United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R01 -92/068
September 1992
PB93-963709
v°/EPA Superfund
Record of Decision
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NOTICE
The appendices listed in the index that are not found in this dOcument have been removed at the request of
the issuing agency. They contain material which supptement. but adds no fur1her applicable informatiOn to
the content of the document. All supptemental material is. hoWeVer. contained In the administrative record
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REPORT DOCUMENT A nON 11. REPORT NO. r~ :so Alc:lpi8nta ~ No.
PAGE EPA/ROD/ROl-92/068
4. TIaa IUId S&mtItI8 S. Report D818
SUPERFUND RECORD OF DECISION 09/29/92
Tibbetts Road, NH
II.
First Remedial Action - Final
7. AUlllOI'(a) B. Pwformlng 0rg8nID1I0n AIpL No.
9. Pertonnlng Organlzadon Nama IUId ~ 10. ProjactlTaaklWork UnIt No.
11. Contract(C) 01' Gr~G) No.
(C)
(G)
12. ~ng Organlza1lon Nama and AddreM 1:SO Typa of Aaport. PMod Co--
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. Supplementary No...
PB93-96370:9
16. Abatract (Urnlt: 200 worda)
The 2-acre Tibbetts Road site is a former waste storage and disposal facility in
Barrington, Strafford County, New Hampshire. Land use in the area is predominantly
industrial with one unoccupied residence onsite and five occupied residences located
within 200 feet of the site. The residents within one-half mile of the site used
ground water as their primary source of drinking water. From the 1940's to present,
the site was used as a storage area for industrial wastes from automobile production
and painting. In 1982, state investigations revealed that improper storage techniques
had led to many of the storage barrels discharging their contents to the ground,
resulting in contamination of the ground water. In 1984, EPA conducted a removal
action that involved removing barrels and contaminated soil from the site for offsite
treatment and disposal. A second removal action was conducted by EPA in 1986, which
included excavating 405 cubic yards of soil containing dioxins, PCBs, VOCs, and SVOCs,
backfilling and capping the area, shipping PCB- and VOC-contaminated soil offsite, and
storing dioxin-contaminated soil onsite, to be destroyed by infrared incineration at a
later date. In 1987, EPA and the state constructed a drinking water treatment plant to
(See Attached Page)
17. DocunwntAnalyaia .. Daacri""'J8
Record of Decision - Tibbetts Road, NH
First Remedial Action - E''ina 1
Contaminated Media: debris, gw
Key Contaminants: VOCs (benzene, PCE, TCE, xylenes), other organics (PAHs), metals
(chromium, lead)
b. IdendtleralCpen-Ended Terma
c. COSA TI FIeIdIGroup
18. Availability Slatement 18. SecurIty Clua (Thla Report) 21. No. of Pagaa
None 146
j 2G. SecurIty CIua (T11Ia Page) ~ PrIce
None
ISee ANSl-Z3II.18 See ,...lTUCti..... on Re- (4-17)
50272-101
(Formarty N11$.35)
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8PA/ROD/ROl-92/068
Tibbetts Road, NH
first Remedial Action
Abstract (Continued)
- Final
provide an alternate water supply to local residents. This ROD addresses a final remedy
for debris and ground water at the site. The primary contaminants of concern affecting
the debris and ground water are VOCs including benzene, PCE, TCE, and xylenes; other
organics, including PAHs; and metals, including chromium and lead.
The selected remedial action for this site includes removing and disposing buildings and
debris offsite to access the areas of contamination more efficiently; disposing of
15 barrels of incinerator ash residue and spent carbon filters from a previous removal
action offsite; using trenches or wells to intercept ground water in the bedrock aquifer;
designing and constructing a ground water dewatering and extraction system in the
overburden aquifer, and treating air emissions using granular activated carbon; treating
the contaminated,ground water in an onsite treatment plant using metals precipitation,
chemical additives, and UV/oxidation, with discharge of the treated ground water to
injection wells onsite to promote flushing of weathered bedrock; disposing of the
resulting sludge Offsite; conducting a treatability study to determine the appropriate
oxidant and concentration needed to destroy VOCs; upgrading and expanding the water
supply, as needed; monitoring ground water and surface water; modifying or abandoning
wells, if necessary; and implementing institutional controls, including deed and ground
water use restrictions to prevent the use of contaminated ground water. The estimated
present worth cost for this remedial action is $3,776,000, which includes a net present
worth O&M cost of $2,047,000 for 30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific ground water clean-up goals are based on SDWA MCLs and MCLGs and state
standards and include PCE 5 ug/l; toluene 1,000 ug/l; naphthalene 1,460 ug/l; arsenic
50 ug/l; manganese 3,650 ug/l; bis(2-ethylhexyl)phthalate 4 ug/l; benzene 5 ug/l; xylenes
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REGION I
,
RECORD OF DECISION
TIBBETTS ROAD SUPERFUND SITE
BARRINGTON, NEW HAMPSHIRE
-------
DECLARATION FOR THE RECORD OF DECISION
Tibbetts Road Superfund Site
Barrington, New Hampshire
STATEMENT OF PURPOSE
This Decision Document presents the selected remedial action for
the Tibbetts Road Superfund Site in Barrington, New Hampshire,
developed in accordance with the Comprehensive Environmental
Response, Compensation and Liability Act of 1980 (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act of
1986 (SARA), the National Oil and Hazardous Substances
Contingency Plan (NCP), and 40 CFR Part 300 et seq., as amended.
The Region I Administrator has been delegated the authority to
approve this Record of Decision.
The State of New Hampshire concurs with the selected remedy.
STATEMENT OF BASIS
This decision is based on the administrative record which has
been developed in accordance with Section 113 (k) of CERCLA and
which is available for public review at the Barrington Public
Library in Barrington, New Hampshire and at the Region I Waste
Management Division Records Center at 90 Canal Street, Boston,
Massachusetts. The Administrative Record Index (Appendix E to
the ROD) identifies the items which comprise the Administrative
Record upon which the selection of the remedial action is based.
ASSESSMENT OF THE SITE
Hazardous substances have been released, or there is a
substantial threat. of release, into the environment. Response
actions are necessary to protect public health, welfare, or the
environment. Actual or threatened releases of hazardous
substances from this Site, if not addressed by implementing the
response action selected in this ROD, may present an imminent and
substantial endangerment to .the public health or welfare or to
the environment. .
DESCRIPTION OF THE SELECTED REMEDY
The selected remedy for the Tibbetts Road Superfund Site will
utilize management of migration (or ground water control)
technologies to obtain a comprehensive remedy.
The ,management of migration. remedial measures include:
.
upgrade and improvement of the existing drinking water
distribution system;
.
capture of contaminated ground water in the overburden
-------
wells;
.
removal of inorganic (metallic) contaminants from
ground water through chemical flocculation,
sedimentation and filtration;
.
destruction of organic contaminants from ground water
through ultra-violet catalyzed oxidation (UV-
Oxidation);
.
capture of highly contaminated ground water and soil-
gas through the use of dewatering and vacuum extraction
on-site; the air stream will be treated with carbon
absorption, the ground water will be treated in the
afore-mentioned ground water treatment process; and
.
discharge of treated ground water into the overburden
and bedrock aquifers to effect containment and enhance
ground water recovery and cleanup.
DECLARATION
The selected remedy is protective of human health and the
environment, attains federal and state requirements that are
applicable or relevant and appropriate for this remedial action,
and is cost-effective. This remedy satisfies the statutory
preference for remedies that.utilize treatment as a principal
element to reduce the toxicity, mobility, or volume of hazardous
substances. In addition, this remedy utilizes permanent.
solutions and alternative treatment technologies to the maximum
extent practicable. .
-1/ J.~qv
Da e
ie Belaga
Regional Administ
u.s. EPA, Region I
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I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.
XI.
RECORD OF DECISION
TIBBETTS ROAD SUPERFUND SITE
TABLE OF CONTENTS
SITE NAME, LOCATION AND DESCRIPTION. . . . . . . . .
A. General Description. . . . . . . . . . . . .
B. Geology and Hydrogeology of the Site. . . . .
C. Alternate Drinking Water Supply . . . .
SITE HISTORY AND. ENFORCEMENT ACTIVITIES. . . . . . .
A. Land Use and Response History. . . . . . . .
B. Enforcement History . . . . . . . . . .
COMMUNITY PARTICIPATION
. .. . .
.......
. . . .
SCOPB AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION. .
SUMMARY OF SITE CHARACTERISTICS . . . . . . . .
A. Soil. . . . . . . . . . . . . . . . . . . . .
B. Structure and Surrounding Area. . . . . . . .
C. Air . . . . . . . . . . . . . . . . . . . . .
D. Surface Water and Sediments. . . . . . . . .
B. Ground Water. . . . . . . . . . . . . .
SUMMARY OF SITE RISKS
. . . .
. . . . .
. . . .
DEVELOPMENT AND SCREENING OF ALTERNATIVES. . . . . .
A. Statutory Requirements/Response Objectives. .
B. Technology and Alternative Development and
Screening. . . . . . . . . . . . . . .
DESCRIPTION OF ALTERNATIVES
. . . . . .
. . . .
SUMMARY OF TBB COMPARATIVE ANALYSIS OF ALTERNATIVES
THE SELECTED REMEDY . . . . . . . . . . . . . .
A. Interim Ground Water Cleanup Levels. . . . .
B. Description of Remedial Components. . . . . .
STATOTORY DETERMINATIONS. . . . . .. . . . . . . . . .
A. The Selected Remedy is Protective of Ruman
Health and the Environment. . . . . . . . . .
B. The Selected Remedy AttainsARARs . . . ... .
C. The Selected Remedial Action is Cost-
Bffecti ve . . . . . . . . . . . . . . . . . .
D. The Selected Remedy Utilizes Permanent
Solutions and Alternative Treatment or
ResOurCe Recovery Technologies to the Maximum
Extent Practicable. . . . . . . . . . . . . .
B. The Selected Remedy Satisfies the Preference
for Treatment Which Permanently and
Significantly reduces the Toxicity, Mobility
or Volume of the Hazardous Substances as a
Principal Element. . . . . . . . . . . . . .
1
1
1
3
3
3
6
6
7
8
8
10
10
10
12
16
23
23
24
25
33
44
45
48
58
58
59
69
70
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XII.
DOCUMENTATION OF NO SIGNIFICANT CHANGES
. . . .
XIII.
STATE ROLE. . . . .
. . . . .
. . . . . .
ENDNOTES
. . . .
. . . . . . . .
APPENDIX A
FIGURES
. . . . . .
. . . . . .
GENERAL LOCATION MAP
. . . . .
. . . . .
. . . . . . .
TOPOGRAPHY AND SURFACE WATER HYDROLOGY
. . . . .
. . . . . .
SITE FEATURES AND SURROUNDING AREA
. . . . .
. . . . . . . .
LOCATIONS OF CROSS SECTIONS. . .
. . . .
. . . .
NORTH-SOUTH CROSS SECTION THROUGH SITE
. . . .
. . . .
NORTH-SOUTH CROSS SECTION, EAST OF SITE
EAST-WEST CROSS SECTION THROUGH SITE
. . . . .
........
. . . .
PUBLIC WATER SUPPLY SYSTEM
. . . . .
.......
. . . . .
SOIL SAMPLE LOCATIONS & FORMER BARREL STORAGE LOCATIONS. . .
SURFACE WATER AND SEDIMENT SAMPLING LOCATIONS. .
. . . . . .
MONITORING WELL LOCATIONS. . . . . . .
. . . .
.......
TOTAL VOLATILE ORGANIC COMPOUNDS IN THE OVERBURDEN AQUIFER
CONTOUR MAP OF ARSENIC CONCENTRATIONS IN THE OVERBURDEN
AQUIFER. . . . . . . . . . . . . . . . . . . . . . . .
TOTAL VOLATILE ORGANIC COMPOUNDS IN THE BEDROCK AQUIFER. . .
CONCENTRATION DISTRIBUTION OF ARSENIC IN THE BEDROCK
AQUIFER. . . . . . . . . . . . . . . .
. . . . .
EXTENT OF OVERBURDEN AQUIFER CONTAMINATION
. . . .
. . . . .
EXTENT OF BEDROCK AQUIFER CONTAMINATION.
CONTAMINANT MIGRATION FROM 1985 TO 1990 .
. . . . .
. . . . .
. . . .
CONCEPTUAL SITE PLAN
.......
. . . . . .
. . . . . . .
GROUND WATER TREATMENT SYSTEM USING ULTRAVIOLET CATALYZED
OXIDATION. . . . . . . . . . . . . . . . . . . .
GROUND WATER TREATMENT SYSTEM USING AIR STRIPPING. . . . . .
72
73
74
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
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APPENDIX B
TABLES
. . . . .
. . . .
98
GROUND WATER CONTAMINANTS IN THE OVERBURDEN AND BEDROCK
AQUIFERS. . . . . . . . . . . . . . . . . .
99
CONTAMINANTS OF CONCERN IN GROUND WATER
. . . . . . .
. 101
CONTAMINANTS OF CONCERN IN SOIL.
CONTAMINANTS OF CONCERN IN SURFACE WATER
. . . . . .
. 103
. 103
.......
PRESENT CARCINOGENIC RISK FOR SOIL AND SURFACE WATER
. 104
PRESENT NON-CARCINOGENIC RISK FOR SOIL AND SURFACE WATER
. . 105
POTENTIAL FUTURE CARCINOGENIC RISK FOR SOIL, .SURFACE WATER,
AND GROUND WATER FROM OVERBURDEN AND BEDROCK AQUIFERS
. 106
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR SOIL, SURFACE
WATER, AND GROUND WATER FROM OVERBURDEN AND BEDROCK
AQUIFERS. . . . . . . . . . . . . . . . . . . . .
. . . 108
POTENTIAL FUTURE CARCINOGENIC RISK FOR GROUND WATER. . . . 110
POTENTIAL FUTURE CARCINOGENIC RI SK FOR GROUND WATER . . . . . III
POTENTIAL . FUTURE NON-CARCINOGENIC RISK FOR GROUND WATER . . . 112
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR GROUND WATER . . . 113
ECOLOGICAL CONTAMINANTS OF CONCERN
ALTERNATIVES DEVELOPED
..........
. . . . . .
. 114
. . . 115
.........
SUMMARY OF ESTIMATED PRESENT WORTH COSTS
. . . .
. . . 117
INTERIM GROUND WATER CLEANUP LEVELS.
.......
. . 118
WATER QUALITY STANDARDS AND CRITERIA
. . . . .
. . . . .
. . 120
APPENDIX C - APPLICABLE AND RELEVANT AND APPROPRIATE REQOIREMENTS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "122
APPENDIX D - RESPONSIVENESS SUMMARY
APPENDIX E - ADMINIS'l'RATIVE RECORD INDEX
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SEPTEMBER 29, 1992
I.
SITE NAME, LOCATION AND DESCRIPTION
A. General Description
The Tibbetts Road Site is in the southeastern portion of New
Hampshire, in the Town of Barrington (Strafford County),
approximately eight miles west of the City of Dover and two miles
northeast of the junction of New Hampshire Route 4 and Hall Road.
Figure 1 on page 77 shows the Site location. The Site is located
on the US Geological Survey map of the Barrington Quadrangle1 at
longitude 71°2' and latitude 43°11'.
The Site is on a topographic high, a ridge, that serves as the
drainage divide between the Oyster River and Bellamy River.
watersheds. Wetland areas exist approximately seven hundred feet
northeast and five hundred feet southwest of the Site. Surface
water drainage is not well defined at the Site and occurs
primarily as sheet flow. The nearest, permanent water body is
Swains Lake, approximately nine hundred feet to the northeast.
This lake is used for recreational purposes and as a drinking
water source. The location of the Site relative to the
watersheds and surface water bodies is shown in Figure 2 on page
78.
The Site consists of approximately two acres of land in a rural,
residential neighborhood. The Site contains an unoccupied single
family residence, approximately two hundred yards of debris
including automobile tires, and fifteen 55-gallon barrels
containing contaminated materials. The contents of these barrels
are discussed on page 10 of this document. Five occupied, single
family dwellings lie within two hundred feet of the Site.
The area of past storage and disposal of hazardous wastes (the
Site) lies within the boundaries depicted on the Town of
Barrington tax maps, lot 41 on sheet 10 and is shown as the
property labelled "Johnson".in Figure 3 on page 79. However, for
purposes of permitting, the Site also includes all adjacent are~s
underlain by ground water contaminated with hazardous wastes
exceeding the cleanup levels defined in Section X (A) below.
B. Geology and Hydrogeology of the Site
Geology at the Site consists of approximately seventy feet of
unconsolidated material, i~terpreted as glacial till and referred
to as. overburden throughout the remainder of this text.
Underlying the overburden is a weathered bedrock of varying
thickness that transitions to a competent, albeit fractured,
crystalline bedrock.
The overburden may be divided into two distinct layers. The
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 2
sandy to silty glacial till that contains minor lenses of clay
and gravel. The upper overburden is approximateiy twenty-five
feet thick in the area of the Site and the water table varies
from the ground surface during the spring and autumn months to
eight feet below the ground surface during the summer months.
The upper overburden layer varies in permeability; however, is
highly permeable in many areas. The upper overburden aquifer
contains the most contaminated ground water at the Site. Ground
water travel times in the upper overburden aquifer vary between
0.2 feet per year on the ridge crests to twenty feet per year on
the ridge flanks. Ground water flow within the upper overburden
is split by a ground water divide which crosses the Site as shown
on Figure 2 on page 78. One component of ground water flow is to
the southwest and another to the northeast.
The lower-most portion of the overburden is comprised of a dense,
nearly consolidated, silt to clay material that acts as. an
aquitard, restricting the vertical flow of ground water to the
bedrock. aquifer. This dense; silty overburden material is
limited in lateral extent, is thickest -beneath the Site (fifty-
five feet), and thins rapidly to pinch-out approximately one
hundred to two hundred feet from the Site. Throughout the
remainder of this document the saturated portion of the upper
overburden shall be referred to as the "upper overburden aquifer"
and the lower overburden shall be the "aquitard". The term
"overburden aquifer" will be used when referring to both the
upper overburden aquifer and aquitard in this document.
The bedrock aquifer, composed of a fractured and deformed quartz
monzonite, may also be divided into two units: the weathered
bedrock and the competent bedrock. Ground water flow in the
weathered bedrock aquifer and the competent bedrock aquifer is
substantial and interconnections exist between the weathered
bedrock and competent bedrock. Taken together these aquifers
form the bedrock aquifer.
The upper portion of the bedrock, the weathered bedrock aquifer,
is highly fractured and weathered. The thickness of the
fractured and weathered portion varies from apparently five to
forty feet in the area near the Site. The cause of this
variability is unknown. Permeability in this portion of the
bedrock, although restricted to fracture flow, is high (=1.2 x
10-4 centimeters per second). A core taken in the weathered
bedrock, showed vertical and horizontal fracture zones, many of
which were well oxidized and iron stained. This indicates
substantial flow within the weathered bedrock. Ground water flow
within the weathered bedrock is apparently to the northwest,
following the general slope of the underlying competent bedrock
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 3
The underlying, more competent bedrock, has fewer fractures.
However, water yields from deep, single fractures in portions of
this bedrock unit are capable of producing over one hundred
gallons per minute (gpm). Ground water flow within the competent
bedrock roughly mimics the surface water drainage divide in its
flow direction. The flow of the bedrock ground water is directed
to the west, the drainage basin of the Oyster River, on the west
side of the drainage divide; and to the northeast, and Swains
Lake and the Bellamy River, on the east side of the divide.
Figures 3, 4, 5, 6, and 7, beginning on page 79, show the
physical Site features and provide cross sections to illustrate
the underlying geology and hydrogeology of the Site.
C. ~ternate Drinking Water Supply
In 1987, in response to contamination at the Site, the
Environmental Protection Agency and the State of New Hampshire
constructed and made operational a drinking water treatment
plant. This plant uses Swains Lake as a source of water, and
supplies treated water to the majority of residences within one-
half mile of the Site. Many of the wells which served those
residences were either contaminated by the Site, or were likely
to be contaminated by the Site. The operation and maintenance of
this water supply system is currently performed by a group of
residents. These residents formed a separate pOlitical entity,
the Swains Lake Village Water District. The distribution for
this system is depicted in Figure 8 on page 84. The system
currently supplies approximately 15,000 gallons of drinking water
per day to residents surrounding the Site2.
A more complete description of the Site can be found in the
Remedial Investigation Report at pages 1-2 through 1-6.
II.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
A. Land Cse and Response History
On the basis of a complaint, the New Hampshire Division of Public
Health Services (DPHS) investigated the Site in April and May of
1982. Mr. Alexander Johnson, the Site owner at that time,
possessed at least three hundred thirty-seven 55-gallon barrels.
Initial sampling of the contents of these barrels indicated the
presence of acetone, benzene, toluene, xylenes, trichloroethylene
(TCE), and 4-methyl-2-pentanone (MIBK). Through information
supplied by the Site owner, and based on the general condition of
the waste storage areas and containers, it was apparent that
these wastes had been present at the Site for an extended period
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 4
from industrial processes, primarily automobile production and
painting, in the 1940's and 1950's. Many of the barrels had
discharged portions, or all, of their contents to the ground
surface at the time of the initial investigations.
Monitoring of residential wells in the vicinity of the Site by
the New Hampshire Water Supply and Pollution Control Commission
(NHWSPCC) began in June 1982. Analysis of residential wells
detected contamination consisting primarily of benzene, xylene,
toluene, MIBK, acetone and TCE. Residential wells directly
adjacent to the Site were affected first, and subsequently
additional wells, more distant from the Site became contaminated.
Monitoring of residential wells occurred sporadically from 1982
through 1987 when the water supply system began supplying water.
The wells of those residences that were connected to the water
supply system were cut-off below ground and had a steel cover
welded on to prevent use. .
DPHS issued a Notice of Violation and Order of Abatement letter
on August 16,-1982 to the Site owner,> Alexander Johnson. This
letter ordered that the Site owner cease transferring the barrels
to other places on the property, or the contents of the barrels
to other containers, and to characterize the contents of all the
barrels. The DPHS and NHWSPCC then proceeded to collect and
analyze additional soil and surface water samples from three on-
site areas containing barrels, hereinafter referred to as areas
A, B, and C and shown on page 85 as Figure 9. As a result of the
analysis of these samples, DPHS and NHWSPCC found Volatile
Organic Compounds (VOCs) in the soil and surface water. During
this investigation the DPHS determined on March 13, 1984 that a
fire involving the drummed waste was likely and that such a fire
would pose "an extreme life safety hazard" to members of the
Johnson household and other residents on Tibbetts Road.
On March 20, 1984 the State of New Hampshire requested that EPA
intervene to eliminate the hazard to human health posed by these
barrels and contaminated soil. After analysis of some of these
barrels, the contents were found to consist of acetone, toluene,
ethyl benzene, xylene, TCE, methyl isobutyl ketone (MIBK) and
pOlychlorinated biphenyls (PCBs). After characterizing and
consolidating the wastes, EPA transported the wastes to SCA
Recycling Industries of Braintree, Massachusetts for treatment
and disposal3. .
In further response to the March 20, 1984 request by the State of
New Hampshire, EPA performed follow-up studies which identified
areas of soil contamination and indicated that no buried barrels
of wastes exist. These investigations led to the excavation of
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 5
VOCs, and semi-volatile organic compounds (SVOCs), from the
former barrel storage areas Band C, in March and April 19864.
After the excavation of the contaminated soil, these areas were
brought back to grade with clean fill and then capped with a
six~y-mil-thick high density polyethylene liner which remains in
place. EPA transported and disposed of PCB-contaminated and VOC-
contaminated soil at a Treatment, Storage, and Disposal facility
in Fort Wayne, Indiana. The dioxin contaminated soil was stored
on-site in a dumpster that was welded shut. EPA funded and
supervised the on-site destruction of dioxin-contaminated soil by
means of an infrared incinerator in November 19865. The
incinerator ash remains on-site in twelve barrels.
The March 20, 1984 request by the State of New Hampshire for EPA
assistance also identified a potential drinking water risk. The
U.S. Department of Health and Human Services recommended
continued monitoring of drinking water wells near the Site, and
that plans for both an interim and a permanent water supply be
developed6. The State of New Hampshire conducted a study
Hydrogeological Site Study - Commission Report #1447 to
characterize the source and migration of Site contaminants. A
second study conducted by the EPA, Geohydrological
Investigations8, identified an area in which ground water was,
or would potentially become, contaminated by Site contaminants."
Due to extensive ground water contamination identified by these
reports, it became necessary to supply the residents living in
this area with an alternate water supply9. The water supply
system was installed during the summer of 1987. The
characteristics of this supply system are discussed generally on
page 3 of this document.
To determine the nature of potential exposure to Site
contaminants for the risk assessment, it was necessary to
determine the current and future land use of the area. The area
immediately surrounding the Site is residential and will remain
so. Also, additional residential units are being constructed and
are planned for the area within one-half mile of the Site. The
new residences will connect to the water distribution system and
will not have wells.
A more detailed description of the Site history can be found in
the Remedial Investigation Report at pages 1-7 through 1-9 and in
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 6
B. Enforcement History
On February 13, 1986 EPA notified one party, the Ford Motor
Company, who either generated wastes that were shipped to the
facility, arranged for the disposal of wastes at the facility, or
transported wastes to the facility of their potential liability
with respect to the Site. Negotiations commenced with this
potentially responsible party (PRP) regarding the settlement of
the PRP's liability at the Site. These negotiations resulted in
the development of a scope of work for a Remedial Investigation
and Feasibility Study (RIfFS) which was submitted in October
1987. On February 22, 1989, "counsel for the PRP stated that the
PRP was not willing to perform an RIfFS. Due to the PRP's
unwillingness to negotiate performance of an RIfFS, on June 12,
1989, EPA notified the PRP that it was not sending the PRP a
Special Notice letter.
The PRPs has not been active in the remedy selection process for
this Site. " -Technical comments presented by the PRP during the
public comment period at a meeting were summarized in writing,
and the summary and written comments were included in the
Administrative Record.
The Department of Justice filed a Civil Action against the PRP,
Ford Motor Company, seeking past costs, including the cost of a
removal action at the Site from 1984 to 1987, and a declaratory
judgement regarding Ford's liability for expenses that EPA may
incur in the future, in the U.S. District Court, District of New
Hampshire on March 28, 19911°. That action is pending.
III.
COMMUNITY PARTICIPATION
Throughout the Site's history, community concern and involvement
has varied. Initially, community concern was yery high and some
residents testified in Congress. However, once a clean supply of
drinking water was supplied and the direct threats to human
health and the environment were removed, overall community
interest became medium in the area surrounding the Site and low
throughout the remainder of the community. The majority of the
concerned residents directly abut the Site. EPA has kept the
community and other interested parties apprised of the Site"
activities through informational meetings, fact sheets, press
releases and public meetings.
During April 1990 EPA released a community relations plan
outlined a program to address community concerns and keep
citizens informed about and involved in activities during
remedial activities. On June 19, 1992 EPA made the
administrative record available for public review at EPA's
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PAGE 7
offices in Boston and at the Barrington Public Library in
Barrington, New Hampshire. EPA published a notice and brief
analysis of the Proposed Plan in the Foster's Daily Democrat on
June 15, 1992 and made the plan available to the public at the
Barrington Public Library in Barrington, New Hampshire.
On June 24, 1992 EPA held an informational meeting to discuss the
results of the Remedial Investigation and the cleanup
alternatives presented in the Feasibility Study and to present
the Agency's Proposed Plan. Also during this meeting, the Agency
answered questions from the public. From June 25 to July 24,
1992 the Agency held a thirty day public comment period to accept
public comment on the alternatives presented in the Feasibility
Study and the Proposed Plan and on any other documents previously
released to the public. On July 14, 1992 the Agency held a
public meeting to discuss the Proposed Plan and to accept any
oral comments. A transcript of this meeting and the comments and
the Agency's response to comments are included in the attached
responsiveness summary. .
IV.
SCOPE AND ROLE or OPERABLE UNIT OR RESPONSE ACTION
A prior removal action, described beginning on page 3 of this
document and on pages 1-7 through 1-9 of the Remedial
Investigation, eliminated the source areas of contamination and
the immediate threat to human health and the environment. The
remedy selected in this Record of Decision, was developed to
address the future threat to human health and the environment
posed by contaminated .ground water. The prior removal action,
combined with this management of migration remedy, will
constitute a comprehensive approach for Site remediation.
In summary, the remedy provides for the recovery and treatment of
contaminated ground water, and the disposal of treated water.
Contaminated ground water will be recovered through trenches and
wells. Highly contaminated ground water will be recovered
through vacuum extraction of a limited area on-site. Recovered
ground water will be treated to remove and destroy contaminants
on-site prior to disposal of the treated water. Treated water
will be injected into the overburden or bedrock aquifer on-site.
The remedy will also include the improvement and possible
extension of the water supply system; the removal of the house
on-site; and the removal of treatment residuals, the fifteen
barrels described on page 10 of this document. The actions
outlined above will eliminate the future hazard posed by the
ingestion of drinking contaminated ground water.
Th{s remedial action will address the principal threat to human
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PAGE 8
the potential ingestion of ground water contaminated from the
Site. This remedial action will recover and treat contaminated
ground water, and will supply an alternate source of drinking
water.
v.
SUMMARY OF SITE CHARACTERISTICS
Chapter 1 of the Feasibility Study (FS) contains an overview of
the Remedial Investigation (RI). The significant findings of the
Remedial Investigation are summarized below.
A. Soil
Soil, both on-site and off-site, was the focus of previous
investigations conducted by the EPA and NHDES12. Prior to the
RI, 405 cubic yards of VOC and PCB contaminated soil were
excavated and transported off-site. Also 3.5 yards of dioxin an~
PCB contaminated soil were excavated, stored on-site, and
ultimately treated in an infrared incinerator. The residue from
this incineration process remains in twelve 55-gallon barrels at
the rear of the on-site unoccupied residence. Therefore, the
purpose of the soil investigation in the RI was to assess the
effectiveness of the previous soil excavation, determine the
impact of attenuative mechanisms on the contaminants, and.
corroborate the results of the previous investigations.
During the RI field investigations, from October 1990 to January
1991, ground water elevations fluctuated up to eight feet with
the seasonal high water table on-site being within one foot of
the ground surface. This oscillation of the water table is an
important means of contaminant transport and distribution in
ground water and soil, because it continually brings highly
contaminated groundwater into contact with uncontaminated soil.
This causes some of the contaminants, generally VOCs or SVOCs, to
sorb to the soil particles. The contaminants in these soil
particles are then either removed from the soil or reduced in
concentration by natural attenuation processes.
VOCs detected in the soil included TCE and toluene in extremely
low concentrations, the maximum concentrations being eleven and
two parts per billion, respectively. Two isolated locations of
moderate concentrations of tetrachloroethylene (PCE) (55 ppb and
650 ppb) exist in the vicinity of former drum storage area C.
The distribution of sampling points is depicted in Figure 9 on
page 85. Former drum storage area C is also shown in Figure 3 on
page 79.
PCE has a high vapor pressure and is expected to volatilize to
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PAGE 9
Therefore, the continued presence of PCE and low levels of other
VOCs in soil at the Site indicates that soil contamination is
perhaps the result of the fluctuating water table.
Low concentrations of SVOCs, di-n-butylphthalate, bis(2-
ethylhexyl) phthalate, benzo(a)pyrene, benzo(b)fluoranthene,
bis(2-ethylhexyl)phthalate, and di-n-butylphthalate, were
detected on-site. However, all concentrations are estimates
because they. are below the quantifiable detection limits for
those compounds. SVOCs have low vapor pressures and therefore
will not readily volatilize to the atmosphere. Benzo(a)pyrene
and benzo(b)fluoranthene have low water solubility and therefore
will not migrate readily in ground water.
One sample, located adjacent to former barrel storage area B,
contained PCBs at a very low concentration (760 ppb). PCBs are
neither volatile nor soluble in water. These properties limit
the migration of PCBs to entrainment of colloidal particles
through either wind erosion or surface water erosion.
The SVOCs, VOCs and PCBs in the soils will continue to diminish
in concentration through photochemical degradation, reaction with
free radicals and other contaminants, hydrolysis, and uptake and
metabolism by biota. VOCs exposed to the atmosphere will further
diminish in concentration through volatilization. Contrasting
the overall concentrations for VOCs, SVOCs, and PCBs for 1985
against 1990 shows a prominent overall reduction in
concentrations. Much of this reduction is accounted for by the
excavation qf the contaminated soil in former drum storage areas
Band C. However, attenuative mechanisms remain active and will
further reduce contaminant concentrations.
Lead, chromium, and vanadium were detected on-site above the
background levels obtained at one sampling point off-site.
However, a comparison of the metal ion concentrations at the Site
with ranges for concentrations in natural soil demonstrates that
the metal ions within the soil are within background values
$upplied in Table 4-14 of the RI and are what may be expected in
a natural soi113.
The Site is well vegetated, and although it is a topographic
high, the areas of soil contamination are shielded from wind
erosion by nearby structures on the southwest, and by mature
woodlands that surround the Site. Therefore, the migration of
Site contaminants adsorbed to soil is unlikely. Surface water
erosion is also not expected to be a factor in contaminant migra-
tion, as no well-defined channels exist on-site, and drainage is
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B. Structure and Surrounding Area
The abandoned residence contains personal items and shows little
evidence of waste storage or disposal activities. Surrounding
the residence is approximately two hundred yards of wood debris
and other solid wastes, including automobile tires. A small
quantity, less than twenty gallons, of paint, automotive products
(principally brake fluid) and asphalt for roofing and driveways
exists in the debris on the southeast side of the abandoned
. residence. A rusted, empty, one thousand gallon above-ground
tank rests to the northeast of the abandoned residence.
Three sealed fifty-five gallon steel barrels, which served as
granulated carbon point-of-use drinking water filters remain next
to the abandoned residence at the Site. These carbon filters
contain high concentrations of VOCs that were captured from
ground water. The carbon filters have been stored in the open,
against the on-site dwelling, since 1986.
Twelve sealed 55-gallon steel barrels, containing ash residue,
remain on the northeast side of the abandoned residence and are
covered with a tarp. The ash in these barrels is the residue
from the 1986 incineration of on-site soils contaminated with
dioxin and polychlorinated biphenyls (PCBs). The twelve barrels
of incinerator ash residue have remained on-site since 1987.
Testing of this ash revealed low levels of PCBs, less than 31.0
parts per billion (ppb), and no detectable concentrations of any
isomer of dioxin14.
c. Air
Due to the relatively low concentrations of volatile contaminants
in soil and surface water, significant concentrations of
contaminants in air due to volatilization are not expected, nor
were they observed by air monitoring. During all field
activities for the RI, air monitoring exhibited fewer than five
parts per million (ppm) total organic vapors above background.
Therefore, since no source areas are exposed at the surface, and
since qualitative sampling detected no contaminants above back-
ground, it has been concluded that there are no significant air
quality impacts resulting from VOCs on the Tibbetts Road Site.
D. Surface Water and Sediments
Surface water and sediment samples collected from Swains Lake in
1991 showed no detectable levels of contaminants from the Site.
Sampling points in an unnamed brook located five hundred feet
southwest of the Site and in a small, on-site puddle contained
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majority of the contamination at that time was toluene (110 ppb)
with low concentrations of other VOCs. The brook and the puddle
are the result of ground water discharge and infiltration
respectively; therefore, water is present at the surface only
when the water table'is high. No detection of VOCs occurred
during the analysis of samples from the Bellamy River or the
other wetlands surrounding the Site. Figure 10 on page 86 of
this document depicts the locations of the surface water and
sediment sampling points relative to the Site.
Swains Lake is the surface water body of primary concern, due to
its proximity to the Site and the fact that it is used as a
drinking water supply to residents in the area. Surface water
and sediment samples from this lake in 1991, at a point closest
to the Site (the southern end of the lake), at the Swains Lake
Village Water District treatment plant, and in the Bellamy River
revealed no detectable contamination. Moreover, the ground water
samples from monitoring wells closest to the lake have not shown
the presence of Site contaminants, indicating no quantifiable
impact on the water quality of the lake from contaminants
originating at the Site.
The intermittent broo~ southwest of the Site, which was found to
contain contaminants on one of two sampling rounds, is not within
the Swains Lake watershed and is not considered to be a source of
contamination to Swains Lake. It is however, within the Oyster
River watershed, and it drains to the south to join the Oyster
River approximately 1.5 miles from the Site. However, in EPA's
judgement, distance and an intervening wetland would attenuate
the concentrations' of anyon-site contaminants that may migrate
via this stream, prior to arriving at the Oyster River. The
concentrations of the VOCs would be reduced or eliminated by
volatilization, microbial ingestion, photo-degradation, and
hydrolysis.
Tributaries of both the Oyster and Bellamy Rivers, both class A
drinking water bodies, drain the area surrounding the Site. The
tributaries for both rivers are also class A water bodies,
suitable for fishing, swimming and drinking water use. The
Bellamy and. Oyster Rivers are sources of drinking water for
mun~cipalities downgradient from the Site. Sediment/soil
transport from the Site to the lake and rivers is not viewed as a
significant pathway, because surficial soil contamination is not
significant and the Site is a relatively flat topographic high
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B. Ground Water
Ground water contamination at the Site exists in both the
overburden and bedrock aquifers. The overburden aquifer is the
most heavily contaminated of the two. Mass balance calculations
performed in Appendix G of the RI found that approximately 570
pounds of VOCs currently exist in the overburden aquifer,- while
only a little more than two pounds of VOCs exist in the weathered
bedrock and competent bedrock together. Although the highest
total concentrations of VOCs appears to be in the weathered
bedrock, especially well 69R, the highest consistant
concentrations remain in the overburden aquifer in the general
area of the original sources, barrel storage areas Band C.
Also, the highest concentrations of TCE (7,800 ppb) and arsenic
(185 ppb) are in the overburden aquifer, while the competent
bedrock aquifer has maximum concentrations of TCE and arsenic of
110 ppb and 18 ppb respectively. .
The Site is an area of ground water recharge. Generally, that
portion of precipitation that does not runoff, infiltrates
through the soil to the overburden aquifer and ultimately to the
bedrock. However, the flow of ground water from the overburden
to the bedrock is restricted in the area of the Site due to an
aquitard contained within the overburden materials. This
aquitard induces ground water and the contaminants to flow
laterally away from the Site until this aquitard pinches out.
A general discussion of the geology and hydrogeology at the Site
is in this document beginning on page 1 as well as in more detail
in Sections 1 and 3 of the RI. An illustration of the permeable
upper overburden, the underlying aquitard, the bedrock, and other
facets of the underlying geology of the Site, is in Figures 5 and
7 on pages 81 and 83 respectively of this document. The
monitoring well network for the Site and study area consists of a
number of bedrock and overburden monitoring wells that vary in
depth from fifteen feet to over three hundred feet. Figure 11 on
page 87 depicts the monitoring well network.
Contaminant migration in the overburden aquifer mirrors the flow
of ground water from the Site. Those contaminants released from
the drum storage areas, shown in Figure 9 on page 85, entered the
upper-most overburden aquifer and migrated horizontally either to
the west or to the northeast, depending upon which side of the
drainage divide the release from the drums occurred. The
horizontal- migration is primarily a function of the lower-most
portion of the overburden acting as an aquitard, severely
re~tricting vertical flow. Horizontal flow continues to the west
and northeast until the underlying aquitard pinches out. With no
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PAGE 13
develops, thereby introducing contaminants to the weathered
bedrock. This aquitard accounts for the low concentrations of
contaminants in bedrock wells on-site and the heavy contamination
of weathered bedrock wells northeast of the Site.
Soil samples from five, ten, and fifteen feet below the ground
surface showed very low levels of absorption of contaminants by
the aquifer matrix. However, considering the heterogeneity of
the overburden aquifer, the perched conditions generated by the
aquitard, and a comparison of solubilities of many of the
contaminants with their concentrations in ground water EPA has
concluded that a potential for non-aqueous phase liquids (NAPLs)
exists in the overburden aquifer at the Site.' Non-aqueous phase
liquids 'are liquids that primarily consist of the contaminant.
The presence of light non-aqueous phase liquids (LNAPLs), which
float on top of the water table, is possible at the Site. It is
believed that LNAPLs, such as toluene and xylene, may exist in
isolated areas of the uppermost aquifer at the Site. It appears
less likely tpat dense non-aqu~ous phase liquids (DNAPLs), 'which
sink in water, exist at the Site. These DNAPLs, such as TCE,
would sink until encountering a physical/chemical barrier.
Therefore it is expected that if DNAPLs existed at the Site they
would be located in isolated pockets along the upper overburden
aquifer / aquitard interface.
The bedrock aquifer, similar to the overburden aquifer, may be
divided into two units. The upper portion of the bedrock aquifer
is highly fractured and weathered. Permeability in. this portion
of the bedrock is very high. The fracture orientation near the
bedrock/overburden interface is approximately horizontal and
cross-cut with many high angle fractures. The underlying, more
competent bedrock, has a small number of fractures of varying
orientations. However, water yields from single fractures in
portions of the competent portion of the bedrock are capable of
producing over one hundred gallons per minute (gpm).
The weathered portion of the bedrock aquifer has high
permeability. Ground water flow within the weathered bedrock has
an overall flow to the northwest. However, the direction of
local flow in the area where contaminated ground water is
migrating from the overburden into the weathered bedrock, and
subsequently the competent bedrock is to the north and northeast.
Throughout the competent portion of the bedrock aquifer, of which
only the upper two hundred feet were investigated, at least two
fracture flow systems were found to exist within the competent
portion of the bedrock aquifer. These fracture systems are not
hydraulically connected and the distribution of contaminants
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PAGE 14
ground water flow in the competent portion of the bedrock aquifer
mirrors the surface water drainage divide. The flow of the
bedrock ground water is directed to the west, the drainage basin
of the Oyster River, on the west side of the drainage divide; and
to the northeast, and Swains Lake and the Bellamy River, on the
east side of the divide.
The primary contaminants detected in the overburden and bedrock
aquifers are the VOCs: benzene, 1,2 dichloroethylene (1,2 DCE),
ethylbenzene, 4-methyl-2-pentanone (MIBK), tetrachloroethylene
(PCE), toluene, trichloroethylene (TCE), and xylene; SVOCs:
bis(2-ethylhexyl)phthalate and naphthalene; and metal species:
arsenic, chromium, lead, manganese, nickel, and vanadium. The
frequency of detection and range of concentrations of these
contaminants in monitoring wells at, and s~rrounding the Site,
are shown in Table 1 on page 99.
In the time period between 1985 and 1990 the contaminant plume in
the overburden aquifer has migrated at the rate of approximately
ten to twenty feet per year. Figure 12 on page 88 demonstrates
the widespread VOC contamination of the overburden aquifer. The
highest concentrations remain on-site, in the vicinity of the
source areas (barrel storage areas A, B, and C as shown on Figure
9). However, high concentrations of VOCs have migrated in the
overburden to the northeast and west of the Site. Arsenic
appears to have migrated from the Site as high concentrations
exist to the northeast and west of the Site, as shown in Figure
13 on page 89.
Contaminant "distribution in the bedrock aquifer is the result of
migration into the weathered bedrock and subsequently the
competent bedrock from the overburden aquifer where the aquitard
pinches out. This area appears to be in t~e area of the
weathered bedrock monitoring wells 69R and 75R shown in Figure 14
on page 90. Arsenic is in high concentrations in only two of the
bedrock wells, both of which are weathered bedrock monitoring
wells located beneath the highest concentrations of overburden
arsenic concentration as shown in Figure 15 on page 91.
Figures 16 and 17 on pages 92 and 93 of this document depict the
current extent of contamination in the overburden and bedrock
aquifers.
Two separate areas of migration of contaminants beyond the
property boundary in the overburden aquifer exists. One plume is
migrating to the northeast and another is migrating to the west.
An examination of the change of concentration between sampling
rounds in 1985 and 1990 show that the migration to the west has
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the migration of contaminants has been in the overburden aquifer
with some component of migration into the bedrock aquifer.
Figure 18 on page 94 displays the change in concentrations in
those wells in which the concentration rose during 1985 through
1990 in overburden and weathered bedrock wells.
To the northeast of the Site all of the wells, both weathered
bedrock and overburden, experienced a large increase in
contaminant concentrations for a number of individual compounds.
These compounds include TCE, benzene, PCE, 1,2 DCE, ethylbenzene,
toluene, xylene, and MIBK. To the west of the Site contaminated
ground water is migrating westward in the upper overburden
aquifer. The individual contaminants increasing in concentration
in this area include benzene, toluene, ethy1benzene, MIBK, and
xylene. On-site the only contaminant that is increasing in .
concentration in a large number of wells is 1,2 DCE which is a
degradation product of TCE.
Within the competent bedrock the primary contaminants are TCE and
benzene. Examining those wells that monitor the competent
bedrock exclusively, it is apparent that the source .area for
contamination to the competent bedrock aquifer is the continued
vertical migration of contaminants from the overburden and
weathered bedrock aquifers in the area of weathered bedrock well
69R. Figure 14 on page 90 includes wells that monitor the
weathered bedrock and competent bedrock and shows the source
area. Figure 18 on page 94 demonstrates that of the competent
bedrock monitoring wells only well 35R, which is adjacent to the
source area, is increasing in concentration. All other competent
bedrock wells are declining in concentration due to natural
attenuation mechanisms.
Monitoring of metals in ground water initiated in 1990, therefore
an assessment of metal migration is qualitative. Examining
Figures 13 and 15 on pages 89 and 91 it appears that arsenic
migration is similar to VOC migration. Two plumes exist, one
which is migrating in the overburden aquifer to the west, and
another which is migrating in the overburden aquifer to the
northeast and vertically into the bedrock in an area to the
. northeast of the Site.
Natural. attenuation of contaminants is occurring in the on-site
overburden aquifer. The natural attenuation mechanisms are
. primarily dispersion and adjection which occur as the contaminant
plume migrates from the Site. It is also possible that
biodegradation in ground water is also reducing concentrations of
. some of the VOCs. However, biodegradation, if it is occurring at
all, will not reduce all of the Site contaminants in the ground
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Natural attenuation of contaminants in the bedrock aquifer is
also through dispersion and adjection. The high rates of flow in
ground water in the competent portion of the bedrock aquifer act
to reduce contaminant concentrations. The concentrations of TCE
and benzene have fallen at least by half over the period of 1985
to 1991. The majority of bedrock wells that monitor the
competent bedrock are either below detection for all VOCs or have
extremely low levels. In 1985 eight wells adjacent to the Site
that monitor the competent bedrock were contaminated. In 1991
six of those wells remained contaminated; the other two wells are
below detection limits for all VOCs. The six contaminated
competent bedrock wells had average concentrations 187 ppb of TCE
and 45 ppb of benzene in 1985. In 1991 these average "
concentrations fell to 40 ppb and 22 ppb for TCE and benzene
respectively. Of the six contaminanted competent bedrock wells
only one well, 35R which is in the area in which contaminated
ground water is migrating into the bedrock, showed an increase in
contaminant concentrations. Natural attenuation in the bedrock
aquifer is occuring; however, will not likely reduce contaminant
levels in the bedrock aquifer. As contaminants migrate from the
highly contaminated overburden and weathered bedrock aquifers,
the concentrations of contaminants in the competent bedrock will
likely remain at the current levels or increase, with some
fluctuations, rather than further attenuate.
Hydrogeological data are more thoroughly discussed in Section 3
of the RI, and further details of the fate and migration of
contaminants are contained in Sections 4 and 5 of the RI. A list
of the contaminants of concern and the risks posed by ground
water to human health and the environment are detailed in Section
6 of the RI.
A complete discussion of Site .characteristics summarized above
can be found in the Remedial Investigation Report.
VI.
SUMMARY or SI'1'I RISKS
A Risk Assessment (RA) was performed to estimate the probability
and magnitude of potential adverse human health and environmental
effects from exposure to contaminants associated with the Site.
The.public health risk assessment followed a four step process:
1) contaminant identification, which identified those hazardous
substances which, given the" specifics of the site were of
significant concern; 2) exposure assessment, which identified
actual or potential exposure pathways, characterized the
potentially exposed populations, and determined the extent of
possible exposure; 3) toxicity assessment, which considered the
types and magnitude of adverse health effects associated with
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PAGE 17
which integrated the three earlier steps to summarize the
potential and actual risks posed by hazardous substances at the
site, including carcinogenic and non-carcinogenic risks. The
results of the human health risk assessment for the Tibbetts Road
Site are discussed below followed by the conclusions of the
ecological risk assessment.
Twenty-four contaminants of concern, listed in Tables 2, 3, 4,
found on pages 101, 103 of this Record of Decision were selected
for evaluation in the risk assessment. These contaminants
constitute a representative subset of the more than thirty-nine
contaminants identified at the Site during the Remedial
Investigation. The twenty-four contaminants of concern were
selected to represent potential site related hazards based on
toxicity, concentration, frequency of detection, and mObility and
persistence in the environment. A summary of the health effects
of each of the contaminants of concern can be found in Appendix I
of the Remedial Investigation report. .
Potential human ftealth effects associated with exposure to the
contaminants of concern were estimated quantitatively through the
development of several hypothetical exposure pathways. These
pathways were developed to reflect the potential for exposure to
hazardous substances based on the present uses, potential future
uses, and location of the Site.
Currently, the immediate area surrounding the Site is rural
residential. Five occupied residences are within two hundred
feet of the Site. In the future the immediate area will likely
become less rural and more residential. A residential
subdivision, consisting of as many as fourteen houses, has been
proposed for an area approximately three hundred feet northeast
of the Site1S. Additional residential and commercial building
activity is occurring east, west, and south of the Site. The
Site is a former residential house lot currently unoccupied and
isolated from the residential neighborhood by a ten foot high,
barbed wire topped, chain link fence.
. The following is a brief summary of the exposure pathways
evaluated. A more thorough description can be found in the
Remedial Investigation on pages 6-15 through 6-25.
Under current conditions the exposure pathways of soil and
- surface water ingestion, and dermal contact with soil and surface
water were deemed to be credible routes of exposure to Site
contaminants. Because of the installation of the alternate water
supply, ingestion of contaminated ground water is not considered
to .pose a risk presently. Future conditions will consider dermal
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PAGE 18
will also consider ingestion of contaminated ground water.
The Risk Assessment evaluated the current risk for older children
and adults ingesting 100 milligrams per day (mg/day) of
contaminated soil for 132 days per year for 24-year exposure
duration. The evaluation of current risk for de.rmal contact with
contaminated soil used the same duration of exposure and a
contact quantity of 500 mg/day of contaminated soil over a period
of 132 days per year. Under future conditions risk calculations
considered young children, as well as older children and adults
ingesting contaminated soil and dermal contact with contaminated
soil. The exposure frequency under future con~:tions increased
to 350 days/year, the exposure dose for older.~~ildren and adults
remained at current levels, and the selected exposure dose for.
young children is 200 mg/day for a six-year exposure duration.
The exposure to surface water contaminants would occur primarily
while wading in the intermittent stream, and includes incidental
ingestion of surface water and dermal contact with surface water.
The current and future risk for the ingestion of contaminated
surface water considered an ingestion rate of 25 ml/hour for one
hour per day over a period of 96 days per year. The current and
future risk for dermal contact with contaminated surface water
considered a body surface area of 1,813 square centimeters for
young children, and 4,500 square centimeters for older children
and adults; skin permeability constants appropriate for each
contaminant; and an exposure of 96 days per year. The surface
water exposure, ingestion and dermal exposure pathway also uses a
six-year exposure period for young children and a 24-year
exposure period for older children and adults.
Under potential future conditions for exposure to contaminated
ground water, the exposure factor for the calculation of
residential ingestion of ground water is 1.2 x 10-2 for
carcinogens and 2.7 x 10-2 for non-carcinogens. This is based on
an equation that considers two liters of water ingested per day
multiplied by 350/365 days per year~ multiplied by thirty years,
.and divided by seventy years for carcinogens and thirty years for
non-carcinogens using a seventy kilogram body weight.
For each pathway evaluated, an average and a reasonable maximum
exposure estimate was generated corresponding to exposure to the
. average and the maximum concentration detected in that particular
medium.
Excess lifetime cancer risks were determined for each exposure
pathway by multiplying the exposure level with the chemical
specific cancer potency factor. Cancer potency factors have been
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
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PAGE 19
reflect a conservative "upper bound" of the risk posed by
potentially carcinogenic compounds. That is, the true risk is
very unlikely to be greater than the risk predicted. The
resulting risk estimates are expressed in scientific notation as
a probability (e.g. 1 x 10-6 for 1/1,000,000) and indicate (using
this example), that an individual is not likely to have greater
than a one in a million chance of developing cancer over 70 years
as a result of site-related exposure as defined to the compound
at the stated concentration. Current EPA practice considers
carcinogenic risks to be additive when assessing exposure to a
mixture of hazardous substances.
The hazard quotient was also calculated for each pathway as EPA's
measure of the potential for non-carcinogenic health effects.
The hazard quotient is calculated by dividing the exposure level
by the reference dose (RfD) or other suitable benchmark for non-
carcinogenic health effects. Re.ference doses have been developed
by EPA to protect sensitive individuals over the course of a
lifetime and they reflect a daily exposure level that is likely
to be without an appreciable risk of an adverse health effect.
RfDs are derived from epidemiological or animal studies and
incorporate uncertainty factors to help ensure that adverse
health effects will not occur. The hazard quotient is often
expressed as a single value (e.g. 0.3 or 3 x 10-1) indicating the
ratio of the stated exposure as defined to the reference dose
value (in this example, the exposure as characterized is
approximately one third of an acceptable exposure level for the
given compound). The hazard quotient is only considered additive
fo'r compounds that have the same or similar toxic endpoints (for
exa~ple: th~ hazard quotient for a compound known to produce
liver damage should not be added to a second whose toxic endpoint
is kidney damage) .
Table 5 on page 104 depicts the carcinogenic risk summary for the
contaminants of concern in soil and surface water evaluated to
reflect present exposure by ingestion and dermal contact,
corresponding to the average and the reasonable maximum exposure
scenarios. This Table summarizes the results of the risk
Galculations and Tables 6-13 and 6-14 in the Remedial
Investigation Report.
-,
Table 6 on page 105 depicts the non-carcinogenic risk summary for
the contaminants of concern in soil and surface water evaluated
to reflect present exposure by ingestion and dermal contact,
corresponding to the average and the reasonable maximum exposure
scenarios. This Table summarizes the results of the risk
calculations and Tables 6-15 and 6-16 in the Remedial
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Table 7 on page 106 depicts the carcinogenic risk summary for the
contaminants of concern in soil, surface water, and ground water
evaluated to reflect potential future exposure by ingestion and
dermal contact, corresponding to the average and the reasonable
maximum exposure scenarios. This Table summarizes the results of
the risk calculations and Tables 6-17 and 6-18 in the Remedial
Investigation Report.
Table 8 on page 108 depicts the non-carcinogenic risk summary for
the. contaminants of concern in soil and surface water evaluated
to reflect potential future exposure by ingestion and dermal
contact, corresponding to the average and the reasonable maximum
exposure scenarios. This Table summarizes the results of the
risk calculations and Tables 6-19 and 6-20 in the Remedial
Investigation Report.
Risk calculations for ground water are divided into shallow wells
which draw on the overburden aquifer and bedrock wells. This
division is necessary since a mix of these wells were formerly
used for domestic purposes in the area surrounding the Site. The
future use, and ingestion, of contaminated ground water from the
overburden and bedrock aquifers is the basis of the risk
calculations. Detailed risk summaries are provided in a number
of Tables within this document. Tables 9, 10 on pages 110, 111
depict the carcinogenic risk for the contaminants of concern in
ground water corresponding to the average and the reasonable
maximum exposure scenarios respectively. Tables 11, 12 on pages
112, 113 depict the non-carcinogenic risk for the contaminants of
concern in ground water corresponding to the average and the
reasonable maximum exposure scenarios respectively. The results
of these Tables are in the summaries provided in Tables 7 and 8.
Summarv of Current Risks
The total current potential carcinogenic risk, using average
concentrations and a thirty year exposure duration, is 7.38xlO-7.
This level is not considered to pose a significant risk. .The
pathway with the highest carcinogenic risk is incidental
ingestion of soil, as calculated for older children and adults
(5.04 x 10~).
The total current carcinogenic risk using maximum concentrations
and a thirty year exposure period is 1.11 x 10-6, which is within
the acceptable risk range for Superfund sites. However, each
individual pathway risk is 10-7 or less. The pathway with the
highest carcinogenic risk is incidental ingestion of soil (7.07 x
10-7), as calculated for residents ages seven to thirty who may
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PAGE 21
Hazard indices for individual pathway risks under current site-
use conditions for both average and maximum concentrations for
all age groups, are less than one, indicating that
noncarcinogenic effects related to current exposures from the
Site are unlikely to occur.
Summary of Future Risks
The risks related to ingestion of ground water are calculated
separately for deep wells and for shallow wells. Using average
concentrations, the total future, potential carcinogenic risk,
for a thirty year exposure period, is 1.17 x 10-3 using shallow
well data, and 7.60 X 10-4 using deep well data. For the
exposure route of ingestion of ground water, the Site contaminant
arsenic provides the largest proportion of the potential
carcinogenic risk using average concentrations.
Using maximum concentrations, the future, potential carcinogenic
risks, for a thirty year exposure period, are 6.66 x 10-3 using
shallow well data, and 2.52 x 10-3 using deep well data~ For
maximum concentrations in ground water, the carcinogenic risks
are driven by benzene, tetrachloroethylene, trichloroethylene,
and arsenic.
The future carcinogenic risks related to incidental ingestion of
soil and dermal contact with soil are on the order of 10-6 to
10-7, for both average and maximum chemical concentrations in
soil, for a thirty year exposure period. This estimate is based
on conservative ingestion assumptions, i.e., ingestion of 200 mg
per day of soil for children ages one to six and 100 mg of soil
per day for individuals over the age of six. This estimate is
. also based on an exposure duration of 350 days per year for
twenty four years; it is unlikely that the ground will be free of
snow or unfrozen for the entire year in New Hampshire. The total
future, carcinogenic risk for potentially residents exposed only
to soil and surface water, using maximum concentrations for a
thirty year exposure period, is 8.43 x 10-6, which is within the
acceptable ri.sk range for Superfund sites.
With respect to non-carcinogenic risk, only the hazard indices
calculated for the ground water ingestion pathway exceed one,
signifying a potential for .noncarcinogenic effects if ground
water is ingested in the future. Using average concentrations,
the hazard quotient is 5.66 using shallow well data, and 4.23
using deep well data. For individual chemicals, only the hazard
indices for ingestion of arsenic and manganese in ground water
exceed one. Total hazard indices using maximum concentrations
are 42.1 (shallow well data), and 19 (deep well data). using
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PAGE 22
individual chemicals of concern exceed one. These chemicals are:
1,2 dichloroethylene, 4-methyl-2-pentanonet tetrachloroethylene,
toluene, naphthalene, arsenic, and manganese. Hazard indices for
all pathways other than ingestion of ground water are lower than
one.
The action level for lead in particulate form (unfiltered
samples) at the Site is exceeded in fifteen of thirty-eig~t
wells. In filtered samples, only one sample, of thirteen
collected, contained lead (28 parts per billion). The
distribution of lead in the area surrounding the Site indicates
that the concentrations of lead are natural. It is also
suggested that the concentrations found may be due to the sample
collection techniques used. It will be necessary to conduct
further sampling using different techniques to determine the
correct concentration of lead at the Site.
The Ecological Risk Assessment conducted during the Remedial
Investigation measured the potential ecological impacts of
contaminants from the Site on surrounding locations including
Swains Lake, the intermittent brook southwest of the Site, and
identified wetland areas to the west and northeast of the Site.
At least four wetland systems, two streams, and Swains Lake lie
within one-half mile of the Site. Surface water and sediment
samples were taken from these water bodies. Figure 10 on page 86
shows the location of these sampling points. Additional
information regarding the Ecological Risk Assessment are
available in Section 6.7 of the Remedial Investigation.
The only surface water apparently affected by the Site, as
determined by 1990 and 1991 analytical data, was the intermittent
stream southwest of the Site. The concentrations of contaminants
detected in the surface water of this stream do not appear to be
of concern for environmental receptors, but concentrations of
contaminants in the sediment could pose environmental risks16.
In particular, the concentration of 4,4-DDT in the stream's
sediment could impart biological effects to stream biota.
However, 4,4-DDT was not detected in any other media at the Site;
thus, it is unlikely this contaminant is site-related. A
comparison of the contaminants of concern selected for the
Ecological Risk Assessment and the maximum concentration detected
in the study area with appropriate guidelines. is in Table 13 on
. page 114. .
Contaminants of concern were not detected in the same
intermittent stream in 1991, thus reinforcing the assessment that
the intermittent stream is a limited exposure pathway for
environmental receptors. This intermittent stream is the result
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PAGE 23
surface. The intermittent nature of the stream is likely to
result in limited bioavailability of contaminants and limited
exposure pathways. Thus, the detected surface water and sediment
contaminant concentrations are not expected to pose significant
risks to aquatic components of this stream.
At this Site, hazardous substances have been released, and there
is a substantial threat of release, into the environment, and
response action is necessary to protect public health, welfare
and the environment. Actual or threatened releases of hazardous
substances from this Site, if not addressed by implementing the
response action selected in this ROD, may present an imminent and
substantial endangerment to public health, welfare, or the
environment. The potential use of contaminated ground water, as
well as the migration of groundwater, in both the overburden and
bedrock aquifers, from the Site poses a potential threat to
public health.
VII.
DEVELOPMENT AND SCREENING OF ALTERNATIVES
A. Statutory Ilequirements/Response Objectives
Under its legal authorities, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that are
protective of human health and the environment. In addition,
Section 121 of CERCLA establishes several other statutory
requirements and preferences, including:- a requirement that
EPA's remedial action, when complete, must comply with all
federal and more stringent state environmental standards,
requirements, criteria or limitations, unless a waiver is
invoked; a requirement that EPA select a remedial action that is
cost-effective and that utilizes permanent solutions and
alternative treatment technologies or resource recovery
technologies to the. maximum extent practicable; and a preference
for remedies in which treatment which permanently and
significantly reduces the volume, toxicity or mObility of the
hazardous substances is a principal element over remedies not
involving such treatment. Response alternatives were developed
to be consistent with these Congressional mandates.
Based on preliminary information relating to types of
contaminants, environmental media of concern, and potential
exposure pathways, remedial action objectives were developed to
aid in the development and screening of alternatives. These
remedial action objectives were developed to mitigate existing
and future potential threats to public health and the
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PAGE 24
For Human Health
.
Prevent the ingestion of ground water contaminated with
carcinogens in excess of concentrations for MCLs and a
total cancer risk of greater than 10~ to 10~;
.
Prevent the ingestion of ground water contaminated with
non-carcinogens in excess of MCLs, Action Levels or
concentrations that yield a hazard quotient greater
than 1;
.
Prevent the further migration of ground water
contaminated with carcinogens and non-carcinogens to
uncontaminated portions of the overburden and bedrock
aquifers; and
.
Restore ground water in the overburden and bedrock
aquifers to where concentrations of contaminants are at
or below those for MCLs, Action Levels and risk based
calculations, such that consumption of ground water is
protective of human health; and
.
Prevent the dermal contact, ingestion, or inhalation of
the contents of 12 drums of incinerator ash and three
VOC-contaminated barrels used for water filtration.
B. Technology and ~ternative Development and Screening
CERCLA and the NCP set forth the process by which remedial
actions are evaluated and selected. In accordance with these
requirements, a range of alternatives were developed for the
site.
With respect to ground water response action, the RIfFS developed
a limited number of remedial alternatives that attain site
specific remediation levels within different timeframes using
different technologies; and a no action alternative.
As discussed in Chapter 3 of the Feasibility Study, the RIfFS
identified, assessed and screened technologies based on
implementability, effectiveness, and cost. These technologies
were combined into management of migration (MM) alternatives.
--Chapter 30f the Feasibility Study presented the remedial
- alternatives developed by combining the technologies identified
in the previous screening process in the categories identified in
Section 300.430(e) (3) of the NCP. The purpose of the initial
screening was to narrow the number of potential remedial actions
for further detailed analysis while preserving a range of
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PAGE 25
Chapter 3 of the Feasibility Study.
In summary, of the eight management of migration remedial
alternatives screened in Chapter 3, five were retained for
detailed analysis. Table 14 on page 115 identifies the five
alternatives that were retained through the screening process, as
well as those that were eliminated from further consideration.
VIII.
DESCRXPTION OF ALTERNATrvES
This Section provides a narrative summary of each alternative
evaluated. A detailed tabular assessment of each alternative can
be found in Table 3-2 of the Feasibility Study.
Management of migration alternatives address contaminants that
have migrated from the original source of contamination. At the
Tibbetts Road Site, contaminants have migrated from ground water
off-site to the northeast and southwest. Contaminated ground
water initially flows radially away from the Site; however, this
flow coalesces into two general flows, one to the northeast and
another to the southwest. There is also a component of flow into
the bedrock aquifer. The Management of Migration alternatives
evaluated for the Site include a no-action alternative MM-1; a
limited action alternative MM-2, and three alternatives that
would capture and treat contaminated ground water.
MM-1 No-Action
This alternative was evaluated in detail in the Feasibility Study
to serve as a baseline for comparison with the other remedial
alternatives under consideration. Under this alternative, no
treatment or containment of contaminated ground water would occur
and no effort would be made to restrict potential exposure to
Site contaminants. Also under this alternative no monitoring of
ground water contamination or repair and improvement of the
existing water supply system would occur. The State of New
Hampshire ground water classification in this area is "GB",
suitable for drinking water use. The Federal ground water
classification in this area is II A, a current or potential
source of drinking water.
This alternative would rely solely on natural attenuation to
reduce contaminant concentrations to cleanup levels. The'length
of'time for the aquifers, beneath and surrounding the Site, to be
restored to beneficial use by natural attenuation is forty or
more years17. However, it is possible that natural attenuation
may not achieve cleanup levels even within this time frame. The
forty or more year time frame is dependent upon a homogenous
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None of these are present at the Site. In addition the presence
of NAPLs in the overburden aquifer will lengthen this estimate.
Estimated
Estimated
Estimated
Estimated
Estimated
Time for Design and Construction: ° weeks
Period for Operation: 40 or more years
Capital Cost: $0
Operation and Maintenance Cost (present worth): $0
Total Cost (present worth): $0
MM-2: Limited Action: Ground Water Monitorinq Proqram, Upqraded
Alternate Water SUPPly, Deed Restrictions, Natural Attenuation of
Contamination
MM-2 consists of minimal actions common to all alternatives
except MM-1. These actions involve the alternative drinking
water supply system, monitoring of surface water and ground
water, and Site security. The actions for the alternative
drinking water supply system are: upgrading, operation and
maintenance, and possible expansion of the water supply system to
other residents. The monitoring actions include institutional
controls to restrict ground water use, long-term monitoring of
the environment, and five-year reviews. Site security would be
provided by a fence, removal of the existing house~ removal of
surrounding debris, removal of twelve barrels of incinerator ash,
and removal of three contaminated carbon filtration units. All
materials removed from the Site would be. tested and transported
to the appropriate off-site disposal facility.
A component of MM~2 is the improvement and provisions for the
continued operation and maintenance of the alternate water supply
system. Improvements to the system would be made to ensure that
the system complies with all Federal and State drinking water
regulations during the life of the remedy. Improvements may also
include extending the water system to serve adqitional residents
whose water is affected by Site contaminants in ground water or
whose wells exert an influence on the ground water contaminant
plume and may cause it to migrate. There would be an annual
-assessment of water quality and updating of equipment. If the
water quality fails to achieve Federal and State drinking water
standards, changes would be made in equipment or treatment
methods to meet Federal and State drinking water standards.
~.Estimated
- Estimated
Estimated
. Estimated
$643,000
Estimated
Time for Design and Construction: 2 years
Period for Operation: 40 ~r more years
Capital Cost: 40 or more years
Operation and Maintenance Cost (present worth):
Total Cost (present worth):
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MM-5: Ground Water Extraction from Overburden and Weathered
Bedrock Aquifers. Vacuum Extraction of Overburden. On-site Metals
Removal and Ultraviolet/Chemical Oxidation Treatment of Orqanic
Contaminants. Off-site Recharqe
This alternative would implement the all of t~e actions listed
for alternative MM-2 and would also recover and treat
contaminated ground water. These elements are:
.
design and construction of ground water recovery
trenches or wells and a ground water treatment plant;
.
design and construction of a vacuum extraction system
and an air treatment system;
.
treatment of contaminated ground water to levels
protective of human health and the environment;
. discharge of treated ground water to off-site recharge
.-.- --be'ds - in the overburden' aquifer; and the discharge of
air from the vacuum extraction system through a carbon
treatment system to the atmosphere;
.
long-term monitoring of ground water and surface water
quality;
.
correct deficiencies in the alternate ground water
supply system and provide for the long-term ability of
the system to meet all Federal and State regulatory
standards until the remedy is protective;
.
the imposition of deed restrictions to prevent the use
of the bedrock and overburden aquifers during the
cleanup period;
.
removal of twelve -barrels of incinerator ash residue
and three barrels of granular activated carbon to an
off-site disposal facility; and .
.
removal of the existing on-site building and debris to
access the areas of contamination more efficiently, to
increase the efficiency of vacuum extraction, to better
provide for surface water runoff, and to eliminate a
potential exposure pathway.
In implementing this alternative, a period of design and
construction of the ground water recovery apparatus and a water
treatment plant would occur over a two to three year period.
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7), would capture and treat contaminated ground water in the
overburden and weathered bedrock aquifer. They differ primarily
in the treatment method to be used and in disposal of treated
ground water. Each of the alternatives MM-5, MM-6, and MM-7
would address contaminants in the competent bedrock aquifer
through natural attenuation. .
In the overburden aquifer two means of contaminant recovery would
be used: vacuum extraction on-site and a system of trenches
and/or wells to intercept contaminants migrating from the Site.
The area of attainment for reducing contaminants in the
overburden aquifer to levels protective of human health and the
environment would be the entire area of the plume as identified
in Figure 16 on page 92. The time necessary for attaining the
cleanup levels over the entire Site is estimated to be twenty
years. This estimate does not include the effects of the soil
vacuum extraction system which should significantly reduce the
cleanup time. The vacuum extraction and dewatering system will
operate in the center of the worst contamination and will remove
VOCs from the overburden aquifer more rapidly than pumping alone.
Therefore, the twenty year cleanup time for the overburden
aquifer is very conservative, and improves greatly over the time
calculated for alternatives MM-1 and MM-2 (more than forty
years) .
In the overburden aquifer, contaminants migrating from the Site
would be intercepted by one of two ground water intercept
systems. Each system would lie on one side of the surface water
divide. The construction of these ground water intercept systems
would recover contaminated ground water migrating in the upper
overburden and would be keyed into the lower overburden. Each
ground water intercept system would consist of either trenches or
a network of extraction wells arrayed to intercept the same
ground water plume as the trenches. These ground water
interception systems would be installed in the overburden aquifer
in such a way as to minimize disturbance to adjacent private
residences while effectively capturing the contaminated ground
water plume to prevent further migration of contamination. The
area of attainment of cleanup levels in the overburden aquifer is
shown in Figure 16 on page 92.
Vacuum extraction would use ground water recovery wells or
.trenchesto dewater the upper twenty feet of the aquifer, then
separate wells or trenches would be used to apply a vacuum to the
dewatered overburden soils. This vacuum would cause VOCs and
some SVOCs to evaporate and migrate rapidly to the vacuum
devices. This vacuum will also enhance the recovery of
contaminated ground water. VOCs in the air stream of the vacuum
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RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 29
prior to the discharge of that air to the atmosphere. Those
carbon absorption units would be removed from the Site for
disposal and replaced once they are ineffective in capturing
contaminants. Contaminated ground water captured by the vacuum
extraction system would be treated in the ground water treatment
system.
Vacuum extraction would be employed on those portions of the Site
where high concentrations of contaminants have indicated the
possible presence of non-aqueous phase liquid contaminants.
Vacuum extraction is most efficient in ~ighly contaminated areas.
Vacuum extraction will also be an effective means to recover
. LNAPLs or DNAPLs, if any exist, that remain in interstitial
waters above the lowered water table. If NAPLs exist at the
Site, they are most likely LNAPLs that will remain on the top of
the water table. Either dewatering of the on-site aquifer or
vacuum extraction will recover these contaminants rapidly.
-_. Cont-aminat-ed-g~-G-und .wa.ter-in the weathered bedrock aquifer would
be recovered through extraction wells positioned to the northeast
of the Site. The weathered bedrock zone is approximately thirty
feet below the ground surface and thirty feet thick in the area
intended for extraction. The weathered bedrock zone is
characterized by a high number of horizontal and steeply dipping,
oxidized fractures. The area of attainment of cleanup levels in
the weathered bedrock aquifer is shown on Figure 17 on page 93.
The calculated cleanup time for the weathered bedrock alone is
approximately fifteen years for alternative MM-5, MM-6, and MM-7.
Under alternatives MM-1 and MM-2 the cleanup time is
approximately thirty years for just the weathered bedrock.
No extraction of contaminated ground water from the competent
bedrock will occur because the contaminant concentrations are low
and declining. An earlier discussion beginning on page 14
describes the migration of contaminants into the competent
bedrock aquifer. Contamination in the competent bedrock wells
has been decreasing over time. In 1985, the six contaminated
competent bedrock wells had average concentrations of 187 ppb of
TCE and 45 ppb of benzene. In 1991, these average concentrations
fell to 40 ppb and 22 ppb for TCE and benzene respectively. Of
the six contaminanted competent bedrock wells only one well, 35R
which is in the area in which contaminated ground water is
migrating into the bedrock, showed an increase in contaminant
concentrations. Finally, twelve additional bedrock wells, not
contaminated above MCLs, encircle the contaminated wells.
Attainment of the cleanup levels through natural attenuation,
although not modeled due to the complexity of the ground water
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within the cleanup time for both the overburden and weathered
bedrock aquifers. This is because the active components of the
remedy, the recovery of contaminated ground water in the
overburden and weathered bedrock aquiferrs, will eliminate the
further introduction of contaminants into the competent bedrock
aquifer. Extrapolating the present decline in contamination
within the competent bedrock assuming that migration from the
contaminated overburden aquifer has ceased (ground water recovery
commenced) yields an approximate time of less than six years to
achieve cleanup levels in the competent bedrock aquifer.
Monitoring of the bedrock aquifer will assess the achievement of
those goals. Adaptations would be made to the current bedrock
monitoring system to obtain a more accurate picture of the.
subsurface contamination. These adaptations would include the
use of different types of packers to isolate individual
fractures, the installation of additional we+ls, and the
abandonment or modification of existing wells that are improperly
constructed.
The recovered contaminated ground water and air (from the vacuum
extraction process) would be conveyed to a central treatment
building. Figure 19 on page 95 displays a conceptual diagram of
the ground water interception trenches or wells, the position of
the vacuum extraction system, and the location of ground water
recovery in the weathered bedrock aquifer.
Recovered ground water would be brought to the surface and sent
to an on-site treatment facility. The treatment process is in
two-stages. The first stage is metals precipitation and removal
through the addition of chemical agents and the use of physical
processes. The second stage is destruction of VOCs and SVOCs
through photo-catalyzed oxidation or ultra-violet oxidation (UV-
oxidation). In metals removal, chemical additives and other
physical processes would remove dissolved and particulate
arsenic, manganese, iron, and other metals. Following metals
removal, ultraviolet light (UV) and an oxidizing agent, either
ozone or hydrogen peroxide or a combination of both, would
destroy the remaining organic compounds (especially TCE). If
ozone is used as an oxidant, air discharged from the treatment
system would first pass through a catalytic air treatment system
to remove ozone and any VOCs. UV-oxidation coupled with metals
treatment would reduce the concentration of contaminants in
treated ground water below the cleanup levels and would meet any
additional discharge requirements. Figure 20 on page 96 depicts
the treatment system proposed for this alternative.
After the appropriate testing of the treated ground water,
disposal would occur in an off-site recharge bed located on a
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Estimated Time for Design and Construction: 2 to 3 years
Estimated Time for Operation: approximately 20 years
Estimated Capital Cost: $2,228,000
Estimated Operation and Maintenance Cost (present worth):
$2,170,000
Estimated Total Cost (present worth): . $4,398,000
MM-6: Ground Water Extraction from Overburden and Weathered
Bedrock Aquifers, Vacuum Extraction of Overburden, On-site Metals
Removal, Treatment of Orqanic Contaminants Usinq Air Strippinq,
Discharqe to Surface Water: .
MM-6 is similar to alternative MM-5 in that it recovers Site
contaminants through a ground water recovery system and vacuum
extraction system, and includes the components of alternative MM-
2. However, alternative MM-6 differs from alternative MM-5 with
respect to the treatment process for volatile organic compounds
(VOCs) arid in the discharge of treated ground water. The
components of MM-6 which differ from alternative MM-5 are:
.
volatile organic compounds in recovered ground water
would be captured by an air stripping unit complemented
by carbon absorption units to reach cleanup levels for
organic contaminants; and
.
treated g~ound water would be discharged to the Bellamy
River, approximately one-mile east of the Site.
The air stripper would consist of a tower filled with plastic
packing material. Air would be blown counter-current to the flow
of the ground water to strip VOCs. Exhaust gases would then be
treated to remove contaminants by carbon absorption. The water,
once treated in the air stripper, would be further treated by
carbon absorption to removeSVOCs.This proposed treatment
system, coupled with the metal treatment process, would attain
the cleanup levels in the treated ground water prior to
discharge. .
A key element of this alternative is the discharge of treated
ground water to the Bellamy River. The Bellamy River is
cla5sified by the State of New Hampshire as a class A surface
water body, suitable for d~inking water purposes. A six-inch
pipe discharge line would be constructed from the Site, along
Tibbetts Road, and then along Hall Road to the outfall, a
distance of 5,400 feet. The implementation of this alternative
would be similar to alternative MM-5. However, this alternative
would need to attain additional standards such as the Ambient
Water Quality Criteria (AWQC) under the Clean Water Act and
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discharges. The Federal Clean Water Act, 33 USC 1251, and the
State of New Hampshire Surface Water discharge regulations, RSA
485-A:8, regulate the discharge of treated waters to a class A
surface water body. The ground water treatment process would be
able to meet the AWQC and State of New Hampshire standards.
The time necessary for MM-6
the same as for alternative
approximately twenty years,
techniques are identical.
to achieve cleanup levels would be
MM-5, a conservative estimate of
because the ground water recovery
Estimated Time for Design and Construction: 2 to 3 years
Estimated Period for Operation: approximately 20 years
Estimated Capital Cost: $1,897,000
Estimated Operation and Maintenance Cost (present worth):
$2,769,000
Estimated Total Cost (present worth): $4,666,000
MM-7: Ground Water Extraction from Overburden and Weathered
Bedrock Aquifers, Vacuum Extraction in the Overburden, On-site
Metals Removal and Ultraviolet/Chemical Oxidation Treatment of
Orqanic Contaminants, and Iniection Well Recharqe
This alternative is nearly identical to alternative MM-5. The
only component of MM-7 which differs from alternative MM-5 is:
.
discharge of treated ground water to bedro'ck and
overburden injection wells.
After the appropriate testing of the treated ground water,
injection wells would convey the treated water into the bedrock
aquifer and, on a seasonal basis, into the overburden aquifer.
The injection of the treated ground water would serve a number of
purposes:
.
when injected into the competent and weathered bedrock
aquifers it would provide an additional hydraulic
barrier, by reversing hydraulic gradients, to the
further migration of contaminated ground water into and
through the competent and weathered bedrock aquifers;
.
enhance the recovery of contaminated ground water when
injected into the weathered bedrock aquifer 9r the
overburden aquifer by steepening gradients and
therefore flow to recovery wells; and
.
provide a means of disposing of treated water without
modifing the hydraulic regimes of any surface water
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Seasonal recharge into the overburden aquifer would be used to
facilitate recovery of contaminants in the overburden ground
water recovery system. This seasonal recharge system would
operate during those periods in which the water table and the
rate of infiltration is low. This alternative would need to
comply with the substantive portions of the Safe Drinking Water
Act (42 USC 3000(f» Underground Injection Control Regulations
and the State of New Hampshire Revised Statute 485C in the
injection of treated ground water into ground water at the Site.
These requirements would not necessitate additional ground water
treatment prior to discharge.
The tim~ required for alternative MM-7 to achieve cleanup levels
is similar to MM-5 and MM-6. However, the use of treated water
to enhance the recovery and containment of contaminated ground
water in the overburden and weathered bedrock aquifer should
further decrease the time necessary to attain cleanup levels to
an even greater degree.
Estimated Time for Design and Construction: 2 to 3 years
Estimated Period for Operation: approximately 20 years
Estimated Capital Cost: $1,729,000 .
Estimated Operation and Maintenance Cost (net present worth):
$2,047,000
Estimated Total Cost (net present worth): $3,776,000
IX.
SOMMAllY 01' THE COMPARATIVE ANALYSIS OF ALTERNATIVES
Section 121(b) (1) of CERCLA presents several factors that at a
minimum EPA is required to consider in its assessment of
alternatives.. Building upon these specific statutory mandates,
the National Contingency Plan articulates nine evaluation
criteria to be used. in assessing the individual remedial
alternatives.
A detailed analysis was performed on the alternatives using the
nine evaluation criteria in order to select a Site remedy. The
following is a summary of the comparison of each alternative's
strength and weakness with respect to the nine evaluation
criteria. These criteria are summarized as follows:
Threshold Criteria
The two threshold criteria described below must be met in
order for the alternatives to be eligible for selection in
accordance with the NCP.
1.
Overall protection of human health and the
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provides adequate protection and describes how
risks posed through each pathway are eliminated,
reduced or controlled through treatment,
engineering controls, or institutional controls.
2.
Compliance with Applicable or relevant and
appropriate requirements (ARARS) addresses
or not a remedy will meet all of the ARARs
other Federal and State environmental laws
provide grounds for invoking a waiver.
whether
of
and/or
Primary Balancina Criteria
The following five criteria are utilized to compare and
evaluate the elements of one alternative to another that
meet the threshold criteria.
3.
Long-term effectiveness and permanence addresses
the criteria that are utilized to assess
alternatives for the long-term ef.fectiveness and
permanence they afford, along with the degree of
certainty that they will prove successful.
Reduction of toxicity, mobility, or volume through
treatment addresses the degree to which
alternatives employ recycling or treatment that.
reduces toxicity, mobility, or volume, including
how treatment is used to address the principal
threats posed by the site.
4.
5.
Short term effectiveness addresses the period of
time needed to achieve protection and any adverse
impacts on human health and the environment that
may be posed during the construction and
implementation period, until cleanup goals are
achieved.
6.
Implementability addresses the technical and
administrative feasibility of a remedy, including
the availability of materials and services needed
to implement a particular option. .
Cost includes estimated capital and Operation
Maintenance (O&M) costs, as well as present-worth
costs.
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Modifvina Criteria
The mo~ifying criteria are used on the final evaluation of
remedial alternatives generally after EPA has received
public comment on the RIfFS and Proposed Plan.
8.
State acceptance addresses the State's position
and key concerns related to the preferred
alternative and other alternatives, and the
State's comments on ARARs or the proposed use of
waivers. .
9.
Community acceptance addresses the public's.
general response to the alternatives described in
the Proposed Plan and RIfFS report.
A detailed tabular assessment of each alternative according to
the nine criteria can be found in Table 4-6 of the Feasibility
Study.
Following the detailed analysis of each individual alternative, a
comparative analysis, focusing on the relative performance of
each alternative against the nine criteria, was conducted. This
comparative analysis can be found in Section 4.7 of the
Feasibility Study.
.
The section below presents the nine criteria and a brief
narrative summary of the alternatives and the strengths and
weaknesses according to the detailed and comparative analysis.
OVERALL PROTECTION OF !roMAN HEALTH AND. THE ENVIRONMENT
Alternative MM-1, no action, is not protective of human health
and the environment because contaminants would continue to
migrate in ground water unabated and unmonitored. Actions
undertaken for alternative MM-1 would not monitor the migration
of ground water contaminants to ensure that additional wells do
not become contaminated, nor would it ensure a drinking water
supply that is in compliance with all Federal and State drinking
water regulations.
Alternative MM-2, limited action, provides protection to human
health by instituting administrative controls to prevent access
to and contact with contaminated ground water. In addition, a
ground water and surface water monitoring program would allow
regulators to track the status and migration of contaminants.
Alternative MM-2 would also provide protection through the use of
institutional controls or similar restrictions on ground water
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The existing potable water supply system would be upgraded and
operation and maintenance would be continued to provide a safe,
potable supply to potentially affected residences. Alternative
MM-2 may not be protective of the environment if migrating ground
water were to discharge to a surface water body introducing
contaminants whose concentrations exceed AWQC.
Both MM-1 and MM-2 propose to allow ground water to migrate and
further contaminate the overburden and bedrock aquifers. EPA's
Ground Water Protection Strategy outlined beginning on page 8732
of the NCP outlines a preference for rapid restoration, where
possible, of ground waters that are currently, or likely in the
near term to be the source of a drinking water supply. The.
current water supply system serves only that area within
approximately one-half mile of the Site. Existing homes, and
potential residential areas outside of this service district
currently use, or will use, uncontaminated ground water that is
hydraulically connected to the Site. Continued migration of Site
contaminants may eventually contaminate these residential wells
resulting in the ingesti6nof contaminated ground water.
Alternatives MM-S, MM-6, and MM-7 are protective of human health
and the environment by capturing and treating contaminated ground
water in the overburden and bedrock aquifers. Alternatives MM-S,
MM-6, and MM-7 all include the components of alternative MM-2 to
ensure a drinking water supply that complies with all Federal and
State regulations.
All alternatives, except MM-1, are equally protective in
providing for the ~emoval and off-site. disposal of barrels
containing incinerator ash and VOC-contaminated activated carbon.
COMPLIANCE WITH ARARs
Alternatives MM-S, MM-6, and MM-7, would achieve chemical-
specific ARARs, MCLs, and non-zero MCLGs in the overburden and
bedrock aquifers within twenty years. Further, the remedial
activities proposed by alternatives MM-5, MM-6, and MM-7 would be
designed and performed to meet location-specific and action-
specific ARARs. Certain chemical-specific ARARs, although
perpaps not all, may be attained under alternatives MM-1 and MM-2
through natural attenuation; however, these concentrations would
not be achieved for forty ~r more years.
Alternatives MM-1 and MM-2 would not comply with ARARs and
guidance relating to the continued off-site migration of
contaminants above the maximum contaminant levels (MCLs)
established under the Safe Drinking Water Act. The migration of
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Ground Water Protection Strategy as established in the National
Contingency Plan 40 CFR ~300.430(a) (1) (iii) (F) . The continued
existence and migration of Site contaminants in the overburden
and weathered bedrock aquifers would not be in compliance with
Federal Hazardous Waste Regulations (40 CFR 264, Subpart F) or
New Hampshire Hazardous Waste Rules (Subtitle Env-Wm 500 and
700) .
LONG-TERM EFFECTrvENESS AND PE~NCE
AlternativesMM-1 and MM-2 would possibly afford long-term
effectiveness and permanence because if cleanup levels are
eventually attained through natural attenuation, after at least
forty years, little to no residual risk will be presented by the
Site. No additional risk would be created by treatment residuals
because these alternatives do not propose treatment.
Alternatives MM-5, MM-6 and MM-7 all provide long-term
effectiveness and permanence by removing the contaminants from
the ground water; ultimately destroying the organic contaminants,
and rendering the inorganic contaminants immobile by
consolidation and, if necessary, stabilization. In addition, the
migration of the plume would be halted so that no additional
drinking water supplies would be at risk.
Alternatives MM-5, MM-6, and MM-7 would provide comparable long-
term effectiveness and permanence for their respective discharge
options, because the prior treatment process would have achieved
cleanup levels.
Alternatives MM-5, MM-6, and MM-7 all provide long-term
effectiveness and permanence by removing contaminants from ground
water, destroying or capturing VOCs, and immobilizing metal
contamination. The magnitude of remaining risk on-site and the
area surrounding the Site would be low because the cleanup levels
are protective of human health and the environment. A low
magnitude of risk will occur off-site as metal residuals from the
treatment system will require off-site disposal. Contaminated
carbon absorption units from the vacuum extraction system will
also be generated by alternatives MM-S, MM-6, and MM-7 that will
also create a low magnitude of risk at an appropriate off-site
disposal facility operating in compliance with all Federal and
State regulations. No treatment residuals, will remain on-site to
_generate risk to human health.
REDUCTION OF TOXICITY, MOBILITY, AND VOLUME THROUGH TREATMENT
Alternatives MM-1 and MM-2 offer no reduction in toxicity,
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attenuation would result in a very slow reduction of
concentrations of contaminants via biological and geochemical
processes and dilution over a forty year period or longer.
Natural processes and dilution may not reduce toxicity, mobility,
or volume. Dependent upon the type of natural reduction,
toxicity and mobility may actually increase if other compounds
are created by biological metabolism or other geochemical
processes. The volume of contaminated water will actually
increase with time as the overburden and weathered bedrock
contaminant plumes continue to migrate.
Alternatives MM-1 and MM-2 also fail to satisfy EPA's Ground
Water P~otection Strategy contained in the NCP because it fails
to halt the further migration of contaminated ground water at
concentrations that would pose a hazard to human health and the
environment into an aquifer that is currently in use. .
Alternatives MM-S, MM-6 and MM-7 would substantially reduce the
toxicity, mobility, and volume of the contaminant~ thr~ugh
treatment. Alternative MM-6 would employ chemical precipitation
to immobilize the inorganic contaminants, and the physical
processes of air stripping and carbon adsorption to concentrate
the organic contaminants prior to destroying them by off-site
incineration. Alternatives MM-S and MM-7 would destroy the
organic contaminants on-site in a UV/chemical oxidation process,
and would also employ chemical precipitation to immobilize the
inorganic contaminants. All three of these alternatives would
recover and destroy approximately one thousand pounds of VOCs in
irreversible processes.
The proposed location of the extraction system for alternatives
MM-S, MM-6, and MM-7 is designed to withdraw contaminated ground
water from the overburden and weathered bedrock. When the
contaminated ground water migration pathway is diverted towards
the extraction system, migration of the contaminant plume will be
reduced or eliminated, thereby reducing mobility of the
contaminants. As contaminants are removed from the ground water
by the treatment process, the contaminant vo~ume and toxicity in
the ground water on-site would be reduced. With remediation of
the overburden and weathered bedrock, the expectation is that
natural attenuation will reduce the concentrations in the lower
bedrock to MCLs well within the estimated cleanup time of the
overburden and weathered bedrock aquifers. Residual
contamination in the overburden aquifer, partitioned to the soil,
would be small since the overburden aquifer contains a low
organic content.
.Alternatives MM-S, MM-6, and MM-7 use the same treatment process
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chemical sludges. These sludges would contain the chemicals used
to effect precipitation, captured particulate matter extracted
from the ground water, and the formerly dissolved or suspended
metals. The volume of dewatered chemical sludges would be
approximately two to four cubic feet per day at a concentration
of 30% solids. Over the life of the remedy, twenty years, this
would yield a total of between 14,600 to 29,200 cubic feet of
sludges under the worst case scenario (concentrations of metals
do not reduce over time). This sludge, after testing, would be
disposed of at an appropriate off-site facility operating in
compliance with all Federal and State requirements.
Alterna~ives MM-5 and MM-6, using uv-oxidation, and alternative
MM-6, using air stripping, will destroy or capture respectively,
90 to 99+% of various organics found at the Site. MM-5 and MM-7
are equivalent in that they would destroy and immobilize the same
amount of hazardous substances. However, in alternative MM-6
VOCs would be transferred from the ground water to the air and
the resulting VOCs in the air stream would be captured in carbon
absorption units. SVOCs, not susceptible to air stripping would
be recovered by carbon absorption in the treated water from the
air stripper. Therefore, MM-6 will not destroy, but capture
contaminants for off-site disposal or destruction.
SHORT-TERM EFFECTrYENESS
Alternative MM-l has no risks created by remedial action. The
remedial action is considered to be natural attenuation of the
contaminated ground water which will occur over at least forty
years. No deed restrictions or improvements in the water line
will occur, therefore during this time the potential exists for
contaminated ground water to be used for drinking water purposes.
The limited actions taken by alternative MM-2 would create minor
exposure hazards for workers during demolition of the house,
disposition of the drummed waste, and monitoring of the wells;
however, the workers could easily be protected with conventional
personal protection equipment designed for this service.
Furthermore, an upgraded/improved water treatment system would
provide a better long term potable water supply for potentially
affected residents. The improvement and operation of the
alternpte water supply system would ensure that residents are not
exposed to ground water contaminants. The short-term effects
would be of the same duration as MM-l, greater than forty years.
Alternatives MM-5, MM-6 and MM-7 would provide better overall
short-term effectiveness compared to Alternatives MM-l and MM-2,
because the pump and treat technology would return ground water
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MM-1 and MM-2 (twenty years rather than forty or more years if at
all), and minimize the plume migration. However, the
construction of alternatives MM-S, MM-6, and MM-7 would create
more significant short-term hazards related to VOC emissions,
particulate emissions, surface runoff, and general construction
hazards related to deep trenching operations or well drilling.
Subject to design considerations, some soil with low-level
contamination would have to be excavated to install the ground
water extraction system. Measures would be taken to control
direct contact and inhalation hazards to the public. Potential
adverse environmental impacts that may result from excavation
activities would be minimized by limiting exposed areas of soil,
erosion/sedimentation control, and covering of exposed soil.
Workers performing excavation activities under these alternatives
would be dressed in the appropriate personal protection
equipment. The soil at the surface will be tested appropriately
after being brought to finish grade to ensure that the remedy
remains protective and poses no short-term risk to human health
and the environment.
VOC emissions from vented tanks and the air stripper proposed in
alternative MM-6 would be controlled with activated carbon. Off-
site transportation, treatment, and disposal spent carbon, and
residues from the metals removal process may pose potential risks
to public health, but these risks are not considered significant.
Emissions from treatment equipment during operation would be
controlled using suitable technology. .
Compared to Alternatives MM-S and MM-7, Alternative MM-6 would
have some additional potential impact to workers, the community,
and the environment, because of the off-site transport of
relatively large loads of spent activated carbon. This impact is
not considered significant, since the carbon would be
. containerized, the contaminants are not easily desorbed.
However, Alternatives MM-S and MM-7 would have the potential to
~ impact workers in a way that Alternative MM-6 would not; i.e.,
. workers would need to exercise additional care when operating the
.UV/chemical oxidation system, because the process uses oxidizing
agents to complete the treatment.
The additional impacts to short-term effectiveness associated
with the discharge component of Alternatives MM-S and MM-7 would
not. be considered significantly different from each other.
However, Alternative MM-6 would involve the construction of a
'one-mile-Iong underground pipeline alongside and beneath Tibbetts
Road and Hall Road, eventually discharging at the Bellamy River
southeast. of Swains Lake. The construction would be planned and
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to minimize the emission of particulate and VOC emissions to the
community.
IMPLEMENTABILITY
Alternative MM-1 would be easiest to implement, since no action
would be required.
Alternative MM-2 would require some cooperative action between
regulatory agencies to maintain the monitoring program and
implement the institutional controls. Technically,
implementation of Alternative MM-2 would be straightforward.
Implementability issues regarding Alternative MM-2 would also be
reflected in all subsequent alternatives, which all incorporate
the components of MM-2.
In complying with EPA's Ground Water Protection Strategy in the
NCP it is necessary to assess if rapid restoration of the ground
water is possible. The greatest majority of contaminants are
within the upper overburden aquifer within twenty to thirty feet
of the ground surface in a relatively permeable environment.
NAPLs, if they exist, most likely will consist of LNAPLs in
isolated areas. DNAPLs, while not likely to exist at the Site,
would occur at the upper overburden / aquitard interface that is
within twenty to thirty feet of the surface. Vacuum extraction,
coupled with dewatering of the overburden aquifer will be an
efficient and effective means of removing contaminated ground
water.
Alternatives MM-5,' MM-6 and MM-7 would each use conventional
techniques for construction of the ground water extraction
system. These alternatives would use treatment technologies that
have been proven successful at other Superfund sites. Air
stripping and activated carbon adsorption have been widely used,
and UV / chemical oxidation has been successfully' demonstrated in
the EPA SITE Program. Consequently, operation of these systems
would not involve any unusual practices. Off-site facilities are
readily available for the regeneration of spent activated carbon;
and facilities with sufficient capacity are also available for
the treatment, if necessary, and disposal of chemical sludges
whi~h would' be produced by the metals pretreatment system.
The air stripping and carbon adsorption systems could be designed
without treatability testing, but since treatment to achieve MCLs
will be required, limited testing will be conducted before final
design. The UV/chemical oxidation process has not been as widely
applied as air stripping and carbon adsorption, and would need to
be pilot tested at the Site before final design. The discharge
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MM-6, and MM-7 would meet the substantive requirements to
discharge air back to the atmosphere following appropriate
treatment.
The discharge component of Alternative MM-6 is technically
implement able using standard construction techniques.
Administratively, rights-of-way would need to be obtained for the
underground discharge line and the off-site pump station, and
NPDES permit requirements would have to be met for the surface
water discharge. Routine effluent monitoring would be required.
For these reasons, this discharge option could be the most
difficult to implement.
Alternative MM-7 would involve the installation of injection
wells on-site and would be technically easy to implement. On-
site injection wells could be the easiest discharge option to
implement. .
COST
No costs are associated with Alternative MM-1.
Alternative MM-2 has a total estimated present worth cost of
$1,025,900, including capital costs of $383,400, and present
worth O&M costs of $642,500 for the monitoring program and water
supply system.
Evaluating the cost-effectiveness of alternatives MM-l or MM-2
against alternatives MM-5, MM-6, or MM-7 in light of the guidance
provided by EPA's Ground Water Protection Strategy in the NCP
finds that either of alternatives MM-5, MM-6, or MM-7 would be
cost-effective. Alternatives MM-5, MM-6, and MM-7 would restore
ground water to beneficial use in the competent portion of the
bedrock aquifer in far less time, perhaps within six years or
less, than alternatives MM-l and MM-2. In the overburden aquifer
the contaminants would remain restricted to the Site during
implementation of alternatives MM-5, MM-6, and MM-7; thereby
removing the threat to the competent portion of the bedrock
aquifer. The life of the remedy for these alternatives is twenty
years or less; however, costs were calculated on a conservative
basis.
Alternative MM-5 has a total estimated present worth cost of
$4,397,690, which is 6% lower than that of Alternative MM-6. The
capital cost for Alternative MM-5 is $2,228,190, which is higher
than that of Alternative MM-6i however, the present worth O&M
costs are $2,169,500, which is 28% lower than the O&M costs for
Alternative MM-6. If activated carbon should be necessary to
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increase the O&M costs nearly enough to offset the estimated cost
difference between the alternatives.
Alternative MM-6 has a total estimated present worth cost of
$4,666,130, including capital costs of $1,897,4~0, and present
worth O&M costs of $2,769,070. A major variable in the cost of
this alternative is the cost of regenerating the activated
carbon. Regardless of variation in carbon usage, Alternative MM-
5 would be. expected to remain lower in cost than Alternative MM-
6.
Alternative MM-7 has an estimated additional capital cost beyond
treatment of $70,000 to install injection wells with associated
pump and piping. The O&M costs for power and pump maintenance
would amount to less than $20,000 on a present worth basis,
assuming an annual cost of about $2,000. Alternative MM-7 has an
estimated cost lower than either MM~5 or MM-6, the total
estimated present worth being $3,775,660.
Key cost variables for alternatives MM-S, MM-6, and MM-7 include
material and construction costs for the interceptor trench, the
collection drain, and treatment equipment, and construction and
operation costs for the ground water treatment systems. With
respect to cost sensitivity, the time required to complete ground
water recovery and treatment appears to have the largest
potential cost impact on this alternative in terms of O&M costs,
including costs for ground water monitoring, chemicals, and
sludge disposal. While the remedy is expected to be completed in
twenty years, cost analyses are completed for a thirty year time
frame to be conservative, as actual operating times cannot be
exactly determined.
Capital costs for ground water treatment equipment vary less than
O&M costs, but depend on the design flow rate. Variations in the
actual flow rate and final constituent concentrations could
affect equipment sizing in the final design, and could thereby
affect costs. A pumping test on the ground water collection
drain after construction would provide the best estimate of the
final expected flow rate to the treatment system.
Estimated costs for each remedial alternative are summarized in
Table 15 on page 117.
Alternative MM-7 is the least expensive of those alternatives
that actively recovers and treats contaminated ground water. The
primary cost savings are the use of an on-site bedrock injection
well and the operating efficiency of the uv-oxidation treatment
system. With the uv-oxidation treatment for ground water
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for carbon treatment of any of the effluent, liquid or air.
There are significant differences in cost as noted in previous
sections that detail each alternative. While MM-1 has no capital
or operation and maintenance cost, MM-2 will cost about one
million dollars, MM-5 and MM-6 over four million dollars, and
MM-7 somewhat under four million dollars. The capital, operation
and maintenance, and total cost for each alternative is provided
as part of the description for each alternative in the preceding
sections. .
State Acceptance
The New Hampshire Department of Environmental Services (DES) has
been involved with the Site as summarized in Section II of this
document titled "Site History and Enforcement Activities". The
New Hampshire DES has reviewed this document and concurs with the
alternative selected for the remedy as documented in the attached
Declaration of Concurrence.
Community Acceptance
The comments received during the public comment period and the
discussions during the Proposed Plan and public meeting are
summarized in the attached document entitled "The Responsiveness
Summary" (Appendix D). Comments were received from the Ford
Motor Company, a potentially responsible party. No comments were
submitted by the citizens. The potentially responsible party
commented on the remedy and suggested that EPA choose the limited
action remedy, MM-2.
x.
TBJ: SELECTED RBMEDY
The remedy proposed for the Tibbetts Road Site, MM-7, addresses
all of the contamination at the Site. The remedy will improve
and potentially extend the present drinking water treatment
system, continue environmental monitoring, remove containerized
treatment residuals that currently exist on-site, halt migration
of the contaminated ground water plume, and recover and treat
contaminated ground water from the overburden aquifer and the
weathered portion of the bedrock aquifer. The proposed remedy
will prevent further contamination of the competent portion of
the bedrock aquifer. A detailed description of the selected
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(.,
TIBBETTS .ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 45
A. Interim Ground Water Cleanup Levels
Interim cleanup levels have been established in ground water for
all contaminants of concern identified in the Baseline Risk
Assessment found to pose an unacceptable risk to either public
health or the environment. Interim cleanup levels have been set
based on the ARARs (e.g., Drinking Water Maximum Contaminant
Level Goals (MCLGs) and MCLs) as available, or other suitable
criteria described below~ Periodic assessments of the protection
afforded by remedi.al actions will be made as the remedy is being
implemented and at the completion of the remedial action. At the
time that Interim Ground Water Cleanup Levels identified in the
ROD and newly promulgated ARARs and modified ARARs which call
into question the protectiveness of the remedy have been achieved
and have not been exceeded for a period of three consecutive
years, a risk assessment shall be performed on the residual
ground water contamination to determine whether the remedial
action is protective. This risk assessment of the residual
ground water contamination shall follow EPA procedures and will
assess the cumulative carcinogenic and non-carcinogenic risks
posed by the ingestion of ground water.
If, after review of the risk assessment, the remedial action is
not determined to be protective by EPA, the remedial action shall
continue until either protective levels are achieved, and are not
exceeded for a period of three consecutive years, or until the
remedy is otherwise deemed protective. These protective residual
levels shall constitute the final cleanup levels for this Record
of Decision and shall be. considered performance standards for any
remedial action. .
Because the overburden and bedrock aquifers are a potential
source of drinking water, and were in fact used as a source of
drinking water in the area surrounding the Site until they became
contaminated, MCLs and non-zero MCLGs established under the Safe
Drinking Water Act are ARARs.
Interim cleanup levels for known, probable, and possible
carcinogenic compounds (Classes A, B, and C) have been
established to protect against potential carcinogenic effects and
to conform with ARARs. Because the MCLGs for Class A & B
compounds are set at zero and are thus not. suitable for use as
interim cleanup levels, MCLs have been selected as the interim
cleanup levels for these Classes of compounds. Because the MCLGs
for the Class C compounds are greater than zero, and can readily
be confirmed, MCLGs have been selected as the interim cleanup
levels for Class C compounds. Where neither a MCL or non-zero
MCLG exists, EPA has considered proposed MCLs or proposed non-
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PAGE 46
Interim cleanup levels for Class D and E compourtds (not
classified, and no evidence of carcinogenicity) have been
established to protect against potential non-carcinogenic effects
and to conform with ARARs. Because the MCLGs for these Classes
are greater that zero and can readily be confirmed, MCLGs and
proposed non-zero MCLGs have been selected as the interim cleanup
levels for these classes of compounds.
In situations where a promulgated State standard is more
stringent than values established under the Safe Drinking Water
Act, the State standard was used as the interim cleanup level.
In the absence of a Federal or State ARAR, or a standard-to-be-
considered (TBC) such as a proposed MCLG, proposed MCL, or other
suitable criteria (i.e., health advisory, state guideline), an
interim cleanup level was derived for each compound having
carcinogenic potential (Classes A, B, and C compounds) based on a
10-6 excess cancer. risk level per compound considering the
ingestion of ground water. In the absence of the above same.
standards and criteria, interim cleanup levels for ~ll other
compounds (Classes D and E) were established based on a level
that represent an acceptable exposure level to which the human
population including sensitive subgroups may be exposed without
adverse affect during a lifetime or part of a lifetime,
incorporating an adequate margin of safety (hazard quotient = 1)
considering the ingestion of groundwater. If a value described
by any of the above methods was not capable of being detected
with good precision and accuracy or was below what was deemed to
be the background value, then the practical quantification limit
or background value was used as appropriate for the Interim
Ground Water Cleanup Level.
Table 16 on page 118 and page 119 summarizes the Interim Cleanup
Levels for carcinogenic and non-carcinogenic contaminants of
concern identified in ground water.
One Site contaminant, arsenic, exceeds the risk range even at the
MCL. However, recent studies indicate that many skin tumors
arising from oral exposure to arsenic are non-lethal and that the
dose-response curve for the skin cancers may be sublinear (in
which case the cancer potency factor used to generate risk
estimates may be overestimated). It is Agency pOlicy to manage
these risks downward by as much as a factor of ten. As a result,
the carcinogenic risk for arsenic at this Site has been managed
as if it were one order of magnitude lower than the calculated
risk. Consequently, the risk level for arsenic in the above
table reflects a risk management factor.
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PAGE 47
In a memo issued on June 21, 1990 by the Office of Emergency and
Remedial Response and the Office of Waste Program Enforcement
recommended a cleanup level for lead of 15 ppb in ground water
used for drinking water. In June 1992 EPA promulgated treatment
methods, not an MCL, in the Final National Primary Drinking Water
Standards for lead. This regulation establishes treatment
techniques that are to be used when an action level of 15 ppb of
lead is exceeded at ten percent of the taps sampled. This
regulation does not contain a requirement to attain a specific
cleanup level; the rule contemplates that cleanup levels will be
determined based on site-specific analysis.
At this Site, the 15 ppb action level for lead in particulate
form (unfiltered samples) at the Site is exceeded in fifteen of
thirty-eight wells. Only one sample, of thirteen collected in
the filtered form, contained lead (28 parts per billion). The
distribution of lead in the area. surrounding the Site indicates
that much of the lead seen in the unfiltered form may not be
attributable to contamination emanating from the Site. Also the
concentrations found may be due to the sample collection
techniques used. Accordingly, before setting an interim cleanup
level for lead, it will be necessary to conduct further sampling
to determine the correct concentration of lead at the Site. A
monitoring program using a new method of sampling for metallic
contaminants will be instituted to determine the true background
at the Site and what the true long-term levels of lead are in the
area surrounding the Site. The samplinq method will be
representative of ground water in use for domestic purposes and
will eliminate the collection of both filtered and unfiltered
samples. Unless the data collected during the remedial design
indicate that lead is either not associated with the Site, or
that the present samples are not representative of true ground
water conditions, the final cleanup level will be 15 ppb.
While the interim cleanup levels listed above are consistent with
ARARs or suitable TBC criteria for ground water, a cumulative
risk that could be posed by these compounds may exceed EPA's
goals for remedial action. Consequently, these levels are
considered to be interim cleanup levels for ground water. At the
time that these Interim Groundwater Cleanup Levels identified in
the ROD (and any newly promulgated ARARs and modified ARARs which
call into question the protectiveness of the remedy) have been
achieved and have not been exceeded for a period of three
consecutive years, a risk assessment shall be performed on the
residual ground water contamination to determine whether the
remedial action is protective. This risk assessment of the
residual ground water contamination shall follow EPA procedures
and will assess the cumulative carcinogenic and non-carcinogenic.
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PAGE 48
of the risk assessment the remedial action is not determined to
be protective by EPA, the remedial action shall continue until
either protective levels are achieved and are not exceeded for a
period of three consecutive years, or until the remedy is
otherwise deemed protective. These protective residual levels
shall constitute the final cleanup levels for this Record of
Decision and shall be considered performance standards for any
remedial action.
All Interim Groundwater Cleanup Levels identified in the ROD and
newly promulgated ARARs and modified ARARs which call into
question the protectiveness of the remedy and the protective
levels determined as a consequence of the risk assessment of
residual contamination, must be met at the completion of the
remedial action. EPA has estimated that these levels will be
obtained within twenty years after implementation of the
management of migration remedy.
B. Description of Remedial Components
The remedy that EPA has selected, MM-7, will capture and treat
contaminated ground water and also contains all of the components
of MM-2, the limited action remedy. The recovery and treatment
of contaminated ground water is necessary to halt the migration
of contaminants from the Site and return the overburden and
bedrock aquifers to usable sources of drinking water within an
acceptable time period. .
The actions proposed under MM-2 and included in the proposed
remedy are:
.
upgrading and expansion of the water supply system
where necessary;
.
institutional controlsr if possible, on ground water
use for those residences added to the drinking water
supply;
.
long-term monitoring of the environment;
.
five-year reviews;
.
maintenance of a fence for security; and
.
removal of the existing house, surrounding debris,
twelve barrels of incinerator ash, and three
contaminated carbon- filtration units to an off-site
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Improvements to the drinking water supply system will be made to
ensure that the system complies with all Federal and State
drinking water regulations during the life of the remedy. These
improvements will be the installation of equipment of a permanent
nature sufficient to treat surface water for an estimated one
hundred residences and have the provision for expansion if
additional users enter the system. Allowances will be made to
permit the replacement or upgrading of equipment to meet any
applicable new Federal or State regulatory requirements.
Improvements will also include the installation of equipment to
ensure a continued supply of drinking water during emergency
periods (power outages, etc) over a reasonable period of time.
The specific details of the system improvements will be
determined after a thorough analysis of the systems deficiencies,
short-term and long-term needs, and regulatory requirements.
Improvements may also include extending the water system to serve
current and future residents whose wells are contaminated by Site
contaminants in ground water or whose wells exert an influence on
the ground water contaminant plume and may cause it to migrate.
Criteria considered prior to extension of the water line will be
contaminant types, likely migration route, and relative
concentration. Contaminants determined to be migrating from the
Site in ground water are listed in the Table 6-1 of the Remedial
Investigation. In those areas in which the extension of the
existing drinking water supply line is not possible, an
appropriate point of use filter or water treatment system may be
installed to provide domestic water. All residences that are
placed on the alternate water supply system will have
institutional controls, such as deed restrictions prohibiting the
withdrawal of ground water, as a condition for tying into the
system.
Long-term environmental monitoring will include sampling of
approximately twenty overburden and bedrock ground water
monitoring wells located on- and off-site, and at least two
surface water monitoring locations until cleanup levels are met
and maintained. A short-term design effort will be required to
ensure that the overburden aquifer and the bedrock aquifer are
monitored accurately. Modifications to existing wells,
abandonment 'of some existing wells, and drilling of new
monitoring wells may be required prior to monitoring being fully
implemented.
Long-term monitoring would record and allow evaluation of trends
in contaminant concentration and extent of contamination
migration. Monitoring well locations would be selected during
program design. Surface water monitoring locations would include
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PAGE 50
periodically, other selected nearby bodies of water. Ground
water monitoring will occur quarterly for the first two years
from the completion of the construction, semi-annually for the
next two years and annually for at least an additional twenty-six
years. At the conclusion of the fifth year of monitoring, EPA
will reevaluate monitoring requirements based on an assessment of
the time required for ground water quality to improve to meet
MCLs and the risk presented to human health and the environment.
The 1986 CERCLA amendments require review of conditions every
five years at NPL sites. All data obtained in the monitoring
program will be evaluated in the five-year reviews. These
reviews. will consider all relevant data and determine if
additional remedial actions are necessary.
The selected remedy includes the removal of the house and debris
piles. The removal of the house is necessary to improve access
over the Site, control surface water flow, improve the efficiency
of the vacuum extraction system, and eliminate an exposure
- pathway. The foundation may become an exposure pathway by
collecting contaminated ground water during periods of high water
table levels. The foundation of the former residence will need
to be filled and perhaps capped with an impermeable membrane to
minimize short-circuiting the vacuum extraction system and to
prevent a change in the existing hydraulic regime. The removal
of the debris pile is necessary to improve Site drainage and
acces.s over the Site. To protect the active measures of the
overall remedy a fence will be installed" to restrict unauthorized
access onto areas of the Site where active remedial measures
occur.
This remedy includes the removal of drums containing residues
from incinerated soil and spent activated carbon. The wastes
consist of twelve drums of incinerator ash from a removal action
and three drums of spent liquid phase activated carbon from
previous treatability testing. Previous testing by EPA has found
that the three drums of carbon are contaminated with high
concentrations of VOCS18. After testing, the carbon filters and
incinerator ash will be disposed of at an appropriate off~site
facility.
The active recovery of contaminated ground water includes the
following components:
.
ground water interception trenches or wells in the
overbu~den aquifer;
.
ground water recovery wells in the weathered portion of
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PAGE 51
.
a vacuum extraction system in the overburden aquifer;
.
a ground water treatment plant to treat contaminated
ground water recovered from the interception system and
the vacuum extraction system in the overburden aquifer,
and contamina~ed ground water from the weathered
bedrock wells;
.
an air treatment system to treat contaminated air
extracted from the dewatered portions of the overburden
aquifer by the vacuum extraction system;
.
treatment of contaminated ground water and air to
levels protective of human health and the environment;
and
.
discharge of treated ground water to bedrock and
overburden injection wells, and the discharge of air
from the vacuum extraction system to the atmosphere;
Site preparation work will include improvements to Site security
and access. Ground water extraction will be required to dewater
the vacuum extraction area in the overburden aquifer, intercept
two ground water contaminant plumes in the overburden aquifer,
and recover contaminated ground water in the bedrock aquifer.
The ground water recovery system has three components referred to
in the remedy:
.
Ground water interception system which will intercept
and capture contaminated ground water migrating off-
site in the overburden aquifer;
.
Ground water dewatering system which will dewater the
overburden aquifer in the area in which vacuum
extraction of the overburden is occurring; and
Ground water recovery well system which will recover
contaminated ground water from the weathered bedrock,
much of this ground water be recharge received from the
contaminated overburden aquifer that escaped removal
from the ground water interception system and the
ground water dewatering system..
A pre-design investigation will be undertaken utilizing
techniques such as pump tests, additional drilling, tracer and
dye studies, and surficial and borehole geophysical techniques,
correlated with previous studies, to determine the hydraulic
regime in the areas of ground water recovery. The design of each
component will take advantage of this program to devise a ground
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PAGE 52
water recovery system that recovers contaminated ground water in
an efficient manner, maximizing the removal of contaminated
ground water, yet optimized to permit the functioning of any
presently operating natural attenuation mechanisms. .
Depending on the results of the pre-design investigation, the
ground water interception system could be implemented with either
trenches or wells or a combination of both. The optimum
configuration for the extraction system depends on the
.orientation of the contaminant plume at the time of
implementation, and physical constraints that may be imposed by
that orientation. These physical constraints include depth to
-ground water, depth to the aquitard, total depth of the.
extraction system, local hydraulic conductivity, and the need to
minimize surface disturbance to residents during installation and
operation.
Based on the data collected during the remedial investigation,
the ground water interception system will include collection
trenches or lines of wells, on either side of the surface water
and ground water drainag€ divide. Each collection trench or well
line will be designed to capture ground water in the upper
overburden. Each trench or line of wells will extend
approximately 350 feet, the trenches will be a maximum of three
feet wide, and the trenches or wells will be an average of
fifteen to twenty feet deep. Figure 19 on page 95 shows the
proposed ground water interception system location. The ground
water interception system for the overburden will be designed to
intercept the plu~e in the upper, more permeable till layer and
will be designed to rest on, or key into the lower, less
permeable till. By lowering the hydraulic head in the upper
till, the trench will reduce any movement of ground water through
the lower till, and hence will reduce movement of ground water
into the weathered bedrock. The length of the interception
system, its location, and operating method wili be subject to
design information as well as observations of monitoring of the
efficiencies of the remainder of the ground water recovery
system.
The preliminary location for the southwest trench is along
Tibbetts Road. Modifications to this arrangement may be
necessary to address the migration of the contaminant plume. For
instance, one portion of the contaminant plume is apparently
migrating to the west of the Site. To capture this plume it may
be necessary to extend a perpendicular leg of the trench, or to
-place a shallow extraction well in this area.
The preliminary location of the northeastern will minimize off-
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.PAGE 53
eliminated, should the weathered bedrock extraction wells drilled
in this area drawdown the overburden aquifer sufficiently, or if
elements of the ground water dewatering system and the vacuum
extraction system are sufficient to arrest overburden plume
migration in this area.
If trenching is necessary, the trench design will use as much of
the excavated material as possible for backfill. The design will
incorporate synthetic materials in the form of filter fabric and
drainage nets or similar materials vertically sandwiched to carry
flow downward to a slotted polyvinyl chloride (PVC). collection
pipe at the bottom of the trench, laid with sufficient slope to
induce gravity flow into a sump. The water will then be pumped
to the on-site treatment unit. The design or operational removal
rate from the extraction trenches and\or extraction wells is
anticipated to be approximately three gpm from the overburden
aquifer depending upon seasonal recharge.
Vacuum extraction in the overburden aquifer on-site will require
a ground water dewatering system. The depth of the water table
from the surface varies widely. During periods of high recharge
the water table is close to, or at the ground surface, while
during periods of low recharge the water table is as deep as ten
feet from the surface. This ground water dewatering system will
also recover highly contaminated ground water from the overburden
aquifer, and may be used simply as a ground water recovery system
when vacuum extraction is not being utilized. Dewatering will
occur through either wells or trenches and will potentially
extend to the bottom of the upper overburden aquifer, a depth up
to about fifteen to twenty feet over most of the Site.
Vacuum extraction will be employed on those portions of the
overburden aquifer on-site, depicted in Figure 19 on page 95,
where the concentration of total VOCs is greater than 10,000
parts per billion and the presence of NAPLs is possible. Vacuum
extraction will use ground water recovery wells or trenches to
dewater the upper twenty feet of the aquifer, then separate wells
or trenches will be used to apply a vacuum to the dewatered
overburden soils. This vacuum will cause VOCs and some SVOCs to
evaporate and migrate rapidly to the vacuum devices. This vacuum
may also enhance the recovery of contaminated ground water.
Using vacuum extraction, the length of time required to remove
the VOCs will be less in comparison to simply recovering the
contaminated ground water. This is because lowering the pressure
(with the vacuum) will increase ground water recovery and the
vacuum will cause VOCs to volatilize and move in the air to the
vacuum recovery wells. Air is much more permeable than water
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PAGE 54
volatile organic contaminants. Vacuum extraction will also
enhance the process of cleaning up NAPLs at this Site.
The construction of the ground water dewatering system for vacuum
extraction will be similar to the ground water extraction.
trenches and wells, except additional wells or collection lines
will be positioned to supply air and to apply a vacuum. Removal
of the house at the Site and covering the dug cellar with clean
soil and an impermeable liner may be necessary to minimize short
circuiting of the vacuum extraction system. Extensive regrading
of the Site may be necessary to discourage infiltration of .
surface water in some areas, or if an impermeable membrane is
necessary to perform vacuum extraction. Piloting of the vacuum
extraction system will be necessary to determine the optimum air
flow rates and if modifications to the vacuum extraction system
or the ground water dewatering system are necessary. .
After completion of operations, soil in the former source areas
will be. regraded to provide positive drainage. The'Site will
then be vegetated to limit erosion.
The ground water recovery well system in the weathered bedrock
will have wells drilled into the fractured, weathered bedrock and
will be designed to withdraw the contaminated ground water from
the fractured rock, as well as capture any contamination moving
from the till through the weathered/fractured bedrock and into
the more competent bedrock. The plan shown in Figure 19 on page
95 depicts five wells to be drilled into the weathered rock on,
and just to the north of the Site. It is expected that the
number and location of recovery wells will change once the design
investigation is complete.
All recovered contaminated media, ground water from the ground
water recovery system, and air from the vacuum extraction system
will be routed to a treatment building. This treatment building
will be capable of containing any spills inside the treatment
building, sound-proofed, and consistent in design with a rural
residential neighborhood. .
Recovered contaminated ground water will be treated in two-
stages. The first stage is metals precipitation and removal
through the addition of chemical agents. and physical processes.
In metals removal chemical additives, such as sodium hydroxide
and an anionic polymer, and physical processes will remove
dissolved and particulate arsenic, manganese, iron, and other
metals. The specific chemical additives and physical processes
will be determined during the design phase through the
performance of bench-scale studies on ground water from the
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PAGE 55
ground water in a mixing tank. By reaction, the precipitants
will convert dissolved metals to insoluble forms.. A gravity
settler will then allow the precipitated metals to flocculate and
drop out of solution, forming a solids sludge. The treated water
will be filtered, and then neutralized using sulfuric acid prior
to UV-oxidation treatment. Each tank will require some form of
VOC emissions control such as tank covers with vents and carbon
canisters for air treatment.
Sludge resulting from metals removal will be pumped to a small
filter press or similar device for dewatering. The liquid
portion will be returned to the equalization tank and mixed with
raw ground water. The sludge cake, which will be drummed and
tested, may be classified as a RCRAhazardous waste, and if so,
will have to be disposed of at a licensed off-site hazardous
waste TSD facility.
The second stage is destruction of VOCs and SVOCs through photo-
catalyzed oxidation (UV-oxidation). After metals removal the
gro~nd water will be further treated to enhance the efficiency of
the VOC and SVOC treatment process, UV-oxidation. The UV-
oxidation process will destroy organics. Available UV-oxidation
systems use either hydrogen peroxide (H202), or ozone (03), or
both. H202 and/or 03 by themselves will oxidize organics, but the
rate of oxidation is greatly increased by the use of ultraviolet
(UV) light in conjunction with these oxidants. UV light enhances
the oxidation process by transforming H202 and/or 03 into hydroxyl
radicals, which are more powerful oxidants than H202 or 03 alone.
UV light also excites organic molecules to higher, less-stable
energy levels, making them more susceptible to oxidation.
If the oxidation reaction is carried to completion, the end
products from oxidation of non-chlorinated hydrocarbons are
carbon dioxide and water. Oxidation of chlorinated hydrocarbons
may also produce hydrochloric acid and/or nonhazardous inorganic
chlorides. If the oxidation reaction is not carried to
completion, then low levels of organic compounds may remain.
Compounds that are harder to destroy will require more residence.
time in the oxidation chamber. The treated water will be further
treatsd, if necessary prior to discharge. This treatment may
include adjustment of pH and perhaps carbon absorption if the
UV/oxidation process fails to reduce any contaminant to cleanup
levels. The UV-Oxidation system will be pilot tested at the Site
prior to full operation. .
Systems using ozone typically leave residual ozone in the
effluent from the oxidation ch~mber. Since uncontrolled release
of ozone is unacceptable, ozone systems require a decomposer,
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PAGE 56
oxygen. The decomposer is vented to the atmosphere. The treated
water from the UV-oxidation unit will be monitored for compliance
with cleanup levels prior to discharge.
An additional treatment process at the Site will treat VOC and
SVOC contaminated air from the vacuum extraction system. After
recovery in the vacuum extraction system, a vacuum pump will
transfer the soil gas containing VOCs and SVOCs through a
moisture trap, installed at the suction of the vacuum pump, and
discharge to ambient air through emission controls. The air
stream will be discharged through vessels containing granular
activated carbon beds, and air discharge requirements will be
meet. The carbon beds will adsorb the VOCs and SVOCs in the soil
gas, and the treated air will be discharged to the atmosphere.
, The carbon beds will be sent off-site for regeneration or
disposal. Contaminated ground water extracted from the dual
purpose wells and the moisture trap on the air-stream will be
pumped through the ground water treatment system.
_. Figure 20 on page 96 provides a conceptual flow chart of the
ground water treatment process.
Treated ground water from the treatment system will be discharged
into the bedrock aquifer and, on a seasonal basis, into the
overburden aquifer. The injection well(s) will be drilled into
the overburden, weathered bedrock, or competent bedrock.
Discharge into any such wells will'be dependent upon hydraulic
conditions and specific conditions in the overburden and bedrock
aquifers. Discharge will be directed to portions of the
appropriate aquifer to facilitate the recovery of contaminants,
to control contaminant migration, or will simply be for the
disposal of treated ground water. The injection of the treated
ground water will serve a number of purposes:
.
provide a hydraulic barrier to the further migration of
contaminated ground water'into and through the bedrock
aquifer;
.
enhance the recovery of contaminated ground water;
.
flush contaminants in the weathered bedrock to
extraction wells; and
.
hydraulically isolate the competent bedrock from the
vertical migration of contaminants from the overburden
aquifer.
It is expected that the primary discharge will be by injection
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recharge into the overburden aquifer, it may be necessary to
direct a small amount of the treated water into overburden
injection wells or recharge beds to facilitate the collection of
contaminants. Recharge into the competent bedrock may occur in
some instances where the quantity of treated ground water exceeds
the capacity of the overburden and weathered bedrock aquifers to
absorb the flow. Such discharge will protect the bedrock from
the vertical migration of contaminants; however, it will
primarily be used to dispose of treated water. The location for
these injection wells will be developed during the design
process.
Different contaminants will be reduced to concentrations
protective of human health and the environment at different
rates. Appendix B of the Feasibility Study calculated cleanup
times for all of the alternatives, focusing on the three major
contaminants at the Site; trichloroethylene, benzene, and
arsenic. The most persistent and long-lived of the Site
contaminants is trichloroethylene. Flushing calculations found
that cleanup le.vels for trichloroethylene will be reached in
approximately twenty years in the on-site overburden materials.
In the overburden, northeast of the Site, cleanup levels will be
reached in approximately fifteen years; and in the overburden to
the southwest of the Site cleanup levels will be reached in less
than ten years.
It is important to note that these time periods were estimated on
a very conservative basis; they do not account for several
factors that will likely result in an even shorter time frame for
cleanup, such as the effects of the vacuum extraction system, the
natural attenuation mechanisms present at the Site, or the
influence of injecting treated ground water. Using the flushing
calculations similar to the overburden aquifer, the cleanup time
for the weathered bedrock is calculated to be less than fifteen
years. Again, this is a conservative estimate, as the flushing
program cannot account for natural attenuation mechanisms that
occur, and it does not consider the additional flushing effects
of the bedrock well injection. EPA expects that the competent
bedrock will reach cleanup levels well within the twenty year
time frame, perhaps in six years or less once the migration of
contaminants ceases from the overburden and weathered bedrock.
This remedy does not actively recover contaminants within the
competent bedrock. Based on current information for the
competent bedrock, contaminant levels are apparently low and
natural attenuation will reduc€ contaminant levels to below
cleanup levels during the life of the remedy as .outlined on page
29. Also, additional hydraulic containment, through injection of
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
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PAGE 58
bedrock aquifer from subsequent contamination. This hydraulic
containment will be through the discharge of treated ground water
and the elimination of pumping stresses on the aquifer by adding
ground water users to the present water supply system.
To the extent required by law, EPA will review the Site at least
once every five. years after the initiation of remedial action at
the Site if any hazardous substances, pollutants or contaminants
remain at the Site to as~ure that the remedial action continues
to protect human health and the environment19.
XI.
STATt1'rORY DETERMINATIONS
The remedial action selected for implementation at the Tibbetts
Road Site is consistent with CERCLA and, to the extent
practicable, the NCP. The selected remedy is protective of human
health and the environment, attainsARARs, and is cost effective.
The selected remedy also satisfies the statutory preference for
treatment which permanently and significantly reduces the
mobility, toxicity or volume of hazardous substances as a
principal element. Additionally, the selected remedy utilizes
alternate treatment technologies or resource recovery'
technologies to the maximum extent practicable.
A. The Selected Remedy is Protective of Human Health and
the Environment
The remedy at this Site will permanently reduce the risks posed
to human health and the environment by eliminating, reducing or
controlling exposures to human and environmental receptors
through treatment, engineering controls, and institutional
controls; more specifically, the remedy will recover and treat
contaminated ground water to levels protective of human health
and the environment and will return the ground water to a usable
condition within a reasonable time frame.
Moreover, the selected remedy will achieve potential human health
risk levels that attain the 10~ to 10-6 incremental cancer risk
range and a level protective of noncarcinogenic endpoints, and
will comply with ARARs and to-be-considered criteria. At the
time that the Interim Ground Water Cleanup Levels identified in
the ROD and newly promulgated ARARs and modified ARARs which call
into question the protectiveness of the remedy have been achieved
and have not been exceeded for a period of three consecutive
years, a risk assessment shall be performed on the residual
ground water contamination to. determine whether the remedial
action is protective. This risk assessment of the residual
ground water contamination shall follow EPA procedures and will
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posed by the ingestion of ground water. If, after review of the
risk assessment, the remedial action is not determined to be
protective by EPA, the remedial action shall continue until
protective levels are achieved and have not been exceeded for a
period of three consecutive years, or until the remedy is
otherwise deemed protective. These protective residual levels
shall constitute the final cleanup levels for this Record of
Decision and shall be considered performance standards for any
remedial action.
B. The Selected Remedy Attains ARARs
This remedy will attain all applicable or relevant and
appropriate federal and state requirements that relate to the
Site. All ARARs for the Site are listed in tabular form in
Appendix C of this document which begins on page 122. The more
significant ARARs are also discussed below.
CHEMICAL SPECIFIC
Safe Drinkinq Water Act Maximum Contaminant Levels (MCLs).
These are standards for metals, pesticides, VOCs,
radionuclides, and other classes of contaminants. These
have been adopted as enforceable standards for public
drinking water systems (40 CFR ~~ 141.11 - 141.16). MCLs
for non-carcinogens are based in part on the allowable
lifetime exposure to the contaminant for a seventy kilogram
(154 pound) adult who is presumed to consume two liters of
water per day.. The basic jurisdictional prerequisite for
MCLs is that they apply to "public water systems," defined
as systems for the provision of piped water for human.
consumption with at. least fifteen service connections.
Although not directly applicable to activities at the Site,
the potential exists for residential drinking water use of
ground water at the Site. Therefore, these standards are
considered to be relevant and appropriate.
To attain this requirement, ground water at and beyond the
Site will attain MCLs at the completion of the remedy.
These levels will be attained by the capture and treatment
of ground water contaminated with organic and inorganic
compounds in the overburden and bedrock aquifers. In the
overburden aquifer MCLs will be attained in approximately
twenty years, and in less than fifteen years in the
weathered bedrock aquifer. .
Based on current knowledge, EPA expects that contaminant
levels in the competent bedrock will attain MCLs well within
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Although no active recovery of contaminated ground water
will occur in the competent portion of the bedrock, a number
of actions will enable natural attenuation to achieve MCLs
in this time frame. The first action will be the removal of
the source, which will occur when active ground water
recovery begins recovery of highly contaminated ground water
in the overburden and weathered bedrock aquifers. The
second action will be when treated water is injected into
the weathered bedrock aquifer, enhancing hydraulic
containment, and recovery of contaminated weathered bedrock
ground water. Injection is also expected to increase
dispersion of the contaminants in the competent bedrock.
Natural attenuation of the contaminants will attain MCLs.
Only two contaminants exceed MCLs, TCE and benzene, and
those concentrations are low and diminishing, as outlined on
page 29.
With respect to lead, EPA recently promulgated lead
treatment methods, not an MCL, in the Final National Primary
Drinking Water Standards for lead. This relevant and
appropriate regulation establishes treatment techniques to
be used when an action level of 15 ppb of lead is exceeded
at ten percent of the taps sampled. The 15 ppb level is not
a mandated cleanup level; it is a level at which certain
actions are to be taken. At this Site, because of concerns
about sampling methodology and whether the lead detected is
related to contamination from the site, it will be necessary
to conduct further sampling to determine the correct
concentration of lead at the Site. Unless the data
collected during the remedial design indicate that lead is
either not associated with the Site, or that the present
samples are not representative of true ground water
conditions, the selected remedy will attain a cleanup level
of 15 ppb, in compliance with the NPDWR.
. .
SDWA MCL Goals (MCLGs) are non-enforceable health goals for
public water systems. EPA has promulgated MCLGs for nine
contaminants (40 CFR SS141.50 - 141.51) and has proposed
MCLGs for forty others (50 FR 46936). MCLGs for substances
considered to be probable human carcinogens are set at the
zero level, and MCLGs for substances that are not probable
human carcinogens are set based upon chronic toxicity or
other data. Non-zero MCLGs are relevant and appropriate
standards at this Site.
At the completion of the remedy ground water at and beyond
the Site will attain non-zero MCLGsfor those substances
which have no MCL. These levels will be obtained by the
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overburden and bedrock aquifer. The time to achieve these
goals is approximately twenty years in the overburden
aquifer and fifteen in the bedrock aquifer.
Water Qualitv Criteria Water quality criteria relating to
surface water are 'non-enforceable guidance developed under
the Clean Water Act (CWA) ~304. They are used by the State
of New Hampshire, in conjunction with a designated use for a
stream segment, to establish water quality standards. The
appropriateness of the WQC guidelines are dependent on site-
specific circumstances. Since no surface water bodies exist
near the Site except under conditions of a high water table,
these guidelines are not relevant and appropriate. However,
because under certain high water table conditions surface
water bodies may exist, the AWQC are to-be-considered in the
design and implementation of the remedy. .
New Hampshire Requlations The State of New Hampshire has
established ground water quality criteria, MCLs and MCLGs,'
pursuant to the New Hampshire W.ater Pollution Control Law
N.H. Rev. Statute Ann. ~ 485-A, in Administrative Code Part
Env-Ws 315 - 318, Protection of Ground Water. Although not
directly applicable to activities at the Site, the potential
exists for residential drinking water use of ground water at
the Site. Therefore, these standards are' considered to be
relevant and appropriate.
Ground water within and beyond the Site will attain State
MCLs at the completion of the remedy. These levels will be
obtained by the capture and treatment of contaminated ground
water. The cleanup time for both aquifers to reach these
concentrations is similar to that for the Federal MCLs.
New Hampshire Ground Water Protection Standards ENV-Ws 410
sets allowable limits for contaminants in ground water which
are based upon New Hampshire Division of Public Health
Services health based standards and Federal MCLs, MCLGs, and
other relevant standards. Ground water nondegradation
requirements incorporate the surface water quality standards
in ENV-Ws 432. This program is not promulgated, therefore
is not an ARAR. However, these standards are to-be-
considered in the implementation of the remedy.
A:list of all of the chemical-specific concentrations are listed
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LOCATION SPECIFIC
Since the Site and the contaminated ground water are on a
topographic high no impacts to surface waters, wetlands, or
flood plains will occur, the RCRA siting requirements under
40 CFR 264.18(b) are not applicable. Further, the remedy at.
the Site does not contain any geologic hazards or involve
any of the seismic considerations in 40 CFR 264.18(a).
Other location-specific pertinent ARARs are:
State of New Hampshire Ground Water Protection Act is
codified in N.H. RSA 485-C and contains guidelines for
facilities that operate in areas of specific ground water
classification.
EPA's Ground Water Protection Strateqy as identified in
guidance issued from the EPA Office of Groundwater
Protection, August 1984, issued guidelines for EPA decisions
affecting ground water protection and cleanup. This
guidance is to-be-considered.
To comply with this guidance ground water at and beyond the
Site must be restored to its beneficial use within a
reasonable time-frame through the capture and treatment of
contaminated ground water.
Ground Water Classification Guidelines categorize ground
water by its potential beneficial uses, considering quality,
hydrologic characteristics of the area, and use by both
human populations and the environment. This guideline is
to-be-considered and will be consulted in evaluating the
success of the remedy and the speed with which ground water
is cleaned up.
ACTION SPECIFIC
Resource Conservation and Recovery Act (RCRA) contains
provisions for the treatment, storage and disposal of RCRA
hazardous wastes. The jurisdictional prerequisites for RCRA
apply. to facilities that treat, store, or dispose of RCRA
hazardous wastes after July 1982. Contaminants at the. Site
were stored in drums that were in poor condition. Over
time, wastes leaked from those drums into the soil and
ground water beneath the Site. It is unknown if these
wastes were disposed of before July 1982, and if that waste
was similar in composition and use to a RCRA listed or
characteristic waste. However, the high concentrations of
contaminants found at the Site coupled with their apparent
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sufficiently similar to RCRA listed wastes prior to their
disposal. Therefore, portions of RCRA are relevant and
appropriate to certain components of the selected remedy.
Wastes at the Site include the ash residue of the
incinerator which treated soil contaminated with dioxin
(various isomers) similar in " composition and production to
RCRA listed wastes such as F028. However, this waste was
not a RCRA listed waste. " Futhermore, because all wastes
contained in the ash which are similar to RCRA listed wastes
have been re~uced to concentrations (below detection limits)
that pose no unacceptable risk to human health and the
environment, RCRA hazardous waste management rules are not
relevant and appropriate to the ash. The material in these
drums will be re-tested prior to off-site disposal to ensure
its protectiveness. In order to provide an extra measure of
protection, Subtitle C regulations will be considered in the
containing and storing of the wastes on-site. The
incinerator ash will then be disposed off-site at an
appropriate facility operating in compliance with Federal
and State regulations.
Three drums of granular activated carbon, used in the water
filtration treatability study, are contaminated with wastes
derived from the contaminated ground water. These
contaminants are derived from wastes similar in composition
to RCRA listed hazardous wastes FOOl, F002, F003, and FOOS.
The granular activated carbon will be disposed off-site at
an appropriate facility operating in compliance with Federal
and State regulations. RCRA subtitle C provisions for
containing and storing of these wastes on-site, prior to
off-site disposal, will be relevant and appropriate.
Ground water at the Site and migrating off-site is
contaminated by wastes similar in compQsition to RCRA listed
hazardous wastes FOOl, F002, F003, and FOOS. The original
concentrations of these contaminants and the date of their
disposal on the land are unknown. Therefore, although RCRA
is not applicable, portions of the provisions of Releases
from Solid Waste Management Units, RCRA 40 CFR ~~ 264.90
through 264.1Ql, are relevant and appropriate. A
comprehensive ground water monitoring system, designed to
detect and measure ground water contamination within "and
beyond the Site will meet the substantive standards of this
regulation.
The substantive portions of general RCRA operating
provisions are relevant and appropriate for the selected
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inspection requirements (40 CFR 264.15), personnel training
(40 CFR 264.16), and Closure and Post-Closure (Subpart G, 40
CFR 264.110 - 264.120). To comply with this ARAR, all
contaminated materials and equipment will be removed from
the Site upon the. closure of the Site, also monitoring of
ground water at and beyond the Site will be necessary after
the closure of the Site.
In addition, the following RCRA provisions are relevant and
appropriate to the component of the selected remedy calling
for storing, treating, and discharging treated ground water.
The provisions of Preparedness and Prevention (40 CFR 264.30
- 264.37), Contingency Plan and Emergency Procedures (40 CFR
264.50 - 264.56), Manifest System, Record-keeping, and'
Reporting (40 CFR 264.73), and the general requirements for
ignitable, reactive, or incompatible wastes (40 CFR 264.17)
are relevant and appropriate in the construction, operation,
and maintenance of any facility that stores and treats
contaminated ground water. The selected remedy will comply
with this ARAR through preparation of the substantive
portions of the Preparedness and Prevention requirements,
the development of a contingency plan and emergency plan,
and the manifesting, packaging and labelling of all
hazardous wastes collected.
.In addition, elements of the treatment plant will trigger
provisions of some of the RCRA requirements under 40 CFR
264.. Ground water treatment will entail the collection,
storage, and treatment of contaminated ground water.
Therefore, the collection and hydraulic containment or
contaminated ground water within the bedrock and overburden
aquifers shall be consistent with the relevant and
appropriate portions of 40 CFR 264 Subpart F, Releases from
Solid Waste Management Units. The requirements for Tank
Systems (40 CFR Subpart J), the Use and Management of
Containers (40 CFR Subpart I) "and Drip Pads (40 CFR Subpart
W) are relevant and appropriate for the components of the
treatment system that utilizes holding and equalization
tanks as well as containers for the storage of sludges. The
components of the remedy will comply with all substantive
portions of these ARARs. .
" As to any RCRA listed or characteristic wastes generated as
- sludge in any metals precipitation process or in other areas
of the treatment process, the requirements of RCRA (40 CFR
Part 264) shall be applicable.
Portions of RCRA will be relevant and appropriate to
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regulated under the provisions of Incinerators (40 CFR
Subpart 0) for air emissions treated by catalytic
converters. Air discharges from vapor phase carbon
treatment will be regulated under the provisions of Air
Emission Standards for Process Vents (40 CFR Subpart AA) .
EPA guidance on control of air emissions (OSWER Directive
9355.0-28, June 15,1989) is to-be-considered for the remedy
at the Site, which is in an ozone non-attainment area. For
such an area, the directive indicates the need for control
of VOC emission from CERCLA remedies based on actual
emission rates of VOCs.
The discharge of treated ground water on-site will be by
recharge into the overburden aquifer or well injection into
the bedrock and overburden aquifers. Such discharge is .
normally prohibited by Section 3020{a) of the Solid Waste
Disposal Act (RCRA). HQwever, Section 3020{b) of RCRA
allows for the injection of treated contaminated ground
water (a Class IV injection well under the Underground
Injection Control Program of the SDWA) into an underground
source of drinking water as part of a CERCLA response action
if (1) the injection is a CERCLA response action or a RCRA
corrective action, (2) the contaminated ground water must be
treated to substantially reduce hazardous constituents prior
to such injection, and (3) the response action or corrective
action must be sufficient to protect human health and the
environment upon completion. Any re-injection of treated
ground water into the bedrock or overburden aquifers will
meet the substantive requirements of Section 3020(b).
Land Disposal Requlations (LDRs) (40 CFR Part 268) are not
applicable or relevant and appropriate for any of the
remedial actions considered at the Site. LDRs prohibit land
disposal of restricted RCRA hazardous wastes that do not
meet treatment standards. In the context of a CERCLA
response action, the applicability of LDRs is measured by
whether the CERCLA action will result in placement of RCRA
wastes in a new area of contamination (AOC). At the Site,
the pertinent AOC is the contaminated soil.
The selected remedy contemplates that trenches may be dug at
the Site. These trenches will be dug to a depth below the
saturation point of the Site soil, i.e. into the
contaminated overburden aquifer. Thus, earth will be
removed that is saturated with contaminated water. This
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portion will remain on the surface. This excavation does
not amount to a placement of RCRA wastes because
contaminated earth remains in the pertinent AOC at all
times. It never is placed in a new, non-contaminated area.
This type of waste movement or consolidation, within an AOC,
does not result in placement.
Safe Drinkinq Water Act contains provisions for an
Underground Injection Control (UIC) program which has been
delegated to the State of New Hampshire. The requirements
for this program are outlined in 40 CFR Parts 145 and 146,
and met during anyon-site injection of treated ground water
to either the bedrock or overburden aqu~fers.
Clean Air Act (CAA) regulates emissions into the air through
National Ambient Air Quality Standards (NAAQS), National
Emission Standards for Hazardous Air Pollutants (NESHAPS),
and New Source Performance Standards (NSPS). NAAQS regulate
the emission of six "criteria pollutants" through 40 CFR
Part 50, but are not applicable to specific sources of
pollution. Instead, the State of New Hampshire has primary
responsibility for assuring that NAAQS are attained through
the development of a federally-approved State Implementation
Plan (SIP). Under the Clean Air Act, EPA established two
classes of emission standards: NESHAPS, which regulate
those emissions for which no AAQS exists but which may
contribute to increases in mortality or illness (40 CFR Part
61), and New Source Performance Standards (NSPS), which set
emission standards for major new stationary sources.
Although the remedial action does not constitute a major new
source, portions of these standards will be relevant and
appropriate to air discharges from treatment processes,
excavation associated with the ground water remedy, and the
clearing of Site debris.
NEW HAMPSHIRE REOUIREMENTS
In addition to federal ARARs, listed below are several New
Hampshire requirements which are applicable or relevant and
appropriate to potential remedial alternatives. Similar to
Federal ARARs, State of New Hampshire ARARs govern only on-
site activities, and the selected remedy must comply with
the substantive portions of these ARARs. Off-site
activities will be subject to Federal and State of New
Hampshire laws and administrative requirements.
Those State of New Hampshire regulations which are
applicable or relevant and appropriate or to be considered
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implementation of the remedy include the following:
.
New Hampshire Hazardous Waste Management Law, RSA 147-
A. This statute pertains to the treatment, storage,
transport, and disposal of hazardous wastes. This
statute is not applicable since no regulated RCRA
wastes are being treated on-site. However, for the
reasons stated above, it is relevant and appropriate to
portions of the selected remedy. In particular, after
the construction of the ground water recovery trench,
samples of the soil surface will be taken to insure
that no hazardous materials exist at the ground surface
at concentrations that are hazardous to human health
and the environment.
.
New Hampshire Hazardous Waste Rules (RSA 147-A:3)
Chapter Env-Wm 500 and 700. Standards for Generators
are contained in Env-Wm 500 and govern the testing of
materials to be transported off-site and manifesting.
These requirements are relevant and appropriate and the
remedy will meet these requirements. Env-Wm 700
contains New Hampshire's requirements for owners and
operators of hazardous waste facilities. Portions of
it are relevant and appropriate including, among other
things, closure and post-Closure requirements. The
substantive portions of these requirements will be met
by the remedy.
.
New Hampshire Ground Water Classification System, RSA
485 C. These standards establish ground water
classifications and prohibit certain uses within areas
of certain ground water classifications. The
substantive portions of these regulations will be
relevant and appropriate and the remedy will comply
with those portions.
.
Abandonment of wells, NH Code of Administrative Rules
Part Env-We 604. This regulation shall be applicable
to all wells abandoned at the Site.
.
NH Code of Administrative Rules Part Env-Ws 346 and
347, Best use of available technology for remedial
activities. This regulation requires the use of best
available technology for inorganic, organic and
organic-synthetic chemicals. This regulation is
intended for the protection of surface water. Since
the remedy will discharge to ground water this
requirement will be relevant and appropriate and the
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.
New Hampshire water pollution and waste disposal (RSA
485-A:12). Prohibits the disposal of wastes in such a
manner as will lower the quality of any surface water
below the minimum requirements of the surface water
classification. This requirement is relevant and
appropriate. The remedy will meet the substantive
portions of this requirement by limiting or eliminating
the discharge of contaminated ground water to nearby'
surface water bodies.
.
NH Administrative Code Part Env-A 300 (Primary and
Secondary Ambient Air Quality Standards), Part Env-A
800 (Testing and Monitoring Procedures), Part Env-A 900
(Owner or Operator Obligations), and Part Env-A 1300
Toxic Air Pollutants.
These regulations contain the State of New Hampshire's
SIP and other requirements. Many of these standards
apply primarily to' "major" or new sources of
pollutants, which are not directly comparable to the
CERCLA remedial action. However, substantive portions
of these regulations are relevant and appropriate to
components of the remedial action, including excavation
of soils and operation of the vacuum extraction and
groundwater treatment systems. In particular, since New
Hampshire is a non-attainment area for ozone, the
emissions from the ground water treatment 'system must
achieve the Lowest Achievable Emission Rate (LAER).
.
New Hampshire regulations for VOC emission controls, NH
Code of Administrative Rules Part Env-A 1204. This
requirement specifies VOC emission control methods and
establishes limitations on VOC emissions for various
process categories. This requirement is not
applicable, however, because the remedial action at the
Site has some similarity to those regulated processes,
however, portions of this requirement are relevant and
appropriate and will be attained.
.
Env-A 1002, Fugitive dust control. This regulation
prohibits the emission of fugitive dust as defined in
Env-A 101.42. During construction and implementation
of the remedy precautions must be taken to prevent,
abate and control fugitive dust emissions. This
requirement will be relevant and appropriate.
Env-A 1305, Air quaiity impact analysis. Sources of
airborne contaminants must perform air quality impact
analyses in accordance with the NHARD Policy and
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Procedure for Air Quality Impact Modeling or other
comparable dispersion modeling methods approved by
USEPA. This requirement is relevant and appropriate.
C. The Selected Remedial Action is Cost-Effective
In the Agency's judgment, the selected remedy is cost effective,
i.e., the remedy affords overall effectiveness proportional to
its costs. In selecting this remedy, once EPA identified
alternatives that are protective of human health and the
environment and that attain, or, as appropriate, waiveARARs, EPA
evaluated the overall effectiveness of each alternative by
assessing the relevant three criteria--long term effectiveness
and permanence; reduction in toxicity, mobility, and volume
through treatment; and short term effectiveness, in combination.
The relationship of the overall effectiveness of this remedial
alternative was determined to be proportional to its costs. The
costs of this remedial alternative are:
Alternative Capital
MM-l, No action -0-
MM-2, Limited action $383,400
MM-5, pump & treat $2,228,190
MM-6, pump & treat $1,897,060
MM-7, pump & treat $1,728,690
Operation and
Maintenance
-0-
$642,500
$2,169,500
$2,769,070
$2,046,970
Present Worth
-0-
$1,025,900
$4,397,690
$4,666,130
$3,775,660
The selected alternative, MM-7, is the least expensive of those
alternatives that actively recovers and treats contaminated
ground water. The'primary cost savings are the use of an on-site
bedrock injection well and the operating efficiency of the UV-
oxidation treatment system. With the UV-oxidation treatment for
ground water contaminated with VOCs and SVOCs there is minimal
need, if any, for carbon treatment of any of the effluent, liquid
or alr. ' '
There are significant differences in cost as noted in previous
sections that detail each alternative. While MM-1 has no capital
or operation and maintenance cost, MM-2 will cost about one
million dollars, MM-5 and MM-6 over four million dollars, and
MM-7 somewhat under four million dollars. The capital, operation
and 'maintenance, and total cost for each alternative is provided
as part of the description for each alternative in the preceding
sections.
The selected alternative, MM-7, is more cost-effective than the
no-action (MM-1) or limited action (MM-2) alternatives. MM-7
will result in the restoration of ground water in less than half
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overburden aquifer on-site -- less than twenty years as opposed
to forty years or more. In the competent bedrock, ground water
will be restored in perhaps less than a quarter of the time (six
years vs. forty years or more) at an appropriate, incrementally
larger cost than a no-action or limited action alternative. As
stated above, the vacuum extraction component enhances the
certainty of attaining cleanup in a reasonable time frame than
the MM-1 or MM-2 alternatives. Given that EPA policy as stated
in the National Contingency Plan favors rapid restoration of
groundwater, the incremental cost of MM-7 is proportional to the
benefits of rapid restoration. .
The selected alternative, MM-7, and the other active
alternatives, MM-S and MM-6, are cost effective over alternatives
MM-1 and MM-2 in that they halt migration of contaminants and
return the aquifer to a usable condition in at least half the
time required for natural attenuation. Alternatives MM-1 and MM-
2 would necessitate additional years of operation of the water
supply system and perhaps the addition of more users whose wells
become contaminated by the Site.
The selected alternative is cost effective over the other active
remedies, MM-5 and MM-6, in that it is not only the least
expensive but also destroys the organic contaminants on-site,
unlike MM-6, and does not necessitate acquiring access to
property to discharge treated water as does MM-S.
D. The Selected Remedy Utilizes Permanent Solutions and
~ternative Treatment or Resource Recovery Technologies
to the Maximum Extent Practicable
Once the Agency identified those alternatives that attain or, as
appropriate, waive ARARs and that are protective of human health
and the environment, EPA identified which alternative utilizes
permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable.
This determination was made by deciding which one of the
identified alternatives provides the best balance of trade-offs
among alternatives in terms of: 1) long-term effectiveness and
permanence; 2) reduction of toxicity, mobility or volume through
treatment; 3) short-term effectiveness; 4)implementability; and
5) cost. The balancing test emphasized long-term effectiveness
and permanence and the reduction of toxicity, mobility and volume
through treatment; and considered the preference for treatment as
a principal element, the bias against off-site land disposal of
untreated waste, and community and state acceptance. The selected
remedy provides the best balance of trade-offs among the
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Except for the No Action alternative, all of the alternatives
presented in this Record of Decision would provide overall
protection of human health and the environment. In EPA's
analysis, however, alternative MM-7 is more readily implementable
than, and comparable in. cost to, the other alternatives
considered. In addition alternative MM-7 will achieve the best
balance among the criteria used by EPA to evaluate the
alternatives. Alternative MM-7 will provide short- and long-term
protection of human health and the environment, will attain all
Federal and State applicable or relevant and appropriate public
health and environmental requirements (ARARs), will reduce the
mobility and toxicity of contaminated ground water and will
utilize permanent solutions to the maximum extent practicable.
Alternative MM-7 is protective of human health and the
environment and will also attain chemical specific ARARs in a
significantly shorter time period than alternatives MM-1 and MM-
2. Alternative MM-7 will also be effective over the long term
and permanent because the contaminants will be removed from the
environment.
Alternative MM-7 will effectively reduce the toxicity, mobility
and volume of contaminants through treatment to a greater degree
than all other alternatives. Metal contaminants at the Site will
be immobilized for off-site disposal reducing the mobility of
those contaminants as well as the volume of metal-contaminated
ground water. Organic contaminants at the Site, VOCs and SVOCs,
will be destroyed at the Site, reducing toxicity, mobility and
volume of the organic contaminants. The discharge of treated
ground water. into the bedrock and overburden aquifers in
alternative MM-7 will reduce the mobility of both organic and
metallic contaminants and enhance the recovery of those
contaminants. .
Alternative MM-7 poses the same short-term hazards as
alternatives MM-S and MM-6 with respect to the construction
phase. Alternative MM-7 would create some emissions to the
atmosphere with the catalytic air treatment system and the vacuum
extraction air treatment system; however, any such emissions
would comply with ARARs.
Alternative MM-7, in comparison to MM-5 and MM-6 will be the
easiest alternative to implement, because most of the remedial
components are on-site. Therefore, the administrative
requirements will be lessened. Alternative MM-7 also proved to
be less costly than alternatives MM-5 and MM-6 because of the
treatment type and discharge option. The discharge options in
MM-5 and MM-6 would require easements and substantial
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 72
The No Action (MM-1) and Limited Action (MM-2) alternatives were
not selected because they were ineffective in reducing
contaminant toxicity, mobility, or volume of contaminants; and
did not provide a permanent and long-term remedy. Alternatives
MM-1 or MM-2 would not be protective of human health and the
environment.
Alternative MM-7, as well as MM-2, MM-5, and MM-6, will provide
overall protection of human health and the environment. However,
the alternative MM-7 is more readily implementable than and
comparable in cost to the other alternatives considered except
MM-2. Alternative MM-7 will achieve the best balance among the
crit~ria used by EPA to evaluate the alternatives. Alternative
MM-7 will provide short- and long-term protection of human health
and the environment, will attain all Federal and State applicable
or relevant and appropriate public health and environmental
requirements (ARARs), will reduce the mobility and toxicity of
contaminated ground water within a reasonable time-frame, and
will utilize permanent solutions to the maximum extent
practicable.
B. The Selected Remedy Satisfies the Preference for
Treatment Which Permanently and Significantly reduces
the Toxicity, MObility or Volume of the Hazardous
Substances as a Principal Element
The principal element of the selected remedy is the management of
migration. This element addresses the primary threat at the
Site, contaminatiQn of ground water. . The selected remedy
satisfies the statutory preference for treatment as a principal
element by capturing and treating contaminated ground water to
remove inorganic contaminants and to destroy organic
contaminants.
XII.
DOCUMENTATION OF NO SIGNIFICANT CHANGES
EPA presented a proposed plan (preferred alternative) for
remediation of the Site on June 24, 1992. The remedy selected in
this Record of Decision is the same as the preferred alternative.
The management of migration portion of the preferred alternative
inc~uded: .
.
upgrading and improvement of the existing drinking
water distribution system;
.
capture of contaminated ground water in the overburden
and bedrock aquifers through the use of trenches and
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 73
.
removal of inorganic (metallic) contaminants from
ground water through chemical flocculation,
sedimentation and filtration; .
.
destruction of organic contaminants from ground water
through ultra-violet catalyzed oxidation (UV-
Oxidation);
.
capture of highly contaminated ground water and soil-
gas through the use of dewatering and vacuum extraction
on-site, the air stream will be treated with carbon
absorption, the recovered ground water will be treated
in the afore-mentioned ground water treatment process;
and .'
.
discharge of treated ground water into the overburden
and bedrock aquifers to effect containment and enhance
ground water recovery and cleanup.
XIII.
STA'l'B ROLE
The New Hampshire Department of Environmental Services has
reviewed the various alternatives and has indicated its support
for the selected remedy. The State has also reviewed'the
Remedial Investigation, Risk Assessment and Feasibility Study to
determine if the selected remedy is in compliance with applicable
or relevant and appropriate State Environmental laws and
regulations. The State of New Hampshire concurs with the
selected remedy for the Tibbetts Road Site. A copy of the
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 74
ENDNOTES
1. U.S. Geological Survey; 7.5' x 7.5' Barrington Quadrangle
topographic map; Scale 1:24,000; Vertical datum 1929, edited
1981.
2. Personal communication between Stan Swier and Norman
Boucher, Swains Lake Village Water District to Darryl Luce,
USEPA, June 1992.
3. Action Memorandum from Michael Deland, EPA Region I, to Lee
M. Thomas, EPA Headquarters (April 6, 1984). Concerning
justification for authorizing an immediate removal action, with
attached: "CERCLA Fund Authorization Immediate Removal Action
Tibbetts Road Drum Site, Barrington, New Hampshire."
4. Action Memorandum from Michael Deland, EPA Region I, to Dr.
J. Winston Porter, EPA Headquarters (July 18, 1986). Concerning
the disposition of dioxin and PCB contaminated soils and the need
for an alternate water supply system.
5.
Shirco Incinerator
6.
April 17, 1984 letter to EPA Public Health Advisor
7. HYdroqeoloqical Site Study, Tibbetts Road Site, Barrinqton,
New Hampshire. Hydrogeological Investigation Unit, New Hampshire
Water Supply and Pollution Control Commission, Report #144.
January 1985. "
8. GeohYdroloqical Investiqations, Tibbetts Road
Barrinqton. New Hampshire. Environmental Response
and Environmental Emergency Response Unit (EERU).
1986.
Site,
Branch (ERB)
February 5,
9. Action Memorandum from Katherine Daly, EPA Region I, to
Michael Deland, EPA Region I. Approved by Paul Keough (September
12, 1985). Concerning an immediate removal request for
continuation of removal activities and provision of a supply of"
drinking water. "
10. United States of America v. Ford Motor Company Case # ,
filed in United States District Court, District of New Hampshire,
March 28, 1992.
11. A Guide to Principle Threat and Low Level Threat Wastes,
Superfund Publication 9380.3-06FS, Office of Emergency and
-------
T'IBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 75
12. Results of Analvsis for Dioxins/Furans, Tibbetts Road Site,
Barrington, New Hampshire. Katherine E. Daly, On-scene
Coordinator. January 16, 1986. (Earlier references summarized
and appended) . .
13. Element
Materials of
Survey Paper
Boerngen.
Concentrations in Soils and Other Surficial
the Conterminous United States: U.s. Geological
1270, 1984. Hansford Shacklette and Josephine
14. Final Report, Sampling and Analysis Program, Shirco Portable
Pilot Unit, February 1987 (pp. 48 & 49).
15. Personal communication between
Allain (Engineer for Mrs. Saulnier)
between Darryl Luce and Mr. Stanley
1992.
Darryl Luce (USEPA) and David
on November 22, 1991; and
Swier (resident) on July 14,
16. Long, E.R., and L.G. Morgan. 1990. The Potential for
Biological Effects of Sediment-Sorbed Contaminants Tested in the
National Status and Trends Program. NOAA Technical Memorandum
NOS OMA 52. Seattle, Washington.
17.
Ground Water Flushing Model.
Camp, Dresser, and McKee.
18. Memo from Katherine E. Daly, OSC to Taylor Treat, O.H~
Materials regarding sample results of analysis of drums, August
27,1987.
19. Memo from Henry Longest regarding planning and conducting
-------
APPENDIX A
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION ~ SEPTEMBER 29, 1992
PAGE 77
coos co.
~
NEW HAMPSHIRE
NO SCA1.E
T1BBETTS ROAD SITE
IWIAINGTCN. HaW IWWSHIA£
GENERAL LOCA TtON MAP
-------
TI33ETTS ROAD SUPERFUND SITE, BPRRINGTON, NEW K&~PSHlRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 78
SOURCE: USGS BARRINGTON.H.H.
OUACRANGI.E 1981
CONTOUR INTERVAL; 10 feET
FIG.
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE 79
H.., 2' ~. ,.."hU
Drum 510"9' Are..
- r.... li.. R..lricled Area
P"pert, S...dari.. IApprOliroato fram
101 lop.' labll.d b, OlOer
Figure 3
SITE !utUUS AND SUIIOUUI"' AliA
TIBBETTS ROAD. BARRINCTON. NH
SUi. ,: I,UO It.
III
:u lu'
l:r.::. ':,'.::rl [r::rl h,."....u. ItI. II. III'
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 80
&
'31\
~
.
I
,.
. S3S
I
K
iii
,,"
';01
- Croll Seeliu
Figure 4
LOCATIONS Of CIOU.IICTIONS
A.A', 1.1' AND C.C'
TIBBETTS ROAD. BARRINGTON. NH
"11, I: I,UO 1;;-
'01
:..,...
-..-...... .-..
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE
81
.VOTE: GROlJ1'<"DW A TER ELEV A nONS SHOWN WERE MEASURED 7/5/91
SiR YS
acs SSS
, ,
71sam
&IoSE!P
, 78A
3SI
,co
200
]CO
...
500
iC;)
700
...
...
I,'"
, -
(Of?Sc"'j35'W'I~;
I r1.vArD.aI...j
"I jI9:5
HALL. ROAD---j /
A'
A
/-
i ;(O"SET ~5"W\
r.!! BE"!'TI ROAD S!TE
325
BROWN SA.''Dy ~
~ (OFFSET G' WI
-...,..,.
A."'CCJ.AUILT
"-"tDFt:ooltSA."CD
ih-
~
Z3DO
~
Z
;a
:;c
>
"im
5:j
..
VE!l.YDENSE
CiltAy'IIU. ,.:
:.,
:-,".-...
FRACI'tJREI)
BEDROCX
IMICASCIIS'O
2!!0
COMP!!'l"E:'o"T
BEDROCK
(QUAJm: 1oIO/IZONrn)
INFERRED
BEDROCK
CONTACT
(ditI-"'1
CO~"T
BEDRQOC
(QUARTZ MONZONrn)
ZZ5
200
"'"
1".5
BOTTC"~ --.-
a.EV.---.!.-L
sac
...
7aQ
BOO
...
I,'"
IIOnt)U B.e#,
_7 AFTSI caJ»S&
r 11L7 IIEFaIE CCIJ.N'SI!
,a, ~~
BOTTO" EI..EV. ...!-..I.-
~ 8One" E!.EV.
U:C&'ID: . O~ HOU;
. safI!.''ED I:'m!Rv AI.
TIBBEITS ROAD SITE
BARRDIGTON. NEW HAMPSHIRE
2D 10 0
SC.~ "~11!<.:Cr....- ~
HOR:Z t IN -10 FT' -
10 ..
??!
..
CROSS SECTION A-A'
FIGURE
-------
L£GE:'II>.
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE 82
NOTE: GROUNDWATER El.EV A110NS SHOWN WERE MEASURED 7/5/9 I
UNLESs NOTED OTHER WISE
3!0
~50 J~ S4S
~;'5A
500
100
~;:s
5ZS37'0 UR
..-
""
50Q
'''''''':oR. h
5UV
~:9.J'
= ~F;~~~k.E)
(OFFSET ~S" e~;!!C ".n
B
::J
~3DO
~
Z
g
<
>
~m
FIIIM
BJtOWH 4l'I'D CRA T
SIL':' AHD FtS1! So\I'fD
3~~~~EI!P -
-
-
-
-'
Z50
COMP£TENT
BEDROCIt
(QIJAlttZMIOICZIONrn;)
2ZS
::: : ""
T. 101." lIDTTCMaEV.
JOG
-
. SOD
...
'""
. OPS:-;~,:!..!
. SOl5.'"E':: :,.~....~
TIBBETTS ROAD sm
BARR~G1'OS. :.EW HAMPSHIRE
CROSS SECTION B-B'
lOll
.000
UGHrBROWN
SAN!) AM) SILTwrrH CRA vex.
I'RACTtJRE)
QUARTZ MONZONITE
BEDROCC
---
--
--
.-
SIOO
,-
1.000
~ICFFSET"'EJ
1.
B'
I
I
"'Am< I
EIJEV. ::19,"1
.. 104'90 .
-AID 1IOTTt).. EIEi.
, .
1ii'0 0
sc.u.E: VERT I IN .:!:O FT --
IIDItIZ IIN . 80 FT -
SO .. .
..,
I
FIGURE
-------
"
...
'"
Ii: :xii
~
z
9
'"'
<
>
::I Z7!
a
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECO~ OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE 83
scs
35CI
'00
:IZI
..z~ .
. .::..;. VERY DESSE
::.;-. ORA Y1:ILL
~
?
!'IK.\4
BROWN AII1>CRA'f
SILT AN'D F1NB SAJ-'D
2!C
225
'00
UtGI!ND: . Ol'!!:'l HOLE
a ;~.c!):O:;.:.il'.~
12':1.2
ecr.-c.. EL.c-V.=II
NOTE: GROUNDW A 1El £LEV A nONS SHOWN WERE MEASURED 7/5,91 I
I
3~S1S'H~
7"S ,~
~ ~cs 52S31CHA
~
72$
I-
f-
JCO .co
11BBE'!TSROAD5~
8RO~ SAl/DY-:t.I.
I~ ~'7SJ~OFFS~.~~SETIC'SJ
i~~ ~ ::;: ~:OFFSET~
700
...
%00
...
COMPETE.."IT
BEDROCK
%00
:100
500
-
....
...
700
r-115.~ BQ1'1't)Ma£Y.
,
TIBBETIS ROAD SITE
BARRJNGTON. NEW HAMPSHIRE
1IRm
. goo
'.-
C'
W!!A '!IIERED
IIOC%
-
...-
goo
,-
r111.a 1CmDUQ.EV.
~
SCALE: YEItT II!I . 2D PT
HCJUZ t ~ .8)Pr
80 ... .
CROSS SECTION C-C'
FIGURE
.."
I
~I
-------
TIBBETTS ROAD SUPERFUND SITE, B~_~INGTON,
RECORD OF DECISION - SEPTEMBER 291 1992
NEW HAMPSHIRE
PAGE
84
~
..1:
WATER
TREATMENT
PLANT
.-
.-
WATER
JNT AKE
LOCATION
SWAINS ~)..<::
.~,
.. aoo.8d 1rrco 1MC8r 8UOP&" ."~-
. On.CUIdby ~c1y \l8U1q O'INIteN~.. ....u
!
TIBBETTS ROAD SITE
BARRINGTON. NEW HAIoIPSHIRE
FEET
SCALE
o Oft 8cand1ry ca.nwrcJ. Y Ul.nq D8droct -n
o IIoCo Oft 8Y'8C_. \aNI:naIwIa ~ 3t .....1.1
PUBLIC WATER SUPPLY SYSTEM
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE
85
~//
~
.
.
.
I
d's-us.
,,'-£20. aI"-£2..
d'N200
. .3-.JOQ
,112-[250
.
~
K
~
o
X
tOC 1I..,li., huti.. (1115)
woe St.,li_. huti.. liItO)
All a ..1.10 1I..,Ii., L.uti.. (1110)
,..hClh 1: pea S..,li., hetlie. (IUO)
--
SUi, ,. 110 sa .
rlt"
Sit. ",'i., Sill
Dru. .
Slor'g. ArlO
figure 9
SOil SliD SAIIPlI.S LOCAtiO"
Iltll)
TIBBETTS ROAD. BARRINCTON. NH
II
1111,,1
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SE?TEM3ER 29, 1992
PAGE 86
1,059 0
""-- ~
FEET
SCALE .. I: 12.701
1'IBBETI'S ROAD srI'E
BARRINGTON, NEW HAMPSHIRE
SCAU: I" - 1059 ft..
SURFACE WATER AND SEDIMENT SAMPLE LOCATIONS
January 18, 1991 and June 29, 1991
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 87
/
f...." toJ>L.
1-"'" .1".li.. 111 rtJ
~-
\
.'f
-,.11 I ;ro.nd 'GI., SGlllplin, lGCGtiu
figurell
MONITOIING WELL LOCATIONS
,,"1.'11
TIBBETTS ROAD, BARRINCTON, NH
s c ,Ie I
: 1.1IG
1" , ,.. 211 "1'
h,," hll ..,: r...." r.,.t'.,..". h.. u. 1111
,;
)
(V~
-------
TIBBETTS ROAD SUPERFUND SITE, B&qRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE 88
~..~
.1:1(;.. 'tD
"
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.
l
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.
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8M . ..,....., oca . GCa81' "'J.8Ul. ~a.c ~
o It II I "".d hit( S...,fi., l.uti..
ALL CONCENTRATIONS IN PARrs PER BILLION
lID . IIoC o.C8C'C8d
~~ ---
11: ,
If I
:.. ,,,I .
Figure 12
TOrAL VOLA1'ILE ORGANIC COHPOCNDS
IN OVERBURDEN AQtnFER
mUffS KOJD. BUR/IiCiOH, ilK
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 89
,.."'Ie
;,a
"
~..
.:::,--..
a, .,
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:.T, .:.1
.
~-:;--o
x
.
ARSENIC / LEAD (unfiltered)
~::::;~
II: I
III
201 1,,1
Figunt 1 3
CONTOUR MAP OF tJKFIL'rERED ARSENIC
IN OVE1U5tJRDEN AQUIFER
TllBEiTS 1010; BHRIHCTO!t. HH
o ',II I 'lOud ,.tll $'18,lil' ltC.li..
AI... CONCENTRATIONS IN PARTS PER BILLION
lID . IIOc Det8c:C8d
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 90
-.
.
.
.
,
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.
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... ...
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l
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o "II I '....4 lot" S,..,li., L...li..
ALL CONCENTRATIONS IN PARTS PER BILLION
lID . -.: CI8c8c:hd
te,l,
~-~
I', . 181 :" ".1
Figure 1 4
TOTAL VOLATILE ORGANIC COMPOUNDS
IN BE~ROCK AQUIFER
flaB£riS Roa. 8A~RINCian. HH
'fa . CZ'J.dUoroeca'l.... r PC8 . t.cr.c:aL02'08Gt'fh...
II8a . -..-, oat . oCA8r VoL.tU. 0l"Jua.c ~
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 91
1;-:-:;;; t. L .
.
.
,~
...
.
..
.
~~
.. .
~..
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paae
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o ..11 I "...4 ,.Ift' 5o..,li., l.coti..
ALL CONCENTRATIONS IN PARTS PER BILLION
ARSENIC / LEAD (unfil.tered)
Figure 15
CONCENTRATION DISTRZBUTION OF
ARSENIC IN BEDROCK AQUIFER
TI3Hii3 ~C~~. aUmCTQN, 11M
'uh
~-
... . ".a--:;'I,...
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 92
1...... i..L.
..
..
II
~
.
I . 83S
J(
-'
...... I
,
,
I
. ,.11 / Cr.und ..1" S.mpling l.c.li..
e:; Ar.. [,,"ding CllOnu, l".I.
in Ih Orcrbu,d.. A.ulf"
~ Ar.. [acnding Acti.. l...1 '.r
Unfiltll.d ltad in tbe Orcrburon Aquifer
Setl, I: 1.440 II~ :U UI I..,
figure 16
OV!IIUID!" CIOU"D WAf!1
CONtAIlIHATIO" flUII!
TIBBETTS ROAD. BARRINCTON. NH
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 93
..
..
3311.
11
~
..
I
K
. ihl! I Cround lohl Sompiuaq locat,on
IZ:J 4". (""din! CI..nup L...,s
in the 8edrod A4uihr
Figure 17
110100 'IOUNO WAHl
CONTAMINAIION PlUMI
TIBBETTS ROAD. DARRINCTON. ~H
Sell. I: 1,440 III
'"
ZG~ Iltl
tltrtl till ... fullu ""''''''0 J... I' !II,)
I
}1
~t-'. I
I
I
i
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER .29, 1992
NEW HAMPSHIRE
PAGE
94
~()
0&
o
()
CONTAMINANTS INCREASING
IN CONCENTRATION FROM
1985 TO 1990
1J'
.
o
'rCS ... 'rriQ~lQroeUyl.n.
PC! ... Te~=sChlQr~.~~y ':'en.
BEN ... Benzene
DC!: ... 1.l O.i.chloro8t.."1y18ne
XYt. - Xylen8s (~o~..l)
'rOt. ... Tol\.18n.
EBD - £:~~yl.b.n:en.
!MIlBR ... 4-_~yl-2-p.n1:anon.
5DI 12/SJ
~IaJ: 0/160
........... JJ.
=
=
...
!'IIUt{
0/10 '$35 ~
0/. /I'lL
...
370: ...
us,
~ '4/100
oa 0/200
laD 0'"0
500/:.100
:'0.,)00/41.,)00
21/1.000
2.100/9.000
500/2.100
c
o
,SS.
t '''5
':'C:"'!: :00/"0
ilCr 6/210
SD 'lO/1.':'OO
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n:. 1701 J. .00
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.
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'ME. 22/22.000
DD' 0/.40
:rn. 520200
I
.r
o
.,11 I Crolld 'oter 501llpli.9 locoliu
Conc.n~:':s~ions in .,ar-:s per :'illion
and pres.n~.d as 1.985/1990.
Sc.t. ,: 1,110
"'
Figure 1 8
CONTAMINANT MIGRATION
TI88ErTS ROAD, BARRll/CTOtl, HH
"'
1111..t
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION - SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE
95
I-
TTBBE1"!'S ROAD SrrE
I T..ncJ>
8/
Tronch ............
1
,
o
-'
-\
,
.
I
Vacuum
E.x.D'acaon
BROWN SANDY nu..
~ ~~-'--- ~- ~.~ ~ ~~r~'~':~'~'-","'~:~- - -. - -- --
BEDROCX
Recovery
,/:..c~'.. - _-1
.-'
On-si.. bcdmck artdIo: ovaburdcn
aquilu injcclJon of created groundwa=
(Allem..... ~M-7 only)
CROSS SECTION A.A'
\\
~..
...
13
I
K
CI
13 Prop."d ".Ihu.d Bcdroc.
Woait""9/E.t,acti.. ..11
am Pr.,," hildi.9
IZJ V".um ElI,.cti.. Arta
SUi' I' 1."0 In
Figure 19
CONCEPTUAl SIT! IIAN
AND Cia!! !ICTION
TIBBETTS ROAD. BARRINCTON. NH
h.,,, S.. "1112:'"
I..,u .,n .,t: Cn"" ,.,.""..u I... II 111.
10'
2"'"1
-------
OrowidWllcr from
Trench,,'
Recovery WeD(1)
Uld Vacuwn
!!ulaclion Well.
(S 10 10 gpln)
Me~al.
Pl-ccipila.ion
OAC ".cd Pump
Slud&e 10
--. Disposal
«4 rl]/day)
- ~ Spcol Carbun
r- 10 Dispoll'
Uquid Phuo
OAC
Unl.. (optional)
Tlealed
Waler 10
Dischuge
Air Sllipl>cr
Feed PWllp
[Q;
Air Sllillpel
Ulower
Air
Siripper
TIUUI~rI'S ItOAU SITI~, UAIUUN(,TON, NI':W IIAMI1Sllilm
FEASIII'UTV STlJUV IUo:l'Oln
GlUUlNUWATI.:R 1'HUTMIo:NT SYSTEM
Al.n:RNA'nVE MM.6
To
Atmosphere
-~. SpeRl
Car"'.nlo
DisIN...1
Vapul Phase
Carbon Uni..
(()pcrating in
eilher .eries
or parallelt
~~
OtJJ
OtJJ
~~
t-]
OU)
hJ
:;tI
tJO
~E;
H
U)U)
He:
0'0
Z(11
I~
U)~
(11tJ
'0
t-]U)
(11H
:S:t-]
tJJ(11
(11...
::u
tJJ
~~
H
""'Z
\DI;)
\Dt-]
NO
Z
...
z
(11
~
~
to
U)
:z:
H
~
'V
~
(,)
I:'J
Fi 'lire 2 0
\D
-------
AI,
OrOWldwllCl rrom
Treneh.,/
Recovery Well(l)
and Vacuwn
Eluaclion Weill
(5 10 101pm)
Mela"
Precipilallon
Supcmllanl
Sludge 10
--,. Dispoul
«4 fI3/dIY)
CI.1J1I Off Gas
CllllY1ic Ozone
Decomposer
(Remove. Ozone)
Syll.m Off Gas
UVOXlDAll0N
SYSTEM
lIydrogen
Pcroaide I'Iunp
(!'rom Feed Tank)
TIRmnTS nOAn SITI~, UAIUUNGTON, NEW IIAMI'Sllllm
FEASIUIUTY S'I'lJUY IWI'OItT
GltOUNDWATI-:R TREATMENT svs'mM
AI.n:RNAl1VES MM-5 & MM-7
,6
Trelled Wlter
III Discharge
~~
OU:!
OU:!
~~
t-3
OU)
ITJ
~
00
~~
H
U)U)
HC
OtO
ZI:>1
I~
C
U)Z
pJ 0,
to
t-3U)
I:>1H
ffi~
1:>1"
~
U:!
~~
H
I-'Z
~G)
~t-3
NO
Z
..
Z
1:>1
~
~
to
U)
p::
H
~
to
;JOA
(,)
[lJ
Fi 'lire 2 1
\D
-------
APPENDIX B
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 99
Table 1
GROUND WATER CONTAMINANTS IN THE OVERBURDEN AND BEDROCK AQUIFERS
- - -
VOLATI LE ORGAN I C COMPOUNDS
ben z .ene 7 / 2 9 2 8 - 1 , 1 0 0
1 2 / 2 8 2 - 3 , 0 0 0
1 , 2 di c h 1 0 r 0 e t hy 1 e ne ( t ot a l ) 3 / 2 9 2 - 4 , 0 0 0
5 / 2 8 1 8 - 1 , 1 0 0
et hy lben z ene 5 / 2 9 3 6 0 - 1 , 7 0 0
2 / 2 8 1 , 1 0 0 - 1 , 5 0 0
4 -met hy 1 ~2 -pent an one 1 / 2 9 1 0 , 0 0 0
6 / 2 8 2 0 - 4 1 , 0 0 O
s t y re ne 0 / 2 9 ND
1 / 2 8 3 3 0
t et r a ch 1 0 roet hy 1 ene 4 / 2 9 2 - 1 3 0
2 / 2 8 1 3 0 - 2 1 0
t 0 1 uen e 5 / 2 9 3 3 0 - 1 2 , 0 0 0
4 / 2 8 4 - 5 , 4 0 0
1 , 1 , 1 t r i ch 1 0 r oet :!;lane 0 / 2 9 ND
1 / 2 8 2 2 0
t r i ch 1 0 ro et hy 1 ene 4 / 2 9 9 - 7 , 8 0 0
1 2 / 2 8 4 - 6 5 0
x y 1 ene 6 / 2 9 7 6 0 - 5 , 4 0 0
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 100
Table 1, (Continued)
SEMIVOLATILB ORGANIC COMPOUNDS
bis(2-ethylhexyl)phthalate
1/17
1/24
5/17
1/24
5/17
3/24
2-methylnaphthalene
naphthalene
INORGANIC SPECIES (Unfiltered data)
arsenic
. 16/19 .
7/7
18/19
6/7
16/19
4/7
19/19
7/7
18/19
4/7
18/19
5/7
chromium
lead
manganese
nickel
vanadium
8
240
5 - 40
2
52 - 455
36 - 145
4.8 - 185
18.2 - 80
5.3 - 353
7.2 - 514
13.9 - 220
8.2 - 221
254 - 19,900
43.9 - 11,400
15.7 - 252
21.4 - 401
20.5 - 290
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 101
Table 2
CONTAMINANTS OF CONCERN IN GROUND WATER
1iIiII1ML:811
VOLATILZ ORGANIC COMPOUNDS
benzene 95 1,100 7/29
333 3,100 12/28
1,2 dichloroethylene 152 4,000 3/29
. (total) 60 1,100 5/28
ethylbenzene 308 1,700 5/29
100 1,500 2/28
4-methyl-2-pentanone 382 10,000 1/29
621 41,000 6/28
styrene ND ND 0/29
14 330 1/28
tetrachloroethylene 159 130 4/29
27 210 2/28
toluene 1,958 5,400 5/29
320 12,000 4/28
trichloroethylene 334 7,800 4/29
73 650 12/28
1,1,1 ND ND 0/29
trichloroethane 10 220 1/28
xylene (total) 1,563 5,400 6/29
258 .3,100 3/28
SEMIVOLATILZ ORGANIC COMPOUNDS
bis(2-ethylhexyl) 6 8 1/17
phthalate 14 240 1/24
2-methyl naphthalene 11 40 5/17
5 2 .1/24
naphthalene 77 455 5/17
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 102
Table 2, Cont.
INORGANIC SPECIES (METALS)
lead
49 185 16/19
30 80 7/7
97 353 18/19
126 514 6/7
38 220 16/19
61 221 4/7
5,992 19,900 19/19
4,896 11,400 7/7
69 252 18/19
107 401 4/7
97 290 18/19
133 554 5/7
verage concentrat~ons ~n r~s assessment a so.cons~ er
those samples that were below detection. In calculating the
averages those samples that are below detection are given a
value of one-half the detection limit of the method used.
arsenic
chromium
manganese
nickel
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 103
Table 3
CONTAMINANTS OF CONCERN IN SOIL
~-
VOLATILE ORGANIC COMPOUNDS
methylene chloride 32.8 90 3/19
tetrachloroethylene 45.7 650 2/19
toluene 1 .1 3/19.
trichloroethylene 3.5 11 4/19
SEMIVOLATILB ORGANIC COMPOUNDS
bis(2-ethylhexyl) 419.8 770 4/19
phthalate.
benzo(a)pyrene 93 93 1/19
benzo(b)fluoranthene 98 98 1/19
di-n-butylphthalate 210 210 5/19
Aroclor 1260 279 760 2/19
Table 4
CONTAMINANTS OF CONCERN IN SURFACE WATER
................... .::m~1:~"liiilli\lllil.i\
.dtlMtl;:M:M~~:;~i::I.il!~:\:\:\
VOLATILE ORGANIC COMPOUNDS
benzene
ethylbenzene
1
16
toluene
trichloroethylene
110
9
xylene (total)
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 104
Table 5
PRESENT CARCINOGENIC RISK FOR SOIL AND SURFACE WATER
Average and Maximum Concentrations
11111.1111::::iM::m;~1Imf:m:
!i::j:li!:f!I:lillll!!!~I!I~;::~\j!1!1:!j~I:!
,:;...:...JIII.11111111111111111111111111Iilllll~ll.lliilll1111I11
Ingestion of
Soil
Dermal Contact
with Soil
Not Evaluated
5.04 X 10-07
5.04 X 10-07
Not Evaluated
1.97 X 10-07
1.97 X 10-07
Ingestion of
Surface Water
Dermal Contact
with Surface
Water
4.81 X 10-09
4.12 X 10-09
8.93 X 10-09
9.00 X 10-09
1.91 X 10-08
2.81 x 10-08
Ingestion of Not Evaluated 7.07 x 10-07 7 . 07 x 10-07
Soil
Dermal Contact Not Evaluated 3.72 x 10-07 3.72 X 10-07
with Soil
Ingestion of 4.81 x 10-09 4.12 x 10-09 8.93 X 10-09
Surface Water
Dermal Contact 9.00 x 10-09 1. 91 x 10-08 2.81 x 10-08
with Surface
Water
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE
105
PRESENT
Table 6 .
NON-CARCINOGENIC RISK FOR SOIL AND SURFACE
Average and Maximum Concentrations
WATER
Ingestion
of
Soil
;::;-II\~lllll.lllllillllli!'II'llilll~I'llllllilllllliIlilliliillllill
:I;:::::!!::it:::it\~i:m:~lilillllll~IIIIIIIIII.lil;'11111i\
Eval uated.
Not
0.0000146
;111111\1\11I1:li~~;;!~:;~![i1illiii::::il;~~mi::i1ii:i:i~lliili
Dermal
Contact
with
Soil
Not
Evaluated.
0.00000959
0.0000703
0.0132
Dermal
Water
Contact
with
Surface
0.000328
0.0248
Ingestion
of
Surface Water
~
Dermal
Contact
with Soil
Not
Evaluated.
.1;!::1al~I.I.I::1:::!::
.iifiNtiID1!\;lIBli:!\1\!\i\!\!:!:!:i\!\!\;
0.0000554
0.0000910
0.0000703
0.0132
Ingestion
of
Soil
Not
Evaluated.
Dermal
Water
Contact
with
Surface
0.000328
0.0248
Ingestion
of
Surface Water
0.0134
1t:~?''':«~III''IIII;IIIIIII''I''I'I~1111111111
urrent r~s s or young c ~ ren were not eva uate ecause
the current Site fence will eliminate or severely limit
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 106
Table 7
POTENTIAL FUTURE CARCINOGENIC RISK FOR SOIL, SURFACE
GROUND WATER FROM OVERBURDEN AND BEDROCK AQUIFERS
Average and Maximum Concentrations
WATER, AND
Ingestion of 3.13 x 10-06 1.34 x 10-06
Soil
Dermal Contact 6.00 x 10-07 5.12 x 10-07
with Soil
Ingestion of 4.81 x 10-09 4.12 x 10-09
Surface. Water
Dermal Contact 9.00 x 10-09 1. 91 x 10-08
with Surface
Water
Ingestion of Ground Water (Thirty year
exposure)
4 . 47 x 10-06
1.11 X 10-06
8.93 X 10-09
2.81 x 10-08
Shallow wells
1. 17 x 10-03
Bedrock wells
7.60 X 10-04
Soil, Surface
Water, and
Shallow wells
1.18 X 10-03
Soil, Surface
Water, and
Bedrock wells
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 107
Table 7, Continued
POTENTIAL FUTURE CARCINOGENIC RISK FOR SOIL, SURFACE
GROUND WATER FROM OVERBURDEN AND BEDROCK AQUIFERS
Average and Maximum Concentrations
WATER, AND
lil18IIII!!iI1Ilil!i!ill! ::::ill.~I!:~!!::::':::.:::.:::::.:::
:::::::IIIII~I!!::::::!:i:!l:~l[:!!ii!:I:I:i:l!!I!:~i!:11!:ii!:!I!I:i:!~11!:i;;!I~:!iiili!::!::i!ili:::!i:::i:
:;".:.:nm::::H!!!I'IIIII!tllllllllllllll~III!:lilllil!!ililI111
Ingestion of
Soil
Dermal Contact
with Soil
4 . 3 9 x 10-06
1.87 X 10-06
6.26 X 10-06
1.15 X 10-06
9.83 X 10-07
2.13 x 10-06
Ingestion of
Surface Water
Dermal Contact
with Surface
Water
4.81 X 10-09
4.12 x 10-09
8.93 X 10-09
9.00 X 10-09
1. 91 X 10-08
2 . 81 x 10-08
Ingestion of Ground Water (Thirty year
exposure)
Shallow wells
6.66 x 10-03
Bedrock wells
2.52 X 10-03
Soil, Surface
Water, and
Shallow wells
6.67 x 10-03
Soil, Surface
Water, and
Bedrock wells
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 108
Table 8
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR SOIL, SURFACE
AND GROUND WATER FROM OVERBURDEN AND BEDROCK AQUIFERS
Average Concentrations
WATER,
11:III'II!!IIIIII'I!'II,III:'lllllltllllllllllll!11111i
Ingestion of Soil
Dermal Contact with Soil
0.000364
0.000119
0.000328
0.0248
0.0000386
0.0000253
0.00.00703
0.0132
. Ingestion of Surface Water
Dermal Contact with Surface
Water
Ingestion of Ground Water (Thirty year
exposure)
Shallow wells
5.66
Bedrock wells
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 109
Table 8, Continued
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR SOIL, SURFACE
AND GROUND WATER FROM OVERBURDEN AND BEDROCK AQUIFERS
Maximum Concentrations
WATER,
Ingestion of Surface Water
Dermal Contact with Surface
Water
0.000328
0.0248
0.0000554
0.0000910
0.0000703
Ingestion of Soil
Dermal Contact with Soil
0.001.38
0.00113
0.0132
Ingestion of Ground Water
(Thirty year exposure)
Shallow wells
42.10
Bedrock wells
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 110
Table 9
POTENTIAL FUTURE CARCINOGENIC RISK FOR GROUND
In the Overburden and Bedrock Aquifers
Average Concentrations.
WATER
III .e;linn nf Grol/lldw:ller . Shallow Wells
Chal/icals of
ConctnI ill Shallow Wells
bc:nz.ene
1,2'<1ichloroclhem: (11I1al)
elhyll>o:nzene
4-melhyl-2-pcnlanone
lelrachloroelhene
toluene
I,I.I-trichloroethane
lrichloroelhene
xylene (Iolal)
bi 5(2 -.:th y Ihex yl)phlhalale
2-melhylnaphlhalene
naphlhalene
arsenic
chromium
Chronic I}aily
Intake" Ages I . 30
m Ik -d.
1.11 E.{IJ
1.78E'()J
HOE-OJ
4.47E.{IJ
1. 86E.{IJ
2.29E.02
NA
J.9IE-OJ
, 1.8JE.{I2
7.02E.{IS
1.29E.{14
9.0IE-Q4
S.7JE-Q4
1. JJE'()J
4.4SE-04
7.0IE-02
8.07E-04
I.JJE-OJ
lead
Averolge Conccnlralions
mIl
O.09S
0.IS2
0.308
0.J82
0.IS9
1.9S8
ND
0.JJ4
1.S6J
0.006
0.011
0.077
0.049
0.097
0.038
S.992
0.069
0.097
,manganese
nickel
vanadium
In eslion of Groundwaler . D
Wells
Orlll Canccr
rolency Fac:lor
m Ik ..da .1
2.90E.{12
NA
NA
NA
S.IOE:02
NA
NA
1.J0E.{12
NA
1.40E-02
NA
NA
I.7SE+oo
NA
NA
NA
NA
NA
Tolal l'alhwa Risk =
Wells
Chl'1l1ic:als of
Cllnrcm ill Ot
ben Zene
1.2.dichlorocthene (1IIIal)
elhylhcnzene
4-mclhyl-2-pcntanllllc
styrene
letrachloruelhent:
A verolge ClIIlI:l'1l1r.alioIiS
on II
O.JJJ
. 0.06
0.1
0.621
0.014
0.027
U.32
0.01
0.073
0.2S8
0.014
O.OOS
0.017
0.03
0.126
0.061
4.896
0.10,7
O.I3J
J.90E-OJ
7.02E-Q4
1.11E.03
7.21E.OJ
1.64E-04
3.16E-04
3.74(;-0]
1.17E.{14
8.S4E-04
].02E.{I]
1.64(;.04
S.8SE.{IS
I.99E-04
3.S IE.Q4
1.47E.{I]
7.14E.04
S.7JE-02
I.2SE.03
I.S6E-03
lohlcne
I. 1 ,I-Irichloroclhanc
lrichloroethcne
xylene (Iolal)
bis(2 -ethy Ihex yl)phlhalate
2-melhylnaphthalene
naphlhalene .
arsenic
chromium
.I....d
manganese
nickel
vanadium
Oral Canccr
I'oh:nc:y Fador
IIII:lk .da -I
2.90E.02
NA
NA
NA
3.ooE.02
S.IOE.02
NA
NA
I.IOE-02
NA
1.40E-02
NA
NA
I. 7SE +00
NA
NA
NA
NA
NA .
Tolal Palhway Risk =
Cln:mic:al-Spl,;ific
Carcinogenic
Risk
3.22E-oS
9:49E-OS
4.JOE.{IS
9.83E-07
I.OOE-03
1.17£.03
Chl'1llicOlI-Sl'l,;ific
CarcilloJ:l'1lic
Risk
1. 13E.II4
4.9IE-06
1.61E-oS
9.40E-06
2.291:-06
6.14E-D4
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 111
Table 10
POTENTIAL FUTURE CARCINOGENIC RISK FOR GROUND
In the Overburden and Bedrock Aquifers
Maximum Concentrations
WATER
In .eslinn of Groundwater - Shallow Wells
Oral Cancer
Chernicals of Maximum Concentrations Potency Faclor
Concern in Shalluw \Veils mil In '" -da \-1
benune 1.1 1.29E-02 2.90E-02
. 1.2-.JichlorOClhene (Inial) 4 4.68E-02 NA
ethylbenz.cne 2.5 2.93E-02 NA
4 .melhyl-2.pc:ntanolle 10 1.1 1E-O I NA
lelrachloroc:thene: 2.5 2.93E-02 5.IOE-02
toluene: 12 1.40E-OI NA
I. I .I-Irichloroelhane: ND NA NA
trichloroelhene: 1.8 9.13E-02 1.1 OE-02
xylene (Iolal) 18 2.11 E-OI NA
bis(2~thylhe:xyl)phlhalale: 0.01 I.I1E-04 I. 40E-02
2.mc:lhylnal'hlhalene 0.04 4.68E-04 NA
narhlhalene 0.4SS 5.32E.03 NA
arsenic 0.185 2.16E-03 1.751:+00
chromium 0.353 4.I3E-03 NA
lall 0.22 2.51E-03 NA
manganese 19.9 2.33E-01 NA
nickel 0.252 2.95E-03 NA
vanalliom 0.29 3.39E-03 NA
Total Pathw-ol Risk =
In 'estion of Groundwaler - D Wells
Chronic D:ail, Or:al C:ancer
ChcrniCils uf l\Iaxinnun Cuncenlrolliuns Intake - AGes I - 30 I'nlcncy "aclur
Concern in I>~-,: Wells m,lI (m'''' .-da lalll!/k . .lIa H
!>cn zene 3.1 3.63E.02 2.9OE.02
1.2.dichlurnclhcllc (Inial) 1.1 1.29E.02 NA
elhylbenz.cne I.S 1.16E-02 NA
4-me.hyl-2 'pc:nlallolle 5.5 6.44E-02 NA
slyrene: 0.J3 3.86E-03 3.ooE-02
.elrachloroclhene 0.25 2.93E-03 5.IOE-02
Inillene 5.4 6.32E-02 NA
. J. J . I-trichloroclhane 0.22 2.51E-03 NA
IrichlorOC:lhene 0.65 1.61E-03 1.I0E-02
xylene (Iolal) 3.1 3.63 E-02 NA
bis(2 ~Ih ylhe. yl)phlhalale 0.24 2.81E-03 1.40E-02 .
2-mclhylnaphlhalene 0.005 5.85E-05 NA
Daphlhalenc 0.145 !.10E -03 NA
arsenic 0.053 6.20E-04 1.15E+OO
chromium 0.514 6.01E-03 NA
lead 0.221 2.59E-03 NA
manganese 11.4 1.33E-01 NA
nickel 0.401 4.69E-03 . NA
vanallium 0.554 6,48E-03 NA
Tolal Palhw:a Risk =
ChcmiQI-Spt.ocific
Carcinogenic
Risk
3.13E'{)4
1.49E-03
I.OOE.03
1.641:-06
3.79E.03
6.66£-03
CIII:UliQI-SI'~'dfic
Carcinllj;cnic
Risk
1.051:.(13
1.161:.04
1.49E.Q4
8.31E-05
3.931:-05
I.09E-03
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 112
Table 11
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR GROUND WATER
In the Overburden and Bedrock Aquifers
Average Concentrations
In eslion of Groundwater. Shallow Wells
Chronic Daily Chronic Oral Chanical-Specilic
Clumicals of Anrnge Concentrations Inlake . Ages I . 30 Rd'eraICe Dose Noncarcinogauc
Concem In Shallow Wells mil m /Ie eda mllc-da. lIuard Index
beDzene 0.095 2.60E-OJ NA
1.2edicbloroclhene (Iotal) 0.152 4.16E-OJ 1.00E-02 4.16E-01
ethylbenune 0.308 8,44E-OJ 1.00EoOi 8.44E-02
4-methyl-2.peaIaaODe 0.382 1.051!-G2 5.ooE-02 2.09EoOl
lelrachloroclheae 0.159 4,36E-03 1.00E-02 4.36EoOl
loluene 1.958 5.36E-G2 2. ooEoO I 2.68EoOl
I, I,I-tricbloroethane ND NA 9.ooE-G2
tricbloroetheae 0.334 9.15E-03 NA
Iylene (10111) 1.S63 4.28E-G2 2.ooB+00 2.14E-02
bis(2 -elhylbel yl)phlhaJate 0.006 1.64E-04 2.ooE-02 8.22E003
2-melhylnlpblhalene 0.011 3.0IE-04 4.ooE003 7.54S-02
D1rblhaJene 0.011 2.IIE003 4.OOS003 5.27S001
arsenic 0.049 1.34E-03 l.OOS003 1.34n+00
chromium 0.097 2.66E-03 5.ooE003 5.32EoOl
lead 0.038 J.04EoOJ NA
In8IIganese 5.992 J.64EoOl 1.00EoOi 1.64E+oo
Dickel 0.069 1.89E003 2.ooE-02 9.4SE-02
vanadium 0.097 2.66E-OJ 9.00E003 2.9S2001
Total rlllhwa lIazard Index = S.66E+OO
In eslilln of Groundwaler. Wells
Chronic Daily Chronic Oral Chanic.al-Specilic
Chanicals of AYa1IJ:e Concentrations Intake. Ages I - 30 Reference Dose Noncarcinogenic
Concem in Wells mil m /Ie -da m /Ie eda . lIazard Index
benzene 0.333 9.12E-03 NA
1.2-dicbloroelhene (101a1) 0.06 1.64EoOJ I. 002-02 I.64EoOl
elhylbenzeae 0.1 2.74E-03 1.002-01 2.742-02
4-methyl'2'penlaaoae 0.621 1.70E-G2 5.ooE-02 3.40EoOl
II yrene 0.014 3.84E-04 2.002.01 1.92B-03
IelrachloroctheDe 0.027 7.40E-04 1.00E-02 7.40E-02
loluene 0.32 8.711:.03 2.ooeoOl 4.388-02
I.I,I-trichloroethane 0.01 2. 74E-04 9.ooB-02 3.04E003
lricbloroethene 0.073 2.ooE003 NA
xylene (101&1) 0.258 7.07E003 2.ooS+00 3.53E003
bi&(2 -ethylhea yl)pbthalate 0.014 3.84E-04 2.ooE-G2 1.92E-02
2 .meth yJnarblhaJeae 0.005 1.378-04 4.ooE003 3.43E-02
OIJ'bthaleae 0.017 4.66E-04 4.ooE-oJ 1.16EoOl
&t&OIIic 0.03 8.22E-04 l.ooS003 8.22EoOl
chromium 0.126 3.4SE003 S.ooe003 6.90EoOl
lead 0.061 1.67S-03 NA
raan glUtellO 4.896 1.34EoOl 1.00eoOl 1.34E+00
aiclcel 0.107 2.9JE003 2.ooE-02 1.41EoOI
vuwiium 0.133 3.64E003 9.OOS-03 4.OSE-ol
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW F~~PSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 113
Table 12
POTENTIAL FUTURE NON-CARCINOGENIC RISK FOR GROUND
In the Overburden and Bedrock Aquifers
Maximum Concentrations
WATER
In eslinn of Groundwater. Shallow Wells
Chronic Duily Chronic Oral Chanical-Specific
Chemicals of Muimwn Coneentralioll.s Inlake . Ages 1 .30 ReI'erence Dose Noncarcinogenic
Concern in 5hallow Wells mil m Ik -da m Ik -eta . Hazard Ind~
ben zene J.J 3.0 11!~2 NA
1.2-dic:hloroelhene (Iolal) 4 I.lOI!~l 1.OOE~ I.lOE+OI
elhylbenzene 2.S 6.8SI!~2 I.oon-GI 6.8SB~1
4.methyl-2-penlaDoae 10 2.74E-01 S.ooE-02 S,4SE +00
I.elruhJoroelhene 2.S 6.8SB~ 1.00E~ 6.8SB+00
!Dlueae 12 3.29E~1 2.ooB-G1 1.64E+00
I,I,I-tric:bloroethane ND NA 9.ooE-02
tric:hJoroetbeae 7.8 2.14E~1 NA
Iyleae (!Dial) 18 4.93B~1 2.008+00 2,47B-G1
bi&(21:th ylhelyl)pblhalat.e 0.01 2. 74B~ 2.008-02 1.37E-02
2-lIIdhylll8pblhaleae 0.04 I.I0B-03 4.ooB-G] 2.74E-G1
napbthalene 0.45S I.25E-02 4.ooE-G] 3.12E +00
.rsea.ic 0.185 S.07E.o3 I. 000,.03 S.078 tOO
chromium O.JSJ 9.67E-OJ S.ooe-03. 1.93E+00
lead 0.22 6.03E~3 NA
manganese 19.9 5.4SB~1 1.008-01 SASn +00
Dickel 0.252 6.90E~3 2.ooE-02 3.4SE~1
Y&JIadium 0.29 7 .9SE~3 9.ooE-G] 8.83E~1
Total Pulhwa Hazard Indes = 4.2IE+01
In eslion of Ground_ler - D Wells
Chronic Daily Chronic Oral Chanical-Specific
Chemicals or Muimwn Coneentnations Intake - Ages 1 .30 ReI'erenc:e Dose Nuncarcinogenic
Concern in Wells mil m Ik -da m Ik -eta . Hazard Indes
benzene 3.1 8.49E-02 NA
1.2...Jjc:bloroethene (Iutal) J.J 3.0IE-02 1.00E-G2 3.0IE+00
eth y lbe:az.cne I.S 4.IIE-02 1.00E-G1 4.IIB~1
4-methyl-2-penlaDon8 5_S I.SIE~I S.ooE-02 3.0IE+00
stYmie 0.33 9.04E-03 2.ooE-01 4.52B-G2
IelruhJoroetbene 0.25 6.8SE-03 I. ooE-02 6.8SE-01
!Dluene S.4 1.48E-OI 2.oon-G1 7.40B-01
1,I,l-trichJoroethute 0.22 6.03E-03 9.008-02 6.70E-G2
tricbloroetheae 0.6~ 1.78E-02 NA
Iylme (1Dta1) 3.1 8.49B-02 2.008+00 4.258-G2
bi&(2~thylhelyl)pblhalat.e 0.24 6.S8E-G3 2.008-02 3.29E-01
2-mcthylll8pblhaleao 0.005 1.]7E~ 4.ooE"()] J.43E-G2
aapbthaleae 0.145 3.97E-03 4.ooa-O] 9.93E-01
arseaic 0.053 1.45E-03 I.ooa-O] 1.458+00
cbromium 0.514 1.4 I E-02 5.ooE-03 2.82B+00
lead 0.221 6.06£-03 NA
maD g ane&e 11.4 J.12E-01 1.00E-Oi 3.12E+OO
Dic:kel 0.401 J.JOE-02 2.ooE-02 5.49E-01
vanadium 0.554 1.S2E-02 9.00E-03 1.69E+00
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 114
ECOLOGICAL
Table 13
CONTAMINANTS OF CONCERN FOR SURFACE WATER AND
SEDIMENTS
using maximum concentrations
. ~:ii~!:~;i~!.!!!!!i[
toluene
trichloroethylene
5,300.
32,000.
17,500.
45,000 / 21,000
Not Available
41
360
benzene
ethylbenzene
330
10
760
methylene chloride
4-methylphenol
Not Available
Not Available
1 - 7
79
83
19
There are insufficient data to develope these criteria.
These concentrations are the Lowest Observed Effects Level
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON,
RECORD OF DECISION SEPTEMBER 29, 1992
NEW HAMPSHIRE
PAGE
115
Table
ALTERNATIVES
14
DEVELOPED
REMEDIAL
ALTERNATIVE
DESCRIPTION OF
COMPONENTS
(The shaded alternatives were
unshaded were eliminated)
i:iil!i!:ii:ii[j:!:!i!:!i:ii:i_I!I!!i:!:ii:iiiil.~~iiili:::iiilli::ii!I~11111i~i!il!!:!!~!ii!I!lli!ili:!:!:i:!i!liiiiil:!:!:i::!:i!II!:!!I:ii!iii!i!:!:II!!!!!i:ilil!i::I:llllli:!il!!i:!:!!!iillri.il!!!!:!II!:11\1iiiiij!,!I:i:!:!!III:!]i!:!I!;\!!~1!!ilil:i!!:i'!:ii!ii!:ii:li::i!iii::iii!iiii::!i::!::i:;:ii::
retained,
the
-~
MM-3
situ biological
Contains the components of alternative MM-2,
ground water extraction and treatment, and Soil
vacuum extraction. Extraction of contaminants
will occur through recovery trenches and/or
wells. Treatment will capture metals and
capture organic contaminants with air stripping.
Discharge of treated water will be to on-site
recharge beds.
In
treatment.
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 116
REMEDIAL DESCRIPTION OF COMPONENTS
ALTERNATIVE
(The shaded alternatives were retained, the
un shaded were eliminated)
MM-8 Contains the components of alternative MM-2,
ground water extraction and treatment, and Soil
vacuum extraction. Extraction and treatment of
contaminants is identical to MM-4; however,
discharge of treated water will be to a
publically owned treatment works (POTW).
Those alternatives that are shaded were retained for further
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 117
Table 15
SUMMARY OF ESTIMATED PRESENT WORTH COSTS
194-1 No Action
194-2 Institutional
Controls, Alternate
Supply Improvement,
Monitoring
o
383,400
o
642,500
Water
and
Recovery,
Treat
and Off-
2,228,190
2,169,500
194-5 Ground Water
Vacuum Extraction,
with UV-Oxidation,
site Recharge
MM-6 Ground Water Recovery,
Vacuum Extraction, Treat
with Air Stripping, and
Surface Water Discharge
1,897,060
2,769,070
194-7 Ground Water Recovery,
Vacuum Extraction, Treat.
with UV-Oxidation, and On-
site Well Injection
1,728,690
2,046,970
o
1,025,900
4,397,690
4,666,130
3,775,660
A detailed breakdown of an estimate of the costs is contained in
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 118
Table 16 .
INTERIM GROUND WATER CLEANUP LEVELS
1,2 Dichloroethene MCLG Blood
(cis) (D) 70 0.19
(trans) (D) 100 0.14
Ethylbenzene (D) 700 MCL Kidney & 0.19
Liver
4-Methyl-2- 1,825 Risk Kidney & 1. 00
.pentanone (D) . Liver
Styrene (C) 100 MCL Blood & 0.014
Liver
Toluene (D) 1,000 MCLG Kidney & 0.14
Liver
1,1,1 200 MCLG Liver 0.06
Trichloroethane (D)
Xylene (D) 10,000 MCLG CNS-DBW 0.14
Naphthalene (D) 1,460 Risk DBW. 1. 00
Chromium (D) 100 MCLG No effect 0.55
Manganese (D) 3,650 Risk CNS 1.00
Nickel (D) 100 MCLG DBW 0.14
Vanadium (D) 256 Risk No effect 1. 00
Blood
Kidney
Liver
0.344
1. 33
1. 404
1.28
1.14
Decreased Body Weight (DBW)
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TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 119
TABLE 16, (cont.)
INTERIM GROUND WATER CLEANUP LEVELS
Benzene (A) 5 MCL 1.7 x
Tetrachloroethylene (B2) 5 MCL 3.1 x 10-6
Trichloroethylene (B2) 5 MCL 6.4 x 10-7
Styrene (C) 100 MCL 3.5"x 10-5
Bis(2- 4 MCL 6.6 x 10-7
ethylhexyl)phthalate (B2)
Arsenic. (A) 50 MCL 2.0 x 10-4
Sum: 2.4 x 10-4
1
2
3
Standard exposure parameters from OSWER Directive 9285.6-
03 for residential ingestion of potable water (i.e., adult of
seventy kilogram body weight drinks two liters of water per day
for 350 days for a" thirty year duration) are the basis for
calculation of risk-based cleanup level, hazard quotient, and
level of risk.
2 Toxicity values (i.e., RfD or CPF) used for calculation
of "risk-based cleanup level, hazard quotient, and level of risk
are from either the on-line IRIS or FY 1992 HEAST.
3 The cleanup level for arsenic has been set at the MCL of
50 ~g/l. The carcinogenic risk posed by arsenic at 50 ~g/l in
ground water will approximate 2 in 1,000. However, in light of
recent studies indicating that many skin tumors arising from oral
exposure to arsenic are non-lethal in nature and in light of the
possibility that the dose-response curve for the skin cancers may
be sublinear (in which case the cancer potency factor used to
generate risk estimates will be overstated), it is Agency policy
to manage these risks downward by as much as an order of .
magnitude (x 10). As a result, the carcinogenic risks for
arsenic at this Site have been managed as if they were 2 in
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 120
TABLE 17
WATER QUALITY STANDARDS AND CRITERIA
(All Concentrations are in ppb unless noted otherwise)
CW A Water CW A Ambient
Maximum Quality Water
Ground Water Safe Drinking Criteria for Quality Criteria
Concentration Water Act Protection uf fur Protectiun Safe Drinking Water Act Nil State
Compound Detected lIealth Advisories lIuman lIealth of Aquatic Life Criteria
(lifetime) (acute/chronic) MCL MCLO
Volatiles
4-Methyl-2-Pentanone 41,000
1,1,1- Trichloroethane 22S 200 18,400 200 200 200
Trichloroethylene 1,800 2.1 45n I ppm 5 0 5
(.
Tetrachloroethylene 210 0.8 5.2/0.84 ppm 5 0 5
Toluene 12,000 1,000 14,300 17 ppm . 1,000 1,000 2,000
Acetone 11,000
Etbylbenz.ene 1,520 700 1,400 32 ppm 100 700 700
Xylene. 18,000 10,000 10,000 10,000 10,000
t- 1 ,2-Dicbloroethylene 4,000 100 100 100 100
c-I,2-Dicbloroethylene 1,100 70 70 70 70
Methylene Chloride 3 S 0 S
Benzene 3,200 0.66 5.3 ppm 5 0 5
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
. RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 121
TABLE 17 (cant' d)
W ATEIt QUALITY STANUARDS AND CRITERIA
(All Concentrations are in ppb unlcss notcd otherwise)
CW A Water CW A Amhient
Maximu!11 Quality Water
Oround Water Safe Drinking Criteria for Qu,lIity Criteria
Concentration Water Act Protection of for Protection Safe Drinking Water Act Nil Slate
Compound Delecled lIeallh Advisories lIuman lIealih of Aquatic Life Criteria
(lifetime) (acute/chronic) MCL MCLO
Melals
Ar&enic 18S 0.0022 300/48 50 50
Lead. 22t 50 82/3.2 15. 0 50
Chromium 514 100 50 16/11 100 100 100
Nickel 40t too 13.4 1400/160 100 100
SA O. 130/S.3 0 (.
Beryllium 1,000
Manganese 19,900 SO
KEY:
-------
TIBBETTS ROAD SUPERFUND SITE, BARRINGTON, NEW HAMPSHIRE
RECORD OF DECISION - SEPTEMBER 29, 1992
PAGE 122
-------
CHEMICAL-SPECIFIC ARARs'
REQUIR:E;MENT
..
SYNOPSIS '.
.. .. . .......
P' .. ...
. ... ... .. .. .. ..... .... . ...
. ," ,",.. .."' ..",",," ,', ',"' '..",' .
Federal RegulatqryRequirEirnents.
SDWA - Maximum Relevant and
contaminant. Appropriate
Levels (MCLs)
(40 CFR 141.11
- 141.16,
141. 60 -
141.63)
SDWA - Maximum
Concentration
Limits Goals
(MCLGs) (40
CFR 141. 50 -
141.52) NCP 40
CFR 300.430
Ground Water
Protection
RCRA Subtitle
C, 40 CFR Part
264 - Subpart
F
Relevant and
Appropriate
Relevant and
Appropriate'
MCLs have been promulgated
for a number of common
organic and inorganic
contaminants. These
levels regulate the
concentration of
contaminants in public
drinking water supplies,
but may also be considered
for ground water aquifers
potentially used for
drinking water..
MCLGs are non-enforceable
health goals under the
Safe Drinking Water Act.
These requirements include
both concentration
standards and monitoring
requirements and
corrective action
requirements for regulated
units.
1
. .
The selected remedy will
attain MCLs.
The selected remedy will
attain non-zero MCLGs.
The selected remedy will
comply with the substantive
portions of the monitoring
standards and other
-------
, ",,', , " ,," ',"'", "', , . ' '.'"",',,' " ,." "" " '.. '" , ,
" ",' , .. : ',':':'" ,', .,' .,":,:","'.. "', , ',', '" ',', "","", :,:..,:,' ,: ',::, :',' ,",',::""', ,,' "',',"" , """,",' ," ',",.':.' " ':-:. , ,'" ,.:, '"',''' ,: "
ARAR~ HAND. CRITERI.A,...ADVISORIES, AND GUIDANCE . FORTHETIBI3ETTS~Ol\.1)SITEj.BARRINGTON,
NEW HAMPSHIRE. ........ .
CHEMICAL-SPECIFIC ARARs
REQUIREMENT.
Lead Treatment
Technique, 40
CFR Part 141
.. STATU~
.. ..
Relevant and
Appropriate
REQUI~EMEN'J;' SYNOPSIS
H
A lead action level
requires that certain
treatment steps be taken
when the action level is
exceeded.
. ...... . ...... ................ :..... . .......
State Regulatory Requirements
Former Section
Ws 410.05
GroundWater
Quality
criteria
To be
considered
. .....
..
Ws 410.05(a) prohibits
discharge of hazardous
waste to ground water.
Under Ws 410.05(e), no
substance designated in Ws
410 or which is harmful to
human health or the
environment may be
discharged to ground water
so as to exceed primary
MCLs. Also, under Ws
410.05(g), ground water is
not to be degraded in such
a way as to cause
violation of surface water
standards within or
adjacent to property.
2
ACTION TO BE TAKEN TO
ATTAIN ARAR
The selected remedy will
achieve the action level or
employ one or more
treatment techniques.
This regulation will be
considered and attained in
design of the reinjection
program to the maximum
-------
r~.~~i~1I.fl)i~~I\~tlil.i~~JI!.~lf~"'Gatt.a=~~~~1~il':i
.. .. . .. . . .... ....
.. ..".".'.".' ...,".",.' ..',".',',"..
. . . .. ..... . ... ." . . .' .. .",..
...RE.'."..'..'Q.'H.U.'H'..I'.. R'.'''.EM.. ....., HE.. N.T.. H.',.:. """"""",..
.:'~:.:.:>:':::: :..,..::':. ':~:::"""::'><:: : :;,:=::::.}:',-::\?rnr
P"
.... .
..."
.........
..-..."",-,,,
Former Ws
410.09 Ground
Water
Discharge
Criteria,
incorporating
by reference
RSA 485:1
Env-Ws 310
[Maximum
contaminant
Levels (HCLs)
and Maximum
contaminant
Level Goals
(MCLGs) ]
Former Ws
410.10
Additional
Criteria
To be
considered
. . ..
. ..... ..,....... . ... . .-. ...,...... . . .
,...:,~~gRf!!11~7)~~~~!;,!-;~~.;:;!:\::,:!:ilil::II\li:.1:i::~::::.:.:::\.:.'.~. ~~I~..'..:i.i.:~.'.g:.:s.'~.;.....i:.~..A.... :.:~.~#:'Tgt H"H HH.. .
. .,-.......-"........ .. ........--..'''''''''''' . ..'" . ....... ..
Ws 410.09 establishes
ground water discharge
criteria including MCLs
MCLGs, ~nd enforceable
Secondary MCLs, codified
in Ws Part 310, D~inking
Water Regulations., ..
., '
,
state MCLs, non-zero MCLGs
and enforceable Secondary
MCLs levels which are more
stringent than Federal
levels will be considered
for use as clean-up
criteria.
Ws 410.10 states that.".).~
ground water shall no~~be
altered in such a way! as
to render it unsuitable
for drinking water supply.
. ," .,.. .,","... ..." "", ," .....""'" -.. ... ....,......,..., ,. ,...' , ""." ""'., '",..,..,.,." .,.,.." . .....'.... " ',.,,' "",'.'..,'.',..,..'."...','
:t~a~'r~.l,pt~~~~~~:~:::":W~v~1~~rij$'~i.:.;~.ij~',:,,~~,~~~:ij~& ......HH ...H...H.'.......... :... .......... .HH.:..,....'....,:..... .. .....HH. . .. . ........... :... ,.;:. ",)(
EPA Risk To Be Rfds are dose levels EPA Rfds were used to
Reference considered developed by the EPA for assess noncarcinogenic
Doses (Rfds) noncarcinogenic effects. risks due to certain
contaminants in ground
water. .
To be
considered
3
The selected remedy will
restore ground water to a
level suitable for
-------
, '
. . " . .. .. . ..... . . . ......... . ....... ."" ..... ...... . ,",.. . ..
", ,", ,","",', "..e,',', . . ," ,", . ',". ",' .... .... p,", ," .,n,"..', ", ,"." ,',".." ".,.","., . ... ","".' n,',"..",."",'.. n.. .."..",,",'"'' "....",.. ,".. ".', , ",'n'... ',. "',... "..,"",',", ,',.' ,"' .
.......... ... . '"' . .." u..... . . ........ ....'.. ... ..'..-.. . ... . ....... ,,'.n..',' P" .-p' ....... . ... ....... .
ARARs,'ANrf, CRiTEt{:r~i .." !\QVXSQR:i:~S;'AtfDH'Gti1 PANct'i #.()~t~E.'I'~:BB~TtSH~Q.AD'S~~~{B{\RRINGTQN,
NEW HAMPSHIRE:> ,. ' ,:,'H, H'" ,.HH.":' ',,'. :'/
:. ,": "
CHEMICAL-SPECIFIC ARARs
'" :
"~
REQUIREMENT
CWA ~ 304, 303
Federal
Ambient Water
Quality
criteria
(AWQC) -
Adjusted for
Drinking Water
EPA Carcinogen
Assessment
Group Potency
Factors
STATUS
REQUIREMENT Sy~OPSIS
:- ,,"
To Be
Considered
Federal AWQC are
health-based criteria
'which have been developed
for 95 carcinogenic and
noncarcinogenic compounds.
To Be
Considered
Potency Factors are
developed by the EPA from
Health Effects Assessments
or evaluation by the
carcinogenic Assessment
Group.
4
ACTION TO ,BE TAKEN H TO
ATTAIN ,ARAR .,: , :
These criteria were
considered in
characterizing health risks
due to contaminant
concentrations in drinking
water.
EPA Potency Factors were
used to compute the
individual incremental
cancer risk resulting from
exposure to certain site
-------
ARAf{S :'AND..tRITEB:i~.i ..~:qy~~9,~*~$".;. :~p.(;tJ~p~~.CE:.i9~;:~it~::i,t>iBB~TTSR9~riSI'rli}:)3~INGTON,
NEWHAMPSHIR~.. ;.
. . .
. .
. .
LOCATION-SPECIFIC ARARs
REQUIREMENT.
~'l'~TpS
..
..
REQUIR~MENTSYNOPSIS
Federal Regulatory Requirements
Fish and Applicable
wildlife
Coordination
Act 16 USC !i
661 (40 CFR
6.302(g»
state of New
Hampshire
Ground Water
Protection
Act, .
NH RSA 485-C
This regulation requires
that any Federal Agency
that proposes to control
or structurally modify a
body of water must
consult with the u.s.
Fish and Wildlife
Services.
Relevant and
Appropriate
This statute contains
guidelines for certain
facilities that operate
in areas of specific
ground water
classification.
5
. .
.. . ....
ACTION TO BE TAKEN TO
ATTAIN.ARAR
u.S. Fish and wildlife
Service will be consulted
if diversion or other
activity modifies water
bodies and affect fish or
wildlife.
The construction and
operation of the remedy
will meet, and comply with,
the substantive standards
-------
",'.'., ",.,.,.,'". . ,.,.'" ,. ..,',..' '...',','."',,,.'.,.',,',..,' ..", .'. .','. .'. ',.."."", ','". ..,.",.,',.., ., ,",'.",.,',".',',.., ....',' ,. ,.,'., '".,'. . ,'.' "..' '.,...'" , "" ",' ...
".,. ",..',',,' ,.."'...',',., ',.,".'.'.",'.",',..".,.....,'..,'.',.."..','..',."'".,'.'.',... ','. .'.',.','...",'.',',.,.'.' "..,........ ,. ','. ,."..'.',',.,." ..',''','',',.''''',....,.,., .".,'." .',...,..,".",. ,.. "'.' ,.. ,....'''.,''..''.'' .. ". ...., ."",". ",",".',".,",'.'," .,
.... ..., '.' " .. ".. ".......,..... .,'.... ...",.."... . ......, ""'''.'''..'.',,, ,. . ........ ,.. .. ,. ".. """.'.'..,... .,.., ." " , " .,..." .. "".. "" ,.........".. .....".. ,.. ....
A~s ... ANt)CR~!~~~A/:J\9V!$Q~l~si'ANP/GtitbA,&qtit9R.TH~TtJ3BE'l'T$RQi\D$X':t'~;:,I.}~~~~T9Ni.,'
, NEWHAMPSHIRE:):> ...... ... .
1. Hazardous Waste
Regulations (RCRA
subtitle C, 40 CFR
Part 264)
a. General
Facility standards
(264.10 - 264.18)
(Subpart B)
b. Preparedness
and Prevention
(264.30 - 264.37)
(Subpart C)
c. contingency
Plan and Emergency
Procedures (264.50
- 264.56)
(Subpart D)
d. Ground
Protection
- 264.109)
F)
Water
(264.90
(Subpart
Relevant and
Appropriate
Relevant and,
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
.. , .., , ,
' .., , .
. ., ,
,g~QU:IJ~J!:I1~lfr ~XNQPS.:J;S/RATIONAI:
-------
. .: .". .:...,.. ,.. ...... ... ,::.....::. ... ." .....>."..,. .. .. .... .:'.:.. . .... ...... ... ....'.'::... .:.. .,.......... .:. ,. ., '.":":...':....'.,.,. .,..., ..':.. . .., .... ... . ..:,...... ..., ... .....
ARA~~.: ~ND:.tR:r;T~gtA~::~PY~$P~t~~,. .:"!HW.:~tP:9~~E~.E9~:, 'l'~E .~.!~BE.Tt:~":R.q!\p. .,.~~~E}:~~IN.GTON, .. .
NEW/JtAMP$HI~E:'::~':'::Y':""',:-,:'::":,:'",, '. ".. "',... ',::,;:':"::,~',::,::"":':.." . ...'
: ";." .'::: :' :. .:' :;"::' '," : H.:"',:': . "'.':.:. :.:...".. .," .'-:<.." ...':-:~::',: ./~.;,;:.:'.\:-:..'::'.': :"'.~. : '~':::..':': "".:" "::"
ACTION ";SPECIFI C.,. ARARs/::::,\:':;:.'.":':::':.::';::::'.. .."
REQUIREMENT
'..\ ..
e. Closure and
Post-Closure
(264.110 - 264.120;
265.110 - 265.120)
(Subpart G)
f. containers
(264.170 - 264.178;
265.170 - 265.177)
(Subpart I)
g. Tanks (264.190
- 264.199; 265.190
- .265.201) (Subpart
J)
h. Incinerators
(264.340 - 264.999;
265.340 - 265.369)
(Subpart 0)
2. Resource
Conservation and
Recovery Act (SWDA)
section 3020
3. Health Effects
Assessments (HEAs)
(ECAOCIN, USEPA,
March 1987)
STATUS.
. .. .. .
... . .......::.. ... ..,:,::':..
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Applicable
~o Be
Considered
..
... .
. . . ..
~EQUIR~MENT SYN6p~IS/RATION.AtE
.. .. . .. .c,:'::.:.:." :..... ... ,. . . .
Remedial action will attain the substantive
portions of the closure and post-closure
regulations.
Remedial action may include containerizing and
off-site transport of contaminated soil and/or
ground water.
Remedial action includes on-site water treatment
involving surface tanks.
Air emissions treated by catalytic converters
will attain relevant standards in this
regulation.
section 3020(b) sets out the conditions under
which treated groundwater may be re-injected to
an aquifer. The remedy will attain these
standards.
Remedial action includes ground water recharge.
-------
. . .. . .
.... . .... ,. ... ...,
. . . . """". '. . ..... ...
. .. ...... ... ....., .... '...
. . ...... ,....... "". . .
ARA~s ..ANDCRITE:RIAj..
NEW HAMPSHIRE ................ .
ACTION-SPECIFld.. ARARsi.......
., .. . . . ..,
. . .. , ,
REQUI~EMENT . ......... ........ .... 51'1\'1'1'.15..
. . ". ,. . '. ...
. . .. ..., .... . .,... .. " . .. ... . ,... . .... . ... . ',....,. . .
... ,... .... .. . ...,., . ....., ....,...... "'... . ......, '.. . .... .. .. ...
", P",. ,'''.'.., ,'.",'.."'." .", .'''.'.''..,'..,', . '..'.."'. '.', ','.'.'.'.'..'" . ., ,.. ....,.. ......... ...., ,...... .. '... . ....., '.
AP,,:tS6R~E~i. .A~I)..GUI6A.NC~FOIrTHEt~~~E.....TH .. T~H R9AD$:rTE{ ~ARRIN(;'£9N,
, .., .. . .':: :-:':'" : ,; .::-...:,:...'::::--' .... . '. ':-::::
.. . ... . . H.. ..,... .. . . ... .. .. .. .H
H~.., ..
... . ........
R.~QuiIU~;~E:N1'. SYNorSIS/RAT~9Nl\tE
..
....:...........
4. Health
Advisories, EPA
Office of Drinking
Water, March 31,
1987
5. SDWA (42 USC
300(f) et seq.;
Underground
Injection Control
Regulations (40 CFR
144, 145, 146, and
147)
6. Clean Air Act
(42 USC 7401):
a. National
Ambient Air Quality
standards (NAAQS)
for Seven Criteria
Pollutants (40 CFR
Part 50)
:.. .;..
To Be
Considered
Applicable
Relevant and
Appropriate
H...
Remedial action includes ground water recharge.
Underground injection will not result in
contamination of an underground source of
drinking water in excess of MCLs. Substantive
portions of the construction, operating and
monitoring requirements of these regulations will
be attained.
Remedial action includes air emissions control to
attain NAAQS in accordance with State
regulations.
-------
:.....", ":.: ':"":'.. .,:",::, ,.,. " ':: "','. ,....::..':::.:' ':;.:.':,:, ':'-':'::"'''' ". :';" n":::' :'..:,:': :..:',:"n "':.':"':':,:;':. "':::::"-":'" . ",':.', :,.:,;,.<_.:., '."'. '" .: ":',..:'::::.: '......'.',.'" , .'. ,,'.':.' ":".,,,:,: ' ,
. ARAijs:..'. AND' . CRir:rF;J{i.Ai:..~PY:J;~O~~f;$~':A1;t.9~4 ~g~,SE,r(:)R..: t.~~,u!t ~,~E:~r.~.~9~r)r~!!.~;r~~INgr:r6~).......
. NEW.-'.HAMPSHIRE..:'..'.""""-:"'..."::O"'/.,. u'.'."'.. ........' '.'.:"'::..u.. u... . . ..u ....
. .
. . .
R~QVIRJ::~ENT.
. . .
... . ., .. . ,-.. .,..
, .. """" ..,. ,-, ...
, , " ,....,..,.",........ ...,..,
ACT:iONisPECIFlq:',~Ri\~~::::;:::'::':':'::::.::)::::: . .
.. .
"', .' ., .
" ..
.. .. ,
:~1%~1g~
b. National
Emissions standards
for Hazardous Air
Pollutants (40 CFR
Part 61)
7. OSWER Directive
9355.0-28
8. U.S. EPA Region
memo - July 12,
1989 Louis Gitto to
Merrill Hohman
9. EPA' s Ground
Water Protection
strategy Guidelines
for Groundwater
Classification
,..,..
Relevant and
Appropriate
To Be
Considered
To Be
Considered
To Be
Considered
.
.. .
,. .. .. ... ..
., ,... " .,. . . , .
.... .. ..,.. .
:f 'iN9P~JS.!~T*Rff~~E;
. .
..
Remedial action includes air emissions controls
to attain these standards.
This guidance on the control of air emissions
from air strippers will be considered in the
design and operation of the vapor extraction and
groundwater treatment system.
This memo sets forth Region I policy, that in
areas not attaining the National Ambient Air
Quality Standards for ozone, air strippers used
in CERCLA response actions will be subject to
.controls on VOC emissions.
Remedial actions will consider ground water
classes.
-------
. '. . .
. .. ""'" ""'" .. ,. .... . .. .. ..",
.. '..' '..'...'. '..".. ""'.. . ".' .,. .,'.'.'.'.'.,.' '.. .. ... . '. ... .. .. "'..
AMRs AND.CRITERIA( A[)VISORtES'~() GtJIJ)f\NCEFOg'J:'H~T:tI3BETTS..PROA()pSITEi .BARRINGTON ~
NEW HAMPSHIRE. . .. ... ..... ... . .. ....
.
ACTION;"SPECIFIC ARARs
REQUIREMENT
.....
. ... ... .
..STATUSp
10. Proposed
Standards for
Contaminant
Emissions of
Volatile Organics
(50 FR 3748-2/5/87)
...stct€~\d f.'N~~H6ffi~~hir~'.::~~4ijii~ili~6€$r"
1. NH Hazardous
Waste Management
Law RSA 147A
2. NH Groundwater
Protection Act, RSA
485C
3. New Hampshire
Hazardous Waste
Rules, Subtitles
Env-Wm 500 and 700
To Be
Considered
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
. . .
.... .
, .
.. ..
R~QU:rR~ME:NT S'iNOPSIS/R1\T:i;ONALE
.... .:..
This proposed regulation will be considered in
the design of air emission controls.
.
'.".."'.'
'.'.....".... ...
p
These standards pertain to the treatment,
storage, transport and disposal of hazardous
wastes. Because hazardous substances found at
the site ar~ sufficiently similar, this statute
is relevant and appropriate to portions of the
remdial action. In particular, standards
relating to storage, transportation, and land
disposal of hazardous wastes will be attained.
These standards pertain to ground water
classification, prohibited uses with areas of
primary uses of ground water, and mandate best
management practices concerning potential
contamination sources.
Standards pertain to treatment, storage and
disposal of hazardous waste and closure of
hazardous waste facilities. See section Env-Wm
211. 01.
-------
AIDili~:A~'t{BRi~g~fA'::::1\'DvIs6R:i~s::: AN6:GhIDAN6E!'f9R"~HE':,':T1'B~EfT~..'~oAD.'. SiT~>B~~iNGTON , '.
NEW(HAMPSHIREi' :::J:q:::q ':;':='.. .. . . '..". ..
ACT:I:ON~SPECIinC:ARARS":: ~ q...
. . '...:<" .
~~?Y.~R~~~NT.,q:i ",'q STATUS.
'.: :...:... .. :.:." . .. '.'. ::....."...:...:::.::.'.. . ..
a. Requirements
for Hazardous Waste
Generators Chapter
Env-Wm 500
b. Requirements
for Owners and
Operators of
Hazardous Waste
Facilities NH
Hazardous Waste
Rules Chapter Env.-
Wm 700
(i) Public
Notification Plan,
section Env-Wm
702.06
(ii) Environmental
and Health
Requirements Env-Wm
702.08
(iii) General
Design Requirements
Env-Wm 702.09
R~QUI~~~~~T:SYNOPSIS/RA'rIONl\LE
'.<....:
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Remedial action includes the generation of
treatment residuals which may constitute
hazardous waste. Substantive portions of this
ARAR will be attained during remedial action.
The remedy will meet substantive portions of this
ARAR, which regulates all contiguous land and
structures used for treating, storing or
hazardous wastes. Env-Wm 105.01(b)(a)(1).
A public notification plan to inform the public
of facility activities will be developed if
appropriate.
Remedial action will meet surface water
standards, air emission limits, OSHA standards,
and prevent exposure of hazardous elements to
humans and the environment.
Facilities shall be designed and operated to
control fugitive dust, divert and collect surface
run-off, and be located above the 100 year flood
level.
-------
.. '.. . ... '.. .'
. ... .. . . ... .. .... . .... . ..,. ..... . . .. .
. ". ." .'.' ".""" ... '..'.'... . ..,..'. . .'. '.'. .'.. '.'.'.".. ... ',' '...' ,.. "'. .. . .. ".. .... .. ... .., .'.' ,".' ,
. ARAR$ .... ANDCRI'rERtA ~... i\QYIS6Jt1;E$;ANDGU:rDAN<::EqFORTHETIBB~TTSR9~[) SI.TE ~...... J3A~ntGTON ,
NEW. HAMPSItIRE.. . ...... .... ..... .
... , ... ,
. '...", .. .
REQUIREMENT.
(iv) Ground Water
Monitoring Env-Wm
702.11, 707.02(i)
(v) other
Monitoring Env-Wm
702.12
(vi)
Emergency/Remedial
Actions Part Env-Wm
706
(vii) Security
Requirements, Env-
Wm 707.02(c),
708.02(c)
incorporating by
reference 40 CFR
~264.14
. ..' ....,... ..
. . . .
.. .. "".'. .. ..
S~A'1;U~>
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
.. .
. . ""'"
.... ., """
........ ""'. ....... .
... . .... . .
SYNOPSIS/.RATIONALE ....
.";,..' . ..'.';";:,:::"';';;",,,"'-".'-;;":-......:...;;.';..:.':-,';'.':-:-.'.:
Remedial action will include area ground water
monitoring to track plume migration.
Appropriate monitoring systems, including air
emissions and surface water contamination, will
be installed as appropriate in compliance with
this ARAR.
Remedial action shall include an emergency
contingency plan in the event of an accidental
release of hazardous constituents that may
endanger or threaten public health or the
environment.
Remedial action will include excavation of
contaminated soil and on-site treatment of
contaminated ground water; access control would
be necessary to protect public from exposure to
hazardous constituents. .
-------
.'.';.: : "::;':,;'::"::';':' ':. ::.."". .. . :""";:-:':::"" .;.:'..' "'::" ....:':": ::":':::"::';"::':::-":':"'" .:::'.'..'...'::.... ':':'. '...' ':'.'. .. '.:'.:':' ':'. :.' .... ..:::..:.': .:......'..:.. .'.." .:... ...' ,-:.,"'...' :'. .:.:'.": ":.":',;':,:?:',:-;",""':.' :-. .:':.
ARAijs.:'ANb.: 'GRt~~~1..A'f: ~PYl$.qR~~.~,.:~.!tP~V:tP~~A:~:f9.ifr~E ;t~~~E~':['~:.'RQA[j:J f~~, Jj~I~C;TON ;
NE\'t.HAMPSIURE' ..".'.. :'.":.'.. H H' H
: :.. '.' .' . '. .,: :...:;. .::::.:..: : ;:: ... ':.C..H. H
ACTION~SPECIFIC: A.RARs: '.."
. ...
. .
:.. ... :
.'.:..-....'...:...:.:.::..::.:::..:..::.;...::/"..:.:
.. .
..
'H
..':.:H.H .H. ... :: C... ...... '. c. '. . '... . ... .. . '.'
~~QUIRE~ENT SYNOP'SIS/RA~IONALE
H".: ,"':'..<......" ....:' H '." .. . ..
Remedial action includes storage, treatment, or
disposal of hazardous waste
on-site; facility operation requires personnel
training to ensure compliance with applicable
standards and effective emergency response.
REQQIREMEN'f
.. . .
HH '$.TAr;r,y~.
: ..:;.:.: ..:.. ..;:.. :..;"'" . ...:.H:'::';H..<.. ..
(vii) General
Inspection
Requirements Env-Wm
707.02(d),
70a.02(d)
incorporation 40
CFR ~265.16
(x) Preparedness
and Prevention
Requirements, Env-
Wm 707.02(g),
70a.02(h)
incorporating 40
CFR 264, Subpart C
(xi) contingency
plan, Env-Wm
707.02(g) ,
70a.02(h)
incorporating 40
CFR 264, Subpart D
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Remedial action includes storage and/or treatment
of contaminated soil or ground water; and may
require appropriate measures to prevent and
respond to any unplanned release of hazardous
waste constituents.
Remedial action includes storage and/or treatment
of contaminated soil or ground water; and may
require appropriate measures to prevent and
respond to any unplanned release of hazardous
waste constituents.
-------
. .... .. . . ".' .. . ... .. . . . ". .. . .
. '... ... '.'.''''. ... ..... .. .. .... .. .. .... ..... .. . .... . . . .... .... . . . ......... ... .. .
. .. . ... . .... .... . . . ...... . ... ... . ..... ... .. ... . .. . ... .. .. .... ..... ... .. ... .... ..... ... . .. ..... . ... . .. .
.. .. ... ..... . .. ...... .... . . .. ",..,.""."""".,.." ..'.' ......................... . ................ ... . ... ..... ...... ..... ...... . . ..
.. ..... . . .. ... .. ........... .. ... ... .. ... .. .. . . ............. .... '."'.'... ... .. ......... .. ..... "".,." ... ..... . '..' .. ..
ARARs .. ANifdnTER.~A ~...p~PV:I.~6~:t#.~i~DGt);~~c~if()j{(tHE:.r.rtBBE.:'1't$R~~p$!1'Erij3zumINGTON, .
NEW HAMPSHIREP
. ... .. .
. . ..
. .. ..... . .
ACT1oN-SPECIFICARARS/
(xii) Closure and
Post-Closure, Env-
Wm 707.02(j),
708.02(k)
incorporating 40
CFR Subpart G
(xiii) Technical
Standards for
container
Management, Env-Wm
707.03(a),
708..03(d) (1)
incorporating 40
CFR Subpart I
(xiv) Technical
Standards for Tanks
Env-Wm 707.3(b),
708.03 (d) (2) 40
CFR Subpart J
(xv) Incinerator
Standards, Env-Wm
707.03(g),
708.03(d) (7)
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Remedial action will attain substantive portions
of closure and post-closure requirements.
Remedial action may include containerizing and
off-site transport of contaminated ground water
and/or treatment residuals. .
Remedial action includes on-site water treatment
involving surface tanks.
Air emissions treated by catalytic converters
will attain relevant standards in this
regulation.
-------
:.'.,." ::,,",,:""::::':;::'H' . ",,':"""""':' '-. ,.'<. :':::::::,,::::..,:..:'" .': ,':>': :"",:',"':-:- .:: ;;:::::':'::"':" ,': ':.' .: ',' ::" '. .- ,'.':, .:. '" ,,".u' ,', ,":, ". ' .. ',. '.', ' ,'., . ", ,::,. '.' ".';::: . - , .
ARARs..A~D :CRIT~~~:.A.~i;:~9.yt~o~t~S~:ANDGtJIDl\NCE . rORTHE. TIBBETTS. ROADSIT~ '::~ARRlttGT6N, .
NEW.:" HAMPSHIRE :\: .::.::::'.::..:i ..:;.:.,:: .. .. ...<:-,.. .: ,.:".....
..
:... ..
ACTION-:~PECIFI9~RARS>: .,: ..::::.i:.: .:.<
, '.: '."',, ":.,' .: :,~ ' . , ' : ; " ."
,. ,.." .. .. " . H , ... ..
. REQtJ~ RE.~~~~ , ,.:i> H ".:ST A.iJ'4s
. : .., :..::. .:.,. .:. .. :.. .. '. . H':;.,:/:.;:: ."...::::: :.. .H .... .....
5. RSA 125-C:4, I
NH Admin. Code
Chapter Air 300,
Air Quality
standards
6. RSA125-C:6, XI
NH Admin. Code
Chapter Air 800,
Testing and
Monitoring
Procedure
7. RSA 125-C:6, XI
B:NH Admin. Code
Chapter Air 900,
Owner or Operator
obligations
8. RSA 125-1:3, NH
Admin. Code Chapter
Air 1204, Volatile
Organic Compounds
9. RSA 125-1:3, NH
Admin. Code Ch.
1301, Tox. Air
Pollutants
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
Relevant and
Appropriate
..
.....
.;::-:::i::
...
.~~q4J:8~b.~ktpyijq~s!~/M~i6~A~E
H
The selected remedy will include air emission
controls to ensure that AAQSes are not exceeded,
including use of Lowest Achievable Emissions Rate
(LAER) for ozone.
The selected remedy will comply with the
substantive portions of this regulation.
The selected remedy will comply with the
substantive portions of this regulation.
The selected remedy will include emission
controls that meet the relevant and appropriate
requirements of this regulation.
The selected remedy will include emission
controls that meet the substantive requirements
of this regulation.
-------
,,' .., , "..' , .. ,......, , " '" ",.., "" .., ,.., , ".. ..' ..,.., ..,.... ,...., , ,.." ,..', ,.., ,...., ' ,
',', ",' ',', '",',',',,',', ',', ,',', ,',',',', ,'" ,,','" ,",',',' ',,",'.', ",",'"", ,',',',',",'"',',',',, ,',",',,',',', ',",','", "',,',,, ,',', '" ,,"'" """"'" "" " '""','""""'",'"',,',',',',,,,,, ,",'" ,',',',',',,',',",",',',,',',,"',' ,,',",',,',',',', ",,',',,' '"""" ,', "",,
.., ....,.., ",.., .., ..' ....,..,.." ......",.... ",..,..,.., ..,....,.." ......,.. ..",.. .... ......' ,.., ,.. " , .." " " , .., ,......, ,...., .. ..'..',......' .., '.. '.., "..
ARARS~ANh:CR~1:~Rf~~<~riY~$O~iE~~.Atip.~4~6l\~~~ FQRTHETIB~E:TT$.R6~g~:I:~~;~A.RrtINGTON, ..
NEW HAMPstURE./H . .
. ..
. H
, ' , ,
, " ,
REQUIREM~NT
. . .
'" ...., , '
, , .., ,.. ..
, , ' '
.... ",...., '.., ".. , '" '" ..,
~~qUI~~~~ff'J,'..H~¥NqR~+$./~t:.c9Nl}L#H
10. NH Admin.
Code, Part Env-Wm
604, Abandonment of
Wells
Applicable
Abandoned wells will be sealed in a manner
preventing entry of contaminants into ground
water in accordance with this rule.
-------
~~ES.
Sbte of New Hampshire
DEPARTMENT OF E~",'IROm-~-rAL SER'lCES
5 Hazen Drive. P.O. Box 95. Concord, I'I11 03302-0095
603-271-3503 FAX 603-271-28157
September 23, 1992
~.~.o
$~~
//~. - <\~.:1~.'~
(.:~ :fI" 1 - ~\~\
.~...... . !.;;':1
l~:~ ~:~:,
\.~; ,.zu.:."J
'~~~'i
~
-
-
TDO ..I,c~:!: Rei,',}' :'i'ti 1.500-735.Z964
Mr. Merrill S. Hohman
Director, Waste Management Division
US Environmental Protection Agency
JFK Federal Building
Boston. MA 02203
Re:
Record 01 Decision
Tibbetts Road Site
BarrlngtonrNH
Dear Mr. Hohman:
The New Hampshire Department of Environmental Services (DES), af"iif1g ~~ <:I.ytlf It
for the State of New Hampshire, has reviewed the Record of Decision (ROD) for the
Tibbetts Road Site and concludes that the recommended remedy.is consistent with the
rules and regulations 01 applicable or relevant and appropriate state requirements. The
recommended remedy utilizes a pump and treat system to reduce contaminant levels in
the ground water and gradient contrul tu rt:ltC,ird the migration of the contaminant plume.
If the Trust Fund is used and state funds are available, the State agrees to provide it's
matching share.
The State understands the recommended remedy provides for the continued
operation of thtl Swains Lake ViHage Water System and the connection of additional
residences to that system for the purpose 01 gradient control. The State concurs that
replacement of private water supply wells with a public water supply provides gradient
control and, as such, constitutes remedial action as defined in the National Contingency
Plan (NCP) and relevant and appropriate state law.
Sincerely,
q~:::O~'
rhilip J. O'Brien, p~'
Director
Waste Management Division
P JO/GWB/mjc/RodTbts. Doc
Cl~; Oaniel Coughlin. P.L, USEPA
Darryl Luee, USEPA .
Carl W. Baxter, P.E.. NHDES-WMEB
Leslie Ludtke, Esq., NHDOJ
AIR RESOt:RC'E5 D!V
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