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Analysis of the population-genetic consequences of technogenic catastrophes, e.g., Chernobyl, is of special interest in connection with the development of global ecological changes and rising technogenic contamination. Research on the dynamics of cytogenetic anomalies in bone marrow cells of different Rodentia species (trapped in the alienation zone near Chernobyl’s NPP in 1994-2001 in places with different levels of contamination from 5 up to 1000 Ci/km2) and in peripheral blood cells of cattle generations of experimental herd (Pripjat, 200 Ci/km2) were carried out. The changes of genetic structure in cattle generations were analyzed employing family analysis of allele’s transfer in structural genes and ISSRPCR markers. Increases of mutant animals were not detected, but a reversal of genetic structure in cattle generations from an initial breed to ones, typical for more primitive breed was revealed. Our results indicate that ionizing radiation does not induce new genetic anomalies but allows realization of inherently unstable species- and individual-specific genetic characteristics.

The genetic effects of environmental pollution in Armenia are presented. Most of them are underway at Yerevan State University in cooperation with other institutions in Armenia, Germany, France and USA. The results of genetic monitoring of effects of environmental pollution obtained by different methods are presented. The routine analyses of chromosomal aberrations in groups of genetic risk can give data only about nonspecific action of environmental pollutants. The detection of genotoxic effects became more differentiated after studying –clastogenic factors (ultrafiltrates of blood plasma). FISH analysis was used in groups of patients with leukemia and inborn defects. We applied the Comet Assay to study DNA damage and repair in leukocytes of Chernobyl accident liquidators and patients with familial Mediterranean fever. The results showed an increased sensitivity or changed repair capacity of DNA of their cells exposed to UV-C. Analysis of micronuclei induction in exfoliated cells revealed the significant increase of chromosomal damage and their nondisjunction in the groups exposed to mutagens. For the investigation of groups of genetic risk in human populations we apply programmes with combination of presented methods. Cytogenetic programmes are usually combined with epidemiological data. Our research group is responsible for the genetic monitoring of the Armenian nuclear power plant and its environment. The results of chromosomal and point mutations monitoring in plants are presented.

The aim of this study was to compare the level of somatic mutagenesis in women with benign tumors of the reproductive system living in radiation contaminated regions of the Russian Federation with that in unexposed healthy individuals. Frequency of peripheral blood lymphocytes bearing mutations at T-cell receptor (TCR) locus was assessed by flow cytometry in 219 patients with myoma who had been living in Novozibkovskiy, Klintsovskiy districts of Bryansk region and Uzlovaya district of Tula region for 17-19 years since the moment of the Chernobyl accident. Mean ^137Cs densities in these districts were 708, 322 and 171 kBq/m^2 accordingly. The control group included 42 age-matched unexposed healthy individuals. There was no significant elevation in the TCR mutant cell frequency in patients from Uzlovaya district which was contaminated with radionuclides at low level in comparison to controls. The frequency of the TCR-mutant cells was significantly higher in patients from the most contaminated district (Novozibkovskiy and Klintsovskiy) as compared to the control group by Mann-Whitney test (p<0.05). Median values were 4.3˙10^-4, 5.9˙10^-4, 3.8˙10^-4 accordingly. However, only 19% of the patients had the TCR–mutant cell frequencies exceeding the 95% confidence interval in the control group (>7,0˙10^-4). The frequencies of mutant cells in other patients corresponded to those in the control group. Our results confirm that the TCR–method may be used for individual assessment of long-term health consequences after irradiation. Individuals with elevated TCR-mutant cell scores might belong to a high-risk group potentially prone to the development of neoplasm and need more thorough medical observation than the rest of population.

On the decree of the Russian Federation Government N 948 of 22 September 1993 the National Radiation and Epidemiological Registry was established. This is a legal entity on the base of the Medical Radiological Research Center of Russian Academy of Medical Sciences. Two main tasks were imposed upon the Registry: 1) objective estimation of radiation risks of cancer and non-cancer diseases following exposure to low dose radiation (up to 0.2 Sv); and 2) producing recommendations for health-care system and medical aid for minimization of delayed consequences of the Chernobyl accident. National registry comprises personal information on 615,000 people exposed to ionizing radiation, a far larger number than in the atomic bomb survivor registry. In this paper, basic information on radiation-epidemiologic analysis related to emergency accident workers and the population of Russian territories contaminated with radionuclides is summarized.

The 60th anniversary of the Hiroshima-Nagasaki atomic bombings was commemorated in August 2005. By the end of 1945, according to the reports from both city governments, 140,000 and 70,000 deaths had occurred among inhabitants in Hiroshima and Nagasaki, respectively. In order to investigate late effects of atomic bomb radiation on humans, 94,000 survivors were selected and registered as cohort members of an epidemiological study, LSS (Life Span Study). On the other hand, comprehensive efforts have been continued to estimate radiation dose to individual survivors. The latest version of the dosimetry system, DS02 (Dosimetry System 2002) was adopted in 2003. Radiation dose at 1 m above the ground in open field at 1 km from the hypocenter was estimated to be 4.5 and 8.7 Gy in Hiroshima and Nagasaki, respectively, while at 2 km it was 0.08 and 0.14 Gy. According to the recent LSS report for the period of 1950-2000, among 86,611 survivors to whom individual dose was estimated, there have been 47,685 deaths (55%), including 10,127 from solid cancer and 296 from leukemia. The statistical analysis of the recent LSS data supports a linear-quadratic dose-response model for solid cancer, while the previous analyses indicated a linear dose-response. A linearquadratic model is suggested for leukemia.

The history of radioecology is described from the end of the XIX - the beginning of the XX centuries till the present days with the indication of the major evolutionary stages of this area of knowledge. The ecological aspects of the use of nuclear power engineering for military purposes (global contamination of the environment after nuclear tests) in the 1960s-1980s are elucidated. The paper also touches upon the ecological problems of nuclear power engineering development. Some issues of the radiation protection of the environment are analysed (anthropocentric and ecocentric principles). The paper summarises the main tasks of radioecology at the present stage. The role is stressed of studying the importance of the elevating radiation background of the environment considering the ever-growing anthropogenic pressure to biota.

This paper discusses the recent moves to protect non-human species as distinct from Man, from the effects of ionizing radiation. The position is put, that much of the concern surrounding low dose exposures is due to irrational fear and is not based on scientific data. If anything the data show protective or negligible effects at low doses not deleterious effects. The paper looks at the consequences of the situation and explores possible reasons for the deep seated fear of radiation which has led to the political need to address what may not be a problem.

In models of radiocapacity for miscellaneous types of ecosystems (slopes, water ecosystems etc.) rather small levels of primary contamination of ecosystems are established, which, due to the laws of reallocating of radionuclides, may result in concentration in biota of critical levels of the contents of radionuclides and formation of noticeable radiation doses. From a number of estimations, dose rates in biota of 0.4 Gy/year for animals and 4 Gy/year for plants can notably oppress growth and condition of biota in ecosystems. If we accept ecological risk arising at these doses, it is possible to define for a unit of biomass, concentrations of radionuclides which are capable of giving similar radiation doses. This give a value for ^137Cs of 100 kBq/kg for animals and 1000 kBq/kg for plants, as an example. Based on a hypothesis about linear increase of ecological risk for biota from 0 up to 1, with increase in the level of radionuclide contamination of ecosystems, the general ecological risk from miscellaneous radionuclides which accumulate in a real ecosystem can be estimated.

The paper gives the data based on the many-year observations over tritium contents in the water ecosystems of Ural region. Almost all tritium in Ural region, including the control plots, was of anthropogenic origin. Nuclear enterprises are the main sources for the environmental contamination which tritium. In the areas where such enterprises are situated technogenic complexes for the retention and localisation of tritium should be developed and constructed.

This paper addresses the issue of multiple stressors in the environment all acting by common mechanisms, to produce a variety of non-targeted effects.