New study identifies organic compounds of potential concern in fracking fluids
June 30, 2015 Joseph Ryan
A new University of Colorado Boulder study that looked at hundreds of organic chemical compounds found in hydraulic fracturing, or fracking, shows that 15 may be of concern as groundwater contaminants based on their toxicity, mobility, persistence and frequency of use.
Using a new groundwater fast track framework scenario for tracking compounds in groundwater, the team is able to predict which chemicals would have 10 percent or more of their initial concentrations remaining after moving roughly 300 feet through an aquifer, says CU-Boulder Professor Joseph Ryan, lead author in the study.
CUT 1 “Of those 659 we looked for the ones that would actually be relatively mobile and persistent in the groundwater and got that list down to about 41 compounds. (:12) Of those we could narrow it down even further to 15 that were relatively frequently used in hydraulic fracturing fluids. (:21) And then even going further down of those 15 only 9 would really be considered compounds that have some concern with respect to toxicity.” :31
The 308 feet distance criteria for the study is used because that is the average state “setback” distance between a fracking well and a drinking water well, says Ryan.
Fracking involves mixing water, sand and various chemicals that are then pumped into wells at high pressure to create fissures in subterranean shale layers to free natural gas. The fluid contains a variety of chemicals to inhibit equipment corrosion and reduce friction, among other things.
CUT 2 “We think that the main message to get out of our paper is that there certainly are some compounds that we should be paying attention to. That we should be looking for these compounds as potential tracers of whether or not hydraulic fracturing fluid is actually showing up in any places where we don’t want it to be showing up.” (:20)
But Ryan also says it should be noted that there are hundreds of chemicals in fracking fluid that are not viewed as a significant threat to drinking water.
CUT 3 “On the flip side we want to come back to that point we don’t want people to be using the fact that there are hundreds of compounds that have been used in hydraulic fracturing fluid as an alarm tactic.” (:14)
The compounds screened were identified in large part from the nationwide FracFocus Chemical Disclosure Registry used by many states where companies disclose chemical information about most of the ingredients used in fracking.
The team obtained data from more than 50,000 wells in Colorado, North Dakota, Pennsylvania and Texas since 2011, says Ryan, a faculty member in civil, environmental and architectural engineering.