Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were mea...Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.展开更多
The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-poly...The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.展开更多
Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G＊ level by density functional theory （DFT） method. The structural parameters were obtained and significant correlation betwee...Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G＊ level by density functional theory （DFT） method. The structural parameters were obtained and significant correlation between the C1 substitution position and some structural parameters was found. Consequently, the number of C1 substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and -lgSw of all PCDD congeners. The two models achieved in this work contain two variables （Na and Nβ）, of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values are all large. The variation inflation factors （VIF） of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and -lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods.展开更多
Based on the Industrial Source Complex Short-Term Version 3 (ISCST3) model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) ...Based on the Industrial Source Complex Short-Term Version 3 (ISCST3) model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) of agricultural soil, within a radius of 3 km from a municipal solid waste incinerator (MSWI) plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent (I-TEQ) values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and I-TEQ values were generally lower than their observations, and that the higher the degree of under-estimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 km of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra-and penta-chlorinated dioxins.展开更多
采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重...采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重金属,但与飞灰中二口恶英的含量并不存在显著的关系。流化床炉与炉排炉布袋除尘器飞灰中二口恶英同系物分布特性不同。飞灰中二口恶英的主要同系物是1,2,3,4,6,7,8 HpCDD(heptachlorinateddibenzo p dioxin),1,2,3,4,6,7,8 HpCDF(heptachlorinateddibenzofuran)和OCDD(octachlorinateddibenzo p dioxin),PCDFs(polychlorinateddibenzofurans),TEQ(toxicequivalencequantity)高于PCDDs含量。初步研究表明,炉排炉飞灰中二口恶英总量及毒性当量(TEQ)大于流化床炉飞灰。展开更多
基金supported by National Research Program (No. 2003CB415005)"Youth Chen-Guang Project" of Wuhan Bureau of Science and Technology (No. 200750731259).
文摘Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.
基金TheNationalKeyBasicResearchFoundationofChina (No .G1 9990 4 571 1 )
文摘The theoretical linear solvation energy relationship(TLSER) approach was adopted to predict the aqueous solubility and n -octanol/water partition coefficient of three groups of environmentally important chemicals-polychlorinated biphenyls(PCBs), polychlorinated dibenzodioxins and dibenzofurans(PCDDs and PCDFs). For each compound, five quantum parameters were calculated using AM1 semiempirical molecular orbital methods and used as structure descriptors: average molecular polarizability(α), energy of the lowest unoccupied molecular orbit( E _ LUMO ), energy of the highest occupied molecular orbit( E _ HOMO ), the most positive charge on a hydrogen atom( q _+), and the most negative atomic partial charge( q _-) in the solute molecule. Then standard independent variables in TLSER equation was extracted and two series of quantitative equations between these quantum parameters and aqueous solubility and n -octanol/water partition coefficient were obtained by stepwise multiple linear regression(MLR) method. The developed equations have both quite high accuracy and explicit meanings. And the cross-validation test illustrated the good predictive power and stability of the established models. The results showed that TLSER could be used as a promising approach in the estimation of partition and solubility properties of macromolecular chemicals, such as persistent organic pollutants.
基金the Natural Science Foundation of Zhejiang Province (No. X206955)Zhejiang Medical and Health Research Fund (No. 2007A047)the Education Bureau of Zhejiang Prov-ince (No. N20080181), China
基金This work was supported by the National Natural Science Foundation of China (No. 20737001)(2003CB415002)China Postdoctoral Science Foundation (No. 2003033486)
文摘Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G＊ level by density functional theory （DFT） method. The structural parameters were obtained and significant correlation between the C1 substitution position and some structural parameters was found. Consequently, the number of C1 substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and -lgSw of all PCDD congeners. The two models achieved in this work contain two variables （Na and Nβ）, of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values are all large. The variation inflation factors （VIF） of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and -lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods.
基金Project (Nos. X506312 and X206955) supported by the NaturalScience Foundation of Zhejiang Province, China
文摘Based on the Industrial Source Complex Short-Term Version 3 (ISCST3) model, a simplified modeling approach was developed to predict concentrations of congeners of polychlorinated-p-dioxins and dibenzofurans (PCDD/Fs) of agricultural soil, within a radius of 3 km from a municipal solid waste incinerator (MSWI) plant after its 4-year operation in Hangzhou, China. Comparisons were made between the measured and estimated congener-specific concentrations and the international-toxic equivalent (I-TEQ) values of soil samples with respect to distance from the stack. The results indicate that the predictions of soil PCDD/F concentrations and I-TEQ values were generally lower than their observations, and that the higher the degree of under-estimation seems, the greater the further downwind one gets. Nevertheless, most of the predictions were in good agreement with the trend of measured ones and were within a factor of ten for samples located within 1 km of the plant. Besides, analysis of contributions of various deposition pathways confirms that in addition to wet particle deposition, the dry gaseous deposition is essential for realistic prediction of PCDD/F depositions to soil, especially for tetra-and penta-chlorinated dioxins.
文摘采用高分辨色谱/低分辨质谱联机分析了不同炉型垃圾焚烧炉布袋除尘器飞灰中的二口恶英分布特性。结果表明,燃料组成及飞灰中氯含量对飞灰中二口恶英的浓度均有影响。飞灰中氯含量与灰中的二口恶英含量成正比关系。尽管飞灰中含有大量重金属,但与飞灰中二口恶英的含量并不存在显著的关系。流化床炉与炉排炉布袋除尘器飞灰中二口恶英同系物分布特性不同。飞灰中二口恶英的主要同系物是1,2,3,4,6,7,8 HpCDD(heptachlorinateddibenzo p dioxin),1,2,3,4,6,7,8 HpCDF(heptachlorinateddibenzofuran)和OCDD(octachlorinateddibenzo p dioxin),PCDFs(polychlorinateddibenzofurans),TEQ(toxicequivalencequantity)高于PCDDs含量。初步研究表明,炉排炉飞灰中二口恶英总量及毒性当量(TEQ)大于流化床炉飞灰。
