Duke scientists sampled 127 drinking water wells over the Fayetteville Shale gas development area of Arkansas, where 4,000 wells have been drilled. The samples were analyzed for radioisotopes and chemicals and those results were compared to analysis of flowback water from gas wells. The scientists found no evidence that natural gas development using fracking contaminated shallow drinking water wells.
This is the same group at Duke's Nicholas School of the Environment that 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.
According to Avner Vengosh, a professor of geochemistry who participated in the study, "the take-home message is that regardless of the location, systematic monitoring of geochemical and isotopic tracers is necessary for assessing possible groundwater contamination."
Pennsylvania does not require this sort of systematic, geochemical and isotopic monitoring.
