Determining the mutagenic activity of a tar, its vapors and aerosols.

The Ames test was performed on Salmonella typhimurium, strain TA98, TA100, TA1535, TA1537, TA1538, to evaluate the mutagenic potential of a tar as well as its vapors and aerosols emitted at 250, 350 and 550 degrees C. Two chemical procedures were used: extractions of aromatics for DMSO; elimination of acids, alcohols and phenols. Weak mutagenic activity was demonstrated at each temperature. Then, using only Salmonella typhimurium strains TA98 and TA100, a study was made on the effects of the mutagenic compounds, benzo[a]pyrene, 2-aminoanthracene, nitrofluorene, methyl methanesulfonate and on the vapors and aerosols emitted at 350 degrees C by road-coating tar. For promutagenic compounds, an enhancing effect was observed before an inhibition effect. For direct mutagenic compounds, only the inhibition effect appeared. The mutagenic and/or carcinogenic activity was usually tested on a pure isolated chemical compound.