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Health Effects of Soy-Biodiesel Emissions: Mutagenicity-Emission Factors
Citation:
Mutlu, E., S. Warren, P. Matthews, C. King, L. Walsh, A. Kligerman, Judy Schmid, D. Janek, I. Kooter, Bill Linak, Ian Gilmour, AND D. DeMarini. Health Effects of Soy-Biodiesel Emissions: Mutagenicity-Emission Factors. INHALATION TOXICOLOGY. Informa Healthcare USA, New York, NY, 27(11):585-596, (2015).
Impact/Purpose:
Soy biodiesel is the primary form of biodiesel available commercially in the U.S., but limited studies exist about the health safety of the emission from such a fuel. We showed that as the percentage of soy oil increased in the fuel, the lower the mutagenicity of the emissions. Our chemical analysis showed that this was due to a reduction in the concentration of polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs, and presumptively nitro-PAHs and aromatic amines. These results indicate that the emissions from soy biodiesel are less hazardous than those from petroleum diesel.
Description:
Soy biodiesel is the predominant biodiesel fuel used in the U.S., but only a few, frequently conflicting studies have examined the potential health effects of its emissions.OBJECTIVE: We combusted petroleum diesel (B0) and fuels composed of increasing percentages of soy methyl esters (B20, B50, and B100) and determined the mutagenicity-emission factors expressed as revertants/megajoule thermal (rev/MJth).METHODS: We combusted each fuel in replicate in a diesel engine without emission controls at a constant load, extracted organics from the particles with dichloromethane, determined the percentage of extractable organic material (EOM), and evaluated these concentrates for mutagenicity in 16 strains/S9 combinations of Salmonella. RESULTS: The mutagenic potencies of the EOM were not significantly different between replicate burns for B0 and B100 but were for B20 and B50. B0 had the highest rev/MJth, and those of B20 and B100 were 50% and ~85% lower, respectively, in strains that detect mutagenicity due to polycyclic aromatic hydrocarbons (PAHs), nitroarenes, aromatic amines, or oxidative mutagens. For all strains, the rev/MJth decreased with increasing soy in the fuel. There were modest correlations (r2 = 0.3 to 0.5) between the concentrations in the emissions of specific classes of PAHs and the mutagenicity of the emissions in strains that detect those chemical classes. CONCLUSIONS: Under a constant load, soy-biodiesel emissions were 50-85% less mutagenic than those of petroleum diesel; however, without emission controls, all the fuels had high mutagenicity-emission factors that were within the range of typical uncontrolled combustion, such as that from a residential wood-burning fireplace.
