You are here:
Health Effects of Soy-Biodiesel Emissions: Bioassay-Directed Fractionation for Mutagenicity*
Citation:
Mutlu, E., S. Warren, P. Matthews, Judy Schmid, I. Kooter, Bill Linak, Ian Gilmour, AND D. DeMarini. Health Effects of Soy-Biodiesel Emissions: Bioassay-Directed Fractionation for Mutagenicity*. INHALATION TOXICOLOGY. Informa Healthcare USA, New York, NY, 27(11):597-612, (2015).
Impact/Purpose:
This study provides the first detail analysis of the emissions from a range of soy biodiesel fuels. The data show that increasing the percentage of soy in the fuel results in a consistent reduction in the mutagenicity of the emissions. Interestingly, most of this improved consistent reduction in the mutagenicity of the is achieved by just 20% soy biodiesel (B20), which is the primary form of biodiesel available in the U.S. Although soy biodiesel results in less mutagenic emissions compared with petroleum diesel, the mutagenicity of the emissions is still quite high. The data presented in these papers will provide highly relevant information to inform further studies and policy directions of the U.S. EPA for either further promoting or limiting the use of soybeans for the production of soy biodiesel.
Description:
BACKGROUND:Soy biodiesel is the predominant biodiesel used in the U.S., but there is little understanding of the classes of chemicals responsible for the mutagenicity of the emissions.OBJECTIVE: We determined some of the chemical classes responsible for various categories of mutagenicity of the emissions from petroleum diesel (B0) and biodiesel containing increasing concentrations of soy methyl esters (B20, B50, and B100).METHODS: We subjected organic extracts of the emissions from the four fuels to bioassay-directed fractionation by sequential elution on silica gel with solvents of increasing polarity to produce four fractions per fuel. We injected these onto HPLC to produce 62 sub-fractions per fraction based on chemical polarity and evaluated all fractions and sub-fractions for mutagenicity in Salmonella. We correlated the results with the concentrations of 32 polycyclic aromatic hydrocarbons (PAHs) in the fractions.RESULTS: The mutagenicity-emission factors of the fractions generally decreased with increasing concentrations of soy in the fuel. Despite the different chemical compositions of the fuels, the extractable organics of all four emissions shared several similar features: ~60% of the mass was non-polar, non-mutagenic compounds; most of the PAHs were polar; and most of the mutagenicity was due to weakly polar and polar compounds. Some of the mutagenicity of B20 was due to highly polar compounds. CONCLUSIONS: The emissions from soy biodiesel were less mutagenic than those from petroleum diesel, and this was associated with a reduction in the concentrations of various weakly polar, polar, and highly polar mutagens, including PAHs, aromatic amines, nitroarenes, and oxy-PAHs.
