Ultrasonic destruction of pesticide contaminants in slurries

The use of high power ultrasound to destroy pesticide contaminants in sand slurries is reported. Small quantities of DDT, chlordane, atrazine, 2,4,5-T and endosulfan in solvent were added to washed, screened sand and deposited onto the sand by slow evaporation of the solvent. Fifty wt.% slurries for all five pesticides and 20 wt.% slurries of atrazine and 2,4,5-T were sonicated for periods up to 30 min and samples were withdrawn at various intervals and analysed to follow the kinetics of contaminant destruction. Seventy percent destruction of the contaminant was obtained for four of the 50 wt.% slurries with approximately 50% destruction of 2,4,5-T in 10 min of sonication whereas, in the 20 wt.% slurries of atrazine and 2,4,5-T, and 75% and 85% reduction, respectively, was obtained in 10 min. We postulate that better stirring of the slurry will improve these rates of contaminant destruction. (C) 2009 Elsevier B.V. All rights reserved.