PB94-964006
EPA/ROD/R04-94/172
July 1994
EPA Superfund
Record of Decision:
Piper Aircraft Corp. Site,
Vero Beach, FL
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RECORD OF DECISION
FOR THE
PIPER AIRCRAFT CORPORATION SITE
THE DECLARATION
SITE NAME AND LOCATION
Piper Aircraft Corporation Site
Vero Beach, Florida
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Piper Aircraft Site, in Vero Beach, Florida, chosen in
accordance with the Comprehensive Environmental Response
Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 SARA 42 U.S.C.
Section 9601 et.seq. and, to the extent practicable, the National
Oil and Hazardous Substance Pollution Contingency Plan (NCP). This
decision is based on the administrative record for this site.
The State of Florida, as represented by the Florida Department of
Environmental Protection (FDEP), has been the support agency during
the Remedial Investigation and Feasibility Study process for the
Piper Aircraft Corporation site. In accordance with 40 CFR
300.430, as the support agency, FDEP has provided EPA with input
during the process~ Based upon comments received from FDEP, it is
expected that written concurrence will be forthcoming; however, a
letter formally recommending concurrence of the remedy has not yet
been received.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from
this site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
This remedy addresses the contaminated ground water at the
site. This remedy addresses the principal threat remaining at the
site by extraction and treatment of groundwater contaminated with
volatile organic compounds (VOC~). Ground water remediation will
continue until the aquifer meets the clean-up goals identified in
the ROD and monitoring up-gradient of the canal confirms that
ground water discharge to the canal meets surface water standards
for site related contaminants. Residuals from the treatment that
may have low levels of contaminants will be disposed of off-site,
such that the site will not require any long-term management.
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The major components of the selected remedy include:
Air stripping of VOCs to meet surface water discharge
criteria
Existing water line and extraction well used to the
extent practical
Installation of additional extraction
effectively capture entire plume
wells
to
Surface discharge of treated ground water in " accordance
with all applicable state and federal regulations and
other required Performance Standards
Modeling of air emissions and/or analysis of actual air
emissions from the ground water treatment unit will be
conducted during the Remedial Design and/or Remedial
Action in order to determine the need for air emission
control equipment to assure compliance with state and
federal air quality standards.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
legally applicable or relevant and appropriate to the remedial"
action, and is cost-effective. This remedy utilizes" permanent
solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable and satisfies the
statutory preference for remedies that employ treatment that reduce
toxicity, mobility, or volume as a principal element.
Because this remedy will result in hazardous substances remaining
on-site, a review will be conducted within five years after
commencement of the remedial action to ensure that the remedy
continues to provide adequate protection of human health and the
environment. These reviews will be conducted every five years or
until remediation goals are achieved. ""
~tY}7~
PATRICK M. TOBIN,
ACTING REGIONAL ADMINISTRATOR
IZ- 2:S-9.3
DATE
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1-'-
RECORD OF DECISION
FOR THE
PIPER AIRCRAFT CORPORATION
SUPERFUND SITE
VERO BEACH, FLORIDA
REGION IV
U.S. ENVIRONMENTAL PROTECTION AGENCY
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TABLE OF CONTENTS
Section
1.0 Site Location and Description
2.0 Site History and Enforcement Activities
3.0 History of Community Participation
4.0 Scope and Role of Response Action
5.0 Summary of Site Characteristics
5 . 1 Geology
5.2 Hydrology
5.3 Nature and Extent of Contamination
5.3.1 Soil Contamination
5.3.2 Ground Water Contamination
5.3.3 Surface Water and Sediment Investigation
5.3.4 Air Investigation
6.0 Summary of Site Risks
6.1 Contaminants of Concern
6.2 Exposure Assessment
6.3 Toxicity Assessment
6.4 Risk Characterization
6.5 Environment Risk
6.6 Uncertainties
7.0 Description of Alternatives
7.1 Alternative GW 1 No Action
7.2 Alternative GW 2 Ground Water Use Restrictions
7.3 Alternative GW 3 Ex-Situ Treatment
7.3.1 Alternative GW 3a Ex-Situ Treatment;
Surface Discharge
7.3.2 Alternative GW 3b
Gradient Control;
7.4 Alternative GW 4 In-Situ
7.4.1 Alternative GW 4a
Injection Well
7.4.2 Alternative GW 4b In-Situ Treatment;
Gradient Control; Ex-Situ Treatment;
Injection Well Disposal
8.0 Comparative Analysis of Alternatives
8.1 Comparative Analysis of Human Health and the
Environment
8.2 Synopsis of Comparative Analysis of Alternative
9.0 Selected Remedy
A. Ground Water Remediation
A.l Components of Ground Water Remediation for
Implementation
A.2 Extraction, Treatment, and Discharge of
Contaminated Ground Water
A.3 Performance Standards
a. Extraction Standards
b. Treatment/Discharge Standards
c. Design Standards
Compliance Testing
Ex-Situ Treatment;
Injection Well Disposal
Treatment (Bioremedial)
In-Situ Treatment;
B.
i-I
Paqe
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4
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5
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10
14
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29
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TABLE OF CONTENT (continued)
Section
10.0 Statutory Determinations
10.1 Protection of Human Health and the Environment
10.2 Compliance with ARARs
10.3 Cost-Effectiveness
10.4 Use of Permanent Solutions and Treatment
Technologies
10.5 Preference for Treatment as a Principal Element
11.0 Documentation of Significant Changes
i-2
Paqe
40
40
40
41
41
41
41
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FIGURES
Fiaures
Figure 1
Figure 2
Figure 3
Figure 4
Paae
2
8
11
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TABLES
Tables
Table 1
Table 2
Table 3
Table 4a
Table 4b
Table 5
Table 6
Table 7
Table 8
Table 9
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RECORD OF DECISION
The Decision Summary
Piper Aircraft Corporation
Vero Beach, Florida
Site
1.0
Site Location and Description
Piper Aircraft Corporation (PAC or Piper) is an active
facility located at 2926 Piper Drive, and occupies approximately
eight acres at the Vero Beach Municipal Airport. The facility is
located at - the intersection of Aviation Boulevard and Piper
Drive. (See Figure 1)
The site and surrounding area is relatively flat with surface
water removal capabilities which include natural and man-made
conveyances. The soil is not conductive to ponding.The man-made
conveyances (i.e., ditch/channel/canal system) are designed such
that no water remains standing in any of the areas for very long
after a rain event. The PAC facility is bordered to the north and
east by the municipal airport, to the west by undeveloped property,
and to the south by the Main Relief Canal (Canal). A residential
area is located less than a half mile south of the Canal. The
genera~ area surrounding the site is agricultural, commercial, and
residential.
The facility has large'buildings with concrete floors, paved
parking and driving areas, and storm drain systems. There is very
little topographic relief across the site. Overland flow for storm
water runoff on the west side of the facility is towards a ditch
(west ditch) located approximately 75 feet west of the
dewatering/extraction well (site). The ditch services a network of
drains from the parking lots and the loading/receiving area. Water
from the ditch flows south to the Canal, east to the Indian River,
and continues east to empty into the Atlantic Ocean. (See Figure 1)
The main facility is fenced with access gates located
throughout. The ground surface in the immediate vicinity of the
dewatering well is covered with asphalt and/or concrete, with the
exception of the drainage ditch, a grassy area to the north, and a
small grassy area located along the western fence.
2.0 Site Historv and Enforcement Activities
The PAC facility used trichloroethylene (TCE), which was
stored in an underground storage tank, in the assembly process of
airplanes and component parts. In October 1978, testing of the
Vero Beach City water supply (well head #15), revealed TCE
contamination. The samples of shallow ground water adjacent to the
storage tank revealed a TCE concentration of 39,000 parts per
billion (ppb). The City immediatley secured the well and following
an investigation, the TeE was tracked to an underground storage
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FIGURE 1
SITE LOCATION MAP
PIPER AIRCRAFT
VERO BEACH, FLORIDA
APPROXIMATE SCALE
1200 0 600 1800
< IN FCET )
I inch = 1800 ft.
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system at Piper. Piper promptly removed the TCE from the tank. The
tank was tested, found to be tight, and an additional
investigations revealed a leak in the underground piping system.at
the top of the tank connection. Piper installed well points in the
tank area with test results yielding confirmation of TCE
contamination. The tank had been in place approximately three
years, but the volume of the spill was undetermined since the
duration and leak rate was unknown.
In March 1979, the City of Vero Beach along with Piper
Aircraft hired a contactor who recommended a better discharge rate
for dewatering the area, stop withdrawal from well #15 completely,
and the installation of a new well and a discharge header at
spillway in the main relief canal. Based on these recommendations
the City of Vero Beach and PAC applied for a National Pollutant
Discharge Elimination System (NPDES) Permit from EPA to authorize
the discharge of effluent into surface waters/main relief canal.
EPA deferred the permit pending collection of a baseline survey of
TCE levels in the water, sediment and aquatic life in the main
relief canal and the adjacent portion of the Indian River.
In late 1980 a six inch dewatering well was installed adjacent
to the area where the underground storage tank had been removed to
a depth of approximately 50f~et below land surface (bls)
In 1981, Piper signed a consent agreement with the Florida
Department Environmental Protection (FDEP), formerly Florida
Department Environmental Regulation (FDER), which authorized them
to remediate the site. Piper began pumping ground water to the
spray headers located above the main relief canal to reduce
contaminant levels of TCE.
Piper, with oversight provided by FDER, began pumping at a
rate of approximately- 225 gallons per minute from the dewatering
well. This system is still in operation today. Water is piped
through a buried polyvinyl chloride (PVC) pipe to a discharge point
located approximately one mile east of the site. The contaminated
ground water is sprayed into the air to enhance the removal of
volatile organic compounds (VOCs).
In 1985 EPA began to evaluate the site for the National
priorities List (NPL). Piper received a score of 31.13, which was
high enough for EPA to propose the site for inclusion on the NPL.
In June 1989, Piper continued the remediation process, which
was over-seen by FDER, by removing the underground storage tank and
the soil to a level of 14' feet deep by 40' wide by 100' long,
aerated the soil to -remove the TCE, tested and returned the treated
soil to the site.
..-.'The PAC facility was added to the NPL on February ;1.6,..--1990,
due to the presence of ground water contamination. In October of
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1991, EPA mailed a special notice letter to Piper Aircraft
Corporation notifing them of the potential liability and necessary
investigative activities at the site. Piper expressed an interest
in conducting the Remedial Investigation (RI) with EPA's oversight,
however, Piper later informed EPA that they would not be able to
pay for the RI due to bankruptcy proceedings. Following Piper's
annoucment of inability to fund the RI, EPA began procedures to
aquire Superfund monies to pay for the investigation. On August 3,
1992, EPA began field work at the PAC site, to investigate the
nature and extent of contamination. The Final RI report indicates
that ground water beneath the site is contaminated with
trichloroethene [trichloroethylene] (TeE) and it's degradation
products and air quality in the immediate vicinity of the existing
ground water treatment system may also have been impacted. The
degradation products of TCE include 1,1-dichloroethene [1,1-
dichloroethlene], cis-1,2-dichloroethene, trans-1,2-dichloroethene,
and vinyl chloride.
3.0 History of Community Participation
In June of 1991, EPA started its community relation efforts by
conduGting community interviews and holding a public meeting at the
Vero Beach City Hall. The meeting was held to address concerns
expressed by the citizens and ~nform them of EPA's planned Remedial
Investigation activities. Thls meeting was attended by thirty-five
citizens of Vero Beach and representatives from FDEP.
A public comment period for the proposed remedial action was
held from September 29, 1993 through October 30, 1993. During this
time a Proposed Plan fact sheet was released to the public in order
to inform the public of EPA's findings and notifing the public that
they could review details of the RIfFS reports at the Indian River
County Main Library. In addition, a public meeting was held on
October 20, 1993. In the course of this meeting, EPA and the FDEP
answered questions about problems at the site and the remedial
al ternati ves under consideration. A response to the comments
received during this period is included in the Responsiveness
Summary, which is part of this Record of Decision (ROD). This
decision document presents the selected remedial action for the PAC
Site, in Vero Beach, Florida, chosen in accordance with CERCLA, as
amended by SARA, and to the extent practicable, the National
Contingency Plan. The decision for this site is based on the
Administrative Record.
4.0
SCOPE AND ROLE OF RESPONSE ACTION
This ROD discloses the planned remedial activities at the
site. The cleanup remedy will address the ground water
contaminants which remain at the site. The function of this remedy
is to reduce the risks associated with exposure to contaminated
groUrid water and to protect the surficial aquifer syste~ present
beneath the site. The ROD is the only ROD anticipated for this
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site since the contamination present at this site will be addressed
as a single operable unit.
5.0 Summary of Site Characteristics
The ground surface in the immediate vicinity of the dewatering
well is covered with concrete, with the exception of the drainage
ditch, a grassy area to the north, and a small grassy area located
along the western fence. The facility uses storm drains to remove
water from the parking and receiving areas. These drains empty
into the drainage ditch which flows south into the Canal. The
canal flows east into the Indian River and eventually to the
Atlantic Ocean.
5.1
Geology
Indian River County is underlain by a thick sequence of marine
limestone, dolomite, shale, sand, and anhydrite, ranging in total
thickness from about 5,500 to 12,000 feet. These formations
collectively dip slightly southeastward. In order of increasing
age, the main formations of interest underlying the area are
described below. The youngest formation present is the Anastasia
Formation. It is present along the coast and grades inland into
the Fort Thompson Formation. The Anastasia Formation is
Pleistocene in age. It consists primarily of tan to buff
consolidated beds of calcium carbonate-cemented sandstone (cemented
sand) and coquina (cemented shell fragments). It varies in
thickness from 100 to 150 feet.
Below the Anastasia Formation are the undifferentiated
deposits of the upper Miocene. These deposits are comprised of
shell, sandy clay, some zones being more cemented than others, and
is generally 50 to 125 feet in thickness. Below these deposits are
the Miocene-age Hawthorn Formation, a major regional deposit
characterized primarily by a predominance of clay. It
characteristically contains a distinctive green and brown clay.and
is up to 200 feet thick.
Beneath the Miocene deposits is a sequence of Oligocene and
Eocene Limestones. The combined thickness of these formations may
approach 1000 feet.
The site is underlain by approximately 100 feet of mixed sands
and shell beds, followed by another 25 feet of mixed sands, shell
and clay, followed by at least 25 feet of predominantly clay of a
dark olive green color.
The stratigraphy for the area of investigation can be best
described based on an evaluation of boring logs completed during
drilling at the three temporary well locations. Within the upper
eighty feet, five distinct stratigraphic zones were iden~i~~d.
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These are described below:
Zone 1 - Generally thin zone (maximum 5 feet thickness) . of
interbedded light to dark colored fine to medium grained sands
containing some orange brown streaks.
Zone 2 - Fairly uniform fine grained sand with dark brown
organic material and some ci.ay encountered at one boring.
Zone 2 also has a maximum thickness of about 5 feet.
Zone 3 - Generally light tan to medium gray colored fine
grained sand. Occasional white streaks and some clay present.
Thickness averages about 15 feet. Ground water encountered in
this zone at all borings, ranging in depth from 10 feet bls,
at borings TW-01 and TW-03, to about 18 feet in boring ,TW-02.
Zone 4 - Very uniform dark gray/dark brown fine to medium
grained sand. Extremely variable in thickness, ranging from
3 feet to 20 feet in thickness.
Zone 5 - Medium to dark gray/brown fine to medium grained sand
with varying amounts of shell fragments. Locally the amount
of shell fragments may be so great as to approach a coquina-
like texture. Color within this unit may also vary, with
occasional minor light .colored (tan, golden brown) units.
Zone 5 was not completely penetrated during boring, but
appears to be at least 40 feet thick in the vicinity.
5.2
Hydrology
The formations and deposits found within the Anastasia
Formation form the framework for the uppermost aquifer in the
region. This aquifer is referred to as the surficial aquifer
system. Well yields in the eastern part of the county may approach
250 to 1,000 gallons per minute. Ground water movement in the
shallow aquifer system is generally to the southeast with localized
influences created by pumping of the aquifer.
Located beneath the surficial aquifer system in Indian River
County is a major regional confining unit comprised of the
previously described Miocene deposits. Due to its thickness (on
the order of several hundred feet) and its lithology (primarily
clays) it is considered to be generally impermeable with poor water
yield. It is generally found at a depth of approximately 125 feet
in the eastern part of the county.
The major regional aquifer, the Floridan aquifer, is located
beneath the regional confining unit. It is made up of all of the
Oligocene and Eocene limestones beneath the Hawthorn and although
water yields may vary from one formation to the next, the Floridan
is generally considered to be, in total, a prolific aquifer~nd is
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capable of supplying millions of gallons of water per day to well
fields.
5.3
Nature and Extent of Contamination
Sampling conducted during the remedial investigation at the
site indicates the primary contaminated media is ground water which
contains trichloroethene (trichloroethylene), as well as, its
associated degradation compounds including: l,l-dichloroethene
(l,l-dichloroethylene), cis-1,2-dichloroethene, trans-1,2-
. dichloroethene, and vinyl chloride.
Migration appears to be limited to the south and southeast of
the Piper Aircraft facility. No contaminatlon was detected south
of the main relief canal. Monitor well 15.2, located approximately
1,000 feet due east of the water tank, appears to be at or near the
eastern edge of the plume. The estimated aerial extent of the
contaminant plume extends from the drainage ditch to the west, the
main relief canal to the south, and a line 50 feet north of the
extraction well which runs east from the drainage ditch until it
intersects the main relief canal.
5.3.1' Soil Contamination
Surface soil (SS) samples were collected during Phase I to
confirm the success of the 1989 soil treatment by PAC. A
background grab sample was collected northwest of the site to
establish a control. A composite sample was collected from the
area where the excavated soil was aerated (see Figure 2) .
As shown on Table 1, on-site levels of inorganics are
comparable to the background; however, chlordane and its
degradation products were detected in the composite sample. The
chlordane and heptachlor compounds share a common association.
Chlordane was once combined with heptachlor to produce a product
that was sold under the name Termide@. Because of their wide-
spread use, the presence of the parent compounds (chlordane and
heptachlor) and their associated degradation product compounds
(alpha-chlordane, cis-nonachlor, garna chlordane, and trans-
nonachlor a.long with heptachlor epoxide, respectively) are believed
to be are attributable to application of and subsequent degradation
of insecticides applied for termite control and not leakage from
the underground tank.
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v
00
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~EPA
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TABLE 1
SURFACE SOIL SAMPLE ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH, FLORIDA
AUGUST 1992
PA-01-SS PA-01-SSC
BCKGRND TREATMENT
PESTICIDE/PCB COMPOUNDS j.I.g/kg J.lCJ/kg
ALPHA-Cm..ORDANE /2 NA 96
CIS-NONACm..OR /2 NA 40
GAMMA-Cm..ORDANE /2 NA 89
TRANS-NONACm..OR /2 NA 130
total Chlordane 355
HEPTACm..OR NA 3.6J
HEPTACHLOR EPOXIDE NA 8.4J
INORGANIC ELEMENTS mg/kg mg/kg
ALUMINUM 1400 890
ARSENIC 1.3 0.8
BARIUM 2.4
CALCIUM 160000 1800
CHROMIUM 2.0
COPPER 9.0
IRON 1400 430
LEAD 5.9 2.7
MAGNESIUM 940 54
MANGANESE 21 8.3
MERCURY 0.06 0.06
SODIUM 1600
STRONTIUM 660 10
TITANIUM 54 82
VANADIUM 1.3
ZINC 3.9
FOOTNOTES:
NA - NOT ANAL'YZED - The composite surface soil sample was selected and submitted for Pesticide
Analysis
J - ESTIMATED VALUE .
N - PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
- - MATERIAL WAS ANAL'YZED FOR BUT NOT DETECTED
12 '~-CONSTITUENTS OR METABOLITES OF TECHNICAL CHLORDANE
.... ~-~
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5.3.2 Ground Water Contamination
Ground water flow was determined to be southeast and locally
influenced by the pumping of the on-site dewatering/extraction well
and city well #15.
Thirty-four ground water samples were collected during the
three phases of the RI (see Figure 3 - Ground Water Sampling
Location). During all phases of the RI, the greatest concentration
of VOCs were detected in the on-site extraction well. Sampling
results are provided in Table 2~'
Four VOCs typically associated wi th aviation fuels were
detected in the sample collect~d from the extraction well. Ethyl
benzene, o-xylene, (m- and/or p-) xylene, and toluene were detected.
at low concentrations that were estimated to range from 4.1 ~/l to
8.8 ~/l. All these values are less than the maximum contaminant
levels (MCLs).
TCE and two of its degradation products, trans 1,2-
dichloroethene and cis-1,2-dichloroethene, were detected on-site in
the extraction well and MW-02. Higher concentrations of TCE (300
~/l .decreasing to 50 ~/l) and cis-1,2-dichloroethene were
detected in shallow monitoring well, MW-02 during Phase II and III,
respectively. These levels exceeded Federal MCLs of 5.0 ~/l TCE
and 70 ~/l (cis-1,2-dichloroethene).
Cis-I,2-dichloroethene was also detected south, southeast, and
west of the site in municipal wells MW #15, municipal monitor
wells, MW #15.4 and MW #15.2 (at approximately 100 ft bls), and in
two temporary monitor wells, TW-06 and TW-02 (at approximately 80
ft bls). The highest levels of cis-1,2-DCE were detected in MW
#15. The levels were above (76 ~/l - Phase I) and below (68A ~/l
-Phase II) the MCL of 70 ~/l. Note that MW #15 has been returned
to pumping status by the Vero Beach Water and Sewer Department and
is continuously pumped and the contaminants are removed via an air
stripper as part of the municipal water system for Vero Beach. The
well is located south/southeast of the site. As for the
concentrations detected in temporary wells TW-06 and TW-02, they
were very low, less than 3 ~/l. Furthermore, considering ground
water flow direction is to the southeast, the source for the cis-
1,2-DCE detected in TW-02 is more likely from an unrelated plume
located west of the site. (The forementioned plume is located at
the Stump Dump site, which is northwest of the PAC site and is
unrelated because of the southe~stern ground water flow.)
Trans-1,2-DCE exhibited similar characteristics to cis-1, 2-DCE
in that it was detected in both on-site wells, EXT-WELL and MW-02,
and to the south, ~ri #15, and southeast, TW-06 (80 ft bls).
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\ / / .'--.-- -, ''-'----,- J "'-----"--' FIGURE 3
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) // <::::-'--' '-'--.,- \ AN U 1,[ SU LTS
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VIH" "0..../::>" y/ .
"- '91' ..1' . ..1' ~\... / ;;/
~ r;:.---==:--:'- "...HS-I,l-OICt-CIORO[IHLN( 1.1, --. -- ...\"C\C ...-~\( / -- . - --
'q' [][ co,-, I-11OCI'IOllOIIH,o' "" "J \.1>," -, \ ---
/!-;~T':'--'-------"-~~--'f!..~:;Ji;.~-;fl. . ._---:!];;~:>] \.,\ APPROXIMATE SCALE'
,,,,,,;~/)) ...;#W~ .'-.-........-.~~_..../ \ \ 661 n m (,6'
--:/", /,/ ~.~~:::'~' MW-15..3 f~> ,'" / ~ ~ I I
. ..-' ..- ~..#:...." .. ,,~.~ ..'''''''' '., u _. . -
---"::--- , .....,;:. - ...-#'" ,..-,.,: .' -.'- ."."./ ~'_.m.. .... ..
1.."-- ..-:.:::::::;::>-- ~;p~ .." ":<::'."') -"::':::-" Ii /;:;\ -_. -..... (II~ f[[l :-
/:::>:..,/ "'f~~ /<..~:...>' . "::::::----;? ~:/ 1 ;nch ' 667 rt.
J:"\ - ,/ -~' ".,'.".... -. ... >- )."" "// r"~--"--h"'-"--".--]1-"-~--""---.' .1]'['---
(( .- t <;-~r' ..- :::<];1'/ , .: .>:::> ~ 11 '<::':"/f/,' .' U':/ \~
~ ~. ..--<;:>/ >::;> ~ // Jr'<" .;/ "\
.-;:::7 -"'-:'./, /( II ~'.' /,.
- ..,-' .... 'I f/, VI." --
~rl~~=r=lr=~!===-~I(~ ,/ }~-')/7/\nn-
~
~EPA
".1
~
I"
-------
TABLE 2
(VOC)
GROUND-WATER SAMPLES
ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH. FLORIDA
PHASE I - AUGUST 1992
HCL
PA-OI-GW
MW-i15
DRINKING
PA-03-GW PA-02-GW
PRIVATE ON-SITE
IRRIGAT'N EXT-WELL
PURGEABLE ORGANIC COMPOUNDS
119 II
11911
11911
ETHYL BENZENE
O-XYLENE
(M- AND/OR P-)XYLENE
TOLUENE
I19/L
700
10.000
10,000
100
4.4J
4.1J
8.8J
5.0J
TR ICHLOROETHENE
(TRICHLOROETHYLENE)
TRANS-l,2-DICHLOROETHENE
CIS-l,2-DICHLOROETHENE
VINYL CHLORID£
5.0
100
70
2.0
32
1. IJ
76
12
170
28
TEMPORARY MONITOR WELLS
PHASE II - SEPTEMBER 1992
MCL 001-TWA 001-TWB 002-TWA 002-TWB 003-TWA 003-TWB
40' BLS 80' BLS 40' BLS 80' BLS 40' BLS 80' BLS
PURGEABLE ORGANIC COMPOUNOS 11911 119/1 119 11 11-911 11-911 11-911 11911
TRICHLOEbETHENE
(TRICHLOROETHYLENE) 5.0
TRANS-i.2-DICHLOROETHENE 100
CIS-l,2-DICHLOROETHENE 70 1.2J
VINYL CHLORIDE 2.0
MUNICIPAL WELLS AND EXTRACTION WELL
PHASE II - SEPTEMBER 1992
015-PW 016rPW 019-PW 152-PW 153-PW 154 -MW EXT-MW 002-MW
MCL MW-U5 MW-U6 MW-U9 MW-U5.2 MW-U5.3 MW-#15.4 ON-SITE ON-SITE
DRINKING DRINKING DRINKING MONITOR MONITOR MONITOR EXT-WELL MONITOR
PURGEABLE ORGANIC COMPOUNDS 11-911 119 11 119 11 11-911 11911 11-9 11 119 11 119 11
ETHYL BENZENE 700 4.8J
O-XYLENE 10,000 2.2J
(M- AND/OR P-)XYLENE 10.000 8.6J
TOLUENE 1000 7. 2J
TRICHLOROETHENE
(TRICHLOROETHYLENE) 5.0 40
TRANS-l,2-DICHLOROETHENE 100 2.0J
CIS-l,2-DICHLOROETHENE 70 36 19 6.7 270
l,l-DICHLOROETHENE
(l,l-DICHLOROETHYLENE) 7.0 2.6J
VINYL CHLORIDE 2.0 5.9J 4.4J 30
FOOTNOTES:
I ~ ESt1MATm VALUE
- . MATUIAL WAS ANAL\'ZID FOR Bt1T" NOTDE'reCTED
119 II
300
15J
730
18J
.,..
12
-------
MCL
PURGEABLE ORGANIC COMPOUNDS
fl9/l
TRICHLOROETHENE ,
(TRICHLOROETHYLENE)
TRANS-l,2-DICHLOROETHENE
CIS-l,2-DICHLOROETHENE
l,l-DICHLOROETHANE
VINYL CHLORIDE
5.0
100
70
5.0
2.0
MCL
004-TWA
40' BLS
MONITOR
flg/l
J.7J
015-MW
MW-U5
DRINKING
004-TWB
80' BLS
MONITOR
fl9/l
016-MW
MW-"16
DRINKING
PURGEABLE ORGANIC COMPOUNDS fly/l fl9!l fl9!l
(M- AND/OR P-IXYLENE 10,000
ETHYL BENZENE 700
O-XYLENE 10,000
TOLUENE 1000
TRICHLOROETHENE
(TRICHLOROETHYLENE/ 5.0
CIS-l,2-DICHLOROETHENE 70 68A
VINYL CHLORIDE 2.0 20
FOOTNOTES:
A
J
- AVERAGE VALUE (SAMPLE
- ESTIMATED VALUE
- MATERIAL WAS ANALYZED
!I
TABLE 2
(Continued)
GROUND-WATER SAMPLES
ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION.
VERO BEACH, FLORIDA
PHASE III - JUNE 1993
005-TWA
40' BLS
MONITOR
fl9/l
019-MW
MW-U9
DRINKING
fl9/l
TEMPORARY WELLS
005-TWB
80' BLS
MONITOR
fl9/l
PERMANENT WELLS
152-MW
MW-U5.2
MONITOR
fl9/l
7.8
2.9J
006-TWA
40' BLS
~IONITOR
fl9/l
15l-MW
MW-U5.J
~IONITOR
fl9/l
006-TWB
80' BLS
MON ITOR
fl9/l
1.IJ
2.8J
154-MW
MW-U5.4
MONITOR
flg!l
5.7
ANALYZED TWICE AND AVERAGED)
FOR BUT NOT DETECTED
13
203-MW
MW-"20.3
MONITOR
fl91l
204 -MW
MW-"20.4
MONITOR
flg/1
205-MW
MW-"20.5
MONITOR
f1g/l
EXT-MW
ON-SITE
EXT-WELL
fl9!l
12.AJ
S.6J
5.8AJ
8.0AJ
17.AJ
160A
27
002-MW
ON-SITE
MONITOR
IIg/l
SO
120
-------
However, the concentrations detected, 1 ~g/l to 15 ~g/l, are much
less than the current MCL of 100 ~g/l.
East of the site 1,1-dichloroethane was detected in the
shallow temporary well PA-004-TWA less than the MCL of 5 ~g/l.
1,1-dichloroethene (l,l-dichloroethylene) was detected once
on-site in the extraction well during the Phase III sampling event
at a concentration less than Florida standard of 1 ~g/l.
Vinyl chloride is a chemical degradation product of TCE. The
Federal MCL for vinyl chloride is 2.0 ~g/l. Vinyl chloride was
detected in both on-site wells, EXT-WELL and MW-02, at 18 ~g/l and
30 ~g/l, respectively. Vinyl chloride has migrated off-site to the
municipal drinking water well, MW #15. The levels detected during
three sampling events range from 5 ~g/l to 20 ~g/l, which are
greater than the MCL. These levels indicate that the municipal
well has a potential overriding affect in ground-water movement at
the site. Vinyl chloride has migrated to the east to a deep
monitor well MW #15.2 and the concentrations demonstrate a marked
decre?se from Phase II and Phase III sampling events (Table 2 and
3) .
The Canal is acting as. a hydraulic barrier preventing the
contaminants from migrating to the south side of the Canal (e.g.,
no VOCs detected south of the canal) .
5.3.3 Surface Water and Sediment Investigations
Six sets of surface water and sediment samples were collected
from the Canal during Phase I. Two additional surface water and
sediment samples were collected during Phase II. These samples
were used to establish the extent of VOC migration in surface
water. The sample locations were selected based on accessibility,
depositional characteristics in the canal, location of the
pipelines, and confluence of the ditch and canal. A
background/control sample was collected west of the confluence of
the west ditch and main canal.
Trichloroethene (TeE), cis-1,2-dichloroethene, and vinyl
chloride were detected in the first sample located downstream of
the spray nozzle system, PA-06-SW. As a result of these findings,
two more surface water samples, PA-007-SW and PA-008-SW, were
collected farther downstream during Phase II (September, 1992).
Cis-1,2-dichloroethene was the only compound detected in these two
samples (Table 4a) .
No purgeable organic compounds were detected in any sediment
samples (Table 4b). No pesticides or PCBs were detected in the one
surface water/sediment sample collected. ..... iC.-
14
-------
TABLE 3
GROUND-WATER - VOC MIGRATION SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH. FLOR IDA
ON-SITE (VOC's)
Phase I Phase II Phase I I I
EXT-WELL EXT-WELL EXT-WELL
PURGEABLE ORGANIC COMPOUNDS /19 11 /1911 /19 11
ETHYL BENZENE 4.4J 4.8J 5.6J
O-XYLENE 4.IJ 2.2J 5.8AJ
(M- AND/OR P-) XYLENE 8.8J 8.6J 12.AJ
TOLUENE 5.0J 7.2J 8.0AJ
PURGEABLE ORGANIC COMPOUNDS
TR I CHLOROETHENE
(TRICHLOROETHYLENE)
TRANS-I.2-DICHLOROETHENE
CIS-l.2-DICHLOROETHENE
I.I-DICHLOROETHENE
(1.I-DICHLOROETHYLENE)
VINYL OiLORIDE
I I I
#15.2
PURGEABLE ORGANIC COMPOUNDS
TRANS-l.2-DICHLOROETHENE
CIS-l.2-DICHLOROETHENE
VINYL CHLORIDE
PURGEABLE ORGANIC COMPOUNDS
TRANS-l.2-DICHLOROETHENE
CIS-l.2-DICHLOROETHENE
I.I-DICHLOROETHANE
FOOTNOTES:
ON-SITE
(TCE AND DEGRADATION PRODUCTS OF TCE)
Phase I Phase I I Phase III Phase II Phase I! I
EXT-WELL EXT-WELL EXT-WELL MW-02 MW- 02
/19 11 /1911 /19 II /1911 /19/1
32 40 I7.AJ 300 50
15J 15
170 270 160A 730 120
2.6J
28 30 27 18J
~ SOUTHEAST
Phase I Phase I I Phase I I I PHASE I I PHASE I I I PHASE I I PHASE
MW #15 MW #15 MW #15 MW #15.4' MW #15.4 MW #15.2 MW
/19 II /19 11 /1911 /19 11 JL9 11 /19 11 JL9 11
1. IJ
76 36 68A 6.7 5.7 19 7.8A
12 5.9J 20 4.4J 2.9J
TEMPORARY MONITOR WELLS
WEST
~
Phase III
004-TWA 006-TWB
40' BLS 80' BLS
Phase II
002-TWB
80' BLS
11911
119/l
jL9/l
1.1J
2.8J
1.23
3.7J
A . AVERAGE VALUE (SAMPLE ANALVZED TWlCS AND AVEItAOED)
J - ES11MATfD vALUE
- . MA1ER1A1. W}S ANALVZED FOR BUT NOT DEm!CtI!b
...
15
-------
TABLE 4a
SURFACE WATER SAMPLES
ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH. FLORIDA
PHASE I - AUGUST 1992
MCL' PA-Ol-SW PA- 02 -sw PA-03-SW PA-04-SW PA-05-SW PA-06-SW
BCKGRND 27TH AVE 1st PIPE: 2nd PIPE UPS NZZL DNS NZZL
PURGEABLE ORGANIC COMPOUNDS JI.9/1 JI.9/1 JI.9/1 I1g /I I1g/l I'g/l 119/ I
(M- AND/OR P-)XYLENE 10.000
ETHYL BENZENE 700
O-XYLENE 10.000
TOLUENE 100
TRICHLOROETHENE
(TRICHLOROETHYLENE) 5.0 0.78AJ
TRANS-l.2-DICHLOROETHENE 100
CIS-l.2-DICHLOROETHENE 70 5.3AJ
VINYL CHLORIDE 2.0 0.53A.J
PHASE II - SEPTEMBER 1992
MCL 007 -sw 008-SW
DS NZZL US RXR
PURGEABLE ORGANIC COMPOUNOS JI.9/1 I1g/l 119 /I
CIS:l,2-DICHLOROETHENE 70 1. 4J 1. 2J
(Metals)
PHASE I - AUGUST 1992
MCL PA-Ol-SW PA-02-SW PA-03-SW PA-04-SW PA-05-SW PA-06-SW
BCKGRND 27TH AVE 1st PIPE 2nd PIPE UPS NZZL DNS NZZL
INORGANIC ELEMENTS m9/1 mg/l mg/I mg/l mg/l mg/l
CALCIUM 92 90 91 95 96 100
IRON 0.59 0.62 0.60 0.47 0.46 0.55
MAGNESIUM 22 22 23 24 24 24
POTASSIUM 4.6 4.9 5.0 4.6 4.4 4.4
SODIUM 110 100 110 120 120 120
I1g /I JI.9/1 I1g/1 JI.9/1 I1g/l JI.9/1 I1g /I
ALUMINUM 150 180 160 140 170 210
BARIUM 2000 36 36 37 36 36 36
MANGANESE 58 61 74 65 64 64
STRONTIUM 3100 3000 3400 3600 3600 3500
TITANIUM 11
ZINC 15 16 16 15 15 16
FOOTNOTES:
. . MCL . Muimam Cootaminam t.c..:1
A - AVERAGE VALUE
J . ESllMAn:D VALUE
- - MATERIAL WAS ANALYZED FOR BUT NOT DETECTED
16
..--
-------
TABLE 4b
SEDIMENT SAMPLE ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH. FLORIDA
PHASE I - AUGUST 1992
PA-01-SD PA-02-SD PA-03-SD PA-04-SD PA-05-SD PA-06-SD PA-07 -SIX:
BCKGRND 27th AVE 1st PIPE 2nd PIPE UPS NZZL DWS NZZL WEST DITCH
EXTRACTABLE ORGANIC COMPOUNDS jlg/kg I'g/kg I'g/kg I'g/kg I'g /kg I'9/kg I'g/kg
BENZO(AIANTHRACENE 180J
BENZO(B AND/OR K)FLUORANTHENE 240J
BENZOFLUORANTHENE (NOT B OR K) 200JN
CHRYSENE 230J
FLUORANTHENE 500J
PHENANTHRENE 250J
PYRENE 380J
BENZYL BUTYL PHTHALATE 1600
PESTICIDE/PCB COMPOUNDS jlg/kg jlgl kg jlg/kg I1g/kg 119/kg 119 1 kg fL9/kg
ALPHA-CHLORDANE 12 NA NA NA NA NA NA
CIS-NONACHLOR 12 NA NA NA NA NA NA
GAMMA-CHLORDk~E 12 NA NA NA NA NA NA
TRANS-NONACIiLOR 12 NA NA NA NA NA NA
HEPTACHLOR NA NA NA NA NA NA
HEPTACHLOR EPOXIDE NA NA NA NA NA NA
INORGANIC ELEMENTS mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg
ALUM INUM 290 200 900 9800 5400 2400 2400
ARSE;NIC 3.4 1.8 0.8 3.0
BAR IUM 1.7 1.9 4.5 46 13 22 7.0
CALCIUM 830 650 2600 1900D 1400 180000 2600
CH ROM IUM 2.0 17 6.0 78
COPPER 2.7 33 7.3 79 5.1 12
IRON 210 220 800 13000 2300 1900 930
LEAD 0.85 0.61 1.6 22 2.9 6.3 11
MAGNESIUM 27 29 110 1200 320 1800 200
MANGANESE 2.3 2.2 7.6 80 32 94 4.5
MERCURY 0.12 0.06 0.08
SODIUM 360
STRONTIUM 10 12 37 380 74 780 27
TITANIUM 40 17 74 36 65 79 34
VANADIUM 1.9 16 4.4 3.8
YTTRIUM 5.5 1.5
ZINC 4.8 4.2 10 110 8.0 20 58
FOOTNOTES:
NA - NOT ANALYZED. PA-OS-SD was..1ecocd aod submitted fo.- PcsIicOlolPCB analysis.
I . ESTIMATED VAllJE
N . PRESUMPTIVE EVIDENCE OF PRESENCE OF MATERIAL
- . MATERIAL WAS ANALY2ED FOR BUT NOT DETECTED
{2 . CONS11TIJENTS OR METABOUTES OF TECHNICAL OILORDANE
~.-
17
-------
Prior to the RI, EPA nor its contractors had collected samples at
the PAC site; and in order to satisfy the inorganic portion for the
site, samples were also collected and analyzed for inorganic
elements. The concentrations of metals detected in the surface
water and sediment samples, were not signifcantly above the
concentrations detected in the control samples.
5.3.4 Air Investigation
Four 24-hour air samples were collected over a two day period.
Sites.were chosen to evaluate the potential release of VOCs to the
air from the aeration of volatiles via the spray nozzles at the
canal. Wind direction was determined by calling the control tower
at the airport. A duplicate sample was collected at the downwind
station each day. A total of six canisters were set out.
Two compounds were detected in the downwind sample, PA-01-AIR
(Figure 4). 1,l-dichloroethene (1,l-dichloroethylene) was detected
at 16 ~g/m3 and l,l,1-trichloroethane was detected at an estimated
value of 4,100 ~g/m3. In addition to these compounds, toluene was
detected in the same sample at an estimated value of 12 ~g/m3
(Table 5). l,l,1-trichloroethane is used to clean the controller,
a diaphragm used to regulate flow into the canister. The source
for 1,1-dichloroethene is not known. On the other hand, toluene is
associated with fuels and could be found in the air near airports.
6.0 Summary of Site Risks
"Actual or threatened releases of hazardous substances from
this site, if not address by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment...
CERCLA directs EPA to conduct a baseline risk assessment to
determine whether a Superfund Site poses a current or potential
threat the human health and the environment in the absence of any
remedial action. The baseline risk assessment provides the basis
for taking action and indicates contaminants and the exposure
pathways that need to be addressed by the remedial action. This
section of the ROD contains a summary of the results of the
baseline risk assessment conducted for this site.
6.1 Contaminants of Concern
Chemicals which were evaluated in the risk assessment are
referred to as chemicals of potential concern (COPCs). The
selection of the COPCs is based on several factors including
chemical toxicity, prevalence and concentration.
Chemicals were included in the Summary of Site Risk Section if
the. results of the risk assessment indicate that a COPC migHt pose
a significant current or future risk. These chemicals are referred
18
-------
&EPA
~
I-'
I.C
... .
~I
.. LEGEND
- SAMPLE
XX - LOCA no LOCATION
APPROX N NUMBER
1200 IMATE SCALE
~ - ~ 6,00 1200
-~I
( IN rEET )
1 Inch = 1200 ft.
~ ~.
. .
-------
TABLE 5
AIR SAMPLES
ANALYTICAL DATA SUMMARY
PIPER AIRCRAFT CORPORATION
VERO BEACH, FLORIDA
PHASE I - AUGUST 1992
PA-OI-AIR PA-02-AIR PA-03-AIR PA-04-AIR
PURGEABLE ORGANIC COMPOUNDS J.lg/mJ J.lg/mJ J.lg/mJ J..lg/mJ
TOLUENE 12J NA NA
l,l-DICHLOROETHENE
(l,l-DICHLOROETHYLENE) 16 NA NA
1,1,~-TRICHLOROETHANE 4100 NA NA
FOOTNOTES:
NA . NOT ANAl.. \'ZEI)
- . MATI!lUAL WAS ANALYm:> FOR BLT NOT DEICCTI!I>
..... ~.-
:20
-------
TABLE 6
EXPOSURE POINT CONCENTRATIONS
Chemicals of Concern
Exposure Point Concentration
Groundwater Current Scenario (mq/l)
Vinyl Chloride
.009
Ground Water Future Scenario (mq/l)
l,l-Dichloroethene
cis-1,2-Dichloroethene
Strontium
Trichloroethene
Vinyl Chloride
Air (u.q 1m3)
l,l-Dichloroethene
1, 1, 1-Trichloroethane
Toluene
.003
0.22
0.99
0.30
0.03
16
4100
12
-'P ii-
. 21
-------
to as COCs. The criteria for determining the COCs are those
contaminant that contribute to a pathway that exceeds a 1E-4 risk
or a hazard index (HI) of 1; chemicals contributing risk to these
pathways are not included if their individual carcinogenic
riskcontribution is less than 1E-6 or their noncarcingenic hazard
quotient (HQ) is less than 0.1.
The COCs that meet the above criteria and the exposure
concertrations for these chemicals are contained in Table 6.Ground
water and air are the only media containing chemicals meeting the
cac criteria. The exposure concentrations represent the 95 percent
upper confidence limit (DCL) on the exceeds the maximum.
6.2 Exposure Assessment
Whether a chemical is actually a concern to human health and
the environment depends upon the likelihood of exposure, i. e.
whether the exposure pathway is currently complete or could be
complete in the future. A complete exposure pathway (a sequence of
events leading to contact wi th a chemical) is defined by the
following four elements:
A source and mechanism of chemical release,
.
A transport medium (e.g., surface water,
mechanisms of migration through the medium,
air)
and
.
The presence or potential presence of a receptor at the
exposure point, and
.
A route of
absorption) .
exposure
(ingestion,
inhalation,
dermal
If all four elements are present, the pathway is considered
complete.
An evaluation was undertaken of all potential exposure
pathways which could connect chemical sources at the site with
potential receptors. All possible pathways were first hypothesized
and evaluated for completeness using the above criteria. Eight
current exposure pathways and eight future exposure pathways
remained after screening. The current pathways represent exposure
pathways which could exist under current site conditions while the
future pathways represent exposure pathways which could exist, in
the future, if the current exposure conditions change.
Three age groups were evaluated for the residential scenarios i
child (1-6 years), child (7-12 years) and an adult. Body weights
of 15 kg and 27 kg were used for 1-6 years and 7-12 years
respectively. A 70 kg body weight was assumed for the adult. The
ingeStion rate was assumed to be 1 liter for the child and-~2 ~:iters
per day.
..
22
-------
The potential current and future exposure pathways are:
Ingestion of groundwater by a current or future resident;
Inhalation of VOCs while
future resident;
showering by or current
or
Incidental ingestion of surface water by children ages 7-
12;
Dermal contact with surface water by children ages 7-12;
Ingestion of fish by children ages 7-12 and residents
only;
Incidental ingestion of sediment by children ages 7-12;
Dermal contact with sediment by children ages 7-12;
Inhalation of ambient air by site worker or current or
future resident;
6.3
.
Toxicity Assessment
Toxicity values are used in conjunction with the results of
the exposure assessment to characterize site risk. EPA has
developed toxicity values for many carcinogens and noncarcinogens.
Cancer slope factor (CSF) have been developed for estimating
excess lifetime cancer risks associated with exposure to
potentially carcinogenic chemicals. CSFs, which are expressed in
units of (mg/kg/day)-l, are multiplied by the estimated intake of
a potential carcinogen, in mg/kg/day, to provide an upper-bound
estimate of the excess. lifetime cancer risk associate with exposure
at that intake level. The term "upper bound" reflects the
conservative estimate of the risks calculated from the CSF. Use of
this conservative approach makes underestimation of the actual
cancer risk highly unlikely. Cancer slope factors are derived frpm
the results of human epidemiological studies or chronic animal
bioassays to which mathematical extrapolation from high-to-low dose
and uncertainty factors have been applied.
Reference doses (RfDs) have been developed by EPA for
indicating the potential for adverse health effects from exposure
to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg/day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals that
are likely to be without risk of adverse effect. Estimated intakes
of chemicals from environmental media can be compared to the RfD.
RfDs are derived from human epidemiological studies or animal
. studies to which uncertainty factors have been applied (-oe .'9'., to
account for the use of animal data to predict effects on humans) .
23
-------
1- - ---
(See table 7). These uncertainty factors help ensure that the RfDs
will not underestimate the potential for adverse noncarcinogenic
effects to occur.
6.4
Risk Characterization
Human health risks are characterized for potential
carcinogenic and noncarcinogenic effects by combining exposure and
toxicity information. Excess lifetime cancer risks are determined
by multiplying the estimated daily intake level with cancer potency
factor. These risks are probabilities that are generally expressed
in scientific notation (e.g., lxlO-6). An excess lifetime cancer
risk of lxlO-6 indicates that, as a reasonable maximum estimate, an
individual has a one in one million additional (above their normal
risk) chance of developing cancer as a result of site-related
exposure to a carcinogen over a 70-year lifetime under the assumed
specific exposure conditions at a site.
EPA considers individual excess cancer risks in the range of
lxlO-4 to lxlO-6 as protective; however, the lxlO-6 risk level is
generally used as the point of departure for setting cleanup levels
at Superfund sites. The point of departure risk level lxlO-6
expresses EPA' s preference for remedial actions that result in
risks at the more protecti v~ .end of the risk range.
The potential for non-carcinogenic effects is evaluated by
comparing an exposure levelover a specified time period (e.g.,
life-time) with a reference dose derive for a similar exposure
period. The ratio of exposure to toxicity is called a hazard
quotient (HQ). An HQ
-------
TABLE 7
Toxicity Values
I CANCER SLOPE FACTORS (mg/kg-day) -~ I
I Chemical I Oral I Inhalator I
l,l-Dichloroethene 6.0E-l 1.75E-l
Trichloroethene 1.lE-2 6E-3
Viny.l Chloride 1.9E+O 3.0E-l
I REFERENCE DOSES (mg/kg-day) I
I CHEMICAL I ORAL I INHALATION I
l,l-Dichloroethene 9.0E-3 9.0E-3
cis-l,2-Dichloroethene 1.OE-2 1.OE-2
Strontium 6.0E-l -
Toluene 2.0E-l 1.14E-l
1, I,l-Trichloroethane 9.0E-2 2.86E-l
-? ~..
25
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The current scenario is based on a potential current scenario;
not on actual current exposures. The current potential scenrio
assumes that ground water from Vero Beach Water and Sewer
Production Well 15 is currently being used without treatment. This
does not represent actual exposures since the water is treated to
acceptable levels before being released into the distribution
system. In addition, this screnario assumes that a house is
located adjacent to the spray treatment nozzle on the main relief
canal and that residents daily breathe the air in the vicinity of
the nozzle over a 30 year expoxure period.
The cumulative potential current residential carcinogenic risk
level is 1.1E-3. The two media pathways responsible for this risk
level are ground water and air. The ground water risk of (3.9E-4)
can be wholly attributed to vinyl chloride. The air pathway risk
(6. 8E-4) is due to the presence of 1,1 -dichloroethene in the
vicinity of the spray treatment nozzle. The exposure to surface
water and sediments and the ingestion of fish did not produce
unacceptable risk levels.
1he cumulative cancer risk level for the future resident is
1.8E-3. The ground water risk of 1.lE-3 can be attributed to 1,1 -
dichloroethene, trichloroethene and vinyl chloride. The risk
associated with future inhalation of air near the spray treatment
nozzle is 6.8E-4. This is due to 1,1 -dichloroethene. The risks
associated with exposure to surface water and sediment and fish
ingestion did not produce unacceptable risk levels. The
contaminant-specific carcinogenic risk levels are contained in
Table 8.
The HIs for the potential current resident are 20, 10 and 5
for 1-6 years, 7-12 years and adult, respectively. Air was the
only exposure media contributing to a HI greater thanl.O. The air
chemicals with a HQ greater than 1.0 are 1,1-dichloroethene and
1, 1, I-trichloroethane.
The HIs for the future resident are 30, 20 and 8 for 1-6
years, 7-12 years and adult, respectively. Air and ground water
contributed to the risk levels greater than unity. The ground
water contaminants with HIs greater than 1.0 are cis-1,2-
dichloroethene and trichloroethene. The air contaminants with an
HI greater than 1.0 are 1,1-dichloroethene and 1,1,1-
trichloroethane. The noncarcinogenic risk levels are summarized in
Table 9.
In addition, maximum concentrations of cis-1, 2-dichloroethene,
trichlorothene and' vinyl chloride exceed federal ground water
standards (MCLs) and State of Florida standards. Violation of MCLs
or state standards generally warrant remedial action.
-y ~..
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I-
I
,
TABLE 8
Substances of Concern
That Pose a Carcinogenic Risk
Exceeding One in One Million (10.6)
Exposure Medium Current Resident Future Resident
Air Inhalation 1.1-Dichloroethene (6.8E-4) 1,1-Dichloroethene (6.8E-4)
Fish Ingestion NE NE
Ground Water Vinyl Chloride (3.9E-4) 1,1-Dichloroethene (3.6E-5)
Trichloroethene (7.9E-4)
Vinyl Chloride (9.9E-4)
Surface Water NE NE
Sediment NE NE
.? j;-
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Table 9
Substances of Concern (Reasonable Maximum Concentration)
Exceeding a Hazard Index of 0.1 when Hazard Index of Exposure scenario Exceeded 1.0
Exposure Current Resident Future Resident
Medium
1-6 year old 7-12 year old Adult 1-6 year old 7-12 year old Adult
Ground Non\) None None Strontium (1.lE-l) Ci8-1,2- C18-1,2-
Water C18-1,2- Dich10roethene Dichloroethene
Dichloroethene (1.6B+O) (1.2B+O)
(2.8E+O) Trichloroethane Trichloroethane
Trichloroethene (3.6E+O) (2.9E+O)
(6.4E+O)
Surface NB None NE NE None NE
Water
Sediment NE None NE NE None NE
Air Toluene (1.4B-1) 1,1- 1,1- 1,1-Dichloroethane 1,1- 1,1,1-
1,1- Dichloroethene Trichloroethane (2.3E+0) Dichloroethene Trichloroethane
D1chloroethene (1. 3E+O) (3.9E+0) 1,1,1- (1.3E+0) (3.9B+0)
(2.3E+0) 1,1,1- 1,1- Trichloroethane 1,1,1- 1,1-
1,1,1- Trichloroethane Dichloroethene (1.9R+1) Trichloroethane Dichloroethene
Trichloroethane (1.0E+1) (4.8B-1) Toluene (1.4B-1) (1.0E+l) (4.8E-l)
(1.9E+l)
Pish NB None None NR None None
NE - Not Evaluated
l'
28
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6.5
Environmental Risk
A qualitative risk assessment was conducted to determine if
contaminants present in site ground water and sediment have
impacted or can potentially impact flora and fauna in the area. As
a primarily industrial/commercial property with extensive areas of
asphalt, there is little suitable habitat for terrestrial flora and
fauna. Given the industrial nature of the site and the surrounding
area, impacts to local flora and fauna are not expected. No
endangered or threatened species have been identified in the
immediate vicinity of the site.
6.6
uncertainties
At all stages of the risk assessment, conservative estimates
and assumptions were made so as not to underestimate potential
risk. Nevertheless, uncertainties and limitations are inherent in
the risk assessment process.
Site specific uncertainties include the following:
The assumption that .air concentrations in the residential
areas are the same as monitored by the air canisters will
overestimate the risk.
The "worst case"
the canal will
inhalation.
assumption of people residing next to
overestimate risk associated with
The assumption that VOCs will not degrade over time will
overestimate the risk.
7.0 Description of Alternatives
The following site specific alternatives represent a range of
distinct actions addressing human health and environmental
concerns. The analysis presented below reflects the fundamental
components of the various alternatives considered feasible for this
site.
Four ground water (GW) alternatives have been identified for
evaluation and are listed below:
Alternative GWI
Alternative GW2
Alternative GW3
. ..Alternative GW4
No action
Ground Water Use Restrictions
Ex-Situ Treatment;Effluent Discharge
In-situ Treatment {bioremediatidh)i'..
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7.1
Alternative GW 1 - No Action
Under the no action alternative, the site is left "as is" and
no funds are expended for monitoring or to actively control or
cleanup the ground water. The NCP requires consideration of this
alternative.
7.2
Alternative GW 2 - Ground Water Use Restrictions
Under this alternative, institutional controls would be
implemented to restrict the use of ground water in the area.
Restrictions would include deed restrictions preventing current and
future use of the contaminated aquifer for such purposes as potable
and industrial water supplies, and irrigation. Permit restrictions
would require the State of Florida to restrict all well drilling
permits issued for new wells which are or may be impacted by the
contaminated ground water plume. These restrictions would be
written into the property deeds to inform future property owners.
Ground water monitoring would be conducted to track the movement
and change in contaminant concentrations.
7.3
Alternative GW 3 - Ex-Si"tu Treatment
As part of this alternative the existing extraction well would
be kept in service and additional well(s) would be installed. The
extracted ground water would be pumped to either on-site or off-
site treatment facility.
The primary treatment component for treating the ground water
is air stripping. If required, the ground water would be filtered
prior to treatment or additional processing may be needed to attain
discharge criteria.
The air stripping process option is a unit operation in which
a volatile component of a solution is transferred into a gaseous
phase. The efficiency of the air stripping process is mainly
dependent on the air-to-water ratio, the contact time, the
temperature and the physical and chemical properties of the
constituents of concern.
Bench and or pilot studies may have to be conducted to
determine if the liquid effluent would have to undergo further
treatment prior to discharge. The vapor effluent, off-gas, may
have to undergo additional treatment to destroy or remove the
contaminants stripped from the ground water prior to being
discharged to the atmosphere.
-7 ~.
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7.3.1
Alternative GW 3a - Ex-Situ Treatment; Surface
Discharge
Treated water from the air stripper will be discharged to
surface water, at a location either on-site or off-site. On-site
discharge include treated ground water being discharged to an on-
site drainage ditch. Off-site discharge would include treated
ground water being discharged to the main relief canal or potable
water system. All discharges will meet NPDES permit criteria,
where applicable, or requirements of the City of Vero Beach should
discharge be to the potable water system.
7.3.2 Alternative GW3b - Ex-Situ Treatment; Gradient Control;
Injection Well Disposal
Alternative GW3b is identical to alternative.GW3a, except that
the treated ground water would be reinjected back into the aquifer.
The injection wells used for disposal would be down gradient of the
extraction wells. Re-injecting the treated ground water back into
the aquifer would provide gradient control of the ground water
plume.
7.4
Alternative GW 4 - In-Situ Treatment (Bioremediation)
Bioremediation schemes attempt to either stimulate naturally
occurring aerobic microorganisms to degrade contaminants in-situ,
or introduce microorganisms capable of degrading the contaminants.
Typically, biodegradable contaminants can be degraded at rates
which are orders of magnitude greater than the leaching rate of the
contaminants in an aquifer system, provided growth limiting
nutrients and oxygen are added.
7.4.1
Alternative GW4a - In-Situ Treatment; Injection Well
Alternative GW4a involves the use of in-situ bioremediation to
degrade the contaminants of concern in the aquifer. The process
involves installing a(n) injection well(s) at an appropriate
location(s) which would be used to introduce microorganisms,
nutrients and an oxygen source. This system may require an
external source of water and a holding/mixing tank for combining
the water, nutrients and oxygen source prior to injection into the
aquifer.
7.4.2
Alternative GW4b - In-Situ Treatment;
Gradient Control; Ex-Situ Treatment;
Injection Well Disposal .
This alternative is similar to alternative GW4a in that the
majority of the degradation of the contaminants of concern is
accomplished through in-situ bioremediation. -? ~-
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This alternative also includes using injection well(s),
extraction well (s) and possibly, ex-situ treatment. The unit
processes involve installing an injection well(s) at an appropriate
location which would be used to introduce microorganisms, nutrients
and an oxygen source. An extraction well(s) would be installed
down gradient of the injection well (s) . An advantage of this
alternative is that the extraction well(s) would provide the source
of water needed to mix the microorganisms, nutrients and oxygen
source, and at the same time provide gradient control.. If the
extracted ground water needed additional treatment prior to
reinjection, an ex-situ treatment system could be added. This ex-
situ treatment system might include: media filtration, air
stripping, GAC adsorption or oxidation/UV photolysis.
8.0 Comparative Analysis of Alternatives
The alternatives are evaluated against one another by uS1ng
the following nine criteria:
.Overall protection of human health and the environment.
.Compliance with Applicable or Relevant and Appropriate
.Requirements (ARARs).
-Long term effectiveness and permanence.
-Reduction of toxicity ,mobility, or volume through treatment.
-Short term effectiveness.
-rrnplementability.
-Costs.
-State Acceptance.
.Community Acceptance
The NCP categorized the nine criteria into three groups:
(1 )
Threshold criteria: the first two criteria, overall
protection of human health and the environment and compliance
with ARARs (or invoking a waiver), are the minimum criteria
that must be met in order for an alternative to be eligible
for selection
(2 )
Primary balancing criteria: the next five criteria are
considered primary balancing criteria and are used to weigh
major trade-offs among alternative cleanup methods
(3 )
Modifying criteria: state and community acceptance are
modifying criteria that are formally taken into account after
public comment is received on the proposed plan. State and
community acceptance is addressed in the responsiveness
summary of the ROD.
8.1
Comparative Analysis of Human Health and the Environment
The- comparative analysis of the alternatives proposed-~ctr this
Site are presented in this section.
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1.Overall Protection of Human Health and the Environment
With the exception of the no action alternative, all of the
alternatives would provide protection for human health and the
environment, to some degree. Alternative GW2 would require
institutional controls for prevention of direct contact or use of
the contaminated ground water. The remaining alternatives all
provide treatment of the contaminated ground water.
2.Compliance with ARARs
The no action alternative would not comply with ARARs because
contaminants would remain in excess of ground water action level
and contaminants would continue to migrate. A decrease in
contaminant concentration is anticipated with alternative GW2,
however, the decrease may not be sufficient to attain ARARs.
Alternatives GW3 both a&b, and GW4 both a&b, include ground water
treatment, and would comply with ARARs. Alternative GW3a would
meet the ground water remedial goals established for the site and
surfa€e water discharge requirements prior to discharge to the
canal or other discharge criteria established for discharges to the
potable water system. GW3b i~ expected to comply with ARARs, as a
result of ground water having to be treated to MCL's and/or other
limitations established by the Underground Injection Control
Regulations of FDEP. Both GW4a and GW4b use an in-situ
bioremediation process that would continue until the goals were
attained; however, alternative GW4's compliance is largely
dependent on the degradative abilities of the microorganisms.
Alternative GW4b may also include additional measures such as air
stripping, GAC adsorption, etc. to ensure compliance with ARARs.
3.Lonq-Terrn Effectiveness and Permanence
All of the alternatives, with the exception of the "no
action", would reduce potential risks and/or environmental impacts.
Alternative GW2 would not provide for active remediation and,
therefore, contamination would remain for an extended period of
time. Long term monitoring results and actual effectiveness of the
institutional controls would require periodic reassessment for
alternative GW2. Th~ treatment process in alternatives -GW3 a&b
would be monitored and modified as necessary to insure the
effectiveness of the treatment system in attaining cleanup goals.
The effectiveness of alternatives GW4 a&b is dependent on the
ability of the microorganisms to feed on the contamination.
4.Reduction of Toxicity, Mobility, and Volume
--- _~ll of the alternatives will aid in the reduction of toxicity,
mobility and volume with the exception of GWl & GW2. -"r ~iether
alternat~ve would provide for reduction in toxicity, mobility, or
33
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volume of contaminated ground water. Alternative GW 3 & 4 both
provide for a reduction of contaminant levels to attain MCL. By
reducing the concentration, the mobility, toxicity and volume of
the contaminated ground water is reduced.
5.Short-Term Effectiveness
with the exception of alternatives GWI and GW2 (which provide
no treatment of the contaminated ground water), all the
alternatives present some potential risks to remediation workers
and the environment during implementation. These risks would be
controlled during construction by restricting access in the
.construction area and implementing a Health and Safety Plan. In
alternative GW3a&b the treatment facilities would be located within
the fenced area, to insure the integrity of the treatment unit and
further restrict public access the treatment unit.
6. Implementabilitv
The no action alternative (alternative GWl) is the easiest to
implement yet it provides no protection of human health and
environment. The second alternative would require the negotiation
of institutional controls to provide any degree of protectiveness.
Treatment alternatives GW3 and GW4 may require that a treatability
study or pilot test be performed to design the treatment process.
Alternative GW3 a&b have both been demonstrated to be effective on
the contaminants of ,concern. It is anticipated that portions of
the existing system could be incorporated into the design of this
system Alternative 3b would be more difficult to implement than 3a,
due to the greater potential for additional treatment necessary for
re-injection of treated ground water. Alternative 4 a&b rely on
enhancement of the natural degradation of contamination, and the
effectiveness of the overall treatment process may be questionable.
The insitu process could be difficult to control. Since TCE
degrades to vinyl chloride, alternative 4 may cause an increase in
vinyl chloride concentration in the ground water.
7.Cost
A summary of the present worth costs (Capital and O&M)
each of the alternatives is presented below:
for
... j;..
34
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Alternative Description Capital O&M Cost Total - Construction
Cost/ Annual Capital & Period
Range Cost/ 10 Yr O&M
Range Range
Alt. No. 1 No Action $0 $0 $0 Not
Applicable
Alt. No. Groundwater $29,500 $79,400 $605,380 Not
GW2 Monitoring Applicable
Restrictions
Alt. No. Ex-Situ/Surf $857,3755 $155,125 $1,955,878 Four Months
GW3a Discharge
Alt. No. Ex-Situ/Well $888,250 $155,125 $1, 985,727 Four Months
GW3b Discharge
Alt. No. In-Situ/Ext. $1,003,125 $147,825 $2,043,744 Four Months
GW4a Water
.
Alt. No. In-Situ/Site $1,105,625 $146,000 $2,129,575 Four Months
GW4b Water
Note:
Cost listed in above cost table for Alternative GW 3a&b
reflect purchase of only one additional well, more wells may
be needed. Also, if an alternative requires a Reverse Osmosis
for treatment of inorganic, EPA estimates that the cost will
be an additional $980,000 in capital cost and $195,000 in O&M
making the total - capital and 10 year O&M cost $2,364,127.
8.State Acceptance
The State of Florida, as represented by the Florida Department
of Environmental Protection (FDEP), has been the support agency
during the Remedial Investigation and Feasibility Study process for
the Piper Aircraft Corporation site. In accordance with 40 CFR
300.430, as the support agency, FDEP has provided EPA with input
during the process. Based upon .comments received from FDEP, it is
expected that written concurrence will be forthcoming; however, a
letter formally recommending concurrence of the remedy has not yet
been received.
.'r ii-~
35
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,--.-
9.Communitv Acceptance
The majority of comments. received during comment period
indicated the local community believes that Piper Aircraft has
acted responsibly and should be allowed to continue the remediation
process using the existing system. The community is concerned that
EPAwill cause Piper to go back into bankruptcy, due to the cost of
the remedy. If a remedy must implemented then the citizens would
prefer that Piper Aircraft perform the remedial design and remedial
action. EPA acknowledges the communities concerns and plans to
negotiate the implementation of the Remedial Design/Remedial Action
with Piper Aircraft Corporation.
8.2
Synopsis of Comparative Analysis of Alternatives
All the alternatives, except for No-Action, would provide some
degree of overall protection of human health and the environment
and would comply with ARARs. Alternative GW 3a represents the best
balance among the criteria used to evaluate remedies. GW3a is
believed to be protective of human health and the environment,
would attain ARARs, would be cost effective, and utilize
alter~ative treatment technologies or resource recovery
technologies to the maximum extent practicable.
9.0
SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the
NCP, the detailed analysis of alternatives and public and state
comments, EPA has selected GW 3a recover treatment of disposal as
the remedy for this site. At the completion of this remedy, the
risk associated with this Site has been determined to be in the
range from 1x10-4 to 1x10-6 which is considered to be protective of
human health and the environment.
The total present worth cost of the selected remedy,
Alternative GW 3a, is estimated at $1,955,878. This includes
capital costs $857,375 and annual O&M costs of $155,125.
A.
Ground Water Remediation
Contaminated ground water will be removed by pumping from
extraction welles) designed to provide effective capture of all
site related contaminants exceeding ground water clean-up goals.
The extracted ground water will then be treated by air stripping
and carbon polishing, as necessary, to meet surface water discharge
criteria. The treated ground water will be surfaced discharged via
drainage ditch or directly to the main relief canal. Discharges
from the treatment ~ystem to surface waters will be monitored and
controlled so as to avoid any adverse impact to aquatic habitats
supported by the receiving water body.
..... j;.-
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A.l
Components of Ground Water Remediation for
Implementation
Extraction of contaminated ground water and treatment by air
stripping at the Site; and
a. Treated ground water will be surface discharged via on-
site drainage ditch or main relief canal in accordance with
all applicable regulations, including 17-302 F.A.C. (General
and Class III surface water standards) and other Performance
Standards.
b. Air emissions will be modelled during RD and sampled
during the initial operation of the water treatment system.
Air emission control equipment will be added if EPA determines
such equipment is necessary to meet state and federal air
quality standards including 17-2, F.A.C.
A.2
Extraction, Treatment, and Discharqe of Contaminated
Ground Water
The VOC contaminated ground water will be treated by using the
air stripping technology to remove the VOCS. The specific type of
air stripping system will be determined during the RD and will
depend upon flow rates, influent concentrations, efficiency rates,
etc.
, ,
The need for treatment of inorganics will be determined during
the RD/RA. This may be accomplished during a pilot scale operation
of the air stripping tower. If contaminants are detected above
discharge standards, then appropriate treatment methods shall be
designed. If inorganic contaminants are detected consistently
during periodic effluent sampling from the full scale operation of
the ground water treatment system, then an EPA approved design for
inorganics treatment shall be implemented.
Treated ground water will be surface discharged to an on-site
drainage ditch or directly to the main relief canal. The treatment
system will include components to insure the effluent attains
discharge criteria at the exit point of effluent from the treatment
system. Discharge criteria include NPDES requirement and general
and Class III surface water standards as defined in 17-302, F.A.C.
A.3.
Performance Standards
a.
Extraction Standards
Site related ground water contamination which exceeds
federal and/or state ground water standards, particularly
those listed in the following table, will be extracted.
Current pumping rates of the existing treatment.. unit is
225 gpm. EPA estimated the pumping rate to range between
37
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700 gpm to 1000 gpm was be necessary to capture the
entire plume. The actual extraction rate and nUmber of
extraction well(s) will be established during the
remedial design. The goal of this remedial action is to
restore ground water to its beneficial use as a potential'
drinking water source. Ground water shall be treated
until federal and/or state ground water standards are
met. These standards include the levels listed in the
following table "Ground Water Cleanup Standards".
Some of the ground water treatment standards include
promulgated State ground water standards that are more
stringent than Federal standards. These State standards
are ARARs that shall also be complied with and include,
Chapters 17-550, F.A.C, 17-3, F.A.C., and 17-520 F.A.C.
and:
GROUND WATER CLEANUP STANDARDS
Federal/State
Chemicals MCL (pg/L)
in Ground Water
.
Trichloroethene 5.0/3.0
cis-l.2-Dichloroethene 70.0 / 70.0
Vinyl Chloride 2.0 /1.0
l,l-Dichloroethene 7.017.0
Federal and State MCLs are listed respectively
It may become apparent during the implementation or
operation of the treatment unit that contaminant levels
have ceased to decline and are remaining constant at
levels higher than the above treatment standards. In
such a case, the system's performance may be re-evaluated
by EPA, in consultation with FDEP.
b.
Treatment/Discharge Standards
Discharges from the ground water treatment system shall
comply with all ARARs prior to discharge to surface
water, including but not limited to, federal and state
surface water standards, substantive requirements of the
NPDES permitting program under the Clean Water Act, and
all effluent limits established by EPA as well as Florida
Regulations in Florida Administrative Code, Chapter 17-
302, general criteria and class III surface water
criteria.
.? ~-
38
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Air emissions from the ground water treatment system
shall comply with EPA Office of Solid Waste and Emergency
Response Directive 9355.0-28 titled Control of Air
Emissions from Superfund Air Strippers from Superfund
Ground Water Sites. This guidance indicates that air
emission sources need controls if their actual emission
rates for total VOCs exceed:
3 pounds/hour or
15 pounds/day or
10 pounds/day
Air emissions shall also comply with levels included and/or
referred to in the guidance document entitled "Estimation of
Air Impacts for Air Stripping of Contaminated Water"
(EPA-450/1-91-002, dated 5/91) .
Air emissions must also comply with State regulations
identified for this Site. Florida regulations in Florida
Admistrative Code, Chapter 17-2, provides requirements
for sources which emit pollutants. If any contaminant
regulated by these standards are released by the planned
remedial action, the regulations shall be followed.
. t,.
c.
Design Standards
The design, construction and operation of the ground
water treatment system shall be conducted in accordance
with all ARARS, including the pertinent requirements set
forth in 40 C.F.R. Part 264 (Subpart F).
.-,
B.
Compliance Testinq
A long-term monitoring system shall be implemented to monitor
the progress of ground water remediation and the effectiveness of
continued operation of the ground water treatment system. After
demonstration of compliance with ground water clean-up standards,
the ground water shall be monitored for at least five years. If
monitoring indicates that the ground water standards set forth in
Paragraph A.3 are being exceeded at any time after pumping has been
discontinued, extraction and treatment of the ground water will
recommence until the ground water standards are once again
achieved.
Treated ground water will also be monitored on a regular basis to
ensure that the treated water meets the necessary discharge
standards. Discharge standards include federal and state standards
for discharges to the surface water. An appropriate sampling and
analysis plan for the remedial action will be prepared during the
RD :-. . -In addition to analyses of organic contaminants, -:kn~rganic
contaminants will be analyzed. If, at any time, metals are present
39
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above federal or state standards, then treatment for metals may be
deemed to be necessary by EPA.
Air emissions monitoring will be performed periodically during the
remedial action to evaluate the air emissions from the treatment
system to determine if air emission controls are necessary. If
violations of state or federal standards are observed, the
treatment system will be modified as necessary to bring it into
compliance.
10.0 STATUTORY DETERMINATIONS
EPA has determined that the selected remedy will satisfy the
statutory determinations of Section 121 of CERCLA. The remedy will
be protective of human health and the environment, will comply with
ARARs, will be cost effective, and will use permanent solutions and
alternative treatment technologies to the maximum extent
practicable.
Furthermore, the regulatory preference for treatment as a
principal element and the bias against off-site land disposal of
untre?ted wastes are satisfied to the extent practicable.
10.1 Protection of Human Health and The Environment
The ground water treatment component of the selected remedy
will protect human health and the environment by reducing or
preventing further migration of the contaminated ground water and
by reducing the contaminant concentrations in ground water until
the concentrations are less than or equal to the performance
Standards. Compliance with MCLs will be protective at this site.
The long-term cancer risk associated with possible ingestion of the
ground water will be reduced to within EPA's acceptable risk range
of 1x10-4 and 1xlO-6 and the non carcinogenic risk would be reduced
to the EPA goal of 1. Periodic groundwater monitoring will be
conducted to evaluate the performance of the groundwater treatment
system.
10.2 Compliance with ARARs
Implementation of this remedy will comply with all Federal and
State ARARs and will not require a waiver. The groundwater
extraction and treatment system will meet the groundwater
performance standards noted in Section 9.A.3, which are based on
Federal and State MCLs. Federal and State MCLs are considered
relevant and appropriate in the cleanup of contaminated
groundwater. Performance standards will be met with respect to the
discharge of treated groundwater and long-term groundwater
monitoring to assess progress and effectiveness of cleanup.
.. . Air emissions from the groundwater treatment systemg;;..shall
comply with EPA Directive 9355.0-28 which provides guidelines for
40
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the control of air emissions from air stripping towers at Superfund
groundwater sites. In addition, State standards for air emissions
are found in FAC Chapter 17-2.300. These standards would apply if
regulated pollutants are emitted to the atmosphere during the
remedial action.
Treated water discharged to the surface shall meet the
standards required for surface water discharge includin~, but not
limited to, NPDES requirements.
10.3 Cost-Effectiveness
The selected remedy, Alternative GW 3a, is a cost effective
remedy. The total estimated present worth cost of this alternative
is $1,955,878 which includes capital costs and annual operation and
maintenance costs. EPA has determined that the cost of
implementing the remedy is appropriate given the threat dosed by
the contaminated ground water.
10.4 Use of Permanent Solutions and Treatment Technologies
The selected remedy uses permanent solutions and treatment
technologies to the maximum extent practicable. Ground water
extraction and treatment will involve active measures to reduce the
toxicity, mobility, and volume of contaminants in ground water.
10.5 Preference for Treatment as a Principal Element
The statutory preference for treatment will be met because the
selected remedy includes active treatment for ground water. Ground
water remediation will be accomplished through extraction and air
stripping of the contaminated groundwater. Air stripping will
remove the VOCs from groundwater and discharge them to the air at
levels that will not .pose an unacceptable level of risk to human
health or the environment.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The remedy described in this Record of Decision is the
preferred alternative described in the Proposed Plan for this Site.
There have been no significant changes in the selected remedy.
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APPENDIX
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RESPONSIVENESS SUMMARY
The u. S. Environmental Protection Agency (EPA) held a public
comment period from September 30 to October 29 for interested
parties to comment on EPA's Proposed plan for the Piper Aircraft
site, which addressed contaminated ground water. During the comment
period, EPA conducted a public meeting at the Vero Beach City Hall
in Vero Beach, Florida on October 20, 1993. During this meeting,
representatives of EPA presented the results of the studies
undertaken at the site and EPA's preferred alternative for
addressing ground water contamination.
A summary of EPA's response to comments received during the public
comment period, known as the responsiveness summary, is required
under Section 117 of CERCLA. EPA has considered all of the
comments summarized in this responsiveness summary in determining
the final selected remedy presented in the Record of Decision.
This responsiveness summary consists of the following sections:
A.
Backqround of Community Involvement and Concerns: This
section provides a brief history of community interest
and concerns regarding the Piper Aircraft site.
B.
Summary of Maior Ouestions and Comments Received During
the Public Comment Period and EPA' s Responses: This
section presents both oral and written comments submitted
during the public meeting and public comment period, and
provides the responses to these comments.
A.
Background of Community Involvement and Concerns
In accordance with Sections 113 and 117 of CERCLA, EPA has
conducted community relation activities at the Piper Aircraft site
to ensure that the public remains informed of the concerning
progress. During the numerous investigative activities, EPA held
meetings with the city and state officials to advise them of the
progress of activities at the site.
A community relations plan (CRP) was developed in 1992 to establish
EPA's plan for community participation during remedial activities.
Prior to the initiation of the RIfFS, EPA held an Availability
Session in Vero Beach, Florida to present to the public the
activities sched~led for the RIo Following completion of the
Remedial Investigation and Feasibility Study (RIfFS), a Proposed
Plan fact sheet was mailed to local residents and public officials
in September 1993. The fact sheet detailed EPA' s preferred
alternative for addressing the source of contamination at the Piper
Aircr"aft site. Additionally, the Administrative Record-?fc!r the
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site, which contains site related documents including the RI and FS
reports and the Proposed Plan, was made available for public review
at the information repository in the Indian River County Main
Library. A notice of the availability of the Administrative Record
for the Piper Aircraft site was published in the Press Journal,
which serves Vero Beach and the surrounding areas, on September 29,
1993, and again on October 17, 1993.
A 30-day public comment period was held from September 30, 1993, to
October 29, 1993, to solicit public input on EPA's preferred ground
water remediation alternative. Comments were received from
citizens of Vero Beach, and representatives for Piper Aircraft
Corporation and Piper Aircraft employees, City of Vero Beach Water
and Sewer Department, and Florida Department of Environmental
Protection (FDEP). The Piper Aircraft Corporation and it's
employees have expressed concerns about the selected remedy. Based
on comments received Piper feels they have acted responsibly and
should be allowed to continue their existing remediation process.
If a remedy must be done, then Piper has expressed interest in
designing and performing the selected remedy. FDEP has verbally
expressed agreement with the selected remedy.
In addition to the comment period, EPA held a public meeting in
Vero Beach, Florida on October 20, 1993, at the Vero Beach City
Hall to discuss the remedial alternatives under consideration and
to answer any questions concerning the Proposed Plan for the Piper
Aircraft Superfund site. The meeting was attended by approximately
60 area residents and public officials. EPA' s response to the
comments recei~ed at the meeting or during the comment period are
summarized in Section II below. Additionally, a transcript of this
public meeting was prepared by a certified court reporter, and this
document is a part of the Administrative Record upon which the
remedy selected in the Record of Decision is based.
Following the issuance of the final Record of Decision, EPA will
continue to keep the community informed about progress at the site
through fact sheets and informational meetings as needed.
Additionally, design and construction documents pertaining to the
implementation of the ground water remedy will be placed in the
information repository at the Indian River County Main Library.
II.
Summary of Maior Ouestions and Comments Received Durinq the
Public Comment Period a~d EPA's Responses
Comment:
1.
How current was the data that EPA used to write the Proposed Plan?
Response:
EPA relied on data from samples collected as part of the Remedial
Investigation (RI) to prepare the Proposed Plan. EPA's RI -sampling
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event was conducted in three phases; Phase I conducted in August
1992, Phase II conducted in September 1992; and Phase III conducted
in June 1993. EPA collected three ground water samples during
Phase I, fourteen samples during Phase II, and 7 samples during
Phase III. Six sets of surface water and sediment samples, were
collected from the Canal during Phase I, and two additional samples
were collected during Phase II. Two twenty-four hour composite air
samples along with one grab and one composite soil sample were
collected during Phase I sampling only. Sampling results are
available in the RI and are summarized in this ROD.
2.
Comment:
If the site was evaluated for the National Priorities List (NPL)
today, what would be the score?
Response:
EPA has revised the scoring system (i.e. Hazard Ranking System)
since Piper Aircraft was evaluated for placement on the NFL in
1985. However, under today's system Piper would probably receive
a score higher than the previous 31.13, due to the contamination of
the municipal well and the number of people affected by the
municipal well.
3.
Comment:
Why is EPA continuing to investigate the contamination at this site
when all the remedial action that needs to be taken to treat the,
ground water has been taken by Piper Aircraft?
Response:
As a Superfund site, EPA must ensure that the clean-up is conducted
in a manner such that ~ontaminants are reduced to levels that are
protective of human health and the environment. However, the
resul ts of EPA' s investigation indicate that the existing treatment
unit is not sufficient to treat the ground water to levels
protective of human health. Hence, modifications to the system are
necessary to achieve the proper degree of protection as required by
Federal and State Law.
4.
Comment:
What is the problem with the contaminant levels remaining at the
current concentration?
Response:
Contaminant concentrations are still well above the Federal and
State MCL. The maximum concentration of TCE detected was 100 times
greater than the MCL. The carcinogenic risk posed by us.in~u this
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contaminated ground water is 10-3, which is above EPA acceptable
risk range of 10-4 to 10-6. The non-carcinogenic risk posed by the
contamination is 30, which is 30 times greater than EPA's goal of
1.
5.
Comment:
Since one of the City's wells is located within the boundary of
contamination, are the citizens of Vero Beach drinking water with
elevated levels of contaminants?
Response:
No, the surrounding area is on municipal water which is treated by
the City of Vero Beach Water and Sewer Department. Based on
discussions with the City, city water is treated to levels below
the MCL.
6.
Comment:
If the drinking water was treated by the City why is it necessary
for EPA to propose additional treatment of ground water?
Response:
Presently, the City of Vero Beach is working with Piper Aircraft to
treat only that portion of the ground water necessary to provide a
safe source of drinking water to the public. However, under CERCLA
and the NCP EPA has a broader responsibility, to return
contaminated aquifers to the beneficial use. Moreover, EPA does
not feel it's appropriate to rely on the City to restore the
aquifer to it's beneficial use given that the City is not
responsible for the contamination. The selected alternative not
only ensures a safe drinking water source, but also restores the
aquifer. -
7.
Comment:
What was the maximum level of TCE that EPA detected when the site
was placed on the NPL?
Response:
The Preliminary Assessment conducted in December 1988 indicated a
maximum concentration of 301 ~/l. The maximum level of TCE
detected during the RI was 300 ~/l. Both these levels exceed the
State MCL of 3.0 ~/l.
8.
Comment:
How did EPA evaluate the inhalation risk posed by the open aeration
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system, and what was the assumed density of the population at the
spray head across the main canal?
Response:
The inhalation risk was calculated at 6.8 x 10-4 (EPA's acceptable
range is 10-4 to 10-6) should people reside in the vicinity of the.
spray heads. The actual number of residents in this area is zero.
Nonetheless, EPA must theorize the most conservative
scenario, thereby ensuring protectiveness. EPA must assume that it
is possible for people to come into contact with this
contamination. During several visits to the site we observed beer
cans and other signs of this area being used as a place of
congregation were observed.
Although the Risk Assessment indicates a risk in excess of EPA's
established risk range, it should be noted that this risk is based
on data collected from a monitoring station located close to the
spray heads. The contaminant levels significantly decreases as the
distance from the unit increases.
9.
Comment:
What is the extent of the plume and how far out should someone be
concerned if they wanted to drill a well?
Response:
Based on information collected during the EPA's RI, the migration
of the plume is limited to the south and southeast of the Piper
facility. No contamination was detected south of the main relief
canal. Monitoring well #15.2 (located approximately 1,000 feet due
east of the water tank) appears to be at or near the eastern edge
of the plume. Consequently, the aerial extent of the contaminant
plume is estimated from the drainage ditch to the west, the main
relief canal to the south, and a line 50 feet north of the
extraction well which runs east from the drainage ditch until it
intersects the main relief canal (Figure 1.2 of Feasibility Study) .
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10.
Comment:
Is there soil contamination present at the site?
Response:
In 1989, Piper removed contaminated soil surrounding an underground
storage tank. The dimensions of the excavation were 14 feet deep
by 40 feet wide by 100 feet long. The soil was aerated to remove
the TCE, tested, and used to backfill the excavation. This action
was conducted wi th oversight by FDER. According to EPA' s
confirmatory soil sampling conducted in June 1992, there is no
indic.ation of any remaining soil contamination. .7 jO..
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11.
Comment:
The citizens of Vero Beach and the management of Piper Aircraft are
interested to know if EPA will allow Piper an opportunity to
perform the remedial design and remedial action.
Response:
Pursuant to CERCLA Section 122 and 104, EPA will special notice
Piper Aircraft, following the selection of a remedial alternative.
The special notice will serve' to provide Piper Aircraft the
opportunity to negotiate a Consent Decree with EPA for the design
and implementation of the cleanup under EPA' s oversight. Following
the negotiation of a Consent Decree, Piper Aircraft will implement
the remedial design and remedial action. However, should
negotiation with Piper be unsuccessful, EPA will conduct the design
and construction using funds from the Superfund.
12.
Comments:
Why did EPA proceed with inclusion of this site on the NPL when
FDER was already taking action at the site to clean it up?
.
Response:
EPA has been aware of FDER's involvement with the Piper Aircraft
Site as early as September 1984, as stated in an EPA response to a .
letter opposing the EPA's policy for listing of the site from
Victoria J. Tschinkel, 1984 FDER Secretary. EPA stated then, as
well as now that the factors the Agency considered in developing
this HRS policy include the purpose of the NPL as stated in the
CERCLA legislative history, the objectives of protecting public
health and the environment, and the need to administer the program
consistently.
Once a site is placed on the NPL, EPA must adhere to the
requirements of 40 CFR 300.430 to remove the site from the NPL. An
RI and risk assessment must be performed in order to determine the
nature and extent of contamination, and to evaluate relative risks.
to human health and the environment. This information is used to
evaluate if remediation is warranted. The potentially responsible
parties are offered an opportunity to conduct this investigation
and every effort is taken to prevent duplication of any other
agency's efforts. If the RI reveals that the site is not a risk to
human health or the environment, the site may be removed from the
NPL. On the other hand, if the site is a risk to human health
and/or the environment, then a Feasibility Study is done followed
by a Remedial Design/Remedial Action (RD/RA). When the RA is
completed and cleanup goals attained, a site may be removed from
the NPL.
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13.
Comment:
Why did EPA not consider mixing the contaminated water with the
Vero Beach Water Supply, thus allowing the dilution of
contaminants?
Response:
EPA has evaluted this alternative, however, the City would require
treatment of ground water before discharging to the City water
supply. Thus, EPA would still have to treat the ground water.
14.
CODDD.ent:
Can the existing remediation unit (i.e. spray header and associated
water line and extraction well) which Piper installed be used as
part of the remedial action?
Response:
Yes, al ternati ve GW3a, the preferred remedy, incorporates the
existing system, to the extent practicable. In fact, the Piper
extraction well and the water lines associated with the well, if
practicable, will be included in the remedy design. Use of other
components of the existing system was not considered during the
est~ation of cost; however, the cost effectiveness of upgrading
these other components will be decided upon during the remedial
design.
15.
CODDD.ent:
Alternative GW3b, Ex-Situ Treatment; Gradient Control; Injection
Well Disposal is an option which may warrant more consideration.
This may be the lowest cost and most effective option.
Response:
Alternative GW3b would
thus, the remedy would
difficult to ~plement.
a premitting problem.
require re-injection of the ground water
not be the lowest cost and would be more
Iron exceeds secondary MCL and may present
16.
Comment:
Will EPA allow the reuse of the treated ground water?
Response:
If ground water meets EPA's clean-up levels, then ground water may
be reused if approved by EPA.
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