Abstract: For the purpose of elucidating the genotoxic dose and genotoxicity characteristics of selenium , healthy human peripheral blood lymphocytes (PBL) in vit ro were t reated for 72h by supplementing with different doses of sodium selenite , then the changes of the f requrncies of sister2chromatid exchanges (SCE) and chromosome aberrations were observed. The result s showed that when the culture of PBL was supplemented with sodium selenite at 0. 05mg/ L and 0. 25mg/ L , the f requencies of SCE and chromosome aberrations were not significantly increased ( P > 0. 5 and P > 0. 3 respectively) , when at 0. 75mg/ L and 1. 50mg/ L , the f requencies of SCE and chromosome aberration were increased obviously ( P < 0. 01 and P < 0. 001 respectively) . High doses of sodium selenite could cause chromosome deform and cent romere segregate premat ruely. It is suggested that high dose selenium possesses mutagenic effect and might possess many other cytotoxinic effects.

Key words: sodium selenite, sister2chromatid exchange, chromosome aberration