[en] The most significant impact of the Chernobyl accident of 26 April 1986 is the increased incidence of thyroid cancer among Belarusians, Russians, and Ukrainians who were exposed as children to radioiodines in fallout resulting from atmospheric releases. The US National Cancer Institute (NCI), in cooperation with the ministries of health of Belarus and Ukraine, is involved in epidemiological studies of thyroid diseases related to the accident. Individual thyroid doses, as well as uncertainties, have been estimated for the members of the cohort studies (approximately 13,000 Ukrainians and 12,000 Belarusians). The cohort subjects, who were selected from the large group of children whose thyroids were monitored for gamma radiation within a few weeks after the accident, provided personal information on their residence history and dietary habits during interviews. Thyroid dose estimates range from 1 mGy to more than 20 Gy. The uncertainties are found to be approximately log normally distributed, with geometric standard deviations ranging from 1.6 to 5.0. The medians of the geometric standard deviations are 1.7 for the Ukrainian subjects and 2.1 for the Belarusian subjects. The major sources of uncertainty in the thyroid dose estimates are found to be those related to the thyroid mass of the subject and to the estimation of the thyroidal content of ¹³¹I at the time of thyroid monitoring. (author)

[en] Starting from May 1986 instrumental control of internal exposure is being carried out in Belarus using different equipment. In earlier, iodine period, the basic aim of the control was a mass screening of the population for defining of iodine content in thyroid. After the iodine period attention of the radiological control was focused on monitoring of caesium radionuclides content in human bodies of the inhabitants of radioactively contaminated territories. Goals of the control were changing, depending on the time that passed since the day of the accident. Nowadays the National Commission of Belarus recognizes entering of the, Republic into rehabilitation period of the accident of the Chernobyl Nuclear Power Plant. Developed Conception of Protection Measures for the rehabilitation period for the population living at the territories affected by the radioactive contamination in the result of the Chernobyl catastrophe

[en] Full text: Following the Chernobyl accident, the studies of levels and features of external and internal exposure doses for the population affected by the radioactive contamination being conducted in Belarus. The report presents results of the consideration of different pathways to the population exposure. A model has been shown to account for external exposure of the public from radioactive fallout. To estimate internal exposure, the results of wide-scale whole-body-counter measurements made in Belarus since the accident have been used. These data allowed to validate parameters of the empirical model for the internal dose assessment. The annual and collective doses from radioactive contamination in Belarus have been assessed. (author)

No abstract available

[en] Short communication

[en] In 2000, IRSN and GRS initiated a support for collecting, securing and validating of existing data in the field of Chernobyl accident consequences and establishing a database including a detailed documentation in order to make available all reliable and objective information for decision makers, for planning of actions, for information of the public and for further scientific work. Three projects as a part of French/German Initiative (FGI) for humanitarian and technical assistance in favour of the Ukraine, Belarus and Russia have been established. The authors represent sub-project 3.9.1, which objectives are as follows: (i) develop and replenish the database for the Radiological-Hygienic Passports (RHP) and perform additional investigation of the target settlements in Belarus where comprehensive information has not been acquired yet, (ii) establish conditions and communication infrastructure for database availability, (iii) provide data analysis involving data on individual effective dose monitoring and results of countermeasures applied, and (iii) formulate the wider recommendations for the target settlements located in contaminated areas, concerning radiation, health, sanitary and social protection, countermeasures, industrial infrastructure development and reviving the local economy. During implementation of the project, 96 settlements with total population of 25 thousand were investigated and their RHPs were compiled. Every RHP consisted of 13 separate forms grouped under three principal headings: Statistics (societal and demographic structure of population, housing, land used and predominant soil type); Economical infrastructure and public utilities (farms, industries, schools, hospitals, shops, service, etc.); Radiological data and doses (total area subdivided vs. level of contamination, Cs-137 content in human body, contamination of agricultural products, contamination of households, annual effective dose). Every RHP was concluded with proposals as to the countermeasures recommended and was incorporated in the database developed. It addresses the above settlements and all other critical locations, assists for evaluation of radioecological conditions and ranking of contaminated settlements, files data on these settlements, recommends and evaluates protection measures, and provides decision-makers with a risk-based remedial planning and a feasibility assessment of recommended measures based on a cost-benefit analysis. To support a decision protocol, the database, in addition to informational block, contains also a simulation block comprised by the following models: (A) contaminant transfer to basic forage resources and food; (B) exposure and risk assessment and prediction; and (C) cost and efficiency analysis based on data of available countermeasures. This study is funded by FGI Programme. (author)

[en] The structural and chemical surface transformation of basic kimberlite-forming minerals (calcite, olivine, serpentine) under the contact with natural and waste mineralized water and products of electrochemical treatment of the water are studied using X-ray photoelectronic spectroscopy, scanning electron microscopy and X-ray spectral micro-analysis, and atomic force microscopy. It is found that contact with kimberlite extract and recycling water induces chemical modification of calcite surface, which consists in adsorption of hydrocarbon impurities, and chlorine- and silica-bearing compounds, majority of which are removed during interaction with the product of electrochemical treatment of recycling water. The change in the structural and chemical surface properties of rock-forming silicates, aside from adsorption–desorption of organic compound, is also connected with the distortion of nano-size layer structure after leaching of Mg, Fe and Si, and with the carbonatization of the surface.

[en] In this paper main regularities of the long-term exposure of the population of former USSR after the Chernobyl accident are described. Influence of some natural, human and social factors on the forming of external and internal dose in the rural and urban population was studied in the most contaminated regions of Belarus, Russia and Ukraine during 1986-1994. Radioecological processes of I, Cs and Sr nuclides migration in biosphere influencing the processes of population dose formation are considered. The model of their intake in human body was developed and validated by large-scaled measurements of the human body content. The model of external exposure of different population groups was developed and confirmed by the series of individual external dose measurements with thermoluminescent dosemeters. General dosimetric characteristics of the population exposure are given along with some samples of accumulated external and internal effective doses in inhabitants of contaminated areas in 1986-1995. Forecast of the external and internal population effective dose is given for the period of 70 years after the accident

[en] The investigation of influence exerted by ultrasound processing on recovery of zirconium and rare earth elements in pregnant solution of acid leaching of eudialyte concentrate is described. The methods of X-ray photoelectron spectroscopy and analytical scanning electron microscopy are used to study structural, chemical and morphological characteristics as well as elemental composition of minerals in eudialyte concentrate before and after acid leaching.

[en] Full text: The U.S. National Cancer Institute (NCI), in cooperation with the Ministry of Health of Belarus is involved in epidemiological studies of thyroid diseases in children presumably related to the Chernobyl accident. Within the framework of this study, individual thyroid absorbed doses, as well as uncertainties, have been estimated for all members of the cohort (11,918), who were selected from the large group of children aged 0 to 18 whose thyroids were monitored for gamma radiation within a few weeks after the accident. Information on the residence history and dietary habits of each cohort member was obtained during personal interviews. The methodology used to estimate the thyroid absorbed doses resulting from intakes of I 131 by the Belarussian cohort subjects is described. The model of thyroid dose estimation is run in two modes: deterministic and stochastic. In the stochastic mode, the model is run 1,000 times for each subject using a Monte-Carlo procedure. The geometric means of the individual thyroid absorbed doses obtained in the stochastic mode range from 0.0006 to 55 Gy. The arithmetic and geometric means of these individual thyroid absorbed doses over the entire cohort are found to be 1.39 and 0.35 Gy, respectively. On average, the individual thyroid dose estimates obtained in the deterministic mode are about the same as the geometric mean doses obtained in the stochastic mode, while the arithmetic mean thyroid absorbed doses obtained in the stochastic mode are about 25% higher than those obtained in the deterministic mode. The distributions of the 1000 values of the individual thyroid absorbed dose estimates are found to be approximately lognormal, with geometric standard deviations ranging from 1.7 to 4.2 for most cohort subjects. For the time being, only the thyroid doses resulting from intakes of I 131 have been estimated for all subjects. Future work will include the estimation of the contributions to the thyroid doses resulting from external irradiation and from intakes of short-lived (I 133 and Te 132) and long-lived (Cs 134 and Cs 137) radionuclides, as well as efforts to reduce the uncertainties