Study: 95% of the selenium in Lake Koocanusa is from Canadian coal mines

A new study finds that Canadian coal mines contribute nearly all of the selenium found in Lake Koocanusa.

 For decades, coal mines along British Columbia’s Elk River have sent large amounts of selenium into Lake Koocanusa in northwest Montana.

Selenium is naturally occurring, but at high levels can harm fish reproduction.

Researchers wanted to know how much natural selenium came from the lake’s largest tributary, the Kootenai River.

Study author and U.S. Geological Survey Hydrologist Meryl Storb says, "Over the last decade, the Elk River is contributing 95% of the selenium into Koocanusa from those two sources.”

That’s striking because the Elk River accounts for a quarter of all waters flowing into Lake Koocanusa, but is contributing nearly all of the selenium.

Montana and British Columbia tribes are pushing U.S. and Canadian officials to shut the mines down.

1. Group sues the state for records on DOJ's communications with mining company
2. Bond is too small to cover cleanup costs for mines polluting Lake Kookanusa, report says
3. Tribes are cautiously optimistic about new deal on pollution from Canadian mines
4. The U.S. and Canada strike a deal over selenium pollution in Lake Koocanusa
5. Meeting on Lake Koocanusa selenium pollution set for Nov. 9