Two-dimensional electrical imaging for detection of hydrocarbon contaminants
Authors:
A. Godio and M. Naldi
Journal name: Near Surface Geophysics
Issue: Vol 1, No 3, August 2003 pp. 131 - 137
DOI: 10.3997/1873-0604.2003003
Language: English
Info: Article, PDF ( 1.84Mb )
Price: € 30
Summary:
The effects of a long-term diesel oil pollution due to leakage from buried tanks have been
investigated using electrical resistivity tomography. The reliability of 2D electrical resistivity
imaging of the subsoil was assessed using a numerical modelling approach that simulated the
different behaviour of the contaminated zone. The effects of inversion parameters, such as
the damping factor and smoothing matrix, have been studied in order to evaluate the optimal
parameters to process real data.
The results of the field test indicated that highly conductive anomalies can be related to
the biological degradation of hydrocarbons: geochemical analysis performed on several
groundwater samples confirmed the presence of biodegradation activity. Chemical analysis
pointed out an anomalous concentration of iron and manganese cations dissolved in the
groundwater. Very low values of resistivity can be associated with a marked modification of
the cation exchange capacity of the soil mixture due to degradation of these hydrocarbons.
Chemical and physical interactions due to hydrocarbon pollution affect the electrical properties
of soils and groundwater.
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