All CATEGORIES
☰ Menu
Ohio Utica Shale

Study finds no water contamination from drilling in Arkansas

By Bob Downing Published: May 15, 2013

From Duke University:

DURHAM, N.C. -- A new study by scientists at Duke University and the U.S. Geological Survey (USGS) finds no evidence of groundwater contamination from shale gas production in Arkansas.

"Our results show no discernible impairment of groundwater quality in areas associated with natural gas drilling and hydraulic fracturing in this region," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

The scientists sampled 127 shallow drinking water wells in areas overlying Fayetteville Shale gas production in north-central Arkansas. They analyzed the samples for major and trace elements and hydrocarbons, and used isotopic tracers to identify the sources of possible contaminants. The researchers compared the chemical composition of the contaminants to those found in water and gas samples from nearby shale gas drilling sites.

"Only a fraction of the groundwater samples we collected contained dissolved methane, mostly in low concentrations, and the isotopic fingerprint of the carbon in the methane in our samples was different from the carbon in deep shale gas in all but two cases," Vengosh said. This indicates that the methane was produced primarily by biological activity in the region's shallow aquifers and not from shale gas contamination, he said.

"These findings demonstrate that shale gas development, at least in this area, has been done without negatively impacting drinking water resources," said Nathaniel R. Warner, a PhD student at Duke and lead author of the study.

Robert Jackson, a professor of environmental sciences at Duke, added, "Overall, homeowners typically had good water quality, regardless of whether they were near shale gas development."

Vengosh, Warner, Jackson and their colleagues published their peer-reviewed findings in the online edition of the journal Applied Geochemistry.

Hydraulic fracturing, also called hydrofracking or fracking, involves pumping water, sand and chemicals deep underground into horizontal gas wells at high pressure to crack open hydrocarbon-rich shale and extract natural gas. Accelerated shale gas drilling and hydrofracking in recent years has fueled concerns about water contamination by methane, fracking fluids and wastewater from the operations.

Previous peer-reviewed studies by Duke scientists found direct evidence of methane contamination in drinking water wells near shale-gas drilling sites in the Marcellus Shale basin of northeastern Pennsylvania, as well as possible connectivity between deep brines and shallow aquifers, but no evidence of contamination from fracking fluids.

"The hydrogeology of Arkansas's Fayetteville Shale basin is very different from Pennsylvania's Marcellus Shale," Vengosh noted. Far from contradicting the earlier studies, the Arkansas study "suggests that variations in local and regional geology play major roles in determining the possible risk of groundwater impacts from shale gas development. As such, they must be taken into consideration before drilling begins."

Human factors -- such as the drilling techniques used and the integrity of the wellbores – also likely play a role in preventing, or allowing, gas leakage from drilling sites to shallow aquifers, Vengosh said.

"The take-home message is that regardless of the location, systematic monitoring of geochemical and isotopic tracers is necessary for assessing possible groundwater contamination," he said. "Our findings in Arkansas are important, but we are still only beginning to evaluate and understand the environmental risks of shale gas development. Much more research is needed."

Vengosh, Warner and Jackson's coauthors on the new study were Timothy M. Kresse and Phillip D. Hays of the USGS, and Adrian Down and Jonathan D. Karr of Duke.

Funding for the study was provided by Duke's Nicholas School of the Environment and the Duke Center on Global Change. Field sampling activities were funded by Shirley Community Development Corporation; Faulkner County, Ark.; the University of Arkansas; the Arkansas Water Resource Center; and the USGS Arkansas Water Science Center.

###

Print
Add This

SUBSCRIBE VIA RSS

OHIO.COM VIDEOS

See the most recent drilling report and an injection wells map From NewsOutlet.org
Prev Next

Utica and Marcellus shale web sites

Ohio Department of Natural Resources' Division of Oil and Gas Resources Management State agency Web site.

ODNR Division of Oil and Gas Resources Management. State drilling permits. List is updated weekly.

ODNR Division of Geological Survey.

Ohio Environmental Protection Agency.

Ohio State University Extension.

Ohio Farm Bureau.

Ohio Oil and Gas Association, a Granville-based group that represents 1,500 Ohio energy-related companies.

Ohio Oil & Gas Energy Education Program.

Energy In Depth, a trade group.

Marcellus and Utica Shale Resource Center by Ohio law firm Bricker & Eckler.

Utica Shale, a compilation of Utica shale activities.

Landman Report Card, a site that looks at companies involved in gas and oil leases.FracFocus, a compilation of chemicals used in fracking individual wells as reported voluntarily by some drillers.

Chesapeake Energy Corp,the Oklahoma-based firm is the No. 1 driller in Ohio.

Rig Count Interactive Map by Baker Hughes, an energy services company.

Shale Sheet Fracking, a Youngstown Vindicator blog.

National Geographic's The Great Shale Rush.

The Ohio Environmental Council, a statewide eco-group based in Columbus.

Buckeye Forest Council.

Earthjustice, a national eco-group.

Stop Fracking Ohio.

People's Oil and Gas Collaborative-Ohio, a grass-roots group in Northeast Ohio.

Concerned Citizens of Medina County, a grass-roots group.

No Frack Ohio, a Columbus-based grass-roots group.

Fracking: Gas Drilling's Environmental Threat by ProPublica, an online journalism site.

Penn State Marcellus Center.

Pipeline, blog from Pittsburgh Post-Gazette on Marcellus shale drilling.

Allegheny Front, environmental public radio for Western Pennsylvania.