2D electrical tomography and gravimetry for the detection of a site contaminated by oil derivates in an area of environmental liability

ABSTRACT

The following geophysical essays were performed: DC resistivity survey (dipole-dipole array) with AB=MN=4 m, totaling 1.024 m of profiles, and a magnetometric survey, totaling 273 stations split every 4 m. The maximum, minimum, and average values, and the standard deviation of the actual resistivity in ohm.m were respectively: 35, 2,276, 432, and 344. Regarding the Bouguer gravity anomalies, it was observed that the eastern portion is characterized by signals with larger amplitudes, in contrast to the western segment, where these are intermediate to low, especially minimum values between stations 0-44 meters, from lines L4, L5 and L6. The presence of hydrocarbons was detected at a depth of 3 m in lines L8 and L9. Laboratory analysis of soil and water samples showed values of PHAs that exceed the parameters established by the CONAMA resolution nº 357/2005.

Keywords:
environmental liability; petroleum; electrical tomography; gravimetry