Surface Soil Pollution By Heavy Metals A Case Study Of Two Refuse Dumpsites In Akure Metropolis

ABSTRACT Heavy metals can be harmful to the biota and human beings when present above certain tolerable levels in the ecosystem. This lead to the study of the accumulation contamination and pollution of these metals in soils of two refuse dumpsites within and outskirts of Akure Township capital city of Ondo State Nigeria. The dumpsites are where wastes such as industrial wastes automobile wastes municipal wastes agricultural wastes etc were dumped. At each site soil samples were collected randomly from nine different points of about 1m part at depth of about 0-30cm and analyzed for heavy metals and pH. The metals analyzed include Zn Fe Co Cu Ni As Ba Pb Cr and Cd using Atomic Absorption Spectrophotometer AAS with HFAqua regia wet digestion method. The pH of the soils ranged between 7.49 and 8.66. The results revealed heavy metal presence and implicated wastes as the major sources of the heavy metals in the soils of the dumpsites. All the metals were detected in all the soil samples except Arsenic that was not detected in three points at site A. Fe had the highest concentrations while Ni had the least concentration in both sites. The trend in concentration was Fe Zn Pb Cu Cd Co Cr AsBaNi in site A While the trend in concentration was Fe Cr Zn Cu PbCd Co As Ba Ni in site B. The mean metal concentrations were compared with Department of Petroleum Resources DPR Standard values for soils in Nigeria all the metals except Cr and Cu are below the DPR target values while Cd and Arsenic are above the DPR intervention values for the two sites and this calls for immediate remediation.