Organochlorine Pesticide Residue Levels and Potential Human Health Risks in Kolanuts from Selected Markets in Osun State, Southwestern Nigeria

Abstract

Organochlorine Pesticide (OCP) residue were qualitatively and quantitatively determined using Gas Chromatography-Electron Capture Detector (GC-ECD) and their potential health risks assessed in kolanut (Cola nitida) samples from selected markets in Osun State, Southwestern Nigeria. Health risk estimates were analyzed using Estimated Average Daily Intake (EADI) and Hazard Index (HI) with risk categorized for non-carcinogenic health effects. A total of 17 OCPs were identified and their residues were detected in all the kolanut samples analyzed. The results showed that the mean concentration of p,p-DDE, Dieldrin, Endosulfan, and Lindane were 0.480±1.106 mg kg-1, 0.310±0.442 mg kg-1, 0.243±0.144 mg kg-1 and 0.044±0.041 mg kg-1 respectively.  Among the OCPs analyzed, p,p-DDE and α-HCH were the dominant isomers for DDT and HCH, respectively. The Principal Component Analysis (PCA) results showed that out of the 17 OCPs detected, p,p-DDE, endosulfan sulphate, dieldrin, and methoxychlor were major compounds primarily contributing to variation in the detected OCPs residues in the kolanut samples. The concentrations of all the analyzed OCP observed in the nuts were found to be higher than the recommended maximum residual limits (MRLs), the maximum concentration of a pesticide residue legally permitted to remain in food after it has been treated with the pesticide. The percentage above the MRL ranges from 28 to 100%. The analysis of health risk estimates revealed that the HI values for γ-HCH (1.907), heptachlor (15.700), aldrin (20.3), dieldrin (40.3) and endrin (2.925) were above value of 1 suggesting a potential for chronic toxicity to the regular consumers of kolanuts obtained from these markets. The current situation could be therefore considered a serious public health problem. Hence, a continuous monitoring of pesticide residues in kolanuts and a tighter regulation of pesticides used on stored produce are recommended.