Paper Title
Rn-222 AND Ra-226 IN GROUNDWATERS FROM AQUIFER SYSTEMS OCCURRING AT SÃO PAULO STATE, BRAZIL

Abstract
This paper describes the characterization of the natural radioactivity due to dissolved radionuclides 222Rn and 226Ra ingroundwaters occurring in sedimentary (Bauru, Guarani, and Tubarão) and fractured rock (Serra Geral) aquifer systems in the Paraná sedimentary basin (PSB), Brazil.PSBpossesses a total surface area of about 1.6106 km2, comprising southern Brazil, eastern Paraguay, NW Uruguay, and northeastern extreme corner of Argentina.It is intercratonic, with a sedimentary sequence covering since the Silurian-Devonian up to the Cretaceous periods. The analyzed waters are extensively used for drinking purposes, among others, being important to monitor their quality in terms of radiological parameters as reported in this paper. Keywords - Dissolved Rn-222 and Ra-226, Groundwaters, Paraná Sedimentary Basin, Brazilian State of São Paulo