David Biello over at Scientific American had a story in 2011 that looked at research establishing a link between methane contamination in well water and nearby hydraulic fracturing of shale rock. The research came out of Duke University and was published online in Proceedings of the National Academy of Sciences. The Duke researchers analyzed water samples from 60 wells located within a kilometre of active  shale-gas drilling operations — specifically, the Marcellus and Utica shale formations of northeastern Pennsylvania and upstate New York. They found that “average and maximum methane concentrations in drinking-water wells increased with proximity to the nearest gas well” and were at levels high enough to pose “a potential explosion hazard.”

As Biello pointed out, this “marks the first time that drinking water contamination has been definitely linked to fracking.” His story, which is old but I’ve just come across, is well worth the read. He makes clear that while a small amount of methane isn’t uncommon in most aquifers in the region, the researchers were able to distinguish between “new” methane being produced by the ongoing decay of biological material and “old” methane trapped and released from fossil rock. This was done by measuring the ratio of radioactive carbon present in the methane. Very cool.

The Worldwatch Institute just issued this statement:

Washington, DC – New analysis on the amount of methane, a potent greenhouse gas, released from natural gas production and transport reinforces Worldwatch’s long-stated positions that the natural gas industry must be more open to effective regulation and must more effectively minimize the risk of water contamination, local environmental degradation, and air pollution, including methane leakage, associated with industry activities. The analysis does not, however, change our essential calculus that natural gas can facilitate the transition to a low-carbon economy, and continues to enjoy significant advantages over coal as an energy source.
 
For more than a year, the Worldwatch Institute has maintained a rigorous and ongoing program – our Natural Gas and Sustainable Energy Initiative – that explores the role of natural gas in a low-carbon economy. With media attention focused on the amount of methane leakage connected to energy produced from natural gas, we wish to reiterate some key findings from our research:
 
Natural gas enjoys a broad set of advantages over coal in terms of its ability to partner with renewables in the transition to a low-carbon future, from its dramatically improved ability to scale up and down to meet the needs of an efficient, variable and flexible electric grid, to lower carbon footprint at the point of production.

While Worldwatch has identified greenhouse gas (GHG) emissions in the form of methane leakage, especially during natural gas production, as a serious concern, our analysis indicates that the problem can largely be mitigated through a combination of more effective regulation and better practices from the natural gas industry itself, both of which are essential if natural gas is to earn broad support as an alternative to aging coal plants.

There remains a need for better data on the amount of greenhouse gases emitted during the life cycles of both natural gas and coal. The Worldwatch Institute is currently working on a joint study to develop a rigorous and transparent life-cycle assessment of electricity generated from both natural gas and coal, using what we believe to be the best currently available data.

Recent data from the EPA suggest that it is appropriate to revise previous estimates of methane emissions upwards. Nevertheless, our preliminary analysis suggests that the best new estimates of greenhouse gases emitted during the full life-cycle of natural gas and coal do not undercut the environmental advantages of natural gas over coal. We are reserving final judgment until the conclusion of our own study.