Nature looks at the odoriferous threat to our drinking water created by new methods of natural gas mining:
Injecting large quantities of water and other fluids to fracture deep rock formations to liberate the methane within — a practice called hydraulic fracturing, or fracking — has become economically viable only in the past decade or so. In that short time, it has gained popularity with natural-gas producers: in one county in Pennsylvania alone, approvals for fracking permits increased 27-fold between 2007 and 2009.
…[B]y 2035 fracking is projected to account for some 47% of US gas production.
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Robert Jackson, a biogeochemist at Duke University in Durham, North Carolina, and his colleagues measured the methane concentrations in 60 drinking-water wells in northeastern Pennsylvania and nearby areas of New York state. Dissolved methane concentrations in water from the 34 wells located more than 1 kilometre from fracking operations averaged about 1.1 milligrams of dissolved methane per litre. But in water taken from 26 wells within 1 km of one or more fracking operations, methane concentrations averaged 19.2 mg l–1. Isotopic analyses of the carbon in that methane shows that the gas has the same signature as that being recovered from deep underground by fracking operations.
Although methane concentrations in drinking water aren’t regulated, says Jackson, the gas readily comes out of solution and is an asphyxiation and explosion hazard.