Information on treated water and decommissioning
（2026）
ＱWhere can I find measurement results for tritium in the environment?
ＡThe Japanese government, Fukushima Prefecture, and Tokyo Electric Power Company (TEPCO) have been monitoring tritium concentrations in river water and seawater. The monitoring results can be accessed on the “Environmental Radiation Monitoring Data Search site about the Great East Japan Earthquake.”
Fig. 1. Environmental Radiation Monitoring Data Search site about the Great East Japan Earthquake (1)
The “Environmental Radiation Monitoring Data Search site about the Great East Japan Earthquake” is an open database site that compiles concentrations of radioactive cesium and other radionuclides in environmental samples, such as water and soil, and food in Fukushima Prefecture and the surrounding areas, as well as air dose rates monitored by the Japanese government, municipalities, Tokyo Electric Power Company, and research institutions.
The tritium concentration in seawater near the nuclear power station is periodically measured by the Japanese government, Fukushima Prefecture, and Tokyo Electric Power Company. On the top page of the site, click “SEA WATER,” set [Term] in the search conditions, select H-3 (tritium) from the [Nuclide] drop-down menu, check [Middle classification] and [Measurement Items], and click “≪ Render Map.”
Fig. 2. Environmental Radiation Monitoring Data Search site about the Great East Japan Earthquake (2)
To check detailed measurement values and temporal changes, select the point you want to examine and click the graph icon on the left to display the graph and check the measured values.
Fig. 3. Environmental Radiation Monitoring Data Search site about the Great East Japan Earthquake (3)
Tritium concentrations in river water are monitored by Fukushima Prefecture. You can check the concentrations by clicking “RIVER WATER” on the top page and following the same procedure.