Geophysical Investigation around an Active Landfill Site in Ilokun, Ado-Ekiti, Southwestern Nigeria

Integrated surface geophysical surveys were carried out in the vicinity of an active waste dumpsite in Ilokun Ado-Ekiti. This was with a view to generating a subsurface model and hence determine its suitability, or otherwise, for landfill. It was also meant to determine its impact, if any, on the groundwater.

Seismic refraction survey was executed along three (3) traverses while six (6) vertical electrical soundings were done with a maximum current electrode spread of 100 meters.

Both geophysical techniques revealed overburden thickness of over 10m, the bulk of which is aquiferous. The clayey nature of the unsaturated zone indicates presence of seal that can prevent pollution of groundwater by leachate from the waste. Besides, there is no evidence of fractures below weathered zone.

Increase in resistivity of the water bearing zone with distance from dumpsite is indicative of pollution by the waste.