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
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.
