PB98-964305
EPA 541-R98-168
March 1999
EPA Superfund
Record of Decision:
Iowa Army Ammunition Plant
OU1
Middletown, IA
3/4/1998
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INTERIM ACTION
RECORD OF DECISION
DECLARATION
SITE NAME AND LOCATION
Iowa Army Ammunition Plant (1AAAP)
Soils Operable Unit (OU)
Ntiddletown. Iowa
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected interim remedial action for contaminated soils ai
15 areas throughout the IAAAP in Middletown. Iowa. The interim remedial action was
chosen in accordance with the Comprehensive Environmental Response. Compensation and
Liability Act (CERCLA). as amended by the Superfund Amendments and Reauthorization Act
(SARA), and to the extent practicable, the National Contingency Plan (NCP). This decision is
based on information in the site Administrative Record file, which is located in the following
information repositories:
Iowa Army Ammunition Plant Burlington Public Library
Visitor Reception Area 501 N. Fourth Street
Building 100-101 Burlington, Iowa 52601
Middletown, Iowa 52683-5000 (319) 753-1647
(319)753-7710
Danville City Hall
105 W. Shepard
Danville, Iowa 52623
(319)392-4685
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The U.S. Army (Army* has coordinated selection ot this interim remedial action with the U.S.
Environmental Protection Agency (EPA). The Army is the lead agency for implementing the
interim remedial action at the IAAAP. As the support agency, the EPA oversees the cleanup
activities conducted by the Army to ensure that requirements of CERCLA/SARA, the NCP,
and the Federal Facilities Agreement between the Army and the EPA have been met. EPA
concurs with the selected remedy. The state of Iowa has not participated in the review of
CERCLA clean up activities at the IAAAP and has declined to comment upon the preferred
alternative presented in the Proposed Plan for this Interim Remedial Action.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision, may present an
imminent and substantial endangerment to the public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY
The IAAAP has been divided into a soils OU and a groundwater OU to facilitate management
of contaminated wastes at the site. The Remedial Investigation for the soils OU is effectively
complete and has been followed by a Focused Feasibility Study (FFS). Additional data have
been requested by the EPA to complete the investigation of the groundwater OU. The selected
interim remedial action presented here addresses one of the principal threats posed by the soils
OU by temporarily stockpiling, for future treatment, the most highly contaminated soils; and
by permanently disposing the remaining contaminated soils. This Interim Action for the soils
OU is expected to be a component of the final action for the soils OU. The Interim Action
will provide for risk reduction at the site while evaluations of innovative technologies to
potentially treat the principal threat wastes are being conducted. Pilot study tests are
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underway at the 1AAAP to evaluate bioremediation technologies at the time of this record of
decision (ROD). The most highly contaminated soils will be stockpiled in the on-siie
corrective action management unit (CAMU). which is constructed to specifications which meet
Resource Conservation and Recovery Act (RCRA) Subtitle C landfill requirements. The
CAMU will be used to temporarily store CERCLA remediation wastes as specified in the EPA
Memorandum dated March 8. 1995 entitled 'Designation of Corrective Action Management
Unit. Iowa Army Ammunition Plant Site. Middletown. Iowa' (see Appendix F of the IAAAP
FFS for the soils OU). The remaining contaminated soils will be permanently disposed in
either che on-site Soil Repository, which is also constructed to RCRA Subtitle C landfill
specifications, or the on-site Inert Landfill. A synthetic liner
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Temporary storage of contaminated soils with risk levels above 10~5. or that fail
land disposal restriction iLDR) criteria, in the designated CAMU on site, with a
treatment method tor these stockpiled soils to be specified in the final soils OU
ROD
Permanent disposal or contaminated soils with risk levels between 103 and 10"*
in the on-site Soil Repository
Permanent disposal or contaminated soils with risk levels below 10'° and above
the leaching RGs in the on-site Soil Repository or the on-site Inert Landfill
Solidification;stabilization or contaminated soils containing metals at levels
exceeding LDR criteria, and permanent disposal in the on-site Soil Repository
STATUTORY DETERMINATIONS
The selected interim action is protective of human health and the environment, complies with
Federal and State of Iowa requirements that are legally applicable or relevant and appropriate
to the remedial action, and is cost-effective. This action utilizes permanent solutions and
alternative treatment technologies to the maximum extent practicable for this site, given the
limited scope of the action. Because this action does not constitute the final remedy for the
IAAAP soils operable unit, the statutory preference for remedies that employ treatment to
reduce toxiciry, mobility, or volume as a principal element will be addressed at the time of the
final response action for the soils operable unit. A subsequent action is planned to fully
address the principal threats posed by this operable unit.
IV
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Because this remedy will result in hazardous substances remaining on site with contamination
levels exceeding pertinent health-based standards, a review will be conducted within five years
after commencement or remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment. Because this is an interim action
ROD. review of this site and of this remedy will be ongoing as final remedial alternatives for
ihe IAAAP soils OU are developed.
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INTERIM ACTION
RECORD OF DECISION
SOILS OPERABLE UNIT
IOWA ARMY AMMUNITION PLANT
MIDDLETOWN. IOWA
Prepared by:
U.S. Army Environmental Center
SFTM-AEC-IRA; Building E4480
Aberdeen Proving Ground, Maryland 21010-5401
October 1997
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TABLE OF CONTENTS
SECTION PAGE
1.0 Site Name. Location, and Description 1
2.0 Site History and Enforcement Activities 1
3.0 Highlights of Community Participation 7
4.0 Scope and Role of Operable L'nits 8
5.0 Summary of Site Characteristics 9
6.0 Summary of Site Risks 13
6.1 Human Health Risks 13
6.1.1 Contaminant Identification 13
6.1.2 Exposure Assessment 14
6.1.3 Toxicity Assessment 15
6.1.4 Risk Characterization 17
6.2 Environmental Risks 18
7.0 Description of Alternatives 19
7.1 Alternative 1 20
7.1.1 Technology Description 21
7.2 Alternative 2 23
7.2.1 Technology Description 24
7.3 .Alternative 3 25
ii
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TABLE OF CONTENTS
(continued)
SECTION PAGE
7.3.1 Technology Description 26
8.0 Summary of Comparative Analysis of Alternatives 27
8.1 Overall Protection of Human Health and the Environment 28
8.2 Compliance with Applicable or Relevant and Appropriate
Requirements 28
8.3 Long-term Effectiveness and Permanence 32
8.4 Reduction in Toxicity, Mobility, or Volume Through
Treatment 32
8.5 Short-term Effectiveness 33
8.6 Implementability 33
8.7 Cost 34
8.8 State/Support Agency Acceptance 35
8.9 Community Acceptance 35
9.0 Selected Remedy 35
9.1 Major Components 35
9.2 Remediation Goals 36
9.3 Cost 37
10.0 Statutory Determinations 38
10.1 Protection of Human Health and the Environment 39
in
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TABLE OF CONTENTS
{continued)
SECTION PAGE
10.2 Compliance with ARARs 40
10.2.1 Location-Specific ARARs 40
10.2.2 Chemical-Specific ARARs 40
10.2.3 Action-Specific ARARs 42
10.3 Cost-Effectiveness 43
10.4 Utilization of Permanent Solutions and Alternative
Treatment Technologies (or Resource Recovery Technologies)
to the Maximum Extent Practicable 44
10.5 Preference for Treatment as a Principal Element 46
11.0 Documentation of Significant Changes 46
12.0 Responsiveness Summary 47
12.1 Overview 47
12.2 Community Involvement 48
Tables
Table 1 Targeted Areas: Contamination Type and Volume 49
Table 2 Preliminary Soil Remediation Goals: Human Health 50
Table 3 Preliminary Soil Remediation Goals: Leaching 50
Table 4 Alternative 1: Cost Estimate from FFS 51
Table 5 Alternative 2: Cost Estimate from FFS 51
Table 6 Alternative 3: Cost Estimate from FFS 52
IV
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TABLE OF CONTENTS
(continued)
Table 7 Alternative 1: Revised Cost Estimate
Table 8 Alternative 2: Revised Cost Estimate
Table 9 Alternative 3: Revised Capital Cost Estimate
Table 10 Alternative 3: Annual Operations and Maintenance Costs
53
54
55
56
Figures
Figure 1
Figure 2
General Area Layout
CERCLA Solid Waste Management Units (Restoration Sites)
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ACRONYMS
ARAR
Army
BLRA
CAMU
CERCLA
COC
COPEC
CPF
DL
DMT
DOD
EPA
EPC
F
FFA
FFS
FS
GCL
Applicable or relevant and appropriate requirement
U.S. Army
Baseline risk assessment
Corrective action management unit
Comprehensive Environmental Response. Compensation and Liability
Act
Contaminants of concern
Contaminant of potential ecological concern
Cancer potency factor
Detection limit
Dinitrotoluene
Department of Defense
U.S. Environmental Protection Agency
Exposure point concentration
Fahrenheit
Federal Facilities Agreement
Focused Feasibility Study
Feasibility Study
Geosynthetic clay liner
VI
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HAL
HDPE
HI
HIF
HMX
IAAAP
kg
LAP
LDR
mg
NB
NCP
NPL
NIC
OU
PA
PAH
PCB
ppm
RCRA
RDX
RfD
RG
Rl
RME
ROD
SARA
Health advisory level
High-density polyethylene
Hazard index
Human intake factor
High melting explosive
Iowa Army Ammunition Plant
Kilogram
Load, assemble, and pack
Land disposal restriction
Milligram
Nitrobenzene
National Contingency Plan
National Priorities List
Non-time critical
Operable unit
Preliminary assessment
Polynuclear aromatic hydrocarbon
Polychlorinated biphenyl
Pans per million
Resource Conservation and Recovery Act
1,3,5-Trinitro-l .3,5-triazacyclohexane
Reference dose
Remediation goal
Remedial Investigation
Reasonable maximum exposure
Record of Decision
Superfund Amendments and Reauthorization Act
vn
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SI Site inspection
SVOC Semi-volatile organic compound
TCLP Toxictty Characteristic Leaching Procedure
TNB Trimtrobenzene
TNT Trinitrotoluene -
TSCA Toxic Substance Control Act
UCL Upper confidence limit
VOC Volatile organic compound
vdj Cubic vard
Vlll
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1.0 Site Name. Location, and Description
The Iowa Army Ammunition Plant (1AAAP) is a load, assemble, and pack (LAP) munitions
facility located in Middletown. a rural area or eastern Iowa. 10 miles west of Burlington in
Des Moines County, and approximately nine miles northwest of the Skunk and Mississippi
Rivers (see Figure 1). Croplands comprise about 60 percent of the county; the remaining area
is composed of 10 percent urban use. eight percent pasture use. and 22 percent woodland or
idle land. The IAAAP is located on about 20.000 acres. Approximately 8.000 acres are
leased tor agricultural use. about 7.500 acres are forested, and the remaining area is used for
administrative and industrial operations. Deer hunting is regulated at the IAAAP through the
use of permits. Approximately 43 housing units have been transferred to the city of
Middletown.
The northern area of the IAAAP consists of gently undulating terrain. The central portion is
characterized by rolling terrain dissected by a shallow drainage system, while the southern
area of the site contains drainage ways with steep slopes down to the creek beds. Elevations
within the IAAAP range from 730 feet above mean sea level in the north to 530 feet in the
south. There are four principal aquifers in Des Moines County. These include a shallow or
surficial aquifer (drift aquifer) in unconsolidated Recent Pleistocene sediments, and bedrock
aquifers occurring in the Mississippian, Devonian, and Cambro-Ordovician units.
The IAAAP contains four watersheds. Brush Creek drains the central ponion of the site, exits
at the southeastern boundary, and flows into the confluence of the Skunk and Mississippi
Rivers. The creek's floodplain at the southern boundary of the site is estimated to be 200 feet
wide. Spring Creek drains the eastern ponion of the site, exits at the southeastern corner, and
flows off site directly into the Mississippi River. The creek's floodplain at the southeastern
boundary of the site is estimated to be 400 feet wide. Long Creek drains the western portion
of the IAAAP, exits at the southwestern boundary, and joins the Skunk River just south of the
site. The Skunk River then flows into the Mississippi River. The Long Creek drainageway
has been dammed near the center of the site to create the 85-acre George H. Mathes Lake.
Use of this lake by the plant as a water source was discontinued in January 1977. A campsite
and a boat ramp used by fishermen are present at the lake. North of Mathes Lake is the 7-acre
1
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Stump Lake, which was built to serve as a sediment control tor Mathes Lake. The floodplain
of Long Creek is widest (500 feet) at the southern plant boundary. The Skunk River is located
south of the IAAAP. bordering the site's perimeter on the southwest corner. The Skunk
River provides year-round recreational use.
The 15 areas within the IAAAP that require interim remedial action are impacted with various
contaminants and contain an estimated volume of over 42.000 cubic yards (ydj) of
contaminated soils. Table 1 provides specific information on types of contaminants and
estimated volumes of contaminated soils for each of these 15 areas. Figure 2 shows the
locations of these 15 areas within the IAAAP.
2.0 Site History and Enforcement Activities
The IAAAP produced munitions for World War II from the plant's inception in September
1941 until August 1945. and munitions for military activities in Southeast Asia in the 1960s
and early 1970s. Activities at the IAAAP continued at a reduced level during peacetime. Day
& Zimmerman Corporation operated the plant from-1941 - 1946. The former Atomic Energy
Commission operated at Line 1 from 1948 through mid-1975. Plant operations reverted to
U.S. Army (Army) control from 1946 - 1951. The Army continues to own the IAAAP,
which has been operated by the private contractor Mason & Hanger Corporation since 1951.
The IAAAP currently is operating to LAP munitions, including projectiles, mortar rounds,
warheads, demolition charges, anti-tank mines, anti-personnel mines, and the components of
these munitions, including primers, detonators, fuses, and boosters. Only a few of the
production lines are in operation.
The primary source of contamination at the site is attributable to past operating practices in
which explosives-contaminated wastewater and sludge were discharged to uncontrolled, on-site
lagoons and impoundments. Pink/red wastewater from trinitrotoluene (TNT) operations is a
listed hazardous waste (K047) according to the Resource Conservation and Recovery Act
(RCRA).
The U.S. Environmental Protection Agency (EPA) added the IAAAP to the National Priorities
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List < NPIJ in 1990. The NPL is the EPA's list of sites that appear to pose the greatest threat
to human health and the environment, based on the site assessment process. The Department
ot Defense (DOD) established the Defense Environmental Restoration Account to address sites
under the Comprehensive Environmental Response. Compensation and Liability Act
(CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA), that
are within the responsibility of the DOD. The Defense Environmental Restoration Account
has been renamed Environmental Restoration. Army (ER.A). The Army, as an agency within
the DOD. is the lead agency for implementing the interim remedial action at the IAAAP. As
the support agency, the EPA oversees cleanup activities conducted by the Army to ensure that
the requirements of CERCLA/SARA and the National Contingency Plan (NCP) have been
met. The EPA and the Army signed a Federal Facilities Agreement (FFA) for site cleanup,
which became effective December 10. 1990. following public comment. The FFA. provides a
framework for CERCLA response actions to be performed at the IAAAP. including the
investigation and cleanup of contamination. The State of Iowa has declined to panicipate as a
signatory parry to this FFA.
The Army has conducted numerous investigations at the site from 1975 to the present. The
following briefly summarizes the investigations conducted since the FFA was signed.
The Army conducted Preliminary Assessments (PA) and Site Inspections (SI) at the IAAAP to
identify areas of potential contamination. The Army, based on previous investigations or
knowledge of operational and waste handling practices, identified 43 areas of known or
suspected contamination during the PA. In August 1991. an SI was conducted for each of the
43 areas. Limited soil, sediment, groundwater, and surface water sampling was conducted in
an effort to determine whether chemical constituents were present at levels of concern at
suspected source areas and in associated migration pathways. Data obtained during the PA/SIs
were used to supplement data previously obtained by the Army to develop the list of areas to
be investigated within the Remedial Investigation (RI). The presence of chemical constituents
above analytical reporting limits indicated a need for further evaluation.
The Army conducted the Phase I RI from July through November 1992. The Phase I
investigation included an expanded characterization of background levels of metals in soils, a
soil gas sampling effort in order to discern the extent of contamination by volatile organic
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compounds (VOO. base-wide surface water and sediment sampling, base-wide groundwater
sampling, installation of temporary groundwater monitoring wells (piezometers), off-post
residential well sampling, field screening for metals and explosives in soils, and fixed
laboratory analyses of approximately 20 percent of the field screening samples collected and
analyzed. The results of the off-post residential well sampling effort indicated the presence of
explosives in excess of EPA health advisory levels (HAL) in five of the wells sampled.
Contaminated wells were located southwest of the site near the town of Augusta, and off-site
in the Brush Creek watershed. As an interim action, the Army provided affected residences
with bottled water. The Army then contracted with the local public water supply company to
have potentially impacted residences located south of the IAAAP boundary connected to the
rural water supply district.
Results of the Phase I RI were used to refine the soil and groundwater investigation in the
Phase II RJ. which commenced in April 1993. During the Phase II RI. 13 soil borings were
advanced to depths Of approximately 15 feet below ground surface to obtain additional
information regarding subsurface conditions at five areas. A total of 80 groundwater
monitoring wells were placed at the site during the RI. During placement of each well, soil
samples were obtained at the soil/groundwater interface and submitted for fixed laboratory
analysis. Following placement of monitoring wells, each well was sampled for chemical
constituents indicated by previous data obtained and knowledge of past operational and waste
handling practices specific to that site.
The Draft RI Report, which included data obtained during the Phase I and Phase II RI. was
submitted by the Army in 1993 to the EPA for review and comment. It was subsequently
determined that collection of additional data was necessary to complete the site
characterization. The Follow-On Sampling field effort was conducted in April through August
1995 to obtain additional data to characterize the nature and extent of on-site contamination.
The Follow-On Sampling consisted of the placement of 28 additional soil borings and 26
groundwater monitoring wells, soil sample collection adjacent to previously unsampled
explosives wastewater sumps, shallow soil sampling to verify positive results from the soil gas
sampling during the Phase I RI. and collection of stream gauging data and shallow
groundwater levels in an effort to characterize the hydraulic connection between surface water
and shallow groundwater. Following the additional field sampling effort, the Draft-Final RI
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Report was submitted in November 1995. The Army received and incorporated comments
from the EPA on this document, and the Revised Draft-Final RJ Report dated May 21. 1996
was accepted as final in accordance with the FFA.
A Focused Feasibility Study
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In the tall of 1996. the Army began activities to construct a low permeability cover on the 17-
acre Inert Landfill sue. The cover will consist of a geonet drainage layer and a low
permeability geomembrane with appropriate vegetative cover. The liners will prevent
infiltration of precipitation into the landfill material and the subsequent transport of
contaminants from wastes to groundwater. Industrial and municipal-type wastes had been
disposed in the Inert Landfill by the Army prior to the advent of current-day waste
management regulations. The migration of contaminants leaching from these wastes to
groundwater represents a continuous source of contaminants that will be mitigated by the
construction of the cover.
The Line 1 Impoundment and Line 800 Pink Water Lagoon sub-sites are considered to be the
greatest sources of explosive contamination at the IAAAP. As a part of the NTC removal
actions for the Line 1 Impoundment and the Line 800 Pink Water Lagoon, which are on-going
at the time of this ROD. soils have been sampled, analyzed, and segregated according to the
risk or contaminant level detected. Depending on the concentration of explosives in the
excavated soils, the soils have been placed in one of three areas: in the Soil Repository
constructed adjacent to the IAAAP Inert Landfill: in the designated Corrective Action
Management Unit (CAMU) also constructed adjacent to the Inert Landfill; or beneath the cap
at the Inert Landfill as random fill to achieve final grade. Contaminated soils at the Line 1
Impoundment and Line 800 Pink Water Lagoon were excavated and segregated in August
1997. Site restoration activities are scheduled to be complete by early 1998.
In addition to the areas discussed above for which NTC removal actions have been undertaken,
the Army has identified 15 additional areas with soils containing chemical constituents at
concentrations greater than cleanup goals for the site. The evaluation of potential remedial
alternatives and the identification of a preferred alternative to address these areas was the
subject of the Proposed Plan for Interim Action for the IAAAP soils OU. A listing of the
areas proposed for cleanup within the scope of the soils OU interim remedial action and their
respective contaminant types is presented in Table 1. Other areas within the soils OU may
ultimately require remedial actions to address soil contaminants. However, the nature of any
such activities is not currently well defined due to the absence of definitive data or a thorough
evaluation of risks that may be posed by contaminants that are present. The cleanup of any
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additional areas that may he round to pose unacceptable risk and that are not addressed in the
soils OU Interim Action will be specified as pan or the final soils OU ROD.
3.0 Highlights of Community Participation
The RI/FS and Proposed Plan tor the soils OU were released to the public in November 1996
and May 1997. respectively. These documents were made available to the public in both the
administrative record and the site information repositories. The notice ot availability for the
Proposed Plan was published in the Burlington-Hawkeye on May 21. 1997. A public
*
comment period was held from May 22. 1997 to June 21. 1997. In addition, a public meeting
was held on June 5. 1997 at the Danville Community Center. At this meeting representatives
from the Army and EPA were available to the public to discuss concerns, accept comments,
and answer questions regarding the preferred alternative presented in the Proposed Plan.
There were no written or verbal comments regarding the Proposed Plan submitted to the Army
at this meeting or during the comment period. The remedy selected for the IAAAP is based
on the information contained in the Administrative Record for the site, and on public
comments.
The Administrative Record is available for review during normal business hours at the Iowa
Army Ammunition Plant. Visitor Reception Area. Building 100-101; the Burlington Public
Library; and the Danville City Hall.
4.0 Scope and Role of Operable Units
Due to the complexity of the problems associated with the IAAAP, the site has been divided
into two OUs to facilitate project management. These are the:
Soils OU, to address contamination in the soils, and the
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Groundwater OU. to address contamination of the groundwater aquifers.
contaminated surface water and sediments. VOC-contaminated media, and
ecological risks.
This Interim Action for the soils OU addresses the contaminated soils in 15 areas at the
IAAAP (see Table 1). These areas of the site pose the principal threat to human health and the
environment due to risks from possible ingestion or dermal contact with soils, and due to
potential contaminant leaching from soil to groundwater. This Interim Action will address the
principal threat and reduce risks at the site while a final remedial action for the IAAAP soils
OU is being developed. The Interim Action will contain, in on-site landfill facilities, soils
contaminated at levels posing a potential health threat, or acting as a potential source of
continuing groundwater contamination.
Since this is an interim action, several elements of the final remedy have been deferred to the
final ROD for the soils OU. Other contaminated areas within the soils OU may ultimately
require remedial actions, however, conclusive sampling data in these areas has not been
evaluated to date and therefore the nature of any potential remedial activities is not currently
well defined. The cleanup of any additional areas that may be found to pose unacceptable risk
that are not addressed in this Interim Action will be included as part of the final soils OU
ROD. Other elements which will be addressed in the final soils OU ROD would include long-
term actions, such as institutional controls to restrict access and land usage at the Inert Landfill
Area and to restrict remediated areas to commercial / industrial land usage in the future,
consistent with the cleanup goals. In addition, the final remedy for the soils OU will include a
long-term monitoring plan for the IAAAP Inert Landfill Area to monitor the performance and
integrity of the Soil Repository and the Inert Landfill, and will specify means by which the
CAMU will be ultimately closed.
Contaminated groundwater is a principal threat at this site due to the potential for direct
ingestion of drinking water from wells that contain contaminants above health-based levels.
Additional data have been requested by the EPA to complete the investigation of the
groundwater OU. It is anticipated that these data gaps will be filled during the 1997 sampling
season to complete the groundwater investigation. An FS. Proposed Plan, and ROD for the
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groundwater OU will be prepared and submitted for public review and comment. A Final
ROD will be issued for the sue that encompasses all contaminated areas or concern, including
those not addressed as a part of this soils OU interim remedial action.
5.0 Summary of Site Characteristics
The Rl performed by the Army from 1992 through 1995 focused primarily on identifying
sources of contamination resulting from previous facility operations and waste handling
practices associated with the production of ammunition, and on generally determining the
extent of the contamination in surface and subsurface soils, surface water, sediments, and
iiroundwater. Results of the soil investigation indicate that with the exceptions of the Line 1
Impoundment. Line 800 Pink Water Lagoon. Fire Training Pit. and Pesticide Pit areas.
contamination at the site generally consists of explosives and lead found in soils adjacent to
source areas at depths of up to approximately three feet below ground.
Groundwater has been found to exceed cleanup criteria at Lines 1. 2, 3. 3A. and 6; the Line
800 Pink Water Lagoon: the Explosives Demolition Area/East Burn Pads, Firing Site, and
Inert Landfill; and the Fire Training Area. Surface water and sediment quality have been
impacted by previous discharges of explosives-contaminated wastewater from washing down
the ammunition load lines. It is suspected that the surface water and shallow groundwater
within the various IAAAP watershed areas are hydraulically interconnected. The relationship
between the surface water, shallow groundwater, and chemical constituents in base-wide
sediments is being investigated as a pan of a Supplemental Hydrogeologic Study during the
1997 sampling season.
As discussed previously, 15 areas have been identified with soils containing chemical
constituents at concentrations that exceed the cleanup goals for the site. Within these 15 areas,
there are numerous sub-areas that are represented by as few as one surface or subsurface soil
sample result that exceeds the cleanup goals for the site. The extent of contamination has not
been typically defined in these isolated areas of contamination. Therefore, the Army has
calculated estimated volumes of contaminated soil that may need to be removed based on the
physical setting (e.g., boundaries formed by buildings and other adjacent structures) and
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knowledge of the site gamed during previous removal actions, such as the Explosives-
Contaminated Sumps removal action conducted in 1995. The extent of soil contamination will
he further defined during the design phase tor the interim remedial actions.
Table 1 provides a listing of the contaminant types and the estimated volumes of soils to be
removed from the interim remedial action sites. A detailed description of the nature and
extent of contamination at these sites is included in the Revised Draft-Final Rl Report and in
appendices B and E of the Soils OU FFS for the IAAAP. A brief summary of the locations.
types, and levels of contamination is presented below:
Line I. At Line 1. there are 25 separate areas from which contaminated soils will be
removed. Soils to be removed are adjacent to explosives production buildings, a vacuum
pump house, and a cooling tower. Contaminants include explosives, metals, and semi-volatile
organic compounds (SVOC). The radionuclides actinium 228 and bismuth 214 were detected
in soils along the north side of Building 1-155-1 (a cooling tower) at concentrations that
exceed site cleanup criteria. Bismuth 214 was detected in soils at the southeast corner of
Building 1-70-1 (a filter building;. The bulk of the contaminated soil volume at Line 1 is due
to explosives and lead. Total levels of royal demolition explosive (RDX) and TNT are near
1000 pans per million (ppm). and range as high as 9000 ppm. Lead levels generally range
from 2000 ppm to 5000 ppm.
Line 2. At Line 2, there are 18 areas adjacent to explosives production buildings, assembly
areas, and shipping areas that require remediation. Contaminants include explosives, at levels
totaling 500 - 1000 ppm. with percentage levels in and around sump locations, and lead
ranging from 1500 - 2000 ppm.
Line 3. At Line 3, there are 22 areas of contamination. These areas are located near a solvent
storage building, the explosives production buildings, pump houses, and a filter house.
Contaminants include explosives, metals, and SVOCs. Bismuth 214 was detected in one
sample collected south of the x-ray bay at Building 3-10. Explosives and lead are the
predominant contaminants. Explosives levels total 500 - 1000 ppm in some areas, ranging as
high as percentage levels in and around sump locations. Lead contamination is as high as
6000 ppm.
10
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Line 3 A. At Line 3A. there are eight areas of contamination located adjacent to explosives
production buildings and a pump house. Contaminants delected at concentrations that exceed
cleanup criteria include explosives and lead. Explosives generally are found at 200 - 500 ppm
in contaminated areas or Line 3A.
Lines 4A/4B. At Line 4A. one sample obtained from a drainageway south of Building 4A-07,
down gradient from a sump, contained lead at a concentration of 1160 ppm, which exceeds
cleanup criteria. None of the samples analyzed for metals at Line 4B contained concentrations
exceeding cleanup criteria for the site.
Lines 5A/5B. At Lines 5A and 5B. 10 areas of concern were identified. These areas are
located adjacent to the tetryl screening and blending facility, the tetryl pelleting operations, the
explosives assembly area, and pump house areas. Contaminants that exceed cleanup criteria
include explosives at percentage levels in sump locations, lead at 1100 ppm. and arsenic.
Line 6. None of the soil samples collected adjacent to the Building 6-19 sump contained
explosives at levels exceeding cleanup criteria for the site. Lead ranging from 3000 - 8000
ppm. and antimony were detected at concentrations exceeding cleanup criteria in samples
obtained from soils adjacent to the Building 6-96 sump.
Line 8. At Line 8. lead was detected at concentrations ranging from 1000 - 2000 ppm
adjacent to Foundation X and at the southwest corner of Building 8-81-4 (an ammonium nitrate
kettle house).
Line 9. At Line 9. beryllium was detected from the excavation area of a former sump at
levels exceeding RGs. Lead at 1270 ppm was detected adjacent to Building 9-58, a mixing
building.
Line 800. There are four areas of contamination at Line 800 that exceed cleanup criteria.
These areas include the settling ponds associated with the Line 800 Pink Water Lagoon
(explosives), the northwest corner of Building 800-04 (explosives), an area adjacent to the east
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end or Building 800-04 dead), and an area along the west side of Building 800-191 (lead).
Explosives are found in the range of 1500 - 2000 ppm. Lead was detected at 1800 ppm.
Explosives Demolition Area/East Burn Pads. At the Explosives Demolition Area and East
Burn Pads, explosives were detected in sediment samples collected from drainageways on the
east and west sides of the burn pads. Explosives also were detected in soils at 16 locations
associated with the burn pads. Explosives levels range from 1500 - 2000 ppm, to percentage
levels in some pad locations. Based on practices at the site and the contaminant levels found,
the possibility exists that solid phase explosives are present at the Burn Pads.
Demolition Area/Deactivation Furnace. Lead was detected at 6400 ppm at a location along the
southeast corner of the deactivaiion furnace.
Burn Cages/West Burn Pads Area. Low levels of explosives (less than 10 ppm) and lead at
2000 - 5000 ppm were detected at concentrations that exceed cleanup criteria in the Ash
Disposal Landfill, the west burn pads, and west burn pads landfill, and along the southeast
corner of Building BG-13 near a truck loading dock.
North Burn Pads. Lead, arsenic, and antimony were detected at concentrations that exceed
cleanup criteria for the site adjacent to Pad 1-N. Lead was detected at 12000 ppm.
Roundhouse Transformer Storage Area. Polychlorinated biphenyl (PCB) 1260 was detected at
20 ppm. exceeding cleanup criteria for the site at two locations in the northeast corner of the
former pad location.
6.0 Summary of Site Risks
A baseline risk assessment (BLRA) to assess the potential effects of contamination resulting
from past operations at the IAAAP on human health and the environment was prepared by the
Army, and is included in the Revised Draft-Final RI Report. The BLRA was conducted in
accordance with appropriate EPA guidance.
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Actual or threatened releases or hazardous substances from this sue. if not addressed by
implementing the response action selected in this ROD. may present an imminent and
substantial endangerment to public health, welfare, or the environment.
6.1 Human Health Risks
Within the BLRA for the 1AAAP. the reasonable maximum exposure (RME) to chemical
constituents at the site was evaluated. The following is a summary of the four steps used to
assess the site-related human health risks.
6.1.1 Contaminant Identification
Contaminants or concern (COO that are in surface and subsurface soils, groundwater. surface
water, and sediments were selected as part of the BLRA. using data previously collected at the
site. Initially, any chemical constituent detected in a medium was considered a potential COC.
Eighty-eight potential COC were identified. Chemical constituents were eliminated from
consideration in the BLRA if they were detected infrequently or if they are essential nutrients
and are nontoxic at the levels encountered at the 1AAAP. Seventy-seven COC were ultimately
selected. Appendix 1 in Volume 11 (Risk Assessment) of the 1996 Revised Draft-Final RI
Report for the IAAAP presents the COC in each medium of concern, and the concentrations of
the COC on which the risk assessment was based.
6.1.2 Exposure Assessment
Based on a review of site conditions, including current and anticipated future land use,
contaminant distribution, and human activity patterns, the populations most likely to be
exposed to chemical constituents at the IAAAP are on-site workers, off-post residents (both
adults and children), and on-site visitors. The following exposure pathways were judged to be
the most important:
Ingestion of contaminated groundwater, soils, surface water, and sediments,
Dermal contact with groundwater. soils, surface water, and sediments, and
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Inhalation exposure to VOCs released from groundwater to indoor air.
As an addendum to the BLRA. exposure scenarios were evaluated to address future land use
conditions at the site. Reasonably anticipated future land use at the IAAAP is expected to be
of the commercial/industrial type. Risks associated with future land use are similar in nature
but greater in magnitude than risks associated with current use. The leaching of contaminants
to shallow groundwater and human consumption of the contaminated groundwater by workers
in a commercial/industrial future land use scenario represents the greatest potential human
health risk associated with the site.
Exposure points were selected based on assumed activity patterns of potentially exposed
populations at each area of the IAAAP. Calculations of exposure point concentration (EPC)
were based on the 95 percent upper confidence limit (UCL) of the arithmetic mean
concentrations of chemicals in each medium, assuming that each data set is log-normally
distributed. It was further assumed that EPCs would remain constant over the next 30 years.
Data associated with duplicate samples were averaged. Further adjustments to data sets were
made for non-detects. Detection limits (DL). analogous to EPA sample quantitation limits,
were used to evaluate non-detects. If a chemical was detected at least once in a medium at an
exposure point, the chemical was assumed to be present in that medium, and the UCL of the
arithmetic mean was calculated using one-half the DL for nondetects. If the calculated
arithmetic mean exceeded the maximum detected value, the maximum detected value was used
as the EPC. If a chemical was never detected in a medium, it was assumed to be absent, and
the EPC was assumed to be zero.
The following briefly describes the derivations of the EPCs for the various media. EPCs for
contaminated soils were derived from analytical data for surface soil samples only, to a depth
of 0.5 foot. It was assumed that exposure at each area is equally likely at any part of the site,
and that the entire site is as contaminated as the areas sampled. Exposure points selected for
surface water exposure were Mathes Lake and the Pink Water Lagoon. All surface water
samples associated with Mathes Lake were included in the calculation of EPCs for Mathes
Lake surface water. EPCs for the Pink Water Lagoon surface water were derived from the
maximum plausible exposure scenario presented in the endangerment assessment prepared by
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c
the Army in 1989. Sediment samples collected from near shore in Mathes Lake were used to
:alculate sediment EPCs tor Mathes Lake sediment. Each groundwater EPC is based on
analytical data from a single off-site groundwater well currently used as a source of domestic
water. The EPC for indoor air was derived from an assumed air to water concentration ratio
of 0.5 for VOCs in off-site domestic wells (the only VOC detected in off-site wells is
chloroform i.
Derivation of human intake factor
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from exposure to chemicals exhibiting noncarcmoeenic effects. RfDs. which are expressed in
units of mg/kg-day. are estimates of lifetime daily exposure levels tor humans, including
sensitive individuals. Estimated intakes or chemicals from environmental media (e.g., the
amount of a chemical ingested from contaminated drinking water* can be compared to the
RfD. Reference doses are derived from human epidemiological studies or animal studies to
which uncertainty factors have been applied (e.g.. to account for the use of animal data to
predict effects on humans). These uncertainty factors help ensure that the RfDs will not
underestimate the potential for adverse noncarcinogenic effects to occur.
RfD values for the BLRA for the IAAAP were derived from published oral and inhalation RfD
values. RfDs for some PAHs were extrapolated from values available for structurally similar
PAHs. The RfDs for COCs at the IAAAP that have noncarcinogenic effects are presented in
Tables 4-1 and 4-2 of the 1996 Revised Draft-Final RI Report for this site.
Dermal exposure toxicity values were calculated based on absorbed doses, rather than
exposure doses. Dermal toxicity values were approximated by extrapolating from oral toxicity
values (i.e.. multiplying oral RfD values by an oral absorption fraction, or dividing oral slope
factors by an oral absorption traction). Absorption fractions are chemical-specific, and were
derived from published toxicological studies, with the assumption that equally absorbed doses
are equitoxic. The absorption fraction for organic COCs and arsenic was assumed to be 1.0.
Absorption fractions associated with metals are chemical-specific, and range from 0.001 to 0.6
for COCs at the IAAAP.
There are six chemicals for which no toxiciry values exist. Lead was evaluated using EPA's
"PRG Screen" model for non-resident adults. The other five chemicals (aluminum, cobalt,
dibenzofuran, iron, and sulfate) were not evaluated.
6.1.4 Risk Characterization
Excess lifetime cancer risks are determined by multiplying the intake level with the cancer
potency factor. These risks are probabilities that are generally expressed in scientific notation
(such as 1x10"*). An excess lifetime cancer risk of IxlO'6 indicates that, as an upper bound, an
individual has a one in a million chance of developing cancer as a result of site-related
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exposure to a carcinogen over a 70-year lifetime under the specific exposure conditions at a
site. Estimated cancer risks from exposure to the chemical constituents present at the site for
current off-post residents using groundwater from supply wells for household purposes range
from IxlO'5 to 5x10'. Explosives have been detected in off-post supply wells at levels
exceeding EPA HALs. Cancer risks for workers at various IAAAP areas range from TxlO"8 to
3x10"*. and for IAAAP visitors risks range from 10" to 4x10 ;. These risks are attributable to
incidental ingestion of contaminated soils.
Evaluation of noncarcinogenic risk is accomplished by comparing a calculated intake with an
acceptable intake for each chemical constituent and for each pathway that contributes to a
population's exposure. The ratio of the calculated intake to the acceptable intake is the hazard
index (HI). An HI value exceeding one indicates a potential for harmful noncarcinogenic
effects. No HI values were greater than one for any current off-post residential or on-site
visitor population evaluated at the IAAAP. indicating that exposures of these populations to
chemical constituents do not appear to be significant. For workers, the HI values range as
high as 30. These non-carcinogenic risks are also attributable to incidental ingestion of
contaminated soils. Chemicals that contribute to these His in excess of one include 2,4,6-
TNT and RDX. On this basis, exposed site workers may be at risk from the noncarcinogenic
effects of these chemical constituents.
Assumptions and factors used in the BLRA for the IAAAP may have resulted in uncertainties
that may lead to either an overestimate or an underestimate of risk. Uncertainties in the BLRA
are associated with the following primary factors: selection of COCs, data quality, calculation
of EPCs, nonquantification of some exposure pathways, determination of exposure levels,
uncertainties in modeling, determination of transport pathways, evaluation of bioavailability,
and toxicity values.
6.2 Environmental Risks
An ecological risk assessment also was conducted for the IAAAP (see Volume 11 of the 19%
Revised Draft-Final RI Report). In this ecological risk assessment, a qualitative evaluation of
contaminant release, migration, and fate was conducted using the contaminant of potential
ecological concern (COPEC) that were identified for the site. Possible exposure pathways and
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receptors were evaluated, as well as known ecological effects of the COPECs. A qualitative
determination of the ecological populations most at risk was developed and endpoints were
recommended for further study. Endangered or threatened species and associated habitats
known or suspected to be present at the sue also were evaluated.
Potentially exposed populations at the 1AAAP include plants growing in contaminated soils;
soil invertebrates; wildlife (amphibians, reptiles, mammals and birds); aquatic invertebrates
and plants: and fish. Historical biological studies and the IAAAP management plans indicate a
wide array of stresses are important at this sue. These include:
Facility management practices
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7.0 Description of Alternatives
The following is a summary of the remedial alternatives proposed in the FFS for remediation
of soils OU at the 1AAAP.
7.1 Alternative 1
This alternative involves excavaiion. on-site thermal treatment, solidification/stabilization, on-
site disposal of ash from the incineration process, and on-site disposal of soils treated by
solidification/stabilization. Rotary kiln incineration has been successfully demonstrated for
treatment of explosives-contaminated soils. Based on the volume of soils to be treated, it is
anticipated that a transportable on-site incinerator would be more cost effective than a fixed
unit that would remain at the IAAAP. The implementation of incineration remedies has
proven problematic at many Superfund sites. Process prove-in, including a trial burn, is
typically required prior to beginning the incineration of contaminated soils. Additionally,
incineration typically is not well accepted by the public, requiring close coordination and
explanation to gain a level of trust and credibility. It is estimated that Alternative 1 would
require 18 - 24 months to implement at IAAAP.
The primary components of this alternative are:
1. Excavation of all targeted areas, which include approximately 42,742 yd3 of soils
containing an estimated 168,471 kg of contaminants.
2. Verification sampling to ensure that all soils contaminated above remediation goals
(RG) are excavated. RGs are identified in Section 9.2.
3. Backfilling and restoration of excavated areas with clean soils, from a borrow source
on site.
4. Segregation of excavated soils into three groups, depending on the type of contaminants
present (see Table 1):
A. Metals and Radionuclides (4,992 yd3),
B. Explosives, SVOCs. Explosives/SVOCs, and PCBs (33,737 yd3), and
C. Metals/Explosives (4,013 yd3).
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:?. Solidification/stabilization of Group A soils. This process would immobilize both
metals and radionuclides within the soil matrix.
6. Incineration of Group B soils. This process would effectively treat all the compounds
in this group to a destruction removal efficiency of over 99.99 percent.
7 Incineration of Group C soils to treat the explosives, followed by
solidification/stabilization to immobilize the metals.
8. Permanent disposal in the Soil Repository of all treated soils and ash.
7.1.1 Technology Description
The two main technologies used with this alternative are incineration and
solidification/stabilization. Incineration is a thermal treatment method in which organic
compounds are oxidized at elevated temperatures (combusted) for the purpose of their
decomposition into basic products of combustion such as carbon dioxide, water vapor, and (in
some cases) inorganic gases. In most incinerator applications, an auxiliary heat source such as
fossil fuel-fired burners is used to achieve the temperature necessary to evaporate water from
the feed material and combust the organic compounds.
Rotary kiln incineration is the most common method used in incineration of contaminated
soils. The kiln consists of a horizontal rotating cylinder lined with firebrick insulation. The
kiln is tilted slightly from the horizontal to induce a "downhill" tumbling motion of the feed
material. Seals at the feed and discharge ends of the kiln allow the introduction of feed
material and combustion air, mounting of auxiliary burners, and discharge of ash and off-gases
through fixed equipment. Combustion air for both the auxiliary burners and organic
compound combustion is provided through dedicated forced draft blower systems.
Off-gases pass through an air pollution control system that may consist of a secondary
combustion chamber (afterburner) where organic compounds remaining in the kiln off-gases
are burned, a cyclone and/or baghouse for paniculate removal, and a wet scrubber for further
paniculate removal, chemical scrubbing of inorganic compounds, and cooling of the off-gases
prior to their discharge into the atmosphere. The entire system is maintained under a slight
negative pressure gradient by means of an inducted draft blower.
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The three critical parameters for successful incineration are residence time of the feed material
at an elevated temperature, chamber temperature, and air turbulence within the chamber. The
organic compounds must he exposed to the elevated temperature of the incineration chamber
tor sufficient time to allow their complete thermal decomposition. The chamber must be
maintained at a minimum temperature consistent with the concentration and composition of
organic compounds in the feed material in order to allow the thermal decomposition to be
driven to completion. Typically, incinerator chamber temperature setpomts are in the 1400°
Fahrenheit (Pi - 1800° F range, with secondary chamber setpomts of 1850° F - 2300° F.
Because incineration is an oxidation process, sufficient combustion air and turbulence must be
provided to ensure that all organic compounds present are exposed to an oxidizing atmosphere.
This usually requires the addition of excess air over and above the "stoichiometric'1 air
required to combust the compounds at 100 percent efficiency. A trial burn usually is
performed in order to determine operational parameters that will ensure that the incinerator
effluent are within acceptable limits.
Solidification/stabilization is a technology designed to immobilize organic and inorganic
contaminants, thereby reducing the mobility and leaching potential of these constituents in
contaminated soils, sludges, and ash. It can be said that, in general, solidification refers to the
physical consolidation of contaminated materials into a hard, rock-like material. Stabilization
refers to the chemical immobilization of hazardous contaminants. The Toxicity Characteristic
Leaching Procedure (TCLP) test is often used to analyze the resulting mixture and to evaluate
if the immobilization process accomplished the desired results.
Solidification/stabilization is generally performed by mixing contaminated materials with one
or more reagents to accomplish the desired immobilization. Examples of these reagents
include Portland cement, kiln dust, fly ash, and specific and proprietary reagents on occasion.
The appropriate reagents and proportions, as well as appropriate mixture contents, are
generally determined by performing treatability studies.
Solidification/stabilization can be accomplished in-situ or ex-situ. The main advantage of ex-
situ solidification/stabilization is that the mixing process and, therefore, the final
characteristics of the structure, is much better controlled than if the mixing takes place in-situ.
Alternative 1 will utilize ex-situ solidification/stabilization.
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7.2 Alternative 1
This alternative is similar to Alternative 1. except that btoremediation is used tor treating
explosives and SVOCs instead of incineration. Bioremediation is not considered to be an
effective technology to treat PCBs. A pilot study would be required to implement
bioremediation at the IAAAP. An estimated 18-24 months would be required to implement
this alternative. Specific processes are the following:
1 - Excavation of all targeted areas, which include approximately 42.742 yd3 of soils
containing 168.471 kg of contaminants.
2. Verification sampling to ensure that all soils contaminated above RGs are excavated.
3. Backfilling and restoration of excavated areas with clean soils, from a borrow source
on site.
4. Segregation of soils into tour groups, depending on the type of contaminants present
(see Table 1):
A. Metals and Radionuclides (4.992 yd3),
B. Explosives. SVOCs. and Explosives/SVOCs (33.138 yd3),
C. Metals/Explosives (4,013 yd3), and
D. PCBs (599 yd3).
5. Solidification/stabilization of Group A soils. This process would immobilize both
metals and radionuclides within the soil matrix.
6. Bioremediation. specifically composting, of Group B soils. This process would
effectively treat all the organic compounds in this group.
7. Composting followed by solidification/stabilization of Group C soils.
8. Permanent disposal in the Soil Repository of treated soils from Groups A, B, and C.
9. Permanent disposal in the Soil Repository of Group D soils, without treatment. This
presumes the soils are contaminated with PCBs at levels less than 50 ppm, which
appears likely based on available data. Should bulk soil contaminant levels exceeding
50 ppm PCBs be detected, disposal requirements of 40 CFR 761.60 will be further
evaluated.
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7.2.1 Technology Description
The major technologies used in this alternative are composting and solidification;stabilization.
The latter technology was described during discussion of Alternative 1. Composting is a
technology that produces a final product in which explosives are bound to the soil matrix.
The Army Environmental Center has conducted several pilot-scale composting studies to
evaluate this technology for explosives-contaminated soils and sediments. Three methods of
composting (static pile, mechanical agitated vessel, and windrow) have been studied, with the
windrow method proving to be the most effective and cost efficient. The studies conducted for
windrow composting found the optimum rate of soil loading to be 30 percent using locally
available amendments. Windrows were turned daily using a commercially available windrow
turning machine. The duration of biological activity required to reduce the mobility and
toxicity of the mixture to acceptable levels was approximately 30 days.
The U.S. Army at the Umatilla Army Deport Activity in Hermiston. Oregon implemented a
full-scale remedial action, where composting was successfully utilized to treat over 14.000
tons ot explosives-contaminated soils. Based on results from the Umatilla Army Deport
Activity remedial action, it is unlikely that composting will be able to achieve RDX
concentrations below the leaching remediation goal of one ppm established for the IAAAP.
Therefore, management of composting treatment residuals is likely to be needed. A pilot
study would be required at IAAAP in order to define critical parameters required to implement
full-scale composting operations.
Facilities to be used at the IAAAP could include an asphalt pad and a temporary structure to
protect the windrows from precipitation and temperature fluctuations. Conventional equipment
(front end loader, dump trucks) and the commercially available windrow turning machine
would be used in the composting process.
7.3 Alternative 3
This alternative involves excavation of all contaminated soils, segregation of soils based on
risk levels and contaminant type, management of those soils in the existing IAAAP landfills,
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including the CAMU. the Soil Repository, and the Inert Landfill, and
solidification/stabilization of soils thai tail land disposal restriction < LDR) criteria. An
estimated 6-9 months would he required to implement this alternative, subject to access
constraints associated with IAAAP production schedules. Additional response actions would
he required beyond those specified in Alternative 3 to provide treatment of the soils stored in
the CAMU. This soil treatment would require additional time for implementation, perhaps to
include pilot studies, and would entail additional costs of $1,000,000 to $1,500,000. Specific
processes are as follows.
1. Excavation of all targeted areas, which include approximately 42.742 yd3 of soils
containing 168,471 kg or contaminants.
1. Verification sampling to ensure that all soils contaminated above RGs are excavated.
5. Backfilling and restoration or excavated areas with clean soils, from a borrow source
on site.
4. Segregation of soils into the following groups, based on the risk level and the type of
contaminants present:
A. Highly contaminated soils with risk levels greater than 10'5. and that pass LDR
criteria.
B. Moderately contaminated soils with risk levels between 10'5 and 10'", and that
pass LDR criteria.
C. Lightly contaminated soils with risk levels below 10"*. with contaminant
concentrations above Summers' model RGs (described in Section 9.0 of this
ROD), and that pass LDR criteria.
D. Soils that fail LDR or Toxic Substance Control Act (TSCA) criteria for
constituents other than metals.
E. Soils that fail LDR criteria for metals.
F. Soils that pass LDR criteria for lead, but have lead concentrations exceeding
l.OOOppm.
5. Temporary storage in the CAMU of Groups A and D soils to await appropriate
treatment or disposition.
6. Permanent disposal in the Soil Repository of Group B soils without treatment.
7. Permanent disposal in the Soil Repository or the Inert Landfill of Groups C and F
soils, as needed to achieve final grade for each of these landfills.
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8. Solidification/stabilizanon of Group E soils, and permanent disposal of the treated soils
in the Soil Repository.
7.3.1 Technology Description
The CAMU has been constructed to meet RCRA Subtitle C requirements for hazardous waste
landfills. The bottom liner system of the CAMU consists of a low-permeability geosynthetic
clay liner liners, a geonet leachate
collection layer, and a leachate collection sump. The CAMU will be covered to prevent
exposure of contaminants to the elements and to minimize the infiltration of precipitation. The
cover will consist of a 40 mil HDPE geomembrane. a geonet collection layer, and a
separation/filtration geotextile. The cover also will be secured with 18 inches of clean, graded
soil, six inches of topsoil. and a stone protection toe-drain. The treatment method for
contaminated soils temporarily stockpiled in the CAMU will be specified in the final soils OU
ROD.
The Soil Repository has been constructed to meet RCRA Subtitle C requirements tor
hazardous waste landfills. The bottom liner system includes a low-permeability GCL and two
60 mil HDPE liners to eliminate the potential migration of contaminants to underlying soils
and groundwater. The bottom liner also includes a geocomposite drainage layer for leak
detection and additional drainage and leachate collection features. The Soil Repository will be
covered by an extension of the cover to be placed on the Inert Landfill after the trench has
been filled, but will include an underlying GCL to further improve performance.
The Army began activities to construct a low permeability cover on the 17-acre Inert Landfill
site in the fall of 1996. The cover will include a geonet drainage layer and a 40 mil HDPE
liner. The cover system will prevent infiltration of precipitation into the landfill material and
the subsequent transport of contaminants from wastes to groundwater.
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8.0 Summary of Comparative Analysis of Alternatives
This section evaluates the performance of the three alternatives relative to the nine criteria
established in the NCP. The purpose of this analysis is to identify the relative advantages and
disadvantages of each alternative.
The first step of this analysis is to ensure that the alternative satisfies the threshold criteria
established in the NCP. The two threshold criteria are: 1) overall protection of public health
and the environment, and 2) compliance with applicable or relevant and appropriate
\
requirements (ARAR). In general, alternatives that do not satisfy these two criteria are
rejected and not evaluated further. However, compliance with ARARs may be "waived" if
site-specific circumstances warrant such a waiver as described in Section 300.430(f)(l)(ii)(C)
of the NCP.
The second step is to compare the alternative against a set of balancing criteria. The NCP
establishes the following five balancing criteria:
1) long-term effectiveness and permanence
2) reduction in toxiciry, mobility, or volume achieved through treatment
3) implementabiliry
4) short-term effectiveness
5) cost
The third and final step of the analysis is to evaluate the alternative on the basis of the NCP
modifying criteria. The two modifying criteria are: state and community acceptance. These
final two criteria cannot be evaluated fully until the state and public have commented on the
alternatives and their comments have been analyzed.
8.1 Overall Protection of Human Health and the Environment
All of the alternatives evaluated would satisfy the threshold criterion of protecting human
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health and the environment. Each alternative would utilize the same remediation goals to
achieve the remedial action objectives, and would thereby achieve the same level of
protectiveness. Alternatives I and 2 would utilize treatment to attain the cleanup objectives,
while Alternative 3 would employ a combination ot containment and treatment to achieve these
objectives. For Alternative 3. a smaller volume of contaminated soils would be treated
relative to Alternatives 1 and 2. This treatment would not be accomplished as a pan of this
action, but would be specified as a pan of the final soils OU ROD.
8.2 Compliance with Applicable or Relevant and Appropriate Requirements
All of the alternatives considered would comply with the respective ARARs of federal and
State of Iowa environmental laws. These ARARs. and a summary indicating how the
alternatives attain compliance with identified ARARs. are presented in Appendix A of the
IAAAP FFS for the soils OU. Alternative 3 complies with RCRA LDRs by utilizing a CAMU
for temporary management of the most highly contaminated soils excavated from the 15
remediation areas. Treatment of these highly contaminated soils will ultimately be required to
satisfy LDRs.
In addition, EPA has evaluated whether contaminated soils at the sub-sites addressed in this
Interim ROD contain hazardous waste. This determines whether the RCRA LDRs (40 CFR
pan 268) would be applicable to the management of the contaminated soil.
EPA's "contained-in" policy regarding the management of environmental media, such as soil,
which has been contaminated with RCRA hazardous waste addresses this issue. The soil itself
is not considered hazardous but is managed as hazardous waste under RCRA Subtitle C
regulations because it contains hazardous waste. At some point, soil that has been
contaminated with hazardous waste is no longer considered to contain hazardous waste. Upon
this determination, the soil no longer needs to be managed as RCRA regulated waste. The
point at which this occurs or may be determined is dependent on whether the hazardous waste
contaminating the soil is a characteristic hazardous waste or a listed hazardous waste.
Soil, which is contaminated with characteristic hazardous waste, is regulated under RCRA
Subtitle C onlv if the contaminated soil exhibits a hazardous waste characteristic, such as
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'toxicity" for example. For such potentially "tcxic" characteristic wastes, this means that the
waste contaminated soil is not regulated as RCRA hazardous waste unless TCLP analysis
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CFR § 261.32. pink/red water from TNT operations is included in the RCRA List of
Hazardous Wastes from Specific Sources as K047. K047 waste is a listed hazardous waste. It
is listed as RCRA hazardous solely on the basis of the characteristic of reactivity (See 40 CFR
§261.30 and §261.32).
The Army has sampled the soils at the above-listed sub-sites and found that, even though the
soils are contaminated with TNT. they do not exhibit the characteristic of reactivity.
In cases where the waste is listed only for reactivity, and the contaminated soil is not reactive
and does not exhibit any other characteristics, the contaminated soil may contain hazardous
'constituents" and thereby contain the listed waste. Consistent with the contained-in policy
previously outlined, an authorized state or EPA may establish health-based levels for any
hazardous constituents present in the contaminated soil below which the contaminated soil
would no longer contain the listed waste.
K047 is listed as a hazardous waste solely due to the characteristic of reactivity. No hazardous
constituents are identified in Appendix VII to Part 261 as a basis for listing K047 as a
hazardous waste.
Also there are no hazardous constituents for K047 identified in the LDR treatment standards
provisions at 40 CFR § 268.40 ff. The only treatment standard identified for K047 waste is
technology based-deactivation (40 CFR § 268.42). According to the tests conducted to date
on soil samples from the various LAP sites, the soils are already "deactivated" because they do
not exhibit the characteristic of reactivity.
Other possible explosive contaminants and degradation products, which may be present in the
soils, include: high melting explosive (HMX); RDX; 2,4,6-TNT; 1,3,5-TNB; 2,4-
Dinitrotoluene (DNT) (D030); Nitrobenzene (NBO (D036); 1,3-dinitobenzene (DNB); and 2,6-
dinitrotoluene (DNT). The first three, HMX, RDX, and 2.4,6-TNT, are not identified as
Hazardous Constituents in Appendix VIII to Part 261 of RCRA and therefore, do not need to
be considered in making a "contained-out" determination. The latter five contaminants are
identified as Appendix VIII Hazardous Constituents. These are the five constituents, which
29
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must be considered in making a determination that the excavated soil no longer contains K047
Listed Hazardous Waste.
Two other explosive contaminants, which might be present in soils contaminated by pink/red
water from TNT operations at concentrations that would make them RCRA characteristic
hazardous waste due to the toxicity characteristic, are 2.4-DNT (EPA HW No. D030) and NB
(EPA HW No. D036). Alternative 3 proposes to conduct additional sampling to evaluate the
presence of these potentially characteristic hazardous wastes during the excavation of the soils.
Alternative 3 specifies that the excavated contaminated soil be segregated according to
cumulative risk levels. Soils which are above a risk level of 103 (based on the site-specific
risk assessment), exhibit a characteristic, or exceed the LDR treatment standards, will be
stockpiled in a RCRA temporary stockpile tor eventual treatment which will be determined in
a subsequent ROD. Soil between the 10'3 and 10 " risk levels will be disposed of in the on-
site Soil Repository. Soil below the 10'" risk level and above the Summers Model soil-to-
groundwater 'leaching action level will be placed in either the Soil Repository or under the
cap proposed for the Inert Landfill.
EPA has determined that soils which are below the 10"5 cumulative risk level, do not exhibit
any RCRA characteristics (reactivity or toxicity), and do not exceed LDR levels, when
managed appropriately, do not pose a substantial threat to human health and the environment.
Therefore these soils should not be considered to contain RCRA hazardous waste and as such,
would not require management as RCRA hazardous waste.
Alternative 3 anticipates the possibility that some excavated soil might exhibit a characteristic
such as reactivity or contain 2,4-DNT (D030) or NB (D036) at concentrations making them
Toxicity Characteristic hazardous wastes subject to RCRA regulation. Since soil containing
such hazardous wastes would be sent to the stockpile for storage, the temporary stockpile
would be subject to LDR unless designated by EPA as a CAMU. Such a CAMU designation
was made by EPA in a memorandum entitled "Designation of CAMU, IAAAP Site,
Middletown, Iowa, dated March 8. 1995.
Soils from other IAAAP sub-sites addressed by Alternative 3. including Lines 4A. 4B, 6, 8,
30
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and 9. the EDA-East Burn Pads, the Demolition Area, the West Burn Cages/Burn Pads, the
North Burn Pads, and the Roundhouse Transformer storage area do not contain RCRA listed
wastes, but may be contaminated at levels which constitute a characteristic waste. Alternative
3 requires that the soils from all areas addressed by this Interim Action be evaluated for
possible RCRA characteristics so that the soils are managed consistent with LDRs.
8.3 Long-Term Effectiveness and Permanence
Alternative 1 provides the highest degree of permanence, as the majority of the contaminants
would be permanently destroyed via incineration. Alternative 2 provides permanence by
utilizing composting 10 stabilize explosives-contaminated soils in combination with long-term
management of the treatment residuals. The degree to which composting may be considered a
long-term irreversible process for stabilizing explosives-contaminated soils requires additional
evaluation through pilot testing. Alternative 3 provides for effective containment of
contaminated soils by utilizing conservative landfill design measures. These measures, when
combined with treatment of the contaminated soils as part of the final remedy, will provide for
permanent, significant contaminant reduction of the principal threat. Alternatives 2 and 3 rely
on adequate maintenance of the CAMU and Soil Repository to ensure long-term effectiveness
in the management of treatment residuals and remediation wastes.
8.4 Reduction in Toxicity, Mobility, or Volume Through Treatment
The alternatives evaluated utilize treatment to reduce contaminant toxicity, mobility, or volume
in varying degrees. Alternative 1 utilizes incineration to permanently destroy the toxicity and
mobility of the COCs. Alternative 2 reduces the toxicity and mobility of contaminants via
stabilization/ composting, but actually increases the volume of the contaminated media.
Alternative 3 specifies containment for permanent disposal of lesser contaminated materials,
while more highly contaminated materials posing the principal threat are temporarily stored
pending the final soils OU ROD. Alternative 3, in conjunction with the final remedy for the
site, proposes to utilize treatment to reduce the toxicity and mobility of the soils posing the
principal threat.
31
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8.5 Short-Term Effectiveness
Each of the alternatives requires excavation and ex-sim management of contaminated soils.
Short-term risks associated with Alternative 3 are attributed to such excavation and subsequent
transport of these soils to the on-site management facilities. Alternatives 1 and 2 specify
additional handling of the soils to accomplish treatment objectives. Risks associated with
emissions due to incineration specified by Alternative 1 will be managed by emission
abatement technologies. It would be necessary to demonstrate to the local community the
effectiveness of the emissions control equipment.
8.6 Implementability
Alternative 3 is the most readily implementable alternative, as the on-site containment
structures have been constructed as a component of other response actions at the site and are
presently available to receive contaminated material. Alternatives 1 and 2 are implementable.
but would require construction of treatment facilities. The time frame to implement
Alternative 3 would be less than either Alternatives 1 or 2. which are estimated at 1.5 to 2
years for completion. Each of the alternatives will require coordination with IAAAP
operations to ensure that access is available to the areas of concern and to ensure that conflicts
with IAAAP production schedules are minimized.
8.7 Cost
Costs to implement each alternative, as estimated in Sections 3.4.1 - 3.4.3 of the FFS, are as
follows:
Alternative 1: $24,086,000 (see Table 4)
Alternative 2: 526,408.000 (see Table 5)
Alternatives: 52,513,000 (see Table 6)
32
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-oilowmsz me FFS ana Proposed P!an. hut concurrent \virn me writing or this ROD. Additional
mormation regarding implementation costs nave hecome available to the Army. This
niormatton is a haseu on costs associated ^ith cn-iioinn removal actions at the Line 1
':nrjounument and Line .>')() ['ink VN ater Lagoon >uo-Mtes ai iAAAP. 'Ahich are discussed in
Section 2.0 of this ROD. \s a result ot this information, the cost estimates developed in the
FFS have been re-evaluated. Additional costs of approximateiy 57.000.000 have been round
:o be required to implement each or the alternatives considered. For Alternative 3. an
additional S2.000.000 would be required tor operations and maintenance activities over a
presumed 30- year lifetime. Thus, revised comparative cost estimates, including capital and
operations
-------
S.9 Community Acceptance
Community acceptance or the selected alternative is assessed in this ROD. No public comments
were submitted to the Army during the public comment period, which was held May 22. 1997 to
June 21, 1997. In addition, no members of the public attended the public meeting on the
Proposed Plan held at the Danville Community Center on June 5. 1997. Based on the nature of
the public response, the preferred alternative identified in the Proposed Plan is acceptable to the
community.
9.0 Selected Remedy
Based on information included in the Administrative Record, and criteria set forth in
CERCLA/ SARA and the NCP. the Army, with support from EPA. has selected Alternative 3
as the alternative to address soil contamination as an Interim Action for the IAAAP soils OU.
9.1 Major Components
The selected interim remedy consists of the following primary elements:
1. Excavation of soils contaminated at levels exceeding RGs from the 15 remediation
areas noted in Table 1.
2. Verification sampling to ensure that RGs are met in the 15 remediation areas.
Restoration of excavated areas to original conditions.
3. Segregation of the excavated soils according to contaminant type and concentration.
4. Temporary storage of the most highly contaminated soils in the on-site CAMU.
Treatment of soils stored in the CAMU as specified in die final ROD for the soils OU.
5. Permanent disposal of soils contaminated at lesser levels in the on-site Soil Repository
or in the on-site Inert Landfill.
6. Solidification/stabilization of metals-contaminated soils at levels exceeding LDR
criteria, and permanent disposal in die on-site Soil Repository.
During the remedial design phase, additional sampling will be performed in the areas to be
34
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remediated to ensure that the extent of contamination is completely defined.
Since this is an interim action, several elements or the final remedy have been deferred to the
final ROD for the soils OU. These would include long-term actions such as institutional
controls to restrict access and land usage at the Inert Landfill Area and to restrict remediated
areas to commercial / industrial land usage in the future, consistent with the cleanup goals. In
addition, the final remedy for the soils OU will specify a long-term monitoring plan for the
Inert Landfill Area to monitor the performance and integrity of the Soil Repository and the
Inert Landfill, and will specify means by which the CAMU will be ultimately closed.
l).2 Remediation Goals
Remediation goals for the IAAAP have been established based on risk considerations (see
Table 2). These include criteria associated with ingestion of and dermal contact with
contaminated soils by the reasonably maximum exposed individual, as well as criteria to
evaluate possible leaching of contaminants from soils to groundwater at unacceptable levels.
For the IAAAP. RGs were established at a target carcinogenic risk of 10°. consistent with the
NCP. The NCP states that RGs should be established for individual constituents within the
risk range of 10"4 to 10'*, with a preference for the most protective values.
Commercial/industrial land use is the current and reasonably anticipated future land use at the
site upon which the RGs have been based. RGs for additional constituents which may be
detected at levels of concern subsequent to the RI. such as during pre-design sampling
activities, will be determined using the method which was used to determine the RGs for
constituents in Table 2. This method is outlined in detail in the FFS.
In addition to risk-based soil RGs for protection of human health, the impact to groundwater
from residual soil contamination was evaluated. The Summers' model was utilized to estimate
the level at which contaminant concentrations in soils will produce groundwater contamination
at concentrations above acceptable levels.
The Summers' model assumes that a percentage of rainfall at the site will infiltrate the surface
and desorb contaminants from soils, based on an equilibrium of soil and water partitioning. It
is further assumed that this contaminated infiltration will mix completely with the groundwater
35
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below the site, resulting in an equilibrium groundwater concentration with all contaminants in
the final mixture ttom the infiltration.
The Summers' model was used to determine acceptable levels tor the explosives RDX and
2.4.6-TNT in soils, which are found in on- and off-site groundwater. The model was not
used for metals, as metals are relatively immobile in the clay soils found at the IAAAP.
Further. TNT and RDX are the most prevalent and most mobile contaminants found at the
site. The site-specific 'leaching" RGs for these major contributing explosives are presented in
Table 3. These RGs represent contaminant levels in soils that are considered protective of
human health and protective of groundwater. These values are utilized as the RGs for RDX
and 2.4.6-TNT. superseding the values presented in Table 2 which are based solely on soil
ingestion and dermal contact criteria.
9.3 Cost
The cost for the selected remedy. Alternative 3. is summarized in the FFS and in Sections 8.7
and 11.0 of this ROD. The basis of the estimate is as follows:
1. Excavate 42.742 yd3 of contaminated soils, transport to an on-site treatment area.
backfill and compact excavation. Assumed unit cost is $25.50/yd3.
2. Solidification/stabilization of soils from Group E. The unit cost is calculated based on
a typical range of S50/yd3 to $l70/yd3. Because there is no indication that the soils
have any particular characteristics that may make them either unsuitable or more
suitable to solidification/stabilization, a unit cost of $154/yd3 is assumed for this
process.
3. For cost estimating purposes, and because the volume of soils in Group E is not
known, it has been assumed that soils with lead concentrations above 2,000 ppm will
undergo solidification/stabilization. Based on the data presented in Appendix D of the
IAAAP FFS for the soils OU, the amount of soils that will require stabilization is
estimated at 3,860 yd3.
4. Analytical costs will be incurred in order to verify the extent of excavation in each
area. It has been assumed that an average of eight soil samples per area will be taken
and analyzed for explosives and metals.
36
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The total cost of implementation tor Alternative 3. including capital and operations &
maintenance costs is estimated at Si 1.532.000.
10.0 Statutory Determinations
»
In accordance with the statutory requirements or Section 121 of CERCLA, remedial actions that
are selected are required to:
Protect human health and the environment
Comply with applicable or relevant and appropriate requirements < ARARs)
Be cost effective
Use permanent solutions and alternative treatment technologies to the maximum
extent practicable
Satisfy the preference for treatment that reduces contaminant toxicity, mobility, or
volume as a principal element
The manner in which the IAAAP soils OU interim remedial action satisfies the above
requirements is discussed in the following sections.
The selected remedy will be reviewed, at a minimum, every five years as specified in CERCLA
121(c) because hazardous substances will remain on-site after the remedy is implemented.
10.1 Protection of Human Health and the Environment
The selected remedy will meet the remediation goals and remedial action objectives for the
Interim Action by preventing human contact with contaminants of concern in soils at levels
posing a threat, and by minimizing potential impacts associated with contaminants leaching
from soils to groundwater. Contaminated soils will be managed according to the risks posed.
37
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Low- to mid-level contaminated soils posing unacceptable human health risks will be
permanently contained in the on-site Soil Repository or under the Inert Landfill cap. The most
highly contaminated soils will he temporarily contained in the on-site CAMU. and will be
treated to reduce contaminant toxictiy, mobility, or volume at a date consistent with the final
action tor the IAAAP soils OU. Remediation goals tor contaminants of concern at the IAAAP
have been established based upon the most protective of the following criteria: a carcinogenic
risk of 10"". a hazard index of 1. or on the leachability of contaminants from soil to
groundwater. Maintenance of the containment structures will determine the effectiveness and
permanence of the selected remedy. A five-year review will be performed following
implementation of the selected remedy to ensure that the principal threats to human health and
(he environment are addressed. The five-year review is required to document that the interim
remedial action has effectively minimized the potential for human exposure to contamination
and has eliminated the contributions of the 15 areas addressed in this Interim ROD to shallow
groundwater contamination.
10.2 Compliance with Applicable or Relevant and Appropriate Requirements
The selected remedy will comply with all ARARs that are location, chemical, and action
specific. The ARARs are presented below.
10.2.1 Location-Specific ARARs
Applicable
Endangered Species Act, 16 U.S.C. 1531 el seq., and Fish and Wildlife Coordination Act,
16U.S.C. 661 et seq.
Bald Eagle Protection Act. 16 U.S.C. 668 et seq.
Migratory Bird Treaty Act of 1972, 16 U.S.C. Section 703
National Archeological and Historical Preservation Act, 16 U.S.C. Section 469
Native American Graves and Repatriation Act, 25 U.S.C. Section 3001
Fish and Wildlife Coordination Act, 16 U.S.C. 661 et seq.
I.A.C., Title XI, Natural Resources; Subtitle 6, Wildlife; Chapter 481A, Wildlife
Conservation
38
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10.2.2 Chemical-Specific ARARs
Applicable
Soils
TSCA. 15 U.S.C. 2601 ei seq. |PCB spill cleanup policy)
Air
IEQA. I.A.C.. Division 567. Title II. Chapter 28. Ambient Air Quality Standards
(Ambient
Air Quality Standards)
I.EQA. I.A.C.. Division 567. Title II. Chapter 23. Emission Standards for Contaminants
[Emission Standard tor Fugitive Dust|
Surface Water
FWPCA. 33 U.S.C. Section 402 [NPDES permit)
IEQA. I.A.C.. Division 567. Title III. Chapter 62. Effluent and Pretreatment Standards:
Other Effluent Limitations or Prohibitions [NPDES permitj
IEQA. I.A.C.. Division 567. Title IV. Chapter 61. Surface Water Quality Criteria [anti-
degradation policy: water quality criteria]
Groundwater
Solid Waste Disposal Act, as amended by RCRA, 42 U.S.C. 6901 et seq. [groundwater
protection standards for permitted hazardous waste facilities]
Relevant and Appropriate
Soils
Iowa Underground Storage Tanks Acts, I.A.C., Division 567, Title X, Chapter 135, Iowa
Underground Storage Tanks Regulations [levels of corrective action for petroleum
contamination]
39
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Surface Water
SDWA. 42 U.S.C. 300 ei seq. (VICLs: MCLGs]
EPA. Office of Water. Drinking Water Regulations and Health Advisories." October
1996 [MCLsl
1EQA, I.A.C.. Division 567. Title III. Chapter 41. Iowa Drinking Water Regulations
[MCLs]
Groundwater
SDWA. 42 U.S.C. 300 et seq. [MCLs: MCLGs]
EPA. Office of Water. Drinking Water Regulations and Health Advisories." October
1996 (MCLs)
Solid Waste Disposal Act. as amended by RCRA. 42 U.S.C. 6901 et seq. [groundwater
protection standards for solid waste disposal facilitiesj
IEQA. I.A.C.. Division 567. Title III. Chapter 41, Iowa Drinking Water Regulations
[MCLsj
To-Be-Considered
Soils
Proposed Rule. 55 Federal Register, July 27. 1990, "Corrective Action for Solid Waste
Management Units (SWMUs) at Hazardous Waste Management Facilities," Appendix A -
Examples of Concentrations Meeting Criteria for Action Levels [proposed soil action
levels]
EPA, OSWER Directive 9355.4-02, September 7, 1989, "Interim Guidance on
Establishing Soil Lead Cleanup Levels at Superfund Sites" [soil lead cleanup guidance
levels]
EPA, OSWER Publication 9285.7-01B, December 1991, "Risk Assessment Guidance for
Superfund: Volume I - Human Health Evaluation Manual (Part B, Development of Risk-
based Preliminary Remediation Goals"
Surface Water
EPA, Office of Water. "Drinking Water Regulations and Health Advisories," October
1996 [proposed MCLs and proposed MCLGs]
40
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Groundwater
EPA. Office of Water. Drinking Water Regulations and Health Advisories." October
1996 [proposed MCLs and proposed MCLGs|
10.2.3 Action-Specific ARARs
Applicable
TSCA. 15 U.S.C. 2601 et seq. [PCB disposal requirements)
Relevant and Appropriate
Solid Waste Disposal Act. as amended by RCRA. 42 U.S.C. 6901 ei seq. [LDRs]
IEQA. I.A.C.. Division 567. Title X. Chapter 141. Hazardous Waste, adoption of 40 CFR
261.21-261.24 and Table 1 (criteria for identifying the characteristics of RCRA hazardous
wastes]
IEQA. I.A.C.. Division 567, Title X. Chapter 141. Hazardous Waste, adoption of 40 CFR
261.32 [criteria for listing RCRA hazardous wastes)
IEQA, I.A.C., Division 567. Title X. Chapter 141, adoption of 40 CFR 264.14 [security
requirements)
IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR 264.17(a) and (b)
[general requirements for ignitable, reactive, or incompatible wastes]
IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR Part 264, Subpart
F [requirements for groundwater protection for land disposal units]
IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR Pan 264, Subpart
G [closure and post-closure requirements]
- IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR Pan 264, Subpart
I [requirements for use and management of containers]
IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR Part 264, Subpart
L [requirements for storage of hazardous waste in piles]
IEQA, I.A.C., Division 567, Title X, Chapter 141, adoption of 40 CFR Part 264, Subpart
N [requirements for disposal of hazardous waste in landfills]
IEQA, I.A.C., Division 567, Title X. Chapter 141, adoption of 40 CFR Pan 264, Subpan
41
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S [corrective action tor solid waste management units)
1EQA, I.A.C.. Division 567. Title II. Chapter 23. Emission Standards tor Contaminants
[fugitive dust controls)
To-Be-Considered
EPA. OSWER Directive 9347.3-06FS. July 1989. "Obtaining a Soil and Debris
Treatability Variance tor Remedial Actions" [treatability variance process to comply with
LDRs)
10.3 Cost-Effectiveness
The selected remedy will provide overall effectiveness and protection of human health and the
environment proportional to its costs. The selected remedy will effectively eliminate
unacceptable risks to human health and the environment, at an estimated cost of SI 1,532,000,
which is approximately 60% less costly than the other alternatives considered. The remedy
specifies containment of low-level threat material, with storage and ultimate treatment of the
high-level or principal threat material. The approach of treating only the principal threat
material reduces the cost of the selected alternative significantly relative to other alternatives
considered, where treatment of the entire volume of contaminated soil is evaluated. Based on
estimates in the FFS. the combination of containment and treatment will provide for treatment
of approximately 70% of the total contaminant mass by treating less than 10% of the
contaminated soil volume. The selected remedy utilizes existing facilities at the IAAAP to the
maximum extent practical to achieve significant cost advantages.
10.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
(or Resource Recovery Technologies) to the Maximum Extent Practicable
The selected remedy meets the statutory requirement to utilize permanent solutions and
treatment technologies to the maximum extent practicable. The selected remedy provides the
best balance of tradeoffs among alternatives, which are protective and ARAR-compliant
relative to the five primary balancing criteria. These balancing criteria are:
42
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- Long-term effectiveness and permanence
- Reduction ot'toxicity. mobility, or volume through treatment
- Short-term effectiveness
- Implementability
- Cost
The selected remedy utilizes a combination of containment and treatment technologies to
address unacceptable risks. The most highly contaminated soils will be temporarily stored in a
secure containment structure that will effectively eliminate potential human exposures and
minimize the migration of contaminants. It is estimated that six percent of the total volume of
contaminated soils to be addressed by this interim action, or a total of approximately 2500 yd3
of soils, will be stored in the CAMU in the implementation of the selected remedy. Nearly 70
percent of the total contaminant mass addressed by the selected remedy is contained in this
volume. Treatment of the most highly contaminated soils provides a cost-effective and
permanent approach to mitigate the principal threat. Moderately contaminated soils will be
permanently disposed in the on-site Soil Repository and under the cap or the Inert Landfill.
Several of the balancing criteria were critical in selecting Alternative 3 for this interim action.
Cost / cost-effectiveness was a significant consideration. Estimated costs to implement
Alternative 3 were approximately 60% less costly than the other alternatives considered.
Although additional costs associated with the treatment of soils temporarily managed in the
CAMU will be incurred to complete Alternative 3, these costs would be anticipated to be
relatively small due to the minimal total volume of CAMU material. Costs associated with
this treatment may approach $1.250.000 (assumes 2500 yd3 of soil to be treated at a cost of
$500/ ydj). The reduced volume of soil to be treated in Alternative 3 provides for treatment
of approximately 70% of the total contaminant mass by stockpiling and treating only the most
contaminated soil. Thus the statutory preference for reduction in contaminant toxicity,
mobility, or volume through treatment is adequately addressed in Alternative 3, with
significant cost benefits. Long-term effectiveness and permanence is addressed in Alternative
3, as the containment structures are constructed with liner systems consisting of several
synthetic hydraulic barriers and are also equipped with leachate collection systems.
Alternative 3 is the most implementable of the alternatives considered, as facilities currently
available at the IAAAP are utilized fully.
43
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During the public comment period, the community did not identify any concerns regarding the
selected remedy.
A review of the selected remedy will be performed since the selected remedy will require
management of contaminated soils on-site. The review will be conducted no less often than
every five years after commencement of the remedial action to ensure the remedy continues to
provide adequate protection of human health and the environment.
10.5 Preference For Treatment as a Principal Element
For this site, soils contaminated at carcinogenic risk levels exceeding 10'5 have been
considered to act as a principal threat. This consideration is primarily based on the toxicity
and mobility of the explosives found at the site, which are the predominant contaminants of
concern in soil and groundwater at the IAAAP. Soils contaminated with explosives at risk
levels near 10"8 may leach contaminants to groundwater at unacceptable levels. These
explosives have been found in groundwater supply wells off-site at levels of concern. The
soils which are contaminated at levels which constitute a principal threat will not be treated as
a component of this interim action, but will be temporarily stored in the CAMU and will
ultimately be treated to reduce the contaminant toxicity, mobility, or volume to satisfy
requirements of CERCLA Section 121(b). The nature of this treatment will be specified in the
final soils OU ROD according to the schedule and procedures outlined in the IAAAP FFA.
11.0 Documentation of Significant Changes
As discussed in section 8.7 of this ROD, the Army has utilized additional information to
provide updated estimates of the costs associated with the implementation of each of the
interim actions considered in the FFS and Proposed Plan. These revised estimates add
approximately $7.000,000 to the cost of each alternative evaluated, with an additional
52.000,000 added to the estimate for Alternative 3 associated with operations and
maintenance. The basis for these additional costs are summarized in Table 7, 8, 9, and 10.
Operations and maintenance costs for Alternative 3 were not included in the original costs
44
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estimates in the FFS. O&M costs are estimated here assuming a 30 year operational lifetime
and an interest rate of 7^ to determine the net present worth associated with annual operations
and maintenance.
These revised cost estimates have been reflected in Sections 8.7 and 9.3 of this ROD. The
revised cost estimates do not effect the comparison of alternatives conducted in the Proposed
Plan and do not warrant a re-evaluation of the interim action selected. While the revised cost
estimates are a significant change to the information presented in the Proposed Plan, the
revised cost estimates will not require additional public notice or comment per EPA Guidance
("Guide to Addressing Pre-ROD and Post-ROD Changes" - Publication 9355.3-02FS-4).
12.0 Responsiveness Summary
The final component of the ROD is the Responsiveness Summary. The Responsiveness
Summary provides a summary of the public's comments, concerns, and questions received
concerning the selected interim remedial action for contaminated soils at 15 areas throughout
the 1AAAP.
12.1 Overview
At the time of the public comment period, the Army had endorsed a preferred alternative for
the interim remedial action for contaminated soils at 15 areas throughout the IAAAP.
lAAAP's selected alternative was excavation of all contaminated soils, segregation of soils
based on risk levels and contaminant type, management of those soils in the existing IAAAP
landfills, including the CAMU, the Soils Repository, and the Inert Landfill, and
olidification/stabilization of soils that fail LDR criteria.
The Army has coordinated selection of this interim remedial action with EPA. The Army is
the lead agency for implementing the interim remedial action at the IAAAP. As the support
agency, the EPA oversees the cleanup activities conducted by the Army to ensure that
requirements of CERCLA/SARA, the NCP, and the Federal Facilities Agreement between the
Army and the EPA have been met. EPA concurs with the selected remedy. The state of
Iowa has not participated in the review of CERCLA clean up activities at the IAAAP and has
45
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declined to comment upon the prererred alternative presented in the Proposed Plan for this
Interim Remedial Action.
12.2 Community Involvement
The RI/FS and Proposed Plan tor the soils OU were released to the public in November 1996
and May 1997. respectively. These documents were made available to the public in both the
administrative record and the site information repositories. The notice of availability for the
Proposed Plan was published in the Burlington-Hawkeye on May 21. 1997. The
Administrative Record is available for review during normal business hours at the IAAAP,
Visitor Reception Area. Building 100-101: the Burlington Public Library: and the Danville
City Hall. A public comment period was held from May 22. 1997 to June 21, 1997. In
addition, a public meeting was held on June 5. 1997 at the Danville Community Center. At
this meeting representatives from the Army and EPA were available to the public to discuss
concerns, accept comments, and answer questions regarding the preferred alternative presented
in the Proposed Plan. There were no written or verbal comments regarding the Proposed Plan
submitted to the Army at this meeting or during the comment period.
46
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TABLES
47
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TABLE 1
Site
Line 1
'ROD
Line 2
|R02)
Line 3
Lines 4A &
4B (R05)
Lines 5A &
58 (R06)
Line 6
(R07)
Line 8
Line 9
(RIO)
Line 800
(RID
EDA/East
Bum Pads
(R12)
Demolition
Area
Burn Cages/
West Burn
Pads Area
(R24)
North Burn
Pads (R25)
Roundhouse
Transformer
Storage
Area (R28)
TOTAL
Metals
219
885
.M6
153
SO
445
476
469
!17
753
423
41
4.607
Explosives
4.853
769
1.884
1.352
626
1.208
21.411
339
32.442
i Metals/
Explosives
1.486
294
835
684
25
689
4.013
SVOC
s
587
587
Radio-
nuclide
s
256
119
385
Explosiv
es/
SVOCs
109
109
PCB
s
599
F599
TOTA
L
7.411
1,948
3.493
2,036
153
731
445
476
469
1,325
21.411
753
1,451
41
599
42.742
48
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TABLE 2
Soil Remediation Goals:
Human Health
Chemical
Antimony
Arsenic
Beryllium
Cadmium
Chromium V!
Lead
Thallium
Benzo
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TABLE 4
Alternative 1: Cost Estimate from FFS
Activuv
Earth Moving
Excavation and transport to
treatment facility. Backfill
and compact excavation.
Treatment
Incineration
Sol idification/stabil ization
Subtotal
Analytical: 122 sites. 8 samples/site
Subtotal
Contingency (20%)
Total
Unit
yd3
yd'
yd'
sample
Quantity
42,742
37.750
4.607
976
Unit Cost
$25.50
$473.20
$154.00
$420.00
Cost
$1.090,000
$17,863,000
$709,000
$18,572,000
$410,000
$20.072,000
$4.014,000
$24.086.000
TABLES
Alternative 2: Cost Estimate from FFS
Activity
Earth Moving
Excavation &. transport to
treatment facility. Backfill
and compact excavation.
Treatment
Bioremediation/composting
Solidification/Stabilization
Subtotal
Analytical: 122 sites, 8
Subtotal
Contingency (20%)
Total
Unit
yd1
yd3
yd3
sample
Quantity
42,742
37,143
13,018
976
Unit Cost
$25.50
$498.13
$154.00
$420.00
Cost
$1,090,000
$18,502.000
$2,005.000
$20,507,000
$410,000
$22,007,000
$4,401.000
$26,408,000
50
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TABLE 6
Alternative 3: Cost Estimate from FFS
Activitv
Earth Moving
Excavation and transport to
treatment facility. Backfill
and compact excavation.
Treatment
Solidification/stabilization
Analytical: 122 sites. 8 samples/site
Subtotal
Contingency (20%)
Total
Unit
yd1
yd3
sample
Quantity
42,742
3,860
976
Unit Cost
$25.50
Cost
$1,090,000
$154.00 1 $594,000
$420.00| $410,000
$2,094,000
$419.000
$2.513.000
51
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TABLE?
Alternative 1: Revised Cost Estimate
Activity
Eartb Moving
Excavation and transport to treatment facility.
Backfill and compact excavation.
Treatment
Incineration
Solidification/stabilization
Analytical: 122 sices, 8 samples/site
Support Activities - Preparation of Health and Safety
Plans. Sampling and Analysis Plans, Quality Assurance
Plans. Work Plans. Scheduling. Revisions to Work Plans.
Project management costs.
Sampling and analytical costs for establishing actual
extent of contamination.
Utility identification, avoidance, and relocation.
Environmental mitigation of cultural resources at the East
Bum Pads area.
Suifece water control and treatment.
Construction of decontamination pads.
Borrow source development and reclamation.
Monitoring well abandonment and relocation.
Site restoration activities.
Road repair and maintenance
Subtotal
Contingency (20%)
Total Revised Cost for Alternative 1
Unit
yd1
yd1
yd1
sample
Quantity Unit Cost
42,742
37,750
4,607
976
$25.50
$473.20
$154.00
$420.00
Cost
$1,090,000.00
S17.863.000.00
S709.000.00
S410.000.00
$2,000,000.00
$1, 000,000.00
S200.000.00
$100.000.00
$500.000.00
$250.000.00
$500.000.00
$200.000.00
$150.000.00
$1.000.000.00
$25,972.000.00
$5.194,400.00
$31,166,400.00
52
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TABLES
Alternative 2: Revised Cost Estimate
Excavation and transport to treatment facility. Backfill
and compact excavation.
SI. 090.000.00
S17.863.000.00
Solidification/stabilization
Analytical: 122 sites. 8 samples/site
S2.000.000.00
Support Activities Preparation of Health and Safety Plans.
Sampling and Analysis Plans. Quality Assurance Plans. Work
Plans. Scheduling. Revisions to Work Plans. Project
management costs.
$1.000.000.00
Sampling and analytical costs for establishing actual extent of
contamination.
Utility identification, avoidance, and relocation.
Environmental mitigation of cultural resources at the East Bum
Pads area.
Surface water control and treatment.
Construction of decontamination pads.
Borrow source development and reclamation.
Monitoring well abandonment and relocation
Site restoration activities.
$150.000.00
$27.907.000.00
Road repair and main
S5.581.400.00
Contingency (20%)
Total Revised Cost for Alternative 2
53
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TABLE 9
Alternative 3: Revised Capital Cost Estimate
Activity
Earth Moving
Excavation and transport to treatment facility.
Backfill and compact excavation.
Treatment
Solidification/stabilization
Analytical: 122 sites. 8 samples/site
GAC system hardware and installation
Support Activities - Preparation or Health and Safety Plans.
Sampling and Analysis Plans. Quality Assurance Plans. Work
Plans. Scheduling, Revisions to Work Plans. Project
management costs.
Sampling and analytical costs for establishing actual extent of
contamination.
Utility identification, avoidance, and relocation.
Environmental mitigation of cultural resources at the East Bum
Pads area.
Surface water control and treatment.
Construction of decontamination pads.
Borrow source development and reclamation.
Monitoring well abandonment and relocation.
Site restoration activities.
Pnad igpair *nit m«t»it»f»«iw»
Subtotal
Contingency (20%)
Tool Revised Capital Cost for Alternative 3
Unit
*
y*
sample
Quantity
42.742
3.860
976
Unit Cost
S25.50
$154.00
$420.00
Cost
SI. 090.000.00
S594.000.00
S410.000.00
S500.000.00
S2.000.000.00
SI. 000.000.00
S200.000.00
S100.000.00
S500.000.00
S250.000.00
S500.000.00
S200.000.00
S150.000.00
Sl.000,000.00
S8.494.000.00
SI. 698.800.00
S10. 192.800.00
54
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Table 10
Alternative 3: Annual Operations and Maintenance Costs
ACTIVITY
Mowing
Reseeding
Settlement and Subsidence Control
Surveys
Fill Material
Access Roads
Fence Maintenance
Leachate Collection and Treatment
Cover Maintenance
Miscellaneous
SUBTOTAL Annual Maintenance Cost
Contingency (20%)
TOTAL Annual Maintenance Cost
Net Present Worth (30 years, 7% interest rate, P/A = 12.4)
ESTIMATED
COST
$1.500.00
S3.UOO.OO
$8.00000
$10.000.00
S8.000.00
$7.000.00
$40.000.00
S2.500.00
SI 0.000.00
S90.000.00
$18.000.00
$108.000.00
$1.339.200.00
Alternative 3: TOTAL ESTIMATED COSTS = Capital costs (Table 9) + O&M costs (Table 10)
Alternative 3: TOTAL ESTIMATED COSTS - $10,192,800 + $1,339,200 = Sll.S32.Ott
55
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INTERIM ACTION
RECORD OF DECISION
Hewitt Date
Lieutenant Colonel, 00
Commander, Iowa AAP
Menig Date
Deputy Assistant Chief of Staff
for Installation Management
U.S. Army
Dennis Grams, P.E. Date
Regional Administrator
U.S. Environmental Protection Agency
Region 1
56
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