title: Risk evaluation of the Arctic environmental POP exposure based on critical body residue and critical daily dose using captive Greenland sledge dogs (Canis familiaris) as surrogate species.
abstract: The risk from POP (persistent organic pollutant) exposure and subsequent reproductive, immunotoxic and liver histopathological effects was evaluated in a classical parallel trial on Greenland sledge dogs (Canis familiaris) fed contaminated minke whale (Balaenoptera acutorostrata) blubber. First the critical body residues (CBRs) were estimated using the physiologically-based pharmacokinetic (PBPK) model for seven POP compounds based on rat critical daily doses (CDDs). These were then compared with the actual daily oral POP doses (DD) and body residues (BR) in the sledge dogs by calculating risk quotients (RQDD: DD/CDD; RQBR: BR/CBR; ≥1 indicates risk). The results showed that risk quotients for reproductive, immunotoxic and liver histopathological effects were significantly lowest in the control group (p<0.01) while risk quotients based on daily doses (RQDD) were significantly lower than RQs based on body residues (RQBR) (all p<0.01). RQBR in the exposed group ranged from 1.0-12 for reproductive and immunotoxic effects while those for liver histopathological effects ranged from 0.7-3.0. PCBs (polychlorinated biphenyls) and chlordanes were the dominant driver behind high immune and reproductive RQs while dieldrin was the most important factor behind RQs for liver histopathology. Principal component analyses and Spearman rank correlation analyses showed that complement and cellular immune parameters were significantly negative correlated with RQBR (all p<0.05) while logistic regression showed that RQDD had a significant effect on the number of born cups (p=0.03). No significantly relations were found between RQs and hormone concentrations, number of gestations, antibody titres or liver histopathology. These results confirm previous studies showing that POP exposure negatively impacts steroid hormones, various immune parameters, as well as liver histopathology in sledge dogs. It is also clear that RQBR is the best reflector of health effects from POP exposure and that it is especially accurate in predicting immune and reproductive effects. We recommend that PBPK modelled (CBR) and RQBR should be used in the assessment of POP exposure and health effects in Arctic top predators.
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark. Electronic address: cs@bios.au.dk.
authors.forename: Christian
authors.initials: C
authors.lastname: Sonne
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Gustavson
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Igor
authors.initials: I
authors.lastname: Eulaers
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Desforges
authors.affiliation: Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Letcher
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Frank F
authors.initials: FF
authors.lastname: Rigét
authors.affiliation: Toxicology Laboratory, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100, Denmark.
authors.forename: Bjarne
authors.initials: B
authors.lastname: Styrishave
authors.affiliation: Faculty of Science and Technology, Department of Bioscience, Arctic Research Centre, Aarhus University, P.O. Box 358, DK-4000 Roskilde, Denmark.
authors.forename: Rune
authors.initials: R
authors.lastname: Dietz
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000818:Animals; D001110:Arctic Regions; D004285:Dogs / Q000378:metabolism*; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006116:Greenland; D008099:Liver / Q000187:drug effects; D050636:Minke Whale; D009930:Organic Chemicals / Q000633:toxicity*; D011897:Random Allocation; D012098:Reproduction / Q000187:drug effects; D018570:Risk Assessment
chemical_list: D004785:Environmental Pollutants; D009930:Organic Chemicals
keywords: Critical body residue; Critical daily dose; Polychlorinated biphenyls; RQs; Risk quotients