Concentrations Of Tetrabromobisphenol A Research Articles

Anaerobic co-metabolic biodegradation of tetrabromobisphenol A using a bioelectrochemical system

Tetrabromobisphenol A(TBBPA), a pollutant in industrial wastewaters, needs to be removed due to its high toxicity and persistence. The main biodegradation pathway for TBBPA has been studied, and bisphenol A(BPA), which is toxic to the environment, is recognized as the general terminal product. In this study, we explored a new approach for the anaerobic biodegradation of TBBPA in a bioelectrochemical system (BES) through co-metabolic degradation of TBBPA with glucose. The half-life of TBBPA was significantly reduced to 13.5h−1 at 25μg/l of TBBPA. With an increase in the concentration of TBBPA, the removal rates of TBBPA rose to more than eighty percent. Based on the analysis of the products, we found that the degradation products of TBBPA were 2,6-dibromo-4-(1-methyl-1-phenylethyl) phenol, (double-benzenes product) and 2,6-dibromo-4-(prop-1-en-2-yl) phenol (single-benzene product), rather than BPA. Simultaneously, we proposed two degradation pathways for TBBPA in a BES system. According to the microbial diversity analysis of the anode biofilm, we speculated that the microorganism responsible for the biodegradation of TBBPA was Azoarcus. Additionally, we briefly analyzed the effect of TBBPA on the performance of BES system to pave the way for the further analysis of the interaction between the TBBPA and the BES system.

Effects of hydrodynamic disturbances and resuspension characteristics on the release of tetrabromobisphenol A from sediment

Tetrabromobisphenol A (TBBPA) exists widely in river and lake sediments; it has raised growing attention in recent years as emerging contaminant due to its possible threats to the aquatic environment and human health. Using a specialized simulator, the relationships between hydrodynamic disturbances and resuspension characteristics were simulated, with an emphasis on microscopic characteristics. Furthermore, TBBPA release from sediment was studied in relation to hydrodynamic disturbances and resuspension characteristics. The results show that stronger water disturbances caused an increase in suspended solids concentration (SSC) and produced different behaviors of particle size distribution (PSD) and media diameter (D50) in the slight and large-scale resuspension situations. As for microscopic resuspension characteristics, the specific surface area (SSA) of suspended particulate matter (SPM) was very different from that of smooth particles. This difference may result from the fractal nature of the SPM. The fractal dimension (FD) of SPM was found to have a significant correlation with turbulent kinetic energy. TBBPA release into overlying water and adsorption onto SPM both increased with hydrodynamic disturbances; but the release into overlying water is more dominant. The TBBPA concentrations in SPM under different hydrodynamic conditions were significant related to SSA, indicating that SSA is a key factor affecting the TBBPA adsorption capacity of SPM. TBBPA concentrations in sediment decreased slightly with the increased hydrodynamic dispersion. Findings from this research show the importance of considering the hydrodynamic disturbance and resuspension characteristics in understanding TBBPA release behavior in aquatic environment.

Reductive transformation of tetrabromobisphenol A by sulfidated nano zerovalent iron

Recent studies showed that sulfidated nano zerovalent iron (S-nZVI) is a better alternative to non-sulfidated nano zerovalent iron (NS-nZVI) commonly used for contaminated site remediation. However, its reactivity with different halogenated pollutants such as tetrabromobisphenol A (TBBPA) remains unclear. In this study, we explored the reductive transformation of TBBPA by S-nZVI and compared it with that by NS-nZVI. The results showed that over 90% of the initial TBBPA (20 mg L−1) was transformed by S-nZVI within 24 h of reaction, which was 1.65 times as high as that for NS-nZVI. The TBBPA transformation by S-nZVI was well described by a pseudo-first-order kinetic model, whilst that by NS-nZVI was well fitted by a three-parameter single exponential decay model. After 11 weeks of aging, S-nZVI was still able to transform up to 56% of the initial TBBPA within 24 h of reaction; by contrast, the two-week aged NS-nZVI lost more than 95% of its original capacity to transform TBBPA. Moreover, S-nZVI showed only an approximately 20% decrease in its capacity to transform TBBPA in the seventh cycle, while NS-nZVI was no longer able to transform TBBPA in the fourth cycle. XPS analysis suggested the formation of FeS layer on S-nZVI surface and electrochemical analysis revealed an elevated electron transfer capacity of S-nZVI, which were likely responsible for the superior performances of S-nZVI in TBBPA transformation. While the transformation rate of TBBPA by S-nZVI decreased with increasing initial concentration of TBBPA, it showed an increasing trend with increasing S/Fe ratio and initial concentration of S-nZVI. The study indicated that S-nZVI has the potential to be a promising alternative to NS-nZVI for remediation of TBBPA-contaminated aquatic environments.

Aquatic bioaccumulation and trophic transfer of tetrabromobisphenol-A flame retardant introduced from a typical e-waste recycling site.

While the flame retardant chemical, tetrabromobisphenol-A (TBBP-A), has been frequently detected in the environment, knowledge regarding its species-specific bioaccumulation and trophic transfer is limited, especially in the highly contaminated sites. In this study, the components of an aquatic food web, including two invertebrates, two prey fish, and one predator fish, collected from a natural pond at an electronic waste (e-waste) recycling site in South China were analyzed for TBBP-A, using liquid chromatography-tandem mass spectrometry. The aquatic species had TBBP-A concentrations ranging from 350 to 1970pg/gwetweight, with higher concentrations in the invertebrates relative to the fish species. Field-determined bioaccumulation factors of TBBP-A in the two aquatic invertebrates were nearly or greater than 5000, suggesting that TBBP-A is highly bioaccumulative in the two species. The lipid-normalized concentrations of TBBP-A in the aquatic species were negatively correlated with the trophic levels determined from stable nitrogen isotope (δ(15)N) (r = -0.82, p = 0.09), indicating that this compound experienced trophic dilution in the current food web.

Hexabromocyclododecane and tetrabromobisphenol A in sediments and paddy soils from Liaohe River Basin, China: Levels, distribution and mass inventory

Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) are two kinds of brominated flame retardants and widely present in the environment and biota. The levels, spatial distributions and mass inventories of HBCD and TBBPA were investigated in sediments and paddy soils from the Liaohe River Basin in northeast China. The concentrations of ΣHBCD and TBBPA were in the range of not detected (nd) to 4.02ng/g dry weight (dw) and 0.03 to 4.06ng/g dw, respectively. γ-HBCD was dominated in sediments, while the abundance of α-HBCD was relatively high in paddy soils. The spatial distributions of HBCD and TBBPA in surface sediments and paddy soils indicated that the local point-input was their major source. The significant correlation between total organic carbon (TOC) contents and the HBCD levels suggested that TOC content also exerted an influence on the distribution of HBCD in sediments. Meanwhile, it was found that the irrigation with river water was not the major transportation pathway of HBCD and TBBPA in paddy soils. Based on the study, it was estimated that there were about 1.67tons HBCD and 2.20tons TBBPA deposited into sediments of the Liaohe River system every year. The total mass inventories of HBCD and TBBPA in sediments were far higher than that in paddy soils.

Hexabromocyclododecane and tetrabromobisphenol-A in indoor dust from France, Kazakhstan and Nigeria: Implications for human exposure

Concentrations of hexabromocyclododecane isomers (α-, β- and γ-HBCDs) and tetrabromobisphenol-A (TBBP-A) were measured – for the first time – in indoor dust from homes, offices and cars from France, Kazakhstan and Nigeria. ΣHBCDs in French and Kazakhstani house dust (median = 1351 and 280 ng g−1, respectively) were consistent with previous reports from the UK and Romania, respectively. Concentrations of ΣHBCDs in Nigerian domestic dust (median = 394 ng g−1) were substantially higher than those reported from Egyptian homes. In general, concentrations of ΣHBCDs in the studied microenvironments were higher than those of TBBP-A, which may be attributed to the major application of TBBP-A as a reactive flame retardant; rendering its release to dust more difficult. Statistical analysis revealed significantly lower ΣHBCDs in French houses than those found in both offices and cars, while ΣHBCDs in cars from Kazakhstan were higher (P < 0.05) than those in homes and offices. Moreover, TBBP-A concentrations in car dust from Nigeria were lower than those found in homes and offices. Exposure estimates revealed higher intake of HBCDs and TBBP-A by toddlers via indoor dust ingestion compared to adults. Combined with their low body weight, this can raise concerns over the potential adverse health effects of such high exposure in toddlers.

Facile electrochemical determination of tetrabromobisphenol A based on modified glassy carbon electrode

In this study, surface-functionalized nitrogen-doped graphene was prepared with 1, 3, 6, 8-pyrenetetrasulfonic acid tetrasodium salt in a simple way. The characteristics of the material were demonstrated by UV–vis absorption spectra, X-ray photoelectron spectroscopy, and electrochemical experiments. Then, the glassy carbon electrode was modified by the functionalized nitrogen-doped graphene and hexadecyltrimethylammonium bromide for tetrabromobisphenol A (TBBPA) determination. The oxidation current response of TBBPA was enhanced at the modified electrode and the mechanism was investigated. Upon the optimization of assay parameters, including pH value, accumulation potential and time, the oxidation current was linearly related to the concentration of TBBPA in the range of 0.01–1μM with a detection limit of 9nM. Moreover, the modified electrode was applied to detect TBBPA in water samples with simple, low cost, and high efficiency.

Determination of Bisphenol A, Tetrabromobisphenol A and 4-Tert-Octylphenol in Children and Adults Urine Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

Abstract A method of high performance liquid chromatography (HPLC) coupled with tandem mass spectrometry for quantitative determination of bisphenol A (BPA), tetrabromobisphenol A (TBBPA) and 4-Tert-Octylphenol (OP) in urine of children and adults was developed. The frozen urinary samples were unfrozen at room temperature, then extracted by liquid-liquid extraction, evaporated to dryness, and dissolved by methanol so as to be analyzed by LC-MS/MS. The calibration curves for the determination of the three target compounds were linear in the concentration range of 0.2–50 μg L −1 with the correlation coefficients ( R ) greater than 0.99. The quantitative limits (LOQ) for the three target compounds were 0.05–0.27 μg L −1 . The recoveries of different levels (5, 10 and 50 μg L −1 ) were in the range of 85.7%–118.6% and the relative standard deviations (RSD) are 4.1%–10.5% ( n = 3). This method was successfully applied to the determination of BPA, TBBPA and OP in urine samples from 20 groups of children and adults. The results showed that exposure concentrations of TBBPA and OP in urines sample of children and adults were basically same, but exposure levels of BPA had significant difference (children > adults).

Absorption and excretion of Tetrabromobisphenol A in male Wistar rats following subchronic dermal exposure.

Tetrabromobisphenol A (TBBPA) is widely used as a flame retardant and frequently detected in environmental and biological samples. In this study, male Wistar rats were repeatedly exposed by dermal application to 20, 60, 200 and 600 mg TBBPA/kg body weight during 90 days. Concentrations of TBBPA in serum, urine and feces after dermal exposure were determined. TBBPA concentrations in serum ranged from 19.04 to 427.20 g/g lipids. The percentage of TBBPA dose recovered in serum on the 90th day varied from 0.002 ± 0.002% to 0.013 ± 0.008%, and the percentage of dose excreted in urine varied from 0.004 ± 0.002% to 0.072 ± 0.027%, while the percentage of dose recovered in feces were 3.30 ± 0.61% to 11.13 ± 3.16%. The results showed that about 3.31-11.21% TBBPA was absorbed dermally under different dosing regimens. TBBPA was excreted mainly in feces and small only amounts were recovered in urine.

Tetrabromobisphenol A and hexabromocyclododecane alter secretion of IL-1β from human immune cells

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD), flame retardant compounds used in epoxy resin circuit boards and upholstery, contaminate the environment and are found in human serum. Lymphocytes and monocytes are immune cells that, among other functions, secrete pro-inflammatory cytokines such as interleukin (IL)-1β, an important regulator of immune responsiveness and tissue growth and repair. Thus, if its levels are dysregulated, loss of proper immune function and increased invasiveness of tumors could ensue. This study examines whether exposures to varying concentrations (0.05–5.0 μM) of TBBPA and HBCD for 24 h, 48 h and 6 days interfere with the ability of immune cells to secrete IL-1β. The immune cell preparations examined were human natural killer (NK) cells, monocyte-depleted (MD) peripheral blood mononuclear cells (MD-PBMC) and PBMC. Both increased and decreased secretion of IL-1β from all three types of cell preparation were seen with TBBPA exposures and were dependent on concentration and length of exposure. TBBPA induced changes varied considerably from donor to donor. Exposure to HBCD from 0.5–5.0 μM caused increases in IL-1β secretion after all lengths of exposures in all cell preparations. The specific HBCD levels at which increases occurred varied among donors. Examinations of the signaling pathway(s) responsible for the elevated secretion of IL-1β after HBCD exposure were carried out in MD-PBMC cells. Results revealed that MAPK pathways (ERK1/2 and p38) appear to be the targets of HBCD that lead to increased IL-1β secretion from immune cells.

Biotransformations of bisphenols mediated by a novel Arthrobacter sp. strain YC-RL1.

Arthrobacter sp. strain YC-RL1, capable of utilizing bisphenol A (BPA) as sole carbon source for growth, was isolated from petroleum contaminated soil. YC-RL1 could rapidly degrade BPA in a wide range of pH (5.0-9.0) and temperature (20-40 °C). Substrate analysis found that YC-RL1 could also degrade bisphenol F (BPF) and tetrabromobisphenol A (TBBPA). The maximum and minimum concentrations of BPA (0.2-600 mg/L), BPF (0.2-600 mg/L), and TBBPA (0.2-300 mg/L) for efficient biodegradation were detected. The released bromide ion and metabolic intermediates of BPF and BPA/TBBPA were detected, as well as the degradation pathways for BPF and BPA/TBBPA were deduced tentatively. The present study provides important information for the investigation of BPs degrading mechanism and the application of microbial remediation in BP-contaminated environment. This study is the first report about a genus Arthrobacter bacterium which could simultaneously degrade BPA, BPF, and TBBPA.

Tetrabromobisphenol A and heavy metal exposure via dust ingestion in an e-waste recycling region in Southeast China

This study was designed to investigate a prevalent brominated flame retardant tetrabromobisphenol A (TBBPA) and four heavy metals of Pb, Cr, As, Cd in dust samples (52 indoor and 52 outdoor) collected from residential houses in an e-waste recycling area in Southeast China. For TBBPA, the mean concentration in indoor dust (3435ng/g, dw) was higher than that in outdoor dust (1998ng/g, dw). For heavy metals, the mean concentrations of Pb, Cr, As, Cd were 399, 151, 48.13, and 5.85mg/kg in indoor dust, respectively, and were 328, 191, 17.59, and 4.07mg/kg in outdoor dust, respectively. Except for As, concentrations of TBBPA and other metals decreased with the increased distance away from the e-waste recycling center, suggesting significant contribution of e-waste activities. The daily exposure doses of TBBPA ranged from 0.04 to 7.50ng/kg-bw/day for adults and from 0.31 to 58.54ng/kg-bw/day for children, representing the highest values reported to date for TBBPA exposure via dust ingestion. Daily exposure doses of Cr, As, and Cd were all below the reference doses. However, daily exposure dose of Pb for children in areas near the e-waste processing center was above the reference dose, posing significant health concern for children in that region.

A comparative assessment of human exposure to tetrabromobisphenol A and eight bisphenols including bisphenol A via indoor dust ingestion in twelve countries

Tetrabromobisphenol A (TBBPA) and eight bisphenol analogues (BPs) including bisphenol A (BPA) were determined in 388 indoor (including homes and microenvironments) dust samples collected from 12 countries (China, Colombia, Greece, India, Japan, Kuwait, Pakistan, Romania, Saudi Arabia, South Korea, U.S., and Vietnam). The concentrations of TBBPA and sum of eight bisphenols (ƩBPs) in dust samples ranged from <1 to 3600 and from 13 to 110,000ng/g, respectively. The highest TBBPA concentrations in house dust were found in samples from Japan (median: 140ng/g), followed by South Korea (84ng/g) and China (23ng/g). The highest ∑BPs concentrations were found in Greece (median: 3900ng/g), Japan (2600ng/g) and the U.S. (2200ng/g). Significant variations in BPA concentrations were found in dust samples collected from various microenvironments in offices and homes. Concentrations of TBBPA in house dust were significantly correlated with BPA and ∑BPs. Among the nine target chemicals analyzed, BPA was the predominant compound in dust from all countries. The proportion of TBBPA in sum concentrations of nine phenolic compounds analyzed in this study was the highest in dust samples from China (27%) and the lowest in Greece (0.41%). The median estimated daily intake (EDI) of ∑BPs through dust ingestion was the highest in Greece (1.6–17ng/kgbw/day), Japan (1.3–16) and the U.S. (0.89–9.6) for various age groups. Nevertheless, in comparison with the reported BPA exposure doses through diet, dust ingestion accounted for less than 10% of the total exposure doses in China and the U.S. For TBBPA, the EDI for infants and toddlers ranged from 0.01 to 3.4ng/kgbw/day, and dust ingestion is an important pathway for exposure accounting for 3.8–35% (median) of exposure doses in China.

TBBPA causes neurotoxic and the apoptotic responses in cultured mouse hippocampal neurons in vitro.

Tetrabromobisphenol A (TBBPA) is a brominated flame retardant widely used in a variety of commercial and household products. TBBPA can become bioaccumulated in human body fluids, and also in different brain regions. The aim of the present study was to determine the viability and apoptosis of cultured mouse hippocampal neurons in vitro after exposure to TBBPA. Additionally, we examined the involvement of ROS generation in the effect of TBBPA. Primary hippocampal neuron cultures were prepared from Swiss mouse embryos on day 17/18 of gestation. The cultures were treated with TBBPA at concentrations ranging from 1nM to 100μM for 30min or 3, 6 or 24h. To study apoptosis, the activity of caspase-3 was measured, and apoptotic body formation was evaluated. To investigate the cytotoxic effect of TBBPA, the level of lactate dehydrogenase (LDH) was measured in the culture medium. Our results demonstrated that TBBPA concentrations ranging from 100nM to 100μM caused caspase-3 activation and apoptotic body formation. The cytotoxic effects of TBBPA were observed at concentrations ranging from 50nM to 100μM. To detect intracellular ROS, the fluorogenic dye H2DCFDA was used. We did not observe any significant increase in the level of cellular ROS in cultured cells after TBBPA treatment. However, in a cell-free model, TBBPA at concentrations ranging from 10 to 100μM interacted with H2DCFDA and enhanced the fluorescence signal. We suggest that the H2DCFDA assay cannot be used to measure TBBPA-stimulated cell-mediated ROS production.

A Novel Debromination of Tetrabromobisphenol A (TBBPA) by Hydrothermal Treatment with Reactive Minerals

Tetrabromobisphenol A (TBBPA) is widely used as a flame retardant and relatively persistent in the environment. There has been increasing interest in the developing alternative approach for its degradation and debromination. In this study, we explored the debromination of TBBPA by alkaline hydrothermal treatment with reactive minerals, namely iron powder, layered double hydroxide (LDH) and gibbsite. The effects of hydrothermal temperatures and time, the initial TBBPA concentrations, and additive amounts of reactive minerals on debromination were investigated. As a comparison, the conventional hydrothermal treatment with no additive as the control group was included. The UV-vis absorption spectra of TBBPA before and after debromination were studied as well. The results showed that increasing temperature was helpful for the improvement of debromination. It significantly increased by 223.5, 54.3 and 78.1% with increasing temperature from 140 to 160 °C for the control, iron power and LDH groups, respectively. When the hydrothermal time was shorter than a critical value, the debromination rate increased with time rising. A maximum rate of 79.9% was achieved for iron powder group after reaction for 8 h. The preferred initial TBBPA concentration was determined as 60 ppm for all groups. The optimum amounts of reactive minerals were not consistent and determined as 0.08 g for iron powder, 0.32 g for LDH and 0.16 g for gibbsite, respectively. The maximum absorption bands of TBBPA increased as the pH was raised. They were located at 209 and 308 nm for neutral TBBPA and increased to 211 and 311 nm for TBBPA-Na2CO3. New absorption bands in the wavelength region of 225-275 and 300-350 nm were observed, when TBBPA was subjected to hydrothermal treatment. Keywords: Brominated flame retardants (BFRs); tetrabromobisphenol A (TBBPA); debromination; hydrothermal treatment; UV-vis absorption spectra

Sorption-Desorption Characteristics of Tetrabromobisphenol A on Humin and Sediment of Lake Chaohu, China

Three components of sediments with regard to the sorption-desorption characteristics of tetrabromobisphenol A (TBBPA) in sediment water systems were investigated. Results show that the Freundlich and Langmuir model can describe the sorption behavior of TBBPA well. The calculated Γ max (maximum unit sorption quantity) values were 1.47, 2.13, and 3.65 mg/kg for mineral group (MG), clay group (CG), and humin group (HG) sediments, respectively. HG exhibited a stronger nonlinear behavior than did CG and MG. The order of sorption capability was as follows: HG > CG > MG. Desorption capability order was the opposite. Simultaneously, it was found that precipitation was the main sorption type for TBBPA on sediment. The contribution of precipitation sorption ranged from 45 percent to 70 percent within a TBBPA concentration ranging from 0.1 to 10.0 mg/L in the supernatant. This may be attributable to anomalous changes in the compounds9 ionic activity in combination with metal cations. Sorption-desorption experiments on clay sediment were also conducted at pH levels ranging from 3 to 14 and temperatures ranging from 4°C to 30°C. In this regard, the sorption of TBBPA decreased as pH and temperature increased gradually. Furthermore, sorption and desorption reached a dynamic equilibrium at pH 11.5 and at a temperature of 30°C, respectively. The release of TBBPA from sediment would be higher in summer than in the three other seasons, which may pose a potential ecological risk for aquatic life in lakes.

Bioaccumulative characteristics of tetrabromobisphenol A and hexabromocyclododecanes in multi-tissues of prey and predator fish from an e-waste site, South China.

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were analyzed in 12 tissues of prey (mud carp) and predator (northern snakehead) fish from an e-waste area, South China. The TBBPA concentrations in different tissues ranged from 0.03 to 2.85 ng/g wet weight (ww) in mud carp and 0.04 to 1.30 ng/g ww in northern snakehead. The concentrations of HBCDs ranged from 0.07 to 96.9 ng/g ww in mud carp and 0.18 to 240 ng/g ww in northern snakehead. HBCD levels in tissues were correlated with lipid content for both fish species, while this correlation was only found in mud carp for TBBPA. Meanwhile, northern snakehead exhibited higher HBCD levels but lower TBBPA levels than mud carps. These observations are attributed to the more polar and reactive properties of TBBPA than HBCDs. α-HBCD was the predominant diastereoisomer of HBCDs in all tissues of mud carp and northern snakehead, except for chyme of mud carp. All the analyzed tissues in mud carp showed an enrichment of (+)-α-HBCD enantiomer with EF (enantiomeric fraction) values of 0.53–0.62, but that in northern snakehead showed an enrichment of (−)-α-HBCD enantiomer with EF values of 0.35–0.5. Considering the fact that the mud carp is one of the diet items of northern snakehead, the different enantiomer accumulation characteristics of α-HBCD between the two fish species in the present study indicated that prey and predator fish could prefer to biotransform different enantiomers of α-HBCD.

Hexabromocyclododecane and Tetrabromobisphenol A Alter Secretion of Interferon Gamma (IFNγ) from Human Immune Cells

Hexabromocyclododecane (HBCD) and Tetrabromobisphenol A (TBBPA) are brominated flame retardant compounds. HBCD is used in polystyrene insulation, accumulates in living organisms and is highly toxic to aquatic organisms. TBBPA is mainly used in plastic, epoxy resin printed circuit board, and other electronic equipment. Interferon gamma (IFNγ) is an inflammatory cytokine that is produced by activated T cells and NK cells and regulates immune responsiveness. HBCD and TBBPA have been found in human blood and previous studies have shown that they alter the ability of human natural killer (NK) lymphocytes to destroy tumor cells. This study examines whether HBCD and TBBPA affect the secretion of IFNγ from human purified NK cells, monocyte‐depleted (MD) human peripheral blood mononuclear cells (PBMCs), and PBMCs. IFNγ secretion was measured by enzyme linked immunosorbent assay (ELISA). Results indicate that exposures of NK cells, MD‐PBMCs and PBMCs to different concentrations of HBCD and TBBPA (ranging from 5‐0.05 µM) for 24h, 48h, and 6 days influence the ability of immune cells to secrete IFNγ. Certain concentrations of HBCD caused increases in IFNγ secretion after 24 and 48 h exposures (all cell preparations). However, TBBPA decreases secretion of IFNγ from NK cells and MD‐PBMCs but at certain concentrations is able to increase secretion of IFNγ from PBMCs. Thus, exposure to these compounds may potentially disrupt the immune regulation mediated by IFNγ. Additional studies were carried out addressing the signaling pathways that may be involved in HBCD‐induced increases in IFNγ secretion.

Brominated flame retardants in Korean river sediments, including changes in polybrominated diphenyl ether concentrations between 2006 and 2009

Brominated flame retardants were analyzed in sediment samples from the Nakdong River basin, Korea. The total concentrations of the 27 polybrominated diphenyl ethers (PBDEs), including decabrominated diphenyl ether (BDE 209), analyzed were 0.55–300ngg−1 dry weight (dw), the BDE 209 concentrations were 0.39–190ngg−1dw, the tetrabromobisphenol A (TBBPA) concentrations were 0.05–150ngg−1dw, and the total hexabromocyclododecane (sum of α-, β-, γ-HBCDs) concentrations were 0.11–19ngg−1dw. The PBDE and HBCD concentrations were comparable to or lower than the concentrations found in sediments from other countries, whereas the TBBPA concentrations were comparable to or higher than the concentrations found in other countries. The TBBPA concentrations were similar to or lower than the PBDE concentrations, even though more than twice as much TBBPA as total PBDEs is consumed in Korea, and this phenomenon was probably caused by TBBPA and PBDEs being used differently during the manufacture of products, and their different half-lives in sediment and affinities for the particle phase in aquatic environments. Sediment samples from several sampling sites close to facilities where expandable polystyrene, epoxy, and polycarbonate resins are manufactured and handled had relatively high TBBPA and HBCD concentrations. Temporal changes in the PBDE concentration strongly correlated with temporal variations in the geochemical compositions such as total organic carbon content and grain size value of the sediment. The PBDE and HBCD distribution profiles in the sediment samples indicated that commercial PBDE and HBCD products were released locally.

The effects of composite photosynthetic bacterial inoculant PS21 on the biochemical characteristics of wheat seedlings under tetrabromobisphenol A stress

The aim of this study was to investigate whether the composite photosynthetic bacterial inoculant PS21 alleviate the damage inflicted on wheat seedlings by tetrabromobisphenol A (TBBPA). The biochemical characteristics of wheat seedlings were analysed through laboratory simulation after co-treating seedlings with PS21 and 0, 5, 10, 20, 40, 80 and 100 mg kg−1 TBBPA, respectively. The results showed that TBBPA reduced the total chlorophyll content and increased the malondialdehyde (MDA) content. TBBPA increased the soluble sugar content, soluble protein content and activate superoxide dismutase (SOD; EC: 1.15.1.1), catalase (CAT; EC: 1.11.1.6) and peroxidase (POD; EC: 1.11.1.7) at low concentrations, while it reduced soluble sugar content, soluble protein content and decreased the activities of SOD, CAT and POD at high concentrations. At the concentration of 107 CFU mL−1, PS21 could markedly relieve the toxicity of different concentrations of TBBPA on wheat seedlings. Wheat seedlings treated with both TBBPA and PS21 showed a higher soluble sugar content, higher soluble protein content, higher SOD, CAT and POD activities, and a lower MDA content as compared to those treated only with TBBPA. The composite photosynthetic bacterial inoculant PS21 significantly alleviates the damage inflicted on wheat seedlings by TBBPA.