10.2.5_-_2012_-_Feasability_Study_Oct_2012.pdf

FINAL

FEASIBILITY STUDY

DUPONT CHAMBERS WORKS FUSRAP SITE

DEEPWATER, NEW JERSEY

Contract No. W912WJ-06-D-0002 Delivery No. CF01

Prepared by:

U.S. ARMY CORPS OF ENGINEERS

PHILADELPHIA DISTRICT

PHILADELPHIA, PENNSYLVANIA

October 2012

Feasibility Study FINAL DuPont Chambers Works FUSRAP Site

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TABLE OF CONTENTS

1.0 INTRODUCTION AND NEED FOR ACTION ............................................. 1-1

1.1 Authority of Action .............................................................................................. 1-1

1.2 Background MED-Related Operational History .................................................. 1-3

1.3 Prior Investigations and Cleanups ....................................................................... 1-4

1.3.1 Atomic Energy Commission/Department of Energy ........................................................ 1-4

1.3.2 Oak Ridge National Laboratory 1977 ............................................................................. 1-4

1.3.3 Bechtel National, Inc. 1983 ............................................................................................. 1-5

1.3.4 DuPont 1988 - Present .................................................................................................... 1-5

1.4 Reasons for Remedial Actions ............................................................................. 1-6

1.5 Purpose and Scope of the FS ............................................................................. 1-10

1.6 Organization of the Report ................................................................................. 1-10

1.7 Community Involvement ................................................................................... 1-11

1.8 Consultation and Coordination with Other Agencies ........................................ 1-11

2.0 THE SITE AND AFFECTED ENVIRONMENT ........................................... 2-1

2.1 Site Description and History ................................................................................ 2-1

2.1.1 OU 1 - AOC 1, Former Building 845 Area ...................................................................... 2-1

2.1.2 OU 1, AOC 2, F Corral ................................................................................................... 2-2

2.1.3 OU 3, AOC 6, East Area .................................................................................................. 2-2

2.1.4 Environmental Setting ...................................................................................................... 2-3

2.2 Nature and Extent of FUSRAP Contamination ................................................... 2-7

2.2.1 Identification of Constituents of Potential Concern (COPCs) ......................................... 2-7

2.2.2 Soils ................................................................................................................................. 2-9

2.2.3 Groundwater .................................................................................................................. 2-11

2.2.4 Surface Water and Sediment .......................................................................................... 2-14

2.3 Contaminant Fate and Transport ........................................................................ 2-14

2.4 Summary of Baseline Risk Assessment Results ................................................ 2-16

2.4.1 Human Health Risk Assessment Summary ..................................................................... 2-17

2.4.2 Screening-Level Ecological Risk Assessment Summary ................................................ 2-21

3.0 IDENTIFICATION AND SCREENING OF REMEDIAL ACTION

TECHNOLOGIES ............................................................................................. 3-1

3.1 Introduction .......................................................................................................... 3-1

3.2 Development of Media-Specific Remedial Action Objectives (RAOs) .............. 3-2

3.3 Applicable or Relevant and Appropriate Requirements (ARARs) ...................... 3-5

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3.3.1 Definition of ARARs ......................................................................................................... 3-5

3.3.2 Types of ARARs ................................................................................................................ 3-7

3.3.3 Application of ARARs to Remedial Alternatives .............................................................. 3-8

3.4 Development of Remediation Goals (RGs) ....................................................... 3-11

3.5 Identification of General Response Actions (GRAs) ......................................... 3-13

3.5.1 Land Use Control ........................................................................................................... 3-13

3.5.2 Monitoring ..................................................................................................................... 3-13

3.5.3 Containment ................................................................................................................... 3-14

3.5.4 Removal ......................................................................................................................... 3-14

3.5.5 Treatment Actions .......................................................................................................... 3-14

3.5.6 Disposal Actions ............................................................................................................ 3-16

3.6 Volume/Area of Contaminated Media ............................................................... 3-18

3.7 Identification and Screening of Technology Types and Process Options ......... 3-18

3.7.1 No Action (Soil and Groundwater) ................................................................................ 3-19

3.7.2 Administrative and Legal Control Mechanisms (Soil and Groundwater) ..................... 3-19

3.7.3 Physical Mechanisms (Soil and Groundwater) ............................................................. 3-21

3.7.4 Environmental Monitoring ............................................................................................ 3-21

3.7.5 Containment (Soil and Groundwater) ........................................................................... 3-21

3.7.6 Soil Excavation .............................................................................................................. 3-23

3.7.7 Removal (Groundwater) ................................................................................................ 3-24

3.7.8 Physical Treatment (Soil) .............................................................................................. 3-24

3.7.9 Chemical Treatment (Soil) ............................................................................................. 3-26

3.7.10 Biological Treatment (Soil)............................................................................................ 3-27

3.7.11 Thermal Treatment (Soil) ............................................................................................... 3-27

3.7.12 Physical Treatment (Groundwater) ............................................................................... 3-27

3.7.13 Chemical Treatment (Groundwater) .............................................................................. 3-30

3.7.14 Biological Treatment (Groundwater) ............................................................................ 3-30

3.7.15 Thermal Treatment (Groundwater) ............................................................................... 3-31

3.7.16 Disposal Options (Soil and Groundwater) .................................................................... 3-31

3.8 Evaluation of Technologies and Process Options .............................................. 3-41

3.8.1 Administrative and Legal Mechanisms (Soil and Groundwater) ................................... 3-42

3.8.2 Environmental Monitoring ............................................................................................ 3-44

3.8.3 Capping (Soil) ................................................................................................................ 3-45

3.8.4 Soil Excavation (Soil) .................................................................................................... 3-46

3.8.5 Stabilization/Solidification (Soil) ................................................................................... 3-47

3.8.6 Ex Situ Vitrification (Soil) .............................................................................................. 3-48

3.8.7 Soil Washing .................................................................................................................. 3-49

3.8.8 Soil Sorting .................................................................................................................... 3-49

3.8.9 Onsite Disposal (Soil) .................................................................................................... 3-50

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3.8.10 Off-Site Disposal (Soil) .................................................................................................. 3-51

3.8.11 Vertical Barriers (Groundwater) ................................................................................... 3-52

3.8.12 Vertical and/or Horizontal Extraction Wells (Groundwater) ........................................ 3-52

3.8.13 Precipitation/Flocculation/Sedimentation (Groundwater) ............................................ 3-53

3.8.14 Reverse Osmosis (Groundwater) ................................................................................... 3-53

3.8.15 Ion Exchange (Groundwater) ........................................................................................ 3-54

3.8.16 Electrokinetics (Groundwater) ...................................................................................... 3-54

3.8.17 Monitored Natural Attenuation (Groundwater) ............................................................ 3-55

3.8.18 Geochemical Immobilization (Groundwater) ................................................................ 3-55

3.8.19 Onsite Discharge (Groundwater) .................................................................................. 3-56

3.8.20 Off-Site Disposal (Groundwater) ................................................................................... 3-56

3.8.21 Transportation Technologies (Soils and Groundwater) ................................................ 3-57

3.9 Selection of Representative Technologies ......................................................... 3-63

4.0 DEVELOPMENT AND SCREENING OF REMEDIAL ALTERNATIVES ...

.............................................................................................................................. 4-1

4.1 Introduction .......................................................................................................... 4-1

4.2 Contaminated Media and AOCs .......................................................................... 4-1

4.2.1 Soils and Debris ............................................................................................................... 4-2

4.2.2 Groundwater .................................................................................................................... 4-3

4.3 Description of Remedial Alternatives for Each Medium .................................... 4-3

4.3.1 Soils ................................................................................................................................. 4-4

4.3.2 Groundwater .................................................................................................................. 4-16

5.0 ANALYSIS OF REMEDIAL ALTERNATIVES ........................................... 5-1

5.1 Introduction .......................................................................................................... 5-1

5.1.1 Threshold Criteria ........................................................................................................... 5-2

5.1.2 Balancing Criteria ........................................................................................................... 5-2

5.1.3 Modifying Criteria ........................................................................................................... 5-4

5.2 Detailed Analysis of Remedial Alternatives ........................................................ 5-5

5.2.1 Alternatives S1-1, S1-6, GW1-1, GW1-6: No Action (Soils and Groundwater) ........... 5-11

5.2.2 Alternatives S2-1, S2-6: Excavation and Off-Site Disposal .......................................... 5-13

5.2.3 Alternatives S3-1, S3-6: Excavation of Soils, Treatment, and Off-site Disposal .......... 5-15

5.2.4 Alternatives GW2-1, GW2-6: Ex Situ Treatment of Groundwater ................................ 5-19

5.2.5 Alternatives GW3-1, GW3-6: Monitored Natural Attenuation ...................................... 5-23

5.3 Considerations Common to All Alternatives ..................................................... 5-25

5.3.1 Monitoring and Mitigative Measures ............................................................................ 5-25

5.3.2 Impact of Potential Loss of LUCs .................................................................................. 5-26

5.3.3 Short-term Uses and Long-term Productivity ................................................................ 5-27

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5.3.4 Final Status Surveys ....................................................................................................... 5-28

5.4 Comparative Analysis of Remedial Alternatives ............................................... 5-28

5.4.1 Comparison Using NCP Criteria ................................................................................... 5-31

5.5 Potential Combinations of Media-Specific Alternatives ................................... 5-34

6.0 REFERENCES ................................................................................................... 6-1

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LIST OF TABLES

Table 1-1: COPCS for Soil at Chambers Works FUSRAP Site ................................................. 1-7

Table 2-1: Results of Radiological Dose and Risk Assessment ............................................... 2-20

Table 3-1: Remedial Action Objectives for Remediation of Chambers Works FUSRAP Site .. 3-5

Table 3-2: Applicable or Relevant and Appropriate Requirements (ARARs) for Chambers Works FUSRAP Site................................................................................................ 3-10

Table 3-3: General Response Actions and Potential Process Options for DuPont Chambers Works FUSRAP Site................................................................................................ 3-17

Table 3-4: Estimate of In Situ Soil Volumes Above RG .......................................................... 3-18

Table 3-5: Identification and Screening of Technologies (Soils) ............................................. 3-33

Table 3-6: Identification and Screening of Technologies (Groundwater) ................................ 3-36

Table 3-7: Evaluation of Remedial Technologies and Process Options - Soil ......................... 3-58

Table 3-8: Evaluation of Remedial Technologies and Process Options - Groundwater .......... 3-60

Table 4-1: Estimated Volume of Contaminated Soil .................................................................. 4-3

Table 4-2: Estimate of Area and Thickness of Plumes ............................................................... 4-3

Table 4-3: Soil Alternatives ........................................................................................................ 4-4

Table 4-4: Process Options Contained in Each Alternative for Soil .......................................... 4-4

Table 4-5: Groundwater Alternatives ....................................................................................... 4-16

Table 4-6: Process Options Contained in Each Alternative for Groundwater .......................... 4-17

Table 5-1: Summary of Detailed Analysis of Alternatives - Soil ............................................... 5-6

Table 5-2: Summary of Detailed Analysis of Alternatives - Groundwater ................................ 5-9

Table 5-3: Comparative Analysis of Alternatives – Soil .......................................................... 5-30

Table 5-4: Comparative Analysis of Alternatives – Groundwater ........................................... 5-30

Table 5-5: Total Cost Estimate for Each Alternative ................................................................ 5-34

Table 5-6: Combinations of Media Specific Alternatives ........................................................ 5-35

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LIST OF FIGURES

Figure 1-1: Location of DuPont Chambers Works FUSRAP Site

Figure 1-2: Designations of FUSRAP Operable Units (OUs) and Areas of Concern (AOCs)

Figure 1-3: Location of AOCs Evaluated in this FS

Figure 2-1: Location of AOCs 1 and 2, the Central Drainage Ditch, and Historical Lagoon A (Basin Complex)

Figure 2-2: Land Use Areas

Figure 2-3: Total Uranium Concentrations in Soil and Concrete Samples for AOC 1

Figure 2-4: OU 1 Cross Section (A-A’)

Figure 2-5: AOC 1 View of Cross Section A-A’

Figure 2-6: Total Uranium Concentrations in Soil Samples for AOC 2 (OU 1)

Figure 2-7: AOC 2 View of Cross Section A-A’

Figure 2-8: Total Uranium Concentrations in Soil Samples for AOC 6 (OU 3)

Figure 2-9: AOC 6 Cross Section (B-B’)

Figure 2-10: Detailed View of Cross Section B-B’ in Area of East Road

Figure 2-11: Uranium Concentrations in Groundwater in OU 1, A Aquifer (AOCs 1 and 2)

Figure 2-12: Uranium Concentrations in Groundwater in OU 1, B Aquifer (AOCs 1 and 2)

Figure 2-13: Area of Interest 1 (AOI 1) Well Locations (AOC 4)

Figure 2-14: Uranium Concentrations in Groundwater in AOC 6, B Aquifer

Figure 2-15: Total Uranium Concentrations for Sediment and Surface Water Samples in

AOC 6 (OU 3)

Figure 2-16: General Conceptual Site Model

Figure 2-17: Site Layout including Exposure Units (EUs)

Figure 3-1: Total Uranium Isoconcentrations in Soil for AOC 1 (above Remediation Goal)

Figure 3-2: Total Uranium Isoconcentrations in Soil for AOC 2 (above Remediation Goal)

Figure 3-3: Total Uranium Isoconcentrations in Soil for AOC 6 (above Remediation Goal)

Figure 4-1: Assumed Excavation Cutlines and Volumes for OU 1

Figure 4-2: Assumed Excavation Cutlines and Volumes for AOC 6

Figure 4-3: Soil Excavation Location and Treatment Diagram for OU 1

Figure 4-4: Schematic of Soil Sorting System with Segmented Gate

Figure 4-5: Uranium in Groundwater – Mass Balance AOC 1

Figure 4-6: Uranium in Groundwater – Mass Balance AOC 2

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Figure 4-7: Uranium in Groundwater – Mass Balance AOC 6

Figure 4-8: Conceptual Layout and Process Flow Diagram of Groundwater

Treatment in OU 1

Figure 4-9: Conceptual Layout and Process Flow Diagram of Groundwater Treatment in

AOC 6

Figure 5-1: Detailed Analysis Criteria for the Evaluation of Remedial Alternatives

LIST OF APPENDICES

APPENDIX A: Determination of Remediation Goals for COCs

APPENDIX B: Cost Estimate Analysis

APPENDIX C: Technical Evaluation – Uranium Mass Balance

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LIST OF ACRONYMS AND ABBREVIATIONS

AEC Atomic Energy Commission

AOC Area of Concern

AOI area of interest

ARAR Applicable or Relevant and Appropriate Requirement bgs below ground surface

BCG biota concentration guideline

BNI Bechtel National, Inc.

BRA Baseline Risk Assessment

BTEX benzene, toluene, ethylbenzene, xylene

°C Celsius

CDD Central Drainage Ditch

CEA Classification Exception Area

CERCLA Comprehensive Environmental Response, Compensation and Liability Act

CERCLIS Comprehensive Environmental Response, Compensation and Liability Information System

CFR Code of Federal Regulations cfs cubic feet per second

COC Constituent of Concern

COPC constituent of potential concern

COPEC constituent of potential ecological concern cpm counts per minute

CSM Conceptual Site Model

DCGL Derived Concentration Guideline Levels

DE Delaware

DOE U. S. Department of Energy

EPC Exposure Point Concentration

EU exposure unit

EWDAA Energy and Water Development Appropriations Act

ESA Endangered Species Act

°F Fahrenheit

FS feasibility study ft feet ft2 square feet

FUSRAP Formerly Utilized Sites Remedial Action Program gpm gallons per minute

GRA general response action

HASP health and safety plan

HHRA Human Health Risk Assessment

HI Hazard Index

HPWDS Historic Process Water Ditch System

HSWA Hazardous and Solid Waste Amendments

IC institutional control

ILCR Incremental Lifetime Cancer Risk

ISV investigative screening value

IWS Inceptor Well System

LNAPL light non-aqueous phase liquid

LUC land use control

MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual

MCL maximum contaminant level

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MNA monitored natural attenuation mph miles per hour mrem/yr millirem per year msl mean sea level µg/L micrograms per liter µR/hr microroentgens per hour

MED Manhattan Engineer District

NCP National Oil and Hazardous Substances Pollution Contingency Plan

NESHAPs National Emission Standards for Hazardous Air Pollutants

NAVD 88 North American Vertical Datum of 1988

NJ New Jersey

NJAC New Jersey Administrative Code

NJDEP New Jersey Department of Environmental Protection

NPDES National Pollution Discharge Elimination System

NRC Nuclear Regulatory Commission

O&M operation and maintenance

OU Operable Unit

ORNL Oak Ridge National Laboratory

ORP Oxidation Reduction Potential

Pa-234m Protactinium-234m

PCB polychlorinated biphenyl

PIC Pressurized Ion Chamber

POTW publicly owned treatment works

PP Proposed Plan

PPE Personal Protective Equipment

PRG Preliminary Remediation Goal pCi/g picoCuries per gram pCi/L picoCuries per liter

Ra-226 Radium-226

RAGS Risk Assessment Guidance for Superfund

RAO remedial action objective

ROD Record of Decision

RCRA Resource Conservation and Recovery Act

RESRAD Residual Radioactivity

RFI RCRA Facility Investigation

RG remediation goal

RI Remedial Investigation

RME Reasonable Maximum Exposure

SGS Segmented Gate System

SLERA Screening-Level Ecological Risk Assessment

SVOC semi-volatile organic compound

SDWA Safe Drinking Water Act

SWMU solid waste management unit

TAL Target Analyte List

TBC To Be Considered

TCL Target Compound List

TERP Transportation and Emergency Response Plan

Th-230 Thorium-230

Th-234 Thorium-234

U uranium

U(4+) tetravalent uranium

U(6+) hexavalent uranium

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UF4 green salt

UF6 uranium hexafluoride

U-234 Uranium-234

U-235 Uranium-235

U-238 Uranium-238

U3O8 black oxide

UO2 brown oxide

USACE U.S. Army Corps of Engineers

USEPA U.S. Environmental Protection Agency

USFWS U.S. Fish and Wildlife Service

UCL upper confidence limit

WWTP wastewater treatment plant yd3 cubic yard

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1.0 INTRODUCTION AND NEED FOR ACTION

This Feasibility Study (FS) report was prepared by the U.S. Army Corps of Engineers (USACE), Philadelphia District with technical support from Cabrera Services, Inc. (CABRERA) under contract number W912WJ-06-D-0002/CF01 for the DuPont Chambers Works Site. The Site is currently being addressed under the Formerly Utilized Sites Remedial Action Program (FUSRAP) managed by the USACE.

1.1 Authority of Action

The DuPont Chambers Works (Chambers Works) in Deepwater, New Jersey (NJ) is an active chemical manufacturing facility owned and operated by E.I. DuPont de Nemours & Company

(DuPont). The U.S. Army Corps of Engineers Manhattan Engineer District (MED) and the

Atomic Energy Commission (AEC) contracted with DuPont to process uranium at Chambers

Works in the 1940s. The USACE – Philadelphia District is conducting a program to investigate and clean up, if necessary, eligible residual contamination resulting from these activities.

USACE is utilizing the administrative, procedural, and regulatory provisions of the

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended (CERCLA) [42 U.S.C §9601 et seq.], and the National Oil and Hazardous

Substances Pollution Contingency Plan (NCP) [40 C.F.R Part 300] to guide the investigations at three operable units (OUs) within the Chambers Works property.

In 1974, the AEC (succeeded by the U.S. Department of Energy, [DOE]) established a site investigation and cleanup program that later became FUSRAP. FUSRAP was initiated to identify, investigate, and clean up or otherwise control sites where residual radioactivity remained from activities conducted under contract to the MED or the AEC during the early years of the nation’s atomic energy program, or from commercial operations as directed by Congress.

On October 13, 1997, Congress transferred the administration and cleanup of eligible FUSRAP sites from the DOE to USACE as part of the 1998 Energy and Water Development

Appropriations Act (EWDAA). FUSRAP is a jointly managed program by both the DOE and

USACE. USACE is conducting FUSRAP site cleanups under Congressional appropriations subject to the direction contained in Public Law 106-60, §611: the EWDAA for Fiscal Year

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2000. This law directs USACE to conduct response actions for releases related to the nation’s early atomic energy program subject to the provisions of the CERCLA and the NCP.

The DuPont Chambers Works Site is a 1,455-acre complex which includes Chambers Works chemical manufacturing area (referred to as Chambers Works) and the former Carneys Point

Smokeless Powder Works (referred to as Carneys Point Works). Figure 1-1 shows the location of the Chambers Works within Pennsville and Carney Point Townships, along the southeastern shore of the Delaware River, just north of the I-295 Delaware Memorial Bridge, and adjacent to the residential community of Deepwater, NJ. MED activities were conducted only within the

700-acre Chambers Works site. No MED research, processing activities or waste disposal occurred within the Carneys Point Works, located in the northern portion of the property, and therefore, that area is not part of the FUSRAP investigation. For the purposes of this report the areas investigated under FUSRAP will be referred to collectively as the DuPont Chambers

Works FUSRAP Site (the Site) in order to distinguish the FUSRAP areas and activities from

DuPont’s overall manufacturing complex and operations.

Based on previous DOE investigations regarding the nature of past MED activities in each area, USACE initially identified six potentially-impacted areas, referred to as areas of concern

(AOCs). To facilitate further investigations and remedial decisions, the USACE organized the six AOCs into three OUs under FUSRAP. Additionally, USACE evaluated the wastes and materials used in MED operations and identified the constituents of potential concern (COPCs) that would be eligible for FUSRAP investigation and remediation (CABRERA 2011a).

USACE performed separate investigations at each of the following OUs between 2000 and 2007:

OU 1: Former Building 845 (AOC 1) and F Corral (AOC 2) - These AOCs were production areas where uranium refinement processes occurred.

OU 2: Central Drainage Ditch (CDD) (AOC 3) and the J-26 Area (former location of Building J-16) (AOC 5) - These AOCs include the location of a former laboratory building (J-16) and drainage ditches through which processing wastes were discharged.

OU 3: Historical Lagoon A (AOC 4) and the East Area (AOC 6) - These AOCs were disposal areas for building rubble, discarded equipment, and process wastes.

Figure 1-2 is an aerial view of the Chambers Works property outlining the FUSRAP OUs, the six corresponding AOCs. For subsequent risk evaluation, the AOCs were grouped into five separate

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exposure units (EU) based on physical location within the Site (see Figure 2-17). The EUs correspond with the FUSRAP OU designations, as follows:

EU 1 – OU 1 (AOC 1 and AOC 2)

EU 2A, EU 2B – OU 2 (AOCs 3 and 5, respectively)

EU 3A , EU 3B - OU 3, (AOCs 4 and 6, respectively)

Results of the FUSRAP investigations including site characteristics and nature and extent of contamination are detailed in the Final Sitewide Remedial Investigation Report for all Operable

Units, DuPont Chambers Works FUSRAP Site (CABRERA 2011b). The Final Baseline Risk

Assessment, DuPont Chambers Works FUSRAP Site, Deepwater, New Jersey, was completed based on RI sampling results, to evaluate actual and potential risks to human health and the environment (CABRERA 2011c). Results of the RI and baseline risk assessment (BRA) are summarized in Section 2 of this report.

1.2 Background MED-Related Operational History

MED operations involving uranium began at Chambers Works in 1942. MED contracted with

DuPont to perform several uranium-processing activities. In 1946, all MED activities were transferred to the AEC, and DuPont continued research for AEC until late 1947. DuPont’s contracts with MED involved the following uranium refinement processes, which were performed in OU 1:

Brown oxide process, Recovery process, Green salt process, and

Metal process.

Descriptions of these processes are further discussed in Section 1.5 of the Sitewide RI report. In addition to these processes, Chambers Works also converted quantities of green salt (uranium tetrafluoride) to uranium hexafluoride. This process, known as the hexafluoride process, was performed at the former Building J-16 (OU 2). Pilot-scale work on the brown oxide, green salt, and recovery processes also took place in the former Building J-16 (currently the Building J-26

Area).

DOE has estimated that more than half of the feedstock sent to Chambers Works was uranium-bearing scrap that was processed to uranium peroxide dihydrate and then used in the Brown

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Oxide Process (DOE 1997). Other research involving radioactive materials was also performed onsite but there was no enriched or depleted uranium produced or used at Chambers Works.

All uranium refining processes at production scale took place in OU 1 (AOCs 1 and 2) while some small scale testing took place in AOC 5. Chambers Works converted scrap and dross (the scum that forms on the surface of molten metal) into uranium peroxide dihydrate in AOC 1, Buildings 101 and 102. These buildings adjoined each other and were later collectively called

Building 845. During processing, 5,486 tons of scrap material were converted to 982 tons of black oxide. In AOC 2 uranium peroxide and other oxides were processed in Buildings 708 and

205, ultimately producing (through several steps) uranium tetrafluoride and uranium metal.

1.3 Prior Investigations and Cleanups

1.3.1 Atomic Energy Commission/Department of Energy

In 1948 and 1949, AEC conducted radiological surveys and decontamination of building surfaces at the Site. In 1949, following a radiological survey based on then-existing criteria, AEC released the buildings back to DuPont. DuPont demolished Building J-16 after it was released by AEC and in the process excavated several feet of soil from beneath the building

(DOE 1996). Building J-26 was subsequently constructed over the Building J-16 footprint.

1.3.2 Oak Ridge National Laboratory 1977

Oak Ridge National Laboratory (ORNL) conducted a radiation survey of the Chambers Works site in 1977 (ORNL 1978). The results of the survey in the F Parking Corral Area (AOC 2) indicated exposure rates were consistent with background radiation levels. Two soil borings were obtained in the F Parking Corral Area, along with one water sample. Uranium-238 (U-238) results were reported, and ranged up to 6.8 picoCuries per gram (pCi/g) in the soil samples and

1.8 picoCuries per liter (pCi/L) in the water samples.

External gamma radiation levels along the CDD (AOC 3) indicated exposure rates of 3 to 23 microroentgens per hour (μR/hr), which exceeded background radiation levels. Five soil borings were taken along the drainage ditch. A water sample was collected from one of the boreholes which yielded 0.67 pCi/L for U-238.

In the East Area (AOC 6), external gamma radiation levels indicated an exposure rate of 12.2 to

15 µR/hr, which exceeded the background radiation level of 4.5 µR/hr. Ten soil borings were

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performed along the East Area drainage ditch. Groundwater samples collected from two soil borings yielded total uranium concentrations between 9 micrograms per liter (µg/L) and 36 µg/L.

1.3.3 Bechtel National, Inc. 1983

Bechtel National, Inc. (BNI) performed a radiation survey of the Chambers Works in 1983 (BNI

1985). Survey results available for several of the AOCs described in the RI are summarized below.

In the F Parking Corral (AOC 2), near-surface gamma radiation measurements were collected.

The average background reading for this area as established by ORNL was 2,500 counts per minute (cpm). All measurement readings were below this average background level, with the exception of one, which had a maximum reading of 5,020 cpm. External gamma radiation, as measured by a pressurized ion chamber (PIC) yielded dose rates ranging from 11.6 to 13.8 µR/hr as compared to average background of 4.5 µR/hr. Nineteen boreholes were drilled in the F

Parking Corral Area. Based on gamma logs, subsurface contamination was indicated in layers to a depth greater than 9 feet (ft). Results from the analysis of two soil samples, collected using a

Shelby tube, indicated that U-238 was the major contaminant with concentrations ranging from

0.90 to 4,380 pCi/g. Eleven groundwater samples were also collected from the boreholes and analyzed, with results showing total uranium concentrations ranging from 1.8 to 105,105 pCi/L.

Near-surface gamma radiation measurements performed in the CDD (AOC 3) indicated surface activities that were elevated above background (i.e., a maximum of 14,532 cpm compared to a background of 2,500 cpm). External gamma radiation yielded dose rates ranging from 13 to 15 µR/hr, compared to a background reading of 4.5 µR/hr. Fifteen sediment samples were collected along the CDD. These samples were taken between 0-6 inches below the sediment surface (bgs).

No samples deeper than 6 inches and no water samples were collected in this area.

1.3.4 DuPont 1988 - Present

DuPont has been conducting Resource Conservation and Recovery Act (RCRA) corrective actions at Chambers Works since 1988, completely unrelated to the ongoing FUSRAP investigations. The USEPA Comprehensive Environmental Response, Compensation and

Liability Information System (CERCLIS) identification number for Chambers Works is

NJD002385730. The Hazardous and Solid Waste Amendments (HSWA) permit (No.

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NJO02395730) was issued by U.S. Environmental Protection Agency (USEPA) to Chambers

Works on November 7, 1988. As part of its RCRA investigation, DuPont has designated the areas of former MED activity as Solid Waste Management Unit (SWMU) 33. USACE is responsible for the investigation and cleanup of the areas used to support the nation’s early atomic energy program. In accordance with its RCRA permit requirements, DuPont operates an extensive sitewide pump and treat system in order to control off-site migration of chemical contaminants in groundwater. These chemical contaminants resulted from manufacturing operations by DuPont and are unrelated to the FUSRAP constituents in groundwater. The pump and treat system, referred to as the Inceptor Well System (IWS), provides hydraulic containment of contaminants in groundwater, including FUSRAP-related contamination. DuPont began operation of the IWS in 1970.

DuPont submitted a RCRA Facility Investigation (RFI) Report to the New Jersey Department of

Environmental Protection (NJDEP) and USEPA in 1995. The aquifers beneath Chambers Works are classified as Class IIA groundwater by the State of New Jersey. This classification indicates a designated use or potential use as a potable water source using conventional treatment (NJAC

7:9C). NJDEP has designated Chambers Works as a Classification Exception Area (CEA) where the designated uses (i.e., potable water source) are suspended for the duration of the CEA. This classification is tied to the duration of DuPont’s New Jersey Pollution Discharge Elimination

System (NJPDES) discharge to groundwater (DGW) permit and is re-evaluated every five years at the time of permit renewal.

1.4 Reasons for Remedial Actions

USACE is preparing this FS in accordance with CERCLA and the NCP for cleanup of contaminants resulting from work performed as part of the Nation's early atomic energy program. This document evaluates the alternatives for remedial action at the Site. It is based on historical data and the results of the Sitewide RI, which contains information on the nature and extent of contamination, and the BRA, which evaluates potential health and ecological risks which would exist if no remedial action were to be taken and no land use controls were to be implemented.

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The Sitewide RI report (CABRERA 2011b) summarizes the data and analytical results from radiological and chemical characterization surveys and field investigations conducted at the Site from 2000 through 2007. These studies were undertaken to determine the nature and extent of contamination and to characterize the geologic and hydrogeologic features of the property. The results from the RI indicate that elevated uranium concentrations above the Investigative

Screening Value (ISV) of 14 pCi/g (total uranium) were found in each AOC from each OU (with the exception of AOC 5); however, OU 1 (AOC 1 and AOC 2) and OU 3 (AOC 6) were the only areas with unacceptable risk, as determined in the BRA (CABRERA 2011c).

Based on the knowledge of feedstocks received at Chambers Works, MED manufacturing processes, and final products, the USACE identified the COPCs that are MED-related wastes/materials and therefore eligible for FUSRAP cleanup (CABRERA 2011a). The COPCs identified are the six initial radionuclides in the U-238 decay chain (including Radium-226 (Ra-

226)), plus Uranium-235 (U-235). However, due to the short half-lives of Thorium-234 (Th-

234) and Protactinium-234m (Pa-234m) (assumed to be in secular equilibrium with respect to U-

238), these two radionuclides are not considered as distinct COPCs. Similarly, due to its short half-life, Thorium-231 (Th-231) is assumed to be in secular equilibrium with respect to its parent, U-235, and is not considered as a separate COPC for the Site. Therefore, five radionuclides have been identified as eligible contaminants, COPCs, for the FUSRAP investigation and cleanup: U-234, U-235, U-238, Th-230, and Ra-226.

Table 1-1: COPCS for Soil at Chambers Works FUSRAP Site

U-238 Decay Chain Symbol Element Radiation Half-Life Decay Product

U-238 Uranium-238 Alpha 4,460,000,000 years Th-234 Th-2341 Thorium-234 Beta 24.1 days Pa-234m

Pa-234m1 Protactinium-234m Beta 1.17 minutes U-234 U-234 Uranium-234 Alpha 247,000 years Th-230 Th-230 Thorium-230 Alpha 80,000 years Ra-226 Ra-226 Radium-226 Alpha 1,602 years Rn-222

U-235 Decay Chain U-235 Uranium-235 Alpha 700,000,000 years

Th-231 Th-2312 Thorium-231 Beta 25.52 hours

1 Due to very short half-lives (<180 days), daughter products Th-234 and Pa-234m are in secular equilibrium with respect to their parent, U-238. Therefore, those daughter products will not be considered as separate COCs in the FS.

2 Due to very short half-lives (<180 days), daughter product Th-231 is in secular equilibrium with respect to its parent, U-235. Therefore, it will not be considered as a separate COC in the FS.

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The BRA report (CABRERA 2011c) evaluated the potential risks and doses for both current and hypothetical future reasonable maximum exposure (RME) receptors of the Site. Potential carcinogenic and noncarcinogenic risks to human health and the environment were quantified and compared to acceptable risk ranges under CERCLA. In addition, radiological doses for both current and hypothetical future RME receptors were calculated and compared to acceptable dose limit.

As discussed further in Section 2, the BRA results indicate that the maximum risk to industrial workers at EU 3B exceeded the CERCLA acceptable target risk range, and for EU 1, the maximum risk was at the upper end of the acceptable risk range. Furthermore, the maximum dose for construction workers and utility workers at EU 1, and the maximum dose for industrial workers and construction workers at EU 3B exceeded the acceptable dose limit.

Because the maximum risk and dose calculated for AOC 3, AOC 4, and AOC 5 did not exceed their corresponding acceptable risk and dose criteria for either current or future RME receptors, it was determined that no remedial action is required for these areas and they will not be further evaluated in this FS. Based on BRA results, remedial actions will be evaluated for OU 1 (AOCs

1 and 2) and AOC 6. The results of radiological risk and dose assessments also showed that the five radionuclides contribute to the majority of the risks and doses to various receptors present

(CABRERA 2011c). Therefore, the radionuclides U-234, U-235, U-238, Thorium-230 (Th-230), and Ra-226 have been identified as the constituents of concern (COCs) for the Site and considered for evaluation in the FS.

In addition to radiological COCs, the BRA also identified two metals (antimony and nickel), three semivolatile organic compounds (SVOCs) (benzo(a)pyrene, benzo(a)anthracene, and azobenzene) and one polychlorinated biphenyl (PCB) congener, Aroclor 1254, as major chemical risk contributors for the Site. However, USACE evaluated potential chemical compounds that were utilized during the MED uranium processing and none of the above mentioned chemical constituents were identified as FUSRAP eligible contaminants (CABRERA

2011a). Since no chemical constituents were considered as COCs for the DuPont Chambers

Works FUSRAP Site, only the five radionuclides (U-234, U-235, U-238, Th-230 and Ra-226) will be evaluated for possible remedial actions. In instances where non-FUSRAP chemical

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constituents are commingled (located) with the FUSRAP-eligible COCs, by necessity, those chemical constituents will be addressed and cleaned up. Therefore, the presence of non-

FUSRAP chemical constituents will be considered in the FS from a cost perspective, as they could potentially affect health and safety measures, treatment and disposal options, and overall project costs.

The BRA did not identify any major risk contributors in surface water or sediment (CABRERA

2011c). Therefore, no COCs were identified for these two pathways.

Except for inhalation of volatiles from groundwater for the construction and utility worker scenarios, groundwater was not evaluated for four RME scenarios. Since volatile organic constituents are not FUSRAP-related constituents, and none of the FUSRAP-related radioactive

COPCs are volatile, the groundwater exposure pathway is incomplete for FUSRAP-eligible constituents. In addition, current groundwater conditions preclude its use as a potential drinking water source. This is because the two uppermost aquifers exhibit high organic, metal, and salt contamination due to DuPont manufacturing operations. Accordingly, at the present time, the designated use of the Class II groundwater beneath Chambers Works as a potable water source is suspended for the duration of the CEA. This exception is re-evaluated every five years as part of

DuPont’s groundwater remediation plan and NJPDES DGW permit renewal for the property.

Sitewide RI results show that radioactive contamination in groundwater is encountered in areas where elevated uranium concentrations exist in soil (i.e., co-located contamination). Since there is the potential for radiological constituents present in the soil to leach into and impact groundwater at the Site, groundwater remedial alternatives will be evaluated for those areas requiring a remedial action for soils. Therefore, groundwater is evaluated for OU 1 and AOC 6 in this FS. It is expected that completed soil remedial action(s) will eliminate or minimize the radioactive contamination found in groundwater by addressing its source (i.e., soils) at the Site.

The RI, BRA, and FS comprise the primary evaluation documents. The Proposed Plan (PP) is published as a separate document and is the primary document to communicate the remedial alternatives evaluated and USACE’s preferred remedial alternative to the community for consideration. The RI/FS/PP process includes review and coordination with the NJDEP, W912WJ-06-D-0002/CF01 CABRERA SERVICES INC. 1-10

USEPA, and appropriate local agencies as well as public participation activities with affected stakeholders. The process concludes with the issuance of a Record of Decision (ROD) that selects the remedial alternative(s) for the DuPont Chambers Works FUSRAP Site.

1.5 Purpose and Scope of the FS

This FS identifies, develops, and evaluates remedial action alternatives to achieve a final remedy of eligible contaminants in soil and groundwater. The uranium isotopes (U-238, U-235, and U-

234), Ra-226, and Th-230 are identified as the COCs contributing to unacceptable human health risks and doses under RME scenarios in three FUSRAP AOCs: AOCs 1, 2, and 6. AOCs 1 and 2 are in close proximity and are similar in physical characteristics and contaminant distribution, and will therefore be considered together. Candidate remedial alternatives, their evaluation, and selection will be the same for AOCs 1 and 2. AOC 6 has different physical characteristics and will be evaluated separately, possibly resulting in selection of a remedial alternative that is different from that selected for AOCs 1 and 2.

Groundwater is not addressed as a source medium within this FS but is addressed only as a potential transport mechanism for soil COCs. As mentioned previously, groundwater remedial alternatives will be evaluated for those areas (OU 1 and AOC 6) that require a remedial action for soil. Alternatives are developed on the basis of the nature and extent of contamination documented in the RI, the BRA, and related reports. Figure 1-3 shows the location of AOCs addressed by this FS.

1.6 Organization of the Report

This FS is organized consistent with available guidance from the USEPA and USACE. The general overview of the site, the need for action, and the scope of this FS are presented in Section

1. Section 2 of this report describes the DuPont Chambers Works FUSRAP Site, its history, and environmental setting. This section also summarizes the nature and extent of contamination from radiological constituents, the transport of these materials, and results of the BRA. In

Section 3, remedial action objectives, applicable or relevant and appropriate requirements

(ARARs) and remediation goals (RGs) are defined and remedial action technologies are identified and screened for their effectiveness in meeting those goals. The development and screening of remedial action alternatives are presented in Section 4. In Section 5, a detailed analysis of potential remedial alternatives using CERCLA guidance evaluation criteria is

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presented. Section 5 also provides a comparative analysis of the remedial alternatives for the

DuPont Chambers Works FUSRAP Site. Section 6 lists the references used in this report.

Appendix A provides the determination of the RGs for COCs present at the Site. Appendix B provides a detailed summary of the cost estimates developed for each remedial alternative.

Appendix C includes uranium mass balance calculations that evaluate current uranium concentrations in groundwater and expected post remedial action residual concentrations.

1.7 Community Involvement

Scoping meetings help determine the range of issues to be addressed during the CERCLA process by identifying potential actions and significant issues to be addressed, the range of alternatives to be evaluated, the relevance of existing information, and areas where more information is needed. The USACE has conducted regular scoping and strategic planning sessions with internal team members throughout the various investigations at the Site.

Community involvement has been an integral component of the remedial program and has been implemented by working closely with and meeting with various community groups. USACE has partnered with community members and held community meetings since 2000 to maintain an open dialogue about site investigations and remedial plans.

Early in the CERCLA remedial action process, USACE held regular and frequent community meetings in order to share information with interested stakeholders about FUSRAP activities at the DuPont Chambers Works FUSRAP Site consistent with community involvement requirements in CERCLA and the NCP. Additionally, USACE has established a public website for the DuPont Chambers Works Site at http://fusrap.eaest.com/. Through its community involvement program, the USACE provides opportunities for an exchange of information with the public through news releases, community and public meetings, availability sessions, mailings, newsletters, project website, and public review and comment of documents. A copy of the DuPont administrative record is maintained by the USACE at the Salem Community College

Library, located at 406 Hollywood Avenue, Carneys Point, NJ.

1.8 Consultation and Coordination with Other Agencies

As previously mentioned, USACE is the lead agency for remedy selection and for conducting the

FUSRAP cleanup of the Chamber Works FUSRAP site pursuant to Public Laws 105-62 and 106-

60 §611. USACE coordinates with NJDEP and USEPA Region 2, the regulatory agencies with

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responsibilities to oversee activities at the Site. NJDEP and USEPA are responsible for overseeing the RCRA corrective action program implemented by DuPont throughout the facility.

These corrective actions…