by Luke Jones
Posted 1/10/2013 09:54 am
Updated 11 months ago
A report from the United States Geological Survey stated that it did not find any groundwater contamination among 127 gas wells in the Fayetteville Shale.
According to a release, USGS scientists analyzed water quality from samples taken in Van Buren and Faulkner counties in 2011, focusing on chloride concentrations from 127 shallow domestic wells and methane concentrations and carbon isotope ratios from a subsample of 51 wells.
"None of the data that we have looked at as part of this study suggests that any groundwater contamination is resulting from natural gas production activities," USGS Hydrologist Tim Kresse said in the release. "However, this study does not speak to other wells that were not sampled, every chemical used during the hydraulic fracturing process or water quality changes that might take longer to occur. It does provide a baseline to use to evaluate any possible changes in the future."
A summary of the results from the study are as follows:
- Chloride concentrations were not higher in the 2011 samples than in samples from nearby areas collected from 1951 through 1983.
- Chloride concentrations from wells within two miles of a gas production well were similar to concentrations from wells more than two miles from a gas production well.
- Methane concentrations and carbon isotope ratios indicate that almost all methane in groundwater samples is naturally occurring as a result of biological processes in shallow shale formations used as a source of water for domestic purposes and did not originate from the Fayetteville Shale.