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Compared to the magnitude of unconventional oil and gas development activity that has been performed by industry, the amount of research to assess its potential environmental impact has been miniscule. Can the process have a deleterious impact if not well managed? Can it be performed in a responsible manner?
Recently, our research consortium (http://clear.uta.edu) published an article that describes a time-series analysis of groundwater quality in close proximity to expanding unconventional oil and gas development (UD) activity (1). This study is essentially the first of its kind. For several years, the few active researchers in this field have expounded on the need for baseline measurements and a time-series analysis. Our team was able to accomplish this task, and the release of the study last week (2) triggered a wide range of reports from various media outlets. The disparities in the interpretation of our work by the different reporters was expected, but still vexing.
Our study found sporadic and ephemeral (not systematic) changes in levels of basic water quality parameters (pH and total organic carbon), different volatile organic compounds (dichloromethane and alcohols), metals (iron), and ions (bromide) in a cluster of rural West Texas water wells as UD activity within a 5-km radius expanded from one to 15 oil extraction wells over the four phases of this 13-month study. This study was a combined effort of individuals from three universities, a private company, and multiple independent consultants. The data we collected were responsibly interpreted and reported in an unbiased fashion, consistent with our previous publications on this topic (3–5).
Our published conclusions were tempered with an understanding that there are limitations to this and any study, but some critics have decided they should try to seize on these results to distort and discredit our work. Here I would like to address a few of the valid queries made by these critics. These questions were asked by some of the responsible media outlets, but the answers were not conveyed in their entirety. I believe that an explanation here can also be educational about the complexity of this type of research. Other statements from less-responsible outlets bordered on attempts simply to call the validity of our research team and methods into question. Those are simply unfounded and will be addressed in a separate communication.
Standing the middle ground on a charged topic like this is not easy. Environmental activists just want UD to be shut down. Industry representatives preach that there are absolutely no environmental concerns associated with the UD process. In most things that are important, the truth is rarely as simple as the extreme views convey it to be, and that is true here. We want to provide reliable scientific information so that people can make informed decisions, but in doing so, we are not aligning with either of these vociferous and deeply divided factions.
Here are a few of the questions raised by critics of our research:
Could some process other than UD be responsible for the abnormalities detected?
We have consistently considered other potential explanations for the results we have reported in this and related studies. Full consideration of this question is detailed in our article, but here is a brief explanation: The study area in question is in an extremely rural location. Agriculture is the primary activity, but it has been largely ruled out as a contributor because of the nature and levels of many of the compounds detected. This leaves primarily UD as the largest activity in the area, and the one activity that changed dramatically over the time period investigated. It is unlikely that other natural or anthropogenic processes could account for the substantial variations and abnormalities in groundwater quality we observed.
Why is there a lack of consistency or trends in detections from one phase of the study to the next?
One would not expect contamination events to be consistent and gradual, because inefficiencies and failures with the UD process do not likely occur at a uniform and linear rate. This lack of uniformity is coupled with the facts that chemicals used during drilling and stimulation all have variable half lives and that in situ microbial communities can use some of these compounds as a carbon source. Collectively, these factors make it highly unlikely that you would observe clear trends in detectable contamination events.
Our data illustrate large changes in pH, total organic carbon, and the levels of multiple volatile organic compounds only after the expansion of multiple unconventional oil wells in the area. A closer collaboration with industry in the future would allow us to better characterize which UD processes have contributed or might contribute to observed changes in groundwater quality. In such a way, contamination events could be reduced. Contamination events can also be quickly mitigated with effective remediation strategies.
Why is the sample set so small? Why weren’t reference samples taken? Does this study represent one with a true baseline?
We began monitoring groundwater quality at the earliest onset of UD possible to this point. Only one oil well had been established within a 5-km radius of the approximately 40 water wells we monitored. We clearly state in our recent article the difficulties associated with finding a study area where drilling has either not begun or is expected to expand, since the industry does not adequately publicize exactly when and where they are going to drill. Although our initial set of measurements does not constitute a perfect baseline, it does provide a reference of water quality before a large expansion of UD in the study area. It is as close to a baseline as anyone has ever been able to show. Water quality showed no exceedances of EPA maximum contaminant levels in the first phase of the study for the compounds we measured. That situation changed dramatically throughout the time course of the study.
In this type of research we rely on private landowners to allow us to sample their water. In this case, we were able to collect a coherent data set on a series of water wells over time. The number of water wells was sufficient for us to apply appropriate statistics and to assess significant versus insignificant changes over time. Obtaining reference samples from unaffected areas can be difficult because landowners may not see the value in having those samples taken if there is no potential threat from anthropogenic processes. Such reference samples may also be of questionable value because the geology of a study area may differ from that of the reference areas.
In the end, it is important to understand that compared to the magnitude of UD activity that has been performed by industry, the amount of research to assess its potential environmental impact has been miniscule. Can the process have a deleterious impact if not well managed? I think so. Can it be performed in a responsible manner? I think this is also possible, if best practices are implemented and followed. I wrote about this in an LCGC blog some time ago (6). What is unfortunate is that the most vocal proponents or opponents to UD fail to see a middle ground. Only through trusting in the scientific research performed by well-qualified teams of experts can the real answers be obtained.
1. Z.L. Hildenbrand, D.D. Carlton Jr., B.E. Fontenot, J.M. Meik, J. Walton, J.B. Thacker, S. Korlie, C.P. Shelor, A.F. Kadjo, A. Clark, S. Usenko, J. Hamilton, P. Mach, G. Verbeck IV, P. Hudak, and K.A. Schug, Sci. Tot. Environ.562, 906–913 (2016).
2. “UTA Research Demonstrates that Groundwater Quality Changes Alongside the Expansion of Hydraulic Fracturing and Horizontal Drilling,” University of Texas at Arlington News Center. April 26, 2016. http://www.uta.edu/news/releases/2016/04/Schug-permian-basin.php.
3. T. Burton, H. Rifai, Z.L. Hildenbrand, D.D. Carlton Jr., B.E. Fontenot, and K.A. Schug, Sci. Tot. Environ.545–546, 114–125 (2016).
4. Z.L. Hildenbrand, D.D. Carlton Jr., B.E. Fontenot, J.M. Meik, J. Walton, J.T. Taylor, J.B. Thacker, S. Korlie, C.P. Shelor, D. Henderson, A.F. Kadjo, C.E. Roelke, P. Hudak, T. Burton, H.S. Rifai, and K.A. Schug, Environ. Sci. Technol.49, 8254–8262 (2015).
5. B.E. Fontenot, L.R. Hunt, Z.L. Hildenbrand, D.D. Carlton Jr., H. Oka, J.L. Walton, D. Hopkins, A. Osorio, B. Bjorndal, Q. Hu, and K.A. Schug, Environ. Sci. Technol.47, 10032–10040 (2013).
6. K.A. Schug, “Responsible Unconventional Oil and Gas Exploration in Colombia,” The LCGC Blog, December 10, 2014. http://www.chromatographyonline.com/lcgc-blog-responsible-unconventional-oil-and-gas-exploration-colombia
Kevin A. Schug is a Full Professor and Shimadzu Distinguished Professor of Analytical Chemistry in the Department of Chemistry & Biochemistry at The University of Texas (UT) at Arlington. He joined the faculty at UT Arlington in 2005 after completing a Ph.D. in Chemistry at Virginia Tech under the direction of Prof. Harold M. McNair and a post-doctoral fellowship at the University of Vienna under Prof. Wolfgang Lindner. Research in the Schug group spans fundamental and applied areas of separation science and mass spectrometry. Schug was named the LCGCEmerging Leader in Chromatography in 2009 and the 2012 American Chemical Society Division of Analytical Chemistry Young Investigator in Separation Science. He is a fellow of both the U.T. Arlington and U.T. System-Wide Academies of Distinguished Teachers.