Tritium concentration table of groundwater recharge for groundwater dating in Japan

Groundwater dating with tritium is an important substantiation of groundwater research. The application of tritium measurement can be expected to be a new research industry. The precipitation tritium data by monthly sampling have been observed for 56 years in Tokyo area, and it has been shown as an open access database in the web site of National Institute of Radiological Sciences. The tritium concentration of groundwater recharge should be necessary for groundwater dating. It was estimated from the annual maximum and minimum concentrations in the database by using the theoretical equation and area constants proposed in our previous paper. This paper presents the tritium concentration table of groundwater recharge at four sampling sites widely dispersed across Japan, i.e., Sapporo, Niigata, Tokyo, and Matsuyama. The tritium concentration table with logical significance should be useful for hydrological study. (author)