Quantitative integration of the Salmonella microsuspension assay with supercritical fluid extraction of model airborne vapor-phase mutagens.
Vapor-phase mutagens are potentially a major class of toxic contaminants in ambient and indoor air. These compounds are not routinely analyzed due to a lack of an established integrated methodology to quantitatively trap, extract and test the compounds in a bioassay. In a previous report, we emphasized the trapping of volatile and semi-volatile mutagens and the extraction of these compounds using supercritical carbon dioxide (CO2). In the present study, we discuss the use of a bioassay for the quantitation of the model mutagens, ethylene dibromide(EDB) and 4-nitrobiphenyl (4-NB), trapped from an airstream. The compounds EDB and 4-NB were released into a controlled airstream, trapped on XAD-4 adsorbent, and were extracted using supercritical CO2. The extract was tested in a microsuspension modification of the Ames Salmonella/microsome test adapted for volatile compounds. Linear dose-response relationships were obtained for supercritical CO2-extracted EDB using tester strain TA100 (+/- S9) and for 4-NB using tester strains TA98 and TA100 (-S9). Standard dose-response curves with known amounts of the compounds were also determined for comparison with measured amounts of the model compounds collected in an airstream. The gas chromatographic (GC)- and bioassay-determined quantities of EDB and 4-NB were highly correlated, accurate and precise. For example, bioassay-determined EDB concentrations were within 10% of the GC-determined concentrations. Our results demonstrate that the integrated methodology for vapor-phase mutagens developed in this study would be useful for quantitative analysis of these and related airborne vapor-phase mutagenic compounds.
Kado
N Y
NY
Department of Environmental Toxicology, University of California, Davis 95616.
Wong
J M
JM
Kuzmicky
P A
PA
Woodrow
J E
JE
Ning
H
H
Seiber
J N
JN
Hsieh
D P
DP
D001713:Biphenyl Compounds / Q000032:analysis*; D002849:Chromatography, Gas; D002853:Chromatography, Liquid; D015946:Ethylene Dibromide / Q000032:analysis*; D005798:Genes, Bacterial; D009152:Mutagenicity Tests; D009153:Mutagens / Q000032:analysis*; D012475:Salmonella / Q000187:drug effects; D014835:Volatilization
D001713:Biphenyl Compounds; D009153:Mutagens; D015946:Ethylene Dibromide; C040438:4-nitrobiphenyl