Revisiting Natural Radiation in Itacaré and Guarapari Beaches

Human beings are constantly exposed to several types of natural radiation. This paper aims to study the total external dose from northwestern Brazilian beach sands. The samples were collected at Prainha in Itacaré, Bahia, and Praia de AreiaPreta in Guarapari, Espírito Santo. Gamma spectrometry is a very useful technique to estimate the effective dose due to naturally occurring radionuclides, such as 40K and daughters of 238U and 232Th. In order to confirm the high activity present in these two regions, the effective dose due to each natural radionuclide was determined. Moreover, the Energy-Dispersive X-Ray Spectroscopy (EDS) microanalysis was used to characterize the soil composition and the minerals responsible for the high activity. In addition, the sand samples were separated in to magnetic and non-magnetic fractions in order to identify the contribution from each portion of the activity. Finally, the radionuclides and their dispersion in those places are consistent with previous studies, indicating effective doses above the world average that is between 0.3 mSv/year and 1.0 mSv/year.