Partitioning Behavior of Bisphenol Alternatives BPS and BPAF Compared to BPA

Prenatal exposure to bisphenol AF causes toxicities in liver, spleen, and kidney tissues of SD rats

As a replacement for bisphenol A (BPA), bisphenol AF (BPAF) showed stronger maternal transfer and higher fetal accumulation than BPA. Therefore, concerns should be raised about the health risks of maternal exposure to BPAF during gestation on the offspring. In this study, SD rats were exposed to BPAF (0, 50, and 100 mg/kg/day) during gestation to investigate the bioaccumulation and adverse effects in liver, spleen, and kidney tissues of the offspring at weaning period. Bioaccumulation of BPAF in these tissues with concentrations ranging from 1.56 ng/mg (in spleen of males) to 55.44 ng/mg (in liver of females) led to adverse effects at different biological levels, including increased relative weights of spleen and kidneys, histopathological damage in liver, spleen, and kidney, organ functional damage in liver, spleen, and kidney, upregulated expression of genes related to lipid metabolism (in liver), oxidative stress response (in kidney), immunity and inflammatory (in spleen). Furthermore, dysregulated metabolomics was identified in spleen, with 217 differential metabolites screened and 9 KEGG pathways significantly enriched. This study provides a comprehensive insight into the systemic toxicities of prenatal exposure to BPAF in SD rats. Given the broad applications and widespread occurrence of BPAF, its safety should be re-considered.

Photochemical degradation of bisphenol S and its tetrahalogenated derivatives in water

Bisphenol S (BPS), a widely used plasticizer, is known to have potential endocrine disrupting effects to organisms. Its tetrahalogenated derivatives, tetrachlorobisphenol S (TCBPS) and tetrabromobisphenol S (TBBPS), are flame retardants exhibiting high neurodevelopmental toxicity and cytotoxicity. Halogen substitution has been shown to significantly affect the optical and photochemical properties of organic compounds. In this study, we conducted a comparative investigation into the photochemical behaviors of BPS, TCBPS, and TBBPS in aqueous solutions under both laboratory UV and natural sunlight irradiation. Spectroscopic titration results indicated that the pKa of TCBPS (4.16) and TBBPS (4.13) are approximately 3.7 units smaller than that of BPS (7.85), indicating that the halogenated derivatives are mainly present as the phenolate anions under circumneutral conditions. The halogen substituents also cause a significant bathochromic shift in the absorption spectra of TCBPS and TBBPS compared to BPS, leading to the enhanced absorption of sunlight. Meanwhile, TCBPS and TBBPS showed higher quantum yields than BPS, attributed to the "heavy atom" effect of halogen substituents. GCSOLAR modeling predicted half-lives for BPS, TCBPS, and TBBPS in surface water in Nanjing (32°2'7.3''N, 118°50'21''E) under noon sunlight in clear mid-autumn days as 810.2, 3.4, and 0.7 min, respectively. Toxicity evaluation suggest potential ecological risks of BPS/TCBPS/TBBPS and their photoproducts to aquatic organisms. Our findings highlight direct photolysis as an important mechanism accounting for the attenuation of tetrahalogenated bisphenols in both sunlit surface waters and UV based water treatment processes.engineered (e.g., UV disinfection) and natural aquatic environments (e.g., surface fresh waters).

Distribution and source analysis of soil toxic organic compounds of coal-electricity production base in arid and semi-arid region of China

The presence and distribution of toxic organic compounds in soil pose significant challenges. Whether their distributional characteristics are more complex, especially in arid and semi-arid regions with harsh climatic conditions? This study analyzed the composition, classification, spatial distribution, and sources of 123 toxic organic compounds in 56 soil samples of coal-electricity production base. Those compounds were classified into 11 categories, mainly pesticides (41 compounds), organic synthesis intermediates (31 compounds), and drugs (23 compounds). Seventeen of those compounds were detected over the rate of 30 %, with 13 of them being under the Toxic Substances Control Act (TSCA) inventory. The primary sources of toxic organic compounds were determined using Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF), including the degradation of pesticide residues (22.03 %), emissions of plastic pellets (16.64 %), industrial waste emissions (12.80 %), emissions from livestock (12.74 %), plastic films (11.22 %) and coal-to-liquid projects (10.78 %). This research underscores the widespread presence of toxic organic compounds in soil, highlighting their origins and distribution patterns, which are essential for developing targeted environmental management strategies in arid and semi-arid regions.

Utility of a modified o-DGT passive sampler for measurement of bisphenol analogues in freshwater and coastal waters

Bisphenol analogues (BPs) are commonly found in riverine and coastal waters. However, the lack of a reliable and robust passive sampling method has hindered our ability to monitor these compounds in aquatic systems. The study developed a novel organic-diffusive gradients in thin film (o-DGT) sampler based on stainless steel mesh membrane, polyacrylamide diffusive gel, and hydrophilic-lipophilic balance (HLB) binding gel. This innovative design tackled issues of filter membrane sorption in traditional o-DGT devices and potential gel damage in membrane-less o-DGT devices, showing promising application prospects. The mass accumulation of 15 target BPs was linear over 10 days in both freshwater (r2 ≥ 0.92) and seawater (r2 ≥ 0.94), with no saturation observed. The diffusion coefficients (D) through polyacrylamide diffusive gels ranged from 4.04 × 10-6 to 5.77 × 10-6 cm2 s-1 in freshwater and from 1.74 × 10-6 to 4.69 × 10-6 cm2 s-1 in seawater for the target BPs (except for bisphenol PH) at 22 °C. The D values of the target BPs in seawater were lower than those in freshwater due to the high salinity in seawater (35 ‰). The o-DGT samplers demonstrated good integrity in field applications. The total concentrations of the eight detected BPs ranged from 9.2 to 323 ng L-1, which was consistent with the measurements obtained by grab sampling. Among all BPs, bisphenol S, bisphenol F, and bisphenol A were consistently detected at all sites using both sampling methods. The concentrations of some novel BPs in coastal water measured by grab sampling were comparable to those measured in rivers, suggesting the need to strengthen pollution control of BPs in coastal areas. These results indicate that the o-DGT passive sampling method developed in the present study can be effectively used for monitoring BPs in freshwater and coastal environments.

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

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

Fate and transformation of uniformly 14C-ring-labeled bisphenol S in different aerobic soils

Bisphenol S (BPS), being structurally similar to bisphenol A (BPA), has been widely used as an alternative to BPA in industrial applications. However, in-depth studies on the environmental behavior and fate of BPS in various soils have been rarely reported. Here, 14C-labeled BPS was used to investigate its mineralization, bound residues (BRs) formation and extractable residues (ERs) in three soils for 64 days. Significant differences were found in the dissipation rates of BPS in three soils with different pH values. The dissipation of BPS followed pseudo first-order kinetics with half-lives (T1/2) of 15.2 ± 0.1 d, 27.0 ± 0.2 d, 180.4 ± 5.3 d, and 280.5 ± 3.3 d in the alkaline soil (fluvo-aquic soil, FS), the neutral soil (cinnamon soil, CS), the acidic soil (red soil, RS), and sterilized cinnamon soil (CS-S), respectively. The mineralization and BRs formation contributed the most to the dissipation of BPS in soil. BPS was persistent in acidic soil, and may pose a significant threat to plants grown in acidic soils. Additionally, soil microorganisms played a key role in BPS degradation, and the organic matter content might be a major factor that promotes the adsorption and degradation of BPS in soils. Two transformed products, P-hydroxybenzenesulfonic acid and methylated BPS were identified in soils. This study provides new insights into the fate of BPS in various soils, which will be useful for risk assessments of BPS in soil.

Congener-specific uptake and accumulation of bisphenols in edible plants: Binding to prediction of bioaccumulation by attention mechanism multi-layer perceptron machine learning model

Plant accumulation of phenolic contaminants from agricultural soils can cause human health risks via the food chain. However, experimental and predictive information for plant uptake and accumulation of bisphenol congeners is lacking. In this study, the uptake, translocation, and accumulation of five bisphenols (BPs) in carrot and lettuce plants were investigated through hydroponic culture (duration of 168 h) and soil culture (duration of 42 days) systems. The results suggested a higher bioconcentration factor (BCF) of bisphenol AF (BPAF) in plants than that of the other four BPs. A positive correlation was found between the log BCF and the log Kow of BPs (R2carrot = 0.987, R2lettuce = 0.801, P < 0.05), while the log (translocation factor) exhibited a negative correlation with the log Kow (R2carrot = 0.957, R2lettuce = 0.960, P < 0.05). The results of molecular docking revealed that the lower binding energy of BPAF with glycosyltransferase, glutathione S-transferase, and cytochrome P450 (-4.34, -4.05, and -3.52 kcal/mol) would be responsible for its higher accumulation in plants. Based on the experimental data, an attention mechanism multi-layer perceptron (AM-MLP) model was developed to predict the BCF of eight untested BPs by machine learning, suggesting the relatively high BCF of bisphenol BP, bisphenol PH, and bisphenol TMC (BCFcarrot = 1.37, 1.50, 1.03; BCFlettuce = 1.02, 0.98, 0.67). The prediction of BCF for ever-increasing varieties of BPs by machine learning would reduce repetitive experimental tests and save resources, providing scientific guidance for the production and application of BPs from the perspective of priority pollutants.

Transport of bisphenol A, bisphenol S, and three bisphenol F isomers in saturated soils

With the limitation of the use of bisphenol A (BPA), the production of its substitutes, bisphenol S (BPS), and bisphenol F (4,4'-BPF) is increasing. Understanding the fate and transport of BPA and its substitutes in porous media can help reduce their risk of contaminating soil and groundwater systems. In this study, column and batch adsorption experiments were performed with 14C-labeled bisphenol analogs and combined with mathematical models to investigate the interaction of BPA, BPS, 4,4'-BPF, 2,2'-BPF, and 2,4'-BPF with four standard soils with different soil organic matter (SOM) contents. The results show that the transport capacity of BPS and 4,4'-BPF in the saturated soils is significantly stronger than that of BPA. Meanwhile, the mobility of the three isomers of bisphenol F exhibits variability in saturated soils with high SOM content. The two-site nonequilibrium sorption model was applied to simulate and interpret column experimental data, and model simulations described the interactions between the bisphenol analogs and soil very well. The fitting results underscore SOM's role in providing dynamic adsorption sites for bisphenol analogs. Hydrophobicity primarily accounts for the disparity in adsorption affinity between BPA, BPS, 4,4'-BPF, and soil, whereas hydrogen bonding forces may predominantly influence the differential adsorption affinity between 4,4'-BPF and its isomers and soil. The results of this study indicate that BPS and three isomers of BPF, as alternatives to BPA, have higher mobility in saturated soils and may pose a substantial risk to groundwater quality. This study enhances our understanding of bisphenol analogs' behavior in natural soils, facilitating an assessment of their environmental implications, particularly regarding groundwater contamination.

Transcriptomics-based analysis of sex-differentiated mechanisms of hepatotoxicity in zebrafish after long-term exposure to bisphenol AF

Bisphenol AF (BPAF) is an emerging endocrine-disrupting chemical (EDC) prevalent in the environment as one of the main substitutes for bisphenol A. Sex-specific effects of EDCs have been commonly reported and closely linked to sexually dimorphic patterns of hormone metabolism and related gene expression during different exposure windows, but our understanding of these mechanisms is still limited. Here, following 28-day exposure of adult zebrafish to an environmentally relevant concentration of BPAF at 10 μg/L, the global transcriptional networks applying RNA sequencing (RNA-seq) and Ingenuity Pathway Analysis (IPA) were respectively investigated in the male and female fish liver, connecting the sex-dependent toxicity of the long-term exposure of BPAF to molecular responses. As a result, more differentially expressed genes (DEGs) were detected in males (811) than in females (195), and spermatogenesis was the most enriched Gene Ontology (GO) functional classification in males, while circadian regulation of gene expression was the most enriched GO term in females. The expression levels of selected DEGs were routinely verified using qRT-PCR, which showed consistent alterations with the transcriptional changes in RNA-seq data. The causal network analysis by IPA suggested that the adverse outcomes of BPAF in males including liver damage, apoptosis, inflammation of organ, and liver carcinoma, associated with the regulation of several key DEGs detected in RNA-seq, could be linked to the activation of upstream regulatory molecules ifnα, yap1, and ptger2; while, the inhibition of upstream regulators hif1α, ifng, and igf1, leading to the down-regulated expression of several key DEGs, might be involved in BPAF's effects in females. Furthermore, BPAF exposure altered hepatic histological structure and inhibited antioxidant capability in both male and female livers. Overall, this study revealed different regulation networks involved in the sex-dependent effects of BPAF on the fish liver, and these detected DEGs upon BPAF exposure might be used as potential biomarkers for further assessing sex-specific hepatotoxicity following environmental EDC exposure.

Fulvic acid enhanced peroxymonosulfate activation over Co-Fe binary metals for efficient degradation of emerging bisphenols

Bisphenol F (BPF) and bisphenol S (BPS) are emerging bisphenols, which have become the main substitutes for bisphenol A (BPA) in industrial production and are also considered as new environmental pollution challenges. Thus, the necessity for an effective approach to remove BPF and BPS is essential. In this study, fulvic acid (FA) was used to modify Co-Fe binary metals (CFO) for peroxymonosulfate (PMS) activation. The characterization results demonstrated that CFO changed significantly in morphology after compounding with FA, with smaller particle size and 5.6 times larger specific surface area, greatly increasing the active sites of catalyst; Moreover, humic acid-like compounds increased the surface functional groups of CFO, especially phenolic hydroxyl, which could effectively prolong the PMS activation. The concentration of all reactive species, such as SO₄•^-, •OH, O₂•^-, and ¹O₂ increased in FA@CFO/PMS system. As a result, the degradation efficiency of CFO for both BPF and BPS was significantly improved after compounding FA, which also had a wide range of pH applications. The degradation pathways of both BPF and BPS were proposed based on liquid chromatography-mass spectrometry (LC-MS) analysis and the density functional theory (DFT) calculations. Our findings are expected to provide new strategies and methods for remediation of environmental pollution caused by emerging bisphenols.

Life history traits of low-toxicity alternative bisphenol S on Daphnia magna with short breeding cycles: A multigenerational study

Due to relatively lower toxicity, bisphenol S (BPS) has become an alternative to previously used bisphenol A. Nevertheless, the occurrence of BPS and its ecological impact have recently attracted increasing attentions because the toxicology effect of BPS with life cycle or multigenerational exposure on aquatic organisms remains questionable. Herein, Daphnia magna (D. magna) multigenerational bioassays spanning four generations (F0-F3) and single-generation recovery (F1 and F3) in clean water were used to investigate the ecotoxicology of variable chronic BPS exposure. For both assays, four kinds of life-history traits (i.e., survival, reproduction, growth and ecological behavior) were examined for each generation. After an 18-day exposure under concentration of 200 μg/L, the survival rate of D. magna was less than 15 % for the F2 generation, whereas all died for the F3 generation. With continuous exposure of four generations of D. magna at environmentally relevant concentrations of BPS (2 μg/L), inhibition of growth and development, prolonged sexual maturity, decreased offspring production and decreased swimming activity were observed for the F3 generation. In particular, it is difficult for D. magna to return to its normal level through a single-generation recovery in clean water in terms of reproductive function, ecological behavior and population health. Hence, multi-generational exposure to low concentrations of BPS can have adverse effects on population health of aquatic organisms with short breeding cycles, highlighting the necessity to assess the ecotoxicology of chronic BPS exposure for public health.

Degradation of Bisphonel AF (BPAF) by zero-valent iron activated persulfate: Kinetics, mechanisms, theoretical calculations, and effect of co-existing chloride

The removal of Bisphonel AF (BPAF) by zero-valent iron activated persulfate (Fe⁰/PS) system was systematically evaluated in this work. 30.0 μM BPAF was removed by 94.4% in 60 min of treatment under optimal conditions of pH = 3.0 and [PS] = [Fe⁰] = 3.0 mM. Cl^- significantly accelerated the removal of BPAF, resulting from accelerated Fe²⁺ release and reactive chlorine species (RCS) formation. Liquid chromatography-time-of-flight-mass spectrometry identified thirteen degradation products, and bond breaking, coupling reactions, hydroxylation and sulfate addition were considered as the major transformation pathways. When Cl^- was present, six new chlorinated byproducts were also generated. Based on density functional theory (DFT) calculations, the occurrence of radical addition reactions was verified and the preferential reaction channels were determined. Significantly BPAF degradation products were less toxic, according to toxicity assessment by the ECOSAR program. Moreover, a high removal efficiency of BPAF (>90%) was also obtained in the three actual water matrixes. The present work demonstrates the feasibility of Fe⁰/PS system for treating BPAF, which could also provide new insights into the influence of coexisting Cl^- on the environmental fate of organic pollutants in sulfate radicals based advanced oxidation processes.

Hydroxy-Containing Covalent Organic Framework Combined with Nickel Ferrite as a Platform for the Recognition and Capture of Bisphenols

A hydroxy-containing covalent organic framework (COF) was successfully obtained via a simple nitrogen-purge synthetic procedure for the first time. The COF favored a serrated AA-stacking arrangement, which enhanced the stability compared with common AA or AB arrangements. To validate the potential of the COF in environmental applications, we decorated the COF onto NiFe₂O₄ and used the NiFe₂O₄@COF nanocomposite for magnetic solid-phase extraction of trace bisphenols (BPs). The parameters affecting extraction efficiencies were systematically optimized. Under the optimum extraction conditions, calibration plots showed good linearity (5.0-1.0 × 10³ ng mL^-1) for six BPs, and limits of detection varied from 0.14 to 0.73 ng mL^-1. Molecular polarity indexes and molecular dynamics simulations revealed why the COF could efficiently recognize and capture BPs. An adsorption mechanism related to the interaction between BP clusters and the COF was discovered. Ecotoxicological assessment of BPs further unraveled the significance of the developed method for the timely tracking of the concentration, distribution, and migration of BPs in environmental media.

Adverse (geno)toxic effects of bisphenol A and its analogues in hepatic 3D cell model

Bisphenol A (BPA) is one of the most widely used and versatile chemical compounds in polymer additives and epoxy resins for manufacturing a range of products for human applications. It is known as endocrine disruptor, however, there is growing evidence that it is genotoxic. Because of its adverse effects, the European Union has restricted its use to protect human health and the environment. As a result, the industry has begun developing BPA analogues, but there are not yet sufficient toxicity data to claim that they are safe. We investigated the adverse toxic effects of BPA and its analogues (BPS, BPAP, BPAF, BPFL, and BPC) with emphasis on their cytotoxic and genotoxic activities after short (24-h) and prolonged (96-h) exposure in in vitro hepatic three-dimensional cell model developed from HepG2 cells. The results showed that BPFL and BPC (formed by an additional ring system) were the most cytotoxic analogues that affected cell viability, spheroid surface area and morphology, cell proliferation, and apoptotic cell death. BPA, BPAP, and BPAF induced DNA double-strand break formation (γH2AX assay), whereas BPAF and BPC increased the percentage of p-H3-positive cells, indicating their aneugenic activity. All BPs induced DNA single-strand break formation (comet assay), with BPAP (≥0.1 μM) being the most effective and BPA and BPC the least effective (≥1 μM) under conditions applied. The results indicate that not all of the analogues studied are safer alternatives to BPA and thus more in-depth research is urgently needed to adequately evaluate the risks of BPA analogues and assess their safety for humans.

Effects of BPZ, BPC, BPF, and BPS Exposure on Adult Zebrafish (Danio rerio): Accumulation, Oxidative Stress, and Gene Expression

As substitutes for bisphenol A (BPA), bisphenol analogs (BPs) have been found to cause endocrine disorders and induce toxic effects. The objective of this study was to evaluate the bioaccumulation and subacute toxicity of bisphenol Z (BPZ), bisphenol C (BPC), bisphenol F (BPF), and bisphenol S (BPS) to zebrafish. Five-month-old zebrafish were exposed to 1/100 LC₅₀, 1/50 LC₅₀, and 1/10 LC₅₀ of BPZ, BPC, BPF, and BPS for 13 days, respectively. Bioaccumulation, oxidative stress, and related mRNA expression in zebrafish tissues were measured on days 1, 7, and 13. After exposure, the four kinds of BPs all resulted in the accumulation of concentration and lipid peroxidation in zebrafish tissues to varying degrees. BPZ and BPC had the highest bioaccumulation level and had the greatest influence on malonic dialdehyde (MDA). In addition, the enzyme activities of superoxide dismutase (SOD), peroxidase (POD), glutathione peroxidase (GSH-PX), and the content of glutathione (GSH) in zebrafish tissues were also affected at different levels. However, the enzyme activities of SOD and POD were inactivated in zebrafish exposed to a high concentration of BPC. Further studies showed that BPs exposure down-regulated the transcription level of sod but up-regulated the relative expression levels of cat and gpx. The mRNA relative expression level of erα was not significantly changed, while the mRNA relative expression level of erβ₁ was significantly down-regulated except under BPS exposure. These results indicate that BPZ, BPC, and BPF significantly affect the expression level of the estrogen receptor (ER) in zebrafish tissues. Overall, the results suggest that exposure to waterborne BPs can cause severe oxidative stress and tissue damage in adult zebrafish that is not sufficient to kill them after 13 days of waterborne exposure. The toxicity of BPs to organisms, therefore, should be further analyzed and evaluated.

Bisphenol S degradation in soil and the dynamics of microbial community associated with degradation

Bisphenol S (BPS) has been widely applied as a replacement for BPA in industrial application, leading to the frequent detection in the environment. However, its impact on soil microbial communities has not been well reported. Here, effects of BPS exposure on soil microbial communities in the presence of polystyrene (PS) microplastics were revealed. Rapid degradation of BPS occurred with a degradation rate of up to 98.9 ± 0.001 % at 32 d. The presence of BPS reduced the diversity of soil microbial communities, and changed community structures. After BPS treatment, Proteobacteria, and its members Methylobacillus, Rhodobacteraceae and Mesorhizobium became dominant, and were considered as potential biomarkers indicating BPS contamination. Co-occurrence network analysis revealed the increased relationships of certain groups of microbes after BPS treatment. The resultant low stability and resilience towards environment disturbance of microbial community networks implied the biotoxicity of BPS towards soil ecosystems. The degradation and biotoxicity of BPS (p > 0.05) in soil was not affected by the presence of PS. Our findings showed that exposure to BPS could reshape soil microbial communities and impair the robustness of microbial co-occurrence networks.

Phytotoxicity and accumulation of BPS to Pistia stratiotes under the influence of microplastics

Bisphenol S (BPS) is a contaminant of emerging concern, its exposure and phytotoxicity towards plants, however, is scarce. This study aimed at revealing the BPS translocation in plants and phytotoxicity in the presence of Polystyrene (PS) microplastics. Results found that BPS and PS showed no effect on plant growth, indicating the tolerance of plants towards BPS and PS co-contamination. In addition, plants enriched BPS from soil, and a major part of absorbed BPS was accumulated in roots, as supported by the higher BCF value in roots compared with leaves. Besides, the low TF (<1) suggested the capacity of plants to accumulate BPS in roots, and less translocation to leaves. PS negatively affected the translocation of BPS in plants. PS with large size (5 μm) also increased the distribution of BPS in organelles. Exposure risk assessment suggested low concern of BPS carried in plants to human health. This study underlines the bioaccumulation of BPS in plants, and the effects of PS in the translocation process.

Intergenerational toxic effects of parental exposure to bisphenol AF on offspring and epigenetic modulations in zebrafish

Bisphenol AF (BPAF), an endocrine-disrupting chemical, has been detected in various environmental media because of its wide industrial applications. Meanwhile, substances that are known to be toxic to the reproductive system have been observed to interfere with the development of the offspring following parental exposure. This study was aimed at determining the gender-dependent intergenerational effects of BPAF on offspring development following either paternal or maternal exposure of adult zebrafish to an environmental concentration of BPAF. Four-month-old zebrafish (F0) were exposed to 10 μg/L of BPAF for 28 days, the developmental endpoints of F1 embryos were then tested without further treatment with BPAF. The results show that paternal BPAF exposure decreased the hatching rate, increased mortality, and shortened the body lengths of F1 larval offspring. In addition, it changed DNA and m⁶A RNA methylation gene expression levels in F0 testes and F1 larvae. Although maternal exposure increased mortality and enhanced antioxidant enzyme activities in F1 larvae, only DNA methylation gene expression was altered in F0 ovaries and F1 larvae. In addition, a short term BPAF exposure of zebrafish embryos from 4 h post-fertilization (hpf) until 120 hpf similarly impaired the early development of the larvae but only at a level relatively higher than 10 μg/L; and DNA and RNA methylation gene expression was regulated to some extent in BPAF exposure groups. Overall, our results indicate the gender-specific effects of BPAF on offspring development and epigenetic modulations, suggesting a relatively high susceptibility within the exposure window during gametogenesis and early embryonic developmental stages to environmental chemicals.

Post COVID-19 pandemic: Disposable face masks as a potential vector of antibiotics in freshwater and seawater

With the outbreak and widespread of the COVID-19 pandemic, large numbers of disposable face masks (DFMs) were abandoned in the environment. This study first investigated the sorption and desorption behaviors of four antibiotics (tetracycline (TC), ciprofloxacin (CIP), sulfamethoxazole (SMX), and triclosan (TCS)) on DFMs in the freshwater and seawater. It was found that the antibiotics in the freshwater exhibited relatively higher sorption and desorption capacities on the DFMs than those in the seawater. Here the antibiotics sorption processes were greatly related to their zwitterion species while the effect of salinity on the sorption processes was negligible. However, the desorption processes were jointly dominated by solution pH and salinity, with greater desorption capacities at lower pH values and salinity. Interestingly, we found that the distribution coefficient (K_d) of TCS (0.3947 L/g) and SMX (0.0399 L/g) on DFMs was higher than those on some microplastics in freshwater systems. The sorption affinity of the antibiotics onto the DFMs followed the order of TCS > SMX > CIP > TC, which was positively correlated with octanol-water partition coefficient (log K_ow) of the antibiotics. Besides, the sorption processes of the antibiotics onto the DFMs were mainly predominated by film diffusion and partitioning mechanism. Overall, hydrophobic interaction regulated the antibiotics sorption processes. These findings would help to evaluate the environmental behavior of DFMs and to provide the analytical framework of their role in the transport of other pollutants.

Accurate Removal of Toxic Organic Pollutants from Complex Water Matrices

Characteristic emerging pollutants at low concentration have raised much attention for causing a bottleneck in water remediation, especially in complex water matrices where high concentration of interferents coexist. In the future, tailored treatment methods are therefore of increasing significance for accurate removal of target pollutants in different water matrices. This critical review focuses on the overall strategies for accurately removing highly toxic emerging pollutants in the presence of typical interferents. The main difficulties hindering the improvement of selectivity in complex matrices are analyzed, implying that it is difficult to adopt a universal approach for multiple targets and water substrates. Selective methods based on assorted principles are proposed aiming to improve the anti-interference ability. Thus, typical approaches and fundamentals to achieve selectivity are subsequently summarized including their mechanism, superiority and inferior position, application scope, improvement method and the bottlenecks. The results show that different methods may be applicable to certain conditions and target pollutants. To better understand the mechanism of each selective method and further select the appropriate method, advanced methods for qualitative and quantitative characterization of selectivity are presented. The processes of adsorption, interaction, electron transfer, and bond breaking are discussed. Some comparable selective quantitative methods are helpful for promoting the development of related fields. The research framework of selectivity removal and its fundamentals are established. Presently, although continuous advances and remarkable achievements have been attained in the selective removal of characteristic organic pollutants, there are still various substantial challenges and opportunities. It is hopeful to inspire the researches on the new generation of water and wastewater treatment technology, which can selectively and preferentially treat characteristic pollutants, and establish a reliable research framework to lead the direction of environmental science.

Occurrence, distribution, and risk assessment of bisphenol analogues in Luoma Lake and its inflow rivers in Jiangsu Province, China

Bisphenol analogs (BPs) are widely used in industrial and commercial products and have been detected in surface water, sediment, sewage, and sludge. The presence of BPs in the natural environment poses threats to the aquatic ecosystem and human health. The concentration, distribution, seasonal variation, and risk assessment of BPA and BPA structural analogs including BPB, BPF, BPS, BPZ, BPAF, and BPAP in surface water and sediment during dry season and flood season in Luoma Lake and its inflow rivers in Jiangsu Province, China, were investigated in this study. The detection frequency of BPA and BPF was 100%. Although the use of BPA is restricted, BPA is still the dominant BPs in surface water and sediment. The concentration of BPs in surface water during flood season was higher than that in dry season. The concentrations of BPs in Fangting River, Zhongyun River, and Bulao River were higher than those in Luoma Lake. The average concentrations of BPs in surface water were in the order of BPA > BPF> BPS> BPB > BPZ > BPAF> BPAP. Compared with other studies, the concentration of BPs in Luoma Lake was moderate. There is no significant spatial distribution and difference in seasonal variation of BPs concentration in sediment (p > 0.05). Compared with other studies, the contamination of BPs in sediment of Luoma Lake was relatively low. Risk quotient (RQ) was used to evaluate the ecological risk of BPs in water environment, and the 17β estradiol equivalent (EEQ) method was used to estimate the estrogenic activity of BPs. The risk assessment showed no high ecological risk (RQ < 1.0) and estrogenic risk (EEQ < 1.0 ng/L) in dry season and flood season. The estimated RQ and EEQ_t indicated that the ecological and human health impacts were negligible in the short term.

Iron molydate catalyzed activation of peroxymonosulfate for bisphenol AF degradation via synergetic non-radical and radical pathways

Though molybdate oxides have been demonstrated as desirable catalysts for environmental remediation, the mechanism of catalytic activation of peroxymonosulfate (PMS) by iron (II) molybdate (FeMoO₄) remains unclear. In this study, FeMoO₄ was synthesized and applied for the activation of PMS to degrade bisphenol-AF (BPAF). FeMoO₄ showed excellent catalytic activity, high stability, and superior mineralization. The influence of operation parameters (i.e., FeMoO₄ dosage, PMS concentration, initial pH, co-existing anions, and temperature) on the removal of BPAF were also investigated in detail. Furthermore, the possible oxidation mechanism was proposed via the chemical quenching tests and electron spin resonance (ESR) analysis, which certified that both free radical (SO₄^-• and ^•OH) and non-radical (¹O₂) were the main reactive oxygen species for degrading BPAF. X-ray photoelectron spectroscopy (XPS) analysis indicated that the radicals were mainly generated via the continuous circulation of Fe³⁺/Fe²⁺ and Mo⁶⁺/Mo⁴⁺ redox cycles to enhance PMS activation. Finally, the degradation pathways of BPAF was proposed based on LC/MS results. This work showed the notable potential of the FeMoO₄/PMS system for degrading organic contaminants in the environment remediation and would promote the understanding of the mechanism of Fe-based molybdate in advanced oxidation.

Transformation of bisphenol AF by chlorination: kinetic study and product identification

Bisphenol AF (BPAF), commonly used as a substitute for bisphenol A (BPA), is also an endocrine disruptor with cytotoxicity, neurotoxicity, genotoxicity, and biotoxicity. In this study, we found that BPAF could be effectively degraded by free chlorine. The second order rate constant of the reaction ranged from 1.67 to 126.67 M^-1·s^-1 in the pH range of 5.0-11.0. Nineteen products were detected by LC-Q-TOF-MS analysis, including chlorinated BPAF (i.e., mono/di/tri/tetrachloro-BPAF), 8 dimers, and 6 trimers. According to the identified products, two transformation pathways of electrophilic substitution and electron transfer are proposed. Humic acid (HA) could inhibit the degradation rate of BPAF due to its ability to reduce the reactive BPAF radical intermediates to the parent compound. The addition of low concentrations of Br^- and I^- accelerates the reaction rate of BPAF, due to the formation of HOBr and HOI with a higher oxidizing capacity. In seawater, BPAF degraded rapidly, and 16 new halogenated products were formed. Theoretical calculation shows that electrophilic substitution is more prone to occur at the ortho position of the hydroxyl group to form chlorinated products, while electron transfer tends to occur at the hydroxyl oxygen, resulting in the formation of BPAF radical and its subsequent coupling products.

Sorption and leaching behaviors between aged MPs and BPA in water: The role of BPA binding modes within plastic matrix

Due to the hydrophobicity and large specific surface area microplastics (MPs) have become the vector for the migration of environmental organic pollutants. Environmental aging process affects the physiochemical structure of MPs and their corresponding environmental behaviors, in which the effect of bisphenol A (BPA) binding mode within plastic matrix on aging behaviors of MPs is not reported. In this work, the structural properties and BPA sorption behaviors of low density polyethylene (LDPE) MPs with BPA additives and polycarbonate (PC) MPs with BPA monomers exposed to three types of artificial accelerated aging processes including UV/H₂O, UV/H₂O₂, and UV/Cl₂ systems were comparatively investigated. Virgin LDPE and PC exhibited obvious leakage of BPA additives or monomers. Aged LDPE had stronger sorption ability towards BPA in water environment with no observed leakage of BPA additives. While, aged PC had extremely high leakage of BPA monomers, which is similar to virgin PCs and was proved to be a persistent source of BPA release. The BPA sorption on aged LDPE or leaching from aged PC was influenced by aging processes, water pH, salinity, co-existing estradiol (E2), and water sources. This study reveals the potential ecological and environmental risks of MPs containing toxic additives/monomers during aging processes from a new perspective.

Structural elucidation of bisphenol E and bisphenol S photoinduced by-products by high-resolution electrospray ionisation mass spectrometry and tandem mass spectrometry

RATIONALE

Bisphenol E (BPE) and bisphenol S (BPS) have recently replaced bisphenol A as monomers for producing polycarbonates. However, BPE and BPS can pose hazards as they are known to be endocrine disruptors. Despite the huge increase in their use, there is a lack of data regarding the toxicity and effects of BPE and BPS.

METHODS

We investigated the photoinduced transformation of BPE and BPS when subjected to sun-simulated radiation and using TiO₂ as a photocatalyst. Analyses of BPE, BPS and their by-products were performed by high-performance liquid chromatography/high-resolution mass spectrometry (HPLC/HRMS) using an orbitrap mass analyzer in negative electrospray ionisation (ESI) mode. The chromatographic separations were achieved by employing a C18 reversed-phase column, and the transformation products (TPs) were elucidated structurally using HRMS and multistage MS experiments performed in collision-induced dissociation (CID) mode.

RESULTS

The transformation of bisphenol S involved the formation of twelve by-products, while ten TPs were detected following BPE degradation. For bisphenol S, the cleavage of the molecule is a very important transformation route, together with the hydroxylation of the substrate to provide mono- and poly-hydroxylated TPs. For bisphenol E, the two main routes were hydroxylation and ring opening. Acute toxicity for BPS, BPE and their TPs was assessed using the Vibrio fischeri assay, highlighting that their initial transformation involved the formation of TPs that were more toxic than the parent compound.

CONCLUSIONS

The HPLC/HRMS method developed was useful for characterising and identifying newly formed TPs from bisphenol E and bisphenol S. This study aimed to examine the structure of twenty by-products identified during TiO₂ -mediated photolysis and to evaluate acute toxicity over time.

Persistence of three bisphenols and other trace organics of concern in anaerobic sludge under methanogenic conditions

The degradation and distribution of bisphenol A (BPA), bisphenol S (BPS) and bisphenol AF (BPAF) were evaluated in dilute anaerobic sludge slurries amended with a single bisphenol or a mixture of all three and maintained under methanogenic conditions over a 28-d period. No significant degradation of the bisphenols was observed in methane-generating microcosms. Rapid sorption to sludge particles was the primary removal process with sorption observed: BPAF > BPA > BPS. Several other trace organic chemicals of concern in the sludge were detected using quadrupole time of flight mass spectrometry. Of those detected, triclosan and triclocarban had sufficiently high intensities to quantify changes over the 28-d period in the bisphenol-amended microcosms. Similar to the bisphenols, triclosan and triclocarban concentrations also did not significantly change over the 28-d period with concentrations quantified at 2021 ± 627 and 1864 ± 769 μg/kg dry weight, respectively. Findings exemplify that methane-generating microcosms do not appear conducive to significant degradation of trace organics of concern in anaerobic sludge digesters.

The sinking behavior of micro-nano particulate matter for bisphenol analogues in the surface water of an ecological demonstration zone, China

Bisphenol analogues (BPs) have been widely used in industrial production as substitutes of bisphenol A (BPA). The demand and production of BPs are growing rapidly in China. In this study, the pollution levels and distribution characteristics of five BPs were investigated in surface water from rivers located in different land-use types of an ecological demonstration zone. All BPs were detected at least once in the traditionally dissolved phase, colloidal phase and suspended particulate matter (SPM) with the mean total concentrations of 465.1 ng L-1, 114.4 ng L-1 and 11.3 μg g-1 dry weight, respectively. BPA is the dominant BP in the traditionally dissolved phase and colloidal phase, with the mean contribution rates of 77.6% and 70.7%, respectively, followed by bisphenol F (BPF) and/or bisphenol S (BPS). The colloids as the important sinks of contaminants contributed 42.3% of bisphenol Z, 37.3% of BPF, 24.9% of BPA, 22.3% of BPAF and 18.4% of BPS in the traditionally dissolved phase. However, BPA alternatives are found primarily in the SPM, in which the contribution rate of BPA ranges from 0.6% to 48.1%, with the mean contribution of 12.4%. Based on BP concentrations in the traditionally dissolved phase, moderate ecological risk levels of BPA and BPF towards aquatic organisms were posed. Fish and/or algae are the most sensitive aquatic organisms, and hence chronic toxicological effects should not be ignored especially in fish.

Pregnancy-specific physiologically-based toxicokinetic models for bisphenol A and bisphenol S

Predictions from physiologically based toxicokinetic (PBTK) models can help inform human health risk assessment for potentially toxic chemicals in the environment. Bisphenol S (BPS) is the second most abundant bisphenol detected in humans in the United States, after bisphenol A (BPA). We have recently demonstrated that BPS, much like BPA, can cross the placental barrier and disrupt placental function. Differences in physicochemical properties, toxicokinetics, and exposure outcomes between BPA and other bisphenols prevent direct extrapolation of existing BPA PBTK models to BPS. The current study aimed to develop pregnancy-specific PBTK (p-PBTK) models for BPA and BPS, using a common p-PBTK model structure. Novel paired maternal and fetal pregnancy data sets for total, unconjugated, and conjugated BPA and BPS plasma concentrations from three independent studies in pregnant sheep were used for model calibration. The nine-compartment (maternal blood, liver, kidney, fat, placenta and rest of body, and fetal liver, blood and rest of body) models simulated maternal and fetal experimental data for both BPA and BPS within one standard deviation for the majority of the experimental data points, highlighting the robustness of both models. Simulations were run to examine fetal exposure following daily maternal exposure to BPA or BPS at their tolerable daily intake dose over a two-week period. These predictive simulations show fetal accumulation of both bisphenols over time. Interestingly, the steady-state approximation following this dosing strategy achieved a fetal concentration of unconjugated BPA to levels observed in cord blood from human biomonitoring studies. These models advance our understanding of bisphenolic compound toxicokinetics during pregnancy and may be used as a quantitative comparison tool in future p-PBTK models for related chemicals.

Occurrence, toxicity and ecological risk of Bisphenol A analogues in aquatic environment - A review

Bisphenol analogues (BPs) have been widely applied to industry as the substitutes for bisphenol A (BPA), which have been detected frequently in surface water, sediment, sewage and sludge. The presence of BPs in natural environment could pose risks to the aquatic ecosystem and human health. This study outlined the occurrence, toxicity of BPs in aquatic environment and manifested their potential ecological risk to the aquatic ecosystem throughout the world. As for occurrence, BPA was losing its dominance, while BPs were occupying a large part, especially for bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF). In some heavily polluted areas, BPs concentration reached µg/L in aquatic environment, which in the effluent of sewage plants was higher than that in the surface water. BPs content in sludge and sediment was more than that in the aqueous phase. All BPs other than BPS and Bisphenol P (BPP) had moderate toxicity. The current data supports that exposure to BPs may have adverse effects on dysfunction of endocrine system such as thyroid hormone concentration, enzyme activity, and even cell dysfunction, gene damage and chromosomal abnormalities. According to the risk quotient (RQ), BPF shows the highest ecological risk in China, Japan and South Korea, followed by BPA and BPS. The occurrence of bisphenols and their neurotoxicity on aquatic organisms merit further investigation.

Heterogeneous catalytic oxidation degradation of BPAF by peroxymonosulfate active with manganic manganous oxide: Mineralization, mechanism and degradation pathways

In this study, the catalytic ability and mechanisms involved in activating peroxymonosulfate (PMS) with Mn₃O₄ and the degradation pathways of bisphenol-AF (BPAF) removal was investigated. SO₄^-• and ·OH which were explored by and scavenging tests were the major reactive radicals in the Mn₃O₄/PMS system. A simple simulation algorithm was also used to calculate the relative concentrations of SO₄^-• ([SO₄^-•]) and ·OH ([·OH]) which were 8.39 × 10 ^-15 M and 6.96 × 10 ^-13 M, respectively. The mechanism for the electron transfer between the Mn (II) and Mn (III) species was discussed. Three degradation pathways of BPAF were determined by the GC/MS and LC/MS technology, including chemical mechanism of oxidation, hydroxylation, electron transfer, polymerization, and ring-cleavage. In addition, the results suggested that the Mn₃O₄/PMS system had an efficient total organic carbon (TOC) removal rate and excellent environmental adaptability, the removal rate of TOC being as high as 73.2% in the control condition. Furthermore, the reuse experiments and the comparison on the structural and componential changes of Mn₃O₄ powder before and after reaction demonstrated that the Mn₃O₄ catalyst possessed excellent stability and reusability. Finally, a maximum BPAF degradation of approximately 90.0% was achieved on the optimal conditions for 500 mg/L Mn₃O₄ dosage, 4 mM PMS concentration, 7.0 ± 0.2 initial pH, and 5 mg/L BPAF concentration respectively. And the effect of the coexisting anions and natural environmental water quality were also considered. This study demonstrated the Mn₃O₄/PMS system can be considered as a green approach for the removal of environmental reluctant pollutants.

Preparation of nitrogen-containing carbon using a one-step thermal polymerization method for activation of peroxymonosulfate to degrade bisphenol A

Nitrogen-containing carbon materials (NCC-x) are promising metal-free catalysts for activation of peroxymonosulfate (PMS) to treat with aqueous organic pollutants. In this study, NCC-x were synthesized via a facile thermal polymerization method using urea and terephthalaldehyde as precursors. This method was derived from the polymerization method of graphitic carbon nitride (g-C₃N₄) and the reaction between the precursors was based on Schiff base chemistry. Compared with the synthesis of g-C₃N₄ using urea as the precursor, formation of a melamine ring was inhibited and the cyano groups were produced in NCC-x during the polymerization process. The obtained NCC-x catalysts had high specific surface areas, many graphite-nitrogen active sites, and high degrees of graphitization, thus exhibiting excellent activities for the degradation of bisphenol A via PMS activation. This study introduces a convenient method to obtain a highly efficient nitrogen-containing carbon PMS activator and the results are useful for the development of bisphenol A treatment by PMS activation using carbon-containing materials.

Toxicokinetics and bioaccumulation characteristics of bisphenol analogues in common carp (Cyprinus carpio)

Toxicokinetics and bioconcentration of eight common bisphenol analogues, including bisphenol A (BPA), -B, -C, -E, -S, -Z, -AF, and -AP in common carp (Cyprinus carpio) were investigated. Both free (BP_free) and total forms (BP_total) of the bisphenols were measured in various fish tissues. The conjugated forms of bisphenols were calculated based on BP_free and BP_total. The calculated bioconcentration factors (BCFs) based on the total bisphenols (BP_total) in the carp whole body were in the range of 0.3-320, agreeing with previous field results from Taihu Lake, China. The elimination rate constant (k_e) positively correlated with the fraction of conjugated form (f_conjugated), which displayed negative correlation with their log K_ow (r = -0.861, p < 0.05), indicating that conjugation facilitated their elimination and those with higher hydrophobicity were more difficult to be eliminated. Except BPA, the concentrations of all bisphenols in the carp tissues were in the order of kidney > liver ≫ muscle. The uptake rate constants (k_u) in kidney (r = 0.836, p < 0.05) and in liver (r = 0.863, p < 0.05) displayed significantly positive correlations with BCFs, and k_u in kidney was greater than in liver except BPA. These results indicated that kidney and liver played important roles in accumulating bisphenols in carp, and kidney made more contribution than liver for most bisphenols. Biliary excretion predominated for elimination of most bisphenols while BPA and BPS were mainly through urinary excretion.

The EuroMix human biomonitoring study: Source-to-dose modeling of cumulative and aggregate exposure for the bisphenols BPA, BPS, and BPF and comparison with measured urinary levels

BACKGROUND

Bisphenol A (BPA) and, with increasing occurrence, its analogs bisphenol S (BPS) and bisphenol F (BPF) are applied in many consumer products, leading to humans being exposed from a vast number of sources and via several routes. Estrogenic and anti-androgenic effects are exerted by the chemical BPA, and also by its analogs. Therefore, realistic exposure assessments are needed for assessing risks related to cumulative exposure.

OBJECTIVES

Biomonitoring for BPA, BPS, and BPF was conducted in a human study embedded in the EU project EuroMix and the measured urinary concentrations were compared to source-to-dose calculations for source allocation and plausibility test of the model.

METHODS

For two 24-hour study periods separated by 2-3 weeks, 144 adult volunteers in Norway kept detailed diaries on food consumption, personal care product (PCP) use, and thermal paper (TP) handling. Concurrently, 24 h urine was collected and urinary levels of BPA, BPS, and BPF were analyzed using ultra-high performance liquid chromatography and tandem mass spectrometry (UPLC-MS-MS). In line with the information obtained from the first study day, bisphenol exposure from food, PCPs, TP, and dust was modeled primarily individual-based with probabilistic models. Estimates for BP excretion over 24 h were obtained with the models and compared to measured amounts.

RESULTS

Modeled aggregate internal exposures covered the full range of measured urinary amounts for all BP analogs. In general, individual-based medians of modeled BPA exposures were in good agreement with the measurements, but individual-specific correlation was lacking. Modeled exposures mostly underestimated BPS and BPF levels in participants with positive measurements (53% and 8%), except for the P95 values of modeled BPS exposure that were higher than measured amounts if TP was handled. Most likely, diet and TP were the sources contributing the most to BP exposure in this study. Urinary measurements did not reveal a significant correlation between the amounts of canned food consumed, the number of PCPs used, or the number of TP handling events and levels of BPA, BPS, or BPF.

CONCLUSIONS

The good agreement between the ranges of modeled BPA exposure and measured BPA amounts indicates that available concentrations, especially from the main exposure source food, mirror the exposure situation realistically, and suggests that the exposure model considers the relevant exposure sources. The lack of individual-specific correlations means that the individual measured amounts and modeled exposures did not vary in parallel, e.g. due to mismatch of BP concentrations in food, TP, and other sources, or delayed internal exposure. The underestimation of modeled BPS and BPF exposure suggests that not all relevant sources were included in the respective exposure models. This could be due to a lack of input data, e.g. for food items, or due to an increased replacement of BPA with structural analogs compared to the used concentration and occurrence data.

New insights on the understanding of the high adsorption of bisphenol compounds on reduced graphene oxide at high pH values via charge assisted hydrogen bond

The adsorption characteristics and mechanisms of ionic organic compounds dependent on their dissociation species are still unclear, which hindered the understanding of their environmental behavior and risks. This study compared the sorption of four bisphenol compounds (BCs) on graphite adsorbents, with a specific emphasis on the roles of charge assisted hydrogen bond (CAHB). The negative correlations between the localized orbital locator integrated π over plane index and the single point adsorption coefficient K_d of the four BCs indicated that π-π interaction was an important mechanism for BCs adsorption on graphite adsorbents. Based on the speciation distribution calculation and the modeling of pH-dependent adsorption, the apparent adsorption coefficient of different species were obtained. Except for bisphenol S, the K_d^HA- of BC monovalent anions was 2.6 times to one order magnitude higher than that of the neutral species. According to the density functional theory (DFT) calculation, strong CAHB is expected between BC monovalent anions and graphite adsorbents, indicating that CAHB overcame the enhanced electrostatic repulsion and became the dominant adsorption mechanism. This study highlighted the importance of CAHB in the adsorption of ionic organic compounds on carbonaceous materials, which should be carefully taken into consideration for their environmental fate studies.

Bisphenol AF promotes estrogen receptor-positive breast cancer cell proliferation through amphiregulin-mediated crosstalk with receptor tyrosine kinase signaling

Exposure to bisphenol A (BPA), an endocrine-disrupting compound, is associated with increased risk of estrogen-related diseases, including estrogen receptor-positive (ER⁺) breast cancer. Although bisphenol analogs, i.e. bisphenol AF (BPAF), have replaced BPA in industrial settings, increasing data indicate that these alternatives may have similar or even more potent estrogenic effects. As such, BPAF exhibits increased ER binding affinities than BPA in biochemical assays. However, preclinical studies exploring the effects of BPAF on ER⁺ breast cancer are missing mechanistic data. Thus, we aimed to characterize the effects of BPAF on MCF-7 and T47D ER⁺ breast cancer cells with mechanistic insight. We found that BPAF promoted cell growth and cell cycle progression concurrently with BPAF-induced ERα transcriptional activity and ER-RTK signaling activation. ER signaling blockage revealed that BPAF-induced cell proliferation and ER-RTK crosstalk were ER-dependent. Gene expression data demonstrated that AREG is a sensitive target of BPAF in our in vitro models. Importantly, we determined that AREG upregulation is necessary for BPAF-induced cellular responses. Ultimately, our novel finding that AREG mediates BPAF-induced ER-RTK crosstalk in ER⁺ breast cancer cells supports future studies to characterize the impact of BPAF on human ER⁺ breast cancer risk and to assess the safety profile of BPAF.

Is bisphenol S a safer alternative to bisphenol A in terms of potential fetal exposure ? Placental transfer across the perfused human placenta

The aim of our study was to evaluate the bidirectional transfer of Bisphenol S (BPS) and its main metabolite, BPS Glucuronide (BPSG), using the model of perfused human placenta and to compare the obtained values with those of Bisphenol A (BPA) and BPA Glucuronide. Fourteen placentas at term were perfused in an open dual circuit with deuterated BPS (1 and 5 μM) and non-labelled BPSG (2.5 μM) and a freely diffusing marker antipyrine (800 ng/ml) in the presence of albumin (25 mg/ml). In a second experiment, the potential role of P-glycoprotein in the active efflux of BPS across the placental barrier was studied using the well-established P-glycoprotein inhibitor, PSC833 (2 and 4 μM). Placental transfer of BPS was much lower than that of BPA in both directions. The placental clearance index of BPS in the materno-fetal direction was three times lower than in the opposite direction, strongly suggesting some active efflux transport. However, our results show that P-glycoprotein is not involved in limiting the materno-fetal transfer of BPS. Placental transfer of BPSG in the fetal compartment was almost non-existent indicating that, in the fetal compartment, BPSG originates mainly from feto-placental metabolism. The feto-maternal clearance index for BPSG was 20-fold higher than the materno-fetal index. We conclude that the blood-placental barrier is much more efficient in limiting fetal exposure to BPS than to BPA, indicating that the placenta has a crucial role in protecting the human fetus from BPS exposure.

Adsorption mechanisms of five bisphenol analogues on PVC microplastics

Polyvinyl chloride (PVC) plastics are easily embrittled and decomposed to microplastics in an aquatic environment. The plasticizers such as bisphenol A (BPA), bisphenol S (BPS) and their analogues might be released and adsorbed by the PVC microplastics causing consequential pollution to the ecosystem. Herein, a systematic study was performed to determine the adsorption mechanisms of five bisphenol analogues (BPA, BPS, BPF, BPB and BPAF) on PVC microplastics. The maximum adsorption efficiency reached 0.19 ± 0.02 mg·g^-1 (BPA), 0.15 ± 0.01 mg·g^-1 (BPS), 0.16 ± 0.01 mg·g^-1 (BPF), 0.22 ± 0.01 mg·g^-1 (BPB), and 0.24 ± 0.02 mg·g^-1 (BPAF) at PVC dosage of 1.5 g·L^-1. The kinetics study shows that the adsorption processes can be divided into three stages including external mass transport, intraparticle diffusion and dynamic equilibrium. The isotherm modeling shows a better fit of the adsorption results to the Freundlich isotherm compared to the Langmuir model. The thermodynamic study indicates the adsorption of all bisphenols as exothermic processes. Furthermore, the adsorption mechanisms of bisphenols were explicated intensively, with respect to hydrophobic interactions, electrostatic forces, and noncovalent bonds. A positive effect of hydrophobic interactions was identified for bisphenols adsorption on PVC microplastics, but an obvious inhibition by electrostatic repulsions was revealed for BPF due to its ionization in the neutral solution. In addition, noncovalent bonds (hydrogen and halogen bonds) may promote the adsorption of bisphenols on PVC microplastics. Finally, the desorption and competitive adsorption of five bisphenol analogues on the microplastics were provided together with a perspective for future works.

Comparative study on ferrate oxidation of BPS and BPAF: Kinetics, reaction mechanism, and the improvement on their biodegradability

Bisphenol S (BPS) and bisphenol AF (BPAF) were increasingly consumed and these compounds are resistant to environmental degradation. Herein, ferrate oxidation of BPS and BPAF was investigated, and biodegradability of the oxidation products was examined. The second-order reaction rate constants of ferrate with BPS and BPAF were 1.3 × 10³ M^-1s^-1 and 3 × 10² M^-1s^-1, respectively, at pH 7.0, 25 °C. In the oxidation process, some BPS molecules dimerized, while other BPS molecules were oxidized through oxygen-transfer process, leading to the formation of hydroxylation products and benzene-ring cleavage products. The dominant reaction of BPAF with ferrate was oxygen-transfer process, and BPAF was degraded into lower molecular weight products. The variation of assimilable organic carbon (AOC) suggested that the biodegradability of BPAF and BPS was largely improved after ferrate oxidation. Compared with the BPS oxidation products, the BPAF oxidation products were easier to be bio-consumed. Pure culture test showed that BPAF inhibited the growth of Escherichia coli, while ferrate oxidation completely eliminated this toxic effect. Co-existing humic acid (HA, 1 mg C/L to 5 mg C/L) decreased the removal of BPS and BPAF with ferrate. Compared with BPAF, more oxidation intermediates formed in the ferrate oxidation of BPS may be reduced by HA to the parent molecular. Thus, the inhibition effect of HA on the ferrate oxidation of BPS was more obvious than that on BPAF.

Heterogeneous activation of peroxymonosulfate for bisphenol AF degradation with BiOI0.5Cl0.5

This study represents the first investigation on the application of peroxymonosulfate (PMS) for the degradation of bisphenol AF (BPAF) using halogen bismuth oxide composites (BiOI_0.5Cl_0.5). The hierarchical BiOI_0.5Cl_0.5 was successfully synthesized and systematically characterized with multifarious techniques including XRD, SEM, FTIR and XPS to investigate the morphology and physicochemical properties of the samples. Several parameters affecting the degradation efficiency including catalyst dosage, PMS loading, and pH value were elucidated. Inorganic ions such as HCO₃⁻ showed significant inhibition in the BiOI_0.5Cl_0.5/PMS process due to the quenching effect. The effect of various water matrices including tap water and surface water on the removal of BPAF was studied to indicate that the present reaction system shows great potential for cleaning BPAF waste water. Furthermore, the production of sulfate radicals and hydroxyl radicals was validated through radical quenching and ESR tests, thus a possible oxidation mechanism was proposed. Overall, these results reveal that the activation of PMS by the BiOI_0.5Cl_0.5/PMS system is an efficient and promising advanced oxidation technology for the treatment of BPAF-contaminated waters and wastewaters.

This study represents the first investigation on the application of peroxymonosulfate (PMS) for the degradation of bisphenol AF (BPAF) using halogen bismuth oxide composites (BiOI_0.5Cl_0.5).

Bisphenol A, Bisphenol AF, di-n-butyl phthalate, and 17β-estradiol have shared and unique dose-dependent effects on early embryo cleavage divisions and development in Xenopus laevis

Bisphenol A (BPA), Bisphenol AF (BPAF), and di-n-butyl phthalate (DBP) are widespread compounds used in the production of plastics. We used Xenopus laevis to compare their effects on early embryo cell division and development. Directly after in vitro fertilizations, embryos were exposed to BPA, BPAF, DBP, or 17β-estradiol (E2) for up to 96 h. BPA (1-50 μM) and BPAF (0.003-25 μM) caused disrupted cleavage divisions, slowed cytokinesis, and cellular dissociation within 1-6 h. Flexures of the spinal cord, shorter body axis/tail, craniofacial malformations, and significant mortality occurred with environmentally relevant doses of BPAF (LC₅₀ = 0.013 μM). DBP (10-200 μM) showed similar effects, but with severe ventral edema. There were both shared and unique effects of all compounds, with BPAF having the greatest potency and toxicity (BPAF > BPA > estradiol > DBP). These findings underscore the pleiotropic effects of widespread toxicants on early development and highlight the need for better toxicological characterization.

A highly ordered honeycomb-like nickel(III/II) oxide-enhanced photocatalytic fuel cell for effective degradation of bisphenol A

The honeycomb-like nickel(III/II) oxide interpenetrated framework arrays labelled as H-NiO_x are used as cathode catalysts for the degradation of bisphenol A (BPA) in visible light-excited fuel cells. The nanoparticle close-packed NiO_x aggregates (C-NiO_x) and H-NiO_x are prepared by conventional electrodeposition (ED) and advanced oxidation-associated electrodeposition (AO-ED) strategies, carried out by multiple voltammetry controlled in the potential ranges of 0 to -1.3 V and 1.3 to -1.3 V (vs. SCE), respectively. Compared with C-NiO_x, the H-NiO_x frameworks with smaller charge transfer resistance and higher surface-confined redox-active centers exhibit larger cathode electrocatalytic activity for the photocatalytic degradation of BPA. The NaClO can act as a sacrificial agent to sustain the integrity and stability of H-NiO_x cathode. The H-NiO_x-assisted BPA degradation conditions are optimized by changing process variables. The BPA is degraded by 48.5% within 120 min in photocatalytic BPA (1.0 mmol L^-1, pH 13) fuel cell employing H-NiO_x cathode, CdS/TiO₂ photoanode and 0.2 mol L^-1 NaClO catholyte, and its degradation rate conforms to the first-order reaction kinetic model. The H-NiO_x can remarkably enhance the performances of the photocatalytic fuel cell, achieving a 4.1-fold or 15.2-fold increase in the short circuit current and maximum power density compared with that using bare cathode.

Elevated Concentrations of Bisphenols, Benzophenones, and Antimicrobials in Pantyhose Collected from Six Countries

Pantyhose, a skin-tight item of clothing made of synthetic fibers and worn by women in many countries, is a source of exposure to several endocrine-disrupting chemicals. Little is known regarding the occurrence of and dermal exposure to chemicals present in pantyhose. In this study, concentrations and profiles of 23 endocrine-disrupting chemicals, including bisphenols, benzophenones, chlorophenols, parabens, and triclocarban (TCC), were determined in 74 pantyhose samples collected from 6 countries. Pantyhose samples were analyzed by two extraction methods: complete dissolution and ultrasonic extraction. Dissolution of the fabric in 1,1,1,3,3,3-hexafluoro-2-propanol/chloroform yielded concentrations of several target chemicals that were up to 286 times higher than in the ultrasonic extraction. Bisphenol S (BPS) and bisphenol A (BPA) were found in 100% and 96% of the samples at median concentrations of 1430 and 14.3 ng/g, respectively. Several brands of pantyhose contained BPS, bisphenol F (BPF), benzophenone-1 (BP-1), ethyl-paraben (EtP), and TCC at concentrations of milligrams per gram. Benzophenone-3 (BP-3), 4-hydroxy benzoic acid (4-HB), and methyl- (MeP) and propyl-parabens (PrP) were found in ≥85% of the samples at median concentrations on the order of several tens to hundreds of nanograms per gram of fabric. Pantyhose made in Japan and China with 21-50% Spandex contained the highest concentrations of BPS (2.2 mg/g), BP-1 (2.4 mg/g), and EtP (88 μg/g). Calculated dermal exposure doses to BPS, BP-1, and EtP by women via pantyhose were as high as 45 900, 50 600, and 1800 picograms per kilogram of body weight per day, respectively.

Physiologically Based Pharmacokinetic (PBPK) Modeling of the Bisphenols BPA, BPS, BPF, and BPAF with New Experimental Metabolic Parameters: Comparing the Pharmacokinetic Behavior of BPA with Its Substitutes

BACKGROUND

The endocrine disrupting chemical bisphenol A (BPA) has been facing stricter regulations in recent years. BPA analogs, such as the bisphenols S, F, and AF (BPS, BPF, and BPAF) are increasingly used as replacement chemicals, although they were found to exert estrogenic effects similar to those of BPA. Research has shown that only the parent compounds have affinity to the estrogen receptors, suggesting that the pharmacokinetic behavior of bisphenols (BPs) can influence their potency.

OBJECTIVES

Our goal was to compare the pharmacokinetic behaviors of BPA, BPS, BPF, and BPAF for different age groups after environmentally relevant external exposures by taking into account substance-specific metabolism kinetics and partitioning behavior. This comparison allowed us to investigate the consequences of replacing BPA with other BPs.

METHODS

We readjusted a physiologically based pharmacokinetic (PBPK) model for peroral exposure to BPA and extended it to include dermal exposure. We experimentally assessed hepatic and intestinal glucuronidation kinetics of BPS, BPF, and BPAF to parametrize the model for these BPs and calibrated the BPS model with a biomonitoring study. We used the PBPK models to compare resulting internal exposures and focused on females of childbearing age in a two-dimensional Monte Carlo uncertainty analysis.

RESULTS

Within environmentally relevant concentration ranges, BPAF and BPS were glucuronized at highest and lowest rates, respectively, in the intestine and the liver. The predominant routes of BPS and BPAF exposure were peroral and dermal exposure, respectively. The calibration of the BPS model with measured concentrations showed that enterohepatic recirculation may be important. Assuming equal external exposures, BPS exposure led to the highest internal concentrations of unconjugated BPs.

CONCLUSIONS

Our data suggest that the replacement of BPA with structural analogs may not lower the risk for endocrine disruption. Exposure to both BPS and BPAF might be more critical than BPA exposure, if their respective estrogenic potencies are taken into account. https://doi.org/10.1289/EHP2739.

Chlorination of bisphenol S: Kinetics, products, and effect of humic acid

Bisphenol S (BPS), as a main alternative of bisphenol A for the production of industrial and consumer products, is now frequently detected in aquatic environments. In this work, it was found that free chlorine could effectively degrade BPS over a wide pH range from 5 to 10 with apparent second-order rate constants of 7.6-435.3 M^-1s^-1. A total of eleven products including chlorinated BPS (i.e., mono/di/tri/tetrachloro-BPS), 4-hydroxybenzenesulfonic acid (BSA), chlorinated BSA (mono/dichloro-BSA), 4-chlorophenol (4CP), and two polymeric products were detected by high performance liquid chromatography and electrospray ionization-tandem quadrupole time-of-flight mass spectrometry. Two parallel transformation pathways were tentatively proposed: (i) BPS was attacked by stepwise chlorine electrophilic substitution with the formation of chlorinated BPS. (ii) BPS was oxidized by chlorine via electron transfer leading to the formation of BSA, 4CP and polymeric products. Humic acid (HA) significantly suppressed the degradation rates of BPS even taking chlorine consumption into account, while negligibly affected the products species. The inhibitory effect of HA was reasonably explained by a two-channel kinetic model. It was proposed that HA negligibly influenced pathway i while appreciably inhibited the degradation of BPS through pathway ii, where HA reversed BPS phenoxyl radical (formed via pathway ii) back to parent BPS.

pH-dependent KOW provides new insights in understanding the adsorption mechanism of ionizable organic chemicals on carbonaceous materials

The dominant adsorption mechanism of ionizable organic chemicals (IOCs) on carbonaceous materials is still unclear. This study used benzoic acid (BA), o-chlorobenzoic acid (2-CBA) and p-chlorobenzoic acid (4-CBA) as representatives of IOCs to investigate the dominant adsorption mechanism on graphene oxide (GO) and graphite (GP), with a specific emphasis on the impact of pH-dependent K_OW. The order of apparent adsorption of the investigated chemicals changed with pH, which could not be explained by their constant K_OW. According to our measurement, K_OW varied greatly with pH. The pH-dependent adsorption of BA, 2-CBA and 4-CBA were significantly correlated with pH-dependent K_OW for both GO and GP. Our observations indicated that the hydrophobic effects may dominate the apparent adsorption of BA, 2-CBA and 4-CBA on GO and GP. Electrostatic repulsion played a minor role in their reduced adsorption at high pH. Negative charge-assisted H-bond and π-π interactions may explain the adsorption of negatively charged BA, 2-CBA and 4-CBA on negatively charged GO. This study implied that pH-dependent K_OW rather than constant K_OW should be incorporated to understand IOC adsorption as affected by pH.