Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time （RRT） of polybrominated diphenyl ethers （PBDEs） were predic...Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time （RRT） of polybrominated diphenyl ethers （PBDEs） were predicted. A four-variable regression model （M30） with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom -C= and -C=, -C= and 〉C=, 〉C= and 〉C=, -C= and -Br.展开更多
We measured 39 polybrominated diphenyl ethers （PBDEs） in the muscle tissue of three species of fish （Sciaenops ocellatus,Sparus macrocephalus,and Lateolabrax japonicus） and four species of shellfish （Tegillarca g...We measured 39 polybrominated diphenyl ethers （PBDEs） in the muscle tissue of three species of fish （Sciaenops ocellatus,Sparus macrocephalus,and Lateolabrax japonicus） and four species of shellfish （Tegillarca granosa,Cyclina sinensis,Sinonovacula constricta,and Ostrea cucullata） that were collected downstream of electronic-waste recycling plants in Taizhou,China.A total of 24 PBDE congeners （PBDE 24） in the samples were detected.The PBDE 24 （total PBDE） ranged from 545.4 to 1688.7 ng/kg ww （wet weight）.The mean PBDE 24 concentration was 1382.6 ng/kg ww in fish and 858.1 ng/kg ww in shellfish.The lower brominated congeners were detected at relatively high concentrations in all species.The penta-products,produced from e-waste,were found at relatively low levels.A principal component analysis suggested a significant correlation among di-,tri-,tetra-,and hepta-BDEs for the three species of fish.Similarly,we found a significant correlation between mono-and tri-BDEs in the shellfish.Our results suggested that the processes of PBDE metabolism and elimination were similar in both fish and shellfish.In addition,the primary source of PBDEs appeared to be from the debromination of high brominated PBDEs.展开更多
Objective：To investigate the metabolites of polybrominated diphenyl ether 99（BDE-99）and its related cytochrome P450s in an in vitro system.Methods：Rat primary hepatocytes were isolated and treated with BDE-99 for ...Objective：To investigate the metabolites of polybrominated diphenyl ether 99（BDE-99）and its related cytochrome P450s in an in vitro system.Methods：Rat primary hepatocytes were isolated and treated with BDE-99 for 24-72 h.Metabolites were then extracted from the hepatocytes and media,and detected by GC/MS.Several mRNAs of metabolic enzymes were also extracted from the same cells and the gene expression levels were determined using quantitative real-time PCR.In addition,selected recombinant cytochrome P450s（CYPs） were expressed in a bacurovirus/sf9 system,and these were further used to explore the metabolism of BDE-99 in vitro.The parent depletion approach was used for screening the ability of CYPs to eliminate BDE-99.Results： A reductively debrominated metabolite,BDE-47,and three oxidative metabolites,2,4,5-tribromophenol,5-OH-BDE-47,and 5＇-OH-BDE-99,were identified from the BDE-99-treated rat hepatocytes,whereas no MeO metabolite was detected in the system.RT-PCR analysis showed that CYP 3A23/3A1,1A2,and 2B1/2 were induced by BDE-99.Furthermore,using the heterological expressed CYP proteins in in vitro BDE-99 metabolism experiments we found that CYP1A2 and CYP3A4 showed the highest metabolic efficiency for BDE-99,with the metabolic clearance rates of CYP1A2 and CYP3A4 being 30.3%and 27.7%,respectively.CYP1A1 and CYP2A6 displayed relatively low clearance rates,while CYP2E1 seemed not to be associated with the BDE-99 metabolism.Conclusions：In our in vitro rat primary hepatocyte metabolism system,four metabolites of BDE-99 were identified,and CYP3A4 and CYP1A2 were demonstrated to be involved in the BDE-99 metabolism.展开更多
Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether( PBDE) congeners( BDE17,28,47,66,99,100,153,154,138,183,and BDE-209) were detected to state the po...Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether( PBDE) congeners( BDE17,28,47,66,99,100,153,154,138,183,and BDE-209) were detected to state the pollution situation. The results showed that the total concentration of total PBDEs ranges from 0. 424 to 23. 0 ng / g dry weight,with the mean of 3. 02 ng / g,and the total PBDEs concentration is at relative low level compared with those worldwide. The congener profile showed that BDE-209 is the dominant congener that accounts for more than 80. 1% of total PBDEs in sediments,followed by BDE-47 and BDE-99. These profiles are consistent with a high consumption of Deca-BDEs for the brominated flame retardant market in China. The results of spatial and seasonal observations indicated that local sources,temperature variation, and hydrologic conditions are significant factors on PBDEs concentrations. Hazard quotients suggested that PBDEs pose no potential risk to benthic organisms in detected area at present.展开更多
PBDEs are widely used brominated flame retardant, which are increasingly reported in the environment. Concentrations of thirteen PBDEs in a large number of channel catfish and fish feeds collected from Hubei province ...PBDEs are widely used brominated flame retardant, which are increasingly reported in the environment. Concentrations of thirteen PBDEs in a large number of channel catfish and fish feeds collected from Hubei province of China were investigated in this study. A fast isotopic dilution GC-MS method was firstly developed to simultaneously determine thirteen PBDEs in channel catfish and fish feeds in this study, and especially for the first time PBDEs in fish feeds. Pressurized liquid extraction and multi-layer silica gel column chromatography cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures, and GC and MS conditions were optimized. The limits of quantitation values of 0.25 - 5 μg·kg-1 wet weight in channel catfish were calculated for PBDEs;so did 1 - 20 μg·kg-1 wet weight in fish feeds. In addition, good repeatability and accuracy of the whole method were achieved. The established methods were therefore suitable for the simultaneous determinations of thirteen PBDEs in these samples at trace contamination levels. Using the established methods, PBDEs emerged in 10 of 180 channel catfish and 13 of 115 fish feeds, and the dominant PBDEs homologues were PBDE-28, PBDE-47, PBDE-100, PBDE-99, PBDE-154, PBDE-153 and PBDE-183. The detection rates of seven PBDEs congeners were in turn respectively 1.74%, 7.83%, 4.35%, 5.22%, 3.48%, 2.61% and 2.61% in fish feeds, and detection rates of seven PBDEs congeners were in turn respectively 1.11%, 3.89%, 2.22%, 1.67%, 1.11%, 1.11% and 1.11% in channel catfish. There was significant correlation in PBDEs between matching channel catfish and fish feeds (R2 = 0.742, P < 0.001, n = 30), suggesting that fish feeds contaminated with PBDEs possibly resulted in PBDEs residual in channel catfish through biological transfer.展开更多
This review focuses on the occurrence and interactions of engineered nanoparticles(ENPs)and brominated flame retardants(BFRs)such as polybrominated diphenyl ethers(PBDEs)in water systems and the generation of highly c...This review focuses on the occurrence and interactions of engineered nanoparticles(ENPs)and brominated flame retardants(BFRs)such as polybrominated diphenyl ethers(PBDEs)in water systems and the generation of highly complex compounds in the environment.The release of ENPs and BFRs(e.g.PBDEs)to aquatic environments during their usage and disposal are summarised together with their key interaction mechanisms.The major interaction mechanisms including electrostatic,van derWaals,hydrophobic,molecular bridging and steric,hydrogen andπ-bonding,cation bridging and ligand exchange were identified.The presence of ENPs could influence the fate and behaviour of PBDEs through the interactions as well as induced reactions under certain conditions which increases the formation of complex compounds.The interaction leads to alteration of behaviour for PBDEs and their toxic effects to ecological receptors.The intermingled compound(ENPs-BFRs)would show different behaviour from the parental ENPs or BFRs,which are currently lack of investigation.This review provided insights on the interactions of ENPs and BFRs in artificial,environmental water systems and wastewater treatment plants(WWTPs),which are important for a comprehensive risk assessment.展开更多
Polybrominated diphenyl ethers(PBDEs)are widely used as brominated flame retardants,which had attracted amounts of attention due to their harmful characteristics of high toxicity,environmental persistence and potentia...Polybrominated diphenyl ethers(PBDEs)are widely used as brominated flame retardants,which had attracted amounts of attention due to their harmful characteristics of high toxicity,environmental persistence and potential bioaccumulation.Many chemical reductive debromination technologies have been developed for the debromination of PBDEs,including photolysis,photocatalysis,electrocatalysis,zero-valent metal reduction,chemically catalytic reduction and mechanochemical method.This review aims to provide information about the degradation thermodynamics and kinetics of PBDEs and summarize the degradation mechanisms in various systems.According to the comparative analysis,the rapid debromination to generate bromine-free products in an electron-transfer process,of which photocatalysis is a representative one,is found to be relatively difficult,because the degradation rate of PBDEs depended on the Br-rich phenyl ring with the lowest unoccupied molecular orbital(LUMO)localization.On the contrary,the complete debromination occurs easily in other systems with active hydrogen atoms as the main reactive species,such as chemically catalytic reduction systems.The review provides the knowledge on the chemical reductive technique of PBDEs,which would greatly help not only clarify the degradation mechanism but also design the more efficient system for the rapid and deep debromination of PBDEs in the future.展开更多
The spatial,temporal,and vertical distributions of polybrominated diphenyl ethers(PBDEs) in water columns from the Zhujiang River Estuary were examined,and the partition behavior of PBDEs between particle and dissolve...The spatial,temporal,and vertical distributions of polybrominated diphenyl ethers(PBDEs) in water columns from the Zhujiang River Estuary were examined,and the partition behavior of PBDEs between particle and dissolved phases was investigated in the present study.The results show that the distributions of PBDEs concentrations in the water varied with the sampling seasons.The PBDEs concentrations in water samples were lower in May 2005,when the brackish water was dominant in the estuary,than in October 2005,when fresh water from river runoff dominated the estuary.The spatial distribution of PBDEs in October 2005 indicated that the river runoff was the major mode to input PBDEs to the estuary,and the concentration of PBDEs in water might be dissolved organic carbon(DOC) dependence.The spatial and vertical distributions of PBDEs in May 2005 were relatively homogeneous,and SPM was the major factor on controlling the levels of PBDEs in this sampling time.Both DOC and POC could play certain roles in determining the distribution and partition of PBDEs between particle and dissolved phases,but their effects varied with the water properties.展开更多
Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the li...Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the limited experimental data, it is important and necessary to develop structure-based models for prediction of the toxicity of the compounds. In this study, a new molecular structure representation, molecular hologram, was employed to investigate the quantitative relationship between toxicity and molecular structures for 18 PBDEs. The model with the significant correlation and robustness (r <sup>2</sup> = 0.991, q <sup>2</sup> <sub>LOO</sub> = 0.917) was developed. To verify the robustness and prediction capacity of the derived model, 14 PBDEs were randomly selected from the database as the training set, while the rest were used as the test set. The results generated under the same modeling conditions as the optimal model are as follows: r <sup>2</sup> = 0.988, q <sup>2</sup> <sub>LOO</sub> = 0.598, r <sup>2</sup> <sub>pred</sub> = 0.955, and RMSE (root-mean-square of errors) = 0.155, suggesting the excellent ability of the derived model to predict the toxicity of PBDEs. Furthermore, the structural features and molecular mechanism related to the toxicity of PBDEs were explored using HQSAR color coding.展开更多
Polybrominated diphenyl ethers(PBDEs)have been used as flame retardants in various building materials,plastic and other polymers,airplanes,electronics,etc.All or some of their congeners have been already banned in man...Polybrominated diphenyl ethers(PBDEs)have been used as flame retardants in various building materials,plastic and other polymers,airplanes,electronics,etc.All or some of their congeners have been already banned in many countries,due to their persistency and adverse health effects.In this study,we are focusing on e-wastes as a source of emission of PBDEs in ambient air during reclamation processes.The ambient air particulate matter(PM)samples were collected at and near an e-waste reclamation site in Bangkok,Thailand.Results showed the presence of various homologues,viz:tri-,tetra-,penta-,hexa-,and hepta-PBDEs in both PM2.5 and total suspended particle(TSP)samples.The comparison of samples as a function of distance from the reclamation site indicated elevated levels of PBDEs in close proximity to the e-waste site.Interestingly,a shift in the congener pattern was observed with lower brominated PBDEs being more prevalent in nearby off-site samples as compared to the PM collected at the e-waste site.The total penta-PBDEs concentration is almost double in the e-waste site PM2.5 compared to the control site samples.For TSP,tetra,penta,and hepta-PBDEs congeners are at higher concentrations at the e-waste sites and its vicinity compared to reference sites.Overall,a clear trend can be observed indicating a debromination of PBDEs to more toxic tri and tetra congeners during the reclamation process and PBDEs are being translocated from treated materials to ambient air PM.BDE 30 is uniquely detected in our studies as a dominant final debromination product,that can be used as a marker of thermal e-waste activity.This work indicates potential hazards related to the reclamation of e-wastes and remediation of sites containing PBDEs.In particular,thermal treatment methods can lead to congener transformation and increased emissions of more toxic lower brominated congeners.展开更多
基金the National Basic Research Program of China(2003CB415002)the National Natural Science Foundation of China(No.20377022) the Guangxi Natural Science Fund(No.0236063)for their financial supports.
文摘Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time （RRT） of polybrominated diphenyl ethers （PBDEs） were predicted. A four-variable regression model （M30） with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom -C= and -C=, -C= and 〉C=, 〉C= and 〉C=, -C= and -Br.
基金supported by the Wenling Science and Technology Bureau of Zhejiang Province (No. 2007-35)
文摘We measured 39 polybrominated diphenyl ethers （PBDEs） in the muscle tissue of three species of fish （Sciaenops ocellatus,Sparus macrocephalus,and Lateolabrax japonicus） and four species of shellfish （Tegillarca granosa,Cyclina sinensis,Sinonovacula constricta,and Ostrea cucullata） that were collected downstream of electronic-waste recycling plants in Taizhou,China.A total of 24 PBDE congeners （PBDE 24） in the samples were detected.The PBDE 24 （total PBDE） ranged from 545.4 to 1688.7 ng/kg ww （wet weight）.The mean PBDE 24 concentration was 1382.6 ng/kg ww in fish and 858.1 ng/kg ww in shellfish.The lower brominated congeners were detected at relatively high concentrations in all species.The penta-products,produced from e-waste,were found at relatively low levels.A principal component analysis suggested a significant correlation among di-,tri-,tetra-,and hepta-BDEs for the three species of fish.Similarly,we found a significant correlation between mono-and tri-BDEs in the shellfish.Our results suggested that the processes of PBDE metabolism and elimination were similar in both fish and shellfish.In addition,the primary source of PBDEs appeared to be from the debromination of high brominated PBDEs.
基金supported by 973 program(No.2009CB941701)NSFC grant(No.30972508)MOE Foundation for PhD Program(No 20093234110002)
文摘Objective：To investigate the metabolites of polybrominated diphenyl ether 99（BDE-99）and its related cytochrome P450s in an in vitro system.Methods：Rat primary hepatocytes were isolated and treated with BDE-99 for 24-72 h.Metabolites were then extracted from the hepatocytes and media,and detected by GC/MS.Several mRNAs of metabolic enzymes were also extracted from the same cells and the gene expression levels were determined using quantitative real-time PCR.In addition,selected recombinant cytochrome P450s（CYPs） were expressed in a bacurovirus/sf9 system,and these were further used to explore the metabolism of BDE-99 in vitro.The parent depletion approach was used for screening the ability of CYPs to eliminate BDE-99.Results： A reductively debrominated metabolite,BDE-47,and three oxidative metabolites,2,4,5-tribromophenol,5-OH-BDE-47,and 5＇-OH-BDE-99,were identified from the BDE-99-treated rat hepatocytes,whereas no MeO metabolite was detected in the system.RT-PCR analysis showed that CYP 3A23/3A1,1A2,and 2B1/2 were induced by BDE-99.Furthermore,using the heterological expressed CYP proteins in in vitro BDE-99 metabolism experiments we found that CYP1A2 and CYP3A4 showed the highest metabolic efficiency for BDE-99,with the metabolic clearance rates of CYP1A2 and CYP3A4 being 30.3%and 27.7%,respectively.CYP1A1 and CYP2A6 displayed relatively low clearance rates,while CYP2E1 seemed not to be associated with the BDE-99 metabolism.Conclusions：In our in vitro rat primary hepatocyte metabolism system,four metabolites of BDE-99 were identified,and CYP3A4 and CYP1A2 were demonstrated to be involved in the BDE-99 metabolism.
基金Sponsored by the National Natural Science Foundation of China(Grant No.21277038)
文摘Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether( PBDE) congeners( BDE17,28,47,66,99,100,153,154,138,183,and BDE-209) were detected to state the pollution situation. The results showed that the total concentration of total PBDEs ranges from 0. 424 to 23. 0 ng / g dry weight,with the mean of 3. 02 ng / g,and the total PBDEs concentration is at relative low level compared with those worldwide. The congener profile showed that BDE-209 is the dominant congener that accounts for more than 80. 1% of total PBDEs in sediments,followed by BDE-47 and BDE-99. These profiles are consistent with a high consumption of Deca-BDEs for the brominated flame retardant market in China. The results of spatial and seasonal observations indicated that local sources,temperature variation, and hydrologic conditions are significant factors on PBDEs concentrations. Hazard quotients suggested that PBDEs pose no potential risk to benthic organisms in detected area at present.
文摘PBDEs are widely used brominated flame retardant, which are increasingly reported in the environment. Concentrations of thirteen PBDEs in a large number of channel catfish and fish feeds collected from Hubei province of China were investigated in this study. A fast isotopic dilution GC-MS method was firstly developed to simultaneously determine thirteen PBDEs in channel catfish and fish feeds in this study, and especially for the first time PBDEs in fish feeds. Pressurized liquid extraction and multi-layer silica gel column chromatography cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures, and GC and MS conditions were optimized. The limits of quantitation values of 0.25 - 5 μg·kg-1 wet weight in channel catfish were calculated for PBDEs;so did 1 - 20 μg·kg-1 wet weight in fish feeds. In addition, good repeatability and accuracy of the whole method were achieved. The established methods were therefore suitable for the simultaneous determinations of thirteen PBDEs in these samples at trace contamination levels. Using the established methods, PBDEs emerged in 10 of 180 channel catfish and 13 of 115 fish feeds, and the dominant PBDEs homologues were PBDE-28, PBDE-47, PBDE-100, PBDE-99, PBDE-154, PBDE-153 and PBDE-183. The detection rates of seven PBDEs congeners were in turn respectively 1.74%, 7.83%, 4.35%, 5.22%, 3.48%, 2.61% and 2.61% in fish feeds, and detection rates of seven PBDEs congeners were in turn respectively 1.11%, 3.89%, 2.22%, 1.67%, 1.11%, 1.11% and 1.11% in channel catfish. There was significant correlation in PBDEs between matching channel catfish and fish feeds (R2 = 0.742, P < 0.001, n = 30), suggesting that fish feeds contaminated with PBDEs possibly resulted in PBDEs residual in channel catfish through biological transfer.
文摘This review focuses on the occurrence and interactions of engineered nanoparticles(ENPs)and brominated flame retardants(BFRs)such as polybrominated diphenyl ethers(PBDEs)in water systems and the generation of highly complex compounds in the environment.The release of ENPs and BFRs(e.g.PBDEs)to aquatic environments during their usage and disposal are summarised together with their key interaction mechanisms.The major interaction mechanisms including electrostatic,van derWaals,hydrophobic,molecular bridging and steric,hydrogen andπ-bonding,cation bridging and ligand exchange were identified.The presence of ENPs could influence the fate and behaviour of PBDEs through the interactions as well as induced reactions under certain conditions which increases the formation of complex compounds.The interaction leads to alteration of behaviour for PBDEs and their toxic effects to ecological receptors.The intermingled compound(ENPs-BFRs)would show different behaviour from the parental ENPs or BFRs,which are currently lack of investigation.This review provided insights on the interactions of ENPs and BFRs in artificial,environmental water systems and wastewater treatment plants(WWTPs),which are important for a comprehensive risk assessment.
基金supported by the National Natural Science Foundation of China(Nos.21707170,21777194 and 22076052)the Natural Science Foundation of Hubei Province(No.2021CFB535)the Fundamental Research Funds for the Central Universities of South-Central MinZu University(No.CZT20019).
文摘Polybrominated diphenyl ethers(PBDEs)are widely used as brominated flame retardants,which had attracted amounts of attention due to their harmful characteristics of high toxicity,environmental persistence and potential bioaccumulation.Many chemical reductive debromination technologies have been developed for the debromination of PBDEs,including photolysis,photocatalysis,electrocatalysis,zero-valent metal reduction,chemically catalytic reduction and mechanochemical method.This review aims to provide information about the degradation thermodynamics and kinetics of PBDEs and summarize the degradation mechanisms in various systems.According to the comparative analysis,the rapid debromination to generate bromine-free products in an electron-transfer process,of which photocatalysis is a representative one,is found to be relatively difficult,because the degradation rate of PBDEs depended on the Br-rich phenyl ring with the lowest unoccupied molecular orbital(LUMO)localization.On the contrary,the complete debromination occurs easily in other systems with active hydrogen atoms as the main reactive species,such as chemically catalytic reduction systems.The review provides the knowledge on the chemical reductive technique of PBDEs,which would greatly help not only clarify the degradation mechanism but also design the more efficient system for the rapid and deep debromination of PBDEs in the future.
基金Supported by the State Key Basic Research Project (973 Project) of China (Grant No. 2003CB415002)the National Natural Science Foundation of China (Grant Nos. 40525012,20507018 and 40632012)
文摘The spatial,temporal,and vertical distributions of polybrominated diphenyl ethers(PBDEs) in water columns from the Zhujiang River Estuary were examined,and the partition behavior of PBDEs between particle and dissolved phases was investigated in the present study.The results show that the distributions of PBDEs concentrations in the water varied with the sampling seasons.The PBDEs concentrations in water samples were lower in May 2005,when the brackish water was dominant in the estuary,than in October 2005,when fresh water from river runoff dominated the estuary.The spatial distribution of PBDEs in October 2005 indicated that the river runoff was the major mode to input PBDEs to the estuary,and the concentration of PBDEs in water might be dissolved organic carbon(DOC) dependence.The spatial and vertical distributions of PBDEs in May 2005 were relatively homogeneous,and SPM was the major factor on controlling the levels of PBDEs in this sampling time.Both DOC and POC could play certain roles in determining the distribution and partition of PBDEs between particle and dissolved phases,but their effects varied with the water properties.
基金Supported by the Key Project of the National Natural Science Foundation of China (Grant No. 20737001)the National Natural Science Foundation Key Project of China (Grant No. 20737001)the Science and Technology Development Founda-tion Project of Nanjing Medical University (Grant No. 06NMUM021)
文摘Polybrominated diphenyl ether congeners (PBDEs) might activate the AhR (aromatic hydrocarbon receptor) signal transduction, and thus might have an adverse effect on the health of humans and wildlife. Because of the limited experimental data, it is important and necessary to develop structure-based models for prediction of the toxicity of the compounds. In this study, a new molecular structure representation, molecular hologram, was employed to investigate the quantitative relationship between toxicity and molecular structures for 18 PBDEs. The model with the significant correlation and robustness (r <sup>2</sup> = 0.991, q <sup>2</sup> <sub>LOO</sub> = 0.917) was developed. To verify the robustness and prediction capacity of the derived model, 14 PBDEs were randomly selected from the database as the training set, while the rest were used as the test set. The results generated under the same modeling conditions as the optimal model are as follows: r <sup>2</sup> = 0.988, q <sup>2</sup> <sub>LOO</sub> = 0.598, r <sup>2</sup> <sub>pred</sub> = 0.955, and RMSE (root-mean-square of errors) = 0.155, suggesting the excellent ability of the derived model to predict the toxicity of PBDEs. Furthermore, the structural features and molecular mechanism related to the toxicity of PBDEs were explored using HQSAR color coding.
基金supported by National Institute of Environmental Health Sciences Superfund Research Program,Grant number P42ES013648.
文摘Polybrominated diphenyl ethers(PBDEs)have been used as flame retardants in various building materials,plastic and other polymers,airplanes,electronics,etc.All or some of their congeners have been already banned in many countries,due to their persistency and adverse health effects.In this study,we are focusing on e-wastes as a source of emission of PBDEs in ambient air during reclamation processes.The ambient air particulate matter(PM)samples were collected at and near an e-waste reclamation site in Bangkok,Thailand.Results showed the presence of various homologues,viz:tri-,tetra-,penta-,hexa-,and hepta-PBDEs in both PM2.5 and total suspended particle(TSP)samples.The comparison of samples as a function of distance from the reclamation site indicated elevated levels of PBDEs in close proximity to the e-waste site.Interestingly,a shift in the congener pattern was observed with lower brominated PBDEs being more prevalent in nearby off-site samples as compared to the PM collected at the e-waste site.The total penta-PBDEs concentration is almost double in the e-waste site PM2.5 compared to the control site samples.For TSP,tetra,penta,and hepta-PBDEs congeners are at higher concentrations at the e-waste sites and its vicinity compared to reference sites.Overall,a clear trend can be observed indicating a debromination of PBDEs to more toxic tri and tetra congeners during the reclamation process and PBDEs are being translocated from treated materials to ambient air PM.BDE 30 is uniquely detected in our studies as a dominant final debromination product,that can be used as a marker of thermal e-waste activity.This work indicates potential hazards related to the reclamation of e-wastes and remediation of sites containing PBDEs.In particular,thermal treatment methods can lead to congener transformation and increased emissions of more toxic lower brominated congeners.
