Study of radon exposure, chemical and radiological characterization of spring mineral waters from Águas de Lindóia and Poços de Caldas, Brazil

Abstract

Hydrothermal resources are used for health prevention and treatment worldwide based on drinking, bathing, and immersing in thermal mineral waters. In some places, 222Rn inhalation is also present. In Brazil, several locations apply thermal and hydrotherapies integrated into the Unified Health System as in Águas de Lindóia and Thermas Antonio Carlos in Poços de Caldas Town. The effective dose due to 222Rn inhalation by the public and balneary workers, as well as the chemical and radiological characterization for these spas were evaluated. 222Rn activity concentration was measured by using CR-39, elemental water composition by neutron activation, and radionuclides, by gamma espectrometry. Results showed that the 222Rn activity concentration varied from 21 to 71 Bq m−3 in the public areas of the balnearies and from 407 to 16,451 Bq m−3 in the closed springs. Effective doses varied from 0.01 to 0.02 mSv y−1 for the public, from 0.10 to 0.33 mSv y−1 for works and from 0.03 to 4.95 mSv y−1 for maintenance. No risk occurs for members of the public and workers due to radon inhalation, but care must be taken on behalf of the maintenance workers from Águas de Lindóia balneary. The water, for both balnearies, do not exceed the recommendation for drinking water for gross alpha and gross beta activities. Chemically, the water from Águas de Lindóia is classified as hypo saline and the water from Poços de Caldas, as low mineral content.