Skip to main content

The Globe and Mail

Independent tests suggest ‘oily sheen’ on Athabasca River may be due to algae

An oily sheen is seen on the Athabasca River near Fort Chipewyan, Alberta., in this July 6, 2013 handout photo.


Independent lab tests suggest a mysterious oily sheen that covered a long stretch of the Athabasca River in northeastern Alberta was most likely due to blue-green algae.

"It is not a petrochemical," said Eriel Deranger, spokeswoman for the Athabasca Chipewyan First Nation, which hired the lab that conducted the tests.

Those scientists say the algae bloom was probably the result of high water from record-breaking rainfall combined with unusually warm temperatures.

Story continues below advertisement

The Athabasca flows through Alberta's oilsands. Energy companies were asked if any of their facilities had released anything, but none had.

An Athabasca Chipewyan band member first noticed the sheen the night of July 5 while boating between Fort McMurray and Fort Chipewyan.

The town's water intake was closed on Saturday. By Monday, the sheen had been spotted at Fort Chipewyan and the slick was present over more than 100 kilometres of river.

Residents began to spot dead fish floating in the river and on Lake Athabasca.

Samples taken by band members and analyzed in the lab suggest the fish probably suffocated as the out-of-control algae growth used up all the available oxygen.

Deranger said the sheen is still visible in some stretches of the river, but plans were to reopen Fort Chipewyan's water intake Thursday.

Algae blooms occur periodically on the Athabasca — but not like this, Deranger said.

Story continues below advertisement

"We definitely have problems with algae blooms, but not this expansive."

Report an error
As of December 20, 2017, we have temporarily removed commenting from our articles. We hope to have this resolved by the end of January 2018. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to If you want to write a letter to the editor, please forward to