Dicofol type DDTs-contamination is of great concern as environmental organochlorine pollutant. In the present study, dechlorination time-course ofp,p＇-DDT and p,p＇-DDE in dithionite treated waterlogged DDTs-contamin...Dicofol type DDTs-contamination is of great concern as environmental organochlorine pollutant. In the present study, dechlorination time-course ofp,p＇-DDT and p,p＇-DDE in dithionite treated waterlogged DDTs-contaminated soil, non-contaminated soil solution and citrate-bicarbonate buffer （0, 50, 100 mmol L^-1, dithionite） for 72 hrs was investigated based on residual amount of p,p＇-DDTs （p,p＇-DDT and p,p＇-DDE） analyzed by GC-ECD. The metabolites ofp,p＇-DDTs in dithionite treated non-contaminated soil solution, and citrate-bicarbonate buffer were detected by GC-MSD. The dechlorination time-course of p,p＇-DDT and p,p＇-DDE exhibited rapid dechlorination at the first 3.0 hrs, slow dechlorination after 3.0 hrs. For 50 mmol L^-1 dithionite treatments, the dechlorination ratios ofp,p＇-DDT and p,p＇-DDE were 36.42% and 35.08% respectively at 3.0 hrs. For 100 mmol L^-1 dithionite treatments, the dechlorination ratios of p,p＇-DDT and p,p＇-DDE were 58.62% and 57.39% respectively at 3.0 hrs in DDTs-contaminated soils. Significant differences of dechlorination ratio were also confirmed in dependence on dithionite concentrations, reaction systems and the chemical structure of DDTs. The dechlorination ratio ofp,p＇-DDT/DDE increased with the increasing of dithionite concentrations irrespective of reaction systems. Dithionite-induced dechlorination ratio of p,p＇-DDT was higher than that of p,p＇-DDE. The p,p＇-DDD （1,1-dichloro-2,2-bis（4-chlorophenyl）-ethane）, p,p＇-DDE and p,p＇-DDMU （1-chloro-2,2-bis（4-chloropheny）-ethylene） were identified to be metabolites ofp,p＇-DDT in buffer and non-contaminated soil solution, however, no metabolites ofp,p＇-DDE treated by dithionite were detected. The possible pathways explaining the dechlorination of p,p＇-DDT and p,p＇-DDE by dithionite were also proposed. Dithionite could be used to develop an effective and fast remediation option for DDTs-contaminated soils and sediments.展开更多
The levels of 13 organochlorine pesticides （OCPs） in sediments of Honghu Lake were investigated in order to evaluate their potential pollution and risk. A total of 30 sediment samples from 15 sampling locations were...The levels of 13 organochlorine pesticides （OCPs） in sediments of Honghu Lake were investigated in order to evaluate their potential pollution and risk. A total of 30 sediment samples from 15 sampling locations were collected in the lake during July, 2005. The total concentrations in top-sediment samples and sub-sediment samples ranged from 3.52 ng/g to 69.71 ng/g and 0.49 ng/g to 97.37 ng/g, respectively. The HCH isomers, DDT congeners, aldrin, trans-chlordane, cis-chlordane, heptachlor and endrin-ketone were significant in these samples. The concentrations of OCPs in the lakeshore sediments were higher than those sampled across the lake. Distribution of HCHs, DDTs and other OCPs were different, indicating their various contamination sources. Composition analysis in sediments indicated recent usage or discharge of lindane, dicofol into the lake.展开更多
A soil survey was conducted in Zhangzhou City, an important agricultural region in south of the Fujian Province, China. 93 surface soil samples were collected in the paddy fields, vegetable lands, orchards and tea pla...A soil survey was conducted in Zhangzhou City, an important agricultural region in south of the Fujian Province, China. 93 surface soil samples were collected in the paddy fields, vegetable lands, orchards and tea plantations from Zhangzhou City. An additional soil profile was sampled in a paddy field as previous research had indicated high concentrations of organochlorine pesticides （OCPs） in the paddy fields. Dichlorodiphenyltrichloroethanes （DDTs） ranged from 0.64 78.07 ng g-1 dry weight and hexachlorocyclohexanes （HCHs） ranged from 0.72-30.16 ng g-1 dry weight in the surface soil of the whole study region. Ratios of a-HCH/-γ-HCH 〈 4 and o,p′-DDT/p,p′-DDT 〉 1 in all soil samples suggested that lindane and dicofol were widely applied in this region in the past. Concentrations of HCHs and DDTs in soils from the four land use types followed the orders： paddy fields 〉 vegetable lands 〉 tea plantations 〉 orchards and tea plantations 〉 orchards 〉 paddy fields 〉 vegetable lands, respectively. Analyses of the data showed no correlation （r 〈 0.1） between elevation and OCPs contents in paddy fields, orchards and vegetable lands, indicated no significantly different features in distribution of HCHs and DDTs in the soils from low lying plains and mountains and the unsystematic usage of OCPs, and highlighted the fragmented nature of agricultural production in Zhangzhou, as well as the reemission of OCPs from the soils, where high OCPs concentrations were found, in Longhai of Zhangzhou. In addition, no obvious relationship between the OCPs and total organic carbon （TOC） （r 〈 0.3） was observed in the soil profile. The mean contribution of dicofol in total DDTs was 66% in the whole Zhangzhou region. The approximate burdens of HCHs and DDTs in the surface layer of 0-20 em were 0.44 and 1.55 t, respectively. The storage of both HCHs and DDTs in soil surface layer （0-20 cm） accounts for 40% burden of the soil layer of 0 50 cm （1.10 t HCHs and 3.87 t DDTs）, in which the highest concentrations of OCPs were observed in soil profile.展开更多
基金Acknowledgments This research was jointly supported by National Science Foundation of China （No. 20777092）, the ministry of Science and Technology of China （2007CB407304） and Natural science foundation of Zhejiang province of China （Y307025）.
文摘Dicofol type DDTs-contamination is of great concern as environmental organochlorine pollutant. In the present study, dechlorination time-course ofp,p＇-DDT and p,p＇-DDE in dithionite treated waterlogged DDTs-contaminated soil, non-contaminated soil solution and citrate-bicarbonate buffer （0, 50, 100 mmol L^-1, dithionite） for 72 hrs was investigated based on residual amount of p,p＇-DDTs （p,p＇-DDT and p,p＇-DDE） analyzed by GC-ECD. The metabolites ofp,p＇-DDTs in dithionite treated non-contaminated soil solution, and citrate-bicarbonate buffer were detected by GC-MSD. The dechlorination time-course of p,p＇-DDT and p,p＇-DDE exhibited rapid dechlorination at the first 3.0 hrs, slow dechlorination after 3.0 hrs. For 50 mmol L^-1 dithionite treatments, the dechlorination ratios ofp,p＇-DDT and p,p＇-DDE were 36.42% and 35.08% respectively at 3.0 hrs. For 100 mmol L^-1 dithionite treatments, the dechlorination ratios of p,p＇-DDT and p,p＇-DDE were 58.62% and 57.39% respectively at 3.0 hrs in DDTs-contaminated soils. Significant differences of dechlorination ratio were also confirmed in dependence on dithionite concentrations, reaction systems and the chemical structure of DDTs. The dechlorination ratio ofp,p＇-DDT/DDE increased with the increasing of dithionite concentrations irrespective of reaction systems. Dithionite-induced dechlorination ratio of p,p＇-DDT was higher than that of p,p＇-DDE. The p,p＇-DDD （1,1-dichloro-2,2-bis（4-chlorophenyl）-ethane）, p,p＇-DDE and p,p＇-DDMU （1-chloro-2,2-bis（4-chloropheny）-ethylene） were identified to be metabolites ofp,p＇-DDT in buffer and non-contaminated soil solution, however, no metabolites ofp,p＇-DDE treated by dithionite were detected. The possible pathways explaining the dechlorination of p,p＇-DDT and p,p＇-DDE by dithionite were also proposed. Dithionite could be used to develop an effective and fast remediation option for DDTs-contaminated soils and sediments.
文摘The levels of 13 organochlorine pesticides （OCPs） in sediments of Honghu Lake were investigated in order to evaluate their potential pollution and risk. A total of 30 sediment samples from 15 sampling locations were collected in the lake during July, 2005. The total concentrations in top-sediment samples and sub-sediment samples ranged from 3.52 ng/g to 69.71 ng/g and 0.49 ng/g to 97.37 ng/g, respectively. The HCH isomers, DDT congeners, aldrin, trans-chlordane, cis-chlordane, heptachlor and endrin-ketone were significant in these samples. The concentrations of OCPs in the lakeshore sediments were higher than those sampled across the lake. Distribution of HCHs, DDTs and other OCPs were different, indicating their various contamination sources. Composition analysis in sediments indicated recent usage or discharge of lindane, dicofol into the lake.
基金Supported by the National Natural Science Foundation of China(No.41073070)the Research Fund for the Doctoral Program of Higher Education of China(No.20090145110004)
文摘A soil survey was conducted in Zhangzhou City, an important agricultural region in south of the Fujian Province, China. 93 surface soil samples were collected in the paddy fields, vegetable lands, orchards and tea plantations from Zhangzhou City. An additional soil profile was sampled in a paddy field as previous research had indicated high concentrations of organochlorine pesticides （OCPs） in the paddy fields. Dichlorodiphenyltrichloroethanes （DDTs） ranged from 0.64 78.07 ng g-1 dry weight and hexachlorocyclohexanes （HCHs） ranged from 0.72-30.16 ng g-1 dry weight in the surface soil of the whole study region. Ratios of a-HCH/-γ-HCH 〈 4 and o,p′-DDT/p,p′-DDT 〉 1 in all soil samples suggested that lindane and dicofol were widely applied in this region in the past. Concentrations of HCHs and DDTs in soils from the four land use types followed the orders： paddy fields 〉 vegetable lands 〉 tea plantations 〉 orchards and tea plantations 〉 orchards 〉 paddy fields 〉 vegetable lands, respectively. Analyses of the data showed no correlation （r 〈 0.1） between elevation and OCPs contents in paddy fields, orchards and vegetable lands, indicated no significantly different features in distribution of HCHs and DDTs in the soils from low lying plains and mountains and the unsystematic usage of OCPs, and highlighted the fragmented nature of agricultural production in Zhangzhou, as well as the reemission of OCPs from the soils, where high OCPs concentrations were found, in Longhai of Zhangzhou. In addition, no obvious relationship between the OCPs and total organic carbon （TOC） （r 〈 0.3） was observed in the soil profile. The mean contribution of dicofol in total DDTs was 66% in the whole Zhangzhou region. The approximate burdens of HCHs and DDTs in the surface layer of 0-20 em were 0.44 and 1.55 t, respectively. The storage of both HCHs and DDTs in soil surface layer （0-20 cm） accounts for 40% burden of the soil layer of 0 50 cm （1.10 t HCHs and 3.87 t DDTs）, in which the highest concentrations of OCPs were observed in soil profile.
