Estudo geofísico do Aterro Sanitário de Monte Carmelo (MG)

Abstract

The present study addressesthe application of the geophysical method of Electroresistivity (ER) for subsurface survey at the Municipal Landfill of Monte Carmelo (MG). The deposition of solid waste can lead to the contamination of soils and of both surface and groundwater by chemical agents, such as leachate, if such activity is carried out inadequately. Historically, the ER method has been proven to be a significant tool for evaluating and monitoring environmental conditions in open dumps and sanitary landfills. As a relatively simple and costeffective method of investigation, ER is useful for identifying higher-conductivity anomalies which may be related to higher concentrations of leachate within the soil, thus allowing the identification of potential contamination plumes in the subsurface. In this context, the objective of this study is to locate probable contamination plumes and, if they are present, to evaluate their extension within the study area. Three 2D surveys were carried out, and the data were analysed using Res2DInv. Many low-resistivity anomalies were observed, suggesting the existence of contamination plumes, one of which is located next to the leachate lagoon. However, the results are subject to high contact resistance interference for the electric current flow from the instrument to the soil, given that at some parts the shallower layer is composed by a layer of broken tiles, thus significantly increasing the contact resistance. Deeper highresistivity anomalies were interpreted as a response to the presence of granitic boulders in the subsurface, considering the predominance of this lithology throughout the site. The data and analyses presented are expected to serve as a pilot study for future monitoring efforts in the contaminated area, thus constituting an auxiliary tool for the management of the landfill by the responsible authorities.