A new scientific study has, for the first time, found a pattern linking hydraulic fracturing and natural gas drilling with methane contamination of drinking water, with some contamination levels so high that faucet taps can be set on fire.
For the first time, new research conducted by four Duke University scientists shows that water supplies close to natural gas wells had an average of 17 times the level of flammable methane gas as wells further from active drilling operations.
The study, Methane Contamination of Drinking Water Accompanying Gas-well Drilling and Hydraulic Fracturing, documents “systematic evidence” of the connection between methane contamination in drinking water and shale-gas extraction.
A total of 68 wells were tested by the research team, all located in the Marcellus and Utica shale drilling areas, located in northeastern Pennsylvania and southern New York state. The group defined active gas extraction areas as within one kilometer (around six-tenths of a mile) of a gas well operation.
Robert Jackson, a biology professor at Duke and one of the report’s authors, said: “We certainly didn’t expect to see such a strong relationship between the concentration of methane in water and the nearest gas wells. That was a real surprise,” ProPublica reports.
Of the 68 wells, 60 were tested for dissolved gas concentrations. While dissolved methane in drinking water is currently not classified as an ingestive health hazard, it is an asphyxiant in closed spaces as well as an explosion and fire hazard.
Methane-contaminated drinking water has long been a complaint among people who live in the gas drilling and fracking areas of the country. ProPublica conducted an investigation in 2009 that revealed methane contamination as a result of gas drilling was widespread, including areas in Colorado, Ohio and Pennsylvania. It found that several homes blew up after gas had seeped into their water supplies or basements. A 2004 accident in Pennsylvania killed three people, among them a baby.
In Colorado, the investigation found at least a dozen cases where methane had entered drinking water supplies that were, according to residents, clean before fracking operations began nearby. In Dimock, Pa., the investigation discovered that some water wells exploded or the water could be lit on fire due to high levels of methane.
ProPublica reports the drilling industry and some state regulators claim these cases were either isolated problems or not related to drilling activities. However, the new research raises important questions as to how widespread methane contamination is and how unusual the trend is.
“It suggests that at least in the region we looked, this is a more general problem than people expected,” Jackson told ProPublica.
In addition to methane, the research detected other types of gases in the water, supplying additional evidence that the gases came from hydrocarbon deposits miles below the earth’s surface, and were unique to the active gas drilling areas.
Ethane and other hydrocarbons were detected in 81 percent of water wells near active gas drilling while just 9 percent of water wells outside the active drilling areas contained these gases. The research group believes leaky well casings were a likely cause of the contamination, but did not rule out underground migration. They also noted there were many older, uncased wells in these areas that had been abandoned.
The team also analyzed the water for signs of dangerous fluids that could have escaped from the gas wells and permeated the drinking water. They tested for radium, salts and other chemicals that would have signaled frack wastewater had made it into the aquifers. None of those types of fluids were found, but the group did not test for fracking chemicals or hydrocarbons like benzene. Instead, they relied on indicators such as saline or radioactive compounds.
Jackson told ProPublica he found it unlikely that toxic chemicals injected into the shale formations during the fracking process would enter water supplies in the same manner that methane did. “I’m not ready to use the word impossible, but unlikely,” he said.
The research team concluded that
greater stewardship, data, and - possibly - regulation are needed to ensure the sustainable future of shale-gas extraction to to improve public confidence in its use.