An article to appear in the Proceedings of the National Academy of Sciences, “Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing,” reports finding methane in Pennsylvania and New York groundwater that can be attributed to nearby natural gas resource production. In brief, the study finds that substantially higher dissolved methane levels in water from wells within 1 kilometer of an active gas production site than in nearby wells that are farther than 1 kilometer from active gas wells. Further investigation demonstrates that most of the methane is almost certainty from deep geologic sources (as, for example, the shale gas produced via fracking) and not biogenic methane from nearer the surface.
That deep rumbling sound in the distance is the slow shifting of the burden of proof moving from groundwater interests a few steps closer to shale gas producers. One published study doesn’t end investigation, of course. This particular study focused in and around Dimock, Pennsylvania, an area of significant controversy with respect to groundwater and shale gas development. Other areas of the Marcellus Shale in Pennsylvania as well as the extensively fracked Barnett Shale in Texas and Haynesville Shale in Louisiana should also be studied. The problem may be general with respect to fracking or specific with respect to the geology of the area, methods used locally, or operating practices of specific companies in the area examined.
In addition, evidence collected before and after well development would be useful. The report indicated that several sites currently greater than 1 kilometer from an active well are scheduled for future drilling, so a follow-up study using the same methods and sites should provide additional insights.
Also significant in the report is that it found no evidence of fracking fluids in groundwater, nor any evidence of migration of deep brines into groundwater near active gas wells.
A separate paper by the study authors and others makes research and policy recommendations. Their research recommendations are:
- Initiate medical review of the health effects of methane.
- Construct a national database of methane, ethane, and propane concentrations and other chemical attributes in drinking water.
- Evaluate the mechanisms of methane contamination in drinking water.
- Refine estimates for greenhouse‐gas emissions of methane associated with shale‐gas extraction.
- Systematically sample drinking water wells and deep formation water.
- Study disposal of waste waters from hydraulic fracturing and shale-gas extraction.