This study was conducted in an area of 14 km in length oriented in the NNE direction by 7.3 km wide, covering the totality of the Serra do CarambeíGranite and adjacent units. Located in the northern region of the Alagados dam, Paraná State, this granite contains relatively high concentrations of K, eU and eTh, known since the 1970s through airborne and terrestrial gamma-ray spectrometry surveys. Recent radiochemical tests conducted on 61 samples of geological materials such as rocks (17 samples) and material of the weathering mantle and alluvial deposits (44 samples), confirmed the occurrence of radioactive anomalies in this granite, especially in thorium and uranium. The contents of K, eU and eTh obtained in gamma-ray spectrometry survey and radiochemical tests, converted to annual radiation dose (ARD), allowed to evaluate the intensity of natural radiation, whose levels relatively high in certain regions of the study area, can offer hazard to the local populations. The analysis and interpretation of data, as well the preparation of contour maps of K, eU and eTh were fundamental to understand the behavior and mobility of radionuclides in different environmental compartments of the area.
Serra do Carambeí Granite; gamma-ray spectrometry; radiochemical analysis; annual radiation dose
