Wastewater is produced during oil and gas production, from both conventional and non-conventional wells, including fracking. In the exploitation of the Marcellus shale formation for natural gas, some of the flowback water is derived from the fracking fluids used to release the gas at depth. Some is derived from the shale itself.
Flowback waters can be reused or gathered for treatment to remove contaminants. But, a recent study in western Pennsylvania finds that water treatment is insufficient—elevated levels of contamination are found downstream when the treated water is discharged to local streams.
Significantly, while barium and radium, two common constituents in flowback waters, are mostly removed by the treatment plants, the radium that remains in the effluent water is rapidly adsorbed by sediments, where high concentrations build up.
The authors found that radium in some sediments downstream of the treatment plant was 200x greater than in upstream samples and above the regulatory limit for radioactive waste disposal.
This study is the first to confirm what many have suspected—extraction of natural gas from the Marcellus shale by hydraulic fracking can result in contamination of local surface waters. Radium is, of course, radioactive and a source of radon gas—both of which are significant health hazards to humans and other forms of life.
Natural gas is an important fuel for our nation’s future and our response to climate change. But, it must be exploited in a manner which does not increase human health problems and environmental contamination. Let’s hope we can get both sides of this issue at the negotiating table to figure out what can be done.
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Photo, taken on June 17, 2013, courtesy of Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.