Tritium Concentration in Ukedo River through Namie Town, Fukushima Prefecture, Japan

Abstract

Discharge of treated water including tritium from the Fukushima Daiichi Nuclear Power Plant (FDNPP) had begun since August 2023. To understand the regional background level for public concern of tritium, river water samples were collected at upstream and downstream at Ukedo River located through Namie Town, and measured tritium concentration. As the results, tritium concentration at upstream during April 2021 to April 2024 ranged from 0.27 to 0.52 Bq/L, and the average concentration of 2022-2023 was 0.38±0.06 Bq/L. Those of downstream during October 2021 to April 2024 ranged from 0.26 to 0.59 Bq/L, and the average concentration of 2022-2023 was 0.39±0.10 Bq/L. There was no clear seasonal variation at both sites. It has been reported that the range of tritium concentrations in precipitation in the Tsushima area from October 2012 to December 2021¹⁾. Our result of average tritium concentration in Ukedo river water was comparable to the those of average tritium concentration in precipitation at upstream area.