Hydraulic Fracturing Poses Substantial Water Pollution Risks, Analysts
Say
- Aug. 7, 2012
012 /PRNewswire-USNewswire/ — 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. That
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. The practice, 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 wastewater disposal.
“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. Other water 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. The 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
Reaven 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 authors.
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 Marcellus Shale.” 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 Reaven developed, the volume of contaminated wastewater “would equate
to several hours flow of the Hudson River or a few thousand Olympic-sized
swimming pools.” That 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.
Risk Analysis: An International Journal is published by the nonprofit
Society for Risk Analysis (SRA). SRA is a multidisciplinary, interdisciplinary,
scholarly, international society that provides an open forum for all those who
are interested in risk analysis. Risk analysis is broadly defined to include
risk assessment, risk characterization, risk communication, risk management, and
policy relating to risk, in the context of risks of concern to individuals, to
public and private sector organizations, and to society at a local, regional,
national, or global level. www.sra.org1
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