PB98-964503
EPA 541-R98-029
October 1998
EPA Superfund
Record of Decision:
Travis Air Force Base
North, East, and West Industrial OU
Solano County, CA
12/3/1997
-------
Installation Restoration Program
Travis Air Force Base
Groundwater Interim
Record of Decision
December 1997
-------
GROUNDWATER INTERIM RECORD OF DECISION
NORTH, EAST, AND WEST INDUSTRIAL OPERABLE UNIT
TRAVIS AIR FORCE BASE
Final
60th Air Mobility Wing
Travis Air Force Base, California
Contract Number F41624-94-D-8049/D.O. 0035
3 December 1997
-------
TABLE OF CONTENTS
Page
TABLE OF CONTENTS i - iv
LIST OF FIGURES v
LIST OF TABLES : vi-vii
LIST OF ACRONYMS AND ABBREVIATIONS viii - xii
PART I DECLARATION 1-10
PART II DECISION SUMMARY 11-151
1.0 NEWIOU DESCRIPTION 11
1.1 Physical Description . 13
1.2 Land Use 16
1.3 Ecology 17
1.4 Geology and Hydrogeology 19
1.4.1 Geology 19
1.4.2 Hydrogeology 23
1.4.3 Groundwater Gradient and Flow 23
1.4.4 Aquifer Tests 26
1.4.5 Regional Groundwater Use 28
1.4.6 Surface Water 29
2.0 OVERVIEW OF TRAVIS AFB ENVIRONMENTAL PROGRAMS 31
2.1 Non-CERCLA Environmental Programs 31
2.1.1 Air Force Regulations and Management Action Plan 31
2.1.2 Resource Conservation Recovery Act and Hazardous Waste
Management Program 32
2.1.3 Petroleum-Only Contaminated Sites Program (POCOS) 33
2.1.4 Stormwater Discharge Permit 33
2.1.5 Pollution Prevention Program 33
2.2 CERCLA Environmental Programs 34
2.2.1 CERCLA Process 34
2.2.1.1 General CERCLA Process, Remedial Investigation/
Feasibility Study/Record of Decision/Proposed Plan/
Remedial Design/Remedial Action 34
Travis AFB Groundwater IROD i as of 3 December 1997
-------
TABLE OF CONTENTS (Continued)
Page
2.2.2 CERCLA Activities at Travis AFB 36
2.2.2.1 Removal Actions 39
2.2.2.2 Treatability and Pilot Studies 40
2.2.3 CERCLA Activities for Groundwater atNEWlOU 41
2.2.3.1 Human Health Risk Assessments 41
2.2.3.2 Ecological Risk Assessments 41
2.2.3.3 RI/FS Activities 42
2.2.3.4 Community Participation 42
2.2.3.5 Remedial Design/Remedial Action 44
3.0 SUMMARY OF NEWIOU GROUNDWATER REMEDIAL
INVESTIGATION 45
3.1 Nature and Extent of Contamination 45
3.1.1 North Operable Unit 46
3.1.2 East Industrial Operable Unit 49
3.1.3 West Industrial Operable Unit 53
3.2 Conceptual Model of Contamination 55
3.3 Risk Evaluation 60
3.4 Contaminants of Concern 72
3.5 Summary 73
4.0 SUMMARY OF NEWIOU GROUNDWATER FEASIBILITY STUDY 75
4.1 Alternative Description : 75
4.1.1 No Action 77
4.1.2 Natural Attenuation/Monitoring (Institutional Actions) 77
4.1.3 Extraction, Treatment, and Discharge 77
4.1.3.1 Extraction 78
4.1.3.2 Treatment 78
4.1.3.3 Discharge 79
4.2 Summary of Comparative Analysis of Alternatives 79
4.2.1 Threshold Criteria 80
4.2.1.1 Overall Protection of Human Health and the
Environment 80
4.2.1.2 Compliance with ARARs 80
Travis AFB Groundwater IROD 11 as of 3 December 1997
-------
TABLE OF CONTENTS (Continued)
Page
4.2.2 Primary Balancing Criteria 83
4.2.2.1 Long-Term Effectiveness and Permanence 83
4.2.2.2 Reduction of Toxicity, Mobility, and Volume
through Treatment 83
4.2.2.3 Short-Term Effectiveness 83
4.2.2.4 Implementability 84
4.2.2.5 Cost 84
4.2.3 Modifying Criteria 85
4.2.3.1 State Acceptance 85
4.2.3.2 Community Acceptance 87
4.2.4 Comparative Analysis 87
4.2.4.1 Total Score 89
4.2.4.2 Benefit/Cost Ratio 89
4.2.4.3 Conclusion 89
5.0 INTERIM REMEDIAL ACTIONS 91
5.1 Selected Interim Remedial Actions 91
5.1.1 Justification for Selected Interim Remedial Actions 97
5.1.2 Institutional Actions 99
5.1.3 Groundwater Monitoring 100
5.2 Alternative Description 100
5.2.1 Alternative 2 - Natural Attenuation/Monitoring 100
5.2.1.1 Definition of Natural Attenuation 102
5.2.2 Alternative 3 - Extraction, Treatment, and Discharge 104
5.2.2.1 Extraction Strategy and Technology 104
5.2.2.2 Treatment Strategy and Technologies 105
5.2.2.3 Discharge 108
5.3 Statutory Determinations 110
5.3.1 Protectiveness 111
5.3.2 Applicable or Relevant and Appropriate Requirements 111
5.3.3 Cost Effectiveness 112
5.3.4 Use of Permanent Solutions, Alternative Treatment, or
Resource Recovery Technologies 112
5.3.5 Preference for Treatment as a Principle Element 112
5.3.6 State and Community Acceptance 113
5.4 RD/RA Implementation and Schedule 113
5.5 Documentation of Significant Changes 115
Travis AFB Groundwater IROD lii as of 3 December 1997
-------
TABLE OF CONTENTS (Continued)
Page
6.0 APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS AND PERFORMANCE STANDARDS 116
6.1 Overview 116
6.2 ARARs Identification, Development, and Evaluation 118
6.3 Interim Record of Decision Concept 120
6.4 Determination of ARARs for the Interim Action 120
6.5 ARARs Evaluation and Discussion 121
7.0 REFERENCES 149
PART III RESPONSIVENESS SUMMARY.... 152-156
APPENDIX A: SITE-SPECIFIC SUMMARIES A-l - A-73
APPENDIX B: MONITORING STRATEGY B-l - B-10
Travis AFB Ground water IROD iv as of 3 December 1997
-------
LIST OF FIGURES
Page
1-1 Regional Location Map, Travis AFB 12
1-2 Travis AFB and Operable Units 14
1-3 Travis AFB/Maj or Annexes Location Map 15
1-4 Geological Map of Travis AFB and Vicinity 20
1-5 Hydrologic Boundaries and Geographic Proximity of Sites 25
1-6 Location of On-Site Surface Water and Storm Sewer Systems, Travis AFB 30
3-1 NEWIOU Groundwater Sites and Extent of Groundwater Contamination 47
3-2 NOU Sites and Areas with Groundwater Contamination 48
3-3 EIOU Sites with Groundwater Contamination 50
3-4 WIOU Sites with Groundwater Contamination 54
3-5 Maximum Contaminant Concentration from Monitoring Wells,
NEWIOU Groundwater Sites 57
3-6 Areas of Potential Groundwater Inflow into Stormwater Sewer System,
Travis AFB 59
4-1 The Nine CERCLA Criteria 81
5-1 Selected Alternatives for NEWIOU IRP Sites with Groundwater
Contamination 94
Travis AFB Groundwater IROD V as of 3 December 1997
-------
LIST OF TABLES
Page
1-1 Geologic Column — Travis AFB and Vicinity, California 21
1-2 Summary of Hydraulic Conductivity Values 27
2-1 Description of NEWIOUIRP Sites with Groundwater Contamination 37
3-1 Summary of IRP Sites, Groundwater Contaminants, and Risks 61
3-2 Summary of NEWIOU Groundwater Sites Carried Forward to the
NEWIOU FS 74
4-1 Comparison of Alternatives Versus the CERCLA Threshold and Balancing
Evaluation Criteria 82
4-2 Summary of Comparative Costs (thousands of dollars) 86
4-3 Remedial Alternative Evaluation Criteria Rating System 88
5-1 Interim Remedial Action Objectives for NEWIOU Groundwater IROD 92
5-2 Interim Remediation Goals for NEWIOU Groundwater IROD 93
5-3 Selected Interim Remedial Actions for NEWIOU IRP Sites with
Groundwater Contamination 95
6-1 Federal ARARs - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements 127
6-2 State ARARs - Groundwater Remediation (IROD)
Air Remediation Requirements 133
6-3 State ARARs - Groundwater Remediation (IROD)
Fish and Game Requirements 135
6-4 State ARARs - Groundwater Remediation (IROD)
Water Board Requirements 137
Travis AFB Groundwater IROD VI as of 3 December 1997
-------
LIST OF TABLES (Continued)
Page
6-5 Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations 140
6-6 NPDES Effluent Limitations for Treated Groundwater 145
6-7 Discharge Limitations 147
6-8 Effluent Treatment Levels for Beneficial Reuse
Discharges to Land for Irrigation Purposes 148
Travis AFB Groundwater IROD Vll as of 3 December 1997
-------
LIST OF ACRONYMS AND ABBREVIATIONS
AFB Air Force Base
AFCEE Air Force Center for Environmental Excellence
ARARs Applicable or Relevant and Appropriate Requirements
BAAQMD Bay Area Air Quality Management District
bgs below ground surface
Cal-EPA California Environmental Protection Agency
CE Civil Engineering
CERCLA Comprehensive Environmental Response, Compensation, and Liability
Act of 1980
CFGC California Fish and Game Code
COCs Contaminants of concern
COPECs Contaminants of Potential Ecological Concern
CPT Cone Penetrometer Testing
CRP Community Relations Plan
CTVs Critical Toxicity Values
DAA Detailed Analysis of Alternatives
DCA Dichloroethane
DCE Dichloroethene
DNAPLs Dense Non-Aqueous Phase Liquids
Travis AFB Groundwater IROO
V1H
as of 3 December 1997
-------
LIST OF ACRONYMS AND ABBREVIATIONS (Continued)
DTSC
EIOU
ERA
FFA
FS
FTA
gpm
HQ
HRA
HWCL
IRG
IROD
IRP
ISA
JFSA
LLNL
LNAPL
MAC
Department of Toxic Substances Control
East Industrial Operable Unit
Ecological Risk Assessment
Federal Facilities Agreement
Feasibility Study
Fire Training Area
gallons per minute
Hazard Quotient
Health Risk Assessment
Hazardous Waste Control Law
Interim Remediation Goal
Interim Record of Decision
Installation Restoration Program
Initial Screening of Alternatives
Jet Fuel Spill Area
Lawrence Livermore National Laboratories
Light Non-Aqueous Phase Liquid
Military Airlift Command
Travis AFB Groundwater IROD
IX
as of 3 December 1997
-------
LIST OF ACRONYMS AND ABBREVIATIONS (Continued)
MAP
MATS
MCL
MEK
msl
MW
NAAP
NCP
NEWIOU
NOU
NPDES
O&M
OSA
OU
OWS
P2 MAP
PAH
PCB
Management Action Plan
Military Air Transport Services
Maximum Contaminant Level
methyl ethyl ketone
micrograms per liter
mean sea level
monitoring well
Natural Attenuation Assessment Plan
National Contingency Plan
North, East, and West Industrial Operable Unit
North Operable Unit
National Pollution Discharge Elimination System
Operation and Maintenance
Oil Spill Area
operable unit
Oil/Water Separator
Pollution Prevention Management Action Plan
Polycyclic Aromatic Hydrocarbon
polychlorinated biphenyl
Travis AFB Groundwater IROD
as of 3 December 1997
-------
LIST OF ACRONYMS AND ABBREVIATIONS (Continued)
PCE
PCWQCA
POCOS
POTW
PP
ppb
PRG
RAB
RAOs
RCRA
RD/RA
RI
RME
ROD
SAC
SARA
SFBRWQCB
SIP
SSA
tetrachloroethene
Porter-Cologne Water Quality Control Act
Petroleum-Only Contaminated Sites
Publicly Owned Treatment Works
Proposed Plan
parts per billion
Preliminary Remediation Goal
Restoration Advisory Board
Remedial Action Objectives
Resource Conservation and Recovery Act
Remedial Design/Remedial Action
Remedial Investigation
Reasonable Maximum Exposure
Record of Decision
Strategic Air Command
Superfund Amendments and Reauthorization Act of 1986
San Francisco Bay Regional Water Quality Control Board
State Implementation Plan
Solvent Spill Area
Travis AFB Groundwater IROD
XI
as of 3 December 1997
-------
LIST OF ACRONYMS AND ABBREVIATIONS (Continued)
SSRW Storm Sewer Right of Way
SVE Soil Vapor Extraction
SVOC semivolatile organic compound
SWRCB State Water Resources Control Board
TARA Tower Area Removal Action
TBC To Be Considered
TCE Trichloroethene
TPH Total Petroleum Hydrocarbon
TPH-E Total Petroleum Hydrocarbon - extractable
TPH-G Total Petroleum Hydrocarbon - gasoline
TSDF treatment, storage or disposal facility
USAF United States Air Force
U.S. EPA United States Environmental Protection Agency
USTs Underground Storage Tanks
UV-OX ultraviolet radiation and oxidation
VOC volatile organic compound
WABOU West/Annexes/Basewide Operable Unit
WIOU West Industrial Operable Unit
Travis AFB Groundwater IROD
Xll
as of 3 December 1997
-------
PART I: DECLARATION
Site Name and Location
Department of the Air Force
Travis Air Force Base
Fairfield, California 94535-5000
Statement of Basis and Purpose
This Interim Record of Decision (IROD) presents the interim remedial actions for
groundwater in the North, East, and West Industrial Operable Units (NEWIOU) at Travis Air
Force Base (AFB or the Base) Superfund site in Solano County, California. The Air Force will
develop a separate Record of Decision (ROD) to address NEWIOU sites with soil, sediment,
and/or surface water contamination. The Air Force selected the interim remedial actions
evaluated in the Groundwater IROD in accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act of 1980 (CERCLA) as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA) 42 USC § 9601 et seq., and with the
National Oil and Hazardous Substances Pollution Contingency Plan, 40 CFR Part 300 (National
Contingency Plan [NCP]). The Administrative Record identifies the documents used in the
selection of the interim remedial actions. The Administrative Record is available for review at
Travis AFB.
The U.S. Environmental Protection Agency (U.S. EPA), Region IX, concurs with the
selected interim remedies. The State of California, through the California Environmental
Protection Agency's Department of Toxic Substances Control (Cal-EPA/DTSC) and the San
Francisco Bay Regional Water Quality Control Board (SFBRWQCB), concurs with the selected
interim remedies.
Travis AFB Groundwater IROD 1 as of 3 December 1997
-------
Assessment of the Site
Releases of volatile organic compounds (VOCs), semivolatile organic compounds
(SVOCs), polychlorinated biphenyls (PCBs), dioxins, and metals have contaminated the
groundwater at 15 sites within the NEWIOU at Travis AFB as a result of historic Base activities.
Actual or possible releases of hazardous substances from these sites, if not addressed by
implementing the response actions selected in the Groundwater IROD, may present a threat to
public health and welfare, or to the environment.
Rationale for Interim ROD
The Air Force has developed interim remedial actions to address groundwater
contamination in the NEWIOU. The Air Force has decided to prepare an IROD for groundwater
sites rather than a final ROD in order to allow remediation of groundwater to begin quickly to
reduce contamination and risk. The IROD establishes a five-year interim period after which a
final ROD will establish the final remedial actions and final cleanup levels. The Air Force will
use information from the interim remedial actions to allow for the selection of final cleanup
levels and technically and economically feasible long-term actions under a final groundwater
ROD. The Air Force will publish a public notice, hold a public comment period, and address the
public's comments before the regulatory agencies finalize and approve the groundwater ROD.
The Air Force will complete a separate Proposed Plan (PP) and ROD for soil, sediment,
and surface water sites in the NEWIOU.
Description of the Selected Interim Remedies
The Air Force considered three potential interim remedial alternatives to address
contaminated groundwater in the NEWIOU: 1) Alternative 1 (No Action); 2) Alternative 2
(Natural Attenuation/Monitoring); and 3) Alternative 3 (Extraction, Treatment, and Discharge).
Travis AFB Groundwater IROD 2 as of 3 December 1997
-------
The Air Force has selected interim remedial alternatives for 13 of the 15 sites \vith
groundwater contamination in the NEWIOU. The Air Force selected Alternative 1 (No Action)
for none of the sites. The Air Force selected Alternative 2 for one site (LF006), and Alternative 3
for seven sites. At five sites, the Air Force has selected Alternative 3 for a portion of the plume
and deferred the alternative selection for the remaining portion. These five sites require
additional characterization to determine if Alternative 2 or 3 is the most appropriate remedial
alternative. At two sites, the Air Force will defer the selection of an alternative for the entire
groundwater plume until the final ROD; the Air Force will perform additional characterization
during the five-year interim period. The following table summarizes selected interim remedial
alternatives:
Selected Alternative
Alternative 2
Alternative 3
Alternative 3 and portion of plume remedy deferred
Alternative selection deferred until final ROD
Total sites that will be addressed in the final ROD
No. of Sites
1
7
5
2
Site Names
LF006
FT004, FT005, SS029, SS030,
SD034, SD036
LF007, SS016, ST032, SD033,
SD031,
SD037
SS015, SS035
15
The Air Force chose the selected interim remedies, from many alternatives, as the best
methods for containing, monitoring, and treating contaminated groundwater in the NEWIOU.
These remedies address the potential risks to human health and the environment that could result
from exposure to groundwater by human (e.g., workers and residents) and ecological (e.g..
aquatic) receptors.
Based on the RI/FS, the Air Force has selected the most appropriate altemative(s) to
*
reduce the potential risk at each site. The Air Force selected Alternative 3 (Extraction, Treatment,
and Discharge) for all or part of 12 of the 15 groundwater sites in the NEWIOU (see Table 5-3).
Travis AFB Groundwater 1ROD
as of 3 December 1997
-------
For the remaining sites or portions of sites where Alternative 3 was not selected, the Air
Force considered Alternative 2 (Natural Attenuation/Monitoring) as a possible interim action.
The Air Force selected Alternative 2 for one site and deferred the selection of alternatives for the
remaining sites.
The Air Force will submit a Groundwater NEWIOU Remedial Design/Remedial Action
(RD/RA) Work Plan to the regulatory agencies for approval. The Groundwater NEWIOU
RD/RA Work Plan will be a primary document according to the Federal Facilities Agreement
(FFA). This Work Plan will provide a description of the overall rationale for treatment and
discharge of extracted groundwater for all groundwater sites in the NEWIOU, and will include
the RD/RA schedule and a decision matrix for selecting the treatment technologies at each site.
The Air Force will provide an opportunity for public participation during the Remedial Design
phase.
The Air Force will also submit a Natural Attenuation Assessment Plan (NAAP) to the
regulatory agencies for approval. The NAAP will be a primary document according to the FFA
and will include a schedule. A Natural Attenuation Decision Matrix will be included which will
outline the method to determine which sites and/or portions of plumes are appropriate for
remediation by natural attenuation (Alternative 2). In reference to the five sites where a portion
of the plume is Alternative 3 and a portion has the alternative selection deferred, the NAAP will
clearly explain the methodology to determine where Alternative 2 and Alternative 3 will be
applied. Where the selection of an alternative is deferred for the entire site, the NAAP will
describe the Air Force approach for evaluating natural attenuation. The NAAP is described in
more detail in Section 5.0 (Alternative 2) and Appendix B.
In addition to the Groundwater NEWIOU RD/RA Work Plan, the Air Force will
prepare a site-specific RD/RA work plan for each groundwater site within the NEWIOU. The
site-specific RD/RA work plans will include details for monitoring and evaluation based on site-
specific conditions. Each work plan will address placement of monitoring wells, protocols and
frequency for monitoring, and evaluation procedures for determining if migration above water
quality objectives is occurring. The agencies will review each of the site-specific RD/RA work
Travis AFB Groundwater IROD 4 as of 3 December 1997
-------
plans. If a contingency action is necessary to control migration, the Air Force will not wait until
the end of the five-year interim period. The Air Force will request funding and implement the
contingency action as soon as funding becomes available.
There is potential for contaminated groundwater to migrate along storm sewer lines and
other preferential pathways. The Air Force will implement Alternative 3 at some sites to control
migration of contaminated groundwater along preferential pathways. At other sites where the Air
Force has deferred the remedy selection until the final ROD, the Air Force will employ
monitoring and a contingency plan to ensure that preferential migration does not occur. At all
sites with known or potential interface between the storm sewer and contaminated groundwater,
the Air Force will investigate the interface during the Remedial Design (RD). At locations where
the Air Force has found the contaminated groundwater to be migrating to the storm sewer or
creek, the Air Force will use an interim remedial action such as pump and treat to control
migration. Where pump and treat is used, the Air Force will monitor the effectiveness of this
action; if the Air force finds that the pump and treat action is not adequately controlling the
migration, the Air Force will initiate a contingency action such as repair or lining of the storm
sewer.
The Air Force will implement interim remedial actions in accordance with the
Groundwater IROD. The Air Force will monitor all sites, including those proposed for natural
attenuation, and will evaluate the change in contaminant concentrations during the five-year
interim period. The Air Force will utilize the monitoring results to evaluate the potential for
natural attenuation under conditions present at Travis AFB. The Air Force and U.S. EPA are
developing the protocol for monitoring the natural attenuation of chlorinated compounds. The
Air Force and agencies will periodically review and evaluate data obtained from these actions to
determine the effectiveness of the action(s) and the need for additional action(s). Five years after
signing the IROD, the Air Force and agencies will hold a formal review. The Air Force and the
agencies will use the information obtained to determine final remedial actions and cleanup levels
that are technically and economically feasible at that time.
Travis AFB Groundwater IROD 5 as of 3 December 1997
-------
Declaration
These interim actions are protective of human health and the environment, are
compliant with Federal and State Applicable or Relevant and Appropriate Requirements
(ARARs) directly associated with these actions, and are cost-effective. These actions utilize
permanent solutions and alternative treatment (or resource recovery) technologies to the
maximum extent practicable given the limited scope of the action. This action does not constitute
the final remedy for groundwater at the Travis AFB NEWIOU sites. The Air Force and the
agencies will address the statutory preference for remedies which reduce toxicity, mobility, or
volume as a principal element at the time of the final groundwater ROD. The Air Force will base
subsequent actions on the knowledge and experience gained during the interim action. Any
future actions will fully address the principal threats posed by contaminated groundwater in the
NEWIOU at Travis AFB.
Travis AFB Groundwater IROD 6 as of 3 December 1997
-------
Lead and Support Agency Acceptance
of the Interim Record of Decision for Ground water
Travis Air Force Base, NEWIOU
This signature sheet documents agreement between the United States Air Force and the United
States Environmental Protection Agency and the State of California, by the California
Environmental Protection Agency, Department of Toxic Substances Control, and the San
Francisco Bay Regional Water Quality Control Board on the Interim Record of Decision for
groundwater in the NEWIOU at Travis Air Force Base. This sheet may be signed in counterparts
by the respective parties.
A/f
I2./3/97
Dan Opalski / ~ Date
Chief
Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency, Region K
Anthony J. Landis, P.E. Date
California Environmental Protection Agency
Department of Toxic Substances Control
Chief of Operations
Office of Military Facilities
Loretta K. Barsamian Date
San Francisco Bay Regional Water Quality Control Board
Executive Officer
John B. Sams, Jr. Date
Lieutenant General, USAF
Air Mobility Command
Chairperson, Environmental Protection Committee
Travis AFB Groundwaier IROD / as of 3 December 1997
-------
Lead and Support Agency Acceptance
of the Interim Record of Decision for Groundwater
Travis Air Force Base, NEWIOU
This signature sheet documents agreement between the United States Air Force and the United
States Environmental Protection Agency and the State of California, by the California
Environmental Protection Agency, Department of Toxic Substances Control, and the San
Francisco Bay Regional Water Quality Control Board on the Interim Record of Decision for
groundwater in the NEWIOU at Travis Air Force Base. This sheet may be signed in counterparts
by the respective parties.
Dan Opalski
Chief
Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency, Region IX
Date
Anthony J. Landis, P.E.
California Environmental Protection Agency
Department of Toxic Substances Control
Chief of Operations
Office of Military Facilities
Date
Loretta K. Barsamian
San Francisco Bay Regional Water Quality Control Board
Executive Officer
Date
John B. Sams, Jr.
Lieutenant General, USAF
Air Mobility Command
Chairperson, Environmental Protection Committee
Date
Travis AFB Groundwater IROD
8
as of 3 December 1997
-------
Lead and Support Agency Acceptance
of the Interim Record of Decision for Ground-water
Travis Air Force Base, NEWIOU
This signature sheet documents agreement between the United States Air Force and the United
States Environmental Protection Agency and the State of California, by the California
Environmental Protection Agency, Department of Toxic Substances Control, and the San
Francisco Bay Regional Water Quality Control Board on the Interim Record of Decision for
groundwater in the NEWIOU at Travis Air Force Base. This sheet may be signed in counterparts
by the respective parties.
Dan Opalski Date
Chief
Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency, Region IX
Anthony J. Landis, P.E. Date
California Environmental Protection Agency
Department of Toxic Substances Control
Chief of Operations _,,.-_„
Office of Military Facilities CAUf ORNIA REGIONAL WATER
OCT 0 3 15S7
I, * OUAirTv CONTROL 50A*L-
It. /*!>-
Lorerta K. Barsamian Date
San Francisco Bay Regional Water Quality Control Board
Executive Officer
John B. Sams, Jr. Date
Lieutenant General, USAF
Air Mobility Command
Chairperson, Environmental Protection Committee
Travis AFB Groundwater IROD 9 as of 3 December 1997
-------
Lead and Support Agency Acceptance
of the Interim Record of Decision for Ground water
Travis Air Force Base, NEWIOU
This signature sheet documents agreement between the United States Air Force and the United
States Environmental Protection Agency and the State of California, by the California
Environmental Protection Agency, Department of Toxic Substances Control, and the San
Francisco Bay Regional Water Quality Control Board on the Interim Record of Decision for
groundwater in the NEWIOU at Travis Air Force Base. This sheet may be signed in counterparts
by the respective parties.
Dan Opal ski
Chief
Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency, Region IX
Date
Anthony J. Landis, P.E.
California Environmental Protection Agency
Department of Toxic Substances Control
Chief of Operations
Office of Military Facilities
Date
Loretta K. Barsamian
San Francisco Bay Regional Water Quality Control Board
Executive Officer
Date
33
JohrVJl. Sams, Jr.
Lieutenant General, USAF
Air Mobility Command
Chairperson, Environmental Protection Committee
Date
Travis AFB Groundwuer IROD
10
as of 3 December 1997
-------
PART II: DECISION SUMMARY
The Decision Summary includes findings, evaluations, decision-making process, and
selected actions for the North, East, West Industrial Operable Unit (NEWIOU) Groundwater
Interim Record of Decision (IROD). Section 1.0 describes features of Travis Air Force Base
(AFB) including topography, climate, land use, ecology, geology, and hydrology. Section 2.0
provides an overview of non-Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) and CERCLA environmental programs at Travis AFB. Section 3.0
summarizes the nature and extent of contamination as presented in the North Operable Unit
(NOU) Remedial Investigation (RI), East Industrial OU (EIOU) RI, and West Industrial OU
(WIOU) RI. Section 4.0 presents a summary of the NEWIOU Feasibility Study (FS). Section 5.0
identifies the selected interim remedies and rationale. Section 6.0 presents the applicable or
relevant and appropriate requirement and performance standards for the interim actions.
Section 7.0 is the list of references.
This Decision Summary provides an overview of the NEWIOU, the groundwater
contaminants, and the areas considered for interim remedial response. The interim remedial
alternatives considered and the analysis of those alternatives compared to the criteria set forth in
the National Contingency Plan (NCP) are presented. This Decision Summary explains the
rationale for selecting the interim remedies and how the statutory requirements of the CERCLA
have been met.
1.0 NEWIOU DESCRIPTION
Travis AFB, located between Sacramento and San Francisco (see Figure 1-1), was
established in 1943. Travis AFB rapidly grew into the largest military aerial port, ferrying troops
and materials from California to the Pacific during World War II and the Korean conflict. The
base was used from 1948 to 1958 as a base for the Strategic Air Command (SAC). SAC
relinquished control of the base to Military Air Transport Services (MATS) in 1958, which
Travis AFB Groundwater IROD 11 as of 3 December 1997
-------
Santa Rosa Vacaville
[/
Fairfield .X^Travis
TRAVS897.FH3 - VMS 8/13/97 SAC
Figure 1-1. Regional Location Map, Travis AFB
Travis AFB Groundwater IROD
12
as of 3 December 1997
-------
established the headquarters for the Western Transport Air Force at Travis AFB. MATS evolved
into the Military Airlift Command (MAC) in the early 1960s. MAC was renamed the Air
Mobility Command in June 1992.
Travis AFB is part of the Air Mobility Command and is home to the 60th Air Mobility
Wing. The Air Mobility Wing operates C-5 and C-141 aircraft and KC-10 aerial refueling
aircraft and is the largest mobility organization in the Air Force, incorporating both MAC and
SAC units. The Air Force may redeploy additional units to Travis AFB as other bases undergo
realignment and closure.
Figure 1-2 shows the boundaries of the four operable units at Travis AFB. The NOU,
the EIOU, and W1OU comprise the NEWIOU. This IROD addresses groundwater contamination
within the NEWIOU. Soil, sediment, and surface water in the NEWIOU will be addressed in a
subsequent ROD. The fourth operable unit, the West/Annexes/Base wide Operable Unit
(WABOU), is not covered by this Groundwater IROD for the NEWIOU, and will be covered in a
separate IROD, which will be completed at a later date. The Travis AFB National Priorities List
(NPL) site includes two annexes, Annex 6 and Annex 10, that are part of the WABOU (see
Figure 1-3).
1.1 Physical Description
Topography at Travis AFB is characterized by a sloping to flat surface with variations
in topographic expression up to 50 feet. Elevations at Travis AFB range from over 100 feet
above mean sea level (msl) near the northern boundary to less than 20 feet above msl near the
south gate. The ground surface generally slopes to the south or southeast at about 30 feet per mile
(slope 0.6%) (Weston, 1992). The hills north of Travis AFB have a vertical relief of
approximately 110 feet. The hills south of Travis AFB reach elevations of approximately
400 feet above msl. The areas to the west, northwest, northeast, east, and south of Travis AFB
are nearly flat.
Travis AFB Groundwater IROD 13 as of 3 December 1997
-------
4
M
NORTH
OPERABLE
UNIT
J . \
Dose Housing
(No Detail Shown)
i •._/
•*«"«wt jj C»~~.ert ».. I „„,.„
DAVID CHAMP
MLUICAJ. CI
EAST
INDUSTRIAL
OPERABLE
UNIT
WEST/
ANNEXES/
BASE WIDE
OPERABLE
UNIT
.Ai.c in ' r< i
Figure 1-2. Travis AFB and Operable Units
-------
3
K'
3
o
3
a
§
o
e
o
?r
i
N
0 2
Scale in Miles
.,(80)
/
1
Vacaville
Fairlield
Cypress Lakes
> Golf Course
(Annex 10)
Travis AFB
—.-(12)
Potrero Hills
• (Annexe)
Figure 1-3. Travis AFB/Major Annexes Location Map
-------
Central California is characterized by wet winters and dry summers. The mean annual
temperature at Travis AFB is 60 degrees Fahrenheit (°F); the mean monthly temperatures range
from 46°F during December and January to 72°F during July, August, and September. The mean
annual precipitation is 17.5 inches with an average annual evaporation rate of 47 inches.
Approximately 85% of the precipitation falls between November and March. The prevailing
wind direction is from southwest to northeast, although wind directions vary throughout the year.
The mean annual wind speed is 8 knots, with the greatest monthly wind speeds typically
occurring from May through August. The monthly relative humidity ranges from a high of 77%
during January to a low of 50% during June (Weston, 1995a).
1.2 Land Use
Travis AFB occupies approximately 5,025 acres of land near the center of Solano
County, California, and is approximately 3 miles east of downtown Fairfield and 8 miles south of
downtown Vacaville (see Figure 1-3). Travis AFB consists of five types of land uses:
• Industrial support areas;
• Air field or direct mission areas;
• Administrative and medical service areas;
• Housing, recreation, and service areas; and
• Open space areas.
The lands surrounding Travis AFB are primarily used for ranching and grazing, with
some light industrial activity present to the northwest. The estimated populations of Fairfield,
Vacaville, and nearby Suisun City are 85,560, 85,000, and 23,560, respectively. The projected
population growth between 1990 and 2000 is 47.4 % for the City of Fairfield and 33.6% for
Solano County (Weston, 1995a). Approximately 3,700 military personnel and 4,400 family
Travis AFD Groundwater IROD 1 6 as of3 December 1997
-------
members live on Travis AFB. In addition, 3,172 civilians are employed at the base.
Approximately 17,000 people are on Travis AFB daily (Weston, 1995a).
1.3 Ecology
The Air Force conducted a special-status species survey at Travis AFB in 1993
(BioSystems Analysis, 1992; BioSystems Analysis, 1993). This survey characterized habitats
and identified special-status species on contaminated sites at the base. Four general habitats have
been identified at Travis AFB:
Disturbed herbaceous-dominated grasslands containing a mixture of native and
non-native grasses and ruderal vegetation;
Developed areas including lawns, landscaping trees and shrubs, barren areas,
and paved areas;
Permanent and temporal natural pools; and
Riparian and wetland habitat (main branch of Union Creek and portions of the
west branch of Union Creek).
Surface features of the base include creeks, drainages, buildings, paved areas, and small
amounts of grassland. Most of the land at Travis AFB is covered by buildings or paved areas, but
several natural and artificial wetlands exist there as well. Wetlands include Union Creek and the
vernal pools (i.e., seasonal ponds) in the NOU and WIOU.
The Air Force identified several special-status species at Travis AFB (BioSystems
Analysis, 1992; BioSystems Analysis, 1993; and Weston, 1995b). These species include:
• the black-shouldered kite (Elanus caerleus);
• the Boggs Lake dodder (Cuswata howelliand);
Travis AFB Groundwater IROD 17 as of 3 December 1997
-------
• the burrowing owl (Speotyto cunicularid);
• the Cooper's hawk (Accipter cooperii);
• the California gull (Larus californicus);
• the golden eagle (Aquila chrysaetos);
• the loggerhead shrike (Lanius ludovicianus);
• the northern harrier (Circus cyaneus);
• the red fox (Vulpes vulpes);
• the tricolor blackbird (Agelaius tricolor);
• the vernal pool fairy shrimp (Branchinecta lynchi);
• the Contra Costa goldfields (Lasthenia conjugens);
• the Northwestern pond turtle (Clemmys hammondi hammondi)\
• the San Joaquin spearscale (Atriplex joaquiniand);
• the round wooly-marbles (Psilocarpthus tenellus var. globiferous);
• the alkali milkvetch (Astragalas tener var. tener);
• the San Francisco forktail damselfly (Ischnura gemind); and
• the vernal pool tadpole shrimp (Lepidurus packardi).
Other special-status species may have the potential to occur at Travis AFB, but were not
identified during surveys.
Travis AFB Groundwater IROD 18 as of 3 December 1997
-------
1.4 Geology and Hydrogeologv
The basewide topography, and regional and local geologic and hydrogeologic
conditions of Travis AFB are described to provide a basis for predicting the migration of
contaminants in the subsurface. Geologic and hydrogeologic conditions control the movement of
water and contaminants through the subsurface. The respective RIs for each of the three operable
units present in greater detail the geology and hydrogeology of the individual facilities within the
NEWIOU.
1.4.1 Geology
Travis AFB is located near the western boundary of the Central Valley Physiographic
Province of California (Weston, 1992). The California Central Valley is a sediment-filled
synclinal basin with a northwest-to-southeast oriented axis. The Coast Range Physiographic
Province west of Travis AFB generally consists of folded and uplifted bedrock.
Figure 1 -4 is a geologic map and generalized cross-section illustrating the shallow
bedrock units and alluvium in the area surrounding Travis AFB. Table 1-1 is a geologic column
that summarizes the characteristics of the shallow bedrock and alluvium. Bedrock units
recognized in the vicinity of Travis AFB include (from oldest to youngest) the Domengine
Sandstone, the Nortonville Shale, the Markley Sandstone, and the Neroly Sandstone. The surface
trace of the Vaca Fault has been mapped from northwest to southeast across Travis AFB.
Past tectonic processes folded and uplifted the bedrock to form the hills and mountains
located north, west, and south of Travis AFB. The alluvium in the vicinity of Travis AFB
originated from the erosion of the elevated bedrock formations and subsequent deposition in
various continental environments.
Travis AFB Groundwater IROD 19 as of 3 December 1997
-------
Qoel
/ - ^ w- - x^~\ "*
I ./"...':'J ~ ^ ( N SoatohMtes /,.. ... £; •-"^'ai- -••-•• '^
Modified from USGS map by F.K amsted, etal..JMO-S1. Strike and dip information (rorn RactorTfield data.,
Plan View
VacaFautt QD.I
sw
Base
R Boundary
NE
Base
Boundary p>
&ppm. XS iritos
Conceptual Cross Section
LEGEND:
See text for further
: types.
Strike and Dip
-A—> AnttclineAxte
Younger Alluvium
Older Aluvium
UndWerentiated Sandstones, Stftstones, and *
Shales, including the Markley Sandstone, t'
Nortonvtte Shale, and Domengine Sandstone *
UndHferontiatod Rodo, c<>. * -»--•—^ u^jum
including the Tehama Formation ^£&!%£F
where buried.
Figure 1-4. Geological Map of Travis AFB and Vicinity
Travis AFB Groundwtter IROD
20
as of 3 December 1997
-------
I
Table 1-1
Geologic Column - Travis AFB and Vicinity, California
Million Years
Before Present
1.8
5
55
Geologic
Period
Quaternary
Tertiary
Cretaceous
Geologic
Epoch
Holocene
Pleistocene
Pliocene
Miocene
Eocene
-
Geologic
Unit
Alluvium (Q y,,)
Older Alluvium (Q „,)
Tehama Formation (Tt)
Neroly Sandstone
Markley Sandstone (Tmk)
Nortonville Shale (Tn)
Domengine Sandstone (Td)
Guinda Formation (Kg)
Description
Poorly-sorted stream and basin
deposit clay to boulder size.
Dissected alluvial deposits.
Sand, silt rocks. Volcaniclastic.
Interbedded sandstone, siltstone,
and shale.
Massive, brownish-gray,
Feldspathic, Micaceous
sandstone.
Dark brown, silty shale,
interbedded with sandstone.
Quartzose sandstone, basal
glauconite grit.
Massive sandstone with
calcareous concretions and
interbedded shale.
Environment of
Deposition
Continental
Continental
Continental
Marine
Marine
Marine
Marine
Marine
R
o
8
I
i
Source: California Division of Mines and Geology. Regional Geologic_Sacramento Quadrangle_Map No. IA 1981.
Also see: Marchard, D.E., and Allwardt, A. 1977, Late Cenotoic Straligrophic Units Nonhtasiern San Joaquin Valley, California, U.S. Geologic Survey open file. Report number 77-748.
136 p.
-------
Rock grains and fragments eroded from the Coast Ranges were deposited as alluvial
sediment units by Putah, Ulatis, Alamo, Laurel, Suisun, and Union Creeks. The parent rocks for
the alluvium at Travis AFB include metasediments, serpentinites, ultramafic rocks, and the
Sonoma Volcanics (Olmsted and Davis, 1961; Wagner, 1982). The alluvium is divided into units
of older and younger alluvium. At Travis AFB, the thickness of the alluvium ranges from 0 feet
to approximately 70 feet. West of Travis AFB, the thickness of the alluvium increases to over
200 feet (Weston, 1992; Thomasson et al, 1960).
Outcrops of the relatively resistant Markley and Domengine Sandstones form most of
the topographic high points on the base including the hill at the old base hospital, the low ridge
along the boundary between the WIOU and the EIOU near the center of Travis AFB, and the
hills north of Travis AFB. Erosion of the less resistant bedrock units, such as the Nortonville
Shale, formed low areas that were later filled with alluvium. Three major subsurface bedrock
ridges have been identified in the EIOU: the Eastern Ridge, the Central Ridge, and the Western
Ridge (Weston, 1995a). These areas have bedrock at 20 feet below ground surface (bgs) or less.
The three ridges are anticlines which plunge slightly towards the south - as does the surface
elevation in these areas. The Vaca Fault runs through the Central Ridge in a south-southeastern
direction. The material between these anticlines is alluvium — predominantly silts and clays with
intermittent sand lenses. The Western Ridge bisects the EIOU and the WIOU. The bedrock
consists of poorly to moderately indurated (cemented) sandstone.
Travis AFB is located in an alluvial fan extending from the Vaca Mountains (located
north of Travis AFB) to the Suisun Marsh. Sediment eroded from the Vaca Mountains has been
carried in several streams (including the West Branch of Union Creek) which have migrated
laterally across the Base. Deposition of alluvium usually occurs during floods. Coarse sands and
gravels are deposited immediately adjacent to the stream levee; finer silts and clays are carried
much further. Consequently, the intermittent sand lenses are usually elongated parallel to the
stream. Sand lenses throughout Travis AFB trend south-southeast (Weston, 1995a).
Travis AFB Ground water I ROD 22 as of 3 December 1997
-------
1.4.2 Hydrogcology
Travis AFB is located at the eastern edge of the Fairfield-Suisun hydrogeologic basin.
The Fairfield-Suisun Basin is a hydrogeologically distinct structural depression adjacent to the
Sacramento Valley segment of the Central Valley Province (Weston, 1992; Thomasson et al,
1960).
The hydrogeologic basin is bordered to the north by the Vaca Mountains and to the east
by the ridge which runs along the eastern portion of the NOU and EIOU. The basin slopes south
into the Suisun Marsh (Thomasson et al, 1960); consequently, most groundwater and surface
water at Travis AFB flows south toward Suisun Marsh. For example, both the West Branch of
Union Creek and Storm Sewer Systems II and III empty surface waters and storm runoff into
Union Creek which ultimately discharges into the marsh.
Within Travis AFB, the Fairfield-Suisun Basin can be further divided into three
subbasins which are bordered by subsurface ridges of low permeability bedrock - sandstones and
siltstones. The hydrological subbasins are alluvial-filled depressions. These depressions are
composed predominantly of clay and silt with some intermittent sand lenses. The subbasins are
underlain by the Nortonville Shale (Weston, 1995a).
Coarse-grained sediments (sand and gravel) within the alluvium are the primary
water-bearing deposits in the region around Travis AFB. The bedrock units generally do not
yield groundwater of usable quantity or quality (Thomasson et al, 1960).
1.4.3 Groundwater Gradient and Flow
Groundwater recharge occurs from the direct infiltration of rainfall on the ground
surface and from the infiltration of runoff through depressions, and local creek beds. Natural
groundwater discharge may occur in the ditches and branches of Union Creek that flow into
Travis AFB Groundwater IROD 23 as of 3 December 1997
-------
Suisun Marsh, as well as directly into the marshlands located near the Potrero Hills, south of
Travis AFB (Thomasson et al, 1960). When the water table elevation is above the surface water
in areas with a high water table, discharge of groundwater occurs.
Depth to groundwater changes seasonally depending on the amount of rainfall and
subsequent infiltration. Thus at the end of the dry season, depths to groundwater are greater than
during the rainy season.
The groundwater gradient describes the differences in hydraulic potential and indicates
the direction of groundwater flow. The general direction of the groundwater gradient within the
alluvium at Travis AFB is southerly, similar to the regional gradient. However, local variations
(groundwater mounds and depressions) exist within the boundaries of Travis AFB. Alluvium is
between 0 to 70 feet thick and the hydraulic gradient is southerly throughout much of Travis
AFB. The groundwater contours are diverted from the southerly gradient in areas where alluvium
is thinner (i.e., the bedrock ridges). The change in gradient is due to the decreasing thickness of
the more permeable alluvium and the increasing thickness of the less permeable bedrock.
Figure 1-5 illustrates the bedrock ridges, alluvial valleys, and generalized groundwater
flow directions. The bedrock ridges bordering the subbasins are indicated by potentiometric
highs in the shallow groundwater elevation map. Bedrock highs, such as the old base hospital
(northern EIOU) and the TF33 Test Stand Area (western W1OU), have elevated groundwater
levels. These groundwater highs result from horizontal flow from the bedrock to the adjacent
alluvium, limited by the low permeability of bedrock (Radian, 1996b).
The maximum horizontal hydraulic gradient in the upper portion of the aquifer at Travis
AFB is approximately 0.02 (vertical foot per horizontal foot) at the groundwater mound near the
old base hospital. The minimum horizontal gradient in the upper portion of the aquifer is
approximately 0.002 near the southern border of Travis AFB. The average magnitude of the
Travis AFB Groundwater 1ROD 24 as of 3 December 1997
-------
_._._~ •* • ••'•'•
-' •"
•'^.' '' ': '•"'.,;,' CENTRA ' '" ' ••^"'
i •(: • . '•:' t. .
WEST V .
BASIN
west
BftMtCM Or
U«ON CRCCM ' '
•. .,-,•., sooisr
01010 • l' " " ' •'••'<'•' • •
O;HI «•.»!.••. i.i .••.»•. '.«*i
Fl»ur« 1-1
ll)'iirolo|lc OounJarlcl inJ
li«ojr«|'Mc Prcilniliy «f Sim
-------
groundwater gradient in the upper portion of the aquifer at Travis AFB is approximately 0.005.
The horizontal hydraulic gradients in the deep portion of the aquifer range from 0.01 to 0.003.
1.4.4 Aquifer Tests
The hydrogeologic parameters of hydraulic conductivity and porosity are needed to
calculate groundwater flow velocities. To define the hydrogeologic parameters of the alluvial
deposits and bedrock, aquifer slug tests and aquifer pumping tests were conducted at Travis AFB
between 1988 and 1991. In general, fine-grained material (e.g., clay and silt) are expected to
exhibit lower values of hydraulic conductivity than coarse-grained material (e.g., sand and
gravel).
Table 1-2 summarizes the range of calculated hydraulic conductivities of the major
geologic units based on the aquifer tests conducted at Travis AFB. Hydraulic conductivity
readings in the younger and older alluvium indicate the wide range of textures (i.e., grain sizes
and sorting) observed in these alluvial units. Hydraulic conductivity readings of the sandstone
and shale or siltstone bedrock also varied. Fewer tests were conducted on the bedrock units.
Bedrock test wells are generally screened in the upper portion of the bedrock units, which was
probably subject to weathering. This may have increased its permeability prior to being covered
by alluvium.
Significant overlap occurs in the range of hydraulic conductivities for each of the four
geologic units listed in Table 1-2. The average hydraulic conductivity of the sandstone bedrock
and the older alluvium vary by only a factor of 3. However, the range of measured hydraulic
conductivities varies greatly (Table 1-2), depending on the adjacent alluvium and bedrock at any
specific location.
Vertical hydraulic conductivities were calculated from aquifer pumping test data
collected at two locations (monitoring well [MWJ-245 and MW-214) within the EIOU. The
Travis AFB Groundwater IROD 26 as of 3 December 1997
-------
o
I
Q.
I
1
Table 1-2
Summary of Hydraulic Conductivity Values
Geologic
Unit
Younger Alluvium
Older Alluvium
(Vertical K)
Sandstone Bedrock
Shale or Siltstone Bedrock
Number
of Tests
9
30
(2)
2
4
Hydraulic Conductivity (ft/minute)
Minimum
0.0005
0.0001
(0.000121)
0.0025
0.0006
Maximum
0.079
0.074
(0.00229)
0.021
0.0415
Average
0.020
0.027
(0.0012)
0.0088
0.020
K)
R
o
Sources: Modified from Weston. 1990; Westun. 1992.
ft/minute => feet per minute
Vertical K = Vertical Hydraulic Conductivity
s
Sf
-------
vertical hydraulic conductivity in the EIOU ranged from 1.21 x 10"4 feet per minute to 2.29 x 10°
feet per minute. These tests were short-term tests; therefore, they reflect the hydraulic
conductivity near the pumping wells.
The lower hydraulic conductivities calculated for the vertical direction relative to the
horizontal direction indicate that groundwater will flow more easily horizontally than vertically.
If the ratio of horizontal to vertical hydraulic conductivity is approximately 100 or more,
groundwater flow will essentially be horizontal even in the presence of a vertical gradient
(Freeze and Cherry, 1979). Consequently, dissolved contaminants will also migrate horizontally,
through the more permeable units such as the alluvium and with minimal vertical migration into
the bedrock due to dispersion.
Groundwater velocities from a basewide perspective were estimated as part of the
NEWIOU FS (Radian, 1996a) based on gradients, aquifer test results, and literature values. The
velocities (ranging from 5 to 50 feet per year) were used in calibrating a model to estimate times
to cleanup. A velocity of 10 feet per year provided the best fit with the field data.
1.4.5 Regional Groundwater Use
Large volume pumping of groundwater generally occurs only to the west of Travis AFB
and in Fairfield where the alluvium is thicker and contains a greater abundance of coarse-grained
sediment. Groundwater wells in the area of Travis AFB are limited to domestic, stock-watering,
and irrigation wells. Domestic wells, several of which are downgradient from Travis AFB, are
typically used for households and gardens (Weston, 1995a). Groundwater contamination does
not affect domestic wells. Interim actions will be protective of these off-base wells. The
residences surrounding Travis AFB use groundwater for their domestic water supply because
there is no existing county water supply.
Travis AFB Groundwater 1ROD 28 as of 3 December 1997
-------
No on-base wells are currently used for potable water production. However, several
wells located 4 miles north of Travis AFB, at the golf course annex, produce 400 to 500 million
gallons of water per year. This well water is mixed with surface water purchased from the city of
Vallejo to supply potable water to Travis AFB. The Fairfield public water supply field is located
approximately 3 miles west of Travis AFB (Weston, 1995a). Groundwater contamination from
Travis AFB does not affect Fairfield's water supply; these interim actions will be protective of
Fairfield's wells.
1.4.6 Surface Water
Local drainage patterns have been substantially altered at the base by the rerouting of
Union Creek, the runway and apron construction, the installation of storm sewers and ditches,
and general development (e.g., industrial shops, maintenance yards, roads, and housing). Vernal
pools are present on base; the quality and specific locations are described in the Basewide
Ecological Habitat Survey (Weston, 1995b). Surface water at Travis AFB drains into several
storm sewer systems (or storm drains), a network of underground pipes, culverts, and open
drainage ditches, which directs surface water runoff and rainfall to Union Creek (Figure 1-6). In
general, drainage from the WIOU flows into the West Branch of Union Creek which flows into
Union Creek at Outfall II. Drainage from the EIOU flows into storm sewer systems which flow
into Union Creek at Outfall III. At the north end of the base, Union Creek flows into the duck
pond, through an underground piping system, resurfacing and flowing into Union Creek at
Outfall IV. Union Creek flows southwest and discharges into Hill Slough. Hill Slough is a tidal
wetland, approximately 1.6 miles south of the base boundary. Although some tributaries to Hill
Slough may be intermittent, the slough itself is a permanent, not seasonal, wetland. Surface water
from Hill Slough flows into Suisun Marsh, the largest contiguous estuarine marsh in the
continental United States, and a major wintering ground for migratory waterfowl (Weston,
1992). Surface water contamination will be addressed in the NEWIOU Soil, Sediment, and
Surface ROD which will be completed after the NEWIOU IROD is finalized.
Travis AFB Groundwater IROD 29 as of 3 December 1997
-------
WES1\BRANCH
OMOWyCBEEK
i S0036
Fipurc 1-6,
Location of On-Silc Surface
Water and Slorm Sewer Systems
Travis A Fll
JO
-------
2.0 OVERVIEW OF TRAVIS AFB ENVIRONMENTAL PROGRAMS
2.1 Non-CERCLA Environmental Programs
In addition to Travis AFB's efforts to investigate and remediate sites under the
CERCLA program, Travis AFB maintains an active environmental compliance program to
comply with a wide variety of non-CERCLA environmental regulations. This section briefly
discusses some of the more important non-CERCLA compliance programs.
2.1.1 Air Force Regulations and Management Action Plan
The Air Force has developed a parallel set of environmental regulations to the federal
environmental regulations. These Air Force regulations are designed to ensure that federal
requirements are implemented in an appropriate manner at Air Force installations. Air Force
regulation AFI 32-7005 sets up Environmental Protection Committees to oversee management of
all environmental programs. The following are examples of environmental compliance subject
areas where the Air Force has specific environmental regulations designed to parallel federal
environmental regulations:
• Environmental Restoration Program;
• Air Quality Compliance;
• Water Quality Compliance;
• Solid and Hazardous Waste Compliance;
• Storage Tank Compliance;
• Environmental Impact Analysis Process;
• Integrated Natural Resource Management;
Travis AFB Groundwater IROD 31 as of 3 December 1997
-------
• Cultural Resource Management; and
• Pollution Prevention Program.
The Management Action Plan (MAP) for Travis AFB (Parsons Engineering Science,
1996) summarizes the current status of the Travis AFB environmental restoration and associated
compliance programs, and presents a comprehensive strategy for implementing response action
necessary to protect human health and the environment. The Air Force produced the most recent
version of the MAP in January 1997. The MAP is used by Travis AFB environmental staff and
Air Force headquarters to direct and monitor environmental response action and to schedule
activities needed to resolve technical, administrative, and operational issues.
The Travis AFB Base General Plan, known as the Base Comprehensive Plan, a
companion document to the MAP, provides an organized, systematic, and comprehensive
approach to current and future planning and development. The Base General Plan is a tool that
addresses a multitude of installation requirements and assists in the long-range growth of the
base, including natural resources, environmental protection, land use, airfield operation, utilities,
transportation, and architectural compatibility. Of particular importance is its role in
environmental protection. The Plan requires addressing proper hazardous waste management and
recognizing CERCLA related activities, through proper land use at Travis AFB.
2.1.2 Resource Conservation Recovery Act and Hazardous Waste Management
Program
Travis AFB operates as a generator and facility for hazardous waste management under
the Resource Conservation Recovery Act (RCRA) and State of California hazardous waste
management programs. Travis AFB received a Part B hazardous waste facility storage permit
from the California Department of Toxic Substances Control Division (DTSC) and the United
States Environmental Protection Agency (U.S. EPA) on 5 March 1993.
Travis AFB Groundwater IROD 32 as of 3 December 1997
-------
2.1.3 Petroleum-Only Contaminated Sites Program (POCOS)
Travis AFB has a POCOS program designed to manage sites on base whose
contamination is limited to petroleum-related constituents. Travis AFB and the agencies agreed
to remove the POCOS from the Travis AFB CERCLA program because the law excludes
petroleum as a CERCLA contaminant. The Air Force will address petroleum contamination
under CERCLA if it is commingled with CERCLA contaminants.
POCOS are typically associated with surface and sub-surface releases from fuel spills,
piping leaks, oil-water separators, or underground storage tanks (USTs). The POCOS program
includes removal of leaking USTs and remediation of petroleum-only contaminated soil and
groundwater. The agencies and the Air Force delisted the North/South Gas Station site from the
CERCLA program; the site is now a POCOS. The North/South Gas Station is also a
demonstration site for the Lawrence Livermore National Laboratory for a natural attenuation
study. The San Francisco Bay Regional Water Quality Control Board (SFBRWQCB) is the lead
oversight agency for this program.
2.1.4 Storrmvater Discharge Permit
Travis AFB monitors stormwater outfalls in compliance with its state of California
National Pollution Discharge Elimination System (NPDES) permit. The ongoing monitoring
program was developed in 1992. The Air Force conducts sampling and reporting according to the
permit requirements. The SFBRWQCB is the lead oversight agency for stormwater discharges.
2.1.5 Pollution Prevention Program
Travis AFB has an active Pollution Prevention Program which strives to reduce the
generation of wastes through a hierarchy of actions. The actions range from the most preferred
choice of source reduction, to recycling, treatment, and finally disposal as a last resort. The
Travis AFB Groundwater IROD 33 as of 3 December 1997
-------
Pollution Prevention MAP (P2 MAP) defines the framework to accomplish these actions. The
plan analyzes all processes generating hazardous waste streams and performs opportunity
assessments of potential pollution prevention options to reduce the volume and/or toxicity of
generated wastes. This program includes minimizing wastes generated by sampling activities in
thelRP.
2.2 CERCLA Environmental Programs
This section summarizes the basic steps of the CERCLA process in Section 2.2.1. The
following section, Section 2.2.2, then discusses how the Air Force has implemented the
CERCLA process basewide at Travis AFB. Finally, Section 2.2.3 discusses what CERCLA
activities have been, and will be, performed within the NEWIOU.
2.2.1 CERCLA Process
CERCLA, passed in 1980, and amended by the Superfund Amendments and
Reauthorization Act (SARA) of 1986, was designed to establish a program to remediate sites
contaminated with hazardous constituents to protect public health and the environment.
2.2.1.1 General CERCLA Process, Remedial Investigation/Feasibility Study/Record of
Decision/Proposed Plan/Remedial Design/Remedial Action
CERCLA established a series of steps designed to investigate contamination at sites and
develop and implement appropriate remedial actions at these sites. The first key step is the Rl.
The RI serves as the mechanism for collecting data to characterize site conditions, to determine
the nature of the waste, and to assess risk to human health and the environment. The Air Force
generally collects data in several stages, with initial data collection efforts usually limited to
developing a general understanding of the site. As the Air Force achieves a basic understanding
of site characteristics, subsequent data collection efforts focus on filling identified gaps in the
Travis AFB Groundwater IROD 34 . as of 3 December 1997
-------
understanding of site characteristics and gathering information necessary to evaluate remedial
alternatives.
The FS serves as the mechanism for the development, screening, and detailed
evaluation of alternative remedial action. The FS consists of developing and screening of
potential technologies for treatment, containment, or disposal of contaminated media. The Air
Force then consolidates technologies into remedial alternatives. The Air Force then evaluates
each of the alternatives against nine CERCLA criteria within the categories of effectiveness, cost,
and implementability.
Following completion of the RI/FS process, the Air Force writes the Proposed Plan
(PP), which outlines the preferred alternative for each site(s). This document allows the public an
opportunity to comment on the preferred alternative and to gain an understanding of what
alternative is proposed for implementation and why the proposed alternative best fits the
problems at the site. After the public comment period, the Record of Decision (ROD) authorizes
the selected alternative. The ROD summarizes all CERCLA activities at the site and selects the
final remedial alternative. The ROD, which is signed by Travis AFB and the regulatory agencies,
formally documents concurrence of the selected alternative. A final ROD specifies the final
remedial alternative and establishes cleanup levels. An Interim ROD (IROD) does not specify
final cleanup levels or/and the final selected alternative. IRODs are designed to quickly
implement remedial actions to reduce contamination, reduce risk, and/or gather information that
can be used to adjust the approach down the road as needed to ensure protectiveness.
The remedial design/remedial action (RD/RA) process documents all activities after the
approval of the ROD or IROD, related to implementation of the selected alternative. The RD
specifies the engineering design of the alternative in much more detail than was presented in the
ROD or PP. The RA is the construction and operation of the selected alternatives specified in the
ROD and RD. The Air Force will submit a schedule for the RD/RA to the regulatory agencies
Travis AFB Groundwater IROD 35 as of 3 December 1997
-------
twenty-one days after the ROD or IROD is signed. The RD/RA schedule is described in
Section 5.4.
2.2.2 CERCLA Activities at Travis AFB
The Air Force, under the Installation Restoration Program (IRP), began an effort to
identify contaminated sites at Travis AFB in 1983. (The IRP is the Air Force program to address
CERCLA sites at bases.) After completing the Records Search and a Phase II study to confirm
problem areas, Travis AFB developed an integrated IRP Work Plan in 1986. The U.S. EPA
placed Travis AFB on the National Priority List in 1989. In 1993, the Air Force divided the site
into four specific OUs: the NOU, the EIOU, the WIOU, and the WABOU (Figure 1-2). The Air
Force made this division into separate OUs because each OU has different types of contaminant
sources (e.g., landfills in the NOU), contaminant types, and contaminated media (e.g., storm
drains in the WIOU and EIOU). Also, the very large geographic size of Travis AFB necessitated
that the contaminated areas be separated into OUs for efficiency and to focus the separate RIs.
The Air Force combined the NOU, EIOU, and WIOU into one FS to be more cost effective. The
FS for the NEWIOU is presented in the North, East, and West Industrial Operable Unit
Feasibility Study, (Radian, 1996a).
The Air Force has decided to prepare an IROD for NEWIOU sites with contaminated
groundwater (see Table 2-1) rather than a final ROD in order to speed up the site cleanup. This
IROD establishes a five-year interim period after which a final ROD will establish the final
remedial actions and final cleanup goals. The Air Force will publish a public notice and hold a
public comment period before the ROD is finalized and approved by the regulatory agencies. The
Air Force will prepare a separate final ROD for soil, sediment, and surface water in the
NEWIOU later.
Travis AFB Groundwater IROD 36 as of 3 December 1997
-------
Table 2-1
T)
Q.
s
§
o
Description of NEWIOU 1RP Sites with Groundwater Contamination
Operable Unit
NOU
E10U
IRPSite
LF006
LF007
FT004
FT005
SS015
SS016
SS029
SS030
SD03I
ST032
Activities Leading to Current Contamination
Landfill 1 was a general refuse landfill that used burn and fill disposal methods from 1943 through 1950.
Landfill 2 (Areas B, C, and D) was a general refuse landfill that used trench and fill methods from 1950 to 1973.
Fire Training Area 3. The Air Force used this area for fire fighting training exercises which burned waste fuels, oils, and
solvents on the open ground. The Air Force used the area from 1953 until 1962, reportedly.
Fire Training Area 4. The Air Force used this area for fire fighting training exercises from 1962 through 1987. Throughout
the 1960s, waste fuels, oils, and solvents were burned. From the early 1970s, the Air Force used only waste fuels for training.
Solvent Spill Area and Facilities 550 and 552. Solvent stripping of aircraft parts, aircraft maintenance and repair, oil/water
separator activities, and hazardous waste accumulation occurred in these areas. The primary chemicals used in these facilities
include thinners, methyl ethyl ketone, resins, and emulsifiers. The Air Force chemically stripped radomes of paint from 1964
to 1980 near Facility 552.
Oil Spill Area (OSA), Facilities 11, 13/14, 18,20,42/1941, 139/144, and selected sections of Storm Sewer Right of Way. Oil
spills, degreasing operations, leaking oil/water separators, equipment maintenance and repair, aircraft washing, hazardous
waste storage, vehicle maintenance, storm water run-off, and a wash rack are the principal contamination sources in these
areas. Chemicals handled include lubricating oils, hydraulic fluid, solvents, and water containing solutions of these
chemicals. The Air Force used the OSA from the 1940s through the 1980s. The Air Force used most of the facilities from the
1940s up to the present day.
Monitoring Well (MW) 329 Area. Unknown past activities contaminated the groundwater with trichloroethene (TCE).
MW-269 Area. Past practices near Facility 1 125 (a radar facility) may have released TCE to the subsurface at an unknown
time in the past. Possible sources include a leach field and/or surface disposal of TCE.
Facility 1205. Maintenance and repair of diesel powered generators, wash rack activities, and oil/water separator leaks
contributed to contamination at this site. Aerial photographs suggest that the Air Force may have used the area for aircraft
maintenance. The facility has handled oils, antifreeze, and solvents and has been in use from 1957 to the present.
Areas MW-107 and MW-246. Past fuel line leaks have contaminated the subsurface with fuel.
u>
-J
K
o
§•
i
-------
Table 2-1
CO
i1
I
§
Description of NEWIOU IRP Sites with Groundwater Contamination
(Continued)
Operable Unit
IRP Site
Activities Leading to Current Contamination
WIOU
SD033
SD034
00
SS035
SD036
SD037
K
o
Storm Sewer II, Facilities 810 and 1917, South Gate Area, and West Branch of Union Creek. The Air Force used these areas
to handle storm water runoff, fuel transport, aircraft maintenance, and aircraft washdown including wash racks and oil/water
separators. Chemicals used in these areas include fuels, lubricating oil, hydraulic fluids, chlorinated solvents, and soap
solutions. The Air Force constructed Facility 1917 in 1956, and the facility is no longer in use. Facility 810 was constructed
in 1955 and is currently used for aircraft maintenance.
Facility 811. An aircraft wash rack with oil/water separator and overflow pond have contributed to groundwater
contamination at this site. Chemicals used at this facility include acids, solvents, antifreeze and the Stoddard solvent
PD-680. The Air Force constructed this facility in 1979, and it is still in use.
Facility 818/819. Aircraft washing, painting and repair and oil/water separator activity have contributed to groundwater
contamination at this site. Chemicals used at these facilities include lubricating oil, hydraulic fluids, PD-680 and water
solutions of these chemicals. The Air Force constructed these facilities in 1970, and they are still in use.
Facilities 872/873/876. These facilities were constructed as multiple use shops which have included a wash rack and an
oil/water separator. Current uses of the facilities include paint shops, electrical shops, landscape maintenance, paint mixing,
and paint accumulation. Chemicals used include cleaning solutions, grease, degreasers, hydraulic oils and fluids, PD-680,
pesticides, paints, and solvents. The Air Force constructed the shops in 1953, and they are still in use.
Sanitary Sewer System, Facilities 837, 838, 919, 977, 981, Area G Ramp, and Ragsdale/V Area. These facilities include
handling of domestic and industrial waste water, aircraft maintenance, heavy equipment maintenance, air cargo, vehicle
washing, fuel transport, and waste accumulation. Chemicals used and handled in these areas include wastewater, oils,
hydraulic fluids, fuels, transformer fluids, and chlorinated solvents. The Air Force began operating these facilities in the
1940s and continue to the present day.
-------
An IROD for groundwater will allow interim remedial actions to begin quickly without
increased time necessary to negotiate final cleanup levels that would be required in a final ROD.
Actions taken under an IROD will use interim remedial goals, which are not enforceable
standards, but simply goals to use as tools for decision making. Travis AFB and the agencies will
determine the IROD/ROD strategy for the WABOU at a later time. Actions taken under different
RODs and IRODs need to be coordinated into an integrated approach. For example, treatment of
contaminated groundwater at Site SD033 may result in improvements to surface water and
sediment water quality in West Branch of Union Creek and therefore may affect remedial actions
in the ROD for soil, sediment, and surface water for SD033.
2.2.2.1 Removal Actions
Travis AFB has initiated expedited cleanups or removal actions in the NEWIOU to
address contaminated groundwater in portions of sites. Information obtained from these removal
actions has been used to help develop the interim remedial actions.
The Tower Area Removal Action (TARA) and Oil Spill Area (OSA), SS016 - The
TARA system, located within SS016, includes extraction wells, a carbon treatment system, and
discharge to irrigation lines or the storm sewer. As described in the "Engineering
Evaluation/Cost Analysis" (Radian, 1994), the Air Force designed and operated TARA to
remove high concentrations of volatile organic compounds (VOCs) in the groundwater and also
to protect workers during construction of a hydrant system near the tower. The system has
removed over 190 pounds of contaminants since the system began operation in 1995.
TARA is the only groundwater extraction system now operating at Travis AFB. The
Air Force expanded this extraction system under an Explanation of Significant Differences to the
"TARA EE/CA and Action Memo" (Radian, 1996d) to include the OSA and treats
approximately 90 gallons per minute. The treated water is used for landscape irrigation during
the dry season and will continue to be operated.
Travis AFB Groundwater IROD 39 as of 3 December 1997
-------
Jet Fuel Spill Area (JFSA), SS014 - The Air Force prepared an EE/CA and
environmental assessment (Earth Technology, 1994), which included a public comment period.
The action installed a treatment system in the southern part of the W1OU to remove fuel floating
on top of the groundwater. The system recovered more than 4,800 gallons of fuel which was then
recycled. This action is completed.
Outfall III Treatment System - The Air Force built a surface water treatment system
for VOCs at Outfall III (part of SD001) in 1995. The system was built as a part of a Time Critical
Removal Action (U.S. EPA, 1992) which used a liquid phase carbon system to remove TCE
from surface water collected via the storm sewer system from the upstream industrial area. The
system operated from June to September 1995 at a capacity of approximately 1,500 gallons per
minute. The system discharged treated water to Union Creek. The system was shut down because
TCE concentrations decreased after the TARA removal action was initiated. Operation of the
TARA system (SS016) may have reduced infiltration of contaminated groundwater into the
storm sewer system. Travis AFB does not anticipate the need to operate the system in the future
due to continued operation and expansion of the extraction system at OS A (SS016).
2.2.2.2 Treatabiliry and Pilot Studies
Monitoring Well (MW)-269 Area, SS030 - Actions at this site, located within SS030,
included a 10-month small scale treatment feasibility study conducted by Weston in 1993/94 and
a week-long 2-phase extraction test conducted by Radian in 1995. The objective of this
extraction test was to develop data to design a system to remediate VOC-contaminated soil and
groundwater. A Treatability Study is currently underway to investigate removal of off-base
contamination and control migration.
North/South Gas Station, ST018 - The Air Force, in cooperation with Lawrence
Livermore National Laboratories (LLNL), is undertaking a natural attenuation study to
Travis AFB Groundwater IROD 40 as of 3 December 1997
-------
investigate the rate and types of natural attenuation processes for contaminants at this site. This
site is now managed under the POCOS program.
SD036 - A natural attenuation study is being conducted by the Air Force Center for
Environmental Excellence (AFCEE) at SD036 (Facilities 872, 873, and 876). The study will
evaluate the feasibility of natural attenuation of chlorinated solvents using the technical protocol
jointly developed by AFCEE and U.S. EPA. The study is being conducted according to the
"Workplan For A Risk Based Remedial Action Assessment at Facilities 872, 873, and 876
(SD036)" (January 1997). The Air Force will use this natural attenuation study as a prototype for
other natural attenuation evaluations at Travis AFB.
2.2.3 CERCLA Activities for Groundwater at NEWIOU
2.2.3.1 Human Health Risk Assessments
The Air Force conducted human health risk assessments as an element of the RI process
for each of the three OUs. These assessments evaluated the risks to human health from the
constituents of concern. Each of the individual RIs include the assessments. Section 3.3 discusses
the results of these assessments.
2.2.3.2 Ecological Risk Assessments
The Air Force also completed ecological risk assessments (ERAs) for the OUs. Each of
the OU ERAs evaluates specific sites for completed exposure pathways, defines contaminants of
potential ecological concern (COPECs), defines assessment and measurement endpoints, defines
critical toxicity values (CTVs), and compares analytical sample data to the site specific CTVs.
Following the completion of the OU-specific ERAs, a document entitled "Final Comprehensive
Basewide Ecological Risk Assessment - Tier 2: Screening Assessment" (CH2M HILL, 1996),
designed to quantify the potential ecological risks to plants and animals on the Base using a
Travis AFB Groundwater IROD 41 as of 3 December 1997
-------
basewide perspective, was completed. This document provides further information on ecological
risk to help guide potential interim remedial actions. Section 3.3 of the Ground water IROD
presents more information on these ecological risk assessments.
2.2.3.3 RI/FS Activities
The Air Force completed remedial investigations at the three OUs (NOU, EIOU, and
WIOU). The final reports for the RJs are: Remedial Investigation, North Operable Unit, Travis
Air Force Base, California (Radian, 1995b); East Industrial Operable Unit Remedial
Investigation, Travis AFB (Weston, 1995a); and Remedial Investigation, West Industrial
Operable Unit, Travis Air Force Base, California (Radian, 1996b). Details regarding the RIs can
be found in these reports and are summarized in Section 3.0.
The findings of the three RIs indicate similar types of soil, groundwater, surface water,
and sediment contamination in the three OUs. The Air Force combined the NOU, EIOU, and
WIOU into one FS to be more cost effective. The FS for the NEWIOU is presented in the North,
East, and West Industrial Operable Unit Feasibility Study, (Radian, 1996a). The FS is
summarized in Section 4.0.
2.2.3.4 Community Participation
Travis AFB conducts a comprehensive effort to inform the public and involve the
community in the environmental decision-making process. Following are the highlights of the
community relations activities taken by Travis AFB to date:
Federal Facilities Agreement (FFA). The Air Force, U.S. EPA, California
Department of Health Services (now Department of Toxic Substances Control),
and SFBRWQCB have negotiated an interagency agreement, which includes
requirements for community relations activities based on provisions in federal
(and where applicable, state) statutes, regulations, and guidelines.
Travis AFB Groundwater IROD . 42 as of 3 December 1997
-------
Restoration Advisory Board (RAB). In 1994, Travis AFB established a RAB
comprised of representatives of the community and the regulatory agencies.
Through its quarterly meetings and its focus groups, the RAB has provided
valuable input about community concerns regarding the Restoration Program.
The Technical Document Review focus group has reviewed the draft of every
major report and provided comments. The Relative Risk focus group has
provided input on the project prioritization, and the Community Relations focus
group is working to reach out for new community members. The RAB replaced
the Technical Review Committee, which met periodically to review program
progress.
Administrative Record/Information Repository. The Air Force established an
Administrative Record of Information, used to support Air Force decision
making related to the IRP at Travis AFB. In addition, the Air Force established
a public information repository for the relevant portion of the Administrative
Record at the Vacaville Public Library.
Community Relations Plan (CRP). The Air Force implemented the first
Travis AFB CRP in 1991. The Air Force revised the CRP in 1995. The Travis
AFB Remedial Project Manager (RPM) is currently implementing the CRP.
Mailing List. A mailing list of all interested parties in the community is
maintained by Travis AFB and updated regularly. The mailing list currently
totals more than 1,300 names.
Fact Sheets and Newsletters. The Air Force has been publishing fact sheets
describing activities and milestones in the restoration program occasionally
since 1993. Since 1995 the Air Force has published and mailed quarterly
newsletters to everyone on the mailing list. The newsletters contain information
about public participation, issues of potential concern to the public, and program
updates. The RAB co-chairs also write columns in each newsletter.
Travis AFB has had a community relations program since 1990. Public review copies of the OU
RIs were made available:
• July 1995 (NOU);
October 1995 (EIOU); and
• February 1996 (WIOU).
Travis AFB Groundwater IROD 43 as of 3 December 1997
-------
The Air Force released the NEWIOU FS in September 1996. These documents are
available to the public at the Information Repository in Vacaville. The Air Force mailed the PP
to all parties on the Travis AFB mailing list, government officials, representatives of interested
co mm unity groups, and members of the media.
The Air Force held a 30-day public comment period for the NEWIOU Groundwater
Proposed Plan from 25 September 1996 through 24 October 1996. The Air Force held a public
meeting on the evening of 17 October 1996 from 7:00 p.m. to 9:00 p.m. At this meeting,
representatives from the Air Force, Cal-EPA/DTSC, the SFBRWQCB, and U.S. EPA answered
questions about the groundwater contamination off-base. Questions and comments from the
public and responses are included in Part III, the Responsiveness Summary.
2.2.3.5 Remedial Design/Remedial Action
The RD/RA will include the design and implementation of all actions specified in the
Groundwater IROD. The regulatory agencies will be involved in the approval and oversight of
the design and construction of the interim remedial actions. Experience gained through
implementation of the interim remedial actions will allow for technically and economically
feasible long-term remedial options in the final ROD for groundwater at Travis AFB.
The Air Force will submit the RD/RA schedule for implementing the IROD twenty-one
days after signing of the IROD in accordance with the FFA. The regulatory agencies will review
and approve the RD/RA schedule, as well as all reports and actions specified in the RD/RA
schedule. Section 5.4 presents the elements that will be included in the RD/RA schedule.
Travis AFB Groundwater IROD 44 as of 3 December 1997
-------
3.0 SUMMARY OF NEWIOU GROUNDWATER REMEDIAL INVESTIGATION
Section 3.1 summarizes the nature and extent of groundwater contamination in the
NEWIOU determined during the three separate remedial investigations for the North, West
Industrial, and East Industrial OUs. Section 3.2 presents a generalized conceptual model of
contamination at Travis AFB. Section 3.3 summarizes the risk evaluations performed as part of
the individual OU RIs. Section 3.4 discusses contaminants of concern, and the areas requiring
response actions. A summary statement is included in Section 3.5.
3.1 Nature and Extent of Contamination
Table 2-1 describes IRP sites with groundwater contamination within the NEWIOU.
The primary activities that generated waste at the base have been aircraft and vehicle fueling,
maintenance and repair. Waste streams generated at the base include used oils, contaminated
fuels, used hydraulic fluids, spent chlorinated and non-chlorinated solvents, and paint thinners.
Fuel handling, fire protection training, and grounds maintenance also have generated additional
waste streams. The Air Force has stopped the materials handling and disposal practices that
resulted in the contamination. Travis AFB now follows environmentally safe practices and
guidelines for the management and disposal of all hazardous materials and wastes.
In the past, Travis AFB disposed of some hazardous waste streams in landfills, to the
land surface, and by burning during fire training exercises. Starting in the 1960s, Travis AFB
collected these wastes for off-base recycling or disposal. Many of the facilities include wash
racks that are used for cleaning parts or aircraft. Travis AFB treated the aqueous waste streams
generated by these wash racks using oil/water separators, and discharged the streams to the storm
and sanitary sewers. Leakage from these separators or sewers may have contributed to the
groundwater contamination at the base. Travis AFB now enforces a no-discharge policy for any
industrial wastes to the storm drain system, has rerouted all such discharges to the sanitary sewer,
and complies with applicable district influent limitations.
Travis AFB Groundwater IROD 45 as of 3 December 1997
-------
Figure 3-1 shows the locations of the NEWIOU groundwater sites and the extent of
groundwater contamination.
The discussion of nature and extent focuses on groundwater contamination unless the
soil contamination at the site is relevant to the site description or to groundwater remediation.
Appendix A provides a summary of the pertinent environmentaJ information for each
groundwater site in the NEWIOU including a history of the site, information on the nature and
extent of contamination results of the FS evaluation, the site conditions that influence selection
of a remedy, and the selected interim action, including rationale.
3.1.1 North Operable Unit
The remedial investigation conducted at the NOU includes two landfills that were
recommended for further evaluation. Groundwater contamination was identified in three areas of
LF007 (Landfill 2) and in two areas of LF006 (Landfill 1). The sites and areas are shown in
Figure 3-2 and are:
• LF006 - Landfill 1, Area A and Area F;
LF007B - Landfill 2, Area B;
• LF007C - Landfill 2, Area C; and
LF007D - Landfill 2, Area D.
In general, LF006A, LF007B, and LF007C are similar in that each is part of two former
landfills with low concentrations (less than 50 micrograms per liter [ug/L] trichloroethene [TCE]
at LF006A and LF007C and less than 60 ug/L benzene at LF007B) of dissolved contaminants.
At LF007D, VOC concentrations are less than 50 ppb except a result of 282 ug/L for
chlorobenzene was detected. The groundwater contamination at LF006 is in two general areas.
Sampling results identified total petroleum hydrocarbons (TPH) contamination in the northern
Travis AFB Groundwater I ROD 46 as of 3 December 1997
-------
Unprotected
Stock Well
CD
O
5
73
O
O
O
780 1500 3000
4 !•
Scale In Feet
Groundwater (GW) Contaminant
Plume Migrating Off-Base
GW Contaminant Plume
within Base Boundary
Off-Base Private Water
Supply Wells
Travis AFB Boundary
OU Boundary
\s _j IRP Site Boundary
NB: Not all IRP Sites Include
groundwater contamination
April 1997
Figure 3-1. NEWIOU Groundwater Sites and
-------
o
3
33
O
o
cc
OFF BASE PORTION OF
GROUNDWATER CONTAMINATION
BUILDING 1365
HAZARDOUS WASTE
STORAGE FACILITY
LANDFILL 2
(LF007)
BUILDING 1360
MILITARY AFFILIATE
RADIO SYSTEM
LANDFILL 1
(LF006)
BUILDING 1367
LOADING DOCK
FORMER
DPDO
AREA
FORMER
SKEET
RANGE
FENCED BASE ROUNOWY
IRP SITE NUMBFK
SCAl E IN FEE I
IMAVI',/ MIHU.WV 'iAf VIH
Figure 3-2. NOU Sites and Areas with Groundwater Contamination
-------
part of LF006 (Area F) at concentrations up to 140 ug/L. In the southern part of LF006
(LF006A), groundwater contaminants include VOCs such as TCE and TPH.
At LF007B and LF007D, other contaminants of concern (COCs) in the groundwater
include semivolatile organic compounds (SVOCs), pesticides, and PCBs. Sampling results
detected dioxins in groundwater samples at concentrations above the U.S. EPA Preliminary
Remediation Goal (PRO) at one location in each area. The presence of PCBs and dioxins is
consistent with the disposal histories of these landfills; Landfill 2 received unspecified industrial
wastes. Sampling of downgradient wells in March 1996 indicate that the dioxins and PCBs have
not migrated (Radian, 1995b).
At LF007C, groundwater contaminated with dissolved chlorinated solvents extends
off-base no more than 200 feet based on cone penetrometer testing (CPT) data. Although the
local groundwater flow directions in this area of the base are towards the south and southwest,
local changes in the groundwater flow direction are caused by the irregular topography, near
surface bedrock and poor surface drainage. Such a local flow variation is responsible for
transporting the dissolved plume off-base to the north at LF007C.
Sampling results detected bis(2-ethylhexyl)phthalate in some groundwater samples
collected at LF007B and LF007D. This compound is associated with plastics.
3.1.2 East Industrial Operable Unit
The remedial investigation conducted at the EIOU includes IRP sites that were
recommended for further evaluation (Figure 3-3). These sites are:
• FT004 - Fire Training Area 3;
• FT005 - Fire Training Area 4;
Travis AFB Groundwater IROD 49 as of 3 December 1997
-------
o
I
73
O
O
C/l
O
E
o
-*»
UJ
5?
s
I
SDOJIXWTOO*
__ r Bifa,
i^fe-»# V ^'V'*'
OFF BASt PORTION OF'
GROUNDWATER CONTAMINATION
Figure 3-3. EIOU Sites with Groundwater Contamination
-------
• SS015 - Solvent Spill Area and Facilities 550 and 552;
SS016 -Oil Spill Area, Facilities 11, 13/14, 18,20, 42/1941, 139/144, and
selected sections of Storm Sewer Right of Way;
SS029 - MW-329 Area;
• SS030 - MW-269 Area;
• SD031 - Facility 1205; and
• ST032 -Areas MW-107 and MW-246.
FT005, SS015, and SS029 all have dissolved chlorinated VOC groundwater plumes
with COC concentrations less than 1,400 ug/L. COCs at SS029 are all VOCs, and COCs at
FT005 and SS015 include VOCs, SVOCs, and metals (nickel). While the activities conducted in
these areas were dissimilar in function, they all contributed to dissolved TCE (and related
breakdown products) contamination. At SS029 there is no clearly identified source area. Solvent
spills may be sources of contamination at SS015. The source of the contamination at FT005 is
probably the fire-training activities. Contaminated groundwater at FT005 extends approximately
500 feet south of the base boundary.
FT004, SS030, and SD031 have similar maximum concentrations of dissolved
chlorinated VOCs (TCE concentrations ranging from 2,400 ug/L to 8,100 ug/L. Other classes of
COCs at these sites include metals (nickel), plus one SVOC bis(2-ethylhexyl)phthalate at FT004.
The dissolved VOC plume from SS030 (the MW-269 area) has migrated beyond the base
boundaries approximately 1,400 feet. A Pilot Study is planned for SS030, with an estimated start
in the summer of 1997.
At SS016, groundwater samples from one well (MW-214) indicate the highest observed
concentration of dissolved TCE detected from a monitoring well sample at the NEWIOU
(32,000 fig/L). HydroPunch groundwater samples in the area detected TCE at a concentration
Travis AFB Groundwater IROD 51 as of 3 December 1997
-------
of 180,000 ug/L. This area is the focus of two early actions, the current OS A Removal Action
and the TARA that the Air Force has initiated in SS016 to address these areas of high TCE
concentrations in groundwater. Classes of COCs identified at SS016 include VOCs, one SVOC,
and one metal. SS016 includes the Storm Sewer Right-of-Way which is an area of potential
surface water/groundwater interaction that impacts Union Creek.
ST032 has high concentrations of dissolved fuel-related VOCs. Sampling from
monitoring wells at this site detected free-phase petroleum hydrocarbons. The highest benzene
groundwater concentration is 5,040 ug/L. TCE is also a COC at this site. Classes of COCs
identified at ST032 include VOCs and one SVOC. There is potential interaction between surface
water and groundwater at ST032 via the storm sewers that may lead to TCE and petroleum
migration to Union Creek.
In groundwater samples from FT004, FT005, SS015, SS016, and ST032, the Air Force
has occasionally detected bis(2-ethylhexyl)phthalate (a SVOC). Bis(2-ethylhexyl)phthalate is a
common laboratory contaminant and is associated with plasticizers. There is no history of plastic
disposal at this site; therefore, the detection of this chemical may not indicate groundwater
contamination, although it is considered a COC at these sites based on risks.
The Air Force has identified nickel as a COC in groundwater at Sites FT004, FT005,
SS015, SS016, SS030, and SD031. Treatment for metals may be needed to meet NPDES limits
(see Table 6-6). Sites with metals will have treatment processes for metals. The Air Force will
monitor actual levels of nickel and other metals during extraction/treatment system startup to
determine the need for metals treatment. The actual source of the nickel is unknown and
currently being investigated.
Travis AFB Groundwater IROD 52 as of 3 December 1997
-------
3.1.3 West Industrial Operable Unit
The remedial investigation conducted at the WIOU includes five sites that were
recommended for further evaluation (Figure 3-4). These sites are:
• SD033 - Storm Sewer System II/Facilities 810 and 1917, South Gate Area, and
West Branch of Union Creek;
• SD034-Facility 811;
• SS035-Facility 818/819;
SD036 - Facility 872/873/876; and
• SD037 - Sanitary Sewer System, Facilities 837, 838, 919, 977, and 981, Area G
Ramp, and Ragsdale/V Area.
SD033 and SD037 include the storm sewer system and the sanitary sewer system
within the WIOU and several facilities. Leaks from oil/water separators (OWSs) and other
industrial lines contributed to contamination in the groundwater. The Air Force has since
replaced or repaired the oil/water separators. In both of these areas, dissolved contamination in
the groundwater migrated along the permeable backfill around the pipes or into the storm sewer
directly through breaks or damaged areas. Wastewater from the oil/water separators and other
industrial lines has leaked out of damaged sewer sections into the groundwater.
Classes of COCs identified at SD033 and SD037 include VOCs and SVOCs. The
dissolved contaminants in these groundwater plumes include chlorinated solvents (and related
breakdown products), gasoline related compounds (TPH-G [VOCs]), and TPH-E SVOCs.
The storm sewer discharges into Union Creek, and the sanitary sewer discharges to the
Fairfield-Suisun Publicly Owned Treatment Works (POTW).
Travis AFB Groundwater IROD 53 as of 3 December 1997
-------
WEST BRANCH
UNION CREEK
SDOOl
TRAVIS BASE BOUNDARY
WIOU BOUNDARY
SITE BOUNDARY
SITE WITH GROUNDWATER
CONTAMINATION SHOWN
IN BOLDFACE
Figure 3-4. WIOU Sites with Groundwater Contamination
TRAVI36 WiOUGW 5-\C VR
Travis AFB Groundwater IROD
54
as of 3 December 1997
-------
Groundwater at SD034 is contaminated due to the presence of hydrocarbons in the
subsurface (primarily the solvent PD-680-a "Stoddard solvent" composed of 15% trimethyl
benzene and 85% n-nonane) and dissolved VOCs. Classes of COCs identified at SD034 include
VOCs and SVOCs. Floating product (PD-680) was found in a monitoring well located near the
OWS located at Facility 811. This OWS, which has been removed, was also connected to an
overflow pond located nearby. The OWS and the pond are the likely sources for the observed
contamination. The VOC contaminated groundwater plume may also be mixed with
contaminated groundwater at SD037.
Groundwater contamination at SS035 is characterized by low concentrations of
dissolved TCE (21 ug/L) and SVOCs such as TPH-extractable (TPH-E) (160 ug/L). Dissolved
contamination may have infiltrated into the aquifer due to a leaking OWS. TCE and TPH-E are
the only identified COCs at SS035.
Elevated concentrations of chlorinated solvents (cis-1.2-dichloroethene [DCE] up to
3,870 ug/L) have been detected in groundwater samples from SD036. Dissolved benzene, which
is thought to be associated with the wash rack or the OWS formerly located near Facility 872 has
also been detected at SD036. In addition to VOCs and petroleum compounds, one SVOC was
identified as a COC at SD036 (bis[2-ethylhexyl]phthalate). AFCEE is currently evaluating this
site for natural attenuation of chlorinated compounds such as TCE.
3.2 Conceptual Model of Contamination
The details of the conceptual models for each of the groundwater sites have been
discussed in the individual RIs. The site-specific summary sheets in Appendix A also contain
conceptual diagrams for each site.
Contaminants of concern can reach or leave the groundwater via many pathways. The
various mechanisms affecting contaminant concentrations throughout the NEWIOU include:
Travis AFB Groundwater IROD 55 as of 3 December 1997
-------
• Adsorption/desorption of organic chemicals to organic matter, or mineral
surfaces from free-phase, vapor phase, or dissolved phase contamination;
• Dissolution of organic compounds into infiltrating precipitation, vadose zone
pore water, and groundwater from adsorbed, free-phase, or vapor phase
contamination;
• Volatilization of VOCs from adsorbed, dissolved, or free-phase contamination
into the unsaturated zone;
• Vertical migration of dissolved VOCs and SVOCs into groundwater;
• Migration of free-phase VOCs and SVOCs through the vadose zone to the
groundwater;
• Diffusion of free-phase dense nonaqueous phase liquids (DNAPLs) into fine
grained silts and clays to form a secondary source;
• Migration or advection of dissolved phase contamination;
• Natural attenuation; and
• Migration of contaminated groundwater to surface water or storm sewers where
groundwater flows into surface waters.
Groundwater VOC concentrations greater than 3,000 \ig/L may indicate a potential for
residual or DNAPL (dense nonaqueous phase liquid; TCE is heavier than water; thus is termed a
DNAPL) contamination which can act as secondary sources of contamination. Free-phase
DNAPL can remain as a residual liquid within the pore spaces, or it can diffuse into low
permeability soils. This diffused DNAPL can also act like a residual source, even though the
resultant aqueous concentrations are lower than typically expected near the source zone (Cherry,
1996). These aqueous concentrations may be from 1,000 ng/L or greater. Because Travis AFB
aquifers are dominated by fine-grained silts and clays, DNAPL may have diffused into the finer
sediments. Maximum contaminant concentrations in samples from monitoring wells are
presented in Figure 3-5.
Travis AFB Groundwater IROD 56 as of 3 December 1997
-------
D
o
I
n
&
I
§
O
s?
8
8T
i
Figure 3-5.
Maximum Contaminant Concentration from Monitoring Wells
NEWIOU Groundwater Sites
All contaminants are TCE unless indicated. Sites with floating hydrocarbon are denoted by *.
15000 T-
chloro- cis-1,2-
benzene DCE
LF006 SS035 ST032' FT005 LF007 SS015
SD034* SD033 SS029
Site Number
SD036 SS030 FT004 SD037 SD031 SS016
-------
VOCs or SVOCs can be lost from the subsurface through volatilization and advection
of vapor phase contamination. In certain areas of the NEWIOU, dissolved groundwater
contaminants can enter the storm sewer systems through broken conduits and be discharged to
Union Creek. Dissolved VOCs migrating with the groundwater could reach Union Creek if the
groundwater table is above the elevation of the stream bed.
In Figure 3-6, areas of potential inflow of groundwater to storm sewers are shown if
there are any broken pipes or fractures in the storm sewer lines. The figure shows sections that
have the potential to receive inflow during the entire year or only when the water table is higher
during the winter months.
Natural attenuation of organic contamination leads to decreases in concentrations and
ultimately plume size. Biodegradation is the primary degradation pathway for dissolved organic
contamination at Travis AFB. Fuel hydrocarbons and non-chlorinated aliphatics are more
susceptible than chlorinated solvents to both aerobic and anaerobic biodegradation by
microorganisms. Aerobic biodegradation of fuel hydrocarbons uses dissolved oxygen as an
electron acceptor, and produces carbon dioxide and water. This can reduce dissolved oxygen
concentrations to less than 1 mg/L. Below 1 mg/L in concentration the oxygen levels are low
enough to permit anaerobic biodegradation to begin. Anaerobic degradation uses other
compounds as electron acceptors, and produces different byproducts such as methane and
sulfides (Wiedemeier et al, 1996). Natural attenuation is discussed as a remedial alternative in
Section 5.0.
Chlorinated solvents can biodegrade aerobically and anaerobically. Chlorinated
solvents are man-made, and these compounds undergo somewhat limited degradation due to their
microbial toxicity. These degradation mechanisms depend on complex chemical interactions
between the aquifer material, the dissolved VOCs, native bacteria, and the surrounding soil
vapor. Most often, these mechanisms degrade TCE or perchloroethene to 1,2-DCE or 1,1-DCE.
Travis AFD Groundwater IROD 58 as of 3 December 1997
-------
' CONIUIMAflON
iBASCO ON UARCn « *xO OCC "J» 0*1 w
MCA WITH POICNllAL IV1C*
-"-" 3MOt« Of «*C« i'inCO *MC»t ST
_..J ;;*(• o'PtHS i«x:ct>rwi c« >»CR
OtOlO i-'lS «"" S.i. •-fl'ui'.l on i.»f'cc «*rc«
'
figure >4.
Area* of Potential Grooadwalcr
Inflow bio Slonnwiur Scwcr SyiieM
Travi* Af B
Tn» Art Craw«in«r UWO
-------
These byproducts can then degrade to vinyl chloride, which can then be further reduced or
oxidized to benign compounds such as carbon dioxide and water (Wiedemeier et al, 1996).
Throughout the NEWIOU, it is common to find chlorinated solvent degradation products
dissolved in groundwater and soil vapor. This suggests that at least partial biodegradation is
occurring in the NEWIOU, and supports the feasibility of using natural attenuation to remediate
certain areas (Wiedemeier et al, 1996).
3.3 Risk Evaluation
Detailed information about the calculation of the human and ecological risks is in the
OU RIs. Table 3-1 summarizes the human and ecological risks posed by the dissolved chemicals
found in the groundwater at the NEWIOU IRP sites.
The objectives for the RIs and the health risk assessments conducted for the three OUs
that make up the NEWIOU were to define:
• OU-specific hydrogeology and a complete conceptual model;
• Approximate nature and extent of contamination;
• Risks to human health and the environment; and
• Sites, contaminants, and affected media to be considered in the FS.
Using contaminant concentrations from the field investigation, human health risk
values were calculated for a future residential scenario (adult reasonable maximum exposure
[RME]) for cancer risks, and child RME for noncancer risks and for industrial workers. The
future residential scenarios were the most conservative approach; although future use of
groundwater by residences was evaluated for the health risk assessment (HRA), future water is
likely to continue to be supplied basewide from sources outside Travis AFB. In addition, the
planned future use of most sites is industrial, not residential.
Travis AFB Groundwater IROD 60 as of 3 December 1997
-------
i
Table 3-1
I
a.
§
o
Summary of IRP Sites, Groundwater Contaminants, and Risks
Operable
Unit
NOU
IRP
Designation
LF006
LF007
LF007
Name/Description
Landfill 1
Landfill 2
AreaB
Landfill 2
AreaC
Medium
Groundwater
Groundwaler
Groundwater
Risk Criteria
Exceeded
Human
(Total Risk =
8x10"*)
Human
(Total Risk =
7.8 x 10"*)
Human
(Total Risk =
3.6 x 10"5)
Class of
Contaminants
VOCs
VOCs
SVOCs
Pesticidesb/PCBs
Oioxins
VOCs
Risk*
6.3 x 10"*
1.7 x 10"*
NA
3.9 xlO'3
1.9 x JO"3
HI=I.3
4. 1x10"*
7.0 xlO"4
1.3x10"*
1.6 xlO"5
5.6x10"*
3.5 x 10*
1.3x10"*
1.0 x IO'3
Contaminants of Concern
TCE
1,1-DCE
TPH
Benzene
1,4-DCB
Chlorobenzene
Bis(2-ethylhexyl)phthalate
PCBse
2,3,7,8-TCDDeq
TCE
Vinyl Chloride
1,1-DCE
1,2-DCA
1 ,2-Dichloropropanc
Maximum
Reported
Concentration
20 ug/L
0.64 ug/L
330 ug/L
59.3 ug/L
30.8 ug/L
161 ug/L
14.3 ug/L
13.5 ug/L
(PCB-1248)
0.55 pg/L
49.1 ug/L
0.1 98 ug/L
0.297 ug/L
0.3 14 ug/L
3.38 ug/L
Maiimum
Contaminant
Levels'
5 ug/L
6 ug/L
TBD'
lug/L
5 ug/L
70ng/L
4fig/L
0.50 ug/L
0.03 pg/L
5 ug/L
0.5ng/L
6 ug/L
0.5 ug/L
S»gfL
R
o
•-•>
Ul
5?
s
I
-------
Table 3-1
(Continued)
Openble
Unit
NOU
EIOU
IRP
Designation
LF007
FT004
Name/Description
Landfill 2
AieaD
FTA-3
Medium
Groundwaler
Groundwaler
Risk Criteria
Eiceeded
Human
(Total Risk -
5.4 x 10^)
Human
Class of
Contaminants
VOCs
Dioxins
Pesticides*/PCBs
SVOCs
VOCs
SVOCs
Metal
Risk*
l.4xlO"J
2.9 x 10^
2.5 x 10'5
1.1x10"*
HI =15.5
2.4 x ID'1
2.2 x Id"1
8.2 x IO"6
1. 69x10°
Contaminants of Concern
Benzene
Vinyl Chloride
1,4-DCB
1,1 -DCE
Chlorobenzcne
2,3,7,8-TCDDeq
PCBse
Bis(2-eihylhexyl)phthaJate
TCE
cis-l,2-DCE
1,2-DCA
Chloroform*
Dichlorobromomethane*
1.1 -DCE*
Vinyl Chloride*
1,4-DCB*
Bis(2-elhylhexyl)phlhalale
Nickel
Maximum
Reported
Concentration
25.8 Mg/L
1.78 Mg/L
43.8 Mg/L
0.96 Mg/L
282 Mg/L
!6.99pg/L
14.1 ugA.
(PCB-1242)
124 Mg/L
5.200 Mg/L
14.7 Mg/L
5.12 Mg/L
1.81 Mg/L
3.1 Mg/L
1.28 Mg/L
6.1 Mg/L
3.8 Mg/L
5.49 ug/L
2,540 mg/L
Maximum
Contaminant
Levels'
lug/L
0.5 Mg/L
SMB/L
6 Mg/L
70 Mg/L
0.03 pg/L
0.50 Mg/L
4 Mg/L
5 Mg/L
6 Mg/L
0.5 Mg/L
100 Mg/L
100 Mg/L
6 Mg/L
0.5 Mg/L
5 Mg/L
4 Mg/L
O.I mg/L
o
o
o\
NJ
s?
s
S"
-------
Table 3-1
(Continued)
Operable
Unit
EIOU
IRP
Designation
FT005
SS015
Name/Description
FTA-4
SSA (Fac. 552)
Medium
Groundwaler
Groundwater
Risk Criteria
Exceeded
Human
Human
Clajj of
.Contaminants
VOCs
SVOCs
Metal
VOCs
SVOCs
Metal
Risk'
1. 12x10"*
7.22 x 10"*
Contaminants of Concern
TCE
1,2-DCA
cis-I,2-DCE
Chloroform*
Dichlorobromomethane*
Bis(2-e(hylhexyl)phthalate
Nickel
TCE
cis-l,2-DCE
Vinyl Chloride
1,4-DCB*
1,2-DCA*
PCE
Bis(2-e(hylhexyl)phthalate
Nickel
Maximum
Reported
Concentration
120 Mg/L
14.2 Mg/L
19 Mg/L
10 Mg/L
1.8 Mg/L
35.9 Mg/L
370 mg/L
25 Mg/L
370pg/L
48 ug/L
3.8^g/L
0.39 pt/L
\2pgfL
6.68 ug/L
l,500mg/L
Maximum
Contaminant
Levels'
5 Mg/L
0.5Mg/L
6 ug/L
100 Mg/L
100 ug/L
4 ug/L
O.I mg/L
SugA-
6 ug/L
0.5 ng/L
5 Mg/L
0.5 Mg/L
5 Mg/L
4 Mg/L
0. 1 mg/L
o.
I
I
O\
K
o
-^
u>
s?
s
-------
Table 3-1
(Continued)
Operable
Unit
EIOU
IRP
Designation
SSOI6
; Name/Description
OSA, Fac. II,
Fac. 13/14, Fac. 20,
Fac. 42/1 941,
Fac. 139/144
Medium
Groundwater
Risk Criteria
Exceeded
Human
V"' Class of
Contaminants
VOCs
SVOCs
Metal
': Risk1 ":V.
l.llxlO'2
Contaminants of Concern
TCE
cis-l,2-DCE
Vinyl Chloride
Benzene
Chloroform*
1,4-DCB*
Dichlorobromomclhane*
1,2-DCA
1,1-DCE
PCE
Bis(2-ethylhcxyl)ph(halate
Nickel
Maximum
Reported
Concentration
32,000 Mg/Ld
4,600 ug/L
56 Mg/L
6.4 ug/L
4.7 Mg/L
8.6 Mg/L
0.9fig/L
3.97 Mg/L
5.4ng/L
220 ugA.
67.3 ng/L
460mg/L
Maximum
Contaminant
Levels'
5ug/L
6>ig/L
O.Sng/L
1 Mg/L
lOOjig/L
5 Mg/L
100 Mg/L
0.5 (ig/L
6 Mg/L
5 Mg/L
4 Mg/L
O.I mg/L
O
o
K
o
-------
Table 3-1
(Continued)
Operable
Unit
EIOU
IRP
Designation
SS029
SS030
SD031
Name/Description
MW-329Area
MW-269Area
Fac. 1205
Medium
Groundwater
Groundwater
Groundwater
Risk Criteria
Exceeded
Human
Human
Human
Class of
Contaminants
VOCs
VOCs
Metal
VOCs
Metal
Risk*
4.22 x W4
7.6 x 10"4
5.24 x IO'2
Contaminants of Concern
TCE
1,2-DCA
cis-l,2-DCE
Benzene*
Chloroform*
1.1 -DCE*
Vinyl Chloride*
TCE
Chloroform*
Dichlorobromomelhane*
1,2-DCA*
Nickel
TCE
Benzene
1,1 -DCE
cis-l,2-DCE
Carbon Telrachloride
Chloroform
1,2-DCA
Vinyl Chloride
Nickel
Matimum
Reported
Concentration
1,300 Mg/L
H3Mg/L
80 Mg/L
0.55 Mg/L
0.61 |ig/L
0.57 Mg/L
0.22 Mg/L
2,400 Mg/L
1.2 Mg/L
0.53 ug/L
0.34 ug/L
903 mg/L
8, 100 ug/L
6.75 ng/L
7,300 ug/L
3,600 ug/L
II Mg/L
4.34 ug/L
0.41 ug/L
0.22 fig/L
2.050 mg/L
Maximum
Contaminant
Level]'
5 Mg/L
0.5 Mg/L
6 Mg/L
lMg/L
100 ug/L
6 Mg/L
0.5 Mg/L
5 Mg/L
100 Mg/L
100 Mg/L
0.5 Mg/L
O.I mg/L
5 Mg/L
lug/L
6 Mg/L
6 Mg/L
0.5 Mg/L
100 Mg/L
0.5 Mg/L
0.5 Mg/L
O.I mg/l.
o
o
-------
Table 3-1
a
(Continued)
Openble
Unit
EIOU
WIOU
1RP
Designation
ST032
SD033
Name/Description
MW- 1 07 Area and
MW-246 Area
Storm Sewer System
II (former Storm
Sewer System B)
(includes Facilities
810, 1917, and
South Gate Area,
and the West Branch
of Union Creek
Medium
Groundwater
Groundwater
Risk Criteria
Exceeded
Human
Human
(Total Risk =
5.6 x I0~5)
Cli« of
Contaminants
VOCs
SVOCs
VOCs
SVOCs
Risk*
1.5 xlO'2
3.6 xlO"3
1.7x10"*
Exceeds MCL
Exceeds MCL
NA
NA
Contaminants of Concern
Benzene
TCE
I.I-DCE*
Xylenes*
Bis(2-ethylhexyl)phlhalate*
TCE
1,1 -DCE
1,2-DCA
cis-l,2-DCE
TPH-gasoline
TPH-E
Maximum
Reported
Concentration
5,040 ug/L
64 ug/L
0.36 ug/L
6.702 ug/L
153 ug/L
94lpg/L
0.420 ug/L
1.36 ug/L
199 ug/L
1.000 ug/L
1.420 ug/L
Maximum
Contaminant
Levels'
lug/L
5pg/L
6 ug/L
l,750Mg/L
4 ug/L
5 ug/L
6Mg^
0.5 ugA.
6pg/L
TBD'
TBD*
§
o
0\
s?
n
o
-------
Table 3-1
(Continued)
Operable
Unit
WIOU
IRP
Designation
SD034
SS035
Name/Description
Facility 811
Facilities 818
and 819
Medium
Groundwater
Groundwater
Risk Criteria
Exceeded
Human
(Total Risk =
6.2 x IO"4)
NA
Class of
Contaminants
VOCs
SVOCs
VOCs
SVOCs
Risk*
NA
3.0 xlO'5
3.1 x IO'5
1.2x10"*
Exceeds MCL
Exceeds MCL
1.2 xlO'5
NA
NA
3.3x10"*
Exceeds MCL
NA
Contaminants of Concern
LNAPL (PD-680)
TCE
Vinyl Chloride
I.I-DCE
Benzene
cis-l.2-DCE
PCE
TPH-gasoline
TPH-E
Bis(2-ethylhexyl)phthalate
TCE
TPH-E
Maximum
Reported
Concentration
- 1 foot thick
740Mg/L
2.38 jig/L
0.317»ig/L
6.8ng/L
496 ng/L
88(ig/L
1 0,600,000 jig/L
1 3,000,000 fig/L
6.390 ng/L
21 Mg^
l60Mg/L
Maximum
Contaminant
Levels'
NA
5jig/L
0.5|ig/L
6ng/L
lMg/L
6>ig/L
5Mg^
TBD'
TBD'
4»ig/L
5ng/L
TBD'
.
V
5
53
o
o
S?
s
I
-------
Table 3-1
(Continued)
03
§
§
D
Operable
Unit
WIOU
IRP
Designation
S0036
Name/Description
Facilities 872. 873,
and 876
Medium
Groundwater
Risk Criteria
Exceeded
Human
(Total Risk =
1.3x10"')
Class of
Contaminants
VOCs
Risk*
2.lxlO'J
2.4 xlO"5
2.2 xlO'5
HI - 6.2
Exceeds MCL
1.2x10"*
1.0 x 10"*
l.6x 10"*
NA
NA
Contaminants of Concern
Vinyl Chloride
TCE
I.I-DCE
cis-l,2-DCE
1,2-DCA
Benzene
Bromodichloromethane
PCE
TPH-gasoline
TPH-E
Maximum
Reported
Concentration
198 Mg/L
308 Mg/L
3.71 Mg/L
3.870 Mg/L
1.36 Mg/L
3.87 Mg/L
2.26 Mg/L
382 pg/L
4.380 Mg/L
480 Mg/L
Maiimum
Contaminant
Level*'
0.5 Mg/L
5 Mg/L
6 Mg/L
6 Mg/L
0.5 Mg/L
1 MB/L
O.I8fJg/L
5MgA,
TOD'
TDD'
00
I
i
-------
Table 3-1
(Continued)
Operable
Unit
WIOU
IRP
Designation
SD037
Name/Description
Sanitary Sewer
(includes Facilities
837,838,981.919.
the Area G Ramp,
and Ragsdale/V
Area)
Facility 977
(Sanitary Scwcr)
(SD037)
Medium
Groundwaler
GrounJwaier
Risk Criteria
Exceeded
Human
(Total Risk -
1.6x10^)
NA
Class of
Contaminants
VOCs
SVOCs
VOCs
SVOCs
Risk*
l.lx 10"*
Exceeds MCL
1.9 xlO'7
Exceeds MCL
Exceeds MCL
l.3x 10'*
4.6x 10"3
5.4 xlO'5
6.0 x IO'5
Exceeds MCL
NA
l.4x 10*
Exceeds MCL
NA
NA
Exceeds MCL
NA
Contaminants of Concern
I.I-DCE
1,2-DCA
Benzene
Bromodichloromethane
Carbon Tctrachloride
Chloromethane
PCE
TCE
Vinyl Chloride
cis-l,2-DCE
TPH-gasoline
Bis(2-elhylhexyl)phthalate
Naphthalene
TPH-E
TPH-gasolinc
TCE
TPII-E
Maximum
Reported
Concentration
0.598 Mg/L
0.597 Mg/L
1. 93 Mg/L
0.69 Mg/L
60.7 Mg/L
1.03 Mg/L
407 Mg/L
6.990 Mg/L
60.2 Mg/L
340 jig/L
4. 160 Mg/L
139 Mg/L
115 Mg/L
34,000 Mg/L
61 Mg/L
12.2 Mg/L
2,660,000 Mg/1.
Maximum
Contaminant
Levels'
6 ug/L
0.5 Mg/L
lug/L
O.I8Mg/L
0.5 Mg/L
1.50 Mg/L
5 Mg/L
5 Mg/L
0.5 Mg/L
6 Mg/L
TBDe
4 Mg/L
23 ug/L
TOD*
i ni)c
5 ng/L
(HI)'
o
o
D
-------
Table 3-1
(Continued)
Operable
Unit
WIOU
IRP
Designation
SD037
Name/Description
Facility 981
(Sanitary Sewer)
(SD037)
Area G Ramp
(Sanitary Sewer)
(SD037)
Medium
Groundwatcr
Groundwater
Risk Criteria
Exceeded
NA
NA
Class of
Contaminants
VOCs
SVOCs
VOCs
SVOCs
Risk*
Exceeds MCL
Exceeds MCL
NA
NA
Exceeds MCL
Exceeds MCL
Exceeds MCL
NA
NA
Contaminants of Concern
Benzene
TCE
TPH-gasoline
TPH-E
Benzene
PCE
TCE
cis-l,2-DCE
TPH-E
Maximum
Reported
Concentration
14 Mg/L
2.65 Mg/L
790 Mg/L
530 Mg/L
2.3 ng/L
17 jig/L
6.7 Mg/L
1.32 Mg/L
4, 100 Mg/L
Maximum
Contaminant
Levels'
lMg/L
6 Mg/L
TBD'
TBD'
lMg/L
5 Mg/L
5 Mg/L
6 Mg/L
TBD'
O
' = Risk is for each COC contributing lo lotal risk. Noncarcinogenic human health risks are reported as hazard indexes (HI); an HI greater than I suggests there may be i potential for adverse effects. Ecological risks
are reported as maximum hazard quotients (HQ); an IIQ greater than I suggests there may be a potential for adverse effects.
» Pesticides were deleted from consideration in the FS for the NOD. See FS Report for discussion.
c - PCBs include Arochtors 1242 and 1248.
• Recent testing has documented higher concentrations of TCE, up to a maximum of approximately 180,000 ppb. However, these results were derived from Cone Penelromclcr Testing (CPT) data and should not be
directly compared lo monitoring well data.
' - Maximum contaminant levels (MCLs) presented are California Department of Health Services Primary MCLs, except where noted. U.S. EPA PRGs are used for chloromethane and lotal petroleum hydrocarbons
have no limits in groundwater, and thus are TBD.
• This table contains revisions from (he numbers in Table F.S-2 from the EIOU RJ (Weston, 1995). Revisions are based on recalculated risks (April, 1996). Contaminants of concern that have been added lo mis table are
noted by an asterisk ('). In addition, PCB (Aroclor-1260) was removed as a human health risk (I I April 1996) based on an industrial exposure scenario rather than a residential scenario.
5?
8
Note: All metals concentrations are dissolved (filtered samples).
DCA
DCI)
DCE
III
110
' Uichloroethane
•• Uichlorobcnzene
> Uichloroclhenc
• Hazard Index
- Hazard Quotient
Mg/L - Micrograms per Liter
NA = No maximum contaminant level available for this chemical or risks not calculated
OSA = Oil Spill Area
I'CO = Pol)chlorinated Biphenyls
PCE = Tetrachloroelhene
pg/g « Picugrams per Gram
SVOCs ° Semivolalile Organic Compounds
TBD "Tobe determined
TCDD => 2,3,7,8-letrachlorodibenw-p-dio.xin
TCE " Trichloroelhene
TPII-E = Total Petroleum I lydrocarbons - Exlraclable
TPH -Total Petroleum I lydrocarbons
VOCs ° Volatile Organic Compounds
-------
The Air Force also completed ecological risk assessments (ERAs) for the OUs. Each of
the OU ERAs evaluates specific sites for completed exposure pathways, defines COPECs,
defines assessment and measurement endpoints, defines CTVs and compares analytical sample
data to the site specific CTVs. Depending on the risk analysis, routes of exposure and selected
indicator species, CTVs may be expressed as doses or as environmental concentrations. The
comparison of modeled doses or analytical concentrations to CTVs results in a hazard quotient
(HQ). HQs exceeding 1 indicate a potential for adverse ecological effects. Specific OU ERAs
also included additional analyses to assess ecological impact of contaminants. These included:
gross pathology of organisms; site specific bioassays; biomass analysis; and biological sampling
and analysis. These ERA analyses, other than the HQ analysis, may not be chemical end-point
specific, but they assume all chemical concentrations identified at a site are responsible for the
observed toxic endpoint (e.g., skin lesions on fish at the site).
Following the completion of the OU-specific ERAs, a document entitled "Final
Comprehensive Basewide Ecological Risk Assessment - Tier 2: Screening Assessment" (CH2M
HILL, 1996), designed to quantify the potential ecological risks to plants and animals on the
Base using a basewide perspective, was completed. This document provides further information
on ecological risk to help guide potential interim remedial actions.
The Tier 2 report presents general surface water and sediment goals based on federal
standards. A supplemental approach was required to establish ecological interim remediation
goals (IRGs) in the FS, specifically for soil at the NEWIOU sites. The Air Force estimated these
IRGs by back-calculating media-specific concentrations to yield an HQ = 1, using the algorithms
developed in the previous ERAs. The methodology involved selecting a "most sensitive
receptor" for each site or habitat type, again based on the ERAs, to represent all ecological
receptors. The Air Force and regulatory agencies selected these receptors to represent species that
are likely to utilize the site, have a high level of contact with the contaminated media, and have
available toxicity data. Exposure pathways, bioaccumulation/bioconcentration parameters,
uncertainty factors, and toxicity data were all reviewed and factored into the analysis. The Air
Travis AFB Ground water IROD 71 as of 3 December 1997
-------
Force then back-calculated the individual IRGs for each COC at each site, so that the IRG
concentration would result in a theoretical HQ = 1.
Specific details of the HRAs for the three OUs that compose the NEWIOU are provided
in the OU RIs and the NEWIOU FS.
The site-specific figures in Appendix A summarize primary groundwater contaminants
that were evaluated in the FS. The summary figures for all sites include estimated areas of
contamination; a complete description of the nature and extent of contamination is contained in
the specific RIs. Compounds that do not drive risk or do not exceed regulatory standards are not
shown on these figures.
3.4 Contaminants of Concern
Following the RI field activities, the Air Force compiled the data for each site and
evaluated the data in each OU RI for the presence of contaminants and their potential effects on
human health and the environment. The Air Force and regulatory agencies identified COCs
based on potential human health risks, ecological risks, and regulatory limits. While each OU RI
considered site-specific factors, the general criteria for the identification of groundwater COCs
was as follows:
1. The contaminant drove a human health risk exceeding 1 x 10"6;
2. The contaminant had an HI exceeding 1.0; or
3. The maximum concentration of the contaminant exceeded the maximum
contaminant level (MCL) (or PRGs for dioxin).
A detailed description of COC development is included in each of the OU RIs. COCs
are listed in Table 3-1.
Travis AFB Groundwater IROD 72 as of 3 December 1997
-------
3.5 Summary
Releases of VOCs, as well as SVOCs, dioxins, and metals as a result of historic Base
activities have contaminated the groundwater at the NEWIOU at Travis AFB. Most of the
releases affecting groundwater at the NEWIOU involve TCE. Actual or threatened releases of
hazardous substances from these sites, if not addressed by implementing the response actions
selected in the Groundwater IROD, may present a current or potential threat to public health, and
welfare, or to the environment.
As a result of the NOU, WIOU, and EIOU RIs, twenty sites were evaluated in the
NEWIOU FS, fifteen of which have groundwater contamination. Five of the twenty sites
(SD001, FT002, FT003, OT010, and WP017) do not have groundwater contamination. The
fifteen groundwater sites are shown in Table 3-2. The Air Force and regulatory agencies delisted
four sites and moved them to the Petroleum-Only Contaminated Sites (POCOS) program. These
include SS014, ST018, SS027, and SS028. One site (OT011) was designated as no further action.
Travis AFB Groundwater IROD 73 as of 3 December 1997
-------
Table 3-2
Summary of NEWIOU Groundwater Sites
Carried Forward to the NEWIOU FS
ysf!-oia /,
EIOU
NOU
WIOU
IRP Designation
FT004
FT005
SS015
SS016
SS029
SS030
SD031
ST032
LF006
LF007
SD033
SD034
SS035
SD036
SD037
*-' "",\, ' '"'*>'" -; -, '--, ' Name; / (,'-' "- ' '
Fire Training Area (FTA>3
FTA-4
Solvent Spill Area (SSA) and Facilities 550 and 552
Oil Spill Area (OSA) Facilities 11,13/14, 20, 42/1941, 139/144,
and Storm Sewer Right of Way
Monitoring Well (MW)-329 Area
MW-269 Area
Facility 1205
MW-246/MW- 1 07 Areas
Landfill 1
Landfill 2
Facilities 810 and 1917, Storm Sewer II, South Gate Area,
and West Branch of Union Creek
Facility 811
Facility 8 18/8 19
Facility 872/873/876
Sanitary Sewer System, Facilities 837/838, 919, 977, 981,
Ragsdale/V Area, and Area G Ramp
Note: Soil, sediment, and surface water contamination at these and other NEWIOU soil sites will be addressed in a separate ROD. For potential
migration of ground water to surface water, see Figure 3-6.
Travis AFB Groundwater IROD
74
as of 3 December 1997
-------
4.0 SUMMARY OF NEWIOU GROUNDWATER FEASIBILITY STUDY
The Air Force performed a Feasibility Study (FS) for the NEWIOU and the results are
summarized in the FS Report dated September 1996. The FS consisted of the following
activities:
• Develop Remedial Action Objectives;
• Combine cleanup technologies into remedial alternatives;
• Perform an Initial Screening of Alternatives;
• Evaluate each alternative against specific criteria;
• Perform a Detailed Analysis of Alternatives; and
• Rank each alternative for total score and cost/benefit.
This section describes each of the nine alternatives evaluated in the FS and how the Air Force
combined Alternatives 3 through 9 into one alternative (Alternative 3) for this IROD. The Air
Force and regulatory agencies developed Remedial Action Objectives (RAOs) in the FS to
address contamination cleanup. As described in Section 3.3, the Air Force and regulatory
agencies developed Interim Remediation Goals (IRGs) in the RI. The IRGs are risk based
cleanup goals which are similar to cleanup levels but they are not enforceable. The Air Force
used both IRGs and RAOs in the FS to evaluate the alternatives against specific criteria as
described in Section 4.3.
4.1 Alternative Description
The Air Force and regulatory agencies first developed alternatives in the FS by
performing an Initial Screening of Alternatives (ISA) process. This screening considered the
environmental conditions at each site, the RAOs, and the IRGs to screen all potential remedial
Travis AFB Groundwater IROD 75 as of 3 December 1997
-------
technologies for applicability for remediation of contaminated groundwater. The screening
process evaluated the effectiveness, implementability, and cost of each technology. The Air
Force combined the technologies that passed the screening into a set of alternatives that could
address each of the groundwater sites. The Air Force and regulatory agencies then subjected
these alternatives to the second part of the FS process, the Detailed Analysis of Alternatives
(DAA), which is summarized in Section 4.3.
The alternatives evaluated in the FS for groundwater were:
Alternative # 1: No Action
Alternative #2: Institutional Actions: Access Restrictions, Monitoring,
Natural Attenuation
Alternative #3: Horizontal Well Extraction, Air Stripper/Catalytic Oxidation,
Ion Exchange, Activated Carbon, Discharge to Irrigation
and/or Storm Drain
Alternative #4:
Alternative #5:
Alternative #6:
Alternative #7:
Alternative #8:
Alternative #9:
Horizontal Well Extraction, Air Stripper/Catalytic Oxidation,
Activated Carbon, Discharge to Irrigation and/or Storm Drain
Horizontal Well Extraction, Ultraviolet Radiation and
Oxidation (UV-OX), Ion Exchange, Activated Carbon,
Discharge to Irrigation and/or Storm Drain
Horizontal Well Extraction, UV-OX, Activated Carbon,
Discharge to Irrigation and/or Storm Drain
Horizontal Well Extraction, Ion Exchange, Activated Carbon,
Discharge to Irrigation and/or Storm Drain
Horizontal Well Extraction, Activated Carbon, Discharge to
Irrigation and/or Storm Drain
Vertical Well Extraction, Bioslurping, Recovered Product
Recycling, Off Gas Catalytic Oxidation
Travis AFB Groundwater 1ROD
76
as of 3 December 1997
-------
These alternatives are summarized in the following sections. For the PP and IROD, the Air Force
consolidated Alternatives #3 through #9 into a new Alternative 3, since the FS found that these
active treatment alternatives had similar costs and effectiveness ratings.
4.1.1 No Action
This alternative (Alternative 1 in the FS) leaves the site as it is. No action is used as a
baseline option for all sites. Under this alternative, the base would undertake no activity toward
cleanup or risk mitigation. CERCLA guidance requires that the No Action alternative always be
considered as a baseline alternative in an FS.
4.1.2 Natural Attenuation/Monitoring (Institutional Actions)
This alternative (Alternative 2 in the FS, where it was called "Institutional Actions")
uses institutional controls to restrict access to groundwater and allows contaminant
concentrations to naturally attenuate. This option includes monitoring to evaluate the effect of
natural attenuation on contaminants in groundwater. The Air Force would perform monitoring to
confirm the stability of impacted groundwater and to provide an early warning if contaminants
threatened receptors, such as agricultural wells or ecological receptors. Monitoring would also
track the decline in concentrations resulting from natural attenuation processes.
4.1.3 Extraction, Treatment, and Discharge
Alternatives 3 through 9 in the FS all used extraction with different types of treatment;
therefore, the Air Force subsequently consolidated them into Alternative 3 for the PP and the
Groundwater IROD. Alternative 3 addresses contaminated plumes by extracting contaminated
groundwater and then treating to comply with regulations for discharge of water.
Travis AFB Groundwater IROD 77 as of 3 December 1997
-------
The Air Force evaluated five groundwater treatment options in the FS. The five
treatment options were: air stripping; catalytic oxidation (catox); UV-OX; ion exchange; and
activated carbon. The Air Force combined these five treatment options into 7 different treatment
trains as described in the NEWIOU FS. Extraction, treatment, and discharge processes are
summarized below. A more detailed description of these processes is provided in Section 5.2.2 of
the Groundwater IROD.
4.1.3.1 Extraction
Extraction processes include both horizontal and vertical extraction wells. Bioslurping,
two-phase, dual phase or soil vapor extraction systems to remove soil gas, floating petroleum
product and/or groundwater are methods to enhance extraction and were also included.
4.1.3.2 Treatment
The five general or representative treatment processes covered in the NEWIOU FS are
summarized below.
Air Stripping - Air stripping utilizes the volatility of many common organic
contaminants to remove them from the contaminated water and transfer them to the gaseous
phase. Contaminated water is introduced to the top of the tower while air is blown upwards
through the tower. The agitation provided by the air and plates or synthetic media within the
column break up the water into small droplets, providing a large water surface-to-air interface for
organics to volatilize into the air phase. Treated water exits the bottom of the tower while air
carrying the organic contaminants exits the top of the tower.
Catalytic Oxidation - Catalytic oxidation processes use a catalyst, which is a material
that accelerates a chemical reaction but is not itself consumed in the reaction, to oxidize
Travis AFB Groundwater IROD 78 as of 3 December 1997
-------
contaminants. This technology would be used to treat contaminants in process offgas streams,
e.g., from air stripping processes.
Activated Carbon - Activated carbon can be used to treat groundwater for removal of
VOCs; the carbon is replaced or regenerated once the adsorbent is saturated. Activated carbon
can also be used to treat VOCs in the vapor phase effluent from a treatment process.
Ion Exchange - Ion exchange systems are used for metals removal. Ion exchange
systems use polymeric resins (or inorganic media) to sorb specific suites of metals from the
water. Metal hydroxide precipitation is used following a pH adjustment step.
Ultraviolet Radiation and Oxidation (UV-OX) - UV-OX is a liquid phase process
and requires chemical reagents, such as hydrogen peroxide, promoted with UV light to destroy
VOCs. This process option differs from an air stripper because there is no generation (and
required subsequent treatment) of an offgas stream.
4.1.3.3 Discharge
The FS assumed treated groundwater would be discharged to Travis AFB's non-potable
water irrigation system or directly discharged on-base to surface water meeting NPDES limits,
such as Union Creek and the storm drain system. These options are performed for the ongoing
groundwater removal actions.
4.2 Summary of Comparative Analysis of Alternatives
This section summarizes how the Air Force and regulatory agencies evaluated the three
alternatives (Alternative 1 - No Action, Alternative 2 - Natural Attenuation/Monitoring, and
Alternative 3 - Extraction, Treatment, and Discharge) against EPA's nine criteria in the FS. The
Air Force and regulatory agencies divided these criteria into three classes: threshold criteria,
Travis AFB Groundwater IROD 79 as of 3 December 1997
-------
balancing criteria, and modifying criteria. The following sections discuss each of these types of
criteria, and how the alternatives were compared. Figure 4-1 defines the evaluation criteria, while
Table 4-1 compares the alternatives to the threshold and balancing criteria.
4.2.1 Threshold Criteria
4.2.1.1 Overall Protection of Human Health and the Environment
Alternative 3 (Extraction, Treatment, and Discharge) would provide the greatest
protection of human health and the environment since the contaminants would be removed by
extraction. Alternative 2 (Natural Attenuation/Monitoring) would be protective of human health
and the environment if natural attenuation is taking place and there is no pathway to receptors
such as using groundwater for drinking water. Alternative 1 (No Action) would not be protective
because people and the environment could be exposed, or potentially exposed, to groundwater.
Without monitoring, the Air Force and regulatory agencies could not assess natural attenuation of
the groundwater and the subsequent rate of risk reduction.
4.2.1.2 Compliance with ARARs
The Air Force would achieve compliance with ARARs for Alternative 3. Although the
Air Force and regulatory agencies have not established final cleanup levels for groundwater at
Travis AFB, the interim actions using Alternative 3 will reduce contamination and potential risk.
In addition, the Air Force and regulatory agencies will use the data obtained to allow for
selection of final cleanup levels and technically and economically feasible long-term remedial
actions.
If natural attenuation is taking place and the plume is stable or decreasing in size at the
sites where the Air Force implements this alternative, then Alternative 2 may meet ARARs.
Travis AFB Groundwater IROD 80 as of 3 December 1997
-------
THRESHOLD CRITERIA
1 Overall Protection of Human Health and the Environment
Addresses whether a remedy provides adequate protection of
human health and the environment and describes how risks are
eliminated, reduced, or controlled through treatment, engineering
controls, or institutional controls.
2 Compliance with Applicable or Relevant and Appropriate
Requirements (ARAIte)
Addresses whether a remedy wil meet all ARARs or federal and
state environmental statutes and/or provide grounds tor invoking
a waiver.
BALANCING CRITERIA
3 Long-Tenn Effectiveness
Refers to the abiSty of a remedy to maintain relaWe
protection of human heath and the environment over
time, once cleanup goals have been met
4 Reduction of Toxfcfty. Mobility, or Volume Through Treatment
Refers to me anticipated ab»y of a remedy to reduce the toxraty,
moMty, and volume of (he hazardous components present at the site.
5 Short-Term Effectiveness
Addresses both the period of time needed to complete the
remedy and any adverse impacts on human health and the
environment that may result from construction and
implementation of the remedy.
6 tmptomentibiNty
Refers to the technical and administrative feasibility of a
remedy, including the avaitabifty of materials and services
needed to construct and implement a particular remedy.
7 Cost
Evaluates the estimated capital, and operation and
maintenance costs of each alternative.
MODIFYING CRITERIA
8 State Acceptance
Indicates whether, based on its review of the
information, the state concurs with, opposes,
or has no comment on the preferred
alternative. Evaluated in the IROO.
it Community Acceptance
Indicates whether community concerns are addressed by the remedy and whether the
comrounrty has a preference for a remedy. Although pubfic £cwmeftt is an iipmtdiil
part of the final decision, the U.S. ERA is competed by law to balance community
concerns with all Bie previously mentioned criteria. Evaluated in the IROO.
Alternative 1: No Action
Alternative 2: Natural Attenuation and Monitoring
Alternative 3: Extraction, Treatment, and Disposal for Off-Base Remediation,
Source Control, and Migration Control
Figure 4-2. The Nine CERCLA Criteria
Travis AFB Groundwater IROD
As of 3 December 1997
81
-------
Table 4-1
T!
O
O
Comparison of Alternatives Versus the CERCLA Threshold and Balancing Evaluation Criteria
Alternative
No Action
(Alternative 1)
Natural
Attenuation/
Monitoring
(Alternative 2)
Extraction,
Treatment, and
Discharge
(Alternative 3)
(Treatment
Alternatives 3-9
in the FS)
Criterion 1
Overall Protection
of Human Health
and the
Environment
Does not protect
human health or the
environment
Provides some
protection of human
health and the
environment
Protects human
health and
environment in the
long term
Criterion 2
Compliance with
Laws and
Regulations
(ARARs)
Does not comply
with ARARs
May meet ARARs
in long term
Will meet ARARs
in the long term
(sooner than
Alternative 2)
Criterion 3
Long-term
Effectiveness and
Permanence
No long-term
effectiveness
Will have long-term
effectiveness from
natural attenuation
Most effective at
removing
contamination
Criterion 4
Reduction of
Toxicity, Mobility,
and Volume
through Treatment
No reduction from
action
No reduction from
active treatment
Will reduce
contaminant volume
and mobility
Criterion 6
Short-term
Effectiveness
No short-term
effectiveness
No short-term
effectiveness
Short-term
effectiveness
depends on removal
rate
Criterion 7
Implcmcntnbility
Easily implemented;
no equipment
needed
Is implementable;
minor equipment
needed
Technology is
implementable but
does require effort
to maintain system
and will have some
effect on base
operations
7>
O
D
OO
K)
Nuie: Criterion 5 (costs) are shown in Table 4-2.
ST
i
-------
Alternative 1 (No Action) will not comply with ARARs for groundwater, and without
monitoring there would be no way to determine when or if groundwater cleanup levels had been
achieved. Affected groundwater would have the potential to discharge to Union Creek.
4.2.2 Primary Balancing Criteria
4.2.2.1 Long-Term Effectiveness and Permanence
Alternative 3 would be the most effective at removing contamination from the
groundwater. Alternative 2 may be effective if natural attenuation is taking place at the selected
sites. Alternative 1 would be the least effective in the long-term since no steps are taken to
reduce risks, or monitor the reduction in risks.
4.2.2.2 Reduction of Toxiciry, Mobility, and Volume through Treatment
Only Alternative 3 would incorporate active treatment, and therefore it would reduce
the contaminant volume, and to some degree, contaminant mobility through hydraulic
containment. Alternative 1 would not reduce contaminant toxicity, mobility, and volume since it
does not include active treatment. Alternative 2 may reduce contaminant toxicity, mobility, and
volume although at a slower rate than Alternative 3.
4.2.2.3 Short-Term Effectiveness
Alternative 3 would remove contaminated groundwater, control the further spread of
groundwater contamination and would be the most effective alternative in the short-term.
Alternative 2 is not as effective in the short-term. This alternative is expected to take
longer than Alternative 3 to reach cleanup levels since it does not actively extract or treat
Travis AFB Groundwater IROD 83 as of 3 December 1997
-------
groundwater. Alternative 1 would be the least effective in the short-term since no steps are taken
to reduce risks, or monitor the reduction in risks.
4.2.2.4 Implementability
Alternative 1 would be easily implemented since no actions would be involved.
Alternative 2 would be implementable, and only minor additional equipment or monitoring wells
would be required. Alternative 3 would use available technology such as treatment equipment
and wells, but it would take time to design and install all of the required equipment. Because
Travis AFB is an active military Air Force installation, the installation and operation of this
equipment must be coordinated with base operations.
4.2.2.5 Cost
The Air Force estimated order-of-magnitude costs in the FS for each alternative
applicable for each site. The Air Force considered both capital costs and operation and
maintenance (O&M) costs. The Air Force estimated costs to be accurate to -30% to +50%, per
U.S. EPA CERCLA Guidance. The Air Force assumed a 5% discount rate, including the effects
of inflation, for present worth analysis, again based on the CERCLA Guidance. The Air Force
estimated costs only for the purposes of comparing alternatives according to the CERCLA
Guidance. Actual remediation costs could vary significantly from those in the FS and will be
determined in the remedial design phase. The Air Force calculated capital costs for each
alternative as separate components and then assembled as appropriate for each remedial
alternative. Component construction costs were calculated using the RACER/ENVEST™ cost
estimating model (version 3.1) (U.S. Air Force, 1993). The RACER/ENVEST™ model was
developed by the U.S. Air Force specifically for estimating costs of remediation approaches for
CERCLA documents, including FSs.
Travis AFB Groundwater IROD 84 as of 3 December 1997
-------
Table 4-2 shows the relative costs in thousands of dollars estimated in the FS of each
alternative as applied to the 15 different IRP sites within the NEWIOU (costs were calculated
separately for LF007B, LF007C, and LF007D). The treatment alternative with the lowest cost is
presented in Table 4-2. The cost presented for all alternatives is the capital cost plus the first year
of operating and/or monitoring. The cost of the different treatment technology trains depends on
the type, volume, and concentrations of the contaminated groundwater. The Air Force will
determine the actual costs for the selected altemative(s) during the remedial design stage
following signing of the IROD. Because all treatment processes are effective at removing
contaminants, the initial treatment processes used will depend on costs, which will, in turn,
depend on the volume and contaminant concentration of the extracted groundwater. The Air
Force would select the treatment plant locations during the remedial design stage. As
concentrations and volumes change with time, the Air Force could implement different treatment
processes if they are more cost-effective.
Alternative 1 has no cost. Alternative 2 has a low cost since it relies on labor and
analytical costs, and requires little additional equipment. The Air Force and regulatory agencies
assumed natural attenuation and monitoring costs to be constant at each site: three new
monitoring wells and analytical costs were assumed for four quarters. The Air Force will develop
the number and layout of monitoring wells and associated monitoring costs as part of the
site-specific RD. The costs shown for Alternative 3 are the lowest costs for the various treatment
alternatives evaluated in the FS. Alternative 3 costs more than Alternative 2 due to the capital
equipment required, and the comparatively high operation and maintenance costs.
4.2.3 Modifying Criteria
4.2.3.1 State Acceptance
State acceptance was not evaluated in the FS. Refer to Section 5.3.6 of the Groundwater
IROD for state acceptance discussion.
Travis AFB Groundwater IROD 85 as of 3 December 1997
-------
Table 4-2
Summary of Comparative Costs (thousands of dollars)
Site
FT004
FT005
LF006
LF007B
LF007C
LF007D
SS015
SS016
SS029
SS030
SD031
ST032
SD033
SD034
SS035
SD036
SD037
Alternative 1
No Action
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Alternative 2
Natural Attenuation/
Monitoring1
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
90
Alternative 3
Extraction, Treatment, and Discharge2
Capital Cost
915
1,800
640
550
450
1,800
750
2.8803
1,600
490
620
2,000
2,300
380
190
795
2,600
First Year O&M
280
260
61
72
58
224
120
2743
170
78
128
280
140
79
100
110
210
Total
1,200
2,100
700
620
510
2,000
870
3.2003
1,800
570
750
2,300
2,400
460
290
910
2,800
Natural attenuation/monitoring costs assumed to be the same for each site. The S90.000 estimates include SI8,000 in capital costs to install
monitoring wells and $72,000 in operational costs for the first year, mainly for sample analysis.
Costs for the Extraction alternative include the capital cost to build the system and one year of operating the system. All costs in thousands
of dollars. Costs were developed for KEWIOU FS and assume individual treatment plants for each site. The lowest cost estimate for all the
treatment alternatives evaluated in the FS is shown.
These costs are for Oil Spill Area portion of SS016, and do not include the "Remainder of Plume" costs which were calculated separately
in the FS.
Travis AFB Groundwater IROD
86
as of 3 December 1997
-------
4.2.3.2 Community Acceptance
Community acceptance was not evaluated in the FS. Refer to Section 5.3.6 of the
Groundwater IROD for community acceptance discussion.
4.2.4 Comparative Analysis
The FS presented quantitative, comparative analyses for the groundwater sites. The Air
Force and regulatory agencies factored the results of a sensitivity analysis into these conclusions.
The benefit/cost ratio and total effectiveness score were indicated for each representative
alternative for each group of groundwater sites.
The Air Force and regulatory agencies used a relative numerical rating system to
measure the degree to which an alternative fulfills each evaluation criterion. Subjective factors
and numerical values in a rating system evaluate how completely an alternative meets the
evaluation criteria (Table 4-3). The Air Force rated all criteria, with the exception of cost, with a
three number system of 5, 3, or 0. The cost criterion includes a four number system including 5,
3, 1, and -1. The addition of a fourth score for the cost criterion is included to provide for a wider
range of cost scores. These values are not absolute and served as a subjective ranking method for
the purpose of performing the comparative analysis. This rating system assumed that each of the
CERCLA criteria were equally important, since each are numerically weighted the same. This
may not always be representative in that certain criteria can have more importance, depending on
site-specific circumstances. For example, threshold factors must be achieved and therefore might
be seen as more important than a balancing factor, such as implementability. Despite these
factors, this unbiased scoring system was selected in the FS as the best method to consistently
evaluate all alternatives.
Travis AFB Ground water IROD 87 as of 3 December 1997
-------
Table 4-3
Remedial Alternative Evaluation Criteria Rating System
Evaluation Criterion
Protective of human health and the
environment
Compliance with appropriate
ARARs
Long-term effectiveness and
permanence
Reduction in toxicity, mobility,
and volume through treatment
Short-term effectiveness
Implementability
Cost
State acceptance
Community acceptance
Condition
Is protective
Potentially or contingent protection
Is not protective
Complies with appropriate ARARs
Complies with most appropriate ARARs or waivers needed
Does not comply
Once cleanup is completed, there is no recurrence potential
Contaminants transferred, future re-release possible
Contaminants not removed or destroyed
Eliminates toxicity, mobility, and volume
Reduces toxicity, mobility, and volume
No reduction or no treatment
Short-term environmental improvement protects human health
and the environment No risks (or only insignificant risks)
created by implementation
Limited short-term improvement in environment. Minor risks
created by implementation of alternative
No short-term improvement in environment. Significant risks
created by implementation
Alternative proven, all materials and personnel available,
permitting available or in place, little effect on operations
Alternative requires significant space, raises some
action-specific ARAR compliance issues, has some effect on
operations
Uncertain permitting, major impact on operations
<$1.5 million
$1.5 to 5 million
$5 to 10 million
>$10 million
To be determined (in the IROD)
To be determined (in the IROD)
Value
5
3
0
5
3
0
5
3
0
5
3
0
5
3
0
5
3
0
5
3
1
-1
NA
NA
' These final two criteria are typically evaluated following comment on the RI/F5 report and the Proposed Plan; and, therefore, were noi
scored in the FS.
ARARs = Applicable or Relevant and Appropriate Requirements
IROD = Interim Record of Decision
NA = Not Applicable
Travis AFB Groundwater IROD
as of 3 December 1997
-------
For the comparative analysis, two methods of quantitatively totaling the scores are
presented. The "Total Score" sums the seven criterion scores (i.e., all criteria except for the two
modifying considerations). A higher score indicates that more of the criteria were met. The
"Benefit/Cost Ratio" sums the scores of the five effectiveness criteria and divides by the
estimated cost, in millions of dollars. While the total score measures overall compliance with the
CERCLA criteria, the benefit/cost ratio better quantifies the degree to which CERCLA criteria
are satisfied per unit cost.
4.2.4.1 Total Score
The active treatment alternatives consistently had the highest total scores for all the
groundwater sites, with the differences in total scores between the different technologies not
being significant. The natural attenuation/monitoring alternative scored lower that the treatment
alternatives, but greater than the no action alternative.
4.2.4.2 Benefit/Cost Ratio
The benefit/cost ratios were more variable among alternatives. The natural
attenuation/monitoring alternative in some cases scored higher than the treatment alternatives,
and lower in other cases. The benefit/cost ratios were more favorable for Alternative 2 than the
treatment alternatives because the lower cost of natural attenuation/monitoring was a greater
factor in computing the benefit/cost ratio than in computing total cost.
4.2.4.3 Conclusion
The FS concluded that the active treatment alternatives, Alternatives #3 through #9,
have similar total scores and benefit/cost ratios, which is why these alternatives were later
consolidated into Alternative 3 in the PP and IROD. The natural attenuation/monitoring
alternative had lower total scores than the active treatment alternatives but often had higher
Travis AFB Groundwater IROD 89 as of 3 December 1997
-------
benefit/cost ratios because benefit is provided at a much lower cost. However, the benefit
(i.e., remediation) is often slower than with extraction and treatment.
The FS did not recommend implementation of specific alternatives for each site. The
FS provides information on the pros and cons of each alternative and site-specific factors to
consider when selecting site alternatives. The FS evaluated and compared the complete
implementation of each single alternative at each site, to provide maximum information to be
later used in selecting alternatives, or combinations of alternatives, at each site. The PP/IROD
process then performed a site-by-site analysis to develop selected alternatives.
FS Alternatives 3 through 9 were all found to be equally protective and effective for
remediating contaminated ground water depending on the type and concentration of contaminant
(i.e., petroleum products, VOCs, metals). Therefore, the Air Force has decided to determine the
most appropriate method of extraction treatment and discharge during the RD. This is discussed
further in Section 5.0 (Alternative 3).
Travis AFB Groundwatcr 1ROD 90 as of 3 December 1997
-------
5.0 INTERIM REMEDIAL ACTIONS
Travis Air Force Base (AFB) has selected interim remedial actions for the
North/East/West Industrial Operable Unit (NEWIOU) sites with groundwater contamination.
Section 5.1 presents the selected interim remedial actions and the rationale for the actions;
Section 5.2 describes the selected alternatives; and Section 5.3 presents the statutory
determinations.
5.1 Selected Interim Remedial Actions
The Air Force has developed interim remedial objectives for this Interim Record of
Decision (IROD) as shown on Table 5-1. A later, final ROD will include the final cleanup goals;
therefore, the Air Force has developed interim remediation goals (IRGs) to evaluate the
performance of implemented remedial alternatives during the five-year interim period. These
IRGs are similar to final cleanup levels but are not enforceable goals. The IRGs are shown on
Table 5-2.
Figure 5-1 shows the selected interim remedial actions for the NEWIOU groundwater
IROD. Table 5-3 shows these same interim remedial actions in table format. Table 5-3 lists the
15 NEWIOU Installation Restoration Program (IRP) sites with groundwater contamination. The
table includes site summary figure numbers and site names for reference. A checkmark indicates
the selected interim action for each site. If Alternative 3 (Extraction, Treatment, and Discharge)
is the selected interim action, the objective of the extraction is source control, migration control,
off-base remediation, or a combination of these.
Each of the selected remedies will protect human health and the environment, and
comply with ARARs. They will be effective at reducing contamination, and are implementable,
cost-effective, and acceptable to the public and the State of California.
Travis AFB Groundwater IROD 91 as of 3 December 1997
-------
Table 5-1
Interim Remedial Action Objectives for NEWIOU Groundwater IROD
Interim Remedial Action Objectives
1. Utilize an IROD, as opposed to a final ROD, to begin to quickly remediate groundwater contamination to
reduce contamination and risk, while collecting information necessary to allow for selection of final cleanup
levels and technically and economically feasible long-term actions.
2. Comply with NEWIOU ARARs.
3. Coordinate remedial actions with ongoing interim removal actions, e.g., the Tower Area Removal Action
(TARA)inSS016.
4. Consolidate sites whenever possible to cost-effectively treat groundwater, e.g., at FT005, SS029, and SS030.
5. Use treated groundwater on base whenever possible (i.e., for industrial or irrigation use) or discharge to
the sanitary sewer, if feasible.
6. Ensure any discharge of treated water to Union Creek meets substantive National Pollutant Discharge
Elimination System (NPDES) requirements.
7. Consider use of existing groundwater treatment plants, e.g., SS016, Outfall III treatment system.
8. Meet all Federal Facilities Agreement (FFA) dates.
9. Do not impact Travis AFB's mission.
Travis AFB Groundwater IROD 92 as of 3 December 1997
-------
Table 5-2
Interim Remediation Goals for NEWIOU Groundwater IROD
Chemical
Benzene
Bis(2-ethylhexyl)phthalate
Carbon Tetrachloride
Chlorobcnzcne
Chloroform
Chloromethane
1 ,4-Dichlorobenzene
Dichlorobromomcthane
1 ,2-Dichloroethane
1,1-Dichloroethene
cis- 1 ,2-Dichloroethene
1 .2-Dichloropropane
NapthaJene
Nickel
PCBs
2,3,7,8-Tetrachlorodibenzo-p-dioxin
Tecrachloroethene
TPH as Diesel
TPH as Gasoline
Trichloroethene
Vinyl Chloride
Xylenes
IRG
Concentration
(mg/L)
1.0x10-3(1)
4.0 x 10-3(1)
5.0x10-4(1)
7.0x10-2(1)
1.0x10-1(1). (2)
1.50x10-3(5)
5.0x10-3(1)
1.0x10-1(1), (2)
5.0x10-4(1)
6.0x10-3(1)
6.0x10-3(1)
5.0 x 10-3(1), (2)
2.0x10-2(4)
1.0x10-1(1)
5.0x10-4(1), (2)
3.0 x 10-8(1), (2)
5.0x10-3(1), (2)
1.0 x 10-1 (3)
5.0x10-3(3)
5.0 x 10-3(1), (2)
5.0x10-4(1)
2.0x10-2(3)
Applicable Sites
LF007, SS016, SS029, SD031, ST032*. SD034*. SD036,
SD037
FT004, FT005, LF007, SS015, SS016, ST032, SD034,
SD037
SD031.SD037
LF007
FT004, FT005, SSOI6, SS029, SS030, SD031
SD037
LF007, SS015, SS016
FT004, FT005, SS016, SS030, SD036, SD037
FT004, FT005, LF007, SS015, SS016, SS029, SS030,
SD031, SD033, SD036, SD037
FT004, LF006, LF007, SS016, SS029, SD031, ST032.
SD033, SD034, SD036, SD037
FT004, FT005, SS015, SS016, SS029, SD031, SD033,
SD034, SD036, SD037
LF007
SD037
FT004, FT005, SS015, SS016, SS030, SD031
LF007
LF007
SS015, SSOI6, SD034, SD036, SD037
LF006, SD033, SD034», SS035, SD036, SD037
SD033, SD034, SD036, SD037
FT004, FT005, LF006, LF007, SSOI5, SS016, SS029,
SS030, SD031, ST032, SD033, SD034, SS035, SD036,
SD037
FT004, LF007, SS015, SS016, SS029, SD031, SD034,
SD036, SD037
ST032
IRG - Interim Remediation Goal
mg/L » milligrams per liter
NE - Not Established
PCBs = Polychlorinated Biphenyls
TPH = total petroleum hydrocarbon
* Light Non-Aqueous Phase Liquid (LNAPL) or floating petroleum product has been detected at Sites ST032 and SD034.
IRGs are derived from the following:
(1) Drinking Water Standards - Maximum Contaminant Levels (MCL), California Department of Health Services, Primary MCL.
(2) Drinking Water Standards - MCLs, U.S. Environmental Protection Agency (U.S. EPA). Primary MCL.
(3) Other Taste and Odor Thresholds.
(4) Health Advisories or Suggested No-Adverse-Response Levels for toxicity other than cancer risk, U.S. EPA.
(5) Preliminary Remedial Goals, U.S. EPA.
Travis AFB Groundwater IROD
93
as of 3 December 1997
-------
I
o
S?
s
I
§
Depth to groundwatir •(
Tr»vl$ AFB range* from
a&ouf 5 feet In the north
to iboul 30 feet In the
*OUf/)Wtlt
Af 1997
Altarnatlv* 3
(OH-baat Ramadlatlon (•))
Alternative 3
(Souret Control (b))
Alltrnillv* 3
(Migration Control (e))
^rn Alternative 2
(Natural Altanuatlon/Monllorlng (d))
D*l*rr«d(•)
Off-Bait Prlvati WaUr Supply Wallt
(appronlmat* location*)
Figure 5-1. Selected / natives for NEWIOU
1RF Sites with GrouqtfMtpter Contamination
•••^M Travla AFB Boundary
Cl IRP Silt Boundary
-------
3
Table 5-3
I
1
Selected Interim Remedial Actions for NEWIOU IRP Sites with Groundwater Contamination
Associated
Figure
IRP Site
Site Name
Selected Interim Actions
Alternative 2
Natural
Attenuation/
Monitoring
Alternative 3
Extraction, Treatment,
and Discharge
Source Control
Migration Control
Off-base Remediation
Worth Operable Unit
Figure A-3
Figure A-4
Figure A-5
Figure A-6
LF006
LFOOTBf
LF007CT
LF007Df
Landfill 1
Landfill 2, Area B
Landfill 2, Area C
Landfill 2, Area D
X
»
*
(on-base portion
of plume)
*
X
(at base boundary)
X
(off-base portion of
plume)
East Industrial Operable Unit
Figure A- 1
Figure A-2
Figure A-7
Figure A-8
Figure A-9
Figure A- 10
Figure A- 1 1
Figure A- 12
FT004
FT005
SS015
SSOI6
SS029
SS030
SD031
ST032
Fire Training Area 3
Fire Training Area 4
Solvent Spill Area and Facilities 550 and 552
Oil Spill Area (OSA) and Facilities 1 1, 13/14, 18,
20, 42/1941, 139/144, and selected sections of
storm sewer right of way
Monitoring Well 329 Area
Monitoring Well 269 Area
Facility 1205
Monitoring Wells 107 and 246 Areas
*
*
•
(Plume A)
X
X
(OSA Area)
X
X
X
(bioslurp/free
product removal for
Plume B)
X
X
(southern plume)
X
X
X
X
s?
8
I
i
t As part of (he Rl and subsequently I he I'S, risks and remediation costs associated with contaminated groundwatcr were calculated for three areas in LF007; LF007B, LF007C, and LF007D.
• Selection of alternative for all or part of site is deferred until completion of the basewide natural attenuation assessment plan. Selected alternative will be documented in the basewide groundwater
ROD.
-------
i1
f
ex
H
3
§
O
Table 5-3
(Continued)
Associated
Figure
IRPSite
Site Name
Selected Interim Actions
Alternative 2
Natural
Attenuation/
Monitoring
Alternative 3
Extraction, Treatment,
and Discharge
Source Control
Migration Control
Off-base Remediation
West Industrial Operable Unit
Figure A- 13
Figure A- 14
Figure A- 1 5
Figure A- 16
Figure A- 17
SD033
SD034
SS035
SD036
SD037
Storm Sewer 11, Facilities 810 and 1917, South
Gate Area, and West Branch of Union Creek
Facility 811
Facility 818/819
Facility 872/873/876
Sanitary Sewer System, Facilities 837, 838, 919,
977, 981, Area G Ramp, and Ragsdale/V Area
*
(South Gate Area,
Facility 1917, and
Facility 810
plumes)
*
(complete Af CEE
Natural
Attenuation
• Study)
*
(portions of plume
near Facilities
919,977,981,
and Area G
Ramp)
X
(bioslurp/free
product removal)
X
(depending on
results of AFCEE
Natural Attenuation
Study)
X
(portions of plume
near Facilities 837,
838, and
Ragsdale/V Area)
X
(Storm Sewer)
X
(coordinated with
SD037)
X
(depending on results
of AFCEE Natural
Attenuation Study)
X
(remainder of plume)
VO
* Selection of alternative for all or part of site is deferred until completion ofthe basewide natural attenuation assessment plan. Selected alternative will be documented in the basewide groundwater
ROD.
5?
s
I
8
-------
5.1.1 Justification for Selected Interim Remedial Actions
The Air Force based the selection of interim remedial actions on the results of the
RI/FS process, as well as on previous removal actions, treatability studies, and pilot studies
conducted at Travis AFB. As discussed in Section 4.3.4.3, the FS provides the information to
select an alternative for each site but does not specify each selected alternative. The PP/IROD
process used the FS evaluation of each alternative at each site to select the interim remedial
action, or combination of actions, appropriate to each site. This selection process also considered
the interim nature of remedial actions under an IROD, as opposed to final actions under a ROD.
Appendix A presents additional detail on the rationale for selection of remedial actions at each
site. The Air Force eliminated the no action alternative because it does not adequately meet the
nine CERCLA criteria.
Alternative 3, Extraction, Treatment, and Discharge, will be used at specified sites to
reduce concentrations of groundwater contaminants and to remove floating petroleum product.
The goal is to attempt to achieve IRGs, but the Air Force will, at a minimum, continue the action
as necessary to prevent migration of the plume and will evaluate the level of cleanup that is
economically and technically achievable using Alternative 3. Alternative 3, is the selected
interim remedial action for sites where at least one of the following cases exists:
1. Off-base Remediation - Where dissolved VOC contamination extends
off-base.
2. Source Control - Where floating petroleum product or secondary sources of
VOC contamination (dense nonaqueous phase liquids [DNAPLs]) exist.
3. Migration Control - Where migration of contaminated groundwater is
confirmed.
For sites where none of the above criteria apply, the Air Force considered
Alternative 2, Natural Attenuation/Monitoring, as a possible interim action. Some portions of
Travis AFB Groundwater IROD 97 as of 3 December 1997
-------
groundwater plumes have low concentrations of contaminants; therefore, the contaminant plume
may be stable due to natural processes, but additional characterization is needed to make a
determination. In addition, some plumes have mixtures of VOCs and petroleum contamination,
which can facilitate the natural degradation of chlorinated solvents. Also, some plumes contain
breakdown products of TCE which may indicate that biodegradation is occurring. Although
conditions at the sites indicate the potential for natural attenuation, confirmation that the process
is taking place requires additional data and evaluation. Therefore, the interim remedial decision
for these sites is:
1. Select Alternative 2, Natural Attenuation, as the interim remedial alternative
for one representative site (LF006) to initiate a site-specific natural attenuation
evaluation because of evidence indicating that natural attenuation is occurring.
2. Defer the selection of an alternative for the remaining sites, or portions of sites,
until the Air Force obtains and evaluates additional data.
3. Initiate a basewide natural attenuation assessment plan to obtain the data for a
natural attenuation evaluation for the remaining sites, or portions of sites. The
evaluation at LF006 will develop Travis AFB's approach for this basewide
assessment plan.
The Remedial Action/Remedial Design (RD/RA) Work Plan for LF006 will address
placement of monitoring wells, protocols for monitoring, and evaluation procedures for
determining if the contaminated plume is stable (no significant migration above water quality
objectives). If natural attenuation is found to be inadequate to stabilize the plume, the Air Force
will implement a contingency action such as Alternative 3. The work plan will indicate a "trigger
point" based on methods such as modeling and statistical analysis that will indicate the need for
contingency action. The agencies will review and approve the work plan. If a contingency action
is necessary, the Air Force will not wait until the end of the five-year interim period. The Air
Force will request funding and implement the contingency action as soon as funding becomes
available.
Travis AFB Groundwater IROD 98 as of 3 December 1997
-------
Information obtained during the five-year interim period will be used to determine
whether natural attenuation and/or containment is the most technologically and economically
feasible final remedy. The Air Force will not allow horizontal or vertical migration of
contaminants along preferential pathways or within the aquifer at the natural attenuation sites
during the five-year period.
Travis AFB will proceed with interim remedial actions to begin quickly to remediate
groundwater contamination to reduce contamination and risk, while collecting information
necessary to allow for the selection of final cleanup levels and technically and economically
feasible long-term remedial actions in the final ROD.
5.1.2 Institutional Actions
The Air Force will use institutional actions for groundwater together with Alternatives
2 and 3 at all groundwater sites within the NEWIOU. The Air Force will place administrative
controls on the use of on-base groundwater from contaminated areas. Groundwater is not
currently used for drinking water at Travis AFB. The Air Force will place administrative controls
also on areas with groundwater contamination, restricting excavation and subsurface work where
the excavation worker will encounter groundwater or vapors emitted from the groundwater.
Excavation and work will only commence after the Air Force implements environmental and
worker safety control measures. Travis AFB already has a program to restrict contractors and
base personnel from digging in contaminated areas. This program requires that a digging permit
be obtained prior to any excavation activities. The Base Master Plan will cover any land use
restrictions, after the IROD proceeds to a final ROD.
The Air Force will implement alternative water supplies if monitoring identifies a threat
to off-base water supply wells. A contingency plan for alternative water supplies will be
incorporated into the RD/RA for sites with off-base plumes as a separate document. Groundwater
Travis AFB Groundwater IROD 99 as of 3 December 1997
-------
from beneath Travis AFB is not used for on-base water supply; therefore, the Air Force needs no
contingency plan for on-base water supply.
5.1.3 Groundwater Monitoring
Groundwater monitoring of all NEWIOU groundwater sites will continue during all
interim remedial actions to document the effect of the interim actions. Data will be evaluated on
a regular basis, with agency review, to determine the effectiveness of extraction remedies and to
evaluate natural attenuation. At all groundwater sites, if data indicates the plume is not stable, the
Air Force will initiate actions such as Alternative 3 to stabilize the plume. Appendix B contains
recommendations to the Travis AFB groundwater monitoring program for developing data for all
NEWIOU groundwater sites. The Air Force will consider these recommendations during the
interim remedial design task, and will revise the existing groundwater monitoring plan
accordingly. The GSAP annual report will be a primary document in accordance with the FFA.
The RD/RA work plan for each site will include details for monitoring and evaluation based on
site-specific conditions. Each work plan will address placement of monitoring wells, protocols
and frequency for monitoring, and evaluation procedures to determine if significant migration is
occurring. The agencies will review each of the site-specific RD/RA work plans, which are
primary documents in accordance with the FFA.
5.2 Alternative Description
This subsection summarizes the selected interim remedial actions. Site-specific
information on each alternative is provided in Appendix A.
5.2.1 Alternative 2 - Natural Attenuation/Monitoring
The Air Force has selected Alternative 2 (natural attenuation) for one site (LF006)
because the results from the RI/FS indicate a high probability that natural attenuation is an
Travis AFB Groundwaier IROD 100 as of 3 December 1997
-------
appropriate remedial alternative at this site. Additional characterization and field data will be
collected to confirm that plume migration is stable and that natural attenuation is effective at
LF006. The Air Force will implement Alternative 3 as a contingency action if natural attenuation
is not effective and the plume is not stable at LF006. The Natural Attenuation Assessment Plan
(NAAP) and the RD/RA Work Plan for LF006 will describe the specific details for
implementation of Alternative 2 and LF006. As described in Section 5.1, the Air Force has
deferred selection of the remedial alternative at other sites for entire plumes or portions of
plumes.
The Air Force will develop a NAAP Work Plan which is a primary document in
accordance with the FFA and will be submitted for approval to the regulatory agencies and will
include a separate schedule for implementation. Appendix B further discusses Alternative 2 and
elements of the NAAP.
The NAAP will be based on the AFCEE document "Technical Protocol for Evaluating
Natural Attenuation of Chlorinated Solvents in Groundwater" (Wiedemeier, et al, 1996). The
NAAP will describe the Air Force's approach for assessing natural attenuation at LF006, the
deferred sites, deferred portions of plumes, and will incorporate information from the AFCEE
pilot Study at SD036. The NAAP will describe how the Air Force will collect additional
information during the five-year interim period to evaluate the potential for selecting
Alternative 2 (natural attenuation) at the deferred sites and/or deferred portions of plumes.
The NAAP will include a schedule and a decision matrix that outlines the method to
determine which sites and/or portions of plumes are appropriate for remediation by Alternative 2
(natural attenuation). In reference to the sites where a portion of the plume is Alternative 3 and a
portion has the alternative selection deferred, the NAAP will clearly explain the methodology to
determine where the Air Force will apply Alternative 2 and Alternative 3.
Travis AFB Groundwater IROD 101 as of 3 December 1997
-------
The Air Force will modify the existing Basewide Groundwater Monitoring Plan as soon
as possible to include additional parameters, which will be useful in assessing the effectiveness
of natural attenuation.
The NAAP will provide a method to determine the migration rates for groundwater
contaminants at each site. The NAAP will establish a method to determine points of compliance,
locations for compliance wells, and a "trigger action" that initiates implementation of an
appropriate contingency action if natural attenuation is not effective at a site.
5.2.1.1 Definition of Natural Attenuation
"Natural Attenuation" refers to naturally-occurring processes in groundwater that act
without human intervention to reduce the mass, toxicity, mobility, volume, or concentration of
contaminants in those media. These in-situ processes include biodegradation, adsorption,
volatilization, and chemical or biological stabilization or destruction of contaminants. This
option includes monitoring to evaluate the affect of natural attenuation on contaminants in
groundwater, and to evaluate changes or migration of contaminated groundwater.
Monitored natural attenuation can be a viable method of remediation at some sites for
soil and groundwater. However, the Air Force will select natural attenuation only where it meets
all relevant remedy selection criteria, where it fully protects human health and the environment,
and where it meets remedial action objectives within a feasible time frame.
Monitored natural attenuation is not a "no action" or "walk away" option because the
Air Force must conduct adequate site characterization, monitoring and analysis to determine its
viability as a remedy. Once in place, the Air Force will perform continued monitoring to verify
that contaminant levels are decreasing as anticipated, and the remedy is protecting human health
and the environment.
Travis AFB Groundwater IROD 102 as of 3 December 1997
-------
Monitored natural attenuation does not have to be the only remedy component at a site
and it is typically combined with other types of remedies (such as source control or soil vapor
extraction), or used to complete remediation after other remedy components have cleaned up
most of the contamination and are no longer efficiently reducing contaminant levels. At Travis
AFB, the Air Force will assess each site to determine which plumes, or portions of plumes, the
Air Force can address by natural attenuation.
Travis AFB will perform a site-specific natural attenuation evaluation at the selected
natural attenuation site (LF006). The Air Force deferred the selected interim remedial alternative
of remaining "non-Altemative-3" sites, because the Air Force needs additional data to make a
proper selection of a remedial action. Therefore, Travis AFB will then perform a natural
attenuation evaluation at each of these sites similar to the evaluation at LF006. The goals and
contingencies of these evaluations will be the same as for the Alternative 2 (LF006) evaluation,
and will apply the results of the LF006 evaluation.
Travis AFB is considering the purchase of off-base land adjacent to Site LF007C.
Should the Air Force complete this purchase, then the selected interim remedial action for the
off-base portion of the plume will change from Alternative 3 to deferred (and will be included in
the basewide NAAP).
The Air Force will provide the monitoring data from all sites to the regulatory agencies
and the Restoration Advisory Board (RAB) for their review and comment. At sites where the Air
Force has assessed natural attenuation, the Air Force will also provide each site's data summary
and assessment report for review and approval. A formal review at the end of the five-year
interim period will address the acceptability of natural attenuation as a final cleanup action. After
this five-year review, a Basewide Groundwater Proposed Plan will present the preferred final
cleanup action (natural attenuation, pump and treat, or other) for each site. This Proposed Plan
will have a minimum 30-day public comment period. Following the Proposed Plan, a Basewide
Groundwater Record of Decision (ROD) will finalize the cleanup decision. The Air Force will
Travis AFB Groundwaier IROD 103 as of 3 December 1997
-------
submit the Draft Basewide Groundwater ROD to the agencies and the RAB for review and
comment. The regulatory agencies will review and approve the Draft Final Basewide
Groundwater ROD.
5.2.2 Alternative 3 - Extraction, Treatment, and Discharge
This alternative (also referred to as "pump and treat") cleans or controls the
contaminated plume by extracting contaminated groundwater. The Air Force will treat extracted
groundwater to comply with discharge standards shown on Tables 6-7 and 6-8. The final ROD
will include final cleanup goals in the final ROD; therefore, the Air Force has developed IRGs to
evaluate the performance of implemented remedial alternatives during the five-year interim
period. IRGs are shown in Table 5-2.
As part of Alternative 3, the Air Force will treat and discharge extracted groundwater.
Extraction, treatment, and discharge processes that will be used for the interim remedial actions
are described in the following sections.
5.2.2.1 Extraction Strategy and Technology
Extraction processes could include both horizontal and vertical extraction wells; Travis
AFB presently uses both types of wells at the base. Vertical wells with skimmer pumps could
also be used for floating product recovery. Bioslurping, two-phase, dual phase or soil vapor
extraction systems to remove soil gas, free product and/or groundwater may also be used. The
Air Force will assess specific site conditions, such as land use, plume size and concentration,
hydrogeology, soil permeability, and distribution of the contamination to determine the most
appropriate extraction technique. For example, most of Travis AFB has low permeability soils,
which result in limited production rates for vertical wells. Past experience at Travis AFB has
shown that high vacuum enhanced extraction can increase the production rate of such wells. For
higher permeability soils, experience at Travis AFB has shown that horizontal wells can
Travis AFB Groundwater IROD 104 as of 3 December 1997
-------
effectively remove groundwater from a large area. The Air Force will select the method of
extraction during the RD process.
5.2.2.2 Treatment Strategy and Technologies
One or more of the following treatment technologies will be implemented for treatment:
Air Stripping - Air stripping utilizes the volatility of many common organic
contaminants to remove them from the contaminated water and transfer them to the gaseous
phase. Air strippers may consist of towers with heights up to fifty feet, and with diameters from
several inches to several feet. Contaminated water enters the top of the tower while air blows
upwards through the tower. The agitation provided by the air and plates or synthetic media
within the column break up the water into small droplets, providing a large water surface-to-air
interface for organics to volatilize into the air phase. Treated water exits the bottom of the tower
while air carrying the organic contaminants exits the top of the tower. Depending on
concentration and local requirements, the contaminants in the air will usually require subsequent
treatment, consisting of thermal or catalytic destruction or adsorption onto activated carbon,
before discharge to the atmosphere.
Thermal and Catalytic Oxidation - Thermal and catalytic oxidation are two similar
processes that are used to destroy contaminants in process offgas streams, such as the air stream
from an air stripping tower or the effluent from a soil gas extraction blower. In a thermal
oxidation process, the contaminant gas is heated in the presence of air to a high temperature
sufficient to completely burn the contaminants and produce the combustion products of carbon
dioxide, water, and hydrochloric acid. Hydrochloric acid is formed only if chlorine is present in
the original contaminant. If a significant amount of hydrochloric acid is formed in this process, a
scrubbing unit is added. Thermal oxidation systems are economically favored if the contaminated
gas to be burned has a high fuel value, and the heat associated with burning the fuel can be
recovered.
Travis AFB Groundwater IROD 105 as of 3 December 1997
-------
Catalytic oxidation processes occur at lower temperatures than thermal oxidation
processes and can be economically favored if the gas to be treated has a low fuel value. A
catalyst is a material that accelerates a chemical reaction but is not itself consumed in the
reaction. A specially formulated catalyst may be required to operate in the presence of
hydrochloric acid, which would form from the oxidation of compounds such as TCE.
The target contaminant groups for catalytic oxidation are volatile and semivolatile
organic compounds (VOCs and SVOCs, respectively). For groundwater treatment, catalytic
oxidation would be the secondary technology in the treatment train. A primary treatment
technology (e.g., air stripping) would be required to transfer contaminants from the liquid phase
to the vapor phase prior to secondary treatment.
Activated Carbon - Activated carbon can be used to treat contaminated groundwater
for VOCs; the carbon is replaced or regenerated once the adsorbent is saturated. Activated carbon
is currently in use at Travis AFB and is effective in meeting discharge requirements for streams
with initial moderate VOC concentration (1,000 ppb). The target contaminant groups for
liquid-phase carbon adsorption are halogenated and non-halogenated semivolatile organic
compounds. The technology can be used, but may be less effective, in treating halogenated
VOCs, fuel hydrocarbons, pesticides, and inorganics.
The following factors may limit the applicability and effectiveness of liquid-phase
carbon adsorption:
• The solubility and concentration of the contaminants can impact process
performance;
• Metals can foul the system;
Travis AFB Groundwaier IROD 106 as of 3 December 1997
-------
Costs are high if used as the primary treatment on waste streams with high
contaminant concentration levels; and
Type and pore size of the carbon, as well as the operating temperature, will
impact the process performance.
Vapor phase carbon could also be used to adsorb VOCs from the air stream, and the
carbon filter would eventually need replacement or regeneration. The adsorptive capacity of
activated carbon significantly increases when it is used with vapor phase rather than with
aqueous phase contaminants. Vapor phase carbon has been used to remove VOCs from soil
vapor extraction (SVE) system effluent at Travis AFB.
Ion Exchange - The Air Force will use ion exchange systems or comparable
technology for metals removal if warranted. Ion exchange systems would be installed upstream
of the activated carbon and downstream of the air stripper. Specific polymeric resins
(or inorganic media) can be used to sorb specific suites of metals. In addition, ion exchange
affords some operating flexibility because regeneration of the resin can occur either
on- or off-site.
Ultraviolet Radiation and Oxidation - Ultraviolet Radiation and Oxidation (UV-OX)
is a liquid phase process and requires chemical reagents, such as hydrogen peroxide, promoted
with UV light, to destroy VOCs. Relative to an integrated system with an air stripper and
catalytic oxidizer, this method is equally effective and implementable, and the estimated costs
are comparable. However, this process option differs from an air stripper because there is no
generation (and required subsequent treatment) of an offgas stream. As with the air
stripper/catalytic oxidation system, an ion exchange unit followed by activated carbon will be
placed downstream of the UV-OX to provide for metals removal and final VOC treatment,
respectively. The target contaminant groups for UV oxidation are halogenated VOCs and
SVOCs, and pesticides. The technology can also be used, but may be less effective, in treating
Travis AFB Groundwaler 1ROD 107 as of 3 December 1997
-------
non-halogenated VOCs and fuels. The following factors may limit the applicability and
effectiveness of UV oxidation:
• The technology cannot be applied on all contaminants; and
• The presence of inorganics and naturally occurring soil organics (e.g., humic
substances) can adversely affect system performance.
Treatment Technology Selection
The above treatment processes present a "toolbox" of treatment options to use at sites
where the Air Force implements Alternative 3. The FS concluded that the treatment technologies
were all effective for treating contaminated groundwater. Therefore, the Air Force will select the
most appropriate method of extraction and/or treatment for each site selected during the RD.
The Groundwater NEWTOU RD/RA Work Plan will provide a description of the
overall rationale for treatment of contaminated groundwater. The Groundwater NEWIOU
RD/RA Work Plan will incorporate experience from ongoing removal actions and will include a
decision matrix that describes the procedure and rationale for selecting the appropriate
technologies at each site. There will be an opportunity for further public participation during the
Remedial Design phase.
5.2.2.3 Discharge
All treated groundwater discharges will comply with the discharge requirements of this
IROD as described in Section 6.0 and Tables 6-6, 6-7, and 6-8. Additional NPDES substantive
requirements will be established for each new discharge based on information provided during
the development of site-specific RD/RA work plans. This information will include, but is not
limited to, descriptions of treatment units with schematic drawings and design criteria, operation
and maintenance procedures, results of chemical analyses of untreated groundwater (influent) at
each site, projected maximum concentrations, projected flow rates, and topographic maps
Travis AFB Groundwater IROD 108 as of 3 December 1997
-------
showing exact locations of proposed discharges. Based on a review of this information, NPDES
substantive requirements for sampling, monitoring, and reporting will be established and
specified in the final site-specific RD/RA work plan which is a primary document in accordance
with the FFA.
The Groundwater NEWIOU RD/RA Work Plan will use the Treated Groundwater Use
Plan to estimate irrigation needs. The Groundwater NEWIOU RD/RA Work Plan will include a
decision matrix that outlines the rationale and method for treated groundwater discharge at
Travis AFB.
The RD/RA process, which includes agency review, will evaluate the volumes of
treated groundwater discharged to Union Creek to ensure there are no adverse effects on the
creek. For treated groundwater that is beneficially used on-base, the Air Force will meet the
effluent treatment limits of Table 6-8. Since discharge of treated groundwater to Union Creek
will always be a contingency to irrigation discharge, treatment methods will always be available
to ensure that treated groundwater from all sites can meet the discharge standards in Tables 6-7
and 6-8.
The additional treated groundwater that is produced after 1997 may be used for both
landscape irrigation and for industrial uses (aircraft wash water and car wash water). As interim
remedial actions are designed and implemented, the Air Force will use the Treated Groundwater
Use Plan to plan for the specific use of the additional treated groundwater.
Groundwater extraction and treatment will take place in phases, which will gradually
increase the amount of treated water available for use. By 1999, the Air Force may extract and
treat approximately 413 gpm (0.59 mgd) from contaminated groundwater sites. (The Treated
Groundwater Use Plan presents the assumptions used to derive this rate.)
Travis AFB Ground water 1ROD 109 as of 3 December 1997
-------
The Air Force will treat the extracted groundwater until contaminants have been
reduced to the discharge standards, as found in Tables 6-6, 6-7, and 6-8. Travis AFB may use the
treated groundwater for three possible general use options:
• Landscape irrigation al Travis AFB;
• Industrial uses such as car or aircraft washing; and
• Dust control during construction activities.
Travis AFB will discharge treated groundwater it cannot use in these options to the
sanitary sewer operated by the Fairfield-Suisun Sewer District, if feasible, or to surface water
(Union Creek). The figures in Appendix A indicate potential locations of discharge of treated
groundwater to Union Creek.
The options for using treated groundwater on base include irrigating the following
locations: Squadron operations; KC-10 maintenance facility; Grass areas, greenbelts, and
ballfields; and 200 Building Area. Potential industrial uses of the treated groundwater include
aircraft wash racks, car wash, motor pool, and above ground equipment.
Travis AFB will use most of the reused treated groundwater for irrigating landscape.
During the wet season, varying amounts of treated groundwater will be needed for irrigation,
depending on the rainfall and on when the wet season begins and ends. Consequently, Travis
AFB will discharge treated groundwater to the sanitary sewer, if feasible, or to Union Creek
during months of heavy precipitation.
5.3 Statutory Determinations
This section discusses the applicability and compliance of the following statutory
determinations:
Travis AFB Groundwater IROD 110 as of 3 December 1997
-------
• Protectiveness;
• Applicable or Relevant and Appropriate Requirements;
• Cost Effectiveness;
• Use of Permanent Solutions, Alternative Treatment, or Resource Recovery
Technologies;
• Preference for Treatment as a Principle Element;
• State and Community Acceptance.
5.3.1 Protectiveness
These selected remedies are protective of human health and the environment in the
short term, and the actions are intended to increase protection until the final Groundwater ROD is
signed. Protection is achieved by:
Remediating all off-site dissolved phase contamination to below the IRGs
through ground water extraction, treatment, and discharge;
Removing areas of contamination with floating petroleum products or VOC
concentrations greater than 3,000 ug/L using groundwater extraction, treatment,
and discharge;
Preventing migration of contaminated groundwater using groundwater
extraction, treatment, and discharge; and
Monitoring by the Air Force to confirm the stability of the plumes due to the
beneficial effects of natural attenuation.
5.3.2 Applicable or Relevant and Appropriate Requirements
The selected remedies comply with state and federal ARARs for this interim action.
Specific ARARs are included in Section 6.0.
Travis AFB Groundwater 1ROD 111 as of 3 December 1997
-------
5.3.3 Cost Effectiveness
The technologies selected in implementing Alternative 3 for extraction, treatment, and
discharge of contaminated groundwater will be the most cost-effective technologies from the
"toolbox" that can meet the RAOs and IRGs. The Air Force will determine these technologies
during the RD process.
The lower cost Alternative 2, Natural Attenuation/Monitoring, will be the most
cost-effective remedy at sites not requiring Alternative 3, if effective at stabilizing and/or
reducing the contaminated groundwater.
5.3.4 Use of Permanent Solutions, Alternative Treatment, or Resource Recovery
Technologies
The selected remedies utilize permanent solutions to the potential threats posed by
groundwater contamination at each of the sites to the maximum extent practicable. Use of
groundwater extraction, treatment, and discharge will control and remove contamination from
the subsurface permanently. Source control will remove and control contamination from the
highest concentration areas, while remediation of the dissolved off-base contamination will
remove contamination from areas outside the long-term control of the base. Natural attenuation
of dissolved chlorinated solvents is an innovative and alternative treatment technique that may
help remediate contaminated groundwater at the lower risk sites, while allowing the Air Force to
focus resources to achieve the maximum benefit at the lowest cost.
5.3.5 Preference for Treatment as a Principle Element
All of these remedies will effectively use passive or active treatment to address the
principal potential threats posed by contaminated groundwater. The Air Force will utilize the
Travis AFB Groundwater IROD 112 as of 3 December 1997
-------
operation of the groundwater extraction, treatment, and discharge options to maximize removal
of contamination from the groundwater to the extent practicable.
5.3.6 State and Community Acceptance
State Acceptance
The State of California (DTSC and SFBRWQCB) concurs with the Air Force and the
U.S. EPA in the selection of Alternatives 2 and 3 as the interim actions for the IRP groundwater
sites within the NEWIOU.
Community Acceptance
Based on the comments received during the public comment period, the public has no
preference of alternatives. The public comments received and the Air Force response is provided
in Part III (Responsiveness Summary).
5.4 RD/RA Implementation and Schedule
The Air Force will implement the RD/RA in accordance with this IROD. In accordance
with the Travis AFB FFA, within twenty-one days of signing the IROD, the Air Force shall
propose deadlines for completing the site-specific RD/RA work plans and RDs.
The RD/RA schedule will be included in the Groundwater NEWIOU RD/RA Work
Plan and is based on the Travis AFB IRP Priority Model. This model is a planning tool used by
Travis AFB to prioritize and schedule funding for IRP sites. Factors considered in this model
include human health risk, off-base migration, ecological risk, public interest, natural attenuation,
mass of contaminants, groundwater concentration, capital cost, project execution, and projected
funding levels.
Travis AFB Groundwaier IROD 113 as of 3 December 1997
-------
The Groundwater NEWIOU RD/RA Work Plan will address the following elements:
• RD/RA initiation and purpose;
• Travis AFB site prioritization and annual site work schedule;
• An extracted groundwater treatment technology decision matrix;
• A groundwater treatment and discharge decision matrix; and
• Five-year review to evaluate the effectiveness of the remedy
(five-year review will be the basis for establishment of final cleanup
levels, final ROD issuance, and eventual completion of site
cleanup).
Travis AFB will also develop a NAAP as described in Section 5.2.1 to assess the
effectiveness of natural attenuation and revise the groundwater monitoring plan to include
additional parameters needed to assess the effectiveness of natural attenuation. The NAAP will
establish long term groundwater monitoring requirements to assess the effectiveness of
Alternative 2. The existing Basewide Groundwater Monitoring Plan will be modified as soon as
possible to include additional parameters which will be useful in assessing the effectiveness of
natural attenuation.
Sites where the Air Force has selected Alternative 3 for using off-base dissolved plume
remediation will be given first priority, and design and installation of the groundwater extraction,
treatment, and discharge facilities will commence as soon as funding allows.
There is potential for contaminated groundwater to migrate along storm sewer lines and
other preferential pathways. The Air Force will implement Alternative 3 at some sites to control
migration of contaminated groundwater along preferential pathways. At other sites where the Air
Force has deferred the remedy selection until the final ROD, the Air Force will employ
monitoring and a contingency plan to ensure that preferential migration does not occur. At all
Travis AFB Groundwater IROD 114 as of 3 December 1997
-------
sites with known or potential interface between the storm sewer and contaminated groundwater,
the Air Force will investigate the interface during the RD. At locations where the Air Force has
found the contaminated groundwater to be migrating to the storm sewer or creek, the Air Force
will use an interim remedial action such as pump and treat to control migration. Where pump and
treat is used, the Air Force will monitor the effectiveness of this action; if the Air force finds that
the pump and treat action is not adequately controlling the migration, the Air Force will initiate a
contingency action such as repair or lining of the storm sewer.
As allocated funds become available, the Air Force will incorporate into the NEWIOU
groundwater remediation action the remaining sites where Alternative 3 has been selected for
migration control and source control. At SD036 AFCEE is currently conducting a natural
attenuation study. This study will evaluate the site using the AFCEE document "Technical
Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater"
(Wiedemeier, et. al., 1996). The Air Force will defer migration and source control interim actions
selected for this site until results of the study are reviewed, estimated to be late 1998. Based on
the results, the Air Force will implement or reevaluate the migration control and source control
interim actions.
5.5 Documentation of Significant Changes
There have not been any significant changes to the selected remedies since the Air
Force submitted the Proposed Plan for public comment on 25 September 1996.
Travis AFB Groundwater IROD 115 as of 3 December 1997
-------
6.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
AND PERFORMANCE STANDARDS
6.1 Overview
Under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), remedial actions designed to cleanup or abate contaminants in the groundwater, in
surface waters, or in soils, must be designed, constructed, and operated to comply with all federal
and more stringent state Applicable or Relevant and Appropriate Requirements (ARARs).
ARARs include federal requirements under any federal environmental laws and state
requirements under state environmental or facility-siting laws which are more stringent than
federal requirements, and that have been identified by the State of California in a timely manner.
Applicable requirements are those cleanup standards, standards of control, and other
substantive environmental protection requirements, criteria, or limitations promulgated under
federal environmental or state environmental or facility-siting laws that specifically address a
hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance at a
CERCLA site. Relevant and appropriate requirements include those that, while not "applicable"
to a hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance
at a CERCLA site, nevertheless address problems or situations sufficiently similar to those
encountered at the CERCLA site to indicate their use is well-suited to the particular site. If a
given requirement is both relevant and appropriate to a particular site, it constitutes a valid legal
requirement for that site. A requirement must either be applicable or both relevant and
appropriate to be an ARAR. If no ARAR addresses a particular situation, or if an ARAR is
insufficient to protect human health or the environment, then non-promulgated standards,
criteria, guidance, and to be considered (TBC) advisories are identified as additional performance
standards in the Record of Decision (ROD).
Travis AFB Groundwater IROD 116 as of 3 December 1997
-------
In general, on-site actions need comply only with the substantive aspects of these
requirements, not with corresponding administrative requirements (such as, but not limited to,
permits, recordkeeping, and reporting).
All laws and statutes identified as ARARs for a particular site or action must be
considered and applied during the design, construction, and operation of any remedial action at
the particular site. ARARs are identified on a site-specific basis from data and information
concerning that site. Data and information concerning the objectives of site remediation, specific
actions that are being considered as remedies at that site, the hazardous substances located upon
the site, the physical and geological characteristics of the site, and the potential human and
ecological receptors at or near the site must be analyzed and considered in order to properly
identify ARARs at a particular site. All federal and more stringent state requirements which
address or impact any of these conditions must be included as site ARARs.
There are three categories of ARARs. Some ARARs establish numerical values or
methodologies which, when applied to site-specific conditions, result in the establishment of
numerical values. Development of these ARARs (often referred to as chemical-specific ARARs)
involve the identification of contaminants at a site which pose a threat to human health or the
environment and must be remediated. Chemical-specific ARARs determine acceptable
concentrations of specific hazardous substances, pollutants, and contaminants in the environment
and establish the levels to which the ground or surface water at the affected site must be cleaned
or restored in order to protect human health and the environment. Chemical-specific ARARs also
establish the levels at which certain actions must be taken while transporting, treating, or storing
hazardous wastes recovered during remediation.
Other ARARs (referred to as location-specific ARARs) are designed to protect the
unique characteristics of the site or other areas potentially affected by site activities during the
design, construction, or operation of remedial activities. Location-specific ARARs place
restrictions on the concentration of hazardous substances or the conduct of activities solely
Travis AFB Groundwater IROD 117 as of 3 December 1997
-------
because the site occurs in, or may affect, a special location. Some examples include the
protection of wetlands and vernal pools; protection of endangered or threatened species and their
habitats; and the protection offish and game from unauthorized taking.
Still other ARARs (referred to as action-specific ARARs) are technologically or
activity-based requirements or limitations on the particular remedial actions at the site. Some
examples include prohibitions or restrictions against the discharge of chemicals or contaminants
to the air, water, or soil and the proper transfer, treatment, or storage of chemicals and
contaminants.
6.2 ARARs Identification. Development, and Evaluation
Methodology
As lead agency, the Department of the Air Force has performed each of the following
actions consistent with CERCLA and the National Contingency Plan (NCP):
Identified federal ARARs for each remedial action alternative addressed in the
Feasibility Study (FS), taking into account site-specific information for the
NEWIOU;
Reviewed potential state ARARs identified by the state in order to determine
whether each potential ARAR identified satisfied CERCLA and NCP criteria
that must be met in order to constitute state ARARs;
Evaluated and compared federal ARARs and their state counterparts in order to
determine which state ARARs are more stringent or are in addition to the
federal ARARs; and
Reached a conclusion as to which federal and state ARARs were the most
stringent and/or "controlling" ARARs for each alternative.
Travis AFB Groundwater IROD 118 as of 3 December 1997
-------
Solicitation, Identification, and Evaluation of State ARARs
The Department of the Air Force followed the procedures of the process set forth in
40 CFR Section 300.515 and the Federal Facilities Agreement (FFA) for remedial actions in
seeking state assistance in identification of state ARARs.
The CERCLA, NCP, and FFA requirements for remedial actions provide that the lead
federal agency request that the state identify chemical- and location-specific state ARARs upon
completion of site characterization, and again request identification of all categories of state
ARARs (chemical-, location-, and action-specific) upon completion of identification of remedial
alternatives for detailed analysis. The lead agency requested chemical- and location-specific
ARARs from the state agencies on 30 August 1995. Following submission of the Detailed
Analysis of Alternatives (DAA), the lead agency requested identification of ARARs to include
action-specific ARARs from the state agencies. The state responses included comments from:
• California Integrated Waste Management Board;
• Department of Toxic Substances Control Board;
• State Water Resources Control Board;
• California Regional Water Resources Control Board;
• Bay Area Air Quality Management District; and
• California Department of Fish and Game.
During the review and analysis of ARARs identified by the State, including the
Regional Water Board, and following considerable discussion with the representatives from the
various state agencies, many of the requirements identified by the state as potential ARARs were
determined to be valid ARARs by the lead agency. Upon completion of the FS, some issues
between the lead agency and the state concerning final groundwater cleanup levels had not yet
Travis AFB Groundwater IROD 119 as of 3 December 1997
-------
been resolved on the scope and/or applicability of several groundwater ARARs. These potential
ARARs will impact the duration of cleanup activity.
6.3 Interim Record of Decision Concept
Pursuant to Section 121(d)(l) of CERCLA, remedial actions must attain a degree of
cleanup which assures protection of human health and the environment. However, to expedite
remedial action, it was agreed between the Air Force and the regulatory agencies that the use of
an Interim Record of Decision (IROD) would be a prudent course of action. The IROD will
allow the implementation of remedial actions and associated reductions of contamination during
the period in which the establishment of final cleanup levels will be determined. The data
obtained from the interim remedial actions will play an integral part in establishing the factual
basis for establishing final cleanup levels. An evaluation of the interim actions will be made as
part of the CERCLA "five year review." Data obtained will be reviewed to determine the
effectiveness of the actions and changes in the actions will be made, if necessary. The additional
information obtained from these interim remedial actions should expedite the development of a
final ROD by providing documentation supportive of final cleanup levels that are protective,
realistic, and achievable.
6.4 Determination of ARARs for the Interim Action
Methodology
The list of ARARs identified in the North, East, and West Industrial Operable Unit
(NEWIOU) FS was used as a starting point for identifying groundwater ARARs. From that list,
those requirements applicable or relevant and appropriate to groundwater remediation were
identified for inclusion in the IROD, while those which had no relevancy to the interim
groundwater remediation were excluded from consideration. Specifically excluded were statutory
and regulatory provisions which:
Travis AFB Groundwaier IROD 120 as of 3 December 1997
-------
1. Were applicable or relevant and appropriate only to soils remediation sites;
2. Were applicable or relevant and appropriate only to action alternatives not utilized
in groundwater remediation actions;
3. Addressed location-specific conditions not present at groundwater remediation
sites; and
4. Established final cleanup standards.
The list of ARARs for NEWIOU groundwater remedial actions is provided in
Tables 6-1 through 6-5. The ARARs identified in Tables 6-1 through 6-4 are state ARARs and
are grouped by the state regulatory agency exercising regulatory authority over the particular
ARAR. Table 6-5 includes federal ARARs identified by the lead agency.
6.5 ARARs Evaluation and Discussion
Action-Specific ARARs
These ARARs place restrictions on remedial activities which may negatively impact the
surrounding environment. The potential NEWIOU groundwater remedial alternatives were
analyzed to identify potential impacts to the environment. Considered were:
Hazardous Waste Treatment, Storage, and Disposal — These requirements are
technology- or activity-based requirements which place limitations on actions taken with respect
to the hazardous waste. Regulations promulgated under the applicable provisions of the state
authorized federal Resource Conservation and Recovery Act (RCRA) and more stringent
provisions of the California Hazardous Waste Control Law (HWCL) are either applicable or
relevant and appropriate to RCRA-pemiitted storage facilities and proper characterization of
hazardous waste, and storage and disposal of such waste. If any hazardous wastes are identified
which will be transported off-site, they will be disposed of and handled under applicable
Travis AFB Groundwater 1ROD 121 as of 3 December 1997
-------
provisions of the state authorized federal RCRA program. Actions which might generate these
wastes include well installation (i.e., disposal of soils generated during construction) or active
treatment processes.
Many of the HWCL provisions are either applicable or relevant and appropriate because
they describe requirements for the safe handling of regulated materials and precautions for
preventing further contamination. These requirements are identified in Table 6-1.
Effects of Actions on Water Resources - Several California statutes and regulations
which protect the waters of the State have been identified and incorporated as ARARs. These
ARARs establish the remedial objectives and requirements for contaminants of concern (COCs)
present at NEWIOU groundwater remediation sites.
The Porter-Cologne Water Quality Control Act (PCWQCA) is one of the statutory
bases for regulation of discharges of waste to land that could impair either surface water or
groundwater quality in California. It establishes the authority of the State and Regional Water
Quality Control Boards to protect the quality of surface water and groundwater. Regulations
promulgated pursuant to the PCWQCA that have been determined to be either applicable or
relevant and appropriate are identified in Table 6-4. A further discussion of water remediation
requirements is included in the chemical-specific ARARs section below.
Effects of Groundwater Extraction - Portions of Union Creek adjoining sites SD001
and SD033 are considered to be both a floodplain and a wetland. Drainage ditches and a few low
lying areas at or near sites FT004, LF006, LF007, and SD031 are also considered wetlands.
Potential impacts resulting from removal of groundwater and the resultant lowering of the
groundwater table were considered. However, it has been determined that any change in
groundwater levels will not impact vernal pools or wetlands. The increased flow rates in Union
Creek due to the surface discharge of treated water was also considered and determined to not
significantly impact Union Creek.
Travis AFB Groundwater IROD 122 as of 3 December 1997
-------
Effects of Actions on Air Resources - State legislation divided the state into local air
pollution control districts and allowed each district to enforce the requirements of the state Clean
Air Act within its jurisdictional boundaries. Travis AFB is located in the Bay Area Air Quality
Management District (BAAQMD). The applicable air regulations incorporated into the IROD as
ARARs are identified in Table 6-3. In addition, most of these rules in the State Implementation
Plan (SIP) are adopted pursuant to the federal Clean Air Act, and these rules are federal ARARs.
That table contains the requirements, a brief description of the substantive requirements and the
applicability to either the site, remedial action, or technology used to clean up the site.
Technological Requirements for Remedial Equipment - The remediation of
groundwater at sites where Alternative 3 is the selected remedy will incorporate the use of a
combination ("tool kit") of five different technologies. These technologies include air stripping,
ultraviolet oxidation, catalytic oxidation, activated carbon adsorption, and ion exchange, and will
comprise the remediation "tools." One or more of these "tools" will be used at each site,
depending upon the particular facts of the site. The unique requirements triggered by each
technology and its associated equipment have been identified and are included as ARARs in
Tables 6-1 through 6-5.
Location-Specific ARARs
These ARARs place restrictions on remedial activities which may be conducted on-site
because of the presence of unique site features. The location of the NEWIOU groundwater sites
and surrounding areas were analyzed for unique site features to identify ARARs. The unique site
features considered were:
Habitats of Rare, Threatened, Endangered, and Special Status Species - Vernal
pools which contain an endangered species, including the Vernal Pool Tadpole Shrimp and the
Vernal Pool Fairy Shrimp have been identified at or near Site LF007. Other endangered species,
including the Black-Shouldered Kite, Boggs Lake Dodder, Burrowing Owl, Coopers Hawk,
Travis AFB Groundwater IROD 123 as of 3 December 1997
-------
California Gull, Golden Eagle, Loggerhead Shrike, Northern Harrier, Red Fox, Tri-colored
Blackbird, Contra Costa Goldfields, Northwestern Pond Turtle, and San Francisco Forktail
Damselfly have been observed at some time at Travis AFB and have the potential to be at
remedial sites.
Several federal ARARs were identified by impact to site ecology. The Endangered
Species Act and implementing regulations set forth in Table 6-5 apply to those remedial actions
at NEWIOU sites where impact to endangered wildlife could occur. The groundwater cleanup
activities are not expected to impact any endangered species; however, associated cleanup
activities (e.g., construction of pipelines for groundwater extraction) could affect these resources
should they be present. To ensure that regulatory requirements are followed and impacts are
avoided or mitigated, all sites will be surveyed for the presence of these resources immediately
prior to the commencement of remedial activities at the site.
Several state ARARs protective of site ecology have also been identified. The
California Fish and Game Code (CFGC) and regulations promulgated under this Code protect
rare, endangered, or threatened species or habitats, and require alternative actions at sites where
impacts have the potential to occur. In addition to these state counterparts to the Endangered
Species Act, the CFGC also establishes several requirements to protect site wildlife by
prohibiting or restricting the unauthorized taking of other wildlife. The CFGC also regulates to
protect aquatic life living in the waters of the state. All remedial activities that have the potential
to cause a discharge to any stream, lake, or other body of water must comply with the
requirements of the CFGC. CFGC ARARs are found in Table 6-3. United States Environmental
Protection Agency (U.S. EPA) does not concur that all CFGC requirements are more stringent
than federal requirements.
Historically or Culturally Significant Properties - Some buildings on Travis AFB
have recently been identified as Cold War Era buildings and historically significant. However,
none of these buildings are affected by NEWIOU remedial activities.
Travis AFB Groundwater IROD 124 as of 3 December 1997
-------
Wilderness Areas, Wild and Scenic Rivers, and Coastal Zones - No wilderness
areas, wild and scenic rivers, or coastal zones exist within the boundaries of Travis APB.
Therefore, requirements related to these areas are not applicable or relevant to NEWIOU sites
and actions.
Earthquake Faults - Although the Vaca-Winters and the Vaca-Kirby faults are located
in the Travis AFB area, NEWIOU sites are not located on these faults.
Chemical-Specific ARARs
Discharges of Treated Effluent - Surface water at Travis AFB includes Union Creek,
a minor tributary to the Suisun Marsh. Sites FT005, SS016, SS029, SS030, SD033, SD034,
SD036, and SD037 are located adjacent to Union Creek. However, design, construction, and
»
operation of remedial actions will not have an impact upon surface water. One of the options at
all sites for which groundwater treatment has been selected is the discharge of treated
groundwater to Union Creek. Provisions of 40 CFR Part 122 regulate discharge to surface
waters. National Pollutant Discharge Elimination System (NPDES) requirements establish
standards for discharges to surface waters of the United States. The substantive requirements of
federal or more stringent state ARARs for discharge to surface waters have been evaluated and
are included as ARARs. (See Tables 6-6, 6-7, and 6-8.)
State Water Resources Control Board Resolution 68-16 has been identified by the state
as an ARAR for the protection of both surface waters and groundwaters of the state. All parties
agree that Resolution 68-16 is an ARAR with respect to active discharges to surface water.
However, the United States Air Force and U.S. EPA do not agree with the state on the full
applicability of all the substantive requirements of this resolution and its impacts on the remedial
action activities. This disagreement will not impact the implementation of the interim
groundwater remedial actions at NEWIOU sites.
Travis AFB Groundwatcr IROD 125 as of 3 December 1997
-------
Reinjection of treated water into the ground water is not contemplated as part of the
remedial action.
Discharge of Effluent to Land - Irrigation is the designated beneficial use of treated
groundwater at Travis AFB. The use of reclaimed and treated groundwater for irrigation
activities shall meet the substantive standards set forth by the Regional Water Quality Control
Board order which establishes the general discharge requirements for treated groundwater. These
substantive standards ensure that reclaimed water is segregated from potable water sources and
does not migrate or escape from the area of irrigation. Standards for irrigation discharges are set
forth in Table 6-8.
Aquifer Remediation Objectives - For purposes of the IROD, State Water Resources
Control Board (SWRCB) Resolution 92-49, Section III.G is not an ARAR since final aquifer
cleanup levels are not being established in this IROD. The scope and applicability of SWRCB
Resolution 92-49 will be addressed in the final NEWIOU ROD.
Travis AFB Groundwater IROD 126 as of 3 December 1997
-------
Table 6-1
Federal ARARs* - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
* (California Statutes and Regulations Comprising Federal Authorized RCRA Program)
dwater IROD
Requirement,
Standard, or
Source Criterion Type Description RemarKs Sites and Alternatives
Title 22 CCR
Chap 1 2, Art 1
66262.11
Applicable
Requires a facility to make a determination as to
whether waste is hazardous.
Applicable to wastes excavated or
resulting from treatment processes.
004,005,007C,OI6,
029,030,031,032,
033, 034, 036, 037
3
Title 22 CCR
Chap 14, Art 6
66264.94
66264.96(c)
66264.97
Applicable
Applicable
Applicable
Establishes general groundwater monitoring
requirements and concentration limits.
Establishes monitoring requirements upon
removal of all waste and contaminated material
from a management unit. Requires monitoring
showing all levels in compliance with water
quality standards for three consecutive years.
Establishes groundwater monitoring requirements
during the closure and post-closure periods.
Relevant and appropriate at
groundwater site for development of a
comprehensive monitoring program
for the site.
004,005,007C,OI6,
029,030,031,032,
033, 034, 036, 037
3
to
-o
Title 22 CCR
Chap 14, Art 9
(Standards for
Owners and
Operators of
Hazardous Waste
Transfer,
Treatment,
Storage, and
Disposal
Facilities - Use
and
Management of
Containers)
66264.171
66264.172
66264.173
66264.174
66264.175
66264.176
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Sets standards for containers holding hazardous
waste for chemicals recovered from sediments,
surface soils, or groundwater.
Requires use of containers that are compatible
with the recovered material for the storage of that
material.
Requires containers used to transport material to
be closed during transport and that waste be
handled to minimize damage to containers.
Establishes requirements for inspecting
containers weekly.
Establishes requirement to ensure adequate
secondary containment for stored waste.
Requires isolating waste from sources of ignition
if waste is ignilable.
Sections in this article are relevant and
appropriate to sites or actions where
waste containers are used.
Containers will be used to transfer and
store wastes generated by
construction activities or the
operation of remedial actions.
Examples include spent carbon from
treatment plants, drill cuttings
from well installation, free product
removed from a plume, etc.
004,005,007C,OI6,
029,030,031,032,
033,034,036,037
3
e
o
"•»l
Ul
s?
s
$
-------
§
Table 6-1
Federal ARARs* - Ground water Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
(continued)
I c
H Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Title 22 CCR
Chap 14, Art 9
(cont'd)
66264.177
66264.178
Relevant and
Appropriate
Relevant and
Appropriate
Requires segregation of waste from
incompatible waste.
Establishes the requirement to remove all
hazardous waste and waste residue at closure.
Section 66264.178 is relevant and
appropriate when sites are closed and any
wastes or residue, as described above, are
on-site at closure.
Title 22 CCR
Chap 14, Art 10
Standards for
Owners and
Operators of
Hazardous
Waste Transfer,
Treatment,
Storage, and
Disposal
Facilities - Use
and Management
of Tank Systems
66264.192
66264.193
66264.194
66264.195
66264.196
66264.197
66264.198
66264.199
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Establishes design/installation requirements for
new tank systems and components.
Delineates requirements for tank systems
including containment and detection of releases.
Delineates requirements for tank systems
including general operating requirements.
Delineates requirements for tank systems
including inspections.
Delineates requirements for tank systems
including response to leaks or spills.
Delineates requirements for tank systems
including closure and post-closure care.
Delineates requirements for tank systems
including special care requirements for reactive
wastes.
Delineates requirements for tank systems
including special requirements for incompatible
wastes.
Sections in this article are relevant and
appropriate to alternatives which
incorporate the use of tanks or tank
systems as part of the remedial equipment.
Tanks will be used at treatment plants to
store contaminated water prior to
treatment. Tanks will also be used for
temporary storage of free product, if
necessary.
Alternatives which utilize tanks or tank
systems include UV oxidation, air
stripping, activated carbon adsorption,
catalytic oxidation, and ion exchange
technologies.
Section 66264.197, paragraphs (a), (c)(3),
and (c)(4) are not relevant and appropriate
with respect to cost estimates and financial
responsibility requirements.
Section 66264.198 is relevant and
appropriate to sites with ignilablc wastes
(i.e., free product) or reactive waste.
Remedies utilizing reactive oxidizers, such
as ultraviolet oxidation or catalytic
oxidation, would trigger this requirement.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
NJ
oo
R
o
8
?r
i
-------
Table 6-1
Federal ARARs* - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
(continued)
§
D
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Title 22 CCR
Chap 1 4, Art 13
Incinerators
66264.341
66264.342
66264.343
66264.344
66264.345
66264.347
66264.351
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Requires analysis of the waste feed sufficient to
provide all information required by section
66270.62(b) or 66270. 19.
Requires Principal Organic Hazardous
Constituents (POHCs) in the waste feed be
treated to the extent required by the performance
standard of section 66264.343.
Establishes maintenance, construction, and
design requirements to ensure proper operation.
Establishes types of waste which can be burned
and operating conditions for those wastes.
Requires incinerators be operated in accordance
with operating requirements.
Establishes monitoring during hazardous waste
incineration.
Establishes closure requirements for the
incinerator site and residual wastes.
Applicable to all sites where catalytic
oxidation may be used to treat vapor
phase contaminants. The permitting
requirements of sections 66264.343,
66264.344, and 66264.345 are not
ARARs.
Only substantive requirements of section
66264.344, subsection (a) are ARARs.
004, 005, 007C.
016,029,030,
031,032,033,
034, 036, 037
3
NJ
Title 22 CCR
Chap 14, Art 16
66264.601
66264.602
66264.603
Applicable
Applicable
Applicable
Specifies performance standards for
miscellaneous units that transfer, treat, store or
dispose of hazardous waste.
Establishes analysis, inspection, response,
reporting, monitoring, and corrective action
standards for miscellaneous units.
Establishes maintenance standards for
miscellaneous units.
Applicable at Travis AFB sites where air
strippers are used as part of the remedial
action.
Section 66264.602 requirements related
to response and reporting procedures are
procedural and do not apply.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
K
o
I
-------
3*
'
i1
§
a
Table 6-1
Federal ARARs* - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
(continued)
Source
Requirement,
Standard, or
Criterion
Type
Description
Remarks
Sites and Alternatives
Title 22 CCR
Chap 14, Art 27
(Air Emission
Standards for
Process Vents)
66264.1032
66264.1033
66264.1034
66264.1035
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Establishes emission limits when process
vents are used.
Establishes standards for closed vent systems
and control devices.
Establishes test methods and procedures for
closed vent systems.
Establishes recordkeeping requirements for
closed vent systems and parameters for
design analysis and performance.
Relevant and appropriate to alternatives
where closed vent systems are used.
At NEWIOU groundwater sites, this would
include remediation systems which
have vents in the system to include air
strippers, UV oxidation and catalytic
oxidation equipment, and carbon treatment
vessels.
004, 005, 007C,
016, 029, 030,
031,032,033,
034, 036, 037
3
Title 22 CCR
Chap 14, Art 28
(Air Emission
Standards for
Equipment Leaks)
66264.1054
66264.1063
66264.1064
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Establishes that pressure relief devices in
gas/vapor service shall be operated with no
detectable emissions.
Establishes leak detection monitoring
requirements.
Establishes recordkeeping requirements for
gas/vapor extraction systems.
Relevant and appropriate for actions where
gas/vapor extraction systems are used.
Actions include air stripping, activated
carbon adsorption, and catalytic oxidation
equipment.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
Title 22 CCR
Chap 18, Art 1
(Land Disposal
Restrictions -
General)
66268.3
66268.7
66268.9
Applicable
Applicable
Applicable
Establishes land disposal restrictions,
including a prohibition of using dilution as a
substitute for treatment.
Establishes land disposal restrictions,
including requirements for waste analysis
and recordkeeping.
Establishes land disposal restrictions
including special rules for wastes that exhibit
a characteristic.
Applicable to hazardous wastes generated
from site construction activities. Places
restrictions on site disposal activities in
unauthorized areas. Section 66268.7,
paragraphs (a)(l), (b)(l), (2), and (3), and
(c)(2) are substantive requirements. The
remainder of the section is procedural and
not ARARs.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
R
2,
U)
-------
Source
o
Table 6-1
Federal ARARs* - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
(continued)
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Title 22 CCR
Chap 1 8, Art 2
All Sections
Applicable
Establishes treatment technology for disposal
of waste lo land for RCRA and non-RCRA
wastes identified in Section 66268.106.
Applicable to sites where material or
secondary waste from construction activities
(includes excavation for well installation,
pipeline installation, and foundations for
treatment facilities), or excavation material
is classified as hazardous or state regulated
waste. Wastes identified will be managed in
accordance with these standards using the
characterization process.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
Title 22 CCR,
Chap 18 Art 3
(Prohibitions on
Land Disposal)
66268.30
66268.31
66268.32
66268.33
66268.34
66268.35
66268.36
66268.37
66268.38
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Establishes waste-specific LDRs.
Establishes LORs for wastes containing
dioxin.
Establishes LORs for certain hazardous
wastes.
Establishes LDRs - First Third Wastes.
Establishes LDRs - Second Third Wastes.
Establishes LDRs - Third Third Wastes.
Prohibits land disposal of newly listed wastes.
Prohibits land disposal of ignitable and
corrosive characteristic wastes whose
treatment standards were vacated.
Identifies waste specific prohibitions on newly
identified organic toxicity characteristic
wastes and newly listed coke by-product and
chlorotoluene wastes.
Applicable to groundwater remediation
sites where media excavated for equipment
installation is classified hazardous waste
and disposed of or treated on-site. Requires
identification of waste through the proper
characterization process.
004, 005,
007C, 016,029,
030,031,032,
033, 034, 037
3
B
o
sr
-------
f
o
c
I
JO
O
O
Table 6-1
Federal ARARs* - Groundwater Remediation (IROD)
Waste Transfer, Treatment, and Storage and Disposal Requirements
(continued)
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
to
Title 22 CCK
Chap IS, Art 4
Title 22 CCR
Chap 18, Art 5
Title 22 CCR
Chap 18, Art 10
Title 22 CCR
Chap 18, Art 11
All Sections
All Sections
66268.100
All Sections
Applicable
Applicable
Applicable
Applicable
Identifies treatment standards for halogenated organic
compounds regulated by Section 66268.32.
Establishes prohibitions on storage of hazardous
wastes restricted under Article 3 of this chapter or
RCRA Section 3004 (42 USC 6924).
Establishes land disposal prohibitions for non-RCRA
hazardous wastes.
Establishes disposal restrictions, prohibitions, and
treatment standards for certain identified hazardous
wastes.
Applicable to sites where excavated
material is classified as hazardous
waste. Identified waste
will be managed in accordance with
these standards. Applicable at
groundwater sites where contaminated
soils are excavated in order to install
remediation equipment.
004, 005. 007C,
016,029,030,
031,032,033,
034, 036, 037
3
Title 22 CCR
Chap 43
(Management of
Extremely
Hazardous
Wastes)
67430.3
Applicable
Establishes requirements for the removal of spilled or
improperly deposited extremely hazardous wastes.
Applicable to NEWIOU groundwater
sites where unintentional spills may
occur.
004, 005, 007C,
016.029,030,
031,032,033,
034, 036, 037
3
D
n
R
I
-------
i
I
53
8
Table 6-2
State ARARs - Groundwater Remediation (IROD)
Air Remediation Requirements
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Regulation
2, Rule 1
(Bay Area
Air Quality
Management
District
Regulations)
308
316
501
Applicable
Applicable
Applicable
Establishes that fugitive emissions '
from equipment or facilities must
comply with all applicable
requirements.
Establishes maximum levels for
toxic air contaminants, which, if
exceeded, require a risk screening
analysis.
Establishes that continuous emission
monitors meet certain requirements.
Applicable to actions where air strippers or other systems using
pressurized components (UV oxidation, carbon adsorption,
catalytic oxidation, and ion exchange) could result in fugitive
VOC emissions.
Applicable to actions which have the potential to emit toxic air
contaminants (e.g., TCE). Substantive provisions are applicable
to actions including air stripping, UV oxidation, carbon
adsorption, catalytic oxidation, and ion exchange.
Applicable to all sites or actions where air stripping, UV
oxidation, carbon adsorption, catalytic oxidation, and ion
exchange technologies are used in the remedial action.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
Regulation
2, Rule 2
112
301
Applicable
Applicable
Establishes exemptions for
emissions of secondary pollutants
from abatement control equipment
which complies with BACT or
BARCT requirements.
Establishes BACT requirement for
new sources which emit in excess of
10 Ibs per day of precursor organic
compounds, non-precursor organic
compounds, NO,, SO,, PM10 or C02.
Applicable to actions where BARCT or BACT abatement
devices are used (i.e., carbon adsorption is used together with
catalytic oxidation or UV oxidation or ion exchange) but where
secondary emissions from the abatement equipment still exist.
Applicable to all actions with potential to discharge to air. Not
applicable for permitting requirements or authority to construct
but applicable for determining the applicability of BACT to a
new source. Remedial alternatives using air strippers must
ensure BACT is used (i.e., air stripping, catalytic oxidation with
carbon adsorption) to control emissions in excess of levels
specified in the rule.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
U)
u>
R
o
-------
r
Table 6-2
State ARARs - Groundwater Remediation (IROD)
Air Remediation Requirements
(continued)
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Regulation 6
301
302
303
501
Applicable
Applicable
Applicable
Applicable
Establishes limitations on visible
emissions and opacity.
Establishes limitations on opacity.
Establishes limitations on emission
rates, concentration, visible
emissions, and opacity.
Establishes requirements for
sampling facilities and instruments.
Applicable to sites where excavation or construction activities
have the potential to release paniculate matter into the air
(i.e., dirt and dust), or at sites where portable soldiering,
brazing, welding equipment is used. Also applicable at sites
where portable combustion engines of < 25 liters of
displacement are used.
Applicable to all actions subject to Regulation 6.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
1
R
o
""»
w
5?
5T
-------
Table 6-3
State ARARs - Groundwater Remediation (IROD)
Fish and Game Requirements
o
3
a
ex
I
§
o
Source
Requirement,
Standard, or
Criterion
Type
Description
Remarks
Sites and Alternatives
California
Fish and
Game Code
1908
2080
2091
2092
3005
3511
3513
5050
5515
5650
Applicable
Applicable
Relevant and
Appropriate
Relevant and
Appropriate
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Prohibits the import, taking or possession of rare
or endangered native plants.
Prohibits the import, taking or sale of threatened
or endangered native plants.
Requires state agencies to use alternative actions
where impact to threatened or endangered species
or habitat is found.
Requires state agencies to adopt reasonable
alternative actions where project would result in
the extinction of a species.
Prohibits taking of birds or animals with net,
pound, cage, trap, set line, wire, or poison.
Prohibits taking of birds identified as "fully
protected."
Prohibits Inking or possession of mammals
identified as "fully protected."
Prohibits taking or possession of reptiles and
amphibians identified as "fully protected."
Prohibits taking or possession of Fish identified as
"fully protected."
Prohibits deposit or placement of specified
materials and substances into places where it can
pass into the waters of the state.
Applicable to active groundwater remediation sites
where rare or endangered native plants exist.
Requires site surveys prior to action to determine
presence of endangered/threatened plants at the
site and consideration of potential impact at sites
where impact to endangered or threatened species
may occur. Will be considered at all groundwaler
sites where active remediation occurs.
Applicable at all groundwater remediation sites
where birds, animals, or other wildlife identified
by the applicable statutory provision exist.
Applicable to all groundwater remediation actions or
sites where substances have a pathway to state
waters.
004, 005.
007C.OI6,
029.030,031.
032, 033, 034,
036, 037
3
R
o
-------
i
55
o
o
Source
Table 6-3
State ARARs - Groundwater Remediation (IROD)
Fish and Game Requirements
(continued)
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
California
Fish and
Game
Policies
Manage-
ment and
Utilization
of Fish and
Wildlife on
Federal
Lands
Wetlands
Resource
Policy
Performance
Standard
Performance
Standard
Establishes management policies and
defines methodologies used in
protecting all fish, wildlife, and
threatened and endangered species.
Establishes management policies and
defines methodologies to assure no net
loss of wetland habitat value or
acreage.
Although these policies are not promulgated regulations and
therefore, cannot be legally defined as ARARs, these policies
do contain substantive provisions which will be relied upon
in the decision process, consistent with applicable federal
laws and statutes. Will be followed at all groundwater sites
where active remediation occurs.
The Wetlands Resource Policy will be followed at sites
where wetland habitat occurs.
004, 005, 007C.
016,029,030,
031,032,033,
034, 036, 037
007, 033
3
3
Title 14
CCR
40.00
40.10
460
640
670.2
670.5
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Prohibits the taking of possession of
native reptiles and amphibians.
Prohibits the taking of possession of
native reptiles and amphibians.
Prohibits the taking of certain fur
bearing mammals at any time.
Establishes requirement for fish and
wildlife planning to optimize fish and
wildlife resources.
Establishes species, subspecies, and
varieties of native California plants as
endangered, threatened, or rare.
Establishes species, subspecies, and
varieties of native California plants as
endangered, threatened, or rare.
Applicable to all site and action alternatives where identified
mammals, fish, reptiles or amphibians, or plants exist.
Will be considered at all groundwater sites where active
remediation occurs.
Requires site surveys prior to action to determine presence of
endangered/threatened plants at the site.
Species found at Travis AFB which are covered by these
sections include the Black-Shouldered Kite, Boggs Lake
Dodder, Burrowing Owl, Coopers Hawk, California Gull,
Golden Eagle, Loggerhead Shrike, Northern Harrier, Red
Fox, Tri-colored Blackbird, Vernal Pool Fairy Shrimp,
Contra Costa Goldfields, Northwestern Pond Turtle, San
Francisco Forktail Oamselfly, Vernal Pool Tadpole Shrimp.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
K
o
**»
UJ
S?
R
I
-------
Table 6-4
State ARARs - Groundwater Remediation (IROD)
Water Board Requirements
Source
Requirement,
Standard, or
Criterion
Type
Description
Remarks
Sites and Alternatives
Federal Water
Pollution Control
Act Section 402,
Porter Cologne
Water Act;
California Water
Code, Division 7,
Sections 13000,
13140, 13240,
Water Quality
Control Plan for
the San Francisco
Bay Basin
SWRCB
Resolution
68-16
Applicable
Establishes policy that whenever the existing quality of
water is better than the quality established in policies as
of the date on which such policies become effective,
such existing high quality will be maintained until it
has been demonstrated that any change will be
consistent with maximum benefit to the people of the
State, won't unreasonably affect present and
anticipated beneficial use of such water and will not
result in water quality less than prescribed in the
policies. Discharges or proposed discharges to existing
high quality waters will be required to meet waste
discharge requirements which will result in the best
practicable treatment or control of the discharge
necessary to assure that a pollution or nuisance will not
occur and the highest water quality consistent with
maximum benefit to the people of the State will be
maintained.
Applicable to sites where groundwater
IROD actions will cause active
discharges to surface water (i.e.,
Union Creek). The lead agency, U.S.
EPA, and water board agree to
disagree as to the applicability of this
section with respect to passive
discharge and plume migration.
Throughout the IROD, plumes at
these sites will be monitored and
evaluated to ensure migration is not
present.
San Francisco Bay Region Order
Number 94-087 establishes
requirements for discharge or reuse of
extracted and treated groundwater
which was contaminated by VOCs.
Contaminants in treated groundwater
shall not exceed the more stringent of
the substantive standards set forth in
Order 94-087, MCLs, or such levels
necessary to preclude degradation of
the receiving water quality. The
numeric effluent limitations for
discharges to treated water that
comply with Resolution 68-16 are
specified in Table 6-6. The discharge
must also comply with paragraphs
A.I, A.2, and A.3 (prohibitions) of
General Waste Discharge Order
94-087.
004, 005, 007C,
016.029,030,
031,032.033,
034, 036, 037
3
-------
i"
1
Table 6-4
State ARARs - Ground water Remediation (IROD)
Water Board Requirements
(continued)
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Regional Water
Quality Control
Board, San
Francisco Bay
Area
RWQCB
Resolution
88-160
Applicable
Urges the dischargers of extracted groundwater from
groundwaler cleanup projects to reclaim their effluents
to the extent technologically and economically
feasible, and if not technologically and economically
feasible, urges discharge to POTWs. Where neither
reclamation or POTW discharge is technically or
economically feasible, discharge in accordance with
NPDES requirements will be authorized by the board.
Applicable to all groundwater sites
where groundwater extraction
occurs. Board NPDES permitting
requirements identified by the
resolution are procedural and not
ARARs. The reused water must
comply with para D of General
Waste Discharge Order 94-087 and
effluent treatment levels listed in
Table 6-8.
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
u>
00
Title 23 CCR
Chapter 15
(CWC Sections
13140- 13147,
13260, 13263,
13267, 13304)
2511(d)
Relevant
and
Appropriate
Establishes exemption from provisions of this
subsection for actions taken by/at the direction of
public agencies to clean up or abate conditions of
pollution resulting from unintentional or unauthorized
releases of waste or pollutants to the environment.
Requires wastes, pollutants, or contaminated materials
removed from the immediate place of release to be
discharged according to Art 2. Remedial actions
intended to contain such wastes at the place of release
shall implement provisions of this subchapter to the
extent feasible.
Relevant and appropriate to
monitoring requirements and other
specific actions which are not related
to final cleanup levels or goals at
both sites where active remediation
will occur and where natural
attenuation has been selected as the
interim remedy.
006,007
2,3
R
o
«»
U)
-------
9
o
c
3
Q.
§
o
Table 6-4
State ARARs - Groundwater Remediation ((ROD)
Water Board Requirements
(continued)
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Regional Water
Quality Control
Board
S.F. Bay
Basin Water
Quality
Control
Plan,
Chapter 2,
Beneficial
Uses
S.F. Bay
Basin Water
Quality
Control
Plan,
Chapter 3
(Water
Quality
Objectives)
Applicable
Applicable
Establishes beneficial uses of surface waters
of the state.
Establishes discharge to surface water
requirements, including receiving water
quality objectives and receiving water limits.
Applicable to define beneficial uses of
surface waters where treated effluent may be
discharged. Beneficial uses of Union Creek
and downstream receiving waters include
navigation, contact and non-contact
recreation, fish spawning, warm fresh-water
habitat, and wildlife habitat.
Applicable where effluent is discharged to
surface water. Surface waters shall not
contain concentrations of constituents in
amounts that affect any beneficial use or the
objectives for selected toxic pollutants
identified in Tables 3-3 and 3-4. Incorporates
requirements of General Order 94-087,
paragraph C (receiving water limitations for
discharges to surface water • see Table 6-7)
and paragraph F.5 (prohibitions on
radiological, biological, and chemical
warfare agent waste).
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
3
u>
U.S. Office of
Solid Waste
RCRA
Ground
Water
Monitoring,
Draft
Technical
Guidance,
Nov. 1992
(EPA /530-
R-93-001
Performance
Standard
Sets forth requirements for the development
of a groundwater monitoring program.
Applies to the development of a
comprehensive monitoring program for the
site (also reference Table 6-1, 22 CCR
Section 66264.94, 66264.96, and 66264.97).
004, 005, 007C,
016,029,030,
031,032,033,
034, 036, 037
*
3
R
o
—>
Ul
5?
s
I
i
-------
00
I
Table 6-5
Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Title 16 USC
(Endangered
Species Act)
Title 50 CFR
1531(c)
1536(a)
Part 402
Applicable
Applicable
Applicable
Requires action to conserve
endangered species and critical
habitats upon which endangered
species depend. Includes consultation
with the Department of Interior to
gather substantive information
necessary to ensure compliance with
this requirement.
Activities at all remedial sites must be performed in
such a manner as to identify the presence of and
protect endangered or threatened plants and animals
at the site. Species present at Travis AFB include the
Black-Shouldered Kite, Boggs Lake Dodder,
Burrowing Owl, Coopers Hawk, California Gull,
Golden Eagle, Loggerhead Shrike, Northern Harrier,
Red Fox, Tri-colored Blackbird, Vernal Pool Fairy
Shrimp, Contra Costa Goldfields, Northwestern Pond
Turtle, San Francisco Forktail Damselfly, Vernal
Pool Tadpole Shrimp.
004, 005, 007C,
016,029,030,031,
032, 033, 034, 036,
037
Title 16 USC
(Fish and Wildlife
Coordination Act)
662
Applicable
Regulates site actions affecting fish or
wildlife in lakes, stream, or other
water bodies by requiring
coordination between lead agency and
the U.S. Fish and Wildlife Service,
Department of the Interior, and
applicable state agencies.
Applicable to active groundwater remediation actions
and effluent discharges at sites which are located at or
near, or which may impact, Union Creek and pond.
004,005,016,029,
030, 033, 036, 037
3
Title 16 USC
(Migratory Bird
Treaty Act)
703
Applicable
Prohibits unlawful taking, possession,
and sale of almost all species of
native birds in the United States.
Species at Travis AFB include Black-Shouldered
Kite, Burrowing Owl, Coopers Hawk, California
Gull, Golden Eagle, Loggerhead Shrike, Northern
Harrier, Tri-colored Blackbird, Contra Costa
Goldfields.
004, 005, 007C,
016,029,030,031,
032, 033, 034, 036,
037
3
R
o
-------
i
CD
3
CL
70
O
D
Table 6-5
Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations
(continued)
Source
Requirement.
Standard, or
Criterion
Type
Description
Remarks
Sites and Alternatives
Federal Clean
Water Act,
Section 404, Title
33CFR
Part 330, Appx A,
Subpart B
Army Corps of
Engineers
Nationwide
Permit Programs
(NWP)
Paragraph 12
Paragraph 13
Paragraph 27
Applicable
Applicable
Applicable
Establishes Nationwide Permit for discharges
material for backfill or bedding of utility lines,
including outfall and intake structures affecting the
waters of the United States.
Establishes Nationwide Permit for bank
stabilization activities necessary for erosion
prevention.
Establishes requirements for activities in waters of
the United States associated with the restoration of
altered and degraded non-tidal wetlands and
creation of wetlands on private lands.
The substantive portions of these
paragraphs are applicable to activities
related to construction and installation
of remedial equipment. The permitting
requirements are not ARARs.
004,005,016,
029, 030, 033,
034, 036, 037
3
The substantive portions of these
paragraphs are applicable to activities
related to construction and installation
of remedial equipment. The permitting
and notification requirements are not
ARARs.
B
o
**»
UJ
5?
s
I
$
Federal Clean
Water Act,
Section 404,
Title 3 3 CFR Part
330, Appx A,
Subpart C
Army Corps of
Engineers
Nationwide
Permit Conditions
(NWP)
Paragraph 2
Paragraph 4
Paragraph 5
Paragraph 11
Applicable
Applicable
Applicable
Applicable
Requires any structure or fill authorized be
properly maintained, including maintenance to
ensure public safety.
Requires that no activity may substantially disrupt
the movement of those species of aquatic life
indigenous to the water body.
Requires heavy equipment working in wetlands
must be placed on mats or other measures be taken
to minimize soil disturbance.
No activity is authorized under any NWP if likely
to jeopardize the continued existence of a
threatened or endangered species or species
proposed for such designation, as identified under
the Federal Endangered Species Act, or which is
likely to destroy or adversely modify the critical
habitat of such species.
004, 005, 006,
007,015,016,
029,030,031,
032,033,034,
035,036,037
-------
i
-
3
o.
o
o
Table 6-5
Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations
(continued)
Source
Requirement,
Standard, or
Criterion
Type
Description
Remarks
Sites and Alternatives
Title 40 CFR Part
122
(Federal Clean
Water Act - EPA
Administered
Programs)
The National
Pollutant Discharge
Elimination System
122.26
I22.4l(d)
122.41(e)
I22.41(j)
(1)(3)&(4)
122.41
(0(6)
122.4 l(m)
122.41(n)
122.44(d)
122.44(g)
122.44(i)
I22.45(c)
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Requirements to ensure stormwater discharges
from remedial activities do not contribute to a
violation of surface water quality standards.
Requires all reasonable steps be taken to minimize
or prevent discharges which have a reasonable
likelihood of causing adverse impacts on surface
water quality.
Requires proper operation and maintenance of
treatment and control systems/equipment.
Establishes requirements for monitoring and
recordation of monitoring results.
Establishes informational requirements for any
noncompliance which may endanger health or the
environment.
Establishes prohibitions, limitations, and
restriction on treatment plant bypass.
Defines and establishes parameter for upset
conditions in a treatment plant.
Requires that discharges to surface water must
achieve federal and state water quality standards.
Identifies certain toxic pollutants as hazardous
substances.
Establishes monitoring requirements to assure
compliance with permit limitations and
requirements to monitor.
Establishes techniques and methodologies for
monitoring effluent levels of metals.
Applicable at all sites where there will be
discharge to the stormwater system and to
discharges to Union Creek. These
sections relate to effluent limitations and
monitoring requirements to be applied
during the development of a monitoring
plan.
Incorporates requirements of General
Order 94-087, paragraph F.6 (100-year
frequency flood).
The SRWQCB is authorized to
implement the NPDES program in the
State of California. (See California
Regional Water Quality Control Board,
San Francisco Bay Region Order 94-087
for substantive discharge standards.) Only
substantive portions of Part 1 22 are
ARARs; reporting requirements are
procedural.
Incorporates substantive requirements of
Order 94-087, Self Monitoring
Requirements, paragraphs D through H.
004, 005, 007C,
016,030,031,
032, 033, 034,
036, 037
3
K)
R
o
-*»
Ul
5?
8
I
-------
Table 6-5
Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations
(continued)
§
o
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
Title 40 CFR Part
!22(Cont.)
122.45(d)
122.45(e)
122.45(0
122.45(g)
122.48(a)
122.48(b)
Applicable
Applicable
Applicable
Applicable
Applicable
Applicable
Establishes format for reporting effluent limitation
standards and prohibitions.
Establishes format and limit criteria for
non-continuous discharge.
Establishes requirements and exceptions for
pollutants expressed in terms of mass.
Establishes credits for pollutants in the
dischargers intake water.
Establishes requirements for proper use,
maintenance, and installation of monitoring
equipment or methods.
Establishes requirements for monitoring including
type, intervals, and frequency sufficient to yield
data which are representative of the monitored
activity including, when appropriate, continuous
monitoring.
(Cont.)
004, 005, 007C,
016,030,031,
032, 033, 034,
036
3
5?
8
I
-------
I
Table 6-5
Federal ARARs - Groundwater Remediation (IROD)
Requirements under the US Code and Related Regulations
(continued)
Source
Requirement,
Standard, or
Criterion Type
Description
Remarks
Sites and Alternatives
40 USC Section
300, et seq.
(National Primary
Drinking Water
Standards) Title
40 CFR Part 141
141.11
141.12
141.61
141.62
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Establishes the federal allowable maximum
contaminant levels (MCLs) for arsenic in
community water systems and nitrates in
non-community water systems.
Establishes federal MCLs for trihalomethanes.
Establishes MCLs for organic contaminants.
Requires the best technology, treatment technique,
or other means available for achieving compliance
with MCLs.
Establishes MCLs for inorganic contaminants.
Requires the best technology, treatment technique,
or other means available for achieving compliance
with MCLs for identified contaminants, except
fluoride.
Relevant and appropriate to sites where
discharge of treated groundwater to
potential sources of drinking water will
occur. Establishes effluent treatment
standards for certain constituents which
are not addressed by the substantive
requirements of California Regional
Water Quality Control Board, SF Bay
Region, Order Number 94-087.
004, 005,
007C.OI6,
030,031,032,
033, 034, 036,
037
3
5?
s
-------
Table 6-6
NPDES Effluent Limitations for Treated Groundwater
Constituent
Instantaneous Maximum
(ug/J)
30-Day Median1
(ug/1)
Halogenated Volatile Organ ics
Bromodichloromethane
Carbon Tetrachloride
Chlorobenzene
Chloroform
Chloromethane
Dibromochloromethane
1 ,4-Dichlorobenzene
1 ,2-Dichloroethane
1 , 1 -Dichloroethylene
cis- 1,2-DichIoroethylene
trans- 1 ,2-Dichloroethylene
1 ,2-Dichloropropane
Ethylene Dibromide
Tetrachloroethylene (PCE)
Trichloroethylene (TCE)
Vinyl Chloride
100.02
0.52
70.02
100.02
100.02
5.02
0.52
6.02
6.02
10.02
5.02
0.052
5.02
5.02
0.52
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
Total Halogenated Volatile Organic;
1.0
Non-Halogenated Volatile Organics
Benzene
Ethylbenzene
Toluene
Xylenes
TPH - Gasoline
l.O2
29.03
42.03
17.03
50.04
0.5
0.5
0.5
0.5
50.0*
Semi- Volatile Organics
Aldrin
Alpha-BHC
Beta-BHC
Gamma-BHC (Lindane)
Bis(2-ethylhexy))phthalate
TBDS
TBD5
TBD$
TBDJ
TBD5
TBD5
TBD5
TBD5
TBD5
TBD5
Travis AFB Groundwater IROD
145
as of 3 December 1997
-------
Table 6-6
(Continued)
Constituent
Chlordane
4,4'DDT
4,4'DDD
Dieldhn
Dioxins
Endosulfan
Heptachlor epoxide
PCBs (Arochlors)
Total Polynuclear Aromatics (PAHs)
TPH - Diesel
Instantaneous Maximum
(ug/0
TBD5
TBD5
TBD5
TBD5
TBDJ
TBD5
TBD5
TBD5
TBD5
100.03
30-Day Median1
(ug/l)
TBD5
TBD5
TBD5
TBD5
TBD5
TBD5
TBD5
TBD5
TBD5
50.04
Inorganics6
Arsenic
Cadmium
Chromium VI
Total Chromium
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
190'
1.1
11.0'
11.0
12.0
3.2
0.0128
160.0
5.0
4.1
110.0
190 9
1.1
11. 07
11.0
12.0
3.2
0.0128
160.0
5.0
4.1
110.0
Best Available Technology for Volatile Organics.
California Primary MCL.
Taste and odor threshold in water - USEPA.
Practical Quantitation Limit.
To Be Determined: The Air Force agrees to sample for these constituents prior to discharge of effluent. When one or more of these
constituents are found, the parties will agree on instantaneous maximum and 30-day median effluent limitations. These constituents
(even if not detected initially) will be included in the monitoring program.
Both instantaneous maximum and monthly median limitations are based on USEPA Freshwater Ambient Water Quality Criteria for
Protection of Aquatic Life, expressed as total recoverable metal.
Compliance with the Chromium VI limitation may be met as Total Chromium.
Compliance is achieved by meeting the Reporting Limit using EPA Method 7470/7471. The effluent shall not contain more than
I gram/day of mercury.
Discharge limitation of 10ug/l for arsenic still applies to SS016.
Travis AFB Groundwater IROD
146
as of 3 December 1997
-------
Table 6-7
Discharge Limitations
1. The discharge of waste shall not cause the following conditions to exist in the waters of the
State at any place:
a) floating, suspended, or deposited macroscopic particulate matter or foam;
b) bottom deposits or aquatic growths;
c) alteration of temperature, turbidity, or apparent color beyond present natural background
levels;
d) visible, floating, suspended, or deposited oil or other products of petroleum origin;
e) toxic or deleterious substances to be present in concentrations or quantities which will
cause deleterious effects on aquatic biota, wildlife, or waterfowl, or which render any of
these unfit for human consumption either at levels created in the receiving waters or as a
result of biological concentration.
2. The discharge of waste shall not cause excursions of the following limits in waters of the
State in any place within one foot of the water surface:
a) Dissolved oxygen;
For all tidal waters, upstream of Carquinez Bridge, 7.0 mg/1 minimum; downstream
of Carquinez Bridge, 5.0 mg/1 minimum.
For nontidal waters, waters designated as cold water habitat, 7.0 mg/1 minimum;
waters designated as warm water habitat, 5.0 mg/1 minimum.
The median dissolved oxygen concentration for any three consecutive months shall
not be less than 80% of the dissolved oxygen content at saturation.
b) pH: The pH shall not be depressed below 6.5 nor raised above 8.5, nor caused to vary
from normal ambient pH levels by more than 0.5 units.
3. The discharge shall not cause a violation of any applicable water quality standard for
receiving waters adopted by the Board or the State Water Resources Control Board as
required by the Federal Clean Water Act and regulations adopted thereunder.
Source: California Regional Water Quality Control Board. San Francisco Bay Region, Order No. 94-087
Travis AFB Groundwater IROD 147 as of 3 December 1997
-------
Table 6-8
Effluent Treatment Levels for Beneficial Reuse
Discharges to Land for Irrigation Purposes
Water reclaimed for beneficial use shall meet the following limits:
Constituent
Volatile Organic Compounds
Vinyl Chloride
Benzene
Dichloroethane
All Others, Per Constituent
Instantaneous Maximum
Limit (ug/L)
0.5
0.5
0.5
5.0
Semi-Volatile Organic Compounds
Per Constituent
5.0
Total Petroleum Hydrocarbons
50
The following limitations shall apply:
1. Water reclamation activities shall be limited to irrigation.
2. No reclaimed water shall be allowed to escape from the authorized use area by airborne, nor by surface flow except in minor amounts
associated with good irrigation practice, nor from conveyance facilities.
3. Reclamation involving irrigation shall not occur when the ground is saturated.
4. The use of reclaimed water shall not impair the quality of waters of the State, nor shall it create a nuisance as defined by Section
13050(m) of the California Water Code.
5. Adequate measures shall be taken to minimize public contact with reclaimed water and to prevent the breeding of flies, mosquitoes, and
other vectors of public health significance during the process of reuse.
6. Appropriate public warnings must be posted to advise the public that the water is not suitable for drinking. Signs must be posted in the
area, and all reclaimed water valves and outlets labeled, as appropriate.
7. There shall be no cross-connection between the potable water supply and piping containing treated groundwater intended for reuse.
Source: California Regional Water Quality Control Board, San Francisco Bay Region. Order No. 94-087
Travis AfB Groundwater IROD
148
as of 3 December 1997
-------
7.0 REFERENCES
BioSystems Analysis, Inc., 1992. Assessment of Special Status Animal and Plant Species at Travis
AFB, California, BioSystems Analysis, Inc. Tiburon, CA.
BioSystems Analysis, Inc., 1993. Assessment of Special Status Plant and Animal Species at Travis
AFB, Solano County, California: Phase II Surveys. BioSystems Analysis, Inc. Tiburon, CA.
California Division of Mines and Geology, 1981. Sacramento Quadrangle Map No. 1A. 1981.
CH2M HILL, 1996. Tier Two Ecological Risk Assessment. March 1996. ;
Cherry, 1996. Conceptual Models for Chlorinated Solvent Plumes and their Relevance to
Intrinsic Remediation, in Symposium on Natural Attenuation of Chlorinated Organics in
Groundwater, EPA/540/R-96/509, pages 29-30, September 1996.
Earth Technology, 1994. Installation Restoration Program (IRP) Engineering Evaluation and
Cost Analysis (EECA) and Environmental Assessment in Support of a JP4 Non-Time-Critical
Removal Action - IRP Site SSOJ West Industrial Operable Unit. March.
Freeze and Cherry, 1979. Groundwater. R. Allan Freeze and John A. Cherry. Prentice-Hall, Inc.
1979.
Marchard, D.E., and Allwardt, A., 1977. Late Cenozoic Stratigraphic Units of the Northeastern
SanJoaquin Valley. USGS Open File Report 77-748, 136p.
Olmsted and Davis, 1961. Geologic Features and Groundwater Storage Capacity of the
Sacramento Valley, California. United States Geological Survey Water Supply Paper 1497, 241 p.
Parsons Engineering Science, Inc., 1996. Installation Restoration Program Management Action
Plan, Travis AFB. January 1996.
Radian, 1994. Tower Area Removal Action Environmental Evaluation/Cost Analysis.
2 September.
Radian 1995a. Tower Area Removal Action National Pollution Discharge Elimination System
Self Monitoring Quarterly Report, Travis AFB, California, 1995.
Radian 1995b. North Industrial Operable Unit Remedial Investigation, Travis AFB. Final.
July 1995.
Travis AFB Groundwater IROD 149 as of 3 December 1997
-------
Radian, 1995c. Addendum to the NOUR1 Report. 2 November 1995.
Radian, 1995d. Treated Groundwater Use Plan, Travis AFB. Final. September 1995.
Radian 1996a. North/East/West Industrial Operable Unit Feasibility Study, Travis AFB. Final.
September 1996.
Radian 1996b. West Industrial Operable Unit Remedial Investigation, Travis AFB. Final.
February 1996.
Radian, 1996c. Travis AFB Announces Plan for Interim Cleanup of Contaminated Groundwater
in NEWIOU (Travis AFB Ground\vater Proposed Plan). September 1996.
Radian, 1996d. Tower Area Removal Action Environmental Evaluation/Cost Analysis,
Explanation of Significant Differences.
Thomasson, H.G., F.H. Olmsted, and E.F. LeRouz, 1960. "Geology, Water Resources, and Useable
Groundwater Storage Capacity of Part of Solano County, California." USGS Water Supply. Paper
1464,693p.
U.S. Air Force, 1993. RACER/ENVEST™. Remedial Action Cost Engineering and
Requirements System. Environmental Cost Engineering. Technical Contact: Dr. Rita A. Gregory.
AFCESA/DC. Tyndall AFB, Florida. 10 May 1993.
U.S. EPA, 1992. Time Critical Removal Action. 15 December.
U.S. EPA, 1996. Final Guidance: Presumptive Response Strategy and Ex-Situ Treatment
Technologies for Contaminated Ground Water at CERCLA Sites. Office of Solid Waste and
Emergency Response, U.S. Environmental Protection Agency, Washington, D.C. October 1996.
Wagner, 1982. Geologic Map of the Santa Clara Quadrangle. California Division of Mines and
Geology.
Weston, 1990. Stage 2 Draft Technical Report Travis AFB. January 1990.
Weston, 1992. Technical Information Report. Conceptual Site Models, Travis AFB, California.
Volumes I and II.
Weston, 1995a. East Industrial Operable Unit Remedial Investigation, Travis AFB. Final.
October 1995.
Weston, 1995b. Base-wide Ecological Habitat Survey. Draft. June 1995.
Travis AFB Ground water IROD 150 as of 3 December 1997
-------
Wiedemeier, T. H., Wilson, J.T., Kampbell, D.H., Miller, R.N., and Hansen, J.E., 1995.
Technical Protocol for Implementing Intrinsic Remediation with Long-Term Monitoring for
Natural Attenuation of Fuel Contamination Dissolved in Groundwater, San Antonio TX, U.S.
Air Force Center for Environmental Excellence.
Wiedemeier, T. H., Swanson, M.A., Moutoux, D.E., and Gordon, E. Kinzie, Wilson, J.T.,
Wilson, B.H., Kampbell, D.H., Hansen, I.E., Haas, P., and Chapelle, F.H., 1996. Technical
Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater, San
Antonio TX, U.S. Air Force Center for Environmental Excellence. November 1996.
Travis AFB Croundwater IROD 151 as of 3 December 1997
-------
PART III: RESPONSIVENESS SUMMARY
The primary avenues of public input have been through the Proposed Plan and public
comment period. The Proposed Plan for groundwater was issued to the public on 25 September
1996. To encourage public comment, the U.S. Air Force (USAF) held a public meeting on
17 October 1996, distributed Proposed Plans to libraries in the area, and included the phone
numbers and e-mail addresses of USAF and agency representatives.
The public meeting to receive comments on the Proposed Plan was attended by various
community members. Oral comments were received from one person: Bill Petersen. Following
the public meeting, and prior to the conclusion of the public comment period, written comments
were submitted by one individual: Carl Freitas of Oakland, California.
All comments received are documented in the administrative record file for the site.
A transcript of the public meeting is available for public review at the site information repository.
The repository is located off-base at the Vacaville Public Library, 1020 Ulatis Drive. Public
comments, relevant to contaminated groundwater in the NEWIOU and/or the environmental
restoration program at Travis AFB, are presented below and have been paraphrased for greater
clarity. This IROD is based on the documents in the Administrative Record and comments
received from the public.
Public Comment la: There was a concern that contaminants on base could impact
neighboring property by contaminants migrating off base or by discharge of treated water
to storm drains and creeks.
USAF Response: The USAF has identified three areas where contamination has
migrated off-base: two on the south base boundary and one on the North. At these sites, the
USAF proposes putting in wells to clean the contaminated off-base groundwater to drinking
Travis AFB Groundwater IROD 152 as of 3 December 1997
-------
water standards and prevent any future migration of contaminated ground water off-base. The
primary contaminant in the off-base groundwater is Trichloroethene (TCE) which is a solvent
used at Travis until 1980. At the other sites (where all contamination is on-base), the proposed
cleanup actions and monitoring will minimize the migration of contaminated groundwater and
ensure there will not be any additional off-base migration.
Areas of past fuel spills at the base have been investigated and have resulted in some
contamination of on-base groundwater but no contamination of off-base groundwater. One fuel
spill in 1978 did temporarily contaminate off-base surface water (Union Creek), but due to
removal and dissipation did not have any long term effect to either surface water or groundwater.
Water that is treated and discharged to storm sewers or Union Creek will meet stringent
clean water standards (drinking water levels) set by the State of California Regional Water
Quality Control Board. The Board will oversee the operation of all treatment plants and verify
compliance with the discharge standards.
Public Comment Ib: Additional information was requested on the location of the
groundwater contamination south of the base relative to the location of off-base wells and
roads.
USAF Response: There are two plumes of contaminated groundwater that have
migrated beyond the southern base boundary. The groundwater flow in this area is to the South.
The plumes are referred to as site SS030 and FT005 (see figure 5 of the Proposed Plan). The
most recent data indicate the southernmost edge of the SS030 plume is approximately 1000 feet
north of Creed Road, 1000 feet north-northeast of the nearest production well, and 1300 feet
north-northwest of the nearest Travis AFB monitoring well pair on Creed Road. The
southernmost edge of the FT005 plume is approximately 2000 feet north of creed road, 1/2 mile
west-northwest of the nearest production well, and 1/2 mile north-northwest of the nearest Travis
AFB monitoring well pair on Creed Road.
Travis AFB Groundwaler 1ROD 153 as of 3 December 1997
-------
Public Comment Ic: There was a concern that removal of contaminated
groundwater would reduce the supply of water on neighboring property.
USAF Response: Pumping will be designed to extract only contaminated groundwater
and to minimize the amount of groundwater requiring treatment. The groundwater action is
intended to remove only the quantity of water that will achieve capture of the contaminated
plume. Based on modeling of the groundwater south of the base, the operation of extraction wells
associated with remediation of the off-base plumes would have a minor effect (less than a 3 foot
decrease in average water level) on a well 1,000 feet from the remedial extraction wells, a
minimal effect (less than a 5 inch decrease in average water level) on a well 1 mile from the
extraction wells, and no discernible effect (less than 1 inch decrease in average water level) on
wells 1.25 miles or more from the extraction wells. During operation of the extraction wells, the
effects on water levels will be monitored and evaluated to ensure there is not a significant impact
on the off-base groundwater supply.
Public Comment 2a: The Proposed Plan is based on very limited testing of soil
and/or groundwater on the Freitas property (the only testing we are aware of was
5 hydropunch samples taken in one limited area in July, 1995). Is the need for any further
testing anticipated? If so, what type of testing and when should it take place? Given the
limited testing done, with what degree of confidence has the level of contamination and the
extent of the contaminated groundwater plume been established?
USAF Response: The results of on-base soil, sediment, surface water, and groundwater
sampling for landfill No. 2 (also known as site LF007) were presented in the North Operable
Unit (NOU) Remedial Investigation (RI) Report of July 1995. The report concluded that the
contamination and the contamination sources were all on-base except trichloroethene (TCE)
groundwater contamination near the northern boundary of the landfill. In order to investigate the
level and extent of the off-base groundwater contamination, the five groundwater samples
(hydropunch) were taken on the Freitas property. The results of this groundwater sampling are
Travis AFB Groundwater IROD 154 as of 3 December 1997
-------
documented in the NOU RI Report Addendum of October, 1995 and showed one off-base
detection of TCE (31 ng/L) surrounded by four locations (east, north-northeast, north-northwest
and west) with no detection of TCE. Based on that information, Travis AFB considers the plume
to be adequately defined for planning and selection of interim remedial actions. Additional
sampling may be needed for specific engineering design purposes. Samples may also be
collected at some time in the future (probably several years from now) to confirm that the interim
remedial goal has been attained and that the groundwater concentrations meet drinking water
standards.
Public Comment 2b: The Proposed Plan does not define a time line for the cleanup
process. What level of hazard is presently associated with the Freitas property? What
reduction in the level of contamination is targeted, and over what time frame? What are
restrictions (as a practical matter) on use of the Freitas property while the cleanup process
is taking place?
USAF Response: Our current estimate is that it could take 12 years to reduce the TCE
concentration in the off-base plume from 31 ug/L to the drinking water standard of 5 ng/L. There
is no current level of hazard (human health risk) from the groundwater contamination because
the water is not being used. The groundwater contamination will not affect surface land uses
(such as ranching or agriculture). Prior to cleanup, a production well (for household or livestock
consumption) should not be installed in the area where the five off-base samples were taken.
Also, during any soil excavations that would reach the groundwater in this area, minor
precautions should be taken to limit worker exposure to the contaminated groundwater.
Public Comment 2c: Since the source of contamination on the Freitas property is
apparently, at least in part, Landfill 2, and since the plan anticipates only natural
attenuation and monitoring of Landfill 2, what is the likelihood of further contamination
emanating from Landfill 2 and further contaminating the Freitas property?
Travis AFB Groundwater IROD 155 as of 3 December 1997
-------
USAF Response: At Landfill 2 (LF007), wells will be installed to pump and treat the
off-base plume to reduce the contamination level to MCLs and to prevent future off-base
migration of contaminated ground water. The remaining portions of Landfill 2 will use natural
attenuation as an interim action. This is considered a reasonable approach since the contaminant
levels are low and the plume has exhibited limited migration thus far. In addition, although the
area in question has groundwater migration to the north, this is a localized anomaly and the
overall direction of groundwater migration is generally toward the south. The installation of the
extraction well is expected to stop the northward migration and allow the regional southerly
migration to dominate.
The results of this approach will be periodically monitored and reviewed by the
regulatory agencies, and more aggressive action will be implemented if it appears there is any
potential for future migration onto the Freitas property. Also, the anticipated remedial action for
the soil at Landfill 2 (capping) will reduce the infiltration of rainwater into the landfill and will
route drainage away from the landfill areas. This action will reduce the groundwater flow
potential and the movement of contaminants and will also reduce the localized flow direction to
the north.
Travis AFB Groundwater IROD 156 as of 3 December 1997
-------
APPENDIX A
SITE-SPECIFIC SUMMARIES
-------
TABLE OF CONTENTS
Page
APPENDIX A: SITE-SPECIFIC SUMMARIES A-l
A.I SITE FT004 (FIRE TRAINING AREA 3) A-4
A.I.I Site Background A-4
A.1.2 Feasibility Study A-5
A.I.3 Selected Interim Remedial Actions/Objectives A-5
A. 1.4 Conceptual Site Model A-5
A.2 SITE FT005 (FIRE TRAINING AREA 4) A-8
A.2.1 Site Background A-8
A.2.2 Feasibility Study A-9
A.2.3 Selected Interim Remedial Actions/Objectives A-9
A.2.4 Conceptual Site Model A-10
A.3 SITE LF006 (LANDFILL 1) A-12
A.3.1 Site Background A-12
A.3.2 Feasibility Study A-13
A.3.3 Selected Interim Remedial Actions/Objectives A-13
A.3.4 Conceptual Site Model A-14
A.4 SITE LF007 (LANDFILL 2, AREAS B, C, AND D) A-l6
A.4.1 Site Background A-16
A.4.2 Feasibility Study A-17
A.4.3 Selected Interim Remedial Actions/Objectives A-18
A.4.4 Conceptual Site Model A-19
A.4.5 Special Site Conditions A-19
A.5 SITE SSO15 (SOLVENT SPILL AREA AND FACILITIES 550
AND 552) A-23
A.5.1 Site Background A-23
A.5.2 Feasibility Study A-24
A.5.3 Selected Interim Remedial Actions/Objectives A-25
A.5.4 Conceptual Site Model A-26
A.6 SITE SSO 16 (OIL SPILL AREA, FACILITIES 11, 13/14, 18, 20,
42/1941, 139/144, AND SELECTED SECTIONS OF STORM
SEWER RIGHT OF WAY) A-28
A.6.1 Site Background A-28
A.6.2 Feasibility Study A-32
A.6.3 Selected Interim Remedial Actions/Objectives A-32
A.6.4 Conceptual Site Model A-33
-------
TABLE OF CONTENTS (Continued)
Page
A.7 SITE SS029 (MW-329 AREA) A-35
A.7.1 Site Background A-35
A.7.2 Feasibility Study A-36
A.7.3 Selected Interim Remedial Actions/Objectives A-36
A.7.4 Conceptual Site Model A-37
A.8 SITE SS030 (MW-269 AREA) A-39
A.8.1 Site Background A-39
A.8.2 Feasibility Study A-40
A.8.3 Selected Interim Remedial Actions/Objectives A-40
A.8.4 Conceptual Site Model A-41
A.9 SITE SD031 (FACILITY 1205) A-43
A.9.1 Site Background A-43
A.9.2 Feasibility Study A-44
A.9.3 Selected Interim Remedial Actions/Objectives A-44
A.9.4 Conceptual Site Model A-45
A.10 SITE ST032 (AREAS OF MW-107 AND MW-246) A-47
A.10.1 Site Background A-47
A.10.2 Feasibility Study A-48
A. 10.3 Selected Interim Remedial Actions/Objectives A-48
A.10.4 Conceptual Site Model A-49
A. 11 SITE SD033 (STORM SEWER SYSTEM II/FACILITIES 810
AND 1917, SOUTH GATE AREA, AND WEST BRANCH OF
UNION CREEK) A-51
A.I 1.1 Site Background A-51
A.I 1.2 Feasibility Study A-52
A. 11.3 Selected Interim Remedial Actions/Objectives A-53
A.I 1.4 Conceptual Site Model A-54
A.12 SITE SD034 (FACILITY 811) A-56
A. 12.1 Site Background A-56
A.12.2 Feasibility Study A-57
A.I2.3 Selected Interim Remedial Actions/Objectives A-57
A.12.4 Conceptual Site Model A-58
A.12.5 Special Site Considerations A-58
A.13 SITE SS035 (FACILITIES 818/819) A-60
A. 13.1 Site Background A-60
A.13.2 Feasibility Study A-60
A. 13.3 Selected Interim Remedial Actions/Objectives A-61
A.13.4 Conceptual Site Model A-62
-------
TABLE OF CONTENTS (Continued)
Page
e>
A.14 SITE SD036 (FACILITIES 872/873/876) A-64
A.14.1 Site Background A-64
A.14.2 Feasibility Study A-65
A.14.3 Selected Interim Remedial Actions/Objectives A-65
A.14.4 Conceptual Site Model A-65
A.14.5 Special Site Considerations A-66
A. 15 SITE SD037 (SANITARY SEWER SYSTEM, FACILITIES 837,
838, 919, 977, AND 981, AREA G RAMP, AND
RAGSDALE/V AREA) A-68
A.15.1 Site Background A-68
A.15.2 Feasibility Study A-70
A. 15.3 Selected Interim Remedial Actions/Objectives A-71
A.15.4 Conceptual Site Model A-72
A.15.5 Special Site Considerations A-72
-------
LIST OF FIGURES
Page
A-l Site Summary Information for FT004, Travis AFB A-7
A-2 Site Summary Information for FT005, Travis AFB , A-l 1
A-3 Site Summary Information for LF006, Travis AFB A-15
A-4 Site Summary Information for LF007, Area B, Travis AFB A-20
A-5 Site Summary Information forLFOO?, AreaC, Travis AFB A-21
A-6 Site Summary Information for LF007, Area D, Travis AFB A-22
A-7 Site Summary Information for SS015, Travis AFB A-27
A-8 Site Summary Information for SS016, Travis AFB A-34
A-9 Site Summary Information for SS029, Travis AFB A-38
A-10 Site Summary Information for SS030, Travis AFB A-42
A-l 1 Site Summary Information for SD031, Travis AFB A-46
A-12 Site Summary Information for ST032, Travis AFB A-50
A-13 Site Summary Information for SD033, Travis AFB A-55
A-14 Site Summary Information for SD034, Travis AFB A-59
A-15 Site Summary Information for SS035, Travis AFB A-63
A-16 Site Summary Information for SD036, Travis AFB A-67
A-l7 Site Summary Information for SD037, Travis AFB A-73
-------
APPENDIX A
SITE-SPECIFIC SUMMARIES
Appendix A includes site-specific information for each groundwater site within the
North, East, and West Industrial Operable Unit (NEWIOU). The site-specific information is
presented as text as well as on a composite figure showing the general conceptual site model, the
extent of groundwater contamination, and the conceptual layout for the extraction strategy. These
site-specific summaries include background and contaminant information from the individual
Operable Unit (OU) Remedial Investigation (RI) reports, a brief description of the Feasibility
Study (FS) evaluation, including specific costs, and a description of the selected interim remedial
actions and objectives.
A detailed description of the alternatives developed in the FS is included in Section 4.0
of this Interim Record of Decision (IROD). The Air Force developed the FS alternatives, as
described in Section 3.0 of the NEWIOU FS, to meet the Remedial Action Objectives (RAOs) to
compare alternatives based on cleanup of the contaminated groundwater to drinking water
standards. The Air Force evaluated the alternatives with a scoring system developed in the FS.
Each interim remedial action was scored on the basis of seven Comprehensive Environmental
Response Compensation and Liability Act (CERCLA) criteria (see Figure 4-1 and Table 4-4).
Scores for each action are discussed in the site summaries.
Additionally, the Air Force estimated costs in the FS for the extraction, treatment, and
discharge alternatives and these costs are presented for each site in this appendix. (The
Alternative numbers 3 through 9 in this section are the numbers used in the FS for the treatment
alternatives. These alternatives have been combined into Alternative 3 [Extraction, Treatment,
and Discharge] in the Groundwater IROD.) The interim remedial actions selected for the
Groundwater IROD are the most cost-effective approach; the cost for the interim action may
differ from the costs developed for the comparison of alternatives in the FS. However, these
costs are included to allow comparison of alternatives. Final costs for each site will be developed
Travis AFB Groundwater IROD A-1 as of 3 December 1997
-------
during the design phase, and will reflect the groundwater extraction strategy and the combining
of extracted water from different sites for treatment at one or more locations.
Also, the Air Force will finalize the layout and design of the extraction wells (vertical
or horizontal) during the design phase; the layout of extraction wells presented on the site-
specific figures is conceptual. The Air Force will specify monitoring wells for all groundwater
sites during the design phase and may include existing or new locations. The Air Force will use
these wells to collect data at all sites for natural attenuation. The aerial extent of contamination is
indicated on the site-specific figures, and an estimated volume of contaminated grouridwater is
included for general comparisons. The Air Force will use data obtained during the remedial
design/remedial action (RD/RA) phase and analysis of site-specific data to optimize locations of
extraction and monitoring wells.
The Air Force will provide the monitoring data from all sites to the regulatory agencies
and the Restoration Advisory Board (RAB) for their review and comment. At sites where natural
attenuation is assessed, the Air Force will also provide each site's data summary and assessment
report for review and approval. A formal review at the end of the five-year interim period will
address the acceptability of natural attenuation as a final cleanup action. After this five-year
review, a Basewide Groundwater Proposed Plan will present the preferred final cleanup action
(natural attenuation, pump and treat, or other) for each site. This Proposed Plan will have a
minimum 30-day public comment period. Following the Proposed Plan, a final Groundwater
Record of Decision (ROD) will finalize the cleanup decision. The Air Force will submit the Draft
Final Groundwater ROD to the agencies and the RAB for review and comment. The regulator}'
agencies will review and approve the Draft Final Groundwater ROD.
Other chemicals that are not contaminants of concern (COCs) may also be identified in
the site summaries, either in the text or on the figures. Total petroleum hydrocarbons (TPH) are
not identified as COCs for any sites in the East Industrial OU (EIOU). Where TPH
concentrations are greater than 1,500 ug/L or where TPH may be a potential threat to ecological
Travis AFB Groundwater IROD A-2 as of 3 December 1997
-------
receptors, TPH concentrations are presented. In addition, at some sites throughout the NEWIOU,
metals, although not COCs, may affect discharge if concentrations are above National Pollution
Discharge Elimination System (NPDES) limits. In such cases, the metals that may need
treatment are identified. The need for metals treatment to meet NPDES limits will be determined
during the RD/RA.
These site-specific summaries present information developed during the CERCLA
process to support the selected interim action(s) for each site. This information will be useful in
guiding future design decisions, although each OU RI report includes a complete record of the
site contaminants that may affect future engineering considerations.
Travis AFB Groundwater IROD A-3 as of 3 December 1997
-------
A.1 SITE FT004 (FIRE TRAINING AREA 3)
A.I.I Site Background
Site FT004 covers approximately 30 acres in the north-eastern portion of the EIOU and
consists of the old Fire Training Area 3 (FTA-3). The site was used for fire training exercises
from 1953 to 1962 (Weston, 1995a). During these exercises waste fuel, oils, and solvents were
dumped onto frames or on the ground and burned. Some soil staining and stressed vegetation
was observed during recent investigations at the site, now an unused, open field.
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU Rl (Weston, 1995a). Summary tables
2.2-1 through 2.2.-3 and Appendix A of the RI indicate that groundwater samples were collected
from monitoring wells at FT004. The Air Force collected 28 groundwater samples in Rounds 7
through 9 and analyzed them for volatile organic compounds (VOCs), inorganic constituents,
semivolatile organic compounds (SVOCs), pesticides and polychlorinated biphenyls (PCBs), and
petroleum hydrocarbons. In addition, the Air Force collected subsurface samples from 7 soil
borings, 3 sediment samples, and 11 surface soil samples. Sampling locations, constituents
analyzed, and results can be obtained in the EIOU RI (Weston, 1995a).
COCs found in the groundwater during the RI conducted at the site are primarily
VOCs, with one SVOC and one metal also identified as a COC. VOCs include trichloroethene
(TCE), cis-l,2-dichloroethene (DCE), 1,2-dichloroethane (DCA), chloroform,
dichlorobromomethane, 1,1-DCE, vinyl chloride, and 1,4-dichlorobenzene. The SVOC identified
as a COC at FT004 is bis(2-ethylhexyl)phthalate, and the metal is nickel. Although not a COC,
TPH was identified at an average of 1,000 ng/L (maximum 7,700 ug/L). Site location,
contaminant concentrations, and a conceptual site model are shown on Figure A-l. Other
Travis AFB Groundwater IROD A-4 as of 3 December 1997
-------
contaminants found at the site include dioxins and metals (copper, antimony, cadmium, lead, and
zinc) in the soil.
A. 1.2 Feasibility Study
The alternatives evaluated in the FS for FT004 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, ultraviolet
oxidation [UV-OX], ion exchange, activated carbon, and discharge), and Alternative 7
(extraction, ion exchange, activated carbon, and discharge). As evaluated, Alternative 1 had the
lowest cost, but also the lowest total score. Alternative 2 has a capital cost of $18,600, first year
operation and maintenance (O&M) cost of $72,000, and a score of 16. Alternatives 3, 5, and 7
had similar scores ranging from 27 to 29. Costs were $915,000 capital with $280,000 O&M for
Alternative 3; $960,000 capital with $310,000 O&M for Alternative 5; and $3 million capital
with $3 million O&M for Alternative 7.
A. 1.3 Selected Interim Remedial Actions/Objectives
The selected interim action for groundwater at FT004 is Alternative 3, Extraction,
Treatment, and Discharge. The Air Force will accomplish this with source control for the TCE.
Source control has been selected for this site because the presence of dense non-aqueous phase
liquid (DNAPL) is suspected with TCE concentrations greater than 3,000 ug/L.
A. 1.4 Conceptual Site Model
Fire training exercises may have led to groundwater contamination at FT004 by
leaching from burned material. The groundwater COCs (VOCs, SVOC, and nickel), however,
were not identified as COCs in soil. Soil contamination was detected and COCs include dioxins
and metals. These contaminants in soil have low mobility and have not impacted groundwater
Travis AFB Groundwater IROD A-5 as of 3 December 1997
-------
(i.e., dioxins and the specific metals in soil are not COCs in the groundwater). Any anticipated
soil cleanup action is not expected to have an effect on groundwater because the COCs are not
the same. The source of the nickel in groundwater is not known and is currently being
investigated.
Travis AFB Groundwater IROD A-6 as of 3 December 1997
-------
Conceptual Model
Fir* Training Arf • 1
WaUrrTabla
Anuvtun
OroundwaUr Contamination
- ;-
-.;•';•'?'4^;- •."•'47 t**j><*:"'- '•'•
FT004 (Fire Training Area 3)
0 140 XXI MO
B—-"C
SCALE IN FEET
trwa AfD 6ram»M< WOO
NOTE S« »0|«c»nno FIOOJ
•mm ol KX conumnibon
FTOOJ
Madlum
Groundwatar
Grounowilar
GroundwHar
Groundwatar
Groundwatar
Groundwalat
Groundwalar
GVoundwllar
Grounowaiar
Groundwatar
[lln**i F'M1t*<"B1HMI D**v*fa and Aftaetod Uadla
Conlamlnanl
Tirpa
VOCl
VOCl
VOCl
VOCl
VOCl
VOCl
VOCl
VOCl
svoci
Maun
MtlMdlalion
Drivar
CoOactna
Human Rnk
torThaia
Conumnanu
•> ,
HR.1.GBHO''
Conlimlrwnl
olConearn
TCE
o» I.20CE
1.2-OCA
Crkxodxm
DieNorotxomomattiana
1.!^x:E
V«»l ChKmda
l.4f>cntorobaniana
bu(2-afttvlriaKyf)prttrtalata
NiCkol
Maiknum
fiaponad
Concantrillon
S.200,«n NPO£S da<»wo« !»««
In SOTTW irionitQnnQ c Ondahon, Ion Excnanga ActNatad Caibon
Capua) Coal - $913.000; F«l Yaa/ O » M - W60.000
• FS Anamaova S. UV Oudilran. km ExcXanga, Activalaa Cvtwri
CapnaJ Cent - 19*0,000; Fnl Yaaf 0 1 U - 1310.000
• FS Attamttnra 7: ton E«chang«. Aoj.alad Carbon
Capilal Coal - S3.000.000; F»U Yaw 0 ( M • S3.000.000
• Than cotu danvad Irom tha FS wtn ba radnad during lha lamadm datign phu*
batad on eomtiinitMn tt aAarrutMi and ail* apaaftc vamblM
• Ona horizontal««. 300 teal In acraanad langth
(NOTE: Localion and numow o« «raOi m* ba daurrranad dimng lamadul daaign phua)
• Extnaion ratal 5 gpm total
• 700 la« of untruiad waiar piping (Irom «•• 10 raatmart ayttam)-- I men IO. Kti to PVC
• 200 taatoldiaerwrof piping (to Dorm miKr) — < Inon O. Mfl M PVC
1 Figure A-l.
Site Summary In formal Ion
for FT004, Travis AFB
i irV*U-Va»>«>W
A-7 ataOlMOTM
MriMT
-------
A.2 SITE FT005 (FIRE TRAINING AREA 4)
A.2.1 Site Background
Site FT005 covers approximately 30 acres in the southeastern portion of the EIOU. The
site is the location of the old Fire Training Area 4 (FTA-4) and was used for fire training
exercises from 1962 through 1987, approximately. Historical aerial photographs indicate that the
area may have also been used for munitions storage prior to 1958 (Weston, 1995a). From 1962
until the early 1970s, waste fuels, oils, and solvents were burned at the site during training
exercises. From the early 1970s until FTA-4 was closed, only waste fuels were burned. An
aboveground storage tank was installed around 1976 to hold the waste fuels and is currently
located at the site. The site had no berms or dikes to contain runoff, and surface runoff may have
flowed into Union Creek during training exercises. During site visits some stressed vegetation
was observed in areas bordering the site and drainage swales (Weston, 1995a).
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RJ (Weston, 1995a). Summary tables
2.2-1 through 2.2.-3 and Appendix A of the RI indicate that groundwater samples were collected
from monitoring wells and from CPT locations at FT005 during Rounds 7 through 9. The Air
Force collected 78 groundwater samples and analyzed them for VOCs, SVOCs, PCBs,
pesticides, petroleum hydrocarbons, and inorganic constituents. In addition, the Air Force
collected subsurface soil samples from 7 soil borings, 16 surface soil samples, and 3 sediment
samples. Sampling locations, constituents analyzed, and results can be obtained in the EIOU RI
(Weston, 1995a).
COCs found in the groundwater during the RI are primarily VOCs, with one SVOC and
one metal also identified. VOCs include TCE, 1,2-DCA, cis-l,2-DCE, chloroform, and
Travis AFB Groundwalcr 1ROD A-8 as of 3 December 1997
-------
dichlorobromomethane. The SVOC identified as a COC is bis(2-ethylhexyl)phthalate, and the
metal is nickel. Site location, contaminant concentrations, and a conceptual site model are
presented in Figure A-2. Contaminants detected in soils at the site include polynuclear aromatic
hydrocarbons (PAHs), PCBs, dioxins, pesticides, and metals (chromium, copper, lead, cadmium,
nickel, selenium, and zinc) in the surface and subsurface soils.
A.2.2 Feasibility Study
The alternatives evaluated in the FS for FT005 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had similar scores ranging from 29 to 31.
Costs were $1.8 million capital with $260,000 O&M for Alternative 3; $1.85 million capital with
$295,000 O&M for Alternative 5; and $1.7 million capital with $360,000 O&M for
Alternative 7.
A.2.3 Selected Interim Remedial Actions/Objectives
The selected interim action for groundwater at FT005 is Alternative 3, Extraction,
Treatment, and Discharge. The Air Force will accomplish this with a combination of off-base
remediation for 1,2-DCA and migration control to control movement of contaminated
groundwater.
Travis AFB Groundwater 1ROD A-9 as of 3 December 1997
-------
A.2.4 Conceptual Site Model
Fire training exercises may have led to groundwater contamination by leaching of the
solvents burned at FT005 but VOCs and fuels were not identified as COCs for soil. Surface soil
contamination includes PAHs, PCBs, pesticides, dioxins, and metals. These contaminants in soil
have not impacted groundwater, and any anticipated soil cleanup action is not expected to have
an effect on groundwater.
Nickel is an identified COC in both the groundwater and the soil. However, the source
of the nickel is not known and is currently being investigated. A portion of the groundwater
plume with 1,2-DCA has migrated off-base; TCE contamination has remained on-base.
Travis AFB Groundwater IROD A-l 0 as of 3 December 1997
-------
FT005 (Fire Training Area 4)
Primary Contaminants. Remediation Drivers apfl Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
Remediation
Driver
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
Metals
Collective
Human Risk
for These
Contaminants
Is
HR = 1.12x10~4
Contaminant
of Concern
TCE
1.2-DCA
cis-1.2-DCE
Chloroform
Dichlorobromomethane
bis(2-ethylhexyl)phthalate
Nickel
Maximum
Reported
Concentration
LB^g/L
35.9 ^g/L
370 mg/L
Site Characteristics
• Site is located in an area of Travis AFB that is inactive except for explosives detonation
• TCE in groundwater — 3.3 fig/L average, 120 f*g/L maximum
• Estimated contaminated groundwater surface area = 1,600,000 f£ volume = 12.000,000 ft3
• Estimated mass of dissolved VOCs equals 3.9 Ib; no evidence of DNAPL or LNAPL
• Cr, Cu, and Hg were measured at concentrations greater than NF'DES discharge limits
in some monitoring wells
• Depth to groundwater — 10 feet; depth to bedrock — 50 feet
• Permeable materials (sand and silt) occur through depths of 20 to 40 feet bgs
• Some low permeability soils (clay and silt) occur between 10 and 30 feet bgs
• Site also studied for surface soil contamination
• The bold dashed line indicates where the FT005 groundwater contamination overlaps the soil site WP017
Selected Interim Remedial Action/Objectives
Alternative 3: Extraction, Treatment and Discharge
- Off-base Remediation for 1,2-DCA
- Migration Control for TCE and 1,2-DCA
Feasibility Study Treatment Alternatives and Associated Costs
• Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $18.600; First YearO & M = $72,000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 3: Air Stripper/Catalytic Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $1,800,000; First Year O & M = $260,000
- FS Alternative 5: UV Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $1,850,000; First Year O & M = $295.000
- FS Alternative 7: Ion Exchange, Activated Carbon:
Capital Cost = $1,700,000; First Year O & M = $360.000
• These costs derived from FS will be refined during the remedial design phase
based on combination of alternatives and site specific variables
Interim Design Assumptions
• 4 horizontal wells, 300 feet in screened length
(NOTE: Location and number of wells will be determined during the remedial design phase)
• Extraction rate 60 gpm total, 15 gpm from each well
- 4,500 feet of untreated water piping (from well to treatment system) — 1 inch ID, sen 80 PVC
• 1,000 feet of discharge piping (to Union Creek) — 3 inch ID, sch 80 PVC
• 1,000 feet from treatment system to existing power line
Figure A-2.
Site Summary Information
for FT005, Travis AFB
A-ll
SFTOOS.COfl • VMG 8/19/97 SAC t
as of 3 December 1997
-------
Conceptual Model
Rre Training Exercises
Base Boundary
V Water Table_
Alluvium
(Clays, Silts, Sands)
1,2-DCE Extent
in Groundwater
Area of
Contaminated Soil
(Ecological Risk)
_ Extent
Groundwater
\ / x-,
< Treatment
System \
Base Boundary
Discharge Piping
1,2-DCA Extent
In Groundwater
Wells for
Migration
Control
Off-Base Portion
of Plume
0 ISO 300 600
aesss
SCALE IN FEET
Existing Monitoring Wells
Horizontal Wells
Well for Off-Base Remediation
Indicates
Approximate Direction
of Groundwater Flow
Travis AFB Groundwater IROD
-------
A.3 SITE LF006 (LANDFILL 1)
A.3.1 Site Background
Site LF006 is the location of old Landfill 1 and covers approximately 17 acres in the
North OU (NOU). Landfill 1 was operated as a burn-and-fill landfill from 1943 through 1950.
Materials disposed of and burned in the landfill consisted primarily of general refuse such as
wood, glass, and construction debris, although some disposal of industrial wastes was reported
(Radian, 1995b). A trailer park was built over a portion of the site in 1970 and is still in use.
The Air Force collected groundwater samples in 12 locations at LF006A during the RI.
Four soil borings were drilled to groundwater, where HydroPunch samples were collected; three
cone penetrometer (CPT) locations were sampled for groundwater; five monitoring wells were
sampled. Groundwater samples were analyzed for petroleum products (diesel, JP4, oil, and
TPH-gasoline), pesticides and PCBs, VOCs, SVOCs, dioxins/furans, gross alpha and gross beta,
and inorganic constituents (Radian, 1995b).
In addition to groundwater sampling efforts, the Air Force collected the following soil
gas, surface emission flux, surface water, sediment, surface soil, and subsurface soil samples
from the entire NOU: approximately 286 shallow subsurface soil gas samples at 3 feet depth;
24 surface emission flux sampling locations; 22 sediment samples; 6 surface water samples;
surface soil samples from 59 soil boring locations to determine if contamination was present; and
subsurface soil from 52 soil borings and 7 monitoring wells. Sampling locations, constituents
analyzed, and results are presented in the NOU RI (Radian, 1995b).
VOCs are the only COCs detected in the groundwater at the site during the RI. They
include TCE, 1,1-DCE, and TPH.
Travis AFB Groundwater IROD A-12 as of 3 December 1997
-------
Site location, contaminant concentrations, and a conceptual site model are presented in
Figure A-3. The general extent of groundwater contamination is shown; the sampling results do
not indicate plumes that can be defined by concentration isopleths. The detected concentrations
indicate pockets of contamination that vary by location and show no increasing or decreasing
pattern that could be contoured. The northern area of contamination is related to TPH only; the
southern area of contamination includes TCE, TCE degradation by-products, and TPH.
A.3.2 Feasibility Study
The alternatives evaluated in the FS for LF006 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had similar scores ranging from 27 to 29.
Costs were $860,000 capital with $100,000 O&M for Alternative 3; $880,000 capital with
$130,000 O&M for Alternative 5; and $640,000 capital with $61,000 O&M for Alternative 7.
A.3.3 Selected Interim Remedial Actions/Objectives
The selected interim action for groundwater at LF006 is Alternative 2, Natural
Attenuation in conjunction with groundwater monitoring. Alternative 2 is a cost-effective way to
meet CERCLA criteria, though at a slower rate than Alternative 3, for sites that have low
concentrations (maximum 330 ug/L TPH, maximum 20 ng/L TCE) and stable plumes. The
site-specific characteristics of LF006 and the groundwater sample results from the RI and 1996
quarterly sampling events provide evidence that natural attenuation is a viable remediation
alternative. For instance, the clustered areal distribution of TCE concentration results within
LF006 were low (highest detection limit was 20 ng/L TCE at location CPT-2) and, therefore, are
Travis AFB Groundwater IROD A-l 3 as of 3 December 1997
-------
susceptible to stabilization via natural attenuation. Also, with the presence of TPH at LF006,
TCE may indirectly be cometabolized as TPH is utilized as an energy source by bacteria.
Furthermore, dichloroethenes, such as cis-1,2 DCE and 1,1-DCE, daughter products of the
biodegradation of TCE, were detected in a number of monitoring wells, soil borings, and CPTs
located in the southern portion of Site LF006 (Table A-l). Because dichloroethenes were not a
primary/initial contaminant, data suggest that natural attenuation may be occurring via reductive
dehalogenation of TCE. The effect of natural attenuation on reducing contaminant toxicity,
mobility, and/or volume, will be documented by monitoring at strategic locations. The details of
the monitoring will be included in the remedial design for the site.
A.3.4 Conceptual Site Model
Leaching from the buried waste material appears to have been the source of the
groundwater contamination at LF006. There are no COCs for subsurface soil or surface soil at
this site.
Travis AFB Ground water 1ROD A-14 as of 3 December 1997
-------
LF006 (Landfill 1, Area A)
TCE Plum.
(TCE, 1.1-OCt TW1)
(TPMMOMB/t)
bn»i« Montonng WMi
. InOeim Apprimrmn
D**cto" C* OfOVMtMVMr Flow
PflffiMy Cafrif^hiMlA. ftflm*rll»llAn Drlvvrla and AH**!** u*dla
Contaminant
Maelwn T»p«
Groundwater VOCl
Qreundwattr VOCt
Groundwalar TPH
Rarmdtatlofi
Driver
HR - 6.3 > 10 *
Hfl- t.7.10'*
tM
Conltffllfunl
el Concirn
KE
1.1 DCE
NA
Mulmum
Rtpertwl
ConctMrMlon
20»g/l
064^9/t.
330 /igrt.
• Moitly Dal gruiland
• MoM* home* covw ipp'OKlnwldy 40% e( Itw Mudy •'•» (nxtloxst portion)
• Ornncg* ditclwt Bimpon lurtKt waltr to ttv loulti and «ui
• TCE in groundwutr — Sjig/V- •vtrioi. J0*gl. maximum
• TPH in gnundwitir — iTOfigA (Wtg*. 330«imum
ttimMtd eonumtnttKj groxidwMtr turlK* VM - 440.000 ft* vaiunw . 2.200.000 II1
• DipmtogreundinMr — 10lM«
• Opth to b»»w* — SO IMI
• Mor» ftmrn^Uf H*t*\* (lino* md ««l) b»l»Mn 25 IK< bqt t-x) b»o>edi
• MttnMiv* 2: Mlunt AntnuMion/KlonllonXg tor TPHonry tnl TCE pkxnn
• Alternative 2: Natural ManuatlorvMonrioring: Capital Cotl - lie.WO; First Year O & M - 173.000
> Alternative 3: Extraction, Treatment end Discharge
• FSMemeDveS: A* Slnpper/Calaly«cOxkMlon.IonEJcnangi. ActivatedCarbon:
Capital Cost . IMD.OOO: FM >tar OI M . 1100.000
• FS Mtmattve 5: UVOiMallon, Ion Eienange.ActivMed Carton:
> MM.OOO: FVtri Vear 0 < U - 1130.000
T: Ion Exchanoa. Aaiveted Carbon:
Captal Con - 1040.000; Firil Yf w O t M - let .000
• These cost* detved from FS wil be refined dunng trie remedial design phase
based on eombmMlon of alternatives and site specific variables
Interim Design AMI
• Montomg W*M (NOTE: location and numbar ot wtn> win ba diltrmrwd during th» remedial dciign pha»)
• Sampling u Conftrm Stability otPlumaSiia and Rat* of Nattnl Antrualion
Figure A-3.
Site Summary Information
for LF006. Tnvls AFB
A-15
wofJUtci
-------
A.4 SITE LF007 (LANDFILL 2, AREAS B, C, AND D)
A.4.1 Site Background
Site LF007 is located at old Landfill 2 and occupies approximately 73 acres in the
NOU. The landfill was operated in a trench-and-fill method beginning in the early 1950s
following the closure of Landfill 1. The landfill was used primarily for the disposal of general
refuse such as wood, glass, and construction debris. Small amounts of industrial wastes and fuel
sludges from tank cleaning operations were also reported to have been disposed of at Landfill 2
(Radian, 1995b). Use of Landfill 2 ceased in 1974. From the early 1950s until 1964, a portion of
the eastern part of the landfill was used for storage of excess and waste materials including oils,
hydraulic fluid, and solvents for resale or disposal. As determined by aerial photographs, a skeet
range was also located at the site around 1953; however, the exact dates of operation are not
known (Radian, 1995b). Current operations at the site are limited to those conducted at Buildings
1360, 1365, and 1370. Building 1360 is the Affiliate Radio System, Building 1365 is used for
hazardous waste storage, and Building 1370 houses the Small Arms Range. Artificial vernal
pools (created by landfill subsidence), which may contain the endangered species fairy shrimp,
are located at the site. Groundwater does not discharge to the vernal pools.
The Air Force collected groundwater samples from 30 locations at LF007. Twenty-
eight HydroPunch® samples were collected from soil borings, and two monitoring wells were
sampled. Groundwater samples were analyzed for petroleum products (diesel, JP4, oil, and
TPH-gasoline), pesticides and PCBs, VOCs, SVOCs, dioxins/furans, gross alpha and gross beta,
and inorganic constituents (Radian, 1995b).
In addition to groundwater sampling efforts, the Air Force collected the following soil
gas, surface emission flux, surface water, sediment, surface soil, and subsurface soil samples
from the entire NOU: approximately 286 shallow subsurface soil gas samples at 3 feet depth,
24 surface emission flux sampling locations, 22 sediment samples, 6 surface water samples;
Travis AFB Groundwater IROD A-16 as of 3 December 1997
-------
surface soil samples from 59 soil boring locations to determine if contamination was present; and
subsurface soil from 52 soil borings and 7 monitoring wells. Sampling locations, constituents
analyzed, and results are presented in the NOU RI (Radian, 1995b).
Ground water contamination has been found in three areas of the site, referred to as
Areas B, C, and D. These are general areas of groundwater contamination; plumes with
decreasing concentration isopleths could not be identified because of the nature of the landfill
operation, and in part to a lack of migration away from the trench areas. Classes of COCs
detected in the groundwater during the RI at Area B include VOCs, one SVOC, one PCB, and
one dioxin. VOCs in Area B include benzene, 1,4-dichlorobenzene, and chlorobenzene, and the
SVOC is bis(2-ethylhexyl)phthalate. PCB-1248 and 2,3,7,8-TCDDeq (a dioxin) were also
identified as COCs at LF007B. VOCs make up all COCs detected at Area C during the RJ, and
include TCE, vinyl chloride, 1,1-DCE, 1,2-DCA, and 1,2-dichloropropane. Due to a local
anomaly in the groundwater flow direction beneath Area C, contamination from this area has
migrated off base. Classes of COCs identified at Area D include VOCs, one dioxin, one PCB,
and one SVOC. VOCs include benzene, vinyl chloride, 1,4-dichlorobenzene, 1,1-DCE, and
chlorobenzene. COCs also include bis(2-ethylhexyl)phthalate (a SVOC), PCB-1242, and
2,3,7,8-TCDDeq (dioxin). Site locations, contaminant concentrations, and conceptual site models
for the three areas are presented in Figures A-4, A-5, and A-6. In addition, TPH (up to
4,200 ug/L at Area B, 390 ug/L at Area C, and 6,500 ug/L at Area D) has been detected in all
three areas during sampling efforts conducted at the site. Contamination including PCBs, metals,
and several SVOCs were detected in the surface soils at various location throughout the site
during the RI.
A.4.2 Feasibility Study
The alternatives evaluated in the FS for all three areas of LF007 were Alternative 1
(no action), Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air
stripper/catalytic oxidation, ion exchange, activated carbon, and discharge), Alternative 5
Travis AFB Groundwater IROD A-17 as of 3 December 1997
-------
(extraction, UV-OX, ion exchange, activated carbon, and discharge), and Alternative 7
(extraction, ion exchange, activated carbon, and discharge). As evaluated in the FS Alternatives 1
and 2 had similar costs and scores for each of the three areas of LF007 as follows. Alternative 1
had the lowest cost, but also the lowest total score. Alternative 2 had a capita] cost of $18,600,
first year O&M cost of $72,000, and a score of 16. For all three areas evaluated Alternatives 3, 5,
and 7 had similar scores, ranging from 27 to 29, but differing costs. For Area B the capital and
first year O&M cost for the three alternatives were $770,000 capital with $105,000 O&M for
Alternative 3; $815,000 capital with $133,000 O&M for Alternative 5; and $550,000 capital with
$72,000 O&M for Alternative 7. For Area C the costs were $615,000 capital with $94,000 O&M
for Alternative 3; $675,000 capital with $115,000 O&M for Alternative 5; and $450,000 capital
with $58,000 O&M for Alternative 7. For Area D the costs were $1.8 million capital and
$224,000 O&M for Alternative 3; $1.8 million capital and $266,000 O&M for Alternative 5; and
$1.8 million capital and $266,000 O&M for Alternative 7.
A.4.3 Selected Interim Remedial Actions/Objectives
Selection of an alternative for the on-base Areas B and D at LF007 is deferred until the
final Groundwater ROD so that additional data can be collected and evaluated to support the use
of natural attenuation as a remedial alternative. Additional site-specific data regarding natural
attenuation will be developed and evaluated as part of the Basewide Natural Attenuation
Assessment Plan. Natural attenuation appears to be a viable alternative for both of these areas
because of the small areal extent of contamination or the irregular distribution of contaminants
that would make it difficult to design an extraction system that would be both technically
effective and cost-effective. In addition, the presence of TPH (needed for cometabolism) and the
presence of TCE degradation products indicate that conditions are present for natural attenuation
to occur. Groundwater monitoring will be used to determine if contaminant migration is
occurring, and if surface water infiltration has any impact on contaminant concentrations.
Travis AFB Groundwater IROD A-l 8 as of 3 December 1997
-------
For contamination at Area C, the selected interim action includes a combination of
migration control and remediation of off-base contamination. This action will be accomplished
through extraction and treatment of the contaminated ground water. Migration control on base
will limit the possibility of further off-base migration of contaminants. Active extraction is the
selected interim action because contamination has migrated off-base. If any portion of Area C
was on-base, selection of an alternative would be deferred, and natural attenuation would be
evaluated. Natural attenuation appears to be a viable alternative because of the small areal extent
of contamination, TCE concentration less than 100 ng/L, the presence of TPH for cometabolism
and the presence of degradation products that indicate natural attenuation is occurring. Natural
attenuation with groundwater monitoring will be assessed for the on-base portion of the plume.
A.4.4 Conceptual Site Model
Soil contamination found in LF007 Areas B and D may be related to contamination in
the groundwater found in these areas. Remediation of the surface and subsurface soils in these
areas that reduces infiltration of rainwater and improves drainage may reduce the potential for
vertical migration of contaminants.
A.4.5 Special Site Conditions
The current specified interim remedial action at LF007C is Alternative 3 for the portion
of the plume that is off-base. If the plume were entirely on Travis AFB property, selection of an
alternative would be deferred until the final Groundwater ROD.
Travis AFB Groundwater IROD A-19 as of 3 December 1997
-------
LF007 (Landflll 2, Area B)
Primary CmtainlnHitft, A«**A*Mft*tIafi Drivtm pnd ^flattied M*d 1
U*uMat*«*j
MVUHIRI
Oroundwatar
GroundwaWr
Qioundwalar
Grouxlwalar
Oioundwatar
Qraundwatat
Camambtanl
IVP«
VOCi
VDCi
VOC.
svoci
PMicMai/PC8t
Dxunm
Htmadlallen
DiWaf
HB. 39,io5
Hfl . t.9 1 10s
M. )J
MR - 4.\ i IO* 1
MR. 7.0 1 10"*
MR- 1J«104
Cerlamlnant
ef Concam
Bfniena
1 .*-dlcf kxotwntana
Chlo otxnten*
lm(2-affiY haiyijpnihalata
PCB» 'PCB-^iei
2J.7.8-TCDOaq
Mulmum
Rapottd
Concanlratlon
59.3 ii 9*.
xe/ign.
iei pg/1
l4.3«gA.
t3.S«ig/L
0.55 pgA
• Mosny g>nty n«t«nd«
• OiKir*i« ro*d
• BMUMW m gromhraur — 30>rgA. tvcrigi. 59.3 pg/l mailnur.
• CHorabmnn* In graunctmicr — 30^g/L iwng*, 151 pg/i mc^inun
«« - «00.000 (T «oKn» . 2,000.000 fP
• DipmtogrountfMW — 10I**«
• OpOllOb«>tK* — 40IMI
• B*eK« •tdhndMiraMrW ringing mxn Olo t5 to* bfl»
• Wwmmirt Icytra ol ctayi *nd Mndi bMw*«n tondfin rnnwW md » IMI bgs
• (Mwnd; Am wN b* lnelud*4 In BoMM* NMural An«nu«ian Atmwmni Plan
«nd A
• AlunwiiM £ Ndural MMnuMnnrtitamonng: C^XUI Coa - I1B.900. Pint Y»w 0 & M • 172.000
• MtnWHIv* 3: Extraction. Tnotnonl «nd Dncturg*
• F8 AlUmdly* 3: Mr 8«pP«««*y1>e Oittttion. Ion Exchange. AdlvMtd Cwtoo:
C*prt«l Can • $770.000: Fint Ykw O & M • $105.000
• FS AlttmaSv* S: UV OiMttkxi. tan E>eh»ig». Aciwncd C«rt>on
Capital Cr 1 [kcimk* 1*97
-------
Conceptual Model
Bate Boundary
LF007 (Landfill 2, Area C)
Primary Catitamlii»iit« PernedlalkHt Driver* a
Medium
Croundwalaf
Groundweter
GroundwsJer
Groundwaler
Qroundweler
Conlimln«n<
Type
VOC$
voc«
voc»
VOCl
VOCi
RsmedlsUen
Driver
Contemlnant
of Concern
HR-I8H0
5
TCE
WyCNortO*
HROSiilO I I-OCE
HB-LSitO* 1.2-OCA
HH - 1 .0 1 10 ' 1 ,2-dkttoropropan*
Mulmum
Reported
Concentration
49.10oA
O.IM^grt.
0.297 *g/l
0.314 jigrt.
3.38^0/1-
fltta Chmettftitlc*
UM. grassy, **> immpy •»•
Ttevn AFB DoonOwy bnecti the rtuOy en* w(!t\ ent^wml tone*
Northern helf of study area n pnVat*tyiQA aaga. 4C.I «igA. manirrun
Estimertd tortmymed greundwaer turtac* arei - 830.000 tf. volume-
E«twna»ed man of c*e»orv»d VOCa equari 1 .5 fx no evidence ol ONAPL or IMAPl
OepmioqnMiBoelet — v»rte»>rcm I »IOIe«l.deper»o>iqone«eeon
Depth Bbedroe*- 30 toet
Low pammWy aoDi (ediy) to «boul 20 lee» bg»
8W tentea benveen M kMt bgi and bedrock
8*» eteo emdtoc tar eon eont«n*iaeon
aed •aertm
• Mamcttve 3: EMrKVon, Treatment and Oadwg* (lor Ofl-BMe PorKon)
• Mljrenon Control
-OfT-t>e«»RemeoTaoon
NanntABanu
nlPlan (It plume vereenUrery on be**. MiMlon vroutd be
deferred tor entire pfcme ami Induded ti tie BaeewMe NMunl Altenuaion Aaeeetment Pun)
• AKernMlve 2: Ntnm AnenmnporvVonrtortng: Capxal Cotl • 118.900; Fnt Year 0 » M •
• Mimattvt 3: Ertrerton. T'eMment and Oriehtrge
• fS Memattv* 3: Mr Strlpper/Catarytic OnWition. Ion Excnange. Ael«v*t*d Carbon:
CaprUt Cent - $815.000; Fan Year O A M - $94.000
• fS ARematlva S: 0V OndMion, km Encnange, Activated Caibor;
Capital Cott - t«7S.OOO; Fmt V*«r O » M - I1 19.000
• FS Alternative 7: Ion Excnange, AOrvned Carbon:
C«pcU Coet-S490.000:FntV»arOAM-SSa.OOO
• Thete coat* derived from FS oil! be refined during remedial detlpi phase
baeed en eomMnation of •ftemetlvee and iHe ipeerflc variables
nlertff^ Oealqn A
$72.000
• Ihoruontalwee;. 300 leet In tcraened (ength
(NOTE: lx>ce«anindnurr(>erolvre«SOTlbede*errririeddunngt^nmi>o^detlgnphaM)
• EjHraettonnMe IS gpm total
• 6W (set 01 a»ive>anee piping (Irornwet to Ireatrnenliyfiefn) — tlncnlO. senaOPVC
• 300 test of discharge piping — t-Vt Inch K). sen WPVC
200 leet ftom Ireetmenl system to eiWnj power ine
Flpurt A-S.
Site Summary Information
for LF007, Area C. Travis AFB
I A-21
of ) IVcimtaT l*n
-------
LF007 (Landfill 2, Area D)
Primary Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
VOCs
VOCs
VOCs
VOCs
VOCs
Dioxins
Pesticides/PCBs
SVOCs
Remediation
Driver
HR = 1.4 x10'5
HR = 2.9x10'6
HR = 2.5x10'5
HR= 1.1X10"6
HI = 15.5
HR = 2.4x1(T4
HR = 2.2x10"4
HR = 8.2x10'6
Contaminant
of Concern
Benzene
Vinyl Chloride
1,4-dichlorobenzene
1.1 -DCE
Chlorobenzene
2.3,7,8-TCDDeq
PCBs(PCB-1242)
bis(2-ethylhexyl)phthalate
Maximum
Reported
Concentration
25.
1.78|
-------
Conceptual Model
TTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTYTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTYTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTYTTTTTTTTTTYTTTYTTTTTTTTTTTTYTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTT1
TTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTYTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TYYTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTT
Landfill Material TTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTYTTTYTTTTTTT1
/TTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTT
TTTTTTTTTTTTTTT.
TTTTTTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTYTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTT
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
Areas of
Contaminated
Groundwater and Soil
Existing Monitoring Wells
Vernal Pool
Base
Boundary
Travis AFB
Indicates Approximate
Direction of Groundwater Flow
Localized Direction
of Groundwater Flow
0 180 300 600
SCALE IN FEET
t
Travis AFB Groundwater I ROD
-------
A.5 SITE SS015 (SOLVENT SPILL AREA AND FACILITIES 550 AND 552)
A.5.1 Site Background
Site SS015 is located in the northwestern part of the EIOU, covers approximately
3.5 acres, and is comprised of the Solvent Spill Area (SSA) and Facilities 550 and 552. The SSA
covers approximately 1.4 acres east of Facility 550 in an area previously used for stripping paint
from aircraft. Use of this area is not well documented prior to 1981; however, stained soil, visible
in historical aerial photographs indicates that the area was in use prior to 1970. Solvent spills
were reported to have occurred in the area east of Facility 550, however actual dates the spills
occurred is unknown (Weston, 1995a). Approximately 100 to 150 gallons per month of either
methyl ethyl ketone (MEK), toluene, or tetraethylene glycol dimethyl ether (tetraglyme) were
reported to have leaked from or splashed out of work trays used for collecting stripping wastes
during operations at the site.
Facility 550, constructed in 1952, houses a corrosion control shop, a metals processing
shop, a fiberglass shop, and nondestructive inspection operations. Past practices at the corrosion
control shop included discharging wastes to a floor drain that was connected to a sanitary sewer
(Weston, 1995a). Wastes generated included paints, thinners, methyl ethyl ketone, acids, and
stripping wastes.
Facility 552 consists of a fenced, bermed concrete pad constructed in 1964 and
currently used as a temporary hazardous waste collection point. Radomes were chemically
stripped of paint near Facility 552 from 1964 to 1980. Stored wastes include paint, chromic acid,
and solvents generated during aircraft maintenance operations at Facility 550. No documentation
of past spills occurring at the site has been found (Weston, 1995a).
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
Travis AFB Groundwaier IROD A-23 as of 3 December 1997
-------
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RJ (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RJ indicate that nine groundwater samples were
collected from the SSA during Rounds 7 through 9 of the RJ. Samples were analyzed for VOCs,
SVOCs, petroleum products, and inorganic constituents.
In addition to groundwater samples, subsurface soil samples were collected from five
locations in the SSA, two locations near Facility 550, and four locations near Facility 552.
Surface soil samples were collected from five locations in the SSA and from two locations near
Facility 552. Sampling locations, constituents analyzed, and results can be obtained in the EIOU
RJ (Weston, 1995a).
Classes of COCs detected in the groundwater at the site during the RJ included various
VOCs, one SVOC, and one metal. VOCs include TCE, cis-l,2-DCE, vinyl chloride,
1,4-dichlorobenzene, 1,2-DCA, and PCE. Bis(2-ethylhexyl)phthalate (a SVOC) and nickel
(a metal) were identified as COCs. TPH at concentrations up to 4,300 ug/L has also been
detected in the groundwater during periodic monitoring well sampling efforts conducted at the
site. Some solvents, such as MEK, which were reportedly spilled at SS015 were sampled for in
the RJ but not detected, or were detected at levels which did not cause human health risks greater
than one in one million. Figure A-7 presents site location, contaminant concentration in the
groundwater, and a conceptual site model. Contamination detected in the soils at the site
included PAHs and metals (molybdenum, antimony, cadmium, chromium, copper, lead, zinc,
mercury, and silver).
A.5.2 Feasibility Study
The alternatives evaluated in the FS for SS015 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
Travis AFB Groundwater IROD A-24 as of 3 December'1997
-------
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had similar scores ranging from 27 to 31.
Capital and first year O&M costs for these three alternatives were $750,000 capital with
$120,000 O&M for Alternative 3; $850,000 capital with $160,000 O&M for Alternative 5; and
$990,000 capital with $520,000 O&M for Alternative 7.
A.5.3 Selected Interim Remedial Actions/Objectives
Selection of an alternative for groundwater at SS015 is deferred until the final
Groundwater ROD so that additional data can be collected and evaluated to support the use of
natural attenuation. Natural attenuation appears to be a viable alternative for this site because of
the small areal extent of contamination, low TCE concentrations (maximum 25 ug/L), the
presence of TPH for cometabolism, and TCE degradation by-products indicating natural
attenuation is occurring. In addition, the site has relatively low permeability soils, low infiltration
rates due to asphalt on the surface, and the plume appears stable. Additional site-specific data
regarding natural attenuation will be developed for evaluation as part of the final Natural
Attenuation Assessment Plan.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
Travis AFB Groundwater IROD A-25 asof 3 December'1997
-------
A.5.4 Conceptual Site Model
Sources of groundwater contamination appear to be from past spills of materials used or
stored at or near Facilities 552 and 550; however, no residual solvents were detected in the
unsaturated zone. Surface soil contaminants identified at SS015 include PAHs and metals. These
contaminants in soil have not impacted groundwater (i.e., the COC metals in the surface soil are
not the same as the groundwater COC [nickel]), and any anticipated soil cleanup action is not
expected to have an effect on groundwater. The source of nickel is currently being investigated.
Travis AFB Ground water I ROD A-26 as of 3 December 1997
-------
SS015 (Solvent Spill Area and Facilities 550 and 552)
Primary Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant Remediation
Type Driver
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
Metals
TPH
Collective
Human Risk
for These
Contaminants
Is
HR = 7.22x10'*
Potential Ecological
Risk in Surface Water
Contaminant
of Concern
TCE
cis-1,2-DCE
vinyl Chloride
1,4-DCB
1.2-DCA
PCE
bis(2-ethy.hexyl)phthalate
Mickel
NA
Maximum
Reported
Concentration
25/
-------
Conceptual Model
Area of Past
Surface Spill
PAH Contaminated Soil
Groundwater
VOC Contaminant
Concentration
Contours (ug/L)
Area of Metals
Contaminated Soil (Lead)
(Ecological Risk)
• Existing Monitoring Wells
Storm Sewer System
0 75 180 300
2=9=
SCALE IN FEET
Indicates Approximate
Direction of Groundwater Flow
Travis AFB Groundwater IROD
-------
A.6 SITE SS016 (OIL SPILL AREA, FACILITIES 11,13/14,18,20,42/1941,
139/144, AND SELECTED SECTIONS OF STORM SEWER RIGHT OF WAY)
A.6.1 Site Background
Site SS016 is located in the center of the EIOU, covers approximately 210 acres, and is
comprised of the Oil Spill Area (OSA) and Facilities 11, 13/14, 18, 20, 42/1941, 139/144, and
sections of the Storm Sewer Right of Way (SSRW).
The OSA originally encompassed an area where waste oil had reportedly been spilled
or disposed of on a grassy area which is now paved. Based on interviews with base personnel
that indicated past releases from an oil/water separator (OWS) located at Facility 18, the OSA
was expanded. The original area was reportedly used from the mid-1940s to the early 1950s
(Weston, 1995a).
Facility 18 contains the Cleaning and Degreasing Shop which, based on historical
records, once stored large quantities of various solvents. Although Facility 18 is currently still in
use, the OWS holding tank has not been used since 1985.
Facility 11 is located between Hangar Avenue and the flightline, west of Second Street.
Constructed in 1944, Facility 11 is currently used for servicing and repairing flightline support
equipment. Small amounts of hydraulic fluids and oils are used during these activities. Past
operations at the facility included a satellite accumulation point for hazardous wastes. Based on
interviews with shop personnel, solvents were used during the cleaning of aircraft engines. No
documentation of dates of these activities or spills that may have occurred is available (Weston,
1995a).
Travis AFB Groundwaler IROD A-28 as of 3 DeeembeH997
-------
Facility 13/14 was an aircraft wash rack located south of Hangar Avenue between old
Hangars 13 and 14. The Hangars were demolished in 1988 and Building 31 was built at the site.
The wash rack was probably in use from the mid-1950s to the mid-1960s (Weston, 1995a).
Facility 20, located southeast of the intersection of second street and Hangar Avenue, is
the Base Control Tower and was the site of an underground storage tank (UST) used for fuel for
a backup generator. The UST was removed in 1994.
Facility 42/1941, located near Facility 11, includes a hazardous waste storage area and
wash rack. The facility consists of a concrete pad, constructed in 1966, which is partially
enclosed by corrugated metal walls. In addition to the wash rack, four 250-gallon above-ground
storage tanks are located at the facility to hold waste oils and fuels. The wash rack is connected
to the sanitary sewer through an OWS.
Facility 139/144 is comprised of two adjacent facilities, located south of Hickam
Avenue and east of Broadway. Both house vehicle maintenance activities. Facility 139 was
constructed in 1954 and Facility 144 was constructed in 1945. In addition to vehicle
maintenance, other activities performed at the facilities include body work, painting, and radiator
servicing. A leaking, 2,000-gallon solvent UST was removed from Facility 139 in 1985 (Weston,
1995a). Floor drains in the shop direct spills to two OWSs. Past practices at Facility 144 included
emptying the radiator test tank onto the ground at the facility.
The SSRW includes all of the storm sewers, major surface drainage systems, and Union
Creek. Portions of the SSRW in SSO16 drain industrial areas in the EIOU. Miscellaneous base
shops and aircraft parking aprons drain to the storm sewer system. Chemical wastes were
potentially released into the system.
The Air Force conducted nine sampling rounds at sites within the EIOU during the RJ.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
•
Travis AFB Ground water IROD A-29 as of 3 December^997
-------
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RI (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RI indicate that groundwater samples were collected
from 119 locations at SS016 in Rounds 7 through 9. Within SS016, groundwater samples were
collected from the following locations:
• 31 locations along the SSRW;
• 32 locations in the OSA;
• 15 locations in the vicinity of Facility 11;
• 11 locations in the vicinity of Facilities 13/14;
• 13 locations in the vicinity of Facility 20;
• 6 locations in the vicinity of Facilities 42/1941;
• 7 locations in the vicinity of Facility 139; and
• 4 locations "in the vicinity of Facility 144.
Groundwater samples were analyzed for VOCs, SVOCs, dioxins/furans, petroleum products,
inorganic constituents, total dissolved solids, and total organic carbon.
In addition to groundwater samples, the following were collected:
• 14 surface soil samples, 17 surface water samples, subsurface soil samples from
7 soil borings, and 35 sediment samples from the area surrounding the SSRW;
• Subsurface soil samples from 4 soil borings and 3 surface soil samples from the
OSA;
• Subsurface soil samples from 6 soil borings in the vicinity of Facility 11;
• Subsurface soil samples from 6 soil borings in the vicinity of Facilities 13/14;
Travis AFB Groundwater IROD A-30 as of 3 DecemberT997
-------
• Subsurface soil samples from 6 soil borings and 3 surface soil samples from the
vicinity of Facility 20;
• Subsurface soil samples from four soil borings in the vicinity of Facilities
42/1941;
• Subsurface soil samples from five soil borings and one surface sample in the
vicinity of Facility 139; and
• Subsurface soil samples from four soil borings and four surface soil samples
from the vicinity of Facility 144.
Sample locations, constituents analyzed, and results can be obtained in the EIOU RI (Weston,
1995a).
Results from the sampling of the Storm Sewer Right-of-Way during the RI indicated
that TCE concentrations in surface water within the storm sewer remained fairly consistent
between samples collected from the east end of the storm sewer and Outfall III (23 to 55 ug/L).
BTEX concentrations were highest in surface water near MW-246 area.
COCs detected in the groundwater at the site during the RI consist primarily of VOCs,
and also include one SVOC and one metal. VOCs include TCE, cis-l,2-DCE, vinyl chloride,
benzene, chloroform, 1,4-dichlorobenzene, dichlorobromomethane, 1,2-DCA, 1,1-DCE, and
PCE. Bis(2-ethylhexyl)phthalate (a SVOC) and nickel (a metal) were also identified as COCs.
TPH was identified in the groundwater at concentrations up to 8,500 ug/L. Recent CPT data has
detected TCE levels at SS016 up to 180,000 ug/L, but results may not be comparable to
monitoring well data. Data from the RI is presented in Figure A-8. Site location, contaminant
concentrations, and a conceptual site model are presented in Figure A-8. Contaminants identified
in the soil at the site include PAHs and PCBs.
An ongoing removal action at SS016 is known as the Tower Area Removal Action
(TARA). The TARA system includes extraction wells, a carbon treatment system, and discharge
Travis AFB Groundwater IROD A-31 as of 3 December"T997
-------
to irrigation lines or the storm sewer. TARA was designed and operated to remove high
concentrations of VOCs in the groundwater and also to protect workers during construction of a
hydrant system near the tower. The system has removed over 190 pounds of contaminants since
the system began operation in 1995. The TARA extraction system is being expanded to include
another area of high concentrations of VOCs at the OSA. The system will extract groundwater
from the OSA and link the TARA extraction well with a new treatment system.
A.6.2 Feasibility Study
The alternatives evaluated in the FS for SS016 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. These costs are for the Oil Spill portion of SS016, and do not include
the "Remainder of Plume" costs which were calculated separately in the FS. Alternative 2 had a
capital cost of $18,600, a first year O&M cost of $72,000, and a score of 16. Alternatives 3, 5,
and 7 all had scores of 27. Capital and first year O&M costs for the three alternatives were
$2.88 million capital with $274,000 O&M for Alternative 3; $3 million capital with $312,000
O&M for Alternative 5; and $7.1 million capital with $5.9 million O&M for Alternative 7.
A.6.3 Selected Interim Remedial Actions/Objectives
The selected interim action for SS016 is extraction, treatment, and discharge for source
and migration control. Source control is selected for SS016 because TCE concentrations are
greater than or equal to 3,000 ug/L and DNAPL is suspected in the OSA area. Migration control
is necessary in distinct areas with high VOC concentrations. Extraction will control contaminant
migration by creating a reversal in both flow and concentration gradients. Monitoring will
confirm effectiveness of source and migration control. Additional extraction wells will be
Travis AFB Groundwater IROD A-32 as of 3 DecembeM997
-------
installed if required to ensure the plume is stable. Design installation, operation, and maintenance
of the wells will take into consideration the fact that portions of the plume are under active
runways and taxiways.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
A.6.4 Conceptual Site Model
Groundwater contamination in SS016 is extensive with several areas of higher (greater
than 1,000 ug/L) TCE concentrations. There is an area of potential interaction between
contaminated groundwater and storm sewers in the southern portion of the site (see Figure 3-6)
(Weston, 1995a). Soil contamination, including PAHs and PCBs, was found in a small area of
site SS016. These contaminants in soil have not impacted groundwater, and any anticipated soil
cleanup action is not expected to have an affect on groundwater.
Travis AFB Groundwaier IROD A-33 as of 3 DecemberT997
-------
SS016 (Oil Spill Area, Facilities 11,13/14,18, 20, 42/1941,139/144,
|and Selected Sections of Storm Sewer Right of Way)
^Primary Contaminants. Remediation Drivers and Affected Media
Medium
Contaminant
Type
Remediation
Driver
Contaminant
of Concern
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
Metals
Collective
Human Risk
for These
Contaminants
HR = 1.11 x10'2
TCE
cis-1,2-DCE
Vinyl Chloride
Banzene
Chloroform
1 4-DCB
Dichlorobromomethane
1,2-DCA
1.1-DCE
PCE
bis (2-ethy!hexyl)phthalate
Nickel
Maximum
Reported
Concentration
32,000 ;
-------
Conceptual Model
Underground
Storage Tank
Alluvium
(clays, silts, sands)
Extent of PCB
and PAH Soil
Contamination
(Human
Health Risk)
i KH bxteni in
Groundwater
•^ /••^•"^ f
>mours v*g/\-)
Groundwater
§• gmamma^m
^7 ^
ff- Site Boundary
Indicates Approximate
Direction of Groundwater Flow
— — Storm Sewer System
Travis AFB Groundwater IROD
-------
A.7 SITE SS029 (MW-329 AREA)
A.7.1 Site Background
Site SS029 consists of approximately 5.5 acres around Monitoring Well (MW) 329 in
the southern part of the EIOU just south of the runway. The monitoring well was installed at the
request of the Air Force Center for Environmental Excellence (AFCEE) to evaluate the source of
the TCE plume identified at MW-269 (Weston, 1995a). Historical aerial photographs show
aircraft parked in the area; however, activity appears limited and no source for the plume has
been identified.
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RI (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RI indicate that groundwater samples from Rounds 7
through 9 were collected from three monitoring wells and eight CPT locations at SS029. Samples
were analyzed for VOCs, SVOCs, inorganic constituents, and petroleum products. In addition to
groundwater sampling, subsurface soil samples were collected from three soil borings at SS029.
Sampling locations, constituents analyzed, and results are presented in the EIOU RI (Weston,
1995a).
All COCs identified in the groundwater during the RI were VOCs. They include TCE,
1,2-DCA, cis-l,2-DCE, benzene, chloroform, 1,1-DCE, and vinyl chloride. Site location,
contaminant concentrations, and a conceptual site model are presented in Figure A-9. Additional
contaminants including VOCs, SVOCs, PAHs, and metals were identified in the soils at the site.
Travis AFB Groundwater IROD A-35 as of 3 DecemberT997
-------
A.7.2 Feasibility Study
The alternatives evaluated in the FS for SS029 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 4 (extraction, air stripper/catalytic
oxidation, activated carbon, and discharge), Alternative 6 (extraction, UV-OX, activated carbon,
and discharge), and Alternative 8 (extraction, activated carbon, and discharge). As evaluated,
Alternative 1 had the lowest cost, but also the lowest total score. Alternative 2 had a capital cost
of $18,600, a first year O&M cost of $72,000, and a score of 16. Alternatives 4, 6, and 8 had
similar scores ranging from 27 to 29. Capital and first year O&M costs for these three
alternatives were $1.6 million capital with $170,000 O&M for Alternative 4; $1.7 million capital
with $210,000 O&M for Alternative 6; and $1.75 million capital with $660,000 O&M for
Alternative 8.
A.7.3 Selected Interim Remedial Actions/Objectives
The selected interim action for SS029 is Alternative 3, Extraction, Treatment, and
Discharge. Migration control is to contain the migration of contaminated groundwater. In
addition, portions of the site are deferred until the final Groundwater ROD so that additional data
can be collected and evaluated to support the use of natural attenuation.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
Travis AFB Groundwaler IROD A-36 as of 3 DecembeTl997
-------
A.7.4 Conceptual Site Model
A source of groundwater contamination in the area of MW-329 has not been identified;
however, an aerial photograph of the area indicates that aircraft once parked at the site.
Investigations were conducted at SS029 to assess the extent of TCE contamination downgradient
of the SSO16 plume.
Contaminants found in the soils at site SS029 include TCE, several PAHs, and metals.
Based on modeling results, low soil TCE levels (0.12 mg/kg) indicate that the soil is not a source
for the TCE groundwater contamination. Therefore, any soil cleanup action is not expected to
have an effect on groundwater.
There is a potential for groundwater/storm sewer interaction on the western edge of the
site.
Travis AFB Groundwater IROD A-37 as of 3 DecemberT997
-------
SS029 (MW-329 Area)
Primary Contaminants. Remediation Drivers and Affected Media
Maximum
Contaminant Remediation Contaminant Reported
Medium Type Driver of Concern Concentration
Groundwater VOCs Collective TCE 1,300/*g/L
Groundwater VOCs Human Risk 1.2-DCA 1.13//9/L
Groundwater VOCs for These cis-1.2-DCE
Groundwater VOCs Contaminants Benzene
Groundwater VOCs ls Chloroform 0.61
Groundwater VOCs HR = 422x10'4 1.1-DCE 0.57 ftg/L
Groundwater VOCs ' Vinyl Chloride 0.22 fig/L
Site Characteristics
• Open field is located between abandoned taxiway and Union Creek
• TCE in groundwater — 315 ^g/L average, 1,300 ftg/L maximum
• Estimated contaminated groundwater surface area = 800,000 ft5; volume = 4,800,000 ft3
• Estimated mass of dissolved VOCs equals 100 Ib; no evidence cf DNAPL or LNAPL
- Depth to groundwater — 10 feet
• Depth to bedrock — 30 feet
• Top 10 feet of saturated alluvium is composed of clays and other low permeability material
• Bottom 10 feet of saturated alluvium is composed of sands and other moderate permeability material
• Site also studied for surface soil contamination
• Storm sewer is potential groundwater/surface water pathway on western edge of site
Selected Interim Remedial Action/Objectives
• Alternative 3: Extraction, Treatment and Discharge
- Migration Control
Feasibility Study Treatment Alternatives and Associated Costs
• Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $18,600; First Year O & M = $72,000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 4: Air Stripper/Catalytic Oxidation, Activated Canon:
Capital Cost = $1,600,000; First Year O & M = $170,000
- FS Alternative 6: UV Oxidation, Activated Carbon:
Capital Cost = $1,700.000; First Year O & M = $210,000
- FS Alternative 8: Activated Carbon:
Capital Cost = $1.750,000; First Year O & M = $660,000
• These costs derived from FS will be refined during the remedial resign phase
based on combination of alternatives and site specific variables
Interim Design Assumptions
• 2 horizontal wells, 300 feet in screened length
(NOTE: Location and number of wells will be determined during the remedial design phase)
• Extraction rate 30 gpm total, 15 gpm from each well
• 1,200 feet of untreated water piping (from well to treatment system) — 1 inch ID. sch 80 PVC
• 600 feet of discharge piping (to Union Creek) — 3 inch ID, sch 80 PVC
350 feet from treatment system to existing power line
Figure A-9.
Site Summary Information
for SS029, Travis AFB
SSS029.CDR • VMG 6/19/97 SAC 1
A-38 as of 3 December 1997
-------
Conceptual Model
^^^^^^^^^^^^^fm^sm
^^^^^^"-^-^^Sfe^B^^
*^«5;fjj^aX^S^^^ij'.v-^^^E5i;2*W(i's^»S>»-*.rfM: BeHf°C
^s^^^^^%^fj=^"^^^^^^i%3H^f
North
TCE Concentration
Contours (ug/L)
Extent of PAH
Contamination in Soil
(Human Risks)
Treatment
System
Untreated '«
^, Water Piping {£
Discharge Piping
Existing Monitoring Welts
Indicates Approximate
Direction of Groundwater Flow
Horizontal Wells
0 ISO 300 600
SCALE IN FEET
Iravis AFB Groundwater IROD
-------
A.8 SITE SS030 (MW-269 AREA)
A.8.1 Site Background
Site SS030 covers approximately 16 acres in the area around MW-269 in the southern
portion of the EIOU near the south base boundary. The monitoring well was originally installed
to evaluate the water quality along this base boundary (Weston, 1995a). The site is adjacent to a
radar facility (Facility 1125); however, historical aerial photographs do not indicate any staining
in the area, or any activities that may have been the source of the groundwater contamination at
SS030.
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RI (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RI indicate that 17 groundwater samples were
collected from monitoring wells and 10 groundwater samples were collected from CPT locations
during final sampling rounds. Samples were analyzed for VOCs, SVOCs, PCBs, petroleum
products, inorganic constituents, and total dissolved solids. In addition to groundwater sampling,
subsurface soil samples were collected from five soil borings, and six surface soil samples were
collected from SS030. Sampling locations, constituents analyzed, and results are presented in the
EIOU RI (Weston, 1995a).
COCs detected in the groundwater at SS030 during the RI include various VOCs and
one metal. VOCs identified as COCs include TCE, chloroform, dichlorobromomethane, and
1,2-DCA. Nickel was identified as a metal COC. The TCE plume extends beyond the base
boundary. The maximum reported TCE concentration from the RI is 2,400 ug/L. Samples taken
after the RI (November, 1995) indicate a maximum concentration of 3,860 ug/L TCE. Site
location, contaminant concentrations, and a conceptual site model are presented in Figure A-10.
Travis AFB Groundwater 1ROD A-39 as of 3 December~?997
-------
Contamination identified in the soils at the site include low levels of several VOCs, SVOCs,
PAHs, and metals (antimony, beryllium, barium, chromium, copper, lead, nickel, selenium, and
zinc). Soil contamination will be addressed separately in a soil ROD.
Early removal actions at this site included a 10-month pump and treat project conducted
by Weston in 1993/94 and a week-long 2-phase extraction test conducted by Radian in 1995. The
objective of these extraction tests was to develop data to design a system to remediate the
groundwater. A Treatability Study is planned for SS030 to extract and treat contaminated
groundwater; startup is planned for the summer of 1997.
A.8.2 Feasibility Study
The alternatives evaluated in the FS for SS030 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 all had total scores of 31. Capital and first
year O&M costs for these three alternatives were $660,000 capital with $106,000 O&M for
Alternative 3; $730,000 capital with $131,000 O&M for Alternative 5; and $490,000 capital with
$78,000 O&M for Alternative 7.
A.8.3 Selected Interim Remedial Actions/Objectives
The selected interim action for SS030 is Alternative 3, Extraction, Treatment, and
Discharge of the groundwater, a combination of remediation of off-base contamination, source
control, and migration control. Source control is necessary to address TCE concentrations
Travis AFB Groundwater IROD A-40 as of 3 DecembeM997
-------
(greater than 3,000 ug/L). Migration control will ensure that further off-base contamination does
not occur.
A.8.4 Conceptual Site Model
No specific sources were identified for SS030; a possible source was identified as the
septic system or associated leachfield. Groundwater contamination extends approximately
1,100 feet beyond the base boundary.
Contamination found in the soils at SS030 includes several VOCs, SVOCs, PAHs, and
metals. Although TCE is found in both the soil and the groundwater, the relatively low levels in
the soil (0.197 mg/kg) and modeling results indicate that it is not a source for the groundwater
contamination. Although nickel is reported as a COC for both soil and groundwater, the actual
origin of the nickel in groundwater is currently being investigated by the Air Force. Any soil
cleanup action is not expected to have an effect on groundwater.
Travis AFB Groundwaier IROD A-41 as of 3 DecembeM997
-------
SS030 (MW-269 Area)
Primary Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant Remediation
•type
VOCs
VOCs
VOCs
VOCs
Metals
Driver
Collective
Human Risk
for These
Contaminants
ls
HR = 7.6x10'4
Contaminant
of Concern
TCE
Chloroform
Dichlorobromomethane
1,2-DCA
Nickel
Maximum
Reported
Concentration
2,400 ng/L
0.
0.34 /jg/L
903 mg/L
Site Characteristics
• Approximately 25% of the area is covered by pavement or buildings
• TCE in groundwater — 958/^g/L average. 2.400//g/L maximum^
• Estimated contaminated groundwater surface area = 425,000 ft2; volume = 6,375,000 ft3
Estimated mass of dissolved VOCs equals 18 Ib; DNIAPL may be present
• Se and Ag were measured at concentrations greater than NPDES discharge limits
in some monitoring wells
• Mix of low permeability soils (clay and silt) and more permeable materials (sands and silts)
to a depth of between 20 and 25 feet bgs
• Depth to groundwater — 10 feet
• Depth to bedrock — 20 to 25 feet
• Site also studied for surface and subsurface soil contamination
Selected Interim Remedial Actlon/Obfecth/aa
• Alternative 3: Extraction, Treatment and Discharge
- Off-base Remediation
- Source Control for TCE
- Migration Control
Feasibility Study Treatment Alternatives and Associated Costa
Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $18,600; First Year O & M = $72,000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 3: Air Stripper/Catalytic Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $660,000; First Year O & M = $106,000
- FS Alternative 5: UV Oxidation, Ion Exchange. Activated Carbon:
Capital Cost = $730,000; First Year O & M = $131,000
- FS Alternative 7: Ion Exchange, Activated Carbon:
Capital Cost = $490,000; First Year O & M = $78,000
• These costs derived from FS will be refined during the remedial cesign phase
based on combination of alternatives and site specific variables
Interim Design Assumptions*
• Five vertical wells and one horizontal well/extraction trench
(NOTE: Location and number of wells will be determined during temedial design phase)
• Extraction rate 92 gpm total, approximately 15 gpm from each well
• 1,300 feet of untreated water piping (from well to treatment system) — 2 to 4 inch PVC or HOPE
• 300 feet of discharge piping (to Union Creek)
* Based on current Treatability Study, RD/RA will refine interim actian
Figure A-10.
Site Summary Information
for SS030, Travis AFB
5SS030COR VMG 8;'9i97SAC I
A-42
asoH December 1997
-------
Conceptual Model
Leach Reid
Base
Boundary
Alluvium
(Clays, Silts, Sands)
Extent of Metals and PAH
Contamination In Soil
., Untreated Water Piping
Base Boundary
' Discharge
/ Piping
Extent of Metals
Contamination In Soil
(Ecological Risk)
Treatment
System
/ Horizontal Well
/ for Migration Control
Off-Base Portion of Plume
Groundwater
Contamination (NO)
Existing Monitoring Wells
Indicates Approximate
Direction of Groundwater Flow
Travis AFB Groundwater I ROD
-------
A.9 SITE SD031 (FACILITY 1205)
A.9.1 Site Background
Site SD031 covers approximately 5.5 acres and encompasses Facility 1205 in the
northeastern part of the EIOU, southeast of Vandenberg Drive. Operations at the facility,
constructed in 1957, include maintenance and repair of diesel-powered generators. A wash rack,
located just south of the facility, is used to clean diesel engine parts and discharges to an OWS.
Wastes generated at the facility include oils, antifreeze, and solvents. Based on interviews with
base personnel, an incinerator may have been located north of the site at one time (Weston,
1995a). Historical aerial photographs taken from 1958 to 1963 indicate that the facility may have
been used as an aircraft maintenance hangar during that time. Facility 1205 has handled oils,
antifreeze, and solvents from 1957 to the present.
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RI (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RI indicate that 20 groundwater samples were
collected from monitoring wells and 11 groundwater samples were collected from CPT locations
during final sampling rounds. Samples were analyzed for VOCs, petroleum products, and
inorganic constituents. In addition to groundwater sampling, subsurface soil samples were
collected from seven soil borings and six surface soil samples were collected from SD031.
Sample locations, constituents analyzed, and results are presented in the EIOU RI (Weston,
1995a).
Classes of COCs detected in the groundwater at SD031 during the RI include VOCs
and one metal. The VOCs identified as COCs include TCE, benzene, 1,1-DCE, cis-l,2-DCE?
carbon tetrachloride, chloroform, 1,2-DCA, and vinyl chloride. Nickel was identified as a metal
Travis AFB Groundwater 1ROD A-43 as of 3 December"] 997
-------
COC. TPH at concentrations up to 7,000 ug/L was detected in the groundwater at SD031.
According to agreements with agencies during the RJ, TPH was not considered a COC in the
EIOU. TCA was identified in groundwater at SD031 (maximum 12,000 ug/L), but based on
health risk assessments, was not considered a COC. Site location, contaminant concentrations,
and a conceptual site model are presented in Figure A-l 1. Contamination was not found in the
site soils during the RJ.
A.9.2 Feasibility Study
The alternatives evaluated in the FS for SD031 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had scores ranging from 27 to 29. Capital and
first year O&M costs for these three alternatives were $620,000 capital with $128,000 O&M for
Alternative 3; $700,000 capital with $156,000 O&M for Alternative 5; and $2.58 million capital
with $2.4 million O&M for Alternative 7.
A.9.3 Selected Interim Remedial Actions/Objectives
The selected interim action for SD031 is Alternative 3, Extraction, Treatment, and
Discharge of the contaminated groundwater. Concentrations of TCE (greater than 3,000 ug/L)
and other VOCs indicate that DNAPL may be present. Source control will ensure that further
groundwater contamination does not occur.
Travis AFB Groundwater IROD A-44
as of 3 December 1997
-------
A.9.4 Conceptual Site Model
Generator maintenance activities at Facility 1205 may have contributed to fuel-related
contamination in the subsurface. Another possible source is an incinerator which was located
behind the facility in an open field. The exact location of the incinerator has not been confirmed.
Disposal of burned materials from the incinerator may have released contaminants. Although
subsurface contamination was detected during the RI, no COCs were identified in the soil or
other media at SD031 (Weston, 1995a).
Travis AFB Groundwaicr 1ROD A-45 as of 3 DccembeM997
-------
SD031 (Facility 1205)
Primary Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
Metals
Remediation
Driver
Collective
Human Risk
for These
Contaminants
ls
HR = 5.24x10'
Contaminant
of Concern
TCE
Benzene
1.1 -DCE
cis 1,2-DCE
Carbon Tetrachloride
Chloroform
1.2-DCA
Vinyl Chloride
Nickel
Maximum
Reported
Concentration
•8-.1-00>g/L
6.75 nQlL
7,300//g/L
3.
11
4.34j
-------
Conceptual Model
Areas of TCE-
Contaminated
Groundwater (ug/L)
< Site Boundary
/v
Direction of Groundwater Flow
GOO
SCALE IN FEET
Travis AFB Groundwater IROD
-------
A.10 SITE ST032 (AREAS OF MW-107 AND MW-246)
A.10.1 Site Background
Site ST032 covers approximately 22 acres and encompasses the areas around MW-107
and MW-246 in the central part of the EIOU. These MWs are placed in the area of Storm Sewer
System A, which drains the industrial area of the EIOU. Miscellaneous chemical wastes
generated from base shops and waste areas may have been discharged into the storm sewer and
surface drainage systems in this area (Weston, 1995).
The Air Force conducted nine sampling rounds at sites within the EIOU during the RI.
Results from Rounds 1 through 6 were used for preliminary screening of sites and data. Results
from Rounds 7 through 9 were used for risk assessments based on comments from agencies.
Sampling efforts are described in Section 2.0 of the EIOU RI (Weston, 1995a). Summary tables
2.2-1 through 2.2-3 and Appendix A of the RI indicate that four groundwater samples were
collected from the area surrounding MW-107, and four groundwater samples were taken from
the area surrounding MW-246. Samples were analyzed for VOCs, SVOCs, dioxins/furans,
petroleum products, inorganic constituents, and total dissolved solids. In addition to groundwater
sampling, subsurface soil samples were collected from two soil borings in the area surrounding
MW-246. Sample locations, constituents analyzed, and results are presented in the EIOU RI
(Weston, 1995a).
Classes of COCs detected in the groundwater at these MWs during the RI include
VOCs and one SVOC. VOCs identified as COCs include benzene, TCE, 1,1-DCE, and xylenes.
Bis(2-ethylhexyl)phthalate (a SVOC) was also identified as a COC. TPH was present as floating
product and in the groundwater at concentrations up to 29,000,000 |ig/L near MW-246. Based on
the contaminants identified during the RI, groundwater contamination at ST032 is found in two
areas, Plume A and Plume B. Plume A is characterized by VOC and SVOC contamination, and
is located in the MW-107 area. Plume B is characterized by a light aqueous-phase liquid floating
Travis AFB Groundwater IROD A-47 as of 3 DecemberT997
-------
product (LNAPL) and xylene contamination, and is located in the MW-246 area. Site location,
contaminant concentrations, and a conceptual site model are presented in Figure A-12. Soil
contamination found during the RI includes VOCs, PAHs, pesticides, PCBs, and metals.
A.10.2 Feasibility Study
The alternatives evaluated in the FS for ST032 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/cataljtic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), Alternative 7 (extraction, ion exchange, activated
carbon, and discharge), and Alternative 9 (extraction, bioslurping, recovered product recycling,
and off gas catalytic oxidation). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capita] cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 all had scores of 31. Capital and first year
O&M costs for these three alternatives were $2.2 million capital with $177,000 O&M for
Alternative 3; $2.2 million capital with $220,000 O&M for Alternative 5; and $2.0 million
capital with $280,000 O&M for Alternative 7. Alternative 9 had a total score of 25, a capital cost
of $270,000, and first year O&M cost of $17,000.
A. 10.3 Selected Interim Remedial Actions/Objectives
The selected interim action for the groundwater at ST032 (Plume B) is Alternative 3,
Extraction, Treatment, and Discharge. This will be accomplished through source control with
free product removal such as bioslurping, or other free product removal method. Bioslurping
results in groundwater and vapor that requires treatment. Alternative 3 will prevent further
contamination of the groundwater from the free product.
Selection of an alternative for the Plume A groundwater is deferred until the final
Groundwater ROD so that additional data can be collected and evaluated to support the use of
Travis AFB Groundwater IROD A-48 as of 3 DecembeTl997
-------
natural attenuation as a remedial action. Additional site-specific data regarding natural
attenuation will be developed for evaluation as part of the Basewide Natural Attenuation
Assessment Plan. Natural attenuation appears to be a viable alternative for this site as a
cost-effective way to meet CERCLA criteria because of the low TCE concentrations (maximum
64 ug/L), and the plume appears to be stable. In addition, the presence of TPH for cometabolism
and degradation products indicate natural attenuation is occurring.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
A.I0.4 Conceptual Site Model
Contamination in the soils at the site include benzene, TCE, and 1,1-DCE, all of which
are also found in the groundwater. The main source of groundwater contamination appears to be
the floating product. Once this is removed, contaminant concentrations in the soil are expected to
degrade naturally. The potential source of TCE was identified in the RI (Weston, 1995a) as an
upgradient location (SS016). PCBs and metals are also soil COCs but are not identified as
groundwater contaminants.
Travis AFB Groundwater 1ROD A-49 as of 3 December! 997
-------
ST032 (Areas MW-107 and MW-246)
oPrlmar ContamlnantB. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
type
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
Contaminant
of Concern
Collective
Human Risk
for These
Contaminants
Is
HR = 1.5x10"2
Maximum
Reported
Concentration
NA
Floating Petroleum Product (LNAPL)
Banzene 5,
TCE 64,ug/L
1.1 -DCE 0.36 ^g/L
Xylenes 6.702 pglL
Bis(2-ethy1hexyl)phthalate 153^g/L
Site Characteristics
• Grassy, open area between a runway and an abandoned taxiway
• Proximities to runway severely restrict land use (and potential remedial actions)
• 20% of MW-1 07 area covered by runway and taxiway
• 1 0% of MW-246 area covered by runway and taxiway
• TCE in groundwater — iOpglL average, 64//g/L maximum
• TPH in groundwater — 1 5,000,000 ^g/L average, 29,000.000 ^g/L maximum, floating petroleum product is present
• Estimated contaminated groundwater surface area = 220,000 ft* volume = 1 ,000,000 ft3
• Estimated mass of dissolved VOCs equals 1 80 Ib (does not include TPH); LNAPL is present
• Ca, Cr. Cu, Ni, and Ag were measured at concentrations greater than NPDES discharge limits
in some monitoring wells
• Depth to groundwater — 7 feet
• Depth to bedrock — 30 feet
^ Site also studied for sub-surface soil contamination
• Storm sewer system is a potential groundwater/surface water pathway (under investigation)
Selected Interim Remedial Actlon/Ob|ectlvea
• Alternative 3: Extraction, Treatment and Discharge (Plume B)
- Plume B
- Source Control for Floating Petroleum Product Removal
• Selection deferred for Plume A, area will be included in the Basewide Natural Attenuation Assessment Plan
Feasibility Study Treatment Alternatives and Associated Costs
• Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $113,600; First Year O & M = $72,000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 3: Air Stripper/Catalytic Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $2.200,000; First Year O & M = $177,000
- FS Alternative 5: UV Oxidation, Ion Exchange, Activated Carbon,
Capital Cost = $2,160.000; First Year O & M = $220,000
- FS Alternative 7: Ion Exchange. Activated Carbon:
Capital Cost = $2,000,000; First Year O & M = $280,000
- FS Alternative 9: Bioslurping. Recovered Product Recycling, Off-gas Catalytic Oxidation:
Capital Cost = $270,000; Rrst Year 0 & M = $17.000
• These costs derived from the FS will be refined during the remedial design phase
* based on combination of alternatives and site specific variables
Interim Design Assumptions
• Bioslurping/Free Product Removal (Plume B)
• Monitoring Wells (NOTE: Location and number of wells will be
* determined during remedial design phase)
• Determine groundwater/surface water interactions
and design appropriate responses
Figure A-12.
Site Summary Information
for ST032, Travis AFB
A-5 0
SST032.CDR - VMG 9/4/97 SAC t
as of 3 December 1 997
-------
Conceptual Model
Taxlway H
Runway
Taxlway R
1 Fuel Line Leak
(specific location unknown)
Floating
Petroleum
Product
roimdwaterl'
Extent of Soil
Contamination
Natural Attaouanon Evaluation
Extent of TPH in Ground water
Site Boundary s
Bioslurplng/Floating Petroleum
' Product Removal
Existing Monitoring Wells
Indicates Approximate Direction
of Groundwater Flow
Storm Sewer A o iso aoo MO
— — Storm Sewer
Travis AFB Groundwater IROD
-------
A.11 SITE SD033 (STORM SEWER SYSTEM II/FACILITIES 810 AND 1917,
SOUTH GATE AREA, AND WEST BRANCH OF UNION CREEK)
A.ll.l Site Background
Site SD033, which covers a total of approximately 24 acres, is located in the West
Industrial Operable Unit (WIOU), encompasses parts of Storm Sewer System II (previously
called Storm Sewer System B), Facilities 810 and 1917, the area around the South Gate, and the
west branch of Union Creek. Storm Sewer System II, comprised of underground piping, and the
West Branch of Union Creek collect runoff from within the WIOU and small portions of the
EIOU and West Annexes and Basewide Operable Unit (WABOU). Runoff from Storm Sewer II
generally flows south and enters Union Creek south of the WIOU in the EIOU. Dissolved
contamination in the groundwater at SD033 migrated from broken or damaged areas of the storm
sewer and underground piping.
Facility 810, constructed in 1955, is used for aircraft refurbishing activities. An OWS,
sump, and wash rack previously existed at the facility and discharged to Storm Sewer System II.
This equipment has been abandoned, and the facility no longer discharges to the storm sewer.
Wastes generated at the facility in the past have included PD-680, paints, solvents, lubricants,
PCBs, and fuels.
Facility 1917 is located south of Facility 810 just west of the flightline apron and was
constructed in 1956 for use as an aircraft washdown area (Radian, 1996b). An OWS and
wastewater collection sumps, previously used during washdown activities, remain at the facility
but are no longer in use. Wastes generated at the facility during past activities include PD-680,
soaps, engine oil, hydraulic fluid, and jet fuel.
The Air Force collected groundwater samples from 32 locations at SD033 during the
RI. At Facility 810, 10 CPT HydroPunch® samples and 2 monitoring well samples were
Travis AFB Groundwater IROD A-51 as of 3 DecembeTl997
-------
collected; at Facility 1917, 2 monitoring wells were sampled; along Storm Sewer System II 10
CPT HydroPunch samples and 2 monitoring well samples were collected; and at the South Gate
area, 6 CPT HydroPunch® samples were collected. Groundwater samples were analyzed for
petroleum hydrocarbons, inorganic constituents, pesticides and PCBs, VOCs, and SVOCs
(Radian, 1996b). In addition to groundwater sampling, surface water, sediment, and surface soil
samples were collected from 10 transect locations in SD033, 16 soil borings were drilled for
subsurface investigations, 2 surface flux samples were collected, and video surveying was
performed to inspect the quality of the storm sewer. Specific sampling locations, constituents
analyzed, and results can be obtained in the WIOU RI (Radian, 1996b).
Classes of COCs identified in the groundwater at the site during the RI include VOCs
and one SVOC. VOCs identified as COCs include TCE, 1,1 -DCE, 1,2-DCA, cis-l,2-DCE, and
TPH-gasoline (TPH-G). TPH-extractable (TPH-E) was identified as a SVOC COC. Site location,
contaminant concentrations, and a conceptual site model are presented in Figure A-13.
Contaminants identified in other media at SD033 include: VOCs in the soil gas and sediment;
SVOCs in the sediment; and metals in the sediment, surface soil, and surface water.
A.11.2 Feasibility Study
The alternatives evaluated in the FS for SD033 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had scores ranging from 27 to 31. Capital and
first year O&M costs for these three alternatives were $2.6 million capital with $180,000 O&M
for Alternative 3; $2.7 million capital with $230,000 O&M for Alternative 5; and $2.3 million
capital with $140,000 O&M for Alternative 7.
Travis AFB Groundwater IROD A-52 as of 3 December"]997
-------
A.I 13 Selected Interim Remedial Actions/Objectives
The selected interim action for SD033 is a combination of Alternative 3 for the Storm
Sewer area of contamination and Alternative 2, Natural Attenuation with groundwater
monitoring, for the remainder of the site. Alternative 3 using migration control is needed for
Storm Sewer II because of VOC concentrations (up to 1,000 jig/L) in the groundwater and
possible hydraulic connections with subsurface utilities that could lead to further contaminant
migration (see also Figure 3-6).
Selection of an alternative for the South Gate, Facility 1917, and Facility 810 plumes
has been deferred until the final Groundwater ROD. This will allow site-specific data to be
collected and evaluated to support the use of natural attenuation as a remedial action. Natural
attenuation appears to be a viable alternative because contaminant concentrations are relatively
low and only appear in small isolated areas near the South Gate and Facilities 810 and 1917. The
remainder of the plumes also appear relatively stable. Additional data regarding natural
attenuation will be developed for evaluation as part of the Basewide Natural Attenuation
Assessment Plan.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
Travis AFB Groundwater IROD A-53 as of 3 DecemberT997
-------
A.I 1.4 Conceptual Site Model
Sources of groundwater contamination at SD033 include the storm sewer pipeline for
the storm sewer portion, and the OWS, wash rack, and storm sewer pipeline for Facility 810
plume. Contaminants found in the sediments, surface soils, and surface water at SD033 are not
related to contaminants detected in the groundwater. Some VOCs identified in the soil gas were
also found in the groundwater, including TCE, cis-l,2-DCE, and TPH-G; however, they are not
considered to be a source of groundwater contamination.
Travis AFB Groundwater IROD A-54 as of 3 DecembeTl997
-------
SD033 (Storm Sewer System Il/Facilities; 810 and 1917,
South Gate Area, and West Branch of Union Creek)
Primary Contaminants. Remediation Drivers and Affected Media
* Maximum
Contaminant Remediation Contaminant Reported
Medium Type Driver of Concern Concentration
Groundwater VOCs HR = 3.6x10'5 TCE 941 ng/L
» Groundwater VOCs HR=1.7x10'6 1,1-DCE 0.42,«g/L
Groundwater VOCs Exceeds MCL 1,2-DCA 1.36^
-------
Conceptual Model
Subsurface Soil Contamination
(Ecological Risk)
Facility 81OTCE
Concentration
Contours («g/L)
(Max200^g/L)
Surface Soil Contamination
(Ecological Risk)
Treatment Plant
i ^TiP-
Discharge Piping
I "Irfl • r\
Untreated Water
Facility 1917 Plume
(TCE2.3jug/Land
cls-1,2-DCE
15.7 ^g/L)
Subsurface Soil
Contamination
Storm Sewer TCE
Concentration
Contours (ug/L)
(Max720/zg/L)
Horizontal Well
TPHin
Groundwater
South Gate Plume
TCE in Groundwater
Existing Monitoring Wells
Indicates Approximate
Direction of Groundwater Row
0 250 500 1000
SCALE IN FEET
— —• Storm Sewer System
Travis AFB Groundwater I ROD
-------
A.12 SITE SD034 (FACILITY 811)
A.12.1 Site Background
Site SD034 covers approximately 1.1 acre and encompasses Facility 811, located in the
northern portion of the WIOU on Ragsdale Street south of Hangar Avenue. The Facility includes
an indoor wash rack, installed in 1979, which is used to wash, strip, and pretreat aircraft parts
prior to painting. Wastewater from the wash rack flows into an OWS. Flow from the OWS can
be directed into either the sanitary sewer or a concrete-lined overflow pond located just west of
the facility. A hole was discovered in the OWS during 1994. The defective OWS was removed
and replaced with the current OWS. Chemicals used at this facility include acids, solvents,
antifreeze, and the Stoddard solvent PD-680.
The Air Force collected groundwater samples from 14 locations in the area of Facility
811 during the RI. Samples were collected from soil borings, monitoring wells, and CPT
locations. Samples were analyzed for petroleum hydrocarbons, inorganic constituents, pesticides
and PCBs, VOCs, and SVOCs. In addition to groundwater samples, 2 surface soil samples,
23 soil gas samples, and 14 subsurface soil samples were collected at SD034. Sampling
locations, constituents analyzed, and results can be obtained in the WIOU RI (Radian, 1996b).
Classes of COCs detected in the groundwater during the RI include VOCs and SVOCs.
VOCs identified as COCs include TCE, vinyl chloride, 1,1 -DCE, benzene, cis-l,2-DCE, PCE,
and TPH-G. TPH-E and bis(2-ethylhexyl)phthalate were identified as SVOC COCs. A floating
product layer of PD-680, a light non-aqueous phase liquid (LNAPL), is also present at the site
and is considered a COC. Site location, contaminant concentrations, and a conceptual site model
are presented in Figure A-14. Additional contaminants detected include TPH-G and TPH-E in
the soil, and TCE, PCE, and cis-l,2-DCE in the soil gas (Radian, 1996b).
Travis AFB Groundwaler 1ROD A-56 as of 3 DecembeTl997
-------
A.12.2 Feasibility Study
The alternatives evaluated in the FS for SD034 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), Alternative 7 (extraction, ion exchange, activated
carbon, and discharge) and Alternative 9 (extraction, bioslurping, recovered product recycling,
and off gas catalytic oxidation). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 all had scores of 31. Capital and first year
O&M costs for these three alternatives were $490,000 capital with $86,000 O&M for
Alternative 3; $570,000 capital with $110,000 O&M for Alternative 5; and $380,000 capital with
$79,000 O&M for Alternative 7. Alternative 9 had a total score of 25, capital cost of $270,000,
and a first year O&M cost of $3,900.
A.12.3 Selected Interim Remedial Actions/Objectives
The selected interim action for SD034 is Alternative 3, Extraction, Treatment, and
Discharge, with both source and migration control. Source control will involve removal of the
floating free product (PD-680) through bioslurping or other free product removal method.
Migration control will be achieved by groundwater extraction and will be coordinated with
interim actions for SD037.
Alternative 3, using source and migration control, was selected at this site due to the
potential for contaminants to migrate to the West Branch of Union Creek (located approximately
150 feet west of SD034). Removal of the free product will eliminate further contamination of the
groundwater, and migration control will ensure that contaminants do not migrate further from the
site.
Travis AFB Groundwater 1ROD A-57 asof 3 December! 997
-------
A.12.4 Conceptual Site Model
Sources of groundwater contamination include leaks from the OWS and associated
piping at Facility 811. Contaminants, particularly chlorinated hydrocarbons, are commingled
with groundwater contamination at SD037. Contamination detected in the soils at the site include
TPH-G and TPH-E which are also present in the groundwater. Soils contamination could be a
source of contaminants found in the groundwater but should naturally attenuate and not impact
groundwater once the floating product (PD-680) is removed.
A. 12.5 Special Site Considerations
SD034 and SD037 plumes are commingled; interim remedial actions will be
coordinated to ensure that the extraction system is optimized, and the most cost effective interim
remedial action is design and implemented.
Travis AFB Groundwater IROD A-58 as of 3 December"!997
-------
SD034 (Facility 811)
Prlmarv Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
SVOCs
Remediation
Driver
NA
HR = 3.0x10'5
HR = 3.1 x 1CT5
HR= 1.2x10'6
Exceeds MCL
Exceeds MCL
HR= 1.2 x10'5
NA
NA
HR = 3.3x10'4
Contaminant
of Concern
LNAPL (PD-680)
TCE
Vin/l Chloride
..1 DCE
Benzene
cis-1,2-DCE
PCE
TPH-gasoline
TPH-E
bis(2-ethylhexyl)phthalate
Maximum
Reported
Concentration
-1 foot thick
740 fig/L
0.31 7 uglL
6.8 fig/L
496/g/L average, 740 figfL maximum
• TPH in groundwater — 5,000,000uglL average, 13,000,000 /
-------
Conceptual Model
Overflow Pond
V -; "I
.Water Table V .^.^
*•-••»•«' «^lt'n;-
Groundwater Contamination
Oil/Water
Separator
North
51_
Bioslurping/
Free Product
SD037 Groundwater | Removal
Contamination
SD034 PD-6BO Floating Product
Soil Contamination
(TPH)
TCE Concentration
Contours (NO)
Existing Monitoring Wells
Indicates Approximate
Direction of Groundwater Flow
...M^.~.»>. .-^^^.a^^M-
Travis AFB Groundwater IROD
-------
A.13 SITE SS035 (FACILITIES 818/819)
A.13.1 Site Background
•
Site SS035 covers approximately 5 acres and consists of Facilities 818 and 819, located
in the northern part of the WIOU. Facility 818, constructed in 1970, is used to repair, wash, and
paint aircraft. Wash water at the facility flows into trench drains and then into an OWS which
discharges to the sanitary sewer system. Facility 819 contains an electro-environmental shop, a
wheel and tire shop, and a hazardous waste accumulation area. Chemicals used at these facilities
include lubricating oil, hydraulic fluids, PD-680, and water solutions of these chemicals.
The Air Force collected 10 HydroPunch* groundwater samples from soil borings at
SS035 during the RI. Samples were analyzed for petroleum hydrocarbons, inorganic constituents,
pesticides and PCBs, VOCs, and SVOCs. In addition to groundwater sampling, 56 soil samples
and 20 soil gas samples were collected. Sampling locations, constituents analyzed, and results
can be obtained in the WIOU RI (Radian, 1996b).
COCs detected in the groundwater during the RI include one VOC and one SVOC:
TCE and TPH-E, respectively. Site location, contaminant concentrations, and a conceptual site
model are presented in Figure A-15. Other contaminants detected include PCBs and metals in the
surface soil, and TCE and vinyl chloride in the soil gas. A contaminant source could not be
determined for the PCBs (Radian, 1996b).
A.13.2 Feasibility Study
The alternatives evaluated in the FS for SS035 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 4 (extraction, air stripper/catalytic
oxidation, activated carbon, and discharge), Alternative 6 (extraction, UV-OX, activated carbon,
and discharge), and Alternative 8 (extraction, activated carbon, and discharge). As evaluated in
Travis AFB Groundwaier IROD A-60 as of 3 DecemberT997
-------
the FS, Alternative 1 had the lowest cost, but the lowest total score. Alternative 2 had a capital
cost of $18,600, a first year O&M cost of $72,000, and a total score of 16. Alternatives 4, 6, and
8 all had scores of 33. Capital and first year O&M costs for these three alternatives were
$310,000 capital with $77,000 O&M for Alternative 4; $376,000 capital with $100,000 O&M for
Alternative 6; and $190,000 capital with $100,000 O&M for Alternative 8.
A.13.3 Selected Interim Remedial Actions/Objectives
Selection of an alternative is deferred for the groundwater at SS035 until the final
Groundwater ROD. This will allow site-specific data to be collected and evaluated to support the
use of natural attenuation as a remedial action. Natural attenuation appears to be a viable
alternative for this site because the area of contamination appears to be stable, TCE
concentrations in groundwater are low (average of 5 ug/L) and the areal extent is limited. In
addition, TPH is present for cometabolism and TCE degradation by-products were detected
indicating that natural attenuation is occurring. Additional data regarding natural attenuation will
be developed for evaluation as part of the Basewide Natural Attenuation Assessment Plan.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
Travis AFB Groundwater IROD A-61 as of 3 DecembeTl997
-------
A.13.4 Conceptual Site Model
The probable source of the groundwater contamination was identified as the OWS
associated with Facility 818. Surface soil contamination, including PCBs, was identified at
SS035 during the RI. The soil contamination is located near Building 818 and is not related to
the groundwater contamination. Remediation of the surface soils is not expected to affect
groundwater.
Travis AFB Groundwater IROD A-62 as of 3 December 1997
-------
SS035 (Facility 818/819)
Primary Contaminants. Remediation Drivers and Affegted Manila
Maximum
Contaminant Remediation Contaminant Reported
Medium Type Driver of Concern Concentration
Groundwater VOCs Exceeds MCL TCE 21 uglL
^ Groundwater SVOCs Exceeds Standard TPH-E 160^9/L
Site Characteristics
• Asphalt and roadbase covers most of the site
• Facility 818/819 includes a wash area, oil/water separator and si mp,
hydraulic lift storage area, and hazardous material accumulation area
• TCE in groundwater — 5^g/L average, 21 ftg/L maximum
• Estimated mass of dissolved VOCs equals 0.007 Ib, estimated plume volume equals 12,000 ft*;
no evidence of DNAPL or LNAPL
• Depth to groundwater — 15 feet
• Low permeability soils (clay and silt) to about 15 feet bgs
• More permeable material (sand lens) encountered throughout site
• Site also studied for surface soil contamination
Selected Interim Remedial Action/Objectives
• Deferred: Site will be included in the Basewide Natural Attenuation Assessment Plan
Feasibility Study Treatment Alternatives and Associated Costs
• Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $18.600; First Year O & M = $72.000
^ Alternative 3: Extraction, Treatment and Discharge
B- FS Alternative 4: Air Stripper/Catalytic Oxidation, Activated Carbon:
W Capital Cost = $310.000; First Year O & M = $77,000
- FS Alternative 6: UV Oxidation, Activated Carbon:
Capital Cost = $376.000; First Year O & M = $100,000
- FS Alternative 8: Activated Carbon:
Capital Cost = $190,000; First Year O & M = $100,000
• These costs derived from the FS will be refined during the remedial design phase
based on combination of alternatives and site specific variables
Figure A-15.
Site Summary Information
for SS035, Travis AFB
SSS03S.COR - VMG 9/4/97 SAC 1
A-63 as of 3 December 1997
-------
Conceptual Model
TCE Concentration Contours (ug/L)
in Groundwater
Areas of Soil
Contaminated
with PCBs
(Human Health Risk)
o Existing Monitoring Wells
— Storm Sewer System
Indicates Approximate
Direction of Groundwater Row
Travis AFB Groundwater IROD
-------
A.14 SITE SD036 (FACILITIES 872/873/876)
A.14.1 Site Background
Site SD036, located in the western portion of the WIOU, covers approximately 6 acres,
and is comprised of Facilities 872, 873, and 876. The three facilities were constructed in 1953 as
multiple use shops for Civil Engineering (CE). Facility 872 is currently used for maintenance and
storage of CE vehicles and landscaping equipment. An OWS previously located at the facility
was removed in 1994. Facility 873 contains the CE interior electric, locksmith, and paint shop.
Facility 876 is used for paint mixing. An accumulation area for waste paints and thinner is
adjacent to the facility. Chemicals used at this site include cleaning solutions, grease, degreasers,
hydraulic oils and fluids, PD-680, pesticides, paints, and solvents.
The Air Force sampled groundwater from 25 locations at SD036 during the RJ.
Samples were collected from soil borings, CPT locations, and groundwater monitoring wells.
Groundwater samples were analyzed for petroleum hydrocarbons, inorganic constituents,
pesticides and PCBs, VOCs, and SVOCs. In addition to groundwater sampling, 36 soil gas
samples and 31 soil samples were collected at SD036. Sampling locations, constituents analyzed,
and results can be obtained in the WIOU RI (Radian, 1996b).
Classes of COCs detected in the groundwater at SD036 during the RI include VOCs
and one SVOC. VOCs identified as COCs include vinyl chloride, TCE, 1,1-DCE, cis-l,2-DCE,
1,2-DCA, benzene, bromodichloromethane, PCE, and TPH-G. TPH-E was identified as a SVOC
COC. Site location, groundwater contaminant concentrations, and a conceptual site model are
presented in Figure A-16. Additional contamination detected during the RI includes several
VOCs in the soil and soil gas, and SVOCs in the soil gas (Radian, 1996b).
Travis AFB Groundwater IROD A-64 as of 3 December J997
-------
A natural attenuation study will be conducted at SD036 to evaluate the feasibility of
natural attenuation of chlorinated solvents using a technical protocol jointly developed by
AFCEE and U.S. EPA.
A.14.2 Feasibility Study
The alternatives evaluated in the FS for SD036 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 1 had the lowest cost, but
also the lowest total score. Alternative 2 had a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3,5, and 7 had scores ranging from 27 to 31. Capital and
first year O&M costs for these three alternatives were $795,000 capital with $110,000 O&M for
Alternative 3; $860,000 capital with $144,000 O&M for Alternative 5; and $2.3 million capital
with $1.9 million O&M for Alternative 7.
A.14.3 Selected Interim Remedial Actions/Objectives
The selected interim action for groundwater at SD036 is Alternative 3, Extraction,
Treatment, and Discharge using source and migration control. Source control is necessary to
address cis-1,2-DCE concentrations greater than 3,000 |ig/L. Prior to the design and installation
of the extraction system, the site will be evaluated for natural attenuation. Results of this natural
attenuation study will be used to assess the need for an active extraction interim action.
A. 14.4 Conceptual Site Model
Sources of groundwater contamination at Facilities 872, 873, and 876 include the OWS
and wash rack at Facility 872 as well as the hazardous waste storage area at Facilities 873
Travis AFB Groundwater IROD A-65 as of 3 Decembef 1997
-------
and 876 (Radian, 1996b). Contaminants in the soil gas at SD036 includes TCE, vinyl chloride,
1,1-DCE, cis-l,2-DCE, benzene, PCE, and TPH-G, and were used to determine soil and
groundwater sampling locations for the RI. Contaminants in the soil include TPH-G and TPH-E.
Because these contaminants are also present in the groundwater, they may contribute to
contamination in the soil. Any activities conducted to remediate the groundwater could have an
effect on the soil.
A. 14.5 Special Site Considerations
At SD036 a natural attenuation study is being performed by AFCEE. This study will
evaluate the site using natural attenuation protocol developed by U.S. EPA and AFCEE. The
migration and source control actions selected for this site will be deferred until results of the
study are reviewed, estimated to be late 1998. Based on the results, the migration control and
source control actions will be implemented or reevaluated.
Travis AFB Groundwater IROD A-66 as of 3 December 1997
-------
SD036 (Facilities 872/873/876)
Primary Contaminants. Remediation Drivers and Affected Media
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
Remediation
Driver
HR = 2.1 x 10'3
HR = 2.4 x 10'5
HR = 2.2x10'5
HI = 6.2
Exceeds MCL
HR= 1.2X1CT6
HR= 1.0X10"6
HR= 1.6X10"4
NA
NA
Contaminant
of Concern
Vinyl Chloride
TCE
1 1-DCE
cis-1.2-DCE
1 2-DCA
Benzene
Bromodiohloromethane
PCE
TPH- gasoline
"PH-E
Maximum
Reported
Concentration
3.71
3.
3.87 jug/L
2.26 ftg/L
382 ng/L
4.380 ftg/L
480 ^g/L
Site Characteristics
• The site is paved with two to four feet of asphalt and road base material and is surrounded by buildings
• The site is active
• Site is adjacent to SD037 — groundwater plumes are mixed
• TCE and cis-1,2-DCE in groundwater — 2,900 ftg/L average TCE and DCE, 3,870/ug/L maximum cis-1,2-DCE
• Estimated contaminated groundwater surface area = 153,000 ft^ volume = 610,000 ft3
• Estimated mass of dissolved VOCs equals 140 Ib; ONAPL may be present
• Cu and Hg were measured at concentrations greater than NPDES discharge limits
in some monitoring wells
• Depth to groundwater—10 feet; depth to bedrock —> 30 feet
• Low permeability alluvium (clay) from 4 to 9.5 feet bgs, and moderate permeability alluvium
(clayey sand) from 8 to 18 feet bgs
• Thick, discontinuous sand units
• Site also studied for soil contamination
Selected Interim Remedial Action/Objectives
• Alternative 2: Natural Attenuation/Monitoring
- Based on completed Natural Attenuation Study
- Migration Control (TCE) depending on results of Natural Attenuation Study
- Alternative 3: Extraction, Treatment and Discharge
- Source Control (DCE) depending on results of Natural Attenuation Study
Feasibility Study Treatment Alternatives and Associated Costs
• Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $18,600; First Year O & M = $72.000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 3: Air Stripper/Catalytic Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $795,000; First Year O & M = $110,000
- FS Alternative 5: UV Oxidation. Ion Exchange, Activated Carbor:
Capital Cost = $860,000; First Year O & M = $144,000
- FS Alternative 7: Ion Exchange, Activated Carbon:
Capital Cost = $2.300,000; First Year O & M = $1.900.000
These costs derived from FS will be refined during the remedial design phase
based on combination of alternatives and site specific variables
Interim Design Assumptions
• 2 horizontal wells, 300 feet in screened length each
(NOTE: Location and number of wells will be determined _
during the remedial design phase)
• Extraction rate 30 gpm total, 15 gpm from each well
• 550 feet of untreated water piping
(from well to treatment system) — 1 inch ID. sch 80 PVC
- 70 feet of discharge piping (to west branch of Union Creek) —
2 inch ID. sch 80 PVC
• 70 feet from treatment system to existing power line
Figure A-16.
Site Summary Information
for SD036, Travis AFB
5SOO36 COR • VMG 8/19/9? SAC 1
A-67
as of 3 December 1997
-------
Conceptual Model
TPHIn
Ground water
Treatment
System
II
Discharge
Piping
Soil Contamination
(TPH)
Horizontal Well
{Source Control) Jt]fl_
Site Boundary
Untreated Water Piping
1() ^ fTypical)
Horizontal Well
(Migration Control)
SD037
Groundwater
Contamination
VOC Concentration
Contours fag/L)
Existing Monitoring Wells
Indicates Approximate
Direction of Groundwater Row
Travis AFB Groundwater IROD
-------
A.15 SITE SD037 (SANITARY SEWER SYSTEM, FACILITIES 837, 838, 919, 977,
AND 981, AREA G RAMP, AND RAGSDALE/V AREA)
A. 15.1 Site Background
Site SD037 covers approximately 90 acres and encompasses a large portion of the
WIOU including the Sanitary Sewer System, Facilities 837, 838, 919, 977, and 981, the Area G
Ramp, and the Ragsdale/V Area. The portion of the Sanitary Sewer System encompassed by this
site includes approximately 22,000 feet of underground piping, which is used to deliver domestic
and industrial wastewater from facilities within the WIOU, to the Fairfield-Suisun publicly-
owned treatment works. Dissolved contamination in the groundwater at SD037 migrated from
broken or damaged areas of the sanitary sewer system.
Facilities 837 and 838 were constructed in 1954 and used for aircraft maintenance.
They are currently used as office buildings. Both facilities contain a sump that has been
abandoned in place and a transformer that formerly contained PCBs. Facility 919, constructed in
1984, is used to maintain heavy equipment and contains an OWS which discharges to the
sanitary sewer. A wash rack and hazardous waste accumulation area are located east of the
facility. Facility 977, constructed in 1972, is used as an air terminal where personnel use
hydraulic equipment to load and unload cargo. In the past, leaks were reported from the hydraulic
rams (Radian, 1996b). These rams have since been replaced and are now periodically checked for
leaks. Facility 981, located northeast of Facility 977, was constructed in 1975. A waste
accumulation area was located northeast of the facility, and a vehicle wash area was located east
of the facility.
The Area G Ramp, located just south of Facility 977, contains a hydrant system used
for fueling aircraft. The hydrant system consists of a pressurized fuel pipeline and aircraft fueling
spots, each with a riser pipe which can be attached to a pump truck. The Ragsdale/V Area
Travis AFB Groundwater IROD A-68 as of 3 Decembe? 1997
-------
encompasses an open grassy area at the intersection of Ragsdale and V streets which contains a
jet fuel distribution piping system.
Chemicals used and handled in these areas include wastewater, oils, hydraulic fluids,
fuels, transformer fluids, and chlorinated solvents.
During the Rl, groundwater samples were collected from 128 locations at SD037:
• 6 HydroPunch* samples were collected from the Area G Ramp;
• 6 HydroPunch* samples and 1 monitoring well sample were collected from the
vicinity of Facility 981;
• 4 groundwater samples were collected from the vicinity of Facility 977; and
• 111 groundwater samples (87 HydroPunch* samples and 24 monitoring well
samples) were collected along the Sanitary Sewer System, which includes the
Ragsdale/V area and the vicinity of Facilities 837, 838, and 919. Groundwater
samples were analyzed for petroleum products, inorganic constituents,
pesticides and PCBs, VOCs, and SVOCs (Radian, 1996b).
In addition to groundwater samples, subsurface soil, surface water, surface emission
flux, sediment, and surface soil samples were collected at SD037:
• At Facility 977, 4 soil samples were collected;
• At Facility 981, 1 surface water sample, 1 sediment sample, 7 surface soil
samples, 12 soil gas samples, and 12 subsurface soil samples were collected;
• At the Area G Ramp, 5 soil samples and 12 soil gas samples were collected; and
• Along the Sanitary Sewer System (including Facilities 919, 837, and 838),
63 soil samples and 7 surface emission flux samples were collected.
Travis AFB Groundwater IROD A-69 as of 3 DecembeTl997
-------
Sampling locations, constituents analyzed, and results can be obtained in the WIOU Rl (Radian,
1996b).
Classes of COCs detected in the ground water at SD037 during the RI include VOCs
and SVOCs. VOCs identified as COCs include 1,1 -DCE, 1,2-DCA, benzene,
bromodichloromethane, carbon tetrachloride, chloromethane, PCE, TCE, vinyl chloride,
cis-l,2-DCE, and TPH-G. SVOCs identified as COCs include bis(2-ethylhexyl)phthalate,
naphthalene, and TPH-E. Site location, contaminant concentrations, and a conceptual site model
are presented in Figure A-17.
Contaminants of concern detected in the subsurface soils include VOCs, petroleum
hydrocarbons, and SVOCs. Metals were identified at isolated locations in the surface soil.
A.15.2 Feasibility Study
The alternatives evaluated in the FS for SD037 were Alternative 1 (no action),
Alternative 2 (natural attenuation and monitoring), Alternative 3 (extraction, air stripper/catalytic
oxidation, ion exchange, activated carbon, and discharge), Alternative 5 (extraction, UV-OX, ion
exchange, activated carbon, and discharge), and Alternative 7 (extraction, ion exchange,
activated carbon, and discharge). As evaluated in the FS, Alternative 3 had the lowest cost, but
also the lowest total score. Alternative 2 has a capital cost of $18,600, a first year O&M cost of
$72,000, and a score of 16. Alternatives 3, 5, and 7 had similar scores ranging from 27 to 29.
Capital and first year O&M costs for these three alternatives were $2.6 million capital with
$210,000 O&M for Alternative 3; $2.7 million capital with $260,000 O&M for Alternative 5;
and $3.2 million capital with $1.3 million O&M for Alternative 7.
Travis AFB Groundwaler 1 ROD A-70 as of 3 DecembeTl997
-------
A. 15.3 Selected Interim Remedial Actions/Objectives
The selected interim action for groundwater at SD037 includes a combination of
Alternative 3, Extraction, Treatment, and Discharge using source and migration control, and
Alternative 2, Natural Attenuation with groundwater monitoring. Source control will be done in
one area near Facilities 837 and 838, and migration control will be done in four areas north and
south of these facilities. Natural attenuation will be used in other areas of the site with low
contaminant concentrations, and the plume appears to be stable.
Source control is selected in areas where a DNAPL is suspected because TCE
concentrations are greater than or equal to 3,000 ug/L. Migration control is required in areas
where contaminants have the greatest potential to discharge to the West Branch of Union Creek.
Selection of an alternative is deferred for the remainder of the plume until the final
Groundwater ROD. This will allow site-specific data to be collected and evaluated in support of
using natural attenuation as a remedial action. Natural attenuation appears to be a viable
alternative because concentrations are low, and the area is paved, limiting the infiltration of water
which could mobilize contaminants and present an impervious barrier to potential human and
ecological receptors. Additional data regarding natural attenuation will be developed for
evaluation as part of the Basewide Natural Attenuation Assessment Plan.
The interface between the storm sewer and contaminated groundwater will be
investigated during the RD (see Figure 3-6). At locations where the contaminated groundwater is
found to be migrating to the storm sewer or creek, an interim remedial action, such as pump and
treat, will be used to control significant migration. Where pump and treat is used, the
effectiveness of this action will be monitored and if it is found that the pump and treat action is
not adequately controlling the migration, a contingency action, such as repair or lining of the
storm sewer will be initiated.
Travis AFB Groundwater IROD A-71 as of 3 December" 1997
-------
A.15.4 Conceptual Site Model
The vehicle wash area at Facility 981 was a source of groundwater contamination.
Hazardous waste and surface spill areas where oily rags, waste oil, and vehicle wash wastewater
are potentially released contributed to contamination. The jet fuel distribution pipeline at the
Area G Ramp was a source of groundwater contamination. Hydraulic equipment at Facility 977,
which may have released hydraulic fluids and oils, contributed to groundwater contamination at
SD037. The Sanitary Sewer System and OWSs and wash racks connected to it was a source of
groundwater contamination. Antifreeze, contaminated gasoline and diesel, transmission fluid,
and waste oil were potentially released from heavy equipment maintenance operations at Facility
919. Transformer fluid was potentially released from OWSs and sumps, USTs, hazardous waste
storage, and surface spill areas near Facilities 837 and 838.
Surface soil and subsurface soil contamination have also been identified in several
locations within SD037. The soil contamination includes VOCs, SVOCs, and metals. The
surface soil contaminants have not impacted groundwater, and any soil cleanup action would
probably not affect groundwater. There are several locations of TPH contamination in the soil,
some of which may be related to groundwater contamination (that is, groundwater directly
underneath the contaminated soil has similar contamination). Soil contamination in these areas
will be addressed using natural attenuation.
A.15.5 Special Site Considerations
The SD034 plume and a portion of the SD037 plume are commingled; interim remedial
actions will be coordinated to ensure that the extraction system is optimized, and the most cost
effective interim remedial action is design and implemented.
Travis AFB Groundwater IROD A-72 as of 3 December 1997
-------
SD037 (Sanitary Sewer System, Facilities 837, 838, 919,
977 and 981, Area G Ramp and Ragsdalo/V Area)
Primary Contaminants. Remediation Drivers and Affected Med a
Medium
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Contaminant
Type
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
VOCs
SVOCs
SVOCs
SVOCs
Remediation
Driver
HR= 1.1 x10*
Exceeds MCL
HR = 1.9x10'
Exceeds MCL
Exceeds MCL
HR= 1.3x10*
HR = 4.6x 10-
HR =5.4x10'
HR = 6.0x104
Exceeds MCL
NA
HR= 1.4x10*
Exceeds MCL
NA
Contaminant
of Concern
1.1 -DCE
1 ,2-DCA
Benzene
Bromodi :hloromethane
Carbon Tetrachloride
Chlo'omethane
PCE
TCE
Vinyl Chloride
cis-1 ,2-DCE
TPH-Gasoline
bis(2-ethy hexyl)phthalate
Napthalene
TPH-E
Maximum
Reported
Concentration
0.598 ftg/L
0.597 ^g/L
14^g/L
0.69 uglL
60.7 ftg/L
1.03^9/L
407 HQIL
6,990 HQIL
60.2 HQIL
340 fiQ/L
4.160/*g/L
139^g/L
115^g/L
2,660,000 nQlL
Site Characteristics
The sanitary sewer system includes approximately 22,000 feet ol piping, as well as associated
oil water separators, sumps, and wash racks
TCE in groundwater — 1,220/jg/L average, 6,990 ftg/L maximum
• Estimated contaminated groundwater surface area = 1,100,000 /f, volume = 4,500,000 ff
• Estimated mass of dissolved VOCs equals 390 Ib, estimated plume volume equals 4,500,000 ff; DNAPL may be present
• Copper and silver were measured at concentrations greater than NPDES levels in some monitoring wells
Depth to groundwater — 10 feet, depth to bedrock — 30 feet
Subsurface geology beneath the sanitary sewer system varies
In general, low permeability alluvium underlies the area with discontinuous permeable layers
I Weathered sandstone and shale interbed to form bedrock layer beneath the alluvium
• Site also studied for surface and sub-surface soil contamination
• Storm sewer is a potential groundwater/surface water pathway
Selected Interim Remedial Actlon/Obfectlves
• Alternative 3: Extraction, Treatment and Discharge
- Source Control (Facility 837/838 and Ragsdale/V Areas)
- Migration Control
• Selection is deferred for remainder of site (southern end), area will be included in the
Basewide Natural Attenuation Assessment Plan
Feasibility Study Treatment Alternatives and Associated Coats
Alternative 2: Natural Attenuation/Monitoring: Capital Cost = $1H,600; First Year 0 & M = $72,000
• Alternative 3: Extraction, Treatment and Discharge
- FS Alternative 3: Air Stripper/Catalytic Oxidation, Ion Exchange, Activated Carbon:
Capital Cost = $2,600,000; First Year O & M = $210,000
- FS Alternative 5: UV Oxidation, Ion Exchange. Activated Carbon:
Capital Cost = $2,700,000; First Year O & M = $260,000
- FS Alternative 7: Ion Exchange, Activated Carbon:
Capital Cost = $3,200.000; First Year O & M = $1.300.000
• These costs derived from the FS will be refined during the remedial design phase based on combination of alternatives
Interim Design Assumptions
5 horizontal wells, 300 feet in screened length
(NOTE: Location and number of wells will be determined during remedial design phase)
Extraction rate 75 gpm total, 15 gpm from each well
4,000 feet of untreated water piping
(from well to treatment system) — 1 inch ID. sen 80 PVC
• 50 feet of discharge piping
(to west branch of Union Creek) — 3 inch ID, sch 80 PVC
100 feet from treatment system to existing power line
Determine groundwater/surface water interactions,
and design appropriate response
Figure A-17.
Site Summary Information
for SD037, Travis AFB
A-73
SSD037.CDR • VUG 8/4/87 SAC t
as of 3 December 1997
-------
Conceptual Model
Alliivlum
TCE Concentration Contours
In Groundwater
Horizontal Well for Migration Control
'/-£
SD034
Untreated Water Piping -
fTypical)
Treatment System
Horizontal Wells
for Source Control
Ragsdale/V Area
TPHIn
Groundwater
Horizontal Wells for
Migration Control
Area for
Natural
Attenuation
Assessment
Extent of Soil Contamination
(Human and Ecological Risk)
Existing Monitoring Wells
Area G Ramp
Indicates Approximate
Direction of Groundwater Flow
Travis AFB Groundwater IROD
-------
APPENDIX B
MONITORING STRATEGY
-------
TABLE OF CONTENTS
Page
APPENDIX B: MONITORING STRATEGY
B.I Monitoring of Natural Attenuation Sites B-l
B.2 Monitoring of Extraction, Treatment, and Discharge Sites B-9
LIST OF FIGURES
Page
B-l General Locations for Monitoring Wells During Screening Phase B-4
-------
APPENDIX B
MONITORING STRATEGY
Alternative 2 (Natural Attenuation/Monitoring) and Alternative 3 (Extraction,
Treatment, and Discharge) have been selected as interim remedies that will be implemented at
the North, East, and West Industrial Operable Unit (NEWIOU) sites with groundwater
contamination. This appendix discusses natural attenuation and application of this interim
remedial action, and presents the approach for incorporating natural attenuation monitoring into
the current Travis Air Force Base (AFB) groundwater monitoring program. The strategy for
monitoring effectiveness of the extraction and treatment systems is also included. All
groundwater sites in the NEWIOU will be monitored.
B.I Monitoring of Natural Attenuation Sites
Natural attenuation of dissolved fuel and chlorinated hydrocarbon compounds has been
demonstrated at many sites in the U.S. over the past decade. This alternative has been selected as
an interim remedial action for groundwater at one Installation Restoration Program (IRP) site
(LF006) in the NEWIOU. However, natural attenuation will be evaluated at seven other sites in
the NEWIOU. The Air Force Center for Environmental Excellence (AFCEE) together with the
United States Environmental Protection Agency (U.S. EPA) have drafted technical protocols on
remediation of fuel and chlorinated solvents in the subsurface (Wiedemeier, 1995; Wiedemeier,
1996). The protocol for natural attenuation of chlorinated solvents (the "protocol") was used to
develop the approach at Travis AFB since it is the most applicable to the NEWIOU groundwater
sites. This protocol will be adopted for use at Travis AFB for implementation of the natural
attenuation/monitoring alternative. For mixed plumes, i.e., sites with both chlorinated and
non-chlorinated volatile organic compounds (VOCs), such as SD034, both protocols will be
used. For such sites, the presence of petroleum contaminants of concern (COCs) can facilitate the
degradation of chlorinated solvents. The Travis AFB Petroleum-Only Contaminated Sites
Travis AFB Groundwater [ROD B-l as of 3 December 1997
-------
(POCOS) workplan will also be relevant for studying natural attenuation at sites with petroleum
contamination.
The protocol defines natural attenuation as follows: "The term "natural attenuation"
refers to naturally-occurring processes in soil and groundwater environments that act without
human intervention to reduce the mass, toxicity, mobility, volume, or concentration of
contaminants in those media."
The Groundwater Interim Record of Decision (IROD) also expands the above definition
to include the following statement: "In addition, natural attenuation/monitoring will be
protective of human health and the ecosystem."
Natural attenuation, while including all of the above factors, often has biodegradation
as a primary mechanism for reducing contaminant concentrations. While there is often chemical
composition data concerning dissolved contaminant plumes, additional groundwater samples are
often required to determine the potential for natural attenuation to remediate contamination
within an acceptable time frame.
The majority of the dissolved phase contamination at the nine sites consists of dissolved
chlorinated solvents and their associated breakdown products such as 1,2-dichloroethene
(1,2-DCE), and vinyl chloride. In general, chlorinated solvents are less biodegradable than fuel
hydrocarbons since they are essentially man-made chemicals which are often toxic to
microorganisms in the subsurface. Chlorinated aliphatic hydrocarbons can be biodegraded
through three primary pathways, which are:
• Electron acceptor reactions (reductive dechlorination);
• Electron donor reactions; and
• Cometabolism.
Travis AFB Groundwater IROD B-2 is of 3 December 1997
-------
The goals of monitoring the groundwater for natural attenuation are to determine the
affect of natural attenuation on contaminant concentrations and secondarily to identify pathways
that are available for biodegradation of dissolved contaminants. Insufficient amounts of
substrate, variable dissolved oxygen concentrations, or the abundance of other compounds like
iron can influence the extent and degree of biodegradation of the dissolved contamination. These
factors can vary between each site, so each site needs to be evaluated separately. Natural
attenuation must be monitored in order to determine whether the risks associated with the
dissolved hydrocarbon contamination are being contained or reduced to acceptable levels.
Section 2 of the protocol presents a specific protocol for implementing natural
attenuation, which will be followed at Travis AFB. This section lays out the following nine key
steps to this protocol:
1. Review available site data and develop preliminary conceptual model.
Determine if receptor pathways have already been completed. Respond as
appropriate.
2. Apply the screening process described in Section 2.2 of the protocol to assess
the potential for natural attenuation. (Figure B-l shows generalized locations of
wells for screening.)
3. If natural attenuation is selected as potentially appropriate, perform site
characterization to support natural attenuation.
4. Refine conceptual model based on site characterization data, complete
pre-modeling calculations, and document indicators of natural attenuation.
5. Simulate natural attenuation using analytical or numerical solute fate and
transport models that allow incorporation of a biodegradation term, as
necessary.
6. Identify potential receptors and exposure points and conduct an exposure
pathways analysis.
7. Critically and realistically evaluate practicability and potential efficiency of
supplemental source control. Compare the benefits of source removal to the
practicability and potential efficiency of source removal.
Travis AFB Groundwater IROD B-3 as of 3 December 1997
-------
Establishes
Background A
Geochemical
Conditions
Helps Define
Lateral Extent of
Contamination
Helps Define
I Downgradient Extent
of Contamination
WurneMigration: -:J-
J" -•-•'**"''v?^s»v?Siil-
= Required Data Collection Point
Not to Scale
(Adapted from Wiedermeirer. et a/, 1996)
Figure B-l. General Locations for Monitoring Wells During Screening Phase
Travis AFB Groundwalcr IROD
B-4
as of 3 December 1997
-------
8. Prepare long-term monitoring and verification plan for the selected
alternative - natural attenuation alone or in concert with supplemental
remediation systems.
9. Present findings to regulatory agencies and negotiate for the selected alternative.
These steps are described in more detail in the protocol. For the Travis AFB NEWIOU
groundwater sites, some of these steps have already been completed during the Remedial
Investigation/Feasibility Study (RI/FS) process.
Information will be collected during the interim period to determine if natural
attenuation will work at a site. The following situations would support the viability of natural
attenuation at a site:
• The hydrogeology and the contamination transport and fate issues of the site are
well understood;
• Contamination sources have been identified and have been, or will be,
appropriately remediated;
• The natural attenuation processes at work at the site have been characterized and
determined to be capable of achieving the required cleanup levels or objectives
in a feasible time frame;
• Historical data indicating a consistent decline in contaminant concentrations
over time, and a retreating or stable plume;
• Hydrogeologic or chemical data that can indirectly demonstrate the type(s) of
natural attenuation processes active at the site, and the rates at which those
processes are reducing contamination levels. For example, indicator compounds
such as oxygen, nitrate, sulfate iron (II), methane and contaminant daughter
products are often used to estimate the potential for contaminants to be
attenuated through biodegradation.
Use of monitored natural attenuation offers several potential advantages, such as the
potential to lower overall remediation costs, particularly at large sites. However, natural
Travis AFB Groundwater IROD B-5 as of 3 December 1997
-------
attenuation also has potential disadvantages. The main one is that cleanup time is sometimes
significantly longer than active remediation and responsibility must be assumed for long term
monitoring and associated costs. In addition, site characterization may be more complex and
costly.
Some compounds are more prone to naturally attenuate than others. For instance, many
of the regulated components of fuel hydrocarbons (e.g., benzene, toluene, ethylbenzene and
xylene [BTEX]) often biodegrade to non-toxic compounds in the subsurface under a variety of
environmental conditions. Other compounds, such as certain chlorinated volatile organics
(e.g., trichloroethylene) are less prone to biodegrade than BTEX, but may do so in certain
conditions. Other factors to consider are whether natural attenuation will result in the creation of
daughter products whose toxicity is greater than the parent, or whether contaminants will be
transferred to other media. Where conditions are favorable, natural attenuation may reduce
contaminant mass or concentration quickly enough to safely incorporate it as part of the overall
site remedy.
At Travis AFB there is a potential for all contaminated groundwater to migrate along
sewer lines and other preferential pathways. Alternative 3 (extraction) will be implemented at
some sites to control migration of contaminated groundwater along preferential pathways. At
other sites where the remedy selection is deferred until the final ROD, precautions will be taken
to ensure that preferential migration does not occur at these sites.
The Air Force will develop a Natural Attenuation Assessment Plan (NAAP) which
establishes a method to implement Alternative 2 during the five-year interim period. The
schedule for submitting a NAAP Work Plan will be included in the Groundwater NEWIOU
RD/RA Work Plan. The NAAP will describe the Air Force's approach for assessing natural
attenuation at LF006, the deferred sites, deferred portions of plumes, and will incorporate
information from the AFCEE Pilot Study at SD036. The NAAP will be based on the
EPA/AFCEE document "Technical Protocol for Evaluating Natural Attenuation of Chlorinated
Travis AFB Growidwater IROD B-6 as of 3 December 1997
-------
Solvents in Groundwater" (Wiedemeier, et al, 1996). The NAAP will include a Natural
Attenuation Decision Matrix which provides a methodology to assess the effectiveness of natural
attenuation. The Natural Attenuation Decision Matrix will include methods to:
• Determine which portions of plumes are appropriate for Alternative 2 and/or 3;
• Identify where additional characterization is needed;
• Identify wells for groundwater monitoring and analytical parameters;
• Develop methods to determine migration rate of plume;
• Determine "trigger action" to implement contingency action;
• Predict timeframe for site cleanup;
• Identify modeling needs;
• Incorporate results from SD036 Pilot Study into NAAP; and
• Update NAAP as needed.
Recommendations for Groundwater Monitoring
Monitoring will follow the guidelines in the protocol and will consist of locating
groundwater monitoring wells and developing a groundwater sampling and analysis strategy.
This plan will be used to monitor plume conditions over time and to verify that natural
attenuation is occurring at rates sufficient to stabilize the plume. The long-term monitoring plan
will be developed based on site characterization data and the results of solute fate and transport
modeling.
The long-term monitoring plan will include two types of monitoring wells. Long-term
monitoring wells are intended to determine if the plume is stable. Point-of-compliance
Travis AFB Groundwater IROD B-7 as of 3 December 1997
-------
(or point-of-action) wells are intended to detect movements of the plume outside the negotiated
perimeter of containment, and to trigger an action to manage potential expansion.
Compliance wells are used to determine if a violation (non-compliance) has occurred,
as measured by a significant exceedance of water quality objectives (MCLs) or a detection at
some concentration in a well that was previously uncontaminated. Compliance wells may be
located outside of the plume and/or at the water quality objective isopleth. The contaminant
plume is managed to prevent a significant increase in contamination at these wells.
Trigger wells (point-of-action wells) should be located upgradient of compliance wells
within the plume, and data from these wells should be used to predict the likelihood that the
plume will migrate to the compliance well within a given timeframe. Management actions should
be taken to insure that a violation does not occur.
The final number and placement of long-term monitoring and point-of-
compliance/action wells should be based on the behavior of the plume as revealed during the
initial site characterization and on regulatory considerations. The results of a solute fate and
transport model may be used to help site the long-term monitoring and point-of-compliance
wells. In order to provide a valid monitoring system, all monitoring wells will be screened in the
same hydrogeologic unit as the contaminant plume. This generally requires detailed stratigraphic
correlation. To facilitate accurate stratigraphic correlation, detailed visual descriptions of all
subsurface materials encountered during borehole drilling or cone penetrometer testing will be
prepared prior to monitoring well installation.
A ground water sampling and analysis plan will be prepared in conjunction with
point-of-compliance and long-term monitoring well placement. For long-term monitoring wells,
groundwater analyses will likely include VOC constituents of concern, dissolved oxygen, nitrate,
iron (II), sulfate, and methane. For point-of-compliance wells, groundwater analyses will be
limited to VOC constituents of concern. Except at sites with very low hydraulic conductivity and
Travis AFB Groundwater IROD B-8 as of 3 December 1997
-------
gradients, quarterly sampling of long-term monitoring wells is likely to be recommended during
the first year to confirm plume stability and to determine baseline data. Based on the results of
the first year's sampling, the sampling frequency may be reduced to annual sampling. The
sampling will be coordinated with Travis AFB Groundwater Sampling and Analysis Program
(GSAP) and annual results published as an element of the GSAP Annual Report.
B.2 Monitoring of Extraction. Treatment, and Discharge Sites
Alternative 3 (Extraction, Treatment, and Discharge) is the selected interim alternative
for groundwater at 12IRP sites. The extraction strategy includes remediation of off-base
contamination, source control, and migration control. The objectives of these interim actions are:
• Off-base Remediation - Reduce the off-base groundwater concentrations to
Interim Remediation Goals (IRGs) for each of the compounds.
• Source Control - Remove floating petroleum product and secondary sources of
VOC contamination (dense nonaqueous phase liquids [DNAPLs]).
• Migration Control - Prevent migration of contaminated groundwater during
the period of the IROD.
During the design task, all sites will be evaluated in regards to the selected remedies
that were identified for each site. The task will specify the location of each monitoring well
included and will identify the location and design of any additional monitoring wells that will be
needed. The existing groundwater monitoring wells should be evaluated for suitability, and
additional wells should be installed if needed. Historical groundwater sampling results will be
used to help minimize duplicate analyses that have already been performed. All groundwater
sites will be reviewed for natural attenuation.
The Air Force will also develop a strategy for evaluating migration into and out of
storm drains. The objective is to evaluate the effectiveness of actions taken to address
Travis AFB Groundwater IROD B-9 as of 3 December 1997
-------
groundwater/surface water interactions. Any monitoring will be coordinated with the Travis AFB
Stormwater Program.
The monitoring wells (location and screen interval) and the analyses (methods and
frequency) needed to collect the data to support the evaluation of the extraction system will be
defined in the detailed design for each site. The data will then be reported and evaluated annually
as part of the GSAP Annual Report prior to the formal five-year period to assess if the objectives
of the interim actions are being met.
Travis AFB Groundwater IROD B-10 is of 3 December 1997
------- |