Evidence of selenium transport from Elk River Valley, Canada to the Columbia River
Selenium is an essential nutrient with a narrow gap between enough for life and too much for life. Mining operations have been linked to releasing selenium into rivers and streams, where it can accumulate in aquatic ecosystems and disrupt the development of egg-laying organisms like fish and birds. Recent research shows that selenium travels farther from the Elk River Valley than previously documented and may pose risks to aquatic life in the transboundary Columbia River.
Key Findings of Study
- Selenium from coal mines in the Elk River Valley persists approximately 360 miles to the Columbia River upstream of the United States and Canadian border, which is farther than previously documented.
- Over about 15 years, selenium concentrations have been increasing downstream of the mines on the Elk, Kootenay, and Columbia Rivers, which means that potential risks to aquatic life are also increasing.
- Most of the selenium in the Columbia River can be attributed to coal mines that are approximately 360 miles upstream. Other industrial and natural sources in the Columbia River watershed contribute less selenium than the coal mines.
Selenium in the Elk River Valley, Canada
Previous studies have shown that mining in the Elk River Valley, Canada has increased concentrations of selenium in Lake Koocanusa, a transboundary reservoir located in northwestern Montana and southwestern British Columbia. Through multiple lines of evidence, current research shows that elevated selenium concentrations were found downstream from the reservoir in the Kootenay River and in the Columbia River near the Washington-British Columbia border. By comparing selenium concentrations, loads, and trends in concentrations at five Kootenay River sites downstream from the mines to one site unaffected by mining in the Kootenay River, researchers found that elevated selenium concentrations were linked to coal mining activities upstream.
Environmental risks of elevated selenium concentrations and transport
Selenium concentrations in Lake Koocanusa have been detected at concentrations that consistently exceed water-quality criteria put in place to protect aquatic life. Selenium is a naturally occurring element found in rocks and soil, but mining operations like in Elk River Valley, Canada accelerate the weathering of selenium into the environment. This accelerated release can lead to concentrations in downstream waters that are higher than areas without mining.
Long-distance transport of selenium illustrates how mining operations in the Elk River Valley may affect aquatic health downstream as far as the Columbia River. Declining fish populations in the Columbia River fish populations have historically been attributed to changing land use practices, such as dams, but this research suggests selenium may also pose risks to aquatic life. Currently, selenium concentrations at the Columbia River sites do not regularly exceed US water quality standards and Canadian water quality guidelines. However, results of this study show that selenium can be transported far downstream of the Elk River Mines and that concentrations in the Columbia River are increasing, which indicates that potential risks to aquatic life are also increasing.
Selenium is an essential nutrient with a narrow gap between enough for life and too much for life. Mining operations have been linked to releasing selenium into rivers and streams, where it can accumulate in aquatic ecosystems and disrupt the development of egg-laying organisms like fish and birds. Recent research shows that selenium travels farther from the Elk River Valley than previously documented and may pose risks to aquatic life in the transboundary Columbia River.
Key Findings of Study
- Selenium from coal mines in the Elk River Valley persists approximately 360 miles to the Columbia River upstream of the United States and Canadian border, which is farther than previously documented.
- Over about 15 years, selenium concentrations have been increasing downstream of the mines on the Elk, Kootenay, and Columbia Rivers, which means that potential risks to aquatic life are also increasing.
- Most of the selenium in the Columbia River can be attributed to coal mines that are approximately 360 miles upstream. Other industrial and natural sources in the Columbia River watershed contribute less selenium than the coal mines.
Selenium in the Elk River Valley, Canada
Previous studies have shown that mining in the Elk River Valley, Canada has increased concentrations of selenium in Lake Koocanusa, a transboundary reservoir located in northwestern Montana and southwestern British Columbia. Through multiple lines of evidence, current research shows that elevated selenium concentrations were found downstream from the reservoir in the Kootenay River and in the Columbia River near the Washington-British Columbia border. By comparing selenium concentrations, loads, and trends in concentrations at five Kootenay River sites downstream from the mines to one site unaffected by mining in the Kootenay River, researchers found that elevated selenium concentrations were linked to coal mining activities upstream.
Environmental risks of elevated selenium concentrations and transport
Selenium concentrations in Lake Koocanusa have been detected at concentrations that consistently exceed water-quality criteria put in place to protect aquatic life. Selenium is a naturally occurring element found in rocks and soil, but mining operations like in Elk River Valley, Canada accelerate the weathering of selenium into the environment. This accelerated release can lead to concentrations in downstream waters that are higher than areas without mining.
Long-distance transport of selenium illustrates how mining operations in the Elk River Valley may affect aquatic health downstream as far as the Columbia River. Declining fish populations in the Columbia River fish populations have historically been attributed to changing land use practices, such as dams, but this research suggests selenium may also pose risks to aquatic life. Currently, selenium concentrations at the Columbia River sites do not regularly exceed US water quality standards and Canadian water quality guidelines. However, results of this study show that selenium can be transported far downstream of the Elk River Mines and that concentrations in the Columbia River are increasing, which indicates that potential risks to aquatic life are also increasing.