Hydrocarbon contaminated soil: geophysical-chemical methods for designing remediation strategies

Abstract

Rapid and correct characterizations of contaminant plumes are necessary to plan efficient and economically viable remediations of affected zones. In this context, we have carried out a joint implementation of two geophysical non-invasive methods and chemical monitoring from wells to characterize an area affected by a hydrocarbon spill caused by a traffic accident involving a transport truck and its trailer. The studied area is situated in Alejo Ledesma, Argentina and has an area of 4350 m2. The geophysical prospecting was carried out through the resistivity and the electromagnetic induction methods. The first method provided precise vertical resistivity sections, which were acquired at representative contaminated/uncontaminated sectors, whereas the second allowed a quick prospecting of the entire area. The chemical procedure consisted of samples obtained from a small number of monitoring wells, which were located at selected positions. We correlated the geophysical interpretations with the chemical data to delimit the zone affected by the spill. The detection and characterization of the contaminated plume by the geophysical methods showed positive results even though a liquid phase was not present at the site. A remediation methodology could be determined from these results. The efficiency of the applied methodology (stabilization/solidification) was also confirmed through these methods.