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To carry out safe and steady decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS) of the Tokyo Electric Power Company (TEPCO), it is necessary to discharge of water that has been treated by the Advanced Liquid Processing System (ALPS)* and stored on the premises of the power station. Thus, in April 2021, the Government of Japan decided to discharge ALPS treated water into the sea, provided that safety was ensured and thorough countermeasures against reputational risk and misinformation were taken.

Various measures related to ALPS treated water are being taken. The Ministry of the Environment is resoponsible for conducting sea-area monitoring to confirm the status of radionuclides in the environment.

This website consolidates the monitoring results for tritium and other radionuclides conducted by the Ministry of the Environment and relevant administrative organs.

* “ALPS treated water” refers to water containing radioactive materials in the buildings of the FDNPS that has been purified of all radioactive materials other than tritium and meets safety standards. The water is significantly diluted with seawater before the dischrage. Also, before the discharge, the concentration of tritium has been lowered to a level well below the regulatory standards, as confirmed by TEPCO and Third party organization .

Benchmark tritium value and the ambient tritium concentration range

Tritium, also called “hydrogen-3,” is a radioactive isotope of hydrogen.
Because tritium is regularly formed when the radiations from outer space (cosmic radiation) collide with nitrogen and oxygen in Earth's atmosphere, it is found everywhere on Earth, not only in atmospheric water vapor, rainwater, seawater, and tap water but also in our bodies.

Benchmark values for tritium in Japan and internationally

WHO Standards for Drinking Water
10,000 Bq/L
TEPCO ALPS Treated Water Discharge Standards
1,500 Bq/L
Regulatory Standards of Tritium for safety
60,000 Bq/L

Ambient tritium concentration range (throughout Japan)

Icon of ”Seawater” Seawater
20 Bq/L or less
Icon of ”Tap Water” Tap Water
1.2 Bq/L or less
Icon of ”Rainwater (precipitation)” Rainwater (precipitation)
7.3 Bq/L or less

* This shows the range of the results of conducted from April 2015 to January 2022 among data from locations throughout Japan that are stored in Environmental Radiation Database.

Overview of results from conducted so far

Tritium in seawater

Wide-area graph of tritium in seawater
Logo of ”Arrow symbol”Zoom
Area-specific graph of tritium in seawater

Concerning tritium in seawater, the results of conducted at locations throughout Japan that are stored in the Environmental Radiation Database and the results of conducted Fukushima Prefecture by the Nuclear Regulation Authority, Fukushima Prefecture, and the Ministry of the Environment are summarized in a graph. To date, monitoring results have been sufficiently below both the national regulatory safety standards for wastewater (60,000 Bq/L) and the WHO guideline levels for tritium in drinking water (10,000 Bq/L). Such results indicate that no impact has been imposed on either humans or the environment.

[Explanation of displayed data]

Tritium in marine products and marine biota

Graph of tritium in marine products and marine biota

The results of concerning tritium (FWT) in marine products and marine biota (fish) conducted by the Fisheries Agency and the Ministry of the Environment are summarized in a graph.

[Explanation of displayed data]

  • *All of the results of analyses conducted by the Fisheries Agency are below the lower limit of detection. However, they are plotted to the respective values of limit detection for the purpose of convenience.
  • *The unit of values in this graph is “Bq/L.”
  • *The unit of the results of analyses of tritium (FWT) in marine products on the Fisheries Agency website   is “Bq/kg.” “Bq/kg” is calculated by “Bq/L × moisture content.”

Nuclides other than tritium

It had been confirmed many times ( Tokyo Electric Power Company Holdings and external organization (KAKEN) entrusted by (TEPCO) , Japan Atomic Energy Agency (JAEA) , IAEA ) before the discharge of ALPS treated water that nuclides other than tritium would be contained in the discharged ALPS treated water at concentrations below the respective regulatory standards.
Furthermore, the results of monitoring for radionuclide other than tritium conducted by the Ministry of the Environment confirm that it is within the range of past fluctuations in the surrounding sea area, with no adverse impact on humans health and the environment.

Information from respective institutions

Logo of ”Ministry of the Environment”
Ministry of the EnvironmentBOOKLET to Provide Basic Information Regarding Health Effects of Radiation

“BOOKLET to Provide Basic Information Regarding Health Effects of Radiation” summarizes the basic knowledge of radiation, scientific knowledge regarding radiation effects on health, and the efforts of related ministries and agencies.

Logo of ”Nuclear Regulation Authority”
Nuclear Regulation AuthorityReview of Implementation Plans Regarding the Handling of ALPS Treated Water

This page contains information regarding the reviews of the implementation plan of ALPS treated water discharge facility.

*Please show “ALPS treated water discharge related materials” in the web page.
Logo of ”Ministry of Foreign Affairs of Japan”
Ministry of Foreign Affairs of JapanSpecial website for ALPS treated waterThe safety of the discharge of ALPS treated water

We are relaying the information on the safety of ALPS treated water to the international society.

Logo of ”To learn about and understand ALPS treated water.”
Ministry of Economy, Trade and IndustryTo learn about and understand ALPS treated water.

Scientific evidence-based information on ALPS treated water is summarized so that it is easy to understand.
The characteristics of ALPS treated water and tritium and the safety and importance of ALPS treated water discharge are described.

Logo of ”Ministry of Economy, Trade and Industry”
Ministry of Economy, Trade and IndustryPortal site on power station decommissioning, contaminated water, treated water discharge and countermeasures against reputational risk and misinformation
Discharge of ALPS treated water

Efforts towards the discharge of ALPS treated water are shared. The information provided includes up-to-date information on discussions in inter-ministerial meetings and council meetings and on the latest efforts about safety measures, fostering understanding, and countermeasures against reputational risk.

Logo of ”International Atomic Energy Agency (IAEA)”
International Atomic Energy Agency (IAEA)IAEA Fukushima Daiichi ALPS Treated Water Discharge

Upon request by the Government of Japan, the IAEA is conducting a review using the IAEA International Safety Standards and will assess the implementation of the Government of Japan’s “Basic Policy on handling of ALPS treated water at the Tokyo Electric Power Company Holdings’ Fukushima Daiichi Nuclear Power Station” against those standards. The IAEA website linked here contains additional information about this review, a timeline of the major activities, and the reports published under this review.

Logo of ”Analysis of ALPS treated water as third-party”
Japan Atomic Energy AgencyAnalysis of ALPS treated water as third-party

The Japan Atomic Energy Agency is Japan's largest group of engineers in nuclear field and is analyzing radioactive materials contained in ALPS treated water based on its technical knowledge in a third-party capacity.
All analysis results are shown in this website.

Logo of ”Treated Water Portal Site”
Tokyo Electric Power Company HoldingsTreated Water Portal Site

The TEPCO treated water portal site introduces their efforts related to the handling of ALPS Treated water as part of the decommissioning of the Fukushima Daiichi Nuclear Power Station. It provides information on the status of storage of ALPS Treated water and the dilution and discharge equipment , as well as marine monitoring results, with charts and graphs.
Other available resources include videos and brochures on ALPS Treated water and related topics and a Q&A .