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Decabromodiphenyl ether (BDE-209), as a brominated flame retardant (BFR), is widely applied to various consumer products due to its superior performance and affordable pricing to improve the flame resistance of materials. To better comprehend the pyrolysis behavior of BDE-209 and the evolution process of main pyrolysis products, the thermal degradation mechanism of BDE-209 was studied using density functional theory (DFT) method at the theoretical level of M06/cc-pVDZ, and thermodynamic parameters were calculated in this paper. Unimolecular degradation was dominated by cleavage of the ether linkage, which results in a high yield of hexabromobenzene, and fission of the ortho-position C-Br bond is the main competitive reaction channel. In the system of BDE-209 + H, the pyrolysis reaction is majorly characterized by debromination, leading to the formation of considerable HBr and low-brominated diphenyl ethers. Additionally, the hydrogen-derived splitting of the ether bond acts as a mainly competitive channel, which is the source of polybromophenols and polybromobenzenes. The formation of polybrominated dibenzofuran (PBDF) derives from the cyclization reaction of ortho-phenyl-type radicals, which are readily generated through the ortho-position Br atom abstraction by H radical. The formation of polybrominated dibenzo-p-dioxin (PBDD) involves the ortho-C-O coupling reaction of polybromophenoxy radicals, debromination reaction, and cyclization reaction. And the total yield of PBDD/Fs was significantly increased when H was involved. Results presented in this work will provide the helpful information for the treatment and reuse of BDE-209-containing waste plastics through using pyrolysis technology.

In this study, reduced graphene oxide (rGO) was used to fabricate a Z-scheme BiVO

Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDDs) have attracted extensive attention due to their strong persistence and toxicity. However, little has been known about their pollution status in fishing ports, which are typical sinks of land-sourced pollutants. In this study, we investigated the occurrence, distribution and ecological risk of TBBPA and HBCDDs in sediments from fishing ports along the coast of South China. The concentrations of TBBPA and ΣHBCDD (sum of α-, β-, and γ-HBCDD) in the fishing-port sediments were in the ranges of 0.02-21.5 ng/g dw and 1.06-14.1 ng/g dw, respectively. γ-HBCDD was the predominant diastereoisomer in most fishing-port sediments. The enantiomeric analysis indicated a preferential enrichment of (-)-enantiomers for α-, β-, and γ-HBCDD. The geographical location of fishing ports is a significant determinant of distribution for TBBPA and HBBCDs. The concentrations of TBBPA and HBCDDs in fishing-port sediments were strongly associated with local population density, but weakly correlated with total organic carbon content of the sediment. The mass inventories of TBBPA and ΣHBCDD were estimated to be 77.0 ng/cm

Passive air sampling (PAS) was used to evaluate organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), hexabromocyclododecanes (HBCDDs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and per- and polyfluoroalkyl substances (PFASs) in the atmosphere of Medellin, Colombia. This was in accordance with a special initiative of the Global Monitoring Plan (GMP), which was implemented to provide information on new and emerging persistent organic pollutants (POPs).PAS was carried out for three months (four quartiles per year) over two consecutive years (2017 and 2018), and two punctual peaks of contamination in the monitored time were observed. The first peak was related to chlorinated compounds in the quartile 2017-Q3, in which the highest concentration of pentachlorobenzene (PeCB, 755.5 pg·m-3) was observed, and air concentration of PeCB in quartile 2018-Q4 (125.0 pg·m-3) was 3.7 times more than the initial concentration (33.7 pg·m-3). These results may be associated with waste incineration in or near the city. The second peak of contamination was associated with brominated compounds in the quartile 2018-Q1, which could be linked to recycling, incineration, and landfill deposit of these compounds. In this peak, the highest levels of PBDEs and HBCDD-isomers were observed (Σ10PBDEs, 107.2 pg·m-3 and Σ3HBCDDs-isomers, 289.0 pg·m-3). With regard to the concentrations of PBDEs, HBCDDs, PCDDs, and PCDFs, these showed a slight tendency to increase between 2017 and 2018. Finally, constants concentrations of pollutants such as DDT isomers and dieldrin were observed, although these compounds were banned in Colombia many years ago. In contrast, a slight decrease in some pollutants, such as aldrin, and α-endosulfan, was observed.Our study allowed the assessment of air levels of chlorinated, brominated, and fluorinated pollutants in Medellin, Colombia. These results provide an overall view of POPs levels and represent an initial attempt to identify local sources in order to monitor and surveillance the releases of these pollutants in the city and country.

Tetrabromobisphenol A (TBBPA) is widely used in industrial production as a halogenated flame retardant (HFR). Its substitutes and derivatives are also commonly employed as HFRs. Consequently, they can be frequently detected in environmental and human samples. The potential developmental toxicity of TBBPA and its analogs, particularly to the human liver, is still controversial or not thoroughly assessed. Therefore, in this study, we focused on the early stages of human liver development to explore the toxic effects of those HFRs, by using a human embryonic stem cell liver differentiation model. We concluded that nanomolar treatments (1, 10, and 100 nM) of those pollutants may not exert significant interference to liver development and functions. However, at 5 μM doses, TBBPA and its analogs severely affected liver functions, such as glycogen storage, and caused lipid accumulation. Furthermore, TBBPA-bis(allyl ether) showed the most drastic effects among the six compounds tested. Taken together, our findings support the view that TBBPA can be used safely, provided its amounts are strictly controlled. Nonetheless, TBBPA alternatives or derivatives may exhibit stronger adverse effects than TBBPA itself, and may not be safer choices for manufacturing applications when utilized in a large and unrestricted way.

As a widely used brominated flame retardants (BFRs), tetrabromobisphenol A (TBBPA) has been detected in various environmental matrices and is known to cause negative effects on both the environment and human health. In this study, a combined method was developed for the abatement of TBBPA contaminated soil based on successive steps of solvent extraction (SE) and catalytic hydrodebromination (HDB) over Pd/C. The results showed that TBBPA could be efficiently extracted from the TBBPA contaminated soil with polar solvents. Subsequently, TBBPA could be completely hydrodebrominated over Pd/C in ethanol, via multistep ultimately yielding bisphenol A. Moreover, NaOH, NH

Present work depicted a novel electrochemical sensor fabricated with magnetic carbon dots (M-CDs) and cetyltrimethylammonium bromide (CTAB) modified glassy carbon electrode (GCE) for selective measurement of 3,3',5,5'-tetrabromobisphenol A (TBBPA) in beverages. The M-CDs composite material revealed good electrocatalytic activity, and CTAB has strong hydrophobic interaction which enable it have good enrichment capacity of hydrophobic compounds, and combination of them further enhances the electrochemical signal. Hence CTAB decoration can markedly improve the detection performance of TBBPA. Electrochemical properties of the fabricated sensor was investigated through performing cyclic voltammetry (CV). The morphology and functional groups of the modified materials were examined with transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). The results indicated that the synthesized material had a spherical-like structure, good dispersion properties and plenty of functional groups on the surface. The effects of incubation potential, incubation time, pH of electrolyte, and scanning rate on oxidation peak current were investigated. Under optimal conditions, the designed sensor had good linear range of 1 nM-1000 nM, and the detection of limit of the constructed sensor was 0.75 nM. The constructed sensor was utilized to detect TBBPA in vitamin water, scream drink and genki forest, and satisfactory detection performance had been achieved.

Marine bivalve molluscs are one of the primary seafood for consumers. Inhabiting terrigenous pollutant-convergent coastal areas and feeding through seawater filtration, edible bivalves are subjected to waterborne emerging pollutants such as microplastics (MPs) and tetrabromobisphenol A (TBBPA). Nevertheless, the potential risks of consuming MP-TBBPA contaminated seafood are still largely unknown. With that, accumulation of TBBPA with and without the presence of MPs in a commercial bivalve species, blood clam (Tegillarca granosa), was determined in the present study. Meanwhile, corresponding target hazard quotients (THQs) as well as margins of exposure (MoEs) were estimated to evaluate the potential health risks for clam consumers. Furthermore, the impacts of pollutants accumulation on the detoxification process and energy supply were analysed. The data obtained demonstrated that MPs aggravate the accumulation of TBBPA in clams, leading to elevated potential food safety risks (indicated by higher THQ values and lower MoE values) for consumers. In addition, the in vivo contents of CYP1A1 and UDP-glucuronosyltransferase, the enzymatic activity of glutathione-S-transferase, and the expression levels of five detoxification-related genes were all dramatically suppressed by MP-TBBPA. Furthermore, clams exposed to MP-TBBPA had significantly lower adenosine triphosphate contents and lower pyruvate kinase and phosphofructokinase activities. These results indicated that the aggravation of TBBPA accumulation may be due to the hence disruption of detoxification process and limited energy available for detoxification.

The widespread use of halogenated flame retardants in recent years has led to the accumulation of TBBPA in water, which may cause potential harm to living organisms. The phototransformation of the flame retardant TBBPA in alkaline saline water under simulated sunlight irradiation was investigated. The effects of abiotic factors such as the initial concentration of TBBPA, chloride ion concentration, solution pH, inorganic anions and cations, dissolved organic matter (DOM) were studied. The results showed that the phototransformation rate of TBBPA accelerated with the decrease of the initial concentration of TBBPA, the increase of chloride ion concentration and solution pH. The scavenging experiments showed that •OH, 1O2, O2•- and 3TBBPA* all participated in the phototransformation of TBBPA. The presence of NO3-, CO32-, SO42-, Mg2+, Ca2+, Fe3+ and fulvic acid (FA) all inhibited the phototransformation of TBBPA in the present study. The phototransformation products of TBBPA were detected by liquid chromatography-mass spectrometry (LC-MS), and the phototransformation pathways were proposed. This is the first report on the photo-induced generation of halogen exchange products from TBBPA in saline solutions, which will contribute to a better understanding of the environmental behavior and risks of BFRs in water.

Ferrous sulfide (FeS) and humic acid (HA) are typical black substances in black bloom water. Based on the strong reduction ability of FeS and the photosensitivity of HA, the transformation of toxic organic pollutants by the combination of FeS and HA (HA-FeS) is not clear. In order to explore this issue, the stability of HA-FeS was analyzed by measuring the hydrodynamic diameter and zeta potential of HA-FeS, and then the removal mechanism and possible degradation pathway of tetrabromobisphenol A (TBBPA) by HA-FeS under continuous illumination were discussed. The results showed that the hydrodynamic diameter of FeS was reduced and the stability of FeS was improved, and it was easily suspended after FeS combined with the HA in the water. The combination of HA and FeS promoted the removal of TBBPA in water, no matter it was in the presence or absence of light. Besides, compared with the absence of light, the removal efficiency of TBBPA was improved by HA-FeS with continuous light. There were two reasons for the increase in the removal efficiency of TBBPA by HA-FeS. On the one hand, Fe

Polybrominated diphenylethers (PBDEs), hexabromocyclododecanes (HBCDDs) and tetrabromobisphenol A (TBBPA) were monitored in various foods from terrestrial and aquatic animal origin (>850 samples), collected in the Netherlands between 2009 and 2014. The terrestrial samples included meat/fat from 7 animal species (including bovines, pigs, broilers and sheep), bovine milk and hen eggs. Dominant PBDE congeners in these samples were BDE-47, -99, -100, -153 and -183. The meat/fat generally contained the highest ∑PBDE concentrations compared to eggs and milk, with meat from deer, horse and sheep containing the highest concentrations. Generally declining ∑PBDE concentrations were observed between 2009 and 2014, however, this was only significant in pig meat and hen's eggs. The aquatic samples included fillets from 18 species (including herring, haddock and salmon), brown crab parts, shrimp and mussels, and the highest ∑PBDE concentrations were seen in body parts of brown crab, herring, mackerel, salmon and sea bass (on wet weight basis). Patterns generally contained more congeners (i.e., BDE-28, -49 and -66) additional to the aforementioned congeners found in terrestrial samples. Herring, sea bass and brown crab (body parts) contained among the highest PBDE concentrations. TBBPA was only detected in 3 individual samples (bovine and broiler meat and haddock), while α-HBCDD was the dominant diastereomer detected in several terrestrial and aquatic samples. When detected, TBBPA and HBCDD concentrations were generally in the same order as ∑PBDE concentrations in the same sample types.

This study systematically investigated the performance of ozonation on tetrabromobisphenol A (TBBPA) degradation under different ozone dosages (5.21–83.33 μmoL/L), initial solution pH (3.0–11.0) and temperatures (10–50 °C). At the same time, the generations of inorganic products (bromide ion and bromate) under different experimental conditions were evaluated and the organic products were also identified. Then, the possible mechanism was proposed and verified by the quantum chemical calculation. In addition, variations and controlling of the toxicity were also analyzed, including acute toxicity, chronic toxicity and genotoxicity. Ozonation was proved to be an efficient and promising technology for removing TBBPA from water. TBBPA of 1.84 μmoL/L could be completely degraded within 5 min under the ozone dosage of 41.67 μmoL/L in wide ranges of pH (3.0–11.0) and temperature (10–40 °C). During the degradation of TBBPA, over 65% of the average bromine ion was detected and nine products were identified. The proposed degradation pathways verified that TBBPA might undergo addition and stepwise oxidative debromination, the hydrogen extraction, and the deprotonation. The results of toxicity testing showed that ozonation could effectively control the acute and chronic toxicity of the water samples, although the toxicity increased in the initial reaction stage due to the accumulation of more toxic intermediates.

Polybrominated diphenylethers (PBDEs) are persistent organic pollutants (POPs), they are considered endocrine disruptors and can bioaccumulate in nature, and in living tissue. Human exposure to and the presence of PBDEs in human samples is of concern due to their potential health risks. Young children are one of the most vulnerable populations to PBDE's potential health effects. Ninety-one serum samples of 6-year-old children, residing in a contaminated location, due to former production of polychlorinated biphenyls (PCBs), were analysed to examine children's exposure to PBDEs in Slovakia. Median serum concentrations found for individual PBDE congeners BDE-28+33, −47, −99, −100, −153, −154 and −183 were 0.015, 0.184, 0.079, 0.046, 0.176, 0.014, and 0.097 ng g−1 lipid weight, respectively. Children's preschool maturity was measured using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) test. In multivariate analyses BDE-153 serum concentrations were significantly inversely associated with WPPSI-III composite score (p = 0.011, β = −23.6), while adjusting for PCB-153 and sex. Significant negative associations were observed for BDE-153 serum concentrations (p = 0.002, β = −29.8) and WPPSI-III composite score, after controlling for PCB-118 and sex. Negative associations were also observed for BDE-47, BDE-100 and BDE-153, with different individual WPPSI subtest scores, after adjustment with PCB-153 and/or PCB-118 and sex. Serum concentrations of PCB-153 and PCB-118 were not statistically significantly associated with WPPSI-III composite score and individual subtest scores. These findings demonstrate adverse effects of PBDE serum exposure on preschool maturity of children, and PBDEs potentially negative impact on child neuropsychological development.

The Victoria Land (East Antarctica) is characterized by the presence of lakes and ponds where rare water is found during the Summer months. These freshwater ecosystems are an important resource for migrating seabirds that use them and leave there their droppings and feathers, contributing to enrich the water with organic matter. Persistent organic pollutants (POPs) are long-range transported to polar regions and their detection in the Antarctic ecosystems date back to the 1960s. Most studies have been related to POP concentrations in marine environment, and terrestrial ecosystems have been poorly investigated. This study reports the concentration of PBDEs (23 congeners) and PCBs (21 among non-, mono-, di-, and ortho congeners) in lake sediment, soil and vegetation mat (community of algae, cyanobacteria, bryophites) collected close to six lakes in the Victoria Land (74°31'S-74°97'S, 165°07'E-162°51'E): Edmonson Point 14 and 15A, Carezza, Enigma, Tarn Flat 20, Inexpressible Island 10B. The ∑PBDEs averaged 0.09-0.28 ng/g and BDEs 28, 47 and 154 were higher in mat and soils, while BDEs 183 and 47 in sediment samples. PCBs ranged0.003-0.807 ng/g and congeners nos. 114, 138, and 187 were the most abundant. In addition, TEQs were derived for the non-and mono-ortho PCBs detected and values were very low in each matrix (0.010 pg/g in the soil, 0.012 pg/g in sediment and mat). The long-range atmospheric transport can be confirmed as the most important POP source in Antarctica, although the scientific stations and seabird colonies may be potential local sources and contribute to contaminant release.

Dugongs (Dugong dugon) are an iconic and strictly herbivorous species. They inhabit coastal areas, which brings them in contact with urban and agricultural pollutant sources, yet their exposure and susceptibility to environmental pollutants is still largely unknown. The goal of this study was to investigate the presence of several legacy compounds such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and pesticides as well as naturally produced MeO-PBDEs in male and female dugongs from Moreton Bay (n =24), a semi-enclosed embayment close to Australia's third largest city, Brisbane. Results show that concentrations of all investigated compounds are low in general (

Levels of hexabromocyclododecane isomers α, β, γ, (HBCDDs) and tetrabromobisphenol A (TBBP-A) were determined in 24 representative samples of different wild fish and seafood species (benthic: N = 16; pelagic: N = 8) and 16 samples of farmed bivalve molluscs from the West Mediterranean Sea (FAO 37, 1.3 sub-area). An LC-MS/MS-based method with limits of quantification (LOQS) in the range of 0.01–0.05 ng g−1 fresh weight (fw) was utilized. While α HBCDD was found in 80% of the 24 wild species samples, β and γ congeners were found in 33% and 25%, respectively. ΣHBCDD content ranged from 0.03 (Aristeus antennatus) to 0.68 (Sardina pilchardus) ng g−1 fw as Upper Bound values across 2.00–4.46 trophic levels. In farmed molluscs, HBCDD congeners were always present and ranged from 0.22–0.52 ng g−1 fw, with the exception of one farm (1.23–2.06 ng g−1 fw), whose values suggest the presence of a regular emission source. TBBP-A levels always fell below the LOQ of 0.05 ng g−1 fw in all samples. The results are in good agreement with results of previous studies from the Mediterranean Sea. The Environmental Quality Standard for human health from fish and seafood local consumption was set at 165 μg g−1 fw. The Margin of Exposure of 490,020 as the ratio between the considered Health Based Guidance Level of 0.79 mg kg−1 body weight and the geo-referenced HBCDD intake (P95 fish and seafood intake; mean ΣHBCDD contamination) indicates no threat to food safety.

Hydroxylated bromodiphenyl ethers (OH-BDEs) can arise from monooxygenation of anthropogenic BDEs or through natural biosynthetic processes in marine organisms, and several OH-BDEs have been shown to be toxic. OH-BDEs are expected to form sulfate and glucuronide conjugates that are readily excreted, however there is little information on these pathways. We examined the human hepatic glucuronidation and sulfonation of 6-OH-BDE47, 2-OH-BDE68, 4-OH-BDE68 and 2-OH-6′methoxy-BDE68. Human liver microsomes and cytosol were from de-identified female and male donors aged 31 to 75 under an exempt protocol. Recombinant human SULT1A1, 1B1, 1E1 and 2A1 enzymes were prepared from bacterial expression systems. Sulfonation and glucuronidation of each OH-BDE were studied using radiolabeled co-substrates, 3′phosphoadenosine-5′phospho-35S-sulfate or uridine diphospho-β-D-14C-glucuronic acid in order to quantify the sulfated or glucuronidated products. The OH-BDEs studied were more efficiently glucuronidated than sulfonated. Of the compounds studied, 2-OH-BDE68 was the most readily conjugated, and exhibited an efficiency (Vmax/KM) of glucuronidation of 0.274 ± 0.125 mL/min/mg protein, mean ± S.D., n = 3, while that for sulfonation was 0.179 ± 0.030 mL/min/mg protein. For both pathways, all Km values were in the low μM range. Studies with human SULT enzymes showed that sulfonation of these four substrates was readily catalyzed by SULT1B1 and SULT1E1. Much lower activity was found with SULT1A1 and SULT2A1. Assuming that the glucuronide and sulfate conjugates are non-toxic and readily excreted, as is the case for most such conjugates, these studies suggest that OH-BDEs should not accumulate in people to the same extent as the parent BDEs.

Currently, more and more concerns are related to oxidative stress appearing in cells as a result of xenobiotics action. It has been found that selected brominated flame retardants (BFRs) can cause reactive oxygen species (ROS) induction at environmental concentrations. Excessive ROS induction can contribute to the redox imbalance in the cell. Therefore, the aim of our work was to evaluate the effect of selected BFRs on the activity of antioxidant enzymes, i.e. superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the level of reduced glutathione (GSH) in human erythrocytes. Erythrocytes were incubated with tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS), 2,4-dibromophenol (2,4-DBP), 2,4,6-tribromophenol (2,4,6-TBP) and pentabromophenol (PBP) in the concentration ranging from 1 to 100 μg/ml. This study has shown that the BFRs studied disturbed redox balance in human erythrocytes. TBBPA caused more significant decrease in antioxidant enzymes activities than other compounds examined. Among bromophenols studied, 2,4-DBP most strongly affected antioxidant system, which indicated that the number of bromine atoms in the molecule did not significantly affect the pro-oxidative properties of the BFRs examined.

Little is known about the presence of organophosphate flame retardants (OPFRs) as a substitute for polybrominated diphenyl ethers in developing countries. This study investigated - for the first time - concentrations, sources and exposure levels of OPFRs in the indoor and outdoor environments of Alexandria, Egypt, in dust and gas-phase samples. Passive samplers were deployed (n = 78) to determine gaseous concentrations, and various dust samples were collected from apartments (n = 25), working places (n = 14), cars (n = 18), and outdoors (OD, n = 30). Indoor concentrations (air: 7.0–64 pg/m3; dust: 150–1850 ng/g) were significantly higher than outdoor (2.0–16 pg/m3 and 83–475 ng/g) concentrations. Tris-1,3-dichloropropyl phosphate (TDCIPP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri (2-butoxyethyl) phosphate (TBOEP) and triphenyl phosphate (TPHP) dominated in all samples with more indoor variabilities. Profiles of OPFRs in OD and floor dust (collected from carpets and floors) were similar but differed from elevated fine dust (collected 1 m above the floor from all available surfaces), possibly due to the influence of carryover of OD by shoes. Despite the high uncertainty in dust – air partitioning coefficients, log transformed values showed significant linear relationships with log octanol – air-partitioning coefficients in all microenvironments, indicating an equilibrium partitioning between dust and vapor. Exposure assessment indicated the importance of the dermal exposure route for adults and ingestion route for children.

Polybrominated diphenyl ethers (PBDEs) were widely used as flame retardants in consumer products including electronic devices. Important routes of human exposure are contaminated food and contact with dust. In this study, we measured twelve PBDEs in household/workplace dust and blood plasma samples provided by 113 volunteers living in the Puget Sound region, WA and working at electronic waste (E-waste) recycling sites (n = 29) or non-specific indoor (n = 57) or outdoor occupations (n = 27). The volunteers in the outdoor group were also selected because of a history of high seafood consumption habits. Results indicated the sum PBDE levels varied between2.5 and up to 310 ng g

Tetrabromobisphenol-A (TBBPA), a typical brominated flame retardant, leaked from commercial products into the environments has attracted people's attention around the world. Ochrobactrum sp. T capable of degradation and mineralization of TBBPA was isolated in our early work. In this study, the identification of TBBPA-degrading gene from the strain was further carried out by combining whole-genome sequencing with gene cloning and expression procedures. In total, 3877 open reading frames were found within 3.9 Mb genome and seven of them were identified as dehalogenating-relating genes. One gene with a significant ability to degrade TBBPA was designated as tbbpaA. Sequence alignments analysis showed that it shared 100% identity with haloacid dehalogenases. Furthermore, tbbpaA gene was cloned and expressed into E. coli to achieve a constructed strain. Like the original strain, the constructed strain could degrade TBBPA (6 mg L−1) with 78% of debromination efficiency and 37.8% mineralization efficiency within 96 h. Gene expression study revealed that tbbpaA was up-regulated in the presence of TBBPA. Overall, we report the identification of a functional TBBPA-degrading gene in an aerobe, which can deepen the knowledge of enhancing TBBPA removal by Strain T at the genetic level and facilitate in situ TBBPA bioremediation.

The widespread use of polybrominated diphenyl ethers (PBDEs) inevitably leads to their occurrence in the atmosphere, soil, and sediment. Biomass, especially dry branches and fallen leaves, may act a large reservoir for PBDEs through atmospheric deposition or soil bioaccumulation. Thus, clarifying the sunlight-induced transformation behaviors of PBDEs on biomass is highly significant for our understanding on its natural self-purification process. In this work, the degradation kinetics and mechanisms of two common PBDEs congeners, decabromodiphenyl ether (BDE-209) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), on biomass were systematically studied under natural and simulated sunlight irradiation conditions. The highest photodegradation rate constant of BDE-209 and BDE-47 was observed on sour cherry (SC) and zoysia matrella (ZM), respectively, which was related to their larger light receiving area and poor crystallinity. Due to the higher apparent quantum efficiency, BDE-209 degrades faster than BDE-47 (0.063-0.223 vs 0.006-0.026 h

Degradation of tetrabromobisphenol A (TBBPA), an emerging micropollutant, by photo/Fe

Tetrabromobisphenol A (TBBPA) greatly impacts on ecosystems and human health due to its high environmental toxicity and persistence. Persulfate (PS) advanced oxidation technology to remove organic pollutants in soils has received intense attention. In this study, nanoscale zero-valent iron (nZVI) was synthesized through the borohydride reduction method to explore its activating potential towards PS to accelerate the degradation of TBBPA in soils. The degradation behaviors of TBBPA in soils were investigated by batch experiments. The degradation efficiency of TBBPA (5 mg kg−1) was 78.32% within 12 h under the following reaction conditions: 3 g kg−1 nZVI, 25 mM PS, and pH 5.5 at 25 °C. Notably, PS can be used effectively, and the pH changed slightly in the reaction system. Oxidative degradation of TBBPA is favored at higher temperatures and lower pH values, while it is inhibited when the amount of catalyst increases significantly. The coexisting heavy metal ions such as Zn(II) and Ni(II) inhibit TBBPA degradation, while Cu(II) accelerates the degradation. Radical scavenging and electron spin resonance (ESR) tests further confirmed the generation of SO4·−, ·OH, and O2·− in nZVI activated PS. The intermediates identified by gas chromatograph–mass spectrometry analysis indicated that TBBPA via debromination and the cleavage between the isopropyl group and one of the benzene rings complete degradation. These findings provide new insight into the mechanism of nZVI activation of PS and will promote its application in the degradation of refractory organic compounds.

Currently, Tetrabromobisphenol A (TBBPA) has been regarded as an emerging organic pollutant and efficient TBBPA elimination technology has been attracting increasing attention. In this work, a novel photocatalyst, MoS

The effects of polybrominated biphenyls (PBBs) on human health have previously attracted much attention, but recent studies of PBBs have been focused on BB-153 and a few other congeners. PBB concentrations in serum samples from residents of an area containing an electronic waste dismantling site were determined in this study. The total PBB concentrations (i.e., the sums of the concentrations of the 35 PBB congeners) were 229–1360 ng/g lipid. The BB-153 concentrations were markedly higher in the samples from people living in the electronic waste dismantling area than in samples from people living in a nearby control area. BB-153 was found in all of the samples from the study exposure area but the concentrations were relatively low (0.07–4.70 ng/g lipid). High BB-1 concentrations were found for the first time in serum from people living in both the electronic waste dismantling and control areas. The BB-1 concentrations were 211–1280 ng/g lipid. The retention times of the 35 PBB standards and PCBs (polychlorinated biphenyls) with similar structures were used to predict the retention times of unidentified PBB congeners to allow the PBB distributions in the serum samples to be identified. A total of 26 previously unidentified PBB congeners were identified in the human serum samples. BB-5, BB-35, BB-79, and BB-109 were found in >50% of the samples. The PBB patterns in the serum samples were different from the patterns previously found in serum after a PBB contamination incident in 1973, so the health risks currently posed by PBBs are worth studying.

This is the first study to bring evidence on the anaerobic biodegradation of TBBPA occurring during acidogenesis in domestic sewage at environmentally relevant concentrations by complex microbial communities. This was accomplished by continuously operating two anaerobic structured bed reactors (ASTBR) for over 100 days under acidogenic (Acidogenic Reactor, AR) and multistep methanogenic (Methanogenic Reactor, MR) conditions. In the AR, the temporal carbohydrates consumption and the acetic acid production were strongly correlated with TBBPA removal by the Pearson's test. The spatial concentration of TBBPA and carbohydrates along the MR and the kinetic degradation profiles corroborate the AR results. It is hypothesized that TBBPA biodegradation in the studied conditions occurs during acidogenesis via the cometabolism supported by non-specific enzymes and the metabolism (dehalorespiration) established by electrons donors such as H2, which are both produced during the macrocomponents breakdown in the early stages of the anaerobic digestion. The TBBPA mass balance showed that approximately 86.8 ± 0.05% and 97 ± 0.01% of the removed TBBPA was biodegraded in the AR and MR, respectively. Furthermore, TBBPA biodegradation went further than reductive debromination as total phenols were detected in the reactors' effluent.

The microbial community composition in aquatic ecosystems have received increased attention. However, the knowledge gap relative to the responses of bacterial, archaeal and fungal communities in co-contaminated river sediments remain poorly studied. Here, we investigated the changes of tetrabromobisphenol A (TBBPA) and copper (Cu) concentrations and the responses of microbial communities in co-contaminated sediments during long-term incubation. TBBPA concentrations significantly decreased over time, whereas Cu concentrations remained relatively stable over the 60-day incubation. Abundances of the bacterial 16S rRNA, archaeal 16S rRNA and fungal ITS genes ranged from 6.53 × 106 to 1.26 × 109 copies g−1, 1.12 × 106 to 5.47 × 106 copies g−1 and 5.33 × 103 to 7.51 × 104 copies g−1 in the samples, respectively. A total of 11, 6 and 5 bacterial, archaeal and fungal phyla were identified across all samples. Bacterial, archaeal and fungal communities mainly consisted of members from the phyla Proteobacteria and Acidobacteria, Methanomicrobia and Woesearchaeia as well as Agaricales and Helotiales, respectively. Fungal communities showed a stronger response to pollutant addition after a long incubation compared with bacterial and archaeal communities. The variance analysis results revealed that the bacterial, archaeal and fungal microbial communities of all treatments were distinctly distributed into two separated clusters according to incubation time. However, the three microbial communities did not significantly change in response to pollutant types, which was consistent with variation in relative abundances of the three microbial communities. These findings improve our understanding of the ecotoxicological effects of co-exposure on sediment microbial communities.

International audience; Brominated flame retardants (BFRs) are anthropogenic compounds that are ubiquitous in most manufactured goods. Few legacy BFRs have been recognised as persistent organic pollutants (POPs) and have been prohibited since the 2000s. However, most BFRs continue to be used despite growing concerns regarding their toxicity; they are often referred to as novel BFRs (nBFRs). While environmental contamination due to chlorinated POPs has been extensively investigated, the levels and spatiotemporal trends of BFRs are comparatively understudied. This study aims to reconstruct the temporal trends of both legacy and novel BFRs at the scale of a river corridor. To this end, sediment cores were sampled from backwater areas in four reaches along the Rhône River. Age-depth models were established for each of them. Polychlorinated biphenyls (PCBs), legacy BFRs (polybrominated diphenyl ethers - PBDEs, polybrominated biphenyls - PBBs and hexabromocyclododecane - HBCDDs) and seven nBFRs were quantified. Starting from the 1970s, a decreasing contamination trend was observed for PCBs. Temporal trends for legacy BFRs revealed that they reached peak concentrations from the mid-1970s to the mid-2000s, and stable concentrations by the mid-2010s. Additionally, individual concentrations of nBFRs were two to four orders of magnitude lower than those of legacy BFRs. Their temporal trends revealed that they appeared in the environment in the 1970s and 1980s. The concentrations of most of these nBFRs have not decreased in recent years. Thus, there is a need to comprehend the sources, contamination load, repartition in the environment, and toxicity of nBFRs before their concentrations reach hazardous levels.

In the present study, carbon isotope effects were investigated during the photodegradation of polybrominated diphenyl ethers (PBDEs) by compound-specific stable isotope analysis (CSIA). Five PBDE congeners (BDE 85, 99, 100, 153 and 154) in n-hexane were individually exposed to simulated sunlight for as long as 15 h, except for BDE 100 (24 h). Consecutive debromination of PBDE by photolysis in n-hexane was confirmed by the clear 13C enrichment of mother congeners and successive depletion of δ13C values for the photodegradation products with decreasing degree of bromination, which can be attributed to mass-dependent isotope fractionation. The observed variation in the isotope fractionation trends for the para-debrominated products might be linked to the different photocatalytic activities of the PBDE congeners. Higher fractionation was observed for penta-BDEs (ec=−2.2 ± 0.45‰ and −2.3 ± 0.26‰ for BDE 85 and BDE 99, respectively) compared to that for hexa-BDEs (ec=−1.7 ± 0.41‰, and −1.3 ± 0.12‰ for BDE 153 and BDE 154, respectively). Normal isotope effects (AKIE > 1) observed in our study supports the utility of CSIA for the evaluation of the photodegradation of PBDEs.

An ordered g-C

Polybrominated diphenyl ethers (PBDEs) are more frequently suspected with the induction of toxicity via signal transduction pathway of cytosolic aryl hydrocarbon receptor (AhR), the initial binding to which is assumed to be an essential prerequisite during the ligand-dependent activation. However, the AhR binding property and associated toxicity of PBDEs is yet to be clearly known for lacking insights into the structural requirements at molecular level. To understand the AhR binding property of PBDEs, the ligand binding domain (LBD) of AhR was simulatively developed on homologous protein after basic validation of geometrical rationality and the binding interaction profile was visually described using molecular docking approach. For AhR binding, the offset or edge-on π-π stackings with aromatic motifs including Phe289, Phe345 and His285 were shown to be structurally required whereas the electrostatic attraction validated for AhR binding to dioxins might be less effective for 2,2',3,4,4'-pentabromodiphenyl ether (BDE-85). Besides the demands of less steric hindrance from alanines and weak formulation of hydrogen bonds, the dispersion force through large contact and polarization of S-π electrons seemed to be impactful when BDE-85 were closer to Cys327, Met334 or Met342. With theoretical computation of AhR binding energies, the more significant correlativity with bioassays was derived especially for the lowly/moderately brominated congeners, and could be used to predict the AhR binding affinity on certain degree. The informative results would thus not only help well understand the molecular basis of AhR-mediated toxicity but give an approach for accelerative evaluation of AhR binding and toxicity of PBDEs.

Cadmium (Cd) and tetrabromobisphenol A (TBBPA) are two ubiquitous pollutants in soils and are often found together at electronic waste recycling sites. In this study, their toxicity as well as the accumulation and subcellular partitioning of Cd were determined in two ecologically different earthworms Eisenia fetida and Metaphire guillelmi exposed for 14 days to Cd (1 mg kg−1) and TBBPA (10, 50, 100, and 500 mg kg−1) alone and in combination. In general, Cd-TBBPA co-exposure resulted in synergistic effects in terms of acute toxicity, growth inhibition, histopathological changes in body walls, and oxidative stress responses to earthworms, moreover, M. guillelmi showed higher sensitivity than E. fetida. Principal component analysis showed that the two earthworm species differed in their biomarker expression patterns. In addition, Cd accumulation was significantly (P

Human biomonitoring is a reliable method for evaluating human exposure to specific contaminants. Although blood is an ideal matrix for monitoring purposes, it is regarded as an invasive matrix. Therefore, current developments in the field of human biomonitoring are based on introducing new methods that use non-invasive matrices, such as hair. In this study, we examined the efficiencies of several extraction methods for the analysis of hexabromocyclododecane (HBCD) and tetrabromobisphenol-A (TBBPA) in human hair. The selected pretreatment method was validated through a general QA/QC process that included spiking experiments, and then, the method was used for the determination of HBCD and TBBPA concentrations in scalp hair samples collected from individuals in Korea (n = 24) and Iran (n = 15). The HBCD and TBBPA concentrations in the collected hair samples ranged from ND to 3.24 ng g−1 and ND to 16.04 ng g−1, respectively. Significantly higher concentrations of TBBPA were found in hair samples from Korea than those in hair samples from Iran (p