Vertical electrical soundings in the mapping of vulnerability to contamination of the Adamantina aquifer in Urânia, São Paulo, Brazil

Abstract

The municipality of Urânia has faced problems with contamination of the Adamantina aquifer since the 1970s, as well as many urban areas in São Paulo State. One of the fundamental tools for territorial planning is the mapping of vulnerability to aquifer contamination. One of the limitations of such technique is the difficult access to the aquifer for defining aquifer levels and the lithological characteristics of the unsaturated zone. Thus, the present article identifies the aquifer recharge areas that are most susceptible to anthropogenic degradation, using a geophysical technique of vertical electrical sounding (VES). The results were obtained through VES and shallow monitoring wells. The vulnerability index was defined by the parameter of the longitudinal conductance of Dar Zarrouk, combined with the characteristics of the aquifer. The vulnerability map indicated the southeast study area as the most prone to contamination due to the permeable geological material and the low thickness of the unsaturated zone.