Assessment of some physicochemical properties and levels of Pb, Cu and Zn in soils of selected dumpsites in Kano Metropolis, North-West, Nigeria

Abstract

Some physicochemical properties (pH, electrical conductivity (EC), cation exchange capacity (CEC), organic carbon (OC) and particle size analysis) and levels of Pb, Cu and Zn in soil samples collected from particular dumpsites within Kano Metropolis were analyzed with the view to evaluating the impact of solid wastes on the soils. Heavy metal contents were   determined using Atomic Absorption Spectrophotometer while conventional analytical methods were employed for the analysis of the physicochemical properties. The results of the physicochemical properties revealed values ranging from 7.84 - 8.26 (pH), 171.3 - 286.1µScm^-1(EC), 8.22 -  14.96Cmol/kg (CEC) and 1.35 - 1.86% (OC). The textural class of the soils was mainly sandy loam. The mean concentrations of the metals analyzed from the dumpsite soil samples were in the range of 12.61 - 84.3mgkg^-1 for Pb, 20.64 - 35.39mgkg^-1 for Cu and 232.3 - 610.4mgkg^-1 for Zn, while the mean concentrations of the metals analyzed from the control site soil samples were in the range of 0 - 11.1 mgkg^-1 for Pb, 5.7 - 11.0 mgkg^-1 for Cu and 69.03 - 120.8 mgkg^-1 for Zn. Metal contaminations of the soil dumpsites were in the order of Zn > Pb > Cu. Correlation analysis was used to examine the dependency of heavy metals upon themselves, Pb correlates with Zn in all dumpsites. The results of the analysis of the  samples evidently indicate higher contamination of heavy metals, as well as higher values for some physicochemical properties at dumpsites when compared with the control sites; this may pose a serious risk to the  environment in which the dumpsites are located.

Keywords: Physiochemical properties, heavy metals, dumpsite, soil, contamination.