Assessment of Some Physiochemical Impacts of Municipal Solid Waste (MSW) on Soils: A Case Study of Landfill Areas of Lagos, Nigeria

Soil samples from all the active landfills in Lagos were analyzed for some physiochemical parameters in order to determine their suitability for use as compost. Of the assessed depth of 100 cm; from the surface to a depth of 20 cm, the concentrations of metals in the soil samples were in the order: Olusosun > Ewu-Elepe > Soluos 3 > Epe > Oshodi > Badagry. Concentrations of most of the analytes decreased with depth. Pb and Cr had the highest values of 95.3 mg/kg and 60.48 mg/kg respectively. Furthermore, the concentrations of the metals were higher than most of the anions. The cations were strongly and positively correlated with depth in most of the landfill soils such that Ni > Cd > Cr > Fe > K > Pb >Hg > As >Zn >K/ Mn. These imply significant attenuation with depth of the metallic imbuement possibly due to adsorption and/or precipitation. The alternative hypothesis was accepted for pH, EC, Fe, Pb, Cr at 99% confidence limit, and for Ni, Cd, As at 95% confidence limit. The elevated levels of cadmium and arsenic in the topsoils do not support their use as compost for food cultivation.