Quantitative analysis of pesticides in vegetables: A study on tomatoes and onions from Ethiopian farms

Abstract

Vegetables are crucial for a healthy diet, but they can be exposed to pesticides throughout the growing process. This study investigated pesticide residues in tomatoes and onions using the QuEChERS extraction method and gas chromatography with an electron capture detector (GC-ECD). Samples from Ziway, Shewa Robit, Majete, and Meki regions were analyzed for pesticide residues, including organophosphates (OPPs), organochlorines (OCPs), and synthetic pyrethroids. Calibration curves demonstrated linearity (r² ≥ 0.9962), and recoveries ranged from 81–114 %, indicating analytical precision and accuracy. Findings showed high pesticide levels, especially those of malathion (112–286 µg/kg) and chlorpyrifos (53–153 µg/kg), with some values surpassing the FAO/WHO and European Union maximum residue limits (MRLs), even if the majority of pesticides were at safe levels. Pesticide residues in tomatoes were below MRLs, while chlorpyrifos and malathion levels in onions surpassed these limits, presenting health risks and impacting market access. The report emphasizes the necessity of strict pesticide control and ongoing oversight to safeguard public health and promote agricultural exports.