Impacts of radiation exposure on the bacterial and fungal microbiome of small mammals in the Chernobyl Exclusion Zone.

Environmental impacts of the 1986 Chernobyl Nuclear Power Plant accident are much debated, but the effects of radiation on host microbiomes have received little attention to date. We present the first analysis of small mammal gut microbiomes from the Chernobyl Exclusion Zone in relation to total absorbed dose rate, including both caecum and faeces samples. We provide novel evidence that host species determines fungal community composition, and that associations between microbiome (both bacterial and fungal) communities and radiation exposure vary between host species.

Analysis of I and I in soils of the Chernobyl Exclusion Zone, 29 years after the deposition of I.

The Chernobyl Exclusion Zone (CEZ) represents a unique natural laboratory that received significant I contamination across a range of soils and land-use types in a short time period in 1986. Data are presented on I and I in soil samples collected from highly contaminated areas in the CEZ in 2015. The geometric mean (GM) total concentration of stable iodine (I) was 6.

Genome-wide DNA methylation changes in two Brassicaceae species sampled alongside a radiation gradient in Chernobyl and Fukushima.

The long-term radiological impact to the environment of the nuclear accidents in Chernobyl and Fukushima is still under discussion. In the course of spring of 2016 we sampled two Brassicacea plants, Arabidopsis thaliana and Capsella bursa-pastoris native to Ukraine and Japan, respectively, alongside a gradient of radiation within the exclusion and difficult to return zones of Chernobyl (CEZ) and Fukushima (FEZ). Ambient dose rates were similar for both sampling gradients ranging from 0.

Elevated mitochondrial genome variation after 50 generations of radiation exposure in a wild rodent.

Currently, the effects of chronic, continuous low dose environmental irradiation on the mitochondrial genome of resident small mammals are unknown. Using the bank vole () as a model system, we tested the hypothesis that approximately 50 generations of exposure to the Chernobyl environment has significantly altered genetic diversity of the mitochondrial genome. Using deep sequencing, we compared mitochondrial genomes from 131 individuals from reference sites with radioactive contamination comparable to that present in northern Ukraine before the 26 April 1986 meltdown, to populations where substantial fallout was deposited following the nuclear accident.

Inter-cultivar variation in soil-to-plant transfer of radiocaesium and radiostrontium in Brassica oleracea.

Radiocaesium and radiostrontium enter the human food chain primarily via soil-plant transfer. However, uptake of these radionuclides can differ significantly within species (between cultivars). The aim of this study was to assess inter-cultivar variation in soil-to-plant transfer of radiocaesium and radiostrontium in a leafy crop species, Brassica oleracea.

The transfer of (137)Cs, Pu isotopes and (90)Sr to bird, bat and ground-dwelling small mammal species within the Chernobyl exclusion zone.

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.

Soil nematode assemblages as bioindicators of radiation impact in the Chernobyl Exclusion Zone.

In radioecology, the need to understand the long-term ecological effects of radioactive contamination has been emphasised. This requires that the health of field populations is evaluated and linked to an accurate estimate of received radiological dose. The aim of the present study was to assess the effects of current radioactive contamination on nematode assemblages at sites affected by the fallout from the Chernobyl accident.

Radioadaptive response following in utero low-dose irradiation.

Acute radiation exposure is known to cause biological damage that leads to severe health effects. However, the effects and subsequent health implications of exposure to low doses of ionizing radiation are unclear. The purpose of this study was to investigate the effects of low-dose ionizing radiation exposures in utero.

Environmental radiation monitoring in the Chernobyl exclusion zone--history and results 25 years after.

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.

Radiation ecology issues associated with murine rodents and shrews in the Chernobyl exclusion zone.

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.

Frequency distributions of 90Sr and 137Cs concentrations in an ecosystem of the "Red Forest" area in the Chernobyl exclusion zone.

In the most highly contaminated region of the Chernobyl Exclusion Zone, the "Red Forest" site, the accumulation of the major dose-affecting radionuclides (90Sr and 137Cs) within the components of an ecological system encompassing 3,000 m(2) was characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants), and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the 90Sr and 137Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values was close to a logarithmically-normal leptokurtic distribution with a significant right-side skew.

Method for simultaneous 90Sr and 137Cs in-vivo measurements of small animals and other environmental media developed for the conditions of the Chernobyl exclusion zone.

To perform in vivo simultaneous measurements of the 90Sr and 137Cs 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 90Sr content is measured by a beta spectrometer with a 0.

Radiation dose assessment for the biota of terrestrial ecosystems in the shoreline zone of the Chernobyl nuclear power plant cooling pond.

Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. This paper addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software.

Overview of the cooperation between the Chernobyl Center's International Radioecology Laboratory in Slavutych, Ukraine, and U.S. research centers between 2000 and 2010.

The International Radioecology Laboratory (IRL) located in Slavutych, Ukraine, was created in 1999 under the initiative of the United States Government and the Government of Ukraine in the framework of international cooperation on evaluation and minimization of consequences of the Chernobyl nuclear power plant (ChNPP) accident. Since the time the IRL was founded, it has participated in a large number of projects, including the following: 1) study of radionuclide accumulation, distribution, and migration in components of various ecological systems of the Chernobyl Exclusion Zone (ChEZ); 2) radiation dose assessments; 3) study of the effects of radiation influence on biological systems; 4) expert analysis of isotopic and quantitative composition of radioactive contaminants; 5) development of new methods and technologies intended for radioecological research; 6) evaluation of future developments and pathways for potential remediation of the ChEZ areas; 7) assistance in provision of physical protection systems for ionizing irradiation sources at Ukrainian enterprises; 8) reviews of open Russian language publications on issues associated with consequences of the ChNPP accident, radioactive waste management, radioecological monitoring, and ChNPP decommissioning; 9) conduct of training courses on problems of radioecology, radiation safety, radioecological characterization of test sites and environmental media, and research methods; 10) conduct of on-site scientific conferences and workshops on the ChEZ and radioecology problems; participation in off-site scientific conferences and meetings; and 11) preparation of scientific and popular science publications and interactions with mass media representatives. This article provides a brief overview of the major achievements resulting from this cooperation between the IRL and U.

Assessment of (90)sr and (137)cs penetration into reinforced concrete (extent of "deepening") under natural atmospheric conditions.

When assessing the feasibility of remediation following the detonation of a radiological dispersion device or improvised nuclear device in a large city, several issues should be considered, including the levels and characteristics of the radioactive contamination, the availability of resources required for decontamination and the planned future use of the city's structures and buildings. Currently, little is known about radionuclide penetration into construction materials in an urban environment. Knowledge in this area would be useful when considering costs of a thorough decontamination of buildings, artificial structures and roads in an affected urban environment.

Assessment of beta particle flux from surface contamination as a relative indicator for radionuclide distribution on external surfaces of a multistory building in Pripyat.

Several issues should be considered when assessing the feasibility of remediation following the detonation of a radiological dispersion device (e.g., dirty bomb) or improvised nuclear device in a large city.

The effects of environmental low-dose irradiation on tolerance to chemotherapeutic agents.

The nuclear disaster at Chernobyl, Ukraine, in April of 1986 continues to impact the environment on many different levels. Studies of epidemiological, environmental, and genetic impacts have been prolific since the accident, revealing interesting results concerning the effects of radiation. The long-tailed field mouse, Apodemus flavicollis, was collected from distinct localities near the Chernobyl site and evaluated based on in vivo responses to the current clinically employed chemotherapeutic agents bleomycin (BLM) and vinblastine (VBL), as well as the immune modulator lipopolysaccharide (LPS).

Environmental problems associated with decommissioning the Chernobyl Nuclear Power Plant Cooling Pond.

Decommissioning of nuclear power plants and other nuclear fuel cycle facilities associated with residual radioactive contamination of their territories is an imperative issue. Significant problems may result from decommissioning of cooling ponds with residual radioactive contamination. The Chernobyl Nuclear Power Plant (ChNPP) Cooling Pond is one of the largest self-contained water reservoirs in the Chernobyl region and Ukrainian and Belorussian Polesye region.

Predicting the radiation exposure of terrestrial wildlife in the Chernobyl exclusion zone: an international comparison of approaches.

There is now general acknowledgement that there is a requirement to demonstrate that species other than humans are protected from anthropogenic releases of radioactivity. A number of approaches have been developed for estimating the exposure of wildlife and some of these are being used to conduct regulatory assessments. There is a requirement to compare the outputs of such approaches against available data sets to ensure that they are robust and fit for purpose.

Understanding the genetic consequences of environmental toxicant exposure: Chernobyl as a model system.

We sampled vole populations in Ukraine with the dual goal of characterizing population diversity and of providing a biogeographic perspective to evaluate experimental designs used for previous studies. Our data indicate that genetic diversity in bank vole populations is widely variable across regions and that diversity estimates in contaminated sites are unremarkable compared to those in uncontaminated areas. Furthermore, the relative frequencies of haplotypes have remained statistically identical throughout multiple sampling periods.

Modelling of a large-scale urban contamination situation and remediation alternatives.

The Urban Remediation Working Group of the International Atomic Energy Agency's EMRAS (Environmental Modelling for Radiation Safety) program was organized to address issues of remediation assessment modelling for urban areas contaminated with dispersed radionuclides. The present paper describes the first of two modelling exercises, which was based on Chernobyl fallout data in the town of Pripyat, Ukraine. Modelling endpoints for the exercise included radionuclide concentrations and external dose rates at specified locations, contributions to the dose rates from individual surfaces and radionuclides, and annual and cumulative external doses to specified reference individuals.

Improvement of modelling capabilities for assessing urban contamination: the EMRAS Urban Remediation Working Group.

The Urban Remediation Working Group of the International Atomic Energy Agency's Environmental Modelling for Radiation Safety (EMRAS) programme was established to improve modelling and assessment capabilities for radioactively contaminated urban situations, including the effects of countermeasures. An example of the Working Group's activities is an exercise based on Chernobyl fallout data in Ukraine, which has provided an opportunity to compare predictions among several models and with available measurements, to discuss reasons for discrepancies, and to identify areas where additional information would be helpful.

Estimating the exposure of small mammals at three sites within the Chernobyl exclusion zone--a test application of the ERICA Tool.

An essential step in the development of any modelling tool is the validation of its predictions. This paper describes a study conducted within the Chernobyl exclusion zone to acquire data to conduct an independent test of the predictions of the ERICA Tool which is designed for use in assessments of radiological risk to the environment. Small mammals were repeatedly trapped at three woodland sites between early July and mid-August 2005.