Determination of 226Ra 232Th 40K 235U and 238U activity concentration and public dose assessment in soil samples from bauxite core deposits in Western Cameroon

摘要

Determination of activity concentrations in twenty five (25) soil samples collected from various points in bauxite ore deposit in Menoua Division in Western of Cameroon was done using gamma spectrometry based Broad Energy Germanium (BEGe6530) detector. The average terrestrial radionuclides of ⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁵U and ²³⁸U were measured as 671 ± 272, 125 ± 58, 157 ± 67, 6 ± 3 and 99 ± 69 Bq kg⁻¹, respectively. The observed activity concentrations of radionuclides were compared with other published values in the world. The outdoor absorbed dose rate in air varied from 96.1 to 321.2 nGy h⁻¹ with an average of 188.2 ± 59.4 nGy h⁻¹. The external annual effective dose rate and external hazard index were estimated as 0.23 ± 0.07 mSv year⁻¹ for outdoor, 0.92 ± 0.29 mSv year⁻¹ for indoor and 1.13 for the external hazard index, respectively. These radiological safe parameters were relatively higher than the recommended safe limits of UNSCEAR. Consequently, using of soil as building material might lead to an increase the external exposure to natural radioactivity and future applications research need to be conducted to have a global view of radioactivity level in the area before any undergoing bauxite ore exploitation.