by Max Brantley
A study by Duke University and U.S. Geological Survey participants has found no contamination of Arkansas groundwater by gas exploration using hydraulic fracturing.
The scientists sampled 127 shallow drinking water wells in the Fayetteville shale exploration region
Duke scientists had earlier found some contamination in the shale zone in Pennsylvania.
"The hydrogeology of Arkansas's Fayetteville Shale basin is very different from Pennsylvania's Marcellus Shale," [Avner] 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."
Faulty drilling techniques also still hold the potential to cause problems, the scientists 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."