Cytogenetic damage in lymphocytes of healthy and thyroid tumor-affected children from the Gomel region (Belarus).

During 1994, 19 thyroid tumor-affected children and 17 healthy children from the Gomel region, one of the areas most polluted by the Chernobyl fallout, were analysed for (i) the presence of 137Cs in their urine and (ii) chromosome aberrations (CA) in circulating lymphocytes. They were compared with 35 healthy children from Pisa, Italy. Tumor-affected children showed significantly (p < 0.05) higher 137Cs levels in their urine as compared to healthy controls from the Gomel region. No radioactivity was found in urine from the Pisa controls. CA frequency was significantly higher in tumor-affected children compared to the Gomel controls, but was not significantly different between Gomel and Pisa controls. However, dicentric chromosomes were found in a significantly (p < 0.01) greater proportion in both affected and healthy Gomel children (3.4 and cells, respectively) as compared to the Pisa controls ( cells). Multiple regression analysis showed that the proportion of cells with acentric fragments, dicentric and ring chromosomes was significantly correlated (p < 0.05) with the amount of 137Cs excreted in their urine. These findings suggest that children from the Gomel region were still being exposed to radionuclides, which makes it possible to study a dose-effect relationship.