Article

Biotransformation of the flame retardant tetrabromobisphenol-A (TBBPA) by freshwater microalgae

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Abstract

Tetrabromobisphenol-A (TBBPA) is the most widely used brominated flame retardant. However, little is known about its biotransformation by algae in aquatic environments. We investigated transformations of TBBPA by six freshwater green microalgae and identified its transformation products. The transformation experiments were conducted under axenic conditions in laboratory for 10 days. The results showed that TBBPA could be transformed by the selected microalgae, with nearly complete removals by Scenedesmus quadricauda and Coelastrum sphaericum following 10 days' incubation. Five transformation products were positively identified by mass spectrometry, and they were: TBBPA sulfate, TBBPA glucoside, sulfated TBBPA glucoside, TBBPA monomethyl ether, and tribromobisphenol-A. The mechanisms involved in the biotransformation of TBBPA include sulfation, glucosylation, O-methylation and debromination, which could be an important step for its further degradation. This suggests that microalgae can play an important role in the fate of TBBPA in aquatic environments. This is the first report on algal transformation of TBBPA, and the proposed transformation products could have significant environmental implications. Environ Toxicol Chem © 2014 SETAC

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... Algae are ubiquitous as the primary producer with abundant biomass in aquatic ecosystems (Cooganet al., 2007). Previous literature demonstrated that algae can remove organic contaminants, such as nonylphenol, progesterone and norgestrel through bioadsorption, bioaccumulation as well as biodegradation process (Gao and Tam, 2011;Peng et al., 2014aPeng et al., , 2014bWarshawsky et al., 1988;Xiong et al., 2016Xiong et al., , 2017Zhou et al., 2012). Among the above three processes, the biodegradation has been proven to be the most effective way to eliminate organic contaminants from the aqueous phase due to the complex enzyme system that comprised of phase I (e.g., cytochrome P450) and phase II enzyme families (Xiong et al., 2018). ...
... Slower biodegradation rates have been reported for levofloxacin and carbamazepine by S. obliquus, with the half-lives in the range of 5e471 d and more than 10 d, respectively (Xiong et al., 2016(Xiong et al., , 2017. Nevertheless, the biodegradation rates of norgestrel and progesterone by S. obliquus were much faster than CBZ, with half-lives of 40 h and 16 h, respectively (Peng et al., 2014b). ¼ 3). ...
... (Table 2). This is in accordance with the demonstration that biotransformation was the major way to remove nonylphenol (NP), octylphenol (OP), progesterone and other organic compounds by S. obliquus or other microalgae species (Nakajima et al., 2007;Peng et al., 2014b). Overall, the alga S. obliquus had a high capability to remove CBZ, indicating a good prospect for its use in the wastewater treatment and bioremediation of contaminated aquatic environments. ...
Article
Climbazole (CBZ) is an antibacterial and antifungal agent widely used in personal care products. In this study, we investigated the interactions between climbazole (CBZ) and freshwater microalgae Scenedesmus obliquus (S. obliquus). Dose-effect relationships between CBZ concentrations and growth inhibitions or chlorophyll a content were observed. After 12 days of incubation, the algae density and chlorophyll a content in 2 mg/L treatment group was 56.6% and 15.8% of those in the control group, respectively. Biotransformation was the predominant way to remove CBZ in the culture solution, whereas the contribution of bioaccumulation and bioadsorption were negligible. More than 88% of CBZ was removed by S. obliquus across all treatments after 12 days of incubation, and the biotransformation of CBZ followed the first order kinetic model with half-lives of approximately 4.5 days at different treatments. CBZ-alcohol (CBZ-OH) was the only biotransformation product identified in algal solution. Moreover, the toxicity of biotransformation products was much lower than its corresponding precursor compound (CBZ). The results of this study revealed that S. obliquus might have a great impact on the environmental fates of CBZ and could be further applied to remove organic pollutants in aquatic environment.
... It provides a promising choice for the restoration of organic compounds contaminated environments due to its efficiency and environmental compatibility (Basak et al., 2014). Microorganisms, plants and animals in the natural environment are supposed to play an important part in the transformation process of TBBPA, such as cultured plant cells , enzymes secreted by plants (Lu et al., 2015(Lu et al., , 2017, microalgae (Peng et al., 2014), strains and communities (Gu et al., 2016;Peng et al., 2017;Xu et al., 2018), fungi and laccase (Feng et al., , 2017bUhnáková et al., 2011). ...
... As a result of fungal transformation, two products (product B and product D) showed higher molecular weight than TBBPA, indicating a possible addition of certain functional groups to the original chemical structure of TBBPA by P. chrysosporium. They were identified as monoglucosylated derivative of TBBPA (Peng et al., 2014) and monoglucosylated derivative of Tri-BBPA, respectively. Product E was tentatively identified as a monohydroxylated product of TBBPA (Zalko et al., 2006). ...
... As shown in Table 1 and Figs. S1-S8, we found that monoglycosylated TBBPA (product B), as a TBBPA derivative, was discovered during microalgae biotransformation (Peng et al., 2014), in which the TBBPA metabolite with a molecular weight of 706 was identified as a TBBPA glycoside. Noteworthy, to our knowledge, this is the first time to report tribromobisphenol A glycoside (product D) as TBBPA metabolite, suggesting that P. chrysosporium could not only achieve TBBPA debromination but also transform it to glycosides. ...
Article
The investigation of tetrabromobisphenol A (TBBPA) removal by Phanerochaete chrysosporium (P. chrysosporium) was conducted. Under optimal conditions (pH 5, inoculum size of 5% (v/v), initial glucose concentration of 5 g/L, TBBPA concentration of 5 mg/L), >97% of initial TBBPA was removed after 3 days. The TBBPA metabolites, tetrabromobisphenol A glycoside, tribromobisphenol A glycoside and monohydroxylated tetrabromobisphenol A, were identified for the first time by fungi transformation as being produced by glycosylation and oxidative hydroxylation, respectively. Proteome analysis showed that P. chrysosporium significantly upregulated cytochrome P450 monooxygenase, glutathione S-transferases, UDP-glucosyltransferase, O‑methyltransferase and other oxidoreductases for TBBPA oxidative hydroxylation, reductive debromination, glycosylation, O‑methylation and oxidative cleavage for detoxification. Data from cytotoxicity tests with human hepatocellular liver carcinoma (HepG2) confirmed that TBBPA toxicity was effectively decreased by P. chrysosporium treatment. Bioaugmentation with P. chrysosporium significantly improved the removal efficiency of TBBPA in water microcosms to 63.1% within 12 h. This study suggests that P. chrysosporium might be suitable for the removal of TBBPA from contaminated water.
... Carbon sources are also involved in TBBPA removal by other means rather than co-metabolic or metabolic functioning of microbial communities: complexation to organic matter. TBBPA glycoside and TBBPA glucoside (subcategory of glycosides) is formed by fungi (Chen et al. 2019b), microalgae species (Peng et al. 2014b), and pumpkin plants (Hou et al. 2019) by glycosylation reactions in which the glycosyl substitutions of the metabolites were bonded with an oxygen atom of the phenolic hydroxyl groups of TBBPA through the O-1glycosidic bond. These enzyme-mediated reactions contribute to TBBPA biotransformation and removal, even though they do not cause its degradation. ...
... The microorganisms and/or enzymes driving this process remains unknown and its occurrence on TBBPA break down is solely based on the transformation products identified. Beta-scission acts on the cleavage of a carbon-carbon bond and may generate from BPA, TBBPA or a less brominated bisphenol a variety of transformation products such as 2,6-dibromophenol and 4-(1-methylethenyl) phenol (Peng et al. 2014b;Barontini et al. 2004). ...
... O-methylation on halogenated compounds is the methylation of hydroxyl groups, which has been reported under aerobic conditions for TBBPA degradation (Peng et al. 2014b;Gu et al. 2016Gu et al. , 2018Liang et al. 2019a, b, c). The ability to O-methylate chlorophenols is widespread in nature and is performed by different bacterial genera and fungi species. ...
Article
Full-text available
The growing concern on the fate of toxic and persistent micropollutants in aquatic ecosystems led to the need to comprehend how these substances can be converted into less harmful chemicals. Tetrabromobisphenol A (TBBPA) is the most used brominated flame retardant (BFR) worldwide and is often detected in water bodies and wastewaters. In the past 20 years, the degradation of TBBPA has been investigated in bioreactors with different microbial communities and under a variety of operational parameters. Comprehending TBBPA biodegradation contributes to a better understanding of other flame retardants environmental fate and the optimization of wastewater treatment biotechnologies. Even though many process-optimization procedures and investigations on mixed and isolated strain functions have been conducted, understanding metabolic processes on this micropollutant breakdown remains uncovered, especially in environmental settings. Different findings on how to optimize TBBPA bioconversion and the factors influencing cometabolic and metabolic reactions may mislead further studies or suggest arguable directions. For this reason, this review summarizes and critically discusses how the main environmental and operational parameters affect TBBPA biodegradation, the main degradation pathways and subproducts, and the microorganisms and enzymatic activities involved in this process, raising some questions that should be addressed in more in-depth studies.
... For instance, TBBPA bis(methyl ether) (TBBPA BME) and TBBPA mono(methyl ether) (TBBPA MME) are the resultant transformation products of TBBPA via aerobic metabolism by bacteria [8]. Some products, such as TBBPA glucoside, could be formed as the result of biological transformation through the combination of TBBPA with biological molecules [9]. As some mono-modified TBBPAs can be formed due to the transformation of MTDs, these derivatives are created either by the transformation of MTDs or by the generation of by-products during manufacturing. ...
... As compared with abiotic reactions, biotic reactions are considered to be the main transformation pathways of TBBPA and can result in the presence of unknown brominated substances in environmental compartments [8,17,18]. With the development of analytical methods based on MS, various transformation products of TBBPA have been observed [8,9,[15][16][17][18][19][20][21]. However, there has been little or no documented investigation concerning the degradation of TBBPA derivatives. ...
... Pang et al. developed negative ESI-triple quadrupole-MS (ESI-QqQ-MS) for fast detection of brominated oxidation products, and several degradation products have been identified using this method (Fig. 4A) [15]. With high resolution, time-of-flight MS (TOF-MS) was also used for the analysis of biotransformation of TBBPA incubated with freshwater microalgae (Fig. 4A) [9]. ...
Article
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant. TBBPA and its alternative, tetrabromobisphenol S (TBBPS), are the reactive chemicals used to produce TBBPA/S derivatives. The manufacturing and application of TBBPA/S derivatives may result in their accumulation in environmental compartments and may cause risks to environmental safety and human health. To investigate the occurrence and transformation products of TBBPA/S and TBBPA/S derivatives, it is imperative to develop effective sample preparation and sensitive analytical methods for various environmental matrices. In this paper, we summarize the techniques for analysis of TBBPA/S and their derivatives. We also critically review methodologies for the identification of unknown metabolites transformed from these chemicals. In the perspective section, we discuss trends in analytical strategies for studying emerging TBBPA/S derivatives.
... It was reported that TBBPA was sulfated and conjugated with glucuronide(s) in rats and conjugated with glucoside(s) in microalgaes. 21,22 Whereas a lack of research on both comprehensive metabolic pathways and quantitative evaluation of biotransformation makes the metabolism of TBBPA in organisms difficult to predict. 23 To better elucidate the unknown parallel metabolic reactions in plants, hydroponic exposure experiments using pumpkin with a relatively high TBBPA concentration of 1 μmol L −1 were conducted in this research. ...
... The MS 2 spectrum of M9 ( Figure S5) shows that the quasimolecular ion [M+HCOOH-H] − has a neutral loss of a formic acid (HCOOH) and sequential neutral losses of two hexose groups (C 6 H 10 O 5 ), similar to the MS 2 behaviors of TBBPA DG, indicating that M9 has two hexose groups like TBBPA DG. In addition, M9 shows the typical anion of tribromobisphenol A (TriBBPA) at m/z 462.83632, 22 suggesting that M9 is the conjugation metabolites of TriBBPA. Therefore, M9 was finally inferred to be TriBBPA DG with confidence level 2b. ...
Article
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant (BFR) and it bioaccumulates throughout the food chains. Its fate in the first trophic level, plants, is of special interest. In this study, a four-day hydroponic exposure of TBBPA to pumpkin seedlings was conducted at a concentration of 1 μmol L-1. A non-target screening method for hydrophilic bromine-containing metabolites was modified, based on both typical isotope patterns of bromine and mass defect, and used to process mass spectrum data. A total of 20 glycosylation and malonyl glycosylation metabolites were found for TBBPA in the pumpkin plants. Representative glycosyl TBBPAs reference standards were synthesized to evaluate the contribution of this glycosylation process. Around 86% of parent TBBPA was metabolized to form those 20 glycosyl TBBPAs, showing that glycosylation was the most dominant metabolism pathway for TBBPA in pumpkin at the tested exposure concentration.
... O-methylation derivatives of TBBPA were commonly detected in soil, sludge, and sediment (George and H€ aggblom, 2008;Li et al., 2014Li et al., , 2015aLi et al., , 2015bSun et al., 2014). While knowledge about their presence in organisms is limited, diMeO-TBBPA has been detected in mussels (Watanabe et al., 1983) and MeO-TBBPA in microalgae (Peng et al., 2014), but there are no reports on TBBPA metabolites in terrestrial organisms. Studies in rats (Hakk and Letcher, 2003) and in microalgae (Peng et al., 2014) demonstrated the occurrence of metabolic phase II conjugation of TBBPA in biota. ...
... While knowledge about their presence in organisms is limited, diMeO-TBBPA has been detected in mussels (Watanabe et al., 1983) and MeO-TBBPA in microalgae (Peng et al., 2014), but there are no reports on TBBPA metabolites in terrestrial organisms. Studies in rats (Hakk and Letcher, 2003) and in microalgae (Peng et al., 2014) demonstrated the occurrence of metabolic phase II conjugation of TBBPA in biota. Thus, in our study the fraction of PMs with relatively high polarity presumably contained TBBPA conjugates. ...
Article
Tetrabromobisphenol A (TBBPA) is the world's most widely used brominated flame retardant but there is growing concern about its fate and toxicity in terrestrial organisms. In this study, two ecologically different earthworms, Metaphire guillelmi and Eisenia fetida, were exposed to soil spiked with ¹⁴C-labeled TBBPA for 21 days. M. guillelmi accumulated more TBBPA than E. fetida, evidenced by a 2.7-fold higher ¹⁴C-uptake rate and a 1.3-fold higher biota-soil accumulation factor. Considerable amounts of bound residues (up to 40% for M. guillelmi and 18% for E. fetida) formed rapidly in the bodies of both earthworms. ¹⁴C accumulated mostly in the gut of M. guillemi and in the skin of E. fetida, suggesting that its uptake by M. guillelmi was mainly via gut processes whereas in E. fetida epidermal adsorption predominated. The TBBPA transformation potential was greater in M. guillelmi than in E. fetida, since only 5% vs. 34% of extractable ¹⁴C remained as the parent compound after 21 days of exposure. Besides polar metabolites, the major metabolites in both earthworms were TBBPA mono- and dimethyl ethers (O-methylation products of TBBPA). Acute toxicity assessments using filter paper and natural soil tests showed that the methylation metabolites were much less toxic than the parent TBBPA to both earthworms. It indicated that earthworms used O-methylation to detoxify TBBPA, and M. guillelmi exhibited the higher detoxification ability than E. fetida. These results imply that if only the free parent compound TBBPA is measured, not only bioaccumulation may be underestimated but also its difference between earthworm species may be misestimated. The species-dependent fate of TBBPA may provide a better indicator of the differing sensitivities of earthworms to this environmental contaminant.
... To measure biomass (dry weight, DW), biofilm samples were dried at 80°C for more than 4 h until constant weight was obtained using an electronic balance. To extract the photosynthetic pigment, a previously described method was adopted (Peng et al., 2014). Briefly, biofilm samples were frozen (−20°C) for 20 min and thawed (25°C) for 5 min, which was repeated three times and followed by being frozen (−20°C) overnight until the cell walls were broken. ...
... TBBPA is mainly applied as a reactive flame retardant in printed circuit boards of electronic equipment, e.g., in computers, automobiles, and washing machines (Han et al. 2008;Debenest et al. 2010). Increased applications may lead to leakage of TBBPA into the environment, which may then result in its accumulation in biological systems (Hu et al. 2009;Peng et al. 2014;Liu et al. 2016a). TBBPA has been identified as a novel contaminant which may pose severe environmental risks to human (Beck et al. 2016) and other species (Wu et al. 2016). ...
Article
Full-text available
Combined toxicity and oxidative stress biomarker responses were determined for tetrabromobisphenol A (TBBPA) and sulfadiazine (SDZ) to the unicellular green alga Scenedesmus obliquus. Concentration–response analyses were performed for single toxicants and for mixtures containing TBBPA and SDZ with two different mixture ratios. The effect concentrations and the observed effects of the mixtures were compared to the predictions of the joint toxicity by the concentration addition (CA) model and independent action (IA) model. Results showed that the observed joint toxicity was within the scope of the highest (TBBPA) and lowest (SDZ) toxicity observed for the individual components. Furthermore, co-exposure of S. obliquus to TBBPA and SDZ provided preliminary evidence that the mixtures induced oxidative stress leading to cell damage. The CA and IA models proved to be valid for the prediction of the joint toxicity of TBBPA and SDZ. This study highlights a combined environmental risk assessment for two emerging pollutants.
... 13,18,21 Many organic and inorganic mediates, including TBBPA sulfate, debrominated products, oxygen-methylation products, bromopenols, nitro-brominated bisphenol A, etc. have been identified under different conditions. 13,16,18,20,21,31,32 However, the environment behavior and fate of the identified chemicals have not been well studied mainly because of the lacking of commercial available standards at present. 33 Meanwhile, the silico prediction is another quick, easy, and feasible way for organic pollutants transformation study and gives possible degradation products and metabolism pathway. ...
Article
In contrast to the extensive investigation already conducted on tetrabromobisphenol A (TBBPA), the metabolism of TBBPA derivatives is still largely unknown. In this paper, we characterized unknown brominated compounds detected in 84 soil samples collected from sites around three brominated flame retardants production plants to determine possible transformation products of TBBPA derivatives. In addition to tribromobisphenol A (TriBBPA), dibromobisphenol A (DBBPA) and TBBPA, six novel transformation products, TriBBPA mono(allyl ether) (TriBBPA-MAE), DBBPA-MAE, hydroxyl TriBBPA-MAE, TBBPA mono(2-bromo-3-hydroxypropyl ether) (TBBPA-MBHPE), TBBPA mono(2,3-dihydroxypropyl ether) (TBBPA-MDHPE), and TBBPA mono(3-hydroxypropyl ether) (TBBPA-MHPE) were identified. The detection frequencies of these identified chemicals in soil samples ranged from 17% to 89%, indicating the widespread presence of the transformation products. To uncover the possible TBBPA derivative transformation pathways involved, super-reduced vitamin B12 (cyanocobalamin, (CCAs)) was used to treat TBBPA derivative and transformation products in this process were characterized. To our knowledge, this is the first study examining the transformation of TBBPA derivatives and the first to report several novel associated TBBPA and bisphenol A derivatives as transformation products. Our research suggests that ether bond breakage and debromination contribute to the transformation of TBBPA derivatives and the existence of the novel transformation products. These data provide new insights into the fate of TBBPA derivatives in environmental compartments.
... TBBPA has been widely detected in soils, with a concentration as high as 7.7 mg/kg dry soil in Shandong Province, China (Liu et al., 2016;Ren et al., 2013). In complex soil systems, diverse oxidative and reductive metabolites of TBBPA have been detected, including products of debromination, O-methylation, and side-chain cleavage Peng et al., 2014).In soils and sediments, large amounts of TBBPA-derived bound residues have been formed McAvoy et al., 2016;Luo et al., 2016). Li et al. (2015a) found that TBBPA and its polar and mono-methylated metabolites bind to soil via ester linkages, but these compounds only comprised b10% of the total bound residues in soil. ...
Article
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants worldwide. The degradation and fate of this organic pollutant of soils is of great concern and can be strongly affected by geophagous earthworms through ingestion and burrowing activities. Using (14)C-tracers, we studied the effects of the geophagous earthworm Metaphire guillelmi on the mineralization, metabolism, and bound-residue formation of TBBPA in a typical Chinese rice paddy soil during 30days of incubation in the laboratory. Earthworms significantly decreased both mineralization (from 3.9±0.3% of the initial amount to 2.6±0.2%) and dissipation (from 90.6±0.6% to 84.1±1.2%) of TBBPA in the soil, and stimulated the generation of O-methylation metabolites (TBBPA methyl ethers; from 1.4±0.4% to 15.4±0.6%). This resulted in a strong decrease in bound-residue formation of TBBPA and its metabolites in the soil (from 80.3±0.4% to 41.8±3.1%). Results from a first-order, two-compartment model that describes the fate of TBBPA in soil indicated that the TBBPA-derived bound residues were mainly attributed to the binding of metabolites to the soil matrix and not to the binding of TBBPA, and that earthworms reduced the kinetic rates of both polar metabolite generation and their bound-residue formation. Our results suggested that the geophagous earthworm Metaphire guillelmi strongly influenced the fate of TBBPA by altering the composition of metabolites and therefore bound-residue formation. The increased persistence of TBBPA and the formation of persistent O-methylation metabolites by M. guillelmi would increase the environmental risk of TBBPA.
... Microalgae-based wastewater treatment (WWT) technologies provide interesting capabilities for combining energy-efficient macro-pollutant (C, N, P) removal with biomass valorisation ( Craggs et al., 2012Craggs et al., , 1997Park et al., 2011a) as well as, potentially, hazardous pollutant biodegradation by microalgae and/or microalgal-bacterial consortia ( Peng et al., 2014aPeng et al., , 2014bMu~ noz and Guieysse, 2006). However, the fate of emerging micropollutants, such as endocrine disrupters and pharmaceutically active pollutants, remains poorly characterized during real wastewater treatment at full-scale ( de Godos et al., 2012;HijosaValsero et al., 2010;Matamoros et al., 2015Matamoros et al., , 2016). ...
Article
This study investigated the removal of antibiotic ciprofloxacin during the treatment of real wastewater using high rate algal ponds (HRAP). When spiked at 2 mg/L into primary domestic wastewater, ciprofloxacin (CPX) was efficiently removed from laboratory scale photobioreactors continuously operated under various durations of artificial illumination and hydraulic residence times. Subsequent batch tests conducted with reactor microcosms showed CPX removal was mainly caused by photodegradation during daytime, and sorption to biomass during night time. These findings were confirmed during an experiment conducted in a 1000 L pilot HRAP operated outdoors, as well as during outdoor batch assays conducted using pilot HRAP microcosms. While these results highlight a potentially interesting treatment capacity in comparison to conventional biological treatment, further research must confirm these findings at relevant pollutant concentration (ng-μg/L) and determine the fate and potential toxicity of degradation products.
... In vertebrates like tadpoles and rats, TBBPA was found to be rapidly transformed to hydrophilic sulfate and glucuronide conjugates (Bernal, 2007;Fini et al., 2012), which are easily excreted to decrease the toxicity of TBBPA. In addition, microbial degradation of TBBPA in pure culture or in environmental samples involves the debromination, methylation, and oxidative cleavage of TBBPA Chang et al., 2012;Gerecke et al., 2006;Li et al., 2016a;Peng et al., 2014). These debrominated and methylated metabolites differ in their bioaccumulation potential and toxicity in different aquatic organisms like zebrafish, algae, and micro-invertebrates (McCormick et al., 2010;Debenest et al., 2010), indicating various tolerance and detoxification mechanisms in different types of organisms. ...
Article
The mechanisms underlying the bioaccumulation and detoxification of tetrabromobisphenol A (TBBPA) by terrestrial invertebrates are poorly understood. We used uniformly ring-14C-labelled TBBPA to investigate the bioaccumulation kinetics, metabolites distribution, and subsequent detoxification strategy of TBBPA in the geophagous earthworm Metaphire guillelmi in soil. The modeling of bioaccumulation kinetics showed a higher biota-soil-accumulation-factor of total 14C than that of the parent compound TBBPA, indicating that most of the ingested TBBPA was transformed into metabolites or sequestered as bound residues in the earthworms. Bound-residue formation in the digestive tract may hinder the accumulation of TBBPA in other parts of the body. Nonetheless, via the circulatory system, TBBPA was transferred to other tissues, especially the clitellum region, where sensitive organs are located. In the clitellum region, TBBPA was quickly transformed to less toxic dimethyl TBBPA ether and rapidly depurated through feces. We conclude that the detoxification of TBBPA in M. guillelmi occurred via bound-residue formation in the digestive tract as well as the generation and depuration of O-methylation metabolites. Our results provided direct evidence of TBBPA detoxification in earthworms. Further researches are needed to confirm whether O-methylation coupled with depuration is a common detoxification strategy for phenolic xenobiotics in other soil organisms needs to be determined.
... Interestingly, no DM-TBBPA was found in any of the fish, SPM or surface sediment layer samples from all sites, albeit it is considered the endpoint of environmental TBBPA by means of microbial O-methylation [17]. However, corresponding to our findings, Peng et al. [34] only found MM-TBBPA as a result of freshwater algae metabolism along with some other metabolites, but no DM-TBBPA. The literature data for DM-TBBPA are very scarce, especially for environmental monitoring data. ...
Article
Full-text available
An analytical method was developed for the determination of tetrabromobisphenol A (TBBPA), 3,3′,5,5′-tetrabromobisphenol-A-monomethyl ether (MM-TBBPA) and 3,3′,5,5′-tetrabromobisphenol-A-dimethyl ether (DM-TBBPA), and its valid application on fish muscle matrix (bream and sole), suspended particulate matter (SPM) and surface sediment layer samples, using only 0.5 g sample material, is demonstrated. Here, for the first time, DM-TBBPA could be determined by an LC-MS/MS-based method applying atmospheric pressure photoionization (APPI), using the same sample extracts for all three analytes. Samplings covered freshwater fish (bream; annually, period 2007–2013) and SPM or sediment (every second year in the period 2008–2014) at selected European sites (rivers: Tees/UK, Mersey/UK, Western Scheldt/NL, Götaälv/SE, Rhône/FR; Lake Belau/DE). TBBPA could be quantified in 13 of 36 bream samples (range about 0.5–1.2 μg kg⁻¹ ww) and 7 of 7 sole muscle samples (range about 0.5–0.7 μg kg⁻¹ ww). Further, it could be quantified in 11 of the 14 SPM samples (range about 0.5–9.4 μg kg⁻¹ dw) and in both of the surface sediment layer samples (2.3–2.6 μg kg⁻¹ dw). MM-TBBPA could be quantified in 12 of 36 bream and 4 of 7 sole muscle samples (range about 0.8–1.8 μg kg⁻¹ ww). Further, it could be quantified in 10 of the 14 river SPM samples (range about 2.3–4.5 μg kg⁻¹ dw) and in both lake surface sediment layer samples (5.2–5.5 μg kg⁻¹ dw). DM-TBBPA was rarely detectable and could not be quantified above the limit of quantification in any sample. Electronic supplementary material The online version of this article (doi:10.1007/s00216-017-0312-z) contains supplementary material, which is available to authorized users.
... These include (1) Matamoros et al. (2015), who looked at the removal of BPA in addition to 25 other CEC from wastewater in a pilot-scale HRAP, and (2) Vassalle et al. (2020), who investigated the removal of BPA and ten other CEC in the aqueous phase of a pilot-scale HRAP. Several groups have investigated the removal of BPA at the laboratory scale in artificial media, spiked with concentrations ranging from 1 to 50 mg/L (Eio et al., 2015;Gattullo et al., 2012;Guo et al., 2017;Ji et al., 2014;Li et al., 2009) However, only three laboratory-scale studies have looked at using microalgae to investigate the removal of BPA alternatives, i.e., BPAF, 4,4 0 -BPF and tetrabromobisphenol A (Peng et al., 2009(Peng et al., , 2014Sol e and Matamoros, 2016), indicating a lack of knowledge about BPA alternatives. ...
Article
Full-text available
High rate algal ponds (HRAP) are an alternative to conventional wastewater treatment with the potential for wastewater and biomass reuse. In this study, we report the development and validation of methods for analysing 18 bisphenols (BPs) in the aqueous and biomass phase of HRAP. For aqueous phase samples, obtained LLOQ ranged from 10 to 30 ng/L, and recoveries from 78% to 106%. The relative expanded uncertainty was highest at the lowest spiking level (100 ng/L) and ranged from 27% to 66% (BPA), while for the biomass, the LLOQ ranged from 25 to 75 ng/g dw, recoveries from 84% to 103%. The uncertainty ranged from 16% to 37% (BPA). On average, the influent contained 329, 144, and 21 ng/L of BPA, BPS and 4,4’-BPF, and the effluent 69 ng/L, 94 ng/L and <LLOQ, respectively. Only BPA was quantified in the algal biomass. The average removal of BPA was 80%, whereas the removal efficiency of BPS was 32%. To our knowledge, this is the first study analysing a wide range of BPs in both aqueous and biomass phase of HRAP treating real wastewater.
... Therefore, several plants were tested in that aspect, such as fungi (Trametes, Pleurotus, Bjerkandera and Dichomitus) [351], rice cell suspension [352], microalgae [353], maize [354], pumpkin [355], soybean [356], mangrove plants [357] or Annelids, Brassicaceae and Fabaceae [358]. Among these, fungi seemed the most promising due to the existence of efficient enzymes (e.g. ...
Chapter
In the past half-century, scientists were mostly concerned with polychlorinated compounds (dioxins, polychlorinated biphenyls (PCBs), etc.). But in the last decades, polybrominated compounds [especially polybrominated diphenyl ethers (PBDE) present in various materials as flame retardants] became more and more present in the environment, causing a new set of problems, and subsequently challenges. Therefore researchers focused on PBDE degradation processes, one of them being the microbiological one. However, there are other brominated compounds polluting the environment (e.g., hexabromocyclododecane, tetrabromobisphenol A, etc.) that suffer similar or different fates during various biota processes (photodegradation, phytoremediation, or microbiological decontamination). We are making a short literature screening of these naturally occurring processes destined to remove such an alternative threat.
... The collected C. vulgaris was inoculated at 10% v/v in 500 mL of Erlenmeyer flask and preserved in the 200 mL of BG11 medium. BG11 which contains the chemicals such as MgSO 4 ⋅7H 2 O (0.075 g/L), CaCl 2 ⋅2H 2 O (0.036 g/L), citric acid (0.006 g/L), Ferric ammonium citrate (0.006 g/L), and K2HPO4 (0.049 g/L) [37,38]. The pH of the basal medium was maintained 7.0 using the HCl solution. ...
Article
The current investigation highlighted the capability of the Chlorella vulgaris growth in the artificial wastewater with different concentration of NaCl incorporated with difference concentration of nanoparticle ZnO and Fe2O3. Chlorella vulgaris cultured with ZnO and Fe2O3 at the concentration of 5 mg/L, 10 mg/L, 20 mg/L and 50 mg/L. The characterization of the nanoparticles was performed through analytical technique. This study found that, the nutrient removal was effective on ZnO compared to Fe2O3 against total nitrogen and total phosphorous. Further, the NaCl concentration in the wastewater affects the growth of the microalgae and biofuel production. With regard to the biomass concentration, the 20 mg/L ZnO and 50 mg/L Fe2O3 reported highest yield of 2.08 g/L and 2.02 g/L. On the other hand, the maximum lipid accumulation of ZnO and Fe2O3 were 14.25 wt% and 13.8 wt%. Secondly, the procured lipids were processed through transesterification process and characterized by Gas chromatography mass spectrometry (GC–MS). Compelling all the above it is concluded that the Chlorella vulgaris can be the suitable candidate for treatment of wastewater and production of bio-fuel.
... BPA and four other intermediates were identified in these cultures. Biotransformation of TBBPA by freshwater algae produces a number of TBBPA metabolites, such as TBBPA sulphate, glucoside and sulphated glucoside, O-methylated TBBPA and tribromobisphenol-A [42 ]. ...
Article
Brominated flame retardants account for about 21% of the total production of flame retardants and many of these have been identified as persistent, bioaccumulative and toxic. Nevertheless, debromination of these chemicals under anaerobic conditions is well established, although this can increase their toxicity. Consequently, the production and use of these chemicals has been restricted and alternative products have been developed. Many of these are brominated compounds and share some of the disadvantages of the chemicals they are meant to replace. Therefore, other, nonbrominated, flame retardants such as organophosphorus compounds are also being used in increasing quantities, despite the fact that knowledge of their biodegradation and environmental fate is often lacking.
... In aquatic systems, TBBPA can be biotransformed by algae via sulfation, glucosylation, O-methylation, and debromination. 21 Aerobic transformation of TBBPA in the environment reportedly proceeds via O-methylation, yielding mono-and dimethyl ethers of TBBPA (MeO-TBBPA and diMeO-TBBPA, respectively). 13,22−24 The O-methylation metabolites are strongly lipophilic and are therefore highly likely to bioaccumulate in the food chain. ...
Article
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The fates of the most commonly used brominated flame retardant, tetrabromobisphenol A (TBBPA), in wastewater treatment plants is obscure. Using a 14C-tracer, we studied TBBPA transformation in nitrifying activated sludge (NAS). During the 31-day incubation, TBBPA transformation (half-life 10.3 days) was accompanied by mineralization (17% of initial TBBPA). Twelve metabolites, including those with single benzene-ring, O-methyl TBBPA ether, and nitro-compounds, were identified. When allylthiourea was added to the sludge to completely inhibit nitrification, TBBPA transformation was significantly reduced (half-life 28.9 days), formation of the polar and single-ring metabolites stopped, but O-methylation was not significantly affected. Abiotic experiments confirmed the generation of mono- and di-nitro-brominated forms of bisphenol A in NAS by the abiotic nitration of TBBPA by nitrite, a product of ammonia-oxidizing microorganisms (AOMs). Three biotic (type II ipso-substitution, oxidative skeletal cleavage, and O-methylation) and one abiotic (nitro-debromination) pathways were proposed for TBBPA transformation in NAS. Apart from O-methylation, AOMs were involved in three other pathways. Our results are the first to provide information about the complex metabolism of TBBPA in NAS and they are consistent with a determining role for nitrifiers in TBBPA degradation, by initiating its cleavage into single-ring metabolites that are substrates for the growth of heterotrophic bacteria.
... 2,4-二溴酚暴露于 胡萝卜细胞5 d后, 糖基化的产物占到总暴露量的 侯兴旺等: 典型卤代有机污染物在植物体内的代谢过程 9.3% [39] . TBBPA在淡水微藻中也会生成与葡萄糖结合 的产物 [83] , 而在人体血液和尿液中均能检测到TBBPA 与葡萄糖醛酸结合的产物 [81,82] . 因此糖基化反应在植 物体内更倾向于利用葡萄糖, 与动物体内利用葡萄糖 醛酸有所差异 [86,87] . ...
Article
Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant (BFR) that has frequently been detected in various environmental compartments. Although TBBPA biotransformation has been observed under both aerobic and anaerobic conditions, knowledge of the detailed mechanism of direct aerobic TBBPA biodegradation still remains limited. In this study, the underlying mechanism of cometabolic degradation of TBBPA by Pseudomonas sp. fz under aerobic conditions was investigated. Two key degradation pathways (beta scission and debromination) were proposed based on triple quadrupole liquid chromatography-mass spectrometry (LC-MS) analysis. TBBPA degradation by strain fz was demonstrated to be an extracellular process associated with the low-molecular-mass component (LMMC). Moreover, LMMC was preliminarily identified as oligopeptides, mainly consisting of glycine, proline, and alanine in a 2:1:1 molar ratio. Quenching studies suggested the involvement of hydroxyl radicals (•OH) in extracellular TBBPA degradation. To the best of our knowledge, we provide the first evidence that TBBPA was degraded by a biogenic Fenton-like reaction mediated via extracellular H2O2 and Fe(II)−oligopeptide complexes by the genus Pseudomonas. This study provides a new insight into the fate and biodegradation of TBBPA and other organic pollutants in natural and artificial bioremediation environments.
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Phytoplankton constitute an important component of surface water ecosystems; however little is known about their contribution to biotransformation of organic micropollutants. To elucidate biotransformation processes, batch experiments with two cyanobacterial species (Microcystis aeruginosa, Synechococcus sp.) and one green algal species (Chlamydomonas reinhardtii) were conducted. Twenty-four micropollutants were studied, including 15 fungicides and 9 pharmaceuticals. Online solid phase extraction (SPE) coupled to liquid chromatography (LC) – high resolution tandem mass spectrometry (HRMS/MS) was used together with suspect and nontarget screening to identify transformation products (TPs). 14 TPs were identified for 9 micropollutants, formed by cytochrome P450-mediated oxidation, conjugation and methylation reactions. The observed transformation pathways included reactions likely mediated by promiscuous enzyme reactions, such as glutamate conjugation to mefenamic acid and pterin conjugation of sulfamethoxazole. For 15 compounds, including all azole fungicides tested, no TPs were identified. Environmentally relevant concentrations of chemical stressors had no influence on the transformation types and rates.
Article
Bound-residue formation is a major dissipation process of most organic xenobiotics in soil. However, both the formation and nature of bound residues of tetrabromobisphenol A (TBBPA) in soil are unclear. Using a 14C-tracer, we studied the fate of TBBPA in an oxic soil during 143 days of incubation. TBBPA dissipated with a half-life of 14.7 days; at the end of incubation, 19.6% mineralized and 66.5% formed bound residues. Eight extractable metabolites were detected, including TBBPA methyl ethers, single-ring bromophenols, and their methyl ethers. Bound residues (mostly bound to humin) rapidly formed during the first 35 days. The amount of those humin-bound residues then quickly decreased, whereas total bound residues decreased slowly. By contrast, residues bound to humic acids and fulvic acids increased continuously until a plateau was reached. Ester- and ether-linked residues accounted for 9.627.0% of total bound residues during the incubation, with ester linkages being predominant. Residues bound via ester linkages consisted of TBBPA, TBBPA monomethyl ether, and an unknown polar compound. Our results indicated that bound-residue formation is the major pathway of TBBPA dissipation in oxic soil and provide first insights into the chemical structure of the reversibly ester-linked bound residues of TBBPA and its metabolites.
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Identification of novel brominated contaminants in the environment, especially the derivatives and byproducts of brominated flame retardants (BFRs), has become a wide concern because of their adverse effects on human health. Herein, we qualitatively and quantitatively identified three byproducts of tetrabromobisphenol-S bis(2,3-dibromopropyl ether) (TBBPS-BDBPE), including TBBPS mono(allyl ether) (TBBPS-MAE), TBBPS mono(2-bromoallyl ether) (TBBPS-MBAE) and TBBPS mono(2,3-dibromopropyl ether) (TBBPS-MDBPE) as novel brominated contaminants. Meanwhile, the mass spectra and analytical method for determination of TBBPS-BDBPE byproducts were presented for the first time. The detectable concentrations (dry weight) of TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE were in the ranges 28-394 μg/g in technical TBBPS-BDBPE and 0.1-4.1 ng/g in mollusks collected from the Chinese Bohai Sea. The detection frequencies in mollusk samples were 5%, 39%, 95% for TBBPS-MAE, TBBPS-MBAE and TBBPS-MDBPE, respectively, indicating their prevailing in the environment. The results showed that they could be co-produced and leaked into the environment with production process, and might be more bioaccumulative and toxic than TBBPS-BDBPE. Therefore, the production and use of TBBPS derivatives lead to unexpected contamination to the surrounding environment. This study also provided an effective approach for identification of novel contaminants in the environment with synthesized standards and Orbitrap high resolution mass spectrometry.
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A NiO/Co 3 O 4 /g-C 3 N 4 nanocomposite was prepared by one step thermal decomposition and it exhibited excellent photoelectrochemical activity for sensing TBBP-A.
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A rapid and sensitive method was developed for the identification and quantitation of tetrabromobisphenol A (TBBPA) derivatives in water samples. Six major TBBPA derivatives, including tetrabromobisphenol A bis(2-hydroxyethyl) ether (TBBPA-BHEE), tetrabromobisphenol A bis(glycidyl) ether (TBBPA-BGE), tetrabromobisphenol A bis(allyl) ether (TBBPA-BAE), tetrabromobisphenol A mono(2-hydroxyethyl) ether (TBBPA-MHEE), tetrabromobisphenol A mono(glycidyl) ether (TBBPA-MGE) and tetrabromobisphenol A mono(allyl) ether (TBBPA-MAE), were selected as the target compounds. By applying the silver cation (Ag+) as the post-column derivatization reagent, the TBBPA derivatives formed complexes ([M + Ag]NO3) online, which could be effectively electrosprayed to generate ionic clusters ([M + Ag]+) for sensitive mass analysis. Under the optimized conditions, the 6 TBBPA derivatives were separated and detected within 10 min. The limits of detection (LODs) were between 0.16 and 1.96 [small mu ]g L-1, and the linear ranges extended to 200 [small mu ]g L-1 (R2 [greater-than-or-equal] 0.9957). The relative standard deviations (RSDs) were less than 7.7% for 10 [small mu ]g L-1 of the TBBPA derivatives (n = 7). The proposed method was successfully applied in analysis of environmental water samples. The spiked recoveries ranged from 81.3% to 114.9%, suggesting the accuracy and feasibility of the method.
Article
Tetrabromobisphenol A (TBBPA), as well as its alternatives Tetrabromobisphenol S (TBBPS) and Tetrachlorobisphenol A (TCBPA), are widely used halogenated flame retardants. Their high detection rates in human breast milk and umbilical cord serum have raised wide concerns about their adverse effects on human fetal development. In this study, we evaluated the cytotoxicity and neural developmental toxicity of TBBPA, TBBPS and TCBPA with a mouse embryonic stem cell (mESC) system, at human body fluid and environmental relevant doses. All the three compounds showed similar trends in their cytotoxic effects. However, while TBBPA and TBBPS stimulated ESC neural differentiation, TCBPA significantly inhibited neurogenesis. Mechanistically, we demonstrated that, as far as the NOTCH (positive regulator) and WNT (negative regulator) pathways were concerned, TBBPA only partially and slightly disturbed them, whereas TBBPS significantly inhibited the WNT pathway, and TCBPA down-regulated the expression of NOTCH effectors but increased the WNT signaling, actions which both inhibited neural specification. In conclusion, our findings suggest that TBBPS and TCBPA may not be safe alternatives to TBBPA, and their toxicity need to be comprehensively evaluated.
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Due to the extensive commercial use of brominated flame retardants (BFRs), human beings are chronically exposed to BFRs, causing great harms to human health, which imposes urgent demands to degrade them in the environment. Among various degradation techniques, catalytic degradation has been proven to be outstanding because of its rapidness and effectiveness. Therefore, much attention has been given to catalytic degradation, especially the extensively studied photocatalytic degradation and nanocatalytic reduction techniques. Recently, some novel advanced catalytic techniques have been developed and show excellent catalytic degradation efficiency for BFRs, including natural substances catalytic degradation, new Fenton catalytic degradation, new chemical reagent catalytic degradation, new material catalytic degradation, electrocatalytic degradation, plasma catalytic degradation, and composite catalytic degradation systems. In addition to the common features of traditional catalytic techniques, these novel techniques possess their own specific advantages in various aspects. Therefore, this review summarized the degradation mechanism of BFRs by the above new catalytic degradation methods under the laboratory conditions, simulated real environment, and real environment conditions, and further evaluated their advantages and disadvantages, aiming to provide some research ideas for the catalytic degradation of BFRs in the environment in the future. We suggested that more attention should focus on features of novel catalytic techniques, including eco-friendliness, cost-effectiveness, and pragmatic usefulness.
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Although the abiotic and biotic transformation/degradation (T/D) processes of tetrabromobisphenol A (TBBPA) have been widely investigated in model experiments, few reviews have focused on these processes along with their metabolites or degradation products. In this paper, we summarize the current knowledge on the T/D of TBBPA and its derivatives, including abiotic and biotic T/D strategies/conditions, mechanisms, metabolites and environmental occurrences. Various treatments, such as pyrolysis, photolysis, chemical reactions and biotransformation, have been employed to study the metabolic mechanism of TBBPA and its derivatives and to remediate associated contaminated environments. To date, more than 100 degradation products and metabolites have been identified, dominated by less brominated compounds such as bisphenol A, 2,6-dibromo-4-isopropylphenol, 2,6-dibromo-4-hydroxyl-phenol, 2,6-dibromophenol, isopropylene-2,6-dibromophenol, 4-(2-hydroxyisopropyl)-2,6-dibromophenol, etc. It can be concluded that the T/D of TBBPA mainly takes place through debromination and β-scission. In some environmental media and human and animal tissues, brominated metabolites, glucoside and sulfate derivatives are also important T/D products. Here, the T/D products of TBBPA and its derivatives have been most comprehensively presented from the literature in recent 20 years. This review will enhance the understanding of the environmental behaviors of TBBPA-associated brominated flame retardants along with their ecological and health risks.
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Short chain and medium chain chlorinated paraffins (SCCPs and MCCPs) are mixtures of complex chemical compounds with intensive usage. They are frequently detected in various environmental samples. However, the interaction between CPs and plants, especially the biotransformation behaviors of CPs within plants are poorly understood. In this study, 1,2,5,6,9,10-hexachlorodecane (CP-4, a typical standard of individual SCCP congeners) and 52%-MCCP (a commercial mixture standard of MCCPs with 52% chlorine content by mass) were selected as representative chemicals to explore the metabolic behaviors of SCCPs and MCCPs using suspension rice cell culture exposure systems. 79.53% and 40.70% of CP-4 and 52%-MCCP were metabolized by suspension rice cells, respectively. A complementary suspected screening strategy based on the pair mass distances (PMD) analysis algorithm was used to study the metabolism of CPs mediated by the plant cells. Forty and twenty-five metabolic products for CP-4 and 52%-MCCP were identified, including (multi-) hydroxylation, dechlorination, -HCl- elimination metabolites, (hydroxylation-) sulfation and glycosylation conjugates. Here we propose a comprehensive metabolic molecular network and provide insight on degradation pathways of SCCPs and MCCPs in plants for the first time, aiding in further understanding of the transformation behaviors of CPs.
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Tetrabromobisphenol A (TBBPA) is a new type of persistent organic pollutant, which causes environmental pollution and health problems, and has attracted the attention of the international research community. Once released into the environment, TBBPA can interact with dissolved organic matter (DOM), which affects its behavior. However, the effect of DOM on the biological toxicity of TBBPA remains unclear. The toxic effects of TBBPA on three model aquatic organisms (Chlorella pyrenoidosa, Daphnia magna, and Danio rerio), in the absence and presence of DOM were investigated. The order of acute toxicity of TBBPA to the three aquatic organisms was D. magna > D. rerio > C. pyrenoidosa. In the presence of DOM the median effect/lethal concentrations values of TBBPA to the three aquatic organisms decreased by at least 32 (C. pyrenoidosa), 52 (D. magna), and 6.6% (D. rerio), implying that DOM enhanced the acute toxicity of TBBPA to all the organisms. Moreover, the higher the concentration of DOM, the higher the acute toxicity of TBBPA. Furthermore, the presence of DOM increased total reactive oxygen species (ROS) induced by TBBPA in a concentration-dependent manner. A tracking analysis of total ROS in the three aquatic organisms also showed that the presence of DOM aggravated the accumulation of total ROS induced by TBBPA, indicating that oxidative stress is a characteristic mechanism of toxicity of TBBPA to aquatic organisms when DOM is present. In addition, the evaluated risk quotient indicated that the ecological risk of TBBPA to aquatic organisms can increase in environments rich in DOM.
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In this study, Aspergillus sydowii FJH-1 isolated from soil was verified to be a novel triphenyl phosphate (TPhP) degrader. Biodegradation efficiency of TPhP by Aspergillus sydowii FJH-1 exceeded 90% within 6 days under the optimal conditions (pH 4–9, 30 ℃, initial concentration less than 20 mg/L). Proteomics analysis uncovered the proteins perhaps involved in hydrolysis, hydroxylation, methylation and sulfonation of TPhP and the primary intracellular adaptive responses of Aspergillus sydowii FJH-1 to TPhP stress. The expression of carboxylic ester hydrolase along with several thioredoxin- and glutathione-dependent oxidoreductases were induced to withstand the toxicity of TPhP. The presence of TPhP also caused obvious upregulation of proteins concerned with glycolysis, pentose phosphate pathway and tricarboxylic acid cycle. Data from toxicological tests confirmed that the cytotoxicity and phytotoxicity of TPhP was effectively decreased after treatment with Aspergillus sydowii FJH-1. Additionally, bioaugmentation with Aspergillus sydowii FJH-1 was available for promoting TPhP removal in real water and water-sediment system. Collectively, the present study offered a deeper insight into the biodegradation mechanism and pathway of TPhP by a newly screened fungal strain Aspergillus sydowii FJH-1 and validated the feasibility of applying this novel degrader in the bioremediation of TPhP-polluted matrices.
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Microalgae are primary producers of most marine ecosystems, which are under the threat of emergent pollutants such as microplastics (MPs) and tetrabromobisphenol A (TBBPA). Although motility is critical for the survival and production of microalgae, the impacts of emergent pollutants on this important behavioural characteristic remain unknown. Therefore, the toxic effects of MPs and TBBPA, alone and in combination, on the motility of two microalgae, Platymonas subcordiformis and Dicrateria zhanjiangensis, were investigated in this study. In addition, the impacts of the pollutants on energy supply and oxidative stress status were also assessed to reveal potential underlying mechanisms. Our results demonstrated that the motility (both velocity and mode of swimming) of these microalgae was significantly suppressed by the pollutant tested. Further analysis indicated that microalgae exposed to pollutants had a significantly lower intracellular content of adenosine triphosphate (ATP), which may be due to the disruption of photosynthesis and glycolysis. In addition, our data showed that the pollutants tested imposed significant oxidative stress on the microalgae, which may be another reason for the decline in motility observed. Moreover, the growth of microalgae was significantly inhibited by the pollutants tested, and coexposure to TBBPA and MPs was shown to be more toxic than single exposure. Data obtained indicate waterborne MPs and TBBPA may pose significant threat to marine microalgae and subsequently the health of the marine ecosystem.
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The removal of 18 bisphenols at wastewater relevant concentrations (μg L⁻¹ range) was investigated and compared between Chlorella vulgaris cultures with pH adjusted to 6.8 and pH non-adjusted cultures where pH raised to above 10. Bisphenols with a high partition coefficient (log P > 6) partitioned to biomass soon after spiking, whereas bisphenols with a low partition coefficient (log P < 4) remained largely in the aqueous phase. Hydrophobic bisphenols and BPF isomers were removed to a large degree in pH adjusted conditions, while BPS and BPAF were the most recalcitrant. The overall average removal after 13 days was similar in both experiments, with 72 ± 2% and 73 ± 5% removed in pH non-adjusted and pH adjusted series, respectively. The removal correlated with chlorophyll a concentration for most bisphenols meaning that algae played a crucial role in their removal, while culture pH also governed the removal of some compounds.
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Organic pollutants that are introduced into the aquatic ecosystem can transform by various mechanisms. Biotransformation is an important process for predicting the remaining structures of pollutants in the ecosystem, and their toxicity. This study focused on triphenyl phosphate (TPHP), which is a commonly used organophosphate flame retardant and plasticizer. Since TPHP is particularly toxic to aquatic organisms, it is essential to understand its biotransformation in the aquatic environment. In the aquatic ecosystem, based on consideration of the producer-consumer-decomposer relationship, the biotransformation products of TPHP were identified, and their toxicity was predicted. Liquid chromatography-high resolution mass spectrometry was used for target, suspect, and non-target analysis. The obtained biotransformation products were estimated for toxicity based on the prediction model. As a result, 29 kinds of TPHP biotransformation products were identified in the aquatic ecosystem. Diphenyl phosphate was detected as a common biotransformation product through a hydrolysis reaction. In addition, products were identified by the biotransformation mechanisms of green algae, daphnid, fish, and microorganism. Most of the biotransformation products were observed to be less toxic than the parent compound due to detoxification except some products (hydroquinone, beta-lyase products, palmitoyl/stearyl conjugated products). Since various species exist in a close relationship with each other in an ecosystem, an integrated approach for not only single species but also various connected species is essential.
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The glycosylation process was investigated for the common brominated flame retardant tetrabromobisphenol A (TBBPA) in hydroponic exposure systems with pumpkin seedlings. Two typical glycosylation metabolites of TBBPA formed in pumpkin seedlings, TBBPA mono-β-d-glucopyranoside (TBBPA MG) and TBBPA di-β-d-glucopyranoside (TBBPA DG), increasing their mass early in the exposure (reaching maximum masses of 608 ± 53 and 3806 ± 1570 pmol at 12 h, respectively) and then falling throughout exposure. These two metabolites were released from roots to rhizosphere solutions, where they also exhibited initial increases followed by decreasing trends (reaching maximum masses of 595 ± 272 pmol at 3 h and 77.1 ± 36.0 pmol at 6 h, respectively). However, a (pseudo)zero-order deglycosylation of TBBPA MG and TBBPA DG (during the first 1.5 h) back to TBBPA was unexpectedly detected in the hydroponic solutions containing pumpkin exudates and microorganisms. The function of microorganisms in the solutions was further investigated, revealing that the microorganisms were main contributors to deglycosylation. Plant detoxification through glycosylation and excretion, followed by deglycosylation of metabolites back to the toxic parent compound (TBBPA) in hydroponic solutions, provides new insight into the uptake, transformation, and environmental fate of TBBPA and its glycosylated metabolites in plant/microbial systems.
Article
To better understand the uptake, biotransformation and physiological response to tetrabromobisphenol A (TBBPA) in mangrove plants, a short term 14-day hydroponic assay with two mangrove species, Avicennia marina (A. marina) and Kandelia obovata (K. obovata), was conducted. Results showed that two mangrove species could uptake, translocate and accumulate TBBPA from solution. The hydroxylation and debromination metabolites of TBBPA, including OH-TBBPA, TriBBPA, MonoBBPA, and BPA, were found in both mangroves for the first time. The high-level TBBPA suppressed the growth and increased malondialdehyde (MDA) content of K. obovata, did not pose any negative affect on A. marina. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of K. obovata significantly increased in the 7th day, whereas, SOD and POD activities at high-levels of TBBPA became comparable to the control in the 14th day. Contrastingly, the antioxidant enzymes activities of A. marina were positively stimulated by TBBPA during the 14-day of observation, indicating that A. marina was more tolerant of TBBPA.
Article
Tetrabromobisphenol A (TBBPA) and its debromination (∑BBPA) and O-methylation (∑MeO-TBBPA) products were widely detected in matched sediments, fish, and whelks samples collected from a typical electronic waste (e-waste) dismantling site in Southern China, with concentrations ranging from 19.8 to 1.52 × 10⁴, 8.05 to 1.84 × 10³, and 0.08 to 11.9 ng/g dry weight in sediments, and 6.96 to 1.97 × 10⁵, 3.84 to 7.07 × 10³, and 3.42 to 472 ng/g lipid in biotas, for TBBPA, ∑BBPA, and ∑MeO-TBBPA, respectively. Significantly higher concentrations of these targets were found in samples collected close to the e-waste site, indicating their potential e-waste sources. Tri-BBPA was the most abundant debromination products in sediments, whereas diMeO-TBBPA was the dominant O-methylation product in biotas. Relatively higher levels of diMeO-TBBPA found in liver and kidneys, suggesting these chemicals might be mainly derived from the in vivo biotransformation. Furthermore, significantly higher biota-sediment accumulation factor values were found for diMeO-TBBPA than these of TBBPA, indicating that O-methylation would increases their accumulation in aquatic organisms. Our study provides insights into the accumulation and biotransformation of TBBPA in aquatic systems. Further studies should pay attention to the occurrence as well as potential health risks of these transformation products.
Article
Tetrabromobisphenol A (TBBPA) is extensively used as brominated flame retardant. TBBPA and some of its metabolites had been identified as endocrine disrupter with potential health risk. Understanding the distribution characters of TBBPA and its metabolites in fish is essential to evaluate the potential impacts of TBBPA on aqueous ecosystem. This study developed a simple method to identify and quantify TBBPA and its metabolites simultaneously in tissues of alult zebrafish by ultra-high performance liquid chromatography couple with Orbitrap high resolution mass spectrometry(UHPLC-Orbitrap-HRMS). Six TBBPA metabolites were identified in liver, kidney, gill and muscle of adult zebrafish exposed to water containing different TBBPA levels, two of them, 1,3-dibromo-2‑methoxy‑5-vinylbenzene and 2,6-dibromo-4-nitrophenol were first detected. TBBPA and its metabolites were mainly distributed in the livers and kidneys of zebrafish. The levels of TBBPA and metabolites reached maximum on exposed day 3, then decreased gradually in liver and kidney. TBBPA oxidative cleavage products and TBBPA-monosulfate were the dominant metabolites. UHPLC-Orbitrap-HRMS provided an effective solution to study the distribution and metabolite characters of TBBPA in aquatic organisms.
Article
As a persistent organic pollutant, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) has been widely detected in aquatic environments. However, studies on the fate and transfer of BDE-47 in the aquatic food chain remain scarce. In this study, we investigated the bioaccumulation and elimination of BDE-47 in Chlorella pyrenoidosa, as well as the trophic transfer and biomagnification of BDE-47 in the "C. pyrenoidosa-Daphnia magna" food chain, using C-14 radioactive tracer technology. After 96 h of BDE-47 exposure, the algae accumulated 88.98% ± 0.59% of the initial radioactivity from the medium, and 36.09% ± 9.22% of the accumulated residues in the algae occurred in the form of bound residues. During 96 h of elimination, only 13% ± 0.50% of accumulated radioactivity in the algae was released into the medium. After 24 h of exposure, D. magna accumulated 35.99% ± 2.55% of the initial radioactivity via water filtration from the medium, and 31.35% ± 1.92% of the accumulated radioactivity in D. magna occurred as bound residues. However, D. magna accumulated 66.89% ± 2.37% of the accumulated radioactivity in the algae via food uptake from the contaminated algae, with a high portion of radioactivity observed as bound residues (83.40% ± 0.97% of accumulated radioactivity in D. magna). This indicated a reduction in the environmental risk of BDE-47. There was obvious biomagnification in the food chain between C. pyrenoidosa and D. magna (biomagnification factors, BMFs>1), resulting in environmental hazard transfer in the aquatic food chain. However, no metabolite was found during the exposure experiment, and further studies should be carried out to investigate the intrinsic mechanisms of the trophic transfer of BDE-47, especially in multilevel food chains. Therefore, this study elucidated the effect of dietary uptake on the bioaccumulation of BDE-47 in D. magna and provided new insight for future analysis regarding the bioaccumulation and biomagnification of organic pollutants in the food chain.
Article
The increase levels of tetrabromobisphenol A (TBBPA) in mangrove wetlands is of concern due to its potential toxic impacts on ecosystem. A 93-day greenhouse pot experiment was conducted to investigate the effects of mangrove plants, A. marina and K. obovata, on TBBPA degradation in sediment and to reveal the associated contributing factor(s) for its degradation. Results show that both mangrove species could uptake, translocate, and accumulate TBBPA from mangrove sediments. Compared to the unplanted sediment, urease and dehydrogenase activity as well as total bacterial abundance increased significantly (p < 0.05) in the sediment planted with mangrove plants, especially for K. obovata. In the mangrove-planted sediment, the Anaerolineae genus was the dominant bacteria, which has been reported to enhance TBBPA dissipation, and its abundance increased significantly in the sediment at early stage (0-35 day) of the greenhouse experiment. Compared to A. marina-planted sediment, higher enrichment of Geobater, Pseudomonas, Flavobacterium, Azoarcus, all of which could stimulate TBBPA degradation, was observed for the K. obovata-planted sediment during the 93-day growth period. Our mass balance result has suggested that plant-induced TBBPA degradation in the mangrove sediment is largely due to elevated microbial activities and total bacterial abundance in the rhizosphere, rather than plant uptake. In addition, different TBBPA removal efficiencies were observed in the sediments planted with different mangrove species. This study has demonstrated that K. obovata is a more suitable mangrove species than A. marina when used for remediation of TBBPA-contaminated sediment.
Article
The atmosphere occurrence of the most frequency used halogenated flame retardants (HFRs), including “old” chemicals such as polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A, hexabromocyclododecanes, and “new” chemicals such as decabromodiphenyl ethane, dechlorane plus, and short-chain chlorinated paraffins (SCCPs) were mainly reviewed. From data collected, these chemicals have reached all corners of the globe, and the atmospheric concentrations of HFRs were closely associated with production and usage of commercial products. The highest air concentrations of HFRs were measured at industrial and urban area with higher population density. The levels of “old” HFRs are decreasing or leveling off, while the “new” groups continue to grow. In addition, a large number of potential transformation products were also tentatively discovered and a few were structurally identified in both atmosphere and biota. Dehalogenation appears to be the most important atmospheric degradation processes. While, in animals and human body, the hydroxylated metabolites are of significant concern due to enhanced toxicological effects. However, due to limited availability of authentic standards, only a few compounds, such as hydroxylated PBDEs have been identified in the atmospheric environments and biota. Further studies are needed to elucidate possible transformation pathways and to enhance the monitoring of transformation products.
Article
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant in the world. Its biotic methylation products, tetrabromobisphenol A mono- and di- methyl ether (TBBPA MME and TBBPA DME) are frequently detected in the environment. But the importance of abiotic methylation reactions of TBBPA in the environment is not known. In this study, the methylation of TBBPA mediated by methyl iodide (CH3I), a ubiquitous compound in aqueous environments, was investigated in simulated waters in the laboratory. It was found that abiotic methylation occurred under both light and dark conditions and was largely affected by the pH, temperature and the natural organic matter (NOM) concentration of the water. Abiotic methylation was further verified in natural river water, and the yield of TBBPA MME mediated abiotically by CH3I was much greater than biotic methylation. According to our calculations and by comparison of the activation energies (Ea) for the abiotic methylation of TBBPA and the other four typical phenolic contaminants/metabolites (bisphenol A (BPA), triclosan (TCS), 5-OH-BDE-47 and 4’-OH-CB-61) mediated by CH3I, those phenolic compounds all show great methylation potentials. Results indicate a new abiotic pathway to generate TBBPA MME and TBBPA DME from TBBPA, and they also confirm the potentials for abiotic methylation of other phenolic contaminants in aqueous environment.
Article
Emerging contaminants (ECs) are primarily synthetic organic chemicals that have a focus of increasing attention due to either increased awareness of their potential risks to humans and aquatic biota, or only recently been detected in the aquatic environment or drinking water supplies, through improved analytical techniques. . Many ECs have no regulatory standards due to the lack of information on the effects of chronic exposure. Pharmaceuticals, personal care products, pesticides and flame retardants are some of the most frequently detected ECs in aquatic environments, with over 200 individual compounds identified, to date. Current wastewater treatment is ineffective at removing ECs and there is a vital need for the development of efficient, cost-effective EC treatment systems that can be applied to a range of scales and wastewater types. Microalgae have demonstrated potential for detoxifying organic and inorganic pollutants, with a number of large-scale wastewater treatment microalgal technologies already developed. There are three main pathways that microalgae can bioremediate ECs; bioadsorption, bio-uptake and biodegradation. Microalgal bioadsorption occurs when ECs are either adsorbed to cell wall components, or onto organic substances excreted by the cells, while bio-uptake involves the active transport of the contaminant into the cell, where it binds to intracellular proteins and other compounds. Microalgal biodegradation of ECs involves the transformation of complex compounds into simpler breakdown molecules through catalytic metabolic degradation. Biodegradation provides one of the most promising technologies for the remediation of contaminants of concern as it can transform the contaminant to less toxic compounds rather than act as a biofilter. Further research is needed to exploit microalgal species for EC bioremediation properties, such as increased bioadsorption, enhanced biodegrading enzymes and optimised growth conditions. When coupled with nutrient removal, microalgal treatment of EC can be a cost-effective viable option for the reduction of contaminant pollution in waterways.
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The coastal environments worldwide are subjected to increasing TBBPA contamination, but current knowledge on aerobic biodegradability of this compound by marine microbes is lacking. The aerobic removal of TBBPA using marine consortia under eight different cometabolic conditions was investigated here. Results showed that the composition and diversity of the TBBPA-degrading consortia had diverged after 120-day incubation. Pseudoalteromonas, Alteromonas, Glaciecola, Thalassomonas, and Limnobacter were the dominant genera in enrichment cultures. Furthermore, a combination of beef extract- and peptone-enriched marine consortia exhibited higher TBBPA removal efficiency (approximately 60%) than the other substrate amendments. Additionally, Alteromonas macleodii strain GCW was isolated from a culture of TBBPA-degrading consortium. This strain exhibited about 90% of degradation efficiency toward TBBPA (10 mg L−1) after 10 days of incubation under aerobic cometabolic conditions. The intermediates in the degradation of TBBPA by A. macleodii strain GCW were analyzed and the degradation pathways were proposed, involving β-scission, debromination, and nitration routes.
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Tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) were determined in water, sediments, sediment cores, and three fish species from a river running through a highly industrialized area in South China. TBBPA concentrations exceeded those of HBCDs in the sediment and the dissolved phase of water and its levels in fish were at the high end of worldwide figures. 26% of HBCDs and 99% of TBBPA were found in dissolved phase of water. Plecostomus occupying high trophic level exhibited higher HBCD levels and higher abundance of α-HBCD than mud carp and nile tilapia which occupy low trophic level. An enrichment of (+)-α-HBCD in three fish species but (-)-α-HBCD in sediment was observed. As for γ-HBCD, most of sediment exhibited racemic while a species-dependence in fish sample was found. No clear trend was found for vertical distribution of enantiomeric profile for γ-HBCD, suggesting that the enantioselectivity of degradation of γ-HBCD is limited.
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The objective of this study was to determine the removal of zinc and copper by two freshwater green microalgae Chlorella pyrenoidosa and Scenedesmus obliquus and to investigate changes of algal ultrastructure and photosynthetic pigment. Algal cells were exposed for 8 days to different initial zinc or copper concentrations. Heavy metal concentrations were detected by an atomic absorption spectrophotometer. Algal growth, ultrastructure, and photosynthetic pigment were analyzed by a microplate reader, transmission electron microscope, and spectrophotometer, respectively. Low zinc and copper concentrations induced increase in algal growth, whereas application of high zinc and copper concentrations suppressed the growth of both algae. High metal concentrations also decreased the photosynthetic pigments and destroyed algal cell ultrastructure. The zinc removal efficiency by both algae increased rapidly during the first day and thereafter remained nearly constant throughout the experiment. The copper removal efficiency by both algae increased slowly during the whole experimental periods. In all cultures, the quantity of both metals removed intracellularly was much lower than the adsorbed quantity on the cell surface. Both strains of the microalgae had proven effective in removing zinc and copper from aqueous solutions, with the highest removal efficiency being near 100%. In addition, C. pyrenoidosa appeared to be more efficient than S. obliquus for removing copper ions. On the contrary, S. obliquus appeared to be more efficient than C. pyrenoidosa for removing zinc ions.
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The photoassisted degradation (HPLC-UV absorption), dehalogenation (HPLC-IC) and mineralization (TOC decay) of the flame retardants tetrabromobisphenol-A (TBBPA) and tetrachlorobisphenol-A (TCBPA) were examined in UV-irradiated alkaline aqueous TiO2 dispersions (pH 12), and for comparison the parent bisphenol-A (BPA, an endocrine disruptor) in pH 4-12 aqueous media to assess which factor impact most on the photodegradative process. Complete degradation (2.7-2.8 x 10(-2) min(-1)) and dehalogenation (1.8 x 10(-2) min(-1)) of TBBPA and TCBPA occurred within 2 h of UV irradiation, whereas only 45-60% mineralization (2.3-2.7 x 10(-3) min(-1)) was complete within 5 h for the flame retardants at pH 12 and ca. 80% for the parent BPA. Factors examined in the pH range 4-12 that impact the degradation of BPA were the point of zero charge of TiO2 particles (pH(pzc): electrophoretic method), particle or aggregate sizes of TiO2 (light scattering), and the relative number of(center dot)H radicals(as DMPO-(OH)-O-cente
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Two strains of bacteria capable of carrying out the O-methylation of phenolic compounds, one from the gram-positive genus Rhodococcus and one from the gram-negative genus Acinetobacter, were used to examine the O-methylation of phenols carrying fluoro-, chloro-, and bromo-substituents. Zero-order rates of O-methylation were calculated from data for the chloro- and bromophenols; there was no simple relationship between the rates of reaction and the structure of the substrates, and significant differences were observed in the responses of the two test organisms. For the gram-negative strain, the pattern of substitution was as important as the number of substituents. Hexachlorophene was resistant to O-methylation by both strains, and tetrabromobisphenol-A was O-methylated only by the gram-positive strain. It is suggested that in the natural environment, bacterial O-methylation of phenols carrying electron-attracting substituents might be a significant alternative to biodegradation.
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Tetrabromobisphenol A (TBBPA) is a flame retardant that is used as an additive during manufacturing of plastic polymers and electronic circuit boards. Little is known about the fate of this compound in the environment. In the current study we investigated biodegradation of TBBPA, as well as 2,4,6-tribromophenol (TBP), in slurry of anaerobic sediment from a wet ephemeral desert stream bed contaminated with chemical industry waste. Anaerobic incubation of the sediment with TBBPA and peptone-tryptone-glucose-yeast extract medium resulted in a 80% decrease in the TBBPA concentration and accumulation of a single metabolite. This metabolite was identified by gas chromatography-mass spectrometry (GC-MS) as nonbrominated bisphenol A (BPA). On the other hand, TBP was reductively dehalogenated to phenol, which was further metabolized under anaerobic conditions. BPA persisted in the anaerobic slurry but was degraded aerobically. A gram-negative bacterium (strain WH1) was isolated from the contaminated soil, and under aerobic conditions this organism could use BPA as a sole carbon and energy source. During degradation of BPA two metabolites were detected in the culture medium, and these metabolites were identified by GC-MS and high-performance liquid chromatography as 4-hydroxybenzoic acid and 4-hydroxyacetophenone. Both of those compounds were utilized by WH1 as carbon and energy sources. Our findings demonstrate that it may be possible to use a sequential anaerobic-aerobic process to completely degrade TBBPA in contaminated soils.
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Brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), pentabromophenol (PBP), and tetrabromobisphenol A (TBBPA) are produced in large quantities for use in electronic equipment, plastics, and building materials. Because these compounds have some structural resemblance to the thyroid hormone thyroxine (T(4)), it was suggested that they may interfere with thyroid hormone metabolism and transport, e.g., by competition with T(4) on transthyretin (TTR). In the present study, we investigated the possible interaction of several brominated flame retardants with T(4) binding to TTR in an in vitro competitive binding assay, using human TTR and 125 I-T(4) as the displaceable radioligand. Compounds were tested in at least eight different concentrations ranging from 1.95 to 500 nM. In addition, we investigated the structural requirements of these and related ligands for competitive binding to TTR. We were able to show very potent competition binding for TBBPA and PBP (10.6- and 7.1-fold stronger than the natural ligand T(4), respectively). PBDEs were able to compete with T(4)-TTR binding only after metabolic conversion by induced rat liver microsomes, suggesting an important role for hydroxylation. Brominated bisphenols with a high degree of bromination appeared to be more efficient competitors, whereas chlorinated bisphenols were less potent compared to their brominated analogues. These results indicate that brominated flame retardants, especially the brominated phenols and tetrabromobisphenol A, are very potent competitors for T(4) binding to human transthyretin in vitro and may have effects on thyroid hormone homeostasis in vivo comparable to the thyroid-disrupting effects of PCBs.
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Tetrabromobisphenol A (TBBPA) is widely used as a flame retardant and is suspected to be stable in the environment with possible widespread human exposures. This study reports the characterization of the toxicokinetics of TBBPA in human subjects and in rats. A single oral dose of 0.1 mg/kg TBBPA was administered to five human subjects. Rats were administered a single oral dose of 300 mg TBBPA/kg body weight. Urine and blood concentrations of TBBPA and its metabolites were determined by LC/MS-MS. TBBPA-glucuronide and TBBPA-sulfate were identified as metabolites of TBBPA in blood and urine of the human subjects and rats. In blood, TBBPA-glucuronide was detected in all human subjects, whereas TBBPA-sulfate was only present in blood from two individuals. Maximum plasma concentrations of TBBPA-glucuronide (16 nmol/l) were obtained within 4 h after administration. In two individuals where TBBPA-sulfate was present in blood, maximum concentrations were obtained at the 4-h sampling point; the concentrations rapidly declined to reach the limit of detection (LOD) after 8 h. Parent TBBPA was not present in detectable concentrations in any of the human plasma samples. TBBPA-glucuronide was slowly eliminated in urine to reach the LOD 124 h after administration. In rats, TBBPA-glucuronide and TBBPA-sulfate were also the major metabolites of TBBPA present in blood; in addition, a diglucuronide of TBBPA, a mixed glucuronide-sulfate conjugate of TBBPA, tribromobisphenol A, and the glucuronide of tribromobisphenol A were also present in low concentrations. TBBPA plasma concentrations peaked at 103 micromol/l 3 h after administration and thereafter declined with a half-life of 13 h; maximal concentrations of TBBPA-glucuronide (25 micromol/l) were also observed 3 h after administration. Peak plasma concentrations of TBBPA-sulfate (694 micromol/l) were reached within 6 h after administration. The obtained results suggest absorption of TBBPA from the gastrointestinal tract and rapid metabolism of the absorbed TBBPA by conjugation resulting in a low systemic bioavailability of TBBPA.
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Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently, concern for this emerging class of chemicals has risen because of the occurrence of several classes of BFRs in the environment and in human biota. The widespread production and use of BFRs; strong evidence of increasing contamination of the environment, wildlife, and people; and limited knowledge of potential effects heighten the importance of identifying emerging issues associated with the use of BFRs. In this article, we briefly review scientific issues associated with the use of tetrabromobisphenol A, hexabromocyclododecane, and three commercial mixtures of polybrominated diphenyl ethers and discuss data gaps. Overall, the toxicology database is very limited; the current literature is incomplete and often conflicting. Available data, however, raise concern over the use of certain classes of brominated flame retardants.
Article
Considerable progress has been made in the last few years in understanding the mechanisms of microbial degradation of halogenated aromatic compounds. Much is already known about the degradation mechanisms under aerobic conditions, and metabolism under anaerobiosis has lately received increasing attention. The removal of the halogen substituent is a key step in degradation of halogenated aromatics. This may occur as an initial step via reductive, hydrolytic or oxygenolytic mechanisms, or after cleavage of the aromatic ring at a later stage of metabolism. In addition to degradation, several biotransformation reactions, such as methylation and polymerization, may take place and produce more toxic or recalcitrant metabolites. Studies with pure bacterial and fungal cultures have given detailed information on the biodegradation pathways of several halogenated aromatic compounds. Several of the key enzymes have been purified or studied in cell extracts, and there is an increasing understanding of the organization and regulation of the genes involved in haloaromatic degradation. This review will focus on the biodegradation and biotransformation pathways that have been established for halogenated phenols, phenoxyalkanoic acids, benzoic acids, benzenes, anilines and structurally related halogenated aromatic pesticides. There is a growing interest in developing microbiological methods for clean-up of soil and water contaminated with halogenated aromatic compounds.
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The contamination of the environment with tetrabromobisphenol-A (TBBPA), an endocrine disruptor, is a concern. We examined anaerobic degradation of TBBPA in sediment samples from the Erren River in southern Taiwan. Anaerobic degradation of TBBPA was enhanced with the addition of humic acid (0.5 g L−1), sodium chloride (1 mass/vol%), zero-valent iron (1 g L−1), vitamin B12 (0.025 mg L−1), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L−1), or surfactin (43 mg L−1) but was inhibited by the addition of acetate (30 mM), lactate (20 mM), or pyruvate (20 mM). Sulfate-reducing bacteria, methanogen, and eubacteria are involved in the anaerobic degradation of TBBPA; sulfate-reducing bacteria is a major component of the sediment.
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Summary A new polybrominated diphenyl ether (1) has been isolated from the green algaCladaphora fascicularis, and the structure was determined by spectral analysis and conversion to known compounds. It showed antibacterial and antiinflammatory activities.
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On the basis of a comparative study of 178 strains of cyanobacteria, representative of this group of prokaryotes, revised definitions of many genera are proposed. Revisions are designed to permit the generic identification of cultures, often difficult through use of the field-based system of phycological classification. The differential characters proposed are both constant and readily determinable in cultured material. The 22 genera recognized are placed in five sections, each distinguished by a particular pattern of structure and development. Generic descriptions are accompanied by strain histories, brief accounts of strain properties, and illustrations; one or more reference strains are proposed for each genus. The collection on which this analysis was based has been deposited in the American Type Culture Collection, where strains will be listed under the generic designations proposed here.
Article
Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant on the market. It has been detected in various environmental samples, and a growing body of evidence has demonstrated its toxic effects on living organisms. In this study, we report the enrichment and phylogenetic identification of bacteria that debrominate TBBPA to bisphenol A in the presence of humin. Incubation experiments indicated that humin was required for this debromination activity. Of the five compounds examined for inclusion in the TBBPA-debrominating culture, formate was the optimal electron donor. A 16S rRNA gene library showed that the culture was dominated by three known dehalogenator genera: Dehalobacter, Geobacter, and Sulfurospirillum. Further investigation indicated that Dehalobacter was responsible for the debromination of TBBPA. PCR-denaturing gradient gel electrophoresis analysis showed that Dehalobacter grew in the culture by utilizing TBBPA. Moreover, the copy number of the Dehalobacter 16S rRNA genes increased by about two orders of magnitude in the cultures without the addition of TBBPA, whereas it increased by approximately four orders of magnitude when TBBPA was present. The incubation experiments showed that Dehalobacter was reliant on humin for its debromination activity, indicating a new type of metabolism in Dehalobacter that is linked to humin respiration.
Article
Tetrabromobisphenol A (TeBBPA) is a four-meta-brominated variant of bisphenol A (BPA) and is one of the most commonly used brominated flame retardants worldwide. We compared the estrogenic potency of TeBBPA, BPA and the brominated analogs mono- (MBBPA), di- (DBBPA), and tribromobisphenol A (TrBBPA) in the estrogen-dependent human breast cancer cell line MCF-7. All of the compounds competed with 17β-estradiol for binding to the estrogen receptor, although the affinity of the test chemicals to the estrogen receptor was much lower than that of 17β-estradiol. TrBBPA and TeBBPA showed a considerably lower access to the estrogen receptors within intact MCF-7 cells incubated in 100% serum compared to incubation in serum-free medium, indicating a strong binding to serum proteins. BPA, MBBPA, and DBBPA showed only a slightly reduced access to the receptors. All of the test compounds induced proliferation in MCF-7 cells, the potential decreasing with increasing number of bromo-substitutions. TeBBPA did not induce maximal cell growth, indicating cytotoxic effects at high concentrations. BPA and the brominated analogs, except TeBBPA, induced progesterone receptor and pS2 to the same extent as 17β-estradiol, although at much higher concentrations. Our studies demonstrate that compared to 17β-estradiol, BPA and the brominated analogs have much lower estrogenic potencies for all of the endpoints tested, TeBBPA being the least estrogenic compound.
Article
The aim of this study was to investigate the hormonal effects of tetrabromobisphenol A (TBBPA) in vitro on recombinant yeasts and in vivo on mosquitofish (Gambusia affinis). The in vitro bioassays for (anti-)androgenic activities showed that TBBPA had a weak androgenic activity in vitro with recombinant yeast systems carrying human androgen receptor (hAR). In the in vivo bioassays, the gene expression patterns of vitellogenin (Vtg), estrogen receptors (ERα and ERβ), and androgen receptors (ARα and ARβ) in adult males and juveniles after exposure to TBBPA for 60days were evaluated. Significant up-regulation of Vtg, ERα, and ERβ mRNAs was observed in the liver after exposure to 500 nM of TBBPA. In the testis, the lowest concentration of TBBPA (50 nM) markedly induced Vtg, ERβ, and ARβ mRNA expression, but the same concentration significantly inhibited ARα mRNA expression. In addition, in juveniles, 100 nM of TBBPA significantly up-regulated the expression of Vtg, ERβ, and ARα mRNAs. However, TBPPA did not cause histological alterations in the liver and testis of adult male mosquitofish. The results from this present study suggest that TBBPA could display low but multiple hormonal activities despite its low toxicity to mosquitofish.
Article
The widespread occurrence of the brominated flame retardant tetrabromobisphenol A (TBBPA) makes it a possible source of concern. Our experiments suggest that TBBPA can be effectively transformed by the naturally occurring laccase enzyme from Trametes versicolor. These reactions follow second-order kinetics, whereby apparent removal rate is a function of both substrate and enzyme concentrations. For reactions at different initial concentrations and with or without natural organic matter (NOM), reaction products are identified using liquid or gas chromatography with mass spectrometry. Detailed reaction pathways are proposed. It is postulated that two TBBPA radicals resulting from laccase-mediated reaction are coupled together via interaction of an oxygen atom on one radical and a propyl-substituted aromatic carbon atom on the other. A 2,6-dibromo-4-isopropylphenol carbocation is then eliminated from the radical dimer. All but one of the detected products arise from either substitution or proton elimination of the 2,6-dibromo-4-isopropylphenol carbocation. Three additional products are identified for reactions in the presence of NOM, which suggests that reaction occurs between NOM and TBBPA radical. Data from acute immobilization tests with Daphnia confirm that TBBPA toxicity is effectively eliminated by laccase-catalyzed TBBPA removal. These findings are useful for understanding laccase-mediated TBBPA reactions and could eventually lead to development of novel methods to control TBBPA contamination.
Article
Bisphenol A (BPA) is known as an endocrine disruptor and often is found in landfill leachates. Removal of BPA by green alga, Chlorella fusca, was characterized, because we previously found that various phenols were well removed by this strain, including BPA. Chlorella fusca was able to remove almost all BPA in the concentration range from 10 to 80 μM for 168 h under continuous illumination at 18 W/m2. At the low light intensity of 2 W/m2, 82% of 40 μM BPA was removed, and only 27% was removed in the dark. Moreover, C. fusca could remove 90% of 40 μM BPA under the 8:16-h light:dark condition, which was almost as high as that under the continuous-light condition. The amount of BPA contained in the cells was less than the amount of BPA removed from the medium. Monohydroxybisphenol A was detected as an intermediate of BPA degradation. Moreover, estrogenic activity that originated from BPA in the culture medium also completely disappeared. Based on these results, BPA was finally degraded to compounds having nonestrogenic activity. Therefore, C. fusca can be considered a useful organism to remove BPA from landfill leachates.
Article
The toxicity of bisphenol A (BPA) to Stephanodiscus hantzschii, a diatom isolated from tidal water of Futian Mangrove Nature Reserve, China, and the bioaccumulation and removal capability of the marine microalga to BPA were investigated in the present study. Toxicity experiments showed that the 96-h EC50 of BPA was 8.65±0.26 mg/L, and the cell number and chlorophyll a content of S. hantzschii decreased significantly with increases in BPA at concentrations higher than 3.00 mg/L. S. hantzschii had high removal capability at low BPA concentrations as BPA was bioaccumulated and biodegraded by cells. After 16-day treatment, 88%, 99%, 92%, 61%, 48%, 28% and 26% of BPA were removed by the diatom in the media supplemented with 0.01, 0.10, 1.00, 3.00, 5.00, 7.00 and 9.00 mg/L BPA, respectively. The present study demonstrated that S. hantzschii was a tolerant isolate that could be used to remove BPA from contaminated waters.
Article
Filings from a printed circuit board were extracted and analysed for unreacted tetrabromobisphenol A (TBBPA). About 0.7 μg free TBBPA per gram circuit board were found, corresponding to about 4 μg free TBBPA per gram of TBBPA used in the circuit board. These values are probably underestimates of the true levels due to incomplete extraction.Surficial sediments taken upstream and downstream from a plastics industry where TBBPA is used were analysed for both TBBPA and its dimethylated derivative, McTA. The TBBPA concentration was 34 ng/g dry weight upstream of the industry and 270 ng/g dry weight downstream. The corresponding concentrations of MeTA were 24 and 1500 ng/g dry weight respectively.TBBPA was also found in two sewage sludge samples analysed. One sample was collected from the sewage treatment plant that receives leach water from a landfill with wastes from the investigated plastics industry. The other sample was collected from a sewage treatment plant where no known users of TBBPA are connected. The levels of TBBPA in these samples were similar to those found in the samples upstream from the industry.During the analysis of a number of biological samples for lipophilic brominated substances, McTA has been screened, but so far no McTA has been detected.
Article
This study investigated the aerobic degradation of tetrabromobisphenol-A (TBBPA) and changes in the microbial community in river sediment from southern Taiwan. Aerobic degradation rate constants (k(1)) and half-lives (t(1/2)) for TBBPA (50 μg g(-1)) ranged from 0.053 to 0.077 d(-1) and 9.0 to 13.1 d, respectively. The degradation of TBBPA (50 μg g(-1)) was enhanced by adding yeast extract (5 mg L(-1)), sodium chloride (10 ppt), cellulose (0.96 mg L(-1)), humic acid (0.5 g L(-1)), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L(-1)), or surfactin (43 mg L(-1)), with rhamnolipid yielding a higher TBBPA degradation than the other additives. For different toxic chemicals in the sediment, the results showed the high-to-low order of degradation rates were bisphenol-A (BPA) (50 μg g(-1))>nonylphenol (NP) (50 μg g(-1))>4,4'-dibrominated diphenyl ether (BDE-15) (50 μg g(-1))>TBBPA (50 μg g(-1))>2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209) (50 μg g(-1)). The addition of various treatments changed the microbial community in river sediments. The results also showed that Bacillus pumilus and Rhodococcus ruber were the dominant bacteria in the process of TBBPA degradation in the river sediments.
Article
A novel bacterium, Ochrobactrum sp. T, capable of simultaneous debromination and aerobic mineralization of tetrabromobisphenol-A (TBBPA), was isolated from a sludge sample collected from an electronic-waste recycling site. The bacterium exhibited maximal debrominase activity at pH 6.5, 35 °C, and 200 rpm in Luria-Bertani culture medium. Initial TBBPA concentration and pH had more significant effects on degradation efficiency than those of temperature and inoculum size. Degradation and debromination efficiencies of 91.8% and 86.7%, respectively, were achieved within 72 h under optimized conditions of 35 °C, pH 7.0, inoculum volume of 25 mL, and TBBPA concentration of 3 mg L⁻¹. In addition, a 35.6% decrease in total organic carbon was observed after the degradation of 5 mg L⁻¹ TBBPA for 120 h. Eight metabolic intermediates were identified during the biodegradation of TBBPA. This study is the first report to propose a one-step process for TBBPA debromination and mineralization by a single bacterial strain.
Article
Birnessite (delta-MnO2) is a naturally occurring soil and sediment component that has been shown to oxidize organic compounds containing phenolic or aniline moieties. In this study, for the first time we explored the oxidation reaction of tetrabromobisphenol A (TBBPA), the most heavily used brominated flame retardant, with MnO2. TBBPA rapidly dissipated from the reaction solution and the process was accompanied by the dissolution of Mn2+. Dissipation of 50% of TBBPA occurred in less than 5 min in a system (pH 4.5) containing 625 microM MnO2 and 3.50 microM TBBPA at 21 degrees C, and the removal further increased to as high as 90% when the reaction was prolonged to 60 min. Analysis of initial reaction kinetics showed that the reaction orders with respect to TBBPA, MnO2, and H+ were 1.0, 0.8, and 0.25, respectively. Higher initial concentrations of TBBPA and MnO2 both enhanced the reaction. In addition, reaction rates increased as pH decreased. A retarded first-order model was found to closely describe the long-term reaction kinetics (R2 > or = 0.99), from which initial half-lives of TBBPA under different reaction conditions were estimated. A total of 7 reaction products were identified and a tentative reaction scheme was proposed. This study suggests that oxidative transformation of TBBPA by MnO2 may play an important role in the natural attenuation of TBBPA. The reaction may be further optimized for treatment of TBBPA-containing wastewater or remediation of TBBPA-polluted environmental matrices.
Article
Bisphenol-A (BPA), Triclosan (TCS) and Tetrabromobisphenol-A (TBBPA) are phenolic organic contaminants used in a variety of household applications. Through manufacture and usage, these contaminants can leach into the environment and can be detected in indoor dust. In this study, we determined the concentrations of BPA, TCS and TBBPA in indoor dust samples from 18 houses and 2 offices in Flanders, Belgium. The analysis was performed using solid-liquid extraction, clean-up and measurement by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Median concentrations of the 18 domestic dust samples were 1460, 220 and 10 ng g(-1) dust for BPA, TCS and TBBPA, respectively. Concentrations in offices were almost 5-10 times higher for BPA and TBBPA, while TCS concentrations were comparable at both locations. An assessment of the daily intake of these contaminants through dust was made and the contribution of dust to the total human exposure was calculated. For all three contaminants, dust seems to be a minor contributor (<10% of total exposure) to the total daily exposure. Food intake appears to be the major source of human exposure to BPA and TBBPA as dermal uptake through personal care products seems to be the major contributor for TCS.
Article
Polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA), and decabromodiphenylethane (DBDPE) were detected in fifteen surface sediments and two sediment cores collected from a river in one heavily industrialized region of South China. TBBPA and DBDPE were detected with concentrations ranging from 3.8 to 230 ng/g dw and from 23 to 430 ng/g dw, respectively. Sigma tri-hepta-BDEs and Sigma nona-deca-BDEs ranged from 0.7 to 7.6 ng/g dw and from 30 to 5700 ng/g dw, respectively. Sigma tri-hepta-BDEs showed an increasing trend whereas for Sigma nona-deca-BDE two sediment cores revealed a decreasing trend in more recent sediment layers which may attributed to the introduction of DBDPE. The rapid increasing trend for TBBPA and DBDPE in recent sediment layers well reflected the rising demand of these two compounds in study area.
Article
Hexabromocyclododecanes (alpha-, beta-, and gamma-HBCDs) and tetrabromobisphenol-A (TBBP-A) were determined in indoor air from homes (n=33; median concentrations sigma HBCDs = 180 pg m(-3); TBBP-A = 15 pg m(-3)), offices (n=25; 170; 11), public microenvironments (n=4; 900; 27) and outdoor air (n=5; 37; 1). HBCDs and TBBP-A were also determined in dust from homes (n=45; median concentrations sigma HBCDs = 1300 ng g(-1); TBBP-A = 62 ng g(-1)), offices (n=28; 760; 36), cars (n=20; 13,000; 2), and public microenvironments (n=4; 2700; 230). While sigma HBCDs in car dust significantly exceeded (p < 0.05) those in homes and offices, TBBP-A in car dust was significantly lower (p < 0.05) than that in homes and offices. No significant differences were observed between sigma HBCDs and TBBP-A in air or dust from homes and offices. Compared to dietary and inhalation exposures, dust ingestion constitutes an important pathway of exposure to HBCDs and TBBP-A for the UK population. Specifically, using average dust ingestion rates and concentrations in dust, dust ingestion constitutes for adults 34% (TBBP-A) and 24% (HBCDs) of overall exposure, and for toddlers 90% (TBBP-A) and 63% (HBCDs). Inhalation appears a minor exposure pathway to both HBCDs and TBBP-A. On average, dust is 33% alpha-, 11% beta-, and 56% gamma-HBCD, while air is 22% alpha-, 11% beta-, and 65% gamma-HBCD.
Article
The present article reviews the available literature on the analytical and environmental aspects of tetrabromobisphenol-A (TBBP-A), a currently intensively used brominated flame retardant (BFR). Analytical methods, including sample preparation, chromatographic separation, detection techniques, and quality control are discussed. An important recent development in the analysis of TBBP-A is the growing tendency for liquid chromatographic techniques. At the detection stage, mass-spectrometry is a well-established and reliable technology in the identification and quantification of TBBP-A. Although interlaboratory exercises for BFRs have grown in popularity in the last 10 years, only a few participating laboratories report concentrations for TBBP-A. Environmental levels of TBBP-A in abiotic and biotic matrices are low, probably due to the major use of TBBP-A as reactive FR. As a consequence, the expected human exposure is low. This is in agreement with the EU risk assessment that concluded that there is no risk for humans concerning TBBP-A exposure. Much less analytical and environmental information exists for the various groups of TBBP-A derivatives which are largely used as additive flame retardants.
Article
We demonstrated the O-methylation of tetrabromobisphenol-A (TBBPA) [4,4'-isopropylidenebis (2,6-dibromophenol)] to its mono- and dimethyl ether derivatives by microorganisms present in different sediments. A most probable number assay of a marsh sediment suggested that up to 10% of the total aerobic heterotrophs may be capable of O-methylation. Although TBBPA dimethyl ether is not produced in industry, it has been detected in terrestrial and aquatic sediments. Our study supports the hypothesis that TBBPA dimethyl ether is a product of microbial O-methylation. The O-methylation of TBBPA, as well as its analog, tetrachlorobisphenol-A (TCBPA), was also demonstrated in cultures of two chlorophenol-metabolizing bacteria, Mycobacterium fortuitum CG-2 and Mycobacterium chlorophenolicum PCP-1. These strains also mediated the O-methylation of 2,6-dibromophenol and 2,6-dichlorophenol, analogs of TBBPA and TCBPA, to their corresponding anisoles, but 2,6-fluorophenol was not transformed. Due to the addition of hydrophobic methyl groups, O-methylated derivatives are more lipophilic, increasing the probability of bioaccumulation in the food chain. Future research regarding the toxicological effects of the O-methylated derivatives of TBBPA is recommended and will further elucidate potential risks to environmental and human health.
Article
Considerable progress has been made in the last few years in understanding the mechanisms of microbial degradation of halogenated aromatic compounds. Much is already known about the degradation mechanisms under aerobic conditions, and metabolism under anaerobiosis has lately received increasing attention. The removal of the halogen substituent is a key step in degradation of halogenated aromatics. This may occur as an initial step via reductive, hydrolytic or oxygenolytic mechanisms, or after cleavage of the aromatic ring at a later stage of metabolism. In addition to degradation, several biotransformation reactions, such as methylation and polymerization, may take place and produce more toxic or recalcitrant metabolites. Studies with pure bacterial and fungal cultures have given detailed information on the biodegradation pathways of several halogenated aromatic compounds. Several of the key enzymes have been purified or studied in cell extracts, and there is an increasing understanding of the organization and regulation of the genes involved in haloaromatic degradation. This review will focus on the biodegradation and biotransformation pathways that have been established for halogenated phenols, phenoxyalkanoic acids, benzoic acids, benzenes, anilines and structurally related halogenated aromatic pesticides. There is a growing interest in developing microbiological methods for clean-up of soil and water contaminated with halogenated aromatic compounds.
Article
Air samples from a plant engaged in recycling electronics goods, a factory assembling printed circuit boards, a computer repair facility, offices equipped with computers, and outdoor air have been analyzed with respect to their content of brominated hydrocarbon and phosphate ester flame retardants. Polybrominated diphenyl ethers, polybrominated biphenyls, 1,2-bis(2,4,6-tribromophenoxy)-ethane, tetrabromobisphenol A, and organophosphate esters were all detected in the indoor air samples, with the highest concentrations being detected in air from the recycling plant. In air from the dismantling hall at the recycling plant the average concentrations of decabromodiphenyl ether, tetrabromobisphenol A, and triphenyl phosphate were 38, 55, and 58 pmol/m3, respectively. Significantly higher levels of all of these additives were present in air in the vicinity of the shredder at the dismantling plant. This is the first time that 1,2-bis(2,4,6-tribromophenoxy)-ethane and several arylated phosphate esters are reported to be contaminants of air in occupational settings. At all of the other sites investigated, low levels of flame retardants were detected in the indoor air. Flame retardants associated with airborne particles, present at elevated levels, pose a potential health hazard to the exposed workers.
Article
Brominated flame retardants (BFRs) are used in a variety of consumer products and several of those are produced in large quantities. These compounds have been detected in environmental samples, which can be attributed to the anthropogenic uses of these compounds. Brominated flame retardants are produced via direct bromination of organic molecules or via addition of bromine to alkenes; hence, an overview of the production and usage of bromine over the past three decades is covered. Production, application, and environmental occurrence of high production brominated flame retardants including Tetrabromobisphenol A, polybrominated biphenyls, Penta-, Octa-, Deca-brominated diphenyl ether (oxide) formulation and hexabromocyclododecane are discussed.
Article
A method was developed for studies of the phototransformation at UV irradiation of aqueous solutions of tetrabromobisphenol A (TBBPA), tribromobisphenol A (TriBBPA), tetrachlorobisphenol A (TCBPA), 2,4-dichlorophenol at various pHs as well as 2-chlorophenol, 2-bromophenol, 3,4-dichlorophenol and bisphenol A at pH 11. The absorbance spectra of the compounds and the emission spectra of the light-source were determined and used to calculate disappearance quantum yields of the photochemical reactions that were taking place. No major differences between the disappearance quantum yields of TBBPA and TCBPA were observed at pH 10, while the disappearance quantum yield of TriBBPA was approximately two times higher. The rate of decomposition of TBBPA was six times higher at pH 8 than at pH 6. Identification of the degradation products of TBBPA and TriBBPA, by GC-MS analysis and by comparison to synthesised reference compounds, indicated that TBBPA and TriBBPA decompose via different mechanisms. Three isopropylphenol derivatives; 4-isopropyl-2,6-dibromophenol, 4-isopropylene-2,6-dibromophenol and 4-(2-hydroxyisopropyl)-2,6-dibromophenol, were identified as major degradation products of TBBPA while the major degradation product of TriBBPA was tentatively identified as 2-(2,4-cyclopentadienyl)-2-(3,5-dibromo-4-hydroxyphenyl)propane.
Article
An aquatic community was recovered from a waste discharge container fed with several aromatic pollutants. After 3 months of selective enrichment with p-chlorophenol and p-nitrophenol, two microalgae species, Chlorella vulgaris and Coenochloris pyrenoidosa, were recovered from the microbial consortium. As an axenic culture, this microalgae consortium was able to remove p-chlorophenol under different photo-regimes. Cultures grown under a 24h light regime were capable of biodegrading 50mg l(-1) of p-chlorophenol within 5 days. Addition of zeolite, an adsorbing material, did not improve the p-chlorophenol removal. However, when p-chlorophenol at 150mgl(-1) was fed to the culture supplemented with zeolite, the growth rate of the consortium improved, but the lag phase was longer (16 against 14 days in the absence of zeolite).
Article
The role of algae in the persistence, transformation, and bioremediation of two endocrine disrupting chemicals, alpha-endosulfan (a cyclodiene insecticide) and its oxidation product endosulfan sulfate, in soil (incubated under light or in darkness) and a liquid medium was examined. Incubation of soil under light dramatically decreased the persistence of alpha-endosulfan and enhanced its transformation to endosulfan sulfate, over that of dark-incubated soil samples, under both nonflooded and flooded conditions. This enhanced degradation of soil-applied alpha-endosulfan was associated with profuse growth of indigenous phototrophic organisms such as algae in soil incubated under light. Inoculation of soil with green algae, Chlorococcum sp. or Scenedesmus sp., further enhanced the degradation of alpha-endosulfan. The role of algae in alpha-endosulfan degradation was convincingly demonstrated when these algae degraded alpha-endosulfan to endosulfan sulfate, the major metabolite, and endosulfan ether, a minor metabolite, in a defined liquid medium. When a high density of the algal inoculum was used, both metabolites appeared to undergo further degradation as evident from their accumulation only in small amounts and the appearance of an endosulfan-derived aldehyde. Interestingly, beta-endosulfan was detected during degradation of alpha-endosulfan by high density algal cultures. These algae were also capable of degrading endosulfan sulfate but to a lesser extent than alpha-endosulfan. Evidence suggested that both alpha-endosulfan and endosulfan sulfate were immediately sorbed by the algae from the medium, which then effected their degradation. Biosorption, coupled with their biotransformation ability, especially at a high inoculum density, makes algae effective candidates for remediation of alpha-endosulfan-polluted environments.
Article
Leachate samples were taken from seven different landfills and concentrations of brominated flame retardants (BFRs), i.e. polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), were quantified. Leaching characteristics of BFRs, especially factors affecting leachability, were clarified to obtain basic information regarding the release of BFRs into the environment. The results obtained for observed levels of the sum of PBDE-47, -99 and -100 were n.d.--4000 pg/l for the raw leachate and n.d. for the treated one, respectively, and those of TBBPA were n.d.--620,000 pg/l for the raw leachate and n.d.--11,000 pg/l for the treated one, respectively. Three sites that not only had crushed material from bulk wastes such as waste electric and electronic equipment, but also were under operation or within a year since closure, indicated a higher concentration of BFRs than the other sites. In particular extremely high concentration of PBDEs was observed at a site with a large amount of organics. Considering the leaching characteristics of BFRs, there exists the possibility that leachability of PBDEs is influenced by the presence of dissolved humic matter (DHM) in the leachate. The high removal efficiency for BFRs in the leachate treatment process was also confirmed.
Article
Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane diastereoisomers (alpha-, beta/-, and gamma-HBCD) were investigated in effluents from sewage treatment works, landfill leachates, sediments, and food web organisms of the North Sea basin. Residues were quantified by liquid chromatography-mass spectrometry. Both flame retardants were enriched in sewage sludges, where a maximum total (sigma) HBCD concentration of 9.1 mg/kg (dry weight; d.w.) was found; TBBPA was at levels of 102 microg/kg. Landfill leachates from The Netherlands showed up to 36 mg (sigmaHBCD)/ kg (d.w.). gamma-HBCD dominated isomeric profiles in sediments, and concentrations were elevated near to a site of HBCD manufacture. alpha-HBCD was the primary congener detected in marine mammals; however, very few samples exhibited TBBPA. sigmaHBCD ranged from 2.1 to 6.8 mg/kg (lipid weight; l.w.) in liver and blubber of harbor porpoises (Phocoena phocoena) and seals (Phoca vitulina). TBBPA levels in cormorant (Phalacrocorax carbo) livers were up to 1 order of magnitude lower compared to sigmaHBCD. HBCD in eels (Anguilla anguilla) from the Scheldt basin (Belgium) reflected the spatial distribution of concentrations in local sediments. This study shows evidence of HBCD bioaccumulation at the trophic level and biomagnification in the ascending aquatic food chain, and these findings justify risk assessment studies at the ecosystem level.
Article
The endocrine-disrupting activities of bisphenol A (BPA) and 19 related compounds were comparatively examined by means of different in vitro and in vivo reporter assays. BPA and some related compounds exhibited estrogenic activity in human breast cancer cell line MCF-7, but there were remarkable differences in activity. Tetrachlorobisphenol A (TCBPA) showed the highest activity, followed by bisphenol B, BPA, and tetramethylbisphenol A (TMBPA); 2,2-bis(4-hydroxyphenyl)-1-propanol, 1,1-bis(4-hydroxyphenyl)propionic acid and 2,2-diphenylpropane showed little or no activity. Anti-estrogenic activity against 17beta-estradiol was observed with TMBPA and tetrabromobisphenol A (TBBPA). TCBPA, TBBPA, and BPA gave positive responses in the in vivo uterotrophic assay using ovariectomized mice. In contrast, BPA and some related compounds showed significant inhibitory effects on the androgenic activity of 5alpha-dihydrotestosterone in mouse fibroblast cell line NIH3T3. TMBPA showed the highest antagonistic activity, followed by bisphenol AF, bisphenol AD, bisphenol B, and BPA. However, TBBPA, TCBPA, and 2,2-diphenylpropane were inactive. TBBPA, TCBPA, TMBPA, and 3,3'-dimethylbisphenol A exhibited significant thyroid hormonal activity towards rat pituitary cell line GH3, which releases growth hormone in a thyroid hormone-dependent manner. However, BPA and other derivatives did not show such activity. The results suggest that the 4-hydroxyl group of the A-phenyl ring and the B-phenyl ring of BPA derivatives are required for these hormonal activities, and substituents at the 3,5-positions of the phenyl rings and the bridging alkyl moiety markedly influence the activities.