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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 �鶹��Ƶ 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.”