Radioactivity in zircon and building tiles

Journal Article · Fri Aug 01 04:00:00 EDT 1997 · Health Physics

OSTI ID:585249

Deng, Wen; Tian, Kaizhen; Chen, Daifu ^[1]; Zhang, Yiyun ^[2]

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1. Sichuan Institute of Labor Hygiene, Chendu (China)
2. Sichuan United Univ., Chengdu (China)

Zircon (ZrSiO{sub 4}) is commonly used in The manufacture of glazed tiles. In this study we found high concentrations of the radionuclides {sup 226}Ra, {sup 232}tH, {sup 40}k in zircon sand. The average radium equivalent (A{sub Ra} + 1.26 A{sub Th} + 0.086 A{sub k}) in zircon sand is 17,500 Bq kg{sup -1}, which is 106 times as much as that in ordinary building materials. The external radiation ({gamma} + {beta}) dose rates from 1.1 to 4.9 x 10{sup -2} mGy h{sup -1} with an average of 2.1 x 10{sup -2} mGy h{sup -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}, {beta} and {gamma} emitting thin materials, the average {gamma} 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 {beta} emitting radionuclides in glazed floor tiles and glazed wall tiles is 0.30 Bq cm{sup -2} and 0.28 Bq cm{sup -2}, respectively. It was estimated that the average {beta} dose rates in tissue at a depth 7 mg cm{sup -2} with a distance 20-100 cm from the floor tiles were 3.2 to 0.9 x 10{sup -7} Gy h{sup -1}. The study indicates that the {beta}-rays from glazed tiles might be one of the main factors leading to an increase in ionizing radiation received by the general public. Workers in glazed tile manufacturing factories and in tile shops or stores may be exposed to elevated levels of both {beta}-rays and {gamma}-rays from zircon sand or glazed tile stacks. No elevated radiation from unglazed tiles was detected. 10 refs., 1 fig., 3 tabs.

• OSTI ID: 585249
• Journal Information: Health Physics, Journal Name: Health Physics Journal Issue: 2 Vol. 73; ISSN HLTPAO; ISSN 0017-9078
• Country of Publication: United States
• Language: English

Related Subjects

56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BUILDING MATERIALS
DOSE RATES
EXHALATION
GAMMA RADIATION
OCCUPATIONAL EXPOSURE
POTASSIUM 40
RADIATION DOSES
RADIUM 226
THORIUM 232
ZIRCON