Measurement of Natural Radioactivity in the Clays Consummated in Cte dIvoire using Gamma-ray Spectrometry

The presence of radionuclides in natural materials was one of the major causes of external and internal exposure to ionizing radiation (gamma rays). The knowledge of the radioactivity levels in these commonly used materials was of great importance in the assessment of possible radiological risks to human health. The purpose of this study was to determine the natural radioactivity due to 226Ra, 232Th and 40K of some clay samples consummated in Cte dIvoire for their therapeutic virtues by using gamma spectrometry. The activity concentration of 226Ra, 232Th and 40K ranged from 19.08.2 to 54.820.8 Bq kg-1 (with a mean of 33.613.2 Bq kg-1), from 12.83.5 to 42.312.1 Bq kg-1 (with a mean of 31.38.5 Bq kg-1) and from 16.059.2 to 790245 Bq kg-1 (with a mean of 314.1101.7 Bq kg-1), respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The Radium equivalent activity (Raeq) ranged from 90.228.4 to 130.343.8 Bq kg-1 (with an average of 102.633.1 Bq kg-1), was lower than the limit of 370 Bq kg-1. The calculated values of external hazard index (Hex) 0.240.08-0.350.12 and internal hazard index (Hin) 0.320.11-0.500.18 were also lower than unity. The annual effective dose ranged from 52.216.3 to 73.824.8 Sv y-1 with a mean of 59.619.1 Sv y-1 whereas the effective dose by ingestion varied from 17.16.2 to 30.811.1 Sv y-1 with an average of 21.37.6 Sv y-1. These values were lower than the limit of 1 mSv y-1. From this study, it was found that the use of the investigated clay samples for their therapeutic virtues did not induce significant radiation hazards.