Studies find methane in Pa. drinking water
KEVIN BEGOS, AP
PITTSBURGH
(AP) — New research in Pennsylvania demonstrates that it's hard to nail
down how often natural gas drilling is contaminating drinking water:
One study found high levels of
methane in some water wells within a half-mile of gas wells, while
another found some serious methane pollution occurring naturally, far
away from drilling.
The
findings represent a middle ground between critics of the drilling
technique known as hydraulic fracturing who claim it causes widespread
contamination, and an industry that suggests
they are rare or nonexistent.
The
contamination from drilling is "not an epidemic. It's a minority of
cases," said Rob Jackson, a Duke University researcher and co-author of
the study released Monday. But he added
the team found that serious contamination from bubbly methane is "much
more" prevalent in some water wells within 1 kilometer of gas drilling
sites.
Methane is an odorless gas that is not known to be toxic, but in high concentrations it can be explosive and deadly.
The
Duke paper, published in the Proceedings of the National Academy of
Sciences, is an expansion of a 2011 study that attracted widespread
attention for its finding that drilling was
polluting some water wells with methane. The new study includes results
from 141 northeastern Pennsylvania water wells. It found methane levels
were an average of six times higher in the water wells closer to
drilling sites, compared with those farther away.
Ethane, another component of natural gas, was 23 times higher in the
homes closer to drilling.
Some
of the methane was at dangerous levels. The study found 12 homes with
levels above the recommended federal limit of 28 milligrams per liter,
and 11 of those water wells were closer
to gas drilling sites. Jackson said the researchers believe that faulty
drilling can cause methane pollution, but that natural causes can, too.
Eighty percent of all the water wells they tested contained some level
of methane, including many with no nearby
drilling.
In
2011, Pennsylvania strengthened rules for the steel casing and cement
around the top of a gas well that are meant to protect water supplies
from contamination, but some older wells
weren't drilled to those standards.
There
was some good news, Jackson said: The Duke researchers haven't found
any evidence that chemicals from hydraulic fracturing, or fracking, have
contaminated water wells.
"We're not seeing the things that people are most afraid of," Jackson said, referring to the chemicals used in fracking.
The
research is important because gas drilling has recently boomed in large
parts of Pennsylvania, Ohio and West Virginia and is being closely
studied by officials in New York, where
there's a moratorium on hydraulic fracturing for gas.
To
get at the natural gas trapped deep underground, drillers crack open
rock with a high-pressure mix of water, fine sand and chemicals pumped
into wells. The industry has brought a windfall
of royalties and jobs to some communities, but also concerns about air
and water contamination.
The
situation is complicated because Pennsylvania has many layers of oil,
gas, and coal-bearing rock as well as natural faults. All those can
enable gas to seep naturally into water wells,
even in areas without drilling.
One researcher who now consults for oil and gas companies and other clients questioned some of the Duke findings.
Fred
Baldassare, who worked for the Pennsylvania Department of Environmental
Protection for 25 years, said the study doesn't present an accurate
picture of the whole state because the
Duke team went to areas where residents had complained about drilling
contamination, rather than doing a random sample. Baldassare runs a
research company called Eschelon Applied Geosciences.
Baldassare said that overall the Duke researchers "make a case for stray gas migration caused by gas well drilling activity."
The
second water study was published online last week by the U.S.
Geological Survey. It found that some Pennsylvania water wells in areas
with no nearby drilling are naturally contaminated
with high levels of methane. It also found that 85 percent of the
samples had radon levels higher than federal safe limits.
One
well sample, taken at a hunting club, had such high natural methane
levels, it could have been flammable, said hydrologist Ronald Sloto.
"They knew they had a major water quality problem, they didn't know what it was," Sloto said.
The
USGS took samples from 20 wells in Sullivan County, in northeastern
Pennsylvania, in order to establish a pre-drilling baseline for water
quality.
Sloto said his study and the Duke paper confirm that pre-drilling water testing is an absolute necessity for homeowners.
"Once
you have drilling you can't get a baseline, it's too late" to determine
if drilling caused water problems or if they were already there
naturally, Sloto said.
The Marcellus Shale Coalition, an industry group, had no direct comment on the Duke findings.
"Private
water well quality and construction, as well as methane migration, is a
longstanding public health issue in Pennsylvania, dating back decades,"
CEO Kathryn Klaber said in an
email.
(ah flammable drinking water, it doesn’t get any better that this)
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