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By Alan Kovski
June 4 — Hydraulic fracturing and associated oil and natural gas drilling activities can threaten the quality or quantity of drinking water resources, but the instances of contamination have been relatively few, the Environmental Protection Agency said June 4 in the release of a long-awaited study.
“We did not find evidence that these mechanisms have led to widespread, systemic impacts on drinking water resources in the United States,” the EPA said in its draft assessment of risks to drinking water.
“Of the potential mechanisms identified in this report, we found specific instances where one or more mechanisms led to impacts on drinking water resources, including contamination of drinking water wells. The number of identified cases, however, was small compared to the number of hydraulically fractured wells,” the report said.
The report used an expanded definition of drinking water resources, including in the category for undrinkable saline waters on the theory that those waters might someday be desalinated and used for drinking.
The importance of the 998-page report is that it can serve as a critical resource for federal, state, local and tribal authorities and for industry to better protect drinking water, said Thomas Burke, deputy assistant administrator of the EPA Office of Research and Development, during a telephone news conference.
Several industry and environmental advocacy groups saw the draft assessment as a vindication of what they have been saying for years, despite their opposing views.
Burke was more cautious. The study is a compilation of data drawn from case studies and more than 950 other studies that can be used by policymakers and regulators as reference material for their work, Burke said.
“The study is not a human health risk assessment,” Burke said. Nor is it a policy document, nor does it identify policy options, he said. Nor was the study developed to quantify instances of contamination, he said.
The study itself said, “Although no attempt has been made in this assessment to identify or evaluate comprehensive best practices for states, tribes, or the industry, we describe ways to avoid or reduce the impacts of hydraulic fracturing activities as they have been reported in the scientific literature.”
The report, requested by Congress and planned by EPA in 2011, was released for public comment and peer review. The EPA Science Advisory Board will conduct the peer review and has scheduled three public teleconferences and a two-day meeting during Sept. 30-Oct. 30. Results of the peer review are not expected before 2016.
The draft assessment found that hydraulic fracturing poses the risk of contamination to drinking water from spills at the well site, mishandling of wastewater, underground leaks from flaws in well casing or well cementing, and drilling directly into drinking water resources—risks that have been recognized for decades.
“In the draft report, the agency appears to take a very broad definition and scope of fracturing and categorizes some processes that are not part of actual fracturing activity, such as casing and cementing of wells,” said Barry Russell, president of the Independent Petroleum Association of America, in a statement released after the report appeared.
The study repeatedly referenced “fracturing-related” activities connected to contamination incidents, leaving unclear the question of whether it was fracturing itself or something like poor well casing that led to a spill. Those factors can be interrelated, Burke indicated.
“There are instances where fracking itself led to problems with well construction that led to contamination,” Burke said.
The study cited examples drawn from 2006-2012 state and industry data.
“Casing at a production well near Killdeer, N.D., ruptured following a pressure spike during hydraulic fracturing, allowing fluids to escape to the surface,” the report said. “Brine and tert-butyl alcohol were detected in two nearby water wells. Following an analysis of potential sources, the only potential source consistent with the conditions observed in the two impacted wells was the well that ruptured.”
The study complicated the issue through its definition of drinking water resources. That had bearing especially on the report's treatment of drilling into some saline aquifers as drilling directly into drinking water resources.
The report did not make clear whether drilling and fracturing were ever conducted in freshwater resources.
Similarly, the report's examples of contamination through leaks typically referred to drinking water resources without specifying whether the leaks were into freshwater aquifers or untapped saline aquifers.
The definition for drinking water resources used by the EPA study was any water with total dissolved solids below 10,000 milligrams per liter. That is a common dividing point between moderately and highly saline water, and it is used, for example, by the U.S. Geological Survey.
U.S. drinking water systems typically restrict drinking water to less than 500 m/L total dissolved solids.
“This study provides solid scientific analysis that fracking has contaminated drinking water around the country,” said Amy Mall, a senior policy analyst for the Natural Resources Defence Council, an activist group, in a statement released June 4.
“This study is missing some critical elements, hamstringing its comprehensiveness. Among other things, there are reports industry has not cooperated in providing important information,” Mall said.
The study cited some limitations on information available, such as claims of confidentiality for some chemicals used, sealed documents in litigation, or the scarcity of baseline water sampling prior to oil or gas drilling.
“There is a lack of baseline surface water and ground water quality data. This lack of data limits our ability to assess the relative change to water quality from a spill or attribute the presence of a contaminant to a specific source,” the study said.
But for the work on the five-year study, oil and gas companies were helpful, Burke said, remarking, “We had a generally very cooperative relationship with industry.”
Industry groups and some Republicans in Congress welcomed the study as a verification of the safety of hydraulic fracturing as practiced by U.S. companies and regulated by states.
“After more than five years and millions of dollars, the evidence gathered by EPA confirms what the agency has already acknowledged and what the oil and gas industry has known,” said Upstream Group Director Erik Milito of the American Petroleum Institute, an industry group. “Hydraulic fracturing is being done safely under the strong environmental stewardship of state regulators and industry best practices.”
Similar statements were released by Sens. Lisa Murkowski (R-Alaska) and Jim Inhofe (R-Okla.), the chairmen, respectively, of the Senate Energy and Natural Resources Committee and the Environment and Public Works Committee.
Statements from Inhofe and Rep. Rob Bishop (R-Utah), chairman of the House Natural Resources Committee, suggested the Obama administration has been looking for excuses to increase regulation of hydraulic fracturing, as it did with its final rule in March to update regulations for oil and gas drilling on federal lands.
Three members of Congress focused in part on the study's notes about data limitations. “Congress must be looking closely at ways to close these data gaps moving forward in order to prevent any further contamination,” said a statement from Reps. Frank Pallone (D-N.J.), Diana DeGette (D-Colo.) and Paul Tonko (D-N.Y.).
Sen. Ed Markey (D-Mass.) said, “This draft report verifies what we have known for years, that hydraulic fracturing and related activities have the potential to severely impact drinking water and endanger public health and the environment. While the number of cases studied may be small, the impacts to public health and safety are large.”
Markey may have been making a general reference to case studies that have appeared elsewhere when he mentioned public health and safety.
The EPA draft assessment said it “did not contain a human health risk assessment” and it “does not identify populations that are exposed to chemicals, estimate the extent of exposure, or estimate the incidence of human health impacts.”
To contact the reporter on this story: Alan Kovski in Washington at firstname.lastname@example.org
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