Coyote Gulch's Colorado Water
The health of our waters is the principal measure of how we live on the land. -- Luna Leopold

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Tuesday, September 18, 2007

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Here's a background piece on Powertech's proposed uranium mining operation in Weld County, from The Loveland Reporter-Herald. From the article:

Company officials say if all the uranium is mined from the Centennial Project site, it would be enough fuel to serve the residential power needs of a city the size of Fort Collins for 150 years -- with no carbon emissions. "One pellet of uranium on the tip of your finger is equivalent to a ton of coal," said Richard Blubaugh, Powertech vice president of health, safety and environmental resources. "It really does make good sense." But [Robin Davis] wasn't convinced. So the 4-H leader, animal lover and renewable-energy advocate decided to fight what she worried would become a radioactive nightmare on her land and in the community's water supplies. "After I did my research, I said, 'Oh, we can't let this happen,'" Davis said...

Increasingly, mining companies, including Powertech, are choosing to extract uranium using a more modern, easier-on-the-land method called in-situ leaching. With conventional mining, workers remove rock from the ground, break it up and treat it to remove the uranium. But with in-situ leaching, crews can remove the uranium with far less ground disturbance. In-situ leaching involves pumping treated water into the uranium-laced deposits, which dissolves the mineral so the uranium can be pumped to the surface. The solution is then shipped to a processing plant to remove the uranium from the water. From there, the water is cleaned and returned to the area. But opponents say that's the problem: Pumping water back into the ground may contaminate water supplies with radioactive waste and loosen other minerals that may taint the water. None of the other 20-plus active uranium mines in Colorado extracts uranium with the in-situ leaching process, said Ron Cattany, director of the Colorado Division of Reclamation, Mining and Safety. Most uranium mines with active permits are in Montrose and San Miguel counties on the Western Slope, and all active ones are in compliance with their permits, Cattany said. Though there are no in-situ mines in the state, Cattany said Powertech would have to go through a rigorous permitting process to ensure its mines are safe and will not contaminate water supplies. "At this point, we feel pretty confident in the regulatory structure that's in place," Cattany said.

Thanks to Nonpoint Source Colorado for the link. More Coyote Gulch coverage here.

Category: 2008 Presidential Election

6:07:00 AM    

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Here's a look at a new method for tracking the spread of mercury in the environment, from The Environmental News Network. From the article:

With mercury polluting our air, soil and water and becoming concentrated in fish and wildlife as it is passed up the food chain, understanding how the potent nerve toxin travels through the environment is crucial. A new method developed at the University of Michigan uses natural "fingerprints" to track mercury and the chemical transformations it undergoes. A report on the work is published today in Science Express...

Because of such profound and irreversible effects on health and the environment, "it's very important to understand how and where mercury transforms into its most toxic forms and how it moves around in the environment, leading to human and animal exposure," said research fellow Bridget Bergquist, who is first author on the paper. "I have often dreamed of how useful it would be if we could mark individual atoms of mercury with an indelible fingerprint of key chemical reactions and use this fingerprint to follow them around in the environment," said co-author Joel D. Blum, who has been working on the problem for more than a decade. "This is precisely what we have been able to achieve with the experiments that we're reporting. Our work opens the door to an entirely new method for tracing mercury pollution and for investigating mercury behavior in the environment and in the food chains of humans and other animals."

Bergquist and Blum based their new tracking method on a natural phenomenon called isotopic fractionation, in which different isotopes (forms) of mercury react to form new compounds at slightly different rates, something like bicycle racers in the Tour de France. Some riders perform better in the mountainous stages of the race and are separated from the pack due to their strength; others distinguish themselves on the flat stages of race due to their superior speed. With mercury isotopes, it's mass, not athletic ability, that dictates their behavior -- in one type of isotopic fractionation, at least. In this mass-dependent fractionation (MDF), different mercury isotopes participate differently in chemical reactions, based on their masses. "While mass-dependent fractionation is a well-known phenomenon in lighter elements and forms the basis for how we determine such things as past climates on the Earth and dietary food chains of animals, mercury was thought to be too heavy for the signal to show up," said Blum, who is the John D. MacArthur Professor of Geological Sciences. But in this work, Bergquist and Blum show that mass-dependent fractionation can be used to track mercury. Because the process is observed naturally in fish as they grow, the mercury the fish excrete must have a different isotopic composition than the mercury they take in, so MDF may reveal how much mercury fish consume, how much they excrete and how it changes during the fishes' lifetimes. In the current work, the researchers exploited both MDF and another type of isotopic fractionation called mass-independent fractionation (MIF), in which isotopes segregate based not on absolute mass but on whether their masses are odd or even. Bergquist and Blum discovered that this type of fractionation occurs only in reactions involving sunlight, such as those that take place in surface waters and result in methylmercury being detoxified and released to the atmosphere. Mass-independent fractionation of mercury and other heavy elements had been predicted but never carefully documented in nature. By combining two methods that provide distinct isotope signatures, Bergquist and Blum came up with a tracking tool that is more powerful than either one alone...

Using the method in this way illustrates its potential for much wider application, Blum said. "One example is a complementary study that we reported at a recent scientific meeting." In that study research fellow Abir Biswas, working with Bergquist and Blum, found that mercury in coals from various coal-producing regions around the world vary in their mass-dependent and mass-independent isotopic composition. "This suggests that we may be able to use the mercury isotope studies to distinguish different sources of mercury to the atmosphere, which has far-reaching practical applications," Blum said. "In short, this entirely new approach to studying mercury sources, mobility and toxicity in the environment paves the way for a wide range of studies that should enhance our understanding of this important toxin in the environment."

Thanks to Nonpoint Source Colorado for the link.

Category: Colorado Water

5:53:46 AM    

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Here's an report on the new outlet for Carter Lake from The Longmont Daily Times-Call. From the article:

Northern Colorado Water Conservancy District has been drawing down the water in Carter Lake this summer so workers could build a new outlet at Dam No. 1 on the reservoir's southeast side. The lake has about 20,000 acre-feet of water in it now, but has the capacity to hold about 112,000 acre-feet. That means Carter Lake is at about 20 percent of capacity, or about 36 feet below its highest water levels...

...because of that constant demand on the almost 60-year-old outlet -- about 500,000 customers rely on it either for part or all of their water, [Carl Brouwer, Northern Colorado Water Conservancy District project manager] said -- the district can only shut down the outlet for a few days at a time to make necessary repairs. Once complete, the new outlet will serve as the lake's primary outlet for most of the year, Brouwer said...

When it becomes "economically attractive," officials may add a small hydroelectric station to the new outlet to harvest the 2.5 megawatts of energy it produces, Brouwer said. The new outlet will run through an 800-foot tunnel about 200 feet south of the existing outlet on Dam No. 1. The north boat ramp near the marina remains open, but the other two ramps have closed. Water district officials say Carter's water levels should be back to normal next summer once construction is complete in the spring.

Category: Colorado Water

5:39:43 AM    

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