United States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
EPA/ROD/R03-93/175
September 1993
PB94-963905
&EPA Superfund
Record of Decision
USN Naval Air Development
Center (Operable Unit 1), PA
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT Mtt
EPA/ROD/R03-93/175
No.
4. TO* and Subtftta
SUPERFUND RECORD OF DECISION
USN Naval Air Development Center (Operable Unit 1), PA
Second Remedial Action
& Rape* Data
09/29/93
7. Authorfc)
& PatfcjHiUnj Orpanfratlon Rapt. No.
ft Pwtermlng Organization Nun* and Addraa*
to Preset Task/Work Ui* No.
11. ContracKC)orGrant(G)No.
(C)
(G)
12 Sponaoring Organization Nanw and Addran
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Typ* of Report* Period Covarad
800/800
1& Supplementary Not**
PB94-963905
ia Abatract (Limit 200 words)
The 734-acre USN Naval Air Development Center (Operable Unit 1) site is a Naval
facility located in Warminster and Iryland, Bucks County, Pennsylvania. Land use in
the area is predominantly commercial, industrial, recreational, and residential, with
areas of open land, woodlands, and wetlands habitats within and near the site. In
addition, the site lies in an upland area between two local drainage basins. The
northern 65 percent of the site drains to the north towards Little Neshaminy Creek.
The southern 35 percent of the site drains to the south towards the headwaters of
Southampton Creek, a tributary of Pennypack Creek. These streams are used for
recreational and industrial purposes. The estimated 2,000 people who work onsite use
the ground water to obtain their drinking water supply and for industrial and
commercial uses. In 1944, the site was commissioned mainly for research/ development/
testing, and evaluation of Naval aircraft systems. Historically, wastes containing
hazardous substances have been generated during aircraft maintenance and repair, pest
control, fire-fighting training, machine and plating shop operations, spray painting,
and various materials research and testing activities in onsite laboratories. From 1940
to 1980, the wastes, including paints, solvents, sludges, and waste oils, were disposed
of in onsite pits, trenches, and landfills. In addition, wastes were burned in a fire
(See Attached Page)
17.
Document Analytic i
Record of Decision - USN Naval Air Development Center (Operable Unit I)/ PA
Second Remedial Action
Contaminated Medium: gw
Key Contaminants: VOCs (PCE, TCE), metals (arsenic)
COSATI FMdGraup
AvaflabUtty Statement
•M. Security Class (TWa Raped)
None
20. Security CUs«(Thl« Pag*)
None
21. NaofPagM
58
22. Price
(SMANSU39.lt)
See Instruction* an Aewara*
OPTIONAL FORM Z7Z (4-77)
(Formerly HTIS-M)
Department of Commerce
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EPA/ROD/ROX-93/175
USN Naval Air Development Center (Operable Unit 1), PA
Second Remedial Action
Abstract (Continued)
training area until 1988. These disposal activities resulted in the release of hazardous
substances to the environment. To date, eight areas, numbered one through eight, have
been identified as areas used for the disposal of wastes containing hazardous substances.
None of these areas are currently .active. For investigative purposes, sites 1, 2, and 3
have been grouped into area A, while sites 5, 6, and 7 have been grouped into area B.
Prior to 1985, EPA conducted two preliminary onsite investigations. Beginning in 1988,
the Navy conducted detailed investigations of the site, which indicated that ground water
underlying at the site was impacted by the past disposal activities. In 1990, the Navy
and EPA signed an IAG to establish a procedural framework for developing and implementing
onsite investigative and response actions. In 1993, in response to the detection of
contamination offsite, the Navy installed water treatment systems in each affected
residence. For remediation purposes, the site has been divided into two OUs. This ROD
addresses contaminated ground water attributable to areas A and B in overburden and
shallow bedrock as an interim remedial action to prevent further migration of contaminated
ground water, as OU1. Future RODs will present the final selected remedy for OU1 and will
address ground water remedies for contamination in overburden and shallow bedrock in other
areas and ground water deep bedrock, waste, soil, surface water, and sediment, as
necessary. The primary contaminants of concern affecting the ground water are VOCs,
including PCE, TCE, and carbon tetracloride; and metals, including arsenic.
The selected interim remedial action for this site includes installing ground water
extraction wells and pumping ground water to hydraulically control migration of
contaminated ground water; treating extracted ground water using air stripping, carbon
adsorption, precipitation, sedimentation, and filtration; providing for the potential use
of another treatment technology, such as ultraviolet oxidation, if the treatability study
indicates that the selected remedy is ineffective for the removal of contaminants;
sampling treated water periodically to determine the effectiveness of the treatment
system; discharging treated water to an unnamed tributary of either Little Neshaminy Creek
or Southampton Creek; installing and operating a vapor phase carbon adsorption unit, as
necessary, to remove VOCs from the air stripper emissions; treating or disposing of solid
residuals offsite; monitoring ground water in onsite monitoring and residential wells;
evaluating, periodically, the hydrogeologic data and the effectiveness of the extraction
system in minimizing contaminated ground water migration; and modifying the system, as
necessary, based on the periodic evaluations. The estimated present worth cost for this
remedial action is $13,172,000, which includes an annual O&M cost of $628,000.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific cleanup standards for this interim remedial action were not provided
because the goal of the remedy is to limit migration. Treated ground water will meet the
effluent limits developed in accordance with the CWA and the State NPDES requirements.
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RECORD OF DECSKJN
NAVAL MR DEVELOPMENT CENTER
DECLARATION
SHE NAME AND LOCATION
Naval Air Development Center
Warminster Township
Bucks County, Pennsylvania
STATEMENT OF BASIS AND PURPOSE
This Record of Decision (ROD) presents a selected interim remedial action for Operable Unit One
(OU-1) at the Naval Air Development Center in Warminster Township, Bucks County, Pennsylvania (the
•Site1), chosen in accordance with the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) of 1980, as amended, 42 U.S.C. § 9601 et sea and, to the extent practicable.
the National Ol and Hazardous Substances Poflution Contingency Plan (NCP), 40 C.F.R. Part 300.
This decision is based on the Administrative Record for this Site. In January 1993, the facility was
renamed Naval Air Warfare Center (NAWQ Aircraft Division Warminster.
The Commonweaith of Pennsylvania concurs with the selected interim remedy for OU-1 at this Site.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this Ste, if not addressed by
implementing the interim response action selected in this ROD, may present an imminent and
substantial endangerment to public health, or welfare, or the environment
OF THE SELECTED
The selected interim remedy for OU-1 is the first remedial action addressing the Site. OU-1 consists of
contaminated groundwater attributable to Area A and Area B at the Sto in overburden and shallow
bedrock aquifers. The objective of the selected Interim remedy is to minimize the migration of the
contaminated groundwater. A final remedial action for OU-1 wi be selected in a final Record of
Decision for OU-1 to be issued after the ful nature and extent of contaminated groundwater
attributable to Area A and Area Bin overburden and shaJtow bedrock aqutfers are identified The
aotoction of the final remedial action wl consider the information generated during the implementation
of the interim remedal action. Future actions at the Sto wl address groundwater in overburden and
shaflow bedrock in other areas, groundwater in deep bedrock, waste, soOs, surface water, and
sedhnent as necessary.
The aotoctod Interim remedy for OU-1 includes the following major components:
• InstaBatton, operation and maintenance of groundwater extraction weds
• Installation, operation and maintenance of an onsite groundwater treatment system which includes
precipitation, fttration, air stripping and carbon adsorption, and/or other necessary means of
• Periodic sampling of treated water to ensure the effectiveness of the treatment system
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• Discharge of treated water to an unnamed tributary of Unto Neehaminy Creek or an unnamed
tributary of Southampton Creek
• Installation, operation and maintenance of vapor phase carbon adsorption units as necessary
• Offsfte treatment and/or disposal of solid residuals generated during water treatment
• Monitoring of groundwater in monitoring wells and residential wells
• Installation and periodic sampling of observation wells to ensure the effectiveness of the
groundwater extraction wells
• Periodic evaluation of hydrogeotogic data and the effectiveness of the groundwater extraction
wells
• Modification of the groundwater extraction well system and/or groundwater treatment system
as necessary based on periodic evaluations
STATUTORY DETERMMATONS
Pursuant to duly delegated authority, we hereby determine, pursuant to Section 106 of CERCIA 42
U.S.C. I 9606 that this interim action to protective of human health and the environment, complies with
Federal and State applicable or relevant and appropriate requirements directly associated with this
action, and is cost-effective. Athough this action is not intended to fufly address the statutory
mandate for permanence and treatment to the maximum extent practicable, this interim action utfltzes
treaurtent and thus is in furtherance of that statutory mandate. Because this action does not
constitute the final remedy for Operable Unft One, the statutory preference for remedies that employ
treatment that reduces toxjcty, modtty, or volume as a principal element. aRhough partiaty addressed
by this remedy, wsl be addressed by the final response action. Subsequent actions are planned to.
address fufly the thie^ts posod by the conditions at the SKsi
Because the interim remedy addressing groundwater is Bcely to resufc in hajamVim substances
remaining onsite above heath-based levels, a review wi be conducted wthJn five years of the
remedial action to ensure that tire remedy continues to provide aotoquate protection of human health
and the environment Because this to an interim action ROD. review of this Ska and of trUsremeoywel
be continuing at the Navy and EPA continue to develop final remeoTal atemativw for Operable Unt
One.
WHam L MeCrackan
Captain, U.a Navy
CornrnanoTng OBear
Naval Air Warfare Center. Warmfcmar
Stantoy L LaskowskJ . Data
/relating Regional Administrator
' EPA Region Ifl
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RECORD OF DECISION
TABLE OF CONTENTS
SECTION PAGE
I. SITE NAME, DESCRIPTION, AND LOCATION 1
II. SITE HISTORY 1
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION 7
IV. . SCOPE AND ROLE OF THIS RESPONSE ACTION 8
V. SUMMARY OF SITE CHARACTERISTICS AND EXTENT OF CONTAMINATION 8
VI. SUMMARY OF SITE RISKS 26
VII. DESCRIPTION OF ALTERNATIVES 38
VIII. COMPARATIVE ANALYSIS OF ALTERNATIVES 40
IX. SELECTED REMEDY 42
X. STATUTORY DETERMINATIONS 45
XI. DOCUMENTATION OF SIGNIFICANT CHANGES 48
XII. RESPONSIVENESS SUMMARY 48
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FIGURES
NUMBER PAGE
1 NAWC Wanninster Site Location Map 2
2 NAWC Wanninster Waste Disposal Locations Map 5
3 Municipal, Residential, and Commercial Wefl Location Map 13
4 Monitoring Wells Installed Through and Including Phase II Remedial Investigation Sites 1, 2,
and 3 14
5 Monitoring Wells Installed Through and Including Phase II Remedial Investigation Sites S, 6.
and 7 19
6 Location of Sampled Off-Site Wells and summary of VOC Sample Results 24
TABLES
NUMBER PAGE
1 Summary of Waste Management and Site Operations 4
2 Occurrence and Distribution of Monitoring Wefl Organics - Sites 1, 2, and 3 15
3 Occurrence and Distribution of Unfiftered Monitoring WeU Inorganics - Sites 1, £ and 3 ... 16
4 Occurrence and Distribution of Flered Monitoring WeU Inorganics - Sites 1,£ and 3 17
5 Occurrence and Distribution of Monitoring Wen Organics - Sites 5, 6, and 7 20
6 Occurrence and Distribution of UnfPtered Monitoring Wefl Inorganics • Sites 5, 8, and 7 ... 21
7 Occurrence and Distribution of Fftered Monitoring Wefl Inorganics - Sites 5, 6, and 7 22
8 Occurrence and Distribution of Volatile Organic Contamination in Area 1 25
9 Occurrence and Distribution of Surface Water Inorganics Near Stes 1,Z and 3 27
10 Occurrence and Distribution of Surface Water Organics Near Sites 1,2, and 3 28
11 OoojrrenceartfDWnlxjtton of Volatile Orgarfc 29
12 Occurrence and Distribution of Surface Water Inorganics Near Stes 5,8, and 7 .30
13 Occurrence and Distribution of Surface Water Organics Near Stes 5, 6, and 7 31
14 Summary of Noncarcinogenic Risks - Stes 1,2, and 3 Greundwater (Current) 33
15 Summary of Carcinogenic Risks • Sites 1, Z and 3 Groundwater (Current) 34
16 Summary of Noncarcinogenic Ingestion Risks to Adult Residents - Sites 1, £ and 3-Modified
with Fftered Inorganics (Potential Current Exposure) 38
17 Summary of Carcinogenic Risks Current Groundwater • Stes 5,6, and 7 37
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RECORD OF DECISION
NAVAL AIR DEVELOPMENT CENTER
DECISION SUMMARY
L STTE NAME. LOCATION. AND DESCRIPTION
The Naval Air Development Center is a 734-acre Naval facility located in Warminster Township, Bucks
County, Pennsylvania (the Site-) (see Figure 1 for Site Location Map). In January 1993, the Naval
facility was renamed Naval Air Warfare Center (NAWC) Aircraft Division Warminster. The Site lies in a
populated suburban area surrounded by private homes, various commercial and industrial activities,
and a golf course. On-site areas include various buildings and other complexes connected by paved
roads, the runway and ramp area, mowed fields, and a small wooded area
The longest runway, which is currently the only active runway, is generally located along the
topographically highest area at the Site. Many of the primary NAWC buildings are located west of the
airstrip, along Jacksonville Road, a pubUc road which traverses the Site north to south. A housing
development for military enlisted personnel is within the southeastern portion of the Site. A
wastewater treatment plant (WWTP) owned and operated by NAWC is located in the northwestern
comer of the Site.
Commissioned in 1944, NAWC's main function is research, development, testing, and evaluation for
Naval aircraft systems. NAWC also conducts studies in anti-submarine warfare systems and software
development
NAWC has approximately 3,000 employees, and 1,000 people reside at the Site year round. The
residents living at the Site are the nearest population center. The closest off-base home is about 200
feet away from the NAWC property fine. Residential development is located along the length of the
southern property fine of NAWC, and to a lesser extent, along the northern property One. Industrial
development is located along the west and northwest perimeter of NAWC property. Qroundwater is
used extensively as a source of water by both residents and industry in the immediate vicinity of the
Site. The Site is located on a ridge, generally oriented east-west, with elevations ranging from 297
feet at the northwestern property boundary to 377 feet at the eastern boundary. Onsfte slopes are
gentle and average three to five percent
The northern portion of the Sie (about 65 percent) drains into smafl. unnamed tributaries of Uttto
Neshaminy Creek. The remaining portion (about 35 percent) drains into unnamed tributaries of
Southampton Creek. These streams are used for recreation and industrial purposes. An unnamed
tributary of Little Neshaminy Creek which flows immediately adjacent to the NAWC property Bne may
be used for recreational purposes by children approximately 3000 feet downgradtent of the Ska
There are no known endangered species or critical habitats within the immediate vidnfty of the Ste.
TWs section describes the history of waste dsposaJ, and CERCLA invesdo^tkxis and response actions
attheStta
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;— -f x,.'• 'if —raw'
^•'
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A. HISTORY OF WASTE D6POSAL
Historicalfy, wastes containing hazardous substances have been generated by NAWC during aircraft
maintenance and repair, pest control, fire-fighting training, machine and plating shop operations, spray
painting, and various materials research and testing activities in laboratories. The wastes generated
have included paints, solvents, sludges from industrial wastewater treatment, and waste oils. From
1940 to 1980, these wastes were disposed in pits, trenches, and landfills located on current NAWC
property. In addition, wastes generated by NAWC were burned in a fire training area until 1988.
To date, eight (8) areas on current NAWC property have been identified as areas used for the
disposal of wastes containing hazardous substances. A brief summary of these eight areas is
provided on Table 1 -1. Figure 2 provides the locations of these eight waste disposal areas, which
cover approximately seven acres. None of these areas are currently used for waste disposal. For
investigative purposes, sites 1, 2 and 3 have been grouped into Area A, while sites 5, 6 and 7 have
been grouped into Area 8.
1. Area A
Site 1 is located on a portion of the NAWC property facility lying northwest of Jacksonville Road and is
adjacent to the NAWC wastewater treatment plant Site 1 is within 1,000 feet of an off-site food
processing facility located outside of NAWC property and within 300 feet of an unnamed tributary of
Little Neshaminy Creek. Site 1 was operated as a bum pit within an eroded ravine from 1940 to 1955.
Various wastes such as paints, oils, asphalt roofing material, solvents, scrap metals, and unspecified
chemicals were burned within this pit The quantity of wastes deposited or burned is unknowa The
estimated area of site 1 is approximately 2,500 square feet
Site Z located about 300 feet southeast of site 1, received wastewater sludges from 1965 to 1970.
Site 2 consisted of two disposal trenches; each trench was approximately 12 feet wide by 200 feet
long by eight feet deep. The total area of site 2 may be 20,600 square feet
Site 3 is immediately southeast of site 2. Site 3 was used from 1955 to 1965 as a bum pit for
solvents, paints, roofing materials, and other unspecified chemicals. The pit was approximately 20 feet
wide by 30 feet long by 10 feet deep. Residue from the pit was occasionally removed and deposited
at an unknown area of the NAWC property.
2. AreaB
Site 5 is located adjacent to and under several housing units in NAWC's enlisted men's housing area.
Site 5 operated from 1955 to 1970 and was unearthed during construction for the foundation of a
housing unit Site S reportedly consists of six to eight disposal trenches in which paints, solvents,
scrap metal, demoBBon debris, and 30 drums of asphalt were disposed. Each trench was reportedly
about 12 feet wide by 70 feet long and eight feet deep.
Site 6 reportedly consists of an unknown number of disposal pits or trenches on the south side of the
main runway. This site received paint, solvents, demolition waste, waste oils, flammable waste, and
grease trap waste from 1960 to 1980. The site covers an area of about 70,000 square feet Uttie
information is avaBabJe regarding waste disposal operations for site 6.
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TABLE 1
SUMMARY OF WASTE MANAGEMENT AND SITE OPERATIONS
NAWC WARMINSTER. PENNSYLVANIA
8fTE
NO.
1
3
6
6
8
DATES OF
OPERATION
1940 10 1966
1965 to 197D
1955 10 1986
4OOA *A 4AYA
1WO tO ivTU
1956 to 1970
1960 to 1960
4OKA In 1OKR
IVBW IU I^OB
1961 to 1966
TYPES OF WASTES
PaMs, da, asphalt, roofing material, unspecified
chemicals, firing range wastes
but >lal t*MO**n.,,nl L u4na«
wastewater sludges
Solvents, pans, roofing materials, and unspecified
chemicals
NonHnousmaj soso wastes, paras, waste OHS, waste
metals, construction debris, solvents, and sewage
treatment studoe
PaMs, advents, scrap metal, and 30 drums of asphalt
Paints, solvents, demoHUon wastes, waste ass, other
flammable wastes, and grease trap wastes
Inrfc laiiirf iirnfltniimtar ah tfinA
Aviation fuel, lubricanU, coolants
METHOD OF
OPERATION
Bum pit within an
eroded ravine
2 disposal
trenches
Bum pit
urapoggi
trendies
6 to 8 disposal
trenches
Unknown number
fA HlttrkAOal i^to ftf
W um|JWKii J*"» m
trenches
2disnosal
tranches
Flrefightlng
training area
POTENTIAL HAZARDS
Various solvents, driers,
pigments, PAHs, creosote,
phenols, asbestos, binders,
toad
Biological wastes, heavy
metals
Various solvents, driers,
pigments, asbestos, binders
various soivenis, oners,
pigments, toad, PAHs,
biological wastes heavy
metals
Various solvents, driers,
pigments, creosote, phenols,
PAHs
Various solvents, driers,
pjgmefns, leaa, PAHS
Rlnlnnicfil u/AAtAo HOAUU
metals
PAHS.PCB8
ADAPTED FROM SMC MARTM1891 (TABLES 1-1 AND 4.3-4)
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z
NAWC WARMINSIER
WASTE DISPOSAL IOCA1IOUS MAP
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Site 7 is located west of sites 5 and 6 and east of the inertia! reference building. Site 7 reportedly
consists of two disposal trenches that were used from 1950 to 1955 to receive sludge from the
wastewater treatment plant The trenches were reportedly 100 feet long by 12 feet wide and eight feet
deep. The potential capacity of each trench is 356 cubic yards. The trenches were reportedly
backfilled with fill after each dumping episode.
a CERCLA INVESTIGATIONS AND RESPONSES
The EPA completed CERCLA Preliminary Assessment (PA) and PA/Site Inspection (SO Reports in
1979 and 1985 respectively. In 1986, the Site was proposed for inclusion on the National Priorities Ust
(NPL). On October 4,1989, the Site was placed on the final NPL On September 20,1990, the Navy
and EPA signed an Interagency Agreement (IAG) which established a procedural framework for
developing and implementing investigative and response actions at the Site in accordance with
CERCLA and the NCP.
In response to the inclusion of the Site on the NPL and in accordance with the IAG, the Navy has
investigated hazardous substance releases at the Site in two phases to data A Phase I Remedial
Investigation (RQ was initiated in late 1988 and was completed on September 11,1990 with the
release of the Phase I RI Report Phase I initiated the investigation of sites 1 through 8 by screening
these sites for volatile organic compounds (VOCs) via soil gas analysis and detecting any burled
materials through electromagnetic surveys. The sites were also investigated through soil borings and
the installation and sampling of shallow monitoring wells instated to rrwnitor overburden and shalow
bedrock aquifers. In addition, test pits were excavated, nearby wells were inventoried, and a bedrock
fracture-trace analysis was conducted.
The Phase II RI was inflated in late 1991. Phase H work included the installation of additional
overburden and shadow bedrock monitoring wells, sampling and analyzing groundwater, and an
evaluation of aquifer characteristics through water-level monitoring, slug and step-drawdown tests and
a pumping test Four off-site wefls were sampled during the Phase IIRL
Both the Phase I and Phase II RI investigated the nature and extent of shallow groundwater
contamination wtthin Areas A and a The Phase 0 RI also investigated the potential for groundwater in
the shallow bedrock aquifer underlying Area A to migrate to offsto locations, including doopor
aquifers. The findings of the Phase D RI and a summary of the Phase I RI were included in the Phase
II RI Report for OU-1 released on Apr! 19,1993.
On Apr! 21,1993, the Navy released a Focused Feasfeffity Study (FFS) Report for OU-1 at the SKe.
The FFS for OU-1 developed several remedaJ aJtamatives for mrtrnftng the nrvgration of
contaminated groundwater in overburden and ahalow bedrock attributable to NAWC.
During the week of Apr! 28,1993, the Navy inflated the sainplng of offsto wefls to assess the impact
of contaminated groundwater attributable to NAWC on offsto groundwatar users. Through July 30,
1993, the Navy had sampled over 200 wets. Seven (7) residential wefts sampled exceeded EPA
Removal Action Levels, whfle an addtonal thirty (30) residential weBs exceeded Maximum
Contaminant Levels (MCLs) (developed pursuant to the Safe OrMdng Water AcQ. At toast part of this
contamination is potentiafly attributable to the Ste. In response, the Navy has conducted a CERCLA
removal action, instaffing a water treatment system in each residence where either EPA Removal
Action Levels or MCLs have been exceeded.
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The EPA determined this offsite groundwater contamination constitutes an imminent threat to human
hearth. In response, the EPA and the Navy are conducting additional CERCLA removal action work
which shall provide residences exceeding EPA Removal Action Levels and MCLs as weB as
residences in the immediate path of the groundwater contamination with connections to public water
supply systems.
UL HIGHLIGHTS OF COMMUNJTY PAffnOPATTON
Since 1988, the plans and results of CERCLA investigations and actions have been presented to a
Technical Review Committee (TRC) for the Site. The TRC includes representatives of Bucks County
Health Department, Warminster Township, Warminster Township Municipal Authority, Upper
Southampton Township, Upper Southampton Water and Sewer Authority, Northampton Township and
Northampton Municipal Authority.
In accordance with Sections 113 and 117 of CERCLA, 42 U.S.C. Sections 9613 and 9617, the Navy, in
conjunction with EPA, issued a Proposed Plan on April 29,1993, presenting the preferred interim
remedy for OU-1. The Proposed Plan and Rl and FFS reports for OU-1 were among those documents
included in the Administrative Record on April 29,1993. The Administrative Record is available for
review by the public at the following information repositories:
• MA WC Public Affairs Office
Jacksonville Road (Building 3)
Warminster, Pennsylvania 18974
• Bucks County Library
150 South Pine Street
Doytestown, Pennsylvania 18901
An announcement of the public meeting, the comment period, and the availability of the Administrative
Record for the interim remedy for OU-1 was published in the Philadelphia Inquirer. Intelligencer. Public
Spirit and Courier Times on Apr! 29 and 30,1993. Minor corrections to this announcement were
published in the Philadelphia Inquirer. Inteffloencer. and Courier Times on May 10,1993. Additionally,
the Proposed Plan and the Notice of AvaOabfflty were mailed to local municipal and government
agencies in the vicinity of the Site.
The pubfic comment period for the Proposed Plan was from Apri 29,1993 to May 28,1993. A pubic
meeting was held at Wifiam Termant High School, Centennial Road, Warminster, Pennsylvania on May
10,1993 to present the n, FFS and Proposed Plan, answer questions, and accept both oral and
written comments.
A transcript of the meeting was maintained in accordance with Section 117 (a) (9 of CERCLA, 42
U.S.C. §96l7(a)(2). As a resut, responses to many oral comments during the pubic mooting are in
the transcript of the meeting, which is now part of the Administrative Record. Responses to written
comments received during the puttie comment period are included in the Responsiveness Summary
section of this ROD.
This Record of Decision presents the selected Interim remedial action for OU-1 at the Ste chosen in
accordance with CERCLA and, to the extent practicable, the National Contingency Plan (NCP).
M documents considered or relied upon m reaching the remedy selection decision contained in this
ROD are included in the Administrative Record for the Site and can be reviewed at trie Wbmation
repositories.
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IV. SCOPE AND RQig OF IMS REMEDIAL ACTION
Section 300.430 (a)(1)(ii)(A) of the NCP, 40 C.F.R Section 430(a)(1)(iQ(A) provides that CERCLA NPL
Sites 'should generally be remediated in operable units when early actions are necessary or
appropriate to achieve significant risk reduction quickly, when phased analysis or response is
necessary or appropriate given the size or complexity of the Site, or to expedite the completion of a
total cleanup.* OU-1 at the Site has been identified to facilitate these objectives.
This ROD selects an interim remedial action for contaminated groundwater attributable to Area A and
Area B at the Site in overburden and shallow bedrock aquifers. Contaminated groundwater
attributable to Area A and Area B at the Site in overburden and shallow bedrock aquifers has been
designated as OU-1. This groundwater presents unacceptable risks to human health and sufficient
information is available to select an interim remedy at this time.
The objective at the interim remedy in this case is to minimize the migration of contaminated
groundwater attributable to Areas A and B at the Site in overburden and shallow bedrock aquifers
while additional Rl work is performed to determine the fun nature and extent of contamination in these
aquifers both on and off current NAWC property. The additional Rl work to be conducted by the Navy
will include additional monitoring well installation, groundwater sampling, long-term water-level
monitoring, and aquifer testing as necessary.
The final remedy for OU-1 win be selected after the fun nature and extent of the problem are identified
and will consider the information generated during implementation of the interim remedy. In the
Preamble to the publication of the revised NCP, it is noted that operable units 'may include interim
actions (e.g., pumping and treating of groundwater to retard plume migration) that must be followed
by subsequent actions which fufly address the scope of the problem (e.g., final groundwater operable
unit that defines the remediation level and restoration timeframe).' (55 FedReg. at 8705 (March 8,
1990)). Therefore, a final ROD for OU-1 wM be issued after the implementation of the interim action.
The interim action will be consistent with planned future actions to the extent possible.
Other media associated with the Site, including groundwater in deep bedrock aquifers, wastes, soils,
sediment and surface water wffl be further investigated under the RVFS process. Additional remedial
actions win be proposed and selected as soon as adequate information exists to support the selection
of a remedy for a particular medium or group of media. Any such medium (or group of media) will be
designated as an Operable Unit by the Navy and EPA. At this time, only OU-1 has been designated
by the Navy and EPA.
V. SUMMARY OF SITE CHARACTERISTICS AND EXTENT OF CONTAMPMTTON
Summarized below are the relevant findings of the Rl to date with regard to groundwater in
overburden and shallow bedrock at the Site.
A, SITE CHARACTEFBSTICS
1.
The Site is located in the Piedmont Physiographic Province, Trfassic Lowlands Section, of
southeastern Pennsylvania The land forms have been modffied by erosion to form moderate slopes
and gently rounded nils with a dendritic drainage pattern.
8
-------
Surface sods in the vkantty of the Site are generally fine-textured, predominantly sflty loams, with
moderate to low permeabilities. The soils are commonly underlain by saprotite (extensively weathered
bedrock) at an approximate depth of four to 10 feet Available information indicates saprolite on
NAWC property varies from eight (8) and twenty-five (25) feet in thickness.
The bedrock underlying the saprolite belongs to the late Triassic age middle arkose member of the
Stockton Formation. These rocks consist of fine- to medium-grained arkosic sandstone interbedded
with red shale, siltstone and conglomerate. Units of varying lithology are irregularly interbedded with
coarse-grained units commonly overlying fine-grained units. Individual beds commonly pinch out or
form gradational contacts with overlying or underlying beds over lateral distances greater than several
hundred feet
The beds of the Stockton Formation strike to the northeast and dip from seven to 16 degrees to the
northwest with an average dip of 12 degrees. The thickness of the middle arkose member of the
Stockton Formation is estimated to be approximately 500 feet near the southeastern property
boundary of NAWC, increasing to between 1,500 and 2,000 feet near the northwestern boundary. The
Stockton Formation is extensively faulted and is cut by a well-developed joint or fracture system.
2, Hydrogeotogy
The Stockton Formation forms a multi-aquifer system of relatively discrete water-bearing zones
separated by thicker, less permeable zones. Transmissivjty and groundwater movement within water-
bearing zones are greater paraflel to bedding than across bedding. Vertical or nearly vertical fractures
cutting across bedding and the weathering of various beds are expected to permit varying degrees of
leakage between the main water-bearing zones, particularly near the surface. Groundwater in the
Stockton Formation occurs locally under both confined and unconfined conditions.
Within water-bearing zones in the fine- and rneoTunvgrained sandstone of the Stockton Formation,
groundwater is transmitted through primary intergranular porosity, as wed as along fractures, joints,
and bedding planes (secondary porosity). The shale and siltstone beds are commonly too fine-
grained to transmit large amounts of groundwater through primary porosity, and fractures and joints
are typically not weU developed in these fine-grained beds. Consequently, the snate and siltstone
beds often act as confining layers to groundwater. Fracture permeability is generally better developed
in the sandstone layers compared to the shale and sittstone layers of the formation. This, along with
greater primary permeaofflty, alows the sandstone layers to function as the most productive water-
bearing units of the Stockton Formation.
-------
The regional hydrogeotogy tor the Stockton Formation in the area around the Site is that of a complex
mufti-aquifer system. The individual water-bearing zones of the Stockton Formation may belong to
either of three different aquifer types based on their storage coefficients, leakage factors, and spatial
relationships. In descending order, these aquifer types include:
• Overburden aquifers
• Shallow bedrock aquifers
• Deeper bedrock aquifers
With the exception of the overburden, these aquifer types are not interpreted to necessarily represent
physically distinct units but to represent transitional zones that occur within the individual water-
bearing units encountered at increasing depths.
The overburden aquifers consist of saturated soite and saprolite derived from erosion of the truncated
edges of the inclined bedrock layers. They extend to depths of 15 to 35 feet, with an average depth
of 20 feet The overburden controls the rate at which water percolates to the water table. Saturated
conditions do not exist within the overburden at all locations throughout the Site. Interpretation of
overburden water-tabte elevations indicates that an unnamed tributary of Uttie Neshaminy Creek acts
as a groundwater divide for the overburden aquifer in the vicinity of Area A. Based on available
information, it is unknown whether a tributary to Southampton Creek acts as a divide for groundwater
in overburden south of NAWC property in the vicinity of Area B.
The shallow bedrock aquifers underlie the overburden aquifers have been considered to extend to a
depth of 100 feet below the ground surface. The shallow bedrock aquifers ana recharged by vertical
percolation from the overburden aquifers and are the prirrary reserved for p/oundwater storage in the
Stockton Formation. The shallow bedrock aquifers are generally under water-table conditions and
may consist of numerous discrete water-bearing zones. The hydrauBe characteristics of the shallow
aquifers are primarily controlled by the physical properties of the bedrock. Horizontal groundwater
migration in response to regional gradients (controlled by topography or long-term weB pumping) '»
probably significant ft. the shalow bedrock aquifers.
The deeper bedrock; aquifers underlie the shallow bedrock aquifers and have been considered to
occur at depths of greater than 100 feet below the ground surface. Pumping water from the deeper
aquifers induces leakage from the shalow bedrock aquifers. This is the manner in which water stored
in the water table provides recharge to the deeper portions of the Stockton Formation.
The transition in the water-bearing zones from unconfined to confined conations varies between
particular areas and occurs at afferent depths within bedrock. Leakage of water from the shafow
bedrock aqutfflfs to deeper bedrock aquihMS also varies with tocmton and dopth. In general, the
Stockton Formation is a complex muHpte aquifer system with beds of varying permeabifty and
fracturing. Most deep weOs In the Stockton Formation penetrate several inajor water-bearing zones
and, if aflowed to remain open through these zones, are mufraquBerweBs. The individual water-
bearing zones of a given we! generaOy have afferent hydraufic properties and dBferent hydraufc
heads. Therefore, the hydrautc head of • mutt-aquifer weB is a composite head of at the water-
bearing zones in which I is completed. In unused supply wete and monitoring web that are
completed in more than one major water-bearing zone, groundwater is free to flow from water-bearing
zones of higher hydraulc head to those of lower hydraufic head.
10
-------
a Hydrotogy
This Site is located in an upland area lying between two local drainage basins. The northern 65
percent of the Site (including Area A) drains toward the north through several swales and storm
sewers into small unnamed tributaries of Little Neshaminy Creek. The southern 35 percent of the Site
(including Area B) drains toward the south to the headwaters of Southampton Creek, a tributary of
Pennypack Creek. Both local drainage basins lie within the regional drainage basin of the Delaware
River. Various studies conducted on the Site have revealed that no areas within the Site are included
in the 100-year or 500-year floodpiains.
Much of the natural drainage pattern has been altered by development, and drainage within
developed areas of the NAWC property is controlled primarily through constructed drainage systems.
A significant portion of precipitation runoff is directed by surface grading and paving to constructed
ditches; culverts, and storm sewers. Several of the tributaries of little Neshaminy and Southampton
Creeks originate at, or near, the outfall points of these culverts adjacent to the NAWC boundary.
Springs and seeps contributing to surface water flow have been reported or observed near the facility
boundary in the vicinity of Areas A and B. An underground tile drainage system was used to drain the
eastern portion of NAWC when it was farmed in the 1940s. The present conditions of the tile drains
and their influence on surface or near-surface drainage are unknown.
4. Moroonalogy
The cfimate of the area is humid continental and is modified by the Atlantic Ocean. Temperatures
average 76°F (24.4aC) in July and 32T (0°C) in January. The average dafly temperature for the NAWC
location is sa3°F (11.8°C). Precipitation averages 4Z5 inches per year (106.25 cm per year), and
snowfall averages 22 inches per year (55 cm per year). The distribution of precipitation is fairly even
throughout the year. The relative humidity for the Site averages 70 percent The mean wind speed
for this area is 9.6 mph, with a prevailing direction of west-southwest
& Ecology
Open land, woodland, and wetland habitats are aO found within or near the Site. These include
mowed fields and lawns, nonforested overgrown land, wooded areas, forested wetlands, scrub/shrub
wetlands, and streams with associated riparian areas.
There are no permanent threatened or endangered species on or near the Sfte; however, some
transient species do traverse the area No areas have been designated as wetlands on NAWC
property according to Army Corps of Engineers criteria. A wetlands assessment must stil be
completed for off-base areas.
Mourning doves, pheasants, and various songbirds such as sparrows, red-winged black birds, gold
finches, cardnate, blue jays, and robins are present throughout the Ste. Canada geese and ducks
have been observed in the streams south of Area B and north of Area A. Snakes, leopard frogs, and
muskiats have ateo boon observed In or near the stream nmili of this ares. Snate, earthworms,
amphipods, and larval Insects have also been observed. Smafl fish or minnows tentatively identified
as creek chubs are present in each of the streams from which surface water and sedment samples
were obtained. Whtte-tafled deer, groundhogs, rabbits, and squirrels are common throughout the
fadty. Raccoon tracks have been observed in several adjacent streams.
11
-------
a Sato
The Site is underlain by soils of the Lansdate-Lawrenceville Association. This unit consists of nearly
level to sloping, moderately wen-drained soils and well-drained soils on uplands. The soils are deep
and have a medium-textured surface layer and a medium-textured or moderately coarse-textured
subsoil They formed in material weathered from shale and sandstone and in sflty, windblown
deposits. They consist primarily of silt loam, shaly silt loam, sitty day loam, and some sandy loam.
Some of the soils In this association have a seasonal high water table and restricted permeability.
Large portions of the Site are urban land areas where the original soils have been graded, disturbed,
filled over, or otherwise altered prior to construction of the base facilities. Various types of ffl material,
including the contents of the known waste areas at the Site, are included in the urban land areas.
Much of the area is covered by paved surfaces, buildings, or other engineered structures.
«.
7. Graundwater Use
Groundwater is the primary source of residential, industrial and commercial water supplies in the
immediate vicinity of the Site. The groundwater is provided either through individual, privately owned
wells or by larger supply systems which have their own wefls. The systems of concern include those
owned by the Warminster Municipal Township Authority, Upper Southampton Municipal Authority.
Northampton Municipal Authority and the Warminster Heights Development Corporation. From Apr! to
July 1993, the Navy identified and sampled over 200 private residential wefls within an approximately
3,000 foot radius of Area A and Area 8. In addition, 3 commercial wefls are known to be located
wiWn 1,000 feet of Area A, Fina*y, NAWC is suppfied by to own system and associated wets. Based
on available information, the location of known municipal residential and commercial supply wefls in
the vicinity of the Site is provided in Figure a The dotted Ine in figure 3 depicts the area where
residential wete were identified and sampled through July 1993. Trie area of residential wete sampled
in the vicinity of Area A was designated as Area 1, whte the area of residential wefls sampled in the
vicinity of Area B was designated Area 2
& NATURE AND EXTENT OF CONTAMINATION
The findings of the Rl to date wih respect to groundwater in overtxjrden and shaflow bedrock aquiers
are provided in detaB within the Phase II n report A summary of the major findings for Area A, Area
B, and offstte locations respectively is presented below. Representative (or •average1) concentrations
of groundwater contaminants for Areas A and B were calculated as part of theRL
1. Area A
Al monitoring weB* in the vicMy of Area A are depicted in Figure 4. Al of these wefe are located on
NAWC property and mentor groundwater in either overburden or shaflow bedrock with the exception
of Wei SMC-& whten mentors the deeper bedrock aquifer. Table 2 summarizes the occurrence and
attribution of organic* in wefls downgradtent of Area A, whto Table* 3 and 4 summarize the
occurrence and distribution of inorganics (metals) in unfQtered and fltered samples, respectively, bom
the same wefls.
12
-------
AIR
WARFARE CENTER
WARMINSTER
8/19/93
MOO - 400Q MUNICIPAL RESIDENTIAL AND COMMERCIAL
SCWMM rar " """"^ MfELL LOCATION UAP
NAVAL AIR WARFARE CENTER. WARUINSTER, PENNSYLVANIA
Halliburton NUS
CORPORATION
-------
SHMIOW BtDKOCK
MONIIUMMG WELL
DEEP HtOROCK
MONI10WNG WELL
W'PKOX
LOCATION
NAWC
WANMINSTER. PA
MUNiroRING WIIIS INSTA1I
THROUGH AND INCIUDIN(
PHASE II REMCOIAI INVESTICA1
SUES 1.2 AND 3
(CQN10UR INItHVAL 10 KCT}
Halliburton Nl)
COKPORATIO
lion SUC CmMMMllM
IMl
-------
TABLE 2
OCCURRENCE AND DISTRIBUTION OF MONITORING WELL ORGAMCS -SITES 1, 2, and 3
NAWC, WARMNSTER. PENNSYLVANIA
Compound
Vinyl chloride
l,t-Oichkxoethene
1,1-Ofchloroethane
1,2-Otenloroetnene
Cte-1 ,2-Ofchtoroethene
1.2-Otehloroethane
Trtcnioroetrwns
TetracnioroetnenB
1,1,1-Tricntoroethane
Chloroform
Cartxxi tetrachloride
Benzene
Tw*KLji_».nfli a.iB, jhrMin
ncnioronuoronMinsne
Toluene
Ethylbenzene
Xytenes
1 ,2-Oichlorobenzene
1,2-Oichkxopropane
2-Butanone
OMvoctylphthlate
Dkxnylpnthalate
rnenantnrene
rU um»«ia>tjtj^jt
Fuorantnene
Pyrene
TICs
CRQL
1/10
1/5
1/5
5
1/5
1/5
1/5
1/5
1/5
1/5
1/5
1/5
5
1/5
1/5
1/5
1/10
1/5
5/10
10
10
10
10
10
-
Frequency
of
Positive
Detection
1/24
13/24
14/24
6/11
5/13
4/24
19/24
11/24
9/24
5/24
6/24
3/24
3/11
2/24
1/24
1/24
3/24
1/24
1/13
5/12
3/12
1/12
1/12
1/12
3
Range
of Positive
Detection
1.5
0.175-3
1-a
1-62
2-510
3-3.5
0.75-2100
3*440
2-10
6-25
1044
0.95-2
10-91
3-4
0.2
2
0.4-0.7
1
24
0.34
02-0.375
O3
0.8
0.6
+
Rep Cone
1.5
3.0
ao
27.0
138
as
469
128
10.0
13.8
16.8
ZO
29.8
4.0
02
ZO
a?
1.0
24.0
ao
0^75
O3
ae
as
-
TICs * Tentatively identified compounds
CRQL - Contract Required Quanttatton Umt
Hi«burtonNU8Co>pQMMonPh>MtR>m»fl»»rtla^tontUpo««.Apti 1883
15
-------
TABLES
OCCURRENCE AND BSTOBl/nON OF UNFILTERED MONTTORMG WELL NORGANICS
SITES 1,Z and 3
NAWC, WARMNSTER. PENNSYLVANIA
(ug/L)
Element
Aluminum
Arsenic
Barium
Cadmium
Calcium
Chformum
Cobatt
Coooer
*•**?*?*•*•
Iron
Lead
MaQnesiufn
Manganese
Mercury
Nickel
Potassium
S*er
Sodkjm
Thafium
Vanadium
Zinc
CRDL
200
10
200
5
5000
10
50
25
100
3
5000
15
02
40
5000
10
5000
10
50
20
Frequency
of
Positive
Detection
15/24
7/24
13/24
4/24
13/24
13/24
10/24
7/24
21/24
16/24
13/24
22/24
3/21
9/24
12/24
2/24
13/24
1/24
6/24
10/24
Range
of Positive
Detection
854-158000
2-67.5
47^620
643
30900-158400
25-220
2-118
30.5-1660
4330.126280
1.2-325
908048500
5342100
O3-0.67
10-121
10304110
4-20
1090&42SOO
2
14-101
22-1660
Representative
concentration
25820
10.6
873
9.6
63520
49.4
22,8
236
42010
85.5
24120
5410
022
43.6
2850
S58
21230
1.14
243
400
CRDL
Contract Required Detection LJmft
. Htfburton NUS Cefperafan Ph«M B
1908
16
-------
TABLE 4
OCCURRENCE AND DSTRBUTON OF FILTERED MONITORING WELL INORGANICS
SITES 1,2. and 3
NAWC. WARMINSTER. PENNSYLVANIA
Element
Barium
Calcium
Chromium
Iron
Lead
Magnesium
Manganese
Potassium
Sodium
Vanadium
Zinc
CRDL
200
5000
10
100
3
5000
15
5000
5000
50
20
Frequency
of
Positive
Detection
13/13
13/13
1/13
6/13
3/13
13/13
13/13
9/13
13/13
1/13
5/13
Range
of Positive
Detection
29*343
30600-60700
31
37-4840
1.6-6
8750-21950
26-4190
723-3360
10400-40300
6
6-174
Rep Cone
210
51230
9.6
1860
1.86
19150
1310
2080
28140
a39
48.9
CRDL - Contract Required Detection Urn*
Adoqttd from - Htffewton NUS Cwpoaflon Ph«t 11
i ftaport, April19B3
17
-------
The most frequently detected organics within Area A, in order of descending frequency, included
trichloroethene, 1,1-dlchioroethane, 1,2-dtehtoroethene, cis-l^-dichloroetnene, 1 J-dtahloroethene, and
tetrachloroethene. The highest representative concentrations were trichloroetherw (440 micrograrns
per liter (ug/l», cB-l,2-dichkxoetnene (138 ug/I) and tetrachloroethene (128 ug/I). The maximum
concentrations detected were trichloroethene (2,100 ug/I), cts-1,2-dichloroethene (510 ug/I) and
tetrachloroethene (440 ug/I).
Toxic or carcinogenic metals with significant representative concentrations in filtered and/or unfiltered
samples included lead, iron, copper, arsenic, manganese, thallium, barium, cadmium and nickel
The inferred groundwater flow direction in both overburden and shallow bedrock under Area A is to
the north. A water-level study, combined with groundwater analytical data, suggest that contaminated
groundwater in the shallow bedrock underlying Area A has migrated to deeper portions of the aquifer
north of NAWC property. The Phase II Rl Report concluded that the fufl nature and extent of
overburden and shallow bedrock groundwater contamination attributable to Area A have not been
determined at this time.
As noted previously (see Groundwater Use Section), a significant number of residential wells are
located within a 3,000 foot radius of Area A. Based on a review of available information, these wells
could be potentially affected by groundwater contamination attributable to Area A in overburden and
2. AraaB
Monitoring wells instated In the vicinity of Area B are depicted in Figure & As noted, al of the wefls
are located on NAWC property and monitor groundwater in overburden or shaBow bedrock. Table 5
summarizes the occurrence and dtetrfbutton of organics in wefls wftrrin Area B, whBe Tables 6 and 7
summarize the occurrence and distribution of inorganics (metals) in unffltered and fttered samples,
respectively, from these wefb.
The most frequently detected organics within Area B, in order of decreasing frequency, included 1,2-
dtehloroethene, trichloroethene, tis-1,24ichtoroethene, toluene and carbon tetrachtorida The highest
representative (mean) concentrations were for trichloroethene (4.4 ug/I). 1^-dfchkxoethene (3.8 ug/Q
and cts-l,2-o1chloroethene (2,6 ug/I). The maximum concentrations detected were trichloroethene (13
ug/Q and cts-l,2-dtenloroethene (8 ug/I).
Toxic or carcinogenic metals win significant representative concentrations in unfikered and/or fttered
wei samples included arsenic, barium, cadmium and manganese.
Based on water level measurements conducted during the H. the inferred flow of groundwater in both
overburden and shaBow bedrock under NAWC properly in tne vfdnfty of Area B is to the south. The
Phase H n Report concluded that the ful nature and extent of overburdea shaBow bedrock and deep
bedrock groundfratar contamination attributable to Area B riave not been determined at this ttrna
As noted previously (see Groundwater Use Section), a skjnBcant number of residential wefe are
located within a 3,000 footradkjs of Area B. Based on a review of avaaabto information, these wefls
could be potentfaly affected by groundwater <»ntarninatkxi attributabte to Area B In overtxjrcten and
shaBow bedrock.
18
-------
N 3ZB.CCC
-EGEND
O OVERBURDEN
06-1 MONTTORINC WELL
4. SHALLOW BEDROCK
MONITORING WELL
TOPOGRAPHIC
CONTOUR L'NE
N
Si
0 40 -00
200 ffl)
NAWC
WAMMNSTCR. PA
-CURE t
MONITORING WELLS iNSTAU£3
THROUGH ANO INCLUDING
PHASE II REMEDIAL INVESTIGATION
SITES 5.6 ANO ?
(CONTOUR INTERVAL TO T~:
IN NUS
OATt 2/3/93
-------
TABLE 5
OCCURRENCE AND DtSTOBUTTON OF MONITORING WELL ORGAMCS - SITES 5, 6. and 7
NAWC. WARMINSTER. PENNSYLVANIA
Compound
1,2-Otehtoioethene
Tricntoroethene
^_
TetracntofoeuTene
Carton tetrachlonde
Cto-1 ,2-Dfchkxoethene
Cnlorornetnane
Cnkxoform
Toluene
1,1.1-Trichkxoethane
Di-n-octylpnthalate
DiMttylpntnalate
TICs
CRQL
5
1/5
1/5
1/5
1/5
1/10
1/5
1/5
1/5
10
10
-
Frequency
of
Positive
Detection
5/11
8/24
1/24
4/24
3/13
1/24
2/24
5/24
1/24
4/12
4/12
3
Range
of Positive
Detection
2-7
1-13
3
0.3-2
2-8
2
0.75-2
1-6
1
(L2-0.9
02-2
+
Rep Cone
as
4.4
1.8
1.6
2.6
2.0
1.4
2.4
1.0
as
2,0
-
TICs = Tentatively kJentMed compounds
CRQL » Contract Required Quanttatton Unit
Adopted tram - Htfburtbn NUS Coiporadon PttM* IR*
•DO*
•port. Aprt 1989
20
-------
TABLES
OCCURRENCE AND OCSTRBuTON OF UNRLTERED MONITORING WELL NORGANCS
STIES 5, 6, and 7
NAWC, WARMNSTER, PENNSYLVANIA
(ug/L)
Element
Aluminum
Arsenic
Barium
Cadmium
Calcium
Chromium
CobaJt
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Potassium
Sodium
Vanadium
Zinc
Cyanide
CRDL
200
10
200
5
5000
10
50
25
100
3
5000
15
40
5000
5000
50
20
10
Frequency
of
Positive
Detection
18/24
9/24
13/24
1/24
13/24
8/24
9/24
3/24
21/24
5/24
13/24
22/24
12/24
12/24
12/24
7/24
12/24
1/24
Range
of Positive
Detection
659-42000
2-12
75-969
2
11200-70800
4«7
2-120
40-166
224-97000
7.5-292
4000-23500
68-9565
10-98
817.5-23200
7660-28900
425-79
12-1300
92
Rep Cone
9660
3.4
388
2.0
336BQ
19.6
232
34.1
29120
7.1
13500
2000
32.3
5780
12670
1&3
228
26.3
CROL - Contract Required Detection Limit
AdopM from - HaHburton NU3 Cwpottfton PtaM 11
i Ftoport, Apt! U
21
-------
TABLE?
OCCURRENCE AND DISTRIBUTION OF RLTCRED MONITORING WELL NORGAMCS
STTES 5,6, and 7
NAWC, WARMINSTER, PENNSYLVANIA
Element
Barium
Calcium
Cobaft
Iron
Magnesium
Manganese
Nickel
Potassium
Sodium
ThaHum
Zinc
CRDL
200
5000
50
100
5000
15
40
5000
5000
10
20
Frequency
of
Positive
Detection
13/13
13/13
1/13
4/13
13/13
11/13
1/13
13/13
13/13
1/13
3/13
Range
of Positive
22-484.5
1280044700
6
1460-6630
4060-19800
17-753
25
420-18100
7070-31800
2
32-73
Rep Cone
214
41670
3.7
2600
14580
335
12.0
6020
17060
1.2
31.0
CRDL - Contract Required Detection Umt
Adopted from - HaBburton NUB Coporaflon RMM I FUmdtal tn**o*ton Ftoport. Aprt 1983
-------
Offsite wells sampled during the Phase II Rl included the following locations relative to Area A: a
municipal wefl 0.4 miles north, a commercial well 400 feet northeast, a second commercial well 1,200
feet east and one residential wefl 2,200 feet southeast (see Figure 6).
The municipal supply well, which is cased down to 70 feet and is 250 feet deep, was found to contain
several volatile organic compounds (VOCs) which have been detected in overburden or shallow
bedrock underlying Area A. Based on hydrogeotogic data presented in the Phase II PI Report, it is
unknown whether VOCs in overburden and shallow bedrock underlying Area A have migrated to this
municipal well However, this hydrogeotogic data suggests that contaminated groundwater in
overburden and shallow bedrock under Area A could potentially migrate to the municipal well of
concern.
Phase il Rl sampling found that the commercial wefl located 400 feet northeast of Area A contained
720 ug/l of trichloroethene (TCE). (This water is currently being treated by the commercial facility of
concern.) This information combined with Phase II Rl water level study data, other available
hydrogeotogic data and the detection of TCE in shallow bedrock underlying Area A suggests that
contaminated groundwater in the shaDow bedrock underlying Area A has migrated to this commercial
weU, which draws from an unknown depth north of NAWC property. The commercial wel 1,200 feet
east of Area A was found to contain 2 ug/l of tetrachJoroethene (PCE). The source of this trace
contamination is unknown at this time. Finally, no contamination was detected in the one residential
well sampled during the Phase II RL
As noted previously (see Groundwater Use Section), a significant number of additional residential,
commercial and industrial wells are located in the vicinity of Area A. Based on available hydrogeotogic
data, many of these wells could potentially be affected by contaminated groundwater in overburden
and shallow bedrock attributable to Area A. To initiate an assessment of the potential offsite impacts
of Area A. the Navy sampled afl known residential wells within Area 1 (see Groundwater Use section).
A summary of the results of this sampling effort within Area 1 is presented in Table a VOCs have
been detected in a number of these wells. Based on available information, the full nature and extent
of offsite overburden, shallow bedrock and deeper bedrock groundwater contamination attributable to
Area A cannot be determined.
The quality of surface water In an offste, unnamed tributary of Uttle Neshaminy Creek downgradient of
Area A has not been fuOy characterized at this time. To data, only two samples of surface water
downgradfent of site 3 (but upgradtent of site 1 and posstoly site 2) have been collected. The
analytical results for Inorganics and organics In these samples, as wel as upgradient background
samples, are summarized in Tables 9 and 10. These prefiminary results indicate elevated levels of
Iron, cadmium, copper and toad in surface water downgradient of sto 3. Based on avaflabte data, i is
uncertain whether these elevated levels are due to groundwater recharge of the stream.
23
-------
cattmw mi
NC: HA (9*0)
KT 7JO
i.i oa NO
I.I.I 1C* NO
I.I-OCA NO
LEGEND
9* • SIR
NO.
SAMPLED NEl
COMPOUND N
OCICC1EO AT
MTCCIMN Hi
SHOVN IN
PARCNTHCSCS
NAWC
WARMWSTER. PA
FIGURE 6
LOCATION OF SAMPLED
OFF SITE WELLS AND
SUMMARY OF
VOC SAMPLE RESULTS (ug,
|Halliburton Nil.1
C0RPORATIO
nm sue t»+mmmiH
MM
DATE: 2/9/93
C. \PWC\NAWC\079
-------
TABLE 8
OCCURRENCE AND DISTRIBUTION OF VOLATILE ORGANIC CONTAMINATION IN AREA 1
Chemical
Trichloroethene (TCE)
Tetraehloroethene (PCE)
1 ,1 -Ofchloroethene (1 .1 -OCE)
1.1-Dichloroethane (1.1 OCA)
1,1,1-Trtchkwoethane (1,1.1-TCA)
1 .1 ,2-Triehbroethane (1 .1 ,2-TCA)
cis-1.2-Dichloroethene (cis-1 ,2-OCE)
trans-1,2-0ichloroethene (trans-15-OCE)
1^-OJchhxoethane (1.2-DCA)
Carbon Tetrachtoride (CCIJ
2-8 uta none
TOTAL NUMBER OF WELLS SAMPLED IN
AREA 1
CRQL
-------
Private wells off of NAWC property in trie vicinity of Area B were not sampled during the Phase I Ri or
Phase II Rl. Available hydrogeotogic data suggest that contaminated groundwater attributable to Area
8 at the Site in overburden and shallow bedrock could potentially impact offsite wells. In response,
the Navy initiated an assessment of potential offsite impacts of groundwater associated with Area B
and surrounding NAWC property by sampling residential wells within Area 1 (see Groundwater Use
section) from April to July 1993. A summary of the results of this sampling effort for Area 2 appears in
Table 11. Significant VOC concentrations have been detected in the many of the wells sampled in the
area of Casey Village. Based on available information, the full nature and extent of offsite overburden,
shallow bedrock and deep bedrock groundwater contamination attributable to Area B cannot be
determined.
The quality of surface water in an offsite, unnamed tributary of Southampton Creek downgradient of
Area B has not been fully characterized at this time. To date, only two samples of surface water
downgradient of Area B have been collected. The analytical results for inorganics and organics in
these samples, as well as upgradient background samples, are summarized in Tables 12 and 13.
These preliminary results do not indicate elevated levels of metals in the tributary of concern.
VL SUMMARY OF STTE RISKS
This section summarizes available assessments of risk posed by contaminated groundwater
attributable to the Site in overburden and shallow bedrock aquifers to human health and the
environment These assessments are based on RI information generated to date.
A final assessment of risk presented by OU-1 wiO be included in the final Record of Decision for OU-1
to be issued after the full nature and extent of the groundwater contamination are identified.
Removal Actions by the Navy and EPA are addressing risks posed by residential well contamination
discussed in Section V.B.3. As a result, these risks are not being assessed as pan of this ROD.
A. HUMAN HEALTH
As part of the RI, a risk assessment was conducted with available data to estimate the potential risks
to human health posed by the contaminated groundwater in overburden and shallow bedrock
underlying Areas A and B.
The following exposure pathways were determined to present a potential risk to human health:
• Ingestion of the groundwater as a drinking water source.
• Dermal exposure to the groundwater (e.g., through handwashing, showering, and
bathing).
• Inhalation of contaminants in groundwater (la, volatile compounds emitted during
showering).
Potential human health risks were categorized as carcinogenic or noncarcinogenic. A hypothetical
carcinogenic risk increase from exposure should ideally fafl within a range of 1 X 10* (an increase of
one case of cancer for one mfflon people exposed) to 1 X10* (one additional case per 10,000 people
exposed). Noncarcinogenic risks were estimated utilizing Hazard Indices (HQ, where an Hi exceeding
one is considered an unacceptable health risk. Federal Maximum Contaminant Levels (MCLs) for
puttie drinking water supplies were also utilized to assess potential risks posed by exposure to
groundwater.
26
-------
TABLE 9
OCCURRENCE AND DISTRIBUTION OF SURFACE WATER INORGANICS NEAR SITES 1, 2, arid 3
NAWC. WARMINSTER, PENNSYLVANIA
Element
Barium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Sodium
Thallium
Zinc
CROL
200
6
10
25
100
3
5,000
15
40
5,000
10
20
Frequency of
P nailing fW«fitktn
(unflltared)
1/2
1/2
1/2
•
1/2
-
1/2
1/2
1/2
1/2
1/2
1/2
Upstream
Range of Positive
Detection
(unflltered)
80
21.200
3
-
69
-
8.520
39
12
8,020
2
32
RC*
(unflltered)
80
21.200
3
-
69
-
8.520
39
12
8.020
2
32
RC*
(filtered)
76
20.700
-
-
-
-•
8,350
39
-
7,990
-
-
Downstream
Frequency of
Positive
Detection
(unflltered)
1/2
1/2
-
1/2
2/2
2/2
1/2
2/2
1/2
1/2
-
1/2
Range of
Positive
Detection
(unflltered)
121
37,150
-
106
2.300
17
14.700
230-254.5
20
19150
-
99
RC*
(unflltered)
121
37.150
-
106
1.320-2.300
15.3-17
14.700
254
20
19.150
-
99
RC*
(filtered
134
43,050
-
-
-
-
16.950
272
13.8
22.430
-
74
*RC
CRDL
Representative concentration (for sample sets <5 RC » maximum positive concentration)
Contract Required Detection Limit
Adopted from • Halliburton NUS Corporation Rough Draft Ph«M II RaiMdiaJ Investigation Report. November 1992
27
-------
TABLE 10
OCCURRENCE AND DISTRIBUTION SURFACE WATER ORGANICS NEAR SITES 1, 2, and 3
NAWC, WARMINSTER, PENNSYLVANIA
(ug/L)
Compound
Bromomathane
1,1-Dfchloroalhana
Banzena
Dielhylphlhalae
Di-n-octyththatafe
Phananthrene
Fluoranfnena
Pyrana
Banz(a)anthracena
Chrysane
Benzo(b)fluoranthena
TIC*
CRQL
(lig/l)
10
6/10
fi/10
10
10
10
10
10
10
10
10
-
Fmqiwncy of
Poalttva Dataction
1/2
1/2
1/2
•
1/2
-
-
-
•
-
-
1/2
Upstraam
RangaofPosJUv*
Dataction
0.4
1
0.2
- •
0.2
•
-
.
•
-
-
+
Rapraaantatlva
Concantratlon
0.4
1
0.2
•
0.2
-
•
-
-
-
-
-
Downstream
Fraquancy of
Poaltlva Dataction
*
-
-
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
1/2
Ranga of Poaltlva
Dataction
.
-
-
0.2
0.1
0.1
0.3
0.3
0.1
0.2
0.2
+
Rapraaanti
Coneantrai
.
•-
-
0.2
0.1
0.1
0.3
0.3
0.1
0.2
0.2
-
TICa • Tantattoly identified compounds
CRQL - Contact Required Quantllation Urn*
Adopted torn • HaWburton NU8 CoipomHon Rouoli Omft PhM* II RwmdM lnv*MI0alion Raport. Nmwmlwr 1MB
-------
TABLE 11
OCCURRENCE AND DISTRIBUTION OF VOLATILE ORGANIC CONTAMINATION IN AREA 2
Chemical
Trichloroethene (TCE)
Tetrachtoroethene (PCE)
1,1-Dichloroethene (1.1-DCE)
1.1-OichJoroethane (1.1 -OCA)
1,1.1-TrichJoroethane (1.1,1-TCA)
1 . 1 ,2-Trichkxoethane (1.1 ,2-TCA)
cJs>1 ^-Oichloroethene (cis-1 ,2-OCE)
trans-1,2-Oichlofoetnene (trans-1,2-OCE)
1^-Oichlofoethane (1.2-OCA)
Carbon Tetrachloride (CCIJ
2-Butanone
TOTAL NUMBER OF WELLS SAMPLED IN AREA 2
CRQL
(ug/o
1 or 2
1 or2
1 or2
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
1 or 2
2 or 5
Frequency
of Positive
Detection
37
30
20
8
29
2
21
6
—
2
1
Range of
Positive
Detection (ugfl)
0.1 - 1200.0*
0.1 - 480.0*J
(c)
0.1 J • 19.0
02 J • 2.0
02 J - 35.0
0.2 J- 0.4 J
0.4 J. 530.0*
02 J • 3.0
6.9 - 8.7
0.7 L(c)
141 Wefls
J a Value is estimated because positive result is reported that is less than the
contract required quantitation 6miL
L(c) » Positive result is considered biased very low due to initial and continuing
caJbration resDonse factors less than 0.050.
CRQL
Resut taken from diution analysis.
Contract Required Quantitation Limit
Adopted from - HaOfcurtm NUS Cmponfen OrM
My and Swipfing AnaJyM, S«p»«nb«f 1992
29
-------
TABLE 12
OCCURRENCE AND DISTRIBUTION OF SURFACE WATER INORGANICS NEAR SITES 5, 6, AND 7
NAWC, WARMINSTER, PENNSYLVANIA
(ug/L)
Element
Barium
Calcium
lion
Magnesium
Manganese
Nickel
Potassium
Sodium
CRDL
200
6,000
100
6,000
16
40
5,000
6,000
Frequency of
Positive
Detection
(unaltered)
1/2
1/2
1/2
1/2
2/2
1/2
1/2
1/2
Midstream
Range of
Positive
Detection
(unflltered)
82
22,600
388
9,030
66-100
20
1,180
13,600
•
RC*
(unflltered)
92
22,600
388
9.030
100
20
1,180
13,600
RC*
(filtered)
90
23,000
-
8,550
49
-
-
12.100
Downstream
Frequency of
Positive
Detection
(unflltered)
1/2
1/2
1/2
1/2
1/2
•
1/2
1/2
Range of
Positive
Detection
(unflltered)
92
27,950
389
11,150
44
-
1.545
16.150
RC*
(unflltered)
92
27.950
389
11.150
44
-
1,545
16,150
RC*
(filtered)
83.5
26.800
-
9,845
24
-
-
7.680
RC*
CRDL
Representative Concentration (for sample sets <5. RC - maximum positive concentration).
Contract Required Detection Limit
Adopted from • Halliburton NUS Corporation Routfi Dmtt RUM II ftomedMl InvcXigation Rapprt. Novwnter 19S2
30
-------
TABLE 13
OCCURRENCE AND DISTRIBUTION OF SURFACE WATER ORGANICS NEAR SITES 5, 6, AND 7
NAWC, WARMINSTER, PENNSYLVANIA
(ug/L)
Element
Bte(2-«thylhexyl)ph1halate
Chlorofonn
Diethylphthalate
CRDL
10
10725
10
Midstream
Frequency of
Positive Detection
1/2
-
.
Range of Positive
Detection
1
.
-
RC'
1
-
-
Downstream
Frequency of
Positive Detection
.
1/2
1/2
Range of Positive
Detection
-
12
0.2
RC*
.
12
0.2
RC* • Representative Concentration (for sample sets <5. RC » maximum positive concentration).
CRDL » Contract Required Detection Limit
Adopted horn - Halliburton NUS Corporation Rough Draft HUM II Remedial Investigation Report. November 1892
31
-------
Carcinogenic and noncarcinogenJc risks posed by hypothetical exposure to contaminated
groundwater in overburden and shallow bedrock were estimated for adult residents, child residents
and adult employees. To assess these carcinogenic and noncarcinogenic risks, primary organic and
inorganic contaminants of concern were selected based on their occurrence and distribution, mobility.
persistence and toxicity.
An important component of the risk assessment process is the relationship between the intake of a
contaminant and the potential for adverse health effects resulting from that exposure. Dose-response
relationships provide a means by which potential human health impacts may be quantified. The dose-
response relationships for carcinogenic and noncarcinogenic effects are reference doses (RfDs) and
cancer slope factors (CSFs), respectively. The RfO is developed by EPA for chronic and/or
subchronic human exposure to hazardous chemicals and is usually expressed as a dose per unit
body weight per unit time (mg/kg/day). CSFs are applicable for estimating the lifetime probability of
developing cancer as a result of exposure to known or potential carcinogens, are generally reported in
units of 1/(mg/kg/day), and are derived through an assumed low-dosage linear relationship of
extrapolation from high to low dose-responses determined form animal studies. RfDs and CSFs used
to calculate estimated risks in this case are identified in the Rl.
The Phase II Rl Report contains a detailed risk assessment for contaminated groundwater attributable
to Area A and Area B at the Site in overburden and shallow bedrock. The assumptions utilized in
conducting this assessment are identified therein. These assumptions include exposure input
parameters which estimate the exposure of an individual to a contaminant over time. Exposure to the
representative contaminant concentrations identified in Tables 2. 3. and 4 in Section V.B. of this ROD
was assumed.
In conducting this risk assessment, it is acknowledged that there are uncertainties associated with the
evaluation of chemical toxicity and potential exposures. For example, uncertainties arise in the
derivation of RfDs and CSFs and estimation of exposure point concentrations.
Summarized below are the results of the risk assessment for contaminated groundwater in overburden
and shallow bedrock attributable to Area A and Area B.
1. Area A
Cumulative, total estimated risks to human health due to potential exposure to noncarcinogenic and
carcinogenic groundwater contaminants attributable to Area A at the Site in overburden and shallow
bedrock are summarized in Tables 14 and 15, respectively.
The total HI and carcinogenic risk for hypothetical exposure to this groundwater exceeds values of
one and 1 X 10"*, respectively. Primary contributors to the unacceptable noncarcinogenic risk are
arsenic, trichtorothene (TCE), tetrachkxoethene (PCE), carbon tetrachloride, manganese, cts-1.2-
dichkxoethene, tnaffium and barium. Primary contributors to unacceptable carcinogenic risk are vinyl
chloride, TCE, PCE, arsenic (unfikered water only). 1,1-dfchtoroethene, 1.2-tfchkxoethane. carbon
tetrachloride. and chloroform.
In addition, the average concentiatlcm of TCE and PCE in wefls within Area A are 469 ug/l and 128
ug/l, respectively, in excess of the MCL of 5 ug/l for both of these substances. MCLs have also been
exceeded for carbon tetrachloride, vinyl chloride, 1,2-oichloroethene. cadmium, manganese, nickel,
arsenic and barium in individual groundwater samples collected within Area A.
32
-------
TABLE 14
SUMMARY OF NONCARCWOGENIC RISKS - STIES 1, 2, AND 3
NAWC WARM1NSTER - GROUNOWATER (CURRENT)
Exposure Route
•tyjBJtfj^Wl
Dermal Contact
t^^— j«^^— .«»
•wiaiiBinn
Total Risk
Receptor
Adut Resident
a6Ei
&1EO
3.7E-2
<2E1
VMWJ HtKMUelK
a4Ei
aTEO
...
aaEi
Adul Employee
1JE1
ZOE-1
—
1JE1
i NUB Corporation. PhM* I RMMdW hwMli«tfien fhpoit. April 1983
33
-------
TABLE IS
SUMMARY OF CARCINOGENIC RISKS - SfTES 1, 2. AND 3
NAWC WARMINSTER - GRCXJNDWATER (CURRENT)
Exposure Route
(nojBstion
DennaJ Cortact
t^fc^fci^^t-fc— fc
•vtaaDon
Total Risk
Receptor
AdUl Resident
4.4E-4
4.6E-4
aes-s
&9E-4
CMd Resident
Z1E-4
1JE-4
—
a4E-«
Adut employee
1.3E4
1JE-5
...
1.4E-*
34
-------
2. Area B
Cumulative, total estimated risks to human health due to potential exposure to contaminated
groundwater attributable to Area B at the Site in overburden and shallow bedrock are summarized in
Tables 16 and 17.
The HI for hypothetical exposure to unfiltered groundwater in this case exceeds one due to elevated
levels of arsenic, barium, cadmium, and manganese, while the hypothetical carcinogenic risk
associated with this water exceeds 1 X 10"9 due to TCE, PCE. carbon tetrachloride, and arsenic.
In addition, concentrations of TCE in three shallow bedrock wells in Area B exceeded the MCL of 5
ug/l in groundwater samples collected during both the Phase I and II RIs.
a ENVIRONMENT
Available Rl data are inadequate to fully assess risk to the environment (e.g., risk to aquatic life in
surface water) posed by groundwater in overburden and shallow bedrock at Areas A and B.
A brief, preliminary assessment of environmental risk based on available Rl data follows below.
1. Area A
Surface water samples to date are limited to two sets of filtered and unfiltered samples from an
unnamed tributary of Little Neshaminy Creek. Maximum concentrations of iron, lead and copper in the
unfiltered samples exceeded Ambient Water Quality Criteria (AWQC) developed pursuant to the
Federal Clean Water Act for the protection of aquatic life (see 40 C.P.R. Part 131). The specific nature
of aquatic life in this tributary is unknown at this time. Available Rl data indicate this tributary acts as
a groundwater divide for the overburden aquifer in the vicinity of Area A (see Tables 9 and 10 for
sample analytical summary). These data suggest contaminated groundwater in overburden of Area A
could migrate to this tributary and potentially present an unacceptable risk to the aquatic fife. (A
preliminary assessment of hypothetical human health risk posed by this surface water using the
subject data does not indicate a potential noncarcinogenic or carcinogenic risk of concern to children
or adults.)
ZAreaB
Two sets of filtered and unStered samples of surface water collected to date in the vicinity of Area B
detected no contaminant levels of environmental (or human health) concern. The extent of
groundwater discharge from Area B to surface water in this area, if any, is unknown (see Tables 12
and 13 for sample analytical summary).
C. CONCLUSIONS
Contaminated groundwater attributable to Areas A and B at the Site in overburden and shallow
bedrock has been determined to present an unacceptable risk to human health and/or the
environment As indicated in Section V., this contaminated groundwater may migrate to offsite
drinking water supplies and/or surface water.
35
-------
TABLE 16
CURRENT GROUNDWATER NONCARONOGENJC INGESTON RJSKS TO
ADULT RESIDENTS - SITES 1, 2. and 3 - MODIFIED WTTH FILTERED INORGANICS
(POTENTIAL CURRENT EXPOSURE)
NAWC, WARMNSTER, PENNSYLVANIA
Exposure Route
Dermal Contact
Inhalation
Total Risk
ReoBptor
Adut Resident
1.2E1
1.1E-1
9.4E-*
1.2E1
Chid Resident
Z8E1
a3E-2
NA
Z8E1
Adut Employee
4.2EO
aoe-3
NA
4.EO
Adopted from • HiUbuton NUS Corpontfon PtaM I RvrndU Irw««fl8dlen Ftopoti April 1983
-------
TABLE 17
SUMMARY OF CARCINOGENIC RISKS - CURRENT GROUNOWATER
NAWC WARMINSTER - GROUNOWATER SITES 5, 6, AND 7
Exposure Route
Ingestion
Dermal Contact
innaianon
Total Risk
innnf^-^f^-
Kscepcor
Aduft Resident
7.4E-S
&6E-6
3.1 E-6
a4E-5
CHdReskfertt
ase-s
4.0E-7
NA
ase-s
AdutEn^toyee
2.2E-5
1.8E-7
NA
2^E-5
Adopted from - Htffeurton NU8 CMporabon PIMM I Ra
37
-------
Actual or threatened releases of hazardous substances from the Site, if not addressed by
implementing the interim remedial action selected in this ROD, may present an imminent and
substantial endangerment to public health or welfare, or the environment.
VL DESCRIPTION OF ALTERNATIVES
An FFS was conducted by the Navy to identify and evaluate remedial alternatives for contaminated
groundwater attributable to the Site in overburden and shallow bedrock aquifers. Applicable
engineering technologies for achieving the interim remedy objective of minimizing contaminant
migration were initially screened in the FFS based on effectiveness, imptementability, and cost The
alternatives meeting these criteria were then evaluated and compared to nine criteria required by
CERCLA. Three interim remedy alternatives were developed for OU-1. Costs and implementation
times were estimated for each alternative described in this section.
A, ALTERNATIVE 1: NO ACTION WTTH GROUNOWATER MONTTORING
The NCR requires that the "no action* alternative be evaluated at every Site to establish a baseline for
comparison with action alternatives. Under this alternative, no remedial action would be undertaken to
address contaminated groundwater attributable to the Site in overburden and shallow bedrock
aquifers. Instead, additional studies necessary to identify the fid nature and extent of contaminated
groundwater in overburden and shallow bedrock aquifers would be conducted as part of continuing
Rls addressing the Sfta In addition to these studies, monitoring of groundwater in overburden and
shallow bedrock aquifers would be conducted for an estimated 30 yean.
For cost estimation purposes, a total of 20 overburden and shaflow bedrock wefls would be sampled
quarterly for an estimated 30-year period. The frequency of samplng may be reduced after a reliable
trend has been established An estimated four additional weds would be installed in the downgradtent
areas. Because this alternative would result in contaminated groundwater remaining at the facility,
five-year reviews would be required to monitor the effectiveness of this alternative. The present worth
of this alternative is estimated to be $2,871,000 over a 30-year period, with a capital cost of $72,000
and an annual operation and maintenance (O&M) cost of $182,000.
The addftional monitoring weds could be instafled approximately three weeks after a field crew and
equipment are mobilized.
& ALTERNATE 2: GROUMWATER EXTRACT!^
SURFACE WATER
Under this alternative, contaminated groundwater in overburden and shaflow bedrock aquifer*
attributable to the SI* would be extracted using a series of extraction weOs. The extraction wel
network wouid be located as necessary to maximize the effectiveness of the system. The
groundwater would be pumped to an on-sfte treatment system constructed speciBcaBy to treat
groundwater. Water treatment would include air stripping to reniovo VOCs and carbon adsorption to
remove semivolatfle organic* (or other means, I necessary). Emissions from the air stripper would be
treated by vapor phase carbon adsorption as required by PA Code Chapter 127 and the National
Ambient Air Quaflty Standards for Hazardous Air Pollutants (NAAOS) and National Emissions
Standards for Hazardous Air Polutants (NESHAPS) under trie Federal Clean Air Act Metate in the
water would be treated by precipaatlon and Wration (or other means, I necessary). Organic and
inorganic treatment residuals would be disposed offsfte as required by treatment, storage and
disposal regulations under the Federal Resource Conservation and Recovery Act (RCRA), including
Land Disposal Restrictions (LDRs) under 40 C.F.R Parts 262 and 268, Pennsylvania Hazardous Waste
Management (25 PA Code, Article VII) and Residual Waste Regulation (25 PA Code, Article DQ. Upon
meeting effluent Emits consistent with National Pollution Discharge Elimination System (NPDES)
38
-------
requirements under the Federal dean Water Act and Pennsylvania dean Streams Law, the treated
water would be discharged to an unnamed tributary of Little Neshaminy Creek or an unnamed
tributary of Southampton Creek. Treatability studies would be performed to confirm that effluent levels
meet NPDES requirements.
Concurrent with the design, construction, and operation of the initial extraction wefl network and
treatment system, investigations would be conducted both on and off NAWC property as necessary to
fully identify the nature and extent of contamination in overburden and shallow bedrock aquifers
attributable to Areas A and B. If additional contamination is identified, the extraction weU network and
treatment system would be modified as necessary during the interim action for OU-1 to minimize
migration of contaminants and to maximize the effectiveness of the extraction well network.
This alternative would also incorporate the sampling of existing on-ste and off-site wefls. Monitoring of
groundwater in overburden and shallow bedrock aquifers would be conducted for an estimated 30
years.
To estimate the cost of this alternative, the following assumptions were made: a total of 25 extraction
weBs would be installed (16 within Area A and 9 within Area B); a total flow of 56 gallons per minute
(gpm) would be pumped to a plant constructed near Area A for treatment; and on-site and off-site
wells would be constructed and monitored on a quarterly basis for an estimated 30 years. (Additional
costs would be incurred if additional groundwater from overburden and shallow bedrock aquifers were
extracted and treated.) Based on these assumptions, the present worth of this alternative was
estimated at $13,172,000. with a capital cost of $3,515,000 and an operation and maintenance cost of
$628,000 annually. This alternative could be constructed in 12 months or less.
C. ALTERNATIVE 3: GROUNDWATER EXTRACHCtl ON-SfTE PRETREATMECT, AND 06CHARGE
TO NAWC WARMINSTER WASTEWATER TREATMENT PLANT OR PUBLICLY OWNED
TREATMENT WORKS
Under this alternative, contaminated groundwater in overburden and shadow bedrock aquifers
attributable to NAWC Warminster would be extracted using a series of extraction weUs. The extraction
weU network would be located as necessary to maximize the effectiveness of the system. The
extracted groundwater would be pumped to an on-site treatment system constructed specifically to
pretreat groundwater prior to discharge to the NAWC Warminster Wastewater Treatment Plant
(WWTP). in the event that the NAWC Warminster WWTP ceases operation as part of Base
Realignment and Closure, the pretraated groundwater would then be discharged to a pubOdy owned
troatmert works (POTW) such a» the WanninsterMunk^ The discharge of
procreated water to the POTW would comply with Federal Ctoan Water Act (33 U.S.C. Section 12S1 a
sea) pretreatment regulations as sat forth at 40 C.F.R. Part 403 and the pretreatment requirements of
the receiving POTW. Pretreatment may include air stripping to remove volatile orgartics,
predpttatton/fBtration (or other means, I necessary) to remove metats, and/or carbon adsorption to
treat semivolatfle organic*. Emissions from the air stripper would be treated by vapor phase carbon
adsorption as required by PA Code 127, NAAQS and NESHAPS. Organic and inorganic treatment
residuals would be dteposed offsfte and handled as required by treatment, storage and disposal
regulations of RCRA, inducing LDRs under 40 C.F.R. Part* 262 and 268,25 PA Code, Article VH and
25 PA Code, Article DC After pretreatment, the groundwater would be discharged to the NAWC
Warminster or POTW WWTP. Trestabffity studies would be conducted as necessary to confirm that
the pretreatment meets the requirements of the receiving WWTP.
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Concurrent with the design, construction, and operation of the initial extraction well network and
treatment system, investigations would be conducted both on and off current NAWC property as
necessary to fully identify the nature and extent of contamination in overburden and shallow bedrock
aquifers attributable to the Site. If additional contamination of concern attributable to NAWC is
identified, the extraction well network and treatment system would be modified as necessary during
the interim action for OU-1 to minimize migration of contaminants and to maximize the effectiveness of
the extraction weQ network.
This alternative would also incorporate the sampling of existing on-stte and off-site weds. Monitoring of
groundwater in overburden and shallow bedrock aquifers would be conducted for an estimated 30
years.
For cost estimation purposes, the potential cost of connecting to a POTW such as the WMA WWTP is
not included. The present worth of this alternative was estimated at $13,172.000 with a capital cost of
$3,515,000 and an operation and maintenance cost of $628,000 annually. This alternative could be
constructed in 12 months or less.
VOL COMPARATIVE ANALYSS OF ALTERNATIVES
To help select a remedial action, CERCLA requires that remedial alternatives be evaluated under the
nine criteria discussed below.
A. CA/BMLLPROTECTON OF HUMAN HEMTHATO
Alternatives 2 and 3 would protect both human health and the environment by minimizing the
migration of contaminated groundwater in overburden and shaflow bedrock aquifers. Additional
studies to determine the ful nature and extent of groundwater contamination attributable to the Site
would be conducted concurrently with the design, construction, and operation of the groundwater
0301 action and treatment system.
Alternative 1 would not meet the objective of minimizing the migration of groundwater contamination
attributable to the Site in overburden and shalow bedrock aquifers. Therefore, this alternative is not
considered protective of human health and the environment
a COMPUANCE WITH APPLICABLE OR RELEVANT AND APPflCfWATE REQUBEMENTS
(ARARs)
AFl^Rs tor both Atamative* 2 arid 3 are identified in oetaiwi^ These
alternatives would be equaBy effective in meeting these ARARs. Since no remedial action would be
taken under Atemative 1. there are no ARARs associated wth remetfal activity under this attemative.
Only ARARs atsodated with groundwater monitoring would apply and be met in this case.
C. LONG-TERM EFFECTIVENESS AND PERMANENCE
By initiating an interim action at this time, Aftevnatives 2 and 3 may reduce the tinie necessary to
restore affected aquifers relative to Atemative 1.
Alternatives 2 and 3 require groundwater monitoring to evaluate their effectiveness. Operation and
maintenance of the treatment plant and monitoring of the treated discharges would be required for
both erf these alternatives.
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D. REDUCTION OF TOMCTTY. MOBOJTY, OR VOLUME
Alternatives 2 and 3 would reduce the volume and toxicity of contaminated groundwater. Further
migration of groundwater in the overburden and shallow bedrock aquifers would be contained by the
extraction systems. The treatment systems for these alternatives would generate residuals that would
require further treatment or disposal
Alternative 1 would not use treatment to reduce the toxicity. mobility, or volume of contaminated
groundwater in overburden and shallow bedrock aquifers.
E SHORT-TERM EFFECTIVENESS
Under7Alternative 1, groundwater contaminants would continue to migrate and would present potential
unacceptable risks to human health. There would be no additional risks to the public or the
environment under Alternatives 2 and 3. In the case of these alternatives, workers would be required
to wear protective equipment during activities where they may be exposed to hazardous materials.
F. IMPLEMENTABOJTY
No remedial action is included under Alternative 1.
For Alternatives 2 and 3, the remedial technologies and process options proposed for groundwater
extraction and treatment all have been proven to be imptementaote and commercially available.
Treatability studies would be required for both alternatives to ensure that treatment requirements can
be met. In each case, if extraction wells were required off of NAWC property, access to the property
of concern would be required.
Under Alternative 2, it is reasonable to assume that extracted groundwater could be treated on site to
meet Federal and State NPDES requirements for discharge to a tributary of Little Neshaminy Creek or
Southampton Creek.
Under Alternative 3, it is reasonable to assume that extracted groundwater could be treated on site as
necessary to meet the pretreatrnent requirements of the NAWC Warminster WWTP. However, the
NAWC Warminster WWTP may cease operating within the next five years. The Warminster Municipal
Authority (WMA) is the only POTW within a reasonable distance of the NAWC. WMA has indicated
that the capacity of the WMA WWTP is not designed to handle the flow of pretreated water protected
in this case. As a result, the discharge of pretreated water to the WMA WWTP does not appear to be
implementable.
a COST
The present worth of Atemaflvel is $2,871,000. The present worth of Alternative 2 is $13,172,000.
The present worth of Atamative 3 is also $13,172.000.
K STATE ACCEPTANCE
The Commonwealth of Pennsylvania concurs with the selected interim remedy for OU-1 at this Site,
Alternative 2.
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L COMMUNITY ACCEPTANCE
A public meeting on the Proposed Plan was held on May 10,1993 in Warminster, Pennsylvania
Comments received orally at the public meeting and in writing during the public comment period are
referenced in the Responsiveness Summary (Section VULof this ROD). Comments from the local
community reflect a preference for Alternative 2: Groundwater Extraction, On-Site Treatment, and
Discharge to Surface Water.
X SFIFCTED REMEDY
A, GENEML DESCRIPTION
The Navy and EPA have selected Alternative 2: Groundwater Extraction, On-Site Treatment, and
Discharge to Surface Water as the interim remedy for remediation of contaminated groundwater
attributable to Areas A and B at the Site in overburden and shallow bedrock aquifers. This alternative
includes the design and implementation of an interim remedial action to protect human health and the
environment More specifically, this alternative meets the objective of minirnizing the migration of
contaminated groundwater attributable to the Site in overburden and shadow bedrock aquifers while
further Remedial Investigations are performed to determine the fun nature and extent of contamination
in these aquifers. The final remedy for OU-1 will be selected after the ful nature and extent of the
contamination are identified and wil utiBze information generated during the implementation of the
interim remedy. The final remedial action may incorporate elements of the interim remedial action.
The selected interim remedy is believed to provide the best balance of trade-offs among the
alternatives with respect to the response criteria. Based on available information, the Navy and EPA
befieve the selected interim remedy would be cost effective and would comply with applicable or
relevant and appropriate requirements. Atthough this interim action is not intended to fufly address
the statutory mandate for permanence and treatment to the maximum extent practicable, this interim
action utilizes treatment to reduce volume and toxkaty and thus is in furtherance of that statutory
mandate.
The selected interim remedy for OU-1 includes the toflowing major components:
• Installation, operation and maintenance of groundwater extraction wels to minimize
migration of contaminated groundwater attributable to Areas A and B at the Site in
overburden and shaflow bedrock <
Instafiation, operation and maintenance of an onstte groundwater treatment system
which Includes precipitation, Station, air stripping and carbon adsorption arid/or
'QUw necessary means of treatment
Pwtodfc sampfng of treated water to ensure the effectiveness of the treatment system
Discharge of treated water to an unnamed tributary of Uttie Neshaminy Creek or an
unnamed tributary of Southampton Creek
Installation, operation and maintenance of vapor phase carbon adsorption unfts as
necessary
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• Offsite treatment and/or disposal of solid residuals generated during water treatment
• Monitoring of groundwater in monitoring wells and residential wells
• Installation and periodic sampling of observation wells to ensure effectiveness of the
groundwater extraction wells
• Periodic evaluation of hydrogeoJogic data and the effectiveness of the groundwater
extraction system in minimizing the migration of contaminated groundwater attributable
to Areas A and B at the Site in overburden and shallow bedrock aquifers
• Modification of the groundwater extraction wed system and/or groundwater treatment
system as necessary based on periodic evaluations
The FFS estimated the present worth of thto remedy at $13,172.000 over a 30-year period, with a
capital cost of $3,515,000 and an annual O&M cost of $628,000.
Performance standards associated with the components above are described below.
ffiMANCE STANDARDS
1. Groundwater Extraction Web
The extraction well network win include extraction wefis in the vicinity of Area A and Area B. These
extraction weBs wff be installed on and off current NAWC property, as necessary, to minimize the
migration of contaminated groundwater in overburden and shallow bedrock underlying these areas,
where shaDow bedrock is currently defined to extend to a depth of 100 feet below the ground surface.
The migration of the contaminated groundwater wi be minimized by achieving and maintaining an
inward and upward hydraulc gradient about the extraction welts installed for each area. The FFS
projected that 16 extraction weds pumping at a depth of 87 feet and at a rate of 36 gpm would
minimize the migration of contaminated groundwater in the overburden and shallow bedrock in the
vicinity of Area A. The FFS projected that 9 extraction weBs pumping at a depth of 77 feet and a rate
of 20 gpm would minimize the migration of the contaminated groundwater of concern in the vicinity of
AreaB.
Observation weto wi be located and constructed to gather data to confirm these gradients and to
characterize the response of the aqutfer to pumping. This information, in conjunction wth addttonal
hydrogeotogic and contaminant Distribution data generated during concurrent M work wfl be used to
modify and optimize the extraction wet system for mMrrOzing rnigratlon of contaminated groundwater
in the overburden and shallow bedrock as necessary during this interim remedial action. Aloftne
resultant data, including information regarding the deeper bedrock aqutfera, wtt be used to confirm
the vertical and horizontal extent of the shaDow bedrock and determine the final extraction we!
configuration, the appropriate depths and pumping rates for the system the performance monftoring
program and the cleanup goals and timeframes anticipated for the final remedial action ROD for OU-1.
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The groundwater from each extraction wefl wiU be raised by a sutxnersible pump. An underground
header piping system win collect the extracted groundwater and convey the groundwater to a
treatment system located on current NAWC property. A booster pump station(s) will be used to help
convey the groundwater from the extraction wells to the treatment system as necessary.
As part of additional Rj work, monitoring wells will be installed on and off current NAWC property as
necessary to determine the full nature and extent of contaminated groundwater attributable to Areas A
and B in overburden and shallow bedrock. In any case where additional contaminated groundwater
attributable to Areas A and B is identified in overburden and/or shallow bedrock, the extraction wefl
network shall be modified as necessary to minimize the migration of the contaminated groundwater of
concern.
Treatment System
The treatment system for extracted groundwater wfll meet effluent limits developed in accordance with
National Pollution Discharge Elimination System (NPDES) requirements under the Federal Clean Water
Act, NPDES requirements under the Pennsylvania Clean Streams Law (25 PA Code, Chapter 92) and
Pennsylvania Wastewater Treatment Requirements (25 PA Code, Chapter 95). The receiving stream(s)
for the treated groundwater will be either an unnamed tributary of Utde Neshaminy Creek and/or an
unnamed tributary of Southamptkxi Creek. Where the seven-day, 10-year low flow of these projected
receiving streams is zero (due to intermittent flow), the effluent limits wfll be the Pennsylvania Water
Quality Standards (25 PA Code, Chapters 16 and 93) for the stream of concern since no diutton win
be provided by the receiving stream under low-flow conditions.
The treatment system win include precipitation, sedimentation and filtration as necessary to remove
metals, with air stripping and carbon adsorption as necessary to remove volatile and semivolatBe
organics. AJr stripping win remove volatile organics prior to carbon absorption to reduce carbon
usage. Ion exchange or reverse osmosis win be used » necessary to meet the effluent Imtetor
metals. Alternative treatment methods such as UV/oxkJatkxi rnay be reo^ired to remove organics if air
stripping and carbon adsorption are inadequate to meet organic effluent Brruts. TreatabiGty studies wifl
be conducted as necessary. The initial groundwater treatment system wfll be designed to handle
significant additional capacity beyond that required for the initial extraction wefl network to
accommodate additional potential flow in the future (see Groundwater Extraction Wefts). The treated
groundwater shall be monitored as necessary to assure that prescribed effluent limits are being met
prior to discharge. An Operation and Maintenance plan shall be developed and implemented to
assure the continued effective operation of the Groundwater Treatment System.
a Treatment of Air Emissions
Volatile organic compound emissions from the air stripper wi be treated by vapor-phase carbon
adsorption as required by 25 PA Code. Chapter 127, Subchapter A, a» wel as the National Emissions
Standards tor Hazardous Air PoOutants (NESHAPs) and the NatkwaJ Ambient Air (taaBy Standards for
Criteria Pollutants (NAAQS) under the Federal Clean Air Act EPA Directive 3355.0-28, which covers
emissions from air strippers at CERCLA sites, is a standard to be considered.
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4. Waste Treatment Residuals
Spent carbon from the carbon adsorption unit, spent carbon from the vapor-phase carbon adsorption
unit and sludge generated during the treatment of metals win be handled in accordance with
treatment, storage and disposal requirements under RCRA. including RCRA LORs in 40 C.F.R Parts
262 and 268, Pennsylvania Hazardous Waste Management Regulations (25 PA Code, Article VII) and
Residual Waste Regulations (25 PA Code, Article DQ.
& Groundwater Mentoring
An Operation and Maintenance Plan tor Groundwater Monitoring for groundwater in overburden and
shallow .bedrock shaD be developed and implemented. The Plan wiS be approved by the EPA in
consultation with PAOER Under the Plan, welts shaD be monitored at locations on and off current
NAWC property. Monitoring shal include residential and other privately owned wells as necessary.
Monitoring wells shall be installed off of current NAWC property as necessary. Monitoring win be
conducted through the selection and implementation of the final remedy for OU-1 and for at least thirty
years.
a Five Year Reviews
Because contaminated groundwater wffl Bcety remain at the facility after five years, a five year review
wfl be required. A Five-Year Review Work Plan wH be developed and approved by EPA in
consultation with PAOER
7. Worker Safety
All work shaD comply with Occupational Safety and Health Administration (OSHA) standards governing
worker safety in 29 C.F.R Parts 1910,1926 and 1904.
X STATUTORY DETERMINATIONS
A, PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
This interim action is protective of human heath or the environment by minimizing the migration of
groundwater contamination attributable to Area A and Area B at the Ste in overburden and shallow
bedrock aquifers. The ootoctod Interim remedy wB not pose unacceptable short-term risks to human
health and the envirorvnont during Imptemontfltkyi.
a COMPUANCEWimARARS
The selected Interim remedy wi comply wth al applicable or relevant and appropriate requirements
specific to this interim action. These ARARs Include those Identified In Section DC and those feted
below:
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1. Location-Specife ARARs
The substantive requirements of the Delaware River Basin Commission (18 C.F.R Part 430) are
applicable. These regulations establish requirements for the extraction of groundwater within the
Delaware River Basin.
Spedfic ARARs
Federal Clean Air Act requirements, 42 U.S.C. §§7401 et sea, are applicable and must be met for the
discharge of contaminants to the air. Pennsylvania's Air Pollution Control Act is also applicable, as
are Pennsylvania's Air Poflution Control Regulations (25 PA Code, Chapters 121-142).
The requirements of Subpart AA (Air Emission Standards tor Process Vents) of the Federal RCRA
regulations see forth at 40 C.F.R. Part 264 are relevant and appropriate and. (depending upon the
levels of organics in the extracted groundwater and treatment residuals) may be applicable to the air
stripping operations conducted as part of the selected interim remedy. These regulations require that
total organic emissions from the air stripping process vents must be less than 1.4 kg/hr (3 Ib/hr) and
2800 kg/yr (ai tons/yr).
25 PA Code, Section 123.31 is applicable to the selected remedial alternative and prohibits malodors
detectable beyond the NAWC property line.
25 PA Code. Section 127.12(a)(5) wOi apply to new point source air emissions that result from
implementation of the sotoctod interim remedy. These Commonwealth of Pennsylvania regulations
require that emissions be reduced to the minimum obtainable levels through the use of best available
technology CBAT*) as defined in 25 PA Code. Section 121.1.
The substantive requirements of 25 PA Code, Section 127.11 wi apply to the selected Interim remedy.
These Commonwealth of Pennsylvania regulations require a plan for approval for most air stripping
and sol ventinoydecontarnination projects designed to remove volatile contaminants from sofl, water,
and other materials.
Regulations concerning weB drilling as set forth in 25 PA Code, Chapter 107 are appOcabte. These
regulations are established pursuant to the Water WeB Drillers License Act, 32 P.S.S 645.1 etseo.
Only substantive requirements of these regulations need be fbOowed for onsfte actions.
The groundwater collection and treatment operations wiB constitute treatment of hazardous waste (La,
the groundwater containing hazardous waste), and wil result in the generation of hazardous wastes
derived from the treatment of the contaminated groundwater (Lei, spent carbon filters from carbon
adsorption treatment of water and from vapor-phase carbon adsorption treatment of air emissions
from air stripping operations). The interim remedy wl be implemented in a manner consistent wfth
the requirements of 25 PA Code, Chapter 262, Subpaits A (relating to hazardous waste determination
and identification numbers), B (relating to manifesting requirements for off-sfte shipments of spent
carbon or other hazardous wastes), and C (relating to pietranspurt requirements); 25 PA Code,
Chapter 263 (relating to transporters of hazardous wastes); and with respect to the operations at the
Sftec^neralV.wiUithesub8tanlh«reojuiremerttof2SPACod^
event that hazardous waste generated as part of the interim remedy is managed in containers) and 25
PA Code, Chapter 264, Subpart J (in the event that hazardous waste, is managed, treated or stored in
tanks). The interim remedy wi be also be implemented in a manner consistent with 40 C.F.R, Part
264, Subpart AA (relating to air emissions from process vents), 40 OF A Part 268, Subpart C, Section
268.30 and Subpart E (regarding prohibitions on land disposal and prohibitions on storage of
hazardous waste) and 40 C.F.R Part 264, Subpart AA (relating to air emission stands 3 for process
46
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vents).
25 PA Code. Chapter 264. Subchapter F, regarding groundwater monitoring is appicabte to the
selected interim remedy.
Any surface water discharge of treated effluent win comply with the substantive requirements of the
Section 402 of the Clean Water Act. 33 U.S.C. 91342, and the National Pollutant Discharge Elimination
System CNPDES*) discharge regulations set forth at 40 C.F.R. Parts 122-124, the Pennsylvania NPOES
regulations (25 PA Code, Section 9231), and the Pennsylvania Water Quality Standards (25 PA Code,
Sections 93.1-93.9).
The Occupational Safety and Health Act fOSHA1) regulations codffied at 29 C.F.R Section 1910.170
are applicable for afl activities conducted during this interim remedial action.
25 PA Code. Sections 261.24 and 271421 are applicable regulations for the handling of residual and
other waste and for the determination of hazardous waste by the Toxic Characteristic Leaching
Procedure (TCLP*)-
Transportation of any hazardous wastes off-site snal also comply with the Department of
Transportation CDOP) Rules for Hazardous Materials Transport (49 C.F.R. Parts 107 and 171-179).
a Standards To Be Considered
Pennsylvania's Ground Water Ouafity Protection Strategy, dated February 1992.
EPA Directive 9355.0-28, which covers emissions from air strippers at Superfund groundwater
remediation sites.
Pennsylvania Bureau of Air QuaOy Memorandum, "Air Quality Permitting Criteria for Remediation
Projects Involving Air Strippers and Sol Decontamination Units*.
EPA's Ground Water Protection Strategy, dated July 1991.
EPA OSWER Directive 9834.11 which prohibits the disposal of Superfund Sto waste at a factty not in
compliance with §3004 and §3005 of RCRA and an applicable State requirements.
C. COST-EFFECTTVENESS
The selected remedy is cost-effective in providing overafl protection in proportion to cost
0. inUZATONOFPCMIANENTSCXJUTOmANDALT^^
Oft leSOJRCE RECOVERY TEOMOIX>GES TO THE MAJQM^
Although this action is not intended to July address the statutory rnandate for permanence and
treatment to the maximum extent practicable, this interim action mazes treatment and thus is in
furtherance of that statutory mandate.
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E. PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
Because this action does not constitute the final remedy for Operable Unit One, the statutory
preference for remedies that employ treatment that reduces toxicity. mobility, or volume as a principal
element, although partially addressed by this remedy, will be addressed by the final response action.
XL DOCUMENTATION OF SIGNIFICANT CHANGES
The preferred alternative presented in the Proposed Plan was Alternative 3: Groundwater Extraction,
On-Site Pretreatment, and Discharge to NAWC Warminster Wastewater Treatment Plant or Publicly
Owned Treatment Works. Based on public comments, the selected remedy is Alternative 2:
Groundwater Extraction, On-Site Treatment and Discharge to Surface Water. The selected interim
remedy for OU-1 is as described in the FSS and the Proposed Plan with one exception. Rather than
address all contaminated groundwater attributable to the entire Site in overburden and shallow
bedrock aquifers as described in the FSS and Proposed Plan, the interim remedy for OU-1 shall only
address contaminated groundwater attributable to Areas A and B at the Site. Should additional Rl
work determine a remedial action is necessary to address groundwater in overburden and shallow
bedrock attributable to another area at the Site, a Proposed Plan for that action shall be released to
the public for comment prior to selecting a remedy.
XL RESPONSIVENESS SUMMARY
A. OVERVIEW
In a Proposed Plan released for pubfic comment on April 29,1993, the Navy, with the support of EPA,
identified Alternative 3 as the preferred interim remedial alternative for OU-1 at the Site. Alternative 3
in the Proposed Plan was as described in Section VIII. of this ROD.
The majority of written and oral comments received during the pubfic comment period were in support
of Alternative 2 as described in the Proposed Plan and Section VIII. of this ROD. Alternative 2 was
preferred by Warminster Township, the Warminster Municipal Authority, Coogresswoman Marjorie
Margoltes-Mezvinsky, the Bucks County NAWC Economic Adjustment Committee and the
Northampton Municipal Authority. Based on these and other comments received during the public
comment period, the Navy and EPA have selected Alternative 2 as the interim remedy for OU-1. Other
comments and the associated responses of the Navy and EPA are described below after a brief
discussion of community involvement to date
B. COMMUNITY MVOLVEMENT TO DATE
In July 1989, NAWC Warminster prepared a draft Community Relations Plan for RI/FS activities.
Osrnrnuniiy reiaflore activities to date have been conducted in accordance with this plaa These
activities have included regular Technical Review Ccmnittee rneetings with local officials.
communications with the media and the establishment of information repositories.
The Navy and EPA established a public comment period from April 281,1993 to May 28,1993 for
interested parties to comment on the Proposed Plan, the Rl Report, the FFS Report and other
documents pertaining to OU-1. These and at other documents considered or reled upon during the
interim remedy selection process for OU-1 are included in the Administiative Record, which has been
48
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in two information repositories accessible to the public since the beginning of the public comment
period for OU-1. A public meeting was held at Wiffiam Tennant High School. Centennial Road,
Warminster, Pennsylvania on May 10,1993 to present the Rl/FFS Reports and Proposed Plan, answer
questions, and accept both oral and written comments for the OU-1 interim remedy. Approximately
165 people attended this meeting..
This Responsiveness. Summary, required by CERCLA, provides a summary of citizens' comments
identified and received during the public comment period and the responses of the Navy and EPA to
those comments. AB comments received by the Navy and EPA during the public comment period
were considered by the Navy and EPA in sotocting the interim remedy for OU-1. Responses to these
comments are included in the section below.
SUMMARY OF COMMENTS RECEIVED DURING PUBUC COMMENT PEWOO AND COMMENT
RESPONSES
Comments received during the pubOc comment period regarding the interim remedy for OU-1 have
been summarized below with the responses of the Navy and EPA to these comments. The comments
and associated responses have been organized by subject category.
OnMi II ttt it II fc ii mi nit ri f^Mrfiimn 11 nnn
nonKKBaj Memauve nuwuices
Comment 1: A petition with 25 signatures, along with many written and verbal responses,
expressed a preference for Alternative 2, We/minster Township, the Warminster
Municipal Authority, Congresswoman Marjorie MargoBes-Mezvinsky, the Bucks County
NAWC Economic Adjustment Committee and the rJortharnpton Municipal Authority all
expressed a preference for Alternative 2. Several authorities/officials indicated
Alternative 3 should not be selected because existing local POTWs (ag., the POTW
owned by the Warminster Municipal Authority) did not have the capacity to handle the
volume of water expected to be generated by the OU-1 interim remedy.
Response: The Navy and EPA have selected Alternative 2 based on this and other comments
received during the pubic comment period
Comment 2: One commenter exp
i that Discharge to the NAWC WWTP wiO not be
Response;
feasible I the NAWC WWTP to not in compliance with an existing NPDES permit. Tnto
commenter also expressed concern that cost estimates in the FSS old not account for
the coat of medications to the NAWC WWTP which might be necessary prior to
accepting pretreated water.
The selected remedy does not include discharge to the NAWC WWTP. Therefore,
complance of the NAWC WWTP with NPDES requirements is not required to
inclement the selected remedy. Whfle the FFS old not estimate the cost of any
mooUcations to the NAWC WWTP es part of the evaluation of Atemative 3, this had
no bearing on the interim remedy selection process far OU-1.
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Comment 3: Some citizens expressed their preference for Alternative 3 because of their concerns
about the release of toxins to surface water. A petition with 11 signatures opposing
any discharge to surface water was filed by residents from the Twin Streams
development One commenter expressed a preference for land appication of pro-
treated groundwater as an alternative to stream discharge to protect stream users.
Response: Prior to any discharge of treated water to surface water, the quality of the water must
meet the requirements of the Federal Clean Water Act and the Pennsylvania Clean
Streams Law. According to these statutes, these requirements must be protective of
the uses of the receiving stream. Only water which meets these requirements and
thus is protective of all stream users, including children, wiB be released to surface
water. In addition, the location of the discharge shall be as necessary to be
• protective. Discharges wiB be monitored on a regular basis as necessary to assure
that the treated water is meeting the requirements.
Comment* Thirty-five residents of the Casey Village development submitted a petition stating that
the three alternatives discussed in the Proposed Plan were not acceptable because
they are, according to the petitioners, a threat to the health and wetfare of the
community. The residents requested that an alternate ctean-up solution be devised
under the supervision of EPA.
Response: The selected remedy wffl protect both human health and the environment by mooting
the objective of minimizing migration of contaminated groundwater in ovorburdon and
shalow bedrock aquters white studtes continue to identify the ful nature and extent of
contamination of these aquifers and other media The EPA beHeves the migration of
concern should be minimized at this time and that there are no other viable
aJtamatives for minimizing this migration.
*^*L^
ana
Comments: Several commenters were concerned about the possible quafty of discharges to
surface water. The comments centered around the following issues;
• What are the dbcharge irrdts and how would the discharge ftnto be
8017
• Who would enforce these Bmfcs and how would me Ante be enforced?
• ft^4^^« «*Mha J«i M •MM*^^W*^M^ rtawt r>r>^^ M«A^^ tfttA B«vt2ka4
now wouKi • ireaDneni process meet me Mimr
Response; The dbcharge Imte *• be set par NPOES requirements consistent with the
Penrnytvania Ctean Streams Law and the Federal Ctean Water Act The Pennsylvania
Depertmei* of ErNtronmertal Pasouroea, In cooperate
the dhcnaryimtearrtsuoseqtjentfy enforce ti^ dbcharge irrte. These imtewi
be eetebished during the design of the treatment plant as necessary technical data
are generated Compiance wtth the discharge ante wl be monitored by periodic
sampling consistent with NPOES requirements. In any case where the discharge Imte
are excoodod. the discharge would be halted and the treatment would be modfted so
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that any further discharge of effluent would meet the discharge Emits. Technologies
likely to be used for treatment of extracted groundwater include air stripping and
carbon adsorption for organics and precipitation for metals. If necessary, alternative
technologies such as UV/cabdation (for organics) and ton-exchange (for metals) may
be utilized. These technologies have been proven effective.
Comments: A number of commenters stated that the treatment process should incorporate
destructive technologies to destroy the contaminants. A concern was expressed
regarding the fate of carbon used in treatment and sludge generated during treatment.
Response: Organic contaminants in the extracted groundwater will adsorb to carbon during the
air stripping and water treatment process. The carbon will periodically be recycled by
transporting the •used* carbon to an offsite facility, where the adsorbed organic
contaminants wffl be destroyed by thermal treatment (or other means of treatment). If
utilized, UV/oxidation could also destroy the organic contaminants. No technology
exists to destroy metals, which wffl be accumulated in a sludge during treatment and
subsequently disposed at a permitted offsite facility.
Comment 7: A concern was expressed regarding the quafity of air emissions from the air stripper.
Response: Emissions from air strippers are regulated under both Pennsylvania and Federal law.
Section DCBA and Section XB. of this ROD identify the specific requirements of
concern.
*
Comments; During the public meeting, some local residents expressed concern that the extraction
we! network would dry out their weBs.
Response: As part of remedial design, the groundwater recovery wefl network wl be engineered
to avoid such imparts.
Comment 9: One commenter asked why only Areas A and B were being addressed by
investigations and the interim remedy for OU-1. Another commenter requested that
additional studes of groundwater in overburden and shaBow bedrock continue whfle
the interim remedy is implemented.
Response; Preliminary groundwater Investigations have been conducted at aB eight known
> as pan of n activity to date. At this time, adequate information exists to
: an interim remedy for Areas A and 8 (OU-1). RVFS work wi continue to
ddrae* other areas of the Sta Addttonal remedial actions wi be proposed and
! as soon as adequate information exists to support the ootoction of a remedy.
regard to OU-1, further Rl work is being performed to determine the ful nature
and extant of contaminated groundwater In overburden and shaflow bedrock
attributable to Areas A and B (OU-1).» addtanal groundwater contamination to
identified in overburden and shaflow bedrock in these areas, the groundwater pump
and treat system wl be mooHed as necessary to minimize the additional
contarninatton. A final Record of Decision for OU-1 *• be prepared when the Rl/FS
work for OU-1 is completed Per Section iae of the Federal Factty Agreement for
NAWC between the EPA and the Navy, the Rl/FS for OU-1 to not considered complete
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until a final remedy is selected
AddUonaJ Studtee
Comment 10;
Response:
Several residents expressed concern over the high incidence of cancer among
local residents.
This concern has been referred by the EPA to the Agency for Toxic
Substances and Disease Registry (ATSDR) for investigation.
Comment 11: Numerous residents fett that public water should be supplied to neighboring
communities near NAWC.
Response: Connections to public water systems are being provided by the EPA and the
Navy to residences in areas affected by groundwater contamination in the
vicinity of NAWC.
Comment 12: Several commenters expressed an objection to the lack of studies and a
remedy for the deep bedrock aquifer.
Response: At this time, there Is insufficient information to select a remedial aRernative for
groundwater in the deep bedrock aquier. The next phase of the RI/FS wi
study the deep bedrock aquBer (as wen as other media such as surface water,
sediment, and soils) to determine where additional remedial actions are
necessary.
Comment 13; Several residents, including 11 that signed a petition, expressed concern over
their property values. One resident wanted the Navy to purchase their home.
Response; Wnto property values may be impacted in certain cases at this time, these
values should be restored upon implementing the necessary response actions.
Comment 14:
A number of local residents qt
i to be used for
i dteposal in the past (stee 1 through 8) were ctil releasing contamination
or whether ongoing practices at NAWC were contributing to groundwater
fWJiMJl iJOf
Current data does not incfcate any significant ongoing contaminant releases
to groundwater from wastes disposed at steel through a In the event future
Rl work identifies a release of concern from • dhpoaal pros, response actions
snaf be taken as necessary. The handBng of waste generated at this time is
strictly regulated by the Federal Resource Conservation and Recovery Act
(RCRA) and Pennsylvania regulations.
Comment 1& Oevoral residents expressed concern about stormwater or groundwater
potentiafly contaminated by the Sto being discharged by culvert or storm
sewer to the* properties.
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Response; Additional R> work wB investigate afl potential water Discharges of concern
from NAWC to neighboring properties. Should contaminated groundwater in
overburden and shaDow bedrock attributable to the Site be determined to be
discharging to the surface of a neighboring property, the interim remedy for
OU-1 shall include minimizing the migration of the contaminated groundwater
of concern. Should additional RJ work determine the quality of stormwater
from NAWC is impacting (or could potentiaty impact) neighboring property, an
appropriate response action Shan be performed.
Comment 16; One resident expressed concern regarding the "orange seeps* observed
during RJ work to be discharging to an unnamed tributary of Little Neshaminy
Creek adjacent to Area A.
Response; Available data on the quality of this stream suggest that contaminated
groundwater in overburden under Area A may be discharging to this stream.
The interim remedy for OU-1 shai be designed as necessary to minimize any
contaminant migration to this stream. In addtton, the water and sediment in
this stream shaH be investigated further as necessary as part of continuing
RI/FSwortt
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