Radioactivity in zircon and building tiles.
Zircon (ZrSiO4) is commonly used in the manufacture of glazed tiles.
In this study we found high concentrations of the radionuclides 226Ra, 232Th, 40K in zircon sand.
The average radium equivalent (ARa+1.26 ATh+0.086 Ak) in zircon sand is 17,500 Bq kg-1, which is 106 times as much as that in ordinary building materials.
The external radiation (gamma+bêta) dose rates in air at 5 cm from the surface of piles of zircon sand sacks range from 1.1 to 4.9 x 10-2 mGy h-1 with an average of 2.1 x 10-2 mGy h-1.
Although no elevated gamma-ray radiation or radon exhalation rate was detected in rooms decorated with glazed tiles, which is characteristic of combined alpha, bêta and gamma emitting thin materials, the average gamma-ray radiation dose rate at the surface of the tile stacks in shops is 1.5 times as much as the indoor background level.
The average area density of total bêta emitting radionuclides in glazed floor tiles and glazed wall tiles is 0.30 Bq cm-2 and 0.28 Bq cm-2, respectively.
It was estimated that the average bêta dose rates in tissue at a depth 7 mg cm-2 with a distance 20-100 cm from the floor tiles were 3.2 to 0.9 x 10-7 Gy h-1.
The study indicates that the bêta-rays from glazed tiles might be one of the main factors leading to an increase in ionizing radiation received by the general public. (...)
Mots-clés Pascal : Zircon, Cloison vitrée, Matériau construction, Analyse quantitative, Radon, Analyse risque, Potassium, Radiocontamination, Thorium, Rayonnement ionisant, Emetteur bêta
Mots-clés Pascal anglais : Zircon, Glazed partition, Construction materials, Quantitative analysis, Radon, Risk analysis, Potassium, Radioactive contamination, Thorium, Ionizing radiation, Beta emitter
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 97-0431967
Code Inist : 002A08F02. Création : 19/12/1997.