Compiled by Stephen Kishewitsch
Perhaps due to the relative newness of the resource, the approach to regulation of the environmental impacts of shale gas extraction may be subject to closer scrutiny in the near future. Although the issues are not particularly new, a number of questions remain to be resolved.
A review by the New York State Department of Environmental Conservation (DEC) released in September 2009, describes quite a few potential effects, some of which are listed here:
• Horizontal drilling and especially hydrofracturing of the shale (fracking), to release the gas, requires large amounts of water, much more than a conventional vertical well (80 times as much, says Sierra Club campaigner Roger Downs). The study quotes estimates that over 800,000 gallons of water are needed per hydraulic fracturing stage, per well, and each well needs several fracturing stages. An entire hydraulic fracturing job may use as much as 5,000,000 gallons of water.
Water withdrawals, from surface water, groundwater and deep aquifers, can result in reduced stream flow, with attendant harm to aquatic life. Pollutants, such as agricultural runoff or municipal effluent, may be insufficiently diluted. Stream ecosystems need the occasional scrubbing that spring snowmelt or heavy rains provide, an effect that can be lost if streamflow is much reduced.
• Contaminated waste water that flows back from the well. Water used in drilling and fracking can contain or dissolve and carry back a long list of compounds – gelling agents, surfactants and chlorides, other dissolved solids, metals, biocides, lubricants, organics and radionuclides. A table in the DEC review lists over 300 compounds either used in additives or found in flowback water or both, some innocuous and some not, like xylenes, benzene and lead. Surface operations can spill diesel and other substances associated with industrial operations.
Flowback water is generally stored in tanks, a lined pit, or in centralized impoundments servicing multiple pads. There are concerns that such containments can leak or fail, releasing tonnes of contaminated water and mud. As Sierra Club campaigner Roger Downs explained in a telephone conversation, there is little or no provision for proper treatment of flowback water after it has spent time in the pit – generally at present it is simply trucked to municipal facilities, that may do no more than dilute and release it themselves.
On the other hand, the New York State review reports that regulatory officials from 15 states have recently testified that groundwater contamination from the hydraulic fracturing procedure, via the borehole or other routes, “is not known to have occurred despite the procedure’s widespread use in many wells over several decades.”
• Noise, vibration and dust from the drilling operation. Landowners who have sold development rights, and their neighbours, have on some occasions reported noise and dust around the clock from nearby operations. Vibration from heavy truck traffic is the basis of some complaints. The township of Dimock in Pennslyvania (see also the next bullet point) has been cited as an example of what can go wrong, with landowners who have sold drilling rights finding their lives disrupted by the effects. Gas flares burn night and day a few hundred feet from peoples’ homes. An online video clip shows one operation, with machinery noise drowning out conversation, across from a homeowner’s front yard.
• Natural gas in drinking water. The New York Times, in a December 8 2009 article, mentions thirteen rural water wells in Dimock, Pennsylvania that were contaminated by natural gas from drilling operations. One of the wells actually blew up. A video clip on Youtube (http://www.youtube.com/watch?v=fLn4zh6Eadw) shows a homeowner setting the flow from her kitchen tap on fire.
• “Hazardous air pollutants (HAP).” Methanol is present as a major component of the additives in the frac water. The DEC review estimates that 3.25 tons of the easily-evaporating methanol will be contained in the flow-back water from each well. “Based on an assumed installation of ten wells per wellsite in a given year, an annual methanol air emission of 32.5 tons (i.e., ‘major’ quantity of HAP) is theoretically possible at a central impoundment.”
The Sierra Club foresees other hazardous gases potentially evaporating from each site as well, namely, other organic compounds (condensates) removed from the natural gas before it is injected into a pipeline. Hydrogen sulphide is also a possible contaminant, although gas from the Marcellus Shale in New York is expected to be very “dry”, i.e., have little or no VOC content, and “sweet”, i.e., have little or no hydrogen sulphide. (“VOC” refers to Volatile Organic Compounds, a common contributor to smog and other forms of air pollution.)
• Ecosystem fragmentation. If drilling operations – and resource extraction relies on many wells – are located in areas of natural wildlife habitat, the many roads that will be driven through the area will fragment and degrade the habitat, and the continuous industrial operation will disrupt wildlife.
On April 23 the NY DEC announced that the watersheds relied on by New York City and Syracuse for drinking water would be excluded from any generic environmental review process related to drilling for shale gas, but activists doubt the effectiveness of that ruling. Calling the DEC study fatally flawed, the Natural Resources Defense Council and 26 other groups have called for a one-year moratorium on drilling in the Marcellus until the proper studies are completed.
Concerns over pollution from shale gas production may parallel some of the reported experience with coalbed methane, which typically involves pumping large volumes of saline water to the surface. The salt then kills vegetation and fish in streams and renders surface water undrinkable. But Kevin Heffernan, Vice President of the Canadian Society for Unconventional Gas, in Calgary, warns against comparing the US and Canadian regulatory environments. “There were some very bad practices in Montana and Wyoming at the beginning of coalbed methane extraction,” he said in a telephone interview. “Those things are not allowed in western Canada,” where the industry has been around in one form or another for a century. In Alberta and BC, all reflow drilling fluids are pumped back deep underground.
Of course, he notes, the regulatory regime in eastern Canada is not as mature.
Please see the following related articles, including a special feature by John Wolnik on the Marcellus Shale deposit, in this issue of IPPSO FACTO:
* How shale gas is redrawing the map for Canadian power generators
* Marcellus gas — a game changer, feature article by John Wolnik
* The Marcellus Shale and gas production (backgrounder)
* Editorial: Will Ontario miss another great gas opportunity?