Environmental Cleanup at Navy Facilities Adaptive Site Management (2003) / Chapter Skim
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3. Monitoring and Data Analysis to Support Adaptive Site Management
3. Monitoring and Data Analysis to Support Adaptive Site Management
Pages 106-163
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From page 106... ...
Monitoring programs supply the information required to support the four management decision periods (MDP) described in Chapter 2.
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From page 107... ...
advocates preparation of performance plots of monthly operation and cost data similar to Figure 3-1. Although mass removal is one objective measure of the remediation performance, cleanup goals are normally based upon reduction of total pollutant concentrations to health-based standards.
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From page 108... ...
over time. This second measure is more reliable, because calculation of the baseline risk associated with the initial contaminant level is fraught with uncertainty, whereas there is less uncertainty about the risk reduction (as measured by the surrogate concentration reduction)
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From page 109... ...
Ideally, there would be a set of performance curves like those in Figures 3-1 and 3-2 for different remediation methods or management options such that the curves could guide decisions as to which option to select and when to change from one approach to another. As an illustration of such curves, consider Figure 3-3, which shows a family of hypothetical curves for the risk reduction over time for various types of remediation systems.
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From page 110... ...
C, and E could represent any number of strategies where risk is reduced incrementally over time from the source zone, including monitored natural attenuation. Curve F may represent a strategy like containment or a landfill cap where no contaminant mass is reduced, with the dotted line representing the possibility of future catastrophic failure.
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From page 111... ...
. In addition to the qualitative assessments of the various curves described above, graphical tools could provide more quantitative guidance, assuming that reliable and accurate values for cost and risk reduction can be measured.
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From page 112... ...
with site-specif~c data to generate performance curves applicable to a specific site. Developing the models in the first place will require data collection at sites where remedies are already in place, including data on contaminant concentrations at compliance or receptor locations if risk reduction is a desired metric.
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From page 113... ...
, graphical analysis of monitoring data can enable identification of asymptotic conditions where concentrations are not low enough at the site to achieve the health-based remedial goal, and operation and maintenance costs have become high enough to raise concerns. Interpretation of the graphs to provide yes or no answers to these questions will be subjective, because there will likely be disagreement about various critical performance criteria (e.g., at what dollar value does the cost per pound removed become cost-inefficient, or at what slope of the concentration versus time curve should the remedy be changed)
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From page 114... ...
. At Pope Air Force Base, as much as 75,000 gallons of JP-4 free product are floating on top of the water table; some dissolved volatile organic compounds (VOCs)
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From page 115... ...
_ $0 o ~cL] mulatlvO arm n~cov~reu `=a~lon8, FIGURE 3-6 Free product removal versus cumulative operation and maintenance costs at Pope AFB.
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From page 116... ...
Initial remedial actions at the site were excavation of contaminated soil and removal of measurable free product. A groundwater pump-and-treat system began operation in July 1996; the system includes interceptor trenches and several extraction wells that were installed in plume hot spots.
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From page 117... ...
~ .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- ................................................................................................................................................ 117 .~ hi Hi FIGURE 3-7 Cumulative mass recovered versus time for the pump-andtreat system at the Campbell Street Fuel Farm.
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From page 118... ...
In order for this to occur, the slope of the line tangent to the concentration versus time curve must be approaching zero (the so-called asymptote) , yet the concentration must remain above the site-specific remedial action goal.
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From page 119... ...
When cost and concentration data analyses reveal declines in remedy performance prior to reaching the cleanup goal, the responsible party should undertake reconsideration of the remedy with the same public participation steps that are utilized in the original remedy selection process. In order for these exercises to be effective, the Navy, in consultation with stakeholders, should select 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 120... ...
Because of these uncertainties, it is not possible to assign a single value to either the baseline risk, or to the risk reduction that could be achieved by a given remediation technology. The extent of uncertainty about site conditions and remedial performance has implications for decision making throughout ASM.
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From page 121... ...
There, Me denotes the unknown total contaminant mass in the system, and the double-headed arrow is meant to convey uncertainty in that value. (Note that there could also be uncertainty in the asymptotic value of the cumulative mass removed.)
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From page 122... ...
That is, there is a 95 percent probability that the risk reduction is less than the upper curve, a 5 percent probability that the risk reduction is less than the lower curve, and thus a 90 percent probability that the risk reduction is between the upper and lower curves. The solid center curve might represent the mean or "best estimate." The figures discussed above are for treatment-based remediation strategies where there is a direct correlation between performance and time.
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From page 123... ...
The upper and lower curves correspond to the 5 and 95 percent probability levels. 1 00% ~ .m · - - , o o au cat ~ 0 au o F ailu're tim e ~ uncertainty ' P
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From page 124... ...
Their results do show that remediation reduces risk but, interestingly, there are differing amounts of risk reduction to different segments of the population. Their results are presented in the form of Figure 3-11, with confidence bands added to reflect fate-and-transport uncertainty.
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From page 125... ...
The method is demonstrated using an example of contaminated sediment disposal at Elliott Bay, near Seattle, where the possible remedial alternatives are (1) unconfined aquatic disposal (UAD)
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From page 126... ...
For each alternative, the outer box denotes the range of plausible values, while the inner hatched box denotes the range of most likely values. UAD = unconfined aquatic disposal, CAD = capped aquatic disposal, CDF = near-shore confined disposal facility, UPL = upland disposal, and UPS = upland secure disposal.
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From page 127... ...
A cursory examination of Figure 2-7 might suggest that monitoring is needed only to answer the three questions posed during MDP2. However, monitoring programs are essential to facilitate site characterization and risk assessment (Step 1)
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From page 128... ...
In the case of groundwater, most sites begin with an inherited set of monitoring points already established, and so part of the monitoring design process also includes determining to what extent this existing network can be used or must be abandoned or expanded. Depending on the chosen remedial actions, monitoring programs may represent the majority of remedial action costs (such as for monitored natural attenuation)
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From page 129... ...
Monitored Performance Parameters The performance evaluation graphs presented earlier focus on several key parameters measured over time. These include risk and risk reduction, contaminant concentration, contaminant mass removal, and cost.
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From page 130... ...
First, because of the time required for substantive results from remedial actions to be reflected by such measures, short-term measurements such as contaminant volume, mass, or concentration reductions will almost certainly be needed to supplement the long-term monitoring of toxicity. Second, there can be substances in the sediment or soil that cause a toxic response other than the contaminants of concern, making interpretation of results difficult.
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From page 131... ...
The results are used to compare to concentration-based remedial goals, to develop spatially averaged concentration values, and to construct concentration isopleths. In site spatially averaged concentration values, when combined with mass removal measurements (discussed later)
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From page 132... ...
As with almost all of the metrics discussed in this section, contaminant concentrations need to be interpreted in conjunction with other remedial performance measurements. Mass Removal Although closure requirements are traditionally posed as either concentration or risk-based standards, in some cases cleanup is stated in terms of mass removal.
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From page 133... ...
The percentage of total mass removed may also serve as a performance metric. The problem in implementing this type of metric is having an accurate estimate of the original contaminant mass; such information is frequently unknown.
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From page 134... ...
replacing static sampling and analysis plans with dynamic work plans. The following sections discuss each of these potential enhancements to remedial action monitoring programs, providing details on technology maturity and case studies.
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From page 135... ...
The most widely used method for improving remedial action monitoring network performance is to determine whether monitoring locations need to be changed (i.e., old monitoring locations abandoned or new locations added) or sampling intervals adjusted.
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From page 136... ...
a stepwise optimization that sequentially removes wells that are "redundant" for computing the average plume concentration. The Navy is clearly interested in optimizing its long-term monitoring systems, as evidenced by the recent development of guidance for the design and evaluation of groundwater monitoring programs (NAVFAC, 2000~.
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From page 137... ...
Monitoring and Data Analysis 137 ............................................
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From page 138... ...
138 Environmental Cleanup at Navy Facilities: Adaptive Site Management .
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From page 140... ...
140 Environmental Cleanup at Navy Facilities: Adaptive Site Management :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::: : ::A: : ^::::::::—.
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From page 141... ...
The obvious example of this is when a pump-and-treat system is converted to a strategy that relies on monitored natural attenuation.
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From page 142... ...
~ —7 ~ ~. ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: Incorporation of Sensors and Field Analytics into Monitoring Within the last ten years there have been significant advances in the quality of field analytical techniques, the number of technologies available, and their regulatory acceptability.
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From page 143... ...
Field analytics and sensors reduce overall characterization and monitoring costs because, in general, the per-sample cost associated with a field analytical analysis is much less than that of the corresponding laboratory analysis. As an example, a field-deployable GC/MS tuned for explosives work was used to support characterization of TNT- and DNT-contaminated soils at Joliet Army Ammunition Plant.
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From page 144... ...
, quickly identifying unexpected contaminant mobilization or other key potential system failures can be crucial to overall remediation success. Federal agency research and development programs have heavily invested in the last decade in field analytics and sensor technologies that can be applied to hazardous waste site characterization, remediation, and monitoring activities.
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From page 145... ...
A1/tternative Samp1/te Co1/~1/tection Techno1/togies Subsurface characterization and monitoring programs have traditionally relied on drilling techniques to obtain soil samples at depth and on permanent, screened and developed monitoring wells for acquiring groundwater samples. Just as there have been advances in field analytical techniques, so too there has been progress made in soil, sediment, and groundwater sample collection technologies.
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From page 146... ...
:~:A::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::~:E l:::^ Y:l~l:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::.: :.::: :: :.:.:.:-:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ............................................................................................................................. sample collection technologies can enable dynamic work plans and adaptive sampling and analysis programs, concepts discussed in the following section.
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From page 147... ...
SCAPS makes use of a cone penetrometer truck to push instrumented tips into the subsurface. The possibility of rapidly and inexpensively gathering detailed subsurface information in near real time via direct push technologies can change the way remedial action monitoring work is conducted for those settings amenable to direct push technologies.
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From page 148... ...
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From page 149... ...
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From page 150... ...
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From page 151... ...
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From page 152... ...
152 Environmental Cleanup at Navy Facilities: Adaptive Site Management ·:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: .:.:.:.::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::: _ :n :: :: s ~ .c A: it:: At}: .
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From page 154... ...
Multiple diffusion samplers deployed in a vertical array can provide an effective method of vertical contaminant profiling in monitoring wells. Optimal conditions would consist of the diffusion sampler or groundwater monitoring well screen being in direct contact with the surrounding formation, but correctly designed monitoring well sand packs are also appropriate.
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From page 155... ...
As alluded to above, dynamic work plans rely at least in part on direct push technologies and field analytic techniques. With these technologies, data collection can be adapted in response to the changing information needs of a remedial action, and the remedial action itself can be adjusted or adapted based on feedback from the data collection.
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From page 156... ...
In its cost and performance report, the USACE indicated that overall remediation costs were half of what would have been incurred if excavation had proceeded on the basis of existing historical datasets alone. There is also a place for dynamic work plans within groundwater remedial action monitoring.
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From page 157... ...
In the situation where a technology such as direct push was available for quickly acquiring groundwater samples from new locations, or for installing temporary monitoring points, the decision might be to expand the network in the short term to address unexpected trends or results in datasets. Alternatively, a monitoring system might include real-time data acquisition from dedicated in situ sensors.
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From page 158... ...
At individual sites under investigation, the Navy, in consultation with all stakeholders, should select a unit cost for the continued operation of the remedial action, above which the existing remedy is no longer considered a tenable option. The Navy should collect and analyze data to develop and validate predictive models of remedy performance.
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From page 159... ...
A concerted effort should be made to increase monitoring program effectiveness (and to reduce costs) by optimizing the selection of monitoring points, incorporating field analytics and innovative data collection technologies such as direct push, and adopting dynamic work plans and adaptive sampling and analysis techniques.
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From page 160... ...
2002. Induced fluorescence sensors for direct push systems.
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From page 161... ...
1997. Natural attenuation of chlorinated volatile organic compounds in a freshwater tidal wetland, Aberdeen Proving Ground, Maryland.
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From page 162... ...
2001. Guidance for optimizing remedial action operation (RAG)
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From page 163... ...
1999. Natural attenuation of fuel and chlorinated solvents in the subsurface.
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