An increased frequency of structural chromosome aberrations in persons present in the vicinity of Chernobyl during and after the reactor accident. Is this effect caused by radiation exposure?

About a week after the reactor accident in Chernobyl, a number of German citizens returned to the Federal Republic of Germany from different places of residence in the U.S.S.R. Chromosome analyses of these individuals show a surprisingly significant increase in dicentric chromosomes in comparison to the laboratory control. Acentrics are nearly twice as frequent as dicentrics. Centric rings are also in evidence. Chromatid breaks do not significantly differ from the control with the exception of 1 place of residence. The frequency of aberrations is too high to be induced by absorbed doses calculated physically or by modelling techniques. So far, no explanation is available for the discrepancy-a factor of about 100-between calculated absorbed doses and the measured biological effect.