There are elevated levels of arsenic and other heavy metals close to natural gas sites in North Texas’ Barnett Shale area, UT-Arlington researchers announced last week.
The study did not conclusively link the heavy metal concentrations to fracking itself, claiming that they could be the product of lower water tables from drought, removal of water used for fracking, or faulty gas-well casings. The research was released in Environmental Science and Technology, a peer-reviewed journal.
“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 lead author Brian Fontenot.
Arsenic, barium, strontium, and selenium occur naturally at low levels in North Texas groundwater, but the study says fracking could elevate their levels. Elevated levels for most of the metals were not found outside active drilling areas or outside the Barnett Shale area.
Some wells were near to natural gas production sites; some were not. Although arsenic was found in 99 of the 100 wells, levels were “significantly higher in active [gas] extraction areas,” the study reads. Twenty-nine of the wells registered arsenic concentrations above levels that the EPA considers safe—.010 parts per million. One well near a natural gas site was “almost 18 times higher” than levels found in the Barnett Shale prior to the fracking boom.
The Environmental Protection Agency instituted arsenic-level restrictions in 2006, a move that protected an estimated 12 million Americans. Non-cancer effects can include thickening and discoloration of the skin, stomach pain, nausea, vomiting, diarrhea, partial paralysis, and blindness. Arsenic has been linked to cancer of the bladder, lungs, skin, kidney, nasal passages, liver, and prostate.
Samples were gathered from 100 private water wells of varying depths within a 13-county area in or near the Barnett Shale during four months in summer and fall of 2011. The samples were compared to historical data on water wells from the Texas Water Development Board groundwater database for 1989-1999, before natural gas drilling activity ramped up.
“Natural gas drilling is one of the most talked about issues in North Texas and throughout the country,” said UT-Arlington associate professor of chemistry and biochemistry Kevin Schug. “This study was an opportunity for us to use our knowledge of chemistry and statistical analysis to put people’s concerns to the test and find out whether they would be backed by scientific data.”