Radon exhalation and health hazard assessment for various ceramic tiles used in Bangladesh

Abstract

Objective: Among various building materials, tiles are the most used decorative materials used worldwide. For the safe use of tiles at home and workplace it is required to select them properly based on radiation dose due to radon and gamma emission.
 Experiments: Among various tiles available in the market, 25 different types of tiles were collected for this experiment. Collected tiles are then ground and stored in sealed cans for secular equilibrium. To measure gamma activity due to the radionuclides 226Ra, 232Th, 40K, High Purity Germanium (HPGe) detector was used. To store radon gas emitting from tiles, a big box was used. The activity concentration was then measured by a radon detector (RadonEye) by placing it inside the box.
 Results and discussion: It was observed that 226Ra, 232Th, 40K activity varies from 45 – 89 Bq/Kg, 77 – 110 Bq/Kg, and 321 – 694 Bq/Kg. The radium equivalent activity varies from 198.32 – 280.46 Bq/Kg, less than the recommended value of 370 Bq/Kg set by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). The activity concentration of radon varies from 31 – 71 Bq/m3. This is lower than the 300 Bq/m3 recommended by ICRP (International Commission on Radiological Protection). The radon exhalation rate varies from 0.179 – 0.409 Bqm−2h−1. To assess radiological hazards associated with the tiles samples air absorbed dose rate, internal and external hazard index, gamma index, annual indoor and outdoor effective dose rate, and dose due to radon were also calculated.
 Conclusion: Though the estimated values for external and internal hazards are below the recommended values, they may be safe for adults. As children have thinner skin and breathe more air due to high breathing frequency, they may receive more radiation than adults. Moreover, they are at a greater risk because of their developing bodies and long life expectancy post-exposure.