United Slates
            Environmental Prot« Jon
            Agency
              Office of
              Emergency and
              Remedial Response
EPA/ROD/R04-86/007
April 1986
&EPA
Superfund
Record of
            Hollingsworth, FL

-------
                                    TECHNICAL REPORT DATA
                             /Please read Initrucnons on the reverie before completing)
 1. REPORT NO.
 EPA/ROD/R04-86/007
                              2.
              3. RECIPIENT'S ACCESSION NO.
  . TITLE AND SUBTITLE
 SUPERFUND RECORD OF DECISION
   llingsworth, FL
                                                            5. REPORT DATE
                       ApriT If),  IQflA
              I. PERFORMING ORGANIZATION CODE
 7. AUTMOR(S)
                                                            8. PERFORMING ORGANIZATION REPORT NO
 9. PERFORMING ORGANIZATION NAME AND ADDRESS
                                                            10. PROGRAM ELEMENT NO.
                                                            1 I. CONTRACT/GRANT NO.
 12. SPONSORING AGENCY NAME AND ADDRESS
 U.S.  Environmental  Protection  Agency
 401 M Street, S.W.
 Washington, D.C.  20460
              13. TYPE OF REPORT AND PERIOD COVERED
              	Final ROD
              14. SPONSORING AGENCY CODE

                       800/00
 13. SUPPLEMENTARY NOTES
   tBSTnACT
    The Hollingsworth Solderless Terminal Company  (HSTC)  site  is located in Fort
 Lauderdale, Broward County,  Florida.   The 3.5-acre site  was  in operation from 1968  until
 the company closed the  facility on October 1, 1982.   HSTC  manufactured solderless
 electrical terminals.   The manufacturing process  included  heat treatment in molten  salts
 baths, degreasing, and  electroplating.  For approximately  eight years, HSTC disposed of
 wash water and process  wastewater  contaminated with  trichloroethylene  (TCE), and/or
   ~vy metals into drainfields  adjacent to the manufacturing plant.   Disposal practices
    [the site have been clearly  documented; however, the amounts of TCE disposed of and
 rne exact locations and duration of disposal remain  undocumented.  The waste TCE was
 used both as a degreasing solvent  and for cleaning floors, equipment, etc.  Primary
 contaminants at the site include TCE, vinyl chloride, trans-l,2-dichloroethene, and to a
 lesser extent, nickel,  tin,  and copper.
    The selected remedial action for this site includes:  excavation, aeration and
 replacement onsite of volatile organic contaminated  soils  and the recovery of
 contaminated ground water from the sand zones of  the aquifer, with  treatment and
 reinjection into the aquifer.   Capital cost for the  selected  remedial action is
 estimated to be $653,730 with  O&M  costs approximately $364,215 per  year.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                               b.lOENTIFIERS/OPEN ENDED TERMS
                           c.  COSATI Field/Croup
Record of Decision
Hollingsworth, FL
Contaminated Media: gw, soil
Key  contaminants: Trichloroethylene (TCE),
  vinyl chloride, trans-l,2-Dichloroethene,
  heavy metals, VOCs
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS I Tins Rtporti
          None
21. NO. OF PAGES

          50
                                               20. SECURITY CLASS (Tliit pagti
                                                        None
                                                                          22. PRICE
      i 2220-1 (R«». 4-77)   PREVIOUS coiTION is OMOLCTC

-------
                                                         INSTRUCTIONS

    1.   REPORT NUMBER
         Insert the LPA report number as it appears on the cover of th« publication.

    2.   LEAVE BLANK

    3.   RECIPIENTS ACCESSION NUMBER
         Reserved for uie by each report recipient.

    4.   TITLE AND SUBTITLE
         Title should indicate clearly and briefly the subject coverage of the report, and be displayed pruinincnily.  Sol sul prepared in more than one volume, reprui the primary Mile, add volume
         number and include subtitle for the specific title.

    5.   REPORT DATE
         Each report (hall carry a date indicating at least month and year. Indicate the l>a>is on which n w;is selected (i-.f.. Jair  onunix a
        significant bibliography or literature survey, mention it here.

    17.  KEY WORDS AND DOCUMENT ANALYSIS
        (a) DESCRIPTORS • Select from the Thesaurus of bnginecrir.g and Scientilic Terms the proper aulliuri/<.-J u-rins that  identity the major
        concept of the research and are sufficiently specific and precise to be UM.-U  as index entries lor Laulupri):.

        (b) IDENTII'IERS AND OPEN-ENDED TERMS • Use identifier! for protect nann-s. code names, equipment designators, etc. C'sc open-
        ended terms written in descriptor form for those subjects for which no descriptor exists.

          to
        the public, with address and price.

    19. & 20. SECURITY CLASSIFICATION
        DO NOT submit classified reports to  the National Technical  Information service.

    21.  NUMBER OP PAGES
        Insert the total number of pages, including this one and unnumbered pages, but exclude distribution list, it any.

    22.  PRICE
        Insert the price set by  the National Technical Information Service or the Government Printing Office, it known.
EPA Pwm 2220.1 (R«v. 4.77) (R.».r»»)

-------
                            Record of Decision
                      Remedial Alternative Selection
Site:  Hollincsworth Solderless Terminal Company
       Fort Lauderdale, Florida

DOCUMENTS REVIEWED

I an basing my decision primarily on the following documents describing
the analysis of cost-effectiveness of remedial alternatives for the
Hollingsworth Solderless Terminal Company site.

     Feasibility Study for Hollingsworth Solderless Terminal Company.

     Feasibility Study Work Plan for Hollingsworth Solderless Terminal
     Company (summarizes all previous remedial investigation efforts)

     Sumnary of Remedial Alternative Selection

     Responsiveness Summary

     State of Florida review cements

     Staff recommendations

DESCRIPTION OF SELECTED REMEDY

The selected remedy includes:

     - Excavation, aeration and replacement on-site of volatile organic
       contaminated soils at the east drainfield of plant #1.

     - Recovery of contaminated groundwater from the sand zones of the
       aquifer, treatment and reinjection into the aquifer.

When this remedy is complete, there will be no continuing operation and
maintenance requirements.

DECLARATIONS

Consistent with the CcmprehelSsive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA), and the National Contingency Plan (40 CFR
Part 300), I have determined that the aeration of soils and recovery,
treatment and reinjection of groundwater at the Hollingsworth Solderless
Terminal Company site is a cost effective remedy and provides adequate
protection of public health, welfare, and the environment.  Ihe State of
Florida has been consulted and agrees with the approved remedy.

-------
I have also determined that the action being taken is appropriate when
balanced against the availability of Trust Fund monies for use at. other sites,
     Date                                          Jack E. Ravan
                                                   Reaional Administrator

-------
                             RECORD OF DECISION
                 SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
               HOLLINGSWORTH SOLDERLESS TERMINAL COMPANY SITE
                          FORT LAUDERDALE, FLORIDA
Introduction

The Hollingsworth Solderless Terminal Company (HSTC) Site was proposed for
inclusion on the National Priorities List (NPL) in October 1981 and was
included on the first official NFL published in December 1982.  The HSTC
Site has been the subject of a Focused Feasibility Study (FFS) conducted by
the REM II, Region IV Contractor, Camp Dresser & HcKee Inc.'(CDM).  A
formal remedial investigation was not conducted at the si^e due to the
large amount of site investigation data previously collected.  However,
additional site-specific soil and ground water quality studies and a ground
water modeling study were conducted by CDM prior to initiation of the
feasibility study in order to describe current site conditions.

A single decision document has been prepared to summarize remedial
alternative selection for remediation of the HSTC Site, and is presented
herein.

Site Location and Description

The HSTC Site is located at 700 NW 57th Place in Fort Lauderdale, Broward
County, Florida, as illustrated in Figure 1.  The site encompasses
approximately 3.5 acres.  HSTC operated at this location from 1968 until
the company closed the facility on October 1, 1982.  The HSTC facility
consisted of two buildings separated by NW 57th Place.  The entire facility
is bounded on the north and east by asphalt alleyways, to the south by NW
57th Court, and to the west by other properties which run west to Power line
Road.  The HSTC facilities have been labeled Plant No. 1 (the southern
structure) and Plant No. 2 (the northern structure).  Plant No. 1 was the
manufacturing plant where contaminants were generated and discharged into
the various drainfields.  Plant No. 2 was strictly an assembly and storage
                                                                     183/11

-------
                                                    - N -
                         BROWARO COUNTY, FLORIDA

                           FORT LAUOEROALE
  NOT TO
  SCALE
                                       . ' HOLL1NGSWORTH
                                       !  SOLDERLESS
                                         TERMINAL COMPANY
                       REM II
             GENERAL LOCATION MAP
HOLLINQSWORTH SOLDERLESS TERMINAL COMPANY
               FORT LAUOEROALE. FLORIDA	
FIGUHC NO.

-------
                                                           1
                   •OtlTX
                PIPI
       ASPHALT ALLEYWAY
       MPWtr ALLtTWT
                                         !• HOMTN
                                 SCAl
                                  •UNPACI tUCNAJUl
    fl.H. 57th PLACE
         VASTI »IS»OtAk PIP!   _
                                                    tAiT
                                                    OUAIHPItk
   • ••r
   li.M. 57th COURT
 JB

-------
 facility which did not utilize wet processes.  Figure 2 shows the relative
 between the  two structures  and the various waste disposal areas associated
 with  the operation.   The building which once was designated as Plant No. 1
 has been subdivided and is  currently being rented tc a variety of small
 industrial/commercial tenants.  The building designated as Plant No. 2 is
 currently vacant.

 Land  use in  the vicinity of the HSTC Site is a mix between commercial,
 industrial,  and residential.  The area immediately surrounding the site has
 a high  density of  medium and light industry.  The Fort Lauderdale Executive
 Airport is located approximately one-quarter mile to the west.  Seaboard
 Coastline Railroad is located east of the site, and Interstate 95 (1-95) is
 a few hundred  feet beyond the railroad.  There is a large residential
 community on the east side  of 1-95.  In general, this area of Fort
 Lauderdale is  heavily developed and is experiencing increasing development
 pressure.  The area  surrounding the commercial/industrial complex around
 the Hollingsworth  property  and the Executive Airport and well field is
 rapidly becoming a medium to high density residential area.

The nearest  wells  that are  part of the City of Fort Lauderdale's primary
water supply,  the  Prospect  Well Field, are located approximately two miles
 to the west  of the HSTC Site.  The Prospect Well Field includes 38
 functional wells (see Figure 3) located around the Fort Lauderdale
Executive Airport  and Prospect Lake.  The closest wells to the HSTC Site
are Wells 8  and 12.   All of the easternmost wells are within 0.25 and 0.5
miles of the• HSTC  Site.   Wells 1, 4, 10, and 13 are no longer used or in
existence (wells 1 and 4 are not shown in Figure 3).  These wells are
either  contaminated  or were destroyed by lawn maintenance equipment.
Although functional,  most of the wells in the Executive Airport area are
used only during periods of extreme conditions.  Host of these wells are
 contaminated with  volatile  organic compounds from a variety of industrial
 sources  in the area.   The locations of the well field wells are shown in
 Figure  3.
                                                                      183/11

-------
      LEGEND
              PROSPECT PRODUCTION WELLS

              HOLUNO8WORTH SITF
CD
CO
CO
u
m
®
              ABANDONED WELLS

-------
The Biscayne Aquifer, which is a highly permeable, wedge-shaped, unconfirmed
shallow aquifer  composed of limestone and sandstone, underlies the site and
is the primary source of drinking water for 3 million residents of South
Florida.  Both the Executive Airport and Prospect Lake wells tap the
Biscayne Aquifer for water supply.  The top of the aquifer is near the
natural ground surface and its base is approximately 250 feet below ground
surface in the area of the site.  The upper 60-70 feet of the aquifer are
primarily composed of fine to medium grained sands.  This zone is underlain
by a transition  zone of cemented shell and sandstone and finally by the
limestone which  forms the major water producing zone of the Biscayne
Aquifer.  The regional direction of ground water flow is southeast.

The Atlantic Ocean is located approximately five miles to the east of the
site and the Everglades lie about 10 miles to the west.  Cypress Creek
Canal is located approximately 1.5 miles north of the site and Middle River
Canal is located about 2 miles to the south.  The average rainfall for this
area is approximately 60 inches per year/ much of which comes in short,
intense thunderstorms during the summer months.  The site is located within
the 100 year flood plain and is topographically flat.

Site History and Enforcement Activities

From 1966-1982,  HSTC was in the business of manufacturing solderless
electrical terminals, consisting of a conductive metal portion and a
plastic sleeve.   The terminals were designed to attach by means of crimping
rather than by soldering.  The manufacturing process included heat
treatment in molten salts baths, degreasing, and electroplating.  The
primary contaminants of concern at the site include trichloroethene
(trichloroethylene), vinyl chloride, trans-l,2-dichloroethene, and to a
lesser extent, nickel, -tin, and copper.

For approximately eight years, HSTC disposed of wash water and process
wastewater contaminated with trichloroethene (TCE), and/or heavy metals
into drainfields adjacent to the manufacturing plant (see Figure 2).
Disposal practices at the site have been clearly documented; however, the
                                                                     183/11

-------
amounts- of TCE disposed of and the exact locations and duration of disposal
remain undocumented.  The waste TCE was used both as a degreasing solvent
And for cleaning floors, equipment, etc.

As early as 1977, the Broward County Environmental Quality Control Board
(BCEQCB) was aware of the HSTC operation and began investigating HSTC
disposal practices.  Between 1977 and 1980, HSTC supplied information to
BCEQCB concerning disposal practices, effluent quality, and proposed
modifications to their operation, designed to effect compliance with BCEQCB
standards.  The full potential for ground water contamination at the HSTC
Site was not realized until 1980 when BCEQCB discovered the use of an
injection well for waste disposal during a routine site inspection.  BCEQCB
was initially the lead regulatory agency.  The Florida Department of
Environmental Regulation (FDER) became aware of the problems at HSTC when
the county requested assistance from EPA under the Comprehensive
Environmental Response, Compensation and Liability Act (CERCLA) program in
June 1981.  At that time, HSTC also applied for RCPA interim status (Permit
No. FLD 004119681) for their electroplating operation.  This permit was
never utilized and was allowed to expire.  HSTC had no other regulatory
permits.  In November 1981, HSTC filed for Chapter 11 status under the
Federal Backruptcy Code.

Pursuant to CERCLA procedures, a Remedial Action Master Plan (RAMP) was
commissioned by EPA in 1982 as the first step toward site cleanup.  The
RAMP was prepared by the Region IV CERCLA contractor, Ecology and
Environment, Inc. (E&E), of Decatur, Georgia, based on data supplied by
HSTC consultants   In addition to the RAMP, several investigations were
conducted by consultants to HSTC.  These investigations were partially
controlled by the Federal court system, under provisions of Chapter 11 of
the Federal Bankruptcy Code.  The HSTC consultants include Enviropact, Inc.
(Enviropact) of Miami Springs, Florida, and Geraghty & Miller, Inc. (G&M).
of West Palm Beach, Florida.
                                                                     183/11

-------
To date,  field investigations and other studies of this site-have included:

    o  Installation and sampling of 20 temporary, onsite (PVC) monitor
       wells
                                            i
    o  Installation and sampling cf nine permanent offsite
       (stainless-steel) monitor wells

    o  Collection and analysis of 41 surface and subsurface soil samples
       for metals

    o  Collection and analysis of 13 subsurface soil samples for volatile
       organics

    o  Installation of 10 shallow, temporary observation wells for water
       table measurements

    o  Contaminant transport modeling of pollutants discharged onsite, in
       relation to nearby well fields

Enforcement Analysis

Hollingsworth Solderless Terminal Company owned and operated the facility
from 1968 until manufacturing operations were ceased in October 1982.  The
company has been operating as a Debtor-in-Possession under the provisions
of Chapter 11 .-of the United States Bankruptcy Code since November 6, 1981.
The site was placed on the National Priority List in October 1981.  Since
that time the company has attempted to be responsive to Agency requirements
for a Remedial Investigation/Feasibility Study, but has fallen short,
probably due to financial considerations.  The Agency completed the work
begun by the company to investigate the site and has completed the
feasibility study.  The company maintains that a no-action remedy would be
the appropriate site response, however they have indicated they may be
willing to conduct or fund a portion or all of the remedy if certain
conditions are met.
                                                                     183VU

-------
Upon  the  finalization of the Record of Decision, the Agency intends to
formally  notify the company of the selected remedy and initiate
negotiations with them  for the conduct of the remedy.  Negotiations with
the company will not exceed 60 days, thereafter if the company does not
formally  commit to perform the remedy with assurances that adequate funding
is available to complete the remedy in a timely manner, EPA will proceed
with  a  Fund financed Remedial Design/Remedial Action.

Current Site Status

In 1981 and 1982, 18 monitor wells were installed on the HSTC property to
investigate ground water contamination problems at the site as shown on
Figure  4.  These wells were generally 20, 50, 75, and/or 100 feet deep; no
offsite wells were installed.  In 1983, a monitor well (MW-1) and test well
(TW-1), both of which are approximately 250 feet deep, were installed for
conducting pumping/aquifer tests.  Ground water data from all of these
wells showed that TCE was present at concentrations ranging from <1.0
microgram per liter (ug/1) to 4,300 ug/1; dichloroethene was present at
concentrations ranging  from <1.0 ug/1 to 2,160 ug/1, and trichloroethane
was not present.  In general, the highest concentrations of contaminants
were found in samples collected from the 50 and 75-foot depths.  Contam-
inants  were not found in the test well.  However, all three of the afore-
mentioned contaminants were present in samples collected from depths
between 106 and 230 feet during construction of the monitor well, which is
located next to the east well cluster.  Multiple depth sampling was per-
formed  during construction of both the test well and monitor well.  Metals
(copper, tin, nickel, lead, and zinc) were analyzed for, but were not
present at measurable concentrations in ground water samples collected from
any of  the shallow or deep wells.  Since no offsite ground water samples
were analyzed, the extent of offsite contamination, at that time, was
unknown.
                                                                     183/11

-------


*2- NORTH FIELD-;

u.
"'
# v
ASPHALT ALLEYWAY
"~" ~ I I
PLANT ^B| PLANT
:; h rj h r^
J*2A
*2B
"

* PN5 ; '
TEST WELL * e r-H
jVV-1 	 *7 D1 *<
*PS9 \;*8 i
*PS5 . \ i
M P**/**
•J" N
* MONITOR WELL

1 	 1
.*. 57tn PLACE

j. i
02 PLANT *1
* B ^--^ E f


>
?P^/
" NOT TO
SCALE
to*
5
|
» MONITOR WELL\
W ?7th COURT MW— 1 ^
.n. 3/tn V.UUH i MVY I

REFERENCE: ECOLOGY AND
ENVIRONMENT, WC. - DECEMBER 1962


REM II
ONSITE MONITOR WELL LOCATIONS
HOLLINGSWORTH SOLDERLESS TERMINAL COMPANY
FORT LAUOERDALE. FLORDA
^K.
:
FIGURE NO.

-------
Also during 1981 and 1982, soil samples were collected from the known
contaminated areas and analyzed for copper, tin, nickel, and lead.  Most of
the samples contained various combinations of the metals at individual
concentrations in the 1-10 milligram per kilogram (mgAg) range.  However,
a number of the samples contained metals at concentrations in the 100-1,000
mgAg  range.  A majority of these samples came from worst case locations
(i.e.  near the discharge point in the electroplating wastewater drainfield
and the overflow discharge points).  In the fall of 1984, Bnviropact
collected soil samples from the overflow area north of Plant 2 and analyzed
them for total and extractable copper, lead, nickel, and tin.  In a major-
ity of the samples, metals levels were below detection (1 mgAg), for both
total  and extractable metals.  In the remaining samples, metals concentra-
tions  were in the 1-10 mgAg range, which are concentrations that are
likely to be found in soil under normal or ambient conditions.  In par-
ticular, the concentrations of lead and nickel, the two most toxic metals
that have been found onsite, were within the range of ambient conditions.

Due to the fact that the toxicity of tin, and copper, is low, and the fact
that these metals in addition to nickel should readily precipitate from
solution and become bound as hydroxides and/or carbonates in the limestone
formation, they do not present an environmental or public health threat via
the water supply.  Even if these contaminants reached the water supply
wells, they would be readily removed by the water treatment process.  Lead,
which was also found at the site, does not readily leach from soils and the
concentrations present in the soils are well below levels established as
cleanup criteria (1,000 mgAg) for other hazardous waste sites in south
Florida (e.g., Pepper's Steel and Alloys) where lead is a primary contami-
nant.  The cleanup criterion is based on the leachability of lead and
predicted concentrations-in the ground water.

In early 1985, nine additional offsite monitor wells were installed around
the HSTC Site.  These wells and seven of the older monitor wells were
sampled and the samples were analyzed for the priority pollutant volatile
organic compounds, including those previously found onsite.  The new wells
were installed in three clusters of three wells (25, 55, and 100 feet
deep).  Two of the well clusters are located downgradient of the site, one

                                     11
                                                                     183/11

-------
about  500  feet to  the southeast, and one approximately 200 feet to the
southwest.  Contaminants were not present in any of the off site, down-
gradient wells.  The third new well cluster, which was located slightly
upgradient of the  site, showed contamination, in the 55-foot well.  This is
most likely due to contaminants which were discharged between the Plant 2
buildings  and to the field north of Plant 2.  Of the seven older wells
sampled, the four  wells (cluster of 25, 50, 75, and 100 foot wells) at the
southeast  comer of Plant 1, next to the east drainfield, showed volatile
organic contaminations at concentrations similar to those reported in 1981
and 1982.  The primary difference between the two data sets is the presence
of vinyl chloride  at substantial concentrations (200-6,000 ug/1) in samples
collected  from the 25, 50, and 75-foot wells of the east well cluster
during the 1985 sampling event.  Apparently, vinyl chloride analyses were
not performed on samples collected in 1981 and 1982.  Vinyl chloride is a
known  carcinogen,  and it is a cannon contaminant of the industrial-grade
TCE used as the degreasing agent for various plant operations by HSTC.
Vinyl  chloride was not present in any of the samples taken from the offsite
monitor wells.

The recent ground  water analyses indicate that the contaminants, which were
originally introduced on the ground, have migrated a short distance primar--
ily in a vertical  direction, through the upper sand zone of the aquifer.
Migration of these contaminants is apparently being retarded at a depth of
50-70  feet below land surface (bis), in a zone where the formation changes
from sand to sandstone and cemented shell.  Since the current concentra-
tions  are very similar to previous concentrations, it appears that contami-
nants  have not migrated substantially in the horizontal or vertical direc-
tions  through the  sand zone.  This type and rate of movement is typical in
settings, such as  this, where the ground surface and ground water gradient
are essentially flat and where a majority of the surrounding area in imper-
vious.  In the limestone or production zone of the aquifer which occurs at
approximately 100  feet bis, water moves much more rapidly (300-600 feet per
year compared to 5-80 feet per year in the sand portion of the aquifer),
readily diluting and transporting contaminants offsite.  Considering the
                                     12
                                                                     183/11

-------
concentrations of contaminants in relation to the vast water .bearing and
storage capacity of the Biscayne Aquifer, the absence of measurable levels
of contaminants in the production rone at the site is not unexpected.

In the past, attention has been focused on the fact that the HSTC Site lies
within close proximity to the City of Fort Lauderdale's Prospect Well
Field.  A number of the easternmost Executive Airport wells have been
abandoned due to the presence of volatile organic contaminants, including
those found at the HSTC Site.  However, recent investigations and site
inspections by the Broward County Environmental Quality Control Board have
identified at least 12 companies surrounding the Executive Airport that use
degreasing solvents and dispose of their wastes in a manner that may be
directly impacting water quality in the Executive Airport wells.

In late 1984, COM performed contaminant transport modeling of the HSTC Site
in relation to the nearby city wells.  A number of pumping and discharge
scenarios were investigated.  The model presumed the worst case, most con-
servative set of parameters and still showed that the HSTC Site could not
be a source of contamination of the well field.  Some of the other indus-
trial sources identified by BCEQCB were factored into additional model runs
and these data showed that any of a number of the other sources could be
sources of contamination of the well field.  Currently, the Executive Air-
port wells are used only under extreme conditions; the Prospect Lake wells
operate at approximately 30 million gallons per day, and supply drinking
water for 150,000 to 200,000 residents and industries of the City of Fort
Lauderdale, Florida.

The results of the public health evaluation indicate that currently there
are no complete pathways -for exposure of the public by direct contact,
ingestion, or inhalation^of contaminants from the Hollingsworth Site, but
that the potential for future exposure does exist.  The primary route of
potential future exposure is via installation of private wells or indus-
trial supply wells downgradient of the site.  The primary contaminants of
concern for exposure via this route are vinyl chloride, TCE, and trans
1,2-dichloroethene.  Based on the potential for future use of contaminated
ground water and the fact that the Biscayne Aquifer is a sole source

                                     13
                                                                     183/11

-------
drinking water aquifer, the cleanup goals for ground water remediation at
this site were based on both the 10"  cancer risk factors and the State of
Florida primary drinking water standards.  These standards are summarized
as follows:



Contaminant
(ug/1)
Vinyl chloride
Trichloroethene
trans 1,2-Dichloroethene
10 u
Life-Time
Cancer Risk
Factor

2.0
3.2
None
State of
Florida
Drinking
Water
Criterion
1.0
3.0
None
Proposed
Maximum
Concen-
tration
Levels (MCLs)
1.0
5.0
70.0
.HSTC
Cleanup
Goal

*
1.0
3.2
70.0
* FR. Vol. 50, November61985.
Because there is no 10   cancer risk factor or state drinking water
criterion for trans 1,2-dichloroethene, the proposed MCL for this compound
has been adopted.  It should be noted that the trans 1,2-dichloroethene
will be removed by the preferred treatment process to levels well below the
cleanup goal to within the 1-10 ug/1 range.

The public health evaluation assumed that exposure to contaminated soil
could be either by ingestion or by dermal contact.  Both copper and tin
were present in a few soil borings at concentrations above backgound
levels.  -Inorganic tin and copper, at the concentrations found in the west
drainfield, are unlikely to present health problems under a most probable
ingestion scenario of 50-100 mg/day soil by children, or under worst-case
scenarios of ingestion of up to 500 mg/day.  Ingestion of an excessive
quantity (500-5,000 mg) of soil contaminated with copper at concentrations
present in the west drainfield (1,000-10,000 mgAg) might pose a slightly
increased health risk, namely irritation of the mucous membranes and pos-
sibly gastric upset.  Because the west drainfield is surrounded by a fence
and the fact that the property is isolated from residential areas, the
likelihood that a child would ingest contaminated soils at the HSTC site
is negligible.  Nonetheless, cleanup goals were developed for metals
                                     14
                                                                     183/11

-------
contaminated soils at the HSTC site.  However remediation of metals con-
taminated soils is considered an element of site remediation that exceeds
applicable cleanup criteria due to the concentrations present and the
negligible risk.

the cleanup goals for soil contaminated with metals have been established
based on the concentration of the metals in leachate from the soils (as
determined by an EP toxicity test), as negotiated between FDER and EPA in
1983.  The limit for each metal in the leachate has been set at 10 times
the concentration of the appropriate state water quality criterion.  The
cleanup goal for soils contaminated by volatile organics, primarily the
soils in the east drainfield, is 1 ogAg in the coil.  However, testing in
1984 showed that the current concentrations of VOCs in the soils in and
underlying the east drainfield do not exceed this level.  The primary
concern and reason for remediation of this VDC contaminated drainfield is
the presence of volatilized contaminants in the void space of the drain-
field and the shallow zone underlying the pavement.  Remediation focuses on
venting these trapped vapors by a passive system, in a manner that mini-
mizes exposure of workers and the public, and also minimizes the cost of
treatment.  During the process additional soil testing will occur to verify
that soil concentrations are below 1.0 mg/kg.  The standards and goals for
soils remediation can be summarized as follows:

Soils
Contaminant
Copper
Nickel
Lead
Total VDC
Maximum Contaminant
Concentration in
Leachate from
Cnsite Soils
21.7 mg/i*
0.3 mg/1
0.2 mg/1
Not Applicable
State of Florida
Water Quality
Criterion
1.0 ug/1
0.1 ug/1
0.05 ug/1
None
HSTC
Cleanup Goal
10.0 mg/1
1.0 mg/1
0.5 mg/1
1.0 mg/kg
* This value was reported for a sample collected from the Gaidry property
in 1982.  The area was resampled in 1984 and the highest concentration of
copper in the leachate was 0.2 mg/1.
                                     15
                                                                     183/11

-------
All of  these  cleanup  goals were used as a basis for developing and
evaluating  the various  remedial alternatives.  Several of the alternatives
include removal and offsite disposal of the aetals contaminated soil
despite the fact  that the levels of contaminants at the site do not
currently exceed  the  cleanup goals.  Remediation of metals contaminated
soils at this site is considered an element that exceeds requirements for
site remediation.

Since ground  water contamination at this site is the primary concern,
determining the extent  of contamination and establishing a target zone for
ground  water  remediation were important elements of the feasibility study.

The existing  database indicates that movement of VOCs in ground water
within  the  surficial  sands is primarily in the downward direction.  This
conclusion  follows the  reasoning that VOCs are relatively insoluble in
water and heavier than water such that, in the absence of significant hor-
izontal ground water  flow or obstructions to vertical movement, the VOCs
will slowly 'sink until  they reach a geological barrier or a zone of ground
water of the  same density.  Further, it is presumed that once the VOCs
penetrate the limestone aquifer where ground water flow is significantly
greater, the  contaminants are rapidly dispersed in both the vertical and
horizontal  direction.  The more rapid horizontal movement of water in the
production  zone of the  aqifer also enhances the vertical gradient via a
"chimney effect."

The localized'areas of ground water contamination onsite are potential
sources of  offsite ground water contamination.  Remedial action to remove
these zones of known  ground water contamination before mixing with the
ground  water  in the underlying limestone aquifer were examined.  Removal of
ground  waters from the principal water bearing zone of the Biscayne Aquifer
(100*250 foot zone) in  the vicinity of the site was determined to be not
feasible or necessary for the following reasons.

    o   The  relatively high transmissivity of the Biscayne Aquifer promotes
        rapid  dispersion and dilution of contaminants.
                                     16
                                                                     183/11

-------
    o  Attempts to adequately remove VDC contamination from the Biscayne
       Aquifer would require a regional water treatment program.  This site
       is currently a minor contributor to that contamination problem.
    o  The concentrations cf ccntar.inan'-T in the 100-250 foot zone of the
       aquifer onsite have been shown to r>e at or below the applicalle
       cleanup goals.

The area targeted for ground water remediation can be defined as the areal
and vertical extent of contamination by VOCs at concentrations above back-
ground concentrations and the ground water cleanup goals.  The maximum
depth to which volatile organic contamination was most recently detected in
the ground water is 75 feet.  The depth of the target area for ground water
remediation has been defined as the top of the limestone aquifer at the
sand-limestone interface.  The average depth to the top of limestone is
approximately 75 feet in the vicinity of the site.

The areal extent of contamination is poorly defined because of variations
in the degree of ground water contamination at different locations and
depths.  Based on the most recent ground water quality data, the offsite
monitor well clusters 3 and 8 shown in Figure 5 show no contamination.
Therefore, it is reasonable to assume a minimum and maximum areal extent of
surficial ground water contamination based on the known clean zones and the
known contaminated areas, and application of engineering judgement con-
cerning aquifer characteristics and the behavior of the contaminants at
this site.  Based on this analysis, two zones have been identified as
target areas for ground water remediation.  These two target areas are
shown in Figure 5.  The inner target area was constructed by drawing a
200-foot radius circle around the onsite monitor wells 7 and C, which are
the two 50-foot monitor wells that were found to be contaminated and are
the two locations proposed for ground water collection.  The larger target
area was constructed by"assuming a 400-foot radius of contamination around
each well.  The final configurations of the target zones were drawn to
encompass the circles at both well locations and define one area for each
radius.  The target areas encompass the entire area of the plant site
without including areas shown to have no detectable contamination.
                                     17
                                                                     183/11

-------
LEGEND
   LOCATION OF MONITOR
   WELLS
 SCALE:  1**400'
TARGET AREA BOUNDARY
 FOR REMEDIAL ACTION ON
  SURFICIAL
    CONTAMINATED
     GROUNDWATER

       MINIMUM ESTIMATED EXTENT
       OF CONTAMINATION

       MAXIMUM ESTIMATED EXTEN
       OF CONTAMINATION
                       REM II
TARGET AREAS FOR GROUND WATER REMEDIATION
HOLLINQSWORTH SOLDERLESS TERMINAL COMPANY
.	           FORT LAUDERDALE. FLORIDA
                   FIGURE

                      5

-------
It is probable that the 400-foot radius selected as the boundary between
contaminated and uncontaminated ground water is larger than the actual
areal extent of contamination.  Based on the available monitoring data,
contaminant properties, and soil and aquifer characteristics, the movement

of VOCs in the surficial sands is more likely to be in a vertical rather
than a horizontal direction.  Thus, a smaller area (200-foot radius) for

ground water remediation has been included as a reasonable estimate of the

probable extent of contamination.


Alternatives Evaluation


The primary objectives of the feasibility study are to:


    o  Prevent further migration of contaminated ground water in the
       aquifer by cleaning up existing contamination in the aquifer

    o  Remove the sources of contamination from overlying soils and
       drainfields


The following six remedial action alternatives were considered:


    Alternative 1 - No action

    Alternative 2 - Modified no action

    Alternative 3 - Offsite disposal of VOC and metals contaminated soils
                    at approved facilities with discharge of VOC
                    contaminated ground water to city sewer system for
                    treatment at a local WWTF

    Alternative 4 - Onsite treatment of VOC contaminated soils with
                    continued monitoring of the ground water

    Alternative 5 - Onsite treatment of VOC contaminated soils and ground
                    water with continued monitoring and recharge of treated
                    ground water to aquifer

    Alternative 6 - Onsite treatment of VOC contaminated soils and ground
                    water with continued monitoring, recharge of treated
                    ground water to aquifer, and excavation and offsite
                    disposal of metals contaminated soils
                                     19
                                                                     183/11

-------
 Initial  Screening of Alternative Technologies

 An  initial  screening of applicable alternative technologies was performed
 to  select those which best met the criteria specified in Section 300.68 of
 the National Contingency Plan (NCP).  This initial screening is illustrated
 in  Table 1.

 Detailed Evaluation of Alternatives

 After the initial screening, remaining technologies were assembled into
 six remedial action alternatives for further consideration.  Table 2
 provides a  summary of actions involved and costs for each of the six
 remedial action alternatives which are described in greater detail to
 follow.

Alternatives 1 &  2;  No Action and Modified No Action

The "no  action" alternative was rejected because the harm that the
contaminants could cause require that, at an absolute minimum, contaminants
must be  tracked and their location known to provide time to design and
 initiate a  response to the impending exposure.

The potential impacts of both alternatives are identical except that with
the modified no action alternative long-term monitoring would provide a
mechanism for .identifying future threats to existing receptors.  Currently
the monitor wells located to the southeast of the site between HSTC and the
nearest  residential area show that the ground water is free of VOCs.  If at
some time in the  future, monitoring shows that contaminants are migrating
toward the  residential area, an effort can be made to notify the public and
possibly restrict use of shallow wells in the area.

Both alternatives involve no soil excavation and no ground water treatment.
With the modified no action alternative ground water from two of the
 existing stainless steel monitor wells in the vicinity of the site and one
 additional well to be installed further upgradient will be sampled and
 analyzed on a quarterly basis for an indefinite period to monitor the
                                                                   •
                                     20
                                                                     183/11

-------
                                          TABLE 1
                          SCREENING ALTERWOTVE TECHNOLOGIES FOR
                            APPLICABILITY TO HCLLJNGSWCRTH SITE
                         HQLLEC3WORIH SOUGHLESS TERimftL COMPANY
                                 FORT LAUDEROALE, FLCKEA
                                          FEW II
Possible Technology
  Retained (R)
or Eliminated (E)
   Reason
 Eliminated
Soil Treatment or Disposal

   o  Disposal/containment in cnsite facility




   o  Disposal offsite at a RCRA landfill

   o  Cnsite incineration
   o  Encapsulation/capping

   o  Cnsite treatment

      -  soil flushing
      -  steam stripping (in situ)
      -  till and evaporate
      -  venting

Ground Water Containment/Extraction

   o  Containment (slurry walls, etc.)

   o  Extraction

Ground Water Treatment

   o  Activated carbon adsorbtion


   o  Air stripping

   o  Steam stripping
        R


        E
        E
        R
        R
        R
        E

        R
        R

        E
                     Site lies in the 100-
                     year floodplain; no
                     suitable location;
                     high water table
Not effective for a
majority of the
contaminated soilsj- not
cost effective
Low effectiveness and
high cost
Infeasible due to dept
to confining layer
                     (But, produces
                      concentrated waste
                      residue).
Too expensive and
energy intensive
                                                                                    183

-------
                                        (continued)
Possible Technology
o Reverse osmosis
o Ozonation
t
Retained (R)
or Eliminated (E)

E
E
Reason
Eliminated
Not effective for
volatile organics
Technical infeasi-
   o  Wet air oxidation



Ground Water Disposal

   o  Purap untreated water to nearest
      water treatment plant

   o  Treat and discharge water to ocean

   o  Treat and discharge to nearest surface water

   o  Treat and reinject water

No action (modified)
E

R

R

R
             bility,  cost and safety
             considerations

             Not effective at low
             concentrations; energy
             intensive
Too expensive, loss of
fresh water
                                                                                    183.

-------
                               1ARLC  ?

SUfWARY Or PfltlKMAI  RIMCUIAL  AC Ml*  Al MRNAHVCS ANO ASSOCIAIUI COSfS
              HOUINGSMORIH SOlOWtSS  IIHMINAL  COWAMV
                       TORT LMIOlRDAir.  »LOR IDA
                                RIM ||
Alternative
Ho. Criterion Components of the Rowed Ml Alternative I
1 tin Action Non«?
? No Action Installation of ow addition*! Monitor Met)
(modified) long-term Monitoring (II) years)
Abandonment of onstto Bonltur wells
IOIAL
J Offslte Disposal Abandonment of onslto pmnitor wells
(ncavation anrt offslte disposal of netals
contaMlnated soils
(iiravttlon and disposal of V(K contaminated
soils at CPA-approvd landfill
Rotovery jnd discharge of VOC contaminated ground
water to city sewer system for treatment
TOIAL
4 l)o>*s not meet Abandonment of onsltc monitor wells
applicable Onslte treatment of VOC contaminated soils
criteria, but (source control)
reduces threat long Icmi ground water Monitoring ( JO years)
IOIAL
Minimum Tost
present worth)
0
1 S.OOO
/ 4. (Mill
10. 01(0
t at .000
t lO.fMKJ
2SJ.4J4
61,1)6
I.607.6S?
l\. 121.2*2
I 10.000
s/. IM;
79.000
t 146.047
Hanimim Cost
(present worth)
0
t S. (Hid
M. IWO
10.000
t fl'1,000
t 10.000
7SJ.4I4
61.116
?.787,67?
tl.ll?.l
-------
                                                       TABU 2
                                                     (continued)
Alternative                                                                          Minimum Cost      Maximum Cost
    No.         Criterion         Components of the Remedial Alternative            (present worth)    (present worth)


    5         Mo^ts applI-        Abandonment of onslte monitor wells                  t   lO.O(M)         t    10.000
              cable criteria      Onslie treatment of VOC contaminated soils               5/.047             57.047
                                  OnsIte-treatment of VOC contaminated ground             608.JM            //7.SS3
                                    water via air stripping
                                  Recharge of treated ground water                        142.527            415.359

                                  TOTAL                                              t  1.017.945         tl .259.959


    6         txceeds appl I;-      Abandonment of onslte monitor wells                  t   10.000         t    10,000
              cable criteria      Onslte treatment of VOC contaminated soils               57,047             S7.04I
                                  Onslte treatment of VOC contaminated ground             608.371            m,SSI
                                    water via air stripping
                                  Recharge treated ground water                           142.S?7            4IS,IS1)
                                  Excavation and disposal of metals contaminated          251.434            251.434
                                    soils

                                  TOTAL                                                11.217.179         tl.511.19.1

-------
offsite migration of pollutants.  The 4-inch diameter, 90 tcr 100-foot deep,
former injection well located onsite, will be abandoned by properly
plugging and sealing the well with grout and bentonite to eliminate any
future contamination from indiscriminant during of wastes, and to comply
with state  regulations.  In addition, all of the existing onsite PVC moni-
tor wells which are not suitable for long-term ground water monitoring will
be abandoned according to state regulations.

With the no action and modified no action alternatives, contaminated soils
and ground  water will be left onsite in their present state.  The cleanup
objectives  will not be met and the soils will continue to be a source of
further contamination and the contaminated ground water will continue to
migrate according to local gradients.  The potential environmental impacts
associated  with these alternatives are limited to degradation of the
shallow zone of the aquifer and possible exposure of listed endangered,
threatened, and special status species in Broward County.  The Kite will
continue to violate the State of Florida ground water standards.

With regard to public health, two potential exposure routes of the public
to contaminants at or migrating from the HSTC site are direct contact with
contaminated soils and direct contact with contaminated ground water from
private water supply systems.  The potential for human contact with con-
taminated ground water at toxic concentrations from shallow private veils
have been characterized as low, however, the possibility does exist.  In
addition, the presence of ground water contamination at this site would
limit future- use of the ground water resource in this area, a highly
productive, sole source aquifer.

Implementing the "modified no action" alternative will not involve
obtaining permits, although certain EPA requirements have to be met.
Ground water monitoring of both upgradient and downgradient wells will be
required, and fences and warning signs at the site will have to be main-
tained.  The presence of contaminants onsite will have to be recorded on
the property deed which could limit future use or redevelopment of the
property if either no action alternative is selected.
                                     25
                                                                      183/11

-------
The  following  is a summary of costs for this alternative:

                                                   1st Year Operation
                                                   and Maintenance
                                  Capital Costs    (O&M) Costs	
New  Monitor Well                    $ 5,000
Abandon Onsite Wells                 10,000
Quarterly Sampling Analysis                          $ 7,800
Totals                              $15,000          $ 7,800
Total present worth cost
§ 10% discount rate for
30 years of monitoring -            $73,500
Total present worth cost »          $88,500
Alternative 3t  Offsite Treatment or Disposal

A remedial action relying completely upon offsite treatment and disposal
requires soil excavation and disposal at an approved landfill.  This alter-
native is based on excavation and hauling of approximately 50 cubic yards
of soils contaminated with VDC's to an EPA-approved landfill and 955 cubic
yards of soils contaminated with low concentrations of leachable metals to
a local landfill.  This alternative also includes recovery and and dis-
charge of ground water to a local sewage treatment plant for offsite treat-
ment.  In addition, all of the onsite monitor wells and the injection well
would be properly abandoned.

Excavation of contaminated soils, supplemented with qualified supervision
and laboratory analysis of soils, is an effective method for removal of all
contaminated soils onsite.  Shallow excavation work should not require
dewatering which eliminates requirements for dewatering equipment and
handling of contaminated ground water.

The recovery of contaminated water within the estimated target area for
decontamination by pumping alone (at 1,000 gallons per minute (gpm)) will
require the disposal of a maximum of 1,600 million gallons over a 3.5 year
period or a minimum of 800 million gallons over a 1.5 year period.  The
                                     26
                                                                     183/11

-------
 ground water  recovery  system is estimated to consist of two, 10-inch
 diameter wells with pumps and controls.  Recovered ground water will be fed
 to  the sewer  system by gravity flow.

 Collection  and treatment of contaminated ground water will continue until
 the influent  ground water meets the cleanup goals or until the system fails
 to  be effective.  Contaminated soils will be excavated down to levels to
 meet the cleanup  criterion for each contaminant of concern.  Excavated
 soils will  be replaced with clean fill material to restore the site to its
 original condition.

 The primary environmental impact associated with this alternative is the
 loss of fresh water/ground water from an area where salt water intrusion on
 the public  water  supply is a serious concern.  Dewatering of the area will
 not affect  any environmentally sensitive areas, such as wetlands, although
 it  nay temporarily result in vegetative stress in the near vicinity of the
 site.  The  impact on the native vegetation is expected to be minimal and
 recoverable.

 The potential for public health effects associated with Alternative 3
 occurs primrily during offsite transportation and handling of the con-
 taminated soils and to a lesser extent, transport of the ground water to
 the treatment plant.   Worker exposure during excavation of the VDC con-
 taminated soils is also a consideration, however, actual exposure and risk
 can be easily .controlled by following well established health and safety
 procedures  and closely monitoring for ambient VDCs during the operation.
Another factor that should be considered is the likelihood that the wastes
will become contaminants in the new environment (disposal area) in the
 future, in  the event that they are mismanaged.

The cost of ground water treatment and disposal offsite is primarily
dependent on  the  sewer service charge by the City of Fort Lauderdale.  A
discharge of  a minimum of 800 million gallons at a rate of $1.40 per gallon
 represent a total fee  of $1.1 million.  Other costs include installation
and operation of  the recovery system, installation of a force main to
 connect to-the city sewer, and ground water monitoring on a monthly basis.

                                     27
                                                                     183/11

-------
The  following  is a  summary of the total present worth costs of Alternative
#2:

                                                           1st Year
                                       Capital Costs       O&M Costs
Recovery Well  System                  §  99,659           $   43,426
Abandon Onsite Wells                     10,000               —
Untreated Water to WWTP                   34,375           $1,046,623
Excavate & Dispose  of all
     Contaminated soils                   314,S70               —
     Totals                             $ 458,604           $1,090,049
Total present  worth cost
@ 10% discount rate  to be
operated for 1.5 years to
treat the minimum target zone -                            $1,927,222
For  the maximum target zone (3.5 yrs) •                    $3,112,192

Alternative 4;  Action to Reduce Threat

Implementation of this alternative includes abandoning (grouting and
sealing) the existing 4-inch injection well and all onsite FVC monitor
wells, excavation and treatment of VDC contaminated soils onsite, and
continued ground water monitoring.

The  preferred  remedial alternative for treating VDC contaminated soils is
excavation, ventilation, and replacement.  The expected length of time of
ventilation to completely remove VOCs from the soil is dependent upon
several factors.  Under ideal conditions, i.e., a warm, sunny, and breezy
day, the process may require only a few hours of exposure.  Under less than
ideal conditions, the pjocess may take a few days.  Nonetheless, the time
of completion  is relatively fast and the process can be expected to be
effective because of the volatile nature of the substances.  The remedy
represents a method for eliminating a potential source of ground water
contamination.  At  the same time, any soil contaminated by substances not
amenable to this treatment could be easily segregated for disposal offsite.
                                     28
                                                                     183,

-------
The environmental impacts of implementation of this alternative include
vapor emissions and the potential for contamination of stormwater runoff.
Vapor emissions will not present a problem to local residents because of
dispersion and the travel distance to the nearest receptors.  Adequate pro-
visions to prevent stormwater runon and runoff will be required and nay
include stand-by coverings for the soil spreading area and curbing to elim-
inate the runon of storm water from adjacent areas.  Given proper precau-
tions there are no adverse health effects associated with this alternative.

This type of treatment process nay not be specifically regulated by local
agencies because of its relatively unique approach, although local regu-
latory approvals for utilization of city or county right-of-ways will be
necessary.  No forseeable problems are anticipated, provided that adequate
controls and specifications are included as part of the contract documents
for this activity.

The following is a summary of the costs associated with this alternative:

          Abandon Onsite wells                      $ 10,000
          Excavate and Treat VOC Contaminated Soils   57,047
          Continued Ground Water
          Monitoring (present worth)                  79,000
          Total Present Worth Cost                  $146,047

Alternative 5;  Meet the Minimum Required Criteria

Elements of Alternative 5, which conforms to the minimum cleanup goals,
are: properly abandoning the existing injection well and all other PVC
wells onsite, treatment of VOC contaminated soil onsite, treatment of VOC
contaminated ground water onsite, and recharge of treated ground water near
the site.  Many of the components of Alternative 5, such as abandoning
wells, treatment of soils, and monitoring of effluents and emissions have
been discussed in the text of the first three alternatives.  Therefore,
analysis of remedial actions involved in Alternative 5 will focus on
treatment and disposal of contaminated ground water.
                                     29
                                                                     183/11

-------
The preferred technology applicable to Alternative 5 for ground water
treatment  is  air  stripping.  An air stripping system will perform extremely
well given conditions  at the HSTC Site.  Removal of volatile organic con-
taminants  from water at low influent concentrations is common practice
today.  Removal of 99  percent of the contaminants is achievable.  Due to
the fact that the primary sections of an air stripping operation contain no
moving parts  and  the reliability of the equipment is good, implementation
of the stripping  procedure provides a means of relatively rapid and inex-
pensive cleanup of the contaminated ground water problem at the HSTC Site.
As proposed,  the  ground water treatment system will include two extraction
wells located near the two wells which show the highest concentrations of
contaminants.  Each well will be pumping at a rate of approximately 500
gallons per minute.  The ground water will be passed through the air
stripping  column  and then recharged via a network of 10 shallow recharge
wells located at  the circumference of the target zone shown in Figure 5.
Effluent from the treatment system will be monitored on a weekly basis.

Recharge of the treated ground water offers several benefits unique to tfirs"
technology, including:  reduction of the duration of treatment, minimal
effects from drawdown  during ground water recovery, and creation of a
ground water boundary  to deter inflow of contaminants from outside the
target zone.   Recharge of the treated water also preserves a significant
volume of  fresh water  in an area that is subject to severe droughts and
salt water intrusion.  Recharge via shallow wells eliminates losses via
evaporation.  .Recharge will raise the level of ground water in localized
areas around  the  recharge wells, however this is not expected to have
adverse impacts on surface drainage characteristics or vegetation.  Wells
will be carefully located to ensure that building foundations, roadways, or
other facilities  are not impacted by activities associated with ground
water recharge.   Since the ground water will be treated to comply with the
cleanup goals  before recharge, there will be no adverse environmental or
public health impacts.  The pumping and piping equipment associated with
the recharge  system is all conventional, relatively inexpensive, and will
require minimum maintenance.
                                     30
                                                                      183.J

-------
Operation of an air stripper poses no threat to individuals working on or
near the treatment equipment, however, the issue of vapor emissions must be
addressed.  Considering that typical air to water ratios in air stripping
columns are generally in excess of 10:1, the volume of air diluting the
effluent stream will reduce organic emissions sufficiently until external
air currents have the opportunity to dilute and disperse emissions to
levels well below the exposure limits.  Periodic monitoring will be con-
ducted to ensure that emissions pose no risk to the public or environment.

Once initiated the ground water treatment system will operate until the
concentration of contaminants measured in the influent to the system meets
the cleanup goals or until an analysis of the system performance confirms
that it is reaching the limit of its ability to withdraw contaminated
ground water, e.g., the recovery is no longer effective.  If the system
reaches its limit of recovery of contaminants before the cleanup goals are
met, an analysis of the need for further action will be conducted at that
time.

The duration of remediation is expected to be between 1 and 2 years.  The
capital and p&M costs for implementing the ground water recovery, treat-
ment, and recharge systems as described above, and the other elements of
Alternative 5 are presented below, along with the total estimated present
worth for treating the minimum (1 year) and maximum (2 years) target zones.
Abandon Cnsite Wells
Recovery Well System
Ground Water Treatment
    (Air Stripping)
Recharge System
Excavate and Treat VOC Soils
Totals
Capital Costs
$   10,000
    99,659
$  254,649
$  232,375
$   57,047
$  653,730
                                                           1st Year
                                                           O&M Costs
$ 43,426
$210,637
$110,152
$364,215
                                     31
                                                                     183/11

-------
Total present worth cost @
10% discount rate  for 1 year
to treat the minimum target
zone (1 year)

For the maximum target zone
(2 years)
-   51,017,945


-   $1,259,959
Alternative 6:  Exceed the Minimum Required Criteria


Remedial actions included in Alternative 6 are abandonment of the existing

injection well and onsite monitor wells, onsite treatment of soils contam-

inated with VOCs, onsite treatment of ground water contaminated with VDCs

and subsequent recharge of ground water via shallow wells, and excavation

and removal of metals contaminated soils for offsite disposal.


All aspects of this alternative were discussed in texts of the first four

alternatives.  The addition of remediation of metals contaminated soils

exceeds the cleanup goals for the project and therefore Alternative 6

exceeds the minimum criteria.


The following is a sunmary of capital and O&M costs for this alternative:
Abandon Onsite Wells
Recovery Well System
Ground Water Treatment
    (Air Stripping)
Recharge System
Excavate and Treat VOC Soils
Offsite Disposal of
    Metals Soils

Totals

Total present worth cost
§ 10% discount rate to
treat the minimum target
zone (1 year)

For the maximum target
zone (2 years)
    Capital Costs

     $   10,000
         99,659

     $  254,649
     $  232,375
     $   57,047

     $  253,434

     $  907,164
     $1,271,379
     $1,513,393
                                                           1st Year
                                                           O&M Costs
$ 43,426

$210,637
$110,152
$364,215
                                     32
                                                                     183/11

-------
Recommended Remedial Action

A critical part  of  the  feasibility study is to evaluate the remedial
alternatives and identify  the most appropriate and cost effective alterna-
tive which meets the remedial response objectives.  In addition to the
response  objectives, several other important factors are used to evaluate
each alternative.   These factors  include:  level of cleanup, reliability,
special engineering considerations,  implementability, environmental effects
(air, surface water, ground water, and soils), capital costs, operation and
maintenance costs,  institutional  considerations, and the time required for
implementation.  A  detailed evaluation was conducted by Camp Dresser 4
McKee Inc. and is presented in the feasibility study report.  This
evaluation is summarized in Table 3.

The "no action"  and "modified no  action" alternatives are unacceptable
solutions to the problems  at the  Hollingsworth Site, since they do not meet
the remedial response objectives  nor state law and may result in public
exposure to contaminants.  The shallow ground water at the site is contain--^.
inated with a carcinogenic, organic  compound that poses a potential future
threat to public health and the environment.

Alternative 3, which involves offsite disposal, would meet the objectives
of the response, however,  the cost is considerably higher than other alter-
natives that also meet  the objectives and would result in a significant
loss of fresh water and temporary dewatering of the area.

Alternative 4 does  not  meet the objectives and provides minimal remediation
via source control.  The existing ground water contamination would not be
addressed except by continued monitoring.

Alternative 5 is the preferred alternative because it meets the cleanup
goals and the objectives of the remedial response for the lowest cost using
proven technology.
                                     33
                                                                     183/11

-------
                                                                         TABU 1
                                                                      SOLOCRLCSS TERMINM.  COMPANY
                                                                 FORT LAIMRDAU, FLORID
                                                                          RIM II
Alternative
Capital
W.UOO)
1st yr.   Present*
(MM        Morth
Ul.OOO)  ($1.000)
Public Health Consideration
                                                                                        Environmental Effects
                                                                          technical Consideration
                   15        74        89       Does not meet any of the remedial
                                                response objectives.  Possible future
                                                contamination of residential water
                                                supply and public water supply.
                                                Present public health threat low.
                                                however, future worst-case situation
                                                Indicates unacceptable level of risk.

                  458     1.090      1.927       Meets remedial response objectives.
                                     3.112       Reduces public health threat at the
                                                site, but creates potential for
                                                exposure during transportation to an
                                                offslte disposal area.
                  146        --         146       Does not «eet the remedial response
                                                objectives.  Possible future contami-
                                                nation of private irrigation wells and
                                                public water supply from existing
                                                ground water contamination.  Elimi-
                                                nates source of *OC contamination.
                                                low to moderate risk of worker expo-
                                                sure during soil treatment.

                  653       364       1.01H       Meets all remedial response objec-
                                     l.?60       lives.  Reduces public health threat
                                                to acceptable levels.  Moderate risk
                                                associated with worker exposure during
                                                soil treatment.  Low to Moderate
                                                potential risk to workers during soil
                                                treatment results in low level air
                                                emissions ofVOCs.
                                                                         Potential migration of contami-
                                                                         nated ground water offslte nay
                                                                         result in contamination of
                                                                         private Irrigation wells.
                                                                         Presence of  contaminants might
                                                                         Impact future use of  the ground
                                                                         water.

                                                                         Permanent  loss of substantial
                                                                         quantity of  fresh water.  Re-
                                                                         location of  contaminants with
                                                                         the long-term potential for
                                                                         environmental release.  Poten-
                                                                         tial adverse effects  from
                                                                         dewaterlng the area via offslte
                                                                         disposal of  ground water.

                                                                         Potential migration of contami-
                                                                         nated ground water offslte may
                                                                         result In contamination of
                                                                         private irrigation wells.
                                                                         Presence of  contaminants might
                                                                         impact future use of  the ground
                                                                         water.
                                                                                                Does not comply with
                                                                                                state law
                                                                         Removes source of ground water
                                                                         contamination.   Alleviates
                                                                         current and future  potential
                                                                         for offslte migration of
                                                                         contaminants and contamination
                                                                         of private or public  water
                                                                         supply welts.  Conserves fresh
                                                                         water by recharge.
                                                                                                V(1Cs will be removed during
                                                                                                transit to the treatment plant
                                                                                                and ituring pre-treatment.  OM1
                                                                                                for qround water recovery
                                                                                                systra.
                                                                                                Must make provision for runoff
                                                                                                contalnwnt/diversion.  Passive
                                                                                                tr«Mbwnt with minimum energy
                                                                                                requirements.  Rapid effective
                                                                                                tre.itim.-nt.
                                                                                                Proven technology which oper-
                                                                                                ates at high removal efficien-
                                                                                                cy.  Short treatment perliHl;
                                                                                                one time cleanup, no waste
                                                                                                residue for treatment or
                                                                                                disposal.

-------
                                                                         TABU J
                                                                       (conttnuH)
Alternative
           1st Yr.   Present*
Capital    (MM        Worth
(JI.UOO)   ($1.000)  (It .(Ml)
Public Health Consideration
environmental  Effects
T"chnlr.al Consideration
                  907       364        1.771.     rxcerds  remedial  response objectives
                                      I.SIJ   •  l>y rnmvtng metals contaminated soils.
                                                lllmiiMl"s every  potential public
                                                health effect,  low to Moderate
                                                potential for worker exposure (tiring
                                                soil  treatment.   Results in low lev*)
                                                air emissions of  VOCs.  Additional low
                                                risk  exposure of  workers during excav-
                                                ation etc. of metals contaminated
                                                soils.
                                                                         Removes all source of content-
                                                                         nation.  Allevlatrs all nirrent
                                                                         and potential future offsite
                                                                         migration of contMinants via
                                                                         ground water and eliminates
                                                                         potential combination of
                                                                         private and pub)Ic water supply
                                                                         wells. Conserves fresh water by
                                                                         recharge.  Restores all areas
                                                                         of the site to clean condition.
                                                                         Offsite disposal of «etils
                                                                         contaminated soils could result
                                                                         In environmental release In the
                                                                         future.
                                                                          Proven technology which oper-
                                                                          ates at high trivtbnent
                                                                          efficiency.  Short treatment
                                                                          period; one tinr cleanup.   No
                                                                          waste residue for treabiwnl or
                                                                          disposal.
   Iwo costs are based on treatment of ground water within  the mlnlnum and eaxlnum target zones.
   For Alternative ?. the times are I.S and 3.5  years.  For
   Alternatives 4 and S. the tines are I and ? years.
                                                                                                                            JflV?7

-------
Alternative  6 meets and exceeds the objectives and is exactly the same as
Alternative  5, except  that it includes excavation and offsite disposal of
all metals contaminated soils.  Based on the types and levels of metals
present,  removal of these soils is not warranted since the public health
risks are minimal.

Community Relations

Two public meetings were held to inform the public of activities at the
HSTC Site.   Fact sheets were prepared for both meetings.  The second
meeting was  held to present the Draft Feasibility Study Report and to allow
for public comment.  The public comment period was extended-by two weeks to
allow additional time  for review and comment.  A responsiveness summary
outlining the results  of public conment is enclosed.  An information repos-
itory was established  at the main branch of the Broward County Public
Library in Fort Lauderdale, Florida.  When approved, this Record of
Decision  will be sent  to the repository,

Consistency with Other Environmental Laws

The recommended remedial action protects public health and welfare, and the
environment.  It is consistent with other related environmental laws and
requirements such as RCRA, Air Quality Standards, and Executive Orders
related to floodplains and wetlands.

As explained-earlier, the HSTC Site contains elevated levels of VDCs in the
ground water.  These levels may pose a threat to public health and the
environment, especially since ground water is used for drinking water pur-
poses.  The  reconmended_'treatment would bring the quality of the water
withdrawn from the study area to levels at or below those set by the clean-
up goals  to protect public health.  Thus, the recommended remedial action
will be environmentally sound with respect to ground water protection and
drinking  water quality.
                                     36
                                                                     183/1J

-------
With respect to air quality standards, the recommended alternative will
generate VOC emissions from air stripping towers.  However, these emissions
will be far below the levels allowed by the State of Florida (60 Ib/hr or
15 tons/yr).  A simple air quality dispersion model was used to calculate
the dispersion of VOC emissions from the air stripping column.  The results
showed that even under worst case atmospheric conditions, the concentration
of VOCs is substantially less than the threshold limit values for the vola-
tile organic compounds found onsite.  The air stripping facility will be
located in a commercial industrial area, at least a quarter of a mile from
the nearest residence.  A 40-foot stack will be used for discharge from the
air stripping unit to enhance dilution and dispersion and minimize the
potential for exposure of the public.

The HSTC Site lies within the range of several threatened, endangered, and/
or special status species; however, none are known to frequent the area.
The site is, like almost all of Breward County, located in the 100-year
floodplain.  However, several flood control structures in the area minimize
and control flooding, including the area proposed for air stripping facil-w
ities.  Also, building permits are issued by Broward County only if the
ground at the proposed structures is raised above the 100-year flood eleva-
tion before the structure is built on it.  In this case, the elevation of
the existing surface at the construction sites will need to be raised by
only 1 to 2 feet to ensure that the air stripping treatment facilities are
not built on the 100-year flood plain.

To the extent that contaminated ground water flows to or is in contact with
area surface water, it causes no known violation of any water quality
standards.

Operation and Maintenance

In addition to the $653,730 estimated capital costs required for the
recommended alternative, operation and maintenance (O&M) costs will be
incurred for the 1 to 2 year life of the project.  O&M costs pertain to the
operation of the air stripping treatment facilities, the ground water
recovery system, and the ground water recharge system.  These include costs
                                                                  •
                                     37
                                                                     183/11

-------
                   .•«.)  energy
for labor  (operator ti«).  «"«»

.nd ^i^Bt puc—t (fans

S364,215 per year,  the
                                      «»">•  «>«"als "^ suppU"'
                                              estimate.  * ^         ^         wiu
                                     «^P           ^

                                                                of
schedule
 initiate Remedial Design


 Begin Remediation


 Operate Remedy
                                  Upon reauthorization
                                  Of CERCIA

                                  10 months after
                                  notice to proceed
                                                           1-2 years
                                        38
                                                                        183/11

-------
                           RESPONSIVENESS SUMMARY
                       DRAFT FEASIBILITY STUDY REPORT
               HOLLINGSWORTH SOLDERLESS TERMINAL COMPANY SITE
                          FORT LAUDERDALE, FLORIDA
INTRODUCTION

The Draft Feasibility Study Report on the Hollingsworth Solderless Terminal
Company  (HSTC) Site, Fort Lauderdale, Florida was submitted for public
review and the subject of a public meeting held on August 23, 1985 in the
main branch of the Breward County public library in Fort Lauderdale,
Florida.  Following the public meeting, the public cement period began.
Typically, the public content period for a draft feasibility study report
is three weeks; however, at the request of the responsible party, the
comment period was extended an additional two weeks until September 27,
1985.  The following is a susnary of the questions and issues raised both
at the public meeting and in written comnents received from the responsible
party and others.  The questions or issues and answers presented herein
have been organized into general topics and are being addressed on that
basis.

1.   Cleanup Goals or Criteria
     The cleanup goals for ground water established in the draft
     feasibility study report were based on both the state drinking water
     criteria 'and the 10   life time cancer risk factor.  These criteria
     are applied to the site because the aquifer at the site is classified
     as a drinking water aquifer.  The cleanup goals for soils were based
     on state water quaiLty criteria and the results of EP toxicity
     testing.  Standards were set at levels in the leachate at 10 times the
     appropriate water quality criterion.

2.   Introduction of Pollutants into the Air from the Air Stripping Tower
     Preliminary air modeling of the situation at the HSTC Site and
     extensive modeling studies done at other air stripping sites in south
                                     -1-
                                                                      183/7

-------
     Florida have shown that the level of contaminants emitted into the air
     from air stripping columns is typically well below the current Clean
     Air Act standards and does not present a public health threat.
                                            i
3.   Locating Monitor and/or Recharge Wells on Private Property
     In the past, EPA has had good success in obtaining permission from
     property owners to conduct activities or construct wells which have
     been shown to be in the public interest.  A number of the recharge
     wells may be located on city, county, or state right-of-ways, in which
     case negotiations will be undertaken with the appropriate agency.

4.   The Area-Wide Ground Water Contamination Problem
     An area-wide ground water contamination problem in the Executive
     Airport area does not relieve the responsible party of responsibility
     for cleaning up the contaminants at its site.  The EPA, in
     coordination with the State and Breward County, has a substantial
     program underway at this time to identify other contributors to ground
     water contamination in this area.  The comment that EPA has listed
     area-vide ground water contamination on the NPL in Dade County is
     incorrect.

5.   The Contractor for Site Remediation
     EPA would like to use one of the firms that is already under contract
     so that remediation can proceed as quickly as possible.

6.   What Area will be Cleaned Up
     The purpose of remediation is to mitigate ground water contamination
     at the site.  For planning purposes, two areas were identified in the
     feasibility studyr  These two areas describe minimum and maximum
     target zones for ground water remediation based on the data which show
     that certain wells on site are contaminated.  The ground water
     collection and treatment system will be operated in a manner such that
     once the concentration of contaminants in the influent meets the
     criteria, treatment will be discontinued.  Therefore, only that area
                                     -2-
                                                                      183/7

-------
     where ground water contamination exists will be cleaned up, even
     though hypothetical areas that may be much larger than the actual zone
     of contamination have been identified for planning purposes.
                                            i
7.   Depth of Recharge Wells
     The recharge wells to be used to reintroduce treated water back into
     the ground water system will be approximately 20 feet deep.  Shallow
     recharge wells such as these are conmonly used in south Florida for
     storm water, and heating and air conditioning system water disposal.

8.   Length of Project
     Based on the hypothetical target zones of contamination identified in
     the draft feasibility study and a withdrawal and treatment rate of
     1,000 gallons per minute, it will take approximately 1 year to collect
     and treat the ground water within the minimum target zone, and
     approximately 2 years to collect and treat the ground water within the
     maximum target zone, which is considered to be the maximum possible
     extent of contamination.  These time frames are based on use of the
     reinjection system design presented in the report.  Reinjection of
     ground water outside the zone of contamination creates a mound of
     ground water which forces ground water toward the collection wells and
     shortens the total time to collect and treat the ground water within
     the target zone.  The actual length of the project will depend upon
     the actual zone of contamination as described under Item 6.  As soon
     as the influent ground water quality meets the criteria, remediation
     will cease.

9.   The Hazard Ranking System (HRS) Score
     At the time the HSTC Site was placed on the NPL, it was appropriately
     scored and the score was adequate for its inclusion on the NPL.  There
     was an official public comment period provided for cooment on the
     listing.  Response actions taken after NPL listing do not result in a
     rescoring of the site.
                                     -3-
                                                                      183/7

-------
10.  Ingestion versus Dermal and Inhalation Exposure of Residents with
     Shallow Irrigation Wells Downgradient of the Site
     It is true that the analysis under the public health evaluation did
     include consideration of the ingestion criterion versus the dermal and
     inhalation criterion.  The ingestion criterion oust be used in a case
     like this where there is a possibility that children or anyone else
     might come into contact with or actually drink water from the
     irrigation system.  There is no way to absolutely preclude this from
     happening; therefore, the more conservative criterion was applied in
     the analysis.

11.  Consideration of Other Sources of Contamination to the Ground Water in
     the Hollingsworth Area
     The objective of this study was to evaluate the HSTC Site as a source
     of contamination and to determine a method to adequately clean up that
     contamination.  It is clear which areas have been contaminated by
     Hollingsworth and only those areas have been included in the
     feasibility study for remediation.

12.  Fouling of the Air Stripping System
     The use of air stripping columns for removal of volatile organics from;
     ground water is a proven technology that is widely being applied in
     this field.  The fact that over time, air stripping columns decrease
     in efficiency of removal of contaminants is a maintenance problem.
     Maintenance costs were included in the feasibility study to cover
     proper monitoring and scheduled maintenance of the system to prevent
     production of effluent which does not meet the cleanup criteria.

     In this system, the-"water will be withdrawn from a depth of
     approximately 60 to 70 feet.  This is the lower sand zone, a zone
     above the production zone or the limestone aquifer.  The total
     dissolved solids level in this zone is somewhat less than the
     production zone of the aquifer, therefore the tendency for fouling is
     diminished.  Further, there are a number of techniques that can be
     used to reduce the fouling problem in both the air stripping system
                                     -4-
                                                                      183/1

-------
     and recharge system.  One of these methods includes the introduction
     of low concentrations of hydrogen peroxide into the influent.  The
     hydrogen peroxide keeps iron in solution through the air stripping
     column and reduces fouling; it also helps to keep iron in solution
     throughout reintroduction via the recharge system.  The peroxide
     itself readily decomposes to water and oxygen and it does not
     represent a contaminant.  The use of hydrogen peroxide has the added
     benefit of actually cleaning the air stripping system due to creation
     of bubbles on the surface of the columns which effectively scrub the
     air stripping columns.  Hydrogen peroxide also prevents or reduces the
     growth of biological organisms.  There are. other techniques to reduce
     fouling that can be applied depending upon the specific water quality
     characteristics of the water in the zone to be treated.  These
     determinations will be made during final design.

13.  Intrusion of Contaminants from Offsite
     The ground water collection, treatment and recharge system designed
     for the HSTC Site will minimize the possibility that contaminants from.
     offsite will be collected by the system.  The configuration of the
     recharge wells is designed to create a ground water barrier in the
     shallow zone.  Reinjection of the water will create a mound of ground
     water or a ground water divide, which will prevent water from moving
     outside of the target zone into the recovery system.  Water may still
     pass under the site in the production zone; however, the
     concentrations of contaminants in the production zone have been
     documented to be very low due to the high volume of water and dilution
     and further, this zone has not been slated for treatment.  The
     recharge system is not expected to result in the spread of
     contaminants offsite.  At the time the recharge wells are installed at
     each of the 10 locations, water samples will be collected and
     analyzed.  If contamination is present at these wells, the wells will
     be relocated and the information will be passed along to the
     appropriate local agency for investigation into the source of
     contamination.
                                     -5-
                                                                      183/7

-------
14.  Accidental Spills within the Zone of Cleanup
     To date there is no evidence that spills have occurred in the vicinity
     of the HSTC Site that may be influencing the presence of contaminants
     at that site.  Therefore, there is no reasonable cause for concern
     that spills will occur in the future which may impact remediation of
     the site.  Obviously, there is no way to police this entire area
     against accidential or intentional spills; however, the fact that this
     has not been a problem in the past indicates that in all likelihood it
     will not be a problem in the future.

15.  Leaking in the Ground Water Recharge System
     The water that will be transported from the treatment system to the
     recharge wells will be of drinking water quality.  Therefore, if a
     leak should occur in the distribution system itself, no contamination
     or violation should occur.  Damage due to the presence of water alone
     may be a consideration; however, over the short time period of this
     project, properly laid piping should not present a major problem of
     leaking, and further, maintenance costs have been included to cover
     periodic checking of the distribution system.

16.  The Size of the Ground Water Treatment System
     The air stripping system designed for this project has been optimized
     rather than over built, to minimize the length of time to recover and
     treat contaminated ground water at the site, thereby minimizing the
     operatipn and maintenance cost and the overall project costs.

17.  The Ability of the Ground Water Recovery System to Recover
     Contaminants
     Recovery of ground* water contaminated with volatile organics, such as
     the trichloroethene found on the HSTC Site, has been successfully
     demonstrated at several sites across the country and is considered to
     be an effective technology for collection of these contaminants.  The
     fact that trichloroethene is relatively insoluble and heavier than
     water does not prevent it from being recovered in the ground water.
                                     -6-
                                                                      183/7

-------
     The extraction wells have been located in the areas and at depths
     where the highest concentrations of contaminants have been found to
     optimize contaminant recovery.
                                            t
18.  Financial Conditon of the Hollinqsworth Solderless Terminal Company
     While the National Contingency Plan requires that EPA choose a cost
     effective site remedy, the financial condition of a potentially
     responsible party is not an element of this determination.  CERCLA was
     adopted with recognition that responsible parties might not be able to
     afford the appropriate site remedy.

19.  Sampling and Test Data
     While all available data was used in evaluating this site, the most
     recent data depicting current site conditions was used to evaluate
     site remedies, rather than data that depicted conditions at some time
     in the past.  An analysis of the results of the most recent episode of
     ground water sampling where samples were split between EPA and
     Enviropact showed that the results from both labs were consistent with
     the exception of the values for vinyl chloride.  Enviropact failed to
     detect vinyl chloride in the samples, whereas the contract lab
     detected vinyl chloride at estimated concentrations ranging from 200
     to 5,000 parts per billion.  Otherwise, the data for each of the wells
     were very similar and within reasonable variation between two
     laboratories.  Both laboratories found trichloroethene and
     dichloroethene in the intermediate depth well at the upgradient
     location.  The probability that this is from offsite contamination is
     extremely low since contaminants deposited onsite have not migrated
     very far downgradient of the site.  There are no known nearby sources
     of contaminants other than the discharge to the Gaidry property and
     the area between the two former Hollingsworth buildings (north plant).
     Because the ground water gradient at this site is extremely flat,
     dispersion may partially account for the fact that well 17 is
     contaminated.  The ground water gradient varies by only 1/10 of an
     inch in this area.
                                     -7-
                                                                      183/7

-------
     Since Enviropact did not measure toluene and xylene, it is impossible
     to compare the two data sets with regard to these contaminants.  There
     is no known source for these contaminants at the HSTC Site and
     therefore, it it likely that they are contaminants of the regional
     aquifer, probably from gasoline spills.  These contaminants would be
     removed by air stripping, along with the volatile organic contaminants
     from the site.  Therefore, they would not be a source of offsite
     contamination.  The presence of other contaminants that may or may not
     be attributable to this site does not preclude the need to address
     contaminants that can be unequivocally linked to the HSTC Site.

20.  Absence of Contaminants in the Production Zone of the Aquifer
     The test well and monitor well onsite are completed into the
     production zone of the aquifer.  This zone is extremely permeable and
     large volumes of water move through the site in this zone.
     Contaminants moving vertically into this zone would be greatly
     diluted.  Thus, it is no surprise that contaminant concentrations are
     below detection limits.  A similar explanation could be expected to
     apply to wells at the 100-foot depth.  However, these results could
     not be directly compared to the shallower test results where
     contaminants are known to be moving through the sand zone.  The fact
     that contaminants are below detection limits in the deeper zones does
     not eliminate the responsibility to clean up the contamination of the
     shallow zone, nor is it conclusive unless it is to indicate that once
     contaminants migrate into the production zone they are diluted and
     transported offsite.

21.  Monitoring the Ground Water Treatment System
     Once the air stripping unit has been properly set up and set into
     operation, monitoring of the treated ground water will occur on a
     weekly basis.  This type of treatment unit is considered very reliable
     and hence, there is no justification for continuous monitoring.  The
     only way the system can fail (given proper setup and maintenance) is
     if the pump goes out.  In this case, an alarm will go off and the
                                     —8—
                                                                      183/1

-------
     system will automatically shut down.  Therefore, untreated ground
     water will not be recharged.  Time for proper maintenance has been
     included in the cost estimate.
                                            /
22.  Application of In Situ Aeration
     In situ aeration was not considered in the feasibility study.because
     it does not meet the criterion of being a proven engineering
     technology.  The effects and effectiveness would be difficult to
     control and monitor.  Further, this technique could potentially
     enhance offsite migration of contaminants.

23.  Disruption of Hollingsworth's Tenants During Site Remediation
     Although this may be a legitmate concern, it ffcauld be noted that
     during December 1984, 11 soil borings were performed on and in the
     immediate vicinity of the Hollingsworth property without any
     disruption of the tenants.  In February 1985, monitor wells were
     installed around the site, also with no disruption of the tenants or
     their normal activities.  The remediation work can be scheduled and
     conducted in a manner to minimize any inconveniences.

24.  Delisting the Site Following Remediation
     Some comments have raised the issue of when EPA will delete a site
     from the NFL.  In general, a site will be removed from the NPL when
     the site remedy has been implemented and information confirms that it
     is performing as anticipated.

25.  NCP Requirements and CERCLA Program Goals
     Several comments were received relative to the National Contingency
     Plan (NCP) and whether the remedy proposed was consistent with it.
     One issue was that"there are no drinking water wells in the path of
     contaminants, thus no action was appropriate.  Several factors combine
     to demand rejection of the no-action scenario,  the aquifer is the
     sole source of drinking water for the area.  State standards are
     violated because of the contamination from the site.  As a natural
                                     -9-
                                                                      183/7

-------
resource, the aquifer is harmed.  Water users are at risk, not only
those users who are in the computer simulated path of contamination,
but others as well.  The computer simulation does not guarantee that
contamination has not nor will not enter the Prospect Lake Well Field
and thus be supplied to the public.  Private wells for irrigation, or
for drinking water, cannot be completely precluded from the area.
Even forceful regulation is not 100 percent effective.  There exist no
effective natural or man-made barriers to contaminant migration.
There exists no alternative source of potable water at this time or in
the reasonable future except this aquifer.  The contaminants detected
include known carcinogens.  A remedy is available which is safe,
effective, technically feasible and reliable, and will provide reduced
risks to public health and the environment.

The recommended technology has been applied at similar sites.  Dade
County plans a much larger air-stripping system for their water supply
with confidence in its anticipated benefits.  The environmental
effects are far less than the benefits and are controllable.  The cost
is well within the range of other alternatives that provide less
benefits to public health, welfare and the environment.  The NCP
(Section 300.68(j)) describes "The appropriate extent of remedy shall
be determined by the lead Agency's selection of the remedial
alternative which the Agency determines is cost effective (i.e., the
lowest cost alternative that is technologically feasible and reliable
and which effectively mitigates and minimizes damage to and provides
adequate•protection of public health, welfare, or the environment).
                               -10-
                                                                 183/r

-------