CYTOGENETIC STUDY IN LYMPHOCYTES FROM CHILDREN EXPOSED TO IONIZING-RADIATION AFTER THE CHERNOBYL ACCIDENT

The present study concerns the monitoring of children from the Byeloru ssian, Ukrainian and Russian republics exposed to the fall-out of the Chernobyl accident. Cytogenetic analyses have been performed on 41 chi ldren coming from different areas and exhibiting varying amounts of Cs -137 internal contamination, as evaluated by whole-body counter (WBC) analysis. On a total of 28670 metaphases scored, radiation-induced chr omosome damage is still present, although at a very low frequency. Due to the very low fraction of dicentrics, because of the time elapsed f rom the accident and the relatively low doses of exposure, radiobiolog ical dosimetry is not possible for these children. However, considerin g that the WBC data indicate that the children are still exposed to Cs -137 contamination, the observed occurrence of stable chromosome rearr angements and breaks may represent the persisting effect of continuous low doses of radiation. The present study also indicates that the par allel use of internal contamination dosimetry and cytogenetics could b e usefully employed to monitor individual exposure to radiation and to define further management measures.