943543
East Troy Contaminated Aquifer
Superfund Site
Troy, Miami County, Ohio
Interim Record of Decision
for
Source Area Cleanup
U.S. Environmental Protection Agency, Region 5
77 West Jackson Boulevard
Chicago, IL 60604
September 2018
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TABLE OF CONTENTS
Section Page
LIST OF ACRONYMS AND ABBREVIATIONS iv
PART 1: THE DECLARATION 1
1.1 SITE NAME AND LOCATION 1
1.2 STATEMENT 01 BASIS AM) PURPOSE 1
1.3 ASSESSMENT OF THE SITE 1
1.4 DESCRIPTION OF THE SELECTED INTERIM REMEDY 1
1.5 STATUTORY DETERMINATIONS 3
1.6 ROD DATA CERTIFICATION CHECKLIST 3
1.7 SUPPORT AGENCY ACCEPTANCE 4
1.8 AUTHORIZING SIGNATURE 4
PART 2: DECISION SUMMARY 6
2.1 SITE NAME, LOCATION, AND BRIEF DESCRIPTION 6
2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES 6
2.3 COMMIMTY PARTICIPATION 8
2.4 SCOPE AM) ROI.li 01 OPERABLE UNIT 9
2.5 SITE CHARACTERISTICS 9
2.5.1 Conceptual Site Model 9
2.5.2 Geologic and Hydrogeologic Setting 9
2.5.3 Summary of the Remedial Investigation 11
2.5.3.1 Soil 11
2.5.3.2 Groundwater 13
2.5.3.3 Soil Vapor and Air Samples 15
2.6 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES 17
2.7 SUMMARY OF SITE RISKS 17
2.7.1 Summary of Human Health Risk Assessment 18
2.7.2 Summary of Ecological Risk Assessment 23
2.7.3 Basis for Taking Action 24
2.8 INTERIM REMEDIAL ACTION OBJECTIVES 24
2.8.1 East Water Street Soil RAOs 24
2.8.2 Residential Plume Source Area RAOs 25
2.8.3 Vapor Intrusion RAOs 26
2.9 DESCRIPTION OF INTERIM ALTERNATIVES 27
2.9.1 Interim S oil Alternatives 27
2.9.2 Interim Groundwater Alternatives 29
2.9.3 Interim Soil Vapor Intrusion Alternatives 34
2.10 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 36
2.10.1 Overall Protection of Human Health 37
2.10.2 Compliance with Applicable or Relevant and Appropriate Requirements 38
2.10.3 Long-Term Effectiveness and Permanence 38
2.10.4 Reduction of Toxicity, Mobility, or Volume through Treatment 39
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2.10.5 Short-Term Effectiveness 39
2.10.6 Implementability 40
2.10.7 Cost 40
2.10.8 State/Support Agency Acceptance 41
2.10.9 Community Acceptance 41
2.11 PRINCIPAL THREAT WASTE 41
2.12 SELECTED INTERIM REMEDY 42
2.12.1 Summary of the Rationale for the Selected Interim Remedy 42
2.12.2 Detailed Description of the Selected Interim Remedy 42
2.12.3 Cost Estimate for Selected Interim Remedy 43
2.12.4 Expected Outcomes of the Selected Interim Remedy 44
2.13 STATUTORY DETERMINATIONS 44
2.13.1 Protection of Human Health and the Environment 44
2.13.2 Compliance with Applicable or Relevant and Appropriate Requirements 45
2.13.3 Cost Effectiveness 45
2.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
(or Resource Recovery Technologies) to the Maximum Extent Practicable 46
2.13.5 Preference for Treatment as a Principal Element 46
2.13.6 Five-Year Review Requirements 46
2.14 DOCUMENTATION OF SIGNIFICANT CHANGES 46
PART 3: RESPONSIVENESS SUMMARY 48
3.1 STAKEHOLDER COMMENTS AND LEAD AGENCY RESPONSES 48
3.2 TECHNICAL AND LEGAL COMMENTS 49
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LIST OF FIGURES
Figure 1 Site Location Map
Figure 1-2 City of Troy East and West Well Fields
Figure 2 Site Features
Figure 3 Conceptual Site Model
Figure 4 Residential Plume Area Soil Sample Locations
Figure 5 Hobart Soil Sampling Results
Figure 6 Spinnaker Soil Sampling Results
Figure 7 Residential and East Water Street Plumes Total VOC Concentrations
Figure 8 Residential Plume Source Area
Figure 9 Phase IVI Sampling Locations and Results
Figure 10 Phase IIVI Sampling Locations and Results
Figure 11 Soil Exposure Areas - East Water Street Plume
Figure 12 Groundwater Exposure Areas
Figure 13 Groundwater Treatment Zones - Residential Plume Source Area
Figure 14 Soil Alternative S-2 Proposed Excavation Areas
Figure 15 Soil Alternative S-3 Proposed Excavation and Asphalt Cap Areas
Figure 16 Conceptual Layout of Alternatives RGW-2A, 2B, and 2C
Figure 17 Conceptual Layout of Alternatives RGW-2A and 2B
Figure 18 Conceptual Layout of Alternative RGW-2C
Figure 19 Proposed VI Mitigation Area
LIST OF TABLES
Table 1 Groundwater Screening Levels
Table 2 Compounds Exceeding Groundwater Screening Levels
Table 3 Compounds Exceeding VI Screening Levels
Table 4 Summary of Soil Risks and Hazards - East Water Street Exposure Areas
Table 5 Summary of Groundwater Risks and Hazards in Upgradient Exposure Areas
Table 6 Summary of Groundwater Risks and Hazards in Downgradient Exposure Areas
Table 7 Summary of Vapor Intrusion Risks and Hazards - Upgradient Exposure Areas
Table 8 Soil Remedial Action Levels
Table 9 Vapor Intrusion Remedial Action Levels
APPENDICES
Appendix A - Administrative Record Index
Appendix B - State Concurrence Letter
Appendix C - Cost Estimate for Selected Interim Remedy
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LIST OF ACRONYMS AND ABBREVIATIONS
ARAR
Applicable or Relevant and Appropriate Requirement
BHHRA
Baseline Human Health Risk Assessment
cDCE
cis-l,2-dichloroethene
CERCLA
Comprehensive Environmental Response, Compensation, and Liability
Act of 1980
CFR
Code of Federal Regulations
COC
Contaminant of Concern
COPC
Contaminant of Potential Concern
CSM
Conceptual Site Model
DNAPL
Dense Non-Aqueous Phase Liquid
EA
Exposure Area
EPA
United States Environmental Protection Agency
ERD
Enhanced Reductive Dechlorination
ESD
Explanation of Significant Differences
ETC A
East Troy Contaminated Aquifer
FS
Feasibility Study
FFS
Focused Feasibility Study
GMR
Great Miami River
HI
Hazard Index
ISCO
In-situ Chemical Oxidation
ISCR
In-situ Chemical Reduction
MIP
Membrane Interface Probe
Ohio EPA
Ohio Environmental Protection Agency
NCP
National Contingency Plan
NPL
National Priorities List
O&M
Operations and Maintenance
O.A.C.
Ohio Administrative Code
OU
Operable Unit
PCE
T etrachloroethylene
POTW
Publicly-Owned Treatment Works
PRP
Potentially Responsible Party
RAL
Remedial Action Level
RAO
Remedial Action Objective
RCRA
Resource Conservation and Recovery Act
RI
Remedial Investigation
ROD
Record of Decision
SSD
Sub-slab Depressurization System
TCE
Trichloroethylene
UU/UE
Unrestricted use and Unlimited Exposure
VI
Vapor Intrusion
VOC
Volatile Organic Compound
YD3
Cubic Yards
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INTERIM RECORD OF DECISION
FOR
SOURCE AREA CLEANUP
EAST TROY CONTAMINATED AQUIFER SUPERFUND SITE
TROY, OHIO
PARTI: THE DECLARATION
1.1 Site Name and Location
The East Troy Contaminated Aquifer Superfund Site (ETCA Site or Site) is located in the City of
Troy, Miami County, Ohio approximately 20 miles north of Dayton. The Site's EPA
identification number is OHSFN507962.
1.2 Statement of Basis and Purpose
This Interim Record of Decision (ROD) presents the selected interim remedy chosen by the U.S.
Environmental Protection Agency (EPA) for the ETCA Site. EPA selected the interim remedy
in accordance with the Comprehensive Environmental Response, Compensation, and Liability
Act of 1980 (CERCLA), as amended by the Superfund Amendments and Reauthorization Act of
1986, and, to the extent practicable, the National Contingency Plan (NCP). This decision is
based on the Administrative Record file for the ETCA Site.
The State of Ohio concurs with the selected interim remedy. A letter of concurrence from the
State of Ohio can be found in Appendix B.
1.3 Assessment of the Site
The interim response action selected in this ROD is necessary to protect the public health or
welfare or the environment from actual or threatened releases of hazardous substances into the
environment.
1.4 Description of the Selected Interim Remedy
This Interim ROD addresses two groundwater contamination source areas at the ETCA Site: (1)
the Residential Plume source area located within a predominately residential area southwest of
East Main Street and (2) the East Water Street soil source areas located within a mixed
industrial, residential and commercial area along East Water Street. This Interim ROD involves
source treatment within the groundwater aquifer at the Residential Plume source area and
excavation of soil at the East Water Street soil source area. This interim remedy does not include
treatment of the East Water Street groundwater plume. Final remedies for residual
contamination in the Residential and East Water Street groundwater plumes will be addressed in
a future ROD after assessing the effectiveness of the interim action and collecting additional
groundwater data. Both of the contamination source areas and their associated residual
groundwater plumes are collectively known as Operable Unit 1 (OU1).
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The selected interim remedy in this ROD is a combination of Soil Alternative S-2 (Excavation
with Off-Site Disposal) for the East Water Street soil source areas; Groundwater Alternative
RGW-2C (In-Situ Treatment Using Chemical Oxidation (ISCO)) for the Residential Plume
source area; and Vapor Intrusion Alternative VI-2 (Installation of Sub-slab Depressurization
Systems (SSDs)) for the Residential Plume source area.
The major components of the interim remedy selected for the East Water Street soil source areas
(Soil Alternative S-2) include:
• Excavation of approximately 9,110 cubic yards (yd3) of contaminated soils from the
area behind the former Hobart Cabinet loading dock and excavation of approximately
753 yd3 of contaminated soils under the asphalted portion of the Spinnaker Coatings
western parking lot;
• Collection of confirmation samples from excavated areas to ensure soil cleanup levels
are met;
• Loading of contaminated soils into dump trucks with transportation to an off-Site
licensed landfill for disposal;
• Backfill of excavated areas with gravel or clean soil; and
• Dust suppression during excavation and loading of the dump trucks and covering of
dump trucks with a tarp to minimize dust generation and minimize risks to the
community.
The major components of the interim remedy selected for the Residential Plume source area
(Groundwater Alternatives RGW-2C and Vapor Intrusion Alternative VI-2) include:
• In-situ chemical oxidation of the Residential Plume source area and groundwater
downgradient of the source area (referred to as the "groundwater treatment area") from
Walnut to Union Streets;
• Groundwater monitoring to ensure cleanup goals (70 to 90 percent reduction in dissolved
total Volatile Organic Compound (VOC) mass throughout the treatment area) are met and
to ensure the City of Troy East Well Field is not adversely impacted. Any reduction of
VOC mass at or beyond 70 percent will be considered successful for this interim action.
EPA expects actual reduction of the VOC mass to be in the range of 70 to 90 percent,
with any additional reduction serving as a greater success;
• Installation of SSDs (similar to radon mitigation systems) at approximately 156 buildings
located above the groundwater treatment area, plus an additional two-block buffer to
Frank Street (collectively, from Walnut to Frank Streets); and
• Post-installation verification testing of all SSDs to ensure the systems are operating
properly.
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Principal threat wastes are defined as those source materials considered highly toxic or highly
mobile that generally cannot be reliably contained or would present a significant risk to human
health and the environment should exposure occur. The "principal threat" concept is applied to
the characterization of "source materials" at a Superfund site. A source material includes or
contains hazardous substances, pollutants, or contaminants that act as a reservoir for migration of
contamination to groundwater, surface water or air; or act as a source for direct exposure.
Contaminated (saturated) soils at the Residential Plume source area are assumed to be Non-
Aqueous Phase Liquid (NAPL) and thus, are considered principal threat wastes. The selected
interim remedy will use ISCO to address principal threat wastes by treating the highly
contaminated source materials at the Residential Plume.
1.5 Statutory Determinations
The selected interim remedy is protective of human health and the environment in the short-term
and is intended to provide adequate protection until a final Site-wide groundwater remedy is
successfully implemented and achieves remedial action objectives, complies with federal and
State requirements that are applicable or relevant and appropriate to this limited-scope action,
and is cost-effective. This interim action is consistent with the statutory mandate for permanence
and treatment to the maximum extent practicable. This interim action does utilize treatment as a
principal element of the remedy that will permanently and significantly reduce the toxicity,
mobility, or volume of hazardous substances, pollutants, or contaminants.
Because this remedy will result in hazardous substances, pollutants, or contaminants remaining
on-Site above levels that allow for unlimited use and unrestricted exposure, a statutory review
will be conducted within five years after initiation of remedial action to ensure that the selected
interim remedy is protective of human health and the environment. Review of this interim
remedy will be ongoing as EPA continues to develop final remedial alternatives for the Site-wide
groundwater.
1.6 ROD Data Certification Checklist
The following information is included in the Decision Summary section of this Interim ROD.
Additional information can be found in the Administrative Record file for the Site.
Information
ROD Section
Contaminants of concern (COCs) and their respective concentrations
2.7.1
Baseline risk represented by the COCs
2.7.1
Cleanup levels established for COCs and the basis for these levels
2.8
How source materials constituting principal threats are addressed
2.11
Current and reasonable anticipated future land use assumptions and current
and potential future beneficial uses of groundwater used in the baseline risk
assessment and Interim ROD
2.6
Estimated capital, annual operation and maintenance (O&M), and total present
worth costs, discount rate, and the number of years over which the interim
remedy cost estimates are projected
2.12.3
Key factor(s) that led to selecting the interim remedy
2.12
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1.7 Support Agency Acceptance
The Ohio Environmental Protection Agency (Ohio EPA), as the support agency for the ETC A
Site, concurs with this Interim ROD. The State's concurrence letter has been added to the
Administrative Record (Appendix B).
1.8 Authorizing Signature
9/20/2018
Douglas Ballotti
Acting Director, Superfund Division
Signed by: DOUGLAS BALLOTTI
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PART 2: DECISION SUMMARY
2.1 Site Name, Location, and Brief Description
The ETC A Site is located in the City of Troy, Miami County, Ohio approximately 20 miles north
of Dayton, Ohio. The ETCA Site includes an approximate 20-square block area of contaminated
groundwater and associated soils extending west from the west bank of the Great Miami River
(GMR) within an area that extends from approximately South Walnut Street on the northwest to
Floral Avenue on the southeast, Canal and Scott streets on the southwest and the GMR on the
northeast. The ETCA Site is located primarily in an older urban, residential, industrial, and
commercial setting. On the west side of the GMR, the entire Site is developed as residential,
industrial, or commercial and is densely constructed and paved. On the east side of the GMR,
the area includes mostly unpaved recreational use areas. See Figure 1 (Site Location Map).
The City of Troy obtains its public water supply from two well fields, the East Well Field and
West Well Field, located approximately 3/4 mile apart, on the east bank of the GMR. Both well
fields draw water from the deeper portions of the sand and gravel deposits that underlie the Site
vicinity. The City of Troy public water system serves a population of approximately 28,000
people. The City's municipal water service area includes the entire ETCA Site and all areas
within the Troy City limits. A City ordinance prohibits potable uses of the groundwater, and all
homes/businesses within the ETCA Site are connected to the public water supply. The East Well
Field is located directly east of the Site and across the GMR, and consists of five production
wells. The aquifer beneath the ETCA Site is designated as a Sole Source Aquifer because it is
the principal source of drinking water for the population in the City of Troy and because there
are no reasonably available alternative drinking water resources. The City's West Well Field is
located 3/4 mile to the northeast of the ETCA Site and across the GMR, and also consists of five
production wells. The locations of the City of Troy East and West Well Fields are shown on
Figure 1-2. Persons interested in information on the West Troy Contaminated Aquifer Site can
obtain that information at https://www.epa.gov/superfund/west-trov-aquifer.
The ETCA Site consists of groundwater contaminated with chlorinated volatile organic
compounds (VOCs), specifically trichloroethene (TCE) and tetrachloroethene (PCE) in a
neighborhood on the east side of Troy, Ohio. Groundwater contamination has adversely
impacted water quality in the local sand and gravel aquifer and indoor air quality in structures
above the groundwater contamination plume through a process called vapor intrusion (VI).
VOCs have been found in Site groundwater, soils, and in indoor air within structures located
above the groundwater contamination.
EPA is the lead agency for the ETCA Site, and Ohio EPA is the support agency.
2.2 Site History and Enforcement Activities
The ETCA Site was first identified in 1988, when cis-l,2-dichloroethene (cDCE) was detected in
the City of Troy's East Well Field. The concentrations detected in the City wells were well
below the levels considered to be a health risk since the concentrations were below EPA Safe
Drinking Water Act (SDWA) Maximum Contaminant Levels (MCLs). Ohio EPA later
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conducted soil gas sampling beneath neighborhood buildings in 2006 and confirmed that VOCs
present in the groundwater were moving up through the soil and into the indoor air of buildings
above the contamination through cracks in foundations. This process is called vapor intrusion.
In response, EPA conducted a time-critical removal action in 2007 and installed Sub-slab
Depressurization Systems (SSDs) (similar to radon mitigation systems) to remove vapors from
16 homes and one school. Subsequently, EPA placed the ETCA Site on the National Priorities
List (NPL) in 2008, making it eligible for investigation and cleanup under EPA's Superfund
program.
In 2010, EPA issued Special Notice Letters to the Potentially Responsible Parties (PRPs) to
conduct the Remedial Investigation (RI) and Feasibility Study (FS) for the ETCA Site.
Negotiations between EPA and the PRPs proved unsuccessful, so EPA conducted the RI/FS as a
CERCLA fund-lead action. From 2010 to 2014, EPA conducted the RI using a phased approach.
Phase 1 sampling, conducted from December 2009 to May 2012, focused on identifying
potential contamination source areas and investigating the nature and extent of contamination.
Phase 2 sampling, conducted from August 2012 to May 2013, focused on collecting additional
data to address Phase 1 data gaps and to further delineate the extent of contamination at the Site.
An additional Phase 2 sampling event, conducted from October 2013 to May 2014, focused on
further characterization of the nature and extent of contamination at the source areas. The RI
sampling results are discussed in Section 2.7 of this Interim ROD. More detailed RI findings are
included in the 2015 Final RI Report (SulTRAC 2015) available in the Administrative Record
for the ETCA Site. EPA completed a Focused Feasibility Study (FFS) report for the ETCA Site
in February 2018.
The Site RI investigation results and EPA's PRP search indicate that two separate groundwater
plumes exist and each originated from different and potentially multiple sources. The RI data
indicate that these separate releases of PCE and TCE to the groundwater resulted in two
groundwater plumes that co-mingle in some areas. See Figure 2 (Site Features) for groundwater
plume locations.
The first groundwater plume, referred to as the "Residential Plume," is located within a
predominately residential area southwest of East Main Street. This plume primarily contains
PCE with lesser amounts of TCE and cDCE. PCE is known to degrade over time to TCE and
cDCE. The RI data documents that the highest PCE concentration, indicating a potential PCE
plume source, is located beneath or immediately northwest of South Walnut Street, roughly mid-
block between East Main and East Franklin Streets. RI data also documents there is no PCE in
groundwater immediately upgradient, or north, from this area.
This data indicates that the South Walnut Street location is a likely source of PCE documented in
the groundwater plume. Historical records indicate that this area was near an alley that ran
behind the "Troy One-Hour Cleaners," a dry cleaner that operated from 1958 to 1979 at 10 East
Main Street. Information also indicates that the Troy One-Hour Cleaners may have occupied
two attached structures (8 and 10 South Walnut), both of which are adjacent to the alley. PCE is
a chemical known to have been used in the dry cleaning process between 1958 and 1979. EPA's
investigation did not identify another establishment at this location that may have used PCE in its
business activity, although the investigation did identify other establishments nearby that may
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have used PCE in their business activities. The release of PCE to groundwater may occur
through spillage to the ground during operations or disposal, and through leakage to soils from
drains and sanitary sewer pipes.
The former dry cleaner building and attached structures were destroyed in a 1979 fire and the
buildings were razed. In 2002, the First Presbyterian Church built an addition completely
covering the footprint of the former dry cleaner building, attached structures and the alley.
The RI documents that the Residential Plume extends about 3/4 mile downgradient
(southeastward) from the source area (Walnut Street vicinity) to the vicinity of Floral Avenue.
Most of the groundwater plume lies in the area between East Main Street on the north and Canal
and Scott Streets on the south.
The second groundwater plume, referred to as the "East Water Street Plume," is located within a
mixed industrial, residential, commercial, and institutional (public buildings such as schools and
school board offices) use area along East Water Street. This plume contains primarily TCE, with
lesser amounts of PCE and cDCE. This plume originates near the northwest corner of the former
Hobart Cabinet Company (301 E Water Street) in close proximity to the loading dock area.
Analytical results from soil samples collected during the RI documented PCE and TCE in
subsurface soil as high as 72,000 (J,g/kg and 89,000 (J,g/kg, respectively. These soil and
groundwater PCE and TCE analytical results support a finding that surface spills and/or dumping
directly onto the ground of PCE/TCE-containing solvents had occurred behind or in the vicinity
of the Hobart loading dock. Sampling data collected during the RI also indicate that chlorinated
VOCs are present in shallow soils and groundwater on the property adjacent to, and
downgradient (southeast) of, the Hobart building at a second industrial facility, formerly known
as Brown-Bridge Industries, Inc. (now Spinnaker Coatings, LLC).
Groundwater data show that the East Water Street Plume extends about '/2 mile downgradient
(southeast) from the source area past Williams Street to Ellis Street (assuming an imaginary line
is drawn from Ellis and Franklin Streets eastward to the west bank of the GMR). This plume is
bounded to the north by the GMR and to the south by East Water Street. In the vicinity of the
eastern terminus of East Water Street, the East Water Street Plume appears to co-mingle with
contamination migrating from the Residential Plume due to the influence of pumping in the
City's East Well Field.
2.3 Community Participation
EPA made the RI and FFS Reports and Proposed Plan for the ETC A Site available to the public
on June 25, 2018. These documents can be found with other pertinent documents in the
Administrative Record file which can be accessed on EPA's web site for the ETC A Site at
www.epa.gov/superfund/east-troy-aquifer. The Administrative Record file is also maintained at
two public repositories: the EPA Region 5 Docket Room, 77 West Jackson Boulevard (7th
Floor) Chicago, Illinois; and the Troy-Miami County Public Library, Local History Branch, 100
W. Main Street, Troy, Ohio.
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EPA published the notice of the availability of these documents in the Troy Daily News on June
15, 2018, and held a public comment period from June 25 to July 25, 2018.
EPA held a public meeting on June 27, 2018 to present the Proposed Plan to the community. A
transcript from this meeting has been added to the Administrative Record file. At this meeting,
representatives from EPA and Ohio EPA answered questions about the Site and the remedial
alternatives. EPA also used this meeting to solicit formal comments on the Proposed Plan.
EPA's response to comments received during the public comment period is included in the
Responsiveness Summary, which is in Part 3 of this Interim ROD.
2.4 Scope and Role of Operable Unit
This interim remedy addresses the Residential Plume source area and East Water Street soil
source area. This interim remedy will be implemented at the two contamination source areas
while EPA develops long-term cleanup options for the Site-wide groundwater contaminant
plumes that have migrated from these source areas downgradient to Floral Avenue (part of the
Residential Plume) and to beyond the eastern terminus of East Water Street and the GMR (East
Water Street Plume). EPA will propose and select a final Site remedy that addresses the
groundwater plumes in a future Proposed Plan and Record of Decision after assessing the
effectiveness of the source control action and collecting additional groundwater data.
2.5 Site Characteristics
2.5.1 Conceptual Site Model
The conceptual site model (CSM) for human health was developed during the RI/FFS to guide
the identification of appropriate exposure pathways and receptors for evaluation in the risk
assessment. Releases of PCE and TCE to the groundwater resulted in two separate groundwater
plumes that co-mingle in some areas. The release of PCE and TCE to the groundwater may have
occurred through spillage to the ground during operations or disposal, and through leakage to
soils from drains and sanitary sewer pipes. A general identification of exposure pathways,
exposure routes, and receptors is illustrated in the CSM in Figure 3.
This interim action is meant to address the risk to human receptors through exposure to PCE and
TCE in soils through two primary routes: (1) inhalation of vapors from subsurface soil that are
brought to the surface as a result of intrusive excavation or landscaping and (2) inhalation of
vapors that migrate from subsurface soil into trench air. The potential receptors to the subsurface
soil include future residents, future industrial/commercial workers and current/future
construction workers. Inhalation of vapors migrating from contaminated groundwater are also
being addressed under this interim action.
2.5.2 Geologic and Hydrogeologic Setting
The geology of the ETCA Site has been extensively characterized. Information regarding the
Site's geology has been drawn from on-Site data gathered during RI Phases I and II, as well as
from previous studies. During the RI, EPA installed and logged 31 soil borings to characterize
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Site geology and to install groundwater monitoring wells. Information gathered from these
locations was supplemented by observations and physical data acquired during Membrane
Interface Probe (MIP) (38 borings) and Waterloo (36 borings) sampling programs, and by logs of
more than 60 shallow borings completed during the soil sampling program. Additional
information was also available from logs of borings installed by Ohio EPA and the City of Troy
prior to the RI.
The ETCA Site is above the deep buried bedrock valley that trends north to south through the
approximate center of the southern half of Miami County and within the area where the present-
day GMR flows. The bedrock valley has been filled with glacial and post-glacial sediments, so
that the present-day surface topography is relatively flat. The subsurface at the Site consists of a
thick sequence of sand, gravel, silt, and clay overlying interbedded shale and limestone bedrock.
Because the unconsolidated materials (sand, gravel, silt, and clay) contain the affected
groundwater zones, the RI investigations were limited to the unconsolidated materials. Bedrock
was not encountered during the RI. The deepest boring installed during the RI was completed in
unconsolidated materials at 130 feet below ground surface (bgs), while the thickness of the
unconsolidated materials extends to a depth of approximately 200 feet.
The below-ground unconsolidated materials are often discussed in terms of three zones, all of
which contain groundwater, (1) the deep sand and gravel zone used for the municipal water
supply ("lower" aquifer), (2) the shallow sand and gravel deposits ("upper" aquifer), and (3) less
permeable fine-grained materials (clays and silts), limited in extent, that occur at all depths, but
in some areas form a localized zone encountered between the "upper" and "lower" sand and
gravel deposits. In general, the upper aquifer is from the water table (12 to 20 feet bgs) to
approximately 40 feet bgs, the middle zone, where present, is generally between 40 and 60 feet
bgs, and the lower aquifer is typically from about 60 feet to about 200 feet bgs. Geological and
contaminant data gathered during the RI indicate that clays and silts of significant thickness are
present in some areas, but are absent in other areas. No distinct horizontal layer fully separates
the sand and gravel units into upper and lower zones consistently across the Site. The depth to
uppermost groundwater at the Site is relatively shallow, typically ranging from approximately 12
to 20 feet bgs, but varies depending on the location and season.
The GMR is hydraulically connected to the upper sand and gravel aquifer. Leakage studies
conducted by the City of Troy indicate that the GMR recharges the upper aquifer and is a losing
stream in the channelized area that lies adjacent to the groundwater contaminant plume and the
East Well Field.
Groundwater flow direction in the upper portion of the aquifer is to the southeast, parallel to the
GMR, with localized and seasonal variations, particularly in the area immediately adjacent to the
GMR and also in the area near the East Well Field. Based on groundwater elevations and studies
conducted by the City of Troy, pumping in the East Well Field has localized influence on the
shallow zone. Groundwater flow in the deeper portions of the aquifer is in the same direction
(southeast) as in the upgradient/northwest part of the Site. However, flow in the deep zone is
more heavily influenced by pumping at the East Well Field, east and south of Union Street.
Groundwater flow between East Main Street and the GMR (southeast of Union Street) appears to
be heavily influenced by pumping from the East Well Field in both the shallow and deep zones.
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2.5.3 Summary of the Remedial Investigation
As discussed above, a RI was conducted at the ETC A Site from the winter of 2010 to the spring
of 2014. The purpose of the RI was to identify all potential source areas contributing to the
groundwater contamination at the Site and to delineate the nature and extent of contamination at
these areas. The significant findings and conclusions from the Site characterization activities
completed during the RI for soil, groundwater, and vapor intrusion are summarized below.
Additional detail about Site investigations is provided in the 2015 Final RI Report.
2.5.3.1 Soil
EPA characterized soil contamination at the ETCA Site during the Phase I and Phase II RI
through analysis of approximately 212 soil samples collected within four general areas at the Site
including the Residential Plume, the Hobart and Spinnaker properties along East Water Street,
and residential properties between Hobart and Spinnaker. All samples were analyzed for VOCs.
A subset of the soil samples was also analyzed for metals, polychlorinated biphenyls (PCBs),
pesticides, and semi-volatile organic compounds (SVOCs) to determine whether additional
significant contributing source areas are present at the Site. No metals, PCBs, pesticides, or
SVOCs were identified as contaminants of potential concern (COPC) in soil based on
comparison to risk-based screening levels. Therefore, only VOC contamination is discussed
below.
Analytical soil results were compared to EPA: (1) residential and industrial soil Regional
Screening Levels (RSLs) for direct contact protection and (2) RSLs for protection of
groundwater. The RSLs take into consideration exposure from incidental ingestion of, dermal
contact with, and inhalation of particulates and vapors from surface and subsurface soil.
Screening levels are conservative risk-based values used as a starting point for screening
detected contaminants and determining COPCs that warrant further evaluation in the baseline
human health risk assessment (BHHRA).
COPCs were identified based upon compounds exceeding either residential or industrial
screening levels for direct contact protection. COPCs were not identified based upon
exceedances of protection of groundwater RSLs. Protection of groundwater RSLs are the
concentration of contaminants in soil that will prevent exceedances of SDWA MCLs even if
leaching to groundwater occurs. The BHHRA, which is discussed in subsequent sections,
determines the actual risks and hazards and the need for action to address the contamination.
Residential Plume
Approximately 50 soil samples were collected from 17 locations within the residential area
between Walnut and Union Streets and East Main and Canal Streets. Of the 14 VOCs detected
in soil, none exceeded residential or industrial direct contact RSLs. Four chemicals (PCE, TCE,
toluene, and benzene) exceed the RSL for the protection of groundwater. PCE exceeded the
RSL for protection of groundwater in 19 samples, TCE in four samples, and benzene and toluene
in one sample each. See Figure 4 for Residential Plume soil sample locations.
11
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Hobart Property
Approximately 63 soil samples were collected from 21 locations around the Hobart building and
two locations within the basement and garage area that underlies the Hobart loading dock. Of
the 23 VOCs detected in soil, 13 VOCs exceeded one or more Site RSLs. Four of these VOCs
(PCE, TCE, 1,1,2-trichloroethane (1,1,2-TCA) and benzene) exceeded the residential or
industrial soil direct contact RSLs (in addition to the protection of groundwater RSLs). PCE,
benzene, and 1,1,2-TCA exceeded the residential and industrial direct contact RSLs in one
sample, while TCE exceeded the residential direct contact RSLs in 26 samples and the industrial
direct contact RSLs in 19 samples. The highest concentrations of VOCs were detected near the
loading dock area (referred to as "EA-1"). The highest concentrations of TCE (89,000; 40,000;
and 20,000 micrograms per kilogram ([j,g/kg) were detected in subsurface soil samples HOB-3,
SB315, and SB317, respectively. The highest concentrations of PCE (72,000 and 28,000 (J,g/kg)
were also detected in subsurface soil samples (SB316 and HOB-3, respectively) collected from
approximately 4 feet bgs behind the loading dock. VOCs were detected in surface soils but at
concentrations below direct contact RSLs. See Figure 5 for Hobart soil sample locations and
results.
Spinnaker Property
Approximately 93 soil samples were collected from 22 locations throughout the Spinnaker
property. Of the 20 VOCs detected in soil, 10 VOCs exceeded the protection of groundwater
RSLs. Only TCE exceeded the residential direct contact RSL (15 times) and direct contact
industrial RSL (4 times). The highest concentrations of VOCs were detected in samples near the
west end of the main Spinnaker parking lot (referred to as "EA-6"), which is currently paved with
asphalt. In this area, TCE was detected above the residential and industrial direct contact RSLs
and the protection of groundwater RSLs in subsurface soil samples from borings SPIN 1 and
SB301, with the maximum concentrations of 22,000 and 12,000 (J,g/kg at a depth of 2 to 4 feet bgs.
TCE also exceeded the residential direct contact RSL in samples collected from borings near the
west and north walls of the Spinnaker building (SB309, SB310, SB311, SB312, SB313, and
SB314). Soil samples from two of the borings (SB311 and SB313) also exceeded the protection of
groundwater RSL and the industrial direct contact RSL, with the highest concentrations of TCE in
a subsurface soil sample (SB311) at 2,300 |ig/kg at a depth of 4 feet bgs and in a surface sample at
SB313, with a maximum concentration of TCE of 1,900 (J,g/kg. See Figure 6 for Spinnaker soil
sample locations and results.
Area between Hobart and Spinnaker Property
Soil samples were collected from the four residential properties located between the Hobart and
Spinnaker buildings and analyzed for VOCs only. The VOCs detected in soil were acetone and
methyl acetate; however, neither exceeded residential direct contact or the protection of
groundwater RSLs. No further action is required in this area as part of the interim action.
12
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2.5.3.2 Groundwater
EPA characterized groundwater contamination at the ETCA Site through the collection and
analysis of approximately 400 groundwater samples during Phase I, Phase II, and Additional
Phase II sampling. Phase I was conducted from 2010-2012; Phase II in 2012-2013; and
Additional Phase II in 2013-2014. All samples were analyzed for VOCs, with samples from
select locations also analyzed for SVOCs, pesticides, PCBs, and total and dissolved metals.
Analytical results were compared to EPA SDWA MCLs, EPA Tapwater RSLs, and EPA vapor
intrusion screening levels (VISL), as noted in the table below.
Table 1 - Groundwater Screening Levels (wg/L)
Compound
MCL
Tapwater RSL
VISL
Tetrachloroethene (PCE)
5
4.10
15
Trichloroethene (TCE)
5
0.280
1.20
C7.V-1,2-Dichlorocthcnc (cDCE)
70
3.60
NE
Chloroform
80
0.22
0.81
Bromodichloromethane
80
0.13
0.88
Dibromochloromethane
80
0.17
3.20
NE - not established
Results of the RI groundwater sampling indicate that six VOCs (PCE, TCE, cDCE, chloroform,
bromodichloromethane, and dibromochloromethane) were detected at concentrations above one
or more of the Site screening levels, as shown below. Only PCE and TCE were detected above
the SDWA MCL.
Table 2 - Compounds Exceeding Groundwater Screening Levels
Compound
MCL
Tapwater RSL
VISL
Tetrachloroethene (PCE)
¦
¦
¦
Trichloroethene (TCE)
¦
¦
¦
c/.s-1,2-Dichlorocthcnc (cDCE)
¦
NE
Chloroform
¦
¦
Bromodichloromethane
¦
¦
Dibromochloromethane
¦
¦
NE -not established
This interim action is intended to remediate two known high-level contamination areas {i.e., a
high contaminant concentration area within the Residential Plume and a high contaminant
concentration area within the soils at the East Water Street soil source area) that serve as sources
of contamination to the broader groundwater plumes at the ETCA Site. The interim remedy
involves in-situ treatment of the Residential Plume groundwater aquifer only within the Plume's
contaminant source area; and for the East Water Street Plume, only excavation and off-Site
disposal of contaminated soils at the East Water Street soil source area. The RI groundwater
discussion below pertains only to the Residential Plume because in-situ treatment is not being
proposed for the East Water Street Plume at this time. Final remedies for the Residential and
13
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East Water Street residual groundwater plumes will be presented in a separate Proposed Plan and
ROD in the future.
Residential Plume Observations and Conclusions
The RI groundwater investigation indicated that the highest concentrations of VOCs (primarily
PCE, with lesser amounts of TCE and cDCE) were found in samples collected along Walnut
Street directly downgradient from the former locations of the far rear (southwest) end of 10 East
Main Street and the attached structures at 8 and 10 South Walnut Street. These locations are
adjacent to two sewer laterals that connect (or formerly connected) structures in this area to the
Walnut Street sewer. Groundwater data indicate that contamination extends to depths greater
than 80 feet bgs in this area and immediately downgradient.
Based on the Waterloo Advanced Profiling System groundwater profiling results, the highest
concentrations of PCE were detected in borings drilled along the west side of Walnut Street,
which was the closest location to the former dry cleaner where sampling could feasibly be
completed. The highest concentrations of PCE detected were 2,740 [j,g/L (34 feet bgs), 2,400
[j,g/L (39 feet bgs), and 3,560 [j,g/L (44 feet bgs). The relatively narrow width of the most
concentrated and deepest part of the plume suggests an original source that was relatively small
in lateral extent - such as a point discharge/release - with subsequent rapid migration primarily
downward and horizontally downgradient. See Figure 7 showing total VOC concentrations in
groundwater at the Residential Plume. Total VOC concentrations include all three compounds,
PCE, TCE, and cDCE. Figure 8 also shows the plan and profile views of contamination at the
Residential Plume source area.
Dense non-aqueous phase liquid (DNAPL) was not observed in any groundwater samples from
monitoring wells in the Residential Plume source area. However, studies published by EPA and
various other sources have noted the presence of DNAPL at other sites with similar dissolved
phase VOC concentrations as those observed in the ETCA Residential Plume source area. Thus,
for purposes of the FFS, EPA conservatively assumed that DNAPL could be present in the
Residential Plume source area. Additional sampling will be conducted during this interim
action's Remedial Design (RD). If found, EPA will address zones of significantly higher
contaminant concentrations, or DNAPL, by targeting remedy injections at the location and depth
where DNAPL is present.
According to EPA guidance, the presence of DNAPL in groundwater is considered "source
material." "Source material" includes material that contains hazardous substances, pollutants, or
contaminants that acts as a reservoir for migration of contaminants to groundwater. At the
ETCA Site, PCE-contaminated source material represents a principal threat as PCE is highly
mobile in groundwater at the Site. This is apparent as PCE-contaminated groundwater is present
over 3/4 mile downgradient from the Residential Plume source area. This also indicates the
Residential Plume source area continues to serve as an on-going source of PCE contamination to
Site groundwater.
14
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2.5.3.3 Soil Vapor and Air Samples
EPA evaluated the VI pathway by collecting soil vapor and air samples (sub-slab, indoor air, and
ambient air) during three phases of the RI. Phase I VI monitoring was performed in January
2012; Phase II in August 2012; and the Additional Phase IIVI monitoring was conducted in
April 2013. Analytical results were compared to EPA residential and commercial VISLs. Most
Phase I locations were resampled during Phase II, along with additional locations. Therefore,
some locations were sampled during both phases, and some were sampled during only one phase.
Several property owners declined access, so the sample locations chosen partially depended on
access, as well as their location relative to the groundwater plumes.
During the Phase IVI sampling, sub-slab and indoor air samples were collected at 16 residential
and 2 commercial locations. VOCs detected above indoor air or sub-slab VISLs include PCE,
chloroform, carbon tetrachloride, benzene, 1,3-butadiene, 1,4-dichlorobenzene, 1,2-DCA,
bromodichloromethane, TCE, alpha-chlorotoluene, ethyl benzene, and 1,2,4-trichlorobenzene.
See Figure 9 for Phase IVI sample locations and results.
Phase IIVI samples were collected at 22 residential and 3 commercial locations. VOCs detected
above indoor air or sub-slab SLs include PCE, chloroform, carbon tetrachloride, benzene, 1,3-
butadiene, 1,4-dichlorobenzene, 1,2-DCA, bromodichloromethane, TCE, ethyl benzene, 1,2-
dichloropropane, dibromochloromethane, and 1,2-dibromomethane. See Figure 10 for Phase IIVI
sample locations and results.
A summary of Phase I and IIVI results exceeding Site SLs is provided in the table below.
Table 3 - Compounds Exceeding VI Screening Levels
Exceeded Sub-
Exceeded
\ "JL
slab SL
I u do or ail SL
Tetrachloroethene [PCE)
¦
¦
Chloroform
¦
¦
Benzene
¦
¦
1,4-Dichlorobenzienfi
¦
¦
1,2-DicbJoroethane (DCA)
¦
¦
BromodichlorometlisLne
¦
¦
Etlivlbenzene
¦
¦
Carbon tetrachloride
¦
1,3 -Butadiene
¦
1 ,,2-Dichloropropane
¦
Trichloroetkene (TCE)
¦
1 n2,4-T richlorobenzene
¦
Dibromochloroniediane
¦
1,,2-Dibromoe thane
¦
Alpha-Chlorotoluene (benzyl chloride)
¦
15
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Vapor Intrusion Conclusions
Results from locations sampled during both Phase I and Phase II were generally consistent
regarding compounds detected and locations where indoor air and/or subslab SLs were exceeded.
Phase II summer sample results exceeded applicable SLs only at the same locations where results
had exceeded applicable SLs during the Phase I winter samples, collected in January 2012.
Several property owners at locations sampled during Phase I declined access for Phase II
sampling, and therefore, no Phase II summer data are available for these locations. Results from
Additional Phase II locations sampled in April 2013 were used to supplement previous Phase I
and II results.
In general, the extent of VI contamination appears consistent with the alignment of the
groundwater contaminant plumes, with the highest VOC concentrations detected in areas close to
the axes of the groundwater plumes. For this reason, the upgradient boundary of the area
impacted by contaminants in soil vapor is near South Walnut Street, and the lateral boundaries of
the area are approximated by East Main Street and East Canal Street. The farthest downgradient
structure in the area of the Residential Plume where access for sampling was granted was on East
Canal Street between Counts and Frank Streets. The Residential PCE groundwater plume is
located beneath this structure and extends approximately four to five blocks farther downgradient
from this location.
Only PCE, TCE, chloroform, bromodichloromethane, and dibromochloromethane exceeded SLs
in sub-slab or indoor air samples and were also detected in groundwater at concentrations above
their VISLs. These results indicate a correlation between these VOCs in groundwater and in VI
samples. It should be noted that chloroform, bromodichloromethane, and
dibromochloromethane are commonly associated with dechlorination of municipal potable water
and thus are typically found in both potable water supplies and wastewater in sanitary sewers.
They are not believed to be associated with the sources of the groundwater contamination at the
ETC A Site.
Detections of chemicals above the VISL in groundwater, sub-slab samples, and indoor air
samples indicate that the VI pathway may be complete. Given the presence of PCE in these
three media (as well as frequent detections of TCE in groundwater and sub-slab samples), the VI
pathway may be complete at locations that directly overlie the groundwater plumes. Chloroform
is also present but, as previously discussed, is most likely due to leakage from water and sewer
lines in the area. Other VOCs detected in soil vapor and indoor air include benzene, 1,2-
dichloroethane, and 1,4-dichlorobenzene. However, the connection between these chemicals in
groundwater, sub-slab and indoor air samples is not completely demonstrated. Since these
VOCs exceeded Site screening levels, EPA further evaluated these VOCs in the human health
risk assessment, but EPA did not list these as COCs for remediation because they are not
considered Site-related.
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2.6 Current and Potential Future Land and Resource Uses
The Site is composed of mixed residential, commercial, and industrial area served by public
water supply wells, in the deeper uncontaminated aquifer. According to the zoning board of
Miami County, Ohio, the Site is currently zoned for residential and commercial/industrial usage.
The GMR is used for a variety of recreational activities such as fishing, wading, and kayaking
and canoeing during periods of greater water flow (springtime). There are also recreational trails
along the east side of the GMR (across from the Site).
All properties at the ETC A Site are connected to the City of Troy's municipal water supply. The
City obtains its public water supply from two well fields, the East Well Field and West Well
Field, which draw water from the deeper portions of the sand and gravel deposits that underlie
the Site vicinity. The City of Troy system serves a population of at least 28,000 people. The
aquifer beneath the ETCA Site is designated as a Sole Source Aquifer because it is the principal
source of drinking water for the population in the City of Troy.
The future use of land at the Site is also expected to be residential and commercial/industrial.
However, non-residential portions of the ETCA Site (such as the Hobart Cabinet and Spinnaker
Coatings properties) could be redeveloped for residential use in the future.
2.7 Summary of Site Risks
As part of the RI/FFS, EPA conducted a BHHRA to determine the current and future effects of
contaminants on human health and the environment. According to the zoning board of Miami
County, Ohio, the Site is currently zoned for residential and commercial/industrial usage.
Therefore, this is the current and reasonably anticipated future land use for the Site. In addition,
the potential future use of groundwater will be a drinking water source for the community once
safe cleanup levels have been achieved. Hence, the BHHRA focused on health effects for both
children and adults, in several different settings, that could result from current and future direct
contact with:
1) contaminated soils (e.g., ingestion, dermal contact, and inhalation of particulates) and
2) contaminated groundwater through ingestion, dermal contact, and inhalation of volatile
contaminants via household use and via vapor intrusion of soil vapor into buildings.
The BHHRA also considered exposures to on-Site industrial/commercial workers and on-Site
construction and utility workers. These workers could be exposed via all the above exposure
routes. In addition, on-Site construction and utility workers could also be exposed via dermal
contact with groundwater seeping into trenches and inhalation of VOCs inside construction
trenches.
It was assumed that non-residential portions of the ETCA Site could be redeveloped for
residential use in the future. Therefore, EPA evaluated a hypothetical future on-Site residential
exposure scenario to determine whether residential use of the former Hobart Cabinet EA-1 area
and Spinnaker EA-6 area would result in risks and hazards above acceptable standards. Under
17
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this scenario, residents were assumed to be exposed to Site-related constituents in surface soil,
subsurface soil, and potable groundwater. In addition, hypothetical residents were also assumed
to be exposed to vapors in indoor air that migrate through building sub-slab soil via diffusion and
advection.
2.7.1 Summary of Human Health Risk Assessment
A BHHRA estimates potential human health risks posed by a site if no cleanup action is taken.
It provides the basis for taking action and identifies the contaminants and exposure pathways that
need to be addressed by the remedial action. This section of the Interim ROD summarizes the
results of the baseline risk assessment for this Site.
The Site BHHRA evaluated the potential risks and hazards associated with exposure to Site-related
COPCs from contaminated groundwater, soils and indoor air. Four human receptors were
evaluated: current and future residents, current and future industrial/commercial workers, current
and future construction workers, and current and future utility workers.
EPA considers both cancer risk and non-cancer hazards. The likelihood of any kind of cancer
resulting from exposure to carcinogens at a Superfund site is generally expressed as an upper
bound probability, such as a "1 in 10,000 chance" (expressed as 1 x 10"4). In other words, for
every 10,000 people exposed, one extra cancer may occur as a result of exposure to Site
contaminants. For non-cancer hazards, EPA calculates a 'hazard index." The key concept is that a
"threshold level" (measured usually as a hazard index of less than 1) exists below which non-
cancer health effects are no longer predicted. EPA's acceptable risk range is defined as a range
from 1 xlO"6 to 1 x 10"4 and an HI of less than or equal to 1. Generally, remedial action is
warranted at a site if cancer risks exceed 1 x 10"4 and/or if non-cancer hazards exceed an HI of 1.
To calculate cancer and non-cancer risks to human health from exposure to Site-related COPCs in
soil and groundwater, both soil and groundwater areas were divided into Exposure Areas (EAs), as
discussed below.
Soil
The Hobart and Spinnaker properties were divided into EAs to evaluate potential exposure to Site-
related COPCs in soil. The criteria used to select the EAs were current and anticipated future land
use and the presence or absence of a barrier preventing exposure to soil under current land
conditions. The six soil East Water Street EAs are shown in Figure 11 and are summarized below:
• Exposure Area 1- includes the northwest corner of the Hobart property including the
loading dock. This area is currently unpaved.
• Exposure Area 2- consists of the remainder of the Hobart property and a grass-covered area
in the northeastern corner of the property.
• Exposure Area 3- consists of the East Water Street residents (four homes in total) located
between Hobart and Spinnaker properties. This area is grass covered.
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• Exposure Area 4- includes the Spinnaker parking lot, with the exception of a narrow
section (Exposure Area 6) immediately southeast of and adjacent to Exposure Area 3. This
area is currently paved with asphalt.
• Exposure Area 5- the unpaved, grass-covered area immediately northeast of the Spinnaker
building.
• Exposure Area 6- this area consists of the narrow portion of the Spinnaker parking lot,
immediately southeast of and adjacent to Exposure Area 3. This area is currently paved
with asphalt.
The results of the BHHRA as they pertain to the interim remedy soil source areas are discussed
below.
The BHHRA indicated that contaminant concentrations in East Water Street soil resulted in a
cancer risk below or within EPA's acceptable risk range of 1 x 10"6 to 1 x 10"4 for all EAs. The
non-cancer HI for subsurface soil (driven by TCE) in EA-1 (Hobart loading dock) was greater than
1 based on the hypothetical, future on-Site resident (inhaling vapors from contaminated soil) and
future industrial/commercial worker (inhalation pathway) receptors. The non-cancer HI for
subsurface soil (driven by TCE) in EA-6 (narrow portion of Spinnaker parking lot) was also
greater than 1 based on the hypothetical, future on-Site resident (inhalation pathway) receptor. The
table below summarizes the cancer risk and non-cancer hazards for the East Water Street EAs.
The table only shows cancer risks greater than 1 x 10"6 or non-cancer hazards greater than (>) 1.
Table 4 - Summary of Soil Risks and Hazards for East Water Street Exposure Areas
Exposure
Area
Receptor
Calculated
Cancer Risks
Calculated
Non-Cancer
Hazards (HI)
Risk
Drivers
Exposure
Route
EA-1
Future Resident
2.4 x 10"6 Surf*
2.9 x 10"5Sub**
< 1 Surf
7.3 Sub
TCE (Sub)
Inhalation of
vapors from
subsurface soil
that is brought
to surface as a
result of
intrusive
excavation or
landscaping.
Future
Industrial/Commercial
Worker
3.8 x 10"7 Surf
4.7 x 10"6 Sub
0.12 Surf
1.6 Sub
TCE (Sub)
Inhalation of
vapors from
subsurface soil
that is brought
to surface as a
result of
intrusive
19
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excavation or
landscaping.
EA-1
Current/Future
Construction Worker
5.8 x 10"8 Sub
1.8 Sub
TCE (Sub)
Inhalation of
vapors that
migrate from
subsurface soil
into trench air.
EA-2
Cumulative soil cancer risks less than or within risk range and non-cancer HI<1 for
all receptors.
EA-3
No Soil COCs identified.
EA-4
Cumulative soil cancer risks <10"6 and non-cancer HI<1 for all receptors.
EA-5
Cumulative soil cancer risks less than or within risk range and non-cancer HI<1 for
all receptors.
EA-6
Future Resident
9.2 x 10"6 Sub
2.1 Sub
TCE (Sub)
Inhalation of
vapors from
subsurface soil
that are brought
to surface
during intrusive
excavation or
landscaping.
* Surf - surface soil (0-6 inches bgs)
** Sub - subsurface soil (deeper than 6 inches bgs)
Groundwater
The Residential and East Water Street groundwater plumes were divided into up- and down-
gradient EAs to evaluate potential exposure to Site-related COPCs in groundwater via ingestion of
and dermal contact with groundwater used as a source of potable water and via inhalation of
vapors released from potable use activities {i.e., showering and washing dishes and clothes). The
upgradient EAs represent the areas of highest groundwater contamination and the downgradient
EAs represent the less contaminated part of the plume. For the Residential Plume, the upgradient
EA extends from Walnut Street to Frank Street and the downgradient EA extends from Frank
Street to Floral Avenue. For the East Water Street Plume, the upgradient EA extends from Clay
Street to Crawford Street and the downgradient EA extends between Union and Oak Streets to
about Ellis Street (if this street were extended to the GMR). See Figure 12 for groundwater EAs.
The results of the BHHRA as they pertain to the groundwater interim remedy are discussed below.
The BHHRA indicates that contaminant concentrations in groundwater resulted in a cancer risk
slightly exceeding EPA's acceptable risk range of 1 x 10"6 to 1 x 10"4 at both upgradient plume
areas assuming future residential potable groundwater use: Residential Plume Upgradient (2.0 x
10"4) and East Water Street Plume Upgradient (1,4E x 10"4). The non-cancer HI for groundwater
20
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(driven by TCE and PCE) are 2 to 5 times higher at Residential Plume - Upgradient compared
with East Water Street Plume - Upgradient: Future residents (39 versus 6.8), current
industrial/commercial worker (1.5 versus less than 1), future industrial/commercial worker (8.8
versus 1.5), current and future construction worker (20 versus 7.5), and current and future utility
worker (1.5 versus less than 1).
The BHHRA also indicates that cumulative groundwater risks are similar and less than or within
EPA's acceptable risk range of 1 x 10"6 to 1 x 10"4at both downgradient plume areas. Maximum
cumulative groundwater risks, assuming future residential potable groundwater use (ingestion,
dermal and inhalation), were 1.1 x 10"5 at East Water Street Plume- Downgradient and 1.3 x 10"5 at
Residential Plume -Downgradient. The non-cancer HI are similar for the downgradient plume
areas and exceed 1 only for residents (HI =1.4 for both plumes) and current/future construction
workers (inhalation) (3.1 for East Water Street Plume -Downgradient and 1.3 for Residential
Plume - Downgradient).
The tables below summarize the cancer risk and non-cancer hazards associated with exposure to
contaminated groundwater for the Residential and East Water Street Plume EAs. The tables show
only cancer risks greater 1 x 10"6 or non-cancer His greater than 1.
Table 5 - Summary of Groundwater Risks and Hazards in Upgradient Exposure Areas
Exposure
Area
Receptor
Calculated
Cancer
Risks
Calculated
Non-Cancer
Hazards (HI)
Risk
Drivers
Exposure Route
Residential
Plume
Upgradient
Future Resident
2.0 x 10"4
39
TCE/PCE
Ingestion of and dermal
contact with groundwater
used as a source of potable
water and inhalation of
vapors released from
potable use activities
(showering and washing
dishes and clothes.)
Current
Industrial/C ommercial
Worker
6.2 x 10"6
1.5
Inhalation of vapors
released from potable use
activities (washing dishes.)
Future
Industrial/C ommercial
Worker
3.8 x 10"5
8.8
Inhalation of vapors
released from potable use
activities (washing dishes.)
Current/Future
Construction Worker
7.5 x 10"7
20
Inhalation of vapors that
migrate from groundwater
into trench air.
Current/Future Utility
Worker
5.7 x 10"6
1.5
Inhalation of vapors that
migrate from groundwater
into trench air.
21
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East Water
Street
Plume
Upgradient
Future Residents
1.4 x 10"4
6.8
TCE/PCE
Ingestion of and dermal
contact with groundwater
used as a source of potable
water and inhalation of
vapors released from
potable use activities
(showering and washing
dishes and clothes.)
Future
Industrial/C ommercial
Worker
3.1 xlO"5
1.5
TCE
Inhalation of vapors
released from potable use
activities (washing dishes.)
Current/Future
Construction Worker
3.4 xlO"6
7.5
TCE
Inhalation of vapors that
migrate from groundwater
into trench air.
Table 6 - Summary of Groundwater Risks and Hazards in Downgradient Exposure Areas
Exposure
Area
Receptor
Calculated
Cancer
Risks
Calculated
Non-Cancer
Hazards
(HI)
Risk
Drivers
Exposure Route
Residential
Plume
Downgradient
Future Resident
1.3 x 10"5
1.4
PCE
Ingestion of and dermal
contact with groundwater
used as a source of potable
water and via inhalation of
vapors released from
potable use activities
(showering and washing
dishes and clothes.
Current/Future
Construction
Worker
1.5 x 10"7
1.3
Inhalation of vapors that
migrate from groundwater
into trench air.
East Water
Street Plume
Downgradient
Future Resident
1.1 x 10"5
1.4
TCE/PCE
Ingestion of and dermal
contact with groundwater
used as a source of potable
water and via inhalation of
vapors released from
potable use activities
(showering and washing
dishes and clothes.
Current/Future
Construction
Worker
9.8 x 10"8
3.1
Inhalation of vapors that
migrate from groundwater
into trench air.
Although the BHHRA indicates unacceptable risks via ingestion of on-Site groundwater for
hypothetical future residents in both upgradient plume exposure areas, all existing residents
within the ETC A Site are connected to municipal water and a local ordinance prohibits the
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construction of, and potable use of water from, private wells. Therefore, there are no current
unacceptable risks associated with ingestion of groundwater.
Vapor Intrusion
Other potential human exposure pathways identified in the BHHRA that pose an unacceptable
risk at the Site include inhalation of contaminant-containing vapors in indoor air based on sub-
surface vapor sampling. Vapors of contaminants found in subsurface soils and groundwater may
migrate into a structure's indoor air, a process referred to as "vapor intrusion." The BHHRA
indicates that for current and hypothetical future residents in the Residential Plume, the vapor
intrusion predicted cancer risks exceed 1 x 10"5 and a non-cancer HI risk greater than 1, as shown
in the table below. The limited record of indoor air monitoring of homes during the RI indicates
indoor air cancer risks are within the EPA acceptable risk range, even though some sub-surface
soil gas vapor concentrations were elevated above screening levels. Overall, there were no
compounds detected in the indoor air of homes at concentrations that present an unacceptable
health risk.
Table 7 - Summary of Vapor Intrusion Risks and Hazards in Upgradient Exposure Areas
Exposure Area
Exposure Scenario
Cumulative
Cancer Risk
Non-Cancer
Hazard Index (HI)
Residential Plume
Upgradient *
Current/Future Residents
2.7 xlO"5
6.1
East Water Street Plume
Upgradient **
Current/Future Residents
1.2 xlO"6
HI <1
* Based on actual sub-slab vapor sampling
** No indoor air or sub-slab vapor samples collected at Spinnaker or Hobart. Risk analysis is based on
sub-slab vapor samples collected from residential areas within the East Water Street Plume upgradient
exposure area.
In summary, there are a total of two soil and groundwater COCs (PCE and TCE) that represent a
potential risk greater than or equal to 1 x 10"6 or a hazard index greater than 1. However, as
discussed in the risk assessment summary above, risks are primarily driven by TCE in subsurface
soil.
2.7.2 Summary of Ecological Risk Assessment
A Screening-Level Ecological Risk Assessment (SLERA) was conducted for the Site during the
2015 RI to evaluate the current and potential future ecological risks associated with exposure to
Site-related contaminants via groundwater discharges, primarily to surface water and sediment in
the GMR. The only potential terrestrial ecological habitat is near the GMR, along the eastern
edge of the Site. However, there is no evidence that groundwater discharges directly to the
terrestrial habitat and, therefore, this habitat was not evaluated in the SLERA. Based on the
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results of the SLERA, EPA concluded aquatic receptors exposed to GMR surface water and
sediments are not at risk for adverse effects from ETC A Site contaminants in groundwater
discharges at this time.
2.7.3 Basis for Taking Action
The response action selected in this Interim ROD is necessary to protect the public health or
welfare or the environment from the actual or threatened releases of hazardous substances to the
environment. The interim action is intended to achieve a significant reduction (70 to 90 percent
reduction) of contaminant mass at the Residential Plume source area and reduction of COC
concentrations in groundwater downgradient of the source area. The interim action is also
intended to reduce or eliminate the risk posed by inhalation of TCE vapors from subsurface soils
and prevent the potential for human exposure to COCs during in-situ treatment via the vapor
intrusion pathway while a final remedial solution for the ETCA Site groundwater is developed.
2.8 Interim Remedial Action Objectives
Remedial action objectives (RAOs) provide a general description of what the cleanup will
accomplish, and typically serve as the design basis for the remedial alternatives which will be
presented in the following section. RAOs for the Site were developed based on COCs,
pathways, receptors, and an acceptable constituent level (RBC, PRO, chemical-specific ARAR,
or to-be considered criteria) for each medium assuming future residential use of the Site.
The following Interim RAOs for soil, groundwater, and vapor intrusion have been identified for
the two areas of the ETCA Site based on the summary of receptor risks and hazards for the
exposure scenarios presented in the BHHRA.
2.8.1 East Water Street Soil RAOs
EPA identified unacceptable risks or hazards in East Water Street exposure areas EA-1 and EA-6
for certain exposure scenarios. As such, the following RAOs have been developed to address
soil under this interim remedial action:
• Prevent exposure to TCE in soil that poses unacceptable non-cancer hazards to future
residents and future industrial/commercial workers in EA-1 (Hobart), and to future
residents in EA-6 (western part of Spinnaker parking lot).
• Minimize leaching of TCE and PCE from soil to groundwater in the EAs where
unacceptable non-cancer hazards exist (EA-1 and EA-6).
The interim remedial action will address hazards associated with exposure to contaminated soils
and be protective of groundwater. This will be achieved by reducing the concentrations of soil
contaminants to the RALs in Table 8 below.
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Table 8 - Soil Remedial Action Levels
(¦()(¦
Remedial Action Level
Trichloi'oelheiie (TCE)
34 |ag/ kg
Tetrachloroethane (PCE)
44 (ig/kg
Note:
a. Protection of Groundwater PRGs were derived using leaching equations in EPA Soil Screening
Guidance (EPA 1996b); with a combination of Site-specific input parameters and default values specified by Ohio
EPA. The lower of the calculated values (the values based on protection of groundwater) were selected as the RAL.
2.8.2 Residential Plume Source Area RAOs
The goal of the interim remedial action is to reduce the dissolved-phase contaminant mass at the
source of the Residential Plume and in the downgradient part of the plume where chlorinated
VOC concentrations are highest. Reduction of VOC mass at the source area and in the
downgradient dissolved phase plume may also facilitate an expanded range of remedial
alternatives for consideration for the final Site-wide groundwater remedy. It is also anticipated
that removing as much contaminant mass as possible will improve the effectiveness and
efficiency of the final Site-wide groundwater remedy.
Achieving final Site groundwater cleanup levels (i.e., SDWA MCLs) is not a goal of this interim
remedial action. A remedial action to reach the final cleanup goals for groundwater will be
selected at a later date as part of a future final Site-wide groundwater remedy. As such, the
following RAOs have been developed to address the groundwater source area under this interim
remedial action:
• Achieve a 70 to 90 percent reduction in dissolved total VOC mass in groundwater in the
area designated as treatment Zone A; and
• Achieve a 70 to 90 percent reduction in dissolved total VOC mass in groundwater
throughout the entire targeted treatment area (Zone A through Zone D).
For the purposes of this interim action, groundwater RAOs based on 70 to 90 percent dissolved
phase mass reduction were established for four "treatment" zones (Zones A through D). See
Figure 13 for location of the targeted treatment zones. Zone A includes the source area (assumed
to be at least partially covered by the 2002 church addition) with the highest groundwater
contaminant concentrations and the immediate downgradient dissolved phase plume extending to
Mulberry Street. Zones B, C, and D, where contamination has migrated from Zone A, are
downgradient between Mulberry and Clay Streets, Clay and Crawford Streets, and Crawford and
Union Streets, respectively.
Maximum VOC concentrations in Zones B, C, and D gradually decrease from upgradient to
downgradient from approximately 800 |ig/L at Clay Street to 400 |ig/L at Union Street. Residual
dissolved-phase contamination at such concentrations may continue to contribute PCE to the
plume.
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Zones A, B, C and D cover a predominantly residential area and comprise most of the
"upgradient" exposure area of the Residential Plume, where the calculated VI risk is the highest.
For these reasons, the interim remedial action will actively target groundwater contamination in
Zones B, C, and D along with the source area in Zone A.
Achieving a 70 percent reduction in dissolved phase VOC mass (based on confirmatory
sampling or performance monitoring wells) in treatment Zone A would be indicative that VOC
concentrations in the source area have been reduced to less than 1,500 |ig/L PCE, or less than 1
percent of the solubility limit of PCE. This will provide confidence that no DNAPL remains in
the source area after treatment. Although DNAPL has not been observed in groundwater
samples collected at the Site to date, its presence is conservatively assumed based on EPA
studies of other sites involving chlorinated VOCs. Removing 70 to 90 percent of the
contaminant mass will also substantially deplete the amount of PCE available in Zone A to feed
the downgradient portions of the plume in Zones B through D. Groundwater VOC
concentrations throughout Zones B through D would then be reduced to a range of less than 100
|ig/L in Zone D to about 150 |ig/L in Zone B, which will in turn reduce the potential for VI at the
Site.
2.8.3 Vapor Intrusion RAOs
The interim remedy for the ETC A Site has the following RAO regarding VI at the Site:
• Mitigate the potential for vapor intrusion into buildings overlying the targeted
groundwater treatment area plus an additional buffer area extending three blocks beyond
the downgradient end of the targeted treatment area to Frank Street.
Although no unacceptable VI risks to public health were documented during the RI based on
direct measurements of indoor air samples collected at a limited number of homes/business that
granted EPA access, EPA guidance allows for preemptive VI mitigation if sub-slab vapor
concentrations are elevated and indicate a potential for future unacceptable risk. The interim
action VI RAO will preemptively mitigate unacceptable VI exposures within the targeted
treatment area (Zones A through D plus the buffer) and will not involve evaluating new vapor
data to determine the area of action. The RALs for VI are solely to document acceptable
performance of the vapor mitigation systems following installation and to make adjustments if
necessary. The RALs for indoor air are in Table 9 below.
Table 9 - Vapor Intrusion Remedial Action Levels
(¦()(¦
Residential Remedial
Action Level
(MS 1,1')
Commercial/
Industrial Remedial
Action Level (ug in')
Trichloroethene (TCE)
2.1
8.8
Tetrachloroethene (PCE)
42
180
Hg/m3 - microgram per cubic meter of air
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2.9 Description of Interim Alternatives
EPA developed and evaluated the following cleanup alternatives for addressing the current and
potential risks to human health or the environment.
2.9.1 Interim Soil Alternatives
Three remedial alternatives were developed for the East Water Street soil source areas.
2.9.1.1 Alternative S-l: No Action
Estimated Capital Cost: $0
Estimated Total O&M Cost: $0
Estimated Present Worth Cost: $0
Estimated Construction Timeframe: None
The "No Action" alternative is required under CERCLA, and it serves as a baseline comparison
with other alternatives. This alternative entails no remedial action at the Site. No costs were
assumed for this alternative.
2.9.1.2 Alternative S-2: Excavation of Impacted Soil at Hobart EA-1 and
Spinnaker EA-6 with Off-Site Disposal
Estimated Capital Cost: $1,762,724
Estimated Total O&M Cost: $0
Estimated Present Worth Cost: $2,290,000
Estimated Construction Timeframe: 3 months
Estimated Time to Achieve RAOs: 3 months
This alternative includes excavation and off-Site disposal of contaminated soil at Hobart EA-1
and Spinnaker EA-6. Assuming Hobart EA-1 soils are excavated to a depth of 15 feet bgs, the
estimated volume of soils removed is 9,110 cubic yards. Assuming Spinnaker EA-6 soils are
excavated to a depth of 6 feet bgs, the estimated volume of soils removed is 753 cubic yards.
The proposed depth of the excavation correlates to the depth of contamination detected in soil
during RI sampling. The excavated soil will be from the vadose zone (not saturated) and thus is
not anticipated to require dewatering. Excavated soils will therefore be directly loaded into dump
trucks and transported to an off-Site licensed landfill for disposal. The excavation activities
would take about 3 months to complete. See Figure 14 for proposed excavation areas under Soil
Alternative S-2.
Post-excavation sampling would be conducted to confirm that impacted subsurface soil was
removed during excavation and that cleanup goals were met. Excavated areas would then be
backfilled with gravel or clean soil. Because excavation will remove the contaminated soils to a
concentration that EPA considers protective for unrestricted use and unlimited exposure (under
the residential scenario) from the targeted areas on the Hobart and Spinnaker properties, no long-
term operations and maintenance or institutional controls will be needed for the excavated areas.
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Although EA-1 is currently occupied by Hobart and EA-6 is used by Spinnaker as an asphalt-
paved parking lot, in the future, these areas could be developed for residential use. For this
alternative, EPA assumes that 10 percent of the excavated soils will be managed as hazardous
waste.
ARARs for this alternative include the State of Ohio standards for the excavation, transportation,
and off-Site disposal of hazardous waste under the Ohio Administrative Code (O.A.C.) Chapters
3745-50 through 57, 65 through 69, 205, 266, 270, 273 and 279. Excavation work would also
comply with State of Ohio standards under O.A.C. Chapters 3745-17-08, which deals with
fugitive dust emissions.
EPA would not need to conduct five-year reviews (FYRs) at EA-1 and EA-6 with selection of
this alternative because contaminated soil would be permanently removed and disposed of off-
Site. The estimated total cost of Alternative RGW-2A is $2,290,000.
2.9.1.3 Alternative S-3: Excavation With Off-Site Disposal for Hobart EA-1
Soils and Asphalt Cap with Institutional Controls at Spinnaker EA-6
Estimated Capital Cost: $1,642,949
Estimated Total O&M Cost: $14,500
Estimated Present Worth Cost: $2,470,000
Estimated Construction Timeframe: 9 months
Estimated Time to Achieve RAOs: 9 months
This alternative combines excavation and off-Site disposal of contaminated soils at Hobart EA-1
with the installation of an asphalt cap at Spinnaker EA-6. See Figure 15 for proposed soil
excavation and asphalt cap areas under Soil Alternative S-3. Although contaminated EA-6 soil
is currently under asphalt pavement, the existing asphalt pavement is not constructed in
accordance with the State of Ohio's guidance for caps. The area to be capped at Spinnaker EA-6
is approximately 3,175 square feet. The asphalt cap would require the excavation of
approximately 14 inches of material (the existing 2-inch pavement plus 12 inches of
contaminated soil) for an estimated 137 cubic yards of material for off-Site disposal.
Following removal of the top 14-inch layer on the Spinnaker EA-6 area, a new base course layer
would be installed to an 8-inch depth. A 6-inch thick layer of asphalt would then be installed
over the base course layer and would be sloped toward the existing storm sewers at the
Spinnaker property. Since contaminated soils will remain on the property below the asphalt cap,
institutional controls would be required to prevent residential use in the Spinnaker EA-6 area and
to ensure the asphalt cap is maintained and remains in place. Operations and maintenance
include annual inspection of the asphalt for cracks and potholes.
ARARs for this alternative include the State of Ohio standards for the excavation, transportation,
and off-Site disposal of hazardous waste under O.A.C. Chapters 3745-50 through 57, 65 through
69, 205, 266, 270, 273 and 279. Excavation work would also comply with State of Ohio
standards under O.A.C. Chapters 3745-17-08, which deals with fugitive dust emissions. The
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ARAR-compliant asphalt cap would be designed and constructed in accordance with Ohio EPA
guidance and regulations.
EPA would need to conduct a FYR every five years to ensure the integrity of the asphalt cap at
EA-6 in perpetuity. The estimated total cost of Alternative RGW-2A is $2,470,000.
2.9.2 Interim Groundwater Alternatives
Remedial alternatives for the Residential Plume source area and downgradient groundwater (or
the "targeted treatment area" starting about V2 block northwest of Walnut to Union Street) for
the ETC A Site are presented below. All groundwater alternatives are numbered to correspond
with the numbers in the FFS Report. "RGW" is an acronym for groundwater below the
residential portion of the Site within the targeted treatment area. The targeted treatment area
(Zones A-D) is shown in Figure 13. Overall, two general remedial alternatives were developed
to address groundwater at the ETCA Site. The two alternatives are Alternative RGW-1, the "No
Action" alternative, and Alternative RGW-2, In-situ Groundwater Treatment and Groundwater
Monitoring.
2.9.2.1 Alternative RGW-1: No Action
Estimated Capital Cost: $0
Estimated Total O&M Cost: $0
Estimated Present Worth Cost: $0
Estimated Construction Timeframe: None
The "No Action" alternative is required under CERCLA, and it serves as a baseline comparison
with other alternatives. This alternative entails no remedial action at the Site. No costs were
assumed for this alternative.
2.9.2.2 Alternative RGW-2: In-Situ Groundwater Treatment and
Groundwater Monitoring
Groundwater Alternative RGW-2 is comprised of three potential in-situ treatment options:
Enhanced Reductive Dechlorination or "ERD" (Alternative RGW-2A); In-Situ Chemical
Reduction or "ISCR" (Alternative RGW-2B); and In-Situ Chemical Oxidation or "ISCO"
(Alternative RGW-2C), as discussed below.
The goal of this groundwater interim action (in-situ treatment) is to reduce contaminant mass
within the targeted treatment area, which includes the Residential Plume source area and
groundwater downgradient of the original source area (to Union Street). This interim action is
not intended to restore the aquifer to SDWA MCLs. As discussed above, the final cleanup levels
for groundwater will be addressed as part of a future final Site-wide groundwater remedy.
Reducing contaminant mass in the source area will reduce the amount of dissolved-phase
contamination migrating downgradient from the source area and will reduce concentrations of
chlorinated VOCs throughout Zones A through D. Contaminated groundwater outside the
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targeted treatment area (downgradient from Union Street) will not be treated as part of this
interim action but will be addressed in the final Site-wide groundwater remedy. However, the
reduction of PCE concentrations in Zones A-D during the interim action should result in lower
contaminant concentrations downgradient in the interim by reducing the amount of PCE that is
available to feed the plume and migrate further downgradient.
Site-wide groundwater monitoring will be conducted in the Residential Plume to evaluate the
effectiveness of the interim action in reducing overall source area mass and contaminant
concentrations in the dissolved phase plume. Monitoring will also be conducted for methane and
potential daughter products of PCE as it breaks down from treatment.
The City of Troy has ordinances governing the use of private wells that will continue to prevent
exposure to contaminated groundwater while the interim action is being implemented. In
addition, the risk of impact to the City's East Well Field would also be minimized by sequencing
remedy treatment applications (injections) gradationally to evaluate the aquifer's response,
beginning in treatment Zone A located furthest from the well field. Sentinel wells will provide
advance warning of conditions requiring correction such as daughter products produced, metals
in groundwater mobilized, etc. Sequencing the remedy injections will provide an added level of
control to minimize the risk of adversely affecting the East Well Field. Long-term groundwater
monitoring would track remedial performance, as well as provide information that could
optimize the remedy. Treatment parameters could then be adjusted, if needed, as treatment is
initiated in Zones B, C and D.
Common elements shared by all groundwater alternatives are discussed below followed by a
more detailed description of each of the proposed groundwater alternatives, RGW-2A, 2B, and
2C. See Figure 16 for a conceptual layout of Alternatives RGW-2A, 2B, and 2C.
Common Elements of Groundwater Alternatives RGW-2A, 2B, and 2C:
• All Groundwater Alternatives RGW-2A, 2B, and 2C will treat the most contaminated
portions of the Residential Plume via in-situ treatment. This includes in-situ treatment of
the Residential Plume source area (former dry cleaner location -present day church
addition area along Walnut Street where the bulk of the VOC mass is located) and
groundwater downgradient of the source area (from Walnut to Union Street).
Groundwater in this four-block area (referred to as the "targeted treatment area") includes
those areas of the Residential Plume where total chlorinated VOC concentrations are
greater than 500 ug/L, with the highest total chlorinated VOCs detected near the source
area along Walnut Street at a concentration of 3,560 ppb.
• All Groundwater Alternatives RGW-2A, 2B and 2C assume that treatment of
groundwater beneath a portion of the current church addition structure will be required.
This will likely require the injection of treatment amendments into the groundwater
aquifer upgradient of the church. Additional data will be collected during the pre-design
studies to determine the exact injection locations and depths.
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• In-situ treatment between Walnut Street and Clay Street (Zones A and B) would target
groundwater from a vertical interval of approximately 17 feet to 100 feet bgs. East of
Clay Street in Zones C and D, in-situ treatment would target a vertical interval of
approximately 15 feet to 50 feet bgs. Actual treatment locations and depths will be
confirmed during predesign studies to support the Remedial Design.
• Groundwater will be treated sequentially starting in Zone A (source area and groundwater
immediately downgradient of source to Mulberry Street) then progress downgradient
through Zones B through D (dissolved phase plume from Mulberry Street to Union
Street). Sequenced treatment starting in Zone A will allow for monitoring of factors such
as reduction of VOCs, formation of daughter products, and/or mobilization of metals.
This monitoring will allow for the adjustment of treatment parameters as needed before
moving to subsequent Zones B, C, and D. Sequencing treatment would also minimize
the risk of impact to the city's East Well Field.
• Active remediation (in-situ injections) would continue until the average dissolved-phase
contaminant mass, as determined through collection of groundwater samples over time,
in treatment Zone A, and the total amount in Zones A through D, has been reduced by 70
to 90 percent without evidence of rebound.
Groundwater Alternatives RGW-2A, 2B, and 2C are discussed in detail below.
2.9.2.2.1 Alternative RGW-2A: In-Situ Groundwater Treatment Using
Enhanced Reductive Dechlorination (ERD)
Estimated Capital Cost: $10,943,795
Estimated Total O&M Cost: $ 3,493,592
Estimated Present Worth Cost: $18,769,000
Estimated Construction Timeframe: 1 year
Estimated Timeframe to Achieve RAOs: 15 years
Alternative RGW-2A consists of in-situ biological treatment of the Residential Plume source
area and downgradient groundwater using ERD. ERD would involve biostimulation and
bioaugmentation of the aquifer. Bioaugmentation would speed the complete dechlorination of
PCE to ethene and reduce the production of vinyl chloride (VC), a volatile daughter product of
PCE which is more toxic than PCE and TCE. Depending on the method of injection,
biostimulation may employ generic substrates, such as sodium lactate, or proprietary time-
release substrates such as emulsified vegetable oils. Bioaugmentation would also require
proprietary Dehaloccoides microorganism cultures.
Alternative RGW-2A may potentially generate methane as the treatment of VOCs progresses.
Methane generation is not expected to be significant and can be controlled using inhibitors, if
necessary. ERD also has the potential to generate minor amounts of intermediate byproducts of
PCE and TCE, including TCE, cDCE, and VC, which could present a VI risk to residents above
the groundwater plume within the targeted treatment area. However, VI risks to residents would
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be minimized by installing SSDs in all structures above the targeted treatment area plus a buffer
zone (Walnut to Frank Streets).
Alternative RGW-2A relies on recirculation to distribute the treatment amendments (ERD
chemicals) throughout Zones B, C and D. Where recirculation is used, groundwater would be
extracted downgradient of the targeted treatment zone, conveyed to process equipment where
remediation (ERD) chemicals would be added, and most of it would then be reinjected
upgradient of the targeted treatment area. Therefore, a clean source of water to mix with the
treatments amendments is not required for Zones B, C, and D, as this water would be supplied by
extraction wells from the downgradient ends of these treatment zones and recirculated. For Zone
A, a new water supply well will be needed.
For treatment in Zone A, clean groundwater would be pumped from a new water supply well
(located outside the plume) and conveyed to process equipment where ERD treatment
amendments would be added. This amended groundwater would then be injected into the clean
aquifer upgradient of the church (about V2 block south of Market Street). This treated
groundwater would then flow underneath the church and react with the residual source material,
where PCE concentrations as high as 3,560 |ig/L exist along Walnut Street. Since contaminated
groundwater exiting Zone A cannot be reinjected (or recirculated) into clean areas outside the
plume (upgradient of church), groundwater exiting Zone A will be extracted and treated ex-situ
via air stripping prior to being discharged to the city's publicly-owned treatment works (POTW).
See Figure 17 for an Alternative RGW-2A conceptual layout.
Alternative RGW-2A requires injection wells, extraction wells, and piping connecting these
wells to central process equipment. Injection and/or extraction locations would be located
upgradient from the source area (on the Market and East Main Streets sides of Zone A) as well as
on the Walnut Street side of the source area. Targeting contamination over extended vertical
intervals within treatment areas would require nested injection wells screened at multiple depths.
Predesign studies will be conducted to determine the injection locations and depths of nested
injection wells.
It would take one year to distribute ERD chemicals completely within each treatment zone. The
recirculation system would operate for one year in each zone to distribute the chemicals and then
shut down for two years to allow the ERD breakdown processes to continue. ERD injections
would be performed at least twice in each treatment zone. Remediation goals for Zones A
through D are expected to be achieved within 15 years of commencement of groundwater
remediation.
ARARs for this alternative include the federal Underground Injection Control (UIC) regulations,
40 C.F.R. Parts 144 to 147 for subsurface injection work and recirculation of contaminated
groundwater. Subsurface injection work and recirculation of contaminated groundwater would
also need to comply with the substantive Ohio provisions under O. A C. 3745-34-06 through
3745-34-09. The management of extracted groundwater from Zone A, via discharge to the local
POTW, would also need to comply with O.A.C. 3745-3-04, Paragraphs A-D. Other ARARs
pertain to emissions from air pollution control equipment (emissions from air strippers) under
O.A.C 3745-21-09.
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EPA would need to conduct a FYR every five years until RAOs are reached without evidence of
rebound. The estimated total cost of Alternative RGW-2A is $18,769,000.
2.9.2.2.2 Alternative RGW-2B: In-Situ Groundwater Treatment Using
Chemical Reduction (ISCR)
Estimated Capital Cost: $ 16,179,797
Estimated Total O&M Cost: $3,097,418
Estimated Present Worth Cost: $25,061,000
Estimated Construction Timeframe: 1 year
Estimated Timeframe to Achieve RAOs: 10 years
Alternative RGW-2B consists of in-situ chemical (reduction) treatment of Residential Plume
source area and downgradient groundwater using ISCR. Similar to RGW-2A, this alternative
relies on recirculation to distribute the amendments throughout treatment Zones B through D and
requires the treatment of groundwater extracted from Zone A prior to its discharge to the city's
POTW. See Figure 17 for an Alternative RGW-2B Conceptual Layout.
Alternative RGW-2B may also potentially generate methane as the treatment of VOCs
progresses, but it can be controlled using inhibitors, if necessary. ISCR may solubilize naturally-
occurring arsenic and manganese in treatment areas and cause them to migrate downgradient.
However, dissolved arsenic and manganese are expected to return to their original insoluble
forms when they migrate beyond the artificially induced reduction zones within the treatment
areas.
It would take approximately one year to completely distribute ISCR chemicals within each
treatment zone. ISCR injections would be performed at least twice in each treatment zone.
Remediation goals for Zones A through D are expected to be achieved within 10 years of
commencement of groundwater remediation.
ARARs for this alternative include the federal UIC regulations, 40 C.F.R. Parts 144 to 147 for
subsurface injection work and recirculation of contaminated groundwater. Subsurface injection
work and recirculation of contaminated groundwater would also need to comply with the
substantive Ohio provisions under O.A.C. 3745-34-06 through 3745-34-09. The management of
extracted groundwater from Zone A, via discharge to the local POTW, would also need to
comply with O.A.C. 3745-3-04, Paragraphs A-D. Other ARARs pertain to emissions from air
pollution control equipment (emissions from air strippers) under O.A.C 3745-21-09.
EPA would conduct a FYR every five years until RAOs are reached without evidence of
rebound. The estimated cost of Alternative RGW-2B is $25,061,000.
2.9.2.2.3 Alternative RGW-2C: In-Situ Groundwater Treatment Using
Chemical Oxidation (ISCO)
Estimated Capital Cost: $6,911,454
Estimated Total O&M Cost: $2,293,409
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Estimated Present Worth Cost: $11,966,000
Estimated Construction Timeframe: 1 year
Estimated Timeframe to Achieve RAOs: 10 years
Alternative RGW-2C consists of in-situ chemical treatment of the Residential Plume source area
and downgradient groundwater using ISCO. See Figure 18 for an Alternative RGW-2C
Conceptual Layout.
Unlike Alternatives RGW-2A and 2B, Alternative RGW-2C does not require recirculation to
distribute the treatment amendments throughout the treatment zones, eliminating the need to
comply with treatment and disposal requirements associated with recirculation and disposal to a
POTW. Clean groundwater would be pumped from a new water supply well (located outside the
plume), conveyed to process equipment where ISCO chemicals would be added, and then
directly injected into the aquifer along a series of injection wells throughout the treatment zones
(Zones A through D).
The ISCO treatment amendment would be either permanganate or persulfate. Alternative RGW-
2C would not produce byproducts of dechlorination (TCE, cDCE, and VC). Alternative RGW-
2C may solubilize naturally-occurring heavy metals during treatment by producing oxidizing
conditions within the treatment zones. These oxidizing conditions may cause chromium to
temporarily transition from insoluble trivalent chromium (Cr-III) to soluble hexavalent
chromium (CR-VI), which is more toxic. However, CR-VI is expected to return to its insoluble
form once it migrates beyond the artificially induced oxidizing zones within the treatment areas.
ISCO injections would be performed continuously via permanent wells. At the assumed seepage
rate of one foot/day, it is anticipated that the injectate would reach the downgradient end of each
treatment zone within approximately 6 to 12 months from the start of injection at the upgradient
end of that particular zone. Remediation goals for Zones A through D are expected to be
achieved within 10 years of commencement of groundwater remediation.
ARARs for this alternative include the federal UIC regulations 40 C.F.R. Parts 144 to 147 for
subsurface injection work. This on-Site interim remedy alternative providing for subsurface
injection would also be subject to the substantive provisions of O.A.C. 3745-34-06 through
3745-34-09.
EPA would need to conduct a FYR every five years until RAOs are reached without evidence of
rebound. The estimated cost of Alternative RGW-2C is $11,966,000.
2.9.3 Interim Soil Vapor Intrusion Alternatives
As part of this interim action, EPA is offering to install Sub-slab Depressurization Systems
(SSDs) at all buildings located above the targeted treatment area (Walnut to Union Street) and
within an additional "buffer" area extending three blocks downgradient of the treatment area to
Frank Street. See Figure 19 for the proposed vapor mitigation area.
Although no unacceptable risks to public health were evident based on direct measurements of
indoor air samples collected during the RI, EPA guidance allows for preemptive VI mitigation if
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sub-slab vapor concentrations are high and may pose a potential for future unacceptable risk.
Additionally, it is also possible that some groundwater remediation alternatives can generate
minor amounts of degradation products from PCE, such as TCE, c-DCE or VC in the short term.
For these reasons, EPA is including preemptive VI mitigation of all buildings above the targeted
treatment area and in the buffer area (Walnut to Frank Street) as part of this interim action.
Installing SSDs would also be less costly and less intrusive to the homeowners than conducting
long-term vapor intrusion monitoring (collecting sub slab vapor and indoor air samples
(seasonally) at each home within the VI mitigation area) during the course of the interim action.
Two soil vapor alternatives were evaluated for this interim action as follows:
2.9.3.1 Alternative VI-1: No Action
Estimated Capital Cost: $0
Estimated Total O&M Cost: $0
Estimated Present Worth Cost: $0
Estimated Construction Timeframe: None
The "No Action" alternative is required under CERCLA, and it serves as a baseline comparison
with other alternatives. This alternative entails no remedial action at the Site. No costs were
assumed for this alternative.
2.9.3.2 Alternative VI-2: Residential Plume Sub-Slab Depressurization
Systems (SSDsj and Performance Monitoring
Estimated Capital Cost: $1,281,946
Estimated Total O&M Cost: $2,846,654 (for 15 years)
Estimated Present Worth Cost: $5,367,180
Estimated Construction Timeframe: 6 days/home; total of 23 weeks
Under Alternative VI-2, EPA would install SSDs at approximately 156 properties (28
commercial and 128 single-family homes) above the targeted groundwater treatment area plus a
two-block buffer (Walnut to Frank Street) to actively remove soil vapors from beneath the
building's slab to reduce the potential for unacceptable VI during treatment of groundwater
under this interim action.
SSDs employ extraction points in a basement floor connected to a high-static pressure fan. The
extraction point(s) typically consist of 3-inch diameter PVC pipe that is cored in the sub slab
(underneath building) and sealed. The PVC piping is routed outside the building from the
extraction point, where the high-pressure fan is located. The fan is typically attached to the side
of the building and exhaust is vented through PVC piping above the roof line, so none of the
exhaust will reenter the building through windows or vents.
For buildings with dirt basement floors, special design considerations would be required, such as
installation of a plastic membrane liner to ensure proper functioning of the SSDs. Based on
inspections conducted during the RI, approximately eight percent of buildings may have dirt
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basement floors; therefore, it is assumed that 9 of the 110 total buildings tested (during the RI
and the EPA Removal Action) will require plastic membrane liners. Indoor air monitoring
would be required and post-installation follow-up (performance monitoring) testing would be
done to ensure the SSDs are functioning properly.
The estimated cost of Alternative VI-2 is $5,367,180.
2.10 Summary of Comparative Analysis of Alternatives
According to the NCP, nine criteria are used to evaluate the different remediation alternatives
individually and against each other in order to select a remedy. The nine criteria can be
subdivided into three categories: threshold criteria, primary balancing criteria, and modifying
criteria. The threshold criteria are (1) overall protection of human health and the environment
and (2) compliance with Applicable or Relevant and Appropriate Requirements (ARARs) of
environmental laws. These threshold criteria must be met in order for a remedial alternative to
be eligible for selection. The primary balancing criteria are long-term effectiveness and
permanence; reduction of toxicity, mobility, or volume through treatment; short-term
effectiveness; implementability; and cost. These are the technical criteria used as the basis for
the detailed analysis. The modifying criteria (State and community acceptance) are assessed
formally after the public comment period.
Soil Vapor Alternative VI-2 is not discussed below because EPA guidance states that a
comparative evaluation, against the nine NCP criteria, is not necessary when only one active
alternative exists and the other is the "no action" alternative. A more detailed analysis of each of
the interim remedial alternatives can be found in the FFS.
Threshold Criteria
1. Overall Protection of Human Health and the Environment determines whether an
alternative eliminates, reduces, or controls threats to public health and the environment
through institutional controls, engineering controls, or treatment.
2. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)
evaluates whether the alternative meets Federal and State environmental statutes,
regulations, and other requirements that pertain to the Site, or whether a waiver is
justified.
Primary Balancing Criteria
3. Long-term Effectiveness and Permanence considers the ability of an alternative to
maintain protection of human health and the environment over time.
4. Reduction of Toxicity, Mobility, or Volume Through Treatment evaluates an
alternative's use of treatment to reduce harmful effects of principal contaminants, their
ability to move in the environment, and the amount of contamination present.
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5. Short-term Effectiveness considers the length of time needed to implement an
alternative and the risks the alternative poses to workers, residents, and the environment
during implementation.
6. Implementability considers the technical and administrative feasibility of implementing
the alternative, including factors such as the relative availability of goods and services.
7. Cost includes estimated capital and annual operations and maintenance costs, as well as
present worth cost. Present worth costs are the total costs of an alternative over time in
terms of today's dollar value. Cost estimates are expected to be accurate within a range
of+50 to -30 percent.
Modifying Criteria
8. State/Support Agency Acceptance considers whether the State agrees with the EPA's
analysis and recommendation, as described in the RI/FS and Proposed Plan.
9. Community Acceptance considers whether the local community agrees with EPA's
analysis and preferred alternative. Comments received on the Proposed Plan are an
important indicator of community acceptance.
2.10.1 Overall Protection of Human Health
Soil Alternative S-l and Groundwater Alternative RGW-1 (no action) would provide no risk
reduction and would not be protective of human health or the environment. Because
Alternatives S-l and RGW-1 do not pass this threshold criterion, they were not considered for
selection.
All soil remedial alternatives provide comparable overall protection of human health from
impacted soils. Alternative S-2 (excavation) would be the most protective because it would
permanently remove the contaminated soils in both EA-1 and EA-6, eliminating the potential
risk of future contact (via inhalation) with contaminants and the potential for contaminants to
leach to groundwater in the future. Alternative S-3 (excavation with off-Site disposal and
capping) would be slightly less protective, as it would leave contaminated soils in place at EA-6.
The low-permeability cap would prevent contact with contaminated soils and also limit (but not
eliminate) the potential for infiltration and leaching of contaminants from soil to groundwater.
Alternative S-3 would rely on institutional controls (ICs) to ensure continued maintenance and
the long-term integrity and performance of the cap. Contaminated soils under the cap could
potentially contact groundwater during periods of high subsurface water levels, thus some on-
going potential for leaching would remain even if the cap is maintained as designed.
All Groundwater Alternatives RGW-2A (ERD), RGW-2B (ISCR), and RGW-2C (ISCO) destroy
the same amount of VOC mass (more than 70 percent) in groundwater at the source area and
throughout the entire targeted treatment area through in-situ treatment.
Groundwater Alternative RGW-2C would be most protective for the Residential Plume, with
Alternatives RGW-2A and RGW-2B being slightly less protective. Alternatives RGW-2A,
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RGW-2B, and RGW-2C all rely on groundwater monitoring and contingency measures to
protect the City of Troy's East Well Field from unforeseen potential effects of source treatment.
However, Alternative RGW-2C is least likely to produce dechlorination byproducts (TCE,
cDCE, and VC) as PCE and TCE are reduced during treatment. Although all alternatives may
solubilize naturally-occurring metals, solubilized metals are not expected to migrate more than a
few hundred feet beyond the treatment area, which would be 1,000 feet upgradient of the East
Well Field. In all alternatives, existing City of Troy ordinances governing the use of private
potable water supply wells within the municipal water service area would continue to minimize
the risk of human exposure to contaminated groundwater.
2.10.2 Compliance with Applicable or Relevant and Appropriate Requirements
Soil Alternatives S-2 and S-3 would comply with Federal and State ARARs. Soils would be
remediated or capped to achieve the RAOs. Under these alternatives, it is assumed the majority
of excavated contaminated soil would be disposed of as nonhazardous waste and a portion would
be disposed of as hazardous waste. ARARs involving excavation, transportation, and disposal of
both non-hazardous and hazardous waste would apply. The cap for EA-6 will be designed in
accordance with State of Ohio ARARs for asphalt caps.
Groundwater Alternatives RGW-2A, RGW-2B and RGW-2C would comply with ARARs;
however, RGW-2A and RGW-2B would rely on recirculation to be effective and thus would
require reinjection of groundwater extracted from within the treatment areas. This would require
Ohio EPA approval for reinjection of extracted groundwater. For this reason, compliance with
ARARs would be most easily achieved by Alternative RGW-2C, which does not rely on
recirculation to distribute treatment amendments.
The primary ARARs for soil Alternatives S-2 and S-3 include the State of Ohio standards for the
excavation, transportation, and off-Site disposal of hazardous waste under O.A.C. Chapters
3745-50 through 57, 65 through 69, 205, 266, 270, 273 and 279. Excavation work would also
comply with State of Ohio standards under O.A.C. Chapters 3745-17-08, which deals with
fugitive dust emissions. The ARAR-compliant asphalt cap under Alterative S-3 would need to
be designed and constructed in accordance with Ohio EPA guidance and regulations.
The primary ARARs for all groundwater Alternatives RGW-2A, RGW-2B, and RGW-2C
include the federal UIC regulations, 40 C.F.R. Parts 144 to 147 for subsurface injection work and
recirculation of contaminated groundwater. Subsurface injection work and recirculation of
contaminated groundwater (Alternatives RGW-2A and RGW-2B) would also need to comply
with the substantive Ohio provisions under O.A.C. 3745-34-06 through 3745-34-09. For
Alternatives RGW-2A and RGW-2B, the management of extracted groundwater from Zone A,
via discharge to the local POTW, would also need to comply with O.A.C. 3745-3-04, Paragraphs
A-D. Other ARARs for these alternatives include emissions from air pollution control
equipment (emissions from air strippers) under O.A.C 3745-21-09.
2.10.3 Long-Term Effectiveness and Permanence
Soil Alternative S-2 would provide the highest degree of long-term effectiveness and
permanence for soils because impacted soils are excavated and disposed off-Site, thereby
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eliminating the potential risk from contact with contaminants and eliminating the possibility of
leaching of contaminants from soil to groundwater. Alternative S-3 (excavation and capping)
would also eliminate the direct contact pathway but would be less permanent and less effective
in the long-term. Although a cap at EA-6 would eliminate the potential for contact with
contaminated soils and reduce infiltration, Alternative S-3 would leave a potential source of
groundwater contamination in place at EA-6 and would rely on ICs to limit uses of the capped
area and ensure continued maintenance, integrity and performance of the cap.
All Groundwater Alternatives RGW-2A, RGW-2B, and RGW-2C would have similar
effectiveness because they would each attain RAOs and result in the same relative reduction of
residual risk by reducing the contaminant mass in groundwater. However, the effectiveness of
Alternative RGW-2C would be contingent on Natural Oxidant Demand (NOD) testing to
confirm that aquifer conditions are favorable. All alternatives would rely on long-term
groundwater monitoring to evaluate the effectiveness of each alternative.
2.10.4 Reduction of Toxicity, Mobility, or Volume through Treatment
Soil Alternatives S-2 and S-3 do not involve treatment and would therefore not achieve reduction
of toxicity, mobility, or volume through treatment, since soils will be excavated and disposed at
an off-Site licensed landfill and/or capped in place.
Because they would all treat source materials constituting principal threats, Groundwater
Alternatives RGW-2A, RGW-2B, and RGW-2C would all meet the statutory preference for the
selection of a remedy that involves treatment as a principal element. Groundwater Alternatives
RGW-2A, RGW-2B, and RGW-2C would all destroy approximately the same amount of total
dissolved VOC mass throughout the targeted treatment area (70 to 90 percent reduction). As in-
situ treatment progresses, the volume of contaminated groundwater would be reduced. However,
the mobility of COCs would not be affected.
2.10.5 Short-Term Effectiveness
Soil Alternatives S-2 and S-3 will address Site contaminants in a relatively short period of time,
although Alternative S-2 would be shorter. The time to implement and complete the remedial
action for Alternative S-2 is estimated at 3 months, while Alternative S-3 is 9 months. These
alternatives involve potential short-term risks that result from handling contaminated soil during
excavation, capping, and transportation. The short-term risks to workers include direct contact
and inhalation of hazardous substances in soil during excavation and transportation. Risks
during construction may include spilling contaminated wastes or fuel that will be stored on-Site,
environmental releases through wind or storm water erosion, dust generation, physical hazards
from heavy equipment, traffic disturbances from road or lane closures and noise. However, the
risks to the community and workers would be minimized by employing dust suppression during
excavation and dump truck loading, and dump trucks would be covered with tarps during
transport. Workers would also be protected from direct contact, inhalation, and physical hazards
using proper health and safety measures (protective clothing and respiratory equipment, as
needed) and the use of standard construction and safety practices.
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Groundwater Alternatives RGW-2A, RGW-2B, and RGW-2C would have similar types of
construction requirements. Alternative RGW-2C (which does not require recirculation) would
be slightly easier to construct and operate, and therefore more effective in the short term. All
alternatives would pose similar short-term risks until interim action goals are attained. RGW-2A
is expected to take 15 years or less to attain remediation goals, while Alternatives RGW-2B and
RGW-2C are estimated to take 10 years or less to achieve the goals. Therefore, Alternatives
RGW-2B and RGW-2C would have similar short-term effectiveness with respect to the duration
and risk of exposure to contaminated groundwater until RAOs are achieved, and Alternative
RGW-2A would be slightly less effective. Regarding the complexity of construction and risk of
exposure during remediation, Alternative RGW-2C would be most effective.
2.10.6 Implementability
Soil Alternatives S-2 and S-3 are both moderately difficult to implement, although Alternative S-
2 would be easier to implement than S-3 for several reasons. Soil Alternatives S-2 and S-3 both
require soil excavation at EA-1 adjacent to the Hobart building. Excavation along the building
footers could undermine the structures and, if soil contamination exists below or behind the
building footers, it will not be removed by this alternative. Access from property owners would
be required, and permits from the Miami Conservancy District (MCD) may be needed if staging
of excavated soils requires access or takes place on MCD property, which is adjacent to the Site.
Although Alternatives S-2 and S-3 have the same technical challenges associated with
excavation at EA-1, the engineering design for Alternative S-3 would be more complex, as it
involves design of a cap that would have to consider, and incorporate to the degree possible,
anticipated future use scenarios for EA-6. Even if EA-6 remains a parking lot or driveway, it
would still have to be designed to support such use and require more complex long-term
planning and coordination with property owners. Alternative S-3 would also require the
additional resources involved in constructing a cap and would require more subcontractors to
procure and manage. The shorter construction duration associated with excavation at EA-6
would require less coordination with and disruption to routine traffic and operational activities at
adjacent businesses. Finally, Alternative S-3 would rely on developing and enacting ICs
regarding future property use to ensure maintenance of the cap in perpetuity, whereas Alternative
S-2 would require no ICs and would not restrict future land use.
All Groundwater Alternatives RGW-2A, RGW-2B, and RGW-2C would require similar effort to
construct and would therefore have similar implementability. All alternatives would involve
similar technical challenges (e.g. ensuring proper distribution of remediation chemicals) due to
space constraints and limited access to the source area, which is partially covered by the present
overlying church addition and neighboring structures. Since Alternative RGW-2C does not rely
on recirculation, extraction wells and ex-situ treatment (of extracted groundwater from Zone A)
would not be required, reducing the amount of construction required. Therefore, Alternative
RGW-2C is the most easily implementable alternative.
2.10.7 Cost
The estimated present value cost for Soil Alternative S-2 (excavation) is $2.3 million and
Alternative S-3 (excavation and capping) is $2.5 million. However, there are no O&M or IC
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costs for Soil Alternative S-2, unlike Alternative S-3 which has both long-term O&M and IC
costs.
The estimated present worth cost of Groundwater Alternative RGW-2A (ERD) is $18.7 million;
Groundwater Alternative RGW-2B (ISCR) is $25 million; and Groundwater Alternative RGW-
2C (ISCO) is $11.9 million. However, the estimated cost of Alternative RGW-2C depends on
soil Natural Oxidant Demand (NOD), which has not been tested. If soil NOD is higher than
assumed in the FFS, the cost of this alternative may increase significantly.
The estimated present worth cost of Alternative VI-2 is $5,367,180.
2.10.8 State/Support Agency Acceptance
The State of Ohio concurs with the selected interim action, which includes Soil Alternative S-2;
Groundwater Alternative RGW-2C; and, Vapor Intrusion Alternative VI-2 in this Interim ROD.
The State's concurrence letter has been added to the Administrative Record (Appendix B).
2.10.9 Community Acceptance
During the public meeting, no verbal comments objecting to the selection of the preferred
Alternatives, Alternatives S-2, RGW-2C, and VI-2, were received. However, EPA received
written comments from one company opposing the preferred Alternative S-2 (excavation and
off-Site disposal) for addressing Spinnaker EA-6 soils. The commenter suggested the use of
institutional controls (deed restrictions) instead of excavation at EA-6. EPA has provided its
rationale for the selection of the interim remedy in the Responsiveness Summary section of this
ROD (Part 3).
2.11 Principal Threat Waste
The NCP establishes an expectation that EPA will use treatment to address the principal threats
posed at a site wherever practicable (40 CFR §300.430(a)(l)(iii)(A)). Identifying principal threat
wastes combines concepts of both hazard and risk. In general, principal threat wastes are those
source materials considered to be highly toxic or highly mobile which generally cannot be
contained in a reliable manner or would present a significant risk to human health or the
environment should exposure occur. The manner in which principal threats are addressed
generally will determine whether the statutory preference for treatment as a principal element is
satisfied. EPA considers the Residential Plume source material, which is highly mobile, and a
suspected DNAPL, to be a principal threat waste based on the definition above. Under the
selected interim remedy described below, the principal threat waste will be treated in-situ using
ISCO. The statutory preference for treatment of principal thereat wastes is met with the selected
interim remedy, Groundwater Alternative RGW-2C.
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2.12 Selected Interim Remedy
2.12.1 Summary of the Rationale for the Selected Interim Remedy
The selected interim remedy to remediate groundwater contamination source areas at the ETCA
Site is a combination of Soil Alternative S-2 (Excavation with Off-Site Disposal) for the East
Water Street soil source areas; Groundwater Alternative RGW-2C (In-Situ Treatment Using
ISCO) for the Residential Plume source area; and Vapor Intrusion Alternative VI-2 (Installation
of Sub-slab Depressurization Systems (SSDs) over the VI mitigation area) for the Residential
Plume source area.
The selected interim groundwater remedy, Alternative RGW-2C, was selected over other
alternatives because it is expected to achieve substantial risk and mass reduction through in-situ
chemical treatment of Residential Plume source area contaminants, along with downgradient
groundwater. The selected interim soil remedy, Alternative S-2, is a permanent solution to
prevent exposure to, and reduce migration of, contaminants from soil to groundwater through
excavation and off-Site disposal of contaminated EA-1 and EA-6 soils.
The selected vapor intrusion Alternative VI-2, is an interim solution to address the potential for
exposure to Site-related indoor vapor intrusion and does not treat the hazardous substances to
reduce mobility, toxicity, or volume. There is no cost-effective, practicable treatment technology
to address soil gas vapors that migrate into buildings, given the circumstances of this Site.
2.12.2 Detailed Description of the Selected Interim Remedy
The selected interim remedy to remediate groundwater contamination source areas at the ETCA
Site is a combination of Soil Alternative S-2 (Excavation with Off-Site Disposal) for the East
Water Street soil source areas; Groundwater Alternative RGW-2C (In-Situ Treatment Using
ISCO) for the Residential Plume source area; and Vapor Intrusion Alternative VI-2 (Installation
of SSDs) for the Residential Plume source area.
The major components of the interim remedy selected for the East Water Street soil source areas
(Soil Alternative S-2) include:
• Excavation of approximately 9,110 cubic yards (yd3) of contaminated soils from the
area behind the former Hobart Cabinet loading dock and excavation of approximately
753 yd3 of contaminated soils under the asphalted-portion of the Spinnaker Coatings
western parking lot;
• Collection of confirmation samples from excavated areas to ensure soil cleanup levels
are met;
• Loading of contaminated soils into dump trucks with transportation to an off-Site
licensed landfill for disposal;
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• Backfill of excavated areas with gravel or clean soil; and
• Dust suppression during excavation and loading of the dump trucks and covering of
dump trucks with a tarp to minimize dust generation and minimize risks to the
community.
The major components of the interim remedy selected for the Residential Plume source area
(Groundwater Alternatives RGW-2C and Vapor Intrusion Alternative VI-2) include:
• In-situ chemical oxidation of the Residential Plume source area and groundwater
downgradient of the source area (referred to as the "groundwater treatment area") from
Walnut to Union Streets;
• Groundwater monitoring to ensure cleanup goals (70 to 90 percent reduction in dissolved
total Volatile Organic Compound (VOC) mass throughout treatment area) are met and to
ensure the East Well Field is not adversely impacted. Any reduction of VOC mass at or
beyond 70 percent will be considered successful for this interim action. EPA expects
actual reduction of the VOC mass to be in the range of 70 to 90 percent, with any
additional reduction serving as a greater success;
• Installation of SSDs (similar to radon mitigation systems) at approximately 156 buildings
located above the groundwater treatment area plus an additional two-block buffer to
Frank Street (collectively, from Walnut to Frank Streets); and,
• Post-installation verification testing of all SSDs to ensure the systems are operating
properly.
2.12.3 Cost Estimate for Selected Interim Remedy
The cost estimate for the selected interim remedy is summarized below and is in Appendix C of
this ROD. The cost estimate is based on the best available information regarding the anticipated
scope of the interim remedial action. Changes in the cost estimates are likely to occur as a result
of new information and data collected during the engineering design of the interim remedy.
Major changes may be documented in the form of a memorandum in the Administrative Record
file, an Explanation of Significant Differences, or a ROD amendment.
The present worth cost to implement Alternative S-2 is approximately $2.3 million, which
includes $1.8 million in capital costs with no O&M costs.
The cost to implement Alternative RGW-2C is approximately $12 million. This includes a
capital cost of $6.3 million and a present worth O&M cost of $2.3 million over a 10-year period.
Annual costs are estimated at $128,000 for 10 years, with an additional $25,000 every five years
for the five-year review. However, costs related to ISCO treatment may also increase if, during
pre-design, the natural oxidant demand of the aquifer is determined to be higher than anticipated.
If costs for ISCO increase significantly, EPA will reevaluate the other viable in-situ treatment
options (Alternatives RGW-2A and RGW-2B). If EPA determines that one of the other options
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is better suited given the aquifer NOD, then EPA will document this decision in an Explanation
of Significant Differences (ESD) or ROD Amendment
The cost to implement Alternative VI-2 is $5.4 million, which includes $1.3 million in capital
costs and $2.8 million in present-worth O&M costs over a 15-year period. Annual costs are
estimated at $308,000 for 15 years, with an additional $25,000 every five years for the five-year
review. If the timeframe for operation of the vapor mitigation systems is reduced to 10 years, the
present worth cost of the remedy is reduced to $1.5 million.
2.12.4 Expected Outcomes of the Selected Interim Remedy
At the completion of the interim soil remedy (Alternative S-2), potential exposures due to
inhalation of soil vapors to future residents and current/future industrial/commercial workers will
be eliminated through excavation of contaminated soils at Hobart EA-1 and Spinnaker EA-6.
The migration of contaminated soil to groundwater will also be minimized.
Groundwater Alternative RGW-2C will destroy 70 to 90 percent of the source area mass at the
Residential Plume. Removing 70 to 90 percent of the contaminant mass at the Residential Plume
source area (Walnut to Mulberry) will substantially deplete the amount of PCE available in Zone
A to feed the downgradient portion of the plume (Mulberry to Union Streets). This, in turn, will
reduce the contaminant concentrations throughout the downgradient plume. Reduction of COCs
in groundwater will also allow for evaluation of an expanded range of groundwater alternatives
(and likely successful implementation) to address Site-wide groundwater in the final OU1 ROD.
Finally, Alternative VI-2 will mitigate the potential for exposure to Site contaminants in indoor
air during in-situ groundwater treatment.
2.13 Statutory Determinations
Under CERCLA Section 121 and the NCP, the lead agency must select remedies that are
protective of human health and the environment, comply with ARARs (unless a waiver is
justified), are cost-effective, and utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum extent practicable. In addition,
CERCLA includes a preference for remedies that employ treatment that permanently and
significantly reduces the volume, toxicity, or mobility of hazardous substances as a principal
element and a bias against off-Site disposal of untreated wastes. The following sections discuss
how the selected interim action meets these statutory requirements.
2.13.1 Protection of Human Health and the Environment
The selected interim soil remedy, Alterative S-2, will protect human health and the environment
by permanently removing the contaminated soils in both EA-1 and EA-6, eliminating the
potential risk of future contact (via inhalation) with contaminants and the potential for
contaminants to leach to groundwater in the future. The current non-cancer risks associated with
residential (7.3), future industrial/commercial (1.6), and current/future construction worker (1.8)
exposures to EA-1 subsurface soils are all greater than 1. The selected interim soil remedy, by
achieving the soil RALs of 44 ppb for PCE and 34 ppb for TCE, will reduce the non-cancer
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hazard risks (HI) to less than one. There are no short-term threats associated with the selected
interim soil remedy that cannot be reliably controlled.
The selected interim groundwater remedy, Alternative RGW-2C, will destroy more than 70
percent of VOC mass in groundwater at the source area and throughout the entire targeted
treatment area through in-situ treatment. Alternative RGW-2C will also not produce
dechlorination byproducts (TCE, cDCE, and VC) as PCE and TCE are reduced during treatment.
Although there is a risk of solubilizing naturally-occurring metals during treatment, solubilized
metals are not expected to migrate more than a few hundred feet beyond the treatment area,
which would be 1,000 feet upgradient of the East Well Field. Existing City of Troy ordinances
governing the use of private potable water supply wells would continue to minimize the risk of
human exposure to contaminated groundwater.
The vapor intrusion mitigation systems, Alternative VI-2, will prevent the potential for Site-
related contaminants in vapor, if they migrate from the subsurface into indoor air, to be present at
concentrations which represent a threat to human health.
2.13.2 Compliance with Applicable or Relevant and Appropriate Requirements
This selected interim remedy will comply with all ARARs.
2.13.3 Cost Effectiveness
The selected interim remedy is cost-effective and represents a reasonable value for the money to
be spent. The NCP requires that "a remedy shall be cost-effective if its costs are proportional to
its overall effectiveness." (See the NCP at 40 C.F.R. §300.430(f)(l)(ii)(D)). This was
accomplished by evaluating the overall effectiveness of those alternatives that satisfied the
threshold criteria {i.e., were both protective of human health and the environment and ARAR-
compliant). EPA evaluated the overall effectiveness of the remedies by assessing the following
three of the five balancing criteria: (1) Long-term effectiveness and permanence; (2) Reduction
in toxicity, mobility, and volume through treatment; and (3) Short-term effectiveness. EPA then
compared the overall effectiveness to the costs to determine cost effectiveness. The overall
effectiveness of the remedial alternatives selected for the ETCA Site was determined to be
reasonable for their costs and hence these alternatives are considered to be cost-effective.
The estimated present worth of the selected interim remedy is $19.6 M. This engineering cost
estimate is expected to be within +50 to -30 percent of the actual project cost. EPA believes that
the selected interim remedy's in-situ treatment of groundwater using ISCO (Alternative RGW-
2C) will provide an overall level of protection comparable to groundwater Alternatives RGW-2A
and 2B but at a significantly lower cost. EPA also believes soil excavation (Alternative S-2) will
provide the highest degree of long-term effectiveness and permanence compared to Alternative
S-3 (excavation and capping) because contaminated soil is permanently removed off-Site instead
of leaving a potential source of contamination in place.
45
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2.13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
(or Resource Recovery Technologies) to the Maximum Extent Practicable
EPA has determined that the selected interim remedy represents the maximum extent to which
permanent solutions and treatment technologies can be utilized in a practicable manner at the
Site. Of those alternatives that are protective of human health and the environment and comply
with ARARs, EPA has determined that the selected interim remedy provides the best balance of
trade-offs in terms of the five balancing criteria, while also considering he statutory preference
for treatment as a principal element and bias against off-Site treatment and disposal and
considering State and community acceptance.
The selected interim groundwater remedy, Alternative RGW-2C, treats source materials
constituting principal threats at the Site and achieves substantial risk and mass reduction through
in-situ chemical treatment of Residential Plume source area contaminants and downgradient
groundwater. The selected interim soil remedy, Alternative S-2, is a permanent solution to
prevent exposure to, and reduce migration of, contaminants from soil to groundwater through
excavation and off-Site disposal of contaminated EA-1 and EA-6 soils.
The selected interim vapor mitigation alternative, Alterative VI-2, addresses the potential for
exposure to Site-related indoor vapor intrusion and does not treat the hazardous substances to
reduce mobility, toxicity, or volume. There is no cost-effective, practicable treatment technology
to address soil gas vapors that migrate into buildings, given the circumstances of this Site.
2.13.5 Preference for Treatment as a Principal Element
By treating the Residential Plume contaminated source material and downgradient groundwater
through in-situ chemical oxidation, the selected interim remedy satisfies the statutory preference
for remedies that employ treatment as a principal element.
2.13.6 Five-Year Review Requirements
CERCLA § 121(c) and the NCP §300.430(f)(5)(iii)(C) provide the statutory and legal bases for
conducting Five-Year Reviews. This remedy is expected to result in hazardous substances
remaining on-Site in the groundwater above levels that allow for unlimited use and unrestricted
exposure. A statutory review will be conducted every five years after initiation of the interim
remedial action to ensure that the remedy is, or will be, protective of human health and the
environment.
2.14 Documentation of Significant Changes
The Proposed Plan for this interim remedy at the ETCA Site was released for public comment on
June 25, 2018. The Proposed Plan identified the Preferred Interim Alternatives of soil
excavation with off-Site disposal for the East Water Street Soil Source Area (Alternative S-2)
and In-Situ treatment using chemical oxidation (Alternative RGW-2C) and installation of sub-
slab depressurization systems (Alternative VI-2) for the Residential Plume Source Area. EPA
reviewed all written and verbal comments submitted during the public comment period. It was
46
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determined that no significant changes to the remedy, as originally identified in the Proposed
Plan, were necessary or appropriate.
47
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Part 3: Responsiveness Summary
This Responsiveness Summary documents public participation in the interim remedy selection
process for the East Troy Contaminated Aquifer (ETCA Site). Comments received during the
30-day public comment period and during the June 27 public meeting are included in this section
of the Interim ROD, along with EPA's responses to these comments. The public comment
period for this response action ran from June 25, 2018 to July 25, 2018.
3.1 Stakeholder Comments and Lead Agency Responses
Verbal comments were received during the June 27, 2018 public meeting at the Troy City Hall,
100 S. Market Street, Troy, Ohio 45373. None of the commenters expressed opposition to
EPA's proposed interim remedy.
1. One resident stated that she has lived in her house for 23 years. She's had nine dogs in
the past, and she is concerned that all of them lived only to the age of eight. She has two
dogs now and one is eight years old, and she is concerned that ETCA Site contaminants
could be causing a risk to her dogs.
Risks from exposure to ETCA Site contaminants would mainly occur through drinking,
inhaling, or coming in dermal contact with contaminated groundwater or contaminated
soils. However, all residents living in the area of the ETCA Site are connected to the City
of Troy municipal water supply and none are currently using contaminated groundwater
for drinking water, showering, etc. Dogs may be exposed to contaminants in surface
soils. However, surface soils at the ETCA Site do not exhibit unacceptable levels of Site
contaminants. Soil contaminants are present at a depth of 2 to 4 feet below ground
surface (bgs) at Spinnaker and at 4 to 10 feet bgs at Hobart. Therefore, the risk of a pet
being exposed to ETCA Site contaminants is very low.
2. One resident requested more information as the cleanup proceeds and suggested the City
of Troy broadcast future Site meetings so residents are aware of the cleanup.
EPA is committed to updating the community regarding all ETCA Site cleanup activities
using fact sheets, mailings, and public meetings. ETCA Site information and cleanup
updates are also posted on the web, at www, epa. sov/super fund/east-troy-aquifer. The
ETCA Site Administrative Record (including reports, the Proposed Plan, and other
information) is also available for viewing at the Troy-Miami County Public Library,
Local History Branch, 100 W. Main Street. The City of Troy posts videos of all city
council and city committee meetings, including the EPA public meeting on the proposed
cleanup plan, on the City of Troy's website at troyohio.gov. To access a video
presentation of the June 27, 2018 EPA public meeting, interested residents can click on
the "live video " section of the City of Troy homepage. After clicking on "live video ",
residents will be taken to a link to the City of Troy YouTube channel where the meeting
video is located.
48
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3. One resident communicated thanks that EPA is cleaning up the Site but also expressed
concern about taking contaminated material from one site and disposing of it at another.
He questions if EPA is just converting one problem to another.
The treatment of contaminated EA-1 and EA-6 soils is cost prohibitive. On the other
hand, the continued presence of ETC A Site contaminants in EA-1 and EA-6 soils would
increase the chance of future human exposures and they may serve as an ongoing source
to groundwater contamination at the Site. Excavation is a commonly used remediation
method where in-situ soil treatment will not work or where it is not cost-effective.
Excavated EA-1 and EA-6 soils will be disposed of at a licensed off-Site landfill that is
specifically designed and constructed to safely contain the types of waste materials found
at the ETCA Site.
4. One resident expressed support for redeveloping the riverfront on the Hobart and
Spinnaker properties. She asked what is needed to excavate and rebuild the area, and she
asked whether this is a possibility.
The EA-1 and EA-6 soil areas planned for excavation under the interim remedial action
will meet cleanup goals that are protective for unlimited use and unrestricted exposure
(UU/UE). There is nothing about the interim remedy that EPA is selecting for the EA-1
and EA-6 soil areas that would preclude future redevelopment of the riverfront.
5. One resident's home was tested for indoor vapors previously, and she requested that her
home be monitored moving forward. Her children attend St. Patrick's school, and she
has an on-going concern for the safety of the children. She also works across the street
from Hobart and is concerned about exposures during the cleanup of the Hobart property.
She asked how EPA will monitor the residences and businesses in the area.
EPA will install vapor abatement systems between Walnut and Frank Streets as part of
the interim remedial action. In addition to preventing exposure to contaminated vapors,
EPA will take precautions to minimize the risks to the community during the cleanup
(excavation) of the EA-1 soils on the Hobart property. Risks will be minimized by
employing dust suppression (spraying of water to wet the contaminated soils) during
excavation and dump truck loading. Dump trucks will also be covered with tarps during
transport to prevent wind and rain from blowing contaminated soil into the air. The tires
and exterior of the dump trucks will also be washed before leaving the Site so that soil is
not tracked through neighboring streets. These precautions will minimize the possibility
of generating airborne dust and thus eliminate the potential risk of inhalation of
contaminated dust during cleanup.
3.2 Technical and Legal Comments
6. One response is provided for the following similar comments:
A commenter stated that the Proposed Plan proposes a remedy for the EA-6 area on the
Spinnaker property that is not necessary to achieve protectiveness. The commenter states
49
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that EPA has calculated an unreasonable hypothetical future risk by assuming a
residential future use of the property. The commenter states that this land use is not
currently allowed by City zoning rules and could be legally precluded to prevent such
exposures.
A commenter stated that the Spinnaker property is zoned for industrial use and has been
used as an industrial site for more than 100 years. The commenter stated that EPA
arbitrarily created the need for a remedy in this area by hypothesizing a future residential
use in the Proposed Plan that could not occur without a zoning change. The Proposed
Plan asserts that these hypothetical "future residents" could be exposed to "inhalation of
vapors from subsurface soil that are brought to surface during intrusive excavation or
landscaping." The commenter stated that the Proposed Plan further makes the reckless
assumption that such future residents would use the water "as a source of potable water"
which could result in "inhalation of vapors released from potable use activities
(showering and washing dishes and clothes)"
A commenter stated that EPA's hypothetical, future potential risk scenarios are baseless.
Any residential use of the property would require a zoning change, and even in that
instance, U.S. EPA has already recognized that existing city ordinances sufficiently
address reasonable assumptions regarding current and future use of groundwater. There
is simply no reasonable basis for the agency's hypothetical future risk scenarios, which
contradict its own conclusions. Moreover, a standard deed restriction, which OEPA and
U.S. EPA rely on routinely to prohibit residential use of properties, could be used to
reasonably preclude residential use. That restriction could also alert future owners to
groundwater use restrictions.
EPA guidance recommends that EPA conduct human health risk assessments (HHRA)
that address reasonable maximum exposure (RME) conditions. In other words, EPA
should address the maximum exposure that can be reasonably anticipated to occur in the
future. Therefore, EPA assessed the risk to a hypothetical future resident living in the
EA-6 soil area to determine whether any remedial action is necessary to ensure the future
protectiveness of that resident from exposures to the contaminated soil and contaminated
groundwater. The HHRA for EA-6 determined that there would be an unacceptable risk
to a future resident living at EA-6, so EPA is taking the action described in this Interim
ROD to address that risk.
While institutional controls, in the form of legal restrictions on the use of the EA-6 area,
are a possible remedy to achieve protectiveness, they are not considered to be as effective
in the long-term as soil excavation. Leaving ETC A Site contaminants in place increases
the chance of a future human exposure to soil contamination at depth or through vapor
intrusion. Further, leaving contaminated soil at depth may result in the ongoing release
of contaminants to groundwater at the Site.
The estimated cost for the EA-6 portion of the excavation alternative (S-2) is
approximately $290,000, and the estimated cost for implementing, maintaining and
50
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monitoring ICs in perpetuity at EA-6 is approximately $320, ()()()'. Given that the cost to
conduct an excavation at EA-6 is less than the cost of implementing, maintaining and
monitoring institutional controls in perpetuity, EPA has determined that excavation is the
appropriate remedial action for EA-6.
7. One commenter said that, for the Spinnaker property, the Risk Assessment arrived at
cumulative exposure risks reflected in hazard indices that are unrealistically and
unreasonably high. These indices are largely based on exposure to chemicals in
groundwater, not soil present on the property. However, the groundwater concentrations
used for these calculations are not present on the Spinnaker property and will not be
present in the future. In addition, some exposure pathways were assumed that are
incomplete.
The approach that EPA used to assess current andfuture risk at the ETCA Site is
consistent with EPA HHRA guidance. Many of the assumptions used to assess Site risks
are conservative, but such conservativeness is consistent with EPA's mission and
direction to address RME conditions. EPA agrees that the total estimated non-cancer
hazard index (HI=8.9) at the East Water Street Plume is largely driven by groundwater
concentrations (HI=6.8) measured upgradient of the Spinnaker property (EA-6);
however, EPA would still be required to take action to address subsurface soil
contamination at EA-6 based solely upon the calculated hazard index associated with
subsurface soil (HI=2.1), which exceeds EPA 's target non-cancer hazard index of 1.
8. One response is provided for the following similar comments.
One commenter stated that "U.S. EPA is proposing remediation of EA-6 on the
Spinnaker property, to reduce the risk of soil leaching to groundwater. However, twenty-
four years of soil and groundwater data at the property confirm that groundwater
contamination on the Spinanker property has an off-Site source and the groundwater does
not exceed the EPA Safe Drinking Water Act (SDWA) Maximum Contaminant Levels
(SDWA MCLs). All groundwater monitoring data establishes that the soil is not leaching
into groundwater at concentrations that exceed SDWA MCLs."
A commenter stated that EPA has calculated Remedial Action Objectives (RAOs) for soil
on the Spinnaker property which are unncessary because the groundwater conditions do
not exceed the SDWA MCLs. The commenter states that even if the RAOs are
necessary, they have not been calculated correctly.
Albeit the groundwater underneath the Spinnaker property does not currently exceed
SDWA MCLs, removing the contaminated soil will provide protection from the soils
serving as a source of groundwater contamination into the future. These leaching
cleanup levels were derived in accordance with Ohio EPA guidance and policy, and with
their participation and concurrence. Further, EPA is taking an interim action at EA-6 to
prevent the future exposure of residents to TCE in soil and groundwater that may pose an
unacceptable non-cancer hazard.
^ IC costs calculated assuming $25,000 to complete a Five-Year Review Report every five years over a 60-year period.
51
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Given that the cost to conduct an excavation atEA-6 is less than the cost of
implementing, maintaining and monitoring institutional controls in perpetuity, EPA has
determined that excavation is the appropriate remedial action for EA-6 at this time (See
response #6).
9. One commenter stated that there is almost certainly a separate source of PCE on the
Hobart property that EPA has not fully investigated.
EPA will be implementing an excavation remedy at the EA-1 area of the Hobart property
to address PCE contamination as part of this Interim ROD. As that excavation is
designed and conducted, additional sampling will be conducted to ensure that residual
PCE levels are below concentrations that would be a concern for leaching to
groundwater.
10. One commenter stated that there is no action that can be taken at EA-6 that will alter the
current situation. The future outcome for all three remedial aternatives evaluated in the
FFS for EA-6 soil on the Spinnaker proerty will be exactly the same: concentrations of
cDCE in shallow groundwater below the SDWA MCL that originate from an off-Site
source.
EPA respectfully disagrees. EPA is taking an action atEA-6 soils based on the results of
the risk assessment for EA-6, which indicates an unacceptable non-cancer hazard to
hypothetical future residents from TCE and PCE contamination. EPA assesses this risk
to account for the, admittedly unlikely, but not impossible, scenario where the EA-6
property could be redeveloped for residential use in the future.
EPA also disagrees that the outcome from all three alternatives would be the same. In
fact, that is why EPA conducts an evaluation of the short- and long-term effectiveness of
each of the remedial alternatives. While institutional controls, in the form of legal
restrictions on the use of the EA-6 area, are a possible remedy to achieve protectiveness,
they are not considered to be as effective in the long-term as soil excavation. Leaving
ETCA Site contaminants in place increases the chance of a future human exposure to soil
contamination at depth or through vapor intrusion and also may result in the ongoing
release of contaminants to groundwater at the Site. Given that the cost to conduct an
excavation at EA-6 is less than the cost of implementing, maintaining and monitoring
institutional controls in perpetuity, EPA has determined that excavation is the
appropriate interim remedial action for EA-6 at this time (See response #6).
EPA recognizes that the full extent of the East Troy Site contamination is not likely
addressed by this interim remedial action. Contamination that poses an unacceptable
risk at the Site that is not addressed by the interim remedial measures will be addressed
in further cleanup action(s).
52
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53
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FIGURES
54
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6,A
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 1
SITE LOCATION MAP
-A'l
X
uL
\
ST SulTRAC
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Legend
Troy Production Well
,¦=*—i Remedial Investigation
I '• Study Area
0 500 1,000
Feet
Source: Bing Maps Hybrid 2013
Reference Map
¦ tt'mrttr) \
%
i
"
-------
Legend
@ Ohio EPA Well
0 Troy Monitoring Well
0 MCD Well
O Troy Production Well
I 1 Approximate Areas of
I I 1995 Soil Excavations
Feature Boundary
I Total Chlorinated VOCs
l >100 |jg/L (ppb) Plume Area
Total Chlorinated VOCs
<100 pg/L (ppb) Plume Area
Notes:
MCD - Miami Conservation District
OEPA- Ohio Environmental Protection Agency
P - City of Troy Supply Well
ppb - Parts per billion
Rl - Remedial Investigation
S - Shallow
T - Miami Conservancy District Monitoring Well
VOC - Volatile Organic Compound
pg/L - Micrograms per liter
400
Feet
600
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 2
SITE FEATURES
ST SulTRAC
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Primary
Contaminant
Sources
Former Dry Cleaner
at Walnut and Main
(10 E. Main)
Hobart Cabinet (Hobart)
Loading Dock and
Building Area and
Vapor Degreaser
(Building Sources Unknown)
Spinnaker Coatings LLC
(Spinnaker) West Parking Lot
(Including KMW-10 area and
Former Dry Cleaner location)
Primary
Contaminant
R/T Mechanisms
Leaks From Sewers
Receiving Historic Process
Wastewater Discharges
Spills
Surface
Disposal
Primary
Affected
Media
Secondary
Contaminant
R/T Mechanisms
Volatilization
to Soil Gas1
Sorption/Diffusion
in Low Permeability
Subsurface Soil Zones
Leaching/
Percolation[
Discharge
Fugitive Emissions'
Volatilization1
Irrigation
Secondary
Affected
Media
Indoor Air
Groundwater
Ambient Air
Homegrown
Produce
Exposure
Routes
Inhalation
Potentially Exposed Human Receptors
CF
CF CF CF Construction and
Resident l/C Worker Recreationalist Utility Workers
Ingestion
Dermal Contact
Inhalation
•
—
i
i
i
i
#•
©c
•
i
i
Surface Water/
Incidental Ingestion
—
—
— k
—
Sediment
Dermal Contact
—
—
— k
—
Inhalation
Ingestion
Dermal Contact
Ingestion
Incidental Ingestion
Dermal Contact
»
•
—
• «
•
—
©
•
—
o
—
—
—
Ingestion
—
—
—
Dermal Contact
0
—
—
—
Inhalation
o
—
—
--
Notes:
R/T
o
bgs
C
F
l/C
Release/transport
Potentially complete, but insignificant exposure pathway - will not be retained for quantitative analysis
Potentially complete exposure pathway - retain for quantitative analysis
Incomplete exposure pathway; will not be retained.
Below ground surface
Current
Future
Industrial - Commercial
EAST TROY CONTAMINATED AQUIFER SITE
REMEDIAL INVESTIGATION
TROY, OHIO
FIGURE 3
CONCEPTUAL SITE MODEL
ST SulTRAC
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Phase I Soil Sample
(May-June 2012)
Phase II Soil Sample
(February 2013)
Soil sample concentrations in
micrograms per kilogram (pg/kg).
Sampling locations shown without
associated analytical results indicate
that samples were collected; however,
all results were below site screening
levels.
N
0 200 400
1 I I I I
Feet
Notes:
CHE - Cherry Street
CLY - Clay Street
CRA - Crawford Street
FRA- Franklin Street
HER - Herrlinger V\fey
J - Estimated value
MAI - Main Street
MUL - Mulberry Street
PCE - Tetrachloroethene
RAC - Race Street
SB - Soil Boring
TCE - Trichloroethene
TPD - Troy Police Department
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 4
RESIDENTIAL AREA
SOIL SAMPLING RESULTS
ST SulTRAC
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m
A
SB318(0.5')
SB315(0.5')
7
Benzene - 1.3J
PCE - 26J
TCE - 17J
TCE - 1,400 J
X
SB318 (41)
SB315(4")
TCE - 440
PCE - 860 J
•*T
SB318(8')
TCE - 40,000 J
TCE - 89J
SB315 DUP (4')
SB318 PUP (8')
PCE - 730J
Benzene - 87 J
TCE - 38,000 J
PCE - 58 J
SBSlSfS1)
TCE - 1,800
PCE - 180J
TCE - 3,600J
1 3,1,2-TCA - 47 J
SB003 (1')
PCE
1,500
TCE
870
SB003 (4')
cis-l,2-DCE -
36
PCE
2,000
1,1,2-TCA -
2.3J
TCE
1,400
%
5B319 (0.5')
PCE
900 j
TCE
3,800 !
SB319(4')
PCE
1,500 !
TCE
5,300
1,1,2-TCA -
93 J 1
SB319(6'J
PCE
1,100
TCE
3,600
cis-l,2-DCE -
31J |
1,1,2-TCA
30J
SB319 (81)
PCE
2,500 1
TCE
1,900 |
cis-l,2-DCE -
35 J
- 4,000
- 1,700
SB317 (4')
- 920 J
- 20,000 J
it*
SB317 (8')
Benzene
32 J
PCE
680
TCE
3,800
a
WM
SB002(1')
PCE
110
TCE
89
SB002 (41)
cis-3,2-DCE -
3.5J
PCE
1,800
1,1,2-TCA
6.9
TCE
1,700
PCE
TCE
y
TCE
SB321 (0.5')
PCE
230 J
TCE
340 J
SB321(4')
PCE
730
TCE
4,000
SB321(8')
PCE
54 J
TCE
410
SB004(1')
PCE
13 I
SB316(0.5')
1,700
- 350 J
SB316 PUP (0.5')
PCE
SB316(4')
PCE
TCE
- 72,000
- 16,000 J
SB316 (8')
PCE
TCE
1,400
- 360
cis-l,2-DCE - 11J
SB316 DliP (8')
PCE
TCE
cis-12-DCE
1,300
360
13 J
HOB1 (6-8')
HOBS (6-8')
SB325(0.5')
PCE
250
TCE
41J
SB325 (6')
PCE
920
TCE
360
SB325 (8')
PCE
260
TCE
88 J
HOB2(6-8')
HOB7 (SS)
™ J
t
TCE
HOB-5 (10-12')
- 0.30 J
HOB-5 (16-18")
SB320 (0.5*)
PCE
TCE
420
- 240 J
SB320 (2')
PCE
1,400
TCE
1,100
SB320 (4)
PCE
1,500
5TPl(6-8')
STP1 (12-14')
• 1 *
TCE
SB320 (10')
Benzene
PCE
TCE
SB320 (12')
PCE
TCE
SB320 (14')
500
PCE
TCE
SB320 (16')
PCE
TCE
- 2,400
- 2,800
1,1,2-TCA
17 J
%
SB324 (0.5')
PCE
59
TCE
1.8 J
SB324(5')
PCE
4.9 J 1
TCE
18
cis-l,2-DCE -
1.6 J
SB324(7')
PCE
720
TCE
230
M 7
i
-------
SB007 (4')
SB007 (6')
SB008(1')
TCE
19
SB008 (4')
TCE
21
SB008(6')
TCE
16J
ds-1,2-DCE
TCE
PCE
SB303 (2')
\ * Jr 1
cis-l,2-DCE
SB015{4')
;"\3
u
SB015-DUP (4')
ds-l,2-DCE - 180
¦ • - - i - ¦« . . I
SB303 (4')
cis-1,2- PCE - 4,400
SB303 (6')
ds-l,2-DCE - 220 J
SPN1(2-
PCE
110 J
1,300
SB3Q3 (8')
SB303(10')
PCE
SB014 (!')
PCE
2.7 J
TCE
3.8 J
SB014 (4')
ds-l,2-DCE -
2.3 J
PCE
11
TCE
1,200 1
SB014 (6')
| TCE
14 |
SB014-DUP (6')
PCE
1.9 J 1
TCE
17 |
SB015 (&')
J SB302(0.5')
1 ds-l,2-DCE -
12
TCE
9.8
SB302 (4')
cis-l,2-DCE -
2,800
PCE
21J
TCE
170 J
SB302 (8')
cis-l,2-DCE -
1.6 J
TCE
1.5J
SPNZ (6-8')
SPN2-DUP (6-B1)
SB300 (0.5')
TCE
mmm
SB011 (5')
PCE
2.4J |
TCE
56
SB011 (7')
TCE
45
SB011(9)
cis-l,2-DCE -
9.5
TCE
63
SB300 (41)
TCE
SB3Q0 (81)
TCE
SB3Q0 (10')
SB301 (0.5'
mm
Lil
TCE
4.7 J
SB301(4')
ds-l,2-DCE -
890
PCE
160 J
TCE
12,000
SB301 (81)
ds-l,2-DCE -
16J
5B010 (5')
PCE - 3.2J
i
TCE - 180
SB312 (0.51)
SB010 (71)
TCE - 22 1
TCE - 16
SB312DUP(0.5')
SBO 10-DUP (7')
TCE - 17 |
PCE - 2.4J
SB312 (4)
TCE - 61
E
PCE - 47J 1
SB010 (9*)
TCE - 420
TCE - 18
SB312 DUP (4')
rf \ 'J
PCE - 77 J
TCE - 910
SB312(8)
TCE - 13J |
ds-1,2-DCE
TCE
SB306 (4')
SB306 (8')
SB307 (8')
PCE
SB307 (14')
SB009(T)
\
SB306 (10')
SB308(0.5")
4
SB309(0.5')
PCE - 8.5
£
- I
ds-l,2-DCE - 12 J
TCE - 1.4 J
PCE - 210 J
SB308 (4')
.P
TCE - 350
PCE - 18
s
SB309 (41)
TCE - 1.7 J
PCE - 160J
SB308 (8')
TCE - 430
PCE - 8
SB309 (10')
SB308 (12')
PCE - 14
PCE - 14
TCE - 52
TCE - 0.55 J
5B310 (0.5')
PCE
74 J
TCE
820
SB310 (41)
PCE
47 J
TCE
730
SB310 (81)
PCE
6.2
TCE
200
58311(0.5')
ds-l,2-DCE -
1.8J
TCE
46
SB 311 (4')
ds-l,2-DCE -
160 J
PCE
74 J
TCE
2,300
SB311 (8')
SB313 (0.5')
SB313 PUP (0.5')
SB313 (4')
TCE
SB313(6')
ds-l,2-DCE
SB314 (0.5')
TCE
23J
SB314 (61)
TCE
1,400
SB314(8')
TCE
11
TCE
SB313DUP (6')
ds-l,2-DCE
16
,¦ Phase I Soil Sample
,; / (May-June 2012)
A Phase II Soil Sample
^ (February 2013)
Additional Phase II Soil
^ Sample (December 2013
and January 2014)
Approximate Extent of
Soil Exceeding Industrial
Screening Levels
Approximate Extent of
Soil Exceeding Residential
Screening Levels
Approximate Area with
Highest VOC Detections
Based on Shaw 2006 Report
Soil sample concentrations in
micrograms per kilogram (pg/kg).
Sampling locations shown without
associated analytical results indicate
that samples were collected; however,
all results were below site screening
levels.
N
25
Feet
Notes:
cis-1,2-DCE - a*s-1,2-Dichloroethene
DUP - Duplicate
J - Estimated value
PCE - Tetrachloroethene
SB - Soil Boring
SPN - Spinnaker
TCE -Trichloroethene
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 6
SPINNAKER SOIL
SAMPLING RESULTS
ST SulTRAC
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-------
Legend
© Ohio EPA Well
Phase I Rl Well
Phase II Rl Well
0 Troy Monitoring Well
(J) KC Monitoring Well
0 MCD Well
Geoprobe Location
HRSC Waterloo Groundwater
Profiling (April-May 2013)
W VAS Location
1 Direction of Groundwater Flow
Total Chlorinated VOCs
5 (ppb)
1,000 (ppb)
500 (ppb)
100 (ppb)
Notes:
Total concentration is the sum of PCE. TCE,
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DC E - cis-1,2-Dichloroethene
D - Deep
EPA - US Environmental Protection Agency
GZA- Spinnaker Site/ Kimberly Clark Monitoring Well
ETCA - East Troy Contaminated Aquifer
KC - Kimberly Clark
KMW - Spinnaker Site/ Kimberly Clark Monitoring Well
MCD - Miami Conservation District
MCL - Maximum Contaminant Level
MOR - Morehead Street
ND - Not detected
OEPA - Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
T - Miami Conservancy District Monitoring Well
TCE - Trichloroethene
VAS - Vertical Aquifer Sample
VC - Vinyl Chloride
VOC - Volatile Organic Compound
WAL-Walnut Street
100 200
Feet
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 7
RESIDENTIAL AND EAST WATER STREET
TOTAL CHLORINATED VOCs
ST
SulTRAC
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-------
-------
/ >
- 11,000
Chlor
V
Sample concentrations in tig/m3
(Micrograms per cubic meter).
Sampling locations shown without
associated analytical results indicate
that samples were collected; however,
all results were below site screening
levels.
Legend
Vapor Intrusion
Monitoring Locations
(January 2012)
N
300
Feet
Exceeds residential indoorair VISLfor target
hazard quotient of land target risk of 1E-06
Exceeds commercial indoor air VISL for target
hazard quotient of 1 and target risk of IE-OS
Exceeds residential sub-slab soil gas VISL for target
hazard quotient of 1 and target risk of 1E-06
Exceeds commercial sub-slab soil gas VISL for target
hazard quotient of 1 and target risk of 1E-06
Notes:
1.2-DCA -1,2-Dichloroethane
1,2,4-TCB -1,2,4-Trichlorobenzene
1.3-B- 1,3-Butadiene
1.4-DCB -1,4-Dichlorobenzene
a-C - alpha-Chlorotoluene
Bromo - Bromodichloromethane
cis-1,2-DCE - cis-1,2-Dichloroethene
Chlor - Chloroform
CT - Carbon Tetrachloride
Dibromo - Dibromochloromethane
EB - Ethyl Benzene
lA - Indoor Air Sample
J - Estimated value
J+ - Results estimated, but may be biased high
MCL - Maximum Contaminant Level
PCE - Tetrachloroethene
RSL - Regional Screening Level
SS - Sub-Slab Sample
TCE - Trichloroethene
VISL - Vapor Intrusion Screening Level
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 9
PHASE I VAPOR INTRUSION
MONITORING RESULTS
ST SulTRAC
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-------
Sample concentrations in pg/m3
(Micrograms per cubic meter).
Sampling locations shown without
associated analytical results indicate
that samples were collected; however,
all results were below site screening
levels.
Legend
Vapor Intrusion
Monitoring Locations
(August 2012 and
April 2013)
N
+
150 300
J I I I
Feet
Exceeds residential indoor air V ISLfor target
hazard quotient of 1 arid target risk of IE-OB
Exceeds commercial indoor air VISLfortarget
hazard quotient of 1 and target risk of 1E-06
Exceeds residential sub-slab soil gas VISLfortarget
hazard quotient of 1 and target risk of 1E-06
Exceeds commercial sub-slab soi I gas VISL for target
hazard quotient of 1 and target risk of 1E-06
Notes:
1.2-DCA- 1,2-Dichloroethane
1,2,4-TCB - 1,2,4-Trichlorobenzene
1.3-B- 1,3-Butadiene
1.4-DCB -1,4-Dichlorobenzene
a-C - alpha-Chlorotoluene
Bromo - Bromodichloromethane
cis-1,2-DCE - cis-1,2-Dichloroethene
Chlor- Chloroform
CT - Carbon Tetrachloride
Dibromo - Dibromochloromethane
EB - Ethyl Benzene
IA- Indoor Air Sample
J - Estimated value
J+ - Results estimated, but may be biased high
MCL - Maximum Contaminant Level
PCE - Tetrachloroethene
RSL - Regional Screening Level
SS - Sub-Slab Sample
TCE - Trichloroethene
VISL - Vapor Intrusion Screening Level
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 10
PHASE II VAPOR INTRUSION
MONITORING RESULTS
(st)suITRAC
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-------
4— 5:1'
\ •
"v;.. a Vr
i!
* /
# ,
i %
ii
__
Legend
Phase I Soil Sample
(May-June 2012)
Phase II Soil Sample
^ (February 2013)
Phase II Soil Sample
(December 2013
and January 2014)
] I Exposure Areas
N
80
Feet
Notes:
CHE - Cherry Street
CLY-Clay Street
CRA - Crawford Street
FRA- Frankfin Street
HER - Herrlinger Way
HOB - Hobart
MAI - Main Street
MUL - Mulberry Street
RAC - Race Street
SB - Soil Boring
SPN - Spinnaker
SS - Soil Sample
STP - St. Patrick Parking Lot
TPD - Troy Police Department
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 11
SOIL EXPOSURE AREAS -
EAST WATER STREET PLUME
ST SulTRAC
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-------
STr'QjY-m
ElsEl
1EPATT04D'
!OEfg?g
¦MWs
|SE^ijps:;0
E a s UWat e riS tFeet-
¦FffumeH
©E^2!
wawa
[gEBgjii
iTRO.VrQ
EPA-101S.
Residential ^
t Plume: ' Sfl
tTRW-P
ijTRQXjQ.
Date Saved: 1H2/2017 9:58:00 AM User: maggie.banh Path: G:\G\1852\145 East Tioy'J^XDVP017-01 \F: n 1 -16-Welis Groundwater_Expo5ui9_021415.mxd
TROY-N
EPA=>23D
¦ ;
Legend
@) Ohio EPA Well
Phase I Rl Well
Phase II Rl Well
© Troy Monitoring Well
© KC Monitoring Well
© MCD Well
Division Line Separating
Up/Down Gradient Plume
Areas
Total Chlorinated VOCs
>100 pg/L (ppb) Plume Area
Total Chlorinated VOCs
<100 |jg/L (ppb) Plume Area
Approximate Area Subject to
I Groundwater Interim Action
(see Figure 5-3)
0 200 400
1 I I I I
Feet
FIGURE 1-16
GROUNDWATER SAMPLE LOCATIONS
AND GROUNDWATER EXPOSURE
AREAS-BOTH PLUMES
Notes:
D - Deep
EPA - US Environmental Protection Agency
GZA - Spinnaker Site/ Kimberly Clark Monitoring Well
I - Intermediate
KMW - Spinnaker Site/ Kimberly Clark Monitoring Well
MCD - Miami Conservation District
OEPA- Ohio Environmental Protection Agency
S - Shallow
I T - Miami Conservancy District Monitoring Well
TROY - City of Troy Monitoring Well
| VOCs - Volatile Organic Compounds
|jg/L - Micrograms per liter
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 12
GROUNDWATER EXPOSURE AREAS
ST SulTRAC
-------
Legend
aP)- Proposed Performance Monitoring Well
© Ohio EPA Well
Phase I Rl Well
Phase II Rl Well
© Troy Monitoring Well
© KC Monitoring Well
© MCD Well
® Geoprobe Location
HRSC Groundwater Profiling
VAS Location
Conceptual Injection and/or
Extraction Well Locations
I'1 , ^ I Targeted Treatment Area
Css Estimated Area for Sub-slab
_!¦ Depressurization Systems
Total Chlorinated VOCs
5 (ppb)
— 1,000 (ppb)
« 500 (ppb)
100 (ppb)
Notes:
Injection, extraction and performance monitoring well
locations are conceptual - actual numbers and locations
will be determined during the remedial design.
Total concentration is the sum of PCE, TCE.
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DCE - cis-1,2-Dichloroethene
D - Deep
EPA - US Environmental Protection Agency
ETCA - East Troy Contaminated Aquifer
GZA- Spinnaker Site/ Kimberly Clark Monitoring Well
KC - Kimberly Clark
KMW - Spinnaker Site/ Kimberly Clark Monitoring Well
MCD - Miami Conservation District
MCL - Maximum Contaminant Level
MOR - Morehead Street
ND - Not detected
OEPA- Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
T - Miami Conservancy District Monitoring Well
TCE - Trichloroethene
VAS - Vertical Aquifer Sample
VC - Vinyl Chloride
VI - Vapor Intrusion
VOC - Volatile Organic Compound
WAL - Walnut Street
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 13
GROUNDWATER TREATMENT
ZONES - RESIDENTIAL PLUME
SOURCE AREA
ST SulTRAC
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-------
Phase I Soil Sample
(May-June 2012)
Phase II Soil Sample
(February 2013)
Phase II Soil Sample
(December 2013
arid January 2014)
Exposure Areas
Estimated area of soil
exceeding PRGs to
15 feet deep
Estimated area of soil
exceeding PRGs to 8
feet deep
Estimated area of soil
exceeding PRGs to 6
feet deep
Notes:
CHE - Cherry Street
CLY - Clay Street
COC - Contaminant of concern
CRA - Crawford Street
FRA - Franklin Street
HER - Herrlinger Way
HOB - Hobart
MAI - Main Street
MUL - Mulberry Street
PRG - Preliminary Remediation Goal
based on RAOs for the interim action
RAC - Race Street
RAO - Regional Action Objectives
SB - Soil Boring
SPN - Spinnaker
SS - Soil Sample
STP - St. Patrick Parking Lot
TPD - Troy Police Department
50
Feet
100
D
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 14
SOIL ALTERNATIVE S-2
PROPOSED EXCAVATION AREAS
ST SulTRAC
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-------
Legend
x, Phase I Soil Sample
V (May-June 2012)
/x Phase II Soil Sample
^ (February 2013)
~ Phase II Soil Sample (December
2013 and January 2014)
Exposure Areas
Proposed Area of Asphalt Cap
Assumed Area of Excavation
(area exceeding PRCs)
Notes:
CHE - Cherry Street
CLY - Clay Street
COC - Contaminant of concern
CRA- Crawford Street
FRA- Franklin Street
HER - Herrlinger Way
HOB - Hobart
MAI - Main Street
MUL - Mulberry Street
PRG - Preliminary Remediation Goal
based on RAOs for the interim action
RAC - Race Street
RAO - Regional Action Objectives
SB - Soil Boring
SPN - Spinnaker
SS - Soil Sample
STP - St. Patrick Parking Lot
TPD - Troy Police Department
50
Feet
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 15
SOIL ALTERNATIVE S-3
PROPOSED SOIL EXCAVATION
AND ASPHALT CAP AREAS
STl SuITRAC
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-------
Legend
-(P)- Conceptual Performance Monitoring Well
@ Ohio EPA Well
Phase I Rl Well
Phase II Rl Well
© Troy Monitoring Well
0 KC Monitoring Well
© MCD Well
© Geoprobe Location
>5 HRSC Groundwater Profiling
W VAS Location
Conceptual Injection and/or
Extraction Well Locations
Total Chlorinated VOCs
—— 5 (ppb)
1 — 1,000 (ppb)
— 500 (ppb)
100 (ppb)
Notes:
Injection, extraction and performance monitoring wells
depicted are conceptual; actual locations and numbers
will be determined during the remedial design.
Total concentration is the sum of PCE, TCE.
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DCE - cis-1,2-Dichloroethene
D - Deep
EPA - US Environmental Protection Agency
GZA- Spinnaker Site/ Kimberly Clark Monitoring Well
ETCA - East Troy Contaminated Aquifer
KC - Kimberly Clark
KMW - Spinnaker Site/ Kimberly Clark Monitoring Weil
MCD - Miami Conservation District
MCL - Maximum Contaminant Level
MOR - Morehead Street
ND - Not detected
OEPA - Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
T - Miami Conservancy District Monitoring Well
TCE - Trichloroethene
VAS - Vertical Aquifer Sample
VC - Vinyl Chloride
VOC - Volatile Organic Compound
WAL-Walnut Street
100
Feet
200
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 16
ALTERNATIVES RGW-2A, RGW-2B
AND RGW-2C
CONCEPTUAL LAYOUT
ST SulTRAC
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-------
Legend
Ohio EPA Well
Phase I Rl Well
Geoprobe Location
HRSC Groundwater Profiling
Direction of Groundwater Flow
_ _ Former Building Footprint - Prior structures
\ located in PCE plume source area, now
t covered by church addition
Conceptual area for amendment injection
and groundwater extraction wells
~ Conceptual area for amendment injection
with clean water
Total Chlorinated VOCs
5 (ppb)
1,000 (ppb)
500 (ppb)
100 (ppb)
1. Enhanced reductive dechlorination assumed to deliver
amendments to targeted treatment zones via
recirculation, with injection and extraction wells used
to recirculate groundwater,
2. Clean water supply well would be located -200 feet
from the process equipment
Total concentration is the sum of PCE, TCE,
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DCE - cis-1,2-Dichloroethene
D - Deep
EPA - US Environmental Protection Agency
ERD - Enhanced Reductive Dechlorination
ND - Not detected
OEPA- Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
VAS - Vertical Aquifer Sample
VOC - Volatile Organic Compound
WAL- Walnut Stree
50
Feet
100
~
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 17
ALTERNATIVE RGW-2A (ERD) AND
RGW-2B (ISCR) ZONE A
CONCEPTUAL LAYOUT
ST SulTRAC
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-------
Legend
Ohio EPA Well
® Phase I Rl Well
© Geoprobe Location
~5 HRSC Groundwater Profiling
Direction of Groundwater Flow
C„, _ _ Former Building Footprint - Prior structures
¦ located in PCE plume source area, now
— — ' covered by church addition
I I Conceptual area for amendment injection
I I with clean water
Total Chlorinated VOCs
5 (ppb)
1,000 (ppb)
500 (ppb)
100 (ppb)
1. In-situ chemical oxidation assumed to deliver
amendments to targeted treatment zones via
injection only.
2, Clean water supply well would be located ~200 feet
from the process equipment.
Total concentration is the sum of PCE, TCE,
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DCE - cis-1,2-Dichloroethene
D- Deep
EPA- US Environmental Protection Agency
ISCO - In Situ Chemical Oxidation
ND - Not detected
OEPA- Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
VAS - Vertical Aquifer Sample
VOC - Volatile Organic Compound
WAL-Walnut Stree
50
Feet
100
~
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 18
ALTERNATIVE RGW-2C: ISCO
ZONE A CONCEPTUAL LAYOUT
ST SulTRAC
Easl T ro'/'iMXD\20"i 7^r\Fig&-7-ISCO-ZoneACoi
-------
Legend
Proposed Performance Monitoring Well
© Ohio EPA Well
Phase I Rl Well
^ Phase II Rl Well
® Troy Monitoring Well
© KC Monitoring Well
© MCD Well
© Geoprobe Location
C4 HRSC Groundwater Profiling
V VAS Location
Conceptual Injection and/or
Extraction Well Locations
Targeted Treatment Area
|9HH Estimated Area for Sub-slab
I—Depressurization Systems
Total Chlorinated VOCs
5 (ppb)
<— 1,000 (ppb)
—— 500 (ppb)
100 (ppb)
Notes:
Injection, extraction and performance monitoring well
locations are conceptual - actual numbers and locations
will be determined during the remedial design.
Total concentration is the sum of PCE, TCE.
cis-1,2-DCE, and VC.
BW - Soil Boring - Groundwater
cis-1,2-DCE - cis-1,2-Dichloroethene
D - Deep
EPA- US Environmental Protection Agency
ETCA - East Troy Contaminated Aquifer
GZA - Spinnaker Site/ Kimberly Clark Monitoring Well
KC - Kimberly Clark
KMW - Spinnaker Site/ Kimberly Clark Monitoring Well
MCD - Miami Conservation District
MCL - Maximum Contaminant Level
MOR - Morehead Street
N D - Not detected
OEPA- Ohio Environmental Protection Agency
PCE - Tetrachloroethene
ppb - Parts per billion
S - Shallow
T - Miami Conservancy District Monitoring Well
TCE - Trichloroethene
VAS - Vertical Aquifer Sample
VC - Vinyl Chloride
VI - Vapor Intrusion
VOC - Volatile Organic Compound
WAL-Wdlnul Street
EAST TROY CONTAMINATED
AQUIFER SITE
TROY, OHIO
FIGURE 19
PROPOSED VI
MITIGATION AREA
ST SulTRAC
-------
APPENDICES
Appendix A - Administrative Record Index
Appendix B - State Concurrence Letter
Appendix C - Cost Estimate for Selected Interim Remedy
55
-------
Appendix A
V< Ci'.'O
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
REMEDIAL ACTION
ADMINISTRATIVE RECORD
FOR THE
EAST TROY CONTAMINATED AQUIFER
TROY, MIAMI COUNTY, OHIO
UPDATE I
JUNE 2 5,2018
SEMS 10: 941241
NO.
SEMS IP DATE
AUTHOR
RECIPIENT
TITLE/DESCRIPTION
PAGES
309029 9/8704
Martin. S., OH Hobart, C., Hobart Letter Re: Hobart Cabinet Co Soil
EPA Cabinet Co. Sampling Results
65
927975 10/18/06
File
File
EPA Press Release Re: EPA
Hosts Public Meeting on Troy,
Ohio Vapor Investigation. Oct.
25. 6 PM
42773 0 10/22/06 ¦ File
269584 5/16/07 U.S. EPA
File
Public
News Article Re; Pollution
Meeting Scheduled
Administrative Record Site Index ¦
East Troy Contaminated Aquifer -
Original - Removal Action
282053 6/12/07
296371 9/19/07
927974 9/3/08
Renninger, S., U.S. Distribution List Pollution Report (POLREP) - # 1
EPA
U.S. EPA File News Release - EPA Proposes
East Troy, Ohio, Site for
Superfund National Priorities List
File File EPA Press Release Re: US EPA
Adds East Troy Site to Superfund
List. Proposes Two Ohio and One
Indiana Site for List
435616 2/11/09
Renninger, S., U.S. File
EPA
Pollution Report (POLREP) - #2
Final POLREP
941884 6/24/09
Sultrac
U.S. EPA (REDACTED) Work Plan -
Remedial Investigation/Feasibility
Study (RI/PS)
24
10 405434
9/21/09
U.S. EPA File
Agenda: EPA/State Meeting with 8
City of Troy Officials
-------
NO.
i !
12
13
14
15
16
17
18
19
20
21
22
S'EMS I'D DATE
AUTHOR
RECIPIENT TLTLE/DESCR1PTIGN
PAGES
920657
444067
444069
9/21/09
U.S. EPA
1/20/10 File
1/27/10
444072 7/14/10
File
File
File
File
File
File
Presentation - Meeting With City 14
Of Troy
Revised Sampling and Analysis 390
Plan (SAP) - (Field Sampling
Plan and QAPP) - Rev.1
Sultrac Letter Re: Summary of 27
Revisions and Responses to
Comments - Revised Sampling
and Analysis Plan (SAP) - Field
Sampling Plan (FSP)
Phase I Quality Assurance Project 144
Plan
90011;
8/1 J/J 0 File
Hie
900112 8/11/10
396670
4/22/11
941885 8/1 111
908334 9/1/11
File
ATSDR & OH
Dept. of Health
Sultrac
File
File
rile
U.S. EPA
File
Sultrac - Remedial Action 255
Contract 2 For Remedial
Enforcement Oversight & Non-
Time Critical Removal Activities -
Attachment A: Phase I Field
Sampling Plan (FSP) - Revision
3.0
Sultrac - Remedial Action 143
Contract 2 for Remedial
Enforcement Oversight & Non-
Tirne-Critical Removal Activities -
Attachment B: Phase 1 Quality
Assurance Project Plan (QAPP) -
Revision 3.0
(Final Release) - Public Health 58
Assessment
(REDACTED) Work Plan - 32
Remedial Investigation/Feasibility
Study (RI/FS) (Revised)
Mailing List for Fact Sheet 1
(Redacted)
920658
432962
414979
10/1/11
} 0/5/11
10/12/1]
U.S. EPA
Koiak. S., U.S.
EPA
Dougherty. K,,
Weston Solutions
File
Resident
Fact Sheet - EPA Checking for
Possible Vapor Problems
Letter Requesting Access for VI
Sampling
De Blasio, D., U.S. Letter re: Advertisement of Public
EPA ' Meeting
-------
NO- SEMS ID DATE
AUTHOR
RE CI PI ENT T1TLE/DESCR1PTIQN
PAGES
423781 10/19/11 File
Hie
Community Meeting Agenda •
10/19/11
24
423778 10/21/11
Middle Great Shear,. S . U.S.
Miami River EPA
Watershed Alliance
Email re: Request for Copy of
PowerPoint Presentation
423783 10/21/1!
Troy Daily News File
inc.
423782 10/24/11 Piqua Daily Call File
Newspaper Article - Testing
Shows Contamination Outside
Sire
Newspaper Article - Chemical
Beneath Sections Of Troy
27 443990 12/9/11
28 432964 12/14/11
29 901129 1/28/12
30 906243 7/12/13
File
Fill
497974 8/9/13
913645 9/6/13
33 913642 9/13/13
35 475196 11/25/12
Kolak. S,. U.S. Resident
EPA
Kolak, S., U.S. Watterworth, R.,
EPA OH EPA
Sampling and Analysis Plan 132
Addendum: Vapor Intrusion
Monitoring Program
Letter Requesting Access for VI 2
Sampling
Email re: Revised Pages for Field 5
Sampling Plan (FSP) (W/
Attachments)
Phase J .Investigation Summary 71
and Proposed Phase 11
.Investigation Activities Technical
M emorandum W/Transm itta 1
Letter
Smith, M., OH Kolak. S., U.S. Email re: OEPA Comments on
EPA EPA Phase II Investigation Summary
Technical Memo/Proposed Phase
111 Remedial Investigation
Activities
Montfort, G..
Sultrac
Montfort, G.,
Sultrac
34 913640 11/6/13 Sulrac
Kolak. S,U.S,
EPA
Kolak. S.; U.S.
EPA
Montfort, G., Kolak, S., .U.S.
Sultrac EPA
U.S. EPA
Hedman, S.. U.S. Upton, F,, U.S.
EPA House of
Representatives
Phase II Investigation Summary 57
Technical .Memorandum (.Revised
Final)
Membrane Interface Probe 48
Investigation Sampling Plan
Expanded Phase 11 Field 155
Sampling Plan
Letter re: Response to 11 /(> 1/13 16
US House of Representatives
Letter Regarding Constituents'
Concerns
-------
36
37
38
39
40
4 J
42
43
44
45
46
4?
SEMSID DATE
482776 12/3/13
481491 10/7/J 4
487337 12/26/14
915515 1/21/15
918065 1/21/15
927973 1/21/15
489096 3/27/15
489095 5/13/15
489097 8/21/15
501707 11/10/15
4891 13 1/12/16
AUTHOR RECIPIENT TITLB/IXESCRSPTIO.N PAGES
File File Oh EPA Comments on Phase H 2
Expanded Sampling & Analysis
Plan. Map Investigation Results.
Summary of Proposed Revised
Sampling Locations
Smith, M., OH Kolak, S..U.S. Letter re: Ohio EPA Review of 6
EPA EPA Draft Remedial Investigation
Report - Comments on the Sultrac
RI Report
Smith. M., OH Kolak, S., U.S. Letter re: Comments on Final 6
EPA EPA Remedial investigation Report &
Risk Assessment
Sulrac U.S. EPA Final Remedial Investigation 1
Report - Appendix M - R
attachments (Zip File)
Sulrac U.S. EPA [Redacted] Final Remedial 338
Investigation Report - Text.
Figures, Tables
Sulrac U.S. EPA Final Remedial Investigation 1
Report - Appendix A-L Zip File)
Smith, M., OH Kolak, S., U.S. Letter re: Ohio EPA Review: 28
EPA EPA Draft Remedial Alternatives
Screening Technical Memo, Feb
23,2015 (W/ Enclosure)
Montfort. G., Kolak, S., U.S. Letter re: Response to Ohio EPA
Sultrac EPA Comments on the Draft Remedial
Alternatives Screening Technical
Memo (W/ Enclosure &
Appendix B)
17
Smith, M.. OH Kolak, S., U.S.
EPA EPA
Montfort, G., Tetra File
Tech. Inc.
Letter re: Ohio EPA Review:
Draft Remedial Alternatives
Screening Technical Memo, Feb
23.201.5 (W/ Enclosure)
Email re: Fw: Call - Diagrams of
Drv Cleaner Docx
Montfort. G., Tetra Kolak, S., U.S.
Tech, Inc. EPA
Email re: Basis for No SVE
Testing Under Church
489123 1/28/16
Adams, M.. OH Kolak, S„ U.S.
EPA EPA
Email re: OEPA VI Sampling -
Church
-------
NO,
48
49
50
5)
52
53
5?
58
59
60
61
62
63
SEY1S ID DATE
AUTHOR
RECIPIENT
TITLE/DESCRIPTION
PACES
489124 1/29/16
4891.10 2/1/16
459098 2/5/16
489106 3/2/16
937733 3/16/16
937735 5/2/16
509760 5/3/16
518 i 07 7/11/16
546584
933505
9/28/16
1/1/1 /
Adams, JVC OH
EPA
Kolak, S., U.S.
EPA
Adams, .VS.. OH
EPA
Kotak, S., U.S.
EPA
Kotak, S„ U.S.
EPA
Adams, M,, OH
EPA
Adams, M,. OH
EPA
Adams, ]v!., OH
EPA
Adams. M., OH
EPA
U.S. EPA
Kotak, 5, U.S.
EPA
Adams, M.. OH
EPA
Kotak. U.S.
EPA
File
Kaster,First
Presbyterian
Church
Kaster. L, First
Presbyterian
Church
Kotak, S., U.S.
EPA
Kotak, S„ U.S.
EPA
Kotak, S.. U.S.
EPA
File
Email re: Moisture Barrier - VI
Sub-Slab Sampling
Email re: Moisture Barrier - VI
Sub-Si ab Sampling
Letter re: Ohio EPA Concerns
Regarding Proposed Interim
Action & Focused Feasibility
Study Approach
Draft Agenda - EPA/OEPA
Meeting - .Draft FS/lnterim Rod
[Redacted] Letter re: Request for
Consent to Access - First
Presbyterian Church (Signed
Access Agreement Attached)
[Redacted] Letter re: Indoor Air
& Sub-Slab Vapor Sample
Results - First Presbyterian
Church, 20 S. Walnut St.
Letter re: Review Summary of
Proposed Remedial Action
Objectives for Focused Feasibility
Study-
Letter re: Oh EPA Review Input
Values of Site-Specific Soil
Leaching Calculation for Focused
Feasibility Study-
Letter re: OH EPA Request for
Administrative Discussion on
Changes to RI/FS Approach
Community involvement Plan -
2017
134
84
546578
937465
937736
3/17/17
4/5/17
5/17/17
Adams, M.., OH
EPA.
U.S. EPA
Montfort, G„
Sultrac
Kolak. S., U.S.
EPA
File
Kolak. S., U.S.
EPA
Review of Draft Focused
Feasibility Study Report
[Redacted] Alternatives Array
Review Panel Presentation
[Redacted] Responses to
Comments,'Proposed Revisions,
Draft Focused feasibility Study
Report (Rev 0)
30
-------
NO. SEMS IP DATE AUTHOR RECIPIENT
64 546579 7/12/17 Adams, M- OH Koiak. S..U.S.
EPA EPA
65 546580 7/26/17 Koiak, S„ 'U.S. Adams, M, OH
EPA EPA
66 937462 8/21/17 File File
67 937463 8/23/17 File File
68 545510 9/28/17 Adams. M, OH Koiak, S., U.S.
EPA EPA
69 545511 10/5/37 Koiak. S„ U.S. Adams,M., OH
EPA EPA
70 2000451 30/5/17 Sultrac File
71 516340 5/15/18 Proffitt, M, OH Koiak, S., U.S.
EPA EPA
72 941242 6/3/18 U.S. EPA Public
73 423779 Undated File File
"4 516346 6/12/18 U.S. EPA Public
TiTLE/DBSCR) P Tl ON PAGES
Review of Response 10 Comment 2
on Draft Focused Feasibility
Study Report
US EPA Response to OH EPA 4
Comments
[Redacted] Email Correspondence 4
re: East Troy Contaminated
Aquifer - Question On Response
JO Comment 1
[Redacted] Email Correspondence 3
re: East Troy Contaminated
Aquifer - Question On Response
to Comment 1
Memo re: Review & I
Concurrence, Final Focused
Feasibility Study. 08/31/17
Letter re: Approval of Final 1
Focused Feasibility Study Report
Final Focused Feasibility Study 277
Report-
Letter re: Support of Proposed 1
Plan for Interim Source Area
Cleanup at the East Troy
Contaminated Aquifer
Fact Sheet - Proposes Interim 10
Cleanup for Two Areas at Site
EPA Fact Sheet - What You 2
Should Know About Vapor
intrusion
Proposed Plan for Interim Source 53
Area Cleanup East Troy
Contaminated Aquifer Site
(ETCA)
75 941237 6/15/18 Troy Daily News Public
Inc.
EPA Public Comments Period
Begins on a Proposed Interim
Cleanup Plan
1
-------
U.S. ENVIRONMENTAL PROTECTION AGENCY
REMEDIAL ACTION
ADMINISTRATIVE RECORD
FOR THE
EAST TROY CONTAMINATED AQUIFER
TROY, MIAMI COUNTY, OHIO
UPDATE 2
SEPTEMBER, 2018
SEMS ID:
NO.
SEMS ID
DATE
AUTHOR
RECIPIENT
TITLE/DESCRIPTION
PAGES
]
516369
7/1/18
U.S. EPA
Resident
Public Comment Sheet
1
2
516370
7/1/18
Ohio EPA
Public
Public Hearing
8
3
516371
7/24/18
Kimberly-Clark
Corporation
U.S. EPA
Proposed Plan for Interim Source
Area Cleanup
66
4
531517
9/10/18
Butler, C, Ohio
EPA
Ballotti, D., U.S.
EPA
Record of Decision Concurrence
1
5
-
-
Roiak, S, U.S.
EPA
-
Record of Decision (ROD)
-
-------
Appendix B
State Concurrence Letter
-------
0hio
S Ohio Environmental
Protection Agency
September 10, 2018
John R. Kasich, Governor
Mary Taylor, Lt. Governor
Craig W. Butler, Director
Douglas Ballotti, Acting Director
Superfund Division
U.S. EPA, Region 5
77 West Jackson Boulevard
Chicago, IL 60604-3590
Troy Well Field Unknown Source
Remediation Response
Project records
Remedial Response
Miami County
555001353010
RE: Record of Decision Concurrence
East Troy Contaminated Aquifer Site, Troy, Miami County, Ohio
Dear Mr. Ballotti:
The Ohio Environmental Protection Agency has reviewed the Interim Record of Decision
for Source Area Cleanup at the East Troy Contaminated Aquifer Site. Ohio EPA concurs
with U.S. EPA's selected interim remedy, which consists of the following components:
1. Soil Alternative S-2 - Excavation of soils with off-site disposal at the former Hobart
Cabinet and Spinnaker Coatings properties to address soil sources affecting the
East Water Street Plume.
2. Ground water Alternative RGW-2C - In-situ treatment of ground water using
chemical oxidation to reduce net ground water contamination within the Residential
Plume.
3. Vapor Alternative VI-2 - Installation of sub-slab depressurization systems beneath
occupied structures over the Residential Plume.
We look forward to working with U.S. EPA on the successful design and implementation
of the selected interim remedy. If you have any questions, please contact site coordinator
Scott Glum at (937) 285-6065, or you may contact me at (614) 902-4232.
Sincerely,
Craig W. Butler
Director
ec: Scott Glum, Site Coordinator, DERR SWDO
Mike Starkey, Manager, DERR SWDO
Mark Rickrich, ARCA Section Manager, DERR CO
50 West Town Street « Suite 700 • P.O. Box 1049 • Columbus, OH 43216-1049
epa.ohio.gov • (614) 644-3020 • (614) 644-3184 (fax)
-------
Appendix C
Cost Estimate far Selected Interim Remedy
-------
SOIL ALTERNATIVE S-2
SOIL EXCAVATION AND OFF-SITE DISPOSAL
CAPITAL COSTS
Unit Price
Item
Description
Quantity
Unit
(Incl. O&P)
Total Cost
Preparation
1
Engineering Design/Agency approvals/Access Agreements/Permits
1
LS
$ S0.000.00
S
80,000
2
Construction Contractor Mobilization/Demobilization, Site Preparation. Permits and Submittals
1
LS
$ 50,000.00
$ 50,000
Preparation Subtotal
$
130,000
Implementation
3
Soil Excavation, Transportation and Disposal - Hobart - non-hazardous waste
9,839.70
CY
S 60.00
$
590,382
4
Soil Excavation, Transportation and Disposal - Hobart - hazardous waste
1,093.30
CY
$ 175.00
$ 191,328
5
Soil Excavation, Transportation and Disposal - Spinnaker - non-hazardous waste
882
CY
s
60.00
$ 52,920
6
Soil Excavation, Transportation and Disposal - Spinnaker -hazardous waste
98
CY
s
175.00
$ 17,150
7
Shoring at Hobart (wood sheeting with wales and braces - drive, extract and salvage - 16 feet)
9,456
SF
$
15.84
$ 149,783
8
Shoring at Hobart (wood sheeting with wales and braces - drive, extract and salvage- 10 feet)
1,670
SF
$
12.90
$ 21.543
9
Backfilling at Hobart (stone)
9,110
CY
$
35.00
$
318,850
10
Backfilling at Spinnaker (stone)-
815
CY
$
35.00
$
28,525
11
Replace asphalt surface at Spinnaker - S-inches base course and 6-inch asphalt
3,175
SF
s
35.00
S
111,125
12
Surveyor
1
LS
s
5,000.00
s
5,000
Implementation Subtotal
$
1,486,606
Confirmation Sampling
13
Confirmation Soil Sampling at Hobart (includes labor, sampling equipment, shipping and laboratory costs)
86
ea
s
200.00
$
17,200
14
Confirmation Soil Sampling at Spinnaker (includes labor, sampling equipment, shipping and laboratory costs)
18
ea
s
200.00
$
3,600
Confirmation Sampling Subtotal
s
20,S00
Site Restoration
15
Site Restoration and Cleanup at Hobart
1
LS
s
5,000.00
$
5,000
16
Site Restoration and Cleanup at Spinnaker
1
LS
$
5,000.00
s
5,000
Site Restoration Subtotal
s
10,000
Construction Subtotal __ S 1.647,406
Construction Contractor Bonds
2%
$
32,948
Project management and construction oversight
5%
$
82,370
Construction Subtotal Plus Contractor Bonds, Project Management, and Oversight
S
1,762,724
CAPITAL COST SUBTOTAL S 1,762,724
INSTITUTIONAL CONTROLS COSTS
Unit Price
Item
Description
Quantity
Unit
(Incl. O&P)
Total Cost
Institutional Controls
None
0
hr
s
S
Institutional Controls Subtotal
S
O&M COSTS
Item Description
Unit Price
Quantity Unit (Incl. O&P) Total Cost
Annual Maintenance
1 |None 1 0.0 | EA | S
$
Maintenance Subtotal
$
Annual Monitoring
2 |None 1 0.0 | EA | $
$
Monitoring Subtotal
S
Annual Operation and Maintenance Subtotal
s
ALTERNATIVE S-2 SOIL EXCAVATION AND OFF-SITE DISPOSAL COST SUMMARY
Description
Subtotal
Construction
S 1,762,724
Institutional Controls
S
Operation and Maintenance
S
Continsency
1 30% 1
S 528,817 1
| Total (Rounded)
| S 2.290,000 |
-------
GROUNDWATER ALTERNATIVE RGW-2C
CAPITAL COSTS
Item
Description
Quantity
Unit
Unit Price (Incl. O&P)
Total Cost
Wells
1
Injection wells (includes well box, up to 100' TD, nested, 3x) and wellhead
18.0
ea
$
20,397.53
$
367,156
2
Injection wells (includes well box, up to 60' TD, nested, 3x) and wellhead
27.0
ea
$
12.508.69
S
337,735
3
Extraction wells (includes well box, up to 100' TD), wellhead, pumps and motors
1.0
ea
$
23.909.69
S
23,910
4
Extraction wells (includes well box, up to 60' TD), wellhead, pumps and motors
1.0
ea
S 14,886.15
s
14,886
5
Monitoring wells (includes manhole, up to 100' deep)
18.0
ea
$
9,185.64
$
165,342
6
Monitoring wells (includes manhole, up to 60' deep)
12.0
ea
$
5,511.39
$
66,137
Wells subtotal
$
975,166
Piping and Fittings
7
Injection/extraction piping
2,600.0
ft
$ 39.17
S 101,842
8
Gate valves, flow sustaining valves, solenoid valves
46.0
ea
S 1,395.39
$ 64,188
Piping and Fittings subtotal
S 166,030
Earthwork and Paving
9
Trenching, bedding, backfilling, compacting (2' wide x 4' deep)
2,600.0
ft
$ 12.33
S 32,058
10
Asphalt cutting
5,200.0
ft
$ 2.01
S 10,452
11
Install asphalt pavement (HMA, 6" thick)
5.200.0
sf
$ 5.44
$ 28,288
Earthwork and Paving subtotal
$ 70,798
Electrical
12
Electrical service and meter installation
1.0
ea
$ 5,443.84
$
5,444
13
Building wiring and fixtures
600.0
sf
S
6.98
$
4,188
14
Electrical conduit (1.5". power + control)
5,200.0
ft
S
4.04
$
21,008
15
Power wiring (14 AWG, 3 wire)
2,600.0
ft
S
0.50
$
1,300
16
Control wiring (18 AWG. 2 wire)
7.800.0
ft
S
0.50
S
3,900
17
Motor control center
1.0
ea
$
27,016.60
$
27,017
18
SCAD A system (large)
1.0
ea
S
135,083.00
s
135,083
Electrical subtotal
$
197,940
Process Equipment
19
Control building (20' x 30')
600.0
sf
S 17.80
$ 10,680
20
Chemical holding tank (10,000 gal)
1.0
ea
S 11,379.38
$ 11,379
21
Metering pump (1 gpm)
1.0
ea
$ 1,730.41
$ 1,730
22
Bag filter
2.0
ea
S 1,833.08
$ 3,666
Process Equipment subtotal
S 27,455
Remediation Products
23
Sodium permanganate
573.0
ton
$ 5,241.22
$ 3,003,219
24
NA
0.0
-
$
S
25
MA
0.0
-
$
$
Remediation Products subtotal
$ 3,003,219
Construction Support
26
Utility surveying
4.0
day-
S 3,377.08
$ 13,508
27
Land survey (progress)
50.0
day
S 1,702.05
$ 85.103
28
Land survey (as-built)
5.0
day
S 1.702.05
$ 8,510
Construction Support subtotal
S 107,121
Construction Subtotal
$ 4,547,729
Construction Subtotal
$
4,547,729
29
Construction Contractor Mobilization/Demobilization, Site Preparation and Submittals
10%
$
454,773
30
Project management
3.5%
$
159,171
31
Construction oversight
15%
$
682,159
32
Fate and transport modeling
1%
S
45.477
33
Engineering design
9%
s
409,296
Construction Subtotal plus additional above costs
$
6,298,605
INSTITUTIONAL COINTROLS COSTS
Item
Description
Quantity
Unit
Unit Price (Incl. O&P)
Total Cost
33
Prepare LUC Implementation Plan (mid-level staff with senior review)
0
hr
$
$
34
Meetings with agencies (senior staff and attorneys)
0
lir
$
$
Institutional Controls Subtotal
S
-------
GROUNDWATER ALTERNATIVE RGW-2C
PRE DESIGN ACTIVITIES
Item
Description
Quantity
Unit
Unit Price (Incl. O&P)
Total Cost
35
Baseline groundwater monitoring
1.0
ea
$ 51,955.00
$ 51,955
36
Source area investigation
1.0
ea
$ 283,674.30
$ 283,674
37
E Main area investigation
1.0
ea
S 101,312.25
$ 101,312
38
Water supply well siting
1.0
ea
$ 33.770.75
$ 33,771
39
NOD testing
1.0
ea
$ 6,754.15
$ 6,754
40
Pilot test (ROl, flow rate, pressure)
1.0
ea
$ 135,083.00
$ 135,083
Pre-Design Activities Subtotal
$ 612,549
GROUNDWATER MONITORING COSTS
Item
Description
Quantity
Unit
Unit Price (Incl. O&P)
Total Cost
Groundwater Monitoring Event
41
Sampling
50.0
wells
S 1.215.75
S 60,788
42
Field parameters
50.0
ea
$ 33.77
$ 1,689
43
VOCs
58.0
ea
$ 94.56
$ 5,484
44
Dissolved metals
58.0
ea
$ 81.05
$ 4,701
45
Ferrous
58.0
ea
$ 27.02
S 1,567
46
Dissolved gases
58.0
ea
$ 71.59
$ 4,152
47
Dissolved organic carbon
58.0
ea
$ 67.54
S 3,917
48
Monitoring repoit
1.0
ea
S 13,508.30
S 13,508
Groundwater Monitoring Event subtotal
S 95,806
OPERATION AND MAINTENANCE COSTS
Item
Description
Quantity
Unit
Unit Price (Incl. O&P)
Total Cost
O&M and Reporting
49
System operation
12
mo
$ 2,161.33
$ 25,936
50
System maintenance
12
mo
$ 5,403.32
S 64,840
51
Energy cost
33,188
KWH
$ 0.11
$ 3,651
52
Annual monitoring report
1
ea
$ 20,262.45
$ 20,262
53
Proj.Mgmt. | 2hrsAvk |onprojfor | 52 | weeks
104
hr
S 129.89
$ 13,509
O&M and Reporting subtotal
$ 128,198
ALTERNATIVE COST SUMMARY
Description
Subtotal
Construction
$ 6,298,605
Pre-dcsign activities
S 612,549
Institutional Controls
S
Operation, Maintenance and Monitoring (Present Value Analysis Costs-see Table C-2-3A)
$ 2,293,409
| Contingency
1 30% j
$
2,761,369 |
|Total (Rounded)
$
11,966,000 |
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GROUNDWATER ALTERNATIVE RGW-2C
Annual Discount Rate
10-Yr j 7.00% 1
Present Value Analysis
Year
Annual
Discount
Factor2
Operation and Maintenance Costs
30-Yr
Description
Future Cost3
Description
Future Cost3
Present Value
(20X7)
0
1.000
Baseline monitoring
$95,806
$95,806
1
0.935
Quarterly monitoring and system O&M
$511,422
$477,964
2
0.873
Semi-annual monitoring and system O&M
$319,810
$279,334
3
0.816
Semi-annual monitoring and system O&M
$319,810
$261,060
4
0.763
Semi-annual monitoring and system O&M
$319,810
$243,981
5
0.713
Semi-annual monitoring and system O&M
$319,810
Five-Year Review
$25,000
$245,844
6
0.666
Semi-annual monitoring and system O&M
$319,810
$213,103
7
0.623
Semi-annual monitoring and system O&M
$319,810
$199,161
8
0.582
Semi-annual monitoring
$191,612
$111,520
9
0.544
Semi-annual monitoring
$191,612
$104,224
10
0.508
Annual monitoring
$95,806
Five-Year Review
$25,000
$61,412
11
0.475
$0
12
0.444
$0
13
0.415
$0
14
0.388
$0
15
0.362
$0
16
0.339
$0
17
0.317
$0
18
0.296
$0
19
0.277
$0
20
0.258
$0
21
0.242
$0
22
0.226
$0
23
0.211
$0
24
0.197
$0
25
0.184
$0
26
0.172
$0
27
0.161
*
$0
28
0.150
$0
29
0.141
$0
30
0.131
$0
Total Present Value of Periodic Cost $2,293,409
Notes:
1 Annual discount rate = 7% (EPA 540-R-00-G02)
- Annual discount factor= 1 /(1+i)', where i = discount rate (includes inflation and interest) and t = year
3 Current dollar cost of future event
O&M Operations and maintenance
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SOIL VAPOR ALTERNATIVE VI-2
CAPITAL COSTS
Unit Price
Item
Description
Quantity
Unit
(Inch O&P)
Total Cost
Prc-design
i
Pre-design investigation (inspection of up to 156 locations)
1.0
Is
$ 50,000.00
$ 50,000
Pre-design subtotal
S 50,000
Management and Oversight
2
Project management (5 hrAvk for 23 weeks)
115.0
hr
S 125.00
$ 14,375
3
Construction oversight (12 hr/system x 184 systems)
2.208.0
hi-
S 100.00
S 220,800
4
Construction oversight travel (4,000/wk x 23 weeks)
23.0
wk
$ 4,000.00
S 92,000
Management and Oversight subtotal
S 327,175
Testing
5
Post-installation testing (labor for set-up & collection and sample analysis)
184.0
ea
S 1,200.00
S 220,800
Testing subtotal
S 220.800
Svstem Installation
6
Single-family home installation (128 properties x 1 system each)
128.0
ea
$ 1,500.00
$ 192,000
7
Commercial property installation (28 properties x 2 systems each)
56.0
ea
$ 4,000.00
$ 224,000
Svstem Installation subtotal
S 416,000
Site Restoration
8
Site cleanup (184 systems)
184.0
ea
S 200.00
$ 36,800
Site Restoration subtotal
S 36,800
Construction Subtotal
Contractor Mobilization/Demobilization, Site Preparation and Submittals
10%
S
105,078
Engineering design
12%
S
126,093
Construction Subtotal plus additional above costs
S
1,281,946
CAPITAL COST SUBTOTAL
$
1,281,946
O&M COSTS
Item
Description
Quantity
Unit
Unit Price
(Incl. O&P)
Total Cost
Maintenance
1
Routine SSD system maintenance | 184.0 | ea | S 100.00
S 18,400
Maintenance subtotal
S 18,400
Monitoring
2
Indoor air monitoring (labor and sample analysis-1 sample per residential
structure and 2 samples per commercial structure)
184.0
ea
$ 1.200.00
S 220,800
3
Annual monitoring report
1.0
Is
S 5,000.00
$ 5,000
Monitoring subtotal
S 225,800
Inspections
4
Annual system inspections (includes labor - 2 hours per system - and travel)
368.0
hr
$ 125.00
$ 46,000
5
Annual inspection report
1.0
Is
$ 5,000.00
S 5,000
6
Project Management | 2hrs/wk | on project for | 52 | weeks
104.0
hr
$ 125.00
$ 13,000
Inspections subtotal
S 64,000
|Annual Operation and Maintenance Subtotal 1 S 308,200
ALTERNATIVE COST SUMMARY
Description
Subtotal
Construction
S
1,281,946
Operation and Maintenance (15-Year Present Value Analysis Costs-see Table C-3-1 A)
S
2,846,654
1 Contingency | 30% |
s
1,238,580
| Total (Rounded)
S 5,370,000 I
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SOIL VAPOR ALTERNATIVE VI-2
Annual Discount Rate
15-Yr j 7.00% |
Present Value Analysis
Year
Annual
Discount
Factor 2
Operation and Maintenance Costs
30-Yr
Description
Future Cost3
Description
Future Cost3
Present Value
(2017)
0
1.000
$0
1
0.935
SSD SYSTEM O&M
$308,200
$288,037
2
0.873
SSD SYSTEM O&M
$308,200
$269,194
3
0.816
SSD SYSTEM O&M
$308,200
$251,583
4
0.763
SSD SYSTEM O&M
$308,200
$235,124
5
0.713
SSD SYSTEM O&M
$308,200
Five-Year Review
$25,000
$237,567
6
0.666
SSD SYSTEM O&M
$308,200
$205,367
7
0.623
SSD SYSTEM O&M
$308,200
$191,931
8
0.582
SSD SYSTEM O&M
$308,200
$179,375
9
0.544
SSD SYSTEM O&M
$308,200
$167,640
10
0.508
SSD SYSTEM O&M
$308,200
Five-Year Review
$25,000
$169,382
11
0.475
SSD SYSTEM O&M
$308,200
$146,424
12
0.444
SSD SYSTEM O&M
$308,200
$136,844
13
0.415
SSD SYSTEM O&M
$308,200
$127,892
14
0.388
SSD SYSTEM O&M
$308,200
$119,525
15
0.362
SSD SYSTEM O&M
$308,200
Five-Year Review
$25,000
$120,767
Total Present Value of Periodic Cost S2,846,654
Notes:
I Annual discount rate = 7% (EPA 540-R-00-002)
- Annual discount factor = 1 /(1 +i)', where i = discount rale (includes inflation and interest) and t = year
3 Current dol 1 ar cost of future event
O&M Operations and maintenance
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