Rocks outside of Yellowknife, downwind of Giant Mine

Fifty years after the worst of the arsenic emissions from Giant mine, lichen has yet to re-establish itself on the bald granite downwind of the mine. Research is showing that pollution from the mine is far more persistent than anyone suspected. (Richard Gleeson/CBC)

Winter is returning to the subarctic city of Yellowknife, bringing its snow and ice, the only barriers between people and a toxic legacy of the city's gold mining history.

During more than half a century of mining, 19,000 tonnes of arsenic trioxide dust went up the stacks of smelters at the Giant and Con mines and settled on the once-pristine land and lakes in and around Yellowknife.

One teaspoon of that dust is enough to kill an adult.

Though recent scientific research shows that much of the arsenic that went up the stacks is still in the water, sediment and soil, officials and governments have yet to reckon fully with the environmental and human risks.

Due to concerns about arsenic and sewage, since 1968 the city has been drawing its drinking water through an eight-kilometre underwater pipe to the Yellowknife River, upstream of the mines and away from the arsenic fallout.

Now, in a cost-saving measure, the city is considering drawing its drinking water from Yellowknife Bay, near the old Con Mine and a few kilometres from Giant.

At an initial presentation of the idea in June, city council got a taste of the opposition it will face.

"I honestly don't think there's anything more important than putting that [old] pipe back in place," said Georges Erasmus, a member of the local Yellowknives Dene First Nation and former co-chair of the Royal Commission on Aboriginal Peoples.

"Anything else is really reckless."

Erasmus's views reflect a general distrust of official pronouncements that the arsenic contamination poses no immediate health risks.

Map: Leaflet | Tiles © Esri — Esri, DeLorme, NAVTEQ, TomTom, Intermap, iPC, USGS, FAO, NPS, NRCAN, GeoBase, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), and the GIS User Community. Data: NWT Geological Survey, The concentration of arsenic in lake waters of the Yellowknife area (Additional data)

A child poisoned

Much of the contamination in Yellowknife dates back to the dirty beginnings of mining in the city.

Though the federal government knew the mine would be emitting toxic arsenic trioxide dust, it allowed Giant Mine, Con Mine and some smaller gold mines in the Yellowknife area to open in the 1930s and '40s without pollution controls.

The smelter at Giant alone pumped 10,000 kilograms of arsenic trioxide into the air every day for the first three years of operations.

"Over a long, cold Yellowknife winter, it accumulated in the snow," says John Sandlos, a Memorial University assistant professor who has studied the history of Giant Mine.

Sandlos says the Yellowknives Dene First Nation, who have used the Yellowknife area for thousands of years, were particularly vulnerable to the contamination.

"The Dene at that point had no trucked-in or piped-in water and they were using snow for drinking water, and they were drawing water from local lakes and streams, using ice from the bay and so on. As you can imagine, with arsenic accumulating every day — there was 22,000 pounds of it being put out by the mine each day — when you melt water or gather it in the spring, there's a lot of arsenic in there."

NWT Archives/Henry Busse fonds/N-1979-052: 1947

A 1948 postcard shows an aerial view of Giant Mine including tanks, townsite, residences and buildings, only a few of which remain today. In the centre is the plume of pollution from the gold roaster stack. During the early years of the mine, 10,000 kg of highly toxic arsenic trioxide dust blew out of the stack each day. (NWT Archives/Busse/N-1979-052:1234)

In April 1951, people on Latham Island, a part of Yellowknife just a few kilometres across the bay from Giant, got sick. A Dene child died after eating snow laden with arsenic.

The federal government paid the child's parents $750 in compensation and hastily assembled an arsenic committee. It compelled the mine to install an electrostatic precipitator, which cut the arsenic emissions in half.

All the while, the stack continued to belch 10 tonnes of arsenic into the air each day.

"Because of a railroad strike and various other delays, that pollution control did not arrive until October [1951]," says Sandlos.

"So the mine was allowed to operate for a full, additional five or six months without any pollution control equipment whatsoever."

Sandlos says it seemed as if the federal government's first priority was to keep the mines producing.

"It wasn't as if they didn't know they were emitting this stuff. I think what they probably thought, and hoped, was that the smoke stack would disperse it enough and that if it got into local waterways, it would be diluted enough that it wouldn't present a danger."

Giant Mine baghouse

The baghouse at Giant Mine in 1952, with foreman Lloyd Ross. (NWT Mining Heritage Society — George Hunter Collection, #2984)

Workers exposed to arsenic dust

Nowhere were the risks of arsenic minimized more than at the mines themselves.

Norm Plante of Giant Mine

Norm Plante receives a long service award for his work at Giant Mine in 1987. (NWT Mining Heritage Society — Giant Mine Collection)

Norm Plante was probably exposed to more arsenic from the Giant Mine than anyone. For 29 years, starting in the late 1960s, he worked in the mine's baghouse, where arsenic trioxide dust captured by pollution controls was collected.

Every couple of months or so, Plante and others working in the baghouse would have to go inside the hoppers and take the bags off once they were filled with the toxic dust.

"In the late '60s and early '70s, up to '79, all they had on was a rag around their face and no protection," says Plante's widow, Eleanor.

After changing the bags, Norm would have to take three days off because of a rash he developed.

"It would cover most of the areas where he was perspiring, like his face, his neck, his armpits, his knees," says Eleanor.

The only treatment he got was a cream to relieve the itching.

Eleanor says it wasn't until the early 1980s that workers in the baghouse started to get masks and outfits such as rain suits for protection. During the decade before the mine closed in 1999, they were dressed in hazmat outfits that resembled space suits.

Norm Plante died last year, at the age of 69, after being racked by lung, liver and brain cancer. He was not the stereotypical rough-and-tumble miner. He spent his time off gardening, making intricate models out of matchsticks and collecting stamps.

But he was every inch a miner in one important way — he never complained about the dirty and dangerous conditions he worked in. Eleanor says that even on his deathbed last December, Norm never spoke of his suffering.

Partly because of her husband's experience at the mine, Eleanor Plante has lost all confidence in official pronouncements that the arsenic is safe.

"I have no faith in that, no faith at all," she says.

"That mine blew arsenic all over the town, and it's still here."

Eleanore Plante

Eleanor Plante's husband Norm worked in Giant mine's baghouse, where arsenic trioxide dust captured by pollution controls was collected. 'In the late '60s and early '70s, up to '79, all they had on was a rag around their face and no protection.' (Chantal Dubuc/CBC)

A complicated chemical

Arsenic is complicated. This chemical element is often abundant in gold-bearing rock, such as that found around Yellowknife. Locked in the rock, it is released slowly through erosion.

That release becomes almost immediate in the process of separating gold from the rock that holds it, when ore is crushed into fine particles and roasted to separate out the precious metal.

Arsenic does not biodegrade or decompose.

The growing consensus of recent research is that arsenic contamination from the mines is far more persistent than anyone suspected.

In July, the University of Ottawa released a study that focused on a small lake north of Giant Mine. Using core samples taken from the bottom of Pocket Lake, the scientists found that arsenic concentrations in the sediment increased 1,700 per cent as a result of the mine.

Most of that arsenic was deposited during the 1950s and '60s, before pollution controls dramatically decreased the contamination emitted from the roaster stack. It wiped out many species of algae and invertebrates in the lake. Fifty years since the worst of the emissions and 17 years since the roaster was shut down, Pocket Lake has yet to show any signs of recovery.

Pocket Lake outside of Yellowknife

Scientists looking at sediment cores from the bottom of Pocket Lake found arsenic concentrations increased 1,700 per cent in the 1960s. Many species of algae and tiny invertebrates were wiped out. Though arsenic levels have dropped since then, the lake's ecosystem has not recovered. Pocket Lake is just one kilometre from Giant mine. (Richard Gleeson/CBC)

An attractive but dangerous beach

Former Yellowknife MLA Bob Bromley says it's time for a frank public discussion about the contamination.

"I don't feel like we've ever really done that, as governments or as a society, despite the fact that many, many individuals have been extremely concerned about it."

As a teenager growing up in Yellowknife, Bromley and his friends would play on a beach on Great Slave Lake just a few kilometres from where he lived in the city's Old Town.

"I know there were some concerns when we were swimming at the beach," says Bromley.

"Some of the kids would get rashes, and I think there was some discussion… could that be related to some of the pollution coming from the mines."

There was no indication the beach was dangerous, no sign advising people to stay away. But it wasn't really a beach. The sand was actually tailings from Giant Mine — finely crushed rock rich in chemicals and heavy metals, including arsenic.

During the early days of mining, the tailings were simply dumped into the bay.

"There seemed to be very high cancer rates of people either in Yellowknife or who had left Yellowknife who had worked in the mines," says Bromley, himself a cancer survivor.

Bromley likens the issue of arsenic contamination to research on the long-term effects of concussions in sport.

"The doctor that was doing that pioneering work said, 'At least let players be informed, so they can make their own decisions...at least let the players know what the risks are.'"

Arsenic sign at Prospector's Trail

This summer, the N.W.T. government posted signs warning the public of high arsenic concentrations in some small lakes near a popular hiking trail. They're the only signs in the city warning the public of high arsenic concentrations. (Richard Gleeson/CBC)

Arsenic concentrations in lakes near Giant Mine

In April, a year after research came out showing very high concentrations of arsenic in lakes around a new road that passes north of Giant Mine, N.W.T. health officials issued a public advisory, the first they've issued about arsenic in decades.

It warned against swimming regularly in the most contaminated lakes, while downplaying the dangers of wading or fishing in lakes that were less contaminated.  

But the main message was that the high concentrations are nothing to worry about.

Dr. Andre Corriveau, N.W.T.'s chief public health officer, says the Canadian drinking water guideline limit of 10 parts per billion (0.01 ppm) "is very strict."

"It includes a margin of safety. It assumes you're drinking the water daily for 30 years in terms of your risk for cancer," he told media at the time.

"To be slightly above drinking water guidelines for swimming, even for wading and the odd gulp of water, would be entirely safe."

The arsenic concentration in Frame Lake, in the centre of the city, is more than 30 times the guideline limit set for drinking water. The lake is bordered by a popular walking trail, including an active children's playground.

If you search the territorial health department's website, you will find a brochure advising people they should not swim or harvest edible plants around the lake. At the lake itself — which is frequented by tourists as well as locals — there are no signs warning people of the potential danger.

Despite the health department's message that arsenic concentrations in most lakes are nothing to worry about, this summer it posted signs warning the public of high arsenic concentrations in some small lakes near a popular hiking trail that leads out of the busiest park in the territory.

They're the only signs in the city warning the public of high arsenic concentrations.

GIANT-MINE-MEMORIES

Giant Mine in 1992. The head frame, gold roaster stack and many other buildings at the mine have since been torn down as part of a taxpayer-funded clean-up costing more than $1 billion. (The Canadian Press)

Arsenic concentrations in soil

In a presentation Yellowknife city officials give on moving the city's drinking water intake to Yellowknife Bay, the city notes that water in the bay has concentrations below the drinking water limit.

The sediment on the bottom of the bay near the proposed intake has concentrations of 47 to 140 ppm. But the presentation notes that the "average natural background" concentration of arsenic in Yellowknife lake sediment and soil is 150 ppm. That's more than 10 times the Canadian guideline limit set for arsenic in soil.

The "average natural background" number acts as a starting point for the discussion, a way of putting the high numbers into perspective. But research indicates arsenic in and around Yellowknife occurs naturally in much lower concentrations than the city suggests.

As far back as 1978, scientists found that arsenic levels in the Yellowknife region are not abnormally high, ranging from two to 10 ppm, though higher arsenic concentrations do occur.

In a study released in 2000, the Environmental Sciences Group of the Royal Military College stated, "ESG is confident in reporting that the typical background concentration range of arsenic in the Yellowknife area is 3 to 150 ppm."

Somehow, the top of that range became "average natural background."

Research also indicates only a small percentage of the arsenic in Yellowknife is natural. Concentrations in the lakes, sediment and soil increase dramatically every kilometre you move closer to Giant and Con.

Giant Mine town site in 2016

The abandoned Giant mine townsite today. It lies just across Back Bay from Ndilo, where a child died in 1951 after eating snow laden with arsenic. (Chantal Dubuc/CBC)

Arsenic in drinking water causes health crisis in Asia

But where environmental and human health is concerned, it doesn't matter if the arsenic billowed out of the stack of a gold smelter or is just naturally occurring.

"Just because it's natural, doesn't mean it's not dangerous," says Dr. Joanne Santini, a biochemist and instructor at University College in London who has been studying arsenic in the well water of West Bengal, India and Bangladesh.

Naturally occurring arsenic there is responsible for what the World Health Organization describes as "the largest mass poisoning of a population in history."

For decades, tens of millions of people have been drinking well water with arsenic concentrations in the range of 0.05 ppm (five times the Canadian guideline limit).

To complicate matters further, arsenic changes back and forth between more and less dangerous forms depending on its environment.

"There are bacteria that, instead of breathing oxygen, can use arsenic for respiration," Santini says.

"And they can convert that arsenic, which might be inaccessible to humans, into a form that makes it more accessible because it becomes more mobile, more soluble."

In low-oxygen environments, such as lake sediment, arsenic is more likely to change into a form — arsenite — that dissolves more easily in water, allowing it to be transported through the environment and be absorbed by plants, animals and humans.

Santini says lakes with a lot of arsenic in their sediment could very well see increases, rather than decreases, in the arsenic content of the water above over time.

"If I was living in that environment and developed cancer in 20 years, I'd be asking myself, 'Is this because of where I've lived?'" says Santini, referring to Yellowknife.

The crisis in Bangladesh and West Bengal is largely due to the delayed effects of chronic arsenic exposure. No one suspected there was a problem with the water until symptoms started showing up years later.

Giant Mine as seen from Igraham Trail

Giant mine closed in 1999 when owner Royal Oak Mines went bankrupt. The federal government is now responsible for cleaning up the site. (Chantal Dubuc/CBC)

A 'tough job ahead'

Giant Mine is currently undergoing a $1-billion cleanup that will see most of the arsenic dust that was captured by pollution controls stored, indefinitely, in artificially frozen underground chambers. There's been no attempt to address the contamination beyond the borders of the mine sites.

Yellowknife Mayor Mark Heyck says that by next summer, the city hopes to have compiled additional research and sampling to help it decide whether it's safe to start drawing water from the bay instead of replacing the underwater pipe to the river.

"I think council has a tough job ahead of them," he says. "We have to distinguish public concern and public perception from the science that's been done over the last several years."

More and more, the science seems to be validating, rather than refuting, that concern.

Editing: Andre Mayer | Design and Development: Michael Leschart | Photos: Chantal Dubuc, Richard Gleeson