The impact of horizontal drilling and hydraulic fracturing on groundwater quality in the Cline shale play is not believed to be permanent, new research from the University of Texas at Arlington (UTA) suggests.
The research is the first to analyze the groundwater quality in the Cline shale region of West Texas before, during and after the expansion of unconventional exploration and production.
Researchers found that water samples from private wells contained chlorinated solvents, alcohols and aromatic compounds exclusively after multiple unconventional oil wells had been activated within 3.1 miles of the sampling sites.
Large fluctuations in pH and total organic carbon levels also were detected in addition to a gradual accumulation of bromide.
These changes and levels are abnormal for typical groundwater quality, said Kevin Schug, the study’s lead author and UTA’s Shimadzu Distinguished Professor of Analytical Chemistry and director of UTA’s Collaborative Laboratories for Environmental Analysis and Remediation (CLEAR), in an April 26 press release.
However, the results also suggest that containment from unconventional drilling may be variable and sporadic, not systematic, and that some toxic compounds associated with areas of high unconventional drilling may degrade or become diluted within the aquifer over time.
The study also indicated that contamination pathways are complex; various toxic compounds were detected in groundwater seemingly at random times in areas of high drilling activity. Schug said that more research is needed to precisely quantify and understand contamination cycles as well as to understand aquifer resilience to pollutants.
A Note to the Granddaughters
I generally take Sophia -- she will be two years old this June -- to the park every day for about an hour or so. I try to keep it varied and interesting. Today we took five dice. Sophia loves to play Yahtzee. She has no idea what she's doing but she loves to put the five dice in a cup and roll them, and then throw her arms up, and yell "Yahtzee" when she rolls a Yahtzee. She gets a Yahtee on every roll.
On the way home, Sophia was getting antsy, so I gave her the five dice to play with on her tray on her stroller. About half-way home I noticed that one die was missing.
I feigned my irritation, telling Sophia we were going to have to go back over the ground covered, and look for the missing die. She was very serious, and, she, too, leaned out over the stroller, to help look for the missing die.
We had backtracked about a block when I noted she was holding a die in her hand, and there were still the original four in her tray.
Putting "2 and 2" together, it was clear we were never missing the fifth die. Sophia had put it in her mouth and that's where I had not checked. I guess to keep from getting in trouble, when I feigned irritation, she kept her mouth shut and continued the charade of looking for the lost die, and then when the time was right, put the "lost" die in her hand so I could see it.
Never a dull moment.