Melanie Sattler, civil and environmental engineering assistant professor at U. Texas-Arlington, used a different kind of sampling method when searching for pollutants from natural gas wells.
Sattler said she found high levels of several pollutants including the potentially cancerous Benzene when using her method.
One location Sattler surveyed was in Dish, Texas. Dish was one of the first locations to find high levels of Benzene in and around compressors. Other locations were in Fort Worth.
Sattler said she used a testing method called Dispersion Modeling, which takes readings over the course of a year. The normal test involves a canister that pumps air samples for a predetermined amount of time. The canister is then sent to a lab for analysis, she said.
“A sample could be taken for two hours, but those two hours may not be typical,” Sattler said.
High winds and meteorological turbulence can cause significant dilution to the readings. Low winds and meteorological turbulence would cause high readings, Sattler said. It takes time for toxins to touch ground from on top of the stack, she said.
“The ideal thing would be to measure what is coming out of the stack,” she said.
Sattler said sometimes people would take readings based on smell or by taking readings over a very short time.
“There are people at [The Texas Commission on Environmental Quality] that would know better,” she said.
Rick Trice, Fort Worth Gas Well Divisions Planning and Development assistant director, said Fort Worth will conduct a full survey of approximately 500 sites.
A $600,000 contract with Eastern Research Group, Inc. for The Fort Worth Air Quality Study was approved by the Fort Worth City Council Tuesday night. The contract would give the company the task of testing emissions at each of the locations.
Fort Worth Mayor Mike Moncrief said this study will be looked at by people in other shale areas of the country.
“This survey is going to be a lot bigger than Fort Worth or Tarrant County,” he said.
Moncrief said the city will release information as it receives it. He said if a danger is found, the city will act immediately.
Carrizo Oil & Gas, Inc., which operates the UTA wells, operates one in Fort Worth.
“If the city wants to conduct surveys, Carrizo will welcome the opportunity for cooperation,” said Dan Petri, Carrizo Oil & Gas, Inc. Barnett Shale production manager.
Petri said the Texas Commission on Environmental Quality frequently conducts surveys at the UTA gas wells. It also has toured the UTA facilities to gain an understanding of operations, he said.
Petri said all surveys to date have indicated no violations.
“What I see in general is a combination of visual surveys and camera surveys, with sampling if required,” he said. “I expect ongoing surveys to continue in the future on the same basis.”