Application of Electrical Resistivity Tomography in Mapping Subsurface Hydrocarbon Contamination

Abstract

The subsurface soil around Baruwa community was reportedly contaminated by hydrocarbon not because the area falls within oil-producing community but it suffers from inceasant leakage from petroleum pipeline that supply petroleum products to hydrocarbon terminar located within the area. Thus, to ascretain the extent of contamination of the subsurface soil around the area, an integrated geophysical methods involving vertical electrical sounding (VES) and electrical resistivity tomography (ERT) supported with induced polarization (IP) and spontaneous potential (SP) methods were carried out. The hydrocarbon contaminated layers were marked out beneath each VES point by high resistivity ranging between 943Ωm and 4749Ωm at a depth of 1 to 35.44m below the surface. Similarly, ERT result shows that the subsurface soil around the investigated area has been contaminated at a shallow depth of about 2m downward with resistivity value above 1000Ωm. IP and SP data were Integrated to identify the sandy contaminated layers from clayey layer. IP value of 0 to 10mV/V and SP values of <+10mV were obtained over the sandy formation. The work shows that hydrocarbon leaking from the pipeline laid a few meters beneath the earth surface actually flow both upwardly (possibly due to seasonal variation in the water table which is usually close to the surface during rainy season) to the surface and downwardly at greater depth into the subsurface, through a porous medium -sandy layer. This may probably accounts for the reason while most of the handdug wells in the area are reportedly contaminated with hydrocarbon products.

Applying FDEM, ERT and GPR at a site with soil contamination: A case study

“…The applications of ERT have since extended to environmental pollution investigations. For example, ERT can survey pipeline or tank leak incidents, verify sewage leakage and define the scope and depth of landfills (Ayolabi et al, 2013;Batayneh, 2005;Dahlin et al, 2002;Godio and Naldi, 2003;Martı'nez-Paga'n et al, 2010). During or post-remediation work, ERT can assess or confirm remediation results or indicate locations where require further improvement (Goes and Meekes, 2004;Halihan, T. et al, 2005).…”

Rapid In-Field Approaches for Delineating VOC in Both Soil Vapour and Groundwater for Vapour Intrusion Assessment

“…In our prior study (Wang et al, 2021), an easy-to-install and retractable soil vapour sampling probe (SVSP) was introduced to rapidly sample soil vapour (Ayolabi et al, 2013). After being installed in a pre-drilled borehole and sealed with bentonite, it was found to work satisfactorily for soil vapour samples collecting from a range of soil depths.…”

“…Changes in soil lithology, saturation, and salinity, as well as groundwater and groundwater contamination, all contribute to geologic variations in ground resistivity values. Furthermore, ERT can be used to relate soil contaminant characteristics, such as hydrocarbon pollution (Arrubarrena Moreno and Arango-Galván, 2013;Ayolabi et al, 2013) and heavy metals (Bravo and Benavides-Erazo, 2020). In this study, ERT was used to identify and locate naturally developed groundwater channels that cross the source zone.…”

Application of cross-hole electrical resistivity tomography to groundwater contaminated remediation site

“…As ERT has the ability to produce high resolution images of formations at shallow depths, it is widely used in geology, archaeology, engineering, and environmental surveys (Bowling et al 2007;Soupios et al 2007a;Chang et al 2012;Lin et al 2013;Loke et al 2013;Tong et al 2013). Furthermore, ERT, undertaken in environmental contamination research such as investigations of landfills and groundwater contamination sites, can be used to clarify the scope and depth of landfills, investigate spills in contaminated areas, identify possible leakages, or assess the spatial distribution of contaminants (Atekwana et al 2000;Halihan et al 2005;Soupios et al 2007b;Yang et al 2008;Atekwana and Atekwana 2010;Martínez-Pagán et al 2010;Vaudelet et al 2011;Ayolabi et al 2013;Wang et al 2015). More specifically, cross-hole electrical resistivity tomography (CHERT) involves placing current and potential electrodes in boreholes.…”