Superfund Record of Decision: Tinkham Garage, NH


United States
Environmental Protection
Agency
                       Office of
                       Emergency and
                       Remedial Response
EPA/ROD/R01 -96/016
September! 986
F PA
Superfund
Record of Decision

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TECHNICAL REPORT DATA
(Pleale read Inttructionl on the revene /Hlore completing)
1. REPORT NO. \2. 3. RECIPIENT'S ACCESSION NO.
EPA/ROD/RO 1-86/016
.. TITLE AND SUBTITLE 5. REPORT DATE
SUPERFUND RECORD OF DECISION September 30, 1986
Tinkham Garage, NH 6. PERFORMING ORGANIZATION CODE
7. AuTHORCS) 8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT NO.
". CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS 13. TYPE OF REPORT AND PERIOD COVERED
U. S. Environmental Protection Agency Final ROD RePOr t
401 M Street, S.W. 1.. SPONSORING AGENCY CODE
Wash ington, D.C. 204 60 800/00
15. SUPPLEMENTARY NOTES
16. ABSTRACT .
The Tinkham Garage site encompasses 375 acres of residential and undeveloped land in
Londonder ry, NH. Approximately 400 people reside within a condominium complex on.the
western boundary of the site. Additional housing includes pr ivate, one-family homes
with in site boundar ies to the nor th. An unnamed tributary and an attached intermittent
stream branch thr ou gh the condominium complex and discharge in to Beaver Br ook, wh i ch
discharges to the Merr imack River fur ther sou th . The 100-year flood plain forms an
approximately 2-acre wetland at the tributary's confluence with Beaver Br ook . The flood
plain widens considerably south of the complex forming a 66-acre wetland. In addition,
a 57-acre wetland exists to the southeast of the site. Some residents within the site
continue to use the bedrock aquifer for dr ink ing water purposes. Ground water in the
bedrock discharges to the tributary via surface and ground migration. Be tween 1978 and
1979, waste disposal activities behind Tinkham garage included the direct surface
dumping of liquids and sludge from tank truck washings. In Apr 11 1978 citizen
complaints of foam and odor s in a small unnamed brook resulted in a site cleanup and the
excavation of a diversion tr en ch to direct surface run-off. The RI, completed in
January 1986, documented contamination from volatile and extractable organic compounds
associated with ground water in overburden and bedrock aquifers, sur face water and in
soil located in the field behind Tinkham garage and in the condominium complex.
(See Attached Sheet)
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS b.IDENTIFIERS/OPEN ENDED TERMS C. COSA TI Field/Group
Record of Decision
Tinkham Garage, NH
Contaminated Media: gw, sw, soils, sediment~
wetlands, wood
Key contaminants: VOCs, or gan ics, sludge, mE tals
PCBs, TCE
1B. DISTRIBUTION STATEMENT 19. SECURITY CLASS (Tllis RepoNI 21. NO. OF PAGES
None 126
20. SECuRITY CLASS (TiJiS pagel 22. PRICE
None
EPA '0,",2220-1 (R... 4-77)

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EPA/ROD/ROl-86/016
Tinkham Garage, NH
16.
ABSTRACT (continued)
Specifically, contaminated soil within the complex was associated with the
individual domestic waste leaching fields for a number of buildings within
the complex. Two other source areas existed within the complex: a refuse
area for disposal of soils excavated from the leach fields; and a low lying
contaminated swale area in close proximity to the unnamed tributary. The
swale is suspected to be another site of direct discharge of liquid wastes
to the ground surface. The primary contaminants of concern include: VOCs,
organic sludges and metals.
The selected remedial action includes: excavation of approximately
10,800 cubic yards of contaminated soils behind Tinkham garage; field work
and analytical modeling to determine the need for the removal of additional,
potentially contaminated soils in the condominium complex; onsite treatment
of all excavated contaminated soils by either aeration, composting or soil
washing; regrading and revegetation of excavated source areas after treated
soils have been returned to their original locations; reconstruction of any
removed leach fields; restoration of wetlands where contaminated soils are
excavated; extraction and offsite treatment of contaminated groundwater at
Derry, NH publicly owned waste water treatment works, which may lead to
offsite pretreatment; ground water monitoring onsite and offsite. The

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~EC(JRD OF DEC"::SION
RE~EDIAL ALTERN~TIVE SP,LECTION
SITE:
Tinkham Garage, Lonrlonderry, New Hampshire
I am basing my decision primarily on the following documents
describing the analysis of cost-effectiveness of remedial
alternatives for the Tinkham Garage site:
DOCUMENTS REVIEWED
1.
Field Investigation Report for the Tinkham Garage site,
Londonrlerry, New Hampshire, March 7, 1984, prepared for U.s.
EPA, Region" I, by NUS Corporation, Bedford, Ma~sachusetts.
2.
Remedial Investigation for the Tinkham Garage site, Londonderry
New Hampshire, January 15, 1986, prepared for U.S. EPA, Region
I, by NUS Corporation, Redford, Massachusetts.
3.
Endangerment Assessment for the Tinkham Garage site, Londonderry
New HampshirA, May 7, 1986, prepared for U.s. EPA, Region I,
by NUS Corporation, Bedford, Massachusetts.
4.
Feasibility Study for the Tinkham Garage site, Londonderry, New
Hampshire, July 31, 1986, prepared for U.s. EPA, Region I, by
Camp Dresser & McKee Incorporated, Boston, Massachusetts.
5.
Technical memorandum: Water Level Measurements - Tinkham
Garage Site and Ross Drive, July 14, 1986, prepared by U.S. EPA,
Region I, staff.
6 .
Summary of Remedial Alternative Selection (attached).
7.
Community Relations Responsiveness Summary (attached).
8 .
The National Oil and Hazardous Substances Pollution Contin~ency
Plan, 40 C.F.R. Part 300.
DESCRIPTION OF SELECTED REMEDY
- Excavation of approximately lO,ROO cubic yards of contaminated
soils behind Tinkhams' garage.
- Field work and analytical modeling to determine the need for
the removal of additional, potentially contaminated soils
in the Woodland Village Condominium complex.
- Onsite treatment of all excavated contaminated soils by
either aeration, composting or soil washing.
- Regrading and revegation of excavaterl source areas aEter

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- Reconstruction of any re~overl leachfields.
- Restoration of wetlands wh8re conta~inated soils are excavated.
- Extraction and offsite treatment of contaminated groundwater
at the Town of Derry, New Hampshire publicly owned wastewater
treatment wor~s, which may be preceded by onsite pretreatment.
- Groundwater monitoring onsite and offsit~.
OPERATION AND MAINTENANCE
Operation and maintenance (O&M) will he a necessary component of the
long term onsite and offsite monitoring which is to include sampling
and analysis. The sampling and analysis will he required to monitor
the water quality of residential wells in use on artd off site.
DECLARATIONS
Consistent with the Comprehensive Environmental Response, Compen-
sation, and Liahility Act of 1980 (CERCLA), and the National
Contingency Plan (40 CFR Part 300), I have determined that the
excavation and onsite treatment of contaminated soils and the
extraction of contaminated groundwater with offsite treatment at
the Town of Derry, New Hampshire publicly owned treatment works
is a cost-effective remedy and provides adequate protection of
public health and welfare and the environment at the Tinkham
Garage site. The groundwater pumping and treatment program will
be considered part of the approved ~ction and eligihle for Trust
Fund monies for the time period necessary to attain target levels,
not to exceed 5 years. In addition, the remedy will require
future operation and maintenance activities to monitor the water
quality of residential wells on site and off site. These activities
are eligihle for Trust Fund monies for a period of 1 year. The
State of New Hampshire has heen consulted and agrees with the
approved remedy.
I have also oet8rmineo that the action heing taken is appropriate
when halanced against the av~ilability of Trust Fund monies for
use at other sites.
5'~:-p_12=~~''''~_-:£~j_.l~
V Date
/7 . r~
_--L_r-LL~_~/. L(.~--.~
Michael R. Deland
Regional Administrator

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SUMMARY OF RE~~DIAL ALTERNATIVE SELECTION
TINKHAM GARAGE
Lonrlonderry, New Ha~pshire
SITE LOCATION AND DESCRIPTION
The Tinkham Garage Site encompasses 375 acres of residential and
undeveloped land situated in the southern New Hampshire Town of
Londonderry. As shown on Figure 1, the site is approximately one
mile southwest of the intersection of Interstate 93 and State
Route 102. It is bounded by State Route 102 to the north, Gilcreast
Road to the east, Ross Drive to tbe South and the Woodland Village
Condominium c01Tlplex to the west.
The site includes various developed areas. Approximately 400 people
reside within the recently converted Woodland Village Condominium
complex (formally Londonderry Green Apartments), which consists of
thirteen multi-unit buildings. Additional housing includes private,
one-family homes along Mercury and McAllister Drive within site
boundaries in the northern sector of the site, and along Gilcreast
and Ross Drive bordering the site. Tinkhan Realty Office and
Tinkham's garage are located in the northeastern sector of the site.
Undeveloped land fe3tures include wooded areas, open fields and wet-
lands. Topography of the site is relatively flat with surface drainage
from nortl) to south. An Unnamed Trihutary and an attached intermittent
stream branch through the condominium complex onsite and discharge
off site to Reaver Rrook south of Ross Drive. In turn, Reaver Rrook
discharges to the Merrimack River further to the south. The 100 year
floodplain on site extends from Route 102 and follows the Unnamed
Trihutary along to its confluence with Reaver Rrook. The floodplain
is generally 100 feet wide along its path through the condominium
complex. This area forms an approximately 2 acre wetland. Beyond
site boundaries, south of the condominium complex, and prior to
the trihutary's confluence with Reaver Brook, the floodplain widens
considerably forming a 66 acre wetland. In addition, to the south
of Tinkhalo's garage and forming the southeast corner of the site
exists a 57 acre wetland (see figure 2).
The primary source of drinking water to the site area, prior to the
installation of a permanent waterline, W3S the hedrock aquifer.
Residents along Gilcreast and Ross Orive as well as the Tinkham
Realty Company and one private home to the east of the realty
office continue to utilize this bedrock aquifer for drinking water
purposes. The groundwater flow in bedrock appears to take place
l~rgely in fracture zones which have a northeast/southwest
orientation. Groundwater in bedrock apparently discharges to the
Unnal'1ed Trihutary on site from both east and west of the tributary.
Additionally, there exist a nwober of flo\IIing bedr.-ock wells along
Mercury Drive and within the com~omini\lJ11 complex. Gr-ounrlwater
discharging to the surface from these w,~lls rnigrates to the Unnamed
Tributary via ground surface flow.

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SITE HISTORY
Initial co~plaints of foa~ and odors occuring in a small unnaned
brook crossing Ross Drive led the Londonderry Health Department to
the Tinkhan Garage site in April 1978. T~eir investigation conclu1ed
that liquids and sludge from tank truck washings had been dumped
behind Tinkham's garage directly to the ground surface. A subsequent
citizen co~plaint to the New Hampshire Water Supply and Pollution
Control Commission (NHWS&PCC) resulted in ordering a site cleanup
involving removal of surface contamination. Additionally, a
diversion trench was excavated to divert surface run-off from
behind the garage area away from Ross Drive. It is believed waste
disposal practices took place at the Tinkham site during the years
1978 and 1979.
u.S. Environmental Protection Agency involvement with the Tinkham
site began in August 19R1 as the result of further 'citizen complaints.
A Preliminary Assessment identified groundwater used as a potable
water supply, as well as soil and surface water, was contaminated
by volatile organic compounds. In January 1983, the drinking water
supply well servicing Londonderry Green Apartments (presently
~~oodland Village Condominiums) and residential wells along Mercury
and McAllister Drive were taken out of service because of documented
or potential organic contamination. The U.S.EPA temporarily supplied
water until a permanent water line was installed by the NHWS&PCC
under a cooperative agreement between the State and the U.S.E?A in
November 1983.
The Tinkham Garage site was proposed for inclusion on the National
Priorities List (NPL) in December 19B2, and finalized in September
1983. A Remedial Investigation was begun in the Spring of 1984
and completed in January 19B6. The investigation documented
contamination from volatile and extractable organic compounds
associated with groundwater in overhurden and bedrock aquifers,
surface water and in soil located in the field behind Tinkham's
garage and in the Woodland Village Condominium Complex. Specifically,
contaminated soil within the condominium complex was associated
with the individual domestic waste leaching fields for a number of
buildings within the complex. In addition, there existed two
other source areas in the condominium complex. The first source
area was a refuse area utilized by the condominium complex and
used to dispose of soils excavated from the leachfields. The
s8cond source area was a low lying contaminated swale area hehind
condorninium buildings E and F and in close proximity to the Unnamed
Trihutary. The swale is suspected to be another site of direct
dicharge of liquid wastes to the ground surface.
,<
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CURRf\T SITE STATUS
The results of the Field Investigation (PI), Re~edial Investigation
(RI) and arlditional field work conducted during the preparation of
t~e Feasihility Study (FS) identified and verified four distinct
conta~inated soil source areas (see figure 3). Groundwater contami-
nation was found in both the overhurden and hedrock aquifers.
Sedi~ent and surface water contamination was found to he associated
with the Unnamed Tributary and its attached. intermittent stream as
well as in wetland areas onsite.
The four soil source areas are the field to the immediate south of
Tinkham's garage, the swale area, the soil pile and the domestic
waste leaching fields associated with the condominium complex.
- Field Rehind Tinkhams' Garage
The areal extent of the source area in the field behind the garage
is approximately 29,100 square feet. It is believed that sl~dge and
liquids containing metals and volatile and extractable organic
compounds were disposed directly to the ground surface at this loca-
tion. This is a low lying area and much of it is submerged beneath
water dur.ing the spring when the water table (which has a seasonally
low level of 5-10 feet below the ground surface) rises to the surface.
percolating groundwater is thought responsible for the gradual
leaching of surficial contamination to the hedrock aquifer through
the relatively permeable sand and the two, relatively low,
permeable till layers. The sand and two till layers form that
portion of the overburden aquifer behind Tinkham's garage. The
overburden and bedrock aquifers are hydraulically connected and
downward flow gradients have been noted in well clusters in this
source area.
A wide variety of volatile and extractable organics have been
documented in this soil source area. Additionally, sediments
associated with that portion of this source area that is wetlands
have also indicated contamination. It is anticipated that the
naturally high organic content of the soils and sediments is re-
sponsible for attenuating much of the residual contamination. It
is likely that the contaminated overburden provides a continuing
source which may leach to the bedrock aquifer.
- Woodland Village Condominium Leachfields
There are thirteen leachfields, lettered A through G and I through N,
which provide for domestic waste disposal from the corresponding
condominium buildings. These leachfields are underlain by a veneer
of sandy oVArhurden of a variable thickness which overlies the
fractured bedrock aquifer. This aqllifer served as the primary drinking
water source prior to contamination. In the past, several of these
systems failed for lJnexplained reasons and were replaced. Additionally,
all of the remaining leachfields were repaired or replaced in lqR3/1qR4.
It is believed that all leachfields were repaired or replaced

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FIGURE 3

CONTAMINATED
AREAS

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after waste dispos31 activities ceased in 1979. Based on
analytical, hydrogeological and geophysical investigatio~s,
it ~ppears that only leachfields G, I/J, KIL, M/N and possihly A
continue to be source areas of volatile and extractable organic
contamination to the groundwater. However, because of EPA's under-
standing of the waste disposal practices at this site, and the
possibility of incomplete removal of contamination when these
leachfields were supposedly replaced, all leachfields are considered
suspected source areas. Conservatively, the entire volume of any
contaninated leachfie11 is considered to be the extent of that
particular source area. Each leachfield has a lateral surface
area of either 5,400 or 7,700 square feet, and a depth from 5 to 10
feet.
- Soil Pile
Soil removed from each replaced leachfieln after the introduction
of contaminants was buried on the grounds of the condominium complex
in a refuse area behind buildings C and D.
Analysis of the soil pile contents is considered indicative of
what was discharged to the le~chfields and what remaining or
residual contaminants most likely exist within the leachfields.
The pile has a lateral surface area of 1,ROO square feet, with an
average depth to groundwater of 5 feet. It is only slightly elevated,
approximately 2 feet ahove the surrounding ground elevation.
Au~ering revealen a 1 to 2 foot layer of clean fill overlying a
plastic cover. The plastic cover and clean fill were placed over
the contaminated soil by the owner of the then apartment complex at
the request of the NHWS&PCC and EPA in May 1984.
-Swale
The Swale is a low lying area adjacent to the Unnamed Tributary,
hehind and close to condornimium buildings E and F. According to
field screening it is composed of two separate areas, one 120 feet
by 30 feet and the other 100 ft by 20 feet. Depth to groundwater is
approxim"1tely 5 feet. This area was covered over with approximately
2 feet of clean fill in 1982. (All docu!'1ented or potential soil
source aeeas are summarized in Table 1).
- Groundwater (overburden and bedrock)
Overhurnen groundwater flow over the entire site is migrating
towards the south/southeast. Behind the garage, overburden ground-
water can potentially disch~rge to the surrounding wetland or,
influenced by downward gradients, migrate into the underlying
bedrock. Once the contaminants enter the fractured hedroc~ aquifer,
they mi'Jrate in a direction which is approximately perpendicular
to the flow in overhurden.

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TABLE 1
Soil Source Areas
 Latera 1 ~urface Vertical Vol~me
Source Area Location Area (ft ) Extent (ft) (yd)
Southwestern Section of   
a field in back of the   
Tinkham Garage 29,100 10 10,777
Leachfield A 2,500 10 900
Leachfield B 2,500 10 900
Leachfield C/O 7,700 10 2,900
Leachfield E/F 7,700 10 2,900
Leachfield G 5,400 5 1,000
Leachfield I/J 7,700 10 2,900
Leachfield K/L 7,700 10 2,900
Leachfield M/N 7,700 10 2,900
Solvent Swale 5,600 5 1 ,000
Soi 1 Pil e 1,800 5 700

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D~ta gathe~ed f~om two pump tests have inrlicated that the flow in
the bed~ock aquife~ is prim~rily controlled by the alignment of
onsite wate~ bearing fractu~e sets which a~e o~iented
northeast/southwest (see figure 4). During the first pump test,
well LGSW that was used for a water supply for the condominium
complex was pUMped. This created a trough of drawdown extending
parallel to Me~cury Drive to the source area in the field behind
Tinkham's garage. This indicates that the condominium complex
supply well once used for drinking water is hydraulically
connected to the source area behind the garage.
Volatile o~ganic compounds, extractable organic compounds and
metals have been identified in groundwater. Levels of total
volatile organics have inc~eased throughout the sampling history
of the wells on Mercury Drive. This indicates cont~minated groundwater
continues to migrate from the garage area toward residential wells.
Groundwater continuing to migrate from the source area behind
Tinkham's garage in fractured bedrock discharges to either the Unnamed
Trihuta~y, or to the ground surface through a number of flowing
wells along its path (See Figure 5). The discharge of groundwater
from the fractu~ed bedrock aquifer to the Unnamed Tributary is
suhstantiated by the presence of upward vertical gradients in
wells in this area.
A second pump test was conducted using well LGAW within the condominium
complex. This test indicated a second trough of depression running
parallel to the first and also indicated an inter.connection of
wells within and surrounding the complex.
As indicated, groundwate~ movement in fractured bedrock has been
shown to move preferentially in a northeast/southwest direction.
However, some groundwater movement can also take place perpendicular
to the main fractu~e sets within seconda~y f~actur.es. Groundwater
movement in seconda~y f~actures coupled with the f~ct that the
Tinkham Garage site is topographically and hydraulically higher
than many of the domestic wells in service along Ross Drive, suggests
that there is a potential for movement of contaminated g~oundwater
to these wells. A comparison of water level elevations in overburden
and bedrock monitoring wells on site and domestic bedrock wells
along Ross Drive confirms this potential.
It is suspected that contaminants originating from the leachfields
of the complex are transported along with the groundwater through
the thin overbu~den into the bedrock and migrate toward the Unnamed
T~ihutary. Groundwater can discharge to the surface along the way
th~ough a numher of flowing wells.
Monitoring wells in the vicinity of the 50il pile do not indicate
contaminated groundwater to be present. However, wells in this
vicinity do show downward vertical gradients, so that the soil pile
is considered a potential source of contamination to g~oundwater.

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FIGURE 4

DRAWDOWN ~INO f'lM>tNG
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TINKHAM GARAGE SITE
LONDONDERRY, NEW HAMPSHIRE
FIGURE 5"

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;s ~reviously stated, t~e Swale is in close proximity to the
Unna~erl Tri~utary and is located within t~e Inn year flood plain.
During periods of high flow in the tributary this area can flood,
providing a potential source of cootamination to the Unnamed Trih1ltary.
Risk Assessment
Volatile organic compounds constitute the predominant contaminants
at the Tinkham Garage site. These co~pounds also present the
major risk to public health and welfare and the environment at the
site. All contaminants of concern in groundwater identified at
the Tinkham Garage site are volatile organic compounds. Some
of these compounds are either known human carcinogens or probable
human carcinogens. Extractable organic compounds and metals have
also been identified. These contaminants have been documented in
one or more environmental media onsite.
-Groundwater
The greatest potential risk presented by the Tinkham site is from
contaminated groundwater. Groundwater from the fractured bedrock
served as the primary source of drinking water prior to 19R3 when
use of wells onsite were discontinued and an alternate water supply
was provided. Groundwater is contaminated by volatile organic
compounds, extractable organic compounds and metals. As indicated
above, the volatile organic compounds constitute the predominant
contaminants. The plume of total volatile organic contaminants
are dispersed across much of the site.
Tahle 2 indicates the contaminants of concern and a historical range
of these contaminants identified in groundwater. Table 3 indicates
the upper-limit lifetime cancer risk estimates attributed to these
contaminants. As can be seen, contaminants range from approximately
1 ppb to 0,700 ppb of volatile organic compounds. Furthermore,
based on historical exposure data from residential wells, the upper-
limit lifetime cancer risk has been cumulatively estimated at
3xIO-4. Rased on environmental monitoring well data it is estimated
at 2xIO-2. As a result of this contamination, the bedrock aquifer
that served as a water supply for approximately 450 innividuals in
the rapidly rleveloping, high growth area of Londonderry, is contam-
inated and undrinkable within site houndaries.
The provisions made in January 1983 to provide residents onsite with
an alternative water supply significantly reduced the potential for
exposure from contaminated groundwater. However, the exposure
potential still remains through the discharge of groundwater to the
around surface in flowing wells onsite, and through the use of private
r~sidential wells drawing on this aquifer which remain in service.
As indicated, the potential exists for groundwater to migrate to
residential wells in use along Ross Drive to the immediate south
of site boundaries. (These wells are currently unaffected). Furthermnre,
this area is one of high Qrowth and developement and the possihilit
exists (or future constnlction on site and the subsequent use of
this aquifer Eor drinking w~ter.

-------
TAW'
OVERVIEW OF CONTI\Ml. IT CONCENTRATIONS
GROUNDWATER CONTAMINANTS OF CONCERN
TINKHAM'S GARAGE SITE
Re~idential Supply Wells
Monitorillg WI""
Historical Range
(ppb)
Oate of Highest
Concentration
Historical Range
(ppb)
()ate of Ilif.hnt
C:onn"'lt r.t t it III
VOLATILE ORGANIC COMPOUNDS     
I\rlllll.ttic Hydrocarbons     
[\enZl'lle  1.2-8.5 12/82  2-120 (,- 7/ S ~
E t" Y I hCllzcne 2.-8.8 12/82  2-1,400 I2IM-I/R')
Toluelle  2-14 3/83  2-6,000 I 2/'1,1, - I / R ')
X ylelle~ (all i~orners) 1.5-21 3/83  10-2,200 12/84-11'1.5
Chlorinated Hydrocarbons     
     .'" 
Chlorufnrrn  1-13 2/83  5-34 6-7/83
I,I-nic:hloruethane 2-20 8/83  2-1,200 6-7/83
1,2-Dichloroeth.tne 2-10 2/83  2-400 6- ~ / 8 3
Tr .tl\~- I, 2-nichJoruethylene 2-23 1183  2.J-6,728 l/~ 1
T et r dchloruet hy I ene 2-7 8/83  4-91 12/'1.11- 1/8 ')
1, 1,1- Trichloruethiine 1-22 2-3/83  2-1,250 1/'1. 1
Tr ichloruet hylelle 2-180 8/83  4-450 12/811- 1/8 ')
Vinyl Chloride not indentified N/A  14- 2 30 6-7/S3
II iJ IUlllet hanes     
Methylene Chloride 2-290 2/83  2-78 6- 7/8 3
K ctolles      
I\Cf"tlllle  2-6 }OO 1/83  2-5,700 (...7/'1.)
  ,

-------
TARLE 3
UPPER-LIMIT CANCER RISK F.5T1MA TES
INGESTION or CaNT I\MINA TEn GROtlNn\\' 1\ TER
Carcinogenic
Potency
Factor i)
(mg/kg/dayr I
Maximum
Concentration
Detected
in Residential
Supply Wells
(ppb)
Maximum
Conrentrdtion
netected in
Monitoring Wells
(ppb)
(jt'n zene
0,045
0,070
0.069
0.012
0.040

0.019
2.30
8.5
13
10
290
7

180
120

34

400
Chloroform
1,2-Dichloroethane
Methylene Chloride
T etr dchloroet hylene
T richloroet hy lene
78
91

450
230
.a
Vinyl Chloride
not identi fied
Cumulati ve Estimate
a
lJ.S. EPA, 1984
b Ba~ed on lOaximum concentration detected in residential supply wells

c Ba~ed on maximum concentrdtion detected in groundwater monitoring wells
tipper - Limi I Li f pI i file
CiUlcer R i~k Eo;timat('
Rased on
Historical
EXPO~\Ke
Dat.,
I x 10- 5
3)( 10-5
2x 10-5
I x 10-4
8 x 10-6
I x 10-"
not identified
) x I 0 - I,
ndo;pc! on
EnvirolmwIII.11
\1oni tor~f)h
nilld
2 x I 0 - "
7xJrf'
8 x Iff II
3 )( 10- ')
1 X 10-"
2 x I 0 -I,
2 x 10-2

-------
~s yet, no groundwater conta~i~ation in either overburden
has bpen documented beyond ~ite boundaries. However, well
to the south of the condominium complex does indicate low
of volatile organic compounds, and the full extent of the
this area is not known.
or bedrock
FW-l7
levels
plume in
-Soil
Soil contamination has heen documented in the field behind Tinkham's
garage, the soil pile, the swale and in a number of leachfields.
The primary harm presented by these contaminated soil source areas is
the result of their potential to further contribute to the contamina-
tion of the overburden and bedrock aquifers. These source areas
can potentially leach contaminants to the groundwater resulting in
further contamination of the aquifer. As previously stated, downward
vertical gradients have been documented in the Tinkham's garage area
and within the Woodland village condominium complex. This enhances
the ability of contaminants to migrate through the overburden and
into the fractured bedrock aquifer.
The contaminated soil source area in the field behind Tinkham's
garage presents the additional risk of direct contact/ingestion
of the contaminated media, especially to sensitive populations
such as children. The field hehind Tinkham's garage presents
a significant risk in this regard primarily because of the
concentrations of hazardous contaminants, and the presence of
these contaminants in surficial media. Contaminants of concern
identified within the Endangerment Assessment, which is based on
data collected during the Remedial Investi~ation, are shown in .
Table 4. Table 5 indicates the upper-limit lifetime cancer risk
estimates from ingestion. These contaminants present a worst-case
cancer risk estimate of lxln-3 and a more likely cancer risk
estimate of 5xlO-5.
As can- be seen in tables 4 and 5, Polychlorinated Biphenyls (PCAS)
were documented onsite. Ad~itionally, PCBs were identified during
the FS in contaminated soil behind the garage and in sediments
associated with the small pond/wetland of the intermittent stream
flowin~ into the Unnamed Tributary in the condominium complex.
Concentrations were found to he less than 1 part per million (ppm)
in the majoricy of samples. A maximum concentration of 15 ppm was
detected in one soil sample collected during the FS from behind
Tinkham's garage.
The contaminated leachfields, the soil pile and the swale area all
associated with the condominium complex are not considered to
present a significant direct contact/ingestion risk to puhlic
health and the environment. The soil pile and swale are covered
over with clean fill and contaminant concentrations do not
present a significant direct contact health threat, because of the
limited physical access to the contaminated areas. Contaminants
buried within the leachfields are covered by a cement cap and top
soil. However, as previously stated, the leachEields arA considered
to be a potentially significant source of past and possihle continuing

-------
TABLE 4
OVER VIE" OF CONTAMINANT CON CENTRA nONS
son. CONTAMINANTS OF CONCERN
TINKHAM-S GARAGE
  Maximum Mean
 l . a Concentration Concentration
 ocatJon (ppb) (ppb)
ArO:T1atic Hydrocarbons   
Chlorobenzene TG 3,600 1,803
1,2-Dichlorobenzene TG 40,000 40,000
Ethylbenzene TG 84,000 42,075
Toluene TG 190,000 95,215
Xylenes (all isomers) TG 350,000 175,290
Chlorinated Hydrocarbons    
1, 1,1- Trichloroethane TG 16,000 ' 8,007
Trichloroethylene TG 64,000  21,456
Tetrachloroethylene TG 200,000  57,86.5
  230  
Ketones
2-Butanone (\1EK)
TG
. 22,000
22,000
Po;ych!orina~ed Bii>''Jenyis
TG
957
957
a
TG =

-------
SOURCE AREAs TINKHAM'S CARAce FIELD-
TARLE 5

UPPER LIMIT CANCER RISK fSTiMA YES
INGESTION OF CONT AMINA TED SOIL
Carcinogenic Potencyb
Factor
(mg/kg/dayf I
Chlorobenzene
Tetrachloroethylene
Trichloroethylene
PCBs (total)
NOc

0.040
0.0 I 9
4.3396
Maximum
Concentration
(ppb)
Average
Concentration
(ppb)
3,600
200,000

64,000
9~7
1,803

57,86'
21,4'7
9'7
Cumulati ve Estimate =
a Average and maximum concentrations used to calculate lifetime average exposures are
those from sam;>ling conducted by NUS/FIT in March, 198'

b
U.S. EPA, 1984
Upper-limit Lifetime
Cancer Risk Estimate
Worst-Case
Scenar io
8 x 10-4
I x 10-4
9x 10-'
I x 10-3
More-likt'ly
Scenario
Jx IO-'~
6 x 10-(,
I x 10-~

-------
contn~ination to the gr~undwater. Rasen on volume and concp.ntratir
of conta~inants identifien to d~te, these leachfielrls are probahly
second only to the fielrl behind Tinkham's garage in their ahility
to be a continuing source of contamination to the overburrlen and
bedrock aquifers. The swale ~rea and soil pile are also considered
to be probable source areAS of continuing groundwater contamination.
Critical contaminants identified in the condominium complex area
(i.e. the leachfields) and in the soil pile, as identified within
the RI and EA, are shown in table 6. Screening results from the
swale area indicate soil contamination to be present. However,
specific contaminants have not been identified.
-Surface WAter and Sediments
Surface waters onsite consist of the Unnamed Tributary and the
attached intermittent stream, which flow through-the condominium
complex, and the wetland areas, all previously defined.
In the Unnamed Tributary and intermittent stream, volatile organic
compounds were detected in surface water. Additionally, extractable
organic compounrls and metals were detected in sediments. No
contaminants were documented in either the tributary or the stream
prior to entering the site north of Route 102. This indicates
source areas onsite are the contributing source of contamination
to these WAter bodies and the associated sediments.
Offsite, the Unnamed Tributary flows into Beaver Brook. Historic
sampling shows no contamination in the Brook.
Surface water and corresponding sediment samples were collected
in the wetlands associated with the field behind Tinkham's garage.
Volatile organic and extr.actable organic compounds were identified
in both surface water and sediments. This contamination is
attributed to the discharge of overburden groundwater flow to
this area.
Contaminants detected in onsite surface waters and associated
sedilnents do not pr8sent a signficant risk to puhlic health and
welfare and the environment. with time, r.emoval of the source
areas and groundwater treatment the low contaminant levels present
would be expected to decrease to nondetectable levels.

-------
TABLE 6
OVERVIEW OF CONTAMINANT CONCENTRATIONS
son.. CONT A.\UNANTS OF CONCERN
TINKHAM~GAKAGESnc
Locationa
Max.imum
Concentration
(ppb)
Mean
Concentration
(ppb)
Aromatjc Hydrxarbons
Chlorobenzene
WV
8
8
Ethylbenzene WV 1,700 897
Toluene WV 640 640
Xylenes (all isomers) WV 4,200. 2,175
, 
Chlorinated Hydrocarbons
1,1, I-Trichloroethane
Trichloroethylene
'JIV
3
3
Tefrachloroethylene
WV
SP
230
27
S8.3
27
~
Polychlorinated Biphenyls
'flV
SP
86
22.5
86
22.5
a
c.-v =
SP =
\1.'ood:a:lc Village Condvmin..ium Area

-------
~LTERNATIVE EVALUATION
-Remedial Objectives
According to 300.68(a)(l) of the NCP, the primary objective of an
appro~riate response is defined as being:
...consistent with permanent remedy to prevent or minimize
the release of hazardous substances or pollutants or contami-
nants so that they do not migrate to cause substantial danger
. to present or future public health or welfare or the environ~ent.
In general, such a response includes source control measures,
which address source areas of contamination, and management of
migration measures, which address media or areas that have been
impacted by the migration of contaminants away from source areas.
Consistent with the NCP, remedial response objectives have been set
forth at the Tinkham site for the four documented or potential
source areas (i.e. field behind Tinkham's garage, the leachfields,
swale and soil pile) and management of migration for groundwater.
-Source Control Objectives
The remedial response ohjectives for source control measures include:
1) preventing or mitigating further release of contaminants'to
surrounding environmental media; and 2) eliminating or minimizing the
threat posed to the public health, welfare, and environment from the
source area.
The first ohjective, preventing or mitigating further release of
contaminants to surrounding environmental media, entails addressing
the migration pathways affecting contaminated soil source areas at the
Tinkham Garage site. The primary migration pathway identified at
the Tinkham Garage site is the transport, via downward migration of
contaminants from the soil in all four documented or potential
source areas into the groundwater in the overburden and bedrock
aquifers. Therefore, the first source control objective is to clean
up contaminated soi1s to prevent or minimize the transport of soil
contamination into the groundwater through this pathway. This source
control ohjective complements the management of migration objectives
discussed below.
The second objective, eliminating or minimizing the threat posed to
the puhlic health and welfare and the environment from the source
areas themselves, entails addressing the exposure pathways, receptor
populations and levels of exposure associated with the four soil source
areas. Human health risks are the primary concern of this objective.
The Endangerment Assess~ent conducted at the Tinkham site addressed
risks associated with direct contact/ingestion of soil and groundwater.
Although the risks associated with ingesting the soil are of concern,
it has heen concluded that the likelihood for the continued release

-------
of contami~ants to the groundwater and the associated potential
human health risks fro~ rlrin~ing the water are of the greatest
concern to public health, welfare and the environ~ent. ~s such,
source areas will be remediated based on the first objective stated
above (i.e., prevention or mitigation of further release of
contaminants to the underlying bedrock aquifer). Direct contact/
ingestion risks are considered in selecting the appropriate extent of
re~ediation in the field behind Tinkham's garage.
Clean up levels in soil have been proposed which are intended to
provide a level of clean up which will minimize the potential for
further release to groundwater.
Tetrachloroethylene (?CE) and trichloroethylene (TCE) concentrations
in both soil source areas and in groundwater will be used as
indicator compounds for remediation. The characteristics which
qualify these two compounds to be used as indicator compounds at the
Tinkham site are:
o They may present major health risks to existing and potential
receptor populations
o They Occur in high concentrations onsite
o They occur in all media sampled
o They have lower vapor pressures and solubilities than other
frequently occurring contaminants such that their natural
transport away from source areas is slower than of the other
volatile organics
Remediation of soil source areas will be evaluated in terms of the
reduction in levels of PCE and TCE, with the underlying assumption
that treatment to target levels for these compounds will result in
non-hazardous levels of other contaminants.
Source control measures will address soil above the seasonal low water
table (the unsaturated zone) and management of migration responses
will address contamination in the saturated zone of the soils below
the seasonal low water table. This is based on the fact that data
from soil sampling efforts indicate that the highest levels of
contamination are in the unsaturated zone with a tenfold reduction
below the water table. A comparison of the Average concentration
of total volatile organics in the unsaturated zone above the seasonal
low water table versus the saturated zone suggests that the unsat\lrated
zone contains 70% of conta~inants by weight. It is anticipated
that contaminants which have leached from the unsaturated zone to
the saturated zone can be managed using groundwater remediation
measures (Management of Migration).
-~anaJement of Migration Objectives
The remedial response objectives for management of ~igration measures
include: 1) preventing or miti~ating further 'nigration of ~ontaminants
f

-------
beyond their current extent, and 2) eliminating or ~ini~izing the
threat posed to the public health, welfare and environment from the
current extent of contaminant migration.
The first objective, preventing or mitigating further migration of
contaminants beyond their current extent, entails addressing the migra-
tion pathways affecting contaminated groundwater on site. These path-
ways include: further transport within the bedrock aquifer via ground-
water flow through bedrock fractures (of special concern is transport
to residential wells along Ross Drive); surficial exposure of contami-
nated groundwater via the vertical upward component of groundwater
flow in artesian wells located on site (i.e. in the condominium
complex and along r1ercury Drive), and migration to surface water
via groundwater recharge to the Unnamed Tributary.
The second objective, eliminating or minimizing the threat posed
to the public health, welfare and the environment from the current
extent of contaminant migration, entails addressi~g the exposure
pathways, receptor populations and levels of exposure associated
with contaminated groundwater. Human health risks are the primary
concern.
For similiar reasons discussed under source control ohjectives, PCE
and TCE will also be used as a guide to remediating the groundwater.
The target level for groundwater remediation is 5 ppb for PCE and TCE.
The proposed maximum contaminant level (riCL) for TCE is 5 parts per.
billion (ppb), while the proposed MCL for PCE is not yet available.
(MCLs are standards developed under the Safe Drinking Water ~ct
(SDWA) for public water supplies. The standards are based on health
and technological and economic feasibility). The same clean up
approach can be taken for PCE as TCE since these two compounds have
similar weight of evidence for their car.cinogenicity, practical
quantification level and treatment efficiency. (Note: at this time
5 pph is the contract laboratory analytical detection limit for
both TCE and PCE). The Resource Conservation and Recovery Act
(RCRA) requires the setting of a groundwater protection level that
is protective of public health and the environment. The groundwater
protection standard must be set at background, MCLs or Alternate
Concentration Levels (ACLs). EP~ considers the setting of target
levels at proposed nCLs to be equivalent to ACLs.
The incremental lifetime cancer risk developed in the FS from ingestion
of TCE and PCE at 5 ppb each in groundwater is approximately q x In-~
assu1ning additivity. The actual risk from exposure to groundwater
contaminated with these two chemicals will depend on their relative
concentrations at point of monitoring. For remediation purposes, 5 ppb
for trichloroethylene and 5 ppb for tetrachloroethylene are target
levels to be achieved in the groundwater within the overburden and
hcdrock aquifers within every well on site.
Treatment to 5 ppb for PCE and TCE is expected to reduce other
compounds identified in groundwater to non-detectable levels.
However, in the unlikely event other compounds are at detectable
levels upon meeting the PCE and TCE target remedial ohjectives for
~roundwater it will be necessary to determine the overall risk
associated with all compounds detected.

-------
A det8rmination will he maje hy EPA upon achi8ving 5 pph of PCE and
TCE i~ Jrounrlwat8r as to whether the aquifer clean up has satisfied
remedial o~jectives and to assure that water quality is adequately
prGtective of the public health and welfare and the environment.
Technology Development and Screening
"~uidance of Feasibility Studies Under CERCLA" and the National (Iii
and Hazardous Suhstances Pollution Contingency Plan (NCP) 300.n8,(f)
sets forth the process by which rem8dial Actions are evaluated and
selected.
The development and screening procedure for the selection of an
alternative as specified in the FS Guidance ~'anual consists of a
six step process:
1 - Identify site problems and pathways of contamination
2 - Identify general response actions to meet clean up goals
3 - Identify and screen technologies applicable to wastes and
site conditions
4 - Development of alternatives for source control and management
of migration remedial actions
5 - Initial screening of alternatives
6 - Detailed analysis of alternatives
Field work detailed within both the RI and FS reports supply the
information necessary for step 1.
Steps 2 through 6 of the process were carried through the FS inde-
pendently for source control and management of migration responses.
The preferred alternative selected for the Tinkham site consists
of one source control alternative and one management of migration
alternative.
General response actions, identified as response categories within
the FS, are based on the findings of field work conducted. Technology
screening considers the waste-limiting (waste characteristics that
lionit the effectiveness or feasibility of a technology) and site-
limiting (site characteristics such as soil permeahility that preclude
the use of a technology) factors unique to the Tinkham site, and the
level of technical development for each technology. Chapter 3 of
the Feasihility Study report details this process.
Tahl~s 7 and 8 summarize the general response categories and the
applicahlA technology screening for source control and management
of mi0ration.
T0chnologies which emerged from this screening process were comhined
into source control and M~nayel~ent of migration altArnAtives. This
process is detailed in the second-half of Section 3 of the FS.

-------
TABLE 7
RU~~D!A~ TE:~';8LO:;Y TECH';IU..L
FOR SJJ~CE CO~TROL
SCR~ t:~; r ~G
R:~edial Technologies
t~p'icab'e for Consideration
fQr Source Control
R~~edial Technologies
Te:hnically Feasible
for Source Control
~i:J ACT! ON
~o ACT! ON
Sit e See u r i ty
Site Security
CO~;T AI ~i'~ENT
CO~iT AI N~'ENT
Capping
Per;~eabl e Cap
~:ul til a,,'ered Systans
Surficial Stabilization
Capping
Per;TIeable Cap
~'u, til a,,'ered Systsns
Surficial Stabilization
!~SITU TREATMENT
H~SITU TREATMENT
-.
Treat~ent Technolo;ies
(Biological, Chemical, Physical)
Trea~ent Technologies
( B i 01 09 i c a 1, C h an i c a 1. P hy sic a 1 )

Separation Technologies
Aeration
Soil Flushing
1~~~bil;zat;on Technologies
Ce,~ent and Silicate Based
Fixatives/Grouting
Ther~oset Fixatives/
Polperization
Vitrification
Artificial Ground Freezing
Insitu Heating
Separation Technologies
Aeration
Soil Flushing

Detcxification Technologies
AerQbic 8iode;radation
h~aEro~ic Digestion
Enzy~atic Degradation
Oxidation
Rejjction Dechlorination
~;eJtral ization
Hydrolysis (b~se-catalyzed)

-------
K~-~=i~' Te:h~olo;ies
A~plica~le for Consideration
f~r S~J!"ce CO:ltrol
?::t~nAL
E),ca,..ation
O';SITE STO~~GE
\.,'aste Pile
Stora;e Vault
Stora;e Bins
Storage Bags
Tank/Dru~ ~torage
OI:SITE TREf..7~ENT
Treat7,ent Technologies
(Siological. Che::i;cal. Physical)

!~~o~ilization Technologies
Ce~ent and Silicate Based
Fixatives/Grouting
Ther.7,)pl astics
Ther~~sets Fixatives/
Pol y;:-. e ri z a t ion
Surface ~acrcen:apsulation
"~sorbents
Vitrification
Se~aration Techno103ies
Dryin9 B~ds
Filtration
Pressure Filtration
C 1 ass i fie a t ion
Screens a"d Sieves
Classifiers
Fc~~erej f..ctiv!~ed Carbon
or ~~5in Addition
En;:;oration
S61Ye~t ~xtr!ction/Soil ~ashing
re:r,~~dcal Aeration
TASLE 7 (Continued)
F.ei.1edi al Te:hn::;1 o;i es .
Technically Feasible
for Source Control
REt'~8V AL
Exc an t i on
CIJSITE STORAGE
\.,'aste Pile
Storage Bins
CNSITE TREAT~ENT
Tre~~ent Technologies
(5;010gical. Che~ical. Physical>

Se~arat;on Technologies
Dry; ng Beds
Pressure Filtration
Evaporation
Solvent Extraction/Soil
Mechanical Aeration

-------
r:~~~jial iE:r.;,)lo;ies
h;~licc~le for Co;.sideration
f0r Sc.r:e Co;.trol
r=to~ifi:ation TE:hnolo~ies
h;.a:r~)ic Di;estion
Cc~~osting
La rldfu,;;i ng
Enzy~atic Degradation
O~ic:tion
Reduction
Dechlorination
I;eutral ization
Hydrolysis (base-catalyzed)
Rotary Ki1 n/Ce-":",ent Ki1 n
Incineration
Multiple Hearth Incineration
High T~;~;rature Fluid ~all
Infrared Incineration
C'; S IrE DISPOSAL
RCRA La~dfill
REt~rn to Excavation
C~FSITE T~~AT~[NT
R:RA Hazardous ~aste
Treat.7,€'r,t, Storage, and
o is;:: ~ s a 1 Fa c il i ty
St~)ilization/Fixation
In:ir,eration
C~FSITt DiSPOSAL
R:RA Landfill
TABLE 7 (Cor.tinued)
K:~.ej;al Tecr,:101o;ies
Technically Feasible'
for $oJrce Control
Detoxification Technologies
CO::1posting
Rotary Kiln/Ce~ent Kiln
Incir,eration
High Te~~erature Fluid ~all
Infrared Incineration
O';SITE D!SDOS.8J.
RCRA Landfill
Return to Excavation
CFFSITE TREAT~~NT
RCRA Hazardous ~aste
Treat.~ent, Storage, and
o i s p 0 s a 1 Fa c il ity
Stabilization/Fixation
Incineration
OFFSITE DIS~OSAL

-------
-....... - ....
,,...- - -
. -'.... - '-
F~I.E:::'.L E:.,h;~C~Y i~:~';:::'~ S::,~~\~:~::;
FC~, ~JJ,.Ht-:~~1[~n C~ M;G:,';ilO~~
~~~=:ial 7e:~~~1~;ies
~~~li::~le for Cc~si:=ration
f~r M!~~;=m=~t of Mi;~!~ion
~;J ~:TION
11; ;; i t:J ri n 9
C:.~T~: ~~~::NT
Slurry \.'~"s
G r ~ U t ~ all s
Sr,eet Pi1 ing
BlocK Dis~la:e~ent
6;tto~ Seal Gro~ting
r: ',' ~ P. S ION
Slurry \.'alls
GrQut ~al1s
Sr,eet Pi1ing
Gro~n~~~ter Interceptor
Trench
COLLECTION
GrO~~~~3ter Interceptor Trench
Collector ~ells
H;SlTU i~~:"7~~,::NT
jre:Ure~t Te:~~ologies
(aiolo;ical. Che::-,ical. Physical)
Se;aration Te:r.~ologies
Pre:ipitation/Coc;ulation/
Flocculation
Car~on hdsorrtion
Fer~ea~le E:O irea~.ent
:et:~ification ie:r.nolo;ies
~~rJ)i: Si0:e;~:d5tion
~~3e~~~ic Dicestion
Cdcation -
~,~:.J: t ion
'.eJtral i za~ion
~'. -.; '."'r-l .5" S (..~sc- ~~t..l Vzc"j)
-';j')~VJ -"'-"'.......-.,;'...U
E1e:tro1j'sis
F.~"7=:1 a1 Te:r.;\ol o;i es
ie:h~ically Feasible
For Mc~e;~~ent of Mi;ration
~o A:TlON
Monitoring
"'?
CCNTA:N~::NT
DIV::RSION
COLLECTION
Ground~ater Interceptor Trench
It; S lTU
T~[Ai~~NT
Trea~,ent Technologies
(Siolc~ical. Cr.e:;,ical. PhJ'sical)
Detoxification Technolo~ies
her~)ic Sio:e;ra:ation
.

-------
""'" 1'\;:. = ':"
'''''>.J_- V
F,;"";:ial Te:hnJlogies
~;~lication for Ccnsid;ration
fvr r,3n=;;~:nt of Mi.;ration
C~SlTE TREAT~ENT (Cont.)
High Rate
Extended Aeration
High Purity Oxygen
Sequencing Batch
PACT
Rotating Biological Disc
Landfarmin~/Spray Irrigation
Re=ir~ulat;on Systems
EnZjmatic Degradation
Oxidation'
Ultraviolet/Ozonation
Reduction
Neutralization
Hy d ro 1 y s is
Electrolysis
~et Air Oxidation
Supercritical ~ater
ONSITE DISPOSAL
~?DES Discharge to
Surface ~'ater
Spray Application/Trenching
GroJn~,,'ater Interceptor Trench/
See;age Basins and Ditches
Reinjection ~el1s
CFFSITE TREATMENT
Municipal ~astewater
Treat~ent Facility
RC~~ Hazardous Waste Trea~ent.
S tor a; e. and D i s p 0 sa 1 Fa c 11 i ty
ResoJrce Recovery
Bbsegradation
C~e7.ical Treat~ent
G~FSITE D!S~8SAL
-.- .----.-.----
~~JES Discharge to
S~rfc:e \o,'ater
~~~~ 1'011 In~~~tion
J.,.'- -r ~- I... ""'..
(:Ccn~~nJe~)
F,E~neji al Technol 09i es
Technically Feasible
for M=na9~~ent of Migration
Rotating Bio10igcal Disc
Rec i rcula t ion Sy stems
OtJSITE DISPOSAl
NPDES Discharge to
Surface Water
Groun~~'ater Interceptor Trench/
Seepage Basins and Ditches
OFFSITE TREAiMENT
Municipal Wastewater
Treat;;ent Facn ity
RCRA Hazardous Waste Treat~ent.
Storage. and Disposal Facility
Resource Recovery
Biodegradation
Ch~ical Trea~ent
CFFSITE DISPOSAL
N~8£S Discharge to

-------
i~,3~~ E
F:~rr,ed;al Te:h~olo3ies
A~~licat;on for Consideration
f~~ ~:~:;~~ent of Misration
P.~~JVA~ (PUMPIN:;)
Inje=tion/E~tra:tion ~ells
Ground~ater Interceptor Trench
ONSITE STORAGE

Tank/Drum Storage
Surface Impounct~ent
O~SITE TREATMENT
Treat~ent Technologies
(,iological. Chemi~al. Physical)
,
Separation'Technologies
Precipitation/Coagulation!
Flocculation
Sedi~entation/Clarification/
Gravity Thickening
C€:ntri fuga t f on
Filtration
Granular Filtration
Carbon Adsorption
Vapor and Liquid Phase
Contactors
Powdered Activated Carbon
Additi on
Ion Exchange
Sorptive Resins
Air Stripping
SteaTi'l Stripping
D i s t i " at f on
Dissolved Air Flotation
Freeze Crystallization
Solvent Extraction
Ccalescers
Mechanical Aeration
Reverse Osm:JS1s
Ul trafiltration
Electro::ialysis

Cetcx1fication Technologies
t~rated Lagoons/Ponds
tctf,ated Slud;e Reactor$
Co;:.entional
S~~p keration
Co~tact S:c~,l;zation
(COntin~E:~
P'~,edial Techn:Jlogies
Technically Feasible
for M=~,a;e,;nent of '.~igration
''I
REMOVAL (PUMPING)
Injection/Extraction Wells
Ground~ater Interceptor Trench
Of.JS ITE STORAGE
Tank/Drum Storage'
O~SITE TREATMENT
Treatment Technologies
(Biological. Chemical. Physical)

Separation Technologies
Precipitation/Coagu1ation!
Flocculation
Sedimentation/Clarification/
Gravity Thickening
Granular Filtration
Carbon Adsorption
Vapor and liquid Phase
Air Stripping
Steam Stripping
Detoxification Technologies
Activated Sludge Reactors
Extended Aeration

-------
Development of Alternatives and Initial Screening of Alternatives
Alternatives developp.d anrl considered for. initial screening ~t the
Tinkham site are:
SOurce Control
SC-l No Action (with fencing)
SC-2 Capping
SC-2A Permeable Cap.
SC-2B Surficial Stabifization
SC-2C RCRA Multilayered Cap
SC-3
Insitu TreatMent
SC-3A Insitu Aeration
SC-3R Soil Flushing
SC-4
Onsite Treatment
SC-4A
SC-4 R
SC-4C
SC-4 D
Aeration
Soil Hashing
Composting
Inciner~tion
SC-5
Onsite RCRA Lanrlfill
8C-6
Offsite Incineration
SC-7
Offsite RCRA Landfill
~anagement of Migration
r.1 0 ~1- 1
No Action (with monitoring)
~10r'1- 2
Insitu Biological Treatment
tlO~1- 3
Onsite Tr.eatment
~10r.1-3A
Air Stripping/Filtration/Carhon Arlsorption (Discharge
to stream)
~1()r1-3B
Air Stripping/Filtration/Carhon Arlsorption (Discharge
to !jroundwater)
~1m1-3C
Steam Stripping (Discharge to stream)
~mr1- 3 D
~ir Stripping/Riodey~arlation/Filtration/Carbon
Arisorption (Discharge to ~roundwater)

-------
1'10r'1-4
Offsite Treatment
~.101.1-4A
Offsite Treatment at RCRA TSD facility
r'lm1- 4 B
Offsite Treatment at POTH .(with Onsite Air Stripping)
Section 300.6a(f)(1) of the NCP requires that
it is both possible and appropriate, At least
shall he developed as part of the Feasibility
following catevories:
to the extent that
one remediAl nlternative
Study in each of the
o Alternatives for treatment or disposal at an offsite
facility as appropriate.
o Alternatives that attnin applicable or relevant and
appropriate Federal public health and environmental
requirements.
o As appropriate, alternatives that exceed applicahle or
relevant and appropriate Federal public health and
environmental requirements.
o ~s appropriate, alternatives that do not attain applicable
or relevant and appropriate Federnl puhlic health and
environmental requirements hut will reduce the likelihood
of present or future threat from hazardous substances and
that provide significant protection to public health and
welfare and the environment. This must include an alter-
native that closely approaches the level of protection
~rovided by applicable or relevant and appropriate require-
ments.
o No action alternative.
The source control alternatives which fall under the category of
disposal at an offsite facility as appropriate are:
o Disposal at an offsite site incineration fncility (SC-6)
o Disposal at an offsite landfill facility (SC-7)
The source control alternatives which fnll under the category of
attaining applicabl~ or relevant and ap~ropriate requirements are:
o Onsite treatment of contaminated soils (5C-4)
o Disposal at an offsite incineration fncility (5C-6)
o Disposal at an offsite landfill fAcility (5C-7)
The source control alternative which falls under the category of
exceeding the applicable or relevant and appropriate requirements
1S:
o. D i s po sa 1 a tan off sit e i n c i n era t ion L'l c i. 1 i t Y (S C - 6 )
1

-------
The source control alternatives which falls under the catetory of not
attaining applicable or relevAnt and appropriate requirements are:
o Permeable capping or RCRA multi-layered cap (SC-2)
The source control alternative whic~ falls under the category of
no action is SC-l.
The management of migration alternative which falls under the
category of disposal at an offsite facility is:
o Treatment at an offsite facility (MOM-4)
The r1anagement of J\1igration alternatives which fall under the
category of attaining applicable or relevant and appropriate
requirements are:
o Treatment at an offsite facility (MOM-4)
o Removal/extraction, soil flushing and onsite treatment
(~10M-3)
The management of migration alternative which falls under the
category of not attaining applicable or relevant and appropriate
requirements is:
o ins{tu biological treatment (MOM-2)
The management of migration alternative which falls under the
category of Non-action is MOM-I.
Consistent with screening criteria 300.68 (g){l) ,(2)and(3) of
the NCP, and as described in detail in Section 4 of the FS, the
initial screening process eliminated the following alternatives:
Source Control
SC-2
Capping
SC-2A
SC-2B
SC-2C
Permeable Cap
Surficial Stabilization
RCRA Multilayered Cap
- 300.08 (g){ 1); No substantially
and environmental benefits than
with greater costs
greater public health
the Non-action alternative
- 300.68 (g)(2); does not meet acceptable engineering
practices for reliability based on site characteristics
SC-3
Insitu Treatment
SC-3A
insitu aeration
- 300.68 (g) (3); adverse environmental impacts

-------
- 300.68 (g)(2); technically ineffective and not feasible
based on site characteristics
5C-4
Onsite Treat~ent
SC-4D
Onsite incineration
- 300.68 (g)(l); no suhstantially greater public health
and environmental benefits with $ignificantly greater
costs than other onsite treatment alternatives
SC-5
Onsite RCRA Landfill
- 300.68 (g)(3); adverse environmental impacts
- 300.68 (g)(2); does not meet acceptable engineering
practices for reliability and is not feasible based
on site characteristics
Management of Migration
MOM-2
Insitu Biological Treatment
300.68 (g)(2); does not meet acceptable engineering practices
for reliability ann is not feasible based on site character-
istics
- 300.68 (g)(3); questionahle effectiveness
- 300.68 (g)(l); no substantially greater public health and
environmental benefits than the no action alternative at a
greater cost
MOM-3
Onsite Treatment
MOM-3C
Steam Stripping (Discharge to stream)
- 300.6R (g)(l); no suhstantially greater puhlic health and
environmental benefits at a greater cost than other onsite
treatment
~OM-3D
Air Stripping/Biooegradation/Filtration/Carbon
Absorption (Discharge to groundwater)
- 300.68 (g)(l); no suhstantially greater public health or
environnental henefits at a greater cost than other onsite
treatment
MOM-4
Offsite Treatment
MOM-4A
RCRA TSD Facility
'. .
- 300.6R (g)(l); no substantially greater public health or
environmental benefits with greater costs

-------
Su~mary co~parison screening for source control ann management of
mi~ration remedial alternatives can be seen on tahles 9 and 10
respectively.
The no action alternative for both source control and management
of migration is carried into the detailed analysis to provide a
basis for comparison to the other alternatives as stipulated in
the NCP.
Tables 11 and 12 summarize the alternatives that were carried
into the detailed analysis of alternatives.
Detailed Analysis of Alternatives
The alternatives evaluated during detailed review and screening
include hoth source control and management of migration alterna-
tives. (Alternatives are re-numbered for simplicity).
Source Control
SC-l
No Action
SC-2A Aerati"on
SC-2B Soil Washing
SC-2C Composting
5C-3
Offsite Incineration
5C-4
Offsite RCRA Landfill
Management of Migration
MOM-l No Action
MOM-2A Air Stripping/Filtration/Carhon
Absorption (Discharge to Stream)
MOM-2B Air Stripping/Filtration/Carhon
Ahsorption (Discharge to Groundwater)
flOM-) POTW wi th Air Stripping
Source control and management of migration remedial alt8rnatives
are summarized Rnd evaluated in tahles 13 and 14. Refer to section
4 of the Feasibilty Study for an indepth review of the detailed
analysts for each alternative.

-------
TABLE 9
C!WAAlSU"i SCREENlt'lJ Fffi ~CE CCMRQ R8-£DI.AL .ALTERNO.TlVES
TI OO\AM GAP.Ptt S I IT
     Et'N IRCN£NT.AL N{) 
R8'fl) IftL .AL TEPJ\'; TI VE  rosrs MLIC f£AL TH a:NS lIDATICA'6 CXWAA I SOO RE5U... TS
SC-1      
ttJ-Action $4O,COO capital 1. Eliminate access to contaITrinated This alternative has ~ retained for
(wi th fenci ng) $1,em 08M  soi 1 saJrce areas by fenci ng detailed developrent to provide a basis
  (30 yrs)   for carpari son to other a 1 temat i ves as
    2. Allows continued release of stipulated in the tcP.
     contcmi nants fran soil soorce 
     areas to the ground.olater, prolongs 
     peri 00 of poor grwrrlNater. 
    3. Restricts future use of site in 
     vicinity of soil saJrce areas 
SC-2      
Ca~i ng     
A. Penreab 1 e Cap A. $158,(00 capital 1. As aOOve, via capping and fencing Alternatives ~-2A throogJ ~-2C have
   $19,300 08M   ~ screened out because they have
   (30 yrs) 2. As arove, espec i ally vi a fl uctu- order of magni tude hi g-er costs and 00
     ating water table not provi de greater envi ronrenta 1 and
B. Surficial     public health protectioo than SC-1.
 Stabilization B. $7,600-$126,CXXJ 3. As aOOve The f1 uctuati ng hi g, water table con-
   capi ta 1   tacti ng the contcmi nated soi 1 near the
   $19,300 O&M   surface makes the eliminatioo of
   (30 yrs)   infiltratioo fran precipitation less of
    4. Reducti on or preventi on of a benefit than WJUld ordinaMly result.
C. ROO r1Jlti- C. $622,000 capital  infiltration into soil source Purping test data indicates that
 1 aye red Cap  $26,400 0&-1  areas resulting in groundwater dra~ in the overburden may be
   (30 yrs)  contcmi nati on (for SC-2B and minimal \tt1ic:h \'OJld not allOri this
     SC-2C only) alternative to be effectively combined
      with a grwndwater ~ing schare.
.      
SC-3     
.Insitu Treat1"ef1t     
A. lnsitu A. $420,000 capital 1. As aOOve Remedial alternative SC-3A has been
I-'\€ra t ion  $55, ()X) O&'~ 5. Reduction or e 1 imi nat i on of screened cut due to adve~ eflvi rDt11a1t
   (5 yrs)  contam nants in soil soorce i~cts and the site cooditions that lii
     areas resulting in an accel~ its effecti veness. . The hi gh Welter tab 1
     ration of grounL~ter clean up could cause operational shutdowns of th
     due to reduct ion in 1 eachi ng treabrent Syst811, and there w)u 1 d be

-------
IDffi::t. A.. ~TIVE
B . S::J il F1 LB1i rJ]
~4
()"si te TrrnUre1t
exc...~::Iti on)
A. O1site
';;'-'3 ti 00
B. C[J:~'ostirg
C. SJil '(~1i:g
m~3LE 9
(continued)
Q}P',.mSJ~ SJIDi)l; R:R 9J..R:E ml1ID.. m£)!It. ft.1miA.TMS
n~~ G4'J..:G: sm:
. *
tn)T'S
$1,;ro,aD ~it:al
$lS) ,aD (ll~
(5 yrs) .
A. $2 ,BJ) ,0:0
Cc;Jital
s-:m,aD ~
(2 yr-s)
8. $3,axJ,CXIJ
C::;J i tal
}3}] ,em ClJ.1
(3 yrs)

C. )J,rm,cm
c:pital
3o~S\),~-DJ ffi~
IJ jrs)
~JID
FUlJC 1-fA..1H ~T1CNS.

6. l.h~ futlre use of site
7. ~is of ~ ratlre
of 9Jil ;;cu-ce aY'ffiS wi 1tn.rt
I11D 1 aTS c1S9:Ci ated wi 111 e:tao/a-
ticrlrerwal
8. El imi rI3tes ri 51< fran spi 11 s
associ at.Erl wi 1tI trar ~ of
c:cnt:rnirated soil s
9. Mi tig3tEs pJta1ti a 1 fa" offsi te
migatiCl'l of soil s em C01tJni-
Nted ~ afta- 1Tea1lra1t
is corpl eted
10. PotB1ti a 1 rel a3Se of ai r emri ssicns
dE to 1Teat:a1t!)"ocess (~-3\
<111y)
11. Pota1tia 1 i rD"&3:Se of a::ntarrirmts
6lmrJ] ~ c1JrirJ] stD"t-
1Bm, ~ble ~ off-site
~rJ] <11 ~ tri!a1Ue1t
systHn (g:-33 <111y)
12. r:e-a-ati Cl'I of resid..a 1 s aftB"
traJ1m:nt rEQ.Ii ri rJ] h:rdI i rJ]  1 e CK'gCrTics
15 . Offa"s a pamcrmt sol uti<11
1. fts iJx:Ne
6. f.s ri:1:JIe
8. As~
9. As cb::Ne
10. As <1xNe
14. ~ am; a 1 fu- re 1 ffi92S assa:i a-
ta1 wi tl1 e~ ati Cl'I i.e. d.5t
g:.~::"'Jtim. \QlatilizatiCl'l of
rortrdr'dm. 9Jil EY'JSiCl'l
nSJ1tirg in ma:e W1tEr iq>:cts
tD ....et1a:ds
12. .\5 fu'e
13. k, ;]:me fJ'" (s(4\ m1y)
(I}PAAI~ r£SJ.. TS
ftire:tial a1terrative 3:-]3 \oOJ1d wn
best vh31 cnp1 Erl with a ~ of
1Teat:a1t alterrative. ~ of
mi~tiCl'l alterratives f1}1..(A am 2B
i rc llJi! co 11 e;ti Cl'I em 1rea tmt of
fI1)J'doater follCK'd by ~ bed<
to tre !1Q.ltI as a di SJX)Sa 1 rrettOO of
1Teated \oBter. 1l1:y are tm-e~
~ate a1terratives in WTich to
ad:h!Ss soil flushirg. .
~al alterratives 3:-4A t:tra.gh
9:4: \t8'e retai re:t fer d2tail en
~1q:m:nt si rre ~ have tre saTE
m:.Er of f1\J]li t.tE rosts cn1
EM roni81ta 1 ta-efi ts ft:r tte 1Teat-
nnrt: of ~ic roltaTTirat:d soils.
S(4) ....as 9:Tooa:! aJt. Its costs are
ill ~ of mapi t.tE grmta" tlm ttose
of 3:-4A ttmdl ~4C (rffi1 JQJ tri1 C1J.1
costs to capital costs) cn:1 it ct5 rot
prcvi ~ s i gTi fi Cii1tl Y ~t2r erwi roo-
iT8Ttl1 Ixn:fits. S(-4-A-o struld ~
9;?1a:ta:t ~1U'e 0 if 1re3tDi1i~ st:Lqf
mta 9.bsBltiates <2'l ~tE
~"rfOr.:F:1:e of ttEse. ~ are CD}-
S1 d3-B:j to t€ r.r:re rost effu.'"ti ve &d1
~ ircir\8'3ticn of rrcx:tratEly

-------
IrnJ) lit tt.. rrn~TIVE
D. Q1site
Irci reati CJ1
S:-5
ens; te RJ
-------
TABLE 9 (continued)
m,p"~SJJ SJ@.8I; RR SJJU: romu. f£'.ffiIfi.. ftLTERt.\"11\£S
ru~ ~ SI1E
trnl)IJL ti.TIRv.,TM:
*
m;rs
ENiIRJM:NT.rt. lID
PJIJC 1-£tt..1H cmsrI:ffi4J1(}5

17. ~ cOO.'e
awAAIg}J ~TS

It \oQJld ~ ~ tD lJ'Wi
-------
~ ft"T'ERW1VE
MJ+1
~fctiC11
t1M-2
Insitu BiolOJica1
T r8:1tre1t
KJ+3
CrG i ':2 T f'ffi tr.mt
A. ,;ir Stri~irg
r" i1 i;C1 ti OrY Car'.:ro
:'::5:r,J ti m
( .j] ~d~ ID st"'e:IiV
~.
L.'..BLE 10
QJ.pAAls)~ SA:Df.~ Fffi ~+W1NT CF MIffiATICJ.J ~lPl ft~M\TMS
mm:M~sm .
*
rosTS
$3),em ~ita1
$241 ,em CS'+1
(1-4 yrs)
gj) ,em ct.M
(5-J) yrs)
£i),em ~ta1
~,em ~
(5 yrs)
A. 9- ,00 ,em C4)ita1
'5EBJ ,IJJJ (1l.1
(5 yrs)
EN/lRJM}l11t ~(N)
1. ~te'" will c1 €tT1 l.p with
tire as a result of ratlra 1
processes
2. Presa1t ttreat regat.e1 de 11>
i r5ta 11 atim of a wrtI:r 1 ire
3. Ire 1 ui:s nmi tni ~ 11> d:rts:t
offsi te C01taTrinaticn trat cna1 d
1TreatB1 otte- ~ resicBtt-
ia1 are:1S (i .e. ~ [)ive)
4. ~ res i nsti 1lJti of
~
4. P6 ii:DIe
7. rre; rot nive1y CD1tro1 gmrrl-
W3t3'" CD1tarri nati 01, a:rrt:i I'\B1
di~ crd migaticn of
cxrrt:aJTI n:rrts
8. \.h:ertai~ iM1~ in area
00e1t of trretre1t effectivEress
9. '...';11 rot br'e:kchl1 all ~
present (F{Bs crd sore extrcI:t-
ctJ 1 es wi 11 rot be affa:1a1)
3. As cfuIe
4. As cb:JIe
6. As ct:me
10. [T..es l)Jt n:strict ~ LfE
a:r.tTO 1 s
11. ():n;tr J:ti m of f a..-; 1 i t;y fMj
IX r,-q.r. re i rs:J'J 'BltatiCJl
cx:M>AAIs:N ~ 1'5
This a1tan:ltive ITi¥ iJe victJ1e fer
tilis 'site crd has b:a1 reta.ire:1 fa'"
ci?tail e:1 <:PIe1 qJTB1t tD ~i~ a
basis fer ~SJ1 11> otte-
a 1 tEmrti ves as sti III 1 ata:1 in tte ~.
This altErnative res I:m1 g:room ClJt.
A1 tto.sj) ttri s a 1 taTative is rot a
~ 1B:tro1(J:]J it has stI:w1 ~ise
as a p:1SSive trffitre1t systan. ~,
tte tire rEqIired to attain ~
1EM:1s ~ ~ tt'at of tte
ro-rtlCJl altErnative. (Ccnsi cBi ~
th:It rntura11y cx:a.m~ ~
rave a1rm::y redm:J a:ntanirmt
lele1s.)
Al1:an:1tive ~rn-]) ffis b:a1 xroo ed
0Jt ~ oorp3..'iscn with t.fH-:B. TIo..d1
tte ro;ts are tte sore on:13" of
rra]1it:J..J:E. TI~ rost of bicxi."Tcc:htiC11
i s ~ tD i rcrEX1Se tte rost. Al ro,
th~ fa- ~rn-13 are ~~ tD 00-
-------
~ tt~TNE
B. Air Strif:Pirg
Fil tTati Cl)fCartxJ1
Am'ptiCJ1
(cti~ tD
g-curG.atEr)
C. StEa'n Strif:Pirg
(cti~ tD
stTean)
D. Air Stri~irg
Bi OO:9'ati crY
Fil tTati oriCarta1
Mg)rptiCJ1
(cti~ tD
~tEr)
MJ+4
Offsi tE TI"ffitTmt
A. IT! Fcd1i~
8. FUr,.., wi tl1 01si tE
Air Stri~irg
TABLE 10 (continued)
Q}P~S}J ~.LN% RR ~~T CF ~11~ ~I!t. tt.'1'mM'wB
n~~1 ~ sm:
*
ems
B. $2,JqO;aJJ ~ital
$SJJ,em c&'-1
(5 yrs)
c. $2,JX),em ~ital
$Sa),em C1l-1
(5 yrs)
D. $2,g)),aJJ ~ital
~,em 08M
(5 yrs)
A. $1,!ill,em ~ital
$10,a:op:xJ (B.1
(5 yrs)
B. $2,lOO,aJJ capital
~,aJJ 08M
E}NIJUM}.ITtt. OJ.5IDAl1rns
Cn:23tE r'e9dtive vi ~ 1 iTpa:ts
3. As It:DIe
4. As iJ:xJIe
6.As~
10. As ~
11. R>tB1ti a 1 fer spill s c1ri rg
trar6prt via 1ru:kirg or in
se.e-lire
CIM1\L(I~ I£S.l 15

~ ~ Wa-eas ttose fer
bicd:grcd2tiCJ1 are rot. nae~, fer
silTil ar EWi rorJTe1ta 1 ta-efi ts, 1te
oosts fir 11M-33 will a 1 \tByS be 1 ess
1tBl ~J) cnt it will rot be as
SB1Sitive tD efflLB1t cnQ;,ltT'ati01S.
MJ+J: has ta:rI 9:) 00 e:1 aJt ~ cmpa.
risar witt! M:M-3>\. Pgain, ttn.gh 1te
oosts are tte ~ ~ of rMJli 1ld:!,
1te-e is. 11) q..est'iCJ11t'at r1M-~ is
less ~ive ttm MJ+3::, EMJ1 givE!1
tte lTCa'tai nties i rwlved in tte oosts
fir ea::tt. 11'e ta-efi ts assa:i ata:! wi tt!
ea::tt are a:nsi cEra1 sml ar.
MM4'. tBs ta:rI 9:;)' &:f t;d aJt 5i rce tte
CDSt is cYI ~ of 1TBJTi~. i.e. 10
tm:s. 1t'at of 111+48 wi 111 tte sare
€Wi rommtal I:a1i!fi ts.
1m.! msts ~ t.m" ftes or ti wi rg fe=s fty di 5p)Sd 1 of a:rrtaTri rBtaj gn:url.ata" 'fhidl wi 11 be ; ra.n-ro OIeI" tte 1 i fe of tte
ro,QJal ~.
1::&~ costs gi'/'J1 are .:nual W5ts (rc J:'''ESa1t aral.f.)is was p:rfum:rl) .
-------
i AS~E 11
SU~~ARY OF S~~RCE CON7ROL ALTERN~T!VE SCR~ESING
Tr~KHA~ GARAGE SITE
Alternatiyes Screened
in this Section
Alternatives Retained for
Detailed Development

SC-1 No Action
SC-1 No Action
5C-2 Capping

SC-2A Permeable Cap
SC-2C Surficial Stabilization
SC-2S RCRA Multilayered Cap
SC~3 Insitu Treatment
SC-3A Insitu Aeration
SC-3B Soil Flushing*
.
SC-4 Onsite Treatment
5C-4 Onsite Treatment
SC-4A
SC -4 B
SC-4C
~C-4D
Aeration
Soi1 Washing
COr.1posting
Incineration
SC-4A Aeration
5C-4B 5011 Washing
SC-4C C~~posting
5C-5 Onsite RCRA Landfill
5C-6 Offsite Incineration
SC-5 Offsite Incineration
5C-7 Offsite RCRA Landfill
SC-7 Offsite RCRA Landfill
L.
'\
-------
iASLE 12
S'J":'~';KY O~ 1,~,';'\';3~~~:NT OF MIGP..!\TIO~.; ALTERi;.;rrVE SCREENING
TINKHA~ GARAGE SITE
Alternatives Screened
in this Section
MOM-l No Action (with monitoring)
MOM-2 Insitu Biological Treatment
MJt1-3 Onsite Treatment
MOM-3A
Air Stripping Filtration/
Carbon Adsorption
(Di.scharge to stream)
~
Air Stripping Filtration/
Carbon Adsorption
(Discharge to groundwater)

MJ~-3C Stream Stripping
(Discharge to stream)
MJ~1-3 B
MO~-3D Air Stripping Biodegradation/
/Filtration/Carbon Adsorption
(Discharge to groundwater)
MJ~-4 Offsite Treatment
MJM-4A Offsite Treatment at
RCRA TSD Facility
MJ~-4a Offsite Treat~ent at
POTW with Onsite Air
Stripping
A.;l. terna t i ves Reta i ned for
Detailed Development

MOM-l No Action
MOM-3 Onsite Treatment
MOM-3A Air Stripping Filtration/
Carbon Adsorption
(Discharge to stream)

MOM-3B Air Stripping Filtration/
Carbon Adsorption
(Discharge to groundwater)
MJM-4 Offsite Treatment
MOM-4B POTW with Onsite Air
Stripping
.., ::c'~i), n:.~-.3~, and :-:J:-:-38 include soil flushing. Soil flushing
\.)'Jld be used to aug:-'e:nt natural flushing r:echanis~s during
-------
REMfOIAL
AL HI!NATI V[
SC-I
NO Action
SC-2
[xcot\latlon
of Contonl-
na led Sot 15
wt th On-
~ite Treat-
ment
A. Aer4tlon
8. Com-
posting
C. Sot1
Washing
SC-3
[xcot\latlon
of Contcl1ll-
nd ted Sot1 ~
and Off-
SI te Incln-
erdtlon
SUMMARY ANALYSIS OF SOURCE CONTROL REMEDIAL ALTERNATIVES

[NVIRONM[NTAL
& PUULIC HEALTH:
TECHNICAL
Hed I III
o Contaminants can be
Isoldted from the
population eliminating
the threat of direct
contclct.
o Cont~lnants will
continue to leach 'raq
soils Into the ground-
wclter.
HedlUl'll
.0 Treatment 0' solh re-
moves threat.
o Treatment technologies
are stt11 being
developed for hazardous
wotste sites, and there
could be difficulty
during Implementation.
High
o Treatment of soils
remo\les threat.
o Technology hots been.used
and demostrated .t other
halardous waste ~Ites.
TABLE b
INSTITUTIONAL
low
o Does not comply with
RCRA-40 CFR Part 264
Subparts G (closure and
post closure). L (waste
piles), dnd N
(lclndfllls); Executive
Order 11990; and fish
and Wildlife
Coordination Act.
High

o Will comply with RCRA 40
eFR P.rt 264 Subparts G.
L; N; Executive Order
1990, and the Fish and
Wildlife Coordination
Act. ..
High
o Same IS SC-2.
low
o laprovements to bio-
logical environment will
occur graduc1l1y.
o leaching of contdmlnants
from soil Into the
groundwater will
continue.
o future use 0' the 5011
source .re.s would be
res trlcted,
High
o Improvement to the bio-
logical environment will
occur rapidly,

o Eliminates leaching fr08
contaminated sol1~ Into
the groundwa ter.
o Future use 0' 5011
source areas restored;
eliminates the risk fr08
contact with contdUl-
na ted soils.
High
o ScSI1Ie as SC-2.
o Potential risk fro.
transport of
. co~tdnlnated soils
-------
REM[DIAL
AL T[UNAT lYE
5C-4
[.cdllatlon
of Con tdlD-
tnHcd
Sui Is .snd
Off-Sltc
01 spos.sl fn
4 RCRA
Ldndfll1
TAnLE 13 (Continued)
SUKMARY ANALYSIS ~f SOURCE CONTROL REMEDIAl AlTERNATIVES
nCHNICAl
Hedfura
o Treatment of sofh
removes threett.
o Technology hets been
demonstr.sted to work.
but the potentfal for I
lCdk In future Is
present.
INSTITUTIONAL
Hfgh
o Same as SC-2.
ENVIRONMENTAL
& "UULlC UEALTH
Medfum
o Same as SC-J.
o Risk from potentIal for
fdllure of offsfte
-------
R[MlDI~
AL IIIINA fI V(
---
11(»4 -1
No Action
t.
~H-2
RCfQOVa 1!
[Atrelct1on
(5011-
fI u~hl n9)
oInd On51 te
T rCeI tJnent
A. A I r
Strlpl
(Jrbon
Oh-
ctl4rge
tu
Tribu-
t4ry
B. A I r
Strip!
C.Htlon
[) I ~-
ct.4rge
to
Groun~
lid ter
TABLE 14
SUMMARY ANALYSIS OF HAHAGEMENT OF MIGRATION REMEDiAl AlTERNATIVES
HCHNICAl
Medlin
o Costs are 10~.
o Aquifer wtll eventually
restore due to reductton
viol n4turcll processes.
o Potentldl threat ~o
users of the aqutfer who
clre not on the wolter
11 ne.
o Constructton and fm-
pl~nentdtlon are easfly
ace omp 1 Is hed .
HedlUli
o Can fntercept the con-
t~lnatton. but requires
01 complex treatment
s)'stun.

o potenttal for frequent
shutdown of treatment
SyHl1n due to
mJlntendnced and
servlctng of equfpment
(I.e.. clednlng clnd
drdlnlng of sludge)
o Conttnudl monttorlng re-
quired In residential
..ells and of the tre4t.
mcnt process as well.
INSTITUTIONAl
low -
o Does not c~ply wtth
RCRA-40 CFR P.rt 264
Subpart F; Eaecut he
Order 11990; Groundwater
Protection Strdtegy; and
Fish & Wtldlffe
Coordtndtlon.
Hfgh

o Wf 11 cC)IIply with RCRA 40
CFR Part 264. 262. 263
and Executtve Order
11990; CWA Sectton 404;
NPOES; Drtnkfng Water
Stelndards; Groundwater
Protectlon'Strdtegy;
Fish and Wfldllfe
Coordlndtlon Act.
E NY I RONME N TAL
& PUIILlC tt[ALTH
low-Medium
o Improvement to the bfo-
10gle41 envfronment will
be gradual. Future use
of the aqutfer will be
restored.
o No stress observed fn
",et1c1nds. (Med)
o Potential threat to
users Qf the groundwater
who are not on water
line. (Low)
High
o IMprovement to the bfo-
10gfcal envfronment wtl1
be rapid and future use
of the aquffer e4n be
restored.
o Mltfgates po~entfal
threat from contamfnated
groundwater to users not
-------
I!lMf [jIAl
At. It HNAII V[
-_._-
HflM -)
kt~!lO\l~ 1 /
[Atrdetlan
d fhl 0 t f-
~ It e T red t-
ml'flt dt 4
1'0111 with
On~lte dlr
Hrlpplng
SUMMARY ANAlYSIS Of HAHAGEH[NT Of MIGRATION REMEDiAl ALTERNATIVES

ENVIRONMENTAL
& PUBLIC ItLALTH
HCttNICAl
Hed 11111
o C~n tntercept the COlt-
tc1l1lln4ttan, but re(lulru
ct pretredtment system.
o potenttal for shutdown
of treel tJIIent sys t~ due
to mctlntcndnce ctnd
servicing of equipment.
o Conttnual monltortng
required tn resldentt.l
we 11 sand the tred tment
process .IS well.
TABLE 14 (Continued)
I NSTI ruTlONAL
Htgh
o S~e '5 HOH-2 .bove.
o Pretreatment penatt.

o Intra-muntctpal
agreement needed bet~en
Derry 4nd Londonderry. .
, ",.
-------
Consistent with the National Contin~ency Plan, the detailed
an~lysis of alternatives addresses the technical feasihilty (300~68
(h)(2)(iii)), institutional raquire~ents (300.fi8(h)(2)(iv)),
puhlic health and environmental impacts (300.68(h)(2)(iv)) and
(300.68(h)(2)(vi)) of the remedial alternatives remaining. The
feasihility study guidance manual was used for the detailed analysis
of the alternatives and the manual incorporates the screening
criteria of the National Contingency Plan 300:68(h)(2)(i-vi).
The detailen analysis of alternatives begins with a refinement
and specification of the alternatives under consideration in
accordance with 300.ry8(h)(2)(i). The alternatives were then
evaluated in terms of their engineering implementation,
reliahility and constructahility as indicated by 300.68(h)(2)(iii).
This evaluation is referred to as the technical Feasibility
evaluation within the FS report and in summary Tables ~3 and
14. Furthermore, an asseSsMent of the extent to which the
alternative is expected to effectively prevent, mitigate, or
minimize threats to and provide adequate protection of public
health and welfare and the environment was conducted. This included
an evaluation of, and extent to which, each alternative attains or
exceeds applic3hle or relevant and appropriate Federal public health
and environmental requirements consistent with 300.68(h)(2)(iv).
This analysis is referred to under the headings of Institutional
RequireMents and Public Health ann Environmental Impacts within the
FS report ann in summary tables 13 and 14. Finally, a detailed
cost analysi~ for each alternative was conducted including
operation and maintenance costs and the distrihution of costs
over time, as in~icated in 300.68(h)(2)(ii) of the NCP. This includes
the total esti!nated costs for each of the six source control
alternatives and four management of migration alternatives.
The total cost given for each alternative represents a sum
of the costs of the components which comprise that alternative
and all associated indirect costs. Costs are within a +50, -30
percent accuracy range.
5C-l No Action
No action for source control is limited to fencing those areas
which present a significant direct contact/ingestion risk.
No action a1so includes long term monitoring.
Leachfields - The No Action alternative for contaminated leaching
fields of the Woodland Village Condominium Complex entails leaving
this area as it presently exists: no fencing is proposed. The
conta~inants lie under the leachfields natural concrete cap
an~ are covered with top soil. Contaminated media is virtually
inaccessihle to sensitive receptors such as small children
and animals. .
-------
Swale - The No Action alternative for this source area may entail the
construction and maintenance of a chain link fence with several
strands of barhed wire at the top. The fencing must be of sufficient
height and strength to deter people from climhing over or breaking
through. To provide access to the soil source areas, locking gates
will be required. Signs or placards may be placed at this soil
source area, instructing unauthorized personnel to keep out. The
swale area would require about 140 linear feet of fencing.
Soil Pile - The No Action Alternative for this source area is the
same as described under Swale and wouln require about 180 linear feet
of fence.
Field Southeast of the Tinkham Garage - The No Action alternative for
this soil source area is the same as described under the Swale. This
source area would require 1,100 linear feet of fence. The operation
and maintenance of the fencing to ensure its integrity over
the thirty year life of this alternative may entail fence repair.
The implementahility, reliahility ann constructability (300.6R(h)(2)
(iii) of the no-action alternative received a medium ranking
for all of the source areas. The construction of a fence is
very straightforward and requires only a short period of
time to implement. However, it is not reliable in preventing
contaminants from leaching through to groundwater.
The evaluation of the no-action alternative consistent with
300.68(h)(2)(iv) indicates it does not attain or exceed applicable or
relevant and appropriate Federal public health and environmental
requin~Jnents. Specifically, it noes not comply with RCRA 40 CFR Part
264 which regulates the disposal of hazardous waste. The relevant
ann appropriate reguirenents for the soil pile are RCRA 40 CFR 264
Subpart L (Waste Piles), which states that waste piles can only
be usen for treatment or storage of wastes, not for nisposal.
The relevant and appropriate regulations for the leachfields,
swale and field southeast of the garage are 40 CFR 264 Subpart N
(Land~ills) and 40 CFR 264 Suhpart K (Surface Impounnments).
In order to co'oply with RCRA, a permanent cap is required or
all waste, resinuals ann contaminated subsoils must be removed
or tceated to levels that are pcotective of puhlic health
and the environment. Uncier RCRA pact 264, no action would be viewed
as (Hsposal of contaminated soi ls in the soil pile, leachfielcis,
swale and field arGas without the required cap. In addition,
the no action alternative is not protective of the wetlands
onsite. The source acea behind Tinkham's garage includes an
existing portion of the wetlands as icientiEied in figure
6. Any surf.icial transport via erosion wouln result in continuen
contamination of the seciir1ents and surface water of the wetland in
violation of Executive Order 11990.
Moreover, the no action altGrnative allows for the potential
downward migc'\tion of contaminants from the soils into the
groundwater, prolongs the poor quality of the groundwater
-------
c...
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LEGEND
"'I
~ CONTAMINAT(O WfTLAND
ruLLI AREA ( a 000 9Q ft )
~
"
.,
FIGURE 6
CONTAMINA
WETLAND
, 'i.,
''1
\
I?O
190 'ICT
-'-.--.
----- ~-_.-
----- ----
---
COllI
--- --
-------
and increases the potential for offsite migration to residential
wells along Ross Drive. Prolonged leaching of soil contaminants
into the Unnamed Tributary will increase the potential for
exposure to the contaminants. The potential exposure to
children is a concern as they are a sensitive population.
Although fencing would be used to restrict access to the
contaminated soil source areas (except the leachfield), the
potential for wind and water erosion of the soils exists for
the source area in the field behind the garage.
Under the no action alternative it will take a long period
of time for the contaminants to reach acceptable levels in the
soil if left untreated. Some of the contaminated soils include
till layers containing fine-grained materials which have a
lower hydraulic conductivity and less pore space than sand. This
enables some organic compounds to adhere to the soils and be
released slowly over time. Over the long term, improvements
will occur as a result of naturally occurring processes such as
biodegradation. In the interim, infiltration of precipitation and
the rise and fall of the water table within the contaminated soils
will generate leachate and thereby promote the continuing
contamination of the underlying aquifer.
SC-2 Excavation of Contaminated Soil with Onsite Treatment (aeration,
composting or-soil washing)
The aeration (low temperature thermal stripping) system under
consideration for the onsite treatment of contaminated soils at
the Tinkham Garage site was developed by Roy F. Weston, Inc. for
the U.S. Army Toxic and Hazardous Materials Agency for defense
related facilities. The result of several pilot studies at heavily
contaminated defense facilities have demonstrated greater than
99.99% removal of volatile organic compounds from contaminated soil.
Some reduction of extractable organic contaminants is anticipated.
Mechanical aeration is increasingly being used for the clean up of
volatile organic contaminated soils at several industrial and defense
sites. The McKin CP,RCLA site in Gray, Maine and the Triangle Chemical
CERCLA site in Bridge City, Texas are successfully utilizing this
process in pilot scale.
The composting option provides for the controlled reduction of the
volatile organic compounds in soil source materials. Many of these
compounds are expected to be reduced to very low levels in the soil
mass through enhanced biodegradation and aeration. Composting is
an established, effective process for a broad range of wastes
including agricultural and sewage sludge. It holds promise for
the removal of volatile and extractahle organic compounds, such as the
ones found at the Tinkham site.
The soil washing alternative involves mixture of contaminated soil
with a leaching ~edium, and extraction of this medium with the
associated contamination from the soil. It has heen applied at a
number of industrial sites throughout the country, and shaws pro'nise
for contaminants and media similiar to those at the Tinkhdm site.
ijr'
-------
One of these t~ree technologies would b9 chosen under SC-2. Pilot
stuiies condlJcted during design phase will indicate the best
technology for use. The three technologies are expected to have
no substantial long-term and short-term environmental impacts that
can not he effectively managed. As a result, the selection of the
appropriate technology will be based on technical feasihility,
reliability and cost-effectiveness.
Whichever treatment approach is selected, excavation of source areas
down to the seasonal low water tahle will be required. Excavation
removes the contaminated soils from the source areas to prevent the
pollutants from being further released to the surrounding environment.
Excavation of contaminated soils will be required from the field
hehin~ Tinkham's garage (10,800 yd3), and potentially from the leach
fields, soil pile and swale.
Treated soils will be placed back into the area from which they were
excavated after treatment and these soils will be graded and
revegetated.
Aeration, composting and soil washing are presently considered
innov3tive or advanced technologies hecause of their lack of
final field demonstration. The evaluation of these three in
terms of engineering implementation, reliahility and construct-
ability (300.68(h)(2)(iii), has revealed these alternatives to be
technically sound, and they are expected to be appropriate to
reliably minimize present or future threats to public health or
welfare or the environment (300.68(h)(2)(v». A medium ranking
is indicated as a result of their innovativeness and the need for
pilot studies prior to final implementation at the Tinkham site.
As mentioned above, the excavation of contaminated soils and onsite
treatment by aeration (SC-2A), soil washing (SC-2B) or composting
(SC-2C) will require the excavation of soils in the field southeast
of the garage, including soils within an area designated as a
wetland. The area that will be affected is relatively small
(appr.oximately 8,000 square feet). This alternative will be
designed to be in compliance with Section 404 (Dredge and Fill of
Wetlands) requirements. Rest engineering practices will he
inplemented during excavation to minimize adverse impacts
and restor~tion activities will be implemented to speed the
naturAl recovery process of the wetland. This area is expected
to recover quickly, from excavation and replacement.
The onsite treatment of contaminated soils will reduce contaminants
in soils to levels protective of public health and welfare and the
environment. The determination of the soil levels will be consistent
with RCRA d81isting requirements and guidance. After treatment
to a level consistent with applicahle RCRA provisions, the treated
soils would he returned to the site(s) of excavation.
. The evaluation according to 300.68(h)(2)(iv) of the NCP
indicates that SC-2 complies with RCR~ PArt 264 Subparts G (Closure
or Post Closure), L (Waste Piles) and K (Surface Impoundments).
-------
The relevant RCRA regulations require the re~oval of waste and waste
residues. The excavation criteria for the field and modeling work
for the condominium areas will be consistent with the RCRA removal
requirements. Also, since the removal of contaminated soils
will reduce levels of contamination in the wetlands, this
alternative will comply with Executive Order 11990 and with the
Pish and Wildlife Coordination Act. The removal of contamination
from the wetland is necessary to meet remedial objectives and be
protective of public health. The removal of contamination does
not permanently harm the wetland and is consistent with Executive
Order 11990. The transport off site of any sludges or spent
vapor phase carbon will be in compliance with appropriate
RCRA Parts 262, 263 and DOT regulations 49 CFR-171-179.
Aeration transfers the contaminants to an air stream which then
passes through a fume incinerator or afterburner. It is expected
the burner will destory up to 99.99% of the contaminants at high
temperatures. The resulting air stream will then be vented to a
stack. '
As proposed, aeration, composting and soil washing are all enclosed
systems and air emissions will be controlled. The air stream
generated from any of the three will pass through a vapor phase
carbon unit for removal of hazardous organics and will meet applicable
RCRA air emmission standards.
The excavation and treatment of the contaminated soils minimizes the
potential exposure to local and transient populations from this media.
Furthermore, the potential downward migration of contaminants from thE
leaching of contaminants in soil to the groundwater is mitigated.
Consistent with 300.68(h)(2)(vi) of the NCP, an analysis was conducted
of any adverse environmental impacts, methods for mitigating them
and the costs of mitigation. This analysis indicated the primary
adverse effects that are possible from excavation and treatment
of contaminated soils are:
1 .
Local and transient populations can he potentially exposed to
releases in the form of fugitive dust and volatilization of
contaminants which can occur during excavation.
2.
Transient populations, specifically site workers, can
potentially he exposed to contaminants during the handling
and disposal of residuals generated during treatment. .
3.
There is exposure potential from onsite accidential spills and
releases.
The magnitude of these risks is not anticipated to be great. These
potential impacts will be effectively managed during implementation.
The details of the air mOnitoring network and engineering controls to
minimize or eliminate adverse effects from excavation will be developed
during design. Cost estimates reflect anticipated control measures.
-------
Consistent with 300.68(h)(2)(iv} of the NCP, the ove~all puhlic
health and envi~onmental protection r3ting of this alternative
is high. This is because the original risks and sources of exposure
are removed, while the new sources of potential exposure created
during excnvation a~e comparatively mino~ and controllable.
The removal of the contaminated soils will ~esult in an immediate
iM~rovement of the biological envi~onment and human resource use of
the site. The risk of direct contact and transport of contaminated
soils onsite or offsite is minimized, as well as the potential for
leaching. of contaminants f~om the soil sou~ce areas into the ground-
water. This will improve the water quality of the wetlands, the
Unnamed Tributary and onsite groundwater.
The Agency has determined that the small portion (8,000 square feet),
of the wp.tland located behind the ga~age which is contaminated will
have to be excavated. This will ~esult in a sho~t-~erm adverse
impact to the wetla~d. However, this impact is not considered
significant and the wetland is expected to recove: quickly.
Overall the rating for this alte~native is high hecause improvement
to the environment is rapid and potential human resource use is
~esto~e1 with only Minor adverse effects during construction.
Soil ~emoval accelerates g~oundwater clean-up by reducing levels
of the leachate from the contaminated soils in the unsatura.ted
zone. Additionally, it eliminates the direct contact/ingestion risk
from the field hehind Tinkham's ga~age. 5C-2 is expected to
effectively minimize threats to, and p~ovide adequate protection of,
puhlic health and welfa~e and the environment.
5C-3 Excavation of Contaminated Soils and Offsite Incine~ation
This remedial alte~native centers on excavation of the contaminated
soils similia~ to 5C-2 in the sou~ce a~eas and disposal of
part o~ all of the exacavated lOate~ials to an offsite incine~ator.
The incine~ato~ must be capahle of accepting soil with PCBs
in concentrations of less than 50 ppm and medium to low
levels of volatile organic compounds. Incineration may
destroy 99.99 percent of organic contaminants. In addition to
these effo~ts, this remedial action incorpo~ates refilling, site
grarli~g, and a vegetative cover of excavated a~eas.
Technically, the engineering inplementntion, reliahility and const~uct-
ahility evaluation (300.68(h)(2)(iii)) ranked this alternative high.
The reliahility of incineration has been proven at other sites and
excav~ted soils would be re1noved to an existing, pe~mitted
incineration facility.
The irlstitutional evaluation of this alternative (300.68(h)(2)(iv)
found this alternative to he in compliance with RCRA Part 264
Subparts G (Closu~e and postclosure) and L (Waste Piles). The t~anspo~t
-------
and treatment of contaminated soils offsite to the incineration
facility will comply with RCRA Parts 2~2, 263, 264 and DOT
regulations 49 CFR Parts 171-179 and 387.
Executive Order 11990 and the Fish and Wildlife Coordination Act is
complied with,since the treatment of contaminated soils will
remediate the contamination occurring in the onsite wetland. This
alternative also complies with guidance on the procedures for planning
and implementation of offsite remedial activities set forth by EPA.
The beneficial and adverse impacts (300.68(h)(2)(vi)), for
this a~ternative are the same as those discussed for source
control alternative 2 (aeration, soil washing or composting).
Additional henefits include the fact that there is no potential
exposure to onsite residents due to air emissions or potential
onsite spills during onsite treatment. However, there is an
additional adverse effect. There is the potential exposure
to the transient population (i.e., site workers), from extensive
handling of soils during transport to the incinerator in
addition to the adverse impacts cited under 5C-2. These
adverse impacts can be mitigated through the use of engineering
and personnel protection controls.
This alternatlve has the same environmental benefits as described for
source control alternative 2 (aeration, soil washing or composting).
The adverse impacts are also the same, with the addition of potential
hazards of spills and associated problems with the transport offsite
of the contaminated soils.
Overall, this alternative was ranked high, and it is expected to
effectively minimize threats to, and provide adequate protection
of puhlic health and welfare and the environment.
5C-4 Offsite RCRA Landfill
This remedial action alternative centers on excavation of the
contaminated soils (similiar to 5C-2), in the source areas
and disposal of all the excavated material at an offsite
landfill. The landfill must be capable of accepting soil
with PCBs in concentrations less than 50 ppm and medium to
low levels of volatile organics. In addition to these efforts,
the remedial action incorporates refilling, site grading and
vegetative cover to original site conditions.
Landfilling of contaminated soils has occurred in the past;
however, EPA policy prefers destructive technologies where
feasihle. This technology has been demonstrated to work, but the
potential for leaking in the future exists.
-------
The evaluation of institutional ~equi~ements unde~ 300.68(h)(2)(iv)
of the NCP indicates SC-4 would be in com~liance with RCRA
Pa~t 264 Suhpa~ts G (Closure and Postclosure), L (Waste Piles)
and N (Landfills). The transport and-disposal contaminated
soils offsite to the landfill will comply with RCRA Pa~ts
262, 263, 264 and DOT regulations 49 CFR P~rts 17117g and 387.
Executive Order 11g90 and the Fish and wildlife Coordination Act are
com~lied with, since the excavation of contaminated soils will
remediate the contamination occurring in the onsite wetland.
The institutional ranking of this alternative is high since it
is in compliance with Federal and State requirements, and
adequately protects public health and welfare and the environment.
The transportation of excavated soils
local, state and federal regulations.
be shipped with applicahle permits.
will be in compliance with
All the materials are to
This alternative has the same puhlic health and welfare
benefits as those described for SC-3. The adverse effects
are also the $ame, with the addition of the potential failure
of the offsite RCRA landfill, causing contamination of surface
wateL and QLoundwater.
This alternative has the same environmental henefits as those
described for SC-2 (aeration, soil washing or composting). The
adve~se impacts are also the same with the addition of the
potential haza~ds from spills during transportation and for the
offsite RCRA landfill to le~k and contaminate surface water and/or
groundwater.
The overall ranking of this alternative is medium. This is primarily
because, although this technology has been demonstrated to work, the
potential for leakage is present.
Detailed Cost Analysis for Source Control Alternatives
Consistent with 300.68(h)(2)(ii), detailed cost estimates (+50%,
-30%), including operation and maintenance costs, capital costs
and p~esent worth, ~re p~esented for each source control alte~native
below (see section 4 of the Feasihility Study Eo~ detailed costing
fo~ each alternative).
Due to the technical difficulties in using groundwater models
on this site to p~edict the mig~ation of contaminants through
the overburden and into the aquife~ (2 till layers of dec~easing
permeahility values and fractu~ed bedrock), a sensitivity
analysis of soil volume in the field behind the garage was
performed (see tahle 15). EPA has determined that excavation
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TABLE 15
  Se n sit i vi ty Analysis of Soil Volume in   
    Field Behind Tinkham Garage   
    A. Capital Costs     
     ($ x 1,OUO)     
Contaminant Soil SC-2A  SC-2B SC-2C 5C-3 ~ 5C-4 .Risk 
level Volume Aeration Soilwash Composting I nc i ne.rat ion RCRA level in
(ppm) in field        landfill Field 
rvo Behind  "       Behind 
 Ga r~ ge         Garage 
 (yd )          
100 930 510  750 910 150 150 1. 9X10-:
10 6,500 1,610  2,370 2,840 470 470 1.9x10:6
1 10,800 2,170  3, 190 3,820 630 630 1.9xlO 
   B. Operating and Maintenance Costs   
     ($ x 1,000)     
, 100 930 70  40 30 1,520 400  -4
 1.9x10-5
~G 6,509 480  290 210 10,620 2,830 1.9x10-6
1 10 , 800 790  490 340 17,640 4,700 1.9xlO 
    C. Present Worth Costs    
     ($ x 1,000)     
100 930 630  820 960 1,670 550  -4
 1. 9xlO 5
10 6,500 2,440  2,870 3,200 11,090 3,300 1.9xlO:6 .
1 10,800 3...540  4,040 4,410 18,270 5,330 1.9x10 
  .         
ic
Estimated risks were calculated for the ingestion of contaminated soils and
based on the assumptions outlined in the NUS Endangerment Assess~lent prepared
for the Tinkham Garage Site.
.'
'"
.
-------
should proceed to a total volatile organic (TVO) target level of 1 ppM
in contaMinated soils from the field behind the gar~]e. The 1 ppm of
TVO corresponcts to the lateral extent of contamination in
surficial ~edia. Vertically, excavation will proceed to the seasonal
low water tahle. This corresponds to approximately 10,800 cuhic
yards of contaminated soil to he excavated. The 1 ppm houndary
is believed to represent the approximate extent of detectable
contamination.
The 1 ppm cleanup target level is considered appropriate for two
reasons. First, at 100 ppm the ingestion risk associated with this
area has been conservatively estimated to be 1.9xlO-4. This
level is not considered appropriate to provide adequate protection
of public health and welfare and the environment. At 10
pp~, the estimated lifetime cancer risk is 1.9xlO-5 which
falls within the target risk range for remediation. However,
by removing contaminated soil to 1 ppm, it is expected that
the groundwater remediation time will be reduced, in addition
to providing greater protection to public health and welfare
and the environment. Furthermore,the shorter time required for
gr.oundwater remediation is consistent with EPA's policy of
implementing rapid cleanups of all current and potential drinking
water. Finally, based on annual operation and maintenance costs
associated with each management of migration alternative (see
Table 16), this shortened groundwater treatment time is likely
to result in a more cost-effective groundwater clean-up.
The need for excavation and treatment of the leachfields, the soil pile
and the swale has yet to be determined. A significant direct contact/
ingestion risk is not attributed to each of these source areas.
Excavation and treatment of contaminated soils will proceed based
upon an evaluation of the potential for individual source areas
to contribute to groundwater contamination. This will require
the use of an analytical.model capahle of predicting the impacts
of these individual source areas on groundwater quality. It is
expected an analytical model can be utilized for the leachfield,
swale and soil pile areas.
EPA will make the decision as to whether any or all of the individual
leachfields and the soil pile and swale will require removal during
the design phase of this project. For costing purposes, a cost
analysis was performed for a number of possihle scenarios of source
area removal associated with all known or potential source areas
associated with the Tinkhams site (see table 17).
~.9nagement of Migration Alternatives
MOM - 1
No Action (with monitoring)
This alter.native involves a long-term monitoring effort to assess
off.site rnigration of contaminants and any subsequent impacts which
-------
T,2.:L~ l~,
;:,:,~S~~;T h'J~,iH h\,:',~YSIS FO~
r ~,:.: ;:., :: ~ '< ~ ~,T 0 F
($ x 1000)
/~: G~;" T I O~; A~ TE R:;,:',i IVE S
   ~WM-2B 
  Mor~-2A ADDITIONAL CARBON 
  AIR STRIPPING/ .TREAn:£NT WITH /10M-3
  CARSON TREATMENT GROUNDh'ATER PRETREATr-:£NT
  WITH SURFACE DISCHARGE h'ITH DISCHARGE
 NO ACTION DISCHARGE (SOIL FLUSHING) TO POTW
CAP IT AL COST $30 $2,040 $2,400 $1,830
OPERA TI ON & 241 (l-4 yrs) 560 600 540
r'~A I ~iTEt,ANCE 60 (5-30)   
CUSTS    
YEARS OF 30y rs 5yrs 5yrs Syrs
C?ERATION    
PRESENT h'ORTH 1,140 4,160 4,610 3,871"
-------
~;'.B~E 17
Co s t A q 1 Y s i s for So i 1 Vol um e
linkha~ Garage Site
    A. Capital Costs  
    ($ x 1,000)   
Description Soil SC-2A SC-2B 5C-2C 5C-3 SC-4
Source Area Vol~me Aeration Soilwash Composting Incinera- RCRA
  (yd )      tion Landfill
A. Garage Area        
only  1U,800 2,170 3,190 3,820 640 640
B. Garage SwalL,        
Soil Pi 1 e with        
no leachfields 12,500 2,370 3 , 4.~0 4,170 700 700
C. Garage Swale,        
Soil Pile with        
Leachfields        
I/J, K/L,G 19,3UO 3,070 4,490 5,390 900 900
D. Garage Swa1e,        
Soi 1 Pile with        
Leachfields        
1/ J, K/ L, G,        
M/N  22,000 3,320 4,850 5,820 970 970
E. Garage Swale,        
So i 1 Pile with        
Leachfields        
I/J, K/L, G,        
M/N, A 23,100 3,420 4,990 5,900 1 ,000 1,000
F. Garage Swale,        
50i 1 Pile and        
-------
    :kSLE 17 (Contin~ed)  
   B. Operation and Maintenance Cost  
    (S xl. 000)   
Description  Soil S C - 2A SC-2B SC-2C SC-3 SC-4
Source Area  Vol~me Aeration Soilwash Composting Incinera- RCRt..
   (yd )    tion Landfill
A. Same as above 10.800 790 490 350 17.640 4,700
B. Same as above 12.500 920 570 400 20,420 5.440
C. Same as above 19.300 1.420 880 620 31.520 8,400
D. Same as above 22,000 1,610 1,000 700 35,930 9.580
E.-Same as above 23.100 1,700 1,050 740 37,730 10,060
F. Same as above 30.800 2.260 1,400 990 50.310 13,410
   C. Present Worth Costs  
    ($ x 1,000)   
A. Same as above 10 .800 3,550 4,040 4.420 18,280 5.340
B. Same as above 12.500 3,960 4.460 4,860 21,110 11,480
C. Same as above 19.300 5,530 6.010 6.490 32.420 9,300
D. Sa~e as above 22.000 6,110 6.580 7,05U 36.900 10.550
E. Same as above 23,100 6.360 6.810 7,280 38.730 11,050
 .. 30.800 7.970 8.340 8.820 51,490 14.590
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shoul~ proceed to a total volatile organic (TVO) target level of 1 ppM
in contaMinated soils from the field behind the gar~]e. The 1 ppm of
TVO corresponns to the lateral extent of contamination in
surficial nedia. Vertically, excavation will proceen to the seasonal
low water tahle. This corresponds to approximately 10,800 cuhic
yards of contaminated soil to he excavated. The 1 ppm houndary
is believed to represent the approximate extent of detectable
contamination.
The 1 ppm cleanup target level is considered appropriate for two
reasons. First, at 100 ppm the ingestion risk associated with this
area has been conservatively estimated to be 1.9xlO-4. This
level is not considered appropriate to provide adequate protection
of public health and welfare and the environment. At 10
pprn, the estimated lifetime cancer risk is 1.9xlO-5 which
falls within the target risK range for reme~iation. However,
by removing contaminated soil to 1 ppm, it is expected that
the groundwater remediation time will be reduced, in addition
to providing greater protection to public health and welfare
and the environment. Furthermore,the shorter time required for
groundwater remediation is consistent with EPA's policy of
implementing rapid cleanups of all current and potential drinKing
water. Finally, based on annual operation and maintenance costs
associated with each management of migration alternative (see
Table 16), this shortened groundwater treatment time is likely
to result in a more cost-effective groundwater clean-up.
The need for excavation and treatment of the leachfields, the soil pile
and the swale has yet to be determined. A significant direct contact/
ingestion risk is not attributed to each of these source areas. .
Excavation and treatment of contaminated soils will proceed based
upon an evaluation of the potential for individual source areas
to contribute to groundwater contamination. This will require
the use of an analytical-model capahle of predicting the impacts
of these individual source areas on groundwater quality. It is
expected an analytical model can be utilized for the leachfield,
swale and soil pile areas.
EPA will make the decision as to whether any or all of the individual
leachfields and the soil pile and swale will require removal during
the design phase of this project. ~or costing purposes, a cost
analysis was performed for a number of possihle scenarios of source
area removal associated with all known or potential source areas
associated with the Tinkhams site (see table 17).
~.9..!2.9iLernent of Migration Alternatives
MOM - 1
No Action (with monitoring)
This alternative involves a long-term monitoring effort to assess
offsite migration of contaminants and any suhsequent impacts which
-------
T ,2,2 L. ~ l ~.
~;,~S~~;T \.,'J;,irl A~;:"~ YSIS F02
r~,'::;:',:;::",::~\T OF
($ x 1000)
r~:G~;' T IO~i A~ TER~;,!;,iI V[S
   ~~OM-2B 
  Mor~- 2A ADOITIONAL CARBON 
  AIR STRIPPING/ .TREATr-1ENT WITH t~OM-3
  CARSON TREATMENT GROUNJh'ATER PRETREA H~E NT
  WITH SURFACE DISCHARGE h'ITH D!SCHARG~
 NO ACTION DISCHARGE (SOIL FLUSHING) TO paTh'
CAP IT AL COST $30 $2,040 $2,400 $1,830
OPERATION & 241 (1-4 yrs) 560 600 540
f.:AI:iTEr,ANCE 60 (5-30)   
CuSTS    
YEARS OF 30y rs 5yrs 5yrs 5yrs
C?£RATION    
PRESENT h'ORTH 1,140 4,160 4,670 3,871"
-------
-:-;'.8~E 17
CDS t A r:a 1 y s i s for 50 i 1 Vol um e
linkhaCi Garage Site
    A. Capital Costs  
    ($ x ItOOO)   
Description 50il SC-2A SC-2B SC-2C SC-3 SC-4
Source Area Vol~me Aeration Soilwash Compo sting  Incinera- RCRA
  (yd )      tion Landfi 11
A. Garage Area        
only  lUt800 2t170 3t190 3t820 640 640
B. Garage Swall.t        
Soil Pi 1 e with        
no leachfields 12t500 2t370 3 t 4.~0 4,170 700 700
C. Garage Swalet        
Soil Pile with        
Leachfields        
I/J, K/L,G 19t3UO 3t070 4,490 5,390 900 900
D. Garage Swale,        
So i 1 Pile with        
Leachfields        
I jJ, K/ L, G,        
M/N  22tOOO 3,32U 4t850 5,820 970 970
E. Garage Swale,        
Soi 1 Pile with        
Leachfields        
I/J, K/L, G,        
MIN, A 23,10U 3,420 4t990 5t900 ItOOO 1,000
F. Garage S'n'alet        
So i 1 Pile and        
-------
    TASLE 17 (Contin~ed)  
   B. Operation and Maintenance Cost  
    ($ x 1,000)   
Descrip':.ion  Soil SC-2A SC - 2B SC-2C SC-3 SC-4
Source Area  Vo1~me Aeration Soi 1wash Composting Incinera- RCRA
   (yd )    tion Landfi 11
A. Same as above 10,800 790 490 350 17,640 4,700
B. Same as above 12,500 920 570 400 20,420 5,440
C. Same as above 19,300 1,420 880 620 31,520 8,400
D. Same as above 22,000 1,610 1,000 700 35,930 9,580
E.-Same as above 23,100 1,700 1,050 740 37,730 10,060
F. Same as above 30,800 2,260 1,400 990 50,310 13,410
    C. Present Worth Costs  
     ($ x 1,000)   
A. Same as above 10,800 3,550 4,040 4,420 18,280 5,340
B. Same as above 12,500 3,960 4,460 4,860 21,110 11 ,480
C. Same as above 19,300 5,530 6,010 6,490 32,420 9,300
D. Sai71e as above 22,000 6,110 6,580 7,05U 36,900 10,550
E. Same as above 23,100 6,360 6,810 7,280 38,730 11,050
-------
may result. If ariverse im?acts occu~, cor~ective action would
need to he taken. G~oundwater monitoring will entail evaluating
bac~grounn water quality and the water quality leaving the site.
Under the no-action response, two additional monitoring wells
would need to be installed downgradient of FW-17 to monitor
groundwater quality flowing offsite in the vicinity of the Unnamed
Trihutary. These wells will form a cluster with one well in
overburden and one well in bedrock. Additionally, residential
wells which continue to be used for drinking water purposes along
Ross Drive, the Tinkham Realty Company and one ?rivate residence
onslte to the immediate east of the realty company, will need to
be monitoren.
Sampling and analysis of all these wells would he connucted until
the potential threat is eliminated (Le. contaminants in grounn-
water meet the remedial objectives set forth). The sampling results
will be evaluated in order to estimate plume migration and dispersion.
Migration of contaminants into the Unnamed Tributary and/or Beaver
Brook would also have to be monitored on a quarterly basis. Exact
monitoring and sampling and analysis requirements will be determined
d u ring des i 9 n .
In terms of the 300.6~(h)(2){iii) criteria, the reliability of the
no ~ction alternative is ranked medium. The operation and
maintenance consists of monitoring to detect migration of
contaminants away from the source areas as well as those
migrating offsite. These activities will not be difficult to
implement and are expected to provide reliable information
concerning contaminant levels. The implementability and constr\lct-
ability of the no action alternative is high since the only
construction involven is the drilling and installation of two wells.
The no action alternative entails allowing natural mechanisms to
degrade or disperse the contaminants to below detectable or harmful
levels over time. Several possible methods to estimate the
natural ~enuction of groundwater contamination with time at
this site have been attempten (see appendix C of the FS). using
Using Wells FS-II behind Tin~hans garage, downgradient of the
source area, and ERT-06, locaten within the Woodland village
Condominium compl(~x, natur.al atl:(~r1Uation has heen estimated (through
(through regression analysis of sampling nata) to require 10 years
and 18 years, respectively. If the removal and treatment of the
source areas above the seasonal low water table are taken into
consineration, these times will he reduced.
Consider.ing the screening criteria under 300.68{h){2)(iv) of the NCP,
the no action (with monitoring) alternative does not cOl11ply with
applicahle or relevant and appropriate Federal puhlic health and
environmenti'\l requirements. Specific.:'llly, it is not in'coll11?1i.'lnce
with RCRA Part 264 Subpart F (Groundwater Protection), which
-------
requires compliance with a grolJndwater protection standar~. The
Agency has deternined that the proposed target levels for PCE and
TCE are equivalent to setting the groundwater protection standards
at Alternate Concentration Levels (ACLs). The no ~ction alternative
does not comply with the groundwater protection standard.
Contaminants have already migrated downgradient or away from their
point of disposal. Continued contaminant migration into the wetlands
will result in this alternative being out of compliance with
Executive Order llg90 and the Fish and wildlife Coordination Act.
This alternative will not effectively prevent, mitigate, or
minimize threats to and provide adequate protection of public
health and welfare and the environment as evaluated under 300.68
(h)(2)(iv) and as required under 300.~8(i) of the NCP.
The potential adverse effects from this alternative considerably
outweigh the probable benefits. If left unremedied, the aquifer
would remain unusable for a significant length of time. Worst case
monitoring well data indicates a 10-2 cancer risk from the most
contaminated wells onsite. In addition, the contaminated groundwater
would continue to discharge to wetlands and surface water bodies.
There are no benefits to local and transient populations with the
no-action alternative.
In the long term, the level of contamination in the groundwater will
decrease slowly. The primary long-term adverse effect is the potential
offsite migration of contaminated groundwater to drinking water wells
in use along Ross Drive. Additionally, the possihility of future
development on site exists. Contaminated groundwater may be utilized
for drinking water purposes if residential drinking water wells are
installed unknowingly. -
MOM - 2
Removal/Extraction and 50il Flushing with Onsite Treatment
MOM- 2A Air Stripping/Filtration/Carbon Adsorption wit~
Discharge to UnnaMed Tributary or Reaver Rrook.
This remedial alternative entails extracting contaminated groundwater
froln both the overburcten and bedrock aquifers, treating it onsite
using air stripping, filtration and carbon adsorption and discharging
it to the Unnamed Tributary onsite or to Reaver Brook offsite. Air
stripping will he preceeded by aeration an~ coagulation/precipitation
for metals removal and followed by neutralization. As evaluated
under 300.68(h)(2)(iii), technically this alternative is considered
to be constructable, implementahle and reliable. It consists
of unit treatment processes with proven performance records
in the treatment of wastewater containing 'netals and organics.
Aeration to oxidize metals has been used for years in municipal
water treatment plants. Air stripping is a proven technology for
r~moval of volatile organics and has been used at nume~ous hazardous
waste remediation sites. \~ith an air flow to water ratio of 150 to
1 (volume basis), removal of volatile organics in the gS to qg percen
range are possible.
-------
Table C-l, in Appendix C of the FS, shows that requir~ments for
orQ3nic compounds are not overly restrictive and should be
achievable by the combined use of air stripping and activated
carbon.
Under the terms of 300.~8(h)(2)(iv) of the NCP, this alternative.
is expected to attain applicahle or relevant and appropriate
Federal public health and envirJnmental requirements. Specifically,
the treatment and control of contaminated groundwater satisfies
RCRA Part 204 Subpart F (Groundwater Protection) and EPA's
Groundwater Protection Strategy by cleaning-up the aquifer
to the target levels in a reasonable time frame. The transport
of spent carhon or sludges offsite complies with RCRA Parts 262 and
203 and DOT 49 CFR 171-179 and 387 for transport of hazardous
material. The discharge from the air stripper will be designed
to meet standards set by national A~bient Air Quality via
vapor phase carbon adsorption. Additionally, dischargp to
the stream will he in compliance with National Pollution
Discharge Elimination System requirements. The water discharged
to the surface watet would be required to meet the water
criteria stated in the newest edition of the White Book
(1985). The new criteria entails using water hardness calculations
for setting limits. Hardness values of 20 ppm are used for
the 1985 criteria.
MOM - 28 Air Stripping/Filtration/Carbon Adsorption with
Discharge to the Groundwater
This alternative entails extracting contaminated groundwater from,
both the overhurden and bedrock aquifers, treating it onsite using
air stripping, filtration, and carbon adsorption and discharging it
to the groundwater in the field behind the garage. This alternative
is essentially the same as MOM-2A except that significantly more
carbon will he used. (Refer to MOM-2A for a description of the
groundwater removal scheme and subsequent treatment processes).
8f.fluent criteria for discharge to the groundwater will need to
meet MCLs for drin~ing water established by u.s. EPA because of
the potential for contaminants to migrate to wells still in use
for ~rinking water purposes. Drinking water regulations are ~ore
stri~gent than NPDES criteria for discharging into the Unnamed
Tributary or Reaver Brook.
The evaluation in terms of engineering implementation reliability
and constructahility (300.68(h)(2)(iii)), indicates that this
this alternative will utilize more carhon than in alternative
MOM-2A to achieve an effluent which meets drinking water quality
requir(~;n(~nts. The reliability of alternative MOM-2R is as
high as the Mm.1-2A alternative. The treatJ'1ent effluent will be
discharged to the ground using a recharge hed.
Applicahle or relevant and appropriate Federal public health and
environmental r8quirements as evaluated under 300.~8(h)(2)(iv),
indicate that this alternative attains RCRA Part 264 Subpart F
(Groundwater Protection) and EPA's Groundwater Protection Strategy.
-------
The transportation of spent carhon oi sludges offsite will he
designerl to comply with RCRA Parts 262 and 263 and DOT 49 CFR 171-
179 and 387 for transport of hazarjous ~aterial. The discharge
from the air stripper will be designed to meet applicable air
standards.
with both MOM-2A and MOM-2B altArnatives, the beneficial effects
substantially outwAigh the adverse effects as evaluated according
to 300.68(h)(2)(vi). The short-term advantage is that the potential
for the offsite migration of contaminated groundwater to the
surrounding areas along Ross Drive is mitigated. The long-term
benefits to the public health are twofold: (1) exposure from
contaminated groundwater onsite is expected to reach an
acceptable level within an estimated 5 years with treatment;
and (2) as discharge to the wetlands and the Unnaned Tributary
from contaminated groundwater is eliminated, the exposure
potential to local, transient and distant populations will
be measurably reduced.
There are no uncontrollable adverse effects from this alternative in
either the short-term or the long-term, and therefore it was ranked
high for mitigating public health impacts. with both alternatives,
the contamination that is presently occurring in the wetlands and
Unna~ed Tributary will be minimized. The reduction of contamination
in the groundwater to acceptable levels will occur relatively rapidly.
The extraction of groundwater and its potential impact on the
wetlands will be monitored to ensure that no detrimental effects
occur.
Since the treatment of volatile organic compounds emissions for the
air stripper will be treated, the adverse impacts that could result
from this are minimized. The discharge to the Unnamed Tributary
as described under alternative MOM-2A will be set according NPDES
re~uirements. If the treatment design selected is the one which
includes discharge to the groundwat~r, as under alternative MOM-2B,
t~e effluent will meet Drinking Water Standards.
MOM - 3 Offsite Treatment at POTW with Onsite Treatment
This alternative entails extracting contaminated groundwater from
the overburden and bedrock aquifers, potentially pretreating it onsite
with air striQQing, and transporting it offsite via a pipeline
to the local POTW (Derry Wastewater Treatment Plant) for final
tC8atment. Air stripping may be preceded by aeration and
coagulation/precipitation for metals and solids removal.
The treated effluent from the air stripping tower will be neutralized
and passed through a flow meter/reconler and an automatic sap1.pling
device. The '''''ater will be sa'npled periodically to assure
cornpli."\nce with the Town of Derry treatlnent plant's pretreatment
standards. (Plow will be discontinued if for any reason these
-------
stan~3rjs are not met). T~e effluent will then he collected in a
sumD, and pumped approximately one mile to the Derry, New Hampshire
\~ast8w~ter Treatment Plant. A 4 inch force main will be required.
(Domestic sewage will be mixed with the treated groundwater
prior to the water entering the Derry POTW).
The pipeline can he laid along existing resioential roadways
for most of its 5,000 foot length. The pipe will cross
Interstate Highway Route 93 by using one of two existing
24-inch sleeves under Route 93 adjacent to the treatment
plant. The sleeves were installeo at the time of highway
construction and were intended for use by the town of Londonderry
for a future sewer connection to the Derry treatment plant.
The force main will then be connected to the headworks of the
Derry treatment plant.
The Derry Wastewater Treatment Plant currently consists of a 1.2
million gallons per day (mgd) stabilization pono/aerated lagoon
treatment facility, which oischarges to the Merrimack River. Two new
aerateo lagoons and a grit chamber are presently under construction
and will increase the total treatment capacity to 4.2 mgd by the spring
of 1987. .
Effluent standards for the oischarge to the Derry Wastewater Treatment
facility consist of the local industrial pretreatment standards
estahlished by the Town of Derry and approved by the EPA. These
standards can be reviewed in table lR. In the event this
permit is revised with more stringent pretreatment standards,
any pretreatment of the ef.fluent leaving the Tinkham site will be
110dified to meet the new re4uirements.
The extraction of groundwater ann pretreatment envisioned unoer MOM-3
are proven technologies which were determineo to be highly implement-
ahle, reliahle and constructahle as evaluated accoroing to 300.68
(h)(2)(iii) of the NCP. The one technical concern associated with
MO~-3, as wAll as MOM-2, is the potential for frequent shutdown of the
treatment system for maintenance and servicing of equipment.
MOM-3 is expected to attain all applicable or appropriate and relevant
Federal requirements thereby meeting the criterion of 300.~~(h)(2)(iv).
This alternative is in comDliance with RCRA Parts 262, 263, and 264,
specificallj Subpart F (Groundwater Protection).
The effluent will meet the pretreatl1ent guidelines set forth by
the Town oE Derry for discharge to the POTW. The cleanup of the
groundwater is consistent with EPA's policy of seeking rapio cleanup
of all current and potential drinking water where it is cost-effective.
MOM ~ 3 is expecteo to achieve the remedial objectives set forth
at the Tinkham Garage site and effectively minilnize threats to,
and provide adequate protection of public health, welfare and the
environfnent as cvaluateo under 100.6~(h)(2)(iv) and is consistent with
the criteria for Selection of Remedy under 300.68(i)(I). The short-
-------
.: ~ 1-
I ,- ..\ - - ..:.',
? J 1 ~ J:: d '1 t ~ i '~i ta: i :J:1 S ! 0 r J i s c h a r 9 e tJ t h ~
To \"1"'1 a f ~) err j. r j e Iv H a f~ p S h ire - ~'J ~H r>
Cadmi U11  0.091 rng/l
Total Chromium 0.228 "
Copper   3.3d "
Lead   0.27 "
Nickel   0.12 "
Si 1 ver   0.072 "
Total Cyanide 0.324 II
Zinc   2.61 "
Arsenic  0.003 II
Iron   10.0 "
Sodium   500.0 II
Chlorides  500.0 II
j.1e rc u ry  0.048 "
j'1anganese  10.0 "
Sulfate  20.0 "
Sul fide  20.0 "
Sulfite  2.0 "
Reryll i urn  0.008 "
Boron   2.0 "
Selt=:niuiTI  0.054 "
Phenols  0.324 "
Total Toxic Organics 5.0 "
.,
r.,.
~
'4
-------
term puhlic health benefit from this alternative is that the exposure
potential from contaminants in the wetlands ann the Unnamed Tributary
will be rapioly reduceo as further migration of contaminated ground-
water to these areas is mitigated.
No short-term adverse effects are anticipated, but a long-term adverse
impAct is the possible breakage in the sewer li~e, extenrling from
the site to the Derry POTW. Distant populations are in danger if
this were to occur. However, the likelihood of this occurring is
negligihle because the best availahle engineering design and controls
will be employed.
MOM-2A, MOM-2B and MOM-3
Implementatio~ of MOM-2A, MOM-2B or MOM-3 will require
groundwater to be extracted using two existing, deep (300 feet),
be~rock wells already in place on site, LGAW and Ldsw.
Wells LGAW and LGSW are 6 inch diameter open rock boreholes. By
pumping wells LGAW and LGSW, two northeast/southwest orienteo
troughs of depression will be created as previously described.
This establishes control over the areas affecteo by contaminated
groundwater. Submersible pu~ps will be useo to extract the
water from these wells for treatment. In addition, a collection
trench will be installed downgradient of the source area in
the field southeast of the Tinkham Garage. The trench will he
approximately 300 feet long with a width of 4 feet and a depth to
berlrock. Groundwater will be pumped from a gravel filled sump
located in the lowest point of the trench. The estimated
pumping rates for LGAW and LGSW and the trench to be constructed
is 45gpn, 30gpm and 20gpm respectively. This corresponos to a
total estimated volume of groundwater to be extracted of 100
gpm or 144,000 gpd. This volume will be adjusted during
impl~mentation to maximize efficiency and/or to minimize
adverse environmental effects. The wetlands will be monitored
throughout the groundwater extraction process. If adverse
impacts on the watland are observeo, the pumping rate will
he reduceo.
80th, MOM-2 and MOM-3 will require a monitnring program to insure
grounnwater contamination control onsite and to insure contamination
is not migrating offsite. Additionally, a two well cluster (over- .
burden and henrock), will he installed downgradient of FW-I? to
monitor grounowater quality flowing offsite in the vicinity of the
UnnaMed T~ibutary. The exact extent of the contaminant plume south of
FW-l? is not fully characterizeo at this time.
Rcsioential wells in use along Ross Drive will be monitored until water
quality objectives citeo for groundwater are met onsite.
As specified under MOM-2A, MOM-2B and MOM-3, an estimated 5 years of
grou~~water treatment is anticipateo. This is a conservative estilnate
used to cost each of these alternatives; The 5 year cstilnate was
-------
baserl on the most conse~vative estimates for cleanup with no sou~ce
control action and anticipating frequent shutdown of the system
for n.aintenance and service. (Because all MOMs used the same
assumptions about pumping and treatment rates, this estimate did
not influence the selection of the appropriate management of
migration alternative). With the removal and treatment of the
the source areas above the seasonal low water table as specified,
it is anticipated that treatMent time will be reduced. For this
reason contaminated groundwater will be monitored during the
pumping and treating of groundwater according to the schedule to
be worked out during design phase.
Treatment of groundwater will cease upon achieving 5 ppb of PCE
and 5 ppb of TC~ in each well on site. Overall risk factors will
then be evaluated to ensure that adequate protection has been
achieved. In any event, at the end of two years from the
initiation of groundwater treatment, EPA will re-ev'aluate the
groundwater remedial objectives to determine if they are
achievable.
Costs for Management of Migration Alternatives
Capital, operation and maintenance and present worth cos~s for
management of migration alternatives are summarized on Table 19.
Detailed cost estimates are +50%, -30%. Supporting documentation
is available in Section 4 of the FS.
Selection of Remedy

Section 300.68 (i) of the National Contingency Plan (NCP) states the
appropriate extent of remedy shall be determined by the selection of
a cost-effective (i.e. the lowest cost alternative that is techno-
logically feasible and rAliable) remedial alternative that effectively
miti(Jates and minimizes threats to, and provides adequate protection
of, public health and welfare and the environment. Consistent
with the NCP, the following alternatives were not selected as an
appropriate extent of remedy:
Source Control
SC-l
(no-action)
This alternative does not meet remedial objectives and does not
attain or exceed applicable or relavent and appropriate Federal
public health and environmental requir8~ents. As such, it does
not effectively mitigate and rninilnize threats to, and provide
adequate protection of, public health and welfare and the
environme1lt. Un,jer 300.6~(i)(1) of the NCP, this alternative
may not be selected.
SC-3
(Excavation of Contaminated Soils and Offsite Incineration)
This alternative exceecis applicahle Federal publiC health and
-------
:ASL~ lS
~-'-("'-t'- 1''''''''-''
r ~. : ,) :. ,'I " \000':-\ I :i
';":~YSIS FO~
~'!.: ~~: S~ .,1.:: r,T OF
t.~::~;":IOt, A~ TEP':,.:.TI\'~S
($ x 10aa)
    1':OM-2B 
   P,J~~-2A ADOITIONAL CARBON 
   AIR STRIPPING/ TKEATr-:ENT WITH t':J~-3
   CARSON TREA Tt~ENT GP.OU:i~\-iA TER P?ET 2E/.. n~ENT
   WITH SURFACE DISCHARGE \.,'JTH DISCHhRG~
  I~J ACT I ON DISCHARGE (SOIL FLUSHING) TO POT\.J
CAPITAL COST  $30 $2.040 $2..400 $1,830
OFERATION & 241 (1-4 yrs) 560 600 540
I.~A I t, EI;f..t~CE 60 (5-30)   
CUSTS     
'YEARS OF  30y rs 5yrs 5yrs 5yrs
O?ERATION     
PRESEla \.iORTH  1,140 4.160 4,670 3.870
* 0&;: costs are per year
,.
-------
environmental requirements. However, in comparing this
alternative with SC-2 (Excavation of Contaminated 50ils
with Onsite Treatment) the public health and environmental
benefits from the two alternatives are the same, but the
cost of 5C-2 is lower. Therefore, this alternative w~s
eliminated under 300.08(i)(1) because it is not cost-effective
in comparison to 5C-2.
SC-4
(Excavation of Contaminated Soils and Offsite Disposal
at a RCRA Landfill)
This alternative was ruled out due to reliability. The long term
reliability of landfilling has not been proven. Additionally,
tne current Agency CERCLA policy is to select remedies that
destroy wastes and waste residues in order to provide long
term protection of public health and welfare and the environment.
5C-4 would not be consistent with this policy~

Furthermore, CERCLA Section 101(24) prohibits remedial actions
involving off-site storage, treatment, destruction or
secure disposition, unless such actions are determined
to be more costeffective than other remedial measures,
to create new disposal capacity in compliance with Subtitle
C of RCRA or to he necessary to protect public health
welfare or the environment. SC-4 does not meet any of
these criteria and therefore would not be an acceptable
remedy under ~lOl(24).
Management of Migration
~10M-l
(no-action)
This alternative does not attain or exceed applicable or relevant
and appropriate Federal public health and environmental requirements.
As such, it does not effectively mitigate and minimize threats to,
and provide adequate protection of, public health and welfare and
the environment. Under 300.68(i)(1) of the'NCP, this alternative
may not be selected.
i'1OM-2
(Removal/Extraction and Onsite Treatment)
nm1- 2A (oi scha rge to Tr i bu ta ry)
MOM-2R (Discharge to Groundwater)
Roth these alternatives were screened-out because of reliability
and cost-effectiveness in comparison to MOM-3 (discharge to POTW).
r 10 ~1- 2 .l\ and 2 R are bot h m 0 r e co s t 1 y t h a n ~-1 0 M - 3, w h i 1 e not pro v i n i n 9
significantly more protection to public health ann welfare and the
environlnent. Additionally, Mm1-3 is considered a more reliahle
alt'o:t-native than either ~'lOr1-2A or 28. The potential for frequent
shutdown for maintenance and service of the onsite groundwater
-------
treatment system exists for MOM-2A and 28. MOM-J will require
less frequent shutdown of the onsite pretreatment system hecause
the onsite pretreatment system (if implemented), is less complex.
Treatment will be completed at the Town of Derry, New Hampshire
p 0 T~v. Con s i s ten t wit h J 0 0 . f) 8 ( i )( 1) 0 f the N C P, a 1 t ern a t i v e s
2A ana 28 were not selected.
-------
RECOWISNDED ALTERN.l\TIVE
Consistent with 300.68(i) of the NCP, the remedial ohjectives set
and hased upon the evaluation of the RI, the alternatives
set forth within the FS and public comment, EPA has determined,
and the State of New Hampshire concurs, that the following
alternatives be implemented:
fo r t h ,
SOURCE CONTROL
(SC-2) Excavation of Contaminated 50ils with Onsite Treatment
This alternative is outlined in detail within the PS report and
summarized within the Alternatives Evaluation SeFtion of this
documen t. The implel11.e n ta t ion of SC- 2 wi 11 be as. fo llows:
- Treatability Studies are to be performed for the proposed
aeration, soil washing and composting technologies.
- approximately 10,800 yd3 (29,160 ft2 lateral extent) of
contaminated soil located behind the Tinkham's garage
is to be excavated and treated onsite by either aeration,
soil washing or composting. Of the approximately 10,800
cubic yards to be excavated, approximately 2,960 yd3
(8,000 ft2 lateral extent) is located within the wetland
in this area. During excavation of the wetland portion of
this source area best engineering practices will be employed
to minimize adverse impacts to the wetland. Additionally,
upon completing soil excav~tion in the wetland,
restoration activities will be implemented to speed
recovery of this area.
- Signs will be posted in the field area behind the Tinkham's
garage indicating this is a restricted area and a he~lth
hazard is present.
- removal of potential soil source areas in the Woodland Village
Condo'ninium complex (i.e., individual le.:=\chfields, soi 1 pile
ann swale) will be determined based on sampling during
the desi(Jn phase. If contamination is docUiflenterl in any
of the individual potential source areas, the need for re/noval
of the soils will be determined by its ability to
contaminate groundwater above the 5 ppb concentration
for PCE and TCE. Removal of a source area in the condominium
complex will consist of its entire confined volume.
If EPA determines that any of these potential source
areas do not require remediation based on this criterion
these areas will remain as they presently exist.
.
.;.
'\-
-------
- Tre~ted soils will ~e returned to the excavation locations
to be graded and revegetated comparable to present .site
conditions. Leachfields excavated will be reconstructed
to original design. Interi~ do~estic sewage disposal
measures will be provided if necessary during reconstruction.
Onsite soil tre~tment (aeration, soil washing or composting)
will ~roceed to a level that will be determined after the
pilot studies. This level will be based on technical feasibility,
reliability and cost-effectiveness. The level will be determined
consistent with the RCRA delisting proce~ures and the remedial
objSctives. At a minimum, soil will be treated to 1 ppm of
Total Volatile Organic compounds to be consistent with the
excavation criteria. It is anticipated that all three of the
proposed treatment technologies have the potential to achieve
this objective.
Selection of the specific technology (i.e. aeration, soil washing
or composting)
MA~AGEMENT of MIGRATION
(MOM-3 )
Removal/Extraction and nffsite Treatment at the Town of
Derry POTW which may be preceeded by on-site pretreatment,
with Monitoring .
- Removal of contaminate~ groundwater from the overbur~en and
bedrock aquifers through the use of two bedrock wells (LGSW
and LGAW), and a trench to be located behind Tinkham's garage.
- Extracted groundwater will he forwarded through the use
of a pump s ta t ion and force Hla into the Town of De rry
POT\v approximately 1 mile east of the site. Effluent
discharged from the site may be preceded by onsite pre-
treatment. The need for pretreatment will be determined
by EPA during design. This determination will be made to
ensure that effluent discharged from the site will
meet the local pretreatment regulations Eor the the
Town of Derry, New Hampshire POTW. If pretreatment
regulations are violated at anytiHle, effluent discharge
from the site will he terminated until those regulations
are met. Domestic sewage will be mixed with the
effluent prior to it entering the Derry POTW.
- Groundwater extraction will proceed for a two year
period from the date of implementation. At the end
of the' two year period an evalu.=ttion will be made hy
8PA to assess progress in meeting renedial objectives
for the cleanup of groundwater at the site. If steady
state conditions have been reached, and it is evident
remedial objectives are not achievahle, ~PA will
re-evaluate the objectiv~s and its remedial approach
to the Tinkham site.
-------
- Grounrlwater remediation will cease upon achieving
5 ppb of PCE and 5 ppb TCE in every onsite well
and in the trench proposed for construction behind
Tinkham's garage. Upon ahcieving 5 ppb for PCE and
TCE EPA will determine if water quality is protective
of puhlic health and welfare and the environment.
- Monitoring of wetlands onsite will be conducted to insure
no detrimental imp~cts from the extraction of groundwater
for treatment. If negative impacts are observed, the
rate of groundwater removal will be decreased to the
point wetlands onsite are not adversely impacted.
- Onsite and offsite monitoring will be implemented
consistent with RCRA S264.l00(d). Monitoring will
require the installation of a two well cluster
south of well FW-17 to fully characterize the extent
of contamination.
-------
OPERATION AND MAINTENANCE
Operation ann maintenance costs (O&M) are those required to ope~ate
and maintain the ~emedial action throughout its lifetime. This
activity ensu~es the lifetime effectiveness of the remedial
alternatives selected.
A range of capital, O&M and present worth costs for SC-2, are detailed
in table 20A, 20R and 20C.
The capital, O&M and present worth costs for MOM-3 specifically, are
detailed in tahle 21. ~
State Role
The state's role in this fede~al lead site is multfple. The state
reviews documents to determine if they are in compliance with
applicable state laws and provines comments on all EPA funded
stu~ies at the site. The state of New Hampshire concurs with
EPA's chosen remedy for the clean up of the Tinkham Garage
Site, locaten in Londonderry, New Hampshire. The State of New
,Hampshire will provide:
o 10 percent of the capital costs of the chosen remedy (5C-2
and MOM-3).
o 10 percent of the operation and maintenance costs for 5C-2
and MOM-3 throughout the remediation process.
o 10 percent of costs associated with the monitoring of
~esidential wells in use on site and off site for the
fi~st year.
o 100 percent of costs associated with monitoring of
~esidential wells in use on site and off site after
one year.
~
!~
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TABLE 20A
Recommended Alternative Cost Summary
Source Control Alternative - Aeration
INITIAL CAPITAL COSTS
Excavation
Material Handling/Preparation
Pretreatment System
Aeration System
Post-treatment System
Si~e Work
Onsite Architectural and
Electrical Work
Pilot Treatability Study
System
TOTAL INITIAL CAPITAL COST
OPERATIONS AND MAINTENANCE (O&M) COST
On-site Treatment System
Site Maintenance
Material Handling
Monitoring and Analysis
TOTAL ANNUAL O&M COSTS
PRESENT WORTH O&M COSTS
*TOTAL ALTERNATIVES COST
*Gased on 10.800 yd3 of soil.
$
60.000
434,000
420,000
475,000
129,000
94,000
266,000
180,000
$2,058,000
$ 648,000
90,000
56.000
80,000

$ 874,000
$1,520,000
$3,578,000
~
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TABLE 20B
Recommended Alternative Cost Summary
Source Control Alternative - Soil Washing
INITIAL CAPITAL COSTS
Excavation
Material Handling/Preparation
Pretreatment System
Soil Washing System
Post Treatment System
Leachate Recovery System
Si te Work
Onsite Architectural and
Electrical Work
Pilot Treatability Study
System
TOTAL INITIAL CAPITAL COST
OPERATIONS AND MAINTENANCE (O&M) COST
Onsite Treatment System
Site Maintenance
Material Handling
Monitoring and Analysis
TOTAL ANNUAL O&M COSTS
PRESENT WORK O&M COSTS
*TOTAL ALTERNATIVE COST
*Gased on 10.800 yd3 of soil.
$
60.000
434,000
420,000
502,000
629,000
440.000
94,000

266,000
260,000
$3,105,000
$ 340,000
80,000
72,000
70,000
$ 562,000
$ 978,000
-------
TABLE 20C
Recom~ended Alternative Cost Summary
Source Control Alternative - Composting
INITIAL CAPITAL COSTS
Excavation
Material Handling/Preparation
Pretreatment System
Compositing System
Post-treatment System
Site Work
Onsite Architectural and
Electrical Work
Pilot Treatability Study
System
TOTAL INITIAL CAPITAL COST
OPERATIONS AND MAINTENANCE (O&M) COST
Onsite Treatment System
Site Maintenance
Material Handling
Monitoring and Analysis
TOTAL ANNUAL O&M COSTS
PRESENT WORTH O&M COSTS
*TOT AL AL TEJ~ NA TI VE COST
*13ased on 10.800 yd 3 of soi 1.
. .
"
$
60,000
434,000
420,000
1,580,000 .
231,000
162,000
216,000
260,000

$3,363,000
$ 196,000
50,000
112,000
70,000

$ 428,000
$ 720,000
-------
Tf..SL~ 21
Reco~~ended Alternative Cost Summary
~cnagement of Migration Alternate - Offsite Treatment at POTW with
Onsite Air Stripping
. INITIAL CAPITAL COSTS
Groundwater Collection System
Aeration System
Pretreatment System
Sludge Dewatering System
Access Road and Site Work
Onsite Architecture and
Electrical Work
Groundwater Discharge System
.Carbon Adsorption System
Pilot Treatability Study
Sewer Connection Fee
$
108.000
164.000
330.000
244.000 .
19.000
315.000
135.000
205.000
100.000
210.000
TOTAL INITIAL CAPITAL COST
$1.830.000
OPERATIONS A~D MAINTENANCE (O&M) COST
Onsite Treatment System
Site Maintenance
Sludge Disposal
Effluent Disposal
Monitoring and Analysis
$ 296.000
41.000
69.000
84.000
50.000

$ 540.000
TOTAL ANNUAL O&M COSTS
P~ESENT WORTH O&M COSTS
$1.560.000
TOTAL ALTERr;ATIVES COST
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CONSISTENCY WITH OTHER ENVIRONMENTAL LAWS
Environmental Laws which are applicable or relevant and appropriate
to the selected source control and management of migration alternatives
at the Tinkham Garage site are:
- Resource Conservation and Recovery Act (RCRA)
- Clean Water Act
- Safe Drinking Water Act
- Clean Air .A.ct
- Executive Orner llQ90 (Protection of Wetlands)
- Executive Order 11988 (Ploonplain Management)
As specified within the Detailed Analysis of alternatives section,
both SC-2 and MOM-3 are expected to fully comply with the above
laws. The primary environmental law of concern at the Tinkham
Garage site is the Resource Conservation and Recovery Act (RCRA),
42 USC. ~6901, et seq. The proposed source control alternative
(SC-2) was reviewed for consistency with applicable RCRA technical
standards, 40 CFR ~ 264 Subpart G entitled Closure and Post-Closure,
Subpart L entitled Waste pilGS and Subpart N entitled Lannfills.
The RCRA closure regulations require either closure by removal of
waste, waste residues and contaminated subsoils, which is equivalent
to closure as a surface impoundment or waste pile (40CFR 264 Subpart
K, and L), or closure as a landfill by capping and appcopriate post
closure care (40 CFR 264 Subpart N). The source control remediation
will be equivalent to closure as a surface impoundment or waste
pile. The selected soil treatment levels will be demonstrated to
be technically equivalent to the RCRA delisting process.
The pilot studies will determine achievable treatment levels
that are capable of achieving the technical requirements of
the RCRA delisting process.
The excavation criteria of 1 ppm for PCE and TCE has been
determined to he consistent with the groundwater remediation
and protective of public health and the environment. The 1
ppm boundary approximately delineates the extent of known
conta,-nination.
A groundwater::-
monitor water
the effect of
quality.
monitoring prO
-------
Regarrling management of migration measures, the relevant federal
regulations are the RCRA Groundwater Protection requirements (40 CFR
264 Subpart F), the Clean Water Act and Safe Drinking Water Act.
The groundwater protection regulations require the setting of
groudwater protection standarns which must be protective of public
health and the environme~t. The target levels of PCE and TCE (5 ppb)
are site specific levels that t~e Agency has netermined will adequately
protect puhlic health and the envivonme~t. The remediation will
attempted to achieve these levels at all wells on site.
A groundwater monitoring system will be implemented to determine
the effectiveness of the grou~dwater recovery system.
The remediation of groundwater is consistent with the u.s. EPA Ground-
water Protection Strategy (GWPS), which classifies the aquifer at
Tinkham's as IIA (current usage by resicients along 'Ross Drive) ann
requires the restoration of these aquifers. This remediation program
would also be consistent with State of New Hampshire's groundwater
protection rules.
The tie-in of pretreated grou~dwater will he in compliance with the
applicable RCRA requirements. The POTW will receive pretreated
groundwater through a sewer that also serves as a domestic sewer,
so it will not be subject to the RCRA hazardous waste Management
require~ents for treatment, storage and disposal facilities (TSDF's).
The Clean Water Act sets forth the pretreat~ent requirements for the
Derry POTW for effluent leaving the Tinkham site. Prior to the
effluent leaving the Tinkham site it will be monitored to
insure compliance with the applicable pretreatment standards.
Additionally, SC-2 specifies that of the 10,800 cuhic yards of soil to
be removed in the g.,raeJe area, 2,960 cubic yards, corresponding to
8,000 square Eeet laterally is designated wetlands.
Consistent with Executive Order 11990, it is the determination of EPA
that no practicable alternative exists to 5C-2 that will effectively
and reliably prevent, mitigate or minimize threats to, and provide
aciequate protection of public health and welfare and the environme~t,
consistent with the remenial objectives set forth at the Tinkham site.
In implementing 5C-2 in the w~tlands, 011 practicable measures to
minil"i2e harm to the wetlonds which may result from the excavation will
be utilized. Furthermore, upon completion of 5C-2, restoration
activities will be implemented to effectively and practicably
rni~i,nize the length of the time required for this wetlands area
fulli recover. .
The rem 0 val 0 E con t a I n i n a t ion from the w G t 1 and and its sub s e que n t
rl)storation will result in the improvement of. its beneficial
value.
The Swale area identified for possihle remediation and located
within the woodland Village Condorninium complex exists within the
100 year Elooci plain associaterl wit~ the Unnamed Trihutary.
-------
Executiv8 Orner 11QS8 requires Federal agencies to reduce the
risk of flood loss, to minimize the impact of flooos on hUMan
safety, health ann welf~re, ~nd to restore and preserve the natural
and beneficia: values served by floonplains. The potential removal
of the swale is not anticipaten to have any detrimental impacts
upon the floorlplain.
-------
*SCHEDULF.:
Sign Record of Decision
- September 29, 1986
Project design, to include treat-
ahility stujies for SC-2,
additional field work on leach-
fields, soil pile and swale
and requirement for pretreatment
- November 1, 1986
Construction of on site soil
treatment facility
- Fall 1987
construction complete
- Summer
1988
Begin on site soil excavation
and treatment and construction of
onsite groundwater treatment
facility and flow system to
Derry POTW
- Winter 1988/1989
Begin groundwater extraction
and treat1nent with discharge
to De r ry POT~'J
- Fall 1989
EPA evaluates gronctwater treat-
ment for consistency with
t"1=1:l8Ilial ohject ives
- Fall 1991
-------
FUTURE ACTIONS
Future actions require several decisions and actions by the
U.S. EPA.
Pirst, EPA will decide upon the most appropriate technology
(i.e. aeration, soil washing or composting) for Source control.
This will be based on pilot studies to be conducted during
the design phase.
Second, EPA will decide upon the necessity of excavating and
treating the potentially contaminated soils associated with
the leachfields, the swale and the soil pile. This will be
based on field work and modeling conducted during design.
.
Third, EPA will decide upon the necessity of onsite pretreatment
prior to effluent being discharged from the Tinkham site to the
Town of Derry, New Hampshire POTW.

Fourth, an additional future action will require a re-evalu1tion
of groundwater remedial objectives by EPA. The re-evaluation will
take place at the end of two years of groundwater remediation
efforts. At that time a decision will be made as to whether
remedial objectives for groundwater are achievable.
Finally, upon achieving the groundwater remedial objective
of 5 ppb for PCE and TCE, a decision will ~e made by EPA to
determine if groundwater is of quality that adequately protects
public health and welfare and the environment.
The IJ.S. EPA does recommend that either the Town of Londonderry,
New Hampshire and/or the State of New Hampshire develope legisla-
tion capable of preventing the present and future use of the
on site aquifer. Existing groundwater protection and water supply
rules at the State level may be employed to assist in attaining
this objective. This restriction should be effective until
the aquifer on site has heen restored to levels protective of
public health and welfare and the environment.
$
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COM~UNITY RELATIONS
The Londonrlerry, New Hanpshire community first became interested
in the Tinkham Garage site in January -1983 when the tirinking water
wells servicing the Londonderry Green Apartment complex and
several residences along Mercury Drive were closeti. This
occurred when volatile organic compounds were discovered in
the water. A temporary source of water was provideti to affected
residents until November 1983, when a permanent waterline
from the neighboring town of Derry, New Hampshire was fully
installed. At the time, there was a high level of concern
in the site area over the health and safety impact of exposure
to and ingestion of contaminated water. These concerns have
dissipated largely because of the waterline installation and
successful use of a new, permanent waterline.
Some residents, however, remain concerned about the possibility
of contamination showing up in wells along Ross Drive that are
currently clean. EPA has stateti that, if the Ross Drive
wells show contamination, this might be considered an immminent
threat to public health and that, with emergency funds, EPA could
provide an alternate water supply for those residences.
In Octobe~ 1985, the Londonderry Green Apartments began to be
sold as condominiums. One month later, all of the units had
either been sold or were in the process of being soln. The
name of the development was changed to Woodland Village.
Wo041and village condominium owners have been and continue to
be concerned about their potential liability for the contaminated
soils and groundwater on their property. EPA has explained
that under EPA's Superfund program present site owners are
considered to be responsible parties. EPA attorneys have added
that EPA has tiiscretion, however, in deciding which parties to
pursue for recovery of cleanup costs.
A public informational meeting to describe the FS alt~rnatives
and to respond to citizens questions was held at the Londonderry
Junior High School in Londonderry, New Hampshire on Aug! st 14, 1986.
The meeting was we~l attended by citizens, local officials and
legal representatives of potentially responsible parties. On
~ugust 26, lq86 a public hearing was held at the same location
to record COlnrnents by any interested parties. Comments
were given by the First Congressional District Director of u.S.
Representative Bob Smith, the New Hampshire Water Supply and
Pollution Control Commission (NH~vS&PCC) and the Chainnan of the
New Hampshire Toxic Hazarjs Campaign. written comments were
received by the Cannons Four Sites Steering COITIll'1ittee, and past
Owners of the Londonderr.y Green Apartment Complex during the
remainder of the comment period. The formal, three week comment
1
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period to accept oral and written comment on the feasibility
sturly alternatives took place from August 15, 1986 to September
5, lq86. These comments and EPA's responses are included in
the attached responsiveness summary. ~n addition, the comments
are summarized below. Also included in the responsiveness
sUITI'o3ry is a section on remaining community concerns, which
summarizes questions the community raised during the RI/FS
process, but were not submitted as formal comments. The EPA
and State should be aware of these concerns as they prepare
to undertake remedial design and construction at the Tinkham
Garage site.
80th Representative Smith and the Administrator of the NHWS&PCC
urged a total and complete cleanup of the Tinkham Garage
site. The NHWS&PCC Administrator concurred with the conclusions
of EPA's Feasibility Study (FS) and, while Represe~tative
Smith did not state a preference for any particular remedial
alternatives, he did express his confidence with them.
The Chairman of the New Toxic Hazards Campaign raised several
questions regarding the remedial alternatives and stated that
she was dismayed that vacuum extraction was not considered as
a source control technology.
with regard to source control, the Cannons Four Sites Steering
Committee commented that the soil pile and leachfield areas
do not pose a significant risk to the public, and that access
to the area behind Tinkham's garage should be restricted. If
it is determined that soil remediation in the garage area is
needed, the Steering Committee favors in-situ aeration.
The Steering Committee also suggested that pumping groundwater
directly to the Derry wastewater treatment plant is their
recommended management of migration technique. The Canmittee
does not support air stripping or metal pretreatment.
The past owners of the Londonderry Green Apartment Complex
support source removal in the area behind Tinkham's garage,
which they believe is the major source of the site contamination.
They also suggest that EPA consider seriously the no-action
management of migration remedial alternative.
.
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TINKHAM GARAGE SITE
Londonderry, New Hampshire
RESPONSIVENESS SUMMARY
The U.S. Environmental Protection Agency (EPA) held a public comment period
from August 15, 1986 until September 5, 1986 for interested parties to
comment on EPA's July 31, 1986 dra~t Feasibility Study (FS) for the Tinkham
Garage site. The draft FS examines and evaluates methods for cleaning up
hazardous ~astes identified at the site.
A responsiveness summary is required by Superfund policy for the purpose of
providing EPA and the public with a summary of citizen comments and
concerns about the site, and EPA's responses to those concerns.
The community relations responsiveness summary for the Tinkham Garage site
in Londonderry, New Hampshire is divided into the following sections:
I.
Overview. This section lists the proposed remedial alternatives
as presented in EPA's draft FS and summarizes public reaction to
the alternatives.
II.
Background on Community Involvement and Concerns. This section
provides a brief history of community interest and concerns
regarding the Tinkham Garage site.
III.
Summary of the Major Comments Received during the Public Comment
Period and EPA Responses to these Comments. This section
categorizes both written and oral comments received from the
community, State officials, Federal officials, and potentially
responsible parties on the remedial alternatives.
to these comments are also provided.
EPA responses
-------
IV.
Remaining Concerns.
This section describes community concerns
raised during the public comment period that
Hampshire Vater Supply and Pollution Control
be a~are of as they prepare to undertake the
remedial Bction at the Tinkham Garage site.
EPA and the Ne~
Commission should
remedial design and
Attachment A is also included as part of this responsiveness summary.
It
identifies the community relations activities conducted by EPA during the
remedial response activities at the Tinkham Garage site.
.
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I.
RESPONSIVENESS SUMMARY OVERVIEV
A.
Remedial Alternatives as Proposed in the Draft FS
The draft FS describes several remedial alternatives that are judged by EPA
to be the most effective for dealing with the contamination found at the
Tinkham Garage site. The remedial alternatives are organized into two
categories: 1) source control, and 2) management of migration. The
purpose of source control remedial alternatives is to address areas of soil
contamination on the site. The purpose of the remedial alternatives for
management of migration is to address groundwater contamination on the
site.
EPA will select one source control remedial alternative and one
management of migration alternative. At the time of the public comment
period EPA had not indicated its preferred alternatives. A listing of the
two categories of the remedial alternatives is provided below.
1. Source Control Remedial Alternatives
There are four source control remedial alternatives designed to
address soil contamination on the site.
These alternatives are:
o
no action;
excavation of soil and onsite treatment;
excavation o( soil and offsite incineration; and
o
o
o
excavation of soil and offsite disposal in a RCRA landfill.
2. Management of Migration Remedial Alternatives
There are three management of migration remedial alternatives
designed to address groundwater contamination at the site. These
alternatives are:
o
no action;
removal/extraction and onsite air stripping
groundwater or the Unnamed Tributary; and
removal/extraction/onsite air stripping and
at a public wastewater treatment plant.
with discharge to
o
o
offsite treatment
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B.
Public Comments on the Remedial Alternatives
The five parties yho submitted formal comments to EPA during the three yeek
public comment period are: U.S. Representative Robert Smith (Ney Hampshire
District 1); Administrator of the Hazardous Vaste and Groundvater
Protection Division of the Nev Hampshire Vater Supply and Pollution Control
Commission (NHVS & PCC); Chairman of the Ney Hampshire Toxic Hazards
Campaign; Cannons Four Sites Steering Committee; and past ovners of the
Londonderry Green Apartment Complex.
Both Representative Smith and the NHVS & PCC urged EPA to 70nduct a total
and complete cleanup of the Tinkham Garage site. The NHVS & PCC concurred
vith the conclusions of EPA's FS and, vhile Representative Smith did not
state a preference for any particular remedial alternative, he did express
his confidence in them.
The Chairman of the Nev Hampshire Toxic Hazards Campaign raised several ques-
tions regarding the remedial alternatives and stated that she vas dismayed
that vacuum extraction yas not considered as a source control technology.
The Cannons Four Sites Steering Committee stated that, in it's opinion, the
soil pile and leachfield areas do not pose a significant risk to the public
and that access to the area behind Tinkham's garage should be restricted.
If it is det~rmined that sotl remediation in the garage area is needed, the
Steering Committee favors in-situ aeration.
The Steering Committee also.suggested that pumping groundvater directly to
the Derry vasteyater treatment plant should be the recommended management
of migration technique. The Committee does not support air stripping or
metals pretreatment as part of the remedial alternative involving the Derry
vastevater treatment plant.
The past oyners of the Londonderry Green Apartment
removal in the area behind Tinkham's garage, yhich
major source of the site contamination. They also
Complex support source
they believe i~ the
suggest that EPA
consider seriously the no-action management of migration remedial alternative.
-------
II.
BACKGROUND ON COKHUNITY INVOLVEKENT AND CONCERN
The Londonderry, Ne~ Hampshire community first became interested in the
Tinkham Garage site in January 1983 ~hen private residential drinking ~ater
~ells servicing the Woodland Village condominiums and several residences
along Mercury Drive ~ere closed due to the discovery of volatile organic
compounds in the ~ater.
Since then, community involvement and concern at the Tinkham Garage site
has focused primarily on the follo~ing issues:
o
health and safety effects of contaminated ~aterj and
liability of condominium o~ners.
o
A.
Health and Safety Effects of Contaminated Vater
EPA provided a temporary source of ~ater to residents with contaminated
~ells until November 1983 ~hen a permanent ~ater line from the neighboring
Town of Derry, New Hampshire was installed by NHWS & PCC.
At the time, there ~as a high level bf community concern about the health
and safety effects of exposure to and ingestion of contaminated ~ater.
These concerns have dissipated largely because of the installation and
successful use of the new permanent ~ater line.
L
Some residents, ho~ever, remain concerned about site contamination
spreading to wells along RQss Drive that are currently clean. EPA has
stated that if the Ross Drive wells sho~ signs of contamination (they are
being monitored regularly by EPA) the contamination might be considered an
imminent threat to public health and, with emergency funds, EPA could
provide an alternate ~ater supply for those residences.
B.
Liability of Condominimum Owners
In October 1985, the Londonderry Green Apartments began to be sold as
condominiums. One month later all of the units had either been sold or
-------
~ere in the process of being sold.
to Voodland Village.
The name of the development was changed
Voodland Village condominium o~ners have been and continue to be concerned
about their potential liability for the contaminated soils and ground ~ater
on their property. EPA has explained that under the Superfund statute,
present site o~ners fall ~ithin the legal definition of liable parties and
could be considered to be potentially responsible parties. EPA attorneys
have added that EPA has discretion in selecting parties to pursue for
recovery of cleanup costs. Present enforcement negotiations concerning the
site do not include individual condominium o~ners as responsible parties.
~
~
The community continues to be concerned about the spread of ground~ater
contamination to Ross Drive and the liability of condominium o~ners. These
issues have been raised repeatedly at public meetings and have received
considerable attention from EPA.
~
~
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III.
SUMMARY OF MAJOR COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
AND RESPONSES TO THE COMMENTS
Comments raised during the Tinkham Garage site public comment period are
summarized briefly b~low. The comment period was held from August 15, 1986
to September 5, 1986 to receive comments on the draft FS. Comments are
categorized by source of comments (e.g., the community, State officials,
Federal officials, and potential responsible parties). At the time of the
public comment period, EPA had not selected preferred alternatives for
source control or management of migration.
A.
Comments from the Community, State Officials, and Fede~al Officials
The Chairman of the New Hampshire
raised several concerns regarding
draft FS. After commenting, the
Toxic Hazards Campaign (the Campaign)
the remedial alternatives proposed in the
Chairman stated that none,of the
alternatives proposed by EPA would meet the new Superfund regulations as
set forth in legislation, currently pending in Congress.
Representative Smith and the New Hampshire Vater Supply and Pollution
Control Commission (NHVS & PCC) both stated that they preferred a total and
complete cleanup of the site. NHVS & PCC agreed with the conclusions of
EPA's draft FS while Representative Smith expressed his confidence in them
without stating a preferred remedial alternative.
1.
Source Control Remedial Alternatives
a.
Comment: The Campaign is concerned that, when EPA is excavating
soil or digging into water on the site, volatile compounds will
escape into the air. The Campaign asked if there would be a bubble
placed over the area to prevent this from occurring.
c
EPA Response: EPA does not intend to place a bubble over the site
to prevent air emissions from occurring. If at any time air
emissions exceed acceptable levels, soil processing will be
terminated and re-evaluated by EPA.
-------
b.
The Campaign made reference to the Verona site in the
Comment:
midwest where a vacuum extraction system was used to remove
volatile compounds from the soil without disturbing it. The
Campaign asked why such a system was not considered for the Tinkham
Garage site.
EPA Response:
Tinkham Garage
alternatives.
A vacuum extraction system was considered at the
site and was eliminated in the initial screening of
Please refer to Section 3 of the draft FS.
In-situ
aeration was eliminated because of the following reasons:
o
the low permeabilities associated with the contaminated soils at
the site;
o
the high water table at the site that could cause operational
problems of the treatment system; and
o
the difficulties in controlling air emissions.
c.
Comment:
The Campaign was concerned that, for aeration and
composting, carbon will not remove some of the chemicals, such as
acetone and tetrahydrofuran, from the soil and the air.
EPA Response: Carbon is not used to remove contaminants from the
soil in aeration or composting. Soil sampling results indicate
that currently, these compounds are either present in very low
levels in the soil source areas or not present at all.
Collected
air emissions will be passed through a vapor phase carbon
adsorption unit to adsorb any acetone and tetrahydrofuran which
might be admitted into the air.
:;
d.
Comment: The Campaign is concerned about the ability to stop the
composting process should the heat cause an open fire, and
questioned the possibility of the process generating enough heat to
release the volatile compounds from the soil.
-------
EPA Response: The heat generated by the composting process is not
of sufficient temperature to result in an open fire. The heat and
microbial action viII result in the breakdovn and release of
volatile compounds from the soil. -
e.
Comment: The Campaign is concerned about air pollution, after soil
vashing, in the drying process.
EPA Response: Soil vashing viII take place in an enclosed
structure. This viII limit air emissions. If any air emissions
did occur during the soil vashing they vould be controlled by
implementing engineering controls. ~
f.
Comment: The Campaign asked, if source control alternative 3 vere
chosen, vould all or part of the soil be disposed at an offsite
incinerator.
EPA Response: The ansver is both. Certain portions of soil may be
so small or large in volume that they may not be suitable for
incineration. This soil may be sent to a landfill rather than
incinerated.
g.
Comment: The Campaign stated that it vould be unfair to take vaste
from one backyard and put it in another, as suggested in source
control alternative 4.
EPA Response: EPA's policy is to pursue response actions that use
treatment, reuse, or recycling rather than land disposal to the
greatest extent practicable. Vhere remedial measures include
offsite storage, treatment, destruction or secure disposition, such
measures must be more cost-effective than other remedial measures,
create nev disposal capacity in compliance vith Subtitle C"of RCRA,
or be necessary to protect public health, velfare or the
environment from a present or potential risk vhich may be
by further exposure to substances.
created
~
~
(
I
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2.
Management of Migration Remedial Alternatives
a.
Commen t :
The Campaign is concerned that the carbon filter proposed
for the groundyater removal/extraction and on-site air stripping
system ~ill not remove all of the contaminants and that the air
leaving the system will not be clean. The Campaign also stated
that water discharged to the ground has to conform to state
groundwater permitting lays and be of drinkable quality.
EPA Response: The groundwater treatment systems will be designed
to be capable of removing the contaminants to safe levels for
discharge to surface water or to groundwater.
can and will be controlled. These groundwater
will be designed to meet Federal and State air
standards.
The air emissions
treatment systems
and water treatment
3.
General Comments
a.
Comment: The NHVS & PCC stated that it is in agreement with the
conclusions described in the RI/FS, and is committed to a total and
complete cleanup of the site.
EPA Response: It is EPA's intent to select the appropriate extent
of remedy from among the alternatives that will achieve adequate
protection of public health, welfare and the environment.
b.
Commen t :
U.S. Repr~sentative Robert Smith submitted that he
supports moving forward with the Tinkham Garage site cleanup on a
positive, fast track. He stated that the success of cleaning up
the Tinkham Garage site will depend on safe and permanent solutions
and the ability to incinerate, neutralize, or otherwise totally
destroy hazardous substances in the soil and groundwater on a
permanent basis. He also urged EPA to continue to monitor closely
the wells on Ross Drive.
-------
EPA Response:
Consistent ~ith EPA policy, EPA ~ill seek a rapid
site cleanup. Destructive or other advanced, innovative, or
alternative technologies have been considered ~here appropriate.
EPA's selected remedy ~ill include both onsite and offsite long
term ground~ater monitoring.
B.
Comments from Potentially Responsible Parties
Complex, no~ called ~oodland Village
parties are summarized belo~.
the Cannons Four Sites Steering
of the Londonderry Green Apartment
Condominiums. Comments from these t~o
Detailed comments ~ere received from
Committee and from the former o~ners
Comments from Cannons Four Sites Steering Committee
The Cannons Four Sites Steering Committee organized its comments in three
sections:
1) source control remedial alternatives; 2) management of
migration remedial alternatives; and 3) the endangerment assessment.
follo~ing major comments and recommendations ~ere made.
The
1.
Source Control Remedial Alternatives
a.
Commen t :
The soil ~ile and leachfield areas are currently covered
and pose no significant risk to the public.
G
EPA Response: Lea~hing of contaminants
the soil pile and leachfield areas is a
health and ~elfare and the environment.
into the ground ~ater from
potential threat to public
Leaching of contaminants
has occurred in the past and can occur in the future. These areas
~ill be representatively sampled during the remedial design and
potential remediation ~ill be evaluated in light of the remedial
objectives for ground~ater. ~
))
-------
b.
Comment: The methodology used to estimate the
contaminated soil is not supported by the data
Field Investigation Team (FIT) report, the RI,
extent and volume of
generated in the
or the draft FS.
EPA Response:
EPA believes that the estimate of the extent and
volume of contaminated soil in the field behind the garage is based
on appropriate data. Soils in the leachfields, soil pile and svale
areas viII be sampled as a future action at the Tinkham site. Any
potential excavation viII proceed according to the defined lateral
and vertical extent of the soil contamination revealed by that
sampling in combination vith current data.
c.
Comment:
Access to the area behind Tinkham's Garage should be
restricted. If it is determined after further study that soil
remediation is required, the most reasonable source control
alternative is in-situ aeration.
EPA Response: The Tinkham garage area is private property. Access
to this area is restricted by the present land ovner~ EPA viII
place signs in the area stating that it presents a potential health
risk and that access is restricted.
EPA disagrees that'the most reasonable alternative is in-situ
aeration for the folloving reasons:
o
The fluctuating vater table, vhich can frequently rise above tpe
ground surface, ,viII cause operational problems;
~
o
The soils are composed of fine material vith lov permeability
vhich results in restricting the effective area over vhich the
treatment can be conducted; and
o
In-situ aeration promotes air emissions vhich are difficult to
control.
-------
~
2.
d.
Comment:
Removal of contaminated soils offsite to a hazardous
vaste landfill or incinerator should be removed from consideration
as a remedial alternative since it is is very costly compared to
other techniques proposed in the draft FS.
EPA Response:
EPA does not base its screening of alternatives
solely on cost.
See 300.68 (f) through (i) of the National
Contingency Plan (NCP). Consistent vith the NCP, this alternative
vas retained for consideration as a remedial alternative to be
considered for selection.
e.
Commen t :
The CLP data collected and used to chara~terize the type
and level of contamination at the site vas referred to as
unvalidated.
EPA Responses: At the time the draft FS vas prepared, not all data
had been validated. Currently, all CLP data has been validated.
All data used to reach the conclusions stated in the Record of
Decision has been validated.
Management of Migration Remedial Alternatives
a.
Comment: The methodology used to interpret the groundvater
constituent data (such as metals and organics).and establish
average and maximum values is not valid.
EPA Response: EPA believes the methodology employ,ed is valid.
unconsolidated aquifer and veathered bedrock aquifers are
hydraulically connected. It is common engineering practice to
evaluate treatment alternatives utilizing vorst case as veIl as
average values. A design assessment of contaminant concentrations
in groundvater viII be completed during the design phase.
The
b.
If it is determined that groundvater from the tvo
Commen t :
existing production veIls requires remediation, the most
appropriate technique is pumping directly to the Derry vastevater
-------
3.
treatment plant. Metals pretreatment is not needed based on a
reviev of metal data and Derry's pretreatment ordinance.
Air-stripping pretreatment is not needed since the majority of
organics in the ground vater are amenable to biological treatment.
EPA Response:
Effluent discharge leaving the Tinkham site viII be
required to meet local pretreatment regulations for the Derry, Nev
Hampshire privately-ovned treatment vorks (POTV). The need for
pretreatment viII be determined during design and viII be based on
maximum concentrations of contaminants present and the dilution of
the contaminants vith extracted groundvater.
c.
Comment: It is not necessary to use a soil flushing technique in
the area of Tinkham's garage since source control remediation will
effectively address over 90 percent of the organics in the area.
EPA Response: EPA viII not implement soil flushing in conjunction
vith the selected management of migration alternative.
The Endangerment Assessment
a.
Comment:
There is no basis for future remediation of groundvater
because it is not & source of drinking vater.
EFA Response: The potential exists for groundvater to migrate
tovard residential ,drinking vater wells. This is documented in the
Record of Decision and substantiated by water level measurements
taken by EPA both onsite and along Ross Drive (see Attachment B).
These measurements shov a hydraulic gradient in the bedrock aquifer
at the site sloping toward the domestic supply veIls along Ross
Drive, vhich are currently draving on this aquifer.
Consistent vith EPA policy, groundvater should be protected for its
highest benefit and purpose. Superfund's implementation of the EPA
Groundwater Protection Strategy viII seek rapid clean ups of all
-------
Q
~
h
current and potential drinking water where it is cost-effective to
do so. Moreover, the NCP requires selection of remedies tfiat are
applicable or relevant and appropriate. The No Action alternative
for groundwater remediation does not comply with the requirements
of 40 CFR 264 Subpart F (Ground ~ater Protection), which are
applicable and relevant requirements for this site.
Finally, neither EPA, the State
Londonderry has the legislative
of New Hampshire, nor the Town of

authority to restrict ground vater

use nov or in the future at the Tinkham site. This is a high
~
growth area and future development of land on site has been
proposed.
EPA believes that this reason, in addition to the
reasons outlined above, requires selection of a management of
migration alternative that effectively mitigates and minimizes
threats to and provides adequate protection of public health,
welfare and the environment.
b.
Comment: Two of the three scenarios developed to determine the
magnitude of risk associated with soil contamination are based on
the highly unrealistic premise that children have access to soil at
depths greater than one foot below the surface. In the absence of
additional analytical data, no quantification of risk is possible
either for the soil pile or the leachfields.
EPA Response: Risk estimates presented in the Endangerment
Assessment are based on the possibility that children can gain
access to contaminated soils. EPA can not definitively discount
this possiblity. However, the need for excavation and treatment of
the soils in these areas, as veIl the swale area, will be based on
the potential of soils to contribute to groundwater contamination.
The extent of any remediation in these areas will be consistent
with the remedial objectives for groundwater.
~
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Comments from Former Owners of the Londonderry Green Apartments
The former o~ners of the Londonderry Green Apartment Complex, no~ called
the ~oodland Village, submitted comments and recommendations on three
documents:
1) the FS; 2) the endangerment assessment; and 3) the RI.
The
major comments are summarized below.
1.
FS Comments
a.
Commen t :
The no-action management of migration alternative should
be chosen at the site of the condominimum complex pecause a
permanent drinking water supply is currently in use and no
contamination has migrated past site boundaries.
EPA Response: The potential exists for groundwater to migrate
toward residential drinking water wells. This is documented in the
Record of Decision and substantiated by water level measurements
taken by EPA both onsite and along Ross Drive (see Attachment B).
These measurements show a hydraulic gradient in the bedrock aquifer
at the site sloping toward the domestic supply wells along Ross
Drive, which are currently drawing on this aquifer.
Consistent with EPA policy, groundwater should be protected for its
highest benefit and .purpose. Superfund's implementation of the EPA
Groundwater Protection Strategy will seek rapid clean ups of all
current and potential drinking water where it is cost-effective to
do so. Moreover, the NCP requires selection of remedies that are
applicable or relevant and appropriate. The No Action alternative
for groundwater remediation does not comply with the requirements
of 40 CFR 264 Subpart F (Ground Vater Protection), which are
applicable and relevant requirements for this site.
Finally, neither EPA, the State
Londonderry has the legislative
use no~ or in the future at the
of New Hampshire, nor the To~n of
authority to restrict ground water
Tinkham site. This is a high
gro~th area and future development of land onsite has been
-------
o
~
o
.
proposed.
EPA believes that this reason, in addition to the
reasons outlined above, requires selection of a management of
migration alternative that effectively mitigates and minimizes
threats to and provides adequate protection of public health,
velfare and the environment.
b.
Comment: It is premature to consider groundvater treatment options
until the potential effectiveness of source control measures are
assessed. Taking this action in advance of any other is the most
logical alternative. It is possible that source control measures
alone could provide as effective a cleanup as any of the management
of migration options.
EPA Response: It is EPA's intention to proceed vith groundvater
treatment only after completion of source area excavation.
c.
Comment: All of the available hydrogeologic data indicates that
the primary source of chemical contamination to the bedrock aquifer
is the soil behind Tinkham's garage, not the other source areas as
set forth in the draft FS.
Removal or treatment of the contami-
nated soils behind the garag~ is recommended.
EPA Response: EPA agrees vith the assessment that the soil behind
Tinkham's garage i~ the primary source of chemical contamination to
the bedrock aquifer at this time.
Hovever, this does not preclude
the excavation and treatment of other potential source areas.
d.
Comment: The estimate of the volume of soil requiring remedial
action is queitionable due to inconsistencies in the method of
calculation.
EPA Response:
EPA believes that the estimates of the volumes of
soil requiring remedial action are appropriate. Actual excavation
of soils vill be determined in the field and vill be based on the
remedial objectives set forth in the Record of Decision.
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e.
Comment: There is concern that the scope of york for the draft FS
contained assumptions regarding methods of remedial action before
appropriate response objectives had been established.
EPA Re~ponse: EPA and its contractors have experience based on
york at several Superfund sites nationyide. Given the site data
and other information presented in the RI, it yas possible for EPA
and its contractors to prepare a preliminary listing of remedial
technologies that might b~ applicable at the Tinkham Garage site.
The listing in the scope of york yas not a full list of the
remedial technologies considered by EPA in the draft FS.
f.
Comment:
Task 5 of the draft FS scope of york does not state the
origin of the baseline risk assessment and no references are made
as to its preparation.
EPA Response: Task 5 of the scope of york for the draft FS
contains a paragraph yhich states that the response objectives and
criteria yill be based on results of the baseline risk assessment,
RI, and data gathered in the draft FS. Rather than detail the
methods for developing the criteria, the FS states that it yill
adhere to Section 300.68 of the National Contingency Plan
EPA guidance "Guidance on FS under CERCLA, June, 1985, 40
264 (RCRA)", and the requirements of any other applicable
State or local statutes.
(NCP),
CFR Part
Federal,
~
2. ~'Endangerment Assessment
a.
Comment: The public health impacts to residents of the condominium
complex are not likely to be significant based on the loy
concentrations of contaminants, their limited distributions in the
condominium complex area, and the minimal potential for exposure.
EPA Response: Sources of potential exposure to contaminants in the
condominium complex include the leachfields, soil pile, syale soil
source areas, and the Unnamed Tributary. EPA cannot definitively
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()
v
u
3.
rule out the potential for direct contact/ingestion of contaminated
soils. The Unnamed Tributary indicates lov levels of contamination
in surface vaters and sediments.
These levels are not considered
to pose a significant risk to public health, velfare and the
envi ronmen t.
RI Comments
a.
Comment: There is no data presented to support the assessment that
zero dravdovn occurred in veIl LGAW during the pump test. There is
no indication that a standpipe vas placed on the vell to measure
changes.
EPA Response: The comment is correct; a standpipe or stickup was
not used for monitoring vell LGAW. The artesian flov from well
LGAW was observed during the pump test and no apparent decrease in
discharge vas noted.
b.
Comment: Several borings were screened continuously through
multiple geologic strata. This practice may obscure the
relationship betveen units with regard to contaminant distribution.
EPA Response: In the course of drilling, EPA contractors
frequently observed (by field chemical screening) that the zone of
maximum contaminant concentration in a number of borings was
situated at the overburden/bedrock interface. The highly fractured
upper bedrock ofte~ supports considerable groundvater flov and can
be considered hydraulically connected to the overburden.
Furthermore, the overburden thickness in much of the study area is
less than ten feet, making the installation of separate overburden
veIls/piezometers inappropriate.
c.
Commen t :
The explanation for the presence of concentrations of
VOCs in veIl LGAW is inadequate. No significant concentration of
VOCs is reported in the surficial soils nearby and there is no
evidence of a mechanism for dovnvard transportation of material.
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EPA Response: The presence of leachfields vhich EPA believes vas
used for the disposal of hazardous vastes near veIl LGAV, combined
vith the relatively thin sandy overburden in this area, suggest
that dovnvard migration of contaminants cannot be ruled out.
d.
Comment: Estimated fracture locations in boring FV-15D noted
during drilling do not correspond to fracture locations identified
as a result of borehole logging.
EPA Response: Small fractures vhich could not be detected during
the air rotary drilling vere detected using geophysical logging,
particularly caliper logs.
e.
Comment: The borehole geophysical logging did not determine the
orientation of most of the fractures at the site. The vay in vhich
the contaminants migrate betveen parallel faults is not
demonstrated.
EPA Response: The USGS borehole televiever vork vas the only
borehole technique designed to provide information on fracture
orientation (at the intersection of the fracture and the borehole).
The geophysical data, combined vith other structure information
indicates a strongly preferred fracture orientation and a secondary
roughly perpendicular set of fractures.
f.
Comment:
The greater concentrations of VOCs observed in the field'
behind the garage, together vith vertical gradient patterns and the
presumed orientation of the fracture, indicate that ~he garage area
is probably the most significant source area.
EPA Response: Source areas associated vith the condominium complex
cannot be dismissed as potential sources of continuing groundvater
conta;nination.
Potential removal of these areas viII be determined
during design.
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Q
~
u
g.
Comment: The task of conducting permeability tests at each ne~
monitoring ~ell location ~as not fulfilled. Therefore, the
potential for soils in the source areas of the condominium complex
to allo~ migration of contaminants ~as not fully assessed..
~
EPA Response: The reason that in-situ permeability tests ~ere
conducted only in certain ne~ ~ells ~as that the minimal (less than-
ten foot) thickness of overburden in some locations made such
testing infeasible. It should be noted, ho~ever, that split-spoon
samples of overburden ~ere collected at all locations for visual
screening (and some laboratory testing) and that the drilling
cuttings were monitored throughout the borehole drilling.
h.
The RI fails to discuss the performance or result of the
Comment:
tracer study.
EPA Response:
After much discussion, EPA and its contractor agreed
that the proposed tracer study was not warranted at the time, since
the required information could be developed more cost-effectively
through other investigative means.
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VI.
REMAINING CONCERNS
~
This section describes community concerns that EPA and the State should be
aware of as they prepare to undertake the remedial design and remedial
action at the Tinkham Garage site.
A.
Concerns About Gardening
Throughout work at the site, several residents have been concerned about
the health and safety impacts of eating vegetables grown in the soil near
the site. ~hile EPA has answered that it is safe to grow 'vegetables as
long as muncipal water is used to water them, residents are still confused
about whether or not to grow vegetables. It is expected that this question
will be raised again.
B.
Concerns About Remedial Construction and Air Pollution
One resident expressed the concern that the remedial construction will
create nuisances in the neighborhood such as loud machinery and increased
traffic. This will likely become more of an issue as EPA moves closer to
the actual remedial construction.
Several residents have expressed the concern that some of the onsite
remedial treatments may contribute to air pollution because of the emission
of volatile organic compounds.
C.
Concerns About Residential Construction
Several residents have stated their concerns that residential construction
in the site area and on the site may stir up contaminated soils and also
affect groundwater flow.
Construction of onsite remedial measures will
contribute to this concern.
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o
~
ATTACHMENT A
COMMUNITY RELATIONS ACTIVITIES CONDUCTED AT THE
TINKHAM GARAGE SITE
Community relations activities conducted by EPA at the Tinkham Garage site
to-date include the follo~ing:
u
d
o
Prepared a community relations plan in April 1983.
~
~
o
Conducted onsite discussions ~ith seven residents in Londonderry,
NH, on November 20, 1985 to solicit community concerns regarding the
site.
o
Distributed a fact sheet explaining the RI to the community on
December 20, 1985.
o
Held a public meeting on February 5, 1986 at the Londonderry High
School to describe the results of the RI, to discuss the upcoming
FS, and to ans~er questions from the community. Approximately 60
people attended the meeting. At the meeting, EPA distributed copies
of the RI fact sheet, a fact sheet summarizing the Endangerment
Assessment, and a fact sheet describing the FS process and
activities planned for the FS.
o
Held telephone conversations during the ~eek of July 21, 1986 ~ith
three Londonderry residents active at or affected by the Tinkham
Garage site. The purpose of the telephone calls ~as to maintain
contact ~ith residents and to ascertain community concerns prior to
the FS public meeting.
o
Distributed a fact sheet on July 28, 1986 describing the draft FS
and the remedial alternatives under consideration for the Tinkham
Garage site.
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o
Held a public meeting on August 14, 1986 at the Londonderry Junior
High School to explain the FS process and proposed remedial
alternatives, and to respond to citizen's questions. Approximately
40 people attended the meeting.
o
Held a public hearing on August 26, 1986 at the Londonderry Junior
'High School to record comme~ts by any interested parties. A
transcript of this hearing is available at the Londonderry To~n Hall
and the Leach Public Library in Londonderry. Three parties read
comments in the record.
o
Held a public comment period on the proposed FS cleanup
alternatives. It lasted from August 15, 1986 to September 5, 1986.
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AT T A C H'1 E:; T B
~ '.,: l~' ~.~ [) ~.~ !:.'T L'~~
L:-~\'l- ?:,"'; '~~"~ E:< -:-:':... ~ p ~('"T t-~ C T I C) >~
P ::.'C:; I U\ I
.;~~ ~~~.~( ":"
OAT E:
July 14, 1986
TO:
Tinkham Garage Technical

navid P. Frasca ~
project Manager

David Lang (Z)~
Hydrogeologist
Data File
FROM:
THRU:
SUBJ:
Water Level Measurements - Tinkham Garage
site and Ross Drive.
On June 27, 1986 water level elevations in both, wells on site and
Ross Drive were collected and compared. The purpose of this
comparison was to determine if the potential exists for contaminated
groundwater to migrate from the Tinkham site to residential wells
in use along Ross Drive.
To date it is believed contaminated groundwater in the overburden
aquifer migrating from the garage area is discharging to the wetlands
area in the southeast portion of the site. Contaminated groundwater
in bedrock is believed to travel in a fracture zone approximately
parallel to Ross Drive. This water is believed to discharge to the
unnamed tributary in 'the western portion of the site, and to the ground
surtace from a number of freely flowing bedrock wells on site.
The question has been raised as to the possibility of contaminated
groundwater migrating perpendicular to the deep bedrock fracture
zone toward residential wells along Ross Drive, in secondary fractures
and in overburden. Based on the comparison of water level elevations
taken from the _inkham site ,and Ross Drive, and based on the
orientation of the hedrock, the potential does exist for groundwater
to migrate from Site toward residential wells along Ross Drive.
However, it should be stated that due to the uncertainties associated
with the direction of groundwater flow in fractured rock, dpfinitive
understanding of flow direction based solely on water level measurements
are not conclusive. A more detailed study, possibly utilizing tracer
compounds or sophisticated geophysical techniques would be required
to fully characterize this flow.
Technical data collected and analyzed follows.
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ATTACW!E:JT B (cont'd)
~ate~ L2v~1 ~eaSJre~2nt~
Tin~ham G3raje Site
~:)nj()njerr:l, New Hant)shire
]'-1;1'2 27, 1986
      Elevation to   Depth to  Wa ter Leve 1
 I,-J e 11 l~umbe r Time TOp of Casing  Water   Elevation
        (feet)    (feet)  (feet)
 F ~-J-l 0   950   291.09    5.16   285.93
 F 1,1-1 0 D   955   292.36    21.41   270.95
 H,J-ll   1015   282.57    2.69   279.88
 F\-J-llD   1025   282.82    10.40   272.42
 H,J-12   1115   279.33    6.83   272.50
 F~J-13   1055   279.48    5.71   273.77
 n-J-22D   1340   253.54    6.18   247.38
 *F\,J-25D      282.44       
 n'J- 2 6   1145   285.40    3.83   281.57
 F',1-28D   1040   272.32    7.84   264.48
* Unable to obtain water level elevation due to obstruction in we 11 .
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ATTACH~E~T B (cont'd)
Water Level ~easurements
Tinkham Garage Site - Ross Drive
Londonderry, New Ham?shire
J un e 2 7, 1 9.8 6
    Elevation to Depth to Water Level
Well Number Time TOp of Casing Water  Elevation
    (feet)  ( feet) (feet)
3 Ross 1558 288.41  53.13 235.28
8 Ross 1550 279.98  34.14 245.84
11 ROss 1544 249.72  19.80 229.92
16 Ross 15...2 241.92  12.48 .229.44
        ~
17 Ross 1539 235.19  2.63 232.56
32 Ross 1533 257.05  39.03 217.97
4
~.
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ATTACH~E~T B (cont'd)
1.
3 Ross Drive - Thompson
Well Type: bedrock
De p t h : 250 I
Yield: good
2 .
8 Ross Drive - Cimini
Well Type: bedrock
Dep tl1: unkn own
Yield: low
3 .
11 Ross Drive - Warnick
Well Type: bedrock
Depth: unknown
Yield: good
B-4
4 .
16 Ross Drive - Bech~rd
Well Type: bedrock
Depth: 200'
Yield: 20 gpm
5 .
17 Ross Drive
Well Type: bedrock
Depth: unknown
Yield: good
6 .
32 Ross Drive - Marquis
Well Type: bedrock
Depth: unknown
Yield: 8 gpm
.
t!
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