Drilling and Fracking and the Environment
by Bill Chameides | May 17th, 2013
posted by Erica Rowell (Editor)
A rig in Arkansas where the technique of fracking is used in the drilling operations. Duke and USGS researchers found no evidence of groundwater contamination from shale gas production in Arkansas. (Timothy Kresse, USGS)
Water contamination depends on the local geology.
Initial Fracking Study Found Contamination
Back in May 2011 my Duke colleagues Avner Vengosh and Rob Jackson and other co-authors published a paper in the Proceedings of the National Academy of Sciences that caused a fracking firestorm or at least a media fracking-firestorm.
The authors found evidence for methane contamination in residential drinking water wells in Pennsylvania and New York overlying the Marcellus shale formation. The contamination correlated strongly with proximity to drilling sites that used the controversial technique of horizontal drilling and hyrdrofracturing (or fracking), and isotopic data linked the contamination to shale gas — a link possibly due to direct communication of the gas from the deep shale but more likely due to faulty well casings that allowed gas to leak from the well into nearby local aquifers.
(The possibility that faulty well casings and/or drilling practices may be a determining factor in causing drinking water contamination would appear to question the wisdom of the administration’s newly released rules for drilling on public lands, which only require testing a single well in an area.)
Study Questioned by Industry et al. but Confirmed by Other Studies
The May 2011 paper was met with derision and worse from the gas industry.
Despite the fact that the Duke paper reported no evidence of any water contamination from the fracking fluids — a major issue for those who oppose fracking and a finding that the frackers would presumably champion — the industry panned the work as “poor science” and accused the authors of having a political, anti-fossil fuel agenda that colored and biased their results.
To wit: “Once again, what you have here is a paper that draws pretty firm conclusions without much data at all to back any of them up,” Energy In Depth, a coalition of energy producers, said in a statement. The industry group America’s Natural Gas Alliance criticized the study for lacking “key data that would be needed to validate its conclusions.” (Read more here, here and here.)
Well, despite the barbs from the industry, the Duke team has continued their work, collecting samples around the country where fracking is occurring. And, lo and behold, what do you know, additional data from the Marcellus has largely confirmed the earlier findings reported in the 2011 paper. (See here and here.)
New Study Finds No Contamination in Formation Studied
This week that same Duke team, in collaboration with scientists from the U.S. Geological Survey, published a paper in the Journal of Applied Geochemistry on results of a study similar in design to that used for the 2011 study for the Marcellus shale but in this case looking at drinking water wells in Arkansas near fracking sites overlying the Fayetteville shale formation. The lead author of this new paper was Nathaniel Warner.
On the basis of 127 samples, the authors concluded that there was “no discernible impairment of groundwater quality in areas associated with natural gas drilling and hydraulic fracturing in this region.” Lead author Warner says that “[t]hese findings demonstrate that shale gas development, at least in this area, has been done without negatively impacting drinking water resources.”
Water Contamination Depends on Local Geology
Does this mean that the authors are retracting their results from the Marcellus shale? Of course not. Here’s how Avner Vengosh explains the contrasting results:
“The hydrogeology of Arkansas’s Fayetteville Shale basin is very different from Pennsylvania’s Marcellus Shale … 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.”
So this latest paper leads me to wonder: what is the agenda of these guys anyway? Clearly not anti-fossil fuels given the Arkansas results, and no way pro-fossil fuels given the Pennsylvania result. Could it be that their agenda is scientific, and they report what they find regardless of who’s agenda is helped or hindered?filed under: energy, fracking, natural gas