The investigation was concerned with the influence of smoking on manganese (Mn), lead (Pb) and cadmium (Cd) content in the blood of metropolitan groups of varying age as well as on genotoxic reactions in leukocytes after test irradiation ex vivo. The study involved 325 inhabitants of St.Petersburg, aged 10-90 years. Venous blood was assayed for metal ecotoxicant content using standard AAS-flame method and DNA leukocyte decay following test irradiation (2Gy) ex vivo. Aging was shown to involve a sequence of consistently rising metal levels: Cd - Mn Pb. Relative accumulation of Pb was greater in males while that of Mn - in females. The rates of Cd, Mn, Pb accumulation in smokers were higher than in non-smokers. Smoking promoted genotoxic response to testing exposure which induced Cd-related disturbances of DHA repair system in males. Among smoking females, risk of adverse effects rose as a result of concurrent action of the genotoxic factor. It was also evident among female non-smokers when radiation was used in conjunction with enhanced concentrations of Mn and Cd. Hence, correlations between smoking and Cd, Mn, Pb accumulation, on the one hand, and Cd-related accumulation and enhanced genotoxic response in leukocytes, on the other, were established. It is likely that carcinogenic risk of tobacco smoking should be accounted for by both mere presence of a carcinogenic agent and its potential to promote Cd level thus inhibiting withdrawal of carcinogenic DNA adducts from the cellular genome.