GLYCEROL DIALKYL GLYCEROL TETRAETHERS (GDGTs) AS PROXIES TO TRACK URANIUM MILL RELATED ACID ROCK DRAINAGE IN WHISKEY LAKE, ON

As the threat of climate change continues to grow, nuclear energy has risen to prominence as an alternative to fossil fuels; in Canada, it is expected to play a key role in achieving net-zero emissions by 2050. As a result, a more comprehensive understanding of the environmental consequences of uranium mining and milling is essential, particularly as the industry plans to expand into traditional Indigenous lands. Here, we investigate the impacts of uranium mining and milling in sediment cores taken from Whiskey Lake, which was exposed to two episodes of acidic loading from the uranium mines and mills operating in Elliot Lake for approximately 40 years (~1955-1996). We focus on glycerol dialkyl glycerol tetraethers (GDGTs), membrane lipids synthesized by archaea and bacteria, as a novel tool to track acid mine drainage resulting from uranium mining and milling. These lipid structures are sensitive to changes in environmental conditions, and while GDGT-temperature relationships have been widely used for paleoclimatic reconstruction, the GDGT-pH relationship – where increasing cyclization corresponds generally to increasing pH – is relatively less explored. We predicted increased GDGT cyclization in sediments deposited during the release of acid rock drainage associated with intensified mining and milling activity. Results show the utility of GDGTs in tracking periods of acid rock drainage in lake sediments.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Kayla Lerette, University of Ottawa (klere057@uottawa.ca)

Authors:

Kayla Lerette, Department of Earth and Environmental Science, University of Ottawa  (klere057@uottawa.ca)

Bowen Xiao, Department of Biology, University of Ottawa  (bxiao049@uottawa.ca)

Dënë Cheecham-Uhrich, Clearwater River Dënë Nation  (dcheecham-uhrich@iegconsulting.com)

Linda Kimpe, Department of Biology, University of Ottawa  (linda.kimpe@uottawa.ca)

David Eickmeyer, Department of Biology, University of Ottawa  (deickmey@uottawa.ca)

Richard Goulet, Applied Geochemistry and Impact Assessment Group, Environmental Sciences Division, CanmetMINING, Natural Resources Canada  (richard.goulet@NRCan-RNCan.gc.ca)

Sean Langley, Applied Geochemistry and Impact Assessment Group, Environmental Sciences Division, CanmetMINING, Natural Resources Canada  (sean.langley@NRCan-RNCan.gc.ca)

Jules Blais, Department of Biology, University of Ottawa  (jules.blais@uottawa.ca)