Naturally Occurring Radionuclides in Tiles Available in Ibadan, Nigeria, and the Associated Radiological Hazards.

INTRODUCTION: All building materials of natural origin contain some amounts of primordial radionuclides, 40 K, 232 Th, and 238 U, as well as other radionuclides in the decay series of 232 Th and 238 U.

PURPOSE: The use of tiles to beautify walls and floors in dwellings has become popular worldwide and in Nigeria in particular. However, not much has been done in assessing the impact of the use of floor and wall tiles on the radiation exposure of dwellers. In this study, radioisotopes of natural origin (226 Ra, 232 Th, and 40 K) in selected ceramic tiles often used in Ibadan Southwest Nigeria were estimated and the associated radiological parameters evaluated.

METHODOLOGY: Forty-five samples of different types of floor and wall tiles were obtained from local markets within the study area. Each of the 45 samples was pulverized and sealed in an airtight sample container for 4 weeks before analysis using a sodium iodide-based gamma-ray spectrometer.

RESULTS: The average values of 226 Ra, 232 Th, and 40 K obtained were 44.28 ± 0.56, 84.71 ± 0.60, and 830.44 ± 0.63 Bqkg-1 , respectively, which shows that they are greater than the corresponding estimated worldwide average concentration. Again, the estimated average values obtained for the radiological hazard parameters for equivalent activity due to radium and representative gamma-ray level index were found to be lower than the world averages. Similarly, the absorbed dose rates due to gamma-ray emission were found to be higher than the world common values.

CONCLUSION: This study indicates that the use of these tiles will not be posing potential radiological risk if used in dwellings. However, construction works that requires the use of these tiles must be designed in such a way that the emission of dangerous radiation will not be a threat to the occupants.