2018 Volume 67 Issue 1 Pages 21-33
After the Fukushima Dai-ichi Nuclear Power Plant accident, the Ministry of Health, Labour and Welfare set the provisional regulation values for radioactive materials in foods by adopting Indices for Food and Beverage Intake Restriction. The indices were established based on 5 mSv of effective dose and 50 mSv of committed equivalent dose to the thyroid in compliance with the recommendations of the International Commission on Radiological Protection and others. On April 1, 2012, the present standard limits were put in force for the exiting exposure situations. The standard limits were intended not to exceed 1 mSv/year from food intake. One milli-Sievert per year of maximum permitted level conforms with the intervention exemption level (reference level) adopted by the Codex Alimentarius Commission. The provisional regulation values and the present standard limits of Japan are lower than the derived intervention levels of the U.S., the EU and Codex.
Immediately after the monitoring of foods began, public concern was raised since many samples of leafy vegetables and raw milk were found to be above the provisional regulation values. Thus, several public health protection measures were taken to decrease the concentrations of radioactive materials in foods by the Ministry of Agriculture, Forestry and Fisheries, the local governments and the farmers, such as feeding livestock with safe food and the application of potassium fertilizer. Due to these measures, almost all of the marketed foods in Japan are below the standard limits and concentrations of radioactive cesium are sufficiently low at this moment. Results of dose estimation with the monitoring data and total diet studies also show committed effective doses from food are well below the maximum permissible level; thus, it can be concluded that the measures taken by Japan after the Fukushima accident were reasonably successful.
However, there are still some foods found with radiocesium concentrations above the standard limit like wild mushrooms, wild animal meat, wild vegetables, freshwater fish, and some saltwater fish whose feeding or cultivation management are difficult to control. Thus, monitoring of those foods should be continued.