Please excuse the
On Wednesday, December
12, 2012, at 1:00 pm EST, the National Research Council (NRC) will host a free
Webinar explaining its new report, "Alternatives for Managing the Nation's
Complex Contaminated Groundwater Sites." Michael Kavanaugh, chair of the
report-authoring committee will present the report’s findings and, along with
other committee members (including myself), answer questions from the public.
Please register in advance for the webinar at: https://nasevents.webex.com/nasevents/onstage/g.php?t=a&d=665634292.
You may need to copy and paste the link.
News coverage about the
report has emphasized its conclusion that "The complete removal of
contaminants from groundwater at possibly thousands of complex sites in the
U.S. is unlikely." That's nothing new. The NRC has concluded that several
Some people, who appear not to have read the entire report, seem
to see it as justification for the wholesale shutdown of cleanup activity at
complex groundwater sites. It isn't.
Instead the NRC Committee has established a framework to help
make decisions about when it is appropriate to transition to passive long-term
management, and what that management entails.
The heart of the report, in my opinion, is its final chapter,
Chapter 7. Here are its conclusions and recommendations.
CONCLUSIONS AND RECOMMENDATIONS
many complex sites, contaminant concentrations in the plume remain stalled at
levels above cleanup goals despite continued operation of remedial systems. At
such sites, which may number in the tens of thousands, there is no clear path
forward to a final end state, such that money continues to be spent with no concomitant
reduction in the risks posed by the sites. If the effectiveness of
site remediation reaches a point of diminishing returns prior to reaching
cleanup goals and optimization has been exhausted, the transition to MNA or
some other active or passive management should be considered using a formal
transition assessment, which is akin to a focused feasibility study, would
determine whether a new remedy is warranted at the site or whether long-term
management is appropriate (see Figure 7-2). This analysis, particularly the
graphical demonstration that contaminant concentrations at a site have reached
an asymptote, is likely to enhance public involvement in long-term decision-
making and thus strengthen public confidence in the decisions made.
part of the transition assessment, the costs of remedial options should be
updated, ideally using probabilistic methods, to reflect the current present
value of costs in order to more effectively compare the costs of various future
alternatives. To the extent possible, the marginal cost of remediation
through time should be quantified. Also as part of the transition assessment,
formal post-remedy risk assessment should be conducted to compare alternatives,
including long-term active or passive management. This risk analysis should
explicitly consider uncertainty and take into account both individual and
population risks, where appropriate, such that the relative risk reduction of
the alternatives can be determined.
reviews are an extremely valuable source of field data for evaluating the
performance of remedial strategies that have been implemented at CERCLA
facilities and could be improved. To increase transparency and allow EPA, the
public, and other researchers to assess lessons learned, more should be done,
on a national basis, to analyze the results of five- year reviews in order to
evaluate the current performance of implemented technologies. EPA’s
technical guidance for five-year reviews should be updated to provide a uniform
protocol for analyzing the data collected during the reviews, reporting their
results, and improving their quality.
public involvement characterized by two-way communications and that builds
trust is a key element of good remedial decision-making, particularly at
complex sites. Federal agencies generally go beyond the minimum level of public
involvement by forming or recognizing advisory groups and providing technical
assistance, such that members of affected communities have the opportunity to
influence remedial decision-making. Nonetheless, public involvement
tends to diminish once remedies at a site or facility are in place. No agency
has a clear policy for sustaining public involvement during long-term
and federal responsible parties should work with members of existing advisory
groups and technical assistance recipients to devise models for ongoing public
oversight once remedies are in place. Such mechanisms may include annual
meetings, Internet communications, or the shifting of the locus of public
involvement to permanent local institutions such as public health departments.
Such involvement is critical to the success of the processes found in Figure
The cost of new remedial actions may decrease at
complex sites if more of them undergo a transition to passive long-term
management. However, long-term management at complex sites will still demand
substantial long-term funding obligations. Failure to fund adequately the long-term
management of complex sites may result in unacceptable risks to the public due
to unintended exposure to site contaminants.