Measurements of Natural Radioactivity Levels in Soil Samples and Hazards in Lega Dembi Gold Mining, East Guji, Oromia, Ethiopia.

Abstract The fifteen common soil samples in Lega Dembi were collected to determine the amount of natural radiation released and its effects on humans. This is the first time that such research has been conducted. The natural radionuclide contents in soil were determined using HPGe gamma-ray spectrometry. It was observed that the mean activity for 226Ra, 232Th, and 40K determined in the mining site were 23.87±0.7, 52.5±1.8, and 391.62±11.35 Bq/kg while in the living areas were 8.89±0.4, 13.83±0.6 and 423.68±9.5 respectively. The activity of 232Th was above the world mean average limit in the mining site; whereas for 226Ra and 40K were lower than the world limit. The activity concentration of 40K in the living area was higher than the world limit however 226Ra and 232Th were lower than the limit. The mean annual effective dose was lower than the world average limit. The calculated absorbed dose rate in the mining site was higher than the world average. The gamma activity index values were 0.94±0.05, and 0.48±0.06 for the mining and living site respectively. The gamma index had lower than the world means values. The mean annual gonadal dose equivalent value was found to be 494.8±8.7 lµSv/year in the mining site.