Evaluation of Heavy Metal Pollution Index in Soil around Metal Workshops in Potiskum, Yobe State, Nigeria

Abstract

This study investigates the impact of metal workshop on the environment due to metal contamination. Soil samples from five metal workshops in Potiskum town, Yobe State-Nigeria were collected at the main workshops point, 30 m, 60 m and 90 m away from the workshop and a control sample at 250 m from the workshop point. Each sample was analyzed for ten heavy metals (Pb, Zn, Cr, Cd, Co, Mn, Ni, Fe, Se and Cu) using Atomic Absorption Spectrophotometer (AAS). The degree of contamination of heavy metals in the soil samples from the workshops ranged between 5.1 – 218.5, with Cu, Zn and Pb recording the highest degree of contamination values of 218.5, 20.7 and 13.4 respectively. While the lowest, 5.1 and 6.1 degrees of the contamination were recorded by Fe and Co respectively. Concentrations of the heavy metals follow order Cu>Zn>Pb>Mn>Cd>Ni>Se>Cr>Co>Fe. The soil samples analyzed are considered polluted with heavy metals with pollution load index far greater than one (PLI>>1) with pollution severity decreasing in the order GIM > GAS > GOA > NWC > GDH. Pearson correlation matrix between heavy metals levels in the soil samples with respect to distances from the workshops revealed gradual dispersion of the heavy metals to the nearest surroundings.