The mutagenicity of cigarette smokers' urine.

Using the methods of Yamasaki and Ames (1977), we have studied the mutagenicity of urine samples from 29 cigarette smokers and 14 nonsmokers. Duplicate plates at each dose yield reproducible dose-response curves, evening and 24-hour samples of smokers' urine have similar levels of mutagenic activity, as do evening samples from the same smoker from different days. Smokers' daily cigarette tar intake is correlated with urinary mutagen concentration, but the correlation achieves statistical significance only in the sub-sample of smokers over 25 years old. Mutagenic activity is also detectable in some nonsmokers, but as a group, their urinary mutagenic activity is far lower than that of smokers.