Abstract
In this work the concentration of some selected pesticides such as aldrin, dialdrin, BHC, diazinon, DDT, 4,4-DDE and heptachlor were investigated in water and khat samples that were collected from five different sites. The pesticides were extracted using liquid-liquid and solid phase extraction technique and analyzed by GC-ECD. The recovery test, linearity cure and extraction efficiency were tested by using standard pesticide samples. The highest concentration of pesticide obtained in water samples is diazinon in WS 2 (0.0698mg/L), and the lowest concentration is heptachlor in WS 3 (0.0006mg/L). The highest and lowest concentrations of pesticides obtained in Khat samples are diazinon in KS 1 (0.0323mg/L) and KS 3 (0.0001mg/L) respectively. The concentration of diazinon and four isomers of BHC detected in each water sample are higher than the recommended limits set by WHO which shows contamination of the lake water. Diazinon and DDT levels in KS 1 (0.0323mg/L), KS 2 (0.0293mg/L) and KS1 (0.0134mg/L), KS 2 (0.0173mg/L) respectively are above the maximum residue level. Keywords: concentration, DDT, diazinon, extraction, heptachlor DOI : 10.7176/CMR/11-3-03 Publication date :March 31 st 2019
Highlights
The use of chemicals in modern agriculture has significantly increased productivity
The result of the recovery test indicates that most of them are in the range of good recovery (70-120%), except dialdrin
The highest concentration of pesticide obtained in water sample is diazinon in WS2 (0.0698), and the lowest concentration is Heptachlor in WS3 (0.0006)
Summary
The use of chemicals in modern agriculture has significantly increased productivity. It has significantly increased the concentration of pesticides in food and in our environment, with associated negative effects on human health. The extent of the use of pesticides, and their mode of application including their abuse especially in agriculture have been of much concern to environmental scientists (Essumang et al, 2009). Pesticides are mainly sprayed on agricultural fields such as cereal crops and vegetables. Farmers in Eastern Hararge Zone use different types of pesticides for crop and Khat cultivation in different seasons. Organochlorine pesticides are very persistent, bioaccumulative and toxic, and they can find their way into an adjacent water course such as the lakes via soil run-off and leaching
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