Electrical characterization of a contaminant plume due to a hydrocarbon spill

OSELLA, A.,; DE LA VEGA, MATIAS; LASCANO, EUGENIA

JOURNAL OF ENVIRONMENTAL AND ENGINEERING GEOPHYSICS

ENVIRONMENTAL ENGINEERING GEOPHYSICAL SOC

Año: 2002 vol. 7 p. 78 - 87

1083-1363

The objective of the research contained in this paper was the characterization of a contaminant plume and the description of the surrounding area, in order to give information for future remediation. The origin of the plume was a hydrocarbon spill produced by fissures in a purge chamber belonging to a gas transmission system. Data from control wells indicated that the soil was composed mainly of clays. The most important result was that, close to the chamber, a 1.5 m-thick layer of gasoline was detected at 7 m depth, floating over the water table. This is a case in which a resistive contaminant like hydrocarbon is located in a conductive medium, in these circumstances a geoelectrical prospection is particularly good for characterizing the zone. The extent of the area under study was 100x140 m2 , approximately, and the thicknesses involved were more than 20 m of, in many cases, very conductive materials. Thus, a field design was required that would cover the zone with deep penetration and at the same time optimize lateral resolution. By combining Wenner and dipole-dipole configurations, the electrical imaging of the contaminated zone and the description of the surrounding soil were achieved.