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Cleanup of contaminated sites could take decades

November 13, 2012  By administrator

Nov. 13, 2012, Washington – A new report from the National Research Council says at least 126,000 sites across the U.S. have contaminated
ground water that requires remediation, and about 10 per cent of these
sites are considered complex.

Nov. 13, 2012, Washington – At least 126,000 sites across the U.S. have contaminated
ground water that requires remediation, and about 10 per cent of these
sites are considered "complex," meaning restoration is unlikely to be
achieved in the next 50 to 100 years due to technological limitations,
says a new report from the National Research Council. The report adds
that the estimated cost of complete cleanup at these sites ranges from
$110 billion to $127 billion, but the figures for both the number of
sites and costs are likely underestimates.

Several national and state ground water cleanup programs developed
over the last three decades under various federal and state agencies aim
to mitigate the human health and ecological risks posed by underground
contamination. These programs include cleanup at Superfund sites;
facilities that treat, store, and dispose of hazardous wastes; leaking
underground storage tanks; and federal facilities, such as military
installations. The U.S. Department of Defense (DOD) has already spent
approximately $30 billion in hazardous waste remediation to address past
legacies of its industrial operations. DOD sites represent
approximately 3.4 per cent of the total active remediation sites, but
many of these sites present the greatest technical challenges to
restoration with very high costs. Therefore, the agency asked the
National Research Council to examine the future of ground water
remediation efforts and the challenges facing the U.S. Army and other
responsible agencies as they pursue site closures.


"The complete removal of contaminants from ground water at possibly
thousands of complex sites in the U.S. is unlikely, and no technology
innovations appear in the near time horizon that could overcome the
challenges of restoring contaminated ground water to drinking water
standards," said Michael Kavanaugh, chair of the committee that wrote
the report and a principal with Geosyntec Consultants, Inc. in Oakland,
Calif. "At many of these complex sites, a point of diminishing returns
will often occur as contaminants in ground water remain stalled at levels
above drinking water standards despite continued active remedial
efforts. We are recommending a formal evaluation be made at the
appropriate time in the life cycle of a site to decide whether to
transition the sites to active or passive long-term management."

The estimated range of remediation costs do not account for
technical barriers to complete cleanup at complex sites or the costs of
cleanup at future sites where ground water may become contaminated, the
committee said. A substantial portion of the costs will come from
public sources as some of complex sites are "orphan" sites and many
other complex sites are the responsibility of federal or state agencies.

The committee said that the nomenclature for the phases of site
cleanup and cleanup progress are inconsistent among public and private
sector organizations, which could confuse the public and other
stakeholders about the concept of "site closure." For example, many
sites thought of as "closed" and considered "successes" still have
contamination and will require continued oversight and funding over
extended timeframes in order to maintain protectiveness, including 50
per cent of the contaminated ground water sites evaluated by the committee
that have been deleted from the Superfund list. More consistent and
transparent terminology that simply and clearly explains the different
stages of cleanup and progress would improve communication with the

"The central theme of this report is how the nation should deal with
those sites where residual contamination will remain above levels
needed to achieve restoration," Kavanaugh stated. "In the opinion of
the committee, this finding needs to inform decision making at these
complex sites, including a more comprehensive use of risk assessment
methods, and support for a national research and development program
that leads to innovative tools to ensure protectiveness where residual
contamination persists. In all cases, the final end state of these
sites has to be protective of human health and the environment
consistent with the existing legal framework, but a more rapid
transition will reduce life-cycle costs. Some residual contamination
will persist at these sites and future national strategies need to
account for this fact."

The committee said that if a remedy at a site reaches a point where
continuing expenditures bring little or no reduction of risk prior to
attaining drinking water standards, a reevaluation of the future
approach to cleaning up the site, called a transition assessment, should
occur. The committee concluded that cost savings are anticipated from
timelier implementation of the transition assessment process but funding
will still be needed to maintain long-term management at these complex

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