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High natural radiation in Brazilian sands

Abstract:

The present work investigated Brazilian beach sands in order to analyze the total external natural radiation dose using a gamma-ray spectrometry technique. The activities from the radionuclides 40K and the elements from the series of 238U and 232Th were measured. The sand samples from Morro Branco beach, Ceará, and Itacaré beach, Bahia, presented different colors and grain size than the beaches from São Paulo. A sample collected in Itacaré beach showed an effective dose of 2.5 (1) mSv/yr. This value is outside the annual typical range (0.3-0.6 mSv) indicated by the United Nations Scientific Committee on the Effects of Atomic Radiation. The high effective dose found in Itacaré beach is mainly due to the presence of a large amount of 232Th and 238U. All the other samples collected in Ceará and São Paulo States are inside the annual typical range. Energy-Dispersive X-Ray Spectroscopy (EDS …