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Fukushima update: Hiroshima and Nagasaki bomb experts outline health research needs after Fukushima

The Radiation Effects Research Foundation was created as a joint US-Japan research centre in 1975 with campuses in Hiroshima and Nagasaki, to study the effects of radiation among the survivors of the Hiroshima and Nagasaki bomb blasts. Roy Shore, its chief of research, and Kotaro Ozasa, chief of its epidemiology department, replied by email to my questions about the potential health effects of the Fukushima nuclear disaster, and what research might be needed to monitor these effects.

What sort of health studies could or should be done in Japan to follow any health effects of the radiation release from Fukushima, and to obtain information both of scientific value, and of importance to radiation protection? I’m thinking in terms of such studies as those laid out in the EU Agenda for Research on Chernobyl Health (ARCH) project, although the levels of radiation, and the size of the affected areas following the Fukushima accident, are of course very different.

A follow-up of the workers at the Fukushima plant is the most important in terms of its scientific and radiation-protection value, since they sustained exposure levels far greater than the general population. A second important thing is to assemble a database of harmonized information on exposure levels in different areas within the fallout area. Based on that, one can rationalize which areas may merit population studies with follow-up of individuals or other study designs. Although one cannot prejudge, it is possible that a follow up of the general population in those areas may yield limited information of scientific value owing to the generally low exposure levels, but may nevertheless be very important to provide assurance of safety and to ameliorate public health concerns. With regard to the ARCH plans, parallels to those studies might be considered several years from now, but it is too early for specific planning about most such studies (e.g., most cancers resulting from radiation arise 10 or more years after exposure).

Are studies already been planned/done?

A study of nuclear power workers has been ongoing for some years, conducted by the REA [Radiation Effects Association], including the workers at Fukushima, so their current work experience & doses will be added to that continuing study. A consortium of radiation research organizations/groups is in the initial stages of planning potential studies of the population. It is too early in the planning stage to identify what direct international scientific involvement may be needed, but it is expected that international agencies such as the IAEA, UNSCEAR and WHO will be kept fully informed and play important roles.

Which data and samples need to be taken immediately to support such studies? How important is it to collect data quickly? Is this happening?

The pollution of air, water, etc by radioactive substances in relevant sites is being recorded and would be utilized for the studies. The challenge will be to compile and evaluate the data on levels of radioactivity that are being gathered by various agencies over the range of areas involved. A high degree of cooperation among agencies and organizations will be required for this, as to our knowledge the data are scattered and uncoordinated. Behaviors of the people who were exposed to the pollution may need to be recorded to evaluate how much they were exposed to the radiation externally and internally. That would entail a widely administered questionnaire to persons in the regions to identify their whereabouts, time spent outdoors, food and water sources, etc. Obviously, it is important to obtain those data sooner rather than later, but at this point, coping with the huge effects of the earthquake and tsunami has to take precedence.

What are the radiation monitoring data needs for both radiation protection in the current situation, and for longer-term research. What aspects of current radiation monitoring need to be improved?

Since it is impossible to have measurements of external doses (i.e., vs. internally deposited radionuclides) for all individuals in a general population, it is valuable to have in place a dense set of radiation monitoring sites so as to be able to estimate exposure levels to a reasonable approximation and perhaps to have follow-up measurements of levels of cesium-137 or other radionuclides in soil samples from a systematic set of locations. Variations in exposure levels in areas between monitoring sites, variation in individual behaviors that may alter exposure levels, and inaccuracies in recall of those behaviors will all be limiting factors in the precision of individual exposure estimates.

How can such research, and research needs, be informed by experiences gained from research in both the Chernobyl accident, and other studies on the effects of low-level radiation.

The experiences of Chernobyl and others have been useful for considering countermeasures to this accident and anticipated studies. All the nuclear accidents have highlighted how important it is to develop exposure information as quickly and thoroughly (e.g., individualized) as possible, or else crude or absent exposure information may be the “Achilles heel” of the epidemiologic research activities. It is also highly desirable to have individual information on lifestyle factors (e.g., smoking), since those factors may alter health risks as much or more than the relatively low levels of radiation exposure, and such variations might create biases in the radiation risk estimates.

For full coverage of the Fukushima disaster, go to Nature’s news special.


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