USGS's Shallow Groundwater Study Cuts Deep Into Argument that Fracking Degrades Water Quality
A new study by the U.S. Geological Service (“USGS”), released January 9, 2013, is another coup for industry in the science battle raging over hydraulic fracturing and its impacts on groundwater quality. The USGS, working with local regulatory agencies, sampled 127 domestic water wells in north-central Arkansas’ gas-producing area. Across the board, the study’s results support what industry has been saying all along – that fracking is safe and does not lead to drinking water contamination.
The purpose of the study was to sample groundwater from domestic wells, document groundwater quality and geochemistry, and investigate potential impacts to groundwater quality from gas-production activities in the region. USGS compared the 127 samples taken with historical data from the pre-drilling era (i.e., 1951-1983) for major ions, trace metals, methane gas, and any constituents that might have been added to fracturing fluids for gas drilling. It also conducted a spatial analysis, comparing the samples to those taken more than two miles from gas-production activities.
The study focused on the constituent chloride because it would be the first to break through the separation zone and into drinking water supplies if a contamination plume from gas-production water existed. The study found that chloride concentrations were below that of historical concentrations and, more importantly, that chloride concentrations for wells less than 2 miles from gas-production wells were not significantly different from those more than 2 miles from gas-productions wells. The spatial and temporal analyses confirmed that there was no evidence of migration of gas-production water into shallow groundwater, even with a separation distance between shallow groundwater and the gas producing zone of only 1,000-6,000 feet. Groundwater-quality data further indicated that groundwater chemistry in the shallow aquifer system is a result of natural, not anthropogenic, processes.
The USGS also analyzed methane concentrations and discerned whether it was attributable to natural or anthropogenic causes. Of the 51 samples analyzed for methane, those with concentrations above the detection limit were found to be likely biogenic in origin, meaning they derived from natural geochemical processes. Of the low concentration methane samples that were found to have a thermogenic signature, which ordinarily indicates that they most likely derive from anthropogenic releases, the USGS found evidence to the contrary. The study concluded that they too occur naturally in the study area and are not attributable to hydraulic fracturing activities.
While opponents of the oil and gas industry have pushed for scientific studies proving that hydraulic fracturing threatens drinking water resources, the USGS study echoes a recently leaked analysis from New York State’s Health Department, which concluded that fracking could be done safely. These types of findings, supported by rigorous science, provide the industry with the means to make their strongest case.