Yukon biologist warns impacts to creek near Eagle mine contained, but could reach tipping point
Mark O’Donoghue told the Yukon River panel last week unknowns remain
While impacts to Haggart Creek because of the Eagle Gold mine failure are localized right now, risks of further contamination remain so great that may not hold, according to a seasoned fisheries biologist who works with the First Nation of Na-Cho Nyäk Dun.
The creek has been heavily monitored since part of the mine — where cyanide was used to process ore — failed in June with an enormous rockslide. Since then, contaminated water has been seeping into the environment. The latest publicly available government data shows cyanide in the creek continues to spike to levels so high fish could be killed.
Last week, Mark O'Donoghue told the Yukon River Panel that impacts are limited to the upper eight-kilometre reaches of the creek, which are salmon-bearing and full of grayling.
Presenting to panel members in Anchorage, Alaska, O'Donoghue said a plume of contaminated groundwater, which continues to seep into the creek, is of chief concern — a problem compounded by spring melt.
"The direction it's headed right now is not good," he said. "There are a lot of uncertainties and risks here still. There's a lot of questions about how the groundwater is migrating through the soils, where it's gonna come up, what rates it's gonna come up, and also how effective can we be intercepting this, using wells and sumps.
"This event has really led to some deep personal hurts and lots of anger and frustration and sadness," he added. "It's exacerbated by the fact that salmon fishing is no longer something people can do right now, either."
Na-Cho Nyäk Dun has expanded its monitoring efforts, O'Donoghue said. Not only is the First Nation looking at water quality and fish, it is also taking samples of insects that live at the bottom of the creek, sediments and aquatic fur-bearing animals like muskrats.
"It's a big concern of hunters in the area that, you know, some of the toxins from the creek are going to get into the population there, so we're gathering this to make sure everything's safe and also to give us a baseline for future monitoring," O'Donoghue said.
"We've been meeting with [the Department of Fisheries and Oceans] to talk about options for what happens in the spring, when the grayling wanna start coming up this creek, if it's toxic, and what we can do about that."
The storage and treatment of contaminated water has been a serious issue since the mine failure happened, with hundreds of millions of litres of cyanide-contaminated water now being held in storage ponds at the site. That volume of stored water continues to grow. One storage pond recently sprung a leak.
O'Donoghue said on-site storage continues to worry people.
"There are questions as to whether it will be enough storage to handle the amounts that we get from freshet," he said. "There's a lot of uncertainty right now as to how effective we can actually be with intercepting that groundwater, so we can keep the negative effects local."
Erin Dowd, who works for the Department of Mines, said during the panel meeting that receiver PricewaterhouseCoopers has, to date, installed 28 monitoring wells at the mine site and 11 that are capable of capturing contaminated groundwater. Dowd also said there's 309,000 cubic metres of storage across five ponds.
Tr'ondëk Hwëch'in also took water samples
Downriver is Tr'ondëk Hwëch'in, which, also concerned about environmental impacts, has been monitoring water quality in the McQuesten, Stewart and Yukon Rivers.
Karlie Knight, the fish and wildlife manager at the First Nation, said crews didn't detect cyanide, ammonia and mercury, at least up until mid-November. Knight said there was one reading of chromium that was above water quality guidelines.
"We're ready to go take more samples, if need be," she said. "We'd also like to include methylmercury parameters in any future water quality testing."
Methylmercury, a compound of mercury, forms when it settles in, say, an eddy and begins to interact with bacteria in the water. It's a highly poisonous neurotoxin that can biomagnify.
"There's a lot of questions going around," Knight said. "Is the water safe to drink? Is it safe to eat the animals harvested in the area? There's still a lot of questions and not a lot of answers at this point."
The territory has urged people to avoid drinking water and eating fish harvested in the immediate vicinity of the mine. It's also said that harvesting wildlife or gathering plants "is not considered a health risk at this time."