Assessment of Organ chlorine Pesticide Residues In Water, Soil, Selected Vegetables And Wheat Irrigated With Downstream Akaki River, Ethiopia

Abstract

In this study the residual concentrations of sixteen organochlorine pesticides (OCPs) were analyzed in soils, water, some vegetables (cabbage, tomato, potato, beetroot, and onions) and wheat irrigated with water from the downstream catchment of the Akaki River in the Oromia regional state of Ethiopia. Sample preparation and extraction were carried out using standard procedures (quick easy cheap effective rugged and safe (QuEChERS) multi- residue extraction and clean up techniques). For vegetables and wheat, a liquid-liquid microextraction procedure was used for water and a Soxhlet extraction for soil samples and followed by gas chromatography-mass spectrometry (GC-MS) analysis. From the studied OCPs eight of them were detected in vegetables, wheat, and water and soil samples. The OCPs found in all studied samples include alpha-linden (α-HCH), delta-linden (δ-HCH) gamma-linden (γ-HCH), heptachlor (HC), heptachilorepoxide (HCE), paradichlorodiphenyldichloroethylene (p, p’DDE), dieldrin, Endrin, Para dichlorodiphenyldichloroethane (p, p’-DDD) and Para dichlorodiphenyltrichloroethane (p, p’-DDT). The concentrations of these OCPs in vegetables and wheat samples ranged from 0.11 ± 0.01µg/kg (for ES-I) 18.78 ± 0.17 µg/kg (α-HCH) in the Hechu zone cabbage and Meteli zone samples, respectively. Whereas, in water and soil samples, the detected concentrations ranged from highest at Dawaratino zone water sample gamma linden (10.88µg/L), the lowest in meteli zone water sample delta-linden (0.61(0.01) µg/kg) & highest at mekana zone soil sample endosulfansulphate (ESS) (44.73 (0.33) µg/kg), the lowest in dawara Tino zone soil sample p, p’-DDE (4.74 (0.12) µg/kg). Indeed, the concentrations of the OCPs detected in the vegetables and wheat samples analysed were observed to be at alarming levels, exceeding the maximum residue limits (MRL) set by the EU. ESS was not detected in any of beetroot and wheat samples. The presence of pesticides residues in the analyzed samples poses a significant threat to human health. Therefore, continuous monitoring is recommended so as to regulate the use of these pesticides in the study area.