Hydrochemical study of the tubarão aquifer system (TAS) in the municipality of Americana, SP

Abstract

The Municipality of Americana (SP), located in a densely populated area of the Campinas Metropolitan Region, is characterized by low surface water availability and a large number of deep wells that exploit the Tubarão Aquifer System (TAS). In the face of the increasing demand for exploitation of water resources, hydrochemical studies are essential for planning and management of these resources. Using Piper -Stiff diagrams and statistical analysis (cluster analysis) of the chemical components of the water samples collected from deep wells for public supply, three hydrochemical types were identified: Ca-Na-HCO3, Na-HCO3 and Na-Cl. The first type presents basic pH, weak salinity and electrical conductivity between 106.9 and 213 µS/cm. The sodium bicarbonate type shows pH between 6.74 and 7.99 (average 7.52) and conductivity values from 239 to 19.18 µS/cm, while the chlorinated water with sodium type has a pH between 5.08 and 7.13 and electrical conductivity from 242 to 67.2 µS/cm. The samples registered high concentrations of nitrate with chloride, which indicates the possibility of contamination of the aquifer by human action.