Determination of Concentrations of Heavy Metals in Municipal Dumpsite Soil and Plants at Oke-ogi, Iree, Nigeria

Abstract

The study examined the concentration of heavy metals [Cd, Co. Cu, Pb, Ni, Mn, Pb and Zn) in dumpsite soil and waterleaf [Talinum triangulare) growing wildly on Oke-ogi dumpsite, Osun state, Nigeria. Soil samples from different layers [0-15cm, 15-30 cm and 30-45 cm) were collected in triplicate and analysed using Atomic Absorption Spectrophotometer. Pb had the highest mean ± SD 91.67±13.80 mgkg-1followed by Zn, which is 20.85±4.80 mgkg-1. Mean concentration of Pb and Zn in the soil of the control site is significantly lower than [Pb, 10.67±2.08 mgkg-1) and [Zn, 2.58±0.38 mgkg-1) respectively. Concentration of Pb in both the dumpsite soil and plant in excess of allowable limit. Concentration of Co in the dumpsite soil [0.02 – 0.72 mgkg-1). Fe is the most abundant element in the vegetable with a mean value of 186 mgkg-1 followed by Zn [8.63 mgkg-1). Heavy metal concentrations followed the order of Pb>Zn>Mn>Cu>Cd>Co in the both the control and dumpsite soils most of which falls below the critical permissible concentration level, their persistence in these soils of the dumpsite may lead to increase uptake by plants. Transfer factor for Cd and Mn were 1, while others values are below 1. Elevated heavy metal concentrations at dumpsite need to be properly addressed given the fact, that inorganic waste are being dumped by the people. This can be done if the sitting of dumpsite is regulated, minimizing waste and remediation techniques, such as bioremediation that have shown potential for their ability to degrade and detoxify certain contaminants.