GROUNDWATER VULNERABILITY TO CONTAMINATION IN URBAN AREA – GUARATIBA AQUIFER, RJ

Abstract

The DRASTIC method a widely applied method for assessing the intrinsic vulnerability of an aquifer based on the parameters: depth, recharge, aquifer type, topography, impact on vadose zone, soil and hydraulic conductivity. However, studies indicate that these parameters alone are insufficient to characterize an aquifer inserted in an urban area. Thus, DRASTICA method was developed with the addition of the anthropogenic impact parameter. This research work presents the study of vulnerability of the Guaratiba aquifer, Rio de Janeiro city, based on the DRASTIC method and its adaptation DRASTICA. The DRASTIC vulnerability map showed three classes, with a predominance of the lower and middle classes with 0.8% of study area high potential vulnerabilities. The DRASTICA vulnerability map shows the influence of anthropic activities, since the high vulnerability class with 5% of the research area. Thus, in the DRASTICA method, it is observed that the presence of high vulnerability in the highest concentrations of nitrate ions and, moreover, lowest nitrate concentration are not present in this respective class. Therefore, it is concluded that for studies of aquifer vulnerability in urban areas, the DRASTICA method is indicated.