&EPA United States Environmental Protection Agency TOOLKIT FOR PREPARING CERCLA RECORDS OF DECISION SEPTEMBER 2011 ------- Environmental Protection m m United Agency TOOLKIT FOR PREPARING CERCLA RECORDS OF DECISION This effort is the culmination of a multi-year collaboration with the Department of the Navy (DoN) to ways to produce higher quality and more user-friendly Records of Decisions. EPA wishes to acknowledge the DoN for its unflagging assistance, and technical support, especially the graphics production. This product has significantly improved through those who have worked with EPA over the and EPA gratefully acknowledges their contributions. ------- TOOLKIT INTRODUCTION This toolkit consists of sixteen exhibits and each includes a "Recommended Toolkit Tip to help improve the quality and transparency of data presentation in a Record of Decision. This document provides guid- ance to Regional staff regarding how the Agency intends to inter- pret and implement the NCR which provides the blueprint for CERCLA implementation. How- ever, this document does not substitute for those provisions or regulations, nor is it a reg- ulation itself. Thus, it cannot impose legally binding require- ments on EPA, sites, or the reg- ulated community and may not apply to a particular situation based upon the circumstances. Any decisions regarding a par- ticular situation will be made based on the statute and the regulations, and EPA decision- makers retain the discretion to adopt approaches on a case-by- case basis that differ from the guidance where appropriate. 2See for example 40 CFR 300.400 and the guidance docu- ment entitled: "A Guide to Pre- paring Superfund Proposed Plans, Records of Decision, and Other Remedy Selection Decision Documents" (OSWER 9200.1-23P), July 1999. This document provides Remedial Project Managers (RPMs) with a resource to help improve the public transparency and understanding of Superfund Records of Decision (RODs) for remedy decisions developed in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)1 using communication tools de- signed to enhance the decision document's presentation (Exhibits 1-16). This document provides suggestions on means to convey information graphically and visually in a ROD or in a separate outreach document. By using these tools, RPMs may help clarify the selected remedy (Figure 1) and effectively convey information in a format that thoroughly yet concisely presents the full rationale for the remedy decision. These tools are meant Figure 1 to supplement the ROD decision document, not replace it. The suggestions or tools in this document do not substitute for the statutory or regulatory requirements for a ROD or for related guidance documents2. The ROD should be a defensible, stand-alone document that memorializes the remedy decision in an appropriate level of detail, as discussed in EPAs ROD Guidance. Sometimes, in attempts to be all inclusive or overly thorough, a ROD includes extraneous inform- ation or provides an excessive amount of detailed information from previous documents. This may inad- vertently affect the public's ability to understand the ROD. RPMs may be able to summarize the key facts from prior site-related documents and use the tools described herein to enhance the decision document's presentation to provide a more succinct and understandable ROD. For example, by using summary graphics, figures, and tables, supported by appropriate text, an RPM may be able to better illustrate the data, analysis, and rationale to better explain the remedy selected in the ROD. Because there is no "one size fits all" template, it is generally important during development of a ROD to include the level of detail recommended by EPAs ROD Guidance and consider the use of streamlining and visualization tools for better site-specific data or information presentation. The example exhibits presented in this document track the EPA ROD outline as provided in the "A Guide to Preparing Superfund Proposed Plans, Records of Decision, and other Remedy Selection Decision Documents" (OSWER 9200.1-23P) July 1999, on page 6-2. Each exhibit provides recommended tips that suggest how and where to consider including tools like tables and graphics in a ROD. These recommended streamlining and visualization tools may also be effective in the preparation of other documentation related to the CERCLA remedy selection process, such as Remedial Investigations and/or Feasibility Studies. This document is designed to be viewed electronically. This format allows the reader to zoom into the detail presented in the color graphics. Please note that some reformatting may be required for printing. EPA plans to create a web site that will provide additional information on available visualization and decision support tools (i.e., software packages). These support tools often can be used to present data/ information similar to the exhibits in this document. The web site is intended to provide a resource of available free-ware and commercial computer software. The data visualization tool listing will not provide endorsements or recommendations of specific resources but instead will provide potential users with examples of tools available and their stated applications. EPA also intends to provide a series of documents on Conceptual Site Models designed to discuss the context for potential use of visualization tools. The science supporting data visualization is advancing rapidly and we anticipate the web site will continue to capture these advances. ------- TOOLKIT EXHIBITS Exhibit 1: Road Map of the Key Elements of Remedy Selection Exhibit 2: Data Certification Checklist for RODs with Multiple Operable Units/Sites Exhibit 3: Site Layout and Photographs Exhibit 4: History of Site Investigations and Actions Exhibit 5: Nature and Extent of Contamination Exhibit 6: Conceptual Site Model Exhibit 7: Current and Potential Future Land and Resource Uses Exhibit 8: Risk Assessment Summary Tables Exhibits: Basis for Action Exhibit 10: Remedial Action Objectives for Chemicals of Concern Requiring Action Exhibit 11: Summary of Remedial Alternatives Exhibit 12: Evaluating Monitored Natural Attenuation as a Remedial Alternative Exhibit 13: Comparative Analysis of Alternatives Exhibit 14: Description of Selected Remedy Exhibit 15: Expected Outcomes of the Selected Remedy Exhibit 16: Optional Reference CD ------- EXHIBIT 1. ROAD MAP OF SOME KEY ELEMENTS OF REMEDY SELECTION Recommended Toolkit Tip Exhibit 1 visually displays some of the possible graph- ic tools that should be con- sidered for incorporation into a ROD; however, this Exhibit itself should not be included in the ROD. These tools can help explain the CERCLA remedy selection decision process, and help promote meaningful com- munity involvement, which typically is a key compo- nent throughout that pro- cess. Similar to a direc- tional road map, there is a starting point (CERCLA Release) and a finish line (Expected Outcomes) for the site, with many key stops along the way. y CERCLA Release ' Conceptual Site Model Risk Assessment D Basis for Action Remedial Action Objectives I IHI Remedial Alternatives Comparative Analysis Selected Remedy IHI Expected Outcomes Conduct site investigation activities to identify the CER- CLA release, surface charac- teristics, hydrogeology, nature and extent, and fate and trans- port mechanisms to develop the conceptual site model (CSM). Remedial Action Objectives Risk Assessment Future Adult Resident Future Child Resident ^^^B Subsurface Soil Groundwater Subsurface Soil ^^••1 Inhalation Ingestion Incidental Ingestion Inhalation ^^^m C11-C22 Aromatic Hydrocarbon Fraction VC C11-C22 Aromatic Hydrocarbon Fraction ^^^^H 3,062 mg/hg 6.52 ug/L 3,062 mg/kg NA 1.5E-04 NA NA 2.92 0.0 1.30 2,92 NA 2.0E-05 NA NA 0.711 0.0 0.159 0,711 Not carcinogenic 1,9 Not carcinogenic 3x102 0.0 3x10-' Results of the risk assessment are used to identify media and chemicals of concern (COCs) warranting a response action based on current and potential future land and resource use. Refine the CSM to identify the current and potential future land and resource uses and potential exposure pathways for risk evaluation. Remedial alternatives are devel- oped for the media and COCs warranting a response action. Remedial Alternatives Develop Remedial Action Objec- tives (RAOs) and cleanup levels to address all media and COCs that warrant a response action. D Basis for Action 1— Mo Action 2-MNA/LUCs 3-ERD using existing Horizontal Well and Downgradient ERD Injections / Monitoring / LUCs None MNA LUCs Enhanced Anaerobic Bioremediation through Horizontal Well Enhanced Anaerobic Bioremediation via Downgradient Injections LUCs Allow the COCs to breakdown naturally over time Groundwater monitoring and reporting to assess the progress of natural attenuation over time LUCs to prevent exposure to groundwater and petroleum hydrocarbon-impacted soil Injection of electron donors through existing horizontal well to stimulate anaerobic biodegradation of CVOC source by reductive dechlorination Injection of electron donors in wells downgradient from horizontal well, upgradient of Courthouse Bay, to stimulate anaerobic biodegradation of CVOCs by reductive dechlorination and minimize migration of CVOCs to Courthouse Bay LUCs to prevent exposure to grouncfwater and petroleum hydrocarbon-impacted soil Capital Cost Annual operation and maintenance (O&M) Total Present-Worth Timeframe Capital Cost Annual O&M Total Present-Worth Timeframe Capital Cost Annual O&M Total Present-Worth Timeframe $0 $0 $0 30 years $13,500 $48,249 $763,736 30 years $854,751 $48,295 $1,946,816 20 years Conceptual Site Model Potential Risk to Future Resident: ingestion of Groundwa *W— ~rr Horizontal Well - Groundwater Flow Direction Location of Existing/Former UST Hazmat Storage Vehicle Washdown Areas Operable Unit 21 TCE Concentrations ^H 50 < x < 1 00 ^g>L •• 5 < x * 50 (jg'L ^ 2 8 < x < 5 M3/L Human Health Subsurface soil Current or potential drinking water resource Sediment/Surface water Subsurface soil Sediment/Surface water Recreational & Training No unacceptable risks Mot applicable Mon-cancer hazard index > 1 Cancerrisk >10"4 Cancerrisk>10"4 WCL exceedance Vinyl chloride No unacceptable risks No unacceptable risks Not applicable No unacceptable risks WCL exceedance Cancerrisk >10"4 Mot applicable Mot applicable Remedial alternatives are evaluated against the nine criteria and one another for a comparative analysis. Legend * Monitoring Well Extent ofTCE Exceed B Extent of VC Exceeda Extent of DCE Exceed Extent of Benzene Exc IngestionofVOCSin groundwater under potable use scenario Direct exposure to Detroleum hydrocarbons in soil under residential use scenario and leaching sciential to groundwater Restore groundwater quality based on the classification of the aquifer as a potential source of drinking water and to prevent human ingestion of water containing COCs at concentrations above NCGWQS or MCL standards, whichever is more stringent until cleanup levels have been obtained. Prevent future residential exposure to petroleum hydrocarbon-contaminated soils above the NC HWS SSL and minimize transport to groundwater. Air sparge system Operate system until groundwater cleanup levels are met [expected 5 years) to achieve UU/UE. Maintain LUCs and LTM until groundwater COCs are at or below cleanup levels for four consecutive monitoring events to establish UU/UE. Maintain LUCs on soil for continued industrial landuse. The components of the Selected Remedy mitigate risk to achieve RAOs consistent with current and potential future land and resource uses. Comparative Analysis Based on the comparative analysis, a remedy is proposed, then after opportunity for public com- ment, selected that meets the threshold criteria and achieves RAOs. ------- EXHIBIT 2. DATA CERTIFICATION CHECKLIST FOR RODS WITH MULTIPLE OPERABLE UNITS/SITES ROD Section Declaration Data Certification Checklist Recom mended Toolkit Tip For RODs addressing multiple sites or Opera- ble Units, a table may be used to help the reader locate important infor- mation in each individual ROD, such as information for each recommended element of the sam- ple Data Certification Checklist. ROD Section Number Data Chemicals of concern and their respective concentrations Baseline risk represented by the chemicals of concern Cleanup levels established for chemicals of concern and the basis for these levels How source materials constituting principal threats are addressed Current and reasonably anticipated future land-use assumptions and current and potential future beneficial uses of groundwater used in the baseline risk assessment and ROD Potential land and groundwater use that will be available at the site as a result of the Selected Remedy Estimated capital, annual operation and maintenance (O&M), and total present worth costs, discount rate, and the number of years over which the remedy cost estimates are projected Key factor(s) that led to selecting the remedy (i.e., describe how the Selected Remedy provides the best balance of tradeoffs with respect to the balancing and modifying criteria, highlighting criteria key to the decision) OU/Site1A-1 OU/Site1H OU/Site6A* 1.2 1.4 1.4 1.5 1.3 1.8 1.8 1.7 2.2 2.4 2.4 2.5 2.3 2.8 2.8 2.7 3.2 3.4 3.4 Not Applicable 3.3 Not Applicable Not Applicable Not Applicable "no action is required for OU/Site 6A ------- EXHIBIT 3. SITE LAYOUT AND PHOTOGRAPHS Administrative Record Resources ROD Section Decision Summary Site Name, Location, and Brief Description Recom mended Toolkit Tip Embedding regional and base location images as insets within a figure showing the detailed site layout often can effec- tively consolidate infor- mation previously dis- played in several figures. This type of comprehen- sive graphic combined with historic and current site photographs, if avail- able, can help provide the reader with a better understanding of the site. The figure should present accurate information on the site boundary, current conditions that encompass the source(s), or release area(s) and the extent of contamination. As noted in the 40 CFR 300.4, CERCLA response actions include "where a hazardous substance has been dep- osited, stored, disposed of, or placed, or otherwise come to be located." Therefore, the extent of contamination should not be truncated by artificial/ physical boundaries (e.g., property line, roadways, water bodies). Synthesize Summarize LEGEND « Shallow Monitoring Well Location • Deep Monitoring Well Location Site 5 Waste/BuVnt Soil Area |C3 Site 5 Boundary ^1 Lower Drainage I—I Upland Drainage Existing Wetland Area A Former Building ------- EXHIBIT 4. HISTORY OF SITE INVESTIGATIONS AND ACTIONS ROD Section Decision Summary Site History & Enforcement Activities Recom mended Toolkit Tip To enhance the presen- tation of the site history and enforcement activities discussion, a summary table and/or graphic depicting previous investigations/act- ions may be used to explain how the site has been adequately investigated util- izing an appropriate sampl- ing strategy. The level of detail in a summary table should be adequate to me- aningfully supplement the ROD's discussion of all pert- inent investigation/action in- formation as the site has gone through the CERCLA process. Including a figure can be an effective way of illustrating the sample locations with good spatial coverage, app- ropriate medium, and rele- vant analysis groups based on the CERCLA release or threat of release. Emerging contaminants (e.g., perchlo- rate, 1,4-dioxane) should not be overlooked. For extensive site histories where a text summary may be more appropriate, the use of a time-line can help present a graphic depic- tion of the CERCLA inves- tigations/actions that have occurred. Administrative Record Resources Proposed Plan sitenschooiofMiisicpiatingShop Feasibility Study Technical Memorandum te 11 - school of Music plating shop II Revised Human Health Risk Assessment SRI Addendum Naval Amphibious Base Little Creek Virginia Beach, Virginia Pwraatw Department of the Navy Naval Facilities Engineering Command CH2MHILL Supplemental Remedial Investigation for Site 11 School of Music Plating Shop Naval Amphibious Base Little Creek Virginia Beach, Virginia Decision Docunienr Site 11: School of Miuic Plating Shop Naval Amphibious Base Lillle Creek Naval Facilities Engineering Com man Norfolk. Virginia LANTDIV CLEAN Program Interim Removal fiction Final Closeout Report Site 11 • School of Music Plating Shop Naval Amphibious Base Little Creek Norfolk, Virginia Neva! Construction Battalion Center Naval Facilities Engineering Command Port Hueneme, California 93043-5000 il Investigation Report ous Base Little Creek Beach, Virginia L PROGRESS REPORT 1 VERIFICATION STEP aval Amphibious Base, Little Creek l-M USONM EVI AL .SERVK' US snrfl WIIKELER v: Livington, \*« ,(«> (\iNlr.ii1 Sn247ll-Ji'J.|l 4NN AKEK F-\VIlM»iMKNTAL, IT iSMENT STUDY OF IBIOU5 BASE, LITTLE CREEK WIMIA ATLANTIC DIVISION NAVAL FACILITIES ENGINEERING COMMAND NORFOLK, VIRGINIA Synthesize Summarize 2 Decision Summary «orvandEnforcementActivi 1984 Initial Assessment Study 1986 , — Confirmation Study • 1984 1994 1991 r Interim Remedial Investigation Investigation / Feasibility study 1994 r Decision Document 1994 2000 1999 National \ US"ng ~ Screening Level . Ecological Assessment 2001-2006 Investigation 1999 2001 2006 2007 Feasibility Proposed Study Plan 2007 M ' ' r ------- EXHIBIT 5. NATURE AND EXTENT OF CONTAMINATION ROD Section Decision Summary Site Characteristics Recom mended Toolkit Tip Comprehensive figures may be used to sup- port the ROD'S discus- sion concerning the cur- rent relationship between potential sources, subsur- face geology and hydro- geology, and the lateral/ vertical extent and mag- nitude of contamination. The figures should reflect any uncertainties in the data presentation. For sites with groundwa- ter plumes or subsurface contamination, a figure can help portray an accu- rate, detailed depiction of both the horizontal and vertical extent of contam- ination, which can also assist in better under- standing the conceptual site model. Administrative Record Resources j.1.2 Vfefland Surface Debris Delim 5.1 investigation Results I r Synthesize Summarize - ' """ 1=1 XJj^Siyf'™ > ' "''•i'" ".'."":"" Fijure 9 Ctll'jrinatcd S -CHaiVlHILL ------- EXHIBIT 6. CONCEPTUAL SITE MODEL Administrative Record Resources ROD Section Decision Summary Site Characteristics Recom mended Toolkit Tip A comprehensive concep- tual site model graphic generally helps illustrate the site layout, hydro- geologic setting, source area(s) and contami- nated medium, fate and transport mechanisms, exposure pathways, and potential current and future receptors. Current/Future Industrial Worker: Inhalation of potential groundwater ind EH r=n r:s;.: -,.--j na rsn Storm Sewer System Trespasser Ingestion and Dermal Contact of Surface Water & Sediment; Ingestion, Deimal Cornaa . & Inhalation of Surface Soil Current Future Industrial Worker Ingestion of Groundwater; Inlia'ation of Groundwater Vapors (Indoor Air); Ingestlon, Dermal Contact. & inhalation of Soil Future Construction Worker: Dermal Contact of Groundwater; inhalation of Ground water Vapots; Ingestion, Dermal Contact, • I .=:'.,, ./ u Synthesize Summarize Future Construction Worker Ingestion, dermal contact and absorption of groundwater, sediment, and subsu Terrestrial Flora and Invertebrates: Direct contact and root uptake from surface soil, surfac water, and sediment; Ingestion and direct contae with surface soil, surface water and sediment Benthic Dwelling and Aquatii SJCA Non Site. related Sources Current/Future Resident: Ingestion, - dermal absorption and inhalation of groundwater; Ingestion and de absorption of surface soil; Inhalation surface soil Trespasser/Visitor: Ingestion anc dermal con tact of surface water and sediment; Inhalation and dermal absorption of surface soil ------- EXHIBIT 7. CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES ROD Section Decision Summary Current and Potential Future Land and Resource Uses Recom mended Toolkit Tip A map can be an extremely effective tool for depicting all onsite and adjacent land/ resource uses, including recreational use of adjacent surface waters and ground- water classification for cur- rent and potential future use. Refer to page 7 of "Summary of Key Existing EPA CERCLA Policies for Groundwater Restoration" (OSWER Directive 9283.1- 33, June 26, 2009.) The map can also help ensure appropriate remedial action objectives are identified for the potential receptors. Maps also can help show consideration of land use assumptions, relevant land and resource management plans, zoning maps, 20-year development plans, reuse assessments, and nearby development activity. The site layout figure or addi- tional figures/photographs/ planning documents also may be useful for depicting current and potential future land and resource uses. Refer to page 2 of "Land Use in the CERCLA Rem- edy Selection process" (OSWER 9355.7-04, May 25,1995.) ------- EXHIBIT 8. RISK ASSESSMENT SUMMARY TABLES Administrative Record Resources ROD Section Decision Summary Summary of Site Risks Recom mended Toolkit Tip Summary tables may be used to help explain the ROD'S discussion describ- ing the risk assessment procedures and to help summarize the unac- ceptable risks; the sum- mary tables can include information on receptor scenarios, medium, expo- sure pathways, chemicals of concern, exposure point concentrations, and tox- icity values. These tables should be supplemented with cumulative risk sum- mary tables to help ensure all risk assessment consid- erations discussed in EPA's ROD Guidance (1999) are addressed. Summary tables can help explain how the risk assessment reflects current toxicity values, risk assess- ment methodologies and guidance, and site condi- tions (e.g., current residual risk if interim actions were taken). The tables also can help explain how all appro- priate exposure pathways have been evaluated in a manner that considers cur- rent and potential future use (e.g., indoor air expo- sure, risk to future on-site workers). Synthesize Summarize ------- EXHIBIT 9. BASIS FOR ACTION ROD Section Decision Summary Summary of Site Risks Recom mended Toolkit Tip Maps and tables can help explain the results of the risk assessment and to help identify medium and chemi- cals of concern (COC) war- ranting a response action, considering current and pot- ential future land use. These tools can help document the appropriate risk manage- ment decisions for risks exceeding threshold criteria and for chemicals of poten- tial concern identified in screening-level risk assess- ments (e.g., comparison to background, slight exceed- ance of threshold criteria). A summary table with sup- porting text may be use- ful in identifying the poten- tial receptors, impacted medium, land and resource uses, and COCs warrant- ing response action under CERCLA A summary table can help present the con- centrations of COCs in each medium and associated risk factors may also be included to illustrate the magnitude of the threat to human health and the environment posed by the site. Graphics to help explain the Basis for Action can also assist in the ROD'S discussion of the Remedial Action Objectives (RAOs) and the cleanup levels (see Exhibit 10). Legend Monitoring Wei Extent of TCE Exceedances Extent of VC Exceedances Extent of DCE Exceedances Extent of Benzene Exceedances Extent of Soil Contamination Reasonably Antici pated Receptor Media Land Use Human Health Ecological Surface soil Subsurface soil Groundwater Sediment/Surface water Surface soil Subsurface soil Groundwater Sediment/Surface water Residential Residential Current or potential dri nki ng water resource Recreational & Training Habitat No pathway Habitat Habitat Chemical of Concern No unacceptable risks Arsenic Benzene TCE cis-1,2-DCE 1,1-DCE Vinyl chloride No unacceptable risks No unacceptable risks Not applicable No unacceptable risks No unacceptable risks Basis for Action Not applicable Non-cancer hazard index of 1 A Cancer risk of 1.2x1 0'4 Cancer risk of 2.3 x10"3 Max concentration = 136 \iglL (exceeding MCL of 70 |jg/L) Max concentration = 34 |jg/L (exceeding MCL of 7 |jg/L) Cancer risk of 1.7 x1CT4 Not applicable Not applicable Not applicable Not applicable Not applicable ------- EXHIBIT 10. REMEDIAL ACTION OBJECTIVES FOR CHEMICALS OF CONCERN WARRANTING RESPONSE ACTION ROD Section Decision Summary Remedial Action Objectives Recom mended Toolkit Tip Where appropriate, it may be helpful to use a bullet format to present the remedial action objectives (RAOs) that are established to add- ress all unacceptable current and reasonably anticipated future risks at the site. A bullet format for the RAOs can effectively present qualitative statements. To present the quantitative site-specific cleanup levels that need to be met for each medium in order to achieve the RAOs, it may be useful to include tables to list the chemicals of concern (COCs) in each medium warranting a response action, their respective cleanup levels, and the basis for the cleanup levels. A figure also can be effective to help illustrate the areas within the site where concentrations of COCs exceed cleanup levels and warrant action. • 2 DECISION SUMMARY • 2.7 Remedial Action Objectives The Navy, EPA, and VDEQ concluded that remedial action is necessary to protect public health, welfare, and the environment from actual or threatened releases of hazardous substances in soil, shallow groundwflter, sediment, and surface water at Site 2. Site-specific Remedial Action Objectives (RAOs) are as follows: Waste, soil, and sediment (including sediment pore water): • Prevent direct media contact with human and ecological receptors at concentrations that pose unacceptable risks • Prevent migration of contaminants through surface water runoff and erosion pathways • Prevent or minimize transport of COCs from waste to site media Shallow groundwater (including residual DNAPL): • Reduce contaminant source mass to the maximum extent practicable • Prevent activities that might cause migration of chlorinated VOCs in the Columbia aquifer to the underlying Yorktown aquifer • Prevent chlorinated VOC sediment migration from the shallow groundwater to surface water and • Reduce chlorinated VOC concentrations in shallow groundwater to the maximum extent practicable and prevent exposure until concentrations allow for unlimited use and unrestricted exposure (beneficial use scenario) Surface water: • Minimize degradation of surface water The quantitative cleanup levels that need to be met to achieve the RAOs are presented in Table 2-2 below. TABLE 2-2 COCs and Cleanup Levels ^1 Chemical of Concern Cleanup Level Basis for Cleanup Level ^1 Surface soil (mg/kg) Antimony Lead Vanadium Groundwater (ug/L) 1,1-DCE cis-1,2-DCE Napthalene TCE Sediment (mg/kg) Chromium "average site-wide concentration 26.4 Calculated risk-based value 400* Action Level 72 Background 7 MCL 70 MCL 170 Cacluated risk-based value 5 MCL 53 Background ------- EXHIBIT 11. SUMMARY OF REMEDIAL ALTERNATIVES ROD Section Decision Summary Description of Alternatives Recom mended Toolkit Tip Remedial alternatives dis- cussed in a ROD also may be presented in a summary table identifying the alterna- tives, major components, description (e.g., estimated volume of excavation), costs (capital, operation and main- tenance, present worth, and discount rate), and estimated time frame to achieve reme- dial action objectives (RAOs). Such a table can help show how the alternatives consid- ered would each address the risks at the site, consistent with the basis for action and RAOs. To accurately pres- ent the "no action" alternative, land use controls (LUCs)/ insti- tutional controls (ICs) should not be included, for example. The tables can also include text that presents the com- mon elements and distinguish- ing features that are unique to the alternatives and that may directly affect the implementa- tion, operation, or outcome if selected as the remedy. Refer to Institutional Controls: A Guide to Planning, Imple- menting, Maintaining, and Enforcing Institutional Con- trols at Contaminated Sites (EPA, 2010). A summary table should include appropriate use of terminology for LUCs/ICs, if applicable. Administrative Record Resources Development and Evaluation of Remedial Alternatives 5.1 General Response Actior 52 Identification and Evaluation of Remedial Approaches S3 Development and Evaluation of Remedial Alternatives IF Synthesize Summarize | TABLE 5 - REMEDIAL ALTERNATIVES 1 Alternative No Action No action for contaminated soil with no restriction on activities. Biostimulation and Off- Site Disposal Excavation and stockpiling of contaminated soil foron- site ex-situ treatment followed by backfilling and site restoration. Excavation and Off-Site Disposal contaminated soil followed by off-site disposal, backfilling, and site restoration. Groundwater No Action No action for contaminated groundwater with no restriction on activities. MNA and LUC/ICs Groundwater monitoring to access concentrations of COCs until performance standards have been achieved via natural attenuation Components -Existing soil -Excavation of soil -On-site ex-situ biostimulation followed by off-site disposal -Site restoration -Engineering uontrois -Excavation of soil -Off-site disposal -Site restoration -Engineering Controls ^^^m -Existing groundwater -MNA groundwater monitoring -LUC/ICs Description -No action -Excavation of an estimated 1 ,333 yd3 of soil. On-site material will be evaluated for potential re-use for backfill (it is estimated that only 1/3 of excavated material is contaminated based on existing sample data) -Collection of confirmation samples from the excavation and of the uncontaminated soil for analysis of COCs to verify performance standards are met -Stockpiling of contaminated site soil and placement on a treatment pad with physical controls (fencing and signs) to prevent access and erosion and sediment controls (silt fencing ) to prevent contaminant transport -Mixing stockpiled soil with amendments (e.g. Commercial fertilizer) and bi-weekly aeration to stimulate biological degradation -Periodic sampling of stockpiled soil until performance standards are met followed by off-site disposal -Mixing clean fill and uncontaminated site soil for backfill and site restoration (repaying) -Excavation of an estimated 1 ,333 yd3 of soil. On-site material will be evaluated for potential re-use for backfill (it is estimated that only 1/3 of excavated material is contaminated based on existing sample data) -Collection of confirmation samples from the excavation and of the uncontaminated soil for analysis of COCs to verify performance standards are met -Stockpiling of contaminated site soil with physical controls (signs) to prevent access and erosion and sediment controls (silt fencing) to prevent contaminant transport during waste characterization -Waste characterization testing to classify the contaminated soil for proper off-site disposal -Mixing clean fill and uncontaminated site soil for backfill and site restoration (repaying) ^^M^^^H -No action -Periodic groundwater monitoring (three existing wells and one newly installed well) for natural attenuation indicator parameters and reporting -LUC/ICs to restrict access to the Surficial Aquifer so that the potential exposure pathway to contamination would remain incomplete until performance standards have been achieved -O&M of monitoring wells Cost No cost Capital Cost: $291,600 Annual O&M Cost: $0 Present-Worth Cost: $291,600 Federal Discount Rate: 3.5% Timeframe: 2 years Capital Cost: $229,300 Annual O&M Cost: $0 Present-Worth Cost: $229,300 Federal Discount Rate: 3.5% Timeframe: 1 month ^^^H No cost Capital Cost: $73,400 Annual O&M Cost: $24,900 Present-Worth Cost: $194,300 Federal Discount Rate: 3.5% Timeframe: 5 years ------- EXHIBIT 12. EVALUATING MONITORED NATURAL ATTENUATION AS A REMEDIAL ALTERNATIVE ROD Section Decision Summary Description of Alternatives Recom mended Toolkit Tip A diagram may be a useful tool if Monitored Natural Attenua- tion (MNA) is considered as a potential remedial alternative or component of an alterna- tive for groundwater; the dia- gram can present the lines of evidence contained in the administrative record and dis- cussed in the ROD which sup- port an MNA approach at the site. The diagram also can be an effective tool for depicting a clear and meaningful trend of concentrations, figures of groundwater concentrations over time, and tables of geo- chemical data. Other graphics can help explain the estimated time frame for MNA to achieve cleanup levels, as well as com- parable time frames which could be achieved with active restoration. Tables and diagrams also can be used to portray site-specific data, such as the lines of evi- dence for MNA, and summa- rize the key points discussed in the ROD's evaluation con- tained in the Decision Sum- mary: Description of Alter- natives and Comparative Analysis of Alternatives. VOC Concentrations 900 --. 800 ^ 700 •- 600 •I 500 2 400 | 300 5 200 100 0 u •TCE ^ •cis-l,2-DCE «Sr Vinyl Chloride Geochemical Parameters Temperature (°C) DO (mg/L) pH (SU) ORP (mV) Ferrous Iron (mg/L) Nitrate (mg/L) Nitrite (mg/L) Alkalinity (mg/L) Chloride (mg/L) Sulfate (mg/L) Sulfide (mg/L) TOC (mg/L) Methane (ug/L) Ethane (ug/L) Ethene (ug/L) 18.7 1.2 8.2 31 0.5 Not Detected 1.2 600 57 12 0.8 4.5 24 Not Detected Not Detected 17.4 0.25 7.5 -170 8.2 Not Detected 0.8 1,500 254 1.8 Not Detected 260 780 125 12.8 17.2 0.3 8.1 -123 2.1 Not Detected 0.7 1,400 195 8.4 0.1 48 342 97 5.4 Microbial Analysis (cells/mL) Dehalococcoides Desulfuromonas Dehalobacter Not Detected Not Detected 2.81 350,000 23.6 45.1 5,000 1.54 6.45 TCE Concentrations Over Time > Monitoring \Afell Locations Groundwater Flow Site Boundary 3 Monitoring \Afell Locations Groundwater Flow Site Boundary Lines of evidence for MNA: 1. Historical groundwater and/or soil chemistry data that demonstrate a clear and meaning- ful trend of decreasing contaminant mass and/or concentration over time at appropriate monitoring or sampling points. (In the case of a groundwater plume, decreasing concentrations should not be solely the result of plume migra- tion. In the case of inorganic contaminants, the primary attenuating mechanism should also be understood.) 2. Hydrogeologic and geochemical data that can be used to demonstrate indirectly the type(s) of natural attenuation processes active at the site, and the rate at which such processes will reduce contaminant concentrations to required levels. For example, characterization data may be used to quantify the rates of contaminant sorption, dilution, or volatilization, or to demon- strate and quantify the rates of biological deg- radation processes occurring at the site. 3. Data from field or microcosm studies (conduct- ed in or with actual contaminated site medium) which directly demonstrate the occurrence of a particular natural attenuation process at the site and its ability to degrade the contaminants of concern (typically used to demonstrate bio- logical degradation processes only). Use of Monitored Natural Attenuation at Superfund, RCRA Corrective Action, and Underground Storage Tank Sites (EPA, 1999) Performance monitoring to evaluate biodegradation over time should be included as part of an MNA alternative. ------- EXHIBIT 13. COMPARATIVE ANALYSIS OF ALTERNATIVES ROD Section Decision Summary Comparative Analysis of Alternatives Recom mended Toolkit Tip Various table formats using summary text can be effec- tive in complementing the ROD's detailed discussion of how each alterna- tive compares with the other alternatives and with respect to the National Oil and Hazardous Sub- stances Pollution Contin- gency Plan (NCP) nine criteria. Tables can help identify the distinguishing element or factor that favors one alternative above the others and that supports the rationale for selection of the remedy explained in the ROD. A graphic "consumer report" style table may be used to present the rela- tive ranking in support of the ROD'S text. The NCP's two thresh- old criteria must be met for all alternatives except "no action". If contingency remedies are a compo- nent of a remedial alt- ernative, be sure to evaluate them with respect to the NCP criteria. Refer to "Guide to Preparing Superfund Pro- posed Plans, Record of Decisions, or Other Rem- edy Selection Decision Doc- uments" (OSWER 9200.1- 23P, July 1,1999), Highlight 8-8, p. 8.10. Administrative Record Resources Synthesize Summarize Protection of human health and the environment Compliance with ARARs Primary Balancing Criteria Long-term effectiveness and permanence Reduction in toxicity, mobility, or volume through treatment 00 • • 00 • $1.1 M S2.5M S1.9M S1.9M Short-term effectiveness Implementability Present Cost Modifying Criteria State Acceptance Community Acceptance Ranking: • High O Moderate O Low Rankings are provided as qualitative descriptions of the relative compliance of each alternative with the criteria. NC = No significant comments were received from Community Members Yellow shading indicates selected remedy. ------- EXHIBIT 14. DESCRIPTION OF SELECTED REMEDY ROD Section Decision Summary Selected Remedy Recom mended Toolkit Tip A figure typically is an effective way to help describe the Selected Remedy discussion in the ROD; a figure can be use- ful to illustrate the remedy components that address all chemicals of concern and medium requiring action. For example, the figures in this exhibit show the groundwater treatment area/soil removal area, pro- posed injections points for treatment, performance and long-term monitor- ing locations as well as the estimated aquifer use control boundary that will be in-place until ground- water cleanup levels are achieved. Legend ® Existing Monitoring Wells • Estimated Injection Points Q Estimated RA Monitoring Well' ® Estimated LTM Wells 5 Estimated Boundary Aquifer U Groundwater Flow ------- EXHIBIT 15. EXPECTED OUTCOMES OF THE SELECTED REMEDY ROD Section Decision Summary Selected Remedy Recom mended Toolkit Tip A summary table can be a useful tool to supple- ment ROD text by high- lighting how the key com- ponents of the Selected Remedy are designed to mitigate risk to achieve remedial action objectives consistent with current and potential future land and resource uses. 2.9.3 Expected Outcomes of the Selected Remedy Current industrial land uses are expected to continue at Site 73 and there are no other planned land uses in the foreseeable future, or for development of adjacent lands. Cleanup levels for the Selected Remedy are based on unlimited use and unrestricted exposure. Exposure will be controlled through land use controls/industrial controls (LUCs/ICs) until chemicals of concern (COCs) in groundwater and soil are reduced to the cleanup levels. Table 2-5 summarizes the unacceptable risk (media, pathway, receptor), the remedial action objectives (RAOs) identified to address the risk, the remedy component intended to achieve the RAO, the metric that measures the remedial action progress, and the expected outcome that the remedy will achieve. TABLE 2-5 Expected Outcomes of the Selected Remedy Risk IngestionofVOCS in groundwater under potable use scenario Direct exposure to arsenic in soil under residential use scenario and leaching potential to groundwater Transport ofVOCs in groundwater to surface water Remedial Action Objective Restore groundwater quality based on the classification of the aquifer as a potential source of drinking water and to prevent human ingestion of water containing chemicals of NCGWQS or MCL standards, whichever is more stringent until cleanup levels have been obtained. Prevent future residential exposure to arsenic-contaminated soils above the NC HWS SSL and minimize transport to groundwater. Minimize migration of chemicals of concern in groundwater to surface water. Remedy Component Air sparge system LTM for MNA LUCs/ICs LUCs/ICs ERD biobarrier LTM LUCs/ICs Metric Operate system for up to 5 years or until groundwater cleanup levels within the radius of influence are met, whichever is the shortest period. Implement until each groundwater chemical of concern is at or below its respective cleanup level for four consecutive monitoring events. Maintain LUCs/ICs until chemicals of concern in the soil are at such levels that allow for unlimited use and unrestricted exposure. Maintain until chemicals of concern in groundwater meet cleanup levels Implement until each groundwater chemical of concern is at or below its respective cleanup level for four consecutive monitoring events. Expected Outcomes Achieve exposure Maintain industrial use Minimize migration of chemicals of concern in groundwater to surface water The air sparge system will be operated for up to 5 years or until the cleanup levels within the radius of influence were met, whichever is the shortest period. System effectiveness will be evaluated annually by comparison of current concentrations of COCs in treatment area monitoring wells to pretreatment concentrations and the cleanup levels. The enhanced reductive dechlorination (ERD) biobarrier wall will be maintained until groundwater COCs concentrations have met the cleanup levels. In accordance with LUC/IC objectives, groundwater use will be restricted to monitoring or remedial purposes. Long-term monitoring (LTM) for Monitored Natural Attenuation (MNA) will be conducted until each COC in groundwater is at or below its respective cleanup level for four con- secutive monitoring events. The Navy and Marine Corps, in partnership with USEPA and the State, will evaluate the discontinuation of monitoring of individual COCs that have met the cleanup levels after four rounds based on site conditions. The results of LTM will be documented in an annual monitoring report. When all COCs have achieved their cleanup levels for four consecutive sampling events, site closure will be initiated. Once RAOs for this groundwater action have been achieved, the Site 73 area is expected to be suitable for unlimited use and unrestricted exposure for groundwater. Therefore, the Navy, USEPA, and NCDENR may agree for the groundwater LUC/IC component of the Selected Remedy to be terminated at site closeout. LUCs/ICs, restricting any potential future residential exposure to Impacted soils, will be maintained until the concentration of COCs in the soil are at such levels that allow for unrestricted use and unlimited exposure. ------- EXHIBIT 16. OPTIONAL REFERENCE CD Administrative Record File Recom mended Toolkit Tip A hard copy ROD is the official ROD and should be placed in the Administrative Record. An optional CD ref- erence tool can be included as a supplemental tool in order to provide the reader with immediate access to Administrative Record files referenced within the ROD. A detailed reference table, highlighting the key words identified in the ROD text, should be provided. Prior to developing a reference CD, stakeholder input and com- munity involvement should be considered. Hyperlinked Administrative Record Information em Reference Phrase in ROD Location in ROD Site 12 is the crash-crew Section 2.1 training area hydrogeologic setting Section 2.2 Identification of Referenced Document Available in the Administrative Record1 Final Remedial Investigation Report, Operable Unit 6, Site 12, Crash Crew Training Area, MCAS Cherry Point, North Carolina. Attachment 2, Section 2.2, Pages 2-1 through 2-3. CH2M HILL, December 2005. Final Remedial Investigation Report, Operable Unit 6, Site 12, Crash Crew Training Area, MCAS Cherry Point, North Carolina. Section 4.3.4.1, Pages 4-10 through 4-13. CH2M HILL. 4.3.4.1 Site 12 Geology and Hydrogeology The USGS has conducted several studies of the hydrogeology at MCAS Cherry Point. A description of MCAS Cherry Point geology and hydrogcology as described by the.- USGS is presented to provide an overview of available information and characteristics of the hydrostratigraphic units at the MCAS. While developing a quasi three-dimensional finite-difference ground water-flow model and while analyzing the hydrogeologic framework of MCAS Cherry Point, the USGS evaluated geophysical and litliologic well log data from 30 wells and water-level data from oil test wells, water supply wells, and observation wells. The subsurface materials evaluated by the USGS investigations and supported by site borings are separated into the following aquifers and respective confining units: Surficial Aquifer, Yorktown Aquifer, Pungo River Aquifer, upper Castle Hayne Aquifer, and lower Castle Haync Aquifer. Deeper aquifers are not addressed in this site-specific discussion because the depth and separation of these aquifers from contaminant sources by a series of confining units, as well as the brackish water quality of the deeper aquifers, preclude the potential for significant impacts to these deeper aquifers. Other Optional Electronic Enhancements The public information repository is located at the library, Havelock, NC 28532, Phone 252-447-7509 remedy section process will be available the IR Program website ROD with Optional Reference CD ------- United States Office of Solid Waste OSWER 9355.6-10 Environmental Protection and Emergency Response September 2011 Agency ° ' r r ------- |