I listened in this week as the Environmental Protection Agency gave an update on its study of the possible impacts of hydraulic fracturing on drinking water. The webinar presentation will be posted on the study homepage.

EPA started the presentation by revealing that natural gas wells account for only 30 percent of “fracked” wells in the United States. The remaining fracked wells are oil wells. Domestic oil production, the EPA continued, has been dependent on hydraulic fracturing for years. Yet the relatively recent use of fracking for natural gas production -- and the problems that production has caused -- are the focus of fierce public debate and the agency's current research.

As the former secretary of Pennsylvania's Department of Conservation and Natural Resources, I was particularly interested in areas where the study featured the state prominently. The EPA is retrospectively studying six cases where fracking is claimed to have contaminated water. Three of those are in Pennsylvania, at Marcellus well sites in Washington, Tioga, and Susquehanna counties. The other three are in North Dakota at a shale oil site, in Texas in the Barnett Shale, and in Colorado at a coalbed methane site.

The study is also examining key phases of the fracking process -- water acquisition, the mixing of chemicals, the injection of those fluids, the handling of flowback and produced water at the well site surface, and the treatment and disposal of drilling wastewater  -- and evaluating what the potential is at each step for drinking water contamination.

The EPA is acquiring its information from nine drilling companies selected at random. According to EPA, the companies have drilled a total of 25,000 wells in 590 counties across the country. The agency is analyzing 394 of those gas wells, drilled between 2009 and 2010, and compiling the data into computer models. Last year, the EPA conducted water sampling at the study locations from July to November, and additional sampling will take place sometime between March and July.

Pennsylvania’s Monongahela and Susquehanna rivers will get a closer look, too. With data supplied by the Pennsylvania Department of Environmental Protection and EPA Region 3, the study is modeling the potential harm to drinking water from the discharge of drilling wastewater by treatment plants into streams. The research will also examine the possibility for frackwater to migrate upward from shale beds and contaminate drinking water.

So what isn’t the EPA studying? Concerns not being directly examined include whether fracking or wastewater disposal causes earthquakes, whether flowback water should be used to de-ice roads, and the health consequences that fracking may have on people or animals. Toxicity data gathered in the current study, however, could be used for health research in the future.

Throughout the presentation, the EPA extensively discussed its commitment to transparency. The study plan was posted for public comment, and there is extensive information available about the chemical and analytic methods being applied in the study. The first report of the study's results will be sent to the EPA Science Advisory Board in December for peer review and for public comments. The next EPA update is expected in May or June.

Image: D. Sharon Pruitt