PB94-964075
EPA/ROD/R04-94/208
February 1995
EPA Superfund
Record of Decision:
American Creosote Works
(O.U. 2), Pensacola, FL
2/3/1994
-------
»
RECORD OF DECISION
OPERABLE UNIT 2
GROUNDWATER REMEDIATION
. AMERICAN C~OSOTE WORKS, INC.
. Pensacola, Escambia County, Florida
~~EO sr4lf,.~
~ ,,~
~ft:u
S~~
~ ~
~ ~tt
~l. PR(j{f;~
Prepared By
Environmental Protection.Ag~ncy
Region IV
Atlanta, Georgia
-------
RBCORD OF DECISION.
OPERABLE CHIT 2
AMERICAN CREOSOTE WORKS, IRC. SI'1'E
I.
DECLARATION
SI'l'B NAME AND LOCATION
American Creosote Works, Inc.
. Pensacola, Escambia County, Florida
STATEMEN'1' OP BASIS AND PtJRPOSE
This decision document presents the selected remedial action for
Operable Unit 2 at the American Creosote Works, Inc. (ACW) site in
Pensacola, Florida, which. was chosef1, in accordance with the
C6mprehen.sive .Environmental Response, Compensation and Liability.
Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA),. and, to the extent practicable,
the. National Oil and Hazardous Substances Pollution Contingency
Plan (NCP). This decision is based on the Administrative Record
for the site.. .
The Floridg Department of Environmental Protection (FDEP) has
provided input .'as the support agency throughout the remedy
selection process. Based on.FDEP's comments to date, EPA expects
that concutrence on this remedy will be forthcoming, although a
formal concurrence letter has not yet been received.
ASSBSSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
su,bsta~tial endangerment to public. health, welfare,.. or . the
environment. .
DBSCRIPTION OF THB REMEDY
The remedy selected by EPA for the American Creosote Works site
will be conducted in two operable units. Operable Unit 1 addresses
contaminated soils and sludges which represent the source of
contamination at the site. Operable Unit 2, presented in this ROD,
will address groundwater contamination at the site.
. .' . .. '" '
The selected "remedy for Operable Unit 2 consists. of two phases.
The first phase, involving recovery and disposal of dense non-
aqueous phase liquids (DNAPLs), includes the following components:
o
Enhanced DNAPL recovery using a combination of water,
alkaline, surfactant, and polymer flooding
o
DNAPL/water separation and groundwater treatment
o
.Off-site transport and recycling of recovered DNAPL and
reinjection of treated groundwater"" ,
'1-
-------
o
per10dic groundwater
recovery efficiency
monitoring
to
evaluate
DNAPL
o
Sampling, plugging, and abandoning private wells
which owner consent 1S granted
for
o
Implementation of State-1mposed well permit restrictions'
Based on the results of periodic monitoring data compiled during
the five year review, EPA will determine whether to continue
enhanced recovery of DNAPLs or to implement the second phase of the
Operable unit 2 remedy to address residual groundwater
contamination in the aquifer. The components of this second phase
of the remedy are listed below: .
o
Groundwater removal V1a extraction wells
o
On-site treatment of contaminated groundwater
o
Nutrient and hydrogen peroxide addition to treated water
o
Reinjection of treated groundwater (including nutrients)
into the contaminated portion of the aquifer to stimulate
in-situ biological treatment activity
o
Dewatering of waste sludge from the treatment process and
disposal at an off-site RCRA landfill
o
periodic groundwater and surface water monitoring
evaluate treatment system performance
to
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-effect.ive. Th1S remedy utilizes permanent
solutions and alternative creatment technologies to the maximum
extent practicable and satisfies the statutory preference for
remedies that employ treatmenc that reduces toxicity, mobility, or
volume as a principal element.
Because this remedy may result in hazardous substances remaining in
the groundwater above health-based levels, 'a review will be
conducted every five years after commencement of remedial action to
evaluate syscem performance and ensure that the remedy continues to
provlde adequate protection of human health and the environment.
i'~fj; 3)/794
ate
~/YI~
~John H. Hankinson
, Reglonal Administrator
0.5. EPA Reglon IV
.L.L
-------
TABLB OF CONTENTS
DECLARATION. . .
.. . . .. ..
.. .. .. .. .. .. ..
. .. .. ..
OJ .. .. ..
Table of Contents
.. .. .. .. ...
.. .. .. .. ..
. . .
.. .. .. ..
.. .. .. ..
, ,
List of Figures
.. .. .. ..
.. .; .. ..
.. .. .. .. ..
. . .
. . .
.. .. .. ..
List of Tables
. . .
.. .. .. .. ..
.. .. .. ..
. . .
.. .. .. ..
.. .. .. ..
II.
DECISION SUMMARY
.. .. .. ..
.. .. .. ..
1.0
.......
.. .. .. ..
. . .
SITE N~, LOCATION, AND DESCRIPTION. .
........
3.0
2.0 ,SITE HISTORY AND ENFORCEMENT ACTIVITIES
HIGHLIGHTS OF COMMUNITY PARTICIPATION
. . .
....e..'...
4.0
5.0
6.0
7.0
. . .
.. .. .. .. ..
SCOPE AND ROLE OF OPERABLE UNIT
.. .. .. ..
e.. .. .. .. .. .. ..
SUMMARY OF SITE CHARACTERISTICS. . . . " . . . . . . .
5.1 General Site Characteristics. . . . . . . . . . .
5.2 Results of Groundwater Investiqations . . . . . . .
SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . . .
6.1 Human' Health Risks. . . . . . . . . . . . . . . .
6.1.1 Contaminants of Concern. . . . . . ., .' .
'6.1.2 Exposure Assessment. . . . . . . . . . .
6.1.3 Toxici tv Assessment. .'. . . . . . . . .
6.1.4, Risk Characterization. . . . . . . . . '.
6.1.5 Uncertainties in the Risk Assessment
6.2 Environmental Risks. . . . ,. . . . . . . . . . . .
DESCRIPTION OF ALTERNATIVES. . . . . . . . . . . . . .
,7.1 Alternative DN1 - No Action. . . . . . . . . . . .
7.2 Alternative DN2'''; DNAPL Extraction; On-site
Thermal Treatment' . .' '.. . . . . . . . . . ',' ..
7.3 Alternative DN3A - DNAPL Extraction; Off-site
Trea tmen t . . . . . . . . . . . . . . . . . . . . .
Alternative DN3B - DNAPL Extraction; Reevclinq
Alternative GW1 - No Action. . . . . . . . . . . .
Alternative GW2 - Groundwater Use' Restrictions and
Monitorinq . . . . ',. . . . . . . . . . . . . . .
7.7 Alternative GW3A - Extraction and Treatment;
Surface Water bischarqe . . . . . . . . . . . . . .
: 7.8 Alternative GW3B '- Extiaction and Treatm~rit;
Reiniection . . . . . . . . . . . . . . . . . . . .
7.9 Alternative GW4 - In-Situ/Ex-Situ Bioremediation
7.4
7.5
7.6
8.0
COMPAR~TIVE ANALYSIS OF GROUNDWATER AND DNAPL
ALTERNATIVES. '.'. . . . . . . . . . . . . . .
8.1 Overall Protect-lOD of Human Health and the
Environment. .... ......,
. .. .. .. ..
.. .. .. ..
L ~. -:
i
. iii
v
vi,
1
1
1
5,
6
7
7
9
11
11
11
14
17
22
26
27
28
29
29
30
30
31
33
33
35
35
37
38
-------
9.0
10.0
11. 0
8.2
8.3
8.4
8.5
8.6
8.7
8.8
8.9
Compliance with ARARs . . . . . . . . . . . . . . .
Lonq-Term Effectiveness and Permanence. . . . . .
Reduction of Toxicity, Mobility, or Volume throuqh
Trea tmen t . . . . . . . . . . . . .. . . . . . . . .
Sh0rt-Term Effectiveness. . . . . . . . . . . . .
Implementability . . . . . . . . . . . . . . . . .
Cos t . . . . . . . . . . . . . . . . . . . . . . .
State Acceptance. . . . . . . . . . . . . . . . .
Community Acceptance. . . . . . . . . . . . . . .
SELECTED REMEDY. . . . . . . . . . . . . . . . . . . .
9.1 Remedial Action Obiectives . . . . . . . . . . . .
9.2 Performance Standards. . . . . . . . . . . . . . .
STATUTORY DETERMINATIONS. . . . . . . . . . . . . . . .
10.1 Protection of Human Health and the Environment
10.2 Compliance with Applicable or Relevant and
Appropriate Reauirements (ARARs) .........
10.3 Cost Effectiveness. . . . . . . . . . . . . . . .
10.4 Utilization of Permanent Solutions to the Maximum
Extent Practicable. . . . . . . . . . . . . . . .
10.5 Preference for Treatment as a Principal Element. .
DOCUMENTATION OF SIGNIFICANT CHANGES
. . .
. . . . . .
Appendix A - Dloxin Toxicity Equivalence Factors
III. RESPONSIVENESS SUMMARY
l- \'''
39
39
40
40
41
41
42
42
42
49
50
52
52
53
54
54
54
55
-------
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
LIST OF PIGORBS
General Site Location Map
........
. '.' . . .
Shallow Zone Contamination Above Remedial Goals. .
Intermediate Zone Contamination Above Remedial
Goals. . . . . . . . . . . . . . . . . . . .
. . .
Deep Zone Contamination Above Remedial Goals
. . .
Groundwater Treatment System ,Schematic
. . .
. .. .
Conceptual Groundwater Extraction and Reinjection
Scenario. . . . . . . . . . . . . . .' . 0 . . . .
v
Paqe
2
10
12
13
44
48
-------
Table 1
Table 2
.Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
LIST OF TABLES
Contaminants of Concern and Exposure Point
Concentrations. . . . . . . . . . . . . . . . . .
Exposure Assumptions for Future On-site and Off-site
Residents Exposed to Contaminated Groundwater. . .
Daily Intake Formulas. . . . . .
. . . . . .
. . .
Toxicity Values for Contaminants of Concern.
. . .
'Individual Risks Associated with Contaminants of
Concern. . . . . . . . . . . . . . . . . . . . . .
Summary of Future Cancer Risks
. .. . .. . . .. .. .. .
Summary of Future Hazard Quotients
. . .
.. ... . . .
Groundwater Remedial Goals
. . . . .
.. . . .. . .. .
Surface Water Quality Standards and MCLs for
Contaminants of Concern. . . . . . . . . . .
. . .
- ~
Paqe
15
18
19
20
23
25
25
32
45
-------
II.
DECISION SUMMARY
1.0
SITE NAHB, LOCATION, AND DESCRIPTION
The American Creosote Works, Inc~ (ACW) site occupies 18 acres in
a moderately dense commercial and residential distriGt in
Pensacola, Florida. The site is loc~ted about one mile southwest
of the intersection of Garden and Palafox Streets in downtown
Pensacola and is approximately 600 yards north of Pensacola Bay and
Bayou Chico. Immediately north of the site is a lumber company, an
auto body shop, an appliance sales and repair shop, and a wire
storage area. The Pensacola Yacht Club is- southwest of the site.
Residential neighborhoods are immediately adjacent to the site on
the east, and south, with the, nearest residence, located
'approximately 50 feet from the site boundary. A general site
location map is provided as Figure ,1.
The ACW site is nearly' flat, with elevations ranging between 12,and
14 feet above sea level. The land slopes gently southward at about
25 feet per mile toward Pensacola Bay. The site is about 2,100
feet long, east to west, and an average of 390 feet wide, north to
south. Primary access to the plant is from Barrancas Avenue.
Originally,- a railroad spur line of Burlington Northern Railroad
traversed the plant from, west to east. ~he, majority of site
buildings, process tanks, and equipment were situated near the
cent'er of the site in an area designated as ,the main plant area.' '
A few small work sheds, ,miscellaneous equipment, 'and debris were
situated around the remainder of the site. The railroad spur and
all of the process equipment and buildings have been removed. At
present, only the main building foundation and approximately 200
drums containing investigation-derived wastes, remain on-site.
2.0
SITE HISTORY AND ENFORCEMENT ACTIVITIBS
Wood-preserving operations were carried out at the ACW site from
1902 until December 1'981.' Prior to 1950,' creosote was used
exclusively to treat poles. Use of pentachlorophenol (PCP) started
in 1950 and increased in the later years of the ACW operations.
Four formeL' surface impoundments were located in the western
portion of the ACW site. The Main and Overflow ponds, located
adjacent to "L" Street, were used for disposal , of process wastes.
During its years of operation, ACW discharged liquid process wastes
into the two unlined surface impoundments. Prior to abo1,lt 1970,
wastewaters in these ponds were allowed to overflow through a
spillway and follow a drainage course into Bayou Chico and
Pensacola Bay. In subsequent years, liquid wastes were
periodically drawn off the larger lmpoundments and allowed to
accumulate in the smaller Railroad Impoundment and Holding Pond, or
were. spread. ouc on the designated "Spillage Area" on-site.
Additional discharges occurred durl.ng periods of heavy ralnfall and
t loading,' ','Jhen the ponds overt lowed :.he concainment dikes.
1
-------
, ,
! ,
.-..-.- ,
.. .,.--.-
._.. ---..
-.---~
. ..
4_.__'_-".--'
.. . -.. .......--
. . ._0.- .h
.-. .. --...- ".--. ...
.._..~ .... .-..-' .. .
. -'
-----..-..-------'
-:
tll
w' :
:::: :
tJ j
~ .-.
PE~:3ACOU.,
YACHT CLUB
PROPERTI' ---
I
-'
.......j
v:
E-i
25:
I
w:
vi
..... :
.z
~
c::
Q,
. 1
1;;'
:Ł;1
.:r::!
:J~ :
, ,
....,.,......'
.....- ..",,'
. -
- .
. ..
,.
.. ..-
--_:.: <:l- -
~~,'.y..
. ~'.'
.-..'
.'
). \\;-.. "\
,.(,0\."
.-:>;
\)~>. .
- "-
-.-...-
A:\ W,t:
("I{JeG
t
.' .'
LF.Gf.:"\D
i''<.)l':~:L:l': :.'U1L)(.a: !'O:-J)~:
CHo\l\ :.INf-: n:Nn: ""
::rn: \.1'01 \i)o\l~) ............---
I )j~1 \' :' 'Ol<.\(;\: \I~I:" .::.:'.,.
:(:;rNnrr, ,:'1 !',)(.r ,\r:f,\ ..
It' .f'
';'~T T,-' ",~.-\!.r
.. - .-_. ---- - -.-... .._'..-
- -.----. .._-------
'-----"'---
ŁEPA
(:L.:"t-:lU.L SI n: 1..\ YO'''!'
. \!\ll:.k!< '.\\ ("kEOSf) II:. \\'okh:s. 1\('.
l'I'-':o.ACOI..\. II.
FI(;I In: I
~
-------
In March 1980, the City of Pensacola found considerable quantities
of an oily creosote-like material in the, groundwater near the
intersection of ALR and Cypress Streets. In July 1981, the u.S.
Geological Survey (USGS) installed nine groundwater monitor wells
in the vicinity of the ACW site. Samples taken from those wells
revealed, that a contaminant plume was moving in a ,southerly
direction toward Pensacola Bay. In October 1981, EPA proposed the
site for inclusion on the National Priority List (NPL) , a list of
abandoned or unregulated hazardous waste sites eligible, for
attention under the CERCLA long-term cleanup program. The site's
listing was finalized on September 8, i983.
In February 1983, EPA conducted an investigation which included
sampling and analysis of on-site- soils, wastewater sludges,'
sediment in area drainage ditches, and existing groundwater from
on-,site and off-site monitoring wells. , Analytical results
, indicated that 'the major contaminants in the groundwater and on-
site soils were polynuclear aromatic hydrocarbons (PAHs), which are
common to creosote. Among the various surface water and ,sediment
locations that were sampled, only the drainage ditch on the
Pensacola Yacht Club (PYC) property showed contaminants associated
with theACW site. Analytical'results indicated that inorganic
contaminants were not present in signifi~ant concentrations.
Beca~se of the threat posed to human health and the environment by
frequerit overflows from the waste 'ponds, the EPA Region IV
Emergency Response and Control Section performed an immediate
cleanup during September to October 1983. The immediate cleanup
work included dewatering the two large lagoons (main and overflow
ponds), treatment of the wastewater, and discharge to the City of
Pensacola sewer system., The sludge in the lagoon was, then
stabilized with lime and fly ash, and a temporary clay' cap was
placed over the stabilized material. The Florida Department of
Environmental Regulation (FDBR), the predecessor agency to FDEP,
also assisted during the ~leanup. , '
In' 1985, EPA completed a remedial investigation and feasibility
study (RI/FS) under CERCLA. Samples were collected' from local
surtace water, sediment, existing USGS monitor wells, residential
wells, newly installed monitor wells, and on-site and off-site
surface soils. Analytical results indicated that on-site and off-
site surface soils, the drainage ditch on the Pensacola Yacht Club
property, and groundwater were contaminated with PARs, phenols, and
volatile organic compounds. '
. . . .
Based on this study, EPA signed a ROD in September 1985 which
selected a remedy for all on-site and off-site contaminated surface
soils, sludges, and sediments to be placed in an on-site hazardous
waste landfill. Groundwater remediation was not included.
However, the State of Florida did not agree with this decision,
citing the need for additional information. Consequently, EPA
inltiated another study In 1986 (known as the Post-RI) to provide
furthe:::- informatlon on the exr:.ent' of contamination In' surface
3
-------
soils. Over 125 organic compounds were detected on and around the
ACW site during this investigation. Indicator groups of
contaminants were selected to simplify the data discussion. These
incl uded carcinogenic PAHs, noncarcinogenic PAHs, phenols,
pentachlorophenol, dioxins/dibenzofurans, and phthalates.
Following the Post-RI, EPA prepared a revised risk assessment and
a supplemental alternatives evaluation (the Post-FS) and selected
a new cleanup remedy in September 1989 which called for
bioremediation of surface soils. The ROD specified that
treatability studies would be conducted during the design phase to
determine the most effective type of biological treatment. These
studies demonstrated that bioremediation would not be effective for
addressing all contaminants in site soils, so EPA anticipates
selecting another remedy in a ROD amendment in 1994.
In March 1990, EPA completed Phase II of the Post-RI which
addressed contamination in groundwater, solidified sludge, and
subsurface soils. A total of 63 samples were collected including
23 groundwater samples, 17 sediment samples, 15 subsurface soil
samples, and 8 surface soil samples. The groundwater, sediment,
subsurface soil, and one surface soil sample were analyzed for
purgeable and extractable organic compounds. Seven on-site surface
soil samples were analyzed for total dioxins. Results of the
analyses iridicated the presence of elevated concentrations of
numerous organic compounds and dioxins in one or more environmental
media (soil, surface water, groundwater, or sediments) . .
EPA completed Phase III of the Post-RI in January 1991 to further
characterize and verify the extent of organic contamination in the
groundwater and dioxin contamination in the on-site and off-site
soil (down to a depth of 18 inches). During this investigation, a
total of 16 samples were collected including 4 groundwater samples,
8 on-site soil samples, and 4 off-s~te surface soil samples. A
variety of organic compounds and dioxins were detected.
Finally, EPA conducted a focused groundwater investigation (Phase
IV) in May 1993 to evaluate the presence of dioxin in groundwater.
Samples were collected from 10 wells screened in the shallow,
intermediate, and deep zones of the aquifer along the axis of the
known contaminant plume. Dioxins were detected at very low levels
(0.0092 ng/l TEQ) in only one well completed in the deep zone
directly beneath the site.
EPA completed a Baseline Risk Assessment in August 1993 to evaluate
potential risks associated with groundwater, sol~dified sludg~, and
subsurface soils. A summary of the r~sks associated with
contaminated groundwater at the s~te ~s presented in Section 6.0.
Enforcement Summary
The earlies~ documented lncident 8t a ~elease of a~y type from the
;',C7,; pL:irl~ ccc.Jr~ed i:1 the sumrner 8: l:178, ',.;hen a spill 8f liquids
~
-------
flowed onto a nearby street and then onto the property of a yacht
sales company. A flood in March 1979 resulted in a similar spill.
These incidents 'resulted in increased regulatory attention to ACW
by FDER. '
In 1980, ACW filed an incomplete, application' with FDER for
construction of an industrial wastewater treatment system.FDER
issued a Notice of Violation (NOV) for corrective action in 1981,
alleging contamination of soils and groundwater. This enforcement
action called for ACW to cease operations until a permit was
issued, submit a restoration plan, install a groundwater monitoring
system, and remove contaminated soils. In January 1981, FDER
completed a responsible party search', a title search, and a
financial assessment for the site, and in March 1981, FDER and ACW
entered into an administrative consent order which incorporated the
pz;-evious NOV requirements and allowed' A,CW, tocontinueoperat'ions.
The Order included schedules for completing construction of the
wastewater treatment system and meeting the other NOV requirements.
Throughout 1981 and 1982, FDER encountered difficulty with ACW's
compliance efforts, and in March 1982, ACW announced that
environmental regulations were forcing the company to go out of
business. As a result, FDER filed a petition for Enforcement and
Agency Action and a Complaint for Permanent Injunction and Civil
Penalties in April ,1982 because of ACW's failure to make progr~ss
toward' compliance ~ 'One' month lat~r. in May '1982, ACW, Inc. of
Florida filed for reorganization in bankruptcy court. ' In 1984,' the
court presented a final court stipulation for the approval of the
litigants. The stipulation provided that half of the proceeds of
any sale or lease of the ACW property would go to EPA and FDER.
The remaining 50 percent would go to Savings Life Insurance Company
which holds a mortgage on the property in the principal sum of
$675,000. The stipulation was finalized and entered by the court
in 1988.
In 1985, EPA sent a notice lettei to Burlington North~rri Railroad
raquesting removal of a railroad spur line along their right of way
on the site. The railroad company completed this work in 1986.
3.0
HXGHLXGHTS OF COMMONXTY PARTXCXPATXON
In accordance with Sections 113 and 117 of CERCLA, as amended, EPA
has conducted community relations activities at the ACW site to
solicit community input and ensure that the public remains informed
about site activities. EPA has relied, on a number of methods for
keeping 'the public informed, including press releases, fact sheets;
public meetings, establishment of an information repository, and
public comment periods.
EPA's earliest community outreach effort was a press release
related to the emergency removal activities in 1983. Periodic fact
sheets were issued during 1984 and 1985 to update the community
c:oncer:ll:1g scudies being conducted at the slte. In September 1985,
J
-------
EPA issued fact sheets and press releases announcing a public
meeting and comment period related to the proposed plan for
addressing source contamination at the site. Similarly, in 1989,
EPA issued a fact sheet and held a public meeting to discuss the
revised source control remedy. In 1990, EPA prepared an
Explanation of Significant Differences (ESD) notifying the public
of additional tasks that would be necessary to implement the 1989
ROD. Later, in March 1991, a fact sheet was published to advise
the public of the initiation of these site preparation activities
which included cap repair, drum characterization, fence repairs,
well closure, and building demolition.
More recently, EPA conducted a door-to-door survey in September
1993 in the neighborhood surrounding the site to update its mailing
list. EPA's Proposed Plan for Operable Unit 2 was sent to the
public in November 1993, and the administrative record for the site
was made available in the public repository at the West Florida
Regional Library. A notice was published in the Pensacola News
Journal on November 28 and 30, 1993 advising the public of the
availability of the administrative record and the date of the
upcoming public meeting. On December 2, 1993, EPA held a public
meeting to answer questions and receive comments on EPA's preferred
alternative for addressing groundwater contamination at the site.
A public comment period was held from November 12, 1993 to January
II, 1994, -and a response to any significant oral or written
comments received during this period is included in the
Responsiveness Summary in Section III of this ROD.
This decision document presents the selected remedial action for
contaminated groundwater at the ACW site in Pensacola, Florida,
chosen in accordance with CERCLA, as amended by SARA, and to the
extent practicable, the NCP. This decision is based on the
Administrative Record for the site.
4.0
SCOPE AND ROLE OF OPERABLE UNIT
As wlth many Superfund sites, the problems at the ACW site are
complex. As a result, EPA has organized the remedial work into two
smaller units, referred to as operable units. Operable Unit 1
addresses contaminated soils and sludges which represent the source
of contamlnation at the site. Operable Unlt 2, presented in this
ROD, will address groundwater contamination at the site. The
selected remedy for Operable Unit 2 will be conducted in two
phases. The first phase will lnvol ve recovery apd disposal of
DNAPLs, and the second phase will lnvolve remediation of dissolved
contamination in the groundwater. The selected remedy is
consistent with plans for future work to be conducted at the site.
In 1989 I EPA selected bioremediation for cleaning up on-site
surface soil contamination. However, following further testing of
t::his cechnology, EPA determined this remedy might not be fully
e~feCtlVe for all contaminaClon in site surface sOlIs. Therefore,
~?A plans to issue an amended PO~ fo! 2perable ~nit 1 in 1994 which
.:
-------
selects a more suitable remediation strategy. This amended ROD
will also address subsurface soil contamination and solidified
sludges.
5.0
SOKKARY OF SITB CHARACTERISTICS
5.1
General Site Characteristics
Pensacola lies within the Coastal Lowlands., or subdivision of a
major physiographic division of t~1e United States known as the
Coastal Plain Province. The Coastal Lowlands are relatively
undissected, nearly level, and lie about 100 feet or less above sea
level. The only distinctive topographic features of the Lowlands
are the step-like Pleistocene marine terrac'es, which descend from
the north, southward to the coastline. The area is situated on a
somewhat hilly, sandy slope which borders Bayou.Chico and Pensacola
'Bay. The bay is separated from the Gulf of Mexico by a long narrow'
island that forms a natural breakwater for the harbor. Most
surface water drainage in the area is by overland sheet flow
through the streets and storm drains south of the site'to Pensacola
Bay, and by way of the drainage ditch on the Yacht Club property.
The Gulf of Mexico, situated about 6 miles south of Pensacola Bay,
moderates the climate of Pensacola by tempering the cold northern
winds of winter and causing cool sea breezes during the. daytime in
summer. The average temperature for the summerrnonths is around 80,
degre'es with an average'daily range of 12.5 degrees.. . Temperatures
of 90 degrees or higher occur on an average of 39 times yearly. A
temperature of 100 degrees or higher occurs occasion,ally. The
average winter temperature is in th~ low to mid 50s with an average
daily range of 15.7 degrees. Severe cold waves are in~requent.
Ra~nfall is usually well distributed through the year with the
greatest frequency normally being in July and August. The greatest.
average monthly rainfall. occurs in July, and the lowest occurs in
October. . Serio~sly dest~~ctiYe hurricarte~ are' occasiortally
experienced in the vicinity.. Hurricanes historica'lly occur from.
early July to mid-October.
The groundwater in the vicinity of the ACW site contains three
major aquifers: a shallow aquifer which is both confined and
unconfined {the Sand-and-Gravel Aquifer), and two deep confined
aquifers (the upper and lower limestones of the Floridan Aquifer) .
The Sand-and-Gravel Aquifer and upper limestone of the Floridan
Aquifer are separated by a thick $ection of relatively impermeable
clay called the Pensacola Clay. . ".
The Sand-and-Gravel Aquifer is the only freshwater aquifer in
central and southern Escarnbia County and is the source of public
water supply for the area, including the City of Pensacola. The
aquifer is exposed at the surface throughout Escarnbia County and
deepens to as much as. 1. lOa feet thick.. It extendi north and west
7
-------
frQm Pensacola into Alabama and is recognized as far eastward as
the Chactawhatchee River (about 78 miles) .
The water bearing zone underlying the ACW site area is composed
primarily of sand with many interbedded layers and lenses of clay
and sandy clay. These clay layers and lenses range from less than
an inch to approximately 38 feet in thickness. Based on
characteristics of the sands in these areas, the water-bearing zone
can be divided into two distinct strata. The sand in the upper 25
feet below land surface (b.l.s.) of sediment varies in ~rain size
from fine to coarse and in density from loose to dense. These
variations in grain size and density are important, since these are
a factor in the seepage rate of water through the sediment.
The sand at depths greater than 25 feet b.l.s. to a depth of about
200 feet is predominantly a very dense sand, usually fine to medium
grained, with variable amounts of silt. Discontinuous clay and
sandy clay nodules and lenses occur throughout the deep sand. No
stratigraphic correlations can be determined between the clay
lenses found in the various borings.
Two massive clay formations exist in the water-bearing zone in the
site area. One clay layer lS directly under the ACW ponds at a
depth of abQut 100 feet b.l.s. This clay appears to be continuous
under the ACW pond area, although it does pinch out south of the
site. South of the site, a second maSSlve clay layer approximately
38 feet thick underlies the Pensacola Yacht Club property at a
depth of about .20 feet b.l.s., and extends south to the Pensacola
Bay. This second clay pinches out before reaching the ACW site.
There are three recognizable geologic subunits within the Sand-and-
Gravel aquifer in the site area. The uppermost subunit includes
the terrace sands, with shallow wells to approximately 25 feet
b .1. s., which provide relatlvely small yields of less than 50
gallons per minute (gpm). The middle subunit includes the
Citronelle Formation, where water supply wells extend 50 to 150
feet b.l.s. in depth, and have Ylelds ranging from 50 to several
hundred gpm. The lowest subunlt lncludes the Miocene Coarse
Clastics and the lower portlon of the Citronelle Formation, where
wells are over 200 feet b.l.s. In depth and have yields ranging
from 1,000 to 2,000 gpm.
Water-level measurements from wells lnstalled north of the 20-foot
deep clay layer to depths of less than 100 feet indicate that the
groundwater within the upper 100 feet is unconfined. Water-levels
from 20-foot deep and 60~foot deep wells indicate similar
groundwater elevations. South of the site where the 20-foot deep
clay layer is present, water levels below the clay layer show
groundwater elevations 0.5 to 3 feet higher than groundwater
elevations In the sand overlying thls clay layer. This difference
in hydraulic head indicates that groundwater below the 20-foot clay
layer is confined. This water-level difference also suggests that
3n upward gradient exists. The ult~illate fate of groundwater below
~
-------
the 20-foot clay is upward migration to the overlying sand and
discharge to Pensacola Bay and Bayou Chico. The groundwater below
the 100-foot clay is also under water-table conditions, with little
difference between wells above and below this clay layer. This
deeper clay contains profuse layers and lenses of clayey sand which
allow hydrologic communication between the two sand units.
The direction of groundwater flow is to the south with discharge to
Pensacola Bay. Portions of the shallow groundwater appear to
discharge to a drainage ditch on the Pensacola Yacht Club property,
which subsequently drains into Pensacola Bay at the mouth of Bayou
Chico. The aquifer is recharged by local rainfall, with relatively
high infiltration rates because of the sandy nature of the aquifer
apd overlying soils. Annuai recharge is 0 to 10 inches per year.
There are no public water supply wells in the immediate vicinity of
the ACW site, making this portion of the Sand-and-Gravel aquifer a...
Class G-II groundwater under Florida Administrative Code (FAC) 17-
520.410.. The nearest well field belongs to the City of Pensacola,
located approximately a mile north of the site. The cones of
influence of these wells do not reach the ACW site, and these wells
are not affected by site contamination. The People's Crystal Ice
Company, located upgradient of the site at 1511 W. Government
Street, does operate a well for ice production. Samples were
collected from a nest of wells near the ice company well, and
results indicated the presence of. very low levels of phenol to a
depth of 100 ft. However, the well is 190 ft. deep, and it is
sampled annually to comply with permit requirements.
5.2 Results of Groundwater Investiaations.
In order to facilitate discussions of groundwater contamination at
the ACW site, EPA refers to three zones within the Sand-and-Gravel
aquifer known as the shallow zone, intermediate zone, and deep
zone. The shallow zone represents groundwater at depths of up to
3.0 feet b.l. s. .' The intermediate zone extends from 30 feet to 7.0
feet b.l.s., and the deep . zone . includes groundwater at depths
greater than 70 feet. These zone descriptions have no geologic
significance, but they provide a convenient way of referencing data
from specific depths within the aquifer.
Contaminat~on in the shallow zone appears to be limited to the area
below and immediately downgradient of the ACW site. The primary
sources of this contamination were the four fOrmer wastewater
lagoons. on the ACW property. Although EPA drained these lagoons,
s.tabilized the sludges, and' placed a clay cap over 'the stabilized
material in 1983, these concentrated wastes may continue to 'serve
as a contaminant source for the shallow groundwater. Volatile
organic compounds (VOCs), phenols, and (PAHs) were detected in
wells installed ~n this zone. EPA also observed a separate DNAPL
layer of oil and creosote in this zone. The limits of
contamination in the shallow zone above remedial goals is
illustrated In Figure 2. .
9
-------
,.,.,
, , : ': ;,.:::: ;~~"".', i l.._,_,! L._~
'dO,: ,?«,::::,::::,/ ': I ',',- -il' .. i !"" -j
.=- 1>-:>/' ! ! : I j ;
..-,I.\~:-", ..:.'_----------..; ~_....: MAIN i L;:ITlili...EJJ
"""~"'-'Ly >~:~ I' I' Ii [
. . ,.' -.., '''''., .,11" '"i--...~
,',.' ': . <:.,-:.<,., ,":_"";.,:::,~::~::~,~--- : ' t>lMBLE ~IRE1:.'" :
~ "'" -.... ,. ..._---_._----.._,
~:... "''''''''
, ~":! -""'....
:-; I' '.. ~ (}lijt:;.."'I.l)f1JltA.~
~'. _d_~'7-'----"-"~-; ,
'I ' :~~() .'
j, A"- -' - - -,- """~':-...,~lL';~:':::'-:::-~d .-.d" .....-.-,'-----
~ ;,-
: ;
: ~
" ,
:,:
'.. ....-...,'-.
"-'.. .. .,-
- -
",\ 11':; A - ,- I
":::, l :'.
'," ': - .. .-' ...;.. ..:'
,. ".. .---...:. ,- :.--~"': ~ ,,-.. -- .
""04 ".I_~.. ..1-
- _._,' ~_.-
P~E
S':REET
~:tI'R~~~ ,-~-:!:.~'!' ,--
'n__::s..o.~lA ..
l""'--" --~ ;. ---.._-~ r"
: I '
I ~-r",,::.:
-'~-- ,.."_._-~
-----..---
.----, .
520 A
~\
3;::
~! !
::::! ~
'J:.
::::
7~~(} A.
I
I
I
I
,
I
L
'J.
. ~'
. ':.
'" - - - -
, ,
'.'
. .
K\W)['---- -
(' 111 CO
I.,
L
,-I
i.H;f-:l\1J
A
Pf'::-::=-:r\('(I!..l, nAY
~n..\1.{/'" ""7:J.
~'t;N', ~
.,.rrr.'-':oJY.A:1: "E~E['Il~7!"':-; [I'-"'~".U:Y
""1[' 1:N'Z:;Fr,'~;
; ',~. "\."',1'.,\.\':',': r \I"t- I" 1'01'.,' \' I.-
N' a: ,", \j~'. ',I .: :!" n! t:": ~)O"l ~.,
h:,"'.T ",:"1.'
'. 'II
~
'..
-I-
EPA
SII \!.I.OW t.O'"
t 0'1 \'''''\110' ,\110\"
In \,"-,)1.\1, (~o.\!.s
\\'1::,:1 .,. f:r(j-:I':'[' W:II,:<-
i " ~'~ :, L I I: ,,\, i 'I '
I'':''
FJ(;I'RF 1
1l;
-------
The intermediate zone appears to have the highest level of
contamination. The highest contam1nant concentrations were
detected on-site immediately downgradient of the former sludge
ponds. VOCs, phenols, and PAHs were detected at levels above
standards protective of human health. VOCs, phenols, and PAHs were
also found in significant concentrations. off-site in the.direction
of groundwater flow. The contaminant plume containing these
compounds has extended past Sonia Street, and it is approaching
Pensacola Bay. A DNAPL layer was also observed in this zone. The
extent of contamination above remedial goals in the intermediate
zone is illustrated in Figure 3.
PAHs, VOCs, and phenols have also been detected in significant
concentrations in the deep zone. However, VOC/phenol contamination
has migrated furtner downgradient than PAH contamination. The
majority of the PAR contaI!\ination was. found on~site and immediately
downgradient from the site. .In' contrast~ . VOC and .phenol
contamination was detected in a well just north of Pensacola' Bay
and Bayou Chico. The extent of contamination above remedial goals
in ~he deep zone is illustrated in Figure 4.
Based on the data available to date, EPA estimates that 152 million
gallons of'groundwater will require treatment. While 7.25 million
gallons of DNAPL are estimated to be present in the saturated zone,
EPA'expects"that only 2 million gallons (approximately 30 percent)
of this' material can be recovered. However, further investigations
will be necessary during the design to refine these volume
estimates. .
6.0
SOHMARY OP SXTB RXSKS
6.1
Human Health Risks
In . order to evaluate. whether existing or future exposure to
contaminated groundwater could pose a risk to people or the
envl.rorirnent, EPA completed a Baseline Risk Assessment (BRA) in
.August .1'993. In estimating potential site risks, EPA 'assumed no
further action would be taken to address contamination at the site.
This evaluation then served as a Qaseline for determining whether
cleanup of each site media was necessary. In the BRA, EPA
evaluated site risks for several environmental media. However,
this ROD addresses only the risks attributable to chemicals in the
groundwater at the ACW site. The r1sk assessment included the
following major components: contaminants of concern, exposure
assessment, toxicity qssessment, and risk characterization.
6.1.1
Contaminants of Concern
Chemlcals are included in the SUmmary of Site Risks section as
contaminant s of concern if the results of the risk assessment
indicate that the contaminant might pose a significant current or
future !"lsk. Contaminants of concern are those compounds that
contribu:e' co a pathway that exceeds a lxlO''; risk or a Hazard Index
1 ,
~ -..L
-------
, ,I,
~ : ,;
:: i\
('f.H!INO"t,NI' "'Alrsi' I : ."" '".,., ,i
Iit:N'I.t:NN I I ~ .' ,." , ,
7\' ! ';"'/:/j (~,"~CoJ i
. 4 ..-, ..._..",......__.,~'.~'" : ;1
. \ ~! :."~:,,.;",,. : 1 !
~(,~/" -~'-' ,,: I
, ~~~,.-.:: . ----
i ~,~~--:....\- I " r
, ----- .,' . ACENAI tlTHJOIE \
i . .-.-" L tUJORA.'llTHENE ,
,,/ ~--- .' DIBEN'ZOfURAN
"..',./1 ' ~. NtJ'tmWENI'
, ",' ~. '., ,CAR("II'~E:-;J(' Noll', ,
-----, . <~c:- \,~,<-;~ - .,~- "'~ :'~ " . ',",~, GI~1.E -::':""!:L\ I
" .. ..
" ," '\ .& .
:300.,,' :'~4-0..-.-" \\ .
, 0"'" ~. .~
?-"" ,'- ----Jr~:=~"'--~'piNE-: iFRi= 'j f.
II' ' ' '
: ".. ' ., 1\", d' ,.. ,C~~~!~~:: ~E~~--. :,
4--tOa!) , ::\\' " .~[lIRFJJ;~:I!.~ ,m. 'I j"""--'--'---lr
,." '''11'
, I
:\ J I
..--.-1 L._.,,- \
--"--li' '----1'1
i! I'
; I
MAIN I ! STREET L
--------..'
... . -..--
<~:~, l' /; ~'
,.--= -~ -:";-.. .---. ----'
, ----- j':,i ..... ~
flm~'Q~~[~~~~ ~ ~.:,'.~" :
", II :360 0
! \1 -400
I i\~ ,
". 7GO~;
.' -_.._._..~-~..... 0"'-'
..J
,:;:Q='L:'
,~-:r:R~E:I:,' ,
"
,- '-""'---". -,i.r'" ~--_.- -
; ! ,8:1': :.;
:::: I ~ ~
J::
"0"'-'-"--'"
" ,
.' .:",. .
:J.
~.'
\,
" .'
- . ....
-,7j - -
Br\YOI: -.
('11[('(;
1,'
If ,1
!.\-:l; D \)
I) I<:\J:-' \( '01.:\ '1-),\ Y
.('~
1';"":H..t;IHA:'~ '01011,
~~" ~
---
,rrRC":N~-r r.rVff'!.,'c..'; r""NT"RY
;';1--01-:.'::"'1-1 k.A.'~
.':,'.r,\.\'IN.\~~,,' ,"\"I-I-IW,f' ." I~.
. no . ,101: ,1'.1'. .J.. :1:1 ;. III, ;"1
>/1 'I'.' ,:':;.l..l
~
,..~
-I-
EPA
l"'nlHII' UI.\ II', I,(J'I,":
CO" 1'.\..\11'.\'1'10" ,\130n:
IU::-'IFDI.\I, (;O,,\I.S
,\ \H'I{I(' \' <. 'IH U~()I, ,,\ ()I{k:S, 1;\"
l'f'S\I'()I..\, 1'1 ORID,"
FHa Ht'. J
"
-------
! j
i i
:L/'" .1
...' ",""ioo~ I
,..- .,,~ :"'-' ";'-''''.~ -~
, i J
iL___-
....' 'J0CtJ : i
.. , ,
.u; :
. ;-- ...-.." -.. ~
i~~:<.~'-":""'" : I : ii
-17...'" ': :. 1
...:.-=/::/ ~...~._._-----_.~ . .. - _„.~.;'5.J Ln-~~
...J :..~t!}.:::: . l: i ..--!!IBEN7m"IJRAN . 11' [
",":.,-.., ! ......' ~"'"",",~ .f"''''''''''''' .
"':< .' . ...:.':::::: -.-.~..'-' ."~'~:.~~' "", . t;IMHLE :':>'TRE:ET .:
.' .::<......., (.. ~i,r/ """",/"\," ~'<~:-,.,.~"" - -~-- .-.~ [
:/,1'1 .." .: :
~iir ]80. . [: . ; :
'J! . I.;ii ,! , :
.- - '--~i'W':-'-:-'-"--'-I: ,1] :30.0- ....--.----t-::-:. -".'-..--------..-.-. .
. g Mv.;J.~ J.' _.- .- : .-.. "'. .. PINE H'. :-STREET-l
I !! :
\IWo-a .i ; : ,
. \,. :;YPRESS! ! :>rREE7 :
':'~'~~400'r; ~'. ~:[_. .~)~f6'. '. :; ..: 'H:'_::~-~ !---\s
r)()() t1 . ......-:~~'" ~., . . . ::
5~:,~- - -~~'i;11.~:-:~C~" '-_C~~-.'..I:::~~
. ~ ,
I.
'. ._-
I:
:) (J (\ (I rc::
FP.\
r;J
H()() 0
~
:~()80 ~
- - -
'.
I" .
- .
/1:\YO(;- ---
Ci {I( '(:
..
I.LC!:I\!>
L' .-1
[1".
L'~~I' .<~:.L
p r: \. .'::':.~ C' () LA rl.~ y
t1':N'i
\!'I'k:'\lv,,:1- "t-'.I!-!\I\.:"'. ti"l ".P\h',
.. II~III! '":'Htq~,,,r.
. r.N".'-"'''',,,', ",": 1-,\1 I-~PI'.f; Wt-"t-:Ui.\1. r;~'.'\I."
.... I~:
.',..., I ',1 . I,' nol. ~=" ~:t'!. :",
~,,~'T 'I U ,'.,:',-'1 r:
XEPA
I) F r:l' 1,0"\1 F
("0:" L\:\1L'-'.\TlO," ,\110\ l~
RI:...\li':DL\L (;O.\l.S
\ \' : :!~;..
',.'" ~'I.:!,('."'~I'; I: "'\~'I~!..;'" 1-~"
i ',.' \\ . ': ,.\ i I
FI(;\ . IoU: ~
l_~
-------
(HI) of.1. Chemicals contributing risk to these pathways were not
included if their individual carcinogenic risk contribution was
less than 1x10-6 or their noncarcinogenic Hazard Quotient (HQ) was
less than 0.1. In addition, chemicals were included if they
exceeded either State or Federal ARARs. A list of contaminants of
concern for groundwater and their associated exposure point
concentrations is shown in Table 1. The exposure point
concentration for each contaminant was derived using the 95 percent
upper confidence limit (UCL) on the arithmetic mean as defined by
the following formula:
95% UCL = X + an x 1.96
where:
X
an
=
arithmetic mean of the data
standard deviation of the data
=
If the 95% UCL resulted in a concentration higher than the maximum
concentration detected, the maximum concentration detected was used
as the exposure point concentration. In order to provide an
accurate assessment of risk from the site, EPA calculated exposure
point concentrations using sampling results from the Phase II Post-
RI, which provided the most current and complete set of groundwater
data avaiiable.
The site is currently abandoned. However, it was assumed for the
purposes of the BRA that future development could result in the
site itself becoming residential, since it is currently surrounded
on the south and east by residential properties. The groundwater
is not currently used for drinking water since the area is serviced
by the City of Pensacola potable water supply system. However, EPA
assumed in the BRA that the groundwater could be used for drinking
water and other potable uses in the future in the event existing
institutional controls designed to prevent or limit groundwater use
were not enforced. Additionally, private wells which have been
documented to exist in the area are currently used for irrigation
purposes.
6.1.2
Exposure Assessment
In the exposure assessment, EPA considered ways in which people
could come into contact with contaminated groundwater under both
current and future conditions. EPA determined that there is no
exposure to contaminated groundwater under current conditions.
However, under potential future scenarios, both existing off-site
residents and hypothetical on-site residents could be exposed if
groundwater were used as a potable water sourceJ It was assumed
that people could potentially drink and bathe with this water,
resulting in exposure through the ingestion, dermal contact, and
inhalation pathways. In addition to evaluating future adult
resident exposure, EPA considered potential exposure for a child
resident, since children generally represent a more sensitive
populallon. Final lifetlme risk estlmates were then calculated by
summlng the risks derived from both adult and child exposures.
, ~
.L~
-------
Table 1
Contaminant8 of Concern and
Bxpo8ure Point Concentration.
Contaminant of Concern Bxpo8ure Point
, Concentration (ma/l)&
Future Off- Future OD-
8it. 8it.'
Re8ident8 Re8ident8
Carcinogenic PAHs (total) 81 330
Benzo(b and/or k)Fluoranthene 24 96
~enzo(a)Anthracene 30 120
Chrysene ' , 27 110
,Naphthalene 580 ' 1,400
Acenaphthene 320 760
Dibenzofuran 240 560
Fluorene - 300 710
Phenanthrene 830 2,000
, , .. ' 150
Anthracene 37
Fluoranthene 270 1,100
Pyrene 170 690
Bis(2-ethylhexyl)Phthalate 0.02b .015
2-Methylphenol 4.3 7. 7b
(3-and/or 4-)Methylphenol 20 38b ,
Phenol 6.4 25
2,4-Dimethylphenol 7.3 lIb
Pentachlorophenol 1.9 3.9b
1,2,4-Trichlorobenzene 1.0 --
Carbazole 0.9 1.Ob
'Quinoline i 7.6 20b
Benzene 0.09 .10b
Cis-1,2-Dichloroethene i 0.87 --
I
Methyl Ethyl Ket'one 0.10 .14b
Styrene I 0.03 .04b
15
-------
- ~
I
Contaminant of Concern Exposure Point
Concentration (mg/l)a
Future Off- Future On-
site site
Residents Residents
Trans-l,2-Dichloroethene 0.34 --
Vinyl Chloride 0.26 --
a
Results rounded to two significant figures
Maximum concentration detected was used as exposure point
concentration
Compound was not detected in on-site groundwater
b
16
-------
The exposure assumptions for each pathway are provided in Table 2.
The same exposure assumptions were used for both off-site and on-
site adult residents. Similarly, the same assumptions were used
for both off-site and on-site child residents. Based on the
exposure point concentrations derived from site data for the
compounds shown in Table 1 and using the exposure assumptions
identified in Table 2, EPA estimated the average 'daily intake'(DI)
associated with each exposure pathway and population combination.
The formulas used to calculate the DI for each pathway are provided
in Table 3.
, 6.1.3
Toxicity Assessment
The toxicity assessment evaluated possible harmful effects of
exposure to each contaminant of concern. A number of compounds
found' at ,the site, "including benzene, PAHs, pentachlorophenol
(PCP) , and dioxins, have the potential, to caus,e cancer
(carcinogenic). Slope factors (SFs) have been developed by EPA's
Carcinogenic Assessment Group for estimating lifetime cancer risks
associated with exposure to pptentially carcinogenic compounds. '
These SFs, which are expressed in units of (mg/kg-day)-l, are
mUltiplied by the estimated intake of a potential carcinogen to
provide an upper-bound estimate of the excess lifetime cancer risk
associated with exposure 'at that intake level. The term "upper
bound" reflects the conservative estimate of the risks calculated
from ,the SF. Use of this approach makes underestimation of the
ac,tual cancer risk highly un).ikely. ' Slope factors are derived, from
results of human epidemiological studies or, chronic animal
bioassays to which animal-to-human extrapolation and uncertainty
factors have' been applied. , The SFs for the carcinogenic
. contaminants of ,concern are contained in Table 4.
Other contaminants of concern, such as dibenzofuran, may cause
other problems not related to cancer. Reference doses (RfDs) have
been developed by EPA for indicating the potential for adverse
health effects from exposure to contaminants of concern exhibiting
noncarcinogenic effects. RfDs i which are expressed in units of
mg/kg-day, are estimates of lifetime daily exposure levels for
humans, including sensitive individuals.' 'Estimated intakes of
contaminants of concern from contaminated groundwater can be
compared to the RfD. RfDs are derived from human epidemiological
studies or animal studies to which uncertainty factors have been
applied (to account for the use of animal data to predict effects
on humans). The RfDs for the noncarcinogenic contaminants of
concern are also provided in Table 4.
As an interim procedure until more definitive Agency guidance is
established, Region IV has adopted a toxicity equivalency factor
(TEF) methodology for evaluating chlorinated dioxins and furans.
This methodology relates the relative ,potency of each dioxin or
furan congener to the potency of 2.3.7,8-tetrachlorodibenzodioxin
(2,3,7,8-TCDD), the most toxic dioxin compound. The TEFs for the
dioxins/furans are presented In Appendix A.
- "7
1./
-------
Table 2
Exposure Assumptions for
Future On-site and Off-site Residents
Exposed to Contaminated Groundwater
Parameter
Adult Residents
Assumed Value
Child Residents
Standard AssumDtions
Exposure Frequency (EF)
Exposure Duration (ED)
350 days/~
chronic: 12 years
lifetime: 24 years
350 days/yr-
chronic: 6 years
Body Weight (BW)
A veraging Time (AT)
70 kg
chronic: 4,380 days
lifetime: 25,550 days
16 kg
chronic: 2,190 days
lifetime: 25,550 days
Ingestion Pathway
Ingestion Rate (IR)
2.0 L/day
1.4 L/day
Dennal Contact Pathway
Skin Surface Area (SA)
18,150 cm2
0.2 hr/day
lL/l000 cm3
7,195 cm2
0.2 hr/day
lL/l000 cm3
Exposure Time (ET)
Conversion Factor for Water (CF)
Inhalation Pathway
Inhalation Rate (IR)
0.6 m3fhr
0.2 hr/day
0.6 m3fhr
0.2 hr/day
Exposure Time (ET)
.
Assumes people are not home during 2 weeks of vacation per year
18
-------
In!estion Pathway
where:
Dl
CS
lR
EF
ED
'BW
AT
=
=
=
=
=
=
=
Dermal Contact 'PathwaY
where: Dl, =
CS, =
SA =
PC =
ET =
EF =
ED =
CF =
BW =
'AT =
Inhalation Pathway
where:
Dl =
CS ,-
lR =
ET =
EF =
ED =
BW =
AT =
...-.
Table 3
Daily Intake (DI) Formulas
DI= CSxIRxEFxED
BWxAT
average daily intake (mg/kglday)
exposure point concentration (mg/L)
ingestion rate (Uday)
exposure frequency (dayslyr) ,
exposure duration (years)
body weight (kg) ,
averaging time (days)
DI= CSxSAxPCxETxEFxEDxCF
BWxAT
average , daily absorbed dose (mg/kglday)
exposure point concentration (mg/L) ,
skin surface area available for contact (cm2)
permeability constant (cm/hr)
exposure time (hours/day)
exposure frequency (days/yr)
exposure duration (years)
volumetric conversion factor for water 01..11000 cm3)
body weight (kg)
averaging time (days)
DI= CSxIRxETxEFxED
BWxAT
average daily intake (mg/kg/day)
exposure point concentration (mg/L)
inhalation rate (m3fhour)
exposure time (hours/day)
exposure frequency (days/yr)
exposure duration (years)
body weight (kg)
averaging time (days)
19
-------
Table 4
Toxicity Values for
Contaminants of Concern
WelJ:ht of ORAL INHALATION
Evidence for Contaminant of Concern
Cancer Cancer SF C/u'onle RID' R efeftftce Caneer SF Chronle RID Refeftftce
NaplllhaJene . 4.0E-03 HEAST
f-----
Acenaphthene 6.0E-02 IRIS
f----
I> Dibenzofuran I.OE-02 HEAST
~---
D Auorene 4.0E-02 IRIS
Phenanthrene
..
D Anthracene 3.0E-OI IRIS
--'-'- - - .------
D Auoranthene 4.0E-02 IRIS
-_..-- -
D Pyrene 3.0E-02 IRIS
---.. ~--....._-_.
B2 Benzo(a)pyn:ne' 7.3E+OO IRIS
-...-.---- -..
B2 Benzo(b alld/or k)fluoranthene 7.3E+OO .
B2 Benzo(a)anlhracene 7.3E+OO . 6.IE+OO HEAST
-.
82 Ollysene 7.3E+OO .
B2 B i s(2 -eth ylhex y I )phthalate 1.4E-02 2.0E-02 IRIS
..--
2-Methylphenol S.OE-02 IRIS
----
(3 -and/or 4- )Methylphenol S.OE-02 IRIS
--
[) Phenol 6.0E-Ol IRIS
_. ..
2,4- Dimethylphenol 2.0E-02 IRIS
--.
B2 Pentachl oropheUoI l.2E"()1 3.OE-02 IRIS
~.
1,2.4- Trichlorobenzene 1.3E-03 HEAST 9.0E-03 HEAST
B2 Carbazole 2.0E-02 HEAST
20
-------
Table 4
(continued)
Weight of ORA" INHALATION
- Evidence for Contaminant at Concern
Cancer C8IIcer SF Chronic RID Reference . Cancer SF Chronic RID Reference
C Quinoline 1.2E+01 HEAST
~_._._-_.
A Benzene 2.9E.{)Z IRIS 2.9E..()Z HEAST
~_.
Cis-Z.3-Dichloroethene I.OE..()Z IRIS .
~----
D Methyl Ethyl Ketone S.OE"()Z IRIS 1.0E+00 IRIS
1--..
U2 Styrene 3.0E-OZ 2.0E-01 IRIS' I.OE+OO IRIS
---.-
Tran;-1.2:Dichloroelhene 2.0E"()2 IRIS
1---_.
A Vinyl {'l1loride 1.9E+00 HEAST '3.0E"()1 HEAST
. _U'-"'--- ,-. .--- --.
B 2.3,7,8- TCDO (equivalents) I.SE+OS IRIS I.SE+OS IRIS
IRIS
HEAST
. Integrated Risk Informa.tion System
. Health Effects Assessment Summary Tables
Although Benzo(a)pyrene (BaP) was not detected in groundwater, EPA customarily relates the potency of other
carcinogenic PAHs to the toxicity of BaP. For the ACW site, it was assumed that each carcinogenic PAH was
as potent as BaP.
*
Since no slope factor exists for this compound, the slope factor for SaP was used. This is a conservative
assumption, since the other PAHs are considered less toxic than BaP.
. 21
-------
6.1.4
Risk Characterization
The centerpiece of the BRA is the risk characterization, which
combines the other components of the evaluation to estimate the
overall risk from exposure to site contamination. For cancer-
causing compounds, risk is a probability that is expressed in .
scientific notation. For example, an excess lifetime cance~ risk
of 1x10-6 means that an individual has an additional 1 in 1,000,000
chance of developing cancer as a result of site-related exposure
over an estimated 70 year lifetime. EPA has established a target
risk range for Superfund cleanups of between 1x10-4 (1 in 10,000)
and 1x10-6. The formula used for calculating cancer risks is shown
below:
R~sk = DI x SF
DI
=
a unitless probability of an individual
developing cancer
chronic daily intake averaged over 70 years
(mg/kg-day)
slope-factor, expressed as (mg/kg-day)-l.
where:
risk =
SF
=
Estimated cancer risks associated with potential future potable use
of groundwater at the ACW site are extremely high, approaching 1.0
for the ingestion and dermal contact exposure pathways for both on-
site and off-site residents. These "upper bound" probability
estimates predict that an individual exposed to the concentrations
and exposure rates assumed in the BRA will contract cancer. These
risks are primarily associated with PAHs in the groundwater.
Inhalation risks for both on-site and off-site residents were
associated with VOC contamination. A summary of the cancer risks
for each contaminant of concern is presented in Table 5. Total
cancer risks for each population group evaluated are provided in
Table 6.
For 'compounds which cause. toxic effects other than cancer, EPA
compared the average concentration of a contaminant found at the
site with a reference dose representing the maximum amount of a
chemical a person could be exposed to without experiencing harmful
effects. The ratio of the average daily intake to the reference
dose is called a hazard quotient (HQ). The formula for calculating
the HQ ~s shown below:
Noncancer HQ = Dr/RfD
where:
Dr
RfD
=
chronic dally lntake
reference dose
=
Dr and RfD are expressed In the
represent the same'exposure period
short-term) .
same
(i. e. ,
units (mg/kg-day) and
chronic, subchronlc, or
;'J
~"-
-------
Table 5
Individual Risks Associated with
Contaminants of .Concern.
Hazard Quotients Cancer Risks
-
Contaminants at Concern On.slte Groundwater OIf.sIte Groundwater On.slte Groundwater OIf.slte Groundwater
-
Ingest. Dermal Inha!. Ingest. Dermal Inhal. Ingest. I>mnal Inha!. 'ngest. Dermal 'nlla!.
(Child) (Child) (Child) (Child) (Child) (Child) (Adult) (Adult) (Chl~) (Adult) (Adult) (Child)
.'/aphlhaJe.ne 30,000 4,000 _. 10,000 2,000 -. -- " -- .. .. ..
f----
Acenaphlhene 1,000 300 .. 400 100 .. .- .. eo .. -- ..
Dibcnzofuran 5,000 1,000 .. 2,000 600 .. .. -- . -. eo .. ..
----
Huorene 1,000 500 -- 600 200 eo .. -- .- .. .. ..
1---------..---- --
l'henanlh.cne u -. .. eo .. .- .. " .. -. eo ...
---.-..--... -- --.~
Anthracene 40 20 .. 10 5 -- .- " .. .. .. --
.--'--'-------"--- -.--...
I-luoranlhene 2,000 2.000 .. 600 400 .. -- " .. .. .. --
--.-.-,..--. - -
Pyn:llt 2,000 1.000 500 300 . . ..
... .. .. .. .. .. ..
. -----.-..,-. .-.--.-....-... - -
Henzotb and/or k)fluoranthene' -- -- ... .. .. -- I.OE+OO I.OE+OO .. I.OE+OO I.OE+OO -.
Henzota)anlhracene .. .- -- -. -. .. I.OE+OO I.OE+OO eo I.OE+OO I.OE+OO --
lluysene -- .. -- -- -- .. I.OE+OO 1.0E+00 .. 1.0E+00 1.0E+00, ..
-- -
Bist2~lhylhexyl)phtha1ate 0.06 0.003 '-. 0.08 0.004 eo 2.0E-%' I. 7E.{)7 .. 2.6E-% 2.3E.{)7 .-
--
2. Melhylphenol 10 0.04 eo 7 0.02 .. -. " -. - -- --
-.
(3.and/or 4- )Methylphenol 60 0.4 ., 30 0.2 .- .- " .. .. - ..
Phenol 4 0.04 eo 0.9 0.01 .. .. " .. .. - ..
--
2,4- Dimethylphenol 50 1 .. 30 0.9 .. " " - .. -
Pentachlorophenol 10 10 .- 5 7 .. 4.4E-03 I.OE-02 - .2.1Ł-03 5.0E-03 ..
1,2.4' T richlorobenzcne 0 0 0 60 10 .10 .. .. eo - .. -
23
-------
Table 5
(continued)
Huard Quotients Cancer RlskJ
Contaminants of Concern On.slte Groundwater Off.slte Groundwater On.slte Groundwater Off.slte GroundwatN
,
Ingest. Dmnal Inhal. Ingest. Dflmal Inhal. Ingest. Dflmal Inhal. Ingest. Dermal Inhal.
(Child) (Child) (Child) (Child) (Child) (Child) (Adult) (Adult) (Child) (Adult) (Adult) (Child)
Camazole .. u ., .. .. .. 1.9E4t 1.0E-06 .. 1.7E4t 9.2E~ ..
--'-----
Quinoline -- .- ., .- -. .. 9.0E-01 J.2E-02 .. S.8E-01 4.7E-03 ..
--
Benzene .. -- .. -- .. .. 2. 7E-OS 2.1E-06 2.9E-OS 2.SE-OS 1.9E-06 2.6E-OS
-
Cu. 2,3. Dichloroethene 0 0 .. 7 0.1 .- .. h O.OE+oo .. u 7.0E4t
--
MetlJyl Ethyl Ketone 0.2 O.OOOS 0.02 0.2 0.0004 0.02 .. -- -- .. .. ..
w.....--..-- - ------- -
Styrene 0.02 0.002 0.005 0.01 0.001 0.004 1.1 E-05 2.2E-06 .- 8.SE-06 J.7E-06 -.
.....------ ~.---_._'''''~----_.
T nlM I J Dlchloroelhene 0 0 " I 0.03 .. .. .. .. .. .. .'
-----'--' .-
Vinyl Chloride .. u .. .. -. .. O.OE+oo O.OE+oo O.OE+oo 4.6E-03 1.2E4t 7.8E4t
[ {otal Pllthway 41,000 8,800 0.03 14,000 3,600 10 1.0E+00 J.OE+oo 2.9E-OS 1.0E+00 J.OE+oo J.SE..{)3
The risk for the more sensitive .population (adult or child) is shown.
No RID or Slope Factor is available for the compound under this pathway.
24
-------
Table 6
Summary of Future Cancer ai8k8
As80ciated with Groundwater Contamination
bces8 Lifetime Cancer Risk
Groundwater
Exposure Pathway Adul t Child Adult Child
on-8ite on-8ite. Off-site Off-site
Re8ident Re8ident Resident Resident
Ingest:lon 1.0E+00 1.0E+00 1. OE+O 0 1.0E+00
Dermal Contact 1.0E+00 1.0E+00 1.0E+00 1.0E+00
Inhalation 2.7E-OS 2 ~9E-:OS 1.4E-03 1.SE-03
.Total . Cancer Risk1 1.0E+00 1.0E+0'0 1.0E+00 1.0E+00.
1
.".
Cancer risks cannot theo'retically exceed 1.0, since
risk is presented as a probability. A risk level
. of 1.0 predicts that an individual exposed to the
concentrations and exposure rates assumed in the
BRA will contract cancer.
Table 7
Summary of Future Hazard Quotients
Hazard Quotient
Groundwater
Exposur~ Pathway Adult Child Adult . . Child
on-site on-site Off-site Off-site
Res ident' Resident Resident Resident
Ingestion 13,000 41,000 5,300 14,000
Dermal Contact 5,100 8,800 2,000 3,600
Inhalation .006 i .03 3 10
j
Total Hazard Index1 20,000 50,,000 7,000 20,000
. 1
Tbe hazard, index was rounded to one significant
figure.
25
-------
The hazard index (HI) can be generated by adding the HQs for all
contaminants of concern that affect the same target organ (such as
the liver) within a medium or across all media to which a given
population may reasonably be exposed. In general, EPA considers an
HI of 1.0 to be the maximum acceptable hazard. However, the ACW
risk assessment estimated an HI of 50,000 for a future child on-
site resident. For both on-site and off-site residents, non-cancer
risks for ingestion of and dermal contact with site groundwater
were primarily associated with PARs. Non-cancer risks for the
inhalation pathway stemmed from VOC contamination in the
groundwater. A summary of the potential future HQs for each
contaminant of concern is presented in Table 5. Hazard indices
(HIs) for each population group are in Table 7.
It should be stressed that current human health risks associated
with direct exposure to contaminated groundwater are minimal since
residents near the site are connected to the City of Pensacola
potable water supply. Therefore, no one is currently using the
groundwater near the ACW site for drinking or bathing. However, as
indicated in Section 6.1.1, EPA has evidence to suggest that some
private wells located in the vicinity of the site are being used
for residential irrigation purposes. Based on samples collected
from two of these wells in June 1988, EPA plugged an irrigation
well on the condominium property south of the site in 1991. A
survey of residents near the site will be necessary to locate as
many additional wells as possible.
In summary, the results of the BRA indicate that human health risks
associated with potential future scenarios at the ACW site excee~
EPA's target risk range for protection of human health. Therefore,
actual or threatened releases of hazardous substances in the
groundwater in the area of the ACW site, if not addressed by EPA.'s
preferred alternative or one of the other alternatives considered,
may present a current or potential threat to public health and the
environment.
6.1.5
uncertainties in the Risk Assessment
The factors that contribute un~ertainty to the estimates of
exposure concentrations, daily intakes, and toxicity information
also contribute uncertaint.y to the estimates of risk. These
factors include:
. Chemicals not included in the risk assessment
. Exposure pathw~ys not considered
. Derivation of exposure point. concentratio~s
. Int.ake uncert.alnty
. Toxicological dose-response and toxicity values
If a compound does not. have an asslgned slope fact.or and it had
dat.a qualifiers indicating t.he presumptive evidence of its
presence. It was eliminated from t.he quantitative risk assessment.
Compounds identlfled uSlng presumptlve eVldence cannot be given the
26
-------
same weight as a compound which was positively identified. If a
compound had data qualifiers indicating that the data were not
useable, it was also eliminated from the risk assessment. Also,
compounds that do not have an assigned reference dose or slope
factor were eliminated from the risk assessment. Elimination of
these compounds will result in an underestimation of risk.
There are uncertainties associated with summing cancer risks or
hazard indices for different chemicals.. The cumulative dose
ignores possible synergism or antagonism among. chemicals and
differences in mechanisms of action and metabolism. However, for
the ACW site, the risks for most of the individual contaminants of
concern fell outside the acceptable risk range p.rior to being
summed.
Another uncertainty surrounds the fact that risk calculations for
.dermal exposure. to . all comPounds are evaluated using. dermal
toxicity values. The dermal toxicity values represent an
adJustment to the oral toxicity value to reflect an absorbed dose
rather. than an administered dose. The accuracy of this adjustment
depends on the suitability of the absorption rate which was used to
make the adjustment. This and other uncertainties need to be
considered when evaluating the results of the risk assess~ent.and
when making risk management decisions for the site.
6.2 Environmental Risks.
To ev~iuate the potential ecological impacts from the site, EPA
initiated a phased approach to ecological studies. The initial
phase of the ecological assessment, known as the Dye Dispersion and
Sediment Sampling Study, was completed by EPA in 1991. The
objective of this study was to determine the presence and
concentration of site-related contaminants within the area of
Pensacola Bay influenced by .surface water drainage from the PYC
drainage ditch. This ditch has historically received surface
runoff from the ..ACW site, and contaminated groundwater may also be
discharging into the ditch. . . .
Significant conclusions from the study are presented below:
o
Continuous communication between the PYC ditch and the bay was
afforded by the presence of an lS-inch'concrete culvert even
when the mouth of the dicch was occluded by a sandbar.
The presence of a 15 ft. deep navigation channel entering
.Bayou Chico suggests. a po.tential additional sourcEi! for
contamination in the nearshore bay area.
o
o
No organic compounds were detected within the upper stratum of
the bay sediments.
o
Toxic levels of organic compounds, princiDally anthracene,
fluoranthene, and pyrene, were detected within the drainage
27
-------
ditch and lower stratum of the bay sediments at the mouth of
the ditch.
o
Levels of organics and metals in the surface waters were
within normal ranges found throughout southeastern estuarine
systems.
Following evaluation of the results of this investigation, EPA,
FDEP, and the Natural Resource Trustees will determine whether a
subsequent study is necessary~ This second study would involve the
collection of water and sediment samples for toxicity tests,
testing of biota for contaminant levels, and bioaccurnulation
studies.
7.0
DESCRZPTZON OF ALTERNATZVBS
EPA conducted an FS to identify and evaluate appropriate remedial
alternatives for minimizing current and future risks to people and
the environment posed by contaminated groundwater. In the FS,
remedial al ternati ves were assembled from applicable remedial
activities known as process options. These alternatives were
initially evaluated for effectiveness, implementability, and cost.
In order to fully address this contamination, EPA considered four
alternative? for removing and treating the separate DNAPL layer and
five alternatives for treating dissolved groundwater contamination.
Included among the remedial alternatives is the no action
alternative, which is required by the NCP to serve as a basis for
comparison to the other alternatives.
Alternatives considered for addressing DNAPL contamination at the
ACW site include the following:
Alternative DNl
Alternative DN2
No Action
DNAPL Extraction and On-site
Thermal Treatment
DNAPL Extraction and Off~site
Treatment
DNAPL Extraction and Recycling
Alternative DN3A
Alternative DN3B
The alternatives considered for addressing dissolved groundwater
contamination include the followlng:
Alternative GW4
No Action
Groundwater Use Restrictions and
Monitoring
Extractlon, Treatment, and Surface
Water Discharge
Extraction, Treatment, and
Reinjection
In-Situ/Ex-Situ Biorernediation
Alternative GWl
Alternative GW2
Alternative GW3A
Alternative GW3B
28
-------
7.1
Alternative DNl - No Action
Under the No Action alternative for DNAPLs, no remedial action
would be taken at the ACW site to' address the separate DNAPL layer
in the groundwater. No measures would be taken to reduce the
potential for exposure through the use of institutional Gontrols,
containment, treatment, or removal of DNAPLs. As required by the
NCP, the no action alternative provides a baseline for comparison
with the other alternatives which offer a greater level of
response.
EPA estimates that approximately 7.25 million gallons of DNAPL are
present in the aquifer beneath and immediately down-gradient of the
site.. Since Alternative DNl does nothing to remove or contain any'
of .this material, the risks posed by the site would likely increase
as ..the DNAPL migrates both horizontally and vertically,
'contaminating currently uncontaminated portions of the aquifer and
potentially impacting surface water. There are no costs associated
with implementation of Alternative DN1.
7.2 . Alternative DN2 - DNAPL 2xt~action; on-site Thermal Treatment
Alternative DN2 involves extraction of a combination of groundwater.
and DNAPL cQntamination, separation of the' aqueous and non-aqueous
phases, treatment. and reinj ection of groundwater, and on-site
. incineration of recovered DNAPL. . . . . .
Enhanced removal technologies would be' used to increase the DNAPL
removal efficiency. Enhanced removal can include the use of one or
more Qf the following process options: water flooding, alkaline
water flooding, surfactant water flooding, and polymer water
flooding. Water flooding utilizes the inj ection of water into
wells to hydraulically sweep DNAPL toward production or recovery
wells. Alkaline water flooding relies on the addition of alkaline
agents into the wa.ter flo.od which .raise the pH of the water and
react with organic acids in the DNAPL to generate surfactants at
the oil-water interface. This reaction leads to improved recovery
due to reduced interfacial tension, emulsification effects, and
wett.ability reversals. Surfactant water flooding involves the
injection of a surfactant solution as a slug in a flooding sequence
to decrease the interfacial tension between DNAPL and water by
several orders of magnitude. This has the effect of improving the
displacement efficiency of the flood, increasing DNAPL recovery,
and reducing residual DNAPL saturation. Polymer water flooding
uses. polymers in the flood to reduce the mobility ratio (mobility
of the 'displacing fluid divided by the mobility of the displaced
fluid) . The result is improved sweep efficiency. A typical
flooding sequence might consist of water, alkaline, surfactant, and
polymer flooding conducted in serles, followed by water flooding to
displace the viscous polymer and DNAPL combination.
Al~ernative DN2 conceptually involves the use of two extraction
wells pumping at a combined rate of'up to 100 gpm. The enhancing
29
-------
agents are introduced into the aquifer via two injection wells
located just upgradient of the DNAPL zone. Employing a flooding
sequence similar to the one described above, it is expected that a
maximum of 30 percent of the DNAPL can be extracted in 50 pore
volumes. This means that based on an estimated 7.25 million
gallons of DNAPL present in the subsurface, only 2 million gallons
are recoverable using enhanced recovery methods. It would take
approximately 30 years to remove 50 pore volumes. Further
characterization of the extent of DNAPL contamination, aquifer
pumping t~sts, and detailed computer mOdelling will be necessary
during design to determine well locations, depths, and pumping
rates.
Following extraction, water and DNAPL would be separated using
centrifugation or another appropriate separation technology. The
DNAPL would be thermally destroyed on-site in accordance with RCRA
requirements in 40 CFR 264.601 and 265.400, and the recovered water
would be treated to meet Federal and State primary drinking water
maximum. contaminant levels (MCLs) using the selected groundwater
treatment alternative.
The estimated capital cost for this alternative is $3,441~OOO, with
an annual operation and maintenance (O&M) cost of $546.000. This
results in a net present worth cost of $11,825,000 for Alternative
DN2.
7.3
Alternative DN3A - DNAPL Bxtraction; Off-site Treatment
This alternative is similar to Alternative DN2, except the
recovered DNAPL would be transported off-site to an approved RCRA
facili ty for treatment. Currently, the only off -site treatment
technology widely available lS lncineration, so cost estimates are
based on this technology. RCRA requirements under 40 CFR 263 and
264 would apply to the transportation of the DNAPLs, and the off-
slte treatment facllity would have to meet requirements in 40 CFR
264.601 and 265.400 and the Superfund Off-slte Policy (OSWER
Directive 9834.11).
The estimated capital cost for this alternative is $2,506,000, with
an annual O&M cost of $867,000. This results in a net present
worth cost of $15,832,000 for Alternative DN3A.
7.4
Alternative DN3B - DNAPL Extraction; Recycling
This alternative is similar to Alternative DN3A, except the
recovered DNAPL would be transported to a recycler for r~use as
product. The significant volume of DNAPL which lS expected to be
recovered at the ACW slte makes recycling a viable alternative.
~hlS alternative would utillze a temporary unit (TV) as defined by
HCR.;; Subtitle C for the storage of DNAPLs at the site until
sufflcient quantlties accumula~e for off-site transport and
recyling. The alterr:atlve would comply with all substantive
20
-------
portions of the corrective action management unit (CAMU) rule
percaining. co TUs. This TU would therefore not be subject to the
requirements of the RCRA Land Disposal Restrictions or Minimum
Techno~ogy Requirements. Off-site recycling activities would
comply with the provisions of the Superfund Off-site Policy".
. .
. .
The estimated capital cost for this alternative is $2,586,000, with
an annual O&M cost of $351,000. This results in a net present
worth cost of $7,978,000 for Alternative DN3B.
All alternatives for the extraction of DNAPL are expected to leave
.behind a significant amount of residual DNAPL in the saturated zone
(an estimated 70%)" . The residual DNAPL will be a source of
groundwater contamination by dissolution over time. In 'order to
control the migration of contaminated groundwater, a containment
system consisting of extraction and/or injection wells may also be
necessary.
!t?;~'5,."~"AlternatiYeGWl - No Action
Under the No Action alternative for groundwater, no remedial act.ion
would be taken at the ACW site to 'address dissolved contamination
in the groundwater . No measures would be taken to reduce the
potential for exposure through the use of. institutional controls,
containment -, t.reatment, or. removal o.fcontarninated . water. As
required by the NCP, ,the no action alternative provides a baseline"
for comparison with the other alternatives which offer a greater'
level of response. .
EPA estimates that approximately 152 million gallons of groundwater
are contaminated above the site-specific alternate concentration
limits (ACLs) established under CERCLA Section 121 (d) (2) (B) (ii) for
the site. These ACLs', shown in Table 8, were developed to ensure.
compliance with surface water standards at the point where
groundwater discharges to surface water. Since area re~ddents and.
businesses are on the city water'supply, and the groundwater in the
vi~inity of the site is presently proposed as a delineated area
under Chapter 17-524.420, F.A.C. to restrict the potable use of the
aquifer, EPA believes that adequate institutional controls exist to
support the use of ACLs. Therefore, ACLs are more appropriate than
primary drinking water standards (MCLs) or risk-based levels as
remedial goals for groundwater.
Since Alternative GW1 does nothing to remove or contain any of this
contamination. the risk~ posed by the site would likely increase as
groundwater contaminants migrate both horizontally and vertically,
degrad{ng currently uncontaminated portions of the aquifer and
potentially impacting surface water. There are no costs associated
with implementation of Alternative GW1.
31
-------
TABLE 8
Groundwater Remedial Goals
Compound
Remedial Goal
(ug/l)
Volatile Ol"2anics
Benzene
91
Semi. Volatile Ol"2anics
Acenaphthene
Fluoranthene
Naphthalene
Total Carcinogenic P AHs
Benzo(a)Anthracene
Benzo(b&k)Fluoranthene
Benzo(a)Pyrene
- Chrysene
Anthracene-
Fluorene-
Phenanthrene-
Pyrene-
Dibenzofuran
Pentachlorophenol
9,000
1,500
21,900
1,100
44
296,000
"These compounds, while not currently considered to be carcinogenic, were
originally incorporated into the ACL calculation for carcinogenic PAHs.
32
-------
7.'6
Alternative GW2 - Groundwater Use Restrictions and Monitorina
Under this alternative, institutional controls would be
implemented, restricting the use of the groundwater from the
contaminated plume within the Sand-and-Gravel Aquifer. These
State-:imposed restric~ions include deed restrictions preventing
current and future use of the aquifer 'for such purposes as potable
and industrial water supplies, irrigation, washing, etc. Permit
restrictions would require the State of Florida to restrict all
well drilling permits issued for new wells on the properties which
may impact the contaminated groundwater plume. These restrictions
would be written into the property deeds to inform future property
owners of the possibility of contaminated groundwater beneath their
property. '
in addition to these restrictions, quarterly groundwater monitoring
of all existing monitor wells would be implemented. Analytical'
parameters to be evaluated would include at a minimum PAHs, PCP,
VOCs, phenols., and dioxin. Surface water monitoring would also be
conducted at the Pensacola Yacht Club drainage ditch to evaluate
the potential impacts of contaminated groundwater discharges on
surface water quality. For cost estimating purposes, it was
assumed that monitoring would continue for a minimum of 30 years.,
The primary ARARS ,which apply to this alternative are the ACLs
develope,d by EPA as remedial goals for groundwater. Since no
extraction or treatment of groundwater would take place under this
alternative, exceedances of these levels would continue to occur,
and the risks posed by contaminated groundwater would continue to
increase.
The estimated capital ,cost for this alternative is $197,000, with
an annual operation and maintenance (O&M) cost of $83,000. ' This
results in a net present worth cost of $1,474,000 for Alternative
GW2. '
7~7
Alternative GW3A. - Extraction and Treatment; Surface Water
Discharae
Under this alternative, three extraction wells would pump
contaminated groundwater at a combined rate of 105 gpm to an on-
site treatment facility. primary treatment steps are UV-oxidation,
activated sludge, and granular activated carbon (GAC) adsorption.
Auxiliary processes include dissolved air floatation
(pretreatment), sludge, dewatering. via a filter presf?,,' and
filtration prior to GAC adsorption. Treated groundwater would be '
discharged to Pensacola Bay. The goal of this alternative would be
to treat groundwater,to the remedial goals outlined in Table 8.
However, the ability to achieve these goals throughout the plume
cannot be determined until the extraction and treatment system has
been implemented and modified as necessary and the plume's response
has been monitored over time.
33
-------
In general, the extraction well layout is conceptual based on an
analytical groundwater model. It is assumed that the extraction
wells will be placed to the depth of the lower most zone of
contamination. Upon completion of aquifer testing to be conducted
during design, detailed groundwater flow modelling would be
performed to more precisely estimate locations and depths of wells
along with pumping rates that will be required to extract.
groundwater from the various zones within the aquifer. The assumed
duration of the extraction and treatment process is 30 years, which
will prov.ide for treatment of approximately 11 pore volumes of
contaminated groundwater from the plunLe.
Inclusion of a dissolved air flotation (DAF) system is required
since the selected DNAPL recovery system is expected to leave a
substantial amount of residual DNAPL contamination within the
aquifer. The DAF system includes a circular basin equipped with a
skimming arm to handle floating product, and a scraper arm and
sludge trap for sinking product. The DAF system will also benefit
the UV-oxidation system, which is color sensitive, by providing a
clearer influent. The DNAPL will be periodically collected and
treated using the selected DNAPL treatment al ternati ve.
Preliminary sizing indicates that a 20 foot diameter basin is
appropriate.
The UV-oxidation process involves use of ultraviolet light to
catalyze the chemical oxidation of organic contaminants in water by
its combined effect upon the organic contaminant and its reaction
with hydrogen peroxide. The UV-hydrogen peroxide reaction would
result in formation of hydroxyl radicals, second only to fluorine
in oxidative power, which then react with organic contaminants in
water. The UV-oxidation process is capable of quickly destroying
VOCs such as trichloroethane, vinyl chloride, tetrachloroethane,
l,l-dichloroethene, and others depending on oxidation time. The
system can also treat phenolic compounds and PARs, such as
naphthalene and acenaphthalene. UV radiation has been used to
generate mutated microorganisms capable of biodegrading complex
chlorinated organics. pilot testing would be necessary to
determine the applicability of UV-oxidation in treating dioxins and
PARs. The UV-oxidat1on unit selected would be a function of the
flow rate and the required oxidation time, both of which would be
determined through pilot testing.
The activated sludge treatment process would be based on a system
where aeration, clarification, and sludge recycling would be
provided in a single package unit. Several package plant designs
are available. Some systems consist of a single basin structure
with an outer tank used for aeration and an inner tank for
clarification. Other package designs feature separate basins that
are operated in series for aeration and clarification. Multi-media
tertiary filtration would be dewatered via a filter press with
filtrate recirculated to the activated sludge plant. Dewatered
sludges would be sampled to determlne If they exhiblt hazardous
characteristics. If the sludge ~s hazardous, it would be disposed
34
-------
in an off-site RCRA Subtitle C landfill. Otherwise, the sludge
could go to a RCRA Subtitle D sanitary landfill.
The GAC adsorption system would consist of two sets of' three down-
flow carbon beds each connected in series. For discussion and
illustration purposes, each bed would be approximately 5 feet in
diameter by 6 feet high. The GAC system 'is expected to provide'
polishing treatment to remove any organics not removed by {N-
oxidation or activated sludge treatment. Effluent from the GAC
system would be discharged to a clear well and monitored prior to
surface water discharge. ,.
The treatment system would be designed 'to treat groundwater to the
surface water discharge standards outlined in the National
Pollutant Discharge and Elimination System (NPDES) under the Clean
W,ater' Act. (40 CFR 122, 'Subpart C) ~ Since' the treated groundwater
would be discharged off-site, a permit'would be required.
The estimated capital cost for this alternative is 53,553,000, with
an annual O&M cost of $349,000. This results in a net present'
worth cost of $8,910,000 for Alternative GW3A.
7.8
Alternative GW3B - Extraction and Treatment; Reiniection
Alternative- GW3B is similar to Alternative GW3A, except that
, treated groundwater would be reinj ected into the aquifer' instead of
being discharged to surface water~ Reinjection would provide a
degree of ,containment of the contaminant plume and minimize salt
water intrusion associat'ed with operation of the extraction system.
The goal of this alternative would be to treat groundwater to the
remedial goals outlined in Table 8. However, the ability to
achieve these goals throughout the plume cannot be determined until
the extraction and treatment system has been implemented and
modified as necessary and the plume's response has been monitored
over time. .
Groundwater would be treated' to mee't Federal and State primary
drinking water maximum contaminant levels (MCLs) prior to being
reinjected into the aquifer. The estimated capital cost for this
alternative is $3,662,000, with an annual O&M cost of $349,000.
This results in a net present worth cost of $9,019,000 for
Alternative GW3B.
7.9
Alternative GW4 - In-Situ/Ex-Situ Bioremediation
Alterna'tive GW4 combines in-situ and above-ground biologica'l
treatment. The process would involve pumping contaminated
groundwater at a combined rate of 105 gpm to an on-site treatment
facllity, consisting of a DAF system, continuous flow bioreactor,
clarifier. media filter, and a GAC column. The treated effluent
would then f low to a holding tank where hydrogen peroxide and
nutrients would be added prlor to in]ectlon lnco the aquifer. The
inJection system was developed soiely to illustrace the general
35 '
-------
concept of oxidant/nutrient injection into the aquifer. It is
anticipated that the total bioremediation operation would require
5 years to achieve aquifer restoration consistent with the remedial
goals shown in Table 8. This scenario will treat a total of
approximately 1.8 pore volumes of contaminated groundwater.
However, the ability to achieve these goals throughout the plume
cannot be determined until the extraction and treatment system has
been implemented and modified as necessary and the plume's response
has been monitored over time.
Use of the in-situ bioremediation techniques has potential
advantages compared to conventional .pump and treat. remedial
actions for contaminated groundwater plumes. Using pump and treat
techniques, a residual fractipn of organic contaminants will remain
adsorbed to organic and mineral components of the aquifer matrix
after efforts to remove concentrated forms of the contaminant, such
as creosote oils, have ceased to be productive. . This contaminant
fraction may be unrecoverable using standard pumping methods and
will continue to slowly solubilize into the groundwater system.
Remediation of the aquifer using a standard pump and treat scheme
typically requires several . flushes. of the aquifer system within
the affected area.' ,
Bioremediat,ion schemes attempt to either stimulate naturally
occurring aerobic microorganisms to degrade contaminants in situ,
or introduce microorganisms capable of' degrading the contaminants.
Indigenous microorganisms would be used if capable of degrading
site contaminants. Treatability testing would be used to determine
the need for specialized microbes. Typically, biodegradable
contaminants can be degraded at rates which are orders of magnitude
greater than the leaching rate of the contaminant in a soil/water
system, provided environmentally limited nutrients and oxygen are
added as growth enhancing agents. In particular, phenolics, PAR's
and ketones are all readily biodegradable by many indigenous
microorganisms.
The in-situ/ex-situ remediation process wOu.ld first involve pumping
of contaminated water from extraction wells through the DAF system
to remove any oil and free product prior to treatment in the
bioreactor, where the bulk of the contaminants would be removed.
Oll and free product would be addressed under one of the DNAPL
remedial alternatives. The effluent from the bloreactor would then
flow to a clarifier where suspended solids would be settled out to
avoid clogging problems in the injection wells. $ludge from the
clarifier would be dewatered via a filter press, with filtrate
recirculated to the bioreactor. Dewatered sludge would be
transported to an off-site landfill for disposal.
Effluent from the clarifier would then pass through a granular
activated carbon column to remove any remaining contaminants before
flowing to a holding tank where it would be amended with inorganic
nutrients and hydrogen peroxide. The nutrient-enriched water would
then be pumped to reinjection wells. Hydrogen peroxlde lS used as
36
-------
ap oxygen source because it readily breaks down into oxygen and
water. . This oxygen-' and nutrient-rich water would enter the
aquifer, providing the oxygen and nutrients necessary for in-situ
treatment.
This water also acts as a carrier for contaminants that .have been
released by the soi1s due to the natural surfactants produced by
the microbial activity. The contaminants would then be available
to in-situ degradation or they would be destroyed in the above-
ground bioreactor after extraction. This combination of in-situ
and above-ground treatment would expedite the overall aquifer
restoration. An estimated 20 gpm of treated groundwater would be
purged from the system and discharged to the Escambia County'
utilities Authority (ECUA) publicly owned treatment works (POTW).
Effluent monitoring would be performed prior to discharge to assure
compliance with the POTW discharge' limitations. In addition,
periodic monitori'ng of irifluent groundwater would be necessary to
assess the effectiveness of the treatment process~
Groundwater would be treated to meet Federal and State MCLs prior
to being reinjected into the aquifer. The estimated .capital cost
for this alternative is $3,906,000', with an annual O&M cost of
$452,000. . This results in a net present worth cost of '$5,865,000
for Alternative' GW4.
8~O
COKPARATJ:VB ANALYSJ:S OF GROONDWATBR AND DNAPL ALTBRNATJ:VBS
, .
In this section; the performance of each alternative relative to
the other alternatives will be evaluated for each of the nine
criteria identified ih the NCP (40 CFR Part 30'0.430). The criteria
are listed in the NCP and discussed further in EPA's guidance for
conducting Remedial Investigations and 'Feasibility Studies. The
nine criteria are segregated into three categories. Threshold
Criteria are those which dictate the minimum standards with which
a remedial alternative must comply. Primary Balancing Criteria
include those which are used to evaluate the effectiveness' of the'
remedial .alternati ves. Finally, Modifying Criteria are those' which
may be used in distinguishing between equally protective
alternatives. The nine criteria are shown below:
. ' .
Threshold Criteria
o
0,
Overall Protection of Human Health and the Environment
Compliance with ARARs
Primary. Balancing Criteria
o
o
o
o
o
Long-Term Effectiveness and Permanence
Reduction of Toxicity, Mobility, or Volume
Short-term Effectiveness
Implementability
Costs
through Treatment
3"7
-------
MOdifying Criteria
o
o
State Acceptance
Community Acceptance
A comparison of the remedial alternatives with respect to each of
these criteria and each other is presented in the following
sections. The discussion has been arranged to provide a comparison
among the DNAPL alternatives followed by a separate evaluation of
groundwater alternatives. Those alternatives which fail to meet
the threshold criteria of overall protection of human health and
the environment and compliance with ARARs will be eliminated from
further analysis.
8.1
Overall Protection of Human Health and the Environment
This criterion assesses whether alternatives adequately protect
human health and the environment and to what degree an alternative
would eliminate, reduce, or control the risks to human health and
the environment associated with the site through treatment,
engineering, or institutional controls. It is an overall
assessment of protection that encompasses other criteria such as
long-term effectiveness and permanence, short-term effectiveness,
and complia~ce with ARARs.
DNAPL:
Alternatives DN2, DN3A, and DN3B each provide equal protection of
human health and the environment. These alternatives reduce
contamination in the aquifer through active recovery, and they
result in ultimate destruction or reuse of DNAPLs. However, each
alternative will leave a significant amount of contamination within
the aquifer which must be addressed by an appropriate groundwater
alternative. Alternative DNl is not protective of human health or
the environment, since DNAPL contamination would continue to
migrate and further degrade groundwater and surface water.
Groundwater:
Alternatives GW3A, GW3B, and GW4 would provide equal protection of
human health and the environment and would reduce the concentration
of chemical constituents in the groundwater through a combination
of treatment and institutional controls. Alternative GW2 would
provide some protection of public health by preventing the
widespread use of the contaminated water. However, this
alternative would do nothing to prevent contaminated groundwater
discharges to area surface water, putting both public health and
the environment at risk. Alternative GWl is not protective of
human health or the environment.
32
-------
8,.,2
COmDliance with ARARs
This criterion considers whether a remedial alternative meets all
Federal and State ARARs. Unless a waiver is justified, the
selected remedy must comply with all chemical-specific, location-
specific, or action-specificARARs.
DNAPL:
Alternatives DN2, DN3A, and DN3B would be designed to comply with
all Federal and State ARARs.' Alternat~ve DN3B is not required to
comply with RCRA Land Disposal Restrictions or Minimum Technology
Requirements under 40 CFR Part 268 because this alternative
utilizes a TU for storage of DNAPL. Alternative DNl would not
comply with ARARs, since contamination in the aquifer currently
exceeds ACLs and discharges ,of DNAPL into local surface water could
result in viol,ations of surface water standards. '
Groundwater:
Alternatives GW3A, GW3B, and GW4 would comply with all ARARs.
Neither Alternative GWl nor GW2 would comply with ARARs since
groundwater contamination above remedial goals would remain in the
aquifer.
Because Alternatives GW1, GW2, and DNl do not comply with the 'two
threshold criteria, they will not be considered further in this
analysis,.
8.3
Lona-Term Effectiveness and Permanence
This criterion assesses whether a remedial alternative would carry
a potential, continual risk to human health and the environment
after the remedial action is completed. An evaluation is made as
to the magnitude of the residual risk present after the completion
of the 'remedial actions as well as 'che'adequacy and rel~ability'of
co.ntrols that, could be i:i\plemenced to monitor and' manage the
residual risk remaining. '
DNAPL:
Alternatives DN2, DN3A, and DN3Bwould all leave behind a
significant amount of residual DNAPL in the saturated zone which
will need to be addressed by a groundwater alternative. However,
each of the alternatives provides for maximum DNAPL removal to the
extent practicable and either treatment or reuse of thete~ove~ed
creosote.
Groundwater:
In cornbinatlon with a DNAPL recovery alternative, all three
remaining groundwacer alternatives represent permanent solutions to
the groundwdcer contaminatlon ae the ACW site. However,
,39
-------
Alternative GW4 provides an additional degree of effectiveness,
since treatment occurs both above ground and within the aquifer,
shortening the overall treatment duration. The long-term
effectiveness of Alternatives GW3A and GW3B would depend on the
ability of the extraction system to remove all of the contamination
from the aquifer, since treatment only occurs above ground.
8.4
Reduction of Tox~tY, Hobil;ty, or Volume throuah Treatment
This criterion assesses the degree to which a remedial alternative,
by utilizing treatment technologies, would permanently and
significantly reduce the toxicity, mobility, or volume of hazardous
substances at the site. The assessment focuses on the degree and
irreversibility of treatment.
DNAPL:
Alternatives DN2, and DN3A provide equal reduction in mobility,
toxicity, and volume through treatment. Alternative DN3B does not
require treatment, but provides for recovery and reuse of the DNAPL
as a product or BTU source rather than disposal as a waste. All
alternatives have the potential to mobilize contaminants through
the inj ection of surfactants and other agents. However, the
extraction well network can be designed to capture the mobilized
contamination.
Groundwater:
Alternatives GW3A, GW3B, and GW4 all provide a substantial
reduction of toxicity, mobility, and volume of contamination
through treatment. Because Alternative GW4 provides for treatment
of contamination both above ground and within the aquifer, EPA
expects this alternat~ve to provide a greater reduction in the
contaminant volume.
8.5
Short-Term Effectiveness
This criterion assesses the degree to which human health and the
environment would be impacted during the construction and
implementation of the remedial alternative. The protection of
workers, the community, and the surrounding environment as well as
the time to achieve the remedial response objectives are considered
in making this assessment.
DNAPL:
The short-term effectiveness of each of the three remaining DNAPL
alternatives ~s equivalent. Each w~ll ~nvolve temporary storage of
recovered DNAPL until suffic~ent volume has been collected for
cost-effective disposal. Normal short-term hazards associated with
well. installation and other construction activities will be
addressed chrough a slte-speciflc health and safety program.
" r.
'-I\J
-------
Groundwater:
During the construction phase, all three groundwater alternatives
would involve typical construction hazards and potential contact
with contaminated soils and groundwater during well installation.
However, these short-term threats to construction workers would be
addressed through a. health and. safety. program and the use of
personal protective clothing and equipment. Alternative GW4 would
provide better short.-term effectiveness because of the shorter
remediation time required to implement this alternative (5 years) .
8.6
ImDlementability
This criterion assesses the technical and administrative
feasibility of implementing a remedial alternative and the.
availability of" services and materials requ:lred 'during
implementation.' .
DNAPL:
The recovery technologies for all three DNAPL alternatives are
identical. All alternatives .are expected to leave behind a
significant amount of residual DNAPL in the saturated zone, which
will be addressed by a groundwater alternative. Alternative DN2 .
will involve extensive effort, including a test burn, to meet
reg'ulatory requirements for siting.. an on-site incinerator.
Implemen.tation of Alternatives DN3A and DN3B will depend on the
availability of off-site incineration or recycling. facilities,
respectively.' .
Groundwater:
Each of the groundwater alternatives would involve one or more
innovative technologies (UV~oxidation, biological treatment) which
would require treatability tests to verify their ability to meet
cleanup levels. Alternat.ive GW3A -would require the contractor to
obtain an NPDES permit for discharge to Pensacola Bay. Finally,
all three alternatives would involve extensive negotiations with
landowners to obtain access and easements for installation of
extraction wells ar.d distribution system piping.
8.7
Cost
This criterion assesses' the capital costs, operation and
maintenance costs, and total present worth analysis associated with
implementing a remedia'l alternative. The capital cost.s are divided
lnto direct costs and indirect costs. Direct capital costs include
construction costs, equipment costs, and site development costs.
Indirect capital costs lnclude engineering expenses and contingency
allowances. Operation and maintenance (O&M) costs are post-
construction costs necessary to ensure the continued effectiveness
of a remedial action.
41
-------
DNAPL:
Alternative DN3B is the most cost effective DNAPL alternative
because is provides equal protection as the other alternatives at
a lower cost. Alternative DN2 is the next most cost effective
alternative, followed by Alternative DN3A.
Groundwater:
Alternative GW4 is the most cost effective groundwater alternative
because it provides a greater degree of effectiveness and shorter
treatment duration at a lower cost than the other alternatives.
Alternatives GW3A and GW3B provide similar protectiveness at
similar costs.
8.8
State Acce~tance
This criterion assesses the technical and administrative issues and
concerns the state may have regarding each of the remedial
alternatives. FDEP and its predecessor, FDER, have been the
support agency during the RIfFS process at the ACW site, providing
input into all activities conducted by EPA. Based on discussions
with FDEP staff, EPA anticipates that the State's concurrence is
forthcoming. However, a formal letter of concurrence has not yet
been recei v"ed.
8.9
Community Acce~tance
EPA has conducted community relations activities throughout the
history of this site to advise interested persons of EPA's
activities and solicit community input. A summary of EPA's
responses to significant oral and written comments received during
the public comment period is provided in the Responsiveness Summary
in Section III of this ROD.
9.0
SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the
detailed analysis of alternatives uSlng the nine criteria, public
comments, and the Administrative Record for the site, EPA has
determined that a combination of Alternatives GW4 and DN3B is the
most approprlate remedy for addressing groundwater contamination at
the ACW site. EPA antlclpates using a phased approach for
implementing the groundwater cleanup. The initial phase would
involve recovery of DNAPL contamination to the maximum extent
practicable (Alternative DN3B) to control a significant source of
contamination. The subsequent phase (Alternative GW4) will address
the remaining residual contamination in the aquifer, as necessary,
to prevent the migration of contamination to surface water.
An estimated 2 million gallons of DNAPL will be pumped from
extractlon wells at a comblned rate of about 100 gpm using enhanced
removal methods. The enhanclng agents lalkallnes, surfactants, and
42
-------
polymers) will be introduced into the aquif.er via injection wells
located just upgradient of the DNAPL zone. Additional aquifer
sampling, testing, and modelling will be required during remedial
design to further characterize the extent of DNAPL contamination
and to determine the appropriate location and nUmber of extraction
and injection wells. .
Recovered DNAPL will be dewatered and stored on-site in a temporary
unit (TU) until sufficient quantities have been collected to cost-
effectively transport the material for off-site recycling. Testing
of the recovered DNAPL will be done to characterize the chemical
composition of the material to be recycled to ensure that the
recovered DNAPLs will meet the acceptance criteria of the recycling
facility. .
The goal of the DNAPL recovery system is to. remove the maximum.
contaminant mass from t.he aquifer in the most. cost-effective
manner. Since additional characterization of the extent of DNAPL
contamination is necessary and significant uncertainty surrounds
the ability of any extraction system in recovering contaminant
mass, EPA cannot currently predict the duration of DNAPL recovery
system operation. Instead, EPA will collect system performance
data to evaluate whether enhanced DNAPL recovery should continue at
any or all of the following milestones: the 5-year review; upon
recovery of"2 million gallons of DNAPLi and/or at such time as EPA
determines that DNAPL recovery is no longer technically feasible or.
cost-effective.. ..
Following .termination.,of the DNAPL recovery system operation, EPA
will initiate the second phase of the groundwater remediation plan
which addresses the residual DNAPL and dissolved groundwater
contamination remaining in the aquifer. Using an estimated
porosity of 0.35, one pore volume of contaminated groundwater is
estimated to be 152' million gallons. Alternative GW4 involves
recovery and treatment of about 1.8 pore volumes of groundwater
using. a. combination. of in-situ and above-ground. biological
treatment. .
Groundwater will be pumped from extraction wells at a combined rate
of approximately 105 gpm to an on-site treatment facility
consisting of a dissolved air flotation (DAF) system, continuous
flow bioreactor, clarifier; media filter, and granular activated
carbon (GAC) columns (see Figure 5).. Groundwater will be treated
to the more stringent of the Federal or State MCLs shown in Table
9. Experience suggests that not all of the groundwater recovered
from. the aquifer can be reinjected, so an estimated 26 gpm of
treated groundwater will be discharged to a POTW.. The remaining
treated effluent (85 gpm) will then flow to a holding tank where
hydrogen peroxide and nutr~ents will be added prior to reinjection
~nto the aquifer in order to st~mulate in-situ biological activity.
..rm.y sludges generaced in the treatment train will be disposed off-
site, and the resldual DNAPLs recovered by the system will be sent
off-site Eor ~ecycling. .
4.3
-------
~
11)1-;:-:(11,'1':1)
, ,'-11'
: 1 'I DTi\'[ 10 \)
1>- :,),\'[ H,t
I
I
j
\"1.'1\':1\1' l
; ,l!:,1
,,~!'f\f1.'J l , N
, II.:,LJJ-'
IW, C:)f.1
ŁEPA
I' C'O.N~rIN!, -:),!1~1
I>- f'l nw ---
I IW\ 1\ I; V" - () r~
1,'ILl'I\,\n --
OIL i~1.11
FREE
I'PoOm 1("['
'~O
DNPl)f,
': f\CX: \:1':[\',
" I~!J 'J
-------~-~._--
BACJ..:W,.\.c;H
.~
r MCLTI-- -1
---'~'~~TF---- l_~\~~~R _J
M'TP':ATED
:-LUDGE Sl-'E'J'l'
~',~~rIt\G ~ARRO~ ~o
P.ECi EN t:P.i\TlO.\I
FILTEI~-~--J
PP.ESS
-- -,---
OI;WA'nJ~ED
SLCDGE TO
RCRA
1A\lOtILL
-1--~~~s~)<:;::;'flI Bl;)REYEDIATION
I ~CHr~!\,tATIC'
- FP.E:;H GAC
f;,\C
ADSORPTION
MONEORING
~TATION
I POTW
! m~r.HARGE
! 20 G PM
AMERICAN
CREOSOTE WORKS
PENSACOLA. FL
HYDROGEN
PEP.:J)JVI::
&
NUTRIENT
ADOI': {ON
HOLDI:--lG
TANK
-- 'I DIS2HARGE
TO
IN'':E~TIO~
WELLS
'- " FJIi GPM
\,/
FIGURE 5
-------
Table 9
MCLs and Surface Water QuaUty Standards for
Contaminants of Concern
Maximum Contaminant Levels Surface Water Quality
(ug/I) Standard (ug/I) '
contaminant or Concern State Primary Federal State Criteria Federal
Drinking Primary Clus m Criteriab
Water Drinking Surface
Standards Water Water-
Standards
Carcinogenic P AHs (total) -- -- -- -
Benzo(b and/or k)Fluoranthene -- -- 0.031 . 0.0311
Benzo(a)Anthracene -- -- 0.031 0.0311
Chrysene -- -- 0.031 0.0311
Benzo(a)Pyrene 02 0.2 0.031 0.0311
2-Methylnaphthalene -- -- -- --
Naphthalene. -- -- 26< --
Ac~thene -- -- 3< 2.700
Dibenzofuran -- -- 67< 17
Fluorene -- -- 30" 0.031
Phenanthrene -- -- 0.031 0.0311
Anthracene -- -- 0.3< 0.0311 .
Fluoranthene -- -- 0.2< 16"
Pyrene -- -- ..0.3< 0.0311
Bis(2-ethylhe~y I)Phthala1e 4.0 6.0 -- 3.4"
2-Methylphenol -- -- -- --
(3-andJor 4- )MClhylphcnol -- -- -- --
Phenol -- -- .4.600.000 4.600
. 2.4-Dimethylphenol -- -- 6.5< --
.
Pentachlorophenol 1.0 1.0 7.9 7.9"
1,2.4- Trichlorobenzene 70 70 -- --
Carbazole -- I -- -- --
QUlOoIi'ne I -- I 371< . --
-- I j.
:15
-------
Maximum Contaminant Levels Surface Water Quality
(ugll) Standard (ugII)
Contaminant or CODcern State Primary Federal State Criteria Federal
Drinking Primary Class UJ Criteriab
Water Drinking . Surface
Standards Water Water-
Standards
Benzene 1.0 5.0 71.3 71
Cis-l;1.- Dichloroethene 70 70 -- --
Methyl Ethyl Ketone -- -- -- --
Styrene 100 100 1,150" eo
Trans-l;1.- Dichlm>ethene 100 100 -- 140,000
Vinyl Chloride 1.0 2.0 -- 525
2,3,7,8-TCDD (Dioxin) 0.00000oo14< 0.00000oo3 0.OOOOOOO14r 0.00000oo 14
&
State of Horida surface water quality standards from FAC 17-302.560, January 5,
1993, unless otherwise noted.
b
Unless otherwise noted; the Federal water quality criteria for human health based
on a 10-6 risk level for carcinogens and assuming consumption of orgarusms (e.g.
fish) only are presented. Source of criteria was OSWER Publication 9234.2-
09/FS, June 1990.
c
State of Horida chronic toxicity values developed under Chapter 17-302.530(21)
and 17-302.530(62).
d
Federal water quality criteria for protection of aquatic saltWater species.
e
FDEP identified the dioxin drinking water standard in a letter to EP A dated June
4, 1993.
FDEP has adopted the dioxin surface water standard contarned in 40 CFR
131.36(d)(6)(ii).
No quantitative standard available for this compound
:~ F
-------
A conceptual extraction and injection well configuration is
provided in Figure 6. Additional aquifer testing and mOdelling
will be conducted during remedial design to further refine the
number a:1d location of extraction and inj ection wells. EPA
anticipates utilizing some or all of the DNAPL recovery and
injection wells as part of the final groundwater remediation
system.
since some of the elements of Alte~natives GW4 and DN3B overlap,
the combined cost of the alternatives is less than the sum of their
individual costs. The net present worth cost of the' preferred
alternative is $10,344,000 based on the assumption that the DNAPL
recovery system will operate for 5 years prior to implementing
Alternative GW4. The cost includes $4,498,000 in capital costs and
$789,000 in annual ,operation and maintenance costs for years 1-5
and, $660,00P for years 6-10. . .
The goal of this remedial action is to manage the migration of
contaminated groundwater; to prevent statistically significant
increases in contaminarits in surface water resulting from
groundwater discharges, and to prevent the use of the groundwater
through institutional controls ~ Based on information obtained
during the remedial investigations and the analysis of all remedial'
alternatives, EPA believes that the selected remedy may be able to
achieve this goal. However I groundwater contamination may be
esp~cially persistent in the imrriedicite vicinl.ty of the former
wastewater lagoons, where concent'rations are relatively high. The
ability to' achieve remedial goals (ACLs) at all points throughout
the plume cannot be determined until the extraction system has been
implemented, modified as necessary, and plume response monitored
over' time. If the selected remedy cannot meet the specified
remedial goals at any or all of the monitoring points during
implementation, the contingency measures described below may
replace the selected remedy for these portions of the plume. Such
contingency measures will, at a minimum, p.revent further migration
of the plume and include a' combination of treatment and containment
technologies. These measures are considered to be protective of
human health and the environment and are technically'practicable
under the corresponding circumstances.
The selected remedy will include groundwater extraction for an
est.imated period of 10 years, during which time the system's
performance will be carefully monitored on a regular basis and
adjusted as warranted by the performance data collected during
oPE:~ation., Modifications may include any or all of the following:
o
at individual we~ls where remedial goals have been attained,
pumping may be discontinued;
o
alternating pumplng at wells to eliminate stagnatlon points;
puise pumping to 3110w aqu~fer equilibrat~on and encourage
adsorbed contaminants to part~t~on ~nto groundwater;'and
0'
. 47
-------
L..:>"'" : i
"; ';,:>........-...... ! !
...,..,..::..,/ t ,';' . '~--.:.... I i G MBI ST
t.:':'~~ ,~- -::':':::'c.::::-...-... - ,.,., "-- \ '. - -~_.-&.-_.~.~~.
",--.--.---- K= ) 't -"':'. ~.._._,._... -..... --. --,
, ,.:"~j ; 1 '.:, -..._- ~~~: ,:
j! /.:". ~i 'I J . .,~ -. ~"j TRF.ATMENT .
, ! ;./ ! , ',E . 'i r ACILITY i
-I: ~ I
~J' ~ ! 1_.__- ~~-"" t L
,".' '-~-i .--- J1, i P~E 1 [~RE~ i i-I r
(;i '. :. !. i "i i Ii I
I I , 1 I I
'---"-" -.......,-. ...-.. '-- '~~ ~~ I i L
-~)J':i 1[11 Ii
. i:' i ! i ! :
.. -_..="'''' .
...T T.-' ;:r:.-\!.F.
:EPA
i . ('Ol'-(,EI' 1 1 .\1. (;IU)II'II\\,\n:R
I
, 1-'.,\11<,\(""" \'iI>RU'\.)J,:('llo'\
:-,( 'f' ,,\)~'t) .
.\'\.U:RI<'.\'\ nu:osol E \\'OR'-:S. 11'<'.
l"o''S.\C'OI .\. FI ()RID,'
FHa IRE 6
4/:1
-------
o
installation of additional extraction or injection wells to
facilitate or accelerate cleanup of the contaminant plume.
To ensure that remedial goals continue to be maintained, the
aquifer will be monitored at least annually at those wells where
p~ping has ceased.
If EPA determines on the basis of performance data generated during
system operation that certain portions of the aquifer cannot be
restored to meet remedial goals, all of the following measures
involving long-term management may occur, for an indefinite period
of time, as a modification of the existing system:
o
engineering controls such as physical barriers orlong-ter.m
gradient cont~ol provided by low level pumping as containment
measures; ....
o
chemical-specific ARARs will be waived for the cleanup of
those. portions of the aquifer based on the technic~l
impracticability of aChieving further contaminant reduction;
o
institutional controls will be provided/maintained to restrict
access to those portions of the aquifer (or affected surface
water) which remain above remedial goals;
o
continued monitoring of specified wells; and
o
. . .
periodic reevaluation of remedial technologies for groundwater..
restoration. .
The decision to invoke any or all of these measures may be made
during a periodic review of the remedial action, which will occur
at five year intervals in accordance with CERCLA Section 121(c).
9.i
Remedial Action Objectives
As part. of the FS process, EPA identified remedial -action
'objectives (RAOs) for groundwater at the site to serve as a basis
for determining cleanup. levels and appropriate response actions.
The specific RAOs for groundwater'are as follows:
o
Prevent ingestion of groundwater that contains concentrations
of compounds representing a total excess cancer risk greater
than 10-6, a noncarcinogenic Hazard Index greater than 1, or
concentrations which exceed Federal and State ARARs.
- .'
o
Management of migration of the pollutants beyond the existing
limits of the known contaminant plume.
Based on these R.~Os, EPA developed remedial goal options for
meet lng these ab] ect i ves in groundwater. Remedial goal options
-::ons idered inc 1 uded Federa l. and Stac.e MCLs, heal ch-based cancer
r:'isk levels (10'") I hea.lth-based noncarclnogen1.c rlsk levels (HI=l) I
49
-------
and CERCLA ACLs. The rationale for selection of the final remedial
goals for groundwater and other performance standards for the
selected remedy are provided in Sectlon 9.2.
9.2
Perfo~nce Standards
Based on the RAOs discussed in Section 9.1 and the risks identified
in the BRA, EPA determined that remedial action to treat
groundwater contamination was warranted. However, EPA further
concluded that since residents and busjnesses in the area of the
ACW site are connected to city water supplies which draw
groundwater from upgradient of the site, remediation to health-
based levels (e. g. MCLs and risk-based remedial goals) was not
necessary. For this reason, EPA developed ACLs under CERCLA
Section 121(d) (2) (B) (ii) which provide protection of surface water
potentiallY impacted by discharges of contaminated groundwater.
CERCLA Section 121(d) (2) (B) (ii) sets out the following criteria for
the use of ACLs at a Superfund site:
o
there are known and projected
groundwater into surface water;
points
of
entry
of
the
o
on the. basis of measurements or projections, there is or will
be no statistically significant increase of site-related
constituents from the groundwater to the surface water at the
point of entry or at any pOlnt where there is reason to
believe accumulation of constituents may occur downstream; and
o
the remedial action includes enforceable measures that will
preclude human exposure to the contaminated groundwater at any
point between the facility boundary and all known or proj ected
points of entry of the groundwater into surface water.
EPA believes that these criteria can be met by implementation of
the selected remedy. Based on geological and hydrogeological data
collected in the vicinity of the ACW site, EPA has determined that
there is a hydraulic connectlOn between shallow groundwater (above
20 ft. b.l.s.) and the drainage ditch on the Pensacola Yacht Club
property. Reglonal geological studies further suggest that deeper
groundwater (greater than 30 ft. b.l.s.' discharges into Pensacola
Bay some distance from the shorellne. Therefore, the first
statutory criteria for ACLs is met.
Next, the results of groundwater and sediment sampling near the
site suggest that, in the past, the discharge of contaminated
groundwater to the PYC drainage ditch has occurred, and
contaminants have accumulated in the ditch and in Pensacola Bay
sediments near the mouth of the di tch. However, surface water
samples collected from the dralnage ditch have shown Ilttle or no
organic cont~mination. If left untreated, contaminated groundwater
,j:.scr'0::.ges ,-:ould :-esulc::::e C8ntln'Je'J J.ccli.'C.ulatlon of
,~,~:1[.':.:",:.nant::) "-d ~he ::1::.[:::>' spc:.",e,,",=' ar.d pocential lmpacts to
~ .
-------
surface water quality. For this reason, EPA calculated ACLs (see
Table 8) using a computer model which, when achieved at the site
boundary, would ensure compliance with surface water standards at
the point of groundwater discharge to the drainage ditch.
Application of. these ACLs as groundwater remedial goals will
prevent statistically significant increases in surface water
contamin~nt.concerttrations once the ACLs are achieved at the point
of compliance for the aquifer, which 1.S the southern site boundary.
Therefore, remediation of groundwater to the levels in Table 8 will
meet the second statutory criteria for ACLs.
EPA will conduct monitoring of surface water in the PYC drainage
ditch and Pensacola Bay to confirm that no statistically
significant increases of site-related contaminants are occurring.
Additionally, EPA will install shallow monitor wells immediately
. upgradient of the PYC drainage ditch and int.ermediate and deep
wells. 'at the Pensacola. Bay sJ,1oreline, t.o evaluate whether
groundwater exceeds the surface water standards prior to discharge.
into the surface water body. Th~ State and Federa~ surface water
criteria which will serve as performance standards in these monitor
wells are shown in Table 9. These standards, while not considered
ARARs for groundwater, were used in the development of groundwater
ACLs and will serve as a measure of the performance of the remedial
action. .
The final CERCLA criteria. for application of ACLs at a site
requirestnat adequately enforceable 1nstitutional controls are in
place to prevent hUman exposure to groundwater contaminants between.
the site boundarY and the point of discharge to surface water. The
area in the vicinity of the ACW site is presently proposed as a
delineated area under Chapter 17-524.420, Florida Administrative
Code (FAC), to restrict the potable use of the aquifer. At this
time, requests for new potable wells are handled by the Northwest
Florida Water Management District (NWFWMD) on a case by case basis.
In November 1993, NWFWMD advised EPA and area water well
contractors that pursuant to Sections 40A-3.301 and 40A-3:504 of
the FAC II the District intends to seek denial of any. potable or
irrigation wel1 permit proposed in [the site] area. II EPA believes
that this is a sufficiently restrictive institutional control to
ensure that inappropriate potable uses of the groundwater will n9t
occur. To address the possibility of a proliferation of bootleg
wells in the site area, EPA will conduct a survey during each five
year review to determine if any illegal wells have been inst?l~ed.
Nine private non-potable wells exist in the immediate vicinity of
the site. The majority .of these ,wells are used for irrigation and
other non-potable uses., However; EPA believes that some or all of'
these wells may represent a potential source of exposure to current
or future residents if they are allowed to remain in service, since
groundwater will not be remediated to health-based levels. For
this reason, EPA will plug and abandon each well for which consent
is granted by the w'ell ovmer. During remedial design, 'EPA will
conduct a well survey in the area east of Barrancas Avenue and Pace
51
-------
Boulevard, south of Main Street, and west of South C Street to
determine if wells other than the ones shown below exist:
Location
705 South I St.
1608 W. Cypress St.
1509 W. Cypress St.
708 South G St.
1407 W. Sonia St.
809 South F St.
810 South J St.
1710 W. Cypress St.
916 South I St.
Uses
Heat pump
Not used
Irrigation
Irrigation
Not used
Not used
Irrigation
Irrigation
Irrigation
In addition to the statutory criteria outlined above, it is EPA
policy to apply ACLs at a site only when active restoration of the
groundwater to MCLs is deemed not to be practicable. Based on
EPA's experience with groundwater remediation at sites contaminated
wi th DNAPLs, and considering the pervasiveness of DNAPL
contamination at the ACW site, EPA believes that remediation to
MCLs at the ACW site would not be practicable. However, EPA
anticipates that the active remediation measures outlined in this
ROD, as modified during implementation based on performance data,
may be able to achieve the ACLs developed for the site.
10.0 STATUTORY DETERMINATIONS
Under CERCLA Section 121, EPA must select remedies that are
protective of human health and the environment, comply with
applicable or relevant and appropriate requirements (unless a
statutory waiver is justified), are cost-effective, and utilize
permanent solutions and alt.ernative treat.ment technologies or
resource recovery technologles to the maximum extent practicable.
In addition, CERCLA includes a preference for remedies that. employ
treatment that permanently and significantly reduces the volume,
toxicity, or mobility of hazardous substances as thelr principal
element. The following sections discuss how the selected remedy
meets these statutory requirements.
10.1 Protection of Human Health and the Environment
The selected remedy protects human heal th and the environment
through extraction and recycling of DNAPLs, extraction and
treatment of contaminated groundwater, and'implementation of
institutional controls to restr,ict future groundwater use. This
remedy will protect human health and the environment by restoring
groundwater to levels which, when discharged to surface water, will
not result in degradation of surface water quality above surface
water standards protective of both human health and aquatic
organlsms. Further protectlon of publlC health wl11 be provided
through the lmplementation of State-imposed permit restrictions on
construction of potable wells in the dellneated area identlfied
~nder Chapter 17-524 FAC. Flnally, che plugglng and abandonment of
'=,2
-------
existing non-potabl~ private wells in 'the vicinity down-gradient of
the site will prevent inadvertent exposure through incidental
dermal contact and ingestion of groundwater contaminants.
10.2 Compliance with ADDlicable
Requirements (ARns) .
The.selected remedy for groundwater will comply with all ARARs.
The major ARARs which apply to the selected remedy and other non-
enforceable guidance and criteria which are to be considered' (TBC)
are presented below:
or
Relevant
ADDroDriate
and
Federal ARARs
.0
Safe Drinking Water Act (SDWA)
40 CFR 141. .SDWA Maximum Contaminant Levels (MCLs) for
contaminants' of concern are relevant and appropriate for
treatment of water being reinjected into the aquifer.
o
40 CFR 144. SDWA underground injection control (UIC)
regulations are relevant and appropriate to the construction
and operation of injection wells for reinjection of treated
groundwater.
Clean Water Act (CWA)
. 40 CFR. 403. CWApretreatment reg~iations are applicable to
the off-site discharge of treated groundwater to a publicly
owned treatment works (POTW).
o
o
40 CFR 131. CWA Federal water .quality criteria are to be
considered for evaluation of "statistically significant"
increases of groundwater constituents in surface water.
These standards, while not considered ARARs for groundwater,
were used, in the development of groundwater ACLs and' will
serve as a measure of the performance of the' remedial action.
Resource Conservation and Recovery Act (RCRA)
o
40 CFR 262 & 263. RCRA generator and transporter requirements
are applicable to the off-site transport and recycling of
recovered DNAPL.
40 CFR 264.553. RCRA requirements for temporary units (TUs)
. are applicable to any tank used for DNAPL' is torage while
sufficient volumes accumulate for off-site recycling. .
Other Federal Regulations
o
o
Alternate Concentration Limits (ACLs), derived pursuant to
CERCL.Z\ Section 121 (d) (2) (B) (ii) . ACLs are applicable as
remedial goals for groundwater restoration in place of MCLs.
53
-------
State ARARs
o
Florida Surface Water Quality Standards, FAC 17-302. State
surface water standards are to be considered for evaluation of
.statistically significant" increases of groundwater
constituents in surface water. These standards, while not
considered ARARs for groundwater, were used in the development
of groundwater ACLs and will serve as a measure of the
performance of the remedial action.
o
Florida Primary Drinking Water Standards, FAC 17 -550.310.
Maximum contaminant levels are relevant and appropriate for
treatment of water being reinjected into the aquifer.
o
Florida Rules on Hazardous Waste Warning Signs, FAC 17-736.
Identifies requirements applicable to signs around perimeter
and at entrances of site. .
o
Florida UIC Regulations, FAC 17-28. State UIC regulations are
relevant and appropriate to the construction and operation of
injection wells for reinjection of treated groundwater.
10.3 Cost Effectiveness
The combination of alternatives DN3B and GW4 provides the maximum
reduction in risks to human health and the envlronrnent. at an
estimated cost of $10,344,000. The selected remedy combines the
least expensive yet most effective DNAPL and groundwater treatment
alternatives which provide treatment in the shortest period of
time.
10.4 Utilization of
Practicable
solutions
to
the Maximum Extent
Permanent
The selected remedy relies on the removal and treatment of a
significa~t amount of contamination in the aquifer to provide for
a permanent, lon~-term solutlon for groundwater restoration. While
contamination will remain in the aquifer above health-based levels,
the institutional controls called for in this remedy are currently
in place and enforced by the Northwest Florida Water Management
District. Additional permanence will be afforded when the proposed
delineated area surrounding the ACW site is final1zed by a rule-
making by FDEP. Finally, EPA's closure of existing privately-owned
non-potable wells will prevent future uses of contaminated
groundwater.
10.5 Preference for Treatment as a Principal Element
The selected remedy provides for maximum contaminant mass removal
from the aquifer by utilizing enhanced DNAPL recovery to remove the
separate creosote phase which 1S serving as a source for
groundwater contamination. Recycllng of the recovered DNAPL uses
~he recQvered material as c product, thereby preventing the need
54
-------
for disposal. Above-ground biologi'ca.l treatment of groundwater
will further reduce contaminant volume. Finally, the in-situ
biological treatment will provide continuing reduction of
contamination within the aquifer.
~l.O
DOCUMBN'l'ATION OP SIGNIPICANT CHANGES
The Proposed Plan for groundwater remediation at the ACW site which
was released for public comment in November 1993 identified a
combination of Alternatives DN3B and GW4 as the preferred
alternative for groundwater remediation. While no changes to the
overall remediation approach have been made, EPA has documented a
few significant changes below:
Plugging of private wells: Following issuance of the Proposed
Plan, EPA determined that. plugging and abandonment of existing
private irrigat10n wells in the ACW site area. wasneces.sary to .
foreclose any future incidental exposure to contaminated
groundwater. EPA representatives explained this addition to the
proposed remedy at the public meeting on December 2, 1993,
requesting comments on this and other elements of EPA's preferred
alternative. EPA will seek written consent from each individual
well owner before plugging any wells.
Change in dioxin ACL: Based on comments received from FDEP and.
other ~eviewers, EPA.has reevaluated' the use of the dibenzofuran
ACL for 2,3,7, 8-tetrachlorodibenzodioxin (TCDD) because of the
notable .difference in dibenzofuran and. TCDD toxicity
characteristics. ACL calculations demonstrated that chlorinated
dioxin compounds would not migrate more than about 300 feet
downgradient of the site even if dioxin was present at extremely
high concentrations. This is due to the low mobility and
solubility of dioxin in water. Since dioxin concentrations
detected in groundwater were very low (0.0092 ng/l TEQ), EPA has
determined that an ACL for dioxin is not needed. However,
applicable dioxin surface water standards will apply as performance. .
standards .in the PYC ditch. '. .
55
-------
AppeDdix A
"Dioxin Toxicity Equivalence Factors
-------
DIOXIN TOXICITY EQUIV ALENCY FACTORS
Comoound TEFs
Mono-, Di- and TriCCDs
2,3,7,8-- TCDD 1
Other TCCDs
2,3,7,8~PeCDD 0.5,
Other PeCDDs
'2,3,7,8-lixCDDs 0.1
Other HxCDDs
2,3,7 ,8-HpCDDs 0.01
Other HpCDDs
OCDD 0.001
2,3,7,8-TC;D~ 0.1
Other TCD~s
1,2,3,7 ,8-PeCD~ 0.05
2,3,4,7,8-PeCD~ 0.5
Other PeCD~s
2,3,7 ,8-HxCD~s 0.1
Other HxCDFs
2,3,7 ,8-HpCDFs 0.01
Other HpCD~s
OCDF 0.001
-------
III.". RESPONSIVENESS SOHNARY
-------
III.
RESPONSIVENESS StJMMARy
In accordaace with Sections 113 and 117 of CERCLA, as amended, EPA
has conducted community relations activities at the American
Creosote Works (ACW) site' to solicit community input and ensure
that the public remains informed about site activities. EPA l1.as
relied on a' number of' methods' for keeping the public informed,.
including press releases, fact sheets, public meetings,
establishment of an information repository, and public comment
periods.
The U. S. Environmental Protection Agency (EPA) held a public
comment period from November 12, 1993 to January II, 1994 for
interested parties to comment on EPA's Proposed Plan for addressing
groun.dwa~er contamination (Operable Unit 2) at the American
Creosote Works (ACW) site.' During the comment period, EPA
conducted a public meeting at the Sanders Bea'ch Community Center in
Pensacola, Florida on December 2, 1993. During this meeting,
representatives of EPA presented the results of the studies
undertaken at the site and EPA's preferred alternative for
addressing groundwater and dense non-aqueous phase liquid (DNAPL)
contamination.
A summary of EPA's responses to cormnents received during the public
comment period, known as the responsiveness summary, is required
under Section 117 of CERCLA. The responsiveness' summary also
provides a brief background of EPA' s community outreach efforts anc;l
the concerns of the community about the site. EPA has considered
all of the comments summarized in this responsiveness summary in
determining the final selected remedy presented in 'the Record of
Decision (ROD) for Operable Unit 2.
A.
Backqround of Community Involvement and Concerns
EPA's earliest community outreach effort was a press relea'se
related'to the emergency removal activities in 1983. Periodic fact
sheets were issued during, 1984 and 1985 to, update the community
concernin~ studies being conducted at the site. In September 1985,
EPA issued fact sheets and press releases announcing a public
meeting and comment period related to the proposed plan for
addressing source contamination at the site. Similarly, in 1989,
EPA issued a fact sheet and held a public meeting to discuss the
revised source control remedy. In 1990, EPA prepared an
Explanation of Significant Dlfferences (ESD) -notifying the public
of additional tasks that would be necessary to implement the 1989
ROD. 'Later, in March 1991, a'fact sheet was published,to advise
the public of the initiation of these site preparation activities
which included cap repair, drum characterization, fence repairs,
well closure, and building demolition.
Mor,e recently. EPA conducted a door-to-door survey in September
1993 in the neighborhood surrounding ,the site to update lts mailing
list. ,EPA' s Proposed Plan for Operable Unit 2 was sent to the
RS-l
-------
puqlic in November 1993, and the administrative record for the site
was made available in the public repository at the West Florida
Regional Library. A notice was published in the Pensacola News
Journal on November 28 and 30, 1993 advising the public of the
availability of the administrative record, announcing the opening
of the public comment period, and advertising the date of the
upcoming public meeting. A public comment period was held from
November 12, 1993 to January II, 1994 to solicit input on EPA's
preferred alternative for addressing groundwater contamination at
the site. In addition, EPA held a public meeting at the Sanders
Beach Community Center on December 2, 1993 to discuss EPA findings
and answer residents' questions.
Approximately 50 people attended the public meeting during which
several residents expressed concern about their health, citing
numerous cases of cancer and other conditions in the community. At
least three people requested that a health study of area residents
be conducted. Residents also registered complaints about the site
being overgrown, thereby providing potential hiding places for
criminals. One resident attributed drainage problems and flooding
to the site, furnishing EPA with photographs of flooding along Pine
and Gimble Streets. At least two citizens suggested that EPA was
wasting money in clean~ng up this s~te, but many of the residents
expressed support of EPA's proposed Plan for groundwater
remediation -.
EPA's responses to these concerns and those provided by m?il are
summarized in Section B below. Additionally, a transcript of the
public meeting was prepared by a certified notary public, and this
document is a part of the Administrative Record upon which the
remedy selected in the Operable Unit 2 ROD is based.
Following the issuance of the final ROD for Operable Unit 2, EPA
will continue to keep the community ~nformed about progress at the
site through fact sheets and lnformal information meetings.
Additionally, design and 'constructlon documents pertaining to the
implementation of Operable unit 2 will be placed in the information
repository at the West Florida Reg~onal Library.
B.
Summary of Malor Comments and EPA's Responses
Comments on Health and Risk Issues
1.
Previous health assessments conducted for the ACW site are
inadequate. A new tox~cological and epidemiological study
should be performed to include air pollution modeling and a
survey of existing and former resldencs.
EPA bas forwarded tbis request to tbe Agency for Toxic
Substances and Disease Registry (ATSDR) and tbe Florida
Department of Healtb and Rebabilitative Services (RRS).
85-2
-------
2.
Numerous' people in the comrnunityhave died of cancers and
tumors, and birth defects, thyroid, heart, and other health
problems have been identified that may be long term effects of
pollution from the ACW site.
This co.mment has been relayed to A'1'SDR and HRS, since tbe
evaluation of bealtb concerns associated with Dast. exposure
would be tbe responsibility of healtb agencies. BPA believes
tbat ~ immediate bealtb threats bave been addressed througb
the removal actio.ns at tbe site. 'l'be remaining long-term
threats posed by tbe site will be addressed by the proposed
grou.odwater remedy and the source control to be proposed later
this year.
3 .
Are the vegetables from residents' gardens safe? Previous
. vegetable sampling did not include . all the fruits and
vegetables consumed from local gardens over the years.
In November 1985, BPA collected s~les of pecans, mustard
greens, collard greens, and green peppers from six residents'
garde.ns west and south of the, ACW site. 'l'be results indicated
tbat tbe produce was not contaminated in spite of the fact
tbat surrou.oding garden soils were contaminated. Altbough
every type of vegetable grown in tbe area was not sa.zqpled, BPA
believes the s~ling provided a representative evaluation for
the vegetable .exposure patbway. '
4 .
,. .
. . . .
. .
Fish having tumors were routinely caught. from the local
waters. No fish were tested, and many residents ate mullet
and other fish caught from the Sanders Beach pier.
BPA bas not sa..m.pled fisb or other, marine animals from tbe bay
to date. However, BPA bas collected numerous surface water
and sediment s~les from Pensacola Bay. The surface water
was not contaminated, but some bay sediments contained
. concentrations of contaminants wbicb could be toxic to aquat;t.c
organisms. Studies to .eval.uate contaminant effects on aquatic
animals in tbe bay may be conducted in tbe future.
5 .
Is it safe for residents to breathe the air around the site
while mowing is done? Is the dust from Plne Street safe. to
walk' on, breathe, or dissolve in rainwater?
While workers may need to wear respiratory protection wbile
mQwing tbe site, tbe quantity.of dust generated as the mower
. passes each individual bouse' will not be sufficient to result
in healtb problems. Mowing will be coZlducted in sucb a way as
to direct clippings intotbe center of tbe site. Very little
dust generation is anticipated during implementation of tbe
groWJdwater remedy. However, air monitoring and dust
suppression .'WOuld be components or any source control action
which involves movement or significant amounts or contaminated
so'ils. EPA' S ofr-si ce soil saIllpling along pine Street
? .:; h- ~~
-------
indicates tbat, altbougb some contamination exists, tbe levels
are low enougb not to represent a threat from any sbort-ter.m
exposure.
6.
The current overgrown condition of the site provides hiding
places for criminals. The site should be secured and mowed.
BPA agrees and bas initiated a contract for mowing the site.
Additionally, new locks will be placed on tbe existing gates,.
and new signs will be posted to warn of site contamination.
'!'bis work is expected to be done in February 1994.
7 .
North winds blew air emissions from the ACW plant over the
neighborhood for 30 years. The incidence of lung cancer in
the neighborhood should be reevaluated to determine the true
risk.
This request bas been forwarded to A'l'SDR and BRS. BPA
collected air s~les in 1984 to evaluate tbe potential for
current exposure to air emissions from the site. The results,
reported in the NUS RI report dated January 1985, identified
the presence of 12 volatile organic cOJZU)ounds at very low
levels. However, tbe concentrations detected were 100 to
1,000 times lower than tbe 'l'breshold Limit Value for each
co~ound, suggesting that current air emissions from the site
do not represent a threat to human health.
8.
What is the main pathway for future exposure to contamination
at the ACW site? Is lt children eatlng sOll from the site?
Are my children safe, and is it safe to rent my home to
families with young children?
Tbe bigbest risks documented by BPA for any potential future
exposure were associated witb tbe regular ingestion of
contaminated groundwater. BPA's 1989 risk assessment
indicated that risks for both adults and children exposed to
off-site soil contamination fell within EPA's acceptable
cancer risk range of lx10-6 to 1x1 0-4. However, EPA' s most
recent off-site soil s~ling data indicates that dioxins are
present at levels above 1 ppb, wbich represents' an excess
cancer risk of greater tban 1xlO-4 (1 in 10,000). EPA
forwarded tbis soil data to ATSDR for review, and ATSDR
advised tbat no immediate action was necessa~, but tbat the
contamination should be addressed by EPA's long-term remedial
action. Parents should take the following precautions:
probibit children from trespassing on the ACW site itself;
encourage them not to play in or eat either on-site or off-
site dirt; and wash their hands and face immediately if they
do play in the dirt. However, occasional contact with
contaminated soils is not expected to present a significant
risk.
?S-4
-------
9.
10.
11.
'12.
13.
. ..,',
No serious impact on either human or plant life has been
documented to date.
Th'3 SuperfWJd legislatioD does Dot cbarge BPA with docWDeDting'
specific health effects iD individual hllmanll or other plllDt or
IIDi.mal sl'ecies. Rather, BPA must determine whethe,r actual or
tbreateDed releases oŁ bazardous substllDces from the site may
I'resent lID imminent lIDd substllDtial endllDgerment to l'ublic
health, welfare, or the environment. BPA'. environmeDtal
s~ling IIDd risk assessments have demonstrated tbat, if left
unaddressed, contamination from the site could pose a threat
to future residents IIDd the enviroDlD8nt.
The benzene people breathe each time they fill their gas tanks
is more of a human health hazard than exposure to the ACW site
conditions. Likewise, for the smoking,drinking, and eating
habits of all of us~ "
The risks associated with the
identified may ve~ well present
, greater than the risks related to
ACPI site. 'However, these risks
activ.:ities of individuals whereas
result from the actions of others.
everyday' activities you
heal th hazards which are
long-term e~osure to the
stem from the volunta%y
the risks from the site
What data does ,EPA and/or ATSDR have on the carcinogenic
history of former cr~osote plant workers anywhere in. the U.S.?
BPA' s prillJa~ mission in the SuperfUl1d program is ~o
investigate and respond to releases of'hazardous substllDces
iDto the environment. The Agency for Toxic SubstllDces lII1d
Disease Registry (A'l'SDR) maintains a registry of persOZlB
e~osed to hazardous substllDces IIDd a rAgistry of serious
diseases and illnesses iD perSODS exposed to .hazardous
substances in the environmeDt. This comment bas been
forwarded to A'l'SDR. '
, A 'comrnenter cited documentation stating that potential human
health and envirorunental impacts resulting from possible
discharge of contaminated groundwater into Pensacola Bay is of
relatively minor significance.
A later study of the sediments in the PeDsacola Yacht Club
draiDage ditch and Pensacola Bay (BPA, September 1991)
iDdicated that concentrations of certain PABs iD bay and
drainage di tch sediments pose an ecological ,risk,. '
What is the potential increase in life expectancy and the
expected reduction in' the lncidence of all cancers after
lrnplementation of the remedy? If you don't have a past record
of the epidemiology in the area, what will be your frame of
reference? '
RS-5
-------
BPA remedial action objectives for groundwater at tbe ACW lIite
are 1) to prevent ingestion of contaminated groundwater and
2)to manage tbe migration of pollutants beyond tbe exillting
limitll of tbe known contaminant plume. Succells in meeting
tbese objectives will be measured by tbe collection and
analysis of groundwater and surface water s~les and
comparison of tbese data to established performance standards
(i.e. ACLs, surface water standards). Since current residents
are not exposed to contaminated groundwater except througb
incidental contact from private wells, BFA anticipates little
or no significant reduction in cancer incidence resul ting from
tbe groundwater remedial action. BFA does not use life
expectancy as an evaluation criteria since so many otber
factors contribute to an individual's life expectancy.
14.
What studies have been made on the health status of rodents,
snakes or other mammals living on the ACW site?
BFA bas not conducted a healtb evaluation of on-site animals.
Instead, a substantial database of animal studie. whicb.
evaluate tbe effects of tbe various cbemicals found at tbe ACW
site is available to BPA in conducting risk assessments.
Since these studies are conducted under carefully controlled
conditions, any observed health effect. can be linked directly
to tbe cbemical being tested. In site specific IItudies,
conditions cannot be controlled as easily, and too many otber
factors could confound the study results.
Comments on EPA'8 Proposed Plan
15.
Several commenters stated chat the No Action alternative
should be selected for the site, since resldents are on city
water. Another suggested extracting the DNAPL plume if
possible and allowing nature co take its course.
BFA disagrees. While no one is currently drinking the
contaminated water, groundwater contamination could pose a
risk to future residents through incidental ingestion of water
from private wells. In addi.tion to public healtb, BPA is
concerned with protection of tbe environment. If not
addressed, contaminated groundwater could continue to migrate
into surface water (Pensacola Bay) and potentially im,pact both
bumans and aquatic organisms. EPA's selected remedy does call
for initial DNAPL removal. However, experience suggests tbat
even enbanced recove~ technologies bave limitations in the
percentage of DNAPL tbat can be removed. Since a significant
fraction of contamination is expected to remain in tbe aquifer
following enbanced recovery operations, BPA believes that tbe
in-situ/ex-situ groundwater treatment system will be needed to
acbieve remedial goals.
RS ::c
-------
~
1c
EPA .should evaluate whether the surrounding residents should
be relocated durJ.ng the cleanup. Were residents at the
Escambia Treating Company fETC) site relocated? '
BPA believes tbat relocation of residents is W1Decessazy
during im,plementation, of tbe groundwater ,re.r.aedy. Tbe'
groundwater treatment system can be designed to capture' and '
treat fugitive emissions. BPA will also conduct perimeter air
monitoring to ensure tbat airborne contamination above levels
of concern does not leave tbe site. 2'Wo residents were
t~orarily relocated during BPA's ~emoval activities at tbe
1l'l'C site, and tbey are now back in their bome.. BPA will
evaluate relocation 'at ACW more closely in relation to, tbe
O,perable ,Unit 1 remedy.
17.
Remediation of groundwater pollution' practiced by the EPA' has
proven to be ineffective. Your studies of 19 sites involving
pumping and treating for up to 10 years' show that there has
been little success in reducing concentrations to target
levels on a permanent basis.
Based on tbe study referenced, BPA bas adjusted it.
expectations concerning tbe ability to com.pletely restore
contam;{nated aquifers and revised its approacb to groundwater
remediation. Tbe proposed groundwater remedy for tbe ACW site
incoz:porates tbis new. tbii1Jcing. Specifically, tbe plan
proposes a pbased' approach to groW:1dwater remediation, calling
for DNAPLrecovery first, followed by a combination of pump-
and-treat and in situ technologies to address residual
contamination. Additionally, tbe selected remedy will be
designed to include careful monitoring and provi.ions for
modifying the remedy over time to .iJqprove its effectiveness.
Finally, BPA may make.tbe determination tbat modification of
remedial action objectives is warranted or tbat restoration of'
tbe aquifer to remedial goals is technically .iJqpracticable
bas'ed . on the data 'collected during remedial action
im,plementation. '
18.
Is there data to support that bioremediation works on heavier
, petroleum products known to be present at the site?
BPA's preferred alternative for addressing dissolved
groundwater contamination calls for the stimulation of native
. bacteria by tbe addition of nucrients and an o~gen source.
Treata,pility studies. performed by BPA determined that bacteria
native to site soil were available and capable of degrading
site contaminants. Specifically, the percent degradation of
43 com,pounds after 30 days of slurry pbase soil treatment
ranged from 15 percent for heavier PABs sucb as
benzo(a)antbracene to 100 percent for lighter fractions such
as 2-methylnaphthalene. BPA anticipates achieving higher
degradation rates in an' aqueous treatment. system.
Additionally, research by tbe USGS indicates that in-situ
P.S --,
-------
19.
20.
21.
22.
23.
biodegradation has been occurring naturally in the aquifer for
some time.
The option of recycling entails soil removal and transport
from the site. This would create problems of a magnitude
greater than the existing conditions.
BPA is not proposing to transport soils off-site for
recycling. Rather, deZ1Se non-aqueous phase liauids (DNAPLs)
will be recovered and sent to an off-site recycler. Host
recyclers either burn the DNAPL tor its Bro value or reuse the
material .s creosote for treating lumber.
Can benzene be recovered and sold?
BPA's plan basically entails recovering DNAPL, wbich contains
benzene, and allowing it to be used for fuel or wood
treatment. Tbe material C&.rU2ot be sold, but the costs of
recycling are much lower than the costs of treatment.
Alternative DN3B involves the use of surfactants, alkaline
agents, and polymers. Are these proven technologies? What
will. prevent these chemicals from uncontrolled migration?
will thermal methods reduce the viscosity of the DNAPL and
promote an increase in the pollutant level of the aquifer?
~n~aDced recovery technologies bave been used for ~ years
in the oil indust~, although their application in full-scale
DNAPL recovery systems is limited. However, the extraction
well network will be designed to prevent uncontrolled
migration of mobilized DNAPL. BPA's selected remedy does not
call for the use of tbermal recovery methods, wbicb can result
in uncontrolled vertical migration of DNAPLs.
The location of reinjectl0n wells associated with alternative
GW4 is not specified as it was for alternative GW3. will the
treated ground water be reinJected at the down gradient margin
of the contaminant plume?
Reinjection wells for the in-situ bioremediation system will
likely be placed within the contaminant plWlJe to ensure
distribution of nutrients and o~gen to bacteria where the
contamination is located. A conceptual well layout is shown
in the ROD. However, BPA will conduct additional field
studies and mOdeling to deter.mine the exact location of these
wells. ..
Won't the bacterla be pumped back up by the extraction wells?
Tbe extraction system will be designed to minimize tbe amount
of bacteria p~ed out of the aquifer so as to avoid short-
circuiting of tbe in-situ biological treatment.
RS-8
-------
24.
25.
26.
What facilities have been identified to accept recov~red
DNAPL? What assumptions were used in calculating the cost of
this alternative? What provisions will be established to
insure that adopting this alternative will not result in a
repeat of the American Creosote problem at another location.
BPA has. identi.fied at least .five .facilities which were
potentially capable o.f recYcling the ACW DNAPL. BPA used AD
average price of $1.15 per gallon .for cost,estJ.mating purposes
based on telephOZle bids. !I'o eJ1Sure proper JlLUJagement o..f
wastes, ~ o.f.f-site .facility receiving hazardous substADces
.from a SUper.fuzad site must be in cOJqpliADce witb its operating
permits.
The Northwest Florida Water Management District may not be
. able to enforce a ban on the installatipn of "bootleg" wells
in a restricted area near the site,. especially by out-of-state
drillers. In light of this problem, EPA should re""'visit the.
underlying assumptions that went into the calculation of the
ACLS? . .
BPA believes the Northwest Florida Water Hanagement District
is capable o.f enforcing its institutional bAD. However, to
address tbis concern, BPA will conduct neigbborbood surveys
period-ically to evaluate whether new "bootleg" wells .have been
installed.. A~ditional,ly, .BPA will seek to plug any existing
~lls.
How soon will the remedy be implemented?
EPA hopes .to award a design contract in 1994 and ini.tiate
construction activities by late 1995.
Commenta on Sampling Data
27.
.Based on historical 9ra1nage patterns in the area, off~site
soil sampling has been insufficient to adequately characterize
the extent of contam1nati6n. No mention is. made of
contaminated soi1s off-site.
EPA bas collected of.f-site soil slUlJ&)les from over 40 10catioJ1S
througbout the neigl:1borhood south and west of the ACW si te and
on tbe Pensacola Yacbt Club (PYC) property. Host sa1l1&'les were
c~llected to depths o.f 1 ft., but at least 8 samples .from tbe
PYC property were collected to deptbs of 2 .ft. Results from
. tbese investigations .have indicated .t.hat o.f.f~site Boils are
contaminated wit.h PABS, dioxins, and otber site-related
compounds. However, tbe contaminant levels represent a long-
term (chronic) threat ratber than an i.JDmediate (acute) bazard.
BPA will present plans for addressing soil contamination in
t.he Pro~osed Plan for source control (Qperable Unit 1), at
wbicb time tbe public will baveanother opportunity to comment
on tbe adequacy of soil s~ling. .
RS-9
-------
28.
29.
30.
31.
Groundwater sampling locations reflect current rather t.han
hlstorical dralnage patt.erns. Deep and intermediate wells
should have been sampled east and south of the site as well as
upgradlent to the west. and nort.h of the site.
During tbe numerous investigations conducted at tbe ACW site,
BPA, tbe u.s. Geological Survey, and BPA's contractors bave
installed and s~led over 100 wells in tbe vicinity of the
site. ""ell locations were selected based on both current and
former drainage patterns, h.1.stor.1.cal site operations, and
reg.1.onal groundwater flow direction. S~les were collected
from as far east asG Street (Ropke well), as far south as
Sanders Beach (800 ser.1.es), as far west as 11 Street (200
series), and as far nortb as Zarragosa Street (100 series).
What is the degree of cont.aminat.ion in t.he surface water and
sediment.s in Pensacola Bay? Are these areas going t.o be
addressed in Operable Unit 2?
BPA bas s~led surface water and/or sediments in botb
Pensacola Bay and tbe PYC drainage ditcb during investigations
in 1984, 1989, 1991, and 1993. Results have cons.1.stently
indicated little or no contam.1.nation .1.n Pensacola Bay. Data
from tbe upstream reacbes oŁ tbe ditcb ind.1.cated tbe presence
of a few contaminants, including bis(2-et~lbe~l)phthalate
(200 ug/l), benzene (0. 76J ug/l), and toluene (1.2J ug/l), but
a s~le collected from near tbe mouth of tbe ditch revealed
no organic contamination. Sediments in the PYC drainage ditch
are contaminated witb a variety of c~ounds, including PABs,
phenols, and dioxins. Toxic levels of organic c~ounds,
principally anthracene, fluorantbene, and pyrene, were
detected within tbe drainage ditcb and lower stratum of the
bay sediments at tbe moucb of tbe ditch. BPA will address
sediment contamination, if necessa~, in eitber tbe Qperable
UIJit 2 ROD or a separate Operable Unit 3 ROD.
Has the EPA ever analyzed and compared the cont.aminants in
run-off water both nor<:h and south of t.he site so as to
distinguish the amount. of pollut.lon from normal run-off versus
the contribution from the ACW site?
EPA collected run-off samples from botb north and soutb of tbe
site in March 1991. Tbe sample from north of tbe site
indicated no contamination above detection limits. The two
samples south of the site showed no volatile organic
contamination. Semivolatile analyses detected a few co~ounds
below detection limits and AIJthracene at a level of 46 ug/l.
Both sldes of the yacht club dralnage ditch is lush wlth a
variety of plant growth. Some of the largest and healthiest
looklng oak and magnolla c. rees In Pensacola borders t.hlS
ditch. Is chis lush grow~~ consistent with the EPA portrayal
ct t~e pollucioG i~ the dlCC~~~
PS-L
-------
BPA frequently relies on the evaluation of stressed vegetation
in areal photographs to identify potential contaminant source
areas. However, this tecbnique provides no quantitative
information, so environmental sampling and laboratory analysis
are used to provide data on the level of conta.mination in
various media.
32.
The Proposed Plan lists maximum concentrations detected, but
the sampling location is undisclosed. What was the location?
How many samples over what time period were analyzed from each
location? What was the average contaminant level?
The higbest. concentrations of polynuclear aromatic
hydrocarbons (PARs) were found in well 340, located on-site
just soutb of tbe former sludge lagoons. . This well was
drill,ed to a dept:b of 39.8 ft . The bigbest levels of
pentachloropbenol and dioxin were' detected in well 380,
located ~ext to well 340 and drilled to a depth of 77.3 ft.
The maximum concentration of benzene was detected in well 480,
located just ~ortb of the Pensacola Yacht C~ub and competed at .
a deptb of 80.4 ft. The Baseline Risk Assessment, located in
Volume 5 of tbe Administrative Record at. tbe Pensacola
library, provides a good summary of tbe groundwater data for
the site, including n'umber of slUllS'les, locatio~s, and average
concentrations.
33.
Forty"""eight percent of the" listed contaminan.ts are. not
carcinogenic. Is the listing made for the purpose of alarming
a lay person? .
Ca.ncer is only one of tbe .many heal tb effects wbicb may resul t
from exposure to chemicals. Other effects caused by exposure
to non-carcinogenic c~ounds (eg. napbtbalene) may include
nausea, beadacbes, skin rashes, cataracts and otber eye
disorders, kidney damage, and retarded cranial ossification
(scull bardening) and heart development in tbe offspring of
.exposed individuals. .MUch of the toxicity information BPA
relies upon to assess heal th effects comes from animal
studies, since data for humans is often not available.
34.
The numbers listed for PCP and dioxins/furan are confusing.
Please elaborate?
The concentrations of PCP and dioxin detected in .site
groundwater exceed drinking water Maximum Contaminant Le~els
(HCLs) . However,. since no one' is currently drinking the
water, BPA calculated alternate concentration limits (ACLS)
which, when met in the aquifer, would ensure com,pliance with
surface water standards where groundwater discharges to the
PYC di tch and Pensacola Bay. The ACLs for PCP and dioxin
indicate that existing levels of these com,pounds in the
aquifer probably do not present a threat to surface water.
t"""\"'" ~...,
K':;'- ~.~
-------
35.
36.
Was the PCP used at the site in the form of the
insoluble pentachlorophenol or the water soluble
potassiurn-pentachlorophenate? It makes a
difference in the mobility of the compound.
relatively
sodium- or
tremendous
BPA information on actual operations at tbe ACW lIite ill
limited. However, s4llJPling of all media at tbe lIite ball
revealed tbe widespread prellence of PCP, but none of the
pentacbloropbenate C~Oundll bave been detected.
Have there been any studies completed by EPA to follow up on
the 1984 preliminary USGS work studying contaminant impacts on
aquatic life in Pensacola Bay?
BPA com.pleted a Dye Dispersion' and Sediment S4llJPling IItudy in.
1991 to evaluate contaminant dispersion patterns from tbe
moutb of tbe PYC ditcb into PeD.sacola Bay and to collect
additional sediment s~les. Results iD.dicated tbat lower
stratum bay sediments were cOD.taminated witb potentially toxic
levels of some organic com.pounds, so BPA will meet witb
natural rellource trullteell in tbe near future to discusil tbe
need for furtber IItudies. .
Comments about Real Bstate and Legal Issues
37.
38.
39.
Property owners should be held harmless and indemnified
against any future health-related claims if we sell or rent
our properties.
BPA bas D.O autbority to iD.demnify property ownerll for bealtb-
related claims made by tbird parties. However, based on the
results of tbe risk assessmeD.t and feasibility study, BPA
believes tbe groundwater remedy selected iD. tbill ROD iD.
conjunctioD. witb tbe source control (Operable Unit 1) remedy
to be selected later tbis year will fully address any bealtb
risks to tbe public. .
Property owners should be compensated for the depressed market
value caused by proximity to the ACW site and planned remed~al
action activities.
BPA bas no autbority to co~ensate owners for losses in
property value. Moreover, EPA's remedial action will likely
~rove tbe market value of tbe property by removing existing
contamination.
will EPA force people to plug and abandon thelr private wells.
EPA believes tbe groundwater in tbe vicinity of tbe ACW site
ca.n.not be restored to a level tlJat is safe for drinking water.
For this reason, tbe ROD calls for plugging and abandoning
existiIJg private wells. EPA plans to eIJcourage well owners to
voluntarily allow EPA to plug. their wells for cbeir own safety
RS-12
-------
, 41.
and for the safety of' future residents. However, IlPA may
investigate other means to effect well closure if necessar,y.
General Comments
40.
I have n~ver been notified of any public meeting regarding the
ACW site. EPA should ensure that the mailing list is .
accurate.
~ellPA'project manager conducted a door-to-door survey in
SeptBlllber 1993 to speak to res:J.dents and update the mailing
list for the ACW site. All residences soutb of ~in Street,
west of C Street, and east of Barrancas with discerDllble
addresses were added to tbemailinglist.bringing tbe current
mailing list to over 300 households.
Runoff from the site' floods Gimble and Pine Streets.
anything be done to prevent this?
Can
BPA's final remedy for Operable Unit 1 will include .. final
grading of the site and installation of drainage features to
prevent this type of runoff problem.
42.
Can the dirt roads and streets be paved?
43.
BPA has DO authority,to implement public 'works ~rovements
, such as these unless they relate directly to implementation of,
the selected remedial action.
Why is only part of the ACW site fenced? Site operations (and
therefore contamination) extended to F Street. The perimeter
fence needs to be extended.
BPA fenced the JDOst contJ8m.Jnated areas of the site wbicb posed
the greatest threat to human health. While otber portions of
the facility are contamina'ted, the riskS are associated with
long-term exposure rather than short-term, incidental exposure
by trespassers. When the Operable Uni t 1 remedy is
~Iemented, the whole site will probably be fenced.
44.
The nelghborhood should be declared a disaster area, making it
eligible for disaster aid.
BPA has no authority to declare "disaster areas." However,
BPA believes the best way to rectify the situation caused by
, 'past operations at the ACW site is to conduct remedial actions
to address tbe sbort-term and long-term risks associated witb
soil and groundwater contamination. .
45.
What is the total population and age distribution of all
people ~iving within a half-mile radius of the ACW site?
'RS -13
-------
In 1970, tbe residential population witbin a 1 mile radiull of
the lIite wall approximately 5,000. BPA doe II not maintain
information on tbe age distribution of tbe community.
46.
How many private wells exist within this radius? What is the
depth of each of these wells? Has the EPA determined the
contaminant level of these wells?
Based on pallt data and door-to-door lIurveYII, BPA ball
identified nine private wells in the site vicinity south of
Main St., between Barrancas Ave. and C Street. In addition,
a public 8upply well is located at the people'8 C~8tal Ice
Co. north of tbe 8ite on Government St. 'l'hill well ill
reportedly s~led annually. Other wells may exist in tbe
area. Most of the private irrigation wells are fairly sballow
(less than 20 ft.), but the ice company well is 190 ft. deep.
EPA sampled four well. in 1984, including the ice camp~
well. 'l'he rellultll indicated no organic contamination in three
of the wells, but two compounds (toluene and bi.(2-
etbylhexyl)phthalate) were detected below detection limitll in
the Savannah Condo well upgradient of the .ite (Nallo~ St.) .
Two other well. were sampled in 1988. The YachtsmaJ:1' s Cove
condominium well wall contaminated with benzene above the MCL,
110 thi~ well was plugged in 1991.
47.
What is the contaminant level in the air when well water is
sprayed during irrigation?
BPA has not determined what this concentration would be.
48.
What percentages of the well owners use their facilities
regularly for irrigation? What is the frequency of use via
spraying?
Based on discussions with known well ownerll, BPA estimates
that 5 of the 9 private wells identified south of Main St. are
used for irrigatioD. The frequency of use is u.nknown.
49.
How much money has the EPA spent to date on the ACW site?
AD estimated $2.3 millioD !:laB been B~ent by the Atlanta
office. This figure does not include expeDBeB incurred by tbe
BPA offices iD Athens, GA, Gulf Breeze, FL, and Cincinnati,
OH.
50.
The last EPA action at the ACW site left many drums, open
containers, shallow catch basins filled ~ith stagnant water,
created poles, and a large open dumpster filled with garbage
and water. Why wasn't the area cleaned up?
DuriDg 1991, BPA contractors cODducted a number of activities
at the site including treatability studies, building
demolition, drum sampling and segz-egation, fence and cap
c - _"1 "
.',0 1.."-1:
-------
repairs, well plugging, seeding and mowing. 2'he drums
containing low-level wastes sucb as drill cuttings and purged
groundwater were placed in a securely fenced area on tbe
eastern portion of tbe site. 2'he "catcb basins" are merely
tbe foundations of demolisbed buildings wbicb bave filled witb
rainwater. 2'he dumpster remaining at tbe site contai.as non-
basardous co.astruction debris. 2'hese areas of co.aceZ'D will be
. addressed during tbe O,perable DDit 1 remedial action.
51.
The site contains a sizeable open pool of some liquid.
hasn't this been covered? .
Why
BPA bas identified and stabilised tbe visible source areas &ad
waste .:Uqpoundme.ats at tbe site. ~ standi.ag liquids are
likely to be poDded rai.awater wbicb poses no tbreat to bWll&Z1
bealtb. .
RS-1S
------- |