Research Center for Radiation Protection, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan.
Health Phys. 2013 Jan;104(1):41-50. doi: 10.1097/HP.0b013e3182611a06.
In Japan, many dwellings have decorative wall coverings made from granite, andesite, tuff, gabbro, and marble. However, information regarding activity concentrations and radon (Rn) and thoron (Rn) exhalation rates for such rocks is very scarce. Therefore, samples of the granite, andesite, tuff, and marble that are used as wall coverings in Japan were collected from mining companies, and their activity concentrations and Rn and Rn exhalation rates were measured. Dose estimations for inhabitants living in houses built with these materials were also carried out. The activity concentration of natural radionuclides in all the materials was lower than the critical values described by the International Atomic Energy Agency (IAEA) (10,000 Bq kg for K and 1,000 Bq kg for all other radionuclides of natural origin). The maximum values of Rn and Rn mass exhalation rates for the granite samples were 0.12 and 430 mBq kg s, and those for the area exhalation rates were 1.8 and 6300 mBq m s, respectively; these values are higher than those for other samples. The maximum value of effective doses to inhabitants was 0.68 mSv y, which is lower than the intervention exemption level (1 mSv y) given in the International Commission on Radiological Protection (ICRP) Publication 82.
在日本，许多住宅都使用花岗岩、安山岩、凝灰岩、辉长岩和大理石等作为装饰性的墙壁覆盖物。然而，关于这些岩石的活度浓度以及氡（Rn）和钍（Rn）析出率的信息非常有限。因此，从日本的石材开采公司收集了用作墙壁覆盖物的花岗岩、安山岩、凝灰岩和大理石样品，并测量了它们的活度浓度以及氡和钍的析出率。同时，还对居住在使用这些材料建造的房屋中的居民进行了剂量估算。所有材料中的天然放射性核素活度浓度均低于国际原子能机构（IAEA）规定的临界值（K 的临界值为 10000 Bq kg，所有其他天然放射性核素的临界值为 1000 Bq kg）。花岗岩样品的氡和钍质量析出率的最大值分别为 0.12 和 430 mBq kg s，而面积析出率的最大值分别为 1.8 和 6300 mBq m s，这些值均高于其他样品。居民的有效剂量最大值为 0.68 mSv y，低于国际放射防护委员会（ICRP）第 82 号出版物中规定的干预豁免水平（1 mSv y）。
