Super fund Proposed Plan
U.S. Environmental Protection Agency, Region 2
         Peninsula Boulevard Groundwater Contamination Superfund site
                                   Nassau County, New York
  July 2011
EPA ANNOUNCES PROPOSED PLAN

This Proposed Plan describes the remedial alternatives
considered  for  the  contaminated  groundwater at the
Peninsula   Boulevard   Groundwater   Contamination
Superfund site and identifies the preferred  remedy with
the rationale for this preference.  This Proposed Plan was
developed by the U.S. Environmental Protection Agency
(EPA)  in  consultation  with  the  New  York   State
Department of Environmental Conservation (NYSDEC).
EPA is issuing this Proposed Plan as part  of its public
participation responsibilities under Section  117(a) of the
Comprehensive       Environmental        Response,
Compensation, and Liability Act (CERCLA) of 1980, as
amended, and Sections 300.430(f) and 300.435(c) of the
National  Oil  and  Hazardous  Substances  Pollution
Contingency Plan (NCP). The nature and  extent of the
contamination at the site and the remedial alternatives
summarized in this Proposed Plan are described in the
June 2011  Remedial  Investigation (RI)  Report and
Feasibility  Study (FS) Report, respectively. EPA and
NYSDEC   encourage  the  public to  review  these
documents to gain a more comprehensive understanding
of the site and the Superfund activities that have  been
conducted.

This Proposed Plan is being provided as a supplement to
the above-noted documents to inform the public of EPA
and NYSDEC's preferred remedy and to solicit public
comments pertaining to all of the remedial alternatives
evaluated, including the preferred alternative.  EPA and
NYSDEC's preferred alternative involves the extraction
and on-site treatment of contaminated groundwater. The
treated groundwater effluent  would  be  disposed by
discharge to a waste-water treatment plant, surface water
or reinjection to groundwater.

The  remedy described in this Proposed  Plan is the
preferred remedy for the site. Changes to the preferred
alternative or a change from the preferred alternative to
another alternative may be made if public comments or
additional data indicate that such a change will result in
a more appropriate remedial action. The final  decision
regarding the  selected remedy will be made after  EPA
has taken into consideration all  public comments.   EPA
is  soliciting public comment on all of the alternatives
considered  in  the  Proposed Plan and  in  the  detailed
analysis section of the FS report, since EPA and NYSDEC
may select a remedy other than the preferred alternative.
           MARK YOUR CALENDAR

  PUBLIC COMMENT PERIOD:
  July 28, 2011 -August 27, 2011
  EPA will accept written  comments on the Proposed Plan
  during the public comment period.

  PUBLIC MEETING: August 3, 2011 at 7:00 pm
  EPA will hold a public  meeting to  explain the Proposed
  Plan and all of the alternatives presented in the Feasibility
  Study. Oral and written comments will also be accepted at
  the  meeting. The meeting will be held at the Village of
  Hewlett High School, 60 Everit Avenue, Hewlett, NY.
 COMMUNITY ROLE IN SELECTION PROCESS

 EPA and NYSDEC rely on public input to ensure that the
 concerns of the community are considered in selecting an
 effective remedy for each Superfund site.  To this end, the
 RI and FS reports and this Proposed Plan have been made
 available to the public for a public comment period which
 begins on July 28,  2011 and  concludes on August 27,
 2011.

 A public meeting will be held during the public comment
 period at the Hewlett High School on August  3, 2011 at
 7:00 p.m. to present the conclusions  of the  RI/FS, to
 elaborate further  on  the reasons for recommending the
 preferred alternative, and to receive public comments.
         INFORMATION REPOSITORIES

  Copies of the Proposed Plan and supporting
  documentation are available at the following information
  repositories:

  Hewlett-Woodmere Public Library
  1125 Broadway
  Hewlett, New York 11557-0903
  Telephone: (516)374-1967
  Hours of operation:
  Mon-Thurs 9 am - 9 pm
  Fri 9-6, Sat 9 am - 5 pm, Sun 12:30 pm - 5 pm

  USEPA-Region II
  Superfund Records Center
  290 Broadway, 18th Floor
  New York, New York 10007-1866
  (212)637-4308

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Comments  received at the  public meeting, as well  as
written   comments,   will  be   documented   in  the
Responsiveness  Summary  Section of  the  Record  of
Decision (ROD), the  document  which formalizes the
selection of the remedy.

Written comments  on the Proposed  Plan should  be
addressed to:
                   Gloria M. Sosa
             Remedial Project Manager
        Western New York Remediation Section
         U.S. Environmental Protection Agency
              290 Broadway, 20th Floor
           New  York, New York 10007-1866
              telephone: (212) 637-4283
                fax:  (212) 637-3966
             e-mail: sosa.gloriaigiepa.gov

SCOPE AND ROLE OF ACTION

The primary objectives of this action are to remediate the
groundwater contamination, to minimize the migration
of contaminants, and to minimize any  potential future
health and  environmental impacts.  This Proposed Plan
addresses  groundwater   contamination,   designated
Operable Unit 1  (OU  1) at the site.  EPA is  currently
conducting an RI to identify and  delineate the potential
source(s)    of    the    tetrachloroethylene    (PCE)
contamination, designated Operable Unit 2 (OU 2).  A
final remedy to address the source contamination will  be
presented in  a  future  Proposed  Plan  and Record  of
Decision.

SITE BACKGROUND

Site Description

The   Peninsula   Boulevard  Groundwater   Plume
Superfund Site (the Site) consists  of the area within and
around a groundwater plume located in the Village of
Hewlett,  Town of Hempstead, Nassau County, New
York. John F. Kennedy International Airport is located
approximately three miles to the  west of the  Site.  A
Site location map is provided as Figure 1.

The  area  consists of  a  mix  of commercial and
residential  properties,  with   the  majority  of  the
commercial properties being located along Mill  Road,
Peninsula Boulevard, Broadway,  and West Broadway.
Woodmere Middle School is located along the western
site boundary.  Portions of Motts Creek, Doxey Brook
Drain, and an unnamed tributary leading to Motts Creek
are located  within the Site.

The residences in the area of the Site are serviced by the
Long Island American Water Company  (LIAWC).  The
LIAWC operates a well field approximately 1000  feet
north of the Site. The water delivered to these residents is
a blend of water from several well fields.  Since 1991,
LIAWC has  been treating groundwater pumped from this
well field with an air stripper prior to distribution.  Based
on a records review of water supply  wells in the area,
private wells are not  utilized for drinking water  in the
area.

Site History

A series of investigations and removal  actions from 1991
to 1999 on  behalf of the  owner of the former  Grove
Cleaners   and  the NYSDEC  revealed an  extensive
groundwater  contaminant plume extending both to the
north  and  south  of  Peninsula  Boulevard,  primarily
consisting of the chlorinated  volatile organic compound
(CVOC) PCE.

The  investigation revealed that operations at the former
Grove  Cleaners, located at 1274 Peninsula Boulevard,
from 1987 to 1992 resulted in the disposal of hazardous
wastes, including the volatile organic compounds (VOCs)
PCE and trichloroethylene (TCE) to the environment.  In
March 1991, the Nassau County  Department of Health
(NCDH) cited Grove Cleaners for discharging hazardous
waste into on-site dry wells.  PCE was detected in soil and
sludge samples collected at the Grove Cleaners site, and in
other media  at and near the property.  The results of the
investigation suggested the potential for additional source
areas  other  than   the former  Grove  Cleaners  site.
Following  the  implementation  of  interim  remedial
measures,  which consisted  of the  removal  of impacted
soils related to  solvent discharge to a  dry  well, a No
Further Action  remedy was  selected by NYSDEC in
March 2003  for the former Grove Cleaners site.

On March 7, 2004,  EPA proposed inclusion of the Site on
the National Priorities List (NPL) and  on July 22, 2004,
EPA placed the Site on the NPL.

EPA conducted an RI at the  Site from 2005 through 2010.
Environmental  sampling of groundwater, surface  water,
soil and sediment was  performed and  a  Data Evaluation
Report (DER) presenting the results of the environmental
sampling was prepared in October 2008. Supplemental RI
work was  conducted at the  Site in 2010 to  address data
gaps including  hydrogeological sampling and analyses,
and to develop a baseline human  health risk assessment
(HHRA) and screening-level  ecological risk assessment
(SLERA).  A DER Addendum was issued in December
2010 presenting the results of this sampling.  A RI Report
was released in June 2011.

The  RI identified groundwater contaminated with PCE,
PCE breakdown products and low levels of other VOCs.

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The source of the PCE groundwater contamination has
not yet been identified.

Site Hydrogeology

The Upper Glacial  Aquifer  (UGA) underlies the Site.
Groundwater flow  in  the UGA  is dominated by  a
groundwater  divide  located approximately  2000  feet
south of Peninsula Boulevard, along a low ridge trending
southwest to northeast. North of the divide, groundwater
flow is both north and west, depending  upon  depth.
South of the divide, groundwater flow within the UGA
southward toward Macy Channel.

North of the Site, the UGA overlies the Jameco Aquifer.
In this  area  of Long  Island,  the Jameco Aquifer is
limited in extent, but is an important water-bearing zone
because of its high hydraulic conductivity  on the order
of 200 feet per day.  The  LIAWC Plant #5 Well Field
adjacent  to the Site utilizes the Jameco as its source
aquifer  and  does  not  utilize the  UGA  for  water
production.   Given the similar hydraulic properties of
the UGA  and  Jameco,  there  is the potential  for
significant hydraulic connection between the two units.
However, data obtained as a result of the supplemental
RI activities indicate that  the Gardiners Clay acts as a
confining unit in the localized area of the  Site and the
LIAWC well field.

The  inter-bedded  nature  of sediments in  the  UGA
suggests  significant vertical and horizontal variability in
hydraulic conductivity values.  The "20-foot clay"  is a
discontinuous, semi-confining layer which separates the
UGA into an upper and lower zone in some areas of the
Site.

The depth to groundwater within the unconfined portion
of the  UGA  ranges  from approximately 3 to 15  feet
below ground surface (bgs), while ranging from 6 to 17
feet  bgs  in  the  semi-confined   portion  of aquifer.
Saturated thickness  of the unconfined UGA above the
"20-foot clay" layer ranges from 10 to 30 feet.  Saturated
thickness of the deeper portion of the UGA below the
"20-foot  clay", including the pressure head component
caused   by    the   semi-confined    conditions,   is
approximately 55 to 65 feet.

RESULTS OF THE REMEDIAL INVESTIGATION

The results of the RI indicate that the shallow and deep
portions  of the  UGA have  been impacted by  CVOC
contamination.  The shallow UGA groundwater (0 to 30
feet bgs) PCE plume is approximately  3,500 feet long,
oriented in a north-south direction.  South  of Peninsula
Boulevard  (upgradient),  the  plume  is approximately
1,000  feet wide and  north of  Peninsula  Boulevard
(downgradient) the plume is approximately 400 feet wide.
(See Figures 2 & 3)

The  deep UGA (40 to 75 feet bgs) groundwater  plume is
approximately 1,110 feet  long, oriented  in a northeast-
southwest direction.

Groundwater

EPA conducted a Membrane  Interface Probe (MIP)
investigation and Hydropunch® sampling at the Site in
2006 and 2007.  A  total  of 160 groundwater  samples
were collected from 61 locations.  The  results of this
effort  assisted  EPA  in  selecting  locations  for  the
installation of groundwater-monitoring wells.    Twenty-
six monitoring wells were installed at the Site and several
rounds of sampling were conducted in 2007, 2008, 2010,
and  2011.   Analytical results for these  samples were
compared to the EPA and New York State Department of
Health (NYSDOH) promulgated  health-based  protective
Maximum  Contaminant   Levels  (MCLs),  which  are
enforceable   standards  for  various  drinking  water
contaminants.

Groundwater   contamination    exceeding    applicable
drinking water standards has been shown  to exist within
the Site plume area, at highly elevated concentrations in
some areas.  Chlorinated VOCs, PCE in particular, were
identified as the plume-related contaminants of  concern
for the shallow and deep portions of the UGA at  the Site.
Seven VOCs were detected at concentrations  exceeding
applicable criteria.   Specifically,  PCE was detected at
levels up to  30,000 micrograms per liter (ug/1) and TCE,
at concentrations up to 10,000 ug/1.

The   RI  groundwater  data  indicate   that   the  Site
contaminant plume in the deep  portion of  the  UGA,
dominated by PCE,  appears  stable and centered  in  the
south-central portion of the Site.

Information obtained from  LIAWC and the results of EPA
sampling at  new production wells on LIAWC  Plant #5
property in October 2010 indicate that the Plant #5 Well
Field has contamination similar to that found  in the Site
plume and,  therefore,  may have  been impacted by  the
contamination from the Site.

An engineering control (air stripper) is maintained at the
Plant #5 Well Field by LIAWC.  The treated groundwater
is tested and monitored by LIAWC in accordance with
New York    State  and   Nassau   County   rules  and
regulations.  No MCL exceedances of chlorinated VOCs
in water distributed to the general public have been
identified during the RI.

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The  results  of the  RI indicate that the potential for
natural  attenuation  of chlorinated  compounds varies
across the Site.   PCE  daughter  products  were  not
consistently  detected in the same groundwater wells as
PCE. Given site-specific conditions, natural attenuation
of CVOCs does not appear to be a dominant process in
the subsurface.

Surface Water, Soils and Sediments

The RI included sampling of soil at depths of 0-10 feet
bgs.  Surface soil (0-2 ft bgs) samples were collected at
locations along the long axis (N-S)  of the plume and in
areas of elevated exposure potential.   Subsurface soil
sample locations were co-located with  the Membrane-
Interface Probe (MIP)  and Hydropunch® groundwater
sampling locations.

Surface water and  sediment samples  were collected
from  the  Doxey Brook Drain, Motts  Creek and the
unnamed  waterway.  There were  no  exceedances  of
applicable criteria  for plume-related  compounds  in
surface  water or sediment samples.  No VOCs were
detected  in  surface soil and  no plume-related VOCs
exceeded screening criteria in subsurface soil.

Vapor Intrusion

EPA is investigating the soil vapor  intrusion pathway at
the Site.   VOC  vapors  released   from contaminated
groundwater  and/or soil   have  the potential to move
through the  soil and seep  through cracks in basements,
foundations, sewer lines and other openings.

EPA  conducted vapor  intrusion  sampling  at fifteen
residences at the Site. EPA drilled through the sub-slabs
in the basements and installed ports in order to sample
the soil vapor under these residences. Sampling devices
called Summa canisters were attached to these ports to
collect air at a slow flow rate over a twenty-four hour
period.   Summa canisters were  also  placed  outside
several residences to determine if there were any outdoor
sources  that may  impact indoor   air.   The  Summa
canisters were then collected and sent to a laboratory for
analyses.

The results of the analyses indicated that one residence
had concentrations of VOCs at or above EPA Region 2
screening levels in sub   slab and indoor air.   EPA
installed a  sub-slab  depressurization  system  at  this
residence  in 2009 to mitigate the impacts of soil vapor
intrusion by  reducing or eliminating vapor entry into the
building.  EPA sampled indoor air in this residence in
2010 and VOCs were not detected in indoor air.
In addition to sampling residences for soil vapor intrusion,
EPA  sampled the North  Woodmere Middle School in
2004  using  a mobile laboratory to  analyze the results.
PCE was not detected in the basement,  the area through
which vapors would enter the building if there were vapor
intrusion impact from the groundwater plume (there is no
slab in  the  basement, but a dirt floor).  No  PCE was
detected in the classrooms or the auditorium.  PCE was
detected in trace levels in the art room and in the drains in
a bathroom  (possibly from  art  supplies and  personal
hygiene products such  as hair  gel).  The  trace levels
detected (0.15 - 0.35 parts per billion or ppb) do not pose
any health concern.

EPA will continue to investigate the soil vapor intrusion
pathway at the Site.

Source Investigation

The source of the PCE  contamination was not identified
during the OU 1 RI.  Groundwater-plume characteristics
(areal  extent  and  relative  concentrations)  appear  to
indicate a  potential source area at in the area along West
Broadway.   The wider width of the  plume  south  of
Peninsula  Boulevard may  be the result of comingling of
contaminant plumes from additional upgradient source
areas, radial groundwater flow induced from pumping, or
the  flat groundwater surface. EPA is currently conducting
an  OU  2  RI in order to  delineate  the  source(s) of the
groundwater contamination.

RISK SUMMARY

As  part of  the  RI, EPA conducted  a baseline  risk
assessment to estimate the current and  future  effects of
contaminants on human health and the  environment.  A
baseline risk assessment is an analysis  of the  potential
adverse  human health and ecological effects of releases of
hazardous substances from a site in the absence of  any
actions or  controls to mitigate such releases, under current
and future land, groundwater, surface water and sediment
uses.  The baseline  risk assessment includes a  Human-
Health Risk Assessment (HHRA) and an ecological risk
assessment.

The cancer risk and non-cancer health hazard estimates in
the  HHRA  are  based on  current  reasonable maximum
exposure scenarios  and  were developed by taking into
account various health  protective  estimates about  the
frequency  and duration of an  individual's  exposure to
chemicals  selected  as  chemicals  of potential  concern
(COPCs),  as well as the toxicity of these contaminants.
Cancer risks and non-cancer health hazard indexes (His)
are  summarized below (please see the text box on page 6
for an explanation of these terms).

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The  Site is currently a residential  neighborhood,  with
some nearby properties designated as mixed commercial.
Future land use is expected to remain the same.  The
baseline risk assessment began by  selecting COPCs in
the various  media that would be representative of Site
risks. The media evaluated as part  of the human health
risk  assessment included soil (0-10 feet),  groundwater,
and  surface water and sediment from the Doxy Brook
Drain,   Motts  Creek  and the  unnamed  waterway.
Groundwater at the Site is designated by NYSDEC as a
potable water supply.  The chemicals of concern (COCs)
for the Site are cis-l,2-dichloroethylene (cis-l,2-DCE),
PCE, TCE, and vinyl chloride  (VC) for groundwater
pathways.

The  baseline risk assessment evaluated  health  effects
that  could result from  exposure to  contaminated media
though  use of  groundwater  for potable  purposes
(including  inhalation  of vapors  in  the bathroom  after
showering),  direct exposure  to  groundwater  in  an
excavation  trench,  wading in Site waterways, direct
contact exposure to surface (0-2 feet) and subsurface soil
(2-10 feet),  and inhalation of vapors from surface soils.
Based on the current zoning and anticipated future use,
the risk assessment  focused on  a  variety of possible
receptors, including current and future recreational users,
future residents, future commercial workers and future
construction workers.   However,  consistent  with the
anticipated  future  use  of the  Site,  the  receptors  most
likely to be in contact with media impacted by  site-
related contamination [e.g., groundwater] were primarily
considered  when weighing possible  remedies for the
Site.

These include  the future residents, future commercial
workers and future construction workers.   A complete
discussion  of the exposure pathways and estimates  of
risk can be found in the Human Health Risk Assessment
for the Site in the information repository.

A screening-level  ecological  risk assessment (SLERA)
was  conducted to  evaluate the potential  for ecological
effects from exposure to surface soil, surface water and
sediment.    Surface soil,  surface water,  and  sediment
concentrations  were  compared to ecological screening
values as an indicator of the potential for adverse effects
to ecological receptors.   A complete summary of the
methodology utilized can be found  in the Screening
Level Ecological Risk Assessment  for the Site in the
information repository.

The  results  of the RI indicated that sediments  and  soils
were not contaminated with site-related contaminants;
therefore, no risks were calculated  for exposure to Site
sediments or soils.  Exposure to surface waters did not
pose an unacceptable cancer risk or non-cancer hazard.
EPA is currently conducting an ongoing investigation of
vapor intrusion into structures within the area that could
be potentially affected by the groundwater contamination
plume.   To  date,  one  home  has received a  sub-slab
depressurization system  to mitigate  vapors entering the
home.   If results of current or future sampling  of other
homes indicate the presence of site-related vapors above
protective levels, EPA would expect to implement similar
measures.

Human Health Risk Assessment

EPA's statistical analysis of ground water sampling data
found that the average exposure concentration of cis-1,2-
DCE, PCE, TCE, and VC  in the groundwater were  710
ug/1, 11,000 ug/1, 920 ug/1,  and 59 ug/1,  respectively.  All
are in excess  of EPA's Safe Drinking Water Act MCLs of
70  ug/1, 5 ug/1, 5 ug/1,  and  2  ug/1, respectively; these
concentrations also  exceed the NYSDOH MCLs,  which
are 5 ug/1 for cis-l,2-DCE,  PCE, and TCE,  and 2 ug/1 for
VC.  These concentrations  are associated with an excess
lifetime cancer risk  2  x 10"1 for the future adult and child
resident and  2 x 10"2 for the future  commercial worker.
The calculated non-carcinogenic hazard quotients  (HQs)
are: future adult resident HQ=300, future  child resident
HQ=600 and  future commercial worker HQ=50.

These cancer risks and non-cancer health hazards indicate
that  there  is significant  potential  risk  to potentially
exposed populations from direct exposure to groundwater
or and groundwater  vapors. For these receptors, exposure
to groundwater results in either an excess lifetime cancer
risk that exceeds EPA's target risk range of 10"4 to 10"6 or
an HI  above the acceptable level of  1, or both.   The
chemicals   in  groundwater    that   contribute  most
significantly to the cancer risk and non-cancer hazard are
cis-l,2-DCE,  PCE, TCE,  and VC.

Ecological Risk Assessment

The  SLERA focused  on potential exposure  to plume-
related   contaminants  (i.e.,   CVOCs).  The  CVOCs
identified in  the surface water, interstitial water and/or
sediments  include  cis-DCE;  methylene chloride; PCE;
TCE, and VC. While other  contaminants were detected in
environmental samples, these other compounds and their
concentrations may  be indicative of the urbanized nature
of  the  area  and   are   not   considered  site-specific
contaminants.

The ecologic receptors evaluated in  the risk assessment
included  benthic   macroinvertebrates   in   the  aquatic
environment  and  birds  and   small  mammals  in  the
terrestrial environment.   Birds that were observed using
the Site included mallard duck,  American robin, red-
winged blackbird, common  grackle, double-crested

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WHAT IS RISK AND HOW IS IT CALCULATED?

Human Health Risk Assessment:  A Superfund baseline human
health risk assessment is an analysis of the  potential adverse
health effects caused by hazardous substance releases from  a
site in the absence of any actions to control  or mitigate these
under current- and future-land  uses.   A four-step process is
utilized  for  assessing site-related  human  health  risks  for
reasonable maximum exposure scenarios.

Hazard  Identification:  In this step,  the  chemicals  of  potential
concern   (COPCs)  at  the  site in  various  media  (i.e.,  soil,
groundwater, surface water, and air) are identified based on such
factors  as  toxicity,  frequency  of occurrence,  and  fate and
transport of the contaminants in  the environment, concentrations
of the contaminants in  specific media, mobility, persistence, and
bioaccumulation.

Exposure Assessment: In  this step,  the  different  exposure
pathways through  which   people  might be  exposed  to  the
contaminants in air, water, soil, etc. identified in the previous step
are  evaluated.    Examples of  exposure  pathways  include
incidental ingestion of and  dermal contact with  contaminated  soil
and  ingestion  of and dermal  contact  with  contaminated
groundwater.   Factors relating to  the  exposure assessment
include, but are not limited to, the concentrations in specific media
that people  might be exposed to and the  frequency and duration
of that exposure.  Using these factors, a "reasonable maximum
exposure" scenario, which  portrays the highest level of human
exposure that could  reasonably  be expected  to occur,  is
calculated.

Toxicity  Assessment:  In this step, the types of  adverse health
effects associated  with chemical exposures, and the relationship
between magnitude of exposure and severity of adverse effects
are determined.   Potential  health effects are  chemical-specific
and may include the risk of developing cancer over a lifetime or
other non-cancer health hazards, such as changes in the normal
functions of  organs  within the  body  (e.g.,  changes in  the
effectiveness  of the immune system).   Some  chemicals  are
capable of causing both cancer and non-cancer health hazards.

Risk Characterization:  This step  summarizes  and combines
outputs of the exposure and toxicity  assessments to provide  a
quantitative assessment of  site  risks for all COPCs. Exposures
are evaluated based on the potential risk of developing cancer
and the potential for non-cancer  health hazards. The likelihood of
an individual developing cancer is expressed as a probability.  For
example, a 10"4 cancer risk means a "one-in-ten-thousand excess
cancer risk"; or one additional cancer may be seen in a population
of 10,000 people  as a result of exposure to site contaminants
under the conditions  identified  in the  Exposure Assessment.
Current Superfund regulations for exposures identify the range for
determining whether remedial action is necessary as an individual
excess lifetime cancer risk of  10"4 to 10"6,  corresponding to  a
one-in-ten-thousand to  a one-in-a-million excess cancer risk.  For
non-cancer  health effects,  a "hazard index" (HI) is calculated.
The  key concept  for  a non-cancer HI  is that a "threshold"
(measured as an HI of less than  or equal to 1) exists below which
non-cancer  health  hazards are not expected to occur.  The goal
of protection is 10"6 for cancer risk and an HI of 1 for a non-cancer
health hazard.  Chemicals that exceed a 10"4 cancer risk or an HI
of 1 are typically those  that will require remedial action at the  site
and are referred to as Chemicals of Concern  or COCs in the final
remedial decision or Record of Decision.
cormorant,  blue  jay,  mourning  dove,  white-throated
sparrow,  green-winged  teal,  black-capped  chickadee,
tufted titmouse, northern flicker,  song sparrow,  Canada
goose,  northern  cardinal,  house  sparrow,  house finch,
European  starling,  and  killdeer.   Mammals that were
observed included Norway rat, raccoon and gray squirrel.
Potential  risks were  not quantified for  each observed
species, however, the risk for each category of species was
estimated  using  a  receptor species  (e.g.,  raccoon)  or
species  groups  (e.g.,  benthic  macroinvertebrates)  as
surrogates  to represent the  various  components  of the
ecological community.

The ecological receptors were  assumed to be exposed to
CVOCs   in  surface  waters,  interstitial  waters  and
sediments.  However, it was assumed that the ecological
receptors would not be exposed directly to groundwater
resources.  Additionally,  it  should be noted that VOCs
were not detected in surface soil samples.  Therefore, it is
assumed that there  was  no contamination of these soils
from the  groundwater plume by the  contaminants  of
concern.

The  SLERA  analyses included  the comparison  of the
maximum concentrations of the contaminants of potential
concern   with   the   most   appropriate,   conservative
ecological  screening values  that were identified for these
compounds  for  each of  the  media  of interest.  The
comparison  of the  maximum concentrations  of each
contaminant detected  in the  surface  water, interstitial
water, sediment,  and surface soil with  the ecological
screening value(s) for each media medium did not reveal
any contaminants in excess of these  screening values.
Additionally,  none  of the  contaminants  of interest  are
known to bioconcentrate, biomagnify, or bioaccumulate.

Based on  the  results of the  SLERA,  concentrations  of
contaminants detected in surface water, interstitial water,
sediment and surface soil at the Site are unlikely to pose
any unacceptable risks to aquatic  or terrestrial ecological
receptors at the Site.

Summary of Human Health and  Ecological Risks

The results of the human health risk assessment indicate
that   the   contaminated   groundwater   presents   an
unacceptable   exposure   risk.     The   screening-level
ecological risk assessment indicated that the Site does not
pose any  unacceptable  risks  to  aquatic  or  terrestrial
ecological receptors.

Based upon the results of the RI and the risk assessment,
EPA has determined that actual or threatened releases of
hazardous  substances from the Site, if not addressed by
the preferred remedy or one of the other active measures
considered, may  present a current or potential threat to

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human health and the environment.  It is the EPA's
current  judgment  that  the  Preferred   Alternative
identified  in the Proposed Plan is necessary to protect
public health or welfare or the environment from actual
or threatened releases of hazardous substances into the
environment.

REMEDIAL ACTION OBJECTIVES

Remedial  action objectives (RAOs) are specific goals to
protect  human  health and  the environment.   These
objectives  are  based  on  available  information  and
standards, such as applicable or relevant and appropriate
requirements (ARARs), to-be-considered guidance, and
site-specific risk-based levels.

The   following   remedial   action   objectives   for
contaminated  groundwater  (OU  1) will  address  the
human health risks and environmental concerns:

    •  Restore the impacted aquifer to beneficial use as
       a   source  of drinking  water  by   reducing
       contaminant  levels  to  the federal and  State
       MCLs; and,
    •  Reduce or eliminate the potential for migration
       of contaminants towards the LIAWC.

The  following remedial action  objective for soil vapor
will  address the human health risks and environmental
concerns:

    •  Address existing or  potential  future  exposure
       through  inhalation of  vapors  migrating  from
       contaminated groundwater  into buildings at the
       Site.

SUMMARY OF REMEDIAL ALTERNATIVES

CERCLA §121(b)(l), 42 U.S.C. §9621(b)(l), mandates
that   remedial  actions  must be protective of human
health and the environment,  cost-effective, comply with
ARARS, and utilize permanent  solutions and alternative
treatment    technologies   and   resource    recovery
alternatives to the maximum extent practicable.  Section
121(b)(l)  also  establishes a preference  for  remedial
actions which employ, as a principal element, treatment
to permanently  and significantly  reduce  the volume,
toxicity,   or  mobility  of the  hazardous  substances,
pollutants and contaminants at a site. CERCLA §121(d),
42 U.S.C. §9621(d),  further specifies  that a remedial
action must attain a level  or standard of control of the
hazardous  substances,  pollutants,  and  contaminants,
which at  least attains ARARs  under  federal and state
laws, unless  a  waiver can be justified pursuant to
CERCLA §121(d)(4), 42 U.S.C. §9621(d)(4).
Detailed descriptions  of the remedial alternatives for
addressing the contamination associated with the Site can
be found in the FS report.  The FS report presents four
groundwater alternatives, including a no action alternative.
Based  on  the  screening   analyses  and  evaluations
performed  in the  initial stages  of the   FS,  remedial
alternatives G3  and G5  were screened out of the final
alternatives which are discussed below.

The construction time for each alternative reflects only the
time required to construct or implement the remedy and
does not include the time required to design the remedy,
negotiate  the performance   of  the remedy  with  any
potentially  responsible parties,  or procure contracts for
design and construction.

Common Elements

All of the alternatives, with the exception of the no action
alternative, include monitored natural attenuation (MNA)/
long-term monitoring  to address  areas  of the  plumes
outside of the active remediation areas, and institutional
controls  for  groundwater use  restrictions.  Monitored
natural attenuation is a variety of in-situ processes which,
under   favorable   conditions,   act  without   human
intervention  to  reduce  the mass, toxicity,  mobility,
volume, or concentration of contaminants in groundwater.

Alternative 1:  No Action

The  National Oil  and Hazardous Substance  Pollution
Contingency  Plan (NCP) requires that a "No Action"
alternative be developed as a baseline for comparing other
remedial alternatives.  Under this alternative, there would
be no remedial actions  conducted at the Site to control or
remove groundwater contaminants.  This alternative does
not include monitoring or institutional controls.

Because this  alternative would result in contaminants
remaining above levels that allow for unrestricted use and
unlimited exposure,  CERCLA requires that the  Site be
reviewed at least once every  five years.  If justified by the
review, additional response actions may be implemented.
Capital Cost:
Annual O&M Costs:
Present-Worth Cost:
Construction Time:
           $0
           $0
           $0
Not Applicable
Alternative G2: Enhanced Bioremediation
Capital Cost:
Annual O&M Costs:
Present-Worth Cost:
Construction Time:
    $4,344,000
    $835,000
    $15,830,000
     9-12 months

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This  remedial alternative  consists  of implementing
enhanced bioremediation in the plume area.  Enhanced
bioremediation  is   the   process   of  destruction   of
contaminants by  microorganisms in contaminated soil
and water.  Microrganisms consume organic substances
for nutrients  and energy.   Enhanced bioremediation
involves creating  the  proper conditions  by  injecting
microorganisms   or  nutrients  to  the subsurface  to
accelerate   the   biodegradation  of  the   CVOC
contamination.    The  end  products  include carbon
dioxide,  water and microbial cell mass. Monitoring  of
biogeochemical  parameters  is  used   to  monitor the
effectiveness of remediation.

Enhanced  bioremediation  can  be  implemented  in
different system  configurations.  For the  purposes  of
developing a conceptual  design and  cost  estimate for
comparison with other technologies  in the FS, a transect
configuration was evaluated.   This conceptual design
would require  the installation  of  approximately 146
permanent  injection wells  to remediate contamination in
the shallow UGA plume and  78 permanent  injection
wells to remediate contamination in the deeper UGA.
This conceptual design would require  further evaluation
during the remedial design if chosen to be implemented.
Additional  wells would have to  be  installed to monitor
the progress of the remediation.   This alternative  is
expected to remove the contaminant  mass within eight to
16 years in the shallow  UGA plume remediation area
and  within 25 to 50  years  in  the deep  UGA plume
remediation area.
Alternative G4: In-Well Air Stripping
Capital Cost:
Annual O&M Costs:
Present-Worth Cost:
Construction Time:
$7,730,000
$730,000
$16,710,000
 9-12 months
This remedial alternative includes the installation of in-
well air stripping systems over the plume area.  In-well
air stripping is a physical treatment technology whereby
air is injected into a vertical well that is installed and
screened at two depths in the groundwater.  Pressurized
air is  injected into  the well below the water table,
aerating the water.  The aerated water rises in the  well
and flows out of the system at the upper screen, inducing
localized movement  of groundwater into (and up) the
well as contaminated  groundwater  is drawn into the
system at the lower screen.  VOCs vaporize within the
well at the top of the water table, where the air bubbles
out of water. The contaminated  vapors accumulating in
the wells  are collected via vapor extraction  contained
within the well.  Typically, extracted vapors are treated
(if necessary)  above  grade  and  discharged to the
                    atmosphere.    Vapor  treatment, if required,  generally
                    consists of vapor-phase granular activated carbon (GAC).

                    The partially treated groundwater is never brought to the
                    surface;  it is  forced into the unsaturated zone, and the
                    process  is  repeated  as  water  follows  a  hydraulic
                    circulation pattern that allows  continuous cycling of
                    groundwater.   As groundwater circulates  through the
                    treatment  system  in-situ,  and   vapor  is   extracted,
                    contaminant concentrations are reduced.

                    In-well air  stripping  can  be  implemented in different
                    system configurations.  For the purposes of developing a
                    conceptual design and cost estimate for comparison  with
                    other technologies  in  the FS,  a grid configuration  was
                    evaluated.   This  conceptual  design  would require the
                    installation of approximately 80 permanent air stripping
                    wells to remediate contamination  in the shallow UGA
                    plume and 30 permanent air  stripping wells to remediate
                    contamination in the deeper UGA. This conceptual design
                    would require further evaluation  during the remedial
                    design if chosen to be  implemented.   Additional wells
                    would have to be installed to monitor the progress of the
                    remediation.   This  alternative is expected to remove the
                    contaminant mass within five to 10 years in the shallow
                    UGA plume remediation area and within 10 to 20 years in
                    the deep UGA plume remediation area.

                    Alternative G6:  Groundwater Pump and Treat
                     Capital Cost:
                     Annual O&M Costs:
                     Present-Worth Cost:
                     Construction Time:
                                     $2,997,000
                                     $1,185,000
                                     $21,560,000
                                     6-9 months
This remedial alternative consists  of the  extraction of
groundwater  via pumping  wells and treatment prior to
disposal. Groundwater is pumped to remove contaminant
mass  from  areas  of  the  aquifer  with elevated  PCE
concentrations.   Pumping from downgradient wells  will
provide   hydraulic   control   of   the   contaminated
groundwater  with  lower PCE  concentrations.  For  this
conceptual design, it is estimated that nine groundwater
extraction wells  would be installed in the  shallow  and
deep  UGA.   A  treatment  plant with the capacity of
approximately 350 (gallons per minute) gpm would be
constructed within or nearby the Site to achieve the mass
removal  and  hydraulic  control objectives.   Extracted
groundwater with VOC contamination is typically treated
with either liquid phase GAC or air stripping, or both.  Air
stripper effluent air  stream may  be treated with vapor
phase GAC, if necessary. During the remedial design, a
determination will be made whether to discharge treated
extracted groundwater to a publically  owned treatment
works   (POTW),  surface  water   or  reinjection  to
groundwater.

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In-situ chemical treatment would be utilized to enhance
the groundwater pump and treat remedy, as appropriate.
During the remedial design, a treatability study would be
performed  to  evaluate  the  use  of  in-situ  chemical
treatment, either in-situ chemical oxidation (ISCO) or in-
situ chemical reduction (ISCR).  The results of the study
would be used  to design the in-situ chemical treatment
component  of this  alternative  in  a  manner  that
complements and improves  the  effectiveness  of the
groundwater extraction and treatment component.

ISCO is a process that involves the injection of reactive
chemical oxidants (such as Peroxide, Fenton's Reagent,
Permanganate) into the subsurface for rapid contaminant
destruction.   Oxidation  of organic  compounds using
ISCO  is  rapid and  exothermic  and  results  in the
reduction of  contaminants to primarily  carbon dioxide
and oxygen.  ISCR uses chemical reductants such as
zero-valent iron  (ZVI).    The ZVI donates electrons,
acting as the  reductant  in  a  reaction that removes
chlorine   atoms    from    chlorinated   hydrocarbon
contaminants such as PCE.

In-situ chemical treatments, such as  ISCO  and ISCR
were  evaluated  in the initial stages of the FS, but were
screened out of  the final alternatives  as stand-alone
remedies, because of the difficulty in implementation in
a residential neighborhood, specifically obtaining access
to residential properties.   However,  the use of  in-situ
chemical  treatments targeting  areas  containing high
concentrations of PCE that may reside outside the radius
of influence of the pump within the inferred plume, as
appropriate, in combination with groundwater extraction
could potentially reduce the remediation time frames and
the costs of this alternative.

EVALUATION OF ALTERNATIVES

During the detailed evaluation of remedial alternatives,
each  alternative  is  assessed against  nine  evaluation
criteria, namely, overall protection of human health and
the environment, compliance with applicable or relevant
and appropriate requirements, long-term  effectiveness
and permanence,  reduction  of toxicity,  mobility, or
volume  through  treatment,  short-term  effectiveness,
implementability,   cost,  and  state   and  community
acceptance.   Refer to the table  on the next page for a
description of the evaluation criteria.

This section  of the  Proposed Plan profiles the relative
performance of each alternative against the nine criteria,
noting how  each  compares to the other options under
consideration. A detailed analysis of alternatives can be
found in the FS  Report.
Overall Protection of Human Health and the
Environment

All of the alternatives except Alternative Gl (No Action)
would provide  protection  of  human  health  and  the
environment.  Alternatives  G2,  G4, and  G6 are active
remedies  that address groundwater contamination  and
would restore groundwater  quality over the long term.
Alternatives G2, G4, and G6 would also rely on certain
natural processes to achieve the  cleanup levels  for areas
outside of the treatment zones.

Protectiveness under Alternatives G2 and G4 requires a
combination  of  reducing contaminant concentrations in
groundwater   and  limiting   exposure   to    residual
contaminants  through  maintenance  of  existing,   and
implementation of additional institutional controls, as well
as MNA.

Protectiveness under Alternative  G6 is achieved through
reducing contaminant concentrations  via  extraction  and
treatment  of groundwater.   Alternative G6 also protects
against   the   further   migration   of   contaminated
groundwater, as  the  extraction functions as a hydraulic
plume containment mechanism.

The long-term monitoring program for groundwater  and
vapor  would  monitor the  migration  and  fate  of  the
contaminants and ensure that human health is protected.
Combined   with  MNA,   long-term  monitoring,   and
institutional controls, Alternatives G2, G4, and G6 would
meet the  RAOs.  Alternative Gl  would not meet  the
RAOs

Because Alternative Gl (No Action) is not protective of
human health and the environment, it was eliminated from
consideration under the remaining evaluation criteria.

Compliance   with   Applicable   or   relevant  and
Appropriate Requirements (ARARs)

EPA and  NYSDOH  have promulgated  health-based
protective  MCLs  (40CFR  Part  141, and 10NYCRR,
Chapter 1), which are enforceable standards for various
drinking water contaminants  (chemical-specific ARARs).

The aquifer is classified as Class  GA (6 NYCRR 701.18),
meaning that it is  designated as  a potable water supply.
Although  the groundwater  at the Site  is  not  presently
being utilized as a  potable water  source, achieving MCLs
in the groundwater is an  applicable or  relevant  and
appropriate standard, because area groundwater is a source
of drinking water.  Alternatives G2 and G4 may

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   EVALUATION CRITERIA FOR SUPERFUND
           REMEDIAL ALTERNATIVES

Overall   Protectiveness  of  Human  Health  and  the
Environment evaluates  whether and  how  an  alternative
eliminates, reduces, or controls threats to public  health  and
the environment through institutional controls, engineering
controls, or treatment.

Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) evaluates whether the  alternative
meets federal and  state environmental statutes, regulations,
and other requirements that pertain to the site, or whether a
waiver is justified.

Long-term Effectiveness and Permanence considers the
ability of an alternative to maintain protection of human health
and the environment overtime.

Reduction  of Toxicity, Mobility,  or Volume  (TMV) of
Contaminants   through   Treatment   evaluates    an
alternative's use of treatment to reduce the harmful effects of
principal  contaminants,  their  ability  to  move   in  the
environment, and the amount of contamination present.

Short-term  Effectiveness  considers the length  of time
needed  to implement  an  alternative  and  the risks  the
alternative  poses  to  workers,  the  community, and  the
environment during implementation.

Implementability considers the technical and administrative
feasibility of implementing the  alternative, including factors
such as the relative availability of goods and services.

Cost includes estimated capital and annual operations  and
maintenance costs,  as well  as  present worth  cost.  Present
worth cost is the total cost of an alternative over time in terms
of today's dollar value.  Cost estimates are expected to be
accurate within a range of +50 to -30 percent.

State/Support Agency Acceptance considers whether the
State agrees with the EPA's analyses and recommendations,
as described in the RI/FS and Proposed Plan.

Community Acceptance considers whether the local
community agrees with EPA's analyses and preferred
alternative.  Comments received on the Proposed Plan are
an important indicator of community acceptance.
potentially reach ARARs in the active remediation area
of the plume sooner than Alternative G6.  However,
chemical-specific  ARARs  will be   attained  through
treatment and  certain natural processes (dilution and
dispersion)  for groundwater  in  all  three  of  these
alternatives.

Alternatives  G2,  G4,  and  G6 would  comply  with
location- and action- specific ARARs.
Long-Term Effectiveness and Permanence

Enhanced  bioremediation  under  Alternative  G2  is
considered a reliable method  for reducing  contaminant
concentrations  in  groundwater. In-well stripping  under
Alternative G4 and pump and treat under Alternative G6
are also considered effective  technologies for treatment
and/or  containment  of  contaminated  groundwater, if
designed and constructed properly.

All three alternatives rely on a combination of treatment in
the active remediation area, natural processes, including
dilution and dispersion for areas where active remediation
is not implemented, and institutional controls.

Enhanced bioremediation under Alternative G2 has been
demonstrated to be effective and reliable at numerous sites
for groundwater treatment for  CVOCs  in contaminated
areas.     However,  groundwater   concentrations  may
rebound if there is continued  migration  of CVOCs from
unknown  source   areas.     Enhanced  bioremediation
treatment may  be required over the  long-term to address
continued  migration of contaminants  from unknown
source areas into groundwater.

In-well air stripping under Alternative G4 is expected to
be effective and reliable to significantly  remove CVOCs.
However, the effectiveness of this alternative  is limited by
radius of influence (ROI) or "reach"  into the aquifer.  The
ROI will depend on pumping capacity of each well and
the hydrogeologic  characteristics of the Site.  The ability
to secure access to residential properties may impact the
placement of the in-well air stripping wells and ultimately
the effectiveness  of the  technology.  In addition, the
effectiveness of in-well air stripping may be limited in
shallow aquifers, due to the lack of vertical  space  in the
well  for  "stripping."   A  field pilot  study  would  be
necessary to determine pre-design  parameters such as
actual ROI, optimal well spacing, flow rates, and pumping
capacity prior to full-scale implementation.

Some residual risk above  levels of concern would remain
under  contaminated groundwater in  Alternatives G2 and
G4; these alternatives rely upon institutional  controls and
MNA  for protection. Residual  risk under Alternative G6
would likely be reduced below levels of concern over a
longer-term remedial time frame as natural attenuation
appears  to  be limited  and  contaminant removal  from
groundwater slower.

Reduction of Toxicity,  Mobility, or Volume Through
Treatment

Alternatives  G2, G4 and G6  reduce the toxicity and
volume of contaminants at the  Site through treatment of
contaminated   groundwater.    Alternative    G2   uses
                                                      10

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biological  processes   to   degrade  contaminants  in
groundwater to less harmful  compounds.  Alternative
G4 uses physical processes to remove the contaminants
from the aquifer, and provides  chemical treatment for
the collected vapor-phase contamination.  Alternative
G6 removes contaminated groundwater and treats it via
a carbon treatment process.  Alternative G2  does not
remove contamination from the saturated  zone,  while
Alternatives G4 and G6 do remove contamination.

Alternative G2 does  not reduce the mobility  of the
contaminants in groundwater and  Alternative G4  may
change the movement of  contaminants in groundwater
because the in-well air stripping treatment is expected to
create groundwater mounding.  Alternative G6 would be
the most effective at  reducing  the  mobility of the
groundwater  contamination  by  providing  hydraulic
control of the plume.

Each of the three active alternatives includes an MNA
component for the lesser contaminated portion  of the
plume outside the active remediation area.  MNA would
provide limited  further reduction  in  the  toxicity and
volume of contaminants in groundwater by transforming
them  into  less  harmful  substances  through  natural
biological, chemical and other processes.

During   the   enhanced   bioremediation  and  MNA
biological degradation processes, PCE, TCE and cis-1,2-
DCE could  be transformed into the more toxic vinyl
chloride under anaerobic  conditions in the subsurface,
prior to  aerobic degradation to the less toxic ethane.
This transformation would need to be  monitored and
managed to prevent exposure via drinking contaminated
water or inhalation through the vapor intrusion pathway.

After treatment, Alternatives G4 and G6 would generate
residuals in a form of used GAC that  would require
regeneration, destruction or disposal.

Short-Term Effectiveness

Alternatives G2, G4  and G6  may  have  short-term
impacts to remediation workers, the public, and the
environment during  implementation.   Remedy-related
construction (e.g., trench excavation) under Alternatives
G4 and G6 would require disruptions in traffic and street
closure  permits. In addition, Alternatives G4 and G6
have   aboveground   treatment   components    and
infrastructure that may create a minor noise nuisance and
inconvenience for local residents during construction.

Exposure of workers, the surrounding community and
the  local   environment  to   contaminants   during
implementation of the three alternatives  is minimal. No
difficulties  are foreseen with  managing  the required
quantity of the bioremediation injection material needed in
Alternative  G2,  as  it  is  non-hazardous.    Excavation
activities  in Alternatives  G4  and  G6  could produce
contaminated vapors that present some risk to remediation
workers  at  the Site.   Drilling activities, including the
installation of monitoring, in-well air stripping, injection,
and  extraction wells  for Alternatives G2,  G4, and G6
could produce contaminated liquids that present some risk
to remediation workers at the Site.  The  potential for
remediation  workers  to  have   direct  contact   with
contaminants  in  groundwater  could also  occur  when
groundwater remediation  systems  are  operating  under
Alternative G6. Alternative G6 could increase the risks of
exposure, ingestion and inhalation of contaminants by
workers  and  the  community   because  contaminated
groundwater would  be  extracted  to the  surface  for
treatment.  However, measures would be implemented to
mitigate exposure risks.

All  three  alternatives  include monitoring  that  would
provide the data  needed for  proper management of the
remedial processes and a mechanism  to  address any
potential impacts to the community, remediation workers,
and the environment.  Risk from exposure to groundwater
during excavation would  also require management via
occupational health and safety controls.

Groundwater  monitoring  and   discharge   of  treated
groundwater will have minimal  impact  on workers
responsible for periodic sampling.   The time required for
implementation of Alternative G6 is estimated at  6 -  9
months.  Alternatives G2 and G4 are estimated to take
about 9-12 months to implement.

RAOs would be achieved in Alternatives G4, G2, and G6
within   short,   medium   and   longer  time   frames,
respectively.  In-well air stripping is expected to achieve
groundwater RAOs   within  five  to  20  years   under
Alternative G4.  Enhanced bioremediation is  expected is
expected to achieve RAOs within  eight to 50 years under
Alternative  G2,  and  groundwater  pump  and   treat
technology is expected to achieve groundwater RAOs in
30 or more years under Alternative G6. The time frame to
meet groundwater RAOs  in  the  non-active remediation
area where MNA/LTM would be implemented is difficult
to predict, but is expected to exceed 30 years.

Implementability

All three technologies are  well-established technologies
that  have  commercially available equipment and  are
implementable.   All  three   alternatives  have  access
challenges that would have to be addressed with property
owners.    Of  the  three   alternatives,  Alternative  G6
Groundwater Pump  and Treat is  probably  the  easiest
alternative to construct at the Site and would require the
                                                     11

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least amount of street closure permits and would require
less land and disruption in residential areas. Alternatives
G2 and G4 would be moderately difficult to construct in
the residential areas, requiring securing access to homes
and  obtaining  street closure  permits.   The  need  to
reconfigure  the treatment  injection  and  in-well  air
stripping well locations  in Alternatives G2 and  G4 due
to access constraints map be possible, however doing  so
potentially impacts the  effectiveness  and schedule  of
these remedial alternatives.

All  alternatives  would  require  routine  groundwater
quality, performance and  administrative  monitoring,
including five-year CERCLA reviews.  Alternatives G4
and  G6 require periodic operations  and maintenance
(e.g., substrate injection, GAC replacement) for the life
of the treatment.

Cost

The  estimated capital cost, operation, maintenance and
monitoring (O&M) and present worth cost are discussed
in detail in the FS  Report. The cost estimates are based
on the  best available information.  Alternative Gl (No
Action)  has  no   cost  because   no  activities  are
implemented.   The present worth cost for Alternatives
G2  and G4  are  $15.8  million  and  $16.7  million,
respectively. The  highest present worth cost alternative
is Alternative G6, at $21.5 million.

The  estimated capital,  O&M and  present-worth costs
for each of the alternatives are presented below.
Alternative
G-l
G-2
G-4
G-6
Capital
Cost
$0
$4,344,000
$7,730,000
$2,997,000
Annual O&M
Cost
$0
$835,000
$730,000
$1,185,000
Present
Worth
$0
$15,830,000
$16,710,000
$21,560,000
State/Support Agency Acceptance

NYSDEC concurs with the preferred alternative.

Community Acceptance

Community acceptance of the preferred alternative will
be evaluated after the public  comment period ends and
will be described in the Record of Decision for this Site.
The Record of Decision is the document that formalizes
the selection of the remedy for a site.

PREFERRED REMEDY

Based upon an evaluation of the remedial alternatives,
EPA, in  consultation  with NYSDEC,  recommends
Alternative G6, Groundwater Pump  and Treat, as the
Preferred Alternative.  Alternative G6 has the following
key  components:  extraction  of  the  groundwater  via
pumping  and  ex-situ  treatment   of  the   extracted
groundwater prior to discharge to a POTW, surface water
or reinjection to groundwater (to  be  determined during
design);  in-situ chemical  treatment   of  targeted  high
concentration   contaminant   areas,   as   appropriate;
monitored natural attenuation for the  areas where active
remediation is  not  performed;  long-term  monitoring in
conjunction with implementation of institutional controls.
In addition, EPA will continue to evaluate the potential for
vapor  intrusion at  the Site,  and  will  install  vapor
mitigation systems, where necessary.

The groundwater extraction well network will be designed
to effectuate  removal of the contaminant mass from the
groundwater plume and establish hydrodynamic control of
the plume.  Figures  4 and 5 provide the conceptual pump
& treat well locations within the shallow and deep UGA
plume  areas.   The exact number of extraction wells  and
their placement will be determined  in the remedial design.
An aquifer pump test would be conducted as part of the
pre-remedial  design to collect  necessary  aquifer  data
necessary to complete the design of the groundwater pump
and treat system.

The  use  of in-situ  chemical treatments, targeting areas
containing  high concentrations  of PCE that may reside
outside the radius  of influence of the pump within the
inferred  plume, as  appropriate,  in  combination  with
groundwater  extraction  could  potentially  reduce  the
remediation time frames and the cost of this alternative.
The  implementation of in-situ  chemical treatment  (e.g.
ISCO,  ISCR) will be designed to enhance the remediation
of the  contaminated groundwater in conjunction  with the
pump  and treat system.    The  remedial  design   will
determine how best to execute the ISCR or ISCO with the
pump and treat system.

A treatment plant with the capacity to achieve the mass
removal and  hydraulic control objectives of the remedy
will  be constructed within or nearby the  Site.  EPA
estimates that a capacity of 350 gallons per minute may be
required. The extracted  groundwater would be treated for
CVOC removal with either liquid phase GAC or  air
stripping, or both.   Treated groundwater effluent will be
discharged  to a POTW, surface water, or reinjected to
groundwater.  The method of discharge will be determined
in the remedial design. The design of the treatment facility
will take discharge requirements into account.

The pump and treat  system would operate until MCLs are
attained in the shallow and deep UGA  at the Site. The FS
presents  calculations determining  the  duration  of the
operation of the extraction system.   These  calculations to
                                                     12

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determine the remedial time  frame require  additional
data regarding contaminant mass flux, as well as more
detailed process  design to determine the actual number
of recovery/injection wells and pore  volumes of clean
water  required to  reach  RAOs.   This data  will be
collected during the pre-remedial design phase.  EPA
assumes the duration of this alternative is  30 years or
more.

The environmental benefits of  the  preferred remedy
may be enhanced by consideration, during  the  design,
of technologies  and practices that are sustainable in
accordance with  EPA Region 2's Clean  and Green
Energy Policy1.    This  will include  consideration  of
green remediation technologies and practices,  including
GAC regeneration.

Monitored natural attenuation is a necessary component
in  those  areas  where  active   remediation  is  not
anticipated,  such as the  areas  of lower  contaminant
concentrations at edges of the contaminant plume.

A long-term groundwater monitoring program would be
implemented to  track  and  monitor  changes in  the
groundwater  contamination and ensure the  remedial
action objectives are attained. The results from the long-
term monitoring program  will be used to  evaluate the
migration and changes in the  contaminant plume over
time.    The  long-term  monitoring  program will be
modified accordingly.

The groundwater monitoring  well sample  results will
also be used to track changes in  the contaminant plume
in order to  determine homes  considered "at risk" for
vapor intrusion.   Selected structures/homes determined
to be "at risk" would be sampled periodically for  vapor
intrusion during the winter heating season.

Vapor  intrusion  caused  by  volatilization  from  the
groundwater contaminant plume  has been monitored by
EPA.  To date,  15  homes have  been sampled and  one
home has been outfitted with a vapor mitigation system.
These systems would be inspected periodically to ensure
that they  are  operating  properly.    A  review  of
groundwater and vapor data would  be relied upon to
determine  which   homes  without   vapor  mitigation
systems  would  be tested in that  year's monitoring
program.  These homes would  be monitored  through
collection of three samples (sub-slab, basement, and first
floor) at each building. Vapor extraction systems would
be  installed,  if warranted.  EPA  will   continue  to
investigate the soil vapor intrusion pathway at the Site.
1 See http://epa.gov/region2/superfund/green_remediation.
Institutional controls are incorporated  into this  remedy
for protection of human health and the environment over
the  long  term.    EPA  anticipates  using  existing
government controls to prevent use of groundwater and
informational and or governmental controls to ensure that
vapor intrusion issues are identified.

While this alternative will ultimately results in reduction
of contaminant levels in groundwater to levels that would
allow for unlimited use and unrestricted exposure, it will
take  longer than five years to achieve these levels.  As a
result, in accordance with EPA policy, the Site is  to be
reviewed at least once every five years.

Basis for the Remedy Preference

EPA is proposing Alternative G6 due to the difficulty in
implementing  Alternatives G2 and G4  in the densely
populated and fully-developed residential and commercial
setting of the Site.  Alternative G2, and Alternative G4 to
a somewhat lesser degree, would require securing  access
to a significant number of residential properties to perform
construction activities.  Under Alternatives G2 and  G4,
access would be necessary to the residential properties for
an  extended  period  of time  to perform  the  initial
construction  activities   and  to  subsequently  conduct
monitoring.  Under Alternative G2, multiple injections are
likely to be  necessary over time.  These activities  would
cause  a  significant  disturbance  to  the   residential
neighborhood. Reconfiguration of the injection or in-well
stripping wells due to access constraints could potentially
impact significantly the  effectiveness of the  technology.
Access to  install  extraction  wells under  the  preferred
remedy, Alternative G6 Groundwater Pump and  Treat,
though still complicated, is more manageable. Access to
property and construction of the treatment plant would be
performed  in  an  area zoned  for  commercial  activity.
Furthermore, the  uncertainty  of an  unknown  source
investigation that could result in a continued migration of
contamination from source areas adds to the uncertainty
that the remedial action objectives would be achieved with
Alternative G2.

Alternative  G6,  Groundwater Pump  and  Treat, uses
proven technologies that can be more readily implemented
than the other alternatives. The treatment components can
be  expanded  to  improve  treatment effectiveness  or
decrease   the   remedial  time   frame,   if  required.
Groundwater Pump and Treat has been demonstrated as an
effective remedial approach for contaminant mass removal
over the long term.  This approach would be particularly
effective   as  the   contaminant  plumes   are  relatively
accessible and have a specific configuration.  The shallow
UGA groundwater (0 to 20  feet bgs)  PCE  plume is
approximately 3,500 feet long and between 400 and 100
feet wide. The deep groundwater plume is approximately
                                                     13

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1,110 feet long.  Groundwater Pump and Treat would
also be  the  most  effective  of the  alternatives  in
establishing  hydrodynamic  control  of  the  aquifer  to
minimize off-site migration of contaminants  and isolate
the contaminated groundwater area.  The prevention of
off-site migration would prevent  CVOC contamination
from flowing toward the LIAWC well field.  Long-term
groundwater  monitoring would  ensure  that  remedial
action objectives are achieved at the Site.

The preferred remedy is more expensive than either
Alternatives G2 or G4.   However,  there is a greater
degree of uncertainty that the remedial action objectives
would  be achieved by  both Alternatives G2  and G4.
Based   on  the   Site   conditions,   Alternative  G6,
Groundwater Pump and Treat,  is the most effective of
the alternatives.

The addition  of in-situ  chemical treatments  targeting
areas containing high concentrations  of PCE that  may
reside outside the radius of influence of the pump within
the inferred plume, as appropriate, in combination  with
groundwater  extraction  could  potentially reduce  the
remediation  time frames by reducing the contaminant
mass of PCE, and, therefore,  the costs of this alternative.

EPA, in conjunction  with  NYSDEC,  believes  that
Alternative G6, Groundwater Pump and Treat, would be
protective of human  health  and  the  environment,
provide the  greatest long-term effectiveness,  comply
with ARARs,  and be cost-effective among alternatives
with respect to the evaluation criteria.  The preferred
remedy also will meet the statutory preference for the
use of treatment as a principal element.
                                                     14

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Site Location - Peninsula Boulevard Groundwater Plume RI
        Town of Hempstead, Village of Hewlett
            Nassau County, New York

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                                    SHALLOW UGA PLUME MAP
             FEASIBILITY STUDY
PENINSULA BOULEVARD GROUNDWATER PLUME
      TOWN OF HEMPSTEAD, VILLAGE OF HEWLETT,
            NASSAU COUNTY, NEW YORK
        Honnlngson, Durham &
        Richardson. Architecture and
        Engineering, P.O. InAssoclaHon
        with HDR Engineering, he.

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                               T
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Honnlngson, Durham &
Richardson. Architecture and
Engineering, P.O. In Association
with HDR Engineering, he.
         DEEP UGA PLUME MAP

              FEASIBILITY STUDY
PENINSULA BOULEVARD GROUNDWATER PLUME
       TOWN OF HEMPSTEAD, VILLAGE OF HEWLETT,
             NASSAU COUNTY, NEW YORK
                                                                                  DATE
                                                                                      06-23-2011
                                                                                  FIGURE

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Honnlngson, Durham &
Richardson. Architecture and
Engineering, P.O. In Association
with HDR Engineering, he.
SHALLOW UGA PUMP & TREAT LOCATIONS

                 FEASIBILITY STUDY
    PENINSULA BOULEVARD GROUNDWATER PLUME
          TOWN OF HEMPSTEAD, VILLAGE OF HEWLETT,
               NASSAU COUNTY, NEW YORK
                                                                           DATE
                                                                               06-23-2011
                                                                           FIGURE

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>^b^4
                                 Honnlngson, Durham &
                                 Richardson. Architecture and
                                 Engineering, P.O. In Association
                                 with HDR Engineering, he.
DEEP UGA PUMP & TREAT LOCATIONS

              FEASIBILITY STUDY
 PENINSULA BOULEVARD GROUNDWATER PLUME
       TOWN OF HEMPSTEAD, VILLAGE OF HEWLETT,
             NASSAU COUNTY, NEW YORK
                                                                                                             DATE
                                                                                                                 06-23-2011
                                                                                                             FIGURE

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