@article{oai:repo.qst.go.jp:00046875,
 author = {Iwaoka, Kazuki and Hosoda, Masahiro and Tabe, Hiroyuki and Ishikawa, Tetsuo and Tokonami, Shinji and Yonehara, Hidenori and 岩岡 和輝 and 田部 裕章 and 石川 徹夫 and 米原 英典},
 issue = {1},
 journal = {Health Physics},
 month = {Jan},
 note = {In Japan, many dwellings have decorative wall coverings
made from granite, andesite, tuff, gabbro, and marble.
However, information regarding activity concentrations and
radon (222Rn) and thoron (220Rn) 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 222Rn and 220Rn 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 kgj1 for 40K and 1,000 Bq kgj1
for all other radionuclides of natural origin). The maximum values
of 222Rn and 220Rn mass exhalation rates for the granite
samples were 0.12 and 430 mBq kgj1 sj1, and those for the area
exhalation rates were 1.8 and 6300 mBq mj2 sj1, respectively;
these values are higher than those for other samples. The maximum
value of effective doses to inhabitants was 0.68 mSv yj1,
which is lower than the intervention exemption level (1 mSv yj1)
given in the International Commission on Radiological Protection
(ICRP) Publication 82.},
 pages = {41--50},
 title = {Activity concentration of natural radionuclides and radon and thoron exhalation rates in rocks used as decorative wall coverings in Japan},
 volume = {104},
 year = {2013}
}