is a type of water that naturally occurs in shale formations
and has been trapped in these formations for millions of years. This type of water cycles through the formation while a well is being operated and as such picks up some of the chemicals used in fracking and from the shale formation
. These chemicals include total dissolved solids (TDS), methane
, propane, ethane, Naturally Occurring Radioactive Materials
, barium, magnesium, iron and calcium.
An irrigation system that uses produced water.
A 2014 peer-reviewed study from Rice University evaluated produced water from three different shale formations, one in New Mexico, one in Texas and one in Pennsylvania. The study found "that while fracking-produced water shouldn't be allowed near drinking water, it's less toxic than similar waste from coal-bed methane mining." Additionally, the contents of the water differed greatly, depending on which formation it was from. The researchers identified 25 inorganic chemicals in the water, six of which were unsafe to drink, in the levels found in the samples. These chemicals included antimony, arsenic, barium, chromium, copper and mercury. Researchers were surprised when they did not find the carcinogenic chemical benzene in any of the samples.
Part of the fracking process involves the introduction of fracking fluid into a well. This fluid is composed of 90 percent water, 8 to 9 percent frac sand or proppant and 1 to 2 percent that "may contain salts, friction reducers, scale inhibitors, biocides, gelling agents, gel breakers and organic and inorganic acids." This frac fluid interacts with the water that has been trapped within these geological formations. It is this interaction that the study found created "potentially toxic chlorocarbons and organobromides." According to one of the authors of the study, Andrew Barron, the level of these chemicals was minimal and are "not a cause for panic." Barron did say that the presence of these chemicals should lead to a review of how fracking wastewater is treated. The study can be found here.
- ↑ The Institute for Energy & Environmental Research for Northeastern Pennsylvania, “What is flowback and how does it differ from produced water?” accessed January 27, 2014
- ↑ LMT Online, "Looking for water in the oil field," August 8, 2014
- ↑ 3.0 3.1 3.2 Inside Climate News, "Fracking's Wastewater, Poorly Understood, Is Analyzed for First Time," September 5, 2014
- ↑ 4.0 4.1 4.2 4.3 Rice University News and Media, "New solutions needed to recycle fracking water," August 28, 2014