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BIOASSAY-DIRECTED FRACTIONAL AND SALMONELLA MUTAGENICITY OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES
Citation:
DeMarini, D M., L R. Brooks, S H. Warren, T. Kobayashi, M I. Gilmour, AND P. Singh. BIOASSAY-DIRECTED FRACTIONAL AND SALMONELLA MUTAGENICITY OF AUTOMOBILE AND FORKLIFT DIESEL EXHAUST PARTICLES. ENVIRONMENTAL HEALTH PERSPECTIVES 112(8):814-819, (2004).
Impact/Purpose:
A comprehensive understanding of the mechanisms responsible for the health effects of DEP requires the evaluation of DEP standards for a variety of endpoints, and our results highlight the need for multi-disciplinary studies on a variety of representative samples of DEP
Description:
Abstract
Many pulmonary toxicity studies of diesel exhaust particles (DEP) have used an
automobile-generated sample (A-DEP) whose mutagenicity has not been reported. In contrast,
rnany inutagenicity studies of DEP have used a forklift-generated sample (SRM 2975) that has been evaluated in only a few pulmonary toxicity studies. Thus, we evaluated the mutagenicity of both DEP in Saimonelia coupled to a bioassay-directed fractionation. The percent extractable organic material (EOM) was 26.3% for A-DEP and 2% for SRM 2975. Most of the A-EOM
(-55%) eluted in the hexane fraction, reflecting the presence of alkanes and alkenes, typical of
uncombusted fuel. In contrast, most of the SRM 2975 EOM (-58%) eluted in the polar methanol
fraction, indicative of oxygenated and/or nitrated organics derived from combustion. Most of the
direct-acting, base-substitution activity of the A-EOM eluted in the hexane/dichloromethane
(DCM) fraction, but this activity eluted in the polar methanol fraction for the SRM 2975 EOM.
The direct-acting frameshift mutagenicity eluted across fractions of A-EOM, whereas >80% eluted only in the DCM fraction of SRM 2975 EOM. The A-DEP were more mutagenic than SRM 2975 per mass of particle, having 227X more PAH-type and 8-45X more nitroarene-type mutagenic activity. These differences were associated with the different conditions under which the two DEP samples were generated and collected. A comprehensive understanding of the mechanisms responsible for the health effects of DEP requires the evaluation of DEP standards for a variety of endpoints, and our results highlight the need for multi-disciplinary studies on a variety of representative samples of DEP.
This abstract does not necessarily reflect the policy of US EPA
