Urinary levels, composition profile and cumulative risk of bisphenols in preschool-aged children from Nanjing suburb, China

Bisphenol-F and Bisphenol-S (BPF and BPS) Impair the Stemness of Neural Stem Cells and Neuronal Fate Decision in the Hippocampus Leading to Cognitive Dysfunctions

Neurogenesis occurs throughout life in the hippocampus of the brain, and many environmental toxicants inhibit neural stem cell (NSC) function and neuronal generation. Bisphenol-A (BPA), an endocrine disrupter used for surface coating of plastic products causes injury in the developing and adult brain; thus, many countries have banned its usage in plastic consumer products. BPA analogs/alternatives such as bisphenol-F (BPF) and bisphenol-S (BPS) may also cause neurotoxicity; however, their effects on neurogenesis are still not known. We studied the effects of BPF and BPS exposure from gestational day 6 to postnatal day 21 on neurogenesis. We found that exposure to non-cytotoxic concentrations of BPF and BPS significantly decreased the number/size of neurospheres, BrdU+ (proliferating NSC marker) and MAP-2+ (neuronal marker) cells and GFAP+ astrocytes in the hippocampus NSC culture, suggesting reduced NSC stemness and self-renewal and neuronal differentiation and increased gliogenesis. These analogs also reduced the number of BrdU/Sox-2+, BrdU/Dcx+, and BrdU/NeuN+ co-labeled cells in the hippocampus of the rat brain, suggesting decreased NSC proliferation and impaired maturation of newborn neurons. BPF and BPS treatment increases BrdU/cleaved caspase-3+ cells and Bax-2 and cleaved caspase protein levels, leading to increased apoptosis in hippocampal NSCs. Transmission electron microscopy studies suggest that BPF and BPS also caused degeneration of neuronal myelin sheath, altered mitochondrial morphology, and reduced number of synapses in the hippocampus leading to altered cognitive functions. These results suggest that BPF and BPS exposure decreased the NSC pool, inhibited neurogenesis, induced apoptosis of NSCs, caused myelin degeneration/synapse degeneration, and impaired learning and memory in rats.

Assessment of potential environmental and human risks for Bisphenol AF contaminant

Bisphenol AF (BPAF) is found in high concentrations in aquatic environments due to the increased use of thermal paper and food packaging. However, there have been relatively few toxicological studies and potential risk assessments of BPAF. In this study, the risk quotient (RQ) and hazard quotient (HQ) of BPAF were derived to present the safety standards for environmental risk management and protection in lakes, rivers, bays, and Italian regions. We applied the species sensitivity distribution (SSD) method based on the previous ecotoxicological data and the results of supplementary toxicity tests on BPAF. From the SSD curves, the hazardous concentration for 5 % of the species (HC5) values for the acute and chronic toxicity data were 464.75 µg/L and 3.59 µg/L, respectively, and the acute- and chronic-based predicted no-effect concentration were derived as 154.92 µg/L and 1.20 µg/L, respectively. The acute-based RQ (RQA)values of BPAF in all regions were negligible (RQ < 0.1). The chronic-based RQ (RQC) in the Xitang River (XR) and the Central Italy (CI) showed a considerably high ecological risk (12.77 and 1.29) and the Hangzhou Bay (0.21), the South and North Italy (0.79 and 0.27), and the Tamagawa River (0.13) had a medium ecological risk (0.1 < RQ < 1.0). However, the HQ values based on the tolerable daily intake for BPAF over all age groups in these regions was < 0.1, indicating the low health risk. Nonetheless, the result of this study indicates that BPAF contamination is serious in XR and CI, and their use and emissions require continuous monitoring.

Exposure characteristics and cumulative risk assessment of bisphenol A and its substitutes: the Taiwan environmental survey for toxicants 2013

Introduction

Ever since the use of bisphenol A (BPA) has been restricted, concerns have been raised regarding the use of its substitutes, such as bisphenol S (BPS) and bisphenol F (BPF). Meanwhile, the EU European Food Safety Authority (EFSA) issued the new tolerable daily intake (TDI) after the latest re-risk assessment for BPA, which enforced the need for cumulative risk assessment in the population. This study was conducted to identify BPA and its substitute's exposure characteristics of the general Taiwanese population and estimate the cumulative risk of bisphenol exposure.

Methods

Urine samples (N = 366 [adult, 271; minor, 95]) were collected from individuals who participated in the Taiwan Environmental Survey for Toxicants 2013. The samples were analyzed for BPA, BPS, and BPF through ultraperformance liquid chromatography-tandem mass spectrometry. Daily intake (DI) levels were calculated for each bisphenol. Hazard quotients (HQs) were calculated with the consideration of tolerable DI and a reference dose. Additionally, hazard index (HI; sum of HQs for each bisphenol) values were calculated.

Results

Our study found that the median level of BPA was significantly higher in adults (9.63 μg/g creatinine) than in minors (6.63 μg/g creatinine) (p < 0.001). The DI of BPS was higher in female (0.69 ng/kg/day) than in male (0.49 ng/kg/day); however, the DIs of BPF and BPS were higher in boys (1.15 and 0.26 ng/kg/day, respectively) than in girls (0.57 and 0.20 ng/kg/day, respectively). Most HI values exceeded 1 (99% of the participants) after EFSA re-establish the TDI of BPA.

Discussion

Our study revealed that the exposure profiles and risk of BPA and its substitute in Taiwanese varied by age and sex. Additionally, the exposure risk of BPA was deemed unacceptable in Taiwan according to new EFSA regulations, and food contamination could be the possible source of exposure. We suggest that the risk of exposure to BPA and its substitutes in most human biomonitoring studies should be reassessed based on new scientific evidence.

Neurodevelopmental toxicity of bisphenol AF in zebrafish larvae and the protective effects of curcumin

Bisphenol AF (BPAF) is one of the most commonly used alternatives of bisphenol A in the plastics industry. The effects of BPAF on nervous development are unclear. Curcumin (CUR) has been determined to be an anti-inflammatory and antioxidant agent. In this study, the effects of BPAF on neurotoxicity of zebrafish embryos/larvae and whether CUR could reverse effects induced by BPAF were investigated. The results showed that BPAF treatment induced deficits in locomotor behavior, altered the larval brain development, caused aberrant expression of neurogenesis related genes (elavl3, zn5, α-tubulin, syn2a, and gap43), decreased acetylcholinesterase (AChE) activity, and induced oxidative stress, cell apoptosis, and neuroinflammation in zebrafish larvae. CUR addition could block the adverse effects of BPAF on nervous development by attenuated oxidative stress and cell apoptosis induced by BPAF in zebrafish, enhanced the activity of AChE, and increased the expression of genes involved in the pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, and IL-8). The results of this study indicate that BPAF could induce aberrant development on nervous system. However, CUR exerts neuroprotective effects on BPAF-induced neurotoxicity in zebrafish larvae.

Curcumin alleviates bisphenol AF-induced oxidative stress and apoptosis in caprine endometrial epithelial cells via the Nrf2 signaling pathway

Bisphenol AF (BPAF), a BPA-substitute, has been widely used in industrial compounds throughout the world. Several studies have shown that BPAF has endocrine interference and reproductive toxicity. However, the toxic effects of BPAF on pregnancy and placenta of goats are still unclear. Therefore, the objective of this study was to reveal the toxic effect of BPAF by using an in vitro culture model of caprine endometrial epithelial cells (EECs) and further attempted to alleviate the toxicity by curcumin pretreatment. The results showed that BPAF induces significant effects on EECs, including decreased cell viability and mitochondrial membrane potential (△ψm), elevating intracellular reactive oxygen species (ROS), promoting cell apoptosis through upregulating the expression of Bax, Cytochrome c, and downregulating the expression of Bcl-2. Meanwhile, BPAF induced dysregulation of oxidative stress by increasing the levels of malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) but decreasing the activities of superoxide dismutase (SOD). However, curcumin pretreatment could significantly attenuate BPAF-induced toxic effects in EECs. Further study revealed that BPAF treatment could activate mitogen-activated protein kinase (MAPK) pathway and nuclear factor-erythroid 2-related factor 2 (Nrf2) expression, but curcumin pretreatment significantly inhibited the activation of MAPK signal pathway and Nrf2 expression induced by BPAF. Overall, this study indicated that curcumin could prevent BPAF-induced EECs cytotoxicity, which provides a potential therapeutic strategy for female infertility associated with BPAF exposure.

Associations of exposure to bisphenol A and its substitutes with neurodevelopmental outcomes among infants at 12 months of age: A cross-sectional study

BACKGROUND

Bisphenol A (BPA) exposure has been linked to adverse childhood neurodevelopment, but little is known about whether BPA substitutes exposures are also related to childhood neurodevelopment.

OBJECTIVES

To investigate the associations of exposure to BPA and its substitutes with infant neurodevelopment at 12 months.

METHODS

A total of 420 infants at 12 months were included from the Laizhou Wan (Bay) Birth Cohort in Shandong, China. Urinary concentrations of BPA and its substitutes including bisphenol S (BPS), bisphenol B (BPB), bisphenol AF (BPAF), bisphenol AP (BPAP), bisphenol P (BPP) and bisphenol Z (BPZ) were measured. Developmental quotient (DQ) scores based on the Gesell Development Schedules (GDS) were used to evaluate infant neurodevelopment. The multivariable linear regression and weighted quantile sum (WQS) regression were applied to estimate the associations of exposure to individual bisphenols and their mixtures with DQ scores, respectively. Sex-stratified analyses were also performed.

RESULTS

BPA was detected in most infants (89.05%) and had the highest median concentration (0.709 ng/mL) among all bisphenols. BPA substitutes except BPZ were ubiquitous in infants' urine samples (>70%), and BPS showed the highest median concentration (0.064 ng/mL) followed by BPAP (0.036 ng/mL), BPAF (0.028 ng/mL), BPP (0.015 ng/mL) and BPB (0.013 ng/mL). In multivariable linear regression, only BPAF exposure was inversely associated with social DQ scores among all infants (β = -0.334; 95% CI: -0.650, -0.019). After sex stratification, this inverse association was significant in girls (β = -0.605; 95% CI: -1.030, -0.180). Besides, BPA exposure was negatively related to gross motor DQ scores in boys (β = -1.061; 95% CI: -2.078, -0.045). WQS analyses confirmed these results.

CONCLUSIONS

Our study suggests that bisphenol exposure during infancy may be associated with poor infant neurodevelopment, and BPAF as a commonly used BPA substitute contributing the most to this adverse association deserves more attention.

Spatiotemporal distribution and ecological risk assessment of pharmaceuticals and personal care products (PPCPs) from Luoma Lake, an important node of the South-to-North Water Diversion Project

PPCPs (pharmaceuticals and personal care products) are widely found in the environment and can be a risk to human and ecosystem health. In this study, spatiotemporal distribution, critical risk source identification and potential risks of 14 PPCPs found in water collected from sampling points in Luoma Lake and its inflowing rivers in two seasons in 2019 and 2020 were investigated. The PPCPs concentrations ranged from 27.64 ng·L-1 to 613.08 ng·L-1 in December 2019, and from 16.67 ng·L-1 to 3287.41 ng·L-1 in April 2020. Ketoprofen (KPF) dominated the PPCPs with mean concentrations of 125.85 ng·L-1 and 640.26 ng·L-1, respectively. Analysis of sources showed that the pollution in Luoma Lake mostly originated from sewage treatment plant effluents, inflowing rivers and domestic wastewater. Among them, the inflowing rivers contributed the most (82.95%) to the concentration of total PPCPs. The results of ecological risk assessment showed that there was a moderate risk (0.1 < RQs < 1) from carbamazepine (CBZ) in December 2019 and a high risk (RQs > 1) from naproxen (NPX) in April 2020. The results of human risk assessment found that NPX posed a high risk to infant health, and we found that NPX was associated with 83 diseases according to Comparative Toxicogenomics Database. NPX was identified as a substance requiring major attention. The results provide an understanding of the concentrations and ecological risks of PPCPs in Luoma Lake. We believe the data will support environmental departments to develop management strategies and prevent PPCPs pollution.

Association of urinary bisphenols with thyroid function in the general population: a cross-sectional study of an industrial park in China

Bisphenols (BPs) are potential thyroid disruptors that are widely used in many consumer products, leading to their widespread exposure in the general population. Current cross-sectional and case-control studies have found associations between exposure to BPs and serum thyroid function, but the results were contradictory. The objectives of this study are to describe demographic characteristics, BP exposure levels, and thyroid function measurements in potentially exposed and control districts and to investigate the association of urinary BPs with thyroid function. Data were collected from a general population aged 3-79 years (N = 281) recruited by the Zhejiang Human Biomonitoring Program (ZJHBP). The concentrations of 10 kinds of BPs in urine and serum free triiodothyronine (FT3), total triiodothyronine (TT3), free thyroxine (FT4), total thyroxine (TT4), thyroid-stimulating hormone (TSH), thyroglobulin (Tg), thyroglobulin antibodies (TgAb), thyroid peroxidase antibodies (TPOAb), and thyrotropin receptor antibody (TRAb) in serum were measured. Multiple linear regression and weighted quantile sum (WQS) regression were used to estimate the relationship between single and mixed exposure of BPs and thyroid function. Bisphenol A (BPA), bisphenol S (BPS), and bisphenol P (BPP) were detected, respectively, in 82.73%, 94.24%, and 55.40% of the population in the exposed area and 81.69%, 61.27%, and 43.66% of the population in the control area. Among adult females, serum TT3 was negatively associated with urinary BPA (β = -0.033, 95% CI = -0.071, -0.008, P = 0.021). Among minor females, FT4 and Tg levels were negatively associated with the urinary BPA (β = -0.026, 95% CI = -0.051, -0.002, P = 0.032 for FT4; β = -0.129, 95% CI = -0.248, -0.009, P = 0.035 for Tg), and TPOAb was positively associated with urinary BPA (β = 0.104, 95% CI = 0.006, 0.203, P = 0.039). In WQS models, BPs mixture was positively associated with FT3 (βWQS = 0.022, 95% CI = 0.002, 0.042) and TT3 (βWQS = 0.033, 95% CI = 0.004, 0.062), and negatively associated with FT4 (βWQS = -0.024, 95% CI = -0.044, 0.004). We found widespread exposure to BPA, BPS, and BPP in the general population of Zhejiang province and found an association between BPA and thyroid hormones. This association is gender- and age-dependent and needs to be confirmed in further studies.

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

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

A multi-framework for bisphenols based on their high performance and environmental friendliness: Design, screening, and recommendations

Bisphenols (BPs) have gained significant attention due to their extensive use in the production of medical equipment, packaging materials, and everyday commodities. Urgent attention is required for assessing and identifying the risks associated with BP exposure to the environment and human health, as well as developing regulatory strategies. In this paper, 29 common BPs were selected as the research object, high-performance BP substitutes with environmental and human health friendliness characteristics were designed and screened. The above eight BP substitutes were considered as examples, and the first-level evaluation indicators of BPs and their substitutes were predicted using a random forest classification/regression model. Subsequently, the key indicators affecting the first-level evaluation indicators were ranked. The ranking results were environmental friendliness (64.30%) > human health risk (18.00%) > functionality (17.69%), indicating that environmental friendliness was the main influencing factor for the first-level evaluation indicators of BPs and their substitutes. Therefore, the study employed density functional theory (DFT) to simulate the biodegradation pathways of BPs and their substitutes in contaminated soil and landfill leachate, using Derivative-50 as an example. Furthermore, the environmental risk associated with the degradation products was evaluated, and regulatory recommendations based on risk identification were proposed.

Occurrence of multiple bisphenol S analogues in children from Shantou, China

Emerging bisphenol S analogues (BPSs) have gained their application perspectives to replace bisphenol A (BPA) and BPA analogues (BPAs). However, the extent of human exposure and potential health risk from BPSs is rarely known yet. We hypothesized that children living in Shantou, China, a well-known e-waste recycling city, may expose to emerging BPSs together with BPA and BPAs. In this study, BPA, six commonly used BPAs and 11 emerging BPSs were determined simultaneously in 240 urine samples collected from children residing in Shantou. BPA, BPS, bisphenol F, bisphenol AF and three BPSs of 2,4'-bis(hydroxyphenyl)sulfone, 4-((4-(allyloxy)phenyl)sulfonyl)phenol and diphenylsulfone (DPS) were the urinary predominant bisphenols with detection frequencies of 67-100% in the children. BPA was found at the highest median concentration (3.36 µg/g creatinine) followed by BPS (0.313) and DPS (0.187). It is interesting to find that the girls and children in the younger group (2 ≤ age < 5) had consistently higher concentrations of the seven dominant bisphenols than the boys and these of the older group (5 ≤ age ≤ 10), respectively. The children with under/overweight suffered higher burdens of bisphenol exposure based on medians of estimated daily intakes. Association analysis results indicated that the Shantou children exposed themselves to multiple BPSs along with BPA and BPAs from assumed consumer products and/or contaminated environments.

Temporal trends in bisphenol exposures and associated health risk among Japanese women living in the Kyoto area from 1993 to 2016

BACKGROUND

Bisphenols, and especially bisphenol A, are widely used as components of epoxy resins and polycarbonate. Widespread detection and potential health risks have led to bisphenol A being replaced by other alternatives, including structurally similar bisphenol analogs. Several bisphenol analogs are suspected to have similar adverse health consequences. This study examined the temporal trends in bisphenol exposure among a group of Japanese women from 1993 to 2016, and assessed the associated health risks.

METHODS

We used archived single spot urine samples of healthy Japanese women living in the Kyoto area (n = 133) collected in 1993, 2000, 2003, 2009, 2011, and 2016. We measured the concentrations of 10 bisphenols in these samples.

RESULTS

A sharp increase in the detection rates of bisphenol F was observed after 2000. There was a distinct downward trend in urinary bisphenol A concentrations and an upward trend in bisphenol E concentrations after 2009. While the hazard index for all measured bisphenols was below 1 in all subjects, bisphenol F was determined as the most important risk driver after 2000, rather than bisphenol A.

DISCUSSION

Trends of decreasing bisphenol A and increasing bisphenol E exposure especially after 2011, along with no significant change in the sum of all bisphenol analogs in urine, provide clear evidence that bisphenol A has been replaced by other bisphenols in the study population. We found no significant change in the total exposure to bisphenols during the study period. Bisphenol F might become the most important bisphenol in terms of risk, while cumulative risks due to all bisphenol exposure were deemed insignificant. Considering the accumulating evidence indicating adverse effects at lower exposure levels, further studies are warranted to assess exposure and risk from bisphenol A analogs.

Temporal trends in risk of bisphenol A, benzophenone-3 and triclosan exposure among U.S. children and adolescents aged 6-19 years: Findings from the National Health and Nutrition Examination Survey 2005-2016

BACKGROUND

Phenolic compounds with potential adverse health effects are gradually being replaced. Little is known about the potential health risks of BPA, BP3, and TCS exposure in children and adolescents aged 6-19 years in the United States.

OBJECTIVES

To determine trends and rates of change in hazard indices (HI) for three phenolics in U.S. children and adolescents for BPA, BP3, TCS, and to assess changes in gender, race/ethnicity, age, and potential health risks.

METHODS

Metabolic biomonitoring data from field-collected urine samples from the National Health and Nutrition Examination Survey (NHANES) were utilized. Daily intake of three phenols (bisphenol A, benzophenone-3, and triclosan) between 2005 and 2016 in children and adolescents were obtained. Cumulative risk indicators, including hazard quotient (HQ), hazard index (HI), and maximum cumulative ratio (MCR), were used for the health risk assessment of the three phenols.

RESULTS

During this period, the change in LSGM HI was -2.9% per cycle [95% Cl: (-3.7%, -2.2%)], and the percentage of participants with HI > 0.1 decreased from 15.6% to 10.5%. Children (6-11 years) had higher mean HI values than adolescents (12-19 years), while female had higher LSGM HI values than male. MCR values were generally low and negatively correlated with HI. However, the average value of MCR increased from 1.722 to 2.107 during this period.

CONCLUSION

Exposure to phenolics among U.S. children and adolescents has changed in recent decades. However, gaps in data limit the interpretation of trends but legislative activity and advocacy campaigns by nongovernmental organizations may play a role in changing trends. Moreover, there are growing concerns about the potential health risks associated with exposure to multiple phenols in children and adolescents.

Occurrence and profile characteristics of environmental phenols in human urine from a rural area in Northwestern China

Many environmental phenols, such as bisphenols, benzophenones and parabens, are known as endocrine disruptors and can adversely affect human health. However, the knowledge of human exposure to common environmental phenols in Chinese rural areas is insufficient. In this context, 181 urine samples were collected from participants in a rural area in Northwest China and were analyzed for nine bisphenols, three benzophenones and four parabens. Bisphenol A (BPA), bisphenol S, benzophenone-1 (BP-1), benzophenone-3 (BP-3), 4-hydroxybenzophenone, methylparaben (MeP), ethylparaben and propylparaben (PrP) were detected in more than 50% of the urine samples, with median concentrations of 0.938 ng/mL, 0.0111 ng/mL, 0.191 ng/mL, 1.30 ng/mL, 0.0320 ng/mL, 25.9 ng/mL, 4.31 ng/mL and 1.94 ng/mL, respectively. A significant positive correlation was observed between BP-1 and BP-3, as well as between MeP and PrP, indicating metabolic transformation and combined use, respectively. The concentrations of MeP and PrP in females were significantly higher than those in males, suggesting that females were exposed to more MeP and PrP than males. Urinary concentrations of BPA, BP-3, MeP and PrP could be influenced by age. Other demographic information, such as annual household income, education and occupation was not associated with the exposure level of the targeted phenols in adults. The estimated daily intakes of the analytes except BPA were all below their respective tolerable/acceptable daily intake levels. This study profiles the demographic differences in the exposure to environmental phenols in general populations from rural areas and provides information on risk assessments.

Oxidative Stress and Apoptosis in Bisphenol AF-Induced Neurotoxicity in Zebrafish Embryos

Bisphenol AF (BPAF) is a structural counterpart of bisphenol A that is utilized in the food and beverage industry. The present study investigated the potential mechanisms in BPAF-induced neurotoxicity in zebrafish embryos. The BPAF concentrations (0.03, 0.1, 0.3, and 1.0 µM) had no obvious effect on hatching, mortality, and body length of zebrafish larvae, while curved tail and pericardial edema were observed in the 1.0 μM group at 72 and 96 h postfertilization (hpf). Locomotor activity of the larvae (at 120 hpf) significantly decreased from dark to light but increased from light to dark transitions in BPAF groups (0.1, 0.3, and 1.0 μM). Acridine orange showed that BPAF significantly increased green fluorescence protein intensity (22.6%) in the 1.0 μM group. Consistently, the induced apoptosis significantly up-regulated caspase 3 at 0.3 μM (1.95-fold) and 1.0 μM (2.26-fold) and bax at 0.3 μM (1.60-fold) and 1.0 μM (1.78-fold), whereas bcl-2 expression was significantly decreased at 0.3 μM (0.72-fold) and 1.0 μM (0.53-fold). In addition, increased reactive oxygen species concentrations at 0.3 μM (27%) and 1.0 μM (61.4%) resulted in suppressed superoxide dismutase and catalase activities. Moreover, quantitative polymerase chain reaction results showed that BPAF (0.3 and 1.0 μM) significantly altered normal dopaminergic signaling where dat was up-regulated, while drd2a and th1 were down-regulated, in a concentration-dependent manner. Aberrations in dopamine-related genes were congruous with the dysregulations in neurodevelopment genes (sox11b, pax6a, syn2a, and rob2). Our findings suggest that BPAF-evoked oxidative stress and apoptosis could translate into phenotypical behavioral and neurodevelopmental abnormalities. These highlights could provide theoretical reference for risk assessment and act as an early indicator to BPAF exposure. Environ Toxicol Chem 2022;41:2273-2284. © 2022 SETAC.

Bisphenol S Impairs Oestradiol Secretion during In Vitro Basal Folliculogenesis in a Mono-Ovulatory Species Model

Bisphenol S (BPS) affects terminal folliculogenesis by impairing steroidogenesis in granulosa cells from different species. Nevertheless, limited data are available on its effects during basal folliculogenesis. In this study, we evaluate in vitro the effects of a long-term BPS exposure on a model of basal follicular development in a mono-ovulatory species. We cultured ovine preantral follicles (180−240 μm, n = 168) with BPS (0.1 μM (possible human exposure dose) or 10 μM (high dose)) and monitored antrum appearance and follicular survival and growth for 15 days. We measured hormonal secretions (oestradiol (at day 13 [D13]), progesterone and anti-Müllerian hormone [D15]) and expression of key follicular development and redox status genes (D15) in medium and whole follicles, respectively. BPS (0.1 µM) decreased oestradiol secretion compared with the control (−48.8%, p < 0.001), without significantly impairing antrum appearance, follicular survival and growth, anti-Müllerian hormone and progesterone secretion and target gene expression. Thus, BPS could also impair oestradiol secretion during basal folliculogenesis as it is the case during terminal folliculogenesis. It questions the use of BPS as a safe BPA substitute in the human environment. More studies are required to elucidate mechanisms of action of BPS and its effects throughout basal follicular development.

Long-term exposure of zebrafish to bisphenol F: Adverse effects on parental reproduction and offspring neurodevelopment

Bisphenol F (BPF), an alternative to bisphenol A (BPA) has potential endocrine and reproductive toxicity; however, the effects of environmental concentrations of BPF on the reproductive and developmental toxicity of offspring following parental exposure to BPF remain unclear. In the present study, the effects of life-cycle BPF exposure at environmental concentrations on zebrafish reproduction, offspring growth, and development were investigated. The results showed that the life-cycle of BPF exposure significantly elevated oxidative stress levels, increased gonadal apoptosis, and reduced zebrafish (F0) spawning. Notably, through maternal transfer, BPF exposure significantly affected offspring development. Developmental parameters such as hatching rate, spontaneous movements, heart rate, body length, and locomotor behavior decreased in zebrafish larvae (F1). In addition, the expression levels of genes related to oxidative stress, apoptosis, and neurodevelopment were altered in F1 larvae. Therefore, the present study provides evidence that BPF, even at environmental concentrations, can be potentially adverse in terms of reproductive defects and offspring neurodevelopmental disorders. Therefore, BPF, as a substitute for BPA, is worthy of in-depth evaluation.

Bisphenol A and its analogues in paired urine and house dust from South China and implications for children's exposure

Following the restriction of bisphenol A (BPA) in certain products, a number of bisphenol analogues (BPs) have been used as BPA replacements in different applications, raising environmental and health concerns. The present study determined a total of 13 bisphenol analogues in house dust and children urine from South China families (n = 46). Among all BPs, BPA, bisphenol S (BPS) and bisphenol F (BPF) were frequently detected in house dust, with concentrations ranging from 0.54 to 26.2 μg/g (median: 2.60 μg/g), 0.07-11.5 μg/g (median: 0.32 μg/g) and 0.02-2.4 μg/g (median: 0.29 μg/g), respectively. BPA (median: 2.43 ng/mL) was also the dominant BP in children urine samples, accounting for 75.2 ± 27.4% of the total concentrations of urinary BPs, followed by BPS (0.23 ng/mL), whereas BPF was only detected in less than 30% of urine samples. Children's daily intake of bisphenols through dust ingestion and total daily intakes were estimated based on the dust and urine concentrations, respectively. The estimated intake of BPA, BPS and BPF via house dust ingestion accounted for 9%, 12% and 38% of the total intakes predicted based on urinary concentrations, respectively, and exhibited very low exposure risks.

Exposure of preschool-aged children to highly-concerned bisphenol analogues in Nanjing, East China

Bisphenol analogues (BPs) have already attracted wide concern owing to the environmental and health risks they pose. The exposure pathways and health risk of preschool-aged children to BPs, however, are still poorly understood. In this study, we choose population survey with 184 preschool-age children from a suburb of Nanjing, eastern China, further reveal the internal and external exposures concentrations, distribution profiles, potential sources and eventually assess health risk of preschool-age children to eight kinds of BPs. The results verify that the 95th percentile (P95) concentrations of Ʃ8BPs ranged from 0.27 to 41.6 ng/mL, with a median concentration of 7.83 ng/mL in the urine samples. BPA, and BPF were the predominant BPs in urine, accounting for 67.3%, and 18.0% of Ʃ8BPs. The urine-based estimated daily intake (EDI) of Ʃ8BPs was 187 ng/kg body weight/day. Similarly, BPA, and BPF were the main BPs in the environmental exposure sources, accounting for 80.8%, and 11.7% of the total BPs. Moreover, the total external exposure dose of Ʃ8BPs via the environmental sources was 68.1 ng/kg body weight/day, including BPA (56 ng/kg body weight/day), BPF (7.68 ng/kg body weight/day) and BPB (2.62 ng/kg body weight/day). The oral intake of drinking water and food (vegetables and rice) was the main exposure pathways of BPs in preschool-age children. Furthermore, the hazard quotient (HQ) of BPs have been evaluated and the results show no occurrence of high risk. Additionally, the urine-based EDI was significantly higher than the total external exposure dose, suggesting the existence of other pathways of BP exposure to be further explored. To the best of our knowledge, this is the first study to conduct both an internal and external exposure assessment of BPs.

The internal exposure of bisphenol analogues in South China adults and the associated health risks

Bisphenol A (BPA) is widely applied in industrial products and household products, leading to ubiquitous occurrences in environmental and biological samples. However, knowledge on human internal exposure to bisphenol analogues remains limited. Our study determined nine bisphenol analogues in urine samples collected from 1168 South China adults. BPA and bisphenol F (BPF) exhibited the highest detection frequencies in urine, i.e., 99.4% and 74.6%, respectively. BPA dominated over other analogues, with a median concentration of 1.74 μg/L, while BPF had a median concentration of 0.08 μg/L. Significant positive correlation was observed between urinary BPA and BPF (r = 0.201, p < 0.01), indicating similar exposure sources or pathways of these two chemicals. Urinary BPA concentrations were significantly correlated with age, marital status, drinking status and history of hyperlipidemia (p < 0.05). The median estimated daily intake (EDI) of Σ₃BPs (the sum concentrations of BPA, BPF and BPAF) was determined to be 53.6 ng/kg-bw/day for adults. The EDIs were much lower than the temporary tolerable reference dose of BPA recommended by the European Food Safety Authority, indicating the bisphenol analogues presented no obvious health risks to South China adults.

Protective Effects of Lignin-Carbohydrate Complexes from Wheat Stalk against Bisphenol a Neurotoxicity in Zebrafish via Oxidative Stress

Lignin-carbohydrate complexes (LCCs) from different lignocellulosic biomass have shown biological qualities as antioxidant and immunostimulant. By contrast, the application of LCCs as protectant against neurotoxicity caused by different compounds is scarce. In this work, two kinds of LCCs with carbohydrate-rich and lignin-rich fractions were obtained from wheat stalk and used to protect against BPA-neurotoxicity in zebrafish. The results showed that BPA at a concentration of 500 µg/L results in neurotoxicity, including significant behavioral inhibition, and prevents the expression of central nervous system proteins in transgenic zebrafish models (Tg (HuC-GFP)). When the zebrafish was treated by LCCs, the reactive oxygen species of zebrafish decreased significantly with the change of antioxidant enzymes and lipid peroxidation, which was due to the LCCs' ability to suppress the mRNA expression level of key genes related to nerves. This is essential in view of the neurotoxicity of BPA through oxidative stress. In addition, BPA exposure had negative effects on the exercise behavior, the catalase (CAT) and superoxide dismutase (SOD) activity, and the larval development and gene expression of zebrafish larvae, and LCC preparations could recover these negative effects by reducing oxidative stress. In zebrafish treated with BPA, carbohydrate-rich LCCs showed stronger antioxidant activity than lignin-rich LCCs, showing their potential as a neuroprotective agents.

A simple, rapid and sensitive method for the simultaneous determination of eighteen environmental phenols in human urine

Environmental phenols are a typical group of endocrine disrupting compounds (EDCs) and have caused growing concerns upon the potential adverse effects on humans. Urinary concentrations of phenols can be used as valid biomarkers for the assessment of human exposure. A method was developed for the simultaneous determination of eighteen environmental phenols (six parabens, seven bisphenols, four benzophenones and triclosan) in human urine using liquid-liquid extraction (LLE) coupled to high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The optimized LLE was time saving and required low volumes of organic solvents. A volume of only 0.2 mL urine sample was extracted and analyzed. The method yielded good linearity (0.9925-0.9994) and satisfactory limit of detection (LOD) (≤0.08 ng mL^-1). The relative recoveries ranged between 76.7% and 116% at three spiked levels, with intra- and inter-day precision less than 8.04% and 13.5%, respectively. Our method has been proved to be simple, rapid and sensitive by a comprehensive comparison between methods. This proposed method provides a large-scale biomonitoring tool for exposure assessment of human population to environmental phenols.

Environmental Estrogens and Their Biological Effects through GPER Mediated Signal Pathways

Many environmental chemicals have been found to exert estrogenic effects in cells and experimental animals by activating nuclear receptors such as estrogen receptors and estrogen-related receptors. These compounds include bisphenols, pesticides, polybrominated diphenyl ethers (PBDEs), organophosphate flame retardants, phthalates and metalloestrogens. G protein-coupled estrogen receptor (GPER) exists widely in numerous cells/tissues of human and other vertebrates. A number of studies have demonstrated that GPER plays a vital role in mediating the estrogenic effects of environmental pollutants. Even at very low concentrations, these chemicals may activate GPER pathways, thus affect many aspects of cellular functions including proliferation, metastasis and apoptosis, resulting in cancer progression, cardiovascular disorders, and reproductive dysfunction. This review summarized the environmental occurrence and human exposure levels of these pollutants, and integrated current experimental evidence toward revealing the underlying mechanisms of pollutant-induced cellular dysfunction via GPER. The GPER mediated rapid non-genomic actions play an important role in the process leading to the adverse effects observed in experimental animals and even in human beings.

Exposure of Slovenian children and adolescents to bisphenols, parabens and triclosan: Urinary levels, exposure patterns, determinants of exposure and susceptibility

Chemicals such as bisphenols, parabens and triclosan are endocrine disrupting chemicals. They are used in a wide variety of consumer products, making human exposure to those chemicals widespread. In the present study, levels of three bisphenols (bisphenol A, F and S), 7 parabens (methyl-, ethyl-, isopropyl-, propyl-, isobutyl-, butyl-, benzyl paraben) and triclosan were measured in first morning void from 246 Slovenian children and adolescents, aged 6-9 and 11-15 years and living in a rural region of Slovenia. Median levels of specific-gravity corrected levels for bisphenol A, bisphenol F, methyl paraben and ethyl paraben were 1.9, 0.085, 5.4 and 2.5 µg/L for children and 1.6, 0.11, 7.2 and 6.0 µg/L for adolescents, respectively. Median levels for all other endocrine disrupting chemicals were < LOQ. The levels are comparable with the levels reported in studies across the world. Exposure was age, sex, and location specific. Higher levels of bisphenol F and ethyl paraben were found in the samples of adolescents, while higher levels of methyl paraben were found in samples from girls. Furthermore, individuals living in one of the sampling locations, Goričko, were exposed to higher levels of bisphenol F and ethyl paraben than those in the remaining two sampling locations. Information about participants' dietary habits, use of food packaging and personal care products was obtained through questionnaires, and used to investigate associations between urinary levels of the biomarkers and potential exposure sources. High fat foods were associated with bisphenol A exposure, and cosmetics items such as lipstick and perfume with methyl paraben exposure. Significant correlation between methyl- and propyl paraben was observed in children's samples, suggesting similar exposure sources, while other compounds were not largely correlated, indicating independent sources. Furthermore, association between a single nucleotide polymorphism (SNP) in UGT2B15 gene and urinary levels of methyl and ethyl paraben was observed, showing the role of UGT2B15 isoform in methyl and ethyl paraben metabolism as well as indicating the SNP rs1902023 as a potential biomarker of susceptibility to adverse effects caused by the exposure. The present study reports exposure of children and adolescents in Slovenia to a wide range of different endocrine disrupting chemicals for the first time, connecting it to exposure patterns and exposure sources. The study is to the authors' knowledge the first that investigates direct connection between levels of urinary endocrine disrupting chemical biomarkers and genetic polymorphism in UGT2B15.

The internal exposure of phthalate metabolites and bisphenols in waste incineration plant workers and the associated health risks

Many hazardous substances can be released during incineration of municipal solid waste (MSW), which pose a potential threat to human health. As additives, phthalates (PAEs) and bisphenols (BPs), which are widely used in daily goods, are likely to be present in the released hazardous substances. In the present study, we investigated the urinary levels of phthalate metabolites (mPAEs) and BPs in workers in an MSW incineration plant (the exposed group) and in residents 8 km away (the control group) in Shenzhen, China. The results showed that the median total urinary concentration of mPAEs in workers was significantly higher than that in residents (1.02 × 10³ vs. 375 ng/mL). However, there was no significant difference between workers and residents for BPs. Among the mPAEs measured, the most abundant compound was mono-n-butyl phthalate in both exposed and control groups. Monoethyl phthalate and monomethyl phthalate might be potential markers for MSW incineration because of significantly high levels in the exposed group. The workers engaged in different types of workshops showed no significant differences in the urinary levels of mPAEs, also for BPs. It was worth noting that 70.8% of workers were at risk of the non-carcinogenic effects caused by PAEs with diethylhexyl phthalate having the highest risk. Actions should be taken to reduce the risks caused by these hazardous chemicals.

Oxidative stress in bisphenol AF-induced cardiotoxicity in zebrafish and the protective role of N-acetyl N-cysteine

Research has shown that there is a relationship between bisphenol A (BPA) exposure and the incidence of cardiovascular diseases. However, the effect of bisphenol AF (BPAF), a main substitute for BPA, on heart development remains unclear. In this study, the cardiotoxicity of BPAF was evaluated in zebrafish in vivo and in human cardiac myocytes (HCMs) in vitro. Our results showed that BPAF at a concentration of 200 μg/L results in cardiotoxicity, including a reduced number of cardiomyocytes and endocardial cells in the heart, and reduced heart size in two transgenic zebrafish models (myl7:: dsred2-nuc and fli1a::nGFP). An increase in apoptosis was observed along with antioxidant enzyme inhibition and lipid peroxidation. In addition, the mRNA expression levels of several key genes involved in cardiac development were suppressed by BPAF treatment. In the HCM cell model, BPAF at 2 mg/L induced reactive oxygen species generation, antioxidant enzyme inhibition, mitochondrial dysfunction and oxidative DNA damage. These adverse outcomes can be attenuated by the antioxidant N-acetyl-L-cysteine (NAC), suggesting that oxidative stress is involved in BPAF-induced cardiotoxicity. These data indicated that BPAF exposure increased oxidative stress and apoptosis and that it suppressed the expression of genes involved in cardiac development, which may play crucial roles in the mechanisms of BPAF-induced cardiotoxicity.

Occurrence of bisphenol A and its alternatives in paired urine and indoor dust from Chinese university students: Implications for human exposure

Bisphenol analogs (BPs), as the industrial chemicals, are widely used in consumer products. Limited information exists regarding human exposure to BPs in university students in China. In this study, we detected concentrations of seven BPs, namely bisphenol A (BPA), bisphenol AF (BPAF), bisphenol P (BPP), bisphenol AP (BPAP), bisphenol Z (BPZ), bisphenol S (BPS), and bisphenol F (BPF), in paired urine (n = 160) and indoor dust samples (n = 40) from university students in South China. High detection rates and levels (median) was found in BPA in paired urine (99%, 3.57 ng/mL) and indoor dust (80%, 2.98 μg/g) samples, followed by BPS (88%, 0.24 ng/mL; 78%, 0.22 μg/g). These findings suggest that BPA remains the major BPs used in consumer products. A positive relationship between urinary ∑BPs (sum of six BPs) concentration and indoor dust was observed (r = 0.444, p < 0.01), indicated that exposure to non-dietary BPs may also be significant to human exposure. The median EDI_urine values (ng/kg bw/day) of ∑BPs in males (119.6) were relatively higher than (p < 0.05) those in females (84.6). By contrast, the median EDI_dust of BPs (except for BPAF) in dust form female dormitories were slightly higher than that in dust from male dormitories. Notably, BPF was the most ingested from indoor dust (dormitory dust). This study is the first time to document the occurrence of BPs in paired urine and indoor dust in university students from China.