What happens to hydraulic fracturing wastewater on cropland

This spring, the U.S. Energy Information Administration estimated that hydraulic fracturing accounts for two-thirds of the country's natural gas production. Customers have benefited from lower gas bills, but the technique's growth comes with some risks. The Colorado Oil and Gas Conservation Commission received reports of 838 spills that released a total of more than 660,000 gallons of fluids associated with fracking in 2014. Since hydraulic fracturing and, potentially, any associated spills often occur near agricultural land, Jens Blotevogel, Thomas Borch and colleagues wanted to find out whether compounds in the wastewater biodegrade or stick around in the soil where they might be taken up by crops.

The researchers tested the fates of three common hydraulic fracturing additives in agricultural topsoil. The surfactant polyethylene glycol completely degraded within 42 to 71 days. But the surfactant did not break down when combined with another hydraulic fracturing additive called a biocide at a salt concentration typical for wastewater produced during oil and gas extraction. The researchers say their findings highlight the need for further testing to better understand spills' potential effects on crops and the environment.