Heavy Metals Contamination of Some Food Materials from Markets in South Eastern Nigeria

Abstract

This research work aimed at assessing the metal composition of the cotyledons of Citrullus colocynthis (egusi) and Irvingia wombolu (ogbono) as well as cassava chips sold in open markets in the five states of the South-Eastern Nigeria. These food materials were sampled from 135 stores and markets in three waves (Wet season, Harmattan and Dry season) between February, 2015 and March, 2016 in each of the five states in south eastern Nigeria (Enugu, Anambra, Imo, Abia and Ebonyi). The food materials were analyzed for Zinc, Lead, Copper and Iron using the Atomic Absorption Spectroscopy (AAS) method. The concentrations of these metals were not higher than the maximum permissible limit set by NAFDAC in Nigeria except for Lead in Enugu State ((0.042±0.068 mg/g). The highest quantity of Lead was detected in Citrullus colocynthis (0.039±0.006 mg/g) while the least concentration was detected in Cassava chips (0.009±0.005 mg/g). Lead was detected in samples collected across all the seasons (Wet season, Dry season and Harmattan). The high concentration of Lead in the sampled food materials from Enugu state across all the waves of sample collection that violated the permissible limits of lead set by WHO and NAFDAC is of public health concern. Lead exposure has been shown to cause severe health challenges thus regular monitoring of these toxic heavy metals from foods sold in markets is essential, to prevent their excessive build-up in the food chain. The inference of this study reveals that these food materials sold in the open market are not completely safe for consumption as a result of lead contamination due to poor handling and processing. Findings from this study will be of great help to all stakeholders in this area of interest such as researchers and environmental regulators, relevant government agencies saddled with the responsibility of ensuring the safety of foods consumed in Nigeria.