Design/Modification of a Virtual Instrument System for Electrical Resistivity Imaging in Environmental Pollution Studies: A Case Study of Sapele Local Government Area of Delta State, Nigeria

Abstract

This study was carried out at Elume Grammar School in Elume, Sapele LGA of Delta State, Nigeria with the sole aim of determining hydrocarbon contamination occasioned by petroleum pipeline vandalization near the study area. The National Instrument (NI) USB – 6255 data acquisition device was used for the electrical resistivity imaging (ERI) of the study area. The Wenner – Schlumberger array with  minimum electrode spacing was employed. Res2Dinv software was used for the processing and iteration of the  resistivity data acquired. The results of the geoelectric investigation revealed five geoelectric layers namely, the lateritic topsoil, sandy clay soil, fine coarse sand, medium coarse sand and coarse sand. The generated profiles of the acquired data helped map hydrocarbon contamination which was delineated as an area of anomalously high interpreted resistivities. This high resistivity can be attributed to the presence of hydrocarbon within the subsurface which is an indication that shallow aquifer in the study area may have been polluted. It is therefore recommended that chemical analysis of borehole water and soil samples from the survey environment should be carried out to ascertain the nature of the pollutant and the level of contamination if any.

Keywords

Electrical Resistivity Imaging (ERI), Virtual Instrumentation (VI), Hydrocarbon contamination