DETERMINATION OF SOIL CORROSIVITY VARIATION AND AQUIFER PROTECTIVE CAPACITY LEVEL USING RESISTIVITY METHOD IN EJIGBO, OSUN STATE, NIGERIA

Electrical resistivity method (ERM) with the Schlumberger arrangement was conducted at Ejigbo, Ejigbo Local Government, Osun State, Nigeria in order to determine the soil corrosivity variation and aquifer protective capacity level. 13 Vertical Electrical Soundings (VES) were carried out in the study area and data interpretation was done using partial curve matching approach, iterative resistivity sounding interpretation software (WinRESIST Version 1.0) and surfer8 software. The result of the geophysical investigation revealed two (2) to five (5) subsurface geo-electrical layers. The topsoil resistivity values obtained from the interpretations results were used to evaluate the corrosivity of the subsoils. VES’s 1, 2, 4, 5, 6, 9 and 12 have relatively high topsoil resistivity values which is “practically noncorrosive”, while VES’s 7, 8, 10, 11 and 13 have slightly corrosive and VES 3 has moderate corrosivity. Four distinct aquifer protective capacity zones were defined based on the longitudinal conductance values. They are poor (VES’s 5, 9, and 12), weak (VES’s 3 and 6), moderate (VES 7) and good (VES’s 1, 2, 4, 8, 10, 11 and 13) aquifer protective capacity zones. ERM has proved to be very dependable for the determination of Soil Corrosivity Variation and Aquifer Protective Capacity Level of the study area.