Assessment of some heavy metals in the surrounding soils of an automobile battery factory in Ibadan, Nigeria

Abstract

The levels of heavy metals (Pd, Zn, Cr, Cd, Fe and Cu in mg/kg) in soils were assessed with respect to distance in different directions around an abandoned battery company in Ibadan, Western Nigeria by using flame atomic absorption spectrophotometry method. The results generally show a decrease of lead (Pb) concentrations with increase in distance away from the company in all the four different directions (Northwest, Northeast, Southwest and Southeast). The other heavy metals assessed do not show any clear trend with distance away from the factory. The mean concentrations of Pb, Zn, Cr, Cd, Fe and Cu were 59.13±48.9 (range 5.00 - 182.00 mg/kg), 2.68±1.1 (range 0.4 - 5.2 mg/kg), 1.62±2.4 (range ND - 8.7 mg/kg), 0.08±0.09 (range ND - 0.24 mg/kg), 49.44±16.5 (range 12.5 - 70 mg/kg) and 4.94±2.6 mg/kg (range 0.5 - 10.5 mg/kg), respectively. The mean concentration of Pb was far above (four times higher than) the normal crustal average for soils while the other heavy metals were below the normal background level. The concentration of Pb is also the highest at the distance closest to the factory which indicate that Pb is the major heavy metal impacted on soils by the company which elevate the normal background level and thereby contaminate the soils and make it unfit for agricultural purposes as plant take up the leached metals and ultimately find its way into animals and human body through the food chain.

Keywords: Food chain, Battery Company, lead pollutant, assessment, agricultural purposes, anthropogenic sources