Assessment of soil heavy metal pollution in the coal mining region of Ugiamwen farmland, Uhunmwonde, Edo State, Nigeria

Exploration of coal over the past years for economic improvement has led to soil degradation, heavy metal contamination, loss of crops and vegetation and threat to existence of biota. Heavy metal contamination from coal mining processes poses significant agricultural and environmental threats due to concentration and accumulation of toxic metals in the soil. This study investigated the concentrations of heavy metals such as Lead (Pb), Copper (Cu), Chromium (Cr), Arsenic (As) and Cadmium (Cd) in soil obtained from mining area of Ugiamwen farmland using the atomic mass spectrophotometry (AAS). Soil samples were collected from six sampling points with three replicates each within the Coal Mining Soil (CMS), adjacent Farmland Soil (FS) and control soil. Control soil was collected 200m away from the mining area, where no form of mining operation was done. The concentrations of Pb, Cr, Cu and As ranged from 0.120-2.700 mg/kg, 0.246-2.213 mg/kg, 4.950-132.7 mg/kg and 0.486-3.870 mg/kg, respectively. Cadmium was below detection limits in all soil samples analyzed.Mean and standard deviation were calculated, the data obtained was subjected to one-way analysis of variance. Signiant difference in mean values was differentiated with Duncan’s multiple range test (DMRT) at P≤0.05. The increase in heavy metal concentrations was linked to the leaching of wasted coal materials, use of explosive devices employed during the mining activities and emissions from heavy duty mining equipment. Findings obtained from this study confirmed the presence of heavy metal pollution in the mining area highlighting agricultural and environmental implications accompanied with the activities of coal mining.