Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Elevated zinc concentrations in Colorado waterway likely a result of climate change

16.12.2010
Rising concentrations of zinc in a waterway on Colorado's Western Slope may be the result of climate change that is affecting the timing of annual snowmelt, says a new study led by the University of Colorado at Boulder.

The study focused on the Snake River watershed just west of the Continental Divide near Keystone, Colo., where CU-Boulder researchers have observed a four-fold increase in dissolved zinc over the last 30 years during the lowest water flow months, said Caitlin Crouch. Crouch, a master's degree student who led the study, said the high levels of zinc affect stream ecology, including deleterious effects on microbes, algae, invertebrates and fish.

The team speculated the increased zinc concentrations may be tied to changes in groundwater conditions and stream flow patterns caused by climate change and the associated snowmelt that has been peaking two to three weeks earlier than normal in recent years, largely because of warming air temperatures. The result is lowered stream flows and drier soils along the stream in September and October, which increases metal concentrations, said Crouch.

"While most of the talk about climate change in western waterways is about decreasing water quantities, we are evaluating potential climate influences on water quality, which is a whole different ball game," she said.

Crouch gave a presentation on the subject at the fall meeting of the American Geophysical Union held in San Francisco Dec. 13-17. The study was co-authored by Professor Diane McKnight of CU-Boulder's civil and environmental engineering department.

The zinc in the Snake River watershed is primarily a result of acid rock drainage, or ARD, which can come from abandoned mine sites along rivers or through the natural weathering of pyrite in the local rock, said Crouch. Sometimes enhanced by mining activity, weathering pyrite forms sulfuric acid through a series of chemical reactions, which dissolves metals like zinc and carries them into the groundwater.

McKnight, also a fellow of CU-Boulder's Institute of Arctic and Alpine Research, said there are nearly 2,000 miles of waterways in Colorado affected by ARD.

One of the most noticeable impacts of ARD in the Upper Snake River drainage is on the fishery downstream, said Crouch, a graduate student in CU-Boulder's Environmental Studies Program. Rainbow trout populations in much of the river are not self-sustaining because of ecologically harsh stream conditions, and the waterway requires stocking several times a year.

The elevated zinc in the Snake River comes from several ARD sources, said Crouch. Crouch's study site -- where an increasing trend in zinc concentrations is sustained by groundwater discharge -- is above the Peru Creek tributary to the Snake River, where natural pyrite weathering is thought to be the main source of ARD. Peru Creek is largely devoid of life due to ARD from the abandoned Pennsylvania Mine and other smaller mines upstream and has been a target for potential remediation efforts.

McKnight said another factor involved in rising zinc levels in the Snake River watershed -- which runs from the top of the Continental Divide to Dillon Reservoir -- could be the result of the severe 2002 drought in Colorado. The drought significantly lowered waterways, allowing more pyrite to be weathered in dry soils of the watershed and in wetlands adjacent to the stream.

As part of her study, Crouch measured zinc concentrations in an alpine tributary of the Upper Snake River. She found that zinc concentrations there were 10 times higher than in the main stem of the waterway and correlated with increased sulfate, so-called "hard water" containing calcium and magnesium, and a variety of metals.

"This supports our contention that the increasing zinc concentrations we are seeing in the watershed are driven by the acceleration of ARD," Crouch said. "One of the things I still am trying to parse out is whether metals like zinc are coming from one discrete source or are being diffused into the watershed from the groundwater beneath."

Cleaning up abandoned, polluted mines like the Pennsylvania Mine remains a problem largely because of liability issues since the mine owners who normally would be responsible for the mine cleanup are long gone. The Environmental Protection Agency has begun an agency-wide effort to reduce barriers to the cleanup of abandoned mine sites by local environmental groups and volunteers.

In the case of the Pennsylvania Mine, the Snake River Task Force is working with partners like the Keystone Ski Resort, the Keystone Center, Trout Unlimited, the Northwest Colorado Council of Governments, Summit County, the Colorado Department of Public Health and Environment, the EPA and the Blue River Watershed Group.

Seven CU-Boulder graduate students have produced master's and doctoral theses under McKnight on environmental issues related to the Snake River watershed. Copies of the studies have been provided to the Snake River Task Force to help assess the current and future stream chemistry and biology in the area.

Caitlin Crouch | EurekAlert!
Further information:
http://www.colorado.edu

More articles from Studies and Analyses:

nachricht Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>