Massive open-pit coal mines in British Columbia are leaching high concentrations of selenium into the Elk River watershed, damaging fish populations and contaminating drinking water. Now this pollution is flowing across the Canadian-U.S. border, threatening the quality of U.S. waters.

Paul Samycia was in a boat floating on British Columbia’s Elk River when he reeled in a strange-looking trout. One side of the fish looked like any other cutthroat trout — black speckles, orange belly, olive back. The other side of the fish had a hole in its face. Its gill cover, the flap on the side of its head, was partially missing. Samycia snapped a photo of the fish. For the last four years, Samycia, the owner of Elk River Guiding Company, a fly-fishing shop and outfitter based in Fernie, British Columbia, has been collecting photos of misshapen catches. Some have shortened gill plates. Others have snubbed noses, making them look like they swam into a rock. He and fellow guides have amassed nearly 40 photos. Samycia started noticing the deformities about 10 years ago, but the sightings are becoming increasingly common. Scientists have found substantial evidence that the cause is selenium, a trace element, leaching from coal mines in the Elk River watershed. A 2013 study found heightened selenium concentrations downstream of mines in the Elk Valley, and a 2014 report linked high selenium to a slew of damaging ecological consequences in the river, including malformations and reproductive failure in fish. Environmental groups now are raising concerns about harm to the ecosystem, ranging from the Elk River’s tributaries to waters downstream that cross into the United States. They also point to risks for human health in communities nearest to the mines, where selenium is contaminating drinking water. Meanwhile, tensions on both sides of the border are escalating: U.S. members of a binational water regulator sounded alarm bells last year, charging that Canadian members were suppressing scientific evidence related to the selenium pollution and its risks to the ecosystem and human health. The situation in the Elk has been called “a monumental selenium spill in slow motion.”

“We have one of the biggest selenium contamination issues in the world taking place in the Elk River,” says one biologist.

The destructive consequences of selenium pollution are well documented in North America. In the 1970s, agricultural runoff carried high selenium loads into a reservoir in California’s San Joaquin Valley, causing deformities in fish, reptiles, and birds. In the early 2000s, a vast mountaintop removal mining operation in West Virginia wrecked ecosystems in the Mud River. The problem in the Elk Valley is one of the most current and pressing examples. “We have one of the biggest selenium contamination issues in the world taking place in the Elk River,” says Erin Sexton, a biologist at the University of Montana who has been studying the region for nearly 20 years. It’s also one of the few cases to extend beyond borders. Now, scientists, conservation groups, industry, and government organizations from both Canada and the U.S. are trying to find a solution to one of the most complex, far-reaching selenium leaks either country has ever seen. The Elk River begins its journey in the Canadian Rockies and flows southwest for 140 miles through meandering oxbows before reaching Lake Koocanusa and the Montana border. Miners have excavated coal from the Canadian side of the watershed since the 1800s. In the past 40 years, large-scale, open-pit mining has come to dominate the region — a technique that involves stripping away layers of rock to get at coal deposits deeper in the earth.

A deformed cutthroat trout with its gill cover missing, found in the Elk River downstream of several major coal mines. Courtesy of Paul Samycia

Teck Resources, a Canadian mining company and the world’s second largest exporter of steelmaking coal, operates five open-pit coal mines within the watershed. These mines are some of the biggest in Canada. Together, they have the capacity to produce more than 21.7 million tons of metallurgical coal, an essential ingredient in producing steel from iron ore. To get at the coal, the company uses a technique called cross-valley fill, which in practice, looks a lot like mountaintop removal mining. Workers dig into hillsides, creating massive, terraced craters – holes so big they make 550-ton trucks look like toys. They separate the valuable coal from the unwanted rubble and dump the debris into waste piles throughout the valley. Scratching away at the surface day and night, the company has moved enough earth to flatten mountains, all while filling valleys with massive heaps of rock.

The piles of rubble are the source of the selenium problem. The trace element is naturally occurring and often accompanies the same geological formations as coal. When exposed to water and air, the element seeps out of rock and soil. In small amounts, selenium is necessary for biological function. At higher concentrations, however, it can become harmful. That’s the “paradox of selenium,” says Dennis Lemly, a retired selenium ecotoxicology expert who used to work as a researcher for the U.S. Forest Service and Wake Forest University in North Carolina. “Just a few times more than is required for normal health can be toxic.” In humans, chronic exposure to high selenium concentrations can cause nausea, fatigue, skin lesions, and neurological disorders. In other animals, the high levels of the element have been shown to cause liver damage, paralysis, and even death.

Selenium from coal mines along the Elk River and its tributaries travels more than 100 miles to Lake Koocanusa and into Montana. Erin Sexton / University of Montana

In Sparwood, a community of 3,490 people less than two miles from one of Teck’s mines, selenium in drinking water is reaching concerning levels. The town, located within the traditional territory of the Ktunaxa Nation, pulled one of its water wells offline last spring when selenium exceeded British Columbia’s drinking water standard of 10 micrograms per liter (selenium has been measured as high as 13.5 micrograms per liter, District of Sparwood records show). Last spring, Teck issued a statement warning landowners and farmers that “some mine-related constituents may be elevated.” Company testing found that selenium levels in four private wells exceeded provincial standards. Teck did not comment on the specific selenium concentrations in these wells. In an emailed statement, Chris Stannell, a company spokesperson, wrote that Teck has worked with governments, scientists, and First Nations to develop a management plan to address the selenium issue and is “dedicating significant resources to taking the steps necessary to achieve the objectives” laid out in that plan. In the meantime, Sparwood has two other wells to provide residents with clean drinking water, and Teck is now financing the construction of a new well to replace the tainted one, according to Sparwood Mayor David Wilks. The company has also been supplying bottled water to landowners whose private wells contain selenium levels exceeding British Columbia’s standard. British Columbia’s guideline for the protection of aquatic life is 2 micrograms per liter. The U.S. Environmental Protection Agency’s standard is 3.1 micrograms per liter in rivers and 1.5 in lakes. In the Elk Valley’s waters, selenium has been recorded at 50 to 70 micrograms per liter and in some cases, as high as 100 micrograms per liter.

Selenium levels were at least seven times higher in the Elk’s waters below mines than above them.

Those high selenium levels have had major repercussions on the watershed, Sexton, of the University of Montana, says. “The impacts are pretty extensive.” She and her colleagues conducted one of the first publicly available scientific studies showing that mining in the Elk Valley was detrimental to the river’s ecosystems. They collected ecological and water quality data in both the Elk and its neighboring watershed, the Flathead, which is considered relatively pristine. Sexton was baffled by the differences she saw. Selenium levels were at least seven times higher in the Elk’s rivers below mines than above them or in the Flathead, according to a 2013 report she published. The researchers also found reduced algae and invertebrate diversity in the Elk compared to the Flathead — a sign that selenium pollution was killing off sensitive species. Algae and invertebrates form the base of the food web in a river system. The selenium they accumulate in their tissues gets transferred up the food chain. In fish, the element tends to concentrate in females’ eggs, either killing juvenile fish or causing major birth defects. “Then all of a sudden the fish start disappearing, and in a couple of years, they’re all gone,” says Richard Hauer, a now-retired limnologist from the University of Montana who co-authored the study with Sexton. If you weren’t paying attention to the early warning signs, you might not notice a selenium problem until it’s too late, he says. In the Elk Valley, scientists have been paying attention to the warnings. A 2014 review by Lemly, the selenium ecotoxicology expert, details evidence of selenium poisoning in fish, including telltale signs such as twisted spines and cranial deformities. Environment Canada, the federal agency that oversees environmental enforcement, asked Lemly to conduct the review as part of its investigation into selenium pollution coming from Teck’s mines.

The Upper Fording River, a tributary where selenium levels are some of the highest in the Elk watershed. Courtesy of Lars Sander-Green / Wildsight

Lemly’s conclusions were unequivocal: Selenium levels in fish eggs and in surface waters are beyond those known to cause reproductive failure, he writes. In one of the Elk’s tributaries with the highest selenium concentrations, the Upper Fording River, he estimates that the element is killing nearly half of juvenile fish — more than 180,000 fish each year. The Upper Fording is also home to a genetically pure and distinct population of westslope cutthroat trout (Oncorhynchus clarkii lewisi), which is a species of special concern in Canada. Lemly calls the fish a sentinel species. “As they go, the aquatic system goes,” he says. The Upper Fording River is now closed to angling due to uncertainties about the viability of the cutthroat population. Meanwhile, questions remain about health risks linked to eating fish from river. “It’s not an area that’s being that well researched,” says Lars Sander-Green, an analyst with Wildsight, a local environmental group. Although not specific to the Elk watershed, a 2017 study conducted by the Canadian government found that subsistence fishermen and First Nations who eat fish caught downstream from sources of pollution have high selenium blood concentrations. Prolonged exposure to selenium in humans can cause selenosis, a condition linked to hair loss, skin lesions, neurological disorders, and intestinal problems. A few miles north of the Montana border, water from the Elk River spills into Lake Koocanusa and drifts across the U.S. border to Libby Dam. There too, selenium levels have increased. David Naftz, a hydrologist with the U.S. Geological Survey (USGS), is part of a team collecting samples of water, sediment, fish tissue, and eggs to better understand how selenium moves through the ecosystem. “The large amount of selenium coming into Lake Koocanusa is concerning,” Naftz says. There’s an influx of upwards of 14,000 kilograms per year — seven times more than Utah’s Great Salt Lake where USGS scientists reported selenium in the eggs of eared grebes and black-crowned night herons approaching levels that cause reproductive failure.

Regulating an environmental problem that affects international waters is extremely complicated, experts say.

Regulating an environmental problem that affects international waters is extremely complicated, experts say. In Montana, selenium standards are used to set discharge limits on permits. British Columbia employs a similar scheme. But conservation groups say the system on the north side of the border is broken. “We don’t have anything enforceable,” Wildsight’s Sander-Green says. Water quality guidelines in British Columbia are just that — guidelines, not laws. The government in 2013 ordered Teck to develop a water quality management plan to address the selenium issue. But according to company reports, Teck exceeded the selenium limits laid out in the plan six times in 2016 and another 20 times in 2017. A 2016 audit shows British Columbia’s provincial government granted Teck permits despite getting input from experts that the proposed selenium levels on those permits failed to protect the environment. U.S. commissioners from the International Joint Commission, a binational regulatory body that oversees shared Canada-U.S. waters, have also been critical. In a letter last year, they accused Canadian commissioners of minimizing scientific evidence on the valley’s selenium problem and its risk to aquatic and human life. Sexton says she finds the continuous lack of regulatory response to the selenium issue shocking. “As a scientist, you do this kind of work with the objective that the data you collect will inform environmental decision-making,” she says. But mining in the Elk Valley has steadily moved forward, despite mounting evidence pointing to the source of the problem. “From the big picture, it doesn’t appear that there is any regulatory response at all,” she says.

Biologist Erin Sexton conducts water sampling in the Elk River. Courtesy of Erin Sexton

The Canadian government is currently working on amendments to federal mining regulations that would place compliance limits on selenium discharges. British Columbia and Montana are also working to set selenium standards for Lake Koocanusa by 2020. Once established, the binational standard would be used to inform discharge limits on permits on both sides of the border. Until then, the Ktunaxa Nation Council, along with other First Nations’ leaders, are urging governments on both sides of the border to adopt more conservative interim standards for selenium in the lake. Teck plans to build six new waste treatment plants by 2030, but currently it has only one, and it had to be shut down at least twice because of technical problems since it came online in 2014. The company is considering other water treatment options too, such as systems that use microbes to remove selenium from water-filled pits. Some question whether those tools are capable of stopping such a massive selenium leak. These technologies have never been used at such a large scale, says USGS’s Naftz. Meanwhile, three companies have proposed new mines in the Elk River watershed. Currently in the early stages of environmental assessment, each new mines would add another 8 million tons of coal production to the valley. Sexton says the area needs a moratorium on mining until technologies have been proven capable of mitigating pollutants. By continuing to issue mining permits, regulators are only letting the problem get worse, she says. But others point out that stopping the mining isn’t necessarily going to make things better. “A moratorium on mining without a solution is just a moratorium,” Hauer says. The region needs a long-term solution to deal with such a massive, long-term problem.