Japanese Data on Marine Samples Near Fukushima Reliable, IAEA Report Concludes

“Over 98% of the results were not significantly different from each other, which means the Japanese laboratories involved in the programme demonstrate a high level of consistency amongst themselves and with laboratories in other countries and the IAEA,” said Iolanda Osvath, Head of the IAEA’s Radiometrics Laboratory.

The IAEA has worked with the Japanese laboratories since 2014, following a request by the Japanese Government to assist it in ensuring that its sea area monitoring around Fukushima Daiichi maintains a high quality, and is comprehensive, credible and transparent. The project is a follow-up activity to recommendations made on marine monitoring in a report by the IAEA in 2013 related to the decommissioning of the Fukushima Daiichi Nuclear Power Station, which reviewed Japan's efforts to plan and implement the decommissioning of the plant.The project has now been extended for another four years. The next steps will build on the already completed work and involve more interlaboratory comparisons and proficiency tests.

Recent results

The most recent interlaboratory comparison performed late last year involved seawater samples and six batches of fresh fish caught near the Fukushima Daiichi Nuclear Power Plant. The seawater samples were analysed for tritium (hydrogen-3), strontium-90, caesium-134 and caesium-137 by the Japan Chemical Analysis Center (JCAC), the Geo Science Laboratory (GSL), Japan, KANSO Co., LTD., Japan and the IAEA Environment Laboratories. The fish samples were analysed for caesium-134 and caesium-137 by the Marine Ecology Research Institute (MERI) in Onjuku, Japan, JCAC, the Japan Frozen Foods Inspection Corporation (JFFIC) and the IAEA Environment Laboratories.

In the proficiency test exercises, the IAEA prepares test samples of low radioactivity seawater and requires the participating laboratories to measure its level of radioactivity. The amount of radioactivity in these so-called ‘spiked samples’ is not known to the participating laboratories, who report their methods and results to the IAEA. Over 50 laboratories worldwide, including 17 Japanese laboratories, participated in these exercises. Proficiency test results published so far for this project are available on the IAEA website. 

The IAEA runs similar exercises for analytical laboratories worldwide in order to improve and maintain high quality analytical capabilities.