Method of extracting natural gas may contaminate drinking water
Researchers at Duke University in the US state of North Carolina analysed 141 drinking water samples from private wells across the gas-rich Marcellus shale basin in the state of Pennsylvania. They found concentrations of methane were six times higher and ethane levels 23 times higher at homes within a kilometre of a shale gas well.
New evidence shows that fracking may contaminate drinking water, according to a study.
Propane was detected in 10 samples, all of them from homes within a kilometre of drilling.
"The methane, ethane and propane data, and new evidence from hydrocarbon and helium isotopes, all suggest that drilling has affected some homeowners' water," said study author Robert Jackson, an environmental sciences professor.
Two previous studies by Duke scientists found direct evidence of methane contamination in water wells near shale-gas drilling sites in northeast Pennsylvania. A third study conducted in Arkansas by US Geological Survey scientists found no evidence of drinking water contamination from shale gas production.
The ethane and propane contamination data was "new and hard to refute", Jackson said.