EPA Technical Roundtables Concerning Potential Impacts of Hydraulic Fracturing on Drinking Water Resources

In 2010, Congress urged the Environmental Protection Agency (EPA) to study the relationship between hydraulic fracturing and drinking water.

Congress directed the EPA to use the best available, independent sources of information and a transparent and peer-reviewed process, in consultation with others. The study has drawn both support and criticism in how it has been conducted.

Beginning in 2010, the EPA met with stakeholders to identify concerns and study scope and released a final study plan in November 2011. After holding five technical roundtables in November 2012, the EPA released a progress report in December 2012. Each technical roundtable focused on one of the water cycle stages in hydraulic fracturing.

A summary of the roundtable discussions was published in February 2013. Below is a brief description of the discussions in each roundtable. Additional technical workshops are scheduled for Spring 2013 with additional technical roundtables expected in the Summer. 

The EPA expects to release a draft report of results in December 2014 for peer review.

Water Acquisition Roundtable

  • The participants discussed water withdrawal impacts, including the need to differentiate between the impacts of hydraulic fracturing and other impacts. One participant remarked that seasonal impacts to ground water can be greater than hydraulic fracturing impacts.
  • Hydraulic fracturing can have both positive and negative impacts on public water systems (PWS). It was suggested that payment to PWSs for water use in hydraulic fracturing can allow for investment in infrastructure or other long-term needs, and could help small municipalities improve their systems.
  • Water use for hydraulic fracturing constitutes a very small percentage of water use; agricultural and public water supplies use a large percentage of water in the areas where hydraulic fracturing occurs. It was noted that hydraulic fracturing is a “consumptive use” of water. 
  • The panel discussed the use of freshwater in hydraulic fracturing, stating that non-freshwater sources should be developed.
  • The members of the roundtable indicated that air emissions, regulatory structure, use of chemical additives, community impacts, energy use and issues with storing flowback waters for reuse need to be considered.

Chemical Mixing Round Table

  • The EPA is currently examining what chemicals are or have been used in hydraulic fracturing and what might get into drinking water resources. It is gathering available information regarding the chemical, physical and toxicological characteristics of chemicals known to have been used in hydraulic fracturing fluids or found in hydraulic fracturing wastewaters. The EPA is not undertaking a risk assessment.
  • A panel member stated that “drilling through freshwater zones is one of the greatest concerns with hydraulic fracturing and that the effects are from drilling fluids, not hydraulic fracturing fluids. Drilling fluids (which may contain some of the same chemicals used in hydraulic fracturing fluids) are not…part of EPA’s current study.”
  • The EPA’s sources of chemical information include “federal and state government documents, industry-provided data, and other reliable sources based on the availability of clear scientific methodology and verifiable original sources. This includes information provided by nine hydraulic fracturing service companies, nine oil and gas operators, and FracFocus.”
  • The EPA is looking at ground water, wastewater and flowback matrices, all of which vary by chemical.
  • A participant suggested that the EPA consider the fact that chemical use during hydraulic fracturing changes over the life of the play. Another attendee stated that the “chemicals are being used safely and there are no unnecessary risks to the public; companies consider the frequency of use, severity and toxicity when deciding to use a chemical.”
  • The EPA provided information regarding QSAR modeling, which estimates the potential chemical, physical or toxicological properties for a chemical based on the known relationship between chemical structure and toxicity of a large number of chemicals with known properties.
  • A “triple bottom line” analysis considering environmental, social and economic components was suggested.

Well Injection Round Table

  • The panel members discussed the parameters and assumptions in the EPA’s fluid migration model, TOUGH+ (Transport of Unsaturated Groundwater and Heat). This model can evaluate the potential for fluids (liquids and gases) to move from the fracturing zone to drinking water aquifers. This model is a "test of possibility, not probability."
  • As an initial screening point, the use of indicator compounds (such as total dissolved solids or chlorides) was mentioned.
  • The participants emphasized the importance of measuring baseline conditions.
  • There were discussions of the importance of proper cementing and what constitutes a well failure. 

Flowback and Produced Water Round Table

  • Sources of information for the flowback and produced water work include spills database analysis and five retrospective case studies (Bradford County, Pennsylvania; Las Animas/Huerfano Counties, Colorado; Dunn County, North Dakota; Washington County, Pennsylvania; and Wise County, Texas)
  • The EPA is focusing on the number and severity of spills associated with hydraulic fracturing, not the impacts of spills.
  • From the industry’s standpoint, hydraulic fracturing fluid is fluid that is pumped down into the ground; produced water is any water produced from the wellbore; and flowback is water in the initial phase of produced water. The EPA defines flowback and produced water as “wastewater.”
  • For its case study sampling efforts, the EPA chose locations of previous complaints and took samples from streams, drinking water wells, ponds, and other water sources. All samples were taken at one time for a given site.
  • Produced water cannot be categorized in a generic sense because it varies from site to site, region to region.
  • The EPA has established nationally applicable technology-based discharge requirements for most oil and gas discharges under 40 CFR Part 435. Under Part 435, direct dischargers of oil and gas wastewaters are subject to zero discharge requirements which can be met through underground injection of wastewater in disposal wells (40 CFR Part 144, Class II UIC Wells). 

Wastewater Treatment and Waste Disposal Round Table

  • The laboratory and field studies that are relevant to this review include wastewater treatability studies, contaminant residual studies, surface water modeling, source apportionment studies, and disinfection byproduct precursor (DBP) studies.
  • Some panel members discussed the difficulty of determining the source of contaminants in watersheds.
  • The EPA has not yet looked at chemical toxicity issues. The participants suggested that there needs to be a way to characterize toxicity if the wastewater is going to be discharged or reused; the study should address the complexity and toxicity of organics; and a review of toxicity and the effects of surface discharge on aquatic life could provide information on some constituents other than bromide, chloride and sulfate.
  • All positive and negative aspects of reuse need to be discussed. A participant suggested that the EPA consider the effectiveness of treatment prior to reuse and the impacts of residuals generated. It was also recommended that the EPA’s study look at the UIC (Underground Injection Control) program used to dispose of hydraulic fracturing wastewater and the long-term effects of this disposal practice, including pollutant migration issues.
  • There was a discussion of future discharge trends, including when will produced water volumes exceed the potential for reuse, what are the rates of new investment in the oil and gas industry, what new treatment processes are being considered, and what factors will impact future wastewater management (e.g., regulatory drivers, geological constraints, and regional differences). 


This article was prepared by Barclay R. Nicholson (bnicholson@fulbright.com or 713 651 3662)  and Heather Corken (hcorken@fulbright.com or 713 651 8386) from Fulbright's Energy Practice and Environmental Practice, respectively.