title: Health effects of soy-biodiesel emissions: bioassay-directed fractionation for mutagenicity.
abstract: BACKGROUND
  Soy biodiesel is the predominant biodiesel in the USA, but there is little understanding of the classes of chemicals responsible for the mutagenicity of its emissions.
  
  
  OBJECTIVE
  We determined some of the chemical classes responsible for the mutagenicity of the particulate matter (PM) 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 PM 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 high performance liquid chromatography 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 had similar features: ∼60% of the mass was nonpolar, 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 PM from soy biodiesel emissions was less mutagenic than that from petroleum diesel, and this reduction was associated with reduced concentrations of various weakly polar, polar, and highly polar mutagens, including PAHs, aromatic amines, nitroarenes, and oxy-PAHs.
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .|b Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina , Chapel Hill , NC , USA .
authors.forename: Esra
authors.initials: E
authors.lastname: Mutlu
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .
authors.forename: Sarah H
authors.initials: SH
authors.lastname: Warren
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .
authors.forename: Peggy P
authors.initials: PP
authors.lastname: Matthews
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .
authors.forename: Judith E
authors.initials: JE
authors.lastname: Schmid
authors.affiliation: c Department of Applied Environmental Chemistry , TNO , Utrecht , The Netherlands , and.
authors.forename: Ingeborg M
authors.initials: IM
authors.lastname: Kooter
authors.affiliation: d National Risk Management Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Linak
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .
authors.forename: M
authors.initials: M
authors.lastname: Ian Gilmour
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park , NC , USA .
authors.forename: David M
authors.initials: DM
authors.lastname: DeMarini
mesh_terms: D000393:Air Pollutants / Q000633:toxicity; D056804:Biofuels / Q000633:toxicity*; D001681:Biological Assay / Q000379:methods; D009153:Mutagens / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity; D012475:Salmonella / Q000187:drug effects* / Q000378:metabolism; D013025:Glycine max / Q000633:toxicity*; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D056804:Biofuels; D009153:Mutagens; D052638:Particulate Matter; D001335:Vehicle Emissions
keywords: Complex mixtures; PAHs; diesel exhaust; mutagenesis