Overview of US EPA's Study of the Potential ... - ACS Publications

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Chapter 9

Overview of U.S. EPA’s Study of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources J. S. Briskin* and L. Yohannes Office of Science Policy, Office of Research and Development, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue NW, Mail Code 8104R, Washington, DC, 20460, United States *E-mail: [email protected]

In 2010, Congress urged the U.S. EPA to carry out a study on the relationship between hydraulic fracturing and drinking water, using a credible approach that relied on the best available science, as well as independent sources of information. This chapter describes the research that EPA conducted in response to Congress’ request. In addition to an extensive review of the literature, EPA used these research results to inform the Draft Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources. The draft assessment was released for public comment in June 2015 prior to review by EPA’s Science Advisory Board.

Responsible development of domestic oil and gas resources offers important economic and energy security benefits. However, the increase in hydraulic fracturing activities has raised public concerns about the potential for impacts to human health and the environment, including potential impacts to drinking water resources. In response to this concern, and the lack of publicly available scientific data, Congress urged the EPA to study the relationship between hydraulic fracturing and drinking water. In conducting this study, the Environmental Protection Agency (EPA) identified impacts of hydraulic fracturing for oil and gas on drinking water resources and the factors that may affect the severity and frequency of these

© 2015 American Chemical Society In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.


impacts. The study resulted in a draft assessment that integrates a comprehensive review of the existing literature with results from EPA research and with information from stakeholders and the public. EPA’s draft assessment helps to advance the state of science, increase the level of understanding about impacts of hydraulic fracturing on drinking water, and identify areas where data gaps still exist. EPA designed the scope of the study around the hydraulic fracturing water cycle, which describes a set of activities associated with hydraulic fracturing that may interact with drinking water resources (1). The hydraulic fracturing water cycle, shown in Figure 1, consists of the following five stages: (1) acquisition of water needed to create hydraulic fracturing fluids; (2) mixing of water and chemicals on the well pad; (3) injection of fluids into the well to fracture the geologic formation; (4) management of the flowback and produced water on the well pad for treatment or disposal; and (5) reuse, treatment and release of wastewater (flowback, produced water, and other waste generated at the well pad).

Figure 1. Hydraulic Fracturing Water Cycle (2). (Reproduced with permission from reference (2).) The research projects that EPA conducted as part of the study can be categorized under five approaches: analysis of existing data, laboratory studies, computer modeling (scenario evaluations), toxicity studies, and case studies.

Analysis of Existing Data Data from FracFocus EPA analyzed data on hydraulic fracturing-related chemical and water use based on chemical disclosures provided by oil and gas well operators in the FracFocus Chemical Disclosure Registry 1.0 between January 1, 2011, and February 28, 2013. FracFocus is the publicly accessible hydraulic fracturing chemical registry developed by the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission. Oil and gas well operators may voluntarily submit or, in some states, are required to submit well-specific data on chemical and water use to FracFocus. This analysis improved understanding of the chemicals and volumes of water used to hydraulically fracture oil and gas production wells in the United States and how chemical and water use vary in different locations across the country (3). 198 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

Spills Database Analysis To identify and characterize spills related to hydraulic fracturing, EPA analyzed data provided by nine states and industry (nine service companies and nine oil and gas well operators) for spills that occurred between January 1, 2006, and April 30, 2012. This analysis examined whether or not spilled fluids reached water resources, types of materials spilled, spill causes and sources, and containment and response activities (4).


Well File Review The EPA assessed well construction and operation data from a statistically representative sample of oil and gas production wells hydraulically fractured by nine service companies across the continental United States in 2009 and 2010. The objective of the study was to describe, for these wells: (1) well design and construction characteristics of hydraulically fractured oil and gas production wells, (2) the relationship of drinking water resources to hydraulically fractured oil and gas production wells, and (3) the number and relative location of barriers (e.g., casing and cement) that can prevent subsurface fluid movement. The sample of oil and gas production wells analyzed includes vertical, horizontal, and deviated wells in a variety of geological environments that are representative of different geographic areas and companies of various sizes (5).

Analytical Method Development Development of robust analytical chemistry methods is necessary to accurately and precisely determine the composition of hydraulic fracturing-related chemicals in ground and surface water, flowback and produced water, and treated wastewater. EPA developed and verified analytical methods for selected chemicals found in hydraulic fracturing fluids and wastewater. Chemicals selected for analytical method testing and development included acrylamide, alcohol ethoxylates and alkylphenol ethoxylates, glycols (diethylene glycol, triethylene glycol, tetraethylene glycol, 2-butoxyethanol and 2-methoxyethanol), and radionuclides (gross alpha and beta) (6–9).

Scenario Evaluations Source Apportionment Studies EPA characterized the potential impacts of hydraulic fracturing wastewater discharges to rivers and other potential sources of pollutants measured at public drinking water supply intakes on the Allegheny River in Pennsylvania. The work involved collecting river samples upstream and downstream of public water intakes and at centralized wastewater treatment facilities that process oil and gas wastewater, including wastewater from hydraulic fracturing. EPA used the river sampling data along with measured source discharge samples and source apportionment mathematical models to quantitatively apportion impacts 199 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

of discharges on downstream bromide, chloride, nitrate, and sulfate levels. This project describes the contribution of treated oil and gas wastewater to drinking water intakes on the Allegheny River and puts that contribution in the context of other sources, and improves understanding of the potential impacts from surface water disposal of treated oil and gas wastewater (10).


Subsurface Migration Modeling In collaboration with EPA, researchers at Lawrence Berkeley National Laboratories conducted studies to evaluate the potential for gas and fluid transport from fractured zones to drinking water aquifers. The analyses used subsurface migration models to investigate the potential effects of contaminant type, fluid pressure, and local geological properties on migration of contaminants and naturally occurring materials (11). Water Availability Modeling EPA studied how water withdrawals from surface or ground water used for hydraulic fracturing operations may affect drinking water availability. This study was conducted at various spatial and temporal scales in two regions that experienced concentrated hydraulic fracturing activity: the Susquehanna (humid) and the Upper Colorado (semi-arid) River Basins. The project combined an analysis of state and regional water use data and scenario analysis with information on local water availability. This analysis used available data to estimate how much water is used for hydraulic fracturing, where it comes from, and impacts on local sources at various levels of hydraulic fracturing activity in the two study regions (12). Surface Water Modeling EPA evaluated the potential impact from bromide in discharges from commercial wastewater treatment plants that treat oil and gas (including hydraulic fracturing) wastewaters in a number of scenarios. Data from commercial wastewater treatment plants in western Pennsylvania and river flow data were used to develop generic scenarios that illustrate the potential impacts from discharges into surface water (e.g., rivers and creeks) from commercial wastewater treatment plants that treat oil and gas wastewater (13).

Toxicity Studies EPA summarized existing data regarding toxicity and potential human health effects associated with chemcials found in hydraulic fracturing fluids and waste waters. The data was published in the draft Assessment and detailed information is available in a database available from EPA’s website (14). The data base makes accessible the information about the 1,173 hydraulic fracturing-related chemicals that were listed in the draft assessment. The product consists of a 200 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

series of spreadsheets with physicochemical and toxicological information pulled from several sources of information, including: EPI Suite, LeadScope, QikiProp, Reaxys, IRIS, PPRTV, ATSDR, among other sources. The spreadsheets also contain background information about how the list of chemicals was compiled, what the different sources of chemical information are, and definitions and descriptions of the values presented.


Retrospective Case Studies In five retrospective case studies (in Bradford Co., PA; Washington Co., PA; Wise Co., TX; Las Animas Co., CO; and Dunn Co., ND), EPA investigated instances of reported drinking water resource contamination in areas where hydraulic fracturing has occurred. The goals of these studies were to determine whether drinking water resources were contaminated, and if so, to better understand the potential source(s) of contamination nominated though a stakeholder process and prioritized based on a rigorous set of criteria to represent a wide range of conditions that may have resulted from hydraulic fracturing activities (15–19).

Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources The research projects were combined with an extensive review of literature that cited more than 950 relevant studies, and information gathered through stakeholder engagement efforts and public comment into EPA’s draft assessment. The report reflects the state of the science regarding the potential impacts of hydraulic fracturing for oil and gas on drinking water resources. The draft assessment was published in June 2015. It will be finalized after public comment and review by the Science Advisory Board. The final assessment will help move the science forward, improving understanding of the relationships between hydraulic fracturing activities and our drinking water resources, and identify important knowledge gaps. States, tribes, industry, and communities can use the information in the assessment to better understand vulnerabilities and to support decisions about how to best protect water resources and safeguard public health and the environment. To access more information about the EPA’s study, including the draft assessment and to subscribe to the EPA listserv, visit the study website at www.epa.gov/hfstudy. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency

201 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

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United States Environmental Protection Agency. Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources; EPA/600/R11/122; Washington, DC; 2011; pp 17−19. EPA’s Study of Hydraulic Fracturing for Oil and Gas and Its Potential Impact on Drinking Water Resources, United States Environmental Protection Agency. http://www2.epa.gov/hfstudy (accessed July 2, 2015). United States Environmental Protection Agency. Analysis of Hydraulic Fracturing Fluid Data from the FracFocus Chemical Disclosure Registry 1.0; EPA/601/R-14/003; Washington, DC, 2015. United States Environmental Protection Agency. Review of State and Industry Spill Data: Characterization of Hydraulic Fracturing-Related Spills; EPA/601/R-14/001; Washington, DC, 2015. United States Environmental Protection Agency. Review of Well Operator Files for Hydraulically Fractured Oil and Gas Production Wells: Well Design and Construction; EPA/601/R-14/002; Washington, DC, 2015. DeArmond, P; DiGregorio, A. Anal. Bioanal. Chem. 2013, 405, 4159–66. DeArmond, P; DiGregorio, A. J. Chromatogr. 2013, 1305, 154–63. United States Environmental Protection Agency. The Verification of a Method for Detecting and Quantifying Diethylene Glycol, Triethylene Glycol, Tetraethylene Glycol, 2-Butoxyethanol and 2-Methoxyethanol in Ground and Surface Waters; EPA/600/R-14/ 008; Washington, DC, 2014. United States Environmental Protection Agency. Development of Rapid Radiochemical Method for Gross Alpha and Gross Beta Activity Concentration in Flowback and Produced Waters from Hydraulic Fracturing Operations; EPA/600/R-14/107; Washington, DC, 2014. United States Environmental Protection Agency. Sources Contributing Inorganic Species to Drinking Water Intakes During Low Flow Conditions on the Allegheny River in Western Pennsylvania; EPA/600/R-14/430; Washington, DC, 2015. See eight studies listed under Scenario Evaluations at EPA’s Study of Hydraulic Fracturing for Oil and Gas and Its Potential Impact on Drinking Water Resources, United States Environmental Protection Agency. http://www2.epa.gov/hfstudy/published-scientific-papers (accessed October 3, 2015). United States Environmental Protection Agency. Case Study Analysis of the Impacts of Water Acquisition for Hydraulic Fracturing on Local Water Availability; EPA/600/R-14/179; Washington, DC, 2015. Weaver, J. W.; Xu, J.; Mravik, S. C. Scenario Analysis of the Impact on Drinking Water Intakes from Bromide in the Discharge of Treated Oil and Gas Wastewater. J. Environ. Eng. 2015, DOI: 10.1061/(ASCE)EE.19437870.0000968. United States Environmental Protection Agency. Compilation of Physicochemical and Toxicological Information about Hydraulic Fracturing-Related Chemicals (Draft Database); 202 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

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EPA/600/R-15/134; Washington, DC. http://cfpub.epa.gov/ncea/hfstudy/ recordisplay.cfm?deid=308341 (accessed September 24, 2015). United States Environmental Protection Agency. Retrospective Case Study in Northeastern Pennsylvania; EPA/600/R-14/088; Washington DC, 2015. United States Environmental Protection Agency. Retrospective Case Study in Southwestern Pennsylvania; EPA/600/R-14/084; Washington, DC, 2015. United States Environmental Protection Agency. Retrospective Case Study in Wise County; EPA/600/R-14/090; Washington, DC, 2015. United States Environmental Protection Agency. Retrospective Case Study in the Raton Basin, Colorado; EPA 600/R-14/091; Washington, DC, 2015. United States Environmental Protection Agency. Retrospective Case Study in Killdeer, North Dakota; EPA/600/R-14/103; Washington, DC, 2015.

203 In Hydraulic Fracturing: Environmental Issues; Drogos, Donna L.; ACS Symposium Series; American Chemical Society: Washington, DC, 2015.

Overview of US EPA's Study of the Potential ... - ACS Publications

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