Bioaccumulation and Distribution of Heavy Metals in Agricultural Plants Cultivated Near the Itakpe Iron Mine, Nigeria

Abstract

Heavy metal accumulation in plants is of importance due to toxicity effects in humans and other biota. 
Crop plants were sampled around Itakpe mine, Okene, Nigeria for the determination of the heavy metals 
cadmium (Cd), copper (Cu), magnesium (Mg), nickel (Ni), lead (Pb) and zinc (Zn) using Flame Atomic 
Absorption Spectroscopy. Crop plants samples were collected during the dry and rainy seasons and 
digested with 4:1 mixture of HNO3 and HClO4. Recovery studies gave 80-120 % for crop plants. The 
average mean concentration of metallic levels in crop plants were 0.07±0.01, 0.14±0.10, 0.02±0.01, 
0.09±0.01, 0.06±0.02, 0.25±0.13 g/g. The heavy metal concentrations of crops grown on control soil were 
relatively lower than those in the Itakpe mining site soil. The observed concentrations of heavy metals in 
the studied plants were below the FAO/WHO limit guideline for food. The presence of Zn and Cu in plants 
and the higher level of metals observed in the mining site farm crops compared with the control farm 
show that agrochemicals and mining contribute to the metallic levels in the Itakpe mining environment.