[en] It has been described the results of thyroid dose reconstruction for inhabitants of the Republic of Belarus. 1. About 130,000 individual thyroid dose estimates for inhabitants from 900 settlements have been done on the basis of the measurements of human thyroidal ¹³¹I content. 2. As a result of passportization of above mentioned 900 settlements it is possible to estimate individual thyroid doses additionally for 160,000 rural residents and 2,500,000 urban residents from cities: Minsk, Gomel, Mogilev, and Mozyr. 3. On the basis of the relationship obtained between the arithmetic mean thyroid dose for adults and the radionuclide deposition density in settlements the method has been developed to estimate thyroid doses for any inhabitant of the Republic if there is the data of radionuclide deposition density. 4. It has been considered the main thesis of the developed semiempirical model for thyroid dose formation as a result of the Chernobyl accident. In the simplest way it has been formulated. 5. The main approaches to get the most adequate individual thyroid dose estimated according to variants 2 and 3, including approaches with using data of deposition density of ¹²⁹I, ¹³¹I, ¹³⁷Cs have been formulated. 6. It has been presented the results of assessment (according to the model accepted by UNSCEAR) of additional number of the cancer cases among the population of the Republic of Belarus versus the observed number of the cancer cases. (J.P.N.)

[en] The results of direct measurements of radioactive iodine content in the human thyroid gland (in Bryansk and Kaluga regions, Russia) and also available data on ¹³¹I and ¹³⁷Cs contamination of the soil were used for investigation of correlations between the mean thyroid dose for adults in settlements and local levels of ¹³⁷Cs and/or ¹³¹I soil contamination. On the basis of this analysis a model was developed showing how to evaluate retrospectively the thyroid absorbed doses. For individual dose reconstruction using an 'age/milk' scale, special questioning of inhabitants was carried out. Mean dose values in the exposed population of each contaminated Russian settlement were evaluated using the model. The total collective dose due to internal exposure of the thyroid gland by iodine radionuclides equates to 106,500 person.Gy in the population of the most contaminated territories of four Russian regions. The maximum value was found in the Bryansk region (73,000 person.Gy). New data concerning the delay in pasturing in different regions as well as time dependencies of the fallout were taken into account. As a result the dose estimations differ from previous published data. Comparisons between the developed method and the other independent approaches indicate a concordance within a factor 3. For application of the EPR tooth enamel dosimetry on a wide scale, estimation of accumulated external doses are demonstrated and analysed. There were about 2500 tooth samples measured from the contaminated region as well as from the non-contaminated territories of Russia. The investigated factors are: (1) effect of solar light on front teeth; (2) correction for the energy dependence of the EPR response; (3) presence in the enamel of some intrinsic signals; (4) age dependent doses due to natural background radiation. The average values of EPR dose with special account taken of correction factors are presented. The tendency of average doses to grow with the level of ¹³⁷Cs contamination of settlements was found (the linear regression with the slope equates to 2.4 ± 0.5 mGy per Ci.km^-2). This tendency is close to that of analytical calculations. (author)

No abstract available

[en] The aim of this study to investigate peculiarities of thyroid pathology development of children exposed to radiation in utero and within the first year of life. In 1998, the 12 years after the Chernobyl accident, two cohorts of children aged 11-14 in Khoiniki region and Braslav region were screened. Minimum average dose to the thyroid was in children exposed in utero - 36 cGy. Maximum average thyroid dose was registered in children exposed at 0-1.5 years old on mixed nutrition - 110 cGy

[en] Regulatory cooperation between the Norwegian Radiation Protection Authority and the Federal Medical Biological Agency (FMBA) of the Russian Federation has the overall goal of promoting improvements in radiation protection in Northwest Russia. One of the projects in this programme has the objectives to review and improve the existing medical emergency preparedness capabilities at the sites for temporary storage of spent nuclear fuel and radioactive waste. These are operated by SevRAO at Andreeva Bay and in Gremikha village on the Kola Peninsula. The work is also intended to provide a better basis for regulation of emergency response and medical emergency preparedness at similar facilities elsewhere in Russia. The purpose of this paper is to present the main results of that project, implemented by the Burnasyan Federal Medical Biophysical Centre. The first task was an analysis of the regulatory requirements and the current state of preparedness for medical emergency response at the SevRAO facilities. Although Russian regulatory documents are mostly consistent with international recommendations, some distinctions lead to numerical differences in operational intervention criteria under otherwise similar conditions. Radiological threats relating to possible accidents, and related gaps in the regulation of SevRAO facilities, were also identified. As part of the project, a special exercise on emergency medical response on-site at Andreeva Bay was prepared and carried out, and recommendations were proposed after the exercise. Following fruitful dialogue among regulators, designers and operators, special regulatory guidance has been issued by FMBA to account for the specific and unusual features of the SevRAO facilities. Detailed sections relate to the prevention of accidents, and emergency preparedness and response, supplementing the basic Russian regulatory requirements. Overall it is concluded that (a) the provision of medical and sanitary components of emergency response at SevRAO facilities is a priority task within the general system of emergency preparedness; (b) there is an effective and improving interaction between SevRAO and the local medical institutions of FMBA and other territorial medical units; (c) the infrastructure of emergency response at SevRAO facilities has been created and operates within the framework of Russian legal and normative requirements. Further proposals have been made aimed at increasing the effectiveness of the available system of emergency preparedness and response, and to promote interagency cooperation.

No abstract available

[en] Within weeks of the Chernobyl accident, about 300000 measurements of human thyroidal ¹³¹I content were conducted in the more contaminated territories of the Republic of Belarus. Results of these and other measurements form the basis of thyroid-dose reconstruction for residents of Belarus. Preliminary estimates of thyroid doses have been divided into three classes. Class 1 ('measured' doses). Individual doses are estimated directly from the measured thyroidal ¹³¹I content of the person considered, plus information on life style and dietary habits. Such estimates are available for about 130000 individuals from the contaminated areas of Gomel and Mogilev Region and Minsk city. Class 2 ('passport' doses). For every settlement with a sufficient number of residents with 'measured' doses, individual thyroid-dose distributions are determined for several age groups and levels of milk consumption. This action has been called the 'passportization' of the settlement. A population of about 2.7 million people resides in the 'passportized' settlements. Class 3 ('inferred' doses). For any settlement where the number of residents with 'measured' doses is small or equal to zero, individual thyroid doses are derived from the relationship obtained between the mean adult-thyroid dose and the deposition density of ¹³¹I or ¹³⁷Cs in settlements with 'passport' doses presenting characteristics similar to those of the settlement considered. This method can be applied to the remainder of the population (about 7.3 million people). An approximate estimate of the collective thyroid dose for the residents of Belarus is presented. Illustrative results of individual thyroid dose and associated uncertainty are discussed for rural settlements and urban areas

[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

[en] Full text: The retrospective estimates of settlement average thyroid dose for the residents of all settlements (2,205) in Brest Region of Belarus are presented. Calculations have been done assuming primarily milk intake of radioiodine that was typical for each of 19 age-groups (18 groups for children aged 0 to 17 and one group for adults 18 y and older). Methodical approaches will be briefly explained. A semi-empirical model was used as the basis for thyroid dose reconstruction. Input parameters for this model are the data on integrated deposition of dry, wet (with rains) or a mixture of dry and wet fallout of I-131. Necessary information is available only for 8 cities in Belarus, including 3 cities in the Brest Region. Thus, the method to reconstruct the I-131 integrated deposition densities in the settlements of Brest Region has been obtained. Five variants of the method depending on available set of input dosimetric information related to a settlement have been evaluated. Of total number of settlements 2,205, for 2,183 settlements the method of retrospective assessment was based on the data on the Cs-137 ground deposition density. In that case the basis of the developed method is developed by using the revealed dependency between the ratio of I-131 to Cs-137 in fallout and of the contribution of wet to total integrated deposition of I-131 versus the level of the Cs-137 ground deposition density

No abstract available