Analytical determination of bisphenol A (BPA) and bisphenol analogues in paper products by GC-MS/MS

Per- and Polyfluoroalkyl Substances in Food Packaging: Migration, Toxicity, and Management Strategies

PFASs are linked to serious health and environmental concerns. Among their widespread applications, PFASs are known to be used in food packaging and directly contribute to human exposure. However, information about PFASs in food packaging is scattered. Therefore, we systematically map the evidence on PFASs detected in migrates and extracts of food contact materials and provide an overview of available hazard and biomonitoring data. Based on the FCCmigex database, 68 PFASs have been identified in various food contact materials, including paper, plastic, and coated metal, by targeted and untargeted analyses. 87% of these PFASs belong to the perfluorocarboxylic acids and fluorotelomer-based compounds. Trends in chain length demonstrate that long-chain perfluoroalkyl acids continue to be found, despite years of global efforts to reduce the use of these substances. We utilized ToxPi to illustrate that hazard data are available for only 57% of the PFASs that have been detected in food packaging. For those PFASs for which toxicity testing has been performed, many adverse outcomes have been reported. The data and knowledge gaps presented here support international proposals to restrict PFASs as a group, including their use in food contact materials, to protect human and environmental health.

Investigation of potential migratables from paper and board food contact materials

Since the ban on single-use plastic articles in Europe, the food contact material (FCM) industry has been forced to move to more sustainable alternatives. Paper and board FCM are convenient alternatives but must be safe for consumers. This study aims to investigate potential migrations of various substances (e.g., plasticizers, photoinitiators, primary aromatic amines, mineral oil, and bisphenols) from straws and takeaway articles made of paper and board. Twenty straws and fifty-eight takeaway articles were carefully selected and investigated using liquid and gas chromatography coupled with tandem mass spectrometry or flame ionization detector. Fourteen substances of all the targeted categories were found in takeaway articles, including seven plasticizers, two photoinitiators, one primary aromatic amine, two bisphenols, and the saturated and aromatic fraction of mineral oil (MOSH and MOAH, respectively). In straws, fewer substances were detected, i.e., six substances, including three plasticizers, one photoinitiator, MOSH, and MOAH. At least one of the target substances was detected in 88% of the samples, demonstrating the importance of further evaluation of these materials. Finally, the associated risks were assessed, highlighting the potential risks for several types of articles regarding bisphenol A, one primary aromatic amine (3.3-DMB), and MOSH and MOAH.

The Nature of the Spark Is a Pivotal Element in the Design of a Miller-Urey Experiment

Miller and Urey applied electric sparks to a reducive mixture of CH4, NH3, and water to obtain a complex organic mixture including biomolecules. In this study, we examined the impact of temperature, initial pressure, ammonia concentration, and the spark generator on the chemical profile of a Miller-Urey-type prebiotic broth. We analyzed the broth composition using Gas Chromatography combined with Mass Spectroscopy (GC/MS). The results point towards strong compositional changes with the nature of the spark. Ammonia exhibited catalytic properties even with non-nitrogen-containing compounds. A more elevated temperature led to a higher variety of substances. We conclude that to reproduce such a broth as well as possible, all the studied parameters need to be tightly controlled, the most difficult and important being spark generation.

Simultaneous Quantification of 16 Bisphenol Analogues in Food Matrices

Exposure to bisphenol analogues can occur in several ways throughout the food production chain, with their presence at higher concentrations representing a risk to human health. This study aimed to develop effective analytical methods to simultaneously quantify BPA and fifteen bisphenol analogues (i.e., bisphenol AF, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, bisphenol TMC, and tetramethyl bisphenol F) present in canned foods and beverages. Samples of foods and beverages available in the Swiss and EU markets (n = 22), including canned pineapples, ravioli, and beer, were prepared and analyzed using QuEChERS GC-MS. The quantification method was compared to a QuEChERS LC-MS/MS analysis. This allowed for the selective and efficient simultaneous quantitative analysis of bisphenol analogues. Quantities of these analogues were present in 20 of the 22 samples tested, with the most frequent analytes at higher concentrations: BPA and BPS were discovered in 78% and 48% of cases, respectively. The study demonstrates the robustness of QuEChERS GC-MS for determining low quantities of bisphenol analogues in canned foods. However, further studies are necessary to achieve full knowledge of the extent of bisphenol contamination in the food production chain and its associated toxicity.

Bisphenol A Imprinted Electrochemical Sensor Based on Graphene Quantum Dots with Boron Functionalized g-C3N4 in Food Samples

A molecular imprinted electrochemical sensor based on boron-functionalized graphitic carbon nitride (B-g-C₃N₄) and graphene quantum dots (GQDs) was presented for selective determination of bisphenol A (BPA). In particular, by combining the selectivity and high stability properties, which are the most important advantages of molecular imprinted polymers, and the highly sensitive properties of GQDs/B-g-C₃N₄ nanocomposite, a highly selective and sensitive analytical method was developed for BPA analysis. Firstly, GQDs/B-g-C₃N₄ nanocomposite was characterized by using microscopic, spectroscopic, and electrochemical techniques. This novel molecular imprinted electrochemical sensor for BPA detection demonstrated a linearity of 1.0 × 10^-11-1.0 × 10^-9 M and a low detection limit (LOD, 3.0 × 10^-12 M). BPA-imprinted polymer on GQDs/B-g-C₃N₄ nanocomposite also showed good stability, repeatability and selectivity in food samples.

Bisphenol A monitoring during anaerobic degradation of papers with thermochromic prints in soil

Pseudoestrogene bisphenol A (BPA) can be important ingredient of thermochromic inks, increasingly used materials in thermal printing paper, security printing, advertising, design and as temperature indicators in medicine and food industry. BPA mass fraction in thermochromic inks can be up to several percent. Hence, disposal of items with thermochromic prints pose a risk of environmental pollution. In this work BPA mass fraction was monitored during anaerobic degradation of papers with thermochromic prints in soil in both matrices: papers and soil. The degradation conditions simulated deeper layers of waste at a landfill site. Six types of papers with prints of thermochromic ink containing 2% of BPA were subjected to anaerobic degradation over up to 150 days. Initial mass fractions of BPA in papers decreased form (126-460) μg/g to (<QL - 45) μg/g after 150 days. BPA amounts were reduced 10 to 50 times depending on the paper type: least for synthetic paper and most for wood-free coated. For soil analysis new HPLC-UV method was developed and validated. The method was linear from 0.75 ng/g to 0.6 μg/g of BPA in soil with correlation coefficient of 0.9994. Method precision was 4.4%, accuracy 83% and detection limit 0.9 ng/g. Expectedly, amount of BPA in soil was increasing during the experiment. Mass fractions of BPA in soil were from not detected in earlier stage of degradation to (4.9-23.2) ng/g after 150 days. Final BPA amounts in soil were similar to those found in industrial, urban and agricultural soils worldwide. Hence, BPA from papers with thermochromic prints was notably decomposed, and contaminated soil had the capacity to absorb and decompose BPA even under anaerobic conditions. After 150 days of anaerobic degradation, only up to 1.86% of BPA contained in paper prints was found in soil, whilst, on average, 4% of initial BPA remained in paper.

Endocrine modulating chemicals in food packaging: A review of phthalates and bisphenols

Phthalates and bisphenol chemicals have been widely used globally in packaging materials and consumer products for several decades. These highly functional chemicals have become a concern due to their toxicity (i.e., endocrine/hormone modulators) and ability to migrate from food contact materials (FCMs) into food matrices and the environment resulting in human and environmental health risks. FCMs, composed of postconsumer materials, are particularly high risk for containing these compounds. The evaluation of postconsumer recycled feedstocks in FCMs is compulsory and selection of an appropriate detection method to comply with applicable regulations is necessary to evaluate human and environmental safety. Numerous regulations have been proposed and passed globally for both compound classes that are recognized as priority pollutants by the United States Environmental Protection Agency and the European Union. Several brand owners and retailers have also released their own "restricted substance lists" due to the mounting consumer and regulatory concerns. This review article has two goals: (1) discuss the utilization, toxicology, human exposure routes, and occurrence levels of phthalates and bisphenols in FCMs and associated legislation in various countries and (2) discuss critical understanding and updates for detection/quantification techniques. Current techniques discussed include extraction and sample preparation methods (solid-phase microextraction [SPME], headspace SPME, Soxhlet procedure, ultrasound-assisted extraction), chromatographic techniques (gas, liquid, detectors), and environmental/blank considerations for quantification. This review complements a previous review of phthalates in foods from 2009 by discussing phthalate and bisphenol characteristics, analytical methods of determining concentrations in packaging materials, and their influence on the migration potential into food.

Bisphenols S and F drive ovarian granulosa cell tumor invasion via a metabolic switch

Alterations in the metabolism of cancer cells are crucial for tumor growth and progression. However, the mechanism whereby environmental pollutants such as bisphenols F (BPF) and S (BPS) affect glucose metabolism through the glycolytic pathway, and therefore influence tumor progression, are unclear. Both bisphenols are endocrine-disrupting molecules that are used in plastics. As a consequence of their widespread use, these compounds have been detected in various human body fluids. Thus, hormone-sensitive cancers, such as ovarian cancers, are exposed to these compounds. In the present study, we aimed to determine the effects of the concentrations of BPS and BPF found in body fluids on the cell viability, glucose uptake, glycolysis, oxygen consumption, and invasion by the adult ovarian granulosa cell tumor (AGCT) cell line. We found that BPS and BPF increased the glucose uptake, hexokinase activity, proliferation, and invasion of the cells at environmentally relevant concentrations. Furthermore, we identified an inhibition of glycolysis in parallel with an increase in oxygen consumption, suggesting a BPS/BPF-induced switch from aerobic glycolysis to mitochondrial respiration. In summary, these findings demonstrate a new mechanism through which BPS and BPF promote ovarian granulosa cell tumor progression by increasing energy production through mitochondrial respiration. Thus, both bisphenols induced a metabolic switch that appears to be a stimulus for AGCT progression.

Association between urinary bisphenol analogue concentrations and lung cancer in adults: A case-control study

Elevated urinary bisphenol A (BPA) concentrations have been associated with lung cancer in humans. However, toxicological studies demonstrated that the proliferation of lung cancer cells was inhibited by BPA exposure. Therefore, it is still necessary to determine whether exposure to BPA and other bisphenol analogues (BPs) is associated with lung cancer in humans. In this study, 226 lung cancer patients and 243 controls were randomly recruited. Concentrations of three BPs in human urine were quantified and their relationships with the risk of human lung cancer were evaluated. BPA (mean 1.03 ng/mL, 0.87 μg/g Cre) was the predominant BP in human urine, followed by bisphenol S (BPS) (0.72 ng/mL, 0.53 μg/g Cre) and bisphenol F (0.32 ng/mL, 0.37 μg/g Cre). Significant correlations between creatinine-corrected urinary BPA concentrations and the lung cancer risk (odds ratio (OR) _adjusted = 1.28, 95% confidence interval (CI): 1.17, 1.40; P_trend = 0.04) were found using logistical regression analysis. Creatinine-corrected urinary concentrations of BPS in participants showed significant correlations with lung cancer (OR_adjusted = 1.23, 95% CI: 1.04, 1.59; P_trend = 0.01) in the adjusted model. In the stratification analysis, the significant correlation between urinary creatinine-corrected concentrations of BPA and the risk of lung cancer still observed in male participants (OR = 1.36, 95% CI: 1.09, 1.62, p = 0.040). This study demonstrates that elevated human exposure to BPA and BPS may be associated with the increased lung cancer risk.

Three-dimensional flower-like SnS2 materials for dispersive solid-phase extraction of endocrine-disrupting phenols

In this study, three-dimensional flower-like tin disulfide materials were prepared, and a highly efficient dispersive solid-phase extraction method was developed using the obtained three-dimensional tin disulfide adsorbents for the preconcentration and determination of six endocrine-disrupting phenols in combination with high-performance liquid chromatography-ultraviolet detection. Several important experimental parameters influencing extraction efficiency were investigated, including the amount of adsorbent, ultrasound time, sample solution pH, sample volume, type of elution solvent, desorption time, and the number of desorption times. Under the optimized experimental conditions, the developed method showed good linearity with the determination coefficients of 0.993-0.998 in the linear range of 0.5-400 ng/ml and low limits of detection in the range of 0.15-1.0 ng/ml, as well as satisfactory intra-day and inter-day precisions with relative standard deviations of 0.1-9.8%. Finally, the proposed method was successfully applied for the enrichment and determination of trace endocrine-disrupting phenols in milk, tea beverage, and plastic bottled water samples, and acceptable recoveries were obtained from 70.1% to 119.1% under four different spiked concentration levels. The results showed that the three-dimensional tin disulfide materials had great potential for the extraction of endocrine-disrupting phenols contaminants in environmental and food samples.

Non-permanent primary food packaging materials assessment: Identification, migration, toxicity, and consumption of substances

Almost all processed food comes packaged in either plastic, glass, metal, or paper and paperboard materials, and many packaging materials are disposed of after a single use (linear economy). Based on the concept of a circular economy, the recycling of food packaging materials has become one of the main targets for industries and regulators around the world. However, recycling presents particular challenges, mainly related to the recycled material composition, which determines its reusability, application, functionality, and chemical safety. In this latter matter, it has been demonstrated that the use of recycled food packaging materials increases the number and possible sources of substances that could be present in the packaging material, which is of concern as substances that can migrate into food and cause health hazards upon consumption. This review compiles information regarding substances detected in non-permanent food packaging materials, focusing mainly on plastics, paper, and paperboards. The compilation of literature studies (110 research articles) on the presence of intentionally added substances (IAS) and non-intentionally added substances (NIAS) in food packaging materials, their migration, toxicity, and dietary exposure has been summarized, evaluated, and discussed. In addition, current sustainable food packaging trends have been mentioned. Finally, approaches to reduce the presence, migration, and potential exposure to substances that have migrated from packaging materials into food have been reviewed.

USAEME-GC/MS Method for Easy and Sensitive Determination of Nine Bisphenol Analogues in Water and Wastewater

A new, simple and sensitive method for isolating nine compounds from the bisphenol group (analogues: A, B, C, E, F, G, Cl₂, Z, AP) based on one-step liquid-liquid microextraction with in situ acylation followed by gas chromatography-mass spectrometry was developed and validated using influent and effluent wastewaters. The chemometric approach based on the Taguchi method was used to optimize the main conditions of simultaneous extraction and derivatization. The recoveries of the proposed procedure ranged from 85 to 122%, and the repeatability expressed by the coefficient of variation did not exceed 8%. The method's limits of detection were in the range of 0.4-64 ng/L, and the method's limits of quantification ranged from 1.3 to 194 ng/L. The developed method was used to determine the presence of the tested compounds in wastewater from a municipal wastewater treatment plant located in northeastern Poland. From this sample, eight analytes were detected. Concentrations of bisphenol A of 400 ng/L in influent and 100 ng/L in effluent were recorded, whereas other bisphenols reached 67 and 50 ng/L for influent and effluent, respectively. The removal efficiency of bisphenol analogues in the tested wastewater treatment plant ranged from 7 to approximately 88%.

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

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

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.

Metabolomic Studies for the Evaluation of Toxicity Induced by Environmental Toxicants on Model Organisms

Environmental pollution causes significant toxicity to ecosystems. Thus, acquiring a deeper understanding of the concentration of environmental pollutants in ecosystems and, clarifying their potential toxicities is of great significance. Environmental metabolomics is a powerful technique in investigating the effects of pollutants on living organisms in the environment. In this review, we cover the different aspects of the environmental metabolomics approach, which allows the acquisition of reliable data. A step-by-step procedure from sample preparation to data interpretation is also discussed. Additionally, other factors, including model organisms and various types of emerging environmental toxicants are discussed. Moreover, we cover the considerations for successful environmental metabolomics as well as the identification of toxic effects based on data interpretation in combination with phenotype assays. Finally, the effects induced by various types of environmental toxicants in model organisms based on the application of environmental metabolomics are also discussed.

Determination of Free Bisphenol A in Commercially Packaged Ready-to-Consume Carbonated/Non-Carbonated and Non-Alcoholic Beverages with Immunoaffinity Column Purification and UPLC with Fluorescence Detector, First Action 2019.07

BACKGROUND

Bisphenol A (BPA) is a chemical of concern in the food industry. There is a need for a sensitive analytical method for the determination of BPA in beverages.

OBJECTIVE

To develop a method for the determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks.

METHOD

Replicates of a carbonated soft drink, orange juice with pulp, and a dairy-based coffee drink at spiking levels ranging from 0 to 32 ng/mL were analyzed. The carbonated soft drink was adjusted to pH 7.4 and diluted with phosphate buffered saline (PBS). The orange juice with pulp and the dairy-based coffee drink were extracted with methanol and sodium chloride, then diluted with PBS.

RESULTS

LOD ranged from 0.06 to 0.08 ng/mL and LOQ ranged from 0.10 to 0.14 ng/mL. Recoveries of BPA from all sample types at 1 to 16 ng/mL spiked levels were between 93 and 100%; relative standard deviation (RSDr, %) ranged from 0.71 to 8.38% depending on matrix and spiking levels.

CONCLUSIONS

The results indicate that the method for determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks is reproducible and meets AOAC Official MethodSM performance criteria.

HIGHLIGHTS

The test portions were filtered and the filtrates applied to an immunoaffinity column (IAC) containing antibodies specific for BPA. After the column was washed with water, BPA was eluted from the IAC with 80% methanol and the eluate was directly injected, or concentrated and injected, into ultra-performance liquid chromatography (UPLC) with fluorescence detector (FLD) for separation, detection, and quantitation.

Evaluation of the effects of low nanomolar bisphenol A-like compounds' levels on early human embryonic development and lipid metabolism with human embryonic stem cell in vitro differentiation models

The widely used chemical bisphenol A (BPA) has been associated with several health effects. In recent years, many derivatives were developed to replace BPA although without thorough toxicological evaluation. Here, we employed a human embryoid body (EB)-based in vitro global differentiation and hepatic specification models, followed by RNA-seq analyses, to comprehensively study the potential developmental toxicity of six BPA replacements (BPS, BPF, BPZ, BPB, BPE, and BPAF), as compared to BPA. We found that those bisphenols may disrupt lineage commitment and lipid metabolism during early embryonic development. These effects mostly manifested via the dysregulation of HOX and APO family genes. Moreover, among the seven bisphenols analyzed, BPE seemed to have the mildest effects.

The presence of bisphenol A in the thermal paper in the face of changing European regulations - A comparative global research

Bisphenol A (BPA) is used as a color developer in a thermal paper that after a heating process reacts with a leuco dye and changes it to a colored form. Receipts from cash registers are considered as the main source of consumer exposure to bisphenols together with polycarbonates and epoxy resins. Levels of BPA and its possible alternatives were determined in thermal paper samples collected between May 2018 and May 2019 in 22 European and 17 non-European countries on all inhabited continents (220 samples in total, 133 of which were from Europe and 87 from other countries). These measurements were intended to check the level of BPA presence in receipts originating from different countries, especially from Europe in the light of changing regulations restricting its use. The effect of thermal printing on developer content was also analyzed, but no major changes in concentrations of bisphenols were observed during the process. Thus, printed receipts could be used for the determination of bisphenol content. Analysis of receipts from 39 countries has shown that BPA is still the most common compound used around the world with 69% samples containing this color developer. Among other tested bisphenols, BPS was used as a color developer in 20% samples, but it was noted that all samples collected from Japan and the United States of America were found to contain only BPS. Other bisphenols (F, AF, E, and B) considered as possible alternatives for BPA were detected only at trace levels or not detected at all, which showed that they were not used as color developers. The relatively large use of BPS as a BPA substitute is worrying because this compound not only has similar endocrine properties but is also poorly biodegradable. Besides, its relatively high polarity facilitates spreading in the environment.

Prenatal Exposure to Bisphenol A, E, and S Induces Transgenerational Effects on Male Reproductive Functions in Mice

This study was performed to examine the transgenerational effects of bisphenol (BP) A analogs, BPE, and BPS on male reproductive functions using mice as a model. CD-1 mice (F0) were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5 or 50 µg/kg/day) from gestational day 7 (the presence of vaginal plug = 1) to birth. Mice from F1 and F2 offspring were used to generate F3 males. Prenatal exposure to BPA, BPE, and BPS decreased sperm counts and/or motility and disrupted the progression of germ cell development as morphometric analyses exhibited an abnormal distribution of the stages of spermatogenesis in F3 males. Dysregulated serum levels of estradiol-17β and testosterone, as well as expression of steroidogenic enzymes in F3 adult testis were also observed. In the neonatal testis, although apoptosis and DNA damage were not affected, mRNA levels of DNA methyltransferases, histone methyltransferases, and their associated factors were increased by BP exposure. Furthermore, BP exposure induced immunoreactive expression of DNMT3A in Sertoli cells, strengthened DNMT3B, and weakened H3K9me2 and H3K9me3 in germ cells of the neonatal testis, whereas DNMT1, H3K4me3, and H3K27ac were not affected. In adult testis, stage-specific DNMT3B was altered by BP exposure, although DNMT3A, H3K9me2, and H3K9me3 expression remained stable. These results suggest that prenatal exposure to BPA, BPE, and BPS induces transgenerational effects on male reproductive functions probably due to altered epigenetic modification following disruption of DNMTs and histone marks in the neonatal and/or adult testis.

Prenatal Exposure to Bisphenol A Analogues on Female Reproductive Functions in Mice

This study was performed to examine whether prenatal exposure to bisphenol (BP) A analogues, BPE and BPS, negatively impacts female reproductive functions and follicular development using mice as a model. CD-1 mice were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5, 20, or 50 µg/kg/day) from gestational day 11 (the presence of vaginal plug = 1) to birth. Exposure to BPA, BPE, and BPS accelerated the onset of puberty and exhibited abnormal estrous cyclicity, especially with lower doses. Females exposed to BPA, BPE, and BPS exhibited mating difficulties starting at 6 months of age. By 9 months, mice exhibited various fertility problems including reduced pregnancy rate, parturition issues, and increased dead pups at birth. Furthermore, the levels of serum testosterone were elevated by BPE or BPS exposure at the age of 9 months, whereas estrogen levels were not affected. On the other hand, the dysregulated expression of steroidogenic enzymes was observed in the ovary at 3, 6, or 9 months of age by BPE or BPS exposure. When we examined neonatal ovary on postnatal day 4, BPA, BPE, and BPS exposure inhibited germ cell nest breakdown and reduced number of primary and secondary follicles. These results suggest that prenatal exposure to BPA analogues, BPE, and BPS, have effects on fertility in later reproductive life probably due to the disruption of early folliculogenesis.

Determination of endocrine disruptive phenolic compounds by gas chromatography mass spectrometry after multivariate optimization of switchable liquid-liquid microextraction and assessment of green profile

This study presents an accurate method for the determination of alkyl phenols and bisphenol A at trace levels using gas chromatography mass spectrometry after preconcentration with switchable liquid-liquid microextraction. In order to achieve high extraction output, the environmentally friendly switchable liquid-liquid microextraction method was optimized by varying parameters such as amount of switchable solvent, sodium hydroxide concentration/amount and the mixing period in a Box-Behnken experimental design. Under optimum extraction conditions, the limits of detection calculated for the analytes were between 0.13 and 0.54 ng/mL. The analytes showed good linearity over broad calibration ranges, and low percent relative standard deviations established good precision. Spiked recovery studies were performed on municipal wastewater and tap water to determine the method's suitability and accuracy, and the results (87-106%) obtained were satisfactory. Bisphenol A was detected (4.0-14 ng/mL) in four plastic samples investigated under high temperature conditions.

Prenatal Exposure to Bisphenol A, E, and S Induces Transgenerational Effects on Female Reproductive Functions in Mice

This study was performed to examine the transgenerational effects of bisphenol (BP) A analogs, BPE, and BPS on female reproductive functions using mice as a model. CD-1 mice (F0) were orally exposed to control treatment (corn oil), BPA, BPE, or BPS (0.5 or 50 µg/kg/day) from gestational day 7 (the presence of vaginal plug = 1) to birth. Mice from F1 and F2 offspring were used to generate F3 females. Prenatal exposure to BPA, BPE, and BPS accelerated the onset of puberty and exhibited abnormal estrous cyclicity in F3 females, and those females exhibited mating difficulties starting at 6 months of age. Various fertility problems including reduced pregnancy rates, parturition, and nursing issues were also observed starting at 6 months, which worsened at 9 months. The levels of serum estradiol-17β were elevated by BPA or BPS exposure at the age of 6 months, whereas testosterone levels were not affected. The dysregulated expression of steroidogenic enzymes was observed in the ovary at 3 or 6 months of age by BPE or BPS exposure. However, BPA, BPE, and BPS exposure did not affect neonatal follicular development such as germ cell nest breakdown or follicle numbers in the ovary on postnatal day 4. These results suggest that prenatal exposure to BPA analogs, BPE and BPS, have transgenerational effects on female reproductive functions in mice.

The BPA-substitute bisphenol S alters the transcription of genes related to endocrine, stress response and biotransformation pathways in the aquatic midge Chironomus riparius (Diptera, Chironomidae)

Bisphenol S (BPS) is an industrial alternative to the endocrine disruptor bisphenol A (BPA), and can be found in many products labeled “BPA-free”. Its use has grown in recent years, and presently it is considered a ubiquitous emerging pollutant. To date there is a lack of information on the effects of BPS on invertebrates, although they represent more than 95% of known species in the animal kingdom and are crucial for the structure and proper function of ecosystems. In this study, real-time RT-PCR was used to determine the early detrimental effects of BPS on the transcriptional rate of genes in the model species Chironomus riparius, specifically those related to the ecdysone pathway (EcR, ERR, E74, Vtg, cyp18a1) crucial for insect development and metamorphosis, stress and biotransformation mechanisms (hsp70, hsp40, cyp4g, GPx, GSTd3) that regulate adaptive responses and determine survival, and ribosome biogenesis (its2, rpL4, rpL13) which is essential for protein synthesis and homeostasis. While 24-hour exposure to 0.5, 5, 50, and 500 μg/L BPS had no effect on larval survival, almost all the studied genes were upregulated following a non-monotonic dose-response curve. Genes with the greatest increases in transcriptional activity (fold change relative to control) were EcR (3.8), ERR (2), E74 (2.4), cyp18a1 (2.5), hsp70 (1.7), hsp40 (2.5), cyp4g (6.4), GPx (1.8), and GST (2.1), while others including Vtg, GAPDH, and selected ribosomal genes remained stable. We also measured the transcriptional activity of these genes 24 hours after BPS withdrawal and a general downregulation compared to controls was observed, though not significant in most cases. Our findings showed that BPS exposure altered the transcriptional profile of these genes, which may have consequences for the hormone system and several metabolic pathways. Although further research is needed to elucidate its mode of action, these results raise new concerns about the safety of BPA alternatives.

Neuroendocrine disruption in animal models due to exposure to bisphenol A analogues

Animal and human studies provide evidence that exposure to the endocrine disrupting chemical (EDC), bisphenol A (BPA), can lead to neurobehavioral disorders. Consequently, there is an impetus to identify safer alternatives to BPA. Three bisphenol compounds proposed as potential safer alternatives to BPA are bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF). However, it is not clear whether these other compounds are safer in terms of inducing less endocrine disrupting effects in animals and humans who are now increasingly coming into contact with these BPA-substitutes. In the past few years, several animal studies have shown exposure to these other bisphenols induce similar neurobehavioral disruption as BPA. We will explore in this review article the current studies suggesting these other bisphenols result in neuroendocrine disruptions that may be estrogen receptor-dependent. Current work may aide in designing future studies to test further whether these BPA-substitutes can act as neuroendocrine disruptors.