Health Risk Assessment of Organochlorine Pesticide Residues in Selected Herbal Medicines Sold in Lagos State, Nigeria

The use of herbal medicines has a very long history for therapeutic purposes. However, cases of toxicological effects have been reported. The present study aims to assess the safety level of herbal medicines by monitoring the organochlorine pesticide (OCP) residues content. This study assessed the presence of seventeen organochlorine pesticide residues in twenty-seven (27) herbal medicine samples (14 liquid and 13 solid) collected from seven Local Government Area of Lagos state, Nigeria. The residues were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS) with solid phase extraction. Results showed the presence of banned OCP residues in all the selected samples at concentrations greater than the Maximum Residue limit, MRL. The Estimated Daily Intake, EDI measures the level of exposure to the pesticide residues for all the samples were found to be lower than the Acceptable Daily Intake, ADI. Health Risk Index (HRI) of all the selected samples was generally lesser than one (1) which indicates that long term exposure may not be of immediate concern to the consumers. The solid herbal medicines were found to have higher mean concentration, EDI and HRI when compared to the liquid herbal samples, suggesting that processing and preparation techniques for solid herbal medicines should be improved. The presence of the banned OCP residues in herbal medicine is, however, of public health interest and should be regularly monitored.