FOURTH FIVE-YEAR REVIEW REPORT FOR
COMMENCEMENT BAY -
SOUTH TACOMA CHANNEL SUPERFUND SITE
TACOMA, WASHINGTON
S7^,
s-
PREPARED BY
United States Army Corps of Engineers (USACE)
Seattle District
Seattle, Washington
Approved by; _ Date:
^/{C/l3
Cami Grandinetti. Remedial Cleanup Program
Manager
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Executive Summary
This document presents the fourth Five-Year Reviews (FYR) for the Commencement Bay, South
Tacoma Channel (STC) Superfund site in Tacoma, Washington. Although the STC was listed on the
NPL as a single site due to the proximity of three different problem areas in south Tacoma, the three
areas are distinctly different with separate problems, remedies, and approaches to protectiveness. The
three main project areas (Well 12A, South Tacoma Field (STF), Tacoma Landfill) were broken down
into the following Operable Units (OUs) within the STC:
• OU 1 - Well 12A/groundwater
• OU 2 - Well 12A Burlington Northern Soil Removal
• OU 3 - Well 12A Soils (Vapor Extraction System)
• OU 4 - South Tacoma Field (STF)
• OU 5 - Tacoma Landfill/cap
• OU 6 - Tacoma Landfill/groundwater
The FYR groups OUs by project area, with a separate section for each project area (Well 12A, STF,
Tacoma Landfill) that discusses the active OUs within that project area. Note the Burlington Northern
Soil Removal and Well 12A Soils/Vapor Extraction System were designated as OUs 2 and 3 for
administrative purposes, but are actually remedy components of the overall Well 12A remedy, which
is designated as OU1. This FYR addresses the entire Well 12A project area including any remaining
exposures in all the OUs, but OUs 2 and 3 are not mentioned further in this document. Figure ES-1
shows the location of the three project areas within the STC Superfund site.
Five-Year Review summaries, although commonly included in FYR Executive Summaries, are
presented separately in this document with one summary for each project area included in its
respective section.
Well 12A
The Well 12A site includes OUs 1, 2 and 3 (together referred to as the "Well 12A OU") of the STC
Superfund Site. Well 12A is located in Tacoma, Washington approximately 5 miles south of
Commencement Bay and directly west of Interstate 5. Well 12A encompasses the source of
contamination at the property of the former Time Oil Company and the City of Tacoma's production
Well 12A.
The former Time Oil property was historically used for various industrial practices including oil
recycling and paint and lacquer manufacturing. Oil recycling and solvent processing began in the early
1920s and continued until 1991 with occasional interruptions due to changes in ownership and a large
fire in 1976. In addition to a number of possible leaks and spills over the years, some of the filter cake
generated during oil recycling was land-disposed around the Time Oil Building and additional filter
cake was used as fill material in 1982 for constructing the Burlington Northern Railroad spur to the
north of the Time Oil Property.
South Tacoma Channel Superfund Site Five-Year Review
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In 1981, chlorinated organic solvents were detected in groundwater at the City of Tacoma's Well 12A
in part per billion (ppb) concentrations (|ig/L) and above current drinking water criteria at that time.
The Remedial Investigation (RI) identified the contaminants of concern (COCs) in soil and
groundwater as tetrachloroethane (PCA), tetrachloroethene (PCE), trichloroethene (TCE), and trans-
1,2-dichloroethene (DCE).
The remedy for the site as set forth in the 1983 Record of Decision (ROD), 1985 first ROD
Amendment, and 1987 remedial design change memorandum included wellhead treatment at Well
12A using air strippers, vadose zone soil treatment by a Vapor Extraction System (VES), limited soil
excavation, and a Groundwater Extraction and Treatment System (GETS) that uses carbon adsorption
to treat extracted groundwater. In 2009, ROD Amendment #2 added shallow excavation to remove
additional source material, In-Situ Thermal Remediation (ISTR) to treat highly impacted portions of
the deep vadose zone and upper saturated zone, Enhanced Anaerobic Biodegradation (EAB) to treat
the high-concentration groundwater plume, Monitored Natural Attenuation (MNA) as a contingency,
groundwater monitoring, and institutional controls. In 2012 an Explanation of Significant Differences
(ESD) was completed which included demolition of the old Time Oil building in order to allow for
implementation of the ISTR portion of the remedy.
Construction of the remedial actions described in ROD Amendment #2 is still in progress. Shallow
soil contamination to the east of the Time Oil building has been excavated and transported off-site for
disposal. ISTR and EAB are still in the final stages of the design phase and are scheduled to be
complete by 2015. The GETS has been shut down prior to the start of the ISTR and EAB remedial
action, but may be reactivated following completion of these actions if Remedial Action Objectives
(RAOs) have not been met. Municipal water from Well 12A is treated via air-stripping prior to use.
ICs are in place to prevent exposure to shallow soil during remedial activities and to prevent ingestion
of contaminated groundwater.
Standards that have changed since the ROD, ROD Amendments, and ESD were signed may affect the
protectiveness of the remedy. Changes in toxicity values for cis-l,2-DCE, trans-1,2-DCE, 1,1,2,2-
PCA, PCE, and TCE have occurred in the last five years that may require future re-evaluation of
selected cleanup levels (cis-and trans-1,2-DCE) to ensure protectiveness is maintained. The changes
do not affect the current protectiveness since ICs are in place to prevent exposure above the new
standards.
Exposure pathways described in the ROD have not changed. The vapor intrusion pathway was not
evaluated during the ROD. USEPA plans to evaluate vapor intrusion after the remedial actions are
complete.
The remedy at Well 12A is expected to be protective of human health and the environment upon
completion. In the interim, remedial activities completed to date have adequately addressed all
exposure pathways that could result in unacceptable risks in these areas.
South Tacoma Channel Superfund Site Five-Year Review
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South Tacoma Field
The South Tacoma Field (STF) is OU 4 of the STC Superfund site. The STF OU is approximately 260
acres. The southern half of the OU contains industrial and commercial facilities; the northern and
western portions are primarily open grass fields.
A variety of industrial and commercial operations have occupied different portions of the OU in the
past 100 years including railroad vehicle manufacturing and repair, foundries, and aircraft
maintenance and refueling. In addition to potential historic contaminant sources, several present day
industrial facilities have contributed to the contaminant source areas. Tacoma Public Utilities (Tacoma
City Light) has operated a maintenance and repair facility at the northernmost end of the OU and
Pioneer Builders Supply purchased land in the southeast portion where USTs were installed.
In 1990, surface soils, and to a lesser extent, subsurface soils in the rail yard and foundry areas were
contaminated with high levels of lead, arsenic, copper, and zinc. At the foundry area on the south end
of the OU, a relatively small volume of nearly immiscible, heavy fuel oil was found on the surface of
the water table. At the Tacoma City Light Property on the north end of the site, elevated
concentrations of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and several
other organic compounds were detected in subsurface soils at and underlying some of the dry wells. At
Pioneer Builders Supply, elevated concentrations of 1,2,4-trichlorobenzene, PCBs, petroleum
hydrocarbons (TPH), benzene, ethylbenzene, toluene, and xylenes (BETX) were found in subsurface
soil in the unsaturated zone beneath and immediately surrounding the location where three USTs had
been removed. Benzene, ethylbenzene, and 1,1,2-trichloroethane (TCA) were detected at levels above
maximum contaminant levels (MCLs) in groundwater at this site.
The OU was divided into three areas for remediation: STF soils, Pioneer Builders Supply, and
Tacoma City Light drywells. The selected remedy for the STF soils consisted of excavation and
solidification of soil contaminated at levels that exceeded hot-spot concentration thresholds;
excavation, consolidation, and on-site containment (capping) of soil at levels that exceeded capping-
required levels; institutional controls; and groundwater monitoring. The remedy for Pioneer Builders
Supply consisted of monitored natural attenuation (MNA). The remedy for Tacoma City Light Dry
Wells included excavation of soil with final treatment through either incineration or off-site.disposal in
an approved landfill.
The soil remedies are complete; hot spots have been removed and treated on-site and the remaining
area of soil contamination have been removed, consolidated on-site, and capped. The ICs are in place
to protect direct contact of workers with contaminated soils and to prevent groundwater at Pioneer
Builders Supply from being use as drinking water. Fencing has been installed around the northern and
central portion of the site and at the main entrance to restrict access. Operation and maintenance
procedures are in place to ensure cap and fencing integrity.
Groundwater monitoring is used to assess impacts of the soil consolidation areas on local
groundwater. Concentrations of lead in two STF wells were above the cleanup level over the last three
years. A significant increase was observed in December 2012, during a period of higher groundwater
South Tacoma Channel Superfund Site Five-Year Review
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levels, and may indicate that some contaminated soil in the vadose zone was exposed to continuous
saturation that has not occurred in the past, resulting in some particulate or soluble material migrating
into the groundwater. The groundwater monitoring program should be modified to determine if there
is a continuing source of contamination to groundwater. MNA at Pioneer Builders Supply has been
slower than expected; however, concentrations recently dropped below cleanup levels. Monitoring
should continue to determine if MNA is effective.
Several Washington Model Toxics Cleanup Act (MTCA) standards have changed since the remedy
was selected. Washington Department of Ecology modified MTCA substantially in 2007. Revisions to
soil cleanup levels were primarily based on the protection of groundwater, so they do not likely impact
the protectiveness of the remedy with respect to industrial worker direct contact exposure but may
impact protectiveness of groundwater. Ongoing monitoring of groundwater will be conducted to
confirm that groundwater concentrations continue to meet current cleanup levels. There are no
changes in exposure pathways at the OU.
The remedy at the STF OU currently protects human health and the environment because ICs are in
place to prevent direct contact with soil and use of groundwater at Pioneer Builders Supply as drinking
water. However, in order for the remedy to be protective in the long term, the groundwater monitoring
program needs to be revised to determine if there is an ongoing source to groundwater from the
contaminated soils and to ensure protectiveness.
Tacoma Landfill
The City of Tacoma Refuse Utility operates a solid waste disposal facility known as the Tacoma
Landfill which is located within the City of Tacoma in Pierce County, Washington. The Landfill
covers 240 acres and is bounded approximately by South 31st Street on the north, Tyler Street on the
east, South 48th Street on the south, and Orchard Street on the west (see Figure ES-1).
The Tacoma Landfill began operations in 1960, and has been operating as a sanitary landfill under a
permit issued by the Tacoma Pierce County Health Department (TPCHD). The wastes disposed of at
the Landfill include garbage, rubbish, industrial wastes, construction and demolition wastes, street
refuse, litter, and bulky waste. The Landfill does not accept hazardous waste for disposal; however, the
Landfill received wastes in the 1960s and 1970s that have since been designated as hazardous wastes
under state and federal law. The Landfill has been filled. The last section of the Landfill to be filled is
called the Central Area which covers approximately 31 acres and was developed in 1987.
Groundwater contamination, primarily volatile organic compounds (VOCs), was detected at the
perimeter of the Landfill and extended in a southwesterly direction toward Leach Creek. Because of
the concern about public health effects of the contamination, particularly vinyl chloride, residents
whose wells were impacted or threatened were connected to the Tacoma municipal water system in the
mid-1980s. Landfill gases were also found to be migrating from the Landfill to residences and
businesses adjacent to the site.
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South Tacoma Channel Superfund Site Five-Year Review
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The remedy selected in the Record of Decision (ROD) included management of contaminant
migration using a groundwater extraction and treatment system (GETS); source control using a landfill
cap, gas extraction system, and landfill closure plan; and monitoring. Institutional controls (ICs) were
selected to assure that the remedial action will continue to protect human health and the environment.
The GETS has been effective at managing groundwater contaminant migration and most of the
extraction wells were shut down in 2010. Five extraction wells remain in operation, two near the
historical north area residual plume and three near the historical south area residual plume. Rebound
monitoring data indicate that there was a slight increase in contaminant concentrations in 2011;
however, concentrations have since decreased. The methodology developed for monitoring
containment in the 2010 Rebound Monitoring Plan is not appropriate for OU conditions and should be
revised prior to shutdown of any additional extraction wells. The reduced analyte list from the 2010
Groundwater Monitoring Plan should also be reviewed and revised as necessary to ensure all
necessary ROD-established COCs are still captured in the revised monitoring plan. The landfill-gas
system continues to control migration of landfill gas. Concentrations of methane above the lower
explosive limit (LEL) are still detected near the Home Depot property at the north end of the landfill.
New extraction wells have been installed in this area and their operation is being optimized to reduce
concentrations. Final closure of the Central Area will be completed by December 31, 2013. Following
this event, the Operations and Maintenance Plan for the Landfill Cap, Condensate Collection System
and Central Area Leachate Collection System and the Leachate and Condensate Management Plans
should be updated to reflect current site conditions. ICs are in place to assure the remedial action will
continue to protect human health and the environment. Several toxicity parameters have been updated
for multiple chemicals. However, performance standards still meet an acceptable level of risk at the
OU. There have been no changes to the exposure pathways that would impact protectiveness at the
OU.
The remedy at the Tacoma Landfill currently protects human health and the environment because the
groundwater and landfill gas is being controlled through the GETS and landfill-gas management
system, the Central Area final cover will be complete by December 31, 2013, and ICs are in place.
However, in order for the remedy to be protective in the long term, the following actions need to be
taken to ensure protectiveness:
• Continue operation optimization of gas extraction wells at the north end of the Landfill.
• Re-grade areas of the landfill cap prone to ponding and subsidence.
• Update the following management plans to ensure the monitoring program is effective and
response action procedures are in place: Operations and Maintenance Plan for the Landfill Cap,
Condensate Collection System and Central Area Leachate Collection System; Leachate and
Condensate Management Plan; Rebound Monitoring Plan; and Groundwater Monitoring Plan.
South Tacoma Channel Superfund Site Five-Year Review
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vi South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Summary Form
SITE IDENTIFICATION
Site Name: Commencement Bay, South Tacoma Channel Superfund Site
EPA ID: WAD980726301
Region: 10
State: WA
City/County: Tacoma/Pierce County
NPL Status: Final
Multiple OUs?
Yes
Has the site achieved construction completion?
Yes
Lead agency: EPA
If "Other Federal Agency" was selected above, enter Agency name:
Author name (Federal or State Project Manager): Howard Orlean (OU 1), Shawn Blocker
(OU 4 and OU 5/6)
Author affiliation: EPA Remedial Project Manager
Review period: September 2008 - September 2013
Date of site inspection: March 5, 2013 (OU 1, OU-4), April 2, 2013 (OU 5/6)
Type of review: Statutory
Review number: 4
Triggering action date: September 9, 2008
Due date (five years after triggering action date): September 9, 2013
South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Summary Form (continued)
Issues/Recommendations
()l (s) without Issues/Reconiniendiilions Identified in the l i\e-Ye;ir Rexiew:
NA
Issues and Recommendations I den I i lied in the li\e-Ye:ir Rexiew:
OU(s): OU 1,
Well 12A
Issue Category: Remedy Performance
Issue: Selected cleanup levels for cis- and trans-l,2-DCE may no longer be protective
following 2011 changes in toxicity values.
Recommendation: Re-evaluate the groundwater cleanup level for cis- and trans-1,2-
DCE and adjust if necessary to maintain future protectiveness after achievement Tier 1
criteria outlined in the 2009 ROD Amendment.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
EPA/State
EPA
09/2018
OU(s): OU 1,
Well 12A
Issue Category: Re
medy Performance
Issue: Evaluation of the vapor intrusion pathway is needed.
Recommendation: Evaluate vapor intrusion pathway after achievement of Tier 1
criteria.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
EPA
EPA
09/2018
viii
South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Summary Form (continued)
OU(s): OU 4,
South Tacoma
Field
Issue Category: Monitoring
Issue: Lead concentrations increased in two STF wells.
Recommendation: Modify the groundwater monitoring program to determine if there
is an ongoing source to groundwater from the contaminated soils.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA
09/2014
South Tacoma Channel Superfund Site Five-Year Review
ix
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Five-Year Review Summary Form (continued)
OU(s): OU 4,
South Tacoma
Field
Issue Category: Monitoring
Issue: Wells STM-1A and NMW-8A are damaged and have not been repaired.
Recommendation: Replace wells STM-1A and NMW-8A to ensure the groundwater
monitoring programs are complete.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA
09/2014
OU(s): OU 4,
South Tacoma
Field
Issue Category: Monitoring
Issue: The effectiveness of MNA at Pioneer Building Supply has not been evaluated as
recommended in the previous FYR.
Recommendation: Continue groundwater monitoring at Pioneer Builders Supply and
complete an evaluation of MNA. If future sampling shows an increase in concentrations,
similar to the historical fluctuations, the impact of potential residual soil contamination on
groundwater concentrations should be investigated. This could include additional soil and
groundwater sampling and an evaluation of groundwater flow variations on contaminant
concentrations.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA
09/2014
OU(s): OU 5/6,
Tacoma Landfill
Issue Category: Operations and Maintenance
Issue: Water ponding and cap subsidence continue to occur on areas of the landfill cap.
Recommendation: Regrade areas of the landfill cap that continue to have significant
ponding and subsidence.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA/State
09/2014
X
South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Summary Form (continued)
OU(s): OU 5/6,
Tacoma Landfill
Issue Category: Operations and Maintenance
Issue: The Operations and Maintenance Plan for the Landfill Cap, Condensate Collection
System and Central Area Leachate Collection System, and the Leachate and Condensate
Management Plan may not reflect current conditions following closure of the Central
Area.
Recommendation: Update the Operations and Maintenance Plan for the Landfill Cap,
Condensate Collection System and Central Area Leachate Collection System, and the
Leachate and Condensate Management Plan.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA/State
09/2014
OU(s): OU 5/6,
Tacoma Landfill
Issue Category: Operations and Maintenance
Issue: Landfill gas continues to be detected near the Home Depot Property at the north
end of the landfill.
Recommendation: Continue operation optimization of gas extraction in wells on the
northern edge of the Landfill near the Home Depot property.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA/State
09/2014
OU(s): OU 5/6,
Tacoma Landfill
Issue Category: Monitoring
Issue: The Rebound Monitoring Plan statistical methodology is too restrictive, leading to
numerous exceedances of the contingent action criteria, and the response action
procedures described in the plan have not been followed.
Recommendation: Update the Rebound Monitoring Plan.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA/State
09/2014
South Tacoma Channel Superfund Site Five-Year Review
xi
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OU(s): OU 5/6,
Tacoma Landfill
Issue Category: Monitoring
Issue: The 2010 Groundwater Monitoring Plan reduced the analyte list to those VOCs
useful for evaluating rebound. While this may be acceptable for the rebound monitoring
wells, it should not be used at locations used to determine compliance with ROD criteria,
such as Leach Creek surface water sampling and GETS effluent samples.
Recommendation: Update the 2010 Groundwater Monitoring Plan to include the full
list of ROD COCs for sampling locations used to determine compliance (e.g. Leach Creek
and GETS effluent).
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
No
Yes
PRP
EPA/State
09/2014
Protectiveness Statement(s)
Operable Unit: Protectiveness Determination: Addendum Due Date
(if applicable):
OU 1, Well 12A Short-term Protective
NA
Protectiveness Statement:
The remedy at Well 12 A OU is currently protective of human health and the environment in the short term. In
the interim, remedial activities completed to date have adequately addressed all exposure pathways that could
result in unacceptable risks in these areas. However in order for the remedy to be protective in the long term, the
remedial actions for the source area should continue to be implemented.
Operable Unit: Protectiveness Determination: Addendum Due Date
(if applicable):
OU4, South Tacoma Short-term Protective
Field NA
Protectiveness Statement:
The remedy at the South Tacoma Field OU is currently protective of human health and the environment in the
short term because ICs are in place to prevent direct contact with soil and use of groundwater at Pioneer Builders
Supply as drinking water. However, in order for the remedy to be protective in the long term, the groundwater
monitoring program needs to be revised to determine if there is an ongoing source to groundwater from the
contaminated soils and to ensure protectiveness.
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South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Summary Form (continued)
Operable Unit: Protectiveness Determination: Addendum Due Date
(if applicable):
OU 5/6 Short-term Protective
NA
Protectiveness Statement:
The remedy at the Tacoma Landfill is currently protective of human health and the environment in the short term
because the groundwater and landfill gas is being controlled through the GETS and landfill gas management
system, the Central Area final cover will be complete by December 31, 2013, and institutional controls are in
place. However, in order for the remedy to be protective in the long term, the following actions need to be taken
to ensure protectiveness: continue operation optimization of gas extraction wells at the north end of the Landfill;
re-grade areas of the landfill cap prone to ponding and subsidence, update the following management plans to
ensure the monitoring program is effective and response action procedures are in place: Operations and
Maintenance Plan for the Landfill Cap, Condensate Collection System and Central Area Leachate Collection
System; Leachate and Condensate Management Plan; Rebound Monitoring Plan; Groundwater Monitoring Plan
and Institutional Controls Plan.
Sitewide Protectiveness Statement (if applicable)
For sites that have achieved construction completion, enter a sitewide protectiveness determination
and statement.
Protectiveness Determination: Addendum Due Date (if applicable):
Short-term Protective NA
Protectiveness Statement:
The Commencement Bay, South Tacoma Channel Superfund Site is currently protective of human
health and the environment in the short term. In order for the remedy to be protective in the long term,
issues identified for OU 1 (Well 12A), OU 4 (South Tacoma Field) and OU 5/6 (Tacoma Landfill)
need to be resolved.
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South Tacoma Channel Superfund Site Five-Year Review xiv
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Contents
1. Well 12A, Operable Unit 1 3
1.1. Introduction 3
1.2. Site Chronology 4
1.3. Background 5
1.4. Remedial Actions 9
1.5. Progress Since the Last Five-Year Review 19
1.6. Five-Year Review Process 22
1.7. Technical Assessment 28
1.8. Issues 39
1.9. Recommendations and Follow-up Actions 39
1.10. Protectiveness Statements 40
1.11. Next Review 40
Well 12A Figures 42
Appendix 1 -A: Well 12 A List of Documents Reviewed 57
Appendix 1-B: Well 12 A Site Inspection Trip Report 61
Appendix 1-C: Well 12 A Site Inspection Checklist 79
Appendix 1-D: Well 12 A Interview Transcripts 89
Appendix 1-E: Well 12 Data Summary 103
2. South Tacoma Field, Operable Unit 4 109
2.1. Introduction 109
2.2. Site Chronology 110
2.3. Background 110
2.4. Remedial Actions 115
2.5. Progress Since the Last Five-Year Review 119
2.6. Five-Year Review Process 121
2.7. Technical Assessment 125
2.8. Issues 135
2.9. Recommendations and Follow-up Actions 135
2.10. Protectiveness Statements 136
2.11. Next Review 136
South Tacoma Field Figures 138
South Tacoma Channel Superfund Site Five-Year Review xv
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Appendix 2-A: South Tacoma Field List of Documents Reviewed 148
Appendix 2-B: South Tacoma Field Site Inspection Photographs 152
Appendix 2-C: South Tacoma Field Site Inspection Checklist 160
Appendix 2-D: South Tacoma Field Interview Transcripts 182
Appendix 2-E: South Tacoma Field Data Summary 194
3. Tacoma Landfill, Operable Unit 5/6 202
3.1. Introduction 202
3.2. Site Chronology 203
3.3. Background 204
3.4. Remedial Actions 207
3.5. Progress Since the Last Five-Year Review 223
3.6. Five-Year Review Process 227
3.7. Technical Assessment 236
3.8. Issues 244
3.9. Recommendations and Follow-up Actions 245
3.10. Protectiveness Statements 245
3.11. Next Review 246
Tacoma Landfill Figures 247
Appendix 3-A: Tacoma Landfill Documents Reviewed 261
Appendix 3-B: Tacoma Landfill Site Inspection Checklist 267
Appendix 3-C: Tacoma Landfill Site Inspection Photographs 289
Appendix 3-D: Tacoma Landfill Interview Transcripts 297
Appendix 3-E: Tacoma Landfill Data Summary 303
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South Tacoma Channel Superfund Site Five-Year Review
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List of Figures
Figure A. South Tacoma Channel Superfund Site Operable UnitsError! Bookmark not defined.
Figure 1-1. Site location map showing former Time Oil building and Well 12A 44
Figure 1-2. Representation of stratigraphic units 45
Figure 1-3. 2011/2012 final extent of excavation 46
Figure 1-4. Groundwater extraction and treatment system (GETS) location map 47
Figure 1-5. Proposed in-situ thermal remediation (ISTR) treatment area 48
Figure 1-6. Remedial Design investigation sampling locations and groundwater monitoring
wells 49
Figure 1-7. Groundwater monitoring wells including interim performance monitoring (IM) wells
and enhanced anaerobic bioremediation (EAB) wells 50
Figure 1-8. Contaminant mass zones in soil 51
Figure 1-9. Groundwater contours with groundwater extraction and treatment system (GETS)
operating (on) and with GETS not operating (off) 53
Figure 1-10. High-concentration groundwater plume extent 54
Figure 1-11. Baseline mass discharge measurements 55
Figure 2-1. South Tacoma Field Site Vicinity Map 139
Figure 2-2. South Tacoma Field Site Sub-Area Map 140
Figure 2-3. South Tacoma Field Major Historical Uses 141
Figure 2-4. Burlington Northern Ownership Tax Parcel Map at South Tacoma Field 142
Figure 2-5. South Tacoma Field Containment Areas 143
Figure 2-6. South Tacoma Field Monitoring Well Locations 144
Figure 2-7. Monitoring Well Locations Pioneer Builders Supply 145
Figure 3-1. Tacoma Landfill site vicinity map 249
Figure 3-2. Representative geologic cross-section 250
Figure 3-3. Tacoma Landfill extraction and monitoring wells 251
Figure 3-4. Tacoma Landfill sequence of fill operations 252
Figure 3-5. Tacoma Landfill gas extraction wells 253
Figure 3-6. Tacoma Landfill gas monitoring probes 254
Figure 3-7. Tacoma Landfill capture zones 4th quarter 2008 255
Figure 3-8. Tacoma Landfill monitoring well status table 256
Figure 3-9. Tacoma Landfill groundwater monitoring analytic schedule 259
South Tacoma Channel Superfund Site Five-Year Review
xvii
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List of Tables
Table 1-1. Chronology of Site Events for Well 12A 4
Table 1-2. Summary of ROD, ROD Amendments, and ESD for Well 12A 10
Table 1-3. Well 12A Pretreatment data 17
Table 1-4. Recent GETS effluent data 18
Table 1-5. Summary of Groundwater ARAR Changes 32
Table 1-6. ARARs Analysis 33
Table 1-7. Exposure Pathways 35
Table 1-8. Toxicity Value Changes 36
Table 1-9. Issues 39
Table 1-10. Recommendations and Followup Actions 40
Table 2-1. Chronology of Site Events 110
Table 2-2. South Tacoma Field Contaminants of Concern 114
Table 2-3. Mann-Kendall Trend Test Results, Well NMW-1A 123
Table 2-4. Changes in Chemical-Specific Standards 129
Table 2-5. Changes in Action-Specific Requirements 133
Table 2-6. Changes in Location-Specific Requirements 134
Table 2-7. Issues for the South Tacoma Field OU 135
Table 2-8. Recommendations and Followup Actions 135
Table 3-1. Chronology of Site Events, Tacoma Landfill, OU5/6 203
Table 3-2. Residential Well Status 221
Table 3-3. Institutional Controls Summary and Status 234
Table 3-4. Changes in Chemical-Specific Standards 241
Table 3-5. Changes in Action-Specific Requirements 243
Table 3-6. Issues 244
Table 3-7. Recommendations and Followup Actions 245
xviii
South Tacoma Channel Superfund Site Five-Year Review
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List of Abbreviations
3D
Three dimensional
ARAR
Applicable or Relevant and Appropriate Requirements
ATSDR
Agency for Toxic Substances and Disease Registry
AWQC
ambient water quality criteria
bgs
below ground surface
BLUS
Building and Land Use Services
BNRR
Burlington Northern Rail Road
BNSF
Burlington Northern Sante Fe
BOD
biological oxygen demand
BTEX
benzene, toluene, ethylbenzene and xylenes
BTU
British thermal unit
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act
cfm
cubic feet per minute
cfs
cubic feet per second
CHB
Citizens for a Healthy Bay
CLARC
Cleanup Levels and Risk Calculations
COC
contaminant of concern
COD
chemical oxygen demand
CSCL
Confirmed and Suspected Contaminated Sites List
CSM
Conceptual Site Model
CTP
Central Wastewater Treatment Plant
DCA
dichloroethane
DCE
dichloroethene
DNAPL
dense non-aqueous phase liquid
DOH
Department of Health
EAB
Enhanced anaerobic bioremediation
Ecology
Washington State Department of Ecology
EOP
end of plume
EPA
Environmental Protection Agency
ESD
Explanation of Significant Differences
FFS
Focused feasibility study
FS
Feasibility study
ft/day
feet per day
FYR
Five Year Review
GAC
Granular activated carbon
GCL
geosynthetic clay liner
GETS
Groundwater extraction and treatment system
gpm
gallon per minute
HDPE
high density polyethylene
HELP
Hydrologic Evaluation of Landfill Performance
HHRA
human health risk assessment
HI
Hazard Index
HQ
Hazard quotient
South Tacoma Channel Superfund Site Five-Year Review
xix
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IC
Institutional control
IDW
Investigation derived waste
IRM
Interim remedial measure
IRIS
Integrated Risk Information System
ISTR
In-situ thermal remediation
J&E
Johnson and Ettinger
LDR
Land Disposal Restrictions
LEL
lower explosive limit
LNAPL
Light non-aqueous phase liquid
MCL
Maximum contaminant level
mil
milliliter
MNA
Monitored natural attenuation
msl
mean sea level
MTCA
Model Toxics Control Act
MVS
Mining Visualization Software
l-ig/L
microgram per liter
NCP
National Contingency Plan
NPL
National Priority List
NRWQC
National Recommended Water Quality Criteria
O&M
Operation and maintenance
OU
Operable Unit
PAH
polyaromatic hydrocarbons
PCA
tetrachloroethane
PCB
polychlorinated biphenyls
PCE
T etrachloroethene
POC
point of compliance
ppb
part per billion
ppm
part per million
PRG
preliminary remediation goal
PRP
Potentially responsible party
PSCAA
Puget Sound Clean Air Agency
RAO
Remedial Action Objective
RCRA
Resource Conservation and Recovery Act
RD
Remedial Design
RfD
reference dose
RI
Remedial Investigation
ROD
Record of Decision
RPM
remedial project manager
RSE
Remediation system evaluation
RSL
risk screening level
SDICP
Site Development and Institutional Control Plan
STC
South Tacoma Channel
STF
South Tacoma Field
SVE
Soil vapor extraction
TBC
To Be Considered
TCA
trichloroethane
XX
South Tacoma Channel Superfund Site Five-Year Review
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TCE
trichloroethene
TDS
total dissolved soilds
TPCHD
Tacoma Pierce County Health Department
TPH
total petroleum hydrocarbons
USACE
United States Army Corps of Engineers
UST
Underground storage tank
VES
Vapor extraction system
VOC
Volatile organic compound
South Tacoma Channel Superfund Site Five-Year Review
xxi
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xxii South Tacoma Channel Superfund Site Five-Year Review
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Organization of This Report
The Commencement Bay, South Tacoma Channel (STC) Superfund site is located in Tacoma, Pierce
County, Washington. Although the STC was listed on the National Priorities List (NPL) as a single site
due to the proximity of three different problem areas in south Tacoma, the three areas are distinctly
different with separate problems, remedies, and approaches to protectiveness. The three main project
areas (Well 12A, South Tacoma Field (STF), Tacoma Landfill) are broken down into the following
Operable Units (OUs) within the STC:
• OU 1 - Well 12A/groundwater
• OU 2 - Well 12A Burlington Northern Soil Removal
• OU 3 - Well 12A Soils (Vapor Extraction System)
• OU 4 - South Tacoma Field (STF)
• OU 5 - Tacoma Landfill/cap
• OU 6 - Tacoma Landfill/groundwater
This report contains five-year reviews (FYRs) for three separate project areas. Section 1 contains the
complete FYR for Well 12A OU1 including all figures and appendices; Sections 2 and 3 each contain
another separate and complete FYR for STF OU 4 and Tacoma Landfill OU 5/6, respectively. Note the
Burlington Northern Soil Removal and Well 12A Soils/Vapor Extraction System were designated as OUs
2 and 3 for administrative purposes, but are actually remedy components of the overall Well 12A remedy,
which is designated as OU1. This FYR addresses the entire Well 12A project area including any
remaining exposures from OUs 2 and 3 as OU1, and OUs 2 and 3 are not mentioned further in this
document. Figure A shows locations of the three project areas within the STC Superfund site. The
following table summarizes current status and recommendations addressed in this review.
OU 1, Well 12A
1
-------
©allenmur'e
r ^ 'Q
LlGOtf CLUB
WTst
Firerest
Well 12,
, Whiivft* ScV—'.
»cnij*t
TACOSU
I South
Tacoma
Field
Mt Tlhom«
lllfih Sch
j4 Gravel Pi I
OMfcAOOW PARK
1 GOLT COURSE
South Tacoma Channel Superfund Site
Operable Units
0 200 400 800 Source:
Feet USGS Topographic Map, Tacoma South, WA, 1997
USGS Topographic Map, Steilacoom, WA, 1997
Figure A. Location of Project Areas in the South Tacoma Channel Superfund Site
2
South Tacoma Channel Superfund Site Five-Year Review
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Well 12A, Operable Unit 1
The Well 12A site has three OUs; however, OUs 2 and 3 were designated for administrative purposes.
They are actually remedy components of the overall Well 12A remedy, which is designated as OU1;
therefore, OUs 2 and 3 are not mentioned further in this review.
1.1. Introduction
This is the fourth FYR for the Well 12A project area (EPA ID No. WAD980726301), OU 1. The
triggering action for this review is the date of the last five-year review for the Well 12A project area,
completed in September 2008. The FYR is required due to the fact that hazardous substances, pollutants,
or contaminants remain at the site at levels above those that would allow for unlimited use and
unrestricted exposure.
1.1.1. Purpose
The purpose of a five-year review is to determine whether the remedy at a site is protective of human
health and the environment. The methods, findings, and conclusions of reviews are documented in FYR
reports. In addition, FYR reports identify issues found during the review, if any, and recommendations to
address them.
1.1.2. Authority
The United States Environmental Protection Agency (EPA) is preparing this five-year review pursuant to
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) §121 and the
National Contingency Plan (NCP). CERCLA §121 states:
If the President selects a remedial action that results in any hazardous substances,
pollutants, or contaminants remaining at the site, the President shall review such
remedial action no less often than each five years after the initiation of such remedial
action to assure that human health and the environment are being protected by the
remedial action being implemented. In addition, if upon such review it is the judgment
of the President that action is appropriate at such site in accordance with section
[104] or [106], the President shall take or require such action. The President shall
report to the Congress a list offacilities for which such review is required, the results
of all such reviews, and any actions taken as a result of such reviews.
The EPA interpreted this requirement further in the NCP; 40 CFR §300.430(f)(4)(ii) states:
If a remedial action is selected that results in hazardous substances, pollutants, or
contaminants remaining at the site above levels that allow for unlimited use and
unrestricted exposure, the lead agency shall review such action no less often than
every five years after the initiation of the selected remedial action.
With oversight from EPA Region 10, the United States Army Corps of Engineers (USACE) Seattle
District has conducted an FYR of the remedial actions implemented at the Well 12A Operable Unit (OU)
OU 1, Well 12A
3
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1 of the South Tacoma Channel (STC) Superfund Site located in Tacoma, Washington. The Well 12A
project area also includes two other OUs (OU 2 Burlington Northern Rail Road (BNRR) Soil Removal
and OU 3 Vapor Extraction System) that have completed actions summarized in this document. This
section documents the results of the Well 12A project area review, which was conducted from January
2013 through September 2013. (Reviews of the other two active OUs, 4 and 5/6, are documented in
Sections 2 and 3 of this document, respectively.)
1.2. Site Chronology
Table 2-1 lists major activities and milestones for the Well 12A site/OUl.
Table 2-1. Chronology of Site Events for Well 12A
Event
Date
Site Discovery
September 1981
Interim Priority NPL listing
November 1981
NPL listing
September 8, 1983
Phase I Remedial Investigation(RI)/Focused Feasibility Study (FFS) completed
January 1983
Record of Decision (ROD) Signature (Well 12A Stripping Towers Interim Remedial Measure
(IRM))
March 18, 1983
Air Strippers begin operation at Well 12A
July 17, 1983
ROD Amendment (addressing source treatment)
May 3, 1985
Phase II Remedial Investigation/Feasibility Study completed
May 3, 1985
Unilateral Order (Potentially Responsible Party (PRP) 1)
June 3, 1985
Remedial Design Start - Groundwater
April 19, 1985
Remedial Design Complete - Groundwater
April 23, 1987
Remedial Design Modification (requiring soil vapor extraction system (VES)/carbon
adsorption)
April 28, 1987
Remedial Design Start - Soil
March 19, 1985
Groundwater Extraction and Treatment System (GETS) begins operation
November 1988
Consent Decree for Settlement (PRP1)
November 4, 1988
Remedial Design Complete - Soil
June 5, 1991
Remedial Action Start -Soil Vapor Extraction (SVE)
July 19, 1990
SVE system begins operation
August 1993
Consent Decree for Settlement (PRP2)
January 31, 1995
Extraction Wells 2, 3, 4, and 5 added to GETS
1995
Remedial Action Complete - SVE shut down
November 1, 1997
First Five-Year Review
July 16, 1998
Light Non-aqueous Phase Liquid (LNAPL) and Soil Investigation Report
September 1999
CB/STC Construction Completion
September 29, 1999
Remediation System Evaluation (RSE)
December 10, 2001
4
South Tacoma Channel Superfund Site Five-Year Review
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Event
Date
Second Five-Year Review
July 2003
Capture Zone Analysis
September 2005
Third Five-Year Review
September 2008
Focused Feasibility Study (FFS) Completed
April 2009
ROD Amendment #2 (requiring additional source treatment)
October 2009
Remedial Design Investigation Conducted
October 2010
Shallow Excavation and Underground Storage Tank (UST) Removal Completed
May 2012
Explanation of Significant Differences (ESD) to the Amended ROD
June 2012
Remedial Design and In-Situ Thermal Remediation (ISTR) Pre-Design Investigation Complete
July 2012
Mass Discharge Baseline Complete
January 2013
1.3. Background
1.3.1. Physical Characteristics
The Well 12A project area of the STC Superfund site is located in Tacoma, Washington, approximately 4
miles southwest of the southern-most tip of Commencement Bay near the junction of Interstate 5 and state
Highway 16 (Figure 2-1). The Well 12A project area encompasses the source of contamination at the
property of the former Time Oil Company, and includes Well 12A, a municipal water supply production
well owned and operated by the City of Tacoma. Well 12A is now typically pumped only during the peak
water demand seasons (summer or early fall). The former Time Oil Company is located at 3011 South
Fife Street, and Well 12A is located on Pine Street between 38th Avenue and South Tacoma Way.
1.3.1.1 Site Geology
The Well 12A project area is located in the Puget Sound Lowlands within the Commencement Bay
drainage area. It is underlain by a sequence of glacial and interglacial deposits from the most recent
glaciation. Several distinct channels were cut into these deposits by high velocity glacial meltwater, one
of which is the South Tacoma Channel over which the site is situated. Where saturated, the coarse sands
and gravels associated with these deposits make them conducive for high aquifer yields.
Stratigraphy in the vicinity of the site is complex and characterized by discontinuous lenses of high and
low permeability sediments. The primary units of interest at the site are described below (presented from
shallowest to deepest). A three dimensional (3D) representation of the units is shown on Figure 2-2.
Hydraulic conductivity values are included, where appropriate, to show the relative permeability of each
unit.
• Filter Cake and Artificial Fill. Fill material consists of material of variable grain size. Filtering of the
tar-like sludge on the bottom of the waste oil tanks resulted in a filter cake material which was used as
fill at various locations throughout the site.
OU 1, Well 12A
5
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• Steilacoom Gravels (Qvs). Generally characterized as gravelly sand and sandy gravel with varying
silt content.
• Vashon Till (Qvt). Generally characterized as a diamict with a silty sand matrix supporting gravel and
lesser amounts of cobbles and boulders.
• Vashon Advance Outwash Deposits (Qva). Generally characterized as poorly graded medium sand
with varying amounts of gravel and silt. The water table is typically encountered in the Qva unit.
Hydraulic conductivity in this unit has been calculated at 6-56 feet per day (ft/day).
• Sedimentary Deposits of pre-Fraser Glaciation Age, Undifferentiated (Qpf). Mixed fine and coarse
grained deposits. Two non-contiguous fine-grained silt or clayey silt layers have been identified at the
site; one generally above 200 feet (ft) mean sea level (msl) and one below 200 ft msl. Hydraulic
conductivity within the fine-grained layer has been calculated at 0.12 ft/day.
• Coarse-Grained Deposits of pre-Fraser Glaciation Age (Qpfc). Generally characterized as coarse
grained sand and gravel with varying amounts of silt and intermittent layers of saturated silty gravel.
Hydraulic conductivity is highly variable: in gravel and sand layers it ranges from 58-3,555 ft/day and
in silty sand or silty gravel layers it ranges from 0.9 to 10 ft/day.
• Coarse Grained Glacial Deposits of pre-Olympia Age (Qpogc). Similar in character to the overlying
Qpfc. A color change and increase in fines were observed at the transition between the Qpfc and
Qpogc. Measured hydraulic conductivities measured in the transition zone ranged from 0.6-1.5 ft/day.
Well 12A is believed to be screened in the coarse sand and gravels layers within this unit. Hydraulic
conductivities calculated from the Welll2A aquifer test ranged from 874-5,921 ft/day.
• Till of pre-Olympia Age (Qpogt). Generally characterized as a very dense and dry sand and silt with
fine gravel and a diamicitic texture characteristic of glacial till. This unit marks the upper portion of
the primary aquitard at the site.
• Pre-Olympia deposits, undifferentiated (Qpon). Generally characterized as very dense or hard gravel,
sand, silt and clay.
1.3.1.2 Hydrogeology
Groundwater in the upper aquifer is typically first encountered in the Qva unit at 30 to 35 feet below
ground surface (bgs). The upper aquifer extends to approximately 100 feet bgs. Where present, the fine-
grained Qpf unit may provide localized confining conditions. The principal aquitard (Qpogt), is a semi-
confining unit approximately 30-40 feet thick that separates the upper from the lower aquifer. The lower
aquifer is estimated at approximately 40 feet thick and is underlain by the Kitsap Formation, a regional
confining unit.
Groundwater flow at the site is complex due to multiple influences. The regional groundwater flow
direction, without any impacts from pumping, is generally toward the east to northeast. When Well 12A is
operational, the gradient shifts to the southwest. Additional discussion of groundwater flow is presented
in Section 1.6.4.3.
1.3.2. Land and Resource Use
Current land use near the former Time Oil property and Well 12A is commercial and industrial. The
former Time Oil property is currently under private ownership and is used by Western Moving and
Storage for storage and office space.
6
South Tacoma Channel Superfund Site Five-Year Review
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Groundwater in the aquifer underlying the project area is currently used as a drinking water source for the
City of Tacoma. Thirteen production wells located within the South Tacoma Channel are primarily used
to augment inadequate supply from the Green River during periods of high demand or high turbidity.
Well 12A is operated infrequently due to the expense of treatment. At a minimum, City of Tacoma wells
are operated once every two years to check their operation.
The Well 12A project area is located within the South Tacoma Groundwater Protection District, which is
a special zoning overlay district used to prevent the degradation of groundwater in the South Tacoma
aquifer (Tacoma Municipal Code 13.09). It is managed by the Tacoma Pierce County Health Department
(TPCHD). Certain facilities within this district are regulated based on their use or handling of hazardous
substances. Regulated facilities are issued permits and are inspected biennially.
1.3.3. History of Contamination
The former Time Oil property was historically used for various industrial practices including oil recycling
and paint and lacquer manufacturing. Oil recycling and solvent processing began in the early 1920s and
continued until 1991 with occasional interruptions due to changes in ownership and a large fire in 1976.
The Time Oil Company vacated the property 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 land-disposed around the Time Oil Building and additional filter cake was used
as fill material in 1982 for constructing the Burlington Northern 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), trichloroethylene (TCE), and other organic solvents
discovered in the groundwater at Well 12A.
1.3.4. Initial response
Discovery and NPL Listing. In 1981, chlorinated organic solvents were detected in groundwater at Well
12A that were above drinking water criteria at that time. As a result, the City of Tacoma Water
Department voluntarily removed Well 12A from production during September of that year. EPA
completed a site investigation between July and September 1981 and proposed the Commencement
Bay/South Tacoma Channel site for listing on the National Priority List (NPL) on September 1, 1981. The
site was added to the NPL on September 8, 1983.
Phase I Remedial Investigation. EPA authorized a Remedial Investigation (RI) to determine the source,
type, and extent of contamination in April 1982. Eleven groundwater wells were installed and the results
of subsequent groundwater sampling and analysis revealed the following concentrations of contaminants
of concern (COCs) on site:
• trans-1,2-dichlorocthcnc (DCE) — 30 to 100 (ig/L;
• PCA —17 to 300 (ig/L;
• PCE — 1.6 to 5.4 (ig/L; and
• TCE — 54 to 130 (ig/L.
OU 1, Well 12A
7
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The RI study also determined that the major source of contamination was generally located northeast of
Well 12A and that the natural, undisturbed groundwater flow direction was east and away from Well 12A.
However, with the well field in production, the groundwater flow direction reversed, and the contaminant
plume traveled toward the production wells.
The RI concluded that continued pumping of Well 12A could capture the contaminant plume even if other
production wells were pumping. That is, pumping Well 12A could provide a hydraulic barrier to the
spread of contamination and protect the rest of the well field. It was hypothesized that if Well 12A was
not pumped to provide a hydraulic barrier, other operating wells could be impacted by the contaminant
plume and could be lost for drinking water use.
Phase I Focused Feasibility Study/Initial Remedial Measures. In January 1983, EPA conducted a
Focused Feasibility Study (FFS) to determine the most cost-effective treatment for Well 12A that would
protect the drinking water supply for the City of Tacoma. The study included an Endangerment
Assessment that evaluated risks to the general population if no action was taken. The FFS recommended
that an extraction and treatment (i.e., pump and treat) system with air stripping be implemented on an
interim basis for treatment of Well 12A groundwater to control the spread of contamination and prevent
the loss of the well field. Carbon adsorption was also considered for treatment of groundwater but was
more expensive and was (initially) eliminated from further evaluation for use on site.
On March 16, 1983, EPA signed a Record of Decision (ROD) for a Remedial Action calling for the
design and construction of five air stripping towers at Well 12A operating in parallel to treat up to 3,500
gallons per minute (gpm) of contaminated Well 12A groundwater. The ROD required treatment to be
sufficiently protective of either human consumption or of aquatic life if discharged either to
Commencement Bay or to the city's sanitary sewer system. The decision criterion used to determine
discharge requirements was the concentration equivalent to a lxlO"6 excess cancer risk level as measured
at the tap (after treatment and dilution in the system). Construction of the treatment system was
authorized on March 24, 1983, and system startup occurred on July 17, 1983. The system was operated by
the City of Tacoma until early November 1983 when production from the well field for that year's peak
demand was no longer needed. Since that time, operation of the Well 12A treatment system of air
stripping towers has continued on a seasonal basis (during peak demand) to reduce impact to the
remaining well field and will continue until remediation is completed.
Phase II RI/FS. Because the Phase I RI identified only a general source location and not a specific site,
EPA authorized a study of historical solvent use and disposal practices in the suspect area in December,
1982. Records of past investigations by TPCHD, Tacoma Water Division, and the Washington State
Department of Ecology (Ecology) were reviewed and interviews were conducted with owners of
numerous businesses in the area. A follow-up study focused on the historical uses and disposal of PCA in
the vicinity of Well 12A. The focus on PCA was based on the fact that the RI determined this chemical to
be the predominant contaminant and an uncommonly used solvent. Since few businesses nearby used
PCA, these studies reduced both the number and location of potential sources of the contamination by
process of elimination.
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South Tacoma Channel Superfund Site Five-Year Review
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In May 1983, EPA authorized a supplemental Remedial Investigation and Feasibility Study (RI/FS) to
further define the extent of groundwater contamination and to attempt to locate the source. Four
monitoring wells were installed and sampled. Groundwater located near the Time Oil property contained
concentrations of TCE, PCA, and trans- 1,2-DCE in the low parts per million (ppm) range, which was
substantially higher than detections in other wells, and orders of magnitude higher than at Well 12A. It
was consequently determined that these monitoring wells were at or near the source of contamination.
With the apparent source area narrowed down substantially, EPA obtained air samples and near-surface
soil samples along the Burlington Northern railroad spur north of the Time Oil property. Air sampling
results showed very low contamination levels, but soil samples contained significant concentrations of
TCE and PCA, confirming that this was the source of the contamination. The soil underlying the railroad
track was composed of a fine-grained filter cake that had been generated during oil reprocessing
operations at the site and disposed of on site. The filter cake consists of a tar-like sludge filtered from
treated waste oil and is contaminated with high concentrations of lead (1 to 2%) as well as chlorinated
organics.
Remedial alternatives were then developed to treat both the soil and the groundwater at the source and a
proposed plan was issued for public comment.
1.3.5. Basis for Taking Remedial Action
As noted above (Section 1.3.4), the 1983 RI identified four COCs: trans-1,2-DCE, PCA, TCE, and PCE.
The 2009 ROD Amendment #2 added two additional COCs (cis-1,2-DCE, and vinyl chloride), thereby
establishing the current list of COCs in groundwater for the site as follows:
• cis-1,2-DCE
• trans-1,2-DCE
• PCA
• PCE
• TCE
• vinyl chloride
All COCs have been detected in groundwater at levels above either the Maximum Contaminant Levels
(MCLs) or Washington State Model Toxics Control Act (MTCA) cleanup levels (USEPA, 2009). The
Endangerment Assessment (associated with the Phase I FFS) determined that public health may be
threatened either by direct contact at the source area or by consumption of contaminated drinking water if
no additional remedial action was taken. On the basis of these findings, remedial action was determined to
be warranted to mitigate risks to human health and the environment.
1.4. Remedial Actions
The following sections summarize the remedial actions selected in the decision documents, describe the
implemented remedial actions, and summarize the operation and maintenance (O&M) activities of the
OU 1, Well 12A
9
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existing remedial systems. A summary of the interim and final remedial actions by decision document is
presented in Table 2-2.
1.4.1. Remedy Selection
Table 2-2. Summary of ROD, ROD Amendments, and ESD for Well 12A
Date
Decision
Document
Remedial Action/Components
March 16,
1983
ROD
Interim Measure:
• Installation of air stripping system at Well 12A
• Pumping Well 12A to provide a hydraulic barrier
May 3,
1985
ROD
Amendment
(first)
Address soil and groundwater contamination within source areas:
• Excavation and removal of filter cake and contaminated soils in and
around Time Oil Building and along the Burlington Northern Rail Road
(BNRR) rail spur
• Installation of GETS using air stripping for treatment
• Soil flushing using treated water in areas of higher soil contamination
• Capping in areas of lesser soil contamination
April 28,
1987
Remedial Design
changes
documented in
Memorandum to
Regional
Administrator
Enhance soil and groundwater remedial action:
• Installation of Soil Vapor Extraction (SVE) system instead of soil
flushing
• Use of carbon adsorption for GETS treatment instead of air stripping
October
29, 2009
ROD
Amendment #2
Enhance soil and groundwater remedial action via:
• Shallow excavation, in-situ thermal remediation (ISTR). and enhanced
anaerobic bioremediation (EAB) of source material
• IC requirement to avoid/limit exposure to contamination
• Continued operation of air-stripping units at Well 12 A with
contingency for Monitored Natural Attenuation (MNA)
• Continued plume monitoring
• Continued O&M of the air strippers and groundwater monitoring at
Well 12A
June 14,
2012
Explanation of
Significant
Differences
(ESD)
Additional site characterization required modifications to the 2009 remedy:
• Remove the Time Oil Building to allow access to highly contaminated
soils
TBD
Future Decision
Document
Following completion of remedial actions in ROD Amendment #2 and post-
completion monitoring for a reasonable amount of time, this proposed decision
document will select the final remedy for groundwater.
The ROD, issued March 18, 1983, provided an Interim Remedial Measure (IRM) to address groundwater
contamination at Well 12A. The 1983 remedy involved the installation and operation of an air-stripping
system that would treat water pumped from Well 12A using five aeration towers operating in parallel.
Treated water would be discharged to Commencement Bay or to the city's drinking water system
depending on measured quality and the city's need. This remedy was meant as an interim measure until
the source area could be identified and the contamination mitigated (USEPA, 1983).
Following the RI and FS (discussed in 1.3.4), the ROD was amended in May 1985 to require
identification of source areas and treatment for soil and groundwater contamination within those source
areas. The first ROD Amendment selected several major elements, including: continuation of the
10
South Tacoma Channel Superfund Site Five-Year Review
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treatment at Well 12A using air stripping, excavation of contaminated soils, installation of a groundwater
extraction and treatment system (GETS) using air stripping for treatment, and additional soil treatment by
flushing using the extracted and treated groundwater, and capping of less-contaminated soils. The first
ROD Amendment granted the EPA regional administrator authority to approve modifications to the
choice and operation of certain aspects of the treatment system and soil remedy which are found to be
"equivalent in effectiveness and cost or are necessary for the protection of health and the environment"
(USEPA, 1985).
The IRM was amended in an April 28, 1987, memorandum to the Regional Administrator to include soil
treatment by soil vapor extraction (SVE) instead of soil flushing and to include treatment of contaminated
groundwater using carbon adsorption instead of air stripping in the Groundwater Extraction and
Treatment System (GETS). These treatment systems were proposed to augment the air stripping system
used for treatment of Well 12A groundwater that was used only during periods of peak demand. Selection
of soil cleanup levels was postponed to a subsequent decision document.
In 2004-2005, EPA installed additional monitoring wells and collected soil samples and groundwater
samples. Oily product was identified in some soil samples primarily collected from areas to the east of the
Time Oil building. Groundwater contaminant concentrations and distribution had generally decreased
compared to previous sampling events, although elevated concentrations of COCs were still found near
the Time Oil property. In 2008, the third FYR concluded that the GETS was no longer effectively
reducing contaminant concentrations and was not adequately controlling the migration of contamination
(USEPA, 2008). Since the report concluded that the remedy was not protective, corrective actions were
initiated.
In 2009, a Focused Feasibility Study (FFS) analyzing potential remedial alternatives to address ongoing
contamination was completed (CDM, 2009). Shortly thereafter, a second amendment to the ROD was
completed in October 2009 to address the COCs remaining in soil and groundwater. ROD Amendment #2
required continued operation of the GETS and treatment at Well 12A while adding the following remedy
components:
• Excavation and off-site disposal of filter cake and contaminated soils;
• In-situ thermal remediation (ISTR) of soil and groundwater
• In-situ enhanced anaerobic bioremediation (EAB) of groundwater;
• Institutional controls (ICs) to avoid or limit exposure to site contamination and guide the use of the
aquifer;
• Continued O&M of the GETS to prevent contaminant migration, with a contingency for monitored
natural attenuation (MNA) to achieve further remediation once interim objectives have been
achieved.
• Monitoring of the plume;
• Continued O&M of the air stripping units and groundwater monitoring for VOCs at Well 12A.
The remedy selected in Amendment #2 is considered a final remedy for soils and an interim remedy for
groundwater that will be protective and assist in achieving the long-term objective of restoring the aquifer
to its beneficial use as a drinking water source for the City of Tacoma.
OU 1, Well 12A
11
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During remedial design investigations, more residual source material was discovered beneath the Time
Oil Building than was previously known. To address the additional source material, an Explanation of
Significant Differences (ESD) was completed in June 2012 that modifies the remedy to include removal
of the Time Oil Building to allow access to highly contaminated soils.
1.4.2. Remedial Action Objectives
In order to protect human health and the environment, ROD Amendment #2 replaced and updated the
Remedial Action Objectives (RAOs) for the site. Fundamental changes were implemented to improve
overall remedy effectiveness and permanence and increase the probability of achieving the ultimate goal
of groundwater restoration. The RAOs were based on the updated conceptual site model (CSM) which
identified four zones/areas that needed to be addressed:
• Filter cake and shallow impacted soil.
• Deep vadose zone soil and high-concentration groundwater east of the Time Oil building.
• High-concentration groundwater west and south of the Time Oil building. This area is defined by
groundwater with COC concentrations greater than 300 (ig/L.
• Low-concentration groundwater. This area is defined by groundwater with COC concentrations less
than 300 (ig/L.
Based on these definitions, RAOs for the site are:
1. Eliminate the risk to human health posed by direct contact with filter cake and contaminated soil
at and near the surface still present on the east side of the Time Oil building;
2. Prevent or minimize the migration of contamination from the highly contaminated shallow soil
and filter cake area into the deeper soils to prevent further degradation of groundwater;
3. Remove sufficient contaminant mass within the source area to reduce the transport of
contaminants from this highly contaminated source material into down-gradient groundwater;
4. Reduce contaminant mass discharge by 90% from the source area into the low-concentration
groundwater treatment zone;
5. Reduce contaminant concentrations to meet cleanup levels selected in this amendment to be
protective of human health and the environment and to comply with all ARARs at specified
points of compliance;
6. Eliminate risk to human health from exposure to groundwater containing COCs in excess of
protective levels.
Amendment #2 further subdivided compliance with the RAOs into three tiers to allow implementation of
a multi-component remedy and allow for decision-making such as when to transition from one treatment
technology to another and when to transfer O&M to the State of Washington Department of Ecology
(Ecology).
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South Tacoma Channel Superfund Site Five-Year Review
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• 1st Tier - Address residual sources, minimize risk to receptors due to contaminated surface soils and
achieve a contaminant mass discharge reduction of at least 90% from the high-concentration source
area. Soil removal, ISTR, and EAB will be considered complete and the Remedy will be considered
operational and functional when Tier 1 criteria have been met. O&M will be turned over to Ecology
when Tier 1 criteria have been met.
• 2nd Tier - Achieve cleanup levels at interim performance monitoring points (within the current
groundwater plume) to ensure groundwater concentrations are below applicable or relevant and
appropriate requirements (ARAR)-specified levels at these locations.
• 3rd Tier - Determine if cleanup levels can be achieved in a reasonable timeframe throughout the
contaminant plume by discontinuing GETS operation and continuing to monitor natural attenuation of
any remaining contamination. If this demonstrates that cleanup levels could be achieved in a
reasonable timeframe with MNA only, the MNA contingency will be implemented and GETS
operation discontinued. If compliance with ARARs throughout the plume is deemed not feasible,
additional remedial alternatives or a Technical Impracticability waiver may be sought for non-
compliant portions of the aquifer.
1.4.3. Remedy Implementation
Collectively, the original ROD and ROD Amendments selected a multi-component remedy that was
adapted as more information became available. Each component of the selected remedy is described
below.
1.4.3.1 Well Head Treatment at Well 12A
The original 1983 ROD selected wellhead treatment at Well 12A using air strippers to treat pumped
groundwater. This remedy was meant as an interim measure until the source area could be identified and
the contamination mitigated. The air stripping system became operational in July 1983 and currently
continues to operate when the well is pumped, which is typically during seasonal periods of peak demand.
The system was constructed with five towers, each with its own blower and sized to treat up to 1000 (ig/L
of VOCs. Well 12A typically operates at about 3,500 gpm and the flow is split among the five towers. In
2009, the City of Tacoma switched to using only three towers during operation to save on costs.
1.4.3.2 Soil Excavation
Excavation and disposal of contaminated filter cake and shallow soils in and around the Time Oil
Building was selected in the first ROD Amendment and again in Amendment #2. In 1986, Burlington
Northern excavated approximately 1,200 cubic yards of contaminated soils along the rail spur. An
additional 5,000 cubic yards of waste sludge (filter cake) from the oil recycling operations were excavated
as part of the SVE system construction in 1992.
During the remedial design investigation completed in 2010, a 14,280-gallon underground storage tank
(UST) was encountered on the Time Oil property; the UST and adjacent soils, including filter cake
material, were subsequently removed in 2011/2012. Due to differences in the type and concentrations of
contaminants in soil, the excavation area was divided into a northern and a southern area. Soil in the
southern area met RCRA Land Disposal Restrictions (LDRs). Soil in the northern area contained high
levels of VOCs and required chemical treatment prior to disposal. Sodium persulfate and lime were used
OU 1, Well 12A
13
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to reduce VOCs to levels that met RCRA LDRs. Final quantities removed included 6,775 gallons of UST
liquids and 2,093 tons of contaminated soil. The final extents of the excavation are shown on Figure 2-3.
1.4.3.3 Groundwater Extraction and Treatment System
The first ROD Amendment selected a GETS consisting of extraction well(s) at the source area, treatment
of the extracted water by aeration, and discharge of the treated water to Commencement Bay. Treatment
was later changed to carbon adsorption in the April 28, 1987 memorandum to the Regional Administrator,
before the GETS system began operation in 1988. The overall objective of the GETS has been to limit
migration of dissolved contaminants in groundwater.
The GETS system as originally installed in November 1988 consisted of one well (EW-1) designed to
extract water at 500 gpm, although the maximum pumping rate recorded during initial operation was only
300 gpm. Sustained pumping rates at EW-1 significantly declined due to biofouling and in 1995, four
additional extraction wells (EW-2 through EW-5) were added to the system to augment extraction. Wells
EW-2 through EW-5 were designed to yield 50 gpm each, although maximum sustained rates during
initial operation only ranged from 7.5-24 gpm. The treatment system consists of two bag filters arranged
in parallel that precede two 20,000-pound granular activated carbon (GAC) units arranged in series.
Effluent is discharged via storm drains to the Thea Foss Waterway which flows into Commencement Bay.
The GETS extraction well locations are shown on Figure 2-4.
1.4.3.4 Soil Vapor Extraction
The SVE system was instituted after the first ROD Amendment under authority granted by the EPA
Regional Administrator. In August 1993, an SVE system was installed and began operation. The system
consisted of 22 vapor extraction wells in the area where drum storage and disposal operations had
previously occurred west of the Time Oil building. Vapors were treated using carbon adsorption.
Operation of the SVE system was discontinued in 1997 after soil contamination was reduced to
concentrations that would not impact groundwater quality along the west side of the Time Oil building
(EPA, 2009). 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 consisted of light-end
hydrocarbons. The SVE equipment is still on site, but it is in poor condition due to not being used or
maintained since it was shut down in 1997.
1.4.3.5 In-Situ Thermal Remediation
ROD Amendment #2 selected ISTR to treat the highly impacted portions of the deep vadose zone and
upper saturated zone near the former Time Oil building. Several phases of remedial design investigations
in 2010 and 2011 have been completed and the results used to delineate the area for ISTR. Data collected
during these and previous investigations were input into a 3D visualization model, Mining Visualization
Software by CTech (MVS), to determine contaminant distribution in soil and groundwater.
The proposed treatment area for ISTR was based on the modeled area containing COC soil concentrations
greater than 5,000 (.ig/kg. This area is approximately 13,150 square feet in size and extends from the
ground surface to a depth of 55 feet (see Figure 2-5). The majority of the mass is contained in two zones,
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South Tacoma Channel Superfund Site Five-Year Review
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0 to 10 feet bgs and 35 to 55 feet bgs. Approximately 77% of the proposed treatment area is located
beneath the Time Oil building, which will require removal of a portion of the building as described in the
2012 ESD. The most recent schedule indicates design of the ISTR remedy in 2013 with implementation
in 2014.
1.4.3.6 Enhanced Anaerobic Biodegradation
ROD Amendment #2 selected EAB to treat the high-concentration groundwater plume through injection
of a carbon substrate to enhance reductive dechlorination under anaerobic conditions. Treatment will be
targeted along the interface of the Qpf silt unit, where high concentrations of residual contamination
remain. The EAB remedy is still in the early stages of design. A bench-scale study was completed in 2012
that recommended general biodiesel waste oil or Inland Empire crude vegetable oil with bioaugmentation
(i.e., addition of cultured microorganisms). A shear-thinning fluid will be used for injections to increase
flow through the low permeability zones. A pilot-scale EAB test began in April 2013 to evaluate the
performance of the mixing and injection strategy. The final EAB remedy will be designed to achieve the
90% mass reduction RAO. EAB design will be completed in 2013 with implementation in 2014/2015.
1.4.3.7 Monitored Natural Attenuation
ROD Amendment #2 selected MNA as a contingency to implement once interim objectives have been
achieved and Tier 1 objectives have been met (i.e. 90% mass discharge reduction). Groundwater
monitoring will be used to determine if the GETS operation can be discontinued and MNA can be relied
on to achieve the long-term groundwater monitoring objectives of meeting cleanup levels in a reasonable
timeframe.
1.4.3.8 Groundwater Monitoring
ROD Amendment #2 selected groundwater monitoring as the means to determine if RAOs have been
achieved. Remedial performance monitoring will be used to evaluate the progress of ISTR and EAB
toward meeting Tier 1 objectives. Interim performance monitoring points will be used to determine when
Tier 2 objectives have been met (i.e. achieve cleanup levels at points of compliance). A 30-year
monitoring and evaluation program will be implemented to monitor remedial performance and determine
if Tier 3 objectives can be met in a reasonable timeframe (i.e. achieve cleanup levels throughout plume).
1.4.3.9 Institutional Controls
ROD Amendment #2 selected ICs to protect human health by limiting access to and future development,
improvement, and use of affected properties. An IC Plan was developed in 2010 describing ICs for the
site. The types of ICs selected include proprietary, such as restrictive covenants; governmental, such as
zoning ordinances, well drilling regulations, or local building/development permits; and informational
devices, such as EPA fact sheets. Following achievement of the Tier 1 objectives, soil and groundwater
contamination may still be present at levels above those that would be protective of human health and ICs
will be re-evaluated. A summary of the selected ICs and their current status is discussed in Section 1.6.7.
1.4.4. Systems Operations/Operations & Maintenance
Remedial activities with ongoing O&M are described below.
OU 1, Well 12A
15
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1.4.4.1
Well Head Treatment and Well 12A
The City of Tacoma owns and operates Well 12A and the five air stripping towers adjacent to the well.
When in operation, treated water from Well 12A is added to the drinking water supply. Well 12A and the
treatment system were used to meet peak summer demand throughout the 1980s and 1990s. Well 12A is
typically now pumped only during the summer or early fall on an every-other-year frequency for testing.
At the time of the site visit and the writing of this FYR, Well 12A was not being pumped to supplement
drinking water supply. A mechanic from the City visits the pump house on a weekly basis to check for
damage or tampering. In 2012, electrical panels that support the blowers on the air stripping towers were
upgraded; the communication system was simultaneously upgraded, which allows for remote operation
by the City. Vapor from the stripping towers is not treated with vapor phase carbon and is discharged to
the atmosphere. In 2009, the City switched from using all five air-stripper towers for treatment to using
only three to reduce the expense.
Since July 2006, the only COCs detected in influent to the treatment system have been TCE and trans-
1,2-DCE. Available influent (pretreatment) data is provided in Table 1-3. Effluent data was not available;
however, concentrations of COCs in the influent have remained below groundwater cleanup levels since
the 2009 sampling.
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South Tacoma Channel Superfund Site Five-Year Review
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Table 2-3. Well 12A Pretreatment data.
TCE
trans-l,2-DCE
Date
fag/L)
Gig/L)
9/20/1999
12.0
7/20/2000
8.5
10/24/2001
2.1
11/7/2002
2.5
Data unavailable
7/31/2003
7.7
10/19/2004
10.6
10/19/2005
3.1
7/26/2007
7.0
0.9
9/8/2008
0.80
ND
8/6/2009
4.2
0.58
9/23/2010
1.6
ND
6/29/2011
1.49
ND
6/6/2012
0.52
ND
1.4.4.2 Groundwater Extraction and Treatment System
The GETS system has been consistently operating, except for temporary shutdown periods for
maintenance. Sustained pumping rates have declined since the system was installed. Prior to well
rehabilitation in 2012, combined flows from the system were approximately 83 gpm. A GETS inspection
and performance evaluation was completed in August 2011. The inspection identified several deficiencies
that were later fixed, including replacement of pressure gauges, transducers, and the low-level switch at
well EW-1. Rehabilitation was also recommended for wells EW-1 and EW-2 due to their significant
decline in specific capacity. Rehabilitation was completed in 2012 using the Hydropuls© technology,
which uses bursts of compressed nitrogen along with extraction of groundwater to remove fines and
biofouling accumulated on the well screen and filter pack. Rehabilitation resulted in a substantial
improvement in extraction well yields and an increase in overall extraction rates by more than a factor of
2 (CDMSmith, 2012d).
Currently, only four extraction wells are in operation. The non-operating well, EW-4, is located adjacent
to the treatment area for ISTR and will be decommissioned as part of the ISTR remedy. A GETS capture
assessment was completed as part of the mass discharge evaluation (see Section 1.6.4.3) and it was
determined that well EW-3 was capable of maintaining full capture without EW-4 in operation. The
GETS has been shut down since April 2013 during the EAB pilot test and will most likely remain off
during the full-scale ISTR and EAB remedial activities.
The treatment system is located south of the Time Oil property outside on a concrete pad surrounded by a
chain-link fence. It consists of two bag filters arranged in parallel that precede two 20,0000-pound GAC
units arranged in series. Effluent from the second GAC unit is discharged to the City of Tacoma
stormwater system. Influent and effluent samples are collected bi-weekly by Tacoma Water personnel and
sent to EPA's Manchester Laboratory for analysis.
Between 1988 and December 2012, the GETS treated over 860 million gallons of groundwater, removing
approximately 18,625 pounds of VOCs (CDMSmith, 2012f). Influent concentrations of VOCs have
OU 1, Well 12A
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generally decreased from 2000 to 2009; however, contaminant concentrations observed in monitoring
wells remain elevated.
During the period of December 27, 2012, through March 7, 2013, cis-l,2-DCE, trans-1,2-DCE, and vinyl
chloride were the only chemicals that were detected in the discharge effluent from the GETS (Table 2-4).
Concentrations of cis-l,2-DCE, trans-1,2-DCE, and vinyl chloride ranged from non-detectto 0.53 (ig/L,
non-detect to 0.26 (ig/L and non-detect to 1.8 (ig/L, respectively. All three detected chemicals in the
effluent were present in concentrations below their respective MCLs of 70, 100, and 2 (ig/L. State water
quality standards for the protection of aquatic life are unavailable for the detected compounds although
federal National Toxics Rule water quality standards include a vinyl chloride concentration of 2 (ig/L for
the protection of human health due to the consumption of water and organisms.
Table 2-4. Recent GETS effluent data.
12/27/2013
1/10/2013
1/24/2013
2/7/2013
2/21/2013
3/7/2013
cis-1,2-DCE
0.32
0.53
0.42 J
0.34 J
0.33 J
LOU
trans-1,2-DCE
1.0U
0.26
LOU
LOU
LOU
LOU
PCA
1.0U
LOU
LOU
LOU
LOU
LOU
PCE
LOU
LOU
LOU
LOU
LOU
LOU
TCE
LOU
LOU
LOU
LOU
LOU
LOU
VC
1.3
1.7
1.7
1.8
1.8
LOU
All units are (.ig/L.
Previously, Ecology changed out the carbon when values in the effluent (from both vessels) reached 10
(ig/L for vinyl chloride (Chris Maurer interview, Appendix 1-D). This limit was based on empirical
observations of the system and is considered more stringent than the former operating criteria of 10.7
(ig/L for the sum of PCA and PCE; this limit is also well below the former discharge criteria proposed for
vinyl chloride of 100 (ig/L in the O&M manual (URS and CH2MHill, 2004). Using the 10 (ig/L guideline
value for vinyl chloride, Ecology determined that the typical carbon change-out frequency was twice per
year, which has replaced the vinyl chloride limit requirement and is now the standard.
1.4.4.3 Groundwater Monitoring
Since the remedies selected in ROD Amendment #2 are in progress, the current groundwater monitoring
program is focused on evaluation of remedial technology performance. Groundwater monitoring
objectives and wells to be sampled are determined for each sampling event based on the remedies
currently being implemented. Three rounds of monitoring have been completed since ROD Amendment
#2 was signed:
• Round 1, Fall 2011. The objective of this event was to fill data gaps in the CSM.
• Round 2, Summer 2012. The objective of this event was to fill data gaps in the CSM.
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South Tacoma Channel Superfund Site Five-Year Review
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• Round 3, December 2012. The objectives of this event were to evaluate passive sampling devices
and establish concentration trends in newly installed interim performance monitoring wells (IM
series).
The evaluation of the passive sampling devices during the third round of groundwater monitoring
concluded that the Hydrasleeve™ will provide adequate representation of subsurface conditions during
future performance monitoring events. Use of this sampling technology will decrease costs associated
with performance monitoring.
1.4.4.4 Summary of Costs of System Operations/O&M Effectiveness
Operating costs for Well 12A and the air stripping treatment system were unavailable from the City of
Tacoma. Since 2005, Tacoma Water has reduced the number of air-stripping towers in use from five to
three, resulting in significant electrical savings.
EPA contracted out the operation of the GETS from 1995 until operations were transferred to Ecology in
Fall 2005. Ecology pays Tacoma Water to operate, maintain, and sample the five extraction wells.
Ecology reports that the current costs are about $100,000 per year, which includes two carbon change-
outs ($40,000 per change out) and $20,000 for sampling performed by Tacoma Water personnel. EPA
resumed responsibility for O&M of the GETS in July 2013 for implementation of the ISTR and EAB
remedial activities.
1.5. Progress Since the Last Five-Year Review
1.5.1. Protectiveness statements from last review
The protectiveness statement from the 2008 Five-Year Review was the following:
The remedy at Well 12A is not protective because of the following issues:
• A potential threat is present from direct contact with remaining contaminated soils;
• Migration of the contaminated groundwater above the MCLs is not being controlled;
• Potential exposure to indoor air is likely. This exposure pathway requires evaluation to determine
if the remedy effectively minimizes risk of this exposure pathway.
• An ICP that considers remedy protectiveness ofpathways of concern should be developed to
prevent exposure to soil and groundwater contaminated above levels of concern;
• An effluent discharge permit is required to establish discharge criteria and point of compliance
requirements by which system O&M can be measured and potential exposure pathways from
discharge can be controlled; and
• Drums are present on site, which contain investigative derived wastes.
The following actions need to be taken to ensure protectiveness:
• Institutional controls should be developed and implemented to prevent direct contact to
remaining soil contamination;
OU 1, Well 12A
19
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• Additional information on the evaluation of source strength and current extent of current
groundwater plume should be collected. Once this information is obtained, an evaluation of the
remaining source area, impact on ability to achieve various targeted achievable RAOs for
groundwater, and potential remedy modifications shall be conducted via a focused feasibility
study which will screen remedial options in light of improving effectiveness of the remedy. ICs
should also be put into place preventing drinking water use;
• Evaluation of the indoor air pathway should be conducted and, if unacceptable risks are found,
they should be remedied;
• A discharge permit should be developed and finalized with the City ofTacoma; and
• Drums should be removed from the site.
1.5.2. Status of recommendations and follow-up actions from last review.
Recommendation 1: Use new 2008 groundwater data and pumping rates for extraction wells to establish
current site conditions and capture zones.
Status: Completed. Extensive groundwater monitoring data collected as part of the remedial design work
has significantly increased the understanding of current site conditions. A GETS capture zone analysis
was completed in 2012 to support the use of the extraction system for mass discharge calculations. An
aquifer performance test was also completed at Well 12A in 2012 to determine influence of pumping on
site remedies.
Recommendation 2: Conduct modeling to evaluate if indoor air pathway is complete.
Status: Not Completed. The Time Oil building occupants will not be present during the Tier 1 remedy
implementation. Only workers associated with the remedy implementation will be in the building.
USEPA will evaluate the indoor air pathway after achievement of Tier 1 objectives (i.e. 90% mass
discharge reduction) for future building use.
Recommendation 3: Identify potential viable RAOs and back calculate flux changes in source needed to
achieve them.
Status: Completed. ROD Amendment #2 (2009) identified six RAOs for the Site. A goal of at least 90%
contaminant discharge reduction was selected as the compliance level to achieve remedy complete status
for soil removal, ISTR, and EAB.
Recommendation 4: Compare potential RAOs to data needs to determine if additional soil or
groundwater data needed.
Status: Completed. Remedial design investigations were completed in 2010 and 2011. Numerous
monitoring wells and soil borings have been completed for use in the collection of data to fill data gap
obstacles to ISTR, EAB, and mass discharge flux measurements.
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South Tacoma Channel Superfund Site Five-Year Review
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Recommendation 5a: Conduct focused feasibility study to evaluate benefits of additional remedial
actions on ability toward achieving various RAOs. This evaluation should also include enhancements of
existing remedy, to include changes in existing extraction system and options for targeted source area
remediation.
Status: Completed. A Focused Feasibility Study evaluating additional remedial actions was completed in
April 2009. ROD Amendment #2 selected soil excavation, ISTR, and EAB as the additional remedial
actions.
Recommendation 5b: Generate decision document, as needed to document revised RAOs and or remedy
modifications.
Status: Completed. ROD Amendment #2, signed in 2009, revised the RAOs and selected final and
interim remedies for soil and groundwater, respectively.
Recommendation 6: Develop and implement ICs to prevent exposure to contaminated soil and
groundwater.
Status: Ongoing. An IC plan was completed in 2010. ICs are in place to prevent exposure to shallow soil
contamination and prevent ingestion of groundwater. However, additional environmental covenants may
be needed for future protectiveness. Following the achievement of Tier 1 objectives, ICs will be re-
evaluated.
Recommendation 7: Establish anew groundwater monitoring program, including pumping rates for
extraction wells, and well performance monitoring (dissolved oxygen, redox, biological characteristics,
etc.).
Status: Ongoing. A groundwater monitoring program has been implemented as part of the remedy
selected in ROD Amendment #2. Monitoring objectives are determined by event and are based on the
current active remedies. A GETS capture zone assessment was completed to determine the optimal
pumping rates for the mass discharge evaluation. Interim performance monitoring wells were in July-
August 2012; the location for the two new compliance wells has not yet been determined.
Recommendation 8: Establish a discharge permit, including discharge criteria and location of the point
of compliance.
Status: Not Needed. The substantive portions of the ARAR for GETS discharge need to be met (e.g.
discharge criteria); however, no Federal, State or local permits are required for the portion of any removal
action or remedial action at a CERCLA site. If GETS operations are resumed following EAB and ISTR
remedial actions, a discharge permit for treated effluent from the GETS including development of
discharge criteria and a point of compliance would need to be developed.. Detected chemicals in the
effluent for the period of December 27, 2012 thru March 7, 2013 included cis-l,2-DCE, trans-1,2-DCE,
and vinyl chloride. State aquatic life standards do not list these chemicals. All concentrations were below
available federal MCLs and water quality standards for the protection of human health.
OU 1, Well 12A
21
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Recommendation 9: Remove drums from the site.
Status: Completed. The drums identified during the last FYR site inspection were inventoried and
determined to be empty drums from previous drilling and well development. The drums were used to
contain investigation derived water (IDW) water prior to disposal using the GETS. Some of the drums
had collected rainwater and were mistakenly identified as containing IDW during the site inspection. EPA
disposed of drums with solids left on the bottom along with IDW from recent investigations. Those drums
in poor condition and not suitable for reuse were disposed of empty. Those drums in good condition were
reused for non-hazardous waste solids.
Recommendation 10: Complete the State Superfund Contract that will turn all site responsibilities over
to Ecology.
Status: Completed/Irrelevant. State Superfund Contract was signed in April 2010 however, this
recommendation does not impact the protectiveness of the remedy. ROD Amendment #2 developed
RAO compliance tiers that support a multi-component remedy and allow for decision making, such as
when to transition from one treatment technology to another and when to transfer O&M to the State.
Achievement of Tier 1, which includes a mass discharge reduction of 90% from the high concentration
source area, would trigger turning the site over to the State.
1.6. Five- Year Re view Process
1.6.1. Administrative Components
The USEPA Remedial Project Manager for the Well 12A project area is Howard Orlean. The five-year
review team included the following personnel from the USACE Seattle District: Heather Whitney
(chemist) and Sharon Gelinas (hydrogeologist). The review team established the review schedule to be
completed between January 2013 and May 2013. Components of the review included:
• Document Review
• Data Review
• Site Inspection
• Local Interviews
• Five-Year Review Report Development and Review.
1.6.2. Community Involvement
A public notice announcing the five-year review for the Site was published April 25, 2013 in the Tacoma
News Tribune.
1.6.3. Document review
This FYR included a review of relevant, project-related documents including RODs, ROD amendments,
one ESD, monitoring reports, investigation reports, and recent monitoring data. A complete list of the
documents reviewed can be found in Appendix 1-A.
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South Tacoma Channel Superfund Site Five-Year Review
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1.6.4. Data Review
Two phases of Remedial Design (RD) investigations have been completed since ROD Amendment #2
was signed in 2009. The original investigation was completed in 2010 and a follow-on phase was
completed in 2011. Along with the 2011 RD, a vertical profiling investigation was completed to support
the evaluation of the mass discharge. A total of 46 soil borings and 6 monitoring wells were installed
during the RD investigations along with collection of numerous soil and groundwater samples and
hydraulic conductivity data. Figure 2-6 shows the sampling locations and groundwater monitoring wells
at the site at the time of the RD investigations. Following the RD investigations, 6 interim performance
monitoring wells and 8 EAB wells were installed, which included 3 test injection wells. The additional
wells are shown on Figure 2-7.
The 3D visualization software MVS has been utilized throughout the project to evaluate the distribution
of soil and groundwater contamination and determine treatment zones for the multi-component remedy.
MVS can be used to interpolate geologic, hydrogeologic, and contaminant data. MVS uses geostatistical
analyses to determine contaminant extents and to evaluate confidence and uncertainty in outputs. Where
applicable, the results of the modeling are used to support the discussion below.
1.6.4.1 Soil
Soil contamination at the Well 12A project area remains in two source areas: the Time Oil source area
and the Qpf fine-grained unit source area. The primary source area is associated with the Time Oil source
which consists of filter cake and shallow soils impacted by residual dense non-aqueous phase liquids
(DNAPL). This shallow soil contamination is generally located from 0 to 10 feet bgs. The highest
concentration for the sum of the six COCs was detected at 1 foot bgs at a concentration of 462,000 (.ig/kg.
which is indicative of filter cake material. Residual contamination is also located within the deep vadose
zone beneath the former Time Oil building; the highest concentrations were located primarily between 30
and 50 feet bgs.
A fine-grained unit with high concentrations of COCs was identified to the southwest of the former Time
Oil building during the RD investigations. This unit, also called the Qpf fine grained unit, is thought to act
as a secondary source of contamination to groundwater. Contamination in the silt (fine-grained) unit was
typically encountered at 56 to 59 feet bgs; the highest concentration for the sum of the six COCs was
43,000 (ig/kg.
Elevated COC soil concentrations were also encountered at the base of the upper aquifer near South
Tacoma Way during the RD investigations. For the sum of the six COCs concentrations up to 9,430 j^ig/kg
were detected.
Figure 2-8 shows the MVS model results for soil contaminant distribution split into four zones. These
zones are used to discuss mass distribution and identify remedies. Zone A represents a shallow potential
secondary source southwest of the Time Oil building where elevated VOCs were encountered. It was
determined that the contaminant mass in Zone A does not appear to be a secondary source and there is no
remedy planned to treat contamination in this zone. Zone B represents the Qpf fine-grained unit source
area and soil contamination at the base of the upper aquifer. EAB will be used treat contamination in this
OU 1, Well 12A
23
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zone. Zone C represents the vadose zone contamination beneath the former Time Oil Building and Zone
D represents the saturated zone contamination beneath the former Time Oil Building. Excavation of
shallow contaminated soil to the east of the Time Oil Building has removed some of the mass in Zone C;
ISTR will target the remaining contamination in Zones C and D.
1.6.4.2 Non-Aqueous Phase Liquid
Both light non-aqueous phase liquid (LNAPL) and DNAPL (dense NAPL) have been identified at the
site. LNAPL primarily exists in the smear zone near the water table where it partially fills voids in the
soil. Wells TOW-6, TOW-7, EW-4, MW-1 and MW-3 have had historical detections of LNAPL (Figure
2-6). DNAPL is evidenced by high concentrations of VOCs in soils at depth. DNAPL was found in
monitoring well EAB-1 installed as part of the EAB pilot study.
1.6.4.3 Groundwater
Groundwater flow in the project area is influenced by several factors including operation of the GETS and
operation of the Tacoma Water production wells. Under regional, non-pumping, conditions, groundwater
flow is toward the east and northeast. When the GETS is operating, flow is generally toward the
extraction wells. The GETS has the strongest influence in the shallow and medium zones of the upper
aquifer where the gradient reverses direction. In the base portion of the upper aquifer, the GETS has
minimal influence; the flow direction remains the same, but the gradient decreases by about half. The
strong downward vertical gradient typically observed in upper aquifer wells at the Site increases when the
GETS is in operation. Figure 2-9 depicts the groundwater flow direction with and without the GETS in
operation.
An aquifer performance test was completed in 2012 using Well 12A to evaluate the influence of pumping
on site remedial actions. The test concluded that the radius of influence of Well 12A extends
approximately 2,300 feet northward toward the former Time Oil building and drawdown influence is
estimated to be less than 0.6 feet. When Well 12A and the GETS are both operating, the GETS maintains
hydraulic control near the former Time Oil building, while groundwater south of South Tacoma Way
flows toward Well 12A. The lower portion of the upper aquifer was assumed to be semi-confined to
confined for the analysis. Hydraulic conductivities were calculated as 874 to 5,921 ft/day and storage
coefficients ranged from 0.006 to 0.078.
Results from groundwater sampling completed during the RD investigations were used to determine the
extent of the high-concentration dissolved-phase plume. Figure 2-10 shows the extent of the high-
concentration plume where the sum of the six COCs is greater than 300 (ig/L. This area is largely
anaerobic and intrinsic anaerobic attenuation is occurring; however, not at rates that would achieve RAOs
within a reasonable timeframe. All six COCs have been detected at concentrations above ROD cleanup
levels during the RD investigations. PCE was the most prevalent COC detected throughout the plume;
however, cis-l,2-DCE and trans-l,2-DCE also represent a significant portion of mass within the plume.
Mass discharge is being used as the performance metric for completion of remedial actions in the high-
concentration source areas. As part of the remedial design, a detailed analysis of mass discharge
measurement methods was completed. Two methods were evaluated: the transect method and the
24
South Tacoma Channel Superfund Site Five-Year Review
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pumping test method. The 2011 RD investigation included a vertical profiling investigation along two
transects, one to the north and one to the south of South Tacoma Way, for use in evaluating mass
discharge. Groundwater samples collected from multiple levels within the aquifer and slug testing
completed in representative intervals were used to integrate concentration and flow data along the
transect. The pumping test method using the GETS was also evaluated. This method relies on extracting
groundwater at a constant rate and measuring the flow and mass discharges from the wells. A GETS
capture zone analysis was completed to determine the optimal pumping rates and whether a representative
portion of the plume would be captured. The optimal pumping rate was a combined total of 134 gpm with
complete capture expected in 180 days or less. This optimum pumping rate is an improvement over the
pre-rehabilitation rate of 83 gpm using all five extraction wells.
The pumping test method was selected as the preferred mass discharge measurement method. Data
analysis methods were then developed to limit uncertainty and account for variability in flow rates,
sampling, and analysis. Eight rounds of mass discharge measurements were collected between September
2012 and January 2013 (see Figure 2-11). The last three measurements indicated that stabilization was
achieved and the average of these three measurements, 403 g/day, was agreed on as the baseline mass
discharge measurement.
1.6.5. Site Inspection
A site inspection was conducted on March 6, 2013. Personnel from US ACE, CDMSmith, and City of
Tacoma attended. Details of the site inspection and photos are presented in Appendix 1-B. The
completed inspection checklist is presented in Appendix 1-C.
The GETS system and associated extraction wells were observed to be in working condition during the
site inspection. Fencing around the GETS and the associated office/storage trailer was intact.
The former Time Oil property use was confirmed to be commercial and industrial. The site was
completely paved, with the exception of the former warehouse east of the former East Tank Farm. The
former SVE building is used as office and storage space for current remedial design activities.
The Well 12A wellhead treatment system was not in operation during the site visit, but all components,
electrical structures, and fencing appeared in good condition.
1.6.6. Interviews
Interviews were conducted with the following agencies/organizations:
• City of Tacoma (Tacoma Water branch of Tacoma Public Utilities) - Chris Johnson and Craig
Downs;
• Washington State Department of Ecology - Chris Maurer, Project Manager
• Citizens for a Healthy Bay (CHB) - Leslie Ann Rose, Senior Policy Analyst
Craig Downs also provided City production well data. The full questionnaire responses are presented in
Appendix 1-D.
OU 1, Well 12A
25
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In general, Ecology and the City of Tacoma were pleased with the progress at the Well 12A project area.
The only complaint expressed by the City was the slight nuisance caused by the need to turn Well 12A
and the GETS wells on and off as needed for the pumping tests. However, the contractor (CDMSmith)
was reportedly doing a good job of providing information and pumping needs with enough advance
notice to the City. As the cost of operating the treatment system is an increasing concern for the City, the
City would like to see the cleanup completed so the treatment system can be shut down permanently.
Leslie Ann Rose of CHB was not up-to-date on current progress, stating that the last information received
occurred 3-4 years ago during the ROD. She specifically requested that regular communications from
EPA be established so that CHB can stay informed regarding current work on the Site.
1.6.7. Institutional Controls
An IC plan was developed in 2010 that selected ICs for the protection of human health. A title search was
not completed as part of this FYR because EPA had recently completed a title search prior to the
development of the IC plan in 2010. EPA has obtained access agreements from property owners where
investigation work was completed and will obtain additional access agreements, as necessary, for
implementation of remedial activities. In addition, six parcels, including the Time Oil property and
adjacent properties, have proprietary controls in place to allow unencumbered access for purposes of
remedial action activities.
A summary of the ICs and their status follows:
ICs to prevent human exposure to shallow soil contamination:
• Environmental covenants for use restrictions. Shallow soil contamination was identified at three
parcels at the time the IC plan was developed. This IC has not been implemented and will be re-
evaluated following the achievement of Tier 1 objectives.
• Construction permits are required to regulate excavation on affected properties. Tacoma
Municipal Code 13.09.080 requires a permit before "constructing, installing, substantially
modifying, or changing the use of a facility or regulated facility." All properties affected by the
soil contamination are within the South Tacoma Groundwater Protection District. TPCHD is
responsible for regulating pollution prevention in this District and utilizes institutional knowledge
of the existing contamination at Well 12A to preclude construction permitting. This IC is
currently in place.
• Land use zoning to prevent residential development and uses. Properties where soil
contamination has been identified are currently located within the City of Tacoma zoning district
M2 (heavy industrial). This IC is currently in place; the M2 boundary was verified as part of this
FYR.
• List on a state register. The former Time Oil property is listed on the State of Washington's
Confirmed and Suspected Contaminated Sites List (CSCL) and the State's Hazardous Sites List.
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South Tacoma Channel Superfund Site Five-Year Review
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This IC is currently in place; the Well 12A project area was verified on the CSCL as part of this
FYR. The need to list adjacent/nearby properties with remaining soil contamination should be
evaluated following achievement of Tier 1 objectives.
ICs and engineering controls to prevent human exposure to contaminated groundwater by preventing
ingestion of contaminated groundwater:
• Operation of air stripping towers when Well 12A is in operation will be used to reduce
contaminant concentrations to levels below water quality standards. This is an engineering
control operated by Tacoma Water and is currently in place.
• Development of a pumping agreement among EPA, Ecology, and Tacoma Water to coordinate
pumping and implementation of the remedy so that operation of Well 12A does not disrupt
certain phases of the remedy. This IC is currently in place; the agreement was signed in
December 2010. Coordination meetings are conducted annually as required by the agreement.
• Well permitting process. According to communications with Sharon Bell of TPCHD, drinking
water well installations are currently not allowed within the City of Tacoma because it is a
municipal service area. TPCHD is very aware of the problems with the Time Oil site and not
likely to consider a well installation in that vicinity for drinking water purposes. Washington
State regulations (WAC-1732-160-171) also prohibit installation of any drinking water wells
within or near known or potential sources of contamination.
ICs to support long-term monitoring after completion of the active remedy:
• Environmental covenants for properties where wells are located. Re-evaluation of this IC and the
need for environmental covenants will be completed following the development of a long-term
groundwater monitoring program. According to April 2013 parcel access agreement information
available from CDMSmith, 25 parcels are currently located above or adjacent to the 300-ppm
COC groundwater plume.
• A long term monitoring agreement among EPA, Ecology and Tacoma Water to identify roles,
responsibilities, and communication strategy during monitoring. This IC will be completed
following the development of a long-term groundwater monitoring program.
OU 1, Well 12A
27
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1.7. Technical Assessment
1.7.1. Question A: Is the remedy functioning as intended by the decision
documents?
Yes. Construction of the remedial actions described in ROD Amendment #2 is still in progress and the
remedy is expected to be protective upon completion. Shallow soil contamination to the east of the Time
Oil building has been excavated and transported off-site for disposal. ISTR and EAB are still in the design
phase and are scheduled to be complete by 2015. In the interim, the GETS continues to operate and
remove dissolved-phase contaminants in the high-permeability zones and Welll2A water is treated via air
stripping prior to use for drinking water. ICs are in place to prevent exposure to shallow soil during
remedial activities and to prevent ingestion of groundwater.
Remedial Action Performance
Progress had been made toward achieving the Tier 1 objective of a 90% reduction in mass discharge.
Shallow soil contamination to the east of the former Time Oil building, along with a UST discovered
during the RD investigation, was excavated in 2011/2012. The area for the planned ISTR treatment,
beneath and adjacent to the former Time Oil building, has been defined; system design and
implementation is scheduled to be complete in 2014. Pilot studies for EAB are being conducted; design
and implementation of full-scale EAB is scheduled to be complete in 2015. A mass discharge
measurement method has been selected and the baseline measurement, 403 g/day, has been determined.
Performance monitoring has been focused on filling data gaps in the CSM and baseline monitoring of
newly installed wells. As the ISTR and EAB remedies progress, monitoring will focus on the
performance of these activities. Objectives for monitoring are currently determined on a per-event basis.
System Operations/O&M
The air-stripper treatment system at Well 12A is currently working as designed. The air strippers have
been in operation since 1983. Electrical and communication systems were upgraded in 2011/2012, but no
other major repairs have occurred. Currently, only three of the five air stripping towers are utilized to treat
groundwater, resulting in significant cost savings. All treated groundwater meets MCLs.
The GETS system has recently been repaired to keep it in working condition for use throughout the
remedial actions, if necessary. Inspections identified several deficiencies, such as the need for
replacement of pressure gauges, transducers, and a switch at EW-1, that were subsequently fixed.
Rehabilitation of extraction wells EW-1 and EW-2 was recommended due to their decline in specific
capacity. Rehabilitation was completed in 2012 using the Hydropuls© technology. Well EW-4 is no
longer in operation since it will be decommissioned during the implementation of ISTR. Capture zone
analyses determined that well EW-3 is capable of maintaining full capture without the use of EW-4. The
optimal total pumping rates using four extraction wells determined during the mass discharge
28
South Tacoma Channel Superfund Site Five-Year Review
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measurements was 134 gpm, which is an improvement over the pre-rehabilitation rate of 83 gpm using all
five extraction wells.
Opportunities for Optimization
An evaluation of passive samplers was completed during the last groundwater monitoring event. It was
concluded that Hydrasleeve™ samplers can provide adequate representation of the subsurface condition
and will be used in future performance monitoring to reduce costs.
Implementation of Institutional Controls
An IC plan was developed in 2010 that selected controls for the protection of human health. ICs to
prevent human exposure to shallow soil contamination include environmental covenants and
governmental controls (e.g. construction permits, zoning restrictions, and listing of the site on the State of
Washington's Confirmed and Suspected Contaminated Sites List [CSCL]). ICs to prevent ingestion of
contaminated groundwater include pumping agreements with Tacoma Water and TPCHD's well
permitting process. ICs to support long-term monitoring will include environmental covenants or access
agreements and a long-term monitoring agreement among EPA, Ecology, and Tacoma Water. Fact sheets
will be used to keep citizens informed throughout implementation of the remedy.
ICs associated with governmental controls are currently in place. The project area is located within the
South Tacoma Groundwater Protection District, where pollution prevention is regulated by TPCHD.
TPCHD also has several other controls in place to prevent drinking water wells from being installed.
Following the achievement of Tier 1 objectives, ICs will be re-evaluated and proprietary controls, such as
environmental covenants, will be implemented.
Early Indicators of Potential Issues
There are no indicators of potential issues.
1.7.2. Question B: Are the exposure assumptions, toxicity data, cleanup levels,
and remedial action objectives (RAOs) used at the time of the remedy
selection still valid?
No. There have been some changes to toxicity values that may require future re-evaluation of selected
cleanup levels to ensure protectiveness is maintained. The changes do not affect the current protectiveness
since ICs are in place to prevent exposure above the new standards. In addition, these changes do not
affect the achievement of the Tier 1 criteria, a 90% reduction in mass discharge.
Changes in standards and to-be-considered criteria (TBCs)
Table 2-5 presents the chemical-specific numerical standards selected in Amendment #2 to the ROD
(USEPA, 2009). The selected groundwater cleanup levels are applicable only at the Points of
Compliance, which are defined in Amendment #2 as Well 12A and compliance wells CW-1 and CW-2.
OU 1, Well 12A
29
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Interim performance monitoring wells were installed in July and August 2012; the locations for the two
compliance wells have not yet been determined.
Table 2-5 presents all standards in the ROD, as of Amendment #2. MCLs were selected as the cleanup
levels for cis- and trans-1,2-DCE. There have been no changes to the MCLs since ROD Amendment #2.
Since ROD Amendment #2, revisions to Model Toxics Control Act (MTCA) B1 cancer and/or non-cancer
values have occurred for cis-1,2-DCE, PCE, TCE, and vinyl chloride. The impact of the revisions for
each of the COCs is discussed in more detail below.
Cis-1,2-DCE. The MCL (70 (ig/L) was selected as the cleanup level for cis-l,2-DCE. However, since the
2009 ROD Amendment #2, the MTCA B non-cancer value has decreased from 80 to 16 (ig/L. The
selected cleanup level (70 j^ig/L) is greater (less stringent) than the current MTCA B non-cancer value (16
(ig/L). The change in the MTCA B standard does not affect the current protectiveness since ICs are in
place to prevent exposure above the new MTCA B non-cancer standard of 16 (ig/L..
Trans-1,2-DCE. The MCL (100 ug/L) was selected as the cleanup level for trans-1,2-DCE in ROD
Amendment #2. Since then, the MCL has not changed, no current MTCA B cancer standard is available,
and the current MTCA B non-cancer standard of 160 ug/L is less stringent than the MCL.
PCA. ROD Amendment #2 selected the MTCA B cancer standard of 0.2 ug/L as the cleanup level for
1,1,2,2-PCA. The MTCA B cancer value has not changed since ROD Amendment #2. The MTCA B non-
cancer standard (160 ug/L) remains above (less stringent). No MCL was or is currently available for PCA.
PCE. In September 2012, the MTCA B cancer value increased to 21 (ig/L and a new non-cancer value
(48 (ig/L) was established. The selected cleanup level of 0.8 (ig/L (based on MTCA B at 10"5 cancer risk
level) is now more protective. The MCL (5 (ig/L) is more stringent than the MTCA B values.
TCE. In September 2012, the TCE MTCA B cancer value increased from 0.49 to 0.54 (ig/L (10~6 risk)
while the MTCA B non-cancer value increased from 2.4 to 4 (ig/L. The MCL (5 (ig/L) did not change. At
the time of the 2009 ROD Amendment #2, the selected GW cleanup level was the MTCA B non-cancer
value, which was the lowest value among the MTCA B cancer (10 5 risk) and non-cancer values and the
MCL. Given these revisions, if the groundwater cleanup were selected today, the MTCA B non-cancer
value would still be the lowest of the three values, but the value would be 4 (ig/L. Thus, the selected
groundwater cleanup level of 2.4 (ig/L is still protective.
Vinyl chloride. The MTCA B cancer value for vinyl chloride has undergone two revisions since the ROD
Amendment #2, but the overall effect is that the value has not changed and the revisions therefore do not
affect protectiveness.
The ROD and subsequent amendments does not identify specific cleanup concentration standards for site
soil contamination. For groundwater, ROD Amendment #2 requires a contaminant discharge reduction of
1 MTCA B values were obtained on 2/14/2013 via Ecology's online Cleanup Levels and Risk Calculations
(CLARC) database (https://fortress.wa.gov/ecy/clarc/CLARCHome.aspx).
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South Tacoma Channel Superfund Site Five-Year Review
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at least 90% from the high-concentration source area near the Time Oil building to the dissolved-phase
contaminant plume (RAO #1). Soil removal, ISTR, and EAB will be considered complete and the remedy
will be considered operational and functional when this criteria has been met. This cleanup goal is
specific to the project area and is not affected by changes in published numerical cleanup standards.
OU 1, Well 12A
31
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Table 2-5. Summary of Groundwater ARAR Changes
Contaminant of
Concern
MTCA Method B (ingestion
+ inhalation) as provided in
2009 ROD
Hg/L
MCL at time
of 2009 ROD
Ground-
water
Cleanup
Level
(ms/l)
Basis for Cleanup
Level
Current Regulations
Change since
2009 ROD?
Non-cancer
MTCA B
Cancer 10"6
MTCA B
Non Cancer
MCL
cis-1,2-DCE
70a
NP
70
70
MCL
NA
16
(revised
downwards from
80 (ig/L on
4/13/2011 based
on updated
toxicity values)
70
Yes. MTCA B
non-cancer is now
more stringent than
selected GW
cleanup level.
6ȤfF,2-DCE
100a
NP
100
100
MCL
NA
160
100
No revisions
found.
1,1,2,2-PCA
0.2
NP
NA
0.2
MTCA B 10"6
(no MCL)
0.22
160
NA
No revisions
found.
PCE
0.08
NP
5
0.8
MTCA B 10^
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Table 2-6. ARARs Analysis
ROD
Authority
ARAR / Citation
ARAR
Determination
Standard Applied in ROD
Current Use/ Changes
2009 ROD
Amendment
#2
Hazardous Waste
Cleanup - Model
Toxics Control Act
(MTCA) of 1989,
RCW 70.105D
MTCA, WAC 173-340 (as
amended Nov 2007). Specific
subsections:
WAC 173-340-720
WAC 173-340-740
WAC 173-340-745(b)
WAC 173-340-747
WAC 173-340-440(1-4,9)
Applicable
Establishes the process and
methods used to evaluate risk and
develop standards for soil and
other environmental media.
The substantive requirements of the specified
subsections are relevant and appropriate to developing
cleanup standards for the selected remedy: MTCA
method B levels as the cleanup levels for TCE, 1,1,2,2-
PCA, PCE, and VC. Revisions have occurred for PCE,
TCE, and vinyl chloride. None of the revisions
adversely affect the protectiveness of the selected
remedy.
2009 ROD
Amendment
#2
Safe Drinking
Water Act of 1974,
42 USC 300 et seq.
National Primary Drinking
Water Standards, Subpart G,
Specific subsections:
40 CFR 141.61,
40 CFR 141.62
40 CFR 141.66
Relevant and
Appropriate
Establishes maximum contaminant
levels for drinking water.
The selected remedy is using the MCLs for 1,2-cis-DCE
and 1,2-trans-DCE. There have been no revisions to the
federal MCLs for these chemicals.
2009 ROD
Amendment
#2
Washington Clean
Air Act (CAA) of
1967, RCW 70.94
and RCW 43.21 A
"State Government
- Executive"
General Regulations for Air
Pollution Sources, WAC 173-
400
Specific subsections:
WAC 173-400-040
Applicable
Requires all sources of air
contaminants to meet emission
standards for visible, particulate,
fugitive, odors, and hazardous air
emissions. Requires use of
reasonably available control
technology.
Applicable to remedial actions at OU1 due to the
generation of fugitive dust that will occur during
construction activities.
General revisions occurred in March 2011, Aug 2011,
Nov 2012 to bring the rule into compliance with USEPA
regulations. Any revisions do not affect protectiveness.
2009 ROD
Amendment
#2
Washington CAA,
RCW 70.94 and
RCW 43.21 A
Specific subsection:
WAC 173-400-113
Applicable
Requires controls to minimize the
release of air contaminants
resulting from new or modified
sources of regulated emissions.
Emissions are to be minimized
through application of best
available control technology.
Waste generated for disposal that does not meet
Environmental Restoration Disposal Facility waste
acceptance criteria, will require the use of a treatment
technology (e.g., to treat generated waste to meet
disposal facility acceptance requirements) that may emit
regulated air emissions. If such treatment is required,
this requirement would be applicable.
General revisions occurred in March 2011, Aug 2011,
Nov 2012 to bring the rule into compliance with USEPA
regulations. Any revisions do not affect protectiveness.
Controls for New sources of
Toxic Air Pollutants, WAC
173-460
Specific subsections:
WAC 173-460-030
WAC 173-460-060
WAC 173-460-070
Applicable
Requires specific controls for new
regulated air emissions.
Although unlikely, the selected remedy may require use
of a treatment technology (e.g., to treat generated waste
to meet disposal facility standards) that emits toxic air
emission. If such treatment is required, this requirement
would be applicable. There have been no revisions that
affect protectiveness.
OU 1, Well 12A
33
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ROD
Authority
ARAR / Citation
ARAR
Determination
Standard Applied in ROD
Current Use/ Changes
2009 ROD
Amendment
#2
Hazardous Waste
Management Act
of 1985, RCW
70.105
Dangerous Waste Regulations,
WAC 173-303
Specific subsections:
WAC 173-303-016
WAC 173-303-017
WAC 173-303-070(3)
WAC 173-303-073
WAC 173-303-077
WAC 173-303-170(3)
Applicable
Specifies how to identify
dangerous waste. Establishes the
management standards for solid
wastes that designate as dangerous
wastes.
Applicable to identifying solid and dangerous wastes
generated during OU remedial actions. The management
standards are applicable to the management and disposal
of those wastes identified as dangerous waste. There
have been no revisions that affect protectiveness.
2009 ROD
Amendment
#2
Hazardous Waste
Management Act
of 1985, RCW
70.105
Dangerous Waste Regulations,
WAC 173-303
Specific subsection:
WAC 173-303-140
Applicable
Identifies dangerous wastes that are
restricted from land disposal,
describes requirements for state-
only-restricted wastes, and
prohibits land disposal of restricted
wastes unless treatment standards
have been met. Incorporates
Federal land disposal restrictions
including provisions for treatability
variances by reference.
Applicable to the disposal of dangerous waste that will
be generated during implementation of the selected
remedy.
There have been no revisions that affect protectiveness.
2009 ROD
Amendment
#2
Solid Waste
Management,
Recovery, and
Recycling Act of
1969, RCW 70.95
Nondangerous Non radioactive
Solid Waste Management,
WAC 173-304 and 173-351
Specific subsections:
WAC 173-304-190
WAC 173-304-200
WAC 173-304-460
Applicable
Establishes requirements for the
management of solid waste.
Applicable to the onsite management and disposal of
solid waste that will be generated during implementation
of the selected remedy. There have been no revisions
that affect protectiveness.
2009 ROD
Amendment
#2
Water Well
Construction,
RCW 18.104
Minimum Standards for
Construction and Maintenance
of Water Wells, WAC 173-160
Rules and Regulations
Governing the Licensing of
Well Contractors and
Operators, WAC 173-162
Applicable
Establishes minimum standards for
design, construction, capping,
scaling, and decommissioning of
wells. Establishes qualifications for
well contractors and operators.
Applicable to the installation of wells that will be
required for groundwater extraction/injection and
monitoring. Any revisions do not affect protectiveness.
2012 ESD
Clean Air Act,
National Emission
Standards for
Hazardous Air
Pollutants
(NESHAPs)
Standard for demolition and
renovation (40 CFR 61.145)
May be
relevant and
appropriate
The CAA regulates any activities
(e.g. demolition or renovation) that
may result in the release of
airborne asbestos.
Time Oil Building has not yet been demolished.
Presence of asbestos-containing materials (ACM) is
unknown. There have been no revisions since the ESD.
2012 ESD
Washington Clean
Air Act, 70.94
Revised Code of
Washington
(RCW)
Puget Sound Clean Air
Agency, Asbestos Control
Standards (Regulation III)
Will be
considered
The Time Oil Building may
contain asbestos. Asbestos Control
Standards related to demolition
which are administered by PSCAA
will be considered.
Time Oil Building has not yet been demolished.
Presence of asbestos-containing materials (ACM) is
unknown.
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South Tacoma Channel Superfund Site Five-Year Review
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Changes in Exposure Pathways
Table 2-7 presents the exposure pathways identified in the 1985 first ROD Amendment, the 2009
ROD Amendment #2, and the 2012 ESD. Risk estimates were provided in the 1985 first ROD
Amendment.
Table 2-7. Exposure Pathways
Source
Exposure Scenario & Pathway
Risk Estimate
Reference
Contaminated soil
Inhalation
10-3 to 10-6
1985 ROD
Amendment #1
Soil Ingestion
Soil Direct Contact
Contaminated Groundwater
Groundwater Ingestion
10"4
The exposure pathways for soil and groundwater presented in the RODs have not changed. Much of
the project area is paved or covered with concrete, thus limiting the occupants' exposure to surface
soil. Soil and groundwater remediation is not yet complete. No new or changed human health or
ecological routes or receptors have been identified.
EPA's understanding of contaminant migration from soil gas and/or groundwater into buildings has
evolved over the past few years, leading to the conclusion that vapor intrusion may have a greater
potential for posing risk to human health than assumed when the ROD(s) were prepared.
Contaminated groundwater underlies at least one business. The 2009 FFS included a vapor intrusion
screening level analysis that concluded that further investigation for vapor intrusion may be warranted.
According to the 2009 ROD Amendment #2, vapor intrusion will be evaluated after completion of the
ISTR and EAB activities.
Changes in land use
Current land use has not changed since the ROD(s). The current and reasonably anticipated future land
use on and around the former Time Oil property and Well 12A is commercial/industrial. The current
and potential future beneficial use for groundwater is drinking water. Well 12A is currently used by
the city of Tacoma for municipal water supply. It is anticipated that future use of Well 12A will
increase due to increased demand for the Tacoma municipal water supply. No changes in land use or
groundwater are anticipated in the future near Well 12A and the former Time Oil Site.
Changes in Toxicity and Other Contaminant Characteristics
EPA's Integrated Risk Information System (IRIS) updates toxicity values used by the Agency in risk
assessment when newer scientific information becomes available. In the past five years, there have
been a number of changes to the toxicity values for all but one COC at the Site. Revisions to the
toxicity values for cis-l,2-DCE, PCE, and TCE indicate a higher risk from exposure to these
chemicals than previously considered. Table 2-8 lists the new toxicity values.
OU 1, Well 12A
35
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Table 2-8. Toxicity Value Changes
Contaminant
Toxicity values in ROD1
Changes in Toxicity Values2
Date of
Revision
Cis-1,2-DCE
Oral RfD: 1E-2 mg/kg-day
Inhalation RfC: 1E-2 mg/kg-day
Oral RfD: 2E-3 mg/kg-day
Inhalation RfC: No value
09/2010
Trans- 1,2-DCE
Oral RfD: 2E-2 mg/kg-day
Inhalation RfC: 2E-2 mg/kg-day
Oral RfD: No change.
Inhalation RfC: 6.0E-2 mg/m3
09/2010
1,1,2,2-PCA
Oral RfD: 6E-2 mg/kg-day
Inhalation RfC: 6E-2 mg/kg-day
Oral SF: 2E-1 (mg/kg-day)"1
Inhalation SF: 2E-1 (mg/kg-day)"1
Oral RfD: 2E-2 mg/kg-day
Inhalation RfC: No value.
Inhalation RfC: No value
IUR: 5.8E-5 (jig /m3)"1
09/2010
PCE
Oral RfD: 1E-2 mg/kg-day
Inhalation RfC: 1E-2 mg/kg-day
Oral SF: 5.4E-1 (mg/kg-day)"1
Inhalation SF: 2.1E-2 (mg/kg-day)"1
Oral RfD: 6E-3 mg/kg-day
Inhalation RfC: 4E-2 mg/m3
Oral SF: 2.1E-3 (mg/kg-day)"1
IUR: 2.6E-7(|ig/m3)"1
02/2012
TCE
Oral RfD: 3E-4 mg/kg-day
Inhalation RfC: 1E-2 mg/kg-day
Oral SF: 4E-1 (mg/kg-day)"1
Inhalation SF: 4E-1 (mg/kg-day)"1
Oral RfD: 5E-4 mg/kg-day
Inhalation RfC: 2E-3 mg/m3
Oral SF: 4.6E-2 (mg/kg-day)"1
IUR: 4.1E-6 (ng/m3)"1
09/2011
Vinyl Chloride
Oral SF: 7.2E-1 (mg/kg-day)
IUR: 4.4E-6 (jig /m3)-l
Oral RfD: 3E-3 mg/kg-day
Inhalation RfC: 1E-1 mg/m3
No changes since ROD.
08/2000
(No
changes
since ROD)
1 - Toxicity values were not provided in the RODs. Therefore, this evaluation uses the 2004 Preliminary Remedial Goals
(PRGs) from EPA Region 9.
2 - New toxicity values are from the November 2012 EPA regional screening levels (RSLs) which reflect the most recent
EPA IRIS toxicity values; different units for inhalation toxicity values have been published, as EPA no longer uses
inhalation reference doses or inhalation cancer slope factors, but rather inhalation reference concentrations and inhalation
unit risks. MTCA equations continue to use the older units. These toxicity values are used to determine all screening and
cleanup levels.
C - Cancer; IUR - inhalation unit risk ; NC - non-cancer; RSL - regional screening level; RfD -reference dose; RfC -
referemce concentration; SF - slope factor.
Groundwater results are frequently compared to EPA Regional Screening Levels (RSLs; formerly
called preliminary remediation goals [PRGs]) as a first step in determining whether response actions
may be needed to address potential human health exposures. The RSLs are chemical-specific
concentrations that correspond to an excess cancer risk level of 1 x 10"6 (or a Hazard Quotient [HQ] of
36
South Tacoma Channel Superfund Site Five-Year Review
-------
1 for non-carcinogens) developed for standard exposure scenarios (e.g., residential and
commercial/industrial). RSLs are not de facto cleanup standards for a Superfund site, but they can
provide a good indication of whether actions may be needed.
Cis-1,2-DCE. In September 2010, EPA completed a review of the cis-l,2-DCE toxicity literature and
posted on IRIS non-cancer toxicity values which resulted in lower tapwater RSL for cis-l,2-DCE.
EPA's 2010 Toxicological Review for cis-l,2-DCE also established safe levels that include at least a
10-fold margin of safety for health effects other than cancer. Any concentration below the non-cancer
RSL indicates that no adverse health effect from exposure is expected. Concentrations significantly
above the RSL may indicate an increased potential of non-cancer effects. EPA's non-cancer screening
value for cis-1,2 DCE is 28 (ig/L. while the groundwater cleanup level (MCL) is 70 (ig/L. The MTCA
B non-cancer cleanup level of 16 (ig/L (Table 2-5) is less (more stringent) than both the EPA non-
cancer RSL and the cleanup goal. There are no current cancer or non-cancer inhalation toxicity values
available for cis-l,2-DCE.
In summary, the selected groundwater cleanup level of 70 (ig/L for cis-l,2-DCE may no longer be
protective. As discussed previously, the change in the non-cancer EPA RSL and MTCA B non-cancer
standards do not affect protectiveness as long as the implementation of the remedy prevents exposures
above the new MTCA B non-cancer standard of 16 (ig/L.
Trans-1,2-DCE. In September 2010, EPA completed a review of the trans-l,2-DCE toxicity literature
and posted on IRIS revised non-cancer toxicity values which resulted in a lower (more stringent)
tapwater RSL for trans-1,2-DCE. The current non-cancer tapwater RSL for trans-1,2-DCE is 86 (ig/L
which is slightly less than the MCL-based groundwater cleanup level of 100 (ig/L. Any concentration
below the non-cancer RSL indicates that no adverse health effect from exposure is expected.
Concentrations significantly above the RSL may indicate an increased potential of non-cancer effects.
Thus, the existing groundwater cleanup level of 100 (ig/L may no longer be protective. The current
MTCA B non-cancer value for trans-1,2-DCE is 160 (ig/L which is above the cleanup level of 100
(ig/L. No MTCA B cancer value currently exists.
In summary, the selected cleanup standard for trans-1,2-DCE may no longer be protective. The change
in the non-cancer RSL does not affect protectiveness as long as the implementation of the remedy
prevents exposures above the new non-cancer RSL of 86 j^ig/L.
1,1,2,2-PCA. In September 2010, EPA completed a review of the 1,1,2,2-PCA toxicity literature and
posted on IRIS non-cancer toxicity values which resulted in higher tapwater RSL. The current cancer
and non-cancer tapwater RSLs for PCA are 0.066 and 280 (ig/L. The selected cleanup level of 0.2
(ig/L is below the non-cancer RSL and within the 0.066 to 6.6 (ig/L protective excess lifetime cancer
risk range and is thus still protective for both cancer and non-cancer effects.
PCE. EPA also recently reassessed PCE toxicity literature for both cancer and non-cancer effects and
released the toxicological review in February 2012, posted on IRIS. The reassessment determined that
the level at which there is lifetime excess cancer risk in excess of lxl0"6 was less stringent than
previously assumed and the multi-pathway tapwater cancer RSL for PCE was subsequently increased
OU 1, Well 12A
37
-------
from 0.11 to 9.7 |ig/L. The non-cancer RSL was also revised based on adverse neurological effects and
resulted in a multi-pathway tapwater non-cancer risk RSL of 35 (ig/L. The PCE groundwater cleanup
level of 0.8 (ig/L thus remains protective for both cancer and non-cancer effects.
TCE. In September 2011, EPA completed a review of the TCE toxicity literature and posted on IRIS
both cancer and non-cancer toxicity values which resulted in lower RSLs for TCE. The multi-pathway
tapwater screening level for chronic exposure for cancer excess risk level of 1E-6 is 0.44 j^ig/L. EPA
uses an excess cancer risk range between 1E-4 and 1E-6 for assessing potential exposures, which
means a TCE groundwater concentration between 0.44 and 44 (ig/L is within the acceptable excess
cancer risk range. The current groundwater cleanup level for TCE of 2.4 (ig/L is within the revised
protective carcinogenic risk range. However, care must be taken to not assume that the acceptable
cancer risk range is protective at all concentrations for non-cancer effects. EPA's 2011 Toxicological
Review for TCE also developed non-cancer toxicity values. Any concentration below the non-cancer
RSL indicates that no adverse health effect from exposure is expected. Concentrations above the RSL
may indicate an increased potential for adverse non-cancer effects. The non-cancer tapwater screening
level for TCE is 2.6 (ig/L. EPA's 2011 toxicity evaluation of TCE's non-cancer effects include a
subchronic outcome of fetal cardiac malformations that may occur during exposure to the pregnant
mother during a nonspecific 21-day period in the first trimester of pregnancy, according to the IRIS
Toxicological Review for TCE. Accordingly, EPA Region 10 recommends limiting TCE exposures
for adult human females of reproductive age so that the average dose or concentration over any 3-
week period is less than or equal to the TCE RfD or RfC. This exposure would likely be without an
appreciable risk of deleterious non-cancer effects, including non-cancer toxicity effects during
development.
Vinyl chloride. EPA last completed a review of vinyl chloride toxicity literature in 2000; therefore no
toxicity revisions have occurred since the 2009 ROD Amendment #2. The cancer and non-cancer RSL
for vinyl chloride are currently 0.015 and 36 (ig/L, respectively. The selected cleanup level of 0.3 (ig/L
is below the non-cancer RSL and within the 0.015 to 1.5 (ig/L protective excess lifetime cancer risk
range and is thus still protective for both cancer and non-cancer effects.
Expected Progress Toward Meeting RAOs
The remedy is progressing toward meeting the Tier 1 objective of a 90% reduction in mass discharge.
Shallow soil excavation has been completed. ISTR and EAB are in the design stages and are
scheduled to be complete by 2015. The baseline mass discharge measurement has been completed,
which is the basis for determining achievement of Tier 1 objectives.
1.7.3. Question C: Has any other information come to light that could call into
question the protectiveness of the remedy?
Ecological risks have not been evaluated for the project area. However, no significant ecological
impacts due to the contamination are expected because the area around the Site is heavily developed as
a commercial/industrial area and lacks suitable habitat. Furthermore, available data suggest that the
contaminant plume does not currently reach local streams or rivers.
38
South Tacoma Channel Superfund Site Five-Year Review
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1.7.4. Technical Assessment Summary
Construction of the remedial actions described in ROD Amendment #2 is still in progress. Shallow
soil contamination to the east of the Time Oil building has been excavated and transported off-site for
disposal. ISTR and EAB are still in the design phase and are scheduled to be complete by 2015. Well
12A water is treated via air stripping prior to use for drinking water. ICs are in place to prevent
exposure to shallow soil during remedial activities and to prevent ingestion of groundwater.
Standards that have changed since the ROD, ROD Amendments, and explanation of significant
differences (ESD) were signed may affect the protectiveness of the remedy. Changes in toxicity values
for cis-l,2-DCE, trans-1,2-DCE, 1,1,2,2-PCA, PCE, and TCE have occurred in the last five years that
may require future re-evaluation of selected cleanup levels (cis-and trans-1,2-DCE) to ensure
protectiveness is maintained. The changes do not affect the current protectiveness since ICs are in
place to prevent exposure above the new standards.
Exposure pathways described in the ROD have not changed. The vapor intrusion pathway was not
evaluated during development of the ROD. USEPA plans to evaluate vapor intrusion after the
remedial actions are complete.
1.8. Issues
Table 1-9 summarizes the current issues for the Well 12 A project area.
Table 2-9. Issues
Issues
Affects Current
Protectiveness
(Y/N)
Affects Future
Protectiveness
(Y/N)
1. Selected cleanup levels for cis- and trans-l,2-DCE may no longer
be protective following 2011 changes in toxicity values.
N
Y
2. Evaluation of the vapor intrusion pathway is needed.
N
Y
1.9. Recommendations and Follow-up Actions
Table 1-10 provides recommendations to address the current issues at the Well 12A, along with
proposed milestone dates to achieve the follow-up actions.
OU 1, Well 12A
39
-------
Table 2-10. Recommendations and Followup Actions
Issue
Recommendations and
Followup Actions
Party
Responsible
Oversight
Agency
Milestone
Date
Affects
Protectiveness (Y/N)
Current
Future
1
Re-evaluate the groundwater
cleanup level for cis- and trans-1,2-
DCE and adjust if necessary to
maintain future protectiveness after
achievement of Tier 1 criteria.
Ecology/EPA
EPA
09/2018
N
Y
2
Evaluate vapor intrusion pathway
after achievement of Tier 1 criteria.
EPA
EPA
09/2018
N
Y
1.10. Protectiveness Statements
The remedy at Well 12A is currently protective of human health and the environment in the short
term. In the interim, remedial activities completed to date have adequately addressed all exposure
pathways that could result in unacceptable risks in these areas. However in order for the remedy to be
protective in the long term, the remedial actions for the source area should continue to be
implemented.
1.11. Next Review
This is a Site that according to the CERCLA statute, as amended, requires ongoing five-year reviews
as long as contaminants remain on site that do not allow for unlimited use and unrestricted exposure.
The next five-year review will be due within five years of the signature date of this five-year review
(September 2018)
40
South Tacoma Channel Superfund Site Five-Year Review
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[This page is intentionally left blank.]
OU 1, Well 12A
41
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Well 12A Figures
42
South Tacoma Channel Superfund Site Five-Year Review
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[This page is intentionally blank]
OU 1, Well 12A
43
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Highway 16
Former Time
Oil Building-
Washington
Tacome
CDM Well 12A Superfund Site Figure 1-1
Smith Tacoma, Washington Well 12A Site Location Map
Figure 2-1. Site location map showing former Time Oil building and Well 12A.
44
South Tacorna Channel Superfund Site Five-Year Review
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F Well12A RD RA\GIS\PfQiects'A/ettical Profiling Mcmo'Oraft January 2012'Ftq 4-8 3D Strat Units mxd
Legend
Surface Fill
Filter Cake
Qvs Gravel
Qvt Till
Qva Outwash
Qpfc
Qpf
Qpogc
Qpogt
Note: The hill south of the site is modeled as
surface fill, but likely includes a combination
of Qva, Qvt, Qvs, and younger glacial deposits,
as well as surface fill-
Plan View of 3D Visualization
Figure 4-8
3D Visualization of
Stratigraphic Units
Figure 2-2. Representation of stratigraphic units.
CDM . Well 12A Superfund Site
SlTlith Tacoma, Washington
OU 1, Well 12A
45
-------
CDM WELL 12A SUPERFUND SUE
L TACOMA, WASHINGTON _ Figure No. 3
mVnlVn Final Excavation Depths
LEGEND:
APPROX. AREA EXCAVATED
DOWN 1 FT BGS
APPROX. AREA EXCAVATED
DOWN 3 FT BGS
APPROX. AREA EXCAVATED
DOWN 5 FT BGS
AREA EXCAVATED DOWN UP
TO APPROX. 15 FT BGS
NOTES:
1. AREAS SHADED BLUE WD GREEN
WERE SHIPPED TO CWM IN
OREGON.
APPROXIMATE LOCATION OF
REMNANTS OF BURIED STEEL
CONTAINER AND 55—GALLON
DRUM
APPROXIMATE
LOCATION OF
APPROXIMATE
LOCATION
OF TRENCH
BOXES
APPROXIMATE LOCATION
OF BURIED STEEL PIPING
2. AREAS SHADED RED AND YELLOW
WERE TREATED WITH SODIUM
PERSULFATE AND LIME. SAMPLED
AND THEN SHIPPED TO CWM IN
OREGON.
3. ALL SLOPES IN FIGURE ARE
APPROXIMATE.
-APPROXIMATE LOCATION
OF BURIED STEEL PIPING
W/////////x&/////;\
Figure 2-3. 2011/2012 final extent of excavation.
46
South Tacoma Channel Superfund Site Five-Year Review
-------
Former
Time Oil
Building
VES
Building
Performance
Radiator
Addition
Building Removed
February 2004
Extraction Well
Pipeline
Warehouse/
Offices
Enclosure}
A'jlo
Glass
Repair
Shop
SEPA
REGION 10
Figure 1-2
Site Map and GETS Sampling Locations
South Tacoma Channel/Well 12A Site
049-RA-RA-1014
S. Tacoma Channel/Well 12A
GETS
O&M MANUAL
LEGEND
® Extraction Well
r®l Containment Vault and
Extraction Well
Former Time Oil
Property Boundary
GETS Groundwater Extraction and
Treatment System
VES Vapor Extraction System
Extraction Well Pipeline
SP Sampling Port
£W Exlraction Well
Note
Parking Area
: SP-1, SP-2, and SP-3 are located in
tlie same general area. TTiey are labeled
individually for identification in the field.
scam in rtn
Source: ICF KAISER
Modified by URS
Figure 2-4. Groundwater extraction and treatment system (GETS) location map.
OU 1, Well 12A
47
-------
Path: F:\Well12A RD RA\GIS^roiectsWerticaI Profiling Memo\Draft January 2012\F ia 5-1 Proposed Thermal Zone.mxd
— (— —** 3 ~r~
Legend
RDI Borings
O Total COC <5000 ug/kg
• Total COC >5000 ug/kg
(•) GETS Extraction Wells
-0- Groundwater Monitoring Wells Installed in 2004
Modeled Aerial Extent of Soil COCs >5000 ug/kg in Vadose Zone (217 to 249 ft msl)
m ama m
11 J Proposed In Situ Thermal Treatment Area
B428
B400
B430
Note:
The in situ thermal treatment area is based
on the modeled aerial extent of soil
contamination (total contaminants of
concern [COCs] greater than 5000 micrograms
per kilogram [ug/kg]) in the vadose zone and
upper saturated zone beneath and in the
vicinity of the former Time Oil building.
smith
Well 12A Super-fund Site
Taconna, Washington
Figure 5-1
Proposed Thermal Treatment
Figure 2-5. Proposed in-situ thermal remediation (ISTR) treatment area.
48
South Tacorria Channel Superfund Site Five-Year Review
-------
F:Well12A RD RA^GIS\ProiecteWertical Profiling M^mo'l.Draft J anuarv 2012\ri'] 41 SurrimaRf Map Boring ruTini Locs_mxd
0412 -0403
MVVrS
B405
JTmM-d!
" B 400
^ICF-4
"jQ
MW-C
MW-305
f OWC-3M
EW-1 M
(SVE) OWC-2
VP.102.
B408d
0400
TOW-3
'CH2M
OWG
¦¦M
MVV-312
:MW-3li' / '
TOW-4
:^ee Adjacent Mapaowyu
4$$T' ' " '' *¦'
:+vWC±r - ¦_ '
TOVV-5
MWjg,
KRRral
0407
¦MW-313
¦E
MVV-,13 B421
TOW-9 -
TOW-8-
TOW-7
TOW-6
MW-307
l0H2M;2.
0417
EW-3":
IWGG5A
B420!
WC C-5
B424
j
M
VP106
Well 9A'•
i mm
[VP 109,
Legend
Vertical Profile Location
Q 2011 RDI Boring
Q 2010 RDI Boring
-0- Groundwater Monitoring Well
Acronym s:
0 - boring
MW - monitoring well
N- north
RDI - Remedial Design Investigation
VP - vertical profile
LVR.107,
,VPJ08
-------
F:WVell1Zft RD RA\SIS\ProiecB\QREPTfigui-e4 1 ProeoseclDecZ012GWmonitam3Loc.tT«d
' TOW-,10
ICF-3
.MIA£306'
Notes
*= EAB pilot injection and monitoring
well locations have not been surveyed
The locations are approximate.
JS>'C7- 4
MV-S05
r MW-1:
_ owc-3irg
'EW-l*> ¦
;(SVEj OWC-2—
MW-15 f / MW-17
CH2M-4
TOW-3
TQW-4
-T0W-5
MW-10;
MW-3^t^
KRRF-l
>MW£13
MW-12'" ICF-5D'
TQW-9-
TOW-8.
TOW-7.
TOW-6
MW-A.
.6H2M-3
MW-307-
I EAB-3'
MW;302_
El
WCC-1A
'See'Adjacent-Map'
-MW1
(WCD)
'GH2Ml2|
WCC-6
6BWi:
CH2SA.1:
:eBWr4i
feBW-,1-1
IWeil .12A1
CBW-f
CBW-
* CBYJ-5
GBW-9
Legend
Groundwater Monitoring Well
(S> Abandoned/lost Monitoring Well
| ^jTime Oil Building Source A rea/ISTR Treatment Zone
5000 ug/kg COC isopleth
Union of TCE & cis-DCE >300 ug/L above 179 ft nnsl
ZlHigh Concentration Ground water Treatment Zone
I j Union of TCE & cis-DCE >300 ug/L below 179 ft msl
Weil ID Coloring
Well IDs highlighted in yellow are proposed for EAB pilot test baseline monitoring in December 2012.
Well IDs highlighted in green are additional wells proposed for the December 2012 quarterly monitoring event.
Acronyms:
COC - contaminant of concern
cis-DCE - cis-1,2-dichloroethene
EAB - enhanced anaerobic bioremediation
ID - identification
ISTR - in situ thermal remediation
msl - mean sea level
MW- monitoring well
N - north
TCE - trichloroethene
ug/kg - micrograms per kilogram
ug/L - micrograms per liter
smith
Well 12A Superfund Site
Tacoma, Washington
Figure 4-1
Recommended Groundwater Performance Monitoring Event #3 (December 2012) Sample Locations
Figure 2-7. Groundwater monitoring wells including interim performance monitoring (IM) wells and enhanced anaerobic bioremediation (EAB) wells.
50
South Tacoma Channel Superfund Site Five-Year Review
-------
F:M/ell12A RD RA\GIS\Projects\Vertical Profiling Memo'Draft January 2012'Fig 4-16 Cont Mass Zones,mxd
Zones A. B
Viewpoint
,
Legend
Zone A: SW of
Time Oil Building
Shallow Zone,
Above 217 ft ms!
Zone B: SW of
Time Oil Building
Deep Zone,
Below 217 ft msl
Zone C: Below
Time Oil Building
Area Shallow
Zone, Above
217 ft msl
Zone D: Below
Time Oil Building
Area Deep
Zone, Below
217 ft msl
cpn/i Well 12A Superfund Site Figure 4-16
Smith Tacoma, Washington Contaminant Mass Zones and
5000 ng/kg Total COC Isopleths
Figure 2-8. Contaminant mass zones in soil.
OU 1, Well 12A
51
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[This page is intentionally blank.]
52 South Tacoma Channel Superfund Site Five-Year Review
-------
ictsWertical Pr ofil in q MsmoXDraft
iry 33 1 2>.F i g 4-1 0 0 W C on toil re O E TS C om pare. mxd
Legend
Wells Used in Contouring
Poteritiometric Contours (fl msl)
Notes
1) Groundwater levels collected N Ov*em ber 9, 2011
with GETS and the City of Tacoma municipal
supply well field, including Well 12A, not in operation.
?) Grnijnd water nnntnurs Qpnpraterl in Mining VisualiTatinn
Software and sliced at elevation 1 84 ft msl.
VCH2M3J
MW302 1
i ¦
MW10~
MW13.
TOW3 ;
TOWB
TOW9'
MW313
MW314
f™12 m wcc2M*1H,*
/ MW14 j&r 5-wCSB9fi ¦*
EWS J • '
A, MWt1?. !
lcf^ w&
:W2^WCC6 -Vwi
Htm
'(MCC1B,
k E W3 -
» ¦ ¦
[CH2M2
IWCC3M
fe-nivioog
MWJKi;
1(CBW7
*
CBW1
Ebwio
>r',CBW11
' 'fv i ii |
CBWS
CBWfi
CBW9
Legend
Wells Used in Contouring
Patentiometric Contours (ft msl)
Notes
1) Groundwater levels collected November 1 7, 2011
wth GETS and the following City of Tacoma municipal
supply wells in operation:
(a) Well 1B at approxim ately 4.8 MGD since 11 /-16
(b) Well 3A at approxim ately 4.8 M GD since 11/15
(c) Well 1 3A at approxim ately 1.1 M GD since 11/15
/2JI other C ity of Tacoma m unicipal wells were offline.
2) Groundwater contours generated in Mining Visualization
Software and sliced at elevation 184 ft msl.
ft md = feet above mean sea level
MGD = million gallons per day
iMWff
lCH2M3
MW302
MW9
MW10
BiMW13
•TOW3
TOW8
TOW9
MW313.
. MW314
I w
I MW/' ,
» smwcjf
WGC2iWCSB9,
pEW5p4MW3i2
- JVCC1B j*-
WCC5 w
~ ICF5S
'WCC6
ICF5D
"5l
EW2 \
CH7M1*
H2M2i
¦
-------
C MJsers^rum pjm\Desktop >Afch GI S\Wel I 12 A\G I S\Proje c1s\EA.B,,,Ful I Seal e De a gnllnje di on_ Lo cator2 m ad
MW-3
Legend
-0- Existing Groundwater Monitoring Wells
-V- Groundwater Extraction Well
Union of TCE and cis-DCE > 300 ug/Labove Qpf
Union of TCE and cis-DCE > 300 ug/Lbelow Qpf
Tax Parcel Boundaries
Y/A Tacorna ROW Work Areas
TOW-2 1
TOW-3
INJ-2^
KRRF-1
jifr.
WCSB 9
Notes
Source aerial: E SRI, Bing Maps, 2011
.
IPBBSnf- ^cH2M-3 *
TOW-10
f WCC-2
MW1 (WCO)
CH2M-1
CH2M-2
CBW-7
CBW-1
CBW-10
IM-2A
IM-2B
IM-2C
Smith
Well 12ASuperfund Site
Tacorna, Washington
Figure xx
Groundwater Plurne and Monitoring Wells
with Parcel Boundaries
Figure 2-10. High-concentration groundwater plume extent.
54
South Tacorna Channel Superfund Site Five-Year Review
-------
CDM. . Well 12ASuperfund Site m,„ Figure 3-16
Smith Tacoma, WA sp"1 Mass Discharge
Figure 2-11. Baseline mass discharge measurements.
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Appendix 1-A: Well 12 A List of Documents
Reviewed
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58 South Tacoma Channel Superfund Site Five-Year Review
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Well 12 A Documents Reviewed
CDM, 2009. Final Focused Feasibility Study, Well 12A Superfund Site, Tacoma, Washington. April
2, 2009.
CDM, 2010. Institutional Control Plan, Well 12A Superfund Site, Tacoma, Washington. August 6,
2010.
CDM, 2010. Draft Basis of Design Report, Well 12A Superfund Site, Tacoma, Washington. October
8, 2010.
CDM, 201 la. Memorandum re: Addendum to the Draft Basis of Design Report, South Tacoma
Channel Well 12A Superfund Site, Tacoma Washington. February 1, 2011.
CDM, 201 lb. Final Mass Discharge Evaluation Work Plan, Well 12A Superfund Site, Tacoma,
Washington. July 19, 2011.
CDM, 201 lc. Memorandum re: South Tacoma Channel Well 12A Groundwater Extraction and
Treatmnet System (GETS) Inspection. August 22, 2011.
CDM, 201 Id. Memorandum re: Final Selection of EAB Amendments for Bench Scale Treatability
Study, Mileston 4, Well 12A Project. December 20, 2011.
CDMSmith, 2012a. Final Exacavation and Disposal Report, Well 12 Shallow Excavation Remedial
Action, Tacoma, Washington. May 16, 2012.
CDMSmith, 2012b. Post Well Rehabilitation, Groundwater Extraction and Treatment System,
Performance Evaluation and Capture Zone Analysis Work Plan. June 9, 2012.
CDMSmith, 2012c. Final ISTR Pre-Design and Vertical Profiling Report, South Tacoma Channel
Well 12A, Superfund Site, Tacoma, Washington. July 2012.
CDMSmith, 2012d. Technical Memorandum, Final Evaluation of GETS Capture for Mass Discharge.
August 14, 2012.
CDMSmith, 2012e. Memorandum, re: Addendum to the Final Technical Memorandum: Evaluation of
GETS Capture for Mass Discharge Assessment. October 1, 2012.
CDMSmith, 2012f. Enhanced Anaerobic Biodegradation Bench Scale Treatability Study Final Report,
Tacoma, Washington, October 30, 2012.
CDMSmith, 2012g. Final Groundwater Performance Monitoring Report, Event #2 (August 2012),
South Tacoma Channel Well 12A Superfund Site, Tacoma, Washington. December 13, 2012.
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CDMSmith, 2013a. Final Groundwater Performance Monitoring Report, Event #3 (December 2012)
and HydraSleeve™ Evaluation, South Tacoma Channel Well 12A Superfund Site, Tacoma,
Washington. March 18, 2013.
CDMSmith, 2013b. Draft Final Well 12A Mass Discharge Baseline Memorandum. March 29, 2013.
URS and CH2MHill, 2004. Operation and Maintenance Manual Groundwater Extraction and
Treatment System, South Tacoma Channel/Well 12A Superfund Site. December 2004.
USEPA, 1983. EPA Superfund Record of Decision: Commencement Bay, South Tacoma Channel,
EPA ID: WAD980726301, OU 01, Tacoma, Washington. March 18, 1983.
USEPA, 1985. EPA Superfund Record of Decision Amendment: Commencement Bay, South Tacoma
Channel, EPA ID: WAD980726301, OU 01, Tacoma, Washington. May 3, 1985.
USEPA, 2008. Five-Year Review Report, Commencement Bay, South Tacoma Channel Superfund
Sites, Tacoma, Washington. September 2008.
USEPA, 2009. Amendment #2 to the Record of Decision for the Commencement Bay - South
Tacoma Channel Superfund Site, Operable Unit 1, Well 12A, Tacoma, Washington. October 2009.
USEPA, 2010. A Memorandum of Agreement between The United States Environmental Protection
Agency and City of Tacoma, Department of Public Utilities, Water Division (Tacoma Water), Well
12A Operation During Superfund Remedy. December 2010.
USEPA, 2012. Explanation of Significant Differences to the Amended Record of Decision for the
Commencement Bay - South Tacoma Channel Superfund Site, Operable Unit 1, Well 12A, Tacoma,
Washington. June 2012.
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Appendix 1-B: Well 12 A Site Inspection Trip
Report
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Well 12A Site Inspection Trip Report
Attendees
USACE:
Heather Whitney, USACE Seattle District Chemist
Kristen Kerns, USACE Seattle District Physical Scientist
CDM:
Domini Giaudrone, CDMSmith Engineer
City of Tacoma Water:
Dave (no last name provided), TacomaWater representative
Purpose
Well 12A/Time Oil is one operable unit within a USEPA-led CERCLA site in which a five-year
review is being conducted. A site visit was conducted to provide information about the site's status
and to visually inspect and document the conditions of the remedy, the site, and the surrounding area
for inclusion into the fourth Five-Year Review Report.
Report
On 5 March 2013, Heather Whitney and Kristen Kerns drove from the Seattle District office to the
Well 12A/Time Oil Superfund Site located in Tacoma, Washington, arriving at approximately 1300
hrs, the arranged meeting time. The weather was cool and cloudy. The site is located in a
commercial/industrial area west of Interstate 5.
The USACE team met with Mr. Giaudrone at the CDMSmith field office area near the former SVE
facility. Mr. Giaudrone conducted the tour. The tour started with a walk-through inspection of the
former SVE facility. CDMSmith had a plumbing sub-contractor on-site attempting to get the
municipal water running to the facility so that CDMSmith would have a ready supply of clean water
for the upcoming pilot-scale bioremediation testing. After turning on the water to the building, a tank
labeled "waste solvent" (and previously known to be empty) was discovered to be full. CDMSmith
had just finished pumping the suspect water into a drum with samples taken for inspection and
potentially for analysis, although the fluid was thought to be linked to the plumbing work occurring
simultaneously. The SVE components were still in their dormant condition since shut-off in the late
90s. No vandalism was apparent to components inside the facility, although parts of the external
assembly were missing, presumably stolen.
The entire SVE facility is within a fenced area that includes access to the west side of the Time Oil
building. Trailers and random debris were observed scattered around the inside of the fenced area. The
owners of the property and Time Oil building (Western Moving Company) were not present.
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Following inspection of the SVE facility, the team walked through the former Time Oil building,
which contained mounds of furniture and other personal items around the inside perimeter of the main
warehouse. A few boats were also parked inside the building. To the south (within the older brick
portion of the building), evidence of a former apartment renovation was apparent, although the area
was clearly not in current use. One room was piled full of personal belongings.
Dominic, Kristen, and Heather next walked to the adjacent GETS facility. Dominic reported that the
carbon was just changed out on February 26, 2013. The extraction wells were currently in operation
and no problems were observed.
Kristen and Heather next drove to the Well 12A wellhead treatment facility where they were met by
two TacomaWater representatives (Dave & one other person). The team walked around the facility
taking photos. Nothing unusual was noted. The well was not currently in operation.
The site visit concluded at approximately 1430 and the USACE team drove back to the district office.
Photographs:
FIELD OFFICE
3012 S. Fife Street
US ENVIRONMENTAL PROTECTION AGENCY
SOUTH TACOMA CHANNEL WELL I2A
SUPERFUNO PROJECT
3018 SOUTH FIFE STREET TACOMA. WA 98409
IN CASE OF EMERGENCY PLEASE CALL-
(206) 44 4 -4 056
m ™A«C"T THE 0ESC»»,™» ««» NATURE OF
E*£HetNCr AMD fOUH NAME AND TELEPHONE
'• NUMBER TO THE EMERGENCY OPERATOR
Photo 1. View looking northwest into Time Oil property (SVE building in background).
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South Tacoma Channel Superfund Site Five-Year Review
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Photo 2. North end of Fife Street looking west towards former SVE facility
Photo 3. View looking north into Time Oil property from gated entrance
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Photo 4. Close-up of external SVE structures
Photo 5. Former SVE piping along railroad to north of SVE building
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K1 '
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Photo 6. Control room of former SVE facility.
Photo 7. Inactive carbon tanks formerly used for SVE operations.
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Photo 8. Dormant feed tanks for SVE operations.
Photo 8. "Waste solvent"' container that filled with unknown liquid when municipal water was turned
on in the building on March 6, 2013.
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3hoto 9. Small room in SVE facility in which dead rat was removed.
Photo 10. Staging area within former SVE facility for upcoming pilot-scale bioremediation testing
(view looking south).
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Photo 11. Storm water drain and oil-water separator (under concrete cap; unknown condition) next to
SVE facility.
Photo 12. New Time Oil building (left) and old Time Oil building (right).
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5hoto 13. South side of old Time Oil building.
Photo 14. Former east tank farm area, view looking southwest towards Time Oil building
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Photo 15. Interior of new Time Oil building, view looking northeast.
Photo 16. View looking southwest within old Time Oil building.
72 South Tacoma Channel Superfund Site Five-Year Review
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Photo 17. Former East tank farm area as viewed from second story window of old Time Oil building.
Photo 18. Wells to be used in pilot-scale bioremediation testing immediately south of Time Oil
property.
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Photo 19. Extraction well 3 (EW-3) on east side of Fife Street; view looking north.
Photo 20. GETS facility as viewed from south east.
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Photo 21. EW-1 (located adjacent to GETS)
Photo 22. Well 12A wellhead treatment system as viewed from southeast
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Photo 23. Well 12A wellhead treatment facility as viewed from the east
Photo 24. Well 12A Control building and electrical.
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Photo 25. Interior of Well 12A control room
5hoto 26. Blow-out pond used to purge well located direct south of air stripping towers.
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'hoto 27. Close-up of one the blower intake vents for the air stripping towers
Photo 28. North side view of the air stripping towers.]
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Appendix 1-C: Well 12 A Site Inspection
Checklist
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Five-Year Review Site Inspection Checklist
I. SITE INFORMATION
Site name: Well 12A/Time Oil
Date of inspection: 05 March 2013
Location: Tacoma, WA
EPA ID: WAD980726301
Agency, office, or company leading the five-year
Weather/temperature: Cloudy, 45 F
review: EPA Region 10
Remedy Includes: (Check all that apply)
~ Landfill cover/containment
~ Monitored natural attenuation
£3 Access controls
~ Groundwater containment
~Institutional controls
~ Vertical barrier walls
£3 Groundwater pump and treatment
~ Surface water collection and treatment
Other: Well-head treatment (Well 12A),
Groundwater monitoring
Attachments: ~ Inspection team roster attached
~ Site map attached
II. INTERVIEWS (Check all that apply)
1. O&M site manager
Name
Title Date
Interviewed ~ at site ~ at office ~ by phone Phone no.
Problems, suggestions; ~ Report attached
2. O&M staff Dominic Giaudrone
CDM Engineer 5/5/2013
Name
Title Date
Interviewed ~ at site dat office ~ by phone Phone
no
Problems, suggestions; ~ Report attached
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3. Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency response
office, police department, office of public health or environmental health, zoning office, recorder of
deeds, or other city and county offices, etc.) Fill in all that apply.
Agency: Washington State Department of Ecology
Contact: Chris Maurer, Project Manager
Name Title Date Phone no.
Problems; suggestions; ~ Report attached See Appendix 1-D
Agency Tacoma Water_
Contact Chris Johnson, Senior Principal Engineer and Operations supervisor_
Problems; suggestions; ~ Report attached See Appendix 1-D _
Agency Tacoma Water_
Name Title Date Phone no.
Contact Craig Downs
Name Title Date Phone no.
Problems; suggestions; ~ Report attached See Appendix 1-D
4. Other interviews (optional) ~ Report attached.
Leslie Rose, Citizens for a Healthy Bay (See Appendix 1-D).
III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)
1. O&M Documents
~ O&M manual ~ Readily available ~ Up to date £3 N/A
~ As-built drawings ~ Readily available ~ Up to date ^ N/A
~ Maintenance logs ~ Readily available ~ Up to date £3 N/A
Remarks
2. Site-Specific Health and Safety Plan ^ Readily available ~ Up to date ~ N/A
~ Contingency plan/emergency response plan ~ Readily available ~ Up to date ~ N/A
Remarks
3. O&M and OSHA Training Records Readily available ~ Up to date ON/A
Remarks
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4.
Permits and Service Agreements
~ Air discharge permit ~ Readily available ~ Up to date £3 N/A
~ Effluent discharge ~ Readily available CHUp to date ^ N/A
~ Waste disposal, POTW ~ Readily available ~ Up to date £3 N/A
~ Other permits ~ Readily available ~ Up to date Kl N/A
Remarks No discharge permit for treated Well 12A effluent exists. This is an ongoing issue
between City of Tacoma and Ecology.
5.
Gas Generation Records ~ Readily available ~ Up to date ^ N/A
Remarks
6.
Settlement Monument Records ~ Readily available
Remarks
~ Up to date
KIN/A
7.
Groundwater Monitoring Records ^ Readily available
Remarks
~ Up to date
~N/A
8.
Leachate Extraction Records ~ Readily available
Remarks
~ Up to date
N/A
9.
Discharge Compliance Records
~ Air ~ Readily available
~ Water (effluent) ^ Readily available
Remarks
~ Up to date
~ Up to date
N/A
~ N/A
10.
Daily Access/Security Logs ~ Readily available ~ Up to date ^ N/A
Remarks Site is only accessed on an as needed basis by the contractor, CDMSmith for
remedial design activities.
IV. O&M COSTS
1.
O&M Organization
~ State in-house ~ Contractor for State
~ PRP in-house ~ Contractor for PRP
~Federal Facility in-house ~ Contractor for Federal Facility
£3 Other City of Tacoma Water manages the Well 12A wellhead treatment system. Tacoma Water
and Ecology jointly manage the GETS.
2.
O&M Cost Records
£3 Readily available ~ Up to date
~ Funding mechanism/agreement in place
Original O&M cost estimate $100,000 per year (from Chris Maurer interview)
Breakdown attached
Total annual cost by year for review period if available
~
3.
Unanticipated or Unusually High O&M Costs During Review Period
Describe costs and reasons: None described during the site visit.
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V. ACCESS AND INSTITUTIONAL CONTROLS E3 Applicable ~ N/A
A. Fencing
1. Fencing damaged ~ Location shown on site map ~ Gates secured ~ N/A
Remarks. The Time Oil property, GETS, and Well 12A wellhead treatment system are all enclosed in
fencing in good condition.
B. Other Access Restrictions
1. Signs and other security measures ~ Location shown on site map ~ N/A
Remarks Time Oil property clearly labeled with site information and contact information.
C. Institutional Controls (ICs)
1. Implementation and enforcement
Site conditions imply ICs not properly implemented ~ Yes ~ No ^ N/A
Site conditions imply ICs not being fully enforced ~ Yes ~ No N/A
Type of monitoring (e.g., self-reporting, drive by)
Frequency
Responsible party/agency
Contact
Name
Title
Date
Phone no.
Reporting is up-to-date
~ Yes
~ No
~
N/A
Reports are verified by the lead agency
~ Yes
~ No
~
N/A
Specific requirements in deed or decision documents have been met
~ Yes
~ No
~
N/A
Violations have been reported
~ Yes
~ No
~
N/A
Other problems or suggestions: ~ Report attached
ICs are planned, but have not vet been developed or implemented.
2. Adequacy ~ ICs are adequate ^ ICs are inadequate ~ N/A
Remarks: All residents within this area use municipal water. The likelihood of a private owner installing
a drinking water well is small. Vapor intrusion risk into buildings from contaminated soil and
groundwater contamination exists, although since no one currently lives on the property, exposure
likelihood is low. EPA plans to evaluate VI risk after active remediation is complete and institute ICs at
that time if needed.
D. General
1. Vandalism/trespassing ~ Location shown on site map £3 No vandalism evident
Remarks
2. Land use changes on site ~ N/A
Remarks: Land use remains commercial/industrial.
3. Land use changes off site ~ N/A
Remarks: No changes observed.
VI. GENERAL SITE CONDITIONS
A. Roads ~ Applicable ^ N/A
1. Roads damaged ~ Location shown on site map ^ Roads adequate ~ N/A
Remarks
B. Other Site Conditions
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Remarks
VII. LANDFILL COVERS ~ Applicable M N/A
VIII. VERTICAL BARRIER WALLS ~ Applicable |g| N/A
IX. GROUNDWATER/SURFACE WATER REMEDIES ~ Applicable ~ N/A
A. Groundwater Extraction Wells, Pumps, and Pipelines ~ Applicable ~ N/A
1.
Pumps, Wellhead Plumbing, and Electrical
~ Good condition ~ All required wells properly operating ~ Needs Maintenance ~ N/A
Remarks GETS was not operating during site visit.
2.
Extraction System Pipelines, Valves, Valve Boxes, and Other Appurtenances
~ Good condition ~ Needs Maintenance
Remarks
3.
Spare Parts and Equipment
~ Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks
B. Surface Water Collection Structures, Pumps, and Pipelines ~ Applicable ~ N/A
C. Treatment System ~ Applicable ~ N/A
1.
Treatment Train (Check components that apply)
~ Metals removal ~ Oil/water separation ~ Bioremediation
~ Air stripping ~ Carbon adsorbers
~ Filters
~ Additive (e.£., chelation agent, flocculent)
~ Others
£3 Good condition ~ Needs Maintenance
~ Sampling ports properly marked and functional
~ Sampling/maintenance log displayed and up to date
£3 Equipment properly identified
~ Quantity of groundwater treated annually
~ Quantity of surface water treated annually
Remarks Carbon is changed semi-annually.
2.
Electrical Enclosures and Panels (properly rated and functional)
~N/A £3 Good condition ~ Needs Maintenance
Remarks
3.
Tanks, Vaults, Storage Vessels
~N/A £3 Good condition ~ Proper secondary containment ~ Needs Maintenance
Remarks
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4.
Discharge Structure and Appurtenances
~ N/A £3 Good condition ~ Needs Maintenance
Remarks
5.
Treatment Building(s)
~ N/A ~ Good condition (esp. roof and doorways) ~ Needs repair
~ Chemicals and equipment properly stored
Remarks
6.
Monitoring Wells (pump and treatment remedy)
£3 Properly secured/locked ^ Functioning £3 Routinely sampled ^Good condition
£3 All required wells located ~ Needs Maintenance ~ N/A
Remarks
D. Monitoring Data
1.
Monitoring Data
£3 Is routinely submitted on time ~ Is of acceptable quality
2.
Monitoring data suggests:
~ Groundwater plume is effectively contained ~ Contaminant concentrations are declining
D. Monitored Natural Attenuation
1.
Monitoring Wells (natural attenuation remedy)
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~All required wells located DNeeds Maintenance ^N/A
Remarks
X.
OTHER REMEDIES
If there are remedies applied at the site which are not covered above, attach an inspection sheet describing
the physical nature and condition of any facility associated with the remedy. An example would be soil
vapor extraction.
XI. OVERALL OBSERVATIONS
A.
Implementation of the Remedy
Describe issues and observations relating to whether the remedy is effective and functioning as designed.
Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume,
minimize infiltration and gas emission, etc.).
See Section 1.7.1
B.
Adequacy of O&M
Describe issues and observations related to the implementation and scope of O&M procedures. In
particular, discuss their relationship to the current and long-term protectiveness of the remedy.
_See Section
1.7.1.
C.
Early Indicators of Potential Remedy Problems
Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high
frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be
compromised in the future.
_See Section
1.7.1
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D. Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
See Section 1.7.1
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Appendix 1-D: Well 12 A Interview Transcripts
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Well 12 A Interview Transcripts
Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Date:
Well 12A, South Tacoma Channel Superfund Site
WAD980726301
Christopher Johnson, Tacoma Water, Supply Operations Supply
15 February 2013
Interview Method:
Interviewers:
Phone Interview
Heather Whitney, Sharon Gelinas
Q: What is your current role as it relates to the site? How long have you been aware of or associated
with the site?
Senior principal engineer. Operations supervisor. Decides when to turn the production wells on/off.
Well 12A is on an every other year schedule. Only use it for peak season (summer). It was just used
last summer (2012) as part of pumping test at Well 12A. It is on schedule for this year. We use the
wells at least as much to make sure the well is maintained and in good shape.
Testing involves just discharging. This well was installed to intercept and treat the plume. The well
system would otherwise be able to pull the plume towards the main well field. 12A will kick on to
protect the other wells. Treated water will go into production line.
Tacoma is building a new groundwater treatment system in the future.
Q: What is your overall impression of the work conducted at the site to date?
The consultant (CDMSmith) was pretty good to work with. They were fairly thorough and
understandable of TacomaWater's needs. Things just get delayed because of the testing. I'm not part
of the cleanup piece. They were good to work with. I could tell them what I was thinking and they
were responsive.
Q: Have there been routine communications or activities (site visits, inspections, reporting activities,
etc.) conducted by your office regarding the site? (If so, please give purpose and results.)
Communications with CDMSmith were as needed. They [CDMSmith] would contact TacomaWater to
keep TacomaWater informed. [They] Gave TacomaWater enough lead time.
Q: Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
We have a contract with Ecology to provide operation and maintenance for the GETS. Talk to Craig
Downs. He will clarify that relationship.
Well 12A - we have an intrusion alarm on the pump house. Send mechanic out on weekly basis to
check all of the well sites to check for damage, tampering, etc. At least every other testing of Well 12a.
We have 24-hour water control center.
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Q: Would you say that O&M and/or sampling efforts have been optimized? Are there portions of the
remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
Talk to Craig. Last year we updated the electrical panels that support the blowers at Well 12A. We feel
like everything is pretty much upgraded. May be some operational changes to save on power.
Q: What is the current status of construction? Have any problems or difficulties been encountered that
have impacted construction progress or implementability?
It's certainly not convenient to run wells and knowing which wells to run. We would like to
decommission Well 12A if possible.
We have had all the blowers kick on, and we think we may be able to run some, not all to minimize
using all at once to save on electrical.
Q: What is the status of the extraction wells in the GETS?
Status of wellhead treatment/air strippers?
Are there any other significant construction activities proposed?
What does the monitoring data show?
Talk to Craig.
Q: Have there been unexpected O&M difficulties or costs at the site in the last five years? If so, please
give details.
Had to upgrade electrical service at Well 12A. Weather had rotted away wood wall on which electrical
controls were mounted. May need painting in future. Upgraded the communication system as well so
we can control remotely. Upgrades happened 2012, maybe 2011.
Q: Are you aware of any institutional controls, site access controls, new ordinances in place, changes
in actual or projected land use, complaints being filed or unusual activities at the site? If so, please
describe in detail.
No. Tacoma Pierce County Health Dept has ordinance to prevent people from discharging water. Our
concern is that this is our primary aquifer.
Q: Are private wells allowed?
I don't know what the regs are. State or County Health Dept may know the answer. We have to
exercise our water right every now and then, and must report on that annually to state dept of Health.
Q: Are you aware of any ongoing community concerns regarding the site or its administration?
No.
Q: Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
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No.
Q: Have any problems been encountered which required, or will require changes to this remedial
design or ROD?
No, not that I am aware of. I thought if we run the wells too long through the blow-off, we risk
overtopping the blow-off. It hasn't happened or happened a while ago in the past. The blow-off is a pit
next to the well. After blow-off, the water will go to the production line. We usually only blow-off for
2-3 minutes, but sometimes, because of the testing we blow-off longer.
Q: Do you have any comments, suggestions, or recommendations regarding the site's management,
operation, or any other aspects of the site?
No. It would just be nice to get it done and have it taken of. Talk to Craig.
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Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Date:
Well 12A, South Tacoma Channel Superfund Site
WAD980726301
Craig Downs, Tacoma Water
20 February 2013
Interview Method:
Interviewers:
Phone Interview Follow-up Call
Heather Whitney
Notes from follow-up call with Craig Downs on 2/20/2013.
Q: Who owns the GETS?
I think EPA officially owns the GETS. Water is pumped through carbon filters. Discharge to
stormwater system. EPA also built a SVE system which they ran for a few years and then shut down.
In 2005, EPA went to Ecology to hand off GETS. Ecology took on O&M of GETS system in 2005.
Prior to that, EPA had a contractor running the GETS. Ecology hired TacomaWater to do the actual
O&M and keep the system running. TacomaWater takes the samples and submits the info to Ecology.
Ecology has a vendor that does the carbon change-out.
Generally, the GETS runs continuously. CDMSmith is EPA's consultant. There's been times when
CDMSmith wants GETS shut down for their remediation studies.
Well 12A is confusing because it is not near the Time Oil building. Well 12A has the air stripping
towers.
History. Contamination found in 80s. Air stripping treatment system built in 80s. Way over-built.
Sized to treat up to 1000 ppm. We are in the low teens, at best. There are five towers. Well puts out
about 3500 gals/min. Flow is split between five towers. We don't throttle Well 12A pumping. In
2008/2009, Tacoma Water tested using fewer towers. Four towers was fine. Three was on the verge of
overflowing piping system. Now we run the flow through 3 towers only. Other 2 towers are still there.
This reduction in tower usage was a big cost savings. Each tower has a blower, we're now using only
60% of the blower power that we used to.
Well 12A is our most expensive well because of the treatment system. We run 12A to protect other
wells (6 and 11) by creating a hydraulic barrier. In 2005, we completed another pipeline from our river
supply (Green River), so now we use the production wells much less frequently since 2005. Some
years we may run 12A for only a few days/year. We now run our wells once every other year to check
their operation.
When you don't run Well 12A much, the contaminant levels drop to below MCLs. Must run the well
to pull the contaminants toward Well 12A.
GETS wells - we physically collect the samples and samples go to EPA's Manchester lab for analysis.
We get the data, but Chris Maurer (Ecology) is the coordinator. There are two carbon filters in series.
Chris looks for breakthrough to determine when to change out carbon.
94
South Tacoma Channel Superfund Site Five-Year Review
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Extraction wells 1 and 2 recently rehabilitated. Well 1 about 80 gal/min. Well 2 about 20 gal/min.
Well 3 is about 12.5 gal/min. Well 4 has been out of service now. EW-5 about 8 gal/min. Total about
120 gal/min for GETS overall. Before rehab, EW-1 was about 40 gal/min; EW-2 about 10 gal/min.
Roughly doubled flow rates.
GETS discharge. We discharge to City of Tacoma stormwater system. Ecology pays a discharge fee to
Tacoma.
Since 2005, demand for production wells has dropped, but we anticipate someday needing full
production well capacity.
Tacoma would like to get Time Oil site cleaned up well enough to be able to run Well 12A without
treatment system.
OU 1, Well 12A
95
-------
Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Well 12A, South Tacoma Channel Superfund Site
WAD980726301
Chris Maurer, Project Manager, Washington State Department of Ecology,
(360)407-7223.
Date:
Interview Method:
Interviewer:
20 February 2013
Telephone
Heather Whitney
Q: What is your current role as it relates to the site? How long have you been aware of or associated
with the site?
I am the project manager for the Site for Ecology for 25 years. Michael Kuntz is a hydrogeologist.
Q: What is your overall impression of the work conducted at the site to date?
I'm pleased with what we've done so far and what were planning to do over the next couple of years.
Q: Have there been routine communications or activities (site visits, inspections, reporting activities,
etc.) conducted by your office regarding the site? (If so, please give purpose and results.)
Yes, I participate in the current weekly telephone calls. I normally visit the site about 2x/year when
they are changing the carbon. Frequency of change-out was originally determined by looking for
breakthrough. Ecology took over system in 2006. Now keeps discharge under 10 ppb for vinyl
chloride using 2 change-outs per year. I get bi-weekly and quarterly monitoring data from the
extraction wells. Tx system is sampled every 2 weeks. In addition, every 3 months the five extraction
wells are sampled (now 4). EPA decided to shutdown EW-4 because it is in a location that will
interfere with the planned ITR.
Ecology has a memo with City of Tacoma whereby the City will maintain the treatment sytem and do
the monitoring. Tacoma's costs are paid by Ecology. Ecology pays about $100,000 a year for GETS
operation plus 2x changeouts (at 40,000 per changeout) plus 20,000 in sampling costs. Sampling
results sent to Tacoma, Ecology, CDMSmith.
Discharge goes into Denali Valley sewer and then into Commencement Bay.
Q: Is there a Discharge permit?
I believe EPA had been paying the city a fee. Ecology declined to pay the fee since taking over the
GETS. The matter has remained in stasis since. This does not cause problems at the day-to-day level.
Problem will eventually need to be resolved by upper division management..
Q: Is there a continuous on-site O&M presence?
No. The site is self-operating, monitored electronically, and capable of remotely contacting a human if
a problem is detected.
96
South Tacoma Channel Superfund Site Five-Year Review
-------
Q: If there is no continuous on-site presence, describe staff and frequency of site inspections and
activities (e.g. what types of monitoring activities occur at what frequencies).
Inspections of the GETS treatment system occurs bi-weekly by the City.
Q: Would you say that O&M and/or sampling efforts have been optimized? Are there portions of the
remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
Yes. The extraction pumps and associated piping in the various extraction wells have either clogged or
failed numerous times in the past. Each time the pump is pulled and a replacement installed.
EW1 and 2 were rehabilitated in 2012.1 think they treated the well with chemicals to remove
biofouling of slots on the well. Biofouling of slots on the well screens has been an ongoing problem.
Q: What is the current status of construction? Have any problems or difficulties been encountered that
have impacted construction progress or implementability?
The ITR is in the planning stages, and I believe a RFP has been issued. EAB is still in planning
phases. Excavation of UST is complete. GETS continues operation.
Q: Do you know about the drums on the property? A: Yes, apparently there were a series of drums
stored next to the SVE building. I believe they contained soil and water from previous exploratory
operations. My understanding is that CDM removed the drums off the site and disposed of them.
CDMSmith on behalf of EPA arranged for the removal of the drums.
Q: What is the status of the two points of compliance, CW-1 and CW-2?
I don't think the locations of the compliance wells have been definitely selected. They were proposed
as part of the remediation.
Q: Status of soil excavation?
Soil excavation as far as current remediation is complete. Former East tank farm area had a UST. UST
and contaminated soil was removed. Excavation backfilled and covered with asphalt. Around the early
1980s, there were two tank farms. One (the west tank farm) where the SVE is. The other was the east
tank farm to the east of the Time Oil building. The tank farms were used by Time Oil.
Q: Are there any trends in the GETS, compliance wells CW-1 and CW-2, or other wells that show
contaminant levels are increasing or decreasing?
Because of all of the recent site work, the monitoring data has been erratic. Prior to the excavation, the
GETS wells showed a general steady decrease for some contaminants. Others have shown little or no
decrease.
Q: Have any new or emerging COCs been identified in Well 12A or nearby wells?
OU 1, Well 12A
97
-------
No. Most of the contaminants found are the ones known to be there all along. One surprise during the
excavation, soil on the east tank farm was found to have naphthalene. Concentrations of naphthalene
were high enough that soil could not be taken off-site for disposal.
Q: Do you think they got it all? A: Yes.
Have there been unexpected O&M difficulties or costs at the site in the last five years? If so, please
give details.
Q: Are you aware of any institutional controls, site access controls, new ordinances in place, changes
in actual or projected land use, complaints being filed or unusual activities at the site? If so, please
describe in detail.
No changes in land use. ICs have not yet been installed. Site has been fenced for many years from
general public visiting. No unusual activities at the site.
The GETS Treatment system was not installed on Time Oil property. The Tx system land is leased
from the local landowner who owns land adjacent to the Time Oil property. State pays cost of annual
lease.
Q: Are you aware of any ongoing community concerns regarding the site or its administration?
No. Because it is an industrial area, the site draws very little attention.
Q: Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
Have any problems been encountered which required, or will require changes to this remedial design
or ROD?
No, not really. The site is very complex as revealed by site investigations. The current planned
treatments have been adjusted accordingly.
Q: Do you have any comments, suggestions, or recommendations regarding the site's management,
operation, or any other aspects of the site?
The state is pleased that compared with the previous Five Year Review that so much more has been
accomplished. The success is due to the aggressive cleanup pursuit by EPA and the State.
Look at the 1998, 2003, and 2008 FYRs and you can see significant progress.
98
South Tacoma Channel Superfund Site Five-Year Review
-------
Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Date:
Interview Method:
Well 12A, South Tacoma Channel Superfund Site
WAD980726301
Leslie Ann Rose, Citizens for a Healthy Bay (CHB)
22 February 2013
Telephone
Interview Contacts: Heather Whitney
Interview Questions
Q: What is your current role as it relates to the site? How long have you been aware of or associated
with the site?
Our relationship/activities are similar to the ones we do with Commencement Bay. We [CHB] provide
community oversight, input community perspective into the process from start.
Q: Do you have funding to provide community oversight to help with this project?
No. We are the only organization in Tacoma that is monitoring both superfund and MTCA cleanups.
We don't get technical assistance funds, but we've just been doing it as part of our work.
We have members and supporters, but beyond that, there is no one homogenous community support
CHB. At the end of the day, there are things on which we differ, but there is consensus about the
endpoint. We work as collaboratively and cooperatively as possible with all stakeholders. Info is
disseminated through quarterly newsletter, annual state of the bay report, always giving presentations
to community groups, and other orgs. We may or may not agree with PRPs. We do not accept cash or
in-kind contributions from active PRPs.
I am the senior policy analyst. I am the technical assistant to a volunteer group of 7 professionals who
act as CHB's technical advisory group. They are multi-disciplinary. All are working professionals.
None work for entities that would pose a conflict of interest. I work with the tech advisors. Everything
that comes out of here is based on best available science. I am the "leader of the pack of volunteers."
CHB has a staff of 6. Founded in 1990. Our founding members were actually members of the citizens
advisory group to EPA for Commencement Bay superfund project. At the end of that process, the
members decided to continue the viewpoints in an organized fashion as CHB. We started working
initially on just the Superfund. Over the years we have expanded our focus and mission. We've really
expanded to cleanup, restore, protect the surrounding waters and watershed. I have one program (toxic
cleanups, land use, critical areas) within CHB.
We try and avoid polarity on projects. We do not receive funding from Well 12A project to provide
citizen/community input. We are concerned because I haven't had time to research the goings-on at
Well 12A as much as we would like.
Q: What is your overall impression of the work conducted at the site to date?
OU 1, Well 12A
99
-------
Communication on this site has been abysmal. I can't even tell you who the project manager is. The
last update that we received was more than 3 years ago right after the reopening of the site work.
We've heard nothing since. This is a sore point. I assume EPA is still actively engaged. But I can't
even verify that. We have real concerns about what is going on, what is being done, and why there is
no communication or outreach or anything.
Well 12A is a municipal well. Right now it is offline. But sooner or later, Tacoma may need that
water, and then what do we do. Contamination headed to nearby wells. But we don't know. We
haven't heard anything in 4 years.
Q: Have there been routine communications or activities (site visits, inspections, reporting activities,
etc.) conducted by your office regarding the site? (If so, please give purpose and results.)
We know nothing. The last communication that I got was the proposed plan. I think it was about 3-4
years ago. Shortly thereafter, Kira Lynch was re-assigned and was no longer the project manager. I
suspect Howard is the new project manager, but until your communication, there was no
communication.
Q: What level of communication would work for CHB?
A: Somewhere in between weekly calls and what we have now since we don't have funding to stay
involved in Well 12A and we have other projects. We would like regular updates as to what the
challenges are, what the solutions are, what is being looked at, what the workplan is, basically, project
status, if there are opportunities or places to include public review and input. Something, anything!
I think Howard and I can work out the details ourselves of an appropriate level of communications.
City of Tacoma and TacomaWater are independent entities that do their own things but coordinate
activities. TacomaWater is a part of Tacoma Public Utilities. We (Tacoma) do things our own way. To
the best of my understanding, Well 12A is being handled strictly by the TacomaWater folks. They are
not required to report to one another.
Q: Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
[Skipped]
Q: Would you say that O&M and/or sampling efforts have been optimized? Are there portions of the
remedy that show wear or may need additional focus during O&M? Please describe how improved
efficiency has or has not occurred.
[Skipped]
Q: What is the current status of construction? Have any problems or difficulties been encountered that
have impacted construction progress or implementability?
[Skipped]
Q: What does the monitoring data show?
100
South Tacoma Channel Superfund Site Five-Year Review
-------
[Skipped]
Q: Have there been unexpected O&M difficulties or costs at the site in the last five years? If so, please
give details.
[Skipped]
Q: Are you aware of any institutional controls, site access controls, new ordinances in place, changes
in actual or projected land use, complaints being filed or unusual activities at the site? If so, please
describe in detail.
[Skipped]
Q: Are you aware of any ongoing community concerns regarding the site or its administration?
[Skipped]
Q: Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
[Skipped]
Q: Have any problems been encountered which required, or will require changes to this remedial
design or ROD?
[Skipped]
Q: Do you have any comments, suggestions, or recommendations regarding the site's management,
operation, or any other aspects of the site?
While Well 12A is not needed right now, a few years of drought could flip the situation and require
expanded use of the production wells.
OU 1, Well 12A
101
-------
[This page is intentionally blank.]
102 South Tacoma Channel Superfund Site Five-Year Review
-------
Appendix 1-E: Well 12 Data Summary
OU 1, Well 12A
103
-------
[This page is intentionally blank]
104 South Tacoma Channel Superfund Site Five-Year Review
-------
Well 12 A Data Summary
Woll1?A GioumiwBiei Dam Summary, 7008-7012
cis-1.2-
trans-1,2-
1,1.2,2-
Tetrachloroethylene
Trichloroethylejie
Dichloroethylene
Dlchloro&thylene
Vinyl Chloride
Tetrachloroethane
Depth
Depth
(ug/L)
(ua/U
(UU/L)
(Ufl/L)
(uo/L)
(uc
l/L)
location
Top
Bcflom
Samples
Min
Max
Min
Max
Min
Max
Min
Max
Min I Max
Min
Max
Cleanup Level
0.8
2.4
70
100
0.3
70
CBW-1
44 9
54.9
1
1 U
1 U
1.8
1.8
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
CBW-10
149
169
3
0,22 UJ
1 u
7.2 J
21
0.23 J
1 U
0.71 J
2.4 J
0.08 UJ
1 U
0.54 J
2 U
CBW-11
144 9
1589
1
1 U
1 u
8.5
8,5
1 U
1 u
0.83 J
0 83 J
1 U
1 U
1 U
1 U
CBW-4
1S7
187
1
1 U
1 u
S.3
8.9
1 U
1 u
0 82 J
0.82 J
1 U
1 U
1 u
1 U
CBW-5
178 2
188.2
1
1 U
1 u
3
3
7.2
7,2
1 U
1 U
1 U
1 U
1 u
1 U
CBUV-S
138
158
1
1 u
1 u
1 U
t U
1 u
1 u
1 U
1 U
1 u
1 U
1 u
1 U
CBW-7
79
99
3
0.08 UJ
1 u
13 J
27
0.24 J
2 U
0.77 J
2.4
0.08 UJ
1 u
0.08 UJ
2 U
CBW-9
141 5
161 5
1
1 U
1 u
18
1 8
1 U
1 U
1 U
1 U
1 U
1 u
1 u
1 U
CH2M-1
52
72
3
36
120 J
1100
3100
210
1200
150
760
4.7
160
190 J
320
CH2M-2
160
180
3
0.00 u
1 u
15
21
1,2
1,5
015 J
1 U
0.08 U
1 u
0.08 U
2 U
CH2M-3
55
75
1
1 u
1 u
4.6
4.6
1 U
1 U
1 U
1 U
1 u
1 u
1 U
1 U
CH2M-4
55
75
1
17 J
17 J
52
52
1 U
1 U
1 U
1 U
1 u
1 u
1 U
1 u
0-1
1
50 U
sou
50 U
SOU
SOU
SOU
SOU
50 U
sou
sou
SOU
SOU
EAB-1
47
57
1
410 J
410 J
7900
7900
2500
2500
760 J
760 J
130 U
130 U
33000
33000
EAB-2
47
57
2
98 J
160 J
2000
400(1
390
680
170
290
17 U
25 U
3800
6800
EAB-3
ao
90
2
8.6 J
10 J
130
150
300
390
200
200
100
180
57
60
EAfr4
80
90
2
9.5 J
9.6 J
140
150
360
400
220
240
130
180
59
63
EW-1
60.7
60.8
10
1,2 J
2 U
50
73
24
35
14
18
0.95 J
2.7
3 2
3.9 J
EW-2
50.2
737
10
9.1 J
14
180
250
41
75
26
43
1.1 J
5.8
14
27 J
EW-3
46 a
703
10
4.3 J
69
230 J
1000
180 J
340
84 J
150
10 J
21
87
2500
EW-4
46.6
69,5
1
2.9
2.9
100
100
2200
2200
1400
1400
270
270
150
150
EW-5
47.6
71 1
11
2.9 J
7.5 U
51 J
75
1300 J
2200
730
1400
170 J
330
29
330
ICF-2
61
71
3
1.2 J
3,8 J
310 J
1300
310 J
1100
76
350
2.4 J
53
1 6
6.7 U
ICF-3
265
36.5
1
2 J
2 J
1.3
1.3
1 U
1 u
1 U
1 U
1 U
1 U
1.3
13
ICF-4
28.5
385
1
SOU
50 U
SOU
50 U
69
69
34 J
34 J
95
95
SOU
SOU
ICF-5D
44.5
54,5
3
13 U
42 J
190
220 J
1400 J
3100
170
610
91
230
7 3 J
81
ICF-5S
31.5
41 5
3
15 J
2d J
180
250 J
38 J
190
79 J
100
0 5 UJ
1.5
9.1 J
22
IM-1A
57 9
62,S
3
0 16 J
0 28 J
9.7
11
2,8
3 4
0 88
1 2
0 08 U
0.08 U
I 5
1 7
IM-1B
70.6
75.6
3
0.46 J
0.63 J
34
70 J
2.7
4.5 J
2
4.2 J
0 16 U
0.24 UJ
1.3
2.3 J
IM-1C
104.7
109,7
3
0.08 UJ
3.9 J
0.08 UJ
9.7
0.73 J
15
0.08 UJ
1,4
0.08 UJ
0.08 UJ
0.08 UJ
2.4
IM-2A
57.3
623
3
2 J
3.3 J
65
130 J
72
97 J
3.9 J
4.9 J
0 5 UJ
0.5 UJ
2 UJ
2 UJ
IM-2B
70.5
75.5
3
0.5 UJ
0.56 J
12 J
13
2 UJ
2 UJ
1.2 J
14 J
0.5 UJ
0 5 UJ
2 UJ
2 UJ
IM-2C
105.2
110 2
3
0 5 UJ
10U
2200
2500 J
?6CI
330 J
630
76OJ
63 J
62 J
2 UJ
40 U
INJ-1
48
63
1
98 J
98 J
2800
2800
1300
1300
430
430
47 J
47 J
12 00
1200
INJ-2
80
90
1
7.2 J
7.2 J
100
100
350
350
200
200
170
170
44
44
KRRF-1
63
73
3
1,3 J
2,1 J
73
150 J
16
36
97
20
0.5 R
1.7
1 6
3.7
MW-301
141
146
1
1 U
1 u
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
MW-302
101
106
4
0 5 U
1 u
/5
44
15
19
46 J
86
5.9 J
21
1 U
2 U
MW-304
1405
150 5
1
1 U
I u
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 u
1 U
MW-305
101
106
1
1 u
1 u
1 U
1 U
2,1
2,1
1 U
1 U
2.6
2.6
1 u
1 U
MW-306
139
149
1
1 u
1 u
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 u
1 U
MW-307
145
155
1
1 u
1 u
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 u
1 U
MW-308
146
156
1
1 u
1 u
15
15
6
6
1,7
1.7
0.81 J
0,81 J
1 u
1 U
MW-309
104
109
2
0 5 U
0.8 UJ
64 J
77
2,3 J
2.8 J
55 J
6
0.5 U
0 8 UJ
0.8 UJ
2 U
MW-310
70
75
2
0,5 U
0,57
21
23
0.71
0.99 J
2.2
2.5 J
0.08 U
0.5 U
1.1
2 U
OU 1, Well 12A
105
-------
Weill 2A Groundwater Data Summary, 2008-2012
cis-1,2-
trans-1,2-
1,1,2.2-
Tetrachloroethylene
Tnchloroethy lene
Dtchloroethylene
Dich loroethyl ene
Vinyl Chloride
Tetrachl oroeth an e
Depth
Depth
#
(ug/L)
(ug/L)
(ug/L)
! (U£
I/O
(ug/L)
(lie
l/L)
Location
Top
Bottom
Samples
Mln
Max
M in
Max
Mln
Max
Min
Max
Min
Max
Min
Max
Cleanup Level
0.8
2.4
70
100
0.3
70
MW-311
102
107
2
0.08 UJ
0.5 U
0 08 UJ
0 5 U
0.08 UJ
2 U
0.08 UJ
0.5 U
0.08 UJ
0.5 U
0.08 UJ
2 U
MW-312
68
73
2
0.08 UJ
0,5 U
20
23 J
3.2 J
3,9 J
0.58 J
0.73 J
0.08 UJ
0.5 U
0.08 UJ
2 U
MW-313
67,5
72.5
2
2.4 J
4.2 J
100
320 J
77
140 J
64
95 J
10 J
25
39
340 J
MW-314
325
47.5
2
59 J
67
540
550 J
510
900 J
130
160 J
2.5 U
26 J
430
660 J
MW-89.7
50.79
60.79
1
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
MW-A
48
68
1
1 U
1 U
3.8
3.8
1 U
1 U
1 U
1 u
1 u
1 U
1 U
1 u
MW-B
41
61
1
1 u
1 U
15
15
1.2
1.2
0.98 J
0.98 J
1 u
1 U
1 u
1 U
MW-C
33
53
3.4 J
O J
71 J
260
3.8 J
89
2 J
82
0.5 R
8.6
7 J
38
SP-1
2.7 J
11
100 J
190
120
150
69
87
9.7
17
19 J
250
TOW-1.0
55
85
1
1 U
1 U
2.3
2.3
1 U
1 U
1 U
1 u
1 U
1 U
1 U
1 U
TQW-4
55
85
1.6 J
3.2 J
50 J
130
280
760 J
250
450 J
140
710 J
3.4 J
81
7WT-10
164.5
0
1
1 U
1 U
1 U
1 u
1 U
1 U
1 U
1 u
1 U
1 U
1 U
1 U
VP101
43
43
1
8.5
8.5
250
250
48
48
27
27
0.5 U
0.5 U
38
38
VP101
48
48
1
13
13
380
380
80
80
44
44
1 u
1 U
69
69
VP101
57
57
1
40
40
700
780
930
930
290
290
350
350
96
96
VP101
69
69
1
1.7 J
1.7 J
41
41
23
23
11
11
6.6
6.6
2 U
2 U
VP101
79
79
1
1.8 J
1.8 J
55
55
5.3
5.3
7.8
7,8
0,5 U
0 5 U
2 U
2 U
VP101
88
88
1
2.5 J
2.5 J
120
120
9.9
9.9
20
20
0.5 U
0.5 U
5/3
5.3
VP101
100
100
1
25 U
2.5 U
540
540
250
250
530
530
34
34
10 U
10 u
VP 102
40
40
1
5.4
5.4
21
21
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP102
50
50
1
1.9 J
1.9 J
21
21
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP102
60
60
1
0.5 U
0.5 U
18
18
1.9 J
1.9 J
1 J
1 J
0.5 U
0.5 U
2 U
2 U
VP102
70
70
1
0.5 U
0.5 U
0.81 J
0.81 J
2.9 J
2,9 J
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP102
80
80
1
0.5 U
0.5 U
13
13
5.8
5.8
6.9
6.9
2 J
2 J
2 U
2 U
VP 102
90
90
1
0.5 U
0.5 U
18
18
6 1
6.1
7.3
7.3
1.9 J
1.9 J
2 U
2 U
VP 102
98.5
98.5
1
0 5 U
0.5 U
8.9
8.9
8.3
8.3
29 J
2.9 J
3 J
3 J
2 U
2 U
VP103
46
46
1
0.76 J
0.76 J
150
150
40
40
20
20
0.63 U
0.63 U
15
15
VP 103
60
GO
1
3,6 J
3.6 J
64
54
19
19
10
10
0.5 U
0.5 U
4 7 J
4.7 J
VP103
70
70
1
1.8 J
1.8 J
68
68
15
15
12
12
0.5 U
0.5 U
2 U
2 U
VP 103
80
80
1
0,5 U
0.5 U
86
86
19
19
15
15
0.5 U
0,5 U
2 U
2 U
VP1Q3
90
90
1
0.84 U
0.84 U
210
210
46
46
50
50
0.84 U
0.84 U
3.3 U
33 U
VP103
110
110
1
0.5 U
0.5 U
70
70
57
57
81
51
35
35
2 U
2 U
VP104
40
45
1
0.5 U
0.5 U
8,1
8.1
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP104
55
60
1
7.4 J
7.4 J
380
380
160
160
100
100
1.6 U
1.6 U
6.3 U
63 U
VP104
70
75
1
0.84 J
0.84 J
33
33
7,9
7.9
5.5
5.5
0,5 U
0.5 U
2 U
2 U
VP104
85
90
1
0.96 J
0.96 J
140
140
15
15
17
17
0.5 U
0.5 U
2.4 J
2.4 J
VP104
103
108
1
1 U
1 U
190
190
73
73
35
35
7.1 J
7.1 J
4 U
4 U
VP105
35
40
1
4.4 J
4.4 J
42
42
2.8 J
2.8 J
1.3 J
1.3 J
0.5 U
0.5 U
2 U
2 U
VP 105
50
55
1
24 J
2.4 J
73
73
19
19
2-1 J
Z1 J
26
26
2 U
2 U
VP 105
65
70
1
0.63 U
0.63 U
150
150
47
47
28
28
47
47
2.5 U
2.5 U
VP105
85
90
1
0.5 U
0.5 U
48
48
35
35
8.7
8.7
20
20
2 U
2 U
VP 105
105
110
1
0.5 U
0.5 U
0,5 U
0.5 U
2 U
2 U
0.5 U
0 5 U
0.5 U
0.5 U
2 U
2 U
VP 106
35
40
1
5.5
5.5
100
100
24
24
12
12
0.5 U
0.5 U
16
16
VP106
50
55
1
0.5 U
0.5 U
31
31
12
12
4.5 J
4.5 J
0.5 U
0.5 U
2 U
2 U
VP106
65
70
1
0.5 U
0.5 U
57
57
11
11
6.2
6.2
0.5 U
0.5 U
2 U
2 U
106
South Tacoma Channel Superfund Site Five-Year Review
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WelUZA Groundwater Data Summary, 2008-2012
cis-1,2-
trans-1,2-
1,1,2.2-
Tetrsch I oroethylen e
Trichloroethylene
Dichloroethylene
Diciiloroethylene
Vinyl Chloride
Tetrachtoroethane
Depth
Depth
#
[UC
/I)
(ug/L)
(uc
ifl.)
tuc
l/L)
(ug/L)
(UC
l/L)
Location
Top
Bottom
Samples
Min
Max
Min
Max
Miti
Max
Min
Max
Min
Max
Min
Max
Cleanup Level
o.a
2.4
70
100
0.3
70
VP 106
85
90
1
0,72 J
0.72 J
86
86
12
12
17
17
1.2 J
1.2 J
2 U
2 U
VP 106
110
115
1
0,5 U
0.5 U
1.4 J
1,4 J
0.35 J
0.95 J
0.5 U
0,5 U
28
28
2 U
2 U
VP 107
35
40
1
1.2 J
1.2 J
33
33
2 U
2 U
0.89 J
0.89 J
0.5 U
0.5 U
2 U
2 U
VP 107
50
55
1
16 J
16 J
360 J
360 J
62 J
62 J
40 J
40 J
10 J
10 J
31 J
31 J
VP 107
65
70
1
1.6 J
1.6 J
36
36
6.5
6.5
5.3
5.3
1 J
1 J
2.2 J
2.2 J
VP 107
85
90
1
4.8 J
4.8 J
480
480
34
34
91
91
2.5 U
2 5 U
5.9 J
5.9 J
VP 107
105
110
1
2.5 U
2.5 U
2100
2100
400
400
uoo
1100
130
130
10 U
10 U
VP108
40
40
1
0.5 U
0.5 U
0.5 U
0 5 U
2 U
2 U
0.5 U
0.5 U
0.5 II
0.5 U
2 U
2 U
VP1O0
55
55
1
3.7 J
3.7 J
150
(50
22
22
21
21
0.63 U
0 63 U
2.5 U
2.5 U
VP 108
70
70
1
0.5 U
0.5 U
25
25
0.92 J
0 S2 J
2.4 J
2.4 J
0.5 U
0.5 U
2 U
2 U
VP 108
90
90
1
2.5 U
2.5 U
490
490
44
44
36
36
2.5 U
2.5 U
10U
10 U
VP108
115
115
1
0.5 U
0.5 U
3.1 J
3.1 J
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP 109
35
40
1
3.6 J
3.6 J
120 J
120 J
4.1 J
4.1 J
4.3 J
4.3 J
0.5 U
0.5 U
1.4 J
1.4 J
VP 109
50
55
1
18 J
10 J
880
8 80
290
290
190
190
63
63
4.7 J
4.7 J
VP 109
65
70
1
1.3 J
1.3 J
51
5J
11
11
7
7
1.2 J
1.2 J
1.3 J
1.3 J
VP 109
85
90
1
0.5 U
0.5 U
24
24
13
13
4.S J
4,6 J
0.78 J
0.78 J
2 U
2 U
VP 109
110
115
1
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
0 5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP110
35
40
1
0.57 J
0 57 J
14
14
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP110
50
55
1
5.6
5.6
120
120
8.1
8.1
6
6
0.9 J
0.9 J
10
10
VP110
65
70
1
1.5 J
1.5 J
33
33
9 3
3.3
6 5
6.5
1.1 J
1.1 J
3.7 J
3.7 J
VP110
85
90
1
3.8 J
3.8 J
130
130
9.8
9.8
20
20
1.9 J
1.9 J
9.7
9.7
VP110
105
110
1
5 U
5 U
1400
1400
130
130
300
300
20 J
20 J
20 U
20 U
VP111
35
40
1
0.5 U
0.5 II
20
20
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP111
50
55
1
2.9 J
2.9 J
100
100
8.8
8.8
6.4
6.4
0.5 U
0 5 U
2 U
2 U
VP111
65
70
1
2.7 J
2.7 J
59
59
2.1 J
2.1 J
3.8 J
3.8 J
0.5 U
0.5 U
2.3 J
2.3 J
VP111
85
90
1
3.1 J
3.1 J
200
200
15
15
24
24
0.72 U
0.72 U
3.7 J
3.7 J
VP111
110
115
1
3.1 U
3.1 U
910
910
250
250
220
220
44
44
13 U
13 U
VP112
35
40
1
0.5 U
0.5 U
1.4 J
1.4 J
2 U
2 U
0.5 U
0.5 U
0.5 U
0.5 U
2 U
2 U
VP112
50
55
1
2.1 J
2.1 J
270
270
81
81
29
29
69
63
8.8 J
8.8 J
VP112
65
70
1
1.1 J
1.1 J
26
26
4 J
4 J
3.4 J
3 4 J
0.5 U
0.5 U
2.7 J
2.7 J
VP112
85
90
1
4.2 J
4.2 J
280
280
24
24
42
42
3.3 J
3.3 J
13
13
VP112
105
110
1
11 J
11 J
1400
1400
130
130
250
250
23 J
23 J
20 U
20 U
WCC-1A
117
132
0.08 UJ
1 U
8
16 J
3.5 J
6 J
29 J
4.6 J
1.4 J
1.8 J
0.08 UJ
2 U
WCC-1B
51
66
2.2 J
20 J
92
1400 J
74
460 J
51
390 J
6.6
22 J
63 J
200 J
WCC-2
38
48
1
1 U
1 U
4.1
4.1
1 U
1 U
1 LI
1 U
1 U
1 U
1 U
1 U
WCC-3
35
45
1
1 U
1 u
1.5
1.5
1 U
1 u
1 U
1 U
1 U
1 U
1 U
1 U
WCC-5
36
56
0,75 J
1.4 J
14
31
2 J
4,5
1.5 J
3.4
0.47 J
1.1
0.83
2 U
WCC-6
50
70
1
1 U
1 u
17
17
1 U
1 U
1 U
1 U
1 U
1 u
1 U
1 U
WCSB-9
25
45
1
4.3 J
4.3 J
33
33
0.94 J
0.94 J
1 U
1 u
1 u
1 u
1 U
1 U
Notes.
Bold and highlight indicates contaminant was detected abme cleanup level
OU 1, Weil 12A
107
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108 South Tacoma Channel Superfund Site Five-Year Review
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2. South Tacoma Field, Operable Unit 4
2.1. Introduction
This is the third five-year review for the South Tacoma Field, OU 4 (EPA ID No. WAD980726301) of
the South Tacoma Channel (STC) Superfund site located in Tacoma, Washington. The STC Superfund
site also includes Well 12A (OU 1) and Tacoma Landfill (OU 5/6). Each STC OU is treated as a separate
site but for purposes of Five-Year Reviews, all three are being submitted together under one cover. The
triggering action for this review is the date of the previous Five-Year Review in September 2008. The
Five-Year Review is required due to the fact that hazardous substances, pollutants, or contaminants
remain at the site at levels above those that would allow for unlimited use and unrestricted exposure.
2.1.1. Purpose
The purpose of five-year reviews is to determine whether the remedy at a site is protective of human
health and the environment. The methods, findings, and conclusions of reviews are documented in Five-
Year Review reports. In addition, Five-Year Review reports identify issues found during the review, if
any, and recommendations to address them.
2.1.2. Authority
The United States Environmental Protection Agency (EPA) is preparing this five-year review pursuant to
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) §121 and the
National Contingency Plan (NCP). CERCLA §121 states:
If the President selects a remedial action that results in any hazardous substances,
pollutants, or contaminants remaining at the site, the President shall review such
remedial action no less often than each five years after the initiation of such remedial
action to assure that human health and the environment are being protected by the
remedial action being implemented. In addition, if upon such review it is the judgment
of the President that action is appropriate at such site in accordance with section
[104] or [106], the President shall take or require such action. The President shall
report to the Congress a list offacilities for which such review is required, the results
of all such reviews, and any actions taken as a result of such reviews.
The EPA interpreted this requirement further in the NCP; 40 CFR §300.430(f) (4) (ii) states:
If a remedial action is selected that results in hazardous substances, pollutants, or
contaminants remaining at the site above levels that allow for unlimited use and
unrestricted exposure, the lead agency shall review such action no less often than
every five years after the initiation of the selected remedial action.
With oversight from the EPA Region 10 Remedial Project Manager, the United States Army Corps of
Engineers (USACE), Seattle District conducted a five-year review of the remedial actions implemented at
the South Tacoma Field (STF) OU in Tacoma, WA. This review was conducted from January 2013
through June 2013. This report documents the results of the review.
OU 1, Well 12A
109
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2.2. Site Chronology
Table 2-1 lists major activities and milestones related to this site.
Table 2-1. Chronology of Site Events
Event
Date
EPA issued a Record of Decision (ROD) for South Tacoma Field.
September 29, 1994
A Unilateral Administration Order (UAO) was issued for remedial design
and action - soil and groundwater contamination.
January 1996
A Consent Decree for remedial design and action superseded the UAO.
January 1997
EPA conducted initial wetland monitoring.
January 1997
Tacoma City Light completed remedial design.
January 1997
Tacoma City Light initiated remedial action (RA).
August 1997
A wetland investigation was conducted.
March 1998
An RA work plan for remaining areas was completed.
April 1998
The RA for remaining areas began.
June 10, 1998
An additional wetland investigation was conducted.
April 1999
Final inspection for the RA was performed.
July 20, 1999
Construction was completed (a Preliminary Closeout Report was issued).
September 1999
An Explanation of Significant Differences (ESD) for groundwater was
issued.
September 29, 1999
A Final Site Development & Institutional Controls Plan and Operations &
Maintenance Plan (including groundwater monitoring) were submitted.
March 2000
An RA report for soils was approved.
September 2000
The first Five-Year Review was completed.
June 2003
A Certificate of Completion was issued for soils.
September 2003
The Final Closeout Report for STF Soils was issued.
February 24, 2005
A Partial Delisting from National Priority List (NPL), for STF Soils, was
completed.
June 15, 2005
The second Five-Year Review was completed.
September 2008
2.3. Background
2.3.1. Physical Characteristics
The site is located in Tacoma, Pierce County, Washington, between South 36th Street on the north and
South 56th Street to the south, and from Tyler Way on the west to Adams Street on the east (Figure 2-1).
110
South Tacoma Channel Superfund Site Five-Year Review
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The STF OU is approximately 260 acres. The area's elevation is lower than surrounding upland areas by
as much as 150 feet on the west. The southern half of the site contains industrial and commercial
facilities; the northern and western portions are primarily open grass fields. The site includes a former
swamp and lake bed that has been filled and covered with grass overtime. A small wetland is present in
the northern portion of the site.
Storm sewer outfalls discharge water onto the north end of the site that is conveyed across the western
portion in an open channel. Water is not usually present in the southern portion of the channel except in
response to heavy rains. However, the channel continues along Madison Street until it feeds into a storm
drain culvert 150 feet north of South 56th Street.
The site is located within the South Tacoma Groundwater Protection District, which is a special zoning
overlay district managed by the Tacoma Pierce County Health Department (TPCHD). The City of
Tacoma operates several drinking water wells within a half mile of the site (Wells 2B/C, 4A, 6B, and
11A) that are used to augment the City's drinking water supply during peak demand periods.
2.3.1.1 Site Geology
Due to the historical industrialization of the site and subsequent demolition of most pre-existing
structures, most of the near-surface soil at the site has been disturbed. Despite the grading that has
occurred over much of the site, natural processes have resulted in the formation of a thin topsoil (six
inches or less in thickness) in these areas. Beneath this topsoil, fill materials have been mixed with natural
soils. Fill areas are generally indistinguishable from other areas underlain by naturally deposited
sediments. Fill materials generally ranged from 1 to 3 feet in thickness; however, some areas of the site
contain fill materials up to 15 feet thick.
Natural soils beneath the fill materials are part of sequence of glacial and interglacial deposits from the
most recent glaciations. Several distinct channels have been cut into these deposits by high velocity
glacial meltwater, one of which is the South Tacoma Channel over which the site is situated. Where
saturated, the coarse sands and gravels associated with these deposits make them conducive to high
aquifer yields.
2.3.1.2 Hydrogeology
The upper unconfined aquifer at the STF site occurs within the Colvos Sand unit, which represents
advance outwash sands and gravels that were deposited from meltwater streams along the leading edge of
the glacier during its southward advance. The top of the upper aquifer was encountered at depths ranging
from near ground surface (in the Former Swamp/Lakebed area, which is shown on Figure 2-2) to
approximately 35 feet below ground surface in the southeastern portion of the site. The depth to the upper
aquifer varies seasonally, by as much as ten feet, over much of the site. These seasonal variations in depth
to the upper aquifer are dependent on climatic conditions and pumping of the City of Tacoma drinking
water production wells located just east of the site. During times when the City of Tacoma is not
pumping, water level data indicates the formation of a potentiometric "mound" in the upper aquifer in the
southern portion of the site.
OU4, South Tacoma Field
111
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2.3.1.3
Hydrology
Although no perennial creeks, streams, or rivers flow through the STF site, a surface water (storm water)
drainage channel is located below the bluff along the western portion of the site. The primary source of
surface water entering this drainage channel is storm water runoff from residential and industrial areas
that discharge from two storm drain outlets (i.e., northern and southern outfalls) along the northwest
boundary of the site. The storm drain system is owned and operated by the City of Tacoma. Information
gathered during the RI indicates that storm water in the channel does not typically flow off-site as surface
water, except during major rainfall events. Instead, surface water dissipates by evaporation, transpiration,
and infiltration downward through soil and sediment to recharge the upper aquifer. Surface water that
leaves the STF site discharges from the trunk storm drain to the Flett Creek storm basin approximately
1.4 miles south of the site. Approximately 3 miles farther downstream, Flett Creek discharges into
Chambers Creek, which leads to Chambers Bay on Puget Sound.
A perennial wetland and a possible remnant of the South Tacoma Swamp is located along the on-site
drainage channel. The wetland and swamp remnant are primarily supported by storm water runoff from
the surface channel. These areas contain standing water through most of the year and support perennial
wetland and riparian woodland ecosystems.
2.3.2. Land and Resource Use
The site is currently zoned for commercial/industrial use with the exception of an 18 acre strip along the
western border which is zoned for residential-commercial transitional use. The western side of the STF
site, generally in the area of the old airport, is also used for casual recreation (e.g., biking, dog walking,
and flying model airplanes) and illegal dumping of household waste. Businesses recently operating on the
southern half of the STF site included Pioneer Builders Supply, General Plastics, and Industrial Properties
which leases warehouse, office, and yard space to businesses. A portion of the BNSF right-of way, which
comprises the eastern boundary of the STF site, was recently transferred to Sound Transit. The right-of-
way extends northward through the northern boundary of the site. Residential properties are located uphill
from and just off the northwest side of the site.
Since 2003, the three businesses existing at the south end of the site have expanded operations.
Burlington Way was the primary public access to the site until the City completed a new access at South
50th Street, which opens the site up to traffic from South Washington Street and South Tacoma Way.
Burlington Northern Sante Fe (BNSF) Railroad owns the majority of the site.
2.3.3. History of Contamination
A variety of industrial and commercial operations have occupied different portions of the site in the past
hundred years. Figure 2-3 shows historic use across the site and general areas of contamination. The
South Tacoma Car Shops area operated as a railroad vehicle manufacturing and repair facility from 1892
to 1974. The area was used for manufacturing, repair, and maintenance of railroad equipment including
the cleaning and dismantling of rail cars. Foundry facilities operated on-site from 1890 through 1980. An
iron foundry produced iron wheels until 1957. A brass foundry produced journal bearings composed
primarily of lead, tin, copper, zinc and antimony until 1980. Aircraft maintenance and refueling
operations were performed at the South Tacoma Airport from 1936 to 1973. A lake was located beyond
112
South Tacoma Channel Superfund Site Five-Year Review
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the south end of the former runway and, in the late 1940s, was used by seaplanes. A variety of filling
activities occurred during the history of the site. Foundry, construction, and domestic wastes reportedly
were disposed of as fill material in the former swamp/lakebed area. In the 1930s and 1940s portions of the
site reportedly were used as unauthorized dumping areas for household and commercial wastes.
In addition to potential historic contaminant sources, several present day industrial facilities have
contributed to the contaminant source areas. Tacoma Public Utilities (Tacoma City Light) has operated a
maintenance and repair facility at the northernmost end of the STF site since 1953. The property is
covered with asphalt pavement and buildings. Storm water runoff from the property currently drains to
modified dry wells that have soil bottoms and inter-connecting piping leading to the City of Tacoma's
storm drainage system.
Pioneer Builders Supply purchased land in the southeast portion of the site for the construction of a
warehouse and office in 1988. Pioneer used two underground storage tanks (USTs) for about five years to
store gasoline and diesel fuel. During removal of these tanks in 1991, petroleum contamination was
discovered in surrounding soils. Reportedly, all visible soil contamination was removed during the tank
removal. In addition, three other USTs were discovered in the northeast corner of the Pioneer Builders
Supply property in 1990 and were subsequently removed. Soils that were visibly contaminated were
removed; however, excavation did not occur below groundwater level.
2.3.4. Initial response
In 1990, the EPA signed a Consent Order with the Potentially Responsible Parties (PRPs) to conduct a
Remedial Investigation and Feasibility Study (RI/FS) at the site. During the RI, contamination was
identified at the former railroad maintenance area, the Tacoma Public Utilities area, the Pioneer Builders
Supply property, and the Amsted property (former foundry area). The Preliminary Closeout Report
(Long-Term Remedial Action), prepared and issued by EPA in September 1999, contains a detailed
summary of what types of contamination were found at various concentrations and locations across the
site. Surface soils, and to a lesser extent subsurface soils in the rail yard and foundry areas, were
contaminated with high levels of lead, arsenic, copper and zinc. Metal concentrations in surface soil
samples from the former swamp/lakebed area were found to be elevated, but to a lesser degree than in
samples from the more active industrial areas.
At the foundry area on the south end of the site (Amsted property, see Figure 2-2), a relatively small
volume of nearly immiscible, heavy fuel oil was found on the surface of the water table. At the Tacoma
City Light Property on the north end of the site, elevated concentrations of polyaromatic hydrocarbons
(PAHs), polychlorinated biphenyls (PCBs) and several other organics were detected in subsurface soils at
and underlying some of the dry wells. At Pioneer Builders Supply, also on the south end of the site
opposite Amsted, elevated concentrations of 1,2,4-trichlorobenzene, PCBs, petroleum hydrocarbons
(TPH), benzene, ethylbenzene, toluene, and xylenes (BETX) were found in subsurface soil in the
unsaturated zone beneath and immediately surrounding the location where the three USTs were removed.
Benzene, ethylbenzene, and 1,1,2-trichloroethane (TCA) were detected above maximum contaminant
levels (MCLs) in groundwater at this site.
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2.3.5. Basis for Taking Remedial Action
The human health risk assessment (HHRA), as presented in the ROD, evaluated risks due to
contamination in the soil, groundwater, surface water and sediment (in ditches). The routes of exposure
included soil ingestion, skin contact with soil, and ingestion of groundwater. The HHRA considered the
risks posed by ingestion and direct contact based on an industrial use scenario. Surface and sub-surface
soils that might be carried by wind, surface water runoff, and earth moving activities were also
considered. Contamination carried off-site by surface runoff could reach either Chambers Creek or Flett
Creek (located to the south of STF) via the storm water drainage ditch on the west side of the site. It was
also possible that Tacoma's drinking water aquifer could be threatened by the surface water runoff or by
its hydrologic connection to groundwater at the site.
During the comment period for the ROD, it was discovered that an area of about 18 acres on the western
portion of the site was zoned Residential-Commercial Transitional District. Based on this information,
EPA determined that residential cleanup levels would apply. In conjunction with the ROD, the Agency
for Toxic Substances and Disease Registry (ATSDR) issued a public health assessment for the site which
reached the same conclusions as the ROD.
For surface soil ingestion under both the residential and industrial scenarios, excess cancer risks (greater
than lxl0"4) and hazard quotients greater than 1 for non-cancer risks were found to be present. Risks were
primarily driven by arsenic, PCBs, and PAHs. Lead was also noted as present at levels above the standard
for soil at industrial properties. In addition, considering standards for both industrial and residential
properties, excess cancer risk was present for the groundwater pathway.
The results of the Ecological Risk Assessment indicated that potential chemical impacts from on site
contaminants to the plant species of the grassland were small. EPA also determined that levels of
contaminants in the water and sediment in the wetlands/drainage channel were not unusual for urban
wetlands with similar water quality problems. The wetland area was determined to serve a beneficial use
as a filter for urban storm water runoff.
As described in the ROD, the STF site was broken down into three areas for remediation: STF soils,
Pioneer Builders Supply, and Tacoma City Light drywells. Contaminants of concern (COCs) at these
areas were identified as shown in Table 2-2.
Table 2-2. South Tacoma Field Contaminants of Concern
Area
Soil COCs
Groundwater COCs
STF Soil
Aluminum
NA
Aldrin
Antimony
Carcinogenic PAHs
Arsenic
Beryllium
3,3 -Dichlorobenzidine
Copper
PCBs
Lead
Pentachlorophenol
Manganese
Zinc
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Area
Soil COCs
Groundwater COCs
Pioneer Builders Supply
Benzene
1,1,2-Trichloroethane
Toluene
Naphthalene
Ethylbenzene
Benzene
Xylenes
Toluene
TPH
Ethylbenzene
Xylenes
TPH
Tacoma City Light Dry
Wells
Aldrin
3,3 -Dichlorobenzidine
Carbazole
PCBs
Carcinogenic PAHs
Pentachlorophenol
1,4-Dichlorobenzene
NA
NA - not applicable
2.4. Remedial Actions
The ROD was issued on September 29, 1994 and utilized a combination of treatment, containment and
institutional controls for the contaminated soil throughout the site and treatment of contaminated
groundwater at Pioneer Builders Supply. An ESD was issued on August 29, 1999 after the UST and
contaminated soils at Pioneer Building Supply were removed. The ESD changed the treatment of
contaminated groundwater at Pioneer Builders Supply to MNA.
2.4.1. Remedial Action Objectives
The following Remedial Action objectives are specified in the ROD for STF:
• The objective of the subsurface soil cleanup goals is to prevent further groundwater contamination.
• The objective of the groundwater cleanup goals is to reduce total excess cancer risk from all
carcinogens to no greater than 1 in 100,000 (10~5) and a Hazard Index that will not exceed 1.
2.4.2. Remedy Description
The following description of the selected remedy is taken from the ROD and ESD.
STF Soils
• Excavate and solidify contaminated soil (except for PCB contaminated soil) that exceeds hot spot
concentration thresholds. Treated soil shall be placed back on site under a soil or asphalt cap.
• Soil contaminated with PCBs above 50 parts per million (ppm) was found in only one location at
Pioneer Builders Supply. If additional sampling at this location confirms PCB concentrations above
50 ppm, then these soils shall be excavated and either incinerated at an approved, off-site incinerator
or disposed off-site at a permitted hazardous waste disposal facility.
• Excavate, consolidate on-site and contain (cap) soil which exceed capping levels (Model Toxics
Control Act (MTCA) Industrial Method A). The required excavation of soil would be limited to a
maximum of one foot. If, after excavating a foot of soil, an area is still contaminated above MTCA
industrial soil cleanup levels, the area will be capped. The PRP may continue excavating until
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contaminants in soil are below industrial cleanup levels, and thus avoid the requirement to cap in that
area. Contaminated soils shall be capped with either soil or asphalt.
• Implement institutional controls (e.g., deed restrictions, access restrictions, fencing), to prohibit
activities that may lead to exposure to contaminants and to protect capped areas.
• Conduct groundwater monitoring, including monitoring of the petroleum hydrocarbon contamination
found at the Amsted property. This is required to ensure that groundwater levels stay below federal
drinking water or MTCA based cleanup standards. Monitoring of the storm water run-on, runoff,
surface water, and sediment in the wetland/drainage channel is also required. The monitoring program
shall be reviewed every five years to determine whether additional actions are required or whether the
monitoring program should be modified or discontinued.
Pioneer Builders Supply
• The ROD originally required implementation of air sparging and in situ vapor extraction in the
vicinity of Pioneer Builders Supply to clean up contaminated subsurface soil and groundwater to
achieve cleanup levels. However, after source removal contaminant concentrations in groundwater
decreased and an ESD determined that groundwater monitoring for natural attenuation, rather than
active treatment, was appropriate.
• Implement institutional controls in the form of restrictions on groundwater use to non-drinking water
purposes in the vicinity of Pioneer Builders Supply. This restriction shall continue until groundwater
cleanup levels, set at the federal drinking water standards, are achieved throughout the contaminant
plume and MTCA cumulative risk requirement of risks no greater than 1 in 100,000 and a Hazard
Index no greater than 1 are also achieved.
• Conduct groundwater monitoring as part of the cleanup remedy for this portion of the site. The
monitoring program shall be reviewed every five years to determine whether additional actions are
required or whether the monitoring program could be modified or discontinued.
Tacoma City Light Dry Wells
• Excavate contaminated soil with PCB concentrations above 50 ppm or endrin concentrations above
0.13 ppm and transport the soil off-site for incineration.
• Excavate and transport to an off-site, permitted hazardous waste disposal facility all soil with PCB,
PAH and other chemical concentrations above the MTCA Method B residential clean up levels.
2.4.3. Remedy Implementation
STF Soils
The remedial action for STF soils began in June 1999. The following work was conducted in accordance
with the ROD and the Consent Decree:
• Approximately 6,300 tons of soil exceeding hot-spot concentrations were excavated and treated (i.e.,
stabilized with a phosphate-based reagent). These soils were consolidated on-site and covered with a
clean soil cap.
• 15.4 tons of soil at Pioneer Builders Supply with PCBs exceeding 50 mg/kg were excavated and
disposed off-site.
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• 113,607 tons of soil with contaminant concentrations between the level that would have required
capping and the hot-spot level were consolidated and capped.
• An estimated 13.7 acres of the STF OU was capped.
• Buried tanks and drums and their contents were removed and disposed. Associated contaminated soils
and solid wastes were also removed and disposed of at a permitted facility.
• Sub-surface soils contaminated at levels above those that would require capping were capped where
excavation and consolidation were not cost-effective.
• Institutional controls (ICs) prohibiting residential development were implemented. A parcel map
showing the areas where deed restrictions were recorded is shown on Figure 2-4.
• Site access controls limiting exposure to caps were installed (e.g., fencing, warning signs on
consolidation areas, grid-area markers for surveying integrity of capped areas over time).
• During construction, air was monitored to assess airborne contaminant concentrations in the work
area and at site boundaries.
Only three minor deviations from the ROD and approved remedial design (RD) occurred. First, the ROD
called for Portland cement as a stabilizing agent; instead, a proprietary phosphate-based reagent was used
to render metal contaminants stable and insoluble. Second, because the RD assumed Portland cement as
the stabilizer, a retaining wall and storm water drainage were designed for the Amsted property. However,
the volume of soil needing treatment was smaller than expected since cement was not used, and the
retaining wall and associated storm water drainage were unnecessary. Finally, because near-term
development was expected on the STF portion of the site, all excavated soil was not fully replaced
because backfill from development was anticipated to fill the remaining excavated volume. (Note a
minimum of six inches of topsoil was placed over all soils requiring a cap.)
Some small areas of contamination, where concentrations exceeded levels that would require capping,
could not be excavated because they were beneath active rail lines. These grid-areas were documented
and are shown on Figure 2-5. The Site Development and Institutional Control Plan (SDICP) contains
operation and monitoring requirements for these areas to manage exposure during rail maintenance or
construction or utility work.
There are three areas of consolidated soil contamination, one at the northern portion of the STF and two at
the southern end (Figure 2-6). Of these three areas, only the northern area was completely fenced as part
of the remedial action. One of the southern consolidation areas (Amsted) was fenced on three sides of the
parcel that were easily accessible from South Proctor Street, while the third side was not fenced because
steep slopes naturally limit access and trespass. Exposure is controlled by site use on the Amsted area
which is parking and storage for various items (truck containers, logs). For the northern and Amsted
areas, future development plans allow redesign and/or removal of the fences. The southernmost area of
consolidation was not fenced as part of the remedial action. Due to its visibility from South 56th Street,
which is a major thoroughfare, this area is much less attractive for use by transient people than other parts
of the site which are open to less-traveled public right-of-ways where post-remedial soils are a mix of
conditions suitable for industrial use/exposure as well as unrestricted use.
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Pioneer Builders Supply
The ESD determined that groundwater monitoring for natural attenuation, rather than aggressive
treatment, was appropriate because contaminant concentrations were decreasing and the source (USTs)
had been removed. Groundwater sampling is conducted annually at Pioneer Builders Supply to monitor
the effectiveness of the natural attenuation remedy. The ROD established cleanup levels for soils in 1994;
however, it is not clear if these levels were achieved during the UST removals in 1990 and 1991. At the
time the USTs were removed (during the RI), visibly contaminated soils were excavated but not below
the groundwater level. Confirmation sample data from the UST removal actions were not assessed so this
FYR cannot confirm that soil cleanup levels established afterward in the ROD were met.
Tacoma City Light Dry Wells
In 1997, Tacoma City Light remediated their dry well contamination in accordance with the ROD,
choosing to perform a more aggressive cleanup than pursued for other areas of the site. Soils
contaminated with 50 mg/kg or more PCBs and 0.13 mg/kg or more endrin were excavated and
incinerated off-site.
Wetland Drainage Channel
As required in the ROD, EPA conducted two rounds of groundwater, surface water, and sediment
sampling in the drainage channel in November 1996 and September 1997 to characterize surface water
run-on and determine if the run-on has affected on-site sediment or groundwater. Select surface water and
sediment sampling locations were re-sampled in August and November, 1998. Sample results confirmed
that surface water and sediment concentrations were similar to those in other urban runoff channels. The
later samples indicated lead was present in sediment at a concentration of 913 mg/kg, compared to the
soil- capping-required level of 1,000 mg/kg. Arsenic (maximum = 7.57 micrograms per Liter [jxg/L]) and
carcinogenic PAHs (cPAHs; 0.13 |ig/L) were also detected at levels above the MTCA Method B criteria
for surface water of 0.09 |ig/L and 0.03 |ig/L for arsenic and individual cPAHs, respectively. EPA
determined that the source of surface water and sediment contamination found in the wetland and
drainage channel resulted from storm water run-on from two City of Tacoma drains and no additional
action was required.
2.4.4. Systems operations/Operations & Maintenance
The 2000 Operation & Maintenance (O&M) Plan addresses the requirements presented in the ROD and
the Consent Decree. The O&M Plan addresses ongoing monitoring and maintenance of remediation
activities that were completed at the site in accordance with the RD and the Remedial Action Work Plan.
Information collected during implementation of the O&M Plan is used to aid in the evaluation of the
effectiveness of the remedy. Routine O&M activities consist of inspecting the site, assessing potential
changes in site conditions that may result in exposure to contaminated soil, and correcting deficiencies.
2.4.4.1 Systems Operations/O&M Requirements
Following remedial actions, PRPs were required to perform inspections of the remedy in accordance with
the O&M Plan. Monitoring activities include:
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1. Inspection/Maintenance Activities:
• Inspecting for signs of unauthorized entry, vandalism or compromise of the perimeter fence at the
Amsted Property and BNSF Dismantling Yard;
• Inspecting soil caps for signs of failure;
• Inspecting and identifying eroded or blocked drainage courses; and
• Inspecting monitoring wells for vandalism.
2. Groundwater Monitoring:
• Annual monitoring of STF wells to assess the impacts of the consolidated areas on groundwater; and
• Annual monitoring of Pioneer Builders Supply wells to assess the effectiveness of natural attenuation.
2.4.4.2 Systems Operations/O&M Operational Summary
The following issues have been noted in the last five O&M reports from 2008 to 2012:
• Monitoring well STM-1A was damaged prior to the site inspection in 2008. The well has not been
replaced or closed.
• Monitoring well NMW-8A was reported as damaged in the 2010 site inspection. It was possible to
collect a sample from well NMW-8A due to a higher than average groundwater level that year.
However, future sampling will likely be inhibited due to the extent of damage.
• Fencing damage and subsequent repairs were reported in the 2008 Progress Report. The fence around
the site is now in good condition and continues to be monitored for any damage.
• Trespassing and illegal dumping was noted as a continual problem from 2008 to 2012. While repairs
to fencing helped to deter trespassing, signs of dumping and use by transient people still remain
outside of fenced area..
• Grid-area marker 558 could not be located during the 2008 site inspection and was subsequently
replaced.
2.4.4.3 Summary of Costs of System Operations/O&M Effectiveness
No operations and maintenance costs were available for the South Tacoma Field OU.
2.5. Progress Since the Last Five-Year Review
2.5.1. Protectiveness statements from last review
The protectiveness statement in the last Five-Year Review stated:
The remedy at South Tacoma Field is not protective because of the following issues:
• In the short term there is an immediate threat to transients using open unused areas of the
site based on the potential for direct contact with remaining contaminated soils that exceed
the standard for unrestricted use on some portions of the site. The pending
commercial/industrial development will significantly reduce the amount of open space
currently attractive to transients;
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• The MNA groundwater remedy at Pioneer Building Supply has not met the cleanup goal
within the time specified in the ROD. It may be that residual, subsurface soil contamination is
contributing to the groundwater plume; it may also be that recent paving of large areas in
this vicinity is affecting natural attenuation. If residual soil contamination is present, ICs may
be required to prevent contact with these soils (e.g., excavation in future construction); and
• Migration of the contaminated groundwater above the cleanup levels at Pioneer Building
Supply may not be controlled.
The following actions need to be taken to ensure protectiveness:
• Work with BNSF to determine actions regarding transients living on open, unused areas of
the site, including access controls along public right-of-ways;
• Develop and implement a revised groundwater monitoring program. Use new groundwater
and soil data to assess time frame needed for MNA or modifications to the remedy.
Modifications to the remedy may include ICs for residual soil contamination, ifpresent; and
• Evaluate new groundwater data at Pioneer Building Supply to determine if migration of
groundwater plumes is controlled.
2.5.2. Status of recommendations and follow-up actions from last review
Recommendation 1: Prepare a revised Work Plan for well installation and sampling.
Status: Not Completed. A work plan for well installation and sampling has not been developed.
However, well replacement and closeout of some wells is planned for 2013. Sampling continues to be
performed per guidelines in the O&M Plan.
Recommendation 2: Evaluate all new and existing data to assess time frame for effectiveness of MNA,
or need for additional action.
Status: Not Completed. The ESD recommended the use of MNA in 1999. In 2000 MNA was analyzed
for effectiveness. No additional action, other than annual monitoring, has been taken in support of MNA.
Recommendation 3: Evaluate remaining soil contamination and verify soil cleanup levels have been
achieved. This may include review of historical data and/or collection of new data.
Status: Not Completed. This action has not been completed. Groundwater concentrations have been
decreasing during the last five years and recent sampling indicates that all contaminants are below current
MTCA cleanup levels. This indicates that residual soil contamination may not be present at elevated
concentrations as previously thought. Continued groundwater monitoring is necessary to confirm this
decrease. If groundwater concentration increases occur, an evaluation of residual soil contamination
should be completed.
Recommendation 4: Determine need for ICs for soil based on soil characterization data.
Status: Not Completed. No action has been taken to review changes in ICs for soil. Groundwater
concentrations at Pioneer Builders Supply have decreased. If an increase is observed in the future and
residual soil contamination is present, additional ICs for soil in this area may be needed.
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Recommendation 5: Replace well STM-1A and complete minimum one additional year of sampling.
Status: Ongoing. BNSF has developed a work plan for replacement of well STM-1A but have yet to
initiate construction.
Recommendation 6: Conduct fence repairs (fences may be removed as site is developed).
Status: Completed. Fences have been repaired around the consolidation areas and new fencing has been
installed at the central portion of the site and at the primary entrance.
Recommendation 7: Verify status of capped areas in grid-areas 879, 785, and 767.
Status: Completed. Capped areas have been inspected during the annual site inspections and have been
determined to be in good condition and mostly undisturbed.
Recommendation 8: Conduct an optimization of the site-wide groundwater monitoring program
including a determination of wells critical for assessing the remedy.
Status: Not Completed. There has been no evaluation or changes to the monitoring program since the
last FYR. However, well replacement and closeout of some wells is planned for 2013.
Recommendation 9: Work with BNSF to determine action regarding transients living on property.
Status: Completed. Repairs and installation of new fencing have significantly decreased transient use of
the site. BNSF also worked with the City of Tacoma to relocate transients and meth labs away from the
site.
Recommendation 10: Review need for changes in administrative ICs for EPA access and restrictive
covenants.
Status: Not Completed. No action has been taken to review changes in ICs. However, site fencing has
been improved and transient access appears to be minimal.
2.6. Five- Year Re view Process
2.6.1. Administrative Components
BNSF Railroad was notified of the initiation of the Five-Year Review in February, 2013. The Five-Year
Review team was led by Kris Flint of EPA, Remedial Project Manager (RPM), and included Kristen
Kerns (Physical Scientist) and Sharon Gelinas (Hydrogeologist) of the USACE Seattle District.
From January to June 2013, the review team established the review schedule whose components included:
• Community Involvement;
• Document Review;
• Data Review;
• Site Inspection;
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• Local Interviews; and
• Five-Year Review Report Development and Review.
2.6.2. Community Involvement
A public notice announcing the five-year review for the Site was published April 25, 2013 in the Tacoma
News Tribune.
2.6.3. Document review
This FYR included a review of relevant, site related documents including annual progress reports and
applicable soil, groundwater, and surface water cleanup standards. A complete list of the documents
reviewed can be found in Appendix 2-A.
2.6.4. Data Review
STF and Amsted Groundwater Monitoring
Annual groundwater monitoring is used to assess impacts of the soil consolidation areas on local
groundwater. Groundwater data provided in the 2008 to 2012 annual reports were reviewed. Sampling
associated with monitoring reports for 2008, 2009, and 2011 occurred in January 2009, January 2010, and
January 2012 respectively. Sampling associated with the 2010 and 2012 reporting years were conducted
in December 2010 and December 2012, respectively. All STF and Amsted wells were analyzed for total
lead. In addition, the Amsted wells were also analyzed for TPH as oil and diesel, and PAHs. Groundwater
monitoring data are presented in Appendix 2-E and well locations are shown on Figure 2-6.
At the Amsted property, TPH, PAHs, and lead are analyzed to assess impact of remaining petroleum
hydrocarbon contamination. PAHs were not detected at concentrations above laboratory reporting limits
during the last five years. TPH as diesel and oil and total lead were detected during the last five years, but
at concentrations below the cleanup levels.
Although the ROD does not evaluate lead concentrations for drinking water, it should be noted that lead
was detected at concentrations above the MTCA A cleanup level of 15 (ig/L. at well STM-3A between
December 2010 and December 2012 with concentrations ranging from 19.9 to 130 (ig/L. Lead
concentrations at well STF-4A also exceeded action levels from January 2010 to December 2012 with
concentrations ranging from 15 to 260 j^ig/L. At well VMW-2 there was one slight exceedance (15.9
(.ig/L) in January 2009. Significant increases in lead concentrations at wells STF-3A and STF-4A were
observed during the December 2012 sampling event. It should be noted that water-use restrictions
currently at the site effectively eliminate the relevant exposure pathway for which the 15 (.ig /L action
level was established. Field parameters were not available for review for this sampling event to
determine if elevated sample turbidity impacted metals concentrations. Groundwater levels during this
sampling event were at some of the highest levels recorded based on a review of available information
from prior monitoring events. This indicates that some contaminated soil in the vadose zone may be
exposed to continuous saturation that has not occurred in the past, potentially resulting in some particulate
or soluble material migrating into the groundwater. Monitoring at the STF wells should continue to
determine if concentrations remain elevated. In addition, the monitoring program should be revised to
evaluate the potential impact of residual soil contamination on groundwater concentrations. Changes
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should include increasing the sampling frequency to twice a year to allow for evaluation of conditions
during both wet and dry seasons.
Pioneer Builders Supply Groundwater Monitoring
Annual groundwater monitoring at Pioneer Builders Supply is used to evaluate the effectiveness of MNA
as a groundwater remediation method. The data provided in the 2008 to 2012 annual reports were
reviewed.
Pioneer Builders Supply groundwater monitoring data are shown in Appendix 2-E and monitoring wells
are shown on Figure 2-7. Well NMW-1A (within the former UST area) is the only well that contained
contaminant concentrations above the cleanup level during the last five years. Concentrations of TPH as
gasoline ranged from 0.22 to 3.19 mg/L, concentrations of TPH as diesel ranged from <0.076 to 0.68
mg/L, and benzene concentrations ranged from < 1.0 to 5.1 (ig/L. It should be noted that the cleanup level
for 1,4-dichlorobenzene (1.82 (ig/L) was based on Ecology's Method B cleanup level from their Cleanup
Levels and Risk Calculations (CLARC) database in 2000-2001, while a review of the current CLARC
database indicated that Ecology has withdrawn the listed cleanup level for this chemical. Concentrations
of 1,4-dichlorobenzene exceeded the old cleanup level, ranging from 1.62 to 3.7 j^ig/L at well NWM-1A;
however, since there is currently no cleanup level, these occurrences of 1,4-dichlorobenzene will not be
considered exceedances.
To evaluate the progress of MNA, trends for contaminant concentrations at well NMW-1A that exceeded
the cleanup level during the last five years were evaluated using the Mann-Kendall test for trend. Table
2-3 shows that when all data between 1999 and 2012 are considered, TPH as diesel and benzene have a
statistically significant decreasing trend and TPH as gasoline is stable.
Table 2-3. Mann-Kendall Trend Test Results, Well NMW-1A
Contaminant
Confidence Factor
Concentration Trend
TPH as gas
81.0%
Stable
TPH as diesel
99.9%
Decreasing
Benzene
99.9%
Decreasing
NMW-1A also has a history of contaminant concentration fluctuations that were thought to be related to
groundwater level fluctuations or groundwater flow direction variations. Figure 2-8 shows TPH as
gasoline and diesel and benzene concentrations were plotted against the depth to groundwater. The data
show that there is no apparent correlation; however, the groundwater flow direction could still influence
contaminant concentrations if there is a residual source remaining in soil. Although contaminant
concentrations found at well NMW-1A during the last sampling event had decreased to below cleanup
levels, continued monitoring is necessary to determine if MNA is truly effective. If future sampling shows
an increase in concentrations, similar to those seen in the historical fluctuations, the impact of potential
residual soil contamination on groundwater concentrations should be investigated. This could include
additional soil and groundwater sampling and an evaluation of groundwater flow variations on
contaminant concentrations.
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City Well Data
The City of Tacoma intermittently operates several drinking water supply wells in the South Tacoma
Channel. The City of Tacoma routinely monitors water quality in their drinking water wells in accordance
with the Safe Drinking Water Act. Wells are sampled at the well head either once every three years or
when the well is turned on for use, whichever is more frequent. In addition, combined water from all
wells is sampled once a year at the point of entry to the distribution system. The STF OU is adjacent to
City drinking water supply Wells 2B/C, 4A, 6B, and 11A. Electronic data from these wells were reviewed
to verify that drinking water has not been impacted by the STF. There were detections of
trichlorofluoromethane, chloroform, and trichloroethylene in well 6B between 2008 and 2011. There were
also detections of trichlorofluoromethane and chloroform in well 11A. In November 2010 there were
detections of xylene, toluene, and ethylbenzene in well 2C. These detections are believed to be related to
work that was done on a pump system. Follow-up sampling in May 2011 showed no detection of these
chemicals. All concentrations for all wells were below federal MCLs. None of the contaminants in the
City wells appear to be related to the STF OU. As such, there is no current risk from this exposure
pathway. Results from samples collected annually at the point of entry to the distribution system have
remained non-detect for volatile organics.
2.6.5. Site Inspection
Inspection at the site was conducted on March 5, 2013, by the US ACE review team, BNSF Railroad, and
Kennedy Jenks Consultants. Photographs taken during the site inspection are presented in Appendix 2-B.
The completed site inspection checklist is presented in Appendix 2-C. The inspection consisted of
checking the integrity of areas where soil has been capped and vegetation, fencing around the site, and
general land use. During the site visit, several observations were noted:
• The newly installed fence was in good condition and trespassing appeared to be at a minimum.
• Areas of minor dumping were observed in the central and southern portions of the site.
• Approximately three damaged monitoring wells were noted.
2.6.6. Interviews
Nathan Graves and Dean Malte from Kennedy Jenks Consultants for BNSF Railroad, were interviewed
on methods for conducting operations and maintenance activities. Bruce Sheppard from BNSF Railroad
was interviewed regarding the overall status of the site. All interviewees stated that operation and
maintenance at the site was going well and no major problems have been encountered. Interviewees also
commented on significant improvements at the site regarding trespassing since installation of the chain
link fence around the site. Because of low community interest of the site no community members were
interviewed. Interview summaries are provided in Appendix 2-D.
2.6.7. Institutional Controls
Remaining soil and groundwater contamination at the site do not allow for unrestricted use/ unrestricted
exposure, so ICs are required for both media. The SDICP outlines several ICs for the site. EPA is
responsible for monitoring the effectiveness of the ICs, and uses checks on the development status as a
tool to ensure this restriction. BNSF is responsible for the implementation, maintenance, and inspection of
the ICs. The SDICP does not explicitly describe the objectives for the ICs, but it is inferred that they
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South Tacoma Channel Superfund Site Five-Year Review
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include protection against direct contact with soil under industrial uses and prevention of groundwater use
for drinking.
The ICs at South Tacoma Field consist of the following:
• Granting EPA access to monitor and inspect the site
• Limiting land use to industrial purposes
• Assuring maintenance of caps that contain contaminated soils
• Prohibiting groundwater use in the vicinity of Pioneer Building Supply
• Recording restrictive covenants and leases with the Pierce County Auditor
• Notifying EPA of ownership transfers or lease agreements regarding the site
• Developing safety guidelines for future potential site workers
• Developing a fact sheet to distribute to the community
BNSF and Amsted have implemented use restrictions on the property they own. Environmental restrictive
covenants and access easements were filed in 1997 that include the following restrictions: land use shall
be for non-residential purposes, no activities shall disturb contaminated soil or the integrity of the capped
areas, groundwater from the Pioneer Builders Supply property shall not be used for drinking water, and
EPA shall be notified of any conveyance of the property. The access easement allows perpetual access to
the property for implementation of the remedial actions. A title search was not completed as part of this
FYR to confirm that the covenants and access easement was transferred along with any property transfers.
Safety procedures have also been put in place to protect site workers and the public. Consolidated soil
areas are covered with at least 1 foot of clean soil, the northern and central portions of the site have been
fenced, gates are kept locked, and "Keep Out" signs are in place to warn the public. Annual inspections
ensure that these safety procedures remain in place and that the cap integrity remains complete. Fencing
damage noted in the inspection reports has been repaired and trespassing appears to be minimal,
indicating that the safety procedures are working.
2.7. Technical Assessment
2.7.1. Question A: Is the remedy functioning as intended by the decision
documents?
Yes. The remedy appears to be functioning as intended by the decision document. Hot spots have been
removed and contaminated soil has been consolidated on-site. Groundwater monitoring for the STF
consolidation area showed a recent increase in lead concentrations; however, the cause and impact on
remedy effectiveness of this increase has not been evaluated. Groundwater contaminant concentrations at
Pioneer Builders Supply have decreased; however, continued monitoring is necessary to determine if
MNA is effective. Institutional controls are in place to protect future site workers and the public.
Remedial Action Performance
The selected remedy for soil hot spots was excavation and on-site treatment using solidification. For the
remaining contaminated soils in which contaminant levels exceeded capping-required levels, excavation
and capping was conducted. The required access controls (fences, signs, and ecology blocks) to ensure
OU4, South Tacoma Field
125
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cap integrity have been implemented in accordance with the approved design. Additional fencing has
been installed around the northern and central portion of the site and at the main entrance. The fence
surrounding the northern consolidation area has been repaired and access to the capped area is restricted.
The fence at the Amsted consolidation area was also repaired to limit access even though that fence is not
actually part of the remedy. The southernmost consolidation area is not fenced, but does have concrete
ecology blocks meant to prevent vehicle access. The southernmost consolidation area appears to be
mostly undisturbed.
Groundwater monitoring for the STF consolidation areas identified exceedances of MTCA A action
levels for lead at wells STM-3A and STM-4A for the last three sampling events, with a significant
increase in results from the last sampling event in December 2012. Groundwater levels were at some of
the highest recorded and may indicate that contaminated soil in the vadose zone being exposed to
continuous saturation that has not occurred in the past. The groundwater monitoring program for the STF
monitoring wells should be revised to determine if soil contamination is contributing to the elevated lead
concentrations in groundwater. Changes should include increasing the sampling frequency to twice a year
to evaluate conditions during both wet and dry seasons and replacing the damaged STM-1A well.
Contaminant concentrations in the Amsted wells have been below site cleanup levels for all sampled
analytes for seven consecutive years.
The selected remedy for the groundwater at Pioneer Builders Supply is MNA. The 1999 ESD predicted
that COC concentrations would decrease to below cleanup levels within four years (by 2003). All
concentrations were below current MTCA cleanup levels at well NMW-1A (within the former UST
source area) for the first time in December 2012. Well NMW-1A has a history of contaminant
fluctuations that could be associated with groundwater level fluctuations or groundwater flow direction
variations. Continued monitoring is necessary to determine if MNA is truly effective. If future sampling
at Pioneer Builders Supply shows an increase in concentrations, similar to the historical fluctuations, the
impact of potential residual soil contamination on groundwater concentrations should be investigated.
This could include additional soil and groundwater sampling and an evaluation of groundwater flow
variations on contaminant concentrations. While sampling for well NMW-8A at Pioneer Builders has
been possible due to higher than normal water levels in recent years, the damage well should be replaced.
System Operations/O&M
O&M has generally been conducted as designed, with the exception of damage to wells STM-1A and
NMW-8A. This damage prevents sampling at these wells.
Opportunities for Optimization
Opportunities for optimization were not identified during this FYR.
Implementation of Institutional Controls
Institutional controls are in place to prevent direct contact with contaminated soil and prevent
groundwater at Pioneer Builders Supply from being used as drinking water. Significant improvements
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South Tacoma Channel Superfund Site Five-Year Review
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were made to the site with installation of new fencing around the entire northern and central portion of the
site. This has restricted unauthorized access and illegal dumping at the site.
Early Indicators of Potential Issues
There are no early indicators of potential issues.
2.7.2. Question B: Are the exposure assumptions, toxicity data, cleanup levels,
and remedial action objectives (RAOs) used at the time of the remedy
selection still valid?
Yes. Generally, the standards and toxicological values used at the time of remedy selection have remained
unchanged with the following exceptions.
Changes in Standards and TBCs
A review was done to identify any changes in standards that were identified as applicable or relevant and
appropriate requirements (ARARs) in the ROD; newly promulgated standards including revised
chemical-specific requirements (such as MCLs); revised action- and location-specific requirements; and
State standards and TBCs identified in the ROD that bear on the protectiveness of the remedy. Any such
changes were then evaluated to establish whether the new requirement indicates that the remedy is no
longer protective. Table 2-4, and Table 2-6 provide summaries of changes. Generally, the standards and
toxicological values used at the time of the remedy have remained unchanged with the following
exceptions.
Soil. Washington Department of Ecology modified MTCA substantially in 2001 and 2007. MTCA
Method A industrial cleanup levels were used for soil-capping-required levels. The Method A industrial
cleanup levels decreased compared with those in effect at the time the ROD was issued for arsenic (from
200 to 20 mg/kg) and total PAHs (from 20 to 2 mg/kg) during the modification of MTCA in 2001 and
2007 (for PAHs) (see Table 2-4). It is important to note that the updated cleanup level of 2 mg/kg for total
PAHs is based on benzo(a)pyrene. Toxic Equivalency Factors for PAHs were adopted by the Depratment
of Ecology in 2007. Benzo(a)pyrene was identified as the reference chemical for establishing cleanup
levels for total PAHs. Revisions to these criteria were based on the protection of groundwater, so they do
not likely impact the protectiveness of the remedy with respect to direct contact exposure for industrial
workers but may impact protectiveness of groundwater. Ongoing monitoring of groundwater will be
conducted to confirm that groundwater concentrations remain below cleanup levels.
For informational purposes, a comparison of the revised criteria to concentrations reported in the
Remedial Action Report was conducted. There are at least four uncapped grid-areas (535, 537, 789, and
900) that had concentration in soil above the revised total PAH (as benzo(a)pyrene) concentration of 2
mg/kg. Generally, arsenic concentrations in soil are below the revised criteria for this compound.
However, the arsenic detection limit for many samples was 81 mg/kg, four times the revised cleanup level
of 20 mg/kg.
The objective of the subsurface soil cleanup goals at Pioneer Builders Supply was to prevent further
groundwater contamination. MTCA Method A industrial criteria was used for soil cleanup levels;
OU4, South Tacoma Field
127
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however, it cannot be confirmed if remaining soil concentrations meet this criteria. The Method A
cleanup levels have decreased since the ROD was issued the following compounds: benzene (from 0.5 to
0.03 mg/kg), toluene (from 40 to 7 mg/kg), ethylbenzene (from 20 to 6 mg/kg), and xylenes (from 20 to 9
mg/kg). Revisions to these criteria were based primarily on the protection of groundwater. Remaining soil
concentrations at the site should be reviewed in light of these new criteria to determine potential impacts
to the remedy. Data on subsurface soil concentrations were collected during the RI. More recent data is
not available.
Groundwater. At Pioneer Builders Supply, groundwater cleanup levels for benzene, ethylbenzene,
toluene, total xylenes, and 1,2-dichloroethane were based on the federally set MCLs for drinking water.
The cleanup level for naphthalene was based on MTCA Method B.
Table 2-4 compares cleanup levels identified in the ROD and revised MTCA cleanup levels (specifically,
revised default concentrations under Method A and B) for all chemicals detected in groundwater.
Dichlorobenzenes (1,2- and 1,4-) and 1,2,4-trichlorobenzene are contaminants that were not specifically
addressed in the ROD or ESD; however, they are frequently detected at this site and have also been
addressed by revisions to MTCA. Carbon tetrachloride was detected for the first time in January 2008 and
again in 2010 at well NMW-11A and has been included in Table 2-4Table 2-4.
The remedy at Pioneer Builders Supply requires restrictions on groundwater use to prevent it being used
for drinking water until cleanup levels are achieved and the MTCA cumulative risk requirements of no
greater than 1 in 100,000 or a Hazard Index not exceeding 1 are achieved. Since concentrations for some
analytes are still above cleanup levels identified in the ROD, changes to the regulations do not impact
protectiveness of the remedy. However, revised criteria for drinking water will impact the time frame in
which site water use restrictions can be lifted.
Changes in Exposure Pathways
The previous FYR identified exposure to those trespassing on the site, mostly transients. Since
installation of the new fencing at the site this exposure pathway has largely been eliminated. There are no
other changes in exposure pathways at the site.
Changes in Toxicity and Other Contaminant Characteristics
Updated toxicity values for 1,4-Dichlorobenzene and 1,2,4-Trimethylbenzene have resulted in
undetermined standards. Other updates to toxicity values are reflected in revised standards and are
summarized in Table 2-4.
Changes in Risk Assessment Methods
There have been no substantial changes to the standardized risk assessment methods.
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South Tacoma Channel Superfund Site Five-Year Review
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Expected Progress Toward Meeting RAOs
MNA at Pioneer Builders Supply has been slower than originally anticipated, but concentrations are
decreasing and have recently dropped below the cleanup levels. The increase in lead concentrations at two
wells indicates that RAOs for soil have not been completely met.
Table 2-4. Changes in Chemical-Specific Standards
Contaminant
Media
ROD
Cleanup
Level
Standard*
Citation/Year
Arsenic
Soil - STF
Hot Spot
570 mg/kg
Previous
NA
lxlOA-4 risk level using MTCA exposure
assumptions
New
—
—
Lead
Soil-STF
Hot Spot
18000
mg/kg
Previous
NA
Based on cost sensitivity analysis in FS
New
—
PAHs Total
Soil - STF
Hot Spot
50 mg/kg
Previous
NA
Set at 2.5 times the MTCA Method A
industrial
New
—
PCBs Total
Soil - STF
Hot Spot
50 mg/kg
Previous
NA
TSCA requirement
New
—
Copper
Soil - STF
Hot Spot
45000
mg/kg
Previous
NA
Based on leaching to groundwater
New
—
Arsenic
Soil - STF
Capping
200 mg/kg
Previous
200 mg/kg
Method A industrial cleanup level
New
20 mg/kg
Method A industrial cleanup level, 2001
Lead
Soil-STF
Capping
1000 mg/kg
Previous
1,000
mg/kg
Method A industrial cleanup level
New
—
PAHs Total
Soil - STF
Capping
20 mg/kg
Previous
20 mg/kg
Method A industrial cleanup level
New
2 mg/kg
Method A industrial cleanup level as
benzo(a)pyrene, 2007
PCBs Total
Soil - STF
Capping
10 mg/kg
Previous
10 mg/kg
Method A industrial cleanup level
New
10 mg/kg
Method A industrial cleanup level,
assumes mixture is equitoxic, 2007
Benzene
Soil -
Pioneer
Builders
0.5mg/kg
Previous
0.5 mg/kg
Method A industrial cleanup level
New
0.03 mg/kg
Method A industrial cleanup level, 2001
Toluene
Soil -
Pioneer
Builders
40 mg/kg
Previous
40 mg/kg
Method A industrial cleanup level
New
7 mg/kg
Method A industrial cleanup level, 2001
Ethylbenzene
Soil -
Pioneer
Builders
20 mg/kg
Previous
20 mg/kg
Method A industrial cleanup level
New
6 mg/kg
Method A industrial cleanup level, 2001
Xylenes
Soil -
Pioneer
Builders
20 mg/kg
Previous
20 mg/kg
Method A industrial cleanup level
New
9 mg/kg
Method A industrial cleanup level, 2001
TPH
Soil -
Pioneer
Builders
100-200
mg/kg
Previous
100 mg/kg
Method A industrial cleanup level;
enforcement by Ecology at its discretion
New
—
OU4, South Tacoma Field
129
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Contaminant
Media
ROD
Cleanup
Level
Standard*
Citation/Year
TPH-gas
Groundwater
1000ng/L
Previous
1000 ng/L
MTCA Method A
TPH-diesel
Groundwater
New
See citation
Revised 2001 MTCA calculations for
Method B are 500 (ig/L (non-
carcinogenic) for diesel and heavy oil by
NWTPH-Dx analyses. For gas range
organics, revised Method B concentration
is 800 ng/L (with benzene), 1000 (ig/L
(w/out benzene).
TPH-oil
Groundwater
1,1,2 - Tricholorethane
Groundwater
5 ng/L
Previous
5 ng/L
MCL
New
5 ng/L
MCL is unchanged. Calculated
concentration per 2001 MTCA Revised
Method B calculation is 0.768 (ig/L for
carcinogenic effects, and 320 (ig/L for
non-carcinogenic effects. Revised MTCA
allows use of MCL for this contaminant.
Naphthalene
Groundwater
32 ng/L
Previous
20 ng/L
MTCA Method A, 2001
New
160 ng/L
MTCA Method A, 2007
Benzene
Groundwater
5 f-ig/L
Previous
5 f-ig/L
MCL
New
5 f-ig/L
MCL unchanged. Concentration per
Revised Method A is 5(ig/L, and per
Revised Method B calculation is 0.8 (ig/L
for carcinogenic effects, 32 (ig/L for non-
carcinogenic effects. Revised MTCA
allows use of MCL for this contaminant/
Toluene
Groundwater
1000 ng/L
Previous
1600 ng/L
MCL; MTCA Method B, non
carcinogenic
New
640 ng/L
MCL unchanged; MTCA Method B, non
carcinogenic, 2001
Ethylbenzene
Groundwater
700 ng/L
Previous
700 ng/L
MCL
New
700 ng/L
MCL unchanged. Concentration per
Revised Method A is 700 ng/L, and per
Revised Method B calculation is 800 (ig/L
for non-carcinogenic effects
Xylene (total)
Groundwater
10000 ng/L
Previous
10000 ng/L
MCL
New
1600 ng/L
MCL unchanged; MTCA Method B, non
carcinogenic, 2007
Lead
Groundwater
NE**
Previous
15^g/L
MTCA Method A
New
—
Acetone
Groundwater
NE
Previous
800 ng/L
MTCA Method B, non carcinogenic
New
7200 ng/L
MTCA Method B, non carcinogenic, 2011
2-Butanone
Groundwater
NE
Previous
4800 ng/L
MTCA Method B, non carcinogenic,
New
—
n-Butylbenzene
Groundwater
NE
Previous
None
None
New
—
Sec-Butylbenzene
Groundwater
NE
Previous
None
None
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South Tacoma Channel Superfund Site Five-Year Review
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Contaminant
Media
ROD
Cleanup
Level
Standard*
Citation/Year
New
—
T ert-Buty lbenzene
Groundwater
NE
Previous
None
None
New
—
Carbon Tetrachloride
Groundwater
NE
Previous
0.34 (ig/L
MTCA Method B, carcinogenic
New
0.63 (ig/L
MTCA Method B, carcinogenic, 2011
1,2 - Dichlorobenzene
Groundwater
NE
Previous
600 (ig/L
MCL
New
—
1,3 - Dichlorobenzene
Groundwater
NE
Previous
None
None
New
—
1,4 - Dichlorobenzene
Groundwater
NE
Previous
1.8 f-ig/L
MTCA Method B non carcinogenic
New
Researched
- no data
MTCA Method B, non carcinogenic,
based on updated toxicity value, 2011
1,2 - Dichloroethane
Groundwater
NE
Previous
5 ng/L
MCL
New
0.481 (ig/L
MCL unchanged; Concentration per
revised Method A is 5 |ig/L, and per
revised Method B is 0.481 (ig/L for
carcinogenic effects and 160 \ig fL for
non-carcinogenic effects, 2001
n-Hexane
Groundwater
NE
Previous
480 (ig/L
MTCA Method B
New
—
Isopropy lbenzene
Groundwater
NE
Previous
None
None
New
—
p-I sopropy lbenzene
Groundwater
NE
Previous
None
None
New
—
n-propylbenzene
Groundwater
NE
Previous
None
None
New
—
1,2,3-
trichlorobenzene
Groundwater
NE
Previous
None
None
New
—
1,2,4-
trichlorobenzene
Groundwater
NE
Previous
70 f-ig/L
MCL
New
1.5ng/L
MCL unchanged. Calculated concen-
tration per Revised MTCA Method B is 80
(ig/L for non carcinogenic effects and 1.5
(ig/L for carcinogenic effects, 2001
1,3,5-
Trimethylbenzene
Groundwater
NE
Previous
400 (ig/L
MTCA Method B, non carcinogen
New
80 (ig/L
MTCA Method B, non carcinogen, 2011
1,2,4-
Trimethylbenzene
Groundwater
NE
Previous
400 (ig/L
MTCA Method B, non carcinogen
New
Researched
- no data
MTCA Method B, non carcinogen , based
on updated toxicity value, 2011
Anthracene
Groundwater
NE
Previous
4800 (ig/L
MTCA Method B for non-carcinogen
New
—
Benzo(g,h,i)perylene
Groundwater
NE
Previous
None
None
New
—
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131
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*Previous Standard is at time of the ROD. If 'NA', no standard was established at the time of the ROD. New Standard is the most
recent update post-ROD. If '—no updates have been made to the standard.
**NE - Not evaluated
OU 1, Well 12A
132
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Table 2-5. Changes in Action-Specific Requirements
Action
Requirement
Prerequisite
Citation/Year
Soil and
Groundwater
Previous
Industrial criteria used for capping
levels. Some groundwater cleanup
levels used MTCA levels.
Hazardous contaminants
regulated under MTCA
are present in groundwater
and soil at the site.
Washington State Model
Toxics Control Act (RCW
70.105D; WAC 173-340)
New
Updated in 2001 and 2007 - see
text for updates to standards
—
Washington State Model
Toxics Control Act (RCW
70.105D; WAC 173-340),
2001 and 2007 updates
Soil
Previous
Land Disposal Restrictions
provisions for placement of
hazardous hot spot soils left in
place. Closure requirements met by
conducting a hybrid-landfill
closure at site that includes cap
maintenance and groundwater
monitoring.
Contaminated media was
contained in place and
remains at the site.
Resource Conservation and
Recovery Act (RCRA, 49
CFR 261) Washington
State Dangerous Waste
Regulations (WAC
173303)
New
No changes that impact remedy
since last Five-Year Review
—
—
Soil
Previous
Soils with PCB concentrations
greater than 50 mg/kg destroyed by
incineration or disposed in
chemical waste landfill.
Soils are present at the site
that contain PCBs.
Toxic Substances Control
Act (TSCA 15 U.S.C 2601-
2671; 40 CRF Part 761.60)
New
No changes that impact remedy
since last Five-Year Review
—
—
Soil
Previous
Any soil removals should be
compliant with these requirements.
Soil removal is required at
the site.
Transportation of
Hazardous Materials (49
CFR, RCW 46.48, WAC
446-50)
New
No changes that impact remedy
since last Five-Year Review
—
—
Groundwater
Previous
Federal MCLs shall be met to
prevent exposure of the public to
contaminated drinking water.
Contaminated
groundwater is present at
the site with contaminants
regulated under federal
guidelines. Groundwater
is adjacent to drinking
water sources.
Section 1412 of the Safe
Drinking Water Act
(SDWA), 42 U.S.C. 300g-
1, "National Drinking
Water Regulations";
National Primary Drinking
Water Regulations. 40 CFR
Part 141
New
Exposure toxicity for TCE is
currently under revision.
—
—
Air
Previous
If groundwater treatment systems
produce air emissions - not
applicable to current remedy.
Original remedy
specificed in the ROD
required use of air
sparging for treatment of
groundwater.
Clean Air Act, 42 U.S.C.
7401), Washington State
Clean Air Act (RCW
70.94, WAC 173-400-460)
and Puget Sound Air
Pollution Control Authority
New
No changes that impact remedy
since last Five-Year Review
—
—
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133
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Table 2-6. Changes in Location-Specific Requirements
Location
Requirement
Prerequisite
Citation Year
Wetlands
Previous
Regulate actions that occur in
wetlands and floodplains. Remedial
actions in drainage channel are
limited to ICs and were not
anticipated to adversely impact
drainage channel.
Portions of the site
are either within or
adjacent to wetlands
and floodplain.
Clean Water Act (CWA)
Section 402)
Floodplain management
(Executive Order 11988)
and Protection of Wetlands
(Executive Order 11900)
New
The requirement has not been updated
or superseded. This is still applicable.
—
2.7.3. Question C: Has any other information come to light that could call into
question the protectiveness of the remedy?
No. No other information has come to light that could call into question the protectiveness of the remedy.
2.7.4. Technical Assessment Summary
The soil remedies are complete; hot spots have been removed and treated on-site and the remaining areas
of soil contamination have been removed, consolidated on-site, and capped. ICs are in place to protect
direct contact of workers with contaminated soils and to prevent groundwater at Pioneer Builders supply
from use as drinking water. Fencing has been installed around the northern and central portion of the site
and at the main entrance to restrict access. Operation and maintenance procedures are in place to ensure
cap and fencing integrity.
Groundwater monitoring is used to assess impacts of the soil-consolidation areas on local groundwater.
Concentrations of lead in two STF wells were above the the MTCA A action level over the last three
years (site specific lead concentration standards were not established in the ROD). A significant increase
was observed in December 2012, during a period of higher groundwater levels, and may indicate that
some contaminated soil in the vadose zone was exposed to continuous saturation that has not occurred in
the past, resulting in some particulate or soluble material migrating into the groundwater. The
groundwater monitoring program should be modified to determine if there is a continuing source of
contamination to groundwater. MNA at Pioneer Builders Supply has been slower than expected; however,
concentrations recently dropped below MTCA A action levels. Monitoring should continue to determine
if MNA is effective.
Several MTCA standards have changed since the remedy was selected. Washington Department of
Ecology modified MTCA substantially in 2001 and 2007. Revisions to soil cleanup levels were primarily
based on the protection of groundwater, so they do not likely impact the protectiveness of the remedy
with respect to industrial worker direct contact exposure but may impact protectiveness of groundwater.
Ongoing monitoring of groundwater will be conducted to confirm that groundwater concentrations
continue to meet current cleanup levels. There are no changes in exposure pathways at the site.
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South Tacoma Channel Superfund Site Five-Year Review
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2.8. Issues
Table 2-7 summarizes the current issues for the STF OU.
Table 2-7. Issues for the South Tacoma Field OU
Issues
Affects Current
Protectiveness
(Y/N)
Affects Future
Protectiveness
(Y/N)
1. Lead concentrations increased in two STF wells
N
Y
2. Wells STM-1A and NMW-8A are damaged and have not been
repaired.
N
Y
3. The effectiveness of MNA at Pioneer Building Supply has not been
evaluated as recommended in the previous FYR.
N
Y
2.9. Recommendations and Follow-up Actions
Table 2-8 provides recommendations to address the current issues at the STF OU, along with proposed
milestone dates to achieve the follow-up actions.
Table 2-8. Recommendations and Followup Actions
Issue
Recommendations and
Followup Actions
Party
Responsible
Oversight
Agency
Milestone
Date
Affects
Protectiveness (Y/N)
Current
Future
1.
Modify the groundwater
monitoring program to
determine if there is an ongoing
source to groundwater from the
contaminated soils.
BNSF
EPA
September
2014
N
Y
2.
Replace wells STM-1 A and
NMW-8A to ensure the
groundwater monitoring
programs are complete.
BNSF
EPA
September
2014
N
Y
3.
Continue groundwater
monitoring at Pioneer Builders
Supply and complete an
evaluation of MNA. If future
sampling shows an increase in
concentrations, similar to the
historical fluctuations, the
impact of potential residual soil
contamination on groundwater
concentrations should be
investigated. This could include
additional soil and groundwater
sampling and an evaluation of
groundwater flow variations on
contaminant concentrations.
BNSF
EPA
September
2014
N
Y
OU4, South Tacoma Field
135
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Additional recommendations to be considered that do not affect current or future protectiveness of the
remedy:
• Include field parameters in annual progress reports.
2.10. Protectiveness Statements
The remedy at the STF OU is currently protective of human health and the environment in the short term
because ICs are in place to prevent direct contact with soil and use of groundwater at Pioneer Builders
Supply as drinking water. However, in order for the remedy to be protective in the long term, the
groundwater monitoring program needs to be revised to determine if there is an ongoing source to
groundwater from the contaminated soils and to ensure protectiveness.
2.11. Next Review
The next FYR for the STF OU is required by September 2018, five years from the date of this review.
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South Tacoma Channel Superfund Site Five-Year Review
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[This page is intentionally left blank.]
OU 1, Well 12A
137
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South Tacoma Field Figures
138
South Tacoma Channel Superfund Site Five-Year Review
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LAxr r\
ICV/Sf
sre/iAcoav
zawt
msH/A/ercw
a i 2
UPPROXBWTE SCAi£ W LflLES
SOUTH TACOUA FIELD
TACOMA, WA
SITE LOCATION MAP
966124.16/P6SK001
Figure 2-1. South Tacoma Field Site Vicinity Map
OU4, South Tacoma Field
139
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Kennedy/Jenka Consultants
250 125 0 250 500 750
SCALE IWfCCT
SOUTH TACOMA FIELD
TACOMA, WA
SAMPLING UNIT DESIGNATIONS
AT THE STF SITE
966124.53/P9SK009
Figure 2-2. South Tacoma Field Site Sub-Area Map
OU 1, Weil 12A
140
-------
SOUTH TACOWA FIELD
TACOMA, WA
MAJOR HISTORICAL USES
OF THE STF SITE
9661 24.53/P9SK010
FIGURE 1-2
Kennedy/Jenks Consultants
SCALE IN f£CT
BASE ytf RffEfiOCE
WALKER 4 ASSOC 10-22-68
SugFAg^OEBgjS SAILING PL AM
rORSlTTS 4 HILL ENGINEERS. INC
RETEC REhCD I AT!QN TECHNOLOCIES. INC.
SOUTH TACOUA SWAJJP
FORMER
SOUTH
TACOMA
SWAMP
LEGEND
—STF-HPt SITE BOUNDARY
I TCL YARD ABC*
2. Gantry crane area
3 FUEL tank
4, SMEO
5. LANTERN SMEO
6 STOREHOUSE. BElTHOuSE
ROLLING MILL. STORAGE BLOC
7 FUEL CELLAR
8. @uPn pit
9 TRASH OUfc#9
10 STORACE YARD
11 RUBBISH T»ACK CORRIDOR
12 CONCRETE CASTING PLANT
13 SANDBLAST SHED
I* BLACKSMITH SK3P
*5. CONCRETE FLOOR
16. LANDING STRIP
17. TRASH Burning area
IB TRASH PIT (PAINT SHOP)
19. CAR CASTINCS PLATFORM
20 PAINT SHOP
2 I . CAR SHOP
li. AIRPORT SLDG
23 MADISON STREET
24. OPEN SHEO
25 DRY KILN
26. WASTE SOAKING VAT
27. U5T (OIL)
2ft PAINT SHOP
29. PAINT HOUSE
30 FREIGHT REPAIR SHED
31 FINISHED LUMBER SHED
31. WHEEL SHOP
33 GENERATOR HOUSE
34 UST (OIL)
33 PUfcfS
36 01P TANK
37 OROP PIT
IB. WOCOWQRXIMC SHOP
39. COACH SHOP
40 BOILER HOUSE
41. O'L tanks
42. paint shop
43. BRASS
44. MACHINE SHOP
43 SOLVENT SHED
46. BOiuER. tun tank, and
COPPER SHOP
47 SOUTH MACHINE SHOP
46. TRASH BURNER
49. BLACKSMITH SHOP
50. IRON 4 STEEL STORAGE
31 , TURNTABLE
32. COKE 4 COAL
S3 FORMER IRON FOUNDRY
54, RAILCAR CLEANOUT AREA
S3. QuRiCD DRUMS (REMOVED)
58. FORMER BRASS FOUNDRY Sl7£
GRIFFIN
•ME EL
Figure 2-3. South Tacoma Field Major Historical Uses
OU 1, Well 12A
141
-------
tea
SL
m
wisasmoomh*
mmmaeom>
SL
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mttm
mi MLmmeeemp
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»•*
B3L.
m
mm
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an
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.UL
a«e
m
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tj» warm
till WW*
it**.
m mivm
mmt
mart
BIISfR
war*
BMP PI
ajm_
BttfW
BWBf
iNS'F
war
WBf
-111
JUI
JM
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J4I
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JSJt
JJI.
:t*l
MM
ItH
J il
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J
J
Figure 2-4. Burlington Northern Ownership Tax Parcel Map at South Tacoma Field
OU 1, Well 12A
142
-------
LEGEND
m
GRID NOT SAMPLED DURING RI OR RA
GRID ABOVE CAPPING LEVELS; COVERED WITH AT LEAST 1 FOOT OF SOIL OR CAPPED
WITH ASPHALT; MAINTENANCE REQUIRED
GRID POTENTIALLY ABOVE CAPPING LEVELS; NOT REMEDIATED; SAFETY PRECAUTIONS
REQUIRED
DGCUWER
NO WARRANTY £ ASSOCIATED WTTH THE ACCURACY OF CHEMICAL DATA DEPICTED ON THIS MAP.
CHEMICAL CONCENTRATIONS COULD BE HIGHER OR LOWER THAN SHOKW, PEOPLE WHO HANDLE
SO»L AT THE SHE (LE, CONTRACTORS} SHOULD TAKE CONSERVATIVE PRECAUTIONS TO PROTECT
AGAINST EXPOSURE. CONTACT AM ENVIRONMENTAL PROFESSIONAL FOR ASSISTANCE
DRAINAGE CHANNEL
RAILROAD TRACKS
FENCE
BURIED GEOTEXTILE; IDENTIFIES
UMfT OF TREATED OR
CONTAM!NATED SUBSURFACE SOIL
CAPPING LEVELS
ARSENIC 200 rog/kq
LEAD 1,000 mg/kg
cPAHs (TOTAL) 20 mg/kg
PCBs (TOTAL) 10 mg/kg
NOTE:
V) NO SAMPLMG/REMEDWnClN CONDUCTED WITHIM STRUCTURES. BURUNGTDN WAY RIGHT
OF WAY. OR PAVED AREA5* EXCEPT AS NOTED-
K*rm«dy/J»nlc« Consultants
APPROXIMATE SCALE IN FEET
SOUTH TACOWA FIELD
TACOWA, WA
MAINTENANCE GRIDS
006015.OO/POSKOI7
Figure 2-5. South Tacoma Field Containment Areas
OU 1, Well 12A
143
-------
LEGEND
MNMA-&- came wwrofhMc weu. iocaiion
Kannody/Jenka Consultants
0 350
APPROXIMATE SCAIE IN F£F
SOUTH TACOWA FIELD
TACOMA. WA
MONITORING WELL LOCATIONS
956124,53/P9SKQ03
Figure 2-6. South Tacoma Field Monitoring Well Locations
OU 1, Well 12A
144
-------
LEGEND
NMW-1A-^- MONITORING WELL
¦ EXISTING RAILROAD TRACKS
X 11 X EXISTING FENCE
UNDERGROUND TANK EXCAVATION
NOTE:
1) ALL LOCATIONS ARE APPROXIMATE.
I
o
APPROXIMATE SCALE IN FEET
Kennedy/Jenks Consultants
SOUTH TACOMA FIELD
TACOMA, WA
PIONEER BUILDERS SUPPLY
MONITORING WELL LOCATIONS
966124.53/P9SK002
FIGURE 3-2
Figure 2-7. Monitoring Well Locations Pioneer Builders Supply
OU 1, Well 12A
145
-------
o
'+¦»
ai
u
o o
U i
0
Jan-98 Jan-00 Jan-02
¦TPH-Gas (mg/L)- CUL=0.5
¦Benzene (ug/L)- CUL=5
TPH-Diesel (mg/L)- CUL=0.8
¦Depth to Water
40
35
30
25
20 |
15
10
5
0
Jan-10 Jan-12 Jan-14
Figure 2-8. Concentrations of TPH as gas, TPH as diesel, and benzene at NMW-1A
146
South Tacoma Channel Superfund Site Five-Year Review
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Appendix 2-A: South Tacoma Field List of
Documents Reviewed
148
South Tacoma Channel Superfund Site Five-Year Review
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OU4, South Tacoma Field 149
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List of Documents Reviewed, South Tacoma Field
Kennedy Jenks Consultants. Remedial Action Report, South Tacoma Field Site, March, 2000.
Kennedy Jenks Consultants. Site Development and Institutional Controls Plan for South Tacoma Field
Site, Tacoma, Washington. March 2000.
Kennedy Jenks Consultants. Operations and Maintenance Plan for South Tacoma Field Site, Tacoma,
Washington. March 2000.
Kennedy Jenks Consultants. South Tacoma Field 2008 Annual Progress Report. March 2009.
Kennedy Jenks Consultants. South Tacoma Field 2009 Annual Progress Report. April 2010.
Kennedy Jenks Consultants. South Tacoma Field 2010 Annual Progress Report. April 2011.
Kennedy Jenks Consultants. South Tacoma Field 2011 Annual Progress Report. May 2012.
Kennedy Jenks Consultants. South Tacoma Field 2012 Annual Progress Report. March 2013.
US EPA, Region 10. Record of Decision for Commencement Bay South Tacoma Channel, South
Tacoma Field Operable Unit. September 1994.
US EPA, Region 10. Explanation of Significant Differences for South Tacoma Field Record of
Decision, Commencement Bay, South Tacoma Channel Superfund Site. August 1999.
US EPA, Region 10. First Five-Year Review Report for South Tacoma Field, Tacoma, Washington.
June 2003.
US EPA, Region 10. Second Five-Year Review Report for South Tacoma Field, Tacoma, Washington.
September 2008.
US EPA, Region 10. Final Closeout Report for Soils, Commencement Bay, South Tacoma Channel
Superfund Site, South Tacoma Field Operable Unit. February 2005.
150
South Tacoma Channel Superfund Site Five-Year Review
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Appendix 2-B: South Tacoma Field Site
Inspection Photographs
152
South Tacoma Channel Superfund Site Five-Year Review
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South Tacoma Field Site Visit Photographs
Photo 1. Southern consolidation area
Photo 2. South end of site looking toward Taylor Street
154
South Tacoma Channel Superfund Site Five-Year Review
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Photo 3. Rail car at south end of site.
Photo 4. Northern consolidation area
OU4, South Tacoma Field
155
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jaasMl
Photo 5. Grid-area marker at southern portion of site
Photo 6. Fencing along east side of site
156
South Tacoma Channel Superfund Site Five-Year Review
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Photo 7. Gate access at Burlington Way with 'No Trespassing' sign
Photo 7. Ecology blocks at south end of site
OU4, South Tacoma Field
157
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Photo 8. Illegal dumping along Burlington Way
Photo 9. Damaged well STF-01.
158
South Tacoma Channel Superfund Site Five-Year Review
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OU 1, Well 12A
159
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Appendix 2-C: South Tacoma Field Site
Inspection Checklist
160
South Tacoma Channel Superfund Site Five-Year Review
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Five-Year Review Site Inspection Checklist
I. SITE INFORMATION
Site name: South Tacoma Field
Date of inspection: 5 MARCH 2013
Location: Tacoma, WA
EPA ID: WAD980726301
Agency, office, or company leading the five-year
review: BNSF Railroad and Kennedy Jenks
Consultants
Weather/temperature: Overcast, mid 50s
Remedy Includes: (Check all that apply)
~ Landfill cover/containment
£3 Access controls
^Institutional controls
~ Groundwater pump and treatment
~ Surface water collection and treatment
Other: Groundwater monitoring; soil excavation and containment
£3 Monitored natural attenuation
~ Groundwater containment
~ Vertical barrier walls
Attachments: ~ Inspection team roster attached
~ Site map attached
II. INTERVIEWS (Check all that apply)
1. O&M site manager
Bruce Sheppard Enviro Remediation Mng. 5 MAR 2013_
Name Title Date
Interviewed at site ~ at office ~ by phone Phone no.
Problems, suggestions; ^ Report attached
2. O&M staff
Dean Malte
Name
Interviewed IS] at site Dat office ~ by phone Phone no.
Problems, suggestions; ^ Report attached
Senior Geologist_
Title
_5 MAR 2013_
Date
162
South Tacoma Channel Superfund Site Five-Year Review
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3. Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency response
office, police department, office of public health or environmental health, zoning office, recorder of
deeds, or other city and county offices, etc.) Fill in all that apply.
Agency:
Contact:
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
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4.
Other interviews (optional) ^ Report attached.
Nathan Graves, Project Manager for Kennedy Jenks Consultants, Consultant to BNSF Railroad. Interviewed on
13 March 2013 via phone.
III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)
O&M Documents
ISI O&M manual
ISI As-built drawings
El Maintenance logs
Remarks
£3 Readily available
£3 Readily available
£3 Readily available
£3 Up to date ~ N/A
£3 Up to date ~ N/A
£3 Up to date ~ N/A
Site-Specific Health and Safety Plan ~ Readily available ~ Up to date £3 N/A
~ Contingency plan/emergency response plan ~ Readily available ~ Up to date £3 N/A
Remarks
O&M and OSHA Training Records
Remarks
~ Readily available ~ Up to date ^N/A
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South Tacoma Channel Superfund Site Five-Year Review
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4. Permits and Service Agreements
~ Air discharge permit ~ Readily available ~ Up to date £3 N/A
~ Effluent discharge ~ Readily available QUp to date £3 N/A
~ Waste disposal, POTW ~ Readily available ~ Up to date ~ N/A
~ Other permits ~ Readily available ~ Up to date ^ N/A
Remarks
5. Gas Generation Records ~ Readily available ~ Up to date £3 N/A
Remarks
6. Settlement Monument Records ~ Readily available ~ Up to date ^ N/A
Remarks
7. Groundwater Monitoring Records
Remarks
£3 Readily available £3 Up to date DN/A
Leachate Extraction Records
Remarks
~ Readily available ~ Up to date ^ N/A
9. Discharge Compliance Records
~ Air
~ Water (effluent)
Remarks
~ Readily available ~ Up to date N/A
~ Readily available ~ Up to date N/A
10. Daily Access/Security Logs
Remarks
~Readily available ~ Up to date ^ N/A
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IV. O&M COSTS
1.
O&M Organization
~ State in-house
~ Contractor for State
~ PRP in-house
Contractor for PRP
~Federal Facility in-house
~ Contractor for Federal Facility
~ Other
2.
O&M Cost Records
~ Readily available
~ Up to date
~ Funding mechanism/agreement
in place
Original O&M cost estimate
~ Breakdown attached
Total annual cost by year for review period if available
From To
~Breakdown attached
Date
Date
Total cost
From To
~ Breakdown attached
Date
Date
Total cost
From To
~ Breakdown attached
Date
Date
Total cost
From To
~ Breakdown attached
Date
Date
Total cost
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South Tacoma Channel Superfund Site Five-Year Review
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3. Unanticipated or Unusually High O&M Costs During Review Period
Describe costs and reasons:
V. ACCESS AND INSTITUTIONAL CONTROLS M Applicable ~ N/A
A. Fencing
1. Fencing damaged ~ Location shown on site map ^Gates secured ~ N/A
Remarks New fencing recently installed .
B. Other Access Restrictions
1. Signs and other security measures ~ Location shown on site map ~ N/A
Remarks
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C. Institutional Controls (ICs)
1. Implementation and enforcement
Site conditions imply ICs not properly implemented ~ Yes ^ No ~ N/A
Site conditions imply ICs not being fully enforced ~ Yes £3 No ~ N/A
Type of monitoring (e.g., self-reporting, drive by) _physical inspection at site_
Frequency annually
Responsible party/agency Kennedy Jenks Consultants_
Contact Dean Malte Senior Geologist 253-835-6463
Name Title Date Phone no.
Reporting is up-to-date ^ Yes ~ No ~ N/A
Reports are verified by the lead agency ^ Yes ~ No ~ N/A
Specific requirements in deed or decision documents have been met ^ Yes ~ No ~ N/A
Violations have been reported ^ Yes ~ No ~ N/A
Other problems or suggestions: Report attached
2. Adequacy ICs are adequate ~ ICs are inadequate ~ N/A
Remarks
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South Tacoma Channel Superfund Site Five-Year Review
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D. General
1. Vandalism/trespassing ~ Location shown on site map No vandalism evident
Remarks
2. Land use changes on site ^ N/A
Remarks
3. Land use changes off site ~ N/A
Remarks Land adjacent to the site recently acquired by Sound Transit
VI. GENERAL SITE CONDITIONS
A. Roads ~ Applicable £3 N/A
1. Roads damaged ~ Location shown on site map ~ Roads adequate ~ N/A
Remarks
B. Other Site Conditions
Remarks
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VII. LANDFILL COVERS ~ Applicable M N/A
A. Landfill Surface
1. Settlement (Low spots)
Areal extent
Remarks
Cracks
Lengths_
Remarks
~ Location shown on site map ~ Settlement not evident
Depth
~ Location shown on site map ~ Cracking not evident
Widths Depths
Erosion
Areal extent_
Remarks
~ Location shown on site map ~ Erosion not evident
Depth
Holes
Areal extent_
Remarks
~ Location shown on site map ~ Holes not evident
Depth
Vegetative Cover ~ Grass QCover properly established ~ No signs of stress
~ Trees/Shrubs (indicate size and locations on a diagram)
Remarks
Alternative Cover (armored rock, concrete, etc.) ~ N/A
Remarks
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South Tacoma Channel Superfund Site Five-Year Review
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7. Bulges
Areal extent_
Remarks
~ Location shown on site map ~ Bulges not evident
Height
Wet Areas/Water Damage
~ Wet areas
~ Ponding
~ Seeps
~ Soft subgrade
Remarks
~ Wet areas/water damage not evident
~ Location shown on site map Areal extent_
~ Location shown on site map Areal extent_
~ Location shown on site map Areal extent_
~Location shown on site map Areal extent_
9. Slope Instability ~ Slides
Areal extent
Remarks
~ Location shown on site map ~ No evidence of slope instability
B. Benches
~ Applicable N/A
(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope
in order to slow down the velocity of surface runoff and intercept and convey the runoff to a lined
channel.)
1. Flows Bypass Bench
Remarks
~ Location shown on site map
~ N/A or okay
2. Bench Breached
Remarks
~ Location shown on site map
~ N/A or okay
3. Bench Overtopped
Remarks
~ Location shown on site map
~ N/A or okay
OU4, South Tacoma Field
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C. Letdown Channels ~ Applicable ^ N/A
(Channel lined with erosion control mats, riprap, grout bags, or gabions that descend down the steep side
slope of the cover and will allow the runoff water collected by the benches to move off of the landfill
cover without creating erosion gullies.)
1. Settlement
Areal extent_
Remarks
~ Location shown on site map ~ No evidence of settlement
Depth
2. Material Degradation ~ Location shown on site map QNo evidence of degradation
Material type Areal extent
Remarks
Erosion
Areal extent_
Remarks
~ Location shown on site map ~ No evidence of erosion
Depth
Undercutting
Areal extent
Remarks
~ Location shown on site map ~ No evidence of undercutting
Depth
Obstructions Type
~ Location shown on site map
Size
Remarks
_ ~ No obstructions
Areal extent
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South Tacoma Channel Superfund Site Five-Year Review
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6. Excessive Vegetative Growth Type
~ No evidence of excessive growth
~ Vegetation in channels does not obstruct flow
~ Location shown on site map Areal extent
Remarks
D. Cover Penetrations ~ Applicable £3 N/A
1. Gas Vents ~ Active ~ Passive
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance
~ N/A
Remarks
2. Gas Monitoring Probes
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks
3. Monitoring Wells (within surface area of landfill)
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks
4. Leachate Extraction Wells
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks
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5. Settlement Monuments ~ Located ~ Routinely surveyed DN/A
Remarks
E. Gas Collection and Treatment ~ Applicable ^N/A
1. Gas Treatment Facilities
~ Flaring ~ Thermal destruction ~ Collection for reuse
~ Good condition ~ Needs Maintenance
Remarks
2. Gas Collection Wells, Manifolds and Piping
~ Good condition ~ Needs Maintenance
Remarks
3. Gas Monitoring Facilities {e.g., gas monitoring of adjacent homes or buildings)
~ Good condition ~ Needs Maintenance ~ N/A
Remarks
F. Cover Drainage Layer ~ Applicable N/A
1. Outlet Pipes Inspected ~ Functioning ~ N/A
Remarks
2. Outlet Rock Inspected ~ Functioning ~ N/A
Remarks
G. Detention/Sedimentation Ponds ~ Applicable N/A
174
South Tacoma Channel Superfund Site Five-Year Review
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1. Siltation Areal extent Depth ~ N/A
~ Siltation not evident
Remarks
2. Erosion Areal extent Depth
~ Erosion not evident
Remarks
3. Outlet Works ~ Functioning ~ N/A
Remarks
4. Dam ~ Functioning ~ N/A
Remarks
H. Retaining Walls ~ Applicable ^ N/A
I. Deformations ~ Location shown on site map ~ Deformation not evident
Horizontal displacement Vertical displacement
Rotational displacement
Remarks
2. Degradation ~ Location shown on site map ~ Degradation not evident
Remarks
I. Perimeter Ditches/Off-Site Discharge ~ Applicable N/A
1. Siltation ~ Location shown on site mapD Siltation not evident
Areal extent Depth
Remarks
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Vegetative Growth ~ Location shown on site map
~ Vegetation does not impede flow
Areal extent Type
Remarks
~ N/A
Erosion
Areal extent_
Remarks
~ Location shown on site map ~ Erosion not evident
Depth
Discharge Structure ~ Functioning ~ N/A
Remarks
VIII. VERTICAL BARRIER WALLS ~ Applicable |g| N/A
Settlement
Areal extent_
Remarks
~ Location shown on site map ~ Settlement not evident
Depth
2. Performance MonitoringType of monitoring_
~ Performance not monitored
Frequency
Evidence of breaching
Head differential
Remarks
IX. GROUNDWATER/SURFACE WATER REMEDIES M Applicable ~ N/A
A. Groundwater Extraction Wells, Pumps, and Pipelines
~ Applicable £3 N/A
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South Tacoma Channel Superfund Site Five-Year Review
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1. Pumps, Wellhead Plumbing, and Electrical
~ Good condition ~ All required wells properly operating ~ Needs Maintenance ~ N/A
Remarks
2. Extraction System Pipelines, Valves, Valve Boxes, and Other Appurtenances
~ Good condition ~ Needs Maintenance
Remarks
3. Spare Parts and Equipment
~ Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks
B. Surface Water Collection Structures, Pumps, and Pipelines ~ Applicable £3 N/A
1. Collection Structures, Pumps, and Electrical
~ Good condition ~ Needs Maintenance
Remarks
2. Surface Water Collection System Pipelines, Valves, Valve Boxes, and Other Appurtenances
~ Good condition ~ Needs Maintenance
Remarks
3. Spare Parts and Equipment
~ Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks
C. Treatment System ~ Applicable N/A
OU4, South Tacoma Field
177
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1.
Treatment Train (Check components that apply)
~ Metals removal ~ Oil/water separation ~ Bioremediation
~ Air stripping ~ Carbon adsorbers
~ Filters
~ Additive (e.£., chelation agent, flocculent)
~ Others
~ Good condition ~ Needs Maintenance
~ Sampling ports properly marked and functional
~ Sampling/maintenance log displayed and up to date
~ Equipment properly identified
~ Quantity of groundwater treated annually
~ Quantity of surface water treated annually
Remarks
2.
Electrical Enclosures and Panels (properly rated and functional)
~N/A ~ Good condition ~ Needs Maintenance
Remarks
3.
Tanks, Vaults, Storage Vessels
~N/A ~ Good condition ~ Proper secondary containment ~ Needs Maintenance
Remarks
4.
Discharge Structure and Appurtenances
~ N/A ~ Good condition ~ Needs Maintenance
Remarks
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South Tacoma Channel Superfund Site Five-Year Review
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5.
Treatment Building(s)
~ N/A ~ Good condition (esp. roof and doorways) ~ Needs repair
~ Chemicals and equipment properly stored
Remarks
6.
Monitoring Wells (pump and treatment remedy)
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~Good condition
~ All required wells located ~ Needs Maintenance ~ N/A
Remarks
D. Monitoring Data
3.
Monitoring Data
~ Is routinely submitted on time O Is of acceptable quality
4.
Monitoring data suggests:
£3 Groundwater plume is effectively contained ~ Contaminant concentrations are declining
D. Monitored Natural Attenuation
1.
Monitoring Wells (natural attenuation remedy)
£3 Properly secured/locked Functioning ^ Routinely sampled Good condition
E3A11 required wells located ^Needs Maintenance ON/A
Remarks Some wells are damaged and need to be decommissioned or replaced.
X. OTHER REMEDIES
If there are remedies applied at the site which are not covered above, attach an inspection sheet describing
the physical nature and condition of any facility associated with the remedy. An example would be soil
vapor extraction.
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XL OVERALL OBSERVATIONS
A.
Implementation of the Remedy
Describe issues and observations relating to whether the remedy is effective and functioning as designed.
Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume,
minimize infiltration and gas emission, etc.).
The remedy is generally functioning as intended. There is the possibility for remaining soil
contamination at Pioneer Builders supply that may be contributing groundwater contamination and
requires characterization.
B.
Adequacy of O&M
Describe issues and observations related to the implementation and scope of O&M procedures. In
particular, discuss their relationship to the current and long-term protectiveness of the remedy.
O&M effort has been optimized base on the need to only do annual sampling. Historical problem with
trespassing and illegal dumping has been remediated with the installation of new fences and gates.
180
South Tacoma Channel Superfund Site Five-Year Review
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C. Early Indicators of Potential Remedy Problems
Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high
frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be
compromised in the future.
None
D. Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
None
OU4, South Tacoma Field
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Appendix 2-D: South Tacoma Field Interview
Transcripts
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South Tacoma Channel Superfund Site Five-Year Review
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South Tacoma Field Interview Transcripts
Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Date:
Interview Method:
Interview Contacts:
South Tacoma Field, South Tacoma Channel Superfund Site
WAD980726301
Bruce Sheppard
5 March 2013
In person at Site Visit
Kristen Kerns USACE Seattle, Kristen.kerns@usace.army.mil
Interview Questions (responses are paraphrased)
1. What is your current role as it relates to the site? How long have you been aware of or
associated with the site?
Bruce Sheppard oversees environmental restoration and remediation for BNSF. He is the
primary representative for the PRP for this site.
2. What is your overall impression of the work conducted at the site to date?
Work at site is going well. No major issues recently.
3. Have there been routine communications or activities (site visits, inspections, reporting
activities, etc.) conducted by your office regarding the site? (If so, please give purpose and
results.)
BNSF has contracted with Kennedy Jenks Consultants to conduct site inspection and
monitoring. Results of inspection/monitoring are reported to BNSF annually.
4. Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
No
Follow on Question: If there is no continuous on-site presence, describe staff and frequency
of site inspections and activities (e.g. what types of monitoring activities occur at what
frequencies).
Kennedy Jenks Consultants performs annual inspection/monitoring. Tacoma water has catch
basins and infrastructure on site that they might periodically check. City of Tacoma likely
patrols adjacent to the site due to previous trespassing issues.
5. Would you say that O&M and/or sampling efforts have been optimized? Are there portions
of the remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
O&M sampling efforts are going well. No specific comment regarding possible optimization.
184
South Tacoma Channel Superfund Site Five-Year Review
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6. What is the current status of construction? Have any problems or difficulties been
encountered that have impacted construction progress or implementability?
Complete
• Are there any other significant construction activities proposed?
NA
7. What does the monitoring data show?
• Are there any trends in the data that show contaminant levels are increasing or
decreasing?
Data shows possible natural attenuation occurring at Pioneer Builder Site.
• Have any new or emerging COCs been identified?
No
8. Have there been unexpected O&M difficulties or costs at the site in the last five years? If so,
please give details.
There have been difficulties with trespassing at the site, including illegal dumping. Cleanup of
dumping resulted in significant costs for regular removal of trash. Installation of fencing
around the site in 2011 greatly improved issues related to trespassing.
9. Are you aware of any institutional controls, site access controls, new ordinances in place,
changes in actual or projected land use, complaints being filed or unusual activities at the
site? If so, please describe in detail.
No
10. Are you aware of any ongoing community concerns regarding the site or its administration?
No community concerns. Community is interested in seeing the site developed.
11. Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
Trespassing, illegal dumping, transient use, and meth labs. All incidents have been
remediated with installation of fencing. City of Tacoma helped clear out meth labs.
12. Have any problems been encountered which required, or will require changes to this
remedial design or ROD?
No
OU4, South Tacoma Field
185
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13. Do you have any comments, suggestions, or recommendations regarding the site's
management, operation, or any other aspects of the site?
No
186
South Tacoma Channel Superfund Site Five-Year Review
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Five Year Review Interview Record
Site Name:
EPA ID No.
Interviewee:
Date:
South Tacoma Field, South Tacoma Channel Superfund Site
WAD980726301
Dean Malte
5 March 2013
Interview Method: In person at Site Visit
Interview Contacts: Kristen Kerns USACE Seattle, Kristen.kerns@usace.army.mil
Interview Questions (responses from interviewee are paraphrased)
1. What is your current role as it relates to the site? How long have you been aware of or
associated with the site?
Kennedy Jenks Consultants is a contractor to BNSF designated for inspection and monitoring
of the South Tacoma Field Site. Dean's role is the primary site inspector and conducting
monitoring annually at the site.
2. What is your overall impression of the work conducted at the site to date?
Work has been routine and generally running smoothly. Installation of gates has improved
access and inhibited trespassing.
3. Have there been routine communications or activities (site visits, inspections, reporting
activities, etc.) conducted by your office regarding the site? (If so, please give purpose and
Dean has been responsible for conducting annual site inspections and monitoring at the site.
Purpose is to comply with O&M requirements. With the exception of some damaged well
heads, monitoring has been routine and results of monitoring have not produced any
significantly unexpected results.
4. Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
No continuous on site presence.
Follow on Question: If there is no continuous on-site presence, describe staff and frequency
of site inspections and activities (e.g. what types of monitoring activities occur at what
frequencies).
Dean is the primary site inspector and is on site once per year in the December/January time
frame.
5. Would you say that O&M and/or sampling efforts have been optimized? Are there portions
of the remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
Deferred specifics regarding optimization to Nathan Graves, colleague at Kennedy Jenks
Consultants.
results.)
OU4, South Tacoma Field
187
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6. What is the current status of construction? Have any problems or difficulties been
encountered that have impacted construction progress or implementability?
Construction is complete.
• Are there any other significant construction activities proposed?
No construction activities proposed in the near future.
7. What does the monitoring data show?
• Are there any trends in the data that show contaminant levels are increasing or
decreasing?
No surprising trends in the data. Some traces of lead at STF and Amsted wells.
• Have any new or emerging COCs been identified?
No new contaminants have emerged.
8. Have there been unexpected O&M difficulties or costs at the site in the last five years? If so,
please give details.
Damage to monitoring well inhibited traditional sampling but still able to collect using
modified method because of shallow water level. Prior difficulties with transients and
unknown site access conditions prior to installation of fencing in 2011.
9. Are you aware of any institutional controls, site access controls, new ordinances in place,
changes in actual or projected land use, complaints being filed or unusual activities at the
site? If so, please describe in detail.
None.
10. Are you aware of any ongoing community concerns regarding the site or its administration?
Community is not very vocal regarding the site.
11. Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
Significant trespassing issues prior to installing fence around site. Transient use and illegal
dumping was a major concern. Meth labs were also present on the western portion of the
site but have cleaned up by the City of Tacoma and have not been an issue recently.
12. Have any problems been encountered which required, or will require changes to this
remedial design or ROD?
None.
188
South Tacoma Channel Superfund Site Five-Year Review
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13. Do you have any comments, suggestions, or recommendations regarding the site's
management, operation, or any other aspects of the site?
None
OU4, South Tacoma Field
189
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Five Year Review Interview Record
Site Name: South Tacoma Field, South Tacoma Channel Superfund Site
EPA ID No. WAD980726301
Interviewee: Nathan Graves
Date: 13 March 2013
Interview Method: Phone
Interview Contacts: Kristen Kerns USACE Seattle, Kristen.kerns@usace.army.mil
Interview Questions (responses from interviewee are paraphrased)
1. What is your current role as it relates to the site? How long have you been aware of or
associated with the site?
Nathan is the project manager from Kennedy Jenks Consultants, a contractor to BNSF.
Nathan has been involved with the project since 1987. He wrote the Rl and FS report. Prior to
the RI/FS Nathan worked with other parties, primarily related to Amstead, regarding
contamination at the site.
2. What is your overall impression of the work conducted at the site to date?
The FS went relatively well and faster than expected. Issues that were encountered along the
way were typically resolved quickly. A UST containing petroleum products was discovered
during remedial design and transferred over to Department of Ecology. A No Further Action
notice is expected sometime shortly for the site.
3. Have there been routine communications or activities (site visits, inspections, reporting
activities, etc.) conducted by your office regarding the site? (If so, please give purpose and
results.)
Inspection and monitoring is performed once per year. There are sometimes other
infrequent visits to the site (related to UST, well replacement, etc).
4. Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
No
Follow on Question: If there is no continuous on-site presence, describe staff and frequency
of site inspections and activities (e.g. what types of monitoring activities occur at what
frequencies).
Kennedy Jenks Consultants staff are on site once per year to perform site inspection and
groundwater sampling.
5. Would you say that O&M and/or sampling efforts have been optimized? Are there portions
of the remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
190
South Tacoma Channel Superfund Site Five-Year Review
-------
Yes, the O&M effort has been optimized based on the need to only do annual sampling.
Historical problem with trespassing and illegal dumping has been remediated with the
installation of new fences and gates.
6. What is the current status of construction? Have any problems or difficulties been
encountered that have impacted construction progress or implementability?
Construction of the remedy is complete. There are plans to close out wells and replace a
damaged well at the site in 2013.
• Are there any other significant construction activities proposed?
No
7. What does the monitoring data show?
Groundwater levels have increased over the last several years. This has resulted in increased
saturation of the vadose zone. This is most notable at the north consolidation area and the
southern portion of the site. This does not appear to have an impact at the Amsted site. Lead
has also increase over time at the STF wells. Pioneer Builders concentrations have fluctuated
over time. Most recent sampling shows all concentrations are below cleanup levels at
Amsted.
• Are there any trends in the data that show contaminant levels are increasing or
decreasing?
See response above
• Have any new or emerging COCs been identified?
No
8. Have there been unexpected O&M difficulties or costs at the site in the last five years? If so,
please give details.
No significant difficulties. Some additional maintenance needed to install gates and fencing.
Some maintenance activities required prior to the previous five year review to fill areas of
standing water in maintenance grids.
9. Are you aware of any institutional controls, site access controls, new ordinances in place,
changes in actual or projected land use, complaints being filed or unusual activities at the
site? If so, please describe in detail.
None
10. Are you aware of any ongoing community concerns regarding the site or its administration?
None
OU4, South Tacoma Field
191
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11. Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
Vandalism and trespassing. Much of this was remediated with installation of new gates and
fencing.
12. Have any problems been encountered which required, or will require changes to this
remedial design or ROD?
No
13. Do you have any comments, suggestions, or recommendations regarding the site's
management, operation, or any other aspects of the site?
192
South Tacoma Channel Superfund Site Five-Year Review
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OU4, South Tacoma Field 193
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Appendix 2-E: South Tacoma Field Data
Summary
194
South Tacoma Channel Superfund Site Five-Year Review
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OU4, South Tacoma Field 195
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South Tacoma Field Data Summary
South Tacoma Field Groundwater Monitoring Data
Well
Date
PAHs (Mg/L)
Total Lead (|jg/L)
TPH as Diesel (mg/L)
TPH as Oil (mg/L)
Cleanup Level
NA
15
0.5
0.5
Amsted Wells
MW-1A
Jan-09
ND
<1
<0.240
<0.481
MW-1A
Jan-10
ND
<2.0
<0.12
<0.24
MW-1A
Dec-10
ND
0.45
<0.078
<0.39
MW-1A
Jan-12
ND
0.35
<0.075
<0.38
MW-1A
Dec-12
ND
<1.0
0.33
<0.250
CBS-4A
Jan-09
ND
<1.0
<0.238
<0.476
CBS-4A
Jan-10
ND
<2.0
<0.12
<0.24
CBS-4A
Dec-10
ND
<0.10
<0.076
<0.38
CBS-4A
Jan-12
ND
<0.10
<0.76
<0.38
CBS-4A
Dec-12
ND
<1.0
0.34
<0.250
VMW-1
Jan-09
ND
<1.0
<0.238
<0.476
VMW-1
Jan-10
ND
<2.0
<0.12
<0.24
VMW-1
Dec-10
ND
2.7
<0.079
<0.40
VMW-1
Jan-12
ND
0.44
<0.77
<0.38
VMW-1
Dec-12
ND
3.2
0.32
<0.250
STF Wells
STM-1A
Jan-09
NA
NA
NA
NA
STM-1A
Jan-10
NA
NA
NA
NA
STM-1A
Dec-10
NA
NA
NA
NA
STM-1A
Jan-12
NA
NA
NA
NA
STM-1A
Dec-12
NA
NA
NA
NA
STM-3A
Jan-09
NA
<1.0
NA
NA
STM-3A
Jan-10
NA
8.9
NA
NA
STM-3A
Dec-10
NA
19.9
NA
NA
STM-3A
Jan-12
NA
16.3
NA
NA
STM-3A
Dec-12
NA
130
NA
NA
STM-4A/M W-100
Jan-09
NA
13.2/2.71
NA
NA
STM-4A/MW-100
Jan-10
NA
15.0/19.0
NA
NA
STM-4A/MW-100
Dec-10
NA
50.4/45.6
NA
NA
STM-4A/MW-100
Jan-12
NA
74.5/70.8
NA
NA
STM-4A/MW-100
Dec-12
NA
260/290
NA
NA
CBS-7A
Jan-09
NA
2.03
NA
NA
CBS-7A
Jan-10
NA
9.8
NA
NA
CBS-7A
Dec-10
NA
0.92
NA
NA
CBS-7A
Jan-12
NA
0.69
NA
NA
CBS-7A
Dec-12
NA
<1.0
NA
NA
CBS-10A
Jan-09
NA
<1.0
NA
NA
CBS-10A
Jan-10
NA
<2.0
NA
NA
CBS-10A
Dec-10
NA
0.76
NA
NA
CBS-10A
Jan-12
NA
0.61
NA
NA
CBS-10A
Dec-12
NA
<1.0
NA
NA
VMW-2
Jan-09
NA
15.9
NA
NA
VMW-2
Jan-10
NA
<2.0
NA
NA
VMW-2
Dec-10
NA
3.2
NA
NA
VMW-2
Jan-12
NA
6.3
NA
NA
VMW-2
Dec-12
NA
<1.0
NA
NA
VMW-3
Jan-09
NA
<1.0
NA
NA
VMW-3
Jan-10
NA
<2.0
NA
NA
VMW-3
Dec-10
NA
1.4
NA
NA
VMW-3
Jan-12
NA
14.4
NA
NA
VMW-3
Dec-12
NA
<1.0
NA
NA
NMW-17A1
Jan-09
NA
<1.0
NA
NA
NMW-17A1
Jan-10
NA
<2.0
NA
NA
NMW-17A1
Dec-10
NA
<0.10
NA
NA
NMW-17A1
Jan-12
NA
<0.10
NA
NA
NMW-17A1
Dec-12
NA
<1.0
NA
NA
Notes:
Bold and highlight indicates concentration exceeds cleanup level
< - analyte not detected at the indicated laboratory reporting limit
OU 1, Well 12A
196
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OU4, South Tacoma Field 197
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Pioneer Builders Supply Groundwater Monitoring Data for TPH
Well
Date
TPH as
gasoline
(mg/L)
TPH as diesel
(mg/L)
TPH as oil
(mg/L)
Cleanup Level
0.8
0.5
0.5
NMW-1A/NMW-102
Jan-09
0.475/0.469
<0.243/<0.245
<0.485/0.490
NMW-1A/NMW-102
Jan-10
1.8/1.8
0.66/0.68
<0.24/0.24
NMW-1A/NMW-102
Dec-10
3.14/3.19
0.16/0.16
<0.38/0.38
NMW-1A/NMW-102
Jan-12
1.20/1.25
<0.077/<0.076
<0.38/0.38
NMW-1A/NMW-102
Dec-12
0.26/0.22
<0.10/<0.10
<0.25/0.25
NMW-8A
Jan-09
<0.500
<0.250
<0.500
NMW-8A
Jan-10
<0.050
<0.12
<0.24
NMW-8A
Dec-10
<0.50
<0.77
<0.38
NMW-8A
Jan-12
<0.50
<0.77
<0.38
NMW-8A
Dec-12
<0.10
<0.13
<0.33
NMW-9A
Jan-09
<0.500
<0.250
<0.500
NMW-9A
Jan-10
<0.050
<0.12
<0.24
NMW-9A
Dec-10
<0.050
<0.082
<0.41
NMW-9A
Jan-12
<0.50
<0.75
<0.38
NMW-9A
Dec-12
<0.10
<0.10
<0.25
NMW-10A
Jan-09
<0.500
<0.243
<0.485
NMW-10A
Jan-10
0.63
0.029
<0.24
NMW-10A
Dec-10
0.407
<0.078
<0.39
NMW-10A
Jan-12
<0.50
<0.77
<0.38
NMW-10A
Dec-12
0.58
<0.10
<0.25
NMW-11A
Jan-09
<0.500
<0.250
<0.500
NMW-11A
Jan-10
<0.050
<0.12
<0.25
NMW-11A
Dec-10
<0.050
<0.082
<0.41
NMW-11A
Jan-12
<0.50
<0.75
<0.38
NMW-11A
Dec-12
<0.10
<0.10
<0.25
Notes:
Bold and highlighted indicates concentration above the cleanup level
< - analyte not detected at the indicated laboratory reporting limit
OU 1, Well 12A
198
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OU4, South Tacoma Field 199
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3ioneer Builders Supply Groundwater VOCs
Well
Date
Benzene
Toluene
Ethyl-
benzene
Total
Xylenes
n-Butyl-
benzene
sec-
Butyl-
benzene
tert-Butyl-
benzene
P-
Isopropyl-
toluene
1.2-
Dichloro-
benzene
1.3 -
Dichloro-
benzene
1.4-
Dichloro-
benzene
1.3.5-
Trimethyl-
benzene
1.2.4-
Trimethyl-
benzene
Isopropyl-
benzene
n-
Propyl-
benzene
1.2.4-
Trichloro-
benzene
1.2.3-
Trichloro-
benzene
Naphthalene
1.2-
Dichloro-
ethane
Chloroform
Chloro-
benzene
Carbon
tetrachloride
ROD/MTCA
Cleanup Level
5
640a
700
1600a
NA
NA
NA
NA
NA
NA
NA
80a
NA
NA
NA
80a
NA
160a
0.481a
NA
NA
0.63a
NMW-
1A/NMW-102
Jan-09
1.32/1.32
2.41/2.43
9.96/9.94
6.96/6.94
<1,00/<1.00
2.06/20.7
<1,00/<1.00
<1,00/<1.00
<1,00/<1.00
<1,00/<1.00
1.62/1.67
<1,00/<1.00
7.32/7.35
5.30/5.33
2.80/2.77
<5.00/<5.00
<5.00/<5.00
<5.00/<5.00
<1,00/<1.00
NA
<1,00/<1.00
<1,00/<1.00
NMW-
1A/NMW-102
Jan-10
4.715.1
19/20
28/30
66/69
<0.10/0.10
5.0/5.5
0.67/0.73
<0.20/<0.20
0.62/0.62
4.7/5.2
10.0/11.0
6.1/6.5
120/110
32/33
6.7/7.0
12.0/13.0
3.5/3.8
29/33
<0.10/<0.10
<0.10/0.10
<0.10/0.10
<0.10/0.10
NMW-
1 A/NMW-102
Dec-10
4.5/4.1
24.2/21.2
157/137
161/141
4.7/4.1
6.1/5.3
<1,0/<1.0
5.3/4.7
1.3/1.3
12.7/11.6
37.5/34.2
14.2/13.1
137/123
32.2/28.1
30.3/26.4
3.8/3.6
<1.0/<1.0
39.5/41.9
<1,0/<1.0
1.6/1.4
<1,0/<1.0
<1,0/<1.0
NMW-
1 A/NMW-102
Jan-12
<1.0/<1.0
3.0/2.8
36.5/35.6
21.9/20.8
2.0/2.0
3.5/3.6
<1,0/<1.0
1.2/1.2
<1.0/<1.0
3.3/3.2
12.9/12.4
4.8/4.6
22.4/22.7
8.3/8.2
9.1/9.4
3.7/3.7
<1.0/<1.0
8.6/8.5
<1,0/<1.0
<1,0/<1.0
<1,0/<1.0
<1,0/<1.0
NMW-
1 A/NMW-102
Dec-12
<1.0/<1.0
<5.0/<5.0
10/8.9
13/11
<1,0/<1.0
<1,0/<1.0
<1,0/<1.0
<1.0/<1.0
<1.0/<1.0
1.3/1.4
3.7/3.8
<1,0/<1.0
6.6/5.8
1.5/1.4
1.1/<1.0
<1,0/<1.0
<1.0/<1.0
<5.0/<5.0
<1,0/<1.0
<5.0/<5.0
<1.0/<1.0
<1.0/<1.0
NMW-8A
Jan-09
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<5.0
<5.0
<1.0
NA
<1.0
<1.0
NMW-8A
Jan-10
<0.10
<0.10
<0.10
<0.30
<0.10
<0.10
<0.10
<0.20
<0.20
<0.20
<0.20
<0.10
<0.10
<0.10
<0.10
<0.20
<0.40
<0.40
<0.10
<0.10
<0.10
<0.10
NMW-8A
Dec-10
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-8A
Jan-12
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-8A
Dec-12
<1.0
<5.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<1.0
<5.0
<1.0
<1.0
NMW-9A
Jan-09
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<5.0
<5.0
<1.0
NA
<1.0
<1.0
NMW-9A
Jan-10
<0.10
<0.10
<0.10
<0.30
<0.10
<0.10
<0.10
<0.20
<0.20
<0.20
<0.20
<0.10
<0.10
<0.10
<0.10
<0.20
<0.40
<0.40
<0.10
<0.10
<0.10
<0.10
NMW-9A
Dec-10
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-9A
Jan-12
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-9A
Dec-12
<1.0
<5.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<1.0
<5.0
<1.0
<1.0
NMW-10A
Jan-09
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<5.0
<5.0
<1.0
NA
<1.0
<1.0
NMW-10A
Jan-10
1.7
8
44
20.2
<0.10
3.9
0.57
0.72
<0.20
<0.20
<0.20
<0.10
30
11
5.8
<0.20
<0.40
11
<0.10
<0.10
<0.10
<0.10
NMW-10A
Dec-10
1.4
1.6
14.5
3.4
<1.0
3.2
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
12.1
8.3
3.8
<1.0
<1.0
4.4
<1.0
<1.0
<1.0
<1.0
NMW-10A
Jan-12
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-10A
Dec-12
<1.0
<5.0
2.4
<3.0
<1.0
3.9
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
1.9
11
1.4
<1.0
<1.0
<5.0
<1.0
<5.0
<1.0
<1.0
NMW-11A
Jan-09
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<5.0
<5.0
<1.0
NA
<1.0
<1.0
NMW-11A
Jan-10
<0.10
<0.10
<0.10
<0.30
<0.10
<0.10
<0.10
<0.20
<0.20
<0.20
<0.20
<0.10
<0.10
<0.10
<0.10
<0.20
<0.40
<0.40
<0.10
0.19
<0.10
0.34
NMW-11A
Dec-10
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-11A
Jan-12
<1.0
<1.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
NMW-11A
Dec-12
<1.0
<5.0
<1.0
<3.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<5.0
<1.0
<5.0
<1.0
<1.0
Notes:
All concentrations in |jg/L
Bold and highlighted indicates concentration exceeded the cleanup level
a Cleanup level based on the most recent MTCA guidance
OU 1, Well 12A
200
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OU4, South Tacoma Field 201
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3.Tacoma Landfill, Operable Unit 5/6
3.1. Introduction
This is the fourth Five-Year Review (FYR) for the Tacoma Landfill Operable Unit (OU) 5/6 (EPA ID No.
WAD980726301) of the South Tacoma Channel (STC) Superfund Site located in Tacoma, Washington.
The STC Superfund site also includes Well 12A (OU 1) and South Tacoma Field (OU 4). Each STC OU
is treated as a separate site but for purposes of Five-Year Reviews, all three are being submitted together
under one cover. The triggering action for this review is the date of the last FYR, dated September 2008.
The FYR is required due to the fact that hazardous substances, pollutants, or contaminants remain at the
site at levels above those that would allow for unlimited use and unrestricted exposure.
3.1.1. Purpose
The purpose of the FYR is to determine whether the remedy at a site is protective of human health and the
environment. The methods, findings, and conclusions of reviews are documented in FYR reports. In
addition, FYR reports identify issues found during the review, if any, and identify recommendations to
address them.
3.1.2. Authority
The United States Environmental Protection Agency (EPA) is preparing this five-year review pursuant to
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) §121 and the
National Contingency Plan (NCP). CERCLA §121 states:
If the President selects a remedial action that results in any hazardous substances,
pollutants, or contaminants remaining at the site, the President shall review such
remedial action no less often than each five years after the initiation of such remedial
action to assure that human health and the environment are being protected by the
remedial action being implemented. In addition, if upon such review it is the judgment
of the President that action is appropriate at such site in accordance with section
[104] or [106], the President shall take or require such action. The President shall
report to the Congress a list offacilities for which such review is required, the results
of all such reviews, and any actions taken as a result of such reviews.
The EPA interpreted this requirement further in the NCP; 40 CFR §300.430(f)(4)(ii) states:
If a remedial action is selected that results in hazardous substances, pollutants, or
contaminants remaining at the site above levels that allow for unlimited use and
unrestricted exposure, the lead agency shall review such action no less often than
every five years after the initiation of the selected remedial action.
With oversight from the EPA Region 10 Remedial Project Manager, the United States Army Corps of
Engineers (USACE), Seattle District conducted a Five-Year Review of the remedial actions implemented
202
OU 5/6, Tacoma Landfill
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at the Tacoma Landfill (OU 5/6) of the STC Superfund Site located in Tacoma, WA. This review was
conducted from January 2013 through September 2013. This report documents the results of the review.
3.2. Site Chronology
Table 3-1 lists major activities and milestones for the Tacoma Landfill site, OU5/6.
Table 3-1. Chronology of Site Events, Tacoma Landfill, OU5/6
Event
Date
Tacoma Landfill begins operation
1960
Investigation detects hazardous substances in groundwater and soils near site
1983
Landfill placed on the National Priorities List
1983
Landfill gases cause small explosion at a neighboring business
1986
City of Tacoma begins Remedial Investigation and Feasibility Study (RI/FS) pursuant to Consent
Order with the State
1986
RI/FS completed
1988
EPA issues Record of Decision (ROD)
1988
Consent Decree finalized among Tacoma, Washington State Department of Ecology (Ecology)
and EPA
1991
Landfill cap and gas management system construction completed
1993
Groundwater extraction and treatment system construction completed
1995
First Five-Year Review completed
1997
First 5-year Extension on Closure requested Septemberl997, issued May 1998
1997/1998
Treatment of groundwater at on-site facility discontinued
1998
Extracted groundwater discharge diverted from sanitary sewer to storm sewer
2002
Second Five-Year Review completed
2003
Second 5-year Extension on Closure requested August 2004, issued February 2005
2004/2005
Third Five-Year Review completed
2008
Third 5-year Extension on Closure requested February 2009, issued December, 2009
2009
Replacement/Decommissioning of Landfill Gas Probes
2009
Landfill Gas Monitoring Plan Revisions
December 2009
GETS Shutdown (except W-l, W-2, W-4, W-15, and W-16)
March 2010
New Landfill Flare Operational
August 2010
Groundwater Monitoring Plan Revisions
November 2010
Replacement of Landfill Gas Extraction Wells PW-60 and PW-62
2011
Central Area Closure
2012/2013
OU 5/6, Tacoma Landfill
203
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3.3. Background
3.3.1. Physical Characteristics
The City of Tacoma Refuse Utility operates a solid waste disposal facility known as the Tacoma Landfill
(Landfill) located within the City of Tacoma in Pierce County, Washington. Specifically, the Landfill is
situated in Sections 12 and 13 of Township 20 North, Range 2 East, near the western border of Tacoma.
The Landfill covers 240 acres and is bounded approximately by South 31st Street on the north, Tyler
Street on the east, South 48th Street on the south, and Orchard Street on the west. Surface water located
near the landfill includes Leach Creek to the west and Flett Creek to the south (Figure 3-1).
The site is located within the South Tacoma Groundwater Protection District, which is a special zoning
overlay district managed by the Tacoma Pierce County Health Department (TPCHD). The City of
Tacoma operates several drinking water wells within a half mile east of the site in the South Tacoma
Channel that are used to augment the City's drinking water supply during peak demand periods.
Groundwater in the South Tacoma Channel provides the primary contingency to maintain the municipal
drinking water supply in the event that the main source (Green River) is not available.
3.3.1.1 Site Geology
The Tacoma Landfill site is located in the northern portion of the Chambers/Clover Creek Drainage
Basin. This area is part of the Puget Sound Lowlands. The South Tacoma Channel, a glacial outwash
channel capable of producing high groundwater yields, is located to the east of the site.
The geology of the site consists of a series of glacial materials, mostly sand and gravel laid down over
older alluvial silts and sands. The stratigraphic units (layers) were described in the Remedial Investigation
and refined in the End of Plume Residual Characterization Report (Landau 2006). Figure 3-2 shows a
representative geologic cross-section. From youngest to oldest (top down) the units are:
• Vashon recessional deposits (Qvr). Consists of unconsolidated (stiff to very stiff; medium to
dense to dense) silt, sand, and gravel.
• Vashon till (Qvt). Consists of very dense silt, sand, and gravel.
• Vashon advance outwash (Qva). Consists of consolidated (dense to very dense) gravelly sand and
sand. Has a fining downward sequence where the grain size is coarsest at the top and becomes
finer toward the bottom. Includes Colvos Sand.
• Pre-Olympia older gravel (Qog). Consists of dense to very dense gravel deposits.
• Pre-Olympia lacustrine deposits (Qol). Consists of fine-grained silt deposits.
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South Tacoma Channel Superfund Site Five-Year Review
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3.3.1.2
Hydrogeology
The Qva and Qog deposits represent a single aquifer unit at the Site. The upper portion of the aquifer in
the Qva has also been referred to as the Colvos Sand aquifer. The older lacustrine unit, Qol, serves as the
regional aquitard in the landfill area.
Recharge to the aquifer beneath the landfill occurs from the Fircrest Upland, north of the landfill, and the
South Tacoma Channel, east of the landfill. The dominant groundwater flow direction is to the south and
west and towards Leach Creek located approximately 1/2 mile west of the Landfill. Leach Creek flows
into Chambers Creek which enters Puget Sound approximately five miles southwest of the Landfill. A
north-south groundwater divide (dividing east from west) is located between the City of Tacoma
production wells in the South Tacoma Channel and the Tacoma landfill. During periods of heavy water
use by City of Tacoma wells (i.e., heavy groundwater pumping at those wells), the groundwater flow
divide shifts westward toward the landfill.
The depth to groundwater beneath the landfill is about 70 feet. Units above the water table include the
Vashon Till (Qvt) and portions of the Advance Outwash (Qva). In areas where the till lies below the
refuse, the relatively low hydraulic conductivity of the till slows the downward migration of water. Where
the till is absent, water moves through the unsaturated zone into the aquifer.
3.3.2. Land and Resource Use
The Tacoma Landfill began operations in 1960, and has been operating as a sanitary landfill under a
permit issued by the TPCHD. The wastes disposed at the Landfill include garbage, rubbish, industrial
wastes, construction and demolition wastes, street refuse, litter, and bulky waste. The Landfill does not
accept hazardous waste for disposal; however, the Landfill received wastes in the 1960s and 1970s that
have since been designated as hazardous wastes under state and federal law. The site has been filled. The
last section of the site to be filled is called the Central Area which covers approximately 31 acres, which
was developed in 1987. The Central Area was covered with a double flexible membrane bottom liner and
leachate collection system. The Central area did not accept waste from December 2002 through 2010. The
Central area is now filled and is scheduled for final closure in December 2013. In addition to waste
disposal, the site is the operations center for all solid waste management activities in the City of Tacoma.
Solid wastes transported to the site are segregated, processed, and removed from the site.
The Landfill is surrounded primarily by residential and commercial development with some open land
and industrial development. Groundwater beneath the site is hydraulically connected to the drinking water
aquifer used by both the City of Tacoma and the City of Fircrest. Groundwater level measurements
indicate that the City of Tacoma wells located to the east within half a mile of the site in the South
Tacoma Channel (Wells 2B/C, 4A, 6A/B and 11A) potentially influence the groundwater flow direction
at the Landfill. The City of Fircrest wells, located northwest of the site, are generally cross-gradient from
the Landfill. Private residential wells are also present in the area. However, residences whose wells have
been impacted have been connected to municipal water. Drilling of new wells in the area affected by
contamination from the site is currently prohibited by the Cities of Tacoma, Fircrest, and University
Place.
OU 5/6, Tacoma Landfill
205
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3.3.3.
History of Contamination
In 1983, EPA conducted an investigation and detected hazardous compounds in samples of groundwater
and soil near the Landfill. This led EPA to including the Landfill on the National Priorities List (NPL) of
hazardous sites as part of the South Tacoma Channel site. Through a cooperative agreement with EPA,
the Washington State Department of Ecology (Ecology) began an investigation into contamination at the
site in 1984. In 1986, the City of Tacoma assumed responsibility for conducting the remedial
investigation/feasibility study (RI/FS) under a response Order on Consent issued by Ecology.
3.3.4. Initial response
Groundwater contamination, primarily volatile organic compounds (VOCs), was detected during the RI at
the perimeter of the Landfill and extended in a southwesterly direction toward Leach Creek.Because of
the concern about public health effects of the contamination, particularly vinyl chloride, residents whose
wells were impacted or threatened were hooked up to the Tacoma municipal water system in the mid-
1980s. Landfill gases were found to be migrating from the Landfill to residences and businesses adjacent
to the site. The landfill gases contained methane, which can cause explosions at certain concentrations,
and VOCs, which can cause negative health effects at elevated concentrations. Because of a concern over
the migration of landfill gases, the first stage of a landfill gas management system was constructed in
1986.
3.3.5. Basis for Taking Remedial Action
Monitoring at the site revealed that hazardous substances had been released from the Landfill into the
soils, groundwater, and air at the site. The hazardous substances released to groundwater include a variety
of VOCs and semi-volatile organic compounds (SVOCs) and heavy metals, many of which were at
concentrations above State and Federal drinking water standards. Vinyl chloride was the most pervasive
compound found in groundwater and represented the greatest risk to human health. Landfill gases were
found to contain a wide variety of VOCs as well as methane. VOCs represent a risk to human health if the
gases seep into neighboring homes and businesses. The methane in the gases represents the greatest risk
to human health as it can cause explosions when it accumulates to certain concentrations. Accumulation
of landfill gas in a utility vault at a company located adjacent to the Landfill resulted in a small explosion
in May 1986.
The following contaminants of concern (COCs) were identified in the Endangerment Assessment from
the Remedial Investigation (RI):
• Vinyl Chloride
• Benzene
• 1,2-Dichloroethane (DCA)
• Methylene Chloride
• 1,1-DCA
• Chloroethane
• Toluene
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South Tacoma Channel Superfund Site Five-Year Review
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EPA and Ecology later added three additional COCs in the Record of Decision (ROD):
• Xylenes
• 1.1.1 -Trichlorocthane
• Ethylbenzene
3.4. Remedial Actions
3.4.1. Regulatory Actions
On March 31, 1988, EPA issued the ROD which selected the final remedial action for the site based on
the RI/FS. On November 13, 1989, a Consent Decree among EPA, Ecology, and the City of Tacoma was
lodged in federal court. The Decree addressed implementation of the remedial actions specified in the
ROD. This Consent Decree was not accepted by the Court and was subsequently modified. The modified
Decree was entered by the Court on May 17, 1991.
3.4.2. Remedial Action Objectives
The ROD required treatment (extraction and treatment) to reduce contaminant levels in the groundwater
to or below cleanup standards with treatment performance levels for COCs based on federal Maximum
Contaminant Levels (MCLs) and discharge to surface water. The goal of the extraction is defined as
preventing any further degradation of existing water quality beyond the boundaries of the existing plume.
The ROD specifies treatment standards based on the point of discharge, but allowed for discharge to
Leach Creek, Flett Creek, or the sanitary sewer. Extraction and treatment was required to continue until
water quality at the edge of the filled area are at or below MCLs or previously established and approved
health-based standards. In addition, consideration of potential impacts to public and private water supplies
and to adjacent Leach Creek were required in any future decision about when to shut off the system. The
remedial action objectives outlined in the ROD are as follows:
• Prevent further migration of the plume via the groundwater extraction and treatment system.
• Reduce the production of leachate by placing constraints on site operations and by properly grading
and capping the landfill.
• Eliminate off-site gas migration through the gas extraction system.
• Further protect public health and the environment via monitoring of groundwater, surface water, gas
probes, air emissions, and by providing alternate water supplies where necessary.
A methodology to determine treatment performance standards for indicator compounds was developed in
the ROD. If MCLs were not available, the lower of either ambient water quality criteria (AWQC) for
protection of human health for water and fish consumption or chronic fresh water criteria for the
protection of fish was used. For compounds that did not have either an MCL or AWQC, a value was
derived based on an EPA Region 10 risk assessment. The ROD also states that if discharge is to either
Leach Creek or Flett Creek, the effluent must meet or exceed MCLs or chronic fresh water criteria,
whichever is lower, and meet water quality standards for waters of Washington State (WAC 173-201).
OU 5/6, Tacoma Landfill
207
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3.4.3.
Remedy Description
The selected remedy included management of contaminant migration using a groundwater extraction and
treatment system; source control using a landfill cap, gas extraction system, and landfill closure plan; and
monitoring. Institutional controls (ICs) were selected to assure that the remedial action will continue to
protect human health and the environment. The remedy, as described in the ROD, is presented below.
3.4.3.1 Management of Migration
Migration control will be achieved through a groundwater extraction and treatment system
(GETS) and a system or method to confirm performance. Minimum flows as required by WAC
173-512 shall be maintained in Leach and Flett Creeks. The treatment process shall be
permanent and shall effectively reduce the toxicity, mobility, and volume of contaminants. It shall
also employ all known, available, and reasonable methods to treat the contaminated
groundwater, and to prevent the spread of contamination. Discharge of treated groundwater may
be either to Leach Creek, Flett Creek, or the sanitary sewer. If the discharge is to either Leach
Creek or Flett Creek, the effluent must meet or exceed MCLs developed pursuant to the Safe
Drinking Water Act or meet the chronic fresh water criteria as set forth in EPA's Quality Criteria
for Water, 1986 (EPA 440/5-86-001), whichever is more stringent. The extraction and treatment
system can be shut off when water quality outside the compliance boundary (defined by WAC
173-304 as the edge of the filled area) consistently meets or exceeds drinking water standards or
approved health based criteria.
3.4.3.2 Source Control
Source control measures consist of constructing a cap on the landfill to minimize infiltration and
maximize run-off. Unlined areas of the landfill will be capped as soon as possible. Increased run-
off due to the construction of the cap will be routed off the landfill to reduce infiltration. The run-
off collected from the landfill will be directed to the appropriate storm or sanitary sewers
consistent with local storm water drainage ordinances or pre-treatment regulation. Filling
unused areas will require a liner consistent with WAC 173-304. A schedule for closure of the
landfill under WAC 173-304 is considered part of the remedial action at this site. The schedule
will address various waste reduction measures and develop contingency plans if these do not
produce the expected results.
The production of methane gas at the landfill is being addressed through the installation of a gas
extraction system and is being monitored using a series of gas probes installed around the
landfill. The gas collected by the extraction system is burned at the flare which meets air quality
requirements. The quantity and quality of condensate from the gas collection lines and flare will
be determined during the remedial action and treated, if necessary. Additional gas probes will be
installed in the surrounding neighborhoods to verify that the extraction system is preventing off-
site gas migration.
3.4.3.3 Monitoring
Groundwater monitoring wells shall be installed in locations appropriate for obtaining the
following information:
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South Tacoma Channel Superfund Site Five-Year Review
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• Determine if the groundwater extraction system is preventing the spread of the
contaminant plume.
• Determine the extent of the plume migration to the east of the site.
• Identify any potential impacts to Leach Creek and the Fircrest well system.
• Ensure there is no dense-phase plume migrating away from the site in the deepest zones
of the aquifer.
Leach Creek will be monitored for both water quality and quantity. Other surface waters
receiving either effluent from the GETS or the surface drainage system will be monitored for
water quality. At a minimum, the private wells in the path of the plume will continue to be
monitored on a quarterly basis. Fircrest wells will be sampled monthly. Any well, public or
private, which becomes contaminated due to the landfill, will be replaced and water will be
supplied from existing City of Tacoma water supply systems.
3.4.3.4 Institutional Controls
ICs will be implemented to assure that the remedial action will continue to protect human health
and the environment. Tacoma, in cooperation with the town of Fircrest and Pierce County, will
pursue the establishment of an ordinance or other suitable methodology to restrict drilling of
water supply wells.
3.4.4. Remedy Implementation
Each component of the remedy is described below.
3.4.4.1 Groundwater Extraction and Treatment System (GETS)
The GETS system was constructed in 1992 and 1993 and consisted of 19 point of compliance (POC)
extraction wells (W1 through W19), 9 edge-of plume (EOP) extraction wells (W30 through W38),
pipelines to transport the extracted groundwater to a treatment facility, and a groundwater treatment
system (see Figure 3-3). The POC wells are located on the down-gradient edge of the Landfill and their
purpose is to capture contaminated groundwater before it flows outside of the Landfill boundary. The
EOP wells are located along Leach Creek and their purpose is to clean up contaminated groundwater at
the edge of the plume and prevent contamination from impacting Leach Creek and groundwater beyond
the creek. Once extracted from the EOP and POC wells, groundwater was originally transported via
pipelines to a treatment facility. The treatment facility is equipped with two air-strippers to remove
VOCs; an acid-wash system to periodically remove scale buildup from the internal packing material in
the towers; and a control building where overall operations, control, and monitoring of the groundwater
extraction/treatment facilities are managed. The treated groundwater was then discharged to the sanitary
sewer system for further treatment and disposal.
Based on groundwater monitoring and several years of experience in operating the groundwater
extraction and treatment system, improvements were made to the system between 1995 and 1997. These
included rehabilitation of EOP wells, installation of four new EOP extraction wells (W40 through W43)
near the southern extent, and installation of three new POC wells (W20 through W22) at the north end of
the landfill near Fircrest municipal well field.
OU 5/6, Tacoma Landfill
209
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Under an amendment to the Consent Decree, the City was required to maintain 1.7 cubic feet per second
(cfs) of flow in Leach Creek since groundwater was being extracted from wells east of the creek (EOP
extraction wells) and discharged to the sanitary sewer. Leach Creek flow was supplemented, as needed,
using a well the City installed at the Leach Creek Holding Basin pump station. Groundwater was
extracted from this well at approximately 2.5 cfs. Flow in the creek is monitored at the USGS gauging
station located at 40th Street.
Configuration of the pipeline to the treatment facility allowed groundwater extracted from highly
contaminated areas to mix with groundwater from less contaminated areas, which effectively dilutes
contaminant concentrations prior to treatment. By 1998, the combined water from all groundwater
extraction wells met performance standards specified in the ROD for discharge into the sanitary sewer for
six consecutive quarters and the treatment system was mothballed. The extracted groundwater was then
discharged directly into the sanitary sewer for treatment and disposal. By August 2002, the combined
water from all the groundwater extraction wells met performance standards specified by the ROD and by
Ecology for discharge to surface water for four consecutive quarters. In response, the City requested to
temporarily change the discharge of extracted groundwater from the sanitary sewer to Leach Creek and to
evaluate the feasibility of a permanent discharge location. EPA and Ecology approved that request and the
City periodically discharged all or a portion of extracted groundwater to Leach Creek. By 2003, a
permanent discharge channel and holding basin was constructed and all of the extracted groundwater was
discharged to Leach Creek. The City subsequently ceased augmentation of flow in the creek and flow
monitoring. The augmentation well remains available to supplement flows in the creek, if needed.
3.4.4.2 Landfill Cover
A landfill cover was installed over areas containing buried waste in two stages from 1990 to 1992 with
the exception of the cell in the Central Area. Figure 3-4 shows the sequence of fill operations at the
landfill. The cover was installed on approximately 125 acres of the 240 acre site. The purpose of the cover
is to minimize rainwater and surface water infiltration into the landfill thereby reducing the production of
leachate which is the source of groundwater contamination. The cover consists of two 60 milliliter (mil)
high density polyethylene (HDPE) liners separated by a leak detection and water collection layer. A 4-
acre area that that became part of an expanded operations area was capped using a geomembrane layer
and then covered by buildings or low-permeability asphalt pavement.
The City constructed the Central Area in the center of the landfill to receive municipal solid waste. The
Central Area is the only portion of the site with a bottom liner and was designed to meet the state
requirements for solid waste disposal given in WAC 173-304 (Minimum Functional Standards for Solid
Waste Handling). The Central Area was designed and constructed in two phases. The first phase,
encompassing approximately 18 acres, was constructed in 1987. The second phase, which consisted of
extending the sidewall liners and leachate collection system, was constructed in 1990, bringing the total
lined area within the Central Area to approximately 31 acres. The bottom liner is composed of two HDPE
liners separated by a leak detection and leachate collection system. The side slopes in the Central Area
consist of a single HDPE liner which separates the Central Area from the old landfill.
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The leachate generated within and under the east sidewall liner of the Central Area is discharged to the
24-inch sanitary sewer through a manhole located in the Resource Recovery Area, typically referred to as
the leachate collection manhole. The 24-inch sanitary sewer discharges from the east side of the landfill
into the Tyler Street sanitary sewer.
Waste was not put into the Central Area between December 2002 and 2010. Final closure of the Central
Area began in 2010. Currently it is filled to grade and final closure will be completed in December 2013.
In accordance with requirements in the Consent Decree, the final cover must be similar to the one
installed over the rest of the Landfill. Due to advancements in materials for landfill caps, the City
requested a modification to use an alternate cap that is equivalent or better than the existing cover system
and meets the criteria in WAC 173-351-500 for alternative covers. The final cover at the Central Area
will contain a geosynthetic clay liner (GCL), a 60-mil HDPE geomembrane, and a geocomposite drainage
layer.
Storm water from the northern and western portions of the landfill site drain to the Leach Creek Holding
Basin, from which it is then discharged into Leach Creek. Runoff draining to Leach Creek leaves the
landfill property through five separate discharge points, and is then conveyed to the basin via the City
storm sewer system. The southern portion of the landfill site drains to Flett Creek via the City storm
sewer system. Runoff draining to Flett Creek leaves the landfill property through two separate discharge
points. The first point is via the east detention pond and the second point is the City storm sewer system at
the south end of the landfill.
3.4.4.3 Landfill Gas Management
A landfill gas management system was installed in several phases starting in 1986. Additions to the
system have been and will continue to be made if monitoring results indicate that the existing system is
not controlling landfill gas migration to within the limits set forth in the Minimum Functional Standards.
The system currently has over 300 gas extraction well stations each consisting of one to four wells
completed to various depths, piping for transferring the collected gas to a flare station, and the flare
station where the gas is destroyed. It has been expanded into the Central Area as other areas are filled to
final grade. See Figure 3-5 for the gas extraction well locations. The effectiveness of the landfill gas
management system is evaluated through regular monitoring of gas probes situated around the perimeter
of the landfill and off-site. Off-site probes are located up to 1,000 feet from the edge of the landfill. Each
probe consists of one to five monitoring ports completed to various depths. See Figure 3-6 for the gas
monitoring probe locations.
The initial system, installed in 1986, was constructed under emergency conditions and included 128 gas
extraction wells within the landfill wastes and in native soil along the site perimeter and 66 gas probe
locations around the perimeter of the site. During the first year of operation, the initial system proved to
be effective in controlling or reducing gas migration throughout the landfill, particularly in the upper
regions of the surrounding soil. However, perimeter and off-site monitoring test results indicated that this
system was not effectively controlling the deep migration of landfill gas. In 1988, the City began work on
the design and installation of the second phase of the landfill gas control system. This phase was
specifically designed to eliminate the deep gas migration problem and to increase off-site monitoring
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capabilities. It included the installation of 82 deep landfill gas extraction well stations, 11 off-site landfill
gas monitoring probe stations, and additional collection header piping.
Since 1988, additional gas extraction wells and gas monitoring probes have been installed under several
different projects. These include 41 new probes installed as required in the Consent Decree, additional
extraction wells installed prior to each stage of landfill capping, and replacement of damaged extraction
wells and probes. In 2006, the City installed three new gas extraction wells near the Home Depot property
in response to methane detections in gas probes located in the parking lot. Most recently, gas extraction
wells were installed as part of the final closure of the Central Area. With the addition of these new gas
wells, the entire capped area is covered by the gas extraction system, with well spacing based on a
conservative radius of influence (125 feet).
The gas extracted from the wells is discharged into gas header pipes for transport to the flare system. As
the warm moist gas moves through the cooler header pipes, condensate is formed. Condensate collection
pipes are installed below the ground to collect the moisture from the gas header pipes through condensate
drip legs. The collected gas condensate is transported through the condensate collection pipes to the
vacuum valve stations by gravity. At the vacuum valve stations, pumps are utilized to pump the gas
condensate to the discharge locations. All the gas condensate discharges into the sanitary sewer. In 1993,
the condensate discharge pipes were re-rerouted to the leachate collection manhole to provide a single
discharge for all the leachate and condensate waste streams. A condensate collection system was also
installed with each phase of landfill closure. This eliminated the condensate drain traps previously in use
in which the condensate was drained back into the landfill.
The flare station was originally installed in 1986 as part of the initial construction phase and included two
1,000 cubic feet/minute (cfm) Sur-Lite flares. In 1992, two additional 1,670-cfm Perennial gas flares were
installed to increase the flow capacity of the system. The City signed a contract in 1995 to lease the
landfill gas field to a private company for the purpose of constructing an electrical generation facility at
the Landfill. This facility became operational in 1998, but was shut down in 2003 due to low energy sales,
the end of gas credits, and low gas production. Currently, all gas is collected and sent to the flare station
for destruction. In 2009, construction started on a new, lower-capacity blower and flare system to
effectively process the collected gas, which is declining in both overall gas volumes and British thermal
units (BTU). The new blower and flare became operational in 2010.
3.4.4.4 Landfill Closure
The schedule identified in the ROD required landfill closure by December 31, 1999, and included
provisions for three five -year extensions. The Consent Decree stipulates that the Tacoma Landfill will be
closed in stages. During each stage, final grading and cap installation will take place in the specified
areas. The three stages and their effective dates, as defined by the Consent Decree, are:
• Stage 1, 1990-1991 construction season - Northeast and southern sections of the landfill and the
Public Receiving Facility. (Completed in April 1991)
• Stage 2, 1991-1992 construction season -Western section of the landfill and the section east of the
Central Area. (Completed in June 1992)
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• Stage 3, closure of the Central Area required by December 31, 1999. Extensions of this deadline up to
a combined 15 years in increments of no longer than 5 years were allowed, making the final closure
deadline December 31, 2014 (the landfill is currently scheduled for closure in December 2013).
The Consent Decree required that the following conditions be met in order for a closure extension to be
granted:
• That the continued operation of the landfill shall not result in a release or substantial threat of
hazardous substances, pollutants or contaminants to the environment;
• That the performance standards for the extraction-treatment system have been achieved;
• That since the effective date of the Consent Decree, the Settling Defendant has instituted and is
operating an aggressive solid waste recycling and hazardous materials collected project; and
• That other feasible solid waste management alternatives to disposal at the landfill do not exist.
The City met all of the requirements for closure extensions. Operation of the GETS and gas management
system controlled the potential for releases and performance levels for GETS operation were met. Since
1988, the City has been implementing programs to collect and process recyclable materials and hazardous
waste. These include: collection programs such as curbside recycling, collection of yard waste, produce
waste recycling, and waste oil recycling; Landfill Waste Diversion Facilities such as the recycling center
and household hazardous waste collection facility; and On-Site Diversion and Source Control Efforts for
recyclable and hazardous materials. The City also participates in waste reduction and environmental
stewardship programs and promotes their programs through community education and outreach. The
Central Area was allowed to stay opened during the extension periods for use as an emergency disposal
facility.
The third and final five-year extension request was originally submitted on February 27, 2009, and
amended on June 8, 2009. EPA conditionally granted approval of the extension in a letter dated December
21, 2009. Conditions included: complete final closure by December 31, 2014, bring the southern half of
the Central Area to grade by 2010 and the northern half by 2012, continue to submit Central Area flow
and leachate data, update the groundwater management plan, and update the IC plan. The City requested
several modifications to the conditions, which were subsequently approved by EPA in a letter dated July
28, 2010. Modifications to the request included allowance for continuous fill to replace partial closure in
two separately staged phases of construction. Date modifications were also made to require the Central
Area to be entirely at final grade elevation with a temporary cover by December 2012, with construction
completion by December 31, 2013.
3.4.4.5 Monitoring
Monitoring of groundwater and surface water is used to evaluate the performance of the GETS. Wells at
the site are shown on Figure 3-3 and include: monitoring wells (TL-series), performance monitoring wells
(P-series), groundwater extraction wells (W-series), existing residential wells (EW-series), and Fircrest
water supply wells (FW-series). Surface water sampling is conducted along Leach Creek at three stations
(LC-series). The Consent Decree requires quarterly monitoring and then biannual monitoring for the
subsequent 30 years following issuance of the certificate of completion. The Consent Decree states that
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the extraction/treatment system can be shut down when the groundwater at the point of compliance and
within the existing plume has reached the drinking water standards or health based criteria for four
consecutive quarterly samples.
The City of Tacoma is required to provide an alternate water supply to all residents whose wells became
or become contaminated by the Landfill. The City has connected most of the affected residents to the
Tacoma municipal water system. According to the criteria established for this site, a well is considered
contaminated when the concentration of a chemical exceeds 20% of its drinking water standard or health-
based level. Some private wells are still in use in the vicinity of the Landfill; however, their use is
typically restricted to outdoor purposes only, such as lawn or garden watering.
The city of Fircrest has water supply wells located to the northwest of the Landfill. In 1995, Tacoma
asked the neighboring City of Fircrest to limit the amount of water being pumped from its municipal well
closest to the Landfill, Fircrest Well # 5 (FW-05), because of the potential threat of pulling in landfill
contaminants at higher pumping levels. In 1996, Tacoma drilled a new well to replace Fircrest Well #5.
The old well has been temporarily closed.
3.4.4.6 Institutional Control Plan
The ROD generally identifies that ICs should be developed. The Consent Decree specified that ICs should
be developed to prevent installation of drinking water wells within the vicinity of the Landfill.
Section V, Paragraph 21 of the Consent Decree requires that the City implement the following types of
ICs at the Tacoma Landfill:
1. Place a notice on any deed, title, or other instrument of conveyance relating to the Tacoma Landfill
indicating that the site is subject to a Consent Decree (i.e., Restrictive Covenant). The notice must
include a reference to and a description of the Consent Decree, as well as a statement that the landfill
has been used to manage hazardous substances, some of which remain under the cap. The notice
must also include a statement that land use is restricted and that any actions that disturb the cap or
the containment system, including the monitoring system, will not be allowed unless the
Environmental Protection Agency and the Department of Ecology find that such disturbance does not
increase the potential hazard to human health and the environment, or is necessary to reduce a threat
to human health and the environment. An assurance will be provided in the notice that the
restrictions and obligations set forth in the Consent Decree will be binding upon persons who acquire
any interest in the Tacoma Landfill property.
2. In accordance with Sections 4 and 5 of the Restrictive Covenant, the City will provide advance
notice to the Environmental Protection Agency and Department of Ecology whenever the City sells or
leases any portion of the Tacoma Landfill to a third party. The notice must also indicate whether any
of the City's obligations will be performed by the third party acquiring the real property.
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3. Place restrictions on the use of groundwater at the property, including a prohibition against
pumping groundwater in affected aquifers unless it's done to monitor groundwater contamination
and/or the effectiveness of the remedial action at the landfill.
4. Use best efforts to implement ICs on properties outside the City's jurisdiction including the
recording of notices, plot plans, and other similar documents, and providing notice of the ICs to other
affected local zoning authorities or other affected governmental entities.
Another underlying function of the IC Plan is to outline the approach for evaluating future development
concepts for various portions of the landfill to ensure that remedial actions and monitoring systems that
are in place remain protective and are not compromised by future uses. This includes not only a plan for
obtaining public input, as determined appropriate on a case-by-case basis, evaluation of consistency with
remedial systems in place, engineering to resolve any modifications to either the remedy (i.e., burying
portions of the gas system), or the design of the development (i.e., boots around cap penetrations), and
agency review and approval.
The City originally developed an IC Plan dated July 17, 1992, which outlined procedures to prohibit
drilling of water supply wells within and adjacent to the Landfill and to prohibit any activity that will
negatively impact the remedies constructed at the Landfill. The Plan was conditionally approved by EPA
and Ecology on August 17, 1992. An updated IC and Land Use Plan was submitted by the City in
November 2010. The plan was conditionally approved by EPA and and finalized on July 30, 2012.
Details of the plan are presented in Section 6.7.
3.4.5. Systems Operations/Operations & Maintenance
A compilation of the operation and maintenance (O&M) procedures for the Landfill are provided in the
2004 Operations and Closure Plan, which was revised in 2009. This plan was required as part of the
Consent Decree and was developed to comply with the requirements of the Minimum Functional
Standards for Solid Waste Handling (WAC 173-304) and the Criteria for Municipal Solid Waste Landfills
(WAC 173-351). It is periodically updated as the remedial action or landfill operations change and
includes summaries of the maintenance and management, environmental monitoring, and recycling
programs, and it presents the site closure and post-closure plan.
3.4.5.1 Groundwater Extraction and Treatment System
O&M for the GETS is conducted according to the 1993 Groundwater Extraction/Treatment System
Operation and Maintenance Plan. Groundwater extraction wells in operation are monitored weekly for
pumping rates and water elevations. Extraction rates have gradually decreased over time, primarily due to
iron bacteria precipitation in the wells and well laterals. The City periodically treats the wells using the
carbon dioxide freezing method to remove the natural soil bacteria on the well screens, which then allows
the wells to increase their extraction rates. Extraction well W-l was replaced in 2009 due to ongoing
maintenance problems.
Individual extraction rates at operational wells during the last five years ranged from about 2 to 75 gallons
per minute (gpm). Plume capture is verified by evaluating extraction rates at the southern end of the
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landfill near the residual VOC plume (POC extraction wells W-l through W-9). The hydraulic gradient is
evaluated for each quarterly event and is used in the calculation method to determine the required
production rates to maintain capture. In 2008 and 2009, the gradient ranged from 0.0009 to 0.0018 ft/ft
and the required flow ranged from 101 to 192 gpm. Comparison of the required to actual extraction rates
verifies that capture has been obtained at the southern end of the landfill. A full capture zone analysis,
based on the EPA recommendation for the POC extraction wells has also been completed as part of the
Third Five-Year Closure Extension Request. The horizontal capture zone curve for each well was
calculated and plotted on the site map. Figure 3-7 shows the capture zone curves for the fourth quarter of
2008, which indicates that when all POC extraction wells are operational, full horizontal capture of
contamination from the landfill is obtained.
In December 2009 the City requested approval to shut down the GETS because groundwater
concentrations in most of the POC and EOP extraction wells had met the Consent Decree performance
levels for four consecutive quarterly sample rounds. Specifically, monitoring results demonstrated that 19
of the 21 POC extraction wells met VOC performance standards, 15 of the 21 POC extraction wells met
the arsenic performance standards, 32 of the 33 off-site monitoring wells met VOC performance
standards, 12 of the 13 EOP extraction wells met VOC performance standards, and all EOP extraction
wells and off-site monitoring wells met the arsenic performance standards. EPA approved the request for
shutdown on an interim basis in February 2010, pending the results of rebound monitoring (discussed
below). Fourteen of the 19 operational POC wells and 8 of the 9 operational EOP wells were shut down
in March 2010. POC extraction wells remaining in operation are W-l, W-2, W-4, W-15, and W-16. EOP
extraction well W-36 remained in operation due to low levels of vinyl chloride detected at nearby
residential well EW-12. Well W-36 was shutdown in 2011 after EW-12 was decommissioned and the
residence hooked up to the Fircrest water supply.
The City has decommissioned some of the EOP extraction wells (W-34, W-35, and W-42) due to property
development in the area. In 2012, EPA granted the City request that that EOP extraction wells W-30, W-
40, and W-41 be decommissioned. POC extraction wells that are shut down will be maintained in the
event that these wells need to be used in the future.
3.4.5.2 Landfill Cover
O&M for the landfill cover is conducted according to the 1992 Operations and Maintenance Plan for the
Landfill Cap, Condensate Collection System and Central Area Leachate Collection System. The capped
areas are inspected for evidence of erosion, settlement, ponding of water, improper or inadequate
vegetation, burrowing animals, cracking, odor, or any other adverse activities/conditions. Results of the
monitoring are reported annually.
O&M for the asphalt cap is conducted according to the 1992 Asphalt Cap Inspection and Maintenance
Plan. The asphalt cap is inspected for cracks, deterioration, subsidence, uneven or excessive wear,
bleeding, or expansion of joints on the retaining wall. The permeability of the asphalt cover is regularly
checked with lysimeters installed in the cover. Results of the monitoring are reported annually.
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Leachate and Condensate Monitoring
Leachate and Condensate are managed in accordance with the 1992 Leachate and Condensate
Management Plan. The objective of the plan was to characterize, classify, and determine the volumes of
leachate and condensate discharges from the site; determine collection, disposal, and treatment
requirements for each of the waste streams comprising leachate and condensate discharging to the
sanitary sewer; determine sewer discharge permitting requirements; and develop the sampling and
monitoring requirements. Sampling during the pre-design studies determined that the leachate and
condensate could be discharged to the City's Central Wastewater Treatment Plant (CTP) without
treatment.
Leachate discharged to the sanitary sewer consists of leachate from the Central Area collection system
and toe drain that connect to the leachate collection manhole and leachate from the leak detection system
that connects to the leak detection manhole. Surface runoff at the Central Area is collected and also routed
to the leachate collection manhole. The central Area leachate collection, detection, surface runoff, and toe
drain pipes are visually inspected each month by field crews. There were no significant equipment or
collection issues in the last five years.
Condensate is generated from the landfill gas extraction system. As the warm, moist extracted gas moves
through the cooler header pipes, condensate is formed and collected. The condensate is then routed to the
leachate collection manhole for discharge to the sanitary sewer. The condensate collection system
operated as expected during the last five years. Routine operation problems, such as plugged air release
valves, broken pipe fittings, electrical malfunctions, and pump failures were identified and corrected as
they occurred. The system remained operational during most repairs. System down time was minimal and
had little effect on condensate collection.
Leachate and condensate monitoring are completed according to the following schedule:
• Quarterly sampling of the combined effluent is analyzed for VOCs, semi-VOCs, metals, and
conventional analytes (ammonia, biological oxygen demand [BOD], chemical oxygen demand
[COD], free cyanide, total cyanide, oil and grease, and total suspended solids [TSS]). Analyses for
pesticides and PCBs is not required.
• Quarterly sampling of the toe-drain influent is analyzed for ammonia, BOD, COD, chloride, total
dissolved solids (TDS), hardness, pH, conductivity.
• Annual sampling of the combined effluent and toe drain, precipitation runoff, and condensate
influents is analyzed for flow rate, VOCs, semi-VOCs, metals, and conventional analytes. Analyses
for pesticides and PCBs are not required. Condensate is to be monitored only for VOCs.
In EPA and Ecology's approval of the second five-year extension, the City was required to monitor daily
volumes collected from the Central Area leachate collection system, leak detection system, and toe-drain
collection system. In the event that the leachate flows from the Central Area differ significantly from
what EPA and Ecology have determined is reasonable, EPA and Ecology may impose further
requirements in order to reduce leachate generation at the Central Area. Monitoring results were to be
reported monthly. In 2005, the City re-installed meters in the leachate collection, leachate detection, and
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surface water discharge pipes. A Hydrologic Evaluation of Landfill Performance (HELP) model was also
developed to estimate the amount of generation. Data collected generally agreed with the HELP model
results indicating that there is no significant loss of water in the Central Area. Monitoring has been
completed as required; however, there were numerous issues with the meter and data logger installed in
the leachate collection manhole due to the harsh physical environment. The City frequently made repairs
and replaced parts, but monitoring equipment was not able to continuously collect leachate generation
data. The EPA and Ecology required continued monitoring of the Central Area leachate generation as part
of the third five-year extension approval. Following the final closure of the Central Area in 2013, the
Leachate and Condensate Management Plan should be updated to reflect the current conditions and future
monitoring requirements.
On April 15, 1994, the City received a letter from Ecology's Water Quality Program which oversees the
City's pretreatment program. Upon their review of the leachate and condensate flow and pollutant data,
they determined that the Tacoma Landfill leachate and condensate effluent did not require permitting as a
Significant Industrial User (SIU) under the City's pretreatment program. The de-designation was based
upon low flow rate and analysis done to date on samples of combined effluent discharge to the sanitary
sewer. The letter indicated the City could de-designate the effluent; however, the restrictions of the
pretreatment program could not be taken as an exclusion or waiver of program requirements.
Cap Maintenance/Construction
Cap maintenance activities completed in the last five years include the West 1 Area Cap Repair, East Cap
Extension project, and repairs due to a water line break. The West 1 Area Cap Repair and East Cap
Extension project conducted in 2007-2008 replaced an area of cap due to settlement, and extended the
landfill cap on the east side of the landfill due to refuse that was found outside the limits.. In 2007, a water
line break on the western side of the landfill washed out a section of the landfill cap. This section of cap
was repaired in 2008.
Additional construction activities include filling the Central Area to grade and installation of the cover. A
GCL and HDPE cap was installed over the Central Area in several phases. The southern 15 acres were
capped in 2011, an additional 7 acres were capped in 2013, and the final 8 acres were capped in 2013.
3.4.5.3 Landfill Gas Management
Monitoring of the gas extraction wells, monitoring probes, and flare is conducted according to the 1999
Landfill Gas Management Plan, as updated in 2009.
Gas Extraction Wells
There are more than 300 gas extraction wells in operation around the perimeter and within the interior of
the landfill. Inspection of the gas collection header system is conducted on a regular basis and the overall
system is inspected daily. At a minimum, each well is monitored and adjusted twice per year to account
for seasonal fluctuations. Testing at each well includes:
• Percent methane by volume
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• Percent oxygen by volume
• Percent carbon dioxide by volume
• Pressure in inches water column (positive or negative)
• Gas temperature in degrees Fahrenheit
• Flow velocity in feet per minute and in standard cubic feet per minute
The system was designed to meet State of Washington Criteria for Municipal Solid Waste Landfills
which require that methane concentrations must not exceed the lower explosive limit (LEL), 5% methane
by volume, at the property boundary of a landfill and must not exceed 100 parts per million (ppm) in off-
site structures. A landfill gas management system is dynamic and affected by changes in the barometric
pressure, pressure changes created by the development of landfill gas within the landfill, and the vacuum
applied by the gas collection system. Because of the dynamic nature of the system, some fluctuations of
both the pressure and methane readings at the probe stations are normal. It is from these fluctuations that
the need for an adjustment to the gas system is identified. Changes in pressure alone do not trigger
adjustments to the system, because they are generally temporary in nature and result from changes in the
barometric pressure.
In recent years, leachate ponding has been identified at some extraction wells at the south end of the
landfill. If ponded leachate covers the entire perforated interval of the extraction well, then the well will
not be able to extract gas. The City historically pumped out gas extraction wells necessary to maintain
capture on an as-needed basis. This pumping program was ended in 2008 since the City believed that the
leachate collecting in the lower extraction well completions was not impacting their ability to control gas
migration (City of Tacoma, 2008d).
An evaluation of the perimeter extraction wells was completed in 2008 to determine which wells were
broken or damaged. Figure 3-5 presents the results of the 2008 inspection. Several wells were noted to be
damaged; however, the City determined that the spatial coverage with functional wells is sufficient in
these areas and these wells will not be replaced. In the northeast portion of the landfill, near Home Depot,
several wells were suspected of having issues (PW-60, PW-61, and PW-62). Three extraction wells
installed in 2006 (HD-A, HD-B, and HD-C) replaced much of the coverage for these wells, but in order in
ensure complete capture of landfill gas, the City replaced wells PW-60 and PW-62. These wells were
initially installed in 2010; however, due to installation mistakes the wells were decommissioned and re-
installed in 2011.
Gas Monitoring Probes
The gas monitoring system includes 139 gas monitoring probe stations around the perimeter, off-site, and
near the north-end gas system. The function of the perimeter landfill-gas monitoring-probe stations is to
evaluate the effectiveness of the landfill-gas control system in controlling landfill-gas migration. The
effectiveness of the system is indicated by the presence of a vacuum and absence or reduction of gas
concentration in the soils surrounding the probes. Perimeter landfill-gas probe stations are tested once per
week. If gas concentrations exceed the LEL for methane, the monitoring frequency for that probe is
increased to daily until the readings drop below the LEL at which time weekly monitoring is resumed.
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The function of the off-site probes is to ensure that landfill gas has not migrated off-site into the
surrounding community. Off-site probes are monitored monthly. If significant gas concentrations (20% of
LEL or greater than 1% by volume) are detected in the probe, the probe is monitored daily for 30 days.
VOCs are not currently analyzed as part of the program.
Over the last several years, some probes have been damaged either by construction or by vandals,
experienced problems evacuating, or experienced water problems. Due to these issues, the City completed
an evaluation in 2008 of all probes to determine where problems were historically observed. Figure 3-6
shows the results of the evaluation. The City subsequently, in 2010, replaced two perimeter probes, PS-17
and PS-18 replaced with one probe, PS-34, to maintain the perimeter gas monitoring system. Since
landfill-gas migration has decreased significantly over the years, the City requested that off-site probe
monitoring locations be reduced to 29 and that the discontinued probes be decommissioned. EPA
approved the request in August 2009 and the off-site probes were decommissioned between November
2011 and January 2012.
Off-Site Monitoring
As described in the 1999 Landfill Gas Management Plan, off-site businesses were to be monitored
monthly, utility vaults in the area were to be monitored daily, and home monitoring was to be completed
as needed. Due to the decrease in migration of landfill gas and lack of gas detections, these monitoring
programs were discontinued in 2009. If gas probe data indicate a release from the landfill, these programs
will be reinstated.
Flare Station
The flare station is operated under a permit issued by Puget Sound Clean Air Agency (PSCAA) and is
monitored five days per week. Equipment is also inspected to ensure proper operation. The flare is
required to be sampled every three years for air emissions.
Due to the decline in combustible gas volumes a new, smaller flare was constructed and became
operational in 2010. This new system includes a new John Zinc flare, new blowers, and blower pad. The
two older Sur-Lite flare were removed and eventually one of the Perennial flares will be removed. The
remaining Perennial flare will be used as backup. Emissions testing at the new flare was completed in
December 2010 and demonstrated compliance with PSCAA requirements.
3.4.5.4 Monitoring
Groundwater monitoring is conducted according to the 1996 Groundwater Monitoring Plan, which was
updated in 2010. There are 98 groundwater monitoring wells at the site. Groundwater elevation and
analytical data are collected at 76 wells, and groundwater elevation data only are collected at 22 wells.
The well type, current purpose, and sampling frequency are shown on Figure 3-8. Background monitoring
wells are sampled semi-annually or annually, all others are sampled quarterly. In 2008, the City and
TPCHD completed a door to door survey of the residents with residential wells to verify their status. Most
of residents were later notified that sampling would be discontinued in November 2009 due to a lack of
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detected landfill constituents in their wells. A couple of exceptions were at EW-12 due to detections of
vinyl chloride at low concentrations and at EW-13 due to detections of arsenic at concentrations above the
MCL. Residential well EW-12 was decommissioned in 2010 after the residence was hooked up to Fircrest
City Water and well EW-13 is the only residential well currently being sampled. A summary of the final
residential well status as summarized from the 2008 survey is presented in Table 3-2 below.
Table 3-2. Residential Well Status
Well No.
Well Functional
Water Used
for Drinking
City of Tacoma
Sample History
2008 Survey Comments
EW-00
Yes
Yes
Aug 1991-Nov 2009
In use
EW-01
—
No
Aug 1986-Nov 1991
Unknown status
EW-02
No
No
Not sampled
No evidence that this well exists
EW-03
Decommissioned
No
Aug 1996 - Sept 1990
House demolished, no sign of well.
EW-04
No
No
Not Sampled, well dry
No one home, status not verified
EW-05
No
No
Aug 1986 - Aug 1995
Believed to be on City water
EW-06
No
No
Not sampled
No one home, status not verified
EW-07
Yes
Yes
Aug 1986 - Jun 1987
In use
EW-08
Yes
No
Mar 1985 -Oct 1988
Connected to City water, well used
for irrigation.
EW-09
Decommissioned
No
Mar 1985-Nov 2009
Not used, located on a low area of
the lot susceptible to surface water
runoff. Decommissioned 2010.
EW-10
Yes
Yes
Aug 1984-Nov 2009
In use
EW-11
—
No
Mar 1985 - Oct 1988
Unknown status
EW-12
Decommissioned
No
Aug 1986-May 2010
Well covered with bricks, in use at
time of survey
EW-13
Yes
Yes
Aug 1986 - Present
Not observed
EW-14
No
No
Aug 1986 - Aug 2000
Not functional, well house
overgrown
EW-15
Decommissioned
No
Aug 1986 - May 1992
Decommissioned
EW-16
Yes
Yes
Aug 1986 - Nov 2009
In use
EW-17
Decommissioned
No
Mar 1985-Oct 1988
Decommissioned
EW-18
—
No
Mar 1985 - Aug 2003
Unknown status, but City water
meter observed.
EW-19
Yes
Yes
Nov 1994 - Nov 2009
In use
EW-20
No
No
Nov 1994 - Nov 2006
Not functional
EW-21
Yes
Yes
Nov 1994 - Nov 2009
In use
EW-22
Yes
Yes
Nov 1994-Dec 1995
Well used for drinking water,
hookup from City of Fircrest used
for irrigation.
EW-23
Decommissioned
No
Jun 1985
Decommissioned, connected to
City water
EW-24
Yes
Yes
Feb 1994-Nov 2009
In use
EW-25
Yes
No
Nov 1994-Nov 2009
Connected to City water in 1989,
unknown if used for irrigation
EW-26
Decommissioned
No
May 1988 - May 1990
New duplex on property,
decommissioned Jun 1997
EW-27
Decommissioned
No
Nov 1994-May 1988
Subdivision constructed over
historical well location
EW-28
Yes
Yes
Nov 1994-Nov 2009
In use
EW-29
—
No
Aug 1992
Unknown status
EW-30
Yes
No
Nov 1994 - May 2000
Used for irrigation
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Well No.
Well Functional
Water Used
for Drinking
City of Tacoma
Sample History
2008 Survey Comments
EW-30R
Yes
Yes
Aug 2000 - Nov 2009
Installed in 2000 since other well
not producing (EW-30)
EW-31
Decommissioned
No
May 1995-May 1999
Subdivision constructed over
historical well location
EW-32
Decommissioned
No
Mar 1996 - Nov 2003
Subdivision constructed over
historical well location
Surface water sampling is detailed in the 1990 Surface Water Sampling and Analysis Plan for the Tacoma
Landfill Remedial Design/Remedial Action. Surface water sampling at Leach Creek is conducted semi-
annually to evaluate potential impacts to the creek. The Fircrest water supply well FW-05 was sampled
monthly by the City of Tacoma until November 2009. At that time, the City met with Fircrest Public
Works and decided that the City will sample FW-05 one every three years until 2019 and Fircrest Public
Works will sample the well annually. The City continues to sample monitoring wells up-gradient of the
Fircrest well field on a quarterly basis (TL-01, TL-02, and W-22).
Following the reduction in GETS pumping in 2010, a Rebound Monitoring Plan (Landau 2010) was
developed to provide procedures for evaluating containment and actions to be taken if there is indication
of loss of containment. For the purposes of the plan, containment was defined quantitatively in terms of
groundwater quality measured at designated monitoring wells. Demonstration of containment was
evaluated using statistical procedures to assure that there is not a significant increase in concentrations.
Sixty-four monitoring wells were evaluated using the following procedures developed in the Rebound
Monitoring Plan. Results of the rebound analysis are reported annually.
1) Develop contingent action criteria using historical data based on methods described in EPA's
Statistical Analysis of Groundwater Monitoring Data at Resource Conservation and Recovery Act
(RCRA) Facilities Unified Guidance (EPA 530-R-09-007).
2) Compare post-shutdown sampling results to contingent action criteria.
3) If a contingent criterion was exceeded, re-sample to confirm the initial sampling results.
4) If an exceedance is confirmed, complete one of the three levels of response:
• Level 1 - Increase extraction rates of one of the remaining operational extraction wells or turn on an
existing extraction well.
• Level 2 - Install additional extraction wells.
• Level 3 - Add active or passive remediation actions that do not include groundwater extraction and
treatment.
As part of the update to the Groundwater Monitoring Plan in 2010, the analyte list was reduced to those
VOCs that are useful for evaluating rebound. Ethylbenzene, methylene chloride, toluene, and total
xylenes were removed from the analyte list. Landfill-indicators parameters COD, nitrate+nitrite,
ammonia, sulfide, and sulfate were also removed from the analyte list. These were historically used to
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evaluate redox conditions in the aquifer and long-term changes in groundwater quality. The current
analyte list is presented in Figure 3-9.
3.4.5.5 Summary of Costs of System Operations/O&M Effectiveness
No operations and maintenance costs were available for the Tacoma Landfill OU.
3.5. Progress Since the Last Five-Year Review
3.5.1. Protectiveness statements from last review
The protectiveness statement in the last Five-Year Review (2008) stated:
A protectiveness determination of the remedy at the Tacoma Landfill cannot be made at this time
until further information is obtained. An evaluation of impacts from the remaining groundwater
plumes to Leach Creek and migration west of the creek is required. Surface water and GETS
effluent discharge data need to be evaluated against more current surface water criteria and
reporting limits should be lowered as applicable. Concentrations of COCs in two residential
wells not connected to municipal water supply exceed the performance criteria. Pending a site
visit to determine status of these wells, additional actions may be required at these homes.
Finally, additional evaluations on the effects of elevated arsenic concentrations on human health
and the groundwater to indoor air pathway are required. It is expected that these actions will
take one year to complete, at which time a protectiveness determination can be made (between
August and December 2009). Details of project completion dates are presented in Table 3-3.
3.5.2. Status of recommendations and follow-up actions from last review
Recommendation 1: Continue to monitor gas probes at Home Depot for another year to evaluate
effectiveness of extraction wells in reducing gas concentrations.
Status: Completed. Monitoring continues at the gas probes adjacent to Home Depot. Gas extraction
wells PW-60 and PW-62, located near the Home Depot were replaced in 2011 to ensure full capture of
landfill gas in this area.
Recommendation 2: Determine which landfill gas probes are critical for monitoring and replace/repair
broken gas probes, as required.
Status: Completed. An evaluation of the gas monitoring probes and perimeter gas extraction wells was
completed in 2008 and recommendations were provided in a memorandum (City of Tacoma, 2009f). Two
damaged probes were replaced and 23 off-site probes were decommissioned due to no measurable gas
concentrations in the last 10 years.
Recommendation 3: EPA/Ecology to determine if SPS-13 is critical for monitoring and provide
recommendation for abandonment to the City.
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Status: Completed. Gas probe SPS-13 had low detections of gas over the last 10 years, but was not
critical for monitoring gas migration from the landfill. Adequate gas monitoring stations are located at the
perimeter of the landfill to detect gas migration from the landfill. EPA/Ecology approved the request to
decommission SPS-13. After further inspection, it was determined that the SPS-13 monitoring location
has two separate vaults. One contained landfill gas monitoring probes and one contained a landfill-gas
monitoring probe and groundwater monitoring well. The one containing only landfill-gas monitoring
probes was decommissioned; the other remains operational due to the presence of the groundwater
monitoring well.
Recommendation 4: Develop sampling approach for additional surface water and groundwater data for
the vinyl chloride and 1,2- DCA plumes near point of discharge (Leach Creek) and west of the Creek (see
above text for recommended requirements). Conduct sampling, as required.
Status: Completed. The City hired a consultant, Floyd|Snider, to evaluate the sampling approach near
Leach Creek. Floyd|Snider evaluated what standards were appropriate to monitor (e.g. pH, dissolved
oxygen, etc.) and the hydrogeology of the Leach Creek basin. They determined that the current sampling
program is sufficient to monitor potential comtaminant migration of the residual vinyl chloride and 1,2-
DCA plumes in the Leach Creek area.
Recommendation 5: Reduce reporting limits for surface water and effluent samples to below the new
surface water quality criteria.
Status: Completed. In the process of working with EPA and Ecology on technical issues raised in the
Third Five-Year Review, the City's laboratory attempted to decrease their reporting limit and their method
detection limit to at or below 0.02 microgram per liter ((.ig/L). A careful review of their performance over
the past year indicated that the laboratory was able to consistently quantify vinyl chloride in clean water
to 0.2 (ig/L. However, as they reached for lower detection limits of 0.02 to 0.03 (ig/L, a chronic
background level of vinyl chloride was detected in field samples, blanks, and lab control samples. It is not
completely clear whether the background levels of 0.02 to 0.03 j^ig/L represent low levels of
contamination throughout the process or signal-to-noise issues at the low levels. Since selective ion
monitoring is needed to obtain these low detection limits, it is difficult to tease these two limiting factors
apart. Based on this, the City recommended to EPA and Ecology that the laboratory uses a reporting level
of 0.2 (ig/L for aqueous samples from the Tacoma Landfill. EPA and Ecology agreed verbally to this
request. This information was documented in a February 2009 technical memorandum (Floyd|Snider,
2009a).
Recommendation 6: Evaluate GETS effluent at point of discharge and surface water samples against
newer surface water criteria, including WAC 173-201 and human health criteria, to determine if
modifications to discharge and/or sampling are required. Modifications to the decision document may be
required.
Status: Completed. After reviewing the water-use regulations for waters affected by discharges from the
Tacoma Landfill, the City presented the Leach Creek closure information to EPA and Ecology and
requested that the standard for vinyl chloride remain at 2.0 (ig/L—in compliance with the MCL (a default
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groundwater standard under Superfund) and the non-drinking water National Recommended Water
Quality Criteria (NRWQC). The EPA and Ecology verbally concurred with the recommendation but
asked for the appropriate documentation for their files. A February 2009 technical memorandum was
developed to summarize the issue (Floyd|Snider, 2009a). Because the proposed 0.025 j^ig/L water quality
standard for vinyl chloride was determined to not be appropriate for Leach Creek, the GETS standard
remains at 2.0 (ig/L. No changes to the system were required and no changes to the sampling and analysis
program at the Tacoma Landfill were needed.
Recommendation 7: Verify status of residential wells - to be conducted by the City in coordination with
Tacoma Pierce County Health Department.
Status: Completed. The City of Tacoma and TPCHD completed a door to door survey to verify the
status of residential wells in 2008 to determine which wells were or were no longer in use. With the EPA
and Ecology concurrence, the City notified residences with private wells where data indicate that there
have been no landfill impacts that their well will no longer be sampled after November 2009.
Recommendation 8: Address exceedances of vinyl chloride and arsenic at well EW-12 and arsenic at
well EW-10 pending determinations of well-use status. If in use, determine need to connect residences to
municipal drinking water.
Status: Completed. Vinyl chloride concentrations were detected at low concentrations in well EW-12; all
have been below the MCL. Well EW-12 is located across Leach Creek near the residual vinyl chloride
plume. EOP extraction well W-36 is located nearby, although it is screened at a lower depth than EW-12.
EPA and Ecology strongly recommended that the residence be put on the public water supply to remove
any potential exposure pathways. In 2010, the City connected the residence to Fircrest Water and
decommissioned the well.
The 2009 arsenic evaluation (Floyd|Snider, 2009c) determined that the residential wells with arsenic
concentrations above 10 j^ig/L were located outside the groundwater plume boundary and that these wells
were not impacted by historical contaminant releases from the landfill. In addition, it was determined that
the new 10 (ig/L arsenic MCL is not applicable to private drinking water wells and is not applicable as a
cleanup level in areas where it is less than background. Sampling at well EW-10 was discontinued in
November 2009.
Recommendation 9: Determine if arsenic is site-related or if reducing conditions from the Landfill are
causing mobilization. Evaluate effects of elevated arsenic on the human health pathway.
Status: Completed. An evaluation of arsenic was completed in 2009 (Floyd| Snider, 2009c). Long-term
groundwater monitoring results show arsenic concentrations were and remain less than 10 (ig/L in most
down-gradient monitoring wells. The generally low arsenic concentrations in the down-gradient wells
reflect natural conditions and suggest that landfill leachate has not significantly impacted groundwater
geochemistry in this area. This indicates the redox conditions which caused arsenic dissolution from
aquifer soils, prior to cap installation, were mainly limited to the Landfill Boundary Area. Arsenic halos
with limited areal extent around landfills are well documented. Slightly elevated groundwater arsenic
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concentrations in monitoring wells to the southwest of the landfill and near Leach Creek resulted from
organic-rich wetland soils and/or well completions in oxygen-poor deeper aquifers. Groundwater in these
areas was not impacted by migration of landfill leachate.
Recommendation 10: Complete a groundwater model to evaluate the effects of increased pumping of
City wells.
Status: Completed. At the time of the last FYR, the City of Tacoma was expecting to increase their use
of production wells with full use of the City's water rights within about 25 years. Since then, a second
water supply line from the Green River was activated and additional capacity was added to Howard
Hanson Dam leading to a decrease in well production. Well production rates are anticipated to remain
below average for the next several years. Additional predictive groundwater model simulations were
completed to evaluate the impact of increased pumping, if required. The models indicate that the
groundwater divide would likely shift beneath the southeast boundary of the Tacoma Landfill under the
City's current production rates with the EOP and POC wells removed and that progressively higher
production rates would shift the divide further westward towards Leach Creek (City of Tacoma, 2008c).
This would cause any remaining groundwater contamination from the landfill to flow toward the east,
rather than toward the west as it currently flows.
Recommendation 11: Evaluate the potential for a completed groundwater to indoor air pathway.
Status: Completed. To determine if a potential risk exists for vapor intrusion to impact indoor air
quality, the Johnson and Ettinger (J&E) Model was used as a screening tool to determine if vinyl chloride
and 1,2- DCA were present in high enough concentrations to cause a potential vapor intrusion risk.
Results indicate that the residual off-site concentrations do not pose a risk to residents in the area. This
analysis and results were documented in a technical memorandum by Floyd|Snider in 2009 (Floyd|Snider,
2009b). Depending on the accuracy of the City's survey of the types of building foundations and location
relative to the residual contaminant plumes, the EPA and Ecology concurred that there was very little risk
of vapor intrusion.
Recommendation 12: EPA/Ecology to provide recommendations for modifications to extraction well
operation and well sampling.
Status: Completed. EPA/Ecology approved the City's request to shut down most of the GETS extraction
wells on February 11, 2010. The approval was contingent on the following conditions: development of a
statistical approach to determine if rebound has occurred; compilation of a full inventory and status
update of groundwater monitoring wells and extraction wells; and development of data quality objectives
for each contaminant, development of contingent action criteria, modifications to the sampling program,
and submittal of quarterly monitoring data. The City shut down all of the extraction wells in March 2010,
except W-l, W-2, W-4, W-14, and W-15 which remain in operation. The City also submitted a Rebound
Monitoring Plan in 2010 (Landau 2010) that described the statistical methods for evaluation rebound.
Recommendation 13: EPA/Ecology to approve the Final Closure Plan. Request due from the City no
later than on January 31, 2009 (based on 2/24/05 authorization of the second Closure Extension).
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Status: Completed. The Third Five-Year Closure Extension was submitted to EPA and Ecology on
February 27, 2009. An amendment to the report was submitted on June 8, 2009. EPA conditionally
approved the extension on December 21, 2009 (modifications approved on July 28, 2010) with the
following provisions: bring the southern half of the Central Area to partial closure by 2011 and the
northern portion by 2012; continue Central Area flow metering for leachate and precipitation; comply
with all terms of the annual Solid Waste Permit; update the Groundwater Management Plan; update the
Landfill's IC Plan and Land Use Plan; and close the Central Area no later than December 31, 2013.
3.6. Five- Year Re view Process
3.6.1. Administrative Components
The City of Tacoma was notified of the initiation of the Five-Year Review in January 2013. The Five-
Year Review team was led by Kris Flint of EPA, Remedial Project Manager, and included Kristen Kerns
(Physical Scientist) and Sharon Gelinas (Hydrogeologist) of the USACE Seattle District.
From January to June 2013, the review team established the review schedule whose components included:
• Community Involvement;
• Document Review;
• Data Review;
• Site Inspection;
• Local Interviews; and
• Five-Year Review Report Development and Review.
3.6.2. Community Involvement
Activities to involve the community in the FYR included a notice to run in the Tacoma News Tribune
local newspaper on April 25, 2013 that a FYR was to be conducted. No comments have been received by
the community on this review.
A Fact Sheet was prepared describing the City's Third Five Year Closure Extension Request. EPA made
the request available for public comment from October 26 through November 25, 2009. No comments
were received.
3.6.3. Document review
This FYR included a review of relevant, site related documents including groundwater monitoring data,
gas extraction data, annual inspection reports, and applicable cleanup standards as listed in the 1988 ROD
and Consent Decree. A complete list of the documents reviewed can be found in Appendix A.
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3.6.4.
Data Review
3.6.4.1 GETS Effluent Monitoring
The City collects quarterly effluent samples from the GETS at several locations prior to discharge to
Leach Creek to verify that discharge criteria are being met. Historically, samples were collected from the
catch basin, which was the last sampling point before effluent leaves the site; however, construction of a
storm water pond in the northwest corner of the site required this location to be moved. The GETS outfall
is also sampled which is the last sampling point before entry into Leach Creek. Since effluent is
discharged to Leach Creek, the ROD states that the effluent must meet the MCL or chronic fresh water
criteria, whichever is more stringent. Concentrations ofVOCs (tetrachloroethene [PCE], trichloroethene
[TCE], total 1,2-dichloroethene [DCE], and vinyl chloride) in the GETS effluent increased slightly after
the majority of the extraction wells were shut down in 2010 because there was less dilution; however, all
concentrations have been below ROD-specifled criteria.
3.6.4.2 Landfill Gas Monitoring
A Home Depot store was constructed adjacent to and north of the landfill in 2000. At that time several
soil gas probes were replaced. One of the newly constructed gas monitoring wells located in the Home
Depot parking lot had detections of methane gas in excess of the LEL. The Home Depot store was
reportedly constructed on old fill material not related to the Tacoma Landfill. Investigations by the City
and TPCHD confirmed elevated levels of methane gas on the Home Depot property; however, the early
investigations did not determine whether the methane was coming from the Landfill or the fill material
that underlies the site. One sampling event conducted by the City inside the Home Depot building
indicated that methane gas was either not detected or detected at levels well below standards. Even
though the origin of the methane at Home Depot was not established, the City of Tacoma agreed to take
actions to reduce the potential for landfill gas to migrate to the Home Depot property.
Concentrations of methane in excess of the LEL continue to be detected at gas monitoring probes HD and
HD-A, located on the Home Depot property to the north of the Landfill. Probe HD has the most
consistent detections of methane in the red (shallow level) and yellow (mid level) completions at
concentrations ranging from 0 up to 25 percent methane by volume. In 2011, gas extraction wells PW-60
and PW-62 were replaced to ensure capture is maintained in the north end of the landfill. Since these
wells were replaced, methane detections have gone down. During the second half of 2012, concentrations
of methane at HD-A were mostly zero and concentrations at HD had gone down, although there were still
exceedances of the LEL for more than 5 consecutive days. Optimization of gas extraction in this area
should continue until concentrations remain below the LEL.
Sporadic detections of methane above the LEL have been detected at perimeter monitoring probes. These
types of detections are typically a result of normal system fluctuations. With the exception of probe SPS-
17A, there were no methane detections in exceedance of the LEL in off-site probes. SPS-17A had
methane readings in excess of the LEL for more than five consecutive days during the first half of 2008;
concentrations have remained below the LEL since that time.
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Several probes continue to have problems with evacuation during sampling. This can be caused by
flooding in the area of the probe station or by individual probes being constructed through saturated soil
zones. Probes that continually had evacuation problems or were damaged were evaluated by the City in
2008. Two of the damaged probes were identified to be in critical monitoring areas and were replaced.
The remainder had no action proposed and continue to have evacuation problems. It is recommended that
the City continue to periodically evaluate gas probe conditions in critical areas, such as near the Orchard
Terrace apartments that were constructed adjacent to the landfill.
3.6.4.3 Landfill Cover Monitoring
The annual inspections of physical cap integrity from 2008 to 2012 found the asphalt cap and landfill cap
to be in generally good condition. The asphalt cap meets the minimum permeability requirements, as
determined through annual pan-lysimeter observations. Several cracks and abrasions were noted on the
cap, all superficial in nature, and were either repaired or monitored depending on the severity. Subsidence
has been observed in several areas and repaired as needed. The retaining wall around the transfer station
was checked on a daily basis and measurements were taken at each joint on a monthly basis to monitor
for movement. No significant changes in expansion joints were observed from previous years.
The landfill cap previously had several areas of sparse protective vegetation. Those areas were slowly
reseeded by adjacent vegetation. Affected areas are hydroseeded if erosion is observed. The perennial
noxious weed Scotch Broom was present on the landfill and subsequently removed and sprayed to control
future growth. Subsidence of the landfill cap was observed in several areas, but does not exceed the
allowable strain limit of one percent. Ponding on the landfill cap was observed during the winter after
periods of heavy rain, particularly at the southern and northeastern areas. In the 2010, 2011, and 2012
annual reports, ponding was also observed in other areas of the landfill cap. Ponded water is either
pumped off the cap or evaporated within a few days. Since ponding and subsidence on the landfill cap
continues to be an ongoing issue, it is recommended that areas with significant water ponding be regraded
and the 1992 Operations and Maintenance Plan for the Landfill Cap, Condensate Collection System and
Central Area Leachate Collection System be updated to include procedures or criteria for cap repairs to
control this problem.
Leachate and precipitation runoff data collected indicated that the Central Area linear and leachate
collection and detection systems performed in accordance with design expections. Annual analytical
monitoring data for leachate and condensate was also reviewed. Monitoring results showed that
concentrations exceeded the ROD performance levels for 1,2-DCA, arsenic, and methylene chloride for
the condensate and combined effluent. Since all condensate is processed by the City's wastewater
treatment system before being discharged, these exceedances do not impact the protectiveness of the
remedy at the site.
3.6.4.4 Groundwater Monitoring
Concentrations of COCs in groundwater have been decreasing over time. Groundwater monitoring data
over the last five years were reviewed and compared to the ROD-specified groundwater criteria.
Exceedances of the ROD criteria over the last five years were limited to the following constituents at the
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following wells: PCE at TL-11A and W-03; TCE and 1,2-DCA at TL-04 and TL-26A; TCE at TL-11A
and W-03; and vinyl chloride at W-15, W-16, and W-36. In 2012 only TL-11A had any exceedances of
the performance levels required by the ROD: PCE at 8.4 (ig/L in November 2012 and TCE at 12 (ig/L in
November 2012. Well TL-11A is located near the southwestern corner of the landfill where extraction
wells W-l, W-2, and W-4 remain in operation.
Historically, two lobes of the groundwater plume existed at the site: the north area vinyl chloride plume
and the south area 1,2-DCA plume. The north area plume was defined by wells W-15, TL-10A, TL-7A,
and W-36. Concentrations of vinyl chloride at these wells are currently below the ROD performance
standard of 2 (ig/L. The south area plume was defined by wells W-l through W-5, TL-11A, TL-26A, TL-
9A, and PW-3/4. Concentrations of 1,2-DCA at these wells are currently below the ROD performance
standard of 5 (ig/L. Extraction wells W-l, W-2, and W-4 in the south area and W-15 and W-16 in the
north area remain in operation to ensure that contamination associated with these historical plumes is
controlled.
3.6.4.5 Rebound Monitoring
The rebound monitoring plan was designed to evaluate containment following shutdown of the majority
of the extraction wells at the Tacoma Landfill. The plan contains contingent action criteria for each
extraction/monitoring well for the nine primary contaminants: 1,1,1-trichloroethane (TCA); 1,1-DCA;
1,2-DCA; total 1,2-DCE; benzene; chloroethane; PCE; TCE; and vinyl chloride. This is a reduced COC
list to focus on those VOCs that are useful for evaluating rebound. The contingent action criteria were
based on historical data collected prior to the shutdown. Three methods were developed based on the
number of detections within the historical dataset:
• If historical data are 100% non-detections, the contingent action criterion will be set at the historical
detection limit. If an analyte was not detected in the 2 years prior to the development of criteria, the
historical data set was considered to be 100% non-detect.
• If the historical data are more than 50% non-detections, the contingent action criterion will be
calculated using a non-parametric prediction limit, which is typically set at the maximum value of the
historical data set for a confidence level of 90 to 99%. Prior to calculation of the maximum value, the
dataset was tested for outliers, which were then removed.
• If the historical data are less than or equal to 50% non-detections, the contingent action criterion will
be calculated using a Shewhart-CUSUM control chart.
An exceedance of a contingent action criteria may indicate a lack of containment and requires
implementation of procedures outlined in the Rebound Monitoring Plan. These procedures include
include resampling for verification and contingent actions. In Appendix 3-E, Table E-l presents the
contingent action criteria exceedances for samples collected between Q2 2010 and Q4 2012, after the
majority of the GETS wells were shut down. The data show that there have been numerous exceedances
of the rebound criteria since the GETS was shutdown, indicating that there has been a shift in
concentration levels. However, many of these exceedances are considered "minor," such as a slight
exceedance of a criteria that was developed based on the reporting limit. According to the rebound
monitoring plan, an exceedance of the contingent action criterion required re-sampling and then a
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response if the exceedance was verified. There was no indication of re-sampling or response actions in
any of the documents reviewed.
In order to determine the significance of these contingent action criteria exceedances, a brief data
exploration was completed. Those wells that had an exceedance were analyzed for trend using the Mann-
Kendall test for trend. The results of the analysis are presented in Appendix 3-E, Table E-2. The data
show that wells PW-01, W-l 1, and W-16 had a "probably increasing" trend; however, concentrations
were well below the ROD performance level of 5 (ig/L, ranging from 0.5 to 2 j^ig/L. A review of the time
versus data plots for those wells with exceedances of the contingent action criteria show an increase in
concentrations of PCE, TCE, 1,1-DCA, and vinyl chloride in August and November 2011, but
concentrations have since decreased (see graphs in Appendix E). This brief data exploration indicates that
there has not been a significant loss of containment at the site.
The evaluation of groundwater data using the methodology presented in the Rebound Monitoring Plan
does not appear to provide the information necessary for regulators and project personnel to make
decisions on containment. Numerous exceedances of the contingent action criteria could mask issues that
arise following the shutdown of most of the GETS wells. It is recommended that the Rebound Monitoring
Plan be revised to include a statistical methodology appropriate to determine containment at the site. The
approved revised plan should be in place prior to shutdown of any additional GETS wells.
3.6.4.6 Surface Water Monitoring
Surface water samples from Leach Creek are collected semi-annually. Samples are collected just below
the holding basin at the head of Leach Creek (LC-01), at the southern end of the historical groundwater
plume near 48th St (LC-02), the furthest downstream location at 56 th St (LC-03), and near the residual,
northern vinyl chloride plume, down-gradient of well TL-07A (LC-04). Figure 3-3. Tacoma Landfill
extraction and monitoring wells.Figure 3-3. Tacoma Landfill extraction and monitoring wells, shows the
locations of LC-01 and LC-02; LC-03 and LC-04 are not depicted.
Most VOC concentrations in surface water samples were non-detect or below ROD criteria during the last
five years. Methylene chloride was the only VOC detected at levels above ROD-specified criteria.
Exceedance of ROD criteria for methylene chloride occurred in February of 2011 at locations LC-02, LC-
03, and LC-04 with concentrations of 5.7, 5.5, and 5.1 (ig/L, respectively. Methylene chloride is a
common lab contaminant and may not be indicative of contaminant migration from the landfill. LC-01
had a detection of 4 j^ig/L in February 2011, which was below the ROD criteria of 5.0 (ig/L. Toluene was
detected at all four sampling locations in February 2011 at low concentrations, ranging from 1 to 1.3
(ig/L, where historically it had been non-detect. Since toluene is no longer analyzed, per the 2010
Groundwater Monitoring Plan update, these detections cannot be verified. Revisions to the analyte list in
the 2010 Groundwater Monitoring Plan were proposed to support the efficient review of rebound
monitoring data. Since Leach Creek is a discharge point for groundwater, compliance monitoring should
include all COCs listed in the ROD.
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3.6.5. Site Inspection
The following text describes the trip report for the site visit conducted on April 2, 2013. The site
inspection checklist and photos associated with the site visit can be found in Appendices B and C,
respectively.
Sharon Gelinas (USACE), Kris Flint (EPA PRM), and Calvin Taylor (City of Tacoma) attended the site
visit. Calvin Taylor provided transportation and tour of the site. The tour began at the northern cap area
at the location of the former greenhouse pre-load project. This area provided an excellent view of the new
recycling center, with individual bays and a hazardous waste recycling area, and maintenance center. Mr.
Taylor stated that grade elevation was raised during construction of the maintenance center and several
small areas of the cap were repaired. The northern settlement basin and mothballed groundwater
treatment plant were also observed.
The tour proceeded to the newly capped Central Area. One section still needs to have vegetation placed,
which will be completed this year. All vegetation planted last year appeared in good condition as well as
the gas probes and gas extraction wells. Mr. Taylor stated that the City will be monitoring settlement of
this area using survey points. Mr. Taylor also noted that all the brass valves on the gas wells were stolen
and were replaced with plastic to avoid future vandalism.
The southern cap area was then toured. Settlement is evident in this area as observed by the piping
extensions and elevated roadway. Mr. Taylor noted that there are areas where ponding occurs, which the
City pumps out to the sanitary sewer on an as-needed basis. The remaining extraction wells in operation
(EW-1, EW-2, and EW-4) in the southern area were observed and appeared to be in good condition.
Several other areas were observed toward the end of the tour: the new gas extraction wells at the northern
edge of the site near the Home Depot property, the transfer station, the flare (recently updgraded), and the
location of the manholes where leachate is monitored and pumped out to the sanitary sewer.
The tour then proceeded off-site. The gauging station on Leach Creek was observed as well as some of
the monitoring wells and extraction wells (currently shut down) located off-site. Off-site area land use
remains residential, with areas of higher-density residences.
3.6.6. Interviews
Dave Bosch with Tacoma Pierce County Health Department and Chris Maurer with Department of
Ecology were interviewed as part of this five year review process. Both of the interviewees generally
believed that operations and monitoring at the site was going well and that no significant issues have been
encountered in the past five years. A more detailed summary of questions and responses from each of the
interviewees is provided in Appendix 3-D.
3.6.7. Institutional Controls
An implementation plan for ICs for Tacoma Landfill was completed in November 2010. The plan fulfills
the requirement under the ROD and Consent Decree to establish and implement ICs to ensure that the
integrity of the remedial actions undertaken at the landfill are maintained in order to provide short- and
long-term protection of human health and the environment. A revised plan was submitted on July 30,
2013, which EPA subsequently approved. The City has also developed a long-range plan for site use after
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closure of the Central Area cell as documented in the 1998 Land Use Plan. The long-range plan includes
continued use of a portion of the site for solid waste transfer activities and recreational use of the rest of
the site when no longer needed for remediation activities.
A summary of each IC and its status is provided in Table 3-3 below.
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Table 3-3. Institutional Controls Summary and Status
Institutional
Control
Purpose
Action Summary
Party Responsible for Action
Enforcing Party
Timing
Status
1
Place a notice on any deed, title, or other instrument of conveyance relating to
the Tacoma Landfill indicating that the site is subject to a Consent Decree. The
notice must include a reference to and a description of the Consent Decree, as
well as a statement that the Landfill has been used to manage hazardous
substances, some of which remain under the cap. The notice must also include a
statement that land use is restricted and that any actions that disturb the cap or
the containment system, including the monitoring system, will not be allowed
unless the Environmental Protection Agency and the Department of Ecology
find that such disturbance does not increase the potential hazard to human
health and the environment, or is necessary to reduce a threat to human health
and the environment. An assurance will be provided in the notice that the
restrictions and obligations set forth in the Consent Decree will be binding upon
persons who acquire any interest in the Tacoma Landfill property.
Record a Restrictive Covenant with the Pierce County Auditor's
office on the title for the Tacoma Landfill site to ensure that
remedial actions are not damaged by Site activities and to notify
future owners of the Consent Decree restrictions for use of the
property. Include the above provisions in any notice of
conveyance relating to the Tacoma Landfill property as well as
language requiring compliance with applicable institutional
controls.
City of Tacoma Solid Waste
Division staff in coordination
with the City's Real Property
Services Section of the Facilities
Management Division, and the
Legal Department.
EPA and Ecology
Restrictive Covenant
complete -filed November
11, 2001. Notice provisions
will be provided whenever
any portion of the Site is
transferred via sale or lease
to another party.
Complete and ongoing
2
In accordance with Sections 4 and 5 of the Restrictive Covenant for the Site, the
City will provide advance notice to the Environmental Protection Agency and
Department of Ecology whenever the City sells or leases any portion of the
Tacoma Landfill to a third party. The notice must also indicate whether any of
the City's obligations will be performed by the third party acquiring the real
property.
Provide sixty (60)days advance notice to EPA and Ecology
whenever the City sells or leases any portion of the Tacoma
Landfill to a third party.
City of Tacoma Solid Waste
Division staff in coordination
with the City's Legal
Department.
EPA and Ecology
In accordance with the
Restrictive Covenant the
City will provide sixty
(60) day notice to EPA and
Ecology prior to selling or
leasing any interest in the
Property.
Complete and ongoing
3
Place restrictions on the use of groundwater at the property, including a
prohibition against pumping groundwater in affected aquifers unless it's done to
monitor groundwater contamination and/or the effectiveness of the remedial
action at the landfill.
a. Public Water System Coordination Act gives exclusive
franchise to Tacoma Water and the Fircrest Water Utility in the
vicinity of the site. Unless either purveyor denies services, no
new public water systems can be installed. A new public water
system would need to be approved by the Department of Health
(DOH) or TPCHD.
No action required. Regulations
in place.
DOH or TPCHD
Not applicable. Regulations
already in place.
Complete
b. Since the area near the site is within the Urban Growth Area,
no new or replacement private wells could be installed without
the public drinking water provider (Tacoma Water or the Fircrest
Water Utility) denying service and TPCHD approving the well
location.
No action required. Regulations
in place.
TPCHD
Not applicable. Regulations
already in place.
Complete
c. Ordinances in place in the cities of Tacoma, Fircrest, and
University Place restrict well installations near the Site.
No action required. Ordinances in
place.
City of Tacoma
Not applicable. Ordinances
already in place.
Complete
d. A one-time notification to well drilling companies and utility
locating services will be provided as part of an overall public
notice related to the final Institutional Controls Plan.
City of Tacoma Solid Waste
Division.
EPA and Ecology
One-time notification to
occur within 3 months
following approval of this
Plan.
Not complete;
notification expected in
2013
4
Use best efforts to implement institutional controls on site properties outside the
City's jurisdiction including the recording of notices, plot plans, and other
similar documents and providing notice of the institutional controls to other
affected local zoning authorities or other affected governmental entities.
a. Provide a copy of the IC Plan to the City's Building and Land
Use Services (BLUS) Division along with training to permit
staff. A layer will be added to the City's govME website
showing the location of the restrictions. This website is used by
both the City permit staff and by the public.
City of Tacoma Solid Waste
Division in coordination with the
City's BLUS Division.
City of Tacoma
BLUS Division
6 months following approval
of this plan.
Not Complete; delivery
of final IC plan
expected in 2013
b. Provide copies of the City's IC Plan and maps showing the
location of the restrictions to the cities of Fircrest and University
Place.
City of Tacoma Solid Waste
Division.
Cities of Fircrest
and University
Place
3 months following approval
of this plan.
Complete
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3.7. Technical Assessment
3.7.1. Question A: Is the remedy functioning as intended by the decision
documents?
Yes. The GETS has effectively managed contaminant migration and most of the extraction wells have
met the ROD performance levels and have been shut down. Only five extraction wells remain in
operation in areas of the historical north and south residual plumes. The landfill gas extraction system is
controlling migration of landfill gas. Elevated methane concentrations are still present near the north end
of the landfill and the Home Depot property; however, new gas extraction wells have been installed in
this area and operation is being optimized to reduce concentrations. Final closure of the Central Area will
be completed by December 31, 2013, and will complete source control measures at the site. ICs are in
place to assure that the remedial action will continue to protect human health and the environment.
Remedial Action Performance
The majority of the GETS extraction wells were shut down in March 2010. Extraction wells W-l, W-2
and W-4 near the historical south plume and W-15 and W-16 near the historical north plume remain in
operation. Monitoring of all residential wells, except EW-13, was discontinued in 2009/2010 since data
indicated that there were no impacts from the landfill. Rebound monitoring data indicate that there was a
slight increase in concentrations in 2011, but concentrations have since decreased. In 2012, PCE and TCE
at TL-11A were the only constituents that exceeded the ROD performance levels.
The landfill-gas system continues to control migration of landfill gas. Sporadic detections of methane
concentrations above the LEL were observed at the perimeter monitoring probes; however, this is typical
of normal system fluctuations. Concentrations of methane in excess of the LEL remain near the Home
Depot property at the north end of the Landfill.
The final closure extension for the Central Area was approved by the EPA and Ecology in 2009. The
Central Area has been filled to grade and the final cover will be complete by December 31, 2013.
System Operations/O&M
Extraction wells in operation are regularly monitored for pumping rates and water elevations. Extraction
rates continue to gradually decline over time due to iron bacteria precipitation in the wells. The City
periodically rehabilitates the wells using the carbon dioxide freezing method. Extraction well W-l was
replaced in 2009 due to ongoing maintenance problems. GETS effluent, which is discharged to the Leach
Creek holding basin, continues to meet discharge criteria.
An evaluation of evacuation problems or damage at landfill gas extraction wells and monitoring probes
was completed in 2008. Two extraction wells, PW-60 and PW-62, which were not fully operational were
replaced in 2011 to ensure capture of landfill gas in the northern area near the Home Depot property.
Methane concentrations have been reduced since their replacement; however, there are still periods of
elevated methane concentrations. The evaluation of perimeter and off-site monitoring probes resulted in
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the replacement of two perimeter monitoring probes and decommissioning of 23 off-site probes due to no
measurable gas concentrations in the last 10 years.
Monitoring of the landfill cap and the asphalt cap is regularly completed. Subsidence of the landfill cap
has occurred, but has not exceeded the allowable strain limit. Water frequently ponds on the cap after
heavy winter rains and is either pumped off the by cap or allowed to evaporate. Leachate and precipitation
flow data at the Central Area continue to be monitored and reported monthly to ensure that the there is no
significant loss of water from the Central Area; however, there have been numerous issues with the meter
and data logger installed in the leachate collection manhole due to the harsh physical environment.
Opportunities for Optimization
Methane concentrations above the LEL continue to be detected near the Home Depot property at the
northern end of the landfill. Operation optimization of the gas extraction wells in this area should
continue in order to reduce/control gas migration.
Final closure of the Central Area will be complete in 2013. Following this event, the Operations and
Maintenance Plan for the Landfill Cap, Condensate Collection System and Central Area Leachate
Collection System and the Leachate and Condensate Management Plans should be updated to reflect the
current site conditions. Items to consider in the revision include procedures or criteria for repair of
ponding problems and evaluation of the leachate and precipitation runoff monitoring requirements.
Following the reduction in GETS extraction, a Rebound Monitoring Plan was developed to provide
procedures for evaluating containment and actions to be taken if there is indication of loss of containment.
An evaluation of these procedures, using groundwater data collected following the shutdown, indicate the
that the statistical methodology developed may be too restrictive and may mask potential containment
problems. In addition, the contingent response action procedures described in the plan have not been
followed. It should be noted, that although response action procedures were not followed, the
exceedences identified were minor and do not indicate significant occurrence of rebound. The Rebound
Monitoring Plan should be revised to include a statistical methodology appropriate for site conditions.
This plan should be approved and in place prior to shutdown of any additional GETS wells.
The 2010 Groundwater Monitoring Plan reduced the analyte list for all sampling locations to those that
would be useful for evaluating rebound. While this may be appropriate for most of the groundwater
monitoring location, it may not be applicable to compliance monitoring locations, such as Leach Creek
surface water samples and GETS effluent samples, where the full list of ROD-established COCs should
be analyzed. The analyte lists for all samples should be reviewed and revised as necessary.
Implementation of Institutional Controls
A revised IC plan was approved by EPA in July 2013. ICs currently in place include: a restrictive
covenant filed on November 11, 2001, to ensure that the remedial actions are not damaged by site
activities and to notify future owners of the Consent Decree restrictions; restrictions on use of the
groundwater at the site through the Public Water System Coordination Act that gives exclusive franchise
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to Tacoma Water and Fircrest Water; city ordinances; and use of best efforts to provide notice of IC plan
and restrictions to properties outside the City's jurisdiction.
Early Indicators of Potential Issues
There are no indicators of potential issues.
3.7.2. Question B: Are the exposure assumptions, toxicity data, cleanup levels,
and remedial action objectives (RAOs) used at the time of the remedy
selection still valid?
Yes. Despite updates to several toxicity parameters for multiple chemicals, the performance levels still
meet an acceptable level of risk at the site.
Changes in Standards and TBCs
A review was done to identify any changes in standards that were identified as applicable or relevant and
appropriate requirements (ARARs) in the ROD; newly promulgated standards including revised
chemical-specific requirements (such as MCLs); revised action- and location-specific requirements; and
State standards and to-be-considered criteria (TBCs) identified in the ROD that bear on the protectiveness
of the remedy. Any such changes were then evaluated to establish whether the new requirement indicates
that the remedy is no longer protective. A summary table is presented in Table 3-4. Generally, the
standards and toxicological values used at the time of remedy selection have remained unchanged except
that the MCL for arsenic and several reference dose (RfD) values for groundwater and surface water
constituents have changed.
When the 1988 ROD was issued the arsenic MCL was 50 |ig/L: in 2002, it was reduced to 10 |ig/L.
Residences with drinking water wells that were impacted by contamination from the Landfill have been
connected to the municipal water. For the homes where residents reportedly drink municipal water, the
change in standard has no impact on protectiveness.
The MCL for TCE was 5 |ig/L when the ROD was issued in 1988 and remains unchanged. Since that
time, the toxicity factor used to estimate the excess cancer risk associated with exposure to TCE has been
revised. In September 2011, EPA completed a review of the TCE toxicity literature and posted on
Integrated Risk Information System (IRIS) both cancer and non-cancer toxicity values which resulted in
lower risk screening levels (RSLs; previously called preliminary remediation goals [PRGs]) for TCE. The
screening level for chronic exposure for cancer excess risk level of lxlO"6 is 0.44 j^ig/L. EPA uses an
excess cancer risk range between 10"4 and 10"6 for assessing potential exposures, which means a TCE
concentration between 0.44 and 44 (ig/L. The current MCL for TCE is 5 (ig/L, is within the revised
protective carcinogenic risk range. EPA's 2011 Toxicological Review for TCE also developed safe levels
that include at least a 10-fold margin of safety for health effects other than cancer. Any concentration
below the non-cancer RSL indicates that no adverse health effect from exposure is expected.
Concentrations significantly above the RSL may indicate an increased potential of non-cancer effects.
EPA's 2011 toxicity evaluation of TCE's non-cancer effects also included a subchronic outcome of fetal
cardiac malformations that may occur during exposure to the pregnant mother during a nonspecific 21-
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day period in the first trimester of pregnancy, according to the IRIS Toxicological Review for TCE.
Accordingly, EPA Region 10 recommends limiting TCE exposures for adult human females of
reproductive age so that the average dose or concentration over any 3-week period is less than or equal to
the TCE RfD or RfC. This exposure would likely be without an appreciable risk of deleterious non-cancer
effects, including non-cancer toxicity effects during development. The non-cancer screening level for
TCE is 2.6 (ig/L. As mentioned earlier in this section, Institutional controls are in place to prohibit the
use of groundwater at this site. Additionally, a deed restriction exists to prohibit the construction of a
building on this site without approval from EPA; which will ensure protectiveness for potential vapor
intrusions issues in the future.
State requirements promulgated in WAC 173-201 and chronic surface water quality criteria were used in
the ROD, in part, to evaluate discharge to Leach Creek, which is used for spawning of coho and chum
salmon, and may also include rainbow and cutthroat trout. Since the ROD, changes in both criteria have
occurred. Chronic values are no longer promulgated for several compounds, as noted in Table 3-4. The
revised WAC code has been updated to incorporate the EPA NRWQC. As presented in Table 3-4, the
values for consumption of water and fish are lower than surface water discharge criteria presented in the
Consent Decree for 1,2-DCA, vinyl chloride, and methylene chloride. Concentrations of VOCs in surface
water from Leach Creek have been detected below the cleanup level since 2003, with the exception of
methylene chloride. Reporting limits for 1,2-DCA and vinyl chloride are above the surface water quality
criteria so impacts from these changes cannot be evaluated.
Changes in Exposure Pathways
The ROD for the Tacoma Landfill site described current and future land uses accurately and identified
likely exposure pathways. The potential risk due to the intrusion of VOCs into indoor air was identified in
the previous five-year review as a potentially significant pathway that had not be previously identified. In
the August 28, 2009 memo by Floyd|Snider, it was determined that vapor intrusion is an incomplete
pathway and does not present a significant risk to human health. Use of the J&E Model to screen
groundwater concentrations for vinyl chloride and 1,2-DCA under worst-case conditions found that
residual concentrations off-site of the Tacoma Landfill do not pose a risk to residents in the area.
Changes in Toxicity and Other Contaminant Characteristics
In addition to several changes to MCL values for arsenic and TCE, several RfD values have also been
updated since the previous 5 year review. The oral RfD for 1,2-DCA was updated under MTCA in 2005
from 'no data' to 0.02mg/kg/day. The oral RfD for toluene was updated in 2008 from 0.2 to 0.8
mg/kg/day. The oral reference dose was updated in 2010 for 1,1,1-tricholoroethane from 9.0 to 2.0
mg/kg/day. Xylenes were also updated in 2005 from 2.0 to 0.2 mg/kg/day. Despite these changes, the
performance levels at the site still fall within an acceptable level of risk.
Changes in Risk Assessment Methods
There have been no substantial changes to the standardized risk assessment methods.
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Expected Progress Toward Meeting RAOs
At this time it appears the remedy at Tacoma Landfill is progressing as expected. Despite revisions that
have resulted in decreased MCL values, the site continues to see generally decreasing concentrations of
constituents over time that either meet or fall below the ROD-specified performance levels.
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Table 3-4. Changes in Chemical-Specific Standards
Contaminant* *
Media
Cleanup Level (ng/L)
Standard***
fag/L)
Citation/Year
fag/L)
Benezene
Groundwater
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Chloroethane
Groundwater
20.0
Previous
No data
Researched - no data
New
No data
Researched - no data
1,1 -Dichloroethane
Groundwater
20.0
Previous
800
MTCA Groundwater
Method B, non-
carcinogen, standard
formula value
New
1600
2008 MTCA
Groundwater Method B,
non-carcinogen, standard
formula value
1,2-Dichloroethane
Groundwater
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Ethyl Benzene
Groundwater
320.0
Previous
700.0
MCL, 1988
New
700.0
MCL, 2012
Methylene Chloride
Groundwater
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Toluene
Groundwater
175.0
Previous
1,000.0
MCL, 1988
New
1,000.0
MCL, 2012
1,U-
Trichloroethane
Groundwater
200.0
Previous
200.0
MCL, 1988
New
200.0
MCL, 2012
Xylenes
Groundwater
10.0
Previous
10,000.0
MCL, 1988
New
10,000.0
MCL, 2012
1,2-Dichloroethene*
Groundwater
70.0
Previous
72
MTCA Method B, non-
carcinogen, standard
formula value
New
72
MTCA Method B, non-
carcinogen, standard
formula value
Trichloroethene *
Groundwater
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Arsenic*
Groundwater
50.0
Previous
50
MCL, 1988
New
10
MCL, 2012
Benezene
Surface water
(fresh)
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Chloroethane
Surface water
(fresh)
20.0
Previous
No data
Researched - no data
New
No data
Researched - no data
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Contaminant* *
Media
Cleanup Level (ng/L)
Standard***
fag/L)
Citation/Year
fag/L)
1,1 -Dichloroethane
Surface water
(fresh)
20.0
Previous
800
MTCA Groundwater
Method B, non-
carcinogen, standard
formula value
New
1600
2008 MTCA
Groundwater Method B,
non-carcinogen, standard
formula value
1,2-Dichloroethane
Surface water
(fresh)
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Ethyl Benzene
Surface water
(fresh)
320.0
Previous
700.0
MCL, 1988
New
700.0
MCL, 2012
Methylene Chloride
Surface water
(fresh)
5.0
Previous
5.0
MCL, 1988
New
5.0
MCL, 2012
Toluene
Surface water
(fresh)
175.0
Previous
1,000.0
MCL, 1988
New
1,000.0
MCL, 2012
1,1,1-
Trichloroethane
Surface water
(fresh)
200.0
Previous
200.0
MCL, 1988
New
200.0
MCL, 2012
Vinyl Chloride
Surface water
(fresh)
2.0
Previous
2.0
MCL, 1988
New
2.0
MCL, 2012
Xylenes
Surface water
(fresh)
10.0
Previous
10,000.0
MCL, 1988
New
10,000.0
MCL, 2012
*Additional COCs were added as performance levels for groundwater during the Remedial Design study in 1991.
**In addition to performance standards dictated by the ROD, additional Washington State standards for active landfill operations
must be met. These standards are set forth in WAC 173-200, Water Quality Standards for Groundwaters of the State of
Washington; WAC 173-290, Drinking Water Regulations; WAC 173-304-490, Leachate Parameters; and, WAC 173-351-200,
Gas Production.
***Previous Standard is at time of the ROD. If 'NA', no standard was established at the time of the ROD. New Standard is the
most recent update post-ROD. If'—', no updates have been made to the standard.
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Table 3-5. Changes in Action-Specific Requirements
Action
Requirement
Prerequisite
Citation/Year
Landfill
Previous
Groundwater corrective action
required until concentrations of
hazardous constituents at the
point of compliance achieve
either MCLs or alternate
concentrations limits. All
hazardous wastes at a site should
be removed, treated on site, or
capped in such a way as to
minimize the migration of
contaminants from the site.
Contaminated media
contributing to groundwater
contamination is present at
the site.
Resource Conservation and
Recovery Act (RCRA, 49
CFR 261) Washington State
Dangerous Waste Regulations
and Washington State
Minimal Functional Standards
for Solid waste Handling
New
No changes that impact remedy
since last Five-Year Review.
Drinking
Water
Previous
Federal MCLs shall be met to
prevent exposure to the public to
contaminated drinking water.
Affected water supplies will be
connected to City Water.
Contaminants regulated
under federal guidelines.
Groundwater is adjacent to
drinking water sources.
Section 1412 of the Safe
Drinking Water Act (SDWA),
42 U.S.C. 300g-l, "National
Drinking Water Regulations";
National Primary Drinking
Water Regulations. 40 CFR
Part 141
New
Exposure toxicity for TCE was
revised in 2011. However, the
MCL remains unchanged and is
considered protective of both
carcinogenic and non-
carcinogenic effects.
Air
Previous
Regulates air emissions to
protect human health and the
environment associated with air
stripper (if used) and any flares
used at the site.
Original remedy specified
in the ROD required use of
air stripper for treatment of
groundwater.
Clean Air Act, 42 U.S.C.
7401
New
Air stripper not used on site.
Flares under permit. No change
that impacts remedy since last
Five-Year Review.
Surface
Water
Previous
Treatment and release of
effluent. Landfill cap will reduce
leachate generation.
The landfill produces
leachate and effluent due to
daily operations and
treatment technologies.
Clean Water Act (CWA)
Section 402 NPDES
Requirements
New
ROD specifies no permit
required for on site remedial
activities.
*Although not specified in the ROD, The City also maintains a Solid Waste Permit for the Landfill, managed by TPCHD under
the authority of RCW 70.95 and in accordance with WAC 173-351 and 173-350. Recent revisions to WAC 173-351 require
monitoring of total metals in groundwater. The previous version of the rule required the monitoring of dissolved metals in
groundwater. Tacoma Landfill has tentative plans to incorporate this new requirement into their Closure Monitoring Plan.
3.7.3. Question C: Has any other information come to light that could call into
question the protectiveness of the remedy?
No other information has come to light that could call into question the protectiveness of the remedy.
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3.7.4. Technical Assessment Summary
The GETS has been effective at managing contaminant migration and most of the extraction wells were
shut down in 2010. Five extraction wells remain in operation, two near the historical north area residual
plume and three near the historical south area residual plume. Rebound monitoring data indicate that there
was a slight increase in contaminant concentrations in 2011; however, concentrations have since
decreased. The methodology developed for monitoring containment in the 2010 Rebound Monitoring
Plan is not appropriate for site conditions and should be revised prior to shutdown of any additional
extraction wells. The reduced analyte list from the 2010 groundwater monitoring plan should also be
reviewed and revised as necessary to ensure that compliance monitoring locations, e.g. Leach Creek
surface water samples and GETS effluent samples, are analyzed for the full list of ROD COCs. The
landfill-gas system continues to control migration of landfill gas. Concentrations of methane above the
LEL are still detected near the Home Depot property at the north end of the landfill. New extraction wells
have been installed in this area and their operation is being optimized to reduce concentrations. Final
closure of the Central Area will be completed by December 31, 2013. Following this event, the
Operations and Maintenance Plan for the Landfill Cap, Condensate Collection System and Central Area
Leachate Collection System and the Leachate and Condensate Management Plans should be updated to
reflect the current site conditions. ICs are in place to assure that the remedial action will continue to
protect human health and the environment. Several toxicity parameters have been updated for multiple
chemicals. However, performance levels still meet an acceptable level of risk at the site. There have been
no changes to the exposure pathways that would impact protectiveness at the site.
3.8. Issues
Table 3-6 summaries the current issues for the Tacoma Landfill site.
Table 3-6. Issues
Issues
Affects Current
Protectiveness
(Y/N)
Affects Future
Protectiveness
(Y/N)
1. Water ponding and cap subsidence continue to occur on areas of the
landfill cap.
No
Yes
2. The Operations and Maintenance Plan for the Landfill Cap, Condensate
Collection System and Central Area Leachate Collection System and
Leachate and Condensate Management Plan may not reflect current
conditions following closure of the Central Area.
No
Yes
3. Landfill gas continues to be detected near the Home Depot Property at
the north end of the landfill.
No
Yes
4. The Rebound Monitoring Plan statistical methodology is too restrictive,
leading to numerous exceedances of the contingent action criteria, and the
response action procedures described in the plan have not been followed.
No
Yes
5. The 2010 Groundwater Monitoring Plan reduced the analyte list to those
VOCs useful for evaluating rebound. While this may be acceptable for the
rebound monitoring wells, it should not be used at locations used to
determine compliance with ROD criteria, such as Leach Creek surface
water sampling and GETS effluent samples.
No
Yes
244
South Tacoma Channel Superfund Site Five-Year Review
-------
3.9. Recommendations and Follow-up Actions
Table 3-7 provides recommendations to address the current issues at the Tacoma Landfill site, along with
proposed milestone dates to achieve the follow-up actions.
Table 3-7. Recommendations and Followup Actions
Issue
Recommendations and
Followup Actions
Party
Responsibl
Oversight
Agency
Milestone
Date
Affects Protectiveness
(Y/N)
e
Current
Future
1.
Regrade areas of the landfill
cap that continue to have
significant ponding and
subsidence.
City of
Tacoma
EPA,
Ecology,
TPCHD
September
2014
No
Yes
2.
Update the Operations and
Maintenance Plan for the
Landfill Cap, Condensate
Collection System and
Central Area Leachate
Collection System and the
Leachate and Condensate
Management Plan.
City of
Tacoma
EPA,
Ecology,
TPCHD
September
2014
No
Yes
3.
Continue operation
optimization of gas
extraction in wells on the
northern edge of the Landfill
near the Home Depot
property.
City of
Tacoma
EPA,
Ecology,
TPCHD
September
2014
No
Yes
4.
Update the Rebound
Monitoring Plan.
City of
Tacoma
EPA,
Ecology,
TPCHD
September
2014
No
Yes
5.
Update the 2010
Groundwater Monitoring
Plan to include the full list of
ROD COCs for sampling
locations used to determine
compliance (e.g. Leach
Creek and GETS effluent).
City of
Tacoma
EPA,
Ecology,
TPCHD
September
2014
No
Yes
Included below are additional recommendations to be considered that do not affect current or future
protectiveness of the remedy:
• Continue to evaluate gas-monitoring probes that have a history of evacuation problems during
sampling and replace as necessary to ensure a complete gas monitoring program is in place.
3.10. Protectiveness Statements
The remedy at the Tacoma Landfill is currently protective of human health and the environment in the
short term because the groundwater and landfill gas is being controlled through the GETS and landfill-gas
management system, the Central Area final cover will be complete by December 31, 2013, and ICs are in
OU 5/6, Tacoma Landfill
245
-------
place. However, in order for the remedy to be protective in the long term, the following actions need to be
taken to ensure protectiveness:
• Continue operation optimization of gas extraction wells at the north end of the Landfill.
• Re-grade areas of the landfill cap prone to ponding and subsidence.
• Update the following management plans to ensure the monitoring program is effective and response
action procedures are in place: Operations and Maintenance Plan for the Landfill Cap, Condensate
Collection System and Central Area Leachate Collection System; Leachate and Condensate
Management Plan; Rebound Monitoring Plan; Groundwater Monitoring Plan; and Institutional
Controls Plan.
3.11. Next Review
The next Five-Year Review for the Tacoma Landfill OU is required by September 2018, five years from
the date of this review.
246
South Tacoma Channel Superfund Site Five-Year Review
-------
Tacoma Landfill Figures
OU 5/6, Tacoma Landfill
247
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[This page is intentionally blank]
248 South Tacoma Channel Superfund Site Five-Year Review
-------
X)ALl.ENMORE
r 5
llGOCf CLUB
WTfil
Pirerest
t 11 OKI
Pit
QMEApCW FArt*
( GOL? .--Oi.RV
ySfcum
CisUr
KfliSck
ijT"* Ct <*tut
Kn»ir»
| J*rrt
StXTC
- LJiev.c-o<:
JS. C.VnifAW
Tacoma Landfill
Site Vicinity Map
Source:
USGS Topographic Map, Tacoma South, WA, 1997
USGS Topographic Map, Steilacoom, WA, 1997
Figure 3-1. Tacoma Landfill site vicinity map.
OU 5/6, Tacoma Landfill
249
-------
A
1 ¦ v- ¦ ¦ - ¦,
¦¦ ,' '&&&£>. ¦. 5 SI'S
1$hg::. • '- ¦:; ' ¦•¦-
m '
- A'iVfi ....... -¦¦¦.'¦¦¦' ;
¦ • "•; v ;v
¦v-s. • . •..
• ¦ - M *
g '.A-::
s
I
E
Landau
Associates
Scale m Feet
Vertical Exaggeration 'OX
Landfill Plume
City of Tacoma
Tacoma, Washington
Legend
|Cr*f^ Vatfion RedftSlOfial Ovpo^l
[Cm} Vaetxxt Qtadal Tilt
jfrvaj V«shon Advance Qutwash
fOog^ Pre-ptympm Gravel
ESS Pre-Oymfaa Lacustrme
$ Stfeentd interval
AppfOf.im.iW Water Lav«» Elevation
SiKy Sand (SM|
Poody Graded S»nd (Sf)
^3
P Pootfy Graded Gtavoi {GPJ
&« (ML>
i Ttrn* cws$-*0cbon has Seen interpreted and
generalized from Held data COlBCtMl fay
Landau Associates and others
South Investigation Area
Cross Section B-B'
Figure
Figure 3-2. Representative geologic cross-section.
250
South Tacoma Channel Superfund Site Five-Year Review
-------
LEGEND
Tqcomo Landfill
Monitoring Wall
{niuWpf* completion fn
on* bor»hol»)
Tacoma Landfill
Monitoring Will (alngla
completion)
Mating Drinking
Waftr W*lf
W—17 1
\MW—16—2
Tb-40,
0 Oflc D
TL~2^I ! '
W-41
oao i! aom
EW-20
a o o° d
o On a
TACOMA LANDEILL
BASEMAP
FIGURE 1-1
Figure 3-3. Tacoma Landfill extraction and monitoring wells.
OU 5/6, Tacoma Landfill
251
-------
FIGURE 1-2
SEQUENCE OF FILL
OPERATION
Figure 3-4. Tacoma Landfill sequence of fill operations.
252
South Tacoma Channel Superfund Site Five-Year Review
-------
CITY OF TACOMA - TACOMA LANDFILL
PERIMETER EXTRACTION WELLS
WITH KNOWN OR SUSPECTED ISSUES
FIGURE 3
NO ACTION AT THIS TIME
CONTINUE TO EVALUATE
WELL DATA
REPLACE WELLS
Figure 3-5. Tacoma Landfill gas extraction wells.
OU 5/6, Tacoma Landfill
253
-------
LEGEND:
REPLACE PROBES
NO ACTION AT THIS TIME
CONTINUE TO EVALUATE
CITY PROPOSING TO
STOP MONITORING
AND EVENTUALLY
Figure 3-6. Tacoma Landfill gas monitoring probes.
TYLER STREET
PSHDj
ORCHARD~STREET
254
South Tacoma Channel Superfund Site Five-Year Review
-------
TACOMA LANDFILL
EXTRACTION WELLS
CAPTURE ZONES 4th Qrtr 2008
FIGURE 3-14D
13q,c
1200
LEGEND
® EW-14 Existing Private Drinking
Water Well
GETS Extraction Well
P—3/4 GETS Performance
Monitoring Well
TL—12 Tacomo Landfill
TL—la Monitoring Well
City of Fire rest Well
Leach Creek Sampling
Location
- — — — Well Capture Zone-2007
Groundwater Conlour-2007
(Prepared by Pacific
Groundwater Group)
Pa£tMSOfVfeMtPn)«Cto^ mnWUnraJS waetJMTH CAPTL^JfMFS&J2Jlflrt«fl| Wami M
Figure 3-7. Tacoma Landfill capture zones 4th quarter 2008.
o
Dal
bn a
] 0 °
a
O
EW-
OU 5/6, Tacoma Landfill
255
-------
Table 1 Groundwater Extraction and Monitoring Wells
November 2010
Location
Well
Well Type
On-Site
or
Off-Srte
Screened
Interval (ft
bgs)
Historical Purpose
Current Purpose
Groundwater
Monrtoring
Frequency
Years Groundwater
Analytical Samples
Collected
Description/Comments
Point of
W-01
Extraction
On-Site
148-153
Groundwater Extraction and Monitonng
Groundwater Extraction and Rebound Monitonng
¦Quarterly
1896-
Continue operation Collect groundwater analytical data to support shutdown.
Compliance (POC)
W-02
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Extraction and Rebound Monitonng
Quarterly
2005-
Continue operation Collect groundwater analytical data to support shutdown
- Landfill
Boundary
W-03
Extraction
On-Site
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
5hut down May 2009 to monitor for rebound Likely screen failure Well failure had occurred
twice before. No groundwater performance standard exceedances for five years prior to
shutdown
W-04
Extraction
On-Site
148-163
Groundwater Extraction and Monitoring
Groundwater Extraction and Rebound Monitonng
Quarterly
2005-
Continue operation. Collect groundwater analytical data to support shutdown
W-05
Extraction
On-Site
145-153
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 2010.
W-06
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010
W-07
Extraction
On-Site
-
Groundwater Extraction and P/Jonitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010.
W-08
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010.
W-D9
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010
W-10
Extraction
On-Site
138-146
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 2010.
W-11
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010.
W-12
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010
W-13
Extraction
On-Site
"
Groundwater Extraction and Monitoring
N/A
N/A
1995
Shutdown February 2002. redundant well w/ poor production. One groundwater quality
analysis in 1995
W-14
Extraction
On-Site
Groundwater Extraction and Monitoring
Groundwater Rebound Monitonng
Quarterly
2005-
Shutdown in February 2010 to monitor for rebound Likely screen failure discovered dunng
rehab on 2/26/10 No groundwater performance standard exceedances five years pnor to
shutdown.
W-15
Extraction
On-Site
78.5-S6.5
Groundwater Extraction and Monitoring
Groundwater Extraction and Rebound Monitoring
Quarterly
1996-
Continue operation. Only slightly exceeds VC GWPS, downward trend in VC evident for past 5
W-10
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Extraction and Rebound Monitoring
Quarterly
2005-
Continue operation. One vinyl chloride exceedance reported since sampling began.
W-17
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
Shut down to monitor for rebound March 2010
W-18
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitonng
Quarterly
20D5-
Shut down to monitor for rebound March 2010.
W-19
Extraction
On-Site
-
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
2005-
W-19 shutdown in November 2005 to monitor for rebound. Also excessive sand in well noted
during last rehab in 2005.
W-20
Extraction
On-Site
130-145
Groundwater Extraction and Monitonng
Groundwater Rebound Monitonng
Quarterly
1997-
Shut down to monitor for rebound March 2010
W-21
Extraction
On-Site
125-140
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Shut down to monitor for rebound March 2010
W-22
Extraction
On-Site
135-150
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Shut down to monitor for rebound March 2010
Tacoma Landfill
89.5 PI
Monitoring
Off-Site
*
Groundwater Monitoring - Background
Groundwater Monitonng - Elevation Only
Quarterly
1996-
Concluded analytical sampling November 2009. Not impacted by groundwater plume
Monitoring Wells
89.5 P2
Monitoring
Off-Site
-
Groundwater Monitoring - Background
Groundwater Monitoring - Elevation Only
Quarterly
1996-
Concluded analytical sampling November 2009 Not impacted by groundwater plume
EW-13
Private Well
Off-Site
-
Groundwater Monitoring
Groundwater Monitoring
Quarterly
1985-2009
Continue analytical monitoring well Groundwater elevation not monitored at this well
FL-1A
Monitoring
On-Site
-
Groundwater Monitonng
Groundwater Monitonng - Elevation Only
Quarterly
1996
One VOC sample analysis; no impacts to groundwater This is an upgradient well
FL-1B
Monitoring
On-Site
•
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1996
One VOC sample analysis: no impacts to groundwater This is an upgradient well
LW-01
Monitoring
On-Site
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1989-1995
Sampling concluded 1995 Well located in a closed cell Long-term decreasing VOC
MW-11-1
Monitoring
On-Site
128-136
Groundwater Monitoring
Groundwater Monitonng - Elevation Only
Quarterly
N/A
Water elevations collected 1994 to present No analytical sampling conducted at this well,
MW-11-2
Monitoring
On-Site
130-135
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
N/A
Water elevations collected 1994 to present No analytical sampling conducted at this well
MW-16-2
Monitoring
On-Site
118-123
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1995
Sampled once for water quality analysis.
MW-16-3
Monitonng
On-Site
95-105
Groundwater Monitonng
N/A
N/A
N/A
Monitored water elevations only from 1994-2005, likely stopped due to poor well condition
TL-01A
Monitonng
On-Site
97-111
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1986—
Resume quarterly monitonng January 2010
TL-01B
Monitoring
On-Site
133-138
Groundwater Monitoring
Groundwater Rebcwnd Monitoring
Quarterly
1986-
Resume quarterly monitonng January 2010
TL-Q1C
Monitonng
On-Site
163-173
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1986-
Resume quarterly monitoring January 2010
TL-02A
Monitoring
Off-Site
72-92
Groundwater Monitoring
N/A
NA
1989-1996
No groundwater performance exceedances No longer monitored
TL-02C
Monitoring
Off-Site
140-145
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
198&-
Resume quarterly monitonng January 2010
TL-03A
Monitoring
Off-Site
40-50
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1989-1995
Resume sampling if drinking water detection limit exceedance occurs In TL-02C
TL-03C
Monitoring
Off-Site
105-110
Groundwater Monitonng
Groundwater Monitonng - Elevation Only
Quarterly
1989-1996
Resume sampling if dnnking water detection limit exceedance occurs m TL-02C
TL-04
Monitonng
Off-Site
91-105
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1986-
TL-05A
Monitonng
Off-Site
14-19
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1989-
TL-05C
Monitoring
Off-Site
34-38
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1989-
TL-05D
Monitoring
Off-Site
73-78
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1990-1996
No groundwater performance standard exceedances
TL-Q7A
Monitoring
Off-Site
22-29
Groundwater Monitoring
Groundwater Monitonng
Quarterly
1989-
TL-Q8A
Monitoring
On-Site
101-115
Groundwater Monitonng
Groundwater Monitonng - Elevation Only
Quarterly
1986-1995
No groundwater performance standard exceedances.
TL-08B
Monitoring
On-Site
140-145
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1986-1995
No groundwater performance standard exceedances
TL-OSC
Monitoring
On-Site
170175
Groundwater Monitoring
Groundwater Monitonng - Elevation Only
Quarterly
1986-1995
No groundwater performance standard exceedances,
TL-Q9A
Monitoring
Off-Site
52-67
Groundwater Monitoring
Groundwater Monitonng
Annually
1986-
TL-09B
Monitoring
Off-Site
100-105
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1936-
Sampled annually for analysis since 1996.
TL-10A
Monitonng
Off-Site
46-61
Groundwater Monitonng
Groundwater Rebound Monitoring
Quarterly
1987-
TL-10B
Monitonng
Off-Site
76-81
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1937-
TL-10C
Monitoring
Off-Site
98-103
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1939-
* I Wtttfttmvi**4MN* !_'l*iSi*4Er
Table t
Page 1 of 2
Figure 3-8. Tacoma Landfill monitoring well status table.
256
South Tacoma Channel Superfund Site Five-Year Review
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[This page is intentionally left blank.]
OU 5/6, Tacoma Landfill 257
-------
Table 1 Groundwater Extraction and Monitoring Wells
November 2010
Location
Well
Well Type
On-Site
or
Off-Site
Screened
Interval (ft
bgs)
Mistorical Purpose
Current Purpose
Groundwater
Monitoring
Frequency
Years Groundwatei
Analytical Samples
Collected
Description^CommentB
TL-10D
Monitoring
Off-Site
121-126
Groundwater Monitoring
N/A
N/A
N/A
No groundwater performance standard exceedances. No longer monitored .
TL-11A
Monitoring
On-Site
105-124
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1986-
Tnchloroethene and tetrachtoroelhene exceed GWPS.
TL-11B
Monitoring
On-Site
149-154
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1987-
TL-11D
Monitoring
On-Site
198-203
Groundwater Monitoring
N/A
N/A
N/A
No groundwater performance standard exceedances. No longer monitored,
TL-12
Monitoring
Off-Site
140-155
Groundwater Monitoring
On-site - Groundwater Monitoring
Annually
1937-
TL-13A
Monitoring
Off-Site
88-103
Background Monitoring
Groundwater Monitoring - Background
Semiannually
1989-
Requested annual sample frequency starting January 2011
TL-13C
Monitoring
Off-Site
147-152
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Semiannually
1989-
Requested annual sample frequency starting January 2011 1
TL-14A
Monitoring
Off-Site
81-96
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Annually
1989-
TL-15A
Monitoring
On-Site
69-83
Groundwater Monitoring - Background
Groundwater Monitoring - Elevation Only
Quarterly
1986-1395
Background well not impacted by groundwater plume. i
TL-15B
Monitoring
On-Site
113-133
Groundwater Monitoring - Background
Groundwater Monitoring - Elevation Only
Quarterly
1986-1995
Background well not impacted by groundwater plume-
TL-15C
Monitoring
On-Site
152-157
Groundwater Monitoring - Background
Groundwater Monitoring - Elevation Only
Quarterly
1986-1995
Background well not impacted by groundwater plume.
TL-16R
Monitoring
Off-Site
108-112
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Quarterly
1995-
Requested annual sample frequency starting January 2011
TL-17AR
Monitoring
Off-Site
75-90
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Quart erty
2000-
Requested annual sample frequency starting January 2011
TL-17BR
Monitoring
Off-Site
114-119
Groundwater Meditoring - Background
Groundwater Monitoring - Background
Quarterly
2000-
Requested annual sample frequency starting January 2011
TL-18A
Monitoring
Off-Site
81-96
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Annually
1989-
TL-18C
Monitoring
Off-Site
140-145
Groundwater Monitoring - Background
Groundwater Monitoring - Background
Annually
1989-
TL-19A
Monitoring
Off-Site
11-25
Groundwater Monitoring
Groundwater Monitoring
Annually
1989-
TL-19C
Monitoring
Off-Site
59-64
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1989-
TL-20A
Monitoring
Off* Site
18-33
Groundwater Monitoring
[Groundwater Monitoring - Elevation Only
Quarterly
1989-1996
No groundwater performance standard exceedances
TL-20C
Monitoring
Off-Site
73-77
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1980-
TL-21A
Monitoring
Off-Site
38-48
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1989-2010
TL-22A
Monitoring
Off-Site
85-100
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1989-
TL-23A
Monitoring
Off-Site
61-76
Groundwater Monitoring - Background
Groundwater Monitoring - Elevation Only
Quarterly
1989-2010
Well was not impacted by the groundwater plume. |
TL-24A
Monitoring
Off-Site
B2-97
Groundwater Monitoring
Groundwater Monitonng - Elevation Only
Quarterly
1989-1995
Well was not impacted by the groundwater plume,
TL-25A
Monitoring
Off-Site
59-69
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1995-
TL-25B
Monitoring
Off-Site
94-99
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1995-
TL-26A
Monitoring
Off-Site
90-100
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1995-
Long-term decreasing trend for 1,2-dichloroethane.
TL-26B
Monitoring
Off-Site
136-141
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1995-
TL-27A
Monitoring
Off-Site
91-101
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1995-
TL-27B
Monitoring
Off-Site
130-135
Groundwater Monitoring
Groundwater Rebound Monitonng
Quarterly
1995—
TL-28A
Monitoring
Off-Site
67-77
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1995-2009
No groundwater performance standard exceedances. Well not Impacted by groundwater
[End of Ptume
W-30
Extraction
Off-Site
39-49
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down August 2008 to monitor for rebound
W-31
Extraction
Off-Site
35-^50
Groundwater Extraction and Monitonng
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 2010.
W-32
Extraction
Off-Site
58-68
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 2010.
W-33
Extraction
Off-Site
60-70
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 2010.
W-34
Extraction
Off-Site
32-49
Groundwater Extraction and Monitonng
Weil Decommissioned
N/A
1996
Well decommissioned during October 2010. i
W-35
Extraction
Off-Site
40-50
Groundwater Extraction and Monitoring
Well Decommissioned
N/A
1996
Well decommissioned dunng October 2010
W-36
Extraction
Off-Site
42-52
Groundwater Extraction and Monitoring
Groundwater Extraction and Rebound Monitoring
Quarterly
1996-
Continue operaUon until EW-12 is abandoned,
W-37
Extraction
Off-Site
48-56
Groundwater Extraction and Monitonng
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound March 20TO.
W-38
Extraction
Off-Site
48-56
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1996-
Shut down to monitor for rebound MarGh 2010
W-40
Extraction
Off-Site
50-65
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Shut down August 2008 to monitor for rebound.
W-41
Extraction
Off-Site
50-70
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Shut down to monitor for rebound March 2010.
W-42
Extraction
Off-Site
50-60
Groundwater Extraction and Monitoring
Well Decommissioned
N/A
1997-2009
Well decommissioned during October 2010. !
W-43
Extraction
Off-Site
38-53
Groundwater Extraction and Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Shut down to monitor for rebound March 2010.
Performance
PW-01
Performance Monitoring
Off-Site
47-57
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
Resume quarterly monitoring January 2010
Monitoring (PW)
PW-02
Performance Monitoring
Off-Site
28-38
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
Resume quarterly monitoring January 2010 1
(for EOP Wells)
Ptf^3/4
Performance Monitoring
Off-Site
25-35
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
Resume quarterly monitonng January 2010 I
PW-05
Performance Monitoring
Off-Site
46-50
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
On-going edge of plume groundwater monitonng
PW-06
Performance Monitoring
Off-Site
41-51
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
On-going edge of plume groundwater monitoring 1
PW-07
Performance Monitoring
Off-Site
44-54
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
On-going edge of plume groundwater monitoring. i
PW-08
Performance Monitoring
Off-Site
43-48
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
On-going edge of plume groundwater monitoring. 1
PW-09
Performance Monitoring
Off-Site
30-35
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1993-
On-going edge of plume groundwater monitoring
PW-10
Performance Monitoring
Off-Site
62-72
Groundwater Monitoring
Groundwater Monitoring - Elevation Only
Quarterly
1994-1995
Well located west of Leach Creek not impacted by the groundwater plume.
PW-11
Performance Monitoring
Off-Site
36-41
Groundwater Monitoring
Groundwater Rebound Monitoring
Quarterly
1997-
Resumed quarterly monitoring January 2010
Groundwater samples collected for analysis from these monitoring welts.
No well was designated with the name W-39.
Table I
Page 2 of2
Figure 8 cont. Tacoma Landfill monitoring well status table.
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South Tacoma Channel Superfund Site Five-Year Review
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Table 4 Groundwater Monitoring Analytical Schedule
Chemical
Chemicai of
Concern
Indicator
Parameter
EPA Analytical
Method
Quantitation
Limit
Source/Comments
Quarterly
5emi-annual
Annual
Volatile Organic Compound
1,1, l-T richloroethane
X
3 26 OA
0.5 wg/L
VOC listed in ROD
X
1,1-Dlchloroethane
X
826OA
0.5 Mg/L
VOC listed in ROD
X
1,2-Dlchloroethane
X
826OA
0.5 Mg/L
VOC listed in ROD
X
1,2-Dlehloroethene, Total
X
826OA
0.5 ng/L
VOC not listed in ROD added during RDPS
X
Benzene
X
326OA
0.5 (Jg/L
VOC listed in ROD
X
Chloroethane
X
826OA
0-5 |_tg/L
VOC listed in ROD
X
Tetrachloroethene
X
826OA
0.5 Mg/L
VOC. not listed in ROD added during RDP5
X
Trichloroethene
X
826OA
0.5 Mg/L
VOC not listed in ROD added during RDPS
X
Vinyl Chloride
X
826OA
0.5 Mg/L
VOC listed in ROD
X
Metals
Arsenic (total)
X
6020A
5 Mg/L
Removed from COC list.
X
Manganese (total)
X
6020A
5 Mg/L
Discharge to Leach Creek Holding Basin; must
fie
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260 South Tacoma Channel Superfund Site Five-Year Review
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Appendix 3-A: Tacoma Landfill Documents
Reviewed
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262 South Tacoma Channel Superfund Site Five-Year Review
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Tacoma Landfill Documents Reviewed
AmTest Air Quality, 2011. Parametrix, Inc. @ City of Tacoma Landfill, Tacoma, Washington, Gas
Combustor Testing, December 16, 2010.
City of Tacoma, 2008a. Tacoma Landfill, Biannual Gas System Evaluation Report. January 1 - June
30, 2008.
City of Tacoma, 2008b. Annual Summary of Inspections for the Tacoma Landfill Cap, Condensate
Collection System, and Central Area Leachate Collection System. May 2008.
City of Tacoma, 2008c. Technical Memorandum, Subject: Tacoma Landfill Third 5-Year Review -
Modeled Effects on the Groundwater Divide Location Due to Potential Tacoma Water Wells
Production Increase. September 30, 2008.
City Of Tacoma, 2008d. Technical Memorandum, Subject: Tacoma Landfill - South End Perched
Leachate. October 20, 2008.
City of Tacoma, 2008e. Tacoma Landfill, Biannual Gas System Evaluation Report. July 1 - December
31.2008.
City of Tacoma, 2009a. Tacoma Landfill, Biannual Gas System Evaluation Report. January 1 - June
30, 2009.
City of Tacoma, 2009b. Tacoma Landfill Operations and Closure Plan. Revised February 2009.
City of Tacoma, 2009c. Tacoma Landfill Third Five-Year Closure Extension Request. February 27,
2009.
City of Tacoma, 2009d. Tacoma Landfill Consent Decree 2008 Annual Report. March 2009.
City of Tacoma, 2009e. Annual Summary of Inspections for the Tacoma Landfill Cap, Condensate
Collection System, and Central Area Leachate Collection System. March 2009.
City of Tacoma, 2009f. Letter to EPA, re: Tacoma Landfill - Gas Extraction Well and Probe Proposal.
March 17, 2009.
City of Tacoma, 2009g. Letter to EPA, re: Tacoma Landfill - Off-Site Gas Probe Data. May 8, 2009.
City of Tacaom, 2009h. Tacoma Landfill, Third Five-Year Closure Extension Request, Amendment
#1. June 8, 2009.
City of Tacoma, 2009i. Tacoma Landfill, Biannual Gas System Evaluation Report. July 1 - December
31.2009.
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City of Tacoma, 2009j. Tacoma Landfill, Extraction Wells Shutdown Request. December 3, 2009.
City of Tacoma, 2009k. Tacoma Landfill, Landfill Gas Management Plan. December 29, 2009.
City of Tacoma, 2010a. Tacoma Landfill, Biannual Gas System Evaluation Report. January 1 - June
30, 2010.
City of Tacoma, 2010b. Letter to EPA, re: Request for Modifications to the Closure Extension III
Conditional Approval. March 30, 2010.
City of Tacoma, 2010c. Annual Summary of Inspections for the Tacoma Landfill Cap, Condensate
Collection System, and Central Area Leachate Collection System. May 2010.
City of Tacoma, 2010d. Tacoma Landfill Consent Decree 2009 Annual Report. June 2010.
City of Tacoma, 2010e. Tacoma Landfill, Biannual Gas System Evaluation Report. July 1 - December
31,2010.
City of Tacoma, 201 Of. Tacoma Landfill, Addendum, Extraction Wells Shutdown Request. October
2010.
City of Tacoma, 2010g. Letter to EPA re: Tacoma Landfill - Stage 3 Closure - Central Area.
November 3, 2010.
City of Tacoma, 2010h. Tacoma Landfill, Groundwater Monitoring Plan. November 2010.
City of Tacoma, 20 lOi. Tacoma Landfill Institutional Controls Plan. November 2010.
City of Tacoma, 201 lj. Tacoma Landfill, Biannual Gas System Evaluation Report. January 1 - June
30, 2011.
City of Tacoma, 2011k. Annual Summary of Inspections for the Tacoma Landfill Cap, Condensate
Collection System, and Central Area Leachate Collection System. March 2011.
City of Tacoma, 20111. Tacoma Landfill Consent Decree 2010 Annual Report. March 2011.
City of Tacoma, 201 lm. Tacoma Landfill, Biannual Gas System Evaluation Report. July 1 -
December 31, 2011.
City of Tacoma, 2012a. Tacoma Landfill, Biannual Gas System Evaluation Report. January 1 - June
30, 2012.
City of Tacoma, 2012b. Tacoma Landfill Consent Decree 2011 Annual Report. March 2012.
City of Tacoma, 2012c. Tacoma Landfill, Biannual Gas System Evaluation Report. July 1 - December
31,2012.
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South Tacoma Channel Superfund Site Five-Year Review
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City of Tacoma, 2012d. Tacoma Landfill Institutional Controls Plan, Errata sheets. July 2012.
City of Tacoma, 2012e. Tacoma Landfill, Request to Decommission Extraction Wells W-30, W-40,
and W-41. November 2012.
City of Tacoma, 2013a. Tacoma Landfill Consent Decree 2012 Annual Report. March 2013.
City of Tacoma, 2013b. Annual Summary of Inspections for the Tacoma Landfill Cap, Condensate
Collection System, and Central Area Leachate Collection System. March 2013.
EPA, 2009a. Letter to City of Tacoma, re: Proposal for Gas Extraction Wells and Probes at Tacoma
Landfill Operable Unit of the South Tacoma Channel Superfund Site, Tacoma, Washington. August
20, 2009.
EPA, 2009b. Letter to City of Tacoma, re: Third Five-Year Closure Extension Request. December 21,
2009.
EPA, 2010a. Letter to City of Tacoma, re: Conditional Approval of Shutdown Request & Rebound
Monitoring Proposal for Extraction Wells at the Tacoma Landfill Operable Unit, South Tacoma
Channel Superfund Site. February 11, 2010.
EPA, 2010b. Letter to City of Tacoma, re: Modifications to the Closure Extension III Conditional
Approval. July 28, 2010.
EPA, 2010c. Letterto City of Tacoma, re: Amendment to Institutional Control Plan. November 1,
2010.
EPA, 2011. Letterto City of Tacoma, re: November 2010 Draft Landuse and Institutional Control
Plan. April 29, 2011.
Floyd|Snider, 2009a. Memorandum, re: Vinyl Chloride Issues from the Third 5-Year Review.
February 24, 2009.
Floyd| Snider, 2009b. Memorandum, re: Vapor Intrusion Evaluation for the Tacoma Landfill Off-site
Plume Area. August 28, 2009.
Floyd|Snider, 2009c. Memorandum, re: Arsenic and Human Health Exposure Issues from the Third 5-
Year Review. October 12, 2009.
Landau Associates, 2006. End of Plume Residual Plume Characterization Report, Tacoma Landifll -
North Area & South Area, Tacoma, Washington. February 1, 2006.
Landau Associates, 2010. Tacoma Landfill Groundwater Rebound Monitoring Plan, Tacoma,
Washington. September 15, 2010.
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State of Washington Department of Ecology (Ecology), 2010. Letter to City of Tacoma, re: Tacoma
Landfill Nested Gas Extraction Well Decommissioning and Construction Requirements. December 20,
2010.
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Appendix 3-B: Tacoma Landfill Site Inspection
Checklist
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Five-Year Review Site Inspection Checklist
I. SITE INFORMATION
Site name: Tacoma Landfill
Date of inspection: 4/2/2013
Location: Tacoma, WA
EPA ID: WAD980726301
Agency, office, or company leading the five-year
review: EPA
Weather/temperature: Cloudy, ~50 F
Remedy Includes: (Check all that apply)
£3 Landfill cover/containment
£3 Access controls
^Institutional controls
£3 Groundwater pump and treatment
ISI Surface water collection and treatment
Other: Groundwater monitoring
~ Monitored natural attenuation
~ Groundwater containment
~ Vertical barrier walls
Attachments: ~ Inspection team roster attached
~ Site map attached
II. INTERVIEWS (Check all that apply)
1. O&M site manager
Name
Interviewed ~ at site ~ at office ~ by phone Phone no.
Problems, suggestions; ~ Report attached
Title
Date
2. O&M staff
Name
Interviewed ~ at site Dat office ~ by phone Phone no.
Problems, suggestions; ~ Report attached
Title
Date
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3. Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency response
office, police department, office of public health or environmental health, zoning office, recorder of
deeds, or other city and county offices, etc.) Fill in all that apply.
Agency:
Contact:
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
Agency
Contact
Name Title Date Phone no.
Problems; suggestions; ~ Report attached
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4.
Other interviews (optional) ~ Report attached.
III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)
O&M Documents
~ O&M manual
~ As-built drawings
~ Maintenance logs
Remarks
~ Readily available
~Readily available
~ Readily available
~ Up to date ~ N/A
~ Up to date ~ N/A
~ Up to date ~ N/A
Site-Specific Health and Safety Plan ~ Readily available ~ Up to date ~ N/A
~ Contingency plan/emergency response plan ~ Readily available ~ Up to date ~ N/A
Remarks
O&M and OSHA Training Records ~ Readily available ~ Up to date ON/A
Remarks
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4. Permits and Service Agreements
~ Air discharge permit ~ Readily available ~ Up to date ~ N/A
~ Effluent discharge ~ Readily available QUp to date ~ N/A
~ Waste disposal, POTW ~ Readily available ~ Up to date ~ N/A
~ Other permits ~ Readily available ~ Up to date ~ N/A
Remarks
5. Gas Generation Records ~ Readily available ~ Up to date ~ N/A
Remarks
6. Settlement Monument Records ~ Readily available ~ Up to date ~ N/A
Remarks
7. Groundwater Monitoring Records
Remarks
~ Readily available ~ Up to date DN/A
Leachate Extraction Records
Remarks
~ Readily available ~ Up to date ~ N/A
9. Discharge Compliance Records
~ Air
~ Water (effluent)
Remarks
~ Readily available ~ Up to date ~ N/A
~ Readily available ~ Up to date ~ N/A
10. Daily Access/Security Logs
Remarks
~Readily available ~ Up to date ~ N/A
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IV. O&M COSTS
1. O&M Organization
~ State in-house
~ PRP in-house
~Federal Facility in-house
~ Other
2. O&M Cost Records
~ Readily available ~ Up to date
~ Funding mechanism/agreement in place
Original O&M cost estimate ~ Breakdown attached
Total annual cost by year for review period if available
From To ^Breakdown attached
Date
Date
Total cost
From
To
~ Breakdown attached
Date
Date
Total cost
From
To
~ Breakdown attached
Date
Date
Total cost
From
To
~ Breakdown attached
Date
Date
Total cost
From
To
~ Breakdown attached
Date
Date
Total cost
~ Contractor for State
~ Contractor for PRP
~ Contractor for Federal Facility
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3. Unanticipated or Unusually High O&M Costs During Review Period
Describe costs and reasons:
V. ACCESS AND INSTITUTIONAL CONTROLS M Applicable ~ N/A
A. Fencing
1. Fencing damaged ~ Location shown on site map ~ Gates secured ~ N/A
RemarksFencing on west side, near former pipe facility, damaged.
B. Other Access Restrictions
1. Signs and other security measures ~ Location shown on site map ~ N/A
Remarks Active transfer station, numerous signs on site.
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C. Institutional Controls (ICs)
1. Implementation and enforcement
Site conditions imply ICs not properly implemented ~ Yes ^ No ~ N/A
Site conditions imply ICs not being fully enforced ~ Yes £3 No ~ N/A
Type of monitoring (e.g., self-reporting, drive by)
Frequency
Responsible party/agency
Contact
Name Title Date Phone no.
Reporting is up-to-date ~ Yes ~ No ~ N/A
Reports are verified by the lead agency ~ Yes ~ No ~ N/A
Specific requirements in deed or decision documents have been met ~ Yes ~ No ~ N/A
Violations have been reported ~ Yes ~ No ~ N/A
Other problems or suggestions: ~ Report attached
2. Adequacy ~ ICs are adequate ~ ICs are inadequate ~ N/A
Remarks
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D. General
1. Vandalism/trespassing ~ Location shown on site map ~ No vandalism evident
Remarks Cal Taylor stated brass valves on gas wells stolen. The City replaced with plastic to avoid
future problems.
2. Land use changes on site ~ N/A
Remarks Central Area closed. Site continues to be used as a transfer station.
3. Land use changes off site ~ N/A
Remarks none
VI. GENERAL SITE CONDITIONS
A. Roads £3 Applicable ~ N/A
1. Roads damaged ~ Location shown on site map £3 Roads adequate ~ N/A
Remarks
B. Other Site Conditions
Remarks
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South Tacoma Channel Superfund Site Five-Year Review
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VII. LANDFILL COVERS M Applicable ~ N/A
A. Landfill Surface
1. Settlement (Low spots)
Areal extent
~ Location shown on site map ~ Settlement not evident
Depth
Remarks Documented in Annual reports
2.
Cracks
Lengths_
Remarks
~ Location shown on site map £3 Cracking not evident
Widths Depths
Erosion
Areal extent_
Remarks
~ Location shown on site map ^ Erosion not evident
Depth
Holes
Areal extent_
Remarks
~ Location shown on site map ^ Holes not evident
Depth
Vegetative Cover ^ Grass KlCover properly established
~ Trees/Shrubs (indicate size and locations on a diagram)
Remarks Vegetation on central area cap will be completed this year
~ No signs of stress
Alternative Cover (armored rock, concrete, etc.) ^ N/A
Remarks
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7. Bulges
Areal extent_
Remarks
~ Location shown on site map ^ Bulges not evident
Height
Wet Arcas/Water Damage ^ Wet areas/water damage not evident
~ Wet areas ~ Location shown on site map Areal extent_
~ Ponding ~ Location shown on site map Areal extent_
~ Seeps ~ Location shown on site map Areal extent_
~ Soft subgrade ~Location shown on site map Areal extent_
Remarks Wet areas during winter documented in annual report. None observed during site visit.
9. Slope Instability ~ Slides
Areal extent
Remarks
~ Location shown on site map ~ No evidence of slope instability
B. Benches
~ Applicable N/A
(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope
in order to slow down the velocity of surface runoff and intercept and convey the runoff to a lined
channel.)
1. Flows Bypass Bench
Remarks
~ Location shown on site map
~ N/A or okay
2. Bench Breached
Remarks
~ Location shown on site map
~ N/A or okay
3. Bench Overtopped
Remarks
~ Location shown on site map
~ N/A or okay
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C. Letdown Channels ~ Applicable ^ N/A
(Channel lined with erosion control mats, riprap, grout bags, or gabions that descend down the steep side
slope of the cover and will allow the runoff water collected by the benches to move off of the landfill
cover without creating erosion gullies.)
1. Settlement
Areal extent_
Remarks
~ Location shown on site map ~ No evidence of settlement
Depth
2. Material Degradation ~ Location shown on site map QNo evidence of degradation
Material type Areal extent
Remarks
Erosion
Areal extent_
Remarks
~ Location shown on site map ~ No evidence of erosion
Depth
Undercutting
Areal extent
Remarks
~ Location shown on site map ~ No evidence of undercutting
Depth
Obstructions Type
~ Location shown on site map
Size
Remarks
_ ~ No obstructions
Areal extent
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6. Excessive Vegetative Growth Type
~ No evidence of excessive growth
~ Vegetation in channels does not obstruct flow
~ Location shown on site map Areal extent
Remarks
D. Cover Penetrations £3 Applicable ~ N/A
1. Gas Vents Active ~ Passive
~ Properly secured/locked £3 Functioning £3 Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance
~ N/A
Remarks
2. Gas Monitoring Probes
~ Properly secured/locked ^ Functioning £3 Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks
3. Monitoring Wells (within surface area of landfill)
~ Properly secured/locked £3 Functioning £3 Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks
4. Leachate Extraction Wells
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~ Evidence of leakage at penetration ~ Needs Maintenance ~ N/A
Remarks Gas probes that collect leachate are pumped out
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South Tacoma Channel Superfund Site Five-Year Review
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5. Settlement Monuments ~ Located ^ Routinely surveyed DN/A
Remarks
E. Gas Collection and Treatment ~ Applicable DN/A
1. Gas Treatment Facilities
£3 Flaring ~ Thermal destruction ~ Collection for reuse
~ Good condition ~ Needs Maintenance
Remarks New, smaller flare installed
2. Gas Collection Wells, Manifolds and Piping
£3 Good condition ~ Needs Maintenance
Remarks
3. Gas Monitoring Facilities {e.g., gas monitoring of adjacent homes or buildings)
£3 Good condition ~ Needs Maintenance ~ N/A
Remarks
F. Cover Drainage Layer ^ Applicable ~ N/A
1. Outlet Pipes Inspected ~ Functioning ~ N/A
Remarks not inspected
2. Outlet Rock Inspected ~ Functioning ~ N/A
Remarks not inspected
G. Detention/Sedimentation Ponds Applicable ~ N/A
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1. Siltation Areal extent Depth ~ N/A
£3 Siltation not evident
Remarks
2. Erosion Areal extent Depth
ISI Erosion not evident
Remarks
3. Outlet Works ~ Functioning ^ N/A
Remarks
4. Dam ~ Functioning £3 N/A
Remarks
H. Retaining Walls ~ Applicable ^ N/A
I. Deformations ~ Location shown on site map ~ Deformation not evident
Horizontal displacement Vertical displacement
Rotational displacement
Remarks
2. Degradation ~ Location shown on site map ~ Degradation not evident
Remarks
I. Perimeter Ditches/Off-Site Discharge ~ Applicable N/A
1. Siltation ~ Location shown on site mapD Siltation not evident
Areal extent Depth
Remarks
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Vegetative Growth ~ Location shown on site map
~ Vegetation does not impede flow
Areal extent Type
Remarks
~ N/A
Erosion
Areal extent_
Remarks
~ Location shown on site map ~ Erosion not evident
Depth
Discharge Structure ~ Functioning ~ N/A
Remarks
VIII. VERTICAL BARRIER WALLS ~ Applicable |g| N/A
Settlement
Areal extent_
Remarks
~ Location shown on site map ~ Settlement not evident
Depth
2. Performance MonitoringType of monitoring_
~ Performance not monitored
Frequency
Evidence of breaching
Head differential
Remarks
IX. GROUNDWATER/SURFACE WATER REMEDIES M Applicable ~ N/A
A. Groundwater Extraction Wells, Pumps, and Pipelines
£3 Applicable ~ N/A
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1. Pumps, Wellhead Plumbing, and Electrical
~ Good condition El All required wells properly operating ~ Needs Maintenance ~ N/A
Remarks
2. Extraction System Pipelines, Valves, Valve Boxes, and Other Appurtenances
£3 Good condition ~ Needs Maintenance
Remarks
3. Spare Parts and Equipment
~ Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks not inspected
B. Surface Water Collection Structures, Pumps, and Pipelines £3 Applicable ~ N/A
1. Collection Structures, Pumps, and Electrical
£3 Good condition ~ Needs Maintenance
Remarks
2. Surface Water Collection System Pipelines, Valves, Valve Boxes, and Other Appurtenances
£3 Good condition ~ Needs Maintenance
Remarks
3. Spare Parts and Equipment
~ Readily available ~ Good condition ~ Requires upgrade ~ Needs to be provided
Remarks not inspected
C. Treatment System ~ Applicable N/A
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South Tacoma Channel Superfund Site Five-Year Review
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1.
Treatment Train (Check components that apply)
~ Metals removal ~ Oil/water separation ~ Bioremediation
~ Air stripping ~ Carbon adsorbers
~ Filters
~ Additive (e.£., chelation agent, flocculent)
~ Others
~ Good condition ~ Needs Maintenance
~ Sampling ports properly marked and functional
~ Sampling/maintenance log displayed and up to date
~ Equipment properly identified
~ Quantity of groundwater treated annually
~ Quantity of surface water treated annually
Remarks
2.
Electrical Enclosures and Panels (properly rated and functional)
~N/A ~ Good condition ~ Needs Maintenance
Remarks
3.
Tanks, Vaults, Storage Vessels
~N/A ~ Good condition ~ Proper secondary containment ~ Needs Maintenance
Remarks
4.
Discharge Structure and Appurtenances
~ N/A ~ Good condition ~ Needs Maintenance
Remarks
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5.
Treatment Building(s)
~ N/A ~ Good condition (esp. roof and doorways) ~ Needs repair
~ Chemicals and equipment properly stored
Remarks
6.
Monitoring Wells (pump and treatment remedy)
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~Good condition
~ All required wells located ~ Needs Maintenance ~ N/A
Remarks
D. Monitoring Data
5.
Monitoring Data
~ Is routinely submitted on time ~ Is of acceptable quality
6.
Monitoring data suggests:
£3 Groundwater plume is effectively contained ~ Contaminant concentrations are declining
D. Monitored Natural Attenuation
1.
Monitoring Wells (natural attenuation remedy)
~ Properly secured/locked ~ Functioning ~ Routinely sampled ~ Good condition
~All required wells located dNeeds Maintenance ON/A
Remarks
X. OTHER REMEDIES
If there are remedies applied at the site which are not covered above, attach an inspection sheet describing
the physical nature and condition of any facility associated with the remedy. An example would be soil
vapor extraction.
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XL OVERALL OBSERVATIONS
A.
Implementation of the Remedy
Describe issues and observations relating to whether the remedy is effective and functioning as designed.
Begin with a brief statement of what the remedy is to accomplish (i.e., to contain contaminant plume,
minimize infiltration and gas emission, etc.).
The purpose of the remedy is to prevent migration of the groundwater plume and protect
human health and the environment. The Central Area cap is complete; the only remaining item
is vegetation on one portion. Landfill gas continues to be extracted and burned at the flare.
Most of the GETS wells have been shutdown; only 5 remain in operation in areas of residual
plumes. The property will continue to be used as a transfer station and recycling center by the
City of Tacoma.
B.
Adequacy of O&M
Describe issues and observations related to the implementation and scope of O&M procedures. In
particular, discuss their relationship to the current and long-term protectiveness of the remedy.
The site appears to well maintained. Gas and groundwater are regularly monitored. The cap
has settlement and some ponding, typical of a landfill. The City pumps out ponded water on an
as needed basis.
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c.
Early Indicators of Potential Remedy Problems
Describe issues and observations such as unexpected changes in the cost or scope of O&M or a high
frequency of unscheduled repairs, that suggest that the protectiveness of the remedy may be
compromised in the future.
There are no indicators of remedy problems.
D.
Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
No optimization opportunities noted during the site visit.
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Appendix 3-C: Tacoma Landfill Site Inspection
Photographs
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290 South Tacoma Channel Superfund Site Five-Year Review
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Tacoma Landfill Site Inspection Photographs
Photo 2. Mothballed groundwater treatment system.
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Photo 3. Remaining portion of Central Area needing vegetation.
Photo 4. Completed cap with vegetation at Central Area
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South Tacoma Channel Superfund Site Five-Year Review
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Photo 6. Monitoring wells TL-11A, B and C
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Photo 7. Extraction well W-l
pp
. '¦ r .v T'F
^prr--* i' ¦ "•
1 ^ -V-'
eft
i
Photo 8. Elevated piping for gas extraction system at southern cap area.
294
South Tacoma Channel Superfund Site Five-Year Review
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Photo 10. Location of manholes for leachate monitoring and collection system.
OU 5/6, Tacoma Landfill 295
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Photo 11. Landfill flare.
Photo 12. Leach Creek gauging station.
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Appendix 3-D: Tacoma Landfill Interview
Transcripts
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298 South Tacoma Channel Superfund Site Five-Year Review
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Tacoma Landfill Interview Transcripts
Five Year Review Interview Record
Site Name: Tacoma Landfill, South Tacoma Channel Superfund Site
EPA ID No. WAD980726301
Interviewee: Dave Bosch, Tacoma Pierce County Health Department
Date: 22 April 2013
Interview Method: phone
Interview Contacts: Sharon Gelinas, USACE; Kristen Kerns, USACE
Interview Questions (responses are paraphrased)
1. What is your current role as it relates to the site? How long have you been aware of or
associated with the site?
Dave's title is Environmental Health Specialist II. He is in charge of overseeing regulation of
solid waste at the Tacoma landfill site.
2. What is your overall impression of the work conducted at the site to date?
Overall impression is that the remedy has been very effective. Capping and maintenance of the
cap has been effective at decreasing trends of COCs and allowed for the discontinuation of
monitoring extraction wells off site. Gas production at the site has decreased over time due to
the cap and the age of the landfill.
3. Have there been routine communications or activities (site visits, inspections, reporting
activities, etc.) conducted by your office regarding the site? (If so, please give purpose and
results.)
There is routine inspection of the solid waste handling and of the closed areas. Since 2009 the
health department has performed over 200 inspections. Also conduct inspections that focus on
construction activities, such as cap repairs.
4. Is there a continuous on-site O&M presence? If so, who are they? (contractors, etc).
Yes, the City maintains a constant on site presence.
Follow on Question: If there is no continuous on-site presence, describe staff and frequency of
site inspections and activities (e.g. what types of monitoring activities occur at what
frequencies).
City is responsible for continuous on site presence.
5. Would you say that O&M and/or sampling efforts have been optimized? Are there portions of
the remedy (e.g. the GETS) that show wear or may need additional focus during O&M?
The city has done a good job at assigning staff specifically to the remedial action activities to
ensure monitoring is performed and systems are maintained. Improvements could be made
regarding ponding on areas of the cap, specifically the sw corner and east of the central area
on the closed portion. This requires a balance between evaluating the impact to the areas
where ponding is occurring and the cost of the repairs. However, most of the ponding is not
considered a critical issue at this time. Ponding indicates that the water is not leaching through
the cap, however, it does indicate the cap is not functioning as intended. It is recommended
that the O&M plan for leachate developed in 1992 be updated to address more modern
activities associated with the landfill. Also need to update information regarding the asphalt
cap and its replacement with HDPE liner in high traffic areas.
OU 5/6, Tacoma Landfill
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6. What is the current status of construction? Have any problems or difficulties been encountered
that have impacted construction progress or implementability?
• Are there any other significant construction activities proposed?
There are no significant problems associated with the central area closure. The closure has
been split into three phases. Phase I in 2011 closed 15 acres in the southern portion of the
site. Phase II in 2012 closed an additional 7 acres and hydroseeded the phase I closure
area. Phase III will occur this summer and close the remaining 8 acres at the site. There
are cap repairs scheduled in the summer of 2013 for the parking lot west of the
administrative building. There will also be infrastructure installed for compressed natural
gas.
7. What does the monitoring data show?
• Are there any trends in the data that show contaminant levels are increasing or decreasing?
Trends show a decrease in contaminant levels overall. The Home Depot area is also
showing decrease concentrations overtime.
• Have any new or emerging COCs been identified?
No
8. Have there been unexpected O&M difficulties or costs at the site in the last five years? If so,
please give details.
No
9. Are you aware of any institutional controls, site access controls, new ordinances in place,
changes in actual or projected land use, complaints being filed or unusual activities at the site?
If so, please describe in detail.
There have been issues associated with flooding in the Fircrest neighborhood that the city is
addressing. This issue is not believed to be related to the landfill site. The city also
coordinated with a local highschool for a school project related to methyl mercury.
10. Are you aware of any ongoing community concerns regarding the site or its administration?
No
11. Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
A drunk driver crashed into the entrance gate, which subsequently required repairs. The fence
was cut through and bras valves from the gas extraction system were stolen. These were later
replaced. There are occasional emergency responses associated with public waste handling,
which is not related to the remedy.
12. Have any problems been encountered which required, or will require changes to this remedial
design or ROD?
No
13. Do you have any comments, suggestions, or recommendations regarding the site's
management, operation, or any other aspects of the site?
No
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Five Year Review Interview Record
Site Name: Tacoma Landfill, South Tacoma Channel Superfund Site
EPA ID No. WAD980726301
Interviewee: Chris Mauer, Department of Ecology
Date: 16 April 2013
Interview Method: phone
Interview Contacts: Sharon Gelinas, USACE; Kristen Kerns, USACE
Interview Questions (responses are paraphrased)
1. What is your current role as it relates to the site? How long have you been aware of or
associated with the site?
Chris is a project manager with Ecology for the Tacoma Landfill Site. He has been involved
with the project for 25 years.
2. What is your overall impression of the work conducted at the site to date?
The work at the site has been well done.
3. Have there been routine communications or activities (for example site visits, inspections,
reporting activities, etc.) conducted by your office regarding the site? If so, please give
purpose and results.
The project team used to meet monthly. Meetings were moved to quarterly and are now on an
as needed basis. Chris has no other recent communications or activities.
4. Would you say that O&M and/or sampling efforts have been optimized? Are there portions of
the remedy (for example the GETS) that show wear or may need additional focus during
O&M?
Efforts have been optimized. There are no portions of the remedy that need additional focus
during O&M.
5. Have there been unexpected O&M difficulties or costs at the site in the last five years? If so,
please give details.
There have been two occasions where rart of the site washed out. One incident was due to a
ruptured pipe that washed out the soil from beneath the cap. The other washout incident was
similar in nature. In both instances the City responded promptly to repair the damage.
6. What does the monitoring data show?
• Are there any trends in the data that show contaminant levels are increasing or decreasing?
The offsite plume has shrunk over the past decade and is almost completely contained
within the landfill boundary. This is part of the reason why off site monitoring wells have
been shut down.
• Have any new or emerging COCs been identified?
No. The site was initially well characterized.
7. Are you aware of any institutional controls, site access controls, new ordinances in place,
changes in actual or projected land use, complaints being filed or unusual activities at the site?
If so, please describe in detail.
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Not at this time. A land use control plan is in effect and was revised approximately three years
ago. Institutional controls, including fencing and prohibition against drilling wells for water,
are in effect.
8. Are you aware of any ongoing community concerns regarding the site or its administration?
Not in the past five years. Historically there were problems with odor but a control plan has
been put in place and has proven effective.
9. Are you aware of any events, incidents, or activities that have occurred at the site, such as
excavation, vandalism, trespassing, or emergency response from local authorities?
A well was destroyed by vandalism approximately ten years ago. Recently copper gas headers
were stolen.
10. Have any problems been encountered which required, or will require changes to this remedial
design or ROD?
No
11. Do you have any comments, suggestions, or recommendations regarding the site's
management, operation, or any other aspects of the site?
No
302
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Appendix 3-E: Tacoma Landfill Data Summary
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304 South Tacoma Channel Superfund Site Five-Year Review
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Tacoma Landfill Data Summary
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Table E-1
Wells '.villi Ef.ceetience of the Contingent Action Criteria
W*M No.
Date
Constityaitt
Result (ug/U
CAC Basis
CAC
PW-01
5/12/2010
I,l-Derte
1.S
Control Chart
1.7
W-02
11/9/2011
1,1- DicH'oroethane
2
Control Chart
1.8
W-02
9/16/2011
Benzene
1.9
RL
0.5
W-02
11/9/2011
Vinyl Chloride
1
Pred, Limit
0.8
W-03
3/11/2011
Trichloroetiiene
7.4
Control Chart
6,2
W-04
11/9/2011
1,1-Dichl oroethane
2.6
Control Chart
2.3
W-04
5/18/2011
Tetrachtoroethene
1
Pred. Limit
0.9
W-04
8/10/2011
Tetrachtoroethene
1
Pred, Limit
0.9
W-04
11/9/2011
Tetrachtoroethene
1.7
Pred. Limit
0.9
W-06
11/9/2011
1,l-Dichloroethane
3.3
Control Chart
2.7
W-06
11/9/2011
Tetrachtoroethene
0.91
RL
0.5
W-06
11/9/2011
Trfchloroethene
0.9 J
Pred, Limit
O.S
W-06
5/18/2010
Vinyl Chloride
0.6
Pred, Limit
0.5
W-06
3/10/2011
Vinyl Chloride
0.6
pred, Limit
0.5
W-06
11/9/2011
Vinyl Chloride
1
Pred. Limit
05
W-07
5/18/2011
1, l-Dichloroethane
2.8
Control Chart
2.7
W-0?
8/10/2011
1,1-Dichl oroethane
2,9
Control Chart
2.7
W-07
11/9/2011
1,1-Dichl oroethane
4.5
Control Chart
2.7
W-07
11/9/2011
Senzene
1,1
RL
0.5
W-07
S/10/2011
Chloroethane
0.61
RL
0.5
W-07
8/10/2011
Vinvl Chloride
1.
Pred, Limit
0.7
W-07
11/9/2011
Vinyl Chloride
1.3
Pred. Limit
0.7
W-OS
11/9/2011
1,l-Dichloroethane
1.8
Control Chart
0.9
W-08
11/9/2011
Genzerte
1.1
RL
0.5
W-08
5/18/2010
Tetrachtoroethene
1
RL
0.5
W-OS
11/9/2011
Tetrachtoroethene
0.91
RL
0.5
w-os
5/18/2010
TrEchloeaethene
2.6
RL
0.5
W-08
8/16/2010
Trichloroethene
1.7
RL
0.5
W-03
11/15/2010
Trichloroetlene
0.9
RL
0,5
W-OS
2/18/2011
Trichloroetbene
1,1
RL
0.5
W-OS
5/IS/2011
T rich lor oethene
0.7
RL
0.5
W-OS
11/9/2011
Trichtafoethene
1,1
RL
0,5
W-OS
5/18/2010
Vinvl Chloride
0.6
RL
0.5
W-OS
11/9/2011
Vinyl Chloride
0.8
RL
0.5
306
South Tacoma Channel Superfund Site Five-Year Review
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Table E-1
Wells with Exceedence of the Contingent Action Criteria
Well No,
Date
Constituent
Result (ug/lj
CAC Basts
CAC
W-09
5/18/2010
1,1-DicHoroetha.ne
0,9
RL
0.5
W-09
8/16/2010
1,1-Dicnloroetharie
0,8
RL
0.5
W-09
11/15/2010
1,1-Dichl or oe thane
0,3
RL
0.5
W-09
2/18/2011
l.l-Dicliioroetliane
1.3
RL
03
W-09
5/18/2011
U-DicWoraethsne
0.9
RL
0.5
W-09
8/10/2011
1,1-Dfchtoroethane
1
RL
0.5
W-09
11/9/2011
1, l-Da'cbloroefhane
2.4
RL
0.5
W-09
2/21/2012
1,1- Dichloroathane
0.9
RL
0.5
W-09
5/18/2010
Tetrachtoroethene
13
RL
0.5
W-09
8/16/2010
Tetrachloroethene
13
RL
0.5
W-09
11/15/2010
Tetrach'oroethene
1
RL
0.5
W-09
2/13/2011
Tetrschtoroethene
1.8
RL
0.5
W-09
5/18/2011
Tetrschloroethene
0.9
RL
0.5
W-09
S/10/2011
Tetrgchloroethane
1,1
RL
0.5
W-09
11/9/2011
Tetrachloroethene
1.6
RL
0.5
W-09
5/18/2010
Trichlorostfaene
3.2
Pred. Limit
0.6
W-09
8/16/2010
Trichloroethene
3.3
Pred. Limit
0.6
W-09
11/15/2010
TricWoroettiene
2.7
Pred, Limit
0.6
W-09
2/18/2011
Trichloroethene
2,3
Pred. Limit
0.6
W-09
5/18/2011
Trichloroetliene
2.6
Pred. Limit
0 6
W-09
8/10/2011
Trichloroethene
2,9
Pred, Limit
0.6
W-09
11/9/2011
TrrcMoroethene
2.5
Pred. Limit
0.6
W-09
2/21/2012
Trichloroethene
1,4
Pred, Limit
0.6
W-09
5/8/2012
Trichloroethene
1.3
Pred, Limit
0.6
W^9
8/20/2012
Trichloroe thane
1,2
Pred. Limit
0.6
W-09
11/6/2012
Trichloroe then?
1.1
Pred. Limit
0.6
W-09
5/18/2010
Vinyl Chloride
0.6
RL
03
W-09
2/18/2011
Vinyl Chloride
0.7
RL
03
W-09
11/9/2011
Vinyl Chloride
1.2
RL.
0.5
W-10
5/18/2010
1,1-Dichloroe thane
0.9
Pred, Limit
0.7
W-10
8/16/2010
1,1-D'cHoroettiane
0.S
Pred. Limit
0.7
W-10
11/15/2010
1,1-Dichloroethane
0.9
Pred. Limit
0.7
W-10
2/18/2011
1,1-Dichloroetha ne
1.2
Pred, Limit
0,7
W-10
5/18/2011
l,l-D?chloroethane
0.9
Pred. Limit
0.7
W-10
8/10/2011
1,1-Dichloroethane
1.1
Pred. Limit
0.7
W-10
11/9/2011
1,1-Dichloroe thane
2.4
Pred, Limit
0.7
W-10
2/21/2012
1,1-Dfchloroethane
0.9
Pred, Limit
0.7
W-10
5/S/2012
1,1-Dichloroethane
0,8
Pred, Limit
0.7
W-10
8/20/2012
1,1-Dichloroethane
0.9
Pred. Limit
0.7
W-10
5/18/2010
Tetrachl'oroethene
1.1
RL
03
W-10
3/16/2010
Tetrachtoroe then*
1.1
RL
03
W-10
11/15/2010
TetrachtoroMharie
1
RL
03
W-10
2/18/2011
Tetrachloroe there
1,5
RL
0.S
W-10
5/18/2011
Tetr achloroethene
0.9
RL
03
W-10
8/10/2011
Tetrachloroethene
1,2
RL
0,5
W-10
11/9/2011
Tetrachioroethene
1.6
RL
03
W-10
2/21/2012
Tetrachloroethene
0,6
RL
0.5
W-10
11/6/2012
Tetrachioroe thane
0,6
RL
03
W-10
5/13/2010
Trichloroe the ne
3
Pred. Limit
0.7
W-10
8/16/2010
Trfchtoroethene
3,1
Pred. Limit
0.7
W-10
11/15/2010
Trichloroe the ne
2,8
Pred. Limit
0.7
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Table E-1
Wells with Exc eerie nee of the Contingent Action Criteria
Well No
Date
Constituent
Result (ufc/1)
CAC Basis
CAC
W-10
2/18/2011
Trtchfcroe thane
2.1
Pred, Limit
0.7
W-10
5/1S/2011
Trichloroethene
23
Pred, Limit
0,7
W-10
a/10/20n
Trichloroethene
3.1
Pred Limit
0.7
W-10
11/9/2011
Trichloroethene
2.8
Pred. Limit
0.7
W-10
2/21/2012
Trichloroatheoe
1.6
Pred, Limit
0.7
W-10
5/8/2012
Trichloroethene
1,4
Pred, Limit
0.7
W-10
a/20/2012
Trichloroethene
1.8
Pred. Limit
0.7
W-10
11/8/2012
Trichloroethene
1.6
Pred. Limit
0.7
W-10
5/13/2010
Vinyl Chloride
0.4
Pred. Limit
0.3
W-10
2/18/2011
Vinyl Chloride
0,9
Pred. Limit
0.3
W-10
8/10/2011
Vinyl Chloride
0,6
Pred, Limit
0.3
W-10
11/9/2011
Vinyl Chloride
1.1
Pred. Limit
0.1
W-ll
5/19/2010
1,1-Dichloroethane
0,7
RL
0,5
__
3/16/2010
1,1-Dlchloroethane
0.7
RL
0.5
W-ll
11/16/2010
1,1-Dithloroe thane
0.7
RL
0.5
W-ll
2/22/2011
1.1-Dichloroethane
o.a
RL
0.5
W-ll
5/19/2011
1,1-Dichloroethane
0,7
RL
0,5
W-ll
8/10/2011
l,l-D>'cHloroe thane
0.9 J
RL
0.5
W-ll
11/9/2011
1,1-Dichloroethane
2
RL
0.5
W-ll
2/21/2012
1,1 - Dichl oroe thane
0.8
RL
0.5
w-ii 1
5/8/2012
1,1-Dichloroethane
0.9
RL
0.5
W-ll
3/20/2012
1,1-Dichloroe thane
0.8
RL
0,5
W-ll
11/6/2012
1,1-Dichloroethane
o.s
RL
0.5
W-ll
5/19/2010
Tetrachloroathene
o.s
RL
0.5
W-ll
8/16/2010
Tetrschforoethene
1
RL
0.5
W-ll
11/16/2010
Tetrachloroethene-
0,7
RL
0,5
W-ll
2/22/2011
Tetr^chioroethene
0.6
RL
0.5
W-ll
5/19/2011
Tetrachkiroethene
0.7
RL
0.5
W-ll
8/10/2011
Tatraehloroethena
1
RL
0.5
W-ll
11/9/2011
Tetrachloroethene
1,4
RL
0.5
w-n
5/8/2012
Tetrachloroethene
0.6
RL
0.5
w-ll
3/20/2012
Tetrachloroethene
0,6
RL
0.5
W-ll
5/19/2010
Trichloroethene
2,3
RL
0,5
W-ll
8/16/2010
Trichloroethene
2.5
RL
0.5
W-ll
11/16/2010
Trichloroetbene
1.7
RL
0.5
W-ll
2/22/2011
Trichloroethene
1.5
RL
0.5
W-ll
5/19/2011
Trichloroethene
1,9
RL
0.5
W-ll
£/10/2011
Trichloroethene
2.7
RL
0,5
W-ll
11/9/2011
Trichloroethene
2.6
RL
0.5
W-ll
2/21/2012
Trichloroethene
L4
RL
0.5
W-ll
5/8/2012
Trichloroethene
1.4
RL.
0.5
W-ll
6/20/2012
Trichloroathene
1.5
RL
0.5
W-ll
11/6/2012
Trichloroethene
1.5
RL
0.5
W-ll
8/10/2011
Vinyl Chloride
0.7
RL
0.5
W-ll
11/9/2011
Vinyl Chloride
0.9
RL
0.5
W-M
3/12/2010
1,1-Dichloroethane
0.7
Pred. Limit
0-6
W-M
8/12/2010
Tetrschforoethene
1.9
Pred, Limit
0.5
W-10
11/10/2011
Tetrachloroethsne
1
Pred. Limit
0.5
W-M
8/12/2010'
Trichloroethene
1,3
Pred. Limit
0,5
W-M
11/10/2011
Trichloroethene
O.S1
Pred, Limit
0.5
W-15
11/10/2011
1,1-Dichloroethane
2 2
Control Chart
1.5
308
South Tacoma Channel Superfund Site Five-Year Review
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Table E-1
Weils with Exceedence of She Contingent Action Criteria
Wall No.
Date
Constituent
Result fug/M
CAC Basis
CAC
W-1S
11/10/2011
Benzene
0,9.1
RL
0.5
W-15
11/10/2011
Tetrachloroethene
2.3
Control Chart
1.9
W-15
11/10/2011
Trichloroethene
1,9
Control Chart
1.7
W-16
11/10/2011
1,1-DicHoroe thane
1.9
Control Chart
1.8
W-16
5/19/2010
Tetrachlorosthene
0.9
RL
0.5
W-16
8/17/2010
Tetrachlorosthene
I
RL
0.5
W-16
11/10/2011
Tetrach ioroethene
1.1
RL
0.5
W-16
5/19/2010
Trichloroethene
2,1
RL
0,5
W-16
8/17/2010
Trichloroethene
2.2
RL
0.5
W-16
11/16/2010
Triehloroethene
0,9
RL
0.5
W-16
8/11/2011
Trichloroethene
0.7 i
RL
0.5
W-16
11/10/2011
Trichloroethene
1,3
RL
0.5
W-17
11/10/2011
Tetrachlorosthene
0,?. 1
RL
05
W-17
11/10/2011
Trichloroethene
0.8 1
RL
0,5
W-18
5/19/2010
1,1-Dichloroethane
0.7
RL
0.5
W-1S
a/17/2010
1,1-Dichloroethane
o.s
RL
0.5
W-1S
11/16/2010
1,1-Dichloroethane
0.9
RL
0.5
W-1S
2/22/2011
1,1-Dicnloroethane
1
RL
0.5
W-1S
5/19/2011
1,1-DicNoroethsne
0,9
RL
0.5
W-18
8/11/2011
1,1-Dlehloroethane
Q.9J
RL
0.5
W-18
11/10/2011
1,1-Dichloroethane
2.2
RL
0.5
W-1S
2/22/2012
1, l-DcNoroetba ne
0,9
RL
0.5
W-18
S/21/2012
I.l-Dlehloroethane
0.8
RL
0.5
W-18
8/17/2010
Tetraehloroe thane
0.S
RL
0.5
W-18
11/16/2010
Tetrach Ioroethene
O.S
RL
0.5
W-18
2/22/2011
Tefrachloroetben#
0,9
RL
0.5
W-18
5/19/2011
Tetrachioroethene
0.8
RL
0.5
W-18
8/11/2011
TetrachSaroetherie
0.9 J
RL
0.5
W-1S
11/10/2011
T a trach Ioroethene
1.5
RL
0.5
W-15
5/19/2010
Trichloroethene
1
RL
0.5
W-18
5/17/2010
Trichloroethene
2
RL
0.5
W-18
11/16/2010
Trichloroethene
2
RL
0.5
W-18
2/22/2011
Trichloroethene
1,5
RL
0.5
W-18
5/19/2011
Trichloroethene
2.1
RL
0.5
W-18
8/11/2011
Trichloroethene
1,9
RL
0.5
W-1S
11/10/2011
Trichloroethene
2.4
RL
0.5
W-18
2/22/2012
Trichloroethene
1.3
RL
0.5
W-18
5/14/2012
Trichloroethene
0,8
RL
0,5
W-18
8/21/2012
Trichloroethene
1.1
RL
0.5
W-18
2/22/2011
Vinyl Chloride
0.9
Pred. Limit.
0.6
W-18
11/10/2011
Vinyl Chloride
1.3
PreU. Limit
0.6
W-19
11/10/2011
1.1-Dicnloroethane
1.1
RL
0.5
W-20
2/22/2011
1,1-Dichloroethane
0,7
RL
0.5
W-20
5/19/2011
1,1-Dkhloroethane
0.7
RL
0.5
W-20
11/10/2011
1,1-Dichloroethane
1
RL
0.5
W-20
2/22/2011
Tetrach Ioroethene
0.8
RL
0.5
W-20
5/19/2011
Tetrach Ioroethene
0,8
RL
0.5
W-20
11/10/2011
Tetrach tor oe thane
0.9 J
RL
0.5
W-20
8/17/2010
Trichbrcethene
0.6
RL
0.5
W-20
11/16/2010
Trichloroethene
1
RL
0.5
W-20
2/22/2011
Trichloroethene
1,1
RL
0.5
OU 5/6, Tacoma Landfill
309
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Table E-1
Wells '.villi Ef.ceetience of the Contingent Action Criteria
Well No.
Oats
Constituent
Result (ug/L)
CAC Basis
CAC
W-20
5/13/2011
Trich lor oe then®
1.3
RL
0.5
W-ZO
11/10/2011
Trichloraethene
1
RL
0.5
W-21
5/15/2010
1,1-DfcWorcsetharse
O.S
RL
0.5
W-21
2/22/2011
1,1-Dichl oroethane
0.6
RL
0.5
W-21
8/11/2011
1,1-DicHoroetba.ns
0.9 i
RL
0.5
W-21
11/10/2011
1,1-Dichl oroethane
1.4
RL
0.5
W-21
5/19/2010
Tetrachloroethene
0.8
RL
0.5
W-21
8/11/2011
Tetraehloroethene
O.S i
RL
0.5
W-21
11/10/2011
Tetrochioroethene
0.9 1
RL
0.5
W-21
5/19/2010
Trichtoroethene
2,1
RL
0.5
W-21
8/17/2010
Trichloroethene
0.9
RL
0.5
W-21
2/22/2011
Trichlorcw thane
0.8
RL
0.5
W-21
5/19/2011
Trichloroethene
0,7
RL
0,5
W-21
S/ll/2011
Trfchloraettwne
1.7
.RL
0.5
W-21
11/10/2011
Trichkxoetftene
1.2
RL
0.5
W-22
5/19/2010
1,1-Dichloroe thane
O.S
RL.
0-5
W-22
8/17/2010
1,1-Dicrtoroe thane
0.8
RL
0.5
W-22
11/16/2010
1,1-Dichl oroe thane
0,9
RL
05
W-22
2/22/2011
ifl-DicH'Qroethane
U
RL
0.5
W-22
5/19/2011
1,1-Dichl oroethane
0.7
RL
0.5
W-22
9/11/2011
1,1-Dichloroe thane
1,1
RL
0.5
W-22
11/10/2012
1.1-Dichloroe thane
2.4
RL
0.5
W-22
2/22/2012
1,1-Diehloroe thane
0.3
RL
0.5
W-22
5/9/2012
1.1-Dichl oroethane
0.9
RL
0.5
W-22
8/21/2012
1,1-Dichloroe thane
0.7
RL
0.5
W-22
11/6/2012
1,1-Dichl oroetha ne
0.6
RL
0-5
W-22
8/17/2010
Tetraehioroethene
0.6
RL
05
W-22
11/16/2010
Tetrschloroethene
0.6
RL
0.5
W-22
2/22/2011
Tatrachioroethene
0.6
RL
0.5
W-22
5/19/2011
Tetrachioroethene
0.8
RL
0.5
W-22
11/10/2011
Tetrechloroethene
1.4
RL
0.5
W-22
2/22/201.1
Vmyl Chloride
O.S
Pred. Linn:!
0.4
W-31
11/5/2012
Trich lores thene
0.9
RL
0.5
W-36
11/17/2010
1,1-Dichl oroethane
1
RL
0.5
W-36
8/14/2012
Ll-Dichloraethsne
0.8
RL
0.5
W-36
11/5/2012
1,1-Dicol oroethane
0.6
RL
0.5
W-36
5/17/2010
Chlorcii? thane
2.2
RL
0.5
W-36
11/17/2010
Tetrachloroethene
0,6
RL
0,5
W-36
8/14/2012
Tatrachioroethene
0.7
RL
0.5
W-36
11/17/2010
Trichloroethene
17
RL
0.5
W-36
8/14/2012
Trichloroethene
1.8
RL
0-5
W-36
11/5/2012
Trichloroetiierie
1.5
RL
0-5
W-41
6/14/2012
Trichloroethene
1
RL
0,5
W-43
2/37/2011
Vinyl Chloride
0.5
Pred. Limit
0.3
Notes;
CAC- Contingent action criteria.
Control Chart -CAC calculated using Shewarl-CUSUM control chart
ftL - CAC set at historical reporting limit
Precl. Limit - CAC calculated using n on-parametric prediction limit
310
South Tacoma Channel Superfund Site Five-Year Review
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Table E-Z
Mann-KendaII Test for Trend Results
Well No.
Constituent
Mann-Kendall Results
Confidence Factor
Trend Result
PW-01
1,1-Dichloroethane
92.9%
Prob Increasing
TL-11B
1,1-Dlchloroetha ne
99.0%
Decreasing
W-02
1, l-Dfehlorae thane
84.0%
Stable
W-04
1,1-Df chloroetha ne
72.9%
No Trend
W-06
1,1-DFchloroe thane
59.0%
No Trend
W-07
1,1-Dichloroetha ne
56.0%
No Trend
W-OS
1,1-Dtchloroe tha ne
96.4%
Decreasing
W-G9
1,1-Drchloroethane
87.5%
Stable
W-10
1,1-Dichioroe thane
70,3%
Stable
W-ll
1.1-Dichloroethane
94,9%
Prob increasing
W-14
1,1-Dfchloroetha ne
98.0%
Decreasing
w-is
1,1-Dichloroetha ne
85.9%
Stable
W-16
1,l-Dfchloroe thane
92.9%
Prob Increasing
W-IS
1, 1-Dtchloroetha ne
70.3%
Stable
W-19
1,1-Dfchloroetha ne
90.5%
Prob Decreasing
W-21
1,1-Dichloroe thane
92.9%
Prob Decreasing
W-22
1,1-Dichloroe thane
67.6%
Stable
W-36
1, l-Dfchloroe tha ne
45.1%
Stable
TL-05C
1,2-Dichloroetha ne
67.6%
Stable
TL-07A
1,2-Dfchioroetha ne
67.6%
Stable
TL-llA
Benzene
85.9%
Stable-
W-02
Benzene
89.1%
No Trend
W-07
Benzene
94.0%
Prob Decreasing
W-08
Benzene
94.0%
Prob Decreasing
W-15
Benzene
91.8%
Prob Decreasing
W-07
Ch 1 of oe thane
95.7%
Decreasing
W-36
Ch lor oe thane
99.5%
Decreasing
PW-11
Tetrachloroethene
90.5%
Prob Decreasing
TL-11B
Tetrachloroethene
90.5%
Prob Decreasing
W-04
Tetrachloroethene
77.7%
No Trend
W-06
Tetrachl or oethe ne
90.5%
Prob Decreasing
W-08
Tetrachloroethene
97.0%
Decreasing
W-09
Tetrachl oroethe ne
99.2%
Decreasing
W-10
Tetrachloroethene
94.9%
Prob Decreasing
W-ll
Te trachl oroethe ne
92.9%
Prob Decreasing
W-14
Tetrachloroethene
95.7%
Decreasing
W-15
Tetrachloroethene
77.7%
Stable
W-16
Tetrachloroethene
98.4%
Decreasing
W-17
Tetr achlor oethe ne
90.5%
Prob Decreasing
W-IS
Tetrachloroethene
85.9%
Stable
W-20
Tetrachloroethene
84.0%
Stable
W-21
Tetrachloroethene
91.8%
Prob Decreasing
W-22
Tetrachl oroethe ne
S7.5%
Stable
W-36
Tetrachloroethene
77.7%
Stable
TL-11B
Trichloroethene
85.9%
Stable
W-03
Trichloroethene
64.8%
Stable
W-06
Trichloroethene
95.7%
Decreasing
W-OS
Trichloroethene
100.0%
Decreasing
W-09
Trichloroethene
>99.9%
Decreasing
W-10
Trichloroethene
98.7%
Decreasing
OU 5/6, Tacoma Landfill
311
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Table E-2
Marin-Kendall Test for Trend Results
Wal! Ho,
Constituent
Mann-Kendall Remits
Confidence Factor
Trend1 Result
W-ll
Trichloroethenc
89.1%
Stable
W-14
Trichiomethene
97.5%
Decreasing
W-15
Trichloroethene
91.8%
Pi ob Decreasing
W-lb
Tridiioraethane
99.7%
Decreasing
W-1S
Trichloroethene
90.5%
Prob Decreasing
W-20
TricHoroethene
94.9%
Prob Decreasing
W-21
Trichioroethene
99.4%
Decreasing
W-Bl
Tnehloroethene
77.7%
Stable
W 36
Tnehloroethene
53.0%
No Trend
W-41
Trichioroethene
63.6%
Stable
W-02
Vinyl Chloride
S3.2%
Stable
W-0&
Vinyl Chioride
39.1%
Stable
W-07
Vinyl ChSoride
87.5%
Stable
W-OS
Vinyl Chloride
94.9%
Prob Deaeasing
W-09
Vinyl Chloride
96.4%
Decreasing
W-10
Vinyl Chloride
92.9%
Prob Decreasing
W-ll
Vinyl ChfaricK
37.5%
Stable
W-1S
Vinyl ChSoride
70.5%
Stable
W-22
Vinyl ChSoride
67.6%
Stable
W-43
Vinyl Chloride
91.8%
Prob Decreasing
Notes:
Well showed increasing trends
312
South Tacoma Channel Superfund Site Five-Year Review
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3/1/2010 9/17/2010 4/5/2011 10/22/2011 5/9/2012 11/25/2012
Date
Figure E-l. 1,2-dichloroethane (DCA) concentrations at wells that exceeded the contingent action criteria.
313
OU 5/6, Tacoma Landfill
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0 H 1 1 1 1 1
3/1/2010 9/17/2010 4/5/2011 10/22/2011 5/9/2012 11/25/2012 6/13/2013
Date
Figure E-2. Benzene concentrations at wells that exceeded the contingent action criteria.
314
South Tacoma Channel Superfund Site Five-Year Review
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2.5
2
DO
3
C
o
1.5
£
01
(J
c
0
u
01
£
(G
01
O
u
0.5
0
3/1/2010
¦W-07
¦W-36
9/17/2010
4/5/2011
10/22/2011
Date
5/9/2012 11/25/2012 6/13/2013
Figure E-3. Chloroethane concentrations at wells that exceeded the contingent action criteria.
OU 5/6, Tacoma Landfill
315
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0 -I 1 1 1 1 1
3/1/2010 9/17/2010 4/5/2011 10/22/2011 5/9/2012 11/25/2012 6/13/2013
Date
Figure E-4. 1,2-dichloroethane concentrations at wells that exceeded the contingent action criteria.
316
South Tacoma Channel Superfund Site Five-Year Review
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2.5
0
3/1/2010
9/17/2010
1
4/5/2011
10/22/2011
Date
1
5/9/2012
11/25/2012
6/13/2013
Figure E-5. Tetrachloroethene (PCE) concentrations at wells that exceeded the contingent action criteria.
OU 5/6, Tacoma Landfill
317
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DO
3
C
o
c
a>
u
c
o
u
y 3
0
3/1/2010 9/17/2010 4/5/2011
TL-11B
W-03
W-06
W-08
W-09
W-10
W-ll
W-14
W-15
W-16
W-18
W-20
W-21
W-31
W-36
W-36
10/22/2011
Date
5/9/2012 11/25/2012 6/13/2013
Figure E-6. Trichloroethene (TCE) concentrations at wells that exceeded the contingent action criteria.
318
South Tacoma Channel Superfund Site Five-Year Review
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0 -I 1 1 1 1 1
3/1/2010 9/17/2010 4/5/2011 10/22/2011 5/9/2012 11/25/2012 6/13/2013
Date
Figure E-7. Vinyl Chloride concentrations at wells that exceeded the contingent action criteria.
OU 5/6, Tacoma Landfill
319
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320 South Tacoma Channel Superfund Site Five-Year Review
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