary administration of probiotic Lactobacillus rhamnosus. Regarding intestinal health and gut microbiota, probiotic supplement altered the innate toxicities of PFBS, depending on exposure concentration and the sex of the fish. Lactobacillus genus correlated positively (P < 0.001; r > 0.5) with other beneficial bacteria in the gut microbiota, thereby indirectly regulating host metabolic activities. In female fish, the PFBS and probiotic combination enhanced fatty acid synthesis and β-oxidation, but mitigated the accumulation of cholesterol in the blood compared with PFBS single exposure, highlighting the benefits of the probiotic to host health. In male zebrafish, probiotic administration antagonized the PFBS-induced disturbances of bile acid metabolism, presumably via farnesoid X receptor signaling. However, coexposure to PFBS and probiotic caused significant accumulation of triglyceride in male livers (2.6-fold relative to the control), implying the induction of hepatic steatosis. Overall, the present study underlined the potential of probiotics to modulate gut microbial dysbiosis and lipid metabolism disorders caused by PFBS exposure, which could provide implications to the application of probiotics in aquaculture.

Interaction between hypoxia and perfluorobutane sulfonate on developmental toxicity and endocrine disruption in marine medaka embryos

The co-occurrence of hypoxia and xenobiotics is extremely common in natural environments, highlighting the necessity to elicit their interaction on aquatic toxicities. In the present study, marine medaka embryos were exposed to various concentrations (nominal 0, 1, 3.3 and 10 mg/L) of perfluorobutane sulfonate (PFBS), an environmental pollutant of emerging concern, under either normoxia (6.9 mg/L) or hypoxia (1.7 mg/L) condition. After acute exposure till 15 days post-fertilization, single or combined toxicities of PFBS and hypoxia on embryonic development (e.g., mortality, hatching and heartbeat) and endocrine systems were investigated. Sex and thyroid hormones were measured by enzyme-linked immunosorbent assay. Transcriptional changes of endocrine genes were determined by quantitative real-time PCR assays. Co-exposure to 10 mg/L PFBS and hypoxia caused a further reduction in survival rate and heart beat compared to single exposure. PFBS induced a precocious hatching, while no larvae hatched under hypoxia condition. By disturbing the balance of sex hormones, either PFBS or hypoxia single exposure produced an anti-estrogenic activity in medaka larvae. However, PFBS and hypoxia combinations reversed to estrogenic activity in co-exposed larvae. Variation in disrupting pattern may be attributed to the interactive effects on steroidogenic pathway involving diverse cytochrome P450 enzymes. Regarding thyroid system, PFBS exposure caused detriments of multiple processes along thyroidal axis (e.g., feedback regulation, synthesis and transport of thyroid hormones, receptor-mediated signaling and thyroid gland development), while hypoxia potently impaired the development and function of thyroid gland. Combinations of PFBS and hypoxia interacted to dysregulate the function of thyroid endocrine system. In summary, the present study revealed the dynamic interaction of PFBS pollutant and hypoxia on aquatic developmental toxicities and endocrine disruption. Considering the frequent co-occurrence of xenobiotics and hypoxia, current results would be beneficial to improve our understanding about their interactive mechanisms and provide baseline evidences for accurate ecological risk evaluation.

Exposure of adult mice to perfluorobutanesulfonate impacts ovarian functions through hypothyroxinemia leading to down-regulation of Akt-mTOR signaling

Perfluorobutanesulfonate (PFBS), a short-chain perfluoroalkyl substance, is used in many industrial products. Preliminary evidence suggests that exposure to PFBS may increase the risk of infertility. The aim of this study was to investigate the influence of PFBS on ovarian function. Herein, we show that exposure of adult female mice to PFBS (200 mg/kg/day) (PFBS-mice) caused a decrease in the levels of serum total triiodothyronine and thyroxine, which depended on the activation of peroxisome proliferator-activated receptor α (PPARα). The numbers of secondary, early antral and antral follicles were reduced in PFBS-mice with an increase in the atretic follicles, and these changes were recovered by the replacement of L-thyroxinein or the treatment with PPARα antagonist GW6471. PFBS-induced hypothyroxinemia led to a decrease in the levels of Akt, mTOR and p70S6K phosphorylation in ovarian granular cells and cumulus cells, which suppressed the proliferation of these cells and enhanced autophagic death of granular cells and cumulus cells. The levels of serum estradiol and progesterone were reduced in PFBS-mice with a low expression of the steroidogenic genes Star and P450scc in ovarian tissues, which were sensitive to the replacement of L-thyroxinein or the blockade of PPARα. The results indicate that exposure to PFBS (≥200 mg/kg/day) through reducing thyroid hormones causes down-regulation of Akt-mTOR signaling in granular cells and cumulus cells, leading to the deficits in the development of follicles and the biosynthesis of ovarian hormones.

Parental Exposure to Perfluorobutanesulfonate Impairs Offspring Development through Inheritance of Paternal Methylome

Perfluorobutanesulfonate (PFBS), an environmental pollutant of emerging concern, significantly impairs offspring development and overall health after parental exposure. However, the true inducer of offspring developmental defects among the complexity of parental influences remains unknown. In the present study, marine medaka (Oryzias melastigma) were exposed to environmentally realistic concentrations of PFBS (0, 1, 3, and 10 μg/L) for an entire life cycle. By mixing and mating control and exposed medaka (male or female), a crossbreeding strategy was employed to produce offspring eggs from various crossbreeds, with the aim of differentiating the maternal and paternal influences. Measurements of swimming performance in larval offspring showed that larvae of exposed male parents swam hyperactively in comparison to the control larvae. Contrasting trends in PFBS transfer and maternal factor transfer (e.g., proteins and lipids) to that of swimming behavior eliminated these two factors as major inducers of offspring developmental impairment. Inheritance of the exposed paternal methylome marks in offspring may be partially responsible for abnormal swimming behavior, although different toxic mechanisms may be involved depending on the exposure concentration. Overall, these findings suggest that inheritance of epigenetic modifications implicates a long-lasting threat of PFBS to the fitness and sustainability of fish populations.

Perfluorobutanesulfonate Exposure Skews Sex Ratio in Fish and Transgenerationally Impairs Reproduction

Perfluorobutanesulfonate (PFBS) is increasingly polluting aquatic environments due to worldwide manufacturing and application. However, toxicological knowledge regarding PFBS exposure remains scarce. Here, we showed that PFBS life-cycle exposure at environmentally realistic concentrations (0, 1.0, 2.9, and 9.5 μg/L) skewed the sex ratio in fish toward male dominance, while reproductive functions of female fish were greatly impaired, as characterized by extremely small ovaries, blocked oocyte development, and decreased egg production. Endocrine disruption through the hypothalamus-pituitary-gonad axis was induced by PFBS exposure, showing antiestrogenic activity in females but estrogenic activity in males. PFBS was found to gradually accumulate in F0 adults during continuous exposure but can be rapidly eliminated when depurated in clean water. Parental exposure also transferred PFBS pollutant to F1 offspring eggs. Although no trace of PFBS was detected in F1 adults and F2 eggs, adverse effects from parental exposure persisted in F1 and F2 offspring. These transgenerational effects implicate PFBS as an ongoing threat to the fitness and sustainability of fish populations. The dramatic impairment of fish reproduction highlights the urgency of re-evaluations of the ecological and evolutionary consequences of PFBS exposure.