Potential Endocrine Disruptors Research Articles

Cumulative Exposure to Phthalates and Their Alternatives and Associated Female Reproductive Health: Body Burdens, Adverse Outcomes, and Underlying Mechanisms.

The global birth rate has recently shown a decreasing trend, and exposure to environmental pollutants has been identified as a potential factor affecting female reproductive health. Phthalates have been widely used as plasticizers in plastic containers, children's toys, and medical devices, and their ubiquitous presence and endocrine-disrupting potential have already raised particular concerns. Phthalate exposure has been linked to various adverse health outcomes, including reproductive diseases. Given that many phthalates are gradually being banned, a growing number of phthalate alternatives are becoming popular, such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), di(2-ethylhexyl) adipate (DEHA), and di(2-ethylhexyl) terephthalate (DEHTP), and they are beginning to have a wide range of environmental effects. Studies have shown that many phthalate alternatives may disrupt female reproductive function by altering the estrous cycle, causing ovarian follicular atresia, and prolonging the gestational cycle, which raises growing concerns about their potential health risks. Herein, we summarize the effects of phthalates and their common alternatives in different female models, the exposure levels that influence the reproductive system, and the effects on female reproductive impairment, adverse pregnancy outcomes, and offspring development. Additionally, we scrutinize the effects of phthalates and their alternatives on hormone signaling, oxidative stress, and intracellular signaling to explore the underlying mechanisms of action on female reproductive health, because these chemicals may affect reproductive tissues directly or indirectly through endocrine disruption. Given the declining global trends of female reproductive capacity and the potential ability of phthalates and their alternatives to negatively impact female reproductive health, a more comprehensive study is needed to understand their effects on the human body and their underlying mechanisms. These findings may have an important role in improving female reproductive health and in turn decreasing the number of complications during pregnancy.

Perfluorooctane sulfonic acid modulates expression of placental steroidogenesis-associated genes and hormone levels in pregnant rats

Perfluorooctane sulfonate (PFOS) is a widespread and persistent chemical in the environment. Reports show that PFOS is a potential endocrine disruptor; however, the possible effects of PFOS on placental endocrine function are unclear. This study aimed to investigate the endocrine-disrupting effects of PFOS on the placenta in pregnant rats and its potential mechanism. Pregnant rats from gestational days 4–20 were exposed to 0, 10, and 50 μg/mL PFOS through drinking water followed by analysis of various biochemical parameters. PFOS dose-dependently decreased fetal and placental weight in both sexes, with a specific decrease in weight of labyrinth but not junctional layer. Plasma progesterone (↑166%), aldosterone (↑201%), corticosterone (↑205%), testosterone (↑45%), luteinizing hormone (↑49%) levels were significantly increased, while estradiol (↓27%), prolactin (↓28%) and hCG (↓62%) levels were reduced in groups exposed to higher doses of PFOS. Real-time quantitative reverse transcriptase-polymerase chain reaction analysis revealed a significant increase in mRNA levels of placental steroid biosynthesis enzymes, including Cyp11A1 and 3β-HSD1 in male placenta and StAR, Cyp11A1, 17β-HSD1 and 17β-HSD3 in female placenta of PFOS dams. Cyp19A1 expression in ovaries was significantly decreased in PFOS dams. mRNA levels for placental steroid metabolism enzyme UGT1A1 increased in male but not in female placenta of PFOS dams. These results suggest that the placenta is a target tissue of PFOS and PFOS-induced dysregulation in steroid hormone production might be related to the altered expression of hormone biosynthesis and metabolism enzyme genes in the placenta. This hormone disruption might affect maternal health and fetal growth.

Are sugar substitutes potential endocrine disruptors?

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Vitamin D receptor antagonist activity in wastewater effluents—potential for endocrine disruption

BackgroundEndocrine disrupting chemicals have been identified for a number of human endocrine systems, but there are no reports on vitamin D-antagonistic activities in environmental samples.ObjectivesWe have investigated if there are compounds present in the environment that can act as Vitamin D receptor (VDR) antagonists.MethodsWater samples were collected of the influent and effluent water from five Swedish wastewater treatment facilities and concentrated with solid phase extraction. VDR antagonistic properties of the samples were tested with a cell-based in vitro assay responsive to vitamin D signaling. Cytotoxicity was monitored by three different assays.ResultsWe observed a dose-dependent decrease in the VDR signaling in most studied samples, although the effect was overlapping with cytotoxicity for the influent samples. For effluent samples, we observed clear VDR antagonistic effects also in non-cytotoxic concentrations. The observed effects could not be explained by presence of natural organic matter or cadmium in the water.DiscussionThe vitamin D endocrine system regulates a broad range of physiological processes, and disruption of this system could be associated with serious health consequences. In this study, we report environmental presence of compounds with VDR antagonistic properties, compounds which constitute a new group of potential endocrine disruptors. The VDR antagonism was observed in wastewater treatment facility effluent waters, which are discharged into water systems used as raw water for drinking water production. The findings reported in this study may indicate a potential hazard to human health and aquatic life. Future research is needed to investigate the presence of VDR antagonists in the environment, identification of the causative compounds, and studies of exposure of humans and aquatic organisms to these compounds.

Safety assessment of organic micropollutants in reclaimed water: Chemical analyses, ecological risk assessments, and in vivo endocrine-disrupting studies

Reclaimed water from municipal wastewater has great potential in mitigating the water resource crisis, while the inevitable residue of organic micropollutants (OMPs) challenges the safety of reclaimed water reuse. Limited information was available regarding the overall adverse effects of mixed OMPs in reclaimed water, especially the endocrine-disrupting effects on living organisms. Herein, chemical monitoring in two municipal wastewater treatment plants showed that 31 of 32 candidate OMPs including polycyclic aromatic hydrocarbons (PAHs), phenols, pharmaceuticals and personal care products (PPCPs) were detected in reclaimed water, with a concentration ranging from ng/L to μg/L. Then, based on the risk quotient value, phenol, bisphenol A, tetracycline, and carbamazepine were ranked as high ecological risks. Most PAHs and PPCPs were quantified as medium and low risks, respectively. More importantly, using aquatic vertebrate zebrafish as an in vivo model, the endocrine-disrupting potentials of OMP mixtures were comprehensively characterized. We found that a realistic exposure to reclaimed water induced estrogen-like endocrine disruption and hyperthyroidism in zebrafish, abnormal expression of genes along the hypothalamus-pituitary-thyroid (-gonad) axes, reproductive impairment, and transgenerational toxicity. Based on the chemical analyses, risk quotient calculations, and biotoxicity characterization, this study contributed to understanding the ecological risks of reclaimed water and developing the control standards for OMPs. In addition, application of the zebrafish model in this study also highlighted the significance of in vivo biotoxicity test in water quality evaluation.

Urinary Paraben Derivatives in Infertile Women; Is It a Cause of Concern?

Background: Parabens (PBs) may have potential endocrine disruption effects and may affect fertility. Objectives: This study aimed to find the relationship between the urinary concentration of PB derivatives, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), with the hormonal profile and in vitro fertilization (IVF) outcomes of infertile women. Methods: This case-control study was conducted in an academic center in Tehran from April to December 2021. The demographic data and lifestyle components as well as the urinary MP, EP, PP, and BP among the infertile and fertile women were evaluated and compared. Also, in infertile patients, the correlation between the hormonal profile and IVF outcomes (the number and quality of oocytes and embryos) with urinary PBs was assessed and reported. Results: A total of 206 women were included in the study. The distribution of urinary PB concentrations between groups was not significantly different. The frequency and comparison of used personal care products, cosmetics, detergents, and foodstuffs for some items except folic acid were significantly higher in the control group. Comparing the effects of PBs on hormones, a significant impact of MP on estradiol was observed for the second, third, and fourth quantiles. The follicle-stimulating hormone was significantly affected by the fourth quartile of EP. Additionally, the effect of EP on anti-mullerian hormones was negative and significant for the fourth quartile compared to the first quartile. Conclusions: Urinary PB levels may not be an indicator for infertility and hormonal distribution, at least for a short duration, and did not impact IVF outcomes.

Dietary intake of polychlorinated dibenzo-p-dioxins and furans, adiposity and obesity status.

IntroductionThe principal source of exposure to Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) in humans comes from food intake. PCDD/Fs, are a family of potential endocrine disruptors and have been associated with different chronic diseases such as diabetes and hypertension. However, studies assessing the relationship between dietary exposure to PCDD/Fs and adiposity or obesity status in a middle-aged population are limited. ObjectiveTo assess cross-sectionally and longitudinally the associations between estimated dietary intake (DI) of PCDD/Fs and body mass index (BMI), waist circumference, and the prevalence/incidence of obesity and abdominal obesity in a middle-aged population. MethodsIn 5899 participants aged 55–75 years (48% women) living with overweight/obesity from the PREDIMED-plus cohort, PCDD/Fs DI was estimated using a 143-item validated food-frequency questionnaire, and the levels of food PCDD/F expressed as Toxic Equivalents (TEQ). Consequently, cross-sectional and prospective associations between baseline PCDD/Fs DI (in pgTEQ/week) and adiposity or obesity status were assessed at baseline and after 1-year follow-up using multivariable cox, logistic or linear regression models. ResultsCompared to participants in the first PCDD/F DI tertile, those in the highest tertile presented a higher BMI (β-coefficient [confidence interval]) (0.43kg/m2 [0.22; 0.64]; P-trend <0.001), a higher waist circumference (1.11 cm [0.55; 1.66]; P-trend <0.001), and a higher prevalence of obesity and abdominal obesity (1.05 [1.01; 1.09] and 1.02 [1.00; 1.03]; P-trend = 0.09 and 0.027, respectively). In the prospective analysis, participants in the top PCDD/F DI baseline tertile showed an increase in waist circumference compared with those in the first tertile after 1-year of follow-up (β-coefficient 0.37 cm [0.06; 0.70]; P-trend = 0.015). ConclusionHigher DI of PCDD/Fs was positively associated with adiposity parameters and obesity status at baseline and with changes in waist circumference after 1-year of follow-up in subjects living with overweight/obesity. Further large prospective studies using a different population with longer follow-up periods are warranted in the future to strengthen our results.

Genotoxicity and endocrine disruption potential of haloacetic acids in human placental and lung cells

Chlorination of water results in the formation of haloacetic acids (HAAs) as major disinfection byproducts (DBPs). Previous studies have reported some HAAs species to act as cytotoxic, genotoxic, and carcinogenic. This work aimed at further exploring the toxicity potential of the most investigated HAAs (chloroacetic (CAA), bromoacetic (BAA), iodoacetic (IAA) acid) and HAAs species with high content of bromine (tribromoacetic acid (TBAA)), and iodine in their structures (chloroiodoacetic (CIAA) and diiodoacetic acid (DIAA)) to human cells. Novel knowledge was generated regarding cytotoxicity, oxidative stress, endocrine disrupting potential, and genotoxicity of these HAAs by using human placental and lung cells as in vitro models, not previously used for DBP assessment. IAA showed the highest cytotoxicity (EC50: 7.5 μM) and ability to generate ROS (up to 3-fold) in placental cells, followed by BAA (EC50: 20–25 μM and 2.1-fold). TBAA, CAA, DIAA, and CIAA showed no significant cytotoxicity (EC50 > 250 μM). All tested HAAs decreased the expression of the steroidogenic gene hsd17b1 up to 40 % in placental cells, and IAA and BAA (0.01–1 μM) slightly inhibited the aromatase activity. HAAs also induced the formation of micronuclei in A549 lung cells after 48 h of exposure. IAA and BAA showed a non-significant increase in micronuclei formation at low concentrations (1 μM), while BAA, CAA, CIAA and TBAA were genotoxic at exposure concentrations above 10 μM (100 μM in the case of DIAA). These results point to genotoxic and endocrine disruption effects associated with HAA exposure at low concentrations (0.01–1 μM), and the usefulness of the selected bioassays to provide fast and sensitive responses to HAA exposure, particularly in terms of genotoxicity and endocrine disruption effects. Further studies are needed to define thresholds that better protect public health.

Estetrol has a lower impact than 17α-ethinylestradiol on the reproductive capacity of zebrafish (Danio rerio)

Natural and synthetic oestrogens are commonly found in aquatic ecosystems. The synthetic oestrogen 17α-ethinylestradiol (EE2) is widely used in oral contraceptives and its ecotoxicological effects on aquatic organisms have been widely reported. The natural oestrogen estetrol (E4) was recently approved for use in a new combined oral contraceptive and, after therapeutic use, is likely to be found in the aquatic environment. However, its potential effects on non-target species such as fish is unknown. In order to characterize and compare the endocrine disruptive potential of E4 with EE2, zebrafish (Danio rerio) were exposed to E4 or EE2 in a fish short-term reproduction assay conducted according to OECD Test Guideline 229. Sexually mature male and female fish were exposed to a range of concentrations, including environmentally relevant concentrations of E4 and EE2, for 21 days. Endpoints included fecundity, fertilization success, gonad histopathology, head/tail vitellogenin concentrations, as well as transcriptional analysis of genes related to ovarian sex steroid hormones synthesis. Our data confirmed the strong impact of EE2 on several parameters including an inhibition of fecundity, an induction of vitellogenin both in male and female fish, an alteration of gonadal structures and the modulation of genes involved in sex steroid hormone synthesis in female fish. In contrast, only few significant effects were observed with E4 with no impact on fecundity. The results suggest that the natural oestrogen, E4, presents a more favorable environmental profile than EE2 and is less likely to affect fish reproductive capacity.

Levonorgestrel causes feminization and dose-dependent masculinization in medaka fish (Oryzias latipes): Endocrine-disruption activity and its correlation with sex reversal

The effect of a synthetic progestin, levonorgestrel (LNG), on the sex of exposed embryos was examined in medaka fish (Oryzias latipes). The aims of this study are to clarify the dual effect of LNG on sex and the correlation with its androgenic/estrogenic potential in medaka. LNG exposure causes significant dose-dependent masculinization (0.1–100 μg/L), whereas a decrease in the masculinization ratio is observed at 100 μg/L. LNG also causes significant feminization at 1–100 μg/L, but not in a dose-dependent manner. Exposure of estrogen-responsive gene (choriogeninH-EGFP) transgenic embryos to 100 μg/L LNG produced significant fluorescent signals in hatched fry. In vitro transcriptional assays indicated that LNG at 10−7–10−5 M induced significant activity for estrogen receptor (ESR)2a and ESR2b, but not for ESR1. In pre-self-feeding fry at 5 days post hatching (dph), 1–100 μg/L LNG caused a significant increase in the mRNA of choriogeninH, irrespective of genetic sex. Moreover, LNG (10−10–10−5 M) also caused a significant increase in the transcriptional activity of androgen receptor (AR) α and ARβ in vitro, and 0.1 μg/L LNG significantly increased the mRNA levels of a testis-differentiation initiation factor, gonadal soma-derived factor (gsdf), as an androgen-upregulated and estrogen-downregulated gene, in 5 dph XX fry to levels similar to those in the control XY fry. However, 100 and 10 μg/L LNG suppressed or did not induce gsdf mRNA expression in XY and XX fry, respectively. Together, these findings show that LNG exerts estrogenic and androgenic activities in different concentration ranges, which correlate with the ratio of LNG-induced sex reversal. These results suggest for the first time, that medaka exposure to LNG can induce masculinization and feminization, based on the balance between androgenic and estrogenic activities, and the protocol applied in this study represents an alternative to the traditional animal model used to screen for endocrine-disrupting potential.

Chlorpropham, a carbamate ester herbicide, has an endocrine-disrupting potential by inhibiting the homodimerization of human androgen receptor

This study was carried out to provide the evidence with respect to the adverse potential of chlorpropham, a representative carbamate ester herbicide product, on the endocrine system by using in vitro testing methods in accordance with the Organization for Economic Cooperation and Development Test Guideline No. 458 (22Rv1/MMTV_GR-KO human androgen receptor [AR] transcriptional activation assay) and a bioluminescence resonance energy transfer-based AR homodimerization assay. Results revealed that chlorpropham had no AR agonistic effects, but it was determined to be a true AR antagonist without intrinsic toxicity against the applied cell lines. In the mechanism of chlorpropham-induced AR-mediated adverse effects, chlorpropham suppressed cytoplasmic AR translocation to the nucleus by inhibiting the homodimerization of the activated ARs. This suggests that chlorpropham exposure caused endocrine-disrupting effects through its interactions with human AR. Additionally, this study might help identify the genomic pathway of the AR-mediated endocrine-disrupting potential of N-phenyl carbamate herbicides.

Exposure, toxicological mechanism of endocrine disrupting compounds and future direction of identification using nano-architectonics

Endocrine-disrupting compounds (EDC) are a group of exogenous chemicals that structurally mimic hormones and interfere with the hormonal signaling cascade. EDC interacts with hormone receptors, transcriptional activators, and co-activators, altering the signaling pathway at both genomic and non-genomic levels. Consequently, these compounds are responsible for adverse health ailments such as cancer, reproductive issues, obesity, and cardiovascular and neurological disorders. The persistent nature and increasing incidence of environmental contamination from anthropogenic and industrial effluents have become a global concern, resulting in a movement in both developed and developing countries to identify and estimate the degree of exposure to EDC. The U.S. Environment Protection Agency (EPA) has outlined a series of in vitro and in vivo assays to screen potential endocrine disruptors. However, the multidisciplinary nature and concerns over the widespread application demand alternative and practical techniques for identifying and estimating EDC. The review chronicles the state-of-art 20 years (1990–2023) of scientific literature regarding EDC's exposure and molecular mechanism, highlighting the toxicological effects on the biological system. Alteration in signaling mechanisms by representative endocrine disruptors such as bisphenol A (BPA), diethylstilbestrol (DES), and genistein has been emphasized. We further discuss the currently available assays and techniques for in vitro detection and propose the prominence of designing nano-architectonic-sensor substrates for on-site detection of EDC in the contaminated aqueous environment.

In silico profiling of endocrine-disrupting potential of bisphenol analogues and their halogenated transformation products.

Due to its endocrine-disrupting properties, bisphenol A (BPA) is being phased out from plastics, thermal paper and epoxy resins, and its replacements are being introduced into the market. Bisphenols are released into the environment, where they can undergo halogenation. Unlike BPA, the endocrine-disrupting potential of BPA analogues and their halogenated transformation products has not been extensively studied. The aim of this study was to evaluate the endocrine-disrupting potential of 18 BPA analogues and their halogenated derivatives by calculating affinities for 14 human nuclear receptors utilizing the Endocrine Disruptome and VirtualToxLab™ in silico tools. Our simulations identified AR, ERs, and GR as the most favorable targets of bisphenols and their derivatives. Several BPA analogues displayed a higher predicted potential for endocrine disruption than BPA. Our models highlighted BPZ and BPPH as the most hazardous in terms of predicted endocrine activities. Halogenation, in general, was predicted to increase the binding affinity of bisphenols for AR, ERβ, MR, GR, PPARγ, and TRβ. Notably, mono- or 2,2'-di-halogenated bisphenols exhibited the highest potential for endocrine disruption. In vitro corroboration of the obtained results should be the next milestone in evaluating the safety of BPA substitutes and their halogenated transformation products.

Presence of methyl paraben in anti-diabetic herbal preparations

Plant-based hypoglycemic therapeutics have been increasing in consumption due to the escalation of type 2 diabetes and its related complications. However, the safety of the preparations is little understood. Parabens (alkyl esters of p-hydroxybenzoic acid) are widely used as preservatives in these pharmaceuticals. However, the presence of methylparaben in formulations raises anxiety due to its potential endocrine disruption functions. Endocrine disruption could lead to undesirable health abnormalities and carcinogenic, estrogenic, and adverse reproductive effects. The present investigation directs toward estimating of methylparaben in some anti-diabetic herbal preparations using UV- Vis spectrophotometric method abiding by International Conference on Harmonization (ICH) guidelines for validation. The analytical wavelength of methylparaben in methanol was determined and found at 256.5 nm. The method obeys Beer’s law in the analytical range and has a good coefficient of determination (r2= 0.9881). The limit of detection (LOD) and limit of quantification (LOQ) were 0.19 ppm and 0.57 ppm, respectively. Recoveries were 91.3-98.8% in analyte-free plant matrix and 91-105.8 % in a diluent. The coefficient of variation (CV%) varied between 0.005- 0.268% for different standards. Results of forty-eight anti-diabetic herbal preparations showed methylparaben was detected in thirty-four samples in the range of 13.12 – 325.13 mg/day with a mean exposure value of 78.25 mg/day. However, none of the samples raise concerns about safety (the safety ceiling for paraben is 420 mg/day). More investigation is required to determine, whether the herbal drugs are safe to consume in terms of methylparaben. J. Asiat. Soc. Bangladesh, Sci. 48(1-2): 41-52, June-December 2022

Estrogenic Potencies of Phytoestrogens Commonly Found in Soybean (Glycine Max) Assessed by use of MMV-Luc Cell Line Bioassay

Purpose: Phytoestrogens (PE) are weakly estrogenic compounds synthesized in plants, especially in climatic adversity. The endocrine disruptive activity of PEs and some of their human metabolites are of concern as they have been associated with positive and more so negative health effects.&#x0D; Methodology: The transcriptional activities (TAs) of ten PEs (apigenin, daidzein, daidzin, equol, enterodiol, formononetin, genistein, genistin, glycitein, and matairesinol) were measured as induction of the expressed luciferase activity which is correlates with biological effects. These effects were compared to transcription caused by 17β-estradiol (5 nM) hormone (standards) in vitro. This was done by the use of estrogenic receptors in the MMV-Luc cell line using a reporter gene assay tool. &#x0D; Findings: Standard curves for hormone standards were determined and the EC50 for 17β-estradiol was (4.5 x 10-11M). The order of PEs potency for the ER (ERα and ERβ) in the MMV-Luc cell line, as determined from the EC50s (M) of their dose-response curves were in the following order: equol (4.9 x 10-7M) &gt; formononetin (5.7 x 10-6M) &gt; apigenin(2.4 x 10-6M) &gt; genistein (2.1 x 10-6M ) &gt; daidzein(3.3 x 10-5M). Standard curves for the rest were not achieved in the MMV-Luc cell line at the tested concentrations. The % estrogenic potencies of these compounds varied from 9 x 10-3M for equol to 1.4 x 10-4M for daidzein, relative to 17β-estradiol whose percent potency was arbitrarily assigned a value of 100. This study successfully characterized the TA of ten PEs in MMV-Luc cell lines. By achieving and exceeding a full estrogenic effect in MMV-Luc cells, it was indicative that the phytoestrogen transcriptive activity was most likely through non-receptor mechanisms such as enzymatic pathways.&#x0D; Recommendations: Although the potential for endocrine disruption by PE was noted in vitro, this study would recommend further in vivo tests. This is because toxicokinetics involving metabolism and bioavailability affects the potencies of the PEs. Further in vitro assays may be designed to investigate the additive effects of phytoestrogens at physiologically relevant concentrations.

Potency of Hexaconazole to Disrupt Endocrine Function with Sex Hormone-Binding Globulin.

Hexaconazole is widely used as a fungicide for agricultural purposes. However, the endocrine-disrupting potential of hexaconazole is still under investigation. In addition, an experimental study found that hexaconazole may disrupt the normal synthesis of steroidal hormones. The potency of hexaconazole to bind with sex hormone-binding globulin (SHBG), a plasma carrier protein that binds androgens and oestrogens, is unknown. In this study, we evaluated the efficacy of hexaconazole to bind with SHBG by molecular interaction, a molecular dynamics method. In addition, principal component analysis was performed to understand the dynamical behaviour of hexaconazole with SHBG in comparison with dihydrotestosterone and aminoglutethimide. The binding scores of hexaconazole, dihydrotestosterone, and aminoglutethimide with SHBG were found to be -7.12 kcal/mol, -11.41 kcal/mol, and -6.84 kcal/mol, respectively. With respect to stable molecular interaction, hexaconazole showed similar molecular dynamics patterns of root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration (Rg), and hydrogen bonding. The solvent surface area (SASA) and principal component analysis (PCA) of hexaconazole exhibit similar patterns in comparison with dihydrotestosterone and aminoglutethimide. These results show that hexaconazole has a stable molecular interaction with SHBG, which may acquire the active site of the native ligand, resulting in significant endocrine disruption during agricultural work.

Visible-light induced photocatalytic degradation of estrone (E1) with hexagonal copper selenide nanoflakes in water

Steroid hormones, being potent endocrine-disruptors, are a menace to human health and aquatic life. Herein, visible-light induced photocatalytic degradation of estrone (E1) by hexagonal copper selenide (CuSe) nanoflakes has been reported. CuSe was synthesised by a facile and low-temperature (100 oC) co-precipitation method and was characterised. The nanocrystals were of stoichiometric Cu:Se ratio with Se2- and Cu in the + 1/+ 2 mixed-valence state and exhibited laminar, flake-like morphology with a preferred hexagonal close-packed structure (P63/mmc) having average particle size and thickness of 0.229 ± 0.146 µm and 0.05 ± 0.02 µm, respectively. The adsorption isotherms of E1 were linear and the adsorption process was exothermic. The reactivity of E1 under aqueous suspensions of CuSe exposed to visible light exhibited pseudo-first-order kinetics with a rate constant, k, that varied with initial E1 concentration, light power, catalyst dose, and pH. Particularly, k was almost constant over the range pH5–9 but substantially increased as pH rose to 11, while light power and catalyst dose increased k up to a maximum, and the initial concentration reduced k. Surprisingly, CuSe oxidised E1, even in the absence of light, and leached species that were identified and their time-dependency was determined. We concluded that the disappearance of E1 by CuSe is attributed to synergetic effects of adsorption, oxidation by CuSe, and photocatalytic degradation. Supported by liquid-mass spectrometry analysis and molecular chemistry calculations, we also suggested a possible mechanism for E1 degradation. Thus, hexagonal CuSe nanocrystals can be a promising candidate for the treatment of endocrine-disrupting chemicals (EDC)-contaminated wastewaters.

Pharmacological intervention of biosynthesized Nigella sativa silver nanoparticles against hexavalent chromium induced toxicity in male albino mice

Hexavalent chromium, toxic heavy metal, among the top-rated environmental contaminants, is declared a potent endocrine disruptor in humans and animals. The present study was planned to find harmful effects on the reproductive system caused by Cr (VI) and the ameliorative effect of Nigella sativa and Nigella sativa-mediated AgNP on male mice (Mus musculus). In the present study, known infertility medicine, clomiphene citrate is also used as a positive control. The main objective of the present study was to assess the ameliorative potential of oral administration of a dose of 50 mg/kg BW clomiphene citrate (control), AgNP via chemical synthesis, Nigella sativa seed extract, and Nigella sativa-mediated AgNP against the Cr (VI) at the dose of 1.5 mg/kg BW from K2Cr2O7 orally induced toxicity over eight weeks on the reproductive performance of male albino mice. Nigella sativa mediated AgNPs were characterized by UV, SEM, FTIR, and XRD. The histological analysis, smear study, antioxidant capacity test, and hormone analysis were conducted by blood samples of albino mice. Cr exposed groups showed a significant decrease in sperm head breadth (5.29 ± 0.54 µ) and length (19.54 ± 1.18 µ), middle piece length, tail length, LH (1.65 ± 0.15 ng/mL), testosterone (2.63 ± 0.29 ng/mL), SOD (61.40 ± 2.48 mmol/mL), CAT (87.40 ± 6.01 mmol/mL), GSH (1.54 ± 0.09 µmol/mL), and no of spermatogonia (1.22 ± 0.25), and spermatocytes (2.33 ± 0.943). However, FSH level (160.00 ± 4.98 ng/mL), seminiferous tubule CSA (1094.69 ± 49.76 mm2), size of spermatogonia (41.30 ± 1.24 µ), and spermatocytes (26.07 ± 1.34 µ) were significantly increased. Administration of Nigella sativa and Nigella sativa-mediated AgNPs reduced the toxicity.

Contribution of Reliable Chromatographic Data in QSAR for Modelling Bisphenol Transport across the Human Placenta Barrier.

Regulatory measures and public concerns regarding bisphenol A (BPA) have led to its replacement by structural analogues, such as BPAF, BPAP, BPB, BPF, BPP, BPS, and BPZ. However, these alternatives are under surveillance for potential endocrine disruption, particularly during the critical period of fetal development. Despite their structural analogies, these BPs differ greatly in their placental transport efficiency. For predicting the fetal exposure of this important class of emerging contaminants, quantitative structure-activity relationship (QSAR) studies were developed to model and predict the placental clearance indices (CI). The most usual input parameters were molecular descriptors obtained by modelling, but for bisphenols (BPs) with structural similarities or heteroatoms such as sulfur, these descriptors do not contrast greatly. This study evaluated and compared the capacity of QSAR models based either on molecular or chromatographic descriptors or a combination of both to predict the placental passage of BPs. These chromatographic descriptors include both the retention mechanism and the peak shape on columns that reflect specific molecular interactions between solute and stationary and mobile phases and are characteristic of the molecular structure of BPs. The chromatographic peak shape such as the asymmetry and tailing factors had more influence on predicting the placental passage than the usual retention parameters. Furthermore, the QSAR model, having the best prediction capacity, was obtained with the chromatographic descriptors alone and met the criteria of internal and cross validation. These QSAR models are crucial for predicting the fetal exposure of this important class of emerging contaminants.

Using the grey literature to better understand the potential health impacts of cabin air quality

This paper presents an extensive database of 450 chemicals reported in the grey literature (technical reports and documents) in association with the aircraft cabin environment. 72% (325 chemicals) of these exhibited toxic properties. The most affected target organs were skin (302 chemicals), eyes (294 chemicals), respiratory system (234 chemicals), and central nervous system (94 chemicals). The database includes available occupational exposure limits for a wide range of these pollutants (118). Results from technical reports on pollutant levels in aircraft were compared against their threshold health-based screening values. When performing a human health risk assessment on a chemical-by-chemical basis, there were no exceedances of average concentrations against workplace exposure limits. However, there were exceedances in maximum reported concentrations for ozone and acrolein. When chemical exposure was assessed additively for chemicals affecting the same target organs, the average concentrations did not exceed workplace limits. However, there were exceedances for maximum concentrations for compounds that targeted the eyes, skin, cardiovascular system, blood, and respiratory system. When performing a conservative additive risk assessment of endocrine disruptors (and potential endocrine disruptors), exceedances were observed when compared with no observed adverse effect levels (NOAEL) and workplace exposure thresholds established for confirmed endocrine disruption. Our results indicate that no single chemical is responsible for the adverse health effects reported by aircrew and instead point towards a combination of chemicals and additional factors. This work stresses the need for more comprehensive assessments that are coupled with epidemiological studies and risk assessments that consider exposure to multiple pollutants and specificities of the environment inside aircraft.