Caracterización radiológica y cálculo de la exposición externa de las aguas termales de la provincia de Tungurahua utilizando espectrometría gamma.

Abstract

The present investigation had as objective the radiological characterization of the thermal springs of the province of Tungurahua and the calculation of the external exposure that receives the population due to these waters. In this exploratory study, a single simple type sampling of the 19 most important thermal sources of the entire province was carried out, with the collection of physical chemical variables in situ, also a chemical treatment with nitric acid was given to preserve the samples until its measurement. Radioactivity of the water samples was performed, first the concentration of total activity generated by the radioactive decay of alpha and beta emitters with alpha / beta counter equipment based on a silver doped zinc sulphide scintillator. Finding values of up to 2.45 Bq / L in gross alpha emissions and values of up to 0,440 Bq / L in gross beta emissions, as maximum values; in several samples it was considered th at theradioactivity was in amounts not detectable by the equipment used. Gamma emission spectra were obtained from the thermal springs using a gamma spectrometer with a pure germanium coaxial detector (HPGE). The gamma-emitting radioisotopes of each sample were identified and quantified: lead 214 ( 214 Pb), bismuth 214 ( 214 Bi), polonium 210 ( 210 Po), potassium 40 (40 K) and actinium 228 ( 228 Ac).With concentrations from 2.5 Bq / L up to 281 Bq / L. When calculating the effective dose by external exposure received by the presence of these radioisotopes, it was concluded that there is no radioactive risk for the population that uses these spas. It is recommended to make a more exhaustive analysis of the "El Salado" spa located in Baños because it was the site where more radioactive elements were found and where more anomalous values were found than in the rest of the thermal springs.