Natural gas fracking does increase petroleum gases in the domestic water wells of nearby homes, according to a Duke University study of the Marcellus Shale published in the prestigious Proceedings of the National Academy of Sciences. This also increases its carbon footprint.
Led by Robert B. Jackson, the study found that drinking water wells within one kilometre of natural gas fracking wells (horizontal drilling / fracturing) were contaminated with stray petroleum gases including methane, ethane and propane, with methane concentrations an average of six times higher than those wells farther away. High levels of petroleum gases can cause domestic water to catch fire, and can be an explosion hazard. The researchers studied 141 drinking water wells, primarily in northeastern Pennsylvania. It is a followup to a similar 2011 study.
"The methane, ethane and propane data, and new evidence from hydrocarbon and helium content, all suggest that drilling has affected some homeowners' water," said Jackson, a professor of environmental sciences at Duke's Nicholas School of the Environment, in a statement. "In a minority of cases the gas even looks Marcellus-like, probably caused by poor well construction."
A similar pattern emerged for ethane, with concentrations of the gas found 23 times higher on average for homes less than one kilometre from a gas well. The researchers found propane in 10 of the 133 homes they studied for this gas, all close to a gas well.
"The ethane and propane are signatures of fracking," USA Today reports Jackson as saying.
"The new data reinforces our earlier observations that stray gases contaminate drinking water wells in some areas of the Marcellus shale," added Avner Vengosh, study co-author and professor of geochemistry and water quality at Duke's Nicholas School.
Prof. Jackson has for years called for better regulation of fracking to reduce its environment risks and carbon footprint. He says:
"We need to know how much methane leaks into the air during
the production and
distribution of natural gas. Work by my group, and many others, is examining this very
question. If more than 3 percent of the methane produced leaks into the atmosphere,
then natural gas probably isn't better than coal for greenhouse gas emissions."
Stray gases are only one of the potential environmental threats from fracking. The Obama Administration's Bureau of Land Management recently adopted the American Legislative Exchange Council (ALEC) model bill for disclosure of fracking chemical fluids used on public lands.
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