Cytotoxicity of seven bisphenol analogues compared to bisphenol A and relationships with membrane affinity data

Efficient enrichment and sensitive determination of endocrine disruptors in PPCPs by novel magnetic covalent organic framework extraction coupled with HPLC-MS/MS

Endocrine-disrupting chemicals (EDCs) are a growing class of pollutants commonly found in environmental matrices due to their extensive use in pharmaceuticals and personal care products (PPCPs). In this study, a novel magnetic covalent organic framework (COF), Fe3O4-COOH@TFP-BHBD, was successfully synthesized and utilized as an adsorbent for magnetic solid-phase extraction (MSPE) of EDCs from PPCPs. The core-shell structured adsorbent demonstrated a high specific surface area, strong magnetic responsiveness and excellent stability. A COF-MSPE-high-performance liquid chromatography-tandem mass spectrometry (COF-MSPE-HPLC-MS/MS) method was developed for the quantitative analysis of EDCs in PPCPs. Under the optimized condition, the detection and quantification limits of this method reached as low as 0.001-0.007 ng/mL and 0.004-0.025 ng/mL, respectively. This method was validated and proven capable to analyze real PPCP samples, while the spiked recovery rates in ranged from 85.62 to 107.83 % with RSD of 2.28-8.58 %. Moreover, the adsorption mechanism was investigated using density functional theory (DFT) calculations. The DFT results revealed that the efficient enrichment capacity of Fe3O4-COOH@TFP-BHBD for EDCs can be attributed to π-π interactions and hydrogen bondings. This proposed method provides excellent adsorption ability and sensitivity for the extraction and precise detection of EDCs in PPCPs.

Mechanisms of bisphenol A and its analogs as endocrine disruptors via nuclear receptors and related signaling pathways

Bisphenol A (BPA) is a widely used chemical that is slowly being phased out due to its toxic properties. The industry is therefore looking for alternatives in the form of BPA analogs. However, studies have shown that BPA analogs can have comparable or even stronger endocrine and toxic effects than BPA. This review describes various mechanisms and interactions of BPA analogs with individual nuclear receptors. They interfere with downstream signaling pathways not only by binding to the nuclear receptors, but also by various alternative mechanisms, such as altering receptor expression, affecting co-receptors, altering signal transduction pathways, and even epigenetic changes. Further studies are needed to fully investigate the potential synergistic and additive effects that may result. In the search for a less harmful alternative to BPA, affinity to the nuclear receptor may not be the decisive factor. We therefore recommend a different study approach to assess their effects on the endocrine system before new BPA analogs are introduced to the market to protect public health and the environment.

Comprehensive assessment of the safety of bisphenol A and its analogs based on multi-toxicity tests in vitro

As substitutes for bisphenol A (BPA), bisphenol analogs (BPs) have raised concerns due to their frequent environmental detection and unclear safety. Here, the cytotoxicity, endocrine disruption, neurotoxicity, aryl hydrocarbon receptor (AhR) activity, and genotoxicity of nine BPs and BPA were evaluated in three types of cell lines. Over half of the tested BPs exhibited greater cytotoxicity than BPA, with IC50 values showing a linear correlation with LogKow (R²=0.69). All tested BPs exhibited at least one endocrine-disrupting effect, notably estrogenic, which was observable even at 0.01-0.1 μM. Importantly, BPAF and BPAP exposure had widespread endocrine-suppressing effects. Moreover, all BPs (except BPP) and BPA increased SH-SY5Y cells apoptosis at 1-10 μM. Only BPF and BPP significantly increased 7-ethoxyresorufin-O-deethylase levels, highlighting their notable effects on AhR activity. BPAF significantly induced DNA damage at 1.25 μM, whereas BPA, BPF, and BPP induced damage at 20, 25, and 25 μM, respectively. Finally, ToxPi, a weighted scoring system, was used to rank the comprehensive toxicity of BPs, with 7 of 9 BPs showing higher scores than BPA. Collectively, BPs generally exhibited stronger comprehensive toxicity compared with BPA, emphasizing the urgent need for further research to confirm their potential health implications.

Application of Biomimetic Chromatography and QSRR Approach for Characterizing Organophosphate Pesticides

Biomimetic chromatography is a powerful tool used in the pharmaceutical industry to characterize the physicochemical properties of molecules during early drug discovery. Some studies have indicated that biomimetic chromatography may also be useful for the evaluation of toxicologically relevant molecules. In this study, we evaluated the usefulness of the biomimetic chromatography approach for determining the lipophilicity, affinity to phospholipids, and bind to plasma proteins of selected organophosphate pesticides. Quantitative structure-retention relationship (QSRR) models were proposed to understand the structural features that influence the experimentally determined properties. ACD/labs, Chemicalize, and alvaDesc software were used to calculate theoretical descriptors. Multilinear regression was used as the regression type, and feature selection was supported by a genetic algorithm. The obtained QSRR models were validated internally and externally, and they demonstrated satisfactory performance with key statistical parameters ranged from 0.844 to 0.914 for R2 and 0.696-0.898 for R2ext, respectively, indicating good predictive ability.

Innovative approaches to electrochemical oxidation of Bisphenol B in synthetic and complex water environments

The substitution of Bisphenol A (BPA) with Bisphenol B (BPB) has raised concerns due to BPB's increased environmental presence and its potential hazards. Despite the frequent detection in water environments, effective removal methods for BPB are still limited. This study hypothesizes that electrochemical oxidation (EO) can effectively degrade BPB and its by-products. To test this, EO was applied under various conditions, analyzing the role of anode material, current density, pH, and BPB concentration. The results revealed that BPB degradation followed pseudo-first-order kinetics, with boron-doped diamond (BDD) anode showing a rate constant 27 times higher than iridium oxide electrodes. After 180 min, BDD achieved 81.8 % mineralization of BPB. The remaining organic load was associated to easily biodegradable short-chain carboxylic acids. Additionally, the EO process was evaluated in different matrices, including drinking water, tap water, simulated municipal wastewater, and synthetic urine, to assess the impact of matrix complexity. Electrogenerated oxidants, such as hydroxyl radicals, sulfate radicals, and active chlorine, significantly enhanced BPB degradation rates in real water matrices. Energy consumption varied from 5.32 kWh m-3 in drinking water to 2.28 kWh m-3 in synthetic urine, demonstrating the role of matrix composition in EO efficiency. These findings show that EO is a promising technology for removing BPB and similar chemicals in real-world water matrices.

The combined use of biological investigations, bio chromatographic and in silico methods to solve the puzzle of badge and its derivative's toxicity

Bisphenol A diglycidyl ether (BADGE) is a pre-polymer of BPA widely used in manufacturing of epoxy resins and plastics; due to its high reactivity, unintended by-products, such as chlorinated and hydrolysed products, can reach the human body. This research integrates multiple approaches such as computational predictions, chromatographic experiments, biological assays, and human biomonitoring studies to comprehensively evaluate the toxicological profiles of the parent compound and its derivatives. In silico predictions were first utilized to estimate the toxicological properties and interactions of BADGE derivatives, providing insights into their bioactivity. Biomimetic liquid chromatography was then used to simulate membrane permeability and biodistribution, predicting how these chemicals might cross biological membranes and accumulate in tissues. In vitro experiments assessed cellular toxicity through viability assays, identifying BADGE·2HCl as the most cytotoxic derivative. Reactive Oxygen Species (ROS) production evaluation was performed to assess the oxidative stress induced by these compounds, revealing elevated ROS levels in cells exposed to BADGE and BADGE·2HCl with a consequent significant oxidative damage. Similarly, BADGE and BADGE·2HCl were able to induce cellular death by apoptosis activation. Human serum analysis in a population sample (N = 96), showed BADGE·2H2O as the most frequently detected metabolite, indicating a considerable human exposure and metabolic processes. The findings highlight a toxicity of BADGE derivatives similar to that of BADGE; BADGE·2HCl resulted particularly cytotoxic and BADGE·2H2O is the most frequent detected in human serum, underscoring the need for regulatory measures to mitigate potential health risks associated with these compounds.

Determination of the occurrence of and exposure to bisphenol A and its analogues in carbonated beverages and canned tuna using liquid chromatography - tandem mass spectrometry

Bisphenol A (BPA), a known endocrine disruptor, is commonly used in food containers and packaging. Recently, alternatives such as bisphenol AF (BPAF), bisphenol B (BPB), and bisphenol E (BPE) have been introduced to replace BPA. However, these substitutes have been reported to exhibit toxicity levels similar to BPA. In this study, we developed and validated a method for the analysis of trace bisphenols (BPA, BPAF, BPB, and BPE) in food using immunoaffinity column (IAC) clean-up. The method demonstrated satisfactory accuracy and precision. We applied this validated method to analyze 56 carbonated beverage samples and 30 canned tuna samples. In the carbonated beverages, average concentrations of BPA and BPAF were 0.4 and 0.2 μg kg-1, respectively. In canned tuna, BPA and BPAF were found at average concentrations of 22.2 and 0.7 μg kg-1, respectively, while BPB and BPE were not detected in any samples. Estimated exposure levels ranged from 0.13 to 0.18 ng kg bw-1 day-1 in the general population and from 205.2 to 232.0 ng kg bw-1 day-1 among consumers. The commercial IAC-based analytical method used in this study can contribute to the safety management of BPA, BPAF, BPB, and BPE.

Cytotoxic impacts of seven alternative bisphenols on human in vitro cellular models

Bisphenols (BPs), common in plastics, coatings, and resins, are under scrutiny for potential endocrine disruption. Despite banning bisphenol A (BPA), its perceived safer alternatives may still pose health risks, urging thorough studies on their toxicity mechanisms. This study aimed to investigate the cellular toxicity of the top seven most commonly used BPs, bisphenol S (BPS), bisphenol F (BPF), bisphenol AF (BPAF), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol B (BPB), bisphenol E (BPE) in eight different relevant human in vitro cell models: liver (HepaRG), intestinal (Caco-2), breast (T47D), brain (HMC-3), lungs (MRC-5), kidney (HEK293), endothelial (HMEC-1), and skin (HEK-001) cell lines. BPE manifested the highest cytotoxicity in Caco-2 cells, presenting an EC50 value of roughly 0.2 μM (95% confidence interval). In contrast, HEK293 and HepaRG cells demonstrated significant resilience to BPS (EC50 > 1000 μM). BPAF, BPP, and BPAP had consistently low EC50 values across cell lines (6-27.9 μM, 0.6-134.7 μM, and 3.6-178.8 μM), indicating elevated toxicity. After 24 h, all bisphenols adhered to nominal concentrations except BPAF, BPP, and BPS. BPP's concentration notably decreased (30.82 ± 5.53% of nominal value). The results revealed diverse effects of bisphenol analogs on different cell types. These findings emphasized the considerable cytotoxic potential of specific bisphenol analogs across various human cell models, underlining the necessity for a re-evaluation of their safety and regulatory standards.

Analysis and removal of bisphenols in recycled plastics using polyethylene glycol

This study examines the presence of bisphenol A (BPA), S (BPS), F (BPF), and M (BPM) in various recycled plastics readily available on the market (LDPE, HDPE, PET, and PP), in light of European Food Safety Authority (EFSA) limits. Twenty samples of different origin are analyzed, cleaning treatments are applied, and the migration potential of these bisphenols into food is studied. BPM is absent in all samples, but a post-consumer recycled LDPE sample reveals high bisphenol concentrations, raising concerns, reaching 8540 ng/g, 370 ng/g, and 29 ng/g of BPA, BPS, and BPF, respectively. Migration tests show substantial migration of these contaminants into food simulants. Using a cleaning treatment with polyethylene glycol (PEG 400) reduces BPA in LDPE, HDPE, PP, and PET samples by 95%, 99%, 97% and 28%, respectively, highlighting the importance of cleaning treatments across various polymers in plastic recycling. These findings not only protect food safety but addressing environmental challenges associated with plastic recycling.

Bisphenol S impairs mitochondrial function by targeting Myo19/oxidative phosphorylation pathway contributing to axonal and dendritic injury

Exposure to bisphenol S (BPS) is known to adversely affect neuronal development. As pivotal components of neuronal polarization, axons and dendrites are indispensable structures within neurons, crucial for the maintenance of nervous system function. Here, we investigated the impact of BPS exposure on axonal and dendritic development both in vivo and in vitro. Our results revealed that exposure to BPS during pregnancy and lactation led to a reduction in the complexity, density, and length of axons and dendrites in the prefrontal cortex (PFC) of offspring. Employing RNA sequencing technology to elucidate the underlying mechanisms of axonal and dendritic damage induced by BPS, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted a significant alteration in the oxidative phosphorylation (OXPHOS) pathway, essential for mitochondrial function. Subsequent experiments demonstrate BPS-induced impairment in mitochondrial function, including damaged morphology, decreased adenosine triphosphate (ATP) and superoxide dismutase (SOD) levels, and increased reactive oxygen species and malondialdehyde (MDA). These alterations coincided with the downregulated expression of OXPHOS pathway-related genes (ATP6V1B1, ATP5K, NDUFC1, NDUFC2, NDUFA3, COX6B1) and Myosin 19 (Myo19). Notably, Myo19 overexpression restored the BPS-induced mitochondrial dysfunction by alleviating the inhibition of OXPHOS pathway. Consequently, this amelioration was associated with a reduction in BPS-induced axonal and dendritic injury observed in cultured neurons of the PFC.

Into the toxicity potential of an array of parabens by biomimetic liquid chromatography, cell viability assessments and in silico predictions

Five parabens (PBs) i.e., Methylparaben (MP), Ethylparaben (EP), Isopropylparaben (iPrP), Isobutylparaben (iBuP), Benzylparaben (BzP), and their parent compound i.e., para-hydroxy Benzoic Acid (pHBA), were studied both in vitro and in silico. Specifically, we determined their retention on several both protein- (Human Serum Albumin and α1-acidic glycoprotein) and (phospho) lipid- (immobilized artificial membrane (IAM)) based biomimetic stationary phases to evaluate their penetration potential through the biomembranes and their possible distribution in the body. The IAM phases were based either on phosphatidylcholine (PC) analogues i.e., PC.MG and PC.DD2 or on sphingomyelin (SPH). We also assessed their viability effect on breast cancer cells (MCF-7) via MTT assay subjecting the cells to five different PB concentrations i.e., 100 μM, 10 μM, 1 μM, 0.1 μM and 0.01 μM. Finally, their pharmacokinetics and toxicity were assessed by the ADMET Predictor™ software. Isopropylparaben was found to be more active than 17β estradiol (E2) employed as positive control, on the screened cell line inducing cell proliferation up to 150 % more of untreated cells. Other analogues showed only a slight/moderate cell proliferation activity, with parabens having longer/branched side chain showing, on average, a higher proliferation rate. Significant linear direct relationships (for PC.DD2 r2 = 0.89, q2 = 0.86, for SPH r2 = 0.89, q2 = 0.85, for both P value < 0.05) were observed between the difference in proliferative effect between the readout and the control at 0.01 μM concentration and the retention on the IAM phases measured at pH 5.0 for all compounds but pHBA, which is the only analyte of the dataset supporting a carboxylic acid moiety. IAM affinity data measured at pH 7.0 were found to be related to the effective human jejunal permeability as predicted by the software ADMET® Predictor, which is relevant when PBs are added to pharmaceutical and food commodities.

Bisphenol F affects neurodevelopmental gene expression, mushroom body development, and behavior in Drosophila melanogaster

Bisphenol F (BPF) is a potential neurotoxicant used as a replacement for bisphenol A (BPA) in polycarbonate plastics and epoxy resins. We investigated the neurodevelopmental impacts of BPF exposure using Drosophila melanogaster as a model. Our transcriptomic analysis indicated that developmental exposure to BPF caused the downregulation of neurodevelopmentally relevant genes, including those associated with synapse formation and neuronal projection. To investigate the functional outcome of BPF exposure, we evaluated neurodevelopmental impacts across two genetic strains of Drosophila- w1118 (control) and the Fragile X Syndrome (FXS) model-by examining both behavioral and neuronal phenotypes. We found that BPF exposure in w1118 Drosophila caused hypoactive larval locomotor activity, decreased time spent grooming by adults, reduced courtship activity, and increased the severity but not frequency of β-lobe midline crossing defects by axons in the mushroom body. In contrast, although BPF reduced peristaltic contractions in FXS larvae, it had no impact on other larval locomotor phenotypes, grooming activity, or courtship activity. Strikingly, BPF exposure reduced both the severity and frequency of β-lobe midline crossing defects in the mushroom body of FXS flies, a phenotype previously observed in FXS flies exposed to BPA. This data indicates that BPF can affect neurodevelopment and its impacts vary depending on genetic background. Further, BPF may elicit a gene-environment interaction with Drosophila fragile X messenger ribonucleoprotein 1 (dFmr1)-the ortholog of human FMR1, which causes fragile X syndrome and is the most common monogenetic cause of intellectual disability and autism spectrum disorder.

Potential impacts of bisphenols on prostate cells: An overview of cytotoxicity, proliferation, oxidative stress, apoptosis, and ER-stress response activation

This study aimed to evaluate the toxic effects of Bisphenol A (BPA), Bisphenol F (BPF) and Bisphenol S (BPS) on PNT1A and PC-3 cells, focusing on their effects on endoplasmic reticulum (ER) stress and related pathways. PNT1A and PC-3 were treated with BPA, BPF and BPS at concentrations of 0.1, 1 and 10 μM for 48 h cytotoxicity, BrdU cell proliferation, ROS generation, apoptosis detection, gene expression analysis and Western blot analysis were performed. BPA induced proliferation and late apoptosis in PNT1A cells, whereas it induced both late apoptosis and early apoptosis in PC-3 cells. BPF and BPS induced late apoptosis in PC-3 cells. Increased ROS levels were observed in PNT1A cells exposed to 1-10 μM BPA. BPA, BPF and BPS increased the expression levels of ER stress-related genes in PNT1A cells. Furthermore, exposure to BPA increased the expression of ER stress-related CHOP/DDIT3 protein in PNT1A cells. These findings highlight the potential health risks associated with BPA, BPF and BPS exposure and emphasize the importance of investigating the underlying mechanisms by which these chemicals may affect human health. Further research is required to comprehensively understand the role of ER stress pathways in cellular responses to these substances.

Promoting Effect of Silver Oxide Nanoparticles on the Oxidation of Bisphenol B by Ferrate(VI)

Bisphenol B (BPB, 2,2-bis(4-hydroxyphenyl) butane), as a substitute for bisphenol A, has been widely detected in the environment and become a potential threat to environmental health. This work found that silver oxide nanoparticles (Ag2O) could greatly promote the removal of BPB by ferrate (Fe(VI)). With the presence of 463 mg/L Ag2O, the amount of Fe(VI) required for the complete removal of 10 μM BPB will be reduced by 70%. Meanwhile, the recyclability and stability of Ag2O have been verified by recycling experiments. The characterization results and in situ electrochemical analyses showed that Ag(II) was produced from Ag(I) in the Fe(VI)-Ag2O system, which has a higher electrode potential to oxidize BPB to enhance its removal. A total of 13 intermediates were identified by high-resolution mass spectrometry, and three main reaction pathways were proposed, including oxygen transfer, bond breaking, and polymerization. Based on the toxicity assessment through the ECOSAR program, it is considered that the presence of Ag2O reduced the toxicity of BPB oxidation intermediates to aquatic organisms. These results would deepen our understanding of the interaction between Fe(VI) and Ag2O, which may provide an efficient and environmentally friendly method for water and wastewater treatment.

Single and multispecies microalgae toxicological tests assessing the impact of several BPA analogues used by industry

BPA is a hazard for human and environmental health and recently BPA was added to the Candidate List of substances of very high concern by European Chemical Agency (ECHA). In accordance with this proposal, the authorities have encouraged the replacement of BPA by BPA analogues; however, little is known about the impact of these compounds on the environment. Due to this situation five BPA analogues (BPS, BPAP, BPAF, BPFL and BPC) were chosen in order to study their effects on marine primary producers. Three marine microalgae species (Phaeodactylum tricornutum, Tetraselmis suecica and Nannochloropsis gaditana) were selected for single and multispecies tests concerning the ecotoxicological effects of these BPA analogues. Microalgae were exposed to BPs over 72 h at different dosages (5, 20, 40, 80, 150 and 300 μM). Responses such as: growth, ROS production, cell complexity, cell size, autofluorescence of chlorophyll a, effective quantum yield of PSII and pigment concentrations were assessed at 24, 48 and 72 h. The results revealed that BPS and BPA showed lower toxicity to microalgae in comparison with BPFL > BPAF > BPAP and >BPC for the endpoints studied. N. gaditana was the least sensitive microalgae in comparison to P. tricornutum and T. suecica. However, a different trend was found in the multispecies tests where T. suecica dominated the microalgae community in relation to N. gaditana and P. tricornutum. The results of this work revealed for first time that present day BPA analogues are a threat and not a safe substitute for BPA in terms of the marine phytoplanktonic community. Therefore, the results of their impact on aquatic organisms should be shared.

Twelve natural estrogens and ten bisphenol analogues in eight drinking water treatment plants: Analytical method, their occurrence and risk evaluation

Bisphenol analogues (BPs) and natural estrogens (NEs) as two important groups of endocrine-disrupting compounds (EDCs) in drinking water treatment plants (DWTPs) have been hardly investigated except bisphenol A (BPA) and three major NEs including estrone (E1), 17β-estradiol (E2) and estriol (E3). In this study, a GC-MS analytical method was firstly established and validated for trace simultaneous determination of ten BPs and twelve NEs in drinking water, which included BPA, bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bsiphenol F (BPF), bsiphenol P (BPP), bisphenol S (BPS), bisphenol Z (BPZ), bisphenol AF (BPAF), bisphenol AP (BPAP), E1, E2, E3, 17α-estradiol (17α-E2), 2-hydroestrone (2OHE1), 16hydroxyestrone (16α-OHE1), 4-hydroestrone (4OHE1), 2-hydroxyesstradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 17-epiestriol (17epiE3), 16-epiestriol (16epiE3) and 16keto-estraiol (16ketoE2). This investigation showed that eighteen out of twenty-two targeted compounds were detected in drinking source waters of eight DWTPs with concentrations ranging from not detected to 142.8 ng/L. Although the conventional treatment process of DWTP could efficiently remove both BPs and NEs with respective removal efficiencies of 74.1%-90.9% and 74.5%-100%, BPA, BPS, BPE, BPZ, E1, 2OHE1, and 2OHE2 were found in the finished drinking waters. Chlorination could remove part of BPs and NEs, but the efficiency varied greatly with DWTP and the reason was unknown. In the finished drinking waters of eight DWTPs, the highest chemically calculated estrogen equivalence (EEQ) derived from BPs and NEs was up to 6.11 ngE2/L, which was over 22 times that could do harm to zebrafish, indicating a potential risk to human health. Given the fact that many chlorination products of BPs and NEs likely have higher estrogenic activities, the estrogenic effect of BPs and NEs in finished drinking water should be accurately examined urgently with the inclusion of BPs, NEs as well as their main chlorinated by-products. This study shed new light on the occurrence, removal, and potential estrogenic effects of BPs and NEs in DWTPs.

Combination of Bisphenol A and Its Emergent Substitute Molecules Is Related to Heart Disease and Exerts a Differential Effect on Vascular Endothelium

Plastic production, disposal, and recycling systems represent one of the higher challenges for the planet's health. Its direct consequence is the release of endocrine disruptors, such as bisphenol A (BPA), and its emerging substitute molecules, bisphenol F and S (BPF and BPS), into the environment. Consequently, bisphenols are usually present in human biological fluids. Since BPA, BPS, and BPF have structural analogies and similar hormonal activity, their combined study is urgently needed. The present manuscript studied the effect of the mixture of bisphenols (BPmix) in one of the world's largest human cohorts (NHANES cohort). Descriptive and comparative statistics, binomial and multinomial logistic regression, weighted quantile sum regression, quantile g-computation, and Bayesian kernel machine regression analysis determined a positive association between BPmix and heart disease, including confounders age, gender, BMI, ethnicity, Poverty/Income Ratio, and serum cotinine. Endothelial dysfunction is a hallmark of cardiovascular disease; thus, the average ratio of bisphenols found in humans was used to conduct murine aortic endothelial cell studies. The first results showed that BPmix had a higher effect on cell viability than BPA, enhancing its deleterious biological action. However, the flow cytometry, Western blot, and immunofluorescence assays demonstrated that BPmix induces a differential effect on cell death. While BPA exposure induces necroptosis, its combination with the proportion determined in the NHANES cohort induces apoptosis. In conclusion, the evidence suggests the need to reassess research methodologies to study endocrine disruptors more realistically.

Degradation and toxicity of bisphenol A and S during cold atmospheric pressure plasma treatment

Bisphenols are widely recognised as toxic compounds that potentially threaten the environment and public health. Here we report the use of cold atmospheric pressure plasma (CAP) to remove bisphenol A (BPA) and bisphenol S (BPS) from aqueous systems. Additionally, methanol was added as a radical scavenger to simulate environmental conditions. After 480 s of plasma treatment, 15-25 % of BPA remained, compared to > 80 % of BPS, with BPA being removed faster (-k_t = 3.4 ms^-1, half-life = 210 s) than BPS (-k_t = 0.15 ms^-1, half-life 4700 s). The characterisation of plasma species showed that adding a radical scavenger affects the formation of reactive oxygen and nitrogen species, resulting in a lower amount of ˙OH, H₂O₂, and NO₂^- but a similar amount of NO₃^-. In addition, a non-target approach enabled the elucidation of 11 BPA and five BPS transformation products. From this data, transformation pathways were proposed for both compounds, indicating nitrification with further cleavage, demethylation, and carboxylation, and the coupling of smaller bisphenol intermediates. The toxicological characterisation of the in vitro HepG2 cell model has shown that the mixture of transformation products formed during CAP is less toxic than BPA and BPS, indicating that CAP is effective in safely degrading bisphenols.

Gas chromatography-mass spectrometric determination of bisphenol residues by dispersive solid phase extraction followed by activated carbon spheres cleanup from fish feed samples

Bisphenols are known endocrine disruptors commonly utilized in food packaging and storage materials, which frequently come into touch with multiple food products packed in them. The bisphenols in fish feed and other feed materials for aquatic organisms are harmful. The consumption of such marine foods is hazardous. Hence, the feed of aquatic products needs to be verified for the presence of bisphenols. The present study was focused on developing and validating a rapid, selective, and sensitive method to quantify 11 bisphenols from the fish feed with dispersive solid-phase extraction, which was cleaned by an optimized amount of activated carbon spheres and silylated by N,O-bis(trimethylsilyl)trifluoro acetamide and analyzed by gas chromatography-mass spectrometry. The new method was rigorously tested and verified after carefully tuning various parameters affecting analyte recovery. Limit of detection (LOD) were set at 0.5-5 ng/g and limit of quantification (LOQ) at 1-10 ng/g, respectively, resulting in 95-114% recoveries. Interday and intraday precisions in terms of relative standard deviation were found to be less than 11%. The proposed approach was effectively applied in floating and sinking fish feeds. The obtained results showed that higher concentration of bisphenol A, followed by bisphenol TMC, and bisphenol M at a concentration of 256.10, 159.01, and 168.82 ng/g in floating feed and 88.04, 200.79, and 98.03 ng/g in sinking feed samples, respectively.

Sensitive determination of bisphenols in environmental samples by magnetic porous carbon solid-phase extraction combined with capillary electrophoresis

Bisphenol compounds exist widely in the environment and pose potential hazards to the environment and human health, which has aroused widespread concern. Therefore, there is an urgent need for an efficient and sensitive analytical method to enrich and determine trace bisphenols in environmental samples. In this work, magnetic porous carbon (MPC) was synthesized by one-step pyrolysis combined with a solvothermal method for magnetic solid-phase extraction of bisphenols. The structural properties of MPC were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and saturation magnetization analysis. Its adsorption properties were evaluated by adsorption kinetics and adsorption isotherm studies. By optimizing the magnetic solid-phase extraction and capillary electrophoresis separation conditions, a capillary electrophoresis separation and detection method for four bisphenols was successfully constructed. The results showed that the detection limits of the proposed method for the four bisphenols were 0.71-1.65 ng/mL, the intra-day and inter-day precisions were 2.27-4.03% and 2.93-4.42%, respectively, and the recoveries were 87.68%-108.0%. In addition, the MPC could be easily recycled and utilized, and even if the magnetic solid-phase extraction was repeated 5 times, the extraction efficiency could still be kept above 75%.

Toxicity overview of endocrine disrupting chemicals interacting in vitro with the oestrogen receptor

The oestrogen receptor (ER) from the nuclear receptor family is involved in different physiological processes, which can be affected by multiple xenobiotics. Some of these compounds, such as bisphenols, pesticides, and phthalates, are widespread as consequence of human activities and are commonly present also in human organism. Xenobiotics able to interact with ER and trigger a hormone-like response, are known as endocrine disruptors. In this review, we aim to summarize the available knowledge on products derived from human industrial activity and other xenobiotics reported to interact with ER. ER-disrupting chemicals behave differently towards oestrogen-dependent cell lines than endogenous oestradiol. In low concentrations, they stimulate proliferation, whereas at higher concentrations, are toxic to cells. In addition, most of the knowledge on the topic is based on individual compound testing, and only a few studies assess xenobiotic combinations, which better resemble real circumstances. Confirmation from in vivo models is lacking also.

Combined Toxic Effects of BPA and Its Two Analogues BPAP and BPC in a 3D HepG2 Cell Model

Bisphenol A (BPA) is one of the most commonly used substances in the manufacture of various everyday products. Growing concerns about its hazardous properties, including endocrine disruption and genotoxicity, have led to its gradual replacement by presumably safer analogues in manufacturing plastics. The widespread use of BPA and, more recently, its analogues has increased their residues in the environment. However, our knowledge of their toxicological profiles is limited and their combined effects are unknown. In the present study, we investigated the toxic effects caused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP and BPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed that BPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP and BPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC) decreased cell viability in a dose-dependent manner, but the significant difference was only observed for the combination of BPA/BPC (both at 40 µM). After 96-h exposure, none of the BPs studied affected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cell viability in a dose-dependent manner that was significant for the combination of 4 µM BPA and 4 µM BPAP. None of the BPs and their binary mixtures studied affected the surface area and growth of spheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggered oxidative stress, as measured by the production of reactive oxygen species and malondialdehyde, at both exposure times. Overall, the results suggest that it is important to study the effects of BPs as single compounds. It is even more important to study the effects of combined exposures, as the combined effects may differ from those induced by single compounds.

Binding sites in the epidermal growth factor receptor are responsible for bisphenol S effects on trophoblast cell invasion

Bisphenol S (BPS) is an endocrine disrupting chemical and the second most abundant bisphenol detected in humans. We have recently demonstrated that in utero exposure to BPS reduces human placenta cell fusion by interfering with epidermal growth factor (EGF)-dependent EGF receptor (EGFR) activation. Our previous work suggests that this occurs via binding of BPS to the extracellular domain of EGFR. However, whether BPS directly binds to EGFR has not been confirmed. We evaluated the binding ability of BPA, BPF and BPS to EGFR to determine whether EGFR binding is a unique attribute of BPS. To test these hypotheses, we first exposed HTR-8/SVneo cells to BPS, BPA, or BPF, with or without EGF. When co-exposed to EGF, BPS, but not BPA nor BPF, reduced EGFR phosphorylation by ∼60%, demonstrating that only BPS can interfere with EGF-dependent EGFR activation. As this indicates that BPS binding to the extracellular domain is responsible for its effect, we performed a computational search for putative binding sites on the EGFR extracellular domain, and performed ligand docking of BPS, BPA, and BPF at these sites. We identified three sites where polar interactions between positively charged residues and the sulfonyl group of BPS could lead binding selectivity over BPA and BPF. To test whether EGFR mutations at the predicted BPS binding sites (Arg255, Lys454, and Arg297) could prevent BPS's interference on EGFR activation, mutations for each EGFR target amino acids (R255A, R297A, and K454A) were introduced. For variants with R297A or K454A mutations, BPS did not affect EGF-mediated EGFR phosphorylation or EGFR-mediated cell invasion, suggesting that these residues are needed for the BPS antagonism effect on EGFR. In conclusion, BPS, but not BPA or BPF, interferes with EGFR-mediated trophoblast cell functions through binding at Arg297 and Lys454 amino acid residues in the extracellular domain of EGFR.

Evaluation of toxicological effects of bisphenol S with an in vitro human bone marrow mesenchymal stem cell: Implications for bone health

As the use of bisphenol A (BPA) has been restricted in consumer products, bisphenol S (BPS) is one major alternative to BPA for various materials, leading to growing concerns about its health risks in human beings. However, little is known about the toxic effects of BPS on bone health. We employed human bone marrow mesenchymal stem cells (hBMSCs) for the in vitro assessment of BPS on cell proliferation, differentiation, and self-renewal. Our study revealed that BPS at concentrations of 10^-10-10^-7 M increased cell viability but induced the morphological changes of hBMSCs. Moreover, BPS decreased ROS generation and increased Nrf2 expression. Furthermore, BPS not only activated ERα/β expression but also increased β-catenin expression and induced the replicative senescence of hBMSCs. Furthermore, we found that the upregulation of β-catenin induced by BPS was mediated, in part, by ER signaling. Overall, our results suggested BPS exposure caused the homeostatic imbalance of hBMSCs.

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.

Smart Portable Device Based on the Utilization of a 2D Disposable Paper Stochastic Sensor for Fast Ultrasensitive Screening of Food Samples for Bisphenols

Since the determination of the high toxicity of bisphenol A, alternative structures for bisphenols have been synthesized, resulting in bisphenols C, E, F, S, and Z. These bisphenols have replaced bisphenol A in plastic bottles, toys, and cans used for preserving food. Later, the toxicity and negative effects of all of these bisphenols on people's health were proven. Therefore, there is a need for a fast ultrasensitive screening method that is able to detect the presence of these bisphenols in any condition directly from food samples. This paper presented a disposable device based on the utilization of a 2D disposable paper stochastic sensor for the fast ultrasensitive screening of food samples for bisphenols A, C, E, F, S, and Z. The 2D disposable sensor was obtained by the deposition of graphene and silver nanolayers on paper using cold plasma. Furthermore, the active side of the sensor was modified using 2,3,7,8,12,13,17,18-octaethyl-21H,23H Mn porphyrin. The limits of quantification of these bisphenols were 1 fmol L^-1 for bisphenols C and E, 10 fmol L^-1 for bisphenols A and F, 10 pmol L^-1 for bisphenol S, and 1 pmol L^-1 for bisphenol Z. The recoveries of these bisphenols in milk, canned fruits, vegetables, and fish were higher than 99.00% with RSD (%) values lower than 1.50%.

Dietary zinc deficient condition increases the Bisphenol A toxicity in diabetic rat testes

Bisphenol A (BPA) is a widely used endocrine disrupter that causes male reproductive dysfunction in humans and rodents. Diabetes-induced hyperglycemia alters spermatogenesis and antioxidant status, which negatively impacts male fertility in adults. Zinc (Zn) deficiency is a global health concern maintaining the testicular structure and functions in developing gonads. The present experiment was designed to investigate the role of Zn deficiency on BPA-induced germ cell and male gonadal toxicity in diabetic conditions. Rats were randomly divided into eight different groups - control (normal feed and water), BPA (10 mg/kg/day), ZDD (fed with a Zn-deficient diet), DIA (diabetic), BPA+ZDD, BPA+DIA, ZDD+DIA and BPA+ZDD+DIA for four weeks. Animals' body and organ weight, sperm count, motility and sperm morphology were examined; testes and epididymis histopathology were investigated. Testicular DNA damage and sperm apoptosis were evaluated by halo and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays respectively. Testicular catalase and octamer-binding transcription factor 4 (OCT4) expressions were evaluated by western blot analysis. The present results demonstrated that dietary Zn-deficient condition significantly increased the BPA-induced testicular, epididymal and sperm toxicity in diabetic rats due to hypogonadism, increased sperm abnormalities, epididymis, testicular structure and DNA damages, sperm apoptosis as well as decreased testicular catalase and OCT4 expressions. The present results revealed that dietary Zn-deficient condition exacerbated the BPA-induced testicular and epididymal toxicity as well as perturbed the general male reproductive health in diabetic rats.

Adaptation and Resistance: How Bacteroides thetaiotaomicron Copes with the Bisphenol A Substitute Bisphenol F

Bisphenols are used in the process of polymerization of polycarbonate plastics and epoxy resins. Bisphenols can easily migrate out of plastic products and enter the gastrointestinal system. By increasing colonic inflammation in mice, disrupting the intestinal bacterial community structure and altering the microbial membrane transport system in zebrafish, bisphenols seem to interfere with the gut microbiome. The highly abundant human commensal bacterium Bacteroides thetaiotaomicron was exposed to bisphenols (Bisphenol A (BPA), Bisphenol F (BPF), Bisphenol S (BPS)), to examine the mode of action, in particular of BPF. All chemicals caused a concentration-dependent growth inhibition and the half-maximal effective concentration (EC50) corresponded to their individual logP values, a measure of their hydrophobicity. B. thetaiotaomicron exposed to BPF decreased membrane fluidity with increasing BPF concentrations. Physiological changes including an increase of acetate concentrations were observed. On the proteome level, a higher abundance of several ATP synthase subunits and multidrug efflux pumps suggested an increased energy demand for adaptive mechanisms after BPF exposure. Defense mechanisms were also implicated by a pathway analysis that identified a higher abundance of members of resistance pathways/strategies to cope with xenobiotics (i.e., antibiotics). Here, we present further insights into the mode of action of bisphenols in a human commensal gut bacterium regarding growth inhibition, and the physiological and functional state of the cell. These results, combined with microbiota-directed effects, could lead to a better understanding of host health disturbances and disease development based on xenobiotic uptake.

Parabens Permeation through Biological Membranes: A Comparative Study Using Franz Cell Diffusion System and Biomimetic Liquid Chromatography

Parabens (PBs) are used as preservatives to extend the shelf life of various foodstuffs, and pharmaceutical and cosmetic preparations. In this work, the membrane barrier passage potential of a subset of seven parabens, i.e., methyl-, ethyl-, propyl- isopropyl, butyl, isobutyl, and benzyl paraben, along with their parent compound, p-hydroxy benzoic acid, were studied. Thus, the Franz cell diffusion (FDC) method, biomimetic liquid chromatography (BLC), and in silico prediction were performed to evaluate the soundness of both describing their permeation through the skin. While BLC allowed the achievement of a full scale of affinity for membrane phospholipids of the PBs under research, the permeation of parabens through Franz diffusion cells having a carbon chain > ethyl could not be measured in a fully aqueous medium, i.e., permeation enhancer-free conditions. Our results support that BLC and in silico prediction alone can occasionally be misleading in the permeability potential assessment of these preservatives, emphasizing the need for a multi-technique and integrated experimental approach.

Bisphenol A Analogs Induce Cellular Dysfunction in Human Trophoblast Cells in a Thyroid Hormone Receptor-Dependent Manner: In Silico and In Vitro Analyses

Bisphenol A (BPA) and its analogs are frequently detected in human daily necessities and environmental media. Placental thyroid hormone plays an important role in fetal development. Herein, we followed the adverse outcome pathway (AOP) to explore the toxic mechanisms of BPA and its analogs toward placental thyroid hormone receptor (TR). First, the TOX21 database was used, and the interactions between BPA analogs and the ligand-binding domains (LBDs) of two subtypes of TR (TRα and TRβ) were subjected to in silico screening using molecular docking (MD) and molecular dynamics simulation (MDS). Fluorescence spectra and circular dichroism (CD) showed that BPA and its analogs interfere with TRs as a molecular initiation event (MIE), including static fluorescence quenching and secondary structural content changes in TR-LBDs. Key events (KEs) of the AOP, including the toxicity induced in placental chorionic trophoblast cells (HTR-8/SVneo) by an inverted U-shaped dose effect and changes in ROS levels, were tested in vitro. BPA, BPB, and BPAF significantly changed the expression level of TRβ, and only BPAF significantly downregulated the expression level of TRα. In conclusion, our study contributes to the health risk assessment of BPA and its analogs regarding placental adverse outcomes (AOs).

Monitoring of Pollutants Content in Bottled and Tap Drinking Water in Italy

The concentration levels of thirteen organic pollutants and selected heavy metals were investigated in 40 plastics bottled and tap water samples. Some of the selected contaminants have an ascertained or suspected endocrine disrupting activity, such as Bisphenol A (BPA) and its analogs, and Bis 2-ethylhexyl phthalate (DEHP), which are used by industries as plasticizers. The most frequently detected pollutants were Bisphenol AF (BPAF) (detection frequency (DF) = 67.5%, mean 387.21 ng L⁻¹), DEHP (DF = 62.5%, mean 46.19 µg L⁻¹) and BPA (DF = 60.0%, mean 458.57 ng L⁻¹), with higher concentration levels found in tap waters. Furthermore, a possible level of exposure to thirteen pollutants via drinking water intake was calculated. Our findings show that, even though the occurrence of contaminants and heavy metals in drinking waters does not pose an immediate, acute health risk for the population, their levels should be constantly monitored and “hard-wired” into everyday practice. Indeed, the health impact to the continuous and simultaneous intake of a huge variety of xenobiotics from various sources by humans is complex and still not fully understood.

Toxicity screening of bisphenol A replacement compounds: cytotoxicity and mRNA expression in LMH 3D spheroids

Previously, we showed that the chicken LMH cell line cultured as 3D spheroids may be a suitable animal free alternative to primary chicken embryonic hepatocytes (CEH) for avian in vitro chemical screening. In this study, cytotoxicity and mRNA expression were determined in LMH 3D spheroids following exposure to bisphenol A (BPA), five BPA replacement compounds (BPF, TGSH, DD-70, BPAF, BPSIP), and 17β estradiol (E2). Results were compared to an earlier study that evaluated the same endpoints for these chemicals in CEH. BPA and the replacement compounds had LC50 values ranging from 16.6 to 81.8 μM; DD-70 and BPAF were the most cytotoxic replacements (LC50 = 17.23 ± 4.51 and 16.6 ± 4.78 μM). TGSH and DD-70 modulated the greatest number of genes, although fewer than observed in CEH. Based on the expression of apovitellenin and vitellogenin, BPAF was the most estrogenic compound followed by BPF, BPSIP, and BPA. More estrogen-responsive genes were modulated in LMH spheroids compared to CEH. Concentration-dependent gene expression revealed that DD-70 and BPAF altered genes related to lipid and bile acid regulation. Overall, cytotoxicity and clustering of replacements based on gene expression profiles were similar between LMH spheroids and CEH. In addition to generating novel gene expression data for five BPA replacement compounds in an in vitro avian model, this research demonstrates that LMH spheroids may represent a useful animal free alternative for avian toxicity testing.

Recent developments in photocatalysis of industrial effluents ։ A review and example of phenolic compounds degradation

Industrial expansion and increased water consumption have created water scarcity concerns. Meanwhile, conventional wastewater purification methods have failed to degrade recalcitrant pollutants efficiently. The present review paper discusses the recent advances and challenges in photocatalytic processes applied for industrial effluents treatment, with respect to phenolic compounds degradation. Key operational parameters including the catalyst loading, light intensity, initial pollutants concentration, pH, and type and concentrations of oxidants are evaluated and discussed. Compared to the other examined controlling parameters, pH has the highest effect on the photo-oxidation of contaminants by means of the photocatalyst ionization degree and surface charge. Furthermore, major phenolic compounds derived from industrial sources are comprehensively presented and the applicability of photocatalytic processes and the barriers in practical applications, including high energy demand, technical challenges, photocatalyst stability, and recyclability have been explored. The importance of energy consumption and operational costs for realistic large-scale processes are also discussed. Finally, research gaps in this area and the suggested direction for improving degradation efficiencies in industrial applications are presented. In the light of these premises, selective degradation processes in real water matrices such as untreated sewage are proposed.

Men´s reproductive alterations caused by bisphenol A and its analogues: a review

Male reproductive functions are an important area affecting men´s overall health and well-being. However, during the last years, there has been observed increasing incidence of male reproductive issues. The radical growth has been recorded parallelly with a massive expanse of industrialization and agricultural chemigation. Many groups of experts have begun to identify several potential factors and substances that may have adverse effects on men´s reproductive health. Since then, xenobiotics have become a major concern of many scientific studies. There is evidence that most of them have multigenerational and transgenerational effects on reproductive health, which is a serious problem for our population. Bisphenol A could be considered as one of the most studied endocrine disruptors. Until now, several negative effects of bisphenol A were associated with reduced weight testes, histological alterations, impairment spermatogenesis, and steroidogenesis as well as with testes or prostate cancer. Due to convincing evidence, bisphenol A has been started to replace by its analogues such as bisphenol B, S, F, in order to eliminate and suppress the risk of exposure to bisphenol A. However, it seems that a lack of toxicological analyses allows using of these hazardous substances in daily life. Their harmful effect was confirmed by the animal in vitro and in vivo models, while the epidemiological studies monitoring the impact of bisphenol analogues on men's reproductive health are markedly limited. This review provides information about the effects of bisphenol on reproductive health in men. At the same time, it is focused on physiological aspects of sperm viability, steroid hormone secretion, sperm motility, or testes histology in relation to bisphenols exposure.

Bisphenol AF exposure causes fasting hyperglycemia in zebrafish (Danio rerio) by interfering with glycometabolic networks

Bisphenol AF (BPAF), one of the main alternatives to bisphenol A, has been frequently detected in various environmental media, including the human body, and is an emerging contaminant. Epidemiological investigations have recently shown the implications of exposure to BPAF in the incidence of diabetes mellitus in humans, indicating that BPAF may be a potential diabetogenic endocrine disruptor. However, the effects of BPAF exposure on glucose homeostasis and their underlying mechanisms in animals remain largely unknown, which may limit our understanding of the health risks of BPAF. To this end, zebrafish (Danio rerio), an emerging and valuable model in studying animal glycometabolism and diabetes, were exposed to environmentally relevant concentrations (5 and 50 μg/L) and 500 μg/L BPAF for 28 d. Several key toxicity endpoints of blood glucose metabolism were detected in our study, and the results showed significantly increased fasting blood glucose levels, hepatic glycogen contents and hepatosomatic indexes and decreased muscular glycogen contents in the BPAF-exposed zebrafish. The results of quantitative real-time PCR showed the abnormal expression of genes involved in glycometabolic networks, which might promote hepatic gluconeogenesis and inhibit glycogenesis and glycolysis in the muscle and/or liver. Furthermore, the failure of insulin regulation, including plasma insulin deficiency and impaired insulin signaling pathways in target tissues, may be a potential mechanism underlying BPAF-induced dysfunctional glycometabolism. In summary, our results provide novel in vivo evidence that BPAF can cause fasting hyperglycemia by interfering with glycometabolic networks, which emphasizes the potential health risks of environmental exposure to BPAF in inducing diabetes mellitus.

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.

Bisphenol S leads to cytotoxicity-induced antioxidant responses and oxidative stress in isolated rainbow trout (Oncorhyncus mykiss) hepatocytes

BACKGROUND

Bisphenol S (BPS) is a chemical compound that is utilized in the plastic industry as an alternative to bisphenol A (BPA). The toxic effects of BPS in fish is less known and limited. Therefore, in the present study, the influence of BPS on rainbow trout (Oncorhyncus mykiss) hepatocytes in vitro was investigated.

METHODS AND RESULTS

For this purpose the fish hepatocytes were isolated, and then the cultured cells were treated with increasing concentrations of BPS (0, 15.63, 31.25, 62.50, 125, 250, and 500 µM) for 24 h. The cytotoxic impact of BPS was determined in the culture media using lactate dehydrogenase assay and then, the antioxidant defence indicators were assayed. The results showed that concentration-dependent increases were observed in the percentage of cytotoxicity. The superoxide dismutase activity was reduced, while the catalase and glutathione peroxidase activity increased with all of the BPS concentrations. The glutathione S-transferase (GST) activity significantly increased after a BPS concentration of 31.25 µM or higher, while GST Theta 1-1 activity was decreased by the same concentrations of BPS. The reduced glutathione content significantly decreased with a BPS concentration of 31.25 µM or higher, and the malondialdehyde content increased after BPS concentrations of 125, 250, and 500 µM.

CONCLUSIONS

The findings determined herein suggested that BPS causes cytotoxicity in fish hepatocytes and can lead to oxidative stress, resulting hepatotoxic in fish. Thus, the utilization of BPS instead of BPA as safe alternative in industry should be re-evaluated in the future for environmental health.

The occurrence of selected endocrine-disrupting chemicals in water and sediments from an urban lagoon in Southern Italy

Endocrine-disrupting chemicals (EDCs) are agents able to exert perturbation toward the endocrine system via a broad array of signalling pathways. Some EDCs are released into the environment as a result of antropogenic activities. Analytical surveillance plays a critical role in investigating the prevalence of such chemicals in environmental samples. A study was carried out in a lagoon in Southern Italy, a water basin relates to the sea through a mouth channel, making this water body a "dynamic environment". The screening of fourteen EDCs in surface waters and sediments, includes a fast and cost-effective sample preparation, based on a solid-liquid (sediments) and liquid-liquid (surface waters) extraction and a chromatographic analysis by liquid chromatography tandem UV and fluorescence detection. Only four chemicals out the fourteen investigated EDCs were detected in both matrices with a frequency higher than 60%. The average concentrations of the single EDC were higher in sediments (730-155.000 ng kg^-1  dw) than in surface waters (132-28.000 ng L^-1 ). Limited to the assayed EDCs, the ecosystem has a low risk regarding to the conservation of biodiversity of the animal species living thereby, since the total estrogenic activity does not exceed 1 ng L^-1 . PRACTITIONER POINTS: Occurrence of selected EDCs was investigated in an Italian lagoon in Southern Italy. BPAF, BADGE, and BPA were the most frequently and highly detected compounds in both waters and sediments. Concentration levels were greater in the sediment than in water samples. Low risk for the ecosystem biodiversity concerning investigated EDCs.

A comprehensive review on the analytical method, occurrence, transformation and toxicity of a reactive pollutant: BADGE

Bisphenol A diglycidyl ether (BADGE)-based epoxy resin is one of the most widely used epoxy resins with an annual production amount of several million tons. Compared with all other legacy or emerging organic compounds, BADGE is special due to its toxicity and high reactivity in the environment. More and more studies are available on its analytical methods, occurrence, transformation and toxicity. Here, we provided a comprehensive review of the current BADGE-related studies, with focus on its production, application, available analytical methods, occurrences in the environment and human specimen, abiotic and biotic transformation, as well as the in vitro and in vivo toxicities. The available data show that BADGE and its derivatives are ubiquitous environmental chemicals and often well detected in human specimens. For their analysis, a water-free sample pretreatment should be considered to avoid hydrolysis. Additionally, their complex reactions with endogenous metabolites are areas of great interest. To date, the monitoring and further understanding of their transport and fate in the environment are still quite lacking, comparing with its analogues bisphenol A (BPA) and bisphenol S (BPS). In terms of toxicity, the summary of its current studies and Environmental Protection Agency (EPA) ToxCast toxicity database suggests BADGE might be an endocrine disruptor, though more detailed evidence is still needed to confirm this hypothesis in in vivo animal models. Future study of BADGE should focus on its metabolic transformation, reaction with protein and validation of its role as an endocrine disruptor. We believe that the elucidation of BADGEs can greatly enhance our understandings of those reactive compounds in the environment and human.

Determination of 18 bisphenols in aqueous and biomass phase of high rate algal ponds: Development, validation and application

High rate algal ponds (HRAP) are an alternative to conventional wastewater treatment with the potential for wastewater and biomass reuse. In this study, we report the development and validation of methods for analysing 18 bisphenols (BPs) in the aqueous and biomass phase of HRAP. For aqueous phase samples, obtained LLOQ ranged from 10 to 30 ng/L, and recoveries from 78% to 106%. The relative expanded uncertainty was highest at the lowest spiking level (100 ng/L) and ranged from 27% to 66% (BPA), while for the biomass, the LLOQ ranged from 25 to 75 ng/g dw, recoveries from 84% to 103%. The uncertainty ranged from 16% to 37% (BPA). On average, the influent contained 329, 144, and 21 ng/L of BPA, BPS and 4,4'-BPF, and the effluent 69 ng/L, 94 ng/L and <LLOQ, respectively. Only BPA was quantified in the algal biomass. The average removal of BPA was 80%, whereas the removal efficiency of BPS was 32%. To our knowledge, this is the first study analysing a wide range of BPs in both aqueous and biomass phase of HRAP treating real wastewater.

Toxicity Screening of Bisphenol A Replacement Compounds: Cytotoxicity and mRNA Expression in Primary Hepatocytes of Chicken and Double-Crested Cormorant

A market for bisphenol A (BPA) replacement compounds has emerged as a result of restrictions on the use of BPA. Some of these compounds have been detected in the environment; however, little is known about their toxicological properties. In the present study, an avian in vitro toxicogenomic approach was used to compare the effects of 5 BPA alternatives. Cell viability and mRNA expression were compared in primary embryonic hepatocytes of chicken (CEH) and double-crested cormorant (DCEH) exposed to 4,4'-(propane-2,2-diyl) diphenol (BPA), bis (4-hydroxyphenyl) methane (BPF), bis (3-allyl-4-hydroxyphenyl) sulfone (TGSH), 7-bis (4-hydroxyphenylthio)-3,5-dioxaheptane (DD-70), 2,2-bis (4-hydroxyphenyl) hexafluoropropane (BPAF), and 4-hydroxyphenyl 4-isoprooxyphenylsulfone (BPSIP). Changes in gene expression were determined using 2 polymerase chain reaction (PCR) arrays: 1) species-specific ToxChips that contain genes representing toxicologically relevant pathways, and 2) chicken-specific AestroChip that measures estrogen responsive genes. In CEH and DCEH, BPA alternatives TGSH, DD-70, and BPAF were most cytotoxic. Some of the replacement compounds changed the expression of genes related to xenobiotic metabolism, bile acid, and cholesterol regulation. The rank order based on the number of genes altered on the chicken ToxChip array was TGSH > DD-70 > BPAF = BPF > 17β estradiol (E2) > BPSIP > BPA. On the cormorant ToxChip array, BPSIP altered the greatest number of genes. Based on the chicken AestroChip data, BPSIP and BPF were slightly estrogenic. These results suggest that the replacement compounds have comparable or even greater toxicity than BPA and act via different mechanisms. Environ Toxicol Chem 2021;40:1368-1378. © 2021 Her Majesty the Queen in Right of Canada. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Consequences of the exposure to bisphenol A in cell membrane models at the molecular level and hamster ovary cells viability

The inadequate disposal and the difficulty in its removal from water treatment systems have made the endocrine disruptor bisphenol A (BPA) a significant hazard for humans and animals. The molecular-level mechanisms of BPA action are not known in detail, which calls for systematic investigations using cell membrane models. This paper shows that BPA affects Langmuir monolayers and giant unilamellar vesicles (GUVs) of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) used as membrane models, in a concentration-dependent manner and with effects that depend on BPA aggregation. BPA increases DPPC monolayer fluidity in surface pressure isotherms upon interacting with the headgroups through hydrogen bonding, according to polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). In DPPC GUVs, BPA induced wrinkling and distortion in the spherical shape of the vesicles, but this was only observed for fresh solutions where it is not aggregated. BPA also decreased the viability of hamster ovary cells (CHO) in in vitro experiments. In contrast, aged, aggregated BPA solutions did not affect the GUVs and even increased CHO viability. These results may be rationalized in terms of size-dependent effects of BPA, which may be relevant for its endocrine-disrupting effects.

In vitro effects of bisphenol F on antioxidant system indicators in the isolated hepatocytes of rainbow trout (Oncorhyncus mykiss)

Bisphenol F (BPF) has been used frequently in the plastics industry and the production of daily consumer products as an alternative to bisphenol A (BPA). It was aimed herein to determine the cytotoxic effects of BPF on hepatocytes isolated from the liver of rainbow trout (Oncorhyncus mykiss) using lactate dehydrogenase (LDH) assay and antioxidant defence system indicators. The cultured hepatocytes were exposed to seven concentrations (0, 15.63, 31.25, 62.50, 125, 250, and 500 µM) of BPF for 24 h. According to the LDH assay, the percentage of cytotoxicity was increased dose dependently in the cells. The malondialdehyde content, which is indicative of lipid peroxidation, was increased significantly at BPF concentrations between 15.63 and 250 µM, whereas it remained unchanged with a concentration of 500 µM. The activities of superoxide dismutase were increased, while those of catalase were decreased with all of the BPF concentrations. Elevated levels of reduced glutathione content were determined with BPF concentrations between 15.63 and 250 µM, but decreased significantly with a concentration of 500 µM. Significant increases in the activities of the glutathione peroxidase were found in hepatocytes treated with BPF at concentrations of 31.25 to 500 µM. GST activity was only significantly increased with a BPF concentration of 250 µM. The results showed that the toxic mechanism of BPF was mainly based on cell membrane damage and oxidative stress, which have an influence on antioxidant defences. Therefore, BPF should be reconsidered as a safe alternative instead of BPA in the manufacturing of industrial or daily products.

A new approach based on inversion of a partial least squares model searching for a preset analytical target profile. Application to the determination of five bisphenols by liquid chromatography with diode array detector

The paper shows a procedure for selecting the control method parameters (factors) to obtain a preset 'analytical target profile' when a liquid chromatographic technique is going to be carried out for the simultaneous determination of five bisphenols (bisphenol-A, bisphenol-S, bisphenol-F, bisphenol-Z and bisphenol-AF), some of them regulated by the European Union. The procedure has three steps. The first consists of building a D-optimal combined design (mixture-process design) for the control method parameters, which are the composition of the ternary mobile phase and its flow rate. The second step is to fit a PLS2 model to predict six analytical responses (namely, the resolution between each pair of consecutive peaks, and the initial and final chromatographic time) as a function of the control method parameters. The third final step is the inversion of the PLS2 model to obtain the conditions needed for attaining a preset analytical target profile. The computational inversion of the PLS2 prediction model looking for the Pareto front of these six responses provides a set of experimental conditions to conduct the chromatographic determination, specifically 22% of water, mixed with 58% methanol and 20% of acetonitrile, keeping the flow rate at 0.66 mL min^-1. These conditions give a chromatogram with retention times of 2.180, 2.452, 2.764, 3.249 and 3.775 min for BPS, BPF, BPA, BPAF and BPZ, respectively, and excellent resolution among all the chromatographic peaks. Finally, the analytical method is validated under the selected experimental conditions, in terms of trueness and precision. In addition, the detection capability for the five bisphenols were: 596, 334, 424, 458 and 1156 μg L^-1, with probabilities of false positive and of false negative equal to 0.05.

Sex-specific oxidative damage effects induced by BPA and its analogs on primary hippocampal neurons attenuated by EGCG

BPA analogs, including bisphenol S (BPS) and bisphenol B (BPB), have been used to replace BPA since it was banned to be added. To investigate whether BPA and its analogs cause oxidative damage effects on primary hippocampal neurons of rats, reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), mitochondrial membrane potential (MMP), apoptosis and cell viability assays were conducted after hippocampal neurons exposure to different concentrations of BPA, BPS, and BPB (1, 10, 100 nM and 1, 10, 100 μM). Moreover, the effects of EGCG (5 and 6 μM for male and female, respectively) added on neurons exposed to BPA were assessed. Results showed that 24 h exposure to these bisphenols (BPs) could increase the levels of ROS and contents of MDA, but reduce the activity of SOD significantly. A decline of cell viabilities accompanied with the increasing of apoptosis rates was observed after 7 d exposure to BPs and the reduction of MMP was also observed after 7 d exposure to BPA. Interestingly, BPS has the lower toxicity to hippocampal neurons compared with BPA and BPB. Non-monotonic dose-effect relationships between the concentrations of BPs and the cytotoxic effects were observed, and the effects of BPs on male hippocampal neurons are greater than those of female ones in general. While EGCG can protect neurons free of oxidative damages. In conclusion, the results suggest that BPs may induce sex-specific neurotoxic effects involving oxidative stress, which can be attenuated by EGCG, and males are more sensitive to BPs than females.