Determination of factors affecting indoor doses from Malaysia’s ceramic tiles containing natural radionuclides

Abstract

Abstract The level of natural radioactivity and radiological risks attributed to forty (40) different ceramic tiles using gamma-ray spectroscopy employing high-purity germanium detector were studied. The average activity concentrations of 226Ra, 232Th and 40K range from 37.5 ± 0.3 to 215.9 ± 5.8 Bq kg−1, 42.2 ± 0.1 to 181.8 ± 3.8 Bq kg−1 and 349.5 ± 25 to 1589.2 ± 21.1 Bq kg−1, respectively. The radium equivalent activity and activity concentration index were calculated to estimate the potential radiological hazards to the dweller. Furthermore, the factors affecting the total effective dose equivalent (TEDE) such as ventilation rate, room size and dweller position were investigated from the measured activity concentrations using RESRAD-BUILD computer code. The simulation results of TEDE from the variations of ventilation rate in a room range from 0.26±0.01 to 0.61±0.01 mSv y−1, on the other hand, the percentage variation of TEDE due to dweller position and room size are 35% and 33%, respectively. The calculated radiological risks parameters were all below the recommended maximum limit. Therefore, the radiological impact attributed from the ceramic tiles under study is negligible.