1 Potentiation of ecological factors on the disruption of thyroid hormones by organo-halogenated contaminants in female polar bears (Ursus maritimus) from the Barents Sea Sophie Bourgeon a,b , Astrid Kolind Riemer c , Sabrina Tartu b , Jon Aars b , Anuschka Polder d , Bjørn Munro Jenssen c , and Heli Routti b a The Arctic University of Norway, Department of Arctic and Marine Biology, 9037 Tromsø, Norway (sophie.bourgeon@uit.no) b Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway (sabrina.tartu@npolar.no; jon.aars@npolar.no; heli.routti@npolar.no) c Norwegian University of Science and Technology, Department of Biology, 7491 Trondheim, Norway (bjorn.munro.jenssen@bio.ntnu.no; astridkriemer@gmail.com) d Norwegian University of Life Science, Campus Adamstua, Oslo, Norway (anuschka.polder@nmbu.no) *Corresponding author: Sophie Bourgeon The Arctic University of Norway Department of Arctic and Marine Biology 9037 Tromsø, Norway E-mail : sophie.bourgeon@uit.no Phone : +47-77-64-60-33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59