New research debunks a lingering belief that "natural arsenic" significantly contributes to high levels of the toxic substance around Yellowknife, according to CBC Canada. For many years, elevated levels have been attributed to natural bedrock geology, but geology experts from Queen's University say it's not so.
"The high values are due to pollution from human impact … Most of the emissions are from the roasters at Giant and Con [mines]," said Dr. Heather Jamieson, a professor and geology expert from Queen's.
During more than half a century of mining, 19,000 tonnes of toxic arsenic trioxide dust went up the stacks of smelters at the Giant and Con gold mines and settled on the once-pristine land and lakes in and around Yellowknife.
The new study establishes a much lower figure for naturally occurring arsenic — five times less than previous estimates for the Yellowknife region.