Article

Determination of ²²⁶Ra, ²³²Th, ⁴⁰K and ²³⁵U in soil samples from bauxite core deposits in western Cameroon

¹ Fundamental Physics Laboratory, UFD Mathematics, Applied Computer Sciences and Fundamental Physics, University of Douala, P.O.Box 24157 Douala, Cameroon.
² The National Radiation Protection Agency, P.O.Box 33732, Yaounde, Cameroon.
³ Graduate School of Nuclear and Allied Science, P.O. Box AE1, Accra, Ghana.

Received: 23 December 2015
Accepted: 17 June 2016

Abstract

The activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and ²³⁵U in soil samples from a bauxite ore deposit site in Western Cameroon were determined by gamma spectrometry using a Broad-Energy Germanium (BEGe6350) detector. The average activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰K and ²³⁵U were found to be 124.8 ± 58.1, 157.3 ± 67.3, 670.9 ± 272.3 and 5.8 ± 2.7 Bq kg^-1, respectively. The measured activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K were compared with available data in some countries and the world average activity concentration of soil. The radiological hazard indices of radioactivity were calculated, with average values of 416.90 Bq kg^-1 for the radium equivalent activity, 188.20 nGy h^-1 for the gamma radiation dose rate, 0.23 mSv y^-1 for the external outdoor annual effective dose, 0.92 mSv y^-1 for the indoor annual effective dose, 1.02 mSv y^-1 for the total annual effective dose and 1.13 for the external hazard index, respectively. These radiological hazard index values were also compared with the internationally approved values. Consequently, use of concrete bricks made of soil as building materials might lead to an increased radiation risk for the population of Fongo-Tongo.