Geophysical Surveying To Investigate Groundwater Contamination By A Cemetery

Electrical resistivity, electromagnetic, self potential methods and ground-penetrating radar were used to study the subsurface of a cemetery in Southeastern Brazil and to investigate the groundwater contamination by the leachate from the corpse decomposition. The cemetery sits on the top of a hill formed by heterogeneous sedimentary deposits underlain by crystalline rocks. Vertical electrical sounding suggests the presence of lenses of low-permeability materials forming perched aquifers in the study area. Some of the perched aquifers were confirmed by boreholes. Self-potential data were used to check the groundwater flow. The responses of the electromagnetic fields showed anomalous results of apparent conductivities in local areas corresponding to burial places. Water samples obtained by observation wells have shown electrical conductivity values seven times greater than background data. Analysis of the samples detected the presence of pathogenic bacteria. Ground-penetrating radar profiles also suggested the subsurface contamination.