Multi-residue Analysis of Organochlorine Pesticides in Cocoa Beans (Theobroma cacao) and Soils from Ondo, Nigeria

Abstract

Organochlorine pesticides (OCPs) residues were determined in a total of 160 samples comprising of cocoa beans and soil collected from four major cocoa farms in Ondo, Nigeria. The residues were extracted with dichloromethane, cleaned up by column chromatography and analysed with Gas Chromatography-Electron Capture Detector (GC-ECD). In the analysed cocoa samples, endrin and endosulfan I had the highest incidence of occurrence of 93% and 89%, respectively while lindane and heptachlor had the least occurrence of 19%. High incidences of occurrence in the soil samples were observed in endrin (93%) and endosulfan I (94%) while the least occurrence was α-HCH (13%). The total residual concentrations of the OCPs were higher in the cocoa samples compared to the soil samples. The mean residual levels of HCHs (α, β, δ) aldrin, dieldrin, endrin and endosulfan I and cis-permethrin in the cocoa samples were above Maximum Residual Limits (MRL) established by WHO/FAO while aldrin, dieldrin, endrin, endosulfans in the soil sample analysed were above MRL established by Netherlands. Bioaccumulation factor > 1 was recorded in most of the cocoa samples from the different farms especially for endrin, dieldrin, endosulfan I and trans-permethrin. This gives cause for concern considering the adverse health hazards pose by these pesticides.