Conjunction of Geophysics and Hydrodynamic Modelling in Detection and Delineation of Contaminated Plumes

Oil contamination of groundwater is a very complex environmental problem. Efficient and economical assessment of the extent and nature of underground plumes is a very important aspect for environmental research. In this research we applied the Resistivity and SP methods to identify the boundaries of a LNAPL plume by detecting underground microbial activity at a predicted lateral plume boundary according to the results of a hydrodynamic simulation of the plume. The comparison between Resistivity and SP surveys in the site show that the presence of microbial activity at the core of the plume, identified by the measured SP values, coincides with low resistivity anomalies at the same zone in the Resistivity profiles and that the low resistivity location in turn coincides with the actual location of the core of the LNAPL plume. Therefore, it could be suggested that the combination of different techniques and methods, such as combination of hydrodynamic simulation, application of geophysical methods like resistivity and SP could help us to make better assessments on such important issues as the location and extent of the core of LNAPL plumes, its longitudinal and transverse boundaries and existence and extent of aerobic and anaerobic microbial degradation processes in underground pollution.