Diane McKnight

Precious waterways: how contaminated mountain streams could power American-made technology

Jeff Zehnder — Mon, 05 Jan 2026 17:20:21 +0000

Precious waterways: how contaminated mountain streams could power American-made technology Jeff Zehnder Mon, 01/05/2026 - 10:20

Most people have never heard of neodymium, a strong, silvery rare-earth metal, yet almost all of us carry around a little bit of it in our pocket every day.

“Your cell phone, your computer — all of these things run on lanthanides, a series of 14 elements that are relatively heavy metals,” Institute of Arctic and Alpine Research (INSTAAR) geochemist and CU professor Tom Marchitto said.

Though these elements are rare, they are found in unusually high concentrations in certain streams here in Colorado. The phenomenon occurs along Colorado’s “mineral belt,” where acidic waterways pick up metals trapped in bedrock. With Marchitto’s help, INSTAAR biogeochemist and CU distinguished professor Diane Mcknight and collaborators have spent the past decade investigating this process at old mining sites and natural “acid rock” deposits around the state.

Now, their efforts could lead to another exciting discovery. McKnight and Marchitto are part of a new $2.8 million project, funded by the U.S. Department of Energy and led by the University of Missouri, that seeks a method for extracting rare earths from acid rock drainage for industrial uses.

The project comes at a fortuitous moment. Recently, the Trump administration has sought ways to decrease America’s reliance on China for rare earths by subsidizing U.S. production. At the same time, metal contamination from acid rock drainage is increasing in Colorado and causing environmental harm. If the new project is successful, it could improve water quality by removing metal while simultaneously producing essential raw materials for personal electronics, electric vehicles and military technologies.

“Improving water quality impacts associated with acid mine and rock drainage is really expensive,” McKnight said. “If there’s a valuable commodity that could be recovered through that process, it could change the equation.”

Master's students Athena Bolin and Adam Odorisio collect water samples from a creek near Aspen. (courtesy photo)

An unexpected finding

�� a decade ago, rare earth metals weren’t yet on Diane McKnight’s radar. For years, she and her students had characterized processes leading to metals like copper and zinc leaching into waterways along Colorado’s mineral belt. But, a serendipitous accident that led to a further discovery.

“A colleague happened to put my student, Garrett Rue’s, samples at the end of a run testing for rare earths,” McKnight said. “Afterward, he got in touch with Garrett and asked, “where are these samples from? There’s 200 micrograms per liter of neodymium!”

Later, Rue published a paper in Environmental Science and Technology based on these findings. In the years since, a steady stream of passionate students have scrounged funding to continue investigating the presence of rare earths in mountain watersheds. Marchitto has supported these efforts through his lab’s powerful mass spectrometer, capable of measuring trace amounts of metals in water samples.

One insight from this work is that metal concentrations in Colorado are increasing over time as warming summer temperatures thaw previously frozen sites containing acid-forming bedrock. This result is alarming from an ecological perspective. If metal concentrations climb too high, they can kill aquatic species, as evidenced by one mountain lake that washed up hundreds of dead fish this summer.

But, these increased concentrations may also present an opportunity. That’s according to Baolin Deng and Pan Ni, two distinguished researchers at the University of Missouri’s Missouri Water Center, who are now working to unlock an efficient process capable of extracting rare earths from acid rock drainage.

Molecular puzzle pieces

For the proposal to work, the process must be both efficient and selective. The inputs required must be low enough to make the method economically viable, while the outputs must be concentrated enough to provide a high-quality source of rare earth metals.

That’s why Deng and Ni have decided to target these elements at a molecular level. They propose creating ion-imprinted polymers, made from seafood byproducts. These polymers will act like jigsaw puzzle pieces. Most molecules will bounce right off them, but the targeted element will fit perfectly into the ion-imprinted cavity, allowing the researchers to conserve target elements and filter out the rest.

Designing these polymers is a monumental task. To increase their chances of success, the researchers will deploy artificial intelligence to help them iterate and refine.

“These elements are like twin brothers when it comes to telling them apart,” Ni said. “Maybe one weighs just a little more than the other. It’s incredibly challenging to differentiate them, but Professor Deng and our research team have proven it’s possible. Now, AI will further enhance the selectivity of our material.”

While the University of Missouri team is busy refining polymers, Marchitto, McKnight, and a to-be-hired PhD student will have their work cut out for them in Colorado. The team will work to identify potential sites for extraction, while also continuing to probe questions about the geochemical processes activated in these waterways.

“We’re also interested in the natural aspects of acid rock drainage that haven’t been explored much, like ‘what controls rare earth concentrations? And, ‘how are they precipitating out in the stream bed?’” Marchitto said. “Knowing more about the fundamentals of the geochemistry will inform what kind of recovery efforts can be used. It’s all connected.”

If you have questions about this story, or would like to reach out to INSTAAR for further comment, you can contact Senior Communications Specialist Gabe Allen at gabriel.allen@colorado.edu.

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Students study metal contamination in Colorado waterways

Jeff Zehnder — Fri, 12 Sep 2025 17:37:24 +0000

Students study metal contamination in Colorado waterways Jeff Zehnder Fri, 09/12/2025 - 11:37

Jeff Zehnder

Collecting water samples in the field.

In the most beautiful places in Colorado, hazards to aquatic life lurk in the water.

A team at the �� is studying heavy metal pollution in a watershed near Aspen. Their efforts have a dual goal: contributing to efforts to clean up the area, and studying the potential of recovering some of those metals, including rare earth elements, from other similarly polluted streams.

“We gave a presentation to the public, and when you mention valuable minerals in Aspen, ears perk up,” said Adam Odorisio, a master’s student in environmental engineering.

The issue concerns tributaries of Lincoln Creek, which feed into a large reservoir above Aspen. The metals in the water represent more than just pollution. The potential for recovering and utilizing the rare earth elements found in natural and mine acidic drainage is an area of active research, driven by increasing demand for these elements in many industries, such as electronics manufacturing.

Metals often leach from old mines, a process called acid mine drainage. In the case of Lincoln Creek, the primary contamination is a natural phenomenon, according to Athena Bolin, a 2025 environmental engineering master of science graduate student working on the project.

“The leaching of metals and rare earth elements can be caused by humans when they excavate and expose rock formations, but it can also occur naturally. This happens when mineral-rich rock weathers and the resulting acidic water leaches metals from rocks along its flow path. Both processes can cause significant environmental pollution,” Bolin said.

Bolin and Odorisio are part of Professor Diane McKnight’s research team and CU Boulder’s Institute of Arctic and Alpine Research, which have been studying the problem. The contamination has caused significant fish kills in the area, and the team has determined that metal concentrations are increasing significantly, a trend that is evident both seasonally and over many years in multiple watersheds in the Colorado Rocky Mountains as summers have become warmer.

“We analyzed a sediment core from Grizzly Reservoir,” Odorisio said. “The reservoir was built in 1936, and the core shows the contamination is getting worse. The thought is the world is heating up, which is melting sub-surface permafrost more quickly, which flows through the ground and eventually reaches the surface.”

The study involves taking on-site samples of water from a small tributary, a mine outflow, and the main stream, as well as a type of sediment called flocculant material, and aquatic insects, bringing them back to the laboratory, and using analytical methods to determine elemental concentrations.

Sediment core processing in the lab.

“One of the things we've found in the samples is copper is more elevated. That causes a lot of environmental damage. It can be extremely harmful to fish. They can't breathe. They suffocate,” Odorisio said.

As regional officials investigate the best solutions for Lincoln Creek, McKnight’s group is also working with colleagues to see if it would be cost-effective to recover the metals and rare earth elements for sale at similar sites.

Damaging heavy metal drainage occurs at locations across Colorado and regions with mining history. Being able to generate revenue from cleanup presents a unique opportunity in locations that often present complex remediation challenges.

“This takes place in a very remote wilderness area above 11,000 feet. A standalone recovery operation would not be financially viable. However, if recovery from the small tributaries and mine outflows were to happen concurrently with remediation, the income from the operation could help offset the cost of cleanup,” Bolin said.

Regardless of the eventual outcomes, Odorisio said the research and public response have been a positive experience in an area of study that can be discouraging.

“There’s a lot of doom and gloom in environmental engineering,” Odorisio said. “It’s just the nature of the job. Here we have two different motivations. We have the potential utility of it, recovering rare earth elements, and understanding how to make creeks like this one more environmentally friendly sites.”

In the most beautiful places in Colorado, hazards to aquatic life lurk in the water. A team at the �� is studying heavy metal pollution in a watershed near Aspen. Their efforts have a...

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Climate change causing increase in metals concentrations in streams

Anonymous — Fri, 24 May 2024 22:45:43 +0000

Climate change causing increase in metals concentrations in streams Anonymous (not verified) Fri, 05/24/2024 - 16:45

Diane McKnight's alpine stream research is highlighted in a new article published in the Aspen Times.

The piece focuses on newly published research demonstrating climate-driven increases in stream metal concentrations in the Colorado Rocky Mountains, including Lincoln Creek above Aspen.

McKnight, a distinguished professor in the Environmental Engineering Program and the Institute of Arctic and Alpine Research, is an expert on aquatic ecology and the interactions between hydrologic, chemical and biological processes in aquatic systems.

McKnight has been measuring the pH levels of the upper Snake River in Summit County for decades. On a recent trip with students, a stream that usually had a pH level of about 4 measured 2.75, meaning the acidity had greatly increased.

“I said: Wait, the probe must be wrong, the probe must be broken,” she said. “Guess what, the probe was not broken. … The public should be aware the world is changing, and there are surprises.”

Read the full article at the Aspen Times...

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McKnight named a CU Distinguished Professor

Anonymous — Wed, 01 Dec 2021 18:44:13 +0000

McKnight named a CU Distinguished Professor Anonymous (not verified) Wed, 12/01/2021 - 11:44

Jeff Zehnder

Diane McKnight is being recognized with the highest honor bestowed upon faculty in the University of Colorado system: Distinguished Professor, which is awarded to faculty for exemplary performance in research, teaching, and service.

A professor in the Department of Civil, Environmental and Architectural Engineering; the Environmental Engineering Program; and the Institute of Arctic and Alpine Research, McKnight has spent her career studying ecological, biogeochemical and hydrologic processes in lakes, streams and watersheds, primarily in polar and mountain regions.

“I’ve been interested in hydrology and ecology since I was in college in the ’70s,” McKnight said. “It’s fascinating work and directly impacts our understanding of water quality and the influence of climate and hydrology.”

Her research has dramatically expanded knowledge about the relationship between natural organic matter and heavy metals in streams and lakes and led to her election to the National Academy of Engineering in 2012.

Much of her field work has been in extreme environments, especially polar regions – she has been to Antarctica more than two dozen times.

“The lessons that we learn in Antarctica get plugged in more broadly. The algae growing in streams there are very similar to algae growing in Colorado, but we can understand more clearly what’s happening there because there is no signal coming in from plants in the meadow or in the forest because there aren’t any meadows or forests,” she said. “They’re like naked streams. We can learn about fundamental processes.”

McKnight is one of the founding principal investigators of the McMurdo Dry Valleys Long Term Ecological Research Program in Antarctica, and she serves as chair of the National Science Foundation’s LTER Science Council.

“As we think about green engineering for green infrastructure, people are putting more value on sustaining rivers to help deal with floods in cities and various pollution issues. These ecosystem concepts are also very relevant to dealing with hazardous algal blooms,” she said. “There’s a realization that some of the water challenges can’t just be addressed by treating drinking water at the utility plant. We need a more holistic approach, a bigger view.”

McKnight earned her PhD in environmental engineering at the Massachusetts Institute of Technology in 1979 and spent 17 years at the U.S. Geologic Survey, conducting field and laboratory research, before joining CU Boulder in 1996.

“I was at the USGS and had grad students working in my lab from CU Boulder, Colorado State, and the School of Mines. I really wanted to teach stream ecology. It’s an exciting field and the students are excited, too,” she said.

She was one of the founding faculty members of CU Boulder’s Environmental Engineering Program when it began in 1998 and has been part of its growth as an important discipline in the College of Engineering and Applied Science.

“We have as many students in a single environmental engineering class now as we had in the whole program when it started. It’s to CU Boulder’s great credit that this program has been supported and evolved,” she said. “I am glad to be part of how we deliver this curriculum and train our students. I am so indebted to my colleagues at INSTAAR and in environmental engineering who have been very supportive.”

Although McKnight is in the middle of a semester-long sabbatical, conducting remediation research on the hydrology of the Florida Everglades, she is eager to be back on campus for the spring 2022 semester.

“It’s a great privilege to teach a class and to advise and mentor students. You’re providing scope, being open to their ideas and also helping them stay focused and to take setbacks in stride,” she said. “They are so motivated and unafraid. It’s inspiring.”

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