'Hydraulic fracturing' mobilizes uranium in marcellus shale

'Fracking' mobilizes uranium in marcellus shale
UB Professor Tracy Bank and her colleagues have found that hydraulic fracturing or "fracking" of Marcellus shale causes naturally occurring uranium to be released, raising additional environmental concerns. Credit: UB/Douglas Levere

Scientific and political disputes over drilling Marcellus shale for natural gas have focused primarily on the environmental effects of pumping millions of gallons of water and chemicals deep underground to blast through rocks to release the natural gas.

But University at Buffalo researchers have now found that that process -- called hydraulic fracturing or "fracking"-- also causes that is naturally trapped inside Marcellus shale to be released, raising additional environmental concerns.

The research will be presented at the annual meeting of the Geological Society of America in Denver on Nov. 2.

Marcellus shale is a massive rock formation that stretches from New York through Pennsylvania, Ohio and West Virginia, and which is often described as the nation's largest source of natural gas.

"Marcellus shale naturally traps metals such as uranium and at levels higher than usually found naturally, but lower than manmade contamination levels," says Tracy Bank, PhD, assistant professor of geology in UB's College of Arts and Sciences and lead researcher. "My question was, if they start drilling and pumping millions of gallons of water into these underground rocks, will that force the uranium into the soluble phase and mobilize it? Will uranium then show up in ?"

To find out, Bank and her colleagues at UB scanned the surfaces of Marcellus shale samples from Western New York and Pennsylvania. Using sensitive chemical instruments, they created a chemical map of the surfaces to determine the precise location in the shale of the hydrocarbons, the containing natural gas.

"We found that the uranium and the hydrocarbons are in the same physical space," says Bank. "We found that they are not just physically -- but also chemically -- bound.

"That led me to believe that uranium in solution could be more of an issue because the process of drilling to extract the hydrocarbons could start mobilizing the metals as well, forcing them into the soluble phase and causing them to move around."

When Bank and her colleagues reacted samples in the lab with surrogate drilling fluids, they found that the uranium was indeed, being solubilized.

In addition, she says, when the millions of gallons of water used in come back to the surface, it could contain uranium contaminants, potentially polluting streams and other ecosystems and generating hazardous waste.

The research required the use of very sophisticated methods of analysis, including one called Time-of-Flight Secondary Ion Mass Spectrometry, or ToF-SIMS, in the laboratory of Joseph A. Gardella Jr., Larkin Professor of Chemistry at UB.

The UB research is the first to map samples using this technique, which identified the precise location of the uranium.

"Even though at these levels, uranium is not a radioactive risk, it is still a toxic, deadly metal," Bank concludes. "We need a fundamental understanding of how uranium exists in shale. The more we understand about how it exists, the more we can better predict how it will react to 'fracking.'"

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Citation: 'Hydraulic fracturing' mobilizes uranium in marcellus shale (2010, October 25) retrieved 19 September 2019 from https://phys.org/news/2010-10-hydraulic-fracturing-mobilizes-uranium-marcellus.html
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Oct 25, 2010
if the uranium leeching is really significant than maybe it could be mined in the process of cleaning up and thus pay for the cleaning, i wonder to what extend fracking with supercritical co2 instead of water presents the same nuisance/oppertunity

Oct 25, 2010
Again with those pesky "Unintended Consequences", yet the petropeople continue to insist that this hydraulic fracturing process poses no threat to human or environmental well-being.

Much the same yield of natural gas could be achieved by simply sinking multiple wells over a larger area and collecting the output centrally.
But since this would, of necessity, cost more in development and more to maintain over the lifetime of the site, it is not to be thought of, since it translate into into a marginal reduction in profitability, which, as we all know, is the raison d'etre of any and all human endeavor.

The reduction in profitability, of course, depends upon how the cost accounting is performed. If the "external costs" of a project like this are factored in, then it becomes clear which process is actually the most profitable.

But why should the petropeople concern themselves with the "external costs" when they can shift them off on the Public, while pocketing the proceeds?

Oct 25, 2010
if the uranium leeching is really significant than maybe it could be mined in the process of cleaning up and thus pay for the cleaning, i wonder to what extend fracking with supercritical co2 instead of water presents the same nuisance/oppertunity


Probably not even close to economical to extract this Uranium, but still sufficient contamination to create a significant health risk.

A popular misconception is that this is simply H2O being pumped at pressure. The unfortunate fact is that this hydraulic fluid is a toxic mixture of many different chemicals, none of which are inert or free of health risk upon exposure.

Like all petro exploitation, it's dirty business, and the costs and risks of development need to be honestly and straightforwardly accounted for, since not all of the consequences of development(as all too clearly illustrated here) can be "contained" or mitigated.

Oct 25, 2010
So now to fracking's legacy of exploding tap water...


and hair-coloring well water...


...we are to add toxic heavy metals in groundwater and possibly streams and lakes.

The story just gets better and better over time.

Regarding the Uranium mining idea: might be possible if all the backwash came up in one spot. Unfortunately, the very nature of fracking makes the places where the toxic sludge comes back up, utterly unpredictable (and potentially affecting a wide area.)

Oct 26, 2010
Uranium exists naturally in many water supplies. You'll also find Magnesium, Arsenic, Radon, and many other such "scary" contaminants. Modern water treatment can remove most of these. Even contaminants such as Benzene can be removed with aeration.

The key is to know that it exists and to charge the removal of said contaminants back to the industries from where it came.

We need clean water, but we also need energy. Let's recognize that we are working with a balancing act and attempt to assess costs where they belong.

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