Assessment of Essential and Non-Essential Metals in Commonly Consumed Grains in Kogi State, North Central, Nigeria

Abstract

Abstract This study assessed the concentration of essential and non-essential metals in commonly consumed grains in Kogi State, Nigeria. Four (4) grains; rice (Oryza sativa), maize (Zea mays), millet (Panicum miliaceum) and beans (Phaseolus vulgaris) were collected from major sale points in selected Local Governments Areas (LGAs) across the three Senatorial Districts of Kogi State, Nigeria. The concentrations of the metals (Zn, Cu, Mn, Fe, Pb, Cd and Cr) were analyzed using an Atomic Absorption Spectrometer (AAS solar 969 Unican series) and subsequently compared to the FAO/WHO MPLs (Maximum Permissible Limits). Results of the analysis showed that the essential and non-essential metals were detected in the grains (rice, maize, millet and beans) sourced from the three (3) senatorial districts of Kogi State in varying concentrations. All the essential metals were present in the grains at concentrations below their MPLs while some of the non-essential metals were present at concentrations above their MPLs. The major contaminant of rice and millet was Cd. Cd was detected in rice and millet samples in a number of LGAs across the Senatorial Districts at concentrations above their PMLs. Pb was also present in rice and millet samples from some LGAs at concentrations above its MPL. For maize and bean samples, Cd and Pb were the only metals detected in one LGA in Kogi West Senatorial District at concentrations above their MPLs. The other non-essential metal assessed- Cr was not detected in majority of the grains but below its MPL in samples where it was detected. Cd and Pb therefore, are the major contaminants of grains consumed in Kogi State as revealed by this study. Accumulation of these non-essential metal is a major public health concern. We therefore, recommend regular monitoring of grains and other foods sold within Kogi State and Nigeria at large.