METHODOLOGY FOR STUDIES OF GROUNDWATER QUALITY AND ITS APPLICATION FOR HYDROGEOCHEMICAL CHARACTERIZATION OF THE GUARANI AQUIFER. The Guarani Aquifer is one of the largest reservoirs of groundwater in the world and represents a strategic reserve for the four countries where it occurs in South America – Argentina, Brazil, Paraguay and Uruguay. The municipality of Ribeirão Preto, located in the northeastern region of the state of São Paulo, with a population of over 600,000 inhabitants, is supplied entirely by waters of the aquifer. In this city and region it occurs intensive use of groundwater; a large number of operating wells already show problems of interference among each other. At the same time, one can notice the increased risk of contamination of groundwater by increasing the fonts installed on places where the aquifer is at the surface (primarily related to pesticide use for agriculture), which are highly vulnerable. This paper presents a methodology for investigation of data quality groundwater chemistry and its application to the hydrogeochemical characterization of the Guarani Aquifer, within the territory of Ribeirão Preto and region.
