Almost one year after an unprecedented spill from a mine tailings pond in Canada’s largely pristine province of British Columbia, its government has given the green light for the mine to reopen — worrying environmentalists who say a number of other northern B.C. copper and gold mines are in various phases of approval, and could threaten downstream fishing communities in southeastern Alaska.

The provincial government on Thursday approved a restart of Imperial Metal’s Mount Polley mine, which has been closed since its waste dam failed last August and released 6.6 billion gallons of toxic tailings including arsenic, lead and nickel into salmon-producing lakes and streams of the Fraser River watershed.

Residents of southeastern Alaska, many of whom depend on fishing and tourism for their livelihoods, expressed concern at the announcement.

“The British Columbia and Canadian governments seem to be glossing over the Mount Polley disaster by ignoring recommendations of mining experts who studied the dam failure and warned that the province should stop allowing the same risky tailings dam technology,” said an emailed statement from Heather Hardcastle, a commercial fisherman from Juneau, Alaska, and campaign coordinator for Salmon Beyond Borders.

Scientists at University of Northern British Columbia (UNBC) — Samuel Albers, manager of the Quesnel River Research Centre; Philip Owens, a professor of environmental science; and Ellen Petticrew, a professor of geology — said they had already been doing research before the spill at Mount Polley, and had baseline data.

Not only did they observe elevated copper levels, Albers said, they also saw that sediment from the tailings spill was moving out of Quesnel Lake into the river that drained it — the same type of toxic pollution migration that communities in southeastern Alaska were worried about.

The researchers said it was too early to tell if the toxins were being absorbed into the food chain, and added that they were applying for grants to undertake further studies.

Residents in some communities in the area are worried about potential health effects from eating fish exposed to toxins in the mine tailings, said Paula Dobbyn, director of communications for Trout Unlimited, a national conservation organization.

Imperial Metals received approval in June to open another large mine in northwestern B.C. called Red Chris, which will use the same type of tailings pond and dam as Mount Polley, according to Hardcastle.

Red Chris, located in the headwaters of the Stikine River, is larger than Mount Polley and was constructed using the same standards of design and oversight that were in place when Mount Polley’s dam collapsed, Hardcastle said.

The approval of Red Chris, Mount Polley — and the other eight mines that appear set to be approved — have worried communities in southeastern Alaska who share watersheds with the B.C. mines and feel their fishing industry could be jeopardized.

“British Columbia is in an aggressive mine development push,” Dobbyn said.

Hardcastle said Alaskans, who would be forced to take on a large share of the risks from these mining projects but none of the economic benefits, need a voice in the process.

“These are some of the largest gold and copper mines in the world, in the headwaters of the largest salmon producing region of the world,” Hardcastle said. “Those of us on this side of the border are pushing very hard to protect our downstream communities.”

The state of Alaska has been involved to some degree in the approval process for three of the mines — Tulsequah Chief, Galore Greek and KSM — but many Alaskans said despite that they felt left out of the process.

“We feel that B.C. and Canada are obligated to address our concerns through the Boundary Waters Treaty — a powerful treaty that said neither country shall pollute on either side of the border,” Hardcastle said.

“If there is a high likelihood that pollution will occur that country that could be polluting is obligated to address the concerns of the downstream nation,” Hardcastle said.

The problem is that invoking the treaty requires Canada and B.C. to activate the commission, which they are not likely to be in favor of, Hardcastle said. Still, environmental activists in Alaska will keep trying to get U.S. and Canadian officials to listen to their concerns.

“Our way of life is centered on salmon,” Hardcastle said, adding that fishing and tourism in southeast Alaska are billion-dollar industries.

Commercial fishing is the top industry for private employers in the state, said Dale Kelley, executive director of the Alaska Trollers Association.

“We are very concerned about toxic metals and acid bleaching and their potential effects on fish — even without an epic problem like Mount Polley," Kelley said.

Sarah O’Neal, an independent freshwater ecologist, said she’s been working on salmon rivers on the West Coast for 20 years, and B.C. is “sort of a line in the sand because there are still strong, healthy salmon runs there, but the wave of extinction is slowly marching north.”

The mining development "could be a huge contributing factor in the demise of salmon in that region,” O’Neal said.

Some of the toxins generated in the mining process, and stored in tailings ponds like that of Mount Polley, are extremely harmful to fish even in small quantities, O’Neal said. The tailings become acid-generating when parts of the ore are dug up and exposed to air and water, he added.

“In small quantities, with copper tailings at 2-10 parts per million — or the equivalent of two drops in an Olympic size swimming pool — can affect salmon’s ability to smell, recognize prey, sniff out siblings so they don’t make mutant babies, and find their way home,” O’Neal said.

Most of the mines in B.C. will be large copper mines, although some would be gold mines, according to David Chambers, a mining expert and president of the Center for Science in Public Participation.

Copper mines are more worrisome to downstream communities because the waste they move and store is potentially acid-generating, meaning it can produce acid that releases metals into the water which are toxic at low levels, Chambers said.

Typically the copper would be about 0.3 percent of the mined rock and ore, and 99.7 percent would be waste or tailings, Chambers said. The finely ground rock containing potentially toxic metals and water would then be stored in the tailings pond.

“I can’t say there’s going to be problems that kill fish, but they can’t say there won’t — and that raises the level of risk,” Chambers said. “The projects being proposed are not following what engineers or regulators would say are best practices.”

To make matters worse, the tailings pond dams in these mines are meant to last “in perpetuity,” Chambers said, adding that "failure associated with this type of (tailings) dam is fairly common.”

A better way to store the mining waste would be dry closures, which would be possible for the B.C. mines, Chambers said. Whereas tailings ponds mix the waste rock with water that is stored behind a dam, dry closures — or dry stacking — involve removing the water from tailings and then stacking the dry waste rock.

The tailings storage facility at Red Chris mine has been the subject of three independent reviews, including one commissioned by the Tahltan Central Council to assess seepage and design considerations. Imperial Metals did not respond to a request for comment on why it decided to use the same type of tailings pond that failed at Mount Polley.

Dobbyn said many post-spill recommendations such as using a dry closure instead of another tailings pond on Mount Polley were ignored, and that failing to head warnings about the lack of structural integrity of the type of tailings pond used at Red Chris and Mount Polley could be disastrous.

“After the Mount Polley spill, the province commissioned a study to find out what happened, which came out in January with the top recommendation being that no new mines should have tailings dam with water in them,” Dobbyn said.

“Within days of that report coming out the province gave approval to Red Chris — totally ignoring the Mount Polley report,” Dobbyn said. “It’s a loaded gun waiting to go off.”