Barnett Shale

Study finds elevated levels of metals, chemicals in Barnett Shale water samples

The UTA study found elevated levels of numerous metals and chemical compounds associated with hydraulic fracturing in the Barnett Shale, but stopped short of identifying drilling as the source of contamination.
The UTA study found elevated levels of numerous metals and chemical compounds associated with hydraulic fracturing in the Barnett Shale, but stopped short of identifying drilling as the source of contamination. Star-Telegram/David Kent

Researchers from the University of Texas at Arlington have found elevated levels of numerous metals and chemical compounds associated with the hydraulic fracturing process in public and private water wells throughout the Barnett Shale.

A peer-reviewed study published in the scientific journal Environmental Science & Technology is careful not to identify drilling as the source of contamination, but the authors say their study should “be an impetus for further monitoring and analysis of groundwater quality.”

“We can’t definitely say that it affected water here, but we can’t rule out that it was not the culprit,” said Zacariah Hildenbrand, one of the lead authors of the study who collaborated with UTA. “It is more likely that it has had an effect on water quality.”

The UTA study analyzed 550 groundwater samples from wells that draw from the Trinity and Woodbine aquifers overlying the 5,000 square miles that make up the Barnett Shale in North Texas. It is broader than UTA’s 2013 study that looked at samples from 100 wells.

UTA associate chemistry professor Kevin Schug, another of the paper’s authors, said he hoped that the study would be used to make changes in the drilling process if needed.

He said the research could be used as a “springboard for studies” that would pinpoint the impact of various aspects of the unconventional drilling process on groundwater activity.

“It’s our job to remain balanced and report what we found in an objective, scientific fashion and the fact of the matter is that many of these compounds are in some way associated with that process,” Schug said.

Environmentalists said UTA’s study proves that contamination from hydraulic fracturing, or fracking, is more common than what was suggested in a recent draft study released by the Environmental Protection Agency.

The EPA study said that hydraulic fracturing has not caused widespread harm to drinking water in the United States, but it also warned of potential contamination of water supplies if safeguards are not maintained.

“I would argue that 550 wells over many square miles meets any reasonable definition of widespread,” said Alan Septoff, strategic communications director for Earthworks, an environmental group. “It is not pollution from one well, but it is pollution from many wells.”

Industry representatives quickly pointed out that the study does not definitively link the drilling process to the elevated levels of the chemicals and compounds that were found.

“The authors specifically say that they cannot link contamination to unconventional oil and gas activity,” said Dave Quast, a spokesman for Energy In Depth, an industry group. “Activist groups and some media are trying to manufacture a fracking link that the data don’t definitively support.”

Ed Ireland, executive director of the Barnett Shale Energy Education Council, another industry group, pointed out that some of the chemicals could be coming from sources such as agriculture.

“You can’t take [that] leap of faith,” Ireland said. “You need to do a more comprehensive study to link the two.”

Broader testing ground

The Trinity and Woodbine aquifers are home to more than 20,000 so-called “unconventional drilling wells” where hydraulic fracturing is used. Fracking involves the injection of water, sand and chemicals underground to break apart shale rock and free trapped oil or gas.

The UTA study looked at 550 samples taken from 350 water wells serving residential purposes, 59 samples from agricultural water wells and 141 from municipal or public water supply wells servicing communities throughout the Dallas-Fort Worth area.

About 83 percent were taken from wells tapping aquifers located above the Barnett Shale formation. The samples were taken without prior knowledge of drilling activity in Montague, Wise, Parker, Hood, Tarrant, Somervell, Johnson, Hill, Ellis, Dallas, Denton, Collin and Cooke counties.

The sites were selected on the basis of well owner participation and their ability to collect untreated water that would represent the underlying aquifers, the study stated.

The study found elevated levels of 10 different metals as well as the presence of 19 chemical compounds including what is known as BTEX, or benzene, toluene, ethyl benzene and xylenes. These compounds are associated with oil and gas processing activities.

Schug said they found at least one BTEX compound in 381 of the 550 samples and that in a handful the benzene levels exceeded the maximum levels established by the EPA.

“These compounds are carcinogenic,” Hildenbrand said. Benzene “is a nasty, nasty chemical. You wouldn’t want to be drinking any amount of that.”

The study also found elevated levels of methanol and ethanol, both of which are used extensively in unconventional drilling as anti-corrosive and gelling agents, the study reported.

Finding benzene was a new wrinkle from the 2013 UTA study. That report, which Schug directed, did not find volatile organic compounds such as benzene. The earlier report did find contaminants such as arsenic and selenium in groundwater near natural gas well sites.

Schug said this was a much broader study and that they have been refining their methods over time. He said they didn’t have “any expectations” but he was surprised by the BTEX contamination.

Other studies

The UTA study hits on concerns made in previous research efforts.

The recent EPA assessment found specific instances where poorly constructed drilling wells or improper wastewater management affected drinking water, but said the number of cases was small compared to the large number of wells that use the hydraulic fracturing process.

“We conclude there are above and below ground mechanisms by which hydraulic fracturing activities have the potential to impact drinking water resources,” the EPA said. But, “we did not find evidence that these mechanisms have led to widespread, systemic impacts on drinking water resources.”

The threat of water contamination by fracking and related oil and gas processes has been an ongoing issue in Texas.

The most celebrated case was in Parker County, where resident Steve Lipsky’s video of flaming water sparked an emergency order by the EPA in late 2010. The problem had been blamed on a nearby well drilled by Fort Worth-based Range Resources.

The Texas Railroad Commission investigated and conducted tests of Lipsky’s well and at a 2011 hearing cleared Range, which had steadfastly denied contaminating the groundwater. In 2012, the EPA withdrew its emergency order, although Range agreed to continue testing 20 nearby water wells every three months for a year.

A study released last year blamed faulty drilling practices — but not hydraulic fracturing itself — as the primary cause of water contamination in the Barnett Shale.

In that study, scientists from Duke, Stanford and three other universities studied more than 130 water wells in North Texas and the Marcellus Shale in Pennsylvania. Their findings suggested that methane gas found in water stems from faulty well casings and cement construction designed to protect groundwater during drilling.

Hildenbrand, who is the owner of Inform Environmental, the private company that helped coordinate the study and conducted the sample collection, said that they are “at the ground floor here trying to understand” what is going on.

“If there is a problem, how do we fix it? We’re not trying to shut down drilling,” he said.

Max B.Baker, 817-390-7714

Twitter: @MaxbakerBB