Vertical distribution of natural radionuclides in soil: Assessment of external exposure of population in cultivated and undisturbed areas

In the present work, naturally occurring radionuclides U-238, Th-232 and K-40 were measured in soil samples from the cultivated and undisturbed areas in Rudovci, municipality of Lazarevac, Serbia. There were three profiles, each profile divided into four horizons, giving the twelve soil samples. The specific activity of U-238, Th-232 and K-40 in soil and sediment samples was determined by gamma spectrometry using the HPGe semiconductor detector. Obtained activity concentrations ranged from 28.0 to 44.0 Bq/kg for U-238, from 59.4 to 71.4 Bq/kg for Th-232 and from 335.0 to 517.0 Bq/kg for K-40. The evaluation of the radiological hazards originated from U-238, Th-232 and K-40 in the samples, the absorbed dose rate (D) and the annual effective dose rate (E), calculated in accordance with the UNSCEAR 2000 report, are presented in this paper. (C) 2012 Elsevier B.V. All rights reserved.