'Off site' arsenic contamination a growing public concern in Yellowknife

The main worry about Giant Mine for people living in the Yellowknife area is no longer the 237,000 tonnes of highly toxic arsenic stored underground at the mine — it’s the arsenic in their children’s playgrounds and city lakes.

Federal, N.W.T. govt's still undecided about which is responsible for contamination outside Giant mine site

A view of Ndilo with Yellowknife in the background from a rocky hill in the community. Residents are concerned that the community's school is near an arsenic 'hot spot'. (Walter Strong/CBC)

The main worry about Giant Mine for people living in the Yellowknife area is no longer the 237-thousand tonnes of highly toxic arsenic stored underground at the mine — it's the arsenic in their children's playgrounds and city lakes.

"It's a really hard thing to live with, that our kids are contaminated, day in and day out," said Margaret Erasmus, a Yellowknives Dene member and one of the founders of Kalemi Dene School in Ndilo.

Speaking Tuesday night at the first public meeting of the Giant Mine Oversight Board, a watchdog board established to monitor the cleanup of Giant Mine, Erasmus was referring to one of the so-called arsenic "hot spots" near the only school in the community.

The Giant Mine Oversight Board held its first public meeting yesterday evening where citizens expressed concerns about so-called 'off-site' contamination. (Richard Gleeson/CBC)

Arsenic 'hot spots' in Ndilo

According to a 1999 study, the arsenic concentrations in soil in Ndilo ranges up to more than 30 times the Canadian guideline limit for arsenic in residential areas.

"What would the response from everybody be if that hot spot was known to be at the corner of Mildred Hall School?," said Erasmus, referring to an elementary school in downtown Yellowknife. "What would it be if it was at St. Pat's (high school). Would it be any different?"

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 gold mines. Con mine is a former gold mine that flanks the city. The poisonous dust settled on the once-pristine land and lakes in and around Yellowknife. One teaspoon of it is enough to kill an adult.

A 1948 postcard shows and aerial view of Giant Mine including tanks, townsite, residences and buildings, only a few of which remain today. (NWT Archives/Busse/N-1979-052:1234)

Responsibility for off-site contamination

Though the hot spots were identified almost two decades ago, the territorial and federal governments only began discussing who is responsible for addressing off site contamination within the last year.

According to officials at Tuesday's meeting, the discussion was prompted by recent research that suggests much of the arsenic emitted by Giant in its early days, before any pollution controls were installed, is still in the soil and lake sediment in the area.

Previously the federal government took the position that it was responsible for containing the arsenic stored below ground — a job it estimates will cost upward of a billion dollars — and the territorial government was responsible for surface contamination. But the new research shows much of the arsenic that's in the area was emitted by the mine before the formation of a territorial government.

The contamination is also limiting development in Ndilo, which is located at the end of Latham Island in Great Slave Lake.

"We can't develop it and we can't afford to clean it up," said Joanne Black, who is with the Yellowknives Dene Lands and Environment Department. "My question here is who's responsible for it? I'm tired of this back and forth."

'Like a big, dark secret'

Black was also critical of health officials' refusal to warn people about the contamination. Though there are hot spots in the city, there are no signs warning of them.

"We have a lot of tourists that come to Yellowknife. I'm concerned for those tourists. I believe there are risks posed to tourists here and nobody's telling them. It's like it's a big dark secret."

Arsenic concentrations in Frame Lake, in the centre of the city, are more than 30 times the limit set for drinking water, yet there are no signs warning people of that. City and territorial health officials cannot agree who is responsible for warning people of the high levels.

Drinking water worries

The risks the mine poses to the city's drinking water was another issue raised at Tuesday's meeting of the Giant Mine Oversight Board. Since 1968 the city has been drawing its drinking water through an eight-kilometre underwater pipe to the Yellowknife River, upstream of Giant Mine.

The pipe is now deteriorating. The city estimates it will cost $20 million to replace it. As a cost saving measure, it's now considering a plan to retrofit its new water treatment plant to filter arsenic, and to draw drinking water from the Bay.

"One of the biggest concerns that the people of Yellowknife have facing them right now is their water source," said Yellowknife resident Mike Byrne.

"There was a reason that pipeline was built, and it's directly because of the impacts of that mine. That might be considered by the federal government to be an off-site problem, but it's considered by most of us, particularly those of us who have lived here for a lifetime, to be an on-site problem, that needs remediation and needs to be addressed."