Application of Pb, Sr, H and o isotopes as tools for studies of groundwater recharge and contamination in the West zone of São Paulo City, upper Tiete Watershed

Abstract

The groundwater management in Metropolitan region of Sao Paulo and its sustainable use depends on two main factors, the study of quantity and quality, ie the recharge and water contamination. Understanding how the recharge occurs and whether the contamination found is of natural or anthropogenic origin are essential for managing this resource. It's part of this task understanding how occurs the interaction between the various frameworks such as surface water, geological material, groundwater and anthropogenic materials. Preliminary data (Martins, 2008) have shown that the Sr, Pb, H and O isotopes are good indicators of the interaction processes between the earth espheres, also to identify sources of contamination and for evaluation of aquifer recharge. To extend the data obtained previously and promote the results we intend to study three distinct cases of contamination with different hydrogeological conditions, to evaluate the application of different isotopic systems in the study of recharge and identifying sources of contamination. The first involves the contamination of fluoride and barium anomalies in the shallow aquifer at Cidade Universitária district; the second deals with fluoride contamination in deep crystalline aquifer at Barra Funda district; and the third is about barium contamination both in deep sedimentary aquifer at the region of Salto de Pirapora, as in the crystalline aquifer at Barueri. In addition to groundwater samples it is going to be collected surface water samples and rainfall, as well as domestic sewage and wastewater treatment samples, that may be contributing to the studied aquifers recharge. The comparison with more scientifically accepted isotopes and other cases studies will support the results obtained. (AU)