Cytogenetic biomonitoring carried out in a village (Dolon) adjacent to theSemipalatinsk nuclear weapon test site

The Semipalatinsk region (Kazakhstan Republic) has been affected by extensi ve radioactive contamination due to more than 450 nuclear tests of which al most 100 were exploded in the atmosphere. The present results refer to cyto genetic assessments in a study cohort of the population of Dolon, a settlem ent located on the NE boundary of the nuclear weapon test site, which was e xposed to elevated doses of ionising radiation primarily due to the first S oviet nuclear test in 1949. Conventional cytogenetic analyses were carried out on 21 blood samples from individuals (more than 50 years old) living in Dolon since the very beginning of nuclear testing. A matched control group included 20 individuals living in non-contaminated areas. Higher frequenci es of chromosome aberrations were found in the Dolon cohort compared to the control group, even though they remain within the range of the background levels reported for large normal human population studies on elderly indivi duals.