Gamma dosimetry of the uranium deposit in Sao Jose de Espinharas, Paraiba, Brazil

Radioecology studies contribute to the monitoring of both anthropic and natural radionuclides, as well as their correlation with the ecosystem and the population. Terrestrial sources, which mainly include the primary radionuclides of the 238U, 232Th, and 40K series, contribute to a higher effective dose received by humanity, with 84% from terrestrial radionuclides and another 16% derived from cosmogenic nuclides. Areas with high levels of natural radiation, above the acceptable limits, are of great relevance for the development of dosimetry studies, whose core aims include the preservation of the environment and the control of the population's exposure to radiation. The town of Sao Jose de Espinharas, Paraiba, Brazil, has a uranium oxide mine with an average grade of 1,200 mg/kg. In the present study, non-destructive, in situ assays were performed along the entire radiometrically anomalous area. The results obtained in terms of effective doses varied from 3.79 to 93.80 mSv.y-1, with an average of 19.47 mSv.y-1 thus leading to the conclusion that all of the monitored points presented environmental doses of above the reference value of 2.4 mSv.y-1, suggesting that both qualitative and quantitative analyses concerning the environmental matrixes in question need to be performed. (author)