PRELIMINARY ER AND EM GEOPHYSICAL INVESTIGATIONS OF A WASTE LANDFILL NEAR THE CITY OF FORTALEZA - NE OF BRAZIL

We have performed a geophysical investigation on a site used for disposal waste of several types and sources. The site is located near the city of Fortaleza, state of Ceara, in the NE part of Brazil. The area is characterized by a flat surface without significant relief, unless the elevations of compacted landfill. The geology is composed by recent sediments of Barreiras Formation (TQ), mainly clays, sands and residual soils. The objective of the geophysical surface investigation was to use a multi-electrode dipole-dipole array with an AGI instrument and an electromagnetic 3 frequency method with a Geonics instrument to delineate possible buried zones through 2D interpreted sections. The information collected in this investigation may be useful to delineate possible contaminated plumes and its influences in the shallow aquifer system. This research began in December 2009 and it will still continue along the year of 2010 with other complementary geophysical and geochemical studies. The results shown that the geophysical techniques are able to map contaminated areas and that the ER method has a higher resolution. Direct investigations prove their efficiency.