On 16 May 2011 the European Commission hosted a meeting of experts from the Environment Laboratories (Monaco) of the International Atomic Energy Agency, the Institut de Radioprotection et Sûreté Nucléaire, the Centre National de la Recherche Scientifique and Mercator Ocean to discuss the potential contamination of fish and other marine products in the Pacific following the Fukushima accident.

Samples of fish caught within the Japanese Exclusive Economic Zone are monitored by the Japanese authorities. Levels of radioactive caesium and iodine in most samples of one particular fish, the Japanese sandlance, are above the limit for safe human consumption and therefore these fish are not put on the market. No contamination above this limit has been measured in other species. As stipulated by Commission regulations[1] introduced after the accident, 20% of imports from the most affected prefectures and 10% from the rest of Japan are also checked within the EU. So far no contamination has been detected.

Mathematical simulations by the SIROCCO software from the Centre National de la Recherche Scientifique using boundary conditions derived from the Global Monitoring for Environment and Security's MyOcean project indicate that radioactive seawater leaving the Japanese Exclusive Economic Zone are presently restricted to the surface layers of a plume. Internationally-recognised correlations suggest that, within that plume, concentrations could reach levels that could cause contamination in living organisms to rise above safe levels. Furthermore certain migratory fish, particularly tuna and swordfish, could feed on contaminated fish inside Japanese waters, be caught outside these waters and landed outside Japan.

The risk of contamination of fish from the Pacific outside the Japanese Exclusive Economic Zone being above safe limits for human consumption is low but not zero. Furthermore until all the reactors achieve cold shutdown towards the end of the year, the risk of further release cannot be ruled out. The experts recommended that samples of imports of pelagic fish from the Pacific continue to be checked as recommended by the Commission on 16 April 2011.

These conclusions were drawn from calculations validated by measurements made within 30 km of the Japanese coast. Measurements further from the coast, some of which are already planned, will allow a better validation of the calculations and more confidence in the findings.

The participants of the meeting agreed to deepen their future collaboration on this issue in order to provide a more integrated view of the impact of the Fukushima accident on the marine environment and the possible risk.

A strengthened dialogue with Japanese agencies will also be sought. Nearly all the information used to understand the risk comes from these agencies and ministries. They have been admirably quick in releasing the results of measurements and posting them on the internet. However a stronger partnership can improve the efficiency of the risk assessment. Better knowledge of other parameters, such as river outputs, will improve the accuracy of the ocean circulation modelling. Information on measurement protocols will help with the assessment of confidence limits. Digital data transfer can reduce the time spent in data processing.

A follow-up meeting is planned for September when more measurements and simulations will be available. Participation from other experts, from both within and outside the EU, will be encouraged.

[1] Commission Implementing regulation (EU) No 297/2011 of 25 March 2011 as amended by Commission Implementing Regulation No 351/22011