v>EFV\
            United States
            Environmental Protection
            Agency
            Office of
            Emergency and
            Remedial Response
EPA/ROD/RO1-83/007
September 1983
Superfund
Record of Decision:
            Sylvester Site, NH

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            TECHNICAL REPORT DATA          
          (PlefUe rtfld Instructions on the revene IHfore completing)     
1. REPORT NO.       12.          3. RECIPIENT'S ACCESSION NO.
.. TITLE AND SUBTITLE               5. REPORT DATE     
SUPERFUND RECORD OF DECISION:           09/22/83     
Sylvester, NH (Supplemental ROD)        6. PERFORMING ORGANIZATION CODE
7. AUTHORIS)                 8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS        10. PROGRAM EL.EMENT NO.  
                    ". CONTRACT/GRANT ~O.  
12. SPONSORING AGENCY NAME AND ADDRESS        13. TYPE OF REPORT AND PERIOD COVERED
U. S. Environmental Protection Agency                 
401 "M" Street,  S. W.            14. SPONSORING AGENCY CODe 
Washington, D. C.  20460                     
15. SUPPLEMENTARY NOTES                     
16. ABSTRACT                          
  The Gibson Road hazardous waste dump site is located in the City of Nashua, New
Hampshire. The  6 acre site has been used as a sand borrow pit for an undetermined 
number of years.  Some time during the late 1960's the operator of the pit began an
unapproved and illegal waste  disposal operation. Household refuse, demolition 
materials, chemical sludges,  and approximately 900,000 gallons of hazardous liquid 
chemicals were dumped at the  site. The ground water, air and to a lesser extent 
surface water have been contaminated.                 
  The original ROD was signed in July 1982 approving the installation of a slurry
wall and surface cap as the first operable unit. The ROD also approved ground water
treatment as the second operable unit but deferred selection of the specific treatment
process until the  technical analysis and evaluation of the pilot plant studies were
complete. The cost-effective ground water treatment system selected for this site 
includes: inorganic chemicals removal; volatile organic chemicals removal; concen-
trated organic chemicals removal; and biological treatment of the sidestream. Also
a treatment rate of 300 gpm has been selected to reduce the operating time to 
approximately 2 years.                     
17.           KEY WORDS AND DOCUMENT ANAL.YSIS      .  
a.      DESCRIPTORS       b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Record of Decision                       
Si te Name : Sylvester, NH (Supplemental ROD)              
Contaminated media: gw, sw, air                 
Key contaminants:  volatile organics,                 
inorganics, heavy metals                     
18. DISTRIBUTION STATEMENT        19. SECURITY CLASS IT/lis Repo,,/ 21. NO. OF PAGES 
                None            
                20. SECURITY CL.ASS (TlJis page) 22. PRICE  
                None            
EPA 'ewlll 2220-1 (Rn. .-n)

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INSTRUCTIONS
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significant bibliography or literature survey. mention II here.
17. KEY WORDS AND DOCUMENT ANALYSIS
la) DESCRIPTORS - Select from the Thesaurus of Engineerir.~ and Sdenlll'k Terl'" the prupel aUlh"r,,,'d 1"1111' Ihatldenllfy the maJOI
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Insert the price set by the National fechnicallnformation Scrvl~e ur the Government Prlnllng OITi~e, ,I' known,

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Supplemental Record of Decision.
Ground Water Treatment Alternative Selection
Site:
Sylvester Site, Gilson Road, Nashua, New Hampshire
Analvses Reviewed:
I have reviewed the following documents describing ~he analysis of
cost effectiveness of remedial alternatives at the Sylvester Site:
-AA OSWER Record of Decision on Remedial Alternative Selection
for the Sylvester Site dated July 29, 1982.
-Sylvester Hazardous Waste Dump Site Containment and Cleanup
Assessment, Roy F. Weston, Inc., Jan~ary 1982.
-Supplemental Study to Final Report on Sylvest~r Hazardous
Waste Dump Site Containment and Cleanup Assessment, Roy F.
Weston, Inc., July 1982.
-Gilson Road Ha%ardous Waste Dump Site Pilot Plant Treatment -
Study Pilot Plant Design, Roy F. Weston, Inc., October 1982.
-Gilson Road Hazardous Waste Dump Site Pilot Plant Treatment -
Final Report, ROY F. Weston, Inc., May 1983.
-Gilson Road Hazardous Waste Dump Site Pilot Plant Treatment -
Addendum to Final Report, ROy F. Weston, Inc., June 1983.
-Gilson Road Hazardous Waste Dump Site Treatment Concerns
Report, ROy F. Weston, Inc., September 1983.
-Feasibility and Cost Evaluation of Alternative Scheme for
Ground Water Flow Regime Manipulation, Goldbe~g- Zoino ,
Associates, Inc, September 1983.
-Staff summary and recommendation.
Summary of Original ROD:

The original ROD was signed in July of 1982. It selected
the installation of a slurry wall and a surface cap as the first
phase of remedial action. The ROD approved ground water treatment
as the second phase of remedial action but deferred selection
of the specific treatment process until the State could complete

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Components of the Selected Treatment Process:
Ground
Water Extraction and Treatment @ 300 gpm.
Chemical precipitation of heavy metals
pB adjustment
Sand Filtrati"on
8igh temperature air stripping of volatile organics
Incineration of vapors from ai~ stripping process
Recirculation of 250 gpm of treatment plant effluent within
the slurry wall. (Recharging: less water back into the
containment area will induce ground water flow into the
containment area through the bedrock structure.)
Biological treatment of SOgpm of treatment plant effluent
and injection into the ground water outside the slurry wall.
(Additional biological treatment is necessary because it
is discharged outside the slurry wall.)
Dewatering and on-site disposal of' sludge generated from
chemical precipitation and biological treatment processes*
Operation of the system to complete the remedial action.

*Based on the pilot plant study, the sludge produced by the
treatment plant will not be hazardous. Bowever, if the sludge is
found to be hazardous, it will be transported off site to an approved
hazardous waste treatment or disposal facility. '
Declarations:
Consistent with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), and the National
Oil and 8azardous Substances Contingency Plan, I have determined
that the ground-water treatment action, in conjunction with previous
remedial actions taken on the site, is cost effective, and provides
adequate protection of.tha public health and welfare, and of the
environment. I have also determined that the action being taken
is appropriate when balanced against the need to use Trust Fund
money at other si,tes.
I have determined that treatment of the ground water contained
within the slurry wall is necessary because the leakage of contam-
inants under the slurry wall (through fractures in the bedrock) is
expected to continue and because the long term integrity of slurry
wall installation at this hazardous waste site cannot be predicted
at this time.
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Office of
Lee M. Thomas
Assistant Administrator
Solid Waste and Emergency
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Sylvester Site
Staff Summary for the Supplemental
Record of Decision on Ground Water Treatment
Site. Description and History
The Gilson Roed hazardous waste dump site is located in tne
City of Nashua, New Hampshire, off Route 111, in the south ~aster1y
corner of that community. See Figures 1 and 2 for its location.
The 6-acre site had be~n used as -a sand borrow pit for an undete~ined
number of years. During the late 1960's, the operator of the pit
began an unapproved and illegal waste disposal ~~eration, apparently
intending tQ fill the excavation. Household refuse, demolition
materials, chemical sludges, and hazardous liquid chemicals all
were dumped at the site at various times. The household refuse
and demolition material were usually buried, while the slupges and
hazardous liquids were either mixed with the trash or were allowed
to percolate into the ground adjacent t~ the old sand pit. Some
hazardous liquids were also stored in steel drums which wer~ either'
buried or placed on the ground surface.
The illegal dumping at the site was first discovered in late
1970. After several court appearances and court actions, an injunc-
tion was issued in 1976 which ordered the removal of all materials
from the site. This injunction was ignored by the operator.
The first indication that the illegal dumping had included
hazardous wastes came in November 1978 when State personnel observed
drums being stored at the site. A court order was issued in October
1979 prohibiting all further disposal of hazardous wastes on the
site.
It is impossible to estimate the total quantit.ies of waste
materials discarded at the site. However, it has been documented
that over 800,000 gallons of hazardous waste were discarded there
during a ten month period in 1979.
In 1981, initial investigations showed that there were high
concentrations of heavy metals 'and volatile and extractable organics
in the ground water under the site. (See Table 1.) The contamination
formed a plume in the ground water which was moving from the site
toward Lyle Reed Brook at the rate of 0.8 to 1.6 feet. per day.
When the volatile hazardous chemicals reach Lyle Reed Brook,
they begin to volatize into the atmosphere. The rate of volatili-
zation and exposure to the surrounding community was modeled.
Based upon this analysis it was determined that volatilization of
organic pollutants from Lyle Reed Brook will be well above acceptable
limits. Chloroform exceeds life-time exposure levels by 100 times.
Exposure from methylene chloride and ethylene chloride are high

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Under the no action alternative, dilution of organic and
inorganic contaminants were not sufficient to eliminate health
hazards for the Lowell, Massachusetts, water system users. The
arsenic concentration, which was above water quality criteria, was
expected to increase by a factor of seven. The water quality
criteria for methylene chloride, chloroform, 1,2-dichloro-ethane,
trichloroethylene anQ benzene cumulati~ely would have been exceeded
by a factor of 7.3. Also, Lyle Reed Brook would not be able to
support aquatic life. In the Nashua River, concentrations were
expected to approach 40 percent of the accute acceptable limits
during the summer months. During periods of extreme low flow fish
kills were predicted.
Due to the ground water plume migrating from the site to the
Nashua River, all ~rivate drinking water wells hydraulically be~ween
these locations are unsuitable for use..
Community Relations 

The public has supported the remedial actions already taken
and those proposed in this Record of Decision (ROD). Local citizens
have, however, urged the State to initiate action as soon as possible.
. EPA communicated its acceptance of the selected remedial actions
at a pub~ic meeting on March 30, 1982. Approximately 150 people
attended. A meeting will be held in October to review the design
of treatment system with the community.
Enforcement Actions
The State has taken the lead on enforcement actions on this
site. A jury awarded $14 million in a State court action. It is
highly unlikely, however, that defendants in this matter have
assets sufficient to satisfy the court decision.. Region I has
initiated a generator search to identify the generators who sent
waste to Cannon's Engineering, which was the main source of waste
at Nashua. The search should be completed by November 1983.
Previous Actions
During May and June of 1980, the 1314 drums which were
accessible were removed by a contractor and disposed of at approved
sites in New ~ork and ohio. This action was funded by EPA under
section 311 (k) of the Clean Water Act.
In November of 1981, EPA used CERCLA emergency funds to install
a ground water interception and recirculation system at the site
to retard further migration of the contami~ant plume until remedial
action could be. implemented. This system was operated until October
1982, when the slurry wall was completed.
The State of New Hampshire completed a remedial investigation

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in January of 1982. They completed a supplement to that study
. in July of 1982, providing additional information on the costs
associated with various ground water treatment rates.
A ROD was signed by the AA, OSWER in July of 1982. The
activities approved in th~-ROD were funded through an amendment to
the Cooperative Ag~eement.
The selected remedial action included
the 20 acre sl~rry wall and surface capas
remedial action plan. The State completed
slurry wall and cap in December of 1982.

The _BOD. also approved ground water treatment, in principle,
but deferred the selection of the optimum treatment process until
after the State had completed its technical analysis and
evaluated the pilot plant studies.
the installation or
the first phase of the
construction of the
The pilot treatment plant has now been constructed and operated-
for a year. Studies to determine the process train for the treat-
ment plant were completed in June of 1983.
Current Status
The slurry wall is effectively. preventing migration of contam-
inants contained in the overnurden aquifer. However, it is not
entirely preventing contamination from leaking into the fractured
bedrock aquifer below the containment area and, thus, under the
slurry wall. This was anticipated and is addressed in the treatment
plant design by diverting part of the treated effluent (50 gpm) to
ground water outside of the slurry wall. This sidestream will
induce ground water flow into the slurry wall through bedrock
fractures eliminating further contaminant leakage. out of the
containment area. The current leakage rate of 30,000 - 55,000 gpd
does, however, make it important that construction of the treatment
plant be started as soon as possible.

Another factor requiring rapid construction is that many of
the hazardous substances inside-the site are destructive to the
slurry wall. Therefore, the treatment plant should be started as
soon as possible to protect the effectiveness of the slurry wall.
Ground Water Treatment
The 100 gallon per minute (gpm) treatment plant proposed
in the original Record of Decision was expected to require 6.2
years of operation at an annual operating cost of $750,000 and
a life-cycle cost of $6,788,000. A larger plant was evaluated
that would shorten the period of the remedial action. A shorter
treatment period is advantegeous because it would attain the
performance objectives sooner and provide better protection of the

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30QJ£.~<;i~~e!:Lt.ne..-op.e.rating... time__.t:.9":._L.1.._~ars, which completes
the remedial action significantly sooner at a com~arable life-cycle
cost ot $7,097,000. The 300 gpm plant is now being recommended
for implementation. Table 1 and 2 display capital ana operational
costs.
The estimated cost of the recommended system is cClr":;',,H'al:>le t~,j
the original system. the co.s..t ot both systems may. ~~.r.~~,7~t..~b=
r.edl,1_~e.~_o.~w.Q-1...c!"~..Q...rs that have not been' included in:i112 '.:.')'::::
estimates: FirstL-.thiL-e..,q1,1j.~~I1~ probably will retain 31: :.='.: . ...d
resale_or $~9.EL.y~l_ue (possibly as much as half the' ':~""":
purchase price after two years). Second, the current . -~. ..._.~
tor a ~ tU1"'h; nA g.a.n.az:.~ that will use waste ste:<" t-:> ~,:n'=~a'~'=
electricity. whoen that elec:.t_;'.~-<;.~J;:l._~~.~.Q!-d to the lc::a1 utilitJ',
the project is expected to realize net revenues of app~~xima~~li
$100,000 per year. Neither ot these potential revenue scurc~s ~as
been included in th~ lite-cycle cost estimates for these systems.

...
. Based on the risk assessment it was aetermined that the
following reductions inside the containment area are necessary to
adequately protect'public health and the environment:
Total organic Carbon
Chloroform
Methylene Chloride
Benzene
1,2-dichloroethane
Trichloroethylene
l,l,l-Trichloroethane
Acetone
Isopropanal
Arsenic
90%
95%
90%
90%
90%
90%
90%
90%
75%
90%
The Region I Administrator has concluded based 0" the
Nashua teasibility studies that the concentrations remaining in
the site after the treatement is stopped will not pose a substantial
present or potential hazard to human health or the environment.
(Analysis is attached.) The analysis used the criteria of Part
264.93 of the ~CRA Land Disposal Regulations.
Volatization from Lyle Reed Creek will be reduced to acceptable
exposure levels. Arsenic and organic concentrations will be reduced
to below water quality criteria at Lowell, Massachusetts. The
likelihood of tish kills in the Nashua River will diminish as tne
plume migrates into the river. Lyle Reed Brook will not meet
water quality criteria levels but an expanded aquatic population is
expected. Finally, all t"esidences using around W-'lT~1'" -'11"'8 tt1reat.e.fl~d

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After one and a half to two years of operations, the treatment
system will be evaluated for the following:
o
The degree to which treatment goals have been met for
the ground water within the slurry wall contairumen~ area.
o
o
The lopg-term integrity of the slurry wall.
The amount ot ground wa~er flowing through th~ con~ainmen~
area.
w~ exp~ct to attain the designated removal rates inside the
contai~ent area after two years of plant operation. This
5u~~~~~ental ROD approves operation of the treatment system tor two
years. At the conclusion ot the evaluation, the State and Region
I will evaluate the concentration limits and will recommend elther
that the treatment plant be shut down or_~_hat its opera~01'lOe-'-
contlnued. . .
- .....--'-"
The basic steps of the recommended grouna water treatment
system are:
o
inorganic chemicals removal
volatile organic chemicals removal
concentrated organic chemicals incineration
biological treatmen~ of ~he sidestream
o
o
o
The inorganic chemical removal stage is designed to remove
iron and manganese from the ground water. This is necessary to
prevent fouling of down stream equipment. An additional benefit
of this process is the removal of some of the other heavy metals
such as arsenic and lead. This step of the treatment system consists
of chemical precipitation of heavy metals, pH adj ustmen~' of the
waste water, and sand filtration to remove the preci~itated metals
sludge. A sample of th~ sludge has been analyzed using the standard
EP-toxicity procedure and was found to be non-hazardous. Samples
of the sludge from the full-scale plant will be tested. The
sludge will be taken to a RCRA approved treatment or disposal
facility if it is found to be a hazardous substance.
The next step in the process is the removal of the volatile
organic compounds using a high temperature air stripper (HTAS). The
contaminated ground water (which has had the metals removed from it
in the previous process step) is preheated in two heat exchangers,
an economizer and a trim heat exchanger. Over the range of operating
temperatures tested, all of the ~riority pollutants and more than
75 per cent ot the alcohols were removed from t~e waste water.
The vapor leaving the top of the HTAS will then go directly
to a fume incinerator for the removal of the concentrated volatile
organic chemicals. The incineration step of the treatment system
includes a horizontal fume incinerator, usin~ #2 fuel oil as
supplemental fuel, a waste hea~ recovery boiler and a 250KW turbine

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to incineration, but was found to be more costly and less reliable.
The incineration process is a well established method for handling
vapor-phase organics while avoiding operational problems in meeting
stack discharge limits. The turbine generator is expec~ed to be
cost-effective for a flow rate of 300 GPM with a payback period
of less ~han the expected operating life of the facility.

After the, waa~e water discharged from the HTAS is split into
two waste streams, the larger stream (of 250 gpm) will be directly
recharg~d back into the contaminated area without biological treat-
ment. The removal of the small remaining quantities of alcohols
and ketortes is neither necessary nor cost-effective for this stream.
The side: stream (of 50 gpm) will be treated using an extended
aeration, ~ctivated-sludge plant. Additional biological treatment
is necessary for the side stream because it is to be discharged
just outside of the slurry wall to induce ground water flow into
the containment area through the bedrock fractures. In addition
to enhanciny the water quality of the 'side stream, the additional
removal of alcohols and ketones will avoid any possibility of
damage to the outside of the slurry wall. The 50 gpm side stream
is adequately treated to protect public health and is discharged
on-site into less contaminated ground water just outside the slurry
wall.
Design of this plant is currently nearing completion and its
construction will be funded through an amendment to the Cooperative
Agreement. Capital costs of the plant are shown in Table l.
Estimated operational costs to complete the remedial action are

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TABLE 1
Vinyl Chloride
Benzene.
Chloroform .'
Jl,2-Tric~loroethane
'Ethylene Chloride
Tetrachloroethylene
Tricnloroethylene
Xylenes
Methyl Isobutyl Ketone
Methyl Ethyl Ketone
Chlorobenzene .
Methylene Chloride'/
Toluene
Ethyl Benzene
1,1-Dichloroethane
t-l,2-Dichloroethane.
l,l,l-Trichloroethane
Methyl Methacrylate
Ethyl Chloride
Tetrahydrofuran
2-Butanol
Dimethyl Sulfide
Diethyl Ether
Methyl Acetate
Isopropyl Alchol
Acetone
: \
HIGHEST CONC. .
fUUND IN
GROUND WATER
(PPB) .
950
3,400
31,000
17
73,000
570
15,000
10,000
21,000
80,000
1,100
122,500
29,000
1,200
lS
18,000
2,000
3,500
320
1,500,000
3,560
3,500
20,000
2,400
26,000

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TABLE 2
ESTIMATED CONSTRUCTION COSTS
-
ITEM
CAPITAL COST:
1.
:onstruction of treatment building,
site work, utilities, and sludge disposal site
985,000
$
2.
Chemical precipitation, neutralizaton,
sludge de~atering
635,000
3.
High temperature air stripping, incineration,
and compliance testing
622,OQO
4.
Extraction and recharge system

package: extended-aerati~n, activated-sludge
plant with nutrient addition to treat
purge stream
475,000
5.
340,000,
6.
Electrical, instrumentation, piping, and RVAC
857,000
Subtotal
$ 3,914,000
7.
Contingencies (20%)
782,400
Total Capital Cost

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ITEM
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1. Labor
2. Electricity
3. Fuel Oil
4. Chemicals
TABLE 3
ESTIMATED ANNUAL OPERATIONAL COSTS
TO COMPLETE THE REMEDIAL ACTION
5. Sludge Disposal (on-site)
6. Maintenance Materials
7. Miscellaneous (Insurance, Phones, etc.)
TOTAL
COST
$262,200
69,000
883,000
96,800
41,400
13,800
13,800

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LOCATION MAP
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HUDSON
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.
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NEW ItAMPSltlRE
MASSACItUSETTS
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NEW
HAMPSHIRE

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Re I lIa:tarrlous Waste Site IlIvcstigation
Sylvester Site. Gilson Road, Nashua, New
Hampshire, GIIR Engineering Corp/GZA. Inc.
1981
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Trailer P.rk
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TIlE AREA SURROUNDING TilE SYLVESTER SITE
(NOT TO SCA 1.1:)
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DA TE:
SUBJECT:
FROM:
u.s. ENVIRONMENTAL PROTECTION AGENCY
REGION I
September 22, 1983
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Transmittal of Alternate Concentration Limits for the
Gilson Road Site, Nashua, NH Site
TO:
Michael R. Deland, Regional Administrator, Region I

Lee M. Thomas, Assistant Administrator for Solid Waste
and Emergency Response (WH-562-A) EPA, Washington, DC
I am transmitting to you al~ernate concentration limits
for the Gilson Road site which I believe have complete
technical support. I would like to potnt out that a
comprehensive legal and programmatic review has not been:
initiated in the Region. It is my understanding that
the issues concerning the interface with CERCLA and RCRA
is currently under consideration in Washington and we

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OATE
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
September 21, 1983
. SUBJECT
Recommended Alternate Concentration Li~its for the Gilson Road
Site, Nashua, NE.
F~OM
Michael R. Deland, Regional Administrator
EPA, Region I, Bostc~, MA
-. TO
Lee M. Thomas, Assistant Administrator for Solid Waste
and Emergenc~ Response (WH-562-A)
EPA, Washington, DC.
Introduction.
I. am recommending to you alternate concentration limits for the
Gilson Road site, which I have determined to be compatible with
the RCRA regulations described in the July 26, 1982 Federal Register
Section 264.92 through 264.94. This determination should assist
you in approving the Record of Decision dated September 22, 1983
currently awaiting your signature.

Backc;round
The Gilson Road hazardous waste site located in Nashua,
New Hampshire has received remedial action under the
Comprehensive Emergency Response, Compensation, and Liability
Act (CERCLA) since November, 1981. EPA used CERCLA emergency
funds to install a ground water interception and recirculation
system. This system was operated until October, 1982 when a slurry
wall was completed. The State of New Hampshire developed a
remedial investigation and feasibi1i"ty study in January, 1982 and
a s~pplemental study providing costs associated with various ground
water treatment rates in July, 1982. A Record of Decision was
signed by the AA, OSWER in July, 1982 which approved the
installation of the slurry wall and pilot studies.

Upon completion of the slurry wall, a pilot treatment plant was
constructed and operated for several months. The data from this
pilot study resu~ted in a recommendation to construct a treatment
plant capable of removin9.~0% of the hazardous constituents within
the slurry wall. This design was based on evaluating the present
and potential hazards to human health and environmental targets
previously identified in the risk assessment portion of the
feasibility study and supplement. A subsequent design modified
to reduce operation and maintenance costs, but still capable of
90% removal is presently the subject of a Record of Decison dated
September 22, 1983 awaiting signature by the AA OSWER. A
briefing for the Director OSWER prior to the briefing for the AA
OSWER su~faced the issue that a CERCLA financed ground-water
treatment system should significantly reduce the level of
ground-water contamination and in conjuction with the containment
structure should be compatible with RCRA regulations g~verning
ground water protection.

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-2-
Present Situation
At this site, there are 16 hazardous constituents in the ground-
water which are identified in Appendix VIII of RCRA Part .261.
These hazardous constituents will be treated by the treatment
process and reduced in concentration by an order of magnitude.
(See Table 1). For these hazardous constituents, I am
recommending the a~t~rnate concentration limits set forth in
Table 1. These alternate concentration limits are consistent
with the treatment design rationale which was set forth in the
Feasibility Study of May, 1982 and approved in a subsequent
Record of decision. These A.C.~.'~ were derived from extensive
technical research into the potential hazard posed by such
concentrations to the human population at risk (residents a~ two
adjacent mobile home parks) and to environmental targets identified
during the risk assessment, namely Lyle Reed Brook and the Nashua
River. The documents which contain the technical rationale for
establishing these limits and the equivalant requirements as
specified in 264.94. of the RCRA regulations are enumerated in
Appendix A.
Public Participation

The NH Water Supply and Pollution Control Association actively
solicited public participation and input into the decision process
in establishing the alternate concentration limits. Two formal
meetings were held: one in March, 1982 and another in August, 1982
to present the findings of the remedial investigation and "feasibility
study and to describe the various treatment schemes and results of
the pilot plant study. The public reaction to the proposed treatment
scheme was highly favorable including public acceptance of the
long term effect of the contaminant containment and treatment. In
addition, the public was made aware of all pertinent issues and
the progress of remedial action through press releases, press
conferences, and various mailings. At this time" the public is
urging rapid implementation of the chosen alternative.
Recommendation
I am recommending that these site specific alternate concentration
limits set forth in this memo be accepted as compatible with the
RCRA regulations and guidance governing ground water protection.
These limits represent a conservative evaluation of the concentration
of contaminants which may remain within the slurry wall after
treatment. In actuality, the slurry wall is expected to achieve
30 to 70% reduction after treatment. The contaminants which may
leave containment would leave from the lower portion of the
aquifer and this will provide additional attenuation to protect
~yle Reed Brook. Alternate water supplies have been provided to
the human population at risk, and the assimilative capacity of
the Nashua River will further protect downstream users should
the treated contaminants migrate downstream. All these
safeguards further protect public health and the environment
beyond the inherent protection derived from the treatment

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.
Table I
Contaminated Concentration Within the Containment
After Treatment
Appendix VIII
Hazardous Constituents
-
Vinyl Chloride
Benzene
Chloroform ,
1,1,2 trichloroethane
Tetrachloroe~hylene
Trichloroethylene
Methyl Ethyl Ketone
Chlorobenzene
Methylene Chloride
Toluene
1,1 Dichloroethane
trans-l,2-Dichloroethane
1,1,1 Trichloroethane'
Methyl Methacrylate
Selenium
Phenols
Recommended A.C.L. Within
the Containment Structure
95 ug/l
340 ug/l
1505 ug/l
1. 7 ug/1
57 ug/l
1500 ug/1
8000 ug/l
110 ug/1
1:2250 ug/l
2900 ug/l
1. 5 ug/l
1800 ug/1 .
200 ug/l
350 ug/l
2.6 ug/l
400 ug/l

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Appendix A
RCRA Requirement
in Developing A.C.L.'s
The physical and chemical characteristics
of the waste in the regulated unit, including
its potential for , migration;

The hydrogeologicar~haracceristics of che
facility and sur~ounding land:
The quanity of ground water and the direction
of ground water flow;
The p~oximity and wichdrawal rates of ground-users;

The current and future uses of ground water
in che area. '.
" .
The existing quality of g~ound water, icluding
other ~ources of contamination and their cumulation
impact on the g~ound-water quality;

The potential fo~ health ~isks caused by human
. .
exposure to waste consltutents:
The potential damage to wildlife, crops, vegatation,
and physical structures casued by exposure to waste
consituents:
The persistance and permanence of che potential
adverse effects of hydraulically-connected
surface-water quality considering;

The volume and physical and chemical
characteristics of the waste i~ the
regulated unit:
The hydrogeological characteristics of the
facility and surrounding land~
The quanity and quality of ground water, and
the direction of ground water flow;
The patterns of rainfall ~n the region~

The proximity of the regulated unit to
surface waters:
Technical
Documentation
(1)(2)(4)
(1) (2)
(1)(2)(4)
(1)(2)
(1)(2)
(1)(2)
(1)(2)
(1)(2)
(1)( 2)
(1}(2)(4)
(1)(2)
(1)(2)(4)
( 2 )

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Appendix A
Con t .
RCRA Requirement
in Develo~ina A.C.L.'s
Technical
Documentation
The current and future uses of surface
waters in the area and any water quality
standards established for those surface
waters~
(l) ( 2)
The existing quality of surface water,
including other sources of cantamina~ian and
the cumulative impact of surface-water quality
(1)(2)
The potential health_~isk causesd by human
exposure to waste-constituents;
(1) (2)
The potential damage to wildlife, crops.
vegetation, and physical structures caused
by exposure to waste constituents;
(1)(2)
The persistence and permanance of the potential
adverse effects.
(1) (2)
Key
Contained in the following Documents:
1. Remedial Investigation (GHR Report)
2. Final Report. Sylvester Hazardous Waste Dump site Containment
and Cleanup.

3. Supplemental report to final report.
4. Gilson Road Hazardous W~ste site pilot plant treatment

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