Estimation of Soil Hazard Quotient of Some Identified Heavy Metals from an Abandoned Municipal Waste Disposal Site in Aba, Nigeria.

The soils of an abandoned waste disposal site reclaimed for commercial activities have been investigated for heavy metal concentration using an Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer. 20 samples were collected with a coring material 5 cm below the soil from five representative points (each of the points in regular grids of 50 m by 50m). The results obtained showed that the mean heavy metal concentrations were 5327.5 mg/kg, 2273.4 mg/kg, 797.1 mg/kg, 11104.7 mg/kg, 862.6 mg/kg for chromium (Cr), cobalt (Co), copper (Cu), zinc (Zn) and Lead (Pb) respectively. These results were found to be higher than the international permissible limits and the world average concentration of heavy metals in soil. All the identified heavy metals had their Hazard Quotient far greater than unity implying that the site has been heavily polluted by disposed wastes and may pose significant health risk to occupants of the site. Certain remediation processes were suggested to make the place less toxic and more accommodating for humans. Keywords: Soil, Heavy Metal, Hazard Quotient, Wast