What’s that orange hue in Mackenzie Delta waterways?

Have you noticed an orange hue in the Peel or Mackenzie rivers?

You’re not alone. 

“Most of the questions have been: ‘What is it?'” laughs Gila Somers, a watershed management advisor with the Department of Environment and Natural Resources.

Somers says the department has been working with residents since 2016 to help answer that question. She says investigating the “orange dusting” — usually seen along the shore or in the very centre of the water — is part of a community-based water quality monitoring program.

“There’s multiple [phenomena] that could be happening at the same time and we are trying to identify and really conclude what those are.”

3 theories so far

She says samples of the dusting have confirmed an iron bacteria, “which is naturally forming between heavy sediments in the water.”

Somers says the iron bacteria is 100 per cent safe for the aquatic environment and for people to drink. 

“The fish are healthy and adapted to this phenomenon,” she said. 

But the dusting is likely more than iron bacteria, she says. 

“Because there is a short timeline of when these observations [of the orange dusting] happen … it happens typically between mid-late July and the beginning of August and has a short appearance … we could be looking at multiple things.”

Officials with ENR say the ‘orange dusting,’ shown here in a small stream, could be iron bacteria, spruce rust or possibly algae. (N.W.T. Department of Environment and Natural Resources)

She says the dusting could be spruce rust, a fungus that attaches to spruce trees and turns the needles red. The theory is that those red particles die off “and then disperse … through the air onto water.”

Somers says spruce rust doesn’t occur yearly, but officials confirmed that Alaska had a spruce rust cycle a couple of years ago, which coincides with what happened in the Mackenzie Delta region in 2017.

Somers says the dusting could also be algae, which they’d have to further investigate to make sure it’s safe to be in the waterways. She says they haven’t confirmed any cases of that so far.

Gila Somers is a watershed management advisor with the Department of Environment and Natural Resources. (Gila Somers)

Somers says they hired a non-profit called C-CORE. It did a remote sensing analysis on historical events to find out when and where the orange hue has been found over the last 10 years.

“It was quite successful in terms of being able to identify that these [phenomena] are ongoing and aren’t new. That we have observed this in the past.”

Somers says people can get sampling kits in their communities to collect any of the orange dusting they may see. They can bring the samples to their local ENR office. 

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