Geo electrical Signature of Long Term Hydrocarbon Contamination in Serbia

The detection of petroleum hydrocarbon contaminants such as light non-aqueous phase liquid (LNAPL) in the subsurface using geophysical methods, particularly electrical resistivity methods has been the subject of considerable interest in recent years. Their detection is based principally upon the electrical soil properties and processes related to biodegradation of the hydrocarbons. Direct current resistivity data were collected at the location of RNS (Oil Refinery Novi Sad) and "Obrenovac centar" fuel station site, Serbia. The objective of this study was to evaluate the possibilities of resistivity imaging techniques in detecting and locating anomalies of hydrocarbon contamination. Resistivity measurements were carried out utilizing the Wenner array configurations. In order to achieve good vertical and lateral resistivity distributions for the investigated site electrode spacing was 1 m. The interpretations obtained from 2D-modelling of the field data show a highly conductive region in areas with LNAPL contamination. This explanation was supported by the presence of free hydrocarbon phase floated on the surface of water filling the drilled boreholes and geochemical analysis of core sample collected on these two investigation site.