title: Combusting vegetable oils in diesel engines: the impact of unsaturated fatty acids on particle emissions and mutagenic effects of the exhaust.
abstract: High particle emissions and strong mutagenic effects were observed after combustion of vegetable oil in diesel engines. This study tested the hypothesis that these results are affected by the amount of unsaturated or polyunsaturated fatty acids of vegetable oils. Four different vegetable oils (coconut oil, CO; linseed oil, LO; palm tree oil, PO; and rapeseed oil, RO) and common diesel fuel (DF) were combusted in a heavy-duty diesel engine. The exhausts were investigated for particle emissions and mutagenic effects in direct comparison with emissions of DF. The engine was operated using the European Stationary Cycle. Particle masses were measured gravimetrically while mutagenicity was determined using the bacterial reverse mutation assay with tester strains TA98 and TA100. Combustion of LO caused the largest amount of total particulate matter (TPM). In comparison with DF, it particularly raised the soluble organic fraction (SOF). RO presented second highest TPM and SOF, followed by CO and PO, which were scarcely above DF. RO revealed the highest number of mutations of the vegetable oils closely followed by LO. PO was less mutagenic, but still induced stronger effects than DF. While TPM and SOF were strongly correlated with the content of polyunsaturated fatty acids in the vegetable oils, mutagenicity had a significant correlation with the amount of total unsaturated fatty acids. This study supports the hypothesis that numbers of double bounds in unsaturated fatty acids of vegetable oils combusted in diesel engines influence the amount of emitted particles and the mutagenicity of the exhaust. Further investigations have to elucidate the causal relationship.
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), University of Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany. buenger@ipa-dguv.de.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bünger
authors.affiliation: Occupational, Social, and Environmental Medicine, Georg-August-University Göttingen, Waldweg 37 B, 37073, Göttingen, Germany.
authors.forename: Jörn F
authors.initials: JF
authors.lastname: Bünger
authors.affiliation: Technology Transfer Center Automotive Coburg (TAC), Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, 96450, Coburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Krahl
authors.affiliation: Thünen Institute of Agricultural Technology, Bundesallee 50, 38116, Brunswick, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Munack
authors.affiliation: Technology Transfer Center Automotive Coburg (TAC), Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, 96450, Coburg, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Schröder
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), University of Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
authors.affiliation: Occupational, Social, and Environmental Medicine, Georg-August-University Göttingen, Waldweg 37 B, 37073, Göttingen, Germany.
authors.forename: Ernst
authors.initials: E
authors.lastname: Hallier
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA), University of Bochum, Bürkle-de-la-Camp-Platz 1, 44789, Bochum, Germany.
authors.forename: Götz A
authors.initials: GA
authors.lastname: Westphal
mesh_terms: D056804:Biofuels / Q000032:analysis*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D005742:Gasoline / Q000032:analysis*; D009152:Mutagenicity Tests; D009153:Mutagens / Q000032:analysis / Q000633:toxicity*; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D010938:Plant Oils / Q000737:chemistry*; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*
chemical_list: D056804:Biofuels; D005231:Fatty Acids, Unsaturated; D005742:Gasoline; D009153:Mutagens; D052638:Particulate Matter; D010938:Plant Oils; D001335:Vehicle Emissions
keywords: Bacterial reverse mutation assay; Biofuel; Diesel engine exhaust; Particle emissions; Unsaturated fatty acids; Vegetable oil