@article{oai:niigata-u.repo.nii.ac.jp:00028163, author = {橋本, 哲夫 and 樋口, 靖 and 酒井, 裕二 and 佐藤, 修 and 青木, 滋 and 外林, 武}, journal = {新潟大学積雪地域災害研究センター研究年報, 新潟大学積雪地域災害研究センター研究年報}, month = {Jan}, note = {Some spring water (18 samples), collected from the landslide area in Kanayama valley belonging to the Ura-river area, were subjected to tests to determine the tritium content to obtain some information relating to the aquifer properties. The conventional measurements of low level tritium were carried out by using liquid scintillation counting and the tritium concentrations varied from 28 to 62 pCi/l, giving the highest value comparable with that of fresh precipitation. In order to classify the aquifers, six major ion constituents (Ca^<2+>, Mg^<2+>, Na^+ + K^+, SO^<2->_4, HCO^-_3, and Cl^- ions) were used to specify each type of water into a pattern diagram (Fig. 6) and subsequently three constituents (Mg^<2+>, Ca^<2+>, and SO^<2->_4 ions) were utilized in the cluster analysis as shown in Fig. 7. The six aquifer groups were identified and the correlation between tritium and total cation concentrations was roughly recognized for each aquifer group; the higher concentrations of cation are corresponding to the lower tritium concentrations owing to the effects of radioactive decay and/or the mixing effects of old water with new precipitations. In the case of the confined waters, collected from the natural gas wells in Niigata Plain, the electrolytic tritium enhancement was applied to the tritium measurements using a Ni-multi-plate electrode because of their extremely low-level tritium concentrations. The resultant tritium concentrations are summarized in Table 1 as bracketed values in comparison with the values evaluated without enhancement in the last column. From these results, it was found that the confined water from aquifers more than 300 m below the ground surface yielded a negligible low concentration of tritium and were basically suitable as background water for the environmental tritium measurements.}, pages = {163--172}, title = {湧水・地下水のトリチウム濃度の測定 : 姫川系浦川流域および新潟地区水溶性天然ガス井からの天然水中のトリチウム濃度 (中俣三郎教授退官記念号)}, volume = {7}, year = {1986} }