Dose Rates for Population Near Semipalatinsk
Complex Examination of Semipalatinsk Test Site Region Population by Advanced Dosimetry Methods
Tech Area / Field
- ENV-EHS/Environmental Health and Safety/Environment
8 Project completed
Senior Project Manager
National Nuclear Center of the Republic of Kazakstan / Institute of Nuclear Physics, Kazakstan, Almaty
- CEA / IPSN (Institut de Protection et Sûreté Nucléaire), France, Fontenay aux Roses\nNational Radiological Protection Board, UK, Chilton\nForschungszentrum Jülich, Germany, Jülich\nBaylor College of Medicine, USA, TX, Houston
Project summaryThe UN Secretary General stated in his report for 53d UN General Assembly that many-year intensive nuclear weapon testing conducted at the Semipalatinsk Test Site caused immense damage to the ecology and population health of the region. The UN appealed to the world community for every possible assistance to Kazakhstan in solving the most vital problem of present and future generations that is associated with surmounting the nuclear test effects.
One of the major tasks is to perform a reliable assessment of population dose loads in settlements near the Test Site. This is necessary in order to develop scientifically-founded measures of population and environment rehabilitation as well as to predict the effects of possible future nuclear accidents. Currently available data on population doses is rather contradictory. Some authors consider exposure doses of nuclear test witnesses to be several Gy, meanwhile others assert that doses received by population corresponded to a few tens of mGy. The main reason of this contradiction is imperfection of methods used for determination of the integral dose and lack of data on radiation monitoring that is necessary for calculation of the integral dose.
A new technique of retrospective dose assessment using analysis of EPR-radiation signal in tooth enamel is being rapidly developed for several last years. IAEA and WHO consider it now as a base one for assessment of effects caused by radiation. However, in Kazakhstan this technique has not yet been used due to the lack of up-to-date EPR equipment. In 1997, considering the urgency and importance of such investigations, the Government of Japan donated to the Institute of Nuclear Physic (INP) a set of very expensive EPR equipment and software that now allows performing the EPR analysis on the up-to-date level. In the three years INP gained considerable experience in this field and proved it in the course of the “Intercomparison 2” International Experiment organized in November 1998 – May 1999 by IAEA for mastering the technique of small dose determination using EPR dosimetry. In June 1999 the EPR Laboratory of the Institute was certified by Kazakhstan State Standard Agency. Thus, now there are all necessary prerequisites for determination of a dose load of the population both in region STS, and in other regions of Kazakhstan, with application of a EPR- dosimetry method .
The technique EPR gives the rather reliable information on an integrated doze of external irradiation. Unfortunately, it does not completely take into account inner irradiation at radionuclides entry inwards organism. Therefore for obtaining of the more complete information it is planned to add EPR data by results of two versions cytogenetic biodosimetry (G- banding and FISH) in the samples of blood of the persons - donors of teeth. These data objectively characterize real consequences, caused by influence of all adverse factors, stipulated by a close arrangement of the of nuclear test range.
Besides, data obtained using these methods will be compared with data available in archives and data obtained for the same persons using traditional radiometry methods: whole body counter, radiochemistry and spectrometry of the environment and food samples.
Thus, effects of external and internal exposure as well as their real consequences will be taken into account to a sufficiently high degree.
It is necessary to note, that such a comprehensive approach with simultaneous application of three essentially different methods of modern retrospective dosimetry to the same persons was not applied yet in Kazakhstan, though only by such a way it is possible to receive a really objective information, which can be used in the future for the persified purposes.
The objective of the present Project is to perform a selective examination of inhabitants of Dolon, Mostik and Sarzhal villages that mostly suffered due to radiation exposure during the Test site operation, and of a “clean” control village with the same climatic conditions using up-to-date EPR and biodosimetry methods and to compare data obtained with archival materials available on inpidual doses and with values calculated using the whole body counter and radiometry of environmental areas and food samples.
It is necessary to take into consideration, that for EPR-dosimetry it is desirable to use teeth with enough of an enamel, but, certainly, they can be extracted only under the medical indications. Thus, the problem of deriving of a plenty of teeth for EPR- researches is enough serious.
On preliminary estimations it is supposed to receive not less than 30 - 50 samples of teeth in each from four selected villages. At all persons - donors of teeth samples of blood for the analysis of chromosome will be taken, and the inspections on whole body counter (WBC) are conducted.
During the final Project stages it is envisaged to estimate a correlation between the reconstructed inpidual dose and
· the radioactive contamination level of the territory,
· duration of the examined person living on this territory,
· the frequency of chromosomal aberrations,
· archival data.
Thus, the planned work includes collection of samples taken in the STS region, their preparation, obtaining the experimental data using a set of up-to-date techniques, equipment, and software for data processing, analysis and comparison of the obtained results as well as a presentation of them as a computer data base.
1. EPR data on exposure doses of Dolon, Mostik and Sarzhal inhabitants, who are assumed on archival materials to receive the highest inpidual doses as well as of the other inhabitants of these settlements and the control village – for different age categories.
2. Data on different chromosomal aberrations types in blood samples of the same persons and population groups.
3. Data on radionuclides content in bodies of some persons examined under items 1, 2.
4. Data of radiochemical and gamma spectral analysis of the environment and food samples on content of the most dangerous radionuclides.
5. Estimation of collective dose value and recommendations on measures to be taken to population and environment rehabilitate that will be developed on a base of analysis and generalization of data obtained.
6. Computer data base on the results of population examination.
Data obtained will also greatly contribute to revealing the real effects of possible future nuclear accidents as the information obtained in the course of the Project implementation will serve as a basis for development of a mathematical model describing the distribution of inpidual doses received by population under real nuclear accident conditions.
The Project meets the ISTC goals as it provides peaceful occupation for more than 62% of former weapon scientists and engineers. The Project topic is within the terms of humane recommendations of resolutions accepted during 52nd and 53d UN General Assemblies concerning the health protection of people suffered from nuclear tests conducted in the Republic of Kazakhstan. The Project implementation will contribute to preservation of physical and genetic health of the present and future generations living at the STS region and to the objective prediction of effects that might be possibly caused by potential future nuclear accidents.
Participants of the Project have an experience of working with ISTC on ESR dosimetry and radionuclides contains determining in SNTS soils in the frame of K-053 Project.
The role of foreign collaborators is to ensure the reliability and validity of information obtained under the Project as well as the completeness and impartiality of results published. It will be fulfilled through control measurements and participation in interpretation of experimental data under joint discussions of results obtained using different methods.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.