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Gaschak S.P.,Chernobyl Center for Nuclear Safety | Maklyuk Y.A.,Chernobyl Center for Nuclear Safety | Maksimenko A.M.,Chernobyl Center for Nuclear Safety | Bondarkov M.D.,Chernobyl Center for Nuclear Safety | And 2 more authors.
Health Physics | Year: 2011

This article describes major studies performed by the Chernobyl Center's International Radioecology Laboratory (Slavutich, Ukraine) on radioecology of murine rodents and shrews inhabiting the Chernobyl Exclusion Zone. The article addresses the long-term (1986-2005) and seasonal dynamics of radioactive contamination of animals and reviews interspecies differences in radionuclide accumulations and factors affecting the radionuclide accumulations. It is shown that bioavailability of radionuclides in the "soil-to-plant" chain and a trophic specialization of animals play key roles in determining their actual contamination levels. The total absorbed dose rates in small mammals significantly reduced during the years following the Chernobyl Nuclear Power Plant accident. In 1986, the absorbed dose rate reached 1.3-6.0 Gy h -1 in the central areas of the Chernobyl Exclusion Zone (the "Red Forest"). In 1988 and 1990, the total absorbed dose rates were 1.3 and 0.42 Gy h -1, respectively. In 1995, 2000, and 2005, according to the present study, the total absorbed dose rates rarely exceeded 0.00023, 0.00018, and 0.00015 Gy h -1, respectively. Contributions of individual radiation sources into the total absorbed dose are described. Copyright © 2011 Health Physics Society.


Bondarkov M.D.,Chernobyl Center for Nuclear Safety | Maksimenko A.M.,Chernobyl Center for Nuclear Safety | Gaschak S.P.,Chernobyl Center for Nuclear Safety | Zheltonozhsky V.A.,Ukrainian Academy of Sciences | And 2 more authors.
Health Physics | Year: 2011

To perform in vivo simultaneous measurements of the Sr and Cs content in the bodies of animals living in the Chernobyl Exclusion Zone (ChEZ), an appropriate method and equipment were developed and installed in a mobile gamma beta spectrometry laboratory. This technique was designed for animals of relatively small sizes (up to 50 g). The Sr content is measured by a beta spectrometer with a 0.1-mm-thick scintillation plastic detector. The spectrum processing takes into account the fact that the measured object is "thick-layered" and contains a comparable quantity of Cs, which is a characteristic condition of the ChEZ. The Cs content is measured by a NaI scintillation detector that is part of the combined gamma beta spectrometry system. For environmental research performed in the ChEZ, the advantages of this method and equipment (rapid measurements, capability to measure live animals directly in their habitat, and the capability of simultaneous Sr and Cs measurements) far outweigh the existing limitations (considerations must be made for background radiation and the animal size, skeletal shape, and body mass). The accuracy of these in vivo measurements is shown to be consistent with standard spectrometric and radiochemical methods. Apart from the in vivo measurements, the proposed methodology, after a very simple upgrade that is also described in this paper, works even more accurately with samples of other media, such as soil and plants. Copyright © 2011 Health Physics Society.


Bondarkov M.D.,Chernobyl Center for Nuclear Safety | Oskolkov B.Y.,Chernobyl Center for Nuclear Safety | Gaschak S.P.,Chernobyl Center for Nuclear Safety | Kireev S.I.,State Specialized Scientific and Industrial Enterprise Chernobyl Radioecological Center | And 4 more authors.
Health Physics | Year: 2011

This paper describes results of the radiation environmental monitoring performed in the Chernobyl Exclusion Zone (ChEZ) during the period following the 1986 Chernobyl Nuclear Power Plant accident. This article presents a brief overview of five comprehensive reports generated under Contract No. DE-AC09-96SR18500 (Washington Savannah River Company LLC, Subcontract No. AC55559N, SOW No. ON8778) and summarizes characteristics of the ChEZ and its post-accident status. The history of development of the radiation monitoring research in the ChEZ is described also. This paper addresses the characteristics of radiation monitoring in the ChEZ, its major goals and objectives, and changes in these goals and objectives in the course of time, depending on the tasks associated with the phase of mitigation of the ChNPP accident consequences. The results of the radiation monitoring in the ChEZ during the last 25 years are also provided. Copyright © 2011 Health Physics Society.


Gashchak S.,Chernobyl Center for Nuclear Safety | Beresford N.A.,UK Center for Ecology and Hydrology | Maksimenko A.,Chernobyl Center for Nuclear Safety
Radiation and Environmental Biophysics | Year: 2010

Bats are a protected species and as such may be an object of protection in radiological assessments of the environment. However, there have previously been only few radioecological studies of species of bats. In this paper, results for >140 measurements of 90Sr and 137Cs in 10 species of bats collected within the Chernobyl zone are presented. There was some indication of a decreasing transfer of 90Sr with increasing deposition, although this was inconsistent across species and explained little of the observed variability. There was no difference between male and female bats in the transfer (expressed as the ratio of whole-body activity concentrations to those in soil) of either radionuclide. There was considerable variability in transfer across all species groups. At two sites where there were sufficient data, Eptesicus serotinus was found to have higher transfer than other species. © 2010 Springer-Verlag.


Gashchak S.,Chernobyl Center for Nuclear Safety | Estok P.,Chernobyl Center for Nuclear Safety | Kravchenko K.,Eszterházy Károly College
Hystrix | Year: 2015

Long distance recaptures of banded bats from Eastern European countries (Belarus, Ukraine, European part of Russia) have been lacking for decades. The last transboundary recapture was recorded in the late 1960s. We herewith report a new long-distance recapture of a noctule Nyctalus noctula). The fresh carcass of a ringed adult female noctule was found in South-East Hungary on 22 May 2014. The bat was mist-netted and ringed on 31 May 2011 on the territory of Chernobyl Exclusion Zone, in North Ukraine. The direct distance between the two locations is 800 km. © 2015, Associazione Teriologica Italiana.


PubMed | Institute for Radiological Protection and Nuclear Safety, Chernobyl Center for Nuclear Safety, CNRS Center of Evolutionary and Functional Ecology and Ecolab
Type: | Journal: The Science of the total environment | Year: 2016

The effects of radioactive contamination on ecosystem processes such as litter decomposition remain largely unknown. Because radionuclides accumulated in soil and plant biomass can be harmful for organisms, the functioning of ecosystems may be altered by radioactive contamination. Here, we tested the hypothesis that decomposition is impaired by increasing levels of radioactivity in the environment by exposing uncontaminated leaf litter from silver birch and black alder at (i) eleven distant forest sites differing in ambient radiation levels (0.22-15Gyh(-1)) and (ii) along a short distance gradient of radioactive contamination (1.2-29Gyh(-1)) within a single forest in the Chernobyl exclusion zone. In addition to measuring ambient external dose rates, we estimated the average total dose rates (ATDRs) absorbed by decomposers for an accurate estimate of dose-induced ecological consequences of radioactive pollution. Taking into account potential confounding factors (soil pH, moisture, texture, and organic carbon content), the results from the eleven distant forest sites, and from the single forest, showed increased litter mass loss with increasing ATDRs from 0.3 to 150Gyh(-1). This unexpected result may be due to (i) overcompensation of decomposer organisms exposed to radionuclides leading to a higher decomposer abundance (hormetic effect), and/or (ii) from preferred feeding by decomposers on the uncontaminated leaf litter used for our experiment compared to locally produced, contaminated leaf litter. Our data indicate that radio-contamination of forest ecosystems over more than two decades does not necessarily have detrimental effects on organic matter decay. However, further studies are needed to unravel the underlying mechanisms of the results reported here, in order to draw firmer conclusions on how radio-contamination affects decomposition and associated ecosystem processes.


Howard B.J.,UK Center for Ecology and Hydrology | Beresford N.A.,UK Center for Ecology and Hydrology | Copplestone D.,University of Stirling | Telleria D.,International Atomic Energy Agency | And 18 more authors.
Journal of Environmental Radioactivity | Year: 2013

An IAEA handbook presenting transfer parameter values for wildlife has recently been produced. Concentration ratios (CRwo-media) between the whole organism (fresh weight) and either soil (dry weight) or water were collated for a range of wildlife groups (classified taxonomically and by feeding strategy) in terrestrial, freshwater, marine and brackish generic ecosystems. The data have been compiled in an on line database, which will continue to be updated in the future providing the basis for subsequent revision of the Wildlife TRS values. An overview of the compilation and analysis, and discussion of the extent and limitations of the data is presented. Example comparisons of the CRwo-media values are given for polonium across all wildlife groups and ecosystems and for molluscs for all radionuclides. The CRwo-media values have also been compared with those currently used in the ERICA Tool which represented the most complete published database for wildlife transfer values prior to this work. The use of CRwo-media values is a pragmatic approach to predicting radionuclide activity concentrations in wildlife and is similar to that used for screening assessments for the human food chain. The CRwo-media values are most suitable for a screening application where there are several conservative assumptions built into the models which will, to varying extents, compensate for the variable data quality and quantity, and associated uncertainty. © 2012 Elsevier Ltd.


Vornam B.,University of Gottingen | Arkhipov A.,Chernobyl Center for Nuclear Safety | Finkeldey R.,University of Gottingen
Journal of Environmental Radioactivity | Year: 2012

In the Chernobyl exclusion zone forest trees have to tolerate and to adapt to ionizing radiation, therefore the molecular basis of their adaptive responses is of the utmost interest. Based on SNP analysis and real time PCR nucleotide diversity and expression profiles of gene fragments of catalase (Cat) and glutathione peroxidase (GPx), which are known as radical scavenging genes, were analysed in the needles of irradiated pine trees of the Chernobyl exclusion zone. In acutely and chronically irradiated trees (50 years old) planted before the accident a higher nucleotide diversity of Cat and more somatic mutations were found compared to their control. Chronically irradiated trees (20 years old) planted after the accident showed a similar nucleotide diversity of Cat compared to their control and in both collectives one somatic mutation was found. The nucleotide diversity of GPx was higher in all analysed trees compared to Cat. No somatic mutation events were found in GPx. For both gene fragments, no association between the received dose in a tree and the nucleotide diversity and mutation events was detected. The expression profiles of Cat and GPx in acutely and chronically and in chronically irradiated trees were similar. Compared to their corresponding control collectives, Cat was up-regulated and GPx slightly down-regulated. © 2011 Elsevier Ltd.


Beresford N.A.,UK Center for Ecology and Hydrology | Beresford N.A.,University of Salford | Gaschak S.,Chernobyl Center for Nuclear Safety | Maksimenko A.,Chernobyl Center for Nuclear Safety | Wood M.D.,University of Salford
Journal of Environmental Radioactivity | Year: 2016

Protected species are the focus of many radiological environmental assessments. However, the lack of radioecological data for many protected species presents a significant international challenge. Furthermore, there are legislative restrictions on destructive sampling of protected species to obtain such data. Where data are not available, extrapolations are often made from 'similar' species but there has been little attempt to validate this approach.In this paper we present what, to our knowledge, is the first study purposefully designed to test the hypothesis that radioecological data for unprotected species can be used to estimate conservative radioecolgical parameters for protected species; conservatism being necessary to ensure that there is no significant impact.The study was conducted in the Chernobyl Exclusion Zone. Consequently, we are able to present data for Pu isotopes in terrestrial wildlife. There has been limited research on Pu transfer to terrestrial wildlife which contrasts with the need to assess radiation exposure of wildlife to Pu isotopes around many nuclear facilities internationally.Our results provide overall support for the hypothesis that data for unprotected species can be used to adequately assess the impacts for ionising radiation on protected species. This is demonstrated for a range of mammalian and avian species. However, we identify one case, the shrew, for which data from other ground-dwelling small mammals would not lead to an appropriately conservative assessment of radiation impact. This indicates the need to further test our hypothesis across a range of species and ecosystems, and/or ensure adequate conservatism within assessments.The data presented are of value to those trying to more accurately estimate the radiation dose to wildlife in the Chernobyl Exclusion Zone, helping to reduce the considerable uncertainty in studies reporting dose-effect relationships for wildlife.A video abstract for this paper is available from: http://bit.ly/1JesKPc. © 2016 The Authors.


PubMed | University of Salford and Chernobyl Center for Nuclear Safety
Type: | Journal: Journal of environmental radioactivity | Year: 2016

Protected species are the focus of many radiological environmental assessments. However, the lack of radioecological data for many protected species presents a significant international challenge. Furthermore, there are legislative restrictions on destructive sampling of protected species to obtain such data. Where data are not available, extrapolations are often made from similar species but there has been little attempt to validate this approach. In this paper we present what, to our knowledge, is the first study purposefully designed to test the hypothesis that radioecological data for unprotected species can be used to estimate conservative radioecolgical parameters for protected species; conservatism being necessary to ensure that there is no significant impact. The study was conducted in the Chernobyl Exclusion Zone. Consequently, we are able to present data for Pu isotopes in terrestrial wildlife. There has been limited research on Pu transfer to terrestrial wildlife which contrasts with the need to assess radiation exposure of wildlife to Pu isotopes around many nuclear facilities internationally. Our results provide overall support for the hypothesis that data for unprotected species can be used to adequately assess the impacts for ionising radiation on protected species. This is demonstrated for a range of mammalian and avian species. However, we identify one case, the shrew, for which data from other ground-dwelling small mammals would not lead to an appropriately conservative assessment of radiation impact. This indicates the need to further test our hypothesis across a range of species and ecosystems, and/or ensure adequate conservatism within assessments. The data presented are of value to those trying to more accurately estimate the radiation dose to wildlife in the Chernobyl Exclusion Zone, helping to reduce the considerable uncertainty in studies reporting dose-effect relationships for wildlife. A video abstract for this paper is available from: http://bit.ly/1JesKPc.

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