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My staff and I are available to discuss this matter further with
you at your convenience.

Attachment

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               EXPLANATION OF  SIGNIFICANT  DIFFERENCE

                     REICH FARM Superfund  Site
             Dover Township, Ocean County, New Jersey


INTRODUCTION

The purpose of  this  Explanation of  Significant  Difference  (ESD)
is to explain  the United-States Environmental .Protection Agency's
 (EPA's) changes to the groundwater  remedy selected in its
September 30,  1988 Record of  Decision  (ROD)  an'd the  subsequent
1995 ESD..'for the Reich Farm- Superfund  Site (Site or  Reich Farm.
Site) ... The. ROD called, for.  extraction  of. contamin-ated..ground-
water, treatment via air stripping  and carbon ..adsorption, and
reinjection of  the treated  ground-water.   The ROD also called  for
remediation of., the contaminated soil on-site through low
temperature thermal  desorption.   The portion of the  cleanup
addressing the  soil  was not modified, by the.1995 ESD.

In 1995, EPA modified the'ROD" by issuing  an-ESD. A  proposed ESD
was issued to  the public ..n August  1995,  and comments from the
public were addressed during  an August 16,  1995 public meeting.
A responsiveness summary was  prepared  to  address questions
related to the  modification.   The majority of commentors
supported the modification  of the remedy  as described in the 1995
ESD.

The selected remedy, as modified by the 1995 ESD, called for
ground water extraction from  existing  public supply  wells, and
treatment of the contaminated ground water through an air
stripper located at  the United Water Toms River's (UWTR's)
Parkway Well Field  (Well Field)  and distribution of  the treated.
ground water to the  municipal water supply.  The modification  to
the remedy,  described in the  1995 ESD,  did not  require the  ..
construction of a groundwater pump  and treat system  as called  for
in the original ROD.

The 1995 ESD also indicated that the Well Field treatment  system
would be monitored closely  and upgraded,  if necessary, to  ensure
that the public water supply  meets  all state and federal safe
drinking water  standards.

Currently, there are six wells (#22, #24,  #26,  #28,  #29, and #44)
in the Parkway  Well  Field that draw water from  the Cohansey
aquifer.  In 1996, the New  Jersey Department of Environmental
Protection (NJDEP) and the  New Jersey  Department of  Health and
Senior Services (NJDHSS), as  part of an intensive study of the
Dover Township  water supply,  found  additional  low level chemical
contamination,  in. water, from Well #26..   The. contaminants, were .  .
. sent i£ied;.as. by-products. of>Mix acT^lqTjitrile/atvrene;., reactions. > .
It was .also. deterrained".tha.t these, compounds-.were- disposed-of at- -
the Reich Farm. Site. ' :As there are  no  existing  state- or  federal'-'.
drinking water  standards for  these  compounds and very little is

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known on  their  toxicity, UWTR agreed', as a precautionary measure,
to close  the  two wells  (#26 and #28) that are capturing the Reich
Farm ground, water plume.  When operating, Wells #26 and #28 have-
effectively protected the Well Field's remaining four Cohansey
wells from contamination.  Since Wells #26 and #28 were closed,
the remainder of. the Parkway Well Field's wells were closed to
pr=--.-ent the plume from  spreading to them.  Potable water was
supplied  from, other, well fields during, this. time, period.

Due to public concerns  in Dover Township regarding an apparent
elevation in  childhood  cancer, cases, and .in.recognition.of the
unknown..toxicity of the recently identified compounds, EPA and"
the State agencies believe it prudent to be very conservative on
environmental matters in the area.  Therefore EPA has chosen.to
modify the remedy described in the 1995 ESD,  so that the water
from Wells #26.  and #28  undergoes further treatment that includes
an activated  carbon system.  The activated carbon system removes
the recently  identified compounds to below detectable levels. As
Maximum Contaminant: Levels. (MCLs) do nof exisf for the recently
identified compounds, the activated carbon units will remain in
operation until the concentrations of the recently identified
compounds are no longer detected in ground water from the wells
or are determined.to., be at an acceptable risk level in Wells #26,
#28,  and  in the monitoring wells within the Site's ground water
plume.

This ESD  also allows the treated water to be distributed as
potable water supply, discharged to a designated recharge area,
or discharged to the Toms River at the discretion of the State
and local authorities.

Groundwater from all other Well Field wells that are shown to
have no detectable levels of the recently identified compounds,
or are at acceptable risk levels and that meet all other state
and federal drinking water standards, will be available for use
as potable water supply.  Furthermore, if ground water from any
other Well Field well is found to contain site-related
contaminants  at levels  deemed to be unsafe, additional treatment
as necessary  will be provided to ensure compliance with all state
and federal safe drinking water levels.

EPA issues this ESD in  accordance with Section 117(c) of the
Comprehensive Environmental Response, Compensation and Liability
Act of 1980,  as amended (CERCLA), 42 U.S.C. §9617(c), and Section
300.435 (c) (2) (i) of the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), 40 C.F.R. §300.435(c) (2) (i) .

Site Location, History, Contamination Problems, Selected Remedy

~:ie: Reich'"Farm property/ which''.comprises" parcvdr"1 the' bveradl*
Sitei-.--.is-.located.-oh Lakewood-1 Road'in the Pleasant  Plains section

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of Dover Township, New Jersey.   The property encompasses  three
acres and is surrounded by commercial .and residential areas.

In December 1971,  approximately 4,500 drums  containing wastes and
450 empty drums  from Union Carbide Chemicals'  (UCC's)  Bound Brook
chemical manufacturing facility were discovered at  the Site.  In
1972 and 1974, UCC removed the  drums and some contaminated  soil
from the. Site.

In 1974, the Dover Township Health Department  .(now  the Ocean
County Health Department)  issued a zoning ordinance- restricting
private, well .use around, the. Site. due. to. contamination.-, found: in
the. ground water.  Currently, all residences and businesses
within the area  affected by groundwater contamination associated
with .the. Site are  connected, to  the public water supply.   The
public water supply has continuously met the federal and  sr.ate
safe drinking water standards . .

In September 1983 , EPA" included the Reich- Farm Site on its
National Priorities List of Superfund Sites.   In 1986,  EPA
commenced a Remedial Investigation and Feasibility  Study  (RI/FS)
at the Site pursuant to CERCLA,  in order to  identify the  nature
and extent of contamination, and to develop  cleanup alternatives.
The RI confirmed the presence of groundwater and soil
contamination.   Contaminants identified in the groundwater  and
soil included 1, 1, 1, -trichloroethane,  trichloroethene,  and
tetrachloroethylene.   These chemicals are hazardous substances
within the meaning of  Section 101(14)  of CERCLA,  42 U.S.C.
§9601(14} .

On September 30, 1988,  EPA issued a ROD that described the
selected remedy  for contaminated ground water and soil at the
Reich Farm Site.   The  remedy called for the  following:..

(1)   additional  groundwater and soil sampling to further
     delineate contamination related to the  Site;

(2)   the excavation and treatment of contaminated soil by
     enhanced volatilization  (thermal desorption) to remove
     volatile organic  compounds (VOCs)  and semivolatile organic
     compounds ;  and

(3)   the installation  and  operation of a groundwater pumping,
     treatment and reinjection  system to remove VOCs from ground
     water at the  Site.

POST -ROD ACTIVITIES
        a, issuance. -or. che.-.RCPv.. EPA'/entered-^'int'ov av.-:j:.udi:cial<. •' . '
•Jonsent. .Decree .with.. UCC. in., September: 198.9 for -performance: of • -.-
remedial design and construction; of: the-'selected- "remedy ..  The.'

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decree was entered  by  the  federal district court of New Jersey on
March 28, 1990.

Since the issuance  of  the  ROD, UCC conducted two phases of pre-
design activities.   Phase  I, which was conducted during 1990-1992
and summarized  in the  May  1992 Remedial Design/Remedial Action
Report,  included additional soil and groundwater sampling to
further  delineate the.  extent of. contamination.  Based on the
sampling results, EPA  concluded that:  (1) groundwater.
contamination from  the Site extends approximately one-mile south
to the UWTR Parkway Well Field; .and.  (2) the: volume of/   .
contaminated, soils  at.  the  Site, was .approximately.. 15, 000" cubic
yards  (which significantly exceeded the initial estimated ..volume
of 2,000 cubic  yards).

Phase II activities included a thermal desorption treatability
study for soil  treatment.  The thermal treatment of the 15,000
cubic yards of.contaminated soil.and restoration of the Reich
Farm property was completed in May 1995'.  Phase II activities
also included an evaluation of groundwater remedial design
scenarios based upon the results of the Phase I sampling and
modeling.  This evaluation is. presented in a February 1995 report
entitled "Evaluation of Groundwater Remedial Design Scenarios."

The groundwater data collected and the modeling done during the
two phases of pre-design work increased EPA's understanding of
the movement and configuration of the groundwater contaminant
plume.  Based on this  information, EPA issued the 1995 ESD.

In 1996 and 1997, additional information was collected regarding
the contaminants comprising the plume.  Additional site-related
compounds were  identified  in two wells within the Well Field
(Wells #26 and  #28) .   The  toxicity of these compounds, which were
found in low part per  billion concentrations, is unknown.  As a
conservative precautionary measure,  NJDEP has recommended that at
this time,  the  water from  these wells should not be used as
public water supply unless necessary to meet the public's demand
for potable water.   However, Wells #26 and #28 must continue to
operate to ensure the  protection of the remaining wells
comprising the  Well Field  (Wells #22, #24, #29 and #44).  In
addition, Wells #26 and #28 must operate to facilitate the
ultimate cleanup of the groundwater plume.

In May 1997,  UCC added activated carbon treatment following the
air stripper treatment system at the Parkway Well Field.
Effluent sampling has  shown that activated carbon effectively
treats the recently identified compounds to non-detectable
levels, at an analytical..detection.-limit..of 100:parts per..
-ril'liarr... .;••• •..,   -.  •

In addition,  due to. special'.'public, health' concerns in. Dover-
Township, EPA chose to evaluate several discharge options for the

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 water from Wells  #26  and  #28.  One option was determined  to  be
 immediately implementable. Currently,. after  treatment,  the water
 from Wells #26  and  #28  is discharged  to  the  ground on  an  area
 close to  the intersection of Route 9  and the Garden State Parkway
 (discharge area).   To date, inspection, of the discharge area
 indicates that  the  treated water is being adequately recharged to
 the  aquifer.  EPA and NJDEP will evaluate the discharge via
 confirmation of.modeling-and..effects  on  the  discharge  area  (i.e.,
 recharge  effectiveness) and on other  public  wells in. the  area  to
 determine if a  discharge  line should  be  extended to the Toms
 River... At NJDEP's  discretion, the treatedwaterrmayalso.be used.
 as a source of,  potable-water.


 Wells #22.,  #24,. #29,  and.  #44 were sampled and analyzed in May
 1997.  Samples  collected  frcT. Wells #29  and  #44 were found to
 contain levels  of radiological contamination above the Federal
 safe drinking water levels. (MCLs). .  NJDEP and EPA suspect this
 may  be due to high  levels of naturally occurring radium 224.   The
 radiation is not  due  to any contamination at the Reich Farm  Site.
 Compliance for  radiological compounds is not based on  samples
 collected from  each individual well;  rather, the MCLs  must be  met
 after the water from  the  respective wells is blended within  the
 water distribution  system.  After blending,  the water  from the
 Parkway Well Field  meets  the MCLs for radiological compounds.

 The  data  collected  from Wells #22, #24,  #29, and #44 demonstrate
 that the  recently identified compounds have  not been detected  in
 these wells.  The water from these wells meets all safe drinking
 water  criteria  prior  to distribution; therefore, these wells are
 being used as public  potable water supply.   A contingency plan
.will  be put  in  place  to ensure that action is taken in the
 unlikely  event  that these wells become contaminated with  site-
 related compounds at  levels that would cause an unacceptable risk
 to human  health.

 DISCUSSION OF SIGNIFICANT DIFFERENCES

 EPA,   in recognition of the special health concerns in  Dover
 Township,  and after consultation with the NJDEP, modifies the
 groundwater remedy  as described in the September 30, 1988 ROD  and
 previously modified in the 1995 ESD as follows:

 *     The  Well Field's groundwater treatment  system has been
      upgraded by  including an activated  carbon system  after  air
      stripping  to treat' the entire groundwater plume emanating
      from the Reich Farm  property.

      Rather than.vdi-strifautingvthe t^ra*c^d/.wa,ter.;to';,ciies;aruaicipal .•:,
     water supply (as., presented iiuthe:.1395., ESDF, this ESD1"
     provides three options.? recharge-of the treated water  to  the
      aquifer via  the  discharge area;  discharge of the  treated

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The modified remedy complies with the federal and state drinking
water standards as specified- in the ROD.  In addition, the
modified remedy is technically feasible, and provides treatment
that permanently and significantly reduces the toxicity, mobility
and volume of-hazardous substances in.the groundwater.
Jeanne. K. F
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