Influence of Paraiba uranium deposit in the evaluation of radioecological dosimetry from Sao Mamede- PB

Regions with different levels of natural radionuclides should be investigated from the radioecological viewpoint, to establish protection criteria for environment and the population. The municipality of São Mamede in the state of Paraiba, is one of the closest of the uranium deposit in Espinharas - PB, and can be influenced, given its geological formation, which justifies conducting environmental dosimetric studies. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) established in 2008 a value for the environmental equivalent effective dose rate of 2.44 mSv / y, considering the different forms of exposure and outdoor environments and internal. The calculation for estimating the outdoor dose rate considered a factor of 0.2, which corresponds therefore to a dose rate of 0.46 mSv / y for these environments. The objective of this study was to determine the levels of natural ionizing radiation that municipality using estimated effective dose rate measured in air and 1.0 m from the surface, points to the presence of rocky outcrops using portable detector with discriminator combined probe of NaI (Tl) and BGO. The experimental setup allowed the evaluation of eighty-one points, dose rates ranged from 0.34 to 4.0 mSv / y, with an average of 0.76 mSv / y, exceeding the global average by a factor of 9, which characterizes the need to investigate the dosimetry for internal environments, which can define criteria to check a possible estimate of radioecological risk. (author)