Effect of Conventional and Household Water Treatment Technologies on Pesticide Residues in Drinking Water, Southwestern, Ethiopia

Abstract

Water resources have been contaminated by pesticides due to the different activities of human beings. From different studies advanced water treatment systems can eliminate these chemical pesticides while conventional and household treatment technologies are not well studied. The main aim of the present study is to determine the effect of conventional and household water treatment technologies on pesticides residue in drinking water. Water samples were collected from Gibe River (intake point) for Jimma conventional water treatment plant, from each treatment process, and from distribution system. To determine the effect of household water treatment process (solar disinfection and boiling) pesticides were spiked into distilled water then passed through solar disinfection (SODIS) and boiling. The extraction of samples was conducted by following low density based dispersive liquid-liquid micro extraction procedure. The result of the study revealed that almost all studied pesticides (p´p-DDD, p´p-DDE, p´p-DDT, γ-Chlordane, dimethachlor, lindane, heptachlor, cypermethrin and deltamethrin) except o´p-DDT were detected in water samples. The percent reduction of pesticide residue after post chlorination by conventional water treatment ranges from 11.7% (p´p-DDD) to 97.29% (Dimethachlor) and percent reduction of pesticide residue by SODIS and boiling ranges from 2.31% (o´p-DDT) to 54.45% (Cypermethrin) and 27.13% (γ-Chlordane) to 38.9%(p´p-DDE) respectively. This indicates the treatment technologies are important for the reduction of pesticides in water. Treatment technologies improvement is necessary to allow further removal of pesticides.