Lake Koocanusa needs a new limited selenium level

Featured Image: Lake Koocanusa, BC (Darren Kirby - Own work, CC BY-SA 3.0).

Last year's report from the Environmental Protection Agency confirmed what had been suspected for years. The Teck’s coal mining in the Elk River Valley (in British Columbia, Canada) is sending selenium downstream to Lake Koocanusa. Even though the lake is more than a hundred kilometers downstream of the coal mines, 95 % of the selenium comes from the Elk River.

The element leaches into the waterways from piles of waste rock at coal mines operated by Teck Resources and undergoing environmental assessments show there are concerns that the problem could get worse.

Even low concentrations of selenium allow the accumulation in the food chain because of the long (145 km) expansive still water. The degree of accumulation can be different depending on factors such as species and general water chemistry.

“Selenium can adversely impact a broad range of aquatic life including fish, and birds that eat aquatic life. High selenium levels can cause reduced growth and mortality in fish populations.” said the Montana Department of Environmental Quality (DEQ).

The influence of selenium in fish eggs is putting them at risk of birth defects and even complete reproductive failure.

On Oct. 30, the U.S. Environmental Protection Agency (EPA) approved Idaho’s Clean Water Act report, which lists the Kootenai River as impaired for selenium. Idaho’s sampling in 2019 found mountain whitefish with selenium levels in their reproductive organs that exceeded even EPA limits.

The concentration of selenium at the mouth of the Elk River started exceeding the British Columbia (B. C.) guideline in the early 1990s. Since then selenium has increased to a four times higher level than the B.C. guidelines.

There is a broad agreement among B.C., Montana and First Nations scientists that selenium should be limited to far less than the current B.C. guideline of two parts per billion, which is not enforceable. To prevent a dangerous build-up of selenium, the U.S. Geological Survey has prepared a detailed model that makes it clear that selenium must be limited to less than one part per billion- said Wildsight. The proposal, pitched through a review board with the DEQ, suggests a standard of 0.8 micrograms per litre (µg/L) of dissolved selenium.

“The proposed water column value for Lake Koocanusa is lower than the EPA’s national recommended criteria of 1.5 µg/L for lakes and reservoirs, but in alignment with the recommendation that, where possible, selenium standards should be established based on site-specific conditions” reads a news release from the DEQ.

The pollution limit is the result of years of work from the Lake Koocanusa Monitoring and Research Working Group, a cross-border committee. Six years ago, after Montana Fish, Wildlife & Parks found selenium levels were increasing in seven species of fish in the lake between 2008 and 2013.

B.C. and Montana have agreed to adopt a shared limit based on the outcome of the process. The Teck mining company that operates five coal mines in the Elk Valley and selenium scientific experts (First Nation scientists) and the government on both sides of the border are also collaborating and supporting the proposed standards.

While Montana is pushing ahead to adopt the selenium limit by the end of the year, it’s unclear when, if ever, the province will adopt the shared limit, Wildsight stated in a Sept. 30 media release.

“British Columbia has not yet selected a proposed water-quality objective for selenium, though they are committed to a science-based process informed by the best data available,” reads the statement.

Teck’s spokesperson is excusing: “ the company contributing data and technical input toward a process to develop a science-based site specific selenium criteria for the reservoir.” Furthermore the Teck has made ‘significant progress’ on the Elk Valley Water Quality Plan, building two water treatment facilities that are treating 17.5 million liters of water a day, to ramp up capacity to 47.5 million liters a day by 2021.

Meanwhile, Canadian mining companies are laying plans to expand existing open-pit coal mines and build new ones, which means pollutants like selenium will continue leaching from the growing piles of waste rock for decades.

Szilvia Kullai