Effectiveness comparison of different solvents in organochlorine pesticide contaminated soil flushing

Key words: 
• organochlorine pesticides(OCPs) /
• soil flushing /
• removal efficiencies /
• organic solvents /
• surfactant

Abstract: A flushing investigation of sixteen kinds of solvents (dichloromethane， acetone， ethyl acetate， petroleum ether， hexane， methanol， ethanol， propanol， isopropanol， rhamnolipid， hydroxypropyl-β- cyclodextrin， sodium dodecyl sulfate， SDS， SDBS， Tween 80 and Triton 100) was conducted to select an optimum solvent for HCHs and DDTs， and chlordane and mirex-polluted soil flushing. Results showed that in HCHs and DDTs contaminated soil， ethyl acetate is the best eluent with removal efficiencies of 87.6% and 86.9% for HCHs and DDTs， respectively. The removal efficiencies of the other organic solvents ranged between 61.6% and 87% for HCHs and DDTs， but the removal efficiencies of surfactants were less than 4% for HCHs and DDTs. Organic solvents were better than surfactants in HCHs and DDTs polluted soil flushing. This phenomenon also occurred in chlordane and mirex-polluted soil. For mirex， the removal efficiencies of organic solvents were about 80% with the exception of propanol (63.5%). For chlordane， the removal efficiencies of organic solvents were more than 70% with the exceptions of petroleum ether (59.6%)， hexane (49.3%) and propanol (42%).The removal efficiencies of chlordane for Tween 80， cyclodextrin， Triton X-100 and rhamnolipid were 54%，20%， 12.8% and 12.2%， respectively， and the other surfactants’ were lower than 1%. And the removal efficiencies of mirex were 29.6% for Tween 80，12.4% for Triton X-100， 5.7% for rhamnolipid. Therefore， it is concluded that organic solvents like ethyl acetate， acetone and ethanol， can act as better flushing solvents in organochlorine pesticide polluted soil in the light of removal efficiencies.