Determination of Selected Pesticide Residues in Diga Water Reservoir, Eastern Wollega Zone, Ethiopia

Abstract

This study aimed to assess the status of diazinon, chlorothalonil, Malathion and chloropyrifos in Diga water reservoir, located in Diga district, Eastern Wollega Zone, Ethiopia. It serves as Nekemte City municipal tap water reservoir. Salting-out assisted liquid-liquid extraction (SAALE) was used for extraction and/or preconcentration of the target analytes before their determination by gas chromatography mass spectrometry (GC-MS). The method showed acceptable linearity (R2) in the range of 0.996 to 0.999. The limit of detection (LOD) of the method ranged from 1.38 to 4.92 μg L−1and limit of quantification (LOQ) ranged from 4.60 to 16.40 μg L−1. The relative recovery ranged from 80.34 % to 100.32%. Analysis of the collected real samples indicates that the water samples were not polluted with residues of diazinon, chlorothalonil, Malathion and chlorpyrifos or contain below the LOD of the method.