Background

This guidance is for people living and working for extended periods with their families and children in those areas contaminated by the fallout from the Chernobyl accident.

Several scientific publications provide the background for this advice. Several of these relate to the 1990-91 "International Chernobyl Project". This project involved some 200 experts from 25 countries and 7 international organizations, who carried out their work under the Chairmanship of Prof. Shigematsu of the Radiation Effects Research Foundation in Hiroshima. The full documentation included a Technical Report, an Overview, A Brochure, a Broadsheet and a Contamination Map. A second major source of information is the proceedings of the IAEA/WHO/EC International Conference: One Decade after Chernobyl - summing up the consequences of the accident (held in Vienna in April 1996). Associated publications include the results of the conference, an IAEA Bulletin dedicated to the conference, and a public information brochure. The Agency's Division of Publications can provide printed copies of these on request.  The most recent source of internationally accepted information on radiological consequences of the Chernobyl accident is the UNSCEAR 2000 Report to the General Assembly on Sources and Effects of Ionizing Radiation, United Nations, New York, 2000, V.II: Effects. Annex J: Exposures and effects of the Chernobyl accident.

Salient points

The main features concerning the contamination situation may be summarised as follows:

• The most significant radiation dose to the populations of Belarus, Ukraine and parts of Russia came from radioiodine, principally the short lived radionuclide Iodine-131, in the first few weeks after the accident. This radionuclide produced high exposures to the thyroids of many members of the public, especially of children. We know that exposure to radioiodine can lead to an increase in the risk of thyroid cancer. There has been an increase in cases of childhood thyroid cancer in Belarus, Ukraine and Russia and they are almost certainly as a direct result of exposure to radioactive iodine. Since Iodine-131 has an eight-day half-life, and has now completely vanished, the group at risk of contracting thyroid cancer are young children who were drinking contaminated milk and eating foodstuffs in May and June 1986. However, there is NO increased risk of thyroid cancer to anyone moving into and living and working in these areas now.
  
• The residual low-level radiation now in the contaminated areas is dominated by the long-lived radionuclide, caesium-137 (which has a half-life of 30 years). This radionuclide is readily detectable in some foods and in soil in these areas, and can even be detected in trace amounts outside the areas. In any case state-supplied food is reportedly controlled to criteria that are more stringent than those recommended by FAO/WHO for foods moving in international trade. It is possible that some home-produced foods (mainly ‘wild’ foods - such as mushrooms, berries, and game) can exceed the levels used by the state for control, and given current economic conditions may be found on the ‘black market’. To reduce intake of caesium-137 in inhabitants of contaminated areas of Belarus, Ukraine and Russia it is advisable to boil mushrooms collected in local areas for a few minutes and to remove the obtained liquid. Nevertheless even if this food were consumed inadvertently and occasionally this would not give rise to substantial risks.
  
• In some contaminated areas there are local restrictions in force on access (particularly to forests), and warning about, for example, picking mushrooms, but there are no areas outside the exclusion zone that cannot be visited safely. People previously living in some settlements in the more highly contaminated areas have been resettled to other areas. This has been done in order that they can avoid accumulating radiation doses over their entire lifetimes. However, short visits even to these areas do not constitute a hazard.

• The doses and risks of living in the contamination zones can be estimated very roughly according to the zone of contamination as follows:

  1 Ci/km² of caesium-137 corresponds to an additional lifetime dose to someone living and working there all their life (since 2000) of 1 to 3 mSv depending on local natural conditions.  The average dose to the world population from natural background radiation is about 2.4 mSv per year. Over a lifetime the dose from natural background radiation corresponds to about 2.4 ´70 = 168 mSv. Thus spending the rest of one’s life living in the zone with contamination of 1 Ci/km² represents an increase of 1/168 to 3/168 or 0.6% to 1.8% in one’s radiation dose (excluding any doses received during medical practices).

  Associated with this increase in the lifetime dose, there is a statistical increase in the risk of fatal cancer. This amounts to a chance of less than 1 in 10 000 of death from cancer due to Chernobyl to someone spending their entire life in this same zone. Since, at least in western countries, 1 in 5 deaths are due to cancer, this corresponds to a statistical increase of less than 0.1 % over the norm.

  For people living in these areas for shorter but extended periods of time, the doses and risks would be correspondingly less. And for people living in the zones of higher contamination the doses and risks are correspondingly higher (e.g. for someone spending their entire life in an area with 15 Ci/km² of contamination would correspond to a statistical increase in the risk of death from cancer of less than 0.1% x 15 = 1.5 % over the norm. This estimate does not include doses that anyone living in these areas received in previous years but are solely to estimate risks of living in these areas now and in the future.

  It should be noted that neither Kiev nor Minsk lie within any of these zones, and living in either of these cities means that doses and risks are considerably less than those stated in the preceding two paragraphs. Indeed the additional radiation doses are much smaller than the differences in the natural background doses between some parts of Europe, e.g. between the U.K. and Finland, and even the northern part of Italy compared with the south.

  The 30-km "exclusion" zone remains `out-of-bounds' to the public, although official visits can be arranged and suitable radiation protection precautions will and should be carried out.

Summary

In summary, the recommendations that could be considered are as follows:

• Inhabitants and workers in Kiev and Minsk need take no special precautions about radiation exposure or commercially available foodstuffs, although some ‘wild’ foods found on the ‘black market’ can sometimes exceed the state imposed restrictions.
• Special radiation protection conditions pertain to visits to the 30-km exclusion zone.
• In some of the contaminated areas, special advice may be available locally that will vary from district to district. Nevertheless, there is certainly no significant hazard for short casual or tourist visits.
• Local advice and results of site monitoring are advisable for entrepreneurs and companies wishing to set up joint ventures and/or businesses in the contaminated areas.

While this advice is given in good faith, neither the Agency’s Member States nor its Secretariat can be held legally responsible for its accuracy or applicability.