Assessment of Gamma Radiation 232Th, 226Ra and 40K in Nassarawa, Nigeria
U. Rilwan *
Department of Physics, Nigerian Army University, P.M.B. 1500, Biu, Borno State, Nigeria.
I. Umar
Department of Physics, Nasarawa State University, P.M.B. 1022, Keffi, Nasarawa State, Nigeria.
A. Z. Ngari
Department of Physics, Nigerian Army University, P.M.B. 1500, Biu, Borno State, Nigeria.
H. A. Abdullahi
National Agency for Science and Engineering Infrastructure, Idu Industrial Area, P.M.B 391, Garki, Abuja-Nigeria.
H. O. Aboh
Department of Physics, Nigerian Army University, P.M.B. 1500, Biu, Borno State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study assessed gamma radiation from 232Th, 226Ra and 40K. Twelve soil samples collected from the study area were analyzed using Nal (TI) detector. Mean concentration for 40K, 232Th and 226Ra were found to be 483.97±7.32 Bq/kg, 28.43±5.30 Bq/kgS and 66.84±2.02 Bq/kg respectively. Absorbed Dose Rate ranged from 44.85 nGy/h to 90.71 nGy/h with a mean of 73.68 nGy/h. Effective Dose Rate ranged from 0.055 to 0.111 msv/yr with a mean of 0.090 mSv/y. The Internal and External Hazard Indices ranged from 0.271 to 0.533 Bq/kg with the mean of 0.435 Bq/kg and 0.289 to 0.675 Bq/kg with the mean of 0.512 Bq/kg respectively. It can thus be concluded that the radiation dose of the study area is minimal and seems to have low exposure for the inhabitants in and around the contaminated areas. It is therefore recommended that regular radiation monitoring exercises should be conducted on the processing sites to prevent the inhabitants of the area from high radiation exposure due to direct inhalation of finely divided particulates and dust comprised of the above-mentioned radionuclides.
Keywords: Soil, mining, columbite, radionuclide, health absorbed dose, effective dose, radium equivalent activity, external and internal hazard index and γ-ray spectrometry.