Ferramentas Hidrogeoquímicas e Isotópicas (δ18O e δ2H) Aplicadas no Entendimento dos Processos de Salinização da Água Subterrânea em Aquíferos Carbonáticos Proterozoicos: Evidencia do Semiárido do Nordeste Brasileiro

Abstract

Groundwater in arid and semi-arid regions is frequently the only available source of water for the population. Quality decline or deterioration is considered a crucial problem for the management of groundwater resources. In this study, a hydrogeological investigation was carried out using geochemical and isotopic data in a karst aquifer, installed in the Proterozoic carbonate rocks of the Salitre Formation: southern portion of the Irece Basin, Chapada Diamantina, Bahia, Brazil. The aim was to understand the hydrogeochemical and physical processes that contribute to the salinization of groundwater. This understanding is essential for the sustainable exploitation of water resources. The main results indicated that the processes of evaporation and leaching were not very efficient in the reconcentration of mineral salts in the vadose zone of the aquifer. Hydrogeochemical and isotopic modeling showed that the salinity of the groundwater is subjected to geological processes, resulting from rock-water interaction. The integrated use of geochemistry and stable isotopes (δ18O and δ2H) in karst aquifers is an important instrument in the modeling and understanding of groundwater salinization processes and an effective tool in the evaluation and management of water resources.