I
Fifth Five-Year Review
Report
Western Processing Superfund Site
Kent, Washington
September 2013
PREPARED BY
U.S. Environmental Protection Agency
Region 10
Seattle, Washington
Approved by:
w-. jQ.
Cami Grandinetti
Date:
'l/zi j(3
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Table of Contents
List of Figures
List of Tables iv
Executive Summary
List of Abbreviations ix
1. Introduction
2. Site Chronology 11
3. Background 12
3.1. Site Location and Description 12
3.2. Site History 13
3.2.1 Early Investigations 13
3.2.2 Early Actions 13
3.2.3 Surface Cleanup 14
3.2.4 Remedial Planning Activities 14
4. Remedial Actions 15
4.1. Record-of-Deci si on (ROD) 15
4.2. ROD Clean up Goal 17
4.2.1. Cleanup Goals/Standards 17
4.2.2. Performance Goals 17
4.2.3. Consent Decree 18
4.3. Remedy Implementation 18
4.3.1. Subsurface Cleanup 18
4.3.2. Groundwater Cleanup 18
4.3.3. Mill Creek 19
4.3.4 EastDrain 20
4.4. Explanation of Significant Differences (ESD) 20
4.4.1 Post ESD Status 21
5. Progress Since Last Review Last
5.1 Protectiveness Statement from the Fourth Five-Year Review 24
5.2 Status of the Recommendations and Follow-up Actions from Fourth Five-Year Review ....24
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6. Five-Year Review Process 25
6.1. Notification of potentially interested parties 26
6.2. Review of site-related documents 26
6.3. Site visit, inspection and interviews 26
6.4. Site Conditions and progress 27
6.5. Data Review 27
7. Technical Assessment 28
7.1. Question A: 28
7.2. QuestionB: 28
7.3. Question C: 29
7.4. Technical Assessment Summary 29
8. Issues 31
9. Recommendations and Follow-Up Actions 31
10. Statement of Protectiveness 32
11. Next Review 32
Appendices: 33
Appendices: List of Documents Reviewed 34
Site Inspection Check List 39
Site Photographs 48
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List of Figures
Figure 1-1. Western Processing Vicinity Map 30
Figure 1-2. Western Processing Site Plan 31
Figure 1-3. Western Processing Groundwater and Surface Water Quality Monitoring Locations -
2011 32
Figure 1-4. Containment Extraction System 33
List of Tables
Table 1. Chronology of Site Events 8
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Executive Summary
The remedy for this site was originally selected prior to passage of the Superfund Amendments
and Reauthorization Act (pre-SARA) and the remedy does not allow for unlimited use and
unrestricted exposure, and thus this is a policy Five-Year Review.
EPA and Washington State Department of Ecology (WDOE), referred to as the Governments in
Site-related documents, continue to conduct joint oversight of the Site with EPA maintaining
responsibility for conducting Five-Year Reviews. Meetings are held on-site biannually to
conduct field inspections and data/document reviews.
All data indicate that the remedy has been operating successfully for many years. Pumping and
treatment rates have been dramatically decreased over time and continue to be effective in
containing contamination within the confining slurry wall and RCRA cap constructed onsite.
The monitored natural attenuation remedy applied in the off-site trans plume areas has been
shown to be effective in reducing the size and contaminant concentrations of the groundwater
plume. Monitoring data indicate that the trans plume has biodegraded to levels well below the
ROD action levels. The site file includes a record of the documentation of Site remedial
activities and performance and is summarized later within this document.
The remedy for the Western Processing site currently protects human health and the environment
because the contaminated groundwater and soil within the source area are contained by the slurry
wall, the RCRA cap, and the inward gradient containment pumping and associated treatment
system. The trans plume groundwater contaminant concentrations outside the slurry wall have
attenuated to below detection levels. However, for the remedy to be protective in the long term,
institutional controls that run with the land need to be placed on the contaminated properties.
A comparison of 1996 post remedy implementation East Drain sediment monitoring results for
PAHs to the Washington Department of Ecology Freshwater Sediment Quality Standards
(became effective September 2013) calls into question the protectiveness of the remedy for
benthic biota in the East Drain. Additional sampling and evaluation of sediments in the East
Drain and Mill Creek is recommended to determine if protectiveness is still being maintained for
site sediments.
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Five-Year Review Summary
SITE IDENTIFICATION
Site Name: Western Processing
EPA ID: WAD0009487513
Region: 10
State: WA
City/County: Kent, King
SITE STATUS
NPL Status: Final
Multiple OUs?
Yes
Has the site achieved construction completion?
Yes
Lead agency: US EPA Region 10
Author name (Federal or State Project Manager): Joe Wallace
Author affiliation: USEPA
Review period: July 2008 - July 2013
Date of site inspection: 02/06/2013
Type of review: Policy
Review number: 5
Triggering action date: 07/24/2008
Due date (fiveyears after triggering action date): 07/24/2013
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Five-Year Review Summary Form (continued)
Issues/Recommendations
C) 1 (s) without Issues/Recommendations Identified in the I'ive-Year Ueview:
OU #1 and OU #3. Removal actions were completed for OU #1 and #3 and no
issues remain. Monitoring of these areas is addressed in O&M of OU#2.
Issues and Uecommcndalions Identified in the hive-Year Ueview:
OU(s): 02
Issue Category: Institutional Controls
Issue: Permanent Institutional Controls need to be developed and
implemented that run with the land for those parcels which constitute
Sector 1 (within the boundaries of the slurrv walH
Recommendation: Develop and implement Institutional Controls
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight
Party
Milestone Date
No
Yes
EPA
EPA
09/30/18
OU 2
Issue Category: Remedy Performance
Issue: Concentrations of PAHs in the East Drain are elevated considerably
above the State of Washington's new Freshwater Sediment Standards
calling into question the protectiveness of the sediment portion of the
remedy.
Recommendation: Evaluate PAH concentrations in Mill Creek and East
Drain and determine whether contamination found is related to the site.
Determine whether the sediment remedy is protective.
Affect Current
Protectiveness
Affect Future
Protectiveness
Implementing
Party
Oversight Party
Milestone Date
Deferred
Deferred
Trust
EPA/WDOE
9/30/15
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Sitewide Protectiveness Statement (if applicable)
Protectiveness Determination: Addendum Due Date (if applicable):
9/30/15
Protectiveness Deferred
Protectiveness Statement:
Based on this Technical Assessment, a protectiveness determination related to the remedy for the
Western Processing Site cannot be made at this time. Additional data needs to be collected for the
sediment portions of the remedy (East Drain and Mill Creek) to ensure they remain protective. With the
exception of these sediment areas, the remedy currently protects human health and the environment in the
short term because the contaminated groundwater and soil in the source area are contained within the
slurry wall, the RCRA cap and the containment pumping and treatment system. The groundwater
concentrations off the Western Processing property have decreased to below detection levels. There are no
current exposures to site contaminants related to these portions of the remedy. However, for the remedy to
be protective in the long term, institutional controls that will run with the land need to be placed on the
properties located within the area bounded by the slurry wall.
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List of Abbreviations
ARAR Applicable or Relevant and Appropriate Requirement
AWQC Federal Ambient Water Quality Criteria
bgs below ground surface
CD Consent Decree
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
DCE 1,2-dichloroethane
CFR Code of Federal Regulations
EPA United States Environmental Protection Agency
ESD Explanation of Significant Difference
gpm gallons per minute
NCP National Contingency Plan
NPL National Priorities List
O&M Operation and Maintenance
PAH Polycyclic aromatic hydrocarbons
PCB Polychlorinated Biphenyl
POTW Publicly Owned Treatment Works
PRP Potentially Responsible Party
RA Remedial Action
RAO Remedial Action Objective
RCRA Resource Conservation and Recovery Act
RD Remedial Design
RI/FS Remedial Investigation/Feasibility Study
ROD Record of Decision
RPM Remedial Project Manager
SARA Superfund Amendments and Reauthorization Act 1986
SQS Washington State Freshwater Sediment Standards
TCE trichloroethylene
VOC Volatile Organic Compound
WDOE Washington Department of Ecology
WP Western Processing
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1. INTRODUCTION
The purpose of a Five-Year Review is to determine whether the remedy at a Superfund site is
protective of human health and the environment. The methods, findings, and conclusions of
reviews are documented in Five-Year Review reports. In addition, Five- Year Review reports
identify issues found during the review, if any, and identify recommendations to address them.
Remedial work began at Western Processing Site before the passage of the Superfund
Amendments and Reauthorization Act of 1986 (SARA), therefore, this Five-Year Review is a
policy review rather than a statutory review. The U.S. Environmental Protection Agency
(EPA) Region 10 is preparing this Five-Year Review report consistent with CERCLA ง121
and the National Contingency Plan (NCP). CERCLA ง121 states:
If the President selects a remedial action that results in any hazardous substances,
pollutants, or contaminants remaining at the site, the President shall review such
remedial action no less often than each five years after the initiation of such remedial
action to assure that human health and the environment are being protected by the
remedial action being implemented. In addition, if upon such review it is the judgment
of the President that action is appropriate at such site in accordance with section [104]
or [106, the President shall take or require such action. The President shall report to
the Congress a list offacilities for which such review is required, the results of all such
reviews, and any actions taken as a result of such reviews.
The Agency interpreted this requirement further in the NCP; 40 CFR ง 300.430(f)(4)(ii) which
states:
If a remedial action is selected that results in hazardous substances, pollutants, or
contaminants remaining at the site above levels that allow for unlimited use
and unrestricted exposure, the lead agency shall review such action no less often than
every five years after the initiation of the selected remedial action.
This is the fifth Five-Year Review for the Western Processing Site located in Kent,
Washington. The triggering action for this review is the completion of the Fourth Five-Year
Review Report, dated July 24, 2008. This Fifth Five-Year Review was conducted by EPA
Region 10's Remedial Project Manager (RPM) for the period from July 2008 through July
2013. This Five-Year Review has been conducted because hazardous substances,
pollutants, or contaminants remain in the soil and groundwater above levels that allow for
unlimited use and unrestricted exposure. This report documents the results of the review.
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2. SITE CHRONOLOGY *
Table 1. Chronology of Site Events
Event
Date
Western Processing begins Site operations
1961
Site closed by court order
July 1983
Emergency removal of site wastes
July 1983
Site placed on NPL
September 1983
1st Consent Decree entered by the Court
August 1984
Surface Clean up ROD issued (Phase I)
August 1984
Surface Cleanup
November 1984
Record of Decision issued (Phase II)
September 1985
Amended Record of Decision issued
September 1986
Consent Decree entered by the Court
April 1987
Subsurface remediation begun
August 1987
Operations for both P&T systems begun
October 1988
Slurry wall constructed around the site
October 1988
Preliminary Close Out Report
December 1991
Three-Year performance standards achieved for Mill Creek
August 1993
Mill Creek restoration
September 1993
First Five-Year Review
January 1993
East Drain extraction system installed
November 1994
ESD issued
December 1995
Containment wells installed
June 1996
New treatment system started
July 1997
Final on-site subsurface waste removal
October 1997
Second Five-Year Review
September 1998
RCRA Cap completed
October 1999
Start of Trans Plume MNA
April 2000
Third Five-Year Review
September 2003
Fourth Five-Year Review
July 2008
Installation of low flow stripping tower and extraction pump size
reduction
January 2009
Approval of Long Term Contingency Plan Addendum
January 2009
72ncl Avenue Extension - Well Decommissioning
December 2012
* Note: The Site File contains contradictory information on some of the dates in this table. Therefore
dates should be considered approximate.
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3. BACKGROUND
3.1. Site Location and Description
The Superfund Site was placed on the National Priorities list (NPL [Superfund list]) in
September 1983.
The Western Processing Company, Inc. operated from 1961 to 1983 on a 14 acre parcel of land
approximately two miles north of the city center of Kent, Washington in the Kent Green River
Valley (See Figure 1-1). The area was a former farming region and over time has developed
into a light industrial/commercial area. The area just to the north of the Site is undeveloped.
East of the Site lies the Interurban Trail used by walkers and bicyclists and runs parallel to a rail
line and a railroad drainage ditch (East Drain). The area south of the Site has been developed
for light industry. Mill Creek lies just outside of the eastern boundary of Sector 1, the
containment cell, and flows in a northerly direction into the Black River, a tributary of the
Green River. The Green River flows into the Duwamish River before ultimately emptying into
Puget Sound at Seattle. The trans plume area, Sectors 2 and 3, extends from the slurry wall,
then under Mill Creek to the east for approximately 800 feet beneath several light industrial
warehouses. The Site is located above the 100-year flood plain over an alluvial shallow aquifer,
with the groundwater table at 5 to 10 feet below ground surface (bgs). There are no wells
currently used for drinking water in the shallow aquifer within a one-mile radius of the site.
Background water quality of the shallow aquifer does not meet current drinking water
standards, primarily for inorganic compounds. The city of Kent (pop. 71,610), of which the
Site is a part, obtains its drinking water from a much deeper, hydraulically isolated aquifer
more than a mile southeast (hydraulically up gradient) of the Site.
Three major geologic units comprise the hydrogeologic system in the vicinity of the Site. These
units comprise the White River Alluvium, the valley fill deposits that occur throughout the Kent
Valley and beneath the Site. Alluvial fill consists primarily of sand, silt, and clay with occasional
layers of sandy gravel. White River Alluvium is not considered to be a major drinking water
source due to naturally occurring poor water quality. Groundwater is encountered at 5 to 10 feet
bgs. Shallow groundwater (Zone A [shallow aquifer in a complex sequence of discontinuous
interbedded silt, sand, and clay lenses to a depth of 40 feet bgs]) flows northwest from the Site
and discharges into Mill Creek. The deeper aquifer (Zone B [a fairly continuous fine to medium
sand with intermittent silty zones]) begins at 40 feet bgs and extends to a depth of 80 feet bgs.
Groundwater in this unit flows northwest also, but generally passes below Mill Creek.
Contaminants found in Zone A at the Site migrated into Mill Creek prior to the installation of the
Sector 1 slurry wall, and the contaminants in Zone B were transported beneath Mill Creek and
downgradient of the Site into Sectors 2 and 3, the trans plume area. A third groundwater zone,
Zone C, extends from about 80 to 120 feet bgs but has not been impacted by Site contamination.
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Originally, Western Processing was a processor of animal by-products and brewer's yeast.
Subsequently, the business expanded to recycle, reclaim, treat, and dispose/bury/store many
different types of industrial wastes. Over 300 businesses, including some of the Pacific
Northwest's largest industries, had contracts with Western Processing to handle their wastes.
Processes at the Site included the recovery of metals from sludges and liquid wastes, spent solvent
recovery, reclamation of caustics, flue ash, and ferrous sulfide, reprocessing pickle liquor,
electrolytic destruction of cyanides, chemical recombination to produce zinc chloride and lead
chromate, and waste oil reclamation. Operations ceased in 1983 by order of the EPA.
3.2 Site History:
3.2.1 Early Investigations
Local agencies became concerned with operations at the Western Processing in the
1970s and early 1980s. EPA inspected the facility in March 1981 to determine compliance
with the then new Resource Conservation and Recovery Act (RCRA) regulations. In August
1982, EPA issued a RCRA 3013 order requiring Site owners/operators to investigate
contamination in soil, surface water, and groundwater. After failure of the owners/operators
to comply, EPA undertook the investigation in September 1982. Of the approximately 5,000
drums stored on site, many were leaking, corroded, or bulging. In several locations, drums
containing incompatible materials (e.g. cyanides and ketones, acids and caustics, acids and
ethyl amines) were stored together. During the sampling, battery casings were found at depths
of 15' to 24' bgs.
Analysis of soil and groundwater samples confirmed that hazardous substances had been
released into the environment, had contaminated the shallow aquifer, and had caused
widespread contamination of soils at the Site. Primary contaminant groups included:
Halogenated volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs),
phenolic compounds, and metals.
Concurrent with the investigations by EPA, Washington State's Department of Ecology
(WDOE) conducted its own investigation of the Site under the authority of the laws of
Washington State.
3.2.2 Early Actions
In April 1983, EPA issued a CERCLA Section 106 order requiring the owners/operators to cease
operations immediately and to provide assurances that they would conduct a cleanup. When
these assurances were not obtained, EPA used Superfund money to conduct an immediate
removal operation to stabilize the Site. Work began in late April 1983 and was completed in
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July 1983. Over 1,900 cubic yards of solids/sludges and 930,000 gallons of waste liquids and
hazardous substances were removed from the Site. The Western Processing facility was
permanently closed by court order in July 1983 and was listed on EPA's National Priorities List
in September 1983.
Using state funds, the Washington Department of Ecology (Ecology) implemented storm water
control measures at the Site in the fall of 1983.
3.2.3 Surface Cleanup
A Focused Feasibility Study for Surface Cleanup was published in June 1984 and was followed by
a Record of Decision in August 1984. Under a August 1984 Consent Decree, a group of over 190
Potentially Responsible Parties (PRPs), currently referred to as the Western Processing Trust Fund
(Trust), undertook the surface cleanup at a cost of over $10 million designated as Phase I of the
remediation. Over 2,400 truckloads of chemical waste and contaminated soil and debris were
removed from the Site. Once all surface structures (buildings, tanks, impoundments, and waste
piles) were cleared from the Site, the Site was graded to prevent storm water runoff, a lined pond
was constructed to contain the collected storm water, and a portable treatment plant was brought
on site to treat the collected water.
The Phase 1 surface cleanup was completed in November 1984, with the exception of a storage
tank containing a dioxin-contaminated oily liquid. This liquid was drummed and placed in
plastic-lined trailers on the Site. Numerous attempts were made to arrange for disposal of this
material, primarily through incineration at off-site locations. However, public and news-media
reaction opposed this method of disposal. Ultimately, in 1986, the Trust had the dioxin-
containing materials destroyed by successfully treating approximately 6,000 gallons of the
liquid on site with the KPEG (potassium hydroxide, polyethylene glycol) mobile chemical
dechlorination process. Residual material from the treatment process was shipped to Chemical
Waste Management's SCA incinerator in Chicago. No other dioxin contamination was found on
site.
3.2.4 Remedial Planning Activities
EPA's phased Remedial Investigation/Feasibility Study (RI/FS) work, which began during the
summer of 1983 and proceeded simultaneously with the surface cleanup, added to the information
obtained from the study undertaken under the RCRA 3013 order. Over 90 of EPA's 126 priority
pollutants were found in soil, groundwater, and surface water, with heavy metals, polychlorinated
biphenyls (PCBs), phenols, and volatile organic compounds (VOCs) being the predominant
contaminants. Over 95% of the contamination was determined to be contained within the
uppermost fifteen feet of soil. Groundwater contamination for the most part was concentrated
from the water table to approximately 30 feet bgs (i.e., within Zone A). Extremely high
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concentrations of contaminants were found in this shallow groundwater with maximum detected
concentrations of up to 510,000 milligrams/liter (mg/1; parts per million [ppb]) of zinc, up to 5,400
ppm of total semivolatile organic compounds, and up to 1,346 ppm of total volatile organic
compounds (VOCs).
In March 1985, a complete RI/FS was released to the public. A series of four public
meetings/workshops were held at Kent City Hall. Those alternatives involving excavation and off-
site disposal combined with a groundwater pump and treat system were most favored.
An intensive soil and subsurface waste sampling program was conducted by the Trust 1986 to
obtain pre-design information for excavation of the most highly contaminated subsurface wastes.
During that test investigation, concentrations of metals in soils were detected at up to
approximately 141,000 milligrams/kilogram (mg/kg; parts per million [ppm]) of lead;
10,000 ppm of PCBs; 53,000 ppm of total polycyclic aromatic hydrocarbons (PAHs); and 580
ppm of individual (e.g., trichloroethene) VOCs. Contamination had not been detected beyond a
depth of about 70 feet bgs. Off-property surface soils analysis indicated the presence of metals
and organic compounds, which may have been transported off the property by wind.
Site shallow groundwater (Zone A) flows to the northwest into Mill Creek. The RI/FS had
previously indicated that groundwater was captured to a depth of approximately 50 to 60 feet below
grade by Mill Creek, and therefore, Mill Creek acted as a hydraulic barrier for the flow of shallow
contaminated and even the deeper, less contaminated groundwater. Because of the concept that
Mill Creek acted as a hydraulic barrier to the flow of site groundwater, contaminated groundwater
was not believed to migrate beyond the creek.
However, the installation of additional monitoring wells west of and hydraulically down gradient of
Mill Creek led to a Supplementary Remedial Investigation report in July 1986. The report revealed
that a plume identified at that time as trans-1,2-dichloroethene (trans plume) had migrated under
Mill Creek and was detected in wells in groundwater Zone B 40 to 70 feet bgs, and as far as 800
feet west of Mill Creek.
4. REMEDIAL ACTIONS
4.1. Record-of-Decision (ROD)
Following the August 1984 Surface Cleanup ROD (Phase I ROD), the EPA Regional
Administrator approved a ROD (Phase II ROD) in September 1985 requiring the following
Remedial Action Objectives:
Prevent direct human contact with or ingestion of contaminated soils either on or off-site;
Prevent the further spread of and, if possible, removal of the contamination from the
shallow aquifer
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Prevent further contaminant discharges (via groundwater) to Mill Creek at levels which
are harmful to aquatic organisms
Control contaminated storm water runoff from the site
Major cleanup elements were:
Conduct an extensive soil and subsurface waste sampling program, both on- and off-site
property;
Excavation and off-site disposal of the most highly contaminated soils and non-soil
material;
Elimination of direct contact threats in nearby off-property areas by excavation of all
soils exceeding the acceptable daily intake (ADI) level or the 1 X 10"5 (1 inl00,000)
excess cancer risk level and by covering remaining soils having above background
concentrations of priority pollutants;
Construction and operation of a shallow groundwater extraction system for a
minimum of 5 to 7 years,
Construction, operation, and maintenance of a groundwater treatment plant;
Construction, operation, and maintenance of a storm water control system;
Excavation of contaminated East Drain sediments which may have been affected by
Western Processing;
Attainment of the Mill Creek performance standard, identified as the ambient water quality
criteria for aquatic organisms or the upstream background, and excavation of contaminated
Mill Creek sediments;
Continued monitoring of Mill Creek, the East Drain, groundwater, and
the groundwater extraction/treatment system performance;
Construction and maintenance of a RCRA consistent cap over the source area
after pumping is completed;
Long-term surface water and groundwater monitoring;
Perform conditionally required actions if the performance standards are not achieved or if
it appears that more than 20 years of groundwater extraction will be necessary; and
Apply institutional controls, such as deed restrictions, as needed.
An amended ROD was signed on September 4, 1986. It required remediation (construction and
operation of a groundwater extraction and treatment system) of the trans plume, which had
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migrated off the facility site and was detected west of Mill Creek during the Supplemental
Remedial Investigation. Although the trans plume was originally identified as trans-1,2-
dichloroethene it consisted primarily a chemically similar compound, cis-1,2 dichloroethene.
4.2. Amended ROD Clean Up Goals
4.2.1. Cleanup Goals/Standards
The following cleanup goals were established in the September 1986 amended ROD:
Surface water quality goals for Mill Creek (adjacent to site) are the Federal Ambient Water
Quality Criteria (AWQC) or background-derived concentrations where upstream
concentrations approach or exceed the AWQC. These goals were applied at designated
downstream sampling points. The Consent Decree required that these goals be met within
three years.
Prior to remediation, shallow contaminated groundwater from the Site discharged to Mill
Creek. The goal of achieving compliance with the AWQC in Mill Creek was also
considered to be a means of assessing the effectiveness of the remedy for the shallow
groundwater flowing from the Site. There were no other on-site cleanup goals set for the
shallow groundwater. The performance standards established in the amended ROD
required a cleanup level 70 ug/1 for cis-1, 2-dichloroethene in the trans plume.
4.2.2. Performance Goals
The following treatment performance goals were established in the amended ROD:
Achievement of an inward flow of shallow groundwater (<40 ft bgs) within the area
approximately defined by the Site's property boundaries. This could be accomplished by
either:
1) a reversal of groundwater flow for Zone B at a depth of 40 to 70 feet at the western
boundary of the site: or
2) establishment of a hydraulic barrier to regional groundwater flow at the 40-to
70-foot depth at the western boundary of the site.
All air emissions were required to comply with a discharge permit issued from the Puget
Sound Air Pollution Control Agency.
The collected treated wastewater effluent from the treatment systems was required to
meet discharge criteria specified in the POTW (publicly owned treatment works)
discharge permit.
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4.2.3. Consent Decree
After the September 1985 signing of the Phase II ROD, EPA entered into extensive negotiations
with the PRPs during which EPA began conducting a Fund-lead cleanup. However, in 1986
individual PRPs, precursors to the Trust, signed the Phase II Consent Decree for the subsurface
cleanup described in the Phase II ROD (1985) and amended ROD (1986). Following a public
comment period, a consent decree was entered by the court in April 1987.
4.3. Remedy Implementation
4.3.1. Subsurface Cleanup
In the fall of 1986, the Trust conducted the soil and soil/waste sampling program and
geophysical investigation. An on-site lab was utilized to facilitate sample analysis turnaround
times. Over 1,500 soil and waste samples were collected and analyzed over a four month
period. This data was used to determine the limits of excavation of on-site subsurface wastes
and off-property contaminated soils.
In January 1987, the Trust conducted the Phase II subsurface cleanup at an estimated cost of $40
million. The Trust submitted work plans for the remedial action, which were approved by EPA
and WDOE.
Subsurface cleanup began on an aggressive schedule during which design and construction
proceeded simultaneously. In the summer of 1987, construction activities began which included:
excavating and Class 1 RCRA landfill disposal of over 25,000 cubic yards of highly contaminated
soil and sludge, installing two groundwater extraction and treatment systems, and design of a
slurry wall to enclose the Site. Groundwater extraction and treatment began in October 1988.
4.3.2. Groundwater Cleanup
Fifty four new monitoring wells were installed in late 1987 and early 1988 to be used in the long-
term groundwater monitoring program. Implementation of the monitoring program, including Mill
Creek and East Drain surface water monitoring, began in January 1988. The PRPs chose to
construct an on-site lab, compliant with EPA's Contract Laboratory Program (CLP) dedicated to
analyzing Western Processing samples. Construction of the lab was completed in January 1988.
Peak load for the lab was expected to be over 9,000 sample analyses per year but was later
increased to more than 11,000 samples per year.
Construction of the Sectors 1, 2 and 4 shallow groundwater extraction and infiltration system and
the Sector 3 trans plume extraction system began in January 1988 and was completed in May
1988. In addition, seven "barrier" monitoring wells were installed west of Mill Creek.
The original groundwater treatment plant was completed in July 1988. It was designed with two
major components: air stripping for VOCs, followed by treatment for metals and semi volatile
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organic compounds. Air stripper operations began in August 1988, with thermally regenerated
carbon adsorption units to capture vapor-phase contaminants. After processing by the two
treatment systems, extracted groundwater was discharged to METRO (currently the KCIW [King
County Industrial Waste Program]), the local POTW, or reinjected into the ground through the
infiltration system.
The original treatment system for groundwater collected from the original well-point
extraction system included stripping of VOCs, followed by oxidation of phenolic compounds
with hydrogen peroxide, reduction of hexavalent chromium to the trivalent form, pH
adjustment, metals precipitation, and carbon polishing.
Because of severe fouling of the on-site stripping tower by inorganic precipitates, the treatment
sequence was modified in September 1989 to provide metals precipitation before stripping of VOCs.
After 1989, phenol oxidation and hexavalent chromium reduction were discontinued. Liquid-phase
activated carbon filters were used to remove contaminants from treated water before discharge to the
POTW.
The final major element of the cleanup, a field modification that supplemented the remedial
action described in the ROD and the Amended ROD, was the installation of a 40 feet deep,
4,400 foot long slurry wall (see Figure 1-3 for alignment). The wall, which now surrounds
Sectors 1 and 4, was completed in October 1988. The slurry wall serves to contain
contaminated Site soil and groundwater and greatly increases efficiency of the extraction well
pumping effort.
The Trans Plume extraction system consists of three wells (T wells) in Sector 3, and 2 wells (U
wells) in Sector 2 screened between 40 and 70 feet bgs. The Consent Decree required overlapping
zones of influence for these extraction wells. A capture zone analysis confirmed that the trans
plume extraction wells effectively captured the plume and were adequately containing the
contamination found in the Zone B groundwater. Water extracted from the T and U wells was
directed to a separate treatment system consisting of a sand filter bed and an air stripper. Effluent
from this system was re-inj ected into the Site infiltration gallery within the slurry walls or discharged to
the POTW.
Contaminant concentrations in groundwater and water levels are measured using a system of 51
monitoring wells and 28 piezometers located on and off site in Zone A and Zone B.
4.3.3. Mill Creek
The Phase II ROD, amended ROD, and Consent Decree required that Mill Creek sediments be
tested to determine if leachable and/or bioavailable contaminants, which may have originated at
the Site, were present and could adversely impact aquatic organisms. This investigation was
completed in 1992. Specific reaches of Mill Creek were identified for remediation.
Remediation consisted of removal of contaminated creek bottom sediment with an auger head
dredge and cover of the east creek bank soil with clean material after removing the surficial soil
layer. Creek bed sediments were sampled after dredging was completed in 1993 and found to
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contain metal contaminants above acceptable levels. Additional remedial action was taken to
isolate contaminants under a minimum 4-inch gravel bed placed in the creek. Gravel placement
was completed in 1994.
4.3.4. East Drain
The Phase II ROD, amended ROD and Consent Decree required that East Drain sediments be tested
to determine if leachable and/or bioavailable contaminants which may have originated at the Site
were present and could adversely impact aquatic organisms. Investigation results indicated that
certain areas of the East Drain contained metals exceeding cleanup levels. Metal contaminants were
also found in the relatively stagnant shallow groundwater zone between the East Drain and slurry
wall during the investigation completed in 1992.
Remediation of East Drain sediments was undertaken in 1993 and included removal of
sediments with a track excavator and front-end tire loader. Over 1,140 tons of sediment
were shipped to the Waste Management Columbia Ridge Landfill, near Arlington, Oregon.
Class A gravel borrow was used as backfill material in excavated areas.
Remedial action was taken to prevent contaminated groundwater from recontaminating the clean
fill. An interceptor system between the Interurban trail and the East Drain was constructed which
included a well point extraction system was installed in late 1993. Well points were connected to
the Western Processing extraction system for extraction and treatment.
The East Drain interceptor system was operated for 2 years, beginning in November 1994 and was
shut off in December of 1996 as part of the implementation of the containment remediation
strategy and the elimination of the groundwater recharge system.
4.4. Explanation of Significant Differences (ESD)
After eight years of remediation (extraction, surface water infiltration, and treatment) designed
to meet cleanup levels, the Trust submitted a Technical Impracticability Waiver (TIW) request,
stating that the Site could not meet cleanup levels in a reasonable time or at a reasonable cost.
The Governments reviewed the TIW, but did not grant a waiver. Instead, the EPA issued an ESD
in December 1996 as a modification to the ROD to reflect current site conditions and
remediation. The objective of the remedial systems was changed from an aggressive effort to
restore groundwater quality to acceptable levels within 5 to 7 years to containment of the
contamination remaining on site and the prevention of further off-site migration. The
Governments agreed that the modified remedy was fundamentally consistent with the selected
remedy contained in the ROD and amended ROD and would remain protective of human health
and the environment.
The ESD included the following remedial strategies:
Institutional controls,
Containment pumping inside the slurry wall and the trans plume,
RCRA consistent cap over the site,
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Trans plume control,
Long-term monitoring and Five-Year Reviews,
Installation of an isolation slurry wall (separating less contaminated Sector 4 from Sector 1),
Hot spot remediation on-site using bioremediation, thermal reduction and stabilization,
Minimum of 30 years site maintenance, and
Development of a contingency plan for changing conditions.
4.4.1. PostESD
All components of the ESD requiring construction have been completed. The following is a
summary of the work.
1. Engineering and Institutional Controls
Some institutional controls have been established. Passive controls include state regulations,
currently in effect, limiting groundwater use as a drinking water source in the affected area. Active
controls include annual land use notifications and engineering controls of fencing and site security.
The site property is leased by the Trust and they maintain an office at the site. They actively
maintain the site for security, proper fencing and locked gates, treatment plant operations, cap
maintenance and the long term monitoring program as part of their approved O&M plan. However,
ROD required institutional controls in the form of restrictive covenants or deed notices have not
been implemented.
2. Containment Pumping
As part of the containment strategy approved in the ESD, many old EPA wells, special purpose
wells, piezometers, vacuum extraction wells, and infiltration lines were no longer required for
extraction, infiltration, testing, or verification of containment. Between May and November 1997,
after approvals from the Governments, approximately 300 of these "wells" were decommissioned
by licensed drilling companies in accordance with Washington State regulations.
The new extraction system was installed in 1996 to provide automated operation of hydraulic
containment. Fifteen new containment wells, new monitoring wells, and new piezometers were
installed, completely replacing the old vacuum extraction system. Currently there are 17 extraction
wells operating at Western Processing Site (see Figure 1-4).
A new, highly automated, computerized treatment system was constructed concurrently with
the new extraction system for all groundwater extracted during containment operations and
became operational in June 1997. The new system replaced the original system with a
treatment process designed to remove VOCs from extracted groundwater. Treated water is
discharged under permit to the King County POTW. Off gas from the air stripper is carbon-
treated prior to atmospheric release under a Puget Sound Air Pollution Control Agency permit.
The current extraction system, with the trans plume extraction wells off-line, the RCRA cap
securely in place, and pumping to maintain a continual inward groundwater flow gradient within
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the slurry walls, has averaged less than 5 gpm based on annual averages from 2008 to 2012. The
annual average extraction rate has been reduced from 140 gpm in 1996 and 75 gpm in 1997 to the
current rate. The extraction rates have been reduced in conjunction with the change in remedy
focus from restoration to containment. The system is currently operational 7 days per week, 24
hours per day. The system operates 99% of the time.
3.RCRA Cap
The Trust completed work on the placement of a RCRA Cap over Sector 1 (Figure 1-2) in
1999. As of the date of this Five-Year Review, the cap is intact, is visually monitored daily,
remains effective in preventing storm water infiltration and continues to prevent human and
ecological contact with the subsurface contamination.
4. Trans Plume Control
In April 2000, the extraction wells from within the trans plume were shut off as part of an
MNA program that was implemented after detailed government review and approval of a 1999
proposal submitted by the Trust. The proposal and subsequent monitoring data demonstrated
that geochemical conditions in the soils within and surrounding the trans plume area are very
supportive of biological reductive dechlorination of target VOCs.
Monitoring of VOCs (TCE, cis 1,2 DCE, and vinyl chloride) in the trans plume has continued
through 2012. Analysis results have indicated a dramatic decrease in VOC concentrations as
the result of earlier pumping and the later MNA remediation approaches. There were no VOCs
detected above reporting limits in the trans plume area during 2012. The only detection of a
VOC (vinyl chloride) above a laboratory detection limit since 2006 occurred in 2011,
however, the concentration was well below the Contingent Action Criterion action level. The
last VOC concentration in the trans plume area exceeding a Contingent Action Criteria
occurred in 2002. Although the trans plume area is designated as a light industrial/commercial
area, the effectiveness of MNA in treating VOCs to below detection levels eliminates concerns
associated with surface structure vapor intrusion.
5. Mill Creek
The ESD did not change the remedy status of Mill Creek. The Phase II ROD, amended ROD
and Consent Decree called for the remediation of Mill Creek which consisted of removal of
contaminated creek bottom sediment and cover of the east creek bank soil with clean material
after removing the contaminated surficial soil layer. Creek bed sediments were sampled after
dredging was completed in 1993 and found to contain metal contaminants above acceptable
levels. Additional remedial action was taken to isolate contaminants under a minimum 4-inch
gravel bed placed in the creek. Gravel placement was completed in 1994. Monitoring of
surface water quality continues at three stations in Mill Creek: upstream, adjacent to, and
downstream of the Sector 1.
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6. East Drain
Phase II investigation results indicated that certain areas of sediment in the East Drain
contained metals exceeding cleanup levels. Remediation of East Drain sediments was
undertaken in 1993 and included removal of over 1,140 tons of sediment. Class A gravel
borrow was used as backfill material in excavated areas.
A well point extraction system was installed between the Interurban trail and the East Drain to
prevent contaminated groundwater from recontaminating the clean East Drain fill. The extraction
system operated from November 1994 to December of 1996 whereupon it was shut down due to
the implementation of the containment remediation strategy.
7. Long-Term Monitoring and Five-Year Reviews.
The Trust has prepared a long-term monitoring and sampling plan for the Site and Five-
Year Reviews are being conducted.
8. Isolation Wall
The ESD maintained the slurry wall containment remedy but added the construction of a
supplemental isolation wall immediately south of the South 196th Street right-of-way. With the
isolation wall, the area north of South 196th Street, called Sector 4, has been segregated from the
Sector 1 source area. The isolation wall reduced the groundwater pumping necessary to maintain
containment in the highly contaminated Sector 1 source area. Because of the construction of the
isolation wall and the existing low levels of contamination currently found in Sector 4, a RCRA-
type cap was not required. The isolation wall was constructed using a soil-cement-bentonite backfill
material. The mix varies from the original slurry wall mix to provide the additional structural
stability necessary to support the construction of an embankment across the Site for the City of
th
Kent's South 196 Street east- west arterial extension.
9. "Hot Spot" Remediation
The ESD required treatment of an additional 5,000 cubic yards of contaminated soil. Soil samples
were collected and analyzed from two depths at 39 locations. The boundaries of the "hot spot"
were determined through an iterative process designed to identify the 5,000 cubic yards of the
most contaminated (generally chlorinated VOCs >10 mg/kg, aromatic VOCs >20 mg/kg, total
petroleum hydrocarbons [TPH] >10,000mg/kg, and metals >25,000 mg/kg) soil using contour and
risk-enhanced contour plots. Soils were excavated from the "hot spot," and 5761 cubic yards
(8983 tons) of contaminated soil were shipped to the hazardous waste disposal facility in
Arlington, Oregon. The excavation was backfilled with lifts of clean gravel and crushed rock.
Activities began with issuance of a work plan in March 1997 and were completed with regrading
of surface soils in October 1997.
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10. Bioremediation
The ESD identified bioremediation as a possible cleanup alternative for both shallow and
deeper groundwater VOC contamination. Field tests indicated that ongoing natural processes
(intrinsic bioremediation) would not be significantly improved by enhanced bioremediation.
Since there was no technical advantage or cost effectiveness, bioremediation was removed from
active consideration as a cleanup option for Area 1, but it was successfully implemented in the
Sector 3 trans plume area.
11. Site Maintenance
The Trust currently maintains the Site in accordance with various existing work plans. Long-
term maintenance and operations is addressed in the long-term site operations and maintenance
plan approved by the governments in 2009.
12. Contingency Plan
The Final Contingency Plan identifies procedures for evaluating containment and actions
to be taken if those procedures indicate a loss of containment (Contingent Action
Criteria). The Long Term Contingency Plan was approved in March, 2000. The Plan was
updated 2009.
5. PROGRESS SINCE LAST REVIEW
5.1 Protectiveness Statement from the Fourth Five-Year Review:
" The remedy at the Western Processing site currently protects human health and the
environment because the slurry wall, RCRA cap, containment pumping and extraction
treatment system contain the contaminated groundwater and soil within the source area. The
groundwater concentrations off the Western Processing property have decreased and there are
no exposure routes to the site contaminants. Current land use is consistent with Institutional
Control requirements, however, institutional controls that will run with the land are not in
place and still need to be placed on the parcels of property to ensure the remedy remains
protective for the long term
5.2 Status of the Recommendations and Follow-up Actions from Fourth Five-Year Review
The recommendation section from the Fourth Five-Year Review stated that:
"EPA and the Western Processing Trust Fund (the Trust) will need to determine why title to the
property has not passed to a new owner. This will allow discussions with the new owner for the
purpose of implementing land use controls that will run with the land. The Trust will also need to
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initiate discussions with the other four properties that contain portions of the containment cell to
implement land use controls that will run with the land. The ROD and the Consent Decree
require the Trust to implement deed restrictions so that the remedy remains protective of human
health and the environment.
The Western Processing Trust Fund should update the Contingent Action Criteria (CAC) for
critical wells. After the 1995 ESD, EPA approved a containment strategy that contains
procedures and potential contingent actions to be implemented if loss of containment was to
occur. Part of that strategy involved the creation of Contingent Action Criteria (CAC). Since
that time, contaminant concentrations have decreased and some of the current CAC no longer
reflect present site conditions
Although controls such as water use restrictions, engineering controls, and required behavior
from the PRPs are in place, Institutional Controls that implement title restrictions that run with
the land are not in place. The parcels of land where ICs are necessary have been identified and
negotiations on the content of the deed restrictions have begun, but the process has not been
completed.
The delay in implementing the deed restrictions is not affecting the current protectiveness
because the current uses of land are consistent with the planned deed restrictions. The Trust is
actively maintaining the site and the Governments conduct regular oversight, in order to
provide the same protection in the short term that institutional controls are intended to achieve
in the long term.
In 2009, the Trust updated the Contingent Action Criteria (CAC), originally developed in 2000,
to better define criteria levels at which contingent actions might be necessary when
contaminant concentrations exceeded certain calculated levels. The CAC were developed for
each monitoring location and were updated primarily due to the addition of the intervening
years of monitoring data which tended to dampen the statistical variability of expected
concentrations. There have been no exceedences of the CAC since they were updated in 2009.
Other Changes:
As a contingency to the potential failure of the damaged upstream Howard Hanson Dam,
several of the well vaults and their corresponding electrical panels were raised to levels above
the estimated flood plain during November and December of 2009. In addition, this action also
addresses foreseeable climate change impacts.
6. FIVE-YEAR REVIEW PROCESS
The Five-Year Review was conducted according to procedures in OSWER Directive
9355.7-03B-P, Comprehensive Five-Year Review Guidance.
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6.1. Notification ofpotentially interested parties
There has not been any interest expressed from the community in the last five years for
community involvement in regards to this project, so no community involvement activities
have occurred between the last Five-Year Review and the beginning of this Five-Year Review.
Community interest in this site is considered low.
In Mid February, 2013, EPA mailed postcards to the contacts on the site mailing list announcing
the beginning of the Five-Year Review and requesting comments. On March 1, 2013, EPA placed
a Public Notice in the Kent Reporter stating that EPA was preparing this Five-Year Review and to
solicit any comments. At that same time, the public notice was published on the EPA Region 10
website. No comments have been received by EPA.
This review will be publicly available on CD and as a hard copy at the Kent Regional Library, at
the EPA Region 10 office, and will be available in PDF format on the EPA Region 10 Western
Processing web page.
6.2. Review of site-related documents
This Five-Year Review consisted of a review of relevant, site-related documents including RODs
for each OU, the Amendment to the ROD, ESD, monitoring reports, and recent monitoring data. A
list of the documents reviewed can be found in the Appendix.
6.3. Site Visit, Inspection, and Interviews
A site visit was conducted on February 6, 2013. The purpose of the site visit was twofold:
1. To conduct interviews and
2. To observe site conditions as part of the Five-Year Review
A site inspection checklist was completed during the visit and is attached in the
Appendix with labeled photographs that support the findings from that visit.
The remedy appeared to be operating effectively as designed. A few issues addressing weed
growth and mole presence were discussed during the inspection. These issues do not appear to be
substantive problems nor do they affect current or future protectiveness. Trust staff stated that they
address these issues as a part of ongoing Site maintenance activities.
None of the identified issues were out of the ordinary for the type of site and setting of the
site. EPA believes that the results of this inspection indicate that the onsite O&M is adequately
implemented and is protective of the remedy.
The RCRA cap and drainage system are well maintained and appear to functioning as
designed.
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6.4. Site Conditions and
Progress
The Western Processing site remains fenced with access controlled by on-site personnel. The
Site groundwater extraction system has operated continuously with only very brief shut-
downs for routine maintenance. See Figure 1-4 for Containment Extraction system well
locations.
As a result of the City of Kent's plans to construct a 72nd Avenue S extension along the east
edge of the property over Mill Creek, several well/peizometer modifications were necessary.
The modifications include raising several wellheads to finish grade elevation of the proposed
new roadway and decommissioning other wells. All actions were approved by the
Governments in 2009. No other impacts to the Site are anticipated. The Trust moved its
office building in 2010 in anticipation of the construction of the new roadway which has yet
to begin as of September 2013.
6.5. Data Review
The treatment plant has operated continuously in compliance with the King County water
discharge permit and a Puget Sound Air Pollution Control Agency permit and with only very
brief shut-downs for routine maintenance. During 2011 the treatment plant processed 2.6
million gallons of water at an average pumping rate of 5.0 gallons per minute, while
extracting 2.4 lbs. of zinc and 102 lbs of volatiles.
Groundwater quality monitoring results have indicated a strong downward trend for the
contaminants of concern for wells in the trans plume area (Sector 3). Cis-1,2-DCE
concentrations in the "trans plume" were not detected in the extraction wells (T wells) in 2012.
Vinyl chloride, a breakdown product of cis-1,2 DCE, was detected above detection levels in 2 of
85 samples, but upon resampling, was non-detect. Otherwise, VOCs in the trans plume area have
only been detected once in one location since 2006 and that result was significantly below the
Contingent Action Criteria for that location. VOC concentrations have decreased over time,
showing strong evidence that natural attenuation is occurring vigorously throughout the trans
plume area. Mill Creek surface water quality monitoring data do not reflect contamination from
the Site although occasional sampling analysis results register exceedences in AWQC originating
upstream of the Site. The source of these impacts is not known.
In accordance with the 1996 Interim Period Site Monitoring Plan, sediment quality is no longer
monitored at the Western Processing Site. However, sediment sampling analysis results from 1996
for PAH concentrations in the East Drain significantly exceed the WDOE Freshwater Sediment
Standards adopted in September 2013. Although surface water quality sampling does not indicate
exceedances of the Ambient Water Quality Criteria, the comparison of the new freshwater
sediment standards to the 1996 sediment sampling results may be an indication that protectiveness
for freshwater benthic biota is being compromised. However until additional evaluation of the
sediment contamination in the East Drain and Mill Creek can be conducted, a determination of
protectiveness cannot be made.
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7. TECHNICAL ASSESSMENT:
7.1. Question A: Is the remedy functioning as intended by the decision documents?
Yes. The review of documents and data, and the results of the site inspection indicate that the
remedy is functioning as intended by the ROD, ROD Amendment and ESD. The RCRA cap and
slurry wall are in place and fully functioning; the extraction system and treatment plant maintain
hydraulic containment and treatment of extracted groundwater; O&M is being implemented as
approved; monitoring data trends are showing decreases from within the Sector 1 slurry walls.
Contaminant concentrations in the off-site trans plume area have decreased through natural
attenuation to levels below detection limits. Except for occasional metals spikes originating
upstream in Mill Creek, Mill Creek and the East Drain remain in compliance with 1986 AWQC.
However, although many institutional and engineering controls have been implemented, required
deed restrictions for parcels of land in the source area have not been put in place. The purpose of
the deed restrictions is to ensure that current or future property owners do not damage the
containment system and to prevent contact with existing subsurface soil and groundwater
contamination. The delay in implementing the deed restrictions is not affecting the current
protectiveness because the current uses of land are consistent with the planned deed restrictions.
The Trust is actively maintaining the site and the Governments conduct regular oversight, in
order to provide the same protection in the short term that institutional controls are intended to
achieve in the long term. In order to ensure protectiveness in the long-term, institutional controls
in the form of restrictive covenants or deed restrictions that run with the land are required for
parcels in Sectors 1 and 2.
7.2. Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial
action objectives (RAOs) used at the time of the remedy still valid?
Unknown. Changes in TCE toxicity values would affect protectiveness in the off-site trans plume
area except that TCE is below analytical detection limits in this area. Although TCE remains a
contaminant of concern in the Sector I containment area, the release of TCE or other
contamination is prevented by the slurry wall, continual hydraulic containment and the RCRA
cap.
The State of Washington recently promulgated freshwater sediment standards (effective
September 1, 2013). Sediment analytical data collected post remedy implementation (1996) in the
East Drain show PAH concentrations considerably higher than the new State standards. Although
PAHs were a contaminant of concern at the site, no PAH cleanup level in sediment was
established and no ARARs related to sediment were identified at the time of the ROD or ROD
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Amendment. Additional evaluation is necessary to determine the current level of PAH
contamination in the sediment, whether this contamination is related to the Site, and whether,
considering the newly promulgated State sediment standards, this information impacts the
protectiveness of the sediment portion of the remedy.
The site remains zoned industrial and the surface soil cleanup levels are consistent with industrial
use. With the exception of the above concerns related to the protectiveness of the sediment
portion of the remedy, the exposure assumptions, toxicity data, cleanup levels, and remedial action
objectives (RAOs) are still valid.
7.3. Question C: Has any other information come to light that could call into
question the protectiveness of the remedy?
No. Hazardous substances remain onsite in the subsurface soils and in the groundwater within
the confines of the slurry wall and RCRA cap. As a result, all required Institutional Controls
must be developed and implemented to prevent exposure to potentially hazardous substances and
prevent the installation of onsite wells. The Trust is actively maintaining Engineering Controls at
the site and the Governments conduct regular oversight. At this time, these actions provide the
same protection in the short term that institutional controls in the form of deed restrictions are
intended to achieve in the long term.
In addition, as discussed above, a potential protectiveness issue related to the sediment portion
of the remedy has been identified. In order to determine whether this portion of the remedy
remains protective, additional evaluation is necessary.
7.3.1 Potential Climate Change Impacts
Mill Creek is located on the western side of the property, and is a rain dominated watershed
with a period of peak flow between December 15 and March 1. Current climate models have a
lower degree of certainty in precipitation impacts, but most models project a slight increase in
precipitation during the fall and winter months. Portions of the Western Processing Superfund
site are located within the 100 year flood plain and climate change related increases in winter
precipitation could present an increased flood risk for the site in the future. However, in 2009,
as a contingency to the potential failure of the damaged upstream Howard Hanson Dam, well
vaults and their corresponding electrical panels at risk to flood impacts were raised to levels
above the estimated dam failure flood plain. As the projected climate change related
precipitation changes are smaller than 20th century year-to-year variability, this modification
easily protects the site from foreseeable climate change impacts.
7.4 Technical Assessment Summary
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With the exception of the deed restrictions, the site data and site inspection reports show that all
other elements of the remedy have been properly implemented, are functioning as intended by the
ROD and are effectively maintained by the approved O&M plan. The delay in implementing the
deed restrictions has no effect on the current protectiveness but could affect long term
protectiveness. There have been no physical changes of the site that would affect the
effectiveness of the implemented remedial actions. Surface and groundwater exposure routes are
under control. However, protectiveness of freshwater sediment may be in question due to
elevated levels of PAHs in 1996 post remedy sampling in the East Drain and the promulgation of
the new Washington Department of Ecology freshwater sediment standards (became effective
September 2013). Additional sampling and evaluation is necessary to assess protectiveness in the
East Drain and Mill Creek sediments.
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8. ISSUES
The major issues concerning this site are presented in the table below.
Table of Issues
Issues
Affects
Protectiveness
(Y/N)
Current
Future
Permanent Institutional Controls need to be developed and
implemented that run with the land in Sector 1.
N
Y
Concentrations of PAHs in the East Drain are elevated above
the State of Washington's new Freshwater Sediment Standards calling
into question the protectiveness of the sediment portion of the remedy.
Unknown
Unknown
9. RECOMMENDATIONS AND FOLLOW-UP ACTIONS
Table of Recommendations and Follow-up Actions
Recommendations
/Follow-up
Actions
Party
Responsible
Oversight
Agency
Milestone
Date
Follow-up Actions:
Affects Protectiveness
(Y/N)
Current
Future
Develop and implement
required
Institutional Controls
Trust
EPA
9/30/18
N
Y
Evaluate PAH concentrations
in Mill Creek and East Drain
and determine whether the
contamination found is related
to the site. Determine whether
the sediment remedy is
protective.
Trust
EPA &
WDOE
9/30/15
Unknown
Unknown
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10. STATEMENT OF PROTECTIYENESS:
Based on this Technical Assessment, a protectiveness determination related to the remedy
for the Western Processing Site cannot be made at this time. Additional data needs to be collected
for the sediment portions of the remedy (East Drain and Mill Creek) to ensure they remain
protective. With the exception of these sediment areas, the remedy currently protects human health
and the environment in the short term because the contaminated groundwater and soil in the
source area are contained within the slurry wall, the RCRA cap and the containment pumping
and treatment system. The groundwater concentrations off the Western Processing property have
decreased to below detection levels. There are no current exposures to site contaminants related
to these portions of the remedy. However, for the remedy to be protective in the long term,
institutional controls that will run with the land need to be placed on the properties located within
the area bounded by the slurry wall.
11. NEXT REVIEW
Based on site conditions, and the fact that hazardous substances remain on site, the next Five-
Year Review is required five years; from the signature date of this Five-Year Review in 2018.
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APPENDICES
Documents Reviewed
Figures*
Site Inspection Check List
Site Photographs
*Figures reproduced from 2011 Annual Report, Western Processing, Landau Associates
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Appendix: List of Documents Reviewed
Record of Decision, U.S. EPA, August, 1984.
Record of Decision, U.S. EPA, September, 1985.
Amended Record of Decision, U.S. EPA, September, 1986.
Copy of Western Processing Consent Decree, filed October 16, 1986.
Copy of Western Processing Consent Decree, filed April 10, 1987.
Explanation of Significant Differences, Western Processing Superfund Site, U.S. EPA, December
11, 1995.
1996 Annual Evaluation Western Processing, Landau Associates September 1, 1998
1997 Annual Evaluation Western Processing, Landau Associates December 31, 1998
1998 Annual Evaluation Western Processing, Landau Associates September 14,1999
2008 Annual Evaluation Western Processing, Landau Associates Junel6, 2009
2009 Annual Evaluation Western Processing, Landau Associates June 9, 2010
2010 Annual Evaluation Western Processing, Landau Associates JunelO, 2011
2011 Annual Evaluation Western Processing, Landau Associates Junel 1, 2012
2012 Annual Evaluation Western Processing, Landau Associates June 3, 2013
Evaluation Report, MNA, April 2000-January 2002, Western Processing, Landau Associates
8/23/02
Monitored Natural Attenuation Annual Summary - 2002 Western Processing
Landau Associates, March 19, 2003
The Second Five Year Review, EPA 9/98
The Third Five-Year Review Report, Western Processing, EPA 9/03
The Fourth Five-Year Review Report, Western Processing, EPA 7/2008
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Location
(jffSik
Associates
Western Processing
Kent, Washington
Vicinity Map
TT
Figure
35
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Figure
Landau
Associates
Western Processing
Kent, Washington
Site Plan
1-2
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15M40Bฉ Long-Term Groundwater Monitoring Locotion
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A2:
Site Inspection Checklist
I. SITE INFORMATION
Site name: Western Processing
Date of inspection: February 6, 2013
Location and Region: Kent, WA; R10
EPA ID: WAD0009487513
Agency, office, or company leadingthe
Five-Year Review: EPA Region 10
Weather/temperature: 45ฐF, Overcast to Partly
Cloudy
Remedy Includes: (Check all that apply)
^.andfill cover/containment
^\ccess controls
institutional controls
^Groundwater pump and treatment
^Surface water collection and treatment
XOther: Surface water monitoring for Mi
^Monitored natural attenuation
^Groundwater containment
^/ertical barrier walls
II Creek
Attachments: ^Inspection team roster attached QSite map attached
^ Inspection team roster on bottom of page
II. INTERVIEWS (Check all that apply)
1. O&M site manager: Wayne Schlappi Project Manager Februarv6, 2013
Name Title Date
Interviewed ^tsite Qat office Q)y phone Phone no. 425-965-4177
Problems, suggestions; QReport attached
2. O&M staff: Ken Brown SeniorTechnician 3 Februarv6, 2013
Name Title Date
Interviewed ^tsite Qat office Qpy phone
Problems, suggestions; QfReport attached
Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency
response office, police department, office of public health or environmental health, zoning
office, recorder of deeds, or other city and county offices, etc.) Fill in all that apply.
There were no other regulatory agencies present during the inspection. The
Washington Department of Ecology representative opted out of attendance at the
inspection.
Inspection Team:
Joe Wallace
Bernie Zavala
EPA Region 10, Remedial Project Manager
EPA Region 10, Hydrogeologist
206-553-4470
206-553-1562
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III. ON SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)
1. O&M Documents
^O&M manual ^ Readily available ~ Up to date ~ N/A
^\s-built drawings ^ Readily available ~ Up to date ~ N/A
^Maintenance logs ^ Readilyavailable ~ Uptodate ~ N/A
Remarks: The maintenance log and inspection notebook displayed that maintenance logs are
being maintained and that the inspections are being performed.
Site-Specific Health and Safety Plan ^Readily available ~Uptodate QM/A
l^ontingency/emergency response plan ^Readily available ~Jptodate QM/A
Remarks: I did not verifvthese elements during the interviewand inspection.
O&M and OSH A Training Records ^Readily available
Remarks: HAZWOPER certification is current.
^Jp to date Q^l/A
6.
7.
Permits and Service Agreements
^\ir discharge permit
~Affluent discharge
^A/aste disposal, POTW
~Other perm its
Remarks
^Readily available
~ Readily available
^ Readily available
~Readily available
^ Up to date
~ Up to date
^ Up to date
~JJpto date
~ N/A
^ N/A
~ N/A
~M/A
Gas Generation Records
Remarks
~Readily available ~Jptodate ^M/A
Settlement Monument Records
~Readily available ~Jptodate ^M/A
Groundwater Monitoring Records
Remarks
^Readily available ^Jptodate QM/A
Groundwater Extraction Records
Remarks
^Readily available ^Jptodate ^M/A
Discharge Compliance Records
Air
Water (effluent)
Remarks
^Readily available
^Readily available
|^|Jpto date
|^|Jpto date
QJ/A
QJ/A
10. Daily Access/Security Logs ~Readily available ~Jptodate ฎ/A
Remarks: The sector is fenced off with a securitygate. Eithera combination or an electronic
pass card is necessarvto open the gate. All well vaults were padlocked. None of
the waste material remains on t he surface, so there is not a surface waste hazard
that needs to be secured.
IV. O&M COSTS
1.
O&M Organization
~ State in-house
~Contractor for State
~ PRP in-house
^Contractor for PRP
~ Federal Facility in-house
~Contractor for Federal Facility
~ Other
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2. O&M Cost Records
~ Readily available QUp to date
^ Funding mechanism/agreement in place
Original O&M cost estimate ~ Breakdown attached
Total annual cost by year for review period if available
From 1/1/2007 To 12/31/2007 $600,000 ~ Breakdown attached
Date Date Total cost
Remarks: Per Wayne Schlappi, costs dropped to around $600,000 per year since the
containment strategy was adopted and implemented, and have remained around
$600,000 per year.
3. Unanticipated or Unusually High O&M Costs During Review Period
Describe costs and reasons: not applicable.
V. ACCESS AND INSTITUTIONAL CONTROLS 0 Applicable ~ N/A
A. Fencing
1.
Fencing
Remarks:
^ntact Q-Ocation shown on site map
B. Other Access Restrictions
1. Signs and other security measures Q-ฐcation shown on site map QWA
Remarks: The road is blocked by a gate that requires an access key to enter. All of the
other observed fence gates were locked with padlocks, as were the the observed
well vaults. Ken Brown and Wayne Schlappi informed me that the water
treatment building has an entry alarm system.
C. Institutional Controls (ICs)
1. Implementation and enforcement
Site conditions imply ICs not properly implemented Qfes ^Mo CN/A
Site conditions imply ICs not being fully enforced Qfes ^Mo Q^/A
Type of monitoring:
Frequency
Responsible party/agency
Contact: Wayne Schlappi
Name
Self-reporting by the Trust: office on site.
Varies: monthly to every other year. See table 1.
Western Processing Trust Fund.
Project Manager Februarv6, 2013 425-965-4177
Title Date Phone no.
Reporting is up-to-date
Reports are verified by the lead agency
^es
^es
CP 0
UP*
Specific requirements in deed or decision documents have been met
EKes IEINo
Violations have been reported ~ Yes ^ No
Other problems or suggestions: QReport attached
QJ/A
QJ/A
~ N/A
~ N/A
41
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2.
Adequacy C)Cs are adequate ^Cs are inadequate QM/A
Remarks: Enqineered Controls are in place and effective. However, title to the property
has not passed on to anv heirs or successors of the estate a this time. After that occurs,
EPA will resume discussions for implemented the restrictive covenants on the title.
D.
General
1.
Vandalism/trespassing Q.ocation shown on site map ^Mo vandalism evident
Remarks:
2.
Land use changes on site ^M/A
3.
Land use changes off site ^M/A
Remarks: The Citv of Kent is planninq to extend 72Avenue across the east edqe of
the Western Processina site, but at this time there have not been anv
land use chanaes.
VI. GENERAL SITE CONDITIONS
A.
Roads ^Applicable Q^l/A
1.
Roads damaged ^Location shown on site map ^Roads adequate
B.
OtherSite Conditions
Remarks:
I inspected some of the storm qrates on Site, a storm water outfall at Mill Creek, a
few discharqe lines from the RCRA cap into East Drain, the overflow area from the detention
oond,
and the discharqe line from the detention oond into Mill Creek. These were all clear
of obstruction. There is a lot of veqetativearowth in and around the detention oond.
VII. LANDFILL COVERS 0 Applicable ~ N/A
A.
Landfill Surface
1.
Settlement (Low spots) ||Location shown on site map ^Settlement not evident
Areal extent Depth
Remarks No settlement was evident in the area covered bv the RCRA Cap.
2.
Cracks ^j-ocation shown on site m ap ^racking not evident
Lenqths Widths Depths
Remarks
3.
Erosion ^j-ocation shown on site m ap ^rosion not evident
Areal extent Depth
Remarks
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4.
Holes Q.ocation shown on site map floles not evident
Areal extent Depth
Remarks: A few small mole hole mounds were noted in the surface soils.
5.
Vegetative Cover ^Grass ^Cover properly established signs of stress
Ql"rees/Shrubs (indicate size and locations on a diagram)
Remarks: Some trees were previously startina to establish themselves at the western
fence line for Sector 4, but these trees have been removed. There were
several Scotch Broom plants in Sector 4 and the detection pond.
6.
Alternative Cover (armored rock, concrete, etc.) fl/A
Remarks
7.
Bulges Q_ocation shown on site m ap ^pulges not evident
Areal extent Heiqht
Remarks
8.
Wet Areas/Water Damage ^A/et areas/water damage not evident
~Wet areas ~ Location shown on site map Areal extent_
~Ponding ~ Location shown on site map Areal extent_
~Seeps ~ Location shown on site map Areal extent_
~Softsubgrade ~ Location shown on site map Areal extent_
Remarks: None
9.
Slope Instability
~Slides ~-ocation shown on site map ^Mo evidence of slope instability
Areal extent
Remarks
B.
Benches ~Applicable fl/A
(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt
theslope in orderto slowdown the velocity of surface runoff and interceptand conveythe
runoff to a lined channel.)
C.
Letdown Channels ~Applicable fl/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.)
D.
Cover Penetrations ^Applicable |H|M/A
1.
Gas Vents ~Active ^passive
~Properly secured/locked functioning ~Routinely sampled ~Good condition
~Evidence of leakage at penetration ~Meeds Maintenance fl/A
Remarks
2.
Gas Monitoring Probes
~Properly secured/locked functioning ~Routinely sampled ~Good condition
~Evidence of leakage at penetration ~Meeds Maintenance fl/A
Remarks
3.
Monitoring Wells (within surface area of landfill)
froperly secured/locked functioning ^Routinely sampled ^Good condition
~Evidence of leakage at penetration QMeeds Maintenance QJ/A
Remarks
43
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4. Containment Wells
froperly secured/locked functioning ^Routinely sampled ^Good condition
~Evidence of leakage at penetration ~Meeds Maintenance QJ/A
Rem arks
5. Settlement Monuments ~_ocated ~Routinely surveyed fl/A
Rem arks
E. Gas Collection and Treatment ~Applicable fl/A
F. Cover Drainage Layer ^Applicable d^l/A
1. Outlet Pipes Inspected functioning |Z|M/A
Rem arks
2. Outlet Rock Inspected ~Functioning fl/A
Rem arks
G. Detention/Sedimentation Ponds ^Applicable d^l/A
1. Siltation Areal extent Depth d|M/A f5iltation not evident
Rem arks
2. Erosion Areal extent Depth ^Erosion not evident
Rem arks
3. Outlet Works functioning d|M/A
Rem arks
4. Spillover functioning d|M/A
Rem arks
H. Retaining Walls ~Applicable fl/A
I. Perimeter Ditches/Off-Site Discharge ^Applicable d|M/A
1. Siltation ~.ocation shown on site map ^Siltation not evident
Areal extent Depth
Rem arks
2. Vegetative Growth ~.ocation shown on site map QM/A
f/egetation does not im pede flow
Areal extent Type
Remarks: Vegetation was encroaching on some of the drainage grates, but is
regularly cleared. I saw no vegetative debris eitherthat would impede flow.
3. Erosion ~.ocation shown on site map ^prosion not evident
Areal extent Depth
Rem arks
4. Discharge Structure ^Functioning QJ/A
Rem arks
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VIII. VERTICAL BARRIER WALLS 0 Applicable ~ N/A
1.
Settlement ~-ocation shown on site map ^Settlement not evident
Areal extent Depth
Remarks
~2~
Performance Monitoring
Remarks: Described in detail within this Five-Year Review.
A.
Treatment System ^Applicable QJ/A
1.
Treatment Train (Check components that apply)
~Vletals removal ~ Oil/water separation ~ Bioremediation
^\ir stripping ^Carbon adsorbers
~filters
~^dditive (e.a.. chelation aaent.flocculent): metals seauesterina aaents.
~Others
^Good condition QNeeds Maintenance
^Sampling ports properly marked and functional
^Sampling/maintenance log displayed and up to date
Equipment properly identified
^Quantity of qroundwatertreated annually
~Quantity of surface watertreated annually: not applicable.
Remarks: Floor is clean, instruments and flow lines are clearly labeled, walkways
are kept clear. The control system, as explained by Wayne Schlappi and Ken
Brown, contains redundant safety mechanisms, includinq qenerator and
battery backupto send an alarm via paaer in the event of a powerfailure.
2.
Electrical Enclosures and Panels (properly rated and functional)
~si/A ^Good condition ~Needs Maintenance
Remarks: Approximately 1" of water is on the bottom of the vaults, and enters
the lowermost electrical enclosures. W avne Schlappi stated that the sump
pumps need a small amount of suction head, which is why the water is present,
and that they have verified that all of the connections within the lower enclosures
are completelvencased.
3.
Tanks, Vaults, Storage Vessels
~si/A ^Good condition ~Propersecondary containment ~Needs
Maintenance
Remarks:
4.
Discharge Structure and Appurtenances
~(M/A ^Good condition QNeeds Maintenance
Remarks
5.
T reatment Building(s)
~M/A ^]Good condition (esp. roof and doorways) QNeeds repair
~Chemicals and equipment properly stored
Remarks
6.
Monitoring Wells (containment remedy)
properly secured/locked ^Functioning ^Routinely sampled ^Good condition
~Ml required wells located ~ Needs Maintenance QN/A
Remarks
45
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B. Monitoring Data
1. Monitoring Data
Kls routinely submitted on time
^ Is of acceptable quality
2. Monitoring data suggests:
^Groundwater plume is effectively contained
^Contaminant concentrations are declining
C. Monitored Natural Attenuation
1. Monitoring Wells (natural attenuation remedy)
^ Properly secured/locked ^Functioning ^Routinely sampled ^Good condition
~ All required wells located ~Needs Maintenance QN/A
Rem arks
X. OTHER REMEDIES
The Sector 3 groundwater (Trans-Plume) outside of the slurry wall/RCRA cap containment area
is being successfully addressed through monitored natural attenuation. Monitoring and
geochemical sampling results overthe years indicate conditions very conducive to the natural
biodegradation of TCEto cis-1,2,DCE, then to vinyl chloride. The final breakdown constituent,
vinyl chloride is nearing non-detect levels, an order of magnitude below Action Criteria.
XI. OVERALL OBSERVATIONS
A. Implementation of the Remedy
Describe issues and observations relating to whetherthe remedy is effective and functioning as
designed. Begin with a brief statement of what the remedy is to accomplish (i.e., to contain
contaminant plume, minimize infiltration and gas emission, etc.).
The remedy selected for the Western Processing site involves containment of the
source contaminants on site through the use of barrier walls, a RCRA cap, and sufficient
extraction of groundwater to prevent outward migration. After a study showed the area to
be an ideal site for monitored natural attenuation, the pump and treat system was turned off
in April of
2000.
The remedy is functioning as intended and is described in detail earlier in this Five-Year
Review. The Monitored Natural Attenuation of the trans plume is ongoing and effective.
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.
There were a few issues that were identified during the inspection, many of which were pointed
out by representatives of the Trust, such as weed growth and mole presence, but none of
these issue appear to be a long-term or recurring problem. Trust staff stated that they would
take care of these issues as soon as they were identified.
None of the identified issues were out of the ordinary for the type of site and setting of the site.
EPA believes that the results of this inspection indicate that the onsite O&M is adeguatelv
implemented and is protective of the remedy.
46
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C. Early Indicators of Potential Remedy Problems
Describe issues and observations such as unexpected changes in the cost or scope of O&M or
a high frequency of unscheduled repairs that suggest that the protectiveness of the remedy
may be compromised in the future.
The inspection did not identify an v indicators of a potential remedy problems.
D. Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the
remedy.
The system has been in operation long enough that there is enough data for a
proper statistical analysis, and prior to the start of the inspection, we discussed the
possibility of using statistical methods for Long Term Monitoring Optimization. EPA used
the MAROS (Monitoring and Remediation Optimization System) Software for an analysis at
the Frontier Hard Chrome site, to good effect.
The analysis would focus on the adeguacv of the sampling frequency and locations based
on the data collected over several years. It is guite possible that this may indicate that
the sampling frequency at some of the wells could be reduced. This will be discussed in
more detail afterthe T rust has had the opportunity to become familiar with these methods.
47
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1. WWTP control panel screen showing WWTP systems.
2. WWTP control panel screen showing well network.
48
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3. Information on well operation called up on control panel screen.
4. Monitoring well vault raised to protect well from flooding due to potential Howard Hanson Dam
failure.
49
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6. Monitoring well vault with sampling tubes.
50
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7. Monitoring well with raised electrical panel for flood protection.
8. Piezometer
51
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9. One of the storm drains on the RCRA cap.
10. Storm drain discharge point into Mill Creek.
52
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11. Looking West to neighboring warehouse. Ecology blocks set to protect fence from trucks (a past
problem).
12. Vegetative growth on RCRA cap. Note mole tunnel mound.
53
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13. Mole hole on RCRA cap.
14. View to South over RCRA cap. Note mole tunnel mounding.
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15. Small animal access under East side fenceline.
16. Interurban bike trail along East edge of Site.
55
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18. S. 196th St. bridge abutment (West end) built on RCRA cap.
57
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20. Piezometer in Detention Pond
21. Kity of Kent Public Notic of pending Mill Creek restoration work North of Site.
58
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23. Abandoned tank near Mill Creek - will be removed.
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25. Barrels of collected cuttings from geophysical borings in preparation for 72 Ave S. extension.
Collected soil disposed of through Waste Management.
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