D. AYALEW, B. SITOTAW#, E. MENGISTU
Department of Physics, Dire Dawa University, Ethiopia
Assessment of the level of radioactivity from radionuclides in soil is important for the assessment of the exposure to natural radiation. Sixteen samples from soil were collected from different sites of Dire Dawa city and the level of natural radioactivity was measured using gamma-ray spectrometry based on a high purity germanium (HPGe) detector. Radiation hazard indices were calculated to evaluate the radiological risk for the public and environment. The results show that the mean value of radium equivalent activity is 246.5±9.6 Bq·kg−1, while the values of absorbed dose rate and annual effective dose equivalent are 73 nGy·h−1 and 89.72 mSv·y−1 respectively. The values of external and internal health hazard indices are 0.12 and 0.83 respectively which is less than the permitted values in all samples, while the values of gamma index is 0.59 is less than the permitted limit. In general, there are no harmful radiations effects posed to the population who live in the study area; however, that exceed the internationally accepted values.
Key words: HPGe, absorbed dose, annual effective, hazard indices, gamma indices
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