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
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