GEOPHYSICAL INVESTIGATION OF CONTAMINANT PLUME OF OFFA-GARAGE OPEN DUMPSITE, ILORIN SOUTH L.G.A., KWARA STATE, NIGERIA

Abstract

2-D Electrical Resistivity Profiling (2-D ERP) method was deployed to map the extent of leachate contamination in 
near-surface soil and rocks around Offa-Garage open dumpsite in Ilorin, Kwara State, North Central Nigeria. The 
ER profiles were carried out in the month of November (Dry season) and repeated in the month of September 
(Raining Season). Ilorin lies within the coordinates of 40 28.67’ E, 80 27.2’N; 40 35.76’ E, 80 27.2’N; 40 28.67’ E, 80 
35.2’N and 40 35.76’ E, 80 27.2’N; 40 35.76’E, 80 35.2’N. Electrical Resistivity Profiling was established using 
DDC-8 resistivity meter by adopting Werner alpha configuration with half – currents electrode spacing that ranged 
from 1 to 100 m. A contaminant leachate plume was delineated in 2-D resistivity sections as low resistivity zones in 
the range 0.644Ωm -3.15Ωm for the month of September identified as raining season period and 0.649Ωm -2.89 Ωm 
for the month of November as dry season period of the year under study. The spread of leachate was observed in the 
range of range of 22.0 -27.0 m laterally and 1.35 -7.88m vertically in the study location for the months Under study. 
The result showed that location have been contaminated due to the migration of leachate. This was evident from the 
Low Resistivity values of the ERT. The Conclusion from this study was that leachate is present in the area.