Abstract
From 1949 to 1989, the former USSR conducted more than 450 nuclear explosion tests, including/ atomospheric and underground tests, at Semipalatinsk nuclear test site. The significant activity remaining includes long lived radioisotopes of Pu, Cs and Sr. Radioactive clouds moved on villages at the time of every nuclear test also emitted external radiation. Therefore, individuals lived near nuclear test site are considered to had been influenced by both internal and external exposures. In order to assess the prolonged radiation effects on individuals, chromosome analysis was performed in lymphocytes from 86 peoples living three villages, Dolon, Sarajar and Kaynar, where are from 80-150 km away from nuclear test site, and 25 control peoples in Kocpecti, being away from 700 km. Micronucleus assay was also done in 184 peoples in five different contaminated villages and one control village. Frequencies of dicentric and ring chromosomes in peoples at contaminated area(0.36-0.45 per 100 cells) were higher than those at non-contaminated area (0.12 per 100 cells). Peoples in the four villages had multiple complex chromosome aberrations(MCA) in 0.12-0.42%, with unknown reason. Micronucleus incidences in exposed group (9.36-12.3 per 1,000 lymphocytes) were also higher than non-exposed group(8.11 per 1,000 lymphocytes). Higher incidence of unstable type aberrations such as dicentric, ring chromosomes and micronucleus found in residents at contaminated areas seem to be mainly caused by internal exposure. Also, 1.2% of translocations were detected by FISH method.
