TITLE:
Application of Electrical Resistivity Imaging in Investigating Groundwater Pollution in Sapele Area, Nigeria
AUTHORS:
Okezie Uchegbulam, Elijah A. Ayolabi
KEYWORDS:
Electrical Resistivity, Imaging, Pollution, Traverse Lines
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.6 No.14,
October
31,
2014
ABSTRACT: Sixty-four
multi-electrode Lund imaging system coupled with ABEM SAS 4000 Terrameter was
used for the electrical imaging of the study area. Wenner and Gradient arrays
with 2 m minimum electrode spacing were employed which revealed resistivity
changes in the vertical and horizontal directions along the survey lines. Earth
imager software was employed forthe processing and the iteration of
the 2-D resistivity data. The subsurface is characterized with soil material
with resistivity ranging from 42 - 15,000 Ohm-m, reflective of varying degree
of conductivity associated with changing lithology and fluid type. Correlation
with borehole data shows that the first 10 m is composed of laterite. While
sand materials occupy 10 to about 60 m beneath the surface, with anomalously
high resistivity ≤15,000 Ohm-m in most parts. These
high resistivity formations can be attributed to the presence of hydrocarbon
within the subsurface, which is an indication that shallow aquifer in the study
area has been polluted. The water level in the study area is close to the
surface, between 4 - 5 m. As a result of the high resistivity formations in
most parts, deep wells of about 45 m are recommended after geophysical
investigations.