A University of Colorado study looking at the toxicity, mobility, persistence and frequency of occurrence for hundreds of organic compounds deployed in hydraulic fracturing indicated that 15 could be of concern as potential groundwater contaminants.
CU professor Joseph Ryan, principal investigator on the project funded through a $12 million grant from National Science Foundation, drew on data obtained from more than 50,000 wells in Colorado, North Dakota, Pennsylvania and Texas since 2011.
A total of 659 organic compounds used in fracking were screened, utilizing a fast groundwater transport scenario. Researchers predicted that 41 of the 659 organic compounds screened would have 10 percent or more of their initial concentrations remaining at a transport distance of about 300 feet.
That’s s the average state “setback” distance between a fracking well and a drinking water well in the United States, Ryan said.
Corresponding study author Jessica Rogers, a CU-Boulder doctoral student in civil, environmental and architectural engineering, said that of those 41 compounds, 26 predicted to be mobile and persistent were extremely rare, and were identified in less than 50 of the 50,000 FracFocus Chemical Disclosure Registry entries examined for the CU study.
FracFocus is used by companies in many states, including Colorado, to disclose chemical information about most of the ingredients used in the fracking process at individual wells.
‘The big message’
Fracking is the process of injecting a pressurized mixture of water, sand and chemicals into well bores to free up deep-underground petroleum deposits. Energy companies use a wide variety of chemicals to limit equipment corrosion and reduce friction, among other things.
Of the 15 compounds that were found to be of concern as groundwater contaminants in the CU study, only two — naphthalene and 2-butyoxyethanol — were identified on more than 20 percent of the 50,000 FracFocus reports.
Only four were identified on more than 5 percent.
“We like to think the most significant thing is that people should be aware that we can make predictions about how these chemicals may behave in the groundwater, and make some estimates of which ones would be of greatest concern,” Ryan said Thursday.
“Up until this point, all of the focus had just been on the presence of toxic compounds, without any thought about whether or not they would actually get anywhere if they were released.”
Beyond the relative toxicity of individual compounds, said Ryan, a faculty member in the Department of Civil, Environmental and Architectural Engineering, his team’s work showed that “even if some were spilled or released from a faulty well casing or something like that, a lot of them wouldn’t really get anywhere.
“They would … never make it to a water well, or they would break down before they got there — and usually when they break down, they become less toxic. That’s the big message.”
‘Pretty benign’
The CU study, appearing online in Environmental Science & Technology Letters published by the American Chemical Society, comes just less than a month after an Environmental Protection Agency report to Congress examining the incidence of contaminated drinking water supplies caused by fracking. The study found that while it has occurred, it has not been “widespread” or systemic.”
Ryan acknowledged the EPA report, but added, “The other problem we always have with groundwater is, if it is contaminated, it is going to be contaminated for a long time. It doesn’t just flow downstream. It’s moving slowly.
“The compounds we might release into groundwater have the potential for being there a long time.”
Randy Hildreth, Colorado director for Energy in Depth, a research, education and public outreach campaign organized through the Independent Petroleum Association of America, said the study’s findings, “hypothetical scenarios aside,” were “pretty benign.”
He added, “That’s what you would expect after President Obama’s EPA spent five years studying hydraulic fracturing and concluded it doesn’t pose a major risk to drinking water.”
Co-authors on the paper included CU researcher Troy Burke and Cal Poly Pomona Associate Professor Stephen Osborn. Additional funding came from a U.S. Environmental Protection Agency STAR fellowship to Rogers.
Charlie Brennan: 303-473-1327, brennanc@dailycamera.com or twitter.com/chasbrennan
