Mount Allison University professor Joshua Kurek takes a core sample at Dartmouth as part of research into contaminants from gold mines.
Mine tailings pollutant is a sand-like substance that remains after rock containing arsenic and gold has been crushed and spread on liquid mercury to bring out the gold. The residue from the process is therefore very toxic.
As expected, the concentration of toxins has decreased since mining stopped in most cases. But there were two exceptions.
The sediments of Gegogan Lake, downstream of Goldenville, contain mercury concentrations as high as during the peak period of #x27;mining. Researchers believe that tailings released into the lake still contain high levels of this chemical.
The situation is worse in Lake Charles. Now located in an urban area, the lake received tailings from the gold mining of the Montague mine in Dartmouth.
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This site where the Montague Gold Mines gold mine was located was still scheduled to be decontaminated in 2022.
Arsenic levels in Lake Charles have in fact has increased since 2010.
Branaavan Sivarajah says low oxygen levels caused by global warming likely triggered a chemical reaction that breaks down arsenic binding compounds.
Algae and other matter sink to the bottom and decompose, reducing oxygen levels.
We are seeing a transition from lake sediments, which act as sinks of contaminants due to the various environmental changes currently occurring, he notes.
In the case of Lake Charles, we find that recovery may also be influenced by contemporary environmental changes linked to urbanization and climate change.
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The traces left by gold extraction at Montague Gold Mines are clearly visible in this satellite image.
Mercury in Lake Gegogan and arsenic in Lake Charles exceed guidelines set by the Canadian Council of Ministers of the Environment , a federal benchmark for environmental contamination.
In Montague and Goldenville, tailings fields are also used by all-terrain vehicles, which that has accelerated the erosion of tailings that are moved to downstream aquatic ecosystems, the study says.
The report calls for more monitoring to track the movement of mine tailings.