A 121 page draft report, Investigation of Ground Water Contamination near Pavillion, Wyoming, links fracking to that contamination. Both of the following two quotes are from the extended abstract. The EPA was called in due to complaints in the area.
In response to complaints by domestic well owners regarding objectionable taste and odor problems in well water, the U.S. Environmental Protection Agency initiated a ground water investigation near the town of Pavillion, Wyoming under authority of the Comprehensive Environmental Response, Compensation, and Liability Act. The Wind River Formation is the principal source of domestic, municipal, and stock (ranch, agricultural) water in the area of Pavillion and meets the Agency's definition of an Underground Source of Drinking Water. Domestic wells in the area of investigation overlie the Pavillion gas field which consists of 169 production wells which extract gas from the lower Wind River Formation and underlying Fort Union Formation. Hydraulic fracturing in gas production wells occurred as shallow as 372 meters below ground surface with associated surface casing as shallow as 110 meters below ground surface. Domestic and stock wells in the area are screened as deep as 244 meters below ground surface. With the exception of two production wells, surface casing of gas production wells do not extend below the maximum depth of domestic wells in the area of investigation. At least 33 surface pits previously used for the storage/disposal of drilling wastes and produced and flowback waters are present in the area. The objective of the Agency's investigation was to determine the presence, not extent, of ground water contamination in the formation and if possible to differentiate shallow source terms (pits, septic systems, agricultural and domestic practices) from deeper source terms (gas production wells).Much of the next paragraphs detail the specific chemicals and wells in which those chemicals were found. The likely source was fracking. An EPA report must consider all possibilities.
Alternative explanations were carefully considered to explain individual sets of data. However, when considered together with other lines of evidence, the data indicates likely impact to ground water that can be explained by hydraulic fracturing. A review of well completion reports and cement bond/variable density logs in the area around MW01 and MW02 indicates instances of sporadic bonding outside production casing directly above intervals of hydraulic fracturing. Also, there is little lateral and vertical continuity of hydraulically fractured tight sandstones and no lithologic barrier (laterally continuous shale units) to stop upward vertical migration of aqueous constituents of hydraulic fracturing in the event of excursion from fractures. In the event of excursion from sandstone units, vertical migration of fluids could also occur via nearby wellbores. For instance, at one production well, the cement bond/variable density log indicates no cement until 671 m below ground surface. Hydraulic fracturing occurred above this depth at nearby production wells.The extended abstract continues with exploration of gas well and comes to the same conclusion. Fracking is causing contamination of local water and local gas wells. This is not a safe endeavor. It needs to stop until we know how to proceed without harm to the environment and harm to people's drinking water.
The National Memo ran an article by Pro Publica reporters that included an interview with a spokesman for the company that is doing the fracking.
A spokesman for EnCana, the gas company that owns the Pavillion wells, did not immediately respond to a request for comment. In an email exchange after the EPA released preliminary water test data two weeks ago , the spokesman, Doug Hock, denied that the company's actions were to blame for the pollution and suggested it was naturally caused.
"Nothing EPA presented suggests anything has changed since August of last year -- the science remains inconclusive in terms of data, impact, and source," Hock wrote. "It is also important to recognize the importance of hydrology and geology with regard to the sampling results in the Pavillion Field. The field consists of gas-bearing zones in the near subsurface, poor general water quality parameters and discontinuous water-bearing zones."Since the EPA report is a draft version, to be finalized Spring 2012, it is by definition inconclusive at this time. The data, however, indicates that Mr. Hock is wrong.
13 November 2011, Original Pedantic Political Ponderings post.
2 January 2012, FollowUp 2.
26 May 2012, FollowUp 3.