Presentation NL Polar Day 2026: Hydrological Contaminant Mobilisation from Thawing Permafrost in Alaska

Title: Hydro-thermal contaminant mobilization from thawing permafrost in Alaska    

Thawing of permafrost in Alaska increases the risk of contaminant mobilisation into sensitive ecosystems and communities. Analysis of a contaminant site database reveals over 1,200 active contaminated sites on permafrost in Alaska—30% of which are military installations, containing up to 39 different pollutants. The Aquatic Hazard potential (Ω) is derived from site-specific characteristics, including contaminant toxicity, solubility, and distance to the nearest waterbody. Although many contaminants exhibit low solubility, 40% of sites are located within 1 km of rivers or lakes, and over 70% within 1 km of the ocean, placing aquatic and coastal systems at risk. Using the hydro-thermal model CryoGridLite, we simulate future lateral hydrothermal mobilisation potential (Φ) under the SSP1-2.6 and SSP5-8.5 climate scenarios. Results indicate increasing mobilisation risk for contaminated sites located in the Alaska Tundra and Alaska Boreal Interior ecoregions under both emission scenarios. While southern Alaska exhibits the highest absolute hydrothermal mobilisation potential due to deeper thaw, northern coastal regions show the largest relative increases in mobilisation risk driven by substantial increases in active layer thickness. This study provides novel insights into thaw-induced contaminant release under climate change. Communities—particularly Indigenous populations in coastal regions who rely on local water and food resources—may face increasing exposure risks.