Assessment of intrinsic vulnerability to the contamination of karst aquifer using the COP method in the Carste Lagoa Santa Environmental Protection Unit, Brazil

This study addresses the intrinsic groundwater vulnerability by using the COP method index and GIS technology on the karst-fissured aquifer of the Carste Lagoa Santa Protection Unit, located in the state of Minas Gerais, Brazil. This area has a great importance due to its rich paleontology, archeology and speleology. The region is groundwater dependent, and it has been suffering pressure by economic development. Therefore, it is important to identify vulnerable areas in which infiltration of contaminants is likely to happen. The main goal of this study was to create an intrinsic groundwater contamination vulnerability map (scale 1:50.000), which will be used to assist the implantation of groundwater monitoring net project in the area. The index vulnerability was evaluated by analyzing COP model parameters through geoprocessing techniques. However, in order to adapt the method to the studied area conditions, changes in frame and values of input parameter weights (lithology and slope/vegetation) were necessary. The outcomes showed five categories of groundwater contamination vulnerable zones: high to the highest vulnerability level (10.95%), moderated (58.77%) and low to the lowest vulnerability (30.28%). Despite the low percentage of high to the highest vulnerably level area, they must be considered by environmental managers due to strong relationship between superficial and groundwater in the area.