Increased Mud Found Downstream from Marcellus Drilling
12 March 2013
By Ken Ward Jr.
CHARLESTON, W.Va. -- Researchers have begun to identify ways that
wastewater and runoff from the natural gas production boom in the
Marcellus Shale region is making its way into area rivers and
A new study released this week documents increases in mud and silt
downstream from gas drilling and production operations and higher
levels of another key pollutant downstream from water treatment
plants that handle Marcellus wastes.
The study, published in the Proceedings of the National Academy of
Sciences, compared the results of more than 20,000 surface water
monitoring reports with the locations of 5,000 wells across the
gas-producing areas of Pennsylvania.
Researchers found a 10 percent increase in chlorides
concentrations for every 1.5 wastewater treatment facilities
located upstream. They found a 5 percent increase in total
suspended solids for every additional 18 well pads upstream.
"These are not dramatic changes that they found, but they're not
inconsequential either," said Duke University biologist Robert
Jackson, who has studied gas-production impacts, but was not
involved in the new research.
The study did not look at potential impacts on groundwater
supplies -- a matter of much public concern and scientific debate.
And it did not look for increases in any other toxic chemicals
that might be discharged from gas production. But the study did
confirm some previous findings about the drilling boom's effects
on streams and rivers.
"The nature of surface water contamination from shale gas
development considered here is qualitatively different from the
groundwater concerns explored in the literature," says the study,
written by Sheila Olmstead and others from the Washington, D.C.,
think tank Resources for the Future. "Although groundwater
concerns may have primarily to do with contamination directly from
wellbores or shale formations, surface water concerns may have
primarily to do with off-site waste treatment and above-ground
The study concluded, "These results can inform future voluntary
measures taken by shale-gas operators and policy approaches taken
by regulators to protect surface water quality as the scale of
this economically important activity increases."
Olmstead said that researchers found a statistically significant
increase in solids pollution downstream as the number of well
sites increased, but were not able to pinpoint which part of the
gas-production process caused the pollution. Testing did not
support their hypothesis that runoff impacts would be greater
during heavy rain events or during the construction of well pads,
or both, she said.
"So it may be that we are picking up on other aspects of
infrastructure development (pipelines, roads), which are
correlated with well pad construction," Olmstead said in an email.
"But lacking data on these other types of infrastructure, we don't
test that directly. So the question remains an open one."
Jackson said the large scope of the study -- looking at drilling
impacts across the state -- provided important broad-brush
information, but also did not allow for a closer look at
Brian Lutz, a Kent State University scientist who has also studied
gas-drilling impacts, said the scope of the study was such that it
didn't answer how pollution might impact different types of
"An 11 percent increase in chlorides in a pristine headwater
stream might have quite an impact, but an 11 percent increase in
chlorides in a major, developed river might not," Lutz said.
Reach Ken Ward Jr. at kw...@wvgazette.com or 304-348-1702.