By Tom Kenworthy
As shale gas has emerged as potentially significant source of fuel for this country, it has come under increased scrutiny. A NY Times series raised concerns about pollution of surface waters by the wastewater produced during drilling of natural gas wells using hydraulic fracturing. A recent study by Cornell University researchers called into question the conventional wisdom that gas is far better than coal in terms of its carbon pollution, in part because of concerns of methane leakage during and after fracking.
Now comes a new paper by Duke University researchers that documents “systematic evidence for methane contamination” of household drinking water wells by shale gas drilling in Pennsylvania and New York.
The study, which the authors said was the first scientific examination of water contamination near shale gas drilling operations, found that water supplies within one kilometer of drilling sites were contaminated by methane at 17 times the rate of those water wells farther from gas developments. Though the study did not include baseline data from before gas drilling began, the authors said the methane found in water wells was chemically similar to that found in deep shale gas formations. The study also made no link between the methane contamination and hydraulic fracturing, a widely used drilling technique that pumps large quanities of water mixed with sand and chemicals at high pressures to fracture gas-bearing rock formations deep underground. The contamination was more likely coming through well bores because of leaky casings, the authors wrote.
Industry groups were quick to denounce the study as based on limited data and no baseline comparisons.
As gas drilling has increased substantially in shale gas formations stretching from Texas to New York State, there have been numerous reports of methane intrusion into homes and household water supplies. Those have included widely distributed videos of homeowners lighting on fire water pouring from kitchen faucets.
Methane is the primary ingredient in natural gas, and is not regulated as a contaminant because, the authors report in an accompanying paper of research and policy recommendations, it is “not typically viewed as a health hazard.”
The Duke researchers called for a medical study of the health effects of methane in household drinking supplies, a federal research program to test industry’s claim that hydraulic fracturing deep underground can’t lead to methane contamination of shallow water wells, and baseline studies of water quality prior to natural gas drilling. They also endorsed the regulation of hydraulic fracturing under the Safe Drinking Water Act, which was barred by a 2005 energy law passed by Congress, and full public disclosure of the chemicals used in hydraulic fracturing.
– Tom Kenworthy is a Senior Fellow at the Center for American Progress.
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