Due to their filter feeding habits and poor capacity to biotransform xenobiotics, blue and fin whales (Balaenoptera musculus and B. physalus) are likely exposed to a wide range of environmental chemicals, which may negatively affect their health. This research project will quantify a wide range of emerging and legacy toxic compounds in the blubber of blue and fin whales sampled from Svalbard. Cause-effect relationships between chemical exposure and effects will be established by testing activation of blue and fin whale nuclear receptors and the aryl hydrocarbon receptor (AhR) by relevant environmental chemicals and mixtures of compounds. We will also investigate transcriptional and metabolome responses in whale blubber tissue explants and/or cell cultures exposed to pollutants in vitro. Furthermore, we will develop methods to analyse hormones in whale blubber tissue for future correlative studies. Finally, we will compare chemical exposure in blue and fin whales to other whale species feeding in Arctic/sub-Arctic waters in the North Atlantic in relation to their feeding habits. The project will lead to several high quality peer-reviewed publications. In addition, we will communicate this highly relevant research to environmental management agencies as well as to media.