Laboratory-Scale Ozonation of Water Contaminated with Trace Pesticides

Trace amounts of 39 kinds of pesticide in river water and tap water were determined by a gas Chromatography/mass spectrometry with a selected ion monitoring (GC/MS-SIM). Eighteen pesticides were detected at ng/L levels in the river water samples, and 11 in tap water. The river water was treated with laboratory-scale oxidation processes using ozone and ozone-hydrogen peroxide, and the efficiencies of pesticide removal by the oxidation processes were evaluated. Although several pesticides such as dichlorvos, simazine and atrazin remained in river water after the treatment with ozone alone, the ozone treatment in combination with hydrogen peroxide improved their decompositions. Detection of 11 kinds of pesticides in tap water indicates that those pesticides are slightly removed by the conventional drinking water treatment.