WaterWell water contaminants highest near natural gas drilling: study

A new study of 100 private water wells in and near the Barnett Shale showed elevated levels of potential contaminants such as arsenic and selenium closest to natural gas extraction sites, according to a team of researchers that was led by UT Arlington associate professor of chemistry and biochemistry Kevin Schug.

A University of Texas, Arlington release reports that the results of the North Texas well study were published online by the journal Environmental Science & Technology. The paper focuses on the presence of metals such as arsenic, barium, selenium, and strontium in water samples. Many of these heavy metals occur naturally at low levels in groundwater, but disturbances from natural gas extraction activities could cause them to occur at elevated levels.

“This study alone can’t conclusively identify the exact causes of elevated levels of contaminants in areas near natural gas drilling, but it does provide a powerful argument for continued research,” said Brian Fontenot, a UT Arlington graduate with a doctorate in quantitative biology and lead author on the new paper.

He added: “We expect this to be the first of multiple projects that will ultimately help the scientific community, the natural gas industry, and most importantly, the public, understand the effects of natural gas drilling on water quality.”

Researchers believe the increased presence of metals could be due to a variety of factors including: industrial accidents such as faulty gas well casings; mechanical vibrations from natural gas drilling activity disturbing particles in neglected water well equipment; or the lowering of water tables through drought or the removal of water used for the hydraulic fracturing process.  Any of these scenarios could release dangerous compounds into shallow groundwater.

Researchers gathered samples from private water wells of varying depth within a 13-county area in or near the Barnett Shale in North Texas over four months in the summer and fall of 2011.

Ninety-one samples were drawn from what they termed “active extraction areas,” or areas that had one or more gas wells within a five kilometer radius. Another nine samples were taken from sites either inside the Barnett Shale and more than fourteen kilometers from a natural gas drilling site, or from sites outside the Barnett Shale altogether. The locations of those sites were referred to as “non-active/reference areas” in the study.

The release notes that researchers accepted no outside funding to ensure the integrity of the study. They compared the samples to historical data on