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
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
For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the...For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the Ya-Er Lake area . Total concentrations of PCDDs from 70 to 1.6 ×105 ng/kg dw ,median 7.9×104 ng/kg dw and of PCDFs from 1.8 to 1.8 ×104ng/kg dw ,median 9.2 ×103 ng/kg dw were measured . The internaional toxic equivalents (I-TEQ) varied from 0.14 to 8.1×10 2 ng/kg dw,median 4.1×102 ng/kg dw The PCDDs pattern showed that the concentration of OCDD was significantly higher than that of the low chlorinated congeners . The results indicated that parts of Ya-Er Lake are heavily pollutad by there chiorinated compounds. Comparison of our results with the pattern of sediments showed significant differences . The asults are of special importance bocause the pollution that affected Ya-Er Lake may spread to agricultural land and the Changjiang River.展开更多
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.
文摘For the first time in P. R. China, six locations were investigated regarding the impact of poloychlorinated dibenzo-p-dioxins (PCDs) and polychlorinated dibenzofurans (PCDFs) in contaminated sediments and soils in the Ya-Er Lake area . Total concentrations of PCDDs from 70 to 1.6 ×105 ng/kg dw ,median 7.9×104 ng/kg dw and of PCDFs from 1.8 to 1.8 ×104ng/kg dw ,median 9.2 ×103 ng/kg dw were measured . The internaional toxic equivalents (I-TEQ) varied from 0.14 to 8.1×10 2 ng/kg dw,median 4.1×102 ng/kg dw The PCDDs pattern showed that the concentration of OCDD was significantly higher than that of the low chlorinated congeners . The results indicated that parts of Ya-Er Lake are heavily pollutad by there chiorinated compounds. Comparison of our results with the pattern of sediments showed significant differences . The asults are of special importance bocause the pollution that affected Ya-Er Lake may spread to agricultural land and the Changjiang River.
