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Analyses of extracted biodiesel and petroleum diesel exhaust particle and the effects on endothelial cell toxicity and antioxidant response.
Citation:
Bhavaraju, L., J. Pleil, T. M. KORMOS, M. C. MADDEN, AND U. P. KODAVANTI. Analyses of extracted biodiesel and petroleum diesel exhaust particle and the effects on endothelial cell toxicity and antioxidant response. Presented at Society of Toxicology (SOT) Annual Meeting, San Francisco, CA, March 11 - 15, 2012.
Impact/Purpose:
Using soy based BD exhaust we analyzed organic extracts (hexane, methanol, DMSO) of the BD PM for evidence of unique combustion components.
Description:
Biodiesel (BD) is a renewable energy source and is readily substituted in diesel engines. Combustion of biodiesel is cleaner due to the efficiency of the fuel to completely combust. Biodiesel combustion emissions contain less CO, PAHs, aldehydes, and particulate matter (PM) mass relative to petroleum diesel (PD) emissions. BD is typically used commercially as a blend for use in on-road diesel engines, commonly as 20% BD (balance PD) (B20). Using soy based BD exhaust we analyzed organic extracts (hexane, methanol, DMSO) of the BD PM for evidence of unique combustion components. We have identified by HPLC-PDA B20 PM extract to contain more non-polarcomponents than pure BD(B100). Further analysis of the PM provides details on the presence of fatty acids in particle extract. Longer carbon chain fatty acids are present in the B20 and shorter carbon chains are detectable in the 100% PD (BO) extract. Aldehydes were identified in the BO, B20 and B100 PM. Because PD emissions can induce vascular endothelial cell dysfunction, the cytotoxicity of the extracts was examined using LDH activity release from, and trypan blue dye uptake into, an EA hy96 endothelial cell line exposed for 6 hr to 0-400 ug/ml PM extract-equivalents. The data suggested B100 is more toxic than the B20 and the BO extracts in a dose dependent manner. Gene expression of the antioxidants SOD-l and heme oxygenase-l (HO-l) were examined relative to vehicle control exposed cells. BO (10ug/ml), B20 (200 ug/ml), and B100 (300 ug/ml) exposure induced maximal HO-l expression increases of 2.8-, 3.2-, 3.9-fold, respectively. SOD-l gene expression increased 2.0-fold with BO exposure (100 ug/ml), but no increases were observed with the other extracts. The current data suggests both BD and PD extracts induce alterations in endothelial cell antioxidant responses. [This is an abstract of a proposed presentation and may not necessarily reflect official US EPA Policy.]