Environmental Research 106 (2008) 72–80 Greenland sledge dogs (Canis familiaris) develop liver lesions when exposed to a chronic and dietary low dose of an environmental organohalogen cocktail Christian Sonne a,Ã , Pall S. Leifsson b , Rune Dietz a , Maja Kirkegaard a , Asger L. Jensen c , Soheila Shahmiri d , Robert J. Letcher d a Section for Contaminants, Effects and Marine Mammals, Department of Arctic Environment, National Environmental Research Institute, University of Aarhus, Frederiksborgvej 399, P.O. Box 358, DK-4000 Roskilde, Denmark b Department of Veterinary Pathobiology, Faculty of Life Sciences, University of Copenhagen, Bu ¨ lowsvej 17, DK-1870 Frederiksberg, Denmark c Department of Small Animal Clinical Sciences, Faculty of Life Sciences, University of Copenhagen, Bu ¨ lowsvej 17, DK-1870 Frederiksberg, Denmark d National Wildlife Research Centre, Science and Technology Branch, Environment Canada, Carleton University (Raven Road), Ottawa, Ont., Canada K1A 0H3 Received 12 March 2007; received in revised form 22 May 2007; accepted 3 August 2007 Available online 29 September 2007 Abstract We assessed the relationship between exposure to organohalogen polluted minke whale (Balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 Greenland sledge dogs (Canis familiaris). The prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all Chi-square: po0.05). In case of granulomas, the frequency was significantly highest in the bitches (P generation) while the prevalence of portal fibrosis was highest in the F generation (pups) (both Chi-square: po0.05). No significant difference between exposed and controls was found for bile acid, ALAT, and ALKP, while ASAT and LDH were significantly highest in the control group (both ANOVA: po0.05). We therefore suggest that a daily intake of 50–200 g environmentally organohalogen polluted minke whale blubber can cause liver lesions in Greenland sledge dogs. It is reasonable to infer that other apex predators such as polar bears (Ursus maritimus) and humans may suffer from similar impacts. r 2007 Elsevier Inc. All rights reserved. Keywords: Alanine aminotransferase (ALAT); Alkaline phosphatase (ALKP); Aspartate aminotransferase (ASAT); Balaenoptera acutorostrata; Bile acid; Blubber; Canis familiaris; Chlordanes; Dichlorodiphenyltrichloroethane (DDT); Dieldrin; HCB; Hexacyclohexanes (HCHs); Histopathology; Liver; Lactate dehydrogenase; LHD; Mercury (Hg); Minke whale; Organohalogen contaminants; Polar bear; Polybrominated diphenyl ethers (PBDEs); Polychlorinated biphenyls (PCBs); Sledge dogs; Ursus maritimus; West Greenland 1. Introduction As other mammalian top predators in the Arctic such as Arctic foxes (Alopex lagopus) and polar bears (Ursus maritimus), Greenland sledge dogs (Canis familiaris) rely on marine mammals as a food source (Born, 1983; Sonne et al., 2006a). Marine mammals in East Greenland, Svalbard and the Kara Sea carry the highest concentrations of long-range transported anthropogenic toxic and xe- noendocrine disrupting organohalogen compounds (OHCs) such as polychlorinated biphenyls (PCBs), di- chlorodiphenyltrichloroethane (DDT), and polybromi- nated diphenylethers (PBDEs) (AMAP, 2004). OHCs are suspected to have various impacts on endocrine (Braathen et al., 2004; Haave et al., 2003; Oskam et al., 2003, 2004; Skaare et al., 2001), immunological (Bernhoft et al., 2000; Lie et al., 2004, 2005), reproductive (Wiig et al., 1998; Sonne et al., 2006b), bone (Sonne et al., 2004), and internal organ morphology (Sonne et al., 2005, 2006c) markers in ARTICLE IN PRESS www.elsevier.com/locate/envres 0013-9351/$ - see front matter r 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.envres.2007.08.010 Ã Corresponding author. Fax: +45 46 30 19 14. E-mail address: csh@dmu.dk (C. Sonne).