A follow-up cytogenetic study of workers highly exposed inside the Chernobyl sarcophagus

Data are presented on some of the engineers and scientists who regularly entered highly radioactive areas of the sarcophagus chamber constructed around the ruins of the Chernobyl reactor. Previous investigations on six of them by unstable chromosomal aberrations, quartz fibre electrometers and, in some cases, tooth electron spin resonance have all indicated high doses accumulated over several years of work inside the sarcophagus. Here, the authors present the data on eleven of the men who agreed to be monitored cytogenetically although two have since died aged 45 and 66 y. The present data were combined with the previous to examine the time-courses of these individuals' changes in their aberration frequencies. As expected, dicentric aberrations showed a clear drop down to 2-3 per 100 cells since the men ceased working inside the sarcophagus. In contrast, the translocation yields remained at a high level showing no tendency to decrease and so proved reliable for retrospective biodosimetry. These data are particularly useful in demonstrating the value of FISH long after high but protracted and fractionated exposure.