United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R03-91/119
August 1991
Superfund
Record of Decision:
USA Letterkenny Southeast
Area, PA
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R03-91/119
3. Redpienf* Accession No.
— •ndsuMte
ERFUND RECORD OF DECISION
™ Letterkenny Southeast Area, PA
First Remedial Action
&. RBportOete
08/02/91
7. Auftorts)
OvQirasUlon RspL No.
ft. Performing 0>g«lna»»on Name aid Address
10. Pro|ecVTs«k/Work Unit No.
11. Centracl(C) or Orant(G) No.
(C)
(G)
12. Sponeortr« Organization Nune and Adottw*
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
IX Type of Report* Period Covered
800/000
14.
IS. Supple
iiyNo
16. Abstract (Limit: 200 word*)
The USA Letterkenny Southeast Area site is on a 19,500-acre active U.S. Army facility
in Chambersburg, Franklin County, Pennsylvania. Land use in the area is primarily
agricultural with scattered residences and military facilities. Ground water flowing
beneath the Southeast site discharges into two nearby streams. Drinking water in the
33 residences located within a 3-square-mile radius of the facility has been affected
• ground water contamination from the site. Since 1942, the U.S. Army has used the
Aitheast Area to overhaul, rebuild, and test wheeled and tracked vehicles; distribute
Class III chemicals and petroleum; and store, maintain, demilitarize, modify, and
demolish ammunition. These activities past industrial have involved the use and
disposal of TCE, solvents, hydrocarbons, and metals. As a result of a Federal
Interagency Agreement, EPA conducted several investigations which identified
VOC-contamination of onsite soil in the K Area associated with the various burial
trenches, pits, and landfills used for hazardous waste disposal. This Record of
Decision (ROD) addresses contaminated soil in the Southeast Area, and is the first
operable unit for that area. Future RODs will address other contaminant source areas
(See Attached Page)
17. Document Analysis a. DMCfiptora
Record of Decision - USA Letterkenny Southeast Area, PA
First Remedial Action
Contaminated Medium: soil
Key Contaminants: VOCs (TCE, xylenes)
b. Uenlffien/Opan-Endad Terrna
c. COSATI FieM/Group
19. Security CUM (TM» Report)
None
20. Security Class (This Page)
None
21. No. of Page*
48
22. Price
(See ANSI-Z3S.18)
See Inttrvction* on flferane
OPTIONAL FORM 272 (4.77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/R03-91/119
USA Letterkenny Southeast Area, PA
** st Remedial Action
1—tract (Continued)
and ground water. The primary contaminants of concern affecting the soil are VOCs
including TCE and xylenes.
The selected remedial action for this site includes excavating and treating onsite
8,000 cubic yards of VOC-contaminated soil using low temperature thermal treatment;
controlling vaporized contaminants using a secondary high-temperature combustor, or
bollecting these vapors by adsorption onto activated carbon; backfilling the residual
ash onsite; disposing of the residual carbon offsite; and conducting soil monitoring.
The estimated present worth cost for this remedial action is $1,539,191. There are no
O&M costs associated with this remedial action.
PERFORMANCE STANDARDS OR GOALS: Soil excavation levels will be set at 225 ug/kg for all
contaminants to ensure that the levels of indicator chemicals in ground water will meet
the State ground water requirements.
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RECORD OF DECISION
ACCELERATED REMEDIAL ACTION
SOUTHEASTERN AREA
OPERABLE UNIT ONE: K AREA CONTAMINATED SOILS
LETTERKENNY ARMY DEPOT
CHAMBERSBURG, PENNSYLVANIA
June 27, 1991
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TABLE OF CONTENTS
A. DECLARATION 1
B. DECISION SUMMARY 3
1 SITE NAME, LOCATION, AND DESCRIPTION 3
1.1 SITE BACKGROUND 3
1.2 SITE LOCATION 3
1.3 SITE DESCRIPTION 6
2 SITE HISTORY AND ENFORCEMENT ACTIVITIES . 11
2.1 SITE HISTORY 11
2.2 DESCRIPTION OF INVESTIGATIVE HISTORY 12
2.3 CERCLA ACTIVITIES 18
3 HIGHLIGHTS OF COMMUNITY PARTICIPATION 18
4 SCOPE AND ROLE 20
5 SUMMARY OF SITE CHARACTERISTICS 21
5.1 SITE CONTAMINATION AND AFFECTED MEDIA. ....... 21
5.2 SOURCES OF CONTAMINATION 21
5.3 LOCATION OF CONTAMINATION 21
5.4 POTENTIAL ROUTES OF MIGRATION 22
6 SUMMARY OF SITE RISKS 22
6.1 EXPOSURE ASSESSMENT 22
6.2 RISK CHARACTERIZATION 23
6.3 RISK CONCLUSIONS 23
7 DESCRIPTION OF ALTERNATIVES 24
7.1 NO ACTION RESPONSE 25
7.2 CONTAINMENT RESPONSE 27
7.3 THERMAL TREATMENT RESPONSE 29
7.4 INNOVATIVE TECHNOLOGY RESPONSE 29
8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 30
8.1 EVALUATION CRITERIA 30
8.2 ANALYSIS OF ALTERNATIVES .32
9 SELECTED REMEDY 34
9.1 RATIONALE FOR SELECTION OF PREFERRED ALTERNATIVE . . 34
10 STATUTORY FINDINGS 37
; 10.1 PROTECTION OF HUMAN HEALTH AND ENVIRONMENT 37
10.2 COMPLIANCE WITH ARARS 37
10.3 COST-EFFECTIVENESS 39
10.4 UTILIZATION OF PERMANENT SOLUTIONS 39
C. RESPONSIVENESS SUMMARY 41
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LIST OF TABLES
Table Title Page
2.1 LEAD CERCLA Reports for SE/PDO Areas 15
7.1 Summary of Remedial Alternatives 26
8.1 Summary of Detailed Analysis 35
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LIST OF FIGURES
Figure Title Page
1.1 CERCLA Remedial Process for a Site 4
1.2 Location Hap of LEAD and Vicinity 5
1.3 Generalized Geologic Map of LEAD 7
1.4 Predominant Faults Associated with SE Area . 8
1.5 General Soils Map I'D
2.1 Drainage Basin Map 13
2.2 Source Areas within K Area 14
2.3 Location of Soils to be Remediated 19
7.1 Cross-Section of Multimedia Cap 28
7.2 Process Schematic for LTT 31
9.1 Process Schematic for LTT 38
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DECLARATION FOR THE RECORD OF DECISION
ACCELERATED REMEDIAL ACTION
SOUTHEASTERN AREA
OPERABLE UNIT ONE: K AREA CONTAMINATED SOILS
LETTERKENNY ARMY DEPOT
Site Name and Location
U.S. Department of Army
Southeastern Area (SE), Letterkenny Army Depot (LEAD) ^
Franklin County
Chambersburg, Pennsylvania
Statement of Basis and Purpose
This decision document presents the selected final remedial
action for contaminated soils in the K Area, within the Southeastern
Area at Letterkenny Army Depot, which was chosen in accordance with
the^requirements of the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA) and, to
the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision document explains
the factual and legal basis for selecting the final remedy for this
site. This decision is based on the administrative record.
The U.S. Environmental Protection Agency (EPA), Region III and
the Pennsylvania Department of Environmental Resources (PADER)
concur with the selected remedy. The information supporting this
remedial action decision is contained in the administrative record
for LEAD.
Assessment of the Site
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the final response
action selected in this Record of Decision (ROD), may present an
imminent and substantial threat to public health, welfare, or the
environment.
Description of the Selected Remedy
This operable unit is the first operable unit of a possible
three operable units for the Southeastern Area. The first operable
unit at this site will provide source control for the contaminated
soils in the K Area, thereby minimizing the contaminant migration
from the soils into the groundwater at this site. The contaminated
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soils are a principal threat in the K Area. Operable unit number
two will address other contamination source areas and operable unit
number three will address groundwater contamination and a final
remedial response action will be selected for this media.
The remedial action described herein will not require
long-term management due to the treatment of the contaminated soils
in the K Area. The major components of the selected remedy include
the following:
- excavation of 8000 cubic yards of contaminated soils
in the K Area;
- thermal treatment of contaminated soils at a "'
temperature not greater than 450 F;
- destruction of volatilized contaminants by a secondary
high-temperature combustor or adsorption of
volatilized contaminants onto activated carbon;
- analysis of representative samples of treated soils
and comparison with treatment criteria;
- proper management of treated soils.
Declaration of Statutory Determinations
The selected remedy 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. This remedy utilizes permanent
solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable, and it satisfies the
statutory preference for remedies that employ treatment that reduce
toxicity, mobility, or volume as their principal element.
Lewis D. Walker Date
Deputy Assistant Secretary of the Army
for Environment, Safety, and Occupational
Health _
Edwin B. Erickson Date
Regional Administrator
U.S. Environmental Protection Agency, Region III
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1 SITE NAME, LOCATION, AND DESCRIPTION
1.1 SITE BACKGROUND
The U.S. Army Toxic and Hazardous Materials Agency (USATHAMA)
is currently performing Remedial Investigation/Feasibility Study
(RI/FS) activities as required under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA) at U.S.
Department of Army (Army), Letterkenny Army Depot (LEAD) in
Chambersburg, Pennsylvania. Soil contamination for volatile organic
compounds (VOCs) above the action levels designated by the +
Pennsylvania Department of Environmental Resources (PADER) and the
U.S. Environmental Protection Agency (EPA) has been detected in the
K Area which is within the Southeastern Area (SE) of the depot.
Previous investigations by USATHAMA, Battelle, Roy F. Weston,
and Environmental Science & Engineering, Inc. (ESE) have defined
three areas within the K Area where VOC contamination of the soil
exists. These source areas are K-l, K-2, and K-3. Since
contamination of area K-2 has been linked to the migration of
contaminants from area K-l, K-2 will be considered a part of K-l.
The Record of Decision (ROD) described in this document encompasses
all three areas which hereafter will be referred to as the K Area.
This document is the Army's ROD for the identification and
implementation of a final soil remedial action in the K Area at
LEAD. The purpose of this ROD is to: certify that a selected remedy
complies with CERCLA, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), and state law, outline technical
goals of the selected remedy, provide background information for the
contaminated site, summarize the analysis of the remedial action
alternatives which were considered, and explain the rationale for
the selected remedy. This ROD will document a final accelerated
remedial action plan for operable unit one: K Area Contaminated
Soils (OU1). The remaining final remedial actions and RODs
currently planned for LEAD will be executed following the completion
of the RI/FS. Figure 1.1 outlines the remedial process mandated by
CERCLA for a site.
- 3
1.2 SITE LOCATION
LEAD, formerly known as Letterkenny Ordnance Depot, is located
in south-central Pennsylvania in the central portion of Franklin
County; in Letterkenny, Greene, and Hamilton Townships, about 5
miles north of the city of Chambersburg (Figure 1.2). The
installation occupies 7,899 hectares (19,520 acres) situated in the
western side of the Cumberland Valley, which is characterized by
gently rolling terrain underlain by folded and faulted geologic
formations. Approximately 5600 civilians and 140 military personnel
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IL
• _
ii
ii
ii
i;
i!
II
FIGURE 1-1
The Remedial Process
i:-:-:-:-:-:
::Pre-RernedJa{>
"Tl
i
-Preliminary Assessment
- Site Investigation
- MRS Evaluation
- NPL Listing
Preliminary Identification of site
hazards and evaluation of the need
for action under Superfund
remedial program
i.HemedlatlavestJgaUon^FeaslbUlty Study:;:
•
-Scoping
- Site Char-
acterization
- Baseline
Risk
Assessment
-Treatablllty
Studies
- Development
and screening of
alternatives
- Detailed Analysis
of Alternatives
Gather Information sufficient to
support an Informed risk
management decision regarding
which remedy appears to be the
most appropriate for a given site
Identification of
Preferred Alternative
.
Record) of Decision (ROD),
"
i
- Remedial Design.
- Remedial Action
- Operation and Maintenance
- Deletion from NPL
Make Initial Identification of preferred
alternative based upon preliminary
balancing of tradeoffs among
alternatives using the nine criteria
.\ /- - » Proposed Plan -''- "' •
T
Public Comment
f
T
_ _
Remedy selection
-^
•
^pliBf osent'preierreid alteitiatlvjerfSlyw
Minimum 2 1 day public comment
period held on the Proposed Plan,
RI/FS, and other contents of i
the Administrative Record file
Make final determination on remedy
Certify that
-- --. ••••••••••••••••'•
:.-> .:.*-..:: .; -^jiJv««i<.rf!:..:'..>fci-::»;>
remedy, pro vlda background
'thf 6r miattofi ;on':ttie slf e
explain th»TaUonale:f;or Wrt . ,.v
:eelecled;^S^|;.%^^^:|^^^0|||^^
Design and construct remedy utilizing
Information contained In the ROD
and other relevant documents
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WE s r
VI MCIMI A
<-
•«• •«"«
flNMiTCV»HI»
ni I)•!<•«•
LETTERKENNY
•
Nf »
MUlttuM
/yy
/ V I N 6 I M I A
S 10 MILES
a
& 10 KILOMETERS
SOURCES: ••lull*. 1M1*.
ESE. !««••
Figure 1.2
LOCATION MAP OF LEAD AND VICINITY
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Lellerkenny Army Depot
U.S/Army
Toxic and Hazardous Materials Agenc
Aberdeen Proving Ground, Maryland
•
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are employed at LEAD, .and more than 1862 buildings and structures
are located on the installation with roughly 1096 miles of road.
The population for Franklin County is about 115,000.
Chambersburg is the largest town and county seat, with 17,000
inhabitants. Thirty-three residences are located within a
3-square-mile (mi2) area adjacent to the K Area with the SE Area at
LEAD. Assuming each home contains 3.8 people, the population is
approximately 126 people.
1.3 SITE DESCRIPTION
. • r
LEAD is located in the Great Valley section of the Valley and
Ridge physiographic province. This area, known locally as the
Cumberland Valley, extends northeast to southwest across the central
part of Pennsylvania. Figure 1.3 is a generalized geologic map of
the northern part of the Great Cumberland Valley, including LEAD.
1.3.1 GEOLOGICAL CHARACTERISTICS
The five formations that occur in the vicinity of LEAD are the
shales of the Hartinsburg Formation, the limestones of the
Chambersburg Formation, the limestones of the St. Paul Group, the
dolomites of the Pinesburg Station Formation, and the limestones and
interbedded dolomites of the Rockdale Run Formation. The
Chambersburg Formation, St. Paul Group, Rockdale Run Formation, and
Pinesburg Station Formation occur in the SE Area with the St. Paul
Group occurring in the K Area. These geologic formations are
fractured and deformed to varying degrees from past geologic
activity.
The Martinsburg Formation, predominately a black shale, and the
Pinesburg Station Formation, predominately a dolomite, appear to be
more resistant to erosion than the other rock units and tend to form
hills. However, the Chambersburg Formation, St. Paul Group, and
Rockdale Run Formation are limestones that form the valley floor of
the SE Area at LEAD and have associated karst features (e.g.
sinkholes and internal drainage). The limestones of the St. Paul
Group are present within the K Area. The carbonate and shales in
the SE Area are distorted by structural deformations that formed the
Great Valley. The predominant faults associated with the SE Area of
LEAD are the Pinola and Letterkenny Faults (see Figure 1.4).
1.3.2 GROUNDWATER CHARACTERISTICS
Groundwater flow in the Ordovician carbonates (Chambersburg
Formation, St. Paul Group, Pinesburg Station Formation, and Rockdale
Rum Formation) tends to parallel the strike of the bedding and
joints, fractures, and major fault structures. In the Martinsburg
Formation, extensive fracturing causes groundwater flow to resemble
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GEOLOGIC MAP OF BLUE RIOGE AND GREAT VALLEY. PENNSYLVANIA
(••M4 wi 1NO »A Ototog* Mw wWi nttotom by J. ClMk. J. ft**.
J. FiwwtiH. o. MWLIOMM. A. Okwnu MM V Meat)
LETTERKENNY
ARMY DEPOT
Figure 1.3
GEOLOGIC MAP OF LEAD AND
SURROUNDING AREAS
SOURCE: Weston. 1984.
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Letterkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
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I INSTALLATION BOUNDARY
—— ROADS
RAILROAD TRACKS
FORMATIONAL CONTACT
FAULT
PINESBURG STATION FORMATION
MARTINS8URG FORMATION
ST. PAUL GROUP
CHAMBERSBURG FORMATION
ROCKOALE RUN FORMATION
Figure 1.4
.GEOLOGIC MAP SHOWING APPROXIMATE
FORMATIONAL CONTACTS AND FAULTS
IN THE SE AREA
SOURCES: B*chtr and Taylor. 1»M.
EPMEPIC. 19(7. REVISED 8Y ESE. 1M7.
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Letterkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
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classical porous media flow patterns and is normal to the
equipotential lines of the groundwater gradient.
The Martinsburg Formation is a thin-bedded, black, steeply
inclined, fissile shale of late Ordovician age. It contains
interbedded layers of sandstones, siltstones, and minor carbonates.
Wells completed within the Martinsburg Formation yield from 50 to
150 gallons per minute (gpm).
The Middle Ordovician Chambersburg Formation is a dark gray,
thick- to thin-bedded limestone that weathers into cobbles with
moderate groundwater yields of approximately 11 to 35 gpm.
The Middle Ordovician St. Paul Group is a dark gray, thin-bedded
limestone with some minor interbedding of dolomite. Due to the
extensive faulting and shortening of the St. Paul Group in this
area, it is difficult to distinguish the St. Paul Group aquifer from
the Chambersburg Formation aquifer. Therefore, the St. Paul Group
aquifer can be treated as part of the Chambersburg Formation aquifer
in the K Area. Groundwater yields in this formation are
approximately 15 gpm.
The Pinesburg Station Formation is a light gray dolomite of
Middle Ordovician Age. The dolomites are structureless to locally
planar, laminated, and contain small, white rosette chert nodules
and sparse, dark chert masses. Water flow through the dolomites is
restricted and acts as a barrier to groundwater flow. The contact
between the Pinesburg Station and St. Paul Group carbonates is
enlarged by solutioning and acts as a groundwater conduit along the
barrier. The Pinesburg Station Formation is moderately productive,
with maximum reported groundwater yields of 30 gpm.
The Rockdale Run Formation is an Ordovician Age limestone that
outcrops frequently, forming gently rolling terrain, and is composed
of limestones and a significant number of dolomite beds, both
containing small, white chert nodules. This formation is a highly
productive aquifer, with reported yields up to 410 gpm.
1.3.3 SOILS CHARACTERISTICS
The predominant soils at LEAD are developed through weathering
of the Martinsburg shale and interbedded siltstones. The soils in
the SE Area including the K Area at LEAD have been mapped as part of
the Hagerstown-Duffield Association and Weikert-Berks-Bedington
Association. These soils are described as silty clay loams and
silty clays with shale and limestone fragments (see Figure 1.5).
1.3.4 SURFACE WATER CHARACTERISTICS
Two major stormwater drainage systems serve the SE Area at LEAD.
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SOIL ASSOCIATIONS
laid't-Very stony land-Bucnanan association: Oc*9. -ell dtimcd to
semewnat aoorly drained, nearly level le very steea soils formed m
COIIuviufli 'ram wnaslooe jna Very lieny i*na; en leas ana S'OCS el
mountains
HaierstOwn-Outfield Jiiocunon- Oeeo. well-drained, marly levtl 10
Sleep soils formed m materials weaifiered from limesione; in valleys
Murnll-iaidif association: Oceo. ««tl-arainea, {entiy sloomf 10 mod-
erately ste«o soils formed in colluvium: en mountain (eel slows
Weikert-Bcrks-Bedinf ton association: Shallow to deeo. well-drained.
nearly level to very steeo soils formed m materials weainered 'rom siuu
and inieroedded snai*. sillsione. and sandstone: m valleys
Ockalb-Laidif-Very stony land association; Moderately deeo and deeo.
well-drained, nearly level to very steeo soils formed m colti/vium anil
in materials weathered from sandstone and QiMrlziic. and very stony
land; on loos and sides of i
' mountains
If 74
r*>
Figure 1-5
GENERAL SOILS MAP: FRANKLIN COUNTY,
PENNSYLVANIA
SOURCE: Weston. 1904.
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Letterkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
10
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Drainage from south of Coffey Avenue exits through the storm drain
outfall at the southeastern corner of the SE. It joins other
surface runoff flowing southward 1.5 miles to Conococheague Creek, a
tributary of the Potomac River. A portion of the runoff enters a
small sinkhole located approximately 0.5 miles downstream of LEAD.
Runoff north of Coffey Avenue discharges into the industrial
wastewater treatment plant (IWTP) outfall ditch and into Rowe Run.
Rowe Run flows 3.5 miles to Muddy Run, which enters Conodoguinet
Creek, a tributary of the Susquehanna River. Two springs, Rowe and
Pinola, discharge into Rowe Run 1.25 and 3.1 miles, respectively,
northeast of LEAD. It is believed that these springs are the major
discharge points for groundwater flowing beneath the K Area within
the SE Area.
1.3.5 LAND USES
No national or state forestland, or other public lands were
identified as impacted by the contamination within the K Area at
LEAD. The K Area is not located within a floodplain or wetlands.
The principal land use adjacent to the K Area at LEAD is farming and
raising of livestock (beef cattle and pigs). Principal crops are
fruit trees (e.g. apples, pears, peaches), corn, and potatoes.
No threatened or endangered species have been identified within
the K Area at LEAD. An environmental assessment for LEAD is being
conducted and will result in endangerment and ecological
assessments.
2 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 SITE HISTORY
LEAD is owned and operated by the Army. Although established in
1942 with the mission of ammunition storage, the principal missions
at LEAD currently include overhauling, rebuilding, and testing of
wheeled and tracked vehicles; the issuance and shipment of Class III
chemicals and petroleum; and the storage, maintenance,
demilitarization, and modification of ammunition. Operations
associated with current or prior missions have included cleaning and
stripping, plating, lubrication, demolition, chemical and petroleum
transfer and storage, and washout/deactivation of ammunition. Many
of these activities, except those associated with ammunition, were
qonducted in the SE Area using significant quantities of
trichloroethylene, other chlorinated hydrocarbons, hydrocarbons, and
other solvents.
Past industrial activities and waste disposal practices of
trichloroethylene, hydrocarbons, and other solvents have resulted in
11
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VOC contamination of the soil and groundwater in parts of the SE
Area. The primary contaminant sources in the K Area are the
contaminated soils associated with the various burial trenches,
pits, and landfills formerly used as hazardous waste disposal areas
for the spent solvents such as trichloroethylene and
1,1,1-trichloroethane.
2.2 DESCRIPTION OF INVESTIGATIVE HISTORY
Two areas of LEAD were promulgated to the National Priorities
List (NPL). The two NPL sites at LEAD are the Property Disposal
Office Area (PDO) drainage system and the Southeastern Area (SE)
drainage system. The PDO Area has a Hazardous Ranking System (HRS)
score of 37.51, and the SE Area has a score of 34.21. The SE Area
was listed on the NPL in July 1987, and the PDO Area was listed in
March 1989. These two sites are shown in Figure 2.1. The dashed
lines that separate the areas indicate approximate surface water and
groundwater basins. The K Area is located within the SE drainage
system. Figure 2.2 delineates the source areas of soil .
contamination in the K Area; K-l, K-2, and K-3, which this ROD will
discuss.
A Preliminary Assessment of the depot was conducted by USATHAHA
in 1980. A Remedial Investigation/Feasibility Study (RI/FS) was
initiated by USATHAMA for both NPL Areas in 1984. The nature and
extent of the contaminant sources in the SE Area has been
investigated in these previous reports. See Table 2.1 for a
compilation of all environmental contamination reports for LEAD
which are contained in the administrative record. Groundwater
contamination in the K Area within the SE Area has been confirmed
for four source areas; areas A, B, K-l, and K-2, with three of these
areas; areas A, B, and K-l identified as migration sources
contributing to the groundwater contamination in the area (Weston,
1984). Soil gas sampling performed within the SE Area during the
1989 EPRDA Soil Gas Investigation identified four areas of high
concentrations of VOC's; areas C, K-l, K-2, and K-3 (Weston, 1989a).
Offpost groundwater contamination has occurred in private wells
adjacent to the SE Area at LEAD. Recent efforts with a dye tracer
study have helped to more clearly identify contaminant pathways
between some sources within the SE Area and certain offpost, private
wells.
Pursuant to CERCLA Section 120, an Interagency Agreement (IAG)
was signed in February 1989 between EPA, PADER, and the Army to
ensure cooperation and understanding between all three parties and
to facilitate a sound and aggressive environmental cleanup program
at LEAD for the two NPL areas. The accelerated remedial action for
the K Areas which is the subject of this ROD is required by the IAG.
The regulators have reviewed all prior reports listed in Table 2.L.
12
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SCALE
600 0 600 1.200 FEET
200 0 200 400 METERS
SOUTHEASTERN
AREA
AMMUNITION DISPOSAL AREA
AND AMMUNITION STORAGE AREA
DISPOSAL AREA
&ME6
OASHEO LINES INDICATE APPROXIMATE
SURFACE AND GROUND WATER BASIN BOUNDARIES
PROPERTY DISPOSAL
OFFICE AREA
SOUTHEAST
INDUSTRIA
AREA
ROCKY SPRING
ROCKY SPRING
LAKE
SOURCE: 6SC. 1Mt«.
Figure 2.1
SURFACE WATER AND GROUNDWATER
BASINS AND STUDY AREA AT LEAD
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Leilerkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
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M ««Malt UIJjHUSAL
B CLAY-LINED OIL-BURNING PIT
C LANDFILL
0 IWTP LAGOONS
E OIL-BURNING PIT
F IWTP DITCH SLUDGE BURIAUSPREAL
Q SECURITY LANDFILL
H LANDFILL
I LANDFILL
J LANDFILL
K-1 LAGOON
K-2 PARTIAL REVETMENTS
K-3 REVETMENTS
K-4 LINEAR MAGNETIC ANOMALY
OLD MORTAR ROAD
/ I
SOURCES: Billtll*.
W.non. 19(4.
CSE. 1M(b.
Figure 2.2
POTENTIAL CONTAMINANT SOURCE AREAS
IN THE SE AREA
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Letterkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
14
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Table 2.1
LEAD CERCLA Beports for the PDO/SE Areas
1. Installation Assessment USATHAMA Jan. I960 (USATHAMA, 1980)
2. Arm/ Pollution Abatement Studies (PDO) Berger Associates Feb.
?681 (Berger. 1981)
3. Geophysical Survey of the Southeastern Area (SE) Battelle
June 1983 (Battelle, 1983a)
4. Environmental Contamination Survey (SIA) Battelle Sept.;1983
(Battelle, 1983b)
5. Environmental Contamination Survey (PDO) Battelle Oct. 1983
(Battelle, 1983c)
6. Environmental Contamination Survey: Exploratory and
Confirmatory (PDO & SIA) Battelle Dec. 1983 (Battelle, 1983d)
7. Remedial Investigation/Feasibility Study of LEAD (SIA -
Disposal Area) ESE Feb. 1984 (Weston, 1984)
8. Environmental Contamination Survey: Multiphase (PDO) & SIA)
Battelle May 1984 (ESE, 1984)
9. Environmental Contamination Monitoring (PDO & SIA) ESE Jan.
1986 (ESE, 1986a)
10. Pilot Investigation of LTT of VOCs from Soil (Disposal Area-
SIA) Weston June 1986 (Weston, 1986)
11.. Remedial Investigation of the Disposal Area (SIA) ESE Aug.
1986 (ESE, 1986b)
12. Records Search of the Southeast Industrial Area (SIA) ESE
Oct. 1986 (ESE, 1986c)
13. Fracture Trace Analysis (PDO & SIA) EPA-EPIC 1987 (EPA, 1987)
14. Geophysical Investigation of Eastern Boundary, Vol. I (SIA)
Technos/ESE May 1987 (Technos, 1987a)
15
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15. Geophysical Investigation of the IWTP Area, Vol. II (SIA)
Technos, ESE May 1987 (Technos, 1987b)
16. Remedial Investigation of the PDO Area (PDO) ESE Sept. 1987
(ESE, 1987a)
17. Remedial Investigation of the SE Area (SE) ESE Dec. 1987
(ESE, 1987b)
18. Downhole Geophysical Logging of the SE Boundary (SE)
Technos/ESE Dec. 1987 (Technos, 1987c) ;
19. Endangernent Assessment of the PDO Area (PDO) ESE Feb. 1988
(ESE, 1988a)
20. Feasibility Study of the PDO Area (PDO) ESE Aug. 1988 (ESE,
1988b)
21. Feasibility Study of the SE Area, First operable Unit (SE)
ESE Sept. 1988 (ESE, 1988c)
22. Endangertnent Assessment of the SE Area (SE) ESE Sept. 1988
(ESE, 1988d)
23. Feasibility Study of the SE Area, Second Operable Unit (SE)
ESE May 1989 (ESE, 1989)
24. EPRDA Soil Gas Survey (SE - Disposal Area) Weston Oct. 1989
(Weston 1989a)
25. In-Situ Volatilization Study (SE & PDO) Weston Oct. 1989
(Weston, 1989b)
26. Emissions Treatment Technology Evaluations for the ISV Systems
(PDO & SE) Weston Oct. 1989 (Weston, 1989c)
27. Focused Feasibility Study (PDO & SE) USATHAMA Aug. 1990
(USATHAMA. 1990)
28. Public Involvement and Response Plan (PDO & SE) ESE Feb.
1990 (ESE. 1990a)
16
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29. Site Investigation Technical Plan EA Engineering Apr. 1990
(EA, 1990a)
30. Remedial Investigation/Feasibility Study Work Plan ESE June
1990 (ESE, 1990b)
31. Proposed Plan for the SE Area (FFS) LEAD Sep. 1990
(LEAD, 1990a)
32. Proposed Plart for the PDO Area (FFS) LEAD Sep. 1990
(LEAD, 1990b) " •
17
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and have identified problems and data gaps under the RI/FS program.
LEAD is currently conducting field work to ensure that the final
RI/FS documents are complete and adequate. In addition, the
Industrial Waste Treatment Plant lagoons are being closed in
accordance with the Resource Conservation and Recovery Act.
2.3 CERCLA ACTIVITIES
A Focused Feasibility Study (FFS) was prepared for LEAD to
develop and evaluate alternate remedial responses to uncontrolled
releases of hazardous substances from specified areas within the
depot's two NPL sites, the SE Area and the PDO Area. The FFS is an
accelerated Feasibility Study which focuses specifically on
contaminated soils in the K Area and PDO Area. The purpose of the
FFS is to begin remediation on a known source area while the
remaining final remediation plans are being prepared as further
described in the IAG Section IX.D. The FFS is a required document
under the IAG. Within the SE Area, the FFS has focused on the
contaminant sources in the K Area and has evaluated potential final
remedial measures for the soils in the K Area. This study, in
conjunction with past reports, has indicated that soil remediation
is feasible (Weston, 1984).
The FFS provides the information necessary for identification of
final remedial alternatives at LEAD, in accordance with CERCLA and
the NCP. This cost-effective remedial alternative will effectively
mitigate and minimize threats to and provide adequate protection of
public health and welfare and the environment. Except as provided
in 40 CFR 300.68(i)(5), the selected remedy must attain or exceed
applicable or relevant and appropriate Federal and State public
health and environmental requirements that have been identified for
the specific site. This ROD will focus on the contaminated soils in
the K Area. Figure 2.3 shows the areas which this document will
discuss.
As outlined in the IAG, the Army is the lead agency and EPA and
PADER are the support agencies. As the lead agency, the Army is
required to identify the "preferred alternative" and prepare the ROD
for an NPL site. The Army is issuing this ROD as required by
Sections 120(e)(2) and 117 of CERCLA. This document summarizes
information which can be found in greater detail in the Remedial
Investigation/Feasibility Study (RI/FS) for the SE Area of December
1987 (ESE, 1987b), the FFS of August 1990 (USATHAMA, 1990), the
Proposed Plan for the SE Area of May 1991 (LEAD, 1991) as well as
other documents contained in the administrative record file for this
site.
3 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The FFS and the Proposed Plans for the SE Area and the PDO Area
18
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/ f-1
1 MONITORING WELLS'
61-8
KEY
CONTAMINATED SOURCE
AREAS
EXISTING MONITORING WELLS
Figure 2.3
LOCATION OF SOILS TO BE REMEDIATED AT
'LEAD DA
SOURCES: wtnon. iM4: CSE. nun.
REMEDIAL INVESTIGATION
FEASIBLITY STUDY
Letterkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
19
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at LEAD were released to the public on April 6, 1991. These two
documents were made available to the public in both the
administrative record and an information repository maintained at
the EPA Docket Room in Region III, Philadelphia, Pennsylvania, at
Building 663 at LEAD, and at the Coyle Free Library in Chambersburg,
Pennsylvania. The notice of availability for these two documents
was published in a local Chambersburg newspaper, The Public Opinion,
on April 6, 13, 20 and 27, 1991. A public comment period was held
from April 6, 1991 to May 20, 1991. In addition, a public meeting
was held on Hay 14, 1991. At this meeting, the Army presented an
overview of the proposed plan and the preferred alternative being
proposed as required under CERCLA. Community attendance at the v
public meeting was very low. The Responsiveness Summary of this ROD
provides a discussion of public comments received during the public
comment period. This decision document presents the selected final
remedial action for the K Area at LEAD, chosen in accordance with
CERCLA, and the NCP. The decision for this site is based on the
administrative record.
4 SCOPE AND ROLE
Due to the complexity of the contamination problems at LEAD, the
Army has divided the cleanup work in the PDO and SE Areas into
manageable components called "operable units" (OUs). OUs are
separate response measures which are components of the overall
cleanup at a NPL site. There are five operable units currently
planned for the depot. The OUs at the two NPL sites have been
numbered separately. These OUs are;
SOUTHEASTERN AREA
* Operable Unit l - K Area Contaminated Soils
* Operable Unit 2 - SE Area Source Identification
* Operable Unit 3 - SE Area Contaminated Groundwater
PROPERTY DISPOSAL OFFICE AREA
* Operable Unit 1 - Revetments, Oil Burn Pit Contaminated
Soils
* Operable Unit 2 - PDO Area Contaminated Groundwater
The remedial objective for LEAD is to reduce contamination to
levels that eliminate unacceptable risk to human health and the
environment. The overall strategy for LEAD is to address the
contaminated soils OUs first and the contaminated groundwater OUs in
the future. The contaminated soils OUs are being considered first
because contaminated soils are usually less difficult to clean up
than contaminated groundwater, and the contaminated soils are often
more localized and accessible. Therefore, LEAD is taking immediate
actions on the contaminated soils in the PDO and SE Area as required
20
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to reduce the direct risk to human health and the environment
relatively quickly. These actions will also help avert the
contaminated soils from acting as a continuing source of groundwater
contamination in these areas.
This OU, the first one for the SE Area, addresses the
contaminated soils in the K Area. These soils are one of the
principal threats posed by the site. The K source areas include
K-l, a former lagoon area, and K-3, a revetment used in the past for
drum storage. The area K-2 is contaminated as a result of migration
from contaminants from K-l. Therefore, K-2 will be considered as
part of K-l and will be included in this final remedial action., The
selected remedy satisfies the preference for using treatment as a
principal element of the remediation. This remedy will be
consistent with any future remediation at the site.
5 SUMMARY OF SITE CHARACTERISTICS
5.1 SITE CONTAMINATION AND AFFECTED MEDIA
The contaminated medium in the K Area is the soils. Contaminants
in the soils in this area were previously documented and include a
variety of organic compounds at concentrations up to 7,000,000
micrograms per kilogram (ug/kg). The commonly occurring organic
compounds are xylene, trans-1,2-dichloroethylene, ethylbenzene, and
trichloroethylene. The groundwater in the SE Area is contaminated
with the same organic compounds as the soils from the K Area, with
concentrations in the groundwater occurring at up to 20,000
micrograms per liter (ug/L). The soils in the K Area are also
contaminated with various heavy metals, however, groundwater
contamination with metals is minimal in the SE Area, probably due to
the retentive properties of the clayey soils with respect to metals
(ESE, 1986a, 1986b). The limestone geology in the K Area soils
appears to be naturally stabilizing the metals in this area.
Analysis and disposal of treated soils will be performed in
accordance with Pennsylvania proposed Residual Waste Regulations.
5.2 SOURCES OF CONTAMINATION
The primary contaminant sources in the K Area are the
contaminated soils associated with the various burial trenches,
pits, and landfills formerly used as hazardous waste disposal areas
for the spent solvents such as trichloroethylene and
1,1,1-trichloroethane.
5.3 LOCATION OF CONTAMINATION
There are no structures such as buildings or roadways which
could impede the remedial action of the soils in the K Area. The
impacted area is easily accessible and is located away from the main
21
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industrial buildings on depot.
5.4 POTENTIAL ROUTES OF MIGRATION
Migration of the organic contaminants from the SE Area into and
through the groundwater is still occurring due to the continued
presence of the various source soils in the K Area. A slight trend
toward decreasing contaminant levels in the groundwater with time
may be due to the dilution of existing sources by groundwater
throughflow. Interpretations from the dye tracer study being
conducted in the SE Area indicate flow rates in different parts of
the actively functioning aquifer are highly variable, from 4 to 300
feet per hour. As described earlier, groundwater will be addressed
as operable unit three and is the subject of an ongoing RI/FS.
Offpost, the contaminant transport mechanisms appear to be
related to the fractured karst bedrock environment associated with
Rowe and Pinola Springs to the northeast, both of which discharge
groundwater to the surface water of Rowe Run. The direction and
rate of contaminant migration in the groundwater has not been
quantitatively determined in the SE Area due to the complex nature
of the limestone aquifer, but the general flow direction offpost
appears to be to the northeast, toward Rowe Spring, based on
contaminant distributions in offpost private wells.
Thirty-three residences are located within a 3-square-mile (mi2)
.area adjacent to the K Area with the SE Area at LEAD. Assuming each
'home contains 3.8 people, the population impacted by the
contamination at the K Area is approximately 126 people. A waterline
has been installed to 41 residences located adjacent to the SE Area.
These residences have been affected by the contaminated groundwater
which is migrating off depot from the SE Area. The installation of
'the waterline has eliminated the drinking water threat to these
41 residences.
6 SUMMARY OF SITE RISKS
6.1 EXPOSURE ASSESSMENT
The SE Area Endangerment Assessment (EA).(ESE, 1988d) identified
two compounds, 1,1-dichloroethylene and trichloroethylene, as
critical contaminants in the groundwater offpost of the K Area.
Therefore, the FFS concentrated on these contaminants for
determining the site risks for the contaminated soils in the K Area.
The SE Area EA (ESE, 1988d) evaluated potential health risks for
workers and offpost residents by -activities that would bring them
into contact with contaminated soils in the source areas. Skin
absorption, incidental ingestion of soils, and inhalation of vapors
from contaminated soils were considered to be possible.concurrent
22
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exposures. However, ingestion of contaminated soils and direct skin
contact with such soils were not considered for the K Area because
the contaminants are located in soils well below the ground surface
which limits their exposure through direct contact with the soil.
Access onto the installation is restricted by fences which limits
the potential for exposure for non-LEAD personnel. Inhalation
vapors for offpost receptors and all routes for onpost workers in
the K Area were considered.
6.2 RISK CHARACTERIZATION
The cancer risk for all routes for workers in the K Area was
calculated to be 6.10 x 10-8 which is below EPA's acceptable range
for risk levels. EPA acceptable range for risk levels is 1 x 10-4
to 1 x 10-6, with the target risk level designated as 1 x 10-6. A
cancer risk of 1 x 10-6 means that one additional person out of a
million is at risk of developing cancer as a result of site-related
exposure to a carcinogen over a 70-year lifetime if the site is not
cleaned up. This risk analysis for the area indicates that air
concentrations, as a result of volatilization from the soil, do not
present a health hazard to workers. Health risks to residents
located downwind of the K Area were evaluated at less than 1 x 10-7
(2.13 x 10-8) because of the low levels of volatile organics
detected in the soils in this area.
A hazard index (HI) represents the sum of the ratios of
calculated exposure levels to acceptable exposure concentrations for
all chemicals under consideration. The HI provides a reference
point. When the HI exceeds unity, there may be a concern for a
potential health risk. A hazard index of 2.47 x 10-1 for the
noncarcinogenic compounds in the K Area indicates that a significant
health hazard to workers does not exist. Noncarcinogenic compounds
were also determined to pose a low health risk to offpost receptors
potentially exposed to the inhalation pathway.
6.3 RISK CONCLUSIONS
Federal Applicable or Relevant and Appropriate Requirements
(ARARs) are not available for the SE Area indicator contaminants in
the soil; however, the State ARAR for the indicator contaminants in
soils is that the soils must be cleaned up to the extent necessary
to meet the background groundwater cleanup requirements. The State
ARAR for groundwater is background. A soil cleanup criteria was
developed based on the soil-to-groundwater ratios observed in the SE
Area.
The ratios of soil-to-groundwater concentrations were found to
be 1 for 1,1-dichloroethylene and 45 for trichloroethylene in the SE
Area EA (ESE, 1988a). The federal Maximum Contaminant Level (MCL)
for both organics was considered. The MCL is the maximum
23
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permissible level of a contaminant in water which is delivered to
the free flowing outlet of the ultimate user of a public water
system. The MCL for trichloroethylene, 5 micrograms per liter
(ug/L), is more stringent than the MCL for 1,1-dichloroethylene, 7
ug/L. Therefore, by using the MCL for trichloroethylene, the
acceptable soil concentration developed for the K Area in the FFS is
determined to be 225 ug/kg for this compound (45 x 5 micrograms per
liter). The average concentration of trichloroethylene in the K
Area soils is 4,900 ug/kg (ESE, RI, 1987), which exceeds 225 ug/kg,
the calculated soil criteria. Excavation and cleanup of the soils in
the K Area with concentrations above 225 ug/kg is expected to result
in reduction of contaminant transfer from soil to groundwater to
levels which, in conjunction with other final remedial actions in
the Southeastern Area, will eventually reduce groundwater
concentrations.
Actual or threatened releases of hazardous substances from this
site, if not addressed by the response action selected in this ROD,
may present an imminent and substantial endangerment to the public
health, welfare, or the environment.
7 DESCRIPTION OF ALTERNATIVES
. The FFS for operable unit one screened a number of alternatives
that could potentially achieve the remedial objective of reducing
contamination to levels that eliminate unacceptable risk to human
health and the environment. The final remedial action alternatives
initially considered for the K Area encompassed the following basic
actions:
o No Action
o Containment and a cap
o Thermal treatment
o Innovative technologies
All alternatives were evaluated using the following criteria
derived from CERCLA Section 121:
o Protection of human health and the environment
o Compliance with all Applicable or Relevant and Appropriate
Requirements(ARARs)
o Long-term effectiveness and permanence
o Reduction of waste toxicity, mobility, and volume
24
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o Short-term effectiveness
o Implementability
o Community Acceptance
o State Acceptance
o Cost
As a result of initial screening conducted during the Focused
Feasibility Study, the number of alternatives considered for the
contaminated soils in the K Area were reduced from eleven to five.
The eliminated alternatives and the primary reasons for their
elimination may be found in the FFS. Five alternatives were
selected for further detailed analysis (Table 7.1). The No Action
alternative was retained as a baseline for the final evaluations.
One alternative represents the no-action response, one alternative
is limited action, one alternative is for containment response
action, one alternative is a treatment technique, and one
alternative incorporates an innovative technology. These
alternatives are briefly described in the following sections.
7.1 NO ACTION RESPONSE
Alternative 1A:
No Action - Long-Term Monitoring
Capital Cost: $ 0
Annual Operation and Maintenance (O&M) Costs: $ 9355
Present Worth: $ 143,434
Time to Implement: 0 days
Alternative 1A is a no action alternative utilizing long-term
groundwater monitoring. The "No Action" alternative is required to
be evaluated at every site to establish a baseline for comparison
with other alternatives being considered. This alternative involves
taking no action to remediate contaminated media at operable unit
one. Monitoring wells in the K Area would be sampled and the
contaminant concentrations monitored over time for comparison with
£he health-based criteria developed in the SE Endangerment
Assessment. Long-term groundwater monitoring would be conducted in
compliance with EPA 40 CFR Chapter 264, Standards for the Owners and
Operators of Hazardous Waste Treatment, Storage, and Disposal
Facilities, Subpart F, Part 264.100.
25
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Table 7.1 Summary of Remedial Action Alternatives for DA Soils in the
SB Area at LEAD for Detailed Analysis
Alternative
Technologies Used
LA. No Action
IB. Limited Action
- ZC. Containment
o Long-term groundwater monitoring
only
o Long-term groundwater monitoring
o Institutional and land use controls
o Multimedia cap
3D. Treatment - Thermal
4A. Innovative Technologies
o Excavate and treat onsite using
high-temperature incineration
o Excavate and treat onsite using
low-temperature thermal stripping
Notes DA - Disposal Area
LEAD - Letterkenny Army Depot
SE - Southeastern
Source; ESE, 1986b
26
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Alternative IB:
Limited Action - Long-Term Monitoring
Institutional and Land Use Controls
s
Capital Cost: $ 0
Annual Operation and Maintenance (O&M) Costs: $ 9355
Present Worth: $ 143,434
• if
Time to Implement: 0 days
Alternative IB is a limited action alternative using the
long-term groundwater monitoring described in Alternative 1A coupled
with institutional and land use controls. These controls would
provide a measure of protection for human health and the environment
by restricting the use of the groundwater and the surface water
affected by the contamination resulting from the groundwater
movement through the contaminated soils. Long-term groundwater
monitoring would be conducted in compliance with EPA 40 CFR Chapter
264, Standards for Owners and Operators of Hazardous Waste
Treatment, Storage, and Disposal Facilities, Subpart F, Part
264.100.
7.2 CONTAINMENT RESPONSE
Alternative 2C:
Containment - Multimedia Cap
Capital Cost: $ 104,960
Annual Operation and Maintenance (O&M) Costs: $ 9705
Present Worth: $254,150
Time to Implement: 6 months
Alternative 2C is a multimedia cap designed to prevent the
infiltration of rainfall and storm water into the contaminated
zones. The contaminated soil would be left in place and a cap would
be installed over the entire areas; area K-l is 10,000 ft2 and are
K-3 is 4000 ft2. A multimedia cap would consist of a 2foot clay
liner overlain by a synthetic liner, a 1-foot sand layer for
drainage, and 5 feet of soil cover (Figure 7.1). A separate cap
would be designed for each of the areas, K-l and K3. The caps would
be designed to meet ARARs under the RCRA Landfill Closure
27
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MAXIMUM SIDE SLOPE IS
&&^l";.-(-^^ CLEAN SANO DRAINAGE LAYER
,,VC?;V;a ' jV.v:fe^>^-;^ ••'' - -''f -^ ••-••' •,„ HJl^^-sQ M|_ SyNTM£TC MEMBRANE LINE
.'•'••••*'•• • .-- ;-^:S'^^rf!
COMPACTED aAY LAYER
COMPACTED COMMON FILL
ITAMMATED SOILS
Figure 7.1
TYPICAL CROSS SECTION OF MULTIMEDIA
CAP FOB THE DA AT LEAD
SOUBCE. tSt. l»llt>
REMEDIAL INVESTIGATION
FEASIBLITY STUDY
Lellerkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
00
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regulations in EPA 40 CFR Chapter 264, Standards for Owners and
Operators of Hazardous Waste Treatment, Storage, and Disposal
Facilities, Part 264.310 as well as the Pennsylvania groundwater and
closure regulations outlined in Chapter 75.264.
7.3 THERMAL TREATMENT RESPONSE
Alternative 3D:
Thermal Treatment - High-Temperature Incineration
Capital Cost: $ 4,235,191 ;<.
Annual Operation and Maintenance (O&M) Costs: $0
Present Worth: $ 4,235,191
Time to Implement: 90 days
The objective of this alternative is to excavate soils with
concentrations above 225 ug/kg and provide thermal treatment of the
contaminated soils to the lowest levels possible so that the ash can
be used as clean backfill if there are no detectable levels of
contamination remaining. The unit would consist of a rotary kiln
with a secondary combustion chamber, packed tower, and jet scrubber.
Approximately 8000 yd3 of contaminated soils would be excavated and
incinerated onsite with this mobile unit (Area K-l: 10,000 ft2 x 18
ft deep; Area K-3: 4000 ft2 x 8 ft deep). Incineration rates would
be maintained to ensure destruction efficiencies greater than 99.99
percent and to comply with particulate standards and VOC emissions
guidelines. The ash resulting from the incineration would be used
as backfill in the K-l and K-3 areas. Due to the anticipated volume
reduction of the soil from the incineration process, additional
soils would be needed to complete the backfilling of the excavated
areas. ARARs for this alternative include: Pennsylvania Title 25;
Chapters 75 (Solid Waste Management Facilities Applying for a Permit
and Incinerators), 271 (Municipal Waste Management), 273 (Municipal
Waste Landfills), 123 (EPA PM-10 Standards), 127 (Construction,
Modification, Reactivation, and Operation of Sources), 131 (Ambient
Air Quality Standards), the PADER Air Toxic Guidelines, EPA 40 CFR
Chapters 264 and 261, and technical guidelines for incinerators.
7.4 INNOVATIVE TECHNOLOGY RESPONSE
Alternative 4A:
Innovative Technologies - Low-Temperature Thermal Treatment
Capital Cost: $ 1,539,191
29
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Annual Operation and Maintenance (O&M) Costs: $0
Present Worth: $ 1,539,191
Time to Implement: 70 days
The objective of this alternative is to reduce soil contaminant
concentrations below the cleanup criteria of 225 ug/kg without
posing additional risks as a result of air emissions. This
alternative will excavate soils with concentrations above 225 ug/kg
and provide thermal treatment of the contaminated soils to the
lowest levels possible so that the ash can be used as clean backfill
if there are no detectable levels of contamination remaining. A
low-temperature thermal unit evaporates VOCs through the application
of the contaminated soils to an indirect heat exchanger. This unit
operates at temperatures up to 450oF to dry and heat the soils.
Anticipated efficiency of this treatment technique is greater than
99.95 percent. The vaporized contaminants can either be destroyed
through a secondary high-temperature combustor or collected through
condensate or adsorption onto activated carbon (Figure 7.2). If
activated carbon is utilized for emissions treatment, this carbon
would be disposed of in accordance with RCRA regulations.
Approximately 8000 yd3 of soil would be excavated and treated onsite
with this mobile unit. Once treated, the soils could be returned to
the original excavation. ARARs for this alternative include:
Pennsylvania Title 25; Chapters 75 (Solid Waste Management
Facilities Applying for a Permit and Incinerators), 271 (Municipal
Waste Management), 273 (Municipal Waste Landfills), 123 (EPA PM-10
Standards), 127 (Construction, Modification, Reactivation, and
Operation of Sources), 131 (Ambient Air Quality Standards), the
PADER Air Toxic Guidelines, EPA 40 CFR Chapters 264 and 261, and
technical guidelines for incinerators. The Pennsylvania proposed
Residual Waste Regulations, PA Bulletin Volume 20, Number 8,
February 24, 1990, will govern handling and final disposition of the
treated waste. In addition, the site will be capped in accordance
with the PA Residual Waste Regulations.
8 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
CERCLA and the NCP dictate the use of the set of nine criteria
to evaluate remedial action alternatives for a NPL site (Table 8.1).
In this section, the evaluation criteria are briefly described and
all five alternatives are compared to these criteria.
8.1 EVALUATION CRITERIA
These nine evaluation criteria are:
Threshold Criteria:
30
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OlSCHARCC
COMPRESSOR CONVCTQR
__
BRCAK THROUGH
oertcroR
Figure 7.2
PROCESS SCHEMATIC FOR THE MOBILE
LOW TEMPERATURE THERMAL TREATMENT
SYSTEM
SOURCE: Wtmlon. ISif.
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Lellerkenny Army Depot
U.S. Army
Toxic and Hazardous Materials Agenc
Aberdeen Proving Ground, Maryland
-------
Overall Protection of Hunan Health and the Environment addresses
whether or not a remedy provides adequate protection and describes
how risks posed through each pathway are eliminated, reduced, or
controlled through treatment, engineering controls, or institutional
controls.
s
Compliance with ARARs addresses whether or not a remedy will
meet all of the applicable or relevant and appropriate requirements
of Federal and State environmental statutes and/or provide grounds
for invoking a waiver.
Balancing Criteria: - -f
Long-Term Effectiveness and Permanence refers to the magnitude
of residual risk and the ability of a remedy to maintain reliable
protection of human health and the environment over time once
cleanup goals have been met.
Reduction of Toxicity, Mobility, or Volume (TMV) Through
Treatment is the anticipated performance of a treatment technology
that may be employed in a remedy.
Short-Term Effectiveness refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to
create adverse impacts on human health and the environment that may
result during the construction and implementation period.
Implementability is the technical and administrative feasibility
of a remedy, including the availability of materials and services
needed to implement the chosen solution.
Cost includes capital, operation and maintenance costs, and
present worth. An operating period of 30 years was selected to
allow for comparison of alternatives.
Modifying Criteria:
State Acceptance indicates whether, based on its review of the
FFS and the Proposed Plan for this operable unit, the State concurs
with, opposes, or has no comment on the preferred alternative.
Community Acceptance is assessed in the Record of Decision for
this operable unit following a review of the public
comments received on the FFS and the Proposed Plan.
8.2 ANALYSIS OF ALTERNATIVES
Overall Protection of Human Health and the Environment.
Alternatives 1A and IB do not reduce contaminant concentrations in
the groundwater, although IB would provide information.on migration
32
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of contaminants and the potential threat to receptors. Alternative
2C would reduce the amount of infiltration into the contaminated
soils which would potentially reduce the concentration and migration
of contaminants. However, the level to which this alternative would
reduce the groundwater concentrations is unknown. Alternatives 3D
and 4A would both result in a reduction of VOC concentrations in the
soils, with a resulting reduction in the groundwater concentrations.
Compliance with ARARs. Alternatives 1A and IB would not achieve
the ARARs for the contaminated soils based on the groundwater
concentrations in the areas and the level of cleanup required for
soil cleanup. Alternative 2C would not achieve soil cleanup ARARs
for the source areas and this alternative would require additional
testing to determine if it would reduce contaminant concentrations
in the groundwater to acceptable chemical-specific ARARs.
Alternatives 3D and 4A would be expected to result in achievement of
soil ARARs for the source areas and therefore reduce the groundwater
concentrations below the chemical-specific ARARs. Alternatives 3D
and 4A would also comply with the necessary action-specific ARARs.
Long-Term Effectiveness and Permanence. With Alternative 2C,
the long-term effectiveness of the cap to control the source is
undetermined and the effect on the groundwater is also undetermined.
By removing the contaminants from the soils, Alternatives 3D and 4A
are highly effective in the long-term. These alternatives would
necessitate excavation of the soils before the treatment could begin
so that the performance of the treatment could be more easily
monitored.
Reduction of Toxicity, Mobility, or Volume (TMV) Through
Treatment. Alternative 2C would theoretically reduce the mobility
of the contaminant by reducing the infiltration however, the level
of mobility reduction is unknown. This alternative would not reduce
the toxicity or the volume of the source. Alternatives 3D and 4A
would both provide for substantial reduction in TMV of the
contaminant in the soil using high-temperature incineration (3D) or
low-temperature thermal treatment (4A) to achieve actual destruction
of the contaminants.
Short-Term Effectiveness. In Alternative 2C, the installation
of a cap would have an undetermined effect on the migration of
contaminants, therefore the short-term effectiveness of this
alternative is unknown. Alternatives 3D and 4A are both fairly
effective in'the short term. However, 4A would take the least time
£o implement which would result in greater short-term effectiveness.
Implementability. All alternatives utilize known technologies
for which the necessary equipment and expertise is readily
available. Therefore, no implementation problems are anticipated
for any of the alternatives.
33
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Cost. Alternative 2C has low capital, operation and maintenance
(O&M) costs, and present worth costs. However, this alternative does
not satisfy the other eight criteria. Alternatives 3D and 4A both
fulfill the other criteria with 4A having lower capital and present
worth costs ($1,539,191) than 3D ($4,235,191). Both 3D and 4A have
no O&M costs associated with their implementation.
State Acceptance. State and federal acceptance of the preferred
alternative was evaluated after PADER and EPA had reviewed and
approved the Proposed Plan for the SE Area.
Community Acceptance. Community acceptance of the preferred
alternative was evaluated after the public comment period on the
Proposed Plan for the SE Area. The community acceptance is
described in the Responsiveness Summary of this ROD.
Table 8.1 is a summary of the detailed analysis for the five
alternatives which were considered for the contaminated soils in the
K Area.
9 SELECTED REMEDY
The preferred alternative for OU1 is Alternative 4A, Innovative
Technology. This alternative includes excavation and
low-temperature thermal treatment of the contaminated soils. Based
on current information, this remedial approach would appear to
provide the best balance in meeting the nine evaluation criteria.
9.1 RATIONALE FOR SELECTION OF PREFERRED ALTERNATIVE
The final remedial action recommended for the contaminated soils
in the K Area at LEAD is Alternative 4A, excavation and
low-temperature thermal treatment of these soils. The selected
remedy is comprised of:
a. Excavation of 8000 yd3 of contaminated soils according to
the procedures outlined previously,
b. Thermal treatment of the contaminated soils at a temperature
not to exceed 450°F,
c. Destruction of the volatilized contaminants by a secondary
high-temperature combustor,
d. Chemical analysis of representative samples of the treated
soils to ensure cleanup criteria are met,
e. Proper management of treated soils.
34
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U)
U1
1
TABLE 8 1 *••«"> "f 0»'all«l Ainlysls uf 1
1 SIMM. I/I
it;
(.mlnlif, Allenaitvra Im IW Nulls . • ' . /
Kf'li Iniiilr*! AifmiMil for TrrJinlnQr, 0 9,355 1^
mtctlon arliluvD with exjnsun to Hal Oil tan; ls|>li ff*il|nmt.
In soils or nncillAl arttai ff<»»ikaur will fasy'to mty raslly lie ajnrarnn.
(lUiiWMer objectlvtis iX 1* iwited Infilmnic dMnliKd; ««l iqiere
aral •nhiuiln louovor. .. parrs are
rramnlty ml rrwllly
* - a|jpncy ctsiporc avnl iMile
my In
difficult to
vlKaln since It
protwt lum
Ho Will int Risk Associated Not reliable Nu technical An>rov«l for Tedmlogy. 0 9,355 "
nrtctlun achlffva with exrosure to llnltetlons; lapleoenutlon ei>il|nent.
In soils or rardlal action gruukoter will easy to any easily be opnrators.
g/tinkMer objectives rot be redced i laplaanit obtalnBd; Mil spare
and aulittJilfi luuever. ' pnrts are
• amenity ail readily
agnry amnct available
any In
dlfflcuk to
obtain since 1C
ihes IDC
protect liuai
liralrli
-------
K--Cint*l,
HiltlBBriU cap
Level of
protection U
urie centred;
pllot-or born.
scale test
rwfUrcd to
detenaliie level
ot protection
UtnoM
If U
will
•Mt
ARM
I Will rertc.
•obi dry;
Will lot
rwkce
linlclly or
vnliiae
Leach teal a
required to
deteraiiia level
of |>crffinmce
lead, test •«!
-xkllrei
roifilred to
*i»n»im If
risk la re«i«-ed
Kelld>U
JO"
ON
OtalU hle)|.
trafierecure
Incineration
Piwldee
protection
of source end
destruction of
contaminants
0»- Will reduce Achieves all
Pile. 1HV ^,^4
respnoe
objectives
Risk associated
with troundMter
"oposure will be
ellalnaud
Ccenttr
(tegnw of
difficulty
o\» to
cunstnc-
for
l»|>la«nitM:lun
any easily be
(Stalled;
equlpnnic,
ojmrntora.
104,9609,705254 50
Icwnvnr, U
U au.ll.
<•«! wldoly
used
tedinlngy
H»
niUtloial
any be
to dnuutrate
level of
protection to
o)*aln
cnauilty aid
*tf**V support
pnns are
•vcllable
Tecriologx,
«Hp»eiit.
operators.
Italtatlone; ^uj, lt-u
hm*"r- "gency for air
pereonal eedulon.
sr"" s
excavatlun-
4,235,191 0 4,335,1'
08
go 30
oo
Provtdn
protection
l'iru<0> rmoviil
of murce arel
dulnctlm of
conrjuJnenta
piles
Will rert«
1MV
Adiiewa all
raaedlal
respraew
Risk associated Reliable
will be
•I lniiiatoJ
operation
H> tmiidcal
IMraClara;
hrnwver.
prorecrlw
«MT eay be
required
<**!'«
excavatlan-
opererlan
Coordination
vlrt, ,ute
«e«cy for air
•-""la's
"quired
1.539,191
0 1,539,19
o|*rMors
readily
evnllable
-------
Figure 9.1 presents a diagram of the treatment system. The
soils would be staged in an area adjacent to the treatment unit and
would require approximately 2 acres.
Low-temperature thermal treatment of the contaminated soils
would result insthe achievement of the ARARs for the soils and
ultimately for the groundwater in the K Area. The technology has
been tested in the field and has proven successful in lowering
contaminant concentrations in soils below ARAR levels. Also, the
utilization of this alternative would meet the ARARs which were
discussed during the description of the alternative. However,
coordination with PADER would be necessary for the air emissions.
This alternative is cost effective in that it is expected to meet
the ARAR and response objectives for a comparable or lower present
worth cost than most of the other treatment alternatives, and this
alternative satisfies all other evaluation criteria. There are no
O&M costs associated with this alternative and the present worth of
this treatment ($1,539,191) is lower than alternative 3D, high
temperature incineration, which is the only other acceptable
alternative.
10 STATUTORY FINDINGS
Because this action is a final remedial action, it is necessary
to achieve all requirements that would apply to a final action under
CERCLA. The Army plans to remediate the contaminated soils in the K
Area to cleanup levels that would eliminate the need for any further
action with regards to the soils in this area. This action provides
for the reduction and minimization of contaminant migration by
treating the soils and thereby controlling the sources in the K
Area.
10.1 PROTECTION OF HUMAN HEALTH AND ENVIRONMENT
As required by Section 121 of CERCLA, alternative 4A provides
for the protection of human health and the environment by lowering
the contaminant concentration in the soils and ultimately in the
groundwater. The TMV of the contaminants in the soils and
groundwater would be permanently and significantly reduced as a
result of the implementation of this technology. This alternative
would also be effective in the short-term as this method of
treatment takes the least amount of time to implement. Although the
exposure levels for this site are already within the EPA accepted
range of 1 x 10 -4 to 1 x 10 -6 for risk, this treatment would
reduce the exposure levels even further.
10.2 Compliance with ARARs
ARARs are provided to the Army by PADER and EPA Region III for
37
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00
-u
08
go so
OO
SCREEN
DISCHARGE
COMPRESSOR f CONVCtR
il CAR80M , ^ ,,,
sf
flRCAKIMROUCH
Figure 9.1
PROCESS SCHEMATIC FOR THE MOBILE
LOW TEMPERATURE THERMAL TREATMENT
SYSTEM
SOURCE: Wctlon. 1017.
REMEDIAL INVESTIGATION/
FEASIBILITY STUDY
Lellerfccnny Army Dcpol
U.S. Army
Toxic and Hazardous Materials Agency
Aberdeen Proving Ground, Maryland
-------
the soil and air emissions from the low-temperature thermal
treatment unit. The air emissions from this treatment will be
controlled by either a secondary high-temperature combustor or
activated carbon so that attainment with applicable Federal and
state air regulations will be achieved. The generation of any
wastes from the implementation of this alternative will also be
managed according to applicable Federal and state regulations.
Federal ARARs are not available for the indicator contaminants in
the soil; however, the State ARAR for the indicator contaminants in
soils is that the soils must be cleaned up to the extent necessary
to meet the groundwater cleanup. The state ARAR for groundwater is
background. Therefore, the source soils in the K Area must be ..
remediated to levels which will provide that the Pennsylvania
groundwater ARARs are met. Selection of this action does not
expressly or otherwise waive the Pennsylvania ARAR for groundwater
which requires that groundwater be remediated to background levels.
Evaluation of the risks to and posed by the groundwater is ongoing
and will be addressed in Operable Unit 3.
Because this action is being performed under CERCLA, formal
permits for discharges to air and operation of a waste treatment
facility are not required. However, PADER and EPA technical
requirements for these permits will be established and met during
the performance of this final remedial action.
10.3 COST-EFFECTIVENESS
This action has been determined to be cost-effective in that it
achieves the remedial action objectives and meets the best balance
of the evaluation criteria at the least cost.
10.4 UTILIZATION OF PERMANENT SOLUTIONS
This alternative achieves a long-term permanent solution and
utilizes an innpvative treatment technology to the maximum extent
possible. In addition, the planned final remedial action satifies
the statutory preference for employing treatment which will
significantly reduce the mobility, toxicity, and volume of
contaminated soil. Approximately, 8,000 yd3 will be excavated,
treated, and returned to the site. Removal efficiencies of
approximately 97.00 percent to 99.95 percent are expected for this
planned final remedial action. This treatment method uses a known
technology for which the equipment and expertise is readily
available, and this technology is cost-effective.
The removal of the contaminants will be realized with this
planned final remedial action. This alternative will reduce the
risks associated with the groundwater exposure since this method
will destroy nearly all of the VOC contaminants in the soil.
Therefore, the short-term and longterm effectiveness of the
39
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treatment is realized.
The short-term effectiveness and the reduction of the TMV were
regarded as the most decisive factors in the selection process.
This action is a final ROD action for the contaminated soils in
the K Area as it is a permanent solution. Implementation of this
alternative will contribute to the overall final remedial action in
the SE Area which will be concerned with the contaminated
groundwater in this area. Low-temperature thermal treatment meets
the statutory requirement to utilize permanent solutions and
treatment technologies to the maximum extent practicable.
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3. RESPONSIVENESS SUMMARY
This Responsiveness Summary documents concerns and
comments regarding proposed remedial actions for K-Area Operable
Unit One as expressed to the United States Department of Army by
members of the community surrounding the site. The remarks were
presented during the public comment period, and they addressed the
Army's FFS and Proposed Plan to remediate contaminated soils at
the K-Area of the Letterkenny Army Depot.
a. Summary Community Involvement
Community relations activities at LEAD to date have *
included review and coordination meetings with federal and state
regulatory agency personnel; site visits and/or meetings with
elected federal, state and local officials; news releases to the
local media; and direct contact with nearby property owners
through the offsite well sampling program and subsequent
bottled-water provisions and connection to the Guilford Water
Authority (GWA).
Meetings with regulatory agency personnel have been
conducted regularly and are held with representatives from LEAD,
USATHAMA, the Pennsylvania Department of Environmental Resources
.(PADER), EPA Region III, Department of the Army, U.S. Army
Materiel Command (AMC), and Depot Systems Command (DESCOM).
Topics of discussion at these meetings generally included review
of project status, review of new technical information, resolution
of problem areas, and direction and schedule for further studies.
In addition to the formal meetings, LEAD, USATHAMA, PADER, and EPA
personnel maintain frequent telephone contact on an as-needed
basis.
Site visits to LEAD have been made by representatives of
USATHAMA, PADER, EPA Region III, and USATHAMA contractors.
Numerous site visits by PADER representatives have allowed
consistent communications and cooperation between LEAD and PADER.
Formal and informal project briefings and/or site visits have also
been held with local and township officials and state
representatives and senators.
At various times since June 1982, formal news releases
have been issued by LEAD concerning the groundwater contamination
problem. The timing of these releases has generally coincided
with the availability of significant results from the onpost and
offpost contamination surveys and with the occurrence of status
review meetings between LEAD, USATHAMA, EPA and PADER. The news
releases have provided the local media and general public with
information on the status and results of the contamination
surveys, ongoing actions to protect public health, and plans and
schedules for additional activities.
41
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Numerous articles have been published in local and
regional newspapers concerning the contamination problem at LEAD
since the problem was first identified in mid-1982. Topics
covered in the articles has ranged from informational reports on
the results of the technical environmental surveys to interviews
with affected presidents and their concerns on the problem.
Public involvement activities regarding the LEAD
contamination problem also have involved direct contact and
communication with local property owners, businesses, churches and
residents. LEAD held four local news conferences in 1982 to
directly brief local citizens, media and officials regarding the
contamination problem. A news conference was also held at LEAD in
August 1985 in conjunction with the pilot thermal stripping
project. The technology presented during that news conference is
the forerunner to the technology being proposed for remediation of
the K Area soils. Contact with the local citizens also has been
made in conjunction with the offsite well sampling program, which
was initiated in certain adjacent areas in mid-1982. Local
residents who have been affected by contamination of their potable
wells have had contact and communication with LEAD through the
Army's program to provide bottled water and, ultimately,
connection to GWA. These contacts have included letters to and
meetings with residents with affected potable wells.
Since the groundwater contamination problem at LEAD was
identified in mid-1982, overall public interest and concern with
the problem has been relatively high. Identified community
interest and concern with the problem has involved primarily
citizens residing in the potentially affected areas adjacent to
LEAD and the local Chambersburg area. Interest in the
contamination problem at LEAD outside the local area primarily
involves EPA Region III and PADER as part of their regulatory
programs, and state and federal elected officials representing the
local citizens.
Currently, the primary community concerns identified at
LEAD pertain to the contamination of groundwater and the safety of
drinking water. Local concerns with the contamination problem
have been significant since contamination levels in some offpost
drinking water wells were found at higher levels than the
recommended human health criteria. The local residents affected
by the groundwater contamination are satisfied since they are now
connected to GWA. However, many residents interviewed indicated
^displeasure with the length of time it took the Army to provide
./'them with clean water.
More than 9 years have passed since the problem was
initially identified, and, as may be expected, a number of
community concerns have been expressed in association .with the
groundwater contamination problem. These concerns include the
following:
42
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o Desire to know if well water will be safe to use again
in the future;
o Potential long-tern health effects that may have
occurred prior to knowing about the problem;
o Concern about fairness in water bill settlements;
o Concern regarding amount of money spent on research
and studies instead of corrective actions;
o Concern that contamination will continue to spread;
o Schedule or expediency of efforts to remedy problem;
o Effectiveness of remedial actions; and
o Devaluation of property.
•-ir
The Army, through public meeting, news conferences and
news releases, has provided the local community with all available
information to address the concerns raised over the contamination
problem. The Technical Review Committee (TRC) established in
conjunction with the LEAD installation restoration program
includes representatives of the city of Chambersburg, Greene
Township, Franklin County, and Southampton County. The TRC was
established to provide a forum to address public concerns and
questions and to keep the public informed of installation
restoration activities at LEAD.
c. Summary of Public Comments and Responses
No written comments were received during the public
comment period for the Proposed Plan. The comment period was held
from April 6, 1991 through Hay 20, 1991. Also, there was only
limited participation at the public meeting held on May 14, 1991
to discuss the Proposed Plan. No specific comments or concerns
were raised at the public meeting dealing specifically with the
Proposed Plan for the PDO Area Source Areas. Two main comments
raised during the meeting are summarized below along with
discussion that followed:
1. One citizen was concerned about the overall higher
rate of cancer for residents within the area surrounding
Chambersburg and inquired if the contamination problems at LEAD
could be the cause.
Response: While this was outside the scope of the
Proposed Plan in question, the Army provided a brief explanation
of the risk factors associated with the contamination at the K
Areas and the PDO Area source areas and available pathways from
the site to offpost residents. The low contamination levels,
coupled with the limited pathways to the offpost residents makes
it unlikely that any such increase in cancer could be linked to
the environmental problems at LEAD.
2. Another citizen raised a concern over the metals
43
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contamination in the soils and the absence of a plan for treatment
of the metals in the Proposed Plan.
Reponse: Army representatives explained that the metals
contamination in the soils have been stabilized by the clayey
soils. Metals have not been detected in the groundwater at the
site and are, therefore, not considered a threat to the
environment. It was further explained that the treated soils will
be analyzed to determine if thermal treatment effects the ability
of the clayey soils to stabilize the metals, thereby creating a
potential leaching problem, prior to placement of the soils into
the excavations.
r
d. Remaining Concerns
All concerns raised during the public meeting were
addressed to the satisfaction of all in attendance.
44
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