Chromosomal aberrations in lymphocytes of residents of areas contaminated by radioactive discharges from the Chernobyl accident

Approximately 5 years after the Chernobyl accident blood samples were collected and analysed for unstable chromesomal aberrations in lymphocytes from persons who have lived continuously in contaminated areas of Belarus and Russia. Including controls, 1855 persons were studied. The majority of subjects comprised 10 cohorts of children including one control group and one group who were initially exposed at a high dose rate prior to their evacuation to a lightly contaminated area. One control and two exposed cohorts of adults were also examined. The mean yields of chromosomal aberrations in the exposed subjects were generally above those of the controls, although statistical significance was observed in only the evacuee children and in children and adults permanently resident in one community where the average environmental contamination with ¹³⁷Cs was approximately 1000 kBq.m^-2. The average dose in excess of background to subjects in this community, received over 5 years, was tentatively estimated from the chromosomal damage and the radionuclide contamination to be approximately 100 mGy. One cohort of children was especially selected to include a number of subjects who have received in utero exposure. There was no significant difference found in the level of induced aberrations in these children's lymphocytes compared with those exposed only post-natally.