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Climate Change Increases Rare Earth Elements In Colorado’s Snake River – High Country News – Know the West


A new study suggests that lower stream flows are the main culprit.

The confluence of the Upper Snake River (left), where the natural acid rock drainage of the local geology creates the characteristic rusty red coloration and pristine inflows of Deer Creek. Researchers here are studying how climate change releases more rare earth metals, often found in conjunction with acidic rock drainage, into rivers.

Courtesy of Garrett Street

The Snake River begins high in the Colorado Mountains, with springs near Loveland Pass. It winds downstream through rocky fields to a wet valley before finally joining the Blue River, which flows through Breckenridge and eventually empties into Dillon Reservoir. The river is important to the region: it provides drinking water to Denver and is a popular fly fishing spot.

But the snake could be heading for murky waters: according to a recent study, climate changes in its hydrology are releasing more rare earth elements. It’s a discovery that could have broader implications for water quality in the West.

The study, published last month in the journal Environmental sciences and technologies, discovered that higher levels of rare earth elements – a group of chemically similar metals – are found in Colorado’s water supply due to declining stream flows caused by drought and shrinking of the snowpack in winter.

Lower flow rates mean the metals are not as diluted as they have been in the past. While previous research has linked this phenomenon to increased zinc concentrations, the latest study is the first to look at rare earth elements.

“This is certainly the first (study) to link increasing concentrations of rare elements and hydrological changes due to climate change,” said study author Diane McKnight, professor of engineering at the ‘University of Colorado Boulder. “I don’t know of any other study that really examines what is the pattern of rare earth elements in a Snake River scale watershed, down to the drinking water supply.”

Rare earth elements are ubiquitous today, used in cell phones, hard drives and solar panels. They occur naturally as a group of 17 metallic elements. While studies show that they are toxic to small aquatic organisms and microbes, “we are not sure whether or not this extends to humans,” said lead author Garrett Rue, master’s student. at the University of Colorado Boulder. when the research was done. “These effects are understood at the bottom of the food chain, but it is very difficult to expand what this means for fish or more complex biological life.”

Rare earth elements are not considered a known toxicant by the Environmental Protection Agency; their concentrations are not monitored and no water quality standard has been set for them. Because they are often found in acidic mine drains with metals of concern, such as zinc and lead, it is difficult to isolate them and identify their effects. But their increasing use in medical products such as MRI tracers means rare earth elements are re-entering the ecosystem as wastewater, prompting a new effort to understand them.

Documenting the increasing concentrations of rare earth elements as well as recent climate-induced hydrological changes is important work, according to other experts in the field.

Gary Martinez surveys a Pennsylvania mine tunnel that was officially plugged in 2014. An 18 foot thick reinforced concrete bulkhead will help reduce the amount of heavy metals, such as zinc, flowing into the creek Peru and the upper sections of the Snake River. The researchers found that the region still contains high levels of rare earth metals.

Ben Trollinger / Summit Daily News via AP

“As things increasingly dry up, surface water and groundwater can be affected in the long term as water quality deteriorates,” said Kirk Nordstrom, a retired scientist from the ‘US Geological Survey which extensively studied acid mine drainage. (Nordstrom was not involved in the Snake River study.) “This is something hardly anyone discusses, but this article does. Rare earth elements are a hot topic these days and no one has data like the one in this article. “

The study, which used samples spanning nearly four decades, found a range of one to hundreds of micrograms per liter of elements throughout the Snake River. The mere fact that the researchers found concentrations high enough to warrant measuring in micrograms means that the river contains an unusually high amount of rare earth elements. Concentrations in large rivers are usually so low that they are measured in nanograms.

“They tend to be in the parts-per-trillion range, and we now see them in the parts-per-billion range,” Rue said. “This unit is 1,000 times higher.”

Scientists have also found that the elements accumulate in insects in waterways to levels similar to toxic lead and cadmium.

The highest concentrations were found near the headwaters and in areas receiving acid mine drainage from abandoned mines. Acid mine drainage occurs because rocks that contain certain minerals oxidize when exposed to air and water. The resulting chemical reaction creates sulfuric acid, which dissolves metals like iron and extracts rare earth elements from rocks.

“In Colorado, many of our major rivers originate in the mountains. And a lot of those mountains have been mined.

This occurs naturally across the West in areas rich in pyrite, but mining compounds the problem by disturbing large amounts of rock and soil. The study authors noted that more than 40% of the western headwaters are contaminated by acid mines or rock drainage, especially in states with a mining history like Colorado, Nevada, l ‘Utah, California and Montana.

“Acid mine drainage is a problem that people, whether they are aware of it or not, are surprisingly affected,” Rue said. “In Colorado, many of our major rivers originate in the mountains. And a lot of those mountains have been mined.

The Snake River passes the Keystone Ski Resort – where summer visitors occasionally fish for trout, which must be stocked as high zinc levels prevent them from surviving on their own in the river – before it flows into the Dillon Reservoir, a major water source water source for the city of Denver.

“These are legitimate concerns. And they should be treated as such, ”Rue said. “What happens upstream manifests itself downstream. “

Kylie Mohr is a writing intern for High Country News written from Montana. We welcome letters from readers. Email him at [email protected] or submit a letter to the editor. See our letters to the political editor.



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