Decision Support Tools i

Transcription

1 MODULE AT A GLANCE SLIDE DST-1 SLIDE DST-2 Condense Decisions through Iterative Data Collection and Assessment SLIDE DST-3 Same Tools...Different Toolbox SLIDE DST-4 What is a Decision Support Tool (DST)? SLIDE DST-5 Examples of SLIDE DST-6 On-line DST Matrix SLIDE DST-7 Advantages SLIDE DST-8 What are the Key Functions of? SLIDE DST-9 Examples of DSTs in the Matrix SLIDE DST-10 Schematic of DST Use SLIDE DST-11 Example Screening Level DST: BIOSCREEN SLIDE DST-12 BIOSCREEN Output: Plume Centerline SLIDE DST-13 FIELDS (Field Environmental Decision Support) SLIDE DST-14 FIELDS Interface SLIDE DST-15 Spatial Analyst and Decision Assistance (SADA) SLIDE DST-16 SADA User Interface SLIDE DST-17 Mini Case Study: Using DSTs to Guide and Communicate Project Decisions: Marino Bros. Scrapyard Site SLIDE DST-18 FIELDS: Visualize/Communicate Nature and Extent and Calculate Bulk Removal Volume SLIDE DST-19 SADA: Delineate Excavation Extent on a Rectangular Grid and Export Results SLIDE DST-20 Verify Sufficiency of CSM i

2 DST-1 DST-1

3 Condense Decisions Through Iterative Data Collection and Assessment One should not increase, Keep It Simple, beyond what is necessary, the Stupid number of entities required to explain anything Occam DST-2 Beginning early on and continuing throughout the life of a project, it may be necessary to (re)evaluate the benefit of action versus the benefit of collecting additional data (Occam s Razor). Information such as site history, contaminants potentially used and released, anticipated breakdown products of those chemicals, identification and refinement of potential exposure pathways, toxicity of compounds of potential concern (COPCs), and future land use are examined to identify the need for the collection of more data. With the help of experts and technical resources/guidance, regulators and project technical leads usually find a method to quantitate the magnitude or nature of a problem. Unfortunately, the environmental problems faced during site restoration projects are more complex than we can easily make conform to a simple set of algorithms, and classical statistical tools are generally inadequate at best. Data concerning nature and extent of contamination, sampling and analytical errors, and decision errors are usually assessed to the degree possible. Decisions broaden in scope but too often significant sources of uncertainty remain unexplored or their shear magnitude forces professionals to ignore them, or to rationalize why an adequate management response is not possible. DST-2

4 Same Tools Different Toolbox Tools» Query tools» Spatial interpolation» Secondary sampling» Delineation Toolboxes (DSTs)» SADA»FIELDS» VSP DST-3 Until recently, organized methods for the management of uncertainty were difficult to implement during the early stages of a project planning. However, with the advent of a new generation of decision support tools (DST), the technology is now widely available to manage uncertainty and condense the decisions using the data management and analysis tools provided in these new toolboxes. DSTs can help the project team organize data, test assumptions, develop sampling strategies, and winnow the universe of potential solutions to the environmental problem. DSTs such as SADA and FIELDS are comprehensive software programs that contain data management and querying tools that allow the user to either define a data dictionary or accommodate input from an external database or data source. They also include a variety of spatial interpolation tools, some which are easy to implement and some which require some prior familiarization with them (spatial interpolation will be discussed further in this section). Secondary sampling schemes allow new sample locations to be identified on the fly. DSTs also include tools that allow the user to delineate portions of a grid above regulatory thresholds and calculate the mass and volume of the contaminant and the cost of remediation or removal. DST-3

5 What is a Decision Support Tool (DST)? DSTs are interactive software tools used by decision-makers to help answer questions, solve problems, and support or refute conclusions. They can be incorporated into a structured decision-making process for environment site clean-up. DST-4 (DSTs) provide a concise representation of the essential decision making issues for a particular environmental decision. Environmental decisions that can be addressed with DSTs include site characterization, monitoring, supporting no further action (NFA) decisions, or selecting between alternative remedial decisions. DST software output allows comparisons to made between alternate remedial strategies based on decision variables such as cost and risk. However, DSTs are a particularly important component of the Triad approach because they allow data to be organized, visualized and analyzed in the field while the investigation is unfolding, thus condensing the decision-making process. DST-4

6 Examples of Decision Suport Tools DSTs vary in level of complexity, cost and ease of use:» Screening - Generally available in public domain, relatively easy to use, easy for stakeholders to understand. Examples: BIOSCREEN, BIOCHLOR.» Comprehensive - Can provide cradle-to-grave analysis for smaller sites or sites that are not too complex. May be public domain or proprietary. Examples: SADA, FIELDS.» Advanced - Sophisticated level of analysis and graphics. Most are proprietary. Require substantial investment in time and expertise. Examples: GMS, ArcGIS. DST-5 DSTs may be public domain or proprietary, and range in the level of sophistication and detail from screening level to very advanced. S S S Screening - Generally available in public domain, relatively easy to use, easy for stakeholders to understand. Examples: BIOSCREEN, BIOCHLOR. Comprehensive - Can provide cradle-to-grave analysis for smaller sites or sites that are not too complex. May be public domain or proprietary. Examples: SADA, FIELDS. Advanced - Sophisticated level of analysis and graphics. Most are proprietary. Require substantial investment in time and expertise. Examples: GMS, ArcGIS. DST-5

7 On-line DST Matrix Intended to help users screen public domain DSTs based on project-specific needs Consists of matrix (table), additional comments and bubble diagram that presents DSTs by functional area (e.g. Sample Plan Development) Many of the DSTs included in this matrix relate to use of the Triad approach Will be available on-line later this spring DST-6 The has conducted a brief evaluation of a representative group of 20 public domain DSTs and summarized the information gleaned from the evaluation in a matrix. will make the matrix available on-line to users who wish to screen DSTs based on project-specific needs. The DST evaluation was not a verification exercise or a comparative analysis of one DST against another. Rather, the goal of this exercise was to ascertain if a person with general technical experience could perform a basic task using the DST within a relatively short time frame. The front page graphic for the on-line matrix is shown on this slide. The graphic depicts 12 functional areas into which the 20 DSTs were grouped (some DSTs are included in more than one functional area). Clicking on a blue oval will take the user to a page that presents the tools in the corresponding functional area. Clicking on the green circle in the center of the graphic will take the user to the entire matrix of 20 DSTs. DST-6

8 Advantages Base maps can be imported easily Sampling coordinates output and input easily Initial and secondary optimized sampling schemes Most include multiple tools for data assessment Real-time export of results Compatible with most web applications Flexible Free DST-7 DSTs may be used as a gateway to a project's database. Many DSTs (such as FIELDS) provide tools to facilitate data capture and management. For instance, FIELDS provides a tool to create a user-defined data dictionary. Both FIELDS and SADA have a column matching utility that allows the user to quickly upload comma-delimited ASCII data files (which can be created by saving an Excel spreadsheet with a *.csv extension). A new generation of DSTs will be able to accommodate continuous data streams from field instruments. For instance, an -developed DST called Rapid Assessment Tool (RAT) has just been released. RAT is designed receive continuous data streams from real time instruments and merge the sampling data with location data from global positioning system (GPS) equipment. The data can be received and merged using wireless technology if the laptop is outfitted with a RS-232 port. The user should also understand that the DST will not provide presentation-quality graphics in many situations and must familiarize himself with the limitations of each program (many of these are described in subsequent slides). Finally, a DST in and of itself is not a silver bullet that will automatically reduce costs and streamline the effort on its own. The DST should be part of an overall Triad strategy that utilizes real-time measurement tools, relational databases and improved methods (electronic, if possible) for transferring data. DST-7

9 What are the Key Functions of the? Sampling Plan Development Visualization, Geospatial Interpolation and Geostatistics Modeling Remedial Process Selection Data Acquisition Data Management Long-Term Monitoring Optimization Statistical Analysis Emergency Response/Compliance Risk Assessment Site Screening Cost Estimation and Cost-Benefit Analysis DST-8 Each DST performs unique tasks, commonly referred to as functions. The DSTs in the matrix were categorized into 12 functional areas, as identified by website descriptions, software menus, and user manuals. The twelve functional areas depicted on the Front page of the web site divide the DST matrix into smaller sub-matrices (on separate web pages) that allow the user to hone in on the type of tools of interest. Individual DST s often perform many functions, therefore a single DST may be included under more than one functional area on the web page. DST-8

10 Examples of DSTs in the Matrix DST-9 This slide provides some examples of DSTs that are included in some of the functional areas. A table of all 20 DSTs included in the on-line DST matrix is provided in the insert pages that follow this slide. The matrix may be expanded with additional DSTs in the future. S S S S ARAMS is a software platform that incorporates various existing databases and models for source descriptions, media fate and transport, exposure pathways, intake and uptake, and effects (health impacts) into a conceptual site model (CSM) framework. BIOSCREEN is a natural attenuation screening model that simulates remediation through natural attenuation (RNA) of dissolved hydrocarbon species at petroleum fuel release sites. FIELDS Tools for ArcView are a collection of 11 independent ArcView extensions (modules) that provide spatial analysis in support of environmental decision-making. MAROS is a database application developed to assist users with groundwater data trend analysis and long term monitoring optimization at contaminated groundwater sites. DST-9

11 S S SourceDK is a decision support tool for developing a screening-level model to estimate groundwater remediation timeframes and associated uncertainties at sites where groundwater is contaminated by a source in the unsaturated zone. Visual Sample Plan (VSP) provides statistical solutions to sampling design problems. VSP helps the user select the correct number and location of samples so that a required confidence level for decision-making can be achieved. DST-10

12 Schematic of DST Use Start Select initial sample locations in DST and export Use contours to identify new locations Site characterized? Done No Yes Survey locations and collect samples Evaluate results against decision criteria Analyze samples using field-based methods Import results to DST and plot contour maps DST-10 DSTs can be used to guide a field program in conjunction with a dynamic work plan. This slide provides a schematic diagram of how a DST such as SADA or FIELDS can be integrated into the dynamic work strategy. DST-supported field decisions should be indicated in appropriate sections of the dynamic work plan, for instance on a decision flow diagram. The table on the following insert page shows how a DST-supported dynamic work strategy can increase the efficiency of an investigation, as compared to a traditional approach that uses a static work plan. DST-11

13 Table 1: Level of Effort Comparison Between a Traditional and a Triad Streamlined Data Management Approach Traditional Approach Streamlined Approach Data Collection: Location 20 minutes per location 1 minute per location Data Collection: Analytical 10 minutes per sample 10 minutes per sample Data Recording and QC 2 minutes per sample 1 minute per sample Upload Location and Analytical Data to Graphics Device 30 minutes 2 minutes Plot Location Data 5 minutes 5 minutes Post Analytical Data 5 minutes 5 minutes Contour Data 120 minutes 30 minutes Total Time 1,000 minutes 282 minutes DST-12

14 Table 2: Summary of DST Software Developer/Sponsor Description Web Link SADA University of Tennessee Integrated modules for environmental characterization and decision-making, including visualization, geospatial analysis, statistical analysis, human health risk assessment, ecological risk assessment, cost/benefit analysis, sampling design, and decision analysis. VSP PNNL VSP provides statistical solutions to sampling design, mathematical and statistical algorithms, and a user-friendly visual interface, while answering two important questions in sample planning: How many samples are needed? Where should the samples be taken? ARAMS Army Corps ERDC ARAMS incorporates various existing databases and models for source descriptions, media fate/transport, exposure pathways, intake/uptake,and effects (health impacts) into a conceptual site model (CSM) framework. The hub of ARAMS is an object-oriented CSM based on the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES). RESRAD Argonne Code for evaluation of risk posed by radioactively contaminated sites. NRC has approved the use of RESRAD for dose evaluation by licensees involved in decommissioning, NRC staff evaluation of waste disposal requests and dose evaluation of sites being reviewed by NRC staff. Follows risk assessment guidance for superfund. s.html DST-13

15 Software Developer/Sponsor Description Web Link FIELDS Region 5 The FIELDS Tools for ArcView (version 3.5) are a collection of ArcView-based extensions (modules) that include Sample Design (as well as a link to Visual Sample Plan, VSP), Database Query, Geospatial modeling and Analysis, and Human Health and Ecological Risk Assessment. NAS USGS/NFESC Natural Attenuation Software (NAS) was designed as a a graphical user interface for calculating estimates for the period of time required to achieve site-specific goals at sites contaminated with either fuels or chlorinated solvents. The user may choose to evaluate the effects of source reduction or complete removal in terms of meeting a user-specified contaminant concentration at a specific point of compliance. SourceDK AFCEE SourceDK is a computer decision support system for estimating remediation timeframes and assessing the uncertainty associated with those estimates. Programmed in the Microsoft Excel spreadsheet environment, SourceDK uses three relatively simple approaches to estimate remediation timeframes and the uncertainty in the timeframe estimate. All three approaches include methods to estimate the uncertainty in any remediation timeframe estimate oftware.htm DST-14

16 Software Developer/Sponsor Description Web Link BIOCHLOR AFCEE BIOCHLOR is a screening model that simulates remediation by natural attenuation of dissolved solvents at chlorinated solvent release sites. BIOCHLOR can be used to simulate solute transport without decay and solute transport with biodegradation modeled as a sequential first-order process within one or two different reaction zones. BIOPLUME III AFCEE BIOPLUME III is a 2D, finite difference model for simulating the natural attenuation of organic contaminants in ground-water due to the processes of advection, dispersion, sorption, and biodegradation. The model has been integrated with a sophisticated groundwater modeling platform known as EIS. A graphical user platform allows the user to create, enter and edit data for model simulation. CAMEO/ALOHA Nat'l Safety Council CAMEO is a system of software applications used widely to plan for and respond to chemical emergencies. The CAMEO system integrates a chemical database and a method to manage the data, an air dispersion model, and a mapping capability. All modules work interactively to share and display critical information in a timely fashion. iochlor.html ioplume3.html iochlor.html DST-15

17 Software Developer/Sponsor Description Web Link BIOSCREEN AFCEE BIOSCREEN is a screening model which simulates remediation through natural attenuation of dissolved hydrocarbons at petroleum fuel release sites. The software, programmed in the Microsoft Excel spreadsheet environment includes three different model types. The model is designed to simulate biodegradation by both aerobic and anaerobic reactions. MNA Toolbox Sandia (DOE) MNA toolbox identifies primary attenuation pathways, and points out processes that might mitigate against MNA for particular contaminants. Each contaminant module leads to a scorecard that uses site-specific input parameters to gauge the probable effectiveness of attenuation. MNA toolbox was designed to be used with the US Dept. of Energy s guidelines for implementing monitored natural attenuation. F/S PLUS Region 5 F/S Plus (version 1.5) is a stand-alone software that displays and allows analyses of 2D and 3D data. F/S Plus can performs many of the same functions as FIELDS Tools for ArcView, including data querying, visualization, interpolation and volume estimation. ioscrn.html /mnahome.html DST-16

18 Software Developer/Sponsor Description Web Link MAROS AFCEE MAROS is a decision support tool used to develop an optimization plan for the current monitoring system in order to efficiently achieve the termination of the monitoring program. It is based on statistical methods applied to site-specific data that accounts for relevant current and historical site data as well as hydrogeologic factors and the location of potential receptors. Groundwater Sensitivity Toolkit API The Groundwater Sensitivity Toolkit was designed to help site managers, water purveyors and regulators evaluate the sensitivity of a groundwater resource to a potential release of compounds of concern (e.g., an MTBE-oxygenated fuel) at a particular site. The toolkit runs on Microsoft Excel and comes with a user s guide. AMDTreat OSM & states AMDTreat is a computer application for estimating abatement costs for pollutional mine drainage, commonly referred to as Acid Mine Drainage or AMD. AMDTreat can assist a user in estimating costs to abate water pollution using a variety of passive and chemical treatment types. Johnson - Ettinger model A series of models for estimating indoor air concentrations and associated health risks from subsurface vapor intrusion into buildings, based on the analytical solutions of Johnson and Ettinger (2001) for contaminant partitioning and subsurface vapor transport into buildings. y.htm /risk/airmodel/johnson_ettinger.htm DST-17

19 Software Developer/Sponsor Description Web Link HSSM HSSM simulates flow of the LNAPL phase and transport of a chemical constituent of the LNAPL from the surface to the water table; radial spreading of the LNAPL phase at the water table, and dissolution and aquifer transport of the chemical constituent. RAT Region 5 Rapid assessment Tools (RAT) provide integrated data retrieval, geographic positioning system (GPS), geographic information system, (GIS), mapping and analysis tools through a simple yet robust interface that requires no post processing of GPS and GIS data. On-Site On-Site was developed to provide modelers and model reviewers with prepackaged tools ( calculators ) for performing site assessment calculations, standardized contaminant characteristic data (including data on fuel composition and models for leaching from fuel lenses) and simple analytical models that allow the user to test the effects of uncertainty in parameter estimates on model predictions. ssmwin.html (have contacted the developers about this) part-two/onsite/ DST-18

20 Software Developer/Sponsor Description Web Link Scribe Scribe is a software tool developed to assist in the process of managing environmental data. Scribe captures sampling, observational, and monitoring field data. Examples of Scribe field tasks include Soil Sampling, Water Sampling, Air Sampling and Biota Sampling. Scribe can import electronic data including Analytical Lab Result data (EDD) and Sampling Location data such as GPS. Scribe supports handheld extensions, Scriblets, to capture and import sampling and monitoring data collected on handheld PDAs. htm DST-19

21 Example Screening Level DST: BIOSCREEN DST-11 BIOSCREEN is a tool originally developed to evaluate the efficacy of remediation by natural attenuation (RNA) at Air Force fuel spill sites. BIOSCREEN was developed by researchers from Rice University in conjunction with the Air Force Center for Environmental Excellence (AFCEE). Because it is closely linked to AFCEE s protocol for the evaluation of MNA at fuel sites, it provides an excellent example of a DST that compiles expert knowledge into a stored process. The BIOSCREEN input screen is an Excel worksheet where the user enters information on site hydrogeology, soil and chemical properties as well as plume dimensions. Given a set of parameter values and plume dimensions, the model calculates hydrocarbon concentrations along the plume centerline in order to answer the question how far will the dissolved contaminant plume extend if no engineered controls or further source zone reduction measures are implemented? BIOSCREEN simulates degradation of petroleum compounds by both aerobic and anaerobic organisms. BIOSCREEN can be used for two different types of applications. S S As a screening model to determine if RNA is feasible at a site As the primary groundwater model at smaller sites DST-20

22 This type of flexibility is characteristic of DSTs. For instance it is often useful to scope a potential remedy, such as RNA, before committing significant resources to implementing a thorough investigation of its potential applicability. To implement BIOSCREEN in the screening mode, the project team should collect a suite of geochemical analyses from a few wells inside and outside of the impacted area. Literature values can be used for most of the remaining parameters at this stage in the investigation. If RNA appears feasible, these parameter values can be refined through investigation before running the model again. DST-21

23 BIOSCREEN Output: Plume Centerline DST-12 BIOSCREEN contains a first-order decay model and an instantaneous reaction model. AFCEE recommends the instantaneous reaction model for most sites. Geochemical indicator data are required to run the instantaneous reaction model. These data include concentrations of electron acceptors consumed in redox reactions (dissolved oxygen, nitrate, sulfate) and metabolic byproducts (ferrous iron and methane) generated from redox reactions. The output pictured above (as well as the input screen on the previous slide) is an actual model run from a screening level application of BIOSCREEN. The observed data is the black square representing the benzene concentration in groundwater near the bottom of the graph at a distance of 30 feet (along the plume centerline). The position of the square well below the red line (which represents predicted concentrations if NO biodegradation was occurring) indicates some biodegradation of benzene has likely occurred. However, the first-order decay model (blue line) was run with a conservative half-life that was at the very upper limit of the range of reasonable benzene half-life values provided in the BIOSCREEN manual. Furthermore, the instantaneous model predicts the dissolved plume should disappear immediately downgradient of the source area, based on the biodegradation capacity of the aquifer (calculated from the difference in concentration of electron acceptors and metabolic byproducts between background and in-plume wells). DST-22

24 Therefore, the project team concluded that the biodegradation was occurring, but at a much slower rate than predicted by either model. Divergence between predictions and observations lead the project team to question why there is not better agreement. One possibility is that the concentration of one electron acceptor sulfate is so high (over 10,000 ppm) that it may inhibit, rather than enhance, microbial activity at the site. Thus, a new set of questions and hypotheses are used to further develop the CSM and will be evaluated during the development of active remedial alternatives (RNA having been ruled out). DST-23

25 FIELDS (FIeld EnvironmentaL Decision Support) The FIELDS system is a set of software modules designed to organize and analyze site and contamination data FIELDS can be downloaded at: 7Efields/ DST-13 FIELDS requires ArcView 3.x and Spatial Analyst 1.1 or later. The most recent release of FIELDS allows VSP to be accessed as an ArcView extension. Thus, the VSP sampling schemes can be run within FIELDS. FIELDS has robust graphical capabilities because it runs on an ArcView platform. Contours can be overlain on air photos or AutoCad base maps. AutoCad layers become individual themes in ArcView. Point, polygon and text themes may be turned on or off or overlain on one another. Custom layouts can be created and saved for each analyte or each area of interest. ArcView is a license-protected commercial software product that must be purchased from ESRI. A two-day training course in ArcView is recommended to become proficient in ArcView. DST-24

26 FIELDS Interface Plot Layout Graphics View DST-14 This slide shows the two types of ArcView user interface. The graphics view is the window in which data analysis is conducted. The map/graphics window in center and table of contents (TOC) at left are used in both ArcView and FIELDS. The toolbar at top has additional menu items specific to FIELDS on the right-hand side. If F/S Plus and VSP extensions are loaded, they will also appear on the toolbar. The TOC displays all of the themes that have been loaded into the view. All of the FIELDS tools and analyses require the user to select one or more themes in order to conduct the analysis. For instance, the contouring algorithms and sampling schemes generally require the user select a point theme (for data values) and polygon theme (to bound the analysis) in order to run. The results of most analyses and sampling tools (except adaptive fill) are automatically saved in a theme. The plot layout is used arrange plot elements (view, legend, title) for the plotting of maps and final products. The view window in upper right is incorporated into the plot layout in lower left in this example. DST-25

27 Spatial Analyst and Decision Assistance (SADA) SADA is an evolving freeware product targeted to individuals performing environmental assessments in support of decision-making SADA can be downloaded at: sada/ DST-15 Spatial Analysis and Decision Assistance (SADA) is free software that incorporates integrated modules for visualization, geospatial analysis, statistical analysis, human health risk assessment, ecological risk assessment, cost/benefit analysis, sampling design, and decision analysis. The capabilities of SADA can be used independently or collectively to address site specific concerns when characterizing a contaminated site, assessing risk, determining the location of future samples, and when designing remedial action. A number of the capabilities present in SADA are also present in the FIELDS (Fully Integrated Environmental Location Decision Support) system. DST-26

28 SADA User Interface DST-16 The SADA user interface has three components: the graphics view on the left (where the maps and data plots are viewed), the control panel on the right (where the user selects parameters/enters data for sampling schemes, geostatistics, search neighborhoods and decision levels); and the menu/toolbar at the top of the view (where the user can select the type of map or plot with the buttons or choose between major program functions). DST-27

29 Mini Case Study: Using DSTs to Guide and Communicate Project Decisions: Marino Bros. Scrapyard Site Brownfields site on banks of Ohio River PCOCs are metals and PCBs Reuse plan: mixed commercial/recreational The preliminary CSM was used to develop estimates of expected volumes of soil to be removed in order to clean up site for reuse. Two comprehensive level DSTs were used:» FIELDS was used to query & contour data, identify drivers and perform bulk mass and volume calculations.» SADA was used to contour data on a rectangular grid, estimate average concentrations and export estimated values in Excel spreadsheets for further calculations.» A do-it-yourself DST was created using Excel spreadsheets to incorporate complex decision logic into cost estimating process. DST-17 The Marino Scrapyard site is a riverside Brownfields in western Pennsylvania. The scrapyard ceased operation in The local municipality now owns the site and wants to redevelop it for mixed commercial/recreational use. An RI was conducted by the Pennsylvania Department of Environmental Protection (PADEP). The principal media of concern are surface soil and subsurface soil to the approximate depth of the groundwater table (12 feet below ground surface). The targeted contaminants of concern (COCs) for soil included seven metals and two polychlorinated biphenyls (PCBs). Site specific standards were developed for the COCs during a risk evaluation. OSRTI s Brownfields Technical Support Center was tasked to prepare a preliminary CSM from the RI data and use the preliminary CSM to develop a dynamic work planning strategy and a statement of work (SOW) that PADEP used to guide an expedited site cleanup. The SOW provided the quantities (excavation volume and disposal volumes) for contractors to bid on. DST-28

30 FIELDS: Visualize/Communicate Nature and Extent and Calculate Bulk Removal Volume Isoconcentration maps highlight areas of overlap, allowing project team to focus on a smaller suite of analytes. DST-18 s FIELDS was used to create high-quality 2D contour maps. Concentrations above site-specific, risk-based standards were contoured using the natural neighbor (NN) interpolation scheme in 2D. Results were plotted on an aerial photograph. Because FIELDS supports only 2D interpolation, the data were queried in 2-foot depth intervals to create slice maps. Comparison of maps representing successive 2-foot slices allowed a quasi-3d analysis of the data. The mapping exercise showed lead to be the most widespread COC and suggested that removal of lead above the site-specific standard would remove all other constituents that exceeded their site-specific standards. Thus, lead was used as an indicator COC for the purpose of performing volume calculations. FIELDS calculated the areas where lead exceeded the site-specific standard and multiplied the areas by the two-foot thickness of each slice to arrive at the volume to be removed. The Remediation Tool function in FIELDS was used to calculated the total volume of soil to be removed. The total volume was used as a quantity for contractors to bid on. DST-29

31 SADA: Delineate Excavation Extent on a Rectangular Grid and Export Results Contour Map Area of Concern (AOC) Map Estimated Depth of Excavation for Bidding Purposes (graphic was created outside of SADA) DST-19 In terms of disposal, the biggest cost drivers were hot spots of mercury and PCBs, which have more stringent disposal requirements than lead. Specifically, the excavation volume needed to be subdivided into smaller volumes for disposal at different classes of landfills, based on land disposal restrictions, estimated toxicity threshold values (estimated using the Toxicity Characteristic Leaching Procedure [TCLP] 10X guideline) and specific criteria for local landfills. SADA provided a convenient interface to contour and export the data to an Excel-compatible file format. Interpolated concentrations of lead, mercury and PCB congeners provided the basis for calculating the volumes of soil that would go to Class I or Class II landfills under various scenarios. SADA s AOC module allows the user to highlight all cells where the average concentration exceeds a user-defined action level. Estimated concentrations (from the contour map) and AOC results (above or below action level) were exported from SADA to an Excel file. Further processing was conducted in Excel. Together, the two DSTs provided a variety of visualization, estimation (contouring) and delineation tools that were brought to bear on the analysis. Sufficiency of the CSM and its underlying data set was tested by contouring the data using both tools, comparing the results and conducting a sensitivity analysis to determine a range of remediation costs that encompassed uncertainty inherent in the CSM. DST-30

32 Verify Sufficiency of CSM DST-20 A key tenet in the Triad methodology is that data collection and analysis is driven by the need to mature the CSM until just enough data is collected and interpreted for the project team and stakeholders to make an informed decision about the site, whether it be the need for a remedy, the selection of a remedial alternative, or a decision regarding property ownership or development. The Triad methodology emphasizes planning for this decision point. The iterative nature of a Triad investigation allows for the project team to constantly reevaluate the CSM with each new round of sample collection and analysis. With each iteration, the CSM is tested, discussed and probed for weaknesses by the project team. DSTs provide a platform for this process. In the ideal Triad setting, the project follows each of the steps outlined in this module. Occasionally, the Triad approach is applied to data already collected and compiled and the Triad methodology is used to bridge the gap between a poorly-developed CSM and a concrete plan for remedial action. In the following example, the site s remedial investigation (RI) was more or less complete at least in the eyes of project stakeholders. The CSM, as it was presented in raw form in the RI, did not provide a sufficient basis to estimate the cost of a planned removal action. The project stakeholders, therefore, needed tools and a method for interpreting the data to better develop the CSM, then deciding if the CSM was mature enough to guide planning and procurement for the removal action. DST-31