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The rate constants of 137Cs uptake in Prussian carp (Carassius gibelio) from the water with a potassium content of 2 mg·L-1 at T = 5 °C without feeding (kw = 0.045 ± 0.001 day-1), at T = 12 °C with «clean» feeding (0.046 ± 0.002 day-1) and at T = 22 °C with «clean» feeding (0.062 ± 0.006 day-1) were obtained in a series of aquarium experiments. The results showed that rates of 137Cs uptake in fish from water without and with feeding did not significantly differ at different temperatures of water (T = 5 - 22 °C) and were two orders of magnitude lower than the rate constants of 137Cs uptake in Prussian carp with feed in Chornobyl exclusion zone (11.4 ± 2.6 day-1). This makes it possible to obtain products with 137Cs content below the permissible level (150 Bq·kg-1) while providing fish with clean feeds even in the most radioactively contaminated reservoirs of the exclusion zone. A decrease in the potassium content in water from 2 to 0.2 mg·L-1 (no feeding, T = 5 ± 1 °C) resulted in an increase in the rate of 137Cs uptake into the fish from the water by 1.6 times. An increase in the potassium content in water by 10 times up to 20 mg L-1 resulted just in a decrease of 20 % in the rate. The levels of 137Cs activity concentration in fish in contaminated water at temperatures below 10 °C will be two orders of magnitude lower compared to radioactive contamination of water in the summer season (T = 22 °C). This is extremely important for the correct prediction of fish contamination in the autumn-winter-spring period at a water temperature of less than 10 °C when some fish stop feeding.

Freshwater fish such as Prussian carp (Carassius gibelio) don’t need a feed at a water temperature below 10 °С. To study the rate constants of 137Cs excretion from the body of Prussian carp at different water temperatures (5 and 22 °С) and different feeding, the series of aquarium experiments were conducted. The half-life time of 137Cs activity excretion from fish in the water (T = 5 °С) without feeding (T1/2= 433 ± 162 days) was 5.6 times higher compared to the rate constants for water temperature 22 °С (T1/2 = 78 ± 4 days) with different types of feeding. The temporal decline of 137Cs activity (Bq) in fish was the same for different feeds, but the activity concentration of 137Cs (Bq·kg-1) in fish differed up to 1.8 times (0.0089 ± 0.0005 day-1 and 0.016 ± 0.002 day-1) due to different weight gains.

The rate constants of 137Cs uptake in Prussian carp (Carassius gibelio) from the water with a potassium content of 2 mg∙L-1 at T = 5 °C without feeding (kw = 0.045 ± 0.001 day-1), at T = 12 °C with «clean» feeding (0.046 ± 0.002 day-1) and at T = 22 °C with «clean» feeding (0.062 ± 0.006 day-1) were obtained in a series of aquarium experiments. The results showed that rates of 137Cs uptake in fish from water without and with feeding did not significantly differ at different temperatures of water (T = 5 -22 °C) and were two orders of magnitude lower than the rate constants of 137Cs uptake in Prussian carp with feed in Chornobyl exclusion zone (11.4 ± 2.6 day-1). This makes it possible to obtain products with 137Cs content below the permissible level (150 Bq∙kg-1) while providing fish with clean feeds even in the most radioactively contaminated reservoirs of the exclusion zone. A decrease in the potassium content in water from 2 to 0.2 mg∙L-1 (no feeding, T = 5 ± 1 °C) resulted in an increase in the rate of 137Cs uptake into the fish from the water by 1.6 times. An increase in the potassium content in water by 10 times up to 20 mg L-1 resulted just in a decrease of 20 % in the rate. The levels of 137Cs activity concentration in fish in contaminated water at temperatures below 10 °C will be two orders of magnitude lower compared to radioactive contamination of water in the summer season (T = 22 °C). This is extremely important for the correct prediction of fish contamination in the autumn-winter-spring period at a water temperature of less than 10 °C when some fish stop feeding. [ABSTRACT FROM AUTHOR]

Freshwater fish such as Prussian carp (Carassius gibelio) don't need a feed at a water temperature below 10 °С. To study the rate constants of 137Cs excretion from the body of Prussian carp at different water temperatures (5 and 22 °С) and different feeding, the series of aquarium experiments were conducted. The half-life time of 137Cs activity excretion from fish in the water (T = 5 °С) without feeding (T1/2 = 433 ± 162 days) was 5.6 times higher compared to the rate constants for water temperature 22 °С (T1/2 = 78 ± 4 days) with different types of feeding. The temporal decline of 137Cs activity (Bq) in fish was the same for different feeds, but the activity concentration of 137Cs (Bq-kg-1 ) in fish differed up to 1.8 times (0.0089 ± 0.0005 day-1 and 0.016 ± 0.002 day-1 ) due to different weight gains. [ABSTRACT FROM AUTHOR]

The article identifies the main groups of historical sources for a comprehensive study of Soviet information policy with respect to the Chernobyl accident. Determine their informational potential, deals with the methods of source analysis.

Assessment is given of area and behavior of large wildfire in the Chornobyl Exclusion Zone (ChEZ) which has been burning during April 27 - 29, 2015. Levels of radionuclide contamination of combustible material show that expected effective dose of firefighters during one fire-line hour did not exceed 0.64 μSv in case of external exposure and 0.37 μSv in case of internal exposure. It is shown that the expected effective dose of internal exposure of firefighters during suppression of wildfires in ChEZ was below the dose from external exposure. At the moment exposures of 90Sr and 241Pu (along with 238-240Pu and 241Am) make the most significant contribution to the internal dose of firefighters during forest and grassland fires suppression in the ChEZ.

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Assessment of area and behavior of large wildfire in the Chornobyl Exclusion Zone (ChEZ) which has been burning during April 27 - 29, 2015. Levels of radionuclide contamination of combustible material show that expected effective dose of firefighters during one fire-line hour did not exceed 0.64 pSv in case of external exposure and 0.37 pSv in case of internal exposure. It is shown that the expected effective dose of internal exposure of firefighters during suppression of wildfires in ChEZ were below the dose from external exposure. At the moment exposure of 90Sr ad 241Pu (along with 238-240Pu and 241Am) make the most significant contribution to the internal dose of firefighters during forest and grassland fires suppression in the ChEZ. [ABSTRACT FROM AUTHOR]

The objective of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of after-math of the Chornobyl accident through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring. The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014. The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 raions in 12 oblasts during all the post-accident period. Thanks to the works of dosimetric pass-portization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important radiological parameters, namely over 500 thousands of measurements of concentration of 137Cs and 90Sr in the local foodstuff (milk and potatoes); there are more than 1.3 million of measurements of the cesium content in the body of residents of the settlements of Ukraine; there are 100 thousands of dose estimates (both internal and external ones were measured separately) of inhabitants living on the radioactively contaminated areas. The results of the dosimetric passportization served as one of the main exposure criteria for generalized aftermath of the Chornobyl accident represented in the National reports for the first 15, 20 and 25 years after the accident. [ABSTRACT FROM AUTHOR]

Since 2007, the department of dosimetry of NRCRM has been working for to supply the Ukrainian State Register (SRU) of persons affected due to Chornobyl accident by exposure doses estimations. As of now, the individualization of doses has been performed for nine raions located in Kyiv, Zhytomyr, Rivne and Chernihiv oblasts. The structure of raion-specific models used for the reconstruction of individualized doses was described in detail in the previous 19-th issue of this Journal (2014). The choice conditions for persons from the SRU using which for each raion there was formed a contingent of persons for whom the dose could be reconstructed. During the period of 2007-2015, the individualized dose was reconstructed for 244226 persons in 9 raions, representing ~ 58% of all registered in the SRU inhabitants of the raions. The calculation results were transferred to the SRU in formats adapted to the common database structure of the SRU. For each person who satisfied the conditions of selection there were estimated: 1) possible absorbed internal exposure dose of the thyroid by radioiodine in 1986 (assuming that the person in 1986 lived in the same village where he/she was enlisted in the SRU); 2) annual doses of external, internal and total exposure of the whole body for a period of observation in the SRU; 3) total exposure dose of whole body accumulated during the period of observation in the SRU; 4) the total cumulative dose of feasible exposure during the period since 1986 till the decision to be registered in the SRU. There are presented the generalized results of the SRU subjects distribution for different raions in dependence on intervals of doses accumulated at different periods after the accident. The raion matrix tables show the dynamics of accumulation of doses by the SRU subjects both for their stay on the account and for the period of their possible residence in the settlement of registration since 1986. The directions for further research to be implemented for increasing the number of persons for whom it is possible to calculate individualized dose have been formulated. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the review is to demonstrate the results of dosimetric passportization (performed in 1991-2014) for the settlements of Ukraine which suffered from radioactive contamination caused by the Chornobyl accident. The dosimetric passportization played a key role in the National program on the liquidation of aftermath of the Chornobyl accident directed on recovery through all stages of the current radiation situation control and decision support touching upon various types of interventions and social benefits to the population of radioactively contaminated areas. The works being performed under dosimetric passportization did not have analogues among the researches which took place after other large-scale industrial and municipal accidents as well their scales as the duration of both radio-ecological and dosimetric monitoring.The new methodological approaches to the assessment of so-called passport doses of a settlement as well as to the definition of the concept of annual dose being the dose used to make decisions for providing both direct and indirect emergency countermeasures for the settlements of Ukraine became pioneering ones. During all the post-accident period there were issued sixteen collections of general dosimetric passportization data which accumulate the results of hundreds of thousands spectrometric, radiochemical and radiation levels measurements and WBC measurements carried out in 1991-2014.The annual passport doses calculated on the basis of these measurements (including their components) are unique information that quantifies the level and time dynamics of the radiation situation for each of the 2161 settlements of 74 raions in 12 oblasts during all the post-accident period. Thanks to the works of dosimetric passportization of the settlements of Ukraine there were created databases to be unique in their structure and content with quantitative characteristics of the territorial and temporal distribution, the dynamics of changes of a number of important radiological parameters, namely over 500 thousands of measurements of concentration of 137Cs and 90Sr in the local foodstuff (milk and potatoes); there are more than 1.3 million of measurements of the cesium content in the body of residents of the settlements of Ukraine; there are 100 thousands of dose estimates (both internal and external ones were measured separately) of inhabitants living on the radioactively contaminated areas. The results of the dosimetric passportization served as one of the main exposure criteria for generalized aftermath of the Chornobyl accident represented in the National reports for the first 15, 20 and 25 years after the accident., (I. A. Likhtarov, L. M. Kovgan, S. V. Masiuk, O. M. Ivanova, M. I. Chepurny.)

Study objective. Development a system of models and procedures for the individualized internal exposure doses reconstruction for the subjects of Ukrainian State Register of persons, affected due to the Chornobyl accident (SRU) and residing in radioactive contaminated territories of Kozelets and Ripky raions of Chernihiv oblast. Materials and methods. A description the schematic diagram and mathematical equations of ecological-dosimetric models are given that allow to reconstruct the individualized exposure doses from consumption of food contaminated with radiocesium of Chornobyl origin for inhabitants of two raions of Chernihiv oblast. Parameterization of the reconstruction models is based on the mathematical analysis of results for radioecological (radiocesium milk contamination) and dosimetric (radiocesium human body burden) monitorings, that were calculated in the period of 1986-2012 in the settlements of raions under consideration. Due to quite low level of radioactive cesium depositions on the ground in 1986, the territory of these raions was divided into two "territorial zones": TZ-1, an area where the 137Cs ground depositions density in 1986 exceeds 37 kBq/m2, and TZ-2, an area where this rate does not exceeds 37 kBq/m2. For each territorial zone in each raion, the initial time moment (year) was introduced in the reconstruction model. Since this year the concept of the so-called "reference dose" has been using. Its value was assigned to all persons, regardless of the results and availability of monitoring. The results of radioecological and dosimetric monitorings were used for setting in raion specific functions: the annual average concentration of 137Cs in milk per unit of 137Cs ground depositions for Kozelets raion, function of the temporary dynamic of 137Cs concentration in milk for Ripky raion, absolute raion milk equivalent of the diet (ARMEr), and relative age dependent intake of radiocesium with the diet. Results and conclusions. Models for individualized internal exposure doses reconstruction were applied to 27811 SRU subjects from Kozelets raion and 14553 SRU subjects from Ripky raion. Results of doses individualization are given as annual average values of internal and summarized (internal and external) exposure doses for the period of 1987-2012, as well as the distribution of SRU subjects of different raions according to the intervals of accumulat-ed doses over the entire period of observation., (I. A. Likhtarov, L. N. Kovgan, S. V. Masiuk, О. N. Ivanova, M. I. Chepurny, Z. N. Boyko, V. B. Gerasymenko, S. A. Tereshchenko, I. G. Kravchenko, G. I. Kortushin, O. D. Marcenjyk.)

Study objective. Dosimetric support of the Ukrainian State Register of persons, affected due to the Chornobyl accident (SRU). Development the system of models and procedures for the individualized internal doses reconstruction for the subjects of SRU residing in radioactive contaminated territories of Rokytne raion of Rivne oblast, Ovruch raion of Zhytomyr oblast and Ivankiv raion of Kyiv oblast. Materials and methods. A detailed description for the schematic diagram of the methodology and mathematical relations of ecological-dosimetric models are given. It allows to reconstruct the individualized doses from the ingestion of food contaminated by radiocesium after the Chornobyl accident for the subjects of SRU from three raions of Rivne, Zhytomyr and Kyiv oblasts. Phenomenologically, the developed models are close to the previously developed complex of ecological and dosimetric models intended to estimate the reference doses for the entire population of Ukraine. Calibration of model parameters is based on mathematical treatment for results of extensive radioecological (radiocesium milk contamination) and dosimetric (radiocesium burden in human body) monitorings, that were provided in the period of 1986-2012 in the settlements of raions under consideration. Completeness and periodicity of radioecological and dosimetric monitorings allowed to realize the settlement-specific approach for dose reconstruction, wherein for each settlement either the function of radiocesium intake with diet or the function of time-variation of radiocesium concentration in the local cow's milk were established. Absolute raion milk equivalent of the diet (ARMEr) and relative age dependent intake of radiocesium with diet are specified as a raion-specific functions for each raion. ARMEr is used to calculate the doses of adults in the settlement for which the function was specified. RRI is used to calculate the doses for the subjects of four children age groups (< 2 years old, 3-7 years old, 8-12 years old, 13-17 years old). Results and conclusions. Models for individualized internal exposure doses reconstruction of SRU subjects are developed. The individualized doses are estimated for 28711 SRU subjects from Rokytne raion, 18790 SRU subjects from Ivankiv raion and 41585 SRU subjects from Ovruch raion. Results of doses individualization are given as annual average doses for the period of 1987-2012. The distribution of SRU subjects of different raions over the intervals of doses accumulated over the entire observation period is also given. Values of total (from internal and external exposure) doses for SRU subjects of the raions under consideration are given, as well., (I. A. Likhtarov, L. N. Kovgan, S. V. Masiuk, О. N. Ivanova, M. I. Chepurny, Z. N. Boyko, V. B. Gerasymenko, S. A. Tereshchenko, I. G. Kravchenko, G. I. Kortushin, O. D. Marcenjyk.)