Scientists from the University of Buffalo studying hydraulic fracturing, or fracking, say the gas drilling technique could force uranium in the Marcellus shale to move into groundwater. The Marcellus shale, a massive rock formation that stretches from New York through Pennsylvania, Ohio and West Virginia, is often described as the nation’s largest source of natural gas.
To get to the natural gas trapped in the Marcellus shale, drillers use fracking, which involves injecting water, sand, and a cocktail of chemicals at high pressure into rock formations thousands of feet below the surface. Environmentalists have been concerned that fracking could contaminate the waterways in the Marcellus shale, some of which supply water to cities along the East Coast.
The University of Buffalo researchers 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.
“We found that the uranium and the hydrocarbons are in the same physical space,” lead researcher Tracy Bank, PhD, said in a statement. “We found that they are not just physically — but also chemically — bound.â€
The researchers theorized that the process of drilling to extract the natural gas could start mobilizing metals, forcing them into the soluble phase and causing them to move around. When they reacted samples in the lab with surrogate drilling fluids, they found that the uranium was indeed, being solubilized.
According to the scientists, 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 waste.
“Even though at these levels, uranium is not a radioactive risk, it is still a toxic, deadly metal,” Banks said. “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.'”
The researchers will present their findings at the annual meeting of the Geological Society of America in Denver on Nov. 2.