A recently-published study by researchers at the University of Texas at Arlington (UTA) finds high levels of arsenic and other heavy metals in aquifers overlying the Barnett Shale formation in northern Texas, near active natural gas wells. Researchers found that the chemical and metal levels exceeded the Environmental Protection Agency’s (EPA) maximum limits for drinking water standards in wells located within about two miles of fracking sites.
During the last ten years, the Barnett Shale formation has become one of the most heavily fracked shale formations in the United States. As of May 2013, the area contained about 16,743 active wells.
Lower levels of arsenic, selenium, strontium, and barium were found at sites outside the Barnett Shale region, as well as within the region located more than two miles from active natural gas wells. Methanol and ethanol were detected in 29 percent of sample, substances that do not naturally occur in groundwater, according to their findings.
Samples exceeding the EPA’s Maximum Contaminant Limit (MCL) were found throughout areas of active natural gas extraction, or fracking.
In an interview with ProPublica, the paper’s lead author, Brian Fontenot, discussed his team’s findings and why they are important. Fontenot, who works for the EPA in Dallas, teamed up with UTA researchers and private landowners to test water wells for various chemicals thought to be used in the hydraulic fracturing process.
“These heavy metals do naturally occur in the groundwater in this region. But we have a historical dataset that points to the fact that the levels we found are sort of unusual and not natural. These really high levels differ from what the groundwater used to be like before fracking came in,” he said in the interview.
While the study found that all water wells exceeding the MCL were found within about two miles of a natural gas well, not all samples close to natural gas wells had elevated contaminant levels. However, heavy metal levels decreased in water wells located farther away from natural gas wells.
The team compared data to a historical dataset from the same aquifers prior to natural gas activities. In one sample, the level of arsenic, a well-known poisonous chemical, detected was about 18 times higher than both the maximum concentration in reference area samples, or samples from areas without fracking, as well as historical levels for the region.
While much more research is needed on the impacts of fracking, this new study shows that water contamination issues occur geographically close to natural gas extraction sites.
At the end of last month, the Los Angeles Times released a report based on an internal EPA PowerPoint presentation, in which employees of EPA’s mid-Atlantic office in Philadelphia warned superiors that several wells in Dimock, Pennsylvania were contaminated. The EPA collected data from wells in Dimock over a period of 4 ½ years, after residents there complained of contaminated water.
Yet, after the EPA finished its investigation last year, it determined that for almost all of the 64 wells sampled, the water was safe to drink. Near the end of the investigation, staff at the EPA’s mid-Atlantic office urged the EPA to continue its assessment.
The EPA also released a draft report in 2011 of an investigation of water contamination in Wyoming, where residents have complained that fracking polluted their drinking water. The draft report stated that fracking was responsible for the pollution of an aquifer below Pavillion, Wyoming, an area that has been fracked extensively over the last two decades. The study was dropped by the EPA in June 2013.