The present work deals with estimation and distribution of natural radionuclides in 40 soil samples collected from Wadi Al-Rummah (Qassim part) Central Saudi Arabia. Estimations were carried out using NaI (Tl) gamma-ray spectrometer. Activity concentrations ranged from 5.3 to 45.0 Bq kg-1, from 4.3 to 33.8 Bq kg-1 and from 38 Bq kg-1 to 273.1 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The average activity concentrations of 226Ra, 232Th and 40K in soil samples was 15.5 Bq kg-1, 14.1 Bq kg-1 and 143.1 Bq kg-1. The results of this study were compared with other studies around the world. Radiation hazard parameters such as radium equivalent activity, annual dose, external hazard were calculated and compared with the recommended levels quoted from International Commission on Radiological Protection (ICRP-60) and United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR reports.
Keywords: Natural radioactivity levels; adium equivalent; Radiation hazards soil.