United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
E PA/ROD/R01 -88/032
September 1988
&EPA
Superfund
Record of Decision
Landfill & Resource Recovery, Rl
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30277-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R01-88/032
3. Recipient's Accession No.
4. Titl* and Subtitle
SUPERFUND RECORD OF DECISION
Lcandfill & Resource Recovery, RI
•FjjisJi Remedial Action - Final
^. Auth
5. Report Oitt
09/29/88
7. Author<»)
8. Performing Organimation Rapt. No.
9. Performing Organization Nam* and Address
10. Project/Task/Work Unit No.
11. Contract(C) or Grant(G) No.
(G)
12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Typ* of Report & Period Covered
800/000
14.
IS. Supplementary Notes
16. Abstract (Limit: 200 words)
The Landfill & Resource Recovery (L&RR) site is located in North Smithfield, Rhode
Island, and consists of a 28-acre landfill and a sand and gravel pit. Several unnamed
streams lie to the south and east of the site and flow through wetlands located .adjacent
to the site area. Several homes near the site use ground water for drinking, and the
Statesville reservoir, used for recreational activities, is located approximately
0.5 mile from the site. The L&RR site is a former sand and gravel pit that began
ccepting domestic, commercial, and industrial wastes in 1927. Site owners claim the
hazardous materials were mixed in with municipal refuse and deposited in the
north-central area of the site, but other reports indicate hazardous waste was spread
over the entire site area. When hazardous waste disposal ceased in 1979 the owners
placed a PVC cover over the north-central area to prevent stormwater infiltration.
Commercial and domestic wastes were disposed of on top of and around the area in
subsequent years. In 1983, the Rhode Island Department of Health installed monitoring
wells onsite to ensure compliance with State regulations, and based on sampling results,
ordered the site closed. Upon final closure in 1985 the owners covered 80 percent of
the landfill area with one foot of sand, another synthetic cover and topsoil. Eighteen
gas vents'were installed to vent gases underlying the synthetic cover. The sand used as
(See Attached Sheet)
17. Document Analysis a. Descriptors
Record of Decision
Landfill & Resource Recovery, RI
First Remedial Action - Final
Contaminated Media: air
Key Contaminants: hydrogen sulfide, methane, VOCs (benzene, PCE, TCE, toluene)
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
154
22. Price
(SeeANSI-Z39.18)
See Instructions on Reverie
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
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EPA/ROD/RO1-88/032
Landfill & Resource Recovery, RI
pirst Remedial Action - Final
16. ABSTRACT (continued)
final cover has eroded into the adjacent wetlands, but sampling indicated no
contamination was present. Low levels of VOCs and metals including lead, cadmium, and
arsenic were discovered in downgradient ground water samples, but levels were sporatic
and all were below MCLs. This remedial action will upgrade the existing landfill
enclosure ho protect ground water and wetlands, implement wetlands recovery operations,
and collect and treat landfill gas to reduce risks to public health from inhalation.
Primary contaminants of concern affecting the air are hydrogen sulfide and methane gases
contaminated with VOCs including benzene, toluene, PCE, and TCE.
The selected remedial action for this site includes: access restrictions;
stabilization of the steep side slopes of the landfill and installation of a RCRA cap
over the entire landfill, with revegetation; collection and thermal destruction of
underlying gases, the method of thermal destruction to be determined in design;
excavation of eroded landfill sand from the wetlands, with replacement onsite, and
vegetation of excavated wetland areas; and ground water and air monitoring. The
estimated present worth cost of the selected remedy is between $5,674,000 and
$6,790,000, depending on the particular method of slope remediation and thermal
destruction chosen. O&M costs were not provided.
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
"EOIONI
J.F. KENNEDY FEDERAL BUILDING, BOSTON, MASSACHUSETTS 02203-2211
RECORD OF DECISION
Landfill t Resource Recovery (LSRR) Site
Horth Smithfield, Rhode Island
8TATEXEHT OF PURPOSE
This Decision Document represents tbe selected remedial action
for the Landfill i Resource Recovery (LiRR) Site developed in
accordance vith the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 (CERCLA), as amended toy
the Superfund Amendments and Reauthorization Act of 1986 (SARA)/
and to the extent practicable, the National Contingency Plan
(KCP) 40 CFR Part 300 et sea.. 47 Federal Register 31180
(July 16, 1982), as amended. The Region I Administrator has been
delegated the authority to approve this.Record of Decision.
The state of Rhode Island has concurred vith the components of
the selected remedy vhich are consistent vith the 1983 court
Order and Consent Agreement between the Rhode Island Department
of Environmental Management (RIDEM) and Landfill & Resource
Recovery (LiRR), Inc. In regards to the additional requirements
established by EPA, the State of Rhode Island recognizes that
these requirements are not inconsistent vith the 1983 Court Order
and provide additional protection. The State of Rhode,Island has
also determined, through a detailed evaluation, that the
selected remedy is consistent vith Rhode Island lavs and
regulations.
8TATEHBBT OF BASIS
This decision is based on the administrative record vhich vas
developed in accordance vith Section 113(X) of CERCLA and vhich
is available for public reviev at the Korth Smithfield Municipal
Annex Building and the EPA Region I Waste Management Division
Records Center in Boston. The attached index identifies the
items vhich comprise the administrative record upon vhich the
selection of the remedial action is based.
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or m SELECTED REMEDY
Tbe selected remedy ha* four major components vbieb togetber form
• eomprebensivo approacb to Site remediation.
•
1. Upgrading tbe Landfill closure
• *
Tb« •sitting landfill closure will be upgraded to protect tbo
groundvater, to protect tbe vetlands and to meet ARARs.
Upgrading tbe landfill closure includes installing a fence;
developing a post-closure monitoring plan; upgrading tbe surface
vater runoff management system; stabilising tbe stoop sido slopes
and installing a syntbetio eover on tbo uncovered nortbeast area
of tbe landfill; estafelisbing a cover tbiokness of 24 inebesi and
establisbing vegetation. Tbe syntbetio cover vill proteet tbe
groundvater fej minimising infiltration. Upgrading tbe existing
surface v&tex management system, stabilising tbe steep'side
slopes and establisbing vegetation vill protect tbe vetlands'by
minimising erosion. All of tbe components contribute to tbe
remedy attaining JUftARs.
Two alternatives bave been selected for stabilising tbe steep
slopes. Tbe specific alternative vill be selected during tbe
design pbase of tbe remedial action after slope stability tests
are conducted.
2. Qmm Collection and Tbermal Destruction
Tbe landfill gas vill be treated to reduce tbe potential risks to
public bealtb from inbalation of tbe landfill vent emissions.
Tbe existing landfill vents vill be utilised to collect tbe
landfill gas. Tbese vents vill be manifolded by a subsurface
piping system vbieb vill direct tbe gaseous emissions to tbe
treatment system.
Tbree tbermal destruction tecbnologie* bave been selected to
treat tbe gaseous emissionsi combustion, flaring and
incineration. All of tbese tecbnologies burn tbe landfill gas to
destroy tbe basardous constituents. Typically, tbese
tecbnologies can destroy betveen *0% and t»% of tbe contaminants
in tbe gas tbat enters tbe system. Tbe specific technology to be
utilised for tbermal destruction vill be ebosen by EVA during tbe
design pbase after pilot tests bave been conducted to insure tbat
tbe remedy is protective.
3. Wetlands Remediation
During tbe Remedial Investigation, tvo areas of tbe vetlands vere
identified as needing remediation due to cover material erosion
and subseguent sedimentation. In tbese areas, tbe sand vbieb bas
eroded from tbe landfill vill be excavated and tbe vetlands vill
be revegetated. Since tbe eroded sand is not contaminated, tbe
excavated sediment can be redeposited on-site. To promote
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wetland revegetation, •oils similar to those of the natural
wetland will be placed, and sedges and others species vill be
planted. During revegetation, the natural contour of the
wetland vill be restored to maintain the easterly flow of the
creek toward the main wetland body. Additional areas Bay be
defined during the design phase if erosion has caused further
damage since the RI was conducted.
4. Site Monitoring
To insure that the remedy remains protective, both the
groundwater and the air will be monitored periodically for thirty
years. The existing network of wells plus one new well cluster
will be monitored on a quarterly basis for a number of
constituents that were selected based on site specific
information. The monitoring results will be reviewed on a
periodic basis to determino if a variation indicative-of a plume
is present.
The air monitoring program will depend on the specific technology
chosen for gas treatment. This plan will be outlined during the
design phase and will specify the monitoring locations, the
sampling technique, the indicator parameters and frequency of
monitoring. Depending on the technology, this plan may include
•mM ant* -a±r uruillnring and emissions testing to insure that the
system is protecting public health and the environment.
DBCL&R&TXOH
The selected remedy is protective of human health and the
environment, attains federal and state requirements that are
applicable or relevant and appropriate and is cost-effective.
This remedy partially satisfies the statutory preference for
treatment that permanently and significantly reduces the volume,
toxicity and mobility of the hazardous substances, pollutants and
contaminants, as a principal element. Finally, it is determined
that this remedy utilizes permanent solutions and alternative
treatment technologies to the maximum extent practicable.
Date' Michael R. Deland
Regional Administrator
5Z_
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LANDFILL 6 RESOURCE RECOVERY SITE
Record of Decision Summary
TABLE OF CONTENTS
Contents Pace
I. SITE NAME, LOCATION AND DESCRIPTION ...».-.... 1
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES ...... -. 4
A. Remedial History ............... 4
B. Enforcement History ............. 5
III. COMMUNITY RELATIONS ................. 6
IV. SCOPE OF RESPONSE ACTION .............. 7
V. SITE CHARACTERISTICS ............ .... 7
A. Air ...................... 7
B. Groundwater and Subsurface Soils ........ 9
C. Surface Water and Sediments .......... 11
VI. SUMMARY OF SITE RISKS ................ 11
A. Public Health Assessment ....... ..... 11
B. Environmental Assessment ....... ..... 16
VII. LANDFILL CLOSURE ASSESSMENT ............. 16
A. Evaluation of the Cover's Performance ..... 18
B. Compliance with Federal and State RCRA
Requirements .................. 19
VIII. DEVELOPMENT AND SCREENING OF ALTERNATIVES ...... 19
A. Statutory Requirements/Response Objectives ... 19
B. Technology and Alternative Development and
Initial Screening ............... 20
IX. DESCRIPTION/SUMMARY OF THE DETAILED AND COMPARATIVE
! ANALYSIS OF ALTERNATIVES .............. 24
A. Alternatives Analyzed ............. 24
B. Gas Treatment Technologies Analyzed ...... 28
X. DOCUMENTATION OF SIGNIFICANT CHANGES ........ 29
XI. THE SELECTED REMEDY ................. 29
A. Description of the Selected Remedy ..... 29
1. Upgrading the Landfill Closure ...... 29
2. Gas Collection and Thermal Destruction . . 31
3. Wetlands Remediation ........... 36
4. Site Monitoring .............. 36
B. Point of Compliance and Target Cleanup Levels . 38
C. Rationale for Selection ..... •. ...... 38
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LANDFILL & RESOURCE RECOVERY SITE
Record of Decision Summary
TABLE OF CONTENTS
Contents Page
XII. STATUTORY DETERMINATIONS 39
A. The Selected Remedy is Protective of Human
Health and the Environment 39
B. The Selected Remedy Attains ARARs 40
C. The Selected Remedial Action is Cost Effective . 42
D. The Selected Remedy Utilizes Permanent
Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies
to the Maximum Extent Practicable 52
E. The Selected Remedy Partially Satisfies the
Preference for Treatment as a Principal Element . 52
XIII. STATE ROLE 53
LIST OF FIGURES
Figure Number . Page Number
Figure 1-1: Site Location Map ..... 2
Figure 1-2: Site Layout Plan 3
Figure V-l: Location of Landfill Vents 8
Figure V-2: Monitoring Well Locations 10
Figure V-3: Surface Water and Sediment Locations 12
Figure VI-l: Wetland Community Section 17
Figure XI-1: Comparison of'Slope Stabilization Techniques . . 32
Figure XI-2: Alternative 3 33
Figure XI-3: Alternative 4 34
Figure XI-4: Wetlands Remediation 37
LIST OF TABLES
Tftbl? Number Page Number
Table VI-l: Contaminants of Concern . 13
Table VI-2: Summary of Exposure Routes 14
Table VTII-1: Alternatives Developed for L&RR Site ..... 22
Table XII-1: Location-Specific ARARs 43
Table XII-2: Chemical-Specific ARARs 46
Table XII-3: Action-Specific ARARs 48
APPENDICES ;
^
Responsiveness-Summary .... Appendix A
Administrative Record Index Appendix B
State Concurrence Letter Appendix C
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ROD DECISION SUMMARY page 1
Landfill & Resource Recovery Site
I. SITE NAME, LOCATION AND DESCRIPTION
The Landfill and Resource Recovery.(L&RR) Site ("the Site") is a
closed landfill in the Town of North Smithfield, Rhode! Island
that historically received domestic, commercial and industrial
wastes. The landfill covers approximately 28 acres of a 36 acre
parcel of land owned by Landfill and Resource Recovery (L&RR),
Inc. The Site is located on Oxford Turnpike, northwest of Pound
Hill Road (see Figure 1-1: Site Location Map).
The landfilled area extends from the edge of Oxford Turnpike on
the west, to within 50 feet of the property line on the north and
east, and to within 100 feet of an intermittent unnamed stream on
the south. The Site is located in a rural area primarily
surrounded by woodlands. A sand and gravel pit exists south of
the landfill, on property also owned by L&RR, Inc. Three unnamed
streams exist south and east of the Site. These streams flow
through wetlands, also located south and east of the Site, and
discharge into Trout Brook. Trout Brook flows north for about
2000 feet to Trout Brook Pond which discharges into the
Slatersville Reservoir. The Slatersville Reservoir and Trout
Brook are Class B water bodies suitable for fishing, swimming and
other recreational purposes.
There are several homes near the landfill that have private wells
and use groundwater as a source of drinking water. These homes
are located on Oxford Turnpike, Pound Hill Road and other nearby
roads. The closest residence is approximately 1200 feet
southeast of the landfill, on Pound Hill Road (see Figure 1-2:
Site Layout Plan). The landfill is located over the
Slatersville Aquifer which has been designated as a drinking
water source by the State of Rhode Island.
The Site is a former sand and gravel pit that reportedly began
accepting wastes for disposal around 1927. The Site owners claim
that the hazardous materials were co-disposed with the municipal
wastes in the north-central area of the Site, other reports
received by EPA have stated that the hazardous waste were co-
disposed with municipal wastes throughout the Site.
Consequently, EPA does not know the full areal extent of
historical hazardous waste disposal. When hazardous waste
disposal ceased, the so called "hazardous waste area", as
defined by the owners, was covered with a synthetic cover made of
20-mil poly vinyl chloride (PVC). This action was conducted by a
company under contract to L&RR, Inc., and was intended to reduce
infiltration of rain and melted snow into the waste. After this
action, the landfill continued operation placing'commercial and
domestic waste on top of and around this area. When the landfill
was closed by the owner, the landfill was graded and covered with
approximately a foot of sand and another synthetic cover. This
synthetic cover was placed over approximately 80% of the
landfill. Additional soil was placed on this cover to establish
vegetation. The side slopes are steep, ranging from slopes of
3:1 to slopes of 2:1.
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page 2
APPROXIMATE LOCATION
ESTERN SAND ANC
. ft. I.. TJ HIMfft '
SITE LOCATION MAP
L & RR SITE
NORTH SMITHF1ELD, RHODE ISLAND
M1t-O1
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Figure 1-2
Site Layout Plan
page 3
—. . — Property Une
nnnnrr Access Road
Tributaries
Residences
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ROD DECISION SUMMARY page 4
l & Resource Recoverv Site
The landfill contains 18 landfill gas vents which were
constructed to vent gases from below the synthetic cap and soil
that cover most of the landfill. Gas is generated from decaying
wastes disposed in the landfill. These vents are installed at
varying depths throughout the top of the landfill and -are
currently closed to prevent gases from being released.
Surrounding the landfill is a fence which consists of strands of
barbed wire attached to wooden posts. This fence is similar to
those used to restrain cattle and horses.
A more complete description of the Site can be found in the
Remedial Investigation/Feasibility Study (RI/FS) Report on pages
2-1 through 2-7.
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Site was originally a sand and gravel pit that reportedly
began accepting wastes for disposal around 1927. In 1969, the
Site began operation as a solid waste disposal area under the
management of Harvey Fortune. This operation was sold to L&RR,
Inc., in 1974. A Solid Waste Management Tacility licence was
issued to L&RR, Inc., by the State of Rhode Island in December
1976. In November 1977, L&RR, Inc., submitted plans for
installing 7 monitoring wells to the Rhode Island Department of
Health (RIDOH). These wells were installed to comply with State
regulations pertaining to hazardous waste disposal. This
submittal was the first indication that hazardous waste disposal
was occurring at the Site. In September 1979, Rhode Island
Department of Environmental Management (RIDEM) ordered L&RR,
Inc., to cease accepting hazardous waste. In December 1979, the
hazardous waste area, as defined by L&RR, Inc., was covered with
a synthetic cover. Additional landfilling of commercial and
domestic waste over and around the covered area continued until
1985. Landfill closure began in 1985 pursuant to a 1983 Court
Order and Consent Order and Agreement ("the 1983 Court Order")
between RIDEM and L&RR, Inc. To date, most of the closure as
required by the 1983 Court Order has been completed.
A. Remedial History
The L&RR Site has been the focus of several investigations by
the Environmental Protection Agency (EPA), the Rhode Island
Department of Environmental Management (RIDEM) and the owners
since 1977. Between 1977 and 1980, several sets of monitoring
wells were installed and sampled on an irregular, basis. Between
1980 and 1981, the EPA conducted a Preliminary Site Assessment
of the L&RR Site which resulted in the Site being ranked on the
National Priorities List (NPL) in 1982. A Remedial Action Master
Plan (RAMP) was completed for the Site in 1983. The RAMP
evaluated existing data sources, identified data needs and
recommended remedial action activities. In 1985, L&RR, Inc.,
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ROD DECISION SUMMARY page 5
Landfill & Resource Recovery Site
began to close the landfill under a Court Order and Consent Order
and Agreement with RIDEM. EPA was not a party to that Court
Order and began a federally funded RI/FS in May 1986. A more
detailed description of the Site history can be found in the
RI/FS Report on pages 1-3 through 1-9.
B. Enforcement History
A number of enforcement actions have been taken against L&RR,
Inc., by RIDEM. On September 6, 1979, RIDEM ordered L&RR, Inc.,
to cease accepting and disposing hazardous wastes. The landfill
continued accepting commercial and domestic wastes. On December
1, 1980, the L&RR Solid Waste Management Facility license was up
for renewal. L&RR, Inc., filed a renewal application and
continued operation. On October 30, 1981, RIDEM ordered L&RR,
Inc., to cease accepting all wastes and to close the northern
section of the landfill where the hazardous waste was allegedly
disposed. On November 9, 1981, L&RR ceased operating for a three
week period and appealed the RIDEM order. On December 28, 1981,
the RI Superior Court issued an order staying the enforcement and
effect of the RIDEM order and allowing the landfill to continue
operating. Based on new monitoring information, RIDEM issued
another order to close the landfill. In January 1982, the RI
Superior Court found RIDEM in contempt of the December 28 order
and allowed L&RR to continue operations. On July 13, 1983, RIDEM
and L&RR, Inc., entered into a Consent Order and Agreement which
set forth terms and conditions governing the continued operation
and eventual closure of the landfill. This Consent Order and
Agreement was approved by the Superior Court for the State of
Rhode Island and is referred to'in the remainder of this document
as "the 1983 Court Order." The landfill ceased operating in
January 1985.
In June 1983, L&RR, Inc., requested that EPA accept the reports
and plans developed under the 1983 Court Order as fulfilling the
requirements of an RI/FS. EPA reviewed and commented on the
1983 Court Order and plans but did not accept them as fulfilling
the requirements of an RI/FS consistent with the National
Contingency Plan (NCP). Consequently, during 1983 and 1984, EPA
conducted numerous negotiations with L&RR, Inc. As a result of
these negotiations, EPA sent L&RR, Inc., a proposed consent order
on November 24, 1984 for concurrence. This consent order would
have allowed L&RR, Inc., to submit the data collected under the
1983 Court Order supplemented by additional investigations and
studies required by EPA to fulfill the requirements of an RI/FS
consistent with the NCP. L&RR, Inc., failed to respond and
concur with EPA's proposed consent order. On January 29, 1985,
EPA notified L&RR, Inc., that the Agency was withdrawing from the
process of negotiating a formal agreement with L&RR, Inc.,
regarding the RI/FS.
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ROD DECISION SUMMARY page 6
Landfill ft Resource Recovery Si tie
On June 5, 1986, EPA notified L&RR, Inc., of their potential
liability with respect to the Site. On July 29, 1988, EPA sent a
notice letter to L&RR, Inc., which .formally demanded
reimbursement for past costs; requested information regarding
activities at the Site; and, requested voluntary participation in
undertaking forthcoming remedial activities.
On July 29, 1988, EPA also notified additional parties 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. EPA expects to carry out negotiations with the PRPs for
conducting the remedial activities.
EPA's formal comment period on the Proposed Plan, which
describes EPA's preferred remedy as well as the other
alternatives considered for the Site in the FS, was from July 20
through September 2, 1988. An extended comment period, six weeks
rather than the required three weeks, was held to allow
additional time for the Potentially Responsible Parties (PRPs) to
participate in the remedy selection process. Comments presented
by the PRPs during the public comment period are included in the
Administrative Record. A summary of these comments as well as
EPA's response, which describes how these comments affected the
remedy selection, are included in the Responsiveness Summary in
this document.
III. COMMUNITY RELATIONS
Throughout the Site's history, community concern and involvement
has been moderate to high. The community was- particularly active
in the late 70's and early 80's and repeatedly sought to close
the landfill. Other concerns expressed by the community include
contamination of the Slatersville Aquifer; development, growth
and property values in the community; and, potential health
effects caused by exposure to 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.
In 1983, EPA released a community relations plan which outlined a
program to address community concerns and keep citizens informed
about and involved in remedial activities. This plan was revised
in October 1986 and on January 7, 1987, EPA held an informational
meeting in the Municipal Anex Building in North Smithfield, RI to
describe the plans for the RI/FS.
*
On July 19, 19£8, EPA held an informational meeting to discuss
the results of the RI, the alternatives presented in the FS and
EPA's preferred alternative. This information was summarized and
published in EPA's Proposed Plan, July 1988. The Proposed Plan
was distributed to people on EPA's mailing list and other
interested people at the meeting. Also during this meeting, the
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ROD DECISION SUMMARY page 7
Landfill & Resource Recoverv Site
Agency responded to questions from the public. From July 20 to
September 2, 1988, the Agency held a six week public comment
period to accept public comment on the alternatives presented in
the FS and the Proposed Plan and on any other documents
previously released to the public. On August 10, 1988, the
Agency held a formal public hearing to accept any oral comments.
A summary of the comments submitted and the Agency's response to
comments are included in' the Responsiveness Summary of this
document.
IV. SCOPE OF RESPONSE ACTION
The selected remedy has four major components which together
comprise a comprehensive approach for Site remediation. In
summary, the remedy consists of the following components:
upgrading the existing landfill closure; constructing a gas
collection and thermal destruction system to treat the landfill
gas; remediating the impacted wetlands; and monitoring the Site.
The selected remedy will reduce the principal threats posed by
the Site. Gaseous emissions from the landfill pose the principal
threat to human health at the Site. The gas collection and
thermal destruction system will reduce this threat. The sand
eroding from the landfill poses a principal threat to the
environment. Specifically, the sand is filling in wetlands that
surround the Site. Upgrading the landfill closure will reduce
this threat as well as the potential threat to groundwater from
infiltration of rain and -melted snow. The impacted wetlands will
be remediated. Site monitoring will insure that the selected
remedy remains protective of human health and the environment.
V. SITE CHARACTERISTICS
The RI consisted of evaluating existing data and gathering
additional data needed to characterize the Site. Additional data
was gathered for the following media: air, groundwater,
subsurface soils, surface water, and surface water sediments.
The significant findings of the Remedial Investigation are
summarized below. A complete discussion of the Site
characteristics can be found in Sections 7 and 8 of the RI/FS
Report.
A. Air
During the RI, the 18 landfill vents were opened and the
emissions were evaluated to determine the landfill's impact on
air quality. The vents were sampled and found to be releasing
methane and hydrogen sulfide gas contaminated with a variety of
volatile organic compounds (VOCs). Five of the 18 vents
contained significantly higher concentrations of VOCs. The
locations of these vents (12, 13, 15, 17 and 18) were coincident
with the proximate area where hazardous waste was disposed (see
Figure V-l: Location of Landfill Vents).
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LftRR
LANDFILL
PROPERTY LINE
(Figure V-l
Location of Landfill Vents
SITE TRAILER
SCALE:
1 MUCH » 200 FEET
oo
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ROD DECISION SUMMARY page 9
Landfill & Resource Recovery Site
Samples of the air were also taken at locations above the portion
of the landfill that is not covered by the synthetic cap. These
results indicated that methane and hydrogen sulfide gas
contaminated with VOCs are also released from the uncovered
area.
B. Groundwater and Subsurface Soils
EPA collected and analyzed groundwater samples from 14 on-site
groundwater monitoring veils (see Figure V-2: Monitoring Well
Locations) and evaluated historical information available from.
earlier groundwater studies. Low levels of VOCs and metals
(lead, cadmium, and arsenic) were present down gradient from the
Site. The detection of these compounds was sporadic and unevenly
distributed and the concentrations were all below EPA's drinking
water maximum contaminant levels (MCLs). The presence of a
plume of hazardous contaminants moving away from the Site is not
evident from present and historical data. Since historical
information indicates that hazardous wastes have been disposed in
the landfill, there are three possible explanations for the
analytical results seen to date. The first possible explanation
is that there are migrating hazardous constituents which have not
yet entered the groundwater. The second possible explanation is
that there is contaminated groundwater which has not .yet been
transported beyond the boundary of the landfill, where the
monitoring wells are located. The third possible explanation is
that the existing landfill conditions, such as the natural
hydrologic and geologic conditions within the landfill, the
quantity of hazardous-wastes disposed and the existing cover,
could be preventing the migration or detection of a groundwater
contaminant plume.
Iron, manganese, chloride and specific conductance were detected
in the groundwater at slightly elevated levels, above ambient
conditions, down gradient from the Site. These compounds are
typically found in the groundwater migrating from municipal
landfills and do not have a high toxicity.
The investigation indicated that groundwater in the vicinity of
L&RR flows to the east and southeast and discharges into
tributaries of Trout Brook and wetlands adjacent to the Site.
The average rate of groundwater flow was estimated to range from
5 to 10 ft/year in the upper kame delta deposits and from 230 to
460 ft/yr in the lower ice contact deposits.
EPA also reviewed residential well data generated by the Rhode
Island Department of Health. Low levels of VOCs were present in
some of the residential wells with no consistent '.trends. In some
instances, the types of VOCs detected were different than those
detected in the on-site monitoring wells.
Subsurface soil samples were obtained during the drilling of the
groundwater monitoring wells. The results of the analyses did
not indicate the presence of significant levels of contaminants.
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ROD DECISION SUMMARY page 11
Landfill & Resource Recovery Site '
In summary, based on all the data generated, EPA concluded that
a plume of hazardous contaminants is not yet migrating from.the
Site. All contaminants are below MCLs. The elevated levels of
iron, manganese, chloride and specific conductance are typical of
an inorganic plume migrating from a municipal landfill. Finally,
the L&RR Site is not presently impacting the local private wells.
Contaminants found at those wells are presently attributed to
sources other than the L&RR landfill.
C. Surface Water and Sediments
To characterize impacts to local area streams, samples of the
surface water and sediments were taken (see Figure V-3: Surface
Water and Sediment Locations). As in the case of the
groundwater, the surface water and sediments also contain very
low levels of VOCs. Slightly elevated levels of inorganic
compounds were also detected.
VI. SUMMARY OF SITE RISKS
Using the data collected during the RI, a risk assessment was
conducted to evaluate the present and future risks posed to
public health and the environment from lifetime exposure to
contaminants at the L&RR Site. The risk assessment is performed
assuming that further remedial actions will not be conducted and
is intended to indicate which routes of exposure present a risk
that warrants remedial actions. The risk assessment was
conducted in two parts: a public health assessment and an
environmental assessment.
A. Public Health Assessment
A Public Health Assessment (PHA) was performed to estimate the
probability and magnitude of potential adverse human health
effects from exposure to contaminants associated with the Site.
Seventeen contaminants of concern, listed in Table VI-1, were
selected for evaluation in the PHA. These contaminants
constitute a representative subset of the more than 30
contaminants identified at the Site during the RI. The 17
contaminants were selected to represent potential on-site hazards
based on toxicity, concentration, mobility and persistence in
the environment, and frequency of detection.
Potential human health effects associated with the contaminants
of concern in groundwater, surface water, sediments and air were
estimated through the development of several hypothetical
exposure scenarios. Table VT-2 summarizes the potential
receptors and the significant routes of exposure for all media at
the Site.
Ingestion of groundwater is considered to be.a.potential future
route of exposure rather than a present route for three reasons.
First, on-site groundwater is not presently used as a drinking
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<*:**•/
\4 > - •/
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page 13
Table VI-1
Contaminants of Concern
MEDIA-
COMPOUND Groupdwater Surface Water Sediment Air
o .VOCs
2-butanone X X X
toluene X X
trans-1,2-dichloroethene X
1,1-dichloroethane X
chloroform X
1,2-dichloroethane X
carbon tetrachloride X
benzene X
1,1,-dichloroethene X
methylene chloride X
tetrachloroethene X
1,1,2,2-tetrachloroethane X
trichloroethene X
ethyl benzene X
o SVOCs
none selected
o Pesticides
none selected
o Inorganics
arsenic X X
lead X X
zinc X
12.87.73T
0007.0.0
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page 14
Table VI-2
Summary of Exposure Routes
Point of Route of Exposed
Medium Exposure Exposure Population Status
Ground- Dovngradient Ingestion Adults & Future
water veils children
Surface Eastern Dermal Children Current
water Edge absorption
Southern
Edge
Western
Edge
Sediments Eastern Dermal Children Current
Edge absorption
Southern
Edge
Air Vents on Inhalation Adults & Current
Emissions landfill children
and disper-
sion downwind
12.87.73T
0008.0.0
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ROD DECISION SUMMARY page 15
Landfill & Resource Recovery Site
water source. Second, based on the information gathered to
date, a contaminant plume is presently not migrating from the
Site and impacting off-site private wells. Finally, the
landfill is located over the Slatersville Aquifer which is
classified as a potential future drinking water source, so that
there is a threat of future releases from the Site into drinking
water.
The streams near the Site are rather shallow and swimming is not
considered probable. However, children who might play near the
Site could be exposed by wading in such streams. Adults are not
expected to use the Site for this purpose and are therefore not
considered to be exposed to contaminants in the surface water and
sediments.
Gaseous emissions from the landfill vents as well as fugitive
emissions from the surface of the landfill are considered to be
potential routes of exposure. Presently, the landfill vents are
closed and the majority of the gaseous emissions are retained at
the Site. However, these vents will eventually have to be opened
to protect the integrity of the landfill's synthetic cover from
pressure building up within the landfill.. Therefore, inhalation
of the vent emissions is a potential future route of exposure.
EPA's exposure scenarios are designed to identify the level of
clean-up that would be acceptable without the need for long term
management, such as a fence, to prevent on-site exposure. In
assessing the risks associated with the landfill emissions,
separate exposure scenarios were utilized for children and
adults because children could be expected to play at the Site and
be exposed to the undiluted emissions from the vents.
The conclusions of the public health assessment are as follows:
o Of all the potential risks evaluated at the Site,
exposure to gaseous emissions from the landfill pose the
highest health risk. If the vents were opened and
neighboring residents were exposed throughout their
lifetime to the gaseous emissions from the vents, a
potential risk to public health could result from
exposure to these gases. Furthermore, children who
might play on the landfill are at the greatest risk.
o Exposure to groundwater at the boundary of the Site does
not presently pose a significant risk to public health.
It is important to note that it was determined from the
data collected that the L&RR Site is not presently the
source of contamination in the residential wells near the
Site. EPA has requested that the State of Rhode Island
investigate other potential sources of contamination for
these wells.
o Exposure to surface water and sediments adjacent to the
Site does not presently pose a significant risk to public
health.
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ROD DECISION SUMMARY page 16
A complete discussion of the Public Health Assessment can be
found in Section 11 of the RI/FS Report.
B. Environmental Assessment
•
This part of the risk assessment evaluated risks posed to the '
wetlands and various wildlife including aquatic organisms at the
Site from exposure to pollutants and contaminants. The
assessment concluded that the only significant environmental
threat is to the wetlands surrounding the Site (see Figure VI-
1: Wetland Community Section). The wetlands are being impacted
by soil eroding from the landfill cover. The eroded soil is not
contaminated; however, it is filling in the wetlands, destroying
vegetation and decreasing the ability of the wetland area to
support indigenous plant and animal life.
A complete discussion of the Environmental Assessment can be
found in Section 10 of the RI/FS Report.
VII. LANDFILL CLOSURE ASSESSMENT
In 1983, LfcRR, Inc., entered into a Court Order and Consent Order
and Agreement ("the 1983 Court Order") with RIDEM, to close the
landfill according to plans incorporated into the Order. EPA
commented on these plans but was not a party to this Court Order.
The 1983 Court Order, the plans and the data supporting them
failed to meet the requirements of the National Contingency Plan
(NCP). Negotiations for the conduct of an RI/FS in conformance
with the NCP were conducted between EPA and L&RR, Inc., but an
agreement was not reached. The owner closed the landfill
according to the plans in the 1983 Court Order when landfilling
stopped in January of 1985.
During 1985 and 1986, GCA Corporation, under contract to EPA,
observed the Site closure operations and evaluated its compliance
with the Resource Conservation and Recovery Act (RCRA), Subtitle
C, regulations. Section 40 CFR Part 264 of the RCRA regulations
contains requirements governing design, construction, operation,
maintenance, disposal, closure and post-closure of a hazardous
waste facility. Some of these regulations are considered
relevant and appropriate requirements for the Site since the L&RR
Site contains wastes that are listed in RCRA as hazardous wastes
and these wastes were accepted for disposal prior to 1980 (See
Tables XII-1,2 and 3). The information obtained by GCA was
intended to supplement information obtained during EPA's RI/FS.
CCA's observations and findings were documented in the Compliance
Oversight Report by GCA, dated June 1986. EPA began the RI/FS in
May of 1986. During the RI, EPA evaluated the performance of the
landfill closure as it had been conducted to date. The
significant finding are summarized below.
-------
Figure VI-1
WETLAND COMMUNITY SECTION
L ft RH SITE
NORTH SMITHFELD. RHODE ISLAND
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ROD DECISION SUMMARY page 18
A. Evaluation of the Cover's Performance
During the RI, data was gathered from the existing landfill to
assess the performance of the existing cover. The'landfill was
assessed according to the following factors: cover drainage,
vegetation, erosion of cover soil, and the stability of the side
slopes.
Using the Hydrogeologic Evaluation of Landfill Performance (HELP)
model, Version I, the assessment concluded that approximately
749,000 gal/acre/yr of infiltration enters the waste in the 4.9
acre area without the synthetic cover and subsequently leaches
from the base of the landfill. This infiltration comprises 59%
of the average annual rainfall. The maximum infiltration in the
rest of the landfill, which has a synthetic cover as part of the
cover system, was estimated to be 7,690 gal/acre/yr or 0.6% of
the average annual rainfall. In response to the comments
received during EPA's public comment period, the infiltration in
the uncovered area was recalculated using the Thornthwaite and
Mather method as republished by Fenn, Hanley and DeGeare, in
1977. Using this method, the infiltration in the uncovered area
was calculated to be approximately 435,00*0 gal/acre/yr which is
34% of the average annual rainfall.
The existing landfill surface water drainage system is not
designed or constructed to handle peak velocity flows from heavy
precipitation and the landfill lacks vegetation, particularly in
the area without a synthetic cover. Both of these factors result
in the potential for excessive erosion. Current erosion from'the
landfill ranges from 0.5 to 38.3 tons/acre of cover soil per
year. Ultimately, the eroded soil is deposited in wetland areas
surrounding the Site. The steep side slopes are marginally
stable. Accepted engineering practice is to design the slopes so
that a factor of safety against cover sliding is at least 1.25.
For the steep slopes at the Site, the factor of safety ranged
from 1.02 - 1.15.
During the RI, EPA also assessed the performance of a
hypothetical cover. The specifications for this hypothetical
cover were generated using the EPA guidance document entitled
Covers for Uncontrolled Hazardous Waste Sites (EPA/540/2-85/002;
September 1985). A cover constructed according to this guidance
results in 2% of the average annual rainfall leaching from the
base of the landfill. Also, an estimated 2 tons/acre of soil per
year would erode from the cover. The guidance document also
provides information on constructing the surface water drainage
system to handle peak flows and to minimize erosion. To assess
whether the existing cover met the requirements 6f the RCRA,
Subtitle C, regulations, the performance of the two covers was
compared. The conclusions of this assessment are presented
below.
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ROD DECISION SUMMARY page 19
Landfill t Resource Recovery Site
B. Compliance with Federal and State RCRA Requirements.
Some of the RCRA, Subtitle C, regulations are considered relevant
and appropriate requirements for the L&RR Site. During the
assessment, it was determined that the existing landfill closure
does not meet the RCRA regulations as outlined in 40 CFR Subpart
N, § 264.310. Specifically, it does not minimize erosion; it
does not minimize infiltration of liquids such as rain and melted
snow and it does not function with minimum maintenance.
Furthermore, the present Site security system does not meet the
objectives of 40 CFR Subpart B, § 264.14; the present groundwater
monitoring plan does not meet the objectives of 40 CFR Supart F,
§ 264.90 - § 264.101; and, the post closure plan does not meet
the objectives of 40 CFR Subpart G, § 264.110 - § 264.120. The
specific deficiencies pertaining to security, the groundwater
monitoring plan, and the post closure plan are discussed in
detail in the GCA Report and the RI/FS Report, which are included
in the Administrative Record.
In addition to the above, the landfill cover does not meet Rhode
Island's Rules for Solid Waste Management Facilities (R.I.G.L.
23-18.9). These rules require a total of. 24 inches of cover soil
to be maintained on the surface of the landfill. Presently, the
2:1 side slopes are only covered with approximately 1 foot of
soil. Furthermore, the erosion of the cap into the wetlands
violates the State's Wetlands law, (R.I.G.L. 2-1).
A complete discussion of the landfill closure assessment can be
found in the GCA Report and Section 9.0 of the RI/FS Report.
VIII. DEVELOPMENT AND SCREENING OF ALTERNATIVES
A. Statutory Requirements/Response Objectives
Prior to the passage of the Superfund Amendments and
Reauthorization Act of 1986 (SARA), actions taken in response to
releases of hazardous substances were conducted in accordance
with CERCLA as enacted in 1980 and the revised National Oil and
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR
Part 300, dated November 20, 1985. Until the NCP is revised to
reflect SARA, the procedures and standards for responding to
releases of hazardous substances, pollutants and contaminants
shall be in accordance with Section 121 of CERCLA and to the
maximum extent practicable, the current NCP.
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 applicable or
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ROD DECISION SUMMARY page 20
relevant and appropriate environmental standards established
under federal and state environmental lavs unless a statutory
waiver is granted; 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
statutory preference for remedies that permanently and sig-
nificantly reduce the volume, toxicity or mobility of hazardous
substances, pollutants and contaminants over remedies that do not
achieve such results through treatment. Response alternatives
were developed to be consistent with these Congressional
mandates.
Remedial response objectives define the specific aspects of a
site that must be considered during remediation. For the L&RR
Site, response objectives were formulated for the landfill
closure, wetlands and landfill gas based on environmental
problems defined in the public health, environmental and landfill
closure assessment. These response objectives are used to
develop appropriate remedial alternatives and are as follows:
o remediate the landfill so that federal and state
applicable, relevant and appropriate requirements
are met and to insure that the landfill is
protective of human health and the environment;
o- reduce present and future impacts to wetlands due to
sedimentation of eroded landfill cover material;
o remediate the wetlands already impacted by
sedimentation; and
o remediate the landfill gas so that VOC concentrations in
ambient air are reduced and risks to public health and
the environment are minimized.
B. Technology and Alternative Development and Initial
Screening
CERCIA, the NCP, and EPA guidance documents including, "Guidance
on Feasibility Studies Under CERCLA" dated June 1985, and the
"Interim Guidance on Superfund Selection of Remedy1* [EPA Office
of Solid Waste and Emergency Response (OSWER)], Directive No.
9355.0-19 (December 24, 1986) set forth the process by which
remedial actions are evaluated and selected. In accordance with
these requirements and guidance documents, a range of
alternatives were developed for the Site. In accordance with
Section 121 of CERCLA, this range must include the following
categories: a no action alternative, alternatives that utilize
containment technologies and treatment alternatives ranging from
an alternative that would eliminate the need for long-term
management (including monitoring) at the Site to alternatives
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ROD DECISION SUMMARY page 21
Landfill & Resource Recovery Site
that utilize treatment to reduce the nobility, toxicity, or
volume of the hazardous substances as their principal element.
Section 121(b)(l) of CERCLA presents several factors that at a
minimum EPA is required to consider in its assessment of
alternatives. In addition to these factors and the other
statutory directives of Section 121, the evaluation and selection
process was guided by the EPA document "Additional Interim
Guidance for FY '87 Records of Decision1* dated July 24, 1987.
This document provides direction on the consideration of SARA
cleanup standards and sets forth nine factors that EPA should
consider in its evaluation and selection of remedial actions.
The nine factors are:
1. Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs).
2. Long-term Effectiveness and Permanence.
3. Reduction of Toxicity, Mobility or Volume.
4. Slant-term -Effectiveness.
5. Implementability.
6. Community Acceptance.
7. State Acceptance.
8. Cost.
9. Overall Protection of Human Health and the Environment.
Section 15 of the RI/FS Report identified, assessed and screened
technologies based on Site and waste characteristics such as
geology and hydrology; availability of space and resources; the
presence of special Site features; the contaminated media; and,
the type and concentrations of wastes. These technologies were
combined into remedial alternatives that would provide a
comprehensive remedial approach to the Site. At the conclusion
of this process, 6 remedial alternatives were developed for the
Site: a no action alternative (Alternative 1), four containment
alternatives (Alternatives 2-5) and a treatment alternative
(Alternative 6). These alternatives are presented in
Table VIII-1.
Alternatives 3, 4 and 5 contain a landfill gas treatment
component. Three thermal destruction technologies were
identified for treating the landfill gas: combustion, flaring and
incineration. During the FS, it was determined that any one of
these technologies could be included with any one of the
alternatives.
-------
Table VIII-1
Alternatives Developed for
LANDFILL AND RESOURCE RECOVERY
Alternative
Description of
Key Components
Alternative 1: No-action
i
Alternative 2: Vegetation
Establishment
Alternative 3: Synthetic Cover
Installation/Slope Stabilization
• Groundwater monitoring for indicators of contaminant Migration.
• Groundwater monitoring for indicators of contaminant migration.
- Post-closure plan development to monitor, maintain, and inspect site.
- Surface water management to minimize erosion of final cover and minimize
maintenance requirements.
- Vegetation establishment to minimize erosion of final cover.
- Vegetation establishment on 2:1 side slope to minimize erosion and enhance
evapotranspiration.
- Cover thickness establishment (a minimum of 24 inches to meet ARARs).
- Hinimal gas control to enhance vegetation and, therefore, minimize erosion and
maintenance.
- Sediment removal in wetland and on-site disposal.
- Fence installation to limit site access.
- Groundwater monitoring for indicators of contaminant migration.
- Post-closure plan development to monitor, maintain, and inspect site.
- Surface water management to minimize erosion of final cover and minimize
maintenance requirements.
- Vegetation establishment to minimize erosion of final cover.
- Cover thickness establishment (a minimum of 24 inches to meet ARARs).
- Slope stabilization by flattening 2:1 side slope to 2.5:1 and constructing
terrace along new slope.
- Synthetic cover installation on terraced 2.5:1 side slope to minimize) maintenance
and the migration of fluids through the landfill.
• Landfill gas treatment.
- Sediment removal in wetlands and on-site disposal.
- Fence installation to limit site access.
12.87.85
0006.0.0
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Table VIII-1
Alternatives Developed for
LANDFILL AND RESOURCE RECOVERY
Continued
Alternative
Description of
Key Components
Alternative 4: Slope Flattening/
Synthetic Cover Installation
Alternative 5: RCRA Guidance Cover
Installation
Alternative 6: Excavation and
Treatment
Groundwater nonitoring for indicators of contaminant Migration.
Post-closure plan development to monitor, maintain, and inspect site.
Surface water management to minimize erosion of final cover and minimize
maintenance requirements.
Vegetation establishment to minimize erosion of the final cover.
Cover thickness establishment (a minimum of 24-inches to meet ARARs).
Flatten 2:1 side slope to 3:1 in unlined area to minimize erosion and maintenance.
Synthetic cover installation on 2:1 side slope.
Landfill gas treatment.
Sediment removal in wetlanda and on-site disposal.
Fence installation to limit site access.
Groundwater monitoring for indicators of contaminant migration.
Post-closure plan development to monitor, maintain, and inspect site.
Surface water management to minimize erosion of final cover and minimize
maintenance requirements.
Construction of a RCRA guidance cover over the existing cover:
o flatten 2:1 side slope to 3:1
o synthetic cover installation for 2:1 side slope area
o clay cover installation over entire site
o vegetation establishment including a drainage layer
Landfill gas treatment.
Sediment removal in wetlands and on-site disposal.
Fence installation to limit site access.
Excavation of landfill wastes to prevent contaminant migration.
Incineration of removed wastes prior to placement in RCRA-compliant
facility.
Sediment removal and on-site disposal.
12.87.85
0007.0.0
Jl
(D
K)
U>
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ROD DECISION SUMMARY page 24
& Resource Recoverv Site
In Section 16 of the RI/FS Report, the alternatives were
screened according to effectiveness, implementation and cost.
The purpose of this screening was to narrow the number of
potential remedial alternatives for further detailed analysis
while preserving a range of alternatives for the Site. As a
result of this screening process, Alternative 6, vhich utilized
treatment (excavation and incineration) as a primary component
and eliminated the need for long-term Site monitoring, was
eliminated as a potential remedy because public health and
environmental risks would be posed by its implementation. A
detailed discussion of the reasons for elimination are presented
in Appendix AA of the RI/FS Report, and in Section XII.D. of this
document.
IX. DESCRIPTION/SUMMARY OF THE DETAILED AND COMPARATIVE
ANALYSIS OF ALTERNATIVES
After the screening process, a detailed analysis was conducted on
the five remaining alternatives. A detailed analysis was also
conducted on each of the gas treatment technologies. Based on
the conclusions of the analysis, the selected remedy would
include one of the alternatives and one of the gas treatment
technologies. This section presents a narrative summary and
brief evaluation of each alternative and each technology
according to the evaluation criteria described above.
A. Alternatives Analyzed
The five alternatives that were analyzed in detail for the Site
include a no action alternative (Alternative 1) and four
containment alternatives (Alternatives 2-5).
Alternative 1 Approximate Present Worth Cost:
No Action $ 850,000.
The no action alternative would not require further remediation
to the landfill closure conducted to date according to the 1983
Court Order between L&RR, Inc., and RIDEM but would consist
solely of long-term groundwater monitoring. Each existing well
would be sampled on a quarterly basis and analyzed for specific
parameters identified in Table 18-1 of the RI/FS Report. Because
this alternative results in wastes remaining on-site, the Site
would be reviewed on a periodic basis.
This alternative would not be protective to public health and the
environment because it does not reduce the existing risks
associated with exposure to landfill gas emissions; it does not
reduce impacts to the surrounding wetlands; it would not reduce
the potential for off-site releases into groundwater resulting
from infiltration; and, it would not comply with ARARs,
specifically the RCRA regulations outlined in Section VII of this
document.
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ROD DECISION SUMMARY page 25
landfill t Resource Recoverv Si tie
A detailed assessment of this alternative can be found in Section
18 of the RI/FS Report.
Alternative 2 Approximate Present Worth Cost:
Vegetation Establishment $3,970,000.
This alternative consists of the following components:
o removing sediments and reseeding the wetlands;
o installing a chain linked fence;
o developing a post closure plan;
o upgrading the present surface water runoff management
system;
o establishing a cover thickness of 24 inches;
o establishing vegetation; and,
o installing a passive gas collection system.
This alternative includes components that would upgrade the
landfill closure conducted to date according to the 1983 Court
Order. Establishing vegetation and upgrading the surface water
runoff management system would minimize erosion and maintenance.
The wetlands surrounding the Site would be restored and future
impacts would be mitigated.
As discussed in Section VII of this document, EPA's RCRA
regulations, 40 CFR 264 are relevant and appropriate for this
Site. The RCRA landfill closure requirements in 40 CFR § 264.310
would not be satisfied by this remedy, because it would not
provide long-term minimization of migration of liquids through
the landfill (§ 264.310(a)(1)), in the area that is not capped by
a synthetic cover. The excess infiltration increases the
potential for groundwater contamination. Although an organic
plume has not yet been detected, it is expected that one may .
emerge in the future. Therefore, the long-term protectiveness of
this alternative is questionable. This alternative is readily
implementable, taking approximately 2-3 months to design and
construct, and would require long-term monitoring and
maintenance.
This alternative does not contain gas treatment because it is
difficult to implement a treatment system with this alternative.
The landfill gas would be diluted with uncontrolled amounts of
air that would be drawn in from the area which does not have a
synthetic cover. The air would lessen the combustibility of the
landfill gas. Therefore, this alternative includes a passive gas
collection system. This system would direct the landfill gas
away from the uncovered area of the landfill to minimize the
destruction of vegetation in this area. The existing landfill
vents would be opened to prevent the build up of gases under the
liner. Since this system does not involve treatment, the
toxicity of the gas would not be reduced and the potential risks
to public health would remain. Therefore, EPA does not consider
this alternative protective of public health. In addition, this
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ROD DECISION SUMMARY page 26
ft Resource RACOVATV
alternative dots not satisfy the statutory preference for
treatment, which is satisfied by other alternatives providing gas
treatment.
•
A detailed assessment of this alternative can be found in
Sections 19 and 20 of the RI/FS Report.
Alternative 3 Approximate Present Worth Cost:
Synthetic Cover Installation/ ** $ 5,062,000.
Slope Stabilization
This alternative consists of the following components:
o removing sediments and reseeding the wetlands;
o installing a chain linked fence;
o developing a post closure plan;
o upgrading the present surface water runoff management
system;.
o establishing a cover thickness of 24 inches;
o establishing vegetation;
o installing a synthetic cover on the uncovered area;
o stabilizing the 2:1 side slopes by slightly extending the
slope and installing a terrace; and
o gas collection and treatment;
This alternative contains most of the components in Alternative 2
except this alternative includes installing a synthetic cover on
the uncovered area of the landfill and stabilizing the 2:1 side
slope. Installing the synthetic cover will minimize
infiltration. Stabilizing the side slopes will minimize erosion
and maintenance as well as protect the integrity of the
synthetic cover. Therefore, this alternative complies with RCRA
regulations. Also, since infiltration is minimized and the 2:1
slopes are stabilized, this alternative provides improved long
term protectiveness by minimizing the potential for groundwater
contamination. In this alternative, the slopes would be
stabilized by extending the slope slightly and constructing a
terrace. Approximately 1 acre of land adjacent to the landfill
would have to be acquired to implement this alternative.
Due to the steepness of the side slopes, this alternative will be
relatively difficult to implement, taking approximately 9 to 11
months to design and construct. The stability of the slopes
will have to be tested during the design phase.
This alternative contains a gas collection and treatment process
that would reduce the toxicity of the gas and reduce the risks to
public-health from exposure to the landfill gas, A discussion of
this system is presented in the next section of this document,
Section X.B.
Because this alternative would be protective of public health and
the environment, and would comply with ARARs, it has been
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ROD DECISION SUMMARY page 27
Landfill & Resource Recoverv Site
tentatively selected as the selected remedy, pending a
determination of its implementability (see Sections XI of this
document).
A detailed assessment of this alternative can be found in
Sections 19 and 21 of the RI/FS Report.
** Cost does not include the cost of gas collection and
treatment.
Alternative 4 Approximate Present Worth Cost:
Synthetic Cover Installation/ ** $ 5,490,000.
Slope Flattening
This alternative contains all of the components in Alternative 3
except this alternative utilizes a different technique to
stabilize the steep side slopes. In this alternative, the slopes
would be extended and flattened.until a slope of 3:1 is achieved.
This slope is less steep and is recommended in EPA's guidance for
constructing covers that comply with RCRA regulations. This
alternative would provide the same level of protection as
Alternative 3 but would be easier to implement.because of the
reduction in the steepness of the slopesI Present estimates show
this alternative to be slightly more expensive than Alternative
3. Approximately 3 acres of land would have to be acquired to
implement this alternative and it would also take about 11 months
to design and construct.
Because this alternative would also be protective of public
health and comply with ARARs, this alternative has been retained
as an alternate selected remedy (see Section XI of this
document).
A detailed assessment of this alternative can be found in
Sections 19 and 22 of the RI/FS Report.
** cost does not include the cost of gas collection and
treatment.
Alternative 5 Approximate Present Worth Cost:
RCRA Guidance Cover ** $ 11,670,000.
This alternative consists of the following components:
o removing sediments and reseeding the wetlands;
o installing a chain linked fence;
o developing a post closure plan; —
o upgrading the present surface water runoff management
system;
o constructing a cover according to EPA's RCRA guidance
which would include flattening the 2:1 side slope,
installing a synthetic cover on the flattened slope,
placing a clay barrier over entire Site, and establishing
vegetation (including placement of a drainage layer); and
o gas collection and treatment.
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BOD DECISION SUMMARY page 28
l ft Resource Recoverv
This alternative is similar to Alternatives 3 and 4 except that
it complies with both the RCRA regulations and the specifications
in EPA's guidance document discussed in Section VII. The RCRA
closure guidance is not an ARAR but is to be considered.
Alternatives 3 and 4 would not include all the elements called
for in the guidance, but they would meet the RCRA closure
performance standards. This alternative provides the same level
of protection as the previous two alternatives but is twice the
cost. EPA has determined that this alternative is not the most
cost effective alternative. Due to the additional requirements,
it would take approximately 3 years to design and construct this
alternative.
A detailed assessment of this alternative can be found in
Sections 19 and 23 of the RI/FS Report.
** Cost does not include the cost of gas collection and
treatment.
B. Gas Treatment Technologies Analyzed
Three thermal destruction technologies underwent detailed
analysis for the L&RR Site: combustion, flaring and incineration.
Thermal destruction consists of burning the landfill gas to
destroy the hazardous constituents. Typically, these
technologies can destroy between 90% and 99.99% of the gas that
enters the system. With the concentration of hazardous
constituents from the RI and this removal efficiency, these
technologies will be protective of human health and the
environment and achieve ARARs. However, each of the technologies
has advantages and disadvantages with regards to factors such as
implementability and cost which can not be adequately assessed
without Site specific pilot tests. A brief discussion of each
technology is given below.
A detailed assessment of each technology can be found in Section
24 of the RI/FS Report.
Technology 1 Approximate Present Worth Cost:
Combustion $1,300,000.
The combustion process is a process that burns the landfill gas
and also generates electricity as a useful by-product.
Therefore, this technology is a resource recovery technology.
Several combustion systems have been installed at municipal
landfills and have been demonstrated for burning conventional
municipal landfill gas, typically achieving 90% destruction.
However, little information is available on the:, effectiveness of
burning hazardous constituents. Also, due to the acidic
compounds present in the gas, corrosion of the equipment may
occur and increase maintenance costs.
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ROD DECISION SUMMARY page 29
Landfill t Resource Recoverv Site
Technology 2 Approximate Present Worth Cost:
Flaring $612,000.
The flaring process is similar to combustion except that it does
not contain a generator and therefore will not produce
electricity. Flaring has been demonstrated to be effective in
removing hazardous constituents in miscellaneous gas streams.
Ninety percent (90%) removal efficiencies have been demonstrated.
However, corrosion could increase maintenance costs.
Technology 3 Approximate Present Worth Cost:
Incineration $1,277,000.
Incineration is a two step process which routinely achieves 99 to
99.99% destruction. Incinerators have been demonstrated for
burning both municipal landfill gas and gas streams containing
hazardous wastes. The technology is readily implementable.
X. DOCUMENTATION OF SIGNIFICANT CHANGES
There are no significant changes from EPA's Proposed Plan in
EPA's selected remedy.
XI. THE SELECTED REMEDY
A. Description of the Selected Remedy
The selected remedy has four major components which together form
a comprehensive approach to Site remediation. The first two
components, upgrading the landfill closure completed to date and
treating the landfill gas, are intended to control the source •
and minimize the potential of hazardous substances migrating from
the Site. Remediation of the impacted wetlands is the third
major component which will occur after the landfill has been
upgraded. The fourth component, Site monitoring, will insure
that the landfill and the gas treatment components remain
effective.
1. Upgrading the Landfill Closure
The existing landfill closure will be upgraded to meet ARARs and
to insure that it effectively contains the hazardous wastes. Two
alternatives were selected from the alternatives developed in
the FS: Alternative 3: Synthetic Cover Installation/Slope
Stabilization and Alternative 4: Synthetic Cover " ~~
Installation/Slope Flattening. These two alternatives are
equally protective. Alternative 3 is estimated 'to be slightly
less expensive. However, due to the steepness of the side slopes,
this alternative may be relatively difficult to implement,
causing the costs to increase. Also, the stability of the side
slopes must be evaluated during the design phase. Due to the
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ROD DECISION SUMMARY page 30
& Resource Reeoverv Site
question concerning implementability, Alternative 4 has also been
chosen as a possible alternative. The choice between the two
alternatives will be specified during the design phase. The
components of these alternatives are described below.
Fence installation; Site security will meet the requirements of
40 CFR f 264.14. To limit Site access and maintain Site
security, a chain-linked fence with barbed wire will be
constructed around the facility. Along this fence, two access-
road gates (at the facility's north and south entrances from the
Oxford Turnpike) and two walkway gates (on the northern and
southeastern sides of the Site) will be installed. The walkway
gates provide convenient access to off-site monitoring wells.
The gates will be kept locked and the fence will be posted with
warning signs.
Post-closure Plan Development: Closed hazardous waste disposal
facilities must be inspected, monitored, and maintained to
prevent adverse effects to human health and the environment in
accordance with 40 CFR Part 264.110-264.120; 264.300-264.339 and
264.340-264.599. The post-closure plan will specify how these
goals will be achieved at L&RR and must be approved by both EPA
and the State. The L&RR post-closure plan will contain plans for
monitoring groundwater and landfill gas. In addition, the post-
closure plan will describe planned operations, or maintenance and
inspection activities, and the frequencies of those activities.
At L&RR, these activities will include the following:
o inspection and maintenance of gas and groundwater
monitoring equipment;
o periodic mowing;
o inspection and maintenance of the cap's integrity;
o inspection and maintenance of the gas collection and .
treatment system
o inspection and maintenance of surface water management
system
o inspection and maintenance of the security fence; and
o protection and maintenance of surveyed benchmarks.
The L&RR post-closure plan will include a schedule of activities
planned during the post-closure period. The post-closure period
begins upon certification by an independent registered
professional engineer that closure has been completed in
accordance with the plan. Post-closure care must last for 30
years unless the post-closure plan is amended.
Surface Water Management System• To limit the potential for
further environmental impact due to erosion and to minimize cover
maintenance, the present surface water management system will be
upgraded and expanded. First, a stone-lined perimeter drainage
channel will be added to transport high-volume storm flows
(i.e., 24 hour, 25-year storm event) to the sedimentation
basins. The perimeter channel will collect most of the surface
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ROD DECISION SUMMARY page 31
l & Resource Recovery Site
water. At the southwestern side of the Site, surface water will
discharge to the existing roadside ditch along Oxford Turnpike.
Second, surface water diversions will be more closely spaced,
approximately 200 feet apart on vertical 3:1 slopes. Finally, if
the slope is extended, the existing sedimentation.pond (P-3) on
the northeastern section of the Site will be relocated.
Cover Thickness Establishment; Cover soil consisting of an 18
inch sand layer and a 6 inch topsoil layer capable of supporting
vegetation will be added to areas which presently do not have a
cover thickness of 24 inches.
Vegetation Establishment; Although vegetation is present on the
landfill, it is stressed in some areas. To enhance vegetation,
stabilized municipal 'waste water treatment plant sludge will be
incorporated into the top soil. The sludge will be mixed into
the soil using a rototiller or disc harrow and the area will be
hydroseeded using a sprayed liquid mixture of seed (i.e.,
grass/legume) and fertilizer. During establishment of the*
vegetative cover, erosion will be controlled by applying either
hay mulch following seeding or a chemical (asphalt) binder during
seeding. Prior to use, the sludge will be analyzed to determine
whether it meets applicable requirements.
Synthetic Cover Installation/Slope Stabilization; The difference
between Alternatives 3 and 4 is the method of stabilizing the 2:1
side slope and the type of synthetic cover utilized. In
Alternative 3, the 2:1 slope will be stabilized by extending the
slope slightly to a slope of 2.5:1 and constructing a terrace
midway down the slope (see Figure XI-1: Comparison of Slope
Stabilization Techniques). Approximately 1 acre of land will
have to be acquired to construct this alternative. The unlined
area encompasses approximately 5 acres. A synthetic membrane
will be installed in this uncovered area (see Figure XI-2:
Alternative 3). To minimize the potential for slipping, a 20-mil
HOPE membrane with surface texture will be installed. In
Alternative 4, the 2:1 slope will be extended to a slope of 3:1.
Approximately 3 acres of land will be acquired. Since the
potential for slipping is much less on a 3:1 slope, a 20-mil PVC
geomembrane will be used in this alternative (see Figure XI-3:
Alternative 4). Cover soil as described in the section above
would then be added on top of the synthetic membrane.
2. Gas Collection and Thermal Destruction
Eighteen gas vents have been installed across the top of the
landfill. Each vent is made of 6-inch, slotted PVC pipe, and set
60 to 80 feet into the waste. These vents will be manifolded by
a subsurface horizontal pipe system. Using this system the
collected gas will be directed to the treatment system located
near the southern portion of the Site.
-------
Figure XI-1
Conceptual Comparison of
Slope Stabilization Techniques
Limn of Existing
Liner I
Slope Flattening
Alternative 4
Slope Stabilization
nerraced Approach)
'tentative 3
•**•'
Bi
1
Propeity
Unej
I
Existing Ground
Surface
Synthetic
Covers
-------
Figure XI-2
• Landfill & Resource Recovery Site
Alternative 3: Synthetic Cover/Slope Stabilization
page 33
Approximate Area to be
Synthetically Covered
Property Line
Approximate Area Outside
Property Line Affected by Regrading
rrrmr: Access Road
=^==gg^ Wetlands
.. Tributaries
Residences —
Undfill & Resource Recovery Site 15
-------
Figure XI-3
Landfill & Resource Recovery Site
Alternatives 4: Synthetic Cover/Slope Flattening
page 34
Trout Brook Pond f
rsnr^r: Access Road
^^2gM W«tlands
Tributariw
Residences
Approximate Area to be
Synthetically Covered
— Property Line
Approximate Area Outside
Property Line Affected by Regrading
Landfill ft Resource Rccovtiy Site 17
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ROD DECISION SUMMARY page 35
Three thermal destruction technologies have been selected to
treat the gas: combustion, flaring and incineration. As • .
discussed above, these technologies will be protective of human
health and the environment and achieve ARARs. However, each of
the technologies has advantages and disadvantages in regards to
factors like implementability and cost which can not be
adequately assessed without Site specific pilot tests.
Therefore, the specific technology to be utilized for thermal
destruction will be chosen by EPA during the design phase when
specific information regarding the performance of each is
available. A brief description of each technology is given
below.
CfnniMig^ifrfl; Because the landfill gas contains approximately 50%
methane, it can be used to generate electricity. Combustion.is a
four step process that burns the landfill gas and utilizes the
energy created from burning the gas to generate electricity. The
process is as follows: (1) condensation/acid scrubbing to remove
moisture and organic acids; (2) burning the landfill gas in an
internal combustion engine; (3) electricity production using
generators for resource recovery; and, (4) discharge of
combustion products to atmosphere.
Since organic acids tend to bind to water molecules, the moisture
present in the landfill gas will be used to remove the acids
present in the gas by passing the gas through a condenser. This
acid waste stream is a RCRA hazardous waste that will be handled
in compliance with the RCRA regulations. To obtain a proper
burning mixture, some air must be added to the gas. Auxiliary
fuel will be used to bring the engine to the proper operating
temperature. After start up, the methane in the landfill gas
will be used to fuel the engine. The electricity generated could
be transmitted to area transmissions lines for use.
Flaring; The flaring system is similar to combustion except it
does not contain a generator to convert the energy created into
electricity. The steps are as follows: (1) condensation/acid
scrubbing to remove moisture and organic acids; (2) flaring to
thermally degrade VOCs, hydrogen sulfide and methane; and, (3)
discharge of combustion products to atmosphere. A single
enclosed flare unit, 6 feet in diameter and 24 feet high, could
be used for a gas generation rate of 775 cfm.
Incineration; Incineration is a two step process as follows: (1)
incineration to oxidize hydrogen sulfide, VOCs and methane; and,
(2) discharge of combustion products to the atmosphere.
Unlike combustion and flaring, the incineration process is
conducted in a closed reaction chamber which operates at a much
higher temperature. This chamber also allows greater control
over reaction time of the gas. Because of these two factors,
incineration has the potential to achieve greater removal
efficiencies than combustion and flaring. Furthermore, this
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ROD DECISION SUMMARY page 36
£ RASO
system destroys the organic acids and eliminates the RCRA waste
stream.
3. Wetlands Remediation
During the RI, two areas of the wetlands were identified as
needing remediation due to cover material erosion and subsequent
sedimentation, Sections 1 and 3 (see Figure XI-4: Wetlands
Remediation). Additional areas may be defined during the design
phase if erosion has caused further damage since the RI was
conducted. In these areas, the sand which has eroded from the
landfill will be excavated and the wetlands will be revegetated.
Approximately 2 to 3 feet of sediment from Section 3 and the
southern portion of Section 1 will be excavated. Since the
eroded sand is not contaminated, the excavated sediment can be
r•deposited on-site. To promote wetland revegetation, soils
similar to those of the natural wetland will be placed, and
sedges and others species will be planted. During revegetation,
the natural contour of the wetland will be restored to maintain
the easterly flow of the creek toward the main wetland body.
4. Site Monitoring
To insure that the remedy remains protective, both the
groundwater and the air will be monitored periodically.
Groundwater Monitoring; The following monitoring wells will
compose the groundwater monitoring program.
Walla: MH-101 CW-5 A,B,C (15 wells)
MW-102 A,B CW-6 A,B,C
MW-103 A,B CW-7 A,C
MW-104 A,B
All wells except MW-104 A6B presently exist on-site. MW-104 A&B
will be located approximately between well clusters CW-6 and CW-
7, near the stream. Well 104A will be located in the ice contact
deposits and well 104B in the kame delta deposits.
The above wells will be monitored quarterly for the following
parameters: hazardous substance list(HSL) volatile organic
compounds (VOCs), pH, temperature, specific conductance,
chloride, arsenic, cadmium, iron, manganese and lead. On an
annual basis, the following additional constituents will be
analyzed for: barium, chromium, fluoride, mercury, nitrate,
selenium and silver.
Quarterly monitoring results will be compared to drinking water
maximum contaminant levels (MCLs). If an MCL is exceeded at a
given well, that well will be resampled and analyzed. Sampling
results will be reviewed on a periodic basis to determine if a
variation indicative of a plume is present. In addition, the
monitoring program will be reviewed after a minimum of five years
of monitoring is completed and may be modified.
-------
) - i /
/A *- /
XI-4 ,
WETLAND AREAS TO BE
REMEDIATED DUE TO SEDMENTATION
L ft RR SITE
NORTH SMITHFIELD. RHODE ISLAND
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ROD DECISION SUMMARY page 38
lAndfi.ll ft Resource Recovarv Site
During the remedial design, a detailed monitoring plan will be
developed and approved by EPA and RIDEM. This plan will
incorporate the requirements of this section and at a minimum
include a description of the following: sampling techniques,
development techniques, analytical methods, QA/QC program, data
presentation formats and monitoring well proposal.
The groundwater monitoring program for the LtRR Site has been
designed to satisfy the requirements of RCRA detection monitoring
(40 CFR 264.98). To meet the requirements of this section, a
monitoring program must be based on specific hydrologic
conditions and capable of identifying a groundwater contaminant
plume.
Air Monitoring; The air monitoring program will depend on the
specific technology chosen for gas treatment. This plan will be
outlined during the design phase and will specify the monitoring
locations, the sampling technique, the indicator parameters and
.frequency of monitoring. Depending on the technology, this plan
may include ambient air monitoring and emissions testing to
insure that the system is protecting public health and the
environment.
B. Point of Compliance and Target Cleanup Levels
Target cleanup levels must be set when risks are posed to public
health and the environment from exposure to contaminants at a
site. The point of compliance is the location where the target
cleanup levels are met (i.e. the perimeter of a site). The
target cleanup levels for the gaseous emissions from the landfill
are the Rhode Island Air Toxic Regulations. These regulations
set acceptable contaminant specific ambient levels. Since these
are ambient levels, the point of compliance will be at the
boundary of the Site.
C. Rationale for Selection
:
The rationale for choosing the selected remedy is based on the
assessment of each criteria listed in the evaluation of
alternatives section of this document. In accordance with
Section 121 of CERCLA, to be considered as a candidate for
selection in the ROD, the alternative must have been found to be
protective of human health and the environment and able to attain
ARARs unless a waiver is granted. In assessing the alternatives
that met these statutory requirements, EPA focused on the other
evaluation criteria, including, short term effectiveness, long
term effectiveness, implementability, use of treatment to
permanently reduce the mobility, toxicity and volumer and cost.
EPA also considered nontechnical factors that affect the
implementability of a remedy, such as state and community
acceptance.
EPA found that Alternatives 3 and 4, as described above, while
meeting the criteria of protectiveness and compliance with ARARs,
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ROD DECISION SUMMARY page 39
Landfill & Resource Recovery Site
are more cost effective than Alternative 5. A permanent remedy
was considered but not selected for reasons described in Section
XII.D. below. Alternatives 1 and 2 were rejected as not being
protective of public health and the environment.
A number of Site specific factors also impacted EPA's decision
for the Site. First, the landfill was presently closed with a
synthetic cover over most of the landfill. Second, although a
contaminant plume was presently not evident in the groundwater,
given the disposal history it is expected that a plume may
migrate from the Site in the future. Therefore, the landfill
should be closed in a manner that provides the maximum protection
possible. The selected remedy will minimize infiltration from
the presently uncovered area in order to prevent off-site
migration. Third, there is evidence of air impacts from the*
landfill vents. The selected remedy will include treatment to
reduce these impacts. And finally, the remedy will end the
erosion into the wetlands from the landfill and remediate present
impacts. Based upon these factors and the assessment outlined
above, which takes into account the statutory preferences of
CERCLA, EPA selected the remedial approach for the Site.
XII. STATUTORY DETERMINATIONS
The remedial action selected for implementation at the L&RR Site
is consistent with CERCLA and, to the extent practicable, the
NCP.
A. The Selected Remedy is Protective of Human Health and
the Environment
The remedy at this Site will permanently reduce the risks
presently posed to human health and the environment from exposure
to gaseous emissions from the landfill; from sand eroding off the
landfill and into the wetlands; and, from infiltration of rain
and melted snow through the landfill and into the groundwater.
The potential risks to public health from exposure to the
landfill gas will be reduced by treating the landfill gas using a
thermal destruction process. The three thermal destruction
technologies, combustion, flaring and incineration, typically
achieve destruction and removal efficiencies of 90-99.99%. EPA
established target cleanup levels based on Rhode Islands Air
Toxic Regulations. The annual average ambient air
concentrations established in these regulations provide a risk
that's within EPA's acceptable target range of 10""4 - 10~7.
With the results obtained during the RI and the 'removal
efficiencies stated above, these technologies will achieve the
target cleanup levels and will protect human health and the
environment. Pilot tests will be conducted during the design
phase to insure that the selected remedy is protective and
monitoring will be conducted after construction to insure that it
remains protective.
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ROD DECISION SUMMARY page 40
The present impacts to the wetlands will be remediated by
removing the eroded sand and establishing vegetation. The risk
of future impact will be minimized by upgrading the existing
landfill closure to minimize erosion. Specifically, the remedy
includes establishing a vegetative cover, stabilizing steep side
slopes and upgrading the surface water management system to
minimize erosion and the risks of future impacts to the wetlands.
Although an organic contaminant plume is not yet evident from the
analytical data collected to date, the historical data supports
the-fact that a plume could emerge in the future. The potential
risk of contaminating the groundwater will be minimized by
minimizing infiltration to the maximum extent practical.
Specifically, the selected remedy includes installing a synthetic
cover on the uncovered area of the landfill to minimize
infiltration and the risk of contaminating the groundwater.
Also, the groundwater will be monitored on a periodic basis to
insure that the selected remedy remains protective of public '
health and the environment.
B. The Selected Remedy Attains ARARs
This remedy will meet or attain all applicable or relevant and
appropriate federal and state requirements that apply to the
Site. Environmental laws which are applicable or relevant and
appropriate to the selected remedial action at the L&RR Site are:
Resource Conservation and Recovery Act (RCRA)
Clean Hater Act (CWA)
Safe Drinking Water Act
Fish.and Wildlife Coordination Act
Executive Order 11990 (Protection of Wetlands)
Clean Air Act (CAA)
Occupational Safety and Health Administration (OSHA)
Rhode Island General Law (RIGL)
Three types of ARARs were identified during the RI/FS: location,
chemical and action-specific ARARs. A brief narrative summary of
these ARARs follows.
Location-Specific ARARsr Table XII-1 lists the location-specific
ARARs that were identified during the planning stages of the
RI/FS. This table gives a synopsis of the requirement and how it
was considered in the RI/FS. For the L&RR Site, the location-
specific ARARs apply primarily to the landfill and the wetlands.
During the RI, the existing landfill closure was evaluated
according to the requirements outlined in RCRA regulations. As
discussed in Section VII, it was determined that the-«xisting
landfill closure does not minimize infiltration, does not
minimize erosion and does not function with minimum maintenance.
The selected remedy meets these requirements by1 installing a
synthetic cover on the uncovered area of the landfill to minimize.
infiltration and by upgrading the surface water management
system, stabilizing the steep side slopes, and establishing a
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ROD DECISION SUMMARY page 41
Landfill & Resource Recovery Site •
vegetative cover to minimize erosion and maintenance.
Furthermore, the selected remedy will protect the wetlands from
future impacts as required by the ARARs for the wetlands such as
the CWA.
Chemical-Specific ARARs; Table XII-2 lists the chemical-specific
ARARs, criteria, advisories and guidance for the L&RR Site.
During the RI, the chemical-specific ARARs were used to assess
the contamination at the Site and to conduct the risk assessment.
The table gives a synopsis of the requirement and explains how
these requirements were considered in the RI/FS. The significant
findings are outlined below.
i
The concentrations of contaminants in the groundwater at the
boundary of the Site were below their drinking water maximum
contaminant levels (MCLs) and the risk posed by consuming the
groundwater was within EPA's acceptable range. The selected
remedy includes groundwater monitoring to insure that it
continues to achieve ARARs.
For the surface water, some of the samples contained contaminants
(cadmium, chromiua and cine) ±2ia± vere slightly above aquatic
water quality criteria (AWQC). However, the risk assessment
indicated that the risk posed by exposure to the surface water
was within EPA's acceptable range and the local environment did
not appear stressed by the occasional exceedance. It is not
known whether these slight exceedances of the AWQC are caused by
releases from the landfill or by other causes including natural
causes. Releases from the landfill that would contribute to
surface water would come through groundwater, and can therefore
be detected in the planned groundwater monitoring which includes
cadmium and chromium on a quarterly basis. In addition, the
1983 Court Order between PTPEM and L&RR, Inc., calls for surface
water monitoring. EPA believes that the selected remedy will
prevent the landfill from causing or contributing to AWQC
exceedances in the surface water. The groundwater monitoring
plan will confirm whether or not releases of contaminants from
the landfill are affecting the surface water after completion of
the remedy. If after completion of the remedy releases that
contribute to exceedances of AWQC are not prevented, further
remedial action will be taken acording to the provisions of
CERCLA and the NCP.
Finally, the existing landfill emissions from the uncapped vents
exceeded Rhode Islands Air Toxic Regulations and pose a potential
threat to public health. The selected remedy utilizes thermal
destruction to reduce the concentration of contaminants in the
landfill gas. With the results in the RI and the removal
efficiency of ^90-99.99%, the selected remedy wili achieve these
ARARs. Pilot "tests will be conducted during the design phase to
insure that the selected remedy achieves ARARs.
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ROD DECISION SUMMARY page 42
Action-Specific ARARst Table XII-3 lists the action-specific
ARARs which were common to all the containment alternatives.
(Alternatives 2-5). The table gives a synopsis of the
requirement. During the remedial action, the selected remedy
will comply with all relevant and appropriate RCRA requirements,
including the general closure performance standard (40 CFR S
264.111), and the monitoring, closure and post closure
requirements of 40 CFR Subparts F and G, the landfill closure
requirements of f 264.310, and the other relevant and appropriate
requirements of 40 CFR Subparts B-E, N and O. Because there is
presently no off-site release of groundwater contamination, the
relevant and appropriate portions of Subpart F are those dealing
with detection monitoring, 40 CFR § 264.90-.98. The selected
remedy will also comply with OSHA requirements such as those
which apply to working.with hazardous materials. Additionally,
wetlands remediation will be conducted according to the CWA and
the other requirements, listed in Table XII-1, associated with
dredging and restoring wetlands. Finally, State requirements
associated with transporting and utilizing municipal waste water
treatment sludge will be followed during establishment of
vegetation.
C. The Selected Remedial Action is Cost Effective
In the FS, a range of alternatives were developed for
remediating the landfill. Three of these alternatives,
Alternatives 3, 4 and 5, were equally protective and attained
ARARs. Once EPA has identified alternatives that are protective
and attain ARARs, EPA analyzes those alternatives to determine a
cost-effective means of achieving the cleanup. Alternatives 3
and 4 were similar in cost with a net present worth of $5,062,000
and $5,490,000, respectively. Alternative 5, however, was over
twice the cost of both of these alternatives with a net present
worth of $11,670,000. The selected remedy will utilize either
Alternative 3 or 4, the most cost effective of the alternatives
developed in the FS for remediating the landfill. During design,
if factors such as implementability influence the cost of these
alternatives, the most cost-effective one will be chosen.
For treating the landfill gas, three technologies were developed
in the FS: combustion, flaring and incineration. The costs of
each of these technologies were as follows: $1,300,000, $612,000
and $1,277,000, respectively. However, the estimated costs are
highly dependent on the cost of operating and maintaining the
system and could vary significantly due to such things as
equipment replacement costs due to corrosion. Section 121(a) of
CERCLA.requires EPA to take into account the total short- and
long-term costs, including the cost of maintenance for the entire
period during which such activities are required! Therefore,
before EPA can select the most cost effective technology from
these three, pilot tests are needed to assess the impacts of the
L&RR landfill gases on the operating costs of each system.
-------
SITE FEATURES
REQUIREMENTS
STATUS
Table XII-1
LOCATION-SPECIFIC ARARS
URR SITE
REQUIREMENT SYNOPSIS
APPLICATION FOR THE RI/FS
Landfill
Federal Regulatory
Requirement!
RCRA - Standard! for Owners and Relevant and
Operator! of Permitted Hazardous Appropriate
Waste Facilities
40 CFR 264.13-.16
General facility requirements
outline waste analysis, security
sttssures, and training require-
ments.
Because RCRA-listed hazardous waste* were placed
before 1980, RCRA Subtitle C requirements are
relevant and appropriate.
RCRA - Preparedness snd Prevent-
ion (40 CFR 264.30 - 264.37)
RCRA - Contingency Plan and
Emergency Procedures (40 CFR
264.SO - 254.56)
RCRA - Croundwater Protection
40 CFP 264.98
RCRA - Closure snd Post-closure
(40 CFR 264.110 - 264.120)
Relevsnt snd This regulation outlines safety
Appropriate equipment and spill-control
requirements for hazardous waste
•facilities. Part of the regulation
includea a requirement that
facilities be designed, maintained,
constructed, and operated so that the
possibility of an unplanned release
threatening human health or the
environment could be minimized.
Relevsnt snd This regulation outlines the
Appropriate requirements for emergency
procedures to be used following
explosions snd fires. This
•regulation also requires that
threats to public health and the
environment be minimized.
Relevant and Under this regulation,
Appropriate groundwater monitoring program
requirements are outlined.
Relevant.snd This requirement details the
Appropriate specific requirements for
closure and post-closure of
hszsrdous waste fscilities.
RCRA requirements were considered when
evaluating the effectiveness of the present
landfill, and will be further considered
when evaluating the design of potential
alternatives.
BCRA requirements were considered when
evaluating the effectivenss of the present
landfill, and will be further considered
when evaluating the design of potentisl
alternatives.
Croundwater SMnltoring must be considered
for each alternative. During alternatives
snalysis, the locstion and depth of
monitoring wells will be evaluated for
use in this monitoring program.
Long-tens monitoring and maintenance
portions of the regulstion will be
considered during remedial design.
12.87.ST
0001.0.0
CO
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Table XII-1 - continued
tOCATIM-SKClFIC ARAMs
un SITE
SITE FEATURES
REQUIREHEHTS
STATUS
sniopsis
APPLICATION FOR Ttt RI/FS
Federal Regulatory
Requirements
(continued)
RCRA - Landfills (40 CFR 264.300
24.339)
Relevant and
Appropriate
State Regulatory
Requirements
Fiab and Wildlife
Coordination Act
(16 U.S.C. Ml)
Rhode Island Rules for Solid
Waste Management Facilities
(RIGL 23 - It.9)
Applicable
Applicable
Rhode Island Hazardous Waste
Rules and Regulations (RIGL
23 • 18.9)
Relevant and
Appropriate
Wetlands. Trout Rrook
Federal Regulatory
Requirements
Clean Water Act (CWA) - 40 CFR
Section 404
State Regulatory
Requirementa
Rhode laland Freshwater Wetlands
law-Rhode laland General Lav
(RIGL) • Title 2 Chapter 1 (2-1)
Applicable
Applicable
Rhode laland Vater Quality Applicable
Regulations (RICL 46-12. 42-17.1,
42-35)
Covers design and operating
requirements, aa well aa
post-closure care options
for landfills. Closure and
post-closure care must be attained
in accordance with the outlined
disposal requirements.
This regulation requires sny
federal agency proposing to
•edify a body of water to consult
with the U.S. Fish and Wildlife
Services. This requirement is
addressed under CWA Section 404.
Outlines regulations for sanitary
landfills. Includes Initial
investigation, site grounduster,
operating and closure plans. Closure
requirements include 24 inches of
cover Material to be maintained on
all surfacea and faces of the land-
fill.
These requirements correspond to
RCRA hazardoua waste regulations.
Compliance with RCRA'will generally
achieve compliance with theae
regulations.
Regulates dischargee of dredged or
fill material into U.S. waters.
Regulstes snd preserves swamps,
marshes, and wetlands. Includes
maintaining capscity to support
wildlife snd set ss buffer xome for
flood conditions.
Regulates restoration, enhancement,
and preservation of stste waters.
The landfill cover must comply with require
ments for disposal closure. Performance
evaluation of eiisting cover has been
completed snd any potential remedial
alternatives must address areas of non-
compliance to attain disposal closure.
During the identification, screening, and
evaluation of alternatives, the effects on
wetlands will be evaluated. If an alterna-
tive would modify a body of water, U.S. Fisl
and Wildlife Services will be consulted.
Potential remedial alternativea must addres
sreas of landfill cover that do not meet
24-inch requirement, aa well aa any other
areaa of noncompliance.
Where RCRA regulations have jurisdiction,
these requirements will generally correapoo<
and be attained if more stringent than RCRA
Protection of the adjacent wetland. Applie
to sedimentation cauaed by erosion of land-
fill cap fill material.
Considerations such as reducing aedimentati<
to maintain the adjacent wetland'n water
storsge capsbilities will be addressed for
the RI/FS. < I
Potential remedial alternatives must addres>
this regulation because the adjacent wetlauf
is a state water.
1
I2.I7.ST
0002.0.0
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Table XII-1 - continued
LOCATION-SPECIFIC ARARS
L&RR SITE
SITE FEATURES REQUIREMENTS STATUS REQUIREMENT SYNOPSIS APPLICATION FOR THE RI/FS
State Regulatory Rhode Island Water Quality Applicable Water quality standards to be aiain- During identification, screening, and evalu-
Requireiaenla Standarda (RICL 46-12) tained in atate watera. Generally, a atioo of alternatives, BHPa will be conaidered
(continued) cheaiical-apecific ARAR, but applicable to control sedimentation to the wetland
aioce it provides physical criteria, cauaed by erosion of the landfill cover
such aa Best Management Practicea material.
(BHPa), to control aedimeotation.
Federal Criteria, Wetlanda Executive Order To be Prohibits the undertaking of new This regulation will be conaidered during th'e
Guidance, Adviaories (EO 11990) Conaidered construction in wetlands. RI/FS for uae in planning remedial actions.
to be Considered
EPA Guidance - "Covers for To be Outlinea the three components These design guidance criteria were used
Uncontrolled Hazardous Waste Considered that offer detailed guidance for for the preliminary cover assessment aa a
Sites" (EPA/540/2-85/002) the design of a cover system which baseline for determining the compliance of
will achieve the specified per- the existing cover with RCRA requirements.
formance standards of RCRA landfill These criteria will also be conaidered during
covera. alternative development and evaluation.
I
in
12.B7.5T
nnni i n
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quiremeat Type
Requirement
Table XII-2
COMICAL-SPECIFIC ARARS AND CRITERIA, ADVISORIES. AMD GUIDANCE
LUUt Sin
Requirement Synopaia
consideration in the m/rs
deral Regulatory
quiremeata
SDWA • Maiimum Contaminant Level•
(MCLa) (40 CFR Ul.ll - 141.16)
deral Criteria,
Iviaorlea, aad
idaace
NCLa have been promulgated for a number of
organic aad inorganic contaminanta.
Theae level* regulate the concentration of
contaminants in public drinking water
supplies, but may alao be considered relevant
and appropriate for groundvater aquifera
used for drinking water.
Wfcen tlM risk* to kwaaa nealtk due to coMtavption
of groondwatar wen aaaeaaed, contaainant
cencentrationa were compared to their NCLa. Only
iron and aanganeae eiceeded tneir aecondary
levels. Secondary atandarda are not health-
baaed; therefore, iron and annganese are not
considered contaminants of concern.
Federal AoMent Water Quality
Criteria (AWQC)
Federal AUQC are health-baaed criteria
that have been developed for 95
carcinogenic and noncarcinogenic compounds.
AWQC wert conaldered in characterizing riaka to
human health and aonatlc organiama dne to
contaminant concentrationa in the wetlanda and
Tront Irook. lecawae thia water ia not naed aa a
drinking water aource. the criteria developed for
aquatic ornaoiama were un«-«l.
Health Adviaorles (EPA Office of
Drinking Water)
EPA Riak Reference Doeea (RfDa)
1 ' f ?
•
EPA Carcinogen Asaessment Croup
Potency Factora
Health adviaoriea are eatimatea of risk due
to consumption of contaminated drinking
water; they conaider noncarcinogenic
effecta only.
RfDa are dose levela developed by
EPA for noncarcinogenic effecta.
Potency factora arc developed by EPA
from Health Effecta Aaaeaamenta or
evaluation by the carcinogen assessment
group.
Health adviaoriea were considered for contaminanta
in groundwater that may be used for drinking
water.
EPA RfDa were uaed to characterise riaka dtte to
expoauro to groundwater comtaminanta. They were
conaidered for noncarcinogena including 2-butanone
' lead.
EPA carcinogenic potency factora were uaed to
compute the individual incremental cancer riak
resulting from expoamre to araenie.
12.17.
0001.0
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Table XII-2 - continued
CHEMICAL-SPECIFIC ARARs AND CRITERIA, ADVISORIES, AND GUIDANCE
L&RR SITE
Requirement Type Requirement Requirement Synoptit Consideration in the RI/FS
Acceptable Intake - Chronic (AIC) AIC and AIS values are developed fro* RfDa AIS and AIC values were used to characteriie the
and Subchronic (AIS) - EPA Health and HEAa for noncarcinogenlc compounds. risks due to several noncarcinogens in ground-
Assessawnt Documents water and aurfsce water. These noncarcinogens
include 2-butanone, trans-1,2-dichloroethene,
1,1-dichloroethane, lead, and zinc.
Rhode Island ' Rhode Island Water Quality Standards Freshwater guidelines were developed for Water quality stsndsrds were compared to AWQCs
Criteria, Advisories, (RIGL 46-12) several organics snd inorganics. for compounds such as toluene and araenic.
and Guidance
Rhode Island Air Toxics Regulation Esiissions standards developed for traditional Air modeling results were compared to these
and nontraditional stationary sources regulations when airborne risks were characterized.
including landfill vents.
*
12.87.99T
0002.0.0
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TablS XII-3
ACTION-SPECIFIC AMAHS
LANDFILL AND RESOURCE RECOVERY
REQUIRMKTS
STATUS
REQUIREICNT STNOFSI8
Federal Regulatory
Requirements
ROW - Subpart I:
Standards
General Facility
RCRA - Subpart C: Preparedness
and Prevention (40 CFR 264.30 -
264.37)
RCRA - Subpart D: Contingency
Flan and Emergency Procedures
(40 CFR 264.SO - 264.56)
Relevant and General facility requirements
Appropriate outline waste analysis, security
measures, and training require-
ments.
Relevant and This regulation outlines safety
Appropriate equipment and spill-control
requirements for hazardous waste
facilitiea. Fart of the regulation
includes a requirement that
facilities be designed, maintained,
constructed, and operated to minimize
the possibility of an unplanned release
that could threaten human health or
the environment.
Relevant and This regulation outlines the
Appropriate requirements for emergency
procedures to be used following
explosions and firea. This
regulation also requires that
threats to public health and the
environment be minimiied.
RCRA - Subpart F: Releases From Relevant aod
Solid Waste Management Units Appropriate
Under this regulation,
groundwater monitoring progri
requirements are outlined.
RCRA - Subpart C: Closure and Relevant and
Post-Closure (40 CFR 264.110 - Appropriate
264.120)
This requirement details the
specific requirements for
closure and post-closure of
hazardous waste fscilities.
1.M.11IT
0.0
CD
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REQUIREMENTS
'able XII-3 - continued
ACTION-SPECIFIC ARARS
LANDFILL AND RESOURCE RECOVERY
STATUS REQUIREMENT SYNOPSIS
Federal Regulatory
Requirementt
(continued)
RCRA - Subpm N: Landfills
(40 CFR 264.300 - 264.339)
Relevant and
Appropriate
RCRA - Subpart 0: Incinerators
(40 CFR 264.340 - 264.599)
Clean Water Act (CVA) (Section
404) .
Clean Air Act - National Air
Quality Standarda for Total
Suspended Participates
(40 CFR SO.6 - 50.7)
OSHA • General Industry Standards
(29 CFR 1910)
Relevant-and
Appropriate
Applicable
Relevant and
Appropriate
Applicable
OSHA - Safety and Health Standards Applicable
for Federal Service Contracta
(29 CFR 1926)
OSHA - Recordkeeping, Reporting, Applicable
and Related Regulations
(29 CFR 1904)
DOT Rules for the Transportation Applicable
of Hazardous Haterials
i(49 CFR 107, 171.1 - 171.500)
Fish and Wildlife Applicable
Coordination Act
(16 U.S.C. 661)
Covers design and operating
requirements, as well as
post-closure care options
for landfills. Closure and
post-closure care must be attained
in accordance with either the
outlined disposal requirement* or
by the site-specific alternate
method.
This regulstion specifies the per-
formance standards, operating
requirements, monitoring, inspection,
and closure guidelines of any
incinerator burning hazardous waste.
Regulates discharges of dredged or
fill material into U.S. waters.
This regulation specifies maximum
primary and secondary 24-hour
concentrations for particulate'
matter.
This regulstioo specifies the 8-hour,
time-weighted average concentrations
for various organic compounds.
This regulation specifies the type of
safety equipment and procedures to be
followed during site remediation.
This regulation outlines the record-
keeping and reporting requirements for
'an employer under OSHA.
This regulation outlines procedures
for the packaging, labeling,
manifesting, and transport of
hazardous materials.
This regulstion requires any
federal agency that proposes to
modify • body of water to consult
with the U.S. Fish and Wildlife
Services. This requirement is' '<
addressed under CVA Section 404. '
n
a.
1.88.HIT
0007.0.0
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Table XlI-3 - continued
ACTION-SPECIFIC ARAKS
LANDFILL AND RESOURCE RECOVERY
REQUIRCHENTS
STATUS
REQUIREMENT SYNOPSIS
State Regulatory
Requirements
Rhode Island Rules for Solid
Watte Management Facilities
(November 1, 1912)
Rhode Island Natardous Watte
Rules aid Regulations
(June 21, 1984)
Rhode Island Freshwater Wetlands
Law - Rhode Island General Law
(RICL) - Title 2 Chapter 1 (2-1)
Rhode Island Water Pollution
Control Law (RICL 46 • 12)
Rhode Island Water Quality
Regulations (RIGL 46-12, 42-
17.1, 42-35)
Rhode Island Water Quality
Standards (RICL 46-12)
'Rhode Inland Air Pollution
Control Regulations
(August 2, 1967)
Rhode Island Air Pollution
Control Act (23-23, 23-23.1)
Applicable Outlines regulations for sanitary
landfills. Includes initial
. investigation, site groundwater, and
operating and closure plans. Closure
requirements include 24 'inches of
cover Mterisl to he Maintained on
•11 surfaces and faces of the land-
fill.
Relevant and These requirements correspond to
Appropriate RCRA hazardous waste regulations.
Compliance with RCRA will generally
achieve compliance with these
regulations.
Applicable Regulates and preserves swamps,
marshes, and wetlands. Includes
maintaining capacity to support
wildlife and act as buffer zone for
flood conditions.
Relevant and These requirements correspond
Appropriate to CWA regulations. Compliance
with the relevant sections of
CWA will generally achieve
compliance with these requirements.
Applicable Restoration, enhancement, and pre-
servation of state waters.
Applicable Water quality standards to he main-
tained in stste waters. Generally, •
chemical-specific ARAR, hut applicable
because it provides physical criteria
such as Rest Nanagement Practices
(RHPs) to control sedimentation.
Relevant and Details the requirements, limitations,
Appropriate and exemptions of state air emission
regulations for specified substances.
Relevant and Outlines the policy of preserving,
Appropriate protecting, and improving the air
resources of Rhode Island. ;
jlllT
(0.0
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Table XII-3 - continued
ACTION-SPECIFIC ARAKS
LANDFILL AND RESOURCE RECOVERY
REQUIREMENTS
STATUS
REQUIREMENT SYNOPSIS
State Regulatory
Requirementt
Federal Criteria.
Guidance, Advisories
to be Considered
Rhode Island Rules and Applicable
Regulations Pertaining to the
Disposal, Utilization, and
Transportation of Waitewaler
Treatment Facility Sludge.
(September 1985)
Rhode Island Air Toiic Applicable
Regulations (Regulation No. 22)
Wetlands Executive Order To be
(EO 11990) Considered
EPA Guidance Document - "Covert To be
for Uncontrolled Hazardous Waste Considered
Sites" (EPA/540/2-85/002)
Thla requirement applies to the
diaposal of sludge by land
application or incorporation of
the sludge into the soil for
silvicultural purposes.
Liaiits the emission of listed
substances fro» stationary sources.
Prohibits the undertaking of new
construction in wetlands, which
includes dredging.
Outlines the three components
that offer detailed guidance for
the design of a cover system which
will achieve the specified per-
formance standards of RCRA landfill
covers.
in
1.88. HIT
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ROD DECISION SUMMARY page 52
D. The Selected Remedy Utilizes Permanent Solutions and
Alternative Treatment Technologies or Resource
Recovery Technologies to the Maxima Extent
Practicable
During the FS, EPA developed one alternative that was considered
a permanent solution, Alternative.6. This alternative consisted
of excavating the landfill wastes; incinerating the removed
wastes at an off-site, RCRA compliant facility; and, wetlands
sediment removal and disposal. However, this alternative was
eliminated from further consideration during the initial
screening process for a number of reasons. The significant
reasons are summarized below.
First, significant public health and environmental risks would be
posed by its implementation. Excavation of the wastes is likely
to release VOCs and particulates to the atmosphere, including
asbestos and metal fibers known to be disposed at the Site,
creating both on-site and off-site risks due to inhalation.
Second, because the area of hazardous waste cannot be clearly
defined, it was assumed that all of the landfill wastes must be
removed and treated. It would take approximately 90 years to
implement this alternative. Third, incinerator capacity nation
wide is insufficient for the quantity of wastes in the landfill
and extremely costly. The estimated cost was $2.6 billion
dollars. A more detailed discussion of the reasons for
elimination of the excavation and treatment alternative is
presented in Appendix AA of the RI/FS Report.
In conclusion, the long term uncertainties associated with the
selected remedy, a land disposal remedy, are much less than the
risks posed, the implementation problems and the costs associated
with implementing a permanent remedy. Furthermore, the selected
remedy includes Site monitoring to insure that it remains
protective. Therefore, the selected remedy utilizes permanent
solutions and alternative treatment to the maximum extent
practical.
The selected remedy identifies three technologies to treat the
landfill gas. One of these technologies, combustion is
considered a resource recovery technology because it generates
electricity while destroying the hazardous constituents in the
gas. This factor may reduce the costs of implementing this
technology. EPA will consider this factor when selecting the gas
treatment technology during the design phase.
E. The Selected Remedy Partially Satisfies the Preference
for Treatment as a Principal Element
A
As stated above, excavation and treatment of the source material
is impractical, involves unacceptable risks and is not cost
effective. The selected remedy has three components: upgrading
the landfill closure; treating the landfill gas and monitoring
the Site. The second component, treating the landfill gas, will
-------
ROD DECISION SUMMARY page 53
'source Recovery Site :
reduce the volume, toxicity and nobility of the hazardous
substances in the gas and the risks posed from exposure.
Therefore, the gas treatment component partially satisfies the
preference for treatment as a principal element of the remedy.
XIII. STATE ROLE
The Rhode Island Department of Environmental Management (RIDEM)
has reviewed the various alternatives presented in the
Feasibility Study and EPA's preferred alternative as presented in
the Proposed Plan. The State has also reviewed the Remedial
Investigation and Feasibility Study to determine if the selected
remedy is in compliance with applicable or relevant and
appropriate State environmental laws and regulations. The RIDEM
concurs with the components of the selected remedy for the L&RR
•Site which are consistent with the 1983 Court Order and Consent
Order and Agreement between RIDEM and L&RR, Inc. In regards to
the additional components, RIDEM recognizes that they are not
inconsistent with the 1983 Court Order and provide additional
protection. RIDEM also recognizes that EPA's selected remedy,
are required by CERCLA and the NCP. A copy of the declaration of
concurrence is attached as Appendix C.
-------
APPENDIX A
RESPONSIVENESS SUMMARY
Landfill i Resource Recovery Site
-------
LANDFILL t RESOURCE RECOVERY SITE
Responsiveness Summary
TABLE OF CONTENTS
Contents page
Preface 1
I. RESPONSIVENESS SUMMARY OVERVIEW 2
A. Site Background 2
B. Overview of Remedial Alternatives and EPA's
Proposed Plan 2
1. Remedial Alternatives 3
2. Gas Treatment Technologies 3
3. EPA's Proposed Plan 4
C. Overview of Comments Received During the Public
Comment Period 4
1. Overview of Comments from Community Members . 4
2. Overview of Comments from RIDEM 5
3. Overview of Comments from the Potentially
Responsible Parties (PRPs) 5
II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS .... 6
III. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT
PERIOD AND EPA RESPONSES TO COMMENTS 7
PART 1. COMMUNITY COMMENTS 7
A. CONCERNS REGARDING THE RESPONSIBLE PARTY . 7
B. GROUNDWATER MONITORING 9
C. . MISCELLANEOUS 10
PART 2. RIDEM COMMENTS 11
A. TECHNICAL CONCERNS REGARDING EPA
INVESTIGATIONS AND THE PROPOSED PLAN . . 11
B. ALTERNATIVE PREFERENCE 16
PART 3. POTENTIALLY RESPONSIBLE PARTIES COMMENTS ... 17
A. TECHNICAL CONCERNS 17
B. LEGAL CONCERNS REGARDING EPA
INVESTIGATIONS AND THE PROPOSED PLAN . . 40
IV. REMAINING CONCERNS 50
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RESPONSIVENESS SUMMARY page 1
Landfill t Resource Recovery Site
Preface
The U.S. Environmental Protection Agency (EPA) held a public
comment period from July 20, 1988 through September 2, 1988 to
provide an opportunity for interested parties to comment on*EPA's
Remedial Investigation (RI), Feasibility Study (FS), and Proposed
Plan for the Landfill and Resource Recovery Site (L&RR) in North
Smithfield, Rhode Island. On August 10, 1988, EPA held an
informal public hearing to provide an opportunity for the public
to submit oral comments to EPA.
The purpose of this Responsiveness Summary is to document
EPA's responses to the comments and questions raised during the
public comment period. EPA considered all of the comments
summarized in this document prior to the Agency's final selection
of a remedy for the L&RR Site.
This Responsiveness Summary is organized into the following
sections:
I. Responsiveness Summary Overview — This section briefly
outlines the history of the Site and the remedial
alternatives evaluated in the FS, including EPA's preferred
alternative. This section also includes an overview of the
comments that EPA received during the public comment period.
II. Background on Community Involvement and Concerns — This
section provides a brief history of community interests and
concerns regarding the L&RR Site.
III. Summary of Comments Received and EPA Responses — This
section provides a detailed summary of both the written and
oral comments received during the public comment period and
provides EPA's responses to these comments. Part 1
summarizes comments received from citizens and other
community interest groups. Part 2 summarizes comments from
the Rhode Island Department of Environmental Management
(RIDEM). Part 3 summarizes comments received from
potentially responsible parties (PRPs). All of the parts
are arranged by subject matter.
IV. Remaining Concerns — This section describes concerns that
will continue to be addressed by EPA during design and
implementation of the selected remedy.
Attachment A — This attachment includes a list of the
community relations activities conducted by\RIDEM and EPA
during the remedial history of the Site.
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RESPONSIVENESS SUMMARY page 2
I. RESPONSIVENESS SUMMARY OVERVIEW
A. Site Background
The L&RR Sit« is an inactive landfill that covers
approximately 28 acres of a 36 acre parcel of land on Oxford
Turnpike in North Smithfield, Rhode Island. The landfill was
reportedly used from 1927 until 1985 for the disposal of
commercial, industrial, and residential waste. Between 1977 and
1979, the landfill reportedly accepted hazardous waste. From
1974 to 1985, the landfill was operated by Landfill and Resource
Recovery, Incorporated (L&RR, Inc.), the current property owners.
In 1979, L&RR, Inc. covered what they defined as the
hazardous waste area of the landfill with a synthetic cover. The
Site was added to the Superfund National Priorities List (NPL), a
list of the nation's hazardous waste sites eligible to receive
federal Superfund monies for cleanup, in 1982.
In 1985, the landfill owners ceased accepting wastes and *
began closing the landfill as specified in plans included in a
1983 Court Order and Consent Order and Agreement, referred to in
the remainder of this document as "the 1983 Court Order", between
RIDEM and L&RR, Inc. As part of this process, the landfill
owner covered approximately 80% of the landfill with another
synthetic cover and soil to support vegetation.
In 1988, EPA completed a comprehensive study at the L&RR
Site called a Remedial Investigation/Feasibility Study (RI/FS).
The RI was conducted to define the nature and extent of
contamination in the groundvater, air, and nearby surface waters.
The FS was conducted to identify and evaluate remedial
alternatives that would be effective in addressing contamination
at the Site. The Record of Decision (ROD) is written at the end
of the RI/FS phase of the Superfund process and describes EPA's
selected remedy as well as EPA's rational for selection.
B. Overview of Remedial Alternatives and EPA's Proposed
Plan
Using the information gathered during the RI, EPA identified
three general objectives for the Site: 1) treat the landfill gas
to reduce the potential public health risks from exposure to the
landfill vent emissions; 2) restore the wetlands that have been
affected by erosion from the landfill and prevent future adverse
impacts caused by erosion; and 3) close, maintain, and monitor
the landfill so that it is protective of public health and the
environment and complies with federal and state regulations.
After identifying site-specific objectives, EPA developed
and conducted a detailed analysis of five remedial alternatives
and three gas treatment technologies for the Site. The remedial
alternatives and the gas treatment technologies analyzed for the
L&RR Site in the FS are summarized in the following sections.
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RESPONSIVENESS SUMMARY page 3
Landfill & Resource Recovery Site
1. Remedial Alternatives
No Action fAlternative 11. This alternative would consist solely
of long-term groundwater monitoring.
.Vegetation Establishment (Alternative 2). This alternative would
involve upgrading the existing landfill closure by covering the
landfill with 24 inches of soil and planting vegetation. This
alternative would also include the following components:
removing sediments from and reseeding the wetlands; installing a
fence around the site; developing a landfill post-closure plan;
upgrading the surface water runoff management system; and
installing a passive gas collection system.
Synthetic Cover Installation/Slope Stabilization (Alternative 31.
This alternative would include all of the components of
Alternative 2 but would also involve stabilizing the steeply .
sloping sides of the landfill in the northeast portion of the
Site by grading the slope and adding a terrace. Then a
synthetic cover would be installed over the stabilized slope.
Additional soil would be placed on the synthetic cover and
vegetation would be established. In addition, this alternative
includes installing a gas collection and treatment system rather
than the passive gas collection system in Alternative 2.
Synthetic Cover Installation/Slope Flattening fAlternative 41.
This alternative is identical to Alternative 3 except the steep
slopes would be stabilized by flattening them to a greater
degree.
RCRA Cover Guidance (Alternative 51. This alternative would
involve flattening and covering the steep sides of the landfill
as well as placing a clay barrier, drainage layers and a new
vegetative cover over the entire landfill. This alternative was
developed according to an EPA guidance document for constructing
covers for hazardous waste sites. Alternative 5 also would
include all of the other components included in Alternatives 3
and 4 and gas treatment.
2. Gas Treatment Technologies
Combustion. Combustion would entail burning the landfill gas in
an internal combustion engine to produce electricity as a useful
by-product.
Flaring. The flaring process would burn the landfill gas in a
manner similar to combustion but does not produce electricity.
Incineration. Incineration would burn landfill gases at high
temperatures in a closed reaction chamber. '<
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RESPONSIVENESS SUMMARY page 4
3. EPA*s Proposed Plan
EPA*s selection of a preferred alternative, as outlined in
the Proposed Plan, was the result of a comprehensive evaluation
and screening process. EPA's Proposed Plan included the
following three components:
o The existing landfill closure would be upgraded to
effectively contain the wastes. EPA selected
Alternatives 3 and 4 as the Agency's preferred
alternatives for this component of the Proposed Plan.
EPA will choose one of the two alternatives during the
remedial design phase of the project after site-
specific tests have been conducted;
o A landfill gas collection and thermal destruction
system would be constructed to treat the landfill gas.
EPA has chosen three thermal destruction technologies
for treatment of the landfill gas. The specific
technology will be selected by EPA during the design
phase of the project, when specific information
regarding the performance of each technology is
available; and,
o The groundwater and air would be monitored on a regular
basis to ensure the Site remains protective of public
health and the environment.
For more details on the FS alternatives and EPA's preferred
alternatives, refer to the Proposed Plan.
C. Overview of Comments Received During the Public Comment
Period
EPA received comments from three community members, RIDEM,
technical and legal representatives of L&RR, Inc., and General
Dynamics. In Section III of this document, these comments are
summarized and EPA responses are provided. A general overview of
the comments received is provided below.
1. Overview of Comments from Community Members
Community members, including a representative of Protect Our
Water, a local citizens' group, indicated general support of
EPA's Proposed Plan. However, each commenter expressed serious
concern about the possibility that the landfill owner might
operate the landfill gas treatment system. Area residents also
expressed concern that the groundwater monitoring wells are not
close enough together to ensure that a contaminant plume would be
detected. Community comments and EPA responses ;are provided in
Section III, Part 1 of this document.
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RESPONSIVENESS SUMMARY page 5
Landfill & Resource Recovery Site
2. Overview of Comments from RIDEM
In general, RIDEM recommends that EPA consider the
implementation of the closure measures outlined in the 1983
Court Order between RIDEM and L&RR, Inc., combined with wetlands
restoration as the remedy for the L&RR Site. RIDEM stated that
EPA should provide additional justification to support the need
for a synthetic cover on the uncovered portion of the landfill.
RIOEM's comments and EPA responses are provided in Section III,
Part 2 of this document.
3. Overview of Comments from the Potentially
Responsible Parties (PRPs)
Wehran Engineers, Inc., and Dean Temkin, Esq., submitted
extensive comments on behalf of the owner and operator of the
L&RR Site. Both commenters stated their strong belief that the
1983 Court Order between RIDEM and L&RR, Inc., includes
appropriate and adequate measures to ensure protection of public
health and the environment, and that no additional remedy is
needed. Other general issues addressed by the commenters
included the following:
o The appropriateness of the risk assessment exposure
assumptions-relating to the landfill vent emissions;
o The validity of the model used by EPA to measure the
performance of the landfill;
•
o EPA's interpretation of which federal and state regulations
must be complied with; and,
o The appropriateness of including wetlands remediation as
part of a Superfund action.
The commenters also included clarifications of the Site
history, particularly relating to the 1983 Court Order between
RIDEM and L&RR, Inc. PRP comments and EPA responses to these
comments are provided in Section III, Part 3 of this document.
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landfill £ Resource Recoverv Site
II. BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS
According to Site records, community concern about and
interest in the L&RR Site has been moderate to strong since the
aid 1970s, when trucks travelling to and from the landfill-caused
most neighbors to become aware of the landfill for the first
time. In response to complaints about L&RR and other hazardous
waste sites in the area, two citizens groups formed — Protect
Our Waters (POW) and Saving the Environment of North Smithfield
(SENS). These groups were very active in the late 1970s,
coordinating media events, disseminating information about the
sites, and organizing rallies. The groups repeatedly sought to
close L&RR. Although the efforts met with little immediate
success, POW was instrumental in the passage of two state laws to
ban hazardous and solid waste facilities from being located over
aquifers.
In 1978, the North Smithfield Town Council formed a task
force on hazardous waste that included members of POW and SENS.
One of the goals of the task force Was to build a case to
convince the state legislature, the courts, RIDEM, and EPA to
take some type of action at L&RR. In 1979, when the hazardous
waste portion of the landfill was closed, the task force
disbanded and POW and SENS became less active. At present,
community members including members of POW remain very interested
in area environmental issues and have expressed concerns about
preventing risks to public health from exposure to hazardous
waste, protecting the Slatersville Reservoir, and managing
community growth and development.
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Landfill & Resource Recoverv Site
III. SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT
PERIOD AND EPA RESPONSES TO COMMENTS
This Responsiveness Summary addresses the comments received
by EPA on the Remedial Investigation (RI), Feasibility Study
(FS), and Proposed Plan for the Landfill and Resource Recovery
Site (L&RR Site) in North Smithfield, Rhode Island. During the
public comment period, EPA received written comments from six
parties and the Rhode Island Department of Environmental
Management (RIDEM). There were two oral comments given at the
public hearing held on August 10, 1988. Copies of the hearing
transcript are available at the information repository located in
the Municipal Annex Building in North Smithfield and at the EPA
Records Center, 90 Canal Street, in Boston, Massachusetts.
In Part 1 of this section, comments received from the
community are summarized and EPA responses are provided. Part 2
summarizes and provides EPA responses for comments received from
RIDEM. Part 3 summarizes and provides EPA responses to comments
submitted on behalf of Potentially Responsible Parties (PRPs).
PART 1. COMMUNITY COMMENTS
A. CONCERNS REGARDING THE RESPONSIBLE PARTY
Several commenters (area residents and members of Protect
Our Water) raised specific concerns regarding the past and future
activities of the landfill owner.
1. Comment;
Each of the four written comments EPA received from
community members referred to a newspaper article stating
that the landfill owner wants to burn the landfill gas and
create electricity for sale. Members of Protect Our Water
expressed specific concern that the gas treatment system
would be operated for profit by the landfill owners, stating
that the landfill owners have never evidenced concern for
public health and welfare. The commenters stated further
that any profit gained from selling electricity generated
from the landfill should be returned to the government or
used toward the closure of the Site.
EPA Response;
The selected remedy utilizes thermal destruction to treat
the landfill gas. EPA will choose one of the following
three thermal destruction technologies during the design
phase; combustion, flaring or incineration.\ All three burn
the gas to destroy the hazardous constituents but only one
has the potential to produce electricity, combustion. This
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RESPONSIVENESS SUMMARY page 8
Ijtndifi.il ft Resource Recovers
technology may not be a profit making technology due to the
operation and maintenance costs. Pilot tests will be
conducted during the design phase to provide EPA with
information necessary to identify which of the three
technologies is protective and cost effective.
EPA will negotiate with all of the potentially responsible
parties, including the site owners, to implement the
remedy. If the responsible parties agree to implement the
remedy, they must implement the remedy in accordance with
the Comprehensive Environmental Response and Liability Act
(CERCLA) which requires it to be protective of public health
and the environment. EPA will monitor the design and
construction of the remedy to insure that it is protective.
Furthermore, the selected remedy includes an air monitoring
program to insure that during operation, the selected remedy
remains protective.
2. Comment !
Protect Our Water stated their concern with the landfill
owners being the operators and maintainers of a gas
collection system that is necessary to safeguard air quality
and asked the following specific questions regarding the
proposed gas treatment system:
1. Which of the three gas collection systems proposed in
the EPA report is the system of choice for the
situation as it exists at L&RR? We ask this noting
that only combustion, of the three systems discussed,
makes the gas available for sale and also noting that
incineration is the most efficient in the destruction
of contaminants.
2. Who will determine if the system is properly operating?
3. Who will maintain the system?
4. What will happen if the system becomes unprofitable?
5. Who will determine when and if the system should be
discontinued?
EPA Response;
As stated in response to comment |2, EPA will select the
specific gas treatment technology during the design phase,
after pilot tests are conducted. A monitoring plan will be
implemented to insure that the system is protective. EPA
and RIDEM will review the monitoring data on a periodic
basis to insure that the system remains protective.
If the responsible parties agree to implement the remedy,
they will be responsible for maintaining the system. The
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RESPONSIVENESS SUMMARY page 9
Landfill & Resource Recovery Site
selected remedy includes a post-closure plan which
specifies routine inspections and maintenance requirements.
The system will be operated as long as necessary to reduce
the risks from exposure to the landfill gas. EPA will
decide when the system is no longer needed. EPA doubts that
any of the systems will be profitable because of operation
and maintenance costs. However, this issue will not
influence EPA's decision on whether treatment is needed.
B. GROUNDWATER MONITORING
1. Comment;
Protect Our Water and a community resident expressed their
concern with the great distances between monitoring wells in
place at the Site. In particular, the group is concerned
about protecting the Slatersville Aquifer, which provides
one third of the town's water supply. The organization
recommended that EPA install three additional monitoring
wells in specific locations. They stated that the estimated
$30,000 cost to install the three additional wells is
relatively -ggmTi in comparison with the $6 million EPA
proposes to spend to implement the Proposed Plan.
EPA Response:
A number of factors must be considered when establishing a
network of groundwater monitoring wells at a site.
Presently there are 14 groundwater monitoring wells
. installed around the perimeter of the Site. Nine of these
wells were installed by the present Site owner. After
reviewing hydrologic and geologic information for the Site,
EPA installed five additional monitoring wells during the
RI/FS to gather information to characterize contamination at
. the Site. In response to this concern, EPA reviewed once
again all the data collected to date and established a
revised long-term groundwater monitoring plan which is
outlined in the Record of Decision (ROD). This plan
requires a new cluster of wells. This cluster will have two
wells and will be located between monitoring well clusters
CW-6 and CW-7. The specific location of this cluster will
be decided during the design phase. Given the geologic
conditions at the Site, this monitoring well network will
identify a contaminant groundwater plume migrating from the
site.
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RESPONSIVENESS SUMMARY page 10
Landfill & Resource Recovezv Site
C. MISCELLANEOUS
1. Commentt
One resident stated his belief that the contamination'at the
Site should be removed and neutralized, minimizing the
threat of spreading contamination in the future.
EPA Response;
During the Feasibility Study, EPA developed an alternative
that would permanently destroy the source of contamination
at the Site. This alternative consisted of excavating the
wastes and treating them in an incinerator. This
alternative was not chosen as the selected remedy for the
following reasons. First, significant public health and
environmental risks would be posed by its implementation.
Excavation of the wastes is likely to release volatile
organic compounds (VOCs) and particulates such as asbestos
into the atmosphere creating on-site and off-site risks from
inhalation. Second, since the location of the hazardous
wastes is unknown, EPA assumed that all of the wastes must
be removed and treated. This would take approximately 90
years to implement. Third, incinerator capacity nation wide
is insufficient for the quantity of wastes available.
Finally, this alternative would cost nearly 2 billion
dollars to implement.
2. Comment:
One citizen took exception to an EPA report that stated that
the landfill accepted waste for disposal since .1927. The
commenter stated that he is able to produce evidence
disproving the date in question.
EPA Response;
It was stated in the RI/FS Report that wastes had reportedly
been accepted for disposal at the Site since 1927. This
information was based on discussions with past owners and
other people with historical knowledge of the Site. EPA
would welcome any information regarding historical waste
disposal activities at the Site.
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RESPONSIVENESS SUMMARY page 11
Landfill & Resource Recovery Site
PART 2. RIDEM COMMENTS
A. TECHNICAL CONCERNS REGARDING EPA INVESTIGATIONS AND THE
PROPOSED PLAN
Formal comments from the State of Rhode Island were
submitted by the Department of Environmental Management (RIDEM).
1. Comment:
RIDEM has questions about the runoff and infiltration
quantities projected from the modelling of the existing
cover system at the landfill. The Department requests a
more detailed explanation of the modelling procedures,
capabilities, and results. RIDEM is interested in how the
data influences EPA's selection of the remedy. In addition
to the RIDEM comment, Wehran Engineering, the consultant for
L&RR, Inc., also commented on the appropriateness of the
methods used by EPA to predict the infiltration and runoff
quantities. The response to this comment is presented in
Part 3.A.2.
EPA Response;
Two methods were utilized to assess infiltration in the
landfill and specifically the area without a synthetic
cover, the Hydrogeologic Evaluation of Landfill Performance
(HELP) mpdel, Version I, and the Thornthwaite and Mather
water balance model as republished by Fenn, Hanley and
DeGeare, in 1977. Both models are designed to predict
infiltration based on, among other things, rainfall and
runoff characteristics and both are controlled by
assumptions and input parameters. Its also important to "
note that both methods give approximations based upon
impirical data and reasonable assumptions.
In response to Wehran's comments, EPA reviewed all of the
methods utilized and the results obtained. It was
interesting to note that Wehran Engineering calculated two
different results using the same model. In 1983, Wehran
performed a water balance for the uncovered area of the
landfill using the method of Thornthwaite as modified by
Fenn and calculated an infiltration of 19.3 inches/yr.
Using this same method in their September 1988 comments on
EPA's RI/FS, Wehran calculated a value of 6.8 inches/yr.
These differences demonstrate the variation in infiltration
that can result when different assumptions .are used with the
method. Using the HELP Model, EC Jordan, EPA's consultant,
calculated infiltration as 27.64 inches/yr. In response to
Wehran's comment, EC Jordan recalculated infiltration using
the Thornthwaite method as modified by Fenn with similar
assumptions as those utilized in the HELP model
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RESPONSIVENESS SUMMARY page 12
calculations. In this instance, Jordan's calculations
resulted in an infiltration of 16 inches/yr (See Memo from
EBASCO dated September 26, 1988 in the Administrative
Record).
EPA agrees with the Wehran comment that the HELP model is
limited in its ability to accurately represent slopes
greater than 10%. The HELP model represents a conservative
approach which has been utilized at many sites with slopes
steeper than 10%. EPA further agrees that the Thornthwaite
method, as modified by Fenn, is a more appropriate method
for representing the infiltration at the L&RR Site.
However, the Thornthwaite method, as modified by Fenn,
results in a range of values for infiltration between 6.8
in/yr and 19.3 in/yr. As Wehran points out in their
comment, the results are strongly influenced by the
assumptions and in particular the assumed runoff
coefficient. Without site-specific information and
information concerning the input assumptions, made by Wehran,
EPA cannot evaluate which of the approximations calculated
is a closer representation of the actual field conditions at
the L&RR Site.
Based on a review of EC Jordan's assumptions and results,
EPA believes that the actual infiltration in the uncovered
area could realistically be in the range between 6.8 in/yr
and 19.3 in/yr which represents 185,000 gallons/acre/yr and
524,000 gallons/acre/yr, respectively. The maximum
infiltration calculated for the rest of the landfill, which
has a synthetic cover as part of the cover, system, was
estimated to be 7,690 gal/acre/yr. Given the long-term
uncertainties associated with land disposal and the lack of
information regarding the location of the wastes, the amount
and types of hazardous wastes disposed and the hydrologic
flow in the landfill, EPA finds this range of infiltration
in the uncovered area unacceptable. In order to meet the
objective of the objectives of CERCLA, to protect human
health and the environment and to meet applicable relevant
and appropriate requirements (ARARs), the synthetic
impermeable membrane is necessary on the uncovered area of
the landfill.
2. Comment
RIDEM requests that EPA consider alternative groundwater
monitoring programs that would provide adequate monitoring
but include flexibility in the frequency and/or parameters
chosen, dependent on the trends in analytical data
collected.
\
EPA Response;
EPA established a groundwater monitoring program in the ROD
that was different from the ones discussed in the RI/FS
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RESPONSIVENESS SUMMARY
Landfill & Resource Recovery Site
page 13
Report. The monitoring plan is outlined below and nay be
revised based on trends in analytical data.
Wells:
MW-101
MW-102 A,B
MW-103 A,B
MW-104 A,B**
CW-5 A,B,C
CW-6 A,B,C
CW-7 A,C*
(15 wells)
* EPA does not think that CW-7B is needed.
** MW-104 is a new well cluster located between
CW-6 and CW-7.
Parameters!
Quarterly: VOCs
Indicators
Chloride
pH
Temperature
Specific Conduct.
Metals
Arsenic
Iron
Lead
Manganese
Cadmium
Annually: Barium, chromium, fluoride, mercury, nitrate,
selenium and silver (from the 1983 Court
Order)
3. Comment;
RIDEM requests a more detailed cost analysis breakdown of
the associated operation and maintenance costs that are
anticipated.
EPA Response:
A detailed cost breakdown for each alternative is found in
Appendix BB in the RI/FS Report. Its important to note .
that the cost analysis in the FS is primarily conducted to
provide EPA with an estimated comparative cost for each
alternative. These estimates are made with a number of
assumptions and the actual costs may vary between -30 and
+50 percent. The detailed cost information is developed
during the design phase.
Its also important to note that as discussed in response to
comment #2, the groundwater monitoring plan established in
the ROD is different than the one outlined in the FS. EPA
estimates the costs for this plan will be as follows:
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RESPONSIVENESS SUMMARY
page 14
VOCs $225/smpl x 15 smpl/qtr x 4 qtr/yr
Metals $80/smpl x 15 x 4
Indicators $40/smpl x 15 x 4
C.O. Metals $160/smpl x 15 x 1
Total Analytical Costs:
2 people x 3 days x 8 hrs x $20/hr x 4 qtr/yr
Total Sampling Costs:
Comment:
$13,500/yr
- $4,800/yr
- $2,400/yr
- $2,400/yr
- $23,100/yr
» S3.84Q/vr
- $26,940/yr
RIDEM has questions about the results of the air monitoring
at the landfill and the risk assessment developed based on
this data. RIDEM believes that more accurate analytical
results are needed in order to develop an appropriate risk -
analysis.
EPA Response:
EPA believes that the results are appropriate and sufficient
for the purpose of selecting a remedy for the Site. The
difficulties encountered at the Site such as the high
moisture content and high pollutant concentrations of the
gas made the use of conventional sampling techniques such as
sorbent traps tenuous. The results were based on techniques
designed specifically for L&RR after standard sampling
methodology failed.
EPA1s conservative position is that although there may be
questions regarding the validity of the quantitative data,
qualitatively, the risk assessment justifies the necessity
for gas treatment.
Comment:
RIDEM stated that the Department and the owners of L&RR
entered into a Consent Agreement in July 1983 (the 1983
Court Order) which addressed closure measures for the
landfill. Many of the components of EPA's Proposed Plan are
similar to the requirements outlined in the existing Consent
Order and Agreement. The restoration of wetlands and the
addition of a synthetic cover on the northeast portion of
the landfill have not been included as part of the closure
plans submitted to date. The Department agrees that
compliance with all applicable wetlands requirements must be
addressed, in addition to all of the other closure measures
required under the 1983 Court Order. The Department also
agrees that installing the additional cover, on the northeast
side slopes would further reduce infiltration of liquids
into the landfill; however, given the concerns identified in
the Department's first comment (A-l, above), the Department
requests that EPA provide further justification for the
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RESPONSIVENESS SUMMARY page 15
Landfill & Resource Recovery site
proposed cap.
EPA's Response;
There are a number of reasons why EPA is proposing to
upgrade the present landfill closure and, more specifically,
install a synthetic cover and stabilize the slopes on the
northeast portion of the Site. EPA's primary reasons for
installing the synthetic cover is to protect public health
and the environment and attain ARARs. The installation of
the synthetic cover will protect the groundwater and insure
compliance with the provisions of the RCRA Subtitle C
regualtions (40 CFR 264).
EPA considered the following facts when selecting the remedy
for the Site. First, the landfill is situated over the
Slatersville Aquifer which is designated as a potential .
future drinking water source. Second, EPA has no definitive
.information regarding the location, amount and types of
hazardous wastes within the landfill. ' Third, EPA also has
no information regarding the hydrologic flow patterns within
the landfill. There is a potential that the flow could be
channelized to areas containing the hazardous wastes.
Fourth, although presently there is no indication of an
organic contaminant plume migrating from the Site, there is
a potential that one could emerge in the future due to
transport mechanisms, such as gravity, that occur regardless
of the amount of infiltration. In light of the fact that we
know hazardous wastes were disposed of in the Site, there
are three possible explanations for the groundwater
monitoring results seen to date. First, the hazardous
contaminants have not yet entered the groundwater. Second,
the groundwater containing the hazardous contaminants has
not yet reached the boundary of the Site. Third, the
existing landfill conditions, such as the natural hydrologic
and geologic conditions within the landfill, the quantity of
wastes disposed and the existing cover, could be preventing
the generation or detection of a groundwater plume at this
time. If the first two explanations are correct, we can
expect to see an organic contaminant plume in the future.
In light of all of these knowns and unknowns, EPA believes
that it is necessary to protect the groundwater and to
minimize infiltration to be protective of public health and
the environment.
The statutory requirements established in CERCLA mandate
that EPA select a remedy that meets ARARs. In order to
comply with the RCRA Subtitle C regulations (40 CFR 264),
the landfill cover must minimize infiltration as discussed
in response to comment 1. A synthetic cover over the entire
landfills/ill minimize infiltration.
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RESPONSIVENESS SUMMARY page 16
Landfill & Resource Recoverv Site
B. ALTERNATIVE PREFERENCE
1* Commentt
RIDEM recommends that EPA consider the implementation of the
closure measures outlined in the 1983 Court Order, in
addition to wetland restoration, as an effective and
appropriate remedy for the L&RR Site.
EPA Response;
The existing closure conducted to date under the 1983 Court
Order between RIDEM and L&RR, Inc., was evaluated during the
RI/FS. The existing closure conducted to date does not meet
the requirements of CERCLA. More specifically, the existing
cover does not protect the groundwater. In addition, the
existing surface water drainage system and vegetation
establishment does not minimize erosion. Erosion from the
landfill has severely impacted and continues to deposit soil
in the wetlands. Before the wetlands are remediated, the
landfill erosion must be minimized; otherwise, continuous
wetland remediation will be needed. The 1983 Court Order
requires a methane recovery system. This system has yet to
be designed or constructed. This system must be designed
and constructed in accordance with EPA's Record of Decision
(ROD) to meet the requirements of CERCLA. EPA reviewed the
existing groundwater monitoring plan. In light of the
hydrologic and geologic data collected to date and the fact
that there is a potential for a groundwater plume to emerge
in the future, a more aggressive groundwater monitoring plan
is needed to meet the requirements of CERCLA. Finally, the
post-closure monitoring plan must take into consideration
EPA's selected remedy and the requirements in EPA's ROD to
meet the requirements of CERCLA.
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Landfill & Resource Recovery Site
PART 3. POTENTI&T.T.Y PRSPQNSIBT.F PAPTIES COMMENTS
A. TECHNICAL CONCERNS
Wehran Engineers, Inc. submitted extensive comments on
behalf of the owner of L&RR, Inc. These comments and EPA
responses to these comments are summarized, by subject area,
below.
1. Landfill Gas Emissions and Risk Assessment
a. Comment;
Wehran questions the validity of utilizing so-called
"future conditions" (uncovered vents) as the basis for the
air exposure and risk assessment. Wehran theorizes that -
the landfill gases would never be uncontrollably released
into the environment because the 1983 Court Order requires a
methane recovery system. Therefore, the "future conditions"
do not represent any anticipated actual future conditions.
The air risk assessment should be based upon current
conditions using fugitive emissions data for landfill gases
which may.be emanating from the Site.
EPA Response;
The risk assessment was based upon emissions from 5 sampled
air vents, of the 18 total vents found at the landfill. The
best approach to estimate fugitive emissions was thought to
be use of actual emissions from some portion of the total
vents, rather than introducing additional uncertainties by
modeling estimated fugitive emissions. The five vents
sampled, which are less than 1/3 of total vents, was
considered to present an acceptable estimate of future
fugitive emissions due to fissures in the uncovered portion
of the landfill.
Although the 1983 Court Order requires a methane recovery
and removal system, one has yet to be constructed at the
Site. As concluded in the RI/FS, a large volume of gas .
(775 cubic feet per minute (CFM)) is being generated within
the landfill. To protect .the integrity of the synthetic
cover, the gases generated in the landfill must eventually
be released. While it may be true that the vent gases may
never be uncontrollably released into the environment, the
landfill gases needed to be characterized not only for the
purposes of risk assessment but also for design, and
construction. Ultimately, when the treatment system is
designed and constructed, it must protect human health and
the environment. Information regarding the degree of hazard
associated with the untreated gas is necessary to design a
system that is protective. The RI/FS Report and EPA's
Proposed Plan clearly states that the vents are currently
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RESPONSIVENESS SUMMARY pag* 18
closed. With the information obtained during the RI/FS, EPA
has concluded that these vents should remain closed until a
treatment system is constructed.
b. Comment T
The vent velocity measurement technique does hot utilize
standard methodology or account for any variation across the
diameter of the pipe. The vane anemometer method does not
provide an accurate flow measurement as per EPA Method 2 and
could contain large errors. A more accurate velocity
measurement could have been obtained by attaching a larger
diameter duct to the vent pipe with access ports to permit
traverses and the utilization of a pilot tube and micro
manometer system. In addition, the vane anemometer utilized
is easily affected by ambient wind conditions and may
include a bias. No ambient wind data during sampling is .
provided in the report. Ultimately, this error results in a
reduced risk characterization.
EPA Response;
The vane anemometer employed a shield around the blades to
minimize ambient wind influences. The data .gathered with
the anemometer were used to assess the character of the vent
emissions and were not intended to provide a detailed
analysis of such emissions. The alternative method
recommended by Wehran (EPA Method 2) would have proven
highly inaccurate without hydrogen, oxygen and moisture
preanalyses of each vent to determine gas density.
c. Comment;
On page 7-12 of the RI/FS Report, reference is made to the
six inch pipe diameter stamped on the sides of the vent •
pipe. Is this ID or OD, and why wasn't an accurate measure
taken to confirm the pipe size?
EPA Response;
The pipe size was 6 inches, inner diameter. The stamping
was discovered after the initial measurement and only
served to confirm the measurement.
d. Comment;
The calculated percent changes in temperature between
uncapped and vented scenarios presented in Table 7-3 of the
RI/FS Report are incorrect; for example, the reported Vent 2
result is +46.3*. Referring back to Table 7-2, the
following calculation results in (1.8 - 7.5)/ 7.5 - -76%.
Many of the other reported values are incorrect as well.
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RESPONSIVENESS SUMMARY page 19
Landfill & Resource Recovery Site
EPA Response;
The calculated percent change in temperatures presented in
Table 7-3 were calculated using temperature in degrees
Celsius. For example, in vent 10, a +100% change in
temperature was noted for a corresponding temperature
increase of 68°F to 104°F. This percent change was
actually calculated using Celsius values of 20°C and 40°C.
e. Comment:
A footnote on Table 7-6 of the RI/FS Report indicates that
vent pipe velocity and temperature measurements were not
collected during the VOC sampling events. With the noted
variability of the vent flow rates, this is a significant
loss of data. No comparison of physical characteristics of
the vent emissions can be made between the sampling events
and the flow measurement events. With this missing data,
actual emission rates at the time of sampling could also
have been determined.
EPA Response;
The footnote referenced in the comment was incorrectly
written. The footnote should have indicated that velocity
data was not available for the 48 hour period of venting.
Section 7.4.5 of the RI/FS Report references this loss of
data. Exhaust parameter data was available for the
remaining VOC sampling events.
f. Comment;
Review of Table 7-7 in the RI/FS Report indicates that the
duplicate sample of vent 18 did not replicate the
identification of three compounds: 1,1,1 - trichloroethane,
trichloroethene, and bromoform. The discussion contained in
the RI/FS Report does not accurately represent that 3 of the
11 compounds were not replicated. Potential mis-
identification or field sampling error is indicated by these
results. Furthermore, if detection limit values are '
utilized for these non detected results, high relative
percent differences are indicated. This error results in
reduced risk characterization.
EPA Response:
It is noted that the duplicate samples from vent 18 did not
replicate the results for the three compounds noted and
field sampling error could have effected these results.
However, 1,1,1-trichloroethane was detected in 18 of 21
samples, trichloroethene was detected in 20 of 21 samples
and bromoform was detected in 13 of the 21 samples. All of
the compounds were detected at significant levels. Of the
three compounds, only trichloroethene contributed to the
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RESPONSIVENESS SUMMARY page 20
risk. Therefore, this fact is not expected to have
influenced the risk.
Commentt
On page 7-33 of the RI/FS Report, the worst case scenario
for the odor impact is based on the exit parameters from the
immediately uncapped scenario. However, no data exists to
determine a realistic estimate of the potential duration of
this scenario. Velocity or temperature data is presented
for the following periods of venting: 0, 12, 24, and 48
hours. On page 7-36, a statement is made that velocity did
not stabilize until the 12th hour of venting. Stabilization
could have occurred at some time period less than 12 hours.
If the vent flows had been more fully investigated, it would
have been possible to determine when flows stabilized and
subsequently to assess more realistically the duration of
this scenario.
EPA Response!
It is agreed that stabilization could have occurred before
12 hours of venting and the report should have indicated
this. Since it was not known when stabilization would
occur, the intervals of 0, 12, 24 and 48 hours were selected
to investigation a range of possibilities. To be
conservative and account for the uncertainties of computer
modeling and risk assessment, the worst case scenario was
based on the results from the immediate uncapped scenario.
It is also important to note that the vents are presently
closed due to down wind odor problems.
h. Comment:
As discussed on page 7-43 of the RI/FS Report, Wehran
questioned the potential, impact on the modeling results of
the terrain reductions in the receptor elevation input.
EPA Response:
Of the 53 terrain points reduced, 36 were associated with
the 100 meter on-site ring with maximum reductions of 13
feet. This ring was only of concern for on-site exposure.
The reductions made for off-site receptors numbered 17 and
occurred from 600 meters and beyond. The low plume exit
characteristics resulted in the worst-case impacts within
600 meters. Furthermore, the 17 off-site receptors with
reduced terrain were located east-southeast and south-
southwest of the Site, areas that were away from the maximum
impact locations. The terrain reductions had little impacts
on predicted concentrations.'
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RESPONSIVENESS SUMMARY page 21
Landfill & Resource Recovery Site
i. Comment t
The VOC averaging scheme discussed on page 7-43 of the RI/FS
Report introduces a significant increase in the average VOC
concentrations utilized for many of the seventeen compounds.
The results reported as non detected (ND) were discarded
from the averaging as if the only valid results are those
reported above detection limits. For those values reported
as ND, the method detection limit value could be utilized
for calculating the average. This bias impacts the air
dispersion modeling results as well as the risk
characterization results, through the over estimation of VOC
concentrations in vent pipe emissions.
EPA Response:
Owing to the inherent limitations of any scientific study,
any bias towards conservatism is desirable, especially in
regards to a public health assessment.
j. Comment t
The description of exposure -scenarios for inhalation of vent
pipe emissions are all based on the uncontrolled venting of
the five worst case vents. The qualification addressing
"should more vents be uncovered and have emissions similar
to these tested" presents a hypothetical situation not
likely to occur considering the Site conditions and history.
First of all, the Report describes the five worst case vents
as orders of magnitude greater (peak areas) than the
remaining vents on page 7-25. Therefore, similar emissions
are not likely from other vents. Second, there are no
current or future plans which incorporate uncontrolled
venting of the landfill gases. Although it is used as a .
worst case scenario for modeling and risk characterization,
the discussion of risk should include a statement that the
vents are not now or in the future proposed to be allowed to
vent to the atmosphere.
EPA Response:
The first point made by Wehran "similar emissions are not
likely from other vents" cannot be substantiated.
Currently, the emissions from 13 of the 18 vents are less
significant than the emissions from the 5 worst case vents.
This point does not mean that the emissions from the 13
vents may not pose a health hazard. The sample technique
utilized was specifically developed to assess high
concentrations. Other techniques could be utilized to detect
contaminants in the other 13 vents. Furthermore, while the
13 vents have lower emissions at the present time, there is
nothing to indicate that the landfill will continue to emit
at its present rate.
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RESPONSIVENESS SUMMARY page 22
AS stated in response to comment i.a. in this section, the
RI/FS Report and EPA's Proposed Plan clearly indicates that
the vents are presently closed. Given the potential risk
to public health from the vent emissions, EPA will insist
that they remain closed until a gas treatment system is
constructed that meets the objectives of EPA's Record of
Decision (ROD).
k. Comment t
The calculation of adult cancer risk is based on exposure
over a 70 year lifetime. The landfill gas generation rates
and concentrations will not only vary greatly, but the
generation lifetime for the landfill is much less that the
70 year exposure period. At a minimum, the flows will be
greatly reduced over time. The risk calculation does not
account for the major reduction in landfill gas emissions,
which will naturally occur over the lifetime of the
landfill.
EPA Response:
While it is agreed that gas emissions will decrease over the
life span of a landfill; there is no information to
indicate with any degree of certainty what reductions will
occur over what time period. Therefore, emissions were
assumed to continue over a full human lifetime. It should
be noted however, that for the most probable case, it was
assumed that exposure would only occur 75% of the time.
1. Comment;
The risk assessment states that there are no residences at
the off-site point of maximum impact. If not, why was this
location used in the risk assessment? Is this an expected
future condition? If so, this should be stated in the risk
assessment.
EPA Response:
Risks were calculated assuming exposure at the off-site
point of maximum impact to present a worst case scenario.
In addition, risks were calculated assuming exposure at 3
residential locations to present a most probable case.
m. Comment;
The predicted concentrations at the on-site maximum impact
point remain constant for at least the period of exposure (9
years). There is no basis for this assumption provided in
the RI/FS Report. It is probable that if the landfill
vents were opened, emissions could decrease with time.
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RESPONSIVENESS SUMMARY page 23
Landfill & Resource Recovery Site
EPA Response;
As stated previously, there are no quantitative data on the
decrease in gas generation rates or concentrations over the
life span of a landfill. Therefore, it was assumed that
fugitive emissions would remain constant. It should be
noted that the concentrations at the on-site maximum impact
point is an annual average value and that although higher
concentrations would occur due to metrological conditions,
the annual average is the most realistic value.
n. Comment;
The realistic worst case analysis is based on the assumption
that children will visit the on-site maximum impact point
twice a month for nine years and remain at that location
for four hours each time. There is no evidence to support
any of these assumptions. Furthermore, if a fence with
barbed wire is installed around the Site, there is no
probability of this circumstance happening at any time in
the future.
EPA Response;
There is physical evidence that the Site has been accessed
by individuals. This includes dirt bike tracks and trash.
The ventilation rate is consistent with a moderate activity
level, which is considered appropriate for children at play.
These assumptions apply to the Site as it exists now, which
are considered baseline conditions that would not require
long-term management and oversight, including site security
such as a fence.
o. Comment;
Source terms for air quality modeling are suspect and yet
greatly impact the health risk assessment. Specifically,
selection of source emission properties based on
measurements taken before the source has reached equilibrium
may not provide an accurate estimate. Second, failure of
the velometer prevents proposing the assumption that the
emissions have stabilized. Finally, vent velocities may not
be accurately assessed without barometric pressures
measurements.
EPA Response;
Vent gas exit velocities averaged 2.5 miles per, hour after
12 hours of venting and continued at this rate at 24 hour
point. The value represented a drop from the immediately
uncapped value of 5.1 mph. Since the drop continued after
12 hours, flow equilibrium was reached within the period of
sampling.
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RESPONSIVENESS SUMMARY page 24
l I Resource Recoverv Site
Although it has been suggested that atmospheric (barometric)
pressure affects landfill gas emissions, it is not expected
to be significant in this case. For a landfill the size of
L&RR, the primary source of emissions is the methane .
generated, which is a function of material decay and
decomposition. Atmospheric pressure will not direct the
rate of decay nor will atmospheric pressure significantly
alter an emission volume of 775 cubic feet per minute.
It is doubtful that the source terms will remain constant
for 70 years, nor was it ever stated in the RI/FS Report.
The uncertainty associated with this change is the reason
why worst case assumptions were used in completing the risk
assessment.
Comment t
There is no validation of the quantitative emissions
concentrations derived from field GC studies. A large part
of the risk assessment from the air exposure is due to two
compounds: 1,2, dichloroethane and carbon tetrachloride.
6C/MS samples failed to confirm the presence of these
compounds.
EPA Response:
Observed differences between the field GC sampling results
and the laboratory analyzed tenax and charcoal tubes may be
due to a variety of factors. Quantification of the charcoal
and tenax tubes was hampered by breakthrough and probable
loss of certain hazardous substance list (HSL) compounds of
concern due to displacement from the tubes by high
concentrations of other HSL and/or non-HSL organics.
Initial CLP laboratory analyses confirmed the existence of
high organic loadings on certain tubes. In addition, during
sorbent tube sample collection, water vapor condensation was
a recurring problem. The presence of water can adversely
affect sorbent tube performance. The field gas analyzed
samples were collected in gas bulbs which were not subject
to breakthrough or desorption losses as are sorbent tubes.
Sample analyses using the field GC based all comparisons of
peaks to volatile standards containing the targeted
compounds, with a standard analyzed at the start of the day
and every eight hours until the analysis day was complete.
Retention times (RTS) were matched based upon the observed
drift of the RTS in the samples and by generating relative
retention times (RRTS) to a late eluting compound (toluene).
Therefore, the identifications are considered valid.
As discussed in the RI, the sorbent tube data confirm the
field GC results indicating the presence of a wide variety
of chlorinated and non-chlorinated organic compounds in the
vent emissions. Both the charcoal and tenax tube data for
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RESPONSIVENESS SUMMARY page 25
Landfill & Resource Recovery site
samples from several vent locations indicate the presence of
many HSL organics in both the front and back tube portions
indicating the occurrence of breakthrough.
With respect to field GC data, it should be noted that
carbon tetrachloride was detected in four different samples
from each of five different vent locations and 1,2-
dichloroethane was detected in multiple samples from two
different vent locations.
From the health perspective, the realistic worst case
estimate .of health risks (1.1 x 10~3) to children due to
the inhalation of air contamination from vents exceeded the
EPA target range for risk of 1 x 10~4 by approximately an
order of magnitude. This total risk was due to significant
contributions from several air contaminants including
chloroform and tetrachloroethene/ 1,1,2,2-tetrachloroethane,
in addition to 1,2-dichlroethane and carbon tetrachloride.
The calculated risk due to any one of the constituents
considered individually approached or exceeded the EPA
target level of 1 x 10~4.
In addition, for this scenario the total calculated risks
from several other structurally similar chlorinated organics
(methylene chloride, 1,1-dichloroethene, and
trichloroethene) and benzene , all of which were detected,
were within a factor of three of the 10~4 upper bound target
risk.
In summary, the air sampling results indicate the presence
of a wide variety of organic constituents in the vent
emissions.
Comment;
The screening of gas treatment technologies in the FS was
not conducted correctly. To determine the reduction in
health risks achieved by each gas treatment technology, the
ambient concentrations produced by the five vent sources was
reduced by the destruction and removal efficiencies of each
technology. After treatment, there will be one source, the
stack. Ambient concentrations from one source will be
significantly less.
EPA Response;
It was acknowledged in the RI/FS Report that the selected
technology will change source emission parameters.
However, the intent of the investigation was to-characterize
the source contaminant term and the exhaust, parameters.
Although the exhaust parameters will change, the overall
contaminant feed rate and quantity will not differ because
of the selected technology. Knowledge of these terms will
allow a proper control technique, to be sized and
implemented.
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RESPONSIVENESS SUMMARY page 26
Landfill £ Resource Recoverv Site
r. Comment;
Some design efficiencies and cost estimates have not been
adequately assessed, particularly in regards to the gas
treatment technologies.
EPA Response;
The cost analysis in the FS is primarily conducted to
provide EPA with an estimated comparative cost for each
alternative. These estimates are made with a number of
assumptions and the actual costs may vary between -30 and
+50 percent. The detailed cost information is developed
during the design phase.
2. Landfill Performance Model
a. Comment t
The amount of leachate generated from the uncapped area of
the Site was determined by use of the HELP model. The
results of this hydrologic modeling are presented in Table
9-1 and 9-2 of the RI/FS Report. Based on a leachate
generation rate of 59% of the total incident precipitation
in uncapped areas, as compared with 0.7% for capped areas,
capping of this area was determined by the RI/FS as'
beneficial. However, upon inspection of Tables 9-1 and 9-2,
it is apparent that the modeling results are significantly
in error. Wehran Engineering has calculated the water
balance for the L&RR landfill using a method developed by
C.W. Thomthwaite, as applied to solid waste disposal sites
by D.G. Fenn, et.al. The results of the water balance for
the uncapped landfill areas show a percolation rate of 6.8
inches per year. This rate is 15% of the average annual
46.2 inches of incident precipitation, rather than the 59%
as calculated by the HELP model. Therefore, the RI/FS
assumption is approximately 400% off.
EPA Response:
Both of the methods utilized, the HELP model and the
Thomthwaite method as modified by Fenn, use analytical
methods to evaluate infiltration. However, both are
controlled by assumptions and input parameters and both
result in approximations. Wehran did not submit their input
assumptions with their comment or at the request of EPA.
Therefore, EPA could not evaluate the validity of Wehran's
results. In response to this comment, EC Jordan utilized
the Thomthwaite water balance method as modified by Fenn
with a set of input assumptions which were similar to the
ones utilized for the HELP model and acceptable to EPA.
This approach resulted in an infiltration of 16 inches/yr
(See Memo in Administrative Record from EBASCO dated
September 26, 1988).
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RESPONSIVENESS SUMMARY page 27
Landfill & Resource Recovery Site
In 1983, Wehran performed a water balance for the uncovered
area of the landfill using the method of Thornthwaite as
modified by Fenn and calculated an infiltration of 19.3
in/yr. Using this same method in their comments on EPA's
RI/FS, Wehran calculated 6.8 in/yr. These results
demonstrate the variation that can occurr in approximating
infiltration with different input parameters and
assumptions.
Using the HELP Model in the RI/FS, EC Jordan calculated
infiltration as 27.64 in/yr. The HELP model represents the
most conservative approach to calculating infiltration,
particularly on the uncovered area.
Based on a review of EC Jordan's assumptions and results,
EPA finds that the infiltration could realistically be in
the range between 6.8 in/yr and 19.3 in/yr or rather 185,000
gallons/acre/yr and 524,000 gallons/acre/yr, respectively.
The maximum infiltration calculated for the rest of the
landfill, which has a synthetic cover as part of the cover
system, was estimated to be 7,690 gal/acre/yr. Given the
uncertainties associated with landfilling of wastes and the
lack of information regarding the location of the wastes,
the type and amount of wastes disposed and the hydrologic
flow in the landfill, EPA finds this range of infiltration
in the uncovered area unacceptable. To meet the objectives
of CERCLA, to protect human health and the environment and
meet ARARs, a synthetic cover is needed in this uncovered
area.
b. Comment;
The specific version of the HELP model used was not
documented. However, in all versions Wehran has reviewed,
the model is not meant for landfill slopes greater than 10%
In the RI/FS Report, the model was used on slopes of 33% and
50%. One effect of using these slope factors in the model
is an inability to accurately predict average runoff
conditions. It is widely recognized in hydrologic
calculations that when the slope of the land is steepened,
the fraction of rainfall which becomes runoff increases. In
Table 9-2, for existing conditions, the percentage of runoff
at a 3% slope was calculated by the model at 21.37% of the
total annual precipitation. At a 33% slope, rather than the
runoff fraction increasing, the fraction decreased to 0.62%
of the total annual precipitation. The soil structure data
was identical for both slopes, as shown in Table 9-1. When
no cap barrier was included in the model design at 50%
slopes, the rainfall fraction, which was previously removed
from the model system by the barrier drainage layer at 33%,
was now.percolated vertically into the landfill. In fact, a
substantial amount, of this percolation (and the barrier
layer drainage at 33%) should have been calculated as
runoff.
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RESPONSIVENESS SUMMARY page 28
EPA Response;
EPA agrees that the HELP model is limited in its ability to
accurately represent slopes greater than 10% and it was
utilized as a conservative approach to the Site. The*
Thornthwaite method as modified by Fenn is probably a more
appropriate method for representing the infiltration at the
L&RR Site. However, the Thornthwaite method as modified by
Fenn is also strongly influenced by the assumed runoff
coefficient. Therefore, the estimates can be very
subjective since the user projects their "best" estimate as
to what the percent precipitation is actually running off.
EPA finds that the infiltration in the uncovered area could
realistically be in the range between 6.8 and 19.3 in/yr.
Given the uncertainties associated with the Site as
discussed above, EPA finds this range of infiltration
unacceptable. EPA believes that in order to meet the
objectives of CERCLA, to protect human health and the
environment and meet ARARs, a synthetic cover is needed in
this uncovered area.
3. Applicable or Relevant and Appropriate Requirements (ARARs)
a. Comment;
Given the fact that the HELP model results contained an
error regarding infiltration calculations and that runoff
rates in the non-capped area were not adequately considered,
the conclusion that the final cover does not achieve
applicable or relevant and appropriate requirements (ARARs)
is not adequately justified within the RI/FS Report.
EPA Response;
As discussed in previous responses, EPA believes that the
infiltration in the uncovered area most probably falls
between the range of 6.8 in/yr to 19.3 in/yr. However,
without site-specific tests, the infiltration could not be
exactly determined. In light of the uncertainties
associated with landfilling wastes and the lack of
information regarding the location of the hazardous wastes,
the types and quantities of wastes, and the hydrologic flow
in the landfill, EPA finds this range of infiltration
unacceptable for meeting the ARARs and in particular the
requirements of RCRA Subtitle C regulations which require
the landfill cover to minimize infiltration and migration of
liquids through the landfill.
b. Comment;
On page 2-7, the FS Report states that "although not
directly applicable" and "generally RCRA regulations have
jurisdiction at hazardous waste facilities that accepted
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RESPONSIVENESS SUMMARY page 29
Landfill 6 Resource Recovery Site __^_
RCRA-listed wastes after November 19, 1980; L&RR ceased
accepting hazardous waste in September 1979". However, EPA
proceeded to evaluate these RCRA regulations as if they were
relevant and appropriate requirements and then recommended
implementation of remedial alternatives on the basis of
these regulations that are "not directly applicable". The
basis for landfill ARARs at this Site should be the 1983
Court Order executed between L&RR and RIDEM.
EPA Response:
Section 121 of CERCLA requires EPA's selected remedy to
attain applicable or relevant and appropriate requirements.
For the L&RR Site, RCRA Subtitle C is not applicable
because the Site accepted hazardous waste prior to November
19, 1980. However, the RCRA Subtitle C regulations are
relevant and appropriate because the Site contains wastes
that are similar or identical to RCRA hazardous wastes and
hazardous constituents and the CERCLA action involves long-
term landfilling disposal. Furthermore, these regulations
address problems or situations sufficiently similar to those
encountered at the L&RR Site and their use is well suited to
the Site. Relevant and appropriate requirements must be
complied with to the same degree as if it were applicable.
Under the terms of Section 121, the 1983 Court Order is not
a requirement of general applicability which would govern a
CERCLA remedy.
c. Comment;
Wehran asked whether current air concentrations meet the
ARARs. Wehran stated that the Air Toxic regulations are not
clearly presented. Wehran asked whether these are emission
standards as referred to in Table 11-9 or ambient levels as
referred to on page 11-17. In either case, why aren't they
provided in Table 11-16, and how do the current landfill
conditions compare to them?- There is some indication of a
standard/guideline on Table 11-2, but it appears this refers
to the Risk Reference Dose (RfD).
EPA Response;
The Rhode Island Air Pollution Control Regulation No. 22,
"Air Toxics" present acceptable ambient levels. However,
minimum quantities of emissions, above which a generator
must report, are also stated. The Air Toxics regulations
are presented and discussed in Appendix Y of the RI/FS
Report. In addition, a discussion is presented in a
Technical Memorandum from EC Jordan dated July 15, 1988 and
included in the Administrative Record. The; existing
landfill vent emissions do not presently meet these
regulations. Since fugitive emissions were not
quantitatively characterized, it could not be determined if
the fugitive emissions meet these regulations.
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RESPONSIVENESS SUMMARY p«g« 30
4. EPA1s Proposed Plan
a. Commenti
Steep side slopes, up to 50%, can be readily stabilized with
proper drainage controls and suitable vegetative cover. •
Should a particular area show to be more susceptible to
erosion, the topsoil can be strengthened with a synthetic
mesh material. The key to proper vegetation establishment
is prompt re-dressing of any areas showing signs of erosion
and continual maintenance until a sturdy rootmat has been
established. Wehran feels that such an approach would
alleviate the need for any flattening of the existing slope.
EPA Response:
Based on observations made during the RI, the existing
vegetative cover is considered to be in "poor" condition on
the steep side slope areas. The existing root mat is thin
and plant density is low. Sandy, well-drained soils such as
those of the existing topsoil typically have difficulty in
establishing the good to excellent vegetative cover
necessary to stabilize those types of soils on steep grades.
Excessive soil loss, which has historically been a problem
at the Site, dan be temporarily lessened with synthetic mesh
materials, however, long-term minimization of soil erosion
without continued maintenance depends on vegetative
establishment which the existing soil on the steep side
slopes has not supported.
Flattening the steep slopes would reduce the potential for
excessive soil erosion and provide an opportunity for the
establishment of a higher quality vegetative cover.
b. Comment:
The conclusions of the RI/FS indicate that "an organic
plume is not migrating from the Site" and that "the L&RR
Site is not presently impacting the local private wells".
This, along with the incorrect results from the HELP model,
do not justify the need for capping the existing uncapped
side slopes on the northeastern side of the landfill.
Wehran believe that these areas should be revegetated after
the methane gas extraction system comes on-line. In the
interim, the side slopes should be reseeded where needed to
prevent erosion.
EPA Response;
As discussed in detail in*response to comment A.5. in Part
2, there are a number of reasons for upgrading the present
landfill closure and more specifically installing a
synthetic cover on the northeast portion of the landfill.
Although the groundwater monitoring results indicate that a
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RESPONSIVENESS SUMMARY page 31
Landfill & Resource Recovery Site
plume of hazardous contaminants is not presently migrating
from the Site, historical information indicates that a plume
could emerge in the future. Furthermore, EPA must select a
remedy that protects groundwater. The infiltration in the
uncovered area has been estimated to be 27.64 inches per
year, as calculated in the RI/FS Report using the HELP
model, 19.3 inches/yr, as calculated by Wehran in their 1983
closure plans using the Thornthwaite method as modified by
Fenn, 16 inches/yr, as calcualted by EC Jordan using the
same method, and 6.8 inches/yr, as calculated once again
using this method by Wehran in their 1988 comments. EPA
believes that the actual infiltration realistically falls
within the range between 6.8 in/yr and 19.3 in/yr. The
covered portion of the landfill reduces infiltration to
approximately 0.3 inches/yr. It is clear that a synthetic
cap on the uncovered portion of the landfill will minimize
infiltration and the migration of liquids through the
landfill to the lowest practical extent and protect
groundwater.
c. Comment t
The first component of EPA's Proposed Plan is upgrading the
existing landfill closure to conform with either Alternative
3 or Alternative 4 of the RI/FS Report. Wehran's position
is that the final cover plan proposed in the Court Order and
Consent Order and Agreement, dated July 13, 1983 (the 1983
Court Order), is appropriate and adequate for the L&RR Site.
EPA Response;
The closure plans established by Wehran for the 1983 Court
Order are not appropriate or adequate because they do not
meet the requirements of CERCLA. In order to meet the
requirements of CERCLA, the landfill closure must protect
human health and the environment.
It is evident from observing the impacts to the wetlands
that the existing closure is not protecting the environment.
The existing surface water runoff management system, slopes
and vegetation are not minimizing erosion and the eroded
soil is filling in the wetlands. The selected remedy will
upgrade the existing surface water management system,
stabilize the slopes and establish vegetation to minimize
erosion. Furthermore, the impacted wetlands will be
remediated and re-vegetated.
By not minimizing infiltration, the existing closure is not
protecting the groundwater. Considering the lack of
definitive information regarding the location, types and
amounts of hazardous wastes and the hydrologic flow within
the landfill, the synthetic cover in the northeast area is
necessary to protect the groundwater aquifer which is
designated as a potential future drinking water source.
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RESPONSIVENESS SUMMARY page 32
d. Comment t
The second component of EPA's Proposed Plan is installing a
gas collection and thermal destruction system. The gas
management program established by the 1983 Court Order will
provide the required benefits of controlling landfill gas
emissions.
EPA Response;
EPA has proposed three technical approaches that will reduce
gaseous emissions to levels that will eliminate the
estimated risk and be protective of public health. As
stated in the Proposed Plan, the effectiveness of the gas
treatment technologies proposed will have to be determined
by pilot testing programs of individual systems during the
design phase. The effectiveness of individual systems will
be judged by actual data generated during the pilot
programs. A methane recovery and removal system required by
the 1983 Court Order will have to demonstrate, prior to
construction, the capability to reduce emissions to levels
that are protective of public health and the environment.
e. Commentt
The third component of EPA's Proposed Plan requires regular
monitoring of the groundwater, surface water, and air.
Wehran Engineering supports a monitoring program as included
per the 1983 Court Order.
EPA Response;
The 1983 Court Order contains plans for monitoring the
groundwater and surface water. After consideration of the
comments made on the Proposed Plan, EPA established a
groundwater monitoring plan in the Record of Decision (ROD)
which is different than the ones discussed in the RI/FS
Report. In establishing the monitoring plan, EPA considered
the monitoring plan presented by Wehran as well as all of
the hydrologic and geologic data collected to date. The
groundwater monitoring plan established in the ROD is
necessary to meet the requirements of CERCLA. This plan
takes into consideration the fact that EPA is not selecting
a permanent remedy, the uncertainties associated with
landfilling of wastes and the fact that the landfill is
situated over the Slatersville Reservoir which is a future
potential drinking water source. It is also important to
note that the 1983 Court Order does not contain plans for
air monitoring. This monitoring is also needed-to meet the
requirements of CERCLA to insure that the gas treatment
system is protecting human health and the environment.
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RESPONSIVENESS SUMMARY page 33
Landfill & Resource Recovery Site
f. Comment:
In as much as the preferred alternative is aimed at reducing
the impacts of contaminants in the groundwater, General
Dynamics does not understand how the alternative can be
evaluated relative to reducing health impacts.
EPA Response;
As discussed in response to comment A.5. in Part 2,
although a plume of hazardous contaminants is presently not
migrating from the Site, there is a potential for one to
emerge in the future. The selected remedy is designed to
protect public health and the environment from the threat
posed by future releases. Presently, a potential risk to
public health and the environment is not posed from
ingesting the groundwater. However, the landfill is located
over the Slatersville Aquifer which is designated as future
drinking water source. The selected remedy is designed to
prevent a release to the groundwater while at the same time
monitoring to insure that any threat from a release will not
impact the intended use of the aquifer.
5. Wetlands
a. Comment;
The first paragraph on page 10-25 of the RI/FS Report states
that "the most severe environmental effects from the L&RR
Site are due to erosion of landfill soils and subsequent
sedimentation in the wetland floodplain". Wehran contends
that this conclusion is not a CERCLA issue.'
EPA Response;
Section 104(a)(1) of CERCLA states that "Whenever (A) any
hazardous substance is released or there is a substantial
threat of such a release into the environment, or (B) there
is a release or substantial threat of release into the
environment of any pollutant or contaminant which may
present an imminent and substantial danger to the public
health or welfare, the President is authorized to act,
consistent with the national contingency plan, to remove or
arrange for the removal of, and provide for remedial action
relating to such hazardous substance, pollutant or
contaminant at any time, or take any other response measure
necessary to protect the public health or welfare or the
environment."
There are substantial threats of releases qf hazardous
substances at the L&RR Site. The sand cover was installed
to prevent releases of hazardous substances. The correction
of the erosion from the sand cover at the Site, including
the restoration of the wetlands affected by that erosion, is
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RESPONSIVENESS SUMMARY page 34
a response action necessary to protect public health, or
welfare and the environment. Section 101 of CERCLA defines
"response" to include "removal", and defines the latter to
include "such other actions as may be necessary to prevent,
minimize or mitigate damage to public health, welfare'or the
environment which may result from the release or threat of a
release."
Section 101 states that the term "pollutant or contaminant"
includes "any element, substance, compound, or mixture,"
which, "after release into the environment and upon
exposure, ingestion, inhalation or assimilation into any
organism, will or may reasonable be anticipated to cause
death,." At the LtRR Site, the sand eroding from the
landfill cover is a substance that is causing death to
organisms in the wetlands. Furthermore, this sand is
preventing the reestablishment of the wetlands. The sand
needs to be remediated and future impacts need to be
prevented. CERCLA gives EPA the authority to remediate this
substance from the wetlands and prevent future impacts.
b. Comment t
The third paragraph on page 10-25 states "that continued
erosion is expected to prevent recolonization by wetland
plant species". Wehran notes that during the Site visit
conducted on August 5, 1988, recolonization by wetland plant
species was, in fact, observed in many locations impacted by
sedimentation.
EPA Response;
Recolonization of some sections of the wetland plant species
was observed on August 5, 1988, indicating sediment loading
rates were lower than expected in some areas. However, in
other areas, die off of alders which had been alive during
wetland investigation was observed, including that impacts
to the wetland are continuing to occur. Additionally, the
wetland continues to have a low value in terms of aquatic
habitat and other functional attributes.
c. Comment;
Extrapolation of effects from acute toxicity tests performed
in many different laboratories to field situations is an
inappropriate practice. The hypothesis that an impact on
the system exists based on chemical analysis of samples from
the wetland media is suspect. Furthermore, hardness data
was not collected to adequately assess the aquatic water
quality criteria.
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Landfill & Resource Recovery Site .
EPA Response:
Extrapolation of laboratory test data to predict impacts in
the field is a widely utilized EPA approved practice,.in
lieu of field test data. In addition, the toxicity data
reported were from tests reviewed by EPA according to
stringent protocol and deemed valid; they are listed in the
EPA Water Quality Criteria Document for each chemical.
Hardness of the water was not measured during the
environmental sampling; however, EC Jordan contacted RIDEM,
who said that 50 mg/1 is a typical hardness value for
surface waters in Rhode Island and should be used to
calculate protective criteria in the absence of site-
specific hardness data.
d. Comment; . -
The effectiveness of the remedial alternatives at reducing
the environmental impacts to the wetlands cannot be assessed
because no objective system of quantifying damage is
available. Remediation may cause more damage to the
wetlands.
EPA Response;
The sampling survey was qualitative in that no calculation
of diversity indexes or population densities were made.
However, it was clear from the species of invertebrates
identified and the numbers of individuals collected that
markedly lower population densities and fewer taxa existed
in areas containing large quantities of erosional sediment
compared with relatively unaffected areas. Although low
levels of toxicants were detected in the wetlands, the
deposition of erosional sediment has greatly reduced the'
value of the wetland in terms of aquatic habitat and other
functional attributes. Therefore, remediation is warranted
and will not result in significantly greater damage than has
already occurred.
The magnitude and degree of damage to the wetlands is
adequately described and the areas that require remediation
are clearly delineated in the RI/FS Report. Further details
will be gathered during the design phase of remediation and
erosion management will be completed prior to proceeding
with wetland remediation.
6. Remedial Alternatives Analyzed
a. Comment;
Wehran concurred with the results of the RI/FS Report that
gas evacuation with some type of combustion system is
worthwhile for the L&RR Site. However, gas evacuation
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RESPONSIVENESS SUMMARY page 36
systems have performed well in non-capped sites. Individual
gas wells can be adjusted for optimal vacuum pressures,
thus, assuring that air intrusion is not a significant
factor in the combustion process. Should a minor amount of
air penetrate through the cover soils and be collected
within the system, a possible soil and waste drying effect
would result and further reduce potential leachate
generation. Therefore, Wehran does not feel the argument
favoring a synthetic cover, based on the grounds of air
intrusion, has any merit and requests further consideration
of Alternative 2 and an active gas collection system.
EPA Response;
•
Although gas extraction systems can be operated on sites
without synthetic covers, to obtain the best operating
conditions the gas extraction system should be operated in
conjunction with a synthetic cover in the northeast area.
An uncovered landfill affords the opportunity for air to
enter the landfill and dilute the landfill gas. The concern
is not only that there would be dilution, but also that the
dilution would be uncontrolled. This situation would reduce
the quantity of combustible methane gas being drawn, reduce
the quality of the gas to be burned, and introduce a greater
variability into the landfill gas composition. In turn, the
efficiency production would be reduced.
Landfill gas is generally combined with 4 to 6.5 volumes of
air per volume of gas to obtain a proper burning mixture.
With the current cover system, an unknown quantity of air
would be drawn into the landfill. It would be difficult to
control the air to gas ratio required for proper operation
without supplemental fuel and continuous monitoring of
system performance.
Gas treatment is required due to the presence of hazardous
constituents in the landfill gas. Installation of the liner
would increase the probability of attaining the destruction
and removal efficiencies expected with the systems.
Additionally, the primary reason for installing the
synthetic cover in the northeast area of the Site was to
protect the groundwater. Alternative 2 does not include a
synthetic cover and therefore does not provide the necessary
groundwater protection.
b. Comment;
There were no investigations in the landfill. Since
geophysical surveys were not conducted within the limits of
the landfill, the contaminant source has not been adequately
characterized. Without this information, the effectiveness
of the alternatives at minimizing infiltration can not be
properly assessed.
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Landfill & Resource Recovery Site ___
EPA Response:
EPA's RI/FS for the L&RR Site was conducted using a phased
approach. At the conclusion of the first phase, EPA
discovered that a plume of hazardous contaminants was not
migrating from the Site. Therefore, EPA did not believe it
was necessary to conduct investigations within the landfill
and disrupt the existing landfill cover which may be
protecting the groundwater. Instead, EPA believes that it
is more effective to implement a groundwater monitoring
program to assess the performance of the Site.
7. Site History
a. Comment;
The information presented on page 1-9 and ES-2 of the RI/FS
Report is incorrect. In 1985, Wehran prepared a Remedial
Investigation Summary Report. This was not a separate
investigation but a summary report utilizing data from
numerous engineering investigations and reports for the
L&RR Site. The purpose of this report was to identify to
EPA that an adequate amount of investigative data was
available to initiate remedial activities in conformance
with the Court Order between L&RR and the RIDEM. 'Wehran was
never advised that this report was evaluated by EPA's
contractor (GCA Corporation) or that there were data gaps
or deficiencies noted during this evaluation, nor was Wehran
given any opportunity to correct any alleged deficiencies.
EPA Response:
EPA acknowledges Wehran's comment and adds the following
clarifying points. Between June of 1983 and January of
1985, EPA conducted numerous negotiations with L&RR, Inc..,
to conduct an RI/FS. An agreement was not reached and EPA
withdrew from the process of negotiations on January 29,
1985, intending to conduct an RI/FS using federal funds.
The owner proceeded to close the landfill in January of 1985
according to the 1983 Court Order and plans developed by
Wehran. During 1985 and 1986, GCA under contract to EPA,
observed the Site closure operations and evaluated its
compliance with RCRA Subtitle C regulations. The
information obtained by GCA was intended to supplement
information obtained during EPA's RI/FS. EPA notified
L&RR, Inc., of deficiencies in the closure operations in a
number of written correspondence throughout the closure
operations.
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RESPONSIVENESS SUMMARY page 38
8. Groundvater and Geophysical Investigations
a.
The number, location and design of the wells is insufficient
for characterizing current or future impacts of contaminants
on groundvater.
EPA Response;
A number of factors must be considered when establishing a
network of groundwater monitoring wells at a site.
Presently there are 14 groundwater monitoring wells
installed around the perimeter of the Site. Nine of these
wells were installed by the present Site owner. After
reviewing hydrologic and geologic information for the Site,
EPA installed five additional monitoring wells during the
RI/FS to gather information to characterize contamination at
the Site. The long-term groundwater monitoring plan
outlined in the Record of Decision requires a new cluster of
wells. This cluster will have two wells and will be located
between monitoring well clusters CW-6 and CW-7. The
specific location of this cluster will be decided during
the design phase. Given the geologic conditions at the
Site, this monitoring well network will identify a
contaminant groundwater plume migrating from the Site.
Given that above background concentrations of inorganic
substances and other parameters in the groundwater have been
.detected down gradient from the Site, this suggests that
'these wells are properly located to also intersect organic
contamination .
b. Comment
The geophysical investigation was extremely limited since
only six stations were vertically sounded. Furthermore, the
zones of high conductivity were interpreted to be due to
possible leachate. However, the high conductivity could be
due to the power lines, buried drums or other metal objects
within the landfill.
No explanation was given for the inability to interpret
vertical resistivity soundings B, E and F.
EPA Response;
The data from vertical electrical resistivity soundings was
very limited as noted and the data was not used in a
quantitative sense for the construction of geologic
profiles.
During the RI, the proximity of the power lines was not
expected to substantially affect the results. Data that was
expected to be the result of or affected by buried drums and
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RESPONSIVENESS SUMMARY page 39
Landfill & Resource Recovery Site
debris was indicated as such in the results.
No solutions are presented for vertical soundings B, E and F
because the data quality was not sufficient to provide
reliable solutions. There was "scatter" present in all
three of these data sets, perhaps due to lateral variation
in stratigraphy/moisture conditions.
c. Comment;
Bedrock interpretations in the RI were base on five test
borings and geophysical data. The spacial distribution is
not adequate for accurate bedrock elevation interpretation.
EPA Response:
It is correct that fewer hydrogeologic data were obtained
from the bedrock flow system. In an attempt to further our
understanding of the bedrock flow regime, a water balance
was conducted to determine the flow into or out of the
bedrock aquifer. Exploration of the bedrock would have been
conducted during a latter phase of study if significant
overburden contamination was encountered in the first phase.
d. Comment;
Fate and Transport of the groundwater is not adequately
characterized. It is likely that the ice contact deposits
form the primary pathway for migration of contaminants from
the landfill to off-site areas since the permeability of
this unit is estimated to be more than the kame delta
deposits.
EPA Response:
A specific figure for indicating groundwater flow in the ice
contact deposits was not developed for several reasons.
First, the ice contact deposits do not appear to be aerially
extensive and seemed to occur as a lense. Second, where
they were encountered, the potentiometric surface was very
similar to the overlying kame delta deposits.
9. Miscellaneous
a. Comment;
Tables 11-1 and 11-2 are not provided in the RI/FS Report
and, as such, Wehran is unable to provide comment. Wehran
requests that these tables be made available for review and
comment.
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RESPONSIVENESS SUMMARY page 40
& Resource Recoverv Site
EPA Response!
These tables were present in the original RI/FS document. A
copy of the original document was submitted to L&RR, Inc.
Wehran could have requested a copy of these tables from the
original document from either EPA or L&RR, Inc., during the.
comment period. Additionally, a complete copy of these
documents were available for public review in two
repositories as indicated in EPA's Proposed Plan.
b. Comment!
None of the data from the previous reports were used in the
RI/FS completed by EC Jordan.
EPA Response!
The L&RR Site has been the focus of several investigations.
The information and data developed in these prior studies
and investigations has been considered, and where
appropriate, has been used in the evaluations for the L&RR
RI/FS. Most of this data could only be used qualitatively
because quality assurance/quality control information was
not available for the data.
B. LEGAL CONCERNS REGARDING EPA INVESTIGATIONS AND THE PROPOSED
PLAN
1. Site History
a. Comment;
The company that conducted the RI/FS, namely E.C. Jordan
Company, used to be known as Perkins Jordan, Inc. The RI/FS
Report fails to mention that the consultant which was
advising the State of Rhode Island in matters regarding the
L&RR Site leading up to the Consent Order and Agreement was
none other than this identical firm, at the time called
Perkins Jordan. Consequently, the credibility of the
current recommendation by this firm to spend five to six
million dollars on the slopes is undermined by the fact that
in 1983 this same firm studied this Site and did not make
this recommendation.
EPA Response!
It is correct that in 1983, Jordan Co. personnel working as
part of Perkins Jordan, Inc., served as consultants to the
RIDEM. Jordan's role at this time was to provide expert
testimony on the potential for the L&RR landfill to impact
domestic wells in the area. Jordan personnel reviewed
available data provided by RIDEM and indicated that, in
their professional judgement, the potential for impact to
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RESPONSIVENESS SUMMARY page 41
Landfill & Resource Recovery Site
wells existed. However, during that study no samples were
collected or analyzed and no engineering evaluations were
made regarding landfill design closure.
b. Comment;
Nowhere in the RI/FS Report is there any mention that in
1983 the RIDEM and L&RR, Inc., entered into a Consent Order
and Agreement setting forth how to close the Site in an
"environmentally sound manner". Furthermore, at a. contested
hearing on July 13, 1983, the Superior Court of the State of
Rhode Island approved that Consent Order and Agreement,
entered it as a Court Order, and retained jurisdiction over
the Site. The 1983 Court Order approved and instituted
stringent plans for: final operation, closure, capping,
methane recovery and removal, post-closure monitoring,
setting aside money for long-term monitoring, stabilization
of slopes, vegetating slopes, and litter and dust control.
The plans for these were explicitly incorporated as part of
the Court Order.
EPA Response;
The purpose of this RI/FS Report was not to give a detailed
explanation of the history of the litigation between RIDEM
and L&RR, Inc. EPA is aware of the 1983 Court Order.
However, EPA was not a party to the State Court proceedings
and is not bound by its terms and conditions. The
Administrative Record contains extensive documentation
regarding the history of the Site as well as a copy of the
1983 Court Order. All of this information was reviewed by
EC Jordan prior to conducting the RI/FS.
c. Comment:
The RI/FS fails to mention that before the RIDEM agreed to
enter into the Agreement on June 29, 1983, the RIDEM sent
all these plans and proposals to the EPA for review. These
plans explicitly dealt with slopes and covers as well as the
extent of infiltration and steps to minimize it. After
intensive review by EPA and meetings between and among the
EPA, the RIDEM, and L&RR on June 20, 1983 and June 26, 1983,
the EPA gave the RIDEM its OK to enter into the Consent
Order and Agreement (the 1983 Court Order). In reliance on
that, on June 29, 1983, the RIDEM proceeded to sign the
Consent Order and Agreement.
Along those lines, the RI/FS Report also fails to mention
that the EPA reviewed the 1983 Court Order as a" remedial
action and as a RI/FS back in 1983. The EPA analyzed the
1983 Court Order from that point of view and made comments.
Those comments are set forth in an EPA letter dated July 26,
1983. Consequently, the credibility of this report's
recommendations is eroded by the fact that the report fails
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RESPONSIVENESS SUMMARY page 42
to mention that the EPA in 1983 reviewed the 1983 submission
both as a remedial action and as an RI/FS and did not find
fault with those parts which the current report finds fault
with.
EPA Response;
EPA did not approve the 1983 Court Order between L&RR, Inc.,
and RXDEM, either as a fulfillment of the requirements of
the National Contingency Plan (NCP), 40 CFR Part 300, or in
any other sense. EPA's July 26, 1983 letter to David Wilson
explicitly states that RIDEM had recommended the settlement
to EPA, as they were required to do by the terms of the
Court Order, but the letter does not say that EPA had
accepted the RIDEM's recommendation. In fact, EPA's letter
recommended substituting a different groundwater monitoring
plan and specifically queried whether remedial action had
been considered to prevent off-site groundwater
contamination. The record shows that after reviewing the
July 26, 1988 letter, L&RR, Inc., with its consultants,
Wehran Engineering, met with EPA and discussed additional
work to be covered by an administrative consent order to be
issued by EPA on consent to L&RR, Inc.
The record shows that in subsequent months, EPA attempted to
negotiate with L&RR, Inc., for the performance of a Remedial
Investigation/Feasibility Study which would satisfy federal
requirements. The record shows that EPA considered the
available information on the Site insufficient for EPA to
approve L&RR's closure plans. Specifically, EPA wanted
further investigation of the bedrock aquifer, the potential
for off-site groundwater contamination, the extent of off-
site contamination, if any, the extent of impacts on off-
site surface water and wetlands and the effect of the risk
posed by air releases.
In a letter dated December 13, 1984, David Wilson of L&RR,
Inc., informed EPA that L&RR, Inc., would not sign EPA's
proposed consent order. Mr. Wilson proposed to submit new
information to EPA in an effort to convince the Agency that
the order was unnecessary. EPA replied in a letter dated
January 29, 1985, stating that EPA was withdrawing from
negotiations with L&RR, Inc., and clearly stating that EPA
was reserving the right to take further actions, either on
its own or through its enforcement powers to obtain a
complete RI/FS. EPA indicated its willingness, on the basis
of a satisfactory RI/FS, to consider whether closure under
the Court Order would be sufficient to allow delisting of
the Site from the National Priorities Lists (NFL). In the
same letter, EPA detailed the history of its communications
with L&RR, Inc. EPA emphasized that it did not agree with
L&RR's position that EPA's July 26, 1983 letter constituted
an "approval" of the 1983 Court Order. EPA stated that it
had never found that the closure satisfied EPA's
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RESPONSIVENESS SUMMARY page 43
Landfill & Resource Recovery Site
requirements, and indicated that only compliance with the
landfill closure standards of RCRA would satisfy EPA's
policy (That policy has since been made statutory in SARA).
EPA wrote to L&RR, Inc., on May 13, 1985, re-iterating that
EPA was not a party to the Court Order. . The letter offered
comments, emphasizing that the comments were not offered as
conditions for EPA approval of L&RR's work, which EPA would
hot give outside of an enforceable consent order with EPA.
EPA's comments specified that the closure did not appear to
satisfy the requirements of 40 CFR Subparts F,G and N. EPA
specifically indicated that the proposed cover appeared
unlikely to provide long-term minimization of infiltration.
Subsequently, in letters dated June 7, August 13, and
October 10, 1985, EPA commented on certain aspects of L&RR
activities, while re-establishing that EPA was not prepared
to give L&RR formal approval of its closure. EPA noted
that it did not have the authority to enforce the state'
consent order, and did not have resources to carry out a
comprehensive review of activities carried out by a party
which had refused to enter an enforceable consent order with
EPA. EPA's comments were offered only as "comments and an
indication of the standards against which the Site closure
may be evaluated by EPA in the future." EPA again
reiterated its position and set forth in detail its
concerns about L&RR's closure in a letter dated November 1,
1985, identifying specifically the lack of a cap in the area
which EPA now proposes to cap. This letter was sent to L&RR
before completion of the closure. In summary, the record
clearly indicates EPA's disapproval with the closure
conducted by L&RR to date.
d. Comment;
The RI/FS forgets to mention that the Superior Court of the
State of Rhode Island has retained jurisdiction over the
Site. With due respect to the EPA, no one has any authority
to do anything to the L&RR Site except in conformity with
the terms and conditions of that Court Order. While federal
courts generally have jurisdiction in Superfund cases, it is
doubtful that a federal court would intrude on the existing
exercise of state court jurisdiction, given the doctrine of
comity, notions of estoppel, and the conclusion of the RI/FS
that neither groundwater nor the surface water nor the
sediments pose a threat to public health.
EPA Response;
The state proceedings have not deprived EPA of the authority
to carry out response actions or take enforcement under
CERCLA. In fact, CERCLA §122(e)(6) specifically prohibits
any responsible party from undertaking any remedial action
without authority from EPA after EPA has commenced an RI/FS.
Thus, L&RR may not carry out further remedial action without
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RESPONSIVENESS SUMMARY P*?e 44
federal approval.
e.
There are several inaccuracies regarding the history of the
Site in the RI/FS Report. This comment is intended to
correct some of them.
L&RR's landfill license was up for renewal as of December 1,
1980 and L&RR filed a timely renewal application. Since
L&RR had made a timely and sufficient application for the
renewal of its license, its existing license did not expire.
Its application was finally determined by the department at
the end of October 1981 and pursuant to 6.L. 42-35-14 (b),
the reviewing court in successive orders continued the
license in effect through mid-January 1985.
On November 9, 1981, L&RR ceased operating in response to a
RIDEM order. L&RR went to court to get a court order.
L&RR ceased operations from November 9, 1981 until December
28, 1981, at which time the Superior Court of the State of
Rhode Island ruled. The Court ruled that the RIDEM decision
dated October 30, 1981 was "replete with procedural and
substantive anomalies of grave proportions" and issued a
court order allowing L&RR to continue to operate. L&RR
resumed operation that afternoon.
The RIDEM tried to appeal the Superior Court order but was
not successful. At that juncture, the RIDEM issued a second
order against L&RR to cease operations. L&RR went to court
and asked to have the RIDEM held in contempt. On January
20, 1982, the Superior Court of the State of Rhode Island
held the RIDEM in contempt and issued an order that L&RR
could continue to operate under the supervision and
jurisdiction of the State of Rhode Island. The RIDEM on -or
about January 22, 1982 withdrew its second order. However,
L&RR remained under the supervision and jurisdiction of the
court which is in effect today. L&RR closed pursuant to a
Superior Court order issued on July 13, 1983 which allowed
L&RR to continue operating through mid-January 1985. As
January 1985 approached, there was a dispute as to whether
certain conditions set forth in the court order would allow
L&RR to stay open longer than the date originally planned
for, which was January 13, 1985. L&RR and the RIDEM brought
this to the attention of the court before that date. Court
hearings were held, at the close of which on January 20,
1985 the court ruled that the conditions justifying L&RR
staying open further had not been met and L&RR was ordered
to close in conformity with the previous court order, which
it did.
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RESPONSIVENESS SUMMARY page 45
Landfill & Resource Recovery Site
EPA Response;
EPA acknowledges this information and entered it into the
Administrative Record.
2. Applicable or Relevant and Appropriate Requirements (ARARs)
a. Comment;
The 1983 Court Order have extraordinarily strong bearing on
what are the applicable and relevant and appropriate
standards by which this Site should be judged. CERCLA
indicates that ARARs are supposed to be site-specific.
There is hardly anything more site-specifie than a Court
Order in a contested case determining what is
environmentally sound for this Site. Therefore, as a matter
of law, that Court Order sets forth the applicable and
relevant and appropriate standards.
EPA Response:
CERCLA §121 establishes the clean-up standards to be met
under CERCLA. A court order is not a "promulgated standard,
requirement, criteria or limitation" which must be met by a
CERCLA remedial action. Section 121(d)(c)(iii) specifically
requires that state ARARs be of "general applicability", and
be based on "hydrologic, geologic, or other relevant
considerations." Moreover, §121 does preclude imposition of
more stringent federal standards where state clean-up
standards are less stringent than relevant federal ones.
b. Comment t
The RI/FS Report discusses applicable Rhode Island
regulations governing covers for hazardous waste sites and
specifically a cover thickness requirement of 24 inches.
However, the 1983 Court Order contains a statement by the
Rhode Island Department of Environmental Management and its
Director that they accept and approve this Court Order and
Agreement, "as full compliance with and fulfillment of any
and all requirements of all applicable rules, regulations,
and statutory provisions under the jurisdiction of the RIDEM
and the Director". This statement negates the RI/FS
Report's claim that state ARARs require more.
EPA Response;
EPA finds the 24-inch cover requirement to be "relevant and
appropriate," even if it is not "applicable*1 because of
RIDEM's settlement with L&RR. See also preceding
responses.
c. Comment:
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RESPONSIVENESS SUMMARY page 46
l & Resource Recoverv Site
The RI/FS assumes that the RCRA standards are "relevant and
appropriate" to the entire Site. However, that fact is not
substantiated by the record. It is particularly not
substantiated with regard to the steeper slopes. The'RCRA
standards are applicable to hazardous waste sites. The
RI/FS states that hazardous waste was placed in one area of
the landfill and covered with a synthetic cover in 1979.
More trash was placed on top of this area and then another
synthetic cover was placed pursuant to the 1983 Court Order.
Therefore, the RCRA standards are not relevant and
appropriate.
EPA Response;
EPA finds that the RCRA requirements are relevant and
appropriate at this Site because they address problems or
situations that are sufficiently similar to those at other
hazardous waste sites. There is information that clearly
indicates that hazardous wastes was disposed of at the Site.
However, there is no definitive information regarding the
location of the hazardous waste. The Site owner states that
hazardous waste was co-disposed in the north-central area of
the Site and covered with a synthetic cover in 1979. Other
reports in the Administrative Record indicate that this nay
not be entirely correct. Information regarding the existing
condition of the cover installed in 1979 is not available.
Information regarding the hydrologic flow within the
landfill is also not available. Channelized flow could
result in infiltration from uncovered landfill areas
impacting areas containing hazardous waste. RCRA Subtitle C
regulations for closure of landfills are well suited to
address the situation at this Site and must be applied to
the entire landfill.
In addition, CERCLA is concerned with preventing a release
of "hazardous substances" and the closure standard in the
RCRA regulations is designed to prevent the release of
"hazardous constituents." The hazardous waste is not
necessarily the only source of hazardous substances or
hazardous constituents. EPA therefore believes that the
RCRA clousre performance standard should apply to the entire
landfill. EPA also believes that extension of the synthetic
cover would be required under other closure standards
applicable to solid waste landfills including RCRA Subtitle
D, the Rhode Island Solid Waste Management Act and Rhode
Islands's Groundwater Protection Act.
d. Comment;
\
The key date in the analysis of relevant and appropriate
requirements is July 13, 1983, the date the Superior Court
of the State of Rhode Island determined what would be the
appropriate way to close the Site in "an environmentally
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RESPONSIVENESS SUMMARY page 47
Landfill & Resource Recovery Site
sound manner." The RI/FS Report sets forth the .laws,
regulations, and guidances it relied on. Virtually all of
them were adopted after that date. There already was a
remedial action in effect on July 13, 1983, before any of
these things took effect. The issue of the appropriate
remedial action has already been determined in a contested
case by a court of competent jurisdiction in 1983.
Therefore, amendments to the federal law after the fact are
not relevant.
EPA Response:
Nothing in CERCLA §121 supports the contention that
standards adopted after the settlement of a state
enforcement action are not relevant and appropriate.
3. Landfill Gas Emissions and the Risk Assessment
a. Comment t
The report concludes that five million dollars must be spent
on the steep side slopes because of the risk to the public
from air emissions. However, the report never tested the
air emissions from the side slopes. Therefore, there is no
evidence in the record to substantiate that conclusion.
EPA Response;
The RI/FS report does not state that five million dollars
must be spent on the steep side slopes because of the risk
to the public from air emissions. The work on the steep
side slopes is primarily being conducted to protect the
groundwater and the wetlands. The synthetic cover proposed
will also enhance the treatment of the gases from the vents
which poses a potential risk to public health. Detailed'
information on the cost analysis is presented in Appendix BB
of the RI/FS Report. It is clearly stated that the cost for
the work on the steep side slopes is estimated to be between
$600,000 and $700,000.
4. Remedial Alternatives Analyzed
a. Comment t
The RI/FS Report's repeated reference to the no-action
alternative as meaning no remedial action is a material
misstatement of fact. There already is a court-approved
remedial action in place.
EPA Response:
In conducting an RI/FS according to the NCP, EPA must
evaluate what is referred to as the "no action" alternative.
The evaluation of the no action alternative provides EPA
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RESPONSIVENESS SUMMARY page 48
Recoverv Site
with information regarding the risks posed to human health
and the environment if no remedial actions are conducted at
the Site. In the case of L&RR, the Site owner had conducted
work at the Site prior to completing an RI/FS. The "no
action" alternative evaluated by EPA considered the work
conducted by the Site owner at the time of completion of the
RI/FS.
5. EPA's Proposed Plan
a.
Under CERCLA Section 121, even if RCRA standards were
relevant, no remedy can be approved unless it is "cost-
effective". This proposal patently is not. The RI/FS
Report states that, "On the basis of an assessment of
existing site hydrogeologic and chemical data, the
groundwater, surface water, and sediments do not pose a
threat to public health." Given the fact that there is
already a remedy in place and the remedy is working, it is
not obvious in any manner whatsoever how spending an
additional five million dollars could be cost-effective.
EPA Response;
As discussed in many responses previously, the selected
remedy and specifically the synthetic cover is intended to
protect the groundwater. Although groundwater impacts are
not evident to date, it is possible that a groundwater
contaminant plume may emerge in the future. EPA must chose
a remedy that is protective of human health and the
environment, meets ARARs, is cost effective and utilizes
permanent solutions to the maximum extent practicable.
Comment t
The RI/FS Report argues that one small part of the Site does
not minimize infiltration. However, from the point of view
of the entire Site, the Site as a whole minimizes
infiltration. If the landfill owner had not put a cover
over 80% of the Site pursuant to the 1983 Court Order and
Consent Order and Agreement, we would find ourselves in a
situation today where we would have to determine over what
part of the Site it would be cost-effective to put a liner.
The only logical conclusion that could be reached would be
that the only cost-effective area for placing a liner is the
identical area where the liner now exists. Consequently,
had no liner ever been put down, a report done today would
conclude that placing a liner over 80% of the Site would
effectively minimize infiltration.
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RESPONSIVENESS SUMMARY page 49
Landfill & Resource Recovery Site
EPA Response;
The RCRA Subtitle C regulations in 40 CFR § 264.310 are
relevant and appropriate at the L&RR Site. These
regulations, among other provisions, require an owner'or
operator at final closure to'cover the landfill with a final
cover designed and constructed to provide long-term
minimization of liquids through the closed landfill. L&RR
chose to close the landfill by capping approximately 80% of
the landfill surface area with a synthetic cover. This
leads one to conclude that L&RR felt that a synthetic cover
was a practical solution to reducing infiltration to the
landfill. EPA believes that to reduce the infiltration to
the smallest amount, requires a synthetic cover over the
remaining 20% of the landfill surface area. A synthetic
cover over the entire landfill will attain a standard of
performance equivalent to the RCRA Subtitle C closure
standard and assure protection of human health and the -
environment.
c. Comment;
With regard to a methane recovery system, we note that the
1983 Court Order requires a methane recovery system. There
is no reason for EPA to get involved in that because the
state already has that within its jurisdiction.
Furthermore, on February 11, 1987, L&RR, Inc., entered into
a contract with O'Brien Energy Systems, Inc., for the
installation of a methane recovery system at the Site. The
RI/FS establishes that once that system is in place, it will
remedy any air problem, if there is one.
EPA Response;
Section 122(e)(6) of CERCLA specifically prohibits any .
responsible party from undertaking any remedial action
without authority from EPA after EPA has commenced an RI/FS.
Thus, L&RR may not carry out further remedial action without
federal approval. Due to the potential risks posed by the
landfill's gaseous emissions, this system must be
implemented in accordance with EPA's Record of Decision and
meet EPA's approval.
The RI/FS Report does not establish that any particular
methane recovery and removal system will remedy air
pollution problems. The RI/FS evaluated technologies that
are capable of reducing the gaseous landfill emissions to
the levels necessary to protect public health. Since EPA
has not evaluated a specific design, it is .not clear that
the O'Brien Energy Systems, Inc., gas control system will
achieve the emissions reductions necessary to meet the
standard set by EPA's Record of Decision (ROD).
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RESPONSIVENESS SUMMARY page 50
IV. REMAINING CONCERNS
At the public informational meeting held in North Smithfield on
July 19, 1988, and at the informal public hearing held on August
10, 1988, local residents raised issues of concern for the'L&RR
Site regarding the design and implementation phase of EPA's
selected remedy. The principle issues are described below, along
with statements about how EPA intends to address these concerns.
1. Groundwater
Citizens continue to be very concerned that a contaminant
plume may form in the groundwater beneath the landfill and
fail to be detected by the existing monitoring wells. They
are concerned that their residential wells may become
contaminated as a result.
As a result of this concern, EPA once again reviewed the '
hydrologic and geologic information for the Site and
established a groundwater monitoring plan that would detect
a groundwater plume emerging from the Site.- As part of this
new plan, a new cluster of wells, consisting of two new
wells at different depths, will be installed between
existing clusters CW-6 and CW-7.
2. Landfill Owner's Role in Implementing the Remedy
Citizens feel strongly that the cleanup would not be
conducted thoroughly by the landfill owner. In particular,
citizens are concerned about the landfill owner possibly
operating the landfill gas treatment system.
According to the law, EPA must negotiate with the
responsible parties for conducting the remedial action. If
the responsible parties agree to implement the selected -
remedy in accordance with CERCLA, EPA will monitor the
design and construction to insure that it is protective of
public health and the environment. Furthermore, the
selected remedy includes an air monitoring program to insure
that during operation the selected remedy remains
proteqtive.
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ATTACHMENT A
COMMUNITY RELATIONS ACTIVITIES
AT THE
LANDFILL AND RESOURCE RECOVERY SITE
IN NORTH SMITHFIELD, RHODE ISLAND
Community relations activities conducted at the Landfill and
Resource Recovery Superfund Site (L&RR Site) have included'the
following:
o 1983 — EPA released a community relations plan describing
citizen concerns about the L&RR Site and outlining a program
to address these concerns and to keep citizens informed
about and involved in Site activities.
o October 1986 — EPA revised the community relations plan to
reflect changes in the level of community concern and to
plan activities designed to meet new community needs.
o January 1987 — EPA held an informational meeting to
present to the community EPA's plans for a Remedial
Investigation and Feasibility Study (RI/FS) at the L&RR
Site.
o July 1988 — EPA arranged for the publication of two public
notices in the Providence Journal and the Woonsocket Call
announcing a public informational meeting and describing
EPA's Proposed Plan for addressing contamination at the L&RR
Site.
o July 1988 — EPA mailed the Proposed Plan announcing EPA's
preferred alternative for addressing contamination at the
L&RR Site to all parties on EPA's site mailing list. .
o July 19, 1988 — EPA held an informational public meeting to
discuss the results of the RI/FS and to present EPA's
Proposed Plan for the Site.
o July 20 - September 2, 1988 — EPA held a six-week public
comment period to accept public comments on the FS
alternatives and the Proposed Plan. The six week comment
period included a three-week extension that EPA held to
allow additional time for interested parties to participate
in the remedy selection process.
o August 10, 1988 — EPA held an informal public hearing to
accept oral comments on the remedial alternatives evaluated
in the FS and on EPA's Proposed Plan.
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APPENDIX B
ADMINISTRATIVE RECORD INDEX
Landfill & Resource Recovery Site
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APPENDIX C
STATE CONCURRENCE LETTER
Landfill & Resource Recovery Site
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STATE OF RHODE ISLAND AND PROVIDENCE PLANTATIONS
Department of Environmental M*n«ctm«nt
OFFICE OF THE DIRECTOR
9 Hayn SttMl
Providence. !U. 02908
September 21, 1988
Mr. Michael Deland
E.P.A. Region I
J.F. Kennedy Federal Building
Boston, Massachusetts 02203
Dear Mr. Deland:
I am writing concerning EPA'S proposed plan for remediation
at the Landfill and Resource Recovery Site (L&RR) in North
Smithfield, Rhode Island.
This Department concurs with those portions of the proposed
plan which are consistent with the closure requirements
outlined in the 1988 Solid waste Consent Order and Agreement
between RIDEM and L&RR, Inc. We understand your laws and
regulations may require more stringent remedial actions and it
appears the additional components of your proposed remedy/
although more protective, are not inconsistent with the closure
measures required by the State's consent agreement.
Very truly yours,
Robert L. Bendick, Jr,
Director
RLB/ms
cc: Torn Gate
0652B
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