PB96-964021
EPA/ROD/R04-96/278
April 1997
EPA Superfimd
Record of Decision:
Memphis Defense Depot (DLA),
aka: Defense Depot, Operable Unit 1,
Memphis, TN
5/1/1996
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Record of Decision for Interim Remedial Action
of the Groundwater at Dunn Field (OU-1) at the
Defense Distribution Depot Memphis, Tennessee
January 1996
Prepared for
U.S. Army Corps of Engineers
Huntsville Division
Prepared by
CH2M HILL, Inc.
Montgomery, AL
DACA87-94-D-0009
110491.IR
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Record of Decision for Interim Remedial Action
of the Groundwater at Dunn Field (OU-1) at the
Defense Distribution Depot Memphis, Tennessee
January 1996
Prepared for
U.S. Army Corps of Engineers
Huntsville Division
Prepared by
CH2M HILL, Inc.
Montgomery, AL
DACA87-94-D-0009
110491.IR
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Contents
«
Section Page
Acronyms iv
Executive Summary v
Part 1—Declaration for the Record of Decision Interim Remedial Action
of the Groundwater at Dunn Field (OU-1)
1.1 Site Name and Location 1-1
1.2 Statement of Basis and Purpose 1-1
1.3 Assessment of the Site 1-1
1.4 Description of Interim Remedial Action '. 1-1
1.5 'Declaration 1-2
Part 2—Decision Summary
2.1 Site Location and Description 2-1
2.2 Site History and Enforcement Activities 2-1
2.3 Highlights of Community Participation 2-5
2.4 Scope and Role of Operable Units 2-6
2.5 Summary of Site Characteristics 2-7
2.6 Summary of Site Risks 2-9
2.7 Description of Alternatives 2-11
2.8 Summary of the Comparative Analysis of Alternatives 2-18
2.9 . Summary of Selected Remedy 2-20
2.10 Statutory Determinations • 2-22
•** •* * T~* /* - _.-___ ' ^% <•> f\
z.n iv.ciciciu;cs , 2. 50
Part 3—Responsiveness Summary 3-1
mgm95-DDMTMisc./002.WP5
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Tables
Number Page
1 Comparison of Constituents to Standards in Dunn Field Groundwater 2-10
2 Alternatives for Interim Remediation 2-13
3 Obervational Methods for Dunn Field Groundwater Remediation 2-22
4 Preliminary Identification of Potential Chemical-Specific ARARs
for DDMT 2-24
5 Preliminary Identification of Potential Location-Specific ARARs
at DDMT 2-25
6 Preliminary Identification of Potential Action-Specific ARARs
for DDMT 2-26
7 ' Maximum Effluent Standards for Discharge of Waste into the Municipal
Sewerage System 2-28
Figures
1 DDMT Location in Memphis Metropolitan Area 2-2
2 Operable Unit Locations 2-3
3 Generalized Conceptual Site Model (Cross Section View) .2-12
4 Proposed Groundwater Recovery System (OU-1) 2-17
mgm95-DDMTMisc./002.WP5 111
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Acronyms
AEHA U.S. Army Environmental Hygiene Agency
AOC Area of Concern
AR Administrative Record
ARAR Applicable or relevant and appropriate requirement
BRA Baseline risk assessment
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
CRP Community Relations Plan
DDMT Defense Depot Memphis, Tennessee
DLA Defense Logistics Agency
DNAPL Dense non-aqueous phase liquid
DOD Department of Defense
EE/CA Engineering evaluation/cost analysis
EPA U.S. Environmental Protection Agency
gpm Gallons per minute
IRA Interim remedial action
MCL Maximum contaminant level
MCLG Maximum contaminant level goal
mgd Million gallons per day
NCP National Oil and Hazardous Pollution Contingency Plan
NGVD National Geodetic Vertical Datum
NPDES National Pollutant Discharge Elimination System
NPL National Priorities List
O&M Operations and maintenance
OU Operable unit
PCB Polychlorinated biphenyl
PCP Pentachlorophenol
POTW Publicly owned treatment works
PW Present worth
RAB Restoration Advisory Board
RCRA Resource Conservation and Recovery Act
RFA RCRA Facility Assessment
RI/FS Remedial investigation/feasibility study
ROD Record of Decision
SARA Superfund Amendments and Reauthorization Act
SWMU Solid waste management unit
TDEC Tennessee Department of Environment and Conservation
USATHMA U.S. Army Toxic and Hazardous Materials Agency
UV Ultraviolet
VOC Volatile organic compound
mgm95-DDMT Misc./002.WP5
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Executive Summary
This Record of Decision (ROD) presents the selected interim remedial action (IRA) for
DDMT in accordance with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA). In 1992, after receiving a Hazard Ranking System
(MRS) score of 58.06, DDMT was placed on the National Priorities List by the
Environmental Protection Agency. The selected IRA provides for hydraulic control of a
contaminant plume in groundwater beneath Dunn Field. Contaminants identified as those
of potential concern include volatile organic compounds, such as solvents used for
cleaning mechanical parts, and metals. It is not intended as a permanent solution;
however, it is intended to be compatible with the final remedy.
DDMT and the involved regulatory agencies have been working to inform the community
about activities involved with the site since 1992 through press releases, mailings,
newspaper ads, and public meetings.
•Eight alternatives, each consisting of groundwater extraction, groundwater treatment, and
disposal components, were evaluated. The alternative chosen as the preferred alternative
consists of extraction on/offsite and discharge to a publicly owned treatment works
(POTW). This alternative assumes that pretreatment will not be necessary before
treatment at the POTW. If, however, chemical analyses indicate that pretreatment is
necessary, a pretreatment provision is part of the contingency remedy.
mgm95-DDMT Misc./002.WP5
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Parti
Declaration for the Record of Decision
Interim Remedial Action of the Groundwater
at Dunn Field [Operable Unit (OU-1)]
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
? REGION IV
345 COURTLAND STREET. N.E.
ATLANTA. GEORGIA 3O365
May 1, 1996
4WD-FFB
Certified Mail
Return Receipt Requested
Colonel Michael J. Kennedy, Commander
Defense Distribution Depot Memphis
2163 Airways Boulevard
Memphis, Tennessee 38114-5210
SUBJ: Concurrence with Interim Record of Decision, Operable Unit 1
Defense Distribution Depot Memphis, Tennessee
Dear Col. Kennedy:
The U.S. Environmental Protection Agency (EPA) Region IV has reviewed the above
referenced decision document and concurs with the Interim Record of Decision (EROD) for
groundwater at Operable Unit 1, Dunn Field, as supported by the Remedial Investigation in
progress.
The selected remedy is Alternative 8 in the IROD. EPA concurs with the selected remedy as
detailed in the IROD with the following stipulation: It is unuersiuud that the selected ir.icrin:
remedy for Operable Unit 1 may not be the final remedial action to address all media potentially
affected by past disposal practices at this unit.
This action is protective of human health and the environment, complies with Federal and
State requirements that are legally applicable or relevant and appropriate to the remedial action
and is cost effective.
Sincerely,
Richard D. Green
Acting Director
Waste Management Division
cc: Jordan English, Tennessee Department of Environment & Conservation
' ,->;: /?,Ti-/v/<-,; P.:;
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1.1 Site Name and Location
Defense Depot Memphis, Tennessee (DDMT)
Memphis, Shelby County, Tennessee
1.2 Statement of Basis and Purpose
This decision document (Record of Decision [ROD]) presents the selected interim remedial action
(IRA) for the DDMT site, Memphis, Tennessee, developed in accordance with the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA),
as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA), 42 U.S.C.
Section 9601 et seq., and to the extent practicable, the National Oil and Hazardous Pollution
Contingency Plan (NCP) 40 Code of Federal Regulations (CFR) Part 300.The DDMT is the lead
agency for the remedial investigation/feasibility study (RI/FS) process for the site. The U.S.
Environmental Protection Agency (EPA) and the Tennessee Department of Environment and
Conservation (TDEC) are the supporting regulatory agencies for the site. In accordance with 40
CFR 300.430, the regulatory agencies have provided input during this process. The regulatory
agencies are provided with a draft IRA ROD for review and their comments are incorporated into
the final document. The U.S. EPA and the State of Tennessee concur with the selected interim
remedy.
1.3 Assessment of the Site
Actual or threatened releases of hazardous substances from the DDMT site, if not addressed by
endangerment to public health, welfare, and the environment.
1.4 Description of Interim Remedial Action
This ERA provides for hydraulic control of a contaminant plume in groundwater beneath Dunn
Field (also called OU-1). Because the contaminated Fluvial Aquifer poses a potential threat to the
deeper Memphis Sand Aquifer, it is considered as a potential threat to human health and the
environment. Thus, the groundwater IRA is designed to provide a quick, interim response
measure that will help prevent the possible contamination of the area's drinking water supply. As
a contingency remedy, the ERA also includes a provision for pretreatment if necessary. As
described in the IRA Proposed Plan contained in the Administrative Record, follow-on activities
include monitoring the groundwater plume and its response to the IRA. Once the plume has been
fully characterized, subsequent action may be taken to provide long-term definitive protection,
including remediation of source areas. To the extent possible, the interim action will not be
inconsistent with, nor preclude implementation of, the expected final remedy. RI/FS activities at
OU-2, OU-3, and OU-4 will address contamination found within the southwestern quadrant,
southeastern watershed and golf course, and northern portions of the Main Installation,
respectively.
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including remediation of source areas. To the extent possible, the interim action will not
be inconsistent with, nor preclude implementation of, the expected final remedy. RI/FS
activities at OU-2, OU-3, and OU-4 will address contamination found within the
southwestern quadrant, southeastern watershed and golf course, and northern portions of
the Main Installation, respectively. This IRA addresses only Dunn Field. OU-2, OU-3,
and OU-4 will be addressed in the remedial documents for those OUs.
The major components of the selected IRA for OU-1 include the following:
• Evaluation of aquifer characteristics which may include installation of a
pump test well
• Installation of additional monitoring wells to locate the western edge of the
groundwater plume
• Installation of recovery wells along the leading edge of the plume
• Obtaining discharge permit for disposal of recovered groundwater to the
T. E. Maxson Wastewater Treatment Plant publicly owned treatment works
(POTW) or municipal sewer system
• Operation of the system of recovery wells until the risk associated with the
contaminants is reduced to acceptable levels or until the final remedy is in
place
• Chemical analysis will be conducted to monitor the quality of the discharge
in accordance with the city discharge permit requirements; the permit will
include parameters to be monitored and frequency.
1.5 Declaration
This interim action is protective of human health and the environment, complies with
federal and state requirements that are legally applicable or relevant and appropriate, and
is cost-effective. This action is interim; it is not intended as a permanent or final
remedy. However, it is intended to be compatible with the permanent solution. It is not
intended to be the permanent solution, and uses alternative treatment technologies to the
maximum extent practical for this interim response. Because this action does not
constitute the final remedy for this OU, the statutory preference for remedies that employ
treatment that reduces toxicity, mobility, or volumes as a principal element has not been
entirely accommodated and will be addressed at the time of the final response action.
Subsequent actions are planned to address fully the threats posed by the conditions at this
OU. Because this remedy will result in hazardous substances remaining onsite above
health-based levels, a review will be conducted to ensure that the remedy continues to
provide adequate protection of human health and the environment within 5 years after the
mgm95-DDMTMisc./001.WP5 1-2
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This IRA addresses only Dunn Field. OU-2, OU-3, and OU-4 will be addressed in the remedial
documents for those OUs.
The major components of the selected IRA for OU-1 include the following:
• Evaluation of aquifer characteristics which may include installation of a pump
test well
• Installation of additional monitoring wells to locate the western edge of the
groundwater plume
• Installation of recovery wells along the leading edge of the plume
• Obtaining discharge permit for disposal of recovered groundwater to the T. E.
Maxson Wastewater Treatment Plant publicly owned treatment works (POTW) or
municipal sewer system
• Operation of the system of recovery wells until the risk associated with the
contaminants is reduced to acceptable levels or until the final remedy is in place
• Chemical analysis will be conducted to monitor the quality of the discharge in
accordance with the city discharge permit requirements; the permit will include
parameters to be monitored and frequency.
1.5 Declaration
This interim action is protective of human health and the environment, complies with federal and
state requirements that are legally applicable or relevant and appropriate, and is cost-effective.
This action is interim; it is not intended as a permanent or final remedy. However, it is intended
to be compatible with the permanent solution. It is not intended to be the permanent solution, and
uses alternative treatment technologies to the maximum extent practical for this interim response.
Because this action does not constitute the final remedy for this OU, the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or volumes as a principal element
has not been entirely accommodated and will be addressed at the time of the final response action.
Subsequent actions are planned to address fully the threats posed by the conditions at this OU.
Because this remedy will result in hazardous substances remaining onsite above health-based
levels, a review will be conducted to ensure that the remedy continues to provide adequate
protection of human health and the environment within 5 years after the commencement of this
remedial action. Because this is an interim action ROD, review of the remedy will be ongoing as
DDMT continues to develop the final remedial action for OU-1.
CHRISTINE E. KARTMAN Date
Chief, Environmental Protection and Safety Office
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THU i:t)»
STATE OF TENNESSEE
OEPARTMENI OF ENVIRONMENT AND CONSERVATION
MEMPHIS ENVIRONMENTAL FIEL.D OFFICE
SUITE E-045. PERIMETER PARK
2510MT.MORIAH
MEMPHIS. TENNERRPP MI 15-1520
April 24, 1996
Commander
Defense Distribution Depot Memphis
Attn: DDMT-DE (Ms. Christine Kartman)
2163 Airways Blvd.,
Memphis, Tennessee 38114-5210
Re: Concurrence for the Record of Decision for Interim Remedial Action of the GrounHwater
at Dunn Field (OU-1) at the Defense Depot site, Memphis, Shelby County, Tennessee,
April 1996, TDSF #79-736, cc 82
Dear Ms. Kartman:
The Tennessee Division of Superfund (TDSF) Memphis Field Office (MFO) has reviewed the ,,
Interim Remedial Action Record of Decision for the Groundwater at Dunn Field, for the Defense
Depot site dated April IPP6 referenced above.
The Tennessee Department of Enviiutimcni and Conservation (TDEC) is in concurrence with the
selected remedy, a pump and treat containment alternative, Alternative 8 as described. TDEC has
been actively involved with the development of the alternatives as well as the selection process
through closely coordinated project management among Base Closure Team (BCT) members and
extended BCT members.
This concurrence is provided within the authority of the Federal Facilities Agreement (FFA) for the
Defense Depot, the Defense Department/State Memorandum yf Agreement (DSMOA), and the
delegated powers of the Commissioner of TDEC as part of the President's five step Base Cleanup
Plan (BCP) process.
Sincerely,
Wilier, Director
Tennessee Division of SupeiTuud
c: TDSF, NCO
TDSF, MFO
Dann Spariosu
United States .Environmental Protection Agency
Federal Facilities Branch
3'I5 Courtland Street, N.C.
Atlanta, GA 30365
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Part 2
Decision Summary
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2.1 Site Location and Description
DDMT covers 642 acres of federal land in Memphis, Shelby County, Tennessee, in the
extreme southwestern portion of the state. Approximately 5 miles east of the Mississippi
River and just northeast of the Interstate 240-Interstate 55 junction, DDMT is in the
south-central section of Memphis, approximately 4 miles southeast of the Central
Business District and 1 mile northwest of Memphis International Airport. Airways
Boulevard borders DDMT on the east and provides primary access to the installation.
Dunn Avenue, Ball Road, and Perry Road serve as the northern, southern, and western
boundaries, respectively. The installation is surrounded by mixed residential,
commercial, and industrial areas. Figure 1 shows the installation's location within the
Memphis area.
The Defense Logistics Agency (DLA), an agency of the Department of Defense (DOD),
provides logistics support to military services. As a major field installation of the DLA,
DDMT receives, warehouses, and distributes supplies common to all U.S. military
services and some civil agencies located primarily in the southeastern United States,
Puerto Rico, and Panama. Stocked items include food, clothing, electronic equipment,
petroleum products, construction materials, and industrial, medical, and general supplies.
The installation contains approximately 110 buildings, 26 miles of railroad track, and 28
miles of paved streets. It has about 5.5 million square feet of covered storage space and
approximately 6.0 million square feet of open storage space. The land and buildings are
owned by the U.S. Army and leased by DLA. DDMT consists of two main sections:
the Main Installation, which is intensely developed, and Dunn Field, an open storage area
about 64 acres in size. A more detailed description of the OUs, whose current
boundaries are shown in Figure 2, is found in Section 2.4.
2.2 Site History and Enforcement Activities
DDMT began operations in 1942 with the charge to inventory and supply materials for
the U.S. Army. In 1964, its mission was expanded to serve as one of the principal
distribution centers for a complete range of commodities.
Past activities at DDMT include a wide range of storage, distribution, and maintenance
practices. Dunn Field (OU-1) has been used as a landfill area (northwestern quadrant), a
storage area for mineral stockpiles (southwestern and southeastern areas), and a pistol
range, and later as a pesticide storage area (northeastern area). Activities in the
southwestern quadrant of the Main Installation (OU-2) have included hazardous material
storage and recoupment (Building 873), sandblasting and painting activities (Buildings
1086 through 1089), and maintenance (Building 770). The southeastern portion of the
Main Installation (OU-3) includes the bulk of the storage and distribution warehouses at
DDMT. Other activities that are documented to have occurred in this area include the
polychlorinated biphenyl (PCB) transformer storage (near Building 274), pesticide and
mgm95-DDMTMisc./001.WP5 2-1
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SCALE IN MILES
LEGEND
INTERSTATE
STATE LINE
RIVER CREEK
ALLEN
DDMT
AREA OF
MEMPHIS,
TENNESSEE
MEMPHIS LIGHT, GAS AND
WATER DIVISION WELL FIELD
Source: En(i«^ring-Science, 1993
FIGURE 1
DDMT LOCATION IN MEMPHIS METROPOLITAN AREA
Defense Depot Memphis, Tenness^l
mwp-0022.ogn
'09-MAY-1995
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1000 500
1000
OU-1
DUNN FIELD
LEGEND
DDMT BOUNDARY
OU BOUNDARY
Source: Engineering-Science. 1993
BALL ROAD
FIGURE 2
OPERABLE UNIT LOCATIONS
Defense Depot Memphis, Tennessee
mwp-0023.dgn 09-MAY-1995
2-3
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herbicide storage and use (several locations), and fire truck pump testing (Lake
Danielson). The northern portion of the installation (OU-4) has a history of the following
major activities: hazardous material storage (several locations), treatment of wood
products with pentachlorophenol (PCP) (Building 737), and storage of items awaiting
disposal (several locations).
Until 1970, army supplies, including hazardous and nonhazardous materials whose
containers were damaged or shelf life expired, were occasionally burned or buried in a
portion of Dunn Field. Wastes disposed of in this manner may have included oil and
grease, paint, paint thinner, methyl bromide, pesticides, herbicides, and food supplies.
Documentation indicates that most of the materials disposed of during this time period
were buried in the northwestern portion of Dunn Field.
In 1981, the U.S. Army Toxic and Hazardous Materials Agency (USATHMA) prepared
an installation assessment of hazardous materials disposal practices to assess potential
sources of contamination. The burial sites at Dunn Field were identified and ranked as
having the greatest potential for offsite migration of contaminants in groundwater.
In 1982, a hydrogeologic evaluation was conducted by the U.S. Army Environmental
Hygiene Agency (AEHA) to determine groundwater quality beneath Dunn Field. Seven
wells were installed in the northwestern quadrant of Dunn Field and analyzed for
inorganic constituents. The results did not reflect any significant groundwater
contamination from the past disposal operations.
A Resource Conservation and Recovery Act (RCRA) Facility Assessment (RFA) was
performed in 1989 by A. T. Kearney to.identify solid waste management units (SWMUs)
and areas of concern (AOCs). To satisfy CERCLA requirements, an RI/FS was
conducted in 1989 and concluded in 1990. The RI was conducted on a sitewide basis to
confirm the presence or absence of contamination, to evaluate the extent and significance
of detected contamination, and to provide a scientific foundation for cleanup alternatives.
An RI Report was submitted to EPA in August 1990. A quantitative baseline risk
assessment (BRA) was conducted as part of the RI and submitted along with the RI
Report. The remedial alternatives are presented in a draft FS, which was submitted to
EPA in September 1990. A final RI for the installation has not yet been accepted by
either EPA or TDEC.
During the RI, monitoring wells were installed in the Fluvial Aquifer and Memphis Sand
Aquifer. Several groundwater samples collected from monitoring wells around the
installation contained levels above regulatory limits of volatile organic compounds
(VOCs) and heavy metals. The results suggested that the groundwater contaminant plume
was generally migrating to the west and northwest of Dunn Field. Later data (ESE 1994)
indicates that there may be a west to southwest component. In 1992, the EPA placed
DDMT on the National Priorities List (NPL).
mgm95-DDMTMisc./001.WP5 2-4
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In 1993, an Engineering Report-Removal Action for Groundwater (Engineering Science),
was prepared for DDMT. The intent of the report was to meet all requirements of the
engineering evaluation/cost analysis (EE/CA) under CERCLA and the NCP for a
non-time critical removal. The report evaluated a variety of technologies, previously
presented in the 1990 RI/FS, that would treat contaminated groundwater in the Fluvial
Aquifer to prevent possible human exposure.
This IRA represents the first step in the remediation of the contaminated groundwater
beneath the northern portion of Dunn Field (OU-1). Additional actions will be necessary
to provide long-term definitive protection for OU-1.
2.3 Highlights of Community Participation
DDMT, EPA, and TDEC have made significant efforts to inform interested parties and
provide input on activities associated with the site. As part of its requirements under
CERCLA, DDMT has been working with the community surrounding the site since 1992.
In October 1992, press releases informing the community of the NPL listing of the site
were released. The Information Repository located at the Memphis/Shelby County Public
Library, 1850 Peabody Avenue, Memphis, Tennessee, was established in May 1993.
Two other repositories are located at the Cherokee Branch Public Library and the
Memphis-Shelby County Public Health Department. A draft final Community Relations
Plan (CRP) was issued in April 1994 and has been placed in the information repositories.
On May 24, 1993, at the request of the Memphis Mayor's office, DDMT had a meeting
at Corey Junior High School to discuss the restoration effort and to provide a forum for
the community to express its concerns about health issues. DDMT also led a public
exhibition and discussion on the restoration process ou August 10, 1993. In December
1994, DDMT, EPA, and TDEC held a public meeting to discuss the start of the RI/FS.
The FS, the Proposed Plan, and the Administrative Record (AR) for the OU-1 IRA were
released to the public in November 1994. These documents were made available in the
AR and maintained in the repositories and in the information repository at the site. The
notice of availability of these documents and the AR was published in December 1994 in
the Silver Star News, the Tri-State Defender, and the Commercial Appeal. A public
comment period was held from December 4, 1994, to January 17, 1995. In addition, a
public meeting was held on December 20, 1994. At this meeting, representatives from
DDMT, EPA, and TDEC answered questions about problems at the site and the remedial
alternatives under consideration, including the IRA. Responses to the comments received
during this comment period are presented in the responsiveness summary in Part 3 of this
document.
The Technical Review Committee, established in February 1994, was converted to a
Restoration Advisory Board (RAB) in July 1994. The RAB consists of representatives
from the Memphis area community and from the state and federal government, and meets
on a monthly basis to discuss activities associated with DDMT. After each meeting,
meeting minutes are distributed to board members.
mgm95-DDMT Misc./OOl .WP5 2-5
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In addition to the RAB, newsletters are prepared on a quarterly basis and disseminated to
approximately 3,000 individuals. The mailing list of 3,000 was established from the
response to an initial mailing to 20,000 individuals within a 1-mile radius of DDMT in
October 1994, the response to newspaper advertisements, and from the existing DDMT
mailing list. Factsheets are also completed and distributed whenever new or additional
restoration activities occur at DDMT. A hotline (901-775-4569) was established in
February 1994 to assist local citizens or other interested parties in obtaining information
concerning the environmental restoration activities at the site.
2.4 Scope and Role of Operable Units
Because of the size of the installation (642 acres) and its complexity, DDMT, EPA and
TDEC have organized the work at this site into the four OUs, which are discreet parts of
an entire response action. Figure 2 shows the location and areal extent of the OUs.
Dunn Field, which is the only area on DDMT where burial of waste is known to have
occurred, is designated OU-1. Substances found in OU-1 probably resulted from use of
the area for landfill operations, mineral stockpiles, pistol range use, and pesticides
storage.
The Main Installation is divided into three other OUs. OU-2, in the southwestern
quadrant, is an area where maintenance and repair activities have occurred. Potential
contamination of OU-2 may have resulted from spills or releases from the hazardous
material storage and repouring area, or sandblasting and painting activities. OU-3
includes the Golf Course Pond, Lake Danielson, and former transformer and pesticide
storage areas. Storage of PCBs and the use of pesticides and herbicides are potential
sources of contamination for OU-3. OU-4, in the north-central area, is mainly
characterized by the presence of the main hazardous materials storage building at DDMT.
Principal contamination in OU-4 probably resulted from a wood treatment operation and
hazardous material storage.
Because the contaminated groundwater beneath Dunn Field poses a potential threat to the
drinking water aquifer, it is considered a possible threat to human health and the
environment. Thus, the objective of the groundwater IRA is to provide a quick response
measure that will help prevent the possible contamination of the area's drinking water
supply. Follow-on activities include characterizing and monitoring the groundwater
plume migration. Once the plume has been characterized, subsequent action may be
taken to provide long-term definitive protection, including remediation of source areas.
To the extent practicable, the interim action will be consistent with any planned future
actions.
mgm95-DDMTMisc./001.WP5 2-6
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The IRA addresses contamination of groundwater beneath Dunn Field from past disposal
practices at DDMT. The IRA represents the first step in the remediation of the
contaminated groundwater beneath the northern portion of Dunn Field. The remainder of
OU-1 and OUs-2, 3, and 4 will be evaluated later and will be addressed in future
documents.
2.5 Summary of Site Characteristics
The major site characteristics presented in the RI/FS that are applicable to OU-1 are
summarized below.
2.5.1 Physiography
DDMT is situated within the Gulf Coastal Plan subdivision of the Atlantic Coastal Plain
Physiographic Province. The area is characterized by dissected loess-covered uplands
and generally lacks distinct features.
Dunn Field lies just north of the Main Installation and Dunn Avenue, and consists of
approximately 64 acres of undeveloped land. Most of Dunn Field is unpaved. About
one-half of the area is grassed; the remaining area contains crushed rock and bauxite and
fluorspar piles. Several large hardwood trees are present in the northeastern part of the
field. The southwestern quadrant of the field is a grassed, gently sloping area. The
southeastern quadrant is a level zone used for both covered and uncovered bulk materials
storage (bauxite and fluorspar).
Dunn hiekfs topography is a levei-to-gentiy roiling terrain which has been somewhat
altered by past activities of heavy equipment operators. The land appears to slope to the
west from the bauxite piles in the center of the field. An arc-shaped ridgeline separates
the field's two northern quadrants. In the northeastern quadrant of the field, the areas
surrounding the former pistol range (later used as a pesticide/herbicide storage shed
[Building 1184]) and the former burn area are level and grassed. The northwestern
quadrant of the field (the portion used for burial of waste materials) is a level-to-gently
sloping grassed area. Surface elevations range from a low of 273 ft, National Geodetic
Vertical Datum of 1929 (NGVD), at the north outfall/installation boundary fenceline to
315 ft NGVD in the field's approximate center. Maximum local relief is about 25 ft at
the pistol range bullet stop.
Installation surface drainage is accomplished by overland flow to swales, ditches,
concrete-lined channels, and an efficient storm drainage system. Most of DDMT is
generally level with, or above, surrounding terrain; therefore, DDMT receives little or no
runoff from adjacent areas. Most Dunn Field drainage is achieved by overland flow to
the adjacent properties to the north and west. The northeastern quadrant drains east to a
concrete-lined channel, or to adjacent properties to the north. The concrete-lined channel
consists of two separate segments that join approximately 200 ft north of Building 1184.
mgm95-DDMTMisc./001.WP5 2-7
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Both channel segments convey adjacent residential neighborhood storm water through the
northeastern quadrant of Dunn Field. The concrete-lined channel directs flow northward
to Cane Creek, which drains into Nonconnah Creek at a point several miles southwest of
DDMT. Nonconnah Creek drains into Lake McKellar, a Mississippi River tributary.
Runoff from the northwestern quadrant flows overland to a roadside ditch along Kyle
Street (northwestern boundary of the installation). The remainder of the runoff flows
overland to the west onto neighboring properties outside of DDMT.
2.5.2 Hydrogeology
The Dunn Field area of DDMT is covered by a loess deposit, which is a semi-cohesive
windblown deposit of silt, silty sand, and silty clay. The loess is about 20 ft thick in the
vicinity of Dunn Field and may occasionally reach 30 ft in thickness. Although the loess
is not typically a-water-bearing zone, seasonal perched groundwater may occur. The
extent of this potential perched zone is unknown. There is no evidence that the loess
produces water to wells in the DDMT vicinity. The loess is underlain by the Fluvial
Deposits, the Jackson Formation/Upper Claiborne Group, and the Memphis Sand.
The Fluvial Deposits consist of a top layer of silty clay, silty sand, or clayey sand; a
clean, fine to medium-grained sand; and a basal gravelly sand. The thickness of the
Fluvial Deposits hi Dunn Field ranges from 50 to 70 ft. This unit forms the shallow
aquifer hi the vicinity of Dunn Field and receives recharge from rainfall infiltration and
lateral groundwater inflow. Discharge is toward the Mississippi River to the west and
possibly by leakage into the underlying Memphis Sand Aquifer through the Jackson
Formation/Upper Claiborne confining bed. Data collected from the site suggests that
groundwater hi the Fluvial Aquifer is moving generally toward the west in the Dunn
Field area.
Below the Fluvial Deposits is the Jackson Formation and Upper Claiborne Group
consisting of stiff gray or orange plastic, lean to fat lignitic clay, silt, and fine sand with
minor lenses of lignite. This stratigraphic unit reaches thicknesses of approximately 80 ft
and forms a regional confining bed separating the Fluvial Deposits and the underlying
Memphis Sand Aquifer. Although no areas of hydraulic connection have been confirmed
in the vicinity of DDMT to date, investigations are underway to verify the existence of a
potential interconnection.
At Dunn Field, the top of the Memphis Sand Aquifer is about 160 ft below ground level
along the western property line and approximately 140 ft below ground level along the
eastern property line. The formation is composed of thin-bedded, white to brown or
gray, very fine grained to gravelly, partially argillaceous and micaceous sand. The
aquifer ranges in thickness from 500 to about 900 ft and is under confined conditions.
mgm95-DDMTMisc./001.WP5 2-8
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The Memphis Light, Gas, and Water Division operates eight well fields that extract water
from the Memphis Sand for municipal supply. The Allen Well Field is located 1 to 2
miles west of DDMT. A potentiometric surface map, (Park 1990, plate 3) indicates that
groundwater flow in the Memphis Sand Aquifer beneath DDMT is toward the West.
2.5.3 Groundwater Contamination
Chemicals of potential concern identified hi Dunn Field monitoring wells screened in the
Fluvial Aquifer include the following:
Volatile Organic Compounds
Carbon tetrachloride 1,1 -Dichloroethylene
1,2-Dichloroethylene Tetrachloroethylene
1,1,2,2-Tetrachloroethane Trichloroethylene
Metals
Arsenic 'Barium
Chromium Lead
Nickel
The highest concentration of constituents detected in the groundwater samples collected
from the Fluvial Aquifer wells are presented hi Table 1. To date, constituents of concern
in the Fluvial Aquifer have not been detected in Memphis Sand Aquifer groundwater
samples in the vicinity of the site.
The constituents of concern found hi the Fluvial Aquifer beneath Dunn Field occur at
concentrations above the established maximum coiiiaiiiiiiain levels (MCLs) and maximum
contaminant level goals (MCLGs). A comparison of MCLs and MCLGs with the data
from the RI is presented hi Table 1.
Over the course of 3 sampling efforts conducted at Dunn Field (1989, 1990, and 1992),
volatile organics were detected above MCLs hi 22 out of 35 Fluvial Aquifer groundwater
samples. Metals concentrations above MCLs were detected in 25 out of 35 groundwater
samples collected during this tune period.
2.6 Summary of Site Risks
In 1990, as part of the RI/FS, a preliminary risk assessment was performed hi accordance
with EPA guidance available at that tune. Potential exposure points for contaminated
groundwater from Dunn Field were identified as the following:
• Ingestion of groundwater through the public water supply
• Contact with potable water during bathing
• Inhalation of vapors from VOCs in potable water during household use
mgm95-DDMT Misc./OOl .WP5 2-9
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Table 1
Comparison of Constituents to Standards
in Dunn Field Groundwater
to
I—*
o
Constituent
Volatile Organic Compounds
1 , 1-Dichloroethene
1,2-Dichloroethene (total)
Tetrachloroethene
Trichloroethene
Carbon tetrachloride
Metals
Arsenic
Barium
Chromium
Lead
Nickel
MCL
fog/L)
7
70
5
5
5
50
2,0001
50
152
100
RI Phase I
Highest Levels 1989
(ftg/L)
130 (MW-10)
5203 (MW-11)
210 (MW-5)
1,7003(MW-12)
77 (MW-6)
85 (MW-10)
3,7404 (MW-14)
1,2404 (MW-7)
6534 (MW-10)
6024 (MW-7)
RI Phase n
Highest Levels 1990
(Mg/L)
160 (MW-10)
5103 (MW-12)
2403 (MW-10)
5.1003 (MW-12)
40 (MW-6)
210 (MW-14)
1,900 (MW-10
340 (MW-7)
1,000 (MW-10)
170 (MW-7 & 10)
Source: Environmental Science, Inc., 1993.
Notes:
'Maximum contaminant level goals (MCLGs)
2Action level
Identified in the analysis from a secondary dilution factor
4Spiked sample recovery not within control limits
Abbreviations:
Hg/L = Micrograms per liter
MW = Monitoring well
mgm95-DDMT-Misc./003.WP5
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The transport medium and exposure pathway for the exposure scenarios identified above
all relate to groundwater. Contaminants can potentially leach from materials associated
with past disposal activities at Dunn Field. Several of these contaminants are already
present in the Fluvial Aquifer as a result of dispersion and infiltration. The Fluvial
Aquifer, which is not used as a potable water supply, potentially recharges the Memphis
Sand Aquifer by leakage. This potential leakage could provide a pathway for
contaminants to the deeper Memphis Sand Aquifer, the drinking water aquifer for the
City of Memphis. A conceptual site model is shown in Figure 3.
The Allen Well Field, located approximately 1 mile south of Dunn Field, is one of eight
pumping centers serving the Memphis area. With 35 wells, the Allen Well Field pumps
roughly 21 million gallons a day (mgd) of potable water from the Memphis Sand Aquifer
and accounts for approximately 15 percent of the water used within the Memphis area.
Contamination of the Memphis Sand Aquifer caused by leakage from the contaminated
Fluvial Aquifer could occur, thus directly affecting the Memphis water supply source.
Results of the preliminary risk assessment indicate that there is a potential public health
risk associated with the Fluvial Aquifer groundwater. Actual or threatened releases of
hazardous constituents from Dunn Field, if not addressed by the preferred IRA, may
present a current or potential threat to public health, welfare, or the environment.
The principal goals of this groundwater IRA are to incrementally remove contaminants
from the Fluvial Aquifer, to decrease risk by mitigating the spread of constituents toward
the Allen Well Field, and to create a hydraulic barrier to prevent contamination in the
Fluvial Aquifer at Dunn Field from reaching the Allen Well Field.
Although the IRA is not anticipated to achieve compliance with MCLs, it is consistent
with the objective to protect the Memphis Sand Aquifer. Long-term operation of a
groundwater removal system will help to achieve MCLs by incrementally removing
contaminants.
The more specific findings of the BRA will be included in the final action ROD for
OU-1, along with the ultimate cleanup objectives. No changes were made to the
preferred alternative as presented in the Proposed Plan.
2.7 Description of Alternatives
Eight alternatives were evaluated for addressing the groundwater contamination beneath
Dunn Field. These alternatives are listed in Table 2. Each of the alternatives consist of
three elements—groundwater extraction, groundwater treatment, and disposal. Extraction
option alternatives range from no action to installation of deep wells on- and off site.
Treatment possibilities range from none to air stripping or ultraviolet (UV)/oxidation of
metals. Groundwater disposal options range from none to discharge to surface drainage,
discharge to the municipal sewer system, or reinjection into onsite wells. These
alternatives are described in greater detail in the following paragraphs. Cost analyses
provided are based on 1990 dollars and may represent a substantial cost increase by the
time implementation begins.
mgm95-DDMTMisc./001.WP5 2-11
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GENERALIZED SITE MODEL
WELL FIELD
PUBLIC
DRINKING
WATER
LAND
SURFACE
SURFACE
DEPOSITS
SURFACE RUNOFF
LOESS (SILT. SILTY CLAY,
SILTY SAND) LEACHING
FLUVIAL DEPOSITS (FINE TO MEDIUM SANDS,
WITH MINOR LENSES OF CLAY AND GRAVEL)
FLUVIAL AQUIFER
JACKSON-CLAIBORNE CLAY
POSSIBLE LEAKAGE?
SAND
AQUIFER
NOT TO SCALE. VERTICAL SCALE EXAGGERATED
Source: CEHND. 1994
FIGURE 3
GENERALIZED CONCEPTUAL SITE MODEL (CROSS SECTION VIEW)
Defense Depot Memphis, Tennessee
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Table 2
Alternatives for Interim Remediation
Alternative
1
2
Extraction
No Action
Wells onsite
Treatment
None
Air stripping with
Disposal
None
Municipal sewer
Wells on- and offsite
Wells onsite
Wells onsite
Wells onsite
Wells onsite
metals removal if
necessary
Air stripping with
metals removal if
necessary
Air stripping with
metals removal if
necessary
Air stripping with
metals removal if
necessary
Air stripping with
metals removal if
necessary
Air stripping with
metals removal if
necessary
Municipal sewer
Municipal sewer
Surface drainage
Surface drainage
Reinjection upgradient
onsite
(preferred)
Alternative 8 is the preferred alternative.
2.7.1 Alternative 1: No Action
Capital Costs: N/A
Annual O&M Costs: N/A
Present Worth (PW): N/A
The no action alternative is carried out through the screening process as required by the
NCP. The no action alternative assumes no further action at the site and is used as a
baseline to measure the other alternatives. Under this alternative, no action would be
taken hi terms of containment and treatment of the groundwater plume. Groundwater
contamination would remain and continue to migrate.
mgm95-DDMT Misc./OOl .WP5
2-13
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2.7.2 Alternative 2: Extraction Onsite, Air Stripping, and Discharge to
POTW
Capital Costs: $600,000
O&M: $270,000
PW: $6,000,000
The groundwater extraction system for Alternative 2 consists of eight wells located in
Dunn Field. The wells would be located to extract groundwater from the most
contaminated portion of the plume, according to existing data. The groundwater would
be removed from the eight wells and stored in a holding tank.
The extracted groundwater would be pumped from the holding tank to an air stripping
tower for removal of VOCs. The use .of a carbon treatment system will be dependent on
the concentration of VOCs in the air stream. Removal of heavy metals, if necessary,
would be performed after VOC treatment. The treated groundwater would be released
into the local sewer system, where it would be treated at the POTW.
2.7.3 Alternative 3: Extraction On/Offsite, Air Stripping, and
Discharge to POTW (Contingent Alternative)
Capital Costs: $600,000
O&M: $230,000
PW: $5,200,000
The pumping and treatment system for Alternative 3 is similar to Alternative 2 except for
the placement and pumping rate of the wells. Like Alternative 2, this alternative has
eight extraction wells, but with different locations. Two of the wells are located west of
Dunn Field, downgradient of the property boundary, with the remainder on DDMT
property. Alternative 3 would provide greater capture of the contaminated groundwater
off site. The treatment and handling of the groundwater would be similar to
Alternative 2.
2.7.4 Alternative 4: Extraction Onsite, UV/Oxidation, and Discharge to
POTW
Capital Costs: $830,000
O&M: $300,000
PW: $6,900,000
The extraction well system would be identical to Alternative 2. The extracted
groundwater would be treated by a UV/oxidation process using ultraviolet light, ozone,
and hydrogen peroxide to break down the VOCs into carbon dioxide, water, and
inorganic chlorides. Treatment for heavy metals, if needed, would follow UV/oxidation.
The treated water would be discharged to the POTW.
mgm95-DDMTMisc./OOI.WP5 2-14
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2.7.5 Alternative 5: Onsite Extraction, Air Stripping, and Discharge to
Surface Drainage Channel
Capital Costs: $470,000
O&M: $130,000
PW: $3,100,000
The extraction and treatment system of Alternative 5 is identical to Alternative 2.
However, the treated water would be discharged into the existing surface water drainage
system rather than to the POTW. Surface drainage channels exit from the northern and
western boundaries of Dunn Field. Both of these channels terminate at Cane Creek,
located north of Dunn Field. A National Pollutant Discharge Elimination System
(NPDES) permit would be required before discharge would be allowed.
2.7.6 Alternative 6: Extraction Onsite, UV/Oxidation, and Discharge to
Surface Drainage Channel
Capital Costs: $660,000
O&M: $160,000
PW: $3,900,000
Alternative 6 is similar to Alternative 4, except that the treated groundwater would be
discharged into the surface water drainage system discussed in Alternative 5.
2.7.7 Alternative 7: Extraction Onsite, Air Stripping, and Reinjection
ni
Capital Costs: $500,000
O&M: $150,000
PW: $3,500,000
Alternative 7 would extract groundwater from six wells on government property. The
extracted water would be treated by air stripping (similar to the treatment method in
Alternative 2), and treated for heavy metals, if needed. The treated water would be
reinjected into the Fluvial Aquifer upgradient from the extraction wells at Dunn Field.
Reinjection would be completed using four injection wells located on the eastern side of
Dunn Field. Pumps and piping would have to be installed to transmit the water from the
treatment site to the eastern side of Dunn Field.
mgm95-DDMTMisc./001.WP5 2-15
-------
2.7.8 Alternative 8: Extraction On/Offsite, and Discharge to POTW
(Preferred Alternative)
Capital Costs: $500,000
O&M: $250,000
PW: $5,600,000
Alternative 8 is the preferred alternative and is a hybrid of Alternative 3. However,
unlike Alternative 3, Alternative 8 places most of the groundwater recovery wells offsite
along the leading edge of the plume. This placement will be more effective in protecting
the Memphis Sand Aquifer from contaminants in the Fluvial Aquifer at OU-1.
Additionally, this alternative does not assume that pretreatment before discharge will be
required making it a less expensive alternative. However, this alternative uses the
treatment component of Alternative 3 as a contingency should pretreatment be required.
Alternative 8 would be used to contain the contaminated groundwater by inducing a
hydraulic barrier. The hydraulic barrier will be achieved by pumping the groundwater
from the containment wells placed along the leading edge of the plume. The leading .
edge of the plume will be located as part of the RI activities planned for OU-1. Data
gathered during the OU-1 RI will be used to locate the leading edge of the plume.
Leading edge identification and containment of the plume will be achieved in the
following manner:
• A groundwater recovery well will be installed onsite in the middle of the
plume to establish aquifer characteristics.
• Additional monitoring wells will be installed to establish the western edge
of the contaminant plume. The western edge will be established when
samples from these wells are uncontaminated.
• After the aquifer characteristics are established and the leading edge of the
plume is identified, additional groundwater recovery wells will be installed
as appropriate to contain the plume. These wells are located along the
leading edge of the plume and screened in the Fluvial Aquifer down to the
confining clay layer of the Memphis Sand Aquifer.
The groundwater and the associated contamination will be captured by the recovery wells
(see Figure 4). Calculations and modeling are performed to ensure that the zone of
recovery from each well overlaps. The spacing and pumping rate of the wells will be
such that the contamination should not move beyond the line of wells. Once the recovery
wells are operating, the system will be checked frequently (by comparing field data with
predicted model results) and any necessary adjustments made (including the installation of
additional recovery wells, if needed) to verify that the plume is contained.
mgm95-DDMTMisc./001.WP5 2-16
-------
N NOT TO
SCALE
PROPOSED
RECOVERY
WELLS
(TYP)
CONTAMINATION
"PLUME-
DUNN
FIELD
AERIAL VIEW OF
DUNN FIELD AND
PROPOSED
RECOVERY WELLS
LEGEND
GROUNDWATER
FLOW DIRECTION
PROPOSED
RECOVERY
WELL
RECOVERED GROUNDWATER
PIPED TO CITY SEWER
GROUNDWATER
FLOW
DIRECTION
FLUVIAL AQUIFER
\ \ \
CONTAMINATION \ \
\ I
"PLUME"
> •. \ \ \ \ '
. . , , \ \ \ \ \ \;
V
:\ ^ \ \ \ \ \ \ \ /
V '-. . -. \ \>
GROUNDWATER
FLOW DIRECTION
^^^^^^c^v\v^^^^^^^c<^^:^^x^^^^^^^^
\x^;'\<^C^X\v^^:\v^^^^c CLAY BARRIER N^^C:^X\NS%VXX:>;:
\\ \ -- \\\ \ V\\\\ X\ \\\ ••..":. \\ \. -• •, \ \ \ -: -.. \ \ \ '-. •-.. X\ \ ••- •:. \ \ \ '•• •, \\ \ '••
FIGURE 4
PROPOSED GROUNDWATER RECOVERY SYSTEM (OU-1)
Defense Depot Memphis, Tennessee
5-9-95 SRE70348.WP
2-17
-------
DDMT will obtain a discharge permit to allow the groundwater pumped from the wells to
be discharged into the municipal sewer system or POTW. The discharge permit will set
maximum levels for groundwater constituent concentrations. If the extracted groundwater
exceeds these limits, the treatment contained in Alternative 3 will be used. The cost of
Alternative 8, without the use of a contingency treatment remedy, assumes that the
groundwater will meet the City's permit limits and that no treatment will be needed.
2.8 Summary of the Comparative Analysis of Alternatives
This section of the interim ROD provides the basis for evaluating which alternative (a)
meets the threshold criteria of overall protection of human health and the environment,
EPA and TDEC approval, and compliance with applicable or relevant and appropriate
requirements (ARARs); (b) provides the best balance with respect to effectiveness,
reduction of toxicity, mobility, or volume through treatment, implementability, and cost;
and (c) satisfies community acceptance.
Federal law requires that nine criteria be used for evaluating the anticipated performance
of remedial actions. The nine criteria are described below, followed by an analysis of
the degree to which each alternative satisfies the criteria:
1. Overall Protection of Human Health and Environment-Assesses degree to
which alternative eliminates, reduces, or controls health and environmental
threats through treatment, engineering methods, or institutional controls.
2. Compliance with ARARs—Assesses compliance with federal and state
requirements.
3. Long-Term Effectiveness—Degree to which a remedy can maintain
protection of health and the environment once cleanup goals have been
met.
4. Reduction of Toxicity, Mobility, or Volume Through Treatment—Refers to
expected performance of the treatment technologies to lessen harmful
nature, movement, or amount of contaminants.
5. Short-Term Effectiveness-Length of time for remedy to achieve protection
and potential effects of construction and implementation of a remedy.
6. Implementability-Refers to the technical feasibility and administrative ease
of a remedy.
7. Cost-Weighing the benefits of a remedy against the cost of
implementation.
mgm95-DDMTMisc./001.WP5 2-18
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8. State Acceptance-Consideration of the state's opinion of the preferred
alternative.
9. Community Acceptance—Consideration of public comments about the
preferred alternative and about the proposed plan.
These nine criteria can be categorized into three groups. The first and second categories
are threshold criteria. The chosen alternative must meet the threshold criteria to be
eligible for selection. The third, fourth, fifth, sixth, and seventh criteria are considered
the primary balancing criteria. The final two criteria are termed the modifying criteria
and are evaluated after issuance of the Proposed Plan for public review and comment.
2.8.1 Analysis
2.8.1.1 Threshold Criteria
Overall Protection of Human Health and Environment. The preferred interim action
would contain the contamination plume and prevent it from migrating while removing a
portion of the contaminated groundwater. Because the plume is believed to have
migrated offsite, the preferred alternative must have extraction wells located offsite. The
wells in Alternatives 2, 4, 5, 6, and 7 are located onsite and would not sufficiently
contain the plume. This lack of containment would lead to further environmental effects
and would be a continual threat to human health. Alternative 1 offers no protective
measures for human health and the environment.
Alternatives 3 and 8 offer adequate degrees of protection by reducing and controlling the
risks through removal and containment. Alternatives 1, 2, 4, 5, 6, and 7 are not options
for this site because they do not adequately reduce the risks associated with the
contaminated groundwater.
Compliance with ARARs. Under the preferred alternative, groundwater will be
discharged to the POTW. Compliance issues are further discussed in Section 2.10.
2.8.1.2 Primary Balancing Criteria
Long-Term Effectiveness and Performance. Alternatives 3 and 8 should be effective in
reducing long-term contaminated groundwater levels and associated health risks. Because
of residual contamination, the size of the aquifer, and inherent complexities, it may not
be possible to completely remediate the aquifer to its original condition using technology
currently available. Additional actions will be necessary to provide long-term definitive
protection for OU-1.
mgm95-DDMTMisc./001.WP5 2-19
-------
Reduction of Toxicity, Mobility, or Volume of the Contaminants through Treatment.
The toxicity and volume of the contaminated groundwater would be reduced by the
groundwater extraction in Alternatives 3 and 8. Mobility of the contamination plume
would be restricted by the physical forces of the groundwater extraction. This hydraulic
barrier should prevent lateral and vertical movement of the contaminated groundwater,
thus reducing the threat to the Memphis Sand Aquifer.
Short-Term Effectiveness. Groundwater removal should contain the groundwater
contamination plume fairly rapidly and help to reduce further lateral contamination
migration. Implementing the preferred alternative would result in a reduction of the
potential effects to nearby residents from contaminants at Dunn Field.
Implementability. The groundwater recovery systems will be relatively simple to
implement. The technology and processes have been reliably demonstrated. Equipment
and materials are readily available. However, as previously stated, the Fluvial Aquifer
and the contaminated groundwater plume will have to be further characterized.
Cost. The cost analysis hi Alternative 3 includes the cost of well installation and O&M
cost of the air stripper. The capital costs are estimated at $600,000, O&M costs at
$230,000 and present worth cost at $5,200,000.
The cost of Alternative 8 is based on the installation of eight recovery wells. This cost
estimate assumes a quarterly sampling plan to ensure that the system is operating
efficiently and that no prior treatment before discharge will be required. However,
because of the uncertainties associated with groundwater recovery, additional wells may
be required that would affect the estimated cost. Additionally, the cost'of Alternative 8
does not include pretreatment costs. For Alternative 8, the capital costs are estimated at
$500,000, O&M costs at $250,000 and present worth cost at $5,600,000.
2.8.1.3 Modifying Criteria
State Acceptance. DDMT has been actively working with TDEC throughout the cleanup
process. TDEC supports this approach. However, information obtained during the RI
may suggest other alternatives that would involve the concurrence of the state.
Community Acceptance. Community response to the alternatives is presented in the
responsiveness summary, which addresses comments received during the public meeting
and the public comment period.
2.9 Summary of Selected Remedy
Through consideration of the requirements of CERCLA, the NCP, the detailed analysis
of alternatives and public and state comments, DDMT has selected an interim remedial
action for OU-1. Of the eight alternatives reviewed, only two were considered viable
mgm95-DDMTMisc./001.WP5 2-20
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options. Because "no action" does not address or rectify the problem and Alternatives 2,
4, 5, 6, and 7 do not contain the contamination plume, they are not considered
appropriate. The preferred alternative is Alternative 8, which is a hybrid of
Alternative 3. However, Alternative 8 puts more emphasis on plume containment and
does not assume that pretreatment before discharge will be required making it a less
expensive alternative. The placement of ground water recovery wells in Alternative 8 will
be more effective in protecting the Memphis Sand Aquifer from contaminants in the
shallow aquifer at OU-1.
If chemical analysis indicate that treatment is required before discharge, the treatment
option contained in Alternative 3 (the contingency remedy) will be used. The preferred
alternative for the IRA of the contaminated groundwater below Dunn Field is
Alternative 8—on/offsite extraction and POTW disposal. The criteria used to determine
whether the contingency remedy is implemented are the discharge limitations established
in the City of Memphis' discharge permit.
On the basis of current information, this alternative appears to offer the most reasonable
approach for the protection of the drinking water supply and containment of the plume.
Currently, groundwater recovery is the only appropriate alternative to contain the plume.
This alternative represents an interim action and is intended only to stabilize the site and
to prevent further degradation. However, with the additional information that will be
collected during the RI, other alternatives may become available. No conditions are
currently foreseen where the interim action will be inconsistent with, or preclude
implementation of, the final remedy.
The approach used to design and implement the preferred alternative will consist of the
following:
• Establishing the conditions that are believed to exist on the basis of
available information. Design will be based on expected conditions.
• Establishing, in advance, conditions that are reasonable deviations from the
probable conditions.
• Implementing the base design and monitor conditions.
• Implementing contingent designs as warranted by monitoring.
This approach is referred to as the observational method. The approach recognizes and
manages uncertainties inherent in groundwater remediation. Table 3 illustrates the
planned approach for managing uncertainties associated with the implementation of this
remedial action.
mgm95-DDMTMisc./001.WP5 2-21
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The observational method will be used during design and implementation and is not part
of the selection process for the IRA alternative. If changes to the selected remedy are
required, based on information obtained through the observational approach, then the
public will be made aware of these changes either through a fact sheet, explanation of
significant differences, or ROD Amendment.
Table 3
Observational Method for Dunn Field Groundwater Remediation
Probable
Condition*
8 recovery wells
needed
Pump at 75 gpm
Groundwater meets
City discharge
limits
Plume extends 600
ft west of Dunn
Field
Reasonable
Deviation*
12 recovery wells
needed
Pump at 125 gpm
Limits not met
Plume extends
1,200 ft west of
Dunn Field
Parameters to
Observe
Capture zone extent.
Observe water levels
in monitoring wells.
Capture zone extent.
Observe water levels
in monitoring wells.
Permit parameters
Data from RI
monitoring wells
Contingency Plan
Install additional
wells.
Pump at increased
rate; provide
adequate sewer
capacity.
Provide
groundwater
treatment.
Locate recovery
wells at western
extent of plume.
*Will be updated as additional information becomes available.
gpm— Gallons per minute
2.10 Statutory Determinations
DDMT, EPA, and TDEC concur that the extraction system (with the potential for
pretreatment, if necessary) will satisfy the CERCLA § 121 (b) statutory requirements of:
providing protection of human health and the environment, attaining applicable or
relevant and appropriate requirements directly associated with this action, being cost-
effective, using permanent solutions and alternative treatment technologies to the
maximum extent practicable, and including a preference for treatment as a principal
element.
2.10.1 Protection of Human Health and the Environment
Although the groundwater within the contaminated plume is not currently used as a
source of drinking water for the local residents, under future or other potential exposure
scenarios it presents a potential threat to human health and the environment. The interim
mgm95-DDMTMisc./001.WP5
2-22
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action remedy initiates protection of human health under the exposure scenarios through
mitigation of the spread of the plume and removing a portion of the contaminated
groundwater until a final action is determined. The remedy also provides protection to
the environment by providing the option of treatment of the extracted groundwater before
discharge, and effective management of all residual wastes generated during
implementation of the action.
The final cleanup levels for the groundwater are not addressed in this interim action
record of decision (ROD) because such goals are beyond the limited scope of this action.
The final cleanup levels will be addressed by the final remedial action ROD for the site.
2.10.2 Compliance with ARARs
The Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) of 1980 was passed by Congress and signed into law on December 11, 1980
(Public Law 96-510). The act was intended to provide for "liability, compensation,
cleanup, and emergency response for hazardous substances released into the environment
and the cleanup of inactive waste disposal sites." The Superfund Amendments and
Reauthorization Act (SARA), adopted on October 17, 1986 (Public Law 99-499), did not
substantially alter the original structure of CERCLA, but provided extensive amendments
to it. In particular, § 121 of CERCLA specifies that remedial actions for cleanup of
hazardous substances must comply with requirements or standards under federal or more
stringent state environmental laws that are applicable or relevant and appropriate to the
hazardous substances or particular circumstances at a site.
A listing of applicable or relevant and appropriate requirements (ARARs) (chemical-
specitic, location-specific, and action-specific) are provided in Tables 4, 5, and 6 of this
document. Discharge to the publicly owned treatment works (POTW) will be subject to
both the substantive and administrative requirements of the national pretreatment program
and all applicable state and local pretreatment regulations (Tables 4, 5, and 6). Should
treatment be required prior to discharge to the POTW, Alternative 3 will be implemented
as a contingency to provide groundwater treatment.
Alternative 3 uses an air stripper for the removal of volatile organic compounds (VOCs)
from the extracted groundwater. Air stripping is a viable treatment process for removal
of VOCs from water and will be used if treatment for VOCs is required.
2.10.2.1 Chemical-specific ARARs
The principal contaminants of concern in the groundwater plume west of Dunn Field are
presented in Table 1. Chemical-specific ARARs are shown in Table 4.
The City of Memphis Sewer Use Ordinance (March 1993) establishes maximum effluent
standards for discharge .of wastewater into the municipal sewerage system (Table 7).
Daily average maximum and instantaneous maximum concentrations are provided for
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NJ
i
N)
4^
Table 4
Preliminary Identification of Potential Chemical-specific ARARs for DDMT
Actions'
Discharge to
POTW'
Requirement
Treatment of pollutants that could pass
through the POTW without treatment,
interfere with POTW operation, or
contaminate POTW sludge is required.
Specific prohibitions preclude the
discharge of pollutants to POTWs that:
• Create a fire or explosion
hazard in the POTW
• Are corrosive (pH < 5 .0)
• Obstruct flow resulting in
interference
• Are discharged at a flow
rate and/or concentration
that will result in
interference
• Increase the temperature of
wastewater entering the
treatment plant that would
result in interference, but in
no case raise the POTW
influent temperature above
104°F(40°C)
Discharge must comply with the local
POTW pretreatment program,
including POTW-specific pollutants,
spill prevention program requirements,
and reporting and monitoring
requirements.
RCRA permit-by-rule requirements
must be complied with for discharges
of RCRA hazardous wastes to POTWs
by truck, rail, or dedicated pipe.
Prerequisites
'
Citation
40 CFR 403.5
See Table 6
40 CFR 403. 5 and
local POTW
regulations
•
40 CFR 270.60
Permits-by-rule
ARAR
Applicable
Comments
If any liquid is discharged to a POTW, these requirements
are applicable. In accordance with guidance, a discharge
permit may be required even for an onsite discharge.
because permitting is the only substantive control mechanism
available to a POTW.
Categorical standards have not been promulgated for
CERCLA sites, so discharge standards must be determined
on a case-by-case basis, depending on the characteristics of
the waste stream and the receiving POTW. Some
municipalities may have published standards for non-
categorical, non-domestic discharges. Changes in the
composition of the waste stream due to pretreatment process
changes or the addition of new waste streams may require
renegotiation of the permit conditions.
Local (City of Memphis) requirements for discharge to a
POTW are summarized in Table 6 for the constituents of
concern shown in Table 1 .
DDMT is applying for a City discharge permit.
Notes:
v
•These regulations apply regardless of whether the remedial action discharges into the sewer or trucks the waste to an inlet to the sewage conveyance system located "upstream" of the POTW.
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2-24
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Table 5
Preliminary Identification of Potential Location-specific ARARs at DDMT
Location
1.
2.
3.
4.
5.
Within 61 meters (200 feet)
of a fault displaced in
Holocene time
Area affecting stream or river
Memphis/Shelby County
Within 100-year floodplain.
Wetlands
Requirement
New treatment, storage, or disposal
of hazardous waste prohibited.
Action to protect fish or wildlife.
Ozone, carbon monoxide, and lead
air pollutants for Memphis/Shelby
County have been designated a non-
attainment area.
Facility must be designed,
constructed, operated, and
maintained to avoid washout.
Action to minimize the destruction,
loss, or degradation of wetlands
Action to prohibit discharge of
dredged or fill material into wetland
without permit
Prerequisite^)
RCRA h;izardous waste; treatment,
storage, or disposal
Diversion, channeling, or other
activity tiat modifies a stream or
river and affects fish or wildlife
RCRA hazardous waste; PCB
treatment storage, or disposal
Wetlands as defined by Executive
Order 1 1 990 Section 7
Citation
40CFR264.18(a)
Fish and Wildlife
Coordination Act (16
USC 661 et seg-); 40
CFR 6.302
State of TN Air Code
40 CFR 264. 18(b);
40 CFR 761. 75
Executive Order
11990, Protection of
Wetlands (40 CFR 6,
Appendix A)
Clean Water Act
Section 404; 40 CFR
Pans 230, 231
ARAR
Not ARAR
Not ARAR
Not ARAR
Not ARAR
Not ARAR
Comments
Shelby County is not listed in 40 CFR 264,
Appendix VI, as being seismically active.
The Fish and Wildlife Coordination Act
requires consultation with the Department of
Fish and Wildlife before taking any action that
would alter a body of water of the United
States.
Memphis-Shelby County Health Department
has adopted Tennessee Air Code.
Surface elevations at DDMT (276 to 316 feet
NGVD) exceed the average Mississippi River
alluvial valley flood levels of 185 to 230 feet
NGVD. The Flood Insurance Rate maps,
published by Federal Emergency Management
Agency and revised August 19, 1985, indicate
that DDMT is not within the 100- or 500-year
floodplain, but is in Zone C — "Areas of
Minimal Flooding."
Ui
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Table 6
Preliminary Identification of Potential Action-specific ARARs for DDMT
Page 1 of 2
Actions"
Air Stripping
Requirement
Design system to provide odor-free
operation.
Obtain Memphis/Shelby County Health
Department construction/operating
permit.
Estimate total VOC emissions.
File an Air Pollution Emission Notice
(APEN) with the State to include
estimation of emission rates for each
pollutant expected.
Include with filed APEN the following:
• Modeled impact analysis of source
emissions
• Provide a Best Available Control
Technology (BACT) review for the
source operation
Predict total emissions of volatile
organic compounds (VOCs) to
demonstrate that emissions do not
exceed 450 Ib/hr. 3,000 Ib/day,
1U gal. /day, or allowable emission
levels from similar sources using
Reasonably Available Control Tech-
nology (RACT).
Verify that emissions of VOCs do not
exceed levels expected from sources in
compliance with hazardous air pollution
regulations.
Prerequisites
Emission requirements for
groundwater treatment systems
are handled individually.
Groundwater contains regulated
air pollutants.
This additional work and
information is normally
applicable to sources meeting die
"major" source criteria and/or to
sources proposed for
nonattainment areas.
Source operation must be in an
ozone nonattainment area.
Citation
CAA Section 101"
TCA 1200-3-9(l)(a)
1990 CAAA Section 302(g)
TCA 1200-3-9(1 l)(b)14.(ii)
40 CFR 52"
40 CFR 52"
40 CFR 52"
40 CFR 61"
ARAR
Applicable
Applicable
Applicable
Applicable
Relevant and
Appropriate
Applicable
Relevant and
Appropriate
Comments
Odor regulations are intended to limit nuisance
conditions from air pollution emissions.
Each construction-operating permit is based on "Best
Available Control Technology."
Any source emitting more than 100 tpy VOCs is
classified as major and requires agency review and a -
potential permit.
State will have particular interest in emissions for
compounds on its hazardous, toxic, or odorous list.
Preliminary meeting with State prior to filing APEN is
recommended in the regulation. Meeting would identify
additional issues of concern to the State.
State may identify further requirements for permit
issuance after first review. These provisions follow the
federal Prevention of Significant Deterioration (PSD)
framework with some modifications. Additional
requirements could include ambient monitoring and
emission control equipment design revisions to match
Lowest Achievable Emission Requirements (LAER).
While a permit is not required for an onsite CERCLA
action, the substantive requirements identified during the
permitting process are applicable.
The control technology review for this regulation
(RACT) could coincide with the BACT review
suggested under the PSD program.
Any source emitting the regulated compound(s) is
subject to these regulations. However, some of the
specific regulations further restrict the scope of
applicability.
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Table 6
Preliminary Identification of Potential Action-specific ARARs for DDMT
Page 2 of 2
Actions*
Requirement
Prerequisites
Citation
ARAR
Comments
Air Stripping
Estimate HAP emissions.
Groundwater contains HAPs.
Title III, 1990 CAAA
Section 112
TCA 1200-3-9(ll)(b)14.(i)
Applicable
If hazardous air pollutants (HAPs) are greater than a
major rate, air permit and/or application of Maximum
Available Control Technology (MACT) may be
required. HAPs exceed 25 tpy aggregate HAPs or
10 tpy for a single HAP.
Groundwater
Cleanup
N>
Maximum contaminant level goals
(MCLGs), established under SDWA,
that are set at concentrations above zero
shall be attained if relevant and
appropriate to the circumstances of the
release. Where MCLGs for a
contaminant have been set at a
concentration of zero, the MCLs for
that contaminant shall be attained.
Groundwater standards established
under RCRA shall be attained if
relevant and appropriate to
circumstances of the release.
Groundwater is a currer.t or
potential source of drinliing
water.
40 CFR 300.430 of NCP
Relevant and
Appropriate
No MCLG or maximum
contaminant level (MCL) has .
been established for contaminant
of concern.
Cleanup value for lead in
groundwater used for drinking is
not an MCL, but is established as
an action level.
40 CFR 264.94
USEPA memo dated
June 21, 1990, from Henry
Longest to Patrick Tobin
Tennessee adopted guidelines equivalent to federal
guidelines. The interim remedial action will not address
groundwater cleanup ARARs. The final remedial action
will.
Memo recommended a final action level for lead of 15
ppb.
Groundwater
Withdrawal
Water withdrawal registration is
required for wells or systems that pump
more than 50,000 gallons per day.
Water Withdrawal
Registration Act of 1963-
Chapter 8-Water Resources
Div., Section 69-8-105
Relevant and
Appropriate
Total flow from all recovery wells may be up to 1 mgd.
Notes:
"Action alternatives from ROD keyword index.
'All of the Clean Air Act ARARs that have been established by the federal government are covered by matching state regulations. The state has the authority to manage these programs through the approval of
its implementation plans (40 CFR 52, Subpart G). As of January 1996, the Tennessee SIP is complete, with EPA action pending.
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Table 7
Maximum Effluent Standards for Discharge of Waste into the Municipal Sewerage System
Daily Average'1' Instantaneous
Maximum Concentration Maximum Concentration
Constituent mg/L mg/L
Metals
Arsenic 1.0 2.0
Barium
Chromium (hexavalent) 1.0 2.0
Chromium (total) .5.0 10.0
Lead(2)
Nickel 5.0 10.0
Volatile Organic Compounds
l,l-Dichloroethene(3)
1,2-Dichloroethene (total)(3)
Tetrachloroethene(4)
^ Trichloroethene(3)
to Carbon tetrachloride(3)
QQ ___^
Source: City of Memphis, Sewer Use Ordinance, March 1993
Notes:
'Based on 24-hour flow-proportionate composite sample
2Cadmium, mercury, and lead discharges are severely restricted due to limitations placed on the disposal of sewage sludge
containing cadmium, mercury, and/or lead. Actual allowable discharge concentrations for these constituents will be determined
on a case-by-case basis.
3No person shall discharge wastewater containing any of the materials listed herein into the municipal sewer system
or shall have any connection to the municipal sewer system without obtaining written permission from the Approving
Authority.
4This parameter is not included in City of Memphis Sewer Use Ordinance.
mgm95-DDMT-MISC2/005.doc
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arsenic, chromium, lead, and nickel. With the exception of tetrachloroethene, the
remaining VOCs in Table 1 and barium cannot be discharged without written permission
from the approving authority. Tetrachloroethene is not included in the City of Memphis'
ordinance. The final permit for city discharge will be negotiated as part of this action.
2.10.2.2 Location-specific ARARs
Location-specific requirements "set restrictions upon the concentration of hazardous
substances or the conduct of activities solely because they are in special locations" (53
Fed. Reg. 51394). Table 5 lists location-specific ARARs that might be pertinent to this
remedial action.
2.10.2.3 Action-specific ARARs
Performance, design, or other action-specific requirements set controls or restrictions on
particular kinds of activities related to the management of hazardous waste (52 Fed. Reg.
32496). Selection of a particular remedial action at a site will invoke the appropriate
action-specific ARARs that may specify particular performance standards or technologies,
as well as specific environmental levels for discharged or residual chemicals. Federal
and state regulations appear in Table 6 and are summarized below.
Well Construction. State of Tennessee requirements for water production well
construction are promulgated under Tennessee Code Annotated (TCA) Section 70-2307
Chapter 400-2-2: however, these requirements do not apply under the exemptions stated
in TCA Section 68-46, Chapter 1200-4-9.01(b) whereby wells otherwise regulated by the
State, hi this case through CERCLA, are not considered water production wells.
However, the Memphis and Shelby County Health Department Pollution Control Section
has promulgated requirements and regulations in the Rules and Regulations of Wells in
• *>wv^ -w». .-.-^ . £, ____ _ ,. ._| ______ _ __ -. ___ ____, __
specific well siting and construction requirements.
Pumping. Under the Water Withdrawal Registration Act of 1963, Chapter 8-Water
Resources Division, Section 69-8-105 requires that any person withdrawing 50,000 or
more gallons per day (gpd) of water from any source register with the division of water
resources. A permit is not required. On the basis of an anticipated pumping rate that
may reach 1 million gpd for the recovery well system, it is anticipated that registration
will be required.
The action-specific ARARs for direct discharge of treatment system effluent are shown in
Table 6. DDMT is applying for a City discharge permit. Discharge limits will be
specified in the permit.
2.10.3 Cost-Effectiveness
The interim action remedy uses a commercially tested technology that affords a high level
of effectiveness proportional to its costs so that the remedy represents reasonable value.
This action will use a relatively inexpensive technology to mitigate the spread of the
mgm95-DDMTMisc./001.WP5 2-29
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contaminated groundwater. This limited scale containment operation should reduce the
cost of the overall remediation of the groundwater by retarding the migration of the
contaminant plume.
2.10.4 Use of Permanent Solutions and Alternative Treatment
Technologies
The interim action is designed to minimize the possibility of contamination of the area's
drinking water supply. This is not the final action planned for the groundwater
contamination. Follow-on activities include monitoring the groundwater plume and its
response to the IRA. Once the plume has been fully characterized, subsequent action
may be taken to provide long-term definitive protection, including remediation of source
areas. To the extent possible, the interim action will not be inconsistent with, nor
preclude implementation of, the expected final remedy.
2.10.5 Preference for Treatment as a Principal Element
This interim action satisfies the statutory preference for treatment of the discharged
effluent (through, at a minimum, treatment at the POTW) as a principal element of the
containment system. If necessary, onsite treatment will be performed if needed to meet
permit criteria.
2.11 References
CH2M HILL, December 1994. Proposed Groundwater Action Plan. Defense Depot
Memphis, Tennessee.
Engineering-Science, Inc., August 1993. Engineering Report—Removal Action for
Groundwater. Prepared for U.S. Corps of Engineers, Huntsville Division.
Engineering-Science, Inc., July 1994. Focused Feasibility Study: Dunn Field. Prepared
for U.S. Corps of Engineers, Huntsville Division.
Environmental Science and Engineering, Inc., July 1994. Groundwater Monitoring
Results Report for DDMT. Prepared for U.S. Army Corps of Engineering Huntsville
Division.
Law Environmental, August 1990. Remedial Investigation at DDMT, Final Report.
Parks, William S., 1990. Hydrogeology and Preliminary Assessment of the Potential for
Contamination of the Memphis Aquifer in the Memphis Area, Tennessee. Water
Resources Investigations Report 90-4092. Prepared in cooperation with the City of
Memphis, Memphis Light, Gas and Water Division.
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Part 3
Responsiveness Summary
-------
Responses to Written Comments Received at
Public Hearing on the Federal Facilities Agreement and
Proposed Interim Remedial Action
December 20, 1994
1. Comments Received from Roosevelt Sanders Jr., 2592 Fontaine Road, Memphis,
TN 38106
It is my suggestion that proposed remedial action should include a larger area of testing.
The land south of DDMT, at one time, was used as a dump. A record check should be
done to determine whether DDMT has ever used that area for dumping purposes. My
father told me, in 1964 (when I moved hi that area), that the homes were built on top of
a dump.
It seems to me that the IRA is using the Band-aid approach to what could possibly be a
serious problem.
DDMT RESPONSE: The Installation Services records were checked and no records of
any dumping in this landfill were found. Long-time employees of DDMT, who are
familiar with the disposal activities throughout its operational history, were interviewed
concerning their knowledge of any DDMT use of the land to the south of its boundaries
for dumping purposes. None of the employees had any knowledge of DDMT disposing
of any materials south of DDMT. Specifically, Mr. Ulysses Truitt, who worked at
DDMT for more than 30 years, indicated with certainty that no materials were disposed
of in the area south of DDMT. Historically, DDMT disposed of materials either onsite or
in permitted landfills operated by the City of Memphis.
As part of the remedial investigation, monitoring wells are proposed to be installed south
of DDMT to determine if any offsite sources are contributing to the contamination under
DDMT. These monitoring wells may also intercept any contaminants that might be
migrating from the dump reported to be south of DDMT.
The Interim Remedial Action (IRA) was not designed to address dumping that was
reported south of DDMT in the 1960s. Rather, the IRA was intended as an interim
action to address contamination that appears to be migrating west of Dunn Field. This
action will be consistent with the final remedy, and is intended to meet the objective of
protecting the Memphis Sand Aquifer. The focus of the IRA is on Dunn Field and
contamination migrating to the west of the Field, not on a landfill reported to be south of
DDMT. By implementing a groundwater IRA, contaminants will be incrementally
removed from the Fluvial Aquifer and will be contained to mitigate migration toward the
Allen Well Field. The IRA will be implemented expeditiously and will continue to
operate until a final remedy is in place.
mgm95-DDMT-Misc/004.WP5 3-1
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Concerns about any material that may have been disposed of at the landfill south of Alcy
Road are valid, but are misdirected at DDMT because it was not a contributor.
However, Mr. Sanders may direct his concerns to the Tennessee Department of
Environment and Conservation (TDEC). That agency is concerned with contamination
resulting from past landfill practices. It is recommended that staff in TDEC's Memphis
and Nashville offices be contacted, starting with the Divisions of Superfund and Solid
Waste.
2. Comment Received from Dorothy Brooks, 1802 Wendy Drive, Memphis TN
38114
I live hi the Nob Hill Subdivision, south of Alcy Road. I understand that our subdivision
was built on landfill. Therefore, anything and all lands of materials were probably
dumped there.
Because of the large number of health problems that have occurred and are occurring, the
residents should be informed of the type of dangers that could possibly be present.
I am again requesting that the soil/water in the above stated community be tested.
DDMT RESPONSE: Ms. Brooks' concerns are valid, but are misdirected toward
DDMT, since it does not have the authority or jurisdiction to make an initial investigation
of a landfill that is not on DoD property. Because, to the best of its knowledge, DDMT
has not disposed of any material in the landfill to the south of its boundaries, it is not
currently involved in investigating any alleged contamination resulting from past disposal
practices at this site. However, it is recommended that Ms. Brooks convey her concerns
to other responsible agencies. TDEC may have a permit file on the old landfill. That
file may either be in the field office in Memphis or in the central office hi Nashville.
The permit file should contain an indication of the types of materials that the landfill was
permitted to receive, and may contain some inspection reports.
Other agencies that may provide assistance include the Environmental Protection Agency
(EPA), Region IV, in Atlanta, Georgia; the City of Memphis; the Memphis and Shelby
County Health Department; Memphis Light Gas and Water (MLGW); and the Memphis
State University Ground water Institute. Each of those agencies has specific areas of
authority, jurisdiction, and resources.
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