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USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS
Citation:
DeMarini, D M. USE OF BIOASSAY-DIRECTED CHEMICAL ANALYSIS FOR IDENTIFYING MUTAGENIC COMPOUNDS IN URBAN AIR AND COMBUSTION EMISSIONS. Presented at American Organization of Analytical Chemists, St. Louis, MO, Sept. 22, 2004.
Description:
Bioassay-directed chemical analysis fractionation has been used for 30 years to identify mutagenic classes of compounds in complex mixtures. Most studies have used the Salmonella (Ames) mutagenicity assay, and we have recently applied this methodology to two standard reference samples of diesel exhaust particles, one from a fork-lift truck and the other from an automobile. The mass distribution and mutagenicity results were dramatically different, with 55% of the mass of the automobile sample eluting in the hexane fraction, reflecting the presence of alkanes and alkenes. However, 58% of the mass of the fork-lift sample eluted in the polar methanol fraction, indicative of oxygenated and/or nitrated organics. Most of the direct-acting base-substitution mutagenicity of the automobile sample eluted in the hexane/dichloromethane fraction, whereas >80% of this activity of the fork-lift sample eluted in the dichloromethane fraction. We have performed similar studies on incinerator emissions and urban air samples. We have extended these traditional bioassay-directed analyses by analyzing the Salmonella mutants genetically to identify the types of mutations (mutation spectra) induced by the various chemical fractions. Based on these analyses, we have found that the mutation spectra of a complex mixture reflects the dominance of one or two chemical classes within the mixture. These chemical classes are polycyclic aromatic hydrocarbons (PAHs) in urban air, nitroarenes in municipal waste incinerator emissions, PAHs and aromatic amines in cigarette smoke, and PAHs and nitroarenes in diesel exhaust. [Abstract does not necessarily reflect the policy of the US EPA.]