MUTAGENICITY OF PARTICULATE-EMISSIONS FROM THE M16 RIFLE - VARIATION WITH PARTICLE-SIZE

Emissions generated by firing the M16 rifle with the propellant WC844 in a combustion chamber designed to simulate conditions of actual use were tested for mutagenic activity in the Salmonella/Ames assay. Dimet hyl sulfoxide extracts of emissions collected from either the breech o r muzzle end of the rifle were mutagenic in three strains of Salmonell a (TA1537, TA1538, and TA98) both in the presence and absence of metab olic activation systems (S9). The extracts were negative in strains TA 100 and TA102. Aerosols generated by firing the M16 rifle were fractio nated according to aerodynamic diameter. Submicrometer particles were far more mutagenic than particles with aerodynamic diameters between 1 and 15 mu m. The mutagens associated with the smaller particles were more active in the presence of S9, while extracts of larger particles were as active, or more active, in the absence of S9. Heavier particle s, which settled rapidly out of the airstream, were not mutagenic.