Abstract
We have studied the leaching rate of the radionuclides from the natural radioactive minerals, however, the composition of those minerals have been unknown. Hence, the composition of the minerals were investigated and the relationship between the chemical compounds in the minerals and leached radionuclides from the minerals was studied. The samples were obtained from the gallery of Badgastein and the hot bathroom with a high concentration of radon at Misasa Medical Center of Okayama University Medical School. The activities of the samples and the leached solution from the samples were measured by the high-purity germanium detector. The samples were identified by an elemental analysis and an x-ray diffraction. The activities of the mineral of Badgastein and the sludge of Misasa were 12 and 2.1 Bq/g, respectively. The activities almost arose from the uranium series. The activities of the leaching nuclides in the mineral of Badgastein were smaller than those in the sludge of Misasa. The mineral of Badgastein includes quartz and muscovite and the sludge of Misasa includes quartz and albite related minerals. The muscovite includes potassium whose ion radius is similar to that of radium and the albite related minerals include alkali metals whose ion radii are similar to those of the radionuclides. The radionuclides may substitute for these alkali metals and the samples contain the activities. The chemical compounds in the minerals may affect the leaching rate of the radionuclides of the samples.
