25 September 2011

The Top-Down Risk of Hydrofracturing

Posted by John Freeland

ExxonMobile commercials fail to address flowback fluids.

ExxonMobile geologist Erik Oswald is becoming quite a media “star.” As a fellow geologist, I think this is great. Erik’s on-camara presence is warm, friendly, competent, and, most importantly, reassuring. I have no doubt that’s exactly how he is in real life.

What Erik describes in Exxon commercials with respect to 1.5 mile vertical distance and engineered borehole barriers between the gas formation and near-surface aquifers is true enough but I take serious issue with his following comment, which he makes in the commercial linked above:

“Most wells are over a mile and a half deep, so there’s a tremendous amount of protective rock between the fracking operation and the groundwater.”

The above statement implies that the threat of groundwater contamination comes from a mile and a half below, and that the well is effectively sealed to prevent upward migration of contaminants associated with the deep shale gas formation. However, in most cases of groundwater contamination, with some important exceptions, the aquifer is threatened from above, not from below.

Flowback and Brine Contamination

Hydrofracturing involves pumping millions of gallons of fluid comprised of water, sand, and chemicals down a hole under tremendous pressure. Before gas can come out of the well, most of the fluid flows back up to the surface as brine containing some other junk picked up from the shale, some of which is toxic. This fluid is then usually stored in ponds prior to disposal.

Earlier this year, Dr. Conrad Volz of the University of Pittsburgh gave this testimony to the U.S. Senate Committee on Environment and Public Works and its Subcommittee on Water and Wildlife, Joint Hearing “Natural Gas Drilling, Public Health and Environmental Impacts”, April 12, 2011. Dr. Volz described hazardous aspects of flowback water this way:

(The third problem is) the disposal of gas extraction flowback fluids, carrying a plethora of toxic elements and chemicals, in inefficient “brine” treatment facilities and Publicly Owned Treatment Works (POTW’s) [commonly called sewage treatment plants], which discharge effluent into surface water sources. Studies of the effluent from a commercial facility in Pennsylvania that treats fluids only from gas and oil operations shows discharge of 9 pollutants in excess of nationally recognized human and/or aquatic health standards into a
nearby stream. The contaminants include:

• Barium, found in effluent over 8 times its minimum risk level (MRL) in drinking water to children and 27 times its EPA consumption concentrations for fish and “fish plus water”.
• Stable Strontium, found in effluent 43.29, 51.68 and 97.90 times the drinking water MRL’s for intermediate exposures for adult men, adult women, and children, respectively. Strontium levels found in effluent were 29,811 times the reporting limit in the plants NPDES permit.
• Bromide, which forms mixed chloro-bromo byproducts in water treatment facilities that have been linked to cancer and other health problems were found in effluent at 10,688 times the levels generally found acceptable as a background in surface water.
• Benzene, a known carcinogen, is present in effluent water at over 2 times its drinking water standard, over 6 times its EPA consumption criteria, and 1.5 times the drinking water MRL for chronic exposure for children.
• 2-butoxyethanol (2-BE), a glycol ether and used as an antifoaming and anticorrosion agent in slick-water formulations for Marcellus Shale gas extraction was found in effluent water at 24.48, 29.21, and 55.14 times the drinking water MRL’s for intermediate exposure to adult males, adult females, and children, respectively –based on hepatic health effects.
• Chlorides, the concentration of chlorides in the effluent was 138 and 511 times the EPA maximum and continuous concentration criteria set for the health of aquatic organisms, respectively.

I don’t blame Erik Oswald for omitting the part about flowback water in his commercials. I put that on his employer, ExxonMobile. And, I’m not opposed to hydrofracturing to extract natural gas. In fact, I’m in favor of it as I previously wrote here, if it is done with adequate environmental regulations and enforcement.

Companies like ExxonMobile and others need to face the water supply and quality issues associated with hydrofracturing head-on.Pretending they don’t exist doesn’t serve their long-term interests or those of society. Solutions to the technical problems of hydrofracturing are achievable, as far as I can tell. Until we commit to truly “doing this right,” we won’t see the full benefits of developing this domestic energy resource.