BIOASSAY-DIRECTED CHEMICAL-ANALYSIS OF LOS-ANGELES AIRBORNE PARTICULATE MATTER USING A HUMAN CELL MUTAGENICITY ASSAY

The human cell mutagenicity of Los Angeles airborne fine particulate m atter is examined via bioassay-directed chemical analysis. A 1993 comp osite fine particle sample is separated via liquid chromatography into fractions containing organic compounds of varying polarity. Samples a re analyzed by the h1A1v2 human cell mutagenicity assay to identify th ose fractions that contain human cell mutagens and by GC/MS to identif y the chemical character of those mutagens. Those subfractions that co ntain unsubstituted polycyclic aromatic compounds (PAC) are responsibl e for a considerable portion of the mutagenic potency of the whole atm ospheric sample. Six unsubstituted PAC (cyclopenta[cd]pyrene, benzo[a] pyrene, benzo[ghi]perylene, benzo[b]fluoranthene, indeno[1,2,3-cd]pyre ne, and benzo[k]fluoranthene) account for most of the mutagenic potenc y that can be assigned to specific compounds within the atmospheric sa mples. Important semipolar mutagens that are quantified include 2-nitr ofluoranthene and 6H-benzo[cd]pyren-6-one. A large number of other aro matic organics are identified as candidates for future testing as pure compounds in the human cell assay, at which time it should be possibl e to account for more of the mutagenic potency of the atmospheric samp les.