Levels of Heavy Metals in and Around Scrap Car Dumpsite at Uwelu, Nigeria

Abstract

Soil contaminated with heavy metals can result to very serious environmental hazard. As a result of this problem, this research was carried out to investigate the concentration of heavy metals (Fe, Zn, Pb, Cu and Cr) in and around Uwelu scrap car dumpsite in Benin City, southern Nigeria. In carrying out this research, a total of 36 soil samples were taken for laboratory analysis. The soil samples were collected at various depths at the dumpsite, and at various horizontal distances from the dumpsite including human settlements close to the dumpsite, in order to ascertain the levels of toxic heavy metal concentration on human living habitat around the dumpsite. The heavy metals in the waste soils samples were sequentially extracted and measured using atomic absorption spectrometry (AAS). The results show that Fe had the highest concentration of 515mg/kg, followed by Zn, 236.8mg/kg, Cu, 78.61mg/kg and Cr, 0.94mg/kg at the dumpsite surface, where all the metals recorded their highest concentration. The level of Fe and Pb were above the Federal Environmental Protection Agency (FEPA) minimum acceptable limit. Besides, the concentrations of these heavy metals decreased with increased vertical depth at the dumpsite and with increased horizontal distance from the dumpsite. Similar trends were observed for the various soil pH.