title: Health effects of soy-biodiesel emissions: mutagenicity-emission factors.
abstract: BACKGROUND
  Soy biodiesel is the predominant biodiesel fuel used in the USA, but only a few, frequently conflicting studies have examined the potential health effects of its emissions.
  
  
  OBJECTIVE
  We combusted petroleum diesel (B0) and fuels with increasing percentages of soy methyl esters (B20, B50 and B100) and determined the mutagenicity-emission factors expressed as revertants/megajoule of thermal energy consumed (rev/MJ(th)).
  
  
  METHODS
  We combusted each fuel in replicate in a small (4.3-kW) 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 extracts for mutagenicity in 16 strains/S9 combinations of Salmonella.
  
  
  RESULTS
  Mutagenic potencies of the EOM did not differ significantly between replicate experiments for B0 and B100 but did for B20 and B50. B0 had the highest rev/MJ(th), 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/MJ(th) decreased with increasing biodiesel in the fuel. The emission factor for the 16 EPA Priority PAHs correlated strongly (r(2 )= 0.69) with the mutagenicity-emission factor in strain TA100 + S9, which detects PAHs.
  
  
  CONCLUSIONS
  Under a constant load, soy-biodiesel emissions were 50-85% less mutagenic than those of petroleum diesel. Without additional emission controls, petroleum and biodiesel fuels had mutagenicity-emission factors between those of large utility-scale combustors (e.g. natural gas, coal, or oil) and inefficient open-burning (e.g. residential wood fireplaces).
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: Charly
authors.initials: C
authors.lastname: King
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park , NC , USA .
authors.forename: Leon
authors.initials: L
authors.lastname: Walsh
authors.affiliation: a National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park , NC , USA .
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Kligerman
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 National Risk Management Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park , NC , USA , and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Janek
authors.affiliation: d Department of Applied Environmental Chemistry , TNO , Utrecht , The Netherlands.
authors.forename: Ingeborg M
authors.initials: IM
authors.lastname: Kooter
authors.affiliation: c National Risk Management Research Laboratory, U.S. Environmental Protection Agency , Research Triangle Park , NC , USA , and.
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 Ian
authors.initials: MI
authors.lastname: 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; D000818:Animals; D056804:Biofuels / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D009153:Mutagens / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; 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: Combustion emissions; complex mixtures; mutagenicity