1-NITROPYRENE AS A MARKER FOR THE MUTAGENICITY OF DIESEL EXHAUST-DERIVED PARTICULATE MATTER IN WORKPLACE ATMOSPHERES

The use of 1-nitropyrene (1-NP) as a marker for the occupational expos ure to diesel exhaust (DE) mutagens was investigated in workplace atmo spheres contaminated with DE from a variety of emission sources, such as power supplies, forklifts, trucks, caterpillar vehicles, trains, sh ips' engines, and vehicles in city traffic. Total suspended particulat e matter was collected by area sampling. The 1-NP content of acetone e xtracts of these samples as determined by gas chromatography-high reso lution mass spectrometry varied from 0.080 to 17 mu g/g acetone extrac table matter, corresponding to air concentrations of 0.012 to 1.2 ng/m (3). A sample collected in a rural area contained 0.0017 ng/m(3) 1-NP. The mutagenicity of the extracts was tested in the Salmonella typhimu rium strains TA98 and TA1538, using the microsuspension assay with and without metabolic activation by an exogeneous metabolizing system (ra t liver S9-fraction). In addition, the S. typhimurium strains YG1021 a nd YG1024 were used because of their high sensitivity towards the muta genicity of nitro polycyclic aromatic hydrocarbons. When plotting the mutagenic potency of the air sample extracts as determined in the abse nce of liver S9 versus the particle-associated 1-NP level, a relativel y high correlation (r = 0.80-0.91) was observed in all of the S. typhi murium strains. High correlations (r = 0.80-0.93) were also observed w hen plotting the results of mutagenicity testing after activation by S 9 versus the outcome of chemical analysis. These results show that the 1-NP content of workplace air samples is associated with their mutage nic potency, suggesting that 1-NP may be used as a marker for occupati onal exposure to DE-derived particle-associated mutagens. (C) 1995 Wil ey-Liss, Inc.