Reliable quantification of bisphenol A and its chlorinated derivatives in human breast milk using UPLC–MS/MS method

Effects of trichlorobisphenol A on the expression of proteins and genes associated with puberty initiation in GT1-7 cells and the relevant molecular mechanism

This study evaluated the effects of Cl3BPA on kisspeptin-G-protein coupled receptor 54 (GPR54)/gonadotropin-releasing hormone (GnRH) (KGG) signals and analyzed the roles of estrogen receptor alpha (ERɑ) and G-protein coupled estrogen receptor 1 (GPER1) in regulating KGG signals. The results showed that Cl3BPA at 50 μM increased the levels of intracellular reactive oxygen species (ROS) and GnRH, upregulated the protein levels of kisspeptin and the expression of fshr, lhr and gnrh1 genes related to KGG in GT1-7 cells. In addition, 50 μM Cl3BPA significantly upregulated the phosphorylation of extracellular regulated protein kinases 1/2 (Erk1/2), the protein levels of GPER1 and the expression of the gper1 as well as the most target genes associated with mitogen-activated protein kinase (MAPK)/Erk1/2 pathways. Specific signal inhibitor experiments found that Cl3BPA activated KGG signals by activating the GPER1-mediated MAPK/Erk1/2 signaling pathway at the mRNA level. A docking test further confirmed the interactions between Cl3BPA and GPER1. The findings suggest that Cl3BPA might induce precocious puberty by increasing GnRH secretion together with KGG signaling upregulation, which is driven by GPER1-mediated signaling pathway. By comparison, ClxBPAs with fewer chlorine atoms had more obvious effects on the expression of proteins and partial genes related to KGG signals in GT1-7 cells.

Estrogens and endocrine-disrupting chemicals differentially impact the bioenergetic fluxes of mammary epithelial cells in two- and three-dimensional models

Due to its sensitivity to hormonal signaling, the mammary gland is often referred to as a sentinel organ for the study of endocrine-disrupting chemicals (EDCs), environmental pollutants that can interfere with the estrogen signaling pathway and induce mammary developmental defects. If and how EDCs impact mammary epithelial cell metabolism has not yet been documented. Herein, to study how estrogens and EDCs modulate mammary gland metabolism, we performed bioenergetic flux analyses using mouse mammary epithelial organoids compared to cells grown in monolayer culture. Several EDCs were tested, including bisphenol A (BPA), its close derivative BPS, a new BPA replacement copolyester called TritanTM, and the herbicide glyphosate. We report that estrogens reprogrammed mammary epithelial cell metabolism differently when grown in two- and three-dimensional models. Specific EDCs were also demonstrated to alter bioenergetic fluxes, thus identifying a new potential adverse effect of these molecules. Notably, organoids were more sensitive to low EDC concentrations, highlighting them as a key model for screening the impact of various environmental pollutants. Mechanistically, transcriptomic analyses revealed that EDCs interfered with the regulation of estrogen target genes and the expression of metabolic genes in organoids. Furthermore, co-treatment with the anti-estrogen fulvestrant blocked these metabolic impacts of EDCs, suggesting that, at least partially, they act through modulation of the estrogen receptor activity. Finally, we demonstrate that mammary organoids can be used for long-term studies on EDC exposure to study alterations in organogenesis/morphogenesis and that past pregnancies can modulate the sensitivity of mammary epithelial organoids to specific EDCs. Overall, this study demonstrates that estrogens and EDCs modulate mammary epithelial cell metabolism in monolayer and organoid cultures. A better understanding of the metabolic impacts of EDCs will allow a better appreciation of their adverse effects on mammary gland development and function.

Quantification of the Conjugated Forms of Dichlorobisphenol A (3,3'-Cl 2 BPA) in Rat and Human Plasma Using HPLC-MS/MS

BACKGROUND

Bisphenol A (BPA) is a ubiquitous contaminant that has endocrine-disrupting effects. Chlorinated derivatives of BPA are formed during chlorination of drinking water and have higher endocrine-disrupting activity. Dichlorobisphenol A (Cl 2 BPA) is the most abundant chlorinated BPA derivative found in several human biological matrices. Recent in vitro experiments have shown that Cl 2 BPA is metabolized in sulpho- and glucuro-conjugated compounds. To date, no assay has been developed to quantify the sulfo- and glucuro-conjugates of 3,3'-Cl 2 BPA (3,3'-Cl 2 BPA-S and 3,3'-Cl 2 BPA-G, respectively).

METHODS

A high-performance liquid chromatography-tandem mass spectrometry assay for the determination of 3,3'-Cl 2 BPA conjugated forms in plasma samples was developed and validated according to the European Medicines Agency guidelines. Quantification was performed in the multiple reaction monitoring mode for all target analytes using a SCIEX 6500 + tandem mass spectrometer with an electrospray source operating in the negative ionization mode. Chromatographic separation was achieved using a C18 column maintained at 40°C and a binary mobile phase delivered in the gradient mode at a flow rate of 0.35 mL/min. Sample was prepared via simple precipitation using acetonitrile. The assay was validated and applied to rat and human plasma samples.

RESULTS

Linearity was demonstrated over the range of 0.006-25 ng/mL for 3,3'-Cl 2 BPA-G and 0.391-100 ng/mL for 3,3'-Cl 2 BPA-S. Intraday and interday bias values were in the 95%-109% range, and the imprecision <9%. Internal standard corrected matrix effects were also investigated. This method enabled quantification of the conjugated forms of 3,3'-Cl 2 BPA in plasma samples.

CONCLUSIONS

This is the first report on the development and validation of an analytical method for the quantification of 3,3'-Cl 2 BPA-G and 3,3'-Cl 2 BPA-S in the plasma matrix. This study is also the first report on the in vivo occurrence of these metabolites.

Challenges in the Analytical Preparation of a Biological Matrix in Analyses of Endocrine-Disrupting Bisphenols

Endocrine-disrupting chemicals (EDCs) are xenobiotics presented in a variety of everyday products that may disrupt the normal activity of hormones. Exposure to bisphenol A as EDC at trace and ultra-trace levels is associated with adverse health effects, and children are recognized as the most vulnerable group to EDCs exposure. In this review, a summary is presented of up-to-date sample preparation methods and instrumental techniques applied for the detection and quantification of bisphenol A and its structural analogues in various biological matrices. Biological matrices such as blood, cell-free blood products, urine, saliva, breast milk, cordial blood, amniotic and semen fluids, as well as sweat and hair, are very complex; therefore, the detection and later quantification of bisphenols at low levels present a real analytical challenge. The most popular analytical approaches include gas and liquid chromatography coupled with mass spectrometry, and their enhanced reliability and sensitivity finally allow the separation and detection of bisphenols in biological samples, even as ultra-traces. Liquid/liquid extraction (LLE) and solid-phase extraction (SPE) are still the most common methods for their extraction from biological matrices. However, many modern and environmentally safe microextraction techniques are currently under development. The complexity of biological matrices and low concentrations of analytes are the main issues for the limited identification, as well as understanding the adverse health effects caused by chronical and ubiquitous exposure to bisphenols and its analogues.

Chlorobisphenol A activated kisspeptin/GPR54-GnRH neuroendocrine signals through ERα and GPER pathway in neuronal GT1-7 cells

Chlorobisphenol A (Cl_xBPA) is a kind of novel estrogenic compounds. The present study aims to investigate the effects of three Cl_xBPA compounds on the kisspeptin/G protein-coupled receptor 54 (GPR54, also named KissR1)-gonadotropin-releasing hormone (GnRH) (KGG) system in neuronal GT1-7 cells with mechanistic insights by estrogen receptor signaling pathways. The study demonstrated that low-concentration Cl_xBPA induced the cell proliferation, promoted GnRH secretion, upregulated the expression of KGG neuroendocrine signal-related proteins (KissR1, GnRH1 and kisspeptin) and genes including Kiss1, GnRH1, KissR1, luteinizing hormone receptor (Lhr) and follicle-stimulating hormone receptor (Fshr) in GT1-7 cells. Additionally, Cl_xBPA activated nuclear estrogen receptor alpha (ERα) and member estrogen receptor G protein-coupled estrogen receptor (GPER)-regulated phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) and extracellular signal-regulated kinase (Erk1/2) signaling pathways. Pretreatment of GT1-7 cells with GPER inhibitor G15 and ERα inhibitor ICI reduced the expression of KissR1, GnRH1 and kisspeptin proteins, attenuated mRNA levels of Kiss1, GnRH1, KissR1, Fshr and Lhr genes, and decreased Cl_xBPA-induced GT1-7 cell proliferation. The results suggested that Cl_xBPA activated the KGG neuroendocrine signals and induced the proliferation of GT1-7 cells via ERα and GPER signaling pathways. This study provides a new perspective to explore the neuroendocrine toxicity mechanism of Cl_xBPA. CAPSULE: Cl_xBPA activated KGG neuroendocrine signaling pathway via ERα and GPER and induced the proliferation of GT1-7 cells.

Concentrations of bisphenols, parabens, and benzophenones in human breast milk: A systematic review and meta-analysis

BACKGROUND

Breast milk is the main source of nutrition for infants but may be responsible for their exposure to environmental chemicals, including endocrine-disrupting chemicals.

AIM

To review available evidence on the presence and concentrations of bisphenols, parabens (PBs), and benzophenones (BPs) in human milk and to explore factors related to exposure levels.

METHODS

A systematic review was carried out using Medline, Web of Science, and Scopus databases, conducting a comprehensive search of peer-reviewed original articles published during the period 2000-2020, including epidemiological and methodological studies. Inclusion criteria were met by 50 studies, which were compiled by calculating weighted detection frequencies and arithmetic mean concentrations of the chemicals. Their risk of bias was assessed using the ROBINS-I checklist.

RESULTS

Among the 50 reviewed studies, concentrations of bisphenols were assessed by 37 (74.0%), PBs by 21 (42.0%), and BPs by 10 (20.0%). Weighted detection frequencies were 63.6% for bisphenol-A (BPA), 27.9-63.4% for PBs, and 39.5% for benzophenone-3 (BP-3). Weighted mean concentrations were 1.4 ng/mL for BPA, 0.2-14.2 ng/mL for PBs, and 24.4 ng/mL for BP-3. Mean concentrations ranged among studies from 0.1 to 3.9 ng/mL for BPA, 0.1 to 1063.6 ng/mL for PBs, and 0.5 to 72.4 ng/mL for BP-3. The highest concentrations of BPA and PBs were reported in samples from Asia (versus America and Europe). Higher BPA and lower methyl-paraben concentrations were observed in samples collected after 2010. Elevated concentrations of these chemicals were associated with socio-demographic and lifestyle factors in eight studies (16.0%). Two epidemiological studies showed moderate/serious risk of bias.

CONCLUSIONS

This systematic review contributes the first overview of the widespread presence and concentrations of bisphenols, PBs, and BPs in human breast milk, revealing geographical and temporal variations. The methodological heterogeneity of published studies underscores the need for well-conducted studies to assess the magnitude of exposure to these chemicals from human milk.

Bisphenol-A in biological samples of breast cancer mastectomy and mammoplasty patients and correlation with levels measured in urine and tissue

Endocrine disrupting chemicals (EDCs) are organic compounds that have estrogenic activity and can interfere with the endocrine system. Bisphenol-A (BPA) is one of these compounds which possess a potential risk for breast cancer. The aim of this research was to evaluate BPA concentration in both the urine and breast adipose tissue samples of breast cancer mastectomy and mammoplasty patients and study correlations of BPA levels in breast adipose tissue with urine samples in the both groups. Urine and breast adipose tissue samples from 41 breast cancer mastectomy and 11 mammoplasty patients were taken. BPA concentrations were detected using an ELISA assay. Urinary BPA concentrations were significantly higher in cancerous patients (2.12 ± 1.48 ng/ml; P < 0.01) compared to non-cancerous (0.91 ± 0.42 ng/ml). Likewise, tissue BPA concentrations in cancerous patients (4.20 ± 2.40 ng/g tissue; P < 0.01) were significantly higher than non- cancerous (1.80 ± 1.05 ng/g tissue). Urinary BPA concentrations were positively correlated with breast adipose tissue BPA in the case group (P < 0.001, R = 0.896). We showed that BPA was present in urine and breast adipose tissue samples of the studied populations. With regard to higher BPA mean concentration in cancerous patients than non-cancerous individuals in this study, BPA might increase the risk of breast cancer incidence.

An overview of the literature on emerging pollutants: Chlorinated derivatives of Bisphenol A (ClxBPA)

CONTEXT

Bisphenol A (BPA) is a ubiquitous contaminant with endocrine-disrupting effects in mammals. During chlorination treatment of drinking water, aqueous BPA can react with chlorine to form chlorinated derivatives of BPA (mono, di, tri and tetra-chlorinated derivatives) or Cl_xBPA.

OBJECTIVE

The aim of this study is to summarize and present the state of knowledge on human toxicological risk assessment of Cl_xBPA.

MATERIALS AND METHODS

A search on Cl_xBPA in the PubMed database was performed based on studies published between 2002 and 2021. Forty-nine studies on chlorinated derivatives of BPA were found. Available information on their sources and levels of exposure, their effects, their possible mechanisms of action and their toxicokinetics data was extracted and presented.

RESULTS

Cl_xBPA have been essentially detected in environmental aqueous media. There is evidence in toxicological and epidemiological studies that Cl_xBPA also have endocrine-disrupting capabilities. These emerging pollutants have been found in human urine, serum, breast milk, adipose and placental tissue and can constitute a risk to human health. However, in vitro and in vivo toxicokinetic data on Cl_xBPA are scarce and do not allow characterization of the disposition kinetics of these compounds.

CONCLUSION

More research to assess their health risks, specifically in vulnerable populations, is needed. Some water chlorination processes are particularly hazardous, and it is important to evaluate their chlorination by-products from a public health perspective.

S-TiO2/UiO-66-NH2 composite for boosted photocatalytic Cr(VI) reduction and bisphenol A degradation under LED visible light

Series sulfur-doped TiO₂/amine-functionalized zirconium metal organic frameworks (S-TiO₂/UiO-66-NH₂) composites (U1Tx) were facilely fabricated from the as-prepared S-TiO₂ and UiO-66-NH₂ via ball-milling method. The photocatalytic activities of U1Tx toward Cr(VI) reduction and bisphenol A (BPA) degradation were tested under low-power LED visible light. The results demonstrated that U1T3 exhibited better photocatalytic performances than the pristine S-TiO₂ and UiO-66-NH₂ due to the improved separation and migration of electrons and holes. Furthermore, the influence factors like pH values and foreign ions on the photocatalytic performances of U1Tx were also investigated. The Box-Behnken design methodology was utilized to further clarify that the inorganic foreign anions and dissolved organic matters could exert significant effects on photocatalytic Cr(VI) reduction performance. As well, the possible pathway of BPA degradation was depicted. After four runs of Cr(VI) removal, it was found that U1T3 exhibited preferable reusability and water stability. The probable reaction mechanism was proposed and verified by active species capture experiments, electron spin resonance determination and electrochemical analyses.

Simultaneous determination of bisphenol A and its chlorinated derivatives in human plasma: Development, validation and application of a UHPLC-MS/MS method

Bisphenol A (BPA) is a well-known ubiquitous chemical found in polycarbonate, polysulfone and epoxy resins, used in mass production for many consumer products. BPA exhibits endocrine disruptor properties that can potentially induce adverse health effects. In aquatic environments, it can react with chlorine to produce chlorinated derivatives (ClxBPAs). ClxBPAs exhibit oestrogenic activity 10 to 105 times higher than BPA itself. Assessing human exposure to endocrine disrupting chemicals is mandatory to assess health risk. Blood, as well as urine matrix, are commonly used to perform human biomonitoring. We therefore developed, fully validated and applied a method based on Ultra High Performance Liquid Chromatography couples to a Triple Quad Mass Spectrometer to determine BPA, monochlorobisphenol A (MCBPA), dichlorobisphenol A (DCBPA), trichlorobisphenol A (TCBPA) and tetrachlorobisphenol A (TTCBPA) in human blood plasma. The European Medicines Agency guidelines for bioanalytical method validation have been applied. Precision and trueness of the method were <15% at medium and high levels of quality control and <20% at the limits of quantification (LOQs). The LOQs were settled at 0.1 ng/mL for BPA, 0.02 ng/mL for TTCBPA and 0.005 ng/mL for MCBPA, DCBPA, and TCBPA. The analytical method was applied to ten patients suffering from end stage renal disease. BPA was quantified in all ten patients while MCBPA, DCBPA and TTCBPA were determined in three and TCBPA in four. In conclusion, we have successfully developed a highly sensitive method to determine BPA and ClxBPAs in human plasma. Thanks to this method, for the first time, we could demonstrate ClxBPAs occurrence in human blood.

Overexposure to Bisphenol A and Its Chlorinated Derivatives of Patients with End-Stage Renal Disease during Online Hemodiafiltration

The health safety conditions governing the practice of online hemodiafiltration (OL-HDF) do not yet incorporate the risks related to the presence of endocrine disruptors such as bisphenol A (BPA). The aim of this study was to assess, for the first time, the exposure to BPA but also to its chlorinated derivatives (ClxBPA) (100 times more estrogenic than BPA) during OL-HDF. We demonstrated that BPA is transmitted by the different medical devices used in OL-HDF: ultrafilters, dialysis concentrate cartridges (and not only dialyzers, as previously described). Moreover, BPA has been found in dialysis water as well as in ultrapure dialysate and replacement fluid due to contamination of water coming from municipal network. Indeed, due to contaminations provided by both ultrafilters and water, high levels of BPA were determined in the infused replacement fluid (1033 ng.L⁻¹) from the beginning of the session. Thus, our results demonstrate that dialysis water must be considered as an important exposure source to endocrine disruptors, especially since other micropollutants such as ClxBPA have also been detected in dialysis fluids. While assessment of the impact of this exposure remains to be done, these new findings should be taken into account to assess exposure risks in end-stage renal disease patients.

Biomonitoring of bisphenols A, F, S in human milk and probabilistic risk assessment for breastfed infants

The present study addresses the presence of bisphenols A (BPA) and its analogs bisphenol F (BPF) and S (BPS) in milk of 120 mothers living in Valencia (Spain) and participating in the BETTERMILK project (year 2015). We also studied the factors that could influence the BPA levels and estimated the exposure and the risk for breast fed infants. The frequency of detection of total (conjugated + unconjugated) and unconjugated-BPA were 83% and 77%, with a geometric mean of 0.29 ng/mL and 0.15 ng/mL, respectively. The frequency of detection was much lower for total-BPF (22%) and total-BPS (1.1%). The place of residence of the mother and the use of personal care products showed significant association with BPA concentrations. The estimated daily intake of total-BPA for breastfed infants amounted to a geometric mean of 0.04 μg/kg bw and a 95th percentile of 1.0 μg/kg bw, below the tolerable daily intake of 4 μg/kg bw-day established by EFSA. To our knowledge, this is the largest biomonitoring study of bisphenols in human milk in Europe.

Development and validation of an LC-MS/MS method for the simultaneous determination of bisphenol A and its chlorinated derivatives in adipose tissue

Bisphenol A (BPA) and its chlorinated derivatives (Clx-BPA) are environmental pollutants exhibiting endocrine-disrupting (ED) properties suspected to be involved in the pathogenesis of hormone-dependent cancers, such as breast and prostate cancers. Due to their lipophilic properties, they may accumulate in adipose tissue which could therefore be a suitable matrix to assess long-term exposure to these compounds and relationships with the tumorigenesis of these cancers. An LC-MS/MS assay for the determination of BPA and Clx-BPA in adipose tissue samples was developed and fully validated according to current bioanalytical validation guidelines. Ionization was achieved using an electrospray source operating in the negative mode and quantification of target analytes was obtained in the multiple reaction monitoring mode. Both standard and quality control (QC) samples were prepared in blank adipose tissue samples. Linearity was demonstrated over the ranges 0.125 to 8.000 and 0.0125-0.8000 ng/mL for BPA and Clx-BPA, respectively. Accuracy and precision were demonstrated over the whole concentration range: intra and inter-day bias values were in the 85-114% range and imprecision of the method did not exceed 14%. Lower limits of quantification were validated using QCs at 0.1250 and 0.0125 ng/mL for BPA and Clx-BPA, respectively. Internal standard-corrected matrix effects were comparable in breast and prostate adipose tissues, demonstrating that this method could be used to reliably assay BPA and Clx-BPA in both tissues. The method was sensitive enough to determine BPA and Clx-BPA in breast adipose tissue obtained from women undergoing breast surgery, enabling identification of different patterns of exposure to these ED chemicals. The method enables the reliable quantification of BPA and Clx-BPA in adipose tissue and could be used to assess long-term exposure to these compounds and potential associations with hormone-dependent cancers.

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

Due to the extensive use in consumer products, the bisphenols (BPs) pollution in the environments has aggravated and people are frequently exposed to BPs. In this research, four BPs, i.e., bisphenol A (BPA), bisphenol F (BPF), bisphenol S (BPS) and bisphenol AF (BPAF), were determined in urine samples collected from Gaochun District preschool-age children and the concentrations, distribution profiles, potential sources and cumulative risk assessment of the target compounds were studied. Total concentrations of 4 BPs ranged from 2 to 3113.1 ng/L, with the average concentration of 648.6 ng/L. BPA was the predominant congener (accounting for 94%), followed by BPS. Correlation analysis indicated a negative relationship between BPA and BPAF (R = -0.273, p < 0.05). The estimated daily intakes suggested that young females were more sensitive to BPs. Moreover, the cumulative risk for hazard quotient (HQ) of BPA has been evaluated and the results showed that no high risk had occurred. It provided basic information on the occurrence and human exposure to urinary BPs of preschool aged children from Gaochun District.

Chlorinated and brominated bisphenol A derivatives: Synthesis, characterization and determination in water samples

Bisphenol A (BPA) has been used in the plastics industry for several decades. During the treatment of drinking water with chlorine reagent, the formation of chlorinated derivatives of BPA (ClxBPA) but also bromoBPA and bromochloroBPA is to be expected. Some of these compounds are considered to have an estrogenic effect and could induce major risks for human health by targeting different organs and systems in the body. In this paper, we describe the synthesis of chloro- and bromobisphenol A (ClxBPA, BrxBPA, BrxClxBPA)and their analytical characterization. These derivatives could be used as analytical standards in LC-MS/MS or evaluated in in vitro biological tests for their potential as endocrine disruptors. In this study, we evaluated the presence of BPA, ClxBPA in a pilot study from water samples. Range values found for BPA, ClxBPA were respectively 2.8-4169.3 ng/L and 0.8-11.3 ng/L.

Determination of bisphenol A in water and the medical devices used in hemodialysis treatment

Bisphenol A (BPA) is an endocrine disruptor found in food containers and plastic beverages and also in medical devices such as dialyzers. The aim of this study is while taking into account the BPA originating in medical devices and the water used in dialysate production, to provide the first published investigation of overall potential exposure to BPA during hemodialysis treatment in patients suffering from end-stage renal disease. BPA concentration in water (at each step of purification treatment) and in dialysate and BPA leaching from dialyzers were determined using solid-phase extraction coupled to ultra-high-performance-liquid chromatography tandem mass spectrometry. We have corroborated the hypothesis that a significant amount of BPA may migrate from dialyzers and also demonstrated that BPA is provided by the water used in dialysate production (8.0±5.2ngL(-1) on average) and by dialysis machine and dialysate cartridges, leading to dialysate contamination of 22.7±15.6ngL(-1) on average. Taking into account all the sources of BPA contamination that may come into play during a hemodialysis session, the highest exposure could reach an estimated 140ng/kg b.w./day for hemodialyzed patients, directly available for systemic exposure. Finally, BPA contamination should be taken into account as concerns both the medical devices commonly used in hemodialysis and purified water production systems.

Biomonitoring of human exposures to chlorinated derivatives and structural analogs of bisphenol A

The high reactivity of bisphenol A (BPA) with disinfectant chlorine is evident in the instantaneous formation of chlorinated BPA derivatives (ClxBPA) in various environmental media that show increased estrogen-activity when compared with that of BPA. The documented health risks associated with BPA exposures have led to the gradual market entry of BPA structural analogs, such as bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), etc. A suite of exposure sources to ClxBPA and BPA analogs in the domestic environment is anticipated to drive the nature and range of halogenated BPA derivatives that can form when residual BPA comes in contact with disinfectant in tap water and/or consumer products. The primary objective of this review was to survey all available studies reporting biomonitoring protocols of ClxBPA and structural BPA analogs (BPS, BPF, BPB, etc.) in human matrices. Focus was paid on describing the analytical methodologies practiced for the analysis of ClxBPA and BPA analogs using hyphenated chromatography and mass spectrometry techniques, because current methodologies for human matrices are complex. During the last decade, an increasing number of ecotoxicological, cell-culture and animal-based and human studies dealing with ClxBPA exposure sources and routes of exposure, metabolism and toxicity have been published. Up to date findings indicated the association of ClxBPA with metabolic conditions, such as obesity, lipid accumulation, and type 2 diabetes mellitus, particularly in in-vitro and in-vivo studies. We critically discuss the limitations, research needs and future opportunities linked with the inclusion of ClxBPA and BPA analogs into exposure assessment protocols of relevant epidemiological studies.

Global Assessment of Bisphenol A in the Environment: Review and Analysis of Its Occurrence and Bioaccumulation

Because bisphenol A (BPA) is a high production volume chemical, we examined over 500 peer-reviewed studies to understand its global distribution in effluent discharges, surface waters, sewage sludge, biosolids, sediments, soils, air, wildlife, and humans. Bisphenol A was largely reported from urban ecosystems in Asia, Europe, and North America; unfortunately, information was lacking from large geographic areas, megacities, and developing countries. When sufficient data were available, probabilistic hazard assessments were performed to understand global environmental quality concerns. Exceedances of Canadian Predicted No Effect Concentrations for aquatic life were >50% for effluents in Asia, Europe, and North America but as high as 80% for surface water reports from Asia. Similarly, maximum concentrations of BPA in sediments from Asia were higher than Europe. Concentrations of BPA in wildlife, mostly for fish, ranged from 0.2 to 13 000 ng/g. We observed 60% and 40% exceedences of median levels by the US Centers for Disease Control and Prevention's National Health and Nutrition Examination Survey in Europe and Asia, respectively. These findings highlight the utility of coordinating global sensing of environmental contaminants efforts through integration of environmental monitoring and specimen banking to identify regions for implementation of more robust environmental assessment and management programs.

New method for the determination of parabens and bisphenol A in human milk samples using ultrasound-assisted extraction and clean-up with dispersive sorbents prior to UHPLC-MS/MS analysis

A sensitive and accurate analytical method for the determination of methyl-, ethyl-, propyl- and butylparaben and bisphenol A in human milk samples has been developed and validated. The combination of ultrasound-assisted extraction (UAE) and a simplified and rapid clean-up technique that uses sorbent materials has been successfully applied for the preparation of samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The analytes were extracted from freeze-dried human milk samples using acetonitrile and ultrasonic radiation (three 15-min cycles at 70% amplitude), and further cleaned-up with C18 sorbents. The most influential parameters affecting the UAE method and the clean-up steps were optimized using design of experiments. Negative electrospray ionization (ESI) in the selected reaction monitoring (SRM) mode was used for MS detection. The use of two reactions for each compound allowed simultaneous quantification and identification in one run. The analytes were separated in less than 10min. Deuterium-labeled ethylparaben-d5 (EPB-d5) and deuterium-labeled bisphenol A-d16 (BPA-d16) were used as surrogates. The limits of quantification ranged from 0.4 to 0.7ngmL(-1), while inter- and intra-day variability was under 11.1% in all cases. In the absence of certified reference materials, recovery assays with spiked samples using matrix-matched calibration were used to validate the method. Recovery rates ranged from 93.8% to 112.2%. The proposed method was satisfactorily applied for the determination of four selected parabens and bisphenol A in human milk samples obtained from nursing mothers living in the province of Granada (Spain).

Determination of bisphenol A and related substitutes/analogues in human breast milk using gas chromatography-tandem mass spectrometry

Bisphenol A (BPA) is an industrial chemical widely used in the production of polycarbonate and epoxy resins. Identified as an endocrine-disrupting chemical (EDC), BPA is a matter of existing or ongoing restrictive regulations and then is increasingly being replaced by other analogues used as BPA's substitutes. Human biomonitoring studies focusing on both BPA and emerging related analogues consequently appear as a requirement either for documenting the efficiency of regulatory actions toward BPA and for fuelling incoming risk assessment studies toward BPA's substitutes. In particular, the increasing concern about the late effects consecutive to early exposures naturally identify human breast milk as a target biological matrix of interest for priority exposure assessment focused on critical sub-populations such as pregnant women, fetuses, and/or newborns. In this context, an accurate and sensitive analytical method based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was developed for the quantification of 18 "BPA-like" compounds in breast milk samples at trace levels (<0.05 μg kg(-1)). The method includes a preliminary protein precipitation step followed by two successive solid-phase extraction (SPE) stages. Quantification of the targeted compounds was achieved according to the isotopic dilution method using (13)C12-BPA as internal standard. The method was validated according to current EU guidelines and criteria. Linearity (R (2)) was better than 0.99 for each molecule within the concentration range 0-5 μg kg(-1). The detection and quantification limits ranged from 0.001 to 0.030 μg kg(-1) and from 0.002 to 0.050 μg kg(-1), respectively. The analytical method was successfully applied to the first set of human breast milk samples (n = 30) originating from French women in the Region Pays-de-la-Loire. The measured levels of BPA were found in the <LOQ-1.16 μg kg(-1) range. BPS was detected in only one sample at 0.23 μg kg(-1), while the other targeted molecules were not detected. The proposed methodology then appeared suitable for the further monitoring of a potential decrease of BPA levels and an increase of other BPA analogue levels as reflective of the expected incoming trend in terms of human exposure.

Influence of household cleaning practices on the magnitude and variability of urinary monochlorinated bisphenol A

Low-dose health effects of BPA have not been adequately explored in the presence of BPA metabolites of chlorinated structure that may exert larger estrogenic effects than those of their parent compound. We hypothesized that chlorine-containing cleaning products used in household cleaning activities could modify the magnitude of total urinary BPA concentration measurements via the production of chlorinated BPA (ClBPA) derivatives. Our objective was to investigate the influence of typical household cleaning activities (dishwashing, toilet cleaning, mopping, laundry, etc.) on the magnitude and variability of urinary total BPA and mono-ClBPA levels in the general adult population. A cross-sectional study (n=224) included an adult (≥18 years) pool of participants from the general population of Nicosia, Cyprus. First morning urine voids were collected, and administered questionnaires included items about household cleaning habits, demographics, drinking water consumption rates and water source/usage patterns. Urinary concentrations of total BPA (range: 0.2-82 μg L(-1)), mono-ClBPA (16-340 ng L(-1)), and total trihalomethanes (0.1-5.0 μg L(-1)) were measured using gas chromatography coupled with triple quadrupole mass spectrometry and large volume injection. Linear multiple regression analysis revealed that dishwashing along with age and gender (females) were able to predict urinary mono-ClBPA levels (ng g(-1)), even after adjusting for covariates; this was not the case for urinary total BPA levels (ng g(-1)). Significant (p<0.001) association was observed between urinary mono-ClBPA and THM levels, underlying the important role of disinfectant (chlorine) in promoting formation of both ClBPA and THM. Urinary mono-ClBPA levels were measured for the first time using an appreciable sample size, highlighting the co-occurring patterns of both total BPA and mono-ClBPA. Epidemiological studies and probabilistic BPA risk assessment exercises should consider assessing daily intake estimates for chlorinated BPA compounds, as well.

Bisphenol a and its chlorinated derivatives in human colostrum

The health effects related to bisphenol A (BPA) and its exposure sources have undergone extensive investigation, but no consensus has been reached. Hitherto, the major source of human BPA exposure considered in the literature remains food-contact material. However, the chlorine present in drinking water may react with BPA to form chlorinated derivatives (ClxBPA), which have indeed been shown to have a heightened level of estrogenic activity. In this study, we have evaluated colostrum concentrations of BPA and ClxBPA in order to confirm our hypothesis according to which BPA water contamination leads to ClxBPA human exposure. BPA and its ClxBPA were assessed through online solid-phase extraction coupled to ultra high-performance liquid chromatography tandem mass spectrometry (SPE-UPLC-MS/MS) using the isotope dilution method in the colostrums of 21 women who had completed a water exposure questionnaire. BPA was detected in 19 colostrums and its ClxBPA in 21 colostrums. Mean concentrations were 1.87 ± 1.38 ng mL(-1) (n = 19) for BPA, 1.87 ± 1.23 ng mL(-1) (n = 7) and 1.56 ± 0.74 (n = 18) ng mL(-1) for 2,2'-Cl2BPA and 2,6-Cl2BPA, respectively, and 0.68 ng mL(-1) (n = 1) for trichloro-BPA. These findings confirm our hypothesis that ClxBPA should be taken into account in human health risk assessment.

Mixtures of xenoestrogens disrupt estradiol-induced non-genomic signaling and downstream functions in pituitary cells

BACKGROUND

Our study examines the effects of xenoestrogen mixtures on estradiol-induced non-genomic signaling and associated functional responses. Bisphenol-A, used to manufacture plastic consumer products, and nonylphenol, a surfactant, are estrogenic by a variety of assays, including altering many intracellular signaling pathways; bisphenol-S is now used as a bisphenol-A substitute. All three compounds contaminate the environment globally. We previously showed that bisphenol-S, bisphenol-A, and nonylphenol alone rapidly activated several kinases at very low concentrations in the GH3/B6/F10 rat pituitary cell line.

METHODS

For each assay we compared the response of individual xenoestrogens at environmentally relevant concentrations (10-15 -10-7 M), to their mixture effects on 10-9 M estradiol-induced responses. We used a medium-throughput plate immunoassay to quantify phosphorylations of extracellular signal-regulated kinases (ERKs) and c-Jun-N-terminal kinases (JNKs). Cell numbers were assessed by crystal violet assay to compare the proliferative effects. Apoptosis was assessed by measuring caspase 8 and 9 activities via the release of the fluorescent product 7-amino-4-trifluoromethylcoumarin. Prolactin release was measured by radio-immunoassay after a 1 min exposure to all individual and combinations of estrogens.

RESULTS

Individual xenoestrogens elicited phospho-activation of ERK in a non-monotonic dose- (fM-nM) and mostly oscillating time-dependent (2.5-60 min) manner. When multiple xenoestrogens were combined with nM estradiol, the physiologic estrogen's response was attenuated. Individual bisphenol compounds did not activate JNK, while nonylphenol did; however, the combination of two or three xenoestrogens with estradiol generated an enhanced non-monotonic JNK dose-response. Estradiol and all xenoestrogen compounds induced cell proliferation individually, while the mixtures of these compounds with estradiol suppressed proliferation below that of the vehicle control, suggesting a possible apoptotic response. Extrinsic caspase 8 activity was suppressed by estradiol, elevated by bisphenol S, and unaffected by mixtures. Intrinsic caspase 9 activity was inhibited by estradiol, and by xenoestrogen combinations (at 10-14 and 10-8 M). Mixtures of xenoestrogens impeded the estradiol-induced release of prolactin.

CONCLUSIONS

In mixtures expected to be found in contaminated environments, xenoestrogens can have dramatic disrupting effects on hormonal mechanisms of cell regulation and their downstream functional responses, altering cellular responses to physiologic estrogens.