Radioadaptation of rodents in the zone of local radioactive contamination (Kyshtim Accident, Russia): 50 years on

Abstract

Abstract.Results of radioecological investigations of rodents having different ecological specializationwood and field mice, northern red-backed voles and mole-voles to acute (laboratory experiment) and chronic (long-term inhabiting the East Ural Radioactive Trace -EURT) irradiation are summarized. These species are greatly distinguished by a way of life, a migratory activity, an average life span etc. Numerous immunological, hematological and cytogenetical disturbances were found in more radioresistant wood and field mice and northern red-backed voles inhabiting the EURT zone (density of soil pollution by 90 Sr − 18.5 MBq/m 2 = 500 Ci/km 2 ) as compared with the reference samples. On the contrary there were no pathological shifts in more radiosensitive mole-voles from the more radioactively contaminated site ( 90 Sr − 37 MBq/m 2 = 1000 Ci/km 2 ). The absorbed dozes during the life for the mole-voles from the EURT zone were significantly higher (in 30 times) than these ones for mice and voles. These data testify about the possibility of radioadaptation in a series of generations in mole-voles that developed due to their ecophysiological features and isolation of settlement in the radiocontaminated zone. Mice and voles form a flowing population and slip off the prolonged influence of a damaging factor, this circumstance prevents the development of radioadaptation.

East urals radioactive trace: Adaptive strategy of rodents’ population

“…However, the possibility of radioadaptation in a series of generations that developed due to ecophysiological features (subterranean borrowing way of life, quite low migratory activity) and isolation of settlement in the EURT zone (since 1957) was shown in mole-voles (Ellobius talpinus) [13,14]. But mice and voles form a flowing population and slip off the prolonged influence of a damaging factor, this circumstance prevents the development of radioadaptation [3]. Multigenerational effects induced by chronic external and internal irradiation by 137 Cs (direct effects, transgeneration transmission of radiation-induced damages, radioadaptive effects) have been observed in natural bank vole (Clethrionomys glareolus) population inhabiting in the Chernobyl zone [15].…”

“…This approach supposes to divide natural population into groups of individuals with the same functional status, i. e. with the uniform patterns of growth and/or maturation rate as well as whether they participate in reproduction (scheme of two alternative pathways of mouse-like rodents' ontogenetic development presented early [3]. Individuals of different types of ontogeny (functional status) manifest significantly diverse radioresistance [5].…”

“…Because of this rodents of mobile species (mice and voles) are able to pass through significant distances that are comparable with the cross-section size of EURT area. This leads to forming of a flowing population [3], i. e. a population with constantly changing set of individuals due to immigrants from adjacent unpolluted areas and emigrants from the polluted zone. The main dose load radionuclide in the EURT zone is 90 Sr (95%), which accumulates in the skeleton of vertebra and irradiates organs and tissues during the all life of animal.…”

Assessment of radiation exposure of murine rodents at the EURT territories

“…These animals have demonstrated the activation of immune system, completeness of immune response to infection. Effects such as increase in the frequency of aberrant cells, pathological changes and suppression of both immune and hematopoietic systems were not seen [10,12,17,18]. Lyubashevskiy et al [18] have concluded that EURT mole vole have developed perfect adaptation to the surrounding radiation.…”

“…Estimates of doses and effects of irradiation on plants are presented in [3,4]. Among other animals, the murine rodents are the most studied [5][6][7][8][9][10][11][12][13][14][15][16].…”