8. FIO-GFI-EastElliot_RI_FS.pdf

U.S. ARMY CORPS OF ENGINEERS

Los Angeles District

REMEDIAL INVESTIGATION/

FEASIBILITY STUDY REPORT

FORMER CAMP ELLIOTT, EAST ELLIOTT

FUDS MMRP Project J09CA006703

MRS 01 - Range Complex (Project 03) Contract No. W912PL-12-D-0005

Task Order 0006

FINAL

FEBRUARY 2018

l1pmmama Text Box

1200C PERM

J09CA006703_03.10_0501_a

(Intentionally blank)

APPROVALS

By their signatures, the undersigned attest to the completeness of this Remedial

Investigation/Feasibility Study Report, as guided by current methodologies and regulations;

direction or input from United States Army Corps of Engineers, regulators, and stakeholders;

and that it is in conformance to the contractual requirements.

Andy Biaggi Quality Control Manager

Date

Mary Franquemont Project Manager

Date 28 February 2018

28 February 2018

Final Report East Elliott Remedial Investigation/Feasibility Study

February 2018 i Contract No. W912PL-12-D-0005

TABLE OF CONTENTS

SECTION PAGE

APPENDICES .......................................................................................................................... vi TABLES ................................................................................................................................... vii DIAGRAMS ........................................................................................................................... viii FIGURES .................................................................................................................................. ix

ACRONYMS AND ABBREVIATIONS ................................................................................. xi DEFINITIONS OF MUNITIONS RESPONSE TERMINOLOGY .........................................xv

1.0 EXECUTIVE SUMMARY ......................................................................................... 1-1

1.1 Remedial Investigation............................................................................................ 1-2

MEC Characterization ......................................................................................... 1-2

MC Characterization ........................................................................................... 1-9

1.2 Feasibility Study ................................................................................................... 1-10

2.0 INTRODUCTION ...................................................................................................... 2-1

2.1 Purpose .................................................................................................................... 2-1

2.2 MRS Boundary Modifications and Sub-Area Delineations .................................... 2-2

2.3 Property Description ............................................................................................... 2-7

Site Description ................................................................................................... 2-7

2.4 Cultural and Archaeological Resources ................................................................ 2-20

Paleo-Indian Period ........................................................................................... 2-20

Archaic Period ................................................................................................... 2-20

Late Prehistoric Period ...................................................................................... 2-21

Previous Research ............................................................................................. 2-21

2.5 Historical Information ........................................................................................... 2-22

World War I Era ................................................................................................ 2-23

World War II Era .............................................................................................. 2-23

Post-World War II Era ...................................................................................... 2-26

2.6 Previous Investigations and Removal Actions ...................................................... 2-27

1984 Clearance Activities ................................................................................. 2-27

1994 Clearance Activities ................................................................................. 2-27

1996 Ordnance and Explosives Sampling......................................................... 2-28

1998-1999 Construction Support and Time Critical Removal Action.............. 2-31

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1999 Engineering Evaluation/Cost Analysis .................................................... 2-31

2003 Equestrian Staging Area Construction Support ....................................... 2-32

2004 Sycamore Landfill Construction Support................................................. 2-32

2005 Munitions Constituents Sampling ............................................................ 2-32

2007 Surface Removal Action – Mission Trails Regional Park ....................... 2-33

2.7 Problem Identification ........................................................................................... 2-33

Known Explosive Hazards ................................................................................ 2-33

Biological and Cultural/Historical Resources ................................................... 2-33

Potential Human and Ecological Receptors ...................................................... 2-34

3.0 PROJECT REMEDIAL RESPONSE OBJECTIVES ................................................. 3-1

3.1 Conceptual Site Model and Project Approach ........................................................ 3-2

Conceptual Site Exposure Model ........................................................................ 3-2

Project Approach ................................................................................................. 3-3

3.2 Preliminary Remediation Goals and Remedial Action Objectives ......................... 3-3

3.3 Preliminary Identification of ARARs and To Be Considered Information ............ 3-4

3.4 Summary of Institutional Analysis ....................................................................... 3-11

California Department of Toxic Substances Control ........................................ 3-12

Landowners ....................................................................................................... 3-12

3.5 Data Needs and Data Quality Objectives .............................................................. 3-13

Data Needs ........................................................................................................ 3-13

Data Quality Objectives .................................................................................... 3-13

4.0 RI CHARACTERIZATION OF MEC AND MC ......................................................... 4-1

4.1 MEC Characterization ............................................................................................. 4-1

Identification of Investigation Areas ................................................................... 4-1

RI MEC Characterization Preparation Tasks ...................................................... 4-2

DGM Investigation ............................................................................................. 4-2

DGM Data Processing and Interpretation ........................................................... 4-6

Measurement Quality Objectives and Quality Control Tests ........................... 4-25

4.2 MC Characterization ............................................................................................. 4-31

Background Metals Survey ............................................................................... 4-31

Sampling Locations for MRS 01....................................................................... 4-31

Analytical Laboratory and Analyses ................................................................. 4-32

Preliminary Screening Values ........................................................................... 4-32

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4.3 Departures from Planning Documents .................................................................. 4-33

5.0 RI RESULTS AND REVISED CSEM ....................................................................... 5-1

5.1 RI Field Schedule .................................................................................................... 5-1

5.2 MEC and MD Characterization for MRS 01a ........................................................ 5-1

RI Results for MRS 01a ...................................................................................... 5-1

MRS 01a Previous Investigations ....................................................................... 5-4

Munitions Data Analysis for MRS 01a ............................................................... 5-5

5.3 MEC and MD Characterization for MRS 01b ........................................................ 5-6

RI Results for MRS 01b ...................................................................................... 5-6

MRS 01b Previous Investigations ....................................................................... 5-7

Munitions Data Analysis for MRS 01b ............................................................... 5-9

5.4 MEC and MD Characterization for MRS 01c ...................................................... 5-10

RI Results for MRS 01c .................................................................................... 5-10

MRS 01c Previous Investigations ..................................................................... 5-12

Munitions Data Analysis for MRS 01c ............................................................. 5-13

5.5 MEC and MD Characterization for MRS 01d ...................................................... 5-13

RI Results for MRS 01d .................................................................................... 5-14

MRS 01d Previous Investigations ..................................................................... 5-16

Munitions Data Analysis for MRS 01d ............................................................. 5-18

5.6 MEC and MD Characterization for MRS 01e ...................................................... 5-19

RI Results for MRS 01e .................................................................................... 5-19

MRS 01e Previous Investigations ..................................................................... 5-19

Munitions Data Analysis for MRS 01e ............................................................. 5-19

5.7 MEC and MD Characterization for MRS 01f ....................................................... 5-20

RI Results for MRS 01f .................................................................................... 5-20

MRS 01f Previous Investigations ..................................................................... 5-20

Munitions Data Analysis for MRS 01f ............................................................. 5-21

5.8 MC Sampling and Results ..................................................................................... 5-21

5.9 Status of DQOs ..................................................................................................... 5-36

DQOs for MEC Investigation ........................................................................... 5-36

DQOs for MC Sampling ................................................................................... 5-37

5.10 Revised Conceptual Site Exposure Models .......................................................... 5-37

MEC Exposure Pathways .............................................................................. 5-38

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MC Exposure Pathways ................................................................................ 5-41

6.0 CONTAMINANT FATE AND TRANSPORT FOR MEC AND MC ....................... 6-1

6.1 Potential MEC Mechanisms .................................................................................... 6-1

Potential Sources ................................................................................................. 6-1

Fate and Transport Pathways .............................................................................. 6-1

6.2 Potential MC Mechanisms ...................................................................................... 6-2

Potential Sources and Release Mechanisms ....................................................... 6-2

Fate and Transport Pathways .............................................................................. 6-2

7.0 HAZARD ASSESSMENT FOR MEC and RISK ASSESSMENTS FOR MC ......... 7-1

7.1 MEC Hazard Assessment ........................................................................................ 7-1

Background ......................................................................................................... 7-1

Defining the Areas to be Assessed ...................................................................... 7-3

Overview of MEC HA Input Factors .................................................................. 7-3

Overview of MEC HA Output Factors ............................................................... 7-5

MEC HA Characterization for East Elliott MRS Sub-Areas .............................. 7-6

Baseline MEC HA Characterization for East Elliott MRS Sub-Areas ............... 7-6

7.2 MC Risk Assessment ............................................................................................ 7-13

8.0 SUMMARY OF RI RESULTS ................................................................................... 8-1

8.1 Summary of Nature and Extent of MEC ................................................................. 8-1

MRS 01a ............................................................................................................. 8-1

MRS 01b ............................................................................................................. 8-3

MRS 01c ............................................................................................................. 8-4

MRS 01d ............................................................................................................. 8-6

MRS 01e ............................................................................................................. 8-7

MRS 01f .............................................................................................................. 8-8

MRS 01g ............................................................................................................. 8-9

8.2 Summary of Nature and Extent of MC ................................................................... 8-9

8.3 Areas to be Evaluated During Feasibility Study ................................................... 8-10

9.0 IDENTIFICATION AND SCREENING OF TECHNOLOGIES .............................. 9-1

9.1 Remedial Action Objective ..................................................................................... 9-1

9.2 General Response Actions ...................................................................................... 9-3

9.3 Identification and Screening of Remedial Technologies for MEC ......................... 9-4

Detection Technologies ....................................................................................... 9-4

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Removal Technologies ........................................................................................ 9-6

Disposal Technologies ........................................................................................ 9-6

10.0 DEVELOPMENT AND SCREENING OF ALTERNATIVES ............................... 10-1

10.1 Alternative Descriptions........................................................................................ 10-3

Alternative 1: No Action ............................................................................... 10-3

Alternative 2: ICs to Protect Current and Future Site Users ......................... 10-4

Alternative 3: MEC Removal from the Surface with ICs to Protect Current and Future Site Users ........................................................................................................... 10-5

Alternative 4: DGM and Surface/Subsurface Removal of MEC to Depth of 36 inches with ICs to Protect Current and Future Site Users (implemented for the entire MRS sub-area) .............................................................................................................. 10-7

Alternative 5: DGM with Advanced Classification Sensor and Surface/Subsurface Removal of MEC to Depth of 36 inches with ICs to Protect Current and Future Site Users (implemented for MRS 01a sub-area only) ............................... 10-9

Alternative 6: DGM and Surface/Subsurface Removal of MEC to Depth of 36 inches with ICs to Protect Current and Future Site Users (implemented for delineated response areas) ............................................................................................................ 10-11

Alternative 7: Excavation, Sifting, and Restoration.................................... 10-12

10.2 Application of Screening Criteria by Alternatives .............................................. 10-13

11.0 DETAILED ANALYSIS OF ALTERNATIVES ..................................................... 11-1

11.1 Evaluation Criteria ................................................................................................ 11-2

Threshold Factors .......................................................................................... 11-2

Balancing Factors .......................................................................................... 11-3

Modifying Factors ......................................................................................... 11-4

11.2 Individual Analysis of Alternatives ...................................................................... 11-4

Feasibility Study for MRS 01a ...................................................................... 11-5

Feasibility Study for MRS 01b ................................................................... 11-23

Feasibility Study for MRS 01c .................................................................... 11-41

Feasibility Study for MRS 01d ................................................................... 11-63

Feasibility Study for MRS 01f .................................................................... 11-81

11.3 Comparative Analysis of Alternatives .............................................................. 11-100

Evaluation of Alternatives for MRS 01a ................................................... 11-101

Evaluation of Alternatives for MRS 01b .................................................. 11-105

Evaluation of Alternatives for MRS 01c ................................................... 11-109

Evaluation of Alternatives for MRS 01d .................................................. 11-113

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Evaluation of Alternatives for MRS 01f ................................................... 11-118

12.0 SUMMARY OF FEASIBILITY STUDY ................................................................ 12-1

12.1 Alternatives ........................................................................................................... 12-1

12.2 Evaluation ............................................................................................................. 12-2

12.3 Summary of Analysis by MRS Sub-area .............................................................. 12-2

Summary of Analysis - MRS 01a ................................................................. 12-2

Summary of Analysis – MRS 01b ................................................................ 12-3

Summary of Analysis – MRS 01c ................................................................. 12-3

Summary of Analysis – MRS 01d ................................................................ 12-4

Summary of Analysis – MRS 01f ................................................................. 12-4

12.4 Costs ...................................................................................................................... 12-4

12.5 Conclusions ........................................................................................................... 12-6

13.0 REFERENCES .......................................................................................................... 13-1

APPENDICES

Appendix A Performance Work Statement Appendix B Biological Resources Report – Excerpt from Final RI Work Plan Appendix C Institutional Analysis Report Appendix D Conceptual Site Exposure Models Appendix E Site-Specific Munitions and Explosives of Concern Appendix F Site Figures Appendix G Munitions and Explosives of Concern Hazard Assessment Worksheets Appendix H Remedial Action Alternative Cost Estimate Worksheets (Digital format only) Appendix I Analytical Data Packages (Digital format only) Appendix J Data Verification Reports Appendix K Draft RI Field Operations Completion Report with Geophysical Data Report Appendix L Geographic Information System Submittal (Digital format only) Appendix M Documentation of Stakeholder Concurrence

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TABLES

Table 1-1 Overview of Evaluated Alternatives for MRSs ................................................ 1-13

Table 2-1 RI Study Area MRS 01 Sub-Areas ..................................................................... 2-5

Table 2-2 MRS Sub-area Acreage Greater Than 30% Grade ............................................. 2-8

Table 2-3 T&E Species with Potential to Occur at MRS 01 ............................................. 2-16

Table 2-4 MRS 01 Land Uses ........................................................................................... 2-19

Table 2-5 1994 MRS 01 Grid Sampling ............................................................................ 2-28

Table 2-6 Summary Data for 1996 GridStat Investigation................................................ 2-29

Table 2-7 MRS 01 Sub-Areas Human Receptors .............................................................. 2-34

Table 3-1 ARARs, Former Camp Elliott, East Elliott FUDS .............................................. 3-7

Table 4-1 VSP Transect Analysis ........................................................................................ 4-5

Table 4-2 Critical Density Point Analysis ........................................................................... 4-8

Table 4-3 UXO Estimator Results ..................................................................................... 4-18

Table 4-4 UXO Estimator Results for MRS 01b ............................................................... 4-19

Table 4-5 UXO Estimator Results for MRS 01c ............................................................... 4-20

Table 4-6 UXO Estimator Results for MRS 01d ............................................................... 4-20

Table 4-7 UXO Estimator Results for MRS 01a and MRS 01d ........................................ 4-24

Table 4-8 Static Results Summary for Towed Array System ........................................... 4-26

Table 4-9 Static Results Summary for Transect System ................................................... 4-27

Table 4-10 IVS Offset Summary ..................................................................................... 4-28

Table 4-11 IVS Response Summary ............................................................................... 4-29

Table 5-1 Remedial Investigation Field Operations Schedule Summary............................ 5-1

Table 5-2 Geophysical Survey Results for MRS 01a .......................................................... 5-2

Table 5-3 Geophysical Survey Results for MRS 01c ........................................................ 5-11

Table 5-4 Geophysical Survey Results for MRS 01d........................................................ 5-14

Table 5-5 MC Investigatory and Background Soil Sample Analytical Results ................ 5-25

Table 5-6 Summary Statistics for Background Samples Metals Concentrations .............. 5-29

Table 5-7 Summary Statistics for Investigatory Site Samples Metals Concentrations ..... 5-30

Table 5-8 Background Comparisons Results for Metals Concentrations ......................... 5-35

Table 5-9 Revised CSEM Summary for East Elliott MRS Sub-areas ............................... 5-43

Table 7-1 MEC Severity ...................................................................................................... 7-4

Table 7-2 Site Accessibility ................................................................................................. 7-4

Table 7-3 Fuze Sensitivities ................................................................................................ 7-5

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Table 7-4 Summary of MEC HA Results East Elliott MRS Sub-areas .............................. 7-7

Table 8-1 MRS 01 Sub-Areas ........................................................................................... 8-11

Table 9-1 Potential MEC Summary for MRS 01 ................................................................ 9-2

Table 10-1 Summary of RAAs ........................................................................................ 10-2

Table 11-1 Alternative Analysis and Scoring for RAAs at MRS 01a ......................... 11-123

Table 11-2 Alternative Analysis and Scoring for RAAs at MRS 01b ........................ 11-124

Table 11-3 Alternative Analysis and Scoring for RAAs at MRS 01c ......................... 11-125

Table 11-4 Alternative Analysis and Scoring for RAAs at MRS 01d ........................ 11-126

Table 11-5 Alternative Analysis and Scoring for RAAs at MRS 01f ......................... 11-127

Table 11-6 Overview of Evaluated Alternatives for East Elliott MRS Sub-areas ...... 11-128

Table 12-1 Summary of Cost Estimates by MRS Sub-areas for RAAs .......................... 12-6

DIAGRAMS

Diagram 4-1 VSP Flagging Routine Results .................................................................... 4-9

Diagram 4-2 Hypothetical Site Histograms ................................................................... 4-11

Diagram 4-3 Histogram of Kriging Results ................................................................... 4-12

Diagram 4-4 Delineated Areas based on 400 Anomalies per Acre ................................ 4-13

Diagram 4-5 Composite Box Plot for Delineated Areas at 400 Anomalies per Acre .... 4-14

Diagram 4-6 Delineated Areas Based on 180 Anomalies per Acre ............................... 4-16

Diagram 4-7 Composite Box Plot for Delineated Areas at 180 Anomalies per Acre .... 4-17

Diagram 4-8 ArcGIS Analysis Results – All Anomalies ............................................... 4-22

Diagram 4-9 ArcGIS Analysis Results – Anomalies per Acre ...................................... 4-22

Diagram 4-10 ArcGIS Analysis Results – TCRA UXO/Acre ........................................ 4-23

Diagram 4-11 ArcGIS Analysis Results – Combined UXO Estimate and TCRA UXO . 4-24

Diagram 5-1 Histogram of MRS 01a VSP Analysis ........................................................ 5-3

Diagram 5-2 Histogram of MRS 01b VSP Analysis ........................................................ 5-7

Diagram 5-3 Histogram of MRS 01c VSP Analysis ...................................................... 5-12

Diagram 5-4 Histogram of MRS 01d VSP Analysis ...................................................... 5-16

Diagram 5-5 Boxplots for Metals Data by Site vs Background and by Soil Type ........ 5-32

February 2018 ix Contract No. W912PL-12-D-0005

FIGURES

Figure 1-1 Site Location Figure 1-2 Site Layout Figure 1-3 MRS 01 Site Boundary Modification Figure 2-1 MRS Sub-areas Figure 2-2 Site Topography Figure 2-3 Site Geology Figure 2-4 Distribution of Threatened and Endangered Species and Habitats Figure 2-5 Future Land Use Figure 2-6 Historical Ranges Figure 2-7 Summary of Previous Investigations Figure 2-8 Previous Investigation Sectors Figure 4-1 Previous Investigations Based UXO Densities Figure 5-1 DGM Coverage Figure 5-2 MRS 01a Geophysical Anomaly Density Figure 5-3 MRS 01a Previous Investigation Results Figure 5-4 MRS 01b Previous Investigation Results Figure 5-4a MRS 01b Areas Not Previously Investigated Figure 5-5 MRS 01c and MRS 01d Geophysical Anomaly Density Figure 5-6 MRS 01c Previous Investigation Results Figure 5-7 MRS 01d Previous Investigation Results Figure 5-8 MRS 01f Previous Investigation Results Figure 5-9 RI Sample Locations with Munitions Related Finds and Anomaly Density Figure 5-10 RI Sample Locations with Geologic Formation Types

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ACRONYMS AND ABBREVIATIONS

oF degrees Fahrenheit % Percent § Section 95%UCL 95% upper confidence limit of the mean AA Anti-aircraft Accord Accord Engineering, Inc.

amsl above mean sea level AP Armor-piercing APC Armor-piercing, Capped AP-T Armor-piercing Tracer ARAR Applicable or Relevant and Appropriate Requirement ASR Archives Search Report bgs below ground surface BIP Blow(n)-in-Place Bristol Bristol Environmental Remediation Services, LLC BSP Blind Seeding Program Ch Channel CHHSL California Human Health Screening Level CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations CHE Chemical Warfare Materiel Hazard Evaluation COPC Contaminant of Potential Concern CSEM Conceptual Site Exposure Model CWM Chemical Warfare Materiel DERP Defense Environmental Restoration Program DGM Digital Geophysical Mapping DID Data Item Description DMM Discarded Military Munitions DoD U.S. Department of Defense DoD QSM Department of Defense Quality Systems Manual DQO Data Quality Objective DTSC California Department of Toxic Substance Control DZ Debris Zone Eco-SSL Ecological Soil Screening Level

February 2018 xii Contract No. W912PL-12-D-0005

EE/CA Engineering Evaluation/Cost Analysis EHE Explosive Hazard Evaluation EM Engineer Manual EM61 Geonics EM61-MK2A EOD Explosive Ordnance Disposal EP Engineer Pamphlet ER Engineer Regulation ESA Endangered Species Act ESTCP Environmental Security Technology Certification Program FD Field Duplicate FS Feasibility Study

ft. Foot/Feet FUDS Formerly Used Defense Site GIS Geographic Information System GPS Global Positioning System GSA General Services Administration GSV Geophysical System Verification HA Hazard Assessment HE High Explosive HFD Hazardous Fragment Distance HHE Health Hazard Evaluation HMX Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine HQ Hazard Quotient IC Institutional Control InDepth InDepth Corporation INPR Inventory Project Report ISO Industry Standard Object ITRC Interstate Technology and Regulatory Council IVS Instrument Verification Strip LCS Laboratory Control Spike LOQ Limit of Quantitation LTM Long Term Monitoring MBTA Migratory Bird Treaty Act MC Munitions Constituent MCAS Marine Corps Air Station MD Munitions Debris

February 2018 xiii Contract No. W912PL-12-D-0005

MEC Munitions and Explosives of Concern MEC HA Munitions and Explosives of Concern Hazard Assessment MFD-H maximum fragmentation distance - horizontal mg/kg milligrams per kilogram MGFD Munitions with the Greatest Fragmentation Distance mm millimeter MMRP Military Munitions Response Program mph miles per hour MPPEH Material Potentially Presenting an Explosive Hazard MQO Measured Quality Objective MRS Munitions Response Site MS/MSD Matrix Spike/Matrix Spike Duplicate MTRP Mission Trails Regional Park mV millivolt MVS U.S. Army Corps of Engineers, St. Louis District N/A Not Applicable NA Not Analyzed NAD North American Datum NAS Naval Air Station nc noncarcinogenic NCP National Contingency Plan Neptune Neptune and Company, Inc.

OEW Ordnance and Explosive Waste PD Point Detonating PETN Pentaerythritol tetranitrate PRG Preliminary Remediation Goal PWS Performance Work Statement QA Quality Assurance QC Quality Control RAA Remedial Action Alternative RACER Remedial Action Cost Engineering and Requirement RAO Remedial Action Objective RDX Hexahydro-1,3,5-trinitro-1,3,5-triazine RI Remedial Investigation ROE Right of Entry RSL Regional Screening Level

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RTK Real Time Kinematic SDG&E San Diego Gas and Electric SLERA Screening Level Ecological Risk Assessment SR State Road SSL Soil Screening Level STP Shovel Test Pit T&E Threatened and Endangered TBC To Be Considered TCRA Time Critical Removal Action TDEM Time Domain Electromagnetic Tetryl Methyl-2,4,6-trinitrophenylnitramine TOI Target of Interest TPP Technical Project Planning TRV Toxicity Reference Value UFP-QAPP Uniform Federal Policy for Quality Assurance Project Plans USACE U.S. Army Corps of Engineers USC U.S. Code USEPA U.S. Environmental Protection Agency USFWS U.S. Fish and Wildlife Service USMC U.S. Marine Corps USN U.S. Navy UU/UE Unlimited Use/Unrestricted Exposure UXO Unexploded Ordnance VSP Visual Sample Plan WERS Worldwide Environmental Remediation Services WP White Phosphorus WWI World War I WWII World War II

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DEFINITIONS OF MUNITIONS RESPONSE TERMINOLOGY

Discarded Military Munitions (DMM)—Military munitions that have been abandoned without proper disposal or removed from storage in a military magazine or other storage area for the purpose of disposal. The term does not include unexploded ordnance (UXO), military munitions that are being held for future use or planned disposal, or military munitions that have been properly disposed consistent with applicable environmental laws and regulations

(10 United States Code [USC] Section (§) 2710(e)(2)).

High Explosives—High explosives are materials that detonate (i.e., the front of the chemical reaction moves faster through the material than the speed of sound). Munitions Constituents

(for example, TNT, RDX), as defined in 10 USC 2710(e)(3), posing an explosive hazard can be defined as high explosive or low explosive (i.e., low explosives exhibit deflagration, which is a rapid high energy release combustion event that propagates through a gas or an explosive material at subsonic speeds, driven by the transfer of heat).

Material Potentially Presenting an Explosive Hazard (MPPEH)—Material potentially containing explosives or munitions, or potentially contaminated with a high enough concentration of explosives such that the material presents an explosive hazard. Such material includes, but may not be limited to: munitions components; munitions containers and packaging materiel; munitions debris (e.g., scrap metals, plastics) and other material remaining after munitions use or demilitarization; equipment and munitions debris related to research, development, testing, and evaluation; range-related debris (e.g., targets); buildings;

structures; and utility systems that may contain residues resulting from munitions-related activities (e.g., munitions production or demilitarization). Excluded from MPPEH are munitions within Department of Defense’s (DoD) established munitions management system and other hazardous items that may present explosion hazards (e.g., gasoline cans, compressed gas cylinders) that are not munitions and are not intended for use as munitions.

Military Munitions—Military munitions means all ammunition products and components produced for or used by the armed forces for national defense and security, including ammunition products or components under the control of the DoD, the Coast Guard, the

Department of Energy, and the National Guard. The term includes confined gaseous, liquid, February 2018 xvi Contract No. W912PL-12-D-0005 and solid propellants, explosives, pyrotechnics, chemical and riot control agents, smokes, and incendiaries, including bulk explosives and chemical warfare agents, chemical munitions, rockets, guided and ballistic missiles, bombs, warheads, mortar rounds, artillery ammunition, small arms ammunition, grenades, mines torpedoes, depth charges, cluster munitions and dispensers, demolition charges, and devices and components thereof. The term does not include wholly inert items, improvised explosive devices, and nuclear weapons, nuclear devices, and nuclear components, except that the term does include non-nuclear components of nuclear devices that are managed under the nuclear weapons program of the Department of

Energy after all required sanitization operations under the Atomic Energy Act of 1954 (42

USC §2011 et seq.) have been completed (10 USC §2710(e)(3)(A) and (B)).

Munitions Constituents (MC)—Any materials originating from UXO, discarded military munitions, or other military munitions, including explosive and non-explosive materials, and emission, degradation, or breakdown elements of such ordnance or munitions (10 USC §2710

(e)(4)).

Munitions Debris (MD)—Remnants of munitions (e.g., fragments, penetrators, projectiles, shell casings, links, fins) remaining after munitions use, demilitarization, or disposal.

Munitions and Explosives of Concern (MEC)—This term, which distinguishes specific categories of military munitions that may pose unique explosives safety risks, means:

(a) UXO, as defined in 10 USC §2710 (e)(9); (b) DMM, as defined in 10 USC §2710 (e)(2);

or (c) explosive munitions constituents (e.g., 2,4,6-Trinitrotoluene [TNT], Hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX]) present in high enough concentrations to pose an explosive hazard.

Munitions Response—Response actions, including investigation, removal, and remedial actions to address the explosives safety, human health, or environmental risks presented by

UXO or DMM, or by MC.

Munitions Response Area (MRA)—Any area on a defense site that is known or suspected to contain UXO, DMM, or MC. Examples include former ranges and munitions burial areas. A munitions response area is comprised of one or more munitions response sites.

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Munitions Response Site (MRS)—A discrete location within an MRA that is known to require a munitions response.

Unexploded Ordnance (UXO)—Military munitions that: (a) have been primed, fuzed, armed, or otherwise prepared for action; (b) have been fired, dropped, launched, projected, or placed in such a manner as to constitute a hazard to operations, installations, personnel, or material; and (c) remain unexploded either by malfunction, design, or any other cause (USC

§2710 (e)(9)).

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1.0 EXECUTIVE SUMMARY

Bristol Environmental Remediation Services, LLC (Bristol), in compliance with the

Performance Work Statement (PWS) identified in Contract W912PL-12-D-0005, Task Order

0006, with the United States Army Corps of Engineers (USACE), Los Angeles District, has developed this Remedial Investigation (RI) and Feasibility Study (FS) Report for Munitions

Response Site (MRS) 01 − Range Complex (Project 3), which is associated with the Formerly

Used Defense Site (FUDS) known as Former Camp Elliott, East Elliott (East Elliot or MRS

01) (FUDS Project J09CA006703). The MRS is located in San Diego, California, approximately 12 miles northeast of downtown San Diego. The MRS was originally identified as encompassing 3,200 acres. Spatial adjustments have been made to the boundary to more accurately align it with the parcels adjacent to the site. As a result, the acreage associated with MRS 01 that was included in the RI study area is 3,035.5 acres. Figures 1-1 and 1-2 depict the site location and the site layout (Note: all figures referenced throughout this document are contained in Appendix F, Site Figures). Further site descriptions, including physical descriptions and previous investigations, are presented in Section 2.0.

The RI portion of this RI/FS Report (Sections 2.0 through 8.0) characterizes the nature and extent of Munitions and Explosives of Concern (MEC), Munitions Debris (MD), and

Munitions Constituents (MC) that may be present at the East Elliott MRS 01 − Range

Complex (Project 3). Bristol used RI data collected by another contractor under a separate contract to support the preparation of this RI/FS Report. The RI portion also includes hazard assessments (HA) that provide information to evaluate the potential MEC hazards to human receptors and risk assessments to evaluate the potential MC risk/hazard to human and/or ecological receptors. The FS portion of this RI/FS Report (Sections 9.0 through 12.0) uses information from the RI portion to develop, evaluate, and comparatively analyze potential

Remedial Action Alternatives (RAA) for each MRS.

The objectives of this RI/FS were accomplished using results of previous investigations, Digital Geophysical Mapping (DGM), and environmental sampling and analysis to collect data to characterize nature and extent of potential MEC, MD, potential impact areas, and MC.

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1.1 REMEDIAL INVESTIGATION

The RI field operations were conducted by Accord Engineering, Inc. (Accord) at the East

Elliott MRS from December 2012 through March 2014. The tasks conducted during the MEC and MC characterization for this RI included DGM using towed-array and man-portable equipment and environmental sampling and analysis (including background soil sampling).

No intrusive investigation of subsurface geophysical anomalies was completed during the RI.

The DGM data collected during the RI field operations identified areas that were potential impact areas (i.e., extent of MEC contamination), while the results of previous investigations at MRS 01 provided data to identify the potential munitions present (i.e., nature of MEC contamination); thus, the criteria for characterizing the nature and extent of MEC has been satisfied. A summary of RI field operations and the results are presented in Section 5.0.

MEC Characterization

No MEC was recovered during RI operations. Five MD items were identified on the surface during RI field operations and all were determined to be projectile fragments. Historical data, site conditions indicating U.S. Department of Defense (DoD) use, and the presence and distribution of unexploded ordnance (UXO) and MD items identified during previous investigations confirm the use of MRS 01 as an artillery and tank training area. A summary of the UXO and MD identified is included in Section 5.0.

Several previous investigations have been completed at East Elliott beginning in 1984. As part of the Engineering Evaluation/Cost Analysis (EE/CA) completed in 1996, the MRS was evaluated based on four sectors that were based on previous investigations to identify and recommend alternative actions conclusions documented in the EE/CA. The subdivision of the

3,035.5 acre MRS 01 was further refined during the development of this RI/FS report to facilitate the evaluation of the potential hazards to human health posed by the potential presence of MEC within these areas. These sub-areas are based on several factors including:

• Results of previous investigations,

• Distribution of UXO and MD,

• Results of RI field operations,

• Current and anticipated future land use, February 2018 1-3 Contract No. W912PL-12-D-0005

• Analysis of potential MEC hazard, and

• Potential for receptors to encounter MEC.

Based on these factors, the MRS has been divided into seven sub-areas (MRS 01a through

MRS 01g) (Figure 1-3). Table 2-1 provides a summary of the various names that have been associated with the sub-areas during previous investigations. Additional information presented throughout this report will support and clarify the division of the MRS into sub-areas. Following is a summary of the MEC and MD associated with each sub-area:

• MRS 01a – Sub-area MRS 01a comprises 121.1 acres. The historical information for East Elliott indicates the area was used as an impact area for artillery and tank training; however, there is no indication that any specific munitions-related activities occurred within sub-area MRS 01a. Surface MEC and MD were removed from accessible areas within this sub-area during a Time Critical Removal Action (TCRA) completed in 1998-1999. The Final Report for the TCRA indicates that clearance activities were completed within all the 100 foot (ft.) by 100 ft. grids located within MRS 01a.

Approximately 77 acres of total-coverage DGM were completed within MRS 01a during the RI field operations. There were no MEC or MD items found at MRS 01a during RI field operations. No intrusive investigations were completed related to the geophysical anomalies identified during the RI field operations. The geophysical results of the DGM surveys conducted during the RI field operations and previous investigations were analyzed using Visual Sample Plan (VSP) software, UXO Estimator, and ArcGIS software to identify areas within MRS 01a that had more than an estimated 400 geophysical anomalies per acre, which would be indicative of an activity that created a clustering of anomalies (e.g., an impact area). Anomaly densities throughout most of this sub-area as calculated by VSP are less than 50 anomalies per acre, with a maximum density of 315 anomalies per acre. Insufficient data was available related to MRS 01a to process information about the sub-area using UXO Estimator. According to the ArcGIS analysis, the mean UXO density within MRS 01a is 0.12 UXO/acres. The geophysical data results indicate that there appears to be no potential impact areas present because the density of anomalies is less than the threshold density of 400 that would suggest a potential impact area.

All available data indicates surface MEC is unlikely but potentially present within MRS 01a and the exposure pathways for surface MEC could be complete. Subsurface MEC is also unlikely but potentially present; therefore, the exposure pathways for subsurface MEC could be complete. Although no MEC was recovered in MRS 01a during the RI, one MEC item was found on the surface during the TCRA. There is the slight possibility for MEC to be present; therefore, the USEPA MEC Hazard Analysis (MEC HA) tool was used to evaluate the sub-area. Results of the MEC HA (under the future land use scenario) indicate a Hazard Level Category of 2 (i.e., high potential

February 2018 1-4 Contract No. W912PL-12-D-0005 explosive hazard condition) with a total score of 760; however, the MEC HA tool may potentially overestimate the hazard in this situation, where the probability of finding a UXO is low or unlikely, but cannot be ruled out.

Using the boundary identified by USACE St. Louis District (MVS) in 2013, the northeastern corner of the RI study area (approximately 0.5 acres) is no longer included in the MRS, as there is no historical information that indicates this area was within the boundary of the historical firing ranges and no MEC or MD have been found in this area. Therefore, the revised acreage for sub-area MRS 01a is 120.6 acres and the northeastern corner will become part of a new area labeled MRS 01g (see bullet below).

Based on historical information, previous investigations, and the results of the RI, MRS 01a (120.6 acres) was recommended for further evaluation in the FS (see Section 1.2).

• MRS 01b – Sub-area MRS 01b comprises 523.3 acres. The historical information for MRS 01b indicates the area was used as an impact area for artillery and tank training.

RI field operations conducted at MRS 01b consisted of MC soil sampling. No geophysical survey activities were conducted because extensive UXO clearance activities have previously been conducted within this sub-area. One MD item was observed within MRS 01b during the soil sampling activities. The item was approximately ¼-inch long by ¼-inch wide and appeared to be a projectile fragment.

Previous removal actions have covered approximately 271.9 acres of the sub-area.

MEC is not anticipated to remain within this area; therefore, surface and subsurface exposure pathways for MEC are considered incomplete in these areas. These removal actions have not been completed within approximately 218.2 acres that encompass the active landfill operations and are potential impact areas; however, this area has been extensively modified through cut-and-fill activities associated with the creation of the landfill. As a result, the surface and subsurface exposure pathways to MEC are considered incomplete because the presence of a landfill liner, trash, and fill dirt will prevent receptors from accessing native soils that may contain MEC. Approximately

33.2 acres of MRS 0lb have not been addressed during previous removal actions or investigations or modified during landfill operations.

No DGM surveys were conducted within MRS 01b during the RI field operations;

however, data from previous investigations and areas adjacent to the sub-area were analyzed using VSP and UXO Estimator. The purpose of the VSP analysis was to identify areas within the 33.2 acres of MRS 01b not previously investigated that had more than an estimated 400 geophysical anomalies per acre. The mean average density of geophysical anomalies as calculated by VSP for the 33.2 acres of the MRS sub-area is 34 anomalies per acre with a maximum of 109 anomalies per acre. The result of the UXO Estimator analysis indicates with a 95% confidence level that there is less than 0.38 UXO/acre.

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Although the VSP and UXO Estimator results indicate that no impact areas are present within the 33.2 acres, it is anticipated that MEC may be present on the surface and subsurface within this acreage based on the previous removal actions and investigations that have been completed in proximity to this area. The surface and subsurface exposure pathways for MEC in this area remain potentially complete.

Based on previous investigations results, there was sufficient evidence for the potential for MEC to be present to evaluate the MRS sub-area with the USEPA MEC HA. Results of the MEC HA (under future land use scenario) indicate the Hazard Level Category of 1 (i.e., highest potential explosive hazard conditions) with a total score of 920.

Based on historical information, previous investigations, and the results of the RI, MRS 01b (33.2 acres) was recommended for further evaluation in the FS (see…