Study finds methane in wells near natural gas drilling

A controversial form of drilling for natural gas from shale rock appears to be contaminating groundwater wells with methane in northeastern Pennsylvania and Upstate New York, according to a Duke University study.

Researchers tested 60 wells last year for methane and found that 13 of the 26 wells within a kilometer of "hydrofracking" sites had elevated methane levels, some to the point where the water could catch fire.

Such levels were found in only one of the 34 wells beyond a kilometer of such drilling, according to study co-author Robert Jackson.

"I was extremely surprised. We did not expect to find so many houses with high methane concentrations near gas wells," said Jackson, an environmental science professor at Duke University. "It's pretty hard to explain away."

Hydraulic fracturing, or fracking, has come under increasing scrutiny as drilling intensifies in shale regions of the USA, especially the Barnett area in Texas, the Marcellus area in Pennsylvania and the Utica area in New York. This drilling method blasts waters, mixed with sand and chemicals, deep underground to fracture shale formation and allow natural gas to escape. Some of the liquid comes back to the surface.

Shale gas accounts for about 15% of natural gas produced nationwide, but the Energy Information Administration estimates it could account for half by 2035. The Environmental Protection Agency is also doing a major study on fracking.

Hydraulic Fracturing Source: USA TODAY Research By Frank Pompa, USA TODAY

The study, published online in the early edition of the Proceedings of the National Academy of Sciences, found measurable amounts of methane in 51 or 85% of the wells, but in those closest to fracking, the levels were 17 times higher on average.

The drilling industry criticized the research. "What you have here is a paper that draws pretty firm conclusions without much data at all to back any of them up. In fact, the authors admit they have no baseline data at all, which makes it impossible to characterize the state of those water wells prior to recent development," said a statement by Chris Tucker, spokesman for Energy In Depth, a Washington-based coalition of oil and natural gas producers.

Jackson said the researchers now have baseline data for many wells and will do follow-up testing.

They found no evidence of contamination from the chemicals used in fracking fluids or from the wastewater after the shale's been fractured.

Reports of such contamination prompted EPA Administrator Lisa Jackson in March to order testing for radioactivity at water treatment plants that receive the wastewater and intake sites for public drinking water downstream from the plants.

The Duke scientists recommend doctors study the health effects of chronic low levels of methane, saying there is little research and the EPA does not regulate methane in drinking water.