The organic side of fracking

The answer - organic compounds contained in insecticides (gluteraldehyde), make-up removers (petroleum distillates), and antiperspirants (isopropanol) are some of the same chemicals found in the fracking fluids injected into drilling wells to break down shale rock and release natural gas. Both gluteraldehyde and isopropanol have known toxic effects in humans, including causing asthmatic and respiratory difficulties. However, whereas environmental regulations are already in place to manage waste from companies producing household goods, little regulation exists within the burgeoning fracking industry to prevent these and other organic chemicals from leaking into surrounding groundwater or polluting the air (except for a few state regulations).

Although both organic and inorganic compounds can be toxic, until now research has heavily focused on the latter and their contamination effects. To remedy this, a recent study¹ by Ferrer and Thurman in Trends in Environmental Analytical Chemistry highlighted how little we know about organic chemical leakage and laid out key experimental methods to identify many of the organic compounds in fracking fluid. This is a great starting point to motivate more scientists to collect the necessary data to eventually connect the organic chemicals used in fracking to nearby groundwater. This achievement would inform policy recommendations about restrictions for the fracking industry, who have generally done what they've wanted and answered questions later.

With chemically treated water comes great responsibility

Fracking consists of three main processes: 1) identify a shale formation and drill a mile-deep well into the rock; 2) inject a mix of water, sand, and chemicals, known as fracking fluid, into the well at high pressure to break down the shale rock to release trapped natural gas (usually methane); and 3) relieve the pressure so the natural gas can be collected along with the waste water that must be treated or carefully disposed of. Although the fracking fluid is over 99 percent water and sand, the remaining one percent of organic and inorganic chemicals is critical to improve the fluid's viscosity, reduce friction against the well and rid it of clogging bacteria, and act as a solvent to dissolve rock and remove natural gas more efficiently (a general list of chemicals included can be found here).

Vertical drilling has been going on for decades, however recent technological advancements have allowed for horizontal fracking and has fueled the recent natural gas boom. This modern method extends wells in horizontal directions once it has reached the shale formation to access more volume of rock (see diagram to the left), significantly increasing the return for a given well. However, this method is the major reason for increased water contamination issues, as horizontal wellbores cover more territory beneath the surface and increase the likelihood of gas or chemical leakage.

These three steps require an immensely complicated operation, which means that plenty of things can go wrong along the way. Injected fracking fluid, full of the various toxic chemicals, can seep into water aquifers after fracturing the shale or due to cracks in the well casing. In addition, fracking releases water that has been confined in the geologic shale formation for millions of years, which contains naturally occurring radioactive and heavy metal elements that leak into the water and air. Water waste management is also largely unregulated. The list goes on and on.

To date, most research has investigated inorganic water contamination and pollution, mainly due to elements native to shale formations that find freedom once the drilling well cracks open million-year-old deposits. A new study has correlated increased indoor air concentrations of radon, a radioactive element trapped underground as a gas, to proximity to nearby fracking sites^2,. Other elements native to the geologic formations include aluminum, chlorine, iron, and manganese, all of which have been shown to have high concentrations in the waste water, threatening groundwater contamination if left unregulated (see Reference 1 for complete details). In comparison, almost no research has examined the organic chemical composition of the waste water or nearby water systems to understand how the fracking fluid itself may be contributing to contamination.

But every intensive industrial process upon which our society relies has possible environmental and public health consequences, right? The difference is that no previous policy exists that pertains to fracking, and companies have taken advantage of our general avarice to begin something of a natural gas revolution before policymakers could gather themselves to provide limits. Public awareness of fracking's dangers appear to be growing faster than policymakers' concerns - the unregulated industrial boom has led to many pieces of anecdotal evidence and lawsuits about its perils.

But there's a reason for this, and scientists can help. We don't know much about how fracking pollutes and we need evidence! Generating policy that regulates fracking is difficult mainly because of the immense diversity in chemicals and methods used from state to state and company to company. Up to this point, businesses have hidden the detailed composition of their fluids for proprietary and competitive reasons. Although disclosure is becoming more common, specific limits have to be determined for each organic or inorganic material used. To accomplish this, we need scientific methods to identify organic compounds in fracking fluids and connect them to increased concentrations in nearby groundwater or air to provide support for stricter regulations.

Searching water samples for an answer

The new study by Ferrer and Thurman outlines a way to do just that for organic compounds. After a thorough review of the current research on fracking chemicals and reported leaks, the authors surprisingly conclude that little to no effort has focused on tracking the organic chemical cocktail included in all fracking fluids. Inorganics have been tracked in several studies, and problems with leakage have been shown to occur.

To address the paucity of data about organic chemicals, the authors lay out experimental methodology to test for such chemicals in water samples. Using fancily-named techniques - chromatography and mass spectrometry - the authors show how each analytic technique can identify specific chemical compounds in the fracking fluids. For example, mass spectrometry charges the fluid sample and shoots it through a magnetic field in its gas form; particles with different mass bend their trajectory to different degrees in the field, allowing for the identification of different inorganics and metals that mostly arise from the shale formation itself.

Combining the above method with chromatography - partitioning different constituents in the fluid by their speed, then using mass spectrometry to separate masses - allows for the identification of organic chemicals from the fracking fluids, which the authors emphasize has not been explored at all to date. The combined method reveals at least 25 percent of the organic compounds seen in most fracking fluids, which is a good start. These include biocides to prevent bacteria growth, acids to help dissolve rock, surfactants used in detergents to increase viscosity, and many more (see Table I in Reference 1).

The hope is that laying out the procedures will motivate other scientists to explore the fluid composition so the scientific community can reach a consensus more quickly about environmental impacts. The next step would be to test groundwater close to fracking sites and correlate its composition with that seen in fracking fluids. This hard data would be a convincing piece of evidence to push for stricter regulation.

Hydraulic fracturing has a clear role to play in the world's energy future: the business creates jobs for the home country, natural gas consumption will reduce reliance on the volatile Middle East, and natural gas emits about half the carbon dioxide emissions per unit energy compared to coal. But problems arise when we place economic priorities above public health and environmental ones. The bottom line is that we don't have the evidence yet to condemn fracking practices as they are, although earthquakes in Oklahoma are becoming convincing!³ The research outlined above provides a road map for scientists to collect more data to shape policy. This path will allow us to develop a fracking industry while protecting the citizens and towns surrounding the operations. Fracking is not an intrinsically hurtful energy alternative, but it can be if we follow the smell of gas and step on those around us in the process.

References

1. Ferrer, I. and Thurman, E.M. "Chemical constituents and analytical approaches for hydraulic fracturing waters". Trends in Environmental Analytical Chemistry, 5, 18-25 (2015).

2. Casey J.A. et al. "Predictors of indoor radon concentrations in Pennsylvania, 1989-2013." Environmental Health Perspectives, April 9 2015.

3. Holland, A.A. "Earthquakes triggered by hydraulic fracturing in south-central Oklahoma." Bulletin of the Seismological Society of America, 103(3), 1784-92 (2013).

Photo Credit

Hydraulic fracturing photo courtesy of Hike395 at Wikipedia

Hydraulic fracturing diagram courtesy of Mikenorton at Wikipedia