Tobacco specific N-nitrosamines: occurrence and bioassays.

A new GC-TEA method for the analysis of tobacco-specific N-nitrosamines (TSNA) has been developed. Four TSNA have thus far been identified; these are N'-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N'-nitrosoanatabine (NAT) and N'-nitrosoanabasine (NAB). The method is currently being applied to the development of cigarette filter-tips which will selectively remove these carcinogens from cigarette smoke. Since recent epidemiological studies have established a correlation between snuff dipping and oral cancer, we have analysed leading snuff brands for TSNA. Snuff products from Sweden, Denmark, Bavaria and the USA contained 5-106 mg/kg of the TSNA and the saliva of snuff dippers had TSNA levels of 20-890 micrograms/kg. NNN, NNK and NAB induce benign and malignant tumours of the respiratory tract of mice and rats. We have shown that NNN and NNK induce tumours in the upper respiratory tract of hamsters and that NNK is the most active carcinogen of the TSNA, also inducing adenoma and adenocarcinoma in the hamster lung. The reported chemical analyses and bioassay results support the epidemiological findings on the causal association of tobacco use and cancer in man.