United States
Environmental Protection
Agency
Explanation of Significant Differences
Piper Aircraft/Vero Beach Water and Sewer
Superfund Site
Site Name:
CERCLA ID #:
Site Location:
Lead Agency:
Support Agency:
Piper Aircraft/Vero Beach Water and Sewer
Superfund Site
FLD004054284
2926 Piper Drive, Vero Beach, Florida
EPA, Region 4
Florida Department of Environmental
Protection
Vero Beach, FL
I. Introduction
This decision document presents an Explanation of
Significant Differences (BSD) for the Piper
Aircraft/Vero Beach Water and Sewer Superfund
Site (Site), located in Vero Beach, Florida. The
Record of Decision (ROD) dated December 23,
1993 is addressed by this ESD.
This ESD is issued in accordance with § 117(c) of
the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980
(CERCLA), 42 U.S.C. §9601 et seq., as amended
by the Superfund Amendments and Reauthorization
Act of 1986 (SARA), and the National Oil and
Hazardous Substances Pollution Contingency Plan
(NCP), §300.435(c)(2)(i). The Director of the
Superfund Division has been delegated the authority
to sign this ESD.
This ESD will become part of the Administrative
Record for the Piper Aircraft/Vero Beach Water and
Sewer Superfund Site (NCP §300.825(a)(2)), which
has been developed in accordance with §113(k) of
CERCLA, 42 U.S.C. §9613(k).
The Administrative Record is available for review
at the Indian River County Main Library, located at
1600 21st Street in Vero Beach, Florida and at the
United States Environmental Protection Agency
(EPA) Region 4, llth Floor Library, 61 Forsyth
Street SW, Atlanta, Georgia 30303.
II. Statement of Purpose
Since the ROD finalization date, issues concerning
institutional controls have been identified at the
Site. Institutional controls have been implemented
at the Site, but were not part of the selected remedy
in the 1993 ROD. In addition, the designed and
implemented remedy is not to the exact
specification as prescribed by the selected remedy.
However, similar alternatives were evaluated in the
ROD. The purpose of this ESD is to document a
final decision to include institutional controls in the
form of a groundwater delineated area as part of the
groundwater remedy for the Site, as well as
incorporate the modifications of the groundwater
treatment system into the groundwater remedy.
EPA prepares an ESD when it is determined by the
Agency that changes to the original selected remedy
are significant, but do not fundamentally alter the
remedy selected in the ROD with respect to scope,
performance, or cost.
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III. Site History and Contamination
Site History
Piper Aircraft, Inc. (Piper) operates an airplane
manufacturing facility at 2926 Piper Road in Vero
Beach, FL. In September 1975, Piper installed an
underground storage tank (UST) which was used to
store trichloroethylene (TCE). TCE was first placed
in the UST in January 1976. In October 1978, TCE
was detected in the City of Vero Beach municipal
water supply well (CVB #15), which is located
1050 feet southeast of the UST. It was determined
that the fitting on the tank had been leaking.
Use of well CVB #15 was discontinued after TCE
was detected, and two new municipal supply wells
were constructed. In 1979, a six-inch diameter
extraction well was installed adjacent to the UST
for the purpose of groundwater remediation.
Extracted water was discharged via a mile long
pipeline to a spray-header assembly installed across
a flood control canal. Initial pumping began in
April 1981. In October 1981, Piper signed a
Consent Agreement with the Florida Department of
Environmental Regulation for remediation of the
TCE contamination.
In October 1984, EPA conducted a Preliminary
Assessment of the Site. In June 1986, EPA
proposed the Site for inclusion on the National
Priorities List (NPL). hi March 1988, EPA
completed a Site Inspection of the Site.
In June 1989, Piper removed the UST as well as
contaminated soil surrounding the UST to a depth
of 14 feet below land surface. A total of 740 cubic
yards of TCE-contaminated soils were "land
farmed" with aeration for six weeks.
The Site was finalized on the NPL in February
1990. EPA completed the Remedial Investigation /
Feasibility Study (RI/FS), as well as Ecological and
Human Health Risk Assessments between April
1992 and December 1993. EPA issued a ROD for
the Site on December 23, 1993.
Site Contamination
The contaminants found at this Site were TCE, cis-
1,2-dichloroethene, 1,1-dichloroethene and vinyl
chloride in groundwater. Some or all of the
contaminants identified are hazardous substances as
defined in § 104(14) of CERCLA, 42, U.S.C. §
9601(14), and 40 C.F.R. § 302.4. At the time of the
ROD, as well as during the most recent sampling
event (December 2008), three of the four
contaminants had concentrations that exceeded
Federal and State Maximum Contaminant Levels
(MCL). The maximum concentrations detected
during September 1992 (as presented in the 1993
ROD) and December 2008 are presented in the
following table.
Contaminants of Concern
Trichloroethylene
cis-1 ,2-Dichloroethene
1,1-Dichloroethene
Vinyl chloride
MCL*
(M9/L)
3
70
7
1
1993 ROD
Maximum
Concen-
tration
300
730
2.6
30
2008
Maximum
Concen-
tration
20.8
105
2.7
192
* Note: The MCL value presented in this table is the more
stringent value when the Federal and State MCL values differ.
The Federal Safe Drinking Water Act MCL for trichloroethylene
is 5 ug/L. The Federal MCL for vinyl chloride is 2 ug/L. The
Federal and State MCLs are identical for cis-1 ,2-
dichloroethene and 1,1-dichloroethene.
IV. Selected Remedy
The Site was addressed as a single Operable Unit.
The ROD for the Site was signed on December 23,
1993. The results of the RI/FS and risk assessments
indicated that ingestion of contaminated ground
water posed a risk to human health. Soil, surface
water, and/or sediment did not pose a risk to human
health or the environment. Therefore, the ROD
selected a remedy for ground water.
The 1993 ROD presented the following as the
remedial action objective:
The ground water treatment component of
the selected remedy will protect human
health and the environment by reducing or
preventing further migration of the
ESD, September 2009, Piper Aircraft/Vero Beach Water & Sewer Superfund Site
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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 oflxlO'4 and
1x10' and the non carcinogenic risk would
be reduced to the EPA goal of I.
The remedy selected for the Site was Alternative 3 a,
Ex-situ Treatment of Groundwater with surface
water discharge. The remedy components included:
• Groundwater withdrawal using extraction
wells
• Treatment of groundwater via air stripping
• Discharge of treated effluent to surface
water
• If necessary, treatment of air emissions
The cleanup levels specified in the 1993 ROD are:
Contaminants of
Concern
Trichloroethylene
cis-1 ,2-Dichloroethene
1,1-Dichloroethene
Vinyl Chloride
Federal
MCL
(ug/L)
5.0
70.0
7.0
2.0
State
MCL
(M9/L)
3.0
70.0
7.0
1.0
(As of April 1, 2009, the Federal and State MCL
values for these constituents have not changed.)
V. Description of Significant
Differences and Basis for the ESD
The 1993 ROD evaluated several groundwater
alternatives which included:
• GW1: No Action
• GW2: Groundwater Use Restrictions
• GW3a: Ex-Situ Treatment with Effluent
Surface Discharge
• GW3b: Ex-Situ Treatment with Injection
Well Disposal
• GW4a: In-Situ Treatment (bioremediation)
with Injection Well Disposal; and
• GW4b: In-Situ Treatment, Gradient Control,
Ex-Situ Treatment with Injection Well
Disposal.
Alternative GW3a was selected as the remedy for
the Site.
Treatment System Modifications
The remedy selected by the 1993 ROD included
ground water extraction, treatment via air stripping,
discharge of treated water to surface water, and if
necessary, treatment of air emissions. EPA and
Piper entered into a Consent Decree in November
1995. Piper began the Remedial Design in
December 1995 and submitted a supplemental
Focused Feasibility Study (FFS) in June 1997.
Piper requested that EPA approve an alternate
treatment technology, which consisted of
proprietary in-well aeration/stripping system (UVB
Well). The traditional pump and treatment
technology includes pumping water from the
ground, piping it to a treatment chamber such as an
air stripper, and then piping the treated water to the
discharge location (e.g. surface water). The UVB
system eliminates the need for excess pumping and
piping. The UVB system pumps contaminated
water from the ground, treats the water with an air
stripper just below the ground surface at the
location of the well, and then pumps the treated
water back into the ground at that same location.
Because the UVB system was thought to be more
efficient than the traditional pump and treat
technology, EPA agreed to the proposal and Piper
continued with the Remedial Design.
Installation of the two UVB Wells (UVB-1 and
UVB-2) occurred in January 1998. UVB-1 was
installed near the original extraction well and
included an external air stripper, while UVB-2 was
installed at the south end of the property as
described in the preceding paragraph. The system
was deemed "operational" in October 1998,
although the flow rates for the return of treated
water to the aquifer were Vz and 1/3 the rate
estimated by the Remedial Design. Modifications
ESD, September 2009, Piper Aircraft/Vero Beach Water & Sewer Superfund Site
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were made to the system over the next few years to
improve the flow rates. Modifications included
installation of an external air stripper on UVB-2 and
piping the treated water from the UVB-2 air stripper
to the former extraction well for injection into the
ground. In addition, in 2001, UVB-1 was replaced
with UVB-1 a in hopes of increasing contaminant
recovery rates. UVB-1 a was located further east in
an area of higher volatile organic compound
concentrations.
Institutional Controls
The groundwater remedy selected in the 1993 ROD
does not include a requirement for Institutional
Controls (ICs). However, institutional controls
have been implemented at the Site. Because
hazardous substances, pollutants, or contaminants
are present in groundwater above levels that allow
for unlimited use and unrestricted exposure to
ground water, institutional controls are warranted
until CERCLA cleanup goals allowing unrestricted
use of the aquifer are met for the Site.
Under chapter 62-524 of the Florida Administrative
Code, if hazardous substances, pollutants, or
contaminants are present in ground water above
levels that allow for unlimited use and unrestricted
exposure to groundwater, Sites and a buffer area are
designated as a Florida Groundwater Delineation
Area. The contaminated groundwater plume and
the Delineation Area associated with the Site are
illustrated in the attached figure. Implementation of
the delineation rule is a cooperative effort among
the FDEP, the Florida Department of Health, and
the water management districts. The State water
management districts may require additional well
construction measures as part of the well permitting
process in areas delineated by FDEP. Each permit
application for a new well is reviewed to determine
the well's location relative to delineated areas. If
the well is located in a delineated area, the water
management district may require more rigorous
well construction specifications, a treatment filter
may be installed on the well, or connection to a
public water system may be necessary. More
information about Florida groundwater delineation
areas can be found at:
http://www.dep.state.fl.us/water/groundwater/deline
ate.htm.
In addition, Section 78-202 of the Municipal Code
of the City of Vero Beach, states
It is found and determined that it is necessary
for the health and welfare of the inhabitants of
the city that the owners or occupants of all
commercial buildings, individual residences,
condominium units, apartments, trailer parks,
mobile home parks, and modular home parks
and premises therein are required to connect
with and use the services and facilities of the
water system of the city for potable water needs.
(Code 1982, § 19.02; Ord. No. 97-14, § 1, 5-20-
1997)
The Site and surrounding area are located within the
city limits. The Municipal Code for the City of
Vero Beach can be found at:
http ://www. muni code, com/resources/gateway. asp?p
id=11654&sid=9
Institutional Controls will be enforced by the City
of Vero Beach and the State of Florida. EPA will
evaluate the effectiveness of the ICs during the
Five-Year Review process.
VI. Support Agency Involvement
In accordance with the NCP §300.435(c)(2), EPA
consulted with the FDEP prior to the issuance of
this BSD. EPA also provided FDEP with the
opportunity to comment on the draft ESD. FDEP
supports the issuance of this ESD and provided
comments on an earlier draft. Their comments have
been incorporated into this version.
VII. Statutory Determinations
EPA has determined that these significant changes
comply with the statutory requirements of CERCLA
§121, 42 U.S.C. §9621, are protective of human
health and the environment, comply with Federal
and State requirements that are applicable or
relevant and appropriate to the remedial action, are
ESD, September 2009, Piper Aircraft/Vero Beach Water & Sewer Superfund Site
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cost-effective, and utilize permanent solutions and
alternative treatment technologies to the maximum
extent practicable.
Because this remedy upon completion, will not
leave hazardous substances, pollutants, or
contaminants on site above levels that allow for
unlimited use and unrestricted exposure, but
requires five years or more to complete, a policy
review will be conducted no less often than each
five years after the initiation of the remedial action
to ensure that the remedy is, or will be, protective of
human health and the environment. The first Five-
Year Review was completed on May 14, 2004. The
second Five-Year Review was completed on May 5,
2009. Five-Year Reviews will continue until
cleanup goals have been attained.
VIII. Public Participation
The public participation requirements set out in the
NCP §300.435(c)(2) will be met by publishing this
BSD, making it available to the public in the
Administrative Record, and publishing a notice
summarizing the BSD in a major local newspaper.
EPA updated the Administrative Record in July
2009. The Vero Beach Press Journal published
EPA's ad on August 5, 2009, which announced the
availability of the updated Administrative Record
and that the draft BSD was available for public
comment at the repository listed in Section I. EPA
also mailed a copy of the draft BSD to addresses
within a half-mile radius of the Site.
EPA considered written comments, postmarked on
or before August 31, 2009, before preparing this
final version of the BSD. Two citizens of Vero
Beach submitted written comments regarding the
draft BSD during the comment period. One citizen,
whose deceased wife worked for Piper Aircraft in
the 1980s, stated that employees should have been
warned and protected from the effects of TCE. The
other citizen commented about the expense of
having to install a new well for residential irrigation
purposes and that some residents must pay City of
Vero Beach utility rates for water to irrigate because
they cannot install wells for any purpose due to the
ground water contamination. A third citizen has
been corresponding with EPA during the past few
years, but not regarding this BSD.
IX. Authorizing Signature
I have determined the remedy for the Site, as
modified by this BSD, is protective of human health
and the environment, and will remain so provided
the actions presented in this report are implemented
as described above. This BSD documents the
significant changes related to the remedy at the Site.
U.S. Environmental Protection Agency
By:
E. Hill, Director
& Superfund Division
Date:
ESD, September 2009, Piper Aircraft/Vero Beach Water & Sewer Superfund Site
Page 5
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LIST OF ABBREVIATIONS
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980
CVB City of Vero Beach
EPA United States Environmental Protection Agency
ESD Explanation of Significant Differences
FDEP Florida Department of Environmental Protection
FFS Focused Feasibility Study
ICs Institutional Controls
MCL Maximum Contaminant Level
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NPL National Priorities List
Piper Piper Aircraft, Inc.
RI/FS Remedial Investigation / Feasibility Study
ROD Record of Decision
SARA Superfund Amendments and Reauthorization Act of 1986
Site Piper Aircraft/Vero Beach Water and Sewer Superfund Site
TCE trichloroethylene
U.S.C. United States Code
UST underground storage tank
UVB Unterdruck-Verdampfer-Brunnen
ug/L micrograms per liter
ESD, September 2009, Piper Aircraft/Vero Beach Water & Sewer Superfund Site
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