ANN ARBOR, MI, Sept. 26, 2013 -- On Thursday, Sept. 5, University of Michigan researchers released seven technical reports that together form the most comprehensive Michigan-focused resource on hydraulic fracturing.
The studies, totaling nearly 200 pages, examine a wide variety of environmental and ecological topics related to the use of hydraulic fracturing in Michigan, as well as six other areas including public health, geology and hydrogeology, technology, policy and law, economics, and public perceptions.
While considerable natural gas reserves are believed to exist in the state and high-volume hydraulic fracturing has the potential to help access them, possible impacts to the environment and to public health must be addressed, the U-M researchers concluded.
"There's a lot of interest in high-volume hydraulic fracturing, but there really isn't much activity at the moment in Michigan," said John Callewaert, project director and director of integrated assessment at U-M's Graham Sustainability Institute, which is overseeing the project. "That's why now is a good time to do this assessment."
The study concluded that potential impacts of hydraulic fracturing on the environment are significant and include increased erosion and sedimentation, increased risk of aquatic contamination from chemical spills or equipment runoff, habitat fragmentation and resulting impacts on aquatic and terrestrial organisms, loss of stream riparian zones, and reduction of surface waters available to plants and animals due to the lowering of groundwater levels.
The environment/ecology report notes that Michigan's dense, interconnected aquatic ecosystems (streams, rivers, lakes, and inland and coastal wetlands) and the groundwater aquifers to which they are linked are of particular concern. The connectivity between surface and groundwater bodies "can lead to impacts distant from, as well as close to, drilling sites," according to the report by G. Allen Burton, professor in the School of Natural Resources and Environment and director of the U-M Water Center, and Knute Nadelhoffer, professor of ecology and evolutionary biology and director of the U-M Biological Station.
Though groundwater contamination is often cited as a top concern, surface contamination from spills and improper disposal of waste fluids likely carries the greatest risk for harmful water-quality impacts, due to proximity to potable water resources, according to the geology/hydrogeology report written by Brian Ellis, assistant professor in the Department of Civil and Environmental Engineering.
Of the total volume of hydraulic fracturing fluids injected into a well, amounts varying from 10 percent to 70 percent may return to the surface as "flowback water" after the pressure is reduced and gas or oil begin to flow toward the wellhead. In Michigan high-volume hydraulically fractured wells, the average amount of flowback water returning to the surface is about 37 percent of injected volumes, according to the Ellis report.
The flowback water is highly saline and can contain elevated levels of heavy metals and naturally-occurring radioactive elements, in addition to methane and the original chemical additives in the fracturing fluids. In Michigan, common hydraulic fracturing fluid additives include ethylene glycol, hydrochloric acid, isopropyl alcohol, methanol and ammonium persulfate, according to the Ellis report.
"However, since in Michigan all flowback is disposed of by deep-well injection and it is not allowed to sit in open pits, the risk of this type of contamination will be lower than in other states without such disposal opportunities and regulations," Ellis wrote.
The greatest challenge, however, to understanding the potential public health risks of hydraulic fracturing in Michigan is the lack of state-specific data, according to Niladri Basu, author of the public health technical report and a former faculty member at the U-M School of Public Health. While thousands of hydraulically-fractured wells have been drilled in Michigan, the potential public health risks related to these facilities have been poorly documented, Basu wrote.
For example, while operators of high-volume fracking wells are required to disclose the contents of their hydraulic fracturing fluids, operators of the 12,000 or so low-volume wells in the state are not. "There needs to be much greater understanding of what chemicals are being used in every well, with information related to volumes, amounts, disposal plans, etc., made available," Basu wrote
Since the late 1940s, an estimated 12,000 gas and oil wells have been drilled in Michigan using hydraulic fracturing, without any reported contamination issues. Most of those wells have been relatively shallow vertical wells that each used about 50,000 gallons of water.
Recently, however, a small number of deep, directionally-drilled, high-volume hydraulically fractured wells have been completed in the northern part of the Lower Peninsula. Those wells sometimes use several million gallons of water, and one Michigan well required more than 20 million gallons.
The U-M hydraulic fracturing study is expected to cost at least $600,000 and is being funded by U-M through its Graham Sustainability Institute, Energy Institute and Risk Science Center. State regulators, oil and gas industry representatives, staffers from environmental nonprofits, and peer reviewers provided input to the technical reports, and more than 100 public comments were considered.
Click here to view the full report.