U. S. EPA Region 10
Final Focused Feasibility Study
Well 12A Superfund Site
Tacoma, Washington
U.S. Environmental Protection Agency Region X
TASK ORDER NO. 014A
April 2, 2009
-------
Contents
Section 1 Introduction
1.1 Report Summary 1-1
1.1.1 Purpose 1-1
1.1.2 Report Organization 1-2
Section 2 Site Characterization
2.1 Site Description and Background 2-1
2.1.1 Site Description 2-1
2.1.2 Site History 2-1
2.1.3 Previous Remedial Actions and Investigations 2-2
2.1.4 Site Geology and Hydrogeology 2-3
2.1.5 Nature and Extent of Contamination 2-4
2.1.5.1 Soil 2-5
2.1.5.2 Groundwater 2-6
2.2 Conceptual Site Model 2-7
2.2.1 Fate and Transport 2-7
2.2.1.1 Contaminants of Concern 2-8
2.2.1.2 Contaminant Transport Pathways and Mass Distribution 2-8
2.2.1.3 Risk Evaluation 2-9
2.2.2 Conceptual Site Model Overview 2-9
Section 3 Identification of Remedial Action Objectives
3.1 Identification of Potential Applicable or Relevant and Appropriate
Requirements 3-1
3.1.1 Definition and Types of ARARs 3-1
3.2 Identification of Potential Treatment Zones and Remediation Boundaries 3-3
3.2.1 Filter Cake and Shallow Impacted Soil 3-3
3.2.2 Deep Vadose Zone Soil and Upper Saturated Zone East of
Time Oil Building 3-4
3.2.3 High Concentration Groundwater 3-4
3.2.4 Low Concentration Groundwater 3-5
3.3 Remedial Action Objectives 3-5
3.3.1 Mass Flux Measurement 3-6
3.4 Identification and Screening of Remedial Technologies and
Process Options 3-11
Section 4 Development and Detailed Evaluation of Remedial Alternatives
4.1 Remedial Alternative Development 4-1
4.2 Detailed Description of Alternatives 4-2
4.2.1 Filter Cake and Shallow Impacted Soil 4-2
4.2.1.1 Alternative FC1 - No Action 4-2
CDM
Well 12A Final FFS April 2009
-------
Table of Contents
4.2.1.2 Alternative FC2 - Institutional Controls 4-3
4.2.1.3 Alternative FC3 - Capping Contaminated Soils in Place 4-3
4.2.1.4 Alternative FC4 - Excavation of Soils (10 Ft Maximum),
Transportation to and Disposal in RCRA Subtitle
C or D Landfill 4-3
4.2.2 Deep Vadose Zone Soil and Upper Saturated Zone East of Time Oil
Building 4-4
4.2.2.1 Alternative SGI - No Action 4-4
4.2.2.2 Alternative SG2 - Institutional Controls 4-4
4.2.2.3 Alternative SG3 - In-situ Thermal Remediation 4-4
4.2.3 High Concentration Groundwater 4-6
4.2.3.1 Alternative HG1 - No Action 4-6
4.2.3.2 Alternative HG2 - Institutional Controls 4-6
4.2.3.3 Alternative HG3 - Extraction and Treatment with GETS 4-7
4.2.3.4 Alternative HG4 - Enhanced Anaerobic Bioremediation 4-7
4.2.3.5 Alternative HG5 - Air Sparging and Soil Vapor Extraction...4-10
4.2.4 Low Concentration Groundwater 4-12
4.2.4.1 Alternative LG1 - No Action 4-12
4.2.4.2 Alternative LG2 - Wellhead Treatment at Well 12A 4-12
4.3 Evaluation Criteria 4-14
4.4 Individual Analysis of Alternatives 4-16
4.4.1 Filter Cake and Shallow Impacted Soil 4-16
4.4.1.1 Alternative FC1 - No Action 4-16
4.4.1.2 Alternative FC2 - Institutional Controls 4-17
4.4.1.3 Alternative FC3 - Capping Contaminated Soils in Place 4-18
4.4.1.4 Alternative FC4 - Excavation of Soils, Transportation to
and Disposal in RCRA Subtitle C or D Landfill 4-19
4.4.2 Deep Soil and High Concentration Groundwater East of Time Oil
Building 4-20
4.4.2.1 Alternative SGI - No Action 4-20
4.4.2.2 Alternative SG2 - Institutional Controls 4-21
4.4.2.3 Alternative SG3 - In-situ Thermal Remediation 4-22
4.4.3 High Concentration Groundwater 4-24
4.4.3.1 Alternative HG1 - No Action 4-24
4.4.3.2 Alternative HG2 - Institutional Controls 4-24
4.4.3.3 Alternative HG3 - Extraction and Treatment with GETS 4-25
4.4.3.4 Alternative HG4 - Enhanced Anaerobic Bioremediation 4-26
4.4.3.5 Alternative HG5 - Air Sparging and Soil Vapor Extraction...4-28
4.4.4 Low Concentration Groundwater 4-30
4.4.4.1 Alternative LG1 - No Action 4-30
4.4.4.2 Alternative LG2 - Wellhead Treatment at Well 12A 4-30
Section 5 Comparative Analysis of Alternatives
5.1 Filter Cake and Shallow Impacted Soils 5-1
5.1.1 Overall Protection of Human Health and the Environment 5-1
5.1.2 Compliance with ARARs 5-2
5.1.3 Long-Term Effectiveness and Permanence 5-2
5.1.4 Reduction of Toxicity, Mobility, or Volume through Treatment 5-3
COM
Well 12A Final FFS April 2009
-------
Table of Contents
5.1.5 Short-T erm Effectiveness 5-3
5.1.6 Implementability 5-4
5.1.7 Cost 5-4
5.2 Deep Vadose Zone Soil and Upper Saturated Zone East of the Time Oil
Building 5-5
5.2.1 Overall Protection of Human Health and the Environment 5-5
5.2.2 Compliance with ARARs 5-5
5.2.3 Long-Term Effectiveness and Permanence 5-6
5.2.4 Reduction of Toxicity, Mobility, or Volume through Treatment 5-6
5.2.5 Short-Term Effectiveness 5-6
5.2.6 Implementability 5-7
5.2.7 Cost 5-7
5.3 High Concentration Groundwater 5-8
5.3.1 Overall Protection of Human Health and the Environment 5-8
5.3.2 Compliance with ARARs 5-8
5.3.3 Long-Term Effectiveness and Permanence 5-9
5.3.4 Reduction of Toxicity, Mobility, or Volume through Treatment 5-10
5.3.5 Short-Term Effectiveness 5-10
5.3.6 Implementability 5-11
5.3.7 Cost 5-11
5.4 Low Concentration Groundwater 5-12
5.4.1 Overall Protection of Human Health and the Environment 5-12
5.4.2 Compliance with ARARs 5-12
5.4.3 Long-Term Effectiveness and Permanence 5-13
5.4.4 Reduction of Toxicity, Mobility, or Volume through Treatment 5-13
5.4.5 Short-Term Effectiveness 5-13
5.4.6 Implementability 5-14
5.4.7 Cost 5-14
5.5 Alternative Groups 5-14
5.6 Long Term Decision Guidelines 5-15
Section 6 References
COM
Well 12A Final FFS April 2009
-------
Table of Contents
Figures
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
2-9
2-10
2-11
2-12
2-13
2-14
2-15
2-16
2-17
3-1
3-2
3-3
3-4
3-5
4-1
4-2
4-3
Tables
2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8
3-1
3-2
3-3
4-1
5-1
5-2
Site Location Map
Area Map and Well Locations
Site Map and Well Locations
Groundwater Flow Gradients and Capture Zone Extent
Tetrachlorethylene in Soil
Trichloroethylene in Soil
Cis-l,2-Dichloroethylene in Soil
Trans-l,2-Dichloroethylene in Soil
Tetrachloroethane in Soil
Trichloroethylene in Soil - Three Dimensional View
1,1,2,2-Tetrachloroethane in Soil - Three Dimensional View
Trichloroethylene in Groundwater
Cis-l,2-Dichloroethylene in Groundwater
1,1,2,2-T etrach loroetha ne in Groundwater
1,4-Dioxane in Groundwater - February/March 2008
Monitored Natural Attenuation Evaluation Summary - June 2008
Groundwater Contamination and Flow Gradients
Proposed Treatment Zones in Soil
Proposed Treatment Zones in High Concentration and Low Concentration
Groundwater Plume
Compilation of the Proposed Treatment Zones
Groundwater Contamination and Flow Gradients with Flux Measurement Line
Intrinsic Bioremediation Parameters and Flux Measurement Location
Excavation, Capping and In-situ Thermal Remediation Alternatives
Enhanced Anaerobic Bioremediation Alternative
Air Sparging and Soil Vapor Extraction with Enhanced Bioremediation
Model Toxics Control Act Soil Cleanup Level Comparison
Calculation of Soil Cleanup Levels (Ingestion Exposure Route) - Method B
Calculation of Soil Cleanup Levels (Ingestion and Dermal Exposure Rates) -
Modified B
Soil to Groundwater Pathway Cleanup Level - Method B
Well 12A Analytical Data from February/March 2008
Contaminant Volume and Mass Estimate - March 2008
Contaminant Volume and Mass Estimate - Soil Plume
Comparison of Contaminant Mass Above and Below Water Table
Chemical-Specific ARARs/TBCs
Location-Specific ARARs/TBCs
Action-Specific ARARs/TBCs
Summary of Comparative Analysis Alternatives
Summary of Comparative Analysis of Alternatives
Alternate Groups and Cost Estimates
CDM
Well 12A Final FFS April 2009
-------
Table of Contents
Appendices
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Contaminant Source Strength and Timing and Sensitivity Analysis
Memorandum
Monitored Natural Attenuation Evaluation Memorandum
Johnson and Ettinger Screening Results Memorandum
Hydrogeological Analysis
Table 1 of 2 - Screening of Technologies and Process Options
Applicable to Soil
Table 2 of 2 - Screening of Technologies and Process Options
Applicable to Groundwater
Cost Estimates
CDM
Well 12A Final FFS April 2009
V
-------
Section 1
Introduction
This Focused Feasibility Study (FFS) has been prepared by Parametrix/CDM Federal
Programs Corporation (CDM) for the South Tacoma Channel/Well 12A Superfund
Site (Well 12A site or site), located in Tacoma, Washington. The document has been
prepared for the United States Environmental Protection Agency (EPA) Region X
under Contract No. 68-S7-03-04 (R-10 AES) Task Order 014A. The FFS was prepared
in accordance with the Work Plan Amendment No. 7 Rev. 1 dated January 21, 2009,
systematic planning meetings held on March 24, 2008; August 7, 2008; and October 1,
2008 and communications between EPA and CDM.
The purpose of this FFS is to support the selection of a remedial alternative for soil
and groundwater that will be documented in a Record of Decision (ROD)
Amendment or other administrative vehicle (e.g., Explanation of Significant
Difference). A ROD Amendment has been assumed for this FFS for discussion
purposes, but the FFS is applicable for any vehicle chosen. In accordance with RODs
for Commencement Bay/South Tacoma Channel (EPA 1983) and South Tacoma
Channel - Well 12A (EPA 1985), groundwater treatment at Well 12A and
groundwater treatment at the Time Oil property using a groundwater extraction and
treatment system (GETS) is ongoing. Other completed removal/remedial actions
include excavation and disposal of contaminated soil/filter cake and operation of a
soil vapor extraction system (SVE). However, contaminant mass still remains in the
soil and groundwater. Therefore, EPA has elected to perform this FFS to select a
feasible and cost-effective remedial alternative that aggressively destroys contaminant
mass and protects public health and the environment from the potential risks posed
by soil and groundwater contamination.
1.1 Report Summary
The summary provides a description of the objectives and content of the report.
1.1.1 Purpose
The FFS approach involves evaluating alternatives for soil and groundwater so that a
plume management strategy focusing on aggressive source treatment with flexibility
in combining technologies to best remove/ destroy contaminant mass may be
developed. A main goal of the alternatives is the original ROD target goal, which was
to treat groundwater at the source and establish a level such that the water from Well
12A would be at the 10 6 risk level with no dilution. Another goal, also referred to as a
remediation level, is to reduce the contaminant mass flux to a value, which, when
achieved, will permit the shutdown of the GETS at the Time Oil property. In
addition, land use controls, groundwater monitoring, and documented controls on
the management, use, and monitoring of the aquifer by the City of Tacoma are
incorporated into the FFS alternatives. Therefore, the components of an effective
plume management strategy are adequate use of robust source term removal
technologies; timely transition to cost-effective polishing steps; reduce/eliminate the
need for pump and treat; and, appropriate reliance on monitoring.
CDM
Well 12A FFS April 2009
1-1
-------
Section 1
Introduction
This FFS is for soil and groundwater. However, vapor intrusion is also a concern and
is being evaluated by EPA after targeted soil and groundwater contamination is
addressed.
Several historical documents and files were accessed for site specific information as
referenced in the last section of this report. Also, during the course of the FFS, two
field events were conducted to collect data on current groundwater conditions. The
data collected during those events are presented in:
¦ Well 12A Focused Feasibility Study Monitored Natural Attenuation
Evaluation Memorandum by CDM dated August 4, 2008
¦ Final Technical Memorandum Well 12A Superfund Site Groundwater Data
and Water Level Summary by Parametrix dated September 29, 2008
The primary objective of this report is to provide the regulatory agencies with
sufficient data to select a feasible and cost-effective remedial alternative. The report
documents the basis and procedures used in identifying, developing, screening, and
evaluating a range of remedial alternatives for site soil and groundwater.
1.1.2 Report Organization
This FFS report is comprised of six sections
Section 1, Introduction, describes the purpose and organization of the report.
Section 2, Site Characterization, provides a summary of site background information
including the site description, site history, description of physical characteristics of the
site, investigation activities, nature and extent of contamination, and results of a
Johnson and Ettinger Screening for vapor intrusion.
Section 3, Identification of Remedial Action Objectives, presents the assessment and
selection of treatment zones; develops a list of remedial action objectives (RAOs) by
considering the characterization of contaminants, compliance with site-specific
applicable or relevant and appropriate requirements (ARARs) and the assumed
preliminary remedial goals (PRGs); documents the estimated quantities of
contaminated media; and identifies and screens remedial technologies and process
options.
Section 4, Development and Detailed Evaluation of Remedial Alternatives, presents
the remedial alternatives developed by combining the feasible technologies and
process options. This section also describes the detailed analysis of each alternative
according to the following seven criteria: overall protection of human health and the
environment; compliance with ARARs; long-term effectiveness and permanence;
reduction of toxicity, mobility, or volume through treatment; short-term effectiveness;
implementability; and cost.
Section 5, Comparative Analysis of Alternatives, provides an overall comparison
among the various remedial alternatives in Section 4.0.
CDM
Well 12A FFS April 2009
1-2
-------
Section 1
Introduction
Section 6, References, provides a list of references used to prepare the FFS.
CDM
Well 12A FFS April 2009
1-3
-------
Section 2
Site Characterization
This section presents a description of the site history and physical characteristics of
the site. It also presents a brief summary of previous investigations, site
characterization data, the nature and extent of contamination across the site by
location and by media of concern, and the conceptual site model (CSM).
2.1 Site Description and Background
This section presents site history, previous investigations and remedial actions,
geology and hydrogeology, and the nature and extent of contamination.
2.1.1 Site Description
The site is located in Township 20 North, Range 3 East, Sections 7 and 18, at
approximately 122°28'19" W longitude and 47°13'52" N latitude (Tacoma South
Quadrangle, USGS 1981). The site includes the area surrounding the City of Tacoma
Water Supply Well 12A and the former Time Oil Company property, which is the
suspected source of contamination. The site consists primarily of
industrial/commercial land, with a small amount of residential land, in southwestern
Tacoma, Washington. The site is approximately 4 miles southwest of the
southernmost tip of Commencement Bay near the junction of Interstate 5 and State
Highway 16 (Figure 2-1). The exact area of the site is not well defined but is generally
considered to be about one square mile.
Well 12A is located in the southern and southwest portion of the site, on Pine Street
between 38th Avenue and South Tacoma Way. It is the northernmost well in the City
of Tacoma south well field. The Time Oil property is located in the northern portion
of the site, approximately one-third of a mile north-northeast of Well 12A. The Time
Oil Property, located at 3011 South Fife Street, is irregularly shaped and covers an
area of about 2.5 acres between the Burlington Northern Railroad tracks to the north
and South Tacoma Way to the south. Figure 2-2 shows an area map of well locations
at the site and Figure 2-3 shows the location of the building at the Time Oil property
and nearby wells.
2.1.2 Site History
In 1923 or 1924, a paint and lacquer thinner manufacturing facility and an oil
recycling facility began operating at the site. The paint and lacquer thinner
manufacturing process involved the use of many solvents that were stored on the site
in barrels, some of which may have leaked. The waste-oil recycling process consisted
of collecting waste oil in a large tank, adding chemicals such as sulfuric acid, and
pressurizing and heating the contents of the vessel. Absorbents and clay materials
were also added to the oil. This process resulted in the formation of a tar-like sludge
on the bottom of the tank. The sludge was filtered from the oil, and the resulting filter
cake was disposed of or stored in various piles on the site. Some of this sludge was
also used for fill around the site.
CDM
Well 12A Final FFS April 2009
2-1
-------
Section 2
Site Characterization
These operations continued until 1964 when Time Oil Company acquired the majority
of the property at 3011 South Fife Street. After purchasing the facility, Time Oil
stopped the paint and lacquer thinner manufacturing activities and concentrated on
reprocessing waste oil. This continued until 1970 when the oil re-refining operation
was terminated. From 1970 to 1972 the facility was used by Time Oil as a warehouse
for tires, batteries, and accessories. From 1972 to 1976, the portion of the property that
had previously been involved in the oil reprocessing operation was leased to Golden
Penn, Inc., who continued the operation. Oil reprocessing ceased in April 1976
following a fire at the facility that destroyed the waste-oil processing apparatus. In
1975 and 1976, Golden Penn was ordered by the State of Washington to clean up the
site by removing some of the filter cake and spilled oil from the ground. In 1976,
Golden Penn went out of business as a result of the fire.
In 1976, Time Oil resumed operation at the site with its operations limited to the
canning of oil. In 1982, the Burlington Northern Railroad spur was extended by Time
Oil to its present length so that oil could be delivered by tanker car. During the
construction of the spur, some of the filter cake or sludge material stored on the site
was used in the roadbed. Time Oil was the sole occupant of the premises and
continued to use it as a warehouse and for canning oil until the early 1990s. The area
west of the Time Oil Building was vacated in 1991, and storage tanks and associated
piping were removed at that time. Recent uses of the Time Oil property include
warehousing of heating, ventilating, and air conditioning (HVAC) equipment and
small-scale manufacturing of kayaks. In 2003 the property was sold to Western
Moving and Storage and has been primarily used for storage. Items continue to be
stored at the property today.
2.1.3 Previous Remedial Actions and Investigations
In 1981, chlorinated organic solvents were detected in Well 12A, a municipal water
supply well owned and operated by the City of Tacoma Water Department. EPA
conducted a site investigation during the summer of 1981, and concentrations of
chlorinated organic solvents detected in the well were high enough to remove the
well from service. Based on the findings of the investigation, the site was proposed for
listing on the National Priorities List (NPL) on September 1,1981. Well 12A was
added to the NPL on September 8,1983.
An air-stripping treatment system was constructed for Well 12A and began operation
in July 1983. The system was operated by the City until early November 1983 when
the well was no longer needed for the season. Well 12A and the treatment system
continued to be used to meet peak summer demand throughout the 1980s and 1990s;
however, due to the cost of operating the treatment system, the use of the well has
gradually declined over the years. Well 12A is typically now pumped only during the
summer or early fall.
The Burlington Northern Railroad Company right-of-way adjacent to the Time Oil
facility was identified by EPA as a source of contamination to Well 12A. As part of
the program to clean up the contamination, Burlington Northern agreed to excavate
contaminated soil from its railroad spur. In June 1986, Burlington Northern excavated
CDM
Well 12A Final FFS April 2009
2-2
-------
Section 2
Site Characterization
approximately 1,200 cubic yards of contaminated soils along the rail spur north of the
Time Oil property. In addition to the excavation in the railroad spur, contaminated
soil on a narrow strip of land just west of the current SVE building was excavated
(Figure 2-3). At the time, a layer of filter cake was observed in the western sidewall of
the excavation at a shallow depth, extending west for an unknown distance (Maurer
2003 as cited in URS 2005).
In November 1988, the GETS began operation to pump and treat contaminated
groundwater near the source on the Time Oil property. Groundwater is extracted
continuously from the aquifer underlying the Time Oil site and pumped through
activated carbon to remove volatile organic compounds (VOCs). The initial system
consisted of a single groundwater extraction well, EW-1. In 1995, four additional
extraction wells (EW-2 through EW-5) were added to the system. Between 1988 and
December 2002, the GETS treated over 550 million gallons of groundwater, removing
approximately 16,000 pounds of VOCs. The overall objective of the GETS is to limit
migration of the dissolved contaminants in the groundwater. All of the wells of the
GETS continue to operate.
In August 1993, an SVE system began operation in the area west of the Time Oil
Building where drum storage and disposal operations had previously occurred.
During construction of the SVE, approximately 5,000 cubic yards of a waste sludge
(filter cake) from the oil recycling operations were excavated. Operation of the SVE
was discontinued in 1997. Between 1994 and May 1997 the SVE removed
approximately 54,100 pounds of VOCs. Approximately 25 percent of the VOCs were
chlorinated and the remainder were light-end hydrocarbons. Although the SVE
equipment is still on site, it is in poor condition since it has not been used or
maintained since it was shut down in 1997.
In 2004/2005 the EPA installed wells and collected soil samples and groundwater
samples as part of a capture zone analysis. Oily product was identified in some soil
samples. Groundwater contaminant concentrations and distribution had decreased,
in general, compared to previous sampling events, with elevated concentrations of
chlorinated VOCs (CVOCs) still found near the Time Oil property. Also, several lines
of evidence suggested a capture zone, but the extent of the zone is highly uncertain in
some areas. The results of the sampling and capture zone analysis are located in Draft
Final Field Investigation and Capture Zone Analysis Report Commencement Bay/South
Tacoma Channel/Well 12A Superjund Site Tacoma, Washington (URS 2005).
2.1.4 Site Geology and Hydrogeology
The Well 12A site is located within the Puget Sound Lowland, approximately 6 miles
south of Commencement Bay and within the Commencement Bay drainage area. The
site is underlain by glacial deposits resulting from glacial and glaciofluvial processes
of the most recent glaciation. Several distinct channels, one being the South Tacoma
Channel where the site is located, were cut into these deposits by high velocity glacial
meltwater. The large glacial outwash channels are significant hydrologically in that,
where they occur below the water table, wells completed in the coarse sand and
gravel filling the channels tend to produce high yields.
CDM
Well 12A Final FFS April 2009
2-3
-------
Section 2
Site Characterization
The South Tacoma Channel, a steep-sided glacial outwash depression trends west-
southwest from Commencement Bay in the direction of the former Time Oil property
and Well 12A. Ground surface elevations along the South Tacoma Channel range
from sea level at Commencement Bay, to about 250 to 255 feet above mean sea level
(msl) at the former Time Oil property, to about 310 feet msl at Well 12A.
The local stratigraphy in the vicinity of the former Time Oil property is complex and
characterized by discontinuous local lenses of high and low permeability sediments.
As a result, the hydraulic conductivity is highly variable across the site. A semi-
confining unit exists at elevations between approximately 120 and 150 feet msl in the
vicinity of the Time Oil property and appears to be continuous beneath the property
and to a distance of at least 500 ft from the former Time Oil Building, in the direction
of Well 12A. The shallow groundwater system above the semi-confining unit is
referred to as the upper aquifer and the lower groundwater system below the semi-
confining unit is referred to as the lower aquifer.
The majority of the groundwater flow occurs in the upper aquifer (Brown and
Caldwell 1985). Beneath the former Time Oil property, the upper aquifer extends
from land surface down to approximately 100 ft below ground surface (bgs) and the
water table occurs at approximately 33 ft bgs. The underlying semi-confining unit is
approximately 30-40 ft thick and the lower aquifer is estimated to be approximately 40
ft thick. Underlying these units is the Kitsap Formation which is a regional confining
unit, but can be absent in some offsite areas (Brown and Caldwell 1985).
Regional groundwater flow is generally toward the east and southeast with a
relatively flat gradient. With the GETS operating, a capture zone is created.
Therefore gradients in the immediate vicinity of the Time Oil property and south to
near South Tacoma Way are toward the extraction wells. Several lines of evidence
suggest capture zone geometries, but the exact extent of the capture zone has not been
clearly delineated (URS 2005). Figure 2-4 shows capture zones that have been
estimated for the GETS.
Water level measurements indicate a relatively strong downward vertical gradient
both within the upper aquifer and between the upper and lower aquifers. However,
limited to no contamination in the lower aquifer suggests that the semi-confining unit
prohibits contamination from migrating to depth onsite.
Also, during operation, groundwater extraction at Well 12A depresses the
potentiometric surface and changes the normal groundwater flow direction in the
vicinity of the site. However, recent operation of Well 12A has been limited to a few
days during the summer months when demand is high. Appendix A discusses the
impact of Well 12A on the movement of contaminants.
2.1.5 Nature and Extent of Contamination
The Time Oil property had historically been used for various practices including oil
recycling as well as paint and lacquer manufacturing. Oil recycling and solvent
processing began as early as 1923and continued to 1991 with occasional interruptions
CDM
Well 12A Final FFS April 2009
2-4
-------
Section 2
Site Characterization
due to changes in ownership and a large fire in 1976. The Time Oil Company vacated
the premises in 1991, and the space has since been used for storage and small-scale
manufacturing.
In addition to a number of possible leaks and spills over the years, some of the filter
cake generated during oil recycling was used as fill material in 1982 for constructing
the Burlington North Railroad spur to the north of the Time Oil Property. Subsequent
investigations have identified this filter cake as a primary source of 1,1,2,2-
tetrachloroethane (PCA), tetrachloroethylene (PCE), and other organic solvents
discovered in the groundwater at Well 12A.
2.1.5.1 Soil
The most recent soil samples were collected during installation of wells MW-301,
MW-302, MW-304, MW-305, MW-306, MW-307, and MW-308 (URS 2005). Soil
samples were analyzed in the field by the Environmental Services Assistance Team
(ESAT) mobile laboratory for the following contaminants: TCE, PCE, 1,1,2,2-PCA,
trans-1,2-DCE, and cis-l,2-DCE.
Soil samples near the source area contained the highest concentrations. Specifically,
the most contaminated soil was found at MW-301 about 10 feet below the water table
on top of a thin clayey silt layer. Concentrations at MW-301 were generally two to
four orders of magnitude higher than contaminant concentrations detected in the soil
at the other wells. The next highest concentrations were found at MW-304, where
detections of contaminants in soil occurred almost entirely in the unsaturated zone,
except for one detection within the semi-confining unit. The highest concentrations in
MW-304 were found at the surface in a thin dark layer (less than 1 foot thick) believed
to be residual filter cake directly below the concrete pavement.
Farther from the source, at MW-306, contamination was generally located within 10
feet above and below the water table. At MW-307, soil contamination was detected
just below the ground surface, then not until just below the water table. Only TCE
was found at MW-308, the farthest well from the source, extending from the water
table down through the aquifer and into the semi-confining layer. No contaminants
were detected in lower aquifer soils in any of the newly drilled monitoring wells.
Figures 2-5 through 2-9 post soil concentrations of PCE, TCE, cis-l,2-DCE, trans-1,2-
DCE and 1,1,2,2-PCA, respectively. The soil concentrations were compared against
Model Toxics Control Act (MTCA) B modified level soil cleanup standards and soil to
groundwater pathway cleanup levels. Method A, B, and B modified level cleanup
standards are presented in Table 2-1. The A levels are reported values and, therefore,
are not calculated. Development of the B and B modified levels are shown in Tables
2-2 and 2-3. The soil to groundwater pathway Method B cleanup levels are shown in
Table 2-4.
As shown in the figures, B levels are exceeded for PCE, TCE and 1,1,2,2-PCA, with the
exceedances focused on the east side of the Time Oil building. Since TCE and 1,1,2,2-
PCA concentrations exceed their respective screening level most often, Figures 2-10
CDM
Well 12A Final FFS April 2009
2-5
-------
Section 2
Site Characterization
and 2-11 were prepared to present the extent of soil contamination for these two
compounds, respectively. As can be seen in the figures, soil contamination is greatest
near the surface on the east side of the Time Oil building. The contamination extends
downward to the water table, which suggests a continuing source to groundwater.
The figures also illustrate that limited quantities of soil contamination exist in the
vadose zone beneath the Time Oil Building and locations to the west. However, the
level of soil contamination increases again in the capillary fringe. These figures were
prepared using the data described above from the 300-series wells and also historical
data back to 1984. However, soil data that were collected in the SVE treatment area
before or during operation of the SVE were not included. Additional data collected
during remedial design and construction will be used to verify and update the CSM
as appropriate.
2.1.5.2 Groundwater
Groundwater samples have been collected during numerous events over the history
of the site, with the samples analyzed most commonly for VOCs. The primary VOC
contaminants of concern are PCE, TCE, 1,2-DCE (cis and trans), and vinyl chloride
based on risk evaluations. Also, 1,1,2,2-PCA is a primary concern since very elevated
concentrations of this compound are found in soil and in groundwater near the source
areas. Also, 1,4 dioxane is considered a concern since it has been detected in site
groundwater in previous events, can migrate readily in groundwater, and has a low
health criterion (6.1 (ig/L).
A comprehensive round of groundwater samples was collected in February/March
2008, with the analytical data from this event used to support the FFS evaluation. The
results of the analyses are summarized in Table 2-5. Regulatory criteria are posted for
the seven compounds of concern. As shown in the table, the CVOC criteria were
exceeded at several locations, with the highest concentrations occurring at EW-4, EW-
5, CH2M-1 and ICF-2. These wells are located at the south end of the Time Oil
property and south of the property. While these data from the February/March 2008
sampling event are the most recent and are generally comparable with other recent
data sets, they represent a single point in time and may not adequately account for
variability that may result from seasonal fluctuations or variations in pumping
scenarios for Well 12A or the GETS. Additional data collected during remedial design
and construction will be used to verify and update the CSM as appropriate.
Figures 2-12 through 2-14 present the isoconcentrations maps for TCE, cis-l,2-DCE
and 1,1,2,2-PCA in groundwater. These three compounds provide a reasonable
depiction of the distribution of site groundwater impacts. As shown in the figures,
TCE is the most widespread VOC, with a plume extending east and southwest
(towards Well 12A) of the site and the highest concentrations reported south of the
Time Oil property. The cis-l,2-DCE plume is much smaller than the TCE plume, with
the highest concentrations located on the Time Oil property. Elevated concentrations
of 1,1,2,2-PCA were detected in wells on and south of the property.
Figure 2-15 presents the distribution of 1,4 dioxane in groundwater. Except for one
well, MW-A, the criterion exceedances for this mobile contaminant are restricted to
CDM
Well 12A Final FFS April 2009
2-6
-------
Section 2
Site Characterization
wells at or near the Time Oil property. However, the concentration from MW-A is 7.2
(ig/L, only 1.1 (ig/L above the criterion of 6.1 (ig/L.
In addition to the standard contaminant sampling in February/March 2008, samples
were analyzed for monitored natural attenuation (MNA) parameters in June 2008.
The memorandum presenting the MNA results and interpretation is found in
Appendix B. As detailed in the memorandum, the groundwater near the Time Oil
property is conducive to anaerobic degradation; at distal locations the aquifer is
conducive to aerobic biodegradation. However, it appears that the carbon food
source near the site has been depleted and anaerobic degradation has subsided. At
distal locations, enzyme activity, oxygen concentrations and decreasing TCE
concentrations with no daughter products detected, indicate cometabolic aerobic
degradation is active. Figure 2-16 presents a summary of the intrinsic bioremediation
evaluation and identifies the anaerobic and aerobic conditions.
LNAPL and DNAPL
Despite previous remedial efforts, a number of sources of dissolved phase
contamination still remain on or near the Time Oil property. Both light and dense
non-aqueous phase liquids (LNAPL and DNAPL) have been identified beneath the
property and an additional area of filter cake has been identified to the east of the
Time Oil building. The LNAPL exists primarily within a smear zone near the water
table where it coats soil particles and partially fills voids in the soil. The presence of
DNAPL is evidenced by high soil concentrations of chlorinated solvents (in excess of
29,500 mg/kg of combined 1,1,2,2 PCA and PCE, as stated in Table 3-1 of the 1999
Groundwater Summary Report [ICF Kaiser 1999]) at depths below the historical low
groundwater level of 40 feet below ground surface.
During the February/March 2008 sampling event, 1.41 ft of LNAPL was detected at
ICF-4, which is located east of the Time Oil building. Also, trace amounts of LNAPL
were detected at TOW-6; TOW-7; EW-4; MW-1; and MW-3. All of these wells, except
EW-4, and also MW-2, MW-17, TOW-5, and MW-15 have had historical detections of
LNAPL. While the LNAPL does not appear to be widespread throughout the source
area, it has been observed at several locations and is likely a significant source of
VOCs in the source area.
2.2 Conceptual Site Model
The Conceptual Site Model (CSM) presents a description of the contaminant
distribution, examines fate and transport issues, and identifies contaminant pathways
and the influence on receptors.
2.2.1 Fate and Transport
In order to develop appropriate response actions and remedial alternatives for the
site, the fate and transport of contaminants of concern (COC) in the environment is
considered.
CDM
Well 12A Final FFS April 2009
2-7
-------
Section 2
Site Characterization
The fate and transport of contaminants is presented by providing the following:
¦ COCs
¦ Summary of potential contaminant transport pathways
¦ Risk Evaluation
2.2.1.1 Contaminants of Concern
The COCs are PCE; TCE; cis-l,2-DCE; trans-l,2-DCE; VC; and 1,1,2,2-PC A. Based on
risk evaluations, PCE, TCE, 1,2-DCE (cis-l,2-DCE and trans 1,2-DCE), and vinyl
chloride are concerns and since 1,1,2,2-PCA occurs at elevated concentrations in soil
and in groundwater near the source areas, it is also a concern. The ether 1,4-dioxane
is not considered a contaminant of concern since it is located at depth in the shallow
aquifer and it is not detected at significant concentrations beyond the contaminant
source area.
2.2.1.2 Contaminant Transport Pathways and Mass Distribution
The various environmental media onsite present several potential pathways for
contaminant migration. The fate and transport of these COCs are determined by their
physical and chemical properties in combination with the physical characteristics of
the site and source area. In the subsurface, these compounds travel rapidly with
water. 1,4-dioxane is the most mobile of the group, and is typically found at the
leading edges of plumes.
Although the chemical and physical properties of these compounds play a significant
role in the persistence and mobility, the high transmissivity of the aquifer beneath the
site is the most important feature that enhances the movement of the contaminants.
Very transmissive units of sand and gravel are present in the subsurface and the large
open voids in this material allow for easy migration of volatiles and hydrophobic
contaminants. Where the sand and gravel is interrupted or interbedded with finer
grained units, migration of the contaminant is slowed.
Estimating mass distribution is important in helping to identify and evaluate
applicable remedial technologies. Table 2-6 lists contaminant mass in groundwater
for select compounds and for total site COCs. As shown in the table, a majority of the
COC mass occurs at concentrations above 1,000 (ig/L. The table also illustrates that
the mass of 1,4 dioxane is negligible compared to that of the chlorinated compounds.
Tables 2-7 and 2-8 provide a measure of the contaminant mass and associated aquifer
volume by concentration interval in the groundwater and soil, respectively. Table 2-7
illustrates that the mass of TCE and 1,1,2,2 PCA in soil at concentrations within the
>1,000 (ig/kg is not appreciably larger than the mass within the 10,000 (ig/kg contour,
even though the volume of soil within 1,000 ug/kg is four times larger than the
volume within 10,000 ug/kg. Also, Table 2-8 demonstrates that TCE, trans-l,2,-DCE
and 1,1,2,2 PCA constitute a majority of the mass.
CDM
Well 12A Final FFS April 2009
2-8
-------
Section 2
Site Characterization
2.2.1.3 Risk Evaluation
Several potential risks have been identified:
¦ Groundwater - Ingestion, dermal contact, inhalation of vapors
¦ Vapors - inhalation of vapors migrating from the subsurface and
accumulating in buildings
¦ Shallow Soil/Filter Cake - ingestion and dermal contact
The purpose of this FFS is to address risk from groundwater and shallow soil/ filter
cake. The potential for vapor intrusion is also a concern to EPA. A recent Johnson-
Ettinger (JE) screening performed by EPA indicates a risk to residential human health
(Appendix C). The screening evaluated the machine shop building, located
immediately south of the Time Oil property, that is at the center of VOC
contamination. Following JE protocol, the concentrations at wells within 100 ft of the
building were used. The highest TCE concentration within 100 ft of the building is
CH2M-1 (1,100 (ig/L). Although the highest concentration of TCE (1,300 (ig/L) was
reported at ICF-2, this value was not used since it lies 200 ft from the machine shop.
Vapor intrusion is a concern and will be evaluated by EPA after targeted soil and
groundwater contamination is addressed.
2.2.2 Conceptual Site Model Overview
This proposed CSM builds upon the interpretation of the investigations described and
summarized in the LNAPL and Soil Investigation Report (ICF Kaiser 1999) and in the
Capture Zone Analysis Report (URS 2005).
The contamination initiated with the release of solvents and petroleum hydrocarbon
fluids to the surface soils surrounding the Time Oil building. As discussed in Section
2.1.2, solvents associated with paint thinner manufacturing and petroleum
hydrocarbon liquids associated with motor oil reprocessing were released to soils
under barrel storage, storage tank, and railroad spur loading areas. In addition, spent
filter cake, a fine-grained filtration medium used to filter oil at the Time Oil property,
was spread on the ground in areas west, north, and east of the Time Oil building. The
soil under the older, southern part of the Time Oil building has not yet been
characterized. The industrial activities associated with these releases extend as far
back as 1923. Exact dates of the releases are unknown but probably extended over a
period of decades. The quantity and precise inventory of the chemicals released to
the subsurface are also unknown.
These source areas, contaminant releases, and various groundwater withdrawals (the
Tacoma supply wells and GETS wells) have resulted in a complex distribution of
subsurface contamination. Between 1994 and May 1997, the SVE system removed
approximately 54,100 pounds of VOCs. Because of the successful operation of the
SVE from 1993 to 1997, a zone of soil extending from the surface to near the water
table (approximately 35 feet bgs) in the areas immediately west and north of the Time
Oil building has reduced concentrations of VOCs.
CDM
Well 12A Final FFS April 2009
2-9
-------
Section 2
Site Characterization
The largest VOC concentrations in the vadose zone appear to be on the east side of the
Time Oil building. These concentrations extend from near the surface down to the
water table, suggesting a continuing contaminant source to the aquifer. West of the
Time Oil building, SVE has decreased soil concentrations and it appears that the
degree and extent of contamination is limited in the vadose zone in this area of the
site. At the capillary fringe, soil contamination extends from the east side of the Time
Oil building to the southwest. Contamination in the capillary fringe away from the
source is likely due to contaminated groundwater smearing VOCs into the soil strata.
Well ICF-4, below the heavily contaminated soil on the east side of the building had
the thickest layer of LNAPL measured in 2008, which is an indication the area
continues to be a primary source area. Trace amounts of LNAPL measured in wells to
the north and southwest of the Time Oil building suggest smaller residual sources in
these areas.
Contaminated groundwater migrates toward the five GETS extraction wells as shown
in Figure 2-17. As shown in the figure, flow gradients at the Time Oil building and
areas to the south indicate groundwater is captured by the wells. However, some
uncertainty exists regarding the extent of the capture zone as illustrated by the four
capture zones in the figure. The modeled capture zone does not extend as far to the
northeast of the Time Oil building as groundwater measurements suggest. In this
area, contamination may migrate toward the east if it is not captured. However, since
negligible groundwater contaminant concentrations have been found to the northeast,
it is assumed that the capture zone extends to the northeast as indicated by the
groundwater level measurements.
More significantly, to the southeast, numerical modeling data suggest that
groundwater at CH2M-1, and possibly ICF-2, is captured by the southern extraction
wells. However, as discussed in previous reports, contaminant concentrations
continue to increase at ICF-2 (URS 2005). These increasing concentrations indicate
capture is lost in this area and the prevailing gradient may be from near CH2M-1 to
the southeast toward ICF-2. Conflicting with that prevailing gradient, the mapped
potentiometric contours suggest the prevailing gradient is to the east. Therefore, in
this area of the plume three data sets suggest three possible prevailing gradients:
northeast toward the extraction wells, southeast as indicated by increasing VOC
concentrations at ICF-2, and east following measured groundwater gradients. Since
the groundwater contaminant plume for TCE and cis-l,2-DCE extends to the east, this
direction is believed to be the prevailing gradient in this area. However, no wells are
located immediately east of ICF-2 and therefore, the uncertainty of the plume
concentrations is high. If additional data (new wells for water levels and
groundwater contamination concentrations) are collected, a different interpretation
may result.
The complexity of the capture zone geometry is compounded when the operation of
Well 12A is considered. When Well 12A is operating, the hydraulic gradient is to the
southwest with capture still occurring around the GETS wells. In recent years Well
12A has only operated a few days or weeks during summer months to fulfill demand.
CDM
Well 12A Final FFS April 2009
2-10
-------
Section 2
Site Characterization
Therefore, its recent impacts are minimal. The interpretation of Well 12A impacts are,
in summary, when the well operates for significant periods (e.g., the three summer
months), contamination associated with the Time Oil site migrates to the well.
However, using available data, estimates of plume distribution with numerical
modeling techniques do not acceptably match observed concentrations. The
numerical model does not predict contaminant transport to the well; rather, the
contamination migrates toward the east over time. The difference suggests that the
subsurface characteristics are variable and the material is heterogeneous. Preferred
pathways that allow contaminant migration toward sinks (e.g., Well 12A) may exist
that have not been identified.
In the source area anaerobic degradation has reduced groundwater TCE
concentrations. Although present anoxic conditions are still conducive to anaerobic
biodegradation, the carbon food source (aromatic hydrocarbons) has apparently been
depleted and the degradation has stalled. This incomplete degradation has caused
the greatest concentration of cis-l,2-DCE to remain within the source area and the
highest concentrations of TCE in groundwater are present south and southwest of the
GETS extraction wells (i.e., at and around the region of South Tacoma Way), where
the impact of anaerobic degradation is not as significant as it is nearer the source.
South of South Tacoma Way and also to the east of the site, site data (e.g., elevated
dissolved oxygen, decreasing TCE concentrations with few/no measurable daughter
products, and elevated enzyme activity probe data) suggest cometabolic aerobic
degradation is occurring in the low concentration plume.
CDM
Well 12A Final FFS April 2009
2-11
-------
Section 3
Identification of Remedial Action
Objectives
Applicable or Relevant and Appropriate Requirements (ARARs) are defined and
Remedial Action Objectives (RAOs) are identified. The RAOs are centered on
aggressive source treatment for management of contaminant migration.
3.1 Identification of Potential Applicable or Relevant
and Appropriate Requirements
Section 121 of CERCLA specifies that remedial actions for cleanup of hazardous
substances must comply with Federal or State environmental regulations and laws
that either specifically address, and are therefore directly applicable, to a substance or
particular circumstance at a site or, while not directly applicable, address situations
that are sufficiently similar (relevant) and are well suited (appropriate) for use at the
site. An environmental regulation or law that is not applicable must be both relevant
and appropriate to be considered an ARAR.
Inherent in the evaluation of ARARs is the assumption that protection of human
health and the environment is ensured, and the primary concern in developing RAOs
for a hazardous waste site under CERCLA is defining the degree of protection for
each proposed remedy. Section 121 of the Superfund Amendments and
Reauthorization Act of 1986 (SARA) mandates that selected remedies achieve or
legally waive ARARS. The purpose of this requirement is to make response actions
executed under CERCLA comply with pertinent Federal and State environmental
requirements.
This section provides a preliminary discussion of the regulations that are applicable
or relevant and appropriate to the remediation of the contaminated media, which is
soil (includes soil/ filter cake) and groundwater. Both Federal and Washington
environmental regulations and public health requirements are evaluated. In addition,
this section identifies Federal and Washington criteria, advisories, and guidance as
TBCs.
3.1.1 Definition and Types of ARARs
EPA defines "Applicable Requirements" as those cleanup standards and
requirements promulgated under Federal or State environmental or siting laws that
specifically address a hazardous substance or chemical, remedial action, or location at
a CERCLA site. Applicable requirements must directly and fully address the
situation at the site. For example, if the selected remedy at a site calls for the creation
of a new onsite land disposal unit that will receive RCRA hazardous waste, RCRA
minimum technology requirements and any State facility siting law would be directly
applicable to that action and therefore ARAR.
CDM
Well 12A Final FFS April 2009
3-1
-------
Section 3
Identification of Remedial Action Objectives
EPA defines "Relevant and Appropriate Requirements" as those cleanup standards
and requirements promulgated under Federal or State environmental or siting laws
that, while not directly applicable, are both sufficiently similar and well suited to
address a hazardous substance or chemical, remedial action, or location at a CERCLA
site. For example, Maximum Contaminant Levels (MCLs) under the Safe Drinking
Water Act are often used as cleanup levels for contaminated groundwater. Since
MCLs regulate public water suppliers, they are not applicable to groundwater
cleanup, however since the MCL is protective of drinking water, the standard is
sufficiently similar and well suited as a protectiveness standard in most cases.
State ARARs take precedence over Federal counterparts when they are: 1) a state
environmental law of facility siting law; 2) promulgated; 3) more stringent; 4)
identified by the State in a timely manner; and 5) consistently applied.
ARARs are not currently available for every chemical, location, medium or action that
may be encountered. When ARARs are not available, PRGs may be based upon other
Federal or State criteria, guidance, or local ordinances. This information is known as
"To Be Considered" or TBC. TBCs may be used to determine the necessary level of
protection for certain remedial alternatives, and are generally used when ARARs do
not exist or are not protective.
ARARs and TBCs are both used during the FS process to evaluate the remedial
alternatives. ARARs and TBCs are evaluated and, as appropriate, may be used to
derive PRGs that can be utilized throughout the FS process. These cleanup goals are
developed such that they meet the intent of the ARAR or TBC to be protective of
human health and the environment.
ARARs and TBCs fall into three broad categories, based on the manner in which they
are applied at a site. These categories are as follows:
Chemical-specific: These ARARs and TBCs usually are numerical values that are
health- or risk-based values or methodologies. They establish acceptable amounts or
concentration of chemicals that may be found in, or discharged to, the ambient
environment. The also may define acceptable exposure levels for a specific
contaminant in an environmental medium. They may be actual concentration-based
cleanup levels, or they may provide the basis for calculating such levels. Examples of
chemical-specific ARARs are the A, B and B-modified level criteria for soil under
Washington State Department of Ecology's MTCA.
Location-specific: These ARARs and TBCs set restrictions on remedial activities at a
site due to its proximity or location in specific natural or man-made features.
Examples of natural site features include floodplains or wetlands. Examples of man-
made features are local historic buildings and structures.
Action-specific: These ARARs and TBCs set controls or restrictions for particular
remedial activities related to the management of hazardous substances, but do not in
themselves determine what the remedial alternative should be. Selection of a
CDM
Well 12A Final FFS April 2009
3-2
-------
Section 3
Identification of Remedial Action Objectives
particular remedial action at a site will invoke the appropriate action-specific ARARs
which specify performance standards or technologies, as well as specific
environmental levels for discharged or residual chemicals. Examples of action-
specific ARARs are hazardous waste listing and disposal requirements.
ARARs apply to those Federal and State regulations that are designed to protect
public health and the environment and do not apply to occupational safety
regulations. EPA requires compliance with the OSHA standards in 40 CFR 300.150 of
the National Contingency Plan (NCP), but not through the ARARs process.
Therefore, the regulations promulgated by OSHA are not addressed as ARARs.
Chemical, location, and action-specific ARARs for the site are presented in Tables 3-1,
3-2, and 3-3, respectively.
3.2 Identification of Potential Treatment Zones and
Remediation Boundaries
The CSM (which includes the nature and extent of contamination, the location of
contaminant mass, the transport of contaminants and zones of biodegradation), in
conjunction with ARARs, is used to identify treatment zones and remediation
boundaries.
3.2.1 Filter Cake and Shallow Impacted Soil
Figure 3-1 shows the proposed treatment zone for filter cake and shallow impacted
soil. The COC 1,1, 2, 2-PCA is shown in the figure since it is the most widespread
contaminant in the soil medium. This zone has been proposed since it is at the surface
and it appears to be contributing to contamination at depth at the north side. The
continued migration of contamination at depth is indicted by the elevated
concentrations that are in the vadose zone above the capillary fringe.
The area of the treatment zone is generally rectangular in shape and measures
approximately 80 ft wide by 130 ft long. The area of the treatment zone is not a perfect
rectangle; as EVS algorithms estimate the area to be approximately 11,340 square feet
(SF). The depth of the filter cake and shallow impacted soils treatment zone is
estimated to be approximately 10 ft, since at about 10 ft bgs in the south half of the
zone the elevated concentrations of 1,1,2,2-PCA appear to terminate. In the north end,
elevated concentrations extend down into the soil column as previously noted.
Results from samples collected during future events (e.g., a design investigation) can
be used to refine the zone area and depths. Therefore, the volume estimated to be
excavated is 11,340 SF x 10 ft = 113,400 cubic feet or 4,200 cubic yards.
EVS modeling based on recent and historical soil data (see Figure 3-1) was used to
estimate the excavation volume. The approximate aerial extent was calculated taking
into account limitations associated with current site development and land use (e.g.,
buildings and railroad tracks) and the average depth of the excavation was estimated
to be 10 feet based on available soil data and feasibility considerations (e.g,, proximity
to buildings). More or less excavation may be required based on observations and
CDM
Well 12A Final FFS April 2009
3-3
-------
Section 3
Identification of Remedial Action Objectives
field screening data to be collected during the remedial action. Soil cleanup targets
for excavation will be developed and defined during remedial design. The 10-ft
excavation depth also assumes that ERH will be implemented for impacted soils
greater than 10 feet bgs. A cost-benefit analysis will be performed during the
remedial design to evaluate the most cost-effective depth to transition from
excavation to ERH.
3.2.2 Deep Vadose Zone Soil and Upper Saturated Zone East of
Time Oil Building
Figure 3-1 also shows the proposed treatment zone east of the Time Oil building for
the highly contaminated soil in the vadose zone at depth and in the groundwater.
The part of the zone below the water table is defined by the high concentrations of
CVOCs identified on soil samples found in the saturated zone. In effect, remediation
that is performed below the water table will be focused on reducing contaminant
concentrations in groundwater. However, since technologies applied in the deep
vadose zone would likely be applicable to the upper saturated zone, the two media
are combined in this one treatment zone. The extension of vadose zone
contamination into the water table suggests that it is a continuing source of
contamination. If left untreated, these high concentrations of contamination would
continue to impact groundwater.
The area of the treatment zone is generally rectangular in shape and measures
approximately 90 ft wide by 140 ft long. The treatment zone extends from a depth of
10 ft bgs to 55 ft bgs. The water table occurs at approximately 34 ft bgs in the zone.
Therefore, the upper 21 ft of the saturated zone is included. Results from samples
collected during future events (e.g., a design investigation) can be used to refine the
zone area and depths.
3.2.3 High Concentration Groundwater
Figure 3-2 presents the proposed treatment zone for the high concentration
groundwater. This area is defined by TCE and cis-1, 2, DCE in groundwater at
concentrations above 300 (ig/L. The 300 (ig/L concentration was chosen since beyond
this concentration negligible additional contaminant mass is gained. Also, at this
contour line, the aquifer begins to transition from anaerobic conditions to aerobic
conditions. Two other relatively small areas are included in the proposed treatment
zone that are outside of the 300 (ig/L isoconcentration contour. The area east of the
Time Oil building with elevated concentrations of 1,1,2,2-PCA was included (and is
discussed in the section above). Also, the area southwest of the Time Oil building that
lies underneath a large drive area for loading docks was included. The area was
included because it currently is within the capture zone of the site extraction wells
and limited data are available in the area (i.e., possible contamination is present but
not detected).
CDM
Well 12A Final FFS April 2009
3-4
-------
Section 3
Identification of Remedial Action Objectives
3.2.4 Low Concentration Groundwater
Figure 3-2 also presents the proposed treatment area for the dissolved phase plume.
The treatment zone is the area beyond the 300 (ig/L isoconcentration for TCE/cis-1, 2-
DCE and extends to the distal monitoring points to the southwest (e.g., Well 12A) to
the southeast (CH2M-2) and to the east (CH2M-3). While it was observed to be
continuous beneath the Time Oil property, the semi-confining unit separating the
upper and lower aquifers does not appear to extend all the way southwest to Well
12A. As a result, southwest of the site (e.g., at MW-308), the low concentration
groundwater treatment zone includes both the upper aquifer and the upper portion of
the lower aquifer. Groundwater data from wells located in this treatment zone
generally indicate that conditions conducive to aerobic cometabolism dominate and
the degradation of CVOCs is likely occurring.
3.3 Remedial Action Objectives
Remedial Action Objectives (RAOs) have been developed in conjunction with four
defined treatment zones. A compilation of the treatment zones plus a description of
the RAOs is presented in Figure 3-3. These RAOs will result in an effective plume
management strategy to reduce contaminant mass, decrease the size of the
contaminated area and prevent contamination from impacting human health and the
environment.
Aggressive source treatment was evaluated for three defined treatment zones, which
include Filter Cake/Shallow Soil, Deep Vadose Zone Soil and Upper Saturated Zone
East of Time Oil Building, and High Concentration Groundwater. Aggressive
treatment in these zones is the primary first tier goal of the RAOs. A containment
remedy is not the main focus of the RAOs.
Filter Cake/Shallow Soil
¦ Eliminate the risk of direct contact with filter cake at and near the surface.
Eliminating the direct contact risk will also reduce possible vapor intrusion
issues. EPA will address vapor intrusion under a separate activity when
targeted soil and groundwater contamination is addressed.
¦ Prevent or minimize the migration of contamination from highly
contaminated shallow source areas into the deeper vadose zone to prevent
further degradation of deep soil and groundwater.
Deep Vadose Zone Soil and Upper Saturated Zone East of Time Oil Building
¦ Eliminate/minimize the mass of contaminants to reduce the mass flux
from this highly contaminated area to downgradient groundwater.
High Concentration Groundwater
¦ Reduce contaminant mass flux by ninety percent from the source area
through a specific plane into the low concentration groundwater treatment
zone. The proposed plane is defined by the current location of the 300
(ig/L TCE/cis-DCE isoconcentration. This flux reduction goal is a
CDM
Well 12A Final FFS April 2009
3-5
-------
Section 3
Identification of Remedial Action Objectives
groundwater remediation level to be met in order to document that active
source treatment is complete.
Low Concentration Groundwater
¦ The interim groundwater ROD Amendment remediation level (i.e., to
assure a protective remedy along with well head treatment at 12A as
needed) is to meet MCLs at compliance wells 12 A, new well CVV l, and
new well CW2.
¦ The conditional point of compliance wells are identified as CH2M2, new
well I Ml, and new well IM2. The action will be considered an interim
action until the cleanup level is attained at these wells.
Figure 3-4 shows the locations of the proposed compliance wells and conditional
points of compliance wells.
3.3.1 Mass Flux Measurement
One of the performance goals of the active source treatment is reducing contaminant
mass flux by ninety percent from the source area to the low concentration
groundwater treatment zone at the 300 (ig/L TCE/cis-DCE isoconcentration. Based
on preliminary modeling, this is likely sufficient to achieve MCLs at the proposed
compliance wells (Appendix D). Measuring this parameter is critical since it provides
a metric for the amount of contamination that is migrating away from an active
treatment zone and into a passive treatment zone. However, it will not be the only
performance standard for the strategy. For example, mass reduction in the active
treatment zone and decreases in dissolved phase concentrations in the passive
treatment zone are also expected to be performance criteria.
Mass flux will be measured using the passive flux meter technology, developed by the
University of Florida, which evaluates both contaminant mass flux and groundwater
Darcy velocity. The passive flux meter is a sock that is filled with absorbent material
and a tracer. The sock is deployed down the well within the screened interval and
allowed to be passively exposed to groundwater for some defined time interval.
Groundwater velocity is calculated based on the rate in which the tracer desorbs from
the sorbent. In addition, the rate at which contaminants (organics) sorbs to the
sorbent is used to estimate mass flux. This method was chosen because both
groundwater velocity (which is generally the term that has the greatest uncertainty in
a mass flux calculation using standard groundwater analyses) and mass flux are
directly measured.
Multiple samples will be collected at discrete vertical points along the flux meter to
measure groundwater velocity and contaminant mass flux. These data will be used to
generate vertically discrete mass flux estimates (units of mass/area/ time) that can
then be used to estimate total flux at the flux well point. In addition, multiple wells
transecting the groundwater plume can be integrated to assess total contaminant mass
flux (mass/ area/time) and contaminant discharge (units of mass/time) through a
flux well plane.
CDM
Well 12A Final FFS April 2009
3-6
-------
Section 3
Identification of Remedial Action Objectives
Overall, the data will be interpreted in two ways; changes in mass flux at discrete
points will be evaluated to determine impacts of upgradient treatment on mass flux at
those locations. For instance, flux wells that are closer to the active treatment areas
may observe changes in mass flux before locations that are further away from the
active treatment areas. This may also be used during active treatment optimization to
focus treatment to areas that are contributing relatively high contaminant mass flux.
In addition, a total mass discharge will be evaluated for the flux well planes. It is the
total mass discharge value that will be used to determine if the 90% reduction goal
has been achieved. The discharge values may be evaluated both in terms of mass flux
discharge along one of the flux well planes and total mass discharge across the flux-
plane boundary.
It is also important to note that groundwater samples will be collected in wells that
correspond to the mass flux analysis and analyzed for COCs using acceptable
analytical procedures at a much greater frequency that the mass flux analysis. These
data will be used to compare standard analytical contaminant concentration changes
as another line of evidence for mass flux changes that are observed with the passive
flux meters. In addition, groundwater analytical results will be used to determine
when to conduct a mass flux assessment. For instance, if a 90% reduction in
contaminant concentrations is observed at a flux-well pair of interest, mass flux
evaluation may be conducted to verify a corresponding reduction in mass flux.
Currently, the remedial action includes operation of the GETS system within the
source area to hydraulically capture contaminant mass before it migrates to
downgradient locations. There is substantial evidence, however, that the GETS
system does not provide sufficient hydraulic containment to prevent all contaminant
mass from migrating downgradient, as indicated by a persistent groundwater
contaminant plume outside the estimated capture zone of the GETS (Figure 3-4).
Therefore, the baseline mass flux measurement will be conducted with the GETS
system operating, but before any additional source area remedial actions are
conducted.
Figure 3-4 shows the proposed flux measurement plane and the wells that will be
used to measure flux relative to the estimated capture zone(s) of the GETS and the
TCE contaminant plume isopleths. A flux estimate at the proposed plane will provide
a measure on the impacts of remedial actions in the source areas and high TCE
concentration groundwater. The location of the plane has been chosen since the plane
lies
¦ at or near the downgradient edge of the high concentration groundwater
treatment zone,
¦ in the shallow aquifer where groundwater contamination is located,
¦ along four existing wells (WCC-3, CBW-10, WCC-6 and WCC-2); thus,
taking advantage of these existing measuring locations and the historical
data available from these locations.
CDM
Well 12A Final FFS April 2009
3-7
-------
Section 3
Identification of Remedial Action Objectives
The high concentration groundwater treatment zone is defined as the location where
the concentration of TCE or cis-1,2 DCE is at or above 300 (ig/L, which is shown on
Figure 3-4. Figure 3-5 compares the location of the flux plane to the TCE and cis-1,2-
DCE concentrations and bioremediation parameters. Downgradient of the proposed
flux plane (i.e., downgradient of the high concentration groundwater treatment zone)
the figure illustrates that aerobic conditions dominate.
Based on current modeling using compliance point well 12A and conditional point
compliance well CH2M-2, the ninety percent flux reduction goal is sufficient to allow
for intrinsic bioremediation to eventually achieve the MCL goals at these wells
(Appendix D). The ninety percent reduction is based on estimated mass flux across
the flux plane boundary. The analysis uses the most current known data and
standard practices to make the estimates. Additional data, such as from the passive
flux meters, may be input into the current model to revise or enhance the mass flux
estimates, or may be analyzed using other related methods (i.e., numerical modeling).
For instance, one of the greatest uncertainties in the mass flux calculation is the actual
groundwater Darcy velocity and direction at the various points along the flux plane
boundary. Therefore, passive flux meters will be used to directly measure both Darcy
velocity and mass flux at the flux plane locations. Verification of the current mass
flux discharge and validation of the ninety percent flux reduction goal will be
conducted following the baseline flux measurement using the actual groundwater
Darcy velocities measured and impacts recalculated per procedures described in
Appendix D. A discussion of methods, assumptions and uncertainties in the current
hydrological analysis used to determine the ninety percent flux reduction RAO are
discussed below.
Groundwater velocities used to estimate current and reduced mass flux is based on
Darcy velocities of 0.14 ft/ day to the east of the Time Oil source area and 1.48 ft/day
to the south of the source area. These are estimates based on the GETS system not
operating and Well 12A operating 3 months/year. As discussed in Appendix A and
D, there is significant uncertainty in the modeling inputs (i.e. hydraulic conductivity,
dispersivity, and gradient) for various portions of the contaminated subsurface
aquifer. In addition, there is likely substantive heterogeneity in the physical and
hydraulic properties of various vertical and lateral portions of the aquifer. A
combination of these uncertainties is likely the reason that there was substantial
difficulty fitting the modeling outputs to the actual dimensions of the contaminant
plume and matching predicted and actual contaminant arrival times at particular
locations.
The groundwater velocities reported in Appendix D were used to estimate when
impacts from remedial actions may be seen at the flux monitoring wells and at the
points of compliance. The distance from the south edge of South Tacoma Way (a
proposed location to receive enhanced bioremediation amendment) to proposed flux
measurement wells MW-311 and 312 is 220 feet. With a contaminant velocity of 0.42
ft/ day, reduced concentrations are estimated to be measured after approximately 524
days (220 ft/0.42 ft/day) or about eighteen months. A similar estimate can be
prepared for the distal conditional point of compliance wells. The distance from the
CDM
Well 12A Final FFS April 2009
3-8
-------
Section 3
Identification of Remedial Action Objectives
south edge of South Tacoma Way to Well 12A is approximately 1,400 ft. Therefore,
impacts on Well 12A from active remediation are estimated to be measured after
approximately 3,333 days (1,400 ft/0.42 ft/ d) or about nine years. These values are
general estimates on when impacts may be seen using current data and standard
analytical methods. However, due to the complexity of the subsurface (e.g., highly
heterogeneous) and groundwater gradients (e.g., Well 12A pumping on and off) the
actual travel times and times when the impacts of remediation is measureable may
differ.
As noted, groundwater velocities are variable and the uncertainty of groundwater
velocity is substantial. If groundwater velocities measured in the field differ from
what is estimated in this FFS, then adjustments to the remedy and performance
monitoring may need to be made. Therefore, the in-field measurement of Darcy
velocity during GETS pumping and after GETS pumping has stopped is an integral
component of the remedy. For example, flux measurements will be collected (based
on the measured Darcy velocity and not the estimated FFS velocity) when the front of
the treated groundwater is estimated to reach the flux plane.
Also, variable groundwater velocities may impact the costs of the remedy. For
example, if groundwater velocities greater than estimated are experienced at the in-
situ thermal treatment zone, then additional engineering, equipment and operations
may need to be employed so that the water is sufficiently heated for the treatment to
be successful, which would increase the costs. Conversely, if velocities are lower than
estimated, then costs to treat the zone would likely be less.
In addition to the hydrogeological analysis, the flux reduction goal is also based on an
estimation of biodegradation rates in the low concentration plume zone (Appendix
D). As there is inherent uncertainty in both of these values, the goal to reduce flux by
ninety percent is conservative. The analysis estimates that concentrations need to be
reduced by approximately 80 percent (reduce 300 (ig/L TCE down to 70 (ig/L) on the
east side of the plume using a TCE half-life of 8.25 years and approximately 50
percent (reduce 300 (ig/L TCE down to 160 (ig/L) on the southwest side of the plume
using a TCE half life of 1.5 years to achieve MCLs at downgradient wells CH2M-2 and
CBW-11. During the February/March 2008 sampling event, the TCE concentrations
at wells CH2M-2 and CBW-11 were 21 (ig/L and 8.5 (ig/L, respectively. These two
wells were included in the analysis since the February/March 2008 TCE
concentrations are above the MCL. Compliance Well 12A was not included since the
detected concentration was below the MCL. This assumes that all other parameters
(e.g., groundwater velocity) are constant and result in reductions in mass flux that are
proportional to decreases in contaminant concentration(s). The expected
concentration reductions are attributed to the natural attenuation capacity of the
aquifer in the location of the low concentration plume.
The biodegradation rates identified in the hydrogeological analysis provide, to a
certain degree, a measure of the natural attenuation capacity of the aquifer in the area
of the low concentration plume. Based on the analysis, the biodegradation rate (in
half-lives) varies from approximately 1.5 years (southwest part of the plume) to 8
CDM
Well 12A Final FFS April 2009
3-9
-------
Section 3
Identification of Remedial Action Objectives
years (east part of the plume). These rates are within the range of typical degradation
rates under aerobic conditions (Starr et al., 2005). Additionally, site data (e.g.,
elevated dissolved oxygen, decreasing TCE concentrations with few/no measurable
daughter products, and elevated enzyme activity probe data) suggest cometabolic
aerobic degradation is occurring in the low concentration plume.
Aerobic biodegradation of TCE relies on various microbial oxygenases that are
capable of cometabolic TCE degradation. Cometabolism occurs when an aerobic
microorganisms uses growth substrates (what the microorganism grows and feeds
on) and generate enzymes that react with contaminants with structural similarity to
their growth substrates. The cometabolic degradation of contaminants (i.e. TCE) does
not benefit the microorganisms directly, but is a fortuitous reaction as a result of the
presence of the enzymes. Examples of non-specific enzymes that cometabolize TCE
are methane monooxygenase, toluene monooxygenase, and propane monooxygenase.
Since the bacterium producing the enzyme derives no carbon or energy from the
process, and because the cometabolic substrate actually competes for the enzyme
active site with the growth substrate, intrinsic biodegradation occurring in aquifer
systems is relatively slow compared to other mechanisms (such as anaerobic
reductive dechlorination during EAB). Field evaluation at Well 12A has
demonstrated that aerobic enzymes capable of cometabolism of TCE are present
within the aerobic groundwater plume at Well 12A.
In light of the age of the plume, it is assumed that the current range of degradation
rates reflects an equilibrium condition that accounts for the dissolved oxygen flux, the
TCE flux, and the flux of compound(s) inducing the oxygenase enzyme(s) responsible
for cometabolic degradation. Compounds that might be inducing the enzyme(s)
include recalcitrant organics such as lignins; methane from a deep, subsurface source;
or possibly even TCE itself. Research on measuring some of these substrates and
relating concentrations to degradation rates and natural attenuation capacity is
ongoing. In any case, the site data and analysis provide convincing support that
aerobic cometabolic degradation is sufficient in the context of the established flux
goals and RAOs proposed for the site.
Degradation and interim degradation by-products vary for environments that are
anaerobic and aerobic. In general, by-products for TCE degradation under anaerobic
conditions are cis-DCE, vinyl chloride and ethene. Under aerobic conditions, carbon
dioxide, water and chloride are the end-products. The transition zone between an
anaerobic (i.e. EAB treatment zone) and aerobic plume can also facilitate alternate
degradation pathways for contaminants and degradation by-products. For instance,
vinyl chloride can be directly oxidized to carbon dioxide and water if it is transported
to an aerobic environment. The actual degradation pathways will likely be complex
and the by-products detected during performance monitoring may vary.
In addition to the contaminant concentration estimates, the hydrogeological analysis
also recognizes a difference between biodegradation rates applied on the east side of
the plume and the rates on the southwest side. Different or variable characteristics
other than biodegradation rates have also been recognized previously. For example,
CDM
Well 12A Final FFS April 2009
3-10
-------
Section 3
Identification of Remedial Action Objectives
using currently available data, estimates of plume distribution using numerical
modeling techniques do not acceptably match observed concentrations. These
observations suggest that the subsurface characteristics are variable and the material
is heterogeneous. Preferred pathways that allow contaminant migration toward sinks
(e.g., Well 12A) may exist that have not been identified. As a result, it is proposed to
continue to evaluate contaminant attenuation within the low-concentration dissolved
phase plume before, during and after any remediation conducted at the Welll2A site.
This evaluation will help to verify estimated degradation rates and determine impacts
of remedial actions on contaminant concentrations and attenuation rates in this area
of the contaminant plume.
3.4 Identification and Screening of Remedial
Technologies and Process Options
A list of remedial technologies and process options applicable to the filter cake, soil
and groundwater were developed through a review of EPA guidance documents
related to remediation of similarly contaminated material, review of regional Record
of Decision (ROD) summaries, vendor sources, and professional experience. Also, the
following EPA guidance documents were used to identify remedial technologies
applicable to the Well 12A site:
¦ Presumptive Response Strategy and Ex-Situ Treatment Technologies for
Contaminated Ground Water at CERCLA Sites (EPA 1996)
¦ Guidance for Conducting Remedial Investigations and Feasibility Studies Under
CERCLA" (USEPA, 1988)
Based on the review of remedial technologies applicable to the site, results were
developed to provide a listing of remedial technologies and process options for soil
and groundwater. The results of the technology screening evaluations are
documented in the Draft Remedial Alternatives Screening Memorandum (CDM 2008)
and summarized in the two tables presented in Appendix E with some modifications.
These tables document the preliminary screening step based on effectiveness,
implementability, and cost. Technologies and process options that were retained for
one or more treatment zones are marked with a "Y" in the "Retained? (Y/N)"
column. Technologies retained through the screening process were used to develop
the remedial alternatives for each treatment zone (see Section 4).
CDM
Well 12A Final FFS April 2009
3-11
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
In this section, remedial alternatives for the Well 12A site are assembled by combining
the remedial technologies and process options which were retained following the
screening step performed in Section 3.4. Under typical FS procedures, the list of
alternatives is then screened using the effectiveness, implementability, and cost
criteria. However, because only nine alternatives (with two being existing actions) are
developed in this section, the alternative screening step has been omitted from the
evaluation process. Rather, all nine of the alternatives are thoroughly evaluated in
this section against seven of EPA's nine evaluation criteria: overall protection of
human health and the environment; compliance with ARARs; long-term effectiveness
and permanence; reduction of toxicity, mobility, or volume through treatment; short-
term effectiveness; implementability; and cost. The remaining two EPA evaluation
criteria, support agency and community acceptance, will be addressed in future
actions by the EPA (e.g., ROD Amendment).
4.1 Remedial Alternative Development
Filter cake/soil was excavated from the site in 1986, a soil vapor extraction system
operated west of the Time Oil building from 1993 to 1997, and the GETS has operated
since 1988 (with an expansion in 1995). Also, Well 12A continues to operate with an
air stripping unit, which was installed in 1983. In spite of these site removal/remedial
activities soil and groundwater contamination still persists and EPA has elected to
aggressively treat or destroy source area contamination.
The largest concentrations of soil contamination have been identified east of the Time
Oil Building in the former East Tank Farm. Filter cake is also believed to be near the
surface in this area. Based on data visualizations, this area is believed to be a
continuing source of groundwater contamination. Elevated concentrations of
contaminants in groundwater extend from at/near the Time Oil Building to the south
and southwest. A portion of the groundwater contaminant plume is within the
capture zone of the GETS wells. However, some data suggest that elevated
concentrations of groundwater contaminants may have escaped or are continuing to
escape the capture zone in the south and southwest part of the plume. Moderate to
high uncertainty is associated with the capture zone and plume extent in this area
(i.e., at and south of South Tacoma Way). Additionally, the operation of Well 12A
impacts the geometry of the capture zone; contaminants in the southern end of the
plume are likely accelerated toward Well 12A when it is in operation. Also,
unidentified pathways (e.g., high hydraulic conductivity zones) may exist that lend to
a complex and chaotic distribution of contamination.
CDM
Well 12A Final FFS April 2009
4-1
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
A natural attenuation evaluation indicates that conditions are conducive to anaerobic
degradation in the high concentration plume (i.e., TCE and cis-1,2-DCE
concentrations > 300 (ig/L) and cometabolic aerobic degradation conditions persist in
the low concentration plume (i.e., TCE and cis-1,2-DCE concentrations < 300 (ig/L).
Given the complexity of the site, no single remedial alternative would be appropriate
as a site-wide remedy. Thus, for the purpose of developing and evaluating
appropriate remedial alternatives, the site was divided up into four treatment zones:
¦ Filter Cake and Shallow Impacted Soils (FC)
¦ Deep Vadose Zone Soil and Upper Saturated Zone East of Time Oil Building (SG)
¦ High Concentration Groundwater Plume (HG)
¦ Low Concentration Groundwater Plume (LG)
The following subsections provide a description of each treatment zone and the
alternatives for that zone that will be evaluated.
4.2 Detailed Description of Alternatives
This section provides detailed descriptions of the proposed alternatives that have
been discussed with EPA. Descriptions of these alternatives provide sufficient
information to carry out a detailed analysis. Preliminary design assumptions have
been made so that cost estimates could be prepared for each alternative. The final
configuration of the remedial alternative selected by EPA for implementation will be
determined during the remedial design phase, and will include detailed plans,
specifications, and treatment processes. Each alternative description includes a
summary of the alternative with descriptions of individual components of the
alternative. These descriptions address the site conditions that are expected to exist
during remedial activities.
4.2.1 Filter Cake and Shallow Impacted Soil
Figure 4-1 identifies the location of this treatment zone.
4.2.1.1 Alternative FC1 - No Action
Under this alternative, no action would be taken to remedy the filter cake and shallow
contaminated soils. The no action alternative is considered in accordance with NCP
requirements and provides a baseline for comparison with the other alternatives. No
further action would be conducted and the status of the filter cake and shallow
impacted soil would remain unchanged. This alternative does not include the
implementation of any institutional controls such as deed restrictions or future
groundwater monitoring. CERCLA (Section 121(c)), as amended by SARA (1986),
would require that the site be reviewed at least every 5 years since contamination
would remain on site.
CDM
Well 12A Final FFS April 2009
4-2
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
4.2.1.2 Alternative FC2—Institutional Controls
For this alternative, institutional controls (ICs) would be employed at the site to
protect human health. The ICs would be used to limit access to and future
development improvement, and use of affected properties. Specifically, ICs would
include activity and use restrictions enacted through proprietary (e.g. easements,
covenants) and/or governmental (e.g. zoning requirements) controls to prevent use of
the property that would pose an unacceptable risk to receptors (i.e. for residential
use). Informational device ICs (warning signs, advisories, additional public
education) also would be employed to limit access to contaminated soils.
In accordance with CERCLA, this alternative would be evaluated at least every five
years because contaminants would remain on site with this alternative.
4.2.1.3 Alternative FC3 — Capping Contaminated Soils In Place
This alternative consists of capping filter cake and contaminated soils in place. The
cap would be a bituminous asphalt cap which would prevent infiltration of
precipitation into underlying groundwater. Institutional controls would be
implemented to restrict future development/use and a long-term O&M program.
Long-term groundwater monitoring would also be implemented to monitor changes
in site conditions. A bituminous asphalt cap would not be necessary where a building
structure or concrete (such as sidewalks or curbing) currently exist on site.
In accordance with CERCLA, this alternative would be evaluated at least every five
years because contaminants would remain on site with this alternative.
4.2.1.4 Alternative FC4—Excavation of Soils, Transportation to and Disposal
in RCRA Subtitle C or D Landfill
This alternative consists of excavating filter cake and contaminated soils and
transporting them off site to a RCRA-permitted Subtitle C or D landfill based on
results of TCLP testing. For the purpose of this FFS, an average excavation depth of
10 feet has been assumed; however, more or less excavation may be required based on
observations and field screening data to be collected during the remedial action. Soils
near building foundations may need to remain in place to ensure structural integrity
of the building. Assuming an average excavation depth of 10 feet, approximately
4,200 cy of contaminated soils would require excavation and disposal.
After removal of contaminated soils, the excavations would be backfilled with clean
soil and gravel cover would be placed across the Site surface. For areas where
contaminated soils remain, either further in situ treatment would be performed or
institutional controls such as deed restrictions and information devices would be used
to further reduce the potential for exposure.
Water would be used to minimize fugitive dust emissions during soil excavation,
transport, and handling. Any stockpiles of material during interim storage would be
covered by tarps or plastic sheeting to minimize fugitive dust emissions and runoff
CDM
Well 12A Final FFS April 2009
4-3
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
releases. Surface water runoff, fugitive emissions and treated soils would be
monitored to ensure that the RAOs were being met.
In accordance with CERCLA, this alternative would be evaluated at least every five
years if contaminants remain onsite that are not addressed with an in situ remedy
(e.g., in situ thermal remediation).
4.2.2 Deep Vadose Zone Soil and Upper Saturated Zone East of
Time Oil Building
Figure 4-1 identifies the location of this treatment zone.
4.2.2.1 Alternative SGI - No Action
The no action alternative is considered in accordance with NCP requirements and
provides a baseline for comparison with the other alternatives. No further action
would be conducted and the status of the deep vadose soil and shallow groundwater
would remain unchanged. This alternative does not include the implementation of
any institutional controls such as deed restrictions or future groundwater monitoring.
CERCLA (Section 121(c)), as amended by SARA (1986), would require that the site be
reviewed every 5 years, because contamination would remain on site.
4.2.2.2 Alternative SG2 - Institutional Controls
For this alternative, ICs would be employed to protect human health. The ICs would
be used to limit access to and future development, improvement, and use of affected
properties. Specifically, ICs would include activity and use restrictions enacted
through proprietary (e.g. easements, covenants) and/or governmental (e.g. zoning
requirements) controls to prevent use of the property that would pose an
unacceptable risk to receptors (i.e. for residential use). Tacoma-Pierce County Board
of Health Resolution No. 2002-3411, Land Use Regulations and applicable sections of
Washington Administrative Code Titles 173 and 246 are current guidelines that
would be considered, or possibly amended, for the location and installation of supply
wells. Additional details regarding potential institutional controls associated with
Tacoma Water's use of groundwater from the South Tacoma well field are presented
in Section 4.2.4.2. Informational device ICs (warning signs, advisories, additional
public education) also would be employed to limit access to contaminated soils and
groundwater. An additional component of this alternative involves the continued
monitoring of groundwater at the site. For the purpose of cost estimating, ten wells at
and near the treatment zone would be monitored for VOCs for a period of 30 years.
In accordance with CERCLA, this alternative would be evaluated at least every five
years because contaminants would remain on site with this alternative.
4.2.2.3 Alternative SG3 - In-situ Thermal Remediation
Electrical resistance heating (ERH) is believed to be the most applicable in situ
thermal remediation (ITR) technology for the site. Prior to installing the ERH
electrodes and vapor recovery wells for the ERH system, approximately 10 soil
borings will be advanced in the treatment area to refine the selected locations of the
CDM
Well 12A Final FFS April 2009
4-4
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
treatment zone and grid. The treatment zone boundaries may be adjusted based on
results of the initial soil sampling. After the soil and shallow groundwater
concentrations are delineated, a grid of electrodes and vapor recovery wells will be
installed. For the purpose of this estimate, a grid of 52 electrodes separated, on
average, by 20 ft and installed to a depth of 57 ft is assumed. A grid of 52 co-located
vapor recovery wells will also be installed. For this estimate, approximately half of
the piping and conduit will be installed below ground surface in this relatively open
lot. However, if the shallow impacted soil is excavated, then the piping may be
placed below grade prior to returning the excavated area to grade. The vapor will be
treated using granular activated carbon (GAC). During operation, temperature,
groundwater quality, vapor emissions and condensate/discharge will be monitored.
During heating, the following monitoring is proposed
¦ Temperature - temperature monitoring sensors (TMS) may be proposed for
vapor extraction wells, groundwater extraction wells, electrodes, and
temperature monitoring points completed in soils within the treatment
volume
¦ Groundwater - collect samples in treatment zone monthly during treatment
operations
¦ Air/Vapor - collect weekly to evaluate when the remedy is nearing a point of
diminishing return in terms of NAPL, aqueous phase COCs, and vapor
extraction and treatment
¦ Vapor Control (Pneumatic Vacuum Pressure) - monitor with vapor pressure
gauges to check on controlling and capturing vapors, steam, and air in the
subsurface soil in order to prevent migration of vapors, steam, and air from
the treatment area
The primary purpose of this technology is to aggressively remove mass from what is
believed to be a main source area. This conceptual design provides for a 92%
reduction in mass in the treatment zone and a heating period of approximately six
months. For cost estimating purposes, annual monitoring for VOCs at ten wells in
and near this treatment zone will continue for 30 years after the heating period is
ended.
This alternative should be combined with an alternative for shallow soil and filter
cake or the ERH treatment zone should be extended vertically to include the shallow
soil and filter cake. If it is not, then contamination from the shallow zone will
recontaminate the treated soils. Also, if the alternative is combined with an
aggressive treatment option for high concentration groundwater (generally areas to
the south and southwest) the mass removed from the groundwater system and the
contaminant flux reduction will be substantial. Contaminant flux measurements are
discussed in Section 4.2.3.
Increasing the biodegradation rates in groundwater that is warmed outside of the
treatment zone has been shown to be a secondary benefit of ERH. Therefore,
biodegradation rates may increase in downgradient areas (e.g., underneath the Time
CDM
Well 12A Final FFS April 2009
4-5
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Oil Building). However, due to limited research in this area, this secondary benefit
was not evaluated.
ERH is the ITR technology proposed for the site in this FFS. Other methods
(conduction and steam injection) are also available, but their application does not
seem to meet site requirements. Conduction is generally more appropriate for
shallower and smaller contaminant volumes and the cost of the steam technology is
typically considered higher than ERH. However, if groundwater fluxes are elevated,
steam may have some advantages over ERH. During this FFS an ERH contractor was
provided the site information and that contractor believes ERH is applicable.
However, if conditions are found to be different (e.g., higher groundwater flux) than
estimated in this FFS, then a different ITR technology (e.g., steam) may be considered.
4.2.3 High Concentration Groundwater
High concentration groundwater is identified as TCE or cis-l,2-DCE concentrations
greater than 300 (ig/L.
4.2.3.1 Alternative HG1 - No Action
The no action alternative is considered in accordance with NCP requirements and
provides a baseline for comparison with the other alternatives. No further action
would be conducted and the status of the site groundwater would remain unchanged.
The GETS would be shut down. This alternative does not include the implementation
of any institutional controls such as deed restrictions or future groundwater
monitoring. CERCLA (Section 121(c)), as amended by SARA (1986), would require
that the site be reviewed every 5 years, because contamination would remain on site.
4.2.3.2 Alternative HG2 - Institutional Controls
ICs would be employed to protect human health. The ICs would be used in limiting
access to future development, improvement, and use of affected properties.
Specifically, ICs would include activity and use restrictions enacted through
proprietary (e.g. easements, covenants) and/or governmental (e.g. zoning
requirements) controls to prevent use of the property that would pose an
unacceptable risk to receptors (i.e. for residential use). Tacoma-Pierce County Board
of Health Resolution No. 2002-3411, Land Use Regulations and applicable sections of
Washington Administrative Code Titles 173 and 246 are current guidelines that
would be considered, or possibly amended, for the location and installation of supply
wells. Additional details regarding potential institutional controls associated with
Tacoma Water's use of groundwater from the South Tacoma well field are presented
in Section 4.2.4.2. Informational device ICs (warning signs, advisories, additional
public education) also would be employed to limit access to contaminated
groundwater. The GETS would be shut down. An additional component of this
alternative involves the continued monitoring of groundwater at the site. For cost
estimating purposes, it was assumed that 20 wells will be monitored for VOCs for a
period of 30 years.
CDM
Well 12A Final FFS April 2009
4-6
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
In accordance with CERCLA, this alternative would be evaluated at least every five
years because contaminants would remain on site with this alternative.
4.2.3.3 Alternative HG3 - Extraction and Treatment with GETS
This alternative is for the operation and maintenance of the existing GETS. It does not
include system replacement if the life cycle of the treatment plant is reached. The
extraction system originally consisted of a single extraction well (EW-1) designed to
extract water at 500 gpm. While a maximum sustained pumping rate of
approximately 300 gpm was achieved in this well during 1988, the maximum
sustained pumping rate decreased steadily to approximately 50 gpm in 1999. To
augment EW-1, four additional extraction wells were installed in 1995. While the
design yield of each of these wells was 50 gpm, each well only produces
approximately 10 gpm; the total extraction rate of the five wells is approximately 100
gpm. The treatment system is located outside on a concrete pad surrounded by a
chain-link fence. The system consists of two bag filters arranged in parallel that
precede two 20,000-pound GAC units arranged in series. Effluent from the second
carbon unit is discharged to the Thea Foss Waterway via storm drains.
Although the system has been operating for 20 years, substantial contaminant mass
still remains in the soil and groundwater. However, a capture zone analysis indicates
that the GETS provides hydraulic control although the capture zone extent is
uncertain in some areas. Continuing to operate the GETS will limit the migration of
contaminants away from the site.
The GETS will be used to maintain hydraulic control and treat contaminated
groundwater. If no other aggressive actions are taken to reduce contaminant mass,
the GETS may need to continue to operate ad infinitum to maintain hydraulic control.
Therefore, the duration of this alternative was assumed to be 30 years.
4.2.3.4 Alternative HG4 - Enhanced Anaerobic Bioremediation
This alternative consists of in situ treatment of contaminated groundwater through
enhanced anaerobic biological treatment. TCE and cis-l,2-DCE could be effectively
biodegraded through reductive dechlorination under anaerobic conditions. The MNA
results indicate that the groundwater in the high concentration zone is anaerobic, but
a carbon food source for cometabolic degradation has been depleted. Therefore, the
delivery of an amendment will jump start the anaerobic degradation process. Case
histories suggest that contaminant concentration reductions of more than 80% may be
experienced. A mass balance calculation could be performed; however, the estimate
would have significant uncertainty since the subsurface chemistry is very complex.
Therefore, the calculation would not have much meaning and was not performed.
Figure 4-2 presents the selected distribution of wells to be installed to deliver the
amendment. The wells are aligned such that amendment will be delivered into the
subsurface and travel through the treatment zone following the hydraulic gradient.
Five rows of wells are proposed so that amendment is distributed with the varying
hydraulic gradient directions. This technique establishes proper conditions for
CDM
Well 12A Final FFS April 2009
4-7
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
microbial degradation while taking advantage of the groundwater flow velocities and
gradients.
Commercially available electron donors come in both solid and liquid forms and vary
considerably with respect to longevity. Available placement techniques include
direct-push, trenching, injection wells, and fracturing. Based on the size and depth of
the plume at this site, directly injecting an emulsified soybean oil-based substrate,
EOS™, was selected for this FFS. Various options would be evaluated based on
results from the pre-design investigation and a phased approach would be
implemented during the remedial action.
The optimal well spacing within each row depends on a variety of factors including
formation, drilling costs, amendment costs, desired injection period, and the vertical
treatment zone thickness. Based on 35-foot injection well spacing, 34 injection wells
are needed. A 35 foot spacing (ROI of approximately 18 ft) is expected to be achieved
in the hydrogeologic conditions. A short term pilot injection test should be conducted
prior to full scale implementation to confirm the optimal ROI.
The injection wells, with a depth of approximately 100 ft, would be constructed with
2-inch diameter schedule 40 PVC, and screened in the lower 60 feet (approximate
aquifer thickness) of the installation. It is assumed that they would be installed via
hollow stem auger (HSA) rig without sampling other than bulk soil cuttings to
confirm disposal options. The wellheads would be modified for hose fittings and
finished with a simple flush mounted casing.
Amendment Injection
Once the injection wells have been installed, the initial injection event would occur
one row at a time. The viscosity of EOS™ solution is temperature sensitive, therefore
injections should occur during warm weather. Also, EOS™ is expected to adhere to
soil particles; therefore, allowing some diffusion to occur into low velocity
environments. Temporary aboveground piping and hoses would be used to
distribute the amendment to the injection wells. For the cost estimate of this FFS, it is
assumed that a trailer mounted distribution system would be constructed for injection
to all the wells in a given row simultaneously, and two water trucks would be used to
transport potable water from a metered hydrant.
Once injection to all rows of wells has been completed, the temporary injection
equipment would be removed and no activity would be required other than periodic
groundwater monitoring for one year. It is assumed that an additional full-scale
injection event would take place approximately 18 months after the first injection.
Enhanced Anaerobic Bioremediation Performance Monitoring
Eight new monitoring wells plus 10 existing wells will be monitored to track the
progress of the remedy. Six of the new wells will be installed along the proposed flux
measurement line and two wells (in the shallow aquifer in upper and lower depths)
will be installed in the VOC plume south and east of South Tacoma Way. Well
locations would be selected to allow for monitoring conditions both inside the plume
CDM
Well 12A Final FFS April 2009
4-8
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
and along the edges, which would address concerns for lateral movement of the
amendment.
The required analyte list would include: CVOCs, ethene, ethane, methane, sulfate,
iron, alkalinity, total organic carbon, and water quality parameters (DO, conductivity,
temperature, oxidation reduction potential (ORP), and pH). While it is assumed that
the EOS™ product will maintain desired carbon levels for at least 3 years (i.e., about
two times longer than the currently estimated injection interval of 18 months), the
results from the monitoring program would be the basis for determining if and when
a second injection is necessary. Quarterly sampling is assumed for the first year, with
the frequency reduced to twice a year thereafter. Monitoring will continue at 18 wells
for 30 years.
Flux Measurement
In addition to the performance monitoring described above, passive flux meters will
be used to measure contaminant flux. Figure 4-2 shows the wells to be used to
measure flux. A passive flux meter is a self-contained permeable unit that is inserted
into a well and provides depth discrete measurement of contaminant flux. The meter
intercepts groundwater flow but does not retard it. The interior composition of the
flux meter is a matrix of hydrophobic and hydrophilic permeable sorbents that retain
dissolved organic and/or inorganic contaminants present in fluid intercepted by the
unit. The sorbent matrix is also impregnated with known amounts of one or more
fluid soluble 'resident tracers.' These tracers are leached from the sorbent at rates
proportional to fluid flow, which allows contaminant flux to be estimated.
The passive flux meter test involves collecting and analyzing data in a series of wells
to estimate the mass flux at the well line. The technique is passive and requires no
purging or pumping at the well and, therefore, produces a relatively small amount of
sampling derived waste. Because passive flux meters can be deployed at multiple
vertical locations in each well, the vertical distribution of contaminant concentrations
and groundwater flow rate at the wells can be measured. The Darcy flux at each well
is also estimated as part of the testing method concurrent with estimating the
contaminant mass flux.
Baseline flux measurement will be collected prior to implementing any remedial
action. The baseline measurements will be collected
¦ while the GETS is operating
¦ while the GETS is not operating (ambient conditions)
Estimating flux under these two conditions is recommended so that the impact of the
groundwater extraction operations on flux can be assessed. Converging lines of
evidence suggest the capture zone developed by the GETS is near the east (between
WCC-6 and WCC-2) and southwest (between WCC-3 and proposed cluster MW-
309/310) sections of the flux measurement plane. Understanding the flux estimates
under the two scenarios will provide a measure of groundwater extraction impacts on
flux and will assist in delineating the extent of the capture zone, which is especially
CDM
Well 12A Final FFS April 2009
4-9
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
important near the east and southwest ends of the flux plane. Lastly, when flux is
being measured in both scenarios, a synoptic round of groundwater levels will be
collected from all site wells. The water levels will be used to estimate the direction of
groundwater flow at the flux plane and across the site.
Presently, the first flux measurement event (after the baseline measurement event) is
estimated to occur approximately 18 months after the first remedial activity is
completed. The flux measurements are proposed to be measured while the GETS is
operating. An 18 month period is proposed since the longest travel time from a
proposed treatment location to a proposed flux measurement well is approximately
18 months. This estimate is based on the travel time from the south edge of South
Tacoma Way (a proposed location to receive enhanced bioremediation amendment)
to proposed flux measurement wells MW-311 and 312 (220 feet) using a retarded TCE
velocity of 0.42 ft/ day
220 ft/ (0.42 ft/ day) = 524 days (approximately 18 months)
This value may be revised based on observations or changes (e.g., the repositioning of
amendment injection locations due to access issues) made during design. These
measurement intervals may be revised based on contaminant concentration trends in
the treatment zones using results from monitoring well sampling activities conducted
concurrently with the flux measurements. For example, if concentrations are
considerably reduced such that the flux goal will be clearly met, then the frequency of
flux measurements may be reduced. Conversely, if concentrations are persistent, then
the frequency of flux measurements may be increased. For the purpose of cost
estimating, five flux measurements at twelve wells will be made over a six year
period. The cost includes the installation of the six new flux measurement wells. Two
wells will be completed to a depth of 50 ft and four wells will be installed to a depth
of 100 ft.
GETS Operation
This alternative includes the operation of the GETS to maintain hydraulic control
while mass is reduced via EAB. Operation of the GETS will be terminated when it is
shown that site COC concentrations have been reduced and the mass flux of COCs
through the proposed plane meets the RAO. The GETS will operate during the EAB
injection (assume three year period) and an estimated two years after the second
injection is made. Therefore, the GETS is assumed to need to be operated and
maintained for five years.
4.2.3.5 Alternative HG5 - Air Sparging and Soil Vapor Extraction
This alternative uses in situ air sparging (AS) coupled with SVE to remove volatile
organics from the groundwater. The location of the AS/SVE wells are proposed for
the area west of the Time Oil Building. From 1993 to 1997 an SVE system was
successfully operated in this area; VOC soil concentrations have decreased but VOC
groundwater concentrations remain elevated. The AS/SVE well locations are shown
on Figure 4-3.
CDM
Well 12A Final FFS April 2009
4-10
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
This alternative has been retained since the SVE system operated in the 1990s was
very successful at removing VOCs. However, significant data have been collected to
demonstrate that anaerobic reductive dechlorination is a significant degradation
pathway. Therefore, the operation of an AS/SVE system would introduce oxygen
into the subsurface, which would counteract the benefits of the existing anaerobic
conditions. The AS/SVE alternative is proposed in a small portion of the high
concentration plume west of the former Time Oil building, but EAB is proposed for
most of the rest of the plume. Existing SVE equipment and wells are at the site.
However, since the equipment has not been used in more than ten years and a
cursory inspection of the equipment revealed that it is in poor condition, the
equipment was assumed to be unusable for this estimate. However, if the alternative
is selected, a detailed inspection and evaluation can be performed in the design to
determine if any of the equipment (including wells) is usable.
AS is a groundwater remediation technology that involves the injection of air under
pressure into a well installed within the groundwater plume. Air sparging
technology extends the applicability of SVE to saturated soils and groundwater
through physical removal of volatilized groundwater contaminants. Generally, AS is
more effective for contaminants with greater volatility and lower solubility and for
soils with higher permeability. Therefore, it is well suited for the treatment of the
main CVOCs found at the site. The rate at which the contaminant mass is removed
decreases as AS operations proceed and concentrations of dissolved contaminants are
reduced.
Air injected below the water table volatilizes aqueous phase contaminants in
groundwater. The volatilized contaminants migrate upward to the vadose zone,
where they are removed using SVE. With SVE, a vacuum is applied to the
contaminated soil matrix through extraction wells. This creates a negative pressure
gradient in the unsaturated zone that causes movement of vapors toward these wells.
The extracted vapors are then treated, as necessary, and discharged to the
atmosphere.
Air sparging systems can be designed with air flow rates and pressures to provide
adequate coverage of the area of contamination, but need to minimize the potential
for uncontrolled releases of contaminated vapors to the atmosphere, into houses or
industrial buildings. Other air sparging systems can be utilized in a barrier type of
alignment, referred to as a sparge curtain. Off-gas treatment is expected to be
required given the high VOC concentrations and proximity of homes and industrial
buildings.
Field pilot studies will be necessary to adequately design and evaluate the system.
The most important design parameter to be considered for the air sparging system is
the radius of influence. This radius is the greatest distance from a sparging well at
which sufficient sparge airflow can be induced to enhance the mass transfer of
contaminants from the aqueous phase to the vapor phase. The radius of influence
will determine the number and spacing of the sparging wells that are required, with
an overlap in their radii of influence so that the contamination area is covered. The
CDM
Well 12A Final FFS April 2009
4-11
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
sparging air flow rate required to provide sufficient air flow to enhance mass transfer
is site-specific and will be determined during the pilot test phase. These studies will
also help to determine if hydraulic controls may be necessary to control possible
plume migration or enhance flows through sparge curtains.
At the Well 12A site, it is envisioned that the sparging wells will be placed on 50-foot
centers across the high concentration groundwater plume west of the Time Oil
Building. This will require a total of five sparging wells. The air sparging wells will
be placed at 100 feet bgs, which is at the top of the semi confining unit, approximately
65 ft below the water table. In the same area as the sparging wells, ten SVE wells will
be placed above the shallow aquifer (approximately 30 feet bgs) to capture any
volatilized compounds that are forced out of the vadose zone by the sparging process.
One sparge well and two vapor extraction wells are proposed to be installed at an
angle to reach underneath the Time Oil building. It is estimated that the AS/SVE
system will operate for a period of five years. Thereafter, monitoring in the treatment
zone would occur for a two year period.
GETS Operation
This alternative includes the operation of the GETS to maintain hydraulic control
while mass is reduced via AS/SVE and EAB. Operation of the GETS will be
terminated when it is shown that site COC concentrations have been reduced and the
mass flux of COCs through the proposed plane meets the RAO. The GETS will
operate during the EAB injection (assume three year period) and an estimated two
years after the second injection is completed. Therefore, it is assumed that the GETS
will need to be operated and maintained for eight years.
4.2.4 Low Concentration Groundwater
This zone extends from the high concentration zone to the three conditional points of
compliance wells: Well 12A, and proposed compliance wells 1 and 2.
4.2.4.1 Alternative LG1 - No Action
The no action alternative is considered in accordance with NCP requirements and
provides a baseline for comparison with the other alternatives. No further action
would be conducted and the status of the site groundwater would remain unchanged.
The air stripping towers at Well 12A would not be operated. This alternative does not
include the implementation of any institutional controls such as deed restrictions or
future groundwater monitoring. CERCLA (Section 121(c)), as amended by SARA
(1986), would require that the site be reviewed every 5 years, because contamination
would remain on site.
4.2.4.2 Alternative LG2 - Wellhead Treatment at Well 12A
In 1983 five air stripping towers were installed to treat the discharge water at Well
12A. Tacoma Water has operated and maintained the towers since their installation.
This alternative includes the continued O&M of the five air stripping units and
monitoring groundwater for VOCs at Well 12A. For cost estimating purposes, it was
assumed that the O&M would continue for a period of 30 years.
CDM
Well 12A Final FFS April 2009
4-12
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
As part of the wellhead treatment alternative, an IC plan would be developed and ICs
would be employed to protect human health. The ICs would be used to limit access
to and future development, improvement, and use of affected properties. Specifically,
ICs would include activity and use restrictions enacted through proprietary (e.g.
easements, covenants) and/or governmental (e.g. zoning requirements) controls to
prevent use of the property that would pose an unacceptable risk to receptors (i.e. for
residential use). Tacoma-Pierce County Board of Health Resolution No. 2002-3411,
Land Use Regulations and applicable sections of Washington Administrative Code
Titles 173 and 246 are current guidelines that would be considered, or possibly
amended, for the location and installation of supply wells.
Additional ICs may include temporary operational guidelines and/ or restrictions on
Tacoma Water's use of the South Tacoma Well Field; however, the plan would also set
forth communication and evaluation procedures for any required or proposed
deviations from the plan. These guidelines and/ or restrictions are expected to be
similar to the informal pumping strategy currently used by Tacoma Water, but the
procedures would be formalized in the IC plan. The plan would be developed during
the remedial design and would set forth operational guidelines, restrictions, and
procedures to ensure protection of human health for the duration of the remedy.
Informational device ICs (warning signs, advisories, additional public education) also
would be employed to limit access to contaminated groundwater. A health and safety
plan would be developed and implemented to protect workers from contact to
groundwater contaminants.
This alternative makes use of new and existing monitoring wells to perform long-term
monitoring of groundwater contamination. Wells installed in the upper and lower
aquifers will be monitored for VOCs. Also, half of the wells will be monitored for
ethene, ethane, methane, sulfate, iron, alkalinity, total organic carbon, and water
quality parameters (DO, conductivity, temperature, oxidation reduction potential
(ORP), and pH). Two new wells will be installed in the shallow aquifer southeast of
South Tacoma Way in the area where the extent of TCE contamination is uncertain.
For evaluation purposes, it is estimated that 20 monitoring wells would be included in
the sampling program for a long-term monitoring period of 30 years.
In accordance with CERCLA, this alternative would be evaluated at least every five
years because contaminants would remain on site.
Presently, VOC concentrations at interim monitoring points (in this example CH2M-2)
are expected to decrease to below the MCLs after the second EAB injection is made in
the high concentration groundwater treatment zone. The second injection event will
occur approximately 18 months after implementing the action. The time for the
treated groundwater to be detected at CH2M-2 after the second treatment is estimated
to be three years plus the travel time from the injection point line to the well (a
distance of approximately 600 ft):
¦ 3 years + 600 ft/ (0.42 ft/ day x 1 yr/365 days) = 7 years
CDM
Well 12A Final FFS April 2009
4-13
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
This estimate is based on current hydraulic conditions. If additional data are collected
(e.g., higher hydraulic conductivity that provides a more direct pathway to the well)
the estimate may change. Also, if pumping conditions change (e.g., Well 12A increase
production) the estimate may change. Increases in withdrawal at Well 12A may
decrease the travel time to CH2M-2, since more flow would be occurring from the
Time Oil property to the production well (i.e., away from CH2M-2). If withdrawal is
for six months rather than the estimated three months, the velocity may be reduced
by one-half 0.42 ft/day to 0.21 ft/ day. Therefore, impacts may be seen in 14 years
(twice seven years). These estimates provide a general concept of travel times.
However, the aquifer and withdrawal scenarios are very complex and travel times
will vary. Therefore, measuring Darcy velocity with the GETS on and off, which is
proposed, will be an important component of the remedy.
4.3 Evaluation Criteria
EPA has outlined nine evaluation criteria to be used in assessing remedial alternatives
in the NCP which take into consideration the statutory requirements specified in
Section 121 of the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 as amended by the Superfund Amendments and Reauthorization
Act of 1986. In addition, EPA has issued additional guidance on the evaluation
criteria in "Guidance for Conducting Remedial Investigations and Feasibility Studies
Under CERCLA" (EPA, 1998). The criteria are classified into the following three
groups.
Threshold Criteria. The threshold criteria are requirements that each alternative
must meet in order to be eligible for selection.
¦ Overall Protection of Human Health and the Environment
¦ Compliance with ARARs (unless waived)
Primary Balancing Criteria. These criteria are used to distinguish the relative
effectiveness of each alternative so that decision makers can evaluate the strengths
and weaknesses of each alternative.
¦ Long-term Effectiveness and Permanence
¦ Reduction of Toxicity, Mobility, or Volume Through Treatment
¦ Short-term Effectiveness
¦ Implementability
¦ Cost
Modifying Criteria. These factors are typically considered following review of this
document and the Proposed Plan by the regulatory agencies and the public, and are
formally documented as part of the ROD Amendment. These criteria are not
evaluated in this FFS.
¦ Support Agency (Washington Department of Ecology for this site)
Acceptance
CDM
Well 12A Final FFS April 2009
4-14
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
¦ Community Acceptance
Brief discussions for each of the above criteria are provided below.
¦ Overall Protection of Human Health and the Environment - This criterion
assesses each alternative's ability to provide adequate protection of human
health and the environment, and describes how site risks associated with
each exposure pathway are eliminated, reduced, or controlled, through
treatment, engineering, and/or institutional controls.
¦ Compliance with ARARs - Alternatives are assessed as to whether they
attain legally applicable or relevant and appropriate requirements of Federal
and State requirements, standards, criteria, and limitations which are
collectively referred to as "ARARs," unless such ARARs are waived under
CERCLA section 121(d)(4).
¦ Long-term Effectiveness and Permanence - This criterion considers the
ability of an alternative to maintain reliable protection of human health and
the environment over time. The evaluation takes into account the residual
risk remaining on site at the conclusion of remedial activities, as well as the
adequacy and reliability of containment systems and institutional controls.
¦ Reduction of Toxicity, Mobility, or Volume Through Treatment - This
criterion addresses the statutory preference for selecting remedial actions that
employ treatment technologies that permanently and significantly reduce the
toxicity, mobility, or volume (T/M/V) of the hazardous substances as their
principal element. This criterion evaluates the anticipated performance of the
treatment technologies that may be included as part of a remedy.
¦ Short-term Effectiveness - Short-term effectiveness addresses the period of
time needed to implement the remedy and any adverse impacts that may be
posed to workers, the community, and the environment during construction
and operation of the remedy until cleanup levels are achieved.
¦ Implementability - This criterion addresses the technical and administrative
feasibility of implementing a remedy from design through construction and
operation. Factors such as the availability of services and materials and
coordination with other governmental entities are considered.
¦ Cost - An estimate of the cost for each alternative is determined so that the
cost can be compared to the level of protectiveness that each alternative
provides. The typical cost estimate made during the FFS is intended to
provide an accuracy of +50 percent to -30 percent, as discussed in the EPA
RI/FS guidance document. The types of costs that are assessed include the
capital costs, operation and maintenance (O&M) costs, and present worth.
CDM 4-15
Well 12A Final FFS April 2009
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
o Capital Costs - The capital costs include both the direct and indirect
capital costs required to implement the remedial action. Direct
costs are comprised of construction costs for equipment, labor,
materials, transportation, and disposal. Indirect costs include those
associated with permitting and legal, engineering, services during
construction, and contingencies.
o O&M Costs - These costs include labor and materials associated
with operation and maintenance following the remedial action,
such as operating a pump-and-treat system, long-term monitoring
costs, or 5-year site reviews. The EPA RI/FS guidance document
recommends that O&M costs not be determined for longer than 30
years.
o Present Worth - The present worth of the capital and O&M costs is
determined to evaluate expenditures that occur over different time
periods so that the costs for remedial alternatives can be compared
on the basis of a single figure. The present worth has been
calculated based on Federal policy which recommends assuming a
7% discount rate.
¦ Support Agency (State) Acceptance - Support agency acceptance is typically
considered following review of this document and the Proposed Plan by the
regulatory agencies, and is formally documented as part of the ROD
Amendment.
¦ Community Acceptance - The preferred remedy will be presented to the
public in the Proposed Plan. Issues raised by the community will be
discussed in the Responsiveness Summary of the ROD Amendment, which
will respond to public questions and concerns on the FFS and Proposed Plan.
4.4 Individual Analysis of Alternatives
In this section, the alternatives are assessed on the basis of the evaluation criteria
described in Section 4.3. Descriptions of each alternative are provided in Section 4.2.
4.4.1 Filter Cake and Shallow Impacted Soil
This zone is located east of the Time Oil Building and extends to a depth of 10 ft bgs.
4.4.1.1 Alternative FC1 - No Action
Overall Protection of Human Health and the Environment
No action would not be protective of human health and the environment. Filter cake
and shallow soil that is contaminated with COCs at concentrations exceeding MTCA
B-modified levels will remain at the site. Direct contact with these materials by
tenants or trespassers and excavation or trenching activities would pose a risk. In
addition, the contamination would continue to provide a source to groundwater.
CDM
Well 12A Final FFS April 2009
4-16
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
The No Action Alternative fails to meet this threshold criterion of protectiveness and,
therefore, will not be evaluated further.
4.4.1.2 Alternative FC2 - Institutional Controls
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health through access
restrictions. Long-term soil monitoring would be performed to track contaminant
levels over time.
Compliance with ARARs
This alternative would not achieve chemical-specific ARARs (soil MTCA levels)
established for the contaminated soils. Action-specific ARARs would not apply to
this alternative since further remedial actions would not be conducted.
Long-Term Effectiveness and Permanence
This alternative would not provide long-term effectiveness and permanence. The
long-term monitoring program would be used to track contaminant persistence and
potential migration. The potential for future human exposure would be minimized
through the implementation of restrictions forbidding or limiting areas where digging
would be allowed. The continued exposure of onsite receptors to surface soil would
be a potential long-term impact of this alternative and remediation goals derived for
protection of human health would not be met. Because contaminated material would
remain on site under this alternative, a review/reassessment of the conditions at the
site would be performed at 5-year intervals to ensure that the remedy would not
become a greater risk to human health and the environment.
Reduction of T/M/V Through Treatment
No reductions in contaminant T/M/V would be realized under this alternative.
Short-Term Effectiveness
No construction activities would be associated with this alternative so no risks to
construction workers would occur from implementation. There would be minimal
exposure risk to personnel during sampling activities associated with the long-term
monitoring program, which would continue for 30 years. Every five years, an
evaluation would be performed to determine whether the remedy would be
protective and whether long-term monitoring should be continued or whether
additional remedial action would be necessary. However, there are no impacts
because no action is taken and protection is not achieved.
Implementability
This alternative would be easily implemented. Minimal administrative tasks would
be involved with the long-term monitoring program and minimal services and
materials would be required. This alternative would require the state or local
government to secure restrictions on digging at all affected areas as well as the
implementation of proprietary controls.
CDM
Well 12A Final FFS April 2009
4-17
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $30,600
¦ Annual O&M Cost: $39,000
¦ Present Worth: $114,800
4.4.1.3 Alternative FC3 - Capping Contaminated Soils In Place
Overall Protection of Human Health and the Environment
Capping contaminated soils in place would eliminate exposure pathways and
significantly reduce the level of risk at the Well 12A Site. The implementation of ICs
such as deed restrictions and asphalt cap maintenance requirements would limit
exposure to contaminated soils remaining on site.
Compliance with ARARs
Because contamination will remain in place, ICs would be required to comply with
MTCA's 15 ft point of compliance for the direct contact human exposure pathway.
Long-Term Effectiveness and Permanence
This alternative would provide long-term effectiveness and permanence by capping
contaminated soils and minimizing the potential for future human exposure through
the implementation of ICs restricting future digging in the area and maintenance of
the cap. Because contaminated material would remain on site under this alternative, a
review/ reassessment of the conditions at the site would be performed at 5-year
intervals to ensure that the remedy would not become a greater risk to human health
and the environment.
Reduction of T/M/V Through Treatment
Capping the contaminated soil at the site would reduce the mobility since the cap will
prevent (or significantly minimize) infiltration of precipitation. Toxicity and volume
of the contaminants that remain under the cap will not be reduced.
Short-Term Effectiveness
During placement of the cap, Level D personnel protective equipment would be
required. Grading may result in release of nuisance or contaminated dust. Use of
heavy equipment may cause a noise nuisance. Engineering controls would be utilized
for controlling the dust. Higher levels of personnel protection may become necessary
for onsite workers during activities if engineering controls do not reduce dust or
noise.
CDM
Well 12A Final FFS April 2009
4-18
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Implementability
This alternative would have minimal technical considerations as long as asphalt
remains readily available. This alternative would require implementation of ICs to
ensure the cap is maintained and that digging below the cap is restricted.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $798,100
¦ Annual O&M Cost: $75,400
¦ Present Worth: $1,267,300
4.4.1.4 Alternative FC4—Excavation of Soils, Transportation to and Disposal
in RCRA Subtitle C or D Landfill
Overall Protection of Human Health and the Environment
Excavating contaminated soil and transporting it to an offsite RCRA-permitted
landfill for disposal would eliminate exposure pathways and significantly reduce the
level of risk at the Well 12A Site. The implementation of ICs such as deed restrictions
and limits on digging would reduce exposure to contaminated soils remaining on site.
Compliance with ARARs
Transportation of contaminated soil would be in accordance with applicable
Department of Transportation hazardous material regulations. Disposal at a RCRA
permitted landfill would be in compliance with ARARs. For areas where
contaminated soils remain, either additional in situ treatment would be performed or
ICs would be used to further reduce the potential for exposure and achieve
compliance with MTCA's 15 ft point of compliance for the direct contact human
exposure pathway.
Long-Term Effectiveness and Permanence
This alternative would provide long-term effectiveness and permanence by removing
contaminated soils. Where contaminated soils remain, the potential for future human
exposure would be minimized through the implementation of engineering controls
and restrictions forbidding or limiting areas where future digging would be allowed.
Because contaminated material would remain on site under this alternative, a review/
reassessment of the conditions at the properties where contamination would still be
present would be performed at 5-year intervals to ensure that the remedy would not
become a greater risk to human health and the environment.
Reduction of T/M/V Through Treatment
Removal of the contaminated soil would reduce the mobility and volume of the waste
at the site because the material would be excavated and transferred to the disposal
location. The toxicity would be removed from the site, with the final toxicity
CDM
Well 12A Final FFS April 2009
4-19
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
contingent upon the disposal methods. Disposal in a landfill would not reduce
toxicity.
Short-Term Effectiveness
During onsite removal actions Level D personnel protective equipment would be
required. The potential exists for a higher level of protection to be used during
excavation or loading of trucks. Excavation and grading may result in release of
nuisance or contaminated dust. Use of heavy equipment may cause a noise nuisance.
Engineering controls would be utilized for controlling the dust. Higher levels of
personnel protection may become necessary for onsite workers during activities if
engineering controls do not reduce dust, or noise.
Implementability
This alternative has minimal technical considerations except for the need to ensure
structural stability while digging near building foundations. Representative soil
samples would be collected and presented to the receiving landfill(s) for their
acceptance evaluation, and providing requirements specified in 40 CFR 268.30 are
met. Historical knowledge and current information about soil chemical and physical
characteristics would be provided to the landfill(s). The available data suggest that the
excavated soils could be disposed in a Subtitle D landfill.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $2,346,500
¦ Annual O&M Cost: $68,900
¦ Present Worth: $2,801,700
4.4.2 Deep Vadose Zone Soil and Upper Saturated Zone East of
Time Oil Building
This zone lies east of the Time Oil Building and extends to a depth of 55 ft bgs.
4.4.2.1 Alternative SGI - No Action
Overall Protection of Human Health and the Environment
No action would not be protective of human health and the environment. Soil that is
contaminated with COCs at concentrations exceeding MTCA B-modified levels will
remain at the site. Direct contact with these materials by tenants or trespassers and
excavation or trenching activities would pose a risk. In addition, the contamination
would continue to provide a source to groundwater. The status of the upper saturated
zone groundwater would remain unchanged. This alternative does not include the
implementation of any institutional controls such as deed restrictions or future
groundwater monitoring. CERCLA (Section 121(c)), as amended by SARA (1986),
would require that the site be reviewed every 5 years, because contamination would
remain on site.
CDM
Well 12A Final FFS April 2009
4-20
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
The No Action Alternative fails to meet this threshold criterion of protectiveness and,
therefore, will not be evaluated further.
4.4.2.2 Alternative SG2 - Institutional Controls
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health by restricting site access
and the installation of new wells. Long-term soil and groundwater monitoring would
be performed to track contaminant levels over time.
Compliance with ARARs
This alternative would not achieve chemical-specific ARARs (e.g., soil MTCA levels)
or RAOs (mass reduction) established for the contaminated soils. Action-specific
ARARs would not apply to this alternative since further remedial actions would not
be conducted.
Long-Term Effectiveness and Permanence
This alternative would not provide long-term effectiveness and permanence. The
long-term monitoring program would be used to track contaminant persistence and
potential migration. The potential for future human exposure would be minimized
through the implementation of restrictions forbidding or limiting areas where digging
would be allowed and wells installed. The continued exposure of onsite receptors to
soil would be a potential long-term impact of this alternative and remediation goals
derived for protection of human health would not be met. Because contaminated
material would remain on site under this alternative, a review/reassessment of the
conditions at the site would be performed at 5-year intervals to ensure that the
remedy would not become a greater risk to human health and the environment.
Reduction of T/M/V Through Treatment
No reductions in contaminant T/M/V would be realized under this alternative.
Short-Term Effectiveness
No construction activities would be associated with this alternative so no risks to
construction workers would occur from implementation. There would be minimal
exposure risk to personnel during sampling activities associated with the long-term
monitoring program, which would continue for 30 years. Every five years, an
evaluation would be performed to determine whether the remedy would be
protective and whether long-term monitoring should be continued or whether
additional remedial action would be necessary. However, there are no impacts
because no action is taken and protection is not achieved.
Implementability
This alternative would be easily implemented. Minimal administrative tasks would
be involved with the long-term monitoring program and minimal services and
materials would be required. This alternative would require the state or local
CDM
Well 12A Final FFS April 2009
4-21
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
government to secure restrictions on digging at all affected areas as well as the
implementation of proprietary controls.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $30,600
¦ Annual O&M Cost: $39,000
¦ Present Worth: $114,800
4.4.2.3 Alternative SG3 - In situ Thermal Remediation
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health and the environment by
reducing the mass of VOC contamination in this zone. A goal of 90% mass reduction
has been assigned. Reducing the mass would, in effect, remove the source area so
that downgradient concentrations would decrease at a more rapid rate. Therefore, the
alternative is protective of human health and the environment due to the reduction in
mass.
Compliance with ARARs
The first tier goal is to aggressively destroy contaminant mass. One benefit of mass
destruction is that it results in reduced concentrations in soil and in groundwater in
the treatment zone. Theoretically, the soil and groundwater concentrations could
decrease to below MTCA and MCL levels, respectively, in some areas. However, the
primary goal is to achieve a mass reduction of at least 90%; reductions to below
health-based standards would be a secondary benefit. Therefore, the alternative
complies with the RAOs, but it may not achieve compliance with chemical-specific
ARARs within the treatment zone boundary. Compliance with chemical-specific
ARARs will be measured at the proposed compliance well locations. The MTCA soil
levels and groundwater MCLs may not be achieved within the 30-year evaluation
period; however, this remains a long-term goal. Residual impacts exceeding MTCA
cleanup levels and MCLs will be addressed via ICs and ongoing wellhead treatment
at Well 12A.The heat treatment time is approximately six months. Decreases in mass
will be seen soon after the heating process is initiated. This alternative would be
designed to comply with location and action-specific ARARs/RAOs. Permit
equivalencies would be addressed including air limits.
Long-Term Effectiveness and Permanence
This alternative would provide long-term effectiveness and permanence. Thermal
remediation would reduce contaminant concentrations in the soil and groundwater
plume over time. This decrease would enhance existing natural processes and
institutional controls. Reductions in plume concentration and size would be tracked
by the long-term groundwater monitoring program. The potential for future
CDM
Well 12A Final FFS April 2009
4-22
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
exposure of contaminated groundwater to receptors would be minimized through the
implementation of well drilling and groundwater use restrictions in the plume area.
Reduction of T/M/V Through Treatment
ITR would reduce the toxicity and volume of contaminated soil and groundwater.
Heated VOCs would be extracted with SVE wells and the vapor treated via a GAC
system prior to discharge. The VOCs would be transferred to the carbon media,
which would be regenerated thereby permanently destroying the VOC contaminants
through thermal treatment processes. Mobility is reduced since the source is being
removed.
Short-Term Effectiveness
It is estimated that construction of the ITR treatment system could be completed
within six months of site mobilization and the ITR heating phase would last
approximately six months. Therefore, the estimated time for the mass in this source
area to be reduced by at least 90% is one year. The estimate may differ based on the
collection of additional data (e.g., if more mass is identified). Groundwater
monitoring in the zone would continue for 30 years. Every five years, an evaluation
would be performed to determine whether remedial action goals have been achieved
or whether another treatment action should occur.
Implementability
This alternative is technically and administratively implementable. Construction of
the ITR treatment system could be completed using conventional construction
equipment and services, with contractors that specialize in this innovative technology.
For cost estimating purposes, this FFS has assumed the ITR technology will be ERH.
However, if data are collected that suggest a different technology is required (e.g.,
steam), then that technology shall be used.
The implementation is suggested to be performed as a phased approach. Treatment
of VOCs in the air discharge using carbon adsorption is a proven technology and is
readily implementable.
The regulatory and permitting requirements associated with installation of electrode
and SVE wells, laying piping, constructing the treatment system, and securing
approval for air emissions are considered to be moderately administratively intensive.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $4,106,200
¦ Annual O&M Cost: $110,500
¦ Present Worth: $4,662,000
CDM
Well 12A Final FFS April 2009
4-23
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
4.4.3 High Concentration Groundwater
High concentration groundwater is identified as the plume where TCE or cis-l,2-DCE
concentrations are greater than 300 (ig/L.
4.4.3.1 Alternative HG1 - No Action
Overall Protection of Human Health and the Environment
The no action alternative is considered in accordance with NCP requirements and
provides a baseline for comparison with the other alternatives. No further action
would be conducted and the status of the site groundwater would remain unchanged.
This alternative does not include the implementation of any institutional controls such
as deed restrictions or future groundwater monitoring. CERCLA (Section 121(c)), as
amended by SARA (1986), would require that the site be reviewed every 5 years,
because contamination would remain on site.
The No Action Alternative fails to meet this threshold criterion of protectiveness and,
therefore, will not be evaluated further.
4.4.3.2 Alternative HG2 - Institutional Controls
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health by restricting site access
and the installation of new wells. Long-term groundwater monitoring would be
performed to track contaminant levels over time.
Compliance with ARARs
This alternative would not achieve chemical-specific ARARs/RAOs (e.g., 90% flux
reduction). Action-specific ARARs would not apply to this alternative since further
remedial actions would not be conducted.
Long-Term Effectiveness and Permanence
This alternative would not provide long-term effectiveness and permanence. The
long-term monitoring program would be used to track contaminant persistence and
potential migration. The potential for future human exposure would be minimized
through the implementation of restrictions forbidding or limiting areas where digging
would be allowed and wells installed. The continued exposure of receptors to
contaminated groundwater would be a potential long-term impact of this alternative
and remediation goals derived for protection of human health would not be met.
Because contaminated material would remain on site under this alternative, a
review/reassessment of the conditions at the site would be performed at 5-year
intervals to ensure that the remedy would not become a greater risk to human health
and the environment.
Reduction of T/M/V Through Treatment
No reductions in contaminant T/M/V would be realized under this alternative.
CDM
Well 12A Final FFS April 2009
4-24
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Short-Term Effectiveness
No construction activities would be associated with this alternative so no risks to
construction workers would occur from implementation. There would be minimal
exposure risk to personnel during sampling activities associated with the long-term
monitoring program, which would continue for 30 years. Every five years, an
evaluation would be performed to determine whether the remedy would be
protective and whether long-term monitoring should be continued, or whether
additional remedial action would be necessary. However, there are no impacts
because no action is taken and protection is not achieved.
Implementability
This alternative would be easily implemented. Minimal administrative tasks would
be involved with the long-term monitoring program and minimal services and
materials would be required. Existing wells would be used. This alternative would
require the state or local government to secure restrictions on digging at all affected
areas as well as the implementation of proprietary controls.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $61,300
¦ Annual O&M Cost: $52,000
¦ Present Worth: $173,500
4.4.3.3 Alternative HG3 - Extraction and Treatment with GETS
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health and the environment by
actively pumping and treating the contaminated groundwater and maintaining
hydraulic control of part of the groundwater plume. It is expected that pumping
would reduce the plume size and contaminant concentrations over time. However
the system has been operating for 20 years and substantial contaminant mass still
remains in the subsurface.
Compliance with ARARs
The alternative would include groundwater extraction and treatment to meet
chemical-specific Federal and State ARARs over time. The time required to achieve
groundwater MCLs would vary depending on whether source control measures are
implemented. Since this alternative has been operating for 20 years and substantial
mass remains in the subsurface, it is not an alternative that aggressively destroys or
removes contaminant mass, which is a primary RAO. This alternative is operated in
compliance with location and action-specific ARARs.
CDM
Well 12A Final FFS April 2009
4-25
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Long-Term Effectiveness and Permanence
This alternative does not provide long-term effectiveness and permanence. The
system has been operating for 20 years and substantial contaminant mass remains in
the subsurface. LNAPL has been observed (more than one foot of NAPL in one well
and trace amounts in several others) in wells northeast of the EWs and concentrations
of TCE between 1,000 and 2,000 (ig/L measured in wells southwest of the EWs.
Reduction of T/M/V Through Treatment
Groundwater extraction and treatment provide minimal reduction in volume of
contaminated groundwater. Toxicity is reduced; the VOCs are transferred to the
carbon media, which would be periodically regenerated thereby permanently
destroying the VOC contaminants through thermal treatment processes. The system
reduces mobility by providing capture of parts of the high concentration plume.
However, some data suggest that part of the plume has been or is being released.
Therefore, the flux reduction RAO may not be achieved.
Short-Term Effectiveness
The system is already installed so there would be no short term effectiveness issues.
Implementability
This alternative is technically and administratively implementable. The GETS is
constructed and is being operated and maintained.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $30,600
¦ Annual O&M Cost: $339,300
¦ Present Worth: $3,708,000
4.4.3.4 Alternative HG4 - Enhanced Anaerobic Bioremediation
Overall Protection of Human Health and the Environment
This alternative would provide protection of human health and the environment. It
would meet the RAOs. Contamination within the 300 (ig/L TCE and cis-l,2-DCE
contour line would be treated in situ through enhanced anaerobic bioremediation.
The remaining contaminant concentration areas (low concentration zone) could be
readily reduced through natural processes (data indicate cometabolic aerobic
degradation) in the subsurface.
The implementation of EAB includes the delivery of a considerable amount of food-
grade amendment into the groundwater. This amendment may remain in the
subsurface for years after the RAOs are achieved.
CDM
Well 12A Final FFS April 2009
4-26
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Compliance with ARARs
This alternative would meet the mass flux reduction RAO. Source removal/reduction
would need to be implemented east of the Time Oil Building so that the EAB
reduction would occur. Implementation of EAB would reduce contaminant
concentrations in the treatment area; however, compliance with chemical-specific
ARARs (reduction of CVOCs to MCLs) may not be achieved within the 30-year
evaluation period. This alternative would be designed to meet the RAO of reducing
mass flux by 90%. This mass flux reduction is necessary for management of plume
migration and is a critical step towards achieving compliance with the chemical-
specific ARARs at the proposed compliance well locations.
Long-term Effectiveness and Permanence
This action would have long-term effectiveness and permanence. Enhanced anaerobic
biodegradation, once established, would destroy the chlorinated VOC contaminants
in the subsurface, therefore reducing the risk posed by the contaminants. The
treatment would focus on the area within the 300 (ig/L TCE and cis-1,2-DCE contour
line.
The existence of relatively low permeability silt zones and clay seams would not
reduce the effectiveness of EAB, since the dechlorination conditions and bacteria
would stay in the subsurface for some time. Therefore, any contaminants diffused out
of the low permeable zones would also be treated. In addition, the concentration
reductions of contaminants in the groundwater could increase the rates of mass
transfer for contaminants out of the low permeable zones.
Reduction of T/M/V through Treatment
In situ bioremediation would reduce the toxicity and volume of contamination.
Chlorinated VOCs would be biotransformed to ethene, ethane and methane. The
intermediate product, VC, is more toxic than PCE and TCE, but accumulation of VC is
unlikely because of its ability to degrade under aerobic conditions. Downgradient
and outside of this treatment zone, aerobic conditions prevail. Intermediates, such as
DCEs and VC, would be closely monitored.
Short-term Effectiveness
Although a fairly significant amount of site work would be required for this
alternative, this type of construction is routine, as installation of bioremediation
amendment injection systems are relatively common. Because of this, the work would
be performed without significant risk to the community. Site workers would wear
appropriate PPE to minimize exposure to contamination and as protection from
physical hazards.
This alternative would have short-term impacts to the community during
construction due to the large number of injection wells that would be installed. Access
to private properties would be required for well drilling and nutrient injections.
Some traffic control would be required. There would be noise during drilling and
nutrient injections. Injection requires a large amount of water that would need to be
taken from a hydrant.
CDM
Well 12A Final FFS April 2009
4-27
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Initially, installation of injection wells and the amendment injection system would be
completed in six months. One site-wide amendment injection would be performed
within 3 months and after approximately 18 months.
Implementablility
This alternative is technically implementable. This alternative would be constructed
and implemented using conventional construction methods and equipment. The
processes that govern degradation reactions are well understood, and technical
feasibility of enhanced bioremediation has been established at numerous sites.
Despite this, bioremediation is still considered an innovative technology. As such, it
would require bench and pilot scale testing prior to implementation. In general, no
significant technical difficulties are anticipated. No difficulty in obtaining a permit for
the injection of bioremediation amendments into groundwater is anticipated.
Services and materials for implementation of this alternative are readily available.
Competitive bids can be obtained from a number of equipment vendors and
remediation contractors. No problems are anticipated for the implementation and
enforcement of the institutional controls.
Currently, the treatment zone is underneath private properties and some roadways.
Obtaining permission for access to private properties to install the injection wells and
amendment system and perform frequent visits to the system may be a challenge.
Therefore, the administrative implementation of this alternative will be more difficult
due to it being implemented in a city area. As a result, the remedial designers will
need to consult with the city engineer and private residents for the proper placement
of the injection wells in order to take into account utilities, roads and private
properties.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $2,423,900
¦ Annual O&M Cost: $408,200
¦ Present Worth: $4,217,700
4.4.3.5 Alternative HG5 - Air Sparging and Soil Vapor Extraction
This alternative is for AS/SVE west of the Time Oil Building and EAB. AS/SVE
replaces the line of EAB wells proposed west and north of the Time Oil Building in
Alternative HG4. Discussion in the subsection focuses on the AS/SVE part of the
alternative.
Overall Protection of Human Health and the Environment
This alternative is protective of human health and the environment by treating
contaminants in the groundwater. By reducing VOC contamination in groundwater
CDM
Well 12A Final FFS April 2009
4-28
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
(and soil), it will reduce possible soil gas vapors at and near the Time Oil Building,
providing a secondary benefit to human health and the environment.
Compliance with ARARs
This alternative meets chemical-specific Federal and State ARARs through active
treatment of groundwater; however, compliance with chemical-specific ARARs
(reduction of CVOCs to MCLs) may not be achieved within the 30-year evaluation
period. It will be designed to reduce the mass in the area west of the Time Oil
Building by an estimated ninety percent. This mass reduction is necessary for
management of plume migration and is a critical step towards achieving compliance
with the chemical-specific ARARs at the proposed compliance well locations. Action-
and location-specific ARARs will apply and will be met by this alternative. Air
monitoring will need to be completed to ensure that air emissions are below
regulatory levels.
Long-Term Effectiveness and Permanence
The use of AS/SVE for groundwater will reduce the concentration of contaminants in
the plume by treating water inside the contaminated plume. Contamination that is
upgradient of this proposed AS/SVE treatment area must be destroyed so that it does
not provide a continuing source. During operation of the GETS, the area east of the
Time Oil Building is upgradient of the AS/SVE area.
Reduction of T/M/V Through Treatment
This alternative consists of the active removal and treatment of chlorinated organic
compounds from groundwater. The toxicity of the contaminants will be reduced
through removal from the groundwater and treatment at the surface by vapor
treatment. The process will reduce the mobility of contaminants as a result of the
hydrologic effects of the sparging process. The volume of contaminants in the aquifer
will be reduced by the AS/SVE due to the volatilization and removal of organics.
Short-Term Effectiveness
This alternative has the potential to have adverse short-term impacts on site workers
conducting the remediation activities since trenching will be performed in areas of
probable high contaminant concentrations. As a result, construction activities will
impose short-term worker health and safety risks. Controls will be put in place to
limit exposure to site workers and nearby residences.
Implementability
This alternative employs common technologies and practices that have been in use for
many years. Equipment is readily available and installation is relatively easy. The
operation of the treatment system will require more specialized training, since there
are air injection and vapor extraction mechanisms that will need to be monitored and
maintained, but it is not considered to be difficult. In some aquifer conditions, the
presence of high iron or manganese in the groundwater can cause excessive buildup
of scaling on the air sparging screens, or biofouling through bacterial activity. This
can require periodic treatment of the air injection wells by chlorination to reduce
bacterial growth.
CDM
Well 12A Final FFS April 2009
4-29
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
Implementation of this alternative will be more difficult due to it being implemented
in a city area. As a result, the remedial designers will need to consult with the city
engineer for the proper placement of the AS wells, the SVE wells, and the treatment
plant in order to take into account city utilities and existing roads. Time of
installation is relatively short, and expected to be completed in approximately six
months.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $3,344,800
¦ Annual O&M Cost: $545,100
¦ Present Worth: $5,275,500
4.4.4 Low Concentration Groundwater
This zone extends from the high concentration zone to the points of compliance wells:
Well 12A and proposed compliance wells 1 and 2.
4.4.4.1 Alternative LG1 - No Action
Overall Protection of Human Health and the Environment
The no action alternative is considered in accordance with NCP requirements and
provides a baseline for comparison with the other alternatives. No further action
would be conducted and the status of the site groundwater would remain unchanged.
This alternative does not include the implementation of any institutional controls such
as deed restrictions or future groundwater monitoring. CERCLA (Section 121(c)), as
amended by SARA (1986), would require that the site be reviewed every 5 years,
because contamination would remain on site.
The No Action Alternative fails to meet this threshold criterion of protectiveness and,
therefore, will not be evaluated further.
4.4.4.2 Alternative LG2 - Wellhead Treatment at Well 12A
Overall Protection of Human Health and the Environment
This alternative provides protection of human health and the environment by actively
pumping and treating the contaminated groundwater prior to discharge to the
Tacoma distribution system. Treating water to meet health criteria is the primary
goal; the decrease of contaminant concentrations in the aquifer due to the pumping
impacts is a secondary goal. Additionally, increased pumping of the well may
temporarily increase the concentration of COCs in the groundwater plume by
increasing the gradient from the source area towards Well 12A. This alternative
would also provide protection by eliminating human exposure pathways through
CDM
Well 12A Final FFS April 2009
4-30
-------
Section 4
Development and Detailed Evaluation of
Remedial Alternatives
prohibitions on groundwater well installation and groundwater use restrictions
within the plume area.
Compliance with ARARs
The purpose of the Well 12A treatment system is to meet chemical-specific Federal
and State ARARs for the public water supply.
Long-Term Effectiveness and Permanence
This alternative provides long-term effectiveness and permanence by treating
contaminated groundwater prior to discharge to the public water supply.
Groundwater extraction and treatment would also reduce contaminant concentrations
in the groundwater plume over time. However, it is recognized that the subsurface is
complex and more than one source exists in the area. Therefore, increased pumping
of the well may temporarily increase the concentration of COCs in the groundwater
plume by increasing the gradient from the source area towards Well 12A.
Effectiveness would be verified though a long-term groundwater monitoring
program and the potential for future exposure would be minimized through the
implementation of well installation and groundwater use restrictions within the
plume area.
Reduction of T/M/V Through Treatment
The stripping towers remove volatiles from the groundwater and they are emitted to
the atmosphere. When the well operates, some control is maintained for
contaminants that are in the vicinity of the well. However, data suggest that the
pumping action mobilizes contamination near the Time Oil property and
contaminants migrate further along the prevailing gradient. Therefore, operation of
the well is considered to not reduce T/M/V.
Short-Term Effectiveness
The system is already installed so there would be no short term effectiveness issues.
Implementability
This alternative is technically and administratively implementable. This alternative
has been constructed and operated since 1983. Minimal administrative tasks are
involved with the long-term groundwater monitoring program and minimal services
and materials are required. This alternative would require coordination with the
Tacoma-Pierce County Board of Health and Tacoma Water to implement ICs.
Cost
The capital cost, annual O&M costs, and present worth for this alternative are listed
below. Details of the cost estimates are presented in Appendix F.
¦ Capital Cost: $341,500
¦ Annual O&M Cost: $263,900
¦ Present Worth: $2,094,200
CDM
Well 12A Final FFS April 2009
4-31
-------
Section 5
Comparative Analysis of Alternatives
This section presents an overall comparison of the remedial alternatives which were
evaluated in Section 4. The alternatives are compared to each other for each treatment
zone based on the EPA evaluation criteria. A summary of the comparative analyses
for the alternatives is provided in Table 5-1.
5.1 Filter Cake and Shallow Impacted Soils
This treatment zone is located east of the Time Oil Building and extends from land
surface to a depth of ten feet. The alternatives for this treatment zone are
¦ Alternative FC1
¦ Alternative FC2
¦ Alternative FC3
¦ Alternative FC4
No Action
Institutional Controls
Capping
Excavation
5.1.1 Overall Protection of Human Health and the Environment
A threshold criterion set forth in the NCP is that the selected remedial action must be
protective of human health and the environment. This criterion assesses each
alternative's ability to provide adequate protection of human health and the
environment and describes how site risks associated with each exposure pathway are
eliminated, reduced, or controlled, through treatment, engineering, and/or
institutional controls.
Alternative FC1 would provide no protection against exposure to filter cake or
contaminated soil, nor would it provide protection of groundwater from migration of
contaminants in waste and soil. The potential for exposure to this material is high
since it is near the surface and data visualizations suggest the waste continues to serve
as a source of contamination to groundwater.
Alternatives FC2 and FC3 would provide moderate protection. The institutional
controls would prohibit the use of groundwater and limit excavation/ trenching,
which would limit exposure to contaminants. With the source material remaining in
place, contaminants will still be present to migrate to groundwater and travel away
from the controlled area. Capping would provide an additional level of protection,
since the direct contact pathway would be eliminated and the potential for
contaminants leaching further into the subsurface via infiltration or possibly traveling
away from the zone via runoff would be eliminated.
Alternative FC4 provides a high degree of protection of human health and the
environment through removal of contaminants from the site. Alternative FC4 would
be protective by removing the filter cake and shallow impacted soil from depths
down to an estimated ten ft bgs. The direct contact pathway would be removed and
CDM
Well 12A Final FFS April 2009
5-1
-------
Section 5
Comparative Analysis of Alternatives
the shallow contaminants would not be present to allow leaching to occur to depth or
runoff to carry contaminants off of the property.
5.1.2 Compliance with ARARs
This threshold criterion addresses whether a remedy would attain legally applicable
or relevant and appropriate requirements of Federal and State requirements,
standards, criteria, and limitations which are collectively referred to as "ARARs/' or
provides grounds for invoking a waiver under CERCLA section 121(d)(4).
Chemical specific ARARs for soil are the MTCA B-modified levels. Several CVOCs
have been shown to exceed these levels. The compounds are in filter cake and
shallow soil and the elevated concentrations have remained in the materials for more
than 20 years. These compounds would be expected to remain in the soil above
MTCA levels for the 30-year evaluation period. Therefore, Alternatives FC1, FC2 and
FC3 do not comply with ARARs. Alternative FC4 does comply with ARARs since it
removes the majority of filter cake and shallow soil with concentrations above the
MTCA B-modified level. Where contaminated soils remain in place, either further in
situ treatment would be performed or ICs would be used to reduce the potential for
exposure and comply with MTCA's 15-ft point of compliance for the direct contact
human exposure pathway. Offsite waste transportation and disposal of Alternative
FC4 would be performed in accordance with applicable RCRA, DOT, and Ecology
requirements; and only RCRA-permitted disposal facilities approved by EPA and
Ecology would be used. Additionally, Alternative FC4 (as does FC3) meets the RAO
of preventing the migration of contamination to depth.
5.1.3 Long-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to expected residual risk and the
ability of a remedy to maintain reliable protection of human health and the
environment over time. This criterion includes the consideration of residual risk that
will remain on site following remediation and the adequacy and reliability of controls.
Alternative FC1 would not provide long-term effectiveness or permanence.
Contaminants would persist and continue to migrate into the environment. No
controls would be implemented to prevent future exposure.
Alternatives FC2 and FC3 would provide a moderate level of long-term effectiveness
and permanence by minimizing future exposure through the use of institutional
controls and placing a barrier at the surface, respectively. Alternative FC3 would be
more effective given that the mobility of the contaminants present in the soil/ filter
cake would be reduced by eliminating infiltrating water and runoff. Both
alternatives would require long-term maintenance because contaminants would
remain on site; however, Alternative FC2 would require less O&M to maintain the
controls (e.g. signage for institutional controls versus resurfacing cap).
Alternative FC4 would provide the highest degree of long-term effectiveness and
permanence by removing the filter cake and contaminated soil and disposing of this
CDM
Well 12A Final FFS April 2009
5-2
-------
Section 5
Comparative Analysis of Alternatives
material off site. Little to no residual risk would remain in the areas where the filter
cake and contaminated soil was excavated. However, institutional controls and some
O&M measures would be required since some residual contamination may be left in
areas that cannot be excavated (e.g., near or underneath the Time Oil building).
5.1.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment
This criterion addresses the statutory preference for selecting remedial actions that
employ treatment technologies that permanently and significantly reduce the toxicity,
mobility, or volume of the hazardous substances. This criterion evaluates the
anticipated performance of the treatment technologies that may be included as part of
a remedy.
Alternative FC1 would not achieve any reduction in toxicity, mobility, or volume
through treatment, since no action would be taken for the filter cake and
contaminated soil.
Under Alternatives FC2 and FC3, treatment is not a component of the remedy.
Therefore, no reduction in toxicity or volume would be achieved through treatment.
However, contaminant mobility would be reduced through capping by removing the
impacts of precipitation (infiltration leaching contaminants to depth and runoff
carrying contaminants along the surface).
For Alternative FC4, the mobility and volume of the waste are also reduced at the site
because the material is excavated and transferred to the disposal location. The
toxicity is removed from the site, with the final toxicity contingent upon the disposal
methods. Disposal in a landfill will not reduce toxicity.
5.1.5 Short-Term Effectiveness
Short-term effectiveness addresses the period of time needed to implement the
remedy and any adverse impacts that may be posed to workers, the community, and
the environment during construction and operation of the remedy.
Under Alternatives FC1 no construction activities would be performed so no risks to
remediation workers or the community would occur. Little risk would also be
incurred for the implementation of institutional controls, Alternative FC2, since little
to no contact would be made with the contaminants.
For Alternative FC3 the risk would be low. Some contact may be made with the
contaminants while placing the cap. However, since no excavation is required, the
contact should be minimal. Remediation workers would not be subject to significant
risks associated with direct contact with contaminated materials. Air monitoring
would be required to reduce risks to workers and the community from potential
fugitive emissions during construction. Conventional engineering controls would be
used to prevent contaminated materials from migrating with run off water or
CDM
Well 12A Final FFS April 2009
5-3
-------
Section 5
Comparative Analysis of Alternatives
becoming airborne during construction. It is estimated that construction for
Alternative FC3 could be completed within one month of site mobilization.
Alternative FC4 would have moderately high risks to workers performing the
excavation due to volatilization of contaminants. The open excavation will also pose
a physical risk. Additionally, the volatiles may impact nearby residents and workers
at adjacent properties. Controls such as performing the work in cooler weather and
only maintaining a small portion of the excavation open at one time will limit
volatilization to the community. There would also be additional short term impacts
due to transport and offsite disposal of significant quantities of waste and
contaminated soil. Conventional traffic controls for waste transport, such as defining
specific travel routes to/ from the site for waste transportation vehicles and
coordinating waste shipments to avoid peak traffic hours, would be used to minimize
the potential for accidents. It is estimated that construction for Alternative FC4 can be
completed within two months of site mobilization.
5.1.6 Implementability
This criterion addresses the technical and administrative feasibility of implementing a
remedy from design through construction and operation. Factors such as the
availability of services and materials and coordination with other governmental
entities are considered.
Alternative FC1 would be the easiest to implement due to the lack of any active
construction or treatment activities. Alternative FC2 is only slightly more difficult to
implement since limited site activities are required. Some coordination will be
needed with regulators to implement administrative requirements.
Alternatives FC3 and FC4 are technically and administratively implementable. None
of these alternatives would require specialized equipment. Services required to place
asphalt caps and excavate waste and contaminated soil would be easily obtainable.
Access agreements and coordination with property owners will be required to
accommodate the construction activities for these two alternatives. Alternative FC4
would require imported clean fill to backfill the excavation, which is expected to be
readily available in the general vicinity of the site. The regulatory and permitting
requirements associated with offsite treatment/ disposal under Alternative FC4 are
not considered to be administratively intensive. Several RCRA Subtitle D Landfills
are located in the general vicinity of the site.
5.1.7 Cost
This criterion considers the construction, O&M, and present worth costs associated
with each alternative. The present worth has been calculated based on Federal policy
which recommends assuming a 7 percent discount rate over a 30-year evaluation
period.
Alternative FC1, the no action alternative, has no costs associated with it since no
remedial activities would be performed. Alternative FC2, institutional controls, has a
CDM
Well 12A Final FFS April 2009
5-4
-------
Section 5
Comparative Analysis of Alternatives
present worth of $114,800. Alternative FC3, capping, has a present worth of
$1,267,300 with the capital cost ($798,100) being a little more than half of the estimate.
Alternative FC4 is the most expensive with a present worth of $2,801,700 and a capital
cost of $2,346,500.
5.2 Deep Vadose Zone Soil and Upper Saturated Zone
East of the Time Oil Building
This treatment zone is located at depths from 10 ft to 55 ft bgs. The water table lies at
approximately 34 ft bgs. The alternatives for this treatment zone are
¦ Alternative SGI No Action
¦ Alternative SG2 Institutional Controls
¦ Alternative SG3 In Situ Thermal Remediation
5.2.1 Overall Protection of Human Health and the Environment
Alternative SGI, the no action alternative, provides no protection against possible
exposure to soil and contaminated groundwater, and will continue to be a source for
migration of contaminants via groundwater. Alternative SG2, institutional controls, is
protective of human health but does not address any environmental concerns since
there is no action taking place to mitigate the contaminants in the soil and
groundwater. Alternative SG3 provides a high degree of protection since it will be
designed to remove more than 90% of the contaminant mass in this source treatment
zone.
5.2.2 Compliance with ARARs
This threshold criterion addresses whether a remedy would attain legally applicable
or relevant and appropriate requirements of Federal and State requirements,
standards, criteria, and limitations which are collectively referred to as "ARARs," or
provides grounds for invoking a waiver under CERCLA section 121(d)(4).
Chemical specific ARARs for soil are the MTCA B-modified levels. Chemical specific
ARARs for the groundwater are MCLs. Concentrations of site COCs in soil and
groundwater in this treatment zone exceed these values. The values are significantly
elevated and more than one foot of LNAPL has been measured in a well in this zone.
These compounds would be expected to remain in the soil and groundwater above
MTCA levels and MCLs, respectively, for more than the 30-year evaluation period.
Therefore, Alternatives SGI and SG2 do not comply with ARARs.
The goal of Alternative SG3 is to eliminate/minimize the mass of contaminants in this
treatment zone to reduce the mass flux from deep soils into groundwater. The
remedy will be designed to remove more than 90% of the mass in the zone.
Therefore, the alternative complies with the RAO, but it may not achieve compliance
with chemical-specific ARARs within the treatment zone boundary. Compliance with
chemical-specific ARARs will be measured at the proposed compliance well locations.
The MTCA soil levels and groundwater MCLs may not be achieved within the 30-
CDM
Well 12A Final FFS April 2009
5-5
-------
Section 5
Comparative Analysis of Alternatives
year evaluation period; however, this remains a long-term goal. Residual impacts
exceeding MTCA cleanup levels and MCLs will be addressed via ICs and ongoing
wellhead treatment at Well 12A.
5.2.3 Long-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to expected residual risk and the
ability of a remedy to maintain reliable protection of human health and the
environment over time. This criterion includes the consideration of residual risk that
will remain on site following remediation and the adequacy and reliability of controls.
Alternative SGI would not provide long-term effectiveness or permanence.
Contaminants would persist at the site and continue to migrate into the environment.
No controls would be implemented to prevent future exposure. Alternative SG2
would provide minimal long-term effectiveness or permanence since controls would
be in place to limit contact; however, the contamination would remain at the site and
continue to be a source to the aquifer.
Alternative SG3 is effective in treating contaminants over the long-term. The
alternative will reduce contaminant concentrations in this source area. Thus, the
contribution of contamination to the groundwater will be reduced and concentrations
in the groundwater at downgradient locations will also decrease.
5.2.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment
This criterion addresses the statutory preference for selecting remedial actions that
employ treatment technologies that permanently and significantly reduce the toxicity,
mobility, or volume of the hazardous substances. This criterion evaluates the
anticipated performance of the treatment technologies that may be included as part of
a remedy.
Alternatives SGI and SG2 would not achieve any reduction in toxicity, mobility, or
volume through treatment, since no action would be taken for the contamination in
the soil and upper groundwater.
Reduction in volume would be achieved with Alternative SG3. The main goal of SG3
is to destroy contaminant mass, which, in effect, decreases hazardous substance
volume. Volatiles are transferred to GAC and ultimately destroyed by regeneration.
Alternative SG3 would also decrease toxicity by lowering soil and groundwater
concentrations and would reduce contaminant mobility due to reduced concentration
gradients.
5.2.5 Short-Term Effectiveness
Short-term effectiveness addresses the period of time needed to implement the
remedy and any adverse impacts that may be posed to workers, the community, and
the environment during construction and operation of the remedy.
CDM
Well 12A Final FFS April 2009
5-6
-------
Section 5
Comparative Analysis of Alternatives
Under Alternatives SGI no construction activities would be performed so no risks to
remediation workers or the community would occur. Low risks would also be
incurred during the implementation of institutional controls, Alternative SC2, since
little to no contact would be made with the contaminants.
For Alternative SG3 the risk would be moderate. Some contact may be made with the
contaminants while installing wells and piping. However, if the remedy is
constructed after the shallow soils are excavated (Alternative FC4), the risk would be
reduced. Remediation workers would not be subject to significant risks associated
with direct contact with contaminated materials. Air monitoring would be required
to reduce risks to workers and the community from fugitive emissions during
construction. Conventional engineering controls would be used to prevent
contaminated materials from migrating with run off water or becoming airborne
during construction. It is estimated that construction and completion of the heating
process would performed in 12 to 18 months after site mobilization.
5.2.6 Implementability
This criterion addresses the technical and administrative feasibility of implementing a
remedy from design through construction and operation. Factors such as the
availability of services and materials and coordination with other governmental
entities are considered.
Alternative SGI would be the easiest to implement due to the lack of any active
construction or treatment activities. Alternative SG2 is only slightly more difficult to
implement since limited site activities are required. Some coordination will be
needed with regulators to implement administrative requirements.
Alternative SG3 is technically and administratively implementable. This alternative is
innovative, but experienced contractors are available to implement the action.
Permits will need to be obtained for air emissions and the installation of wells, piping
and related remediation system equipment. Access agreements will be required to
accommodate the construction activities for this alternative. Coordination with
property owners would be required for the installation and operation of the
remediation system.
5.2.7 Cost
This criterion considers the construction, O&M, and present worth costs associated
with each alternative. The present worth has been calculated based on Federal policy
which recommends assuming a 7% discount rate over a 30-year evaluation period.
Alternative SGI, the no action alternative, has no costs associated with it since no
remedial activities would be performed. Alternative SG2, institutional controls, has a
present worth of $114,800. Alternative SG3, Insitu Thermal Remediation, has a
present worth of $4,662,000 and a capital cost of $4,106,200. The bulk of the capital
cost is for the in situ treatment remediation action.
CDM
Well 12A Final FFS April 2009
5-7
-------
Section 5
Comparative Analysis of Alternatives
5.3 High Concentration Groundwater
This treatment zone is the groundwater plume of TCE and cis-1,2-DCE at
concentrations greater than 300 ug/1. The alternatives for this treatment zone are
Alternative HG1
Alternative HG2
Alternative HG3
Alternative HG4
Alternative HG5
No Action
Institutional Controls
Groundwater Extraction and Treatment
Enhanced Anaerobic Biodegradation
Enhanced Anaerobic Biodegradation plus Air
Sparging/ Soil Vapor Extraction
5.3.1 Overall Protection of Human Health and the Environment
A threshold criterion set forth in the NCP is that the selected remedial action must be
protective of human health and the environment. This criterion addresses whether
each alternative provides adequate protection of human health and the environment,
and describes how site risks associated with each exposure pathway are eliminated,
reduced, or controlled, through treatment, engineering, and/or institutional controls.
Alternative HG1, the no action alternative, would provide no protection against
exposure to contaminated groundwater.
Alternative HG2 provides protection of human health and the environment through
the implementation of institutional controls to prevent installation of groundwater
wells and use of contaminated groundwater. However, without reduction or control
of the contaminated groundwater in this zone, it will continue to decrease the quality
of downgradient groundwater.
Alternative HG3, operation of the GETS, provides an additional degree of
protectiveness by actively removing contaminants from the aquifer and maintaining
some degree of hydraulic control. However, VOC concentrations in groundwater
remain elevated even though the GETS has operated for over 20 years. The
concentrations are estimated to remain elevated for more than the 30 year evaluation
period. Also, some data suggest that the GETS has a limited capture zone in the
southwest part of the high concentration plume.
Alternatives HG4 and HG5 provide a high degree of protection. Enhanced anaerobic
biodegradation and AS/SVE will reduce the contaminant concentrations in the high
concentration groundwater zone. The amendment used for the biodegradation will be
food grade so impact to drinking water wells and the environment are not a concern.
5.3.2 Compliance with ARARs
This threshold criterion addresses whether a remedy would attain legally applicable
or relevant and appropriate requirements of Federal and State requirements,
standards, criteria, and limitations which are collectively referred to as "ARARs," or
provide grounds for invoking a waiver under CERCLA section 121(d)(4). Any
CDM
Well 12A Final FFS April 2009
5-8
-------
Section 5
Comparative Analysis of Alternatives
remedial alternative selected by EPA must comply with all ARARs or, under certain
circumstances, waive one or more ARARs.
Alternatives HG1 and HG2 would not comply with chemical-specific ARARs. No
location-specific ARARs would apply to either alternative. Also, action-specific
ARARs would not apply because there would be no active remedial action associated
with these alternatives.
Alternative HC3, the groundwater extraction and treatment alternative, is not
expected to comply with chemical specific ARARs. The system has operated for 20
years and groundwater concentrations continue to exceed MCLs. The system
presently complies with surface water discharge limits and air emission standards.
Lastly, this alternative does not meet the RAO of reducing mass flux out of this zone
by 90%.
Alternatives HG4 and HG5 are not expected to comply with chemical specific ARARs
within the treatment zone boundary, as MCLs are not anticipated to be achieved
within the 30-year evaluation period. However, these alternatives would be designed
and operated to meet the RAO of reducing mass flux by 90%. This mass flux
reduction is necessary for management of plume migration and is a critical step
towards achieving compliance with the chemical-specific ARARs at the proposed
compliance well locations.
5.3.3 Long-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to expected residual risk and the
ability of a remedy to maintain reliable protection of human health and the
environment over time, once clean-up levels have been met. This criterion includes
the consideration of residual risk that will remain on site following remediation and
the adequacy and reliability of controls.
Alternatives HG1 and HG2 would not provide long-term effectiveness or
permanence. The potential for future exposure of contaminated groundwater to
receptors would not be eliminated given that no restrictions on well drilling or
groundwater use would be instituted for Alternative HG1. With Alternative HG2,
future exposure would be minimized through the implementation of well drilling and
groundwater use restrictions in the plume area. However, the high concentrations in
the groundwater would continue to impact downgradient locations.
Alternative HG3 would provide a moderate degree of long-term effectiveness and
permanence. Groundwater extraction and treatment would reduce contaminant
concentrations in the groundwater plume over time. However, based on the poor
response to pumping in the last 20 years, it is expected that contaminant reductions
will continue to be limited.
Alternatives HG4 and HG5 would provide the highest degree of long-term
effectiveness and permanence. These alternatives will be designed to aggressively
reduce VOC concentrations in the treatment zone and the EAB processes, once
CDM
Well 12A Final FFS April 2009
5-9
-------
Section 5
Comparative Analysis of Alternatives
stimulated, will remain effective over the long term through ongoing in situ
degradation of VOCs by natural bacteria. With alternative HC5, the application of
AS/SVE will likely limit the performance of the EAB in other sectors of the treatment
zone because the aerobic conditions that will be created by the AS/SVE system are
toxic to anaerobic bacteria.
5.3.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment
This criterion addresses the statutory preference for selecting remedial actions that
employ treatment technologies that permanently and significantly reduce the toxicity,
mobility, or volume of the hazardous substances. This criterion evaluates the
anticipated performance of the treatment technologies that may be included as part of
a remedy.
Alternatives HG1 and HG2 would not achieve any reduction in toxicity, mobility, or
volume through active treatment, since no action would be taken.
Alternative HG3 would reduce the toxicity and volume of contaminated groundwater
through carbon adsorption. Contaminants transferred from the groundwater to the
carbon media would be destroyed by the regeneration process.
Alternatives HG4 and HG5 would provide significant and permanent reduction in
toxicity, mobility and volume. The EAB technology will destroy contaminant mass,
which, in effect, decreases hazardous substance volume. EAB will significantly
reduce toxicity by degrading the ethenes into innocuous gasses and associated
reductions in concentration gradients will also decrease contaminant mobility. The
AS/SVE will transfer the contamination from groundwater to vapor, which will be
treated using carbon and destroyed by the regeneration process.
Alternative SG3 would also decrease toxicity by lowering soil and groundwater
concentrations and would reduce contaminant mobility due to reduced concentration
gradients.
5.3.5 Short-Term Effectiveness
Short-term effectiveness addresses the period of time needed to implement the
remedy and any adverse impacts that may be posed to workers, the community, and
the environment during construction and operation of the remedy.
Under Alternative HG1 no construction activities would be performed so no risks to
remediation workers or the community would occur. Low risks would be incurred
for the implementation of Alternative HG2, institutional controls, since little to no
contact would be made with the contaminants.
Alternative HG3, the extraction and treatment alternative, would have minimal
impact to remediation workers. The GETS is already constructed and the only
possible worker contact with contaminants would be during O&M of the system.
CDM
Well 12A Final FFS April 2009
5-10
-------
Section 5
Comparative Analysis of Alternatives
Alternatives HG4 and HG5 would have the greatest potential impact to remediation
workers and the community during construction of the systems. The installation of
both of the alternatives can be completed within six months of site mobilization.
Amendment injection is anticipated to occur in two rounds, so the same risks (vapors
at wells, onsite physical hazards and traffic) will be incurred twice.
5.3.6 Implementability
This criterion addresses the technical and administrative feasibility of implementing a
remedy from design through construction and operation. Factors such as the
availability of services and materials and coordination with other governmental
entities are considered.
Alternative HC1, the no action alternative would be the easiest to implement given
that no action is performed. Alternative HG2 is only slightly more difficult to
implement since limited site activities are required. Some coordination will be
needed with regulators to implement administrative requirements. Alternative HG3
is equivalent to HG2 in implementability, since the GETS is already constructed and
only standard O&M activities are required.
Alternatives HG3 and HG4 would be the most difficult to implement. These
technologies are relatively standard and several contractors are available that have
experience with their installations. However, since the wells (and piping for the
AS/SVE) for the alternatives will be installed on private properties, near buildings
and along road and railroad right of ways, administrative requirements and traffic
control requirements will be involved.
Treatment of VOCs in groundwater with EAB is a proven technology. However, to
facilitate the proper application of the technology, the installation may need to
proceed in phases. During the first phase only one line of wells would be used for
amendment addition. The results of the first phase would be used to help guide
subsequent phases. The regulatory and permitting requirements associated with
installing the amendment injection wells and constructing the treatment system for
vapor may be administratively intensive.
5.3.7 Cost
This criterion considers the construction, O&M, and present worth costs associated
with each alternative. The present worth has been calculated based on Federal policy
which recommends assuming a 7percent discount rate over a 30-year evaluation
period. Where applicable, a shorter period was used. Alternative HG1, the no action
alternative, has no costs associated with it since no remedial activities would be
performed. Alternative HG2, institutional controls, has a present worth of $173,500.
Alternative HG3, GETS, has a present worth of $3,708,000 which is due to the high
O&M costs for the 30-year period. Alternative HG4, EAB, has a present worth of
$4,217,700 and a capital cost of $2,423,900. Alternative HG5, EAB plus AS/SVE, has a
present worth of $5,275,500 and a capital cost of $3,344,800.
CDM
Well 12A Final FFS April 2009
5-11
-------
Section 5
Comparative Analysis of Alternatives
5.4 Low Concentration Groundwater
This treatment zone is the shallow and lower aquifer extending from the high
concentration groundwater treatment zone to the points of compliance wells: Well
12A and proposed compliance wells 1 and 2. The alternatives for this treatment zone
are
¦ Alternative LG1 No Action
¦ Alternative LG2 Wellhead Treatment at Well 12A
5.4.1 Overall Protection of Human Health and the Environment
A threshold criterion set forth in the NCP is that the selected remedial action must be
protective of human health and the environment. This criterion addresses whether
each alternative provides adequate protection of human health and the environment,
and describes how site risks associated with each exposure pathway are eliminated,
reduced, or controlled, through treatment, engineering, and/or institutional controls.
Alternative LG1, the no action alternative, would provide no protection against
exposure to contaminated groundwater.
Alternative LG2, the extraction and treatment alternative, provides protectiveness by
actively removing contaminants from the groundwater aquifer at Well 12A by
treating it with air stripping towers prior to discharge to the distribution system.
Alternative LG2 also provides protection of human health and the environment
through the implementation of institutional controls to prevent installation of
groundwater wells and restrict use of contaminated groundwater. Routine
groundwater sampling would provide information about the migration and
attenuation of the groundwater plume during and after implementation of source
area actions. Strong evidence has been collected that indicates aerobic cometabolic
degradation is occurring in this treatment zone.
5.4.2 Compliance with ARARs
This threshold criterion addresses whether a remedy would attain legally applicable
or relevant and appropriate requirements of Federal and State requirements,
standards, criteria, and limitations which are collectively referred to as "ARARs," or
provide grounds for invoking a waiver under CERCLA section 121(d)(4). Any
remedial alternative selected by EPA must comply with all ARARs or, under certain
circumstances, waive one or more ARARs.
Alternative LG1, the no action alternative, would not comply with chemical-specific
ARARs. No location-specific ARARs would apply to this alternative. Also, action-
specific ARARs would not apply because no remedial action would be conducted.
Alternative LG2, the groundwater extraction and treatment alternative, is expected to
comply with all chemical, location, and action-specific ARARs. These ARARs include
water treatment standards and air emission standards.
CDM
Well 12A Final FFS April 2009
5-12
-------
Section 5
Comparative Analysis of Alternatives
5.4.3 Long-Term Effectiveness and Permanence
Long-term effectiveness and permanence refers to expected residual risk and the
ability of a remedy to maintain reliable protection of human health and the
environment over time. This criterion includes the consideration of residual risk that
will remain on site following remediation and the adequacy and reliability of controls.
Alternative LCI, the no action alternative, would not provide long-term effectiveness
or permanence. The potential for future exposure of contaminated groundwater to
receptors would not be eliminated given that no restrictions on well drilling or
groundwater use will be implemented other than what currently exists in Tacoma-
Pierce County Board of Health Resolution No. 2002-3411, Land Use Regulations and
the Washington Administrative Code.
Alternative LC2, the extraction and treatment alternative, would provide the highest
degree of long-term effectiveness and permanence. Groundwater extraction and
treatment provides a water supply to the public that meets water quality standards. In
the aquifer, the operation of Welll2A has been shown to mobilize contaminants and
increase the rate of contaminant migration towards the well. Effective
implementation of this alternative will require coordination with Tacoma Water to
implement institutional controls that may include temporary operational guidelines
and/or restrictions on Tacoma Water's use of the South Tacoma well field.
5.4.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment
This criterion addresses the statutory preference for selecting remedial actions that
employ treatment technologies that permanently and significantly reduce the toxicity,
mobility, or volume of the hazardous substances. This criterion evaluates the
anticipated performance of the treatment technologies that may be included as part of
a remedy.
Alternative LG1 provides no reduction in toxicity, mobility, or volume through active
treatment, since no action would be taken. Alternative LG2, the extraction and
treatment alternative, would reduce the toxicity and volume of contamination in the
extracted groundwater through air stripping towers. The operation of Well 12A
increases the mobility of contaminants in the aquifer since it creates a steeper
hydraulic gradient and draws contaminants from areas of higher concentration.
5.4.5 Short-Term Effectiveness
Short-term effectiveness addresses the period of time needed to implement the
remedy and any adverse impacts that may be posed to workers, the community, and
the environment during construction and operation of the remedy.
No construction activities would be performed under either alternative so no
additional risks to construction workers or the community would occur during
CDM
Well 12A Final FFS April 2009
5-13
-------
Section 5
Comparative Analysis of Alternatives
implementation. There would be minimal exposure risk to personnel during
activities associated with the long-term groundwater monitoring sampling program
of Alternative LG2 and while performing O&M at Well 12A.
5.4.6 Implementability
This criterion addresses the technical and administrative feasibility of implementing a
remedy from design through construction and operation. Factors such as the
availability of services and materials and coordination with other governmental
entities are considered.
Alternative LG1 would be the easiest to implement given that no action would be
performed.
Alternative LG2 has minor implementability issues associated with the long-term
groundwater monitoring program and O&M. There would be some coordination
required with Tacoma Water and the Tacoma Board of Health to secure zoning
changes preventing well drilling, and institution of deed restrictions to prevent or
restrict groundwater use in the plume area.
5.4.7 Cost
This criterion considers the construction, O&M, and present worth costs associated
with each alternative. The present worth has been calculated based on Federal policy
which recommends assuming a 7 percent discount rate over a 30-year evaluation
period.
Alternative LG1, the no action alternative, has no costs associated with it since no
remedial activities would be performed. Alternative LG2, Well 12A Treatment, has a
present worth of $2,094,200 which is primarily due to the O&M costs applied over the
30-year period. These O&M costs are based on costs incurred in the last three years.
If conditions change, then this estimate would change. If pumping increases, the costs
would increase and if pumping decreases, the costs would decrease.
5.5 Alternative Groups
Table 5-2 presents the potential groups of alternatives of the various remedial
alternatives that can be assembled to develop a plume management strategy and
address overall site contamination across the impacted media. While several groups
can address contamination, the combination of aggressive mass removal in the source
zones (excavation, ITR, and EAB), short-term hydraulic containment with the GETS,
and wellhead treatment at Well 12Ain the low concentration zone provides a robust
strategy that meets RAOs. Alternative Groups 1 and 2 are No Action and
Institutional Controls (under current remediation conditions), respectively.
Alternative Groups 3 and 4 provide an aggressive strategy. Both of these groups meet
RAOs, but Group 4 is more expensive since capping and AS/SVE are included with
the group. A conceptual schedule of remedial activities for Group 3 is presented in
Figure 5-1. As shown in the schedule, excavation (and backfill) will be performed,
and then ERH will be initiated prior to completing the backfilling. Conceptually,
CDM
Well 12A Final FFS April 2009
5-14
-------
Section 5
Comparative Analysis of Alternatives
ERH piping will be placed below grade then the excavation will be brought to grade
to bury the piping. The first injection of the EAB amendment will occur at
approximately the end of the ERH activity. As shown on the schedule, several rounds
of performance groundwater sampling and flux measurements will be performed.
5.6 Long Term Decision Guidelines
An overarching plume management strategy that links the target treatment zones and
source treatment performance goals with remedial alternatives is proposed. Also, in
support of EPA's ongoing movement of green cleanup methods, the strategy will
incorporate sustainable practices where applicable. Performance criteria and decision
rules will be established for the strategy and alternatives selected as the proposed
remedy. The criteria and rules that will be developed will be based on site data and
case histories. Site data to refine the criteria and rules will be collected in a pre-design
investigation. The items below provide initial guidelines that will be used to specify
criteria and rules.
¦ The ability to modify the overall treatment area or volume in real time during
installation of the remediation system (e.g., ITR) will need to be established if
the target is not as originally identified. A good communication network
between the engineer/scientists, the property owner(s), contractor(s), and
regulatory agencies facilitates the modifications.
¦ An adequate data collection program needs to be established so that the
facilities (e.g., soil vapor extraction wells) are installed at adequate locations.
For example, when installing vapor extraction wells, soil and/ or groundwater
screening data should be collected. If contaminants are detected above a
specified concentration, additional wells can be installed. Conversely, if
contaminants are not detected (or are detected at negligible concentrations),
proposed wells may be removed.
¦ Multiple parameters need to be monitored and considered in assessing
performance, as a single monitoring parameter that is sufficient for evaluating
performance is not available. For example, based on experience with ITR at
other sites, the most important parameters for assessing performance and
determining when to terminate treatment are temperature (three-dimensional
distribution and average), groundwater concentrations at internal monitoring
locations, and mass of water, vapor and contaminant extracted. Additionally,
monitoring of chloride over time would be useful as a potential indicator of in
situ dechlorination reactions. Because heating will likely not be uniform,
temperature monitoring points should be distributed at least one sensor per
100 cubic yards of treated soil, including one sensor for every five feet in the
vertical direction.
¦ Groundwater monitoring data will be evaluated to characterize the decreasing
mass, concentrations, and flux. Statistical analyses will be performed on the
CDM 515
Well 12A Final FFS April 2009
-------
Section 5
Comparative Analysis of Alternatives
data following methods that are outline in publications such as Statistical
Methods for Groundwater Monitoring (Gibbons 1994).
¦ Performance goals and monitoring/ decision approach should be defined with
as much detail as possible so that if actual site conditions are significantly
different than anticipated, the project can make adequate adjustments. For
example, if the subsurface heats up unevenly, the project team shall be able to
change the performance model in real time to be aligned with the overarching
performance goal of maximizing mass reduction rather than only staying
focused on meeting temperature monitoring goals specified in the contract.
¦ Real time or close to real time data for some parameters such as temperature
and concentration are useful to help the stakeholders make accurate and
timely decisions and support a flexible operating strategy.
¦ Temporal groundwater contaminant concentration data is a key measure of
performance. Based on case history, little rebound is observed after ITR
treatment. However, even at sites with rebound and potential issues with
diffusion from low permeability zones, groundwater concentration data from
monitoring wells is a good baseline for interpretation of treatment
effectiveness. Other measures, such as contaminant flux, will be added to
refine the interpretation of performance.
¦ Temperature monitoring outside the targeted ITR treatment zone is a good
measure of the adequacy of hydraulic control.
An agreement will be prepared between EPA, Washington Department of Ecology
and the City of Tacoma on the execution of the remedial action and long-term
monitoring. A possible scenario is that EPA will monitor flux, groundwater
concentrations, and mass reduction in addition to completing/ constructing the
remedial action and Ecology and Tacoma will operate the GETS. EPA will use the
flux, groundwater and mass data to determine when the GETS can be turned off and
will notify Ecology and Tacoma. The data and evaluation used to make the
determination will be provided to Ecology and Tacoma. The action will be
considered an interim action until the cleanup level is attained at conditional points of
compliance well CH2M-2, proposed well IM-1 and proposed wells IM-2. The State
would be taking over the site after the GETS is turned off and:
¦ 90% flux reduction groundwater remediation level is met
¦ MCLs are met at the compliance wells 12A, new well CW1, and new well CW2
The transfer to the State would be before groundwater cleanup levels are attained at
the conditional points of compliance well CH2M-2, new well IM-1 and new well IM-
2. This description is a summary of possible future requirements; a more formal and
definitive agreement will be discussed and prepared between the stakeholders.
CDM
Well 12A Final FFS April 2009
5-16
-------
Section 6
References
Brown and Caldwell; Sweet, Edwards & Associates; Robinson & Noble, Inc. 1985.
Clover/Chambers Creek Geohydrologic Study for Tacoma-Pierce County Health Department.
Final Report. Report prepared for the Tacoma-Pierce County Health Department.
Tacoma, Washington. July.
CDM. 2008. Focused Feasibility Study Draft Remedial Alternatives Screening
Memorandum, Well 12A Superjund Site, Tacoma Washington. Report prepared for the
USEPA Region 10. August 5.
Environmental Quality Management, Inc. 2004. User's Guide For Evaluating Subsurface
Vapor Intrusion Into Buildings. Report prepared for the Industrial Economics
Incorporated. February.
Gibbons, R.D. 1994. Statistical Methods for Groundwater Monitoring. Published by
Wiley-IEEE. 286 pages.
ICF Kaiser Engineers, Inc. 1999. Groundwater Summary Report, South Tacoma
Channel/Well 12A Superjund Site, Tacoma, Washington. December.
ICF Kaiser Engineers, Inc. 1999. LNAPL and Soil Investigation Report, South Tacoma
Channel/Well 12A Superjund Site, Tacoma, Washington. September.
RS Means. 2008. Means Costworks Cost Data 2008 - Version 11.0.
Starr, R.C., M. C. Koelsch, L. N. Peterson and K.S. Sorenson. Assessing Aerobic Natural
Attenuation of Trichloroethene Using the Tracer-Corrected Method. Proceedings of the 8th
International In Situ and On-Site Bioremediation Symposium, Battelle Press, Columbus, OH,
June 2005.
URS. 2005. Draft Field Investigation and Capture Zone Analysis Report, Commencement
Bay, South Tacoma Channel/Well 12A Superjund Site, Tacoma, Washington. September.
U.S. Army Corps of Engineers, Seattle District, EPA Kerr Environmental Research
Laboratory, Pacific Northwest National Laboratory, and the University of Florida.
2008. Final East Gate Disposal Yard Thermal Remediation Performance Assessment After
Action Report. Fort Lewis Logistics Center, Fort Lewis, Washington. September.
USEPA. 2000. A Guide to Developing and Documenting Cost Estimates During the
Feasibility Study. EPA 540-R-00-002. OSWER 9355.0-75. July.
CDM
Well 12A Final FFS April 2009
6-1
-------
Section 6
References
USEPA. 1998. Guidance for Conducting Remedial Investigations and Feasibility Studies
Under CERCLA.
USEPA. 1996. Presumptive Response Strategy and Ex-Situ Treatment Technologies for
Contaminated Ground Water at CERCLA Sites. October.
USEPA. 1985. Record of Decision. South Tacoma Channel - Well 12A, Tacoma,
Washington. May.
USEPA. 1983. Superfund Record of Decision. Commencement Bay, South Tacoma
Channel OU-1 (EPA/ROD/RlO-83/OOl). March.
Washington Department of Ecology. 2007. Model Toxics Control Act Statute and
Regulation. Toxics Cleanup Program. Publication No. 94-06 Revised. November.
Washington Department of Ecology. 2006. Workbook for Calculating Cleanup Levels for
Individual Hazardous Substances (MTCASGLll.xls).
http://www.ecy.wa.gov/programs/tcp/tools/toolmain.html
CDM
Well 12A Final FFS April 2009
6-2
-------
Tables
-------
Table 2-1
Model Toxics Control Act Soil Cleanup Level Comparison
Compound
Method A (mg/kg)
Method B (mg/kg)
Method B
modified (mg/kg)
TCE
0.03
77
23
PCE
0.05
1.9
1.7
1,1,2,2-PCA
0.59*
5.0
4.6
cis-1,2-DCE
78*
800
800
trans-1,2-DCE
11*
1600
1600
VC (adulthood)
0.06*
1.4
1.4
VC (lifetime)
0.06*
0.71
0.71
* Values from Oak Ridge Natonal Laboraory (ORNL) Adjusted Residential
(June 2008) since Method A values not available. One VC value
presented in ORNL, and value posted here for both adulthood and lifetime.
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
TABLE 2-2
CALCULATION OF SOIL CLEANUP LEVELS (INGESTION EXPOSURE ROUTE) - Method B
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Non-cancer Hazard
Chemical of Concern
ABS
Cancer Risk
Noncancer Hazard
Equation 740-1 Definition:
CsoN = (RfD x ABWx UCF x HQ x AT) / (SIR x AB1 x EF x ED)
CPF
(mg/kg-day)"1
^soil
(mg/kg)
RfD
(mg/kg-day)
^soil
(mg/kg)
Parameter
Definition
Value
1,1,2,2-Tetrachloroethane
0.03
0.2
5.0
NE
NE
Csoil
Soil cleanup level (mg/kg)
c/s-1,2,-Dichloroethene
0.0005
NE
NE
0.01
800
RfD
ABW
UCF
SIR
AB1
EF
HQ
AT
ED
Reference Dose (mg/kg-d)
Average body weight over the exposure duration (kg)
Unit conversion factor (mg/kg)
Soil ingestion rate (mg/day)
Gastrointestinal absobtion fraction (unitless)
Exposure frequency (unitless)
Hazard quotient (unitless)
Averaging time (yrs)
Exposure duration (yrs)
chemical-specific
16
1000000
200
1
1
1
6
6
Tetrachloroethene
0.03
0.54
1.9
NE
NE
trans-1,2-Dichloroethene
0.0005
NE
NE
0.02
1600
Trichloroethene
0.03
0.013
77
NE
NE
Vinyl Chloride (adulthood)
0.0005
0.72
1.4
NE
NE
Vinyl Chloride (lifetime)
0.0005
1.4
0.71
NE
NE
Cancer Risk
Equation 740-2 Definition:
CsoN = (RISKx ABWx AT x UCF) / (CPF x SIR x AB1 x ED x EF)
Csoil
Soil cleanup level (mg/kg)
RISK
ABW
AT
UCF
CPF
SIR
AB1
ED
EF
Acceptable cancer risk level (unitless)
Average body weight over exposure duration (kg)
Averaging time (yrs)
Unit conversion factor (mg/kg)
Carcinogenic potency factor (kg-day/mg)
Soil ingestion rate (mg/day)
Gastrointestinal absobtion fraction (unitless)
Exposure duration (yrs)
Exposure frequency (unitless)
0.000001
16
75
1000000
chemical-specific
200
1
6
1
Toxicity value sources: NE = Not Evaluated
1) Integrated Risk Information System (IRIS 2008)
2) Cal/EPA
3) RICEA - Provisional value
CDM
Well 12A Final FFS April 2009 Page 1 of 1
-------
TABLE 2-3
CALCULATION OF SOIL CLEANUP LEVELS (INGESTION AND DERMAL EXPOSURE ROUTES) - Modified B
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Non-cancer Hazard
ABS
Cancer Risk
Noncancer Hazard
Equation 740-4 Definition:
Chemical of Concern
CPFo
CPFd
^soil
RfDo
RfDd
^soil
Csol| = (HQ x ABWx AT) / (EF x ED) x {[(1/RfDo x (SIR x AB1)/(106 mg/kg)] +
* ARSl/rm6 mn/knm
[(1/RfDd x (SA x AF
(mg/kg-day)"1
(mg/kg-day)"1
(mg/kg)
(mg/kg-day)
(mg/kg-day)
(mg/kg)
Parameter
Definition
Value
1,1,2,2-T etrachloroethane
0.03
0.2
0.25
4.6
NE
NE
NE
Csoil
Soil cleanup level (mg/kg)
cis-1,2,-Dichloroethene
0.0005
NE
NE
NE
0.01
0.008
800
HQ
Hazard quotient (unitless)
1
fetrachloroethene
0.03
0.54
0.68
1.7
NE
NE
NE
ABW
Average body weight over the exposure duration (kg)
16
trans -1,2-Dichloroethene
0.0005
NE
NE
NE
0.02
0.016
1600
AT
Averaging time (yrs)
6
Trichloroethene
0.03
0.04
0.05
23
NE
NE
NE
EF
Exposure frequency (unitless)
1
Vinyl Chloride (adulthood)
0.0005
0.72
0.90
1.4
NE
NE
NE
ED
Exposure duration (yrs)
6
Vinyl Chloride (lifetime)
0.0005
1.4
1.8
0.71
NE
NE
NE
SIR
Soil ingestion rate (mg/day)
200
AB1
Gastrointestinal absobtion fraction (unitless)
1
SA
Dermal surface area (cm2)
2200
AF
Adherance factor (mg/cm2-d)
0.2
ABS
Dermal absortion fraction (unitless)
chemical-specific
RfDo
Oral reference dose (mg/kg-d)
chemical-specific
RfDd
Dermal reference dose (mg/kg-d) (RfDo x Gl)
chemical-specific
Gl
Gastrointestinal absorbtion conversion factor (unitless)
0.8
Cancer Risk
Equation 740-5 Definition:
CS0I,= (RISKx ABWx AT) / (EF x ED) x [(SIR x AB1 xCPFo)/(106 mg/kg) + [(SA x AF x ABS x
CPFd) / (106 mg/kg)]
Csoil
Soil cleanup level (mg/kg)
RISK
Acceptable cancer risk (unitless)
0.000001
ABW
Average body weight over the exposure duration (kg)
16
AT
Averaging time (yrs)
75
EF
Exposure frequency (unitless)
1
ED
Exposure duration (yrs)
6
SIR
Soil ingestion rate (mg/day)
200
AB1
Gastrointestinal absorbtion fraction (unitless)
1
CPFo
Oral cancer potentecy factor (mg/kg-d)
chemical-specific
CPFd
Dermal cancer potency factor (mg/kg-d) (CPFo / Gl)
chemical-specific
Gl
Gastrointestinal absorbtion conversion factor (unitless)
0.8
SA
Dermal surface area (cm2)
2200
AF
Adherance factor (mg/cm2-d)
0.2
ABS
Dermal absortion fraction (unitless)
chemical-specific
Toxicity value sources: NE = Not Evaluated
1) Integrated Risk Information System (IRIS 2008)
2) Cal/EPA
3) RICEA - Provisional value
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Table 2-4
Soil to Groudwater Pathway Cleanup Levels - Method B
Chemical Specific:
CAS #:
Chemical:
Oral Reference Dose
Oral Cancer
Inhalation Reference
Inhalation Cancer
Inhalation
Koc (Soil Organic
Henrys Law
Aqueous
Dilution Factor
Groundwater
Cleanup Level
(RfDo) (mg/kg-day)
Potency Factor
Dose (RfDi) (mg/kg-
Potency Factor (CPFi)
Correction
Carbon-Water
Constant (unitless) Solubility
(DF) (unitless)
Criterion
(CUL) (mg/kg)
(CPFo) (kg-day/mg) day)
(kg-day/mg)
Factor (INH)
Partitioning
(Hcc) (unitless)
(S) (mg/L)
(ug/L)
(unitless)
Coefficient) (L/kg)
156-59-2
dichloroethylene;1,2-,cis
1.00E-02
Researched-No Data
1.00E-02
Researched-No Data
2.00E+00
3.60E+01
1.70E-01
3.50E+03
2.00E+01
7.00E+01 1
1.57E-01
156-59-2
dichloroethylene;1,2-,cis
1.00E-02
Researched-No Data
1.00E-02
Researched-No Data
2.00E+00
3.60E+01
1.70E-01
3.50E+03
1.00E+00
7.00E+01 1
7.90E-03
156-60-5
dichloroethylene; 1,2-,trans
2.00E-02
Researched-No Data
2.00E-02
Researched-No Data
2.00E+00
3.80E+01
3.90E-01
6.30E+03
2.00E+01
1.00E+03 1
2.89E+00
156-60-5
dichloroethylene;1,2-,trans
2.00E-02
Researched-No Data
2.00E-02
Researched-No Data
2.00E+00
3.80E+01
3.90E-01
6.30E+03
1.00E+00
1.00E+03 1
1.44E-01
79-34-5
tetrachloroethane; 1,1,2,2-
Researched-No Data
2.00E-01
Researched-No Data
2.00E-01
2e+00
7.90E+01
1.40E-02
3.00E+03
2.00E+01
6.70E-02 2
2.00E-04
79-34-5
tetrachloroethane; 1,1,2,2-
Researched-No Data
2.00E-01
Researched-No Data
2.00E-01
2e+00
7.90E+01
1.40E-02
3.00E+03
1.00E+00
6.70E-02 2
1.10E-05
127-18-4
tetrachloroethylene
1.00E-02
5.40E-01
Researched-No Data
2.10E-02
2e+00
2.70E+02
7.50E-01
2.00E+02
2.00E+01
5.00E+00 1
5.86E-02
127-18-4
tetrachloroethylene
1.00E-02
5.40E-01
Researched-No Data
2.10E-02
2e+00
2.70E+02
7.50E-01
2.00E+02
1.00E+00
5.00E+00 1
2.90E-03
79-01-6
trichloroethylene
3.00E-04
8.90E-02
1.00E-02
8.90E-02
2e+00
9.40E+01
4.20E-01
1.10E+03
2.00E+01
5.00E+00 1
2.43E-02
79-01-6
trichloroethylene
3.00E-04
8.90E-02
1.00E-02
8.90E-02
2e+00
9.40E+01
4.20E-01
1.10E+03
1.00E+00
5.00E+00 1
1.20E-03
79-01-6
trichloroethylene
3.00E-04
8.90E-02
1.00E-02
8.90E-02
2e+00
9.40E+01
4.20E-01
1.10E+03
2.00E+01
2.40E+00 3
1.17E-02
79-01-6
trichloroethylene
3.00E-04
8.90E-02
1.00E-02
8.90E-02
2e+00
9.40E+01
4.20E-01
1.10E+03
1.00E+00
2.40E+00 3
6.00E-04
Site Specific Data:
Total Soil
Porosity (n)
(unitless)
Volumetric
Water Content
(0w) (L/kg)
Dry Soil Bulk
Density (pb) (kg/I)
Fraction Soil Organic
Carbon (foe) (unitless)
3.00E-01
5.40E-02
1.88
1.70E-03
Notes:
The Chemical Specific information was extracted from the Cleanup Levels and Risk Calculation (CLARC) database.
"Researched-No Data" means research has been conducted and no data exists in the CLARC database for this parameter.
CUL calculated using the Workbook for Calculating Cleanup Levels for Individual Hazardous Substance.
The Site Specific information is referenced in URS, 2005, excpet the Volumetric Water Content which is referenced in EQM, 2004.
The default DF value is 20 in the unsaturated zone and 1 in the saturated zone.
1. MCL - Maximum Contaminant Level
2. ORNL -Oak Ridge National Laboratory
3. Ecology Method B Level for groundwater
CDM
Well 12A Final FFS April 2009
Page 1 of 2
-------
Table 2-5
Groundwater Data from February/March 2008
Analyte
MCL
(uq/L)
CBW-1
CBW-4
CBW-5
CBW-6
CBW-7-1
CBW-7-2
(DUP)
CBW-9
CBW-10-1
CBW-10-2
(DUP)
CBW-11
CH2M-1
CH2M-2
CH2M-3
CH2M-4
EW-1
EW-2
EW-3
EW-4
EW-5
ICF-2-1
ICF-2-2
(DUP)
ICF-3-1
ICF-3-2
(DUP)
ICF-4
ICF-5D
ICF-5S
KRRF-1
MW-301
MW-302
MW-304
MW-305
MW-306
MW-307
MW-308
MW-89_7
MW-A
1,4-Dioxane (SVOC)
6.1*
1U
1U
1U
1U
0.5J
1U
1U
1U
1U
1U
0.67J
1.3
1U
1U
0.6J
1U
1.2
3.5
8.7
4.7
6.1
1UJ
1U
1.1U
1U
1U
1U
42
360J
13
300J
4.4
10
6.8
1U
7.2
1,1,1,2-Tetrachloroethane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,1.1-Trichloroethane
1U
1U
l id
lid
lid
1U
lid
1U
IU
1U
IU
1U
IU
1U
IU
1U
IU
1U
IU
1U
lid
IU
iy
50U ....
iy
IU
iy
IU
iy
IU
iy
IU
iy
IU
1U
1.1,2-T richloroethane
v--yiU"-y-
"''y-iy yy
'W-1LT>.::
':":":"Mld,
:;I' 1 ;U ; ;'*
':":":"MU,
':":":"MU,
"-y-iuyy
':":":"MU,
':":":";4jy
"'./•>
9.3
':":-y,iU"..<'
:;I' 1,U y :'*
':"y,lU"..-':'
50U
16
4.5
'""yviuy
':":-yiy y.;:
1.1
':''y-iyyy
'""yviuy
':":-yiy y.;:
'""yviuy
iy :'*
jy,,:.
1.1-Dichloroethane
1U y-.
1U.- y
-tu'
yyt.5yy
yy^y^r.v
•¦y ®vy
••X: ?tu
yy^y^r.v
••y.iw"-.v
yytyyv
••X: ?tu
yy^y^r.v
:'y..".iu:' y.
yy-lii,--'
"'ylS
1U
- y?W\-y
50U
:'y.:iuy.y
. y-iii'. -V
1U
>--;y:au'
yy^# y
y;;:fly:yy
1U
>--;y:au'
1U
y;;:fly:yy
-,1U.-
1U
-.-.y iu
1U
A'lwyy
y\>4y-
.\v"iyy..>
¦.'•v Mw
-.y-iyry.;
yyl,U:;;'
.\v"iyy..>
1.3
1.6
"x y4Ms
•^"-aEs:- y;
170 J
iu yy
1U
v-,^soy;-yy
>• yliy -. •
1U
yyiy.;:
'
y- :..#.y
y.yiyy,
•y-~ 1U ;"
v
yy-iy.y -
1.1-Dichloropropanone
- 2UJ
'•••' 2UJ
A 2UJ
2UJ
.' 2UJ -
2UJ a ~
y
2UJ -
?:2UJ A7
yyaUA
2UJ -
2UJ
2UJ
2UJ 'y
' 2UJ '
y;y2u,yy
'..yaya-'-y.
' - 2UJ
ioou
;yy-2y-- y
a 2UJ
2UJ
y. 2U
2U y
-2S*vV
:>M,-y
;y 2UJ
\y -aj
1,1-Dichloropropene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,3-Trichlorobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,3-Trichloropropane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,4-Trichlorobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
0.61 J
1U
1U
1U
1U
49J
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2U
2U
1U
1U
1U
1U
1U
1U
2UJ
2UJ
2U
2U
2U
2U
1U
1,2-Dichloroethane
1U
1U
l id
lid
lid
iy
iy
iy
IU
iy
iy
iy
1,2-Dichloropropane
v--yiU"-y-
—;.<|y .;:?
':":":yiuy
":":"y:W •'
'""yviuy
w;;-iy
'""yviuy
'""yviuy
'""yviuy
I ,>uicnioropropane
1U y-.
1U .-
-tw
1U
1U
1U
1U
1U
>--;y:ay
1U
1U
1U
1-Chlorobutane
1U
1U
1U
1U
5.3
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2,2-Dichloropropane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2-Butanone
1U
1U
1U
1U
1U
3.1 J
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1.1
1U
1U
1U
1U
1U
25J
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2-Chlorotoluene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
3.3
2.7
1U
1U
1U
1U
50U
1.1
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2-Hexanone
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1UJ
1U
1U
1U
1U
1U
1U
2-Pentanone. 4-methyl-
1U
1U
l id
lid
lid
1U
lid
lid
IU
IU
1U
IU
iy
IU
iy
IU
iy
IU
2-Propanone
*;y,2U''-y-
W;>2U
W:
':":":;>2U"-';y
':":":"Mld,
W;>2U
':":":;>2Uyy
,.,.,.:2y.y,.:.
':":"y2U
1UJ
':-y-2uyy
—;;-2U"..<'
':":"y-2uyy
1.4J
':":-y-2Uy.::
,.,.,.,?2y,
2-Prnnennir ariH 9-mpthwl- mpthwl pctp
11J
1U.- y
11J
11)
11)
11)
11)
111
11)
11)
iu -yy
;iy'-:..y
yyy-iy,-'-;,:-
111
11)
111
11)
1U
; 1U y
-.-.y iu
'-':iu
—yiu. •; •
1U
y.ymy..>
•v;HU"
1U
y,-yiy'"
- 1U
y 1U
1U
1U
IU :
1U ~
-•y -40"-y,--
y W'A
. 1UJ "•
-.-y*iy--y
1U
1U
1U
1U
1U
Benzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2.5
5.1
1U
1U
1U
1U
50U
2
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, (1-methvlethvD-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
5.2
5.1
1U
1U
0.86J
0.91 J
51
1.6
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, 1,2,4-trimethyl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
58
38
1U
1U
5.7
6.2
370
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, 1,2-dichloro-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
8
7.6
1U
1U
1U
1U
47 J
11
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene. 1.3.5-trimethyl-
1U
1U
1U
1U
lid
1U
lid
1U
IU
1U
IU
1U
IU
1U
IU
1U
IU
17
-7S.
1U
IU
1U
iy
170
1U
IU
iy
IU
iy
IU
iy
IU
iy
IU
1U
Benzene. 1.3-dichloro-
v--yiU"-y-
—;4j/y
':":":"Mld,
:;I' 1 ;U ; ;'*
':":":"Mld,
1U
':":":">lUy'
':":":yiuy
-"vy.yly.
':":":yiuy
':"y-iy y.;:
'""yviuy
':''y-iyyy
':":"y-iuy
':":-yiy -:y
'""yviuy
':''y-iyyy
Benzene. 1.4-dichloro-
1U y-.
1U .- y
yyyiyy.y
1U
yysy'y
yy^y^r.v
•¦y ®vy
1.1
¦•y:rf/y.
y-/'
0.9J
1U
>--;y:au
1U
y;;:fly:yy
1U
>--;y:au
1U
y;;:fly:yy
Benzene. 1-methvl-4-( 1-meth vlethyl)-
1U
-.-.y iu
Iti v
y.-<-.iy;y
AlU:;;- y
^Htf.'y
y-./itik- v
:Aw.'-y
0.96J
0.84J
' ' 0.85J y
1U -y
1U .-"
y-CU:;.:- -;...
1U ;
v
y.yiyy,
1U ;
v
Benzene, chloro-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2.1
3.1
1U
1U
IU
IU
IU
IU
IU
IU
IU
IU
1U
Benzene, ethenvl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2
1.5
1U
1U
1U
1U
40J
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, propvl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
7
8.4
1U
1U
1U
1U
22J
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, tert-butvl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1.1
1.1
50U
1.3
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Bromobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Bromochlorom ethane
1U
1U
1U
1U
lid
lid
lid
1U
ethane
AAW-S'-
—>1U.;".,<
-y-iu-yy
':":":"Mld,
':":-ylU"
':":":"MU,
':":"y:,iuy,
':":-yiy
':":"y:,iuy,
—:iyy-.:.-
':":"y:,iuy,
':":-yiy
':":"y:,iuy,
':":-yiy" yy
':":":"y.iyy,.'--:'.:
Bromoform
1U y-.
1U .- y
yyyiyy.y
1U
yysy'y
1U
y.;;:flia:yy
••y »yy
••y ?tu
1U
>y.:au
1U
y;;:iy:yy
1U
>y.:au
1U
yyyiyyy
>'•-?. iu y
Bromomethane
1U
-.-. y.-2idyy
2U
2yy-,
=.
1U ;'
--::€&,yy
2U y-
yyiuy y
yfuy y
yyi,Us;' y
.y-iir/y
yyiy --'v
2U
1U ?
1U
iu yy
y..yiy ^
1U ?
1U
2U :-;.v
¦y.-.'-iy
oarDon aisuiTiae
' 1U
•••' 1U
1U
A- 1U
v.: 1U
V-tll-v" '
1U
1U
•>:. •; 1U
1U
,y iu
1U '
\ - 1U ~
y,;i,UA
1U
y,;id.. y
1U '
-.v'ytuy. --
1U
y iu.- .-
y iu y.
- •. -:-;iy-y -
y iu.- .-
y :iu./\y
1U A- -
..
..
..
..
..
..
..
..
..
..
1U
..
..
..
..
..
..
..
1U
..
1U
...
..
..
..
..
..
..
..
..
..
..
..
..
cis-1,2-Dichloroethene
70
1U
1U
7.2
1U
0.84J
1U
1U
1U
1U
1U
210
1.5
1U
1U
24
75
270
2200
2200
1100
1100
1U
1U
69
2100
190
36
1U
17
1U
2.1
1U
1U
6
1U
1U
cis-1,3-Dichloropropene
1.1U
1.1U
1.111
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
53U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
Dibrom ochloromethane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Dibrom om ethane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Diethyl ether
1U
.lid
lid
lid
lid
1U
lid
lid
IU
1U
IU
1U
IU
1U
IU
1U
IU
1U
IU
1U
lid
IU
iy
50U ....
iy
IU
iy
IU
iy
IU
iy
IU
iy
IU
1U
Ethane. 1.1.2.2-tetrachloro-
v-yw-y-
"''y-iy yy
0.85J
-y-iu-yy
190J
':":":"MU,
':":":"MU,
':":"y3,;3'.A:"'
,.,.,.,20/.-.
w;> ST
29
1.6
1.2
50U
":":":';-22y,y
':":'y-3^-'..-y
'""yviuy
':''y-iyyy
'""yviuy
':"y-iy y.;:
'""yviuy
iy :'*
jy,,:.
Ethane. 1.2-dibromo-
1U y-.
1U .-
-tu'
vyiuy
••y »yy
-y iu
yy;iyyv
1U
1U
1U .••••
1U
>y;iU': -v
1U ^y
;y.,ild v'-.
.-^iijy y
yy-® -y:'-.
1U
y;;:fly:yy
1U
>--;y:au'
1U
y;;:fly:yy
-,1U.-
1U
-.-. 0.82J
2.4
..'"¦yiy-
150 ••
1U
.\v"iyy..;.
14
y.>:4i:;.
' 1400
1400 •
360 y
'•f iu - y
34J -y
y 170 --
100
yy2»y-.<-
:-y--5is'- -"
yew-., v
y.yiyy,
•y-~ 1U ;"
-yi^ --y
yy-iy.y -
- -1;®-""-"..-'
8.9
y :-y3;y •••
• y2i.y'
yy:is:!
1100
:'2:1"y
•:ya®-A~'
"'y\73"...y/;
200
100
yyii y
1300 .>
yy '
50U
190
79
• 15 ---,
1U
1U y
1U
y«..,-v-
y
y iu
Ethvl Chloride
IU
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Ethylbenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
45
34
1U
1U
1U
1U
150
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Ethylmethacrylate
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Freon 11
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1UJ
1U
1U
50UJ
1UJ
1UJ
1UJ
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
l.ld J
1..U.J ....
lid
1U
lid
1UJ ....
IU
1UJ ....
IU
1U
IU
1U
lid
iy
IU
iy
IU
iy
1U
Furan. tetrahvdro-
AAW-S'-
—,;SO
¦y-iSi^y.y
—;..gyyy
1U
':":":"Mld,
-y-iu-yy
—;;si^--y,r
1U
—::;SldA:.V'
1U
':":":"MU,"'.;">
"-y-iuyy
':":":"MU,
':":"yiu,y--:'
'""yviuy
':''y-iyyy
'""yviuy
':"y-iy y.;:
'""yviuy
''':'':'^;:,iuyy
-lexacniorouuiauiene
1U y-.
'.y.tji
1U yy
1U v;.
¦"1
1U :-f
-•y ;w\"/
-ild
1U
1U \
41 1
\yy-iu
; 1U
y;,-':iy :-f.y
-•y iu
; 1U :-f
¦" •
y.-'iu'
yy.iix -v...:-
.<--"...luy y
y;;:fly:yy
>--;y:au'
HI I
HI 1
Hexachloroethane
;"2Uyy
iu y;
': 1U y. y
iu y
1U
1U
1U
1UJ
1UJ
2U ;"
-•:;2ijy,y
2U
y-- 2U ;"
Vlethacrylonitrile
¦
yymjyy
2U y
>v~ Sia?"y
2U
2U
2U
yy:'2yy
y--"tyv'-'-
2U
:yiu -y ---
1U
1U
\y:iM.: y
1U
1U
Vlethane, chloro-
1U
1U
1U
Vlethane, trichloro-
1U
1U
1U
1U
0.83J
2.6
1U
1U
1U
1U
1.3
1U
1U
1U
0.48J
1.2
0.82J
1.3
1.5
1U
1U
1U
1U
50U
6.1
8.6
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethyl acrylate
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethyl Iodide
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1UJ
1U
1U
50U
1UJ
1UJ
1UJ
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethyl tert butvlether (MTBEj
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
50U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethylene Chloride
1U
.lid
lid
lid
lid
5.2
1U
IU
1U
1U
1U
IU
IU
iy
iy
IU
IU
iy
iy
1U
VlP-Xylene
*;y,2U''-y-
,.,.,..,^y ,
:.,.,.,.,.2y
gy , ,/
W;>2U
':":"y2tJ'
—v;"-
W;>2U
,.,.,.:2y.y,.:.
,.,.,.:2y.y,.:.
96
':":":;>3;1 ~-y
':":":;>2U'
":"":"y-2uyy
600
yy
':":"y-aj.y-y-
yy
':":":::-2yy.,-:'
,.,.,.,?2y ,
Maphthalene
1U
y-y-iy
yyyiyy
1U .-
1U
y.y# =y-
1U
:y 1U y-.-'
1U
yy-iu Iv
1U
"|yyv
1U
yyfu y-?'
1U
a- "|yyv
1U
yysF: '-?
y;. ;tl
.viu y-?'
•A:yiy;"'.y.
4.2U
4.4U
160U
1.1U y
'^yiyy-?'
•-yiily •-
yy..iy -y,?'
•-'yyiy;"-.y.
yy'|y y-?
--y -i.y >-y
yyitfy :v
yy~id:y-i-
yyyiy-yk
yy id y
>Butvlbenzene
; 1U y
v. yyiu -v-:
-y.-iy-yy
1U
y:'"
1U -
1U
1U C'
y-.ytu -yr
1U
1U
y.ytu 'yr
•:y.ild',:'.k
1U
1U
y.ytu -yr
•••-. 1.6 "
1U C'
yv:4U'- y
yyiid.y-
r'-y,W.v -
iu y
y-.-:4y;' y
yyw c-
y-,-:.iyy
1U
y,-:.4iyy -
111
-;-yiy" -y
111
y,->iy?y
- 1U
y 1U y
:y :AUAA
A- 1U •> v
1U
1U v..
: v. iu -•
•a
1U
'A'l
1U
yrM y
1U >,
'A't
1U
yrM y
1U >,
43
1U
1U
y-.:yfiy--
A,
yysnoy-
1.1 -
iu y
-,-iyy. y
yyyiyy -
1U
:y-Aii|y
1U
1U -
yy-iyy.-
1U v'- '
1U
Pentachloroethane
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
50U
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
sec-Butylbenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1.8
2
1U
1U
1U
1U
38J
3.3
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Tetrachloroethene
1U
1U
1U
1U
1U
2.2J
1U
1U
1U
1U
36
1U
1U
17J
1.9
9.7
6.2
2.9
4
3.8J
4.4J
2J
1.8J
50U
42J
28J
2.1J
1U
1U
1U
1U
1U
1U
1U
1U
Toluene
1U
1U
1U
1U
1U
2.1
1U
1U
1.6
1U
1U
1U
1U
1U
1U
1U
1U
94
81
1U
1U
1U
1600
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Trans-1.3-Dichloropropene
0.94U
0.94U
0.94U ...
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U ..
0.94U
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ..
0.94U
0.94U ...
0.94U
:rans-1,4-Dichloro-2-butene
5UJ y
y 5UJ -y.
yy-^tfjy y
5UJ ".
5UJ y
y;..:5li4yy
5UJ yy
yystir-y
5UJ
yyei^'-y
5uj y.
yyei^'-y
5uj y
yyei^'-y
5uj y
yysliry
5UJ
yysliry
5uj y
yyei^'-y
5uj y
5UJ
5UJ
5UJ -y
y/sttjy
5UJ yy
y/sttjy
5uj y
5UJ
5UJ
5UJ
yiuy,?
y; yt.6y^
1U
1U \ a
."A:iyAy,
y:.-:iy-y^
1U v"
1U
. - - ijj jyy
4.7
. - - ijjyy
. - - ijjyy
. - -'CS-" y."
21
. - afcr'v
" 330
. - "&y •
. - -lij-yy-
91
- .1:5.-:--.y
•.y-:.'l;7.-v- ;
1U yr.
.-21
- -ILJ-yy-
iu y,-.
- 0.81 J -.
yjyisu y y
.
: 0.2U
0.2U v:
0.2U
0.2U
0.2U //
0.2U -
0.2U
0.2U
¦r-; 0.2U
0.2U
-y.&,'2wy"
0.2U
0.2U
0.2U
0.2U ~
0.2U
V 0.2U
•j 0.83 -y
.••yiwc-.
1U
0.94U ;
y' 0.36 '•
- - 0.2U
0.2U y
0.2U
y 0.2U
0.2U
0.2U -
- 0.2U y.
o.2u y.
TPH-GC/Motor Oil Ranae Oraanics
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
580000
0.49U
0.49U
0.49U
0.49U
0.49U
0.51U
0.5U
0.49U
0.49U
0.49U
0.49U
0.49U
Jnleaded gasoline composite
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
2200J
1200
50U
50U
190
210
11000
490U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
Notes: U= The analyte was not detected at or above the reported value. *For 1,4-dioxane and 1,1,2,2-tetrachloroethene, MCLs were unavailable and
J= The identification of the analyte is acceptable; the reported value is an estimate. Oak Ridge National Laboratory (ORNL) values as of 6/22/2008 were used instead.
CDM
Well 12A Final FFS April 2009
Page 1 of 2
-------
Table 2-5
Well 12A Analytical Data from February/March 2008
Analyte
MCL
(uq/L)
MW-B
MW-C
TOW-4
TOW-10
TWT-10
WCC-1A
WCC-1B
WCC-2
WCC-3
WCC-5-1
WCC-5-2
WCC-6
WCSB-9-1
WCSB-9-2
Well 11A
Well 12A
Well 9A
1,4-Dioxane (SVOC)
6.1
1U
1.2
1.1
14
1U
57
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,1,1,2-Tetrachloroethane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,1.1-Trichloroethane
1U
1U
l id
1U
.lid
1U
.lid
1U
.lid
1U
.lid
1U
1U
1U
1U
1U
1.1,2-T richloroethane
-A-W-'.r-
W'M „1
1.9
,.,.,.:1ld ."
0.88J /:
'""'•llU";::
1.1-Dichloroethane
1U
1U
1U
A^W^-7
••X: ?tu
yyiy-fy
••X: ?tu
••X:
•A'V.ioh-,...
•-v.-
1U
• 1.6 "v'
¦K- 1U
1U
1U
1.1-Dichloropropanone
' 'StTC.'
1U -r
v. 2U
'Vx.2id.?.r
v.;2U^
2UJ -
2U
1U >
2u y
1U
1,1-Dichloropropene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,3-Trichlorobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,3-Trichloropropane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2,4-Trichlorobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1,2-Dichloroethane
1U
1U
l id
1,2-Dichloropropane
-A-W-'.r-
I ,>uicnioropropane
1U
'..;C ty-fy
••X:
1-Chlorobutane
1U
1U
1.4
2,2-Dichloropropane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2-Butanone
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
3.7
1U
1U
1U
1U
1U
1U
2-Chlorotoluene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
2-Hexanone
1UJ
1UJ
1U
1U
1U
1U
1UJ
1UJ
1U
1UJ
1UJ
1UJ
1UJ
2-Pentanone. 4-methyl-
1U
1UJ ....
lid
1U
.lid
1U
.lid
1UJ ....
lid
1U
1UJ
lid
1UJ ....
lldJ ....
2-Propanone
*;A2ld"y;"-
1.1J
':":":;>2U
':":":";2ld,
W;>2U">-::
0.88J
1.6J
iQ;..,'
2-Prnnennir ariH 9-mpthwl- mpthwl pctp
11J
-i
11)
111
111
V, 1U
lid'-::-'-;
1U
''.-V;y:"1.y
-y./.yl.U'X"".
; 1U
^.:iy-"A"
1U
1U
1U
- 1U
1UJ
1UJ r.
1U .,
1U /:::
1U -
1U
1U
Benzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, (1-methylethyl)-
1U
1U
1.5
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1UJ
1UJ
Benzene, 1,2,4-trimethyl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, 1,2-dichloro-
1U
1U
2.3
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene. 1.3.5-trimethyl-
1U
2U
.lid
lid
.lid
lid
.lid
1U
.lid
21d
.lid
1U
21d
1U
21d
21d
Benzene. 1.3-dichloro-
AAW-s'-
wylU,-v:
wylU,-v:
---Vlldyy"-:
Benzene. 1.4-dichloro-
1U
1U
>v-:au
1U
A^W^-7
1U
/•' /iy y>?
1U
Benzene. 1-methvl-4-( 1-methvlethvl)-
1U
1U ;'
1U
v; 1U
yiij-y
:''iu
;;;:;.5Ud.^.v
Benzene, chloro-
1U
IU
IU
IU
IU
IU
IU
1U
1U
1U
IU
1U
1U
1U
1U
Benzene, ethenvl-
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Benzene, propvl-
1U
2U
1U
1U
1U
1U
1U
1U
1U
2U
1U
1U
2U
1U
2U
2U
2U
Benzene, tert-butvl-
1U
1U
1.1
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1U
Bromobenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Bromochlorom ethane
1U
m
.lid
lid
ethane
AAW-S'-
':":":":M;ld"
Bromoform
1U
1U
1U
>v-:au
1U
1U
>v-:au
Bromomethane
1U
~ MU-"'-
v
1U
1U ;'
v
1U
1U
v
1U
Jy.y;2ld:'y', -
oarDon aisuiTiae
' 1U
1U
1U
1U
1U
V-tll '
1U
1U
1U
1U
1U ,V;
;a 1U >
iid>"s\
•" 1U
..
..
..
..
..
..
..
..
..
..
..
..
..
..
1U
..
cis-1,2-Dichloroethene
70
1.2
89
280
1U
1U
5.6
74
1U
1U
4.5
1U
1U
0.94J
1.2
1U
1U
1U
cis-1,3-Dichloropropene
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
1.1U
Dibrom ochloromethane
1U
2U
1U
1U
1U
1U
1U
1U
1U
2U
1U
1U
2U
1U
2U
2U
2U
Dibrom om ethane
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Diethyl ether
1U
m
.lid
1U
.lid
1U
.lid
1U
.lid
1U
.lid
1U
1U
1U
1U
1U
Ethane. 1.1.2.2-tetrachloro-
AAW-S'-
—;>3@V",<
w>3rl ~--r-
63J
'""'•llU";::
—ylld" • = <•?
Ethane. 1.2-dibromo-
1U
A
1U
yyiy-fy
1U
••X: ?tu
•A'V.ioh-,...
•¦AWK.-y
•-v.-
0.98J
82
\s2S£t: 'j
¦.v-SfrV-"-'
1U v
1U
1U
- •
260 y
59
15 i
92
>.-AMr. -
0.15J
45
'".V'Cld, ..
1.4
1.2
Ethvl Chloride
IU
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Ethylbenzene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Ethylmethacrylate
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1UJ
1UJ
1UJ
Freon 11
1U
1U
1UJ
1U
1U
1U
1UJ
1U
1U
1U
1UJ
1U
1U
1UJ
1U
1U
1U
1U
1U
.lid
Furan. tetrahvdro-
AAW-S'-
1UJ <•
W;;-5U"
-lexacnioiouuiauiene
1U ".y:
1U
•<"=?¦
;;;.::10/:'
.<>r Htjf.
Hexachloroethane
;"2U\y
5U
1UJ
5U
1UJ
v:- 1U
Vlethacrylonitrile
-
'••• 1U
v.SO", v..
1U
1U
1U
v.SO", v..
2U
Vlethane, chloro-
1U
Vlethane, trichloro-
1U
1U
1U
1U
1U
1U
0.84J
1U
1U
2.3
1.9
2.9
1U
1U
0.85J
1U
1U
Vlethyl acrylate
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethyl Iodide
1U
1U
1UJ
1U
1U
1U
1UJ
1U
1U
1U
1UJ
1U
1U
1UJ
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Vlethylene Chloride
1U
m
1U
.lid
1U
4,1
1U
1U
1U
VlP-Xylene
':":":";2ld,
':":":;>2U
':":":";2ld,
...
—;;2y¦• = <•?
;2yy y.
Maphthalene
1U
1U v -j
1U
"Jy v?
1U
1U
1U
V:,.;:rCU".
..y'AWAf
"V.-iycv
1U
>Butvlbenzene
; 1U
'I'iu.. v>
~ 1U -
1U
'-/T
-:yMyV;y:'
1U
1U
'-/r
1U
v.-.
. ¦
- 1U
.v.
; 'S'M A
1U >,
¦A-1UA-:
1U
\':'M A
1U >,
'A't
1U
:,H- 1U
A:>
yll$AA.
1U •• i
Pentachloroethane
1UJ
5UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
1UJ
5UJ
1UJ
1UJ
5UJ
1UJ
5UJ
5U
sec-Butylbenzene
1U
2U
0.92J
1U
1U
1U
1U
1U
1U
2U
1U
1U
2U
1U
2U
2U
Tetrachloroethene
1U
8.8J
2.4J
1U
1U
1U
2.2J
1U
1U
1.4J
1U
1U
4.3J
6.6J
1U
1U
Toluene
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
1U
Trans-1.3-Dichloropropene
0.94U
0.94U ..
0.94U
0.94U
0.94U ..
0.94U
0.94U
0.94U ..
0.94U
0.94U ...
0.94U
0.94U ..
0.94U
:rans-1,4-Dichloro-2-butene
5UJ
dfi.
5UJ
5UJ
sCm
5UJ
2U
yvskla-.-'',.
5UJ
2U y
5UJ
2U
140
1.6
-
. - 1.1
. - -tU'vv
•' ,fid:;/>."
.?^;U;y..x
r.'ii'y
iu -•
1U
.
: 0.2U
0.2U V;
». 0.2U
0.2U .•/
0.2U
: 0.2U
0.2U -
\ 0.2U
0.2U
-
0.2U >
0.19U
0.19U
0.19U
TPH-GC/Motor Oil Ranqe Orqanics
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.49U
0.46U
0.46U
0.46U
Jnleaded gasoline composite
50U
50U
120U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
50U
Notes: U= The analyte was not detected at or above the reported value. For 1,4-dioxane and 1,1,2,2-tetrachloroethene, MCLs were unavailable and
J= The identification of the analyte is acceptable; the reported value is an estimate. Oak Ridge National Laboratory (ORNL) values as of 6/22/2008 were used instead.
CDM
Well 12A Final FFS April 2009
Page 2 of 2
-------
Table 2-6
Contaminant Volume and Mass Estimate - March 2008
Dissolved Groundwater Plume
Concentration
(Hg/kg)
Cis 1,2 DCE
TCE
Aquifer*
Volume
(acre-feet)
Chemical Mass in
Groundwater
(ka)
Aquifer*
Volume
(acre-feet)
Chemical Mass in
Groundwater
(ka)
>200
159
38
220
70
>300
119
34
135
64
>500
72
28
89
58
>1000
24
15
51
47.7
Total Indicator VOCs
1,4 Dioxane
Concentration
(Hg/kg)
Aquifer*
Volume
(acre-feet)
Chemical Mass in
Groundwater
(ka)
Aquifer*
Volume
(acre-feet)
Chemical Mass in
Groundwater
(ka)
>200
471
197
35
37
>300
346
186
13.6
1.8
>500
238
170
NA
NA
>1000
143
146
NA
NA
* Soil porosity = 30%
Table 2-7
Contaminant Volume and Mass Estimate - Soil Plume
Concentration
(Hg/kg)
PCA
TCE
Volume
(cubic-yards)
Chemical Mass in
Soil
(ka)
Volume
(cubic-yards)
Chemical Mass in
Soil
(ka)
>1000
33,886
416
38,940
1,014
>3000
16,740
375
18,920
966
>5000
11,890
349
13,590
937
>10000
6,417
293
8,250
882
Conentration is the isoconcentration that defines the plume for the estimates
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Table 2-8
Comparison of Contaminant Mass in Soil Samples
Above and Below the Water Table
Above Water Table
Compound
and Sample
Set Dates
Isovolume Level
(ug/kg)
Total Soil
Volume
(cubic yards)
Total Soil
Mass
(kg)
Chemical
Volume
(cubic yards)
Chemical
Mass
(kg)
TCE
(1985-2004)
1.00E+03
1.25E+04
1.77E+07
4.62E-01
3.53E+02
PCA
(1985-2004)
1.00E+03
1.98E+04
2.79E+07
3.63E-01
2.77E+02
cis 1,2 DCE
(2004)
1.00E+03
1.07E+02
1.52E+05
2.76E-04
2.11E-01
PCE
(1997-2004)
1.00E+03
1.71E+03
2.43E+06
8.31 E-03
6.35E+00
trans 1,2 DCE (1985-2004)
1.00E+03
2.35E+05
3.32E+08
2.93E+00
2.24E+03
Below Water Table
Compound
and Sample
Set Dates
Isovolume Level
(ug/kg)
Total Soil
Volume
(cubic yards)
Total Soil
Mass
(kg)
Chemical
Volume
(cubic yards)
Chemical
Mass
(kg)
TCE
(1985-2004)
1.00E+03
3.66E+04
5.17E+07
8.97E-01
6.86E+02
PCA
(1985-2004)
1.00E+03
2.71 E+04
3.84E+07
2.33E-01
1.78E+00
cis 1,2 DCE
(2004)
1.00E+03
1.02E+03
1.44E+06
6.53E-03
4.99E+00
PCE
(1997-2004)
1.00E+03
1.07E+04
1.51E+07
9.26E-02
7.08E+01
trans 1,2 DCE (1985-2004)
1.00E+03
1.52E+05
2.15E+08
2.88E+00
2.20E+03
Isovolume level identifies the minimum plume concentrations for which the calculations were made
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Table 3-1
Chemical-Specific ARARs/TBCs
Matrix
Standard, Requirement,
Criterion, Or Limitation
Citation Or Reference
Description
Status
Comments
FEDERAL
Soil
EPA Soil Screening Guidance
EPA/540/R-96/018
Provides methodology for calculating
risk-based, site-specific soil screening
levels.
TBC
Used to standardize
and accelerate site
cleanup.
Groundwater
Maximum Contaminant Levels
(MCLs)
40 CFR 141.61-65
MCLs regulate concentration of
contaminants in public drinking water
supplies but may also be considered for
groundwater aquifers used for drinking
water.
Relevant and
Appropriate
Relevant to VOCs
and metals in
groundwater.
Maximum Contaminant Levels
Goals (MCLGs)
40 CFR 141.50-54
MCLGs are health-based criteria that
should be evaluated for groundwater
contamination.
Relevant and
Appropriate
Relevant to
contaminants in
groundwater.
Guidance on Remedial Actions for
Contaminated Groundwater at
Superfund Sites
EPA/540/G-88/003
Provides information on remedial
technologies to address groundwater
contamination.
TBC
Relevant to
contaminants in
groundwater.
Guidelines for Groundwater
Classification Under the EPA
Groundwater Protection Strategy
813R86001
(nepis.epa.gov)
Presents guidelines for classifying
groundwater in one of three
classification categories based on
ecological importance, replaceability,
and vulnerability considerations
TBC
Useful in identifying
ARARs and
establishing cleanup
goals for site
groundwater based
on policy that different
groundwater merit
different levels of
protection.
Surface Water
Clean Water Act, Ambient Water
Quality Criteria (AWQC)
40 CFR Part 131
Establishes Federal AWQC for
restoration and maintenance of
chemical, physical, and biological
integrity of the nation's surface waters
Relevant and
Appropriate
Relevant to remedial
actions impacting
contaminant migration
to surface water and
groundwater.
Clean Water Act - Pretreatment
Requirements
40 CFR Part 403 and
405-471
Establishes pretreatment requirements
for discharge to POTW.
Applicable
Applicable to remedial
actions involved
discharge to a POTW.
CDM
Well 12A Final FFS April 2009
Page 1 of 2
-------
Table 3-1
Chemical-Specific ARARs/TBCs
Hazardous
Waste
Resource Conservation and
Recovery Act (RCRA) -
Identification and Listing of
Hazardous Waste
40 CFR Part 261-265,
270, and 271
Defines those solid wastes which are
subject to regulations as hazardous
wastes, and lists specific chemical and
industry-source wastes.
Applicable
Applicable to
determining whether
remediation wastes,
such as spent carbon,
are considered
hazardous under
RCRA.
RCRA - Part 268 Land Disposal
Restrictions
40 CFR Part 268
Establishes standards for land disposal
of RCRA hazardous waste. Requires
treatment to diminish a waste's toxicity
and/or minimize contaminant migration.
Applicable
Applicable if remedial
activities include land
disposal of RCRA
hazardous waste,
such as that
generated from
excavation of waste
that is characterized
as hazardous
Other
Oak Ridge National Laboratory
Screening Criteria
http://epa-
prgs.ornl.gov/chemicals/i
ndex.shtml
Establishes regional chemical screening
levels to be used in risk assessments
TBC
May be considered in
development of
cleanup goals.
WASHINGTON
Model Toxics Control Act (MTCA)
MTCA clean up
regulations (WA 173-340)
Establishes the methods to determine
cleanup standards for soil, groundwater
and surface water
Applicable
Water Pollution Control Act
Water quality standards
for groundwater of the
State of Washington
(WAC 173-200)
Establishes groundwater quality
standards, which together with
technology-based treatment standards
provide for protection of existing and
future use of groundwater. Not directly
applicable because it specifically does
not apply to clean up actions approved
by Ecology under MTCA.
Relevant and
Appropriate
CDM
Well 12A Final FFS April 2009
Page 2 of 2
-------
Table 3-2
Location-Specific ARARs/TBCs
Standard, Requirement, Criterion,
Or Limitation
Citation Or Reference
Description
Status
Comments
FEDERAL
Surface Water:
Federal Ambient Water Quality
Criteria
40 CFR 131
Establishes cleanup levels for surface water.
TBC
May be TBC if contamination of
surface water is suspected.
Groundwater:
Groundwater Classification
Guidelines
N/A
Presents guidelines for classifying groundwater
in one of three classification categories based
on ecological importance, replaceability, and
vulnerability considerations.
TBC
Useful in identifying ARARs and
establishing cleanup goals for
site groundwater based on
policy that different ground
waters merit different levels of
protection.
WASHINGTON
None Identified
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Table 3-3
Action-Specific ARARs/TBCs
Matrix
Standard, Requirement,
Criterion, Or Limitation
Citation Or Reference
Description
Status
Comments
FEDERAL
Air
Clean Air Act
42 USC 7401, Section
1 12
Establishes limits on pollutant
emissions to atmosphere from
specific industrial and commercial
activities. Establishes standards to
protect public health and welfare, and
ambient air quality.
Relevant and
Appropriate
Some groundwater treatment
alternatives may impact ambient air
quality.
National Ambient Air
Quality Standards
(NAAQS)
40 CFR Part 50
Establishes primary and secondary
NAAQS in Section 109 Clean Air Act.
Applicable
Applicable to groundwater treatment
alternatives that may emit pollutants
to the air; establishes standards to
protect health and welfare.
National Emission
Standards for Hazardous
Air Pollutants (NESHAPs)
40 CFR Part 261
Establishes specific emissions levels
allowed for toxic air pollutants.
Applicable
Applicable to groundwater treatment
alternatives that may emit toxic
pollutants to the air.
Surface Water
Clean Water Act and
NPDES
Requirements
40 CFR 122-125
Regulates discharge of pollutants
into navigable waters
Applicable
Substantive requirements will be
applicable to any alternative that
discharges effluent to surface water.
Clean Water Act
40 CFR 136
Identifies test procedures to measure
specified waste constituents under
the NPDES or otherwise, shall be
conditioned so that the discharge
authorized will meet water quality
standards.
Applicable
CDM
Well 12A Final FFS April 2009
Page 1 of 4
-------
Table 3-3
Action-Specific ARARs/TBCs
Matrix
Standard, Requirement,
Criterion, Or Limitation
Citation Or Reference
Description
Status
Comments
Groundwater
EPA Underground
Injection Control
(UIC) Program
Regulations
40 CFR 144 and 146
Regulates injections into
underground sources of drinking
water by specific classes of injection
wells.
Relevant and
Appropriate
Relevant to any in-situ remediation
technologies that involve injection
into the drinking water aquifer.
Transportation of
Hazardous Wastes
49 CFR 170-189
Federal Highway Administration,
Department of Transportation
National Highway Traffic Safety
Administration regulations are
codified in 23 CFR Parts 1-1399.
Applicable
Applicable to remedial activities that
involve the off-site transportation of
hazardous waste.
WASHINGTON
Hazardous
Waste
Ecology Dangerous
Waste Regulations
WAC 173-303-141 to
270
Establishes guidelines for Treatment,
storage and disposal and
transportation of Dangerous waste
Applicable
Applicable to hazardous materials
generated at the site.
Ecology Dangerous
Waste Regulations
WAC 173-303-080 to-
100
Establishes guidelines to determine
dangerous waste lists,
characteristics, criteria
Applicable
Applicable to hazardous materials
generated at the site.
Land Disposal
Restrictions
WAC 173-303-140
Establishes standards for land
disposal of Ecology dangerous
waste.
Applicable
Applicable if remedial activities
include land disposal of Ecology
dangerous waste.
Surface Water
Water Pollution Control
Act
WAC 173-201 A; WAC
173-220;
Establishes water quality standards
for surface waters of the state.
Waste discharge permits, whether
issued pursuant to the NPDES or
otherwise, shall be conditioned so
that the discharge authorized will
meet water quality standards.
Relevant
Substantive requirements will be
applicable to any alternative that
discharges effluent to surface water.
CDM
Well 12A Final FFS April 2009
Page 2 of 4
-------
Table 3-3
Action-Specific ARARs/TBCs
Matrix
Standard, Requirement,
Criterion, Or Limitation
Citation Or Reference
Description
Status
Comments
Groundwater
Water Quality Standards
for Waters
WAC 173-201
Effluent must meet water quality
standards
Relevant
In the absence of an MCL or ambient
WQC, EPA Region 10 conducted a
risk assessment of the chemical and
provides an appropriate treatment
goal for the protection of public
health, welfare and the environment.
State Waste Discharge
Program
WAC 173-216
Must meet pre-treatment regulations
as revised for operations of the
secondary sewage treatment plant.
Applicable
Applicable if the option of discharge
to the sanitary sewer is chosen, it
must be consistent with discharge
limitations.
Air
Washington
Environmental
Quality law
WAC 173-400
General Regulations for Air Pollution
Sources
Applicable
Substantive requirements will be
applicable if alternative results in
emissions from groundwater
treatment processes.
Washington Clean Air Act
WAC 173-460
Controls for New Sources of Toxic
Air Pollutants
Applicable
Washington Clean Air Act
WAC 173-470
Ambient air quality standards
Applicable
State Environmental
Policy Act (SEPA)
WAC 192-11
Requires a review of potential
damage that occurs to the
environment as a result of man's
activities. SEPA checklist may be
required prior to construction of the
remediation system.
Applicable
LOCAL REGULATIONS
CDM
Well 12A Final FFS April 2009
Page 3 of 4
-------
Table 3-3
Action-Specific ARARs/TBCs
Matrix
Standard, Requirement,
Criterion, Or Limitation
Citation Or Reference
Description
Status
Comments
City of Tacoma
Establishes criteria for review and
analysis of all development, including
grading, erosion control, and property
development. Requires permits for
excavation of soil in excess of 50
cubic yards and construction and
demolition activities. SEPA checklist
required if soil excavation is greater
than 500 cubic yards. Permit required
for connection if effluent water from
the treatment system to the storm
drain system. Even though it is
necessary to meet the substantive
provisions of these permits,
appropriate permits should be
obtained from the City for future site
work in the spirit of cooperation.
Applicable
Tacoma Power
Permits required for temporary power
connections and wiring for
remediation systems.
Applicable
CDM
Well 12A Final FFS April 2009
Page 4 of 4
-------
Table 4-1
Summary of Cost Estimates for Remedial Alternatives
Alternative
Alternative Name
Total Capital Cost
Annual O&M Cost
Present Worth
Filter Cake and Shallow Impacted Soil
FC1
No Action
$0
$0
$0
FC2
Institutional Controls
$30,600
$39,000
$114,800
FC3
Capping Contaminated Soils In Place
$798,100
$75,400
$1,267,300
FC4
Excavation of Soils, Transportation to
and Disposal in RCRA Subtitle C or D
Landfill
$2,346,500
$68,900
$2,801,700
Deep Vadose Zone Soil and Upper Saturated Zone East of Time Oil Building
SG1
No Action
$0
$0
$0
SG2
Institutional Controls
$30,600
$39,000
$114,800
SG3
Insitu Thermal Remediation
$4,106,200
$110,500
$4,662,000
High Concentration Groundwater
HG1
No Action
$0
$0
$0
HG2
Institutional Controls
$61,300
$52,000
$173,500
HG3
Extraction and Treatment with GETS
$30,600
$339,300
$3,708,000
HG4
Enhanced Anaerobic Bioremediation
$2,423,900
$408,200
$4,217,700
HG5
Enhanced Anaerobic Bioremediation
plus Air Sparging and Soil Vapor
Extraction
$3,344,800
$545,100
$5,275,500
Low Concentration Groundwater
LG1
No Action
$0
$0
$0
LG2
Wellhead Treatment at Well 12A
$341,500
$263,900
$2,094,200
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Table 5-1
Summary of Comparative Analysis of Alternatives
Alternative
Overall Protection of
Human Health and the
Environment
Compliance with ARARs
Long-term Effectiveness
and Permanence
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Short-term Effectiveness
Implementability
Present Worth
Capital
O&M
Present Worth
Filter Cake and Shallow Impacted Soil
Alternative FC1 -
No Action
None
- This threshold criterion is not
met
None
- This threshold criterion is not
met
Not evaluated
- Does not meet threshold
criterion
Not Evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
$0
$0
$0
Alternative FC2 -
Institutional
Controls
Low
- Contaminated filter cake and
shallow impacted soil would
remain in place
+ Institutional controls
restricting human exposure to
material would be
implemented
Low
- Chemical-specific ARARs
(MTCA B modified level)
would not be achieved
Low
- Institutional controls
wouldn't provide long-term
effectiveness or permanence
as contamination would
persist in filter cake and
shallow impacted soil
Low
- TMV would not be reduced
through treatment
Low Impacts
+ There would be no remedial
activities
High
+ Easily implemented because
minimal maintenance is
required
$30,600
$39,000
$114,800
Alternative FC3 -
Asphalt Cap
Medium
+ Asphalt cap would be used
as a cover reducing transport
of contaminants to
groundwater and eliminating
direct contact pathway
- Some transport to depth may
occur through vapor migration
and some minimal leaching
Medium Low
- Contaminants would most
likely persist above chemical-
specific ARARs beyond the
30-year evaluation period if no
source control is implemented
- Some transport to depth may
occur through vapor migration
and some minimal leaching
Medium High
+Reduces direct contact
- Some, but minimal, O&M
required
Medium
+ Mobility of contaminants
would be reduced
- Volume of contaminated
material would remain
- Toxicity would not be
reduced, but cap would
prevent contact
Medium
- Construction workers would
be subject to some direct
exposure risk while capping
that can be effectively
managed using standard
health and safety procedures
- Emissions during paving
would need to be managed to
prevent offsite risk
+ Approximately 1 month to
implement
High
+ Construction can be
conducted using conventional
heavy construction equipment
+ Administrative requirements
associated with this alternative
are not significant
$798,100
$75,400
$1,267,300
Alternative FC4 -
Excavation and
Offsite Disposal
High
+ All contaminated material in
zone would be excavated and
transported off site for
treatment and disposal at a
permitted facility
+ Human health and
ecological receptor risk via
direct contact with
contaminated surface soils
would be eliminated
+ All migration of
contaminants to GW and
stormwater would be
eliminated
High
+ Alternative will comply with
ARARs and RAOs
High
+ This remedy would allow for
unrestricted use at the site
+ No O&M would be required
+ No institutional controls
would be required
High
+ TMV of site contaminants
would be eliminated by
removing contaminants from
the site for offsite treatment
and disposal
Medium High
- Construction workers would
be subject to some exposure
from excavation, but can be
managed using standard H&S
procedures and protocols
- Concerns with effects on
local traffic and population due
to number of trucks leaving
site
+ Approximately 2 months to
implement
Medium High
+ Construction can be
conducted using conventional
equipment and services
- Planning will need to be
conducted prior to work to
arrange transportation
schedules
- Significant quantities of clean
material would be needed for
backfill
$2,346,500
$68,900
$2,801,700
COM
Well 12A Final FFS April 2009
Page 1 of 5
-------
Table 5-1
Summary of Comparative Analysis of Alternatives
Alternative
Overall Protection of
Human Health and the
Environment
Compliance with ARARs
Long-term Effectiveness
and Permanence
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Short-term Effectiveness
Implementability
Present Worth
Deep Vadose Zone Soil
and Upper Saturated Zone
Alternative SG1 -
No Action
None
- This threshold criterion is not
met
None
- This threshold criterion is not
met
Not evaluated
- Does not meet threshold
criterion
Not Evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
$0
$0
$0
Alternative SG2 -
Institutional
Controls
Low
- Contaminated soil and
groundwater would remain in
place and continue to be a
source for downgradient
groundwater contamination
+ Institutional controls would
restrict exposure
Low
- Chemical-specific ARARs
(MTCA B modified level)
would not be achieved
- RAO of mass reduction not
met
Low
- Institutional controls
wouldn't provide long-term
effectiveness or permanence
as contamination would
persist in soil and groundwater
Low
- TMV would not be reduced
through treatment
Low Impacts
+ There would be no remedial
activities
High
+ Easily implemented because
only minimal maintenance is
required
$30,600
$39,000
$114,800
Alternative SG3 - In-Situ
Thermal
Remediation
High
+ Continuing source to
groundwater removed or
substantially decreased
High
+ Concentrations may
decrease to below MTCA B-
levels
+ Will be designed to meet
RAO of reducing contaminant
mass by more than 90%
High
+ Reduce contaminant
concentrations in the soil and
groundwater plume
+ Source area is being
removed/reduced
High
+ Toxicity and volume of
contaminated soil and
groundwater reduced
+ Extracted VOCs would be
transferred to carbon media,
which would be regenerated
thereby permanently
destroying the VOCs
Medium
+ Treatment system could be
completed within six months of
site mobilization and the ITR
heating phase would last
approximately six months
- Medium to high risk to
workers and community since
many wells will be installed
Medium High
+ Contractors are available
that specialize in this
innovative technology
- Administrative and technical
requirements are moderately
intensive due to significant
number of wells to drill into
subsurface in area with
underground utilities
$4,106,200
$110,500
$4,662,000
COM
Well 12A Final FFS April 2009
Page 2 of 5
-------
Table 5-1
Summary of Comparative Analysis of Alternatives
Alternative
Overall Protection of Human
Health and the Environment
Compliance with
ARARs
Long-term Effectiveness
and Permanence
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Short-term Effectiveness
Implementability
Present Worth
High Concentration Groundwater
Alternative HG1 -
No Action
None
- This threshold criterion is not
met
None
- This threshold criterion is
not met
Not evaluated
- Does not meet threshold
criterion
Not Evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
$0
$0
$0
Alternative HG2 -
Institutional
Controls
Low
- Contaminated Ground water/
saturated soil would remain in
place
-Contaminants will continue to
migrate impact GW
- Institutional controls would not
be implemented to restrict future
site development/use
Low
- Chemical specific ARARs
would not be achieved
- Source materials would
continue to impact
groundwater above risk-
based ARARs
- RAO of flux reduction will
not be met.
Low
- No Action would not provide
long-term effectiveness or
permanence
- Current soil cap will not be
effective over the long term
None
- TMV of contaminants would
not be reduced through
treatment
No Impacts
+ There would be no remedial
activities, therefore no short-
term effectiveness issues
High
+ Easily implemented because
minimal action is performed
$61,300
$52,000
$173,500
Alternative HG3 -
Groundwater
Extraction and
Treatment
Medium
+ Extraction system provides
some hydraulic control;
+ Goal is to reduce contaminants
below MCL
- Some uncertainty in control at
south/southwest part of plume
-System has operated for 20
years and substantial mass still
remains
Medium Low
+ Alternative complies with
location- and action-
specific ARARs
- Contaminants would
persist above chemical-
specific ARARs within the
aquifer beyond the 30-year
evaluation period
- RAO of flux reduction will
not be met.
Medium Low
+ Zone of capture covers area
were NAPL is detected
+ Organic contaminants
would be treated
- The aquifers will not be
remediated where NAPL
remains
- Long-term O&M of the
extraction and treatment
system would be required
- Life of system may be
reached before cleanup goal
achieved
Medium
+ Mobility of groundwater
contaminants is reduced
+ Organic fraction on carbon is
permanently destroyed when
carbon is regenerated
- Only the mobile fraction of
contaminants would be treated
- Presence of NAPL prevents
reductions in toxicity and
volume
Low Impacts
+ Workers will be exposed to a
minimal risk
High
+ Easily implemented
+Treatment system already
constructed and operational
$30,600
$339,300
$3,708,000
Alternative HG4 -
Enhanced
Anaerobic
Bioremediation
Medium High
+Destruction of organics would
occur, some concentration may
remain above MCLs
+Food grade substrate will be
used therefore, groundwater
toxicity will not be increased
+ EAB can remove NAPL
Medium High
- Chemical-specific
ARARs may not be
achieved, but
concentrations will be
reduced.
+ Alternative would comply
with location- and action-
ARARs
- RAO of flux reduction will
be met
High
+ Mass will be reduced in this
source area, thus reducing
continued source
+ Organic contaminants would
be treated
+ Other than long-term
groundwater monitoring, no
O&M expected after second
amendment injection
+ Takes advantage of natural
conditions to reduce
concentrations for long-term
effectiveness
High
+ TMV of groundwater would
be significantly reduced
through treatment
+ Reductions in TMV would be
achieved for organic
contaminants
Medium Impacts
+ Each of two amendment
injection rounds are expected
to be completed within
approximately 1 -2 months
- Medium risk to workers and
community since many wells
will be installed
Medium
+Contractors are available
with this technology
experience
+Main construction component
is well installation
-Wells need to be placed on
private property and right of
ways which may be difficult
administratively
$2,423,900
$408,200
$4,217,700
COM
Well 12A Final FFS April 2009
Page 3 of 5
-------
Table 5-1
Summary of Comparative Analysis of Alternatives
Alternative
Overall Protection of Human
Health and the Environment
Compliance with
ARARs
Long-term Effectiveness
and Permanence
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Short-term Effectiveness
Implementability
Present Worth
Alternative 5 - Air
Sparging and Soil
Vapor Extraction
plus Enhanced
Anaerobic
Bioremediation
Medium High
+Destruction of organics would
occur, some concentration may
remain above MCLs
+ Aggressive AS/SVE at Time Oil
Building should remove NAPL
Medium High
- Chemical-specific
ARARs may not be
achieved, but
concentrations will be
reduced.
+ Alternative would comply
with location- and action-
ARARs
- RAO of flux reduction will
be met
Medium Low
+ Mass will be reduced in this
source area, thus reducing
continued source
- Trained staff needed for
O&M of AS/SVE
- The addition of oxygen
expected to counteract with
the anaerobic conditions, thus
reducing or eliminating the
effectiveness of this existing
natural process
Medium High
+ Toxicity and volume of
organic contaminants would
be permanently reduced
+ Organic fraction sorbed in
vapor on carbon is
permanently destroyed when
carbon is regenerated
Medium to High Impacts
+ Each of two amendment
injection rounds are expected
to be completed within
approximately 1 -2 months
+ AS/SVE will begin to remove
contaminants immediately and
is assumed to operate
approximately 4 years
- Medium risk to workers and
community since many wells
will be advanced
-Trenching for piping may
expose workers to volatiles
Medium
+Contractors available with
technology experience
+Main construction component
is well installation and piping
+As/SVE component is
located on Time Oil property
- Amendment injection wells
need to be placed on private
property and right of ways
which may be administratively
difficult
$3,344,800
$545,100
$5,275,500
COM
Well 12A Final FFS April 2009
Page 4 of 5
-------
Table 5-1
Summary of Comparative Analysis of Alternatives
Alternative
Overall Protection of
Human Health and the
Environment
Compliance with ARARs
Long-term
Effectiveness and
Permanence
Reduction of Toxicity,
Mobility, or Volume
through Treatment
Short-term Effectiveness
Implementability
Present Worth
Lower Concentration Groundwater
Alternative LG1 -
No Action
None
- This threshold criterion is not
met
None
- This threshold criterion is not
met
Not evaluated
- Does not meet threshold
criterion
Not Evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
Not evaluated
- Does not meet threshold
criterion
$0
$0
$0
Alternative LG2 -
Wellhead
Treatment
at Weld 2A
High
+ Safe drinking water supply
provided to residents
+ Institutional controls would be
implemented to protect human
health
+ Long-term monitoring would be
performed to document potential
future offsite contaminant
migration
High
+ Drinking water meets MCLs
Medium High
+ Minimal annual O&M
needed
- Stripping towers have
operated since the early
1980s and some upgrades
may be needed within 30
year evaluation period
+ Strong evidence supports
aerobic degradation is
active in low concentration
plume and will continue.
Medium
+ Mobility reduced by removing
VOCs from subsurface
+ VOCs removed from water
via air stripping
+ Aerobic degradation will also
reduce VOC concentrations in
the low concentration plume if
source removal is implemented
Low Impacts
+ Minimal exposure risk to
O&M workers
+ Sampling personnel exposed
to minimal risk
- Long-term groundwater
monitoring may continue for
more than 30 years
High
+ Treatment unit already in
place and operational
$341,500
$263,900
$2,094,200
COM
Well 12A Final FFS April 2009
Page 5 of 5
-------
Table 5-2
Alternative Groups and Cost Estimates
Group
Treatment Zones
FFS Estimate
Filter Cake and
Shallow Soil
Deep soil and high
concentration groundwater
(TCE and cis-1,2DCE > 300
ug/l) east of Time Oil Building
High concentration groundwater
(TCE and cis-1,2DCE > 300 ug/l)
groundwater west and south of
Time Oil Building
Low Concentration (TCE
and cis-1,2DCE < 300 ug/l)
groundwater
1
No Action
No Action
No Action
No Action
$0
2
Institutional
Controls
Institutional Controls
- Extraction and Treatment
with GETS
- Institutional Controls
- Wellhead Treatment
- Institutional Controls
$5.1 million
3
- Excavation
- Institutional
Controls
- In-situ Thermal Remediation
- Institutional Controls
- Enhanced Anaerobic
Bioremediation (west and south of
the building);
- Extraction and Treatment with
GETS (time limited)
- Institutional Controls
- Wellhead treatment
- Long term monitoring;
- Institutional Controls
$14.0 million
4
- Excavation
- Capping
- Institutional
Controls
- In-situ Thermal Remediation;
- Institutional Controls
- Air Sparge/Soil Vapor Extraction
(west of building)
- Enhanced Anaerobic
Bioremediation (south of building)
- Extraction and Treatment with
existing GETS (time limited)
- Institutional Controls
- Wellhead treatment
- Long term monitoring
- Institutional Controls
$16.4 million
Estimate is Net Present Worth
CDM
Well 12A Final FFS April 2009
Page 1 of 1
-------
Figures
-------
F:\Parametrix\Well12A\Figure 02 01 Site Location Map.mxd
See Figure 2-3
\\ !=
Former Time
Oil Property
Washington
Tacoma
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 2-1
Location Map
-------
F:\Parametrix\Well12A\FFS RemAlts\GIS\Proiects\FFS Final Fiqures\Fiqure 02 02 Area Map and Well Locations,mxd
CH2M-4
Center St
MW3(WCD) •
Approximate Location
See Figure 2-3
MW2 (WCD)
Approximate Location
CH2M-2
CBW-7
CBW-10
CBW-1
CBW-4
CBW-11
Legend
® Proposed Compliance Monitoring Wells
© Groundwater Monitoring Well
-(f)- Water Supply Well
WCD West Coast Door
WELL
CBW-5 USGS
CBW-2
CBW-2
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 2-2
Area Map and Well Locations
-------
MW-6
EW-18 •
EW-20
EW-19A" (9\ ®
MW-5" ® ™
EW-23
MW-1
EW-22 (•)
MW-2 *—" 7®) ^
EW-21 ™
MW-3^r ^ 0
ICF-3®
©MW-306
TOW-10
©
©
—'EW-17" (9* ®
MW-7- (g) yy
(gfW-9 EW"5(S)
^ MW-14 'B'
• Former Time Oil Building
VES Building
TOW-4
TOW-2— /
TOW-3M7 ^"13 EW"6
,JSf ® (g)
MW"9(R) B*13 MW-10 ^nmw.301 MW-18
KRRF-10 TOW-90^\ TOW-5
EW-15® EW-12(§VT^ ® ICF 5D
TOW-8 \ \
WCC-1A
WCC-1B
'
CD
CD
-t—•
CO
.CD
GETS Trailer
\
ICF-2 ©
Building Removed
February 2004
Former East Tank Farm
Filter Cake Currently Located
Beneath Concrete Pad
9°'
\9y
fiP
N
A
100
200
3 Feet
Notes:
1. Unknown well. This 4-inch well is labeled as soil gas
extraction well EW-1. No well log is available for this well
and it is not connected to the SVE system. The well is
screened below the water table and does not appear to be
a soil gas extraction well. The well may be the pilot well for
a SVE test that was done prior to construction of the SVE
system (Maurer 2003).
2. Unknown wells. The three wells are suspected to be OWC-1,
OWC-2, and OWC-3 (from right to left). The wells appear to be
soil gas monitoring wells.
3. MW-08 was not located. The area is overgrown.
4. In 1986 the shaded areas parallel to the railroad tracks
and west of the VES building were excavated to remove
filter cake/soil. The remaining shaded area was excavated
1991-1992 to remove filter cake/soil.
Legend
^ Groundwater Extraction Well
© Groundwater Monitoring Well
® Soil Gas Monitoring Well
® Soil Vapor Extraction Well
CDM Well 12A Superfund Site Figure 2-3
Tacoma, Washington Site Map and Well Locations
-------
CH2M-4
®—a—a
Center St
CH2M-3 •
CH2M-1
CH2M-2
CBW-10
CBW-4
Legend
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
CBW-5.
OHM Well 12A Superfund Site Figure 2-4
Tacoma Washington Groundwater Flow Gradients and Capture Zone Extent
-------
GP-15
Result Depth
(mg/kg) (fbgs)
GP-8
Result Depth
(mg/kg) (fbgs)
0.004 I 1 T~
MW-306
Result Depth
(mg/kg) (fbgs)
GP-3
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
WCSB-2
GP-1
Result Depth
(mg/kg) (fbgs)
WCSB-1
Result Depth
(mg/kg) (fbgs)
0.00003
WCSB-3
GP-7
Result Depth
(mg/kg) (fbgs)
WCSB-4
GP-10
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
MW-305
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
MW-304
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
MW-302
Result Depth
(mg/kg) (fbgs)
GP-13
Result Depth
(mg/kg) (fbgs)
GP-6
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
MW-308
Result Depth
(mg/kg) (fbgs)
Notes:
1) Bolded values indicate result exceeds
Method B modified (PCE=1.7 mg/kg) in
vadose zone.
2) Depth to groundwater in source area
is approximately 33ft bgs. Therefore,
samples collected below 33ft bgs are in
or associated with the saturated zone.
3) Locations with no posted
concentration indicates no data
available.
The soil to groundwater
Method B cleanup level for
the unsaturated zone is
0.0586 mg/kg and the
saturated zone is 0.0029 mg/
kg when the groundwater
MCL (5 ug/L) is used. The
yellow shaded values
indicate results exceed the
unsaturated zone value.
Result
Depth
(mg/kg)
(fbgs)
1.3
10
MW-301
Result Depth
(mg/kg) (fbgs)
GP-2
Result Depth
(mg/kg) (fbgs)
0.002 I ~
Wright Ave
Result Depth
(mg/kg) (fbgs)
GP-19
Kesult
Depth
(mg/kg)
(fbgs)
2 I
2
CDM Well 12A Superfund Site Figure 2-5
Tacoma, Washington Tetrachloroethylene in Soil
-------
Notes:
1) Bolded value indicates result
exceeds Method B modified
(TCE=23 mg/kg) in vadose
zone.
2) Depth to groundwater in
source area is approximately
33ft bgs. Therefore, samples
collected below 33ft bgs are
assumed to be in or associated
with the saturated zone.
DB-001
Result
Depth
(mg/kg)
(fbgs)
0.005
33.25
0.005
58.25
WCSB-1
DB-005
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
0.2
35
0.005 I 33
0.2
40
WCSB-2
GP-15
GP-8
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
0.05
35
0.002
3
0.02 | 11
3.44
40
0.002
7
GP-19
Kesult Depth
(mg/kg) (fbgs)
SB-002
Kesult Depth
(mg/kg) (fbgs)
0.116 |
SB-005
Kesult Depth
(mg/kg) (fbgs)
The yellow shaded values
exceed the soil to
groundwater Method B
cleanup level (0.0243 mg/kg)
for the unsaturated zone
when the MCL (5 mg/L) is
used. The saturated zone
soil to groundwater Method
B cleanup level is 0.0012
mg/kg when the MCL (5 ug/
L) is used.
The soil to groundwater
Method B cleanup level for
the unsaturated zone is
0.0117 mg/kg and the
saturated zone is 0.0006 mg/
kg when the groundwater
clean up level is 2.4 ug/L.
CO
GP-1
Kesult
(mg/kg)
Depth
(fbgs)
50
GP-2
Kesult
0.0006
20
0.077
34
0.79
36
11
38
33
42
100
44
GP-18
Result
Depth
(mg/kg)
(fbgs)
13
2
0.4
4
(mg/kg)
Depth
(fbgs)
0.003
BN-1
Result
Depth
(mg/kg)
(fbgs)
0.048
22
0.072
32
7.8
34
4.5
36
21
40
24
42
B-6
Result
Depth
(mg/kg)
(fbgs)
58
3
55
9
55
11
7
20.5
5.5
26
9.3
30.5
3.4
36.5
GP-3
Result
Depth
(mg/kg)
(fbgs)
24
4
55
4
0.004
16
0.003
23
0.004
29
0.007
31
0.0119
31
MW-306
Result Depth
(mg/kg) (fbgs)
0.01
30
0.0058
33
0.04
34.5
0.021
39
0.0091
45
0.026
80
GP-7
Result
Depth
(mg/kg)
(fbgs)
0.002
5
0.002
7
GP-10
Result
Depth
(mg/kg)
(fbgs)
1.5
3
0.3
5
WCSB-3
Result
Depth
(mg/kg)
(fbgs)
10
35
2
40
BN-7
Result
Depth
(mg/kg)
(fbgs)
0.091
30
0.058
34
0.419
36
0.37
38
23
42
6.99
46
4.9
48
SB-004
Kesult
Depth
(mg/kg)
(fbgs)
0.005
35
MW-301
Result
Depth
(mg/kg)
(fbgs)
0.76
22
0.92
27
0.17
41
101
47.5
53
50
0.047
53
0.021
55
0.046
57
0.059
78
0.055
88
2.1
92
~
MW-308
Result
Depth
(mg/kg)
(fbgs)
0.0047
47
0.16
58.5
0.01
67
0.18
73
0.03
97
0.011
104
0.0029
112
0.013
117.5
0.0071
124.5
0.009
138
/ /
CO
£
' /
/
V)
MW-302
WCSB-4
DB-004
DB-003
BN-4
n l
Kesult Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Deptr
(mg/kg) (fbgs
~| 1
J \l
0.24
25
1000
35
1.4
0.5
0.25
3
0.031
27
n I
66
43
700
40
0.005
5.5
0.005
8
0.072
32
n 1
12
46.5
0.005
8
0.005
13
0.11
34
n I
0.35
50
0.005
13
0.005
18
0.22
36
J I
0.19
59
0.098
18
0.005
20.5
2
38
n I
1.2
66
0.005
23
0.005
25.5
65
40
j \
0.075
78
0.005
28
0.005
33
0.015
96
0.5
33
GP-5
0.047
97.5
Result Depth
(mg/kg) (fbgs)
0.003
6
0.003
8
0.004
10
B-2
Kesult
Depth
(mg/kg)
(fbgs)
0.009
2.5
0.01
12.7
0.22
27.8
24
33.75
11
34.65
0.008
37
0.074
38.8
Kesuit
(mg/kg)
ueptn
(fbgs)
0.006
Uepir
(fbgs)
18
Kesult
(mg/kg)
ueptn
(fbgs)
Kesult
(mg/kg)
0.01
0.002
Depth
(fbgs)
5
~w
Kesult
(mg/kg)
0.008
0.011
0.011
0.006 20.5
&
0.011
27
0.003
0.007
0.016
0.13
0.17
X N
Wright Ave
0.013
0.052
Depth
(fbgs)
2.5
13
BN-6
Result
(mg/kg)
Depth
(fbgs)
3.5 I 10
GP-14
Kesult
(mg/kg)
0.003
0.002
Depth
(fbgs)
20
24
31
34
36
B-3
Result
(mg/kg)
0.99
3.6
17
Depth
(fbgs)
2.5
22.7
28
21
30.8
33
35.6
23
37.6
14
39.5
BN-2
Kesult
(mg/kg)
0.048
0.012
3.7
Depth
(fbgs)
13
22
36
42
38
10.9
40
2.4
42
MW-307
Result
(mg/kg)
0.37
Depth
(fbgs)
43
52.5
62.5
0
BN-5
Result
Depth
(mg/kg)
(fbgs)
0.05
20
0.027
31
0.11
33
0.047
34
0.061
36
0.001
39
MW-304
Result Depth
(mg/kg) (fbgs)
1.5
2
0.053
8
0.0097
14.5
0.012
25
0.019
27
0.012
29.5
0.0042
34.5
0.024
37
0.0083
38
0.004
85
0.0043
120
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 2-6
Trichloroethylene in Soil
-------
Notes:
1) Bolded value indicates result
exceeds Method B modified (cis-1,2-
DCE= 800 mg/kg) in vadose zone. No
exceedances in this figure.
2) Depth to groundwater in source area
is approximately 33ft bgs. Therefore,
samples collected below 33ft bgs are
assumed to be in or associated with the
saturated zone.
3 Locations with no posted
concentrations indicates no data
available.
(mg/kg) (fbgs)
WCSB-2
WCSB-1 •
WCSB-3 •
WCSB-5
WCSB-4
The soil to groundwater
Method B cleanup level for
the unsaturated zone is
0.1570 mg/kg and the
saturated zone is 0.0079 mg/
kg when the groundwater
MCL (70 ug/L) is used. The
yellow shaded values
indicate results exceed the
unsaturated zone value.
MW-302
Result Depth
(mg/kg) (fbgs)
MW-307
Kesult Depth
(mg/kg) (fbgs)
MW-304
Kesult Depth
(mg/kg) (fbgs)
Wright Ave
CDM Well 12A Superfund Site Figure 2-7
Tacoma, Washington Cis-1,2-Dichloroethylene in Soil
-------
Notes:
1) Bolded value indicates result
exceeds Method B modified (trans-1,2-
DCE= 1600 mg/kg) in vadose zone. No
exceedances in this figure.
2) Depth to groundwater in source area
is approximately 33ft bgs. Therefore,
samples collected below 33ft bgs are
assumed to be in or associated with the
saturated zone.
3) Locations with no posted
concentrations indicates no data
available.
MW-306
Kesult Depth
(mg/kg) (fbgs)
WCSB-1
Kesult Depth
(mg/kg) (fbgs)
MW-305
Kesult Depth
(mg/kg) (fbgs)
WCSB-2
Kesult Depth
(mg/kg) (fbgs)
The soil to groundwater
Method B cleanup level for
the unsaturated zone is
2.8871 mg/kg and the
saturated zone is 0.1444 mg/
kg when the groundwater
MCL (1000 ug/L) is used. No
result exceeds the
unsaturated zone.
MW-301
Kesult Depth
(mg/kg) (fbgs)
MW-302
Kesult Depth
(mg/kg) (fbgs)
MW-307
Kesult Depth
(mg/kg) (fbgs)
MW-304
Kesult Depth
(mg/kg) (fbgs)
WCSB-5
Kesult Depth
(mg/kg) (fbgs)
WCSB-4
Kesult Depth
(mg/kg) (fbgs)
WCSB-3
Kesult Depth
(mg/kg) (fbgs)
MW-308
Kesult Depth
(mg/kg) (fbgs)
Wright Ave
CDM Well 12A Superfund Site Figure 2-8
Tacoma, Washington Trans-1,2-Dichloroethylene in Soil
-------
Notes:
1) Bolded value indicates result
exceeds Method B modified
(1,1,2,2-PCA=4.6 mg/kg) in
vadose zone.
2) Depth to groundwater in
source area is approximately
33ft bgs. Therefore, samples
collected below 33ft bgs are
assumed to be in or associated
with the saturated zone.
DB-001
Result
Depth
(mg/kg)
(fbgs)
0.005
33.25
0.005
58.25
WCSB-1
Kesuit
Depth
(mg/kg)
(fbgs)
0.2538
35
0.2538
40
DB-005
Result Depth
(mg/kg) (fbgs)
0.012 I
33
WCSB-2
Result
Depth
(mg/kg)
(fbgs)
0.2544
35
0.2544
40
GP-15
Kesuit
Depth
(mg/kg)
(fbgs)
0.02
3
0.02
7
GP-8
GP-19
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
0.05 | 11
CM
"3"
SB-002
SB-005
Result
(mg/kg)
Depth
(fbgs)
Result Depth
(mg/kg) (fbgs)
0.26 |
33
0.059 | 33
BN-3
nr n
(mg/kg) (fbgs)
0.0007
20
3.7
34
7.5
36
15
38
16
42
30
44
The soil to groundwater
Method B cleanup level for
the unsaturated zone is
0.0002 mg/kg and the
saturated zone is 1.105E-05
mg/kg when the groundwater
RBC (0.067 ug/L) is used.
The yellow shaded values
indicate results exceeds the
unsaturated zone values.
GP-7
Result
Depth
(mg/kg)
(fbgs)
0.024
5
0.04
7
GP-10
Result
Depth
(mg/kg)
(fbgs)
2.5
3
1.5
5
GP-18
Result
Depth
(mg/kg)
(fbgs)
18
2
1.1
4
BN-1
GP-1
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
0.072
22
o
CO
0.072
32
GP-2
7.9
34
Result Depth
(mg/kg) (fbgs)
5.9
36
30
40
0.08 | 4
47
42
B-6
Result Depth
(mg/kg) (fbgs)
16
43
57
19
13
23
8.2
20.5
26
30.5
36.5
GP-3
Result Depth
(mg/kg) (fbgs)
1.29
0.3
0.02
0.06
0.5
0.226
16
23
29
31
31
WCSB-3
Result
(mg/kg)
Depth
(fbgs)
0.2539
0.2539
35
40
BN-7
Result
(mg/kg)
Depth
(fbgs)
U
MW-305
Result
Depth
(mg/kg)
(fbgs)
20
1
0.0038
20
0.097
37
0.82
30
CO
1.1
1.54
3.3
43
19
0.49
34
36
38
42
46
CO
V)
SB-004
Result Depth
(mg/kg) (fbgs)
0.035
35
MW-301
Result
Depth
(mg/kg)
(fbgs)
0.34
22
0.72
27
0.13
41
94
47.5
90
50
0.12
53
0.0063
55
0.0046
57
0.043
78
0.0083
88
0.01
92
MW-302
WCSB-4
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
0.042
25
0.2547
35
49
43
0.2547
40
44
46.5
0.46
50
0.23
59
3.4
66
0.17
78
0.0021
96
0.019
97.5
DB-004
Result Depth
(mg/kg) (fbgs)
DB-003
Result Depth
(mg/kg) (fbgs)
2.5
0.5
1.1
0.047
5.5
0.152
0.055
0.417
13
0.461
0.44
0.717
10.9
13
18
23
28
33
0.024
18
0.005 20.5
0.042 25.5
BN-
Result
4
Depth |
(fbgs)
1.6
3.5
13
25
130
27
32
34
36
AO
38
40
0.005
33
~
MW-308
Result
Depth
(mg/kg)
(fbgs)
0.0032
47
0.004
58.5
0.0021
67
0.0041
73
0.0031
97
0.0029
104
0.0017
112
0.0038
117.5
0.0045
124.5
0.0023
138
GP-5 |
Result
(mg/kg)
Depth I
(fbgs)
0.07
6
0.02
8
0.02
10 |
uepin
(fbgs)
ssuu uepin
(mg/kg) (fbgs)
60 | 36
0.008
0.008
&
0.016
Kesun uepin
(mg/kg) (fbgs)
GP-13
Kesuit ueptn
(mg/kg) (fbgs)
0.2
0.01
14
18
20.5
27
N
Wright Ave
B-4
Kesuit Depth
(mg/kg) (fbgs)
0.011
2.5
0.011
13
0.011
20
0.009
24
0.02
31
0.051
34
0.13
36
0.028
43
0.009 52.5
0.019 62.5
BN-6
Result Depth
(mg/kg) (fbgs)
34 10
GP-14
Result Depth
(mg/kg) (fbgs)
0.06
0.02
B-3
MW-306
Result
Depth
(mg/kg)
(fbgs)
0.01
30
0.0054
33
0.011
34.5
0.01
39
0.02
45
0.0059
80
B-2
Result Depth
(mg/kg) (fbgs)
0.011
2.5
0.001
12.7
1.3
27.8
2.8
33.75
1.3
34.65
0.012
37
0.058
38.8
BN-5
Result Depth
(mg/kg) (fbgs)
0.027
20
0.032
31
0.034
33
0.036
34
0.038
36
0.04
39
MW-304
Result Depth
(mg/kg) (fbgs)
19
2
0.44
8
0.027
14.5
0.015
25
0.0039
27
0.018
29.5
0.013
34.5
0.044
37
0.014
38
0.0036
85
0.0043
120
MW-307
Kesuit Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
Result Depth
(mg/kg) (fbgs)
26
77
180
130
46
9.4
25
2.5
0.072
22.7
0.02
28
4.6
30.8
36
35.6
6.33
37.6
3.5
13
0.05
22
0.0048
56
36
38
40
42
39.5
0
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 2-9
1,1,2,2-Tetrachloroethane in Soil
-------
N
Plan view of TCE in soil
Water table
Horizontal Scale
0 100 200 ft
Vertical Scale for Section: Each
dark gray (and light gray) interval
on well bores represent 10 ft
This figure was prepared using static images saved from an EVS three-dimensional model.
COM
Well 12A Superfund Site
Tacoma, Washington
View northwest at TCE in soil
Upper Aquifer Potentiometric Surface on 5/11/2004
TCE_1985_to_2004 above 1,000 ug/kg
Plume shown is TCE > 1000 ug/kg in soil above and below the water table
Light green unit is semi-confining layer
Figure 2-10
Trichloroethylene in Soil
-------
Filter Cake/Shallow Impacted Soil
GROWADA.COM
N
View northwest at PCA in soil
Plan view of PCA in soil water table
Horizontal Scale
100
200 ft
Vertical Scale for Section: Each
dark gray (and light gray) interval
on well bores represent 10 ft
This figure was prepared using static images exported from an EVS three-dimensional model.
Plume shown is PCA > 1000 ug/kg in soil above and below the water table
Light green unit is semi-confining layer
Upper Aquifer Potentiometric Surface on 5/11/2004
r i mm
COM
Well 12A Superfund Site Figure 2-11
Tacoma, Washington 1,1,2,2-PCA in Soil
-------
CH2M-4®
(52)
Notes:
1) MW-308, a deep well, was
used in contouring.
2) * Data represents highest
values at well (duplicate values).
Center St
CH2M-3
(4.6) •
'KRRF-1
(79)* ICF-50
__(190)
"CH2M-1
1(1100)
CH2M-2
(21)
CBW-10
CBW-1
, (1-8)
CBW-4
CBW-11
(8.5)
CBW-6
(ND) \
vvv*>0
Legend
Trichloroethylene MCL (5 ug/L)
Contour (Dashed where Inferred)
Trichloroethene Concentration Contour
CBW-
CDM Well 12A Superfund Site Figure 2-12
Tacoma, Washington Trichloroethlyene in Groundwater
-------
cvv
Ejrtfc* st
CH2M-4
(ND)
e
CENTER SI
MW-301
(ND)
MW-302
(17) \ EW-4
(2200)1,
TOW-4
(280)
MW-C
(89) N
KRRF-1
(36) v
'WVSS-.1A
—(5*6)'
WCC-1E
(74)
(1100)*
CH2Msfl'
5o0-
-------
cv.'
CH2M-4
(ND)
o
CENTER SI
MW-301
(ND)
MW-302
(ND)
•10
MW-B
CBW-1
(ND)
MW-308
(ND)
MW-306
(ND)
TOW-10
(ND)
WCC-2
(ND)
MW-304
(ND)
MW-305
(ND)
MW-A
(ND)
CH2M-3
(ND)
\WCC-6
(NDL
EW-5 X
\
CH2M-2
.(ND)
S 35TH ST
CBW-11
(ND)
CBW-4
(ND)
S J5TH ST
CBW-6
(ND)
CBW-5
(7.2) " *
TWT-10
(ND)
Well 12A
(ND)
CBW-9
(ND)
Well 9A
(ND)
Legend
Wfells (Concentration of
1,1,2,2-tetrachloroethane
ug/L)
1,1,2,2-Tetrachloroethane
Concentration Contours
Property Lines
• Data represents highest value
at well (duplicate values)
Well 12A
Contours of Upper Aquifer
1,1,2,2- Tetrachloroethane
Concentrations
February/March 2008
A
N
Scale in Feet
Source: Parametrix 2008.
COM Well 12A Superfund Site Figure 2 14
_i_ ... . 1,1,2,2 - Tetrachloroethane in Groundwater
Tacoma, Washington
-------
CH2M-4©
— (ND)
Center St
Wells with detected 1,4-dioxane
concentration at or above 6.1 ug/L
criterion:
In yellow
Above contininq unit
EW-5 MW-302
ICF-2 MW-305
MW-A TOW-10
CH2M-3
(ND) ®
KRRF-1
(ND)
Below confining unit
MW-301 MW-308
MW-304 WCC-1A
MW-307
CH2M-1
(0.67 J)
CH2M-2
(1.3)
CBW-1
(0-5J) ®
CBW-1
) (ND)
CBW-4
(ND)
CBW-11
(ND)
CBW-6
(ND) \
vvv*>0
CBW-2
(NS)
CBW-I
(ND)
F:\Parametrix\Well12A\FFS RemAlts\GIS\Proiects\Figure Z 1 4 Dioxane Results.mxd
Notes:
ND = Not detected
NS = Not sampled
J = Analyte detected but value may not be accurate or precise.
All results are in ug/l (micrograms per liter).
Results are from February/March 2008.
Legend
® Groundwater Extraction Well
® Groundwater Monitoring Well
CDM Well 12A Superfund Site Figure 2-15
Tacoma, Washington 1,4-Dioxane in Groundwater
February/March 2008
-------
6/4/2008
CH2M-4
Notes:
1. ug/L - micrograms per liter
2. mg/L - milligrams per liter
3. mS/cm - milliSiemen per centimeter
4. mV - millivolts
5. NTU - nephelometric turbidity units
6. TCE - Trichloroethylene
7. cDCE - cis-1,2-dichloroethene
8. tDCE - trans-1,2-dichloroethene
9. VC - Vinyl chloride
10. N/A - Not analyzed
11. ND - Not detected
12. TCE, cDCE, tDCE and VC concentrations
from Feb/Mar 2008; other results from June
2008. Only nine wells were sampled in June
2008.
13. Gray shading indicates field parameter.
Parameter
Units
Ethane
6/8/2008
MW-C
Ethene
Parameter
Units
Methane
Ethane
Alkalinity
Ferrous Iron
Ethene
Methane
Nitrate
Alkalinity
Nitrite
Ferrous Iron
Nitrate + Nitrite
Nitrate
Sulfate
Nitrite
6/4/2008
WCC-5
Nitrate + Nitrite
Parameter
Units
Sulfate
Ethane
Ethene
6/5/2008
WCC-6
Parameter Units
Parameter Units
ICF-4
Methane
Parameter
Alkalinity
Ethane
Ferrous Iron
Ethene
Nitrate
Monitoring wells with previous LNAPL results
(in red) include TOW-5, TOW-7, TOW-8,
MW-1, MW-2, MW-3, MW-15, MW-16,
MW-17, MW-18, ICF-3, and ICF-4.
Ferrous Iron
Methane
Ferrous Iron
Nitrite
RH
Conductivity
DO
std units
Alkalinity
Ferrous Iron
std units
Nitrate + Nitrite
mS/cm
Conductivity
DO
mS/cm
Sulfate
mg/L
Celsius
Nitrate
Temperature
Turbidity
ORP
Nitrite
^^^^^^^^olorShadincjJ
-------
\N right Ave
CH2M-2
O
S 35th St
Legend
~ Trichloroethylene Plume
Trichloroethylene MCL (5 ug/L) Contour (Dashed Where Inferred)
~ cis-1,2-Dichloroethene Plume
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
— ¦ — Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
™ ¦ — Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
— Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
OQM Well 12A Superfund Site Figure 2-17
Tacoma Washington Groundwater Contamination and Flow Gradients
-------
FilterCake/Snallow Impacted Soil
GROWADA.COM
e
N
- Shallow soil/filter cake treatment zone
- Deep vadose and upper saturated zone soil on east side of Time Oil Building
Since the extent into the saturated zone is being delineated by soil concentrations,
it is included as a soil treatment zone.
View northwest at PCA in soil
Plan view of PCA in soil water table
Horizontal Scale
100
200 ft
Vertical Scale for Section: Each
dark gray (and light gray) interval
on well bores represent 10 ft
This figure was prepared using static images exported from an EVS three-dimensional model.
Plume shown is PCA > 1000 ug/kg in soil above and below the water table
Light green unit is semi-confining layer
Upper Aquifer Potentiometric Surface on 5/11/2004
Well 12A Superfund Site Figure 3-1
Tacoma, Washington Proposed Treatment Zones in Soil
-------
I I 1Igromada.cgmL
? |u
OS :O»0«M0
r v j i
• —113.
I f!—A
M
i «¦ v 1»'
Wm
ft r!
I 4
Plan view of TCE and cis-1,2-DCE in groundwater
This figure was prepared using static images exported from an EVS three-dimensional model.
CDM
Well 12A Superfund Site
Tacoma, Washington
Horizontal Scale
100 200 ft
a
-Proposed High Concentration Groundwater
Treatment Zone
Vertical Scale for Section; Each Low concentration treatment zone is area outside of
dark gray (and light gray) interval ... . ,.
on well bores represent 10 ft hl9h concentration treatment zone
View northwest at TCE and cis-1,2-DCE in groundwater
Upper Aquifer Potentiometric Surface on 5/11/2004
Groundwater
TCE > 300 ug/L m
cis 12DCE > 300 ug/L
Ground
Water
[ GROMADA.COM I
Groundwater plumes shown in both larger images are cis-1,2-DCE (yellow) and
TCE (green) > 300 ug/l in groundwater. Light green unit is semi-confining layer
Figure 3-2
Proposed Treatment Zones in High Concentration
and Low Concentration Groundwater Plume
-------
Plan view of TCE and cis-1,2-DCE in groundwater (blue) and
1,1,2,2 PCA in soil (green/yellow/red)
RAO Summary of the Four Proposed Treatment Zones
Filter Cake/Shallow Soil
Eliminate the risk of direct contact with filter cake at and near the surface. Eliminating the direct contact risk
will also reduce possible vapor intrusion issues. EPA is addressing vapor intrusion under a separate activity
when targeted soil and groundwater contamination is addressed. Prevent or minimize the migration of
contamination from highly contaminated shallow source areas into the deeper vadose zone to prevent
further degradation of deep soil and groundwater
Deep Vadose Soil and Upper Saturated Soil East of Time Oil Building
Eliminate/minimize the mass of contaminants to reduce the mass flux from this high concentration area
High Concentration Groundwater Zone
Reduce the mass flux by ninety percent (a groundwater remediation level) from the high concentration area
soils/groundwater through a specific plane into the dissolved phase treatment zone. The proposed plane is at
or near the current location ofthe 300 ug/l Isonconcentration for TCE and cis-1,2-DCE.
Low Concentration Groundwater Plume
Reduce contaminant concentrations so that the concentrations at the plume perimeter (defined by
Well 12A, new well CW-1, and new well CW-2) meet MCLs (a groundwater remediation level).
COM
Well 12A Superfurid Site
Tacoma, Washington
This figure was prepared using static images saved from an EVS three-dimensional model.
Horizontal Scale
£>
100 200 ft
Vertical Scale for Section: Each
dark gray (and light gray) interval
on well bores represent 10 ft
- Proposed Treatment Zone Compilation (three zones)
Low concentration groundwater treatment zone (the fourth
zone) is outside of highlighted (in red) compilation
View northwest at TCE and cis-1,2-DCE in groundwater (blue) and
1,1,2,2 PCA in soil (green above water table)
Soil with PCA> 1,000 ug/kg
Groundwater with cis DCE or TCE > 300 ug/L
j G ROM-ADA-COM 1
Water table
Plumes shown are TCE or cis-1,2-DCE > 300 ug/l in groundwater and
1,1,2,2 PCA > 1,000 ug/kg in soil
Figure 3-3
Compilation of the Proposed Treatment Zones
-------
Well List for Flux Monitoring
MW 309*, 310 - Proposed
WCC-3* - Existing
WCC-3B - Proposed
CBW-10 - Existing
CBW-10A* - Proposed
MW 311 *, 312 - Proposed
WCC-6* - Existing
WCC-6B - Proposed
WCC-2* - Existing
WCC-2B - Proposed
All wells to monitor shallow
aquifer. Wells with * are upper
reach of aquifer and unmarked
wells are bottom reach.
\N right Ave
CH2M-2
O
S 35th St
Legend
©
(8)
Wells
Wells to Be Used to Monitor Flux
New Proposed Monitoring Well
Compliance Monitoring Well
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
Trichloroethylene MCL (5 ug/L) Contour (Dashed Where Inferred)
Proposed Flux Measurement Line
cis-1,2-Dichloroethene Plume
Trichloroethylene Plume
C5T cw-1
CH2M-4
o
OQM Well 12A Superfund Site Figure 3-4
Tacoma Washington Groundwater Contamination and Flow Gradients
™ with Flux Measurement Line
-------
6/4/2008
CH2M-4
Notes:
1. ug/L - micrograms per liter
2. mg/L - milligrams per liter
3. mS/cm - milliSiemen per centimeter
4. mV - millivolts
5. NTU - nephelometric turbidity units
6. TCE - Trichloroethylene
7. cDCE - cis-1,2-dichloroethene
8. tDCE - trans-1,2-dichloroethene
9. VC - Vinyl chloride
10. N/A - Not analyzed
11. ND - Not detected
12. TCE, cDCE, tDCE and VC concentrations
from Feb/Mar 2008; other results from June
2008. Only nine wells were sampled in June
2008.
13. Gray shading indicates field parameter.
Well List
MW 309*/310 - Proposed
WCC-3* - Existing
WCC-3B - Proposed
CBW-10 - Existing
CBW-10A* - Proposed
MW 311 *7312 - Proposed
WCC-6* - Existing
WCC-6B - Proposed
WCC-2* - Existing
WCC-2B - Proposed
Parameter
Units
Ethane
6/8/2008
MW-C
Ethene
Parameter
Units
Methane
Ethane
Alkalinity
Ferrous Iron
Ethene
Methane
Nitrate
Alkalinity
Nitrite
Ferrous Iron
Nitrate + Nitrite
Nitrate
Sulfate
Nitrite
6/4/2008
WCC-5
Nitrate + Nitrite
Parameter
Units
Sulfate
Ethane
Ethene
6/5/2008
WCC-6
Parameter Units
Parameter Units
ICF-4
Methane
Parameter
Alkalinity
All wells to monitor shallow
aquifer. Wells with * are upper
reach of aquifer and unmarked
wells are bottom reach.
I i i
Color Shading Key
Ethane
Ferrous Iron
Ethene
Nitrate
Monitoring wells with previous LNAPL results
(in red) include TOW-5, TOW-7, TOW-8,
MW-1, MW-2, MW-3, MW-15, MW-16,
MW-17, MW-18, ICF-3, and ICF-4.
Ferrous Iron
Methane
Ferrous Iron
Nitrite
RH
Conductivity
DO
std units
Alkalinity
Ferrous Iron
std units
Nitrate + Nitrite
mS/cm
Conductivity
DO
mS/cm
Sulfate
mg/L
Celsius
l WCC-2*, 23
Nitrate
Temperature
Turbidity
ORP
Nitrite
Temperature
T urbidity
ORP
Celsius
Nitrate + Nitrite
Value indicates aerobic conditions
Sulfate
Value, or TCE degradation chain,
indicates anaerobic conditions
6/4/2008
CH2M-3
Parameter
Units
Parameter Units TOW-4
Ferrous Iron
mg/L
std units
Methane
Ferrous Iron
Alkalinity
Ferrous Iron
Conductivity
DO
mS/cm
,WCC-6*, 6B
std units
mg/L
Celsius
Conductivity
DO
mS/cm
Nitrate
Temperature
Nitrite
Turbidity
ORP
Temperature
Celsius
Nitrate + Nitrite
Turbidity
Sulfate
6/6/2008
MW-302AVE
Parameter
Units
WRIGH'
Parameter Units
Ferrous Iron
mg/L
std units
Ethane
Ethene
Parameter Units
EW-4
Parameter Units
Conductivity
mS/cm
Methane
Alkalinity
Ferrous Iron
Temperature
Turbidity
ORP
Nitrate
WCC-3*, 3B
CBW-10, 10A*
Nitrite
Parameter Units
Nitrate + Nitrite
Parameter Units
Parameter Units
Sulfate
Parameter Units CH2M-1
Parameter Units
Ferrous Iron
£t!
Conductivity
DO
std units
mS/cm
mg/L
Celsius
6/4/2008
CBW-4
Temperature
Turbidity
Parameter
Units
6/6/2008
MW-308
6/5/2008
CH2M-2
Ethane
Parameter
Units
Parameter
Units
Ethene
Parameter Units
Ethane
Ethane
Methane
Ethene
Ethene
Alkalinity
Ferrous Iron
Methane
Methane
Alkalinity
Alkalinity
Ferrous Iron
Nitrate
Ferrous Iron
Nitrite
Nitrate
Nitrate
Nitrate + Nitrite
CBW-2
Nitrite
Nitrite
Sulfate
CBW-6
Nitrate + Nitrite
Nitrate + Nitrite
Sulfate
Sulfate
CBW-5
WELL 12A
CBW-9
Ferrous Iron
Ferrous Iron
Ferrous Iron
mg/L
std units
std units
Conductivity
DO
std units
Conductivity
DO
mS/cm
Conductivity
DO
mS/cm
mS/cm
mg/L
Celsius
Temperature
T urbidity
ORP
Temperature
Turbidity
ORP
Celsius
Temperature
Celsius
Turbidity
Legend
Aerobic
Anaerobic
~
m
Transitional Anerobic/Aerobic
Monitoring Well
Monitoring Well with
Previous DNAPL Result
Well to Be Used to Monitor Flux
Proposed Flux Measurement Line
Trichloroethylene Contour (ug/L)
cis-1,2-Dichloroethylene Contour (ug/L)
. U II . i i ^—IIU — I i > i—„u
330=
«-*-¦
I
COM Well 12A Superfund Site Figure 3-5
' Tacoma, Washington Intrinsic Bioremediation Parameters
and Flux Measurement Location
-------
Well List for Flux Monitoring
MW 309*, 310 - Proposed
WCC-3* - Existing
WCC-3B - Proposed
CBW-10 - Existing
CBW-10A* - Proposed
MW 311 *, 312 - Proposed
WCC-6* - Existing
WCC-6B - Proposed
WCC-2* - Existing
WCC-2B - Proposed
All wells to monitor shallow
aquifer. Wells with * are upper
reach of aquifer and unmarked
wells are bottom reach.
Arrows on the capture zone line
indicate capture zone extends
upgradient to nearest groundwater
divide.
Legend
o
Wells
®
%
O
Wells to Be Used to Monitor Flux
New Proposed Monitoring Well
Compliance Monitoring Well
•—
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
—
Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
—
Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
IM " ™
Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
Proposed Flux Measurement Line
—
Trichloroethylene MCL (5 ug/L) Contour (Dashed Where Inferred)
~
cis-1,2-Dichloroethene Plume
^ Trichloroethylene Plume
I I
Excavation and Capping Area
I .
In-situ Thermal Remediation
Capping and excavation are identified with
the same symbol to simplify illustrating the
locations. Showing the two alternatives
together does not imply that the alternatives
need to be performed together.
Center St
OVV- I /
J&'
One Compliance Monitoring
Well, Well-12A, is located
960 feet southwest of IM-2.
O CBW-1
/
/
MW-311*, 312 '
/
/
/
/
/
/
/
/
/
/
OQM Well 12A Superfund Site Figure 4-1
Tacoma Washington Excavation, Capping and In-situ Thermal Remediation Alternatives
-------
Well List for Flux Monitoring
MW 309*, 310 - Proposed
WCC-3* - Existing
WCC-3B - Proposed
CBW-10 - Existing
CBW-10A* - Proposed
MW 311 *, 312 - Proposed
WCC-6* - Existing
WCC-6B - Proposed
WCC-2* - Existing
WCC-2B - Proposed
All wells to monitor shallow
aquifer. Wells with * are upper
reach of aquifer and unmarked
wells are bottom reach.
Legend
o
Wells
®
Wells to Be Used to Monitor Flux
•
Injection Wells
m
o
New Proposed Monitoring Well
Compliance_Monitoring_Well
•—
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
—
Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
—
Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
—
Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
Trichloroethylene MCL (5 ug/L) Contour (Dashed Where Inferred)
Proposed Flux Measurement Line
~
cis-1,2-Dichloroethene Plume
^ Trichloroethylene Plume
I I
Excavation and Capping Area
I .
In-situ Thermal Remediation
Center St
CW-1, '
Arrows on the capture zone line
indicate capture zone extends
upgradient to nearest groundwater
divide.
One Compliance Monitoring
Well, Well-12A, is located
960 feet southwest of IM-2.
o CBW-1
CH2M-2
O
/
/
/ J I I I { I
/ CW-2 (®)
/
/
MW-311 *, 312 /
/
/
/
/
/
/
/
/
/
/
OQM Well 12A Superfund Site Figure 4-2
Tacoma Washington Enhanced Anaerobic Bioremediation Alternative
-------
Well List for Flux Monitoring
MW 309*, 310 - Proposed
WCC-3* - Existing
WCC-3B - Proposed
CBW-10 - Existing
CBW-10A* - Proposed
MW 311 *, 312 - Proposed
WCC-6* - Existing
WCC-6B - Proposed
WCC-2* - Existing
WCC-2B - Proposed
All wells to monitor shallow
aquifer. Wells with * are upper
reach of aquifer and unmarked
wells are bottom reach.
Arrows on the capture zone line
indicate capture zone extends
upgradient to nearest groundwater
divide.
Legend
o
Wells
®
Wells to Be Used to Monitor Flux
•
Injection Wells
o
Soil Vapor Extraction Wells
¦
Q
Air Sparging Wells
New Proposed Monitoring Well
Compliance Monitoring Well
•—
Groundwater Gradient
Groundwater Elevation Contours (Dashed Where Inferred)
Modeled Capture Zone, Simulated for May 11, 2004 (USEPA2005)
—
Capture Zone Based on Groundwater Contours, May 11, 2004 (URS 2005)
—
Capture Zone Based on Groundwater Contours, December 20, 2004 (URS 2005)
—
Capture Zone Based on Groundwater Contours, February 23, 2005 (URS 2005)
Trichloroethylene MCL (5 ug/L) Contour (Dashed Where Inferred)
Proposed Flux Measurement Line
~
cis-1,2-Dichloroethene Plume
^ Trichloroethylene Plume
| ] Excavation/Capping
L _ 1
In-situ Thermal Remediation
Angled Wells to
I
Center St i
i
CW-1 '
One Compliance Monitoring
Well, Well-12A, is located
960 feet southwest of IM-2.
O CBW-1
/
/
MW-311*, 312 '
/
/
/
/
/
/
/
/
/
/
OQM Well 12A Superfund Site Figure 4-3
Tacoma Washington Air Sparging and Soil Vapor Extraction Alternative
' with Enhanced Bioremediation
-------
Conceptual Schedule of Proposed Well 12A Remedial Actions
I Finalization of Remedial Actbn Work
Plan and Initiation of Field Work
Performance Groundwater Sampling
, (PCS)
^xcavation |
PGS
~IPGS ~IPGS ~IPGS ~!
~IPGS
~IPGS
~IPGS
PGS
~I
~IPGS
~IPGS
~IPGS
ERH
EAB
~ GETS Shut Down
r——f——f——
M-01! J-01 A-01 0-01 D-01 F-02 A-02 J-02 A-
-02 O-02 D-Q2 F-03 A-03 J-03 A-03 0-03 D-03 F-04 A-04 J-04 A-04 Q-04 D-04 F-05 A-05 J-05 A-05 O-05 D-05 F-C® A-06 J-06 A-06 0-06 D-06 J-07 M-07
^—I
Flux Measurement 18 months post-EAB
~—I
Baseline Flux Measurement with GETS
on
«—|Flux Measurement 1 Post-GETS
Shutdown
4—I Flux Measurement 2 Post-GETS
Shutdown
~—I
Flux Measurement 3 Post-GETS
Shutdown
NOTES:
-01, 02 implies Year 1, Year 2, etc.
-Baseline flux monitoring at initiation of activities
- Monthly GW performance monitoring for the six
months of ERH
-PGS quarterly for EAB in YR01 and biannual
thereafter
The State would be taking over the site after the GETS is
turned off and
•90% flux reduction groundwater remediation level is met
•MCLs are met at the compliance wells 12A, new well CW1,
and new well CW2
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 5-1
Conceptual Schedule of Proposed
Well 12A Remedial Actions
-------
Appendix A
Contaminant Source Strength and Timing
and Sensitivity Analysis Memorandum
-------
CDM
893 Old Eogla School Raid. Suit* 400
WiyiW, PMrttylvtitii 19087
Id: 610 !S3-0
-------
Draft Technical Memorandum
Contaminant Source Strength and Timing
and Sensitivity Analysis
Purpose
The objectives of this contaminant transport groundwater modeling task are to:
¦ Estimate the contaminant source timing and strength
¦ Analyze the sensitivity of the model to source strength
This memorandum documents the modeling activities that were completed for the
source timing and strength evaluation and the sensitivity analysis. After the model is
accepted, it may be used as a tool to evaluate remedial alternatives. For example, if the
contaminant (e.g., TCE) source is removed and groundwater concentrations are reduced
by ninety percent, what will be fate of the plume. The alternative evaluation simulations
may be run in the future and a second memorandum will be prepared to document the
simulation results.
Conceptual Model
A conceptual model that included steady-state numerical models of the Well 12A
hydrogeologic system was presented as part of the Draft Final Field Investigation and
Capture Zone Analysis Report Commencement Bay, South Tacoma Channel/Well 12A
Superfund Site Tacoma, Washington (URS, 2005). The conceptual model presented the
modeler's understanding of the occurrence and movement of groundwater in the area of
interest and is based on regional data, site-specific data and general hydrogeologic
knowledge. The Draft Final Field Investigation and Capture Zone Analysis Report did
not address site contamination or contaminant transport.
Site Contamination
Source timing and strength were estimated based on aquifer solute transport parameters
and current TCE distributions in groundwater. Using these values, the TCE release
pattern using current mass and distribution of TCE was estimated.
Aquifer Transport Properties
TCE is adsorbed on sites within the aquifer matrix, limiting its mobility in groundwater.
This adsorption may occur on sites such as natural organic carbon coatings on aquifer
materials, but may also occur to a lesser degree on inorganic surfaces such as clay or iron
minerals. The chemical characteristic that defines the degree to which the chemical are
adsorbed is the organic carbon partitioning coefficient (Koc), which is reported in
numerous sources for the chemicals of interest. This coefficient defines the degree to
which a chemical will partition onto the solid phase adsorption sites. At concentrations
observed at the site, this process is assumed to be linear, instantaneous and reversible.
A bulk measure of the adsorption capacity of the aquifer material may be estimated
-------
using the Koc and the organic carbon concentration in the soil. This term is described as
the soil - water partitioning coefficient (Kd). Kd may be estimated by multiplying the
fraction of organic carbon present in the soil by the Koc value for the chemical of
interest.
Once Kd has been estimated for the chemicals of interest and the aquifer material at the
site, the velocity of the contaminants may be estimated. These equilibrium sorption
processes have the effect of slowing movement of contaminants relative to the
groundwater velocity. The ratio of the velocity of the groundwater to that of the
contaminant front is referred to as the retardation factor, R. A value of 1 for R indicates
7-) 1 Kd*Density
TotalPoroaty
the contaminant moves at the same velocity as groundwater. The R value can be
estimated from the following equation:
Where:
R - Ratio of average groundwater velocity to average contaminant velocity
Kd - soil water partitioning coefficient
Density - dry bulk density of aquifer soil
Total Porosity - total porosity of aquifer material
Values for the aquifer parameters were determined from laboratory analysis of aquifer
materials collected during field activities for the Draft Final Field Investigation and
Capture Zone Analysis Report (URS, 2005). The Koc value for TCE was chosen from a
table entitled Physical Chemical Data for Volatile Organic Compounds posted on the
EPA Region 9 website.
rb= 1.88 gram/milliliter
ne = 0.21
Koc = 170 millilter/gram (Foc = 0.0017)
Incorporating these values, a retardation factor of 3.5 was calculated. This high capacity
for adsorption of TCE on the aquifer matrix will result in slowed flushing of the aquifer,
following elimination of the source of additional mass.
In addition, TCE may readily degrade under the proper biogeochemical conditions in
aquifers. A reasonable half-life for TCE in aerobic groundwater is 7 years and would
tend to decrease the effective TCE velocity in groundwater.
2
-------
Lastly, the effect of dispersion spreads contaminant mass beyond the region it would
normally occupy due to advection alone. Dispersion occurs in three directions
(longitudinal, transverse and vertical). Longitudinal dispersivity is the largest and
transverse and vertical are commonly considered to be one and two orders of magnitude
lower, respectively. Longitudinal dispesivity is defined as
Dispersivity = 0.83 (log (plume length))2414
where length is in meters (Xu and Eckstein 1995).
Therefore, using a plume length of 2,640 ft (805 m), longitudinal dispersivity is 35.8 ft.
Transverse and vertical dispersivity is suggested to be 3.6 and 0.1 ft, respectively.
Groundwater Travel Time
Travel times were estimated for groundwater moving from the former Time Oil site to
Well 12A. The contaminant release date was estimated by dividing the travel distance
by the travel time according to the following relationship:
Time = Distance/Vp0re
Groundwater velocity was determined by the following relationship:
V pore = Ki/ ne
where
K = hydraulic conductivity
i = hydraulic gradient
ne = effective porosity
¦ Based on water elevations collected when Well 12A was pumping and the GETS
was not operating (July 9,1985), the groundwater gradient from source to sink
(Well 12A) is 0.0023.
¦ Numeric groundwater flow modeling indicates that aquifer materials located
between the source area and Well 12A have an average hydraulic conductivity of
550 feet/ day.
¦ The effective porosity of site materials was determined as part of laboratory
analyses conducted on aquifer samples collected from the former Time Oil Site
during field activities conducted as part of the Capture Zone Analysis Report
(URS 2005). The average effective porosity for aquifer materials is approximately
0.21.
3
-------
Incorporating these values, Vp0re = 6.0 feet/day. This rate is the average velocity of a
conservative tracer traveling from the former Time Oil site to Well 12A. Well 12A
operates, on average, 90 days per year. Therefore, this flow scenario applies, on average,
90 days per year. As a result, source area groundwater travels approximately 540 ft
toward Well 12A each year.
However, the transport of TCE is retarded by interaction with aquifer solids. The
retardation factor (Rf) affects travel velocity according to the following relationship:
Vice = (Vpore)(Rf)
Vtce = (6.0 feet/ day)/3.5
Vtce = 1.7 feet/ day or 154 feet/year
The distance from the presumed source area within the former Time Oil site and well
12A is approximately 2,600 feet. Using these values yields:
Time = Distance/VicE
Time = 2,640 feet/ (154 feet/year)
Time = 17 years
This travel time assumes that a contaminant particle travels toward Well 12A when the
well is operating and when it is shut off, the contaminant stops at its current location
and does not migrate from that position. When Well 12A is re-started, then the particle
is remobilized and continues to travel toward the pumping well. This stopping and
starting continues until the particle is captured by the well. In reality, the particle does
not stop moving when Well 12A is shut off. Rather, the particle moves eastward (away
from Well 12A) under the ambient gradient when the well is shut down. If the well
operates a limited amount of time, then intuitively, the particle would not reach the
pumping well. Rather, the particle would have a significant amount of time to travel
eastward beyond the Well 12A influence and the limited time of pumping would not be
sufficient to overcome the natural prevailing gradient.
Released TCE Mass
This travel time of 17 years appears to coincide with the time between when Time Oil
Company acquired the majority of the property (1964) until when Well 12A
contamination was first identified (1981).
The total TCE mass released includes all mass released from the former Time Oil site
from initial release, until February 2008 (date of most recent groundwater sampling).
According to site records, TCE was detected at well 12A in July, 1981. Using the
transport time of approximately 17 years, the suspected release of TCE began around
1964. The model was constructed to simulate a release date of January 1963 to allow for
monitoring early arrival times.
Calculating the total released mass was accomplished by choosing a reasonable decay
constant for TCE and back-calculating from the present estimated TCE mass, as
calculated using Environmental Visualization System (EVS) software.
4
-------
¦ Using the 2008 groundwater data, the EVS software calculates a mass of 60
kilograms of TCE remaining in the portion of the groundwater plume containing
TCE concentrations greater than 10 ug/L TCE.
¦ A half-life of seven years is typical for TCE dissolved in aerobic aquifers.
¦ Since the estimated release date of 1963, approximately 6.5 half-lives have
elapsed.
¦ Using a half-life of seven years, an original mass of 5,500 kg of TCE would
account for a remaining mass of 60 kg.
¦ 5,500 kg of TCE corresponds to approximately 21 drums of TCE.
This back calculation provides an approximation of the mass that may have entered into
the system. However, it is recognized that the estimates may differ since it does not take
into account variables such as a changing mass input over time (e.g., 500 kg of TCE
entered the system in 1965 and 500 kg of TCE entered the system in 1975).
Numerical Model Source Term
To design the source term, the mass flux through the source was estimated according to
the source geometry, the source area flow velocity, and source concentration.
¦ The EVS visualizations show the portion of the 2008 TCE plume with
concentrations greater than 1000 ug/L to be approximately 220 feet in width
(perpendicular to groundwater flow).
¦ The location of the source was simulated to extend 220 feet from the area of
excavated soil eastward across the former Time Oil building.
¦ Two hydraulic zones split the source area in approximately equal portions. One
zone is 400 feet/ day and the other is 40 feet/ day. For the source area mass flux
calculation, the lower hydraulic gradient was considered to predominate. This
conclusion was based on the observed GETS well yields, which are quite low. As
a result a conductivity of 40 feet/ day was used for the source area. Groundwater
velocity was determined by the following relationship:
V pore = Ki/ ne
Vpore = (100 feet/day)(0.0006)/0.21
Vpore = 0.32 feet/day
¦ The saturated cross sectional area of the source is 220 feet in width and 70 feet in
thickness. The resulting cross-sectional area is 15,400 square feet. The discharge
through the source term equals the cross sectional area multiplied by the pore
water velocity:
5
-------
Q = (source cross section) (Vp0re)
The resulting discharge through the source is 5.02 X 107 L/year
¦ To match the estimated release history, the source term for the model provided
approximately 5,100kg of TCE throughout the model's 45 year simulation. A
decaying source term was used. The release starts in January 1963 at a
concentration of 2,500 ug/L. The source concentration drops to 1,500 ug/L in
November, 1997, corresponding to the cessation of soil vapor extraction.
¦ The total mass released equals the product of the discharge through the source
term, the flow duration, and the source concentration.
TCE mass = (Q)(source duration)(source concentration)
TCE mass = (5.02 X 107 liter/year)(35 yr)(2,500 ug/L) = 4393 kg
TCE mass = (5.02 X 107 liter/year)(10 yr)(l,500 ug/L) = 753 kg
TCE mass = 5,146 kg
Transient Simulations
The transient model was based on the steady-state model that was calibrated to match
conditions in July 9,1985, when Well 12A was pumping and the GETS was not
pumping. Aquifer storage parameters were added to the steady state model based on
the results of a single long-term aquifer test performed in the upper aquifer. These
storage values were estimated by matching the simulated response of four monitoring
wells (CH2M-1, IDF-5S, MW-305, and WCC-1A) to the measured aquifer responses at
these wells during cessation of the GETS in February 2008. A single storage value was
used for the entire site, as it was assumed that the lower aquifer had the same storage
value. The best match was achieved using a specific yield (Sy) of 0.1. Figure 1 displays
the matches of measured and simulated data using Sy of 0.1.
Pumping Conditions
The transient simulation covers changing pumping conditions over 45 years. The details
of which are as follows:
¦ Beginning in 1963, Well 12A is pumping at 4,000 gallons per minute (gpm) for 90
days per year. Well 12A does not pump for the remaining 275 days. The cycle is
repeated for the remainder of the simulation (until 2008).
¦ Beginning in 1988, the GETS system (approximated by one boundary condition)
begins pumping continuously at 38 gallons per minute until 1995.
¦ Beginning in 1995, the GETS system (approximated by one boundary condition)
begins pumping at 75 gallons per minute. This pumping continued for the
remainder of the simulation.
¦ Beginning in 1963, Tacoma Wells 2B, 9A, 4A, and 6A/11A are pumping year-
round, at a single discharge rate. The discharge rate is one half of each well's
6
-------
measured discharge rate as measured on July 9,1985. Drawdown induced by
steady-state pumping of these wells at a reduced discharge rate was found to be
indistinguishable from pumping these wells at a higher rate, for 90 days per year.
The steady-state pumping rates included in the model were 644 gpm for Well 2B,
295 gpm for Well 9A, 56 gpm for well 4A, and 4,220 gpm for well 6A/ 11A.
Individual Simulations
Attempts to match simulated TCE distribution with measured TCE distribution were
not successful using realistic Well 12A pumping rates and duration. In an attempt to
learn as much as possible from the transient simulations, various scenarios were
simulated. Both advective travel times and simulated solute transport are presented.
The advective travel times provide a visualization of groundwater flow; retardation,
dispersion and decay are not included in advective transport.
¦ Figure 2 shows particle tracks emanating from the site and from a point to the
east of the site. The simulation shows the effects of 45 years of Well 12A
pumping at 4,000 gpm, 90 days per year. No particles travel to Well 12A; the
eastward ambient gradient prevails. Therefore, the sink values (both time and
strength) that are located southeastward of the Time Oil site are not sufficient to
support the transport of contaminants to Well 12A, or another site feature has
not been identified and is not incorporated into the model. For example,
perhaps discrete zones, which have not been identified by site investigation, of
high hydraulic conductivity are present that provide a pathway from the site to
Well 12A.
¦ A second simulation was run to estimate the pumping time needed to begin to
achieve capture. Figure 3 presents the results of simulation two. The simulation
shows the effects of 45 years of Well 12A pumping at 4,000 gpm, 182.5 days per
year. Even under this unrealistic pumping scenario, only particles far to the east
of the former Time Oil site are captured by Well 12A.
¦ As a third metric, a third simulation was run to evaluate the effects of 45 years of
Well 12A pumping at 4000 gallons per day, 305 days per year. Under this
unrealistic pumping scenario, particles from the former Time Oil site are
captured by Well 12A.
¦ Although advective transport evaluations indicated prevailing gradients to the
east TCE transport was considered to evaluate the effects of transport properties.
Figure 5 shows the TCE distribution resulting from a transient TCE source term
located at the former Time Oil site. The simulation shows the effects of 45 years
of Well 12A pumping at 4000 gallons per day, 90 days per year. No TCE goes to
Well 12A.
¦ Figure 6 shows the TCE distribution resulting from a transient TCE source term
located at the former Time Oil site. The simulation shows the effects of 45 years
of Well 12A pumping at 4000 gallons per day, 305 days per year.
7
-------
Conclusions
Several conclusions, which are presented as finding and recommendations, were
developed from this modeling task.
Findings
¦ When Well 12A is operating, groundwater velocity to the well is estimated to be
6 ft/day. The retarded velocity for TCE is estimated to be 1.7 ft/day.
¦ Travel times suggest the source to start in the early to mid-1960s, which is when
the Time Oil Company took control of a majority of the property.
¦ Well 12A operates approximately 3 months/year. When the well is operating,
the hydraulic gradient at the site is to the southeast toward the sink. When the
well is not operating, the ambient gradient is to the east.
¦ Estimates suggest that the ambient gradient prevails and dissolved contaminants
would not migrate from the Time Oil property to Well 12A under current known
conditions. However, if an unidentified feature exists that creates a pathway
from the property to the well, then contaminants will migrate as seen in well
concentrations.
Recommendations
¦ Contact the City of Tacoma and allow them to verify the extraction well
pumping rates
¦ Research if regional maps have been prepared that maps the potentiometric
surface under the pumping conditions of the Tacoma wells and determine if a
prevailing gradient is toward Well 12A due to pumping or if the eastward
ambient conditions prevail
¦ If extraction well rates are verified and/ or regional data suggest a prevailing
gradient eastward, then the analytical information in this memorandum shall be
used to assist in evaluating remedial alternatives.
8
-------
References
URS Inc., 2005. Draft Final Field Investigation and Capture Zone Analysis Report
Commencement Bay, South Tacoma Channel/Well 12A Superfund Site Tacoma, Washington.
Report prepared for EPA Region Region 10. September.
U.S. Environemntal Protection Agency Region 9. Region 9 PRGs 2004 Table:
TRICHLORETHYLENE. Website
http: / / www.epa.gov/region09/waste/sfund/prg/files/04pr gtable.pdf Accessed
lune 2008.
http:/ / www.epa.eov/ATHENS/learn2model/part-two/onsite/lonedisp.htm
-------
DO*l
\
X
/
1
1
1
—
m 9 «D< «0t «&• 4010
HWXB
\
\
*
\
\
V
1
1
I
/
1
1
»
¦¦¦—-—. _
—¦—-
w»s •»> mi W( *33 • «na
CDM
1
y
L
i X
t
ii
\
\
\
\
>
\
1
¦ —
-—
-
B95 <061 *»> «»l «»e «no
it—
>«au
IV
i \
i
\
i
i
\
\
"
\
~
/
/
¦Vfc
\
M H 1001 Xa I «&t »»B 4010
Time in days
Drawdown in feet
Well 12A Superfund Site
Tacoma, Washington
Figure 1
Simulate and Measured Hydrographs of
Monitoring Wells after Cessation of GETS in
February 2008
-------
Well 12A pumping for 45 years at 90 days per year
Arrow interval represents one year travel time
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 2
Simulation 1
Estimated Path lines
-------
Well 12A pumping for 45 years at 182 days per year
Arrow interval represents one year travel time
Figure 3
Well 12A Superfund Site
Simulation 2
Tacoma, Washington
Estimated Path lines
-------
Well 12A pumping for 45 years at 305 days per year
Arrow interval represents one year travel time
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 4
Simulation 3
Estimated Path lines
-------
CDM
Well 12A pumping for 45 years at 305 days per year
Concentrations are ICE from 10 to 1,500 ug/l
Well 12A Superfund Site
Tacoma, Washington
Figure 5
Simulation 4
Estimated Path lines
-------
Well 12A pumping for 45 years at 305 days per year
Concentrations are ICE from 10 to 1,500 ug/l
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 6
Simulation 5
Estimated Path lines
-------
Appendix B
Monitored Natural Attenuation Evaluation
Memorandum
-------
COM
883 Old Eagla School fioad, SulM 408
Wiyna, P»no»y)v«ni« 18087
t«: 810 293-0460
'«*: 61OJ03-1#M
August 4, 2008
Kira Lynch
US EPA Region 10
Office of Environmental Cleanup (ECL-113)
1200 Sixth Avenue, Suite 900
Seattle WA 98101
Subject: Well 12A Focused Feasibility Study Monitored Natural Attenuation Evaluation
Memorandum
Dear Ms. Lynch:
Please find enclosed the Draft Well 12A Focused Feasibility Study Monitored Natural
Attenuation Evaluation Memorandum. This draft memorandum is being submitted to
you as a partial fulfillment of the reporting requirements for this assignment.
If you have any questions, call me at (610) 293-0450.
Project Manager
CDM Federal Programs Corporation
-------
Revised Draft
Well 12A Monitored Natural Attenuation Evaluation Memorandum
July 29, 2008
Groundwater samples were collected on June 4, 5 and 6, 2008 from wells at the Well 12A
Superfund site in Tacoma, Washington and analyzed for monitored natural attenuation
(MNA) parameters, enzyme activity, and microbial DNA. The purpose of the event was
to collect data to determine where biological degradation is occurring and characterize
the areas and degree of activity. The monitored natural attenuation parameters are
reported in this memorandum and the enzyme activity and DNA analyses are also
summarized. The enzyme activity probe (EAP) analyses and molecular assays are
detailed in Enzyme Activity Probe Assessment of Groundwater: Parametrix/CDM by North
Wind, Inc. and dated July 11, 2008. The groundwater samples were collected in
accordance with the Quality Assurance Project Plan Addendum Monitored Natural
Attenuation Supplemental Sampling Event dated May 30, 2008 and prepared by CDM.
The data reported for the analyses is presented in attached Table 1 and Figure 1. In
general, the information in the figure is similar to the data in the table. The figure
illustrates the sampling point locations relative to each other and the source area.
Volatile organic compound (VOC) concentrations that can be used to assess biological
degradation are also presented in the table and figure. The VOC data are for samples
collected in February/March 2008. No samples for VOC analyses were collected from
wells during the June 2008 MNA event.
Several observations can be made on the biological degradation conditions on inspection
of the data. General observations and the groupings of wells (aerobic, anaerobic and
transitional conditions) are identified below.
General Observations
¦ Peripheral wells surrounding the Time Oil property show aerobic conditions,
with TCE present in low concentrations
¦ Wells within the source area tend to be anaerobic, with a full range of TCE
degradation products (cis & trans 1,2-DCE, Vinyl Chloride, and gases where
measured)
Wells with aerobic conditions (clockwise from north):
¦ CH2M-4 - NO3 3.54 mg-N/1, ORP 247, TCE primary contaminant (this location
may be in an area of a separate VOC source)
¦ CH2M-3 - NO3 4.62 mg-N/1, ORP 81 (unusually low), TCE primary contaminant
¦ WCC-6 - NO3 3.38 mg-N/1, ORP 192, TCE primary contaminant
¦ CBW-4 - NO3 1.87 mg-N/1, ORP 231, TCE primary contaminant
¦ WCC-5 - NO3 2.08 mg-N/1, ORP 226, with TCE, cis and trans-1, 2DCE, and VC
¦ MW-C - NO3 2.89 g-N/1, ORP 266, with TCE, cis & trans-1, 2DCE, and VC
¦ Additional aerobic condition observations for the aforementioned six wells
1
-------
o CH2M-4, CH2M-3, WCC-5, and CBW-4 - EAP analyses show significant
activity of aerobic cometabolic microorganism populations that may be
contributing to the attenuation of TCE.
o CH2M-4, CH2M-3, WCC-6, and CBW-4 - located at distal locations from
the Time Oil property, and contain no TCE degradation products. These
well conditions are likely indicative of the aerobic conditions present in
the regional aquifer,
o WCC-5 and MW-C - located west of the Time Oil property. The NO3 and
ORP values are indicative of aerobic conditions, but the presence of TCE
degradation products that would normally readily degrade under aerobic
conditions indicate that these wells are in a transition state. Alternatively,
the wells may be close enough to a continuing source so that the
migrating degradation products are continually replenished.
Transition well:
¦ CH2M-2 - Southeast of Time Oil, has lower NO3 (0.771 mg-N/1), and only a
small amount of cis-1, 2DCE (1.5 ug/1), but elevated ORP of 228.
Wells with anaerobic conditions:
¦ MW-302 - North end of Fife Street, southeast of the VES building, has (average
of duplicate samples) low NO3 concentrations (<0.1 mg-N/1), elevated Ferrous++
ion (2.405 mg/1), the lowest dissolved oxygen (2.95 mg/1) of any of the wells
sampled, low concentrations of ethene and ethane, elevated concentrations of
methane (230 ug/1), with TCE, cis and trans-1, 2DCE, and VC. The presence of
SO4 (22.15 mg/1) indicates that conditions are not uniformly methanogenic.
¦ MW-308 - Southwest of the site, below the semi-confining unit, has low NO3
concentrations (0.011 mg-N/1), very low (J-value) concentrations of ethene and
ethane, 14 ug/1 of methane, with TCE, cis and trans-1, 2DCE, and VC.
¦ EW-4, EW-5, ICF-5D - Moderate concentrations of TCE, high concentrations of
cis and trans-1, 2DCE, VC, and PCA. Concentrations of cis-1, 2DCE are 10 to 20
times TCE, indicating significant reductive dechlorination of TCE has occurred.
In EW-4 and EW-5, concentrations of trans 1, 2-DCE are 68% of cis-1,2DCE,
which is an unusually high ratio (the concentrations of cis-1,2DCE are usually
about 30 times trans-l,2DCE). This ratio could be caused by site bacterial cultures
that produce a higher concentration of trans-1,2DCE. Alternatively, cis-1,2DCE is
more readily degraded to VC, and the higher trans-1,2DCE concentrations may
indicate that there once were much higher concentrations of TCE that had
degraded to cis-1,2DCE, VC, and ethene/ethane, and that concentrations of the
more recalcitrant trans-1,2DCE gradually accumulated over time.
¦ EW-3, EW-2, EW-1 - Moderate concentrations of TCE, equal to or approximately
three times cis-1, 2DCE. Reductive dechlorination has occurred, but not to the
same degree as in EW-4 or EW-5. In all three wells, trans-1,2DCE concentrations
are approximately 50% of cis-1,2DCE.
¦ ICF-2 - High concentrations of TCE (1300), with slightly lower concentrations of
cis-1, 2DCE (1100). Concentrations of trans-1,2DCE are only 33% of cis-1,2DCE.
These ratios may indicate that dechlorination has been not been as strong in this
well, with TCE not degrading to the same extent as in other wells.
2
-------
¦ CH2M-1 - High concentrations of TCE (1100 ug/1), with concentrations of cis-
1,2DCE (210) that are 19% of TCE.
¦ ICF-4 - Low concentrations of TCE (50 ug/1), slightly higher concentrations of cis
1, 2-DCE (69 ug/1), trans-l,2DCE (34 ug/1) at half of the cis-1,2DCE
concentration, and higher concentrations of VC (95 ug/1) may indicate ongoing
reductive dechlorination.
Conclusion
The data indicate that significant reductive dechlorination is or has been ongoing at the
Well 12A site, and therefore, the site is not biologically limited. The lack of strongly
reducing conditions indicate that there is currently limited electron donor remaining to
sustain dechlorination. Current reducing conditions may be due to endogenous decay,
where current organisms are stimulated by the dying biomass of previous activity.
The MNA evaluation can be used to guide the development of objectives for a remedial
action and the formulation of a plume management strategy. Currently, the data
suggest the following approach is appropriate
¦ Target destruction of contaminant mass in the source areas - emphasize
reduction of TCE and PCE to below regulatory criteria. Could be accomplished
by targeting source areas (lenses and aqueous phase) by introducing electron
donor, or targeted application of thermal remediation
¦ Reduce mass flux migrating outside of source area, especially TCE and PCE. Any
cis 1, 2 DCE or VC that migrates from anaerobic zones to aerobic zones should
quickly degrade
¦ Monitor MNA of TCE by cometabolic degradation in the aerobic zones on the
periphery of the primary plumes
This approach will be evaluated against other site data (e.g., contaminant movement) to
develop remedial action objectives and a comprehensive plume management strategy.
3
-------
:\Parametrix\Well12A\FFS RemAlts\GIS\June 2008 MNA and VOC Results rev.mxd
6/4/2008
CH2M-4
Parameter
Units
Ethane
6/8/2008
MW-C
Ethene
Parameter
Units
Methane
Ethane
Alkalinity
Ferrous Iron
Ethene
Methane
Nitrate
Alkalinity
Nitrite
Ferrous Iron
Nitrate + Nitrite
Nitrate
Sulfate
Nitrite
6/4/2008
WCC-5
Nitrate + Nitrite
Parameter
Units
Sulfate
Ethane
Ethene
6/5/2008
WCC-6
Parameter Units
Parameter Units
ICF-4
Methane
Parameter
Alkalinity
Ethane
Ferrous Iron
Ethene
Nitrate
Ferrous Iron
Methane
Ferrous Iron
Nitrite
Ed
Conductivity
DO
std units
Alkalinity
Ferrous Iron
std units
Nitrate + Nitrite
mS/cm
Conductivity
DO
mS/cm
Sulfate
mg/L
Celsius
Nitrate
Temperature
Turbidity
ORP
Nitrite
^^^^^^^^olorShadincjJ
-------
Table 1
Well 12A VOC and MNA Groundwater Data
Field Parameters
Well ID
Land
Surface
Elevation
(ft)
Sample
Collection
depth
(ft)
Sample
Collection
Elevation (ft)
PCE (ug/L)
TCE
(ug/L)
cDCE
(ug/L)
tDCE
(ug/L)
1,1DCE
(ug/L)
VC
(ug/L)
PCA
(ug/L)
Total
Chlorinateds
(ug/L)
CI #(1)
1,4-d ioxane
(ug/L)
Previous
LNAPL
Ethane
(ug/L)
Ethene
(ug/L)
Methane
(ug/L)
Alkalinity
(mg/L
CaC03)
Fe++
(mg/L)
N03
(mg-/L)
N02
(mg-/L)
N02+N03
(mg-/L)
S04
(mg/L)
DOC
(mg/L)
Fe ++
(mg/L)
pH
(std
units)
Conduct
(mS/cm)
DO
(mg/L)
ORP
(mV)
Temperature
(Celsius)
Turbidity
(NTU)
DNA
EAP
PA
(Cells/mL)
3HPA
(Cells/mL)
CINN
(Cells/mL)
EW-1
257.01
90.51
166.5
1.9
73
24
14
1 u
2.7
3.3
119.9
2.53
0.6
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
EW-2
255.73
84.23
171.5
9.7
200
75
43
1.3
5.8
26
360.8
2.53
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
EW-3
255.0
80.46
174.5
6.2
260
270
130
1.6
21
87
775.8
2.26
1.2
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
EW-4
255.2
80.72
174.5
2.9
100
2200
1400
4.6
270
150
4127.5
1.96
3.5
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
EW-5
254.5
81
173.5
4
62
2200
1400
2.5
330
29
4027.5
1.89
8.7
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
CBW-1
259.4
49.93
209.5
1 U
1.8
1 U
1 U
1 U
1 U
1 U
7.8
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
6.41
0.3
4.4
*
15.46
-
-
-
-
-
CBW-4
341.4
176.9
164.5
1 U
8.9
1 U
0.82 J
1 U
1 U
1 U
14.72
2.89
0.5
NR
<0.025 UB
<0.025 UB
0.66 UB
145
N/A
1.87
0.018
1.89
26.6
<1.5 U
0
6.55
0.38
3.46
231
12.8
9.6
++++
mid E+4
5.87E+04
9.98E+04
1.65E+04
CBW-5
312.1
185.61
126.5
1 u
3
7.2
1 U
1 U
1 U
1 U
15.2
2.24
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
7.92
0.584
0.68
*
11.48
-
-
-
-
-
-
CBW-6
311.1
149.56
161.5
1 u
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.72
3.49
0.28
*
13.31
-
-
-
-
-
-
CBW-7
256.6
87.5
169.06
2.2 J
27
0.84 J
2.4
1 U
1 U
0.85 J
35.29
2.92
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.6
0.308
0.91
*
14.56
-
-
-
-
-
-
CBW-9
314.0
151.1
162.86
1 U
1.8
1 U
1 U
1 U
1 U
1 U
7.8
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.77
0.368
0.33
*
15.61
-
-
-
-
-
-
CBW-10
337.0
160.51
176.5
1 U
21
1 U
2.2
1 U
1 U
1.2
28.4
2.88
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.5
0.311
0.5
*
13.43
-
-
-
-
-
-
CBW-11
311.4
152
159.38
1 U
8.5
1 U
0.83 J
1 U
1 U
1 U
14.33
2.88
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.64
0.246
0.32
*
13.56
-
-
-
-
-
-
CH2M-1
256.2
82.72
173.5
36
1100
210
150
3.3
4.7
190 J
1694
2.70
0.67
NR
-
-
-
-
-
-
-
-
-
-
-
6.18
0.257
0.36
*
14.2
-
-
-
-
-
-
CH2M-2
339.5
191.01
148.5
1 U
21
1.5
1 U
1 U
1 U
1 U
27.5
2.91
1.3
NR
0.01 UB
<0.025 UB
0.13 JB
97.7
0.095
0.771
<0.01
0.771
15.3
<1.5 U
0
7.35
0.26
4.62
228
12.1
21.6
-
-
-
-
-
CH2M-3
247.2
83.74
163.5
1 U
4.6
1 U
1 U
1 U
1 U
1 U
10.6
3.00
0.5
NR
<0.025 UB
<0.025 UB
0.051 UB
111
N/A
4.62
0.03
4.65
18.8
<1.5 U
0
6.43
0.340
5.16
81
14.1
6.1
+++ (no TOD)
mid E+4
6.11E+04
7.37E+04
3.33E+04
CH2M-4
249.8
85.34
164.5
17 J
52
1 U
1 U
1 U
1 u
1 U
74
3.21
0.5
NR
<0.025 UB
<0.025 UB
0.072 UB
55
N/A
3.54
0.024
3.56
9.6
<1.5 U
0
6.32
0.190
8.50
247
14.0
5.2
++++
low E+5
1.26E+05
1.26E+05
8.90E+04
ICF-2
256.9
65
191.91
4.4 J
1300
1100
360
170.5 J
52
1.6
2988.5
2.33
6.1
NR
-
-
-
-
-
-
-
-
-
-
-
6.62
0.304
0.15
*
14.4
-
-
-
-
-
-
ICF-3
250.3
31.5
218.79
2 J
1.3
1 U
1 U
1 U
1 U
1.3
8.6
3.55
0.5
X
-
-
-
-
-
-
-
-
-
-
-
4.96
0.227
0.17
*
15.75
-
-
-
-
-
-
ICF-4
254.7
34.18
220.5
50 U
50 U
69
34 J
1 U
95
50 U
349
1.84
0.5
X
-
-
-
-
-
-
-
-
-
-
-
6.23
0.481
0.12
*
17.52
-
-
-
-
-
-
ICF-5D
254.7
50.19
204.5
42 J
190
2100
170
1.6
91
81
2675.6
2.02
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.28
0.354
0.14
*
14.88
-
-
-
-
-
-
ICF-5S
254.9
36.37
218.5
28 J
180
190
100
1 U
1.5
22
522.5
2.37
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
5.84
0.341
0.36
*
15.31
-
-
-
-
-
-
KRRF-1
254.4
73.9
180.5
2.1 J
79
36
20
1 U
1.7
3.7
143.5
2.49
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.43
0.26
0.1
*
14.35
-
-
-
-
-
-
MW-A
249.8
57
192.78
1 U
3.8
1 U
1 U
1 U
1 U
1 U
9.8
3.00
7.2
NR
-
-
-
-
-
-
-
-
-
-
-
7.47
0.135
0.32
*
12.05
-
-
-
-
-
-
MW-B
243.1
48.5
194.56
1 U
15
1.2
0.98 J
1 U
1 U
1 U
21.18
2.84
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.85
0.303
0.26
*
14.92
-
-
-
-
-
-
MW-C
252.1
41.6
210.48
8.8 J
260
89
82
2.7
8.6
38
489.1
2.49
1.2
NR
0.008 UB
0.021 UB
0.27 UB
35
N/A
2.89
0.026
2.92
20.1
6.7
0
6.05
0.150
6.50
266
17.3
12.5
-
-
-
-
-
TOW-10
255.5
71
184.5
1 U
2.3
1 U
1 U
1 U
1 U
1 U
8.3
3.00
14
NR
-
-
-
-
-
-
-
-
-
-
-
6.93
0.223
0.3
*
13.34
-
-
-
-
-
-
TOW-4
254.5
70
184.54
2.4 J
59
280
250
1.6
140
31
764
1.78
1.1
NR
-
-
-
-
-
-
-
-
-
-
-
6.48
0.259
0.17
*
13.54
-
-
-
-
-
-
TWT-10
323.5
167
156.5
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.72
0.374
0.19
*
12.32
-
-
-
-
-
-
WCC-1A
255.1
124.5
130.57
1 U
15
5.6
4.4
1 U
1.6
1 U
29.6
2.36
57
NR
-
-
-
-
-
-
-
-
-
-
-
7.66
0.161
0.13
*
13.59
-
-
-
-
-
-
WCC-1B
255.0
57.6
197.36
2.2 J
92
74
51
1 U
6.6
63 J
289.8
2.29
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.42
0.308
0.17
*
14.34
-
-
-
-
-
-
WCC-2
251.8
43.32
208.5
1 U
4.1
1 U
1 U
1 U
1 U
1 U
10.1
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.49
0.249
3.73
*
13.98
-
-
-
-
-
-
WCC-3
256.7
40
216.71
1 U
1.5
1 U
1 U
1 U
1 U
1 U
7.5
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.54
0.394
3.4
*
16.5
-
-
-
-
-
-
WCC-5
257.5
46.02
211.5
1.4 J
31
4.5
3.4
1 U
1.1
1 U
43.4
2.68
0.5
NR
0.01 UB
<0.025 UB
0.23 UB
54.8
N/A
2.08
0.018
2.1
12.8
<1.5 U
0
6.46
0.180
5.30
226
16.2
5.6
++++
low E+4
1.91E+04
4.96E+04
2.26E+04
WCC-6
256.9
58.4
198.53
1 U
17
1 U
1 U
1 U
1 U
1 U
23
3.00
0.5
NR
0.008 UB
<0.025 UB
0.1 UB
69.4
N/A
3.38
0.039
3.42
10
<1.5 U
0
6.43
0.210
12.93
192
14.9
21.2
-
-
-
-
-
WCSB-9
254.9
35
219.94
6.6 J
45
1.2
1 U
1 U
1 U
1 U
56.8
3.07
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.23
0.228
5.05
*
14.21
-
-
-
-
-
-
MW-301
254.5
144.5
109.95
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
42
NR
-
-
-
-
-
-
-
-
-
-
-
7.49
0.161
0.17
*
13.52
-
-
-
-
-
-
MW-302
254.4
103
151.4
1 U
15
17
5.8
2.7
21
1 U
63.5
1.58
360
NR
0.31
1.35
230
122
2.405
<.01 U
<.01 u
<.01 U
22.15
1.87
0.5
7.50
0.410
2.95
113
14.5
203.0
-
-
-
-
-
MW-304
254.9
145.5
109.37
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
13
NR
-
-
-
-
-
-
-
-
-
-
-
7.52
0.143
0.26
*
11.15
-
-
-
-
-
-
MW-305
254.9
104.5
150.41
1 U
1 U
2.1
1 U
1 U
2.6
1 U
9.7
1.34
300
NR
-
-
-
-
-
-
-
-
-
-
-
7.73
0.318
0.5
*
12.22
-
-
-
-
-
-
MW-306
253.8
144.5
109.27
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
4.4
NR
-
-
-
-
-
-
-
-
-
-
-
7.55
0.164
0.13
*
13.3
-
-
-
-
-
-
MW-307
255.3
150
105.28
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
10
NR
-
-
-
-
-
-
-
-
-
-
-
7.51
0.132
0.21
*
12.51
-
-
-
-
-
-
MW-308
257.0
151.25
105.78
1 U
15
6
1.7
1 U
0.81
1 U
26.51
2.01
6.8
NR
0.041 JB
0.16 JB
14
96.7
N/A
0.011
<.01 UB
0.011
16.4
<1.5
0.6
7.43
0.270
5.75
122
13.3
78.8
-
-
-
-
-
MW-89.7
315.0
56.29
258.71
1 U
1 U
1 U
1 U
1 U
1 U
1 U
7
0.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
6.88
1.259
0.11
*
15.1
-
-
-
-
-
-
WELL 12A
323.5
157.5
166
1 U
1.4
1 U
1 U
1 U
1 U
1 U
7.4
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
WELL 9A
294.0
181.5
112.5
1 U
1.2
1 U
1 U
1 U
1 U
1 U
7.2
3.00
0.5
NR
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Notes:
X- LNAPL Present (Light Non Aqueous Phase Liquid)
N/A - Not Available
PCE - Tetrachloroethene; TCE- Trichloroethene; cDCE- Cis-1,2 dichloroethene; tDCE- Trans-1,2-dichloroethene; VC-Vinyl Chloride; PCA-Perchloroethane
| Field Parameter data - June 2008
Field Parameter data - Feb/Mar 2008
Value indicates Aerobic conditions
Value, or TCE degradation chain, Indicates Anaerobic conditions
- Indicates Data not collected
EAP - Enzyme Activity Probe; PA - Phenyl acetylene; 3HPA: 3- Hydroxy-Phenyl acetylene; CINN: Cinnamonitrile;
+ A positive result indicates the gene of interest was amplified and no recorded result indicates amplification was not successful
(for e.g., Well CH2M3 DNA = (+++ no TOD) implies amplification was not successful by TOD)
Genes of interest
sMMO soluble methane monooxygenase
PHE Toluene2,3,4-m onooxyg en ase
TOD Tolune/xylene monooxygenase
RMO Toluene3,4mon ooxyg enase
- MNA Data only collection in June 2008 at nine wells
- MW 302 Results are an average of environmental samples and duplicate for MNA data (June 2008)
- CBW-7, ICF-2, ICF-3 and WCC-5 results are the higher of the environmental sample and duplicate for chlorinated compounds (Feb/Mar 2008)
(1) - CI# (chloride number) is based on PCE, TCE, cDCE, tDCE, 11DCE and VC concentrations
* - ORP data from Feb/Mar 2008 not used
NR - None Reported.
J - Analyte present. Reported value may not be accurate or precise.
U - Not detected at or above the reported value
Anaerobic indicators: Methane > 0.5 ug/L, Fe++ > 2 mg/L, N03 < 1 mg-N/L, S04 <20 mg/L, DO < 1 mg/L
All Sample Parameters
Analytes that were not detected at or above the reported value were qualified as "U".
Ethane Specific Parameters
Non-detect samples or those detected at >2x RL were not qualified.
Sample results detected at concentrations 5x trip blank concentration were not qualified.
Sample results detected at concentrations RL but less than trip blank concentration were reported as non-detects, or "UB".
Sample results detected at concentrations >RL but <5x trip blank concentration were qualified as estimated, "JB".
Previous LNAPL Detected Wells : ICF -3, ICF -4; NAPL has been detected at other site wells in source area, But they have been abandoned and were not sampled in 2008
CDM
Page 1 of 1
-------
Appendix C
Johnson and Ettinger Screening Results
Memorandum
-------
893 Old E»gi» School ROM, Sum 408
Wnyns, Pennsylvania 19097
tot; $10295-0450
rax: 010 293-1920
August 4, 2008
Kira Lynch
US EPA Region 10
Office of Environmental Cleanup (ECL-113)
1200 Sixth Avenue, Suite 900
Seattle WA 98101
Subject: Johnson and Ettinger Screening Results Memorandum Well 12A Focused Feasibility
Study
Dear Ms. Lynch:
Please find enclosed the revised draft of the Well 12A Johnson and Ettinger Screening Results
Memorandum. The draft memorandum was submitted to you on June 13,2008, This
memorandum is being submitted as partial fulfillment of the reporting requirements for this
assignment.
If you have any questions, call me at (610) 293-0450,
Sincerely,
Aaron R. Frantz, P.E., P.G. \
Project Manager
CDM Federal Programs Corporation
-------
Revised Draft
Well 12A Johnson and Ettinger Screening Results Memorandum
August 4,2008
The health risk at the Well 12A Site due to vapor intrusion was evaluated using the Johnson and
Ettinger model (EPA 2004) since volatile organic compounds (VOCs) may migrate from
groundwater through the subsurface and into buildings at the Site.
Introduction
Groundwater contaminant concentrations are historically highest near the machine shop which
is located immediately south of the former Time Oil Building. The machine shop is a 200 feet
long x 140 feet wide one-story structure. Therefore, the maximum detected groundwater
concentrations of the February/March 2008 sampling events for the six main chlorinated VOCs
(trichloroethene, tetrachloroethene, 1,1,2,2-tetrachloroethane; ds-1,2-dichloroethene, trans-],2-
dichloroethene, and vinyl chloride) within 100 feet in depth and in close proximity to the
machine shop building were compared to generic screening levels provided by EPA in Table 2c
of Subsurface Vapor Intrusion Guidance (2002). Target groundwater concentrations corresponding
to a cancer risk of 10 6 or a hazard quotient of 1 in Table 2c are used as screening levels. This
screen indicates that there is a potential for migration of vapors for all six chlorinated VOCs in
the vicinity of the machine shop.
Johnson and Ettinger Modeling
The Johnson and Ettinger model (EPA 2004) is used to estimate the indoor air concentrations of
volatile chemicals from groundwater. The model is calibrated to parameters listed in Table 1.
The maximum concentrations are served as inputs for the Johnson and Ettinger model. The
calculated indoor air concentrations (Table 2) are used to estimate potential risks for identified
potential receptors at the site, onsite workers and nearby residents (adult and child, 0 to 6 years
old).
Exposure assumptions were taken from EPA documents (EPA 1989,1991,1997). EPA's standard
default assumptions (EPA 1991) are used, where available. Otherwise values from the most
recent guidance available were used. Risks for all receptors are estimated using reasonable
maximum exposure (RME) assumptions. Risks are also estimated using central tendency
exposure (CTE) assumptions in cases where the RME assumptions resulted in risk estimates
above EPA thresholds. CTE risks represent typical exposure patterns rather than reasonable
maximum exposures. The hazard index (HI) for all receptors are also estimated using RME
assumptions. His are also estimated using CTE assumptions in cases where the RME
assumptions resulted in His above EPA thresholds. The calculated cancer risks and non-cancer
health hazards are presented in Tables 3, 4, and 5 for onsite workers, adult residents, and child
residents, respectively.
The cancer risks for all receptors are above the EPA target range of 1 x 10 6 to 1 x 10-4 under the
RME and CTE scenario, except for onsite worker where the cancer risk falls within the EPA
target range of 1 x 10 6 to 1 x 10 4 under the CTE scenario. The major risk driver for the
-------
estimated risk is TCE. Therefore, further investigation for vapor intrusion may be warranted at
the site.
The total His for all receptors is below the threshold of unity (1) under RME scenario, except for
child residents. However, under the CTE scenario, the His is below the threshold of unity for
child residents. This indicates that non-cancer health effects will most likely not occur for all
receptors at the site.
Model Uncertainty
Groundwater data from February/March 2008 were used for this evaluation since it is the most
current data set available. The building considered in the evaluation was used since it was at
the core of the highest concentrations of CVOCs detected in groundwater. If other data or risk
scenarios were incorporated into the evaluation, greater risk may be estimated. Other data or
risk scenarios may include, for example:
¦ Groundwater contaminated with TCE, and other constituents, at higher concentrations
than what was reported/ detected in 2008
¦ DNAPL with TCE below the former Time Oil building
¦ Contaminated soil below the former Time Oil building
¦ Elevated soil gas concentrations below the former Time Oil building
Incorporating these elements into the evaluation would likely result in risks higher than
currently estimated.
Additionally, residential exposure was one of the scenarios evaluated in this screening, but the
scenario may not be representative since the site is zoned for industrial use and it has not been
confirmed that people are living on the property.
Lastly, the Johnson and Ettinger Model was developed for screening level analysis. The tool is a
one-dimensional solution to diffusive and convective transport of vapors into indoor air and
has inherent assumptions and limitations associated with contaminant distribution, lithologic
characteristics, transport properties and pathways, and building characteristics. Therefore, the
results of the model should be considered as a general evaluation of site issues. Additional and
more specific analyses (e.g., building vapor sampling) may be required to quantify the risk.
References
EPA. 1989. Risk Assessment Guidance for Superfund: Human Health Evaluation Manual, Part A,
EPA/540/1-89/002. EPA Office of Emergency and Remedial Response, Washington, D.C.,
OSWER Directive 9285.701A. NTIS PB90-155581.
EPA. 1991. Human Health Evaluation Manual, Supplemental Guidance: Standard Default Exposure
Factors. March 25.
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-
01/002. External Review Draft. August.
EPA. 2002. OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from
-------
groundwater and Soils (Subsurface Vapor intrusion Guidance). EPA 530-D-02-004. November.
EPA. 2004. User's Guide for Evaluating Subsurface Vapor Intrusion Into Buildings (Revised).
Website http://ivww.epa.gov/oswer/riskassessment/airmodel/pdf/2004_0222_3phase_users _guide.pdf.
February 22.
-------
TABLE 1
INPUT PARAMETERS FOR VAPOR INTRUSION FROM GROUNDWATEF
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Parameter
Units
Default
Value
Used
Basis/Source of Value Used
Depth below grade to bottom of enclosed space floor
Lf
cm
15
15
Default (EPA 2004) depth to base of
foundation - slab-on-grade scenario
Depth below grade to water table
Lwr
cm
NA
(site-specific)
1,067
February/March 2008 water level
Average soil/groundwater temperature
Ts
°C
10
16.3
URS 2005
Thickness of soil stratum A (soil type below the
enclosed space floor)
hA
cm
NA
(site-specific)
1,067
URS 2005
Thickness of soil stratum B
cm
NA
(site-specific)
0
No second layer between groundwater
and ground surface.
Thickness of soil stratum C
he
cm
NA
(site-specific)
0
No third layer between groundwater
and ground surface.
Stratum A SCS soil type (used to est. soil vapor
permeability)
NA
(site-specific)
S
The unsaturated zone is primarily sand
and gravel (URS 2005)
Stratum A soil dry bulk density
PbA
g/cm3
1.66
1.86
URS 2005
Stratum A soil total porosity
nA
unitless
0.375
0.3
URS 2005
Stratum A soil water-filled porosity
ewA
cm3/cm3
0.054
0.054
Deafult (EPA 2004)
Stratum B SCS soil type
NA
NA
No second layer.
Stratum B soil dry bulk density
PbB
g/cm3
NA
NA
Stratum B soil total porosity
nB
unitless
NA
NA
Stratum B soil water-filled porosity
ewB
cm3/cm3
NA
NA
Stratum C SCS soil type
NA
NA
No third layer.
Stratum C soil dry bulk density
PbC
g/cm3
NA
NA
Stratum C soil total porosity
nc
unitless
NA
NA
Stratum C soil water-filled porosity
ewc
cm3/cm3
NA
NA
Enclosed space floor thickness
L crack
cm
10
10
Default (EPA 2004)
Soil-bldg pressure differential
AP
g/cm-s2
40
40
Default (EPA 2004) - equal to 4 Pa
Enclosed space floor length
Lb
cm
NA
(site-specific)
4,206
Measured from site map
Enclosed space floor width
WB
cm
NA
(site-specific)
3,962
Measured from site map
Enclosed space height
Hb
cm
NA
(site-specific)
244
Single story structure
Floor-wall seam crack width
w
cm
0.1
0.1
Default (EPA 2004)
Indoor air exchanne rate
ER
1/h
0.25
0.25
Default (FPA 20041
EPA 2004: User's Guide for Evaluating Subsurface Vapor Intrusion Into Buildings (Revised). February 22.
http://www.epa.gov/oswer/riskassessment/airmodel/pdf/2004_0222_3phase_users_guide.pdf
URS. 2005. Draft Final Field Investigation and Capture Zone Analysis Report, Commencement Bay South Tacoma Channel/Well 12A Superfund Site Tacoma,
Washington. September
See following page for supporting documentation.
-------
1. Depth Below Grade to Water Table
Elevation of GW table below building based on February/March 2008 water levels = 217 ft NGVD
Elevation of land surface based on site topograhy = 252 ft NGVD
252 - 217 = 35 ft = 1,067 cm
2. Groundwater temperature = 16.3 °C (URS 2005 - Table 31-2; mean of source area wells)
3. Thickness of soil stratum: - sat. and vadose zone in consistent stratum, therefore 35 ft = 1,067 cm
4. Dry bulk density and total porosity
Tot Porosity
Dry Bulk Density
unitless
g/cm3
302PTS-1
0.386
1.66
302PTS-2
0.384
1.66
302PTS-3
0.298
1.89
305PTS-1
0.328
1.84
306PTS-1
0.206
2.14
307PTS-1
0.278
1.95
308PTS-1
0.293
1.9
GEO AVG
0.30
1.86
Values from URS 2005
5. Water filled porosity - no value in URS 2005, therefore use EPA Default vlaue 0.054 cm3/cm3
6. Enclosed space floor length - building is comprised of three rectangular sections that total to an area of 17,904 SQ FT
The width and length of the three sections (in FT) are 50 x 30; 120 x 132 and 20 x 30.
Use L= 138 ft = 4,206 cm
Use W = 130 ft = 3,962 cm
138 ft x 130 ft = 17,940 SQ FT
7. Groundwater Concentrations for the Six Main Site CVOCs at Wells within 100 feet of J-E Serening Building
Station ID
Units
PCE
TCE
Cis-1,2-DCE
Trans-1,2-DCE
Vinyl-CI
1,1,2,2-PCA
CH2M-1
ug/L
36
1100
210
150
4.7
••-v v vv-::
EW-1
ug/L
1.9
73
24
14
2.7
3.3
EW-2
ug/L
9.7
200
75
43
5.8
26
EW-3
ug/L
6.2
260
270
130
21
87
EW-4
ug/L
2.9
100
2200
1400
3270";v v vv
150
WCC-1A
ug/L
1
15
5.6
4.4
1.6
1
WCC-1 B
ug/L
2.2
92
74
51
6.6
63
MW-302
ug/L
1
15
17
5.8
21
1
ICF-5D
ug/L
42
190
2100
170
91
81
ICF-5S
ug/L
28
180
190
100
1.5
22
Highest value for contaminant
Deep well; do not use
Concentrations from February/March 2008 Sampling Event
-------
F:\North Penn 7 016\GIS\ArcGIS Projects\RI\Figure 02 03 Site Map and Well Locations Screening Results Memo.mxd
Former Time Oil Building
ICF-4
Building Removed
February 2004
MW-8
Ngt Located
"See Note 3
Former East Tank Farm
Filter Cake Currently Located
Beneath Concrete Pad
,TOW-4
MW-13 EW-6
VES Building
WCSB-9
TOW-8 \ \
TOW-7
GETS Trailer
Building being considered
CH2M-1
Legend
Groundwater Extraction Well
Groundwater Monitoring Well
Soil Gas Monitoring Well
Soil Gas Extraction Well
Approximate Area of Filter Cake/Soil Excavation
CDM
Well 12A Superfund Site
Tacoma, Washington
Figure 1
Site Map and Well Locations
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
PCE
General Statistics
Number ofValid Samples 10
Number ofUnique Samples i
Raw Statistics
Minimum 1
Maximum 42
Mean 13.09
Median 4.55
SD 15.92
Coefficient of Variation 1.216
Skewness 1.096
Log-transformed Statistics
Minimum of Log Data 0
Maximum of Log Data 3.738
Mean of log Data 1.725
SD of log Data 1.447
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.762 Shapiro WilkTest Statistic 0.898
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data not Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 22.32
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 23.24
95% Modified-t UCL 22.61
Assuming Lognormal Distribution
95% H-UCL 114.4
95% Chebyshev (MVUE) UCL 41.76
97.5% Chebyshev (MVUE) UCL 54.02
99% Chebyshev (MVUE) UCL 78.1
Gamma Distribution Test
k star (bias corrected) 0.565
Theta Star 23.18
nu star 11.3
Approximate Chi Square Value (.05) 4.767
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 4.055
Anderson-Darling Test Statistic 0.601
Anderson-Darling 5% Critical Value 0.76
Kolmogorov-Smirnov Test Statistic 0.224
Kolmogorov-Smirnov 5% Critical Value 0.277
Data appear Gamma Distributed at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 31.02
95% Adjusted Gamma UCL 36.46
Potential UCL to Use
Data Distribution
Data appear Gamma Distributed at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
21.37
95% Jackknife
UCL
22.32
95% Standard Bootstrap
UCL
20.89
95% Bootstrap-t
UCL
26.59
95% Hall's Bootstrap
UCL
20.02
95% Percentile Bootstrap
UCL
21.69
95% BCA Bootstrap
UCL
22.47
95% Chebyshev(Mean, Sd)
UCL
35.04
97.5% Chebyshev(Mean, Sd)
UCL
44.54
99% Chebyshev(Mean, Sd)
UCL
63.19
Use 95% Approximate Gamma UCL 31.02
CDM
Page 1 of 13
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
TCE
General Statistics
Number ofValid Samples 10
Number ofUnique Samples i
Raw Statistics
Minimum 15
Maximum 1100
Mean 222.5
Median 140
SD 318.9
Coefficient of Variation 1.433
Skewness 2.785
Log-transformed Statistics
Minimum of Log Data 2.708
Maximum of Log Data 7.003
Mean of log Data 4.714
SD of log Data 1.295
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.608 Shapiro WilkTest Statistic 0.923
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data not Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 407.4
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 483.3
95% Modified-t UCL 422.2
Assuming Lognormal Distribution
95% H-UCL 1294
95% Chebyshev (MVUE) UCL 654
97.5% Chebyshev (MVUE) UCL 838.9
99% Chebyshev (MVUE) UCL 1202
Gamma Distribution Test
k star (bias corrected) 0.663
Theta Star 335.7
nu star 13.25
Approximate Chi Square Value (.05) 6.064
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 5.243
Anderson-Darling Test Statistic 0.489
Anderson-Darling 5% Critical Value 0.753
Kolmogorov-Smirnov Test Statistic 0.205
Kolmogorov-Smirnov 5% Critical Value 0.275
Data appear Gamma Distributed at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 486.3
95% Adjusted Gamma UCL 562.5
Potential UCL to Use
Data Distribution
Data appear Gamma Distributed at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
388.4
95% Jackknife
UCL
407.4
95% Standard Bootstrap
UCL
377.4
95% Bootstrap-t
UCL
754.3
95% Hall's Bootstrap
UCL
1084
95% Percentile Bootstrap
UCL
412.1
95% BCA Bootstrap
UCL
478
95% Chebyshev(Mean, Sd)
UCL
662.1
97.5% Chebyshev(Mean, Sd)
UCL
852.3
99% Chebyshev(Mean, Sd)
UCL
1226
Use 95% Approximate Gamma UCL 486.3
CDM
Page 2 of 13
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
cis-1,2-DCE
General Statistics
Number ofValid Samples 10
Number ofUnique Samples 10
Raw Statistics
Minimum 5.6
Maximum 2200
Mean 516.6
Median 132.5
SD 865.8
Coefficient of Variation 1.676
Skewness 1.736
Log-transformed Statistics
Minimum of Log Data 1.723
Maximum of Log Data 7.696
Mean of log Data 4.789
SD of log Data 1.946
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.604 Shapiro WilkTest Statistic 0.952
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data not Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 1018
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 1128
95% Modified-t UCL 1044
Assuming Lognormal Distribution
95% H-UCL 24331
95% Chebyshev (MVUE) UCL 2042
97.5% Chebyshev (MVUE) UCL 2691
99% Chebyshev (MVUE) UCL 3966
Gamma Distribution Test
k star (bias corrected) 0.377
Theta Star 1369
nu star 7.548
Approximate Chi Square Value (.05) 2.476
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 2.002
Anderson-Darling Test Statistic 0.63
Anderson-Darling 5% Critical Value 0.787
Kolmogorov-Smirnov Test Statistic 0.249
Kolmogorov-Smirnov 5% Critical Value 0.283
Data appear Gamma Distributed at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 1575
95% Adjusted Gamma UCL 1948
Potential UCL to Use
Data Distribution
Data appear Gamma Distributed at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
966.9
95% Jackknife
UCL
1018
95% Standard Bootstrap
UCL
943.1
95% Bootstrap-t
UCL
4203
95% Hall's Bootstrap
UCL
4382
95% Percentile Bootstrap
UCL
943.6
95% BCA Bootstrap
UCL
1133
95% Chebyshev(Mean, Sd)
UCL
1710
97.5% Chebyshev(Mean, Sd)
UCL
2226
99% Chebyshev(Mean, Sd)
UCL
3241
Use 95% Adjusted Gamma UCL 1948
CDM
Page 3 of 13
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
trans-1,2-DCE
General Statistics
Number ofValid Samples 10
Number ofUnique Samples 10
Raw Statistics
Minimum 4.4
Maximum 1400
Mean 206.8
Median 75.5
SD 423.6
Coefficient of Variation 2.048
Skewness 3.042
Log-transformed Statistics
Minimum of Log Data 1.482
Maximum of Log Data 7.244
Mean of log Data 4.043
SD of log Data 1.739
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.498 Shapiro WilkTest Statistic 0.951
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data not Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 452.4
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 564.9
95% Modified-t UCL 473.9
Assuming Lognormal Distribution
95% H-UCL 4106
95% Chebyshev (MVUE) UCL 683
97.5% Chebyshev (MVUE) UCL 894.4
99% Chebyshev (MVUE) UCL 1309
Gamma Distribution Test
k star (bias corrected) 0.412
Theta Star 501.5
nu star 8.249
Approximate Chi Square Value (.05) 2.88
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 2.358
Anderson-Darling Test Statistic 0.595
Anderson-Darling 5% Critical Value 0.778
Kolmogorov-Smirnov Test Statistic 0.263
Kolmogorov-Smirnov 5% Critical Value 0.281
Data appear Gamma Distributed at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 592.4
95% Adjusted Gamma UCL 723.6
Potential UCL to Use
Data Distribution
Data appear Gamma Distributed at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
427.2
95% Jackknife
UCL
452.4
95% Standard Bootstrap
UCL
409.9
95% Bootstrap-t
UCL
1385
95% Hall's Bootstrap
UCL
1394
95% Percentile Bootstrap
UCL
462.6
95% BCA Bootstrap
UCL
596
95% Chebyshev(Mean, Sd)
UCL
790.8
97.5% Chebyshev(Mean, Sd)
UCL
1043
99% Chebyshev(Mean, Sd)
UCL
1540
Use 95% Adjusted Gamma UCL 723.6
CDM
Page 4 of 13
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
VC
General Statistics
Number ofValid Samples 10
Number ofUnique Samples 9
Raw Statistics
Minimum 1.5
Maximum 270
Mean 42.59
Median 6.2
SD 84.35
Coefficient of Variation 1.981
Skewness 2.662
Log-transformed Statistics
Minimum of Log Data 0.405
Maximum of Log Data 5.598
Mean of log Data 2.326
SD of log Data 1.717
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.561 Shapiro WilkTest Statistic 0.918
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data not Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 91.49
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 110.5
95% Modified-t UCL 95.23
Assuming Lognormal Distribution
95% H-UCL 665.9
95% Chebyshev (MVUE) UCL 118.3
97.5% Chebyshev (MVUE) UCL 154.8
99% Chebyshev (MVUE) UCL 226.4
Gamma Distribution Test
k star (bias corrected) 0.383
Theta Star 111.1
nu star 7.669
Approximate Chi Square Value (.05) 2.545
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 2.062
Anderson-Darling Test Statistic 0.83
Anderson-Darling 5% Critical Value 0.786
Kolmogorov-Smirnov Test Statistic 0.268
Kolmogorov-Smirnov 5% Critical Value 0.283
Data follow Appr. Gamma Distribution at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 128.3
95% Adjusted Gamma UCL 158.4
Potential UCL to Use
Data Distribution
Data Follow Appr. Gamma Distribution at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
86.46
95% Jackknife
UCL
91.49
95% Standard Bootstrap
UCL
83.21
95% Bootstrap-t
UCL
397.9
95% Hall's Bootstrap
UCL
302.2
95% Percentile Bootstrap
UCL
87.21
95% BCA Bootstrap
UCL
120.4
95% Chebyshev(Mean, Sd)
UCL
158.9
97.5% Chebyshev(Mean, Sd)
UCL
209.2
99% Chebyshev(Mean, Sd)
UCL
308
Use 95% Adjusted Gamma UCL 158.4
CDM
Page 5 of 13
-------
General UCL Statistics for Full Data Sets
User Selected Options
From File WorkSheet.wst
Full Precision OFF
Confidence Coefficient 95%
Number of Bootstrap Operations 2000
1,1,2,2-PCA
General Statistics
Number of Valid Samples 10 Number ofUnique Samples i
Raw Statistics
Minimum 1
Maximum 190
Mean 62.43
Median 44.5
SD 65.74
Coefficient of Variation 1.053
Skewness 0.97
Log-transformed Statistics
Minimum of Log Data 0
Maximum of Log Data 5.247
Mean of log Data 3.08
SD of log Data 1.993
Relevant UCL Statistics
Normal Distribution Test Lognormal Distribution Test
Shapiro Wilk Test Statistic 0.872 Shapiro WilkTest Statistic 0.863
Shapiro Wilk Critical Value 0.842 Shapiro Wilk Critical Value 0.842
Data appear Normal at 5% Significance Level Data appear Lognormal at 5% Significance Level
Assuming Normal Distribution
95% Studenfs-t UCL 100.5
95% UCLs (Adjusted for Skewness)
95% Adjusted-CLT UCL 103.4
95% Modified-t UCL 101.6
Assuming Lognormal Distribution
95% H-UCL 5666
95% Chebyshev (MVUE) UCL 400.8
97.5% Chebyshev (MVUE) UCL 528.8
99% Chebyshev (MVUE) UCL 780.4
Gamma Distribution Test
k star (bias corrected) 0.478
Theta Star 130.5
nu star 9.568
Approximate Chi Square Value (.05) 3.673
Adjusted Level of Significance 0.0267
Adjusted Chi Square Value 3.066
Anderson-Darling Test Statistic 0.373
Anderson-Darling 5% Critical Value 0.77
Kolmogorov-Smirnov Test Statistic 0.172
Kolmogorov-Smirnov 5% Critical Value 0.279
Data appear Gamma Distributed at 5% Significance Level
Assuming Gamma Distribution
95% Approximate Gamma UCL 162.6
95% Adjusted Gamma UCL 194.8
Potential UCL to Use
Data Distribution
Data appear Normal at 5% Significance Level
Nonparametric Statistics
95% CLT
UCL
96.63
95% Jackknife
UCL
100.5
95% Standard Bootstrap
UCL
94.42
95% Bootstrap-t
UCL
110.5
95% Hall's Bootstrap
UCL
117.1
95% Percentile Bootstrap
UCL
95.13
95% BCA Bootstrap
UCL
100.4
95% Chebyshev(Mean, Sd)
UCL
153
97.5% Chebyshev(Mean, Sd)
UCL
192.3
99% Chebyshev(Mean, Sd)
UCL
269.3
Use 95% Student's-t UCL 100.5
CDM
Page 6 of 13
-------
TABLE 2
INDOOR AIR EXPOSURE POINT CONCENTRATIONS FROM VAPOR INTRUSION
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Maximum
Vapor Intrusion
Exceeds
Estimated Indoor
Chemical
Concentration (1)
Screening Level (2)
screening
Air Concentration (3)
(|jg/L)
(|jg/L)
level?
(|jg/m3)
1,1,2,2-Tetrachloroethane
190
3
YES
0.21
c/s-1,2,-Dichloroethene
2,200
210
YES
20.4
Tetrachloroethene
42
0.11
YES
1.37
trans-1,2-Dichloroethene
1,400
180
YES
27.4
Trichloroethene
1,100
0.053
YES
23.2
Vinyl Chloride
270
0.25
YES
21.2
(1) Maximum detected concentration from shallow groundwater
(2) EPA. 2002. Draft Guidance for Evaluating the Vapor Instrusion to Indoor Air Pathway from Groundwater
http://www.epa.gov/correctiveaction/eis/vapor/tables.pdf
Table 2c: Generic Screening Levels and Summary Sheet. Based on noncancer hazard index of 1 and cancer risk of 1 x10"6.
For value based upon MCL, refers to Table 2a (present screening values for the 1x10"4 risk level) and then adjust the value
to a 1x10"6 value.
(3) Estimated using exposure point concentration in EPA's Johnson & Ettinger vapor intrusion model spreadsheet:
http://www.epa.gov/oswer/riskassessment/airmodel/johnson_ettinger.htm
Weill2A JE DrftTables
Page 7 of 13
8/5/2008
-------
TABLE 3
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - ONSITE WORKERS
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CAx CSFx IRx ETx CF1 x EFx ED) / (BWx ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
1.3E-07
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
6.6E-07
NA
NA
NA
IR
inhalation rate (m3/hr)
0.83
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
8
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
2.2E-04
4.0E-02
1.1E-02
0.13
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
7.6E-06
1.0E-01
2.9E-02
0.05
EF
exposure frequency (d/yr)
250
EPA 1991
ED
exposure duration (yrs)
25
EPA 1991
BW
body weight (kg)
70
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
9,125
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
2E-04
Hazard Index =
0.2
CDM
8/5/2008
-------
TABLE 4
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - RESIDENTIAL ADULTS
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CA x CSF x IR x ET x CF1 x EF x ED) / (BW x ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
5.1E-07
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
2.6E-06
NA
NA
NA
IR
inhalation rate (m3/hr)
0.83
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
24
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
8.7E-04
4.0E-02
1.1E-02
0.6
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
3.1E-05
1.0E-01
2.9E-02
0.2
EF
exposure frequency (d/yr)
350
EPA 1991
ED
exposure duration (yrs)
24
EPA 1991
BW
body weight (kg)
70
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
8,760
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
9E-04
Hazard Index =
0.8
CDM
8/5/2008
-------
TABLE 5
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - RESIDENTIAL CHILDREN
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CAx CSFx IRx ETx CF1 x EFx ED) / (BWx ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
3.6E-07
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
1.9E-06
NA
NA
NA
IR
inhalation rate (m3/hr)
0.5
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
24
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
6.1E-04
4.0E-02
1.1E-02
1.6
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
2.1E-05
1.0E-01
2.9E-02
0.6
EF
exposure frequency (d/yr)
350
EPA 1991
ED
exposure duration (yrs)
6
EPA 1991
BW
body weight (kg)
15
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
2,190
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
6E-04
Hazard Index =
CDM
8/5/2008
-------
TABLE 3
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - ONSITE WORKERS
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CA x CSF x IR x ET x CF1 x EF x ED) / (BW x ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
3.1E-08
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
1.6E-07
NA
NA
NA
IR
inhalation rate (m3/hr)
0.63
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
8
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
5.3E-05
4.0E-02
1.1E-02
0.09
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
1.9E-06
1.0E-01
2.9E-02
0.03
EF
exposure frequency (d/yr)
225
EPA 1997
ED
exposure duration (yrs)
9
EPA 1997
BW
body weight (kg)
70
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
3,285
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
6E-05
Hazard Index =
0.1
CDM
8/5/2008
-------
TABLE 4
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - RESIDENTIAL ADULTS
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CAx CSFx IRx ETx CF1 x EFx ED) / (BWx ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
9.7E-08
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
5.0E-07
NA
NA
NA
IR
inhalation rate (m3/hr)
0.63
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
16
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
1.6E-04
4.0E-02
1.1E-02
0.3
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
5.8E-06
1.0E-01
2.9E-02
0.1
EF
exposure frequency (d/yr)
350
EPA 1991
ED
exposure duration (yrs)
9
EPA 1991
BW
body weight (kg)
70
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
3,285
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
2E-04
Hazard Index =
0.4
CDM
8/5/2008
-------
TABLE 5
CALCULATION OF CHEMICAL CANCER RISKS AND NON-CANCER HAZARDS - RESIDENTIAL CHILDREN
South Tacoma Channel / Well 12A Site
Tacoma, Washington
Equation Definition:
Indoor Air
Cancer Risk
Noncancer Hazard
Excess Risk =
(CA x CSF x IR x ET x CF1 x EF x ED) / (BW x ATC)
Chemical of Concern
Concentration
Unit Risk
CSF
Excess Cancer
Inhalation RfC
Extrapolated RfD
Hazard
HQ = (CAx IRxCFI x EF x ED) / (RfD x BW x ATNC)
(|jg/m3)
(|jg/m3)-1
(mg/kg-day)'1
Risk
(mg/m3)
(mg/kg-day)
Quotient
Parameter
Definition
Value
Source
CA
chemical-specific concentration in air (|jg/m3)
chemical-specific
J&E Model
1,1,2,2-Tetrachloroethane
0.21
7.4E-06
2.6E-02
1.4E-07
NA
NA
NA
CSF
inhalation cancer slope factor (mg/kg/day)"1
chemical-specific
-
c/'s -1,2,-Dichloroethene
20.4
NA
NA
NA
NA
NA
NA
RfD
inhalation reference dose (mg/kg/day)
chemical-specific
-
Tetrachloroethene
1.37
5.9E-06
2.1E-02
7.4E-07
NA
NA
NA
IR
inhalation rate (m3/hr)
0.3
EPA 1997
trans-1,2-Dichloroethene
27.4
NA
NA
NA
NA
NA
NA
ET
exposure time (hr/day)
16
EPA 1997
Trichloroethene
23.2
1.1E-04
4.0E-01
2.4E-04
4.0E-02
1.1E-02
0.6
CF1
conversion factor (mg/|jg)
1E-03
-
Vinyl Chloride
21.2
4.4E-06
1.5E-02
8.6E-06
1.0E-01
2.9E-02
0.2
EF
exposure frequency (d/yr)
350
EPA 1991
ED
exposure duration (yrs)
6
EPA 1991
BW
body weight (kg)
15
EPA 1991
ATC
cancer -averaging time (days)
25,550
EPA 1989
atnc
Noncancer average time (days)
2,190
EPA 1989
Total Excess Cancer Risk =
Exposure Parameter Sources:
EPA 1989. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Part A.
EPA 1991. Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual, Supplemental Guidance, Standard Default Exposure Factors. Interim Final.
EPA 1997. Exposure Factors Handbook. Vol. 1: General Factors. ORD. EPA/600/P-95/002Fa.
Toxicity Value Sources:
EPA. 2001. Trichloroethylene Health Risk Assessment: Synthesis and Characterization. EPA/600/P-01/002. External Review Draft. August.
EPA. 2008. Integrated Risk Information System (IRIS). June 10.
3E-04
Hazard Index =
0.9
CDM
8/5/2008
-------
Appendix D
Hydrogeological Analysis
-------
Hydrogeological Analysis
Purpose: Estimate steady state contaminant concentrations reductions necessary at east side of plume and south-southwest side of plume
to achieve TCE concentrations to below the MCL of 5 ug/l
Steady state transport solution along the centerline of a plume (Domenico 1987)
C(x) = C oexp{x/2ax[l - y/l + 4 Xou / v]}
{erf[Y / 4ayx]erf[(Z I A) I-Joczx]}
where, C0= initial concentration (ug/l);
y = length of source area perpendicular to groundwater flow (feet);
Z = depth of source area below water table (feet);
x = location along x axis (feet) from source on plume centerline
a x,j,z= dispersivity in x, y and z directions (feet)
v= velocity of contaminant (feet/day)1 (Vgw/Rf)
X = decay constant (day"1)
East gradient direction:
C0=
300 ug/l
Average concentration where subsurface turns from anaerobic to aerobic zone
y =
1050 ft
Distance from CBW-10 to WCC-2
z =
33 ft
Midpoint depth of saturated zone (estimated to be average source depth)
X =
520 ft
Distance from 300 ug/l isoconcentration to CH2M-2
a x,y,z =
36, 3.6, 0.4
Contaminant Source Strength and Sensitivity Analysis (CDM 2008)
V =
0.04 ft/d
Contaminant Source Strength and Sensitivity Analysis (CDM 2008)
A =
8.25 yrs
Biodegradation rate needed to achieve the observed 21 ug/l TCE
concentration (Feb/Mar 2008) with the given parameters and solution
South-southwest gradient C0=
y =
z =
X =
a x,y,z =
V =
A =
concentration (Feb/Mar 2008) with the given parameters and solution
This rate is different than the east direction, but has been accepted since
the value is within published literature values and rates can differ in
aquifers. However, the different values suggest different hydrogeological
characteristics between the east and south-southwest areas of the aquifer,
which has been recognized previously.
300 ug/l Average concentration where subsurface turns from anaerobic to aerobic zone
535 ft Distance from CBW-10 to MW-309 (proposed well)
33 ft Midpoint depth of saturated zone (estimated to be average source depth)
1140 ft Distance from 300 ug/l isoconcentration to CH2M-2
36, 3.6, 0.4 Contaminant Source Strength and Sensitivity Analysis (CDM 2008)
0.42 ft/d Contaminant Source Strength and Sensitivity Analysis (CDM 2008)
1.5 yrs Biodegradation rate needed to achieve the observed 8.5 ug/l TCE
Compound (direction)
Variables
C0
Y
Z
X
^ gw
Rf
«x
ay
«z
X
units
ug/l
feet
feet
feet
feet/day
unitless
feet
feet
feet
/day
TCE (east)
70
1050
33
520
0.14
3.5
36
3.6
0.4
0.00023
TCE (southwest)
160
535
33
1140
1.48
3.5
36
3.6
0.4
0.0013
Estimated TCE concentration at CH2M-2 with given values 4.9 ug/l
Estimated TCE concentration at CBW-11 with given values 4.8 ug/l
Therefore, on the east side, concentrations need to be decreased from 300 ug/l down to 70 ug/l, a reduction of 80%
and on the south-southwest side, concentrations need to decrease from 300 ug/l down to 160 ug/l, a reduction of 50%.
As reported by The EPA Center for Subsurface Modeling Support (CSMoS): CSMoS acknowledges that the Domenico-based models are approximate analytical
solutions of the advective-dispersive solute transport equation; therefore, they could generate an error for a given set of input parameters when compared with
the exact solutions. The error is largely sensitive to high values of longitudinal dispersivity (Srinivasan et al., 2007 and West et al., 2007). However, CSMoS
noticed that the error is insignificant when longitudinal dispersion is reasonably low (see Figures 2b and 5b of Srinivasan et al., 2007). Furthermore, longitudinal
dispersivity is a calibration parameter, not a parameter that is measured in the field, in real-world modeling applications. Therefore, CSMoS believes that the
Domenico-based models in their current forms are reasonable for screening level tools.
-------
Appendix E
Screening of Technologies and
Process Options
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
No Action
No Action
No Action
No action is
performed at the
site.
Not effective, but required
for consideration by the
NCP as a baseline for
comparison. Unlikely to be
acceptable due to the
level of contaminants on
site.
Easily implemented
None
Y
Y
Institutional
Controls
Institutional
Controls
Deed
Restrictions
Restricts land use
at the site.
Effective in limiting future
development of the site.
However, this process
alone would not eliminate
the potential for exposure
to contaminants.
Easily implemented
Low
Y
Y
Deed Notice
Provides
information on a
parcel.
Effective for relaying
information about a
property.
Easily implemented
Low
Y
Y
Zoning
Limits use of a
property.
Effective if enforced.
Moderately difficult
to implement since
it requires the
cooperation of the
municipality
Low
Y
Y
Containment
Capping
Asphalt Cap
Pave area to
prevent exposure
to contaminated
materials and limit
water infiltration.
Limits contact with
contaminated materials in
shallow soil and minimizes
water infiltration into
subsurface, with the use
of a relatively thin cap
construction.
Easily implemented
Low
Y
Y
CDM
Well 12A Final FFS April 2009
Page 1 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Containment
(continued)
Capping
(continued)
Clay Cap
Uses a layer of clay
to prevent
exposure to
contaminated
materials and limit
water infiltration.
Limits contact with
contaminated materials in
shallow soil and minimizes
water infiltration into
subsurface..
Moderately difficult
to implement given
current site
development.
Moderate
N
N
Geomembrane
Cap
Uses textile
material and
associated sub-
base and topsoil
layers to prevent
exposure to
contaminated
materials and limit
water infiltration.
Limits contact with
contaminated materials in
shallow soil and minimizes
water infiltration into
subsurface, with the use
of a relatively thin cap
construction.
Moderately difficult
to implement given
current site
development.
Moderate
N
N
Soil/Crushed
Concrete Cap
Uses a layer of soil
or crushed
concrete to limit
exposure to
contaminated
materials.
Limits contact with
contaminated materials in
shallow soil. Would not
prevent water infiltration
into the subsurface.
Moderately difficult
to implement given
current site
development.
Low
N
N
CDM
Well 12A Final FFS April 2009
Page 2 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Removal
Excavation
Excavation
Excavation of
contaminated soil
using typical
construction
equipment
Effective technique for
removing contaminated
soil and/or filter cake from
the site
Easily implemented
with standard earth
moving equipment
and/or hand tools
for filter cake and
shallow impacted
soils. Difficult to
implement for soils
beneath existing
buildings and below
the water table.
Low
(shallow)
to
High
(deep)
Y
N
Consolidation
Consolidation
Process of moving
materials from
various areas of the
site in order to
reduce the area to
be capped or
contained
Effective as a means of
reducing the area to be
capped. Minimal
additional benefit given
the limited unpaved area.
Easily implemented
with standard earth
moving equipment
for filter cake and
shallow impacted
soils. Difficult to
implement for soils
beneath existing
buildings and below
the water table.
Low to
Moderate
N
N
Treatment
Thermal
In-situ
Vitrification
A high temperature
process that melts
contaminated soil
in-situ, forming an
unleachable
monolith.
Effective in destroying
organic compounds. Off-
gas treatment may be
necessary to capture any
organics that are
vaporized during
treatment. Saturated soil
may lead to higher costs.
Relatively difficult
to implement due to
limited availability
of specialized
equipment and
operators
High
N
N
CDM
Well 12A Final FFS April 2009
Page 3 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Treatment
(continued)
Thermal
(continued)
In-situ Steam
Injection
Injection of steam
heats the soil and
groundwater and
enhances the
release of
contaminants from
the soil matrix by
decreasing
viscosity and
accelerating
volatilization.
Very effective in
mobilizing residual
DNAPL for collection and
treatment. Requires
vapor-phase or dual-
phase extraction and
treatment.
Relatively easy to
implement if size of
treatment zone is
limited. Can be
applied under
roads and existing
buildings. Similar to
ERH; can use in
high groundwater
flux if ERH not
implementable
Moderate
to High
N
N
In-situ
Electrical
Resistance
Heating
Uses arrays of
electrodes to apply
electrical current to
the subsurface.
Heat generated by
electrical resistance
in the soil creates
steam in-situ and
works similarly to
steam injection.
Very effective in
mobilizing residual
DNAPL for collection and
treatment. Requires
vapor-phase or dual-
phase extraction and
treatment.
Relatively easy to
implement if size of
treatment zone is
limited. Can be
applied under
roads and existing
buildings.
Groundwater flux
high, but
appropriate
Moderate
to High
N
Y
Exsitu
Incineration
High temperature
(2000 °F) burning
of soil that destroys
organic materials.
Can be conducted
either on site or off
site.
Very effective in
destroying organics.
Treated soil would be
backfilled or disposed
following incineration.
Anticipate difficulty
obtaining local
acceptance to site
an incinerator for
onsite treatment,
while offsite
treatment would be
readily
implementable.
Very High
N
N
CDM
Well 12A Final FFS April 2009
Page 4 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Treatment
(continued)
Thermal
(continued)
Low
Temperature
Thermal
Desorption
Low temperature
(300-600 °C)
process that
volatilizes organic
materials, which
are captured and
processed in an
offgas treatment
system or recycled.
Effective in treating
organics. Off-gas
treatment may be
necessary to capture any
organics that are
vaporized during
treatment.
Moderately difficult
to implement.
Moderate
N
N
Biological
In-situ
Bioremediation
Uses injection of an
electron donor and
nutrients to
stimulate
indigenous
bacteria.
Most effective on
dissolved-phase organics.
Recent studies show that
it can be effective in
source areas with residual
NAPL as well. Difficult to
non-applicable in vadose
zone
Relatively easy to
implement using
readily available
equipment.
Amendment
delivery can be
challenging in
heterogeneous
formations.
Moderate
N
N
Ex-situ
Bioremediation
Employs the
construction of
biological treatment
cells to break down
organic material.
Effective in treating
organics
Slightly difficult to
implement, due to
area required for
construction of
treatment cells.
Building limits
accessibility
Moderate
N
N
CDM
Well 12A Final FFS April 2009
Page 5 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Physical
In-situ Soil
Vapor
Extraction
Establishes a
vacuum in vadose
zone to volatilize
and extract VOCs
from soil.
Effective for removing
volatiles from vadose
zone. Limited
effectiveness below the
water table as a stand-
alone remedy, but may be
used in conjunction with
other remedies to recover
vapor phase (ERH and air
sparge) contaminants.
May reduce effectiveness
of anaerobic degradation.
Was very effective on
west side of Time Oil
building
Relatively easy to
implement.
Moderate
Y
Y
Treatment
(continued)
Physical
(continued)
In-situ Soil
Flushing
Process that injects
water/surfactants
into the subsurface
soil. Requires use
of extraction wells
or trenches to
capture
contaminants in the
groundwater.
Effective for removing
some contaminants from
soil, but may lead to
increased chance of
mobilizing contaminants
into groundwater. Not as
effective when soil
contains moderate to high
clay content.
Somewhat difficult
to implement due to
specialized
equipment required
and permitting
concerns.
Moderate
N
N
CDM
Well 12A Final FFS April 2009
Page 6 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Chemical
In-situ
Chemical
Oxidation
An oxidizing agent
(e.g., hydrogen
peroxide, Fenton's
Reagent,
potassium
permanganate,
persulfate, or
ozone) is injected
into the subsurface.
Organic
compounds are
destroyed upon
reaction with the
oxidant.
Effective organic
destruction if adequate
contact between reagents
and contaminants occurs.
Can adversely impact
anaerobic degradation in
source area.
Relatively easy to
implement using
readily available
equipment.
Delivery can be
challenging in
heterogeneous
formations.
Administrative
difficulties can be
anticipated,
including injection
permits for
reagents.
Moderate
to High
N
N
Disposal
Disposal
Offsite
Disposal
Disposal of material
(treated or
untreated) at an
offsite permitted
facility.
Effective as means of
minimizing exposure to
contaminants and
eliminating pathway for
transport of contaminants
to groundwater.
Offsite disposal is
relatively easy to
implement, but may
require treatment
prior to disposal to
meet LDRs.
High
Y
N
Disposal
(continued)
Disposal
(continued)
Onsite
Engineered
Cell
An engineered
waste cell that is
constructed onsite
with a bottom liner
and cover system
to receive treated
or untreated
material.
Effective as means of
minimizing exposure to
contaminants and
eliminating pathway for
transport of contaminants
to groundwater.
Requires significant
contaminated
materials handling.
May be difficult to
implement due to
long-term land use
issues and can
result in higher final
site elevation due
to liner and cover
system.
High
N
N
CDM
Well 12A Final FFS April 2009
Page 7 of 8
-------
Appendix E Table 1 of 2
Screening of Technologies and Process Options Applicable to Soil
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained
for Filter
Cake and
Shallow
Soils
Retained
for Deep
Vadose
Zone and
Upper
Saturated
Soils
Backfill
Disposal of treated
material onsite.
Effective method of
disposing of treated soil
provided MTCA levels are
met.
Relatively easy to
implement provided
that material has
been treated to
regulatory levels.
Low
N
N
CDM
Well 12A Final FFS April 2009
Page 8 of 8
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
No Action
No Action
No Action
No action is
performed at
the site.
Not effective,
but required for
consideration
by the NCP as
a baseline for
comparison.
Unlikely to be
acceptable due
to the level of
contaminants
on site.
Easily
implemented
None
Y
Y
Institutional
Controls
Institutional
Controls
Deed
Restrictions
Restricts land
use at the site.
Effective in
limiting future
development of
the site.
However, this
process alone
would not
eliminate the
potential for
exposure to
contaminants.
Easily
implemented
Low
Y
Y
Deed
Notice
Provides
information on
a parcel.
Effective for
relaying
information
about a
property.
Easily
implemented
Low
Y
Y
Zoning
Limits use of a
property.
Effective if
enforced.
Moderately
difficult to
implement since
it requires the
cooperation of
the municipality
Low
Y
Y
CDM
Well 12A Final FFS April 2009
Page 1 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Retained for
Retained for
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
High
Concentration
Low
Concentration
Groundwater
Groundwater
Monitored
Monitored
Monitored
Natural
Can be
Easily
Low
N
N
Natural
Natural
Natural
destructive
effective where
implemented
Attenuation
Attenuation
Attenuation
(biodegradation
and chemical
reactions) and
nondestructive
mechanisms
(dilution,
dispersion,
volatilization,
and adsorption)
that reduce
contaminant
levels.
natural
conditions
promote
contaminant
degradation
Containment
Vertical
Barrier
Slurry Wall
A subsurface
barrier
consisting of a
trench filled
with a slurry of
either a soil/
bentonite
mixture or a
cement/
bentonite
mixture, which
provides a
physical barrier
to the
contaminated
groundwater.
May require
groundwater
extraction to
maintain
hydraulic
control.
Slurry wall
barrier is
effective in
preventing
additional
groundwater
contamination
from migrating
offsite or for
diverting
uncontaminated
groundwater
around a
contaminant
source. Limited
effectiveness if
confining layer
is not
continuous
below source
area.
Difficult to
implement due to
depth. Slurry wall
would be keyed
into confining
layer present at
the site.
High
N
N
CDM
Well 12A Final FFS April 2009
Page 2 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Containment
Vertical
Grout
A grout curtain
Grout curtain
Grout curtains
Moderate to
N
N
(continued)
Barrier
Curtain
is a solid, low-
barrier is
are not subject to
High
(continued)
permeability
effective in
the depth
subsurface
preventing
limitations of
vertical barrier
additional
other vertical
formed by
groundwater
barriers
injecting grout
contamination
considered, but it
(e.g., Portland
from migrating
may be difficult to
cement)
offsite or for
verify whether or
through well
diverting
not a continuous
points or an
uncontaminated
barrier has been
injection auger.
groundwater
formed.
May require
around a
groundwater
contaminant
extraction to
source. Limited
maintain
effectiveness if
hydraulic
confining layer
control.
is not
continuous
below source
area.
CDM
Well 12A Final FFS April 2009
Page 3 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Retained for
Retained for
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
High
Concentration
Low
Concentration
Groundwater
Groundwater
Collection/
Extraction
Extraction
Use of wells to
An existing
Readily
Moderate to
Y
N
Extraction
Wells
extract
groundwater
implementable.
High
contaminated
extraction and
Would require
long-term use of
groundwater
from the
treatment
system has
been operating
aquifer or to
extraction wells.
create
onsite for 20
hydraulic
years. If
barriers,
enhancements
preventing
are made, the
contaminated
use of
groundwater
extraction wells
from migrating
is expected to
offsite.
be somewhat
effective for
collection of
contaminated
groundwater.
The presence
of residual
NAPL will
provide a
continuing
source of
groundwater
contamination,
limiting
extraction
effectiveness
for long-term
source removal.
CDM
Well 12A Final FFS April 2009
Page 4 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Collection/
Enhanced
Surfactant
Injection of
Increases the
Moderately easy
Moderate to
N
N
Extraction
Extraction
Flushing
surfactant(s)
movement of
to implement.
High
(continued)
into a zone of
viscous and
Can potentially
contaminated
low-solubility
reduce pump-
groundwater to
organic
and-treat times,
mobilize and
contaminants.
but administrative
solubilize
Effective in
difficulties are
contaminants,
removing
anticipated.
followed by
organics from
Addition of
downgradient
the subsurface
surfactant(s) may
extraction of
when used in
require an EPA
the
conjunction with
Underground
contaminated
collection
Injection Control
groundwater
methods such
(UIC) permit.
and surfactant
as extraction
mixture.
wells.
CDM
Well 12A Final FFS April 2009
Page 5 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Retained for
Retained for
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
High
Concentration
Low
Concentration
Groundwater
Groundwater
Collection/
Enhanced
In-situ
Application of
Possibly
Relatively easy to
Moderate to
N
N
Extraction
Extraction
Pressure
mechanical
effective for
implement, but
High
(continued)
(continued)
Pulse
Technology
vibration in
injection wells
through the use
of hyd raulically
or
pneumatically
actuated
sudden
movement of a
displacement
piston to create
a large impulse
and mixing
zone.
enhancing
pump and
treatment
systems which
have limitations
due to
presence of
residual NAPL.
May be applied
in conjunction
with surfactant
flushing to
improve and
control
dispersal of the
surfactant(s) in
low
permeability
conditions. Full-
scale
implementation
has not yet
been applied.
requires
specialized
equipment.
CDM
Well 12A Final FFS April 2009
Page 6 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Treatment
Biological
In-situ Bio-
remediation
Uses injection
of an electron
donor and
nutrients to
stimulate
indigenous
bacteria.
Significant
reductive
dechlorination
is or has been
occurring
naturally in the
primarily
anaerobic
source area
and there is
evidence to
support TCE
degradation
aerobic zones
on the
periphery of the
primary plume.
Enhancing
these natural
processes is
likely to be very
effective.
Relatively easy to
implement using
readily available
equipment.
Remedial
delivery can be
challenging in
heterogeneous
formations.
Moderate
Y
N
CDM
Well 12A Final FFS April 2009
Page 7 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Treatment
Physical/
In-Situ
A containment
Effective in
Difficult to
Moderate to
N
N
(continued)
Chemical
Permeable
wall
treating
implement due to
high
(In-situ)
Reactive
constructed
contaminated
depth
Barrier
perpendicular
groundwater
to the flow path
released from a
of a plume that
NAPL source
directs the
area, but are
contaminants
not effective for
to move
treating residual
through the
NAPL material.
reactive gates
Treatment
(treatment
zones in the
weir) for
barrier, such as
treatment.
zero valent iron
Contaminants
or carbon
are removed
media can be
through
used to treat
reaction with
contaminants
the permeable
that move
reactive
through the
medium.
zones.
CDM
Well 12A Final FFS April 2009
Page 8 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Treatment
Physical/
In-situ
An oxidizing
Effective
Relatively easy to
Moderate to
N
N
(continued)
Chemical
Chemical
agent (e.g.,
organic
implement using
High
(In-situ)
Oxidation
hydrogen
destruction if
readily available
(continued)
peroxide,
adequate
equipment.
Fenton's
contact
Chemical delivery
Reagent,
between
can be
potassium
reagents and
challenging in
permanganate,
contaminants
heterogeneous
persulfate, or
occurs. Less
formations.
ozone) is
effective at
Administrative
injected into
treating free
difficulties can be
the subsurface.
product NAPL
anticipated,
Organic
as large
including injection
compounds are
quantities of
permits for
destroyed upon
oxidant would
reagents.
reaction with
be required.
the oxidant.
One of few
treatment
technologies
applicable to
1,4-dioxane.
Can interfere
with anaerobic
degradation
processes.
CDM
Well 12A Final FFS April 2009
Page 9 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Treatment
Physical/
Air
Air sparging
Effective for
Relatively easy to
Moderate
Y
N
(continued)
Chemical
Sparging
involves the
volatile
implement. Well
(In-situ)
injection of air
organics.
locations would
(continued)
or oxygen into
Oxygen added
be limited by
the
to the
existing
contaminated
contaminated
development.
aquifer.
groundwater
Injected air
and vadose-
strips volatile
zone soils also
and
can enhance
semivolatile
aerobic
organic
biodegradation
contaminants
of contaminants
in-situ and
below and
helps to flush
above the water
the
table, but will
contaminants
have adverse
into the
effects to
unsaturated
anaerobic
zone. SVE is
degradation. Air
usually is
stripping could
implemented in
be used
conjunction
effectively in
with air
the source area
sparging to
groundwater
remove the
plume or as a
vapor-phase
barrier between
contamination
the Time Oil
from the
property and
vadose zone
Well 12A.
and to mitigate
Could increase
impacts to
exposure to
surface
surface
receptors.
receptors if not
implemented in
conjunction with
SVE.
CDM
Well 12A Final FFS April 2009
Page 10 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Retained for
Retained for
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
High
Concentration
Low
Concentration
Groundwater
Groundwater
Treatment
Physical/
Carbon
Extracted
Effective
Readily
Low
Y
N
(continued)
Chemical
(Ex-Situ)
Adsorbtion
groundwater or
off-gas is
pumped
through a
reactor vessel
containing
granular
activated
carbon (GAC)
to which
contaminants
adsorb and are
removed.
removal of most
organics, but is
susceptible to
biological and
inorganic
fouling. Not
effective in
removing 1,4-
dioxane. Very
limited capacity
for adsorption
of vinyl chloride
implementable.
Existing GETS
system currently
uses liquid-phase
carbon
adsorbtion.
Air
Mass transfer
Effective
Readily
Low
Y
Y
Stripping
of volatile
contaminants
from water to
air by
increasing
surface area of
the
groundwater
exposed to air.
removal of most
organics, but is
susceptible to
biological and
inorganic
fouling. Not
effective in
removing 1,4-
dioxane.
implementable.
Could be added
to existing GETS
system to
improve
performance and
possibly reduce
O&M costs. Air
stripping currently
used at Well 12A
CDM
Well 12A Final FFS April 2009
Page 11 of 12
-------
Appendix E Table 2 of 2
Screening of Technologies and Process Options Applicable to Groundwater
General
Response
Action
Technology
Type
Process
Option
Description
Effectiveness
Implementability
Cost
Retained for
High
Concentration
Groundwater
Retained for
Low
Concentration
Groundwater
Treatment
(continued)
Physical/
Chemical
(Ex-Situ)
Ex-Situ
Advanced
Oxidation
Advanced
Oxidation
Processes
including
ultraviolet (UV)
radiation,
ozone, and/or
hydrogen
peroxide are
used to destroy
organic
contaminants
as water flows
into a treatment
tank.
Effective
treatment of
most organics.
One of few
treatment
technologies
applicable to
1,4-dioxane.
Relatively easy to
implement using
commercially
available systems
Moderate to
High
N
N
Disposal
Disposal
Offsite
Disposal
Disposal of
treated water
or treatment
waste residuals
to offsite facility
by truck or
storm/sanitary
sewer.
Effective
method for
disposing of
waste residuals
and treated
water. Water
may require
pre-treatment to
meet the facility
acceptance
requirements.
Readily
implementable.
Existing GETS
system currently
discharges to
storm sewer.
Low to
Moderate
Y
N
Disposal
Disposal
(continued)
Onsite
Disposal
Disposal of
treated water
onsite into the
subsurface
using injection
wells or an
infiltration
gallery.
Effectiveness
could be limited
by biofouling of
injection wells
an/or infiltration
galleries.
Moderately easy
to implement, but
may require
ongoing
maintenance.
Moderate
N
N
CDM
Well 12A Final FFS April 2009
Page 12 of 12
-------
Appendix F
Cost Estimates
-------
Appendix F
Cost Estimates
Appendix F provides supporting information for one of the EPA Primary Balancing Criteria,
Cost. An estimate of the cost for each alternative is determined so that the cost can be compared
to the level of protectiveness that each alternative provides. The typical cost estimate made
during the FFS is intended to provide an accuracy of +50 percent to -30 percent, as discussed in
the EPA RI/FS guidance document. The types of costs that are assessed include the capital
costs, operation and maintenance (O&M) costs, and present worth. For the present worth
analysis, a 7% discount rate was used, and the evaluation period is 30 years, unless otherwise
stated.
Several resources were accessed to develop cost estimates for the FFS in addition to general
engineering experience. Main components of the alternatives are identified below and the
resources that were used to develop the costs are listed.
Treatment Zone with
Alternative Components/Items
Resource
Filter Cake and Shallow Impacted Soil
Placing Asphalt Cap (items a through h)
Means CostWorks Version 11.0 release update
2008 Cost Data
Excavation, disposal and backfill (Items a through i)
Means CostWorks Version 11.0 release update
2008 Cost Data
Deep Vadose Zone and Upper Saturated Soil
Insitu Thermal Remediation (items a through n)
Estimate from Thermal Remediation Services, Inc.
received October 31, 2008
High Concentration Groundwater
Groundwater Extraction and Treatment O&M
(items a through d)
Estimate from Chuck Hinds of Washington State
Department of Ecology (current system operators)
received October 30, 2008
Mass Flux Measurements
(items a and b)
Estimates based on values for similar work
provided in Final East Gate Disposal Yard Thermal
Remediation Performance Assessment After Action
Report (USACE, et al 2008)
Enhanced Anaerobic Bioremediation
(items a through e)
Iceland Coin Laundry Superfund Site FS by CDM
Air Sparge/Soil Vapor Extraction
(items a through n)
Vienna PCE Superfund Site FS by CDM (also SVE
well installation, sparge well installation, blower and
control panel were checked in Means CostWorks
Version 11.0 release update 2008 Cost Data)
Low Concentration Groundwater
Well 12A Stripping Towers O&M
Estimate based on incurred costs received from
Tacoma Water on October 14, 2008
-------
Cost Estimate for Alternative FC2
Filter Cake and Shallow Impacted Soil
Institutional Controls
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Institutional Controls
(a) Deed restrictions
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$20,000
LS
LS
$20,000
$30,000
$64,740
Subtotal (1)
$30,000
$64,740
CONSTRUCTION SUBTOTAL
$20,000
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$400
$400
$800
$8,000
CONSTRUCTION TOTAL | | |
$29,600
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$296
$444
$296
TOTAL CAPITAL COSTS | | |
$30,636
OPERATION & MAINTENANCE SUBTOTAL | | |
$30,000
$64,740
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$1,500
$7,500
$3,237
$16,185
TOTAL ESTIMATED COSTS | | |
$30,636
$39,000
$84,162
NET PRESENT WORTH $114,798
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative FC3
Filter Cake and Shallow Impacted Soil
Placing Asphalt Cap
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Placing asphalt cap
(a) Mobilization
(b) Crushed stone base course
(c) Bituminous concrete base course
(d) Wear course
(e) Vibratory roller
(f) Asphalt transport (in truck deliveries)
(g) Health and safety
(h) Erosion control
1
11,350
230
115
2
20
1
1
$90,000
$12
$59
$65
$672
$330
$50,000
$5,000
LS
SF
TON
TON
WK
TRK
LS
LS
$90,000
$136,768
$13,570
$7,475
$1,344
$6,600
$50,000
$5,000
Subtotal (1)
$310,757
(2) Long-term Monitoring (30 years)
(a) Develop Sampling Plan
(b) Annual Sampling (4 wells)
(1) sample collection
(2) sample analysis
1
1
4
$15,000
$6,000
$500
LS
event
EA
$15,000
$6,000
$2,000
$74,454
$24,818
Subtotal (2)
$15,000
$8,000
$99,272
(3) O&M of Cap (one event every 5 years for 30 years)
(4) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$15,000
$30,000
LS
LS
$5,000
$15,000
$30,000
$10,790
$186,136
$64,740
Subtotal (3)
$50,000
$261,666
CONSTRUCTION SUBTOTAL
$325,757
Contractor Submittals, H&S, and Construction QA/QC 10% of Construction Subtotal
Contractor Overhead 15% of Construction Subtotal
Contractor Profit 10% of Construction Subtotal
Contingency 40% of Construction Subtotal
$32,576
$48,863
$32,576
$130,303
CONSTRUCTION TOTAL | | |
$570,074
Project Management 10% of Construction Total
Engineering 15% of Construction Total
Services During Construction 15% of Construction Total
$57,007
$85,511
$85,511
TOTAL CAPITAL COSTS | | |
$798,103
OPERATION & MAINTENANCE SUBTOTAL | | |
$58,000
$360,938
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative FC3
Filter Cake and Shallow Impacted Soil
Placing Asphalt Cap
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
O&M Project Management and Support
O&M Contingency
5% of O&M Subtotal
25% of O&M Subtotal
$2,900
$14,500
$18,047
$90,234
TOTAL ESTIMATED COSTS | | |
$798,103
$75,400
$469,219
NET PRESENT WORTH
$1,267,323
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative FC4
Filter Cake and Shallow Impacted Soil
Excavation and Offsite Disposal
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Excavation
(a) Mobilization
(b) Excavation
(c) Borrow material transportation
(d) Backfill excavation
(e) Base course to 6 in deep
(f) 2A gravel furnish and deliver
(g) Health and safety
(h) Offsite disposal at Subtitle D landfill (in truck deliveries)
(i) Transportation of material to disposal
1
4,200
5,250
5,250
11,350
400
1
360
6,400
$90,000
$2
$13
$34
$12
$10
$50,000
$330
$45
LS
BCY
ECY
ECY
SF
TON
LS
TRK
TON
$90,000
$8,400
$68,250
$178,500
$136,768
$4,040
$50,000
$118,800
$288,000
Subtotal (1)
$942,758
(2) Long-term Monitoring (30 years)
(a) Develop Sampling Plan
(b) Annual Sampling (4 wells)
(1) sample collection
(2) sample analysis
1
1
4
$15,000
$6,000
$500
LS
event
EA
$15,000
$6,000
$2,000
$74,454
$24,818
Subtotal (2)
$15,000
$8,000
$99,272
(3) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$15,000
$30,000
LS
LS
$15,000
$30,000
$186,136
$64,740
Subtotal (3)
$45,000
$250,876
CONSTRUCTION SUBTOTAL
$957,758
Contractor Submittals, H&S, and Construction QA/QC 10% of Construction Subtotal
Contractor Overhead 15% of Construction Subtotal
Contractor Profit 10% of Construction Subtotal
Contingency 40% of Construction Subtotal
$95,776
$143,664
$95,776
$383,103
CONSTRUCTION TOTAL | | |
$1,676,076
Project Management 10% of Construction Total*
Engineering 15% of Construction Total*
Services During Construction 15% of Construction Total*
$167,608
$251,411
$251,411
TOTAL CAPITAL COSTS | | |
$2,346,506
OPERATION & MAINTENANCE SUBTOTAL | | |
$53,000
$350,148
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative FC4
Filter Cake and Shallow Impacted Soil
Excavation and Offsite Disposal
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
O&M Project Management and Support
O&M Contingency
5% of O&M Subtotal
25% of O&M Subtotal
$2,650
$13,250
$17,507
$87,537
TOTAL ESTIMATED COSTS | | |
$2,346,506
$68,900
$455,192
NET PRESENT WORTH
$2,801,698
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative SG2
Deep Vadose Soil and Upper Saturated Soil East of Time Oil Building
Institutional Controls
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Institutional Controls
(a) Deed restrictions
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$30,000
LS
LS
$20,000
$30,000
$64,740
Subtotal (1)
$30,000
$64,740
CONSTRUCTION SUBTOTAL
$20,000
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$400
$400
$800
$8,000
CONSTRUCTION TOTAL | | |
$29,600
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$296
$444
$296
TOTAL CAPITAL COSTS | | |
$30,636
OPERATION & MAINTENANCE SUBTOTAL | | |
$30,000
$64,740
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$1,500
$7,500
$3,237
$16,185
TOTAL ESTIMATED COSTS | | |
$30,636
$39,000
$84,162
NET PRESENT WORTH $114,798
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative SG3
Deep Vadose Soil and Upper Saturated Soil East of Time Oil Building
Insitu Thermal Remediation
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Insitu Thermal Remediation
(a) Mobilization
1
$381,000
LS
$381,000
(b) Design, work plans, permits
1
$80,000
LS
$80,000
(c) Subsurface Installation
1
$169,000
LS
$169,000
(d) Surface Installation and Startup
1
$304,000
LS
$304,000
(e) Remediation System Operation
1
$472,000
LS
$472,000
(f) Trenching and Restoration (50% below grade):
1
$43,000
LS
$43,000
(g) Drilling and Soil Sampling:
1
$304,000
LS
$304,000
(h) Drill Cuttings and Waste Disposal:
1
$35,000
LS
$35,000
(i) Electrical Utility Connection to PCU:
1
$30,000
LS
$30,000
(j) Electrical Energy Usage:
1
$294,000
LS
$294,000
(k) Carbon Usage, Transportation & Regeneration:
1
$13,000
LS
$13,000
(1) Water/ Condensate Disposal:
1
$1,000
LS
$1,000
(m) Other Operational Costs:
1
$22,000
LS
$22,000
(n) Demobilization and final report
1
$94,000
LS
$94,000
Subtotal (1)
$2,242,000
(2) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
1
$20,000
LS
$20,000
(b) Annual Sampling (10 wells, years 1 through 6)
(1) sample collection
1
$10,000
event
$10,000
$47,665
(2) sample analysis
10
$500
EA
$5,000
$23,833
Subtotal (2)
$20,000
$15,000
$71,498
(3) Reporting
(a) Review data and prepare annual reports
1
$20,000
LS
$20,000
$248,181
(b) 5-year review (every 5 years for 30 years)
1
$50,000
LS
$50,000
$107,891
Subtotal (3)
$70,000
$356,072
CONSTRUCTION SUBTOTAL
$2,262,000
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative SG3
Deep Vadose Soil and Upper Saturated Soil East of Time Oil Building
Insitu Thermal Remediation
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
Contractor Submittals, H&S, and Construction QA/QC 1% of Construction Subtotal*
Contractor Overhead 1.5% of Construction Subtotal*
Contractor Profit 1% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$22,620
$33,930
$22,620
$904,800
CONSTRUCTION TOTAL | | |
$3,245,970
Project Management 10% of Construction Total
Engineering 1.5% of Construction Total*
Services During Construction 15% of Construction Total
$324,597
$48,690
$486,896
TOTAL CAPITAL COSTS | | |
$4,106,152
OPERATION & MAINTENANCE SUBTOTAL | | |
$85,000
$427,570
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$4,250
$21,250
$21,378
$106,892
TOTAL ESTIMATED COSTS | | |
$4,106,152
$110,500
$555,841
NET PRESENT WORTH $4,661,993
* Items are less than typical, since costs are included with contractor estimate which is in Subtotal (1)
Cost estimate is based on the electrical resistance heating method
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG2
High Concentration Groundwater
Institutional Controls
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Institutional Controls
(a) Deed restrictions
(b) 5-year review (every 5 years for 30 years)
1
1
$40,000
$40,000
LS
LS
$40,000
$40,000
$86,320
Subtotal (1)
$40,000
$86,320
CONSTRUCTION SUBTOTAL
$40,000
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$800
$800
$1,600
$16,000
CONSTRUCTION TOTAL | | |
$59,200
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$592
$888
$592
TOTAL CAPITAL COSTS | | |
$61,272
OPERATION & MAINTENANCE SUBTOTAL | | |
$40,000
$86,320
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$2,000
$10,000
$4,316
$21,580
TOTAL ESTIMATED COSTS | | |
$61,272
$52,000
$112,216
NET PRESENT WORTH $173,488
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG3
High Concentration Groundwater
Groundwater Extraction and Treatment System Operation and Maintenance
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Groundwater Extraction and Treatment O&M (30 years)
(a) Carbon changes
(b) Supplies and repairs
(c) Utilities
(d) Labor
3
1
1
1
$42,000
$5,000
$10,000
$45,000
YR
YR
YR
YR
$126,000
$5,000
$10,000
$45,000
$1,563,539
$62,045
$124,090
$558,407
Subtotal (1)
$186,000
$2,308,082
(2) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
(b) Annual Sampling (10 wells)
(1) sample collection
(2) sample analysis
1
1
10
$20,000
$10,000
$500
LS
event
EA
$20,000
$10,000
$5,000
$124,090
$62,045
Subtotal (2)
$20,000
$15,000
$186,136
(3) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$40,000
LS
LS
$20,000
$40,000
$248,181
$86,320
Subtotal (3)
$60,000
$334,501
CONSTRUCTION SUBTOTAL
$20,000
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$400
$400
$800
$8,000
CONSTRUCTION TOTAL | | |
$29,600
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$296
$444
$296
TOTAL CAPITAL COSTS | | |
$30,636
CDM
Well 12A Final FFS April 2009
-------
High Concentration Groundwater
Groundwater Extraction and Treatment System Operation and Maintenance
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
OPERATION & MAINTENANCE SUBTOTAL
$261,000
$2,828,718
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$13,050
$65,250
$141,436
$707,180
TOTAL ESTIMATED COSTS | | |
$30,636
$339,300
$3,677,334
NET PRESENT WORTH $3,707,970
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG4
High Concentration Groundwater
Enhanced Anaerobic Bioremediation
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Enhanced Anaerobic Bioremediation
(a) Mobilization
(b) Injection Well Installation
(c) MW Installation
(d) Amendment Injection (2 rounds)
(e) Pilot-scale treatability test
(f) Confirmation Sampling (pre-, and 8 qtrly events)
(1) sample collection
(2) sample analysis (10 monitoring wells)
1
34
8
2
1
9
90
$50,000
$7,980
$14,110
$395,580
$50,000
$25,000
$800
LS
EA
EA
RD
LS
event
sample
$50,000
$271,320
$112,880
$791,160
$50,000
$225,000
$72,000
Subtotal (1)
$1,572,360
(2) Mass Flux Measurement (5 events at 12 wells over 6 years)
(a) Flux work plan development
(a) Flux device installation/ removal
(b) Sample analysis
1
1
12
$10,000
$8,000
$1,000
LS
EA
EA
$10,000
$8,000
$12,000
$38,132
$57,198
Subtotal (2)
$10,000
$20,000
$95,331
(3) Groundwater Extraction and Treatment O&M (5 years)
1
$209,000
YR
$209,000
$856,941
Subtotal (3)
$209,000
$856,941
(4) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
(b) Annual Sampling (10 wells, years 1 through 6)
(1) sample collection
(2) sample analysis
1
1
10
$20,000
$10,000
$500
LS
event
EA
$20,000
$10,000
$5,000
$47,665
$23,833
Subtotal (4)
$20,000
$15,000
$71,498
(5) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$50,000
LS
LS
$20,000
$50,000
$248,181
$107,891
Subtotal (5)
$70,000
$356,072
CONSTRUCTION SUBTOTAL
$1,582,360
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG4
High Concentration Groundwater
Enhanced Anaerobic Bioremediation
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$31,647
$31,647
$63,294
$632,944
CONSTRUCTION TOTAL | | |
$2,341,893
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$23,419
$35,128
$23,419
TOTAL CAPITAL COSTS | | |
$2,423,859
OPERATION & MAINTENANCE SUBTOTAL | | |
$314,000
$1,379,842
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$15,700
$78,500
$68,992
$344,960
TOTAL ESTIMATED COSTS | | |
$2,423,859
$408,200
$1,793,795
NET PRESENT WORTH $4,217,654
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG5
High Concentration Groundwater
Enhanced Anaerobic Bioremediation with Air Sparging and Soil Vapor Extraction
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Enhanced Anaerobic Bioremediation
(a) Mobilization
1
$50,000
LS
$50,000
(b) Injection Well Installation
28
$7,980
EA
$223,440
(c) MW Installation
8
$14,110
EA
$112,880
(d) Amendment Injection (2 rounds)
2
$336,243
RD
$672,486
(e) Pilot-scale treatability test
1
$50,000
LS
$50,000
(f) Confirmation Sampling (pre-, and 8 qtrly events)
(1) sample collection
9
$25,000
event
$225,000
(2) sample analysis (10 monitoring wells)
90
$800
sample
$72,000
Subtotal (1)
$1,405,806
(2) In Situ Air Sparging and Soil Vapor Extraction
System Installation and 4 years of Operation
(a) Mobilization
1
$50,000
LS
$50,000
(b) Air sparging well installation
5
$18,110
EA
$90,550
(c) Soil Vapor Extraction Well installation
10
$4,000
EA
$40,000
(d) Site Services
4
$50,000
MO
$200,000
(e) Pilot Testing
1
$100,000
LS
$100,000
(I) Piping to Each Air Sparging/SVE Point
1,000
$50
LF
$50,000
(g) Building for Air Sparging/SVE Air Handling System
5,000
$25
SF
$125,000
(h) Air Blower
2
$4,100
EA
$8,200
(i) Control Panel
1
$5,000
EA
$5,000
(j) Gas Phase Carbon Adsorption
2
$12,000
EA
$24,000
(k) Installation and Incidentals (piping, electrical)
1.0
$37,200
EA
$37,200
(1) Treatment System Operator (20 hours/week)
1,040
$50
HR
$52,000
$176,135
(m) Carbon Media Replacement
1,000
$3
LB
$3,300
$11,178
(n) Utilities and Maintenance
1
$50,000
YR
$50,000
$169,361
Subtotal (2)
$729,950
$105,300
$356,673
(3) Mass Flux Measurement (5 events at 12 wells over 6 years)
(a) Flux work plan development
1
$10,000
LS
$10,000
(a) Flux device installation/ removal
1
$8,000
EA
$8,000
$38,132
(b) Sample analysis
12
$1,000
EA
$12,000
$57,198
Subtotal (3)
$10,000
$20,000
$95,331
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative HG5
High Concentration Groundwater
Enhanced Anaerobic Bioremediation with Air Sparging and Soil Vapor Extraction
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(4) Groundwater Extraction and Treatment O&M (5 years)
1
$209,000
YR
$209,000
$856,941
Subtotal (4)
$209,000
$856,941
(5) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
(b) Annual Sampling (10 wells, years 1 through 6)
(1) sample collection
(2) sample analysis
1
1
10
$20,000
$10,000
$500
LS
event
EA
$20,000
$10,000
$5,000
$47,665
$23,833
Subtotal (5)
$20,000
$15,000
$71,498
(6) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$50,000
LS
LS
$20,000
$50,000
$248,181
$107,891
Subtotal (6)
$70,000
$356,072
CONSTRUCTION SUBTOTAL
$1,415,806
Contractor Submittals, H&S, and Construction QA/QC 10% of Construction Subtotal
Contractor Overhead 15% of Construction Subtotal
Contractor Profit 10% of Construction Subtotal
Contingency 40% of Construction Subtotal
$141,581
$212,371
$141,581
$566,322
CONSTRUCTION TOTAL | | |
$2,477,661
Project Management 10% of Construction Total
Engineering 15% of Construction Total
Services During Construction 10% of Construction Total
$247,766
$371,649
$247,766
TOTAL CAPITAL COSTS | | |
$3,344,842
OPERATION & MAINTENANCE SUBTOTAL | | |
$419,300
$1,485,142
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$20,965
$104,825
$74,257
$371,285
TOTAL ESTIMATED COSTS | | |
$3,344,842
$545,090
$1,930,685
NET PRESENT WORTH $5,275,526
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative LG2
Low Concentration Groundwater
Welll2A Treatment Operation and Maintenance
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Well 12A Air Stripping Towers O&M (30 years)
(a) Supplies
(b) Utilities
(c) Labor
1
1
1
$500
$20,000
$2,500
YR
YR
YR
$500
$20,000
$2,500
$6,205
$248,181
$31,023
Subtotal (1)
$23,000
$285,408
(2) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
(b) Annual Sampling (4 wells)
(1) sample collection
(2) sample analysis
1
1
4
$20,000
$8,000
$500
LS
event
EA
$20,000
$8,000
$2,000
$99,272
$24,818
Subtotal (2)
$20,000
$10,000
$124,090
(3) Reporting
(a) Review data and prepare annual reports
(b) 5-year review (every 5 years for 30 years)
1
1
$20,000
$40,000
LS
LS
$20,000
$40,000
$248,181
$86,320
Subtotal (3)
$60,000
$334,501
CONSTRUCTION SUBTOTAL
$20,000
Contractor Submittals, H&S, and Construction QA/QC 2% of Construction Subtotal*
Contractor Overhead 2% of Construction Subtotal*
Contractor Profit 4% of Construction Subtotal*
Contingency 40% of Construction Subtotal
$400
$400
$800
$8,000
CONSTRUCTION TOTAL | | |
$29,600
Project Management 1% of Construction Total*
Engineering 1.5% of Construction Total*
Services During Construction 1% of Construction Total*
$296
$444
$296
TOTAL CAPITAL COSTS | | |
$30,636
CDM
Well 12A Final FFS April 2009
-------
Low Concentration Groundwater
Welll2A Treatment Operation and Maintenance
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
OPERATION & MAINTENANCE SUBTOTAL
$93,000
$743,999
O&M Project Management and Support 5% of O&M Subtotal
O&M Contingency 25% of O&M Subtotal
$4,650
$23,250
$37,200
$186,000
TOTAL ESTIMATED COSTS | | |
$30,636
$120,900
$967,199
NET PRESENT WORTH $997,835
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
CDM
Well 12A Final FFS April 2009
-------
Cost Estimate for Alternative LG2
Low Concentration Groundwater
Long Term Plume Monitoring Component
Item
Quantity
Unit Cost
Units
Capital Cost
O&M Cost
Annual
Present Worth
(1) Compliance Well Installation (4 Wells)
(a) Mobilization
(b) MW Installation
(c) IDW Management
1
4
1
$10,000
$18,000
$30,000
LS
EA
LS
$10,000
$72,000
$30,000
Subtotal (1)
$112,000
(2) Long-term Groundwater Monitoring
(a) Develop Sampling Plan
(b) Annually (20 wells, years 1 through 30)
(1) sample collection (assume existing wells will be used)
(2) sample analysis
1
1
20
$20,000
$10,000
$500
LS
event
EA
$20,000
$10,000
$10,000
$124,090
$124,090
Subtotal (2)
$20,000
$20,000
$248,181
(3) Institutional Controls
(a) Deed Restrictions
(b) Review Data and Prepare Reports (annually)
(c) 5-Year Review Reporting (every 5 years for 30 years)
1
1
1
$25,000
$20,000
$50,000
LS
EA
LS
$25,000
$20,000
$50,000
$248,181
$107,891
Subtotal (3)
$25,000
$70,000
$356,072
CONSTRUCTION SUBTOTAL
$157,000
$90,000
Contractor Submittals and H&S (included above) 0% of Construction Subtotal*
Contractor Overhead 15% of Construction Subtotal
Contractor Profit 10% of Construction Subtotal
Contingency 40% of Construction Subtotal
$0
$23,550
$15,700
$62,800
CONSTRUCTION TOTAL | | |
$259,050
Project Management 10% of Construction Total
Engineering 5% of Construction Total*
Services During Construction 5% of Construction Total*
$25,905
$12,953
$12,953
TOTAL CAPITAL COSTS | | |
$310,860
OPERATION & MAINTENANCE SUBTOTAL | | |
$110,000
$604,252
O&M Project Management and Support 5% of O & M Subtotal
O&M Contingency 25% of O & M Subtotal
$5,500
$27,500
$30,213
$151,063
TOTAL ESTIMATED COSTS | | |
$310,860
$143,000
$785,528
NET PRESENT WORTH
$1,096,388
* This percentage rate is lower than some other alternatives to more accurately reflect the costs that are estimated for the type of services associated with this alternative.
The monitoring costs on this sheet are for the aquifer which supplies water to Welll2A. Additional long term costs are presented in Item 2 of Welll2A Treatment Operation and
Maintenance, which are costs for monitoring at Welll2A.
CDM
Well 12A Final FFS April 2009
------- |