Geoprocessing as a technical tool for radiological assessment in the urban area of Pocos de Caldas, MG

The present study will introduce a methodology for spatial evaluation of external gamma dose throughout an urbanized region. As a case study, geoprocessing techniques were used to gather data, perform statistical and spatial data treatment related to natural gamma radioactivity throughout the Pocos de Caldas urban area. This information, which was initially punctual, could be correlated with the number of people exposed to natural radiation using the database from the census made available by IBGE (Brazilian Geography and Statistics Institute). The census sector is the smallest piece of territory, with identifiable physical boundaries in the field, with adequate size for research operations. All 54,237 geoprocessed external dose values, within dosimetry ranges, presented a variation from 0.33 mSv year-1 to 3.51 mSv year-1, with an average equal to 0.95 mSv year-1. The results obtained, when compared to worldwide dose values (0.06 mSv year-1 to 1.23 mSv year-1 with an average of 0.48 mSv year-1) indicated that though the average value in Pocos de Caldas - 0.95 mSv year-1 - is almost twice the world average, it is within the dosimetry range found in other countries. Nevertheless, the region has some areas with values higher than those observed elsewhere in the world, though in areas with lower population density. (author)