山陰地方の温泉水中の²³⁸U, ²³⁴U, ²²⁶Raおよび²²⁸Ra含有量について

抄録

The ²³⁸U, ²³⁴U, ²²⁶Ra and ²²⁸Ra concentrations in the spring waters at the Sanbe and Misasa districts in Japan were investigated. In the spring water at Sanbe, high concentrations of the natural nuclides described above were found in which the maximum levels of ²³⁸U and ²³⁴U were 0.44 Bq/l and 0.91 Bq/l, respectively, while ²³⁴U/²³⁸U showed the range of 1.50-2.37. The maximum levels of ²²⁶Ra and ²²⁸Ra were found to be 1.95 Bq/l and 0.76 Bq/l, respectively, while ²²⁸Ra/²²⁶Ra mean value was 0.49. In the spring water at Misasa, the maximum levels of ²²⁶Ra and ²²⁸Ra were 0.60 Bq/l and 0.41 Bq/l, respectively, and ²²⁸Ra/²²⁶Ra mean value was 0.55. From the above-mentioned result and the fact that ²²⁸Ra is a decayed product of ²³²Th, it is thought that the rocks of the Sanbe and Misasa districts contain much uranium and thorium.