Wetland contamination can be predicted in oil boom states, study finds by Neela Banerjee, January 8, 2014, Los Angeles Times
WASHINGTON – Federal scientists have developed a system that could help prevent some contamination of wetlands and groundwater from oil development in the booming Williston Basin in Montana and North Dakota, according to a new study. Along with oil extracted from deep underground in the Williston Basin comes naturally occurring water called brine that is 10 times more saline than seawater and is dumped into reserve pits. Brine can contaminate local water sources through leaching from the pits, pipeline spills or accidents. At many area oil wells, 10 barrels of brine are produced for every barrel of oil, making brine disposal a significant issue as Williston Basin oil extraction flourishes.
U.S. Geological Survey scientists, in a study focused on Montana’s Sheridan County on the border with North Dakota, have developed criteria that can identify areas at the highest risk for brine contamination. In a study published in the journal Science of the Total Environment, they found that water samples from areas deemed at high risk of contamination had substantial brine concentrations. Similarly, the authors found areas at low risk of contamination yielded samples with lower or no brine concentrations. “In areas where we had a high vulnerability assessment, the criteria ended up predicting very well, and where we had a low assessment, we did very well,” said Todd M. Preston, the study’s lead author. The analysis could help landowners, regulators and oil industry officials in the Williston oil boom “quickly and easily identify areas with the greatest potential contamination” from brine, the study said.
Nationwide, disposal of the billions of gallons of wastewater generated daily from oil and gas drilling has vexed the industry, environmentalists and communities. … But as wells and waste storage pits proliferate, concern has grown about their effect on water. Last week, North Dakota officials were forced to halt a waste pit after the town of Ross, about an hour’s drive east of Williston, protested its proximity to their drinking water source.
… The new study, published online on Dec. 27, found that government officials work with oil companies to locate oil wells away from wetlands on public land. But most of the Williston Basin oil drilling is on private land and the study concluded oil wells “are often placed very close to wetlands to preserve farmable acreage,” increasing the risk of brine contamination. The study is the latest from a unit of the U.S. Geological Survey established in 2008 to monitor the environmental effects of energy development in the Prairie Pothole region, a vast swath of intermittent wetlands from Alberta, Canada, to northern Iowa. The region, which overlaps with the Williston Basin, is vital habitat to migratory North American waterfowl. Until the late 1970s, oil companies dumped brine into unlined pits, which have a history of causing contamination. Pits in the Williston Basin must be lined and then buried once reclamation begins. But no monitoring of possible leaching or contamination from the pits is required. “There are still uncontained releases of brine in the form of spills, pipeline breaks and vehicle accidents, which often occur closer to oil wells,” Preston said. Moreover, the open-air storage of brine still holds hazards, said independent scientists who read the USGS study. While lined pits are an improvement over unlined ones, liners also tear sometimes, as the experience with landfills has shown, said Geoffrey Thyne, principal scientist at Science Based Solutions, an environmental consulting firm in Wyoming. “It’s very difficult to maintain the perfect integrity of a liner,” he said. “It’s better than not being lined, but it’s not perfect, and we will continue to see issues with contamination.” [Emphasis added]
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