Researchers discover contamination in Eagle Ford Shale region

Lawrence Goodwyn

In a recent study, UT Arlington researchers detected contaminants in South Texas drinking water that could be hazardous if allowed to accumulate.

Scientists Zachariah Hildenbrand and Kevin Schug said the presence of these chloride and bromide abnormalities in the Eagle Ford Shale region drinking water could be related to hydraulic fracturing or other unconventional gas development techniques.

Schug is the director of UT Arlington’s Collaborative Laboratories for Environmental Analysis and Remediation, and Hildebrand is a science advisor to the laboratories.

By analyzing how much of a certain element is present in a water sample, scientists can determine whether the water is interacting naturally with its environment or if human activity has affected it.

The researchers said high levels of chloride and bromide can occur naturally, but man-made instances of contamination require attention. The bromide and chloride concentrations in the region’s water are not harmful at the current levels, but Hildenbrand said they could become a problem if they continue to increase.

Hildenbrand said one cause of the abnormalities could be related to unconventional gas development techniques such as hydraulic fracturing, also known as “fracking.”

“What a lot of outside literature has pointed to is that the faulty well casing during the hydraulic fracturing process allows the oil that should be pumped to the surface from the wells to permeate laterally into ground drinking water,” Hildenbrand said. 

Although the Eagle Ford Shale region’s water is safe right now, contamination due to faulty well casing can still be an issue. In the Marcellus region, another region of shale in Northeastern America, 7 percent of oil wells fail and leak contaminants into the surrounding rock, according to Hildenbrand. While he said this is a relatively low failure rate, the effects can cause alarm when there are thousands of drinking water wells in the same area.

Hildenbrand said that only 5 years ago, little research went into fracking contamination. 

“That’s why we do this research, because everyone seems to have an opinion and this debate is highly fueled by emotion as opposed to actual evidence and data, and so we want to change that narrative,” Hildenbrand said. 

The scientists plan to use the information they’ve been collecting to generate a strong knowledge base about the contaminants around unconventional gas development sites. 

“[Chloride and bromide ratios are] really just a diagnostic tool,” Schug said. “If you understand a range of chloride to bromide concentrations you can start to understand whether some water has natural interactions with the geology or some extremity such as industrial processes or other things in the area can affect its quality.”

Hildenbrand said scientists must make sure that nearby actions such as road salting, which can increase the chloride concentration of samples, have not skewed their results. 

In the future, Schug said scientists will need to work with and observe the oil and gas industries closely to determine what is causing this minor change in contamination ratios, and to prioritize gathering more information about these contaminants and their source.

“I think what you need is a critical mass of information for a government policy to be formed, and [right now] there’s a limited amount of research being put into understanding the potential effects of the oil and gas operations,” Schug said.