Determinations of Naturally Occurring Radioactive Materials’ Concentration Levels and Health Risk in Agricultural Soil of West Guji Zone, in Case of Bule Hora Woreda, Ethiopia

The primary sources of naturally occurring radioactivity in the soils are Th-232, U-238, their nuclear progenitor, and K-40. In this study, the concentration of naturally occurring radionuclides K-40, U-238, and Th-232 and their health risks were determined from 7 agricultural soil samples collected from some randomly selected kebeles in West Guji Zone, Bule Hora Woreda's, by using a High –purity germanium detector(HPGe). Sample collection, preparation, and analysis followed the recommended international procedures. Specifically, radium equivalent activity and radiological parameters were calculated and compared with international recommended limits. The average radioactivity concentrations of K-40, U-238, Th-232 and Cs-137 were 319.8±15.7 Bq/kg, 29.03±1.51Bq/kg, 53.1±3.05Bq/kg, and 0.36±0.04Bq/kg, respectively. The average values of radium equivalent activity, absorbed dose rate, annual effective dose, external and internal hazard indices and representative level index were 229.6±7.07 Bq/kg,71.04± 3.39 nGy/h, 0.42±0.0196mSv/y, 0.35±0.019, 0.37±0.021 and 0.47±0.03, respectively. The activity concentration of Th-232 is greater than the world average value. The radiation hazard indices found in this study were less than the world average value. The absorbed dose rate is greater than the world average value in the study area.