The current issue of Scientific American contains a feature article assessing the issue of water contamination in gas fracking operations, a subject also treated in Spectrum last year. Notably, the SciAm article reports academic research in which water contamination by stray methane but not fracking fluid was found near gas wells. An editorial, building on the article, calls for a slowdown in hydraulic fracturing.
The article by Chris Mooney, "The Truth about Fracking," identifies three ways in which water could in theory be contaminated: leaks or overflows from ponds containing flow-back fluid from fracking operations; cracks propagating from wells deep underground that connect with existing fissures or old wells; and cracks in the cement casing of gas wells, closer to the surface. Mooney reports that a Duke University scientist and colleagues found methane in 51 of 60 drinking water wells nearly mining operations in the Marcellus Shale, but no evidence of fracking fluids.
That strongly suggests to the lead scientist, Robert B. Jackson of Duke's Nicholas School of the Environment, that leaks from well casings are likely to blame--the least ominous and easiest to address of the three possible pathways. But propagating fissures are not completely excluded.
The editorial, "Safety First, Fracking Second," calls for more research into these issues and revised regulation. It suggests, among other things, required inspection of well casings, storage of flow-back fluid in sealed tanks rather than open ponds, and injection of tracer fluids into wells along with fracking fluid so that any leakage can be more easily and definitively identified. Lacking such precautions, the magazine argues, public support for fracking--a technology with big obvious benefits--could be jeopardized.