Grantee Research Project Results

Experimental Analysis of the Environmental Behavior of Hydraulic Fracturing Fluid Compounds Prioritized by Potential of Environmental or Health Risk

EPA Grant Number: FP917451
Title: Experimental Analysis of the Environmental Behavior of Hydraulic Fracturing Fluid Compounds Prioritized by Potential of Environmental or Health Risk
Investigators: Dehart, Jessica Nichole
Institution: University of Colorado at Boulder
EPA Project Officer: Packard, Benjamin H
Project Period: August 1, 2012 through July 31, 2015
Project Amount: $84,000
RFA: STAR Graduate Fellowships (2012) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Environmental

Objective:

As the practice of hydraulic fracturing rapidly expands, there is increasing concern about potential environmental impacts, including effects on ground water quality. Challenges to understanding potential impacts include limited data on the environmental behavior of fracturing fluid additives as well as insufficient analytical methods to detect evidence of transport. This research experimentally will derive the degradation kinetics and subsurface transport mechanisms of prioritized categories of organic contaminants, and subsequently build a predictive model of the environmental behavior of fracturing fluid organic additives introduced to shallow ground water drinking resources.

Approach:

Organic compounds will be selected for experimental study of degradation and transport out of two possible categories: potential environmental risk and potential fracturing fluid tracers. Column tests will be used to inject pulses of known masses of the selected organic compounds in addition to a conservative tracer into an aquifer material. To compare the relative importance of sorption to degradation as primary removal mechanisms, batch reactors will be used to experimentally derive degradation rates under anaerobic conditions. The experimentally derived physiochemical data then will be applied to a ground water model to test the fate and transport of the compounds under varying subsurface conditions.

Expected Results:

Given the large number of chemical additives used in hydraulic fracturing fluids, it is not practical to conduct a comprehensive analysis in cases where contamination is suspected. The fate and transport model can identify compounds with high likelihood for transport and persistence out of the hundreds possible, given the hydrogeologic conditions for a particular site. Additionally, the model may be applied to identify nonconservative organic compounds as tracers for evidence of fracturing fluid migration. The use of organic compounds as tracers could increase confidence in assessment of the environmental impact of hydraulic fracturing, particularly in cases where baseline water quality data are not available. This is due to the fact that many of these compounds would be unlikely to appear in water samples due to the natural background geochemistry or alternative anthropogenic sources.

Potential to Further Environmental/Human Health Protection
Water and energy are two basic needs of society. There is a great amount of potential to further develop natural gas as a domestic energy source; however, the risk to human and environmental health is not fully understood. Improved knowledge about the environmental behavior of fracturing fluid compounds, as well as more reliable analytical methods such as the use of organic tracers, may allow for better management by environmental regulators regarding potential contamination of ground water resources.

Supplemental Keywords:

hydraulic fracturing fluids, ground water contamination, contaminant transport modeling

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.