Tritium Concentration in Natural Spring Water Collected at Hirosaki, Japan

抄録

In order to understand the regional property of tritium concentration in natural water at Hirosaki City, Aomori Prefecture Japan, natural spring water samples were collected from 15 sites in 2016 and tritium concentration was measured by low-level tritium counting procedure using a commercially available solid polymer electrolyte (SPE) tritium enrichment system. The limit of detection of this procedure was approximately 0.06 Bq/L. Findings showed tritium concentrations in natural spring water samples ranged from 0.30 to 0.55 Bq/L with mean value of 0.44±0.08 Bq/L. These results were within the range of reported concentrations in rain and surface and shallow groundwater in Japan including other places of Aomori Prefecture. The presently obtained data could be considered as the background level of the Hirosaki area. The annual effective dose would be negligibly small compared with the annual effective dose limit of 1 mSv, if the committed effective dose equivalent from drinking water to residents was calculated using the highest tritium concentration data.