Measurement of natural radioactivity in the clays consummated in côte d'Ivoire using gamma-ray spectrometry

Abstract

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 Cote d'lvoire for their therapeutic virtues by using gamma spectrometry. The activity concentration of 226Ra, 232Th and 40K ranged from 19.0±8.2 to 54.8±20.8 Bq kg1 (with a mean of 33.6±13.2Bqkg-1),froml2.8±3.5to42.3±12.1Bqkg-1(withameanof31.3±8.5Bqkg-1)andfroml6.0±59.2to 790±245 Bqkg1 (with a mean of 314.1±101.7 Bqkg1), respectively. Radium equivalent activities and various hazard indices were also calculated to assess the radiation hazard. The Radium equivalent activity (Raeq) ranged from 90.2±28.4to 130.3±43.8 Bqkg1 (with an average of 102.6±33.1 Bqkg1), was lower than the limit of 370 Bqkg1. The calculated values of external hazard index (FLJ 0.24±0.08-0.35±0.12 and internal hazard index (FLJ 0.32±0.11-0.50±0.18 were also lower than unity. The annual effective dose ranged from 52.2±16.3 to 73.8±24.8 uSv y1 with a mean of 59.6±19.1 uSv y1 whereas the effective dose by ingestion varied from 17.1±6.2 to 30.8±11.1 uSv y1 with an average of 21.3±7.6 uSv y1. These values were lower than the limit of 1 mSv y1. From this study, it was found that the use of the investigated clay samples for their therapeutic virtues did not induce significant radiation hazards. © 2013 Asian Network for Scientific Information.