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Chen G, Jiang X, Gu C, Sun C, Li M. Bioaccessibility of BDE 47 in a simulated gastrointestinal system and its metabolic transformation mechanisms in Caco-2 cells. CHEMOSPHERE 2019; 214:408-417. [PMID: 30268896 DOI: 10.1016/j.chemosphere.2018.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 08/29/2018] [Accepted: 09/02/2018] [Indexed: 06/08/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) have been regarded as ubiquitous environmental pollutants. However, the absorption and transformation of these compounds after ingestion are not well understood yet. In this study, the bioaccessibility and metabolic pathway of 2,2',4,4'- tetrabromodiphenyl ether (BDE47) was investigated in an in vitro digestion/Caco-2 cell. Gastric and intestinal bioaccessibilities of BDE47 in 5 kinds of spiked soil samples were ranging from 11.39 ± 0.83% to 36.02 ± 4.34%, and 48.24 ± 3.24% to 81.52 ± 6.43%, respectively. Upon exposure to differentiated Caco-2 cells for 6 h, it was found that only a small amount of BDE47 in the gastrointestinal (GI) solution could pass through Caco-2 cells, and might enter the body. Moreover, BDE47 was found to be metabolized or transformed into BDE28, BDE75, BDE37, BDE32, BDE15 and BDE8 in Caco-2 cells. The metabolic pathway could be explained by using the Becke three-parameter hybrid functional (B3Lucifer yellow CHP) in the Density Functional Theory (DFT), denoted as the values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the atoms of BDE47 and its metabolic products. The obtained results suggest that oral intake of PBDEs is associated with low bioaccessibility, but also emphasize the risks associated with oral ingestion, namely toxicity resulting from the debromination of highly brominated diphenyl ethers. Although highly brominated diphenyl ethers are known to be the least toxic PBDEs, the debrominated products in human intestinal epithelia may elicit greater than expected toxicity.
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Affiliation(s)
- Guangchun Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China; Department of Environmental Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China
| | - Xiaofeng Jiang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Chenggang Gu
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Cheng Sun
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
| | - Mei Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
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Khaled A, Rivaton A, Richard C, Jaber F, Sleiman M. Phototransformation of Plastic Containing Brominated Flame Retardants: Enhanced Fragmentation and Release of Photoproducts to Water and Air. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:11123-11131. [PMID: 30169020 DOI: 10.1021/acs.est.8b03172] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Increasing attention is being paid to the environmental fate and impact of plastics and their additives under sunlight exposure. We evaluated the photodegradation of polystyrene (PS) films (∼100 μm) containing brominated flame retardants (BFRs): decabromodiphenylether (BDE-209), tetrabromobisphenol A (TBBPA), and tetrabromobisphenol A-bis (2.3-dibromopropylether) (TBBPA-DBPE). Irradiations were performed in a solar simulator and outdoors. Infrared (IR) analyses indicated an acceleration of the photooxidation rate of fire-retarded PS films compared to pure PS with an enhancement factor of 7 for TBBPA-DBPE and TBBPA, and 10 for BDE-209. The accelerating effect was found to be correlated with the quantum yield for BFR photodegradation and its absorbance in the PS films. The presence of BFRs also modified the PS photooxidation mechanism and resulted in the formation of 14 brominated photoproducts via bromination and oxidation of PS. Furthermore, a drastic increase in chain scissions and loss of molecular weight was revealed by size exclusion chromatography. This enhanced degradation of PS led to significant leaching (15%) of oxidation products from PS films after immersion in water, and to the gas-phase emission of several volatile brominated products. Our findings suggest that fire-retarded plastics may be a source of potentially hazardous contaminants when exposed to sunlight.
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Affiliation(s)
- Amina Khaled
- Université Clermont Auvergne, CNRS, SIGMA Clermont , Institut de Chimie de Clermont-Ferrand , F-63000 Clermont-Ferrand , France
| | - Agnès Rivaton
- Université Clermont Auvergne, CNRS, SIGMA Clermont , Institut de Chimie de Clermont-Ferrand , F-63000 Clermont-Ferrand , France
| | - Claire Richard
- Université Clermont Auvergne, CNRS, SIGMA Clermont , Institut de Chimie de Clermont-Ferrand , F-63000 Clermont-Ferrand , France
| | - Farouk Jaber
- Laboratory of Analysis of Organic Compounds (509), Faculty of Sciences I , Lebanese University , Hadath, Beirut , Lebanon
| | - Mohamad Sleiman
- Université Clermont Auvergne, CNRS, SIGMA Clermont , Institut de Chimie de Clermont-Ferrand , F-63000 Clermont-Ferrand , France
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Luo J, Hu J, Wei X, Fu L, Li L. Dehalogenation of persistent halogenated organic compounds: A review of computational studies and quantitative structure-property relationships. CHEMOSPHERE 2015; 131:17-33. [PMID: 25765260 DOI: 10.1016/j.chemosphere.2015.02.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 12/20/2014] [Accepted: 02/03/2015] [Indexed: 06/04/2023]
Abstract
Dehalogenation is one of the highly important degradation reactions for halogenated organic compounds (HOCs) in the environment, which is also being developed as a potential type of the remediation technologies. In combination with the experimental results, intensive efforts have recently been devoted to the development of efficient theoretical methodologies (e.g. multi-scale simulation) to investigate the mechanisms for dehalogenation of HOCs. This review summarizes the structural characteristics of neutral molecules, anionic species and excited states of HOCs as well as their adsorption behavior on the surface of graphene and the Fe cluster. It discusses the key physiochemical properties (e.g. frontier orbital energies and thermodynamic properties) calculated at various levels of theory (e.g. semiempirical, ab initio, density functional theory (DFT) and the periodic DFT) as well as their connections to the reactivity and reaction pathway for the dehalogenation. This paper also reviews the advances in the linear and nonlinear quantitative structure-property relationship models for the dehalogenation kinetics of HOCs and in the mathematical modeling of the dehalogenation processes. Furthermore, prospects of further expansion and exploration of the current research fields are described in this article.
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Affiliation(s)
- Jin Luo
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, PR China
| | - Jiwei Hu
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, PR China.
| | - Xionghui Wei
- Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China
| | - Liya Fu
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, PR China
| | - Lingyun Li
- Guizhou Provincial Key Laboratory for Information Systems of Mountainous Areas and Protection of Ecological Environment, Guizhou Normal University, Guiyang 550001, PR China
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Zou Y, Christensen ER, Zheng W, Wei H, Li A. Estimating stepwise debromination pathways of polybrominated diphenyl ethers with an analogue Markov Chain Monte Carlo algorithm. CHEMOSPHERE 2014; 114:187-194. [PMID: 25113201 DOI: 10.1016/j.chemosphere.2014.04.072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 06/03/2023]
Abstract
A stochastic process was developed to simulate the stepwise debromination pathways for polybrominated diphenyl ethers (PBDEs). The stochastic process uses an analogue Markov Chain Monte Carlo (AMCMC) algorithm to generate PBDE debromination profiles. The acceptance or rejection of the randomly drawn stepwise debromination reactions was determined by a maximum likelihood function. The experimental observations at certain time points were used as target profiles; therefore, the stochastic processes are capable of presenting the effects of reaction conditions on the selection of debromination pathways. The application of the model is illustrated by adopting the experimental results of decabromodiphenyl ether (BDE209) in hexane exposed to sunlight. Inferences that were not obvious from experimental data were suggested by model simulations. For example, BDE206 has much higher accumulation at the first 30 min of sunlight exposure. By contrast, model simulation suggests that, BDE206 and BDE207 had comparable yields from BDE209. The reason for the higher BDE206 level is that BDE207 has the highest depletion in producing octa products. Compared to a previous version of the stochastic model based on stochastic reaction sequences (SRS), the AMCMC approach was determined to be more efficient and robust. Due to the feature of only requiring experimental observations as input, the AMCMC model is expected to be applicable to a wide range of PBDE debromination processes, e.g. microbial, photolytic, or joint effects in natural environments.
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Affiliation(s)
- Yonghong Zou
- Department of Civil Engineering and Mechanics, University of Wisconsin - Milwaukee, Milwaukee, WI 53211, United States; Illinois Sustainable Technology Center, University of Illinois Urbana - Champaign, Champaign, IL 61820, United States.
| | - Erik R Christensen
- Department of Civil Engineering and Mechanics, University of Wisconsin - Milwaukee, Milwaukee, WI 53211, United States
| | - Wei Zheng
- Illinois Sustainable Technology Center, University of Illinois Urbana - Champaign, Champaign, IL 61820, United States
| | - Hua Wei
- School of Public Health, University of Illinois - Chicago, Chicago, IL 60612, United States
| | - An Li
- School of Public Health, University of Illinois - Chicago, Chicago, IL 60612, United States
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Nadjia L, Abdelkader E, Ulrich M, Bekka A. Spectroscopic behavior of saytex 8010 under UV-visible light and comparative thermal study with some flame bromine retardant. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2013.11.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Larsson M, Kumar Mishra B, Tysklind M, Linusson A, Andersson PL. On the use of electronic descriptors for QSAR modelling of PCDDs, PCDFs and dioxin-like PCBs. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2013; 24:461-479. [PMID: 23724952 DOI: 10.1080/1062936x.2013.791719] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The electronic properties of 29 polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls that have been included in the toxic equivalency factor system have been investigated and used to derive quantum mechanical (QM) chemical descriptors for QSAR modelling. Their utility in this context was investigated alongside descriptors based on ultraviolet absorption data and traditional 2D descriptors including log K(ow), polarizability, molecular surface properties, van der Waals volume and selected connectivity indices. The QM descriptors were calculated using the semi-empirical AM1 method and the density functional theory method B3-LYP/6-31G**. Atom-specific and molecular quantum chemical descriptors were calculated to compare the electronic properties of dioxin-like compounds regardless of their chemical class, with particular emphasis on the lateral positions. Multivariate analysis revealed differences between the chemical classes in terms of their electronic properties and also highlighted differences between congeners. The results obtained demonstrated the importance of considering molecular orbital energies, but also indicated that the ratios of the coefficients of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) at the lateral carbons were important. In addition, the digitalized UV spectra contained chemical information that provided crucial insights into dioxin-like activity.
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Affiliation(s)
- M Larsson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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A Quantitative Structure-Property Relationship Study on Photodegradation of Polybrominated Diphenyl Ethers. ACTA ACUST UNITED AC 2012. [DOI: 10.4028/www.scientific.net/amr.546-547.48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantitative structure-property relationship (QSPR) models were developed in the present work for photodegradation rate constants (kp) of fifteen individual polybrominated diphenyl ethers (PBDEs) in methanol/water (8:2) by UV light in the sunlight region. The molecular descriptors used in the QSPR models were calculated by the two semi-empirical quantum mechanical methods, RM1 and PM6, respectively. Both multiple linear regression (MLR) and artificialneural network (ANN) were applied in this study. The statistic qualities of the MLR models based on the molecular parameters obtained by RM1 and PM6 calculations were both good with the R values of 0.987 and 0.990, respectively. The QSPR model built by the ANN method with the molecular parameters calculated with PM6 is slightly better than that with RM1.
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Rayne S, Forest K. pK(a) values of the monohydroxylated polychlorinated biphenyls (OH-PCBs), polybrominated biphenyls (OH-PBBs), polychlorinated diphenyl ethers (OH-PCDEs), and polybrominated diphenyl ethers (OH-PBDEs). JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2010; 45:1322-46. [PMID: 20658412 DOI: 10.1080/10934529.2010.500885] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The SPARC software program aqueous pK(a) prediction module was validated against corresponding experimental acidity constants for chlorinated and brominated phenols and the limited experimental aqueous pK(a) data sets for monohydroxylated polychlorinated biphenyls (OH-PCBs), polychlorinated diphenyl ethers (OH-PCDEs), and polybrominated diphenyl ethers (OH-PBDEs). pK(a) values were then estimated for all 837 monohydroxylated mono- through nona-halogenated congeners in each of the OH-PCB, OH-PCDE, and OH-PBDE classes, as well as for the monohydroxylated polybrominated biphenyls (OH-PBBs), giving a total of 3348 compounds. Large intrahomolog pK(a) variation by up to six units is expected within each contaminant class, with pK(a) values ranging from about 4 to 11 dependent on the degree and pattern of halogenation. Increasing halogenation generally decreased the average pK(a) within each homolog group. Significant intrahomolog differences in pK(a) values exist between OH-PCB, OH-PBB, OH-PCDE, and OH-PBDE congeners, including large acidity constant variation between isomers with equivalent halogenation patterns but varying location of the hydroxy moiety. Congener specific pH dependent investigations into the partitioning and degradation behaviors of these compounds are necessary, including greater consideration of analyte ionization effects during their extraction and analysis.
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Affiliation(s)
- Sierra Rayne
- Ecologica Research, Penticton, British Columbia, Canada.
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