EVIDENCE FOR A NEW CLASS OF MUTAGENS IN DIESEL PARTICULATE EXTRACTS

Particles from the exhaust of diesel-powdered vehicles are of concern because these particles contain carcinogenic compounds. Organic solvent extracts of these particles are mutagenic in the Ames assay using strains TA98 and TA100. We wanted to know whether TA102, a strain that is sensitive to oxidative mutagens, could detect these types of compounds in methylene chloride extracts of diesel particles. Approximately 47 % of the mutagenicity applied to the column was recovered. The mutagenicities of several selected mono- and dinitroarenes were markedly reduced in TA102 compared to their mutagenicities in TA98. The concentrations of selected nitroarenes were estimated using selected-ion GC-MS. The contribution of mono- and dinitroarenes to the total TA102 mutagenicity of this diesel particle extract is less than 1 % of the total mutagenicity applied to the column. Our results suggest that strain TA102 is detecting a new class of compounds in diesel particle extracts that can oxidize DNA.