Concentrations Of Tetrabromobisphenol A Research Articles

Visible light-induced photocatalytic degradation of tetrabromobisphenol A on platinized tungsten oxide

In this study, we investigated the degradation of the flame retardant tetrabromobisphenol A (TBBPA) using platinized tungsten oxide (Pt/WO3), synthesized via a simple photodeposition method, under visible light. The results of degradation experiments show a significant enhancement in TBBPA degradation upon surface platinization of WO3, with the degradation rate increasing by 13.4 times compared to bare WO3. The presence of Pt on the WO3 surface stores conduction band electrons, which facilitates the two-electron reduction of oxygen and enhances the production of valence band holes (hVB+) and hydroxyl radicals (●OH). Both hVB+ and ●OH are significantly involved in the degradation of TBBPA in the visible light-irradiated Pt/WO3 system. This was verified through fluorescence spectroscopy employing coumarin as a chemical probe and oxidizing species-quenching experiments. The analysis of degradation products and their toxicity assessment demonstrate that the toxicity of TBBPA-contaminated water is significantly reduced after Pt/WO3 photocatalysis. The degradation rate of TBBPA increased with increasing Pt/WO3 dosage, reached an optimum at a Pt content of 0.5 wt%, but decreased with increasing TBBPA concentration. The decrease in degradation efficiency of Pt/WO3 was minor, both in the presence of various anions and after repeated use. This study proposes that Pt/WO3 is a viable photocatalyst for the degradation of TBBPA in water under visible light.

Sub-inhibitory concentrations of tetrabromobisphenol A induce the biofilm formation of methicillin-resistant Staphylococcus aureus.

Biofilm formation by methicillin-resistant Staphylococcus aureus (MRSA) on indwelling medical devices complicates the treatment of infection. Tetrabromobisphenol A (TBBPA), a synthetic, lipophilic, halogenated aromatic compound widely used as an additive in plastics and electronic products, has raised environmental concerns due to its potential for bioaccumulation. This study investigated the impact of sub-inhibitory concentrations of TBBPA on MRSA biofilm formation. Crystal violet staining and confocal laser scanning microscopy analysis demonstrated that 1/8 MIC (0.5µg/mL) of TBBPA significantly stimulated MRSA biofilm formation (P < 0.0001). MTT assays indicated that the metabolic activity within the biofilms increased by 15.60-40.85% compared to untreated controls. Dot blot immunoassay, autolysis assay, and extracellular DNA (eDNA) quantification further revealed TBBPA enhanced the production of polysaccharide intercellular adhesin (PIA) and eDNA, which are key biofilm components. Additionally, TBBPA was found to enhance the production of staphyloxanthin, facilitating MRSA survival under oxidative conditions and in human whole blood. RT-qPCR analysis showed that TBBPA significantly upregulated genes associated with biofilm formation (icaA, atlA, sarA), staphyloxanthin biosynthesis (crtM and sigB), and oxidative stress responses (sodA and katA). These findings suggest that TBBPA promotes MRSA biofilm development and enhances bacterial resistance to adverse conditions, thereby potentially exacerbating risks to human health.

Strategies to turn adversity into profits: Potential roles of tetrabromobisphenol a and tetrachlorobisphenol a in promoting carbon sequestration and lipid accumulation in microalgae

Harnessing microalgae for photosynthetic carbon fixation and converting it into economically valuable products has emerged as an effective pathway to address the energy crisis and global warming. Consequently, research on enhanced microalgae carbon sequestration and the production of high-value products has become a hot topic in this field. Low concentrations of BPA can promote cell growth through hormonal effects. However, there are currently no research reports on its potential to enhance microalgae oil synthesis. This study focused on tetrabromobisphenol A (TBBPA) andtetrachlorobisphenol A (TCBPA), utilizing a 12-day flask experiment to investigate whether different concentrations of TBBPA and TCBPA can boost the photosynthetic carbon sequestration efficiency of Microcystis aeruginosa, Chlorococcum infusionum, and Navicula minima. The results revealed that TBBPA can increase the biomass of the three microalgae, while TCBPA (100 and 1000 ng/L) can only significantly enhance the biomass of Chlorococcum infusionum. In carbon fixation capacity, 100 and 1000 ng/L of TBBPA and TCBPA increased the carbon fixation capacity of all three microalgae, respectively. In lipid productivity, TBBPA increased the lipid productivity of Navicula minima, with a maximum promotion rate of 53.5 %. And TCBPA increased the lipid productivity of Chlorococcum infusionum by 30.2 %. The molecular docking results indicate that the binding affinity of TCBPA to Rubisco enzymes in the three microalgae species was higher than that of TBBPA. TCBPA exhibits a greater binding affinity with Rubisco enzymes in Microcystis aeruginosa and Navicula minimum. Results of biodiesel quality analysis indicate that TBBPA and TCBPA not only accumulate microalgae lipid yield and maintain microalgae growth but also slightly optimize biodiesel performance. This study contributes to understanding the positive ecological effects of TBBPA and TCBPA.

In vitro estimation of oral bioaccessibility of brominated flame retardants in indoor dust by fasted and fed physiologically extraction test

Aim: There is a dearth of information on in vitro oral bioaccessibility, challenging the evaluation of the health risks arising from indoor dust exposure to the brominated flame retardants, tetrabromobisphenol A (TBBPA), and hexabromocyclododecane (HBCDD). Here, we estimate the human oral bioaccessibility of TBBPA and HBCDD in indoor dust by applying the standardized bioaccessibility test under fasting (UBM-like test) and fed (FOREhST test) conditions. Methods: In vitro bioaccessibility of HBCDD and TBBPA of sixteen indoor dust samples was conducted under fasted and fed states. In the fed test, food components, including healthy and unhealthy food. The concentrations of HBCDD and TBBPA were analyzed using LC-MS/MS. Bioaccessibility was calculated from the ratio of the amount of HBCDD and TBBPA in a simulated gut solution to that in indoor dust. The average daily dose (EDDbioaccessibility) was calculated from the estimated daily intake and percentage of bioaccessibility. Results: The concentration of TBBPA and HBCDD in indoor dust ranged from 137 to 14,671 ng g-1 and &lt; 0.7 to 528 ng g-1, respectively. A higher bioaccessible concentration was observed in the small intestine than in the stomach and mouth. The condition of the fed state with food containing fat showed greater bioaccessibility of TBBPA and HBCDD at 74.0% ± 9.5% and 62.2% ± 10.1%, respectively. In contrast, the fed state with lower fat food containing fiber presented the lowest bioaccessibility with a mean of 54.7% ± 10.7% for TBBPA and 53.7% ± 10.8% for HBCDD. Moreover, children are more exposed than adults, especially those who ingest indoor dust with fatty food. Conclusion: The oral bioaccessibility of TBBPA and HBCDD in indoor dust was highest in the fed state with fatty food, followed by fasted and fed states with lower fat, higher fiber food. Similarly, the estimated daily dose (EDDbioaccessibility) for children exceeded that for adults. Therefore, this study indicated that food consumption is a factor influencing the bioaccessibility of TBBPA and HBCDD present in indoor dust.

Anaerobic treatment removing tetrabromobisphenol A and biota safety: How do tropical aquatic species respond to effluent toxicity over short- and long-term exposures?

Wastewater containing tetrabromobisphenol A (TBBPA), a commonly used flame retardant found in wastewater, can present significant toxic effects on biota, yet its impact on tropical freshwater environments is not well understood. This study explores the effectiveness of two independent anaerobic treatment systems, the acidogenic reactor (AR) and the methanogenic reactor (MR), for the ecotoxicity reduction of TBBPA-rich wastewater in four tropical freshwater species. Despite presenting good physicochemical performance and reduced toxicity of the influent for most species, AR and MR treatments remain acute and chronic toxicity. Overall, MR exhibited greater efficacy in reducing influent toxicity compared with AR. TBBPA bioaccumulation was observed in Chironomus sancticaroli after short-term exposure to 100% MR effluent. Multigenerational exposures highlighted changes in the wing length of C.sancticaroli, showing decreases after influent and AR exposures and increases after MR exposures. These findings underscore the need for ecotoxicological tools in studies of new treatment technologies, combining the removal of emerging contaminants with safeguarding aquatic biota. PRACTITIONER POINTS: Acidogenic and methanogenic reactors reduced the acute and chronic toxicity of wastewater containing tetrabromobisphenol A. Both treatments still exhibit toxicity, inducing short- and long-term toxic effects on four native tropical species. The aquatic species Pristina longiseta was most sensitive to effluents from acidogenic and methanogenic reactors. TBBPA concentrations recovered from Chironomus sancticaroli bioaccumulation analysis ranged from 1.07 to 1.35 μg g-1. Evaluating new treatment technologies with multiple species bioassays is essential for a comprehensive effluent toxicity assessment and ensuring aquatic safety.

Assessing the role of the graphene family nanomaterials (GFNs: Graphene, GO, rGO) in modifying the toxicity potential and environmental risk of flame retardant, tetrabromobisphenol-A (TBBPA) in the marine microalgae Chlorella sp.

In recent years, a growing concern has emerged regarding the environmental implications of flame retardants (FRs) like tetrabromobisphenol-A (TBBPA) and graphene family nanomaterials (GFNs), such as graphene, graphene oxide (GO), and reduced graphene oxide (rGO), on marine biota. Despite these substances' well-established individual toxicity profiles, there is a notable gap in understanding the physicochemical interactions within the binary mixtures and consequent changes in the toxicity potential. Therefore, our research focuses on elucidating the individual and combined toxicological impacts of TBBPA and GFNs on the marine alga Chlorella sp. Employing a suite of experimental methodologies, including Raman spectroscopy, contact angle measurements, electron microscopy, and chromatography, we examined the physicochemical interplay between the GFNs and TBBPA. The toxicity potentials of individual constituents and their binary combinations were assessed through growth inhibition assays, quantifying reactive oxygen species (ROS) generation and malondialdehyde (MDA) production, photosynthetic activity analyses, and various biochemical assays. The toxicity of TBBPA and graphene-based nanomaterials (GFNs) was examined individually and in combinations. Both pristine TBBPA and GFNs showed dose-dependent toxicity. While lower TBBPA concentrations exacerbated toxicity in binary mixtures, higher TBBPA levels reduced the toxic effects compared to pristine TBBPA treatments. The principal mechanism underlying toxicity was ROS generation, resulting in membrane damage and perturbation of photosynthetic parameters. Cluster heatmap and Pearson correlation were employed to assess correlations between the biological parameters. Finally, ecological risk assessment was undertaken to evaluate environmental impacts of the individual components and the mixture in the algae.

Bisphenol Chemicals in Surface Soil from E-Waste Dismantling Facilities and the Surrounding Areas: Spatial Distribution and Health Risk.

Electronic waste (e-waste) dismantling facilities are well-known bisphenol chemical (BP) sources. In this study, non-targeted screening combined with targeted analysis of BPs in surface soil from e-waste dismantling facilities and their surroundings revealed their presence, distribution, and exposure risk. A total of 14 BPs were identified including bisphenol A (BPA) and its novel structural analogs and halogenated BPs. The total concentrations of BPs ranged from 963 to 47,160 ng/g (median: 6970 ng/g) in e-waste soil, higher than those measured in surface soil from surrounding areas, i.e., 10-7750 ng/g (median 197 ng/g). BPA, tetrabromobisphenol A (TBBPA), and bisphenol F (BPF) were the dominant ones from the two areas. Concentrations of TBBPA and its debromination product from the surrounding area significantly decreased with increasing distances from the e-waste dismantling facilities. Estimation of daily intake via oral ingestion of soil suggests that current contamination scenarios are unlikely to pose health risks for e-waste dismantling workers and adults and toddlers living in the surrounding areas, with their intakes generally well below the tolerable daily intakes proposed for several BPs. However, the BPA intakes of workers exceeded the more strict tolerable daily intake for BPA established recently, which merits continuous environmental surveillance.

Inventorization and ecological risk assessment of tetrabromobisphenol A and hexabromocyclododecane in sediments from Guangdong coastal area of South China Sea

Brominated flame retardants (BFRs) exhibit excellent flame retardant properties and are widely used in various industries. Among the common BFRs, tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) pose substantial ecological and human health risks due to their extensive application and long-range transport. This study established 131 sample collection sites along the coast of the South China Sea (SCS) in Guangdong Province to assess the concentration, distribution, inventory, and ecological risk of TBBPA and HBCDs in surface sediments. The concentrations of TBBPA in SCS sediments ranged from < limit of detection (LOD) to 80 μg/kg dry weight (dw), and those of HBCDs from < LOD to 18 μg/kg dw. The diastereoisomers of HBCDs (α-, β-, and γ-HBCD) in the sediment samples accounted for 36 %, 13 %, and 51 %, respectively. Human activities, particularly those associated with nearby electronic waste disassembly and textile and garment industries, considerably influenced the dispersion of TBBPA and HBCDs. The inventories of TBBPA and HBCDs in Guangdong Province's SCS were estimated to be 3.2 × 105 kg and 7.2 × 104 kg, respectively. The average risk quotient values ranged from <0.01 to 0.016, indicating a low to negligible environmental risk. This study provides deeper insights into the distribution and scientific significance of HBCDs and TBBPA in SCS sediment samples, elucidates the current state of BFR contamination, and offers recommendations for future research on environmental safety and human health in the region.

The Effects of Tetrabromobisphenol A (TBBPA) on the Mussel Mytilus galloprovincialis: A Multi-Biomarker Approach

Tetrabromobisphenol A (TBBPA) is a fire-retardant containing bromine, produced in large quantities worldwide and extensively used in several industrial products. This compound was identified as a potential contaminant of the environment, causing toxicity to organisms. However, its toxicity remains poorly understood in marine bivalves. The first objective of this work was to evaluate the impact of TBBPA on mussels (Mytilus galloprovincialis) exposed for 28 days to various concentrations of TBBPA (0, 1, 10, and 100 µg·L−1), by assessing stress biomarkers’ responses (Glutathione S-transferase, superoxide dismutase, catalase, lipid peroxidation, total antioxidant capacity, total ubiquitin, caspase-3 and acetylcholinesterase). The results showed that lower concentrations (1 and 10 µg·L−1) were efficiently detoxified, as suggested by GST activities, which were supported by the responses of the other biomarkers. The most pronounced effects were observed in animals exposed to the highest concentration of TBBPA (100 µg·L−1), suggesting oxidative stress. Additionally, significant strong correlations were found between total antioxidant capacity and some biomarkers (superoxide dismutase and lipid peroxidation), showing that processes involved in oxidative stress fighting are working to avoid cell injury. In brief, mussels’ defense mechanisms were capable of dealing with exposure to the lower concentrations tested. Despite this, the risk of consuming shellfish or other fishery products contaminated with TBBPA should be a cause for concern.

Concentration of Tetrabromobisphenol-A in fish: systematic review and meta-analysis and probabilistic health risk assessment.

Tetrabromobisphenol A (TBBP-A) is an emerging pollutant that enters water resources and affects various marine organisms, such as fish. Consequently, numerous studies globally investigated TBBP-A concentrations in fish fillets of the current study were meta-analyze concentration of TBBP-A in fish fillets and estimate the associated health risks for consumers. The search encompassed international databases, including Science Direct, PubMed, Scopus, Embase, and Web of Science from January 1, 2005, to July 20, 2023. The ranking of countries based on the pooled (Mean) concentration of TBBP-A in fish was as follows: China (1.157 µg/kg-ww) > Czech Republic (1.027 µg/kg-ww) > France (0.500 µg/kg-ww) ∼ Switzerland (0.500 µg/kg-ww) > Netherlands (0.405 µg/kg-ww) > Germany (0.33 µg/kg-ww) > Sweden (0.165 µg/kg-ww)>UK (0.078 µg/kg-ww) > Belgium (0.065 µg/kg-ww) > South Korea (0.013 µg/kg-ww) ∼ Japan (0.013 µg/kg-ww) > Ireland (0.005 µg/kg-ww). The risk assessment showed that the carcinogenic and non-carcinogenic risks of TBBP-A in China and France are higher compared to other countries; however, within all countries, these risks were found to be within acceptable limits.

Insight into the interaction of tetrabromobisphenol A with sediment-derived dissolved organic carbon in a multiphase system by direct immersion solid phase microextraction

Tetrabromobisphenol A (TBBPA), a ubiquitously used commercial brominated flame retardant (BFR), has been widely detected in aquatic environments, and has aroused much attention due to its potential adverse effects on aquatic organisms. However, current research on the environmental fate and transport of TBBPA in the sediment–dissolved organic carbon (DOC)–water polyphase system is lacking. In this study, the sorption behavior of TBBPA in a water–DOC–sediment system was investigated using the direct-immersion solid-phase microextraction (DI-SPME) method, and the free dissolved concentration (Cw-SPME) and DOC adsorption concentration (CDOC) of TBBPA in water were measured by applying this DI-SPME approach. In addition, the effects of pH, ionic strength, and soluble organic concentration on the adsorption of TBBPA in the multiphase system were evaluated. The adsorption kinetics experimental results show that the adsorption behavior of TBBPA on sediments conforms to a linear model, suggesting that it could be mainly absorbed by sediments. The solid–water partition coefficient (Kd) of TBBPA was artificially reduced 1.54 times using the traditional liquid–liquid extraction method because the sorption behavior of the DOC was ignored, which could be accurately corrected using the DI-SPME method. The logKd and logKOC of TBBPA in the multiphase system were 4.12 ± 0.25 and 6.48 ± 0.25, respectively. Finally, the interference experiment revealed that the sorption behavior of TBBPA was affected by the pH, ionic strength (calcium ion), and humic acid concentration, apart from the lead ion concentration itself.

Photocatalytic degradation of tetrabromobisphenol A by Z-scheme WO3/ZnIn2S4 heterojunction: Efficiency, mechanism and toxicity evaluation

Occurrence of brominated flame retardants especially tetrabromobisphenol A (TBBPA) in water bodies poses a serious threat to aquatic ecosystems. Heterogeneous photocatalysis is a versatile technology that can efficiently degrade organic contaminants. However, existing studies on photocatalytic degradation of TBBPA are all achieved under intense light irradiation and high initial concentrations of TBBPA, which are far from real environmental conditions and not conducive to practical application. In this study, series of Z-scheme heterojunctions of WO3/ZnIn2S4 photocatalysts were prepared and used for the high-efficiency photocatalytic degradation of TBBPA at lower light irradiation intensity (100 W) and lower TBBPA concentration (5.4 mg/L). Among them, WO3/ZnIn2S4-3 (molar ratio of 1:3) exhibited the highest photocatalytic activity due to the formation of Z-Scheme heterojunction which effectively facilitated the separation of photogenerated charges and endowed WO3/ZnIn2S4-3 higher redox ability. Thus, under light illumination, 91.6% degradation of TBBPA was achieved at an initial pH of 8.0 within 150 min, with a pseudo-first-order rate constant of 0.01572 min−1. Electron spin resonance spectroscopy and radical scavenger experiments confirmed that ·O2− radicals were the primary reactive oxygen species driving the TBBPA degradation. By applying LC-MS/MS, the degradation products were identified and possible degradation pathways were proposed. Finally, potential toxicity for PBBPA and generated intermediates were evaluated using luminescent bacteria, which revealed the toxicity of PBBPA was reduced effectively during the photocatalytic degradation process. Overall, the Z-scheme WO3/ZnIn2S4 photocatalyst provides a promising way for the application of photocatalytic technology in actual wastewater treatment.

Co-occurrence of tetrabromobisphenol a and debromination products in human hair across China: Implications for exposure sources and health effects on metabolic syndrome

The large usage of Tetrabromobisphenol A (TBBPA) in consumer products leads to ubiquitous distribution globally, however, studies on the occurrence of their debromination compounds were rather scarce. Also, though many studies illustrate the effectiveness of hair analysis to assess human exposure to organic pollutants, evidence on the associations with health implications is still fairly limited. Herein, 598 participants from across China were employed to investigate chronic, low-level exposure to TBBPA and debromination products by hair analysis. The geomean concentrations of TBBPA, 2,2′,6-tribromobisphenol A (Tri-BBPA), 2,2′- and 2,6-dibromobisphenol A (Di-BBPA), and 2-monobromobisphenol A (Mo-BBPA) were 1.07, 0.145, 0.135, and 0.894 ng/g, respectively, indicating nonnegligible health risks of debromination products. Hair analyte levels correlated with population age and population density among sampling regions. Sexual- and spatial-variations were observed with higher concentrations in females and in E-waste recycling sites. Logistic regression models showed that TBBPA exposure (adjusted odds ratio (OR): 1.02, 95 % confidential interval (CI): 1.01–1.05) was positively associated with risk of metabolic syndrome by adjusting for various covariates. These findings imply usefulness of hair as an alternative biomonitoring tool to assess human exposure to TBBPA and relative health effects, which highlights public concerns on co-exposure to these chemicals.

Environmentally relevant exposure to tetrabromobisphenol A induces reproductive toxicity via regulating glucose-6-phosphate 1-dehydrogenase and sperm activation in Caenorhabditis elegans

Tetrabromobisphenol A (TBBPA), a ubiquitous brominated flame-retardant environmental pollutant, has been reported to cause reproductive toxicity by chronic exposure. However, the acute reproductive risk and mechanisms of TBBPA toxicity to individuals, especially at environmentally relevant levels, remains a topic of debate. In this study, Caenorhabditis elegans was used to investigate the reproductive toxicity of acute exposure to TBBPA at environmentally relevant doses. The reproductive end points (embryonic lethality ratio and brood size), oxidative stress, sperm activation, and molecular docking were evaluated. Results showed that, after 24 h of TBBPA treatment, even at the lowest concentration (1 μg/L), the embryonic lethality ratio of C. elegans increased significantly, from 1.63 % to 3.03 %. Furthermore, TBBPA induced oxidative stress with significantly increased expression of sod-3 in C. elegans, which further raised the level of reproductive toxicity through inhibiting the activation of sperm in nematodes. In addition, molecular docking suggested TBBPA might compete for the glucose-6-phosphate-binding site of glucose-6-phosphate 1-dehydrogenase, resulting in oxidative stress generation. Accordingly, our findings indicate that even acute exposure to environmental concentrations of TBBPA may induce reproductive toxicity through reducing sperm activation in nematodes.

Eight novel brominated flame retardants in indoor and outdoor dust samples from the E-waste recycling industrial park: Implications for human exposure

As alternatives for legacy brominated flame retardants, novel brominated flame retardants (NBFRs) have a wide array of applications in the electronic and electrical fields. The shift of recycling modes of electronic and electrical waste (e-waste) from informal recycling family workshop to formal recycling facilities might come with the change the chemical landscape emitted including NBFRs, however, little information is known about this topic. This study investigated the occurrence characteristics, distribution, and exposure profiles of eight common NBFRs and their derivatives in an e-waste recycling industrial park in central China and illustrated the differences in various functional zones in the recycling park. The highest level of ΣNBFRs in dust samples was found in e-waste storage area at median concentration of 27,400 ng/g, followed by e-waste dismantling workshops (23,300 ng/g), workshop outdoor area (7770 ng/g), and residential area outdoor (536 ng/g). In the e-waste dismantling associated dust samples, tetrabromobisphenol A bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), tetrabromobisphenol A (TBBPA) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) were the predominant components. This paper presented the first evidence regarding the occurrence characteristic and distribution of tetrabromobisphenol S (TBBPS), tetrabromobisphenol A bismethyl ether (TBBPA-BME) and tetrabromobisphenol S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE) in the e-waste associated dust samples. By comparing with previous studies performed in China, this paper also noticed the significant decrease of TBBPA concentrations in the dust probably due to the shift of e-wastes sources and recycling modes. We further assessed the risk of occupational workers exposure to NBFRs. The median EDI (estimated daily intake) value of ΣNBFRs among e-waste dismantling workers was 9.71 ng/kg BW/d with the maximum EDI value being 19.6 ng/kg BW/d, hundreds of times higher than those exposed by general population. The study raises great concern for the health risk of occupational exposure to NBFRs in the e-waste recycling industrial park.

TBBPA causes apoptosis in grass carp hepatocytes involving destroyed ER-mitochondrial function

Tetrabromobisphenol A (TBBPA) is the most-produced brominated flame retardant, which can be found in various industrial and household products. Studies have shown that TBBPA has hepatotoxicity, and could pose a risk to aquatic animals. The endoplasmic reticulum (ER) and mitochondria are two important organelles that are highly dynamic in cells, the homeostasis and orchestrated interactions of which are crucial to maintaining cellular function. The aim of this study was to explore the involvement of ER-mitochondria crosstalk in TBBPA-induced toxicity in aquatic animals' hepatocytes. Herein, we exposed grass carp hepatocytes (L8824 cells) to different concentrations of TBBPA. Our experimental results suggested that TBBPA exposure suppressed cell viability and caused apoptosis of L8824 cells. TBBPA treatment upregulated expressions of ER stress markers, increased reactive oxygen species (ROS) and mitochondrial Ca2+ levels, and reduced mitochondrial membrane potential (MMP) in L8824 cells. However, the pretreatment of 2-aminoethoxydiphenyl borate (2-APB) could alleviate TBBPA-induced cell apoptosis, ER stress, and mitochondrial dysfunction. Additionally, 2-APB pretreat relieved ER-mitochondrial contact and the expression of ER-mitochondrial function-related genes induced by high-dose TBBPA. Taken together, these results indicated that TBBPA caused grass carp hepatocyte apoptosis by destroying ER-mitochondrial crosstalk.

Brominated flame retardants in surface sediment from Western Guangdong, South China: Occurrence, distribution and toxicity in Caenorhabditis elegans

Sediment is the ultimate sink of environmental pollutants. A total of 128 surface sediment samples were collected from 8 rivers and 3 reservoirs in Maoming City, Guangdong Province. This study assessed the content and distribution of brominated flame retardants in sediments. The acute toxicity effects of tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) in sediments were evaluated using Caenorhabditis elegans as model organisms. The concentration of TBBPA in sediments ranged from not detected (ND) to 12.59 µg/kg and was mainly distributed in the central area, which was affected by the emission of TBBPA from residential and factory. The concentration of HBCDs ranged from ND to 6.31 µg/kg, and the diastereoisomer distribution was consistent, showing a trend close to the South China Sea. The composition pattern of HBCDs in the surface sediments from rivers were 41.73%–62.33%, 7.89%–25.54%, and 18.76%–40.65% for α-, β-, and γ-HBCD, respectively, and in the sediments from reservoirs were 26.15%–45.52%, 7.44%–19.23%, and 47.04%–61.89% for α-, β-, and γ-HBCD, respectively. When the sum of concentrations of TBBPA and HBCD in sediments were above high levels, reactive oxygen species in nematodes significantly increased, resulting in an oxidative stress response. Intestinal permeability was also enhanced, causing intestinal damage. In addition, in terms of this study, TBBPA had a greater impact on biotoxicity compared to HBCDs, and more attention should be paid to the toxic effects of the river ecosystem organisms in Maoming City, Guangdong Province. This study can complement the pollution database in the study area and provide basic data for pollution control.

Analysis of tetrabromobisphenol A and bisphenol A in plant sample-method optimization and identification of the derivatives.

Tetrabromobisphenol A (TBBPA) is the most abundant brominated flame retardant and bisphenol A (BPA) is often identified as the metabolic product of TBBPA. Both of them are highly bioconcentrated and show serious biological toxicity. In this study, an analytical method was optimized to simultaneously determine TBBPA and BPA in plant samples. Moreover, the uptake and metabolism of TBBPA in maize were investigated through hydroponic exposure experiment. The whole analysis procedure included ultrasonic extraction, lipid removal, purification by solid-phase extraction cartridge, derivatization, and detection by GC/MS. Optimizations were conducted for each pretreatment step above. After improvement, methyl tert-butyl ether (MTBE) was chosen as the extraction solvent; the lipid removal was conducted by repartition between organic solvent and alkaline solution. The best suitable pH condition is 2-2.5 for the inorganic solvent before used for further purification by HLB and silica column with the optimized elute solvent of acetone and mixtures of acetone and hexane (1:1), respectively. The recoveries of TBBPA and BPA spiked in maize samples were 69±4% and 66±4% with the relative standard deviation less than 5%, respectively, for the entire treatment procedure. Limits of detections were 4.10 ng/g and 0.13 ng/g for TBBPA and BPA in plant samples, respectively. In the hydroponic exposure experiment (100 μg/L, 15 d), the concentrations of TBBPA in maize cultivated in pH 5.8 and pH 7.0 Hoagland solutions were 1.45 and 0.89 μg/g in roots and 8.45 and 6.34 ng/g in stems, while they were all below the detection limit for leaves, respectively. The distribution of TBBPA in different tissues was as the following order: root>>stem>leaf, illustrating the accumulation in the root and the translocation to the stem. The uptake variations under different pH conditions were attributed to the change of TBBPA species, now that it shows greater hydrophobicity at lower pH condition as a kind of ionic organic contaminant. Monobromobisphenol A and dibromobisphenol A were identified as metabolisms products of TBBPA in maize. The efficiency and simplicity of the method that we proposed characterize its potential application as a screening tool for environmental monitoring and contribute to a comprehensive study of the environmental behavior of TBBPA.

Convenient green synthesis of Cu/Fe nanoparticles using pomegranate peel extracts and their performance for tetrabromobisphenol A removal.

In this work, pomegranate peel extracts were used as the green reducing agent to synthesize Cu/Fe nanoparticles (P-Cu/Fe nanoparticles) and removed tetrabromobisphenol A (TBBPA) in aqueous solution. P-Cu/Fe nanoparticles were amorphous and irregularly spherical. The surfaces of nanoparticles contained Fe0, Fe3+ oxides (hydroxides), and Cu0. The bioactive molecules from pomegranate peel were extremely important for the synthesis of nanoparticles. P-Cu/Fe nanoparticles had excellent removal performance for TBBPA, and 98.6% of TBBPA (5mg L-1) was removed within 60min. The removal reaction of TBBPA by P-Cu/Fe nanoparticles was well-fitted with the pseudo-first-order kinetic model. The Cu loading was critical for TBBPA removal with an optimum value of 1.0 wt%. A weakly acidic condition (pH 5) was more favorable for the removal of TBBPA. The removal efficiency of TBBPA increased with the rise of temperature and decreased with increasing initial TBBPA concentration. The activation energy (Ea) was 54.09kJmol-1, indicating that the removal of TBBPA by P-Cu/Fe nanoparticles was mainly surface-controlled. Reductive degradation was the main mechanism of TBBPA removal by P-Cu/Fe nanoparticles. In conclusion, green synthesized P-Cu/Fe nanoparticles using pomegranate peel waste show great potential for the remediation of TBBPA in aqueous solution.

Concentrations of Tetrabromobisphenol-A and hexabromocyclododecane in Thai child daycare centre dust and the exposure risk for young children

Children spend one-third of their day in child daycare centres, where they may be exposed to toxic chemicals, such as tetrabromobisphenol-A (TBBPA) and hexabromocyclododecane (HBCDD), from indoor dust. However, studies on the exposure of TBBPA and HBCDD in schools remain scarce, especially in Thailand, where no such study has yet been reported. Therefore, in this study, we collected dust samples from 20 child daycare centres in Thailand and analysed them for flame retardants, TBBPA and HBCDD. TBBPA was detected in all samples with a median concentration of 35 ng g−1 (range, 14–5017.7 ng g−1). The median level of HBCDD was lower than the quantitation limit (LOQ) with <LOQ to 86.6 ng g−1 of dust sample. The electronic density score was calculated from the number of electronic appliances divided by each sampled surface floor area that revealed an abundance of TBBPA in the dust in rooms with many electronic items. The use of electronic devices, especially printers, that were found to be related to the high TBBPA concentration in the room, should be minimised in child daycare centres. The children's exposure to these chemicals from dust was estimated for dust ingestion and dermal absorption. The combined exposure was lower than the established reference dose value, and the hazard quotient for children via these two pathways were ranged 0.7 × 10−6 – 2.7 × 10−4 for TBBPA and 1.8 × 10−5 – 4.9 × 10−5 for HBCDD, which did not exceed 1.0. Although there is uncertainty regarding the potential health effects of long-term exposure to these substances, it is undeniable that child daycare centres represent a source of exposure to these substances for children. Further investigation of other intake routes of several flame retardants in child daycare centres and identification of the sources of these substances is warranted to decrease children's health risks from exposure to these harmful substances in child daycare centres.