[en] According to data established in 1996, the frequencies of micronucleated erythrocytes in bone marrow and peripheral blood of bank vole (Clethrionomys glareolus, Schreber), whose populations have been lived in contaminated areas since 1986 depend on chronic low intensity irradiation (dose rates in the range from 2,4 to 41,3 mGy/day). The forms of these dose-effect relationships for the observed cytogenetic injuries are nonlinear and better described by the parabola equations. It is found that inducible repair system 'adaptive response' functions quite well within 21st-24th bank vole generations after the Chernobyl accident