New Method Uses Waste to Clean Arsenic From Lake Contaminated by Gold Mine


Levels of arsenic in Northern Ontario’s Long Lake are so high that some local residents can no longer drink the water.

Arsenic has been leaching into the lake from tailings at the abandoned Long Lake Gold Mine, which operated intermittently until 1937 and produced approximately 200,000 tonnes of tailings, discharged directly to the environment without containment.

Now a team of researchers from the University of Waterloo has shown that a passive form of remediation that uses common waste materials can remove virtually all of the arsenic from samples of the lake water. Their results are published in the Journal of Hazardous Materials.

The scientists found that mixing wood chips, leaf mulch, and iron filings (left over from manufacturing car engines) with limestone creates conditions that encourage bacteria to grow. The bacteria pull the arsenic from the water by converting it to a solid form that is essentially trapped within the waste material filter.

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