INVESTIGATINGHERBICIDES AND INSECTICIDESRESIDUESIN TWO COMMON LEAF VEGETABLES SOLD IN AKURE, NIGERIA

Abstract

Vegetables are valuable sources of vitamins, minerals and dietary fibre. They are major components of Nigerian diets as in other parts of the world. The use of herbicides and insecticides in crop production had led to the contamination of crops with pesticide residues. Vegetables are not left out of the crops so contaminated and this could be of high public health risk. This study investigated the incidence and levels of herbicides and insecticides residues in fluted pumpkin leaves (Telfairia occidentalis) and green amaranth (Amaranthus hybridus) sold in Akure, Nigeria. The vegetables were purchased from four major markets and two vegetable farms in Akure. Soil samples from the two farms were also investigated for herbicides and insecticides residues. The pesticide residues were identified and quantified using gas chromatography. One herbicide and a minimum of nine insecticides (organophosphates, organochlorides and pyrethroids) residues were detected at various levels in the vegetable samples obtained from major markets andfarms. Amongst the detected pesticide residues are atrazine (herbicide) and dichlorvos, mevinphos, DDT, DDD, lindane, BHC, heptachlor, endosulfan, chlorothalonil, aldrin, dieldrin, endrin, lambda-cyhalothrin and permethrin (insecticides). Some of the detected residue levels in the vegetables were higher than the recommended Maximum Residue Limits (MRL). All the pesticide residues detected in the vegetables were also detected in the soils from the two farms. The insecticides residues levels in the soils were higher than for the vegetables. However, atrazineresidue (an herbicide) was higher in the vegetables than in the soil. The occurrence and levels of insecticides residues were higher for fluted pumpkin leaves than green amaranth. Farmers should therefore avoid the use of pesticides on fluted pumpkin farms.