Determination of environmental estrogens in human urine by high performance liquid chromatography after fluorescent derivatization with p-nitrobenzoyl chloride

Effects of pharmaceutical and personal care products on pubertal development: Evidence from human and animal studies

Pharmaceutical and personal care products (PPCPs) include a wide range of drugs, personal care products and household chemicals that are produced and used in significant quantities. The safety of PPCPs has become a growing concern in recent decades due to their ubiquitous presence in the environment and potential risks to human health. PPCPs have been detected in various human biological samples, including those from children and adolescents, at concentrations ranging from several ng/L to several thousand μg/L. Epidemiological studies have shown associations between exposure to PPCPs and changes in the timing of puberty in children and adolescents. Animal studies have shown that exposure to PPCPs results in advanced or delayed pubertal onset. Mechanisms by which PPCPs regulate pubertal development include alteration of the hypothalamic kisspeptin and GnRH networks, disruption of steroid hormones, and modulation of metabolic function and epigenetics. Gaps in knowledge and further research needs include the assessment of environmental exposure to pharmaceuticals in children and adolescents, low-dose and long-term effects of exposure to PPCPs, and the modes of action of PPCPs on pubertal development. In summary, this comprehensive review examines the potential effects of exposure to PPCPs on pubertal development based on evidence from human and animal studies.

4-Azido-7-nitrobenzoxadiazole as innovative clickable fluorescence probe for trace and selective quantification of ethinylestradiol in human plasma

Quantification of ethinylestradiol (EE) in biological matrices is challenging as it is a very potent drug with a very low Cmax (75 pg.ml-1 ). Despite the high sensitivity of fluorometric methods, the detection of EE was confined because its structure exhibited very limited fluorescence. Therefore, it must be derivatized first using a fluorogenic agent to produce a more potent fluorescence derivative to achieve the desired ultrasensitive bioanalysis. Here, for the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole (NBD-AZ) to react with the alkyne group of EE, with the help of copper sulphate and l-ascorbic acid to give a highly fluorescent and stable 1,2,3-triazole derivative. Density functional theory calculation revealed how the triazole formation affects the quantum yield and fluorescence of click reaction product when compared with NBD-AZ. The resulting triazole exhibited a strong signal at a wavelength of 540 nm after excitation at 470 nm. Reaction parameters impacting the intensity of fluorescence were cautiously studied and optimized. The suggested approach has shown outstanding performance, high linearity (25-300 pg.ml-1 ) and a low detection limit of 7.5 pg.ml-1 . The enhanced sensitivity and selectivity were exploited for analyzing EE in plasma using liquid-liquid extraction for samples cleaning up without interference from any biological components and with a mean % recovery of 100.13 ± 0.39. Accuracy, sensitivity, selectivity, simplicity, and cost-effectiveness make this approach a convincing, promising, and appealing alternative to the reported analytical methods for EE bioanalysis in different matrices.

High Performance Liquid Chromatography (HPLC) with Fluorescence Detection for Quantification of Steroids in Clinical, Pharmaceutical, and Environmental Samples: A Review

Steroids are compounds widely available in nature and synthesized for therapeutic and medical purposes. Although several analytical techniques are available for the quantification of steroids, their analysis is challenging due to their low levels and complex matrices of the samples. The efficiency and quick separation of the HPLC combined with the sensitivity, selectivity, simplicity, and cost-efficiency of fluorescence, make HPLC coupled to fluorescence detection (HPLC-FLD) an ideal tool for routine measurement and detection of steroids. In this review, we covered HPLC-FLD methods reported in the literature for the steroids quantification in clinical, pharmaceutical, and environmental applications, focusing on the various approaches of fluorescent derivatization. The aspects related to analytical methodology including sample preparation, derivatization reagents, and chromatographic conditions will be discussed.

Nonylphenol exposure in 7-year-old Japanese children between 2012 and 2017- Estimation of daily intakes based on novel urinary metabolites

Nonylphenol (NP) has been under scrutiny for decades due to its endocrine-disrupting properties and its ubiquity in the environment. Despite its widespread occurrence, robust and reliable exposure data are rare. In this study, we used human biomonitoring (HBM) measuring the novel urinary alkyl-chain-oxidized biomarkers OH-NP and oxo-NP to determine NP exposure in 7-year-old Japanese children. The new biomarkers are advantageous over measuring unchanged NP because they are not prone to external contamination. We analyzed 180 first morning void urine samples collected between 2012 and 2017. OH-NP and oxo-NP were detected in 100% and 66% of samples at median concentrations of 2.69 and 0.36 µg/L, respectively. 10-fold concentration differences between OH-NP and oxo-NP are in line with recent findings on human NP metabolism. Based on OH-NP we back-calculated median and maximum NP daily intakes (DI) of 0.14 and 0.95 µg/(kg bw*d). These DIs are rather close to but still below the current provisional tolerable daily intake of 5 µg/(kg bw*d) by the Danish Environmental Protection Agency. Between 2012 and 2017 the DIs decreased by an average of 4.7% per year. We observed no seasonal changes or gender differences and questionnaire data on food consumption, housing characteristics or pesticide use showed no clear associations with NP exposure. Urinary OH-NP was weakly associated with the oxidative stress (lipid peroxidation) biomarkers N-ε-hexanoyl-lysine (HEL) and trans-4-hydroxy-2-nonenal (HNE) (Spearman ρ = 0.30 and 0.22, respectively), but not with 8-hydroxy-2'-deoxyguanosine (8-OHdG). Further research is needed to identify and understand the major sources of NP exposure and to investigate a potential role in oxidative stress. This study is the first to investigate NP exposure in Japanese children based on robust and sensitive HBM data. It is a first step to fill the long-standing gap in quantitative human NP exposure monitoring and risk assessment.

Exposure of bisphenol A in breast cancer patients-quantitatively assessed by sensitivity-enhanced high-performance liquid chromatography coupled with fluorescence detection: A case-control study

A simple, reproducible and sensitive liquid chromatography (HPLC) method has been developed and validated for estimation of bisphenol A (BPA) in human urine. A simple liquid-liquid extraction technique was used in BPA sample preparation. The analyte was chromatographed on a Shimadzu Prominence HPLC system using isocratic mobile phase conditions at a flow rate of 0.500 ml/min and a Hypersil Gold C₁₈ column maintained at 40°C. Quantification was performed on a fluorescence detector set at excitation 275 nm, emission 313 nm and bisphenol B was used as internal standard. The total run time was 8 min. The method was found to have acceptable sensitivity, selectivity, accuracy (98.82-103.64%), precision (1.17-5.36) and stability in the validation experiment carried out as per the USFDA guidelines. The method sensitivity was as low as 0.50 ng/ml. The applicability of the validated analytical method was established in human patient urine samples. The mean human urine BPA concentrations were 1.18 ± 2.11 ng/ml in the control group and 5.76 ± 6.00 ng/ml in the patient group (P < 0.001). Therefore, this method could be considered as an alternative for routine bio-monitoring of BPA which is less expensive and feasible in resource-poor settings.

Bract as a novel extraction phase in thin-film SPME combined with 96-well plate system for the high-throughput determination of estrogens in human urine by liquid chromatography coupled to fluorescence detection

In this study, an environmentally friendly and high-throughput method was developed for the determination of estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2) and estriol (E3) in human urine by liquid chromatography-fluorescence detector (HPLC-FLD). A biosorbent (bract) was proposed as extraction phase for Thin-Film SPME combined with 96-well system. The characterization of the biosorbent was performed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optimizations were carried out through univariate and multivariate approaches with optimal conditions comprised of urine samples diluted 40-fold, liquid desorption performed in methanol and addition of 20% (w/v) of NaCl in the sample. Considering an extraction/desorption cycle using the 96-well plate system, the sample preparation time was 1.7 min per sample, which contributes to the high-throughput of the method proposed. The analytical parameters of merit were determined and satisfactory results were achieved, including limits of detection ranging from 0.3 μg L^-1 for estradiol to 3 μg L^-1 for estrone, while limits of quantification varied from 1 μg L^-1 for estradiol to 10 μg L^-1 for estrone. The correlation coefficients ranged from 0.9947 for estrone to 0.9999 for estriol. The accuracy and intra-assay and intermediate precisions (RSD) were evaluated through extractions in diluted urine samples (40-fold) spiked with each analyte (1, 200 and 400 μg L^-1 for E3; 0.1, 200 and 400 μg L^-1 for E2; 0.5, 200 and 400 μg L^-1 for EE2 and 10, 200 and 400 μg L^-1 for E1). The relative recoveries (n = 3) ranged from 71 to 105%, intra-assay precision (n = 3) varied from 1 to 17% and intermediate precision (n = 9) ranged from 2 to 19%. The method developed can be successfully used for the quantification of estrogens in human urine samples.

Reproductive drugs and environmental contamination: quantum, impact assessment and control strategies

Industrial and municipal solid wastes, noise, pesticides, fertilizers and vehicular emission are visible pollutants responsible for environmental contamination and ill-effects on health of all living systems. But, environmental contamination due to drugs or medicines used for different purposes in humans and animals goes unseen largely and can affect the health of living system severely. During the last few decades, the usage of drugs has increased drastically, resulting in increased drug load in soil and water. Contraceptive and fertility drugs are extensively and effectively used in humans as well as animals for different purposes. Usage of these reproductive drugs in humans is increased manifold to manage reproductive problems and/or for birth control with changing lifestyles. These drugs are excreted in urine and faeces as metabolite or conjugated forms, leading to contamination of water, milk and animal produce, which are consumed directly by humans as well as animals. These drugs are not eliminated even by water treatment plant. Consumption of such contaminated water, milk, meat and poultry products results in reproductive disorders such as fertility loss in men and increase risk of different types of cancers in humans. Therefore, assessment of impact of environmental contamination by these drugs on living system is of paramount importance. The purpose of this review article is to provide a comprehensive analysis of various research and review reports on different contraceptive and fertility drugs used in human and animals, their occurrence in the environment and their ill-effects on living systems. The approaches to control this invisible menace have also been proposed.

A bioinspired polydopamine approach toward the preparation of gold-modified magnetic nanoparticles for the magnetic solid-phase extraction of steroids in multiple samples

In this work, a simple, facile, and sensitive magnetic solid-phase extraction method was developed for the extraction and enrichment of three representative steroid hormones before high-performance liquid chromatography analysis. Gold-modified Fe₃ O₄ nanoparticles, as novel magnetic adsorbents, were prepared by a rapid and environmentally friendly procedure in which polydopamine served as the reductant as well as the stabilizer for the gold nanoparticles, thus successfully avoiding the use of some toxic reagents. To obtain maximum extraction efficiency, several significant factors affecting the preconcentration steps, including the amount of adsorbent, extraction time, pH of the sample solution, and the desorption conditions, were optimized, and the enrichment factors for three steroids were all higher than 90. The validity of the established method was evaluated and good analytical characteristics were obtained. A wide linearity range (0.8-500 μg/L for all the analytes) was attained with good correlation (R²  ≥ 0.991). The low limits of detection were 0.20-0.25 μg/L, and the relative standard deviations ranged from 0.83 to 4.63%, demonstrating a good precision. The proposed method was also successfully applied to the extraction and analysis of steroids in urine, milk, and water samples with satisfactory results, which showed its reliability and feasibility in real sample analysis.

Bisphenol A concentrations in human urine, human intakes across six continents, and annual trends of average intakes in adult and child populations worldwide: A thorough literature review

Bisphenol A (BPA) is an important industrial raw material that is widely applied in daily products. BPA is also an endocrine-disrupting chemical that may adversely affect humans. This review thoroughly collected data on BPA concentration in human urine and determined main influencing factors. The average BPA intake of humans across six continents or the average value worldwide was calculated based on a simple model. Results showed that the average BPA intake was ranked from high to low as follows: Oceania, Asia, Europe, and North America in the child population and Oceania, Europe, Asia, and North America in the adult population. The annual trend of the average BPA intake was similar between the adult and child populations. The BPA intake in the two populations evidently decreased from 2000 to 2008 and then slightly increased from 2008 to 2011. The BPA intake in the child population started to decrease again from 2011, whereas the corresponding intake in the adult population continued to increase. The distinct difference likely contributed to the wide prohibition of the use of BPA in food-related products for children in many countries since 2009; the bans effectively decreased the total BPA exposure in the child population.

Extraction and detection of bisphenol A in human serum and urine by aptamer-functionalized magnetic nanoparticles

A new type of magnetic nanoparticles (MNPs), as the absorbents of bisphenol A (BPA), was prepared by functionalization of Fe₃O₄@SiO₂ with BPA-specific aptamer in this work. ssDNA aptamer was immobilized on the Fe₃O₄@SiO₂ surface through biotin-avidin interactions, playing a role of the specific probe for BPA. The resultant materials (Apt-MNPs) exhibited outstanding magnetic responsibility and can be separated efficiently by the magnetic field. Experimental results also showed that Apt-MNPs had large adsorption capacity and high competitive selectivity for the targeted compound BPA. Furthermore, Apt-MNPs were adopted as the specific absorbents to extract and enrich BPA from human serum and urine samples. Therefore, an efficient detection method of BPA was developed in combination with high-performance liquid chromatography (HPLC). The linearity of the method was over a range of 5-10,000 ng mL^-1 with a correlation coefficient of 0.99997, and the limit of detections (LODs) for serum and urine were 2.0 and 1.0 ng mL^-1, respectively. The recoveries of BPA in the spiked human serum and urine samples were 90.8 ± 7.3% (RSD) and 92.3 ± 1.5%, respectively. Our results demonstrated that Apt-MNPs were high-performance adsorbents for extracting and enriching BPA, resulting in fast and efficient detection of BPA in serum and urine samples. Graphical abstract Aptamer-MNPs were effective for BPA separation from serum and urine.

Bisphenol A disrupts steroidogenesis and induces a sex hormone imbalance through c-Jun phosphorylation in Leydig cells

Bisphenol A (BPA) is a well-known endocrine disrupting chemical (EDC) that is used to manufacture plastic consumer products. It is well known that exposure to BPA can induce defects in gonad development and negatively influences reproductive function in both males and females. In this study, we assessed the effects of BPA on hormone production in Leydig cells, which secrete hormones in the testes and support male fertility. We examined two steroidogenic enzymes, CYP11A1 and CYP19 that involved in sex hormone synthesis in mouse MA-10 Leydig cells. We found that BPA activated CYP gene in both mRNA and protein levels then resulted in alteration of the normal sex hormone ratio. Furthermore, we found that BPA induced c-Jun phosphorylation and contributed to CYP gene expression. Similar results were observed in an animal study. In conclusion, BPA disrupts the hormone environment in testis via steroidogenic gene activation through the JNK/c-Jun signaling pathway.

Silica nanoparticles–nylon 6 composites: synthesis, characterization and potential use as sorbent

Silica nanoparticle–nylon 6 composites are successfully synthesized following a simple and rapid procedure. After their characterization, the composites were evaluated as sorbents under a dispersive solid phase microextraction format.

Analytical methods for the endocrine disruptor compounds determination in environmental water samples

The potential risk of exposure to different xenobiotics, which can modulate the endocrine system and represent a treat for the wellness of an increasing number of people, has recently drawn the attention of international environmental and health agencies. Several agents, characterized by structural diversity, may interfer with the normal endocrine functions that regulate cell growth, homeostasis and development. Substances such as pesticides, herbicides, plasticizers, metals, etc. having endocrine activity (EDCs) are used in agriculture and industry and are also used as drugs for humans and animals. A difficulty in the analytical determination of these substances is the complexity of the matrix in which they are present. In fact, the samples most frequently analyzed consist of groundwater and surface water, including influent and effluent of wastewater treatment plants and drinking water. In this review, several sample pretreatment protocols, assays and different instrumental techniques recently used in the EDCs determination have been considered. This review concludes with a paragraph in which the most recent hyphenated-instrument techniques are treated, highlighting their sensitivity and selectivity for the analyses of environmental water samples.

LC-MS/MS signal enhancement for estrogenic hormones in water samples using experimental design

Present paper describes the optimization of LC-MS/MS conditions by using experimental design for selective and sensitive determination of estrogenic hormones namely estradiol (E2), estrone (E1), estriol (E3) and ethinyl estradiol (EE2).

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.

The association between nonylphenols and sexual hormones levels among pregnant women: a cohort study in Taiwan

Background

Nonylphenol (NP) has been proven as an endocrine disrupter and had the ability to interfere with the endocrine system. Though the health effects of NP on pregnant women and their fetuses are sustained, these negative associations related to the mechanisms of regulation for estrogen during pregnancy need to be further clarified. The objective of this study is to explore the association between maternal NP and hormonal levels, such as estradiol, testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH), and progesterone.

Methods

A pregnant women cohort was established in North Taiwan between March and December 2010. Maternal urine and blood samples from the first, second, and third trimesters of gestation were collected. Urinary NP concentration was measured by high-performance liquid chromatography coupled with fluorescent detection. A mixed-effects model using a generalised estimating equation (GEE) was applied to assess the associations between maternal NP concentration and plasma hormones throughout the three trimesters.

Results

In total, 162 singleton pregnant women completed this study through delivery. The geometric mean of creatinine-adjusted urinary NP concentrations were 4.27, 4.21, and 4.10 µg/g cre. in the first, second, and third trimesters respectively. A natural log-transformation of urinary NP concentrations were significantly associated with LH in the GEE model (β = −0.23 mIU/ml, p<0.01).

Conclusion

This perspective cohort study demonstrates that negative association occurs between maternal NP exposure and plasma LH levels. The estrogen-mimic effect of NP might influence the negative feedback on LH during pregnancy.

Analysis of estrogens and estrogen mimics in edible matrices--a review

This review provides a brief survey of the biological effects of selected endocrine-disrupting compounds that are formed after internal exposure of organisms. Further, the present analytical methods available for the determination of these compounds in foodstuffs are critically evaluated. The attention is primarily devoted to the methods for sample pretreatment, which are the main source of errors and are usually the most time-consuming step of the whole analysis. This review is focused on selected natural and synthetic estrogens, estrogen conjugates, and chemical additives used in the plastic industry that can act as estrogen mimics.

Occurrence and removal of free and conjugated estrogens in wastewater and sludge in five sewage treatment plants

The occurrence and fate of free and conjugated estrogens were investigated in wastewater and sludge from five sewage treatment plants (STPs) in Guangdong Province, China. Estrone (E1) and 17β-estradiol (E2) were found in all influent samples at concentrations of 69.3-280 ng L(-1) and 1.3-30 ng L(-1), respectively. The concentrations of conjugated estrogens were from ND (not detected) to 7.6 ng L(-1). High concentrations (27.6-235 ng g(-1)) of E1 were found in sludge of some STPs indicating that sorption was an important estrogen removal mechanism. According to the mass flux analyses for estrogens in STP-A, E2 was mainly removed in the anaerobic process and E1 removal was the combined efforts of biodegradation and sorption. Abnormally high concentrations of EE2 (42.6-246 ng L(-1)), detected with gas chromatography-mass spectrometry, were found in all influent samples of the STPs, therefore interlaboratory analysis with liquid chromatography-tandem mass spectrometry was conducted for confirmation, which detected no EE2 at all. In consideration of the rather lower estimated EE2 concentration than the measured value, it was speculated that the presence of interfering substances like tetracosanic acid in the matrix could lead to overestimation of EE2 concentration. Overall, the effluents still pose potential estrogenic effect to the downstream aquatic organisms.

Measurement of phenolic environmental estrogens in women with uterine leiomyoma

Objectives

To investigate the effect of phenolic environmental estrogens on uterine leiomyoma from the perspective of clinical epidemiology.

Methods

Urine and blood samples were collected from Han women with uterine leiomyoma and women without uterine leiomyoma, living in Nanjing, China, between September 2011 and February 2013. A total of 156 urine samples and 214 blood samples were collected from the uterine leiomyoma group and 106 urine samples and 126 blood plasma samples from the control group. Bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP) concentrations were determined by solid-phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

Results

Phenolic environmental estrogens in the uterine leiomyoma and control groups were compared based on: gravida>3 and gravida ≤ 3. In participants with gravida>3, urine OP concentration was significantly (P<0.05) higher in the uterine leiomyoma group than in the control group. In participants with gravida ≤ 3, urine NP concentration was significantly (P<0.05) higher in the uterine leiomyoma group compared to controls. Despite obstetric history, urine BPA mean exposure concentration was significantly (P<0.05) different between uterine leiomyoma group and control group. The urine BPA concentration was not significantly (P>0.05) different between gravida>3 and gravida ≤ 3 patients. There was no significant (P>0.05) difference in plasma concentrations of BPA, OP and NP between the leiomyoma group and control group. Mean exposure concentration and range of distribution of BPA, OP and NP plasma concentration differed between the uterine leiomyoma and control group.

Conclusion

Exposure level of phenolic environmental estrogens in human was related with leiomyoma tumorigenesis.

Neonatal outcomes of intrauterine nonylphenol exposure--a longitudinal cohort study in Taiwan

BACKGROUND

Nonylphenol (NP) is an environmental hormone with proven estrogenic effects. Although its adverse effects on animals are well documented, the effects of NP exposure on humans remain unclear, and those on the human foetus are completely unknown. This study explores the effects of intrauterine NP exposure on neonates.

METHODS

A cohort of pregnant women was established in a medical centre in northern Taiwan. Urine samples from the first, second, and third trimesters of gestation were collected. Urinary NP concentration was measured by high-performance liquid chromatography coupled with fluorescent detection. Neonatal outcomes were evaluated immediately after delivery. A mixed-effects model using a generalised estimating equation was applied to assess the association between gestational age, maternal body weight, and maternal NP concentration throughout the three trimesters. A multivariable regression model was used to determine the association between maternal NP level in urine in each trimester and neonatal outcomes.

RESULTS

In total, 162 singleton pregnant women completed this study through delivery. The geometric mean of creatinine-adjusted urinary NP concentrations were 4.27 μg/g, 4.21 μg/g, and 4.10 μg/g in the first, second, and third trimesters, respectively. Pregnant women whose urinary NP concentrations were above the median in the second trimester had low maternal weight gain (β=-1.55 kg, p=0.02) and short neonatal body length (β=-0.47 cm, p=0.04). Women with an above-median urinary NP concentration had an odds ratio of having a small for gestational age (SGA) neonate of 7.81 (p<0.05).

CONCLUSIONS

This study indicates that maternal high NP exposure in the second trimester is associated with SGA, decreased foetal body length at birth, and low maternal weight gain. The effects of this endocrine-disrupting substance on pregnant women and foetuses should be a concern during gestation.

4-Nonylphenol, bisphenol-A and triclosan levels in human urine of children and students in China, and the effects of drinking these bottled materials on the levels

4-Nonylphenol (4-NP), bisphenol-A (BPA) and triclosan (TCS) are three industrial chemicals used widely in daily products. This study investigated 4-NP, BPA and TCS levels in urine samples of 287 children and students aged from 3 to 24 years old in Guangzhou, China. Total (free and conjugated) amounts of 4-NP, BPA and TCS in the urine samples were detected using gas chromatography-mass spectrometry with negative chemical ionization. The detection rates of 4-NP, BPA and TCS were 100%, 100% and 93% respectively, given the detection limits of 3.8, 0.5 and 0.9 ng/L respectively. Data for 4-NP, BPA and TCS were presented in both creatinine-adjusted (microgram per gram creatinine) and unadjusted (microgram per liter) urinary concentrations. The geometric mean (GM) concentrations of urinary 4-NP, BPA and TCS were 15.92 μg/g creatinine (17.40 μg/L), 2.75 μg/g creatinine (3.00 μg/L) and 3.55 μg/g creatinine (3.77 μg/L) respectively. Multiple regression models considering age, gender, preferred drinking bottle and log-transformed creatinine were used to calculate the adjusted least square geometric mean (LSGM). Among these subjects, the females had higher LSGM concentrations of 4-NP, BPA and TCS than the males; and the only statistically significant difference was found for the LSGM concentrations of triclosan (p=0.031). Participants who reported to use ceramic cups more frequently had significantly lower LSGM concentrations of BPA than those who used plastic cups (p=0.037). Meanwhile, a three-week test of using polycarbonate bottles and ceramic cups to drink bottled water and boiled tap-water was carried out among 12 graduate students of 25 years old. The GM concentrations of urinary BPA at the end of the first week after using ceramic cups to drink bottled water were 7.16 μg/g creatinine, then decreased significantly to 3.49 μg/g creatinine after the second week of using ceramic cups to drink boiled tap-water (p<0.05), and finally increased to 4.15 μg/g creatinine after the third week of using polycarbonate bottles in drinking boiled tap-water. The results indicate that in daily life the use of polycarbonate bottles or drinking of bottled water is likely to increase the ingestion of BPA, resulting in an increase in urinary BPA levels.

Radioassay-Based Approach to Investigate Fate and Transformation of Conjugated and Free Estrogens in an Agricultural Soil

Estrogens, a potent group of endocrine disruptors toward aquatic species, are primarily excreted as conjugates from humans and animals. Radioassay-based approaches with detailed speciation have been frequently conducted for environmental-fate studies for pesticides; however, such techniques have not been exploited for reproductive hormones, and especially for hormone conjugates. This article describes a simple, robust, and high-mass-recovery approach to investigate the fate and transformation of a prototype estrogen conjugate, that is, 17β-estradiol-3-glucuronide (E2-3G), and its metabolites (free estrogens) in a laboratory soil and water matrix without the need for enzymatic cleavage and/or fluorescent derivatization. E2-3G and its metabolites were baseline resolved in a single run using high-performance liquid chromatography (HPLC) and quantified by liquid scintillation counting of the HPLC effluents. Transformation of E2-3G and the disposition of its metabolites--the free estrogens 17β-estradiol and estrone--into aqueous, sorbed, and gaseous phases, were adequately accounted for in a soil-water batch system. High mass balances ranging from 99.0% to 114.1% were obtained. Although the method gave lower sensitivity (parts per billion) than tandem mass spectrometer (parts per trillion), it offered sufficient chromatographic resolution and sensitivity to study the fate of labile estrogens in environmental matrices, using the concentration range of this study. An additional advantage of the approach was the relatively low cost of the instrumentation employed. The presented approach can be successfully applied to study the fate of conjugated hormones and their metabolites in the environment allowing simultaneous discernment of complex fate and transformation processes in soil, water, and gas.

Removal of estrogens in municipal wastewater treatment plants: a Chinese perspective

Great efforts have been made in China to retrofit and upgrade the existing municipal wastewater treatment plants (WWTPs) for enhanced removal of organic substrates and in particular nutrients. However, the removal of trace recalcitrant or hazardous organic chemicals, e.g. steroid estrogens, one group of typical endocrine disrupting chemicals, has long been overlooked. The extensive investigations on estrogen removal rates in global and Chinese WWTPs and the estrogen biodegradation kinetics results in batch laboratory experiments are reviewed in this study. The effects of estrogen initial concentration and nitrifying activated sludge are highlighted. Challenges existing in current estrogen studies are pointed out, which are relevant for researches on fate and behavior of similar down-the-drain chemicals in both Chinese and global WWTPs.

Chemiluminescence of CdTe nanocrystals catalyzed by sodium hexametaphosphate and its sensitive application for determination of estrogens

A novel flow injection nanocrystals (NCs) chemiluminescence (CL) analysis method has been established for the determination of estradiol, estriol and estrone based on the enhancement of CdTe NCs-KMnO(4) CL reaction catalyzed by sodium hexametaphosphate. Glutathione (GSH)-capped CdTe nanocrystals were synthesized in aqueous medium, and the CdTe NCs emitted at around 555 nm was selected as the light emitter in CdTe NCs-KMnO(4) chemiluminescence (CL) system. It has been found that sodium hexametaphosphate (SHMP) enhanced the CL of the CdTe NCs-KMnO(4) system and estrogens increased these CL signals again in near neutral solution. UV-visible spectra, photoluminescence (PL) spectra, transmission electron microscopy (TEM) and CL spectra were used to characterize CdTe nanoparticles and investigate the mechanism of the CL reaction. On the basis of the enhancement, a novel flow-injection CL method has been established for the determination of estrogens. Under the optimum experimental conditions, three linear relationships were obtained. The method described is simple, sensitive, and has been successfully utilized for the determination of estrogens in tap water samples.

Urinary, Circulating, and Tissue Biomonitoring Studies Indicate Widespread Exposure to Bisphenol A

Bisphenol A (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Thus, there are concerns that the amount of BPA to which humans are exposed may cause adverse health effects. We examined many possibilities for why biomonitoring and toxicokinetic studies could come to seemingly conflicting conclusions. More than 80 published human biomonitoring studies that measured BPA concentrations in human tissues, urine, blood, and other fluids, along with two toxicokinetic studies of human BPA metabolism were examined. Unconjugated BPA was routinely detected in blood (in the nanograms per milliliter range), and conjugated BPA was routinely detected in the vast majority of urine samples (also in the nanograms per milliliter range). In stark contrast, toxicokinetic studies proposed that humans are not internally exposed to BPA. Available data from biomonitoring studies clearly indicate that the general population is exposed to BPA and is at risk from internal exposure to unconjugated BPA. The two toxicokinetic studies that suggested human BPA exposure is negligible have significant deficiencies, are directly contradicted by hypothesis-driven studies, and are therefore not reliable for risk assessment purposes.

Recent trends in biomonitoring of bisphenol A, 4-t-octylphenol, and 4-nonylphenol

Bisphenol A (BPA), 4-t-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) are man-made alkylphenolic environmental contaminants possessing controversial endocrine disruption properties. Nowadays, an increased interest is raised for their accurate determination in biological media in order to estimate the exposure to these compounds and the associated health risk. The aim of this review is to present the available analytical methodologies for biomonitoring these three EDCs in human population. In non-occupational human exposure, they are detected in human matrices in trace level concentrations, commonly lower than 1ng/mL. The use of mass spectrometry based methods is particularly emphasized due to their well known superiority over sensitivity, selectivity and precision, even in difficult matrices, such as blood plasma and serum. Recent and most applicable sample preparation techniques are thoroughly presented. The benefits of solid phase extraction (SPE) and expected developments are demonstrated. Recent results from exposure assessment and epidemiologic studies for BPA, 4-t-OP and 4-NP are summarized and future trends are discussed.

Urinary bisphenol A concentrations and their implications for human exposure in several Asian countries

Bisphenol A (BPA) is an industrial chemical used in the manufacture of polycarbonate plastics and epoxy resins. Due to the potential of this compound to disrupt normal endocrinal functions, concerns over human exposure to BPA have been raised. Although several studies have reported human exposure to BPA in Western nations, little is known about exposure in Asian countries. In this study, we determined total urinary BPA concentrations (free plus conjugated) in 296 urine samples (male/female: 153/143) collected from the general population in seven Asian countries, China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam, using high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). On the basis of urinary BPA concentrations, we estimated the total daily intake. The results indicated that BPA was detected in 94.3% of the samples analyzed, at concentrations ranging from <0.1 to 30.1 ng/mL. The geometric mean concentration of BPA for the entire sample set from seven countries was 1.20 ng/mL. The highest concentration of BPA was found in samples from Kuwait (median: 3.05 ng/mL, 2.45 μg/g creatinine), followed by Korea (2.17 ng/mL, 2.40 μg/g), India (1.71 ng/mL, 2.09 μg/g), Vietnam (1.18 ng/mL, 1.15 μg/g), China (1.10 ng/mL, 1.38 μg/g), Malaysia (1.06 ng/mL, 2.31 μg/g), and Japan (0.95 ng/mL, 0.58 μg/g). Among the five age groups studied (≤ 19, 20-29, 30-39, 40-49, and ≥ 50 years), the highest median concentration of BPA was found in urine samples from the age group of ≤ 19 years. There was no significant difference in BPA concentrations between genders (male and female) or domicile of residence (rural and urban). The estimated median daily intakes of BPA for the populations in Kuwait, Korea, India, China, Vietnam, Malaysia, and Japan were 5.19, 3.69, 2.90, 2.13, 2.01, 1.80, and 1.61 μg/day, respectively. The estimated daily intake of BPA in the seven Asian countries was significantly lower than the tolerable daily intake recommended by the U.S. Environmental Protection Agency. This is the first study to document the occurrence of and human exposure to BPA in several Asian countries.