Texas drinking water tainted by natural gas operations, scientists find | Dallas Morning News

The shale-gas boom of recent years has contaminated drinking-water wells in North Texas’ Barnett Shale and the Marcellus Shale in Pennsylvania, a study published Monday concludes.

The study, by researchers from five universities, concludes that neither drilling itself nor the hydraulic fracturing that follows it is directly to blame.

Instead, gas found in water wells appeared to have leaked from defective casing and cementing in gas wells, meant to protect groundwater; or from gas formations not linked to zones where fracking took place.

“Our data do not suggest that horizontal drilling or hydraulic fracturing has provided a conduit to connect deep Marcellus or Barnett formations directly to surface aquifers,” the authors wrote.

The study, published in Proceedings of the National Academy of Sciences, adds to a growing body of science that examines the environmental impacts of natural gas production, which has seen a rush of drilling and processing in numerous states over the past decade.

In an email, lead author Thomas Darrah of Ohio State University said tracing the blame to well construction problems instead of fracking offers hope of protecting groundwater supplies.

“This is relatively good news because it means that most of the issues we have identified can potentially be avoided by future improvements in well integrity,” said Darrah, who teaches in the School of Earth Sciences at Ohio State.

The study’s other authors are scientists from Duke University, Stanford University, Dartmouth College and the University of Rochester.

Barnett Shale

The U.S. gas boom began a decade ago in the Barnett Shale region, which starts in West Dallas and covers about 5,000 square miles across parts of 18 counties. Texas regulators have issued 20,493 Barnett Shale drilling permits since 2005, many in residential neighborhoods.

No drilling has taken place in Dallas, although other Dallas County cities have wells.

To extract gas from shale thousands of feet below the ground, producers fracture the rock by pumping in millions of gallons of water, sand and chemicals under high pressure.

Critics say the practice poses risks of gas and chemicals leaking into water supplies. Denton residents will vote Nov. 4 on a proposal to ban fracking in that city.

The gas industry and many regulators, including the Texas Railroad Commission, defend the practice, saying fracking has revolutionized the U.S. energy mix without endangering health or the environment.

The commission had not reviewed the new study last week. “Our staff has no comment on a study they have not seen,” spokeswoman Ramona Nye said.

The researchers sought to find the origins of gas found in water wells and to determine how it got there.

They took samples from wells in which gas levels had risen over time, clustered in seven locations in western Pennsylvania’s Marcellus Shale and one in the Barnett region.

Sufficiently high concentrations of natural gas in drinking water can put harmful fumes in homes, creating the risk of a fire or explosion.

The Barnett Shale samples were taken in southern Parker County, not far from a home whose owner, Steve Lipsky, is being sued for defamation by a gas company, Range Resources. The U.S. Environmental Protection Agency has blamed the company for causing gas to infiltrate Lipsky’s water.

Isotopes studied

The university scientists analyzed water samples for amounts and isotopes of hydrocarbons and noble gases, a group of inert elements that includes helium, neon and argon. Isotopes are versions of the same element whose nuclei have the same number of protons but different numbers of neutrons.

The analysis yielded “signatures” indicating where the gas came from and how it reached the aquifers. The researchers said they believed it was the first time noble gas isotopes had been used to produce such an analysis.

In some cases, the gas came from shallower formations unrelated to fracking, said Darrah, the Ohio State researcher. In others, he said, shale gas traveled up a gas well and then leaked into the aquifer through faults in the well.

But the gas “is definitely not released by hydraulic fracturing breaking out of the shale and migrating into groundwater,” he said.

If the study had found that fracking were directly releasing gas into aquifers, he said, that “could have other, later, and potentially more serious environmental implications.”

Range Resources’ defamation suit against Lipsky stemmed from his release of a home video that showed flaming water coming out of his garden hose.

A complaint from Lipsky in 2010 led to an EPA emergency order that held Range responsible for gas in Lipsky’s water well. Range, based in Fort Worth, denied that its wells were the source.

The Railroad Commission exonerated Range after a hearing in which the gas company and commission staff presented evidence, but neither Lipsky nor the EPA took part.

The EPA later withdrew its order in an agreement that was viewed as heavily favorable to the company. The EPA’s inspector general later determined that the original order had been properly issued.

Follow Randy Lee Loftis on Twitter at @RandyLeeLoftis.

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