Investigação de plumas de contaminação e diagnóstico em subsuperfície através de métodos geoelétrico - Cemitério Municipal de Monte Carmelo, Minas Gerais

Abstract

Necroleachate is a viscous liquid generated from the decomposition of corpses, within the first year after death. This material is rich in mineral salts, degradable organic and inorganic substances, as well as potentially toxic pathogenic microorganisms that can cause risks to human health when consumed. Knowledge about the environmental impacts generated by necroleachate is relatively recent and has cemeteries as its main proliferator. The city of Monte Carmelo has an ancient historical-cultural history, with the municipal cemetery active since 1935, which means that many burials were carried out without due environmental planning, allowing the eventual formation of contamination plumes. The susceptibility of necroleachate to reach the water table, however, depends on the permeability of the soil/rock, the topography of the site and the depth of the water table. When this material is present in the geological environment, it can be diagnosed using geoelectric methods due to its low resistivity in relation to soils and rocks. This course completion work consists of the geophysical investigation of the subsurface to eventually recognize contamination plumes in anomalous electroresistivity responses in the Municipal Cemetery of Monte Carmelo, Minas Gerais, in addition to evaluating the groundwater vulnerability index to contaminants through the parameters of Dar Zarrouk longitudinal conductance. The data was acquired through Vertical Electrical Soundings (SEV’s) and Electrical Paths (CE). The low resistivity anomalies in contrast to the more resistive materials in the electrical paths were interpreted as possible zones of contamination by necroleachate. From the depth of the water table, thickness and resistivity of the unsaturated zone acquired in vertical electrical surveys, it was identified through Dar Zarrouk's longitudinal conductance calculation that the geological environment presents characteristics of high hydraulic conductivity and mobility of the possible contaminant. These data reinforce the need for soil sampling to analyze the amount of ions and bacteria to confirm the presence of the contaminant.