Detecting Underground Storage Tanks and Contaminated Areas in Petrol Stations by using 2D ERT

It is worrying the pollution in soil and/or groundwater as a result of leaks of petroleum products in a lot of scenarios in all over the world. These scenarios are presented as potentially contaminated areas by the possible presence of organic pollutants in soil or even they could reach the groundwater bodies. Through this research it has been made an environmental diagnosis to identify possible leaks in underground storage tanks and plumes in the subsoil by applying a non destructive geophysical technique in petrol stations located in Murcia, Spain: Electrical Resistivity Tomography 2D as a tool to evaluate the state of the subsoil, locating underground facilities and to point out anomalous areas where a contamination by leakage may have taken place. Three ERT profiles were carried out in each petrol station and each season (wet and dry period). The results show different confined zones in the subsoil with electrical resistivity values up to 2000 Ω•m, very high values for a natural soil, where hydrocarbons content in soil samples is above 50 mg TPH/kg, requiring a further risk assessment. Moreover, ERT results indicate the underground storage tanks positions in the subsoil of petrol stations.