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 238U, 232Th and 40K 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 238U, 232Th and 40K in soil and sediment samples was determined by gamma spectrometry using the HPGe semiconductor detector. Obtained activity concentrations ranged from 28.0 to 44.0Bq/kg for 238U, from 59.4 to 71.4Bq/kg for 232Th and from 335.0 to 517.0Bq/kg for 40K. The evaluation of the radiological hazards originated from 238U, 232Th and 40K 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. ► Radionuclides 238U, 232Th and 40K in different profile of soil are measured. ► Gamma spectrometry specific activity of radionuclides was determined. ► Correlation between the physical–chemical parameters of soil and natural radionuclides is important. ► Concentrations of radionuclides are not extremely changed at the profiles.