Analysis of matter origin on river and ground waters using environmental isotopes

Tritium is a radioisotope element and decays under emission of radiation. It has 12.3 years of half life period and is formed by collision between cosmic ray and nitrogen atom in air to be contained into rain water. Then, water penetrated into underground had less concentration of tritium as more times passed because of no adding new tritium into the groundwater. Some researches to estimate an age of ground water from concentration of tritium in it were carried out. And, another important environmental isotope an well as hydrogen is oxygen, of which ratio of 16 and 18 in atomic weight is measured. Here were shown on some research examples to estimate origin and behavior of matters using environmental isotopes under researching now. They are at their establishing steps on a number of river and ground waters to elucidate their more effective analytical method. (G.K.)