Environmental Cleanup at Navy Facilities Adaptive Site Management (2003) / Chapter Skim
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2. Adaptive Site Management
2. Adaptive Site Management
Pages 48-105
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From page 48... ...
and then introduces adaptive site management an approach that can address these problems while encompassing all stages of cleanup. Multiobjective Nature of Site Cleanup Contaminated sites can pose multiple hazards to human and ecological health, natural resources, and the economic and social welfare of surrounding communities.
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From page 49... ...
These objectives are usually pursued with different emphasis and urgency in different phases of a site cleanup effort. Following site discovery, the first priority is to eliminate immediate threats to human health and safety.
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From page 50... ...
Approaches that appear cost-effective because of lower capital and initial operating costs may in the long term be more costly, especially if unanticipated problems arise in remediation performance and/or site conditions. Better anticipation of such problems, both initially and through ongoing data collection and evaluation, and ensuring that flexibility is maintained for improving or changing remediation technologies when needed, are key elements of the adaptive site management approach proposed later in this chapter.
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From page 51... ...
, effective public participation and input into the planning of a site cleanup are both a means to ensure that the remediation plan can be implemented without costly delays and conflict and an end because public participation is a core value of a democratic society. Promoting participation and communication with the local community and other affected stakeholders applies to all aspects of a military site's operation, but it is especially important in dealing with health and safety risks to the public, where trust is easy to lose, but very difficult to regain (SIovic, 1993~.
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From page 52... ...
Our seventh objective of advancing knowledge during a site cleanup effort both knowledge of the site itself and broader insights applicable to other sites is usually secondary, and as a practical matter may be hard to justify to site managers and the public alike. However, because the science of cleaning up hazardous waste sites is often insufficient to attain even risk-based remediation goals, advancing scientific knowledge must be a component of site remediation.
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From page 53... ...
. To assist in this effort, two more specific site cleanup metrics, contaminant mass removal and risk reduction, are often used to define the specific operational objectives of a remediation program.
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From page 54... ...
This concern is especially important when considering large-scale excavation of contaminated soils or active dredging of sediments. Although risk reduction and mass removal are not the only targets for hazardous waste cleanup, they are common operational objectives; thus, their relationship is explored in greater detail.
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From page 55... ...
Adaptive Site Management 55 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: .........................................................
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From page 56... ...
shows the amount of exposure or potential risk for the same cleanup plan. M strategies emphasize contaminant mass removal, while E strategies focus on exposure and risk reduction.
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From page 57... ...
With this representation, the origin represents the starting point of site cleanup, when there is significant contaminant mass present at the site and affected populations are subject to significant exposure and potential risk. Progress in achieving cleanup and restoration is shown by moving along one of the paths over time toward the upper right-hand corner (i.e., total risk reduction and complete mass removal)
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From page 58... ...
M) / j / ~ / M2| Contaminant Mass Removal total onsite mass removal FIGURE 2-2 A multiobjective representation of alternative remediatior, and site management strategies in terms of contaminant mass removal and exposure or risk reduction.
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From page 59... ...
The following section describes conditions typically seen at complex hazardous waste sites in which the chosen remedy has been unsuccessful in meeting cleanup goals. Technica1/t Factors Influencing Remedy Electiveness Many methods for remediation of contaminated soil, sediments, and groundwater are characterized by an initial phase of relatively high effectiveness, followed by a prolonged period of much lower effectiveness.
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From page 60... ...
Both geological and flow heterogeneity (discussed below) can limit the effectiveness of many strategies for active remediation of soil and groundwater, such as pump-and-treat, soil vapor extraction, in sits chemical oxidation, and air sparging.
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From page 61... ...
Erosion-deposition processes in contaminated sediments. Natural attenuation processes in sediments may lead to decreases in water column contaminant concentrations over time.
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From page 62... ...
This value is generally above both screening levels and remedial goals frequently set for these compounds (EPA, 1997b; Buchman, 1999~. There are numerous case studies that document how the effectiveness of remediation decreases over time, one of which is highlighted in Box 2-3.
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From page 64... ...
The general trend is shown conceptually in Figure 2-4, which demonstrates how the effectV 1 Time of Remediation Time of Remediation FIGURE 2-4 Schematic graphs showing typical changes in cumulative mass removed and the mass removal rate over time. In cases where costs increase linearly with time, the x-axes may also represent cost.
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From page 65... ...
In many cases, treatment technologies reach an asymptote prior to reaching this goal, although protectiveness can often be maintained by cutting off exposure pathways via containment or institutional controls. Except for guidance on technical impracticability, there is minimal if any guidance on how to deal with situations in which cleanup goals are not being met after prolonged operation of the remedy (which necessarily prevents site closeout)
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From page 66... ...
(DoD, 1997~. This same guidance does not explicitly state whether failure to attain a health-based groundwater or soil remedial action goal constitutes a failure to "perform as expected." Thus, except for technical impracticability, there is no widely accepted policy for addressing situations where cleanup goals are not being met after extended operation of the remedy.
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From page 67... ...
Because of the complexity of the subsurface environment, often incomplete identification of contaminant sources, and the long timeframes required for remediation, site cleanup must not be viewed as a one-time event or an action that ends once a remedy is implemented. The need for iterative, adaptive approaches to site restoration and stewardship is supported by much of the recent literature on risk assessment and risk management.
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From page 70... ...
and by public participation (Shindler and Cheek, 1999~. The committee has coined the term "adaptive site management" (ASM)
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From page 71... ...
At its heart is a formal decision process that stresses the collection and evaluation of information on remedial performance, provides options in the face of uncertainty, and embeds linked feedback loops so that action is taken quickly to change or optimize remedies that are unlikely to attain sitespecific cleanup goals within a reasonable period of time. The main tenets of ASM are that it: · is applicable at various stages of site restoration, · is applicable to a wide variety of sites regardless of the contaminants being addressed or remedies envisioned, · provides a mechanism for the optimization of existing remedies, changing ineffective remedies, and refining the site conceptual model, · formalizes the routine examination of monitoring data and how to act upon the data, incorporates public participation, recognizes uncertainty and suggests approaches to dealing with it, especially when institutional controls are used, stimulates the search for new, innovative technologies to replace older or inefficient approaches.
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From page 72... ...
In particular, it noted the need for (1) a long-term monitoring program in the Grand Canyon and (2)
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From page 73... ...
Adaptive management has a similarly strong foundation in business strategies and planning approaches that utilize "feedback loops" to help respond to new information (Ayres, 1969~. Iterative programs with ongoing performance evaluation and improvement are also a key component in the recent design of corporate environmental management systems (Crognale, 1999~.
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From page 74... ...
Finally, federal site management cannot afford obvious failures in remediation. Every site is unique and important, and its aggregate management is expected to be successful.
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From page 75... ...
ASM builds on these experiences to provide a framework that weaves adaptability into the remedial design and implementation process as a whole. By explicitly recognizing the role of ongoing research and information collection, remedial performance assessment, and evaluation of alternative remedies, ASM provides greater flexibility than the current, more linear approach to site management, with the expectation of an
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From page 76... ...
implementing different remediation (including the sequencing of several remedial technologies to achieve cleanup goals) when the remedial action cannot be modified to achieve cleanup goals, or (3)
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From page 77... ...
The individual tasks of Step 1 include developing the problem/context and the site conceptual model and conducting risk assessments. It should be noted that there is nothing about the Step 1 process outlined in Figure 2-6 that is not already encompassed by the CERCLA cleanup paradigm.
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From page 78... ...
Data Inputs Contaminant levels, fate and effects in media (air, water, soils, sediments, groundwater) , and human and ecological receptors Site characterization: physical, chemical, and biological parameters FIGURE 2-6 Step 1 of adaptive site management: pre-remedy selection.
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From page 79... ...
Both active military bases and those that are closing are of substantial interest to the local public and, in some cases, to the larger public in a particular geographic region. thus, It IS Imperative that site managers identify individuals or groups that should be consulted on future land use issues and on the remedies being considered to achieve cleanup consistent with the planned land use.
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From page 80... ...
Data Inputs Although not a separate activity per se from problem/context formulation and site conceptual model development, data collection is nonetheless a key element of ASM. Quantitative data are needed to support remedy selection, to determine if the remedy is effective, and to reveal how the remedy should be implemented or modified to achieve optimal performance (NAVFAC, 2000, 2001~.
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From page 81... ...
Step 2 of ASM also links readily with the elements of Step 1 because it is expected that there will be situations where it will be necessary to return to Step 1 to refine the site conceptual model, collect additional information, refine the risk assessment, or change the remedial goal. A key element of ASM is the formalization of "management decision periods" (MDP)
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From page 82... ...
FIGURE 2-7 Step 2 of adaptive site management process: post-remedy selection. The shaded areas show the activities related to the management decision periods described in the text.
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From page 83... ...
At the onset of Step 2, a remedial goal is chosen that takes into consideration the risk assessment results, expected or desired future land use, public and stakeholder concerns, and technological capabilities. The goal can be established to protect human health, ecological receptors, or both, and will be site-specif~c.
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From page 84... ...
For any independent review to be successful, site managers and regulators must agree beforehand to abide by the results of the expert panel. In this way both groups gain the benefit of additional advice absent the potential bias that may occur were the review to be conducted by experts from one group or the other.
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From page 85... ...
The monitoring plan should be designed in light of the site conceptual model so that the data not only will illuminate the remedy's performance, but will also be valuable in refining the site conceptual model at later stages of site restoration. Developing a monitoring program will require that the site managers and regulators agree on the kinds of parameters to be monitored and how those parameters fit with the performance standards established in a ROD or other regulatory document.
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From page 86... ...
. If the remedy is not meeting performance standards, the RPM should initiate a thorough review of the remedy, the site conceptual model, and other relevant data to ascertain why.
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From page 87... ...
Remedial goals may be based on containment, as in preventing a groundwater plume from moving offsite, or they may be based on mass removal, as for many groundwater extraction and sediment and soil excavation remedies. If the remedy is not meeting the remedial goal, then site managers are faced with two important considerations discussed in MDP3: how the remedy can be modified, optimized, or changed to meet the performance standards, and whether the remedial goal is inappropriate and in need of change.
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From page 88... ...
After determining that the remedy is not meeting remedial goals, the RPM and remediation team, in coordination with regulatory agencies and interested stakeholders, should address whether the remedial goal is still appropriate. If it is not, the site managers would return to Step 1 of ASM.
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From page 89... ...
This situation may necessitate a change in the future land use, perhaps from residential use to commercial/industrial use, which may in turn require modifications to deeds or restrictions on current or future property access agreements. Because changing the remedial goal automatically leads site managers back to remedy selection (see Figure 2-7)
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From page 90... ...
Such plots can also make it clear when continued operation of the existing remedy may incur substantial per-unit costs with relatively little improvement in mass removal. In order for these plots to be useful, the remediation team and the regulatory agencies must agree on a unit cost for the continued operation of the remedial action at the site under investigation, above which the existing remedy is no longer considered a tenable option.
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From page 91... ...
However, in recognition of the many existing sites for which remedies have been ongoing for some time and for which no evaluation and experimentation were done, Figure 2-7 shows an upward arrow from "optimize, change, and add to remedy" to "evaluation and experimentation." This suggests that it can be useful to conduct the latter activities even after a chosen remedy has stalled in meeting cleanup goals. While evaluation and experimentation take place, the temporary inability to meet performance standards or other regulatory requirements should not be used as a basis for notices of deficiency or enforcement action.
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From page 92... ...
If the remedial goal was based solely on mass removal and the required mass was removed, then the RPM is no longer required to take additional action if long-term monitoring is not required and if residual contamination (if any) poses no risk to human health or the environment.
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From page 93... ...
For sites where there is still some ongoing remediation, such as passive technologies or monitored natural attenuation, contaminant concentrations may steadily decrease, albeit slowly. In these cases, the site manager should periodically ask whether there is still residual contamination present in amounts that preclude unrestricted use and thus pose a human or ecological health risk.
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From page 94... ...
However, throughout this report the term "site closeout" is used to mean that residual contamination has been removed to levels below that which allows for unrestricted use, which is consistent with the DoD usage of the term. More specifically, "site closeout" refers to the "point at which the DoD will no longer engage in active management or monitoring at an environmental restoration site, and no additional environmental restoration funds will be expended unless the need for additional remedial action is demonstrated." According to interagency guidance, "for practical purposes site closeout occurs when cleanup goals have been achieved that allow unrestricted use of the property (i.e., no further long-term monitoring, including institutional controls, is required)
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From page 95... ...
MDP3 draws upon monitoring data as well as information from evaluation and experimentation and stakeholder input to optimize, modify, or replace remedies or revise remedial goals. MDP4 provides the road map for long-term stewardship and site closure for sites where residual contamination remains in place.
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From page 96... ...
Because of the enormous variability in site conditions across Navy facilities, it is not appropriate for this report to suggest a distinct cost basis for assessing whether or not to use ASM for example, transactional costs should only represent a certain percentage of the total costsalthough this may be possible in the future following more in-depth analysis by the Navy. Nonetheless, it is anticipated that up-front cost increases associated with implementing ASM will be balanced by the benefits of evaluation and experimentation, which include optimization of remedies and more expeditious achievement of cleanup goals.
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From page 97... ...
Full-scale ASM that includes public participation during each decision period should be targeted to the more complex and highrisk sites where projected large costs are at stake. ASM is particularly appropriate for sites with multiple or recalcitrant contaminants and multiple stressors and heterogeneous hydrogeology because progress at such sites is likely to have stalled prior to reaching cleanup goals.
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From page 98... ...
98 Environmental Cleanup at Navy Facilities: Adaptive Site Management ........................................................
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From page 100... ...
1993. Performing ecological risk assessments.
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From page 101... ...
1997c. Ecological risk assessment guidance for Superfund: process for designing and conducting ecological risk assessments.
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From page 102... ...
2000. Environmental Protection Agency: use of precautionary assumptions in health risk assessments and benefits estimates.
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From page 103... ...
1993. Ecological assessment of hazardous waste sites.
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From page 104... ...
2001. Guidance for optimizing remedial action operation (RAO)
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From page 105... ...
The case of ecological risk assessment. Human and Ecological Risk Assessment 1~4~:395-406.
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