Assessment of Leachate Contaminationof Groundwater Using Geo-Electrical and Physicochemical Methods at Albishiri, Minna, Northcentral Nigeria.

Abstract

Assessment of leachate contamination of groundwater was carried out at Albishiri landfill, one of the old and major waste disposal sites in Minna. The geo-electrical method namely Vertical Electrical Sounding (VES) and Induced Polarisation (IP); and physicochemical analysis of sampled water were applied to assessing the leachate contamination of the subsurface resource. Two parallel profiles at the margins of the landfill consisting of 18 VES and IP stations were investigated. Interpretation of the data was done using the 1-D iterative program IPI2win. The results obtained show that the area is generally underlain by three geologic formations (lateritic top soil, weathered/fractured basement and fresh basement) corresponding to the geo-electric models. However, where the basement has experienced more weathering leading to fracturing of the basement rocks, four layer models were obtained. Leachate plume seepage and contamination is at varying moisture content and depth. Prominent areas with significant IP effect, permeability and overburden thickness of 15 m and above were located at the eastern region of the landfill. The rate of leachate contamination at the study area was found to be 0.7 m per year. Physicochemical analysis of the water sampled indicated elevations in chromium and iron with values of 0.06 mg/L and 0.31 mg/L. These were clearly above the recommended guideline for quality drinking water thus, may be detrimental to human health.