Invasive clover in Yukon may help clean mine water: researcher

But researchers have stalled in their efforts to test what they found in a real-world setting.

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Research suggests a pesky invasive plant found in many areas of the Yukon could be used to clean contaminated mine water.

But the closure of the Minto mine, 150 miles north of Whitehorse, last summer means researchers have stalled in their efforts to test what they found in a real-world setting.

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Master’s student Taylor Belansky said a Sea-Can full of lab equipment for his pilot project remains at the site after the copper and gold mine was abandoned in May.

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Belansky’s work at Yukon University focused on bacteria that can remove nitrates from mine water by converting the contaminant into gas. But doing so more effectively depended on finding the right source of nutrients for the bacteria.

He said he tried food sources ranging from wood chips to waste from the local brewery, but found that the invasive white sweet clover helped remove 99 percent of the nitrates from the water.

In practice, the contaminated water would be pumped through long plexiglass tubes containing both the bacteria and the clover. The water would flow at a rate that would allow the bacteria enough time to consume the nitrates.

Belansky discovered that this passive method of cleaning water, using bacteria instead of filters or other forms of human management, could work in the cold temperatures of the north in a similar way to what is already used in some projects in the south.

“What we really needed to do was make sure we could use it and adapt the system to work in cold climates,” he said.

“So, we did it by changing the amount of food we gave (the bacteria) and also changing… how long it took for the water to go through the system so that the bacteria could be in contact with the contaminated water and have time to remediate it.” ”.

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“Those are the two factors that we found we could manipulate to make sure this treatment system worked in the cold.”

Nitrates and nitrogen exist naturally in the environment, but activities such as mine explosions can release more into the environment and upset the balance of an ecosystem.

Belansky said too many nitrates can cause algae blooms, affecting oxygen levels in the water and suffocating fish, as well as potentially affecting drinking water.

He said Minto workers would have no problem finding white sweet clover, which grows in much of the territory, including near the mine.

The Yukon Invasive Species Council warns that the plant “readily invades open areas and forest clearings, as well as riverbanks,” driving out other species and degrading natural grasslands.

“In reality, the mines are mandated to manage their invasive species on site. So we would never want to intentionally plant it, we wouldn’t want to propagate it in a way that would allow it to continue its invasion of the natural ecosystem,” Belansky said.

“It’s more like harvesting it, getting it out of the places where it’s a problem and containing it in our treatment system.”

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Belansky said the pilot project would examine how bacteria respond to fluctuating temperatures in nature, how often clover should be added to soil and whether it performs better after being composted.

“The rest of the research team hopes to be able to access the Minto site in the coming years, hopefully next year, to establish that pilot project and test the system under those conditions,” he said.

The Yukon government, which controls entry to the site along with the Selkirk First Nation, did not immediately respond to questions about whether the project would be allowed to go ahead.

For now, Belansky said he is working to finish his master’s thesis and waiting to receive DNA tests that will reveal exactly what type of bacteria is in Minto’s soil. He then hopes to publish his findings.

The mine was put up for sale by a court-appointed receiver in August.

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