Abstract
The mining activity may have potential radiological hazards due to the presence of primordial radionuclides associated with the exploited ore. In northeastern of Brazil, kaolin mining companies are mainly located in the region of Borborema-Seridó Pegmatitic Province located between the states of Paraíba and Rio Grande do Norte. The kaolinite ore brings aggregate materials formed by elements belonging to the series of U-238 and Th-232, beyond K-40. The presence of these natural radioisotopes can confer high levels of ionizing radiation associated with the material extracted from the mines. The UNSCEAR reports the global average effective dose of exposure to natural sources radiation as 2.42 mSv.y-1. National and international studies have shown that the activity of kaolin may exceed the global averages. This study aimed the radiometric mapping of kaolin exploration areas in the Seridó region due to its proximity to uranium deposits. A scintillator detector of NaI (Tl) was used to perform effective dose rate measurements in the vicinity of four mines in the region, and values that ranged from 1.37 to 2.94 mSv.y-1 were obtained. The results suggest a need for a deeper approach such as obtaining soil and rock samples for more analyzes.
Keywords:
ionizing radiation; radiometric mapping; natural radionuclides
