Preliminary dose estimation from the nuclear accident after the 2011 Great East Japan Earthquake and Tsunami
The earthquake and tsunami in Japan on 11 March 2011 led to releases of radioactive material into the environment from the Tokyo Electric Power Company’s Fukushima Daiichi nuclear power station. This report describes an initial estimate of radiation doses resulting from this accident to characteristic members of the public in populations around the world.
In line with its defined role in radiation emergency response among international organizations, the World Health Organization (WHO) is responsible for public health risk assessment and response. Therefore soon after the accident, WHO initiated a health risk assessment to support the identification of needs and priorities for public health action and to inform Member States and the public.
The aim of the health risk assessment is to estimate at global level the potential health consequences of human exposure to radiation during the first year after the Fukushima Daiichi nuclear power plant accident. The assessment covers infants, children and adults living in the Fukushima prefecture, nearby prefectures, the rest of Japan, neighbouring countries, and the rest of the world.
Because the health risk assessment requires an estimation of radiation doses delivered to the population, WHO established an International Expert Panel to make an initial evaluation of radiation exposure of people both inside Japan and beyond, as a result of the accident. The panel members were required to sign a declaration of interests, and no conflicts of interest were identified for any of them. The dose assessment was conducted by more than 30 experts who served in their individual capacities, either participating in the Expert Panel meetings or providing technical contributions from their respective institutions. All participating experts were selected on the basis of their scientific competence and experience.
Additionally, the panel included representatives of the International Atomic Energy Agency, the Food and Agriculture Organization of the United Nations and WHO in view of the relevance of their areas of expertise. The United Nations Scientific Committee on the Effects of Atomic Radiation, which has initiated a two-year assessment of the exposure levels and effects that will be submitted to the United Nations General Assembly in 2013, participated as an observer in the WHO assessments to ensure compatible approaches and data sources for the two United Nations activities. The Government of Japan also designated representatives to attend the meetings of the panel as observers.
Three panel meetings were convened in June, September and October 2011.
This report provides data on effective doses and equivalent doses to the thyroid in members of the public resulting from exposure over the first year after the accident for different regions of the world, with greater spatial detail for the estimated doses inside Japan and, in particular, in the Fukushima prefecture.