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.
University at Buffalo (UB) researchers now have found that that hydraulic fracturing
or fracking also causes uranium that is naturally trapped inside Marcellus
shale to be released, raising additional environmental concerns.
research will be presented at the annual meeting of the Geological Society of
America in Denver
on Nov. 2.
shale is a massive rock formation that stretches from New
York through Pennsylvania, Ohio and West
Virginia, and which often is described as the
nation's largest source of natural gas.
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 ground water?"
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 organic
compounds containing natural gas.
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.
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
and her colleagues reacted samples in the lab with surrogate drilling fluids,
they found that the uranium was indeed, being solubilized.
addition, she says, when the millions of gallons of water used in hydraulic
fracturing come back to the surface, it could contain uranium contaminants,
potentially polluting streams and other ecosystems and generating hazardous
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 Gardella Jr., Larkin Professor of Chemistry at UB.
research is the first to map samples using this technique, which identified the
precise location of the uranium.
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."
Research Finds Fracking Mobilizes Uranium in Marcellus Shale
October 26, 2010