Assessing the Chernobyl Consequences

During the past decade, many international activities have helped assess the Chernobyl accident's consequences. These activities can be divided into two periods: those carried out before the 1990 International Chernobyl Project which gave a fuller account of the accident, and those activities which follow up the Project to the time of the International Chernobyl Conference April 1996.

1986-89: The Initial Picture - Piecing Together the Facts

August 1986: The Post-Accident Review Meeting. A widely attended international gathering was organized by the IAEA a few months after the accident: the "Post-Accident Review Meeting". The outcome was reported on by the then recently created International Nuclear Safety Advisory Group, INSAG.1

The INSAG report examined the causes of the accident and presented the preliminary Soviet assessment of the amount of radioactive materials released from the damaged reactor. It also contained a limited but significant early account of the radiological consequences:

Some calculations on the potential long-term health effects were also made and the chances of epidemiological detection of these effects were judged to be limited: only in the cohorts with substantially high doses could some effects possibly be discovered, e.g. benign and malignant thyroid neoplasms.

May 1988: The Kiev Conference. Two years later, the international scientific community had the second opportunity to review the radiological consequences during the International Scientific Conference on the Medical Aspects of the Accident at the Chernobyl Nuclear Power Plant held by the Soviet authorities in co-operation with the IAEA in Kiev in May 1988. (An unedited version of the Conference proceedings was issued by the IAEA as an unpriced publication and a report summarizing the information also was published.)2

Information presented at the Conference covered various topics:

December 1988: Global Assessment by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). UNSCEAR did a thorough assessment of the impact outside the USSR. In its 1988 report to the UN General Assembly, UNSCEAR estimated that:

May 1989: The Extent of Consequences Crystallizes - The IAEA "Ad Hoc Meeting". Three years after the accident, scientists obtained a more comprehensive insight into the magnitude of the accident's consequences at an informal ad hoc meeting which was organized by the IAEA Secretariat in May 1989 at the time of the 38th session of UNSCEAR. It was attended by over 100 scientists from 20 countries and reported at a subsequent symposium on recovery operations after accidents3. The information provided by Soviet experts attending the meeting gave a more detailed account of the long-term situation:

1990-91: A Fuller Account - The International Chernobyl Project

March 1990 - May 1991: Expert assessments on site - More facts emerge. In October 1989, the USSR formally requested the IAEA to co-ordinate "an international experts' assessment" of the concept which the USSR had evolved to enable the population to live safely in areas affected by radioactive contamination following the Chernobyl accident, and an evaluation of the effectiveness of the steps taken in these areas to safeguard the health of the population.

As a result, the International Chernobyl Project (ICP) was launched in early 1990.4 It focused on four key issues of concern to the population and policy makers: the extent of the existing contamination in the inhabited areas; the projected radiation exposure of the population; the current and potential health effects; and the adequacy of measures being taken at the time of the Project to protect the public. Conclusions and recommendations were approved by the ICP International Advisory Committee on 22 March 1991 and presented for scrutiny to an international conference in Vienna 21-24 May 1991. They were published by the IAEA and can be summarized as follows:

The ICP also recommended a number of follow-up actions including continuing epidemiological evaluations and fostering health care, concentrating on "selected high risk populations".

1991-96: Follow-up Co-operative Studies - Toward Clearer Perspectives

Many international initiatives followed the International Chernobyl Project, including those highlighted here.

Follow-up initiatives by the IAEA. An agricultural countermeasures project was sponsored by FAO and IAEA 5 and a new environmental assessment was organized by IAEA and supported by the Institut de protection et de sûreté nucléaire (IPSN, France) 6.

The WHO International Programme on the Health Effects of the Chernobyl Accident (IPHECA). The results of the IPHECA project were recently published and discussed at the WHO International Conference on the Health Consequences of the Chernobyl and other Radiological Accidents, held in Geneva, 20-23 November 1995. IPHECA generally confirmed the conclusions of the ICP and provided additional information on the increase in child thyroid cancer incidence foreseen by the ICP.

The IPHECA conclusions can be summarized as follows:

Projects supported by the European Commission (EC). The EC supported many scientific research projects on Chernobyl's consequences. The results were summarized at the First International Conference of the European Union, Belarus, the Russian Federation and the Ukraine on the Consequences of the Chernobyl Accident, held in Minsk, on 18-22 March 1996. The projects produced valuable information that can be used for future emergency planning, dose assessment and environmental remediation, as well as in the treatment of highly exposed individuals and in screening for thyroid cancer in children.

Other initiatives. These include several UNESCO supported studies, mainly on psychological consequences; special reports from UNSCEAR and the Nuclear Energy Agency of the OECD; and individual studies in the affected States and in other countries, e.g. a comprehensive monitoring of the affected people carried out by Germany, an extensive study sponsored by Japan s Sasakawa foundation, a major USA project and a large Cuban assessment on the intake of caesium-137, covering about 15,000 children.

April 1996: the International Conference on One Decade After Chernobyl - Summing up the Accident's Consequences. The main organizations involved in assessing the Chernobyl accident's consequences, namely the IAEA, WHO and EC, united their efforts in co-sponsoring the recent Chernobyl Conference. They organized the event in co-operation with the UN itself (through its Department of Humanitarian Affairs), UNESCO, UNSCEAR, FAO and the Nuclear Energy Agency of OECD. The Chernobyl Conference was attended by 845 scientists from 71 countries and 20 organizations and covered by 280 journalists. It was presided over by Germany s Federal Minister for the Environment, Nature Conservation and Nuclear Safety and attended by high-level officials and members of government, including the President of Belarus, the Prime Minister of Ukraine, and the Russian Federation's Minister for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters, as well as by France's Minister for the Environment. Three national reports, 4 addresses by intergovernmental organizations, 11 keynote presentations, 8 background papers, 181 detailed poster papers and 12 technical exhibits provided the basis for this summing up of the Chernobyl accident's consequences.

1 International Nuclear Safety Advisory Group, Summary Report on the Post-Accident Review Meeting on the Chernobyl Accident, Safety Series No. 75-INSAG-1; IAEA; Vienna (1986).

2 See Proceedings of the All-Union Conference on the Medical Aspects of the Chernobyl Accident; IAEA-TECDOC 516, and Konstantinov, L.V. and González, A.J.; "The Radiological Consequences of the Chernobyl Accident"; Nuclear Safety; Vol. 30, No. 1 (January-March 1989).

3 González, A.J.; "Recovery operations after the Chernobyl Accident: The intervention criteria of the USSR's National Commission on Radiation Protection"; IAEA-SM-316/57; in the Proceedings of International Symposium on Recovery Operations in the Event on a Nuclear Accident or Radiological Emergency; IAEA-SM-316/57; page 313.

4 The ICP was sponsored by the European Commission, the Food and Agriculture Organization of the United Nations, the International Labour Organisation, the World Health Organization, the World Meteorological Organization, the IAEA, and UNSCEAR. An independent "International Advisory Committee" of 19 members was set up under the chairmanship of Dr. Itsuzo Shigematsu, the Director of the Radiation Effects Research Foundation in Hiroshima, which, ever since 1950, has monitored and analysed the health of atomic bomb survivors in Japan, the largest population ever exposed to high doses of radiation. The other scientists on the Committee came from ten countries and five international organizations. The expertise encompassed, among other disciplines, medicine, radiopathology, radiation protection, radioepidemiology and psychology. The most active phase of the project ran from May 1990 until the end of that year. About 200 experts from 23 countries and 7 international organizations participated, and 50 scientific missions visited the USSR. Laboratories in several countries, including Austria, France and the USA, helped to analyse and evaluate collected material.

5 The "Prussian Blue (PB) Project" aimed to reduce contamination in milk and meat using a technique involving the use of the PB chemical compound in ruminants' foodstuffs. It was mainly funded by the IAEA and Norway whose specialists developed the technique. With time this project would prove to be the most cost effective of all post-ICP follow up projects. A US $50,000 annual investment by Belarus saved US $30m of lost milk/meat production annually.

6 Following a specific request of Belarus at the 1994 IAEA General Conference, the IAEA engaged in a mainly environmental project on "prospects for the contaminated area". The project has been financed mostly by IPSN, which was heavily involved in its technical implementation together with scientists of the affected regions. Some conclusions arose that extend beyond the general conclusions of the ICP to cover the general environment. Referring to the forested biocoenosis - the environmental system that had reportedly suffered most from the Chernobyl accident - the project concluded that the radioactive contamination was not on a massive scale and affected mainly pine forests: the death of the pine plantations, although severe in the immediate vicinity of the plant, amounted to less than 0.5% of the forested area of the exclusion zone.