Water near fracking sites may be at risk: study

Households within a kilometre of fracking wells could be at higher risk of having their drinking water contaminated, research suggests.

A study of 141 drinking water samples from bore holes in Pennsylvania found higher levels of methane, ethane and propane in those close to shale gas fracking sites.

The gases were not found at concentrations that would affect health but the findings will add to concerns of critics that the process could have unforeseen consequences. It will also raise concerns about the risk of explosions if pockets of methane form in pipes.

British scientists said the findings should not halt at- tempts to begin fracking. But the research highlighted the need for careful monitoring of water around drilling sites.

Fracking or hydraulic fracturing involves extracting natural gas from underground shale wells by injecting water, sand and chemicals at high pressure, splintering the rock.

The study found that levels of methane were six times higher at homes within a kilometre of a shale gas well.

Ethane levels, though much lower than those of methane, were 23 times higher than usual in homes within a kilometre of drilling sites. Traces of propane were found in 10 homes, researchers reported in the Proceedings of the National Academy of Sciences journal.

Robert B. Jackson, a professor of environmental sciences who led the study, said the findings suggest drilling has affected water to some homes.

Studies in different shale formations have shown no signs of escaped gas, suggesting that leakages could only be a problem in certain areas.

Britain, which also uses bore holes as a source of drinking water in many areas, is thought to have rich reserves of shale gas. But the first attempt to extract it near Blackpool was temporarily halted after the process caused minor earth tremors. Stuart Haszeldine, professor of sedimentary geology at Edinburgh University, said the amounts of escaped gas were “undesirable, but not fatal.”

Future fracking attempts should be carefully analyzed, he said.

“This is a really strong piece of evidence,” he said. “We have to take this as evidence that groundwater monitoring is needed until we can understand what the particular shales in the U.K. would work. I see no reason to be alarmed, but I do see a reason to do more follow-up work.”