The results of selective cytogenetic monitoring of Chernobyl accident victims in the Ukraine

Selective cytogenetic monitoring of the highest priority groups of Chernobyl disaster victims has been carried out since 1987. In 1992-1993, 125 liquidators (irradiated mainly in 1986) and 42 persons recovering from acute radiation sickness of the second and third degrees of severity were examined. Cytogenetic effects (an elevated level of unstable as well as stable markers of radiation exposure) were found in all groups, which showed a positive correlation with the initial degree of irradiation severity even 6-7 y after the accident. Comparative scoring of conventional staining vs. G-banding in 10 liquidators showed the identical rate of unstable aberrations. At the same time, the yield of stable aberrations for G-banded slides exceeded the frequency for conventional staining. In order to study possible mutagenic activity of chronic low levels of irradiation, the cytogenetic monitoring of some critical groups of the population (especially children and occupational groups-tractor drivers and foresters) living in areas of the Ukraine contaminated by radionuclides was carried out. In all the examined groups, a significant increase in the frequency of aberrant metaphases, chromosome aberrations (both unstable and stable), and chromatid aberrations was observed. Data gathered from groups of children reflect the intensity of mutagenic impact on the studied populations and demonstrate a positive correlation with the duration of exposure. Results of cytogenetic examination of adults confirmed the importance of considering the contribution of occupational radiation exposure to genetic effects of Chernobyl accident factors on the population of contaminated areas. Results of our investigations demonstrated the possibility of evaluating the mutagenic impact of acute and long-term irradiation of different intensities on somatic cells of persons undergoing radiation exposure due to the Chernobyl accident and confirmed the need to introduce new informative genetic methods [especially fluorescence in situ hybridization (FISH)] for reliable retrospective cytogenetic dosimetry of radiation exposure in Chernobyl accident victims.