Polycyclic aromatic compounds in Canadian Arctic seabirds: Spatial and temporal trends

The Canadian Arctic is undergoing significant environmental changes. As climate change continues to drive the reduction in the extent and thickness of sea ice, this region is experiencing an increase in shipping and other industrial activity, notably mining. In addition to existing natural oil and gas seeps, greater industry has led to growing concerns about the release of oil and gas contamination into vulnerable Arctic ecosystems. Polycyclic aromatic compounds (PACs) are a broad class of organic contaminants that are associated with oil and gas, many of which are persistent, bioaccumulative and toxic. This study examines spatial and temporal PAC trends in thick-billed murre (Uria lomvia) eggs between 1993 and 2024 from Prince Leopold Island, Nunavut (high Arctic; 74°02'N, 90°00'W) and Appatuurjuaq (Coats Island), Nunavut (low Arctic; 62°51'N, 82°29'W). Forty-eight polycyclic aromatic hydrocarbons (PAHs) and alkylated polycyclic aromatic hydrocarbons (APAHs) were quantitated using gas chromatography-tandem mass spectrometry. Overall, concentrations of total PACs, alkylated high molecular weight (AHMW) PACs and high molecular weight (HMW) PACs were greater in eggs from birds breeding in the high versus low Arctic, suggesting potential spatial differences in PAC exposure. While concentrations of PACs did not change dramatically from 1993 to 2024 at either location, considerable variation among individual years was observed. As interest in Canada's northern shipping routes continues to grow, monitoring of PACs in seabird eggs will survey as a practical sentinel system to assess potential changes in contamination that may pose risks to Arctic wildlife and their environments.