Hydraulic Fracturing Poses Substantial Water Pollution Risks,
8/6/2012 - Society for Risk Analysis (SRA) - Washington, D.C. – Risk
analysts have concluded that the disposal of contaminated wastewater
from hydraulic fracturing (or “fracking”) wells producing natural
gas in the intensively developed Marcellus Shale region poses a
substantial potential risk of river and other water pollution.
conclusion, the analysts say, calls for regulators and others to
consider additional mandatory steps to reduce the potential of
drinking water contamination from salts and naturally occurring
radioactive materials, such as uranium, radium and radon from the
rapidly expanding fracking industry.
The new findings and
recommendations come amid significant controversy over the benefits
and environmental risks associated with fracking.
which involves pumping fluids underground into shale formations to
release pockets of natural gas that are then pumped to the surface,
creates jobs and promotes energy independence but also produces a
substantial amount of wastewater.
In light of their review of multiple possible water pollution
scenarios, the authors say future research should focus mainly on
“Even in a best case scenario, an individual
well would potentially release at least 200 m3 of contaminated
fluids,” according to doctoral student Daniel Rozell, P.E., and Dr.
Sheldon Reaven, Associate Professor and Director of Energy and
Environmental Systems Concentration in the Department of Technology
and Society, Stony Brook University.
The scientists present their
findings in a paper titled “Water Pollution Risk Associated with
Natural Gas Extraction from the Marcellus Shale,” which appears in
the August 2012 issue of the journal Risk Analysis, published by the
Society for Risk Analysis.
Disposal of the large amounts of fracking well wastewater that is
expected to be generated in the Marcellus Shale region—which covers
approximately 124,000 square kilometers from New York to West
Virginia—presents risks from salts and radioactive materials that
are “several orders of magnitude larger” than for other potential
water pollution pathways examined in the new study.
pollution pathways studied include: a tanker truck spilling its
contents while transporting fluids used in the drilling process
going to or from a well site; a well casing failing and leaking
fluids to groundwater; fracturing fluids traveling through
underground fractures into drinking water; and drilling site spills
at the surface caused by improper handling of fluids or leaks from
storage tanks and retention ponds.
The disposal of used hydraulic
fracturing fluids through industrial wastewater treatment facilities
can lead to elevated pollution levels in rivers and streams because
many treatment facilities “are not designed to handle hydraulic
fracturing wastewater containing high concentrations of salts or
radioactivity two or three orders of magnitude in excess of federal
drinking water standards,” according to the researchers.
wastewater disposal risks dwarf the other water risks, although the
authors say “a rare, but serious retention pond failure could
generate a very large contaminated water discharge to local waters.”
In trying to understand the likelihood and consequences of water
contamination in the Marcellus Shale region from fracking
operations, Rozell and Reavan use an analytical approach called
“probability bounds analysis” that is suitable “when data are sparse
and parameters highly uncertain.”
The analysis delineates best
case/worse case scenarios that risk managers can use “to determine
if a desirable or undesirable outcome resulting from a decision is
even possible,” and to assess “whether the current state of
knowledge is appropriate for making a decision,” according to the
The authors note that “any drilling or fracturing fluid is suspect
for the purposes of this study” because “even a benign hydraulic
fracturing fluid is contaminated once it comes into contact with the
Sodium, chloride, bromide, arsenic, barium and
naturally occurring radioactive materials are the kinds of
contaminants that occur in fracking well wastewater.
If only 10 percent of the Marcellus Shale region was developed, that
could equate to 40,000 wells.
Under the best-case median risk
calculation that Rozell and Reavan developed, the volume of
contaminated wastewater “would equate to several hours flow of the
Hudson River or a few thousand Olympic-sized swimming pools.”
represents a “potential substantial risk” that suggests additional
steps should be taken to lower the potential for contaminated fracking fluid release, the authors say.
Specifically, they suggest
that “regulators should explore the option of mandating alternative
fracturing procedures and methods to reduce the wastewater usage and
contamination from shale gas extraction in the Marcellus Shale.”
These would include various alternatives such as nitrogen-based or
liquefied petroleum gas fracturing methods that would substantially
reduce the amount of wastewater generated.
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interview with the author(s).
The complete study is available: