The chemical and physical characteristics of the thermal and ground waters in Sekigane Hot Springs were determined. The content of the following chemical constituents was determined: Cl(-), S0(4)(2-), HCO(3)(-), Ca(2+), As, F, U and Ra. The relationship between water temperature and depth of spring wens was found to be indicative of the presence of a fissure, in agreement with the conclusion reached geologically by Sugiyama. The water temperature, the e1ectricconductivity and the content of chemical constituents of the ground water were as expected markedly lower than those of the thermal water. As a whole, however, the water temperature, the electricconductivity
and the content of SO(4)(2-), HCO(3)(-), Ca(2+), As and F are in positive and linear correlation
with the Cl- content. In other words, these characteristics of the waters, excluding the U and Ra content, correlate positively and linearly with each other. This was interpreted to mean that a thermal water of high salinity is simply diluted by a cold ground water of very low salinity, and that a ground water of relatively high salinity is contaminated by thermal water. The content of U and Ra of these spring waters is lower than that of the spring waters in Ikeda, Shimane-ken, and Misasa, Tottori-ken, where radioactive springs also issue. Finally, it is concluded that As and F will be as useful as Cl- in chemically locating a new site for a spring well in Sekigane because of the low contamination
due to human life of ground water by these elements.