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Mutagenicity Of Emissions From Petroleum Diesel And Biodiesel: Mechanistic Insights From Bioassay-Directed Chemical Fractionation
Citation:
DeMarini, D. Mutagenicity Of Emissions From Petroleum Diesel And Biodiesel: Mechanistic Insights From Bioassay-Directed Chemical Fractionation. Environmental Mutagenesis and Genomics Society, San Antonio, TX, September 22 - 26, 2018.
Impact/Purpose:
This is an abstract of a 30-min invited talk in a symposium on the health effects of diesel exhaust for the annual meeting of the Environmental Mutagenesis and Genomics Society (EMGS), which will be held 22-26 September 2018 in San Antonio, TX. The symposium will present talks on the lung cancer and cardiovascular diseases associated with diesel exhaust exposure. This abstract reviews the IARC monograph on diesel exhaust, specifically on the mechanistic (largely genotoxic) effects of diesel exhaust. The purpose of the symposium is to summarize the main health effects of diesel exhaust.
Description:
The mutagenicity of diesel exhaust was first reported 40 years ago in 1978 by Joellen Lewtas, Larry Claxton, and colleagues at the US EPA. Sufficient epidemiology, rodent cancer, and mechanistic data accumulated by 2014 to enable IARC to evaluate diesel exhaust as a Group 1 (known) human lung carcinogen. This presentation reviews the main mechanistic evidence that supported that evaluation (largely genotoxicity data) as well as new data published since then on the mutagenicity of petroleum and biodiesel exhaust involving bioassay-directed chemical fractionation. Diesel exhaust particulate matter (PM) contains polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, and aromatic amines that play major roles in the mutagenicity of the emissions from both petroleum diesel and biodiesel. The gas phase contains a variety of volatile organics, including aldehydes, butadienes, benzene, acrolein, and oxides of ethylene and propylene that also play such a role. In humans, diesel exhaust increased expression of genes involved in oxidative stress and inflammation, and induced DNA damage (adducts and strand breaks) and micronuclei. In rodents and cells in vitro, diesel exhaust, diesel exhaust PM, and/or organic extracts of the PM induced DNA damage, chromosome aberrations, aneuploidy, gene mutations, apoptosis, and altered gene expression. Oxidation catalysts increased the genotoxicity of the emissions expressed as mutants/mass of PM but decreased the genotoxicity when expressed as an emission factor (mutants/megajoule). In general, mutagenicity emission factors for soy-, canola (rapeseed)-, or used vegetable oil-based biodiesel fuels were 30-80% less than those of petroleum diesel. [Abstract does not reflect policies of the US EPA.]