Natural gas: boom, disaster or both?

MILLBROOK — A recent Google search for the term “Marcellus shale” provided, as the top two results, an Earth Justice site describing the evils of hydraulic fracturing (fracking) for natural gas; then, as if to confirm the first site’s worst fears, Minuteman Spill Response, Mifflinville, Pa.Compared to other forms of mining, fracking is “poorly regulated,” said Professor Rob Jackson of Duke University, and added that its environmental impact is even less well understood. As lead researcher of the first major peer-reviewed study of fracking on water wells, Jackson spoke at the Cary Institute of Ecosystem Studies on Thursday, June 9, and presented his team’s results (which had been published Tuesday, May 17) in the Proceedings of the National Academy of Sciences.The health risk posed by fracking for natural gas appears to be twofold: first, leakage of natural gas into well water and the environment. Its human toxicity is not known, but colorless, odorless methane (natural gas is almost all methane) does cause death by asphyxiation and is, highly explosive.Second, spillage of the fracking fluid itself — mostly water but also a small percentage of up to 50 chemicals (see sidebar) — or of the ancient and possibly radioactive underground brine. As pressure is eased in a fracked section, the effluvia backflushes to the surface. With it comes highly saline water millions of years old that contains naturally occurring radioactive isotopes. (Residents of areas where Devonian beds lie close to the surface know about this from radon in their basements.) Jackson’s team studied both possibilities, omitting only airborne natural gas for lack of the proper instruments (since corrected). They sampled 68 private groundwater wells from 120 to 625 feet deep in northeastern Pennsylvania and adjacent New York, an area of active and future drilling. About half were within one kilometer of one or more fracking sites, an early hypothesis of the critical radius. The team’s analysis “found no evidence for contamination of the shallow wells near active drilling sites from deep brines and/or fracturing fluids.”That’s the good news. This finding has nothing to do with major spills, a number of which have occurred. One last April, near Canton, Pa., sent thousands of gallons of effluent across fields and into a stream, polluted several local wells and may have been a blow out. Chesapeake Energy, its owner, has temporarily suspended its drilling throughout the state as a result.Natural-gas contamination of well water was a different story. All but eight of the 68 wells qualified for this testing and 26 were in active drilling zones. The samples from 51 of 60 wells (85 percent) contained methane but the amount was 17 times higher in well water near a fracking hole. The average methane concentration in these wells “fell within the defined action level for hazard mitigation recommended by the U.S. Office of the Interior.” Nine were above the action level, the top one was more than six times higher than the low threshold. Strong evidence that the methane detected came from drilling, not nature, was that three different tests found it to be thermogenic — created by geologic pressure and heat — rather than biogenic, from decomposing organic matter. In other words, the methane came from deep underground, not near the surface. (The amount of biogenic methane found in these wells was “negligible,” detected only because the instruments were so sensitive.)The study posits several sources for this thermogenic methane, the most likely being leaking well casings. As the gas is under pressure, it would find any open path to the surface, a drilled water well being especially convenient. The gas could also be forced up and out by fracking pressure, which is typically 10,000 pounds per square inch, or enough to turn concrete to powder twice over. Either would take advantage of two phenomena in the Marcellus, one natural and one anthropogenic (caused by human beings): the area is and has long been tectonically active, with open faults and cracks. It’s also riddled with oil and gas wells — active, dry and abandoned. The reserves of natural gas trapped in vast shale deposits may last for many decades, providing the U.S. with a soft, high-energy transition away from oil and coal to the distant future when almost all energy we consume will be renewable. But at what cost to the region’s environment and the health of local residents?Following release of this study, Pennsylvania enlarged the permissible distance between a private water well and a natural-gas well from 1,000 to 2,500 meters. Texas now requires that fracking operations divulge the contents of their fracking fluid. The federal Environmental Protection Agency (EPA), mandated by Congress, is conducting its own drinking-water studies, both near fracking sites and in advance of fracking, to establish a control (a somewhat disingenuous criticism of the Duke study, given the variety of test distances from fracking activity and the large number of tests). The EPA plans to complete its study in 2012. Jackson and team plan another study, this time possibly in North Carolina. Meanwhile, New York’s EPA has just released a 900-page study that says the state can safely allow extracting natural gas with the new, two-part procedure as long as it is outside the New York City watershed and those of other large communities. A 60-day comment period before Governor Andrew Cuomo withdraws the drilling moratorium starts Aug. 1. Given that scientists are only now beginning to understand the complex fluid dynamics of fracking, the recommendation at the end Jackson’s paper is worth pondering: “Greater stewardship, knowledge, and — possibly — regulation are needed to ensure the sustainable future of shale-gas extraction.”Of great concern in arid regions is that each fracking operation swallows 3 to 5 million gallons of fresh water, or a 1-acre pond 10 to 15 feet deep. Of concern everywhere: Some of this effluent returns to the surface and must be either stored or treated to remove salt and metal isotopes. One must also consider that methane is a potent greenhouse gas itself and it depletes the earth’s ozone layer. Its presence in the air, largely a product of the industrial revolution, has increased substantially over the past decade.Of the major benefits of a gas-fueled rural economic boom, the windfalls for governments and property owners are undeniable. But the thousands of new jobs often cited is a mirage: drillers don’t employ many locals, they relocate experienced fracking crews from the oil patch. These roustabouts do spend some of their paychecks locally, but as one said in a New Yorker article about the fracking fields of North Dakota, “In your 12 hours off, after you do your clothes and eat supper, all you do is sleep.” Supermarkets might record more receipts. And taverns anchored above the Marcellus shale. Tom Parrett is a magazine writer and editor specializing in science and technology, and serves as creative director of The Magazine Works. He lives in Millerton and Greenwich Village.