Six private water wells located in Wise County and near active gas wells all contained methanol and other contaminants, including arsenic, according to a study released July 26 by researchers at the University of Texas at Arlington.
“These water wells were located between 215 to 610 meters from the nearest natural gas wells and could represent concurrent contamination of multiple private wells, although we cannot identify the contamination source using this data,” read the report.
The samples contained an average of 28 milligrams of methanol per liter.
“People have died as a result of drinking large amounts of methanol,” according to the U.S. Environmental Protection Agency (EPA). “Drinking smaller, non lethal amounts of methanol adversely affects the human nervous system. Effects range from headaches to un-coordination similar to that associated with drunkenness. Delayed effects such as severe abdominal, leg and back pain can follow the inebriation effects of methanol. Loss of vision and even blindness can also occur after exposure to amounts of methanol causing inebriation.”
The researchers also found levels of arsenic, selenium, strontium and total dissolved solids at some of the water wells that exceeded the EPA’s Drinking Water Maximum Contaminant Limit (MCL).
The study evaluated samples from 100 private water wells in 13 counties (six in Wise County) drawing water from the Trinity and Woodbine aquifers spread across the Barnett Shale. Some were just a couple hundred meters from natural gas wells while others were up to two kilometers away. Those closest to wells tended to have higher levels of the above contaminants.
The study found no evidence of the chemicals benzene, toluene and other compounds used in hydraulic fracturing. Ed Ireland, executive director of Barnett Shale Energy Education Council, said that is consistent with past studies that didn’t specifically find any evidence that hydraulic fracturing actually contaminated the drinking water supply.
But the UTA study was consistent with a Duke University study released in June that also found higher levels of contaminants in water wells close to gas wells in the Marcellus Shale.
The UTA study also looked at historical data taken from 1989 to 1999 before the Barnett Shale boom began. Levels for several contaminants had increased in most instances.
While arsenic naturally occurs in the Woodbine and Trinity aquifers, the concentrations had significantly increased compared to historical data and when water wells were located closer to gas wells. One sample was 16 times safe levels set by the EPA.
“Exposure to arsenic can cause many health problems,” according to the U.S. National Institute of Health. “Being exposed to low levels for a long time can change the color of your skin. It can cause corns and small warts. Exposure to high levels of arsenic can cause death.”
The study stops short of blaming hydraulic fracturing and natural well production as the cause of the higher levels of pollutants in water wells, though.
“This study 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 lead author on the paper.