Analysis of Organ chlorine Pesticides Residues in Onion and Tomato Samples from Open Market of Selected Towns in Jimma Zone, Ethiopia

Abstract

Pesticides are applied worldwide to a broad variety of crops to control pests. Different studies in Ethiopia showed that food products are contaminated with pesticides and banned pesticides are still being used illegally in the agricultural sector. However, wide uses of these chemicals could result in food and environmental contamination. This document objectively presents the results of a study on the determination of organochlorine pesticides (OCPs) residues in tomato and onion samples collected from selected towns of the Jimma zone. The method used was a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method followed by gas chromatography-mass spectrometry (GC-MS) for analysis. The method was validated for linearity, limit of detection (LOD), limit of quantification (LOQ), and recovery. The results for method validation showed that the method was linear over the concentration range of 5-50 ppb for all eight pesticides tested, with R2 values greater than 0.992. The LOD values for the tested pesticide ranged from 0.138 μg/kg for P,P'-DDE to 2.400μg/kg for p,p-DDT. LOQ values ranged from 0.460 μg/kg for p,p-DDE to 8.320 μg/kg for P,P'-DDT. The obtained recovery values ranged from 74.84% –109.45% except the recoveries of Beta BHC with 67.82%. While most organochlorine pesticides (OCPs) in onion and tomato samples fell under European Union (EU) and Codex standards, several exceeded limits. Methoxychlor and P,P'-DDT in onions, and Methoxychlor, P,P'-DDT, α-BHC, and δ-BHC in some tomatoes, were detected above permissible levels. Specific OCPs were not detected in certain samples including Aldrin in Meki Tomato(Mek-T), Gamma-chlordane in Agaro Tomato(Ag-T), and P,P'-DDE in Gera Tomatoes(Ger-T).Organochlorine pesticides contamination varied across samples. Among tomatoes, Gera had the highest total OCPs levels (37%), followed by Agaro(34.34%) and Meki(28.55%). Similarly, Sire onions(SrO) topped the list (28%) compared to Minjer(25.16%), Shewa robit(25.10%), and Sudan Onion(22.25%).In conclusion, most of the samples of tomatoes and onions analyzed in this study contained OCP residues and therefore its consumer health risk assessment is important.