‘RUSTY’ RIVERS OF THE NORTH
SCIENTIFIC SECRETS HIDDEN AMID UNIQUE YUKON WATERWAYS
Normally, when a river turns pumpkin orange, it’s a clear sign something has gone terribly wrong: a chemical spill, a burst tailings pond or an algae bloom.
But just at the side of the Yukon’s Dempster Highway — a gravel road running from the Klondike to Inuvik — is a remote waterway that has been opaque with pollution since Gwich’in peoples first entered the area.
“It’s rust,” said Matt Herod, a geoscientist who has studied Red Creek, one of two “rusty” waterways along the highway.
Red Creek and nearby Engineer Creek get their colour from iron deposits that have broken to the surface. The water becomes jet black after picking up minerals from an exposed seam of black shale, then turns red as it meanders downstream.
The water can be drunk, but it fails several basic Canadian environmental quality guidelines. Animals avoid it and rocks on the riverbank are dyed a deep reddish hue.
Herod’s analysis found levels of iron, nickel, and zinc at more than 10 times what he considers a “normal” Yukon concentration.
“These numbers are all way out of the ordinary for the rest of the creeks I sampled throughout the Yukon,” he wrote in a post.
Red Creek has presumably been this way since woolly mammoths walked the area. The Yukon was part of Beringia, one of the few areas of North America not to have been carved up by glaciers in the last Ice Age, so it remains a unique time capsule of how the continent looked before human settlement.
While Red Creek’s location along the Dempster makes it one of the most visible “rusty” creeks, it is just one of many hidden in the vast expanses of the Canadian North.
“There are a number of iron formations in the (Northwest Territories), and Nunavut. Where these are at surface they can form large gossans (iron staining) of the rocks and creek beds surrounding them,” said Scott Cairns with the Northwest Territories Geological Survey.
The Mackenzie Mountains, for instance, have several red streams that are visible from space — most notably the Arctic Red. Its Gwich’in name, Tsiigèhnjik, means “river of iron.”
The cause — whether natural or man-made — is the same: water comes into contact with toxic minerals that are normally safely encased below the earth’s surface.
Last week, a Russian river turned blood red after the suspected failure of a filtration dam at a nickel mine. In 2010, 10 people were killed in Devecser, Hungary, after it was deluged by waves of toxic red sludge following a tailings pond collapse at an aluminum works.
Arguably the most famous example is Rio Tinto (Red River), southwestern Spain, that has hosted mining activity for at least 5,000 years. Mining here is so old, the area is considered the birthplace of the Bronze Age.
“No fish or other life existed in this river, neither do people or animals drink it … I took a live frog and threw it in the river and it died without being able to leave the water,” read a 16th-century surveyor’s account of the river.
There have been no biological surveys of the Yukon’s Red Creek. Although it does not appear to support any fish, it could host a unique ecology adapted to extreme situations.
In 2003, NASA scientists collected samples of the bacteria that flourished in the Rio Tinto. The idea was to identify forms of life that might survive in the harsh conditions of subsurface water on Mars.
Around Red Creek, vegetation seems to flourish on the creek’s banks despite the pollution. In a blog post, science writer Victoria Martinez noticed the abundance of wild roses.
“Iron, in gardening circles, is considered a magic elixir for roses. Here, they have it,” she wrote.
The Dempster Highway’s rusty streams have long been a source of fascination for Shawn Ryan, the prospector who discovered the Yukon’s famed White Gold deposit, the largest single gold find since the Klondike Gold Rush.
Had the red creeks been caused by human processes, “it would be North America’s worst mining disaster,” he wrote in an email to the National Post. If the planned billion-dollar cleanup of the Yukon’s Faro mine is any guide, it could cost somewhere in the 12-figures to raise those creeks — and others in the region — to the government standards suitable for aquatic life.
Geological Survey of Canada silt data compiled by Ryan show the Red Creek area includes five streams whose acidity levels rival that of vinegar, all likely the result of surfaced mineral deposits.
What interests him most is the flourishing flora, which he believes show how plant life could rebound in mining-scarred areas.
“My thought has always been that if Mother Nature holds secrets that have allowed vegetation to grow in this acid environment, then we should study her secrets,” he said.
THESE NUMBERS ARE ALL WAY OUT OF THE ORDINARY FOR THE REST OF THE CREEKS I SAMPLED.