BASELINE GROUNDWATER QUALITY TESTING NEEDS IN THE EAGLE FORD SHALE REGION

As the pace of drilling in the Eagle Ford shale increases, so does the potential for groundwater contamination incidents. The goals of this analysis are (1) to determine whether existing baseline groundwater quality data in the Eagle Ford shale region is adequate to provide a comparison to potential future contamination from oil and gas development and (2) to define an appropriate and cost-effective list of parameters that will aid in strategic planning of baseline ground water quality testing in the Eagle Ford shale region for the same goal.

First, a list of potential testing parameters is defined using case studies of proposed groundwater contamination. Second, formation water chemistry in the Eagle Ford shale region is compared to groundwater chemistry in the counties of the Eagle Ford shale region to determine which chemical indicators demonstrate potential to consistently detect contamination. Third, statistical power analysis is used as a guideline to decide whether more samples are needed for each testing parameter in each county in the Eagle Ford shale region. Next, known health effects of each testing parameter are described in order to highlight potential pollutants that should be prioritized in a sampling initiative. Finally, testing costs are reported to introduce a perspective about microeconomic choices affecting which stakeholders take responsibility for baseline groundwater quality testing.

These tasks led to the findings that some of the most dangerous potential pollutants, including methane, total petroleum hydrocarbons, nitrate, volatile organic compounds, polycyclic aromatic hydrocarbons, alpha particles, beta particles, and gamma radiation, are poorly characterized in the region, if at all. Furthermore, testing these parameters is more expensive than testing less hazardous ones. Water well owners may be unable to afford the expense of testing these parameters. Therefore, a testing initiative facilitated by agencies, industry, or other organizations may be more efficient at establishing a regional baseline for these high priority, expensive tests. As such, the framework and analysis presented here can be used by groundwater managers in the Eagle Ford shale region to develop baseline sampling strategies tailored to specific counties in the region.