Geoelectrical Assessment of the Extent of Groundwater Contamination Around Waste Disposal Site of Dan’agundi, Kano Municipal Local Government, Kano State

Abstract

A geophysical investigation was carried out at an unmanaged open solid waste site 
located in the Dan'agundi area of Kano, aimed at identifying potential zones where 
Leachate may be seeping into the groundwater. The study involved conducting 
Vertical Electrical Sounding (VES) as well as measuring the electric field component 
of the natural electromagnetic field at five locations both within and outside the 
dumpsite. The VES data analysis revealed three distinct geo-electric layers: the 
topsoil, the weathered basement, and the fractured/fresh basement. The topsoil 
exhibited a thickness ranging from 1.15 m to 2 m, with apparent resistivity values 
(ρ_a) varying between 22.4 °C and 51.6 °C. The weathered basement layer 
showed a thickness between 1.13 m and 11.7 m, with ρ_a values ranging from 12.6 
m to 3.31 m. For the fractured/fresh basement, the apparent resistivity values 
ranged from 37.7 °C to 188.5 °C. The analysis of the electric field data indicated 
that leachate contaminants had penetrated the subsurface to depths ranging from 
approximately 2.5 to 40 m. This suggests that leachates are concentrated around 
the landfill, posing a significant risk to groundwater quality in the surrounding area. 
To mitigate the potential contamination of groundwater by landfill leachate, it is 
recommended that boreholes for water extraction be drilled to depths beyond 40 m 
to access cleaner, less permeable zones. Additionally, it is advisable to situate any 
new wells or boreholes at least 100 meters away from the dumpsite to further 
reduce the risk of leachate infiltration. These preventive measures are critical for 
ensuring the safety of groundwater sources in the region