FIFTH FIVE-YEAR REVIEW REPORT FOR
TULALIP LANDFILL SUPERFUND SITE
SNOHOMISH COUNTY, WASHINGTON
£
<
n
\
ro
PRO^
0
May 2023
Prepared by
U.S. Environmental Protection Agency
Region 10
Seattle, Washington
Digitally signed by
CALVIN TERADA
Date: 2023.05.04
10:47:39-07'00'
Calvin J. Terada, Division Director Date
CALVIN
TERADA
-------
Table of Contents
LIST 01 ABBREVIATIONS & ACRONYMS 3
I. INTRODUCTION 4
Site Background 4
FIVE-YEAR REVIEW SUMMARY FORM 5
II. RESPONSE ACTION SUMMARY 7
Basis for Taking Action 7
Response Actions 8
Status of Implementation 9
Institutional Control (IC) Review 11
Systems Operations/Operation and Maintenance (O&M) 14
III. PROGRESS SINCE THE PREVIOUS REVIEW 17
IV. FIVE-YEAR REVIEW PROCESS 18
Community Notification, Community Involvement and Site Interviews 18
Data Review 19
Site Inspection 20
V. TECHNICAL ASSESSMENT 21
QUESTION A: Is the remedy functioning as intended by the decision documents? 21
QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid? 22
QUESTION C: Has any other information come to light that could call into question the protectiveness of the
remedy? 22
VI. ISSUES/RECOMMENDATIONS 23
OTHER FINDINGS 23
VII. PROTECTIVENESS STATEMENT 24
VIII. NEXT REVIEW 24
APPENDIX A - REFERENCE LIST A-l
APPENDIX B - SITE CHRONOLOGY B-l
APPENDIX C - HISTORICAL LEACHATE SEEP ANALYTICAL DATA C-l
APPENDIX D - INTERVIEW FORMS D-l
APPENDIX E - DATA REVIEW FIGURES AND TABLES E-l
APPENDIX F - SITE INSPECTION PHOTOS F-l
APPENDIX G - SITE INSPECTION CHECKLIST G-l
APPENDIX H - ARARS REVIEW 11-1
Tables
Table 1: Off-Source (OU1) COCs, by Media 7
Table 2: Summary of Planned and/or Implemented Institutional Controls (ICs) 12
Table 3: Protectiveness Determinations/Statements from the 2018 FYR Report 17
Table 4: Protectiveness Determinations/Statements from the 2020 FYR Addendum Report 17
Table 5: Status of Recommendations from the 2018 FYR Report 18
Table 6: Range of Detected Methane and Carbon Dioxide in Landfill Gas Vents, 2018 to 2022a 19
Table B-l: Site Chronology B-l
Table C-l: Leachate Seep Analytical Data, 1994 to 2009 C-l
Table C-2: Surface Water Quality Standards C-4
Table E-l: Settlement Survey Data - Fill Area Slopes E-5
Table E-2: Settlement Survey Data - Cut Area Slopes E-5
Table H-l: OU2 Surface Water Standards Comparison H-l
1
-------
Figures
Figure 1: Site Map 6
Figure 2: Site Parcel Mape 13
Figure 3: Landfill Monitoring Locations 16
Figure E-l: Landfill Gas Composition in GVS-1, GVS-2 and GVS-3 E-l
Figure E-2: Landfill Gas Composition in GVS-4, GVS-5 and GVS-6 E-2
Figure E-3: Historical Leachate Elevations E-3
Figure E-4: Site Infrastructure E-4
2
-------
LIST OF ABBREVIATIONS & ACRONYMS
ARAR
Applicable or Relevant and Appropriate Requirement
AWQC
Ambient Water Quality Criteria
BRA
Baseline Risk Assessment
CERCLA
Comprehensive Environmental Response, Compensation, and Liability Act
CFR
Code of Federal Regulations
COC
Contaminant of Concern
CSL
Cleanup Screening Level
Ecology
Washington State Department of Ecology
EPA
United States Environmental Protection Agency
FS
Feasibility Study
FYR
Five-Year Review
IC
Institutional Control
LFG
Landfill Gas
mg/L
Milligrams per Liter
MTCA
Model Toxics Control Act
NCP
National Contingency Plan
NPL
National Priorities List
O&M
Operation and Maintenance
OU
Operable Unit
PAH
Polycyclic Aromatic Hydrocarbon
PCB
Polychlorinated Biphenyl
ppm
Parts per Million
PRP
Potentially Responsible Party
RAO
Remedial Action Objective
RI
Remedial Investigation
ROD
Record of Decision
RPM
Remedial Project Manager
SMS
Sediment Management Standard
Tribes
The Tulalip Tribes of Washington
UU/UE
Unlimited Use and Unrestricted Exposure
USACE
U.S. Army Corps of Engineers
VOC
Volatile Organic Compound
WAC
Washington Administrative Code
3
-------
I. INTRODUCTION
The purpose of a five-year review (FYR) is to evaluate the implementation and performance of a remedy to
determine if the remedy is and will continue to be protective of human health and the environment. The methods,
findings and conclusions of reviews are documented in FYR reports such as this one. In addition, FYR reports
identify issues found during the review, if any, and document recommendations to address them.
The U.S. Environmental Protection Agency (EPA) is preparing this FYR pursuant to the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) Section 121, consistent with the National
Contingency Plan (NCP) (40 Code of Federal Regulations (CFR) Section 300.430(f)(4)(ii)), and takes into
consideration EPA policy.
This is the fifth FYR for the Tulalip Landfill Superfund site ("Site"). The triggering action for this statutory
review is the completion date of the previous FYR. The FYR has been prepared because hazardous substances,
pollutants or contaminants remain at the Site above levels that allow for unlimited use and unrestricted exposure
(UU/UE).
The Site consists of two operable units (OUs). OU1 is the wetlands portion of the Site, also known as the off-
source area. OU2 addresses the landfill portion of the Site, also known as the on-source area. This FYR Report
addresses both OUs.
EPA remedial project manager (RPM) Rebecca C. Feldman led the FYR. The Washington State Department of
Ecology (Ecology) participated in the review process. The Tulalip Tribes of Washington (the Tribes), the owners
of the landfill property, were notified of the initiation of the FYR. EPA contractor Skeo provided support for the
FYR. The review began on August 2, 2022.
Appendix A lists the documents reviewed for this FYR. Appendix B provides a chronology of significant site
events.
Site Background
The Site is a former landfill located on North Ebey Island in the Snohomish River delta, between the cities of
Marysville and Everett, Washington, and within the boundaries of the Tulalip Tribes of Washington Reservation
(Figure 1). The Site consists of a 147-acre on-source area (landfill) and a 160-acre off-source area (wetlands).
The Seattle Disposal Company operated the landfill, also known as the Big Flats landfill, from 1964 to 1979,
under a lease from the Tribes. The landfill received an estimated 3 million to 4 million tons of commercial and
industrial waste. During operations, Seattle Disposal Company and others brought refuse to the Site by barge and
truck. Two canals (north and south) were dredged on the island to allow access for the barges. The north canal
was reportedly dredged to a depth of 12 feet to 30 feet below mean sea level. The dredge material was used to
construct the perimeter berm around the landfill. Over time, the canals were filled in with refuse during landfill
operations.
In 1979, landfill operators closed the landfill under a consent decree between the United States, Seattle Disposal
and the Tribes. They added a soil cover and constructed a perimeter berm. Insufficient grading of the soil cover
resulted in poor drainage and allowed precipitation to collect and infiltrate the landfill surface. As a result,
leachate formed within the landfill and then discharged to and contaminated the surrounding wetlands and tidal
channels. EPA listed the Site on the Superfund program's National Priorities List (NPL) in 1995. After
construction of a new engineered landfill cap, EPA deleted the Site from the NPL in 2002.
The closed and capped landfill is bounded by Ebey Slough to the north, Steamboat Slough to the south, Puget
Sound to the west, and wetlands and Interstate 5 to the east (Figure 1). A locked gate at the eastern entrance to the
landfill restricts access to the Site. Existing Site features include cover-system components, access roads and
fences. A maintenance shed, office trailer and animal shelters for two goats and a llama are located on a gravel
pad near the center of the landfill. Surrounding wetlands are relatively undisturbed by human activity. They are
4
-------
occasionally used for duck hunting.
There are three water-bearing zones at the Site - Zone 1, Zone 2 and the Deeper Zone. Zone 1, or leachate, is
groundwater within the refuse layer. Zone 2 is a silty sand zone below the refuse. The Deeper Zone consists of
sand, silty sand and clay. It extends to about 100 feet under the landfill. Groundwater under the Site is brackish
and unusable as a potable water source. Site studies indicate that groundwater from the landfill migrates and
discharges to the wetlands and sloughs. Elevated site risks are associated with human ingestion of shellfish living
in sediment in some tidal channels around the landfill. Ecological risks are associated with sediment in some tidal
channels around the landfill and with wetland soil adjacent to most of the leachate seeps on the landfill berm. The
wetlands surrounding the landfill play an important ecological role in the Snohomish River Delta and Puget
Sound.
FIVE-YEAR REVIEW SUMMARY FORM
SITE IDENTIFICATION
Site Name: Tulalip Landfill
EPA ID: WAD980639256
Region: 10
State: Washington City/County: Marysville/Snohomish
NPL Status: Deleted
Multiple OUs?
Yes
Lead agency: EPA
Has the Site achieved construction completion?
Yes
REVIEW STATUS
Author name: Rebecca C. Feldman, with additional support provided by Skeo
Author affiliation: EPA Region 10
Review period: 8/2/2022 - 4/14/2023
Date of site inspection: 10/20/2022
Type of review: Statutory
Review number: 5
Triggering action date: 4/23/2018
Due date (fiveyears after triggering action date): 4/23/2023
5
-------
• Marysville, WA
Disclaimer: This map and any boundary lines within the map are approximate and
subject to change. The map is not a survey. The map is for informational purposes
only regarding EPA's response actions at the Site. Map image is the intellectual
property of Esri and is used herein under license. Copyright © 2020 Esri and its
licensors. All rights reserved. Sources: Esri, Maxar, the 1998 ROD and the 2021
Annual Site Inspection Memorandum.
Tulalip Landfill Superfund Site
City of Marysville, Snohomish County, Washington
Last Modified: 12/16/2022
Figure 1: Site Mai
Tulalip Landfill
Office
Approximate Site Boundary
I \l OU1 (Wetlands)
EH3 OU2 (Landfill)
6
-------
II. RESPONSE ACTION SUMMARY
Basis for Taking Action
The Site's 1995 remedial investigation (RI), completed by PRPs under an August 1993 Administrative Order on
Consent, found that leachate leaving the landfill exceeded water quality criteria and standards.1 The leachate
flowed directly into sensitive, ecologically valuable wetlands that surround the landfill, and into sloughs
connected with the Snohomish River and Puget Sound.
EPA conducted a streamlined risk assessment in 1995 that considered risks to current and future recreational,
industrial and commercial users, and to ecological receptors from the landfill source area (OU2). It found that
detected concentrations of chemicals in leachate, surface water, groundwater, soil and sediment exceeded human
health screening criteria and ecological screening criteria.2
Chemicals found in leachate seeps at levels at least an order of magnitude greater than the human health screening
values included several pesticides, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs)
and arsenic. Chemicals exceeding the comparison numbers in soils and sediments adjacent to the landfill surface
included two PCBs, arsenic, beryllium, heptachlor epoxide and PAHs (see Table H-l for additional chemicals in
OU2). Of these chemicals, arsenic had the highest frequency of exceedance. The exceedances indicated the
potential for adverse effects on people that use the Site, and to animals and plants that live on or near the landfill
and contact these media. The results served as the basis for the interim remedial action at the OU2 landfill source
area.
EPA's 1997 comprehensive baseline risk assessment (BRA) addressed the OU1 wetland area. It was conducted
assuming a cap over the landfill was in place and fully functioning. Human exposure pathways evaluated in the
risk assessment included incidental ingestion and dermal contact of surface soil and sediment and subsistence
consumption of fish and shellfish.3 The BRA identified elevated site risks associated with adult ingestion of
shellfish living in sediment around the landfill. The primary contaminant of concern (COC) in sediment related to
human consumption of shellfish was arsenic.
The 1997 BRA also identified ecological risks associated with sediment in some tidal channels around the landfill
and with wetland soil near the leachate seeps on the landfill berm. Table 1 identifies off-source COCs in sediment
and soil. The results of the BRA served as the basis for action at the OU1 wetlands, addressed in the 1998 Record
of Decision (ROD) for the Site.
Table 1: Off-Source (OU1) COCs, by Media
Mi'rihi
COCs
Tidal Channel
Sediment
arsenic, chromium, phenol, 4-methylphenol,
fluoranthene, pyrene
Wetland Soil
aluminum, arsenic, chromium, manganese
Source: Table 1, Off-Source Contaminants of Concern, Site's 1998
ROD.
1 The parties in the Administrative Order on Consent included Seattle Disposal Company, Marine Disposal, Josie Razore,
John Banchero, Washington Waste Hauling and Recycling, Inc., Rubatino Refuse Removal, Inc., Monsanto Company and
the Port of Seattle.
2 Tables 6-2 through 6-5 in the Site's 1996 Interim Record of Decision (ROD) present summaries of on-source and off-source
site data that exceed human health and ecological comparison criteria. The 1996 Interim ROD did not select contaminants of
concern (COCs).
3 Surface water was not a medium of concern for the off-source area due to the low levels of contaminants detected, and
because the landfill cap was expected to eliminate transfer of contaminants of potential concern from the source to surface
water. Groundwater was not a medium of concern in the BRA because it is not hydraulically connected to aquifers used for
drinking water, and because the interim containment remedy was expected to eliminate the discharge of contaminated
groundwater to surface water by way of leachate seeps.
7
-------
Response Actions
Interim Remedy - OU2 Landfill
The Site's 1996 Interim ROD selected capping as the remedy for the OU2 landfill. The remedy was designed to
protect human health and the environment by containing and preventing contact with landfill waste. The landfill
cap was anticipated to eliminate leachate generation and discharge from the landfill within a few years following
its completion, and thereby reduce contaminant loadings to the off-source area.
The remedial action objectives (RAOs) for the OU2 landfill remedy are:
• Zone 1 groundwater (leachate): eliminate migration of leachate that exceeds surface water applicable or
relevant and appropriate requirements (ARARs) from, through and under the source area berm.
• Soil/landfill contents/on-source surface water: prevent direct contact with, and ingestion of, landfill
contents, contaminated soils and contaminated surface water on the landfill surface.
• Minimization of infiltration: minimize infiltration into the landfill wastes and resulting contaminant
leaching to groundwater.
• Zone 2 groundwater (native aquifer): minimize migration of contaminated groundwater at levels
exceeding surface water ARARs and prevent use of contaminated groundwater.
• Stormwater runoff and erosion: prevent detrimental impact to adjacent off-source wetlands and surface
water bodies due to stormwater runoff from the landfill cap surface.
• Landfill gas: prevent inhalation and release of landfill gas exceeding ambient air standards established by
the Puget Sound Air Pollution Control Authority. Manage landfill gas to prevent stress on a cap system.
• Wetlands: minimize loss of off-source wetlands and mitigate any destruction of or damage to off-source
wetlands from the remedial action.
• Future land use: provide final surface conditions suitable for all-season subsistence (i.e., hunting and
fishing), recreational, and light industrial and commercial uses.
The 1996 Interim ROD stated that the point of compliance for Zone 1 groundwater (the leachate seeps) shall be
the point at which leachate exits the exterior face of the perimeter landfill berm, which defines the landfill
boundary. The point of compliance for Zone 2 groundwater shall be the location where Zone 2 groundwater
discharges to surface water. The 1996 Interim ROD did not identify RAOs, points of compliance or monitoring
requirements for Deeper Zone groundwater.
The interim remedy included the following major components:
• Capping of the landfill in accordance with Washington State Minimum Functional Standards for landfill
closure.
• Installing a landfill gas collection system and, if necessary, an active gas treatment system.
• Post-construction care of the final landfill cover.
• Post-construction monitoring, including sampling of perimeter leachate seeps and monitoring of the
leachate mound and landfill gas.
• Implementation of institutional controls to restrict land use, prohibit activities that could interfere with
performance of the selected remedy, and prevent use of contaminated groundwater.
The 1996 Interim ROD stated that, because the selected remedy was expected to effectively contain the landfill
wastes by minimizing the migration of leachate away from the landfill, and because EPA did not expect that
additional future actions would be necessary to remediate Zone 2 groundwater, EPA concluded that post-
construction data collection from the Zone 2 aquifer was unnecessary. However, the Interim ROD noted that EPA
may require more monitoring to assess or ensure the short-term and long-term effectiveness and protectiveness of
the selected interim remedy.
The 1996 Interim ROD did not select specific numeric cleanup standards for any medium. However, it identified
surface water ARARs for leachate and groundwater discharging to surface water at the Site. These ARARs are
identified in Appendix I, Table 1-1, and discussed in the Technical Assessment section of this FYR Report.
8
-------
Final Remedy - OU1 Wetlands and OU2 Landfill
EPA selected a final remedy for the OU1 wetlands and OU2 landfill in the Site's 1998 ROD. It stated that the
final remedy for the landfill is the capping remedy previously documented in the Site's 1996 Interim ROD.
The RAOs for the OU2 landfill did not change from the RAOs in the 1996 Interim ROD. The 1998 ROD
identified more RAOs for the OU1 wetlands remedial action:
• Minimize human consumption of fish/shellfish that contain contaminants that result in an elevated
potential risk.
• Minimize potential for arsenic-contaminated soil surrounding the leachate seeps from acting as a
continuing source of arsenic in off-source sediment.
• Minimize potential for benthic organisms to contact sediment that exceeds cleanup screening levels
(CSLs) without physically destroying wetland habitats.
• Minimize potential for terrestrial ecological receptors to contact soil containing arsenic, manganese and
chromium at concentrations significantly greater than background concentrations.
• Minimize physical impacts to and loss of off-source wetlands.
The remedy for the OU1 wetlands is institutional controls and relies on implementation of the on-source remedy.
It includes maintenance of existing signs and, as necessary, posting of new signs along the perimeter of the
sloughs and landfill warning of the potential risk from harvesting and eating fish and shellfish. The selection of
this remedy assumed the completion of the landfill remedy. The selected remedy also called for site inspections to
ensure the warning signs were still in place and readable. Natural recovery was expected to reduce concentrations
of organic and inorganic contaminants in the tidal channel sediment. However, the 1998 ROD did not require
long-term monitoring in the wetlands; it noted that periodic monitoring of the impacted sediment and seep soil
was already required by the 1996 Interim ROD.
The 1998 ROD identified the Washington Sediment Management Standards (SMS) as relevant and appropriate
standards for the off-source remedial action because they establish numerical values for chemical constituents in
sediments. The 1998 ROD did not identify specific numeric standards for soil or sediment in effect at that time.
Status of Implementation
In March 1998, EPA entered into consent decrees with multiple PRPs to fund and to implement the remedy.
Waste Management, Inc. and the Tribes were parties to a Consent Decree for the implementation of the remedial
action and the performance of post-cleanup operation and maintenance (O&M) activities. Waste Management,
Inc. agreed to design and construct the landfill cover system. The Tribes agreed to participate in the long-term
maintenance of the landfill cover system.
EPA, in consultation with the Tribes, approved the remedy design for the landfill's cover system in May 1998.
The remedial design determined that an active gas treatment system was unnecessary. Remedial construction
began in June 1998. It took about two years to complete. In October 2000, EPA, in consultation with the Tribes,
determined that the constructed remedy was operational and functional. Waste Management, Inc. completed the
following activities:
• Prepared a sub-base and regraded the landfill area by excavating and relocating about 440,000 cubic yards
of waste in the landfill and importing 410,000 cubic yards of clean fill.
• Constructed a passive gas collection system in the waste so that a gas treatment system could easily be
added later, if necessary.
• Placed and compacted a 12-inch foundation layer (sand) over the sub-base and gas collection system.
• Constructed a liner system over the foundation layer.
• Placed a 12-inch layer of topsoil over the liner system, constructed a surface water drainage system and
revegetated the landfill.
• Installed six piezometers to measure the leachate elevation.
• Constructed a locked gate entrance to the landfill and posted warning signs.
9
-------
EPA issued a certificate of completion in February 2001. O&M activities, including a leachate seep and landfill
gas monitoring program, began at that time. Waste Management, Inc. was responsible for O&M activities for the
first four years. The Tribes assumed responsibility for O&M activities after that time.
PRPs sampled leachate seeps for one year after completion of the cap. Results from sampling in 2001
demonstrated that the remedy had reduced or eliminated the leachate seeps and that there was limited value in
continuing seep sampling. EPA approved removal of the leachate seep sampling from the monitoring program in
April 2002. The seeps continued to be monitored for flow. In response to an issue identified in the Site's 2008
FYR Report, PRPs collected leachate seep samples in June 2008 and September 2009. Only two of the 16
inspection locations (SP-13 and SP-14) yielded enough flow for sampling. The June 2008 and September 2009
sampling results were similar to 2001 sampling results and consistent with historical seep sampling trends at the
Site. Table C-l in Appendix C includes a summary of historical leachate seep data for constituents evaluated from
1994 to 2009, compared to current surface water standards. Table C-2 in Appendix C includes a summary of the
surface water quality standards. EPA concluded in the 2013 FYR Report that further seep sampling was not
warranted.
In October 2017, EPA completed an optimization review of the Site's remedy. The review included several
recommendations to reduce the frequency of or eliminate O&M and monitoring requirements for the landfill to
reduce cost and eliminate redundancy. The review also found that limited remedy performance data had been
collected since completion of the landfill cap. The review recommended sampling OU1 tidal wetlands,
groundwater wells around the perimeter of the landfill and intertidal sediments next to the landfill.
The 2018 FYR Report noted that, in 2017, Jacobs Engineering punctured the geotextile liner of the landfill to
reduce an air-filled bulge and a liquid-filled bulge in the liner on the perimeter of the landfill. During a site
inspection in November 2022 as part of a forthcoming Optimization Study for the Site, U.S. Army Corps of
Engineers (USACE) personnel determined that the punctured liner had not yet been repaired and must be covered
by riprap to protect the liner.
The 2018 FYR Report recommended sampling groundwater beneath the landfill (OU2) and sampling sediment in
the wetlands and intertidal areas of OU1 to evaluate remedy protectiveness. The 2018 FYR Report deferred
issuing a protectiveness determination until the information was obtained. Prior to sampling, EPA determined that
a review of available data should be conducted. The Existing Data Review for the 2018 Five-Year Review (2020
Technical Memorandum), prepared by CH2M HILL Engineers, Inc., and included as an attachment to EPA's
2020 FYR Addendum Report, documents the review of available data. Based on the review, EPA determined that
more sampling was not warranted. EPA documented the finding in the 2020 FYR Addendum Report.
2020 Technical Memorandum
In the 2018 FYR Report, EPA recommended sampling groundwater beneath the landfill (OU2) as well as
sampling sediment in intertidal areas of OU1 and evaluating the data relative to the protectiveness of the remedy.
As part of planning for the sampling, EPA determined that a review of available data should be conducted prior to
sampling. The 2020 Technical Memorandum, prepared by EPA contractor CH2M Hill Engineers, Inc., compiles
and evaluates available existing data for the Site and surrounding areas.
The review determined that the most recent sediment data near the Site are from a 2009 study conducted by
Ecology. Based on review of the 2009 data, the 2020 Technical Memorandum concluded that sediment impacts in
OU1 previously identified during the RI do not appear to extend beyond the OU1 wetlands and into the adjacent
sloughs. The memorandum, however, did not present information to confirm natural attenuation of contaminants
in sediment.
For OU2 (landfill), remedy effectiveness was assessed using available site data on the leachate (Zone 1
groundwater) elevations and leachate seeps from the landfill. A review of the quarterly monitoring data for
leachate levels and leachate elevations showed that levels declined consistently after completion of the cap in
2001. No active seeps had been observed at the Site since October 2016, with only minimal flow (<0.5 gallons per
10
-------
minute) observed since 2006.4 The installation and ongoing maintenance of the landfill cap and vegetated cover
appear to have eliminated the seeps based on the visual inspections.
Institutional Control (IC) Review
The 1996 Interim ROD required institutional controls to restrict land use, prohibit activities that could interfere
with performance of the selected remedy, and prevent use of contaminated groundwater.
Several layers of institutional controls are in place at the Site (Table 2). The Tribes zoned the landfill portion of
the Site for industrial uses and the wetlands, west of the berm, as a conservation area. The 1994 Tulalip
Comprehensive Plan, updated in 2009, indicates that designation of land as conservation land is intended to
preserve and protect areas of unique value. Except for utility crossings, no development is allowed in a designated
conservation area. Informational controls are also in place for the OU1 wetlands. The Tribes have posted signs in
the wetlands surrounding the landfill, which face toward the wetlands, warning of the potential risk from
harvesting and eating fish and shellfish near the Site. Figure 2 shows site parcels as well as the locations of the
warning signs.
In March 1998, the Tribes submitted a copy of the March 1998 Consent Decree to the Northwest Regional Office
of the Bureau of Indian Affairs. The Bureau of Indian Affairs recorded the Consent Decree in the land records of
the U.S. Department of the Interior Title Plant. The filed document provides public notice of access and
institutional control requirements at the Site.
The Tribes also prepared the Routine Use of the Tulalip Landfill document, dated February 2002. In the cover
letter to this document, the Tribes stated that they wished to leave the Site idle so that the remediation could
mature, and that they preferred to delay the identification of any specific reuse for the Site. The document
provided a process that the Tribes would follow to identify future land uses for the Site and to secure EPA's
written approval for any change in use. The document also clarified that uses penetrating the surface of the cover
system would not be permitted. The Tribes are evaluating the possibility of installing a solar installation on the
Site.5
The Tribes passed a resolution in April 2013 providing for enforcement against any person entering the Site
(referred to as the Big Flats property) without proper authorization from the Tribes, or any person engaging in
prohibited activities.
Although the 1996 Interim ROD required land use and groundwater use restrictions on the landfill property to be
in place as covenants running with the land, EPA believes that such covenants are unnecessary. Groundwater at
the Site is brackish and unusable as a potable water source. The institutional controls in place are adequate and
appropriate for protecting human health and the environment at the landfill and wetlands.
The 2018 FYR Report raised the question as to whether perimeter signs are still needed for the wetlands. EPA re-
evaluated the institutional controls at the Site as part of the 2020 FYR Addendum Report. EPA determined, based
on review and evaluation of the data and existing institutional controls, that it was not necessary to change the
institutional controls at that time.
4 Since the 2020 Technical Memorandum, flow was observed at seep location SP-4 during the 2021 annual inspection. It is
believed the flow observed was related to a rain event prior to and during the inspection. Active seeps were not observed in
any subsequent quarterly monitoring event.
5 The Tulalip Landfill 1st Semi-Annual Memorandum of 2022 noted that the Tribes are working with the Snohomish County
Public Utility District (SnoPUD) to determine the best options for a solar farm and energy storage capacity. A System Impact
Study is underway. SnoPUD recently received a $150,000 Clean Energy Fund Grant to support potential energy storage
facilities at the landfill.
11
-------
Table 2: Summary of Planned and/or Implemented Institutional Controls (ICs)
Mediii.
l-ln^ineered
( ontrols. iiiid
Areas Ihiil Do
No( Support
I 1 /I 1 Bused
on Ciirrenl
Conditions
ICs
Needed
ICs Culled
lor in llie
Decision
Documents
Impueled
P;ireel(s)
IC
OI).jee(i\e
Tide of l( Inslriinienl
Implemented ;ind
Diile
OU2 (landfill)
Yes
Yes
30053200100300,
30053200400100,
30053200400200,
30053200400300,
30053200400400,
30053200300100,
30053200300200
To ensure continued
effectiveness of the
interim remedial action
and to prevent human
exposure to
contamination
remaining at the Site at
concentrations above
health-based risk levels.
To limit or prohibit
activities that could
interfere with the
performance of the
selected remedy.
Routine Use of the
Tulalip Landfill
document, dated
February 2002
Consent Decree, filed
with the Bureau of
Indian Affairs office,
March 1998
Tulalip Official Zoning
Map, Tulalip Indian
Reservation, adopted
December 1994 and
readopted January 1995
Tribe resolution
8.20.361, Unauthorized
Entry or Activities on
Big Flats Restricted
Lands, dated April
2013
OU1
(wetlands)
Yes
Yes
29050500101000,
29050500200400,
30053200100300,
30053200300100,
30053200300200,
30053200300300,
30053200300400,
30053200400100,
30053200400200,
30053200400300,
30053200400400,
30053300203800,
30053300300100,
30053300300200,
No Parcel ID
To prohibit access to
contaminated wetlands
and the consumption of
fish and shellfish from
those areas.
Warning signs posted in
wetlands surrounding
the landfill
Tulalip Official Zoning
Map, Tulalip Indian
Reservation, adopted
December 1994 and
readopted January 1995
(applicable to parcels
owned by the Tribes
only)
Tulalip Comprehensive
Plan (updated 2009)
Notes:
Most of the Site, including the landfill, is held in trust by the United States for the benefit of the Tribes. The easterly portions of the
Site, comprised mostly of the wetlands between the easternmost landfill berm and Interstate 5, is held under private or state
ownership (i.e., parcels 30053300203800, 30053300300100, 30053300300200) (Figure 2). Ownership and parcel information from
the Snohomish County Geographic Information System, available at
httDs://scoDi.snoco.ora/Html5Viewer/Index.html?confiaBase=httDs://scoDi.snoco.ora/Geocortex/Essentials/REST/sites/SCOPI/vie
wers/SCOPI/virtualdirectorv/Resources/Confia/Default accessed October 14, 2022.
12
-------
N Tulalip Landfill Superfund Site
A City of Marysville, Snohomish County, Washington
Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding EPA's
response actions at the Site. Map image is the intellectual property of Esri and is used herein
under license. Copyright © 2020 Esri and Its licensors. All rights reserved. Sources: Esrl, Maxar,
Snohomish County, the 2017 Quarterly Report, the 2018 FYR Report and the 2021 Annual Site
Inspection Memorandum.
Last Modified: 12/16/2022
Figure 2: Site Parcel Mai
30053300300100
30053200100300
30053300203800
30053200400100
'30053200400400
30053200300300
30053200300200
v -X \
(No
Parcel
' ID)
30053300300100
30053200400200
30053200300100
30053200400300
\ \ \ \ v
29050500200400
\ \ \ \N
29050500101000
30053300300200
30053200300400
Approximate Site Boundary
OU1 (Wetlands)
OU2 (Landfill)
Parcel Boundary
Perimeter Warning Sign
13
-------
Systems Operations/Operation and Maintenance (O&M)
The Tribes perform O&M activities in accordance with the Site's 2001 Operations and Maintenance Manual, as
updated by the 2016 Big Flats Operations and Maintenance Manual (2016 O&M Manual). Routine O&M
activities include inspections and maintenance of the landfill cover system, settlement surveys and aerial surveys.
The Tribes also implement a landfill gas, leachate and seep monitoring program. Figure 3 shows the locations of
the landfill gas vents, piezometers and seep monitoring locations. In 2021, the Tribes added a mobile office trailer
at the landfill, near the goat and llama storage area. As of October 2022, the mobile office trailer was empty and
not in use. Two full-time employees with the Tribes manage O&M activities at the landfill.
During quarterly O&M inspections, the Tribes and its contractors evaluate the condition of the following system
components: landfill grades, surface water control systems, cover soil, vegetation, the infiltration collection
system, access roads, the gas collection system, perimeter slope protection, piezometers, security and signs.
Routine O&M activities also include mowing of the vegetative cap, weed control (removing invasive scotch
broom and blackberries), fixing of animal holes and llama-damaged areas, maintenance of gas vents and
piezometers, clearing of drainage outlets, and repair and replacement of perimeter warning signs. Previously, a
herd of goats and llamas were on site for supplemental vegetation control in areas inaccessible to mowers.
However, it was suspected that the animals were damaging the cap. EPA instructed the Tribes to remove all
animals off the premises by 2022. As of October 2022, the goat population has decreased to two goats and the
llama population has decreased to one llama.
In addition to routine O&M activities, the Tribes conduct an annual site inspection and settlement survey and an
aerial/topographic survey every three years to measure the slope of the cap. An aerial survey in 2019 found the
landfill cap was in good condition.
The Tribes also implement a monitoring program that includes three main components:
• Quarterly monitoring of landfill gas at six passive gas vents (GVS-1 through GVS-6).
• Quarterly monitoring of leachate elevations inside the waste control area using five piezometers (PZ-1
through PZ-5).
• Quarterly visual inspection of 16 potential leachate seep locations around the perimeter of the landfill.
Most of the seeps have been dry since the installation of the landfill cap system. The 2016 O&M Manual
requires collection of samples from any seeps with flow. Seeps were last sampled in 2009.
The Tribes submit the inspection and monitoring results to EPA semi-annually and annually.
In the Site's 2020 and 2021 annual inspection reports, the most recent annual reports available for review, the
Tribe's inspection contractor, Jacobs Engineering Group, Inc. (Jacobs), noted that, overall, the landfill continues
to be well maintained, surface slopes are acceptable, and the cover is functioning as designed. Asymptotic or near-
asymptotic settlement trends continue in all areas. The Tribes make improvements each year based on
recommendations in the annual inspection reports.
The 2021 Annual Inspection Report included the following recommendations, with the first three items identified
as critical recommendations:
• Outfit a fuel tank observed near the goat and llama shelter/storage unit with secondary containment.
• Inspect seep location SP-4 for flow during dry weather conditions and report findings to EPA and Jacobs.
During the 2021 annual inspection, conducted on a rainy day and just after two days of rain, flow was
observed at SP-4.6
• Continue aggressive use of herbicide and manual removal of invasive plants (blackberry and Scotch
broom), especially along perimeter roads, interior berms and riprap armor.
• Complete thorough flushing of all lateral drainage lines and investigate and eliminate potential blockages
in storm water drainage laterals B2, El, E2, Fl, F2,12, LI, L2, M2 and PI.
• Repair the chain-link fence entry gate with metal components rather than plastic components.
6 During first and second quarter monitoring in 2022, SP-4 was again dry.
14
-------
• Re-brace or re-install perimeter warning signs that are leaning or missing (one sign was observed missing
in 2021).
• Organize equipment and storage containers and remove litter.
• Complete an inspection of all existing rain barrels, identifying and replacing any cracked or broken
barrels (the inspection report identified several that needed replaced).
• Replace or repair the lids of piezometers PZ-2 and PZ-3.
• Consider replacement of the vertical landfill gas (LFG) risers at GVS-5 and GVS-6 if further warping
occurs.
• Clean the louvers at the top of each LFG vent to ensure venting is not restricted.
• Spread gravel inside and around the chain-link fence at each LFG vent to mitigate vegetation growth.
• Address action items related to storm water discharge points.
• Replenish riprap and monitor the localized slope failure at the riprap/asphalt transition near H1/H2 and
H3/H4.
• Monitor the slope failure in the riprap near P1/P2.
• Cease the annual settlement surveys and cease the triennial aerial topographic remapping. Visually
monitor the cover for evidence of settlement.
EPA is in the process of assessing the Site to determine possible updates to the O&M Manual. EPA continues to
be concerned about the annual O&M and staffing costs. US ACE is currently conducting an Optimization Study to
conduct a post-closure analysis of the landfill. This will determine all reasonable and necessary O&M activities
needed to ensure long-term custodial care of the remedy at the landfill and guarantee protection of human health
and the environment. This evaluation will be used by EPA to update the O&M Manual for Tulalip Landfill and
inform EPA on decisions of future annual budgets, including the necessary hours and staffing to implement the
plan.
15
-------
Figure 3: Landfill Monitoring Locations
n J ¦O!
, f VI -
n ^ f v. .;c.
^Skeo
Last Modified: 12/16/2022
N Tulalip Landfill Superfund Site
A City of Marysville, Snohomish County, Washington
i 1 1 1
n 1 nnn o nnn ** nnn Poot
Disclaimer: This map and any boundary lines within the map are approximate and subject to
change. The map is not a survey. The map is for informational purposes only regarding EPA's
response actions at the Site. Map image is the intellectual property of Esri and is used herein
under license. Copyright © 2020 Esri and its licensors. All rights reserved. Sources: Esri, Maxar,
the 2017 Quarterly Report and the 2018 FYR Report.
16
-------
III. PROGRESS SINCE THE PREVIOUS REVIEW
This section includes the protectiveness determinations and statements from the last FYR completed in April 2018
and the FYR addendum completed in May 2020 as well as the recommendations from the last FYR and FYR
addendum and the current status of those recommendations. Table 3 includes the protectiveness determinations
and statements from the 2018 FYR Report and Table 4 includes the updated protectiveness determinations from
the 2020 FYR Addendum Report. Table 5 identifies the issues and recommendations from both the 2018 FYR
Report and the 2020 FYR Addendum Report as well as the status of the recommendations.
Table 3: Protectiveness Determinations/Statements from the 2018 FYR Report
()l #
Pmieiiiu'iii'ss
IkMiTmiiiiiliun
Pmleiiiu'iii'ss M;ilcim-nl
1
Protectiveness
Deferred
A protectiveness determination of the remedy at OU1 (wetlands) cannot be made at this
time until further information is obtained. Further information will be obtained by taking
the following actions: Collect samples from the off-source tidal wetlands to determine
current concentrations and to obtain data necessary to evaluate the results in the context
of background concentrations and potential regional contaminant sources.
It is expected that this action will take approximately two years to complete, at which
time a protectiveness determination will be made.
2
Protectiveness
Deferred
A protectiveness determination of the remedy at OU2 (landfill) cannot be made at this
time until further information is obtained. Further information will be obtained by taking
the following actions: Collect groundwater samples within the refuse layer and analyze
for site COCs. Evaluate the results in the context of regional natural and anthropogenic
background concentrations.
It is expected that this action will take approximately two years to complete, at which
time a protectiveness determination will be made.
Sitewide
Protectiveness
Deferred
Because the protectiveness determinations for OU 1 and OU2 are deferred, a sitewide
protectiveness determination is also deferred until further information is obtained.
Further information will be obtained by taking the following actions: 1) Collect samples
from the off-source tidal wetlands to determine current concentrations and to obtain data
necessary to evaluate the results in the context of background concentrations and
potential regional contaminant sources. Determine if the institutional controls imposed
by the final ROD are still necessary. 2) Collect groundwater samples within the refuse
layer and analyze for site COCs. Evaluate the results in the context of regional natural
and anthropogenic background concentrations.
It is expected that this action will take approximately two years to complete, at which
time a protectiveness determination will be made.
Table 4: Protectiveness Determinations/Statements from the 2020 FYR Addendum Report
OIJ #
Pmk'iiiu'iii'ss
l)iMiTinin;iliun
Pmleiiiu'iii'ss M;ilcim-nl
1
Protective
EPA has determined that the remedy for OU 1 is protective of human health and the
environment. Threats to the wetlands have been addressed through containment of
contaminated soil and groundwater with the completion of the landfill cover system and
the implementation, monitoring and enforcement of effective ICs.
2
Protective
EPA has determined that the remedy for OU2 is protective of human health and the
environment. Threats from the landfill have been addressed through containment of
contaminated soil and groundwater with the completion and ongoing maintenance of the
cover system and implementation, monitoring and enforcement of effective ICs.
Sitewide
Protective
EPA has determined the remedy at the Tulalip Landfill Site is protective of human health
and the environment. All threats at the Site have been addressed through containment of
contaminated soil and groundwater with the completion and maintenance of the cover
system and the implementation, monitoring and enforcement of effective ICs.
17
-------
Table 5: Status of Recommendations from the 2018 FYR Report
()l #
Issiio
KcconiiiiciKliilioiis
( iinvnl
Siiiius
( iinvnl Impk-mciiliilioii
Siiiius Description
( ompk-iiun
Diilc (if
l>lic;il>k')
1
Performance
monitoring has not
been conducted in
the off-source
wetlands. Although
not required by the
1998 ROD,
monitoring is
needed to determine
if natural attenuation
has reduced residual
contamination to
acceptable levels, or
if contaminant
concentrations in
wetlands exceed
background levels.
Additionally, it is
unknown if
institutional controls
are still necessary in
the wetlands.
Collect samples
from the off-source
tidal wetlands to
determine current
concentrations and
to obtain data
necessary to
evaluate the results
in the context of
background
concentrations and
potential regional
contaminant
sources. Determine
if institutional
controls imposed
by the final ROD
are still necessary.
Considered
But Not
Implemented
EPA determined that a review of
available data should be
conducted prior to sampling. The
review of available data is
documented in the 2020
Technical Memorandum. Based
on the review, EPA determined
that more sampling was not
warranted and documented this
finding in the 2020 FYR
Addendum Report.
EPA also determined, based on
review and evaluation of the data
and existing institutional
controls, that it was not
necessary to change the
institutional controls at this time.
EPA documented this decision
in the 2020 FYR Addendum
Report.
5/14/2020
2
Groundwater data
within the refuse
layer have not been
collected to
demonstrate that the
capped landfill no
longer acts as a
source of
contamination to
groundwater and
surrounding surface
waters.
Collect
groundwater
samples within the
refuse layer and
analyze for site
COCs. Evaluate the
results in the
context of regional
natural and
anthropogenic
background
concentrations.
Considered
But Not
Implemented
As EPA began to plan for
sampling, EPA determined that a
review of available data should
be conducted prior to sampling.
The review of available data is
documented in the 2020
Technical Memorandum. Based
on the review, EPA determined
that more sampling was not
warranted and documented this
finding in the 2020 FYR
Addendum Report.
5/14/2020
IV. FIVE-YEAR REVIEW PROCESS
Community Notification. Community Involvement and Site Interviews
The results of the review and the report will be made available online at https: //www. epa. gov/superfiind/tulalip-
landfill.
During the FYR process, interviews were conducted to document any perceived problems or successes with the
remedy that has been implemented to date. The interviews are summarized below. Appendix D includes the
completed interview forms.
Big Flats landfill manager Tony Reese noted that little has changed since the previous FYR. The landfill's cap
and drainage system are working as intended. He noted that employees are on site 40 hours each week to perform
O&M activities, including mowing from March through October. The Tribes believe there should not be any
changes in O&M activities at the Site. Trespassing and vandalism are ongoing issues at the Site. Some equipment,
18
-------
including a skid-steer and flatbed, tools, generator and air compressor were stolen recently. Graffiti was also
painted near the entrance.
Evan Griffiths with Jacobs (O&M contractor) noted that the Site is in good shape, with minor maintenance issues
that are addressed quickly by tribal staff. He was unaware of any significant issues or changes in O&M
requirements or schedules.
Data Review
This data review evaluates landfill gas, leachate and seep monitoring data collected as part of long-term
monitoring requirements identified in the 1996 Interim ROD and presented in 2018 to 2022 quarterly post-closure
monitoring reports. The data review also summarizes annual survey data presented in the 2021 annual site
inspection technical memorandum.
Landfill Gas Monitoring
The Tribes' contractor monitored landfill gas at gas vents GVS-1 through GVS-6 quarterly between 2018 and the
third quarter of 2022. Gas composition results indicate that the landfill gas (expressed as combined methane and
carbon dioxide) is generally present most of the time in all landfill gas vents. Table 6 summarizes the range of
detected methane and carbon dioxide during this FYR period. Figures E-l and E-2 in Appendix E show historical
methane and carbon dioxide concentrations for each gas vent. The figures show more steady gas production over
the last decade of monitoring. The Post Closure Monitoring Report for the second quarter of 2022 states that
concentrations of methane and carbon dioxide remain within the ranges of declining landfill gas production.
The Tribes' contractor also monitored trace compounds, including hydrogen sulfide, carbon monoxide and
volatile organic compounds (VOCs), quarterly during the FYR period, using portable instruments. Hydrogen
sulfide was periodically detected in all six gas vents, with a maximum detection of 18.7 parts per million (ppm) in
GVS-1 in October 2019. Carbon monoxide was typically not detected. VOCs were sporadically detected at low
levels (below 7 ppm).
The 1996 Interim ROD states that air emissions will not exceed ambient air standards established by the Puget
Sound Air Pollution Control Authority (now known as the Puget Sound Clean Air Agency) requirements. In
November 2000, a letter from SCS Engineers to Waste Management, Inc. documents landfill gas emissions
comply with the requirements and that treatment was not needed.
Table 6: Range of Detected Methane and Carbon Dioxide in Landfill Gas Vents, 2018 to 2022a
Year
Kaii^c of IK'k'Ck'd Mclhanc
( V'ii l)\ \ (llllllio)
Kiinuo of IK'k'Ck'd ( arhon Dioxide
(V'ii l)\ \olllllH')
:uis
44.1 09.3
""" "
2019
57.8-65.8
0.1-41.5
2020
52.3 -66.3
30.5-47.7
2021
23.5-70.0
26.4-51.9
2022b
59.5 -68.2
31.8-41.1
Notes:
a) Source: Excel spreadsheet of data, provided by EPA. Only non-zero values are reported.
b) Data from January 2022 through August 2022 only; fourth-quarter 2022 data were not yet available for
review.
Leachate Monitoring
The Tribes' contractor monitored leachate levels at piezometers PZ-1 through PZ-5 from 2018 through the second
quarter of 2022. Although there are slight variations in the leachate elevations, the leachate levels generally
continue their long-term decreasing trend, with decreases in leachate elevation ranging from about 6 feet to 14
feet across the Site. The results are consistent with an overall decrease in storm water infiltration into the waste
materials since the construction of the cover system. Figure E-3 in Appendix E shows historical leachate
elevations between 2001 and 2022.
19
-------
Seep Inspection and Monitoring
The Tribes' contractor visually inspected 16 potential leachate seep locations (SP-1 through SP-16), including the
10 original seeps referenced in the 1996 Interim ROD, quarterly from 2018 to the second quarter of 2022 (Figure
3). In addition, the seep locations were visually inspected during a separate annual inspection by Jacobs.
Flow was not observed at any seep location during the quarterly monitoring events from 2018 to the second
quarter of 2022. During the 2021 annual inspection by Jacobs, flow was observed at seep location SP-4. It was
raining during the inspection, and rain events had occurred in the days preceding the inspection. During the next
two quarterly monitoring events in 2022, no flow was observed at seep SP-4. Therefore, no seep sample was
collected. Construction of the final cap appears to have eliminated discharge of leachate from the landfill seeps.
Survey Data
The Tribes' contractor conducted annual settlement surveys to evaluate slope and subsidence of the landfill. The
landfill was designed to have a minimum slope of 2% after long-term settlement. Significant landfill settlement
was anticipated in the design. Therefore, when the cover was constructed, it was built with a minimum slope of
2.5% in interior fill areas and with a minimum slope of 2.2% in exterior cut areas. Figure E-4 in Appendix E
shows the settlement survey monument locations. Tables E-l and E-2 in Appendix E present the settlement data
from 2000 to 2021 for the fill and cut areas.
For the fill areas, all slopes are within the predicted settlement range and meet minimum long-term slopes of 2%,
except for the measured slope in Panel S and Panel O. The slope in Panel S (1.8 %) in the Northeastern Area has
not changed since 2017. The slope in Panel O (1.9 %) in the Southwestern Area has not changed since 2011 and is
just below the long-term target slope of 2%.
For the cut areas, all slopes are at or above the long-term target slope of 2%, except for the measured slopes in
Panel A (1.9%), Panel S (1.4%), Panel D (1.9%) and Panel Q (1.9%). The slope in Panel A is the same as in 2019
and 2020. The slope in Panel S has not changed since 2016. The slope in Panels D and Q are just below the long-
term target slope of 2%.
The intent of a minimum 2% slope is to accommodate drainage as the landfill settles over time. Therefore, if the
flatter slopes that are present still allow runoff, rebuilding the slope is not warranted at this time. However,
continuation of a monitoring and maintenance program to look for localized ponding is recommended, with filling
of any areas where ponding has occurred and grading of the filled areas to promote drainage off the cap. Ponding
was not observed in Panel S during the annual site inspection.
Site Inspection
The site inspection took place on October 10, 2022. Participants included EPA RPM Rebecca C. Feldman, Dustan
Bott with EPA, Dylan Houle and Anthony Reese from the Tribes, and Johnny Zimmerman-Ward from EPA
contractor Skeo. The purpose of the inspection was to assess the protectiveness of the remedy. Appendix F
includes photographs from the site inspection. Appendix G includes the completed site inspection checklist.
Site inspection participants met at the new office on site. It is in place, but not yet in use. Site inspection
participants drove the perimeter of the landfill and observed the wetlands, riprap, landfill cap, cleanouts, rain
barrels associated with the drainage, gas monitoring wells, piezometers, livestock, equipment and containers. The
vegetative cover was in good condition. Invasive species (blackberries) were observed along the perimeter road,
as well as in riprap. Scotch broom was also observed on a berm in the landfill. Staff indicated these species are
addressed by manual removals and mowing, as needed. Site security consists of limited access (locked gate at the
east end of the landfill), fencing and gates at the end of the entrance road, and fencing and gates around the
landfill gas venting structures. Site contamination warning signs are posted in the wetlands around the perimeter
of the Site.
20
-------
V. TECHNICAL ASSESSMENT
QUESTION A: Is the remedy functioning as intended by the decision documents?
Question A Summary:
Yes. The OU1 and OU2 remedies are functioning as intended by the decision documents.
OU1 (wetlands)
The OU1 remedy (perimeter warning signs and site inspections with an expectation for natural recovery) is
functioning as intended by site decision documents. The Tribes regularly inspect the Site and ensure that the
perimeter warning signs are in place. In response to an issue raised in the 2018 FYR Report, available
groundwater, leachate elevation, leachate seeps, sediment and surface water data were compiled and evaluated to
determine if more sampling in the wetlands was warranted. The results of the evaluation were presented in the
2020 Technical Memorandum. Based on the review, EPA determined that sediment impacts in OU1 previously
identified during the RI do not appear to extend beyond the OU 1 wetlands and into the adjacent sloughs. EPA
determined that additional sampling was unnecessary at that time. Based on further review of site decision
documents as part of this FYR, it is recognized that the alternative selected for the OU 1 remedy assumed that
sedimentation would result in natural attenuation of contaminants in the sediments and wetlands around the
landfill. The 2020 Technical Memorandum did not provide data or other information to confirm natural
attenuation. A sediment evaluation is necessary to confirm the expectation of natural recovery described in the
Site's 1998 ROD. Capping of the landfill (OU2) is expected to significantly reduce contaminant loading from the
landfill to the wetlands.
OU2 (landfill)
The landfill cover system has been in place since 2000. It effectively prevents direct exposure to waste and
minimizes the infiltration of rainwater through the waste. In turn, this prevents the formation of new leachate and
minimizes the migration of residual contaminants from the landfill to groundwater and the adjacent wetlands.
Leachate levels continue to decline overtime. However, leachate seep samples were last collected in 2009, and at
that time, samples were not analyzed for all site COCs. Seeps around the perimeter of the landfill that were active
before cap construction no longer discharge leachate. Monitored seep locations were dry during all quarterly
monitoring events during this FYR period. Flow was observed at SP-4 during the 2021 annual inspection, which
occurred during a rain event, but was dry during subsequent monitoring events. It is not believed to be an active
leachate seep. Overall, the landfill is well maintained, with a regular on-site O&M presence. Minor maintenance
issues, such as mole holes and invasive plants, are addressed as they arise. However, a November 2022 site
inspection found that damage to the landfill's geotextile liner (punctures to address bulging) originally identified
in 2017 had not yet been repaired by covering the area in riprap. Trespassing at the Site is an ongoing issue, but it
has not affected any of the remedial components. Minor settlement measured during the annual monitoring events
does not impede runoff at the landfill. The surface drainage features of the cap system are functioning as
designed. Due to the stability in site conditions over the past 20 years, EPA may consider reducing the frequency
of monitoring for certain O&M tasks, such as settlement surveys (currently annual), aerial topographic surveys
(currently triennial) and leachate, landfill gas and seep inspection/monitoring (currently quarterly) to reduce cost
and eliminate redundancy.
Institutional controls are in place for the landfill to maintain the integrity of the cover system and to restrict future
land use. Although the 1996 interim ROD required land use and groundwater use restrictions on all site property
as covenants running with the land, EPA believes the institutional controls currently in place, including tribal
zoning restrictions and implementation of the 2002 Routine Use of the Tulalip Landfill document, are adequate
and appropriate for protecting human health and the environment.
21
-------
QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of the
remedy selection still valid?
Question B Summary:
Yes. The exposure assumptions and RAOs used at the time of remedy selection are still valid. Toxicity data and
potential standards have changed since the ROD. However, these changes do not call into question the
protectiveness of the remedy because there are no exposures to contamination and institutional controls are in
place to prevent potential future exposures.
As part of this FYR, EPA conducted a review of the chemical-specific ARARs included in the site decision
documents to determine if any changes to chemical-specific standards have occurred that could affect
protectiveness of the remedy (Appendix I). The 1996 interim ROD identified federal Clean Water Act ambient
water quality criteria (AWQC) and Washington State water quality standards as chemical-specific ARARs. The
review found that 39 standards have become more stringent. The rest of the standards have become less stringent
or have not changed. These results do not affect the protectiveness of the remedy because construction of the
landfill cap system has eliminated the discharge of leachate seeps to surface water. If seep or surface water
sampling is conducted in the future, the most current standards should be considered in the evaluation of the data.
Land use on site has not changed since the previous FYR. Groundwater beneath the Site is brackish and therefore
unusable as a potable water source. Access to the Site is restricted and perimeter signs are in place to warn of the
potential risk from harvesting and eating fish and shellfish near the Site. The Tribes are currently exploring the
possibility of installing a solar installation on site. The Tribes will continue to coordinate with EPA to ensure any
redevelopment is consistent with the restrictions set forth in the institutional controls.
The remedy is progressing as expected toward meeting RAOs. However, there are no recent sediment evaluations
to determine if natural recovery for the off-source area (wetlands) has occurred. A review in 2020 of existing
sediment data (most recently collected by Ecology in 2009) provided some information, but a sediment evaluation
would provide additional information on whether the OU1 remedy is meeting the RAO to minimize the potential
for benthic organisms to contact sediment that exceeds CSLs.
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 effectiveness of the remedy.
22
-------
VI. ISSUES/RECOMMENDATIONS
Issues/Recommendations
()l (s) without Issues/Recommendations Identified in the I YR:
None
Issues :t nd Recommendations I den t i lied in the l-'Yk:
OU(s): OU1
(wetlands)
Issue Category: Remedy Performance
Issue: The remedy selected for the off-source area (wetlands) was institutional
controls with the expectation that the source remedy would eliminate further
impacts and natural recovery would occur in the tidal channel sediment. There has
not been a recent sediment monitoring to determine if natural recovery is
occurring.
Recommendation: Complete a sediment evaluation for the off-source area
(wetlands).
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
EPA
EPA
4/23/2026
OU(s): OU2
(landfill)
Issue Category: Operations and Maintenance
Issue: Damage to the landfill's geotextile liner originally identified in 2017 has
not yet been repaired. Site inspections have also identified cap maintenance issues
that have not been addressed.
Recommendation: Repair the landfill's cap maintenance issues noted in recent
site inspections.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party
Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
EPA
EPA
4/23/2026
OTHER FINDINGS
One additional recommendation was identified during the FYR. The recommendation does not affect current
and/or future protectiveness.
• EPA, in consultation with the Tribes, should determine if the implementation frequency of certain O&M
tasks can be reduced based on stable site conditions over the past 20 years. EPA's contractor visited the
Site in November 2022 and plans to make further recommendations for optimizing O&M tasks. If
changes are made, they should be documented in an updated O&M Manual.
23
-------
VII. PROTECTIVENESS STATEMENT
OUl Protectiveness Statement
Operable Unit: Protectiveness Determination:
OU1 Short-term Protective
Protectiveness Statement: The remedy for OUl (wetlands) is currently protective of human health and
the environment. Threats to the wetlands have been addressed through containment of waste,
contaminated soil and groundwater with the completion of the landfill cover system and the
implementation, monitoring and enforcement of institutional controls. However, in order for the
remedy to be protective in the long term, the following action needs to be taken to ensure
protectiveness: complete a sediment evaluation for the off-source area (wetlands).
OU2 Protectiveness Statement
Operable Unit: Protectiveness Determination:
OU2 Short-term Protective
Protectiveness Statement: The remedy for OU2 (landfill) is currently protective of human health and
the environment. The landfill cover system prevents direct exposure to contamination and limits
migration of contaminants into groundwater and the adjacent wetlands. A long-term monitoring
program and institutional controls are in place and effective. However, in order for the remedy to be
protective in the long term, the following action needs to be taken to ensure protectiveness: repair the
landfill's geotextile liner and resolve other cap maintenance issues noted in recent site inspections.
Sitewide Protectiveness Statement
Protectiveness Determination:
Short-term Protective
Protectiveness Statement:
The Site's remedy currently protects human health and the environment. The landfill cover system
prevents direct exposure to contamination and limits migration of contaminants into groundwater and
the adjacent wetlands. A long-term monitoring program and institutional controls are in place and
effective. However, in order for the remedy to be protective in the long term, the following actions
need to be taken to ensure protectiveness: 1) complete a sediment evaluation for the off-source area
(wetlands) and 2) repair the landfill's geotextile liner by covering with riprap and resolve other cap
maintenance issues noted in recent site inspections.
VIII. NEXT REVIEW
The next FYR Report for the Tulalip Landfill Superfund site is required five years from the completion date of
this review.
24
-------
APPENDIX A - REFERENCE LIST
Addendum to the Fourth Five-Year Review Report for Tulalip Landfill Superfund Site, Snohomish County,
Washington. EPA Region 10. May 2020.
Big Flats Operations and Maintenance Manual. CH2MHill. June 2016.
Final Record of Decision, Tulalip Landfill Superfund Site On-Source and Off-Source Remedial Action. EPA
Region 10. September 1998.
Fourth Five-Year Review Report for Tulalip Landfill Superfund Site, Snohomish County, Washington. EPA
Region 10. April 2018.
Optimization Review, Tulalip Landfill Superfund Site, Tulalip Indian Reservation, Marysville, Snohomish
County, Washington. U.S. Army Corps of Engineers in support of EPA. October 2017.
Post Closure Quarterly Monitoring Reports, Tulalip Landfill Superfund Site, Snohomish County, Washington.
PES Environmental Inc. 2019 to 2022.
Record of Decision, Tulalip Landfill Superfund Site Interim Remedial Action, Marysville, Washington. EPA
Region 10. March 1996.
Remedial Action Report, Landfill Cover System. SCS Engineers. November 2000.
Routine Use of the Tulalip Landfill. Tulalip Tribes. February 2002.
Second Five-Year Review Report for Tulalip Landfill Superfund Site, Marysville, Snohomish County,
Washington. EPA Region 10. April 2008.
Technical Memorandum: Existing Data Review for the 2018 Five-Year Review Tulalip Landfill Site. CH2M Hill
Engineers, Inc. March 20, 2020.
Third Five-Year Review Report for the Tulalip Landfill Superfund Site, Snohomish County, Washington. EPA
Region 10. April 2013.
A-l
-------
APPENDIX B - SITE CHRONOLOGY
Table B-l: Site Chronology
I.mmH
Diilc
The Seattle Disposal Company operated the landfill
1964 - 1979
EPA completed the preliminary assessment/site investigation
August 1988
EPA signed an Administrative Order on Consent with PRPs to conduct the Site's
remedial investigation/feasibility study (RI/FS)
August 1993
EPA listed the Site on the NPL
April 1995
The PRPs completed the RI/FS
EPA issued the Interim ROD for the landfill
March 1996
The PRPs began the remedial design
August 1997
EPA signed a Consent Decree with Waste Management, Inc. and the Tribes
March 1998
The PRPs completed the remedial design and began the remedial action
May 1998
The PRPs began construction for the remedial action (landfill cap system)
June 1998
EPA issued the final ROD
September 1998
EPA issued the Site's Preliminary Close-Out Report
Remedy construction finished
September 2000
The PRPs submitted the Remedial Action Report and began landfill monitoring
February 2001
EPA issued the Site's Final Close-Out Report
January 2002
EPA deleted the Site from the NPL
September 2002
EPA issued the Site's first FYR Report
April 2003
Waste Management, Inc. transferred O&M responsibilities to the Tribes
July 2004
EPA issued the Site's second FYR Report
April 2008
EPA issued the Site's third FYR Report
April 2013
EPA completed a remedy optimization evaluation
October 2017
EPA issued the Site's fourth FYR Report
April 2018
EPA issued an Addendum to the fourth FYR Report
May 2020
B-l
-------
APPENDIX C - HISTORICAL LEACHATE SEEP ANALYTIC AL DATA
Table C-l: Leachate Seep Analytical Data, 1994 to 2009
Location ID
SP01
SP01
SP01
SP02
SP02
SP03
SP03
SP03
5P03
SP03
SP04
SP04
SP04
SP05
SP05
SP05
SP05
SP05
Sample Date
Mar-94
May-94
Dec-94
Mar-94
Dec-94
Mar-94
May-94
Jul-94
Sep-94
Dec-94
Mar-94
May-94
Dec-94
Mar-94
May-94
Jul-94
Sep-94
Dec-94
Chemical
Units
2019 ARAR1
Ammonia
mg/L
0.035*
Cyanide
mg/L
Totol Metals
Copper
mg/L
0.0031s
Lead
mg/L
0.0081s
Mercury
mg/L
0.000025s
Nickel
mg/L
0.0082s
Zinc
mg/L
0.081s
Polychlorinated Biphenyls
Aroclor-1016
Mg/L
-
Aroclor-1221
Mg/L
-
Aroclor-1232
Mg/L
-
Aroclor-1242
Mg/L
-
Aroclor-1248
Mg/L
-
Aroclor-1254
Mg/L
-
Aroclor-1260
Mg/L
-
Pesticides
4,4'-DDD
Mg/L
0.0000079d
4,4'DDE
Mg/L
0.00000088"
4(4'-DDT
Mg/L
0.0000012d
Aldrin
Mg/L
0.000000041"
alpha BHC
Mg/L
0.000048"
alpha Chlordane
Mg/L
0.000022d
beta BHC
Mg/L
0.0014°
delta BHC
Mg/L
Dieldrin
Mg/L
0.00000007"
Endosulfan 1
Mg/L
¦f
Endosulfan II
Mg/L
10d
Endosulfan Sulfate
Mg/L
10c
Endrin
Mg/L
0.0023
Endrin Aldehyde
Mg/L
0.035c
Endrin Ketone
Mg/L
-
gamma BHC (lindane)
Mg/L
0.016b
gamma Chlordane
Mg/L
-
Heptachlor
Mg/L
0.0063
Heptachlor Epoxide
Mg/L
0.0000024d
Methoxychior
Mg/L
0.02"
Toxaphene
Mg/L
0.0000323
0.269
0.01 u
0.01 u
0.0062 UB 0.0078
0.0528 S 0.0658
0.0001 U 0.0001 u
0.0234 0.025
0.062 JE 0.0528
0.19 RU
0.19 RU
0.019 RU
0.0094 RU
0.0094 RU
0.0094 RU
0.027
0.19 RU
0.19 RU
1.2 JP
0.19 UJ
0.019 RU
0.009 RU
0.019 UJ
0.01 UJ
0.009 RU
0.009 RU
0.01 UJ
0.01 UJ
0.01 U
0.0189 UJ* 0.0067 UB
0.0618 JN* 0.0735 J*
0.00015 RUN 0.0001 U
0.0254 0.0105 B
0.0962 0.0743 UJE
0.19 UJ
0.19 UJ
0.019 UJ
0.0094 UJ
0.012
0.0426
0.01 U
0.0094 RU
0.0094 UJ
0.66 JP
0.19 UJ
0.01 UJ
0.01 UJ
0.01 U
0.0188 UB 0.0166
0.0898 0.106 0.111
0.00018 B 0.0001 U 0.0001 U
0.021 0.0176 B 0.0161 B
0.198 J* 0.0901 JE 0.0668
0.19 RU
0.19 RU
0.19 RU
0.19 RU
0.0094 RU
0.025 JP
0.012 UJ
0.023
0.131
0.00014 U
0.0205
0.11
0.19 RU
0.19 RU
0.019 UJ 0.019 RU 0.019 RU
0.01 UJ 0.017 JP 0.01 RU
0.01 RU
0.01 RU
0.023
0.02 JP
0.009 RU
0.009 RU
0.02 J
0.19 RU
0.19 RU
0.019 RU
0.009 RU
0.009 RU
0.032 PJ
0.016
0.01 U
0.0316 0.0282 J* 0.0121 U
0.138 0.159 JN* 0.0612
0.000019 UJN 0.00015 RUN 0.0001 U
0.0236 0.0212 0.0048 B
0.126 0.13 0.0364 UJE
0.19 UJ
1.2 J
0.19 UJ
0.19 UJ
0.019 UJ
0.009 UJ
0.019 UJ
0.0094 UJ
0.019 I
0.009 UJ
0.009 UJ
0.0094 UJ
0.023 JP
0.01 U
0.0124
0.0435
0.0001 u
0.0035 B
0.031
0.19 RU
0.19 RU
0.01
0.55 J
0.19 UJ
0.019 RU
0.009 RU
0.019 UJ
0.01 UJ
0.009 RU
0.009 RU
0.01 UJ
0.01 UJ
0.01 U
0.0261 J* 0.0143 U
0.113 JN* 0.0776
0.00015 RUN 0.0001 U
0.0093 UB 0.0095 B
0.0871 0.0587 JE
0.19 RU
0.19 RU
0.01 UJ
0.0326
0.257
0.0001 u
0.0143 B
0.169
0.19 RU
0.19 RU
0.019 RU
0.0094 RU
0.0094 RU
0.029 JP
0.031 J
0.0481
0.289
0.00014 U
0.023
0.194
0.19 RU
0.19 RU
0.019 RU
0.009 RU
0.009 RU
0.009 RU
0.01 U
0.0594
0.36
0.00019 U
0.0296
0.0555
0.19 UJ
0.19 UJ
0.016
0.0621 J*
0.203 JN*
0.00015 RUN
0.0212
0.126
0.19 UJ
2.6 J
0.036 JP
0.01 RU
0.019 RU
0.009 UJ
0.01 RU
0.033 JP
0.009 RU
0.064 PJ
0.019 UJ
0.01 UJ
0.024 J 0.019 UJ
0.01 UJ
0.01 UJ
C-l
-------
Location ID
SPOS
Mar-94
SPGS
May 94
SP06
Mm
SP06
Sep-94
STO6
Dec-94
SP07
Mar 94
STO?
May 94
SPOS
Mar-94
spm
May n j
0.0028 u
0.19 RU
0.19 RU
0.0052 UJB* 0.0024 U
0.0042 UJN*
0.00015 ftiiN
0.003b UB
0.0189 UB
0.19 Ui
0.19 Ui
0.19 Ui
1,7 J
0.19 RU
0,19 RU
0.19 Ui
0.19 Ui
0.19 Ui
0.19 UI
0.2 UJ
1.4 J
4,4' DDE
4,4"-DDT
afpteaHC
J(. > J I rHj<
beta BHC
U8/L
yg/t-
us/t
ug/i
0.00000/9°
000000088'
0 0000012'
0.000000041°
G.OS»22s
0.0014a
0.019 RU
0.009 RU
0.019 RU
0.009 RU
0.019 Ui 0.019 ID
G.Q1 Ui 0.0094 UJ
0.019 RU 0.02 UJ
0.009 RU 0,0093 UJ
0.019 Ui
0.009 Ui
0.01S Ui
0.01 Ui
0.019 UI
0009 UJ
0.019 RU
0,009 RU
0.019 Ui 0.02 UJ
0.01 UJ 0.01 Ui
Endosuif mi SuSfaJe
Efidrin Aldehyde
L iJti i >
-------
Location ID
SP10
SP10
SP11
SP11
SP11
SP12
SP12
SP13
SP13
SP13
SP13
SP13
SP14
Sample Date
Mar-01
Sep-Ol
Mar-94
May-94
Dec-94
Mar-01
Sep-01
Mar-01
Jul-01
Dec-01
Jun-08
Sep-09
Mar-01
Chemical
Units
2019 ARARJ
General Chemistry
Ammonia
mg/L
0.035*
0.1
u
0.18
1.437
9.286
0.144
2.4
4.6
0.74
0.1
U
0.1
U
0.63
1
0.08 J
1
Cyanide
mg/L
-
0.01 u
0.01 u
0.01 U
0.015
0.01
U
0.01 u
0.01 U
0.011
0.01
u
0.005 U
0.01 U J
0.01
U
Total Metals
Copper
mg/L
0.0031*
0.01
U
0.0375
0.0261
0.0024 Uiff
0.069 J*
0.01
U
0.0551
0.0143
0.01
U
0.01
u
0.024
0.01 U
0.01
u
Lead
mg/L
0.0081*
0.003
u
0.0152
0.0243
0.0742
0.0276 JNS*
0.003
U
0.0206
0.0035
0.003
U
0.003
u
0.07
0.002 U
0.003
u
Mercury
mg/L
0.000025*
0.0002
u
0.0002 U
0.0001 u
0.0001 U
0.00015 RUN
0.0002
U
0.0002 U
0.0002 U
0.0002
U
0.0Q02
u
0.11
0.0001 U
0.0002
u
Nickel
mg/L
0.0082*
0.04
u
0.043
0.1
0.075
0.054
0.04
u
0.0562
0.04 U
0.04
U
0.04
u
0.05
0.01 u
0.02
u
Zinc
mg/L
0.081*
0.02
u
0.0882
0.122 JE
0.106
0.1
0.02
u
0.106
0.0397
0.02
U
0.02
u
0.0005
0.034 J
0.0286
Polychlorinated Biphenyls
Arodor-1016
Mg/L
-
1
u
1 u
0.19 RU
0.19 RU
0.47 JP
1
u
1 U
1 U
1
U
1
u
1
U
1 U
1
u
Arodor-1221
Mg/L
-
1
u
1 u
-
1
u
1 U
1 U
1
U
1
u
1
u
1 U
1
u
Arodor-1232
Mg/L
-
1
u
1 u
0.19 RU
0.19 RU
0.19 UJ
1
u
1 u
1 u
1
U
1
u
1
u
1 U
1
u
Arodor-1242
Mg/L
-
1
u
1 u
-
-
1
u
1 u
1 u
1
U
1
u
1
u
1 U
1
u
Arodor-1248
Hg/L
-
1
u
1 u
-
1
u
1 u
1 u
1
U
1
u
1
u
1 U
1
u
Arodor-1254
Mg/L
-
1
u
1 u
-
-
1
u
1 u
1 u
1
U
1
u
1
u
1 U
1
u
Aroclor-1260
M€/L
-
1
u
1 u
-
-
-
1
u
1 u
1 u
1
U
1
u
1
u
1 U
1
u
Pesticides
4,4'-DDD
Mg/L
0.0000079"
0.05
u
0.05 U
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
4,4'-DDE
Mg/L
0.00000088"
0.05
u
o.os u
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
O.OS
u
4,4'-DDT
ng/L
0.0000012"
0.05
u
0.05 U
0.019 RU
0.019 RU
0.019 UJ
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Aldrin
Mg/L
0.000000041d
0.05
u
0.05 U
0.02 J
0.009 RU
0.009 UJ
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
alpha BHC
Mg/L
0.000048"
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
alpha Chlordane
Mg/L
0.000022"
0.5
u
0.5 U
-
-
-
0.5
u
0.5 U
0.5 U
0.5
u
0.5
u
0.5
u
0.5 U
0.5
u
beta BHC
Mg/L
0.0014°
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
delta BHC
Pg/L
-
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Dieldrin
Hg/L
0.00000007"
0.05
u
O.OS u
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Endosulfan 1
Mg/L
7"
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Endosulfan II
Mg/L
io"
0.05
u
0.05 U
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Endosulfan Sulfate
Mg/L
10e
0.05
u
0.05 U
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
O.OS
u
0.05 U
0.05
u
Endrin
Mg/L
0.0023
0.05
u
0.05 U
0.009 RU
0.019 RU
0.019 UJ
0.05
u
0.05 U
0.05 U
0.05
u
O.OS
u
0.05
u
0.05 U
0.05
u
Endrin Aldehyde
Mg/L
0.035'
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Endrin Ketone
Mg/L
-
0.05
u
0.05 U
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
O.OS
u
gamma BHC (lindane)
Mg/L
0.016"
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
O.OS
u
gamma Chlordane
Mg/L
-
0.05
u
0.05 U
-
-
-
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Heptachlor
Mg/L
0.0063
0.05
u
0.05 U
0.022 JP
0.009 RU
0.009 UJ
0.05
u
0.05 U
0.05 U
0.05
u
0.05
u
0.05
u
0.05 U
0.05
u
Heptachlor Epoxide
Mg/L
0.0000024"
0.05
u
0.05 U
0.0095 RU
0.009 RU
0.009 UJ
0.05
u
0.05 U
0.05 U
0.05
u
O.OS
u
0.05
u
0.05 U
0.05
u
Methoxychlor
Mg/L
0.02*
0.1
u
0.1 U
-
-
-
0.1
u
0.1 U
0.1 U
0.1
u
0.1
u
0.1
u
0.1 U
0.1
u
Toxaphene
Mfi/L
0.000032"
5
u
5 U
-
-
-
5
u
5 U
5 U
5
u
5
u
5
u
5 U
5
u
SP14
Jul-01
0,0258
0.0074
0.0002 U
0.04 U
0.0887
SP14
Dec-01
SP14
Jun-08
SP14
Sep-09
SP15
Mar-01
1 U
1 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.5 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
0.11
0.01 u
0.01 u
0.003 U
0.0002 U
0.04 U
0.02 U
1 U
1 U
1 U
1 U
1 U
1 u
1 u
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
03 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
0.15
0.005 U
0.013
0.04
0.095
0.02
0.005
1 U
1 U
1 U
1 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.5 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
0-05 UJ
0.01 UJ
0.01 U
5P15 SP15
Sep-01 Dec-01
0.01 U
0.01 J
0.002 U
0.0001 U O.0OG2 U
0.0295
0.015
0.0192
0.0092
0.01 J
0.0002 U
0.04 U 0.04 U
~.109 j 0.0765
1 U
1 U
1 U
1 U
1 U
1 u
1 u
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
03 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
1 u
1 u
1 u
1 u
1 u
1 u
1 u
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.5 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
1 u
1 u
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.5 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
0.01 U
0.003 U
0.0002 U
0.04 U
0.02 U
1 U
1 U
1 U
1 U
1 U
1 U
1 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.5 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.05 U
0.1 U
5 U
1 Selected from the most stringent water quality standards from the federal and state criteria for aquatic life
and human health.
* WAC 173-201A, Aquatic Life Criteria, Marine Chronic
" WAC 173-201A, Aquatic Life Criteria, Marine Acute
1 WAC 173-201A, Human Health Criteria for Consumption of Organisms Only
" 40 CFR 131.45, Human Health Criteria for Consumption of Organisms Only
" Section 304(a), Human Health for the Consumption of Organisms Only
Note: Shade/bold * Detected result exceeds most stringent screening value.
pg/L = microgram(s) per liter
ARAR = applicable or relevant and appropriate requirement
B = Reported value is less than the contract required detection limit (CRDL) but greater than the instrument
detection limit.
BHC = hexachlorocyclohexane
DDD = dichtorodiphenytdichloroethane
DDE = dichlorodiphenyldichloroethytene
DDT = dichlorodiphenyltrichloroethane
E «Indicates compounds whose concentrations exceed the calibration range of the method,
i = Indicates the associated result is an estimated value.
mg/L = milligram(s} per liter
P = Indicates when there is greater than 25 percent difference between the detected concentrations reported from the two g<
chromatographic columns for a pesticide/Arodor target analyte. The lower of the two values is reported as the final result
R = Indicates result was rejected during the data validation.
5 = The reported value was determined by the method of standard addition.
U - Indicates the anafyte was analyzed for but not detected.
* Duplicate analysis not within control limits.
Source: Table 4, Existing Data Review for the 2018 Five-Year Review Tulalip Landfill Site, March 2020.
C-3
-------
Table C-2: Surface Water Quality Standards
Chemical of Concern
2019 Water Quality Standards
1996 ARARs111
National Toxics Rule per WAC 173-201A
40 CFR 131.45
Section 304(a)
Aquatic Life Criteria - Marine
Human Health Criteria
for Consumption of:
Human Health for the
Consumption of
Organism Only
Human Health for the
Consumption of
Organism Only
Total Metals
Unit
Acute
Chronic
Organisms Only
Arsenic
mg/L
0.069
0.036
0.01
0.00014
0.00014
0.00014
Lead
mg/L
0.21
0.0081
-
-
-
0.0056/0.0085
Copper
mfi/L
0.0048
0.0031
-
-
-
0.0024/0.0029
Zinc
mg/L
0.09
0.081
2.9
1
26
0.076/0.086
Nickel
mg/L
0.074
0.0082
0.19
0.1
4.6
0.079/0.083
Mercury
mg/L
0.0018
0.000025
-
-
0.000025
Cyanide
Hg/L
1
-
270
100
400
0.001
Ammonia
(Jg/L
0.233
0.035
-
-
-
0.035
Total PCBs
^L
10
0.03
0.00017
0,000007
0.000064
0.000045
alpha BHC
Hg/L
-
-
0.00056
0.000048
0.00039
0.013
beta BHC
fg/L
-
-
0.002
0.0014
0.014
0.046
gamma BHC (lindane)
Hg/L
0.16
-
17
0.43
4.4
0.063
delta BHC
^L
-
-
-
-
-
0.34
Heptachlor
t'g/L
0.053
0.0063
0.00001
0.00000034
0.0000059
0.00021
Aldrin
UgA
0.71
0.0019
0.0000058
0.000000041
0.00000077
0.00014
Heptachlor epoxide
tig/L
-
-
0.0000074
0.0000024
0.00032
0.00011
Endosulfan 1
(Jg/L
-
-
10
7
30
0.0087
alpha Chlordane
^g/L
0.09
0.004
0.000093
0.000022
0.00032
Dieldrin
|Jg/L
0.71
0.0019
0.0000061
0.00000007
0.0000012
0.00014
4,4-DDE
^g/L
-
-
0.000051
0.00000088
0.000018
0.00059
Endrin
Hg/L
0.037
0.0023
0.035
0.002
0.03
0.0023
Endosulfan II
|1£/L
-
-
10
10
40
0.0087
4,4-DDD
|ig/L
-
-
0.000036
0.0000079
0.00012
0.00084
Endrin Aldehyde
Hg/L
-
-
0.035
-
1
0.81
Endosulfan Sulfate
Ug/L
-
-
10
-
40
2
4,4'-DDT
^/L
-
-
0.000025
0.0000012
0.00003
0.00059
Methoxychlor
Hg/L
-
-
-
-
0.02
0.03
Toxaphene
MK/L
0.21
0.0002
0.000032
-
0.00071
-
(lt From Table 11-1 of the 1996 Record of Decision
pig/L= microgram(s) per liter
ARAR = applicable or relevant and appropriate requirements
BHC = hexachlorocyclohexane
DDD = dichlorodiphenyldichloroethane
DDE = dichlorodiphenyldichloroethylene
DDT = dichlorodiphenyltrichloroethane
mg/L = milligram(s) per liter
PCB = polychlorinated biphenyl
Source: Table 2, Existing Data Review for the 2018 Five-Year Review Tulalip Landfill Site, March 2020.
C-4
-------
APPENDIX D - INTERVIEW FORMS
I I I.AI.IP I.A\I)I II I. SI PERI-I NDSI I I!
i im:-m:ar review interview iorm
Site Name: Tulalip Landfill
EPA ID: WAD980639256
Interviewer name: Rebecca C. Feldman
Subject name: Tony Reese
Subject contact information: 370-716-5056
Interview date: October 20, 2022
Interview location: Site
Interview format (identify one): In Person
Interview category: O&M Contractor
Interviewer affiliation: EPA
Subject affiliation: Big Flats
Interview time: 11:00 A.M.
Phone Mail Email Other:
1. What is your overall impression of the project, including cleanup, maintenance and reuse activities (as
appropriate)?
It is the same as it was five years ago. The cap and drainage are working. We are trying to get solar on the
Site. There are no new seeps and we have had no complaints from neighbors.
2. What is your assessment of the current performance of the remedy in place at the Site?
Same as above; everything is going well. The only thing is that we are trying to change how we test the pipes
as we do not think it is as accurate as it could be. Since the pipes are perforated, we think the dye is being
filtered out of the pipes over the distance to the cleanout.
3. What are the findings from the monitoring data? What are the key trends in contaminant levels that are being
documented over time at the Site?
Nothing has changed. Methane is staying within its respective bubble. Nothing is peaking high or low.
4. Is there a continuous on-site O&M presence? If so, please describe staff responsibilities and activities.
Alternatively, please describe staff responsibilities and the frequency of site inspections and activities if there
is not a continuous on-site O&M presence.
We are on site 40 hours a week. We test quarterly with PES. Day-to-day activities vary during the year. From
March through October, we are mowing a lot. In the off season, we test pipes when there is enough water
flowing in the pipes. We have also dealt with a lot of theft and vandalism this year. About four to five months
ago, someone painted graffiti on the container near the entrance. And a skid-steer and flatbed, as well as tools,
generator, and air compressor, were stolen. We were able to get the skid-steer and flatbed back. We have
considered security cameras, but the lack of a power source is a problem and when a camera has been put up,
the lines were cut, and it was stolen. Security is an ongoing discussion.
5. Have there been any significant changes in site O&M requirements, maintenance schedules or sampling
routines since start-up or in the last five years? If so, do they affect the protectiveness or effectiveness of the
remedy? Please describe changes and impacts.
No changes to the work that has been done. Some reporting that PES used to do, I do now.
D-l
-------
6. Have there been unexpected O&M difficulties or costs at the Site since start-up or in the last five years? If so,
please provide details.
Trespassing and vandalism are the only problems.
7. Have there been opportunities to optimize O&M activities or sampling efforts? Please describe changes and
any resulting or desired cost savings or improved efficiencies.
None. Tulalip collectively feel that there should not be any changes in site O&M activities. We feel
everything we do is a necessity and the reason why there have been no issues at the Site.
8. Do you have any comments, suggestions or recommendations regarding O&M activities and schedules at the
Site?
Nothing that hasn't already been mentioned.
9. Do you consent to have your name included along with your responses to this questionnaire in the FYR
Report?
Yes.
D-2
-------
I I I.AUI> I.ANDI II I. SI I'KRI I NDSITi:
11\ i:-yi:ar ri:\ ii:\\ interview i orm
Site Name: Tulalip Landfill
EPA ID: WAD980639256
Interviewer name:
Interviewer affiliation:
Subject name: Evan Griffiths
Subject affiliation: Jacobs
Subject contact information: 1100 112th Avenue NE, Suite 500, Bellevue, WA 98004
Interview date: October 24, 2022
Interview time: 8:00 A.M.
Interview location: home office
Interview format (identify one): In Person Phone Mail Email Other:
Interview category: O&M Contractor
1. What is your overall impression of the project, including cleanup, maintenance and reuse activities (as
appropriate)?
The Site is in good shape. Historically, there have been minor maintenance issues that have been identified
and were quickly addressed by tribal staff.
2. What is your assessment of the current performance of the remedy in place at the Site?
The remedy is working well.
3. What are the findings from the monitoring data? What are the key trends in contaminant levels that are being
documented over time at the Site?
No monitoring is currently being done.
4. Is there a continuous on-site O&M presence? If so, please describe staff responsibilities and activities.
Alternatively, please describe staff responsibilities and the frequency of site inspections and activities if there
is not a continuous on-site O&M presence.
Tribal staff are on site to maintain the cap system, which includes mowing grass, repairing access roads,
repairing storm water management systems and conducting other maintenance activities. I do not know if the
O&M presence is continuous.
5. Have there been any significant changes in site O&M requirements, maintenance schedules or sampling
routines since start-up or in the last five years? If so, do they affect the protectiveness or effectiveness of the
remedy? Please describe changes and impacts.
None that I know of.
6. Have there been unexpected O&M difficulties or costs at the Site since start-up or in the last five years? If so,
please provide details.
None that I know of.
7. Have there been opportunities to optimize O&M activities or sampling efforts? Please describe changes and
any resulting or desired cost savings or improved efficiencies.
D-3
-------
None that I know of.
8. Do you have any comments, suggestions or recommendations regarding O&M activities and schedules at the
Site?
The Site is well maintained by tribal staff, and I think they should continue to maintain it as it is currently
done.
9. Do you consent to have your name included along with your responses to this questionnaire in the FYR
Report?
Yes.
D-4
-------
APPENDIX E - DATA REVIEW FIGURES AND TABLES
Figure E-l: Landfill Gas Composition in GVS-1, GVS-2 and GVS-3
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ NN Ay A s# 4?
A^> ay -y a^ a? a*s aiv a aP ¦»'
O Cj o 0s iqs
Date
Landfill Gas in GVS-3
^ s# ^ s# ^ s# N# ^ N\^ ^ ^ ^ ^ ^ ^ ^ ^ N<1? #S $ N ^ ^ ^ 41 s? n# ^ n cr o c> Q> c> ^
Date
Source: Post-Closure Monitoring Report, Second Quarter 2022, Tulalip Landfill, Man sville. Washington. June 2022.
E-l
-------
Figure E-2: Landfill Gas Composition in GVS-4, GVS-5 and GVS-6
Source: Post-Closure Monitoring Report, Second Quarter 2022, Tulalip Landfill, Maiysville, Washington. June 2022.
E-2
-------
Figure E-3: Historical Leachate Elevations
33 t
— * - PZ-1
—¦— PZ-2
—*—PZ-3
— •- - PZ-4
—«— PZ-5
_ -I 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
CCCCC CCC C CCCCCCCCC CCCCSTC
Date
Source: Post-Closure Monitoring Report, Second Quarter 2022, Tulalip Landfill, Maiysville, Washington. June 2022.
E-3
-------
• SIM SP-11
Figure E-4: Site Infrastructure
PteErorte?
tf&Ktr kcc " hi p
A LFS rHffiW EJps lUbOjl
Q LFQwet
X Oesno/1
0 Pwew Hrt"e iS*
A Suntey nsnanerfi
O teKMe seer «crt»
3 C*ert
fecessPMd
ism-*!!;? Mtnecn sprJen items
1 I -Siew »i
A Soot end lana sJwter errs
Scuroes Eert? T«*. Juy 1P» end
SCa Erci*e:r. N:v«rOef DKC.
Figure 1. S#e infrastructure
Exissrvg Conditions
Tulalp Landfill, Msrysvrlte. Washington
JACOBS
Source: 2021 Annual Site Inspection - Tulalip (Big Flats) Landfill, Man sville. Washington. Jacobs Engineering, March 2022.
E-4
-------
Table E-l: Settlement Survey Data - Fill Area Slopes
Survey
Yraw
fill Area Slopes {%}
Northeastern Area
Central Area
Southwestern Area
Panel
A
C
S
D
Q
E
H
I
0
2000
24
2.5
2 I
2.5
2.6
2.4
2.3
2,5
2.3
2001
23
2,5
2 1
2,5
2.5
2.3
2.3
2.4
2,1
2002
2-3
2.5
2 m
2,5
2.5
2.3
2,3
2,4
2.1
2003
2 3
2.5
2.0
2,4
2,5
2.2
2.2
2.3
2,0
2004
2.3
2.5
2.0
2.5
2.5
2,2
2.2
2,3
2,0
2005
2.3
2.6
2.0
2,5
2.5
2,2
2.2
2.3
2.0
5trvry
i oar
Fill Area Slopes (%)
NortTtditLTii Area
Central Area
Southwestern Area
ICO'b
2.3
2.6
1.9
2.5
2.5
2.2
2.2
2.3
2,0
2007
2.3
2.6
2.0
2.5
2.5
2.2
2 2
2.3
2 0
2008
2.3
2.6
2.0
2.5
2,5
2,2
2,2
2,3
2,0
2009
2.3
2.8
1.9
2.5
2.5
2.2
2.2
2.3
2.0
2010
2.3
2.6
1.9
2,5
2.5
2,2
2.2
2.3
2.0
2011
2,2
2,5
1.9
2.5
24
2 1
2.1
2.3
T.0
2012
2.2
2.5
1.9
2.5
2.4
2.1
2.1
2,3
1.9
2013
2.2
2.5
1.9
2.5
2.4
2,1
2 1
2 3
1.8
2014
2 2
2.5
1.9
2.5
2.4
2.1
2.1
2.3
1.9
2015
2.2
2.5
1.9
2.5
24
2.1
2.1
2.2
1.9
2016
2.2
2.5
2.0
2.5
2.4
2.1
2.1
2.3
1.9
2017
2.2
2.5
1.8
2.5
2.4
2.1
2.1
2,3
1.9
2018
2 2
2.5
1.8
2.5
24
2.1
2.1
2,3
1.9
2013
2,2
2.5
1.8
2.5
2,4
2.1
2.1
2,3
1,9
2020
2 2
2.5
1.8
2.5
24
2.1
2.1
2.3
1.9
2021
2.2
2.5
1,8
2.5
2.4
2.1
2.1
2.3
1.9
Table E-2: Settlement Survey Data - Cut Area Slopes
Survey
Year
Cut Area Slopes <*J
Northeastern Area
Central Area
Southwestern Area
Panel
A
C
S
D
Q
E
H
1
O
2000
1,9
2,5
1,9
2,2
2.2
2,1
24
2.2
2.2
2001
1.9
2.9
1.8
2.2
2.2
2.3
2.4
2.2
2.2
2002
1 9
3.0
1.8
2.1
2.1
2.4
2,4
2.2
2.2
2003
1,0
2.6
1,9
2,1
2,1
2,2
2.2
2.1
2.1
2004
1.9
3,0
1,6
2.1
2,1
24
24
2,1
2 2
2005
1 9
3.0
1,6
2 1
2,1
24
2.1
2,2
2006
1 9
3.0
1,6
2.0
2,1
2 4
2.1
2.2
2007
1 9
3.0
1.6
2.0
2.1
22
24
2.1
2.2
E-5
-------
Yunr
Cut Area SIo[ hj i I
Northeastern Area
Central Area
Southwestern Area
tvriel
A
C
S
0
Q
E
H
)
0
2008
1.9
3.0
1.6
2.0
2.1
2.4
2.4
2.1
2,2
2009
1.9
3.0
1.5
2.0
2.1
2.4
2 4
2.0
2.1
2010
1 9
3.0
1.5
2.0
2.1
2.4
2.4
2,0
2.1
2011
1 8
2.8
1.5
2.0
2,0
2.2
2.1
2.0
2.1
2012
i e
2.8
1.5
2,0
2,0
2.2
2.1
2.0
2.1
2013
1 8
2.8
1.5
1.9
2.0
2.2
2.2
2.0
2.1
2014
1.9
2.8
1.5
1.8
2.0
2.2
2 2
2.0
2,1
2015
1J
2.8
1.5
1.9
2.0
2.2
2.1
2,0
2.1
2016
1.8
2.8
1.4
1.9
2.0
2.2
2.1
210
2.1
2017
1.8
2.8
1.4
1.9
2.0
2.2
2,2
2.0
2.1
2018
1,8
2.8
1.4
1.9
2.0
2.2
2.1
2.0
2,1
2019
1 9
2.8
1.4
1.9
2.0
2.3
2.2
2.0
2.1
2020
1 9
2.8
1,4
1.9
1.9
2.3
2.1
2.0
2.1
2021
1 9
2,8
1.4
1.9
1.9
2.3
2.2
2.0
2.1
Source: 2021 Annual Site Inspection - Tulalip (Big Flats) Landfill, Marysville, Washington, Jacobs Engineering, March
2022.
E-6
-------
APPENDIX F - SITE INSPECTION PHOTOS
Entrance gate with two remaining goats
Wetlands between the site fence and road on the east side of the Site
F-l
-------
New office trailer on the gravel pad on site
Landfill cap vegetation
F-2
-------
Piezometer PZ-2 and landfill gas monitoring location GVS-2 within fenced enclosure
Landfill cap, with equipment storage and goat/llama shelters in the background
F-3
-------
Riprap and wetland on northern side of Site, near culvert 5
; -
1 -
"" ' I) •' " i
Leaning perimeter sign along Ebey Slough
F-4
-------
Invasive blackberries growing within the riprap
F-5
-------
Last remaining llama on site
Tilted perimeter sign on Steamboat Slough
F-6
-------
mm
Invasive blackberries in riprap on the western end of the landfill
F-7
-------
Seep SP-9 area
NO
trespassing!
DO NOT
CONSUME
SHELLFISH
or fish From
THIS WETLAND
v title ll|?SC. sec 1165
ACCESS TO
CONTAtillNito-ED
AREA IS
PROHIBITED
TRIBAL ORDINANCE *49
FOR INFORMATION CONTACT:
USE PA / ®0C
TULALIP TRIBES 36
-------
Fuel tank without secondary containment, next to the equipment storage area
F-9
-------
APPENDIX G - SITE INSPECTION CHECKLIST
FIVE-YEAR REVIEW SITE INSPECTION CHECKLIST
I. SITE INFORMATION
Site Name: Tulalip Landfill
Date of Inspection: October 20, 2022
Location and Region: Marysville, Washington; 10
EPA ID: WAD980639256
Agency, Office or Company Leading the Five-Year
Weather/Temperature: 60s, cloudy and hazy from
Review: EPA Region 10
nearby forest fires
Remedy Includes: (check all that apply)
Landfill cover/containment
~ Monitored natural attenuation
Access controls
~ Groundwater containment
Institutional controls
~ Vertical barrier walls
~ Groundwater pump and treatment
~ Surface water collection and treatment
|5^I Other: natural recovery (sediment)
Attachments: EH Inspection team roster attached
PI Site map attached
II. INTERVIEWS (check all that apply)
O&M contractors completed interview questionnaires via email.
Completed forms are included in Appendix D.
1. O&M Site Manager Tonv Reese
10/20/2022
Name
Title Date
Interviewed [X] at site |~~| at office |~~| b\ phone:
Problems, suggestions |~~| Report attached: See AoDcndix D
2. O&M Staff
Name
Title Date
Interviewed P| at site P| at office P| by phone:
Problems/suggestions |~~| Report attached:
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). Fill in all that apply.
Agencv
Contact
Name Title Date Phone
Problems/sussestions PI Rcoort attached:
Agencv
Contact Name
Title Date Phone
Problems/sussestions PI Rcoort attached:
Agencv
Contact
Name Title Date Phone
Problems/suggestions |~~| Report attached:
4. Other Interviews (optional) l~~l Report attached:
G-l
-------
III. ON-SITE DOCUMENTS AND RECORDS VERIFIED (check all that apply)
1.
O&M Documents
O&M manual EH Readily available
~ Up to date
~ n/a
As-built drawings EH Readily available
~ Up to date
~ n/a
Maintenance logs ^ Readily available
Up to date
~ n/a
Remarks: EPA is in the oroccss of assessing the Site and uodatine the O&M Manual.
2.
Site-Specific Health and Safety Plan
~ Readily available
~ Up to date IE
[N/A
~ Contingency plan/emergency response plan
~ Readily available
~ Up to date IE
[N/A
Remarks:
3.
O&M and OSHA Training Records
Remarks:
~ Readily available
~ Up to date IE
[N/A
4.
Permits and Service Agreements
~ Air discharge permit
~ Readily available
~ Up to date IE
[N/A
~ Effluent discharge
~ Readily available
~ Up to date IE
[N/A
~ Waste disposal, POTW
~ Readily available
~ Up to date IE
[N/A
I"! Other Dcrmits:
~ Readily available
~ Up to date IE
[N/A
Remarks:
5.
Gas Generation Records
Readily available
Up to date EH N/A
Remarks:
6.
Settlement Monument Records
Readily available
Up to date EH N/A
Remarks:
7.
Groundwater Monitoring Records
Remarks:
~ Readily available
EH Up to date IE
[N/A
8.
Leachate Extraction Records
~ Readily available
EH Up to date IE
[N/A
Remarks:
9.
Discharge Compliance Records
~ Air EH Readily available
~ Up to date
IEIn/a
~ Water (effluent) EH Readily available
~ Up to date
IEIn/a
Remarks:
10.
Daily Access/Security Logs
Remarks:
~ Readily available
EH Up to date IE
[N/A
G-2
-------
IV. O&M COSTS
1. O&M Organization
~ State in-house ~ Contractor for state
1^1 PRP in-house Contractor for PRP
~ Federal facility in-house ~ Contractor for Federal facility
~
2. O&M Cost Records
1^1 Readily available Up to date
~ Funding mechanism/agreement in place ~ Unavailable
Original O&M cost estimate: $168.000 I I Breakdown attached
Total annual cost by year for review period if available
From:
01/01/2018
To: 12/31/2018
$297,590
1 1 Breakdown attached
Date
Date
Total cost
From:
01/01/2019
To: 12/31/2019
$237,475
1 1 Breakdown attached
Date
Date
Total cost
From:
01/01/2020
To: 12/31/2020
$263,110
1 1 Breakdown attached
Date
Date
Total cost
From:
01/01/2021
To: 12/31/2021
$233,881
1 1 Breakdown attached
Date
Date
Total cost
From:
01/01/2022
Date
To: 12/31/2022
Date
$233,881
(estimated)
Total cost
1 1 Breakdown attached
3. Unanticipated or Unusually High O&M Costs during Review Period
Describe costs and reasons: None.
V. ACCESS AND INSTITUTIONAL CONTROLS Applicable ~ N/A
A. Fencing
1. Fencing Damaged ~ Location shown on site map ^ Gates secured ~ N/A
Remarks: Fence extends along the eastern side of landfill, closest to Interstate 5. Gate at entrance is locked.
B. Other Access Restrictions
1. Signs and Other Security Measures Location shown on site map ~ N/A
Remarks: Perimeter signs along the sloughs and wetland areas.
C. Institutional Controls (ICs)
G-3
-------
1. Implementation and Enforcement
Site conditions imply ICs not properly implemented ~ Yes E No ~ N/A
Site conditions imply ICs not being fully enforced Q Yes ^ No ~ N/A
Type of monitoring (e.g., self-reporting, drive by): self-reporting by landfill manager
Frequency: On site 40 hours/week
Responsible party/agency: the Tribes
Contact
Name Title
Date
Phone
Reporting is up to date
EH Yes
~
No
IE1n/a
Reports are verified by the lead agency
~ Yes
~
No
Kl N/A
Specific requirements in deed or decision documents have been met
~ Yes
No
~ n/a
Violations have been reported
~ Yes
l£l
No
~ n/a
Other problems or suggestions: ~ Report attached
2. Adequacy ^ ICs are adequate ~ ICs are inadequate ~ N/A
Remarks: Although the 1996 Interim ROD required land use and groundwater use restrictions on all site
property as covenants running with the land to be in place. EPA believes the institutional controls currently in
place are adequate and appropriate for protecting human health and the environment.
D. General
1. Vandalism/Trespassing ~ Location shown on site map ~ No vandalism evident
Remarks: A container within the fence on the eastern edge of the Site was graffitied within the last year.
Additionally, a skid-steer and flatbed, as well as tools, generator and air compressor were stolen from the
Site. The skid-steer and flatbed were recovered.
2. Land Use Changes On Site ~ N/A
Remarks: Office trailer added to the Site but is not yet in use.
3. Land Use Changes Off Site ^ N/A
Remarks:
VI. GENERAL SITE CONDITIONS
A. Roads Applicable ~ N/A
1. Roads Damaged ~ Location shown on site map ^ Roads adequate ~ N/A
Remarks: Roads are in good conditioa although there are blackberries along the edges of the road in a few
places.
B. Other Site Conditions
Remarks:
VII. LANDFILL COVERS ^Applicable ~ N/A
A. Landfill Surface
1. Settlement (low spots) ~ Location shown on site map Settlement not evident
Area extent: Depth:
Remarks:
G-4
-------
2.
Cracks
1 1 Location shown on site map
1^1 Cracking not evident
Leneths:
Widths:
Deaths:
Remarks:
3.
Erosion
Area extent:
Remarks:
1 1 Location shown on site map
1^1 Erosion not evident
Dcoth:
4.
Holes
Area extent:
Remarks:
~ Location shown on site map
Holes not evident
Deoth:
5.
Vegetative Cover
1^1 Grass
1^1 Cover properly established
1^1 No signs of stress
1 1 Trees/shrubs (indicate size and locations on a diagram)
Remarks:
6.
Alternative Cover (e.|
Remarks:
armored rock, concrete)
~ n/a
7.
Bulges
Area extent:
Remarks:
~ Location shown on site map
Bulges not evident
Heisht:
8.
Wet Arcas/Water Damage ^ Wet areas/water damage not evident
EH Wet areas
1 1 Location shown on site map
Area extent:
1 1 Ponding
1 1 Location shown on site map
Area extent:
~ Seeps
1 1 Location shown on site map
Area extent:
1 1 Soft subgrade
1 1 Location shown on site map
Area extent:
Remarks:
9.
Slope Instability
~ Slides
~ Location shown on site map
No evidence of slope instability
Area extent:
Remarks:
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:
1 1 Location shown on site map
1 1 N/A or okay
2.
Bench Breached
Remarks:
1 1 Location shown on site map
1 1 N/A or okay
3.
Bench Overtopped
Remarks:
1 1 Location shown on site map
1 1 N/A or okay
G-5
-------
c.
Letdown Channels EH 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 (Low spots) EH Location shown on site map
EH No evidence of settlement
Area extent:
Depth:
Remarks:
2.
Material Degradation EH Location shown on site map
EH No evidence of degradation
Material tvpe:
Area extent:
Remarks:
3.
Erosion EH Location shown on site map
EH No evidence of erosion
Area extent:
Depth:
Remarks:
4.
Undercutting EH Location shown on site map
EH No evidence of undercutting
Area extent:
Depth:
Remarks:
5.
Obstructions Tvt>e:
I"! Location shown on site mat) Area extent:
Size:
Remarks:
EH No obstructions
6.
Excessive Vegetative Growth Tvoe:
~ No evidence of excessive growth
~ Vegetation in channels does not obstruct flow
I"! Location shown on site mat) Area extent:
Remarks:
D.
Cover Penetrations ^ Applicable EH N/A
1.
Gas Vents EH Active
1^1 Passive
1^1 Properly secured/locked Functioning ^ Routinely sampled EH Good condition
EH Evidence of leakage at penetration EH Needs maintenance EH N/A
Remarks:
2.
Gas Monitoring Probes
1^1 Properly secured/locked Functioning ^ Routinely sampled Good condition
EH Evidence of leakage at penetration EH Needs maintenance EH N/A
Remarks:
3.
Monitoring Wells (within surface area of landfill)
1^1 Properly secured/locked Functioning ^ Routinely sampled Good condition
EH Evidence of leakage at penetration EH Needs maintenance EH N/A
G-6
-------
Remarks: Piezometers are used to measure water/leachate levels. PZ-2 cat) was not fittins well due to
oossiblv casins or well movement, but it was still secured within the fenced area.
4.
Extraction Wells Leachate
1 1 Properly secured/locked EH Functioning EH Routinely sampled EH Good condition
EH Evidence of leakage at penetration EH Needs maintenance N/A
Remarks:
5.
Settlement Monuments EH Located Routinely surveyed EH N/A
Remarks:
E.
Gas Collection and Treatment EH Applicable ^ N/A
1.
Gas Treatment Facilities
EH Flaring EH Thermal destruction
EH Good condition EH Needs maintenance
Remarks:
EH Collection for reuse
2.
Gas Collection Wells, Manifolds and Piping
EH Good condition EH Needs maintenance
Remarks:
3.
Gas Monitoring Facilities (e.g., gas monitoring of adjacent homes or buildings)
EH Good condition EH Needs maintenance EH N/A
Remarks:
F.
Cover Drainage Layer ^ Applicable EH N/A
1.
Outlet Pipes Inspected Functioning
Remarks:
EH N/A
2.
Outlet Rock Inspected Functioning EH N/A
Remarks: Drainaee nine outlets are within the riorao on the oerimeter of the landfill.
G.
Detention/Sedimentation Ponds EH Applicable £
3 N/A
1.
Siltation Area extent: Dcoth:
EH Siltation not evident
Remarks:
EH N/A
2.
Erosion Area extent: Dcoth:
EH Erosion not evident
Remarks:
3.
Outlet Works EH Functioning
Remarks:
EH N/A
4.
Dam EH Functioning
Remarks:
EH N/A
H. Retaining Walls EH Applicable ^ N/A
1.
Deformations EH Location shown on site map
EH Deformation not evident
G-7
-------
Horizontal displacement: Vertical displacement:
Rotational displacement:
Remarks:
2.
Degradation ~ Location shown on site map
Remarks:
1 1 Degradation not evident
I. Perimeter Ditches/Off-Site Discharge ^ Applicable ~ N/A
1.
Siltation ~ Location shown on site map
1^1 Siltation not evident
Area extent:
Depth:
Remarks:
2.
Vegetative Growth ~ Location shown on site map
1^1 Vegetation does not impede flow
~ n/a
Area extent:
Type:
Remarks:
3.
Erosion ~ Location shown on site map
1^1 Erosion not evident
Area extent:
Depth:
Remarks:
4.
Discharge Structure Functioning
Remarks:
~ n/a
VIII. VERTICAL BARRIER WALLS ~ Applicable [E
N/A
IX.
GROUND WATER/SURF ACE WATER REMEDIES ~ Applicable [El N/A
X. OTHER REMEDIES
If there are remedies applied at the site and 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 designed to accomplish (e.g., to contain contaminant
plume, minimize infiltration and gas emissions).
The remedy was intended to address landfill contents and leachate that could potentially contaminate adiacent
water bodies and wetlands. Information controls (sians) are in place. The landfill is in eood condition and
well maintained. Land use on the landfill is restricted bv tribal zonine and the Consent Decree. A 2018
review of historical data and available data from studies around the Site found that sediment impacts in OU1
previously identified durine the RI do not appear to extend beyond the OU 1 wetlands and into the adiacent
sloughs.
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 activities are adcciuatc: there is a dailv orcscncc on site and anv issues are dealt with in a timelv
manner.
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 blackberries erowine alone some roads and in the riprap in some olaccs. There is also scotch
broom that srows on berms within landfill, but it is not an excessive amount and there are dla lis to remove it
manually durine the winter.
G-8
-------
D. Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy.
EPA is in the process of assessing the Site to update the O&M Manual.
Site Inspection Participants:
Rebecca C. Feldman, EPA
Dustan Bott, EPA
Dylan Houle, Big Flats
Tony Reese, Big Flats
Johnny Zimmerman-Ward, Skeo
G-9
-------
APPENDIX H - ARARS REVIEW
This FYR reviewed the chemical-specific ARARs included in site decision documents to determine if any changes
to chemical-specific standards have occurred that could affect the protectiveness of the remedy.
Table 11-1 of the 1996 interim ROD identified the federal Clean Water Act AWQC for the protection of aquatic
organisms and human health and the Washington State water quality standards for protection of aquatic life
(Washington Administrative Code Chapter 173-201A) as chemical-specific surface water ARARs for the Site.
The 1996 Interim ROD clarified that the use of AWQC to evaluate leachate seeps discharging directly into the
wetlands and tidal channels is relevant and appropriate because wetlands and tidal channels are included in the
Clean Water Act definition of surface water. A comparison of the 1996 interim ROD standards to current
standards found that 39 standards have become more stringent; all others were less stringent or did not change
(Table H-l). These results do not affect the protectiveness of the remedy as the discharge of leachate seeps to
surface water has been eliminated with construction of the final cap. If seep or surface water sampling is
conducted in the future, the most current standards should be considered in the evaluation of the data.
The 1996 interim ROD also identified the Washington State Model Toxics Control Act (MTCA) numerical
cleanup standards as relevant and appropriate to the remedial action. The MTCA regulations that pertain to the
Site are the groundwater and surface water cleanup standards contained in Washington Administrative Code 173-
340-720 and -730. The 1996 Interim ROD did not identify the specific numeric standards in effect at that time;
therefore, an evaluation of these standards for this FYR is not warranted. If groundwater and surface water
sampling is conducted in the future, the MTCA cleanup standards should be considered in the evaluation of the
data.
The 1998 ROD identifies Washington Sediment Management Standards (Washington Administrative Code 173-
204) as chemical-specific ARARs for the off-source wetlands remedial action. It notes that although these
standards are not legally enforceable on the tribal land where the Site is located, they are appropriate. The 1998
ROD did not identify the specific numerical values for the sediment standards in effect at that time; therefore, an
evaluation of the standards for this FYR is not warranted. The 1998 ROD did not require sediment monitoring and
none has been conducted. If sediment sampling is conducted in the future, detected chemical concentrations
should be compared to the current Ecology Sediment Quality Standards for marine sediments in Puget Sound.
Table H-l: OU2 Surface Water Standards Comparison
( homiciil
1«)«)(. ARAR'
(mg/l.)
2022 Siiindiird1'
(mg/l.)
( h;inge
1,1 -Dichloroethane
0.0032°
no value
less stringent
Benzene
0.071°
0.016-0.058h
more stringent
Chlorobenzene
0.129d
0.8h
less stringent
Chloroform
0.47°
2h
less stringent
Chloromethane
6.4d
no value
less stringent
Ethylbenzene
0.43°
0.130h
more stringent
Methylene chloride
1.6°
lh
more stringent
Toluene
5d
0.52h
more stringent
Trichloroethene
0.081°
0.007h
more stringent
1,2-Dichlorobenzene
1.97°
3h
less stringent
1,3 -Dichlorobenzene
1.97°
0.01h
more stringent
1,4-Dichlorobenzene
1.97°
0.9h
more stringent
2-Methylnaphthalene
0.3°
no value
less stringent
2,4-Dichlorophenol
0.79°-k
0.06h
more stringent
3,3' -Dichlorobenzidine
0.000077°
0.00015h
less stringent
Acenaphthylene
0.3°
no value
less stringent
Acenaphthene
0.71d
0.090h
more stringent
Anthracene
0.3°
0.4h
less stringent
H-l
-------
( homiciil
1«)«)(. ARAR'
(mg/l.)
2022 Siiindiird1'
(niii/l.)
( h;inge
Benzo(a)anthracene
0.00003 lc
0.0000013h
more stringent
Benzo(a)pyrene
0.00003 lc
0.00000013h
more stringent
Benzo(b)fluoranthene
0.00003 lc
0.0000013h
more stringent
Benzo(g,h,i)perylene
0.3e
no value
less stringent
Benzo(k)fluoranthene
0.00003 lc
0.000013h
more stringent
Bis(2-chloroethyl)ether
0.0014°
0.0022h
less stringent
Bis(2-ethylhexyl)phthalate
0.0059°
0.00037h
more stringent
Chrysene
0.000031°
0.00013h
more stringent
Di-n-butylphthalate
12°
0.030h
more stringent
Dibenz(a,h)anthracene
0.000031°
0.00000013h
more stringent
Diethylphthalate
120°
0.600h
more stringent
Fluoranthene
0.016d
0.020h
less stringent
Fluorene
0.3°
0.070h
more stringent
n-Nitrosodiphenylamine
0.016°
0.006h
more stringent
Naphthalene
2.35°
no value
less stringent
Pentachlorophenol
0.0079f
0.00004h
more stringent
Phenanthrene
0.0046d
no value
less stringent
Phenol
5.8°
300h
less stringent
Pyrene
0.3°
0.030h
more stringent
4,4-Dichlorodiphenyldichloroethane
0.00000084°
0.00000012h
more stringent
4,4-Dichlorodiphenyldichloroethylene
0.00000059°
0.000000018h
more stringent
4,4-Dichlorodiphenyltrichloroethane
0.00000059°
0.00000003h
more stringent
Aldrin
0.00000014°
0.00000000077h
more stringent
Alpha-Hexachlorocyclohexane
0.000013°
0.00000039h
more stringent
Arochlor-1016
0.000000045°
0.000000064hl
less stringent
Arochlor-1232
0.000000045°
0.000000064hl
less stringent
Arochlor-1242
0.000000045°
0.000000064hl
less stringent
Arochlor-1248
0.000000045°
0.000000064hl
less stringent
Arochlor-1254
0.000000045°
0.000000064hl
less stringent
Arochlor-1260
0.000000045°
0.000000064hl
less stringent
Beta-Hexachlorocyclohexane
0.000046°
0.000014h
more stringent
Chlordane
0.00000059°
0.00000032h
more stringent
Delta-Hexachlorocyclohexane
0.00034°
no value
less stringent
Dieldrin
0.00000014°
0.0000000012h
more stringent
Endosulfan I
0.0000087f
0.00000871
no change
Endosulfan II
0.0000087f
0.00000871
no change
Endosulfan Sulfate
0.002°
0.04011
less stringent
Endrin
0.0000023f
0.00000231
no change
Endrin aldehyde
0.00081°
0.001h
less stringent
Gamma- Hexachlorocyclohexane
(Lindane)
0.000063°
0.000161 acute
less stringent
Heptachlor
0.00000021°
0.0000000059h
more stringent
Heptachlor epoxide
0.00000011°
0.000000032h
more stringent
Methoxychlor
0.00003d
0.00002h
more stringent
Antimony
0.5d
0.64h
less stringent
Arsenic
0.00014°
0.00014h
no change
Cadmium
0.0093f
0.00791
more stringent
Chromium (VI)
0.05f
0.0501
no change
Copper
0.0024/0.0029d/g
0.00311
less stringent
Cyanide
O.OOls
o.oor
no change
Lead
0.0056/0.0085d
0.00811
more stringent
Mercury
0.000025d
0.000941
less stringent
Nickel
0.0079/0.0083d
0.00821
more stringent
Selenium
0.071f
0.0711
no change
H-2
-------
( homiciil
I«)«)(. ARAR'
img/l.)
2022 Siiindiird1'
(mg/l.)
( h;inge
Silver
0.0023s
0.00191
more stringent
Thallium
0.0065°
0.00047
more stringent
Zinc
0.076/0.086'
0.0811
more stringent
Ammonia
0.035'
0.0351
no change
Notes:
a)From Table 11-1 of the 1996 Interim ROD.
b) Federal AWQC obtained from https://www.epa.gov/wac/national-recommended-water-qualitv-criteria-aauatic-life-criteria-table and
https://www.epa.gov/wac/national-recommended-water-qualitv-criteria-human-health-criteria-table (accessed 10/20/22). The lowest
value from the aquatic life criteria table (saltwater acute/saltwater chronic) and the human health criteria table (human health for the
consumption of organism only) is presented in the table. In the absence of an AWQC, the values presented are the 2019 state water
quality standards (aquatic life criteria, marine water acute/chronic) available at
https://fortress.wa. gov/ecv/publications/documents/0610091 .pdf (accessed 10/20/22).
c) Human health federal fish consumption water quality criteria (40 CFR Part 131).
d) Eco = marine AWQC chronic (40 CFR Part 131).
e) Eco = marine AWQC acute (40 CFR Part 131).
f) Eco = Washington state marine chronic (WAC 173-201A).
g) Eco = Washington state marine acute (WAC 173-201A).
h) Federal AWQC, human health for the consumption of organism only.
i) Federal AWQC, aquatic life criteria, saltwater acute/chronic.
j) State surface water quality standard (aquatic life criteria, marine water acute/chronic).
k) The 2013 FYR Report noted that the ARAR for 2,4-dichlorophenol has always been 0.79. The 1998 ROD included a typographical
error and mistakenly listed 0.97 as the value for this compound.
1) Value applies to total polychlorinated biphenyls (PCBs) (e.g., the sum of all congener or all isomer or homolog or Aroclor analyses).
mg/L = milligrams per liter
H-3
------- |