MUTAGENICITY OF SCOOTER EXHAUST PARTICULATE MATTER

By using the in vitro Ames Salmonella/microsomal assay and the in vivo mouse micronucleus assay, studies were performed to evaluate the geno toxicity of gasoline exhaust particulate matter generated from five di fferent domestic and imported scooters. In the Ames assay, treatment o f test strains TA98 and TA100 with solvent extracts of particulate mat ter from four of five scooter models caused an increase in the number of histidine-independent colonies over the background in TA98 without S9 mix. Positive results were also obtained from the micronucleus assa y. The frequencies of bone marrow micronucleated polychromatic erythro cytes were significantly higher in the treated compared to the nontrea ted animals, and the increases in the frequencies were not significant ly different among the five types of scooters. Analyses of chemical co mponents showed that scooter exhaust particulate matter contained more than 100 different substances including polycyclic aromatic hydrocarb ons.