SHORT RESEARCH AND DISCUSSION ARTICLE Polycyclic aromatic hydrocarbons (PAHs) reduce hepatic β-oxidation of fatty acids in chick embryos Ola Westman & Marcus Nordén & Maria Larsson & Jessica Johansson & Nikolaos Venizelos & Henner Hollert & Magnus Engwall Received: 13 July 2012 / Accepted: 10 December 2012 # Springer-Verlag Berlin Heidelberg 2012 Abstract Polycyclic aromatic hydrocarbons (PAHs) are widespread fused-ring contaminants formed during incomplete combustion of almost all kind of organic materials from both natural and anthropogenic sources. Some PAHs have been shown to be carcinogenic to humans, and a wide range of PAHs are found in wildlife all around the globe including avian species. The purpose of this project was to assess the effects of a standard mixture of 16 PAHs (United States Environmental Protection Agency) on the hepatic fatty acid β-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The hepatic β-oxidation was measured using a tritium release assay with [9,10- 3 H]-palmitic acid (16:0) as substrate. Treated groups were divided into groups of 0.05, 0.1, 0.3, 0.5, and 0.8 mg PAHs/kg egg weight. The hepatic β-oxidation was reduced after exposure in ovo to the 16 PAHs mixture com- pared to control. The mechanisms causing reduced fatty acid oxidation in the present study are unclear, however may be due to deficient membrane structure, the functionality of enzymes controlling the rate of fatty acid entering into the mitochondria, or complex pathways connected to endocrine disruption. To the best of our knowledge, this is the first time a PAH-caused reduction of hepatic β-oxidation of fatty acids in avian embryos has been observed. The implication of this finding on risk assessment of PAH exposure in avian wildlife remains to be determined. Keywords Polycyclic aromatic hydrocarbons . PAHs . Avian . Embryo . Hepatic . β-Oxidation . Palmitic acid Background, aim, and scope The major emission of polycyclic aromatic hydrocarbons (PAHs) into the atmospheric, aquatic, and terrestrial system originates from anthropogenic activity such as petroleum re- fining and other industrial processes (Shen et al. 2011). PAHs are also found in cigarette smoke, heating fumes, and grilled food products (Ohura et al. 2003; Sinha et al. 2005). The global emission of the 16 PAHs listed by the United States Environmental Protection Agency (US EPA) as priority pol- lutants was approximately 520,000 tons in 2004 (Zhang and Tao 2009). PAHs are included in the Convention on Long- Range Transboundary Air Pollution Protocol on Persistent Organic Pollutants (United Nations Economic Commission) and some PAHs are well known to be potentially carcinogenic to humans according to the International Agency for Research on Cancer (1987). Toxicological effects of PAHs exposure have been examined in a diverse suite of studies, including microorganisms, invertebrates, fish, reptiles, and mammals with documented effects on toxicity and tumor formation, etc. (Andersson et al. 2009; Bonnet et al. 2005; Chen and Chen 2011; Kammann 2007; Kannan and Perrotta 2008; Lehr and Jerina 1977; Moldoveanu 2010; Perera and Edwards Responsible editor: Philippe Garrigues O. Westman (*) : M. Nordén : M. Larsson : M. Engwall Man-Technology-Environment Research Center, School of Science and Technology, Örebro University, 70182 Örebro, Sweden e-mail: ola.westman@oru.se J. Johansson : N. Venizelos Department of Clinical Medicine, School of Health and Medical Science, Örebro University, 70182 Örebro, Sweden H. Hollert Inst. For Environmental Research, Department of Ecosystem Analysis, RWTH Aachen University, 52074 Aachen, Germany Environ Sci Pollut Res DOI 10.1007/s11356-012-1418-7