Exposure to carcinogenic chemicals and smoking increases urinary excretion of mutagens in humans.

Urine samples from a control population and from a population of chemical workers from two chemical plants near Florence, Italy, were analyzed for the presence of mutagenic chemicals by the Salmonella/microsome test. When tested with strain TA1538, the urine of nonsmoking chemical workers showed higher mutagenic activity than that of controls in the presence of in vitro metabolic activation, but no difference was found between controls and chemical workers who both smoked. Increased mutagenic activity was observed in the group of control smokers compared to control nonsmokers, but the same effect was not observed for chemical workers. When TA100 was used as the tester strain, the chemical workers, both smoking and nonsmoking, had significantly higher mutagenic activity than controls. The mutagenic activity fell to control levels in some workers' urine after 20 d leave. Although some perturbing effects of smoking habits were observed, the results seemed to indicate the usefulness of the Salmonella/microsome test for detection of mutagens in human urine. The results also suggest that people exposed to potentially carcinogenic chemicals may show high enough traces of those chemicals and/or their metabolites in their body fluids to be detected with current mutagenesis techniques.