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SOMBA K'E/YELLOWKNIFE - Scientists have discovered bacteria growing underneath Giant Mine that don't mind the cold or the arsenic either.

Researchers from the University College London in Great Britain have identified what they believe is a new strain of bacteria thriving in arsenic-contaminated water seeping through bulkheads and drill holes connected to chambers where 237,000 tonnes of deadly arsenic trioxide is stored.

A member of the Giant Mine technical advisory group examines a colony of arsenic-loving bacteria dripping from a rock face underground. - photo courtesy of Bill Mitchell

The orange-brown blobs of bacteria have been present at the mine for some time but no one knew what they were doing there until recently, according Bill Mitchell, the federally-appointed manager for the cleanup of Giant Mine.

Thomas Osborne and Joanne Santini, two microbiologists with the University College London, found the bacteria are converting the arsenic into a different form more easily extracted from water.

"What they discovered is that the bacteria not only seems to thrive in an arsenic-rich environment but what they appear to be doing is oxidizing Arsenic 3, which is arsenite, to Arsenic 5, which is arsenate," said Mitchell. "If you have a bucket of water that is arsenite and another that is arsenate - they're both probably equally poisonous - but the Arsenic 5 is much more easily removed from the water."

Osborne recently opined to the media that such a discovery could be significant in treating water contaminated with arsenic.

Mayor Gord Van Tighem, who sits on the Giant Mine Advisory Committee, said the researchers' discovery about the bacteria shows that more research needs to be done.

The city forced a environmental review of the Department of Indian and Northern Affairs' clean-up plans for Giant Mine after expressing concerns about the long-term impacts of leaving the arsenic underground. The department plans to freeze the arsenic inside the storage chambers indefinitely.

"The key thing is that (the bacteria) is an indicator that there are things in nature that will deal with a problem," said Van Tighem. "That's why we're looking for some longer-term commitments to fund and study how we'll eventually deal with this."

Mitchell doubts, however, the bacteria at Giant Mine will ever prove useful in removing arsenic there, considering the huge volume of arsenic trioxide stored underground.

"This is not going to solve the problem in any shape or form," said Mitchell.

He said the arsenic is already effectively removed from water seeping through the mine by treating it with hydrogen peroxide.