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A COMPARATIVE ASSESSMENT OF BOISE, IDAHO, AMBIENT AIR FINE PARTICLE SAMPLES USING THE PLATE AND MICROSUSPENSION SALMONELLA MUTAGENICITY ASSAYS
Citation:
Claxton, L D., S. H. Warren, R B. Zweidinger, AND J P. Creason. A COMPARATIVE ASSESSMENT OF BOISE, IDAHO, AMBIENT AIR FINE PARTICLE SAMPLES USING THE PLATE AND MICROSUSPENSION SALMONELLA MUTAGENICITY ASSAYS. SCIENCE OF THE TOTAL ENVIRONMENT 275(1-3):95-108, (2000).
Description:
The primary objective of this study is to characterize the genotoxic potential of the ambient air aerosols collected within an air shed impacted primarily by wood smoke and automotive emissions. The study also examines the relative merits of a microsuspension assay and the standard plate assay for monitoring the presence of airborne particle-bound mutagens.
Wintertime ambient air particulate samples collected from Boise, Idaho, USA, were shown to contain extractable organic matter that is mutagenic in the Salmonella typhimurium microsuspension and plate-incorporation assays. Within this study, mutagenicity of the background site samples could account for 7 to 34 percent of the total airborne mutagenicity of the urban sites. Differences in the results from the primary sites, auxiliary sites, and the background site demonstrate that the particle-bound mutagens are not evenly distributed within the air shed and are more associated with the location of sampling than with the .time of sampling or the type of bioassay used to evaluate the samples. This study also demonstrates tllat the bioassay protocol used in such studies should depend upon the characteristics of the air shed's mutagens and the purpose of the study. For example, the microsuspension assay gave somewhat more variable results but was approximately threefold more sensitive than the plate assay. When strain T A98 was used in the microsuspension assay, the mutagenic response was greater without an exogenous activation system. The reverse was true for the plate assay in which the use of an exogenous activation system increased the mutagenicity response. TAl 00 in the microsuspension assay provided results comparable to those with T A98. This is important because TAlOO can also be used to bioassay semivolatile and volatile organics associated with ambient air mutagenicity. This, in turn, allows a comparison of the mutagenicity of organics collected by differing methods due to their volatility .Future studies should be directed toward correlation of mutagenicity results with other analytical results in order to further develop methods for better characterization of the genotoxicity of ambient air .
Key words: Boise, Idaho; air quality; airborne particles; particle-bound mutagens, wood smoke, mobile sources, automotive emissions, PM-2.5
This abstract does not necessarily reflect th US EPA policy.