The distribution of chemical elements and minerals in the sub-surface is the result of several geological processes that can cause a dispersion or accumulation of elements in certain areas. Anthropogenic activities such as mining and industrial processes that manage some chemical elements can create abnormal geochemical accumulations. Those unnatural anomalies can cause potential damage in the environment such as soil and water contamination.
In the environmental assessment of contaminated areas , conducting geophysical surveys has the basic objective of identifying the presence of groundwater contamination and the definition of the geological and hydrogeological features of the investigated sites .The characteristics of the geological environment , and the nature of the contamination, can determine the behavior of contaminants in the subsurface.
The application of two or more distinct geophysical methods increases the accuracy of interpretations, and the nature of the contaminant and the local geology are decisive in the selection of geophysical techniques to be used factors .Significant deviations from the normal pattern of geophysical measurements may point to the presence of contaminants in the subsurface . The interpretation of the anomalies is critical as it can indicate the intensity of this contamination, thus providing important activities for diagnostic, monitoring the spread of contaminants and monitoring the recovery of a contaminated area data.
Methods such as the Electrical Resistivity Tomography (ERT), IP or magnetic mapping can identify concentrations of contaminated soil, estimate its subsurface distribution and help creating pollution maps.