Yellowknife residents are being warned to stay out of the water at the mouth of Baker Creek and north of the public boat launch between 6 a.m. and 8 a.m. until Saturday.
The Giant Mine remediation team will be using low-voltage electricity to catch fish for testing. Anyone in the water who is not wearing protective gear is at risk.
Adrian Paradis, the acting manager for the Giant Mine remediation project, said the federal government requires the testing.
"We do this in both Baker Creek and what's called a reference area. And so we do that in another section of the Yellowknife River and we're looking to see if there's any impacts or differences between the fish that are caught in our exposure area to the reference area," said Paradis.
This testing has been ongoing since 2004.
Paradis said the testing has shown that there are differences between fish caught near Giant Mine and those caught in the Yellowknife River. However, he said it's too soon to tell what is causing those differences.
In 2015, when the next phase of testing will happen, they’ll be able to determine the cause.
Baker Creek runs through Giant mine, which has been called the most contaminated mine site in Canada. There are thousands of tonnes of arsenic trioxide under the ground at the site. The remediation team is currently freezing the toxic dust into place as removing it all from the sitehttp://www.cbc.ca/news/canada/north/story/2011/04/27/giant-mine-arsenic-test.html is next to impossible.